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生命起源 Abiogenesis
2021-02-02T06:48:41Z
<p>Thingamabob:</p>
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<div>生命起源<br />
此词条暂由Solitude初步翻译。正由Steve Luo审校,给您阅读带来不便,还请谅解。<br />
审校总结:缺乏对应英文/英文缺失 4 处;英文原文错误: 1 处;英文翻译不确定: 1 处;增加讨论:9 处;增加评论:1 处。<br />
后面很大一部分文本缺乏 纯英文文本部分,导致中英文对应审校比较累<br />
审校疏忽:忘了把引用部分插入中文文本中<br />
{{short description|The natural process by which life arises from non-living matter}}<br />
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{{Redirect|Origin of life|non-scientific views on the origins of life|Creation myth}}<br />
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{{distinguish|Biogenesis}}<br />
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{{For|the oldest life forms| Earliest known life forms}}<br />
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{{Use American English|date=December 2019}}<br />
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[[File:Champagne vent white smokers.jpg|thumb|upright=1.5|The [[earliest known life forms|earliest known life-forms]] on [[Earth]] are putative fossilized [[microorganism]]s, found in [[Hydrothermal vent|hydrothermal vent precipitates]], that may have lived as early as 4.28 Gya (billion years ago), relatively soon after the [[ocean]]s [[Origin of water on Earth#Water in the development of Earth|formed 4.41 Gya]], and not long after the [[Age of the Earth|formation of the Earth]] 4.54 Gya.<ref name="NAT-20170301" /><ref name="NYT-20170301" />]]<br />
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The earliest known life-forms on Earth are putative fossilized microorganisms, found in hydrothermal vent precipitates, that may have lived as early as 4.28 Gya (billion years ago), relatively soon after the oceans formed 4.41 Gya, and not long after the formation of the Earth 4.54 Gya.<br />
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地球上已知最早的生命形式是在热液喷口沉淀物中发现的假定化石微生物,它们可能早在42.8亿年前就已活着,相对而言,是在44.1亿年前海洋形成的不久之后,以及是45.4亿年前地球形成的不长时间后。<br />
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In [[evolutionary biology]], '''abiogenesis''', or informally the '''origin of life''' (OoL),<ref>{{cite book| last1 = Oparin| first1 = Aleksandr Ivanovich| author-link1 = Alexander Oparin| translator1-last = Morgulis| translator1-first = Sergius| year = 1938| title = The Origin of Life| url = https://books.google.com/books?id=Jv8psJCtI0gC| series = Phoenix Edition Series| edition = 2| location = Mineola, New York| publisher = Courier Corporation| publication-date = 2003| isbn = 978-0486495224| access-date = 2018-06-16}}</ref><ref name=Pereto /><ref name="AST-20151218">Compare: {{cite journal |author= Scharf, Caleb |title= A Strategy for Origins of Life Research |date= 18 December 2015 |journal= [[Astrobiology (journal)|Astrobiology]] |volume= 15 |issue= 12 |pages= 1031–1042 |doi= 10.1089/ast.2015.1113 |display-authors= etal |pmid= 26684503 |pmc= 4683543|bibcode= 2015AsBio..15.1031S | quote = What do we mean by the origins of life (OoL)? [...] Since the early 20th century the phrase OoL has been used to refer to the events that occurred during the transition from non-living to living systems on Earth, i.e., the origin of terrestrial biology (Oparin, 1924; Haldane, 1929). The term has largely replaced earlier concepts such as abiogenesis (Kamminga, 1980; Fry, 2000).}}</ref>{{efn|Also occasionally called biopoiesis (Bernal, 1960, p. 30)}} is the [[natural]] process by which [[life]] has arisen from non-living matter, such as simple [[organic compound]]s.<ref name=Oparin>{{harvnb|Oparin|1953|p=vi}}</ref><ref name=Pereto>{{cite journal|last= Peretó |first= Juli |year= 2005 |title= Controversies on the origin of life |url= http://www.im.microbios.org/0801/0801023.pdf |journal= [[International Microbiology]] |volume= 8 |issue= 1 |pages= 23–31 |pmid= 15906258 |accessdate= 2015-06-01 |url-status= dead |archiveurl= https://web.archive.org/web/20150824074726/http://www.im.microbios.org/0801/0801023.pdf |archivedate= 24 August 2015 |quote = Ever since the historical contributions by Aleksandr I. Oparin, in the 1920s, the intellectual challenge of the origin of life enigma has unfolded based on the assumption that life originated on Earth through physicochemical processes that can be supposed, comprehended, and simulated; that is, there were neither miracles nor spontaneous generations.}}</ref><ref>{{cite journal |last1= Warmflash |first1= David |last2= Warmflash |first2= Benjamin |date= November 2005 |title= Did Life Come from Another World? |journal= [[Scientific American]] |volume= 293 |issue= 5 |pages= 64–71 |doi= 10.1038/scientificamerican1105-64|pmid= 16318028 |bibcode= 2005SciAm.293e..64W | quote = According to the conventional hypothesis, the earliest living cells emerged as a result of chemical evolution on our planet billions of years ago in a process called abiogenesis.}}</ref><ref>{{harvnb|Yarus|2010|p=47}}</ref> While the details of this process are still unknown, the prevailing scientific hypothesis is that the transition from non-living to living entities was not a single event, but an evolutionary process of increasing complexity that involved molecular [[self-replication]], [[self-assembly]], [[autocatalysis]], and the emergence of [[cell membrane]]s.<ref>{{cite journal|url=http://www.biocommunication.at/pdf/publications/biosystems_2016.pdf |title=Crucial steps to life: From chemical reactions to code using agents|journal=Biosystems|volume=140|pages=49–57|doi=10.1016/j.biosystems.2015.12.007|pmid=26723230|year=2016|last1=Witzany|first1=Guenther}}</ref><ref name="AB-20141208">{{cite web |last= Howell |first= Elizabeth |title= How Did Life Become Complex, And Could It Happen Beyond Earth? |url= https://www.astrobio.net/origin-and-evolution-of-life/life-become-complex-happen-beyond-earth/ |date= 8 December 2014 |work= [[Astrobiology Magazine]] |accessdate= 14 February 2018 }}</ref><ref name="EA-20150420">{{Cite book |last= Tirard |first= Stephane |title= Abiogenesis – Definition|date= 20 April 2015 |doi= 10.1007/978-3-642-27833-4_2-4 |journal= Encyclopedia of Astrobiology|pages= 1 | quote = Thomas Huxley (1825–1895) used the term abiogenesis in an important text published in 1870. He strictly made the difference between spontaneous generation, which he did not accept, and the possibility of the evolution of matter from inert to living, without any influence of life. [...] Since the end of the nineteenth century, evolutive abiogenesis means increasing complexity and evolution of matter from inert to living state in the abiotic context of evolution of primitive Earth. |isbn= 978-3-642-27833-4 }}</ref> Although the occurrence of abiogenesis is uncontroversial among scientists, its possible mechanisms are poorly understood. There are several principles and hypotheses for {{em|how}} abiogenesis could have occurred.<ref>{{Cite book |title=Rethinking evolution: the revolution that's hiding in plain sight |last=Levinson |first=Gene |publisher=World Scientific |year=2020 |isbn=978-1786347268 |url=https://rethinkingevolution.com/}}</ref><br />
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In evolutionary biology, abiogenesis, or informally the origin of life (OoL), is the natural process by which life has arisen from non-living matter, such as simple organic compounds. While the details of this process are still unknown, the prevailing scientific hypothesis is that the transition from non-living to living entities was not a single event, but an evolutionary process of increasing complexity that involved molecular self-replication, self-assembly, autocatalysis, and the emergence of cell membranes. Although the occurrence of abiogenesis is uncontroversial among scientists, its possible mechanisms are poorly understood. There are several principles and hypotheses for abiogenesis could have occurred.<br />
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在进化生物学中,自然发生,或通俗地称为生命起源(OoL),是生命从非生命物质(如简单的有机化合物)中产生的自然过程。 虽然这一过程的细节仍未可知,但主流的科学假说认为,从非生命实体到生命实体的转变不是一个单一的事件,而是一个复杂度逐渐增加的进化过程,其中包括分子的自复制、自组装、自催化和细胞膜的出现。虽然自然发生的发生在科学家中是没有争议的,但其可能的机制我们却不甚了解。关于自然发生如何发生,有几种原理和假说。<br />
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The study of abiogenesis aims to determine how pre-life [[chemical reaction]]s gave rise to life under conditions strikingly different from those on Earth today.<ref>{{harvnb|Voet|Voet|2004|p=29}}</ref> It primarily uses tools from [[biology]], [[chemistry]], and [[geophysics]],<ref name="Dyson 1999">{{harvnb|Dyson|1999}}</ref> with more recent approaches attempting a synthesis of all three:<ref>{{cite book |author= Davies, Paul |date= 1998 |title= The Fifth Miracle, Search for the origin and meaning of life |publisher= Penguin}}{{page needed|date=February 2017}}</ref> more specifically, [[astrobiology]], [[biochemistry]], [[biophysics]], [[geochemistry]], [[molecular biology]], [[oceanography]] and [[paleontology]]. Life functions through the specialized chemistry of [[carbon]] and [[water]] and builds largely upon four key families of chemicals: [[lipids]] (cell membranes), [[carbohydrates]] (sugars, cellulose), [[amino acid]]s (protein metabolism), and [[nucleic acids]] (DNA and RNA). Any successful theory of abiogenesis must explain the origins and interactions of these classes of molecules.<ref>{{cite book |author1= Ward, Peter|author2= Kirschvink, Joe |date= 2015 |title= A New History of Life: the radical discoveries about the origins and evolution of life on earth |publisher= Bloomsbury Press |pages= 39–40 |isbn= 978-1608199105}}</ref> Many approaches to abiogenesis investigate how [[Self-replication|self-replicating]] [[molecule]]s, or their components, came into existence. Researchers generally think that current life descends from an [[RNA world]],<ref name="RNA" /> although other self-replicating molecules may have preceded RNA.<ref name="Robertson2012" /><ref name="Cech2012" /><br />
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The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today. It primarily uses tools from biology, chemistry, and geophysics, with more recent approaches attempting a synthesis of all three: more specifically, astrobiology, biochemistry, biophysics, geochemistry, molecular biology, oceanography and paleontology. Life functions through the specialized chemistry of carbon and water and builds largely upon four key families of chemicals: lipids (cell membranes), carbohydrates (sugars, cellulose), amino acids (protein metabolism), and nucleic acids (DNA and RNA). Any successful theory of abiogenesis must explain the origins and interactions of these classes of molecules. Many approaches to abiogenesis investigate how self-replicating molecules, or their components, came into existence. Researchers generally think that current life descends from an RNA world, although other self-replicating molecules may have preceded RNA.<br />
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对自然发生的研究旨在确定生命前的化学反应是如何在与今天地球上截然不同的条件下产生生命的。它主要使用生物学、化学和地球物理学的工具,最近的研究方法试图将这三者综合起来:更具体地说,就是天体生物学、生物化学、生物物理学、地球化学、分子生物学、海洋学和古生物学。生命的功能是通过碳和水的特定化学作用来实现的,并主要建立在四个关键的化学物质家族之上:脂类(细胞膜)、碳水化合物(糖类、纤维素)、氨基酸(蛋白质代谢)和核酸(DNA和RNA)。任何成功的自然发生理论都必须解释这些类别分子的起源和相互作用。许多自然发生的方法都在研究自我复制的分子或它们的组成部分是如何产生的。研究者普遍认为,目前的生命是从RNA世界中诞生的,尽管在RNA之前可能还有其他自我复制分子。<br />
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[[File:Miller-Urey experiment JP.png|thumb|'''Miller–Urey experiment''' Synthesis of small organic molecules in a mixture of simple gases that is placed in a thermal gradient by heating (left) and cooling (right) the mixture at the same time, a mixture that is also subject to electrical discharges]]<br />
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Miller–Urey experiment Synthesis of small organic molecules in a mixture of simple gases that is placed in a thermal gradient by heating (left) and cooling (right) the mixture at the same time, a mixture that is also subject to electrical discharges<br />
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米勒-乌雷Miller–Urey实验 在简单气体混合物中合成有机小分子,通过同时加热(左)和冷却(右)将混合物置于热梯度中,这种混合物也会受到放电的作用<br />
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The classic 1952 [[Miller–Urey experiment]] and similar research demonstrated that most amino acids, the chemical constituents of the [[protein]]s used in all living organisms, can be synthesized from [[inorganic compound]]s under conditions intended to replicate those of the [[History of Earth|early Earth]]. Scientists have proposed various external sources of energy that may have triggered these reactions, including [[lightning]] and [[radiation]]. Other approaches ("metabolism-first" hypotheses) focus on understanding how [[catalysis]] in chemical systems on the early Earth might have provided the [[Precursor (chemistry)|precursor molecules]] necessary for self-replication.<ref name="Ralser 2014">{{cite journal |last1= Keller |first1= Markus A. |last2= Turchyn |first2= Alexandra V. |last3= Ralser |first3= Markus |date= 25 March 2014 |title= Non‐enzymatic glycolysis and pentose phosphate pathway‐like reactions in a plausible Archean ocean |journal= [[Molecular Systems Biology]] |volume= 10 |issue= 725 |page= 725 |doi= 10.1002/msb.20145228 |pmc= 4023395 |pmid= 24771084}}</ref><br />
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The classic 1952 Miller–Urey experiment and similar research demonstrated that most amino acids, the chemical constituents of the proteins used in all living organisms, can be synthesized from inorganic compounds under conditions intended to replicate those of the early Earth. Scientists have proposed various external sources of energy that may have triggered these reactions, including lightning and radiation. Other approaches ("metabolism-first" hypotheses) focus on understanding how catalysis in chemical systems on the early Earth might have provided the precursor molecules necessary for self-replication.<br />
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1952年经典的Miller-Urey实验和类似的研究表明,大多数氨基酸,即所有生物体中使用的蛋白质的化学成分,可以在旨在复制早期地球的条件下从无机化合物中合成。科学家们提出了各种可能引发这些反应的外部能量来源,包括闪电和辐射。其他方法(“新陈代谢优先”假说)则侧重于了解早期地球化学系统中的催化作用如何提供自复制所需的前体分子。<br />
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The alternative [[panspermia hypothesis]]<ref name="USRA-2010">{{cite conference|last=Rampelotto|first=Pabulo Henrique|date=26 April 2010|title=Panspermia: A Promising Field of Research|url=http://www.lpi.usra.edu/meetings/abscicon2010/pdf/5224.pdf|url-status=live|conference=Astrobiology Science Conference 2010|location=Houston, TX|publisher=[[Lunar and Planetary Institute]]|page=5224|bibcode=2010LPICo1538.5224R|archiveurl=https://web.archive.org/web/20160327005016/http://www.lpi.usra.edu//meetings/abscicon2010/pdf/5224.pdf|archivedate=27 March 2016|accessdate=2014-12-03|conference-url=http://www.lpi.usra.edu/meetings/abscicon2010/}} Conference held at League City, TX</ref> speculates that [[Microorganism|microscopic life]] arose outside Earth by unknown mechanisms, and spread to the early Earth on [[space dust]]<ref name="ARX-20171106">{{cite journal |last= Berera |first= Arjun |title= Space dust collisions as a planetary escape mechanism |journal= Astrobiology |date= 6 November 2017 |arxiv= 1711.01895 |bibcode= 2017AsBio..17.1274B |doi= 10.1089/ast.2017.1662 |pmid= 29148823 |volume= 17 |issue= 12 |pages= 1274–1282|s2cid= 126012488 }}</ref> and [[meteoroid]]s.<ref name="SA-20180110">{{cite journal|last1=Chan|first1=Queenie H.S.|date=10 January 2018|title=Organic matter in extraterrestrial water-bearing salt crystals|journal=[[Science Advances]]|volume=4|page=eaao3521|bibcode=2018SciA....4O3521C|doi=10.1126/sciadv.aao3521|pmc=5770164|pmid=29349297|number=1, eaao3521}}</ref> It is known that complex [[List of interstellar and circumstellar molecules|organic molecules]] occur in the [[Solar System]] and in [[interstellar space]], and these molecules may have provided [[Precursor (chemistry)|starting material]] for the development of life on Earth.<ref name="Ehrenfreund2010" /><ref name="Science 2015">{{cite news|url=http://news.sciencemag.org/chemistry/2015/04/organic-molecules-found-circling-nearby-star?rss=1|title=Organic molecules found circling nearby star|last=Perkins|first=Sid|date=8 April 2015|work=[[Science (journal)|Science]]|accessdate=2015-06-02|publisher=[[American Association for the Advancement of Science]]|location=Washington, DC|type=News}}</ref><ref>{{cite news|url=http://www.rsc.org/chemistryworld/2015/04/meteorites-may-have-delivered-chemicals-started-life-earth|title=Chemicals formed on meteorites may have started life on Earth|last=King|first=Anthony|date=14 April 2015|work=[[Chemistry World]]|accessdate=2015-04-17|archiveurl=https://web.archive.org/web/20150417142723/http://www.rsc.org/chemistryworld/2015/04/meteorites-may-have-delivered-chemicals-started-life-earth|archivedate=17 April 2015|url-status=live|publisher=[[Royal Society of Chemistry]]|location=London|type=News}}</ref><ref>{{cite journal|last1=Saladino|first1=Raffaele|last2=Carota|first2=Eleonora|last3=Botta|first3=Giorgia|last4=Kapralov|first4=Mikhail|last5=Timoshenko|first5=Gennady N.|last6=Rozanov|first6=Alexei Y.|last7=Krasavin|first7=Eugene|last8=Di Mauro|first8=Ernesto|display-authors=3|date=13 April 2015|title=Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation|journal=[[Proceedings of the National Academy of Sciences of the United States of America|Proc. Natl. Acad. Sci. U.S.A.]]|volume=112|issue=21|pages=E2746–E2755|bibcode=2015PNAS..112E2746S|doi=10.1073/pnas.1422225112|pmc=4450408|pmid=25870268}}</ref><br />
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The alternative panspermia hypothesis speculates that microscopic life arose outside Earth by unknown mechanisms, and spread to the early Earth on space dust and meteoroids. It is known that complex organic molecules occur in the Solar System and in interstellar space, and these molecules may have provided starting material for the development of life on Earth.<br />
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另一种有生源论假说推测,微生物通过未知的机制在地球以外产生,并通过太空尘埃和流星体传播到早期地球。众所周知,太阳系和星际空间中存在复杂的有机分子,这些分子可能为地球上生命的发展提供了起始物质。<br />
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Earth remains the only place in the [[universe]] known to harbour life,<ref name="NASA-1990">{{cite web |url= https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900013148.pdf |title= Extraterrestrial Life in the Universe |last= Graham |first= Robert W. |date= February 1990 |place= [[Glenn Research Center|Lewis Research Center]], Cleveland, Ohio |publisher= [[NASA]] |type= NASA Technical Memorandum 102363 |accessdate= 2015-06-02 |url-status= live |archiveurl= https://web.archive.org/web/20140903100534/http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900013148.pdf |archivedate= 3 September 2014}}</ref><ref>{{harvnb|Altermann|2009|p=xvii}}</ref> and [[Earliest known life forms|fossil evidence from the Earth]] informs most studies of abiogenesis. The [[age of the Earth]] is 4.54 Gy (Giga or billion year);<ref name="USGS1997">{{cite web |url= http://pubs.usgs.gov/gip/geotime/age.html |title= Age of the Earth |date= 9 July 2007 |publisher= [[United States Geological Survey]] |accessdate= 2006-01-10 |url-status= live |archiveurl= https://web.archive.org/web/20051223072700/http://pubs.usgs.gov/gip/geotime/age.html |archivedate= 23 December 2005}}</ref><ref>{{harvnb|Dalrymple|2001|pp= 205–221}}</ref><ref>{{cite journal |last1= Manhesa |first1= Gérard |last2= Allègre |first2= Claude J. |authorlink2= Claude Allègre |last3= Dupréa |first3= Bernard |last4= Hamelin |first4= Bruno |date= May 1980 |title= Lead isotope study of basic-ultrabasic layered complexes: Speculations about the age of the earth and primitive mantle characteristics |journal= [[Earth and Planetary Science Letters]] |volume= 47 |issue= 3 |pages= 370–382 |bibcode= 1980E&PSL..47..370M |doi= 10.1016/0012-821X(80)90024-2 }}</ref> the earliest undisputed evidence of life on Earth dates from at least 3.5 Gya (Gy ago),<ref name="Origin1">{{cite journal |last1= Schopf |first1= J. William |authorlink1= J. William Schopf |last2= Kudryavtsev |first2= Anatoliy B. |last3= Czaja |first3= Andrew D. |last4= Tripathi |first4= Abhishek B. |date= 5 October 2007 |title= Evidence of Archean life: Stromatolites and microfossils |journal= [[Precambrian Research]] |volume= 158 |pages= 141–155 |issue= 3–4 |doi= 10.1016/j.precamres.2007.04.009 |bibcode= 2007PreR..158..141S }}</ref><ref name="Origin2">{{cite journal |last= Schopf |first= J. William |date= 29 June 2006 |title= Fossil evidence of Archaean life |journal= [[Philosophical Transactions of the Royal Society B]] |volume= 361 |issue= 1470 |pages= 869–885 |doi= 10.1098/rstb.2006.1834 |pmid= 16754604 |pmc=1578735}}</ref><ref name="RavenJohnson2002">{{harvnb|Raven|Johnson|2002|p=68}}</ref> and possibly as early as the [[Eoarchean]] Era (3.6-4.0 Gya). In 2017 scientists found possible evidence of early life [[Evolutionary history of life#Colonization of land|on land]] in 3.48 Gyo (Gy old) [[geyserite]] and other related mineral deposits (often found around [[hot spring]]s and [[geyser]]s) uncovered in the [[Pilbara Craton]] of [[Western Australia]].<ref name="PO-20170509">{{cite news |author= Staff |title= Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks |url= https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |date= 9 May 2017 |work= [[Phys.org]] |accessdate= 13 May 2017 |url-status= live |archiveurl= https://web.archive.org/web/20170510013721/https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |archivedate= 10 May 2017}}</ref><ref name="NC-20170509">{{cite journal |last1= Djokic |first1= Tara |last2= Van Kranendonk |first2= Martin J. |last3= Campbell |first3= Kathleen A. |last4= Walter |first4= Malcolm R. |last5= Ward |first5= Colin R. |title= Earliest signs of life on land preserved in ca. 3.5 Gao hot spring deposits |date= 9 May 2017 |journal= [[Nature Communications]] |doi= 10.1038/ncomms15263 |pmid= 28486437 |pmc= 5436104 |volume= 8 |page= 15263 |bibcode= 2017NatCo...815263D}}</ref><ref name="PNAS-2017">{{cite journal |last1= Schopf |first1= J. William |last2= Kitajima |first2= Kouki |last3= Spicuzza |first3= Michael J. |last4= Kudryavtsev |first4= Anatolly B. |last5= Valley |first5= John W. |title= SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions |date= 2017 |journal= [[Proceedings of the National Academy of Sciences of the United States of America|PNAS]] |doi= 10.1073/pnas.1718063115 |pmid= 29255053 |pmc= 5776830 |volume= 115 |issue= 1 |pages= 53–58|bibcode= 2018PNAS..115...53S }}</ref><ref name="WU-20171218">{{cite web |last= Tyrell |first= Kelly April |title= Oldest fossils ever found show life on Earth began before 3.5 billion years ago |url= https://news.wisc.edu/oldest-fossils-ever-found-show-life-on-earth-began-before-3-5-billion-years-ago/ |date= 18 December 2017 |work= [[University of Wisconsin-Madison]] |accessdate= 18 December 2017 }}</ref> However, a number of discoveries suggest that life may have appeared on Earth even earlier. {{As of | 2017}}, [[Micropaleontology#Microfossils|microfossils]] (fossilised [[microorganism]]s) within [[Hydrothermal vent|hydrothermal-vent precipitates]] dated 3.77 to 4.28 Gya in rocks in [[Quebec]] may harbour the oldest record of life on Earth, suggesting life started soon after [[Origin of water on Earth#Water in the development of Earth|ocean formation 4.4 Gya]] during the [[Hadean]] [[Geologic time scale|Eon]].<ref name="NAT-20170301">{{cite journal |last1= Dodd |first1= Matthew S. |last2= Papineau |first2= Dominic |last3= Grenne |first3= Tor |last4= Slack |first4= John F. |last5= Rittner |first5= Martin |last6= Pirajno |first6= Franco |last7= O'Neil |first7= Jonathan |last8= Little |first8= Crispin T.S. |title= Evidence for early life in Earth's oldest hydrothermal vent precipitates |url= http://eprints.whiterose.ac.uk/112179/ |journal= [[Nature (journal)|Nature]] |date= 1 March 2017 |volume= 543 |issue= 7643 |pages= 60–64 |doi= 10.1038/nature21377 |pmid= 28252057 |accessdate= 2 March 2017 |bibcode= 2017Natur.543...60D |url-status= live |archiveurl= https://web.archive.org/web/20170908201821/http://eprints.whiterose.ac.uk/112179/ |archivedate= 8 September 2017|doi-access= free }}</ref><ref name="NYT-20170301">{{cite news |last= Zimmer |first= Carl |authorlink= Carl Zimmer |title= Scientists Say Canadian Bacteria Fossils May Be Earth's Oldest |url= https://www.nytimes.com/2017/03/01/science/earths-oldest-bacteria-fossils.html |date= 1 March 2017 |work= [[The New York Times]] |accessdate= 2 March 2017 |url-status= live |archiveurl= https://web.archive.org/web/20170302042424/https://www.nytimes.com/2017/03/01/science/earths-oldest-bacteria-fossils.html |archivedate= 2 March 2017}}</ref><ref name="BBC-20170301">{{Cite news |last= Ghosh |first= Pallab |title= Earliest evidence of life on Earth found |url= https://www.bbc.co.uk/news/science-environment-39117523 |publisher= [[BBC News]] |date= 1 March 2017 |accessdate= 2 March 2017 |url-status= live |archiveurl= https://web.archive.org/web/20170302002134/http://www.bbc.co.uk/news/science-environment-39117523 |archivedate= 2 March 2017|work= BBC News }}</ref><ref name="4.3b oldest">{{cite news |last1= Dunham |first1= Will |title= Canadian bacteria-like fossils called oldest evidence of life |url= http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |date= 1 March 2017 |agency= [[Reuters]] |accessdate= 1 March 2017 |url-status= live |archiveurl= https://web.archive.org/web/20170302114728/http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |archivedate= 2 March 2017}}</ref><ref>{{cite news|title=Researchers uncover 'direct evidence' of life on Earth 4 billion years ago|url= http://dw.com/p/2YUnT|accessdate= 5 March 2017|publisher= Deutsche Welle}}</ref><br />
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Earth remains the only place in the universe known to harbour life, and fossil evidence from the Earth informs most studies of abiogenesis. The age of the Earth is 4.54 Gy (Giga or billion year); the earliest undisputed evidence of life on Earth dates from at least 3.5 Gya (Gy ago), and possibly as early as the Eoarchean Era (3.6-4.0 Gya). In 2017 scientists found possible evidence of early life on land in 3.48 Gyo (Gy old) geyserite and other related mineral deposits (often found around hot springs and geysers) uncovered in the Pilbara Craton of Western Australia. However, a number of discoveries suggest that life may have appeared on Earth even earlier. As of 2017, microfossils (fossilised microorganisms) within hydrothermal-vent precipitates dated 3.77 to 4.28 Gya in rocks in Quebec may harbour the oldest record of life on Earth, suggesting life started soon after ocean formation 4.4 Gya during the Hadean Eon.<br />
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地球仍然是宇宙中已知的唯一一个孕育生命的地方,来自地球的化石证据为大多数关于自然发生论的研究提供了信息。地球的年龄是45.5亿年;地球上最早的无可争议的生命证据至少可以追溯到35亿年前,也可能还要追溯到早至始太古代(36-40亿年前之间)。2017年,科学家在西澳大利亚的皮尔巴拉古地台发现的34.8亿岁的硅华和其他相关矿藏(通常在温泉和间歇泉附近发现) 中发现了陆地上早期生命的可能证据。然而,许多发现表明,地球上的生命可能出现得更早。截至2017年,加拿大魁北克省的岩石中37.7亿至42.8亿年前的深海热液喷口沉淀物内的微化石(化石微生物)可能蕴藏着地球上最古老的生命记录,这表明生命在冥古宙44亿年前海洋形成后不久就开始了。<br />
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The NASA strategy on abiogenesis states that it is necessary to identify interactions, intermediary structures and functions, energy sources, and environmental factors that contributed to the diversity, selection, and replication of evolvable macromolecular systems.<ref name="NASA strategy 2015">{{cite web|url=https://nai.nasa.gov/media/medialibrary/2015/10/NASA_Astrobiology_Strategy_2015_151008.pdf|title=NASA Astrobiology Strategy|year=2015|work=NASA|url-status=dead|archiveurl=https://web.archive.org/web/20161222190306/https://nai.nasa.gov/media/medialibrary/2015/10/NASA_Astrobiology_Strategy_2015_151008.pdf|archivedate=22 December 2016|access-date=24 September 2017}}</ref> Emphasis must continue to map the chemical landscape of potential primordial informational [[polymers]]. The advent of polymers that could replicate, store genetic information, and exhibit properties subject to selection likely was a critical step in the [[emergence]] of prebiotic chemical evolution.<ref name="NASA strategy 2015"/><br />
<br />
The NASA strategy on abiogenesis states that it is necessary to identify interactions, intermediary structures and functions, energy sources, and environmental factors that contributed to the diversity, selection, and replication of evolvable macromolecular systems. Emphasis must continue to map the chemical landscape of potential primordial informational polymers. The advent of polymers that could replicate, store genetic information, and exhibit properties subject to selection likely was a critical step in the emergence of prebiotic chemical evolution.<br />
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美国宇航局关于自然发生的战略指出,有必要确定相互作用、中间结构和功能、能量来源和环境因素,这些因素有助于可进化大分子系统的多样性、选择和复制的因素。强调必须继续绘制潜在的原始信息聚合物的化学景观。能够复制、储存遗传信息并表现出受选择的特性的聚合物的出现,很可能是生命起源前化学进化涌现的关键一步。<br />
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<br />
== Thermodynamics, self-organization, and information: Physics ==<br />
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热力学、自组织和信息:物理<br />
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===Thermodynamics principles: Energy and entropy===<br />
热力学原理:能量与熵<br />
<br />
In antiquity it was commonly thought, for instance by Empedocles and Aristotle, that the life of the individuals of some species, and more generally, life itself, could start with high temperature, i.e. implicitly by thermal cycling.<ref>{{cite book|title=In the beginning: Some Greek views on the origins of life and the early state of man |year= 1957|last1= Guthrie|first1= W. K. C.|publisher=Methuen, London}}</ref><br />
<br />
In antiquity it was commonly thought, for instance by Empedocles and Aristotle, that the life of the individuals of some species, and more generally, life itself, could start with high temperature, i.e. implicitly by thermal cycling.<br />
<br />
在古代,人们普遍认为,例如恩培多克勒Empedocles和亚里士多德 Aristotle就认为,某些物种个体的生命,更一般地说是生命本身,可以从高温开始,即隐含着热循环。<br />
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Similarly, it was realized early on that life requires a loss of [[entropy]], or disorder, when molecules organize themselves into living matter. This [[Second law of thermodynamics|Second Law of thermodynamics]] needs to be considered when self-organization of matter to higher complexity happens. Because living organisms are machines,<ref>{{cite book| last1 = Simon| first1 = Michael A. | year = 1971| title = The Matter of Life | edition = 1| location = New Haven and London| publisher = Yale University Press}}</ref> the Second Law applies to life as well.<br />
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Similarly, it was realized early on that life requires a loss of entropy, or disorder, when molecules organize themselves into living matter. This Second Law of thermodynamics needs to be considered when self-organization of matter to higher complexity happens. Because living organisms are machines, the Second Law applies to life as well.<br />
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同样,人们很早就意识到,当分子将自身组织成生命物质时,生命需要失去熵,或无序。当物质自组织到更高的复杂性时,需要考虑热力学第二定律。因为生物体是机器,第二定律也适用于生命。<br />
<br />
====Obtaining free energy ====<br />
获得自由能<br />
Bernal said on the Miller–Urey experiment that < blockquote >it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.<ref>{{harvnb|Bernal|1967|p=143}}</ref><br />
< /blockquote ><br />
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Bernal said on the Miller–Urey experiment that < blockquote >it is not enough to explain the formation of such molecules, what is necessary, is a physical-chemical explanation of the origins of these molecules that suggests the presence of suitable sources and sinks for free energy.< /blockquote ><br />
伯纳尔Bernal在 Miller-Urey 的实验中说,<br />
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< blockquote >仅仅解释这些分子的形成是不够的,需要的是对这些分子的起源作出物理-化学解释,表明存在合适的自由能源和自由能汇。<br />
</blockquote ><br />
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Multiple sources of energy were available for chemical reactions on the early Earth. For example, heat (such as from [[geothermal energy|geothermal]] processes) is a standard energy source for chemistry. Other examples include sunlight and electrical discharges (lightning), among others.<ref name="Follmann2009" /> In fact, lightning is a plausible energy source for the origin of life, given that just in the tropics lightning strikes about 100 million times a year.<ref>{{Cite journal|last1=Gora|first1=Evan M.|last2=Burchfield|first2=Jeffrey C.|last3=Muller‐Landau|first3=Helene C.|last4=Bitzer|first4=Phillip M.|last5=Yanoviak|first5=Stephen P.|title=Pantropical geography of lightning-caused disturbance and its implications for tropical forests|journal=Global Change Biology|year=2020|language=en|volume=n/a|issue=n/a|pages=5017–5026|doi=10.1111/gcb.15227|pmid=32564481|bibcode=2020GCBio..26.5017G|issn=1365-2486}}</ref><br />
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Multiple sources of energy were available for chemical reactions on the early Earth. For example, heat (such as from geothermal processes) is a standard energy source for chemistry. Other examples include sunlight and electrical discharges (lightning), among others. In fact, lightning is a plausible energy source for the origin of life, given that just in the tropics lightning strikes about 100 million times a year.<br />
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早期地球上的化学反应有多种能量来源。例如,热(如来自地热过程)是化学的标准能源。其他的例子还包括阳光和放电(闪电)等。事实上,闪电是生命起源的似乎合理的能量来源,因为仅在热带地区,每年就有大约1亿次的闪电袭击。<br />
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Computer simulations also suggest that [[cavitation]] in primordial water reservoirs such as breaking sea waves, streams and oceans can potentially lead to the synthesis of biogenic compounds.<ref>{{cite journal|doi=10.1021/acscentsci.7b00325|pmid= 28979946|pmc= 5620973|title= Cavitation-Induced Synthesis of Biogenic Molecules on Primordial Earth|journal= ACS Central Science|volume= 3|issue= 9|pages= 1041–1049|year= 2017|last1= Kalson|first1= Natan-Haim|last2= Furman|first2= David|last3= Zeiri|first3= Yehuda}}</ref><br />
<br />
Computer simulations also suggest that cavitation in primordial water reservoirs such as breaking sea waves, streams and oceans can potentially lead to the synthesis of biogenic compounds.<br />
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计算机模拟还表明,原始水库中的气蚀作用,如破碎的海浪、溪流和海洋,有可能导致生源化合物的合成。<br />
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Unfavourable reactions can also be driven by highly favourable ones, as in the case of iron-sulfur chemistry. For example, this was probably important for [[carbon fixation]] (the conversion of carbon from its inorganic form to an organic one). Carbon fixation via iron-sulfur chemistry is highly favourable, and occurs at neutral pH and 100C. Iron-sulfur surfaces, which are abundant near hydrothermal vents, are also capable of producing small amounts of amino acids and other biological metabolites.<br />
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Unfavourable reactions can also be driven by highly favourable ones, as in the case of iron-sulfur chemistry. For example, this was probably important for carbon fixation (the conversion of carbon from its inorganic form to an organic one). Carbon fixation via iron-sulfur chemistry is highly favourable, and occurs at neutral pH and 100C. Iron-sulfur surfaces, which are abundant near hydrothermal vents, are also capable of producing small amounts of amino acids and other biological metabolites.<br />
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不利的反应也可以由非常有利的反应驱动,如铁硫化学反应。例如,这对碳固定(碳从其无机形式转化为有机形式)可能很重要。通过铁硫化学反应进行的碳固定是非常有利的,在中性pH值和100C时发生。深海热液喷口附近丰富的铁硫表面也能产生少量的氨基酸和其他生物代谢物。<br />
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===Self-organization===<br />
自组织<br />
[[File:Hermann Haken, Pour le Merite 2014.jpg|thumb|upright|Hermann Haken]]<br />
赫尔曼•哈肯Hermann Haken<br />
The discipline of synergetics studies self-organization in physical systems. In his book ''[[Synergetics (Haken)|Synergetics]]''<ref>{{cite book |last1 = Haken| first1= Hermann | title=Synergetics. An Introduction. |year=1978 | publisher=Springer | location= Berlin }}</ref> [[Hermann Haken]] has pointed out that different physical systems can be treated in a similar way. He gives as examples of self-organization several types of lasers, instabilities in fluid dynamics, including convection, and chemical and biochemical oscillations. In his preface he mentions the origin of life, but only in general terms:<br />
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The discipline of synergetics studies self-organization in physical systems. In his book Synergetics Hermann Haken has pointed out that different physical systems can be treated in a similar way. He gives as examples of self-organization several types of lasers, instabilities in fluid dynamics, including convection, and chemical and biochemical oscillations. In his preface he mentions the origin of life, but only in general terms:<br />
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协同学这门学科研究的是物理系统的自组织。Hermann Haken在其《协同论》一书中指出,不同的物理系统可以用类似的方式处理。他举了几种类型的激光、流体动力学(包括对流)中的不稳定性以及化学和生化振荡作为自组织的例子。在他的序言中他提到了生命的起源,但只是泛泛而谈。<br />
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< blockquote ><br />
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The spontaneous formation of well organized structures out of germs or even out of chaos is one of the most fascinating phenomena and most challenging problems scientists are confronted with. Such phenomena are an experience of our daily life when we observe the growth of plants and animals. Thinking of much larger time scales, scientists are led into the problems of evolution, and, ultimately, of the origin of living matter. When we try to explain or understand in some sense these extremely complex biological phenomena it is a natural question, whether processes of self-organization may be found in much simpler systems of the unanimated world.<br />
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从细菌甚至从混沌中自发形成的组织良好的结构是科学家们面临的最迷人的现象和最具挑战性的问题之一。这种现象是我们在日常生活中观察动植物生长时的一种体验。从更大的时间尺度来思考,科学家们就会被引向进化问题,并最终引向生命物质的起源问题。当我们试图在某种意义上解释或理解这些极其复杂的生物现象时,这是一个很自然的问题,自组织的过程是否可以在无生命世界里简单得多的系统中找到。<br />
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<br />
< /blockquote ><br />
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< blockquote ><br />
In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are ''selforganizing''. ...<ref>{{cite book |last1 = Haken| first1= Hermann | title=Synergetics. An Introduction. |year=1978 | publisher=Springer }}</ref><br />
< /blockquote ><br />
<br />
< /blockquote ><br />
<br />
In recent years it has become more and more evident that there exists numerous examples in physical and chemical systems where well organized spatial, temporal, or spatio-temporal structures arise out of chaotic states. Furthermore, as in living organisms, the functioning of these systems can be maintained only by a flux of energy (and matter) through them. In contrast to man-made machines, which are devised to exhibit special structures and functionings, these structures develop spontaneously—they are selforganizing. ...<br />
<br />
近年来,越来越明显的是,在物理和化学系统中存在着许多例子,在这些例子中,从混沌状态中产生了组织良好的空间、时间或时空结构。此外,就像在生物体中一样,这些系统的功能只能通过流通它们的能量(和物质)流来维持。与人造机器不同的是,人造机器被设计成表现出特殊的结构和功能,这些结构是自发发展的——它们是自组织的...<br />
</blockquote ><br />
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<br />
====Multiple dissipative structures====<br />
多重耗散结构<br />
<br />
This theory postulates that the hallmark of the origin and evolution of life is the microscopic dissipative structuring of [[Biological pigment|organic pigments]] and their proliferation over the entire Earth surface.<ref name="Michaelian, K. 2017" /> Present day life augments the entropy production of Earth in its solar environment by dissipating [[ultraviolet]] and [[Visible spectrum|visible]] [[photon]]s into heat through organic pigments in water. This heat then catalyzes a host of secondary dissipative processes such as the [[water cycle]], [[Ocean current|ocean]] and [[wind]] currents, [[Tropical cyclone|hurricanes]], etc.<ref name="Michaelian, K. 2011"/><ref name="HESS Opinions 'Biological catalysis">{{cite journal |doi=10.5194/hess-16-2629-2012 |title=HESS Opinions 'Biological catalysis of the hydrological cycle: Life's thermodynamic function' |journal=Hydrology and Earth System Sciences |volume=16 |issue=8 |pages=2629–2645 |year=2012 |last1=Michaelian |first1=K |bibcode=2012HESS...16.2629M |arxiv= 0907.0040 }}</ref><br />
<br />
This theory postulates that the hallmark of the origin and evolution of life is the microscopic dissipative structuring of organic pigments and their proliferation over the entire Earth surface. Present day life augments the entropy production of Earth in its solar environment by dissipating ultraviolet and visible photons into heat through organic pigments in water. This heat then catalyzes a host of secondary dissipative processes such as the water cycle, ocean and wind currents, hurricanes, etc.<br />
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该理论假设生命起源和进化的标志是有机色素的微观耗散结构及其在整个地球表面的扩散。现今的生命通过将紫外线和可见光子通过水中的有机色素耗散成热能,从而增加了地球在太阳环境中的熵产生。然后这些热量又催化了一系列的二次耗散过程,如水循环、洋流和风流、飓风等。<br />
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==== Selforganization by dissipative structures====<br />
耗散结构的自组织<br />
<br />
[[File:Ilya Prigogine 1977c.jpg|thumb|upright|Ilya Prigogine 1977c]]<br />
<br />
伊利亚·普里戈金Ilya Prigogine 1977c<br />
<br />
The 19th-century physicist [[Ludwig Boltzmann]] first recognized that the struggle for existence of living organisms was neither over raw material nor [[energy]], but instead had to do with [[entropy production]] derived from the conversion of the solar [[spectrum]] into [[heat]] by these systems.<ref>Boltzmann, L. (1886) The Second Law of Thermodynamics, in: Ludwig Boltzmann: Theoretical physics and Selected writings, edited by: McGinness, B., D. Reidel, Dordrecht, The Netherlands, 1974.</ref> Boltzmann thus realized that living systems, like all [[Reversible process (thermodynamics)|irreversible processes]], were dependent on the [[dissipation]] of a generalized chemical potential for their existence. In his book "What is Life", the 20th-century physicist [[Erwin Schrödinger]]<ref>Schrödinger, Erwin (1944) What is Life? The Physical Aspect of the Living Cell. Cambridge University Press</ref> emphasized the importance of Boltzmann's deep insight into the irreversible thermodynamic nature of living systems, suggesting that this was the physics and chemistry behind the origin and evolution of life.<br />
<br />
The 19th-century physicist Ludwig Boltzmann first recognized that the struggle for existence of living organisms was neither over raw material nor energy, but instead had to do with entropy production derived from the conversion of the solar spectrum into heat by these systems. Boltzmann thus realized that living systems, like all irreversible processes, were dependent on the dissipation of a generalized chemical potential for their existence. In his book "What is Life", the 20th-century physicist Erwin Schrödinger emphasized the importance of Boltzmann's deep insight into the irreversible thermodynamic nature of living systems, suggesting that this was the physics and chemistry behind the origin and evolution of life.<br />
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19世纪的物理学家路德维希-玻尔兹曼Ludwig Boltzmann首先认识到,生物体的生存斗争既不是为了原料,也不是为了能源,而是与这些系统将太阳光谱转化为热能所产生的熵有关。Boltzmann由此认识到,生命系统和所有不可逆的过程一样,其存在依赖于广义化学势的耗散。20世纪物理学家埃尔温·薛定谔 Erwin Schrödinger在其《生命是什么》一书中强调了Boltzmann对生命系统不可逆的热力学本质的深刻洞察,认为这就是生命起源和进化背后的物理学和化学。<br />
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However, irreversible processes, and much less living systems, could not be conveniently analyzed under this perspective until [[Lars Onsager]],<ref>Onsager, L. (1931) Reciprocal Relations in Irreversible Processes I and II, ''Phys. Rev.'' 37, 405; 38, 2265 (1931)</ref> and later Ilya [[Ilya Prigogine|Prigogine]],<ref>Prigogine, I. (1967) An Introduction to the Thermodynamics of Irreversible Processes, Wiley, New York</ref> developed an elegant mathematical formalism for treating the "self-organization" of material under a generalized chemical potential. This formalism became known as Classical Irreversible Thermodynamics and Prigogine was awarded the [[Nobel Prize in Chemistry]] in 1977 "for his contributions to [[non-equilibrium thermodynamics]], particularly the theory of [[Dissipative system|dissipative structures]]". The analysis by Prigogine showed that if a [[system]] were left to evolve under an imposed external potential, material could spontaneously organize (lower its [[entropy]]) forming what he called "dissipative structures" which would increase the dissipation of the externally imposed potential (augment the global entropy production). Non-equilibrium thermodynamics has since been successfully applied to the analysis of living systems, from the biochemical production of [[Adenosine triphosphate|ATP]]<ref>{{cite journal | last1 = Dewar | first1 = R | last2 = Juretić | first2 = D. | last3 = Županović | first3 = P. | year = 2006 | title = The functional design of the rotary enzyme ATP synthase is consistent with maximum entropy production | journal = Chem. Phys. Lett. | volume = 430 | issue = 1| pages = 177–182 | doi=10.1016/j.cplett.2006.08.095| bibcode = 2006CPL...430..177D }}</ref> to optimizing bacterial metabolic pathways<ref>Unrean, P., Srienc, F. (2011) Metabolic networks evolve towards states of maximum entropy production, Metabolic Engineering 13, 666–673.</ref> to complete ecosystems.<ref>Zotin, A.I. (1984) "Bioenergetic trends of evolutionary progress of organisms", in: ''Thermodynamics and regulation of biological processes'' Lamprecht, I. and Zotin, A.I. (eds.), De Gruyter, Berlin, pp. 451–458.</ref><ref>{{cite journal | last1 = Schneider | first1 = E.D. | last2 = Kay | first2 = J.J. | year = 1994 | title = Life as a Manifestation of the Second Law of Thermodynamics | journal = Mathematical and Computer Modelling | volume = 19 | issue = 6–8| pages = 25–48 | doi=10.1016/0895-7177(94)90188-0| citeseerx = 10.1.1.36.8381 }}</ref><ref>{{cite journal | last1 = Michaelian | first1 = K. | year = 2005 | title = Thermodynamic stability of ecosystems | journal = Journal of Theoretical Biology | volume = 237 | issue = 3| pages = 323–335 | bibcode = 2004APS..MAR.P9015M | doi=10.1016/j.jtbi.2005.04.019| pmid = 15978624 }}</ref><br />
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However, irreversible processes, and much less living systems, could not be conveniently analyzed under this perspective until Lars Onsager, and later Ilya Prigogine, developed an elegant mathematical formalism for treating the "self-organization" of material under a generalized chemical potential. This formalism became known as Classical Irreversible Thermodynamics and Prigogine was awarded the Nobel Prize in Chemistry in 1977 "for his contributions to non-equilibrium thermodynamics, particularly the theory of dissipative structures". The analysis by Prigogine showed that if a system were left to evolve under an imposed external potential, material could spontaneously organize (lower its entropy) forming what he called "dissipative structures" which would increase the dissipation of the externally imposed potential (augment the global entropy production). Non-equilibrium thermodynamics has since been successfully applied to the analysis of living systems, from the biochemical production of ATP to optimizing bacterial metabolic pathways to complete ecosystems.<br />
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然而,不可逆的过程,更不用说生命系统了,在这个角度下无法方便地进行分析,直到拉斯·昂萨格 Lars Onsager和后来的Ilya Prigogine,发展了一种优雅的数学形式体系,用于处理广义化学势下物质的 "自组织"。这个形式体系后来被称为经典不可逆热动力学,1977年Prigogine被授予诺贝尔化学奖,"以表彰他对非平衡热动力学,特别是耗散结构理论的贡献"。Prigogine的分析表明,如果让一个系统在一个强加的外部势下演化,物质可以自发地组织起来(降低其熵),形成他所说的 "耗散结构",从而增加外部强加势的耗散(增强全局熵的产生)。此后,非平衡热动力学被成功地应用于生命系统的分析,从ATP的生化生产到优化细菌代谢通路以形成完整的生态系统。<br />
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==当前的生命,生物发生的结果:生物学 Current life, the result of abiogenesis: biology==<br />
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===生命的定义 Definition of life===<br />
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When discussing the origin of life, a definition of life itself is fundamental. The definition is somewhat disagreed upon (although follows the same basic principles) because different biology textbooks define life differently. James Gould:<br />
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When discussing the origin of life, a definition of life itself is fundamental. The definition is somewhat disagreed upon (although follows the same basic principles) because different biology textbooks define life differently. James Gould:<br />
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当讨论生命的起源时,最基本的问题是对生命本身的定义。由于不同的生物学教科书对生命的定义不同,所以这个定义存在一定的分歧(虽然遵循相同的基本原则)。詹姆斯·古尔德 James Gould :<br />
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<blockquote><br />
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Most dictionaries define ''life'' as the property that distinguishes the living from the dead, and define ''dead'' as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants. <ref name="Gould">{{cite book| last1 = Gould | first1 = James L. | last2 = Keeton | first2 = William T. | year = 1996| edition = 6 | title = Biological Science | location= New York | publisher = W.W. Norton }}</ref><br />
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Most dictionaries define life as the property that distinguishes the living from the dead, and define dead as being deprived of life. These singularly circular and unsatisfactory definitions give us no clue to what we have in common with protozoans and plants.<br />
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大多数字典将生命定义为区别于存活和死亡的属性,并将死亡定义为被剥夺了生命。这些奇怪循环的、难以令人满意的定义,没有给我们提供任何线索,使我们了解我们与原生动物和植物的共同之处。<ref name="Gould">{{cite book| last1 = Gould | first1 = James L. | last2 = Keeton | first2 = William T. | year = 1996| edition = 6 | title = Biological Science | location= New York | publisher = W.W. Norton }}</ref><br />
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</blockquote><br />
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whereas according to Neil Campbell and Jane Reece < blockquote >The phenomenon we call life defies a simple, one-sentence definition.<ref “Campbell”>{{cite book| last1 = Campbell | first1 = Neil A. | last2 = Reece | first2 = Jane B.| year = 2005| edition = 7 | title = Biology | location= Sn Feancisco | publisher = Benjamin }}</ref>< /blockquote ><br />
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whereas according to Neil Campbell and Jane Reece < blockquote >The phenomenon we call life defies a simple, one-sentence definition.<br />
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然而,根据尼尔·坎贝尔Neil Campbell和简·里斯Jane Reece 的说法,<br />
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<blockquote><br />
The phenomenon we call life defies a simple, one-sentence definition.<br />
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我们称之为生命的现象,不能用简单的一句话去定义。<br />
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</blockquote><br />
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This difference can also be found in books on the origin of life. John Casti gives a single sentence:<br />
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在关于生命起源的书籍中也可以找到这种差异。约翰·卡斯蒂John Casti给出了一句话:<br />
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<blockquote><br />
By more or general consensus nowadays, an entity is considered to be "alive" if it has the capacity to carry out three basic functional activities: metabolism, self-repair, and replication.<br />
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现在越来越多的人或普遍认为,如果一个实体有能力进行三种基本的功能活动:新陈代谢、自我修复,和复制,那么它就被认为是“有生命的”。<br />
</blockquote> <br />
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Dirk Schulze-Makuch and Louis Irwin spend in contrast the whole first chapter of their book on this subject.<br />
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相比之下,德克·舒尔茨-马库奇Dirk Schulze-Makuch 和 路易斯·欧文 Louis Irwin 在他们的书中花了整整第一章来讨论这个问题。<br />
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====发酵 Fermentation====<br />
发酵<br />
[[File:Citric acid cycle.svg|thumb|upright=1.5|left|Citric acid cycle]]<br />
柠檬酸循环<br />
[[File:Metabolism diagram.svg|thumb|Overall diagram of the chemical reactions of metabolism, in which the citric acid cycle can be recognized as the circle just below the middle of the figure 代谢化学反应的整体图,其中柠檬酸循环可以认为是位于图中间下方的圆圈]] [[Albert L. Lehninger|Albert Lehninger]] has stated around 1970 that fermentation, including glycolysis, is a suitable primitive energy source for the origin of life.<ref name="Lehninger">{{cite book| last1 = Lehninger | first1 = Albert L. | year = 1970| title = Biochemistry. The Molecular Basis of Cell Structure and Function | location= New York | publisher = Worth | page = 313}}</ref><br />
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Albert Lehninger has stated around 1970 that fermentation, including glycolysis, is a suitable primitive energy source for the origin of life.<br />
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阿尔伯特·莱宁格Albert Lehninger曾在1970年左右指出,包括糖酵解在内的发酵过程是生命起源一种合适的原始能量来源。<br />
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<blockquote> <br />
Since living organisms probably first arose in an atmosphere lacking oxygen, anaerobic fermentation is the simplest and most primitive type of biological mechanism for obtaining energy from nutrient molecules. <br />
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由于生物体可能首先是在缺氧的环境中产生的,因此无氧发酵是从营养分子中获取能量的一种最简单、最原始的生物机制。 <br />
</blockquote><br />
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Fermentation involves glycolysis, which, rather inefficiently, transduces the chemical energy of sugar into the chemical energy of ATP.<br />
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发酵过程包括糖酵解,它非常低效地将糖的化学能转化为ATP的化学能。<br />
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====化学渗透 Chemiosmosis====<br />
化学渗透<br />
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[[File:Oxiphos.png|thumb|left|upright=1.25|Oxidative phosphorylation]]<br />
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氧化磷酸化<br />
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[[File:Chemiosmotic coupling mitochondrion.gif|thumb|left|upright=1.25|Chemiosmotic coupling mitochondrion]]<br />
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化学渗透耦合线粒体<br />
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As Fermentation had around 1970 been elucidated, whereas the mechanism of oxidative phosphorylation had not and some controversies still existed, fermentation may have looked too complex for investigators of the origin of life at that time. Peter Mitchell's Chemiosmosis is now however generally accepted as correct.<br />
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由于在1970年左右发酵已经被阐明,而氧化磷酸化的机制还没有,而且存在一些争议,所以发酵作用在当时对生命起源的研究者来说可能显得过于复杂。不过,彼得·米切尔Peter Mitchell 的化学渗透现在被普遍接受是正确的。<br />
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Even Peter Mitchell himself assumed that fermentation preceded chemiosmosis. Chemiosmosis is however ubiquitous in life. A model for the origin of life has been presented in terms of chemiosmosis.<br />
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连Peter Mitchell自己也认为发酵先于化学渗透。然而,化学渗透在生命中无处不在。一个依据化学渗透的生命起源模型已经被提出来了。<br />
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Both respiration by mitochondria and photosynthesis in chloroplasts make use of chemiosmosis to generate most of their ATP.<br />
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线粒体的呼吸作用和叶绿体的光合作用都是利用化学渗透来产生大部分ATP。<br />
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Today the energy source of all life can be linked to photosynthesis, and one speaks of primary production by sunlight. The oxygen used for oxidizing reducing compounds by organisms at hydrothermal vents at the bottom of the ocean is the result of photosynthesis at the Oceans' surface.<br />
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今天,一切生命的能量来源都可以与光合作用联系起来,人们称之为太阳光的初级生产。海洋底部热液喷口中的生物用于氧化还原性化合物的氧气,就来源于海洋表面光合作用。<br />
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=====ATP合成酶 ATP synthase=====<br />
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[[File:ATP-Synthase.svg|thumb|upright|left|Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP synthesis through [[oxidative phosphorylation]].]]<br />
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Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP synthesis through [[oxidative phosphorylation.]]<br />
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用化学渗透质子梯度描述ATP合成酶,通过氧化磷酸化为ATP合成供能。<br />
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[[File:Paul D. Boyer.jpg|thumb|upright|Paul Boyer]]<br />
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保罗·博耶Paul D. Boyer<br />
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The mechanism of ATP synthesis is complex and involves a closed membrane in which the ATP synthase is embedded. The ATP is synthesized by the F1 subunit of ATP synthase by the binding change mechanism discovered by Paul Boyer. The energy required to release formed strongly-bound ATP has its origin in protons that move across the membrane. These protons have been set across the membrane during respiration or photosynthesis.<br />
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ATP的合成机制很复杂,涉及到ATP合成酶所嵌入的闭合膜。ATP是由ATP合成酶的F1亚基通过 Paul Boyer 发现的结合变化机制合成的。释放形成的牢固结合的ATP所需的能量源自跨膜移动的质子。这些质子在呼吸作用或光合作用过程中穿过膜。<br />
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====RNA世界 RNA world====<br />
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[[File:010 small subunit-1FKA.gif|thumb|upright=1.25|Molecular structure of the [[30S|ribosome 30S subunit]] from ''[[Thermus thermophilus]]''. 嗜热细菌核糖体30S亚基的分子结构。蛋白质显示为蓝色,单个RNA链显示为橙色。 <ref name="Venki">{{cite journal |last1=Wimberly |first1=Brian T. |last2=Brodersen |first2=Ditlev E. |last3=Clemons |first3=William M. Jr. |last4=Morgan-Warren |first4=Robert J. |last5=Carter |first5=Andrew P. |last6=Vonrhein |first6=Clemens |last7=Hartsch |first7=Thomas |last8=Ramakrishnan |first8=V. |authorlink8=Venkatraman Ramakrishnan |display-authors=3 |date=21 September 2000 |title=Structure of the 30S ribosomal subunit |journal=Nature |volume=407 |issue=6802 |pages=327–339 |doi=10.1038/35030006 |pmid=11014182|bibcode=2000Natur.407..327W |s2cid=4419944 }}</ref> [[Protein]]s are shown in blue and the single [[RNA]] chain in orange.]]<br />
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The [[RNA world]] hypothesis describes an early Earth with self-replicating and catalytic RNA but no DNA or proteins.<ref name="NYT-20140925-CZ">{{cite news |last=Zimmer |first=Carl |date=25 September 2014 |title=A Tiny Emissary From the Ancient Past |url=https://www.nytimes.com/2014/09/25/science/a-tiny-emissary-from-the-ancient-past.html |newspaper=The New York Times |location=New York |accessdate=2014-09-26 |url-status=live |archiveurl=https://web.archive.org/web/20140927022738/http://www.nytimes.com/2014/09/25/science/a-tiny-emissary-from-the-ancient-past.html |archivedate=27 September 2014}}</ref> It is widely accepted that current life on Earth descends from an RNA world,<ref name="RNA">*{{cite journal |last1=Copley |first1=Shelley D. |last2=Smith |first2=Eric |last3=Morowitz |first3=Harold J. |authorlink3=Harold J. Morowitz |date=December 2007 |title=The origin of the RNA world: Co-evolution of genes and metabolism |url=http://tuvalu.santafe.edu/~desmith/PDF_pubs/Copley_BOG.pdf |journal=Bioorganic Chemistry |volume=35 |issue=6 |pages=430–443 |doi=10.1016/j.bioorg.2007.08.001 |pmid=17897696 |accessdate=2015-06-08 |quote=The proposal that life on Earth arose from an RNA world is widely accepted. |url-status=live |archiveurl=https://web.archive.org/web/20130905070129/http://tuvalu.santafe.edu/~desmith/PDF_pubs/Copley_BOG.pdf |archivedate=5 September 2013}}<br />
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The RNA world hypothesis describes an early Earth with self-replicating and catalytic RNA but no DNA or proteins. It is widely accepted that current life on Earth descends from an RNA world, although RNA-based life may not have been the first life to exist. The structure of the ribosome has been called the "smoking gun," as it showed that the ribosome is a ribozyme, with a central core of RNA and no amino acid side chains within 18 angstroms of the active site where peptide bond formation is catalyzed.<br />
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RNA世界假说描述了一个具有自我复制和催化能力的RNA,但没有DNA或蛋白质的早期地球。<ref name="NYT-20140925-CZ">{{cite news |last=Zimmer |first=Carl |date=25 September 2014 |title=A Tiny Emissary From the Ancient Past |url=https://www.nytimes.com/2014/09/25/science/a-tiny-emissary-from-the-ancient-past.html |newspaper=The New York Times |location=New York |accessdate=2014-09-26 |url-status=live |archiveurl=https://web.archive.org/web/20140927022738/http://www.nytimes.com/2014/09/25/science/a-tiny-emissary-from-the-ancient-past.html |archivedate=27 September 2014}}</ref> 现在普遍认为现在地球上的生命起源于一个RNA世界,尽管基于RNA的生命可能并不是最早存在的生命。<ref name="RNA">*{{cite journal |last1=Copley |first1=Shelley D. |last2=Smith |first2=Eric |last3=Morowitz |first3=Harold J. |authorlink3=Harold J. Morowitz |date=December 2007 |title=The origin of the RNA world: Co-evolution of genes and metabolism |url=http://tuvalu.santafe.edu/~desmith/PDF_pubs/Copley_BOG.pdf |journal=Bioorganic Chemistry |volume=35 |issue=6 |pages=430–443 |doi=10.1016/j.bioorg.2007.08.001 |pmid=17897696 |accessdate=2015-06-08 |quote=The proposal that life on Earth arose from an RNA world is widely accepted. |url-status=live |archiveurl=https://web.archive.org/web/20130905070129/http://tuvalu.santafe.edu/~desmith/PDF_pubs/Copley_BOG.pdf |archivedate=5 September 2013}}***缺乏对应英文***这个结论是由许多独立的证据得出的,例如观察到RNA是翻译过程的核心,并且小RNA可以催化生命所需的所有化学基团和信息转移。***缺乏对应英文***核糖体的结构被称为 "确凿的证据",因为它表明核糖体是一个核酶,其核心是RNA,并且在催化肽键形成的活性位点18埃以内没有氨基酸侧链。<br />
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The concept of the RNA world was first proposed in 1962 by [[Alexander Rich]],<ref>{{cite journal |last1=Neveu |first1=Marc |last2=Kim |first2=Hyo-Joong |last3=Benner |first3=Steven A. |date=22 April 2013 |title=The 'Strong' RNA World Hypothesis: Fifty Years Old |journal=Astrobiology |volume=13 |issue=4 |pages=391–403 |bibcode=2013AsBio..13..391N |doi=10.1089/ast.2012.0868 |pmid=23551238 |ref=harv}}</ref> and the term was coined by [[Walter Gilbert]] in 1986.<ref name="Cech2012">{{cite journal |last=Cech |first=Thomas R. |authorlink=Thomas Cech |date=July 2012 |title=The RNA Worlds in Context |journal=Cold Spring Harbor Perspectives in Biology |volume=4 |issue=7 |page=a006742 |doi=10.1101/cshperspect.a006742 |pmc=3385955 |pmid=21441585}}</ref><ref>{{cite journal |last=Gilbert |first=Walter |authorlink=Walter Gilbert |date=20 February 1986 |title=Origin of life: The RNA world |journal=Nature |volume=319 |issue=6055 |page=618 |bibcode=1986Natur.319..618G |doi=10.1038/319618a0 |s2cid=8026658 }}</ref> <br />
<br />
The concept of the RNA world was first proposed in 1962 by Alexander Rich, and the term was coined by Walter Gilbert in 1986. <br />
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RNA世界的概念是由亚历山大·里奇Alexander Rich在1962年首次提出的<ref>{{cite journal |last1=Neveu |first1=Marc |last2=Kim |first2=Hyo-Joong |last3=Benner |first3=Steven A. |date=22 April 2013 |title=The 'Strong' RNA World Hypothesis: Fifty Years Old |journal=Astrobiology |volume=13 |issue=4 |pages=391–403 |bibcode=2013AsBio..13..391N |doi=10.1089/ast.2012.0868 |pmid=23551238 |ref=harv}}</ref> ,而这个术语则是由沃尔特·吉尔伯特Walter Gilbert在1986年创造的。<ref name="Cech2012">{{cite journal |last=Cech |first=Thomas R. |authorlink=Thomas Cech |date=July 2012 |title=The RNA Worlds in Context |journal=Cold Spring Harbor Perspectives in Biology |volume=4 |issue=7 |page=a006742 |doi=10.1101/cshperspect.a006742 |pmc=3385955 |pmid=21441585}}</ref><ref>{{cite journal |last=Gilbert |first=Walter |authorlink=Walter Gilbert |date=20 February 1986 |title=Origin of life: The RNA world |journal=Nature |volume=319 |issue=6055 |page=618 |bibcode=1986Natur.319..618G |doi=10.1038/319618a0 |s2cid=8026658 }}</ref> <br />
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In March 2020, astronomer Tomonori Totani presented a statistical approach for explaining how an initial active RNA molecule might have been produced randomly in the [[universe]] sometime since the [[Big Bang]].<ref name="UT-20200310">{{cite news |last=Gough |first=Evan |title=Life Could be Common Across the Universe, Just Not in Our Region |url=https://www.universetoday.com/145304/life-could-be-common-across-the-universe-just-not-in-our-region/ |date=10 March 2020 |work=[[Universe Today]] |accessdate=15 March 2020 }}</ref><ref name="SR-20200203">{{cite journal |last=Totani |first=Tomonori |title=Emergence of life in an inflationary universe |date=3 February 2020 |journal=[[Scientific Reports]] |volume=10 |number=1671 |pages=1671 |doi=10.1038/s41598-020-58060-0 |pmid=32015390 |pmc=6997386 |arxiv=1911.08092 |bibcode=2020NatSR..10.1671T |doi-access=free }}</ref><br />
<br />
In March 2020, astronomer Tomonori Totani presented a statistical approach for explaining how an initial active RNA molecule might have been produced randomly in the universe sometime since the Big Bang.<br />
<br />
在2020年3月,天文学家户谷友则 Tomonori Totani提出了一种统计方法,用于解释初始的活性RNA分子是如何在宇宙大爆炸后某个时间随机产生的。<ref name="UT-20200310">{{cite news |last=Gough |first=Evan |title=Life Could be Common Across the Universe, Just Not in Our Region |url=https://www.universetoday.com/145304/life-could-be-common-across-the-universe-just-not-in-our-region/ |date=10 March 2020 |work=[[Universe Today]] |accessdate=15 March 2020 }}</ref><ref name="SR-20200203">{{cite journal |last=Totani |first=Tomonori |title=Emergence of life in an inflationary universe |date=3 February 2020 |journal=[[Scientific Reports]] |volume=10 |number=1671 |pages=1671 |doi=10.1038/s41598-020-58060-0 |pmid=32015390 |pmc=6997386 |arxiv=1911.08092 |bibcode=2020NatSR..10.1671T |doi-access=free }}</ref><br />
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===系统发育和最后的普遍共同祖先 Phylogeny and LUCA===<br />
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[[File:Phylogenic Tree-en.svg|upright=1.65|thumb|A [[cladistics|cladogram]] demonstrating extreme [[hyperthermophile]]s as occur in volcanic hot springs at the base of the [[Phylogenetic tree|phylogenetic tree of life 一个描述出现在生命系统发育树基部的火山热泉中的极端超嗜热菌的进化分枝图。]]]]<br />
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<br />
<br />
The most commonly accepted location of the root of the tree of life is between a monophyletic domain [[Bacteria]] and a clade formed by [[Archaea]] and [[Eukaryota]] of what is referred to as the "traditional tree of life" based on several molecular studies starting with [[Carl Woese]].<ref>{{cite book |editor1-first=David R. |editor1-last=Boone |editor2-first=Richard W. |editor2-last=Castenholz |editor3-first=George M. |editor3-last=Garrity |title=The ''Archaea'' and the Deeply Branching and Phototrophic ''Bacteria'' |series=Bergey's Manual of Systematic Bacteriology |isbn=978-0-387-21609-6 |url=https://www.springer.com/life+sciences/microbiology/book/978-0-387-98771-2 |url-status=live |archiveurl=https://web.archive.org/web/20141225112809/http://www.springer.com/life+sciences/microbiology/book/978-0-387-98771-2 |archivedate=25 December 2014|publisher=Springer |year=2001 }}{{page needed|date=June 2014}}</ref><ref>{{cite journal |vauthors=Woese CR, Fox GE |title= Phylogenetic structure of the prokaryotic domain: the primary kingdoms. |journal= Proc Natl Acad Sci U S A |volume=74|pages= 5088–5090 |year=1977 |issue= 11 |pmid=270744 |pmc=432104|doi=10.1073/pnas.74.11.5088|bibcode= 1977PNAS...74.5088W }}</ref><br />
<br />
The most commonly accepted location of the root of the tree of life is between a monophyletic domain Bacteria and a clade formed by Archaea and Eukaryota of what is referred to as the "traditional tree of life" based on several molecular studies starting with Carl Woese.<br />
<br />
根据从卡尔·沃斯 Carl Woese 开始的一些分子研究,对于生命树的根部的位置,最普遍接受的观点是位于单系域细菌和一个由古细菌和真核生物组成的演化枝之间,这被称为“传统生命树”。<ref>{{cite book |editor1-first=David R. |editor1-last=Boone |editor2-first=Richard W. |editor2-last=Castenholz |editor3-first=George M. |editor3-last=Garrity |title=The ''Archaea'' and the Deeply Branching and Phototrophic ''Bacteria'' |series=Bergey's Manual of Systematic Bacteriology |isbn=978-0-387-21609-6 |url=https://www.springer.com/life+sciences/microbiology/book/978-0-387-98771-2 |url-status=live |archiveurl=https://web.archive.org/web/20141225112809/http://www.springer.com/life+sciences/microbiology/book/978-0-387-98771-2 |archivedate=25 December 2014|publisher=Springer |year=2001 }}{{page needed|date=June 2014}}</ref><ref>{{cite journal |vauthors=Woese CR, Fox GE |title= Phylogenetic structure of the prokaryotic domain: the primary kingdoms. |journal= Proc Natl Acad Sci U S A |volume=74|pages= 5088–5090 |year=1977 |issue= 11 |pmid=270744 |pmc=432104|doi=10.1073/pnas.74.11.5088|bibcode= 1977PNAS...74.5088W }}</ref><br />
<br />
<br />
A very small minority of studies have concluded differently, namely that the root is in the domain Bacteria, either in the phylum Firmicutes or’’’<font color=’’#32CD32’’> that the phylum Chloroflexi is basal to a clade with Archaea+Eukaryotes and the rest of Bacteria as proposed by Thomas Cavalier-Smith. </font>’’’More recently, Peter Ward has proposed an alternative view which is rooted in abiotic RNA synthesis which becomes enclosed within a capsule and then creates RNA ribozyme replicates. It is proposed that this then bifurcates between Dominion Ribosa (RNA life), and after the loss of ribozymes RNA viruses as Domain Viorea, and Dominion Terroa, which after creating a large cell within a lipid wall, creating DNA the 20 based amino acids and the triplet code, is established as the last universal common ancestor or LUCA, of earlier phylogenic trees.<br />
<br />
极少数的研究得出了不同的结论,即生命树的根部在细菌域中,要么在厚壁菌门中,要么是在绿弯菌门中,是古细菌+真核生物组成的一个演化枝和其余的细菌的基础,按照托马斯·卡弗利尔-史密斯Thomas Cavalier-Smith 所提出的那样。最近,彼得·沃德 Peter Ward 提出了另一种基于非生物的 RNA 合成的观点,该合成被包裹在一个胶囊中,然后产生RNA核酶复制品。有人提出,这然后在核糖核酸主导(RNA生命)之间分岔,在失去核酶RNA后病毒成为病毒主导,在脂质壁内形成一个大隔室,在20种氨基酸和三联子密码基础上形成DNA后成为细胞主导,它被确立为早期系统发育树的最后一个普遍共同祖先或LUCA。<br />
<br />
<br />
In 2016, a set of 355 genes likely present in the Last Universal Common Ancestor (LUCA) of all organisms living on Earth was identified. A total of 6.1 million prokaryotic protein coding genes from various phylogenic trees were sequenced, identifying 355 protein clusters from amongst 286,514 protein clusters that were probably common to LUCA. The results <br />
<br />
2016年,一组355个基因被识别为可能存在于生活在地球上的所有生物的最后一个普遍共同祖先(LUCA)中。对来自各种系统发育树的610万个原核生物蛋白编码基因进行了测序,从286,514个蛋白簇中识别了355个蛋白簇,它们很可能是LUCA共有的。结果<br />
<br />
| doi = 10.1016/0079-6107(95)00004-7<br />
<br />
< blockquote >. . . depict LUCA as anaerobic, CO<sub>2</sub>-fixing, H<sub>2</sub>-dependent with a Wood–Ljungdahl pathway, N<sub>2</sub>-fixing and thermophilic. LUCA's biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosylmethionine-dependent methylations." <br />
<br />
..说明LUCA是厌氧的、固定二氧化碳的、氢气依赖的且具有Wood-Ljungdahl通路的、固定氮气的和嗜热的。LUCA的生物化学中充斥着FeS簇和自由基反应机制。它的辅因子揭示了对过渡金属、黄素、S-腺苷甲硫氨酸、辅酶A、铁氧化还原蛋白、钼蝶呤、柯啉环和硒的依赖性。其遗传密码需要核苷修饰和S-腺苷甲硫氨酸依赖的甲基化"。<br />
| pmid = 7542789<br />
<br />
< /blockquote >The results depict methanogenic clostridia as a basal clade in the 355 phylogenies examined, and suggest that LUCA inhabited an anaerobic hydrothermal vent setting in a geochemically active environment rich in H<sub>2</sub>, CO<sub>2</sub> and iron.<br />
<br />
结果显示在所研究的355个系统发育中,产甲烷的梭菌是一个基础演化枝,并表明LUCA栖息在厌氧热液喷口处且地理化学活性环境中富含氢气,二氧化碳和铁。<br />
<br />
| issue = 2<br />
<br />
}}</ref><ref><br />
<br />
A study at the University of Düsseldorf created phylogenic trees based upon 6 million genes from bacteria and archaea, and identified 355 protein families that were probably present in the LUCA. They were based upon an anaerobic metabolism fixing carbon dioxide and nitrogen. It suggests that the LUCA evolved in an environment rich in hydrogen, carbon dioxide and iron.<br />
<br />
杜塞尔多夫大学的一项研究基于细菌和古细菌的600万个基因创建了系统发育树,并识别出了很可能存在于 LUCA 中的355个蛋白质家族。它们是基于一种固定二氧化碳和氮的厌氧代谢。这表明LUCA是在一个富含氢、二氧化碳和铁的环境中进化的。<br />
<br />
===Key issues in abiogenesis===<br />
生物发生中的关键问题<br />
<br />
====What came first: protein or nucleic acids?====<br />
<br />
孰先孰后:蛋白质还是核酸?<br />
<br />
Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the [[genetic code]] arose.<ref name="Noller2012">{{cite journal |last=Noller |first=Harry F. |authorlink=Harry F. Noller |date=April 2012 |title=Evolution of protein synthesis from an RNA world. |journal=Cold Spring Harbor Perspectives in Biology |volume=4 |issue=4 |page=a003681 |doi=10.1101/cshperspect.a003681 |pmc=3312679 |pmid=20610545}}</ref><br />
<br />
[[Eugene Koonin]] said, < blockquote >Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of [[eternal inflation]] could suggest a way out of this conundrum because, in an infinite [[multiverse]] with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.<ref name="pmc1892545">{{cite journal |last=Koonin |first=Eugene V. |date=31 May 2007 |title=The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life |journal=Biology Direct |volume=2 |page=15 |doi=10.1186/1745-6150-2-15 |pmc=1892545 |pmid=17540027}}</ref>< /blockquote ><br />
<br />
Possible precursors for the evolution of protein synthesis include a mechanism to synthesize short peptide cofactors or form a mechanism for the duplication of RNA. It is likely that the ancestral ribosome was composed entirely of RNA, although some roles have since been taken over by proteins. Major remaining questions on this topic include identifying the selective force for the evolution of the ribosome and determining how the genetic code arose.<br />
<br />
蛋白质合成的进化的可能前体包括合成短肽辅因子的机制或形成RNA复制的机制。祖先的核糖体很可能完全由RNA组成,尽管有些作用已经被蛋白质取代了。关于这个主题的主要剩余问题包括确定核糖体进化的选择性力量和确定遗传密码是如何产生的。<br />
<br />
| volume = 36<br />
<br />
| issue = 2<br />
<br />
Eugene Koonin said, < blockquote >Despite considerable experimental and theoretical effort, no compelling scenarios currently exist for the origin of replication and translation, the key processes that together comprise the core of biological systems and the apparent pre-requisite of biological evolution. The RNA World concept might offer the best chance for the resolution of this conundrum but so far cannot adequately account for the emergence of an efficient RNA replicase or the translation system. The MWO ["many worlds in one"] version of the cosmological model of eternal inflation could suggest a way out of this conundrum because, in an infinite multiverse with a finite number of distinct macroscopic histories (each repeated an infinite number of times), emergence of even highly complex systems by chance is not just possible but inevitable.< /blockquote ><br />
<br />
尤金·库宁Eugene Koonin 说,<br />
< blockquote ><br />
尽管在实验和理论上做了大量的努力,但对于复制和翻译的起源,目前还没有令人信服的设想,而复制和翻译是共同构成了生物系统核心的关键过程,也是生物进化的明显先决条件。RNA世界概念可能为这一难题的解决提供了最好的机会,但迄今为止还不能充分说明高效RNA复制酶或翻译系统的出现。MWO["多世界合一"]版本的永恒膨胀的宇宙模型可能提出了解决这一难题的方法,因为在一个无限的多元宇宙中,有有限数量的不同的宏观历史(每个历史重复无限次),即使是高度复杂的系统的偶然出现,不仅是可能的,而且是不可避免的。<br />
</blockquote ><br />
<br />
====Emergence of the genetic code====<br />
遗传密码的出现<br />
<br />
See: [[Genetic code#Origin|Genetic code]].<br />
<br />
See: Genetic code.<br />
<br />
请参阅:遗传密码。<br />
<br />
====Error in translation catastrophe====<br />
灾难性翻译错误<br />
<br />
Hoffmann has shown that an early error-prone translation machinery can be stable against an error catastrophe of the type that had been envisaged as problematical for the origin of life, and was known as "Orgel's paradox".<ref>{{cite journal |last=Hoffmann |first=Geoffrey W. |authorlink=Geoffrey W. Hoffmann |date=25 June 1974 |title=On the origin of the genetic code and the stability of the translation apparatus |journal=[[Journal of Molecular Biology]] |volume=86 |issue=2 |pages=349–362 |doi=10.1016/0022-2836(74)90024-2 |pmid=4414916}}</ref><ref>{{cite journal |last=Orgel |first=Leslie E. |date=April 1963 |title=The Maintenance of the Accuracy of Protein Synthesis and its Relevance to Ageing |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=49 |issue=4 |pages=517–521 |bibcode=1963PNAS...49..517O |doi=10.1073/pnas.49.4.517 |pmc=299893 |pmid=13940312}}</ref><ref>{{cite journal |last=Hoffmann |first=Geoffrey W. |title=The Stochastic Theory of the Origin of the Genetic Code |date=October 1975 |journal=[[Annual Review of Physical Chemistry]] |volume=26 |pages=123–144 |bibcode=1975ARPC...26..123H |doi=10.1146/annurev.pc.26.100175.001011 }}</ref><br />
<br />
Hoffmann has shown that an early error-prone translation machinery can be stable against an error catastrophe of the type that had been envisaged as problematical for the origin of life, and was known as "Orgel's paradox".<br />
<br />
霍夫曼Hoffmann已经证明,早期容易出错的翻译机制可以稳定地抵御曾被设想为对生命起源有问题的那种错误灾难,被称为 "奥格尔悖论"。<br />
<br />
====Homochirality====<br />
同手性<br />
<br />
{{Main|Homochirality}}<br />
<br />
Homochirality refers to a geometric uniformity of some materials composed of [[chirality|chiral]] units. Chiral refers to nonsuperimposable 3D forms that are mirror images of one another, as are left and right hands. Living organisms use molecules that have the same chirality ("handedness"): with almost no exceptions,<ref>{{harvnb|Chaichian|Rojas|Tureanu|2014|pp=353–364}}</ref> amino acids are left-handed while nucleotides and [[Carbohydrate|sugars]] are right-handed. Chiral molecules can be synthesized, but in the absence of a chiral source or a chiral [[Catalysis|catalyst]], they are formed in a 50/50 mixture of both [[enantiomer]]s (called a racemic mixture). Known mechanisms for the production of non-racemic mixtures from racemic starting materials include: asymmetric physical laws, such as the [[electroweak interaction]]; asymmetric environments, such as those caused by [[Circular polarization|circularly polarized]] light, [[Quartz|quartz crystals]], or the Earth's rotation, [[statistical fluctuations]] during racemic synthesis,<ref name="Plasson2007">{{cite journal |last1=Plasson |first1=Raphaël |last2=Kondepudi |first2=Dilip K. |last3=Bersini |first3=Hugues |last4=Commeyras |first4=Auguste |last5=Asakura |first5=Kouichi |display-authors=3 |date=August 2007 |title=Emergence of homochirality in far-from-equilibrium systems: Mechanisms and role in prebiotic chemistry |journal=[[Chirality (journal)|Chirality]] |volume=19 |issue=8 |pages=589–600 |doi=10.1002/chir.20440 |pmid=17559107}} "Special Issue: Proceedings from the Eighteenth International Symposium on Chirality (ISCD-18), Busan, Korea, 2006"</ref> and [[spontaneous symmetry breaking]].<ref name="jafarpour2017">{{cite journal |last1=Jafarpour |first1=Farshid |last2=Biancalani |first2=Tommaso |last3=Goldenfeld |first3=Nigel |year=2017 |title=Noise-induced symmetry breaking far from equilibrium and the emergence of biological homochirality |journal=Physical Review E |volume=95 |issue=3 |pages=032407 |doi=10.1103/PhysRevE.95.032407|pmid=28415353 |bibcode=2017PhRvE..95c2407J |url=http://dspace.mit.edu/bitstream/1721.1/109170/1/PhysRevE.95.032407.pdf }}</ref><ref name="jafarpour2015">{{cite journal |last1=Jafarpour |first1=Farshid |last2=Biancalani |first2=Tommaso |last3=Goldenfeld |first3=Nigel |year=2015 |title=Noise-induced mechanism for biological homochirality of early life self-replicators |journal=Physical Review Letters |volume=115 |issue=15 |pages=158101 |doi=10.1103/PhysRevLett.115.158101|pmid=26550754 |arxiv=1507.00044 |bibcode=2015PhRvL.115o8101J |s2cid=9775791 }}</ref><ref name="frank1953">{{cite journal |last1=Frank |first1=F.C. |year=1953 |title=On spontaneous asymmetric synthesis |journal=Biochimica et Biophysica Acta |volume=11 |issue=4 |pages=459–463 |doi=10.1016/0006-3002(53)90082-1|pmid=13105666 }}</ref><br />
<br />
Homochirality refers to a geometric uniformity of some materials composed of chiral units. Chiral refers to nonsuperimposable 3D forms that are mirror images of one another, as are left and right hands. Living organisms use molecules that have the same chirality ("handedness"): with almost no exceptions, amino acids are left-handed while nucleotides and sugars are right-handed. Chiral molecules can be synthesized, but in the absence of a chiral source or a chiral catalyst, they are formed in a 50/50 mixture of both enantiomers (called a racemic mixture). Known mechanisms for the production of non-racemic mixtures from racemic starting materials include: asymmetric physical laws, such as the electroweak interaction; asymmetric environments, such as those caused by circularly polarized light, quartz crystals, or the Earth's rotation, statistical fluctuations during racemic synthesis, and spontaneous symmetry breaking.<br />
<br />
同手性是指由手性单元组成的某些材料的几何均匀性。手性是指不可重叠的三维形态,它们是彼此的镜像,就像左手和右手一样。生物体使用的分子具有相同的手性("利手性"):几乎没有例外,氨基酸是左旋的,而核苷酸和糖类是右旋的。手性分子可以合成,但在没有手性源或手性催化剂的情况下,它们是以两种对映体以50/50的混合物(称为外消旋混合物)形成的。已知从外消旋起始原料产生非外消旋混合物的机制包括:非对称物理定律,如弱电相互作用;非对称环境,如圆偏振光、石英晶体或地球自转引起的环境,外消旋合成过程中的统计波动,以及自发的对称性破缺。<br />
<br />
Once established, chirality would be selected for.<ref>{{cite journal |last=Clark |first=Stuart |authorlink=Stuart Clark (author) |date=July–August 1999 |title=Polarized Starlight and the Handedness of Life |journal=[[American Scientist]] |volume=87 |issue=4 |page=336 |bibcode=1999AmSci..87..336C |doi=10.1511/1999.4.336}}</ref> A small bias ([[enantiomeric excess]]) in the population can be amplified into a large one by [[Autocatalysis#Asymmetric autocatalysis|asymmetric autocatalysis]], such as in the [[Soai reaction]].<ref>{{cite journal |last1=Shibata |first1=Takanori |last2=Morioka |first2=Hiroshi |last3=Hayase |first3=Tadakatsu |last4=Choji |first4=Kaori |last5=Soai |first5=Kenso |display-authors=3 |date=17 January 1996 |title=Highly Enantioselective Catalytic Asymmetric Automultiplication of Chiral Pyrimidyl Alcohol |journal=Journal of the American Chemical Society |volume=118 |issue=2 |pages=471–472 |doi=10.1021/ja953066g }}</ref> In asymmetric autocatalysis, the catalyst is a chiral molecule, which means that a chiral molecule is catalyzing its own production. An initial enantiomeric excess, such as can be produced by polarized light, then allows the more abundant enantiomer to outcompete the other.<ref name="Soai2001">{{cite journal |last1=Soai |first1=Kenso |last2=Sato |first2=Itaru |last3=Shibata |first3=Takanori |year=2001 |title=Asymmetric autocatalysis and the origin of chiral homogeneity in organic compounds |journal=The Chemical Record |volume=1 |issue=4 |pages=321–332 |doi=10.1002/tcr.1017 |pmid=11893072}}</ref><br />
<br />
Once established, chirality would be selected for. A small bias (enantiomeric excess) in the population can be amplified into a large one by asymmetric autocatalysis, such as in the Soai reaction. In asymmetric autocatalysis, the catalyst is a chiral molecule, which means that a chiral molecule is catalyzing its own production. An initial enantiomeric excess, such as can be produced by polarized light, then allows the more abundant enantiomer to outcompete the other.<br />
<br />
一旦建立,手性将被选择。群体中的一个小偏差(对映体过量)可以通过不对称自催化放大成一个大的偏差,如在Soai反应中。在不对称自催化中,催化剂是一个手性分子,这意味着手性分子正在催化自己的生产。最初的对映体过量,例如可以通过偏振光产生,然后允许更丰富的对映体超过其他对映体。<br />
<br />
Clark has suggested that homochirality may have started in outer space, as the studies of the amino acids on the [[Murchison meteorite]] showed that [[Alanine|L-alanine]] is more than twice as frequent as its D form, and [[Glutamic acid|L-glutamic acid]] was more than three times prevalent than its D counterpart. Various chiral crystal surfaces can also act as sites for possible concentration and assembly of chiral monomer units into macromolecules.<ref>{{harvnb|Hazen|2005|p=184}}</ref><ref name=Meierhenrich>{{cite book|last1=Meierhenrich|first1=Uwe|title=Amino acids and the asymmetry of life caught in the act of formation|date=2008|publisher=Springer|location=Berlin|isbn=978-3540768869|pages=76–79}}</ref> Compounds found on meteorites suggest that the chirality of life derives from abiogenic synthesis, since amino acids from meteorites show a left-handed bias, whereas sugars show a predominantly right-handed bias, the same as found in living organisms.<ref name=StarStuff>{{cite journal |last=Mullen |first=Leslie |date=5 September 2005 |title=Building Life from Star-Stuff |url=http://www.astrobio.net/news-exclusive/building-life-from-star-stuff/ |journal=[[Astrobiology Magazine]] |accessdate=2015-06-15 |url-status=live |archiveurl=https://web.archive.org/web/20150714084344/http://www.astrobio.net/news-exclusive/building-life-from-star-stuff/ |archivedate=14 July 2015}}</ref><br />
<br />
Clark has suggested that homochirality may have started in outer space, as the studies of the amino acids on the Murchison meteorite showed that L-alanine is more than twice as frequent as its D form, and L-glutamic acid was more than three times prevalent than its D counterpart. Various chiral crystal surfaces can also act as sites for possible concentration and assembly of chiral monomer units into macromolecules. Compounds found on meteorites suggest that the chirality of life derives from abiogenic synthesis, since amino acids from meteorites show a left-handed bias, whereas sugars show a predominantly right-handed bias, the same as found in living organisms.<br />
<br />
克拉克 Clark认为,同手性可能始于外太空,因为对默奇森 Murchison陨石上氨基酸的研究表明,L-丙氨酸的出现频率是其D形式的两倍多,L-谷氨酸是其D形式的三倍多。各种手性晶体表面也可以作为手性单体单元可能集中和组装成大分子的场所。在陨石上发现的化合物表明,生命的手性来源于非生物合成,因为陨石上的氨基酸表现出左手旋偏向,而糖类则主要表现出右手旋偏向,这与在生物体中发现的相同。<br />
<br />
===Early universe with first stars===<br />
<br />
有第一颗恒星的早期宇宙<br />
<br />
{{Nature timeline}} {{Life timeline}}<br />
<br />
Soon after the [[Big Bang]], which occurred roughly 14 Gya, the only chemical elements present in the universe were hydrogen, helium, and lithium, the three lightest atoms in the periodic table. These elements gradually came together to form stars. These early stars were massive and short-lived, producing heavier elements through [[stellar nucleosynthesis]]. [[Carbon]], currently the [[Abundance of the chemical elements|fourth most abundant chemical element]] in the universe (after [[hydrogen]], [[helium]] and [[oxygen]]), was formed mainly in [[white dwarf stars]], particularly those bigger than two solar masses.<ref name="INV-20200706">{{cite news|last=Rabie|first=Passant|date=6 July 2020|title=Astronomers Have Found The Source Of Life In The Universe|work=[[Inverse (website)|Inverse]]|url=https://www.inverse.com/science/carbon-from-white-dwarfs|accessdate=7 July 2020}}</ref><ref name="NA-20200706">{{cite journal|author=Marigo, Paola|display-authors=et al.|date=6 July 2020|title=Carbon star formation as seen through the non-monotonic initial–final mass relation|url=https://www.nature.com/articles/s41550-020-1132-1|journal=[[Nature Astronomy]]|volume=152|arxiv=2007.04163|doi=10.1038/s41550-020-1132-1|bibcode=2020NatAs.tmp..143M|accessdate=7 July 2020|s2cid=220403402}}</ref><br />
<br />
Soon after the Big Bang, which occurred roughly 14 Gya, the only chemical elements present in the universe were hydrogen, helium, and lithium, the three lightest atoms in the periodic table. These elements gradually came together to form stars. These early stars were massive and short-lived, producing heavier elements through stellar nucleosynthesis. Carbon, currently the fourth most abundant chemical element in the universe (after hydrogen, helium and oxygen), was formed mainly in white dwarf stars, particularly those bigger than two solar masses.<br />
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在宇宙大爆炸发生后不久,大约140亿年前,宇宙中存在的化学元素只有氢、氦和锂,这是周期表中最轻的三种元素。这些元素逐渐聚集在一起,形成了恒星。这些早期的恒星质量大、寿命短,通过恒星核合成产生更重的元素。碳是目前宇宙中含量第四丰富的化学元素(仅次于氢、氦、氧),主要形成于白矮星,尤其是那些大于两个太阳质量的白矮星。<br />
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As these stars reached the end of their [[Stellar life cycle|lifecycles]], they ejected these heavier elements, among them carbon and oxygen, throughout the universe. These heavier elements allowed for the formation of new objects, including rocky planets and other bodies.<ref>{{Cite web | url=https://wmap.gsfc.nasa.gov/universe/uni_life.html |title = WMAP- Life in the Universe}}</ref><br />
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As these stars reached the end of their lifecycles, they ejected these heavier elements, among them carbon and oxygen, throughout the universe. These heavier elements allowed for the formation of new objects, including rocky planets and other bodies.<br />
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当这些恒星达到其生命周期的终点时,它们在整个宇宙中喷射出这些较重的元素,其中包括碳和氧。这些较重的元素使得新的物体得以形成,包括岩质行星和其他天体。<br />
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===Emergence of the Solar System===<br />
太阳系的出现<br />
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According to the [[nebular hypothesis]], the formation and evolution of the [[Solar System]] began 4.6 Gya with the [[gravitational collapse]] of a small part of a giant [[molecular cloud]].<ref>[http://www.astro.umass.edu/~myun/teaching/a100_old/solarnebulartheory.htm Formation of Solar Systems: Solar Nebular Theory.] University of Massachusetts Amherst, Department of Astronomy. Accessed on 27 September 2019.</ref> Most of the collapsing mass collected in the center, forming the [[Sun]], while the rest flattened into a [[protoplanetary disk]] out of which the [[planet]]s, [[Natural satellite|moons]], [[asteroid]]s, and other [[Small Solar System body|small Solar System bodies]] formed.<br />
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According to the nebular hypothesis, the formation and evolution of the Solar System began 4.6 Gya with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed.<br />
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根据星云假说,太阳系的形成和演化始于46亿年前,因为一个巨大的分子云的一小部分的引力塌缩。大部分塌缩的质量聚集在中心,形成了太阳,而其余的则压平成一个原行星盘,行星、卫星、小行星和其他小太阳系天体就是从这个原行星盘中形成的。<br />
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===Emergence of Earth===<br />
地球的出现<br />
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The Earth, formed 4.5 Gya, was at first inhospitable to any living organisms. Based on numerous observations and studies of the [[geological time scale|geological time-scale]], the [[Hadean]] Earth is thought to have had a [[secondary atmosphere]], formed through [[Degasification|degassing]] of the rocks that accumulated from [[planetesimal]] [[impact event|impactors]]. At first, it was thought that the Earth's [[atmosphere]] consisted of hydrogen compounds—[[methane]], [[ammonia]] and [[Water vapor]]—and that life began under such [[redox|reducing]] conditions, which are conducive to the formation of organic molecules. According to later models, suggested by studying ancient minerals, the atmosphere in the late Hadean period consisted largely of water vapor, [[nitrogen]] and [[carbon dioxide]], with smaller amounts of [[carbon monoxide]], [[hydrogen]], and [[sulfur]] compounds.<ref>{{cite journal |last=Kasting |first=James F. |authorlink=James Kasting |date=12 February 1993 |title=Earth's Early Atmosphere |url=http://wwwdca.iag.usp.br/www/material/fornaro/ACA410/Kasting%201993_EarthEarlyAtmos.pdf |journal=Science |volume=259 |issue=5097 |pages=920–926 |doi=10.1126/science.11536547 |pmid=11536547 |bibcode=1993Sci...259..920K |s2cid=21134564 |accessdate=2015-07-28 |ref=harv |url-status=dead |archiveurl=https://web.archive.org/web/20151010074651/http://wwwdca.iag.usp.br/www/material/fornaro/ACA410/Kasting%201993_EarthEarlyAtmos.pdf |archivedate=10 October 2015}}</ref> During its formation, the Earth lost a significant part of its initial mass, with a nucleus of the heavier rocky elements of the protoplanetary disk remaining.<ref>{{harvnb|Fesenkov|1959|p=9}}</ref> As a consequence, Earth lacked the [[gravity]] to hold any molecular hydrogen in its atmosphere, and rapidly lost it during the Hadean period, along with the bulk of the original inert gases. The solution of carbon dioxide in water is thought to have made the seas slightly [[acid]]ic, giving them a [[pH]] of about 5.5.<ref>{{Cite journal|last=Morse|first=John|date=September 1998|title=Hadean Ocean Carbonate Geochemistry|journal=Aquatic Geochemistry|volume=4|issue=3/4|pages=301–319|doi=10.1023/A:1009632230875|bibcode=1998MinM...62.1027M|s2cid=129616933}}</ref> The atmosphere at the time has been characterized as a "gigantic, productive outdoor chemical laboratory."<ref name="Follmann2009" /> It may have been similar to the mixture of gases released today by volcanoes, which still support some abiotic chemistry.<ref name="Follmann2009" /><br />
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The Earth, formed 4.5 Gya, was at first inhospitable to any living organisms. Based on numerous observations and studies of the geological time-scale, the Hadean Earth is thought to have had a secondary atmosphere, formed through degassing of the rocks that accumulated from planetesimal impactors. At first, it was thought that the Earth's atmosphere consisted of hydrogen compounds—methane, ammonia and Water vapor—and that life began under such reducing conditions, which are conducive to the formation of organic molecules. According to later models, suggested by studying ancient minerals, the atmosphere in the late Hadean period consisted largely of water vapor, nitrogen and carbon dioxide, with smaller amounts of carbon monoxide, hydrogen, and sulfur compounds. During its formation, the Earth lost a significant part of its initial mass, with a nucleus of the heavier rocky elements of the protoplanetary disk remaining. As a consequence, Earth lacked the gravity to hold any molecular hydrogen in its atmosphere, and rapidly lost it during the Hadean period, along with the bulk of the original inert gases. The solution of carbon dioxide in water is thought to have made the seas slightly acidic, giving them a pH of about 5.5. The atmosphere at the time has been characterized as a "gigantic, productive outdoor chemical laboratory."<br />
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地球,形成于45亿年前,起初是不适合任何生物体生存的。根据对地质学时间尺度的大量观察和研究,人们认为冥古代地球曾有过一个次级大气层,是通过小行星撞击物所积累的岩石脱气而形成的。起初,人们认为地球的大气层由氢化合物——甲烷、氨和水蒸气组成,生命就是在这种有利于有机分子形成的还原性条件下开始的。根据后来的模型,通过对古代矿物的研究提出,冥古代晚期的大气层主要由水蒸气、氮气和二氧化碳组成,还有少量的一氧化碳、氢气和硫化合物。在地球形成过程中,地球失去了其初始质量的很大一部分,原行星盘中较重的岩石元素组成的核仍然存在。因此,地球缺乏在大气层中容纳任何氢分子的引力,并且在冥古代迅速失去了它,以及大部分的原始惰性气体.。二氧化碳在水中形成的溶液被认为使海洋呈微酸性,使海洋的pH值约为5.5。当时的大气层被描述为 "巨大的、高产的露天化学实验室。"***缺乏对应英文:它可能与今天火山释放的混合气体相似,它仍然支持一些非生物化学。***<br />
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===Emergence of the ocean===<br />
海洋的出现<br />
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Oceans may have appeared first in the Hadean Eon, as soon as 200 My after the Earth formed, in a hot, 100 C, reducing environment, and the pH of about 5.8 rose rapidly towards neutral.This scenario has found support from the dating of 4.404 Gyo zircon crystals from metamorphosed quartzite of Mount Narryer in the Western Australia Jack Hills of the Pilbara, which provide evidence that oceans and continental crust existed within 150 Ma of Earth's formation.Despite the likely increased volcanism and existence of many smaller tectonic "platelets," it has been suggested that between 4.4-4.3 Gyo, the Earth was a water world, with little if any continental crust, an extremely turbulent atmosphere and a hydrosphere subject to intense ultraviolet (UV) light, from a T Tauri stage Sun, cosmic radiation and continued bolide impacts.<br />
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海洋可能最早出现在冥古宙,即地球形成后的2亿年,在一个100 C的高温的还原性环境中,pH值约为5.8,迅速上升到中性。这一假设已经得到了来自澳大利亚西部纳里尔山变质石英岩的4.404 Gyo锆石晶体的年代测定的支持。这一设想已经得到了来自澳大利亚西部的皮尔巴拉的杰克高地的纳瑞耶山的变质石英岩的44.04亿年前的锆石晶体的年代测定的支持,它提供了地球形成后1.5亿年前内存在海洋和大陆地壳的证据。尽管可能增加了火山活动,并存在许多较小的构造 "板块",但有人认为,在44-43亿年之间,地球是一个水世界,几乎没有大陆地壳,大气层极度动荡,水圈受到来自T金牛座阶段的太阳的强烈的紫外线(UV)照射、宇宙辐射和持续的天体撞击。<br />
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===Late heavy bombardment===<br />
晚期重型轰炸<br />
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The Hadean environment would have been highly hazardous to modern life. Frequent collisions with large objects, up to 500&nbsp;km in diameter, would have been sufficient to sterilize the planet and vaporize the oceans within a few months of impact, with hot steam mixed with rock vapor becoming high altitude clouds that would completely cover the planet. After a few months, the height of these clouds would have begun to decrease but the cloud base would still have been elevated for about the next thousand years. After that, it would have begun to rain at low altitude. For another two thousand years, rains would slowly have drawn down the height of the clouds, returning the oceans to their original depth only 3,000&nbsp;y after the impact event.<ref>{{cite journal |last1=Sleep |first1=Norman H. |last2=Zahnle |first2=Kevin J. |authorlink2=Kevin J. Zahnle |last3=Kasting |first3=James F. |last4=Morowitz |first4=Harold J. |authorlink4=Harold J. Morowitz |display-authors=3 |date=9 November 1989 |title=Annihilation of ecosystems by large asteroid impacts on early Earth |journal=Nature |volume=342 |issue=6246|pages=139–142 |url=https://www.researchgate.net/publication/11809063|bibcode=1989Natur.342..139S |doi=10.1038/342139a0 |pmid=11536616|s2cid=1137852 }}</ref><br />
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冥古代的环境对现代生命将是非常危险的。与直径达500公里的大型物体频繁碰撞,足以在撞击后的几个月内使地球成为不毛之地,并使海洋汽化,热蒸汽与岩石蒸汽混合,成为足以完全覆盖地球的高空云层。几个月后,这些云层的高度会开始降低,但在接下来的大约一千年里,云层的底部仍会升高。在那之后,低海拔地区就会开始下雨。在接下来的两千年里,雨水会慢慢地拉低云层的高度,使海洋只有在撞击事件发生3000年后才恢复到原来的深度。<br />
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Traditionally it was thought that during the period between 4.28<ref name="NAT-20170301" /><ref name="NYT-20170301" /> and 3.8&nbsp;Gya, changes in the orbits of the [[giant planet]]s may have caused a [[Late Heavy Bombardment|heavy bombardment]] by asteroids and [[comet]]s<ref>{{cite journal |last1=Gomes |first1=Rodney |last2=Levison |first2=Hal F. |authorlink2=Harold F. Levison |last3=Tsiganis |first3=Kleomenis |last4=Morbidelli |first4=Alessandro |authorlink4=Alessandro Morbidelli (astronomer) |date=26 May 2005 |title=Origin of the cataclysmic Late Heavy Bombardment period of the terrestrial planets |journal=Nature |volume=435 |issue=7041 |pages=466–469 |bibcode=2005Natur.435..466G |doi=10.1038/nature03676 |pmid=15917802|doi-access=free }}</ref> that pockmarked the [[Moon]] and the other inner planets ([[Mercury (planet)|Mercury]], [[Mars]], and presumably Earth and [[Venus]]). This would likely have repeatedly sterilized the planet, had life appeared before that time.<ref name="Follmann2009" /> Geologically, the Hadean Earth would have been far more active than at any other time in its history. Studies of [[meteorite]]s suggests that [[Radionuclide|radioactive isotopes]] such as [[aluminium-26]] with a [[half-life]] of 7.17&nbsp;ky, and [[potassium-40]] with a half-life of 1.25&nbsp;Gy, isotopes mainly produced in [[supernova]]e, were much more common.<ref>{{harvnb|Davies|2007|pp=61–73}}</ref> Internal heating as a result of [[Convection#Gravitational or buoyant convection|gravitational sorting]] between the [[Earth core|core]] and the [[Mantle (geology)|mantle]] would have caused a great deal of [[mantle convection]], with the probable result of many more smaller and more active tectonic plates than now exist.<br />
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传统上认为,在42.8亿年前到38亿年前之间的时期,巨行星轨道的变化可能造成了小行星和彗星对月球和其他内行星(水星、火星,大概还有地球和金星)的猛烈轰击。如果生命在那之前出现的话,这很可能会使这个星球反复成为不毛之地。从地质学上来说,冥古代地球会比历史上任何其他时间都要活跃得多。对陨石的研究表明,放射性同位素,如半衰期为7.17 千年的铝-26和半衰期为12.5亿年的钾-40,这些主要产生于超新星的同位素更为常见。由于地核和地幔之间的重力分选而产生的内部加热会引起大量的地幔对流,其结果可能是产生了比现在更小、更活跃的构造板块。<br />
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The time periods between such devastating environmental events give time windows for the possible origin of life in the early environments. If the deep marine hydrothermal setting was the site for the origin of life, then abiogenesis could have happened as early as 4.0-4.2&nbsp;Gya. If the site was at the surface of the Earth, abiogenesis could only have occurred between 3.7-4.0 Gya.<ref>{{cite journal |last1=Maher |first1=Kevin A. |last2=Stevenson |first2=David J. |date=18 February 1988 |title=Impact frustration of the origin of life |journal=Nature |volume=331 |issue=6157 |pages=612–614 |bibcode=1988Natur.331..612M |doi=10.1038/331612a0 |pmid=11536595|s2cid=4284492 }}</ref><br />
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这种毁灭性的环境事件之间的时间段,为早期环境中可能的生命起源提供了时间窗口。如果深海热液环境是生命起源的场所,那么自然发生可能早在40-42亿年前就发生了。如果地点在地球表面,那么自然发生只能发生在37-40亿年前之间。<br />
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Estimates of the production of organics from these sources suggest that the [[Late Heavy Bombardment]] before 3.5&nbsp;Ga within the early atmosphere made available quantities of organics comparable to those produced by terrestrial sources.<ref>{{cite journal |last1=Chyba |first1=Christopher |authorlink=Christopher Chyba |last2=Sagan |first2=Carl |authorlink2=Carl Sagan |date=9 January 1992 |title=Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life |journal=Nature |volume=355 |issue=6356 |pages=125–132 |bibcode=1992Natur.355..125C |doi=10.1038/355125a0 |pmid=11538392|s2cid=4346044 }}</ref><ref>{{cite journal |last1=Furukawa |first1=Yoshihiro |last2=Sekine |first2=Toshimori |last3=Oba |first3=Masahiro |last4=Kakegawa |first4=Takeshi |last5=Nakazawa |first5=Hiromoto |display-authors=3 |date=January 2009 |title=Biomolecule formation by oceanic impacts on early Earth |journal=Nature Geoscience |volume=2 |issue=1 |pages=62–66 |bibcode=2009NatGe...2...62F |doi=10.1038/NGEO383}}</ref><br />
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对这些来源的有机物的产生的估计表明,在35亿年前之前,早期大气层内的晚期重型轰炸使可获得的有机物的数量与陆地来源产生的有机物数量相当。<br />
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It has been estimated that the Late Heavy Bombardment may also have effectively sterilized the Earth's surface to a depth of tens of meters. If life evolved deeper than this, it would have also been shielded from the early high levels of ultraviolet radiation from the T Tauri stage of the Sun's evolution. Simulations of geothermically heated oceanic crust yield far more organics than those found in the Miller–Urey experiments. In the deep [[hydrothermal vent]]s, Everett Shock has found "there is an enormous thermodynamic drive to form organic compounds, as [[seawater]] and hydrothermal fluids, which are far from equilibrium, mix and move towards a more stable state."<ref>{{harvnb|Davies|1999|p=155}}</ref> Shock has found that the available energy is maximized at around 100–150 C, precisely the temperatures at which the [[Hyperthermophile|hyperthermophilic]] bacteria and [[Thermoacidophile|thermoacidophilic]] [[archaea]] have been found, at the base of the [[Phylogenetic tree|phylogenetic tree of life]] closest to the [[Last universal ancestor|Last Universal Common Ancestor]] (LUCA).<ref>{{harvnb|Bock|Goode|1996}}</ref><br />
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据估计,晚期重型轰炸还可能对数十米深的地球表面进行了有效的灭菌。如果生命进化到比这更深的地方,它也会被屏蔽在太阳进化的T金牛座阶段的早期高水平紫外线辐射之外。对地热加热的海洋地壳进行模拟,得到的有机物远比Miller–Urey实验中发现的多。在深层热液喷口中,埃弗雷特·休克 Everett Shock发现 "存在着形成有机化合物的巨大热力学驱动力,因为海水和热液远未达到平衡,混合并向更稳定的状态发展。"Shock发现,可用的能量在100-150 C左右达到最大,而这正是发现嗜热细菌和嗜热古细菌的温度,处于最接近最后普遍共同祖先(LUCA)的生命系统发育树的底部。<br />
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== 生命的最早证据:古生物学==<br />
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{{Main|Earliest known life forms}}<br />
[[File:Stromatolites.jpg|left|thumb|[[Precambrian]] [[stromatolite]]s in the Siyeh Formation, [[Glacier National Park (U.S.)|Glacier National Park]]. <br />
A 2002 study suggested that these 3.5 Gyo (billion year old) [[Geologic formation|formations]] contain fossilized [[cyanobacteria]] [[microorganism|microbes]]. This suggests they are evidence of one of the [[Earliest known life forms|earliest life forms]] on [[Earth]]. 冰川国家公园锡耶组 Siyeh Formation的前寒武纪叠层石。2002年的一项研究表明,这些35亿岁的岩层中含有蓝藻微生物化石。这表明它们是地球上最早的生命形式之一的证据。]] <br />
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[[File:Stromatolites in Sharkbay.jpg|thumb|Stromatolites in [[Shark Bay]] 鲨鱼湾中的石笋]]<br />
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The earliest life on Earth existed more than 3.5 Gya (billion years ago),<ref name="Origin1" /><ref name="Origin2" /><ref name="RavenJohnson2002" /> during the [[Eoarchean]] Era when sufficient crust had solidified following the molten Hadean Eon. The earliest physical evidence so far found consists of [[Micropaleontology#Microfossils|microfossils]] in the [[Nuvvuagittuq Greenstone Belt]] of Northern Quebec, in [[banded iron formation]] rocks at least 3.77 and possibly 4.28&nbsp;Gyo.<ref name="NAT-20170301" /><ref>{{cite web |url=http://www.cbc.ca/news/technology/oldest-record-life-earth-found-quebec-1.4004545 |title=Oldest traces of life on Earth found in Quebec, dating back roughly 3.8&nbsp;Gya |author=Mortillaro, Nicole |publisher=CBC News |date=1 March 2017 |accessdate=2 March 2017 |url-status=live |archiveurl=https://web.archive.org/web/20170301221842/http://www.cbc.ca/news/technology/oldest-record-life-earth-found-quebec-1.4004545 |archivedate=1 March 2017}}</ref> This finding suggested life developed very soon after oceans formed. The structure of the microbes was noted to be similar to bacteria found near [[hydrothermal vents]] in the modern era, and provided support for the hypothesis that abiogenesis began near hydrothermal vents.<ref name="4.3b oldest" /><ref name="NAT-20170301" /><br />
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地球上最早的生命存在于35亿年前,<ref name="Origin1" /><ref name="Origin2" /><ref name="RavenJohnson2002" />在始太古代时期,在熔化的冥古宙之后,充足的地壳已经凝固。迄今为止发现的最早的物理证据包括魁北克北部努夫雅集图克绿岩带中的微生物化石,位于至少37.7亿岁,也可能42.8亿岁的带状铁层岩石中。<ref name="NAT-20170301" /><ref>{{cite web |url=http://www.cbc.ca/news/technology/oldest-record-life-earth-found-quebec-1.4004545 |title=Oldest traces of life on Earth found in Quebec, dating back roughly 3.8&nbsp;Gya |author=Mortillaro, Nicole |publisher=CBC News |date=1 March 2017 |accessdate=2 March 2017 |url-status=live |archiveurl=https://web.archive.org/web/20170301221842/http://www.cbc.ca/news/technology/oldest-record-life-earth-found-quebec-1.4004545 |archivedate=1 March 2017}}</ref>这个发现表明生命在海洋形成后不久便出现了。据悉,这种微生物的结构与现代热液喷口附近发现的细菌相似,为无生源论始于热液喷口附近的假说提供了支持。<br />
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Biogenic [[graphite]] has been found in 3.7&nbsp;Gyo metasedimentary rocks from southwestern [[Greenland]]<ref name="NG-20131208">{{cite journal |last1=Ohtomo |first1=Yoko |last2=Kakegawa |first2=Takeshi |last3=Ishida |first3=Akizumi |last4=Nagase |first4=Toshiro |last5=Rosing |first5=Minik T. |display-authors=3 |date=January 2014 |title=Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks |journal=[[Nature Geoscience]] |volume=7 |issue=1 |pages=25–28 |bibcode=2014NatGe...7...25O |doi=10.1038/ngeo2025 }}</ref> and [[microbial mat]] fossils found in 3.48&nbsp;Gyo sandstone from [[Western Australia]].<ref name="AP-20131113">{{cite news |last=Borenstein |first=Seth |date=13 November 2013 |title=Oldest fossil found: Meet your microbial mom |url=http://apnews.excite.com/article/20131113/DAA1VSC01.html |work=[[Excite]] |location=Yonkers, NY |publisher=[[Mindspark Interactive Network]] |agency=[[Associated Press]] |accessdate=2015-06-02 |url-status=live |archiveurl=https://web.archive.org/web/20150629230719/http://apnews.excite.com/article/20131113/DAA1VSC01.html |archivedate=29 June 2015}}</ref><ref name="AST-20131108">{{cite journal |last1=Noffke |first1=Nora |last2=Christian |first2=Daniel |last3=Wacey |first3=David |last4=Hazen |first4=Robert M. |authorlink4=Robert Hazen |date=16 November 2013 |title=Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ''ca.'' 3.48 Gyo Dresser Formation, Pilbara, Western Australia |journal=[[Astrobiology (journal)|Astrobiology]] |volume=13 |issue=12 |pages=1103–1124 |bibcode=2013AsBio..13.1103N |doi=10.1089/ast.2013.1030 |pmc=3870916 |pmid=24205812}}</ref> Evidence of early life in rocks from [[Akilia]] Island, near the [[Isua Greenstone Belt|Isua supracrustal belt]] in southwestern Greenland, dating to 3.7&nbsp;Gya have shown biogenic [[carbon isotope]]s.<ref name="NYT-20160831">{{cite news |last=Wade |first=Nicholas |title=World's Oldest Fossils Found in Greenland |url=https://www.nytimes.com/2016/09/01/science/oldest-fossils-on-earth.html |date=31 August 2016 |work=[[The New York Times]] |accessdate=31 August 2016 |url-status=live |archiveurl=https://web.archive.org/web/20160831185959/http://www.nytimes.com/2016/09/01/science/oldest-fossils-on-earth.html |archivedate=31 August 2016}}</ref><ref>{{harvnb|Davies|1999}}</ref> In other parts of the Isua supracrustal belt, graphite inclusions trapped within [[garnet]] crystals are connected to the other elements of life: oxygen, nitrogen, and possibly phosphorus in the form of [[phosphate]], providing further evidence for life 3.7&nbsp;Gya.<ref>{{Cite journal |last1=Hassenkam|first1=T. |last2=Andersson |first2=M.P. |last3=Dalby|first3=K.N. |last4=Mackenzie |first4=D.M.A.|last5=Rosing |first5=M.T. |title=Elements of Eoarchean life trapped in mineral inclusions |journal=Nature |doi=10.1038/nature23261 |pmid=28738409 |volume=548|issue=7665|pages=78–81 |year=2017 |bibcode=2017Natur.548...78H|s2cid=205257931 }}</ref> At Strelley Pool, in the [[Pilbara]] region of Western Australia, compelling evidence of early life was found in [[pyrite]]-bearing sandstone in a fossilized beach, that showed rounded tubular cells that [[Redox|oxidized]] sulfur by [[photosynthesis]] in the absence of oxygen.<ref name="TG-20131113-JP">{{cite news |last=Pearlman |first=Jonathan |date=13 November 2013 |title=Oldest signs of life on Earth found |url=https://www.telegraph.co.uk/news/science/science-news/10445788/Oldest-signs-of-life-on-Earth-found.html |newspaper=[[The Daily Telegraph]] |location=London |accessdate=2014-12-15 |url-status=live |archiveurl=https://web.archive.org/web/20141216062531/http://www.telegraph.co.uk/news/science/science-news/10445788/Oldest-signs-of-life-on-Earth-found.html |archivedate=16 December 2014}}</ref><ref>{{cite journal |last=O'Donoghue |first=James |date=21 August 2011 |url=https://www.newscientist.com/article/dn20813-oldest-reliable-fossils-show-early-life-was-a-beach.html |title=Oldest reliable fossils show early life was a beach |journal=[[New Scientist]] |url-status=live |archiveurl=https://web.archive.org/web/20150630201918/http://www.newscientist.com/article/dn20813-oldest-reliable-fossils-show-early-life-was-a-beach.html |archivedate=30 June 2015|doi=10.1016/S0262-4079(11)62064-2 |volume=211 |page=13 }}</ref><ref>{{cite journal |last1=Wacey |first1=David |last2=Kilburn |first2=Matt R. |last3=Saunders |first3=Martin |last4=Cliff |first4=John |last5=Brasier |first5=Martin D. |authorlink5=Martin Brasier |display-authors=3 |date=October 2011 |title=Microfossils of sulphur-metabolizing cells in 3.4-billion-year-old rocks of Western Australia |journal=Nature Geoscience |volume=4 |issue=10 |pages=698–702 |bibcode=2011NatGe...4..698W |doi=10.1038/ngeo1238}}</ref> Further research on [[zircon]]s from Western Australia in 2015 suggested that life likely existed on Earth at least 4.1 Gya.<ref name="AP-20151019">{{cite news |last=Borenstein |first=Seth |title=Hints of life on what was thought to be desolate early Earth |url=https://apnews.com/e6be2537b4cd46ffb9c0585bae2b2e51 |date=19 October 2015 |work=AP News |publisher=[[Associated Press]] |accessdate=9 October 2018}}</ref><ref name="PNAS-20151014-pdf">{{cite journal |last1=Bell |first1=Elizabeth A. |last2=Boehnike |first2=Patrick |last3=Harrison |first3=T. Mark |last4=Mao |first4=Wendy L. |display-authors=3 |date=19 October 2015 |title=Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon|journal=Proc. Natl. Acad. Sci. U.S.A. |doi=10.1073/pnas.1517557112|pages=14518–14521 |pmid=26483481 |pmc=4664351 |volume=112 |issue=47 |bibcode=2015PNAS..11214518B}} Early edition, published online before print.</ref><ref name="UCLA-20151019">{{cite web |last1=Wolpert |first1=Stuart |title=Life on Earth likely started at least 4.1 billion years ago – much earlier than scientists had thought |url=http://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-years-ago-much-earlier-than-scientists-had-thought |date=19 October 2015 |publisher=[[ULCA]] |accessdate=20 October 2015 |url-status=live |archiveurl=https://web.archive.org/web/20151020164038/http://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-years-ago-much-earlier-than-scientists-had-thought |archivedate=20 October 2015}}</ref><br />
<br />
人们在格陵兰岛西南部37亿岁的变质沉积岩中发现了生物来源的石墨<ref name="NG-20131208">{{cite journal |last1=Ohtomo |first1=Yoko |last2=Kakegawa |first2=Takeshi |last3=Ishida |first3=Akizumi |last4=Nagase |first4=Toshiro |last5=Rosing |first5=Minik T. |display-authors=3 |date=January 2014 |title=Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks |journal=[[Nature Geoscience]] |volume=7 |issue=1 |pages=25–28 |bibcode=2014NatGe...7...25O |doi=10.1038/ngeo2025 }}</ref> ,在西澳大利亚距今34.8亿年前的砂岩中发现了微生物垫层化石<ref name="AP-20131113">{{cite news |last=Borenstein |first=Seth |date=13 November 2013 |title=Oldest fossil found: Meet your microbial mom |url=http://apnews.excite.com/article/20131113/DAA1VSC01.html |work=[[Excite]] |location=Yonkers, NY |publisher=[[Mindspark Interactive Network]] |agency=[[Associated Press]] |accessdate=2015-06-02 |url-status=live |archiveurl=https://web.archive.org/web/20150629230719/http://apnews.excite.com/article/20131113/DAA1VSC01.html |archivedate=29 June 2015}}</ref><ref name="AST-20131108">{{cite journal |last1=Noffke |first1=Nora |last2=Christian |first2=Daniel |last3=Wacey |first3=David |last4=Hazen |first4=Robert M. |authorlink4=Robert Hazen |date=16 November 2013 |title=Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ''ca.'' 3.48 Gyo Dresser Formation, Pilbara, Western Australia |journal=[[Astrobiology (journal)|Astrobiology]] |volume=13 |issue=12 |pages=1103–1124 |bibcode=2013AsBio..13.1103N |doi=10.1089/ast.2013.1030 |pmc=3870916 |pmid=24205812}}</ref>。在格陵兰岛西南部伊苏亚上地壳带附近的阿基利亚岛的岩石中发现了早期生命的证据,这些可追溯到37亿年前的证据中发现了生源碳同位素<ref name="NYT-20160831">{{cite news |last=Wade |first=Nicholas |title=World's Oldest Fossils Found in Greenland |url=https://www.nytimes.com/2016/09/01/science/oldest-fossils-on-earth.html |date=31 August 2016 |work=[[The New York Times]] |accessdate=31 August 2016 |url-status=live |archiveurl=https://web.archive.org/web/20160831185959/http://www.nytimes.com/2016/09/01/science/oldest-fossils-on-earth.html |archivedate=31 August 2016}}</ref><ref>{{harvnb|Davies|1999}}</ref> 。在伊苏亚上地壳带的其他地方,被困在石榴石晶体内的石墨包裹体与生命的其他元素相连:氧、氮和可能以磷酸盐形式存在的磷,为37亿年前的生命提供了进一步的证据<ref>{{Cite journal |last1=Hassenkam|first1=T. |last2=Andersson |first2=M.P. |last3=Dalby|first3=K.N. |last4=Mackenzie |first4=D.M.A.|last5=Rosing |first5=M.T. |title=Elements of Eoarchean life trapped in mineral inclusions |journal=Nature |doi=10.1038/nature23261 |pmid=28738409 |volume=548|issue=7665|pages=78–81 |year=2017 |bibcode=2017Natur.548...78H|s2cid=205257931 }}</ref> 。在西澳大利亚皮尔巴拉地区的斯特雷利池,在一个化石滩的含黄铁矿砂岩中发现了早期生命的令人信服的证据,它显示了圆形的管状细胞,在没有氧气的情况下通过光合作用氧化硫。2015年对西澳大利亚的锆石的进一步研究表明,生命很可能在至少41亿年前就存在于地球上。<ref name="AP-20151019">{{cite news |last=Borenstein |first=Seth |title=Hints of life on what was thought to be desolate early Earth |url=https://apnews.com/e6be2537b4cd46ffb9c0585bae2b2e51 |date=19 October 2015 |work=AP News |publisher=[[Associated Press]] |accessdate=9 October 2018}}</ref><ref name="PNAS-20151014-pdf">{{cite journal |last1=Bell |first1=Elizabeth A. |last2=Boehnike |first2=Patrick |last3=Harrison |first3=T. Mark |last4=Mao |first4=Wendy L. |display-authors=3 |date=19 October 2015 |title=Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon|journal=Proc. Natl. Acad. Sci. U.S.A. |doi=10.1073/pnas.1517557112|pages=14518–14521 |pmid=26483481 |pmc=4664351 |volume=112 |issue=47 |bibcode=2015PNAS..11214518B}} Early edition, published online before print.</ref><ref name="UCLA-20151019">{{cite web |last1=Wolpert |first1=Stuart |title=Life on Earth likely started at least 4.1 billion years ago – much earlier than scientists had thought |url=http://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-years-ago-much-earlier-than-scientists-had-thought |date=19 October 2015 |publisher=[[ULCA]] |accessdate=20 October 2015 |url-status=live |archiveurl=https://web.archive.org/web/20151020164038/http://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-years-ago-much-earlier-than-scientists-had-thought |archivedate=20 October 2015}}</ref><br />
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<br />
== 20世纪60年代以前的概念演变史:生物学 Conceptual history until the 1960s: biology ==<br />
<br />
=== 泛种论 Panspermia ===<br />
泛种论<br />
{{Main|Panspermia}}<br />
<br />
Panspermia is the [[hypothesis]] that [[life]] exists throughout the [[universe]], distributed by [[meteoroids]], [[asteroids]], [[comets]]<ref name="cometary panspermia"><br />
<br />
泛种论是一种假说,即生命存在于整个宇宙,由流星体、小行星、彗星分布。<ref name="cometary panspermia"><br />
<br />
The panspermia hypothesis does not attempt to explain how life first originated but merely shifts the origin to another planet or a comet. The advantage of an extraterrestrial origin of primitive life is that life is not required to have formed on each planet it occurs on, but rather in a single location, and then spread about the [[galaxy]] to other star systems via cometary and/or meteorite impact.<ref name="NYT-20160912">{{cite news |last=Chang |first=Kenneth |title=Visions of Life on Mars in Earth's Depths |url=https://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |date=12 September 2016 |work=[[The New York Times]] |accessdate=12 September 2016 |url-status=live |archiveurl=https://web.archive.org/web/20160912225220/http://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |archivedate=12 September 2016}}</ref> <br />
<br />
Evidence for the panspermia hypothesis is scant, but it finds some support in studies of [[Martian meteorite]]s found in [[Antarctica]] and in studies of [[extremophile]] microbes' survival in outer space tests.<ref>{{cite journal |last=Clark |first=Stuart |date=25 September 2002 |title=Tough Earth bug may be from Mars |url=https://www.newscientist.com/article/dn2844 |journal=New Scientist |accessdate=2015-06-21 |url-status=live |archiveurl=https://web.archive.org/web/20141202003401/http://www.newscientist.com/article/dn2844 |archivedate=2 December 2014}}</ref><ref name="Gerda Horneck">{{cite journal |last1=Horneck |first1=Gerda |last2=Klaus |first2=David M. |last3=Mancinelli |first3=Rocco L. |date=March 2010 |title=Space Microbiology |journal=[[Microbiology and Molecular Biology Reviews]] |volume=74 |issue=1 |pages=121–156 |doi=10.1128/MMBR.00016-09 |pmc=2832349 |pmid=20197502|bibcode=2010MMBR...74..121H }}</ref><ref name="Rabbow">{{cite journal |last1=Rabbow |first1=Elke |last2=Horneck |first2=Gerda |last3=Rettberg |first3=Petra |last4=Schott |first4=Jobst-Ulrich |last5=Panitz |first5=Corinna |last6=L'Afflitto |first6=Andrea |last7=von Heise-Rotenburg |first7=Ralf |last8=Willnecker |first8=Reiner |last9=Baglioni |first9=Pietro |last10=Hatton |first10=Jason |last11=Dettmann |first11=Jan |last12=Demets |first12=René |last13=Reitz |first13=Günther |display-authors=3 |date=December 2009 |title=EXPOSE, an Astrobiological Exposure Facility on the International Space Station – from Proposal to Flight |journal=Origins of Life and Evolution of Biospheres |volume=39 |issue=6 |pages=581–598 |bibcode=2009OLEB...39..581R |doi=10.1007/s11084-009-9173-6|pmid=19629743|s2cid=19749414 }}</ref><ref>{{cite journal |last1=Onofri |first1=Silvano |last2=de la Torre |first2=Rosa |last3=de Vera |first3=Jean-Pierre |last4=Ott |first4=Sieglinde |last5=Zucconi |first5=Laura |last6=Selbmann |first6=Laura |last7=Scalzi |first7=Giuliano |last8=Venkateswaran |first8=Kasthuri J. |last9=Rabbow |first9=Elke |last10=Sánchez Iñigo |first10=Francisco J. |last11=Horneck |first11=Gerda |display-authors=3 |date=May 2012 |title=Survival of Rock-Colonizing Organisms After 1.5 Years in Outer Space |journal=Astrobiology |volume=12 |issue=5 |pages=508–516 |bibcode=2012AsBio..12..508O |doi=10.1089/ast.2011.0736 |pmid=22680696}}</ref><br />
<br />
泛种论假说并不试图解释生命最初是如何起源的,而只是将起源转移到另一颗行星或彗星上。原始生命的地外起源的优点是,生命不需要在它出现的每个星球上形成,而是在一个单一的位置,然后通过彗星和/或陨石撞击在银河系周围传播到其他恒星系统。泛种论假说的证据很少,但它在对南极洲发现的火星陨石的研究和对极端微生物在外太空测试中生存的研究中找到了一些支持。<br />
<br />
In August 2020, scientists reported that [[bacteria]] from Earth, particularly ''[[Deinococcus radiodurans]]'', which is highly resistant to [[environmental hazard]]s, were found to survive for three years in [[outer space]], based on studies conducted on the [[International Space Station]].<ref name="CNN-20200826">{{cite news |last=Strickland |first=Ashley |title=Bacteria from Earth can survive in space and could endure the trip to Mars, according to new study |url=https://www.cnn.com/2020/08/26/world/earth-mars-bacteria-space-scn/index.html |date=26 August 2020 |work=[[CNN News]] |accessdate=26 August 2020 }}</ref><ref name="FM-20200826">{{cite journal |author=Kawaguchi, Yuko |display-authors=et al. |title=DNA Damage and Survival Time Course of Deinococcal Cell Pellets During 3 Years of Exposure to Outer Space |date=26 August 2020 |journal=[[Frontiers in Microbiology]] |volume=11 |page=2050 |doi=10.3389/fmicb.2020.02050 |pmid=32983036 |pmc=7479814 |s2cid=221300151 |doi-access=free }}</ref><br />
<br />
2020年8月,科学家报告称,根据在国际空间站上进行的研究,发现来自地球的细菌,特别是对环境危害有很强抵抗力的耐辐射球菌,可以在外太空存活3年。<br />
<br />
====Origin of life posited directly after the Big Bang and have spread over the entire Universe====<br />
<br />
生命起源于宇宙大爆炸之后,并已遍布整个宇宙<br />
<br />
An extreme speculation is that the [[biochemistry]] of life could have begun as early as 17 My (million years) after the [[Big Bang]], during a [[Chronology of the universe#Speculative "habitable epoch"|habitable epoch]], and that life may exist throughout the [[universe]].<ref name="IJA-2014October_ARXIV-20131202">{{cite journal|last=Loeb|first=Abraham|authorlink=Abraham (Avi) Loeb|date=2014|title=The habitable epoch of the early universe|journal=[[International Journal of Astrobiology]]|volume=13|issue=4|pages=337–339|arxiv=1312.0613|bibcode=2014IJAsB..13..337L|citeseerx=10.1.1.748.4820|doi=10.1017/S1473550414000196|s2cid=2777386}}</ref><ref name="NYT-20141202">{{cite news|url=https://www.nytimes.com/2014/12/02/science/avi-loeb-ponders-the-early-universe-nature-and-life.html|title=Much-Discussed Views That Go Way Back|last=Dreifus|first=Claudia|date=2 December 2014|newspaper=[[The New York Times]]|accessdate=2014-12-03|archiveurl=https://web.archive.org/web/20141203010758/http://www.nytimes.com/2014/12/02/science/avi-loeb-ponders-the-early-universe-nature-and-life.html|archivedate=3 December 2014|url-status=live|location=New York|page=D2|authorlink=Claudia Dreifus}}</ref><br />
<br />
一种极端的推测是生命的生物化学可能早在大爆炸后1700万年就开始了,在一个适宜居住的时期,生命可能存在于整个宇宙中。<br />
<br />
====Panspermia by life brought from Mars to Earth====<br />
<br />
生命从火星带入地球的泛种论<br />
<br />
Carl Zimmer has speculated that the chemical conditions, including the presence of [[boron]], [[molybdenum]] and oxygen needed for the initial production of RNA, may have been better on early Mars than on early Earth.<ref name="NYT-20130912">{{cite news |last=Zimmer |first=Carl |date=12 September 2013 |title=A Far-Flung Possibility for the Origin of Life |url=https://www.nytimes.com/2013/09/12/science/space/a-far-flung-possibility-for-the-origin-of-life.html |newspaper=The New York Times |location=New York |accessdate=2015-06-15 |url-status=live |archiveurl=https://web.archive.org/web/20150708122622/http://www.nytimes.com/2013/09/12/science/space/a-far-flung-possibility-for-the-origin-of-life.html |archivedate=8 July 2015}}</ref><ref name="NS-20130829">{{cite journal |last=Webb |first=Richard |date=29 August 2013 |title=Primordial broth of life was a dry Martian cup-a-soup |url=https://www.newscientist.com/article/dn24120-primordial-broth-of-life-was-a-dry-martian-cupasoup.html |journal=New Scientist |accessdate=2015-06-16 |url-status=live |archiveurl=https://web.archive.org/web/20150424181341/http://www.newscientist.com/article/dn24120-primordial-broth-of-life-was-a-dry-martian-cupasoup.html |archivedate=24 April 2015}}</ref><ref>{{cite journal |author1=Wentao Ma |author2=Chunwu Yu |author3=Wentao Zhang |author4=Jiming Hu |display-authors=3 |date=November 2007 |title=Nucleotide synthetase ribozymes may have emerged first in the RNA world |journal=[[RNA (journal)|RNA]] |volume=13 |issue=11 |pages=2012–2019 |doi=10.1261/rna.658507 |pmc=2040096 |pmid=17878321}}</ref> If so, life-suitable molecules originating on Mars may have later migrated to Earth via [[Impact event|meteor ejections]].<br />
<br />
卡尔·齐默Carl Zimmer推测,火星早期的化学条件,包括最初生成RNA所需的硼,钼和氧的存在,可能比地球早期更好。如果是这样,起源于火星的适合生命的分子可能后来会通过流星喷射迁移到地球。<br />
<br />
=== Spontaneous generation ===<br />
自然发生<br />
====General acceptance of spontaneous generation until the 19th century====<br />
<br />
19世纪之前,人们普遍接受自然发生论。<br />
<br />
{{Main|Spontaneous generation}}<br />
<br />
Traditional religion attributed the origin of life to supernatural deities who created the natural world. ''Spontaneous generation,'' the first naturalistic theory of life arising from non-life, goes back to [[Aristotle]] and [[ancient Greek philosophy]], and continued to have support in Western scholarship until the 19th century.<ref>{{harvnb|Sheldon|2005}}</ref> Classical notions of spontaneous generation held that certain "lower" or "vermin" animals are generated by decaying organic substances. According to Aristotle, it was readily observable that [[aphid]]s arise from dew on plants, [[fly|flies]] from putrid matter, mice from dirty hay, crocodiles from rotting sunken logs, and so on.<ref>{{harvnb|Lennox|2001|pp=229–258}}</ref> A related theory was ''heterogenesis'': that some forms of life could arise from different forms (e.g. bees from flowers).<ref>{{harvnb|Vartanian|1973|pp=307–312}}</ref> The modern scientist [[John Desmond Bernal|John Bernal]] said that the basic idea of such theories was that life was continuously created as a result of chance events.<ref name="Bernal 1967">{{harvnb|Bernal|1967}}</ref><br />
<br />
传统宗教把生命的起源归结为超自然的神灵,他们创造了自然界。“自然发生”,是第一个从非生命中产生生命的自然主义理论,它可以追溯到Aristotle和古希腊哲学,并在西方学术界一直得到支持,直到19世纪。"自然发生”的古典观念认为,某些 "低等 "或 "害虫 "动物是由腐烂的有机物质产生的。根据Aristotle的观点,很容易观察到蚜虫从植物上的露水中产生,苍蝇从腐烂的物质中产生,老鼠从肮脏的干草中产生,鳄鱼从腐烂的沉木中产生,等等。一个相关的理论是异生论:某些生命形式可以从不同的形式中产生(如蜜蜂从花中产生)。现代科学家约翰·德斯蒙德·贝纳尔John Desmond Bernal说,这种理论的基本思想是生命是作为偶然事件的结果而不断产生的。<br />
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In the 17th century, people began to question such assumptions. In 1646, [[Sir Thomas Browne|Thomas Browne]] published his ''[[Pseudodoxia Epidemica]]'' (subtitled ''Enquiries into Very many Received Tenets, and commonly Presumed Truths''), which was an attack on false beliefs and "vulgar errors." His contemporary, [[Alexander Ross (writer)|Alexander Ross]], erroneously refuted him, stating:<br />
< blockquote > To question this [spontaneous generation], is to question Reason, Sense, and Experience: If he doubts of this, let him go to ''[[Egypt|Ægypt]]'', and there he will find the fields swarming with mice begot of the mud of ''[[Nile|Nylus]]'', to the great calamity of the Inhabitants.<ref>{{cite journal |last=Balme |first=D.M. |authorlink=David Mowbray Balme |year=1962 |title=Development of Biology in Aristotle and Theophrastus: Theory of Spontaneous Generation |journal=[[Phronesis (journal)|Phronesis]] |volume=7 |issue=1–2 |pages=91–104 |doi=10.1163/156852862X00052}}</ref><ref>{{harvnb|Ross|1652}}</ref>< /blockquote ><br />
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在17世纪,人们开始质疑这些假设。1646年,托马斯·布朗爵士 Sir Thomas Browne出版了他的《伪传染病》(副标题为“对许多公认的原则和通常假定的真理的询问”),该书攻击了错误的信念和“庸俗的错误”。与他同时代的亚历山大·罗斯 Alexander Ross错误地驳斥了他,称:<br />
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< blockquote > <br />
质疑这个自然发生,就是质疑理性、感觉和经验。如果他怀疑这一点,让他去埃及, 在那里,他将会发现田野里到处都是由尼罗斯的泥土生出的老鼠,给当地居民带来了巨大的灾难。<br />
< /blockquote > <br />
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[[File:Anton van Leeuwenhoek.png|thumb|upright|Antonie van Leeuwenhoek]]<br />
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安东尼·范·列文虎克<br />
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In 1665, [[Robert Hooke]] published the first drawings of a [[microorganism]]. Hooke was followed in 1676 by [[Antonie van Leeuwenhoek]], who drew and described microorganisms that are now thought to have been [[protozoa]] and [[bacteria]].<ref>{{harvnb|Dobell|1960}}</ref> Many felt the existence of microorganisms was evidence in support of spontaneous generation, since microorganisms seemed too simplistic for [[sexual reproduction]], and [[asexual reproduction]] through [[mitosis|cell division]] had not yet been observed. Van Leeuwenhoek took issue with the ideas common at the time that fleas and lice could spontaneously result from [[putrefaction]], and that frogs could likewise arise from slime. Using a broad range of experiments ranging from sealed and open meat incubation and the close study of insect reproduction he became, by the 1680s, convinced that spontaneous generation was incorrect.<ref>{{harvnb|Bondeson|1999}}</ref><br />
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1665年,罗伯特·胡克Robert Hooke发表了第一本微生物的图画。1676年,安东尼·范·列文虎克(Antonie van Leeuwenhoek)紧随其后,他绘制并描述了现在被认为是原生动物和细菌的微生物。许多人认为微生物的存在是支持自然发生的证据,因为微生物对于有性生殖来说似乎过于简单,而通过细胞分裂的无性生殖尚未被观察到。Van Leeuwenhoek对当时常见的跳蚤和虱子可能由腐烂作用自发产生,以及青蛙同样可能由粘液产生的观点提出了异议。他利用广泛的实验,从密封和开放的肉孵化以及对昆虫繁殖的仔细研究,到1680年代,他确信自然发生是不正确的。<br />
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The first experimental evidence against spontaneous generation came in 1668 when [[Francesco Redi]] showed that no [[maggot]]s appeared in meat when flies were prevented from laying eggs. It was gradually shown that, at least in the case of all the higher and readily visible organisms, the previous sentiment regarding spontaneous generation was false. The alternative hypothesis was ''[[biogenesis]]'': that every living thing came from a pre-existing living thing (''omne vivum ex ovo'', Latin for "every living thing from an egg").<ref name=lev>{{cite web |vauthors=Levine R, Evers C |title=The Slow Death of Spontaneous Generation (1668-1859) |url=http://www.accessexcellence.org/RC/AB/BC/Spontaneous_Generation.php |accessdate=18 April 2013 |url-status=dead |archiveurl=https://web.archive.org/web/20080426191204/http://www.accessexcellence.org/RC/AB/BC/Spontaneous_Generation.php |archivedate=26 April 2008 }}</ref> In 1768, [[Lazzaro Spallanzani]] demonstrated that [[microorganism|microbes]] were present in the air, and could be killed by boiling. In 1861, [[Louis Pasteur]] performed a series of experiments that demonstrated that organisms such as bacteria and fungi do not spontaneously appear in sterile, nutrient-rich media, but could only appear by invasion from without.<br />
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第一个反对自然发生的实验证据是在1668年,当时弗朗西斯科·雷迪 Francesco Redi表明,当阻止苍蝇产卵时,肉中不会出现蛆虫。人们逐渐发现,至少在所有高等和易见生物的情况下,以前关于自发生成的观点是错误的。另一种假设是“生源论”:每个生物都来自一个已经存在的生物(“ omne vivum ex ovo”,拉丁语的意思是“每个生物来自于一个蛋”)。1768年,拉扎罗·斯帕兰扎尼(Lazzaro Spallanzani)证明了空气中存在微生物,并且可以通过煮沸杀死。1861年,路易·巴斯德 Louis Pasteur进行了一系列实验,证明细菌和真菌等生物在无菌、营养丰富的培养基中不会自发出现,只能通过从外部入侵出现。<br />
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====Spontaneous generation considered disproven in the 19th century====<br />
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自然发生论在19世纪被认为是不成立的。<br />
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[[File:Louis Pasteur, foto av Paul Nadar, Crisco edit.jpg|thumb|upright|left|Louis Pasteur]]<br />
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路易斯·巴斯德(Louis Pasteur)<br />
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[[File:Darwin restored2.jpg|thumb|upright|alt=Head and shoulders portrait, increasingly bald with rather uneven bushy white eyebrows and beard, his wrinkled forehead suggesting a puzzled frown|[[Charles Darwin]] in 1879]]<br />
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查尔斯·达尔文 Charles Darwin(1879年)<br />
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By the middle of the 19th century, biogenesis had accumulated so much evidence in support that the alternative theory of spontaneous generation had been effectively disproven. [[Louis Pasteur|Pasteur]] remarked, about a finding of his in 1864 which he considered definitive, < blockquote >Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.<ref>{{harvnb|Oparin|1953|p=196}}</ref><ref name="Tyndall Fragments2">{{harvnb|Tyndall|1905|loc=IV, XII (1876), XIII (1878)}}</ref> < /blockquote >gave a mechanism by which life diversified from a few simple organisms to a variety of to complex forms. Today, scientists agree that all current life descends from earlier life, which has become progressively more complex and diverse through [[Charles Darwin]]'s mechanism of [[evolution]] by [[natural selection]].<br />
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Darwin wrote to Hooker in 1863 stating that, < blockquote >It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter.< /blockquote > In ''[[On the Origin of Species]]'', he had referred to life having been "created", by which he "really meant 'appeared' by some wholly unknown process", but had soon regretted using the Old Testament term "creation".{{Citation needed|date=July 2020}}<br />
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到19世纪中叶,生源论已经积累了大量的证据,以至于自然发生的替代理论已经被有效地否定。Pasteur评论道,他在1864年的一项发现被他认为是决定性的:<br />
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< blockquote ><br />
自然发生的学说永远不会从这个简单的实验所带来的致命打击中恢复过来。<br />
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实验给出了一个机制,通过这个机制,生命从几个简单的生物体多样化到各种复杂的形式。今天,科学家们一致认为,目前所有的生命都是早期生命的后裔,而早期生命通过Charles Darwin的自然选择进化机制,逐渐变得更加复杂和多样化。Darwin在1863年给Hooker写信指出:<br />
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< blockquote ><br />
目前思考生命的起源纯粹是垃圾,还不如思考物质的起源。<br />
< blockquote ><br />
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在《物种起源》中,他曾提到生命是 "被创造的",他说生命是“被创造出来的”,“实际上是指通过某种完全未知的过程‘出现’”,但很快就后悔使用《旧约》中的“创造”一词。<br />
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==== Etymology of biogenesis and abiogenesis====<br />
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生源论(生物起源)和非生源论(非生物起源)的词源学<br />
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<!--This section is the for topic in general, so the following timeline of specific molecule discovery seems out of place:<br />
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< ! ——这一部分是一般的主题,所以下面的具体分子发现时间线似乎不合适:<br />
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{{Main|Biogenesis}}<br />
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The term ''biogenesis'' is usually credited to either [[Henry Charlton Bastian|Henry Bastian]] or to [[Thomas Henry Huxley|Thomas Huxley]].<ref name="eohtBiogenesis">{{cite encyclopedia |encyclopedia=Hmolpedia |title=Biogenesis |url=http://www.eoht.info/page/Biogenesis |accessdate=2014-05-19 |publisher=WikiFoundry, Inc. |location=Ancaster, Ontario, Canada |url-status=live |archiveurl=https://web.archive.org/web/20140520001148/http://www.eoht.info/page/Biogenesis |archivedate=20 May 2014}}</ref> Bastian used the term around 1869 in an unpublished exchange with [[John Tyndall]] to mean "life-origination or commencement". In 1870, Huxley, as new president of the [[British Science Association|British Association for the Advancement of Science]], delivered an address entitled ''Biogenesis and Abiogenesis''.<ref name="Huxley 1968">{{harvnb|Huxley|1968}}</ref> In it he introduced the term ''biogenesis'' (with an opposite meaning to Bastian's) as well as ''abiogenesis'':<br />
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生物起源一词通常归功于亨利·巴斯蒂安Henry Bastian或托马斯·赫胥黎Thomas Huxley.。Bastian大约在1869年与约翰·廷德尔John Tyndall的一次未发表的交流中使用了这个词,意思是“生命-起源或开始”。1870年,Huxley作为英国科学促进会的新任主席,发表了题为《生物起源和非生物起源》的演讲。在演讲中,他介绍了“生物起源”(与Bastian的意思相反)以及“非生物起源”这个术语。<br />
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:And thus the hypothesis that living matter always arises by the agency of pre-existing living matter, took definite shape; and had, henceforward, a right to be considered and a claim to be refuted, in each particular case, before the production of living matter in any other way could be admitted by careful reasoners. It will be necessary for me to refer to this hypothesis so frequently, that, to save circumlocution, I shall call it the hypothesis of ''Biogenesis''; and I shall term the contrary doctrine—that living matter may be produced by not living matter—the hypothesis of ''Abiogenesis''.<ref name="Huxley 1968" /><br />
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因此,关于生命物质总是经由先前存在的生命物质产生的假说,就有了明确的形式;并且,从今以后,在仔细的推理者能够承认以任何其他方式产生生命物质之前,在每一个特定的情况下,都有被考虑和被驳斥的权利。我有必要经常提到这个假说,所以,为了节省周折,我将把它称为“生物起源论”的假说;而我将把相反的学说--有生命的物质可能由无生命的物质产生--称为“非生物起源论”的假说。<br />
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--><br />
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--><br />
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Subsequently, in the preface to Bastian's 1871 book, ''The Modes of Origin of Lowest Organisms'',<ref>{{harvnb|Bastian|1871}}</ref> Bastian referred to the possible confusion with Huxley's usage and explicitly renounced his own meaning:<br />
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随后,在Bastian1871年出版的《最低级生物的起源模式》一书的序言中,Bastian提到了可能与Huxley的用法相混淆,并明确放弃了自己的意思。<br />
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:A word of explanation seems necessary with regard to the introduction of the new term ''Archebiosis''. I had originally, in unpublished writings, adopted the word ''Biogenesis'' to express the same meaning—viz., life-origination or commencement. But in the meantime, the word ''Biogenesis'' has been made use of, quite independently, by a distinguished biologist [Huxley], who wished to make it bear a totally different meaning. He also introduced the word ''Abiogenesis''. I have been informed, however, on the best authority, that neither of these words can—with any regard to the language from which they are derived—be supposed to bear the meanings which have of late been publicly assigned to them. Wishing to avoid all needless confusion, I therefore renounced the use of the word ''Biogenesis'', and being, for the reason just given, unable to adopt the other term, I was compelled to introduce a new word, in order to designate the process by which living matter is supposed to come into being, independently of pre-existing living matter.<ref>{{harvnb|Bastian|1871|p=[https://ia902701.us.archive.org/BookReader/BookReaderImages.php?zip=/23/items/modesoforiginofl00bast/modesoforiginofl00bast_jp2.zip&file=modesoforiginofl00bast_jp2/modesoforiginofl00bast_0015.jp2&scale=4&rotate=0 xi–xii]}}</ref><br />
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Since the end of the nineteenth century, 'evolutive abiogenesis' means increasing complexity and evolution of matter from inert to living states.<ref>[https://link.springer.com/referenceworkentry/10.1007/978-3-642-27833-4_2-4 Abiogenesis – Definition]. 20 April 2015. ''Encyclopedia of Astrobiology''. {{doi|10.1007/978-3-642-27833-4_2-4}}</ref><br />
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关于新术语 "生物自生 "的引入,似乎有必要作一解释。我最初在未发表的著作中,采用了 "生物起源 "一词来表达同样的意思,即生命的起源或开始。但与此同时,“生物起源”这个词已经被一位杰出的生物学家Huxley独立地使用了,他希望使它具有完全不同的意义。他还介绍了“非生物起源”这个词。然而,我从最权威的人士那里得知,这些词无论它们来自什么语言,都不应具有最近公开赋予它们的含义。为了避免一切不必要的混淆,我因此放弃了使用 "生物起源 "这个词,而且由于刚才所讲的原因,我无法采用另一个词,我不得不引入一个新词,以便指定生命物质被认为是独立于先前存在的生命物质而产生的过程。<br />
自19世纪末以来,'演化性非生物起源'是指物质从惰性状态到生命状态的复杂性和演化性的增加。<br />
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=== Oparin: Primordial soup hypothesis ===<br />
奥帕林 Oparin:原始汤假说<br />
{{Main|Primordial soup}}<br />
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{{further|Miller–Urey experiment}}<br />
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There is no single generally accepted model for the origin of life. Scientists have proposed several plausible hypotheses which share some common elements. While differing in details, these hypotheses are based on the framework laid out by [[Alexander Oparin]] (in 1924) and [[J. B. S. Haldane|John Haldane]] (in 1925), that the first molecules constituting the earliest cells < blockquote >. . . were synthesized under natural conditions by a slow process of molecular evolution, and these molecules then organized into the first molecular system with properties with biological order".<ref name="bah2">{{cite journal|last=Bahadur|first=Krishna|year=1973|title=Photochemical Formation of Self–sustaining Coacervates|url=http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|url-status=dead|journal=Proceedings of the Indian National Science Academy|volume=39B|issue=4|pages=455–467|doi=10.1016/S0044-4057(75)80076-1|pmid=1242552|archiveurl=https://web.archive.org/web/20131019172800/http://www.dli.gov.in/rawdataupload/upload/insa/INSA_1/20005b73_455.pdf|archivedate=19 October 2013}}<br />
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对于生命的起源,没有一个普遍接受的模式。科学家们提出了几种似乎可信的假说,这些假说有一些共同的内容。这些假说虽然在细节上有所不同,但都是基于亚历山大·奥帕林Alexander Oparin(1924年)和约翰·霍尔丹John Haldane(1925年)提出的框架,即构成最早的细胞的第一批分子。<br />
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< blockquote ><br />
...是在自然条件下通过缓慢的分子进化过程合成的,然后这些分子组成第一个具有生物秩序特性的分子系统"。<br />
< blockquote ><br />
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* {{cite journal|last=Bahadur|first=Krishna|year=1975|title=Photochemical Formation of Self-Sustaining Coacervates|journal=[[Microbiological Research|Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene]]|volume=130|issue=3|pages=211–218|doi=10.1016/S0044-4057(75)80076-1|oclc=641018092|pmid=1242552}}</ref> < /blockquote >Oparin and Haldane suggested that the atmosphere of the early Earth may have been chemically reducing in nature, composed primarily of methane (CH<sub>4</sub>), ammonia (NH<sub>3</sub>), water (H<sub>2</sub>O), hydrogen sulfide (H<sub>2</sub>S), carbon dioxide (CO<sub>2</sub>) or carbon monoxide (CO), and [[phosphate]] (PO<sub>4</sub><sup>3−</sup>), with molecular oxygen (O<sub>2</sub>) and [[ozone]] (O<sub>3</sub>) either rare or absent. According to later models, the atmosphere in the late Hadean period consisted largely of nitrogen (N<sub>2</sub>) and carbon dioxide, with smaller amounts of carbon monoxide, hydrogen (H<sub>2</sub>), and sulfur compounds;<ref>{{harvnb|Kasting|1993|p=922}}</ref> while it did lack molecular oxygen and ozone,<ref>{{harvnb|Kasting|1993|p=920}}</ref> it was not as chemically reducing as Oparin and Haldane supposed.<br />
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Oparin和Haldane提出,早期地球的大气可能具有化学还原性,主要由甲烷(CH<sub>4</sub>)、氨(NH<sub>3</sub>)、水(H<sub>2</sub>O)、硫化氢(H<sub>2</sub>S、二氧化碳(CO<sub>2</sub>)或一氧化碳(CO)和磷酸盐(PO<sub>4</sub><sup>3−</sup>)组成,分子氧(O<sub>2</sub>)和臭氧(O<sub>3</sub>)很少或没有。根据后来的模型,冥古代晚期的大气主要由氮气(N<sub>2</sub>)和二氧化碳组成,还有少量的一氧化碳、氢气(H<sub>2</sub>)和硫磺化合物;虽然它确实缺乏分子氧和臭氧,但它并不像Oparin和Haldane所认为的那样具有化学还原性。<br />
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No new notable research or hypothesis on the subject appeared until 1924, when Oparin reasoned that atmospheric oxygen prevents the synthesis of certain organic compounds that are necessary building blocks for life. In his book ''The Origin of Life'',<ref>{{harvnb|Bernal|1967|loc=[http://www.valencia.edu/~orilife/textos/The%20Origin%20of%20Life.pdf ''The Origin of Life'' (A.I. Oparin, 1924), pp. 199–234]}}</ref><ref>{{harvnb|Oparin|1953}}</ref> he proposed (echoing Darwin) that the "spontaneous generation of life" that had been attacked by Pasteur did, in fact, occur once, but was now impossible because the conditions found on the early Earth had changed, and preexisting organisms would immediately consume any spontaneously generated organism. Oparin argued that a "primeval soup" of organic molecules could be created in an oxygenless atmosphere through the action of [[sunlight]]. These would combine in ever more complex ways until they formed [[coacervate]] droplets. These droplets would "[[cell growth|grow]]" by fusion with other droplets, and "[[reproduction|reproduce]]" through fission into daughter droplets, and so have a primitive [[metabolism]] in which factors that promote "cell integrity" survive, and those that do not become [[Extinction|extinct]]. Many modern theories of the origin of life still take Oparin's ideas as a starting point.<br />
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直到1924年,才出现了关于这个问题的新的著名研究或假说,Oparin推理出大气中的氧气阻碍了某些有机化合物的合成,而这些有机化合物是生命的必要构件。在他的《生命的起源》一书中,他提出(与Darwin相呼应),被Pasteur抨击的 "生命的自然发生"事实上确实曾经发生过,但现在是不可能的,因为早期地球上发现的条件已经发生了变化,先前存在的生物体会立即消耗任何自发产生的生物体。Oparin认为,在无氧的大气中,通过太阳光的作用,可以产生有机分子的 "原始汤"。这些分子会以越来越复杂的方式结合在一起,直到形成凝聚的液滴。这些液滴会通过与其他液滴的融合而"生长",并通过裂变"繁殖"成子液滴,因此具有原始的新陈代谢,在这种新陈代谢中,能促进 "细胞完整性"的因子得以生存,而不能促进的因子则会灭绝。现代许多关于生命起源的理论仍然以Oparin的思想为出发点。<br />
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About this time, Haldane suggested that the Earth's prebiotic oceans (quite different from their modern counterparts) would have formed a "hot dilute soup" in which organic compounds could have formed. Bernal called this idea ''biopoiesis'' or ''biopoesis'', the process of living matter evolving from self-replicating but non-living molecules,<ref name="Bernal 1967" /><ref>{{harvnb|Bryson|2004|pp=300–302}}</ref> and proposed that biopoiesis passes through a number of intermediate stages.<br />
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大约在这个时候,Haldane提出,地球上的前生物海洋(与现代的同类海洋截然不同)会形成一种 "热稀汤",有机化合物可能在其中形成。Bernal将这一观点称为“生物创建”或“生物创造”,即有生命的物质从自我复制但无生命的分子中演化出来的过程,并提出生物创建经过许多中间阶段。<br />
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[[Robert Shapiro (chemist)|Robert Shapiro]] has summarized the "primordial soup" theory of Oparin and Haldane in its "mature form" as follows:<ref>{{harvnb|Shapiro|1987|p=110}}</ref><br />
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罗伯特·夏皮罗Robert Shapiro将Oparin和Haldane的 "原始汤"理论的 "成熟形态 "总结如下:<br />
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# The early Earth had a chemically [[reducing atmosphere]].<br />
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早期的地球有一个化学还原的大气层。<br />
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# This atmosphere, exposed to [[energy]] in various forms, produced simple organic compounds ("[[monomer]]s").<br />
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这种大气层暴露在各种形式的能量之下,产生了简单的有机化合物("单质")。<br />
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# These compounds accumulated in a "soup" that may have concentrated at various locations (shorelines, [[Hydrothermal vent|oceanic vents]] etc.).<br />
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这些化合物积聚在 "汤 "中,可能集中在不同的地点(海岸线、海洋喷口等)。<br />
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# By further transformation, more complex organic [[polymer]]s—and ultimately life—developed in the soup.<br />
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通过进一步的转化,更复杂的有机聚合物--最终在汤中发展出生命。<br />
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===John Bernal===<br />
约翰•伯纳尔<br />
John Bernal showed that based upon this and subsequent work there is no difficulty in principle in forming most of the molecules we recognize as the necessary molecules for life from their inorganic precursors. The underlying hypothesis held by Oparin, Haldane, Bernal, Miller and Urey, for instance, was that multiple conditions on the primeval Earth favoured chemical reactions that synthesized the same set of complex organic compounds from such simple precursors. <br />
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John Bernal 表明,基于这一研究和随后的工作,从无机前体中形成我们所认识到的生命所必需的大部分分子原则上没有困难。例如,Oparin、Haldane、Bernal、Miller和Urey所持的基本假设是,原始地球上的多种条件有利于化学反应从这些简单的前体合成同一组复杂的有机化合物。<br />
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Bernal coined the term ''biopoiesis'' in 1949 to refer to the origin of life.<ref>{{harvnb|Bernal|1951}}</ref> In 1967, he suggested that it occurred in three "stages":<br />
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Bernal在1949年创造了“生物创建”这一术语,用来指代生命的起源。1967年,他提出生命的起源是分三个 "阶段 "发生的。<br />
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# the origin of biological monomers<br />
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生物单体的起源<br />
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# the origin of biological polymers<br />
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生物聚合物的起源<br />
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# the evolution from molecules to cells<br />
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从分子到细胞的演变<br />
<br />
Bernal suggested that evolution commenced between stages 1 and 2. Bernal regarded the third stage, in which biological reactions were incorporated behind a cell's boundary, as the most difficult. Modern work on the way that [[cell membrane]]s self-assemble, and the work on micropores in various substrates, may be a key step towards understanding the development of independent free-living cells.<ref>{{cite journal |last= Martin |first= William F. |authorlink= William F. Martin |date= January 2003 |title= On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells |journal=Phil. Trans. R. Soc. Lond. A |volume= 358 |issue= 1429 |pages= 59–83 |doi= 10.1098/rstb.2002.1183 |pmid=12594918 |pmc=1693102}}</ref><ref>{{cite journal |last= Bernal |first= John Desmond |authorlink= John Desmond Bernal |date= September 1949 |title= The Physical Basis of Life |journal= Proceedings of the Physical Society, Section A |volume= 62 |issue= 9 |pages= 537–558 |bibcode= 1949PPSA...62..537B |doi= 10.1088/0370-1298/62/9/301 }}</ref><ref>{{harvnb|Kauffman|1995}}</ref><br />
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Bernal认为,进化始于第一和第二阶段之间。Bernal认为第三阶段是最困难的阶段,在这一阶段,生物反应被纳入细胞的边界之后。现代对细胞膜自组装方式的研究,以及对各种基质中微孔的研究,可能是理解独立自主生活细胞发展的关键一步。<br />
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===Miller–Urey experiment===<br />
<br />
米勒-乌雷实验<br />
<br />
[[File:Miller1999.jpg|thumb|left|upright|Stanley Miller]]<br />
<br />
斯坦利·米勒<br />
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[[File:Miller-Urey.jpg|thumb|upright=1.5|Miller–Urey experiment JP]] <br />
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Miller–Urey实验JP<br />
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One of the most important pieces of experimental support for the "soup" theory came in 1952. [[Stanley L. Miller|Stanley Miller]] and [[Harold C. Urey|Harold Urey]] performed an experiment that demonstrated how organic molecules could have spontaneously formed from inorganic precursors under conditions like those posited by the Oparin-Haldane hypothesis. The now-famous [[Miller–Urey experiment]] used a highly reducing mixture of gases—[[methane]], [[ammonia]], and [[hydrogen gas|hydrogen]], as well as [[water vapor]]—to form simple organic monomers such as amino acids.<ref>{{cite journal |last=Miller |first=Stanley L. |authorlink=Stanley Miller |date=15 May 1953 |title=A Production of Amino Acids Under Possible Primitive Earth Conditions |journal=[[Science (journal)|Science]] |volume=117 |issue=3046 |pages=528–529 |bibcode=1953Sci...117..528M |doi=10.1126/science.117.3046.528 |pmid=13056598}}</ref> The mixture of gases was cycled through an apparatus that delivered electrical sparks to the mixture. After one week, it was found that about 10% to 15% of the carbon in the system was then in the form of a [[racemic mixture]] of organic compounds, including amino acids, which are the building blocks of [[protein]]s. This provided direct experimental support for the second point of the "soup" theory, and it is around the remaining two points of the theory that much of the debate now centers.<br />
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“汤 ”理论最重要的实验支持之一是在1952年。Stanley Miller和Harold Urey做了一个实验,证明了在类似Oparin-Haldane假说所提出的条件下,有机分子是如何从无机前体自发形成的。现在著名的Miller-Urey实验使用高度还原性的混合气体--甲烷、氨、氢以及水蒸气—来形成简单的有机单体,如氨基酸。混合气体通过一个装置循环,将电火花传递到混合物中。一周后,发现系统中约有10%至15%的碳以有机化合物的外消旋混合物的形式存在,其中包括氨基酸,而氨基酸是蛋白质的构件。这为 "汤 "理论的第二点提供了直接的实验支持,而现在很多争论的焦点正是围绕着该理论的其余两点。<br />
<br />
A 2011 reanalysis of the saved vials containing the original extracts that resulted from the Miller and Urey experiments, using current and more advanced analytical equipment and technology, has uncovered more biochemicals than originally discovered in the 1950s. One of the more important findings was 23 amino acids, far more than the five originally found.<ref name="pmid21422282">{{cite journal |last1=Parker |first1=Eric T. |last2=Cleaves |first2=Henderson J. |last3=Dworkin |first3=Jason P. |last4=Glavin |first4=Daniel P. |last5=Callahan |first5=Michael |last6=Aubrey |first6=Andrew |last7=Lazcano |first7=Antonio |last8=Bada |first8=Jeffrey L. |display-authors=3 |date=5 April 2011 |title=Primordial synthesis of amines and amino acids in a 1958 Miller H<sub>2</sub>S-rich spark discharge experiment |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=108 |issue=14 |pages=5526–5531 |bibcode=2011PNAS..108.5526P |doi=10.1073/pnas.1019191108 |pmc=3078417 |pmid=21422282 }}</ref><br />
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2011年,利用目前更先进的分析设备和技术,对Miller和Urey实验产生的含有原始提取物的保存瓶进行了重新分析,发现了比20世纪50年代最初发现的更多的生化物质。其中比较重要的发现是23种氨基酸,远远超过原来发现的5种。<br />
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== Primordial origin of biological molecules: Chemistry ==<br />
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生物分子的原始起源: 化学 <br />
<br />
The chemical processes on the pre-biotic early Earth are called [[chemical evolution (disambiguation)|''chemical evolution'']]. <br />
The [[Chemical element|elements]], except for hydrogen and helium, ultimately derive from [[stellar nucleosynthesis]]. In 2016, astronomers reported that the very basic chemical ingredients of [[life]]—the [[Carbon-hydrogen bond|carbon-hydrogen molecule]] (CH, or [[methylidyne radical]]), the carbon-hydrogen positive ion (CH+) and the carbon ion (C+)—are largely the result of [[ultraviolet light]] from stars, rather than other forms of radiation from [[supernovae]] and [[young star]]s, as thought earlier.<ref name="NASA-20161012">{{cite web |last=Landau |first=Elizabeth |title=Building Blocks of Life's Building Blocks Come From Starlight |url=http://www.jpl.nasa.gov/news/news.php?feature=6645 |date=12 October 2016 |work=[[NASA]] |accessdate=13 October 2016 |url-status=live |archiveurl=https://web.archive.org/web/20161013135018/http://www.jpl.nasa.gov/news/news.php?feature=6645 |archivedate=13 October 2016}}</ref> Complex molecules, including organic molecules, form naturally both in space and on planets.<ref name="Ehrenfreund2010" /> There are two possible sources of organic molecules on the early Earth:<br />
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生物前的早期地球的化学过程称为“化学进化”。除氢和氦外,其他元素最终都来自于恒星核合成。2016年,天文学家报告说,生命的非常基本的化学成分--碳氢分子(CH,或称次甲基自由基)、碳氢正离子(CH+)和碳离子(C+)--主要是来自恒星的紫外线的结果,而不是之前认为的来自超新星和年轻恒星的其他辐射形式。复杂的分子,包括有机分子,在太空和行星上自然形成。早期地球上的有机分子有两种可能的来源:<br />
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# Terrestrial origins – organic molecule synthesis driven by impact shocks or by other energy sources (such as UV light, [[Organic redox reaction|redox]] coupling, or electrical discharges; e.g., Miller's experiments)<br />
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地球起源 -- -- 撞击冲击或其他能量源(如紫外光、氧化还原耦合或放电;如,Miller的实验)驱动的有机分子合成。<br />
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# Extraterrestrial origins – formation of organic molecules in [[Interstellar cloud|interstellar dust clouds]], which rain down on planets.<ref name="Gawlowicz 2011">{{cite news |last=Gawlowicz |first=Susan |date=6 November 2011 |title=Carbon-based organic 'carriers' in interstellar dust clouds? Newly discovered diffuse interstellar bands |url=https://www.sciencedaily.com/releases/2011/11/111102161149.htm |work=[[Science Daily]] |location=Rockville, MD |publisher=ScienceDaily, LLC |accessdate=2015-06-08 |url-status=live |archiveurl=https://web.archive.org/web/20150711114643/https://www.sciencedaily.com/releases/2011/11/111102161149.htm |archivedate=11 July 2015}} Post is reprinted from materials provided by the [[Rochester Institute of Technology]].<br />
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地外起源--星际尘埃云中有机分子的形成,这些尘埃云降到行星上。<br />
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=== Observed extraterrestrial organic molecules ===<br />
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观察到的地外有机分子<br />
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{{See also|List of interstellar and circumstellar molecules|Panspermia#Pseudo-panspermia}}<br />
<br />
An organic compound is any member of a large class of gaseous, liquid, or solid chemicals whose molecules contain carbon. Carbon is the [[Abundance of the chemical elements|fourth most abundant element in the Universe by mass]] after hydrogen, [[helium]], and oxygen.<ref>{{cite encyclopedia |encyclopedia=Encyclopedia of Science |title=biological abundance of elements |url=http://www.daviddarling.info/encyclopedia/E/elbio.html |publisher=David Darling Enterprises |location=Dundee, Scotland |accessdate=2008-10-09 |url-status=live |archiveurl=https://web.archive.org/web/20120204033420/http://www.daviddarling.info/encyclopedia/E/elbio.html |archivedate=4 February 2012}}</ref> Carbon is abundant in the Sun, stars, comets, and in the [[Celestial body's atmosphere|atmospheres]] of most planets.<ref name="NASA-20140221">{{cite web |url=http://www.nasa.gov/ames/need-to-track-organic-nano-particles-across-the-universe-nasas-got-an-app-for-that/ |title=Need to Track Organic Nano-Particles Across the Universe? NASA's Got an App for That |last=Hoover |first=Rachel |date=21 February 2014 |website=[[Ames Research Center]] |publisher=NASA |location=Mountain View, CA |accessdate=2015-06-22 |url-status=live |archiveurl=https://web.archive.org/web/20150906061428/http://www.nasa.gov/ames/need-to-track-organic-nano-particles-across-the-universe-nasas-got-an-app-for-that/ |archivedate=6 September 2015}}</ref> Organic compounds are relatively common in space, formed by "factories of complex molecular synthesis" which occur in [[molecular cloud]]s and [[circumstellar envelope]]s, and chemically evolve after reactions are initiated mostly by [[ionizing radiation]].<ref name="Ehrenfreund2010">{{cite journal |last1=Ehrenfreund |first1=Pascale |last2=Cami |first2=Jan |date=December 2010 |title=Cosmic carbon chemistry: from the interstellar medium to the early Earth. |journal=Cold Spring Harbor Perspectives in Biology |volume=2 |issue=12 |page=a002097 |doi=10.1101/cshperspect.a002097 |pmc=2982172 |pmid=20554702}}</ref><ref name="FromADistantComet">{{cite news |last=Chang |first=Kenneth |date=18 August 2009 |title=From a Distant Comet, a Clue to Life |url=https://www.nytimes.com/2009/08/19/science/space/19comet.html |newspaper=The New York Times |location=New York |page=A18 |accessdate=2015-06-22 |url-status=live |archiveurl=https://web.archive.org/web/20150623005046/http://www.nytimes.com/2009/08/19/science/space/19comet.html |archivedate=23 June 2015}}</ref><ref>{{cite journal |last1=Goncharuk |first1=Vladislav V. |last2=Zui |first2=O. V. |date=February 2015 |title=Water and carbon dioxide as the main precursors of organic matter on Earth and in space |journal=Journal of Water Chemistry and Technology |volume=37 |issue=1 |pages=2–3 |doi=10.3103/S1063455X15010026 |s2cid=97965067 }}</ref><ref>{{cite journal |last1=Abou Mrad |first1=Ninette |last2=Vinogradoff |first2=Vassilissa |last3=Duvernay |first3=Fabrice |last4=Danger |first4=Grégoire |last5=Theulé |first5=Patrice |last6=Borget |first6=Fabien |last7=Chiavassa |first7=Thierry |display-authors=3 |year=2015 |title=Laboratory experimental simulations: Chemical evolution of the organic matter from interstellar and cometary ice analogs |url=http://popups.ulg.ac.be/0037-9565/index.php?id=4621&file=1|journal=Bulletin de la Société Royale des Sciences de Liège |volume=84 |pages=21–32 |bibcode=2015BSRSL..84...21A |accessdate=2015-04-06 |url-status=live |archiveurl=https://web.archive.org/web/20150413050621/http://popups.ulg.ac.be/0037-9565/index.php?id=4621&file=1 |archivedate=13 April 2015}}</ref> Based on [[computer simulation|computer model studies]], the complex organic molecules necessary for life may have formed on dust grains in the protoplanetary disk surrounding the Sun before the formation of the Earth.<ref name="Space-20120329" /> According to the computer studies, this same process may also occur around other stars that acquire planets.<ref name="Space-20120329" /><br />
<br />
有机化合物是指分子中含有碳的一大类气态、液态或固态化学物质的任何成员。按质量计算,碳是宇宙中仅次于氢、氦和氧的第四大丰富元素。碳在太阳、恒星、彗星和大多数行星的大气层中含量丰富。有机化合物在太空中比较常见,是由分子云和环星包层中出现的 "复杂分子合成工厂"形成的,主要由电离辐射引发反应后发生化学演变。 根据计算机模型研究,在地球形成之前,生命所需的复杂有机分子可能已经在太阳周围原行星盘的尘粒上形成。根据计算机研究,这一过程也可能发生在其他获得行星的恒星周围。<br />
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====Amino acids====<br />
氨基酸<br />
NASA announced in 2009 that scientists had identified another fundamental chemical building block of life in a comet for the first time, glycine, an amino acid, which was detected in material ejected from comet [[81P/Wild|Wild 2]] in 2004 and grabbed by NASA's [[Stardust (spacecraft)|''Stardust'']] probe. Glycine has been detected in meteorites before. Carl Pilcher, who leads the [[NASA Astrobiology Institute]] commented that < blockquote >The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare.<ref>{{cite news |author=<!--Staff writer(s); no by-line.--> |date=18 August 2009 |title='Life chemical' detected in comet |url=http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |work=BBC News |location=London |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150525071228/http://news.bbc.co.uk/2/hi/science/nature/8208307.stm |archivedate=25 May 2015}}</ref>< /blockquote > Comets are encrusted with outer layers of dark material, thought to be a [[tar]]-like substance composed of complex organic material formed from simple carbon compounds after reactions initiated mostly by ionizing radiation. It is possible that a rain of material from comets could have brought significant quantities of such complex organic molecules to Earth.<ref>{{cite journal |last1=Thompson |first1=William Reid |last2=Murray |first2=B. G. |last3=Khare |first3=Bishun Narain |authorlink3=Bishun Khare |last4=Sagan |first4=Carl |date=30 December 1987 |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: Applications to the outer solar system |journal=[[Journal of Geophysical Research]] |volume=92 |issue=A13 |pages=14933–14947 |bibcode=1987JGR....9214933T |doi=10.1029/JA092iA13p14933 |pmid=11542127}}</ref><ref>{{cite web |url=https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |title=Life on Earth shockingly comes from out of this world |last=Stark |first=Anne M. |date=5 June 2013 |publisher=[[Lawrence Livermore National Laboratory]] |location=Livermore, CA |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150916135630/https://www.llnl.gov/news/life-earth-shockingly-comes-out-world |archivedate=16 September 2015}}</ref><ref>{{cite journal |last1=Goldman |first1=Nir |last2=Tamblyn |first2=Isaac |date=20 June 2013 |title=Prebiotic Chemistry within a Simple Impacting Icy Mixture |journal=[[Journal of Physical Chemistry A]] |volume=117 |issue=24 |pages=5124–5131 |doi=10.1021/jp402976n |pmid=23639050|bibcode=2013JPCA..117.5124G |url=http://nparc.nrc-cnrc.gc.ca/eng/view/fulltext/?id=e89d2ac7-4cf8-40e0-bcc9-3c53f68ed70a }}</ref> Amino acids which were formed extraterrestrially may also have arrived on Earth via comets.<ref name="Follmann2009" /> It is estimated that during the Late Heavy Bombardment, meteorites may have delivered up to five million [[ton]]s of organic prebiotic elements to Earth per year.<ref name="Follmann2009" /><br />
<br />
美国宇航局在2009年宣布,科学家们首次在彗星中发现了生命的另一个基本化学构件--甘氨酸,这是一种氨基酸,在2004年从荒野2号彗星喷出的物质中检测到,并被美国宇航局的 "星尘 "探测器抓取。甘氨酸此前也曾在陨石中被检测到。领导美国宇航局天体生物学研究所的卡尔·皮尔彻Carl Pilcher说。<br />
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在一颗彗星中发现甘氨酸,支持了生命的基本组成构件在太空中普遍存在的观点,并加强了宇宙中的生命可能是常见而非罕见的论点。<br />
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彗星外层包裹着深色物质,被认为是一种焦油状物质,由简单的碳化合物经过主要由电离辐射引发的反应后形成的复杂有机物质组成。彗星的物质雨有可能将大量的这种复杂的有机分子带到地球上。在外星形成的氨基酸也可能通过彗星到达地球。据估计,在晚期重型轰炸期间,陨石每年可能向地球输送多达500万吨的有机前生物元素。<br />
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==== PAH world hypothesis ====<br />
<br />
多环芳烃世界假说 <br />
<br />
{{Main|PAH world hypothesis}}<br />
<br />
[[Polycyclic aromatic hydrocarbon]]s (PAH) are the most common and abundant of the known polyatomic molecules in the [[observable universe]], and are considered a likely constituent of the [[primordial sea]].<ref name="SP-20051018" /><ref name="AJ-20051010" /><ref name="NASA-20110413" /> In 2010, PAHs, have been detected in [[nebula]]e.<ref name="AJL-20101120">{{cite journal |last1=García-Hernández |first1=Domingo. A. |last2=Manchado |first2=Arturo |last3=García-Lario |first3=Pedro |last4=Stanghellini |first4=Letizia |last5=Villaver |first5=Eva |last6=Shaw |first6=Richard A. |last7=Szczerba |first7=Ryszard |last8=Perea-Calderón |first8=Jose Vicente |display-authors=3 |date=20 November 2010 |title=Formation of Fullerenes in H-Containing Planetary Nebulae |journal=The Astrophysical Journal Letters |volume=724 |issue=1 |pages=L39–L43 |arxiv=1009.4357 |bibcode=2010ApJ...724L..39G |doi=10.1088/2041-8205/724/1/L39 |s2cid=119121764 }}</ref><br />
<br />
多环芳烃(PAH)是可观测宇宙中已知的多原子分子中最常见、最丰富的一种,被认为是原始海的一种可能成分。<br />
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--><br />
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[[File:PIA22568-CatsPawNebula-Spitzer-20181023.jpg|thumb|upright=1.3|The [[Cat's Paw Nebula]] lies inside the [[Milky Way Galaxy]] and is located in the [[constellation]] [[Scorpius]].<br>Green areas show regions where radiation from hot stars collided with large molecules and small dust grains called "[[polycyclic aromatic hydrocarbon]]s" (PAHs), causing them to [[fluoresce]].<br>([[Spitzer space telescope]], 2018)]]<br />
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该猫掌星云位于银河系内并位于星座 天蝎座。绿色区域表示来自热星的辐射与大分子和称为“多环芳烃”(PAHs)的小尘埃碰撞而导致发荧光的区域。<br />
(斯皮策太空望远镜,2018)<br />
<br />
Polycyclic aromatic hydrocarbons (PAH) are known to be abundant in the universe,<ref name="SP-20051018">{{cite news |last= Carey |first= Bjorn |date= 18 October 2005 |title= Life's Building Blocks 'Abundant in Space' |url= http://www.space.com/1686-life-building-blocks-abundant-space.html |website= Space.com |location= Watsonville, CA |publisher= [[Imaginova]] |accessdate= 2015-06-23 |url-status= live |archiveurl= https://web.archive.org/web/20150626223942/http://www.space.com/1686-life-building-blocks-abundant-space.html |archivedate= 26 June 2015}}</ref><ref name="AJ-20051010">{{cite journal |last1=Hudgins |first1= Douglas M. |last2=Bauschlicher |first2=Charles W. Jr. |last3=Allamandola |first3=Louis J. |date=10 October 2005 |title=Variations in the Peak Position of the 6.2 μm Interstellar Emission Feature: A Tracer of N in the Interstellar Polycyclic Aromatic Hydrocarbon Population |journal=[[The Astrophysical Journal]] |volume=632 |pages=316–332 |issue=1 |bibcode=2005ApJ...632..316H |doi=10.1086/432495 |citeseerx=10.1.1.218.8786 }}</ref><ref name="NASA-20110413">{{cite web|url=http://amesteam.arc.nasa.gov/Research/cosmic.html |title=Cosmic Distribution of Chemical Complexity |last1=Des Marais |first1=David J. |last2=Allamandola |first2=Louis J. |last3=Sandford |first3=Scott |authorlink3=Scott Sandford |last4=Mattioda |first4=Andrew |last5=Gudipati |first5=Murthy |last6=Roser |first6=Joseph |last7=Bramall |first7=Nathan |last8=Nuevo |first8=Michel |last9=Boersma |first9=Christiaan |last10=Bernstein |first10=Max |last11=Peeters |first11=Els |last12=Cami |first12=Jan |last13=Cook |first13=Jamie Elsila |last14=Dworkin |first14=Jason |display-authors=3 |year=2009 |website=Ames Research Center |publisher=NASA |location=Mountain View, CA |accessdate=2015-06-24 |url-status=dead |archiveurl=https://web.archive.org/web/20140227184503/http://amesteam.arc.nasa.gov/Research/cosmic.html |archivedate=27 February 2014}} See the Ames Research Center 2009 annual team report to the [[NASA Astrobiology Institute]] here {{cite web|url=https://astrobiology.nasa.gov/nai/reports/annual-reports/2009/arc/ |title=Archived copy |accessdate=2015-06-24 |url-status=dead |archiveurl=https://web.archive.org/web/20130301064911/https://astrobiology.nasa.gov/nai/reports/annual-reports/2009/arc/ |archivedate=1 March 2013}}.</ref> including in the [[interstellar medium]], in comets, and in meteorites, and are some of the most complex molecules so far found in space.<ref name="NASA-20140221" /><br />
<br />
众所周知,多环芳烃在宇宙中非常丰富,包括在星际介质、彗星和陨石中,是迄今为止在空间发现的一些最复杂的分子。<br />
<br />
Other sources of complex molecules have been postulated, including extraterrestrial stellar or interstellar origin. For example, from spectral analyses, organic molecules are known to be present in comets and meteorites. In 2004, a team detected traces of PAHs in a nebula.<ref>{{cite conference |last1=Witt |first1=Adolf N. |last2=Vijh |first2=Uma P. |last3=Gordon |first3=Karl D. |date=January 2004 |title=Discovery of Blue Fluorescence by Polycyclic Aromatic Hydrocarbon Molecules in the Red Rectangle |url=https://aas.org/archives/BAAS/v35n5/aas203/189.htm |publisher=[[American Astronomical Society]] |bibcode=2003AAS...20311017W |archiveurl=https://web.archive.org/web/20031219175322/http://www.aas.org/publications/baas/v35n5/aas203/189.htm |archivedate=19 December 2003 |url-status=dead |conference=American Astronomical Society Meeting 203 |location=Atlanta, GA |access-date=16 January 2019 }}</ref> In 2010, another team also detected PAHs, along with fullerenes, in nebulae.<ref name="AJL-20101120" /> The use of PAHs has also been proposed as a precursor to the RNA world in the PAH world hypothesis.<ref>{{Cite journal|last1=d'Ischia|first1=Marco|last2=Manini|first2=Paola|last3=Moracci|first3=Marco|last4=Saladino|first4=Raffaele|last5=Ball|first5=Vincent|last6=Thissen|first6=Helmut|last7=Evans|first7=Richard A.|last8=Puzzarini|first8=Cristina|last9=Barone|first9=Vincenzo|date=2019-08-21|title=Astrochemistry and Astrobiology: Materials Science in Wonderland?|journal=International Journal of Molecular Sciences|volume=20|issue=17|pages=4079|doi=10.3390/ijms20174079|issn=1422-0067|pmc=6747172|pmid=31438518}}</ref> The [[Spitzer Space Telescope]] has detected a star, HH 46-IR, which is forming by a process similar to that by which the Sun formed. In the disk of material surrounding the star, there is a very large range of molecules, including cyanide compounds, [[hydrocarbon]]s, and carbon monoxide. In 2012, NASA scientists reported that PAHs, subjected to interstellar medium conditions, are transformed, through [[hydrogenation]], [[Oxygenate|oxygenation]] and [[hydroxylation]], to more complex organics—"a step along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively."<ref name="Space-20120920">{{cite web |url= http://www.space.com/17681-life-building-blocks-nasa-organic-molecules.html |title= NASA Cooks Up Icy Organics to Mimic Life's Origins |date= 20 September 2012 |website= Space.com |location= Ogden, UT |publisher= Purch |accessdate= 2015-06-26 |url-status= live |archiveurl= https://web.archive.org/web/20150625035023/http://www.space.com/17681-life-building-blocks-nasa-organic-molecules.html |archivedate= 25 June 2015}}</ref><ref name="AJL-20120901">{{cite journal |last1=Gudipati |first1=Murthy S. |author2=Rui Yang |date=1 September 2012 |title=In-situ Probing of Radiation-induced Processing of Organics in Astrophysical Ice Analogs – Novel Laser Desorption Laser Ionization Time-of-flight Mass Spectroscopic Studies |journal=The Astrophysical Journal Letters |volume=756 |issue=1 |bibcode=2012ApJ...756L..24G |doi=10.1088/2041-8205/756/1/L24 |pages=L24}}</ref> Further, as a result of these transformations, the PAHs lose their [[Spectroscopy|spectroscopic signature]] which could be one of the reasons "for the lack of PAH detection in [[interstellar ice]] grains, particularly the outer regions of cold, dense clouds or the upper molecular layers of protoplanetary disks."<ref name="Space-20120920" /><ref name="AJL-20120901" /><br />
<br />
复杂分子的其他来源也被推测出来,包括地外恒星或星际起源。例如,根据光谱分析,已知有机分子存在于彗星和陨石中。2004年,一个团队在一个星云中检测到了多环芳烃的痕迹。2010年,另一个团队也在星云中检测到了多环芳烃以及富勒烯。"多环芳烃世界"假说中还提出将多环芳烃作为RNA世界的前导。斯皮策太空望远镜探测到一颗恒星HH 46-IR,它的形成过程与太阳的形成过程相似。在恒星周围的物质盘中,有非常多的分子,包括氰化合物、碳氢化合物和一氧化碳。2012年,美国宇航局的科学家报告说,多环芳烃在星际介质条件下,通过氢化、氧化和羟基化,转化为更复杂的有机物--"分别是向氨基酸和核苷酸(蛋白质和DNA的原料)道路上迈进的一步。 "此外,由于这些转化,多环芳烃失去了它们的光谱特征,这可能是 "星际冰粒,特别是寒冷的稠密云的外部区域或原行星盘的上层分子层中,缺乏检测到多环芳烃的原因之一。"<br />
<br />
NASA maintains a database for tracking PAHs in the universe.<ref name="NASA-20140221" /><ref>{{cite web |url=http://www.astrochem.org/pahdb/ |title=NASA Ames PAH IR Spectroscopic Database |publisher=NASA |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150629185734/http://www.astrochem.org/pahdb/ |archivedate=29 June 2015}}</ref> More than 20% of the carbon in the universe may be associated with PAHs,<ref name="NASA-20140221" /><ref name="NASA-20140221" /> possible starting materials for the formation of life. PAHs seem to have been formed shortly after the Big Bang, are widespread throughout the universe,<ref name="SP-20051018" /><ref name="AJ-20051010" /><ref name="NASA-20110413" /> and are associated with [[Star formation|new stars]] and [[exoplanet]]s.<ref name="NASA-20140221" /><br />
<br />
美国宇航局维护着一个追踪宇宙中多环芳烃的数据库。宇宙中超过20%的碳可能与多环芳烃有关,可能是生命形成的起始材料。多环芳烃似乎是在宇宙大爆炸后不久形成的,在宇宙中广泛存在,并与新的恒星和系外行星有关。<br />
<br />
====Nucleobases====<br />
核酸碱基<br />
Observations suggest that the majority of organic compounds introduced on Earth by interstellar dust particles are considered principal agents in the formation of complex molecules, thanks to their peculiar [[catalysis|surface-catalytic]] activities.<ref name="Lincei">{{cite journal |last=Gallori |first=Enzo |title=Astrochemistry and the origin of genetic material |journal=Rendiconti Lincei |date=June 2011 |volume=22 |issue=2 |pages=113–118 |doi=10.1007/s12210-011-0118-4 |s2cid=96659714 }} "Paper presented at the Symposium 'Astrochemistry: molecules in space and time' (Rome, 4–5 November 2010), sponsored by Fondazione 'Guido Donegani', Accademia Nazionale dei Lincei."</ref><ref>{{cite journal |last=Martins |first=Zita |authorlink=Zita Martins |date=February 2011 |title=Organic Chemistry of Carbonaceous Meteorites |journal=[[Elements (journal)|Elements]] |volume=7 |issue=1 |pages=35–40 |doi=10.2113/gselements.7.1.35 }}</ref> Studies reported in 2008, based on <sup>12</sup>C/<sup>13</sup>C [[Natural abundance|isotopic ratios]] of organic compounds found in the Murchison meteorite, suggested that the RNA component uracil and related molecules, including [[xanthine]], were formed extraterrestrially.<ref name="Murch_base">{{cite journal |last1=Martins |first1=Zita |last2=Botta |first2=Oliver |last3=Fogel |first3=Marilyn L. |last4=Sephton |first4=Mark A. |last5=Glavin |first5=Daniel P. |last6=Watson |first6=Jonathan S. |last7=Dworkin |first7=Jason P. |last8=Schwartz |first8=Alan W. |last9=Ehrenfreund |first9=Pascale |display-authors=3 |date=15 June 2008 |title=Extraterrestrial nucleobases in the Murchison meteorite |journal=Earth and Planetary Science Letters |volume=270 |issue=1–2 |pages=130–136 |bibcode=2008E&PSL.270..130M |arxiv=0806.2286 |doi=10.1016/j.epsl.2008.03.026 |s2cid=14309508 }}</ref><ref>{{cite news |author=<!--Staff writer(s); no by-line.--> |date=14 June 2008 |title=We may all be space aliens: study |url=http://www.abc.net.au/news/2008-06-14/we-may-all-be-space-aliens-study/2471434 |location=Sydney |publisher=[[Australian Broadcasting Corporation]] |agency=[[Agence France-Presse]] |accessdate=2015-06-22 |url-status=live |archiveurl=https://web.archive.org/web/20150623073332/http://www.abc.net.au/news/2008-06-14/we-may-all-be-space-aliens-study/2471434 |archivedate=23 June 2015}}</ref> In 2011, a report based on [[NASA]] studies of meteorites found on Earth was published suggesting DNA components (adenine, guanine and related organic molecules) were made in outer space.<ref name="Lincei" /><ref name="Callahan">{{cite journal |last1=Callahan |first1=Michael P. |last2=Smith |first2=Karen E. |last3=Cleaves |first3=H. James, II |last4=Ruzica |first4=Josef |last5=Stern |first5=Jennifer C. |last6=Glavin |first6=Daniel P. |last7=House |first7=Christopher H. |last8=Dworkin |first8=Jason P. |display-authors=3 |date=23 August 2011 |title=Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=108 |issue=34 |pages=13995–13998 |bibcode=2011PNAS..10813995C |doi=10.1073/pnas.1106493108 |pmc=3161613 |pmid=21836052}}</ref><ref name="Steigerwald">{{cite web |url=http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html |title=NASA Researchers: DNA Building Blocks Can Be Made in Space |last=Steigerwald |first=John |date=8 August 2011 |work=[[Goddard Space Flight Center]] |publisher=NASA |location=Greenbelt, MD |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150623004556/http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html |archivedate=23 June 2015}}</ref> Scientists also found that the [[cosmic dust]] permeating the universe contains complex organics ("amorphous organic solids with a mixed [[Aromaticity|aromatic]]–[[Aliphatic compound|aliphatic]] structure") that could be created naturally, and rapidly, by stars.<ref name="Space-20111026">{{cite news |last= Chow |first= Denise |date= 26 October 2011 |title= Discovery: Cosmic Dust Contains Organic Matter from Stars |url= http://www.space.com/13401-cosmic-star-dust-complex-organic-compounds.html |website= Space.com |location= Ogden, UT |publisher= Purch |accessdate= 2015-06-23 |url-status= live |archiveurl= https://web.archive.org/web/20150714084901/http://www.space.com/13401-cosmic-star-dust-complex-organic-compounds.html |archivedate= 14 July 2015}}</ref><ref name="ScienceDaily-20111026">{{cite news |author=The University of Hong Kong |date=27 October 2011 |title=Astronomers discover complex organic matter exists throughout the universe |url=https://www.sciencedaily.com/releases/2011/10/111026143721.htm |location=Rockville, MD |publisher= ScienceDaily, LLC |url-status=live |archiveurl=https://web.archive.org/web/20150703185252/https://www.sciencedaily.com/releases/2011/10/111026143721.htm |archivedate=3 July 2015|author-link=University of Hong Kong }}</ref><ref name="Nature-20111026">{{cite journal |author1=Sun Kwok |authorlink1=Sun Kwok |author2=Yong Zhang |date=3 November 2011 |title=Mixed aromatic–aliphatic organic nanoparticles as carriers of unidentified infrared emission features |journal=Nature |volume=479 |issue=7371 |pages=80–83 |bibcode=2011Natur.479...80K |doi=10.1038/nature10542 |pmid=22031328|s2cid=4419859 }}</ref> [[Sun Kwok]] of [[University of Hong Kong|The University of Hong Kong]] suggested that these compounds may have been related to the development of life on Earth said that "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life."<ref name="Space-20111026" /><br />
<br />
观测结果表明,星际尘埃颗粒引入地球的大多数有机化合物被认为是形成复杂分子的主要媒介,这是因为它们具有特殊的表面催化活性。2008年报告的研究基于在默奇森陨石中发现的有机化合物的<sup>12</sup>C/<sup>13</sup>C同位素比率,表明RNA成分尿嘧啶和相关分子,包括黄嘌呤,是在外星形成的。 2011年,发表了一份基于美国宇航局对在地球上发现的陨石的研究的报告,表明DNA成分(腺嘌呤、鸟嘌呤和相关有机分子)是在外太空制造的。 科学家们还发现,弥漫在宇宙中的宇宙尘埃中含有复杂的有机物("具有芳香族-脂肪族混合结构的无定形有机固体"),这些有机物可能是由恒星自然地、迅速地创造出来的。香港大学的郭新 Sun Kwok提出,这些化合物可能与地球上生命的发展有关,他说:"如果是这样的话,地球上的生命可能更容易开始,因为这些有机物可以作为生命的基本原料。"<br />
<br />
====The sugar glycolaldehyde====<br />
<br />
糖-羟乙醛<br />
<br />
[[File:Formation of Glycolaldehyde in star dust.png|thumb|Formation of [[glycolaldehyde]] in [[Cosmic dust|stardust]]]]<br />
<br />
在星尘中羟乙醇醛的形成<br />
<br />
Glycolaldehyde, the first example of an interstellar sugar molecule, was detected in the star-forming region near the centre of our galaxy. It was discovered in 2000 by Jes Jørgensen and Jan Hollis.<ref name=Hollis>{{cite web |url=http://www.nasa.gov/vision/universe/starsgalaxies/interstellar_sugar.html |title=Space Sugar's a Sweet Find |first1=Lara |last1=Clemence |last2=Cohen |first2=Jarrett |date=7 February 2005 |work=Goddard Space Flight Center |publisher=NASA |location=Greenbelt, MD |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20160305002758/http://www.nasa.gov/vision/universe/starsgalaxies/interstellar_sugar.html |archivedate=5 March 2016}}</ref> In 2012, Jørgensen's team reported the detection of glycolaldehyde in a distant star system. The molecule was found around the [[protostar|protostellar]] binary [[IRAS 16293-2422]] 400 [[Light-year|light years]] from Earth.<ref name="NG-20120829">{{cite news |last=Than |first=Ker |date=30 August 2012 |title=Sugar Found in Space: A Sign of Life? |url=http://news.nationalgeographic.com/news/2012/08/120829-sugar-space-planets-science-life/ |work=National Geographic News |location=Washington, D.C. |publisher=[[National Geographic Society]] |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150714073830/http://news.nationalgeographic.com/news/2012/08/120829-sugar-space-planets-science-life/ |archivedate=14 July 2015}}</ref><ref name="AP-20120829">{{cite news |author=<!--Staff writer(s); no by-line.--> |date=29 August 2012 |title=Sweet! Astronomers spot sugar molecule near star |url=http://apnews.excite.com/article/20120829/DA0V31D80.html |work=[[Excite]] |location=Yonkers, NY |publisher=[[Mindspark Interactive Network]] |agency=[[Associated Press]] |accessdate=2015-06-23 |url-status=live |archiveurl=https://web.archive.org/web/20150714101929/http://apnews.excite.com/article/20120829/DA0V31D80.html |archivedate=14 July 2015}}</ref><ref>{{cite web |url=http://www.news.leiden.edu/news-2012/building-blocks-for-life-found-on-young-star.html |title=Building blocks of life found around young star |author=<!--Staff writer(s); no by-line.--> |date=30 September 2012 |website=News & Events |publisher=[[Leiden University]] |location=Leiden, the Netherlands |accessdate=2013-12-11 |url-status=live |archiveurl=https://web.archive.org/web/20131213135815/http://www.news.leiden.edu/news-2012/building-blocks-for-life-found-on-young-star.html |archivedate=13 December 2013}}</ref> Glycolaldehyde is needed to form RNA, which is similar in function to DNA. These findings suggest that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation.<ref>{{cite journal |last1=Jørgensen |first1=Jes K. |last2=Favre |first2=Cécile |last3=Bisschop |first3=Suzanne E. |last4=Bourke |first4=Tyler L. |last5=van Dishoeck |first5=Ewine F. |authorlink5=Ewine van Dishoeck |last6=Schmalzl |first6=Markus |display-authors=3 |date=2012 |title=Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA |url=http://www.eso.org/public/archives/releases/sciencepapers/eso1234/eso1234a.pdf |journal=The Astrophysical Journal Letters |volume=757 |issue=1 |arxiv=1208.5498 |bibcode=2012ApJ...757L...4J |doi=10.1088/2041-8205/757/1/L4 |accessdate=2015-06-23 |pages=L4 |s2cid=14205612 |url-status=live |archiveurl=https://web.archive.org/web/20150924021240/http://www.eso.org/public/archives/releases/sciencepapers/eso1234/eso1234a.pdf |archivedate=24 September 2015}}</ref><ref name="PNAS-20191113">{{Cite journal|last1=Furukawa|first1=Yoshihiro|last2=Chikaraishi|first2=Yoshito|last3=Ohkouchi|first3=Naohiko|last4=Ogawa|first4=Nanako O.|last5=Glavin|first5=Daniel P.|last6=Dworkin|first6=Jason P.|last7=Abe|first7=Chiaki|last8=Nakamura|first8=Tomoki|date=2019-11-13|title=Extraterrestrial ribose and other sugars in primitive meteorites|journal=Proceedings of the National Academy of Sciences|volume=116|issue=49|pages=24440–24445|language=en|doi=10.1073/pnas.1907169116|issn=0027-8424|pmid=31740594|pmc=6900709|bibcode=2019PNAS..11624440F}}</ref> Because sugars are associated with both metabolism and the [[genetic code]], two of the most basic aspects of life, it is thought the discovery of extraterrestrial sugar increases the likelihood that life may exist elsewhere in our galaxy.<ref name="Hollis" /><br />
<br />
羟乙醛是星际糖分子的第一个例子,在银河系中心附近的恒星形成区被发现。它是由詹斯·约根森 Jes Jørgensen和简·霍利斯 Jan Hollis在2000年发现的。2012年,Jørgensen的团队报告了在一个遥远的恒星系统中发现羟乙醛。该分子是在距离地球400光年的原恒星双星IRAS 16293-2422周围发现的。羟乙醛是形成RNA所需要的,RNA的功能与DNA相似。这些发现表明,复杂的有机分子可能在行星形成之前就在恒星系统中形成,最终在行星形成的早期到达年轻行星上。由于糖类与新陈代谢和遗传密码这两个生命最基本的方面有关,因此认为发现地外糖类增加了银河系其他地方可能存在生命的可能性。<br />
<br />
==== Polyphosphates ====<br />
多聚磷酸盐<br />
A problem in most scenarios of abiogenesis is that the thermodynamic equilibrium of amino acid versus peptides is in the direction of separate amino acids. What has been missing is some force that drives polymerization. The resolution of this problem may well be in the properties of [[polyphosphate]]s.<ref>{{cite journal |last1=Brown |first1=Michael R. W. |last2=Kornberg |first2=Arthur |authorlink2=Arthur Kornberg |date=16 November 2004 |title=Inorganic polyphosphate in the origin and survival of species |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=101 |issue=46 |pages=16085–16087 |bibcode=2004PNAS..10116085B |doi=10.1073/pnas.0406909101|pmc=528972 |pmid=15520374}}</ref><ref>{{cite web |url=http://www.science.siu.edu/microbiology/micr425/425Notes/14-OriginLife.html |title=The Origin of Life |last=Clark |first=David P. |date=3 August 1999 |website=Microbiology 425: Biochemistry and Physiology of Microorganism |publisher=College of Science; [[Southern Illinois University Carbondale]] |location=Carbondale, IL |type=Lecture |archiveurl=https://web.archive.org/web/20001002142750/http://www.science.siu.edu/microbiology/micr425/425Notes/14-OriginLife.html |archivedate=2000-10-02 |url-status=dead |accessdate=2015-06-26}}</ref> Polyphosphates are formed by polymerization of ordinary monophosphate ions PO<sub>4</sub><sup>3-</sup>. Several mechanisms of organic molecule synthesis have been investigated. Polyphosphates cause polymerization of amino acids into peptides. They are also logical precursors in the synthesis of such key biochemical compounds as [[adenosine triphosphate]] (ATP). A key issue seems to be that calcium reacts with soluble phosphate to form insoluble [[calcium phosphate]] ([[apatite]]), so some plausible mechanism must be found to keep calcium ions from causing precipitation of phosphate. There has been much work on this topic over the years, but an interesting new idea is that meteorites may have introduced reactive phosphorus species on the early Earth.<ref>{{cite journal |last=Pasek |first=Matthew A. |date=22 January 2008 |title=Rethinking early Earth phosphorus geochemistry |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=105 |issue=3 |pages=853–858 |bibcode=2008PNAS..105..853P |doi=10.1073/pnas.0708205105 |pmc=2242691 |pmid=18195373}}</ref><br />
<br />
Based on recent [[computer simulation|computer model studies]], the [[organic compound|complex organic molecules]] necessary for life may have formed in the [[protoplanetary disk]] of [[cosmic dust|dust grains]] surrounding the [[Sun]] before the formation of the Earth.<ref name="Space-20120329">{{cite news |last=Moskowitz |first=Clara |date=29 March 2012 |title=Life's Building Blocks May Have Formed in Dust Around Young Sun |url=http://www.space.com/15089-life-building-blocks-young-sun-dust.html |website=[[Space.com]] |location=Salt Lake City, UT |publisher=[[Purch]] |accessdate=2012-03-30 |url-status=live |archiveurl=https://web.archive.org/web/20120814205056/http://www.space.com/15089-life-building-blocks-young-sun-dust.html |archivedate=14 August 2012}}</ref><ref>{{cite journal|last1=Ciesla|first1=F.J.|last2=Sandford|first2=S.A.|title=Organic Synthesis via Irradiation and Warming of Ice Grains in the Solar Nebula|journal=Science|date=29 March 2012|volume=336|issue=6080|pages=452–454|doi=10.1126/science.1217291|pmid=22461502|bibcode=2012Sci...336..452C|hdl=2060/20120011864|s2cid=25454671|hdl-access=free}}</ref> According to the computer studies, this same process may also occur around other [[star]]s that acquire [[planet]]s. (Also see [[#Extraterrestrial organic molecules|Extraterrestrial organic molecules]]).<br />
<br />
在大多数非生物发生的情况下,一个问题是氨基酸与肽的热力学平衡是向着分离氨基酸的方向发展的。一直以来,缺少的是某种推动聚合的力量。这个问题的解决很可能在于多聚磷酸盐的特性。聚磷酸盐是由普通的单磷酸离子PO<sub>4</sub><sup>3-</sup>聚合而成。目前已经研究了几种有机分子合成的机制。多聚磷酸盐能使氨基酸聚合成肽。它们也是合成三磷酸腺苷(ATP)等关键生化化合物的逻辑前体。一个关键的问题似乎是,钙与可溶性磷酸盐反应形成不溶性的磷酸钙(磷灰石),所以必须找到一些似合理的机制来防止钙离子引起磷酸盐的沉淀。多年来,关于这个主题的工作很多,但一个有趣的新想法是,陨石可能在早期地球上引入了活性磷物种。根据最近的计算机模型研究,在地球形成之前,生命所必需的复杂有机分子可能已经在太阳周围的尘粒的原行星盘中形成了。根据计算机研究,这个相同的过程也可能发生在其他获得行星的恒星周围。<br />
<br />
The accumulation and concentration of organic molecules on a planetary surface is also considered an essential early step for the origin of life.<ref name="NASA strategy 2015"/> Identifying and understanding the mechanisms that led to the production of prebiotic molecules in various environments is critical for establishing the inventory of ingredients from which life originated on Earth, assuming that the abiotic production of molecules ultimately influenced the selection of molecules from which life emerged.<ref name="NASA strategy 2015"/><br />
<br />
有机分子在行星表面的积累和集中也被认为是生命起源的一个重要的早期步骤。假设分子的非生物生产最终影响了生命涌现的分子选择,那么识别和理解导致在各种环境中产生前生物分子的机制对于建立地球上生命起源的成分清单至关重要。<br />
<br />
In 2019, scientists reported detecting, for the first time, [[Sugar|sugar molecules]], including [[ribose]], in [[meteorite]]s, suggesting that chemical processes on [[asteroid]]s can produce some fundamentally essential bio-ingredients important to [[life]], and supporting the notion of an [[RNA world]] prior to a DNA-based origin of life on Earth, and possibly, as well, the notion of [[panspermia]].<ref name="NASA-20191118">{{cite news |last1=Steigerwald |first1=Bill |last2=Jones |first2=Nancy |last3=Furukawa |first3=Yoshihiro |title=First Detection of Sugars in Meteorites Gives Clues to Origin of Life |url=https://www.nasa.gov/press-release/goddard/2019/sugars-in-meteorites |date=18 November 2019 |work=[[NASA]] |accessdate=18 November 2019 }}</ref><ref name="PNAS-20191113" /><br />
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2019年,科学家报告首次在陨石中检测到包括核糖在内的糖分子,表明小行星上的化学过程可以产生一些对生命很重要的基本生物原料,并支持地球上以DNA为基础的生命起源之前的RNA世界的概念,也可能支持泛种论的概念。<br />
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=== Chemical synthesis in the laboratory===<br />
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实验室中的化学合成 <br />
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As early as the 1860s, experiments have demonstrated that biologically relevant molecules can be produced from interaction of simple carbon sources with abundant inorganic catalysts.<br />
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早在19世纪60年代,就有实验证明,简单的碳源与丰富的无机催化剂相互作用可以产生生物相关的分子。<br />
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====Fox proteinoids====<br />
<br />
福克斯类蛋白<br />
{{Main|Proteinoid}}<br />
<br />
In trying to uncover the intermediate stages of abiogenesis mentioned by Bernal, [[Sidney W. Fox|Sidney Fox]] in the 1950s and 1960s studied the spontaneous formation of [[peptide]] structures (small chains of amino acids) under conditions that might plausibly have existed early in Earth's history. In one of his experiments, he allowed amino acids to dry out as if puddled in a warm, dry spot in prebiotic conditions: In an experiment to set suitable conditions for life to form, Fox collected volcanic material from a [[cinder cone]] in [[Hawaii]]. He discovered that the temperature was over 100 C just {{convert|4|in}} beneath the surface of the cinder cone, and suggested that this might have been the environment in which life was created—molecules could have formed and then been washed through the loose volcanic ash into the sea. He placed lumps of lava over amino acids derived from methane, ammonia and water, sterilized all materials, and baked the lava over the amino acids for a few hours in a glass oven. A brown, sticky substance formed over the surface, and when the lava was drenched in sterilized water, a thick, brown liquid leached out. He found that, as they dried, the amino acids formed long, often cross-linked, thread-like, submicroscopic [[Peptide|polypeptide]] molecules.<ref name="foxexp"/><br />
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在试图发现Bernal提到的非生物发生的中间阶段时,西德尼·福克斯Sidney Fox在20世纪50年代和60年代研究了在地球历史早期可能存在的条件下自发形成的肽结构(小的氨基酸链)。在他的一个实验中,他让氨基酸在前生物条件下,像在温暖干燥的地方搅拌一样变干燥。在一个为生命的形成设置合适条件的实验中,Fox从夏威夷的一个火山灰烬锥状物中收集了火山材料。他发现火山灰烬锥状物表面下4英寸(100毫米)的温度就超过了100 C,并认为这可能是生命诞生的环境--分子可能已经形成,然后通过松散的火山灰被冲入海中。他将一块块的熔岩放在由甲烷、氨和水产生的氨基酸上,对所有材料进行灭菌,并将熔岩放在氨基酸上,在玻璃炉中烘烤几个小时。在表面形成了一种棕色的粘性物质,当把熔岩浸泡在消毒水中时,就会有浓稠的棕色液体渗出。他发现,随着它们的干燥,氨基酸形成了长长的、常常是交联的、线状的、亚显微的多肽分子。<br />
<br />
====Sugars====<br />
糖类<br />
In particular, experiments by [[Alexander Butlerov|Butlerov]] (the [[formose reaction]]) showed that tetroses, pentoses, and hexoses are produced when formaldehyde is heated under basic conditions with divalent metal ions like calcium. The reaction was scrutinized and subsequently proposed to be autocatalytic by Breslow in 1959.<br />
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特别是布列特洛夫Butlerov的实验(甲醛聚糖反应)表明,当甲醛在碱性条件下与钙等二价金属离子加热时,会产生四糖、五糖和六糖。1959年,布雷斯洛 Breslow对该反应进行了仔细研究,随后提出该反应是自催化反应。<br />
<br />
====Nucleobases====<br />
核酸碱基<br />
Similar experiments (see below) demonstrate that nucleobases like guanine and adenine could be synthesized from simple carbon and nitrogen sources like hydrogen cyanide and ammonia.<br />
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类似的实验(见下文)表明,像鸟嘌呤和腺嘌呤这样的核酸碱基可以从简单的碳和氮源如氰化氢和氨合成。<br />
***讨论:我觉得一方面我们要探寻生命起源前化学反应产生生命所需基本原料的可能,另一方面我们还需要知道这些反应发生的几率和量***<br />
[[Formamide]] produces all four ribonucleotides and other biological molecules when warmed in the presence of various terrestrial minerals. Formamide is ubiquitous in the Universe, produced by the reaction of water and [[hydrogen cyanide]] (HCN). It has several advantages as a biotic precursor, including the ability to easily become concentrated through the evaporation of water.<ref name="Saladino2012">{{cite journal |last1=Saladino |first1=Raffaele |last2=Crestini |first2=Claudia |last3=Pino |first3=Samanta |last4=Costanzo |first4=Giovanna |last5=Di Mauro |first5=Ernesto |display-authors=3 |date=March 2012 |title=Formamide and the origin of life. |journal=[[Physics of Life Reviews]] |volume=9 |issue=1 |pages=84–104 |bibcode=2012PhLRv...9...84S |doi=10.1016/j.plrev.2011.12.002 |pmid=22196896|hdl=2108/85168 |url=https://art.torvergata.it/bitstream/2108/85168/1/PoLRev%202012.pdf }}</ref><ref name="Saladino2012b">{{cite journal |last1=Saladino |first1=Raffaele |last2=Botta |first2=Giorgia |last3=Pino |first3=Samanta |last4=Costanzo |first4=Giovanna |last5=Di Mauro |first5=Ernesto |display-authors=3 |date=July 2012 |title=From the one-carbon amide formamide to RNA all the steps are prebiotically possible |journal=[[Biochimie]] |volume=94 |issue=7 |pages=1451–1456 |doi=10.1016/j.biochi.2012.02.018 |pmid=22738728}}</ref> Although HCN is poisonous, it only affects [[aerobic organism]]s ([[eukaryote]]s and aerobic bacteria), which did not yet exist. It can play roles in other chemical processes as well, such as the synthesis of the amino acid [[glycine]].<ref name="Follmann2009" /><br />
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甲酰胺在各种陆地矿物质存在下升温时,可产生所有四种核糖核苷酸和其他生物分子。甲酰胺在宇宙中无处不在,由水和氰化氢(HCN)反应生成。作为一种生物的前体,它有几个优点,包括通过水的蒸发而容易浓缩的能力。虽然HCN是有毒的,但它只影响需氧生物(真核生物和需氧细菌),它们当时还不存在。它也可以在其他化学过程中发挥作用,比如氨基酸甘氨酸的合成。<br />
<br />
In March 2015, NASA scientists reported that, for the first time, complex DNA and RNA organic compounds of life, including uracil, cytosine and [[thymine]], have been formed in the laboratory under outer space conditions, using starting chemicals, such as pyrimidine, found in meteorites. Pyrimidine, like PAHs, the most carbon-rich chemical found in the Universe, may have been formed in [[red giant]] stars or in interstellar dust and gas clouds.<ref name="NASA-20150303">{{cite web |url=http://www.nasa.gov/content/nasa-ames-reproduces-the-building-blocks-of-life-in-laboratory |title=NASA Ames Reproduces the Building Blocks of Life in Laboratory |editor-last=Marlaire |editor-first=Ruth |date=3 March 2015 |work=Ames Research Center |publisher=NASA |location=Moffett Field, CA |accessdate=2015-03-05 |url-status=live |archiveurl=https://web.archive.org/web/20150305083306/http://www.nasa.gov/content/nasa-ames-reproduces-the-building-blocks-of-life-in-laboratory/ |archivedate=5 March 2015}}</ref> A group of Czech scientists reported that all four RNA-bases may be synthesized from formamide in the course of high-energy density events like extraterrestrial impacts.<ref>{{cite journal | last1 = Ferus | first1 = Martin | last2 = Nesvorný | first2 = David | last3 = Šponer | first3 = Jiří | last4 = Kubelík | first4 = Petr | last5 = Michalčíková | first5 = Regina | last6 = Shestivská | first6 = Violetta | last7 = Šponer | first7 = Judit E. | last8 = Civiš | first8 = Svatopluk | year = 2015 | title = High-energy chemistry of formamide: A unified mechanism of nucleobase formation | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 112 | issue = 3| pages = 657–662 | doi = 10.1073/pnas.1412072111 | pmid = 25489115 | bibcode = 2015PNAS..112..657F | pmc = 4311869 }}</ref><br />
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2015年3月,美国宇航局科学家报告称,在外太空条件下,利用陨石中发现的嘧啶等起始化学物质,首次在实验室中形成了生命的复杂DNA和RNA有机化合物,包括尿嘧啶、胞嘧啶和胸腺嘧啶。嘧啶和多环芳烃一样,是宇宙中发现的最富含碳的化学物质,可能是在红巨星中或星际尘埃和气体云中形成的。一组捷克科学家报告说,所有四种RNA碱基可能是在如地外撞击等高能密度事件过程中由甲酰胺合成的。<br />
<br />
====Use of high temperature====<br />
使用高温<br />
In 1961, it was shown that the nucleic acid [[purine]] base [[adenine]] can be formed by heating aqueous [[ammonium cyanide]] solutions.<ref>{{cite journal |last=Oró |first=Joan |authorlink=Joan Oró |date=16 September 1961 |title=Mechanism of Synthesis of Adenine from Hydrogen Cyanide under Possible Primitive Earth Conditions |journal=Nature |volume=191 |issue=4794 |pages=1193–1194 |bibcode=1961Natur.191.1193O |doi=10.1038/1911193a0 |pmid=13731264|s2cid=4276712 }}</ref><br />
<br />
1961年,研究表明核酸嘌呤碱基腺嘌呤可以通过加热氰化铵水溶液形成。<br />
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====Use of low (freezing) temperature====<br />
使用低(极冷的)温<br />
Other pathways for synthesizing bases from inorganic materials were also reported.<ref name="Basile1984">{{cite journal |last1=Basile |first1=Brenda |last2=Lazcano |first2=Antonio |authorlink2=Antonio Lazcano |last3=Oró |first3=Joan |year=1984 |title=Prebiotic syntheses of purines and pyrimidines |journal=[[Advances in Space Research]] |volume=4 |issue=12 |pages=125–131 |bibcode=1984AdSpR...4..125B |doi=10.1016/0273-1177(84)90554-4 |pmid=11537766}}</ref> Orgel and colleagues have shown that freezing temperatures are advantageous for the synthesis of purines, due to the concentrating effect for key precursors such as hydrogen cyanide.<ref>{{cite journal |last=Orgel |first=Leslie E. |date=August 2004 |title=Prebiotic Adenine Revisited: Eutectics and Photochemistry |journal=Origins of Life and Evolution of Biospheres |volume=34 |issue=4 |pages=361–369 |bibcode=2004OLEB...34..361O |doi=10.1023/B:ORIG.0000029882.52156.c2 |pmid=15279171|s2cid=4998122 }}</ref> Research by Miller and colleagues suggested that while adenine and [[guanine]] require freezing conditions for synthesis, [[cytosine]] and [[uracil]] may require boiling temperatures.<ref>{{cite journal |last1=Robertson |first1=Michael P. |last2=Miller |first2=Stanley L. |date=29 June 1995 |title=An efficient prebiotic synthesis of cytosine and uracil |journal=Nature |volume=375 |issue=6534 |pages=772–774 |bibcode=1995Natur.375..772R |doi=10.1038/375772a0 |pmid=7596408|s2cid=4351012 }}</ref> Research by the Miller group notes the formation of seven different amino acids and 11 types of [[nucleobase]]s in ice when ammonia and [[cyanide]] were left in a freezer from 1972 to 1997.<ref>{{cite journal |last=Fox |first=Douglas |date=February 2008 |url=http://discovermagazine.com/2008/feb/did-life-evolve-in-ice |title=Did Life Evolve in Ice? |journal=[[Discover (magazine)|Discover]] |accessdate=2008-07-03 |url-status=live |archiveurl=https://web.archive.org/web/20080630043228/http://discovermagazine.com/2008/feb/did-life-evolve-in-ice |archivedate=30 June 2008}}</ref><ref>{{cite journal |last1=Levy |first1=Matthew |last2=Miller |first2=Stanley L. |last3=Brinton |first3=Karen |last4=Bada |first4=Jeffrey L. |authorlink4=Jeffrey L. Bada |date=June 2000 |title=Prebiotic Synthesis of Adenine and Amino Acids Under Europa-like Conditions |journal=[[Icarus (journal)|Icarus]] |volume=145 |issue=2 |pages=609–613 |bibcode=2000Icar..145..609L |doi=10.1006/icar.2000.6365 |pmid=11543508}}</ref> Other work demonstrated the formation of s-[[triazine]]s (alternative nucleobases), [[pyrimidine]]s (including cytosine and uracil), and adenine from urea solutions subjected to freeze-thaw cycles under a reductive atmosphere (with spark discharges as an energy source).<ref>{{cite journal |last1=Menor-Salván |first1=César |last2=Ruiz-Bermejo |first2=Marta |last3=Guzmán |first3=Marcelo I. |last4=Osuna-Esteban |first4=Susana |last5=Veintemillas-Verdaguer |first5=Sabino |date=20 April 2009 |title=Synthesis of Pyrimidines and Triazines in Ice: Implications for the Prebiotic Chemistry of Nucleobases |journal=[[Chemistry: A European Journal]] |volume=15 |issue=17 |pages=4411–4418 |doi=10.1002/chem.200802656 |pmid=19288488}}</ref> The explanation given for the unusual speed of these reactions at such a low temperature is [[Eutectic system|eutectic freezing]]. As an ice crystal forms, it stays pure: only molecules of water join the growing crystal, while impurities like salt or cyanide are excluded. These impurities become crowded in microscopic pockets of liquid within the ice, and this crowding causes the molecules to collide more often. Mechanistic exploration using quantum chemical methods provide a more detailed understanding of some of the chemical processes involved in chemical evolution, and a partial answer to the fundamental question of molecular biogenesis.<ref>{{cite journal |last1=Roy |first1=Debjani |last2=Najafian |first2=Katayoun |last3=von Ragué Schleyer |first3=Paul |authorlink3=Paul von Ragué Schleyer |date=30 October 2007 |title=Chemical evolution: The mechanism of the formation of adenine under prebiotic conditions |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=104 |issue=44 |pages=17272–17277 |bibcode=2007PNAS..10417272R |doi=10.1073/pnas.0708434104|pmc=2077245 |pmid=17951429}}</ref><br />
<br />
还有人报道了从无机材料合成碱基的其他途径。奥格尔Orgel及其同事的研究表明,由于氰化氢等关键前体的浓缩作用,冷冻温度对嘌呤的合成是有利的。Miller及其同事的研究表明,腺嘌呤和鸟嘌呤的合成需要冷冻条件,而胞嘧啶和尿嘧啶可能需要沸腾的温度。Miller课题组的研究指出,从1972年到1997年,当氨和氰化物被放置在冰柜中时,在冰中形成了7种不同的氨基酸和11种核酸碱基。其他研究证明了s-三嗪(替代核酸碱基)、嘧啶(包括胞嘧啶和尿嘧啶)和腺嘌呤从尿素溶液在还原性气氛下(以火花放电为能量来源)经过冻融循环形成。对于这些反应在如此低的温度下的异常速度,给出的解释是共晶凝固。当冰晶形成时,它保持纯净:只有水分子加入生长的晶体,而盐或氰化物等杂质被排除在外。这些杂质在冰内变得拥挤在微观的液体口袋中,这种拥挤导致分子更频繁地碰撞。利用量子化学方法进行机理探索,可以更详细地了解化学演化中的一些化学过程,并对分子生物发生的基本问题做出部分回答。<br />
<br />
====Use of less-reducing gas in Miller–Urey experiment====<br />
<br />
在Miller-Urey实验中使用还原性较低的气体<br />
<br />
At the time of the Miller–Urey experiment, scientific consensus was that the early Earth had a reducing atmosphere with compounds relatively rich in hydrogen and poor in oxygen (e.g., CH<sub>4</sub> and NH<sub>3</sub> as opposed to CO<sub>2</sub> and [[nitrogen dioxide]] (NO<sub>2</sub>)). However, current scientific consensus describes the primitive atmosphere as either weakly reducing or neutral<ref name="Cleaves 2008">{{cite journal |last1=Cleaves |first1=H. James |last2=Chalmers |first2=John H. |last3=Lazcano |first3=Antonio |last4=Miller |first4=Stanley L. |last5=Bada |first5=Jeffrey L. |display-authors=3 |date=April 2008 |title=A Reassessment of Prebiotic Organic Synthesis in Neutral Planetary Atmospheres |journal=Origins of Life and Evolution of Biospheres |volume=38 |issue=2 |pages=105–115 |bibcode=2008OLEB...38..105C |doi=10.1007/s11084-007-9120-3|pmid=18204914|s2cid=7731172 }}</ref><ref name="Chyba 2005">{{cite journal |last=Chyba |first=Christopher F. |s2cid=93303848 |date=13 May 2005 |title=Rethinking Earth's Early Atmosphere |journal=Science |volume=308 |issue=5724 |pages=962–963 |doi=10.1126/science.1113157 |pmid=15890865}}</ref> (see also [[Great Oxygenation Event|Oxygen Catastrophe]]). Such an atmosphere would diminish both the amount and variety of amino acids that could be produced, although studies that include [[iron]] and [[carbonate]] minerals (thought present in early oceans) in the experimental conditions have again produced a diverse array of amino acids.<ref name="Cleaves 2008" /> Other scientific research has focused on two other potential reducing environments: [[outer space]] and deep-sea thermal vents.<ref>{{harvnb|Barton|Briggs|Eisen|Goldstein|2007|pp=93–95}}</ref><ref>{{harvnb|Bada|Lazcano|2009|pp=56–57}}</ref><ref name="Bada 2003">{{cite journal |last1=Bada |first1=Jeffrey L. |last2=Lazcano |first2=Antonio |date=2 May 2003 |url=http://astrobiology.berkeley.edu/PDFs_articles/Bada_Science2003.pdf |title=Prebiotic Soup – Revisiting the Miller Experiment |journal=Science |volume=300 |issue=5620 |pages=745–746 |doi=10.1126/science.1085145 |pmid=12730584 |s2cid=93020326 |accessdate=2015-06-13 |url-status=live |archiveurl=https://web.archive.org/web/20160304222002/http://astrobiology.berkeley.edu/PDFs_articles/Bada_Science2003.pdf |archivedate=4 March 2016}}</ref><br />
<br />
在Miller-Urey实验时,科学界的共识是,早期地球有一个还原性大气层,其化合物中氢气相对丰富,而氧气相对贫乏(如CH<sub>4</sub>和NH<sub>3</sub>,而不是CO<sub>2</sub> 和二氧化氮(NO<sub>2</sub>))。然而,目前的科学共识将原始大气层描述为弱还原性或中性(另见氧气灾难)。这样的大气会减少可以产生的氨基酸的数量和种类,尽管在实验条件中加入铁和碳酸盐矿物(被认为存在于早期海洋中)的研究又产生了多种氨基酸。其他科学研究集中在另外两种潜在的还原性环境:外太空和深海热喷口。<br />
<br />
====Synthesis based on hydrogen cyanide====<br />
<br />
基于氰化氢的合成 <br />
<br />
A research project completed in 2015 by [[John Sutherland (chemist)|John Sutherland]] and others found that a network of reactions beginning with hydrogen cyanide and hydrogen sulfide, in streams of water irradiated by UV light, could produce the chemical components of proteins and lipids, as well as those of RNA,<ref>{{cite news |last=Service |first=Robert F. |date=16 March 2015 |title=Researchers may have solved origin-of-life conundrum |url=http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |work=Science |type=News |location=Washington, D.C. |publisher=American Association for the Advancement of Science |accessdate=2015-07-26 |url-status=live |archiveurl=https://web.archive.org/web/20150812103559/http://news.sciencemag.org/biology/2015/03/researchers-may-have-solved-origin-life-conundrum |archivedate=12 August 2015}}</ref><ref name="patel">{{cite journal |last1=Patel |first1=Bhavesh H.|last2=Percivalle |first2=Claudia |last3=Ritson |first3=Dougal J. |last4=Duffy |first4=Colm D. |last5=Sutherland |first5=John D. |authorlink5=John Sutherland (chemist) |date=April 2015 |title=Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism |journal=[[Nature Chemistry]] |volume=7 |issue=4 |pages=301–307 |bibcode=2015NatCh...7..301P |doi=10.1038/nchem.2202 |pmid=25803468 |ref=harv |pmc=4568310}}</ref> while not producing a wide range of other compounds.<ref>{{harvnb|Patel|Percivalle|Ritson|Duffy|2015|p=302}}</ref> The researchers used the term "cyanosulfidic" to describe this network of reactions.<ref name="patel" /><br />
<br />
约翰·萨瑟兰John Sutherland 等人在2015年完成的一个研究项目发现,在紫外线照射的水流中,一个以氰化氢和硫化氢为起点的反应网络,可以产生蛋白质和脂类的化学成分,以及RNA的化学成分,同时不产生其他多种化合物。研究人员用 "氰基硫化物 "一词来描述这个反应网络。<br />
<br />
====Issues during laboratory synthesis====<br />
<br />
实验室合成过程中的问题 <br />
<br />
The spontaneous formation of complex polymers from abiotically generated monomers under the conditions posited by the "soup" theory is not at all a straightforward process. Besides the necessary basic organic monomers, compounds that would have prohibited the formation of polymers were also formed in high concentration during the Miller–Urey and [[Joan Oró]] experiments.<ref>{{cite journal |last1=Oró |first1=Joan |last2=Kimball |first2=Aubrey P. |date=February 1962 |title=Synthesis of purines under possible primitive earth conditions: II. Purine intermediates from hydrogen cyanide |journal=[[Archives of Biochemistry and Biophysics]] |volume=96 |issue=2 |pages=293–313 |doi=10.1016/0003-9861(62)90412-5 |pmid=14482339}}</ref> The Miller–Urey experiment, for example, produces many substances that would react with the amino acids or terminate their coupling into peptide chains.<ref>{{cite book |editor-last=Ahuja |editor-first=Mukesh |year=2006 |chapter=Origin of Life |chapterurl=https://books.google.com/books?id=VJF12TlT58kC&pg=PA11 |title=Life Science |volume=1 |location=Delhi |publisher=Isha Books |page=11 |isbn=978-81-8205-386-1 |oclc=297208106 |ref=harv}}{{Unreliable source?|reason=What material is Ahuja editing? Further, see use of Ahuja material in the Iron-sulfur world section in this WP article, among others. See also: Wikipedia talk:Noticeboard for India-related topics/Archive 42#Problem with ISHA books as references|date=June 2015}}</ref><br />
<br />
在"汤"理论提出的条件下,由非生物生成的单体自发形成复杂的聚合物,根本不是一个简单的过程。除了必要的基本有机单体外,在Miller-Urey和琼·奥罗 Joan Oró实验过程中,还形成了高浓度的禁止聚合物形成的化合物。例如,Miller-Urey实验会产生许多与氨基酸反应或终止其偶联成肽链的物质。<br />
=== Autocatalysis ===<br />
<br />
自催化 <br />
<br />
{{Main|Autocatalysis}}<br />
<br />
[[Autocatalysis|Autocatalysts]] are substances that catalyze the production of themselves and therefore are "molecular replicators." The simplest self-replicating chemical systems are autocatalytic, and typically contain three components: a product molecule and two precursor molecules. The product molecule joins together the precursor molecules, which in turn produce more product molecules from more precursor molecules. The product molecule catalyzes the reaction by providing a complementary template that binds to the precursors, thus bringing them together. Such systems have been demonstrated both in biological [[macromolecule]]s and in small organic molecules.<ref name="Paul2004">{{cite journal |last1=Paul |first1=Natasha |last2=Joyce |first2=Gerald F. |date=December 2004 |title=Minimal self-replicating systems |journal=Current Opinion in Chemical Biology |volume=8 |issue=6 |pages=634–639 |doi=10.1016/j.cbpa.2004.09.005|pmid=15556408}}</ref><ref name="Bissette2013">{{cite journal |last1=Bissette |first1=Andrew J. |last2=Fletcher |first2=Stephen P. |date=2 December 2013 |title=Mechanisms of Autocatalysis |journal=Angewandte Chemie International Edition |volume=52 |issue=49 |pages=12800–12826 |doi=10.1002/anie.201303822 |pmid=24127341}}</ref> Systems that do not proceed by template mechanisms, such as the self-reproduction of [[micelle]]s and [[Vesicle (biology and chemistry)|vesicles]], have also been observed.<ref name="Bissette2013" /><br />
<br />
自催化剂是指能催化生产自身的物质,因此是 "分子复制器"。最简单的自我复制化学体系是自催化的,通常包含三个组成部分:一个产物分子和两个前体分子。产物分子将前体分子们连接在一起,反过来由更多的前体分子产生更多的产物分子。产物分子通过提供一个互补的模板来催化反应,该模板与前体结合,从而使它们结合在一起。这样的系统在生物大分子和有机小分子中都得到了证明。也观察到了不通过模板机制进行的系统,如胶束和囊泡的自我再生。<br />
<br />
It has been proposed that life initially arose as autocatalytic chemical networks.<ref>{{harvnb|Kauffman|1993|loc=chpt. 7}}</ref> British [[ethologist]] [[Richard Dawkins]] wrote about autocatalysis as a potential explanation for the origin of life in his 2004 book ''[[The Ancestor's Tale]]''.<ref>{{harvnb|Dawkins|2004}}</ref> In his book, Dawkins cites experiments performed by [[Julius Rebek]] and his colleagues in which they combined amino adenosine and [[pentafluorophenyl esters]] with the autocatalyst amino adenosine triacid ester (AATE). One product was a variant of AATE, which catalyzed the synthesis of themselves. This experiment demonstrated the possibility that autocatalysts could exhibit competition within a population of entities with heredity, which could be interpreted as a rudimentary form of natural selection.<ref>{{cite journal |last1=Tjivikua |first1=T. |last2=Ballester |first2=Pablo |last3=Rebek |first3=Julius Jr. |authorlink3=Julius Rebek |date=January 1990 |title=Self-replicating system |journal=[[Journal of the American Chemical Society]] |volume=112 |issue=3 |pages=1249–1250 |doi=10.1021/ja00159a057 }}</ref><ref>{{cite news |last=Browne |first=Malcolm W. |authorlink=Malcolm Browne |date=30 October 1990 |title=Chemists Make Molecule With Hint of Life |url=https://www.nytimes.com/1990/10/30/science/chemists-make-molecule-with-hint-of-life.html |newspaper=The New York Times |location=New York |accessdate=2015-07-14 |url-status=live |archiveurl=https://web.archive.org/web/20150721135740/http://www.nytimes.com/1990/10/30/science/chemists-make-molecule-with-hint-of-life.html |archivedate=21 July 2015}}</ref><br />
<br />
有人提出,生命最初是以自催化的化学网络产生的。英国伦理学家理查德·道金斯 Richard Dawkins在2004年出版的《祖先的故事》(The Ancestor's Tale)一书中写道,自催化是生命起源的一种可能的解释。在书中,Dawkins引用了朱利叶斯·雷贝克 Julius Rebek和他的同事所做的实验,他们将氨基腺苷和五氟苯基酯与自催化剂氨基腺苷三酸酯(AATE)相结合。其中一种产物是AATE的变体,它能催化自身的合成。这一实验表明,自催化剂有可能在具有遗传性的实体种群中表现出竞争,这可以被解释为自然选择的一种基本形式。<br />
<br />
== Encapsulation: morphology ==<br />
胶囊化:形态学<br />
{{see also|Evolution of cells}}<br />
<br />
=== Encapsulation without a membrane ===<br />
无膜胶囊化<br />
====Oparin's coacervate====<br />
Oparin的(细胞)团聚体<br />
====Membraneless polyester droplets====<br />
<br />
无膜聚酯液滴 <br />
<br />
Researchers Tony Jia and Kuhan Chandru<ref>{{cite journal |last1=Jia |first1=Tony Z. |last2=Chandru |first2=Kuhan |last3=Hongo |first3=Yayoi |last4=Afrin |first4=Rehana |last5=Usui |first5=Tomohiro |last6=Myojo |first6=Kunihiro |last7=Cleaves |first7=H. James |title=Membraneless polyester microdroplets as primordial compartments at the origins of life |journal=Proceedings of the National Academy of Sciences |volume=116 |issue=32 |date=22 July 2019 |pages=15830–15835 |doi=10.1073/pnas.1902336116|pmid=31332006 |pmc=6690027 }}</ref> have proposed that membraneless polyesters droplets could have been significant in the Origins of Life.<ref>{{Cite journal|last1=Chandru|first1=Kuhan|last2=Mamajanov|first2=Irena|last3=Cleaves|first3=H. James|last4=Jia|first4=Tony Z.|date=January 2020|title=Polyesters as a Model System for Building Primitive Biologies from Non-Biological Prebiotic Chemistry|journal=Life|language=en|volume=10|issue=1|pages=6|doi=10.3390/life10010006|pmc=7175156|pmid=31963928}}</ref> Given the "messy" nature of prebiotic chemistry,<ref>{{cite web |last1=Marc |first1=Kaufman |title=NASA Astrobiology |url=https://astrobiology.nasa.gov/news/messy-chemistry-a-new-way-to-approach-the-origins-of-life/|date = 18 July 2019 |website=astrobiology.nasa.gov |language=en-EN}}</ref><ref>{{cite journal |last1=Guttenberg |first1=Nicholas |last2=Virgo |first2=Nathaniel |last3=Chandru |first3=Kuhan |last4=Scharf |first4=Caleb |last5=Mamajanov |first5=Irena |title=Bulk measurements of messy chemistries are needed for a theory of the origins of life |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |date=13 November 2017 |volume=375 |issue=2109 |pages=20160347 |doi=10.1098/rsta.2016.0347|pmid=29133446 |pmc=5686404 |bibcode=2017RSPTA.37560347G }}</ref> the spontaneous generation of these combinatorial droplets may have played a role in early cellularization before the innovation of lipid vesicles. Protein function within and RNA function in the presence of certain polyester droplets was shown to be preserved within the droplets. Additionally, the droplets have scaffolding ability, by allowing lipids to assemble around them that may have prevented leakage of genetic materials.<br />
<br />
研究人员托尼·贾 Tony Jia和库罕·尚德吕 Kuhan Chandru提出,无膜聚酯液滴可能在生命起源中发挥了重要作用。鉴于生命起源以前的化学的 "混乱 "性质,这些组合液滴的自然发生可能在脂质小泡革新之前的早期细胞化中发挥了作用。研究表明,在某些聚酯液滴的存在下,液滴内的蛋白质功能和RNA功能得以保存。此外,该液滴具有支架能力,通过允许脂质在其周围组装,可能防止了遗传物质的泄漏。<br />
<br />
=== Proteinoid microspheres ===<br />
类蛋白微球体<br />
Fox observed in the 1960s that the proteinoids that he had synthesized could form cell-like structures that have been named "[[Proteinoid|proteinoid microspheres]]".<ref name="foxexp">{{cite web |url=http://nitro.biosci.arizona.edu/courses/EEB105/lectures/Origins_of_Life/origins.html |title=Part 4: Experimental studies of the origins of life |last=Walsh |first=J. Bruce |year=1995 |work=Origins of life |publisher=[[University of Arizona]] |location=Tucson, AZ |type=Lecture notes |archiveurl=https://web.archive.org/web/20080113152408/http://nitro.biosci.arizona.edu/courses/EEB105/lectures/Origins_of_Life/origins.html |archivedate=2008-01-13 |accessdate=2015-06-08}}</ref><br />
<br />
Fox在20世纪60年代观察到,他合成的类蛋白可以形成细胞状结构,被命名为 "类蛋白微球体"。<br />
<br />
The amino acids had combined to form [[proteinoid]]s, and the proteinoids had combined to form small globules that Fox called "microspheres". His proteinoids were not cells, although they formed clumps and chains reminiscent of [[cyanobacteria]], but they contained no functional [[nucleic acid]]s or any encoded information. Based upon such experiments, [[Colin Pittendrigh]] stated in 1967 that "laboratories will be creating a living cell within ten years," a remark that reflected the typical contemporary naivety about the complexity of cell structures.<ref>{{harvnb|Woodward|1969|p=287}}</ref><br />
<br />
氨基酸组合形成类蛋白,而类蛋白组合成小球,福克斯称之为 "微球体"。他的类蛋白不是细胞,虽然它们形成的团块和链子让人联想到蓝藻,但它们不含任何功能性核酸或任何编码信息。基于这样的实验,科林·布里斯顿 Colin Pittendrigh在1967年说:"实验室将在十年内创造出一个活细胞。"这句话反映了当代人对细胞结构复杂性的典型天真。<br />
<br />
=== Lipid world ===<br />
<br />
脂质世界<br />
<br />
{{Main|Gard model}}<br />
<br />
The [[Gard model|lipid world]] theory postulates that the first self-replicating object was [[lipid]]-like.<ref>{{cite web |url=http://www.weizmann.ac.il/molgen/Lancet/research/prebiotic-evolution |title=Systems Prebiology-Studies of the origin of Life |last=Lancet |first=Doron |date=30 December 2014 |website=The Lancet Lab |publisher=Department of Molecular Genetics; [[Weizmann Institute of Science]] |location=Rehovot, Israel |accessdate=2015-06-26 |url-status=live |archiveurl=https://web.archive.org/web/20150626180507/http://www.weizmann.ac.il/molgen/Lancet/research/prebiotic-evolution |archivedate=26 June 2015}}</ref><ref>{{cite journal |last1=Segré |first1=Daniel |last2=Ben-Eli |first2=Dafna |last3=Deamer |first3=David W. |last4=Lancet |first4=Doron |date=February 2001 |title=The Lipid World |url=http://www.weizmann.ac.il/molgen/Lancet/sites/molgen.Lancet/files/uploads/segre_lipid_world.pdf |journal=Origins of Life and Evolution of the Biosphere |volume=31 |issue=1–2 |pages=119–145 |doi=10.1023/A:1006746807104 |pmid=11296516 |bibcode=2001OLEB...31..119S |s2cid=10959497 |accessdate=2008-09-11 |url-status=live |archiveurl=https://web.archive.org/web/20150626225745/http://www.weizmann.ac.il/molgen/Lancet/sites/molgen.Lancet/files/uploads/segre_lipid_world.pdf |archivedate=26 June 2015}}</ref> It is known that phospholipids form [[lipid bilayer]]s in water while under agitation—the same structure as in cell membranes. These molecules were not present on early Earth, but other [[Amphiphile|amphiphilic]] long-chain molecules also form membranes. Furthermore, these bodies may expand (by insertion of additional lipids), and under excessive expansion may undergo spontaneous splitting which preserves the same size and composition of lipids in the two [[Offspring|progenies]]. The main idea in this theory is that the molecular composition of the lipid bodies is the preliminary way for information storage, and evolution led to the appearance of polymer entities such as RNA or DNA that may store information favourably. Studies on vesicles from potentially prebiotic amphiphiles have so far been limited to systems containing one or two types of amphiphiles. This in contrast to the output of simulated prebiotic chemical reactions, which typically produce very heterogeneous mixtures of compounds.<ref name="Chen 2010" /><br />
<br />
脂质世界理论认为,第一个自我复制的物体是类脂质的。众所周知,磷脂在水中搅拌时形成脂质双层--与细胞膜的结构相同。这些分子在早期地球上并不存在,但其他两亲性质的长链分子也会形成膜。此外,这些脂质体可能会膨胀(通过插入额外的脂质),在过度膨胀下可能会发生自发的分裂,从而在两个后代中保留了相同的大小和脂质的组成。这一理论的主要观点是,脂质体的分子组成是信息储存的初步方式,进化导致了如RNA或DNA等聚合物实体的出现,它们可能有利地储存信息。迄今为止,对来自潜在的前生物两亲化合物的囊泡的研究还仅限于含有一两种两亲化合物的系统。这与模拟的前生物化学反应的产出形成鲜明对比,前生物化学反应通常会产生非常异质的化合物的混合物。<br />
<br />
Within the hypothesis of a lipid bilayer membrane composed of a mixture of various distinct amphiphilic compounds there is the opportunity of a huge number of theoretically possible combinations in the arrangements of these amphiphiles in the membrane. Among all these potential combinations, a specific local arrangement of the membrane would have favoured the constitution of a hypercycle,<ref>{{cite journal |last1=Eigen |first1=Manfred |authorlink1=Manfred Eigen |last2=Schuster |first2=Peter |authorlink2=Peter Schuster |date=November 1977 |title=The Hypercycle. A Principle of Natural Self-Organization. Part A: Emergence of the Hypercycle |url=http://jaguar.biologie.hu-berlin.de/~wolfram/pages/seminar_theoretische_biologie_2007/literatur/schaber/Eigen1977Naturwissenschaften64.pdf |journal=Naturwissenschaften |volume=64 |issue=11 |pages=541–65|bibcode=1977NW.....64..541E |doi=10.1007/bf00450633 |pmid=593400 |accessdate=2015-06-13 |url-status=dead |archiveurl=https://web.archive.org/web/20160303194728/http://jaguar.biologie.hu-berlin.de/~wolfram/pages/seminar_theoretische_biologie_2007/literatur/schaber/Eigen1977Naturwissenschaften64.pdf |archivedate=3 March 2016}}<br />
<br />
在由各种不同的两亲化合物的混合物组成的脂质双层膜的假设中,这些两亲化合物在膜上的排列中有大量理论上可能的组合的机会。在所有这些潜在的组合中,膜的一个特定的局部排列将有利于超循环的构成,<br />
<br />
* {{cite journal |last1=Eigen |first1=Manfred |last2=Schuster |first2=Peter |date=July 1978 |title=The Hypercycle. A Principle of Natural Self-Organization. Part C: The Realistic Hypercycle |url=http://jaguar.biologie.hu-berlin.de/~wolfram/pages/seminar_theoretische_biologie_2007/literatur/schaber/Eigen1978Naturwissenschaften65b.pdf |journal=Naturwissenschaften |volume=65 |issue=7 |pages=341–369 |bibcode=1978NW.....65..341E |doi=10.1007/bf00439699 |s2cid=13825356 |accessdate=2015-06-13 |url-status=dead |archiveurl=https://web.archive.org/web/20160616180402/http://jaguar.biologie.hu-berlin.de/~wolfram/pages/seminar_theoretische_biologie_2007/literatur/schaber/Eigen1978Naturwissenschaften65b.pdf |archivedate=16 June 2016}}</ref><ref>{{cite journal |last1=Markovitch |first1=Omer |last2=Lancet |first2=Doron |date=Summer 2012 |title=Excess Mutual Catalysis Is Required for Effective Evolvability |journal=[[Artificial Life (journal)|Artificial Life]] |volume=18 |issue=3 |pages=243–266 |doi=10.1162/artl_a_00064|pmid=22662913 |s2cid=5236043 }}</ref> actually a positive [[feedback]] composed of two mutual catalysts represented by a membrane site and a specific compound trapped in the vesicle. Such site/compound pairs are transmissible to the daughter vesicles leading to the emergence of distinct [[Lineage (evolution)|lineages]] of vesicles which would have allowed Darwinian natural selection.<ref>{{cite journal |last=Tessera |first=Marc |year=2011 |title=Origin of Evolution ''versus'' Origin of Life: A Shift of Paradigm |journal=[[International Journal of Molecular Sciences]] |volume=12 |issue=6 |pages=3445–3458 |doi=10.3390/ijms12063445 |pmc=3131571 |pmid=21747687}} Special Issue: "Origin of Life 2011"</ref><br />
<br />
实际上是由两个相互的催化剂组成的正反馈,由一个膜位点和一个被困在囊泡中的特定化合物代表。这样的位点/化合物对可以传递给子囊泡,从而导致不同的囊泡谱系的出现,这将允许达尔文的自然选择。<br />
***讨论:这样的膜位点和化合物对,如何保证遗传性?***<br />
=== Protocells ===<br />
原始细胞<br />
{{Main|Protocell}}<br />
<br />
[[File:Phospholipids aqueous solution structures.svg|thumb|upright|The three main structures [[phospholipid]]s form spontaneously in solution: the [[liposome]] (a closed bilayer), the [[micelle]] and the bilayer.]]<br />
<br />
磷脂在溶液中自发形成的三个主要结构:脂质体(封闭的双层),胶束和双层。<br />
<br />
A protocell is a self-organized, self-ordered, spherical collection of [[lipid]]s proposed as a stepping-stone to the origin of life.<ref name="Chen 2010">{{cite journal |first1=Irene A. |last1=Chen |first2=Peter |last2=Walde |title=From Self-Assembled Vesicles to Protocells |journal=Cold Spring Harbor Perspectives in Biology |date=July 2010 |volume=2 |issue=7 |page=a002170 |doi=10.1101/cshperspect.a002170 |pmc=2890201 |pmid=20519344}}</ref> A central question in evolution is how simple protocells first arose and differed in reproductive contribution to the following generation driving the evolution of life. Although a functional protocell has not yet been achieved in a laboratory setting, there are scientists who think the goal is well within reach.<ref name="Exploring">{{cite web |url=http://exploringorigins.org/protocells.html |title=Exploring Life's Origins: Protocells |website=Exploring Life's Origins: A Virtual Exhibit |publisher=National Science Foundation |location=Arlington County, VA |accessdate=2014-03-18 |url-status=live |archiveurl=https://web.archive.org/web/20140228083459/http://exploringorigins.org/protocells.html |archivedate=28 February 2014}}</ref><ref name="Chen 2006">{{cite journal |last=Chen |first=Irene A. |date=8 December 2006 |title=The Emergence of Cells During the Origin of Life |journal=Science |volume=314 |issue=5805 |pages=1558–1559 |doi=10.1126/science.1137541 |pmid=17158315 |doi-access=free }}</ref><ref name="Discover 2004">{{cite journal |last=Zimmer |first=Carl |authorlink=Carl Zimmer |date=26 June 2004 |title=What Came Before DNA? |url=http://discovermagazine.com/2004/jun/cover |journal=Discover |url-status=live |archiveurl=https://web.archive.org/web/20140319001351/http://discovermagazine.com/2004/jun/cover |archivedate=19 March 2014}}</ref><br />
<br />
原始细胞是一种自组织、自排序、球形的脂质集合,被提议作为生命起源的踏脚石。进化论中的一个核心问题是简单的原始细胞是如何首先产生的,并对下一代的繁殖贡献不同,推动生命的进化。虽然在实验室环境中还没有实现功能性的原始细胞,但有科学家认为这个目标是可以实现的。<br />
<br />
Self-assembled [[Vesicle (biology and chemistry)|vesicles]] are essential components of primitive cells.<ref name="Chen 2010" /> The [[second law of thermodynamics]] requires that the universe move in a direction in which [[entropy]] increases, yet life is distinguished by its great degree of organization. Therefore, a boundary is needed to separate [[Metabolism|life processes]] from non-living matter.<ref name="SciAm 2007">{{cite journal |last=Shapiro |first=Robert |authorlink=Robert Shapiro (chemist) |date=June 2007 |title=A Simpler Origin for Life |url=http://www.scientificamerican.com/article/a-simpler-origin-for-life/ |journal=Scientific American |volume=296 |issue=6 |pages=46–53 |doi=10.1038/scientificamerican0607-46 |pmid=17663224 |accessdate=2015-06-15 |bibcode=2007SciAm.296f..46S |url-status=live |archiveurl=https://web.archive.org/web/20150614000643/http://www.scientificamerican.com/article/a-simpler-origin-for-life/ |archivedate=14 June 2015}}</ref> Researchers Irene Chen and Szostak amongst others, suggest that simple physicochemical properties of elementary protocells can give rise to essential cellular behaviours, including primitive forms of differential reproduction competition and energy storage. Such cooperative interactions between the membrane and its encapsulated contents could greatly simplify the transition from simple replicating molecules to true cells.<ref name="Chen 2006" /> Furthermore, competition for membrane molecules would favour stabilized membranes, suggesting a selective advantage for the evolution of cross-linked fatty acids and even the [[phospholipid]]s of today.<ref name="Chen 2006" /> Such [[micro-encapsulation]] would allow for metabolism within the membrane, the exchange of small molecules but the prevention of passage of large substances across it.<ref>{{harvnb|Chang|2007}}</ref> The main advantages of encapsulation include the increased [[solubility]] of the contained cargo within the capsule and the storage of energy in the form of an [[electrochemical gradient]].<br />
<br />
自组装囊泡是原始细胞的必要组成部分。热力学第二定律要求宇宙向熵增加的方向运动,然但生命以其组织程度高而著称。因此,需要一个边界来将生命过程与非生命物质分开。研究人员艾琳·陈 Irene Chen和绍斯塔克 Szostak等人认为,基本原细胞的简单物理化学特性可以引起基本的细胞行为,包括原始形式的差异繁殖竞争和能量储存。膜与包裹物之间的这种合作相互作用可以大大简化从简单复制分子到真正细胞的过渡。此外,对膜分子的竞争将有利于稳定的膜,这表明交联脂肪酸甚至今天的磷脂的进化具有选择性优势。 这种微胶囊将允许膜内的新陈代谢,小分子的交换,但防止大物质穿过膜。胶囊化的主要优势包括胶囊内所含货物的溶解度增加,以及以电化学梯度的形式储存能量。讨论***为什么胶囊内的货物的溶解度会增加呢?***<br />
<br />
A 2012 study led by Mulkidjanian of the [[University of Osnabrück]], suggests that inland pools of condensed and cooled geothermal vapor have the ideal characteristics for the origin of life.<ref name="Switek 2012">{{cite news |last=Switek |first=Brian |date=13 February 2012 |title=Debate bubbles over the origin of life |work=Nature |location=London |publisher=Nature Publishing Group |doi=10.1038/nature.2012.10024}}</ref> Scientists confirmed in 2002 that by adding a [[montmorillonite]] clay to a solution of fatty acid micelles (lipid spheres), the clay sped up the rate of vesicles formation 100-fold.<ref name="Discover 2004" /> Furthermore, recent studies have found that the repeated actions of dehydration and rehydration trapped biomolecules like RNA inside the lipid protocells found within hot springs and providing the necessary preconditions for evolution by natural selection.<ref>{{Cite web|last=z3530495|date=2020-05-05|title='When chemistry became biology': looking for the origins of life in hot springs|url=https://newsroom.unsw.edu.au/news/science-tech/when-chemistry-became-biology-looking-origins-life-hot-springs|access-date=2020-10-12|website=UNSW Newsroom}}</ref><br />
<br />
奥斯纳布吕克大学的穆尔基贾尼安 Mulkidjanian领导的一项2012年的研究表明,冷凝和冷却的地热蒸汽的内陆池具有生命起源的理想特征。科学家在2002年证实,通过在脂肪酸胶束(脂质球)溶液中加入蒙脱石粘土,粘土将囊泡形成的速度加快了100倍。此外,最近的研究还发现,脱水和补水的反复作用将RNA等生物分子困在了温泉内发现的脂质原始细胞内,为自然选择的进化提供了必要的前提条件。<br />
<br />
=== Lipid vesicles formation in fresh water ===<br />
<br />
淡水中脂质泡的形成 <br />
<br />
[[Bruce Damer]] and [[David Deamer]] have come to the conclusion that [[cell membrane]]s cannot be formed in salty [[seawater]], and must therefore have originated in freshwater. Before the continents formed, the only dry land on Earth would be volcanic islands, where rainwater would form ponds where lipids could form the first stages towards cell membranes. These predecessors of true cells are assumed to have behaved more like a [[superorganism]] rather than individual structures, where the porous membranes would house molecules which would leak out and enter other protocells. Only when true cells had evolved would they gradually adapt to saltier environments and enter the ocean.<ref>{{cite journal |last1=Damer |first1=Bruce |last2=Deamer |first2=David |date=13 March 2015 |title=Coupled Phases and Combinatorial Selection in Fluctuating Hydrothermal Pools: A Scenario to Guide Experimental Approaches to the Origin of Cellular Life |journal=Life |volume=5 |issue=1 |pages=872–887 |doi=10.3390/life5010872 |pmc=4390883 |pmid=25780958}}</ref><br />
<br />
布鲁斯·达默Bruce Damer和大卫·迪默David Deamer得出的结论是,细胞膜不可能在咸咸的海水中形成,因此必须起源于淡水。在大陆形成之前,地球上唯一干燥的陆地应该是火山岛,雨水会在那里形成池塘,脂质可以在那里形成走向细胞膜的第一个阶段。这些真正细胞的前身被认为表现得更像一个超个体,而不是个体的结构,多孔的膜会容纳分子,这些分子会漏出并进入其他原细胞。只有当真细胞进化后,它们才会逐渐适应较咸的环境,进入海洋。<br />
<br />
=== Vesicles consisting of mixtures of RNA-like biochemicals ===<br />
<br />
由RNA类生化物质的混合物组成的囊泡<br />
Another protocell model is the [[Jeewanu]]. First synthesized in 1963 from simple minerals and basic organics while exposed to sunlight, it is still reported to have some metabolic capabilities, the presence of [[semipermeable membrane]], amino acids, phospholipids, [[carbohydrate]]s and RNA-like molecules.<ref name="Grote 2011">{{cite journal |last=Grote |first=Mathias |date=September 2011 |title=''Jeewanu'', or the 'particles of life' |url=http://www.ias.ac.in/jbiosci/grote_3677.pdf |journal=[[Journal of Biosciences]] |volume=36 |issue=4 |pages=563–570 |doi=10.1007/s12038-011-9087-0 |pmid=21857103 |s2cid=19551399 |accessdate=2015-06-15 |url-status=live |archiveurl=https://web.archive.org/web/20150924050938/http://www.ias.ac.in/jbiosci/grote_3677.pdf |archivedate=24 September 2015}}</ref><ref name="Gupta 2013">{{cite journal |last1=Gupta |first1=V.K. |last2=Rai |first2=R.K. |date=August 2013 |title=Histochemical localisation of RNA-like material in photochemically formed self-sustaining, abiogenic supramolecular assemblies 'Jeewanu' |url=https://www.academia.edu/9439398 |journal=International Research Journal of Science & Engineering |volume=1 |issue=1 |pages=1–4|accessdate=2015-06-15 |url-status=live |archiveurl=https://web.archive.org/web/20170628001930/http://www.academia.edu/9439398/Histochemical_Localisation_of_RNA_like_material_in_photochemically_formed_self-sustaining_abiogenic_supramolecular_assemblis_Jeewanu_ |archivedate=28 June 2017}}</ref> However, the nature and properties of the Jeewanu remains to be clarified.<br />
<br />
另一种原细胞模型是Jeewanu。1963年首次由简单的矿物质和基本有机物在阳光下合成,据报道,它仍具有一定的新陈代谢能力,存在半透膜、氨基酸、磷脂、碳水化合物和RNA类分子。<br />
<br />
Electrostatic interactions induced by short, positively charged, hydrophobic peptides containing 7 amino acids in length or fewer, can attach RNA to a vesicle membrane, the basic cell membrane.<ref>{{cite news |last=Welter |first=Kira |date=10 August 2015 |title=Peptide glue may have held first protocell components together |url=http://www.rsc.org/chemistryworld/2015/08/peptide-glue-rna-may-have-held-first-protocells-together |work=Chemistry World |type=News |location=London |publisher=Royal Society of Chemistry |accessdate= 2015-08-29 |url-status=live |archiveurl=https://web.archive.org/web/20150905234238/http://www.rsc.org/chemistryworld/2015/08/peptide-glue-rna-may-have-held-first-protocells-together |archivedate=5 September 2015}}</ref><ref>{{cite journal |last1=Kamat |first1=Neha P. |last2=Tobé |first2=Sylvia |last3=Hill |first3=Ian T. |last4=Szostak |first4=Jack W. |authorlink4=Jack W. Szostak |title=Electrostatic Localization of RNA to Protocell Membranes by Cationic Hydrophobic Peptides |date=29 July 2015 |journal=Angewandte Chemie International Edition |doi=10.1002/anie.201505742 |pmid=26223820 |pmc=4600236 |volume=54 |issue=40 |pages=11735–11739}}</ref><br />
<br />
由长度为7个氨基酸或更少的带正电荷的疏水性短肽引起的静电相互作用,可以将RNA附着在囊膜上,即基本细胞膜上。<br />
<br />
=== Metal-sulfide precipitates ===<br />
<br />
金属硫化物沉淀物<br />
<br />
William Martin and [[Michael Russell (scientist)|Michael Russell]] have suggested < blockquote >. . . . that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,..."<ref name="Martin2003">{{cite journal |last1=Martin |first1=William |authorlink1=William F. Martin |last2=Russell |first2=Michael J. |date=29 January 2003 |title=On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells |journal=Philosophical Transactions of the Royal Society B |volume=358 |issue=1429 |pages=59–83; discussion 83–85 |doi=10.1098/rstb.2002.1183|pmid=12594918 |pmc=1693102}}</ref> < /blockquote ><br />
<br />
威廉·马丁 William Martin和迈克尔·拉塞尔 Michael Russell说<br />
<br />
......生命是在一个渗流点热液丘中的结构化一硫化铁沉淀物中演化出来的,其氧化还原、pH值和温度梯度介于富含硫化物的热液和冥古代洋底的含铁(II)水之间。在渗透点金属硫化物沉淀物化石中观察到的自然生成的三维分隔表明,这些无机分隔是在自由生活的原核生物中发现的细胞壁和细胞膜的前身。已知FeS和NiS能够催化一氧化碳和甲基硫化物(热液的成分)合成乙酰-甲基硫化物,这表明前生物合成发生在这些金属硫化物壁隔室的内表面,......"<br />
== Pertinent geological environments ==<br />
<br />
相关地质环境<br />
===Darwin's little pond===<br />
<br />
Darwin的小池塘 <br />
<br />
An early concept, that life originated from non-living matter in slow stages, appeared in [[Herbert Spencer]]'s 1864–1867 book ''Principles of Biology''. In 1879 [[William Turner Thiselton-Dyer]] referred to this in a paper "On spontaneous generation and evolution". On 1 February 1871 [[Charles Darwin]] wrote about these publications to [[Joseph Dalton Hooker|Joseph Hooker]], and set out his own speculation,<ref name="Darwin DCP-LETT-7471">{{cite web | title=Letter no. 7471, Charles Darwin to Joseph Dalton Hooker, 1 February (1871) | website=Darwin Correspondence Project | date= | url=https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml | access-date=7 July 2020}}</ref><ref>{{cite web|url=https://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|title=Origin and Evolution of Life on a Frozen Earth|last=Priscu|first=John C.|authorlink=John Charles Priscu|publisher=[[National Science Foundation]]|location=Arlington County, VA|archiveurl=https://web.archive.org/web/20131218070241/http://www.nsf.gov/news/special_reports/darwin/textonly/polar_essay1.jsp|archivedate=18 December 2013|url-status=live|accessdate=2014-03-01}}</ref> suggesting that the original spark of life may have begun in a < blockquote >warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, {{sic|hide=y|&c.}}, present, that a {{sic|hide=y|[[protein]]e}} compound was chemically formed ready to undergo still more complex changes.< /blockquote > He went on to explain that < blockquote >at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.< /blockquote ><br />
<br />
一个早期的概念,即生命在缓慢的阶段中起源于非生命物质,出现在赫伯特·斯宾塞 Herbert Spencer 1864-1867年的《生物学原理》一书中。1879年威廉·特纳·希塞尔顿-代尔 William Turner Thiselton-Dyer在论文"论自然发生和演化"中提到了这一点。1871年2月1日,Charles Darwin将这些出版物写信给约瑟夫·胡克 Joseph Hooker,并提出了自己的推测,认为生命的最初火花可能是始于<br />
<br />
<br />
温暖的小池塘,加上各种氨和磷盐,光、热、电等的存在,一种蛋白质化合物已经在化学上形成,准备进行更复杂的变化。<br />
<br />
<br />
他继续解释说,<br />
<br />
< blockquote ><br />
在今天,这种物质会被立即吞噬或吸收,而在生物形成之前是不会有这种情况的。<br />
< blockquote ><br />
<br />
{{harvnb|Darwin|1887|p=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F1452.3&pageseq=30 18]}}:<br />
<br />
Darwin 1887年,第18页。<br />
<br />
It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present. But if (and oh! what a big if!) we could conceive in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, {{sic|&c.|hide=y}}, present, that a {{sic|[[protein]]e|hide=y}} compound was chemically formed ready to undergo still more complex changes, at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.<br />
<br />
人们常说,现在已经具备了生物体第一次生产的所有条件,而这些条件本来是可能存在的。但是,如果(哦!多么大的如果啊!)我们可以设想在某个温暖的小池塘里,在各种氨和磷盐、光、热、电等条件存在的情况下,一种蛋白质化合物被化学形成,准备进行更复杂的变化,在现在,这种物质会立即被吞噬或吸收,这在生物形成之前是不会出现的。<br />
<br />
— Darwin, 1 February 1871<br />
—达尔文,1871年2月1日<br />
<br />
More recent studies, in 2017, support the notion that life may have begun right after the Earth was formed as RNA molecules emerging from "warm little ponds".<ref name="IND-20171002">{{cite web |last=Johnston |first=Ian |title=Life first emerged in 'warm little ponds' almost as old as the Earth itself – Darwin's famous idea backed by new scientific study |url=https://www.independent.co.uk/news/science/origins-life-ponds-organisms-earth-age-study-a7978906.html |date=2 October 2017 |work=[[The Independent]] |accessdate=2 October 2017 |url-status=live |archiveurl=https://web.archive.org/web/20171003003027/http://www.independent.co.uk/news/science/origins-life-ponds-organisms-earth-age-study-a7978906.html |archivedate=3 October 2017}}</ref><br />
<br />
2017年的最新研究支持这样的观点:生命可能在地球形成后就开始了,因为RNA分子从"温暖的小池塘"中出现。<br />
<br />
===Volcanic hot springs and hydrothermal vents, shallow or deep===<br />
<br />
浅层或深层的火山温泉和热液喷口<br />
<br />
{{for|branching of Bacteria phyla|Bacterial phyla}}<br />
<br />
Martin Brazier has shown that early micro-fossils came from a hot world of gases such as [[methane]], [[ammonia]], [[carbon dioxide]] and [[hydrogen sulphide]], which are toxic to much current life.<ref><br />
<br />
M.D> Brasier (2012), "Secret Chambers: The Inside Story of Cells and Complex Life" (Oxford Uni Press), p.298</ref> Another analysis of the conventional threefold tree of life shows thermophilic and hyperthermophilic [[bacteria]] and [[archaea]] are closest to the root, suggesting that life may have evolved in a hot environment.<ref>Ward, Peter & Kirschvink, Joe, op cit, p. 42</ref><br />
<br />
马丁·布劳泽尔 Martin Brazier曾表明,早期的微体化石来自于甲烷、氨、二氧化碳和硫化氢等气体的高温世界,这些气体对目前的许多生命都是有毒的。另一种对传统的三重生命树的分析表明,嗜热和嗜高温的细菌和古细菌最接近根部,这表明生命可能是在高温环境中进化的。<br />
<br />
===Deep sea hydrothermal vents===<br />
<br />
深海热液喷口<br />
[[File:Blacksmoker in Atlantic Ocean.jpg|thumb|upright|Deep-sea hydrothermal vent or [[black smoker]]]]<br />
<br />
深海热液喷口或海底黑烟柱<br />
The deep sea vent, or alkaline [[hydrothermal vent]], theory posits that life may have begun at submarine hydrothermal vents,<ref name=":1">{{Cite journal|author1=Colín-García, M.|author2=A. Heredia|author3=G. Cordero|author4=A. Camprubí|author5=A. Negrón-Mendoza|author6=F. Ortega-Gutiérrez|author7=H. Berald|author8=S. Ramos-Bernal|year=2016|title=Hydrothermal vents and prebiotic chemistry: a review|url=http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|journal=Boletín de la Sociedad Geológica Mexicana|volume=68|issue=3|pages=599–620|url-status=live|archiveurl=https://web.archive.org/web/20170818175803/http://boletinsgm.igeolcu.unam.mx/bsgm/index.php/component/content/article/309-sitio/articulos/cuarta-epoca/6803/1620-6803-13-colin|archivedate=18 August 2017|doi=10.18268/BSGM2016v68n3a13|doi-access=free}}</ref><ref name="hydrothermal vents NASA 2014">{{cite web|url=https://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |title=Hydrothermal Vents Could Explain Chemical Precursors to Life |last=Schirber |first=Michael |date=24 June 2014 |website=NASA Astrobiology: Life in the Universe |publisher=NASA |accessdate=2015-06-19 |url-status=dead |archiveurl=https://web.archive.org/web/20141129051724/http://astrobiology.nasa.gov/articles/2014/6/24/hydrothermal-vents-could-explain-chemical-precursors-to-life/ |archivedate=29 November 2014}}</ref> Martin and Russell have suggested < blockquote >that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyze the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments,...<ref name="Martin2003" />< /blockquote > These form where hydrogen-rich fluids emerge from below the sea floor, as a result of [[Serpentinite|serpentinization]] of ultra-[[mafic]] [[olivine]] with seawater and a pH interface with carbon dioxide-rich ocean water. The vents form a sustained chemical energy source derived from redox reactions, in which electron donors (molecular hydrogen) react with electron acceptors (carbon dioxide); see [[Iron–sulfur world theory]]. These are highly [[exothermic reaction]]s.<ref name=":1" />{{efn|The reactions are:<br /><br />
<br />
深海喷口或碱性热液喷口理论认为生命可能始于海底热液喷口,Martin和Russell认为<br />
<br />
< blockquote ><br />
<br />
生命是在一个渗流点热液丘中的结构化一硫化铁沉淀物中演化出来的,其氧化还原、pH值和温度梯度介于富含硫化物的热液和冥古代洋底的含铁(II)水之间。在渗流点金属硫化物沉淀物化石中观察到的自然生成的三维分隔表明,这些无机分隔是自由生活的原核生物中发现的细胞壁和膜的前体。已知FeS和NiS能够催化一氧化碳和甲基硫化物(热液的成分)合成乙酰-甲基硫化物,这表明前生物合成发生在这些金属硫化物壁隔室的内表面,<br />
< blockquote ><br />
<br />
这些喷口形成于海底富氢液体渗出的地方,是超镁铁质橄榄石与海水发生蛇纹石化以及与富含二氧化碳的海水的pH值界面的结果。这些喷口形成了一个来自氧化还原反应的持续化学能源,其中电子供体(分子氢)与电子受体(二氧化碳)发生反应;见铁-硫世界理论。这些都是高度放热的反应。<br />
<br />
Russell demonstrated that alkaline vents created an abiogenic [[Proton electromotive force|proton motive force]] (PMF) [[Chemiosmosis|chemiosmotic]] gradient,<ref name="Martin2003" /> in which conditions are ideal for an abiogenic hatchery for life. Their microscopic compartments "provide a natural means of concentrating organic molecules," composed of iron-sulfur minerals such as [[mackinawite]], endowed these mineral cells with the catalytic properties envisaged by [[Günter Wächtershäuser]].<ref name="Lane 2009" /> This movement of ions across the membrane depends on a combination of two factors:<br />
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Russell证明,碱性喷口创造了一个非生物质子动力(PMF)化学渗透的梯度,其中的条件是理想的非生物生命孵化器。它们的微观隔间"提供了集中有机分子的天然手段",由铁硫矿物组成,如马基诺矿,赋予这些矿物小室以金特·沃特肖泽 Günter Wächtershäuser设想的催化特性。这种离子在膜上的运动取决于两个因素的组合:<br />
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# [[Diffusion]] force caused by concentration gradient—all particles including ions tend to diffuse from higher concentration to lower.<br />
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由浓度梯度引起的扩散力--包括离子在内的所有粒子都倾向于从高浓度向低浓度扩散。<br />
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# Electrostatic force caused by electrical potential gradient—[[cations]] like [[proton]]s H<sup>+</sup> tend to diffuse down the electrical potential, [[anions]] in the opposite direction.<br />
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电位梯度引起的静电力--质子H<sup>+</sup>等阳离子倾向于顺着电位扩散,阴离子则相反。<br />
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These two gradients taken together can be expressed as an [[electrochemical gradient]], providing energy for abiogenic synthesis. The proton motive force can be described as the measure of the potential energy stored as a combination of proton and voltage gradients across a membrane (differences in proton concentration and electrical potential).<br />
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这两个梯度综合起来可以表示为电化学梯度,为非生物合成提供能量。质子动力可以描述为质子和电压跨膜梯度的组合(质子浓度和电位的差异)所储存的势能的度量。<br />
<br />
Szostak suggested that geothermal activity provides greater opportunities for the origination of life in open lakes where there is a buildup of minerals. In 2010, based on spectral analysis of sea and hot mineral water, Ignat Ignatov and Oleg Mosin demonstrated that life may have predominantly originated in hot mineral water. The hot mineral water that contains [[bicarbonate]] and [[calcium]] ions has the most optimal range.<ref>{{cite journal |last1=Ignatov |first1=Ignat |last2=Mosin |first2=Oleg V. |year=2013 |title=Possible Processes for Origin of Life and Living Matter with modeling of Physiological Processes of Bacterium ''Bacillus Subtilis'' in Heavy Water as Model System |journal=Journal of Natural Sciences Research |volume=3 |issue=9 |pages=65–76}}</ref> This case is similar to the origin of life in hydrothermal vents, but with bicarbonate and calcium ions in hot water. This water has a pH of 9–11 and is possible to have the reactions in seawater. According to [[Melvin Calvin]], certain reactions of condensation-dehydration of amino acids and nucleotides in individual blocks of peptides and nucleic acids can take place in the primary hydrosphere with pH 9–11 at a later evolutionary stage.<ref>{{harvnb|Calvin|1969}}</ref> Some of these compounds like [[Hydrogen cyanide|hydrocyanic acid]] (HCN) have been proven in the experiments of Miller. This is the environment in which the [[stromatolite]]s have been created. David Ward of [[Montana State University]] described the formation of stromatolites in hot mineral water at the [[Yellowstone National Park]]. Stromatolites survive in hot mineral water and in proximity to areas with volcanic activity.<ref>{{cite journal |last=Schirber |first=Michael |date=1 March 2010 |title=First Fossil-Makers in Hot Water |url=http://www.astrobio.net/news-exclusive/first-fossil-makers-in-hot-water/ |journal=[[Astrobiology Magazine]] |accessdate=2015-06-19 |url-status=live |archiveurl=https://web.archive.org/web/20150714085640/http://www.astrobio.net/news-exclusive/first-fossil-makers-in-hot-water/ |archivedate=14 July 2015}}</ref> Processes have evolved in the sea near geysers of hot mineral water. <br />
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Szostak提出,在有矿物质堆积的开放湖泊中,地热活动为生命的起源提供了更大的机会。2010年,伊格纳特·伊格纳托夫 Ignat Ignatov和奥列格·莫辛Oleg Mosin根据对海水和热矿泉水的光谱分析,证明生命可能主要起源于热矿泉水。含有碳酸氢盐和钙离子的热矿泉水具有最理想的范围。这种情况类似于热液喷口中的生命起源,但热水中含有碳酸氢盐和钙离子。这种水的pH值为9-11,有可能在海水中发生反应。根据梅尔文·卡尔文 Melvin Calvin的观点,在更后的进化阶段,在pH值为9-11的原生水球中,可能发生某些氨基酸和核苷酸在多肽和核酸各个区段中的脱水-缩合反应。其中一些化合物如氢氰酸(HCN)已经在Miller的实验中得到证明。这就是产生叠层石的环境。蒙大拿州立大学的大卫·沃德 David Ward描述了黄石国家公园的热矿泉水中的叠层石的形成。叠层石存在于热矿泉水中和靠近火山活动的地区。这些过程是在热矿泉水的间歇泉附近的海中演化的。***2011年,东京大学的Tadashi Sugawara在热水中创造了一个原生细胞。***缺乏对应英文<br />
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Experimental research and computer modelling suggest that the surfaces of mineral particles inside hydrothermal vents have catalytic properties similar to those of enzymes and are able to create simple organic molecules, such as [[methanol]] (CH<sub>3</sub>OH) and [[Formic acid|formic]], [[Acetic acid|acetic]] and [[Pyruvic acid|pyruvic]] acid out of the dissolved CO<sub>2</sub> in the water.<ref name="organics">{{cite press release |last=Usher |first=Oli |date=27 April 2015 |title=Chemistry of seabed's hot vents could explain emergence of life |url=https://www.ucl.ac.uk/silva/mathematical-physical-sciences/maps-news-publication/maps1526 |publisher=[[University College London]] |accessdate=2015-06-19 |archive-url=https://web.archive.org/web/20150620012231/https://www.ucl.ac.uk/silva/mathematical-physical-sciences/maps-news-publication/maps1526 |archive-date=20 June 2015 |url-status=dead}}</ref><ref>{{cite journal |last1=Roldan |first1=Alberto |last2=Hollingsworth |first2=Nathan |last3=Roffey |first3=Anna |last4=Islam |first4=Husn-Ubayda |last5=Goodall |first5=Josephine B. M. |last6=Catlow |first6=C. Richard A. |authorlink6=Richard Catlow |last7=Darr |first7=Jawwad A. |last8=Bras |first8=Wim |last9=Sankar |first9=Gopinathan |last10=Holt |first10=Katherine B. |last11=Hogarth |first11=Graeme |last12=de Leeuw |first12=Nora Henriette |display-authors=4 |date=May 2015 |title=Bio-inspired CO2 conversion by iron sulfide catalysts under sustainable conditions |url=http://pubs.rsc.org/en/content/articlepdf/2015/cc/c5cc02078f|journal=Chemical Communications |volume=51 |issue=35 |pages=7501–7504 |doi=10.1039/C5CC02078F |pmid=25835242 |accessdate=2015-06-19 |url-status=live |archiveurl=https://web.archive.org/web/20150620003943/http://pubs.rsc.org/en/content/articlepdf/2015/cc/c5cc02078f |archivedate=20 June 2015|doi-access=free }}</ref><br />
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实验研究和计算机建模表明,热液喷口内的矿物颗粒表面具有类似酶的催化特性,能够从水中溶解的二氧化碳中制造出简单的有机分子,如甲醇(CH<sub>3</sub>OH)和甲酸、乙酸和丙酮酸。<br />
<br />
The research reported above by Martin in 2016 supports the thesis that life arose at hydrothermal vents,<ref>{{cite journal | last1 = Baross | first1 = J.A. | last2 = Hoffman | first2 = S.E. | year = 1985 | title = Submarine hydrothermal vents and associated gradient environments as sites for the origin and evolution of life | journal = Origins LifeEvol. B | volume = 15 | issue = 4 | pages = 327–345 | doi=10.1007/bf01808177| bibcode = 1985OrLi...15..327B | s2cid = 4613918 }}</ref><ref>{{cite journal | last1 = Russell | first1 = M.J. | last2 = Hall | first2 = A.J. | year = 1997 | title = The emergence of life from iron monosulphide bubbles at a submarine hydrothermal redox and pH front | journal = Journal of the Geological Society| volume = 154 | issue = 3 | pages = 377–402 | doi=10.1144/gsjgs.154.3.0377| pmid = 11541234 | bibcode = 1997JGSoc.154..377R | s2cid = 24792282 }}</ref> that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin<ref>{{cite journal | last1 = Amend | first1 = J.P. | last2 = LaRowe | first2 = D.E. | last3 = McCollom | first3 = T.M. | last4 = Shock | first4 = E.L. | year = 2013 | title = The energetics of organic synthesis inside and outside the cell | journal = Phil. Trans. R. Soc. Lond. B | volume = 368 | issue = 1622 | page = 20120255 | doi=10.1098/rstb.2012.0255| pmid = 23754809 | pmc = 3685458 }}</ref><ref>{{cite journal | last1 = Shock | first1 = E.L. | last2 = Boyd | first2 = E.S. | year = 2015 | title = Geomicrobiology and microbial geochemistry:principles of geobiochemistry | journal = Elements | volume = 11 | pages = 389–394 | doi = 10.2113/gselements.11.6.395 }}</ref> and that the founding lineages of the archaea and bacteria were H2-dependent autotrophs that used CO2 as their terminal acceptor in energy metabolism.<ref>{{cite journal | last1 = Martin | first1 = W. | last2 = Russell | first2 = M.J. | year = 2007 | title = On the origin of biochemistry at an alkaline hydrothermal vent | journal = Phil. Trans. R. Soc. Lond. B | volume = 362 | issue = 1486 | pages = 1887–1925 | doi = 10.1098/rstb.2006.1881 | pmid = 17255002 | pmc = 2442388 }}</ref> Martin suggests, based upon this evidence that [[LUCA]] "may have depended heavily on the geothermal energy of the vent to survive".<ref>Nature, Vol 535, 28 July 2016. p.468</ref><br />
<br />
Martin在2016年报告的上述研究支持这样的论点,即生命产生于热液喷口,地壳中由岩石-水相互作用驱动的非平衡热力学自发化学作用是生命起源的基础,古细菌和细菌的创始系是依赖H2的自养生物,它们在能量代谢中使用CO2作为终端接受体。Martin根据这些证据提出,LUCA "可能严重依赖喷口的地热能而生存"。<br />
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=== Fluctuating hydrothermal pools on volcanic islands or proto-continents ===<br />
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火山岛或原大陆上的波动性热液池<br />
<br />
Mulkidjanian and co-authors think that the marine environments did not provide the ionic balance and composition universally found in cells, as well as of ions required by essential proteins and ribozymes found in virtually all living organisms, especially with respect to K<sup>+</sup>/Na<sup>+</sup> ratio, Mn<sup>2+</sup>, Zn<sup>2+</sup> and phosphate concentrations. The only known environments that mimic the needed conditions on Earth are found in terrestrial hydrothermal pools fed by steam vents.<ref name=":1" /> Additionally, mineral deposits in these environments under an anoxic atmosphere would have suitable pH (as opposed to current pools in an oxygenated atmosphere), contain precipitates of sulfide minerals that block harmful UV radiation, have wetting/drying cycles that concentrate substrate solutions to concentrations amenable to spontaneous formation of polymers of nucleic acids, polyesters<ref>{{cite journal |last1=Chandru |first1=Kuhan |last2=Guttenberg |first2=Nicholas |last3=Giri |first3=Chaitanya |last4=Hongo |first4=Yayoi |last5=Butch |first5=Christopher |last6=Mamajanov |first6=Irena |last7=Cleaves |first7=H. James |title=Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries |journal=Communications Chemistry |date=31 May 2018 |volume=1 |issue=1 |doi=10.1038/s42004-018-0031-1 |doi-access=free }}</ref> and depsipeptides,<ref>{{cite journal |last1=Forsythe |first1=Jay G |last2=Yu |first2=Sheng-Sheng |last3=Mamajanov |first3=Irena |last4=Grover |first4=Martha A |last5=Krishnamurthy |first5=Ramanarayanan |last6=Fernández |first6=Facundo M |last7=Hud |first7=Nicholas V |title=Ester-Mediated Amide Bond Formation Driven by Wet–Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth |journal=Angewandte Chemie (International ed. In English) |date=17 August 2015 |volume=54 |issue=34 |pages=9871–9875 |doi=10.1002/anie.201503792 |pmid=26201989 |pmc=4678426 }}</ref> both by chemical reactions in the hydrothermal environment, as well as by exposure to [[UV light]] during transport from vents to adjacent pools. Their hypothesized pre-biotic environments are similar to the deep-oceanic vent environments most commonly hypothesized, but add additional components that help explain peculiarities found in reconstructions of the [[Last Universal Common Ancestor]] (LUCA) of all living organisms.<ref>{{cite journal |last1=Mulkidjanian |first1=Armid |last2=Bychkov |first2=Andrew |last3=Dibrova |first3=Daria |last4=Galperin |first4=Michael |last5=Koonin |first5=Eugene |date=3 April 2012 |title=Origin of first cells at terrestrial, anoxic geothermal fields |journal=PNAS |volume=109 |issue=14 |pages=E821–E830 |doi=10.1073/pnas.1117774109 |pmid=22331915 |pmc=3325685|bibcode=2012PNAS..109E.821M }}</ref><br />
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Mulkidjanian和其合著者认为,海洋环境没有提供细胞中普遍存在的离子平衡和组成,也没有提供几乎所有生物体中基本蛋白质和核酶所需的离子,特别是K<sup>+</sup>/Na<sup>+</sup>比率、Mn<sup>2+</sup>、Zn<sup>2+</sup>和磷酸盐浓度。唯一已知的模拟地球上所需条件的环境是在由蒸汽喷口供给的陆地热液池中发现的。此外,这些环境中的矿藏在缺氧大气下会有合适的pH值(而不是目前在含氧大气下的池子),含有能阻挡有害紫外线辐射的硫化物矿物质沉淀物,有湿润/干燥循环,能将基质溶液浓缩到适合自发形成多聚核酸、聚酯和缩肽的浓度,这些都是通过热液环境中的化学反应,以及通过从喷口向相邻池子运输过程中暴露在紫外线下形成的。他们推测的前生物环境与通常推测的深海喷口环境相似,但增加了额外的成分,有助于解释在重建所有生物的最后普遍共同祖先(LUCA)中发现的奇特之处。<br />
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Colín-García ''et al.'' (2016) discuss the advantages and disadvantages of hydrothermal vents as primitive environments.<ref name=":1"/> They mention the exergonic reactions in such systems could have been a source of free energy that promoted chemical reactions, additional to their high mineralogical diversity which implies the induction of important chemical gradients, thus favoring the interaction between electron donors and acceptors. Colín-García ''et al.'' (2016) also summarize a set of experiments proposed to test the role of hydrothermal vents in prebiotic synthesis.<ref name=":1"/><br />
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科林-加西亚 Colín-García“等人”(2016)讨论了热液喷口作为原始环境的优势和劣势。他们提到,这种系统中的放能反应可能是促进化学反应的一种自由能来源,此外,它们的矿物学多样性很高,这意味着重要的化学梯度的诱导,从而有利于电子供体和受体之间的相互作用。Colín-García等(2016)还总结了一组被提议用于测试热液喷口在前生物合成中的作用的实验。<br />
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===Volcanic ash in the ocean===<br />
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海洋中的火山灰<br />
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[[Geoffrey W. Hoffmann]] has argued that a complex nucleation event as the origin of life involving both polypeptides and nucleic acid is compatible with the time and space available in the primitive oceans of Earth<ref>{{cite biorxiv|last1=Hoffmann|first1=Geoffrey William|title=A network theory of the origin of life|date=24 December 2016|biorxiv=10.1101/096701}}</ref> Hoffmann suggests that volcanic ash may provide the many random shapes needed in the postulated complex nucleation event. This aspect of the theory can be tested experimentally.<br />
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杰弗里·W.霍夫曼 Geoffrey W.Hoffmann认为,作为生命起源的复杂成核事件涉及多肽和核酸,与地球原始海洋中可用的时间和空间相适应。Hoffmann认为,火山灰可能提供了假设的复杂成核事件中所需要的许多随机形状。这方面的理论可以通过实验来检验。<br />
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=== Gold's deep-hot biosphere ===<br />
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戈德的深热生物圈 <br />
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In the 1970s, [[Thomas Gold]] proposed the theory that life first developed not on the surface of the Earth, but several kilometers below the surface. It is claimed that the discovery of microbial life below the surface of another body in our Solar System would lend significant credence to this theory. Gold also asserted that a trickle of food from a deep, unreachable, source is needed for survival because life arising in a puddle of organic material is likely to consume all of its food and become extinct. Gold's theory is that the flow of such food is due to out-gassing of primordial methane from the Earth's mantle; more conventional explanations of the food supply of deep microbes (away from sedimentary carbon compounds) is that the organisms [[Microbial metabolism#Hydrogen oxidation|subsist on hydrogen]] released by an interaction between water and (reduced) iron compounds in rocks.<br />
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20世纪70年代,托马斯·戈德Thomas Gold提出了生命最初不是在地球表面,而是在地球表面以下几公里处发展起来的理论。据称,如果在我们的太阳系另一个天体表面以下发现微生物生命,将为这一理论提供重要的凭证。Gold还断言,从深不可测的源头获得涓涓细流的食物是生存所需要的,因为在一滩有机物中产生的生命很可能会消耗掉所有的食物而灭绝。Gold的理论是,这种食物的流动是由于地幔中原始甲烷的逸出所致;对深层微生物(远离沉积碳化合物)的食物供应,更传统的解释是,生物靠水和岩石中(还原的)铁化合物之间的相互作用释放的氢气为生。<br />
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=== Radioactive beach hypothesis ===<br />
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放射性海滩假说 <br />
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Zachary Adam claims that tidal processes that occurred during a time when the Moon was much closer may have concentrated grains of [[uranium]] and other radioactive elements at the high-water mark on primordial beaches, where they may have been responsible for generating life's building blocks.<ref>{{cite journal |last=Dartnell |first=Lewis |date=12 January 2008 |title=Did life begin on a radioactive beach? |url=https://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |journal=New Scientist |issue=2638 |page=8 |accessdate=2015-06-26 |url-status=live |archiveurl=https://web.archive.org/web/20150627101858/http://www.newscientist.com/article/mg19726384.000-did-life-begin-on-a-radioactive-beach.html |archivedate=27 June 2015}}</ref> According to computer models,<ref>{{cite journal |last=Adam |first=Zachary |year=2007 |title=Actinides and Life's Origins |journal=Astrobiology |volume=7 |issue=6 |pages=852–872 |bibcode=2007AsBio...7..852A |doi=10.1089/ast.2006.0066|pmid=18163867}}</ref> a deposit of such radioactive materials could show the same [[Natural nuclear fission reactor|self-sustaining nuclear reaction]] as that found in the [[Oklo]] uranium ore seam in [[Gabon]]. Such radioactive beach sand might have provided sufficient energy to generate organic molecules, such as amino acids and sugars from [[acetonitrile]] in water. Radioactive [[monazite]] material also has released soluble phosphate into the regions between sand-grains, making it biologically "accessible." Thus amino acids, sugars, and soluble phosphates might have been produced simultaneously, according to Adam. Radioactive [[actinide]]s, left behind in some concentration by the reaction, might have formed part of [[Organometallic chemistry|organometallic complexes]]. These complexes could have been important early catalysts to living processes.<br />
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扎卡里·亚当 Zachary Adam声称,在月球更接近的时期发生的潮汐过程可能将铀和其他放射性元素的颗粒集中在原始海滩的高水位线上,在那里它们可能负责生成生命的构件。根据计算机模型,这种放射性物质的沉积可能显示出与加蓬奥克洛铀矿缝中发现的相同的自我维持的核反应。这种放射性海滩沙子可能提供了足够的能量来生成有机分子,如水中的乙腈生成氨基酸和糖类。放射性独居石物质还将可溶性磷酸盐释放到沙粒之间的区域,使其成为生物上的 "可利用物质"。据Adam说,因此氨基酸、糖类和可溶性磷酸盐可能是同时产生的。放射性的锕系元素,在反应中留下了一定的浓度,可能已经形成了有机金属复合物的一部分。这些复合物可能是生命过程的重要早期催化剂。<br />
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John Parnell has suggested that such a process could provide part of the "crucible of life" in the early stages of any early wet rocky planet, so long as the planet is large enough to have generated a system of plate tectonics which brings radioactive minerals to the surface. As the early Earth is thought to have had many smaller plates, it might have provided a suitable environment for such processes.<ref>{{cite journal |last=Parnell |first=John |date=December 2004 |title=Mineral Radioactivity in Sands as a Mechanism for Fixation of Organic Carbon on the Early Earth |journal=Origins of Life and Evolution of Biospheres |volume=34 |issue=6 |pages=533–547 |bibcode=2004OLEB...34..533P |doi=10.1023/B:ORIG.0000043132.23966.a1 |pmid=15570707|citeseerx=10.1.1.456.8955 |s2cid=6067448 }}</ref><br />
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约翰·帕内尔 John Parnell认为,在任何早期潮湿的岩石行星的早期阶段,这种过程都可能提供部分 "生命的坩埚",只要该行星足够大,产生了板块构造系统,将放射性矿物带到地表。由于早期地球被认为有许多较小的板块,它可能为这种过程提供了合适的环境。<br />
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== Origin of metabolism: physiology ==<br />
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代谢起源:生理学<br />
Different forms of life with variable origin processes may have appeared quasi-simultaneously in the early [[history of Earth]].<ref>{{cite journal |last=Davies |first=Paul |authorlink=Paul Davies |date=December 2007 |title=Are Aliens Among Us? |url=http://www.zo.utexas.edu/courses/kalthoff/bio301c/readings/07Davies.pdf |journal=Scientific American |volume=297 |issue=6 |pages=62–69 |doi=10.1038/scientificamerican1207-62 |accessdate=2015-07-16 |quote=...if life does emerge readily under terrestrial conditions, then perhaps it formed many times on our home planet. To pursue this possibility, deserts, lakes and other extreme or isolated environments have been searched for evidence of "alien" life-forms—organisms that would differ fundamentally from known organisms because they arose independently. |bibcode=2007SciAm.297f..62D |url-status=live |archiveurl=https://web.archive.org/web/20160304185832/http://www.zo.utexas.edu/courses/kalthoff/bio301c/readings/07Davies.pdf |archivedate=4 March 2016}}</ref> The other forms may be extinct (having left distinctive fossils through their different biochemistry—e.g., [[hypothetical types of biochemistry]]). It has been proposed that:<br />
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在早期的地球历史中,具有不同起源过程的不同生命形式可能准同时出现。其他形式可能已经灭绝(通过其不同的生物化学--如假设的生物化学类型--留下了独特的化石)。有人提出:<br />
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< blockquote >The first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic and other [[dicarboxylic acid]]s. This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of the hotspring acquiring the ability to fix nitrogen. Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids. If biosynthesis recapitulates biopoiesis, then the synthesis of amino acids preceded the synthesis of the purine and pyrimidine bases. Furthermore, the polymerization of the amino acid thioesters into polypeptides preceded the directed polymerization of amino acid esters by polynucleotides.<ref>{{cite journal |last=Hartman |first=Hyman |date=1998 |title=Photosynthesis and the Origin of Life |journal=Origins of Life and Evolution of Biospheres |volume=28 |issue=4–6 |pages=515–521 |bibcode=1998OLEB...28..515H |doi=10.1023/A:1006548904157 |pmid=11536891|s2cid=2464 }}</ref>< /blockquote ><br />
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< blockquote ><br />
最早的生物是自我复制的富铁粘土,它将二氧化碳固定成草酸和其他二羧酸。这种复制粘土及其新陈代谢表型的系统随后进化到富含硫化物的热泉区获得了固氮的能力。最后磷酸盐被纳入进化的系统,使核苷酸和磷脂的合成成为可能。如果说生物合成概括了生物创建,那么氨基酸的合成就先于嘌呤和嘧啶碱基的合成。此外,氨基酸硫酯聚合成多肽,先于多核苷酸定向聚合氨基酸酯。<br />
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Metabolism-like reactions could have occurred naturally in early oceans, before the first organisms evolved.<ref name="Ralser 2014" /><ref name="Metabolism 2014">{{cite press release |last=Senthilingam |first=Meera |date=25 April 2014 |title=Metabolism May Have Started in Early Oceans Before the Origin of Life |url=http://www.eurekalert.org/pub_releases/2014-04/wt-mmh042314.php |publisher=[[Wellcome Trust]] |agency=[[American Association for the Advancement of Science|EurekAlert!]] |accessdate=2015-06-16 |url-status=live |archiveurl=https://web.archive.org/web/20150617102656/http://www.eurekalert.org/pub_releases/2014-04/wt-mmh042314.php |archivedate=17 June 2015}}</ref> Metabolism may predate the origin of life, which may have evolved from the chemical conditions in the earliest oceans. Reconstructions in laboratories show that some of these reactions can produce RNA, and some others resemble two essential reaction cascades of metabolism: [[glycolysis]] and the [[pentose phosphate pathway]], that provide essential precursors for nucleic acids, amino acids and lipids.<ref name="Metabolism 2014" /><br />
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类似新陈代谢的反应可能在早期海洋中自然发生,在第一批生物进化之前。新陈代谢可能早于生命的起源,它可能是由最早的海洋中的化学条件演化而来的。实验室中的重建表明,其中一些反应可以产生RNA,另外一些反应类似于新陈代谢的两个基本反应级联:糖酵解和磷酸戊糖通路,它们为核酸、氨基酸和脂类提供了必要的前体。<br />
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=== Clay hypothesis ===<br />
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粘土假说<br />
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[[Montmorillonite]], an abundant [[clay]], is a catalyst for the polymerization of RNA and for the formation of membranes from lipids.<ref>{{cite press release |last=Perry |first=Caroline |date=7 February 2011 |title=Clay-armored bubbles may have formed first protocells |url=http://www.eurekalert.org/pub_releases/2011-02/hu-cbm020411.php |location=Cambridge, MA |publisher=[[Harvard University]] |agency=EurekAlert! |accessdate=2015-06-20 |url-status=live |archiveurl=https://web.archive.org/web/20150714101638/http://www.eurekalert.org/pub_releases/2011-02/hu-cbm020411.php |archivedate=14 July 2015}}</ref> A model for the origin of life using clay was forwarded by Alexander Cairns-Smith in 1985 and explored as a plausible mechanism by several scientists.<ref>{{harvnb|Dawkins|1996|pp=148–161}}</ref> The clay hypothesis postulates that complex organic molecules arose gradually on pre-existing, non-organic replication surfaces of silicate crystals in solution.<br />
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蒙脱石是一种丰富的粘土,是RNA聚合和脂质形成膜的催化剂。1985年,亚历山大·凯恩斯-史密斯 Alexander Cairns-Smith提出了一个利用粘土进行生命起源的模型,并被一些科学家作为一种似可信的机制进行了探索。粘土假说假定复杂的有机分子是在溶液中的硅酸盐晶体预先存在的非有机重复表面上逐渐产生的。<br />
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At the [[Rensselaer Polytechnic Institute]], James Ferris' studies have also confirmed that montmorillonite clay minerals catalyze the formation of RNA in aqueous solution, by joining nucleotides to form longer chains.<ref>{{cite journal |author1=Wenhua Huang |last2=Ferris |first2=James P. |date=12 July 2006 |title=One-Step, Regioselective Synthesis of up to 50-mers of RNA Oligomers by Montmorillonite Catalysis |journal=Journal of the American Chemical Society |volume=128 |issue=27 |pages=8914–8919 |doi=10.1021/ja061782k |pmid=16819887}}</ref><br />
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在伦斯勒理工学院,詹姆斯·费里斯 James Ferris的研究也证实,蒙脱石粘土矿物在水溶液中催化RNA的形成,通过连接核苷酸形成较长的链。<br />
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In 2007, Bart Kahr from the [[University of Washington]] and colleagues reported their experiments that tested the idea that crystals can act as a source of transferable information, using crystals of [[potassium hydrogen phthalate]]. "Mother" crystals with imperfections were cleaved and used as seeds to grow "daughter" crystals from solution. They then examined the distribution of imperfections in the new crystals and found that the imperfections in the mother crystals were reproduced in the daughters, but the daughter crystals also had many additional imperfections. For gene-like behavior to be observed, the quantity of inheritance of these imperfections should have exceeded that of the mutations in the successive generations, but it did not. Thus Kahr concluded that the crystals "were not faithful enough to store and transfer information from one generation to the next."<ref>{{cite journal |last=Moore |first=Caroline |date=16 July 2007 |title=Crystals as genes? |url=http://www.rsc.org/Publishing/ChemScience/Volume/2007/08/Crystals_as_genes.asp |journal=Highlights in Chemical Science |accessdate=2015-06-21 |url-status=live |archiveurl=https://web.archive.org/web/20150714094855/http://www.rsc.org/Publishing/ChemScience/Volume/2007/08/Crystals_as_genes.asp |archivedate=14 July 2015}}<br />
* {{cite journal |last1=Bullard |first1=Theresa |last2=Freudenthal |first2=John |last3=Avagyan |first3=Serine |last4=Kahr |first4=Bart |display-authors=3 |year=2007 |title=Test of Cairns-Smith's 'crystals-as-genes' hypothesis |journal=[[Faraday Discussions]] |volume=136 |pages=231–245 |bibcode=2007FaDi..136..231B |doi=10.1039/b616612c |pmid=17955812 }}</ref><br />
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2007年,来自华盛顿大学的巴特·卡尔Bart Kahr 及其同事报告了他们的实验,利用邻苯二甲酸氢钾的晶体,检验了晶体可以作为可转移信息的来源的想法。有缺陷的"母"晶体被切割用作种子以从溶液中生长出"子"晶体。然后,他们检查了新晶体中缺陷的分布,发现母晶体中的缺陷在子晶体中重现,但子晶体也有许多额外的缺陷。要想观察到类似基因的行为,这些缺陷的遗传的量应该超过连续几代中的突变的量,但事实并非如此。因此Kahr 得出结论,这些晶体 "不够忠实,无法存储信息并将信息从一代传给下一代”。<br />
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=== Iron–sulfur world ===<br />
铁硫世界<br />
{{Main|Iron–sulfur world theory}}<br />
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In the 1980s, Günter Wächtershäuser, encouraged and supported by [[Karl R. Popper|Karl Popper]],<ref>{{cite journal |last=Yue-Ching Ho |first=Eugene |date=July–September 1990 |title=Evolutionary Epistemology and Sir Karl Popper's Latest Intellectual Interest: A First-Hand Report |url=http://www.tkpw.net/hk-ies/n15/ |journal=Intellectus |volume=15 |pages=1–3 |oclc=26878740 |accessdate=2012-08-13 |url-status=live |archiveurl=https://web.archive.org/web/20120311074143/http://www.tkpw.net/hk-ies/n15/ |archivedate=11 March 2012}}</ref><ref>{{cite news |last=Wade |first=Nicholas |date=22 April 1997 |title=Amateur Shakes Up Ideas on Recipe for Life |url=https://www.nytimes.com/1997/04/22/science/amateur-shakes-up-ideas-on-recipe-for-life.html?src=pm&pagewanted=2&pagewanted=all |newspaper=The New York Times |location=New York |accessdate=2015-06-16 |url-status=live |archiveurl=https://web.archive.org/web/20150617122450/http://www.nytimes.com/1997/04/22/science/amateur-shakes-up-ideas-on-recipe-for-life.html?src=pm&pagewanted=2&pagewanted=all |archivedate=17 June 2015}}</ref><ref>{{cite journal |last=Popper |first=Karl R. |authorlink=Karl Popper |date=29 March 1990 |title=Pyrite and the origin of life |journal=Nature |volume=344 |issue=6265 |page=387 |bibcode=1990Natur.344..387P |doi=10.1038/344387a0 |s2cid=4322774 }}</ref> postulated his iron–sulfur world, a theory of the evolution of pre-biotic chemical pathways as the starting point in the evolution of life. It systematically traces today's biochemistry to primordial reactions which provide alternative pathways to the synthesis of organic building blocks from simple gaseous compounds.<br />
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20世纪80年代,Günter Wächtershäuser在卡尔·波普尔 Karl Popper的鼓励和支持下,提出了他的铁-硫世界,这是一个关于前生物化学途径进化的理论,是生命进化的起点。它系统地将今天的生物化学追溯到原始反应,原始反应提供了从简单的气体化合物合成有机构件的替代途径。<br />
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In contrast to the classical Miller experiments, which depend on external sources of energy (simulated lightning, ultraviolet [[irradiation]]), "Wächtershäuser systems" come with a built-in source of energy: [[sulfide]]s of iron (iron [[pyrite]]) and other minerals. The energy released from [[redox]] reactions of these metal sulfides is available for the synthesis of organic molecules, and such systems may have evolved into autocatalytic sets constituting self-replicating, metabolically active entities predating the life forms known today.<ref name="Ralser 2014" /><ref name="Metabolism 2014" /> Experiments with such sulfides in an aqueous environment at 100&nbsp;°C produced a relatively small yield of [[dipeptide]]s (0.4% to 12.4%) and a smaller yield of [[tripeptide]]s (0.10%) although under the same conditions, dipeptides were quickly broken down.<ref>{{cite journal |last1=Huber |first1=Claudia |last2=Wächtershäuser |first2=Günter |authorlink2=Günter Wächtershäuser |date=31 July 1998 |title=Peptides by Activation of Amino Acids with CO on (Ni,Fe)S Surfaces: Implications for the Origin of Life |journal=Science |volume=281 |issue=5377 |pages=670–672 |bibcode=1998Sci...281..670H |doi=10.1126/science.281.5377.670 |pmid=9685253}}</ref><br />
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与经典的Miller实验依赖外部能量来源(模拟闪电、紫外线照射)不同," Wächtershäuser系统 "自带内置能量来源:铁的硫化物(黄铁矿)和其他矿物。这些金属硫化物的氧化还原反应所释放的能量可用于有机分子的合成,这种系统可能已经演化成自催化组,构成自我复制、代谢活跃的实体,早于今天已知的生命形式。在100℃的水环境中用这种硫化物进行实验,产生了产量相对较小的二肽 (0.4%~12.4%)和更小产量的三肽 (0.10%),尽管在相同的条件下,二肽很快被分解。<br />
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Several models reject the self-replication of a "naked-gene", postulating instead the emergence of a primitive metabolism providing a safe environment for the later emergence of RNA replication. The centrality of the [[Citric acid cycle|Krebs cycle]] (citric acid cycle) to energy production in aerobic organisms, and in drawing in carbon dioxide and hydrogen ions in biosynthesis of complex organic chemicals, suggests that it was one of the first parts of the metabolism to evolve.<ref name="Lane 2009">{{harvnb|Lane|2009}}</ref> Concordantly, [[Geochemistry|geochemist]] Russell has proposed that "the purpose of life is to hydrogenate carbon dioxide" (as part of a "metabolism-first," rather than a "genetics-first," scenario). <ref name="Musser">{{cite web |url=http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |title=How Life Arose on Earth, and How a Singularity Might Bring It Down |last=Musser |first=George |authorlink=George Musser |date=23 September 2011 |work=Observations |type=Blog |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150617211804/http://blogs.scientificamerican.com/observations/how-life-arose-on-earth-and-how-a-singularity-might-bring-it-down/ |archivedate=17 June 2015}}</ref><ref name="Carroll">{{cite web |url=http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |title=Free Energy and the Meaning of Life |last=Carroll |first=Sean |authorlink=Sean M. Carroll |date=10 March 2010 |work=Cosmic Variance |type=Blog |publisher=Discover|accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150714074327/http://blogs.discovermagazine.com/cosmicvariance/2010/03/10/free-energy-and-the-meaning-of-life/ |archivedate=14 July 2015}}</ref> [[Physicist]] [[Jeremy England]] has proposed that life was inevitable from general thermodynamic considerations: < blockquote >... when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.<ref>{{cite journal |last=Wolchover |first=Natalie |date=22 January 2014 |title=A New Physics Theory of Life |url=https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |journal=Quanta Magazine |accessdate=2015-06-17 |url-status=live |archiveurl=https://web.archive.org/web/20150613052830/https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/ |archivedate=13 June 2015}}</ref><ref>{{cite journal |last=England |first=Jeremy L. |authorlink=Jeremy England |date=28 September 2013 |title=Statistical physics of self-replication |url=http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |journal=[[Journal of Chemical Physics]] |volume=139 |issue=12 |page=121923 |arxiv=1209.1179 |bibcode=2013JChPh.139l1923E |doi=10.1063/1.4818538 |pmid=24089735 |accessdate=2015-06-18 |url-status=live |archiveurl=https://web.archive.org/web/20150604131515/http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf |archivedate=4 June 2015|hdl=1721.1/90392 |s2cid=478964 }}</ref>< /blockquote ><br />
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有几个模型否定了"裸基因"的自我复制,而是假设出现了一种原始的新陈代谢,为后来出现的RNA复制提供了安全的环境。克雷布斯循环 Krebs cycle(柠檬酸循环)在需氧生物体内产生能量,以及在复杂有机化学物的生物合成中吸取二氧化碳和氢离子的中心地位,表明它是新陈代谢中最早进化的部分之一。与此相一致的是,地球化学家Russell提出“生命的目的是使二氧化碳氢化”(这是“新陈代谢优先”而不是“基因优先”情形的一部分)。物理学家杰里米·英格兰Jeremy England提出,从一般的热力学考虑,生命是不可避免的:<br />
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...当一组原子受到外部能量源(如太阳或化学燃料)的驱动,并被热浴(如海洋或大气层)所包围时,它往往会逐渐重组自己,以耗散越来越多的能量。这可能意味着,在某些条件下,物质不可避免地获得了与生命相关的关键物理属性。<br />
***讨论:给我们一堆原子,我们会创造出什么呢?可是生命不是为了简单地耗散更多能量,相反,生物具有经济性***<br />
One of the earliest incarnations of this idea was put forward in 1924 with Oparin's notion of primitive self-replicating vesicles which predated the discovery of the structure of DNA. Variants in the 1980s and 1990s include Wächtershäuser's iron–sulfur world theory and models introduced by [[Christian de Duve]] based on the chemistry of [[thioester]]s. More abstract and theoretical arguments for the plausibility of the emergence of metabolism without the presence of genes include a mathematical model introduced by [[Freeman Dyson]] in the early 1980s and [[Stuart Kauffman]]'s notion of collectively autocatalytic sets, discussed later that decade.<br />
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这一思想最早的化身之一是在1924年提出的Oparin的原始自复制囊泡的概念,这比DNA结构的发现还要早。20世纪80年代和90年代的变体包括Wächtershäuser的铁-硫世界理论和克里斯蒂安·德·杜夫 Christian de Duve提出的基于硫酯的化学的模型。对于在没有基因存在的情况下新陈代谢出现的合理性,更加抽象和理论化的论证,包括弗里曼·戴森Freeman Dyson在20世纪80年代初提出的数学模型和斯图亚特·考夫曼Stuart Kauffman的集体自催化集的概念,该观点在该十年晚些时候进行了讨论。<br />
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<br />
Orgel summarized his analysis by stating, < blockquote >There is at present no reason to expect that multistep cycles such as the reductive citric acid cycle will self-organize on the surface of FeS/FeS<sub>2</sub> or some other mineral."<ref>{{cite journal |last=Orgel |first=Leslie E. |date=7 November 2000 |title=Self-organizing biochemical cycles |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=97 |issue=23 |pages=12503–12507 |bibcode=2000PNAS...9712503O |doi=10.1073/pnas.220406697|pmc=18793 |pmid=11058157}}</ref>< /blockquote > It is possible that another type of metabolic pathway was used at the beginning of life. For example, instead of the reductive citric acid cycle, the "open" [[acetyl-CoA]] pathway (another one of the five recognized ways of carbon dioxide fixation in nature today) would be compatible with the idea of self-organization on a metal sulfide surface. The key enzyme of this pathway, [[carbon monoxide dehydrogenase]]/[[CO-methylating acetyl-CoA synthase|acetyl-CoA synthase]], harbors mixed nickel-iron-sulfur clusters in its reaction centers and catalyzes the formation of acetyl-CoA (similar to acetyl-thiol) in a single step. There are increasing concerns, however, that prebiotic [[Thioacetic acid|thiolated]] and [[thioester]] compounds are thermodynamically and kinetically unfavorable to accumulate in presumed prebiotic conditions (i.e. hydrothermal vents).<ref>{{cite journal|last1=Chandru|first1=Kuhan|last2=Gilbert|first2=Alexis|last3=Butch|first3=Christopher|last4=Aono|first4=Masashi|last5=Cleaves|first5=Henderson James II|title=The Abiotic Chemistry of Thiolated Acetate Derivatives and the Origin of Life|journal=Scientific Reports|date=21 July 2016|volume=6|issue=29883|pages=29883|doi=10.1038/srep29883|pmid=27443234|pmc=4956751|bibcode=2016NatSR...629883C}}</ref> It has also been proposed that [[cysteine]] and [[homocysteine]] may have reacted with [[nitrile]]s resulting from the [[Strecker amino acid synthesis|Stecker reaction]], readily forming catalytic thiol-reach poplypeptides.<ref>{{Cite journal|last1=Vallee|first1=Yannick|last2=Shalayel|first2=Ibrahim|last3=Ly|first3=Kieu-Dung|last4=Rao|first4=K. V. Raghavendra|last5=Paëpe|first5=Gael De|last6=Märker|first6=Katharina|last7=Milet|first7=Anne|date=2017-11-08|title=At the very beginning of life on Earth: the thiol-rich peptide (TRP) world hypothesis|url=http://www.ijdb.ehu.es/web/paper/170028yv/at-the-very-beginning-of-life-on-earth-the-thiol-rich-peptide-trp-world-hypothesis|journal=International Journal of Developmental Biology|volume=61|issue=8–9|pages=471–478|doi=10.1387/ijdb.170028yv|pmid=29139533|doi-access=free}}</ref><br />
<br />
Orgel总结他的分析说,<br />
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目前没有理由期望多步循环,如还原性柠檬酸循环会在FeS/ FeS<sub>2</sub>或一些其他矿物的表面自组织。"<br />
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有可能在生命诞生之初就使用了另一种代谢通路。例如,"开放的"乙酰-辅酶A通路(当今公认的自然界中五种二氧化碳固定方式中的另一种)而不是还原性柠檬酸循环,会符合金属硫化物表面的自组织的想法。该通路的关键酶--一氧化碳脱氢酶/乙酰-辅酶A合成酶,在其反应中心藏有镍-铁-硫混合簇,并在一个步骤中催化形成乙酰-辅酶A(类似乙酰-硫醇)。然而,越来越多的人担心,在热力学和动力学上,生命起源以前的硫醇化和硫酯化合物不利于在假定的生命起源以前的条件(如,热液喷口)中积累。然而也有人提出,半胱氨酸和同型半胱氨酸可能已经与施特克反应 Stecker reaction产生的腈类反应,容易形成起催化作用的富硫醇的多肽。*** thiol-reach 应为thiol-rich,poplypeptodes应为polypeptides***<br />
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=== Zinc-world hypothesis ===<br />
锌世界假说<br />
The zinc world (Zn-world) theory of Mulkidjanian<ref name="Mulkidjanian">{{cite journal |last=Mulkidjanian |first=Armen Y. |date=24 August 2009 |title=On the origin of life in the zinc world: 1. Photosynthesizing, porous edifices built of hydrothermally precipitated zinc sulfide as cradles of life on Earth |journal=Biology Direct |volume=4 |page=26 |doi=10.1186/1745-6150-4-26 |pmid=19703272 |pmc=3152778 }}</ref> is an extension of Wächtershäuser's pyrite hypothesis. Wächtershäuser based his theory of the initial chemical processes leading to informational molecules (RNA, peptides) on a regular mesh of electric charges at the surface of pyrite that may have facilitated the primeval [[polymerization]] by attracting reactants and arranging them appropriately relative to each other.<ref>{{cite journal |last=Wächtershäuser |first=Günter |date=December 1988 |title=Before Enzymes and Templates: Theory of Surface Metabolism |journal=[[Microbiology and Molecular Biology Reviews|Microbiological Reviews]] |volume=52 |pages=452–484 |issue=4 |pmc=373159 |pmid=3070320 |doi=10.1128/MMBR.52.4.452-484.1988 }}</ref> The Zn-world theory specifies and differentiates further.<ref name="Mulkidjanian" /><ref>{{cite journal |last1=Mulkidjanian |first1=Armen Y. |last2=Galperin |first2=Michael Y. |date=24 August 2009 |title=On the origin of life in the zinc world. 2. Validation of the hypothesis on the photosynthesizing zinc sulfide edifices as cradles of life on Earth |journal=Biology Direct |volume=4 |page=27 |doi=10.1186/1745-6150-4-27 |pmid=19703275 |pmc=2749021 }}</ref> Hydrothermal fluids rich in H<sub>2</sub>S interacting with cold primordial ocean (or Darwin's "warm little pond") water leads to the precipitation of metal sulfide particles. Oceanic [[Hydrothermal vent|vent systems]] and other hydrothermal systems have a zonal structure reflected in ancient [[Volcanogenic massive sulfide ore deposit|volcanogenic massive sulfide deposits]] (VMS) of hydrothermal origin. They reach many kilometers in diameter and date back to the [[Archean]] Eon. Most abundant are pyrite (FeS<sub>2</sub>), [[chalcopyrite]] (CuFeS<sub>2</sub>), and [[sphalerite]] (ZnS), with additions of [[galena]] (PbS) and [[alabandite]] (MnS). ZnS and MnS have a unique ability to store radiation energy, e.g. from UV light. During the relevant time window of the origins of replicating molecules, the primordial atmospheric pressure was high enough (>100&nbsp;bar, about 100 atmospheres) to precipitate near the Earth's surface, and UV irradiation was 10 to 100 times more intense than now; hence the unique photosynthetic properties mediated by ZnS provided just the right energy conditions to energize the synthesis of informational and metabolic molecules and the selection of photostable nucleobases.<br />
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Mulkidjanian的锌世界(Zn-world)理论是Wächtershäuser的黄铁矿假说的延伸。Wächtershäuser根据他的导致信息分子(RNA、肽)的初始化学过程的理论建立在黄铁矿表面有规律的电荷网状结构上,这种网状结构可能通过吸引反应物并将它们适当地相对排列,促进了原始聚合。"锌世界 "理论进一步明确和区分了富含H<sub>2</sub>S的热流与寒冷的原始海洋(或Darwin的"温暖的小池塘")的水相互作用,导致金属硫化物颗粒的沉淀。大洋喷口系统和其他热液系统的区域结构反映在热液起源的古火山块状硫化物矿床(VMS)中。它们的直径达数千米,可追溯到太古宙。最丰富的是黄铁矿(FeS<sub>2</sub>)、黄铜矿(CuFeS<sub>2</sub>)和闪锌矿(ZnS),另外还有方铅矿(PbS)和硫锰矿(MnS)。ZnS和MnS具有独特的储存辐射能量的能力,例如来自紫外线的能量。在复制分子起源的相关时间窗口内,原始大气压足够高(>100巴,约100个大气压),可以在地球表面附近沉降,紫外线照射强度是现在的10~100倍,因此,ZnS所介导的独特的光合作用特性为供能信息分子和代谢分子的合成以及光稳定核酸碱基的选择提供了正好的能量条件。<br />
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The Zn-world theory has been further filled out with experimental and theoretical evidence for the ionic constitution of the interior of the first proto-cells before archaea, bacteria and [[Origin of eukaryotes|proto-eukaryotes]] evolved. [[Archibald Macallum]] noted the resemblance of body fluids such as blood and lymph to seawater;<ref>{{cite journal |last=Macallum |first=A. B. |authorlink=Archibald Macallum |date=1 April 1926 |title=The Paleochemistry of the body fluids and tissues |journal=[[Physiological Reviews]] |volume=6 |issue=2 |pages=316–357|doi=10.1152/physrev.1926.6.2.316 }}</ref> however, the inorganic composition of all cells differ from that of modern seawater, which led Mulkidjanian and colleagues to reconstruct the "hatcheries" of the first cells combining geochemical analysis with [[Phylogenomics|phylogenomic]] scrutiny of the inorganic ion requirements of universal components of modern cells. The authors conclude that ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K<sup>+</sup>, Zn<sup>2+</sup>, Mn<sup>2+</sup>, and {{chem|[PO|4|]|3−}}. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in what we today call marine settings but is compatible with emissions of vapor-dominated zones of what we today call inland geothermal systems. Under the oxygen depleted, CO<sub>2</sub>-dominated primordial atmosphere, the chemistry of water condensates and exhalations near geothermal fields would resemble the internal milieu of modern cells. Therefore, the precellular stages of evolution may have taken place in shallow "Darwin ponds" lined with porous [[silicate minerals]] mixed with metal sulfides and enriched in K<sup>+</sup>, Zn<sup>2+</sup>, and phosphorus compounds.<ref>{{cite journal |last1=Mulkidjanian |first1=Armen Y. |last2=Bychkov |first2=Andrew Yu. |last3=Dibrova |first3=Daria V. |last4=Galperin |first4=Michael Y. |last5=Koonin |first5=Eugene V. |display-authors=3 |date=3 April 2012 |title=Origin of first cells at terrestrial, anoxic geothermal fields |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=109 |issue=14 |pages=E821–E830 |bibcode=2012PNAS..109E.821M |doi=10.1073/pnas.1117774109 |pmc=3325685 |pmid=22331915}}</ref><ref>For a deeper integrative version of this hypothesis, see in particular {{harvnb|Lankenau|2011|pp=225–286}}, interconnecting the "Two RNA worlds" concept and other detailed aspects; and {{cite journal |last1=Davidovich |first1=Chen |last2=Belousoff |first2=Matthew |last3=Bashan |first3=Anat |last4=Yonath |first4=Ada |authorlink4=Ada Yonath |date=September 2009 |title=The evolving ribosome: from non-coded peptide bond formation to sophisticated translation machinery |journal=Research in Microbiology |volume=160 |issue=7 |pages=487–492 |doi=10.1016/j.resmic.2009.07.004 |pmid=19619641}}</ref><br />
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锌世界理论已经被在古细菌、细菌和原真核生物演化之前的第一批原细胞内部的离子构成的实验和理论上的证据进一步充实了。阿奇博尔德·麦卡勒姆 Archibald Macallum注意到血液和淋巴等体液与海水的相似性;然而,所有细胞的无机成分与现代海水的无机成分不同,这使得Mulkidjanian及其同事结合地球化学分析和系统发育组学审查现代细胞普遍成分的无机离子需求,重建了第一批细胞的"孵化器"。作者得出的结论是,普遍存在的,并根据推断,原始的蛋白质和功能系统显示出对K<sup>+</sup>, Zn<sup>2+</sup>, Mn<sup>2+</sup>和[PO4]3−的亲和性和功能需求。<br />
地球化学重建表明,有利于细胞起源的离子成分不可能存在于我们今天所说的海洋环境中,而是与我们今天所说的内陆地热系统的蒸汽主导区的排放相符合。在缺氧的、以二氧化碳为主的原始大气下,地热场附近的水凝结物和蒸发物的化学性质会类似于现代细胞的内环境。因此,细胞前的进化阶段可能发生在浅层的"达尔文池塘"中,池塘内衬与金属硫化物混合的多孔硅酸盐矿物,富含K<sup>+</sup>, Zn<sup>2+</sup>和磷化合物。<br />
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==Other abiogenesis scenarios==<br />
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其他非生物起源的情景<br />
We define a scenario as a set of related concepts pertinent to the origin of life that is or has been investigated. The concepts related to the Iron-Sulfur world can be considered as a scenario. We consider some other scenarios that may partially overlap with scenarios discussed above or with each other.<br />
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我们将情景定义为一组正在或已经被研究过的生命起源相关的一组相关概念。可以将与铁硫世界有关的概念视为一种情景。我们考虑一些其他情景,这些情景可能与上面讨论的方案或彼此部分重叠。<br />
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===Chemical pathways described by computer===<br />
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计算机描述的化学通路<br />
In September 2020, chemists described, for the first time, possible chemical pathways from nonliving prebiotic chemicals to [[Biochemistry|complex biochemicals]] that could give rise to [[Earliest known life forms|living organisms]], based on a new computer program named ALLCHEMY.<ref name="SA-20200103">{{cite news |last=Starr |first=Michelle |title=A New Chemical 'Tree of The Origins of Life' Reveals Our Possible Molecular Evolution |url=https://www.sciencealert.com/a-new-chemical-tree-of-the-origins-of-life-reveals-our-possible-chemical-evolution |date=3 October 2020 |work=[[ScienceAlert]] |accessdate=3 October 2020 }}</ref><ref name="SCI-20200925">{{cite journal |author=Wolos, Agnieszka |display-authors=et al. |title=Synthetic connectivity, emergence, and self-regeneration in the network of prebiotic chemistry |url=https://science.sciencemag.org/content/369/6511/eaaw1955 |date=25 September 2020 |journal=[[Science (journal)|Science]] |volume=369 |issue=6511 |doi=10.1126/science.aaw1955 |doi-broken-date=10 October 2020 |pmid=32973002 |accessdate=3 October 2020 }}</ref><br />
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2020年9月,化学家们首次基于一个名为“ALLCHEMY”的新计算机程序,描述了从无生命生命起源以前的化学物质到复杂的生物化学物质可能产生生命体的化学通路。<br />
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===The hypercycle===<br />
超循环理论<br />
In the early 1970s, Manfred Eigen and [[Peter Schuster]] examined the transient stages between the molecular chaos and a self-replicating [[Hypercycle (chemistry)|hypercycle]] in a prebiotic soup.<ref>{{harvnb|Eigen|Schuster|1979}}</ref> In a hypercycle, the [[information]] storing system (possibly RNA) produces an [[enzyme]], which catalyzes the formation of another information system, in sequence until the product of the last aids in the formation of the first information system. Mathematically treated, hypercycles could create [[Quasispecies model|quasispecies]], which through natural selection entered into a form of Darwinian evolution. A boost to hypercycle theory was the discovery of [[ribozyme]]s capable of catalyzing their own chemical reactions. The hypercycle theory requires the existence of complex biochemicals, such as nucleotides, which do not form under the conditions proposed by the Miller–Urey experiment.<br />
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20世纪70年代初,曼弗雷德·艾根 Manfred Eigen和彼得·舒斯特 Peter Schuster研究了分子混沌和前生物汤中的自复制超循环之间的瞬时阶段。在超循环中,信息存储系统(可能是RNA)产生一种酶,这种酶依次催化另一个信息系统的形成,直到最后一个信息系统的产物帮助第一个信息系统的形成。经过数学处理,超循环可以创造准物种,通过自然选择进入一种达尔文的进化论的形式。对超循环理论的推动是发现了能够催化他们自身的化学反应的核酶。超循环理论要求存在如核苷酸等复杂的生化物质,而在Miller–Urey实验提出的条件下,核苷酸是不会形成的。<br />
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===Organic pigments in dissipative structures===<br />
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耗散结构中的有机颜料<br />
In his "Thermodynamic Dissipation Theory of the Origin and Evolution of Life",<ref>{{cite journal |bibcode=2011ESD.....2...37M |title= Thermodynamic Origin of Life |journal=Earth System Dynamics |volume=0907 |issue=2011 |pages=37–51 |last1=Michaelian |first1=K |year=2009 |arxiv=0907.0042 |doi=10.5194/esd-2-37-2011 |s2cid= 14574109 }}</ref><ref name="Michaelian, K. 2011">{{cite journal |doi=10.5194/esd-2-37-2011 |title= Thermodynamic dissipation theory for the origin of life |journal=Earth System Dynamics |volume=2 |issue=1 |pages=37–51 |year=2011 |last1= Michaelian |first1=K |bibcode=2011ESD.....2...37M |arxiv=0907.0042 |s2cid= 14574109 }}</ref><ref name="Michaelian, K. 2017">{{cite journal |doi= 10.1016/j.heliyon.2017.e00424 |pmid=29062973 |pmc=5647473 |title=Microscopic dissipative structuring and proliferation at the origin of life |journal=Heliyon |volume=3 |issue=10 |pages=e00424 |year=2017 |last1=Michaelian |first1=Karo }}</ref> Karo Michaelian has taken the insight of Boltzmann and the work of Prigogine to its ultimate consequences regarding the origin of life. This theory postulates that the hallmark of the origin and evolution of life is the microscopic dissipative structuring of [[Biological pigment|organic pigments]] and their proliferation over the entire Earth surface.<ref name="Michaelian, K. 2017" /> Present day life augments the entropy production of Earth in its solar environment by dissipating [[ultraviolet]] and [[Visible spectrum|visible]] [[photon]]s into heat through organic pigments in water. This heat then catalyzes a host of secondary dissipative processes such as the [[water cycle]], [[Ocean current|ocean]] and [[wind]] currents, [[Tropical cyclone|hurricanes]], etc.<ref name="Michaelian, K. 2011"/><ref name="HESS Opinions 'Biological catalysis"/> Michaelian argues that if the thermodynamic function of life today is to produce entropy through photon dissipation in organic pigments, then this probably was its function at its very beginnings. It turns out that both [[RNA]] and [[DNA]] when in water solution are very strong absorbers and extremely rapid dissipaters of ultraviolet light within the 230–290&nbsp;nm wavelength (UV-C) region, which is a part of the Sun's spectrum that could have penetrated the prebiotic [[Atmosphere of Earth|atmosphere]].<ref>Sagan, C. (1973) Ultraviolet Selection Pressure on the Earliest Organisms, J. Theor. Biol., 39, 195–200.</ref> In fact, not only RNA and DNA, but many fundamental molecules of life (those common to all three [[Domain (biology)|domains]] of life) are also pigments that absorb in the UV-C, and many of these also have a chemical affinity to RNA and DNA.<ref>{{cite journal |doi=10.5194/bg-12-4913-2015 |title=Fundamental molecules of life are pigments which arose and co-evolved as a response to the thermodynamic imperative of dissipating the prevailing solar spectrum |journal=Biogeosciences |volume=12 |issue=16 |pages=4913–4937 |year=2015 |last1=Michaelian |first1=K |last2=Simeonov |first2=A |bibcode=2015BGeo...12.4913M |arxiv=1405.4059v2 }}</ref> [[Nucleic acid]]s may thus have acted as acceptor molecules to the UV-C photon [[Excited state|excited]] antenna pigment donor molecules by providing an [[Conical intersection|ultrafast channel]] for dissipation. Michaelian has shown using the formalism of non-linear irreversible thermodynamics that there would have existed during the [[Archean]] a thermodynamic imperative to the abiogenic UV-C [[Photochemistry|photochemical]] synthesis and proliferation of these pigments over the entire Earth surface if they acted as [[Catalysis|catalysts]] to augment the dissipation of the solar photons.<ref>{{cite journal |doi=10.1088/1742-6596/475/1/012010 |title=A non-linear irreversible thermodynamic perspective on organic pigment proliferation and biological evolution |journal= Journal of Physics: Conference Series |volume=475 |issue=1 |pages=012010 |year=2013 |last1=Michaelian |first1=K |bibcode= 2013JPhCS.475a2010M |arxiv=1307.5924 |s2cid=118564759 }}</ref> By the end of the Archean, with life-induced [[ozone]] dissipating UV-C light in the Earth's upper atmosphere, it would have become ever more improbable for a completely new life to emerge that did not rely on the complex metabolic pathways already existing since now the free energy in the photons arriving at Earth's surface would have been insufficient for direct breaking and remaking of [[covalent bond]]s. It has been suggested, however, that such changes in the surface flux of ultraviolet radiation due to geophysical events affecting the atmosphere could have been what promoted the development of complexity in life based on existing metabolic pathways, for example during the [[Cambrian explosion]]<ref>{{cite journal | last1 = Doglioni | first1 = C. | last2 = Pignatti | first2 = J. | last3 = Coleman | first3 = M. | year = 2016 | title = Why did life develop on the surface of the Earth in the Cambrian? | journal = Geoscience Frontiers | volume = 7 | issue = 6| pages = 865–873 | doi=10.1016/j.gsf.2016.02.001| url = https://iris.uniroma1.it/bitstream/11573/925124/1/Doglioni_Why_2016.pdf }}</ref><br />
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在他的 "生命起源和进化的热力学耗散理论 "中,卡洛·米迦勒安 Karo Michaelian将Boltzmann的洞见和Prigogine的工作用于关于生命起源的最终结果。该理论假设生命起源和进化的标志是有机颜料的微观耗散结构及其在整个地球表面的扩散。现今的生命通过将紫外线和可见光子通过水中的有机颜料耗散成热能,增强了地球在太阳环境中的熵产生。这种热量就会催化大量的二次耗散过程,如水循环、洋流和风流、飓风等。Michaelian认为,如果说今天生命的热力学功能是通过有机颜料中光子耗散产生熵,那么这可能是它在一开始就具有的功能。事实证明,RNA和DNA在水溶液中时,都是230-290nm波长(UV-C)区域内紫外线的极强吸收者和极快耗散者,这是太阳光谱中可能穿透生命起源以前大气层的一部分。事实上,不仅是RNA和DNA,许多生命的基本分子(生命所有三个域共同的分子)也是在UV-C中吸收的色素,其中许多也与RNA和DNA有化学亲和力。因此,核酸可能通过提供一个超快的耗散通道,充当了UV-C光子激发的天线色素供体分子的受体分子。Michaelian用非线性不可逆热力学的形式体系表明,在太古宙,如果这些色素作为催化剂来增强太阳光子的耗散,那么这些色素的生命起源前UV-C光化学合成和扩散在整个地球表面就会存在一种热力学上的必然性。到了太古宙末期,随着生命诱导的臭氧使地球上层大气中的UV-C光耗散,要想出现一种不依赖已有的复杂代谢通路的全新生命将变得越来越不可能,因为现在到达地球表面的光子中的自由能已经不足以直接破坏和重造共价键。然而,有人认为,由于影响大气层的地球物理事件造成的紫外线辐射的地表通量的这种变化,可能是在现有代谢通路的基础上促进生命复杂性发展的原因,例如在寒武纪生命大爆发期间。<br />
***讨论:应该做一张图,标注这些理论试图解释的生命起源的时间段,以及瞄准的方面,看看理论之间是否自洽,如何互相联系,以及各自缺乏哪些方面的思考***<br />
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Some of the most difficult problems concerning the origin of life, such as enzyme-less [[DNA replication|replication]] of RNA and DNA,<ref>{{cite journal |last1=Michaelian |first1=Karo |last2=Santillán |first2=Norberto |title=UVC photon-induced denaturing of DNA: A possible dissipative route to Archean enzyme-less replication |journal=Heliyon |date=June 2019 |volume=5 |issue=6 |page=e01902 |doi=10.1016/j.heliyon.2019.e01902|pmid=31249892 |pmc=6584779 }}</ref> [[homochirality]] of the fundamental molecules,<ref>{{cite journal |last1=Michaelian |first1=Karo |title=Homochirality through Photon-Induced Denaturing of RNA/DNA at the Origin of Life |journal=Life |date=June 2018 |volume=8 |issue=2 |page=21 |doi=10.3390/life8020021 |pmid=29882802 |pmc=6027432 }}</ref> and the origin of [[Genetic code|information encoding]] in RNA and DNA, also find an explanation within the same dissipative thermodynamic framework by considering the probable existence of a relation between primordial replication and UV-C photon dissipation. Michaelian suggests that it is erroneous to expect to describe the emergence, proliferation, or even evolution, of life without overwhelming reference to entropy production through the dissipation of a generalized thermodynamic potential, in particular, the prevailing solar photon flux.<br />
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关于生命起源的一些最困难的问题,如RNA和DNA的无酶复制,基本分子的同手型,以及RNA和DNA中信息编码的起源,也可以通过考虑原始复制和UV-C光子耗散之间可能存在的关系,在同一耗散热力学框架内找到解释。Michaelian认为,如果期望描述生命的涌现、增殖甚至进化,而不大量提及通过耗散广义热力学势能,特别是主流太阳光子通量产生的熵,那是错误的。<br />
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===Protein amyloid===<br />
淀粉样蛋白<br />
A new origin-of-life theory based on self-replicating beta-sheet structures has been put forward by Maury in 2009.<ref>{{cite journal | last1 = Maury | first1 = CP | year = 2009 | title = Self-proagating beta-sheet polypeptide structures as prebiotic informational entities:The amyloid world | journal = Origins of Life and Evolution of Biospheres | volume = 39 | issue = 2| pages = 141–150 | doi = 10.1007/s11084-009-9165-6 | pmid = 19301141 | s2cid = 20073536 }}</ref><ref>{{cite journal | last1 = Maury | first1 = CP | year = 2015 | title = Origin of Life.Primordial genetics: Information transfer in a pre-RNA world based on self-replicating beta-sheet amyloid conformers | journal = Journal of Theoretical Biology | volume = 382 | pages = 292–297 | doi = 10.1016/j.jtbi.2015.07.008 | pmid = 26196585 | doi-access = free }}</ref> The theory suggest that self-replicating and self-assembling catalytic [[amyloid]]s were the first informational polymers in a primitive pre-RNA world. The main arguments for the ''amyloid hypothesis'' is based on the structural stability, autocatalytic and catalytic properties, and evolvability of beta-sheet based informational systems. Such systems are also error correcting<ref>{{cite journal | last1 = Nanda | first1 = J | last2 = Rubinov | first2 = B | last3 = Ivnitski | first3 = D | last4 = Mukherjee | first4 = R | last5 = Shtelman | first5 = E | last6 = Motro | first6 = Y | last7 = Miller | first7 = Y | last8 = Wagner | first8 = N | last9 = Cohen-Luria | first9 = R | last10 = Ashkenasy | first10 = G | year = 2017 | title = Emergence of native peptide seuqences in prebiotic replication networks | journal = Nature Communications | volume = 8 | issue = 1| page = 343 | doi = 10.1038/s41467-017-00463-1 | pmid = 28874657 | pmc = 5585222 | bibcode = 2017NatCo...8..434N }}</ref> and [[chiroselective]].<ref>{{cite journal | last1 = Rout | first1 = SK | last2 = Friedmann | first2 = MP | last3 = Riek | first3 = R | last4 = Greenwald | first4 = J | year = 2018 | title = A prebiotic templated-directed synthesis based on amyloids | journal = Nature Communications | volume = 9 | issue = 1| pages = 234–242 | doi = 10.1038/s41467-017-02742-3 | pmid = 29339755 | pmc = 5770463 }}</ref><br />
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<!--Possible subsections to split off after enough content is added: evidence relating to the RNA world and the evolution of protein synthesis--><br />
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2009年莫里 Maury提出了一种基于自复制β-片层结构的新的生命起源理论。该理论认为,自复制和自组装催化的淀粉样蛋白是原始的前RNA世界中的第一个信息聚合物。“淀粉样蛋白假说”的主要论据是基于β-片层为基础的信息系统的结构稳定性、自催化和催化性以及可进化性。这种系统还具有纠错性*英文缺失***和手性选择性。***<br />
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=== Fluctuating salinity: dilute and dry-down ===<br />
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变化的盐度:稀释和干涸。 <br />
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Theories of abiogenesis seldom address the caveat raised by Harold Blum:<ref>Blum, H.F. (1957). On the origin of self-replicating systems. In Rhythmic and Synthetic Processes in Growth, ed. Rudnick, D., pp. 155–170. Princeton University Press, Princeton, NJ.</ref> if the key informational elements of life – proto-nucleic acid chains – spontaneously form duplex structures, then there is no way to dissociate them. < blockquote >Somewhere in this cycle work must be done, which means that free energy must be expended. If the parts assemble themselves on a template spontaneously, work has to be done to take the replica off; or, if the replica comes off the template of its own accord, work must be done to put the parts on in the first place.< /blockquote ><br />
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非生物起源理论很少涉及哈罗德·布卢姆Harold Blum提出的警告:如果生命的关键信息元素——原核酸链——自发形成双螺旋结构,那么就没有办法将它们解离。<br />
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在这个循环的某个地方,必须做功,这意味着自由能必须被消耗。如果零件自发地在模板上组装起来,就必须做功才能把复制品取下来;或者,如果复制品自动从模板上脱落,首先一定要做功把这些零件装上。<br />
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The Oparin–Haldane conjecture addresses the formation, but not the dissociation, of nucleic acid polymers and duplexes. However, nucleic acids are unusual because, in the absence of counterions (low salt) to neutralize the high charges on opposing phosphate groups, the nucleic acid duplex dissociates into single chains.<ref name="ReferenceB">{{Cite journal |doi = 10.1016/j.icarus.2003.10.018|title = Fast tidal cycling and the origin of life|year = 2004|last1 = Lathe|first1 = Richard|journal = Icarus|volume = 168|issue = 1|pages = 18–22|bibcode = 2004Icar..168...18L}}</ref> Early tides, driven by a close moon, could have generated rapid cycles of dilution (high tide, low salt) and concentration (dry-down at low tide, high salt) that exclusively promoted the replication of nucleic acids<ref name="ReferenceB"/> through a process dubbed tidal chain reaction (TCR).<ref>{{Cite journal |doi = 10.1017/S1473550405002314|title = Tidal chain reaction and the origin of replicating biopolymers|year = 2005|last1 = Lathe|first1 = Richard|journal = International Journal of Astrobiology|volume = 4|issue = 1|pages = 19–31|bibcode = 2005IJAsB...4...19L}}</ref> This theory has been criticized on the grounds that early tides may not have been so rapid,<ref>{{Cite journal |doi = 10.1016/j.icarus.2005.04.022|title = Comment on the paper "Fast tidal cycling and the origin of life" by Richard Lathe|year = 2006|last1 = Varga|first1 = P.|last2 = Rybicki|first2 = K.|last3 = Denis|first3 = C.|journal = Icarus|volume = 180|issue = 1|pages = 274–276|bibcode = 2006Icar..180..274V}}</ref> although regression from current values requires an Earth–Moon juxtaposition at around two Ga, for which there is no evidence, and early tides may have been approximately every seven hours.<ref>{{Cite journal |doi = 10.1016/j.icarus.2005.08.019|title = Early tides: Response to Varga et al|year = 2006|last1 = Lathe|first1 = R.|journal = Icarus|volume = 180|issue = 1|pages = 277–280|bibcode = 2006Icar..180..277L}}</ref> Another critique is that only 2–3% of the Earth's crust may have been exposed above the sea until late in terrestrial evolution.<ref>{{Cite journal | doi=10.1016/j.epsl.2008.08.029| title=A case for late-Archaean continental emergence from thermal evolution models and hypsometry| year=2008| last1=Flament| first1=Nicolas| last2=Coltice| first2=Nicolas| last3=Rey| first3=Patrice F.| journal=Earth and Planetary Science Letters| volume=275| issue=3–4| pages=326–336| bibcode=2008E&PSL.275..326F}}</ref><br />
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Oparin-Haldane猜想解决的是核酸聚合物和双螺旋的形成,而不是解离。然而,核酸是不寻常的,因为在没有反离子(低盐)中和对立的磷酸基团上的高电荷时,核酸双螺旋会解离成单链。早期的潮汐,在近月的驱动下,可能产生了快速的稀释(高潮、低盐)和浓缩(低潮、高盐时干涸)循环,通过被称为潮汐链式反应(TCR)的过程,专门促进核酸的复制。 这一理论受到了批评,理由是早期的潮汐可能并不那么快,英文翻译不确定***尽管从目前数值的回归需要在二十亿年左右的地月毗邻***,但没有证据表明这一点,而且早期的潮汐可能大约是每7个小时一次。另一种批评认为,直到陆地演化的晚期,只有2-3%的地壳可能暴露在海面上。<br />
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The TCR (tidal chain reaction) theory has mechanistic advantages over thermal association/dissociation at deep-sea vents because TCR requires that chain assembly (template-driven polymerization) takes place during the dry-down phase, when precursors are most concentrated, whereas thermal cycling needs polymerization to take place during the cold phase, when the rate of chain assembly is lowest and precursors are likely to be more dilute.<br />
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在深海喷口, TCR (潮汐链式反应)理论与热联合/解离相比,在力学上具有优势,因为潮汐链式反应要求链的组装(模板驱动的聚合)发生在干涸阶段,即前体最集中的时候,而热循环则需要聚合发生在冷阶段,即链的组装速度最低,前体可能更稀薄的时候。<br />
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=== A first protein that condenses substrates during thermal cycling: thermosynthesis===<br />
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第一个在热循环过程中凝结底物的蛋白质:热合成作用<br />
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[[File:ConvectionCells.svg|thumb|upright=1.25|Convection cells in fluid placed in a gravity field are selforganizing and enable thermal cycling of the suspended contents in the fluid such as protocells containing protoenzymes that work on thermal cycling.]]<br />
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放置在重力场中的流体中的对流小室是自组织的,能够使流体中的悬浮物进行热循环,例如含有在热循环中起作用的原酶的原始细胞。<br />
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'''Emergence of chemiosmotic machinery''' Today's bioenergetic process of [[fermentation]] is carried out by either the aforementioned citric acid cycle or the Acetyl-CoA pathway, both of which have been connected to the primordial Iron–sulfur world.<br />
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化学渗透机制的出现<br />
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今天发酵的生物能过程是由上述柠檬酸循环或乙酰-辅酶A通路进行的,这两种通路都与原始的铁-硫世界有关。<br />
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In a different approach, the thermosynthesis hypothesis considers the bioenergetic process of [[chemiosmosis]], which plays an essential role in [[cellular respiration]] and photosynthesis, more basal than fermentation: the [[ATP synthase]] enzyme, which sustains chemiosmosis, is proposed as the currently extant enzyme most closely related to the first metabolic process.<ref>{{cite journal |last=Muller |first=Anthonie W. J. |date=7 August 1985 |pages=429–453 |title=Thermosynthesis by biomembranes: Energy gain from cyclic temperature changes |journal=[[Journal of Theoretical Biology]] |volume=115 |issue=3 |doi=10.1016/S0022-5193(85)80202-2 |pmid=3162066}}</ref><ref>{{cite journal |last=Muller |first=Anthonie W. J. |year=1995 |title=Were the first organisms heat engines? A new model for biogenesis and the early evolution of biological energy conversion |journal=Progress in Biophysics and Molecular Biology |volume=63 |issue=2 |pages=193–231 |doi=10.1016/0079-6107(95)00004-7 |pmid=7542789}}</ref><br />
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热合成假说则用不同的方法,认为在细胞呼吸和光合作用中起着必要作用的化学渗透的生物能量过程比发酵更基础:提出维持化学渗透的ATP合成酶是目前现存的与第一个代谢过程关系最密切的酶。<br />
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First life needed an energy source to bring about the condensation reaction that yielded the peptide bonds of proteins and the [[phosphodiester bond]]s of RNA. In a generalization and thermal variation of the [[ATP synthase#Binding model|binding change mechanism]] of today's ATP synthase, the "first protein" would have bound substrates (peptides, phosphate, nucleosides, RNA 'monomers') and condensed them to a reaction product that remained bound until it was released after a temperature change by a thermal unfolding. The primordial '''first protein''' would therefore have strongly resembled the beta subunits of the [[ATP synthase alpha/beta subunits]] of today's F<sub>1</sub> moiety in the F<sub>o</sub>F<sub>1</sub> [[ATP synthase]]. Note however that today's enzymes function during isothermal conditions, whereas the hypothetical first protein worked on and during thermal cycling.<br />
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第一个生命需要一个能量源来实现缩合反应,产生蛋白质的肽键和RNA的磷酸二酯键。在今天ATP合成酶的结合变化机制的概括和热变化中,"第一种蛋白质"应该是结合了底物(肽、磷酸盐、核苷、RNA"单体"),并将它们缩合成一种反应产物,这种产物一直保持结合,直到温度变化后通过热诱导去折叠被释放。因此,原始的“第一种蛋白质”应该会与今天的F<sub>o</sub>F<sub>1</sub> ATP合成酶中的F<sub>1</sub>部分的ATP合成酶的α/β亚基的β亚基非常相似。但请注意,今天的酶是在等温条件下发挥功能的,而假设的第一种蛋白质则是在热循环中工作的。<br />
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The energy source under the thermosynthesis hypothesis was thermal cycling, the result of suspension of protocells in a [[convection]] current, as is plausible in a volcanic hot spring; the convection accounts for the self-organization and [[Dissipative system|dissipative structure]] required in any origin of life model. The still ubiquitous role of thermal cycling in germination and cell division is considered a relic of primordial thermosynthesis.<br />
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热合成假说下的能量来源是热循环,是原细胞悬浮在对流中的结果,就像在火山热泉中一样是似可信的;对流说明了任何生命起源模型中所需要的自组织和耗散结构。热循环在发芽和细胞分裂中仍然无处不在的作用被认为是原始热合成的遗迹。<br />
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By [[Phosphorylation|phosphorylating]] cell membrane lipids, this '''first protein''' gave a selective advantage to the lipid protocell that contained the protein. This protein also synthesized a library of many proteins, of which only a minute fraction had thermosynthesis capabilities. As proposed by Dyson,<ref name="Dyson 1999" /> it propagated functionally: it made daughters with similar capabilities, but it did not copy itself. Functioning daughters consisted of different amino acid sequences.<br />
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通过对细胞膜脂质的磷酸化,这“第一种蛋白质”给含有该蛋白质的脂质原细胞带来了选择性优势。这种蛋白质还合成了一个由许多种蛋白质组成的库,其中只有一小部分具有热合成能力。正如Dyson提出的那样,它在功能上进行了传播:它制造了具有类似能力的子代,但它没有复制自己。有功能的子代由不同的氨基酸序列组成。<br />
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Whereas the iron–sulfur world identifies a circular pathway as the most simple, the thermosynthesis hypothesis does not even invoke a pathway: [[ATP synthase#Binding model|ATP synthase's binding change mechanism]] resembles a physical adsorption process that yields free energy,<ref>{{cite journal |last1=Muller |first1=Anthonie W. J. |last2=Schulze-Makuch |first2=Dirk |authorlink2=Dirk Schulze-Makuch |date=1 April 2006 |title=Sorption heat engines: Simple inanimate negative entropy generators |journal=[[Physica (journal)#Physica A: Statistical Mechanics and its Applications|Physica A: Statistical Mechanics and its Applications]] |volume=362 |issue=2 |pages=369–381 |arxiv=physics/0507173 |bibcode=2006PhyA..362..369M |doi=10.1016/j.physa.2005.12.003 |s2cid=96186464 }}</ref> rather than a regular enzyme's mechanism, which decreases the free energy.<br />
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然而铁-硫世界确定的循环通路是最简单的,热合成假说甚至没有调用通路。ATP合成酶的结合变化机制类似于产生自由能的物理吸附过程,而不是减少自由能的普通的酶的机制,。<br />
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The described first protein may be simple in the sense that is requires only a short sequence of conserved amino acid residues, a sequent sufficient for the appropriate catalytic cleft. In contrast, it has been claimed that the emergence of cyclic systems of protein catalysts such as required by fermentation is implausible because of the length of many required sequences.<ref>{{harvnb|Orgel|1987|pp=9–16}}</ref><br />
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在只需要一条保守的氨基酸残基的短序列的意义上,所述的第一种蛋白质可能是简单的,这条序列足以满足适当的催化裂隙。相反,有人声称,由于许多所需序列的长度,出现诸如发酵所需的蛋白质催化剂的循环系统是不可信的。<br />
讨论***可见,其实不同假说只是从不同角度考虑“生命的本质是xxx”这一问题***<br />
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=== Pre-RNA world: The ribose issue and its bypass ===<br />
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前RNA世界:核糖问题和及其旁路<br />
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It is possible that a different type of nucleic acid, such as peptide nucleic acid, threose nucleic acid or glycol nucleic acid, was the first to emerge as a self-reproducing molecule, only later replaced by RNA. Larralde et al., say that < blockquote >the generally accepted prebiotic synthesis of ribose, the formose reaction, yields numerous sugars without any selectivity.< /blockquote > and they conclude that their < blockquote >results suggest that the backbone of the first genetic material could not have contained ribose or other sugars because of their instability.< /blockquote > The ester linkage of ribose and phosphoric acid in RNA is known to be prone to hydrolysis.<br />
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有可能一种不同类型的核酸,如肽核酸、苏糖核酸或乙二醇核酸,最先以自再生分子的形式出现,只是后来被RNA所取代。拉腊尔德 Larralde 等人说,<br />
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普遍接受的生物前核糖的合成,即甲醛聚糖反应,产生了许多没有任何选择性的糖类。<br />
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他们得出结论,他们的<br />
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结果表明,第一种遗传物质的主干不可能含有核糖或其他糖类,因为它们不稳定。<br />
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已知RNA中核糖和磷酸的酯连接容易发生水解。<br />
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Pyrimidine ribonucleosides and their respective nucleotides have been prebiotically synthesized by a sequence of reactions which by-pass the free sugars, and are assembled in a stepwise fashion by using nitrogenous or oxygenous chemistries. Sutherland has demonstrated high yielding routes to cytidine and uridine ribonucleotides built from small 2 and 3 carbon fragments such as glycolaldehyde, glyceraldehyde or glyceraldehyde-3-phosphate, cyanamide and cyanoacetylene. One of the steps in this sequence allows the isolation of enantiopure ribose aminooxazoline if the enantiomeric excess of glyceraldehyde is 60% or greater. This can be viewed as a prebiotic purification step, where the said compound spontaneously crystallized out from a mixture of the other pentose aminooxazolines. Ribose aminooxazoline can then react with cyanoacetylene in a mild and highly efficient manner to give the alpha cytidine ribonucleotide. Photoanomerization with UV light allows for inversion about the 1' anomeric centre to give the correct beta stereochemistry. In 2009 they showed that the same simple building blocks allow access, via phosphate controlled nucleobase elaboration, to 2',3'-cyclic pyrimidine nucleotides directly, which are known to be able to polymerize into RNA. This paper also highlights the possibility for the photo-sanitization of the pyrimidine-2',3'-cyclic phosphates.<br />
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嘧啶核糖核苷及其各自的核苷酸已经通过一连串的反应,绕过游离的糖类,利用含氮或含氧的化学反应,一步步地组装起来,进行了生物起源以前的合成。Sutherland已经证明了由小的2和3个碳片段如羟乙醛、甘油醛或甘油醛-3-磷酸、氰胺和氰基乙炔构建胞嘧啶和尿嘧啶核糖核苷酸的高产路线。该序列中的一个步骤允许分离出对映纯的核糖氨基噁唑啉,如果甘油醛的对映体过量为大于或等于60%。这可以看作是一个生物起源以前的纯化步骤,所述化合物自发地从其他戊糖氨基恶唑啉的混合物中结晶出来。然后,核糖氨基恶唑啉可以以温和和高效的方式与氰基乙炔反应,给出α胞嘧啶核糖核苷酸。用紫外光进行光异构化,可以实现关于1'异构中心的倒置,从而给出正确的β立体化学。2009年,他们表明,同样的简单构件允许通过磷酸盐控制的核碱基加工,直接获得2',3'-环状嘧啶核苷酸,已知这些核苷酸能够聚合成RNA。这篇文章还强调了嘧啶-2',3'-环状磷酸盐的光致消毒的可能性。<br />
***评论:不依赖模板链的RNA合成***<br />
===RNA structure===<br />
RNA结构<br />
While features of self-organization and self-replication are often considered the hallmark of living systems, there are many instances of abiotic molecules exhibiting such characteristics under proper conditions. Stan Palasek suggested based on a theoretical model that self-assembly of ribonucleic acid (RNA) molecules can occur spontaneously due to physical factors in hydrothermal vents. Virus self-assembly within host cells has implications for the study of the origin of life, as it lends further credence to the hypothesis that life could have started as self-assembling organic molecules.<br />
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虽然自组织和自复制的特征经常被认为是生命系统的标志,但有许多无生命分子在适当条件下表现出这种特征的实例。斯坦·帕拉塞克 Stan Palasek根据理论模型提出,核糖核酸分子(RNA)的自组装可以由于热液喷口的物理因素而自发地发生。病毒在宿主细胞内的自组装对生命起源的研究有启示,因为它进一步证实了生命可能是从自组装有机分子开始的假说。<br />
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===Viral origin===<br />
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病毒的起源 <br />
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Recent evidence for a "virus first" hypothesis, which may support theories of the RNA world, has been suggested. One of the difficulties for the study of the origins of viruses is their high rate of mutation; this is particularly the case in RNA retroviruses like HIV. A 2015 study compared protein fold structures across different branches of the tree of life, where researchers can reconstruct the evolutionary histories of the folds and of the organisms whose genomes code for those folds. They argue that protein folds are better markers of ancient events as their three-dimensional structures can be maintained even as the sequences that code for those begin to change. Thus, the viral protein repertoire retain traces of ancient evolutionary history that can be recovered using advanced bioinformatics approaches. Those researchers think that "the prolonged pressure of genome and particle size reduction eventually reduced virocells into modern viruses (identified by the complete loss of cellular makeup), meanwhile other coexisting cellular lineages diversified into modern cells." The data suggest that viruses originated from ancient cells that co-existed with the ancestors of modern cells. These ancient cells likely contained segmented RNA genomes.<br />
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最近有人提出了"病毒优先”假说的证据,这可能支持RNA世界的理论。研究病毒起源的困难之一是它们的高突变率;尤其是像HIV这样的RNA逆转录病毒。2015年的一项研究比较了生命树不同分支的蛋白质折叠结构,研究人员可以重建折叠和基因组编码这些折叠的生物体的进化史。他们认为,蛋白质折叠是古代事件的更好标志,因为即使编码那些折叠的序列开始变化,它们的三维结构也能保持不变。因此,病毒蛋白库保留了古代进化史的痕迹,可以使用先进的生物信息学方法来恢复。那些研究人员认为,"基因组和颗粒大小减少的长期压力最终将病毒细胞缩减成现代病毒(通过细胞组成的完全丧失来识别),同时其他共存的细胞系也多样化成了现代细胞。"数据表明,病毒起源于与现代细胞的祖先共存的古细胞。这些古细胞很可能包含分段的RNA基因组。<br />
***讨论:那么和病毒最近源的细胞谱系是哪一支呢***<br />
A computational model (2015) has shown that virus capsids may have originated in the RNA world and that they served as a means of horizontal transfer between replicator communities since these communities could not survive if the number of gene parasites increased, with certain genes being responsible for the formation of these structures and those that favored the survival of self-replicating communities. The displacement of these ancestral genes between cellular organisms could favor the appearance of new viruses during evolution. Viruses retain a replication module inherited from the prebiotic stage since it is absent in cells. So this is evidence that viruses could originate from the RNA world and could also emerge several times in evolution through genetic escape in cells.<br />
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一个计算模型(2015)表明,病毒的衣壳可能起源于RNA世界,它们作为复制因子群体之间水平转移的工具,因为如果基因寄生虫的数量增加,这些群体就无法生存,某些基因负责这些结构的形成,而那些基因有利于自复制群体的生存。 这些祖先基因在细胞生物之间的位移可能有利于进化中新病毒的出现。病毒保留了从前生物阶段继承的复制模块,因为它在细胞中是不存在的。所以这是病毒可能起源于RNA世界的证据,也可能在进化中通过细胞中的遗传逃逸而多次出现。<br />
***讨论:阮病毒的出现和某种“位移”或“逃逸”有关吗?这里所谓“从前生物阶段继承的复制模块”是什么呢?***<br />
=== RNA world ===<br />
RNA世界<br />
{{Main|RNA world}}<br />
[[File:Jack-szostak.jpg|thumb|upright|Jack Szostak]]<br />
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杰克·绍斯塔克(Jack Szostak)<br />
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A number of hypotheses of formation of RNA have been put forward. {{As of|1994}}, there were difficulties in the explanation of the abiotic synthesis of the nucleotides cytosine and uracil.<ref>{{cite journal |last=Orgel |first=Leslie E. |date=October 1994 |title=The origin of life on Earth|journal=Scientific American |volume=271 |issue=4 |pages=76–83 |doi=10.1038/scientificamerican1094-76 |pmid=7524147|bibcode=1994SciAm.271d..76O }}</ref> Subsequent research has shown possible routes of synthesis; for example, formamide produces all four ribonucleotides and other biological molecules when warmed in the presence of various terrestrial minerals.<ref name="Saladino2012" /><ref name="Saladino2012b" /> Early cell membranes could have formed spontaneously from proteinoids, which are protein-like molecules produced when amino acid solutions are heated while in the correct concentration of aqueous solution. These are seen to form micro-spheres which are observed to behave similarly to membrane-enclosed compartments. Other possible means of producing more complicated organic molecules include chemical reactions that take place on [[clay]] substrates or on the surface of the mineral [[pyrite]].<br />
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已经提出了RNA的形成的许多假说。截至1994年,在解释核苷酸胞嘧啶和尿嘧啶的非生物合成方面还存在困难。随后的研究表明了可能的合成途径;例如,甲酰胺在各种陆地矿物质存在的情况下加热时可产生所有四种核糖核苷酸和其他生物分子。早期的细胞膜可能是由类蛋白自发形成的,类蛋白是氨基酸溶液在正确浓度的水溶液中加热时产生的蛋白质类分子。这些被视为形成微球体,观察到其行为类似于膜封闭的隔室。其他可能产生更复杂的有机分子的方法包括发生在粘土基质或矿物黄铁矿表面的化学反应。<br />
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Factors supporting an important role for RNA in early life include its ability to act both to store information and to catalyze chemical reactions (as a ribozyme); its many important roles as an intermediate in the expression of and maintenance of the genetic information (in the form of DNA) in modern organisms; and the ease of chemical synthesis of at least the components of the RNA molecule under the conditions that approximated the early Earth.<ref>{{cite journal |last1=Camprubí |first1=E. |last2=de Leeuw|first2=J.W. |last3=House |first3=C.H. |last4=Raulin |first4=F. |last5=Russell |first5=M.J. |last6=Spang|first6=A. | last7=Tirumalai|first7=M.R. |last8=Westall|first8=F. |date=12 December 2019|title=Emergence of Life |journal=Space Sci Rev.|volume=215 |issue=56 |page=56 |doi=10.1007/s11214-019-0624-8 |bibcode=2019SSRv..215...56C |doi-access=free }}</ref><br />
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支持RNA在早期生命中发挥重要作用的因素包括:它既能储存信息,又能催化化学反应(作为核酶);它作为现代生物体内遗传信息(以DNA形式)表达和维持的中间体,发挥着许多重要作用;在近似于早期地球的条件下,至少RNA分子的成分容易化学合成。<br />
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Relatively short RNA molecules have been synthesized, capable of replication.<ref>{{cite journal |last1=Johnston |first1=Wendy K. |last2=Unrau |first2=Peter J. |last3=Lawrence |first3=Michael S. |last4=Glasner |first4=Margaret E. |last5=Bartel |first5=David P. |authorlink5=David Bartel |display-authors=3 |date=18 May 2001 |title=RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension |journal=Science |volume=292 |issue=5520 |pages=1319–1325 |bibcode=2001Sci...292.1319J |doi=10.1126/science.1060786 |pmid=11358999|citeseerx=10.1.1.70.5439 |s2cid=14174984 }}</ref> Such replicase RNA, which functions as both code and catalyst provides its own template upon which copying can occur. Szostak has shown that certain catalytic RNAs can join smaller RNA sequences together, creating the potential for self-replication. If these conditions were present, Darwinian natural selection would favour the proliferation of such [[autocatalytic set]]s, to which further functionalities could be added.<ref>{{cite web |url=http://www.hhmi.org/research/origins-cellular-life |title=The Origins of Function in Biological Nucleic Acids, Proteins, and Membranes |last=Szostak |first=Jack W. |authorlink=Jack W. Szostak |date=5 February 2015 |publisher=[[Howard Hughes Medical Institute]] |location=Chevy Chase (CDP), MD |accessdate=2015-06-16 |url-status=live |archiveurl=https://web.archive.org/web/20150714092225/http://www.hhmi.org/research/origins-cellular-life |archivedate=14 July 2015}}</ref> Such autocatalytic systems of RNA capable of self-sustained replication have been identified.<ref>{{cite journal |last1=Lincoln |first1=Tracey A. |last2=Joyce |first2=Gerald F. |date=27 February 2009 |title=Self-Sustained Replication of an RNA Enzyme |journal=Science |volume=323 |issue=5918 |pages=1229–1232 |bibcode=2009Sci...323.1229L |doi=10.1126/science.1167856 |pmc=2652413 |pmid=19131595}}</ref> The RNA replication systems, which include two ribozymes that catalyze each other's synthesis, showed a doubling time of the product of about one hour, and were subject to natural selection under the conditions that existed in the experiment.<ref name="Joyce2009" /> In evolutionary competition experiments, this led to the emergence of new systems which replicated more efficiently.<ref name="Robertson2012" /> This was the first demonstration of evolutionary adaptation occurring in a molecular genetic system.<ref name="Joyce2009">{{cite journal |last=Joyce |first=Gerald F. |year=2009 |title=Evolution in an RNA world |journal=Cold Spring Harbor Perspectives in Biology |volume=74 |issue=Evolution: The Molecular Landscape |pages=17–23 |doi=10.1101/sqb.2009.74.004 |pmc=2891321 |pmid=19667013 }}</ref><br />
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已经合成了相对较短的RNA分子,能够进行复制。这种复制酶RNA,既起密码,又起催化剂的作用,提供了自己的模板,可以在其上进行复制。Szostak已经证明,某些起催化作用的RNA可以将较小的RNA序列连接在一起,从而产生自复制的潜力。如果具备这些条件,Darwin的自然选择就会有利于这种自催化集的增殖,可以在其上添加进一步的功能。这种能够自我维持复制的RNA自催化系统已经被发现。RNA复制系统包括两个催化彼此的合成的核酶,产物的翻倍时间约为1小时,并且在实验中存在的条件下,受到自然选择的影响。在进化竞争实验中,这导致了新系统的出现,它们的复制效率更高。这是在分子遗传系统中发生进化适应的第一次证明。<br />
***讨论:就算我们最后提出了一种成功的生命起源机制,我们也很难证实地球生命真的是那样起源的***<br />
Depending on the definition, life started when RNA chains began to self-replicate, initiating the three mechanisms of Darwinian selection: [[heritability]], variation of type, and differential reproductive output. The fitness of an RNA replicator (its per capita rate of increase) would likely be a function of its intrinsic adaptive capacities, determined by its nucleotide sequence, and the availability of resources.<ref name="Bernstein">{{cite journal |last1=Bernstein |first1=Harris |last2=Byerly |first2=Henry C. |last3=Hopf |first3=Frederick A. |last4=Michod |first4=Richard A. |last5=Vemulapalli |first5=G. Krishna |display-authors=3 |date=June 1983 |title=The Darwinian Dynamic |journal=[[The Quarterly Review of Biology]] |volume=58 |issue=2 |pages=185–207 |doi=10.1086/413216 |jstor=2828805}}</ref><ref name="Michod 1999">{{harvnb|Michod|1999}}</ref> The three primary adaptive capacities may have been: (1) replication with moderate fidelity, giving rise to both heritability while allowing variation of type, (2) resistance to decay, and (3) acquisition of process resources.<ref name="Bernstein" /><ref name="Michod 1999" /> These capacities would have functioned by means of the folded configurations of the RNA replicators resulting from their nucleotide sequences.<br />
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根据定义,当RNA链开始自复制时,生命就开始了,启动了达尔文选择的三种机制:遗传性、类型的变异和生殖输出差异。一个RNA复制因子的适应性(其人均增长率)很可能是其内在适应能力的函数,由其核苷酸序列以及资源的可用性决定。三种主要的适应能力可能是:(1) 中等保真度的复制,在允许类型变异的同时增加遗传性;(2) 抗衰减能力;(3) 加工资源的获取。 这些能力将通过核苷酸序列产生的RNA复制因子的折叠构型来发挥作用。<br />
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==Experiments on the origin of life==<br />
关于生命起源的实验<br />
[[File:J. Craig Venter crop 2011 CHAO2011-49.jpg|thumb|upright|J. Craig Venter]]<br />
<br />
克雷格·文特<br />
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Both Eigen and [[Sol Spiegelman]] demonstrated that evolution, including replication, variation, and [[natural selection]], can occur in populations of molecules as well as in organisms.<ref name="Follmann2009">{{cite journal |last1= Follmann |first1= Hartmut |last2= Brownson |first2= Carol |date= November 2009 |title= Darwin's warm little pond revisited: from molecules to the origin of life |journal= [[Naturwissenschaften]] |volume= 96 |issue= 11 |pages= 1265–1292 |bibcode= 2009NW.....96.1265F |pmid= 19760276 |doi= 10.1007/s00114-009-0602-1|s2cid= 23259886 }}</ref> Following on from chemical evolution came the initiation of [[Evolution|biological evolution]], which led to the first cells.<ref name="Follmann2009" /> No one has yet synthesized a "[[protocell]]" using simple components with the necessary properties of life (the so-called "[[Top-down and bottom-up design|bottom-up-approach]]"). Without such a proof-of-principle, explanations have tended to focus on [[chemosynthesis]].<ref>{{cite press release |last1= McCollom |first1= Thomas |last2= Mayhew |first2= Lisa |last3= Scott |first3= Jim |date= 7 October 2014 |title= NASA awards CU-Boulder-led team $7 million to study origins, evolution of life in universe |url= http://www.colorado.edu/news/releases/2014/10/07/nasa-awards-cu-boulder-led-team-7-million-study-origins-evolution-life |location= Boulder, CO |publisher= [[University of Colorado Boulder]] |accessdate= 2015-06-08 |url-status= dead |archiveurl= https://web.archive.org/web/20150731015530/http://www.colorado.edu/news/releases/2014/10/07/nasa-awards-cu-boulder-led-team-7-million-study-origins-evolution-life |archivedate= 31 July 2015}}</ref> However, some researchers work in this field, notably [[Steen Rasmussen (physicist)|Steen Rasmussen]] and Szostak.<br />
<br />
Eigen和索尔·斯皮格尔曼 Sol Spiegelman都证明了进化,包括复制、变异和自然选择,可以发生在分子群体中,也可以发生在生物群体中。继化学进化之后,是生物进化的开始,导致了第一个细胞的出现。目前还没有人用简单的成分合成一个具有必要生命特征的"原细胞"(所谓"自下而上的方法")。在没有这样的原理证明的情况下,解释往往集中在化学合成上。然而,一些研究者从事这一领域的研究,著名的有斯蒂恩·拉斯穆森 Steen Rasmussen和Szostak。<br />
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Others have argued that a "[[Top-down and bottom-up design|top-down approach]]" is more feasible, starting with simple forms of current life. Spiegelman took advantage of natural selection to synthesize the [[Spiegelman Monster]], which had a genome with just 218 [[nucleotide]] bases, having deconstructively evolved from a 4500-base bacterial RNA. Eigen built on Spiegelman's work and produced a similar system further degraded to just 48 or 54 nucleotides—the minimum required for the binding of the replication enzyme.<ref name="EIG">{{cite journal|last1=Oehlenschläger|first1=Frank|last2=Eigen|first2=Manfred|authorlink2=Manfred Eigen|date=December 1997|title=30 Years Later – a New Approach to Sol Spiegelman's and Leslie Orgel's in vitro Evolutionary Studies Dedicated to Leslie Orgel on the occasion of his 70th birthday|journal=[[Origins of Life and Evolution of Biospheres]]|volume=27|issue=5–6|pages=437–457|doi=10.1023/A:1006501326129|pmid=9394469|bibcode=1997OLEB...27..437O|s2cid=26717033}}</ref> [[Craig Venter]] and others at [[J. Craig Venter Institute]] engineered existing prokaryotic cells with progressively fewer genes, attempting to discern at which point the most minimal requirements for life are reached.<ref>{{cite journal |last1= Gibson |first1= Daniel G.|last2= Glass |first2= John I. |last3= Lartigue |first3= Carole | last4 = Noskov | first4 = V.| last5 = Chuang | first5 = R.| last6 = Algire | first6 = M.| last7 = Benders | first7 = G.| last8 = Montague | first8 = M.| last9 = Ma | first9 = L.| last10 = Moodie | first10 = M.M.| last11 = Merryman | first11 = C.| last12 = Vashee | first12 = S.| last13 = Krishnakumar | first13 = R.| last14 = Assad-Garcia | first14 = N.| last15 = Andrews-Pfannkoch | first15 = C.| last16 = Denisova | first16 = E.A.| last17 = Young | first17 = L.| last18 = Qi | first18 = Z.-Q.| last19 = Segall-Shapiro | first19 = T.H.| last20 = Calvey | first20 = C.H.| last21 = Parmar | first21 = P.P.| last22 = Hutchison Ca | first22 = C.A.| last23 = Smith | first23 = H.O.| last24 = Venter | first24 = J.C. |display-authors= 3 |date= 2 July 2010 |title= Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome |journal= Science |volume= 329 |issue= 5987 |pages= 52–56 |bibcode= 2010Sci...329...52G |doi= 10.1126/science.1190719 |pmid= 20488990| citeseerx = 10.1.1.167.1455 |s2cid= 7320517}}</ref><ref>{{cite news |last= Swaby |first= Rachel |date= 20 May 2010 |title= Scientists Create First Self-Replicating Synthetic Life |url= https://www.wired.com/2010/05/scientists-create-first-self-replicating-synthetic-life-2/ |work= [[Wired (website)|Wired]] |location= New York |accessdate= 2015-06-08 |url-status= live |archiveurl= https://web.archive.org/web/20150617125555/http://www.wired.com/2010/05/scientists-create-first-self-replicating-synthetic-life-2/ |archivedate= 17 June 2015}}</ref><ref>Coughlan, Andy (2016) "Smallest ever genome comes to life: Humans built it but we don't know what a third of its genes actually do" (New Scientist 2 April 2016 No 3067)p.6</ref><br />
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另一些人则认为"自上而下的方法"更可行,从当前生命的简单形式开始。Spiegelman利用自然选择的优势合成了Spiegelman怪兽,它的基因组只有218个核苷酸碱基,是由4500个碱基的细菌RNA解构进化而来的。Eigen在Spiegelman的研究基础上,制造了一个类似的系统,该系统进一步退化为仅有48或54个核苷酸——这是复制酶结合所需的最低限度。美国克雷格·文特尔研究所 J.Craig Venter研究所的克雷格·文特尔 Craig Venter等人对现有的原核细胞进行了基因逐渐减少的工程,试图分辨出在哪一点上达到了生命的最基本要求。<br />
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In October 2018, researchers at [[McMaster University]] announced the development of a new technology, called a ''[[Planet Simulator]]'', to help study the [[origin of life]] on planet [[Earth]] and beyond.<ref name="BW-20181004">{{cite news |last=Balch |first=Erica |title=Ground-breaking lab poised to unlock the mystery of the origins of life on Earth and beyond |url=https://brighterworld.mcmaster.ca/articles/ground-breaking-lab-poised-to-unlock-the-mystery-of-the-origins-of-life-on-earth-and-beyond/ |date=4 October 2018 |work=[[McMaster University]] |accessdate=4 October 2018 }}</ref><ref name="EA-20181004">{{cite news |author=Staff |title=Ground-breaking lab poised to unlock the mystery of the origins of life |url=https://www.eurekalert.org/pub_releases/2018-10/mu-glp100418.php |date=4 October 2018 |work=[[EurekAlert!]] |accessdate=14 October 2018 }}</ref><ref name="IVG-2018">{{cite web |author=Staff |title=Planet Simulator |url=https://www.intravisiongroup.com/planet-simulator |date=2018 |work=IntraVisionGroup.com |accessdate=14 October 2018 }}</ref><ref name="ES-209181014">{{cite web |last=Anderson |first=Paul Scott |title=New technology may help solve mystery of life's origins – How did life on Earth begin? A new technology, called Planet Simulator, might finally help solve the mystery. |url=http://earthsky.org/space/new-technology-solve-mystery-of-lifes-origins |date=14 October 2018 |work=[[EarthSky]] |accessdate=14 October 2018 }}</ref> It consists of a sophisticated climate chamber to study how the building blocks of life were assembled and how these prebiotic molecules transitioned into self-replicating RNA molecules.<ref name="BW-20181004"/><br />
<br />
2018年10月,麦克马斯特大学的研究人员宣布开发出一种名为"行星模拟器"的新技术,以帮助研究地球及其他星球上生命的起源。它由一个复杂的气候室组成,以研究生命的构件是如何组装的,以及这些前生物分子如何过渡到自我复制的RNA分子。<br />
<br />
== See also ==<br />
另请参阅<br />
{{div col}}<br />
* {{annotated link|Anthropic principle}} Anthropic principle – Philosophical premise that all scientific observations presuppose a universe compatible with the emergence of sentient organisms that make those observations<br />
人类学原理--哲学前提,即所有的科学观察都预设了一个宇宙,与使这些观察得以实现的有意识生物的出现相适应。<br />
* {{annotated link|Artificial cell}} 人工细胞<br />
* {{annotated link|Artificial life}} Artificial life – A field of study wherein researchers examine systems related to natural life, its processes, and its evolution, through the use of simulations 人工生命——研究人员通过使用模拟技术,对与自然生命相关的系统、其过程和进化进行研究的一个研究领域。<br />
* {{annotated link|Bathybius haeckelii}}海克尔深水虫<br />
* {{annotated link|Entropy and life}} 熵与生命<br />
* {{annotated link|Formamide-based prebiotic chemistry}} 基于甲酰胺的生命起源以前的化学<br />
* {{annotated link|GADV-protein world hypothesis}} GADV-蛋白世界假说<br />
* {{annotated link|Hemolithin}} Hemolithin – Protein claimed to be of extraterrestrial origin 血石蛋白——据称来自外星的蛋白质。<br />
* {{annotated link|Hypothetical types of biochemistry}} Hypothetical types of biochemistry – Possible alternative biochemicals used by life forms 假设的生物化学类型----生命形式可能使用的替代性生物化学物。<br />
* {{annotated link|Mediocrity principle}} 平庸原则<br />
* {{annotated link|Nexus for Exoplanet System Science}} Nexus for Exoplanet System Science – Dedicated to the search for life on exoplanets 外行星系统科学联盟--致力于寻找外行星上的生命。<br />
* {{annotated link|Noogenesis}} Noogenesis – Emergence and evolution of intelligence 心理演化——智慧的出现和进化<br />
* {{annotated link|Planetary habitability}} Planetary habitability – Extent to which a planet is suitable for life as we know it 行星宜居性--行星适合我们所知的生命的程度。<br />
* {{annotated link|Protocell}} Protocell – Lipid globule proposed as a precursor of living cells 原细胞--被认为是活细胞的前体的脂质球。<br />
* {{annotated link|Rare Earth hypothesis}} Rare Earth hypothesis – Hypothesis that complex extraterrestrial life is improbable and extremely rare 地球罕见假说--认为复杂的地外生命是不大可能的,而且极其罕见的假说。<br />
* {{annotated link|Shadow biosphere}} Shadow biosphere – A hypothetical microbial biosphere of Earth that would use radically different biochemical and molecular processes from that of currently known life 影子生物圈 -- -- 假设的地球微生物生物圈,将使用与目前已知生命完全不同的生化和分子过程。<br />
* {{annotated link|Tholin}} Tholin – Class of molecules formed by ultraviolet irradiation of organic compounds 托林--有机化合物经紫外线照射形成的一类分子。<br />
{{div col end}}<br />
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[[Category:待整理页面]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E8%81%94%E5%90%88%E7%86%B5&diff=20871
联合熵
2021-01-12T16:01:57Z
<p>Thingamabob:/* Definition 定义 */</p>
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<div>此词条Jie翻译。由CecileLi初步审校。文中部分公式内容未正常显示,有“模板”点击打开后却没有内容,还有未显示去掉格式后的英文,不清楚是程序错误还是未编辑完成orz······<br />
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{{Short description|Measure of information in probability and information theory}}<br />
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{{Information theory}}<br />
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[[文件:Entropy-mutual-information-relative-entropy-relation-diagram.svg|缩略图|右|该图表示在变量X、Y相关联的各种信息量之间,进行加减关系的维恩图。两个圆重合的区域是联合熵H(X,Y)。左侧的圆(红色和紫色)是单个熵H(X),红色是条件熵H(X ǀ Y)。右侧的圆(蓝色和紫色)为H(Y),蓝色为H(Y ǀ X)。中间紫色的是相互信息i(X; Y)。]]<br />
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In [[information theory]], '''joint [[entropy (information theory)|entropy]]''' is a measure of the uncertainty associated with a set of [[random variables|variables]].<ref name=korn>{{cite book |author1=Theresa M. Korn |author2=Korn, Granino Arthur |title=Mathematical Handbook for Scientists and Engineers: Definitions, Theorems, and Formulas for Reference and Review |publisher=Dover Publications |location=New York |year= |isbn=0-486-41147-8 |oclc= |doi=}}</ref><br />
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在'''<font color="#ff8000"> 信息论Information theory</font>'''中,'''<font color="#ff8000"> 联合熵Joint entropy</font>'''是用于对与一组变量相关的不确定性进行度量。<br />
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==Definition 定义 ==<br />
The joint [[Shannon entropy]] (in [[bit]]s) of two discrete [[random variable|random variables]] <math>X</math> and <math>Y</math> with images <math>\mathcal X</math> and <math>\mathcal Y</math> is defined as<ref name=cover1991>{{cite book |author1=Thomas M. Cover |author2=Joy A. Thomas |title=Elements of Information Theory |publisher=Wiley |location=Hoboken, New Jersey |year= |isbn=0-471-24195-4}}</ref>{{rp|16}}<br />
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联合熵Shannon entropy </font>'''的定义是:以比特为单位,对于具有<math>\mathcal X</math>和<math>\mathcal Y</math>的两个离散随机变量函数<math>X</math>和<math>Y</math>'''有<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>\Eta(X,Y) = -\sum_{x\in\mathcal X} \sum_{y\in\mathcal Y} P(x,y) \log_2[P(x,y)]</math>|{{EquationRef|Eq.1}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
<br />
where <math>x</math> and <math>y</math> are particular values of <math>X</math> and <math>Y</math>, respectively, <math>P(x,y)</math> is the [[joint probability]] of these values occurring together, and <math>P(x,y) \log_2[P(x,y)]</math> is defined to be 0 if <math>P(x,y)=0</math>.<br />
<br />
其中<math>x</math>和<math>y</math>分别是<math>X</math>和<math>Y</math>的特定值,<math>P(x,y)</math>是这些值产生交集时的联合概率,如果<math>P(x,y)=0</math>那么<math>P(x,y) \log_2[P(x,y)]</math>定义为0。<br />
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For more than two random variables <math>X_1, ..., X_n</math> this expands to<br />
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对于两个以上的随机变量<math>X_1, ..., X_n</math>,它扩展为<br />
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<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>\Eta(X_1, ..., X_n) = <br />
-\sum_{x_1 \in\mathcal X_1} ... \sum_{x_n \in\mathcal X_n} P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math>|{{EquationRef|Eq.2}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
<br />
where <math>x_1,...,x_n</math> are particular values of <math>X_1,...,X_n</math>, respectively, <math>P(x_1, ..., x_n)</math> is the probability of these values occurring together, and <math>P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math> is defined to be 0 if <math>P(x_1, ..., x_n)=0</math>.<br />
<br />
其中<math>x_1,...,x_n</math>分别是<math>X_1,...,X_n</math>的特定值,<math>P(x_1, ..., x_n)</math>是这些值产生交集的概率,如果<math>P(x_1, ..., x_n)=0</math>那么<math>P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math>定义为0。<br />
<br />
== Properties 属性 ==<br />
<br />
===Nonnegativity 非负性===<br />
The joint entropy of a set of random variables is a nonnegative number.<br />
<br />
一组随机变量的联合熵是一个非负数。<br />
<br />
<br />
:<math>H(X,Y) \geq 0</math><br />
<br />
:<math>H(X_1,\ldots, X_n) \geq 0</math><br />
<br />
<br />
<br />
=== Greater than r equal to the maximum of all of the individual entropies 高值性/最值性/大于或等于单个熵的最大值===<br />
<br />
The joint entropy of a set of variables is greater than or equal to the maximum of all of the individual entropies of the variables in the set.<br />
<br />
一组变量的联合熵大于或等于该组变量的所有单个熵的最大值。<br />
<br />
<br />
:<math>H(X,Y) \geq \max \left[H(X),H(Y) \right]</math><br />
<br />
:<math>H \bigl(X_1,\ldots, X_n \bigr) \geq \max_{1 \le i \le n} <br />
\Bigl\{H\bigl(X_i\bigr) \Bigr\}</math><br />
<br />
=== Less than or equal to the sum of individual entropies 低值性/小于或等于单个熵的总和===<br />
<br />
The joint entropy of a set of variables is less than or equal to the sum of the individual entropies of the variables in the set. This is an example of [[subadditivity]]. This inequality is an equality if and only if <math>X</math> and <math>Y</math> are [[statistically independent]].<ref name=cover1991 />{{rp|30}}<br />
<br />
一组变量的联合熵小于或等于该组变量各个熵的总和,这是次可加性的一个运用实例。即当且仅当<math>X</math>和<math>Y</math>独立统计时,该不等式才是等式。<ref name=cover1991 />{{rp|30}}<br />
<br />
<br />
:<math>H(X,Y) \leq H(X) + H(Y)</math><br />
<br />
:<math>H(X_1,\ldots, X_n) \leq H(X_1) + \ldots + H(X_n)</math><br />
<br />
== Relations to other entropy measures 与其他熵测度的关系 ==<br />
<br />
Joint entropy is used in the definition of [[conditional entropy]]<ref name=cover1991 />{{rp|22}}<br />
<br />
联合熵被用于定义'''<font color="#ff8000"> 条件熵Conditional entropy </font>''':<br />
<br />
<br />
:<math>H(X|Y) = H(X,Y) - H(Y)\,</math>,<br />
<br />
and <math display="block">H(X_1,\dots,X_n) = \sum_{k=1}^n H(X_k|X_{k-1},\dots, X_1)</math><br />
<br />
<br />
It is also used in the definition of [[mutual information]]<ref name=cover1991 />{{rp|21}}<br />
它也被用于定义'''<font color="#ff8000"> 交互信息Mutual information</font>''':<br />
<br />
<br />
:<math>\operatorname{I}(X;Y) = H(X) + H(Y) - H(X,Y)\,</math><br />
<br />
<br />
In [[quantum information theory]], the joint entropy is generalized into the [[joint quantum entropy]].<br />
<br />
在'''<font color="#ff8000"> 量子信息论Quantum information theory</font>'''中,使用的是广义化的联合熵,即'''<font color="#ff8000"> 联合量子熵Joint quantum entropy</font>'''。<br />
<br />
<br />
<br />
=== Applications 应用 ===<br />
<br />
A python package for computing all multivariate joint entropies, mutual informations, conditional mutual information, total correlations, information distance in a dataset of n variables is available.<ref>{{cite web|url=https://infotopo.readthedocs.io/en/latest/index.html|title=InfoTopo: Topological Information Data Analysis. Deep statistical unsupervised and supervised learning - File Exchange - Github|author=|date=|website=github.com/pierrebaudot/infotopopy/|accessdate=26 September 2020}}</ref><br />
<br />
在这里我们提供了一个python软件包,可用于计算n个变量的数据集中的所有多元联合熵、交互信息、条件交互信息、总相关性以及信息距离。<br />
<br />
== Joint differential entropy 联合微分熵 ==<br />
=== Definition 定义 ===<br />
<br />
The above definition is for discrete random variables and just as valid in the case of continuous random variables. The continuous version of discrete joint entropy is called ''joint differential (or continuous) entropy''. Let <math>X</math> and <math>Y</math> be a continuous random variables with a [[joint probability density function]] <math>f(x,y)</math>. The differential joint entropy <math>h(X,Y)</math> is defined as<ref name=cover1991 />{{rp|249}}<br />
<br />
上文中的定义是针对离散随机变量的,而其实对于连续随机变量,联合熵同样成立。离散联合熵的连续形式称为联合微分(或连续)熵。令<math>X</math>和<math>Y</math>分别为具有'''<font color="#ff8000"> 联合概率密度函数Joint probability density function</font>''' <math>f(x,y)</math>的连续随机变量,那么微分联合熵<math>h(X,Y)</math>定义为:<br />
<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>h(X,Y) = -\int_{\mathcal X , \mathcal Y} f(x,y)\log f(x,y)\,dx dy</math>|{{EquationRef|Eq.3}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
For more than two continuous random variables <math>X_1, ..., X_n</math> the definition is generalized to:<br />
<br />
对于两个以上的连续随机变量<math>X_1, ..., X_n</math>,其定义可概括为:<br />
<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>h(X_1, \ldots,X_n) = -\int f(x_1, \ldots,x_n)\log f(x_1, \ldots,x_n)\,dx_1 \ldots dx_n</math>|{{EquationRef|Eq.4}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
<br />
The [[integral]] is taken over the support of <math>f</math>. It is possible that the integral does not exist in which case we say that the differential entropy is not defined.<br />
<br />
这里可以用积分处理表达<math>f</math>。当然,如果微分熵没有定义,那么积分也可能不存在。<br />
<br />
=== Properties 属性 ===<br />
As in the discrete case the joint differential entropy of a set of random variables is smaller or equal than the sum of the entropies of the individual random variables:<br />
<br />
与离散条件下的联合熵相似,联合微分熵也具有同样的属性,即:一组随机变量的联合微分熵小于或等于各个随机变量的熵之和:<br />
<br />
<br />
:<math>h(X_1,X_2, \ldots,X_n) \le \sum_{i=1}^n h(X_i)</math><ref name=cover1991 />{{rp|253}}<br />
<br />
<br />
The following chain rule holds for two random variables:<br />
<br />
以下链式法则适用于两个随机变量:<br />
<br />
<br />
:<math>h(X,Y) = h(X|Y) + h(Y)</math><br />
<br />
<br />
In the case of more than two random variables this generalizes to:<ref name=cover1991 />{{rp|253}}<br />
<br />
对于两个以上的随机变量,一般可归纳为:<br />
<br />
<br />
:<math>h(X_1,X_2, \ldots,X_n) = \sum_{i=1}^n h(X_i|X_1,X_2, \ldots,X_{i-1})</math><br />
<br />
<br />
Joint differential entropy is also used in the definition of the [[mutual information]] between continuous random variables:<br />
<br />
联合微分熵也用于定义连续随机变量之间的交互信息:<br />
<br />
<br />
:<math>\operatorname{I}(X,Y)=h(X)+h(Y)-h(X,Y)</math><br />
<br />
== References 参考文献 ==<br />
{{Reflist}}<br />
<br />
[[Category:Entropy and information]]<br />
<br />
[[de:Bedingte Entropie#Blockentropie]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E8%81%94%E5%90%88%E7%86%B5&diff=20870
联合熵
2021-01-12T16:01:35Z
<p>Thingamabob:/* Definition 定义 */</p>
<hr />
<div>此词条Jie翻译。由CecileLi初步审校。文中部分公式内容未正常显示,有“模板”点击打开后却没有内容,还有未显示去掉格式后的英文,不清楚是程序错误还是未编辑完成orz······<br />
<br />
{{Short description|Measure of information in probability and information theory}}<br />
<br />
{{Information theory}}<br />
<br />
[[文件:Entropy-mutual-information-relative-entropy-relation-diagram.svg|缩略图|右|该图表示在变量X、Y相关联的各种信息量之间,进行加减关系的维恩图。两个圆重合的区域是联合熵H(X,Y)。左侧的圆(红色和紫色)是单个熵H(X),红色是条件熵H(X ǀ Y)。右侧的圆(蓝色和紫色)为H(Y),蓝色为H(Y ǀ X)。中间紫色的是相互信息i(X; Y)。]]<br />
<br />
<br />
In [[information theory]], '''joint [[entropy (information theory)|entropy]]''' is a measure of the uncertainty associated with a set of [[random variables|variables]].<ref name=korn>{{cite book |author1=Theresa M. Korn |author2=Korn, Granino Arthur |title=Mathematical Handbook for Scientists and Engineers: Definitions, Theorems, and Formulas for Reference and Review |publisher=Dover Publications |location=New York |year= |isbn=0-486-41147-8 |oclc= |doi=}}</ref><br />
<br />
在'''<font color="#ff8000"> 信息论Information theory</font>'''中,'''<font color="#ff8000"> 联合熵Joint entropy</font>'''是用于对与一组变量相关的不确定性进行度量。<br />
<br />
<br />
<br />
==Definition 定义 ==<br />
The joint [[Shannon entropy]] (in [[bit]]s) of two discrete [[random variable|random variables]] <math>X</math> and <math>Y</math> with images <math>\mathcal X</math> and <math>\mathcal Y</math> is defined as<ref name=cover1991>{{cite book |author1=Thomas M. Cover |author2=Joy A. Thomas |title=Elements of Information Theory |publisher=Wiley |location=Hoboken, New Jersey |year= |isbn=0-471-24195-4}}</ref>{{rp|16}}<br />
<br />
联合熵Shannon entropy </font>'''的定义是:以比特为单位,对于具有<math>\mathcal X</math>和<math>\mathcal Y</math>的两个离散随机变量函数<math>X</math>和<math>Y</math>'''有<font color="#ff8000"> <br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>\Eta(X,Y) = -\sum_{x\in\mathcal X} \sum_{y\in\mathcal Y} P(x,y) \log_2[P(x,y)]</math>|{{EquationRef|Eq.1}}}}<br />
|cellpadding= 6<br />
<br />
<br />
<br />
where <math>x</math> and <math>y</math> are particular values of <math>X</math> and <math>Y</math>, respectively, <math>P(x,y)</math> is the [[joint probability]] of these values occurring together, and <math>P(x,y) \log_2[P(x,y)]</math> is defined to be 0 if <math>P(x,y)=0</math>.<br />
<br />
其中<math>x</math>和<math>y</math>分别是<math>X</math>和<math>Y</math>的特定值,<math>P(x,y)</math>是这些值产生交集时的联合概率,如果<math>P(x,y)=0</math>那么<math>P(x,y) \log_2[P(x,y)]</math>定义为0。<br />
<br />
<br />
<br />
For more than two random variables <math>X_1, ..., X_n</math> this expands to<br />
<br />
对于两个以上的随机变量<math>X_1, ..., X_n</math>,它扩展为<br />
<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>\Eta(X_1, ..., X_n) = <br />
-\sum_{x_1 \in\mathcal X_1} ... \sum_{x_n \in\mathcal X_n} P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math>|{{EquationRef|Eq.2}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
<br />
where <math>x_1,...,x_n</math> are particular values of <math>X_1,...,X_n</math>, respectively, <math>P(x_1, ..., x_n)</math> is the probability of these values occurring together, and <math>P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math> is defined to be 0 if <math>P(x_1, ..., x_n)=0</math>.<br />
<br />
其中<math>x_1,...,x_n</math>分别是<math>X_1,...,X_n</math>的特定值,<math>P(x_1, ..., x_n)</math>是这些值产生交集的概率,如果<math>P(x_1, ..., x_n)=0</math>那么<math>P(x_1, ..., x_n) \log_2[P(x_1, ..., x_n)]</math>定义为0。<br />
<br />
== Properties 属性 ==<br />
<br />
===Nonnegativity 非负性===<br />
The joint entropy of a set of random variables is a nonnegative number.<br />
<br />
一组随机变量的联合熵是一个非负数。<br />
<br />
<br />
:<math>H(X,Y) \geq 0</math><br />
<br />
:<math>H(X_1,\ldots, X_n) \geq 0</math><br />
<br />
<br />
<br />
=== Greater than r equal to the maximum of all of the individual entropies 高值性/最值性/大于或等于单个熵的最大值===<br />
<br />
The joint entropy of a set of variables is greater than or equal to the maximum of all of the individual entropies of the variables in the set.<br />
<br />
一组变量的联合熵大于或等于该组变量的所有单个熵的最大值。<br />
<br />
<br />
:<math>H(X,Y) \geq \max \left[H(X),H(Y) \right]</math><br />
<br />
:<math>H \bigl(X_1,\ldots, X_n \bigr) \geq \max_{1 \le i \le n} <br />
\Bigl\{H\bigl(X_i\bigr) \Bigr\}</math><br />
<br />
=== Less than or equal to the sum of individual entropies 低值性/小于或等于单个熵的总和===<br />
<br />
The joint entropy of a set of variables is less than or equal to the sum of the individual entropies of the variables in the set. This is an example of [[subadditivity]]. This inequality is an equality if and only if <math>X</math> and <math>Y</math> are [[statistically independent]].<ref name=cover1991 />{{rp|30}}<br />
<br />
一组变量的联合熵小于或等于该组变量各个熵的总和,这是次可加性的一个运用实例。即当且仅当<math>X</math>和<math>Y</math>独立统计时,该不等式才是等式。<ref name=cover1991 />{{rp|30}}<br />
<br />
<br />
:<math>H(X,Y) \leq H(X) + H(Y)</math><br />
<br />
:<math>H(X_1,\ldots, X_n) \leq H(X_1) + \ldots + H(X_n)</math><br />
<br />
== Relations to other entropy measures 与其他熵测度的关系 ==<br />
<br />
Joint entropy is used in the definition of [[conditional entropy]]<ref name=cover1991 />{{rp|22}}<br />
<br />
联合熵被用于定义'''<font color="#ff8000"> 条件熵Conditional entropy </font>''':<br />
<br />
<br />
:<math>H(X|Y) = H(X,Y) - H(Y)\,</math>,<br />
<br />
and <math display="block">H(X_1,\dots,X_n) = \sum_{k=1}^n H(X_k|X_{k-1},\dots, X_1)</math><br />
<br />
<br />
It is also used in the definition of [[mutual information]]<ref name=cover1991 />{{rp|21}}<br />
它也被用于定义'''<font color="#ff8000"> 交互信息Mutual information</font>''':<br />
<br />
<br />
:<math>\operatorname{I}(X;Y) = H(X) + H(Y) - H(X,Y)\,</math><br />
<br />
<br />
In [[quantum information theory]], the joint entropy is generalized into the [[joint quantum entropy]].<br />
<br />
在'''<font color="#ff8000"> 量子信息论Quantum information theory</font>'''中,使用的是广义化的联合熵,即'''<font color="#ff8000"> 联合量子熵Joint quantum entropy</font>'''。<br />
<br />
<br />
<br />
=== Applications 应用 ===<br />
<br />
A python package for computing all multivariate joint entropies, mutual informations, conditional mutual information, total correlations, information distance in a dataset of n variables is available.<ref>{{cite web|url=https://infotopo.readthedocs.io/en/latest/index.html|title=InfoTopo: Topological Information Data Analysis. Deep statistical unsupervised and supervised learning - File Exchange - Github|author=|date=|website=github.com/pierrebaudot/infotopopy/|accessdate=26 September 2020}}</ref><br />
<br />
在这里我们提供了一个python软件包,可用于计算n个变量的数据集中的所有多元联合熵、交互信息、条件交互信息、总相关性以及信息距离。<br />
<br />
== Joint differential entropy 联合微分熵 ==<br />
=== Definition 定义 ===<br />
<br />
The above definition is for discrete random variables and just as valid in the case of continuous random variables. The continuous version of discrete joint entropy is called ''joint differential (or continuous) entropy''. Let <math>X</math> and <math>Y</math> be a continuous random variables with a [[joint probability density function]] <math>f(x,y)</math>. The differential joint entropy <math>h(X,Y)</math> is defined as<ref name=cover1991 />{{rp|249}}<br />
<br />
上文中的定义是针对离散随机变量的,而其实对于连续随机变量,联合熵同样成立。离散联合熵的连续形式称为联合微分(或连续)熵。令<math>X</math>和<math>Y</math>分别为具有'''<font color="#ff8000"> 联合概率密度函数Joint probability density function</font>''' <math>f(x,y)</math>的连续随机变量,那么微分联合熵<math>h(X,Y)</math>定义为:<br />
<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>h(X,Y) = -\int_{\mathcal X , \mathcal Y} f(x,y)\log f(x,y)\,dx dy</math>|{{EquationRef|Eq.3}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
For more than two continuous random variables <math>X_1, ..., X_n</math> the definition is generalized to:<br />
<br />
对于两个以上的连续随机变量<math>X_1, ..., X_n</math>,其定义可概括为:<br />
<br />
<br />
{{Equation box 1<br />
|indent =<br />
|title=<br />
|equation = {{NumBlk||<math>h(X_1, \ldots,X_n) = -\int f(x_1, \ldots,x_n)\log f(x_1, \ldots,x_n)\,dx_1 \ldots dx_n</math>|{{EquationRef|Eq.4}}}}<br />
|cellpadding= 6<br />
|border<br />
|border colour = #0073CF<br />
|background colour=#F5FFFA}}<br />
<br />
<br />
The [[integral]] is taken over the support of <math>f</math>. It is possible that the integral does not exist in which case we say that the differential entropy is not defined.<br />
<br />
这里可以用积分处理表达<math>f</math>。当然,如果微分熵没有定义,那么积分也可能不存在。<br />
<br />
=== Properties 属性 ===<br />
As in the discrete case the joint differential entropy of a set of random variables is smaller or equal than the sum of the entropies of the individual random variables:<br />
<br />
与离散条件下的联合熵相似,联合微分熵也具有同样的属性,即:一组随机变量的联合微分熵小于或等于各个随机变量的熵之和:<br />
<br />
<br />
:<math>h(X_1,X_2, \ldots,X_n) \le \sum_{i=1}^n h(X_i)</math><ref name=cover1991 />{{rp|253}}<br />
<br />
<br />
The following chain rule holds for two random variables:<br />
<br />
以下链式法则适用于两个随机变量:<br />
<br />
<br />
:<math>h(X,Y) = h(X|Y) + h(Y)</math><br />
<br />
<br />
In the case of more than two random variables this generalizes to:<ref name=cover1991 />{{rp|253}}<br />
<br />
对于两个以上的随机变量,一般可归纳为:<br />
<br />
<br />
:<math>h(X_1,X_2, \ldots,X_n) = \sum_{i=1}^n h(X_i|X_1,X_2, \ldots,X_{i-1})</math><br />
<br />
<br />
Joint differential entropy is also used in the definition of the [[mutual information]] between continuous random variables:<br />
<br />
联合微分熵也用于定义连续随机变量之间的交互信息:<br />
<br />
<br />
:<math>\operatorname{I}(X,Y)=h(X)+h(Y)-h(X,Y)</math><br />
<br />
== References 参考文献 ==<br />
{{Reflist}}<br />
<br />
[[Category:Entropy and information]]<br />
<br />
[[de:Bedingte Entropie#Blockentropie]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7%E8%AE%A8%E8%AE%BA:Thingamabob&diff=19483
用户讨论:Thingamabob
2020-11-30T02:36:00Z
<p>Thingamabob:清空全部内容</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%A6%82%E7%8E%87%E5%88%86%E5%B8%83&diff=19357
概率分布
2020-11-29T13:26:18Z
<p>Thingamabob:/* Common probability distributions and their applications 共同概率分布及其应用 */</p>
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<div>本词条由Ryan初步翻译<br />
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{{short description|Mathematical function that describes the probability of occurrence of different possible outcomes in an experiment}}<br />
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{{other uses|Distribution (disambiguation){{!}}Distribution}}<br />
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{{Off topic|date=August 2020|Random variable|talksectionheading}}<br />
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In [[probability theory]] and [[statistics]], a '''probability distribution''' is the mathematical [[Function (mathematics)|function]] that gives the probabilities of occurrence of different possible '''outcomes''' for an [[Experiment (probability theory)|experiment]].<ref name=":02">{{Cite book|title=The Cambridge dictionary of statistics|last=Everitt, Brian.|date=2006|publisher=Cambridge University Press|isbn=978-0-511-24688-3|edition=3rd|location=Cambridge, UK|oclc=161828328}}</ref><ref>{{Cite book|title=Basic probability theory|last=Ash, Robert B.|date=2008|publisher=Dover Publications|isbn=978-0-486-46628-6|edition=Dover|location=Mineola, N.Y.|pages=66–69|oclc=190785258}}</ref> It is a mathematical description of a [[Randomness|random]] phenomenon in terms of its [[sample space]] and the [[Probability|probabilities]] of [[Event (probability theory)|events]] (subsets of the sample space).<ref name=":1">{{Cite book|title=Probability and statistics : the science of uncertainty|last=Evans, Michael (Michael John)|date=2010|publisher=W.H. Freeman and Co|others=Rosenthal, Jeffrey S. (Jeffrey Seth)|isbn=978-1-4292-2462-8|edition=2nd|location=New York|pages=38|oclc=473463742}}</ref><br />
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In Probability Theory and Statistics, a Probability Distribution is the mathematical function that gives the probabilities of occurrence of different possible outcomes for an experiment. It is a mathematical description of a random phenomenon in terms of its sample space and the probabilities of events (subsets of the sample space).<br />
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在'''<font color="#ff8000">概率论 Probability Theory</font>'''和'''<font color="#ff8000">统计学 Statistics</font>'''中,'''<font color="#ff8000"> 概率分布 Probability Distribution</font>'''是一个给出一个实验不同可能结果出现的概率的数学函数。它是根据'''<font color="#ff8000"> 样本空间 Sample Space</font>'''和'''<font color="#ff8000"> 事件概率 Probabilities of Events</font>'''(样本空间的子集)对随机现象的数学描述。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“'''<font color="#ff8000"> 概率分布 Probability Distribution</font>'''是一个给出一个实验不同可能结果出现的概率的数学函数。”一句改为“'''<font color="#ff8000"> 概率分布 Probability Distribution</font>'''是一个数学函数,它给出一个试验不同可能结果出现的概率。”<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“它是根据'''<font color="#ff8000"> 样本空间 Sample Space</font>'''和'''<font color="#ff8000"> 事件概率 Probabilities of Events</font>'''(样本空间的子集)对随机现象的数学描述。”一句中“(样本空间的子集)”改为“(事件即样本空间的子集)”。<br />
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For instance, if the [[random variable]] {{mvar|X}} is used to denote the outcome of a coin toss ("the experiment"), then the probability distribution of {{mvar|X}} would take the value 0.5 for {{math|''X''&nbsp;{{=}} heads}}, and 0.5 for {{math|''X''&nbsp;{{=}} tails}} (assuming the coin is fair). Examples of random phenomena include the weather condition in a future date, the height of a person, the fraction of male students in a school, the results of a [[Survey methodology|survey]], etc.<ref name="ross">{{cite book|first=Sheldon M.|last=Ross|title=A first course in probability|publisher=Pearson|year=2010}}</ref><br />
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For instance, if the random variable X is used to denote the outcome of a coin toss ("the experiment"), then the probability distribution of X would take the value 0.5 for X=heads, and 0.5 for X=tails (assuming the coin is fair). Examples of random phenomena include the weather condition in a future date, the height of a person, the fraction of male students in a school, the results of a survey, etc.<br />
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例如,如果使用随机变量来表示掷硬币的结果(“实验”) ,那么硬币为正面的概率分布为0.5,反面的值0.5(假设硬币是公平的)。随机现象的例子包括未来某一天的天气状况、一个人的身高、学校中男生的比例、调查结果等等。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“例如,如果使用随机变量来表示掷硬币的结果(“实验”) ,那么硬币为正面的概率分布为0.5,反面的值0.5(假设硬币是公平的)。”一句改为“例如,如果使用随机变量{{mvar|X}}来表示掷硬币(“试验”)的结果,那么{{mvar|X}}的概率分布是:{{math|''X''&nbsp;{{=}} 正面}}的概率值为0.5,{{math|''X''&nbsp;{{=}} 反面}}的概率值为0.5(假设硬币是公平的)。”<br />
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A probability distribution is a mathematical function that has a [[sample space]] as its '''input''', and gives a '''probability''' as its output. The sample space is the [[Set (mathematics)|set]] of all possible [[Outcome (probability)|outcomes]] of a random phenomenon being observed; it may be the set of [[real numbers]] or a set of [[vector (mathematics)|vectors]], or it may be a list of non-numerical values. For example, the sample space of a coin flip would be {{math|{heads, tails} }}.<br />
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A probability distribution is a mathematical function that has a sample space as its input, and gives a probability as its output. The sample space is the set of all possible outcomes of a random phenomenon being observed; it may be the set of real numbers or a set of vectors, or it may be a list of non-numerical values. For example, the sample space of a coin flip would be .<br />
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概率分布是一个数学函数,它的输入是一个样本空间,输出是一个概率。样本空间是所观察到的随机现象的所有可能结果的集合; 它可能是一组实数或一组向量,也可能是一组非数值。例如,抛硬币的样本空间是{头,尾}。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“它可能是一组实数或一组向量,也可能是一组非数值。例如,抛硬币的样本空间是{头,尾}。”一句改为“它可能是实数的集合或向量的集合,也可能是非数值的集合。例如,抛硬币的样本空间是{正面,反面}。”<br />
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Probability distributions are generally divided into two classes. A '''discrete probability distribution''' is applicable to the scenarios where the set of possible outcomes is [[discrete probability distribution|discrete]] (e.g. a coin toss or the roll of a dice), and the probabilities are here encoded by a discrete list of the probabilities of the outcomes, known as the [[probability mass function]]. On the other hand, '''continuous probability distributions''' are applicable to scenarios where the set of possible outcomes can take on values in a continuous range (e.g. real numbers), such as the temperature on a given day. In this case, probabilities are typically described by a [[probability density function]].<ref name="ross" /><ref>{{cite book|author1=DeGroot, Morris H.|author2=Schervish, Mark J.|title=Probability and Statistics|publisher=Addison-Wesley|year=2002}}</ref> The [[normal distribution]] is a commonly encountered continuous probability distribution. More complex experiments, such as those involving [[stochastic processes]] defined in [[continuous time]], may demand the use of more general [[probability measure]]s.<br />
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Probability distributions are generally divided into two classes. A discrete probability distribution is applicable to the scenarios where the set of possible outcomes is discrete (e.g. a coin toss or the roll of a dice), and the probabilities are here encoded by a discrete list of the probabilities of the outcomes, known as the probability mass function. On the other hand, continuous probability distributions are applicable to scenarios where the set of possible outcomes can take on values in a continuous range (e.g. real numbers), such as the temperature on a given day. In this case, probabilities are typically described by a probability density function. The normal distribution is a commonly encountered continuous probability distribution. More complex experiments, such as those involving stochastic processes defined in continuous time, may demand the use of more general probability measures.<br />
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概率分布一般分为两类。'''<font color="#ff8000"> 离散概率分布 Discrete Probability Distribution</font>'''适用于一组可能的结果是离散的情况,如抛硬币或掷骰子。这里的概率被编码为结果概率的离散列表,称为概率质量函数。另一方面,'''<font color="#ff8000"> 连续概率分布 Continuous Probability Distribution</font>'''适用于一组可以在一个连续的范围内取值的结果的情况(例如:实数),例如某一天的温度。在这种情况下,概率通常由概率密度函数描述。'''<font color="#ff8000"> 正态分布 Normal Distribution</font>'''是一种常见的连续概率分布。更复杂的实验,例如那些涉及连续时间定义的随机过程的实验,可能需要使用更一般的概率测度。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“'''<font color="#ff8000"> 离散概率分布 Discrete Probability Distribution</font>'''适用于一组可能的结果是离散的情况”一句中“一组可能的结果”改为“可能结果的集合”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“'''<font color="#ff8000"> 连续概率分布 Continuous Probability Distribution</font>'''适用于一组可以在一个连续的范围内取值的结果的情况”一句中“一组可以在一个连续的范围内取值的结果”改为“可能结果集在连续范围内取值”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“更复杂的实验,例如那些涉及连续时间定义的随机过程的实验,可能需要使用更一般的概率测度。”一句改为“更复杂的试验,例如那些涉及用连续时间定义的随机过程的试验,可能需要使用更具有一般性的概率测度。”<br />
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A probability distribution whose sample space is one-dimensional (for example real numbers, list of labels, ordered labels or binary) is called [[Univariate distribution|univariate]], while a distribution whose sample space is a [[vector space]] of dimension 2 or more is called [[Multivariate distribution|multivariate]]. A univariate distribution gives the probabilities of a single [[random variable]] taking on various alternative values; a multivariate distribution (a [[joint probability distribution]]) gives the probabilities of a [[random vector]] – a list of two or more random variables – taking on various combinations of values. Important and commonly encountered univariate probability distributions include the [[binomial distribution]], the [[hypergeometric distribution]], and the [[normal distribution]]. The [[multivariate normal distribution]] is a commonly encountered multivariate distribution.<br />
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A probability distribution whose sample space is one-dimensional (for example real numbers, list of labels, ordered labels or binary) is called univariate, while a distribution whose sample space is a vector space of dimension 2 or more is called multivariate. A univariate distribution gives the probabilities of a single random variable taking on various alternative values; a multivariate distribution (a joint probability distribution) gives the probabilities of a random vector – a list of two or more random variables – taking on various combinations of values. Important and commonly encountered univariate probability distributions include the binomial distribution, the hypergeometric distribution, and the normal distribution. The multivariate normal distribution is a commonly encountered multivariate distribution.<br />
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一个一维的样本空间(例如实数、标签列表、有序标签或二进制)的概率分布被称为'''<font color="#ff8000"> 单变量 Univariate</font>''',而样本空间为二维或更多向量空间的分布被称为'''<font color="#ff8000"> 多变量 Multivariate</font>'''。单变量分布给出了单个随机变量取不同替代值的概率; 联合分布给出了一个随机向量的概率——一个由两个或多个随机变量组成的列表——取值的各种组合。重要的和常见的单变量概率分布包括二项分布、超几何分布和正态分布。多变量正态分布是一种常见的联合分布。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“而样本空间为二维或更多向量空间的分布被称为'''<font color="#ff8000"> 多变量 Multivariate</font>'''”一句中“二维或更多向量空间”改为“二维或更多维向量空间”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“单变量分布给出了单个随机变量取不同替代值的概率”一句中“不同替代值”改为“不同可能值”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“联合分布给出了一个随机向量的概率——一个由两个或多个随机变量组成的列表——取值的各种组合。”一句改为“多变量分布(联合概率分布)给出了一个随机向量(两个或多个随机变量组成的列表)各种取值组合的概率。”<br />
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==Introduction 简介==<br />
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[[File:Dice Distribution (bar).svg|thumb|250px|right|<br />
图1:The [[probability mass function]] (pmf) ''p''(''S'') specifies the probability distribution for the sum ''S'' of counts from two [[dice]]. For example, the figure shows that ''p''(11) = 2/36 = 1/18. The pmf allows the computation of probabilities of events such as ''P''(''S'' > 9) = 1/12 + 1/18 + 1/36 = 1/6, and all other probabilities in the distribution.<br />
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The [[probability mass function (pmf) p(S) specifies the probability distribution for the sum S of counts from two dice. For example, the figure shows that p(11) = 2/36 = 1/18. The pmf allows the computation of probabilities of events such as P(S > 9) = 1/12 + 1/18 + 1/36 = 1/6, and all other probabilities in the distribution.]]<br />
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概率质量函数(pmf) p(s)指定两个骰子计数总和s的概率分布。例如,图中显示 p (11) = 2/36 = 1/18。Pmf 允许计算事件的概率,如 p (s > 9) = 1/12 + 1/18 + 1/36 = 1/6,以及分布中的所有其他概率。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“概率质量函数(pmf) p(s)指定两个骰子计数总和s的概率分布”一句中“指定”改为“列出了”。 <br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“Pmf 允许计算事件的概率”一句中“允许”改为“可用于”。<br />
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To define probability distributions for the simplest cases, it is necessary to distinguish between '''discrete''' and '''continuous''' [[random variable]]s. In the discrete case, it is sufficient to specify a [[probability mass function]] <math>p</math> assigning a probability to each possible outcome: for example, when throwing a fair [[Dice|die]], each of the six values 1 to 6 has the probability 1/6. The probability of an [[Event (probability theory)|event]] is then defined to be the sum of the probabilities of the outcomes that satisfy the event; for example, the probability of the event "the dice rolls an even value" is <br />
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To define probability distributions for the simplest cases, it is necessary to distinguish between discrete and continuous random variables. In the discrete case, it is sufficient to specify a probability mass function p assigning a probability to each possible outcome: for example, when throwing a fair die, each of the six values 1 to 6 has the probability 1/6. The probability of an event is then defined to be the sum of the probabilities of the outcomes that satisfy the event; for example, the probability of the event "the dice rolls an even value" is <br />
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为了定义最简单的概率分布,有必要区分离散和连续的随机变量。在离散情况下,指定一个'''<font color="#ff8000">概率质量函数 Probability Mass Function</font>''' P就足够了,它为每个可能的结果赋予一个概率: 例如,当投掷一个骰子时,6个值中的每一个的概率为1/6。然后将事件的概率定义为满足事件的结果的概率之和; 例如,事件”骰子掷出偶数值”的概率是<br />
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<math>p(2) + p(4) + p(6) = 1/6+1/6+1/6=1/2.</math><br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“6个值中的每一个的概率为1/6”一句中“6个值”改为“1-6这六个值”。<br />
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In contrast, when a random variable takes values from a continuum then typically, any individual outcome has probability zero and only events that include infinitely many outcomes, such as intervals, can have positive probability. For example, the probability that a given object weighs ''exactly'' 500&nbsp;g is zero, because the probability of measuring exactly 500&nbsp;g tends to zero as the accuracy of our measuring instruments increases. Nevertheless, in quality control one might demand that the probability of a "500&nbsp;g" package containing between 490&nbsp;g and 510&nbsp;g should be no less than 98%, and this demand is less sensitive to the accuracy of measurement instruments.<br />
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In contrast, when a random variable takes values from a continuum then typically, any individual outcome has probability zero and only events that include infinitely many outcomes, such as intervals, can have positive probability. For example, the probability that a given object weighs exactly 500&nbsp;g is zero, because the probability of measuring exactly 500&nbsp;g tends to zero as the accuracy of our measuring instruments increases. Nevertheless, in quality control one might demand that the probability of a "500&nbsp;g" package containing between 490&nbsp;g and 510&nbsp;g should be no less than 98%, and this demand is less sensitive to the accuracy of measurement instruments.<br />
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相比之下,当一个随机变量从一个连续体中取值时,那么通常情况下,任何单个结果的概率都为零,只有包含无限多个结果的事件,例如间隔,才有正的概率。例如,一个给定的物体重量正好是500克的概率为零,因为随着我们测量仪器精度的提高,正好测量500克的概率趋向于零。然而,在质量控制方面,人们可能会要求包装在490克至510克之间的“500克”包装的可能性不低于98% ,而这一要求对测量仪器的准确性不太敏感。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“那么通常情况下,任何单个结果的概率都为零,只有包含无限多个结果的事件,例如间隔,才有正的概率”一句改为“通常情况下,任何单个结果的概率都为零,只有包含无限多个结果的事件(例如区间)才有正的概率”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“人们可能会要求包装在490克至510克之间的“500克”包装的可能性不低于98%”一句改为“人们可能会要求介于490克至510克之间的“500克”包装出现的概率不低于98%”。<br />
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Continuous probability distributions can be described in several ways. The [[probability density function]] describes the [[infinitesimal]] probability of any given value, and the probability that the outcome lies in a given interval can be computed by [[Integration (mathematics)|integrating]] the probability density function over that interval. The probability that the possible values lie in some fixed interval can be related to the way sums converge to an integral; therefore, continuous probability is based on the definition of an integral. <br />
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Continuous probability distributions can be described in several ways. The probability density function describes the infinitesimal probability of any given value, and the probability that the outcome lies in a given interval can be computed by integrating the probability density function over that interval. The probability that the possible values lie in some fixed interval can be related to the way sums converge to an integral; therefore, continuous probability is based on the definition of an integral. <br />
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连续概率分布可以用几种方法来描述。'''<font color="#ff8000">概率密度函数 Probability Density Function</font>'''描述了任意给定值的无穷小概率,并且结果在给定区间内的概率可以通过在该区间上积分概率密度函数来计算。可能值位于某一固定区间的概率可以与和收敛于积分的方式有关,因此,连续概率是基于积分的定义。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“并且结果在给定区间内的概率可以通过在该区间上积分概率密度函数来计算。”一句改为“并且结果落在给定区间内的概率可以通过对该区间的概率密度函数进行积分来计算。”<br />
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[[File:Combined Cumulative Distribution Graphs.png|thumb|455x455px|<br />
图2:On the left is the probability density function. On the right is the cumulative distribution function, which is the area under the probability density curve.<br />
左边是概率密度函数。右边是累积分布函数,它是概率密度曲线下面的区域。]]<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图注中“它是概率密度曲线下面的区域”一句中“下面的区域”改为“下方的面积”。<br />
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The [[cumulative distribution function]] describes the probability that the random variable is no larger than a given value; the probability that the outcome lies in a given interval can be computed by taking the difference between the values of the cumulative distribution function at the endpoints of the interval. The cumulative distribution function is the [[antiderivative]] of the probability density function provided that the latter function exists. The cumulative distribution function is the area under the [[probability density function]] from minus infinity <math>\infty</math> to <math>x</math> as described by the picture to the right.<ref>{{Cite book|title=A modern introduction to probability and statistics : understanding why and how|date=2005|publisher=Springer|others=Dekking, Michel, 1946-|isbn=978-1-85233-896-1|location=London|oclc=262680588}}</ref><br />
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The cumulative distribution function describes the probability that the random variable is no larger than a given value; the probability that the outcome lies in a given interval can be computed by taking the difference between the values of the cumulative distribution function at the endpoints of the interval. The cumulative distribution function is the antiderivative of the probability density function provided that the latter function exists. The cumulative distribution function is the area under the probability density function from minus infinity \infty to x as described by the picture to the right.<br />
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累积分布函数指标描述了随机变量不大于给定值的概率; 结果在给定区间内的概率可以通过计算区间终点的累积分布函数差来计算。累积分布函数是概率密度函数的反导函数,前提是后者存在。正如右边图片所描述的那样,累积分布函数是从负无穷到 x 的概率密度函数下面的区域。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“累积分布函数指标描述了随机变量不大于给定值的概率”一句中,删除“指标”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“结果在给定区间内的概率可以通过计算区间终点的累积分布函数差来计算”一句改为“结果落在给定区间内的概率可以通过累积分布函数在区间端点的值之间的差来计算。”<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“累积分布函数是从负无穷到 x 的概率密度函数下面的区域”一句中“下面的区域”改为“下方的面积”。<br />
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[[File:Standard deviation diagram.svg|right|thumb|250px|<br />
图3:The [[probability density function]] (pdf) of the [[normal distribution]], also called Gaussian or "bell curve", the most important continuous random distribution. As notated on the figure, the probabilities of intervals of values correspond to the area under the curve.<br />
正态分布的[概率密度函数(pdf) ,也称为高斯或钟形曲线,是最重要的连续随机分布。如图所示,值间隔的概率对应于曲线下面积。]]<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图注中“也称为高斯或钟形曲线”一句中“高斯”改为“高斯分布”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图注中“值间隔的概率对应于曲线下面积”一句中“值间隔的概率”改为“区间里的值所表示的概率”。<br />
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== Terminology 术语==<br />
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<br />
Some key concepts and terms, widely used in the literature on the topic of probability distributions, are listed below.<ref name=":02" /><br />
<br />
Some key concepts and terms, widely used in the literature on the topic of probability distributions, are listed below. the regions close to the bounds of the random variable, if the pmf or pdf are relatively low therein. Usually has the form X > a, X < b or a union thereof.<br />
<br />
一些关键的,广泛用于以概率分布为主题的文献中的概念和术语,列出如下。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此处英文后半句应位于下文,重复出现。<br />
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=== '''<font color="#ff8000"> Functions for discrete variables 离散变量函数</font>'''===<br />
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Well-known discrete probability distributions used in statistical modeling include the Poisson distribution, the Bernoulli distribution, the binomial distribution, the geometric distribution, and the negative binomial distribution.<br />
<br />
用于统计建模的著名离散概率分布包括泊松分佈、伯努利分布、二项分布、几何分布和负二项分布。<br />
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*'''Probability function''': describes the probability distribution of a discrete random variable.<br />
'''<font color="#ff8000"> 概率函数 Probability Function</font>''':描述离散随机变量的概率分布。<br />
<br />
*'''[[Probability mass function|Probability mass function (pmf)]]:''' function that gives the probability that a discrete random variable is equal to some value.<br />
'''<font color="#ff8000"> 概率质量函数(pmf Probability Mass Function</font>''':给出离散随机变量等于某个值的概率的函数。<br />
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*'''[[Frequency distribution]]''': a table that displays the frequency of various outcomes '''in a sample'''.<br />
'''<font color="#ff8000"> 频率分布 Frequency Distribution</font>''':显示样本中各种结果的频率的表格。<br />
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For a discrete random variable X, let u0, u1, ... be the values it can take with non-zero probability. Denote<br />
<br />
对于一个离散的随机变量 x,设 u0,u1,... 是它在非零概率情况下可以取的值。表示<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句应位于下文,重复出现。<br />
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*'''Relative frequency distribution''': a [[frequency distribution]] where each value has been divided (normalized) by a number of outcomes in a [[Sample (statistics)|sample]] i.e. sample size.<br />
'''<font color="#ff8000"> 相对频率分布 Relative Frequency Distribution</font>''':一种频率分布,其中每个值均已被样本中的多个结果(即样本大小)除(归一化)。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】本句中“多个结果”改为“结果数”。<br />
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*'''Discrete probability distribution function''': general term to indicate the way the total probability of 1 is distributed over '''all''' various possible outcomes (i.e. over entire population) for discrete random variable.<br />
'''<font color="#ff8000">离散概率分布函数 Discrete Probability Distribution Function</font>''':通用术语,表示总概率1在离散随机变量的所有各种可能结果(即整个人群)中的分布方式。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】本句中“整个人群”改为“整个总体”。<br />
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*'''[[Cumulative distribution function]]''': function evaluating the [[probability]] that <math>X</math> will take a value less than or equal to <math>x</math> for a discrete random variable.<br />
'''<font color="#ff8000"> 累积分布函数 Cumulative distribution function</font>''':该函数评估离散随机变量X取小于或等于x的值的概率。<br />
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*'''[[Categorical distribution]]''': for discrete random variables with a finite set of values.<br />
'''<font color="#ff8000"> 分类分布 Categorical Distribution</font>''':适用于具有有限值集的离散随机变量。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】本句中“适用于具有有限值集”改为“取值结果为有限集合”。<br />
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=== '''<font color="#ff8000"> Functions for continuous variables 连续变量函数</font>'''===<br />
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* '''[[Probability density function]] (pdf):''' function whose value at any given sample (or point) in the [[sample space]] (the set of possible values taken by the random variable) can be interpreted as providing a ''relative likelihood'' that the value of the random variable would equal that sample.<br />
'''<font color="#ff8000"> 概率密度函数(pdf)Probability Density function</font>''':可以将其在样本空间中任意给定样本(或点)上的值(随机变量可能获得的一组值)的值解释为提供随机变量值将具有的相对可能性的函数等于那个样本。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句改为“在样本空间(随机变量可能取值的集合)中任意给定样本(或样本点),此样本在该函数上的取值可以被解释成给出了随机变量取值等于此样本的<font color="#ff8000">相对可能性 relative likelihood</font>”。<br />
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It follows that the probability that X takes any value except for u0, u1, ... is zero, and thus one can write X as<br />
<br />
由此可见,除了 u0、 u1、 ... 之外,x 取任何值的概率为零,因此可以将 x 写为<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句应位于下文,重复出现。<br />
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* '''Continuous probability distribution function''': most often reserved for continuous random variables.<br />
'''<font color="#ff8000">连续概率分布函数 Continuous Probability Distribution Function</font>''':最常保留的连续随机变量。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“保留的”改为“用于”。<br />
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* '''[[Cumulative distribution function]]''': function evaluating the [[probability]] that <math>X</math> will take a value less than or equal to <math>x</math> for continuous variable.<br />
'''<font color="#ff8000"> 累积分布函数 Cumulative distribution function</font>''':评估连续变量X取小于或等于x的值的概率的函数。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“评估”改为“计算”;“取小于或等于x的值”改为“取值小于或等于x”。<br />
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===Basic terms 基本术语===<br />
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* [[Mode (statistics)|'''Mode''']]: for a discrete random variable, the value with highest probability; for a continuous random variable, a location at which the probability density function has a local peak.<br />
模式:对于离散随机变量,该值具有最高概率;对于连续随机变量,是概率密度函数具有局部峰值的位置。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“模式”改为“众数”。<br />
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* [[Support (mathematics)|'''Support''']]: set of values that can be assumed, with non-zero probability, by the random variable.<br />
支持:可以由随机变量以非零概率假定的一组值。对于随机变量X,有时表示为R_ {X}<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“支持”改为“支撑集”;“一组值”改为“值的集合”;“有时表示为R_ {X}”改为“它的支撑集有时表示为R_ {X}”。<br />
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* '''Tail''':<ref name='tail'>More information and examples can be found in the articles [[Heavy-tailed distribution]], [[Long-tailed distribution]], [[fat-tailed distribution]]</ref> the regions close to the bounds of the random variable, if the pmf or pdf are relatively low therein. Usually has the form <math>X > a</math>, <math>X < b</math> or a union thereof.<br />
尾巴:如果pmf或pdf相对较低,则靠近随机变量边界的区域。通常形式为X> a,X <b或它们的并集。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句前一半改为“尾部:当pmf或pdf相对较低时,靠近随机变量边界的区域。”<br />
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*'''Head''':<ref name='tail' /> the region where the pmf or pdf is relatively high. Usually has the form <math>a < X < b</math>.<br />
头部:pmf或pdf较高的区域。通常具有a <X <b的形式<br />
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* '''[[Expected value]]''' or '''mean''': the [[weighted average]] of the possible values, using their probabilities as their weights; or the continuous analog thereof.<br />
期望值或均值:可能值的加权平均值,以其概率作为权重;或其连续类似物。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“或其连续类似物”改为“或连续随机变量的类似取值。”<br />
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A continuous probability distribution is a probability distribution whose support is an uncountable set, such as an interval in the real line. They are uniquely characterized by a cumulative density function that can be used to calculate the probability for each subset of the support. There are many examples of continuous probability distributions: normal, uniform, chi-squared, and others.<br />
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一个连续的概率分布是一个支持不可数集的概率分布,比如实数行中的一个区间。它们是唯一拥有属性的一个累积密度函数,可以用来计算支持的每个子集的概率。有许多连续概率分布的例子: 正态、均匀、卡方等等。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此段应出现在下文,此处重复。<br />
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*'''[[Median]]''': the value such that the set of values less than the median, and the set greater than the median, each have probabilities no greater than one-half.<br />
中位数:这样的值,即一组值小于中位数,而该组大于中位数,每一个的概率不大于二分之一。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句改为“中位数:此值使得小于中位数的取值集合和大于中位数的取值集合各自的概率都不大于二分之一。”<br />
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*'''[[Variance]]''': the second moment of the pmf or pdf about the mean; an important measure of the [[Statistical dispersion|dispersion]] of the distribution.<br />
方差:关于均值的pmf或pdf的第二矩;分布的重要指标。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句改为“方差:关于均值的pmf或pdf的二阶矩;度量分布离散性的重要指标。”<br />
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* '''[[Standard deviation]]''': the square root of the variance, and hence another measure of dispersion.<br />
标准偏差:方差的平方根,因此是色散的另一种度量。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句改为“标准差:方差的平方根,因此是度量离散程度的另一指标。”<br />
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* [[Symmetric probability distribution|'''Symmetry''']]: a property of some distributions in which the portion of the distribution to the left of a specific value(usually the median) is a mirror image of the portion to its right.<br />
对称性:某些分布的一种属性,其中特定值左侧(通常是中位数)的分布部分是其右侧部分的镜像。<br />
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*'''[[Skewness]]''': a measure of the extent to which a pmf or pdf "leans" to one side of its mean. The third [[standardized moment]] of the distribution.<br />
偏度:衡量pmf或pdf在其均值的一侧“倾斜”的程度。分布的第三个标准化时刻。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句“分布的第三个标准化时刻”改为“分布的三阶矩”。<br />
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*'''[[Kurtosis]]''': a measure of the "fatness" of the tails of a pmf or pdf. The fourth standardized moment of the distribution.<br />
峰度:pmf或pdf尾部“脂肪”的量度。分布的第四个标准化时刻。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句改为“峰度:pmf或pdf尾部“胖瘦”的量度。分布的四阶矩。”。<br />
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=='''<font color="#ff8000"> Discrete probability distribution 离散概率分布</font>'''==<br />
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[[File:Discrete probability distrib.svg|right|thumb|<br />
图4:The probability mass function of a discrete probability distribution. The probabilities of the [[Singleton (mathematics)|singleton]]s {1}, {3}, and {7} are respectively 0.2, 0.5, 0.3. A set not containing any of these points has probability zero.]]<br />
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[[File:Discrete probability distribution.svg|right|thumb|<br />
图5:The [[cumulative distribution function|cdf]] of a discrete probability distribution, ...离散概率分布]]<br />
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[[File:Normal probability distribution.svg|right|thumb|<br />
图6:... of a continuous probability distribution, ...连续概率分布]]<br />
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[[File:Mixed probability distribution.svg|right|thumb|<br />
图7:... of a distribution which has both a continuous part and a discrete part.既有连续部分又有离散部分]]<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图4图注未译,应为“离散概率分布的概率质量函数。单元集{1}, {3}, 和{7}的概率分别为0.2, 0.5, 0.3。不包含这些点的集合的概率是0。”。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图5图注改为“离散概率分布的累积分布函数”。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图6图注改为“连续概率分布的累积分布函数”。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】图7图注改为“既有连续部分又有离散部分的分布的累积分布函数”。<br />
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A '''discrete probability distribution''' is a probability distribution that can take on a countable number of values.<ref>{{Cite book|title=Probability and stochastics|last=Erhan|first=Çınlar|date=2011|publisher=Springer|isbn=9780387878591|location=New York|pages=51|oclc=710149819}}</ref> For the probabilities to add up to 1, they have to decline to zero fast enough. For example, if <math>\operatorname{P}(X=n) = \tfrac{1}{2^n}</math> for ''n'' = 1, 2, ..., the sum of probabilities would be 1/2 + 1/4 + 1/8 + ... = 1.<br />
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离散概率分布是可以具有可数数量的值的概率分布。在值的范围是无限大的情况下,这些值必须足够快地下降到零,以使概率加起来为1。例如,如果<math>\operatorname{P}(X=n) = \tfrac{1}{2^n}</math> for ''n'' = 1, 2,概率之和为1/2 + 1/4 + 1/8 + ... = 1。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“在值的范围是无限大的情况下,这些值必须足够快地下降到零,以使概率加起来为1”一句中“无限大”改为“可数无穷大”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】含公式句中“如果<math>\operatorname{P}(X=n) = \tfrac{1}{2^n}</math> for ''n'' = 1, 2”改为“如果对于''n'' = 1, 2, ...有<math>\operatorname{P}(X=n) = \tfrac{1}{2^n}</math>”。<br />
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Well-known discrete probability distributions used in statistical modeling include the [[Poisson distribution]], the [[Bernoulli distribution]], the [[binomial distribution]], the [[geometric distribution]], and the [[negative binomial distribution]].<ref name=":1" /> Additionally, the [[Uniform distribution (discrete)|discrete uniform distribution]] is commonly used in computer programs that make equal-probability random selections between a number of choices.<br />
统计建模中使用的众所周知的离散概率分布包括泊松分布,伯努利分布,二项式分布,几何分布和负二项式分布。[3]此外,离散均匀分布通常用于在多个选择之间进行等概率随机选择的计算机程序中。<br />
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--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“统计建模中使用的众所周知的离散概率分布包括”中“使用的众所周知的”改为“常用的”。<br />
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When a [[Sample (statistics)|sample]] (a set of observations) is drawn from a larger population, the sample points have an [[empirical distribution function|empirical distribution]] that is discrete and that provides information about the population distribution.<br />
当从更大的总体中抽取一个样本(一组观察值)时,这些采样点的经验分布是离散的,并且提供了有关总体分布的信息。<br />
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===Measure theoretic formulation 测量理论公式===<br />
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A [[measurable function]] <math>X \colon A \to B </math> between a [[probability space]] <math>(A, \mathcal A, P)</math> and a [[measurable space]] <math>(B, \mathcal B) </math> is called a '''discrete random variable''' provided that its image is a countable set. In this case measurability of <math>X</math> means that the pre-images of singleton sets are measurable, i.e., <math>X^{-1}(\{b\}) \in \mathcal A</math> for all <math>b \in B</math>.<br />
The latter requirement induces a [[probability mass function]] <math>f_X \colon X(A) \to \mathbb R</math> via <math> f_X(b):=P(X^{-1}(\{b\}))</math>. Since the pre-images of disjoint sets<br />
are disjoint,<br />
:<math>\sum_{b \in X(A)} f_X(b) = \sum_{b \in X(A)} P(X^{-1} (\{b\})) = P \left( \bigcup_{b \in X(A)} X^{-1}(\{b\}) \right) = P(A)=1.</math><br />
This recovers the definition given above.<br />
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一个可测量的函数 <math>X \colon A \to B </math> 在一个概率空间中 <math>(A, \mathcal A, P)</math> and 和一个可测量空间 <math>(B, \mathcal B) </math> 被叫做离散随机变量。该图像是一个可数的集合。在这种情况下<math>X</math>的测量意味着单例集的原像是可测量的 i.e., <math>X^{-1}(\{b\}) \in \mathcal A</math> 对于所有的<math>b \in B</math>.<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“一个可测量的函数 <math>X \colon A \to B </math> 在一个概率空间中 <math>(A, \mathcal A, P)</math> and 和一个可测量空间 <math>(B, \mathcal B) </math> 被叫做离散随机变量。该图像是一个可数的集合。”一句改为“在概率空间<math>(A, \mathcal A, P)</math> 和可测空间之间的一个可测函数 <math>X \colon A \to B </math>称为离散随机变量,它的像是一个可数集合。”<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“在这种情况下<math>X</math>的测量意味着单例集的原像是可测量的 i.e., <math>X^{-1}(\{b\}) \in \mathcal A</math> 对于所有的<math>b \in B</math>.”一句改为“在这种情况下<math>X</math>的可测量性意味着单元集的原像是可测量的,即对于所有的<math>b \in B</math>,有 <math>X^{-1}(\{b\}) \in \mathcal A</math> 。”<br />
<br />
后者需要包括概率质量函数 <math>f_X \colon X(A) \to \mathbb R</math> via <math> f_X(b):=P(X^{-1}(\{b\}))</math>. 由于不相交集的原像不相交<br />
:<math>\sum_{b \in X(A)} f_X(b) = \sum_{b \in X(A)} P(X^{-1} (\{b\})) = P \left( \bigcup_{b \in X(A)} X^{-1}(\{b\}) \right) = P(A)=1.</math><br />
这包含了上面所提到的定义<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句中“后者需要”改为“后一个必要条件”。<br />
<br />
==='''<font color="#ff8000"> 累积分布函数 Cumulative distribution function</font>'''===<br />
<br />
Equivalently to the above, a discrete random variable can be defined as a random variable whose [[cumulative distribution function]] (cdf) increases only by [[jump discontinuity|jump discontinuities]]—that is, its cdf increases only where it "jumps" to a higher value, and is constant between those jumps. Note however that the points where the cdf jumps may form a dense set of the real numbers. The points where jumps occur are precisely the values which the random variable may take.<br />
<br />
与上述等效,可以将离散随机变量定义为其累积分布函数(cdf)仅因跳跃不连续性而增加的随机变量,也就是说,其cdf仅在“跳跃”至较高值时才增加,并且在那些跳跃点间是常数。但是请注意,cdf跳转的点可能会形成密集的实数集。发生跳变的点恰好是随机变量可能取的值。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】此句中“密集的实数集”改为“实数的稠密集”。<br />
<br />
===Delta-function representation 三角函数表示===<br />
<br />
Consequently, a discrete probability distribution is often represented as a generalized [[probability density function]] involving [[Dirac delta function]]s, which substantially unifies the treatment of continuous and discrete distributions. This is especially useful when dealing with probability distributions involving both a continuous and a discrete part.<ref>{{Cite journal|last=Khuri|first=André I.|date=March 2004|title=Applications of Dirac's delta function in statistics|journal=International Journal of Mathematical Education in Science and Technology|language=en|volume=35|issue=2|pages=185–195|doi=10.1080/00207390310001638313|issn=0020-739X}}</ref><br />
<br />
因此,离散概率分布通常表示为涉及Dirac delta函数的广义概率密度函数,该函数实质上统一了对连续分布和离散分布的处理。当处理涉及连续和离散部分的概率分布时,这特别有用。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】标题“三角函数表示”改为“&delta函数表示”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“离散概率分布通常表示为涉及Dirac delta函数的广义概率密度函数”改为“离散概率分布通常表示为包含狄拉克&delta函数的广义概率密度函数”。<br />
<br />
===Indicator-function representation 指标功能表示===<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】标题“指标功能表示”改为“指示函数表示”。<br />
For a discrete random variable ''X'', let ''u''<sub>0</sub>, ''u''<sub>1</sub>, ... be the values it can take with non-zero probability. Denote<br />
对于离散随机变量X,令u0,u1,...是它可以以非零概率获取的值。表示<br />
:<math>\Omega_i=X^{-1}(u_i)= \{\omega: X(\omega)=u_i\},\, i=0, 1, 2, \dots</math><br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】标题“表示”改为“令”。<br />
这些是不相交的集合,对于这样的集合:<br />
<br />
:<math>P\left(\bigcup_i \Omega_i\right)=\sum_i P(\Omega_i)=\sum_i P(X=u_i)=1.</math><br />
<br />
因此,X取u0,u1,...以外的任何值的概率为零,因此可以将X写入为<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】标题“写入为”改为“写为”。<br />
<br />
:<math>X(\omega)=\sum_i u_i 1_{\Omega_i}(\omega)</math><br />
<br />
except on a set of probability zero, where <math>1_A</math> is the [[indicator function]] of ''A''. This may serve as an alternative definition of discrete random variables.<br />
除了概率为零的集合外,其中1_ {A}是A的指标函数。这可以用作离散随机变量的替代定义。<br />
<br />
==Continuous probability distribution 连续概率分布==<br />
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{{See also|Probability density function}}<br />
<br />
<br />
<br />
A '''continuous probability distribution''' is a probability distribution whose support is an uncountable set, such as an interval in the real line.<ref>{{Cite book|title=Introduction to probability models|author1=Sheldon M. Ross|date=2010|publisher=Elsevier}}</ref> They are uniquely characterized by a [[cumulative density function]]{{dn|date=August 2020}} that can be used to calculate the probability for each subset of the support. There are many examples of continuous probability distributions: [[normal distribution|normal]], [[Uniform distribution (continuous)|uniform]], [[Chi-squared distribution|chi-squared]], and [[List of probability distributions#Continuous distributions|others]].<br />
连续概率分布是一种概率分布,其支持是不可计数的集合,例如实线中的间隔。它们的独特之处在于可用于计算支撑的每个子集的概率的累积密度函数[需要消除歧义]。连续概率分布有很多示例:正态分布,均匀分布,卡方分布和其他分布。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“连续概率分布是一种概率分布,其支持是不可计数的集合,例如实线中的间隔。”一句改为“连续概率分布是支撑集为不可数集的概率分布,如实数轴上的区间。”<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“它们的独特之处在于可用于计算支撑的每个子集的概率的累积密度函数[需要消除歧义]”一句中,“支撑的每个子集”改为“支撑集每个子集”。<br />
<br />
A random variable <math>X</math> has a continuous probability distribution if there is a function <math>f: \mathbb{R} \rightarrow [0, \infty)</math> such that for each interval <math>I \subset \mathbb{R}</math> the probability of <math>X</math> belonging to <math>I</math> is given by the integral of <math>f</math> over <math>I</math>.<ref>Chapter 3.2 of {{harvp|DeGroot, Morris H.|Schervish, Mark J.|2002}}</ref> For example, if <math>I = [a, b]</math> then we would have:<br />
<br />
:<math>\operatorname{P}\left[a \le X \le b\right] = \int_a^b f(x) \, dx</math><br />
<br />
一个随机变量<math>X</math> 有一个连续的概率分布,如果这有一个函数<math>f: \mathbb{R} \rightarrow [0, \infty)</math> 对于每一个区间<math>I \subset \mathbb{R}</math> <math>I</math>的概率 <math>X</math>是<math>f</math> 在 <math>I</math>上的积分.<ref>Chapter 3.2 of {{harvp|DeGroot, Morris H.|Schervish, Mark J.|2002}}</ref> 例如, 如果<math>I = [a, b]</math> 可得到:<br />
<br />
:<math>\operatorname{P}\left[a \le X \le b\right] = \int_a^b f(x) \, dx</math><br />
<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“例如”前一句中,将“如果”以后内容作为前半句,“对于”前加“使得”二字,“<math>I \subset \mathbb{R}</math>”后加逗号,“<math>I</math>的概率 <math>X</math>”改为“随机变量 <math>X</math>属于<math>I</math>的概率”,“一个随机变量<math>X</math> 有一个连续的概率分布”改为“则称这个随机变量<math>X</math> 有一个连续的概率分布”并置于后半句。<br />
<br />
In particular, the probability for <math>X</math> to take any single value <math>a</math> (that is <math>a \le X \le a</math>) is zero, because an [[integral]] with coinciding upper and lower limits is always equal to zero. A variable that satisfies the above is called '''continuous random variable'''. Its cumulative density function is defined as<br />
<br />
:<math>F(x) = \operatorname{P}\left[-\infty < X \le x\right] = \int_{-\infty}^x f(x) \, dx</math><br />
<br />
特别是,X取任何单个值a(即a≤X≤a)的概率为零,因为上下限一致的积分始终等于零。满足上述条件的变量称为连续随机变量。其累积密度函数定义为<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“特别是”改为“特别地”,“其累积密度函数定义为”下面应有上方那行公式。<br />
<br />
which, by this definition, has the properties:<br />
根据定义有以下一些性质<br />
<br />
<ul><br />
<br />
<li style="margin: 0.7rem 0;"><math>F(x)</math> is non-decreasing;</li><br />
<br />
<li style="margin: 0.7rem 0;"><math>0 \le F(x) \le 1</math>;</li><br />
<br />
<li style="margin: 0.7rem 0;"><math>\lim_{x \rightarrow -\infty} F(x) = 0</math> and <math>\lim_{x \rightarrow \infty} F(x) = 1</math>;</li><br />
<br />
<li style="margin: 0.7rem 0;"><math>P(a \le X < b) = F(b) - F(a)</math>; and</li><br />
<br />
<li style="margin: 0.7rem 0;"><math>F(x)</math> is continuous (due to the [[Riemann integral]] properties).</li><br />
<br />
</ul><br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】以上性质没有翻译。第一行应为“<math>F(x)</math>是非减的”;第三行"and"改为“和”;第四行"and"改为“以及”;第五行应为“由于黎曼积分的性质,<math>F(x)</math>连续”<br />
<br />
It is also possible to think in the opposite direction, which allows more flexibility. Say <math>F(x)</math> is a function that satisfies all but the last of the properties above, then <math>F</math> represents the cumulative density function for some random variable: a discrete random variable if <math>F</math> is a step function, and a continuous random variable otherwise.<ref>See Theorem 2.1 of {{harvp|Vapnik|1998}}, or [[Lebesgue's decomposition theorem]]. The section [[#Delta-function_representation]] may also be of interest.</ref> This allows for continuous distributions that has a cumulative density function, but not a probability density function, such as the [[Cantor distribution]].<br />
也可以朝相反的方向思考,这样可以有更大的灵活性。假设 f(x)是满足上述所有性质的函数,那么 f 表示某个随机变量的累积密度函数: 如果 f 是阶跃函数,则为离散随机变量,否则为连续随机变量。这允许具有累积密度函数的连续分布,而不是概率密度函数分布,例如 Cantor 分布。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“假设 f(x)是满足上述所有性质的函数”改为“假设 f(x)是满足上述除最后一条外其他所有性质的函数”,“那么 f 表示某个随机变量的累积密度函数”中“某个”改为“某种”。“这允许具有累积密度函数的连续分布,而不是概率密度函数分布,例如 Cantor 分布”改为“这允许连续分布有累积密度函数但无概率密度函数,如康托分布”。<br />
<br />
<br />
It is often necessary to generalize the above definition for more arbitrary subsets of the real line. In these contexts, a continuous probability distribution is defined as a probability distribution with a cumulative distribution function that is [[absolute continuity|absolutely continuous]]. Equivalently, it is a probability distribution on the [[real numbers]] that is [[absolute continuity|absolutely continuous]] with respect to the [[Lebesgue measure]]. Such distributions can be represented by their [[probability density function]]s. If <math>X</math> is such an absolutely continuous random variable, then it has a [[probability density function]] <math>f(x)</math>, and its probability of falling into a Lebesgue-measurable set <math>A \subset \mathbb{R}</math> is:<br />
<br />
:<math>\operatorname{P}\left[X \in A\right] = \int_A f(x) \, d\mu</math><br />
<br />
where <math>\mu</math> is the Lebesgue measure.<br />
<br />
对于实线的更多任意子集,通常有必要对上述定义进行概括。在这些情况下,连续概率分布定义为具有绝对连续的累积分布函数的概率分布。等效地,就Lebesgue测度而言,它是实数上的概率分布,它是绝对连续的。这样的分布可以用它们的概率密度函数表示。如果X是这样一个绝对连续的随机变量,则它具有概率密度函数f(x),并且落入Lebesgue可测量集合A⊂R的概率为:<br />
<br />
:<math>\operatorname{P}\left[X \in A\right] = \int_A f(x) \, d\mu</math><br />
<br />
这里,mu是Lebesgue度量<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“对于实线的更多任意子集,通常有必要对上述定义进行概括”中“实线”改为“实数轴”。“那么 f 表示某个随机变量的累积密度函数”中“某个”改为“某种”。“这允许具有累积密度函数的连续分布,而不是概率密度函数分布,例如 Cantor 分布”改为“这允许连续分布有累积密度函数但无概率密度函数,如康托分布”。<br />
<br />
<br />
Note on terminology: some authors use the term "continuous distribution" to denote distributions whose cumulative distribution functions are [[continuous function|continuous]], rather than [[absolute continuity|absolutely continuous]]. These distributions are the ones <math>\mu</math> such that <math>\mu\{x\}\,=\,0</math> for all <math>\,x</math>. This definition includes the (absolutely) continuous distributions defined above, but it also includes [[singular distribution]]s, which are neither absolutely continuous nor discrete nor a mixture of those, and do not have a density. An example is given by the [[Cantor distribution]].<br />
<br />
关于术语的注释:一些作者使用术语“连续分布”来表示其累积分布函数是连续的而不是绝对连续的分布。这些分布是所有x的μ{x} = 0的μ分布。该定义包括上面定义的(绝对)连续分布,但也包括奇异分布,既不是绝对连续也不是离散的,也不是它们的混合。没有密度。 Cantor分布给出了一个示例。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“既不是绝对连续也不是离散的,也不是它们的混合。没有密度。”改为“这种奇异分布既不是绝对连续,也不是离散的,也不是它们的混合,同时也没有密度。”<br />
<br />
== '''<font color="#ff8000"> [[Andrey Kolmogorov|Kolmogorov]] definition 柯尔莫哥洛夫的定义</font>'''==<br />
<br />
{{Main|Probability space|Probability measure}}<br />
<br />
<br />
<br />
In the [[measure theory|measure-theoretic]] formalization of [[probability theory]], a [[random variable]] is defined as a [[measurable function]] <math>X</math> from a [[probability space]] <math>(\Omega, \mathcal{F}, \mathbb{P})</math> to a [[measurable space]] <math>(\mathcal{X},\mathcal{A})</math>. Given that probabilities of events of the form <math>\{\omega\in\Omega\mid X(\omega)\in A\}</math> satisfy [[Probability axioms|Kolmogorov's probability axioms]], the '''probability distribution of ''X''''' is the [[pushforward measure]] <math>X_*\mathbb{P}</math> of <math>X</math> , which is a [[probability measure]] on <math>(\mathcal{X},\mathcal{A})</math> satisfying <math>X_*\mathbb{P} = \mathbb{P}X^{-1}</math>.<ref>{{Cite book|title=Probability theory : an analytic view|last=W.|first=Stroock, Daniel|date=1999|publisher=Cambridge University Press|isbn=978-0521663496|edition= Rev.|location=Cambridge [England]|pages=11|oclc=43953136}}</ref><ref>{{Cite book|title=Foundations of the theory of probability|last=Kolmogorov|first=Andrey|publisher=Chelsea Publishing Company|year=1950|isbn=|location=New York, USA|pages=21–24|orig-year=1933}}</ref><ref>{{Cite web|url=https://mathcs.clarku.edu/~djoyce/ma217/axioms.pdf|title=Axioms of Probability|last=Joyce|first=David|date=2014|website=Clark University|url-status=live|archive-url=|archive-date=|access-date=December 5, 2019}}</ref><br />
<br />
在概率论的度量理论形式化中,将随机变量定义为可测量函数概率空间中的X(Ω,F,P)到一个可测量的空间(X,A)。给定{ω∈Ω∣X(ω)∈A}形式的事件的概率。满足Kolmogorov的概率公理,X的概率分布为X的前推量度X * P,它是满足<math>X_*\mathbb{P} = \mathbb{P}X^{-1}</math>的概率量度<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“在概率论的度量理论形式化中”一句中“度量理论”改为“测度论”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“将随机变量定义为可测量函数概率空间中的X(Ω,F,P)到一个可测量的空间(X,A)”一句改为“随机变量定义为从概率空间<math>(\Omega, \mathcal{F}, \mathbb{P})</math>到测度空间<math>(\mathcal{X},\mathcal{A})</math>的测度函数<math>(\mathcal{X},\mathcal{A})</math>。”<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“给定{ω∈Ω∣X(ω)∈A}形式的事件的概率。满足Kolmogorov的概率公理,X的概率分布为X的前推量度X * P”一句改为“假设这种形式的事件概率<math>\{\omega\in\Omega\mid X(\omega)\in A\}</math>满足满足柯尔莫哥洛夫的概率公理,则X的概率分布为X的pushforward measure<math>X_*\mathbb{P}</math>”。<br />
<br />
==Random number generation 随机数生成==<br />
{{Main|Pseudo-random number sampling}}<br />
<br />
Most algorithms are based on a [[pseudorandom number generator]] that produces numbers ''X'' that are uniformly distributed in the [[half-open interval]] [0,1). These [[random variate]]s ''X'' are then transformed via some algorithm to create a new random variate having the required probability distribution. With this source of uniform pseudo-randomness, realizations of any random variable can be generated.<ref name=":0">{{Citation|last1=Dekking|first1=Frederik Michel|title=Why probability and statistics?|date=2005|work=A Modern Introduction to Probability and Statistics|pages=1–11|publisher=Springer London|isbn=978-1-85233-896-1|last2=Kraaikamp|first2=Cornelis|last3=Lopuhaä|first3=Hendrik Paul|last4=Meester|first4=Ludolf Erwin|doi=10.1007/1-84628-168-7_1}}</ref><br />
<br />
大多数算法基于'''<font color="#ff8000"> 伪随机数生成器 Pseudorandom Number Generator</font>''',该伪随机数生成器生成在半开间隔[0,1)中均匀分布的数字X。然后,通过某种算法对这些随机变量X进行转换,以创建具有所需概率分布的新随机变量。利用这种统一的伪随机源,可以生成任何随机变量的实现。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“半开间隔”改为“半开区间”。<br />
<br />
For example, suppose <math>U</math> has a uniform distribution between 0 and 1. To construct a random Bernoulli variable for some <math>0 < p < 1</math>, we define<br />
<br />
<math>{\displaystyle X ={\begin{cases}1,&{\mbox{if }}U<p\\0,&{\mbox{if }}U\geq p\end{cases}}}<br />
</math><br />
<br />
so that<br />
<br />
<math>\textrm{P}(X=1) = \textrm{P}(U<p) = p,<br />
\textrm{P}(X=0) = \textrm{P}(U\geq p) = 1-p.</math><br />
<br />
例如,假设U具有介于0和1之间的均匀分布。为某些对象构造一个随机的Bernoulli变量0 <p <1,我们定义<br />
<br />
<math>{\displaystyle X ={\begin{cases}1,&{\mbox{if }}U<p\\0,&{\mbox{if }}U\geq p\end{cases}}}<br />
</math><br />
<br />
因此<br />
<br />
<math>\textrm{P}(X=1) = \textrm{P}(U<p) = p,<br />
\textrm{P}(X=0) = \textrm{P}(U\geq p) = 1-p.</math><br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“因此”改为“使得”。<br />
<br />
This random variable X has a Bernoulli distribution with parameter <math>p</math>.<ref name=":0"/> Note that this is a transformation of discrete random variable.<br />
该随机变量X具有参数的伯努利分布p。请注意,这是离散随机变量的变换。<br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“该随机变量X具有参数的伯努利分布p”改为“该随机变量X具有以p为参数的伯努利分布”。<br />
<br />
For a distribution function <math>F</math> of a continuous random variable, a continuous random variable must be constructed. <math>F^{inv}</math>, an inverse function of <math>F</math>, relates to the uniform variable <math>U</math>:<br />
<br />
<math>{U\leq F(x)} = {F^{inv}(U)\leq x}.</math><br />
<br />
F或连续随机变量的分布函数F,必须构造连续随机变量。 <math>F^{inv}</math>,F的反函数,涉及均匀变量U:<br />
<math>{U\leq F(x)} = {F^{inv}(U)\leq x}.</math><br />
<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“F或连续随机变量的分布函数F”中“F或”改为“对于”。<br />
--[[用户:普天星相|普天星相]]([[用户讨论:普天星相|讨论]]) 【审校】“F的反函数,涉及均匀变量U”改为“F反函数<math>F^{inv}</math>与均匀变量U有以下关系:”。<br />
<br />
For example, suppose a random variable that has an exponential distribution <math>F(x) = 1 - e^{-\lambda x}</math> must be constructed.<br />
例如,假设必须构造一个具有指数分布<math>F(x) = 1 - e^{-\lambda x}</math> 的随机变量。<br />
<br />
<math>\begin{align}<br />
F(x) = u &\Leftrightarrow 1-e^{-\lambda x} = u \\ &\Leftrightarrow e^{-\lambda x } = 1-u \\&\Leftrightarrow -\lambda x = \ln(1-u) \\ &\Leftrightarrow x = \frac{-1}{\lambda}\ln(1-u)<br />
\end{align}</math><br />
<br />
所以<math>F^{inv}(u) = \frac{-1}{\lambda}\ln(1-u)</math> 并且如果 <math>U</math> 有一个<math>U(0,1)</math> 分布, 然后随机变量 <math>X</math> 被定义为 <math>X = F^{inv}(U) = \frac{-1}{\lambda} \ln(1-U)</math>. 这里有一个指数分布 <math>\lambda</math>.<ref name=":0" /><br />
<br />
A frequent problem in statistical simulations (the [[Monte Carlo method]]) is the generation of [[Pseudorandomness|pseudo-random numbers]] that are distributed in a given way.<br />
统计模拟(蒙特卡洛方法)中经常遇到的一个问题是生成以给定方式分布的伪随机数。<br />
<br />
== Common probability distributions and their applications 共同概率分布及其应用==<br />
{{Main list|List of probability distributions}}<br />
<br />
The concept of the probability distribution and the random variables which they describe underlies the mathematical discipline of probability theory, and the science of statistics. There is spread or variability in almost any value that can be measured in a population (e.g. height of people, durability of a metal, sales growth, traffic flow, etc.); almost all measurements are made with some intrinsic error; in physics, many processes are described probabilistically, from the [[Kinetic theory of gases|kinetic properties of gases]] to the [[quantum mechanical]] description of [[fundamental particles]]. For these and many other reasons, simple [[number]]s are often inadequate for describing a quantity, while probability distributions are often more appropriate.<br />
<br />
概率分布和内蕴其中的随机变量的概念是概率论和统计学领域的基础。几乎任何可以在群体中测量的值都存在价差或可变性(例如人的身高,金属的耐用性,销售增长,交通流量等);几乎所有测量都存在一定的固有误差;在物理学中,从气体动力学理论到基本粒子的量子力学描述都用概率论来描述。出于各种原因,简单数字通常很难表述一个量量,而用概率分布表述通常更合适。<br />
<br />
The following is a list of some of the most common probability distributions, grouped by the type of process that they are related to. For a more complete list, see [[list of probability distributions]], which groups by the nature of the outcome being considered (discrete, continuous, multivariate, etc.)<br />
以下列出了一些最常见的概率分布,按与之相关的过程类型进行分组。更完整的内容请参见概率分布列表,该列表按研究对象的性质(离散,连续,多元等)进行分组。<br />
<br />
All of the univariate distributions below are singly peaked; that is, it is assumed that the values cluster around a single point. In practice, actually observed quantities may cluster around multiple values. Such quantities can be modeled using a [[mixture distribution]].<br />
下面所有的单变量分布都是单峰的。也就是说,假设值聚集在单个值周围。实际上,实际观测量可能会聚集在多个值附近,可以使用混合分布对这种量进行建模。<br />
<br />
=== '''<font color="#ff8000">Linear growth (e.g. errors, offsets) 线性增长 </font>'''===<br />
<br />
* [[Normal distribution]] (Gaussian distribution), for a single such quantity; the most commonly used continuous distribution<br />
'''<font color="#ff8000"> 正态分布(高斯分布 Normal Distribution</font>''',适用于单个变量;是最常用的连续分布<br />
<br />
=== '''<font color="#ff8000"> Exponential growth (e.g. prices, incomes, populations) 指数增长</font>'''===<br />
<br />
* [[Log-normal distribution]], for a single such quantity whose log is [[Normal distribution|normally]] distributed<br />
'''<font color="#ff8000">对数正态分布 Log-normal Distribution</font>''',适用于对数为正态分布的单个变量<br />
<br />
* [[Pareto distribution]], for a single such quantity whose log is [[Exponential distribution|exponentially]] distributed; the prototypical [[power law]] distribution<br />
'''<font color="#ff8000">帕累托分布 Pareto Distribution</font>''',适用于指数为正态分布的单个变量;是幂律分布的原型<br />
<br />
=== '''<font color="#ff8000"> Uniformly distributed quantities 数量均匀分布</font>'''===<br />
<br />
* [[Discrete uniform distribution]], for a finite set of values (e.g. the outcome of a fair die)<br />
'''<font color="#ff8000"> 离散均匀分布 Discrete Uniform Distributed</font>''',用于有限的一组值(例如,均匀骰子的结果)<br />
<br />
* [[Continuous uniform distribution]], for continuously distributed values<br />
'''<font color="#ff8000">连续均匀分布 Continuous Uniform Distributed</font>''',用于连续分布的值<br />
<br />
=== Bernoulli trials (yes/no events, with a given probability) 伯努利试验(给定的概率的是或否事件===<br />
<br />
* Basic distributions 基本分布:<br />
** [[Bernoulli distribution]], for the outcome of a single Bernoulli trial (e.g. success/failure, yes/no)<br />
'''<font color="#ff8000"> 伯努利分布 Bernoulli Distribution</font>''',用于描述单个伯努利试验的结果(例如成功/失败,是/否)<br />
<br />
** [[Binomial distribution]], for the number of "positive occurrences" (e.g. successes, yes votes, etc.) given a fixed total number of [[Independent (statistics)|independent]] occurrences<br />
'''<font color="#ff8000">二项式分布 Binomial Distribution </font>''',用于描述给定总数的前提下相互独立变量的成功次数(例如,成功,赞成票等)<br />
<br />
** [[Negative binomial distribution]], for binomial-type observations but where the quantity of interest is the number of failures before a given number of successes occurs<br />
'''<font color="#ff8000">负二项分布 Negative Binomial Distribution</font>''',用于二项式观察,但是关注的数量是在给定成功次数之前发生的失败次数<br />
<br />
** [[Geometric distribution]], for binomial-type observations but where the quantity of interest is the number of failures before the first success; a special case of the [[negative binomial distribution]]<br />
'''<font color="#ff8000">几何分布 Geometric Distribution</font>''',用于二项式观测,但是关注的数量是首次成功之前的失败数量;是负二项分布的特殊情况<br />
<br />
* Related to sampling schemes over a finite population 与有限人口抽样方案有关:<br />
<br />
** [[Hypergeometric distribution]], for the number of "positive occurrences" (e.g. successes, yes votes, etc.) given a fixed number of total occurrences, using [[sampling without replacement]]<br />
'''<font color="#ff8000"> 超几何分布 Hypergeometric Distribution</font>''',描述“成功”的次数(例如成功,赞成票等),给定了一定的总出现数量,使用采样而无需替换<br />
<br />
** [[Beta-binomial distribution]], for the number of "positive occurrences" (e.g. successes, yes votes, etc.) given a fixed number of total occurrences, sampling using a [[Pólya urn model]] (in some sense, the "opposite" of [[sampling without replacement]])<br />
'''<font color="#ff8000"> 贝塔二项式分布 Beta-binomial Distribution</font>''',对于给定的总发生次数为“阳性”的次数(例如,成功,赞成票等),使用Pólyaurn模型进行采样(在某种意义上,为“替代”而不进行替换) )<br />
<br />
=== Categorical outcomes (events with ''K'' possible outcomes, with a given probability for each outcome) 分类结果(具有K个可能结果的事件,每个结果具有给定的概率)===<br />
<br />
* [[Categorical distribution]], for a single categorical outcome (e.g. yes/no/maybe in a survey); a generalization of the [[Bernoulli distribution]]<br />
针对单个分类结果的'''<font color="#ff8000">分类分布 Categorical Distribution</font>'''(例如,调查中的是/否/也许);伯努利分布的一般化<br />
<br />
* [[Multinomial distribution]], for the number of each type of categorical outcome, given a fixed number of total outcomes; a generalization of the [[binomial distribution]]<br />
给定总结果的固定数量,针对每种类别结果的数量的'''<font color="#ff8000">多项式分布 Multinomial Distribution</font>''';二项式分布的一般化<br />
<br />
* [[Multivariate hypergeometric distribution]], similar to the [[multinomial distribution]], but using [[sampling without replacement]]; a generalization of the [[hypergeometric distribution]]<br />
'''<font color="#ff8000">多元超几何分布 Multivariate Distribution</font>''',类似于多项式分布,但使用采样而不进行替换;超几何分布的一般化<br />
<br />
=== Poisson process (events that occur independently with a given rate) 泊松过程(以给定速率独立发生的事件)===<br />
<br />
* [[Poisson distribution]], for the number of occurrences of a Poisson-type event in a given period of time<br />
'''<font color="#ff8000"> 泊松分布 Poisson Distribution</font>''',用于给定时间段内泊松型事件的发生次数<br />
<br />
* [[Exponential distribution]], for the time before the next Poisson-type event occurs<br />
'''<font color="#ff8000">指数分布 Exponential Distribution</font>''',在下一次泊松型事件发生之前的时间<br />
<br />
* [[Gamma distribution]], for the time before the next k Poisson-type events occur<br />
'''<font color="#ff8000">伽马分布 Gamma Distribution</font>''',在接下来的k个泊松型事件发生之前的时间<br />
<br />
=== Absolute values of vectors with normally distributed components 具有正态分布分量的向量的绝对值===<br />
<br />
* [[Rayleigh distribution]], for the distribution of vector magnitudes with Gaussian distributed orthogonal components. Rayleigh distributions are found in RF signals with Gaussian real and imaginary components.<br />
'''<font color="#ff8000">瑞利分布 Rayleigh Distribution</font>''',用于具有高斯分布正交分量的矢量幅度分布。在具有高斯实部和虚部的RF信号中发现瑞利分布。<br />
<br />
* [[Rice distribution]], a generalization of the Rayleigh distributions for where there is a stationary background signal component. Found in [[Rician fading]] of radio signals due to multipath propagation and in MR images with noise corruption on non-zero NMR signals.<br />
'''<font color="#ff8000">莱斯分布 Rice Distribution</font>''',是在背景信号分量稳定的情况下瑞利分布的概括。由于多径传播而在无线电信号的Rician衰落中发现,并且在非零NMR信号中出现噪声破坏的MR图像中也发现了这种情况。<br />
<br />
=== Normally distributed quantities operated with sum of squares (for hypothesis testing) 以平方和运算的正态分布量(用于假设检验)===<br />
<br />
* [[Chi-squared distribution]], the distribution of a sum of squared [[standard normal]] variables; useful e.g. for inference regarding the [[sample variance]] of normally distributed samples (see [[chi-squared test]])<br />
'''<font color="#ff8000">卡方分布 Chi-squared Distribution</font>''',标准正态变量平方和的分布;有用的关于正态分布样本的样本方差的推论(请参见卡方检验)<br />
<br />
* [[Student's t distribution]], the distribution of the ratio of a [[standard normal]] variable and the square root of a scaled [[Chi squared distribution|chi squared]] variable; useful for inference regarding the [[mean]] of normally distributed samples with unknown variance (see [[Student's t-test]])<br />
'''<font color="#ff8000">学生t分布 Student‘s t Distribution</font>''',标准正态变量与缩放的卡方变量的平方根之比的分布;有助于推断方差未知的正态分布样本的平均值(请参阅学生的t检验)<br />
<br />
* [[F-distribution]], the distribution of the ratio of two scaled [[Chi squared distribution|chi squared]] variables; useful e.g. for inferences that involve comparing variances or involving [[R-squared]] (the squared [[Pearson product-moment correlation coefficient|correlation coefficient]])<br />
'''<font color="#ff8000">F-分布 F-Distribution</font>''',两个比例卡方变量的比例分布;有用的用于涉及比较方差或涉及R平方(相关系数平方)的推论<br />
<br />
=== As a conjugate prior distributions in Bayesian inference 作为贝叶斯推断中的共轭先验分布===<br />
{{Main|Conjugate prior}}<br />
<br />
* [[Beta distribution]], for a single probability (real number between 0 and 1); conjugate to the [[Bernoulli distribution]] and [[binomial distribution]]<br />
'''<font color="#ff8000">Beta分布 Beta Distribution</font>''',具有单个概率(0到1之间的实数);与伯努利分布和二项式分布共轭<br />
<br />
* [[Gamma distribution]], for a non-negative scaling parameter; conjugate to the rate parameter of a [[Poisson distribution]] or [[exponential distribution]], the [[Precision (statistics)|precision]] (inverse [[variance]]) of a [[normal distribution]], etc.<br />
伽玛分布,用于非负比例缩放参数;与泊松分布或指数分布的速率参数,正态分布的精度(逆方差)等共轭。<br />
<br />
* [[Dirichlet distribution]], for a vector of probabilities that must sum to 1; conjugate to the [[categorical distribution]] and [[multinomial distribution]]; generalization of the [[beta distribution]]<br />
'''<font color="#ff8000">Dirichlet分布 Dirichlet Distribution</font>''',对于必须为1的概率向量;与分类分布和多项式分布共轭; beta分布的一般化<br />
<br />
*[[Wishart distribution]], for a symmetric [[non-negative definite]] matrix; conjugate to the inverse of the [[covariance matrix]] of a [[multivariate normal distribution]]; generalization of the [[gamma distribution]]<ref>{{Cite book|title=Pattern recognition and machine learning|last=Bishop, Christopher M.|date=2006|publisher=Springer|isbn=0-387-31073-8|location=New York|oclc=71008143}}</ref><br />
'''<font color="#ff8000">Wishart分布 Wishart Distribution</font>''',用于对称非负定矩阵;与多元正态分布的协方差矩阵的逆共轭;伽玛分布的一般化<br />
<br />
=== Some specialized applications of probability distributions 概率分布的一些特殊应用===<br />
<br />
* The [[cache language model]]s and other [[Statistical Language Model|statistical language models]] used in [[natural language processing]] to assign probabilities to the occurrence of particular words and word sequences do so by means of probability distributions.<br />
在自然语言处理中使用的高速缓存语言模型和其他统计语言模型通过概率分布来为特定单词和单词序列的出现分配概率。<br />
<br />
* In quantum mechanics, the probability density of finding the particle at a given point is proportional to the square of the magnitude of the particle's [[wavefunction]] at that point (see [[Born rule]]). Therefore, the probability distribution function of the position of a particle is described by <math>P_{a\le x\le b} (t) = \int_a^b d x\,|\Psi(x,t)|^2 </math>, probability that the particle's position {{math|''x''}} will be in the interval {{math|''a'' ≤ ''x'' ≤ ''b''}} in dimension one, and a similar [[triple integral]] in dimension three. This is a key principle of quantum mechanics.<ref>{{Cite book|title=Physical chemistry for the chemical sciences|last=Chang, Raymond.|publisher=|others=Thoman, John W., Jr., 1960-|year=|isbn=978-1-68015-835-9|location=[Mill Valley, California]|pages=403–406|oclc=927509011}}</ref><br />
在量子力学中,在给定点处找到粒子的概率密度与该点处粒子波函数大小的平方成正比(请参阅博恩法则)。因此,粒子位置的概率分布函数描述为<math>P_{a\le x\le b} (t) = \int_a^b d x\,|\Psi(x,t)|^2 </math>,粒子位置的概率x在第一个维度中的间隔为a≤x≤b,在第三个维度中的间隔类似。这是量子力学的关键原理。<br />
<br />
* Probabilistic load flow in [[power-flow study]] explains the uncertainties of input variables as probability distribution and provide the power flow calculation also in term of probability distribution.<ref>{{Cite book|title=2008 Third International Conference on Electric Utility Deregulation and Restructuring and Power Technologies|last1=Chen|first1=P.|last2=Chen|first2=Z.|last3=Bak-Jensen|first3=B.|date=April 2008|isbn=978-7-900714-13-8|pages=1586–1591|chapter=Probabilistic load flow: A review|doi=10.1109/drpt.2008.4523658|s2cid=18669309}}</ref><br />
潮流研究中的概率潮流解释了作为概率分布的输入变量的不确定性,并以概率分布的形式提供了潮流计算。<br />
<br />
* Prediction of natural phenomena occurrences based on previous [[frequency distribution]]s such as [[tropical cyclone]]s, hail, time in between events, etc.<ref>{{Cite book|title=Statistical methods in hydrology and hydroclimatology|last=Maity, Rajib|isbn=978-981-10-8779-0|location=Singapore|oclc=1038418263|date = 2018-04-30}}</ref><br />
根据先前的频率分布(例如热带气旋,冰雹,事件之间的时间等)预测自然现象的发生。<br />
<br />
==See also 另请参见==<br />
{{Portal|Mathematics}}<br />
*[[Copula (statistics)]]<br />
Copula(统计数据)<br />
* [[Empirical probability]]<br />
经验概率<br />
* [[Histogram]]<br />
直方图<br />
* [[Likelihood function]]<br />
似然函数<br />
* [[Kirkwood approximation]]<br />
柯克伍德近似<br />
* [[Moment-generating function]]<br />
瞬时产生功能<br />
* [[Riemann–Stieltjes integral#Application to probability theory|Riemann–Stieltjes integral application to probability theory]]<br />
Riemann–Stieltjes积分#在概率论中的应用<br />
*[[Pairwise independence]]<br />
成对独立<br />
<br />
=== Lists 清单===<br />
<br />
* [[List of probability distributions]]<br />
概率分布的清单<br />
* [[List of statistical topics]]<br />
统计学话题的清淡<br />
=== Probability distributions 概率分布 ===<br />
<br />
* [[Conditional probability distribution]]<br />
条件概率分布<br />
* [[Joint probability distribution]]<br />
联合概率分布<br />
* [[Quasiprobability distribution]]<br />
拟概率分布<br />
<br />
== References ==<br />
=== Citations ===<br />
{{Reflist}}<br />
<br />
=== Sources ===<br />
{{refbegin|}}<br />
* {{cite journal|doi=10.1016/j.ejmp.2014.05.002|pmid=25059432|title=Data distributions in magnetic resonance images: A review|url=|journal=[[Physica Medica]]|volume=30|issue=7|pages=725–741|year=2014|last1=den Dekker|first1=A. J.|last2=Sijbers|first2=J.}}<br />
* {{cite book|last=Vapnik|first=Vladimir Naumovich|year=1998|title=Statistical Learning Theory|publisher=John Wiley and Sons}}<br />
{{refend}}<br />
<br />
==External links==<br />
{{commons|Probability distribution|Probability distribution}}<br />
*{{springer|title=Probability distribution|id=p/p074900}}<br />
*[http://threeplusone.com/FieldGuide.pdf Field Guide to Continuous Probability Distributions], Gavin E. Crooks.</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19348
用户:Thingamabob
2020-11-29T03:14:14Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
<br />
用户名:Thingamabob <br />
<br />
微信:Thingamabob_ <br />
<br />
院校:清华大学 <br />
<br />
专业:生物医学工程 <br />
<br />
兴趣:脑机接口 <br />
<br />
其他: <br />
<br />
1. 大二,偶尔透露出小学生气质<br />
<br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
<br />
3. 在学了在学了 <br />
<br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”<br />
<br />
5. 在做自己喜欢并热爱并愿为其消耗一生的事<br />
<br />
最后分享下最近的日常<br />
<br />
[[文件:Thingamabob.png]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19347
用户:Thingamabob
2020-11-29T03:14:03Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
<br />
用户名:Thingamabob <br />
<br />
微信:Thingamabob_ <br />
<br />
院校:清华大学 <br />
<br />
专业:生物医学工程 <br />
<br />
兴趣:脑机接口 <br />
<br />
其他: <br />
<br />
1. 大二,偶尔透露出小学生气质<br />
<br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
<br />
3. 在学了在学了 <br />
<br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”<br />
<br />
5. 在做自己喜欢并热爱并愿为其消耗一生的事<br />
<br />
最后分享下最近的日常<br />
<br />
[[文件:Thingamabob.png|缩略图]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Thingamabob.png&diff=19346
文件:Thingamabob.png
2020-11-29T03:13:53Z
<p>Thingamabob:</p>
<hr />
<div>-</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19345
用户:Thingamabob
2020-11-29T03:07:45Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
<br />
用户名:Thingamabob <br />
<br />
微信:Thingamabob_ <br />
<br />
院校:清华大学 <br />
<br />
专业:生物医学工程 <br />
<br />
兴趣:脑机接口 <br />
<br />
其他: <br />
<br />
1. 大二<br />
<br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
<br />
3. 在学了在学了 <br />
<br />
4. 在做自己喜欢并热爱并愿为其消耗一生的事<br />
<br />
5. 最近最大的焦虑是“吾生也有涯而知也无涯”</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19344
用户:Thingamabob
2020-11-29T03:07:37Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
<br />
用户名:Thingamabob <br />
<br />
微信:Thingamabob_ <br />
<br />
院校:清华大学 <br />
<br />
专业:生物医学工程 <br />
<br />
兴趣:脑机接口 <br />
<br />
其他: <br />
<br />
1. 大二<br />
<br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
<br />
3. 在学了在学了 <br />
<br />
4. 在做自己喜欢并热爱并愿为其消耗一生的事<br />
<br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19343
用户:Thingamabob
2020-11-29T03:06:44Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
<br />
用户名:Thingamabob <br />
<br />
微信:Thingamabob_ <br />
<br />
院校:清华大学 <br />
<br />
专业:生物医学工程 <br />
<br />
兴趣:脑机接口 <br />
<br />
其他: <br />
<br />
1. 大二 <br />
<br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
<br />
3. 在学了在学了 <br />
<br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19342
用户:Thingamabob
2020-11-29T03:06:15Z
<p>Thingamabob:</p>
<hr />
<div>姓名:杨煜行 <br />
用户名:Thingamabob <br />
微信:Thingamabob_ <br />
院校:清华大学 <br />
专业:生物医学工程 <br />
兴趣:脑机接口 <br />
其他: <br />
1. 大二 <br />
2. 神经工程是方向,脑机接口是梦想是信仰 <br />
3. 在学了在学了 <br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E7%94%A8%E6%88%B7:Thingamabob&diff=19341
用户:Thingamabob
2020-11-29T03:05:58Z
<p>Thingamabob:建立内容为“姓名:杨煜行 用户名:Thingamabob 微信:Thingamabob_ 院校:清华大学 专业:生物医学工程 兴趣:脑机接口 其他: 1. 大二 2.…”的新页面</p>
<hr />
<div>姓名:杨煜行<br />
用户名:Thingamabob <br />
微信:Thingamabob_<br />
院校:清华大学<br />
专业:生物医学工程<br />
兴趣:脑机接口<br />
其他:<br />
1. 大二<br />
2. 神经工程是方向,脑机接口是梦想是信仰<br />
3. 在学了在学了<br />
4. 最近最大的焦虑是“吾生也有涯而知也无涯”</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Shape2.png&diff=18148
文件:Shape2.png
2020-11-12T03:25:48Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Simulationmatchingmodelscalinglaws.png&diff=18147
文件:Simulationmatchingmodelscalinglaws.png
2020-11-12T03:23:25Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Shape1.png&diff=18146
文件:Shape1.png
2020-11-12T03:21:12Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Multistagespatialnetwork.png&diff=18145
文件:Multistagespatialnetwork.png
2020-11-12T03:17:40Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Matchingprocess.png&diff=18144
文件:Matchingprocess.png
2020-11-12T03:16:25Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Matchinggrowthspatialattractionmodelnodes.png&diff=18143
文件:Matchinggrowthspatialattractionmodelnodes.png
2020-11-12T03:15:30Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Matchinggrowthspatialattractionmodellondongbeijing.png&diff=18142
文件:Matchinggrowthspatialattractionmodellondongbeijing.png
2020-11-12T03:14:35Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Matchinggrowthheterogenousmodeldegreedistribution.png&diff=18141
文件:Matchinggrowthheterogenousmodeldegreedistribution.png
2020-11-12T03:13:40Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%96%87%E4%BB%B6:Ddimension.png&diff=18140
文件:Ddimension.png
2020-11-12T03:13:09Z
<p>Thingamabob:</p>
<hr />
<div></div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%81%8F%E5%B7%AE%E6%96%B9%E5%B7%AE%E6%9D%83%E8%A1%A1&diff=15299
偏差方差权衡
2020-10-15T12:35:43Z
<p>Thingamabob:创建页面,内容为“在[https://en.wikipedia.org/wiki/Statistics 统计学]与[https://en.wikipedia.org/wiki/Machine_learning 机器学习]中,偏差方差分析是一组预测性模…”</p>
<hr />
<div>在[https://en.wikipedia.org/wiki/Statistics 统计学]与[https://en.wikipedia.org/wiki/Machine_learning 机器学习]中,偏差方差分析是一组预测性模型的特性,意味着参数估计[https://en.wikipedia.org/wiki/Bias_(statistics) 偏差]较小的模型在样本间的参数估计有较高的方差,反之亦然。偏差方差困境是不能同时最小化这两个误差来源的冲突问题,这两个误差来源让有监督学习算法不能在训练集上很好地进行泛化。<br />
<br />
*[https://en.wikipedia.org/wiki/Bias_of_an_estimator 偏差(bias)]来自于学习算法中错误假设造成的误差。高偏差会导致算法不能将特征与目标输出很好地关联起来。(欠拟合)<br />
<br />
*[https://en.wikipedia.org/wiki/Variance 方差(variance)]来自于算法对训练集中小波动敏感性造成的误差。高方差会导致算法对训练集中的随机噪声进行建模而不是目标输出。([https://en.wikipedia.org/wiki/Overfitting 过拟合])<br />
<br />
这种权衡适用于所有的[https://en.wikipedia.org/wiki/Supervised_learning 有监督学习]模型:分类,回归(函数拟合),<ref name="geman">{{cite journal |last1=Geman |first1=Stuart |authorlink1=Stuart Geman |author2=E. Bienenstock |author3=R. Doursat |year=1992 |title=Neural networks and the bias/variance dilemma |journal=Neural Computation |volume=4 |pages=1–58 |doi=10.1162/neco.1992.4.1.1 |url=http://web.mit.edu/6.435/www/Geman92.pdf}}</ref><ref>Bias–variance decomposition, In Encyclopedia of Machine Learning. Eds. Claude Sammut, Geoffrey I. Webb. Springer 2011. pp. 100-101</ref>结构化输出学习。它也被用来解释启发式学习在人类学习中的有效性。<ref name="ReferenceA">{{Cite journal | last1 = Gigerenzer | first1 = Gerd| last2 = Brighton | first2 = Henry| doi = 10.1111/j.1756-8765.2008.01006.x | title = Homo Heuristicus: Why Biased Minds Make Better Inferences | journal = Topics in Cognitive Science | volume = 1 | pages = 107–143| year = 2009 | pmid = 25164802| pmc = }}</ref><br />
<br />
偏差方差困境是在特定问题下,分析学习算法泛化预期误差的一种方式,[https://en.wikipedia.org/wiki/Generalization_error 泛化误差]来自于三个部分:偏差,方差,以及一个称之为“不可避免误差”的量,这个误差一般是问题本身的噪音产生的。<br />
<br />
<br />
==动机==<br />
<br />
方差偏差分析是有监督学习的一个核心问题。理想情况下,人们希望选择一种模型,这种模型既能准确捕获训练数据规律性,又能很好的概括未知数据。不幸的是,通常是不可能同时做到这两点的。高方差的学习方法可能能够很好的表达它的数据集但,但是可能过度拟合噪声或不具备代表性的训练数据。相比之下,低方差的算法通常会生成一个更简单的模型,这种模型不会过拟合,但是会导致在训练数据上欠拟合,无法捕捉到重要的规律。<br />
低偏差的模型通常比较复杂(如高阶回归多项式),这使得它们能够更准确的表达训练集。然而,在这个过程中,它们也可能表示了训练集中的一个巨大的噪声的一部分,尽管复杂性增加了,也使得它们的预测变得不是那么的准确。相比之下,具有较高偏差的模型往往相对较简单(低阶甚至是线性的回归多项式),但是在训练集之外应用时可能会产生较低方差的预测。<br />
<br />
==偏差与方差的平方分解==<br />
<br />
假设我们有一个训练集包含一个点集 <math>x_1, \cdots , x_n</math> 以及与<math>x_i</math>相关的实值<math>y_i</math>。我们假定一个有噪声的函数<math>y=f(x)+\varepsilon</math>,其中<math>\varepsilon</math>是有着0均值和<math>\sigma^2</math>方差的噪声。<br />
<br />
我们想要通过学习算法找到一个函数<math>\hat{f}(x)</math>使其尽量拟合真实的函数<math>f(x)</math>。我们所谓的“尽可能”是使用<math>\hat{f}(x)</math>与<math>y</math>之间的均方误差来表达的,即我们想要<math>(y - \hat{f}(x))^2</math>对于<math>x_1, \cdots , x_n</math>和样本外的点都最小。当然,我们不可能完美做到这一点,因为<math>y_i</math>必定会包含噪声<math>\varepsilon</math>,这意味对于我们得到的所有函数,我们都要接受其中存在这不可避免的误差。<br />
任意一个有监督机器学习算法,都可以使得<math>\hat{f}(x)</math>对训练集之外的点进行泛化。结果就是,无论我们选择了哪个<math>\hat{f}(x)</math>函数,我们可以使用一个样本外的任意<math>x</math>分解期望误差:<br />
<br />
:<math>\mathrm { E } \left[ ( y - \hat { f } ( x ) ) ^ { 2 } \right] = ( \operatorname { Bias } [ \hat { f } ( x ) ] ) ^ { 2 } + \mathrm { Var } [ \hat { f } ( x ) ] + \sigma ^ { 2 }</math><br />
<br />
其中:<br />
<br />
<br />
:<math>\text { Bias } [ \hat { f } ( x ) ] = \mathrm { E } [ \hat { f } ( x ) - f ( x ) ]</math>以及:<br />
:<math>\begin{align}\operatorname{Var}\big[\hat{f}(x)\big] = \operatorname{E}[\hat{f}(x)^2] - \Big(\operatorname{E}[{\hat{f}}(x)]\Big)^2\end{align}</math><br />
<br />
期望包括了不同训练集的选择,这些样本都来自于同样的联合分布P(x,y),这三个项分别表示:<br />
<br />
*学习方法偏差的平方可以视作因为简化假设导致的误差。比如,当我们想要拟合一个非线性的函数<math>f(x)</math>却使用了一个线性的模型,于是估计<math>\hat{f}(x)</math>就会存在存在误差。<br />
<br />
*学习方法的方差或者直观地来说就是学习方法<math>\hat{f}(x)</math>多大程度上偏离了其均值。<br />
<br />
*不可约误差<math>\sigma^2</math>。因为这三项都是非负的,这三项组成了训练集外样本的期望误差的下界。<br />
<br />
<math>\hat{f}(x)</math>的模型越复杂,那么它就可以拟合越多的数据点,偏差也就会越低。然而,复杂度会使得模型更加“偏向于”拟合数据点,因此方差就会变大。<br />
<br />
=== 推导 ===<br />
<br />
偏差方差平方分解的推导过程如下。<ref>{{cite web |first1=Sethu |last1=Vijayakumar |title=The Bias–Variance Tradeoff |publisher=University Edinburgh |year=2007 |accessdate=19 August 2014 |url=http://www.inf.ed.ac.uk/teaching/courses/mlsc/Notes/Lecture4/BiasVariance.pdf}}</ref><ref>{{cite web |title=Notes on derivation of bias-variance decomposition in linear regression |first=Greg|last=Shakhnarovich |year=2011 |accessdate=20 August 2014 |url=http://ttic.uchicago.edu/~gregory/courses/wis-ml2012/lectures/biasVarDecom.pdf|archiveurl=https://web.archive.org/web/20140821063842/http://ttic.uchicago.edu/~gregory/courses/wis-ml2012/lectures/biasVarDecom.pdf|archivedate=21 August 2014}}</ref>为了记号上的方便,引入两个缩写<math>f = f(x)</math> 以及 <math>\hat{f} = \hat{f}(x)</math>。首先,回忆一下,通过定义对于任意的随机变量<math>X</math>,我们有:<br />
:<math>\begin{align}\operatorname{Var}[X] = \operatorname{E}[X^2] - \Big(\operatorname{E}[X]\Big)^2\end{align}</math><br />
整理得到:<br />
:<math>\begin{align}\operatorname{E}[X^2] = \operatorname{Var}[X] + \Big(\operatorname{E}[X]\Big)^2\end{align}</math><br />
因为 <math>f</math> 是[https://en.wikipedia.org/wiki/Deterministic_algorithm 确定的]<br />
:<math>\begin{align}\operatorname{E}[f] = f\end{align}</math>.<br />
这里, 给定 <math>y = f + \epsilon</math> and <math>\operatorname{E}[\epsilon] = 0</math>, 令 <math>\operatorname{E}[y] = \operatorname{E}[f + \epsilon] = \operatorname{E}[f] = f</math>.<br />
同理因为 <math>\operatorname{Var}[\varepsilon] = \sigma^2,</math><br />
于是, 因为 <math>\epsilon</math> 和 <math>\hat{f}</math> 是独立的,我们可以写成:<br />
:<math>\begin{align}\operatorname{E}\big[(y - \hat{f})^2\big] & = \operatorname{E}[y^2 + \hat{f}^2 - 2 y\hat{f}] \\ & = \operatorname{E}[y^2] + \operatorname{E}[\hat{f}^2] - \operatorname{E}[2y\hat{f}] \\ & = \operatorname{Var}[y] + \operatorname{E}[y]^2 + \operatorname{Var}[\hat{f}] + \Big(\operatorname{E}[\hat{f}]\Big)^2 - 2f\operatorname{E}[\hat{f}] \\ & = \operatorname{Var}[y] + \operatorname{Var}[\hat{f}] + \Big(f^2 - 2f\operatorname{E}[\hat{f}] + (\operatorname{E}[\hat{f}])^2\Big) \\ & = \operatorname{Var}[y] + \operatorname{Var}[\hat{f}] + (f - \operatorname{E}[\hat{f}])^2 \\ & = \sigma^2 + \operatorname{Var}[\hat{f}] + \operatorname{Bias}[\hat{f}]^2\end{align}</math><br />
<br />
=== 回归应用 ===<br />
<br />
偏差方差分解回归[https://en.wikipedia.org/wiki/Regularization_(mathematics) 正则化]方法的基础,比如 [https://en.wikipedia.org/wiki/Lasso_(statistics) Lasso] 与 [https://en.wikipedia.org/wiki/Ridge_regression ridge] 回归。正则化方法将偏置项引入了回归的解,这样可以大大减少相对与[https://en.wikipedia.org/wiki/Ordinary_least_squares 一般的最小平方(OLS)]的解法的方差。虽然OLS的解法提供了非偏置回顾估计,但正则化技术产生的较低的方差提供了优越的MSE的性能。<br />
<br />
=== 分类应用 ===<br />
偏差方差分解最初是为最小二乘法回归提出的。对于在[https://en.wikipedia.org/wiki/0-1_loss 0-1损失](错误分类率)下的分类,可能会发现类似的分解。<ref>{{cite conference |last=Domingos |first=Pedro |title=A unified bias-variance decomposition |conference=ICML |year=2000 |url=http://homes.cs.washington.edu/~pedrod/bvd.pdf}}</ref><ref>{{cite journal |first1=Giorgio |last1=Valentini |first2=Thomas G. |last2=Dietterich |title=Bias–variance analysis of support vector machines for the development of SVM-based ensemble methods |journal=[[Journal of Machine Learning Research|JMLR]] |volume=5 |year=2004 |pages=725–775}}</ref> 或者,如果分类问题可以被称为概率分类,那么对于真实概率的预期平方误差可以像之前一样地分解。<ref>{{cite book |first1=Christopher D. |last1=Manning |first2=Prabhakar |last2=Raghavan |first3=Hinrich |last3=Schütze |title=Introduction to Information Retrieval |publisher=Cambridge University Press |year=2008 |url=http://nlp.stanford.edu/IR-book/ |pages=308–314}}</ref><br />
<br />
== 方法 ==<br />
<br />
<br />
[https://en.wikipedia.org/wiki/Dimensionality_reduction 降维]和[https://en.wikipedia.org/wiki/Feature_selection 特征选择]可以通过简化模型来减少方差。同样,一个更大的训练集也会减少方差。<ref>{{cite book | last = Belsley | first = David | title = Conditioning diagnostics : collinearity and weak data in regression | publisher = Wiley | location = New York | year = 1991 | isbn = 978-0471528890 }}</ref>增加特征(预测器)倾向于减少偏差,而不是引入额外的方差。学习算法通常有一些控制偏差和方差的可调整参数。列如:<br />
<br />
<br />
* ([https://en.wikipedia.org/wiki/Generalized_linear_model 广义的])线性模型可以被正则化来减小方差但是代价是增大偏差。<br />
<br />
* 在[https://en.wikipedia.org/wiki/Artificial_neural_network 人工神经网络]中,随着隐层数量的增加,方差增大但是偏差减小。像GLMs,通常会使用正则化方法。<br />
<br />
* 在[https://en.wikipedia.org/wiki/K-nearest_neighbor k邻近]模型中,一个很大的k值会导致很大的偏差和很低的偏差(如下)。<br />
<br />
* 在[https://en.wikipedia.org/wiki/Instance-based_learning 实例学习]中,正则化可以通过改变不同的原型和范例的组合来实现。<ref>{{cite journal | last1 = Gagliardi | first1 = F | year = 2011 | title = Instance-based classifiers applied to medical databases: diagnosis and knowledge extraction | url = | journal = Artificial Intelligence in Medicine | volume = 52 | issue = 3| pages = 123–139 | doi = 10.1016/j.artmed.2011.04.002 }}</ref><br />
<br />
* 在[decision trees 决策树]中,树的深度决定了方差。决策树通常会剪枝来控制方差。一种解决这种权衡的方法是使用混合模型和[https://en.wikipedia.org/wiki/Ensemble_learning 集成学习]。.<ref>Jo-Anne Ting, Sethu Vijaykumar, Stefan Schaal, Locally Weighted Regression for Control. In Encyclopedia of Machine Learning. Eds. Claude Sammut, Geoffrey I. Webb. Springer 2011. p. 615</ref><ref>Scott Fortmann-Roe. Understanding the Bias–Variance Tradeoff. 2012. http://scott.fortmann-roe.com/docs/BiasVariance.html</ref>比如,[https://en.wikipedia.org/wiki/Boosting_(machine_learning) boosting]算法组合很多“弱”(高偏差)模型来集成出一个低方差且独立的模型,而[https://en.wikipedia.org/wiki/Bootstrap_aggregating bagging]算法用一种方式组合了“强”学习器来减小他们的方差。<br />
<br />
=== k邻近 ===<br />
<br />
k邻近回归的情况下,参数k的偏差方差分解的[https://en.wikipedia.org/wiki/Closed-form_expression 闭式表达]是存在的::<math>\operatorname{E}[(y - \hat{f}(x))^2\mid X=x] = \left( f(x) - \frac{1}{k}\sum_{i=1}^k f(N_i(x)) \right)^2 + \frac{\sigma^2}{k} + \sigma^2</math>其中<math>N_1(x), \dots, N_k(x)</math>是x的k个训练集中的邻近。偏差(第一项)是k的单调递增函数,然而偏差(第二项)是k的递减函数。实际上,在可行的假设下,最邻近估计器的偏差会完全消失当训练集趋向于无穷大的时候。<br />
<br />
<br />
=== 人类学习中的应用 ===<br />
<br />
虽然我们在机器学习的背景下广泛讨论了这个问题,但在人类认知方面,尤其是 [https://en.wikipedia.org/wiki/Gerd_Gigerenzer Gerd Gigerenzer] 和他同事在启发式学习背景下,对偏差方差困境进行了研究。他们认为(见参考),人类大脑通过采用高偏差/低方差的启发式学习方法,在典型的稀疏、缺乏特点的训练集中,人类大脑解决了这种困境。这反映了这样一个事实,零偏差方法对新情况的泛化性较差,而且不合理的假定准确推测了世界的真实状况。由此尝试的启发式学习方法相对简单,但是在更广泛的情况下会有更好的推论。[ https://en.wikipedia.org/wiki/Stuart_Geman Geman]等人认为,偏差方差困境意味着一般性的物体识别这样的能力是无法从零开始学习的,而是需要一定的“硬编码”,再根据经验来调整。这是因为无模型的推理方法需要不切实际的大型训练集,才能避免高方差。<br />
<br />
==参考==<br />
<br />
* [[Accuracy and precision]]<br />
* [[Bias of an estimator]]<br />
* [[Gauss–Markov theorem]]<br />
* [[Hyperparameter optimization]]<br />
* [[Minimum-variance unbiased estimator]]<br />
* [[Model selection]]<br />
* [[Regression model validation]]<br />
* [[Supervised learning]]{{Div col end}}<br />
<br />
==引用==<br />
<br />
<references/><br />
<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%8A%95%E5%85%A5%E4%BA%A7%E5%87%BA%E8%A1%A8&diff=15192
投入产出表
2020-10-14T14:23:36Z
<p>Thingamabob:创建页面,内容为“投入产出表是投入产出分析(Input-output analysis)<ref>{{cite book|last=Leontief|first=Wassily| title=Input-output Economics|time=1966|publisher=Oxford…”</p>
<hr />
<div>投入产出表是[[投入产出分析]](Input-output analysis)<ref>{{cite book|last=Leontief|first=Wassily| title=Input-output Economics|time=1966|publisher=Oxford University Press}}</ref><ref>{{cite book|last=Miller|first=Ronald E. | title=Input–Output Analysis|time=2009|publisher=Cambridge University Press}}</ref>的一种基本度量,所谓的投入产出表就是类似下面的表格:<br />
{| class="wikitable"<br />
|-<br />
! 部门!! 1!! ...!! j!! ... !! N !! 最终需求 !! 总产出<br />
|-<br />
| 1|| z<sub>11</sub>|| ...|| z<sub>1j</sub>|| ... || z<sub>1N</sub>|| f<sub>1</sub>|| x<sub>1</sub><br />
|-<br />
| 2|| z<sub>21</sub>|| ...|| z<sub>2j</sub>|| ... || z<sub>2N</sub>|| f<sub>2</sub>|| x<sub>2</sub><br />
|-<br />
| ...|| ...|| ...|| ...|| ...|| ... || ...|| ...<br />
|-<br />
| N || z<sub>N1</sub>|| ... || z<sub>Nj</sub> || ...|| z<sub>NN</sub>|| f<sub>N</sub>|| x<sub>N</sub><br />
|}<br />
<br />
其中,1,2,3,...,N表示工业系统中的N个部门(Sector),例如农业、林业、造纸业等等。z<sub>ij</sub>表示从i部门对j部门的投入量(一般以货币来衡量)。例如,如果i表示林业,j表示造纸业,z<sub>ij</sub>=350000,则表示造纸业从林业部门购买了350000人民币的原始木材。倒数第二列f<sub>i</sub>则表示第i部门到最终需求(即消费者的最终消费)的直接流量(以货币衡量)。例如,如果f<sub>j</sub>=500000,就表示人们对纸张的最终需求有500000元。最后一列x<sub>i</sub>表示行业i的总产出。投入产出表要求:<br />
<br />
<math><br />
x_i=\sum_{k=1}^{N}z_{ik}+f_{i}<br />
</math><br />
<br />
它表示第i部门的总产出应该等于其它所有工业部门对i部门的需求再加上最终消费者对i的直接需求。我们可以将投入产出表转变成一张网络,这个网络就是[[投入产出网]]<br />
<br />
下图展示的一张实际的投入产出表,其来源为:OECD STAN input-output table (http://www.oecd.org/trade/input-outputtables.htm)<ref name="iotableexample">{{cite journal|last=Yamano|first=Norihiko|last2=Ahmad|first2=Nadim|title=THE OECD INPUT-OUTPUT DATABASE: 2006 EDITION|journal=STI Working Paper|time=2006|url=http://www.oecd.org/sti/37585924.pdf}}</ref><br />
<br />
[[File:iotable-australia.png|400px|缩略图|Australia Input-Output Table]]<br />
<br />
其中行表示投入,列表示产出。其中编号的1~12为为工业部门,其它各项均为附加值或最终需求。<br />
<br />
==投入产出表数据来源==<br />
<br />
===OECD STAN input-output Data===<br />
<br />
这个数据库是OECD组织各国编写的(网站:[http://www.oecd.org/trade/input-outputtables.htm]),包含了近40个国家,30多个工业部门,3个不同时期的投入产出表。该数据库的数据来源均是相应国家的统计数据,按照OECD的要求统一编写形成的投入产出表。<br />
<br />
====原始数据格式====<br />
<br />
网站提供了两种查看数据的模式:1、直接在Web页面上进行交互式操作;2、下载到本地。下载到本地的数据表如下图所示:<br />
<br />
[[File:slice.png|700px]]<br />
<br />
Country表示国家,Period表示时期,其中Currency表示计量单位(分为本国货币和美元两种)、Row Sector,Col Sector分别是投入部门和产出部门,Value表示数值。<br />
<br />
====关于附加值====<br />
<br />
在这个数据集中,附加值被分解为多个项,但是这些项目之间并非彼此独立,而是包括了重复的部分。具体来说,请见下表:<br />
<br />
[[File:valueaddedill.png|600px]]<br />
<br />
在这个表中,a+b+c+d+e+l是总和的附加值,而如果考虑f,g,h,i,j,k等项则包括了重复值。<br />
<br />
==参考文献==<br />
<br />
<references/><br />
<br />
[[category:流网络]]<br />
[[category:经济学]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%BD%BC%E5%BE%97%C2%B7%E6%96%AF%E5%A1%94%E5%BE%B7%E5%8B%92_Peter_F_Stadler&diff=15191
彼得·斯塔德勒 Peter F Stadler
2020-10-14T14:22:27Z
<p>Thingamabob:创建页面,内容为“== 基本信息 == 右 === 姓名 === Peter F Stadler(彼得·斯塔德勒) === 出生日期 === 1965年12月24日 ===…”</p>
<hr />
<div>== 基本信息 ==<br />
[[File:Peter F Stadler.jpeg|缩略图|右]]<br />
=== 姓名 ===<br />
Peter F Stadler(彼得·斯塔德勒)<br />
=== 出生日期 ===<br />
1965年12月24日<br />
=== 学习经历 ===<br />
* 曾就读于 Mathematik大学进修化学、物理和天文学。<br />
* 1990年,他在切米的彼得 · 舒斯特尔工作。 <br />
* 1990年至1991年,他在马克斯 · 普朗克生理化学研究所担任曼弗雷德 · 埃根的博士后。 <br />
* 于1994年在维也纳大学的理论化学系学习,直到2002年成为大学教授。 <br />
* 从2002年9月开始,斯塔德勒就是莱比锡大学的生物信息学教授,自1994年以来,他一直在圣菲研究所从事相关研究,并于2010年开始致力于数学科学的研究。<br />
=== 研究领域 ===<br />
生物信息学,化学<br />
=== 主要职位及荣誉 ===<br />
* 斯塔德尔用生物信息学和基因组 RNA 生物信息学研究进化。 他在基因调控过程中参与了核糖核酸的转录;<br />
* 是德国学术界最重要的结构与进化生物学家之一。<br />
== 发表著作 ==<br />
* [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2212820/?rendertype=abstract 《Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project》]Nature,Pages:799(2007/6,引用次数:4932)<br />
* [https://www.researchgate.net/publication/226552635_Fast_Folding_and_Comparison_of_RNA_Secondary_Structures 《Fast folding and comparison of RNA secondary structures》]Nature,Pages:487(2000/9,引用次数:2512)<br />
* [https://www.docin.com/p-854245433.html 《RNA maps reveal new RNA classes and a possible function for pervasive transcription》]Science,Pages:1067(2007,引用次数:2085)<br />
* [https://www.docin.com/p-1744466159.html 《ViennaRNA Package 2.0》]Physical review E,Pages:1805(2011,引用次数:2036)<br />
== 联系方式 ==<br />
* 工作地邮箱: studienbuero@mathematik.uni-leipzig.de<br />
<br />
== 相关链接 ==<br />
<br />
1、[http://www.bioinf.uni-leipzig.de/~studla/ 个人主页]<br />
<br />
2、[https://de.wikipedia.org/wiki/Peter_F._Stadler 维基词条]<br />
<br />
3、[https://scholar.google.com/citations?hl=zh-CN&user=pVnGRlkAAAAJ 谷歌学术主页]<br />
<br />
[[Category:复杂系统]] <br />
<br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%BC%A0%E6%BD%98_Pan_Zhang&diff=15190
张潘 Pan Zhang
2020-10-14T14:22:01Z
<p>Thingamabob:创建页面,内容为“{{#seo: * |keywords=张潘,Pan Zhang,复杂系统,统计物理 * |description=名字,研究领域 * }} == 基本信息 == 右 ===…”</p>
<hr />
<div>{{#seo:<br />
* |keywords=张潘,Pan Zhang,复杂系统,统计物理<br />
* |description=名字,研究领域<br />
* }}<br />
<br />
== 基本信息 ==<br />
[[File:Pan Zhang.jpg|缩略图|右]]<br />
=== 姓名 ===<br />
张潘(Pan Zhang)<br />
=== 出生地及日期 ===<br />
1983年11月生于安徽<br />
=== 研究领域 ===<br />
研究方向为统计物理与复杂系统,主要内容如下:<br />
自旋玻璃理论,消息传递算法<br />
组合优化问题<br />
统计物理中的反问题,统计推断问题<br />
随机矩阵,谱算法,谱图理论<br />
== 主要履历 ==<br />
2000-2004 兰州大学本科<br /><br />
2004-2009 兰州大学硕博, 导师陈勇<br /><br />
2007-2009 中科院理论物理研究所博士联合培养, 导师周海军<br /><br /><br />
2010-2012 意大利都灵理工博后,Riccardo Zecchina组<br /><br />
2012-2013 巴黎E.S.P.C.I.博后,Florent Krzakala组<br /><br />
2013-2015 美国Santa Fe Institute博后,Cris Moore组<br /><br /><br />
2015-至今 中国科学院理论物理研究所副研究员<br /><br />
2016.3 日本京都大学Yukawa Institute for Theoretical Physics 访问副教授<br /><br />
现任中国科学院理论物理研究所教授<br />
<br />
== 发表文章 ==<br />
* [https://www.pnas.org/content/pnas/110/52/20935.full.pdf Spectral redemption in clustering sparse networks]Proceedings of the National Academy of Sciences 110 (52), 20935-20940(2013/12/24,引用次数:398)<br />
<br />
* [https://www.pnas.org/content/pnas/111/51/18144.full.pdf Scalable detection of statistically significant communities and hierarchies, using message passing for modularity] Proceedings of the National Academy of Sciences 111 (51), 18144-18149(2014/12/23,引用次数:89)<br />
<br />
* [https://arxiv.org/pdf/1207.3994.pdf Model selection for degree-corrected block models] Journal of Statistical Mechanics: Theory and Experiment 2014 (5), P05007(2014/5/16,引用次数:70)<br />
<br />
* [https://journals.aps.org/prx/pdf/10.1103/PhysRevX.6.031005 Detectability Thresholds and Optimal Algorithms for Community Structure in Dynamic Networks] Physical Review X 6 (3), 031005(2016/7/13,引用次数:56)<br />
<br />
* [https://arxiv.org/pdf/cond-mat/0603237.pdf Optimized annealing of traveling salesman problem from the nth-nearest-neighbor distribution] Physica A: Statistical Mechanics and its Applications 371 (2), 627-632(2006/11/15,引用次数:39)<br />
<br />
== 科研项目及成果 ==<br />
<br />
===[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.080602 利用变分自回归网络求解统计力学]===<br />
<br />
计算自由能,估计物理量,生成不相关的样本是统计力学的基本问题。 该项目提出了一个新的框架来解决有限大小系统的统计力学问题, 该方法扩展了已有的基于自回归神经网络的变分平均场方法,该神经网络模型支持配置的归一化概率的直接抽样和精确计算。<br />
<br />
网络的训练采用强化学习的策略梯度方法,无偏估计变分参数的梯度。 我们已经成功地将我们的方法应用于几个经典系统,共包括2d Ising 模型、 Hopfield 模型、 sherlington-Kirkpatrick 自旋玻璃模型和逆 Ising 模型。<br />
<br />
该论文现已发表在《 Physical Review Letter》上,并作为编辑推荐进行刊登。<br />
<br />
=== [https://journals.aps.org/prx/abstract/10.1103/PhysRevX.8.031012 基于矩阵乘积状态的无监督生成建模] ===<br />
<br />
也许很多读者都熟悉Boltzmann机器,该机器使用Boltzmann分布对数据的联合概率分布进行建模。 玻尔兹曼机是统计学物理对机器学习的重要贡献。 在《 Physical Review X》的这篇论文中,我们提出了一个从量子物理学那里借来的新的无监督机器学习模型,该模型使用博恩法则对数据的联合分布进行建模。 因此,我们称其为“生机”。 该模型将张量网络和生成模型连接起来。 <br />
<br />
您可以找到有关张量网络,矩阵乘积状态和生成学习的主题的[http://lib.itp.ac.cn/html/panzhang/mps/tutorial/ 教程]和[http://lib.itp.ac.cn/html/panzhang/mps/tutorial/mps_tutorial.zip Jupyter文件代码]。<br />
<br />
=== [https://arxiv.org/pdf/1609.02906.pdf 基于正则化学习的全局结构稳健谱检测] ===<br />
<br />
光谱方法在检测可以表示为矩阵的给定数据中的全局结构时很流行。 但是,当数据矩阵稀疏或嘈杂时,由于稀疏性或噪声引起的特征向量(或奇异向量)的局部化,经典的频谱方法通常无法工作。 在本文(NIPS 2016)中,我们提出了一种通过从局部特征向量学习正则化矩阵来解决局部化问题的通用方法。 这是算法“ X-Laplacian”的演示。<br />
<br />
代码戳[http://lib.itp.ac.cn/html/panzhang/xlap/xlap_demo.zip 这里]<br />
<br />
=== [https://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.031005 动态网络中社区结构的可检测性阈值及优化算法] ===<br />
<br />
许多现实世界的网络都是动态的,节点会随着时间以复杂的方式更改其连接和从属关系。 这种情况使社区检测更具挑战性,但是跨时间的相关性提供了规避此问题的方法。 在这篇《 Physical Review X》的论文中,我们对恢复动态网络中底层社区结构的能力得出了精确的数学限制,这仅取决于隐藏社区的强度以及节点更改其社区成员的速度。<br />
<br />
=== [https://www.pnas.org/content/early/2014/12/04/1409770111.abstract 使用消息传递实现模块化,对具有统计意义的社区和层次结构进行可伸缩性检测] ===<br />
<br />
最大化模块化是检测网络社区的最流行方法。 但是,它容易过拟合。<br />
<br />
在这篇PNAS论文中,我们与克里斯·摩尔(Cris Moore)一起提出了利用统计物理学的思想来解决这一过拟合问题的方法,并提出了一种用于检测大型网络中社区和阶层的有效算法。<br />
<br />
=== [https://www.pnas.org/content/110/52/20935.abstract 聚类稀疏网络中的光谱兑换] ===<br />
<br />
频谱算法是流行的数据聚类方法。 但是,由于存在局部特征向量,它们在稀疏网络中经常失败。<br />
<br />
这篇在PNAS上与其他合作者一起发表的论文中,我们给出了一种基于非回溯算子的新频谱算法,该算子对这种疾病具有免疫力,并且在大型稀疏网络中非常有效。<br />
<br />
<br />
== 招募信息及联系方式 ==<br />
<br />
正在寻找统计物理学和机器学习领域的博士后研究人员<br />
<br />
电子邮箱:panzhang@itp.ac.cnn<br />
<br />
== 相关链接 ==<br />
<br />
1、[http://lib.itp.ac.cn/html/panzhang/ 张潘个人主页]<br />
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2、[https://scholar.google.com/citations?user=MFnbrRUAAAAJ&hl=en Google Scholar Profile 张潘谷歌学术主页]<br />
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[[Category:复杂系统]] <br />
[[Category:统计物理学]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%BC%97%E6%8B%89%E7%B1%B3%E5%B0%BC%E5%A5%A5_%E6%96%AF%E5%A4%B8%E4%BD%90%E5%B0%BC_Flaminio_Squazzoni&diff=15189
弗拉米尼奥 斯夸佐尼 Flaminio Squazzoni
2020-10-14T14:21:31Z
<p>Thingamabob:创建页面,内容为“ {{#seo: |keywords=squazzoni,弗拉米尼奥·斯夸佐尼,多主体模型,集智 |description=行为社会学,行为博弈论,JASSS,欧洲社会模拟协会,agent…”</p>
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{{#seo:<br />
|keywords=squazzoni,弗拉米尼奥·斯夸佐尼,多主体模型,集智<br />
|description=行为社会学,行为博弈论,JASSS,欧洲社会模拟协会,agent,peere,集智<br />
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该词条由 Pitorlin 翻译编辑,由高飞审校,张江总审校,翻译自[https://gecs.unibs.it/squazzoni.html squazzoni],另[http://behavelab.org/flaminio-squazzoni/ 参阅]。<br />
<br />
==基本信息==<br />
<br />
姓名:弗拉米尼奥·斯夸佐尼<br />
<br />
电话:+390250321017<br />
[[File:squazzoni.jpg|200px|thumb|right]]<br />
电子邮件:flaminio.squazzoni@unimi.it<br />
<br />
Twitter:@squazzoni<br />
<br />
<br />
==职位==<br />
米兰大学社会和政治科学系的社会学教授,也是行为实验室的主任。他为本科生讲授“社会学”,为硕士生讲授“行为社会学”,并为博士生讲授“行为博弈论”。直到2018年11月,他一直是布雷西亚大学经济与管理系经济社会学副教授,在那里他领导了 [http://www.gecs.unibs.it/ GECS实验与计算社会学研究小组]。<br />
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[http://jasss.soc.surrey.ac.uk/JASSS.html 《JASSS-人工社会与社会模拟杂志》]的编辑,[https://sociologica.unibo.it/ 《社会学》-《国际社会学辩论》]国际联合编辑,《[http://www.researchintegrityjournal.com/ 研究诚信与同行评议》]和[https://www.mulino.it/riviste/issn/1120-9550 《智能系统》]编辑委员会成员 。[http://eu.wiley.com/WileyCDA/Section/id-811877.html 计算与定量社会科学]的[http://eu.wiley.com/WileyCDA/Section/id-811877.html Wiley系列]和计算社会科学的[http://www.springer.com/series/11784 Springer系列]的顾问编辑, 并且是[https://www.thinkforwardinitiative.com/ ING(荷兰国际集团)ThinkForward Initiative]顾问委员会的成员。他是[http://www.essa.eu.org/ 欧洲社会模拟协会]的前任主席(2012年9月至2016年9月,自2010年起担任管理委员会成员)。曾任[http://www.nasp.eu/training/phd-programmes/esls.html NASP ESLS经济社会学与劳动研究博士项目]主任(2015-2016年)。<br />
<br />
==研究领域==<br />
他的研究领域是行为社会学,经济社会学和科学社会学,特别关注社会规范和制度对分散的大规模社会系统中合作的影响。他的研究方法并重于实验的(实验室)研究和计算的(基于主体的建模)研究。<br />
<br />
==文章著作==<br />
[https://onlinelibrary.wiley.com/doi/book/10.1002/9781119954200 《基于主体的计算社会学》]<br />
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[https://www.tandfonline.com/doi/full/10.1080/0022250X.2019.1704284 "当每个人都在争夺最强大的合作伙伴时,协作网络的团结:基于随机演员的仿真模型"]<br />
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[https://onlinelibrary.wiley.com/doi/abs/10.1002/psp.2263 相互隔离的自我。移民,社会背景和收入罚款]<br />
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==主持会议==<br />
[http://epos.unibs.it/ 第二次关于模拟的认识论观点国际研讨会EPOS(布雷西亚,2006年)]<br />
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[http://essa.unibs.it/ 欧洲社会模拟协会第五次会议(布雷西亚,2008年)]<br />
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[http://ecms.unibs.it/ 第28届ECMS-欧洲建模与模拟会议(布雷西亚,2014年)]<br />
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==项目==<br />
[http://www.peere.org/ peere同行审议]<br />
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[https://sociable.unibs.it/ Soipable-Brescia Nexus:人口老龄化中的社会基础设施和认知能力]<br />
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本词条内容翻译自gecs.unibs.it,遵守 CC3.0协议。<br />
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[[Category:多主体模型]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%B7%B4%E9%87%8C%C2%B7%E9%9F%A6%E5%B0%94%E6%9B%BC_Barry_Wellman&diff=15188
巴里·韦尔曼 Barry Wellman
2020-10-14T14:20:38Z
<p>Thingamabob:创建页面,内容为“== 基本信息 == 右 人物名:Barry Wellman(巴里 · 威尔曼)、 出生:1942年9月30日,美国纽约…”</p>
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<div>== 基本信息 ==<br />
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[[File:Barry-Wellman.png|缩略图|右]]<br />
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人物名:Barry Wellman(巴里 · 威尔曼)、<br />
出生:1942年9月30日,美国纽约布朗克斯<br />
国籍:加拿大裔美国籍<br />
母校:拉法耶特学院,哈佛大学<br />
研究方向:社交网络; 数字媒体;互联网与社会;网络工作;分布式工作<br />
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== 研究领域 ==<br />
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Barry Wellman 教授研究网络:社区、通信、计算机和社会。其研究检查了虚拟社区、虚拟工作场所、社会支持、社区、亲戚关系、友谊以及社交网络理论和方法。<br />
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==成就==<br />
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加拿大社会学和人类学协会、国际社交网络分析网、国际传播协会,GRAND 中心网络和美国社会学协会的两个部门——社区和城市社会学、通信和信息技术的职业成就奖。于2007年当选为加拿大皇家学会会员。<br />
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== 博士生导师 ==<br />
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Charles Tilly(查尔斯·堤利)<br />
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==学生==<br />
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Keith Hampton(基思 · 汉普顿)<br />
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Caroline Haythornthwaite(卡罗琳 · 海索恩斯怀特)<br />
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Anabel Quan-Haase(安娜贝尔 · 全 · 哈泽)<br />
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== 就职企业、机构或院校 ==<br />
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多伦多 NetLab 网络联合主任<br />
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新加坡国立大学传播与新媒体 Chong Yah 教授(2015)<br />
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多伦多大学社会学系 S.D. Clark 教授(2006-2011)<br />
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多伦多大学社会学系教授(1967-2013)<br />
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== 主要文章及著作 ==<br />
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===文章===<br />
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* [http://books.google.com/books?hl=en&lr=&id=XIw4AAAAIAAJ&oi=fnd&pg=PR7&dq=info:dGOynanZeSsJ:scholar.google.com&ots=Mr3WOkSVJZ&sig=mG1FDa5oFFl8UOPKmhxf7tvv5bs接 Social structures: A network approach] 《社会结构:一种网络方法》 B Wellman, SD Berkowitz,CUP Archive,1998,被引3370次<br />
* [https://www.journals.uchicago.edu/doi/abs/10.1086/229572 Different strokes from different folks: Community ties and social support] 《各人有各法:社区联系与社会支持》 B Wellman, S Wortley,《美国社会学期刊》 96 (3), 558-588,1990,被引2393次<br />
* [https://www.journals.uchicago.edu/doi/abs/10.1086/226906 The community question: The intimate networks of East Yorkers] 《社区问题:东纽约人的亲密网络》 B Wellman,《美国社会学期刊》 84 (5), 1201-1231,1979,被引2328次<br />
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===著作===<br />
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麻省理工学院出版社于2012年春季出版其与皮尤网络和美国生活项目(Pew Internet and American Life Project)总监李 · 雷尼(Lee Rainie)合著的屡获殊荣的《网络化:新的社会操作系统》(Networked: The New Social Operating System)一书。该书分析了源于社交网络革命、互联网革命和移动革命的网络化个人主义的自然属性。<br />
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== 研究课题 ==<br />
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===社区社会学===<br />
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直到1990年,韦尔曼主要关注社区社会学和社会网络分析。在多伦多的前三年,他还在克拉克精神病研究所(Clarke Institute of Psychiatry)联合兼职,在那里他与 D.B. 科茨(D.B. Coates)医学博士共同指导了东约克多伦多自治市的“约克研究(Yorkles Study)”。这是东约克的第一项研究,其数据收集于1968年,试图对大量人群进行实地研究,将人际关系与精神病症状联系起来。 这项关于”社会支持”的早期研究记录了非本地友谊和亲属关系的普遍存在,表明社区不再局限于邻里,并将非本地社区作为社会网络加以研究。韦尔曼基于此研究的“社区问题”论文被选为英国-加拿大社会学七篇最重要的论文之一。<br />
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1978年至1979年,多伦多大学城市与社区研究中心进行了第二项东约克研究,通过对33名(最初是在第一项研究中调查过的)东约克人进行深度访谈 ,深入了解他们社交网络。 该研究有力说明了何种关系和网络提供了何种类型的社会支持。 例如,研究表明,姐妹在兄弟姐妹中提供了很多情感支持,而父母则提供经济援助。 这种支持更多地来自于关系的特性,而不是它们所嵌入的网络。 这项研究还表明,妻子不仅为自己,也为丈夫维持着社会关系网。<br />
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虽然韦尔曼的工作已经主要转移到互联网研究(见下面一节) ,但他也继续对东约克第一、二项研究进行协作分析。结果表明,相互关系(如社会支持)与其说是一种社会网络现象,不如说是一种联系现象,而且在互联网出现之前,人际交往的频率和支持性与居住(和工作场所)距离间的联系是非线性的。 <br />
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韦尔曼编辑了《地球村的网络》(Networks in the Global Village, 1999) ,这是一本关于世界各地个人网络的原创文章集。 2007年,他主编了《社交网络》(Social Networks, vol. 29, no. 3, July)杂志的特刊"网络是个人的"。文内包含来自加拿大、法国、德国和伊朗的分析。<br />
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===社会网络理论===<br />
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实证工作之外,威尔曼对社会网络分析理论也做出了贡献。 最全面的陈述发表在他与已故的 S.D. 伯科威(S.D.Berkowitz)共同编辑的《社会结构》(Social Structures)的介绍性文章中。 这项工作回顾了社会网络思想的历史,并提出了一些社会网络分析的基本原则。<br />
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最近和更集中的理论工作讨论了当代社区的“全球化”(同时”全球化”和”地方化”)以及”网络个人主义”的兴起——从基于群体的网络向个性化网络的转变。 美国社会学协会职业成就奖获得者哈里森·怀特(Harrison White)指出: “ 巴里 · 韦尔曼的整个学术生涯都致力于用网络的方式探索和记录自然社会世界。”<br />
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===社交网络方法===<br />
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韦尔曼的方法论贡献在于分析以自我为中心或“个人”网络——从个体(通常是个人)的角度来定义。 由于人们经常研究成批的个人网络,这需要一些不同于更常见的分析单个大型网络的社会网络实践技术。<br />
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2007年,韦尔曼(与伯尼 · 霍根(Bernie Hogan)和胡安 - 安东尼奥 · 卡拉斯科(Juan-Antonio Carrasco))合著了一篇论文,讨论了收集个人网络数据的替代方案。与肯尼思 · 弗兰克(Kenneth Frank)的一篇论文展示了如何解决同时分析关系和网络两个不同层次上的个人网络数据的问题。 《Neighboring in Netville》被引用为对来自已知的潜在网络成员名单的个人网络的唯一公开研究。 被引用最多的论文是最简单的:与人共同编写的使用统计软件包 SAS 和 SPSS 时分析个人网络数据的指南。<br />
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韦尔曼和霍华德 · D · 怀特(Howard D. White)及其同事的其他工作已经研究了如何将社会网络分析与引文网络的科学计量学研究联系起来。这项研究表明,学术界的朋友并不一定引用彼此的文章,但是同一篇文章中引用的学者倾向于互相寻找并成为朋友。<br />
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===互联网、科技与社会===<br />
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韦尔曼经常与计算机科学家、通信科学家和信息科学家合作。1990年,他参与研究普通人如何利用互联网和其他通信技术在工作场所、家庭和社区交流和交换信息。因此,他的工作拓展了他对非本地社区和社会网络的兴趣,包括互联网、移动电话和其他信息与通信技术。<br />
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====工作网络和信通技术====<br />
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韦尔曼最初的项目(”山猫(Cavecat)”后来演变成“远程呈现(Telepresence)”)是与罗纳德 · 贝克(Ronald Baecker)、卡罗琳·海索恩斯怀特(Caroline Haythornthwaite)、玛丽莲 · 曼特(Marilyn Mantei)、盖尔 · 摩尔(Gale Moore)和珍妮特 · 萨拉夫(Janet Salaff)合作完成的。 这项工作在20世纪90年代早期完成,当时互联网还没有普及,使用联网的个人电脑进行视频会议和计算机支持的协同工作(CSCW)。 卡罗琳·海索恩斯怀特(Caroline Haythornthwaite)(为了她的论文和其他工作)和韦尔曼分析了为什么计算机科学家之间会有联系——在线和离线。他们发现,友谊和协作是工作中联系的主要推动者。<br />
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韦尔曼和安娜贝尔 · 全 · 哈泽(Anabel Quan-Haase)还研究了这种计算机支持的工作团队是否支持并不看重官僚结构和物理接近性的网络化组织。 他们对一个高科技的美国组织——严重依赖即时通讯和电子邮件——的研究表明,所谓的由信息通信技术驱动的工作向网络化组织的转变在实践中只完成了一部分。 部门组织的组织约束(包括权力)和物理接近继续发挥重要作用。 当使用不同的传播媒介时,组织中有很强的规范,面对面的接触和在线接触交织在一起。<br />
<br />
韦尔曼与迪米特里娜·迪米特罗娃(Dimitrina Dimitrova),Tsahi Hayat,和 Guang Ying Mo 合作,在加拿大多个研究中心对140名网络学者进行了 NAVEL 研究。 他们发现,尽管强调网络,学科和空间界限继续影响谁与谁互动。<br />
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====社区网络和信通技术====<br />
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作为一个社区的社会学家,韦尔曼开始争辩说,太多的网络生活分析是孤立于日常生活的其他方面的。 他(单独或协作)发表了几篇论文,认为有必要将互联网研究置于背景之中,并提出,最好将在线关系(如离线关系)作为分支的社会网络而不是有限的群体来研究。这一争论在2002年的《日常生活中的互联网》一书(与卡罗琳·海索恩斯怀特(Caroline Haythornthwaite)合著)中达到了高潮 ,该书提供了一些社会学研究的例证。<br />
<br />
韦尔曼在这个领域做了实证研究:他是由詹姆斯 · 威特(James Witte)领导的团队的一员,该团队在1998年调查了访问国家地理学会网站的访问者,并利用这些数据反驳了互联网的参与与社会隔离有关的反乌托邦观点。<br />
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皮尤互联网报告《互联网关系的力量》(The Strength of Internet Ties)(由杰弗里 · 博斯(Jeffrey Boase)、约翰 · B · 霍里根(John B. Horrigan)和李 · 雷尼(Lee Rainie)联合撰写)中分析的大规模美国全国随机抽样调查也显示,网络交流、电话交流和面对面交流之间存在正相关关系。这项研究表明,电子邮件非常适合与大型社交网络保持定期联系,尤其是对那些只有一定强度的关系来说。研究还发现,互联网用户比非互联网用户从朋友和亲戚那里得到更多的帮助。<br />
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对“全球本土化”概念的研究也被纳入了这一知识流。 基思 · 汉普顿(Keith Hampton)和韦尔曼研究了多伦多郊区的“内维尔(Netville)”(化名)。它展示了在线和离线活动之间的相互作用,以及互联网——在列表服务的帮助下——不仅是一种远程交流的手段,而且增强了邻里关系和公民的参与。<br />
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他与世界互联网项目数字未来中心的 Helen Hua Wang 和杰弗里·科尔(Jeffrey Cole)合作,开展了美国第一个关于社会关系和互联网使用的全国性调查。他们的研究表明,人均朋友数量正在增加,而且重度互联网用户的朋友比其他人更多。 韦尔曼还与本 · 温霍夫(Ben Veenhof)(加拿大统计局)、卡斯滕 · 奎尔(Carsten Quell)(加拿大文化遗产局)和伯尼 · 霍根(Bernie Hogan)合作,把在家里上网的时间与社会关系和公民参与联系起来。此外他还与 Wenhong Chen 合作研究连接中国和北美的跨国移民企业家。<br />
<br />
韦尔曼的工作继续侧重于信息和通信技术之间的相互作用,特别是互联网、社会关系和社会结构。 他在多伦多和安大略省北部农村的查普洛指导了一项关于沟通、社区和家庭关系之间相互作用的关联生活(Connected Lives)研究。 关于在线和离线生活之间相互作用的早期发现在“连接的生活: 项目(Connected Lives: The Project)”中有所总结。 更为集中的研究(与珍妮弗(Jennifer Kayahara)合作)阐述了曾经的两级传播如何因互联网对信息搜索和交流的促进变为更为递归的多步式。(与特雷西 · 肯尼迪(Tracy Kennedy)合作的)研究认为,如社区一样,许多家庭已经从本地群体转变为通过频繁的信息通信技术和移动电话通信连接起来的空间分散的网络。网络实验室的其他研究人员,除了正文和笔记中提到的人,还包括朱莉 · 阿莫罗索(Julie Amoroso)、克里斯蒂安 · 比尔曼(Christian Beermann)、迪安 · 贝伦斯(Dean Behrens)、文森特 · 蔡美儿(Vincent Chua)、杰西卡 · 柯林斯(Jessica Collins)、迪米特洛娃(Dimitrina Dimitrova)、扎克 · 海亚特(Zack Hayat)、Chang Lin、朱莉娅 · 马德伊(Julia Madej)、玛丽亚 · 马耶斯基(Maria Majerski)、Mo Guang Ying、戴安娜 · 莫克(Diana Mok)、巴尔巴拉 · 内维斯(Bárbara Barbosa Neves)和莉莉娅 · 斯梅尔(Lilia Smale)。<br />
<br />
韦尔曼参与了“网络个人”项目,利用第四次东约克研究调查他们的社交网络和数字媒体的使用。 他的合作者包括布伦特·贝里(Brent Berry)、玛丽亚·基切夫斯基(Maria kicheveski)、Guang Ying Mo、安娜贝尔 · 全 · 哈泽(Anabel Quan-Haase)、Helen Hua Wang 和 Alice Renwen Zhang。 最初的论文聚焦于65岁以上的老年人,展示了他们如何使用数字媒体与远近亲属保持联系。<br />
<br />
== 近期报道 ==<br />
<br />
[https://semioticon.com/sx-old-issues/semiotix14/sem-14-05.html The Networked Individual: A Profile of Barry Wellman],网络化的个体:巴里 · 韦尔曼传简介,伯尼 · 霍根(Bernie Hogan)(Barry Wellman 的学生),2009年1月<br />
<br />
== 联系方式 ==<br />
<br />
* 电子邮件:wellman@chass.utoronto.ca<br />
* 电话:(416)884-3052<br />
* 网站:http : //groups.chass.utoronto.ca/netlab/barry-wellman/<br />
<br />
== 相关链接 ==<br />
<br />
=== 视频 ===<br />
<br />
[https://www.baidu.com/link?url=jZkZUXCtKRd6FYlPuI85dLZEjzcmK_q4GAfuJg5tsGkrvCGeMkL0zClKHrbVnFGafKZIjq6z158bP_wdzGZ1MK&wd=&eqid=831b625c0019ce09000000025e19cb1f 多伦多大学社会学巴里·威尔曼教授采访视频_腾讯视频]:<br />
<br />
=== 更多信息 ===<br />
<br />
[https://uttri.utoronto.ca/people/barry-wellman/ 个人主页] <br />
<br />
[https://en.wikipedia.org/wiki/Barry_Wellman wiki词条]<br />
<br />
[[Category:网络科学]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%B0%BC%E7%89%B9%E6%96%BD%C2%B7%E8%80%83%E6%8B%89_Nitesh_V_Chawla&diff=15186
尼特施·考拉 Nitesh V Chawla
2020-10-14T14:20:02Z
<p>Thingamabob:创建页面,内容为“== 基本信息 == 右 姓名:Nitesh V Chawla(尼特施·考拉) 居住地:印第安纳州圣母院 学位…”</p>
<hr />
<div>== 基本信息 ==<br />
<br />
[[File:Nitesh V Chawla.jpeg|缩略图|右]]<br />
<br />
姓名:Nitesh V Chawla(尼特施·考拉)<br />
居住地:印第安纳州圣母院<br />
学位:1997年获波那大学计算机科学与工程学士;2000年获南佛罗里达大学计算机科学硕士;2002年获南佛罗里达大学计算机科学与工程博士学位,<br />
研究方向:广泛地涉及大数据领域:数据科学,机器学习,网络科学及其应用,社交网络,医疗保健信息学/分析学和气候/环境科学<br />
<br />
== 研究领域及荣誉 ==<br />
<br />
其研究重点是机器学习,数据科学和网络科学。他在跨学科应用领域处于前沿,并在医疗保健分析,社会和信息网络,业务分析,国家安全以及气候/环境科学领域开展创新工作。曾多次获得研究和教学创新奖,包括杰出教师奖(2007年和2010年),美国国家工程师学会新教师奖学金,2015年IEEE CIS杰出早期职业奖的获得者;IBM沃森学院奖,IBM大数据与分析学院奖,美国国家工程院新学院奖学金,其博士学位论文也获得了杰出论文奖。由于其研究对社会和社区的影响,获得了Rodney Ganey奖和Michiana 40 Under40。 Reilly科学,技术和价值中心研究员;亚洲研究所研究员和亚洲研究;巴黎圣母院Kroc国际和平研究所研究员,数据科学公司Aunalytics的创始人。<br />
<br />
== 学生 ==<br />
<br />
* [https://engineering.nd.edu/profiles/wdaheng Wang Daheng]<br />
* [https://engineering.nd.edu/profiles/lfaust Louis Faust]<br />
* [https://engineering.nd.edu/profiles/slin2 Suwen Lin]<br />
* [https://engineering.nd.edu/profiles/jmarshal Jermaine Marshall]<br />
* [https://engineering.nd.edu/profiles/jschnur Mandana Saebi]<br />
* [https://engineering.nd.edu/profiles/jschnur Jennifer Schnur]<br />
* [https://engineering.nd.edu/profiles/msyed Munira Syed]<br />
* [https://engineering.nd.edu/profiles/ptang Pingjie Tang]<br />
* [https://engineering.nd.edu/profiles/xwu3 Xian Wu]<br />
* [https://engineering.nd.edu/profiles/czhang3 Chuxu Zhang]<br />
<br />
== 就职企业、机构或院校 ==<br />
<br />
=== DIAL ===<br />
<br />
在Chawla教授的指导下,工程学院的DIAL(数据,推理分析和学习)实验室专注于机器学习,人工智能,网络科学和大数据。<br />
<br />
=== ICENSA ===<br />
<br />
iCeNSA由Chawla教授领导,是一家多学科的大学研究院,围绕社会,生物,生化,物理,环境,金融,组织,技术和国防系统中的网络和数据科学问题而组织。<br />
<br />
作为研究中心,iCeNSA(1)对复杂网络的结构,动力学和功能特性背后的基本过程和机制进行系统级的理解,(2)为网络科学开发和集成新颖的数学和计算工具。<br />
<br />
== 主要文章及著作 ==<br />
<br />
* [http://www.jair.org/papers/paper953.html SMOTE: synthetic minority over-sampling technique]2002,被引9357次<br />
<br />
* [https://dlacm.xilesou.top/citation.cfm?id=1007733 Special issue on learning from imbalanced data sets] 2004,被引1753次<br />
<br />
*[https://link.springer.xilesou.top/chapter/10.1007/978-3-540-39804-2_12 SMOTEBoost: Improving prediction of the minority class in boosting] 2003,被引1160次<br />
<br />
== 近期报道 ==<br />
<br />
===[https://cse.nd.edu/news/notre-dame-saint-mary2019s-to-expand-data-science-programs-with-ethics-social-responsibility-components 圣母院(Notre Dame),圣玛丽(Saint Mary's)扩展具有道德,社会责任成分的数据科学计划]===<br />
圣母大学和圣玛丽学院获得了超过110万美元的资金,用于通过“社会责任与参与数据科学”跨学科培训项目扩展数据科学教育。<br />
<br />
===[https://cse.nd.edu/news/your-circle-of-friends-not-your-fitbit-is-more-predictive-of-your-health 您的朋友圈而非Fitbit更能预测您的健康状况]===<br />
在弗兰克·弗赖曼(Frank M. Freimann)教授尼特什·乔瓦(Nitesh Chawla)的带领下,圣母大学的研究人员研究了社交网络的结构以及他们对个人健康,幸福和压力状况的评价。<br />
<br />
===[https://engineering.nd.edu/news-publications/pressreleases/women-your-inner-circle-may-be-key-to-gaining-leadership-roles 女人,你的内心圈子可能是获得领导角色的关键]===<br />
根据圣母大学和西北大学的一项新研究,与女性主导的内圈定期进行交流的女性更有可能获得高级领导职位。<br />
<br />
== 联系方式 ==<br />
<br />
* 电子邮件: nchawla@nd.edu<br />
* 电话: 574-631-1090<br />
* 办公室:纽埃兰科学馆384<br />
<br />
== 相关链接 ==<br />
<br />
[https://scholar.google.com/citations?user=hDLBEhkAAAAJ&hl=zh-CN 谷歌学术]<br />
<br />
[https://engineering.nd.edu/profiles/nchawla 个人主页]<br />
<br />
[https://www3.nd.edu/~nchawla/ 个人主页]<br />
<br />
[[Category:网络科学]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%B0%A4%E6%A0%B9%C2%B7%E5%BA%93%E6%80%9D_J%C3%BCrgen_Kurths&diff=15185
尤根·库思 Jürgen Kurths
2020-10-14T14:19:42Z
<p>Thingamabob:创建页面,内容为“ {{#seo: |keywords=尤根·库思,Jurgen Kurths 复杂系统的非线性物理 集智 |description=尤根·库思,Jurgen Kurths 复杂系统的非线性物理…”</p>
<hr />
<div><br />
{{#seo:<br />
|keywords=尤根·库思,Jurgen Kurths 复杂系统的非线性物理 集智<br />
|description=尤根·库思,Jurgen Kurths 复杂系统的非线性物理 集智<br />
}}<br />
<br />
== 基本信息 ==<br />
[[File:Jurgen.jpeg|225px|left]]<br />
{| class="wikitable"<br />
|-<br />
! 类别 !! 信息<br />
|-<br />
|姓名:|| 尤根·库思 Jürgen Kurths<br />
|-<br />
|国籍:|| 德国<br />
|-<br />
|出生日期:|| 1953年3月11日<br />
|-<br />
|母校:||德国罗斯托克大学 University of Rostock<br />
|-<br />
|成就:|| 复杂系统<br />
|-<br />
| 所在机构: || 波茨坦气候影响研究所 Potsdam Institute for Climate Impact Research 、柏林洪堡大学 Humboldt University 物理学院<br />
|-<br />
| 研究方向:||复杂系统的非线性物理<br />
|-<br />
|个人主页链接||[https://www.pik-potsdam.de/members/kurths 尤根·库思]<br />
|-<br />
| 所在城市: || 德国<br />
|-<br />
| 联系方式: || 电话 +49-331 288-2647 传真 +49-331 288-2600 电子邮件 Juergen.Kurths@pik-potsdam.de<br />
<br />
|}<br />
<br />
<br /><br />
<br />
== 其他信息 ==<br />
===个人传记===<br />
<br />
'''尤根·库思 Jürgen Kurths''' 是一名出生于德国阿伦德塞的物理学家和数学家。他在'''波茨坦气候影响研究所 Potsdam Institute for Climate Impact Research''' 主管跨学科概念与方法的研究领域,同时也是'''柏林洪堡大学 Humboldt University''' 物理学院非线性动力学的正教授,他还在'''英国阿伯丁大学Aberdeen University''' 国王学院的复杂系统和数学生物研究所担任复杂系统生物学的第六任世纪主席。作为一位在复杂系统的非线性物理领域的知名专家,他在非线性动力学、复杂性科学和复杂网络以及在气候学、生理学、系统生物学和工程学的应用方面颇有建树。<br />
<br />
=== 研究经历 ===<br />
Jurgen Kurths曾在'''德国罗斯托克大学 University of Rostock''' 主攻数学,于1983年在'''民主德国科学院 German Academy of Sciences at Berlin''' 获得了博士学位,并于1991年在德国罗斯托克大学获得了理论物理特许任教的资格。<br />
<br />
<br />
1991年,在'''马克斯·普朗克学会 Max-Planck-society''' 上,Jurgen Kurths 从来自东德的少数科学家中脱颖而出,成为一个新的非线性动力学领域研究工作组的领导者,如今它已经成为了一个国际知名的、享有很高声誉的研究组。<br />
<br />
<br />
1994年,Jurgen Kurths 成为'''德国波茨坦大学 University of Potsdam''' 理论物理/非线性动力学的首席正教授,于1996-1999年任'''波茨坦大学科学学院 University of Potsdam School of Science''' 院长,并建立了一个非常具有影响力的复杂系统动力学的跨学科研究中心(1994-2008年)。<br />
<br />
<br />
同时,他也是[https://www.leibnizkollegpotsdam.de/nc/index.html 波茨坦Leibniz-Kolleg]的创始人 。2008年,他受命于波茨坦气候影响研究所的跨学科部门(RD-IV),把复杂系统的研究思想理念引入地球系统的研究中,并且成为柏林洪堡大学物理学院非线性动力学的正教授。 此外,他还是德国波茨坦大学的名誉教授和中国'''东南大学 Southeast University''' 的客座教授;从1999年起,他还在英国阿伯丁大学国王学院的复杂系统和数学生物研究所担任复杂系统生物学的第六任世纪主席。<br />
<br />
==研究领域==<br />
[[File:jurgen_kurths.jpg.225x225_q90_crop_target-69,48_upscale_zoom-99_2x.jpg|300px|right]]<br />
Jurgen Kurths 对地球科学非线性过程领域的贡献是多种多样的,并且具有很高的独创性,他的工作对该领域产生了重大影响。他开发了非线性时间序列分析中的重要新方法,例如同步和递归分析,还为其他研究问题做出了重要贡献,例如人脑中的同步过程。Jurgen Kurths在耦合混沌振荡器同步方面的工作已导致相位同步和滞后同步在振荡器网络分析中得到广泛应用,而他在相干共振方面的工作大大提高了我们对共振的总体理解。<br />
<br />
<br />
在非线性数据分析中,他介绍了基于递归的复杂性度量,以及递归网络和网络网络的研究和特征描述。这些想法和方法打开了理论研究的新分支,并触发了在地球科学和可持续性方面的关键应用。如今,他和他的合作者发现的现象和所介绍的方法已包含在几本教科书中。Jurgen Kurths的强大优势在于将现代数学方法与非线性过程领域的广泛兴趣相结合。他和他的小组最近已将复杂网络理论应用于气候的成熟度很高。他对循环和同步的研究有助于阐明主要气候过程之间的关系,例如印度季风,厄尔尼诺-南方涛动和北大西洋涛动。在他从事和影响的地球科学领域中,有一些基于地球岩石圈非线性系统的地震预测研究。库尔斯著作的一个特征是在远离产生最初思想的学科的领域中被引用,这一特征与理查森本人的著作相同。<br />
<br />
=== 获奖经历 ===<br />
<br />
<br />
<br />
*2000年,曾当选'''美国物理学会 American Physical Society''' 和'''弗劳恩霍夫协会 Fraunhofer Society''' 的院士;<br />
*2005年,获印度科学与工业研究理事会的'''亚历山大·洪堡研究奖 Alexander von Humboldt Research Award''' ;<br />
*2008年,获'''诺夫哥罗德大学 Lobachevsky University in Nizhny Novgorod''' 和'''萨拉托夫国立大学 Chernishevsky University''' 荣誉博士学位 ;<br />
*2010年,成为欧洲科学院成员<br />
*2011年,成为波茨坦大学名誉教授<br />
*2012年,成为东南大学客座教授,南京<br />
*2012年,获萨拉托夫州立大学名誉博士学位<br />
*2012年,成为'''马其顿科学艺术院 Macedonian Academy of Sciences and Arts'''的院士;<br />
*2013年,获欧洲地球科学联盟的刘易斯·弗莱·理查森勋章,,以表彰他在耦合混沌振荡器的同步和递归网络中的关键新概念和工具的开发,以及它们在气候动力学和非线性地球科学中的创新应用<br />
*2015年,成为汉堡大学客座教授和汉堡讲座<br />
*2017年,成为阿伯丁大学国王学院名誉教授<br />
*2018年,成为天津大学名誉教授(中国)<br />
*2018年,成为中国厦门华侨大学名誉教授<br />
<br />
<br />
<br />
<br />
=== 学术影响力 ===<br />
<br />
起初Jurgen Kurths研究时间序列分析及其在太阳活动现象上的应用,80年代起他的研究兴趣转向了复杂系统学、非线性科学和混沌理论,开始从事复杂系统理论及其在地球系统、人体大脑和其它高度复杂、非线性系统中应用的研究。 <br />
<br />
Jurgen Kurths在发展学术研究活动方面成绩显著,在非线性动力学和复杂网络的国际化和跨学科发展中充当了重要角色。在他的带领下,研究组在同步、涌现、复杂网络、非线性时间序列分析及在地球科学、认知心理学、生物学、医学和工程等领域的应用方面取得了重要的理论突破。<br />
<br />
此外,他还拥有一个大型科学合作网络平台,共培养出60多位来自20多个国家的博士研究生,其中有30人已在不同国家获得了终身教授职位。<br />
<br />
<br />
<br />
=== 参加和组织活动 ===<br />
Jurgen Kurths已经成为许多国际科学活动的领导者,例如,他曾于2000-2005年主管'''欧洲地球科学联盟 European Geosciences Union''' 的非线性过程地球科学部。他努力促进国际合作,并在欧盟和德国研究基金会举办了多个大型项目,是复杂网络国际研究训练组德国和巴西科学研究基金会的发言人。<br />
<br />
== 主要文章及著作 ==<br />
=== 发表文章 ===<br />
* Michael G Rosenblum, Arkady S Pikovsky, Jürgen Kurths, [https://www.researchgate.net/profile/Juergen_Kurths/publication/13229082_Phase_Synchronization_of_Chaotic_Oscillators/links/54900c300cf214269f264a0f/Phase-Synchronization-of-Chaotic-Oscillators.pdf Phase synchronization of chaotic oscillators](混沌振荡器的相位同步), Physical review letters,Pages:1804(1996/3/11,引用次数:2934):本文提出了弱耦合自持混沌振荡器(weakly coupled self-sustained chaotic oscillators)的相位同步的新效果。 为了表征这种现象,该文使用基于希尔伯特变换(the Hilbert transform)和局部庞加莱图(partial Poincaré maps)的解析信号方法。 <br />
* Alex Arenas, Albert Díaz-Guilera, Jürgen Kurths, Yamir Moreno, Changsong Zhou, [https://arxiv.org/pdf/0805.2976.pdf Synchronization in complex networks](复杂网络中的同步), Physics reports,Pages:93-153(2008/12/1,引用次数:2659):该文是一篇综述性文章,报告了在复杂的网络拓扑中,当振荡元素受到约束时,在理解同步现象方面的进展。<br />
* Stefano Boccaletti, Jürgen Kurths, Grigory Osipov, DL Valladares, CS Zhou, [http://engineering.nyu.edu/mechatronics/Control_Lab/bck/VKapila/Chaotic%20Ref/Porfiri's/share/scaricati-09-28-2007/boccoletti.pdf The synchronization of chaotic systems](混沌系统的同步), Physics reports,Pages:1-101(2002/8/1,引用次数:2594):本文回顾了在混沌系统同步领域中涉及的主要思想,并详细介绍了几种类型的同步功能:完全同步(complete synchronization),滞后同步(lag synchronization),广义同步(generalized synchronization),相位和不完美相位同步(phase and imperfect phase synchronization)。<br />
* Norbert Marwan, M Carmen Romano, Marco Thiel, Jürgen Kurths, [https://s3.amazonaws.com/academia.edu.documents/32053423/Recurrence_Plots_for_the_analysis_of_complex_systems__Norbert_Marwin_etal.pdf?response-content-disposition=inline%3B%20filename%3DRecurrence_Plots_for_the_analysis_of_com.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20191025%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20191025T023026Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=4442b1d70fa4ae4e60999ccb5aed6683c394cfea18446fa8b32ee5548639e8a8 Recurrence plots for the analysis of complex systems](用于分析复杂系统的递归图), Cambridge university press,Pages:237-359(2007/1/1,引用次数:2409):本文是一个全面的总结,涵盖了基于递归的方法及其应用,并重点介绍了最新的发展。在简要了介绍递归理论之后,还介绍了递归图及其变化的基本思想。最后讲述了了重复图在经济,生理学,神经科学,地球科学,天体物理学和工程学中的几种应用。本文的目的是向读者介绍如何在自己的研究领域中应用基于重复图的方法。<br />
=== 出版书籍 ===<br />
[http://www.scholarpedia.org/article/Synchronized Synchronization: a universal concept in nonlinear sciences](同步:非线性科学中的通用概念)<br />
* 该书由剑桥大学出版社于2003/4/24出版,引用次数:8029,Arkady Pikovsky, Jürgen Kurths, Michael Rosenblum著。本书的前半部分描述了不带公式的同步(Synchronization),并且基于定性的直观思想。通过实验实例和数字说明主要效果,并概述其历史发展。该书的其余部分以一种严格而系统的方式介绍了同步的主要作用,描述了有关周期振荡器同步的经典结果,以及混沌系统,大型合奏和振荡介质的最新发展。<br />
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===参与期刊===<br />
尤根·库思发表了500余篇学术论文和出版了8部著作。目前,他担任了10余个科学期刊的编委,其中包括:CHAOS、Philosoph.Trans、Royal Soc. A、 PLoS ONE、 Europ. J. Physics ST、J. Nonlinear Science and Nonlinear Processes in Geophysics 和 Springer Series Complexity等,下为详细介绍。<br />
<br />
*2000-2011年 '''分叉与混乱 Int. Journal Bifurcation & Chaos'''<br />
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*自2012年起 Int. J. Bif.&Chaos荣誉委员会委员<br />
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*自2003年以来 '''施普林格复杂性系统 Springer Series of Complexity'''<br />
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*自2005年以来 '''地球物理学中的非线性过程 Nonlinear Processes in Geophysics''' ,执行编辑<br />
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*2008-2013 '''英国皇家学会哲学学报A:数学,物理和工程科学 Philosophical Transaction of the Royal Society A: Mathematical, Physical and Engineering Sciences'''<br />
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*自2009年以来 '''欧洲期刊物理,专题 European Journal Physics, Special Topics'''<br />
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*自2012年起 '''欧洲期刊物理学,非线性生物医学物理 European Journal Physics, Nonlinear Biomedical Physics<br />
'''<br />
*自2015年以来 '''欧洲物理学快报 Europhysics Letters'''<br />
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*自2016年以来 CHAOS,总编辑<br />
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*自2017年以来 '''AIMS地球科学 AIMS Geosciences'''<br />
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*自2017年以来 '''先进理论与模拟 Advanced Theory and Simulations'''<br />
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===近期发表论文===<br />
*[https://dblp.uni-trier.de/db/journals/complexity/complexity2020.html#JiZLLK20 基于价格的频率调节如何影响电网的稳定性:复杂网络视角]<br />
*[https://dblp.uni-trier.de/db/journals/complexity/complexity2020.html#SunLKZ20 具有干扰的多智能体系统的固定时间连接保持跟踪共识]<br />
*[https://www.nature.com/articles/s41561-019-0312-z 热带植被受降雨量变化的影响]<br />
*[https://www.nature.com/articles/s41586-018-0872-x 复杂的网络揭示极端降雨遥相关的全球模式]<br />
*[https://www.pik-potsdam.de/members/kurths/recent-selected-publications/copy2_of_Rodriguesetal.2016.pdf 复杂网络中的Kuramoto模型]<br />
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== 联系方式 ==<br />
=== 办公地点 ===<br />
* 地址:Till Hollmann<br />
* 电话: +49-331-288-2470<br />
* 电子邮箱: hollmann@pik-potsdam.de<br />
=== 其他地址 ===<br />
* 地址:Telegrafenberg A31 14473 Potsdam<br />
* 电话: +49-331 288-2647<br />
* 传真: +49-331 288-2600<br />
* 电子邮箱: Juergen.Kurths@pik-potsdam.de<br />
== 相关链接 ==<br />
1、[https://zh.wikipedia.org/wiki/%E5%B0%A4%E6%A0%B9%C2%B7%E5%BA%93%E6%80%9D wiki个人词条]<br />
<br />
2、[https://www.pik-potsdam.de/members/kurths 波茨坦气候影响研究所人物页]<br />
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3、[https://scholar.google.com/citations?hl=zh-CN&user=iwzqdyQAAAAJ 谷歌学术页]<br />
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本词条内容源自wikipedia及公开资料,遵守 CC3.0协议。<br />
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[[category:复杂系统]]<br />
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[[category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A5%88%E6%9D%B0%E5%B0%94%C2%B7%E5%90%89%E5%B0%94%E4%BC%AF%E7%89%B9_Nigel_Gilbert&diff=15183
奈杰尔·吉尔伯特 Nigel Gilbert
2020-10-14T14:18:27Z
<p>Thingamabob:创建页面,内容为“ {{#seo: |keywords=杰弗里·尼格尔·吉尔伯特,多主体模型,计算社会科学,集智 |description=剑桥大学,计算社会学,复杂理论,科学社会…”</p>
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<div><br />
{{#seo:<br />
|keywords=杰弗里·尼格尔·吉尔伯特,多主体模型,计算社会科学,集智<br />
|description=剑桥大学,计算社会学,复杂理论,科学社会学,科学知识社会学,JASSS,社会学研究在线,集智<br />
}}<br />
该词条由 Pitorlin 翻译编辑,由高飞审校,张江总审校,翻译自Wikipedia词条[https://en.wikipedia.org/wiki/Nigel_Gilbert Nigel_Gilbert],另[https://www.surrey.ac.uk/people/nigel-gilbert 参阅]。<br />
<br />
杰弗里·尼格尔·吉尔伯特 [https://en.wikipedia.org/wiki/Commander_of_the_Order_of_the_British_Empire CBE] [https://en.wikipedia.org/wiki/Fellow_of_the_British_Computer_Society FBCS] [https://en.wikipedia.org/wiki/Fellow_of_the_Royal_Society_of_Arts FRSA] [https://en.wikipedia.org/wiki/Fellow_of_the_Academy_of_Social_Sciences FAcSS] [https://en.wikipedia.org/wiki/Fellow_of_the_Royal_Academy_of_Engineering FREng](1950年出生3月21日)英国社会学家和将[https://en.wikipedia.org/wiki/Agent-based_model 基于主体的模型]运用于社会科学的先驱。他是萨里大学(University of Surrey)社会模拟研究中心的创始人和主任,曾发表过几本关于计算社会科学、社会模拟和社会研究的书籍,并且是该领域前沿期刊[https://en.wikipedia.org/wiki/Journal_of_Artificial_Societies_and_Social_Simulation 人工社会和社会模拟杂志](JASSS)的编辑。<br />
[[File:NigelGilbert.jpg|200px|thumb|left]]<br />
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国籍:英国<br />
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母校:剑桥大学<br />
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领域:计算社会学 复杂理论 科学社会学<br />
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博士生导师:迈克尔·穆凯<br />
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==职业==<br />
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他是剑桥大学工程学毕业生(以马内利学院),在迈克尔·穆尔凯(Michael Mulkay)的指导下,他转向科学知识社会学的博士学位。他曾在约克大学任教(1974–76年),然后加入萨里大学,于1991年成为社会学系教授。1984年,在[https://en.wikipedia.org/wiki/Alvey_Programme Alvey计划]的资助下,他在萨里大学建立了社会与计算机科学研究小组。该小组致力于将社会科学应用于基于知识的智能系统的设计。后来,他成立了社会模拟研究中心(1997年)和数字世界研究中心(1998)。他曾任萨里大学副校长(1998-2005年) ,现任该大学高级研究所所长。 2017年,他被任命为经济及社会研究理事会成员。<br />
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==工作==<br />
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<big>'''科学知识社会学'''</big><br />
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吉尔伯特和穆尔凯(Gilbert and Mulkay,1984)的突出贡献在于运用[https://en.wikipedia.org/wiki/Discourse_analysis 话语分析]方法到[https://en.wikipedia.org/wiki/Sociology_of_scientific_knowledge 科学知识社会学]中。吉尔伯特和穆尔凯通过对化学领域中一个科学争端的大量定性数据进行话语分析,解释了支撑知识生产的社会过程,尤其是在科学界尚未达成共识的情况下。<br />
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<big>'''大型政府数据集的二次分析'''</big><br />
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他和萨拉·阿尔伯(Sara Arber)一起,率先利用人口普查和调查办公室(Office of Population Censuses and survey)收集的调查数据的计算机文件进行学术分析,而人口普查和调查办公室收集的数据如今在社会学中已成为司空见惯的数据来源。<br />
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<big>'''获取社会保障信息'''</big><br />
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确定英国福利索赔人有权获得哪些福利(如收入支持、税收抵免、残疾生活津贴)的规定非常复杂,而且通常很难让索赔人自行理解。20世纪80年代,随着个人电脑的日益普及,他意识到,为索赔人设计互动程序可能会有所帮助。他开发了一个原型,由当时的卫生社会保障部和公民咨询局采用,是目前咨询中心常规使用的系统的前身。这项工作还有助于理解公共可访问的计算机系统的接口要求、图形接口的使用、以及后来的语音对话接口。<br />
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<big>'''社会模拟'''</big><br />
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奈杰尔·吉尔伯特(Nigel Gilbert)是现代[https://en.wikipedia.org/wiki/Computational_sociology 计算社会学]的创始人之一,这是一门将社会科学研究与[https://en.wikipedia.org/wiki/Social_simulation 模拟技术]相结合的学科,其目标是模拟复杂的政策问题和人类社会的基本方面。他在这一领域的第一项工作是与吉姆•多兰(Jim Doran)合作,模拟法国史前有组织社会的出现。然而这项工作取得的成果并不显著,这促使他在1992年第一次组织了一系列有影响力的“模拟社会”研讨会。随后他建立了:<br />
*[https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=simsoc SIMSOC]邮件列表。2016年5月,该名单有1220名用户。<br />
*《人工社会与社会模拟杂志》(JASSS),创办于1998年,旨在为基于模拟的研究提供出版渠道,吉尔伯特教授在2014年之前一直担任编辑。JASSS期刊在线开放,可以免费获取。<br />
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1997年,CRESS从欧洲委员会的公平项目中获得资金,用于一个名为“图像:改善农业环境政策”的项目,这是一种模拟农民和机构认知特性的方法(1997 - 2000年)。这是他参与的许多社会模拟项目中的第一个,这些项目包括SEIN、FIRMA、SIMWEB、EMIL、NEMO、NEWTIES、PATRES、QLectives、ePolicy、TellMe、GLODERS和P2Pvalue。<br />
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1999年,奈杰尔·吉尔伯特(Nigel Gilbert)和克劳斯·G·特罗伊茨奇(Klaus G. Troitzsch)出版了第一本关于社会模拟的“白皮书”--《社会科学家的模拟》。2008年出版了《基于主体的模型》,现在是基于主体建模的标准参考之一。<br />
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<big>'''其他研究和咨询活动'''</big><br />
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1993年,吉尔伯特创办了《社会学研究在线》杂志,这开创了利用网络作为学术出版媒介的先河。他是萨里大学季刊《社会研究更新》的创始编辑。他和斯图亚特·彼得斯(Stuart Peters)创建了一个期刊管理系统epress,最初是为了让在线社会学研究和JASSS更容易运行,但现在已经商业化,大约有40种期刊使用了这个系统。<br />
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2016年,他担任新成立的关系复杂性评估中心(CECAN)的主任。在关系问题领域,例如生物燃料生产或气候变化——其中食品,能源,水和环境问题相互交织,该中心和环境局、食品标准局,将开创,测试和推广创新的评价方式和方法。<br />
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从2012年到2016年,他是[https://en.wikipedia.org/wiki/DEFRA DEFRA]和[https://en.wikipedia.org/wiki/Department_of_Energy_and_Climate_Change DECC]的社会科学专家小组成员。小组的目的是为两个部门提供高质量,多学科的社会科学建议。在2016年,它被DEFRA 科学顾问委员会的一个子小组社会科学专家组(SSEG)取代,他仍然是该委员会的成员。<br />
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他是欧洲委员会未来和新兴技术计划咨询小组的成员。<br />
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<big>'''奖项和科学认可'''</big><br />
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1999年,他被任命为皇家工程学院院士,以表彰他的工作——“将计算机建模应用于社会科学的先驱”,成为第一位成为该院院士的实践社会科学家。他于2003年被剑桥大学授予理学博士学位。他还是英国计算机学会和皇家艺术学会的会员,以及社会科学研究院的会员(为此,他担任理事会成员)。从2004年到2006年,他担任[https://en.wikipedia.org/wiki/European_Social_Simulation_Associationv 欧洲社会模拟协会](ESSA)的主席。<br />
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吉尔伯特(Gilbert )在2016年生日颁奖典礼上被任命为大英帝国司令(CBE),以提供工程和社会科学服务。<br />
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==社会模拟精选作品==<br />
*奈杰尔·吉尔伯特;吉姆·多兰(Doran)编辑。(1994)。模拟社会:社会现象的计算机模拟。伦敦:UCL出版社。书号 [https://en.wikipedia.org/wiki/Special:BookSources/1-85728-082-2 1-85728-082-2]。<br />
*奈杰尔·吉尔伯特;罗萨里亚·孔戴(1995)。人工社会:社会生活的计算机模拟。泰勒和弗朗西斯。书号 [https://en.wikipedia.org/wiki/Special:BookSources/1-85728-305-8 1-85728-305-8]。<br />
*奈杰尔·吉尔伯特;Troitzsch,Klaus G.(2005)[1999]。对社会科学家的模拟。Milton Keynes:开放大学出版社。书号 [https://en.wikipedia.org/wiki/Special:BookSources/0-335-21600-5 0-335-21600-5]。<br />
*吉尔伯特·奈杰尔(2007)。基于主体的模型。伦敦:Sage出版物。书号 [https://en.wikipedia.org/wiki/Special:BookSources/1-4129-4964-5 1-4129-4964-5]。<br />
*吉尔伯特·奈杰尔(2010)。计算社会科学。伦敦:Sage出版物。书号 [https://en.wikipedia.org/wiki/Special:BookSources/978-1847871718 978-1847871718]。<br />
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==其它作品==<br />
*奈杰尔·吉尔伯特;麦凯(Michael Mulkay)(1984)。打开潘多拉魔盒:科学家话语的社会学分析。剑桥:剑桥大学出版社。书号 [https://en.wikipedia.org/wiki/Special:BookSources/0-521-27430-3 0-521-27430-3]。<br />
*吉尔伯特(Nigel)编辑。(2008)[1992]。研究社会生活。伦敦:Sage出版物。书号 [https://en.wikipedia.org/wiki/Special:BookSources/0-7619-7245-5 0-7619-7245-5]。<br />
*吉尔伯特(Nigel)编辑。(2006)。从研究生到社会科学家:关键技能指南。伦敦:Sage出版物。书号 [https://en.wikipedia.org/wiki/Special:BookSources/0-7619-4460-5 0-7619-4460-5]。<br />
*菲尔丁,简·L;吉尔伯特·奈杰尔(2006)。了解社会统计。贤者出版物。书号 [https://en.wikipedia.org/wiki/Special:BookSources/1-4129-1054-4 1-4129-1054-4]。<br />
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==另外参阅==<br />
*[https://en.wikipedia.org/wiki/Agent-based_model 基于主体的模型]<br />
*[https://en.wikipedia.org/wiki/Artificial_society 人工社会]<br />
*[https://en.wikipedia.org/wiki/Computational_Sociology 计算社会学]<br />
*[https://en.wikipedia.org/wiki/Social_simulation 社会模拟]<br />
*[https://en.wikipedia.org/wiki/Sociology_and_complexity_science 社会学与复杂性科学]<br />
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本词条内容翻译自 wikipedia.org,遵守 CC3.0协议。<br />
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[[Category:计算社会科学]]<br />
[[Category:多主体模型]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%A7%E6%95%B0%E6%8D%AE%E5%AF%B9%E7%A4%BE%E4%BC%9A%E7%A7%91%E5%AD%A6%E4%B8%8E%E8%89%BA%E6%9C%AF%E7%9A%84%E5%BD%B1%E5%93%8D&diff=15184
大数据对社会科学与艺术的影响
2020-10-14T14:16:47Z
<p>Thingamabob:创建页面,内容为“本页面主要内容为计算士2013年9月14日在西五艺术中心的报告 <slidy/> ==什么是大数据?== ===什么样的数据算大数据?=== File:w…”</p>
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<div>本页面主要内容为计算士2013年9月14日在西五艺术中心的报告<br />
<slidy/><br />
==什么是大数据?==<br />
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===什么样的数据算大数据?===<br />
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[[File:wulingfei_130901_1.png|800px]]<br />
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半个多世纪以来,社会科学家其实一直在处理及其小规模的数据,无论是数千上万人的社会调查,还是多次累积的实验,其规模一般都在MB以下。所以,在他们的概念里,超过这个规模的数据就是大数据,更有及其无知者,把数值的大与数据规模的大混为一谈,如此算来,宏观经济研究的GDP也算大数据了。<br />
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在大数据处理的问题上,物理学家和计算科学家远远走在社会科学家前面。欧洲粒子对撞机每天产生42T新数据,哈勃望远镜每天搜集17G新数据,而像谷歌这样的互联网公司每天处理的用户数据在PB级以上。仅仅一个大的互联网社区每天可以就产生几T新数据。(1 P = 103 T = 106 G)总结起来,我们认为,以现有人类的数据处理能力,只有在PB级以上,不得不使用并行计算架构处理的,才叫大数据。<br />
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[[File:Screen Shot 2014-10-18 at 3.37.13 PM.png|800px]]<br />
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我们是否有理由期待,人们很快就可以像了解基本粒子和黑洞一样了解我们自己的社会?<br />
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===这么大的数据如何分析?===<br />
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[[File:Wulingfei 20130901 2.png|800px]]<br />
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并行计算:使用成千上万的机器奴隶进行并行处理。<br />
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现状:根据2008年的数据,Yahoo!拥有1万个机器奴隶。其他互联网公司,如Google, Amazon等,都拥有相似规模的并行计算系统。<br />
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趋势:从批处理计算到流式计算:让机器奴隶们实时响应;从大公司垄断集群的使用到开放云客户端给普通用户。<br />
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==大数据对社会科学的影响:社会科学进入可计算化阶段==<br />
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===物理学的转折===<br />
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没有第谷积累的大量数据,就没有开普勒简洁又美妙的模型<br />
“Kepler … was not satisfied with the complex and still slightly inaccurate result; at certain points the model differed from the data by up to eight arcminutes … ”<br />
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===西方思想回顾===<br />
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两千四百年前(古希腊时代),学科之间只有思考对象的分别,没有研究方法的区别。亚里斯多德使用同样的方法研究行星运动与诗歌,柏拉图把几何定理和城邦政治混为一谈。<br />
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一千一百年前(中世纪),基督教神学(经院哲学)占据统治地位,其他学科几乎完全消亡。经院哲学的意义在于以神学为外壳,保留了部分古希腊思想。<br />
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三百六十年前(启蒙时代),哲学(形而上学)带领所有的其他学科反叛基督教神学。在反叛过程中,哲学获得极高地位,自然科学叫自然哲学,社会科学叫道德哲学,都是哲学的附庸。各个学科之间在研究方法上仍然没有壁垒。达芬奇,笛卡尔,康德,这些人,各有所长,但都有跨界行为。<br />
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启蒙时代时,站在第谷和开普勒肩膀上的牛顿出生。自然科学的黄金时代开始,以物理学为代表的自然科学与其他学科,在研究方法上分道扬镳。但牛顿本人还没有清晰看见这个未来,所以他的书很谦虚地叫《自然哲学的数学原理》。<br />
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两百六十年前,自然科学的积累引发技术的飞跃,工业革命爆发。从此自然科学与技术相互扶持,其他学科望尘莫及。孔德等人非常羡慕,创立“社会物理学”,想要为研究人类社会建立严格的方法论,但并不成功。直到今天,比起物理学等自然科学,社会科学在描述和预测研究对象的规律上,还处在非常落后的状态。<br />
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===为什么孔德的社会物理学没有成功?===<br />
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孔德的思想:1.社会同自然并无本质的不同,没有必要在自然科学和社会科学之间作出划分。2.研究社会要采取实证的办法,即观察法、实验法、比较法和历史法。3 .社会物理学可以分为社会静力学和社会动力学。社会静力学就是从静止的状态去研究社会,是研究一般的社会关系、秩序、结构及其性质的学说。社会动力学是在静力学的基础上研究人类社会发展的动力、速度、方向和规律的学说。<br />
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孔德以后,实证主义尝试一直在被延续,例如从工程数据借力的帕累托式经济分析,从统计学借力的涂尔干式社会调查研究,效仿博物学,对社会结构贴标签分类的马克思韦伯等。<br />
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数据与假设,是一对trade-off。从这个角度看,实证社会科学的问题是:早期没有数据,所以只好依赖假设和对假设的演绎推进认知;后期有了数据,但量非常少,而且关于收集什么样的数据没有达成共识。还是依赖假设和对假设的演绎推进认知。<br />
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===数据采集技术 + 从基础数据中总结的核心定量范式 = 科学===<br />
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[[File:wulingfei_20130901_3.png|800px]]<br />
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回顾科学史,我们发现,所有当代科学都经历了前科学摸索时期。而一个领域与哲学的关系越大,说明越处于前科学阶段,因为数据不够,所以严重依赖假设<br />
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===计算社会科学的崛起===<br />
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David Lazer,Alex Pentland, Albert Barabasi等15个来自社会学、计算机科学、物理学的重要科学家联名在Science(2009-02-06)发表文章Life in the network: the coming age of computational social science一文,宣告计算社会科学诞生。<br />
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Nature (2012-08-22)等杂志发表了Computational social science: making the links等评论,进行推波助澜。<br />
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===计算社会科学的迷思===<br />
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1. 计算社会科学是社会科学的一个快速崛起的子领域<br />
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不对。计算社会科学不是一个子领域,而是社会科学可计算化的过程,是一个新阶段。<br />
就好像实验生物学->分子生物学->信息生物学。现在信息生物学渐渐没落,不是因为不流行,而是<br />
因为太流行了,已经成为共识了,它的历史使命也宣告结束。等到每一个社会科学的学生都掌握<br />
使用互联网搜集分析大数据的技巧,计算社会科学就没落了。<br />
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2.计算社会科学的扩展要很久,起码要等现在社会科学各领域的大学教授们退休,了解互联网技术的<br />
新一代人进入学术资源分配的核心圈才行。<br />
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不用。这是一场来自外部的殖民,而不是来自内部的革命。研究大规模人类行<br />
为,研究社交网络,计算机科学家和物理学家已经做了大量工作,社会科学家正在失去话语权。<br />
社会科学面临这样的情况:要么进行“内部革命”,每一个学生都尽快掌握基于计算机和互联网的<br />
数据采集、分析、可视化等技术,要么被从计算机等领域分裂出来的“human behavior studies”所代替。<br />
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===我们的研究===<br />
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[[File:wulingfei_20130901_4.png|800px]]<br />
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1.研究方向:Kleiber’s law描述了不同物种的能量消耗与体积的普适规律。<br />
West等人在这个基础上建立了生物学的新陈代谢理论。 Bettencourt等将这个理论用于描述人类城市的能量消耗与居民数。<br />
我和jake将这个理论用于描述网站(虚拟世界的生物)的注意力消耗与信息产出之间的关系。<br />
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2.图景:国家,物种和网站,都可以看做一般流系统。货币、能量、注意力在其中流进流出,满足新陈代谢的一般方程。<br />
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3.成果:已在PloS One, Physical Review E, European Physical Journal B等期刊上发表数片论文,得到New Scientist,Science Daily等杂志报道。<br />
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拓展阅读:[http://www.jianshu.com/p/ddc347b0518c 《无形生命》]<br />
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===宇宙的各项同性使得社会物理学是可能的===<br />
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[[File:wulingfei_20130901_5.png|300px]]<br />
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在我看来,宇宙以一种奇妙的方式构成:我们处理的对象每上一个层级,数量和复杂性就迫使我们放弃依靠下一个层级获得的知识来理解本层级的对象。因此,如果我们要相信科学,我们只能坚信科学原理具有这样的特征:每一个层级的对象,只要我们忽略足够多细节,都能看到类似足够简洁的物理法则。我称这种性质为Eadem Mutata Resurgo。<br />
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其实这种观点并不新,它是物理学的平权原理的推演。即把物理宇宙的各项同性(isotropy)加多一个维度:观察的层次(scale)。物理法则不仅invariant of time-space operation,还要invariant of scale operation。<br />
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例如,人们现在各粒子的运动方式相对清晰,化学键也基本明白,到大分子有点搞不定,生命有机体如何形成基本靠猜,到人的行为和社会运动,要从基本粒子开始解释按道理完全就是瞎扯了。但奇怪的是,大规模人类运动的方式又满足基本粒子的levy flight方程了 (Gonzalez et al. , Nature, 2008)。<br />
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对抗复杂性的办法就是忽略信息,但没有大数据,就不知道该忽略什么信息。因为在大规则行为中,次要的信息相互抵消,主要的趋势不断加强,最后涌现出强力的统计法则。 Anderson (1972) 说,More is different。但我要说,他说得还不够透彻。 More is different, but massive is simple。<br />
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===计算社会学课程===<br />
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[http://lingfeiw.gitbooks.io/data-mining-in-social-science/ Data Mining in Social Science]<br />
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==大数据对艺术的影响:数据可视化的兴起==<br />
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===什么是数据可视化?===<br />
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====音乐旋律的可视化====<br />
[[File:wulingfei_20130901_6.png]]<br />
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====游戏玩家活动的可视化====<br />
[[File:wulingfei_20130901_7.png]]<br />
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====Google查询词的可视化====<br />
[[File:wulingfei_20130901_8.png]]<br />
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====Facebook交友关系的可视化====<br />
[[File:wulingfei_20130901_9.png]]<br />
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====互联网网站流量与相对位置的可视化====<br />
[[File:wulingfei_20130901_10.png]]<br />
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====机场航班的可视化====<br />
[[File:wulingfei_20130901_11.png]]<br />
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====科学理论引用关系的可视化====<br />
[[File:wulingfei_20130901_12.png]]<br />
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====用户对在线期刊点击流的可视化====<br />
[[File:wulingfei_20130901_13.png]]<br />
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Eh pá GNR é que não ! Até me causam urac¡Ãirit, o Reininho não tem os requisitos mÃnimos para gravar, até eu canto mais afinado que ele.<br />
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====艺术家的一生的可视化====<br />
[[File:wulingfei_20130901_15.png]]<br />
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===如何完成一个数据可视化项目?===<br />
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====互联网点击流:一个数据可视化项目====<br />
[[File:wulingfei_20130901_16.png|缩略图|none|800px]]<br />
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1. 使用Python从Google Ad Planner上抓取排名前1000的网站列表;利用AlchemyAPI鉴别这些网站使用的语言;从Alexa上抓取这些网站彼此之间的点击流关系 。<br />
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2. 构思,设计网络展示方式及与用户的交互方式。<br />
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3. 使用Python对数据进行预处理。<br />
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4. 使用Processing设计可视化界面。 不同语言网站用不同颜色显示,当用户把鼠标放到相应网站的点上,可以显示网站的流量,语言等基本信息。<br />
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====中国风画板:一个无需数据的可视化项目====<br />
[[File:wulingfei_20130901_17.png|缩略图|none|800px|]]<br />
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其实数字艺术,就是不使用真实数据,而是使用模拟数据的可视化!<br />
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==== 使用NASA卫星照片来分析城市的财富分布:不是用数据画图像,而是反过来,从图像中提取数据 ====<br />
[[File:wulingfei_20130901_18.png|缩略图|none|800px]]<br />
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科学家可以当艺术家,艺术家也可以当科学家!<br />
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===优秀可视化作品分析===<br />
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1. Jer Thorp:一个数据可视化的艺术先锋<br />
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blogDOTblprntDOTcom/<br />
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[[File:wulingfei_20130901_19.png|缩略图|none|800px]]<br />
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2. Jer Thorp作品欣赏一:在New York Times R&D Lab完成的作品Cascade<br />
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[[File:wulingfei_20130901_20.png]]<br />
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3. Jer Thorp作品欣赏二:行星运动<br />
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[[File:wulingfei_20130901_21.png]]<br />
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==一些学习材料==<br />
[[File:wulingfei_20130901_22.png|缩略图]]<br />
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* http://www.visualcomplexity.com/vc/<br />
* http://datavlab.org/<br />
* http://www.flowjustflow.com/<br />
* http://tinyurl.com/dj4epq<br />
* http://blog.counter-strike.net/science/<br />
* http://data-arts.appspot.com/globe-search<br />
* http://www.openprocessing.org/<br />
* http://www.vizinsight.com/<br />
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现状:纽约时报等建立了专门的可视化实验室,将传统新闻行业的重心转移到interactive data visualization上来。哥伦比亚大学也已经建立Digital journalism研究中心。<br />
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趋势:艺术家、工程师、新闻记者身份将日趋模糊。界面设计,写代码操控数据,故事提取展现能力缺一不可。<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E7%B3%BB%E7%BB%9F%E7%A0%94%E7%A9%B6%E6%89%80&diff=15178
复杂系统研究所
2020-10-14T14:14:58Z
<p>Thingamabob:创建页面,内容为“== 研究所简介 == 复杂系统研究所(Institute For the Study of Complex System,ISCS),总部在美国华盛顿州的西雅图。 这是一个专门…”</p>
<hr />
<div>== 研究所简介 ==<br />
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复杂系统研究所(Institute For the Study of Complex System,ISCS),总部在美国华盛顿州的西雅图。<br />
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这是一个专门研究复杂性的进化/功能方法和社会正义的新生物学方法的研究组织。<br />
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研究所的其他工作包括研究热力学和生物学之间关系的新方法,称为“热经济学”,一种新的信息理论的控制论方法,称为“控制信息”,以及研究生物学方法—一套基本需要的社会指标,作为传统的收入或“福祉”或“幸福”的替代方法。<br />
<br />
== 关于Peter A. Corning ==<br />
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[[File:PeterCroning.jpg|350px|居中]]<br />
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研究所主任Peter A. Corning,博士,出生于加利福尼亚州的帕萨迪纳市。他在布朗大学获得本科学历,之后在新闻周刊杂志担任海军飞行员和科学作家两年,之后回到纽约大学研究生院完成跨学科社会科学 - 生命科学博士学位。随后,他在科罗拉多大学的行为遗传学研究所获得了NIMH博士后研究和研究奖学金,随后他在斯坦福大学的人类生物学课程中任教九年,同时还受聘于斯坦福大学行为遗传学实验室和工程经济系统部。<br />
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过去的二十年里,康宁博士不仅担任了非营利性机构复杂系统研究所的主任,同时也是加利福尼亚州帕洛阿尔托一家私人咨询公司的创始合伙人。多年来,他发表了大量的研究论文,以及七本专著——其中一本是关于协同作用在进化中的作用的理论专著,书名为:《协同作用假设:进步演化理论(McGraw-Hill,1983)》。他最近的几著作包括“[http://complexsystems.org/publications/the-fair-society/ The fair society: the science of human nature and the pursuit of social justice(《公平社会:人性的科学和社会正义的追求》)]”(芝加哥大学出版社2011),以及《协同选择:合作如何塑造进化和人类的崛起》(World Scientific 2018)。<br />
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[[File:Fsoc.png|450px|居中]]<br />
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除此之外,康宁博士还是多个专业科学组织的成员,并在美国和欧洲的学术机构进行了广泛的演讲。目前,他是Evolution Institute科学顾问委员会的成员、是国际系统科学学会的前任主席以及国际生物经济学会的财务主管以及政治和生命科学协会的董事会成员。同时他还是进化史诗史上的董事会成员,是国际人类行为学会、人类行为与进化学会、国际内吞细胞生物学会、欧洲社会生物学会和国际协会的积极贡献成员。<br />
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1996年,他还在匈牙利布达佩斯学院(国际高级研究所)获得进化生物学研究奖学金。<br />
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== 研究内容 ==<br />
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===复杂性的出现===<br />
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* [http://complexsystems.org/publications/synergistic-selection-a-darwinian-frame-for-the-evolution-of-complexity/ "Synergistic Selection" : A Darwinian frame for the evolution of complexity(“协同选择”:复杂性延边的达尔文框架)]:“协同作用假设”和密切相关的“协同选择”概念涉及理论框架的转变。该理论认为,各种合作功能效应(协同效应)随着时间的推移提供了选择性优势,并推动了复杂性的演变;该理论关注各种形式合作的利益和成本。<br />
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* [http://complexsystems.org/publications/complexity-is-just-a-word/ Complexity is just a word复杂性只是一个文字]:什么是复杂性?作家记者乔治约翰逊在最近的“科学时报”以及“纽约时报”(1997年5月5日)的科学板块写在标题这样写道:“复杂性的研究者应当思考它的全部内容”。然而约翰逊报告称,现在科学家们仍然没有达成一致意见的定义。<br />
<br />
* [http://complexsystems.org/publications/synergy-and-the-systems-sciences/ Synergy and the Systems Sciences (SYNERGY与系统科学)]:虽然它的作用往往不受重视,但协同作用可被视为系统科学的核心概念之一。实际上,协同作用在自然界和人类社会中都是普遍存在的现象。在这里,作者简要讨论了两者之间关系的某一个方面。<br />
<br />
* [http://complexsystems.org/publications/book-review-from-complexity-to-life/ Review of "From Complexity ro Life"(回顾“从复杂到生活”)]:最后,编辑Niels Gregersen的最后一章是如何挽救本书试图推进的“案例”。通过默认对进化生物学的更加复杂和平衡的理解,格雷格森巧妙地超越了否则可能破坏组织者基本目标的缺点和误解(甚至一些内部矛盾)。<br />
<br />
* [http://complexsystems.org/publications/rotating-the-necker-cube-a-bioeconomic-approach-to-cooperation-and-the-causal-role-of-synergy-in-evolution/ Rotating the necker cube:a bioeconomic approach to cooperation and the causal role of synergy in evolution(旋转尼克立方体:合作的生物经济学方法和协同作用在进化中的因果作用)]:在这里,作者简要探讨了进化理论范式转换的案例,重点关注经济学和功能协同作用作为一类独特的因果影响的作用。<br />
<br />
* [http://complexsystems.org/publications/emergence-theory-or-natural-selection/ Emergence theory or natural selection(《回顾“生物出现”》)]:罗伯特里德的挑衅书是不正常的——他用一种语义的手法来宣称非达尔文的新兴进化论,然而事实却不应该是这样的。<br />
<br />
* [http://complexsystems.org/publications/the-re-emergence-of-emergence-a-venerable-concept-in-search-of-a-theory/ The re-emergence of emergence a venerable concept in search of a heory(《“崛起”的再现:一个寻求理论的尊严概念》)]:“出现”是一个具有悠久历史和进化论理论模糊的概念。本文简要介绍了该术语的历史,并详细介绍了其当前的一些用法。解释复杂性的简化方法需要寻找潜在的“出现法则”。另一种选择是“协同假设”,它侧重于“经济学” - 新兴整体产生的功能效应及其选择性后果。<br />
<br />
* [http://complexsystems.org/publications/what-is-life-among-other-things-its-a-synergistic-effect/ What is life among other things its a synergistic effect(《生活是什么?在其他事务中,这是一种协同效应》)]:近年来,有许多不同的方式来描述和描述生活现象。作者认为,协同作用也应该是这诸多方式中的一员。<br />
<br />
===演化===<br />
<br />
====[http://complexsystems.org/publications/synergistic-selection-how-cooperation-has-shaped-evolution-and-the-rise-of-humankind/ Synergistic selection(协同选择)]====<br />
<br />
* [http://complexsystems.org/publications/294-2/ The evolution of politics: a biological approach(《政治的演变:一种生物学方法》)]:我们必须从如何界定政治的问题开始。但不幸的是,即使对这一重要的社会现象关于它究竟应该如何定性现在尚无定论,更遑论如何解释它,迄今为止科学家们尚未达成共识。<br />
<br />
* [http://complexsystems.org/publications/toward-an-ecological-way-of-death/ Toward an ecological way of death《走向生态死亡的方式》]:如果我们要认真回收再利用,并减少我们对自然资源的消耗,为什么不回收自己呢?<br />
<br />
其他相关文章内容[http://complexsystems.org/topic/evolution/ 详情]<br />
<br />
===信息论===<br />
<br />
* [http://complexsystems.org/publications/missing-link-in-the-science-of-cybernetics/ Missing link in the science of cybernetics(《控制信息论:控制科学中的“缺失环节”)》]:虽然克劳德·香农的信息统计方法已经做出了许多有价值的贡献,但它对信息的功能属性视而不见。在这里,我们提出了一种新的控制论信息,我们称之为“控制信息”。它被定义为控制“有目的”(控制论)过程中物质/能量的获取,处置和利用的能力(知识)。我们还提出了在给定环境中可由给定信息单元控制的可用能量数量的形式化。<br />
<br />
* [http://complexsystems.org/publications/the-evolution-of-politics/ The evolution of politics(《协同作用,控制论和政治的演变》)]:从生物科学中不断增长的理论和研究文献的角度来看,随着时间的推移,复杂生命系统的“进步”演变,以及控制论(通信和控制过程)的科学,人类社会中的政治现象代表了一种变异,主要阐述了关于进化主题的。在生物组织的所有“层面”,包括人类的进化,政治进程在面向目标的合作系统中发挥了不可或缺的作用。<br />
<br />
===社会公正===<br />
<br />
* [http://complexsystems.org/publications/the-fair-society-and-challenges-to-democracy/ The fair society and challenges to democracy(《公平社会与民族挑战》)]:挪威正在藐视长期利益。挪威及其斯堪的纳维亚表兄弟是历史上的例外,而非规则。事实上,很少有社会能够实现公平正义,更不用说维持一个真正公平的社会契约。<br />
<br />
* [http://complexsystems.org/publications/the-fair-society-a-new-model-for-social-justice-in-the-21st-century/ The fair society a new model for social justice in the 21st century(《公平社会;21世纪社会公正的新模式》)]:世界各地经济不平等,气候变化,贫困,内乱和暴力政治冲突的多重挑战需要对社会正义的新思考。<br />
<br />
* [http://complexsystems.org/publications/the-fair-society-its-time-to-re-write-the-social-contract/ The fair society its time to re-write the social contract(《公平社会:现在是重构社会契约的时候了》)]:隐含的“社会契约”将任何合理稳定和谐的社会联系在一起,在这个国家正在受到腐蚀,带来负面的潜在后果,现在是时候重新定义公平,重新编写社会契约,以公平为先。在这里,作者提供了一个新的、基于生物学的范式的概要,并将概述一些对公共政策的影响。<br />
<br />
其他相关文章内容[http://complexsystems.org/topic/social-justice/ 详情]<br />
<br />
===协同选择===<br />
<br />
* [http://complexsystems.org/publications/synergistic-selection-a-darwinian-frame-for-the-evolution-of-complexity/ Synergistic selection a darwinian frame for the evolution of complexity(《“协同选择”:复杂性延边的达尔文框架》)]:“协同作用假设”和密切相关的“协同选择”概念涉及理论框架的转变。该理论认为,各种合作功能效应(协同效应)随着时间的推移提供了选择性优势,并推动了复杂性的演变。该理论关注各种形式合作的利益和成本。<br />
<br />
其他相关内容[http://complexsystems.org/topic/synergistic_selection/ 详情]<br />
<br />
===协同作用===<br />
<br />
* [http://complexsystems.org/publications/294-2/ The evolution of politics: a biological approach(《政治的演变:一种生物学方法》)]:我们必须从如何界定政治的问题开始,但不幸的是,即使对这一重要的社会现象它究竟应该如何定性都尚无定论,更遑论如何解释它,在这一点上科学家们从来没有得出准确结论。<br />
<br />
* [http://complexsystems.org/publications/the-lessons-of-the-titanic-and-iraq-revisited/ The lessons of the titanic and iraq revisited(《重新审视泰坦尼克号的教训》)]:从导致这一历史性灾难的众多“假设”的角度解析并获得从中许多教训。<br />
<br />
* [http://complexsystems.org/publications/synergy-another-idea-whose-time-has-come/ Synergy another idea whose time has come(《协同作用:时间盗来的另一个想法》)]:我们的日常生活受潮汐影响......今年的潮流往往可能是明年的滞销项目。虽然我们认为科学不受这种“无关”的影响,但显然事实并不是这样的。托马斯库恩在他着名的《科学革命结构》(1972)一书中指出,科学受到与不同“范式”相关的潮汐效应的影响很大。<br />
<br />
其他相关内容[http://complexsystems.org/topic/synergy/ 详情]<br />
<br />
===热力学===<br />
<br />
* [http://complexsystems.org/publications/an-aid-to-navigation-through-an-intellectual-fog-bank/ An aid to navigation through an intellectual fog bank(《多学科思维概念基础》)]:这本朴实无华的书写得十分简单明亮,包含了一个直截了当的描述性标题,由斯坦福大学出版社出版但并没有大张旗鼓要求每个大学生和他们的教授阅读。<br />
<br />
* [http://complexsystems.org/publications/thermoeconomics-beyond-the-second-law/ Thermoeconomics beyond the second law(热经济学:超越第二定律)]:物理学家Erwin Schrodinger的《生命是什么?》(1945)激发了许多后来的努力来解释生物进化,特别是复杂系统的演化,根据热力学第二定律和“熵”和“负熵”的概念。然而,与这种范式相关的问题是多方面的。其中一些问题将在本文的第一部分中着重讲解,并且将对其中的一些理论进行简要的评价。<br />
<br />
其他相关内容参见[http://complexsystems.org/topic/thermodynamics/ 网站]<br />
<br />
== 相关文章及书籍 ==<br />
<br />
* 《How to Feed the World in the Age of Climate Change》 (2019) PR for People® The Connector Magazine, May, 4-9. <br />
<br />
* 《Teleonomy and the Proximate-Ultimate Distinction Revisited》 (2019), © Biological Journal of the Linnean Society 127(4): 912–916.<br />
<br />
* 《The Evolution of Politics: A Biological Approach 》(2017). In Handbook of Biology and Politics,Steven A. Peterson and Albert Somit eds., pp. 55-84. London: Edward Elgar.<br />
<br />
* 《The Science of Human Nature and the Social Contract: A Biological Frame for Public Policy》 ( 2017). In Handbook of Biology and Politics,Steven A. Peterson and Albert Somit eds., pp. 406-430. London: Edward Elgar.<br />
<br />
* 《Systems Theory and the Role of Synergy in the Evolution of Living Systems》 (2013).Systems Research and Behavioral Science, DOI: 10.1002/sres2191.<br />
<br />
* 《Synergy and the Evolution of ‘Superorganisms’: Past, Present and Future》(in Russian), (2004). In Challenge to Cognition: Strategies of Science Development in the Modern World, Narine Udumyan ed., pp. 184-221. Moscow: Nauka.<br />
<br />
== 博客 ==<br />
<br />
在研究所的官网上还提供了了许多彼得的博客,现将部分最新信息罗列如下:<br />
<br />
* [https://complexsystems.org/576/shareholder-capitalism-vs-stakeholder-capitalism/ SHAREHOLDER CAPITALISM VS. STAKEHOLDER CAPITALISM 股东资本主义 VS 利益相关者资本主义](2019年9月17日)<br />
<br />
* [https://complexsystems.org/568/platos-dilemma-it-haunts-us-still/ PLATO’S DILEMMA: IT HAUNTS US STILL 柏拉图的困境: 它仍然困扰着我们](2019年9月6日)<br />
<br />
* [https://complexsystems.org/544/the-climate-refugee-crisis/ THE CLIMATE REFUGEE CRISIS 气候难民危机](2019年8月22日)<br />
<br />
* [https://complexsystems.org/536/sustainable-development-hows-it-going/ “SUSTAINABLE DEVELOPMENT”: HOW’S IT GOING? “可持续发展” : 进展如何?](2019年8月13日)<br />
<br />
==最新研究==<br />
<br />
关于超级有机体——我国濒危物种的“新社会契约”<br />
<br />
===关键词===<br />
<br />
窥探未来 | “未来不是以前的样子” | 历史的教训:过去,现在和未来 | “团结还是灭亡” | 建立超级有机体 | 进化的下一个重大转变<br />
<br />
===书籍说明===<br />
<br />
在这本书中,彼得·科宁认为,现在我们面临着一个重大的、不可避免的集体选择问题——就像我们漫长的进化史一样,这将决定我们人类作为一个物种的最终命运。康宁博士的案例以科学和知情的想象为基础,引入生动的场景和新颖的变革理念。使读者可以快速地带入到情景当中,并且可以清楚地看到未来的替代方案。我们究竟是应该代表“共同利益”合作行事,还是追求“我们与他们对比”,以适者生存方式为生?在简要说明为什么我们现在处于作为一个物种的临界点的情况之后,康宁博士构建了一个新的愿景,其中包括我们的社会价值观、经济系统的变革性变化以及我们实现全球“超级有机体”的政治理想——这是生物学家经常用来描述一个综合的,有社会组织的物种的概念。其中一个非常关键的想法是所谓构造新的“社会契约”,它旨在创造一个合法和公平的全球社会。除此之外,它还将包括“普遍的基本需求保证。”康宁博士的处方基于生物学和人性的新兴科学,并且是独一无二的。这些核心公平原则的实际后果将导致各级的重大政治变革,首先是联合国全面的“全球政府倡议”,重大的机构升级和强大的权力,以及建立两个强大的新超级机构——全球基础设施基金和全球应急管理局等。然而,每个国家和每个社区也必须有积极的变化。“公众信任”这一对政府的古老愿望现在已成为人类生存的必要条件。<br />
<br />
相关内容及最新研究发现将在[http://complexsystems.org/podcasts/ 博客网页]中发布<br />
<br />
== 联系方式 ==<br />
<br />
1、研究所邮箱:info@complexsystems.org<br />
<br />
2、Peter Corning博士邮箱:pacorning@complexsystems.org<br />
<br />
== 相关链接 ==<br />
<br />
[https://complexsystems.org/ 研究所官网]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E7%B3%BB%E7%BB%9F%E5%85%A5%E9%97%A8%E5%9B%BE%E4%B9%A6&diff=15179
复杂系统入门图书
2020-10-14T14:14:24Z
<p>Thingamabob:创建页面,内容为“ 该书单收集的原则是:1、内容简单、可读性强;2、对复杂系统各个学派介绍得比较全面 ==复杂性思维:物质、精神和人类…”</p>
<hr />
<div><br />
<br />
该书单收集的原则是:1、内容简单、可读性强;2、对复杂系统各个学派介绍得比较全面<br />
<br />
==复杂性思维:物质、精神和人类的计算动力学==<br />
<br />
[[File:s27302712.png|300px]]<br />
<br />
* 作者: [德]克劳斯·迈因策尔 (Klaus Mainzer) <br />
*出版社: 上海辞书出版社<br />
*原作名: Thinking in Complexity<br />
*译者: 曾国屏 / 苏俊斌 <br />
*出版年: 2014-4-1<br />
*页数: 584<br />
*定价: 85.00<br />
*装帧: 平装<br />
*丛书: 辞海译丛<br />
*ISBN: 9787532638925<br />
<br />
===内容简介===<br />
<br />
复杂性科学是可与相对论、量子力学媲美的20世纪重大科学突破之一。在某种意义上,复杂性对整个科学体系的影响,也许比后两者更深刻、更广泛。进入21世纪,探索和理解复杂性,依然受到自然、社会、人文等各学科的共同关注。德国著名哲学家、复杂性科学专家克劳斯o迈因策尔教授的这本名著已出至第五版,它从哲学的高度,广泛涉猎物理学、生命科学、认知科学、计算机科学、经济学、社会学等诸多方面,揭示了不同学科体现出的共同的复杂性特征,以详尽而不失之繁琐的例证,和严谨而又尽可能通俗的笔法,阐释了对复杂性的探索将如何引起人们思维方式的深刻变化。<br />
<br />
===作者简介===<br />
<br />
克劳斯·迈因策尔 (Klaus Mainzer) 德国科学哲学家。现为慕尼黑工业大学教授。在复杂系统、非线性动力学等领域多有建树,除本书外,还著有《大自然的对称性》、《对称与复杂:非线性科学的魂与美》等。<br />
主译:曾国屏 清华大学人文学院科学技术与社会研究所教授,清华大学深圳研究生院社会科学与管理学部主任。长期从事科学•技术•产业与社会问题、科技传播普及、自然辩证法和复杂性科学哲学问题的研究,有著译十余种。<br />
<br />
===目录===<br />
<br />
中文第2版序<br />
<br />
第5版序<br />
<br />
第4版序<br />
<br />
第3版序<br />
<br />
第2版序<br />
<br />
第1版序<br />
<br />
第1章导言:从线性思维到非线性思维<br />
<br />
第2章复杂系统和物质进化<br />
<br />
2.1 亚里士多德的宇宙和赫拉克利特的逻各斯<br />
<br />
2.2牛顿宇宙、爱因斯坦宇宙和拉普拉斯妖<br />
<br />
2.3哈密顿系统、天上的混沌和量子世界的混沌<br />
<br />
2.4保守系统、耗散系统和有序涌现<br />
<br />
2.5纳米世界和自建构材料的复杂系统<br />
<br />
2.6时间序列分析、分形、多重分形<br />
<br />
第3章复杂系统和生命进化<br />
<br />
3.1从泰勒斯到达尔文<br />
<br />
3.2玻耳兹曼的热力学和生命进化<br />
<br />
3.3复杂系统和有机物进化<br />
<br />
3.4复杂系统和种群生态学<br />
<br />
3.5复杂系统和生命的幂律<br />
<br />
第4章复杂系统和心一脑进化<br />
<br />
4.1从柏拉图的灵魂到拉美特利的“人是机器”<br />
<br />
4.2复杂系统和神经网络<br />
<br />
4.3大脑和意识形成<br />
<br />
4.4意向性和脑爬虫体<br />
<br />
4.5复杂性和具身心智<br />
<br />
第5章 复杂系统和可计算性的进化<br />
<br />
5.1莱布尼茨和普遍数学<br />
<br />
5.2可计算性和算法复杂度<br />
<br />
5.3信息、概率和l/f复杂性<br />
<br />
5.4随机过程、概率吸引子和概率复杂性<br />
<br />
5.5 量子信息、量子计算机和量子复杂性<br />
<br />
5.6元胞自动机、混沌和随机性<br />
<br />
第6章 复杂系统和人工生命、人工智能的演化<br />
<br />
6.1图灵和符号人工智能<br />
<br />
6.2神经网络和协同计算机<br />
<br />
6.3细胞神经网络和模拟神经计算机<br />
<br />
6.4通用细胞神经网络和动力复杂性<br />
<br />
6.5有机计算、神经仿生学和具身机器人<br />
<br />
6.6具身人工智能和人工生命<br />
<br />
第7章复杂系统和经济演化<br />
<br />
7.1亚当·斯密的经济学和市场均衡<br />
<br />
7.2复杂经济系统、混沌和随机性<br />
<br />
7.3 巴舍利耶的金融理论和市场均衡<br />
<br />
7.4复杂金融市场、湍流和幂律<br />
<br />
7.5经济物理学的展望<br />
<br />
第8章 复杂系统和人类文化、社会的进化<br />
<br />
8.1从亚里士多德的城邦到霍布斯的利维坦<br />
<br />
8.2复杂的社会系统和文化系统<br />
<br />
8.3复杂通信网络、信息检索和个性化信息系统<br />
<br />
8.4复杂移动网络、泛在计算和适应性在线学习<br />
<br />
第9章关于未来、科学和伦理学的结语<br />
<br />
9.1复杂性、预测和未来<br />
<br />
9.2复杂性、科学和技术<br />
<br />
9.3复杂性、责任和自由<br />
<br />
参考文献<br />
<br />
人名译名对照<br />
<br />
中文第1版译后记<br />
<br />
中文第2版译后记<br />
<br />
==系统科学==<br />
<br />
<br />
[[File:s5657421.jpg|300px]]<br />
<br />
*作者: 许国志 编 <br />
*出版社: 上海科技教育出版社<br />
*出版年: 2000-1<br />
*页数: 413<br />
*定价: 39.60元<br />
*装帧: 简裝本<br />
*ISBN: 9787542823557<br />
<br />
===内容简介===<br />
<br />
《系统科学》是在总结我国二十多年来开展系统科学和系统工程研究、应用、教学的基础上编写的,并在全国范围广泛征求意见,反映了同行的共识性认识。《系统科学》全面介绍了系统科学的基础理论、应用理论和工程应用,重点是基础理论的内容。《系统科学》系统阐述了对各类系统的结构、功能和演化有普适意义的动力学系统理论(包括分岔、混沌等)、自组织理论、随机性理论,以及简单巨系统、复杂适应系统、开放的复杂巨系统的理论,对信息论、控制论、运筹学、系统工程方法论等系统工程技术作了简要介绍。<br />
<br />
<br />
===目录===<br />
<br />
前言<br />
<br />
第1章 绪论<br />
<br />
1.1 古今系统思想概述<br />
<br />
1.2 系统科学的形成和发展<br />
<br />
1.3 系统科学的体系结构和重要地位<br />
<br />
第2章 基本概念与方法<br />
<br />
2.1 系统、结构、层次<br />
<br />
2.2 环境、行为、功能<br />
<br />
2.3 状态、演化、过程<br />
<br />
2.4 系统方法论<br />
<br />
2.5 模型方法<br />
<br />
第3章 连续动态系统<br />
<br />
3.1 连续动态系统的数学描述<br />
<br />
3.2 轨道、暂态、定态<br />
<br />
3.3 稳定性<br />
<br />
3.4 吸引子与目的性<br />
<br />
3.5 周期运动与回归性<br />
<br />
3.6 分岔<br />
<br />
3.7 突变<br />
<br />
3.8 过渡过程特性<br />
<br />
第4章 离散动态系统<br />
<br />
4.1 离散映射与离散动力学<br />
<br />
4.2 离散混沌<br />
<br />
4.3 几种自动器网络模型<br />
<br />
4.4 遗传算法<br />
<br />
第5章 系统的随机性<br />
<br />
5.1 随机过程与随机涨落<br />
<br />
5.2 主方程和福克尔-普朗克方程<br />
<br />
5.3 随机网络模型<br />
<br />
第6章 系统的自组织<br />
<br />
6.1 自组织与他组织<br />
<br />
6.2 两种有序原理<br />
<br />
6.3 自组织理论<br />
<br />
6.4 自组织的几种形式<br />
<br />
第7章 简单巨系统<br />
<br />
第8章 复杂适应系统理论及其应用<br />
<br />
第9章 开放的复杂巨系统<br />
<br />
第10章 技术科学层次的系统科学<br />
<br />
第11章 系统科学的工程技术<br />
<br />
结语<br />
<br />
注释与参考文献<br />
后记<br />
<br />
索引<br />
<br />
<br />
<br />
==Complexity==<br />
<br />
[[File:s4241945个.png|300px]]<br />
<br />
*作者: Mitchell M. Waldrop <br />
*出版社: Simon & Schuster<br />
*副标题: The Emerging Science at the Edge of Order and Chaos<br />
*出版年: 1992-1-15<br />
*页数: 384<br />
*定价: USD 15.00<br />
*装帧: Paperback<br />
*ISBN: 9780671872342<br />
<br />
<br />
===内容简介===<br />
<br />
In a rented convent in Santa Fe, a revolution has been brewing. The activists are not anarchists, but rather Nobel Laureates in physics and economics such as Murray Gell-Mann and Kenneth Arrow, and pony-tailed graduate students, mathematicians, and computer scientists down from Los Alamos. They've formed an iconoclastic think tank called the Santa Fe Institute, and their radical idea is to create a new science called complexity. These mavericks from academe share a deep impatience with the kind of linear, reductionist thinking that has dominated science since the time of Newton. Instead, they are gathering novel ideas about interconnectedness, coevolution, chaos, structure, and order - and they're forging them into an entirely new, unified way of thinking about nature, human social behavior, life, and the universe itself. They want to know how a primordial soup of simple molecules managed to turn itself into the first living cell - and what the origin of life some four billion years ago can tell us about the process of technological innovation today. They want to know why ancient ecosystems often remained stable for millions of years, only to vanish in a geological instant - and what such events have to do with the sudden collapse of Soviet communism in the late 1980s. They want to know why the economy can behave in unpredictable ways that economists can't explain - and how the random process of Darwinian natural selection managed to produce such wonderfully intricate structures as the eye and the kidney. Above all, they want to know how the universe manages to bring forth complex structures such as galaxies, stars, planets, bacteria, plants, animals, and brains. There are commonthreads in all of these queries, and these Santa Fe scientists seek to understand them. Complexity is their story: the messy, funny, human story of how science really happens. Here is the tale of Brian Arthur, the Belfast-born economist who stubbornly pushed his theories of economic ch<br />
<br />
<br />
<br />
===《复杂》导读===<br />
<br />
<br />
作者:张江<br />
<br />
<br />
《复杂》这本书的出版可以说给中国的学术界打开了一扇窗子,让我们真正的了解了国外的复杂性科学。有人称《复杂》这本书是复杂性科学的“圣经”我看也一点不为过。《复杂》类似于纪实小说,读起来轻松愉快。然而这也许会让不熟悉的人摸不到头脑,因为单单从每一章的标题根本读不出来这一章所要讲述的主要内容。事实上,《复杂》叙述的学术内容涵盖了经济、生命、计算机、物理、哲学等等多门学科、多个层面。我在此做一个总结,方便大家阅读,并希望你能在相应的章节找到自己最想要的东西。<br />
<br />
1、爱尔兰的英雄<br />
<br />
主要叙述阿瑟(Brian Arthur)的故事,包括他的报酬递增率,以及新经济学上的一些洞见,还有对新古典经济学关于最优化经济人的质疑。当然文中也介绍了他的一些个人经历和科研成果。从这章你会体会到一场革命即将来临,这是一个非常好的复杂科学的切入点。如果你感兴趣的领域是经济学,并同样感受到新古典经济学的不足之处,那么这章一定要看。<br />
<br />
2、老师倒戈<br />
<br />
主要叙述考温、盖尔曼这些权威的物理学家、诺贝尔奖获得者是如何萌发研究跨学科的想法并筹建圣塔菲研究所的。其中包括了这些专家对自己以前研究方法的质疑,他们称新兴的方法为复杂系统方法。文中还介绍了一些物理学的知识。如果你对物理学感兴趣,建议看这章。<br />
<br />
3、造物主的秘密<br />
<br />
主要叙述考夫曼的个人研究经历,以及他的关于基因网络(外文大概叫boolean network)方面的研究,这个网络有望解释一个受精卵是如何演化出生物个体的。另外,这里也包括了对生命起源这个问题的研究。就是用计算机模拟地球在产生生命的时候的化学环境,看看是否会产生出原始的生命体。如果你对生物学着迷,就一定要看这章。<br />
<br />
4、“你们真的相信这套?”<br />
<br />
这一章内容很少,主要讲圣塔菲研究所的一场很重要的经济学研讨会,会议邀请了经济学家和物理学家,描述了用物理学的视角看待经济科学中问题的方法,以及双方的争论。<br />
<br />
5、游戏高手<br />
<br />
主要讲述约翰 荷兰德(John Hollad)的个人研究经历和他的科研成果。主要包括遗传算法、分类器系统(这个分类器系统是一个能够自己进行学习的专家系统,搞专家系统的同志们一定要了解这个)。正如文中所说,hollad对复杂适应系统的理解和洞察在当时可以说超越了圣塔菲研究所的其他人。他提出了,人们要研究复杂系统更要研究复杂的适应系统。他在很多年前就提出了很多非同寻常的观点,包括对人工智能的认识。如果你是搞计算机或者自动化相关领域的,就不能不了解John Holland的思想。<br />
<br />
6、混沌边缘的生命<br />
<br />
讲述郎顿(lanton)和他的人工生命这门新兴学科的故事。如果说第4章以前的叙述仅仅是人们认识到了复杂系统这个东西,那么从这一章开始,人们开始意识到研究复杂系统的重要手段方法就是计算机模拟。这一章就是用计算机研究生命的思考。其中朗顿的混沌边缘的生命的概念不可谓不深刻,它指出了生命、复杂等现象是由何而来的。如果你是编程高手、计算机专家、生命科学专家就要看看这一章。<br />
<br />
7、玻璃房中的农民经济<br />
<br />
如果说第一章是提出经济系统中的复杂性这个问题,那么这一章叙述的就是如何解决问题。答案就在于计算机模拟。文中叙述了arthur,holland等人是如何用复杂系统、计算机仿真的观点研究经济的,他们提出了一个ASM(人工股市模拟)的系统构思,这个ASM可以在网上找到,可以说是第一个模拟经济的复杂系统模型。另外,里面还介绍了合作与竞争的问题,包括axlord的囚徒困境博弈的计算机程序竞赛等有意思的东西。如果你是经济学、管理科学、社会科学的爱好者,那么建议一定看看这一章的东西。<br />
<br />
8、等待卡诺特<br />
<br />
作者通过比较热力学的发展和复杂科学的发展指出,现在的复杂系统缺乏一个统一的理论就象是热力学第二定律一样能够非常抽象的刻画出复杂适应系统的一般描述和解决问题的通用途径。可以说这一章是前面各章的一个升华,人们从单个复杂适应系统中总结出了好多通用的规律,而这一章是讲如何把这些发现连成一片。文中简单叙述了圣塔菲中的高手们是如何探讨这个问题的,并提到一般的复杂适应系统理论呼之欲出。可以说这章介绍了复杂系统科学在当时的研究现状和进展。理论家们不要错过这一章。<br />
<br />
9、乘胜前进<br />
<br />
这一章又是整本书的一个升华,可以说这一章是复杂系统科学的一个展望。作者重新强调了复杂性科学的基本含义和独立的视角。阿瑟提到了复杂系统观点是一种综合的方法,并且讨论了东方古老思想与复杂系统的关系。<br />
<br />
==生命是什么==<br />
<br />
[[File:s1670257个.png|300px]]<br />
<br />
* 作者: [奥]埃尔温·薛定谔 <br />
*出版社: 湖南科学技术出版社<br />
*译者: 罗来欧 / 罗辽复 <br />
*出版年: 2005-3-1<br />
*页数: 190<br />
*定价: 19.00元<br />
*装帧: 平装<br />
*丛书: 第一推动丛书<br />
*ISBN: 9787535737229<br />
<br />
===内容简介===<br />
<br />
科学,特别是自然科学,最重要的目标之一,就是追寻科学本身的原动力,或曰追寻其第一推动。同时,科学的这种追求精神本身,又成为社会发展和人类进步的一种最基本的推动。<br />
科学总是寻求发现和了解客观世界的新现象,研究和掌握新规律,总是在不懈地追求真理。科学是认真的、严谨的、实事求是的,同时,科学又是创造的。科学的最基本态度之一就是疑问,科学的最基本精神之一就是批判。<br />
诺贝尔奖获得者埃尔温·薛定谔的《生命是什么》是20世纪的伟大科学经典之一它是为门外汉写的通俗作品,然而事实证明它已成为分子生物诞生和随后DNA发现的激励者和推动者,本书把《生命是什么?》和《意识和物质》合为一卷出版,后者也是他写的散文,文中研究了那些自古以来就使哲学家困惑迷离的问题,和这两篇经典著作放在一块的是薛定谔的自传。通过对他一生的回顾和引人入胜的描述,提供了他从事科学著作的背景材料。<br />
<br />
===作者简介===<br />
<br />
埃尔温·薛定谔(1887-1961),奥地利物理学家。20世纪的前30年中物理学经历了一次大革命,解决了微观运动的基本规律问题。薛定谔生活在这个时代,1926年他提出了波动力学,是量子力学的标准形式之一。薛定谔因此而获得诺贝尔奖。后来他的兴趣转向生命科学,1943年写的《生命是什么》,为分子生物学的诞生作了概念上的准备。<br />
<br />
===目录===<br />
<br />
第一部分 生命是什么.<br />
<br />
前言<br />
<br />
序言<br />
<br />
第一章 经典物理学家走近这个主题<br />
<br />
1 研究的一般性质和目的<br />
<br />
2 统计物理学 结构上的根本差别<br />
<br />
3 一个朴素物理学家对这个主题的探讨<br />
<br />
4 为什么原子是如此之小<br />
<br />
5 有机体的活动需要精确的物理学定律<br />
<br />
6 物理学定律是以原子统计力学为根据的,因而只是近似的<br />
<br />
7 它们的精确性是以大量原子的介入为基础的第一个例子(顺磁性)<br />
8 第二个例子(布朗行动,扩散)<br />
<br />
9 第三个例子(测量准确性的限度)<br />
<br />
10 n律<br />
<br />
第二章 遗传机制<br />
<br />
1 经典物理学家那些绝非无关紧要的设想是错误的<br />
<br />
2 遗传的密码本(染色体)<br />
<br />
3 通过细胞分裂(有丝分裂)的个体生长<br />
<br />
4 在有丝分裂中每个梁色体是被复制的<br />
<br />
5 染色体数减半的细胞分裂(减数分裂)和受精(配子与合)<br />
<br />
.6 单倍体个体<br />
<br />
7 减数分裂的突出性质<br />
<br />
8 交换,特性的定位<br />
<br />
9 基因的最大尺度<br />
<br />
10 小的数量<br />
<br />
11 持久性<br />
<br />
第三章 突皮<br />
<br />
1 “跳跃式”的突变——自然选择的工作场地<br />
<br />
2 它们生育同样的后代,即它们是完全地遗传下来了<br />
<br />
3 定位,隐性和显性<br />
<br />
4 介绍一些术语<br />
<br />
5 近亲繁殖的有害效应<br />
<br />
6 一般的和历史的陈述<br />
<br />
7 突变作为一种罕有事件的必要性<br />
<br />
8 x射线诱发的突变<br />
<br />
9 第一定律,突变是个单一性事件<br />
<br />
10 第二定律,事件的局域性<br />
<br />
第四章 量子力学的证据<br />
<br />
1.经典物理学无法解释的持久性<br />
<br />
2.可以用量子论来解释<br />
<br />
3.量子论一不连续状态一量子跃迁<br />
<br />
4.分子<br />
<br />
5.分子的稳定性有赖于温度<br />
<br />
6.数学的插曲<br />
<br />
7.第一个修正<br />
<br />
8.第二个修正<br />
<br />
第五章 对德尔勃吕克模型的讨论和检验..<br />
<br />
1.遗传物质的一般图像<br />
<br />
2.图像的独特性<br />
<br />
3.一些传统的错误概念<br />
<br />
4.物质的不同的“态”<br />
<br />
5.真正重要的区别<br />
<br />
6.非周期性的固体<br />
<br />
7.压缩在微型密码里的丰富内容<br />
<br />
8.与实验事实作比较:稳定度;突变的不连续性<br />
<br />
9.自然选择基因的稳定性<br />
<br />
10.突变体的稳定性有时是较低的<br />
<br />
11.不稳定基因受温度的影响小于稳定基因<br />
<br />
12.x射线是如何诱发突变的<br />
<br />
13.x射线的效率并不依赖于自发突变率<br />
<br />
14.回复突变<br />
<br />
第六章 有序,无序和熵<br />
<br />
1.一个从模型得出的值得注意的普遍结论<br />
<br />
2.由序导出序<br />
<br />
3.生命物质避免了向平衡衰退<br />
<br />
4.以“负熵”为生<br />
<br />
5.熵是什么<br />
<br />
6.熵的统计学意义<br />
<br />
7.从环境中抽取“序”来维持组织<br />
<br />
第七章 生命是以物理学定律为基础的吗<br />
<br />
1.在有机体中可能有的新定律<br />
<br />
2.生物学状况的评述<br />
<br />
3.物理学状况的综述<br />
<br />
4.明显的对比<br />
<br />
5.产生序的两种方式<br />
<br />
6.新原理并不违背物理学<br />
<br />
7.钟的运动<br />
<br />
8.钟表装置毕竟是统计学的<br />
<br />
9.能斯特定理<br />
<br />
10.摆钟实际上可看做在绝对零度下工作<br />
<br />
11.钟表装置与有机体之间的关系<br />
<br />
后记 决定论与自由意志<br />
<br />
第二部分 意识和物质<br />
<br />
第一章 意识的物质基础<br />
<br />
1.问题<br />
<br />
2.一个尝试性的答案<br />
<br />
3.伦理观<br />
<br />
第二章 了解未来<br />
<br />
1.生物发展的死路<br />
<br />
2.达尔文主义的明显的悲观情绪<br />
<br />
3.行为影响选择<br />
<br />
4.伪拉马克主义<br />
<br />
5.习惯和技能的遗传固定<br />
<br />
6.智力进化的危险<br />
<br />
第三章 客观性原则<br />
<br />
第四章 算术悖论:意识的单一性<br />
<br />
第五章 科学与宗教<br />
<br />
第六章 感知的奥秘<br />
<br />
自传<br />
<br />
译后记..<br />
<br />
<br />
<br />
==复杂==<br />
<br />
[[File:s1066661个.png|300px]]<br />
<br />
*作 者: [美] 米歇尔·沃尔德罗普 <br />
*出版社: 生活·读书·新知三联书店<br />
*副标题: 诞生于秩序与混沌边缘的科学<br />
*原作名: Complexity: The Emerging Science at the Edge of Order and Chaos<br />
*译 者: 陈玲 <br />
*出版年: 1997-04<br />
*页数: 505<br />
*定价: 26.00元<br />
*装帧: 平装<br />
*丛书: 科学人文<br />
*ISBN: 9787108010056<br />
<br />
===内容简介===<br />
<br />
这部书叙述一群美国科学家如何开创“21世纪的科学”的故事,对正在形成的科学的复杂体系做了深入浅出的描述。介绍了“一场新的启蒙运动”。故事是,美国的一些不同领域的科学家们越来越无法忍受自牛顿以来一直主导科学的线性和还原的思想束缚。他们在各自领域发现,这个世界是一个相互关联和相互进化的世界,并非线性发展的,并非现有科学可以解释清楚的。他们认为这个世界上不仅存在着混沌,也存在着结构和秩序,他们逐渐将自己的新发现和新观点聚集起来,共同努力形成对整个自然界,对人类社会的一个全新的认识。<br />
<br />
<br />
===目录===<br />
<br />
目录<br />
<br />
概述<br />
<br />
第一章 爱尔兰理念的英雄<br />
<br />
第二章 老帅倒戈<br />
<br />
第三章 造物主的秘密<br />
<br />
第四章“你们真的相信这套?<br />
<br />
第五章 游戏高手<br />
<br />
第六章 混沌边缘的生命<br />
<br />
第七章 玻璃房中的农民经济<br />
<br />
第八章 等待卡诺<br />
<br />
第九章 乘胜前进<br />
<br />
==长尾理论==<br />
<br />
[[File:s1914890个.png|300px]]<br />
<br />
* 作者: [美] 克里斯·安德森 <br />
*出版社: 中信出版社<br />
*译者: 乔江涛 <br />
*出版年: 2006-12<br />
*页数: 235<br />
*定价: 35.00元<br />
*装帧: 平装<br />
*ISBN: 9787508607245<br />
<br />
===内容简介===<br />
<br />
书中阐述,商业和文化的未来不在于传统需求曲线上那个代表“畅销商品”(hits)的头部; 而是那条代表“冷门商品”(misses)经常为人遗忘的长尾。 举例来说, 一家大型书店通常可摆放10万本书,但亚马逊网络书店的图书销售额中,有四分之一来自排名10万以后的书籍。这些“冷门”书籍的销售比例正以高速成长,预估未来可占整体书市的一半。<br />
这意味着消费者在面对无限的选择时,真正想要的东西、和想要取得的渠道都出现了重大的变化,一套崭新的商业模式也跟着崛起。<br />
传统的市场曲线是符合80/20铁律的,为了抢夺那带来80% 利润的畅销品市场,我们厮杀得天昏地暗,但是我们所谓的热门商品正越来越名不副实,比如说黄金电视节目的收视率几十年来一直在萎缩,若放在1970年,现在的一档最佳节目恐怕连前10名之列都难以进入。简言之,尽管我们仍然对大热门着迷,但它们的经济力量已经今非昔比。那么,那些反复无常的消费者们已经转向了什么地方?答案并非唯一。他们散向了四面八方,因为市场已经分化成了无数不同的领域。互联网的出现改变了这种局面,使得99%的商品都有机会进行销售,市场曲线中那条长长的尾部(所谓的利基产品)也咸鱼翻身,成为我们可以寄予厚望的新的利润增长点。<br />
<br />
===作者简介===<br />
<br />
克里斯·安德森(Chris Anderson) 自2001年起担任美国《连线》杂志(Wired)总编辑。在他的领导之下,《连线》杂志五度获得“美国国家杂志奖”(National Magazine Award)的提名,并在2005年获得“卓越杂志奖”(General Excellence)金奖。<br />
<br />
<br />
===目录===<br />
<br />
序言<br />
<br />
第1章 长尾市场<br />
<br />
技术正在将大规模市场转化成无数小市场<br />
<br />
第2章 大热门的兴衰起伏<br />
<br />
大一统文化只是例外,不是规则<br />
<br />
第3章 长尾的三种力量<br />
<br />
制造它,传播它,帮助我找到它<br />
<br />
第4章 新生产者<br />
<br />
万不可小视数以百万计的业余生产者<br />
<br />
第5章 新市场<br />
<br />
从头部到长尾<br />
<br />
第6章 新时尚领军人<br />
<br />
如果蚂蚁也有扩音器,它们会说些什么?<br />
<br />
第7章 长尾经济学<br />
<br />
匮乏世界、丰饶世界与80/20法则的灭亡<br />
<br />
第8章 货架争夺战<br />
<br />
有限货架的世界<br />
<br />
第9章 选择的天堂<br />
<br />
我们正在进入下一个无限选择的时代,而且这是件好事<br />
<br />
第10章 利基文化<br />
<br />
长尾世界是怎样的?<br />
<br />
第11章 无限的荧屏<br />
<br />
电视之后的视频<br />
<br />
第12章 娱乐业之外<br />
<br />
长尾触角能伸多远<br />
<br />
第13章 长尾法则<br />
<br />
怎样创造一个消费天堂?<br />
<br />
尾声:明天的长尾<br />
<br />
致谢<br />
<br />
专家推荐一 从蓝海战略到长尾理论<br />
<br />
专家推荐二 尾巴有多长<br />
<br />
<br />
<br />
==虚实世界==<br />
<br />
[[File:38407af2.png|300px]]<br />
<br />
*书 名 : 虚实世界-计算机仿真如何改变科学的疆域<br />
*作 者 : [美]约翰.L.卡斯蒂 翻译:王千详、权利宁<br />
*出 版 : 上海科学教育出版社<br />
<br />
===内容简介===<br />
《虚实世界》“哲人石丛书”之一。本书是“当代最了不起的科学作家”卡斯蒂讲述仿真学的力作。作为正在引发科学革命的计算机仿真,不是基于直接观察实验,而是基于从真实空间向虚拟空间的映射。从人工生命到地缘政治游戏,从股市心理到总统提名悖论,《虚实世界》引领读者穿越硅化微世界,探索复杂自适应系统新疆域。计算机仿真世界是否“真实”和能达到何种程度的真实,回答这些饶有趣味的问题,将开辟21世纪科学发现的新天地。<br />
<br />
<br />
===推荐理由===<br />
这本书最大的长处就是给读者介绍了很多非常有名的模拟程序,包括著名的tierra(机器中进化的人工生命), 人工股市、transim(交通模拟系统)等等,而且讲得通俗易懂,你一下就能明白整个系统的设计思路,并且书后还附有了各种模拟程序的参考文献和网址,大家可以借鉴借鉴。<br />
该书最大的缺点是连贯性不够,虽然作者探讨了包括数学中的悖论、不可能定理、停机问题等等很深奥的问题,并且讲了一些一般复杂适应系统的通有规律,但是我却很难看出来这些东西之间的联系是什么,也可能是翻译不好的缘故吧。不过从开阔眼界这个方面,我觉得这本书还是很值得读一读的<br />
<br />
<br />
<br />
==沙地上的图案==<br />
<br />
[[File:df51392.png|300px]]<br />
<br />
*书 名 : 沙地上的图案- 计算机、复杂和生命<br />
*作 者 : [澳]特瑞·波索马特尔大卫·格林著<br />
*出 版 : 江西教育出版社<br />
<br />
===内容简介===<br />
生命究竟是什么?难道生命无非是一种特殊而微妙的碳水化合物? 还是某种更微妙的东西?植物、动物、大脑、恒星乃至银河,宇宙中为什么会存在这样一种令人惊叹的精妙的结构?现在,产生了一门新科学——关于复杂性的科学,将试图解决这一切。本书作者向我们讲述了这个世界中秩序与混乱的法则,并介绍了复杂性学说在神经系统、环境处理以及生物学和计算机领域取得的突破性的研究成果。本书的重点在于揭示复杂性的真谛及其对我们日常生活的影响。书中运用了大量具体、翔实的事例——从海星到忙碌奔波的推销员,从汽车事故到大脑的工作流程。相信读者朋友们读后能以一种新的见解去审视我们身边的大千世界。<br />
<br />
<br />
===本书目录===<br />
<br />
第一章 复杂性的处理;<br />
<br />
第二章 计算;<br />
<br />
第三章 殊途同归复杂性;<br />
<br />
第四章 自然界的不平衡;<br />
<br />
第五章 自然界的本质;<br />
<br />
第六章 良好关系的重要性;<br />
<br />
第七章 沙地上的图案;<br />
<br />
第八章 计算机的影响和后果;<br />
<br />
第九章 因特网:高速公路还是羊肠小道;<br />
<br />
第十章 复杂性与生命。<br />
<br />
<br />
<br />
==科学新领域的探索==<br />
<br />
[[File:77f5ef8.png|300px]]<br />
<br />
*书 名 : 科学新领域的探索<br />
*作 者 : 斯图亚特.考夫曼<br />
*译 者 : 池丽平<br />
*出 版 : 湖南科学技术出版社 2004年5月<br />
<br />
===内容推简===<br />
<br />
这本书是刚刚2004年5月出版的,英文版也不过是2000年推出的。因而相对比较新。在这本书中,作者主要向给大家传达一个信息:目前,一个崭新的科学逐渐浮出了水面。这有可能是继复杂性科学革命之后的新一轮的大规模科学创新活动。作者自己也承认,在这片新领域中,更多的是它的一些设想,而非确凿的科学证据,然而他已经瞥见了这背后蕴藏的巨大的科学前景。<br />
<br />
生命究竟是什么?自从薛定鄂的名著《什么是生命》问世以来,人们正在逐渐逼近生命本质的最终答案,但是无论是分子生物学还是人工生命都不能彻底回答这个问题,似乎还差那么一点点。作者就是从这个问题出发开始尝试给出生命的确切定义。他上来就提到:细菌会沿着葡萄糖浓度梯度自动游向高浓度的地方,我们显然知道它具有自主性、目的性,然而这种自主性、目的性究竟是什么呢?<br />
为了回答这个问题,作者开始广泛探讨生物科学、化学、热力学、宇宙学、经济社会科学等等广阔的领域,并尝试作了一些回答,什么是生命?一个自我维持并能够繁殖自身的包含至少一个功循环的组织就是生命,他就是活物。这个定义包含了生命的自我繁殖和新陈代谢两个主要方面。因而,考夫曼提出了“广义生物学”这个名词。<br />
<br />
另外,作者还大胆假设热力学第四定律的存在可能性,非平衡系统总是朝向尽量多样化尽量复杂化的方向发展,这被他成为是临近可能性的不断膨胀。在考夫曼与著名的宇宙学家李.斯莫林的讨论中,还逐渐认识到宇宙本身就是一个类似生物圈的系统,自己构造了自身并维持自己存在下去。<br />
推荐这本书,希望大家也能够体会到这一新领域中令人激动人心的地方。<br />
<br />
<br />
<br />
==谜米机器----谜米 自我 幻觉==<br />
<br />
[[File:mimi.png|300px]]<br />
<br />
*书 名 : 谜米机器----谜米 自我 幻觉<br />
*作 者 : 英国)苏珊·布莱克摩尔<br />
*译 者 : 高申春 吴友军 许波<br />
*出 版 : 吉林人民出版社2011年1月1日 第2版<br />
<br />
===内容简介===<br />
《谜米机器》视野开阔,背景恢弘,引人入胜。它结束于直面我们人类本性的最深刻的问题。这些问题的核心,乃是内在于我们每一个人心中的自我本性。正是这个自我构成了我们的意识核心,体验着我们心灵深处的情感,拥有着我们的记忆和信仰,并为我们的种种生活任务作出抉择。苏珊·布莱克摩尔的结论语出惊人:那个内在的自我,那个“内在的我”,其实不过是一个幻觉而已,不过是谜米为了它们自身的复制而虚构出来的一个幻影。<br />
<br />
===目录===<br />
序<br />
<br />
前言<br />
<br />
第一章 神奇的造化<br />
<br />
第二章 放之四海而皆准的达尔丈主义<br />
<br />
第三章 文化的进化<br />
<br />
第四章 从谜米的观点看世界<br />
<br />
第五章 有关谜米的三个问题<br />
<br />
第六章 容量巨大的人脑<br />
<br />
第七章 语言的起源<br />
<br />
第八章 谜米——基因的共同进化<br />
<br />
第九章 社会生物学的限度<br />
<br />
第十章 “是一个有机体救了我的命”<br />
<br />
第十一章 现代世界中的性<br />
<br />
第十二章 利他行为的谜米学阐释<br />
<br />
第十三章 利他主义骗局<br />
<br />
第十四章 新时代的谜米<br />
<br />
第十五章 宗教作为谜米复合体<br />
<br />
第十六章 进入因特网<br />
<br />
第十七章 终极的谜米复合体<br />
<br />
第十八章 超越谜米竞争<br />
<br />
===推荐理由===<br />
一位英国的大学教授回忆道:他有一个很有个性的女学生,每当他在课堂上向她提问的时候,“她总是紧闭双眼,深深地低下头,一会儿之后,又忽然地抬起头,睁开双眼,极为流利而聪明地回答我的问题。”有一天中午,他和几位同事共进午餐。为了活跃气氛,这位教授特意在回答一位同事的提问前模仿了这位学生的表现方式,并表明这是他的一名学生在回答问题之前的习惯。在座的同事中有一位是牛津大学著名哲学家。他看到模仿之后不假思索地脱口而出:“维特根斯坦!”并问:“她是不是姓……?”教授答:“是的”。他接着说:“我想应该是的。她的父母都是专业哲学家,而且都是维特根斯坦的忠实信徒…… "<br />
<br />
这就是meme(谜米)。“谜米”是一个新词,根据牛津英语词典的解释,meme:An element of culture that may be considered to be passed on by non-genetic means,esp.imitation.(谜米:文化的基本单位,通过非遗传的方式、特别是模仿而得到传递)“谜米”一词最早出现于理查德·道金斯(Richard Dawkins)于1976年出版的畅销著作《自私的基因》(The Selfish Gene)中。道金斯是牛津大学的一位著名的动物学家,也就是本文开头故事中的那位进行模仿的教授。在这本书中,道金斯使当时影响日甚的一个观点更趋普及化:进化的过程最好从基因之间的互相竞争的角度来理解。在过去,生物学家总是从“种”的角度来谈论进化的机制,到了60年代人们开始产生疑问,并提出从“基因的观点”来看待进化过程,即基因是进化的基本单位,而生物体(人)只不过是“基因传承和繁衍自身的工具”——这就是颇具刺激性的“自私基因论”(selfish-gene theory)。<br />
<br />
在《自私的基因》一书的末尾,道金斯提问道:在文化领域是否存在着类似基因在生物进化中所起作用的东西呢?他的回答是“有”的。为此他仿效“gene”创造了“meme”作为社会遗传的基本单位。道金斯特别指出,所谓“自私的基因”不是必然理解为DNA意义上的基因,它不过是进化过程的一个偶然的伴生产物。“自然选择的真实单位,乃是任何形式的复制因子,是任何形式的能够进行自我拷贝的单元”。按照道金斯的观点,除了DNA以外,已经产生了另外一种复制因子,这就是“谜米”(文化基因)。<br />
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这无疑是一个大胆的假说。这里要介绍的《谜米机器》(The Meme Machine)就是一本大力阐发“谜米”思想的新作,作者苏珊·布莱克莫尔博士(Susan Blackmore)则是道金斯的一位女学生。不过,学生比老师走得更远。在她看来,正如基因之间相互竞争着,自私地、不顾一切地要进入到下一代的身体之中,最终决定了生物世界的格局及其结构;与此类似,谜米之间相互竞争着,自私地、不顾一切地要进入到另一个人的大脑、另一本书、另一个对象之中,这最终决定了我们的文化以及我们的心理结构。按照这一思路,“谜米”观念实际上已经发展为一种独立的关于人类文化的全新理论。<br />
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作为一种新的研究纲领(正如达尔文进化论、弗洛伊德精神分析学一样),自然要展示它的全面力量(如果它果真有的话)。在本书中,苏珊·布莱克莫尔确实致力于“从谜米的观点”回答一系列激动人心的重大理论问题:人类心理的进化过程是怎样的?人脑的巨大容量是如何产生的?语言是怎样起源的?它的存在有什么用?“自我”意识是怎样产生的?“自我”的本质是什么?究竟是什么使情侣之间互相吸引?为什么有些声音总萦绕于脑海而驱之不散,并将我们折磨地睡不着?究竟是什么使你感到幸福?濒死体验是怎么回事……<br />
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她的答案同样也是令人震惊的。她对“自我”问题提供了如下的回答:所谓“内在的自我”,还有我们一直以来所关注的身份、人格等,其实不过是一个幻觉而已,不过是谜米为了它们自身的复制而虚构出来的一个幻影。这一观点,正如弗洛伊德的无意识理论一样,无疑将给我们的心理带来极大的冲击和震撼——当然,这也许不过是一个“幻觉”而已! 转自:《中华读书报》<br />
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理查德·道金斯,《自私的基因》,“支点丛书”,吉林人民出版社,24.00元。<br />
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苏珊·布莱克莫尔,《谜米机器》,“支点丛书”,吉林人民出版社,2001年,28.00元。<br />
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==隐秩序:适应性造就复杂性==<br />
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* 作者:约翰.荷兰德(John Holland),翻译:周晓牧、韩晖<br />
* 出版社:上海科学教育出版社<br />
* 出版年: 2000-08<br />
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===简介===<br />
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像艾滋病一类疾病为何能够摧毁免疫系统?像纽约、东京这样的大城市如何能够不间断地保障食品、医疗、服饰和数百万种居民必需品的供给?这类高度复杂系统的运作仍然是一个谜。但是通过霍兰及其同事在圣菲研究所和密歇根大学的工作,现在已经接近找到一种解答。作为遗传算法之父和复杂性新科学的先驱者之一,霍兰从一开始就处于复杂适应系统(CAS)这一新兴研究领域的中心。这部里程碑式著作为这一崭新领域首次提供了一种协调一致的综合,展示了霍兰的独特洞见。本书强调寻找支配CAS行为的一般原理,注重扩展众多科学家的直觉。书中提供了一个适用于全部CAS的计算机模型。霍兰通过描述我们能够做什么,总结了如何增强对CAS的理论认识。他提出的若干理论方法,可以指导人们对付耗尽资源、置我们世界于危险境地的棘手CAS问题。<br />
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===书评===<br />
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很早以前就听说过John Holland这个名字了,因为他的遗传算法在国内学术界早已经闻名遐迩。然而,通过阅读《隐秩序》这本书才让我了解到,John Holland的学术贡献不仅仅是遗传算法这样一个比较狭窄的算法领域,而是一个全新的学科复杂适应系统CAS,甚至是一种西方科学思想的全新世界观:一种进化的、适应性的、柔性的世界。 <br />
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1、基本元素 <br />
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纽约市中心的普通的一天,小女孩彼得逊走进了她喜欢的商店,直奔一排货架,毫不犹豫地拿起了一瓶她喜欢吃的腌鲱鱼……。然而小女孩从不用担心她喜欢的东西不在那,因为全世界的超级市场几乎都可以精确地把居民需要的成千上万的形形色色商品送到市场中、货架上。也许我们对这一现象早已经司空见惯,然而仔细思考里面却存在着一个很大的谜题:是谁安排了这一切呢?是什么机制使得那么多商品恰到好处地供应到货架上?经济系统为什么可以自发调节?从这样一个司空见惯的小事情,John Holland开始引领我们进入了CAS(复杂适应系统)的世界。接下来,Holland开始展现它非凡的知识和才华,从免疫系统到神经网络,从股票市场到热带雨林。哇,原来CAS的胃口这么大,它面向的不再是一两个数学定理的证明和无穷、繁琐的生物学实验,而是我们这个大千世界,一个几乎涉猎所有学科的广阔学术空间。 <br />
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这一章的一个基本点就是Holland教我们用一种统一的视角来看待所有的复杂适应系统。中国有句老话:隔行如隔山,一个搞经济学的人不会过问生物学的研究进展,搞计算机的几乎不关心政治。西方的科学研究方法教会了我们分类法,于是我们把学科也越分越细,然而CAS的诞生呼吁我们,是时候重新综合地看待所有学科了。那么,一般的复杂系统具有什么样的共同特征呢?首先,所有这些系统都是由大量被称为主体的元素组成的系统,这些主体整体能够具备第一章提到的聚集、非线性、流、多样性这四个特性,每个主体都具备内部模型、标识、积木这三种机制。 <br />
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根据我的理解,Holland这里所说的特性就是指所有的复杂适应系统所能反映出的客观特点和性质,它们是这些系统从宏观的角度来看所普遍具有的现象。而机制则说的是这些系统的内部原因,即基本上所有复杂系统中的个体都会遵循这样的三种普遍使用的规则。这样机制制约的个体相互组合就形成了具备四种特性的复杂系统。 <br />
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进一步,根据Holland提出的这7点,我们能够勾画出这样一种图景:若干小的细胞主体四处游走开始扎堆\"聚集\"到一起,并且它们之间发生着各种各样的复杂的\"非线性\"相互作用关系。由于每个细胞体都是由更小的大量的\"积木\"单元组合而成的,因此细胞体能够利用这些积木感知并操作它们的外在世界。它们通过给环境进行\"内部模型\"的建立而形成关于这个世界的一系列假设和预测,在这些假设和预测的共同作用下,细胞会不停学习从而完成自己的适应进化。然而细胞们聚集成的组织太大了,它会占据很大的空间区域,而空间区域的不同就会造成每个小细胞们的局部环境的不同。有的小细胞的环境可能水多一些,有些可能充满了有害物质,有些则可能营养丰富。这就导致了虽然小细胞们可能在开始的时候内部基础非常相似,然而却由于后天的环境不同而形成了完全不同的适应性结果。这就是\"多样性\"产生的基础。个体的多样化还进一步造成了这些个体细胞相互作用关系的多样化,于是非线性作用进一步发挥威力,不断创造各种新的生态位,而进一步催生组织的个体的多样性。 然而,这个时候组织要想进一步发展,则新的问题出现了。这就是个体太过多样化了,差异太大了,然而组织又要形成为一个统一的整体,必须有某种机制来抵消这种多样化,减少组织内各个部分之间的差异。这怎么办呢?有两种方法解决,一种是\"标识\",一种是\"流\"。首先,随着细胞的多样化增加,每个细胞所需要处理的信息就要增多,每个细胞要跟那么多不一样的细胞打交道显然是一件很痛苦的事儿。他们必须学会偷懒,也就是给那么多繁杂的细胞进行归类,给每个细胞贴标签,这就是个体的\"标识\"机制。其实,我们人类就是这么干的,我们常常会把其他人分成三六九等,其实就是给人贴标签。然而仅仅贴标签只不过是降低了个体处理信息的复杂性,然而组织整体要想存在还必须形成某种统一的东西,这就是流。流将所有的细胞重新统一成为一个整体,从而保证了组织的存在基础。在细胞和细胞之间开始接触的时候,他们就会发生物质和信息的交换,然而这些交换仅仅构成了一些局部的小的流动,随着系统进一步发展,各个小的流动开始汇合而形成一些大的贯穿整个组织的洪流。于是资源开始形成一种新的共同基础(好比是人体的血液),这股流流遍全身维护组织整体的存在。就这样,小细胞们构成了新一层次的生命体:组织。接下来,组织又成为了新一层面的细胞,组织和组织之间在发生相似的故事组织成更大的个体……。 <br />
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当然,这个图景仅仅是我自己的一个想象,Holland的脑中是否产生了这个动画?我不得而知,但我个人感觉,根据这个图景,Holland所述的7个基本点及其相互之间的关系变得更清楚了。 <br />
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2、适应性主体 <br />
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Holland带我们在复杂适应系统各个领域神游了一番以后,突然板起脸来说:“好了,别光顾得好玩,该来点真格的了!”。这一章开始展开了计算机模型的庞大攻势。也许到了这一章,数理基础薄弱、甚至数学物理学得很好却不熟悉计算机尤其是人工智能的人开始败下阵来了。然而,Holland毕竟是搞计算机出身,而且曾经参与过很早很早的IBM商业计算机的设计(在那个时候,摸过计算机的人也没有几个),所以他不可能不展示他对于计算机建模的深刻见解。 <br />
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上一章Holland抽出了所有复杂适应系统的共性,我们已经知道了what,接下来我们自然要问,how? 具体就是怎么来研究呢?这个时候,holland和大多数SFI(圣塔菲,Santa Fe Institute)学派的学者都会跟传统数学说\"no\",我们需要新的东西,这就是“计算机模型”,在这一章,Holland就是要告诉我们计算机模型是如何帮助我们理解复杂适应系统的。<br />
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Holland的研究思路是不忙对复杂系统的整体一下子建立大的模型,那是一个浩瀚的工程。而是从CAS中相对简单的个体出发,也就是我们上面提到的简单得多的细胞出发。在机器中建立这些个体的模型,然后让这群个体在计算机中相互作用而生成复杂系统的动态。于是接下来的一个关键问题就是如何建立每个主体(Agent)的模型。这可是Holland的拿手好戏,自从60年代以来,Holland已经几乎独立的发展了一整套建立适应性的Agent的计算机方法。这就是本章的主题。 <br />
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我认为,这一章其实可以分成两大部分,一部分是主体,另一部分是适应性。 首先,我们需要考虑的是,一个能够根据环境信息而进行决策和行动的主体。这是人工智能领域研究的问题。早期的人工智能已经提供了很多很多种建立这种主体的方法,包括什么慎思结构、神经网络等等。然而Holland没有采取那些繁杂的模型,而是用了一种相对简单的基于规则的方法。什么是基于规则的方法?我们可以就把它理解为一种因果关系,或者一种条件反射。“如果有东西朝我移动,我就逃跑;如果那个东西很小我就把它吃掉。”这种规则系统具有足够的计算能力,它完全等价于一台通用计算机。然而,仅仅用规则来描述主体的行为似乎有些太简单了,在很多情况,主体处理的信息往往非常复杂,以至于不能用简单规则来还原。Holland真有新招,他不使用一个规则,而是用一组规则,每种规则还都不一样,而且在运行的时候,可能会有好多相互矛盾的规则同时激活。仅仅这一点:允许相互矛盾的规则同时激活就已经让很多搞传统人工智能的人大跌眼镜,因为人工智能一直强调的是逻辑性、前后协调性,他们会人为的消除系统中的非逻辑性。 <br />
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然而,当多个规则同时存在甚至相互矛盾的时候就会自然提出一个问题,究竟Agent应该采用哪个规则呢?这就需要用到Holland所说的信用分派机制,即给每个规则都分派一个信用来表示使用该规则的可能性。用过遗传算法的人都知道,遗传算法有一个关键的适应度函数,这里的信用就是适应度函数对每个规则进行评价。当系统运行起来以后,这个信用会动态地改变,也就是系统从外界得到反馈来改变信用。也就是说信用是一种反馈机制。 <br />
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在推理中人们常常把多条规则首尾相接到一起形成一个长长的推理链,这种机制也可以用Holland的系统中描述出来。同时Holland还发明了水桶连算法来解决长链上规则的信用分派问题。即Holland把每条规则比喻成市场上的能够自由买卖的主体,这些主体一方面交换着货物(执行的权利),另一方面货币(信用)会反向流动。 <br />
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其次,Agent还具有适应性,这种适应性来源于Agent内部的创新机制:遗传算法,这是Holland在60年代的时候就研究出来的结果。当所有搞人工智能的人都认为知识和推理非常重要的时候,Holland却认为学习和灵活适应才是最重要的。因此,他用自然进化的比喻来研究程序的自动进化。正是他这一开创性的成就,使得人工智能学界兴起了新的一派人工智能,即进化学派,同时也为后来的遗传编程、演化程序等方法创造了可能。将这两点和起来,也就是基于规则的Agent和遗传算法就构成了完整的Agent分类器系统模型。 <br />
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3、4、回声导致的涌现、回声模型的计算机模拟 <br />
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其实,前面两章的内容已经构成了整本书的精华所在。可以说前面两章是Holland对复杂适应系统的研究已取得的一些成果。它们已经能够构成一整套研究CAS的方法和理论的基础。用这两章的知识我们已经可以对大部分的复杂适应系统进行建模研究了。然而,Holland还没有停止,而是继续前进,讨论了一些甚至是现在也没有得到充分研究清楚的领域:即人工生命中的开放式进化。有很多人看完整本书也不一定明白Echo模型,甚至仅仅了解了前述两章的内容就认为懂得了Holland整个的思路。(我以前就是这样,直到最近又看了一遍《隐秩序》这本书才知道自己的无知和幼稚)。其实这两章的内容才算真正进入了研究CAS的正题。 <br />
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有了我们要研究的目标:一般的复杂适应系统,有了强有力的工具:计算机以及一整套关于适应性Agent的构造方法,我们是否就能够模拟任意一个复杂适应系统了呢?答案是:远远不能。看看我们还缺少什么? <br />
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(1)、隐性适应度函数 <br />
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无论是遗传算法还是分类器系统,对每个个体的选择都需要根据一个明确定义的适应度函数来进行。尤其当我们解决优化问题的时候,这种适应度函数是由优化问题本身定义好了。然而在现实的复杂适应系统中,对于每个主体来说(细胞、生命、经济人)都不存在一个预先定义好的适应度函数。也不存在着现成的优化问题让个体去寻求最优解。复杂系统中存在的仅仅有不停的变化、不停的适应。因此,我们要想真正理解复杂适应系统就不能用原来的适应度函数,至少不能用显式的、固定死的适应度函数。 <br />
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(2)、个体基因发育出来的细胞多样性 <br />
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考虑一个受精卵发育成成体的过程,我们会发现,原始的受精卵细胞通过不断的分裂、增殖能够长出复杂的生命个体。更有意思的是,所有个体细胞都具有相同的基因,这些基因序列在不同的环境下却能够有序地分裂成异常不同的细胞体。比如人的皮肤细胞和脑神经元细胞无论从外形还是功能上来说都存在着很大的差异,但他们都具有相同的染色体。也就是说,如果我们把DNA序列比喻成计算机代码的话,那么该代码序列指导合成蛋白质的过程就是计算机计算DNA程序的过程。相同的DNA序列发育成不同的细胞就意味着同一段代码在不同的计算机环境中运行需要得到完全不同的计算结果。这显然是与我们目前的计算机程序不符的。而无论是生命个体的发育、生态系统的产生还是人类社会系统的生长都存在着类似的个体发生问题,这是用一般的方法不能解决的。 <br />
<br />
(3)、多层级结构 <br />
<br />
自然界的复杂系统普遍存在着层级结构,细胞->器官->生命->物种->生态,人->组织->单位->国家->人类社会,然而从现有的技术和理论框架出发我们还不足以描述这种层级结构。 <br />
<br />
(4)、资源的生产、交换及其流动 <br />
<br />
现实中的生命个体的各个部分之间还能进行资源的交换。而且每个个体就像一个独立的工厂可以根据不同的输入资源变化形成新的资源,这些资源之间能够运动而形成流。这一过程也是在现有模型中不容易建模的一个关键。 <br />
<br />
基于上述这些问题的考虑,Holland提出了这个echo模型,并提出了若干方案希望该模型能够模拟所有这些现象。这些问题也是目前人工生命中开放式进化生态系统的研究重点。这类问题是如此深奥以至于它触及到了自然进化的本质,又是如此另类,以至于它远远超越了我们同时代的许多科学问题的提问方式。 <br />
<br />
然而,可惜的是,Holland的Echo模型在《隐秩序》这本书里仅仅做了建模的讨论,而没有更多计算机模拟的结果。据说直到现在人们也没有对Echo模型的所有方面都进行模拟研究。而且,让人不易理解的另一个方面就是Holland的Echo模型似乎和他第二章的Agent模型联系非常不紧密,基本就是两套完全不同的框架。 <br />
<br />
幸好,现在已经有好多可以替代Echo模型的开放进化系统,比如大名鼎鼎的Tierra,还有各种人工化学模型,然而所有这些模型肯定都没有达到《隐秩序》中描述的程度,对上面提出的3个问题也仅仅是部分解决了。假如人们真能够造一个完美的开放式进化系统,那么在本文1、基本元素那里提到的小细胞体构造大规模组织的整个动画过程应该能够在计算机模拟中看到。 <br />
<br />
5、通向理论 <br />
<br />
这一章自然是对整本书讨论内容的一个展望了。如果说第一章Holland提出了问题What,第二章到第四章讨论了How的问题,那么这一章显然是要讨论Why这个问题,也就是说,Holland最终想回答构成一切复杂适应系统的各种动态背后的基本原理是什么?请注意,Holland在这章里明确提出了数学的重要性,他说计算机模型仅仅是一些个案的研究,而我们最终要得到的目标显然是一种各个计算机模型背后的数学理论,因为只有数学才能真正抽象出我们想要的事物背后的机制。但很显然,Holland自己在论述这个问题的时候也显得有些力不从心,因为对CAS的理解还太初步,我们还远没有达到上升为一个通用理论的程度。我不知道SFI的其它科学家怎么想,至少对Holland来说,他并不是一味排斥数学的作用的,而实在是因为他还没有能力把他对复杂适应系统的认识抽象成数学的形式。看到这里,我很感动,因为Holland的治学态度是认真负责的,他并不想用一大堆谁都看不懂的数学来唬人,他希望先对复杂系统有了普遍认识之后,才把它抽象成数学的形式。<br />
<br />
<br />
===推荐理由===<br />
<br />
这是John Holland写的阐释复杂适应系统最重要的一本著作,书中给出了什么是复杂适应系统,它的特性和机制是什么,而且该书也是计算机建模与模拟方面的重要入门之作,一些经典的模型:例如囚徒困境、货币的起源、ECHO生态系统等都有所阐述。<br />
<br />
<br />
<br />
==宇宙为家(At Home in the universe)==<br />
<br />
[[File:at_home_in_the_universe.jpg|300px]]<br />
<br />
* 作者:斯图亚特·考夫曼(Kauffman Stuart)<br />
* 译者:李绍明 / 徐彬<br />
* 出版社:湖南科学技术出版社<br />
* 丛书:第一推动丛书<br />
<br />
===内容简介===<br />
<br />
达尔文提出进化论,指出生命一直在自然选择之下演进、变化,而非上帝创造之物;孟德尔通过实验,揭示出遗传因子在遗传、变异中起到的作用。然而,从原初的分子汤,到物种繁多的地球生态圈,这种演化并不仅仅是在自然环境的影响下和随机的基因突变中产生的,从最初时,内在的秩序已经产生,并在混沌的边缘前进壮大,我们是注定要来到这个宇宙的。<br />
<br />
供职于圣塔菲研究所(Santa Fe Institute [http://www.santafe.edu])的考夫曼将复杂性原理应用于生命演化过程的分析,揭示出自组织才是生命秩序的源头,自然选择从外部作用于表现出自发秩序的系统之上,就产生出了现在的我们。我们不是什么不可思议的事故,不是靠零敲碎打、东拼西凑而成的 —— 我们是足月分娩、注定要降临的。<br />
<br />
===推荐理由===<br />
<br />
进化论是很了不起的,但总让人觉得我们的出现太过于幸运,幸运到一片空虚。而本书告诉我们,生命系统本身就有一股力量,推动着自身的前进,而自然选择不过是在外部对前进方向进行调整而已。这种观点给了我们一种对于生命系统的更为整体的视角,同时也是了解复杂性原理的一本好书。<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E5%9B%9B%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.3%E6%9C%88%E6%96%87%E7%AB%A0)&diff=15177
复杂文摘翻译第四期-(摘自Complex Digest 2016.3月文章)
2020-10-14T14:13:16Z
<p>Thingamabob:创建页面,内容为“ == Fitness Landscape Epistasis And Recombination == March 1, 3:38 AM<br> From Complex Syst. 18, 1550026 (2015)<br> By MANUEL BELTRÁN DEL RÍO, CHRISTOPHER R. STEPH…”</p>
<hr />
<div><br />
== Fitness Landscape Epistasis And Recombination ==<br />
March 1, 3:38 AM<br><br />
From Complex Syst. 18, 1550026 (2015)<br><br />
By MANUEL BELTRÁN DEL RÍO, CHRISTOPHER R. STEPHENS, and DAVID A. ROSENBLUETH<br><br />
(Translated by -)<br><br />
<br />
''Homologous recombination is an important operator in the evolution of biological organisms. However, there is still no clear, generally accepted understanding of why it exists and under what circumstances it is useful. In this paper, we consider its utility in the context of an infinite population haploid model with selection and homologous recombination. We define utility in terms of two metrics — the increase in frequency of fit genotypes, and the increase in average population fitness, relative to those associated with selection only. Explicitly, we explore the full parameter space of a two-locus two-allele system, showing, as a function of the landscape and the initial population, that recombination is beneficial in terms of these metrics in two distinct regimes: a relatively landscape independent regime — the search regime — where recombination aids in the search for a fit genotype that is absent or at low frequency in the population; and the modular regime, where recombination allows for the juxtaposition of fit “modules” or Building Blocks (BBs). Thus, we conclude that the ubiquity and utility of recombination is intimately associated with the existence of modularity and redundancy in biological fitness landscapes.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1142/S0219525915500265<br />
<br />
== Relative Entropy in Biological Systems ==<br />
March 1, 4:27 AM<br><br />
From Entropy 2016, 18(2), 46<br><br />
By John C. Baez and Blake S. Pollard<br><br />
(Translated by -)<br><br />
<br />
''In this paper we review various information-theoretic characterizations of the approach to equilibrium in biological systems. The replicator equation, evolutionary game theory, Markov processes and chemical reaction networks all describe the dynamics of a population or probability distribution. Under suitable assumptions, the distribution will approach an equilibrium with the passage of time. Relative entropy—that is, the Kullback–Leibler divergence, or various generalizations of this—provides a quantitative measure of how far from equilibrium the system is. We explain various theorems that give conditions under which relative entropy is nonincreasing. In biochemical applications these results can be seen as versions of the Second Law of Thermodynamics, stating that free energy can never increase with the passage of time. In ecological applications, they make precise the notion that a population gains information from its environment as it approaches equilibrium.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.3390/e18020046<br />
<br />
== An Experimental Study of Segregation Mechanisms ==<br />
March 1, 5:32 AM<br><br />
From EPJ Data Science 2016, 5 :4 (27 February 2016)<br><br />
By Tsvetkova M, Nilsson O, Öhman C, Sumpter L, Sumpter D<br><br />
(Translated by -)<br><br />
<br />
''Segregation is widespread in all realms of human society. Several influential studies have argued that intolerance is not a prerequisite for a segregated society, and that segregation can arise even when people generally prefer diversity. We investigated this paradox experimentally, by letting groups of high-school students play four different real-time interactive games. Incentives for neighbor similarity produced segregation, but incentives for neighbor dissimilarity and neighborhood diversity prevented it. The participants continued to move while their game scores were below optimal, but their individual moves did not consistently take them to the best alternative position. These small differences between human and simulated agents produced different segregation patterns than previously predicted, thus challenging conclusions about segregation arising from these models.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1140/epjds/s13688-016-0065-5<br />
<br />
== Temporal Network Analysis of Literary Texts ==<br />
March 1, 5:08 PM<br><br />
From arxiv.org<br><br />
By Sandra D. Prado, Silvio R. Dahmen, Ana L.C. Bazzan, Padraig Mac Carron, Ralph Kenna<br><br />
(Translated by -)<br><br />
<br />
''We study temporal networks of characters in literature focusing on "Alice's Adventures in Wonderland" (1865) by Lewis Carroll and the anonymous "La Chanson de Roland" (around 1100). The former, one of the most influential pieces of nonsense literature ever written, describes the adventures of Alice in a fantasy world with logic plays interspersed along the narrative. The latter, a song of heroic deeds, depicts the Battle of Roncevaux in 778 A.D. during Charlemagne's campaign on the Iberian Peninsula. We apply methods recently developed by Taylor and coworkers \cite{Taylor+2015} to find time-averaged eigenvector centralities, Freeman indices and vitalities of characters. We show that temporal networks are more appropriate than static ones for studying stories, as they capture features that the time-independent approaches fail to yield.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1602.07275<br />
<br />
== The Research Space: using the career paths of scholars to predict the evolution of the research output of individuals, institutions, and nations ==<br />
March 1, 7:01 PM <br><br />
From arxiv.org<br><br />
By Miguel R. Guevara, Dominik Hartmann, Manuel Aristarán, Marcelo Mendoza, César A. Hidalgo<br><br />
(Translated by -)<br><br />
<br />
''In recent years scholars have built maps of science by connecting the academic fields that cite each other, are cited together, or that cite a similar literature. But since scholars cannot always publish in the fields they cite, or that cite them, these science maps are only rough proxies for the potential of a scholar, organization, or country, to enter a new academic field. Here we use a large dataset of scholarly publications disambiguated at the individual level to create a map of science-or research space-where links connect pairs of fields based on the probability that an individual has published in both of them. We find that the research space is a significantly more accurate predictor of the fields that individuals and organizations will enter in the future than citation based science maps. At the country level, however, the research space and citations based science maps are equally accurate. These findings show that data on career trajectories-the set of fields that individuals have previously published in-provide more accurate predictors of future research output for more focalized units-such as individuals or organizations-than citation based science maps.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1602.08409<br />
<br />
== Rate or Trade? Identifying Winning Ideas in Open Idea Sourcing ==<br />
March 3, 9:10 PM<br><br />
From Information Systems Research<br><br />
By Ivo Blohm, Christoph Riedl, Johann Füller, Jan Marco Leimeister<br><br />
(Translated by -)<br><br />
<br />
''Information technology (IT) has created new patterns of digitally-mediated collaboration that allow open sourcing of ideas for new products and services. These novel sociotechnical arrangements afford finely-grained manipulation of how tasks can be represented and have changed the way organizations ideate. In this paper, we investigate differences in behavioral decision-making resulting from IT-based support of open idea evaluation. We report results from a randomized experiment of 120 participants comparing IT-based decision-making support using a rating scale (representing a judgment task) and a preference market (representing a choice task). We find that the rating scale-based task invokes significantly higher perceived ease of use than the preference market-based task and that perceived ease of use mediates the effect of the task representation treatment on the users’ decision quality. Furthermore, we find that the understandability of ideas being evaluated, which we assess through the ideas’ readability, and the perception of the task’s variability moderate the strength of this mediation effect, which becomes stronger with increasing perceived task variability and decreasing understandability of the ideas. We contribute to the literature by explaining how perceptual differences of task representations for open idea evaluation affect the decision quality of users and translate into differences in mechanism accuracy. These results enhance our understanding of how crowdsourcing as a novel mode of value creation may effectively complement traditional work structures.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://pubsonline.informs.org/doi/abs/10.1287/isre.2015.0605<br />
<br />
<br />
== Living Cognitive Society: a 'digital' World of Views ==<br />
March 3, 9:47 PM<br><br />
From arxiv.org<br><br />
By Viktoras Veitas, David Weinbaum (Weaver)<br><br />
(Translated by -)<br><br />
<br />
''The current social reality is characterized by all-encompassing change, which disrupts existing social structures at all levels. Yet the prevailing view of society is based on the ontological primacy of stable hierarchical structures, which is no longer adequate.'' <br><br />
''We propose a conceptual framework for thinking about a dynamically changing social system: the Living Cognitive Society. Importantly, we show how it follows from a much broader philosophical framework, guided by the theory of individuation, which emphasizes the importance of relationships and interactive processes in the evolution of a system.'' <br><br />
''The framework addresses society as a living cognitive system -- an ecology of interacting social subsystems -- each of which is also a living cognitive system. We argue that this approach can help us to conceive sustainable social systems that will thrive in the circumstances of accelerating change. The Living Cognitive Society is explained in terms of its fluid structure, dynamics and the mechanisms at work. We then discuss the disruptive effects of Information and Communication Technologies on the mechanisms at work.'' <br><br />
''We conclude by delineating a major topic for future research -- distributed social governance -- which focuses on processes of coordination rather than on stable structures within global society.''<br><br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1602.08388<br />
<br />
== From neurons to epidemics: How trophic coherence affects spreading processes ==<br />
March 3, 10:48 PM<br><br />
From arxiv.org<br><br />
By Janis Klaise, Samuel Johnson<br><br />
(Translated by -)<br><br />
<br />
''Trophic coherence, a measure of the extent to which the nodes of a directed network are organised in levels, has recently been shown to be closely related to many structural and dynamical aspects of complex systems, including graph eigenspectra, the prevalence or absence of feed-back cycles, and linear stability. Furthermore, non-trivial trophic structures have been observed in networks of neurons, species, genes, metabolites, cellular signalling, concatenated words, P2P users, and world trade. Here we consider two simple yet apparently quite different dynamical models -- one a Susceptible-Infected-Susceptible (SIS) epidemic model adapted to include complex contagion, the other an Amari-Hopfield neural network -- and show that in both cases the related spreading processes are modulated in similar ways by the trophic coherence of the underlying networks. To do this, we propose a network assembly model which can generate structures with tunable trophic coherence, limiting in either perfectly stratified networks or random graphs. We find that trophic coherence can exert a qualitative change in spreading behaviour, determining whether a pulse of activity will percolate through the entire network or remain confined to a subset of nodes, and whether such activity will quickly die out or endure indefinitely. These results could be important for our understanding of phenomena such as epidemics, rumours, shocks to ecosystems, neuronal avalanches, and many other spreading processes.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.00670<br><br />
<br />
== Estimation and monitoring of city-to-city travel times using call detail records ==<br />
March 3, 11:26 PM<br><br />
From EPJ Data Science 2016 5:6<br><br />
By Rainer Kujala, Talayeh Aledavood and Jari Saramäki<br><br />
(Translated by -)<br><br />
<br />
''Whenever someone makes or receives a call on a mobile telephone, a Call Detail Record (CDR) is automatically generated by the operator for billing purposes. CDRs have a wide range of applications beyond billing, from social science to data-driven development. Recently, CDRs have been increasingly used to study human mobility, whose understanding is crucial e.g. for planning efficient transportation infrastructure. A major difficulty in analyzing human mobility using CDR data is that the location of a cell phone user is not recorded continuously but typically only when a call is initiated or a text message is sent. In this paper we address this problem, and develop a method for estimating travel times between cities based on CDRs that relies not on individual trajectories of people, but their collective statistical properties. We apply our method to data from Senegal, released by Sonatel and Orange for the 2014 Data for Development Challenge. We turn CDR mobility traces to estimates on travel times between Senegalese cities, filling an existing gap in knowledge. Moreover, the proposed method is shown to be highly valuable for monitoring travel conditions and their changes in near real-time, as demonstrated by measuring the decrease in travel times due to the opening of the Dakar-Diamniadio highway. Overall, our results indicate that it is possible to extract reliable de facto information on typical travel times that is useful for a variety of audiences ranging from casual travelers to transport infrastructure planners.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1140/epjds/s13688-016-0067-3<br />
<br><br />
== Women through the glass ceiling: gender asymmetries in Wikipedia ==<br />
March 4, 1:28 AM<br><br />
From EPJ Data Science 2016 5:5<br><br />
By Claudia Wagner, Eduardo Graells-Garrido, David Garcia and Filippo Menczer<br><br />
(Translated by -)<br><br />
<br />
''Contributing to the writing of history has never been as easy as it is today thanks to Wikipedia, a community-created encyclopedia that aims to document the world’s knowledge from a neutral point of view. Though everyone can participate it is well known that the editor community has a narrow diversity, with a majority of white male editors. While this participatory gender gap has been studied extensively in the literature, this work sets out to assess potential gender inequalities in Wikipedia articles along different dimensions: notability, topical focus, linguistic bias, structural properties, and meta-data presentation.''<br><br />
''We find that (i) women in Wikipedia are more notable than men, which we interpret as the outcome of a subtle glass ceiling effect; (ii) family-, gender-, and relationship-related topics are more present in biographies about women; (iii) linguistic bias manifests in Wikipedia since abstract terms tend to be used to describe positive aspects in the biographies of men and negative aspects in the biographies of women; and (iv) there are structural differences in terms of meta-data and hyperlinks, which have consequences for information-seeking activities. While some differences are expected, due to historical and social contexts, other differences are attributable to Wikipedia editors. The implications of such differences are discussed having Wikipedia contribution policies in mind. We hope that the present work will contribute to increased awareness about, first, gender issues in the content of Wikipedia, and second, the different levels on which gender biases can manifest on the Web.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1140/epjds/s13688-016-0066-4<br />
<br><br />
== Exploring the Space of Viable Configurations in a Model of Metabolism–Boundary Co-construction ==<br />
March 4, 3:33 AM<br><br />
From www.mitpressjournals.org<br><br />
By Eran Agmon, Alexander J. Gates, Valentin Churavy, Randall D. Beer<br><br />
(Translated by -)<br><br />
<br />
''We introduce a spatial model of concentration dynamics that supports the emergence of spatiotemporal inhomogeneities that engage in metabolism–boundary co-construction. These configurations exhibit disintegration following some perturbations, and self-repair in response to others. We define robustness as a viable configuration's tendency to return to its prior configuration in response to perturbations, and plasticity as a viable configuration's tendency to change to other viable configurations. These properties are demonstrated and quantified in the model, allowing us to map a space of viable configurations and their possible transitions. Combining robustness and plasticity provides a measure of viability as the average expected survival time under ongoing perturbation, and allows us to measure how viability is affected as the configuration undergoes transitions. The framework introduced here is independent of the specific model we used, and is applicable for quantifying robustness, plasticity, and viability in any computational model of artificial life that demonstrates the conditions for viability that we promote.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1140/epjds/s13688-016-0066-4<br />
<br><br />
<br />
== Flies as Ship Captains? Digital Evolution Unravels Selective Pressures to Avoid Collision in Drosophila ==<br />
March 4, 5:45 AM<br><br />
From arxiv.org<br><br />
By Ali Tehrani-Saleh, Christoph Adami<br><br />
(Translated by -)<br><br />
<br />
''Flies that walk in a covered planar arena on straight paths avoid colliding with each other, but which of the two flies stops is not random. High-throughput video observations, coupled with dedicated experiments with controlled robot flies have revealed that flies utilize the type of optic flow on their retina as a determinant of who should stop, a strategy also used by ship captains to determine which of two ships on a collision course should throw engines in reverse. We use digital evolution to test whether this strategy evolves when collision avoidance is the sole penalty. We find that the strategy does indeed evolve in a narrow range of cost/benefit ratios, for experiments in which the "regressive motion" cue is error free. We speculate that these stringent conditions may not be sufficient to evolve the strategy in real flies, pointing perhaps to auxiliary costs and benefits not modeled in our study.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.00802<br />
<br><br />
== Zika Virus: Endemic Versus Epidemic Dynamics and Implications for Disease Spread in the Americas ==<br />
March 4, 7:42 AM<br><br />
From biorxiv.org<br><br />
By Sharon Bewick, William F Fagan, Justin M Calabrese, Folashade Agusto<br><br />
(Translated by -)<br><br />
<br />
''Since being introduced into Brazil in 2014, Zika virus (ZIKV) has spread explosively across Central and South America. Although the symptoms of ZIKV are mild, recent evidence suggests a relationship between prenatal exposure to ZIKV and microcephaly. This has led to widespread panic, including travel alerts and warnings to avoid pregnancy. Because ZIKV is an emerging disease, response efforts are complicated by limited understanding of disease dynamics. To this end, we develop a novel state- and class-structured compartment model for ZIKV. Our model shows that the risk of prenatal ZIKV exposure should decrease dramatically following the initial wave of disease, reaching almost undetectable levels in endemic systems. Our model also suggests that efforts to reduce ZIKV prenatal exposures through mosquito management and avoidance may have minimal benefit, and may even result in increased risk of microcephaly in later years of an outbreak.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1101/041897<br />
<br><br />
<br />
== About 40% of economics experiments fail replication survey ==<br />
March 5, 4:07 PM<br><br />
From www.sciencemag.org<br><br />
By John Bohannon<br><br />
(Translated by -)<br><br />
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''When a massive replicability study in psychology was published last year, the results were, to some, shocking: 60% of the 100 experimental results failed to replicate. Now, the latest attempt to verify findings in the social sciences—this time with a small batch from experimental economics—also finds a substantial number of failed replications. Following the exact same protocols of the original studies, the researchers failed to reproduce the results in about 40% of cases.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1126/science.aaf4141<br />
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== Generalizing Moore ==<br />
March 5, 5:45 PM<br><br />
From Nature Physics 12, 200 (2016)<br><br />
By Mark Buchanan<br><br />
(Translated by -)<br><br />
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''Over the past few years, several independent teams of researchers have noticed something surprising in historical data on a broad set of technologies. Everyone, of course, knows about Moore's Law — for decades, the density of transistors on integrated circuits has doubled every two years, with computational speed advancing even faster. This spectacular record of improvement shows up in just about any metric. Much less known, however, is that this pattern of exponential advance isn't actually limited to electronics; it applies just as well to technologies ranging from cars or batteries to beer or nuclear power.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/nphys3685<br />
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== Keep-Left Behavior Induced by Asymmetrically Profiled Walls ==<br />
March 5, 9:34 PM<br><br />
From Phys. Rev. X 6, 011003 (2016)<br><br />
By C. L. N. Oliveira, A. P. Vieira, D. Helbing, J. S. Andrade, Jr., and H. J. Herrmann<br><br />
(Translated by -)<br><br />
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''Ensuring efficient pedestrian streams through transit corridors such as subway hallways is a problem of significant relevance to many cities. By modeling self-driven particles, scientists show that modulating the shape of a hallway’s walls might help to separate opposite pedestrian flows.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1103/PhysRevX.6.011003<br />
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== Complex Autocatalysis in Simple Chemistries ==<br />
March 6, 9:31 PM<br><br />
From www.mitpressjournals.org<br><br />
By Nathaniel Virgo, Takashi Ikegami, Simon McGregor<br><br />
(Translated by -)<br><br />
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''Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1162/ARTL_a_00195<br />
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== Zika and Other Potential Causes of Microcephaly in Brazil: Status March 8, 2016 | NECSI ==<br />
March 8, 6:10 PM<br><br />
From Status March 8, 2016, NECSI (2016)<br><br />
By Raphael Parens, Yaneer Bar-Yam, Zika and other potential causes of microcephaly in Brazil<br><br />
(Translated by -)<br><br />
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''We review the current information about causes of microcephaly in Brazil in 2015-6, including speculative ones, in order to provide the best possible clarity about the information that is available as of the publication date in order to advance the rapid response efforts. We review the leading candidate, Zika virus infections, the second candidate, the pesticide pyriproxifen, as well as DPT immunizations, and GM mosquitoes. Each of these candidates has been considered because of an increase at very roughly the time of the increase in microcephaly cases. The strongest evidence is in favor of Zika, through the observation of Zika virus in neural tissue, though a key piece of evidence is missing in the expected rise of cases in other locations, specifically Colombia. Evaluation of the potential role of pyriproxifen is difficult due to the limited number and nature of available studies, which should be revisited as they include some evidence for neurodevelopmental toxicity. The possibility of DPT immunizations of pregnant women as a factor is largely ruled out by an increase in immunization in countries in which microcephaly cases are not being reported. There is no direct evidence for GM mosquitoes as a cause. If there is a dramatic increase in cases of microcephaly in Columbia in the next three months, the case for Zika will be dramatically strengthened, and the case for pyriproxyfen and GM mosquitoes will be essentially ruled out. On the other hand if the cases do not materialize, Zika will essentially be ruled out and pyriproxyfen would become the strongest case with GM mosquitoes a speculative alternative along with other environmental toxins.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://necsi.edu/research/social/pandemics/zikacauses.html<br />
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== Grand Challenges in Transportation and Transit Systems ==<br />
March 8, 7:43 PM<br><br />
From Front. Built Environ., 24 February 2016 | <br><br />
Sakdirat Kaewunruen, Joseph M. Sussman and Akira Matsumoto<br><br />
(Translated by -)<br><br />
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''Transportation and transit systems draw upon broad spectra of research fields due to the diversity and interconnectivity of transport modes, including road, rail, aviation, pipeline, maritime, or even aerospace. These systems have evolved over centuries to be considerably more efficient and environment-friendly for a wide range of customers. The fundamental principle “safety first” is still the key priority in most research today. However, thanks to extensive interface with various customers; research and innovation in practices have shifted from optimizing functional purposes and targets through each stage of life cycle toward modernization, reliability, resilience, and better quality of life. These initiatives additionally coincide with the grand challenges for engineering proposed by the National Academy of Engineering and the United Nations’ Millennium Development Goals''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.3389/fbuil.2016.00004<br />
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== Rhetoric of Effortlessness in Science ==<br />
March 10, 7:01 PM<br><br />
From Science March-April 2016 Volume: 24, Number: 2 March-April 2016: 145-166.<br><br />
By James W. McAllister<br><br />
(Translated by -)<br><br />
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''Scientists use several rhetorical strategies to heighten the objectivity and credibility of their findings. Examples are the rhetoric of effort, which involves emphasizing the amount of effort expended in research, and the rhetoric of self-effacement, which involves suggesting that the facts have manifested themselves without input from the researcher. In this article, I present a further, hitherto unrecognized rhetorical strategy that scientists use for the same aims: the rhetoric of effortlessness, which consists in conveying the impression that establishing a result has cost the investigator little effort. This rhetorical strategy heightens the credibility of individual scientific findings, raises the reputation of individual scientists, and propagates an attractive view of science as a whole. I outline the epistemology underpinning the rhetoric of effortlessness and give examples of its use in modern science.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1162/POSC_a_00198<br />
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== Hoaxy: A Platform for Tracking Online Misinformation ==<br />
March 10, 9:31 PM<br><br />
From arxiv.org<br><br />
By Chengcheng Shao, Giovanni Luca Ciampaglia, Alessandro Flammini, Filippo Menczer<br><br />
(Translated by -)<br><br />
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''Massive amounts of misinformation have been observed to spread in uncontrolled fashion across social media. Examples include rumors, hoaxes, fake news, and conspiracy theories. At the same time, several journalistic organizations devote significant efforts to high-quality fact checking of online claims. The resulting information cascades contain instances of both accurate and inaccurate information, unfold over multiple time scales, and often reach audiences of considerable size. All these factors pose challenges for the study of the social dynamics of online news sharing. Here we introduce Hoaxy, a platform for the collection, detection, and analysis of online misinformation and its related fact-checking efforts. We discuss the design of the platform and present a preliminary analysis of a sample of public tweets containing both fake news and fact checking. We find that, in the aggregate, the sharing of fact-checking content typically lags that of misinformation by 10--20 hours. Moreover, fake news are dominated by very active users, while fact checking is a more grass-roots activity. With the increasing risks connected to massive online misinformation, social news observatories have the potential to help researchers, journalists, and the general public understand the dynamics of real and fake news sharing.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.01511<br />
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== Statisticians issue warning over misuse of P values ==<br />
March March 11, 4:29 PM<br><br />
From www.nature.com<br><br />
By <br><br />
(Translated by -)<br><br />
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''Misuse of the P value — a common test for judging the strength of scientific evidence — is contributing to the number of research findings that cannot be reproduced, the American Statistical Association (ASA) warns in a statement released today. The group has taken the unusual step of issuing principles to guide use of the P value, which it says cannot determine whether a hypothesis is true or whether results are important.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://www.nature.com/news/statisticians-issue-warning-over-misuse-of-p-values-1.19503<br />
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== A bacterium that degrades and assimilates poly(ethylene terephthalate) ==<br />
March 11, 6:47 PM<br><br />
From Science 11 Mar 2016: Vol. 351, Issue 6278, pp. 1196-1199<br><br />
By Shosuke Yoshida, et al.<br><br />
(Translated by -)<br><br />
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''Poly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source. When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1126/science.aad6359<br />
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== Sensitivity of global terrestrial ecosystems to climate variability ==<br />
March 12, 4:39 PM<br><br />
From Nature 531, 229–232 (10 March 2016) <br><br />
By Shosuke Yoshida, et al.<br><br />
(Translated by -)<br><br />
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''Using satellite data and a novel analytical approach, a new index of the sensitivity of vegetation to climate variability is developed, revealing areas of high sensitivity that include tundra, boreal forest, tropical forest and temperate grasslands.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/nature16986<br />
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== Social Evolution Selects for Redundancy in Bacterial Quorum Sensing ==<br />
March 12, 5:31 PM<br><br />
From Social Evolution Selects for Redundancy in Bacterial Quorum Sensing. PLoS Biol 14(2): e1002386<br><br />
By Even-Tov E, Omer Bendori S, Valastyan J, Ke X, Pollak S, Bareia T, et al.<br><br />
(Translated by -)<br><br />
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''Quorum sensing is a mechanism through which bacteria communicate by producing, releasing, and detecting signal molecules encoding information about cell population density. Quorum sensing allows bacteria to synchronize their behaviors and act as collectives. Often, quorum sensing controls cooperative behaviors that benefit the entire community, such as the production and secretion of costly metabolites. Some bacteria release multiple signal molecules which, once detected, funnel information into the same cellular response. Thus, the benefit of using multiple rather than a single signal is mysterious since the signals seem redundant. Here, we combine modeling and experiments to show that the evolutionary accumulation of multiple quorum-sensing systems can be attributed to social exploitation and kin recognition. When in low abundance, a strain that has acquired an additional quorum-sensing system can avoid cooperating and can exploit its ancestor strain, which contains one less quorum-sensing system. The cheater containing the additional system returns to a cooperative behavior when it is abundant. We also identify the molecular mechanisms necessary for the acquisition of an additional signaling system. Our work demonstrates that increased complexity in bacterial social signaling circuits can evolve without providing an adaptive advantage in a clonal population.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1371/journal.pbio.1002386<br />
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== Major transitions in evolution and in technology: What they have in common and where they differ ==<br />
March 12, 7:05 PM<br><br />
From Complexity<br><br />
By Peter Schuster<br><br />
(Translated by -)<br><br />
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''What have technological and biological evolution in common? One feature has been mentioned just above: Technologies and the professions related to them have finite lifetimes like biological species. Efficiency and other economic criteria are crucial for the survival of technologies and play the same role as fitness does in biological evolution. Technologies form complex networks of mutual dependences just as the different species do in the food webs of ecosystems. One less obvious feature is the tinkering principle. Innovation builds upon already existing technologies and only rarely—in exceptional cases—starts from scratch. One of these exceptions, perhaps, was the introduction of electricity into society. Pre-human nature is an obligatory tinkerer and the tinkering principle was indeed formulated first in the context of biological evolution: Nature does not design with the eyes of an engineer, she works like a tinkerer. Biological evolution can only make use of entities that are already present in the population. Biological evolution does never start from scratch but existing functions are used in different combinations and in a different context. Common to technology and biological evolution is an optimization principle that concerns economic efficiency in the former and fitness in the sense of the number of progeny in the latter case: In case a technology produces the same goods more expensively it will run out of business as a variant within a population does when it has less offspring.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1002/cplx.21773<br />
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== The Enlightenment is Dead, Long Live the Entanglement ==<br />
March 14 8:38 PM<br><br />
From Journal of Design and Science<br><br />
By Danny Hillis<br><br />
(Translated by -)<br><br />
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''We humans are changing. We have become so intertwined with what we have created that we are no longer separate from it. We have outgrown the distinction between the natural and the artificial. We are what we make. We are our thoughts, whether they are created by our neurons, by our electronically augmented minds, by our technologically mediated social interactions, or by our machines themselves. We are our bodies, whether they are born in womb or test tube, our genes inherited or designed, organs augmented, repaired, transplanted, or manufactured. Our prosthetic enhancements are as simple as contact lenses and tattoos and as complex as robotic limbs and search engines. They are both functional and aesthetic. We are our perceptions, whether they are through our eyes and ears or our sensory-fused hyper-spectral sensors, processed as much by computers as by our own cortex. We are our institutions, cooperating super-organisms, entangled amalgams of people and machines with super-human intelligence, processing, sensing, deciding, acting. Our home planet is inhabited by both engineered organisms and evolved machines. Our very atmosphere is the emergent creation of forests, farms and factories. Empowered by the tools of the Enlightenment, connected by networked flows of freight and fuel and finance, by information and ideas, we are becoming something new. We are at the dawn of the Age of Entanglement.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://jods.mitpress.mit.edu/pub/enlightenment-to-entanglement<br />
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== Epistemological Odyssey: Introduction to Special Issue on the Diversity of Enactivism and Neurophenomenology ==<br />
March 15, 5:06 PM<br><br />
From Constructuvist Foundations Volume 11 · Number 2 · Pages 189–204<br><br />
By Sebastjan Vörös, Tom Froese & Alexander Riegler<br><br />
(Translated by -)<br><br />
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''Context: In the past two decades, the so-called 4E approaches to the mind and cognition have been rapidly gaining in recognition and have become an integral part of various disciplines. Problem: Recently, however, questions have been raised as to whether, and to what degree, these different approaches actually cohere with one another. Specifically, it seems that many of them endorse mutually incompatible, perhaps even contradictory, epistemological and metaphysical presuppositions. Method: By retracing the roots of an alternative conception of mind and cognition, as propounded by Varela, Thompson & Rosch, we provide an outline of the original philosophical framework of enactivism and neurophenomenology. We focus on its three central tenets - reflexivity, subject-world co-determination, and the construal of cognition as situated, skillful and embodied action - and show how they collectively add up to a radical change in attitude towards the age-old philosophical dilemmas. Results: We show how contemporary enactivist and embodied approaches relate to the original Varelian conception, and argue that many of them, despite frequent claims to the contrary, adopt significantly less radical philosophical positions. Further, we provide some tentative suggestions as to why this dilution of the original impetus might have occurred, paying special attention to the deep-rooted disparities that span the field. Implications: It is argued that more attention should be paid to epistemological and metaphysical tenets of different proposals within the 4E movement in general and enactivism in particular. Additionally, in emphasizing the inescapable multilayeredness and contextuality of scientific knowledge, enactivism and neurophenomenology accord with pluralist accounts of science and might provide important contributions to contemporary debates in the field. Constructivist content: The epistemological odyssey, construed as a journey to find a middle way between realism and idealism, is a central tenet of anti-representationalist, non-dualist constructivist approaches aimed at avoiding age-old philosophical traps.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://www.univie.ac.at/constructivism/journal/11/2/189.editorial<br />
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== Improving Urban Mobility by Understanding its Complexity ==<br />
March 15, 7:12 PM<br><br />
From arxiv.org<br><br />
By Carlos Gershenson<br><br />
(Translated by -)<br><br />
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''Urban mobility systems are composed multiple elements with strong interactions, i.e. their future is co-determined by the state of other elements. Thus, studying components in isolation, i.e. using a reductionist approach, is inappropriate. I propose five recommendations to improve urban mobility based on insights from the scientific study of complex systems: use adaptation over prediction, regulate interactions to avoid friction, use sensors to recover real time information, develop adaptive algorithms to exploit that information, and deploy agents to act on the urban environment.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.04267<br />
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== Design as Participation ==<br />
March 16, 8:40 PM<br><br />
From Journal of Design and Science<br><br />
By Kevin Slavin<br><br />
(Translated by -)<br><br />
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''The hypothesis is that most designers that are deliberately working with complex adaptive systems cannot help but be humbled by them. Maybe those who really design systems-interacting-with-systems approach their relationships to said systems with the daunting complexity of influence, rather than the hubris of definition or control.<br />
The designers of complex adaptive systems are not strictly designing systems themselves. They are hinting those systems towards anticipated outcomes, from an array of existing interrelated systems. These are designers that do not understand themselves to be in the center of the system. Rather, they understand themselves to be participants, shaping the systems that interact with other forces, ideas, events and other designers. This essay is an exploration of what it means to participate.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://jods.mitpress.mit.edu/pub/design-as-participation<br />
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== Discovery of fairy circles in Australia supports self-organization theory ==<br />
March 17, 11:08 AM<br><br />
From www.pnas.org<br><br />
By Stephan Getzin, et al.<br><br />
(Translated by -)<br><br />
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''Pattern-formation theory predicts that vegetation gap patterns, such as the fairy circles of Namibia, emerge through the action of pattern-forming biomass–water feedbacks and that such patterns should be found elsewhere in water-limited systems around the world. We report here the exciting discovery of fairy-circle patterns in the remote outback of Australia. Using fieldwork, remote sensing, spatial pattern analysis, mathematical modeling, and pattern-formation theory we show that the Australian gap patterns share with their Namibian counterparts the same characteristics but are driven by a different biomass–water feedback. These observations are in line with a central universality principle of pattern-formation theory and support the applicability of this theory to wider contexts of spatial self-organization in ecology.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1073/pnas.1522130113<br />
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== Do jobs run in families? ==<br />
March 17, 11:08 AM<br><br />
From research.facebook.com<br><br />
By Ismail Onur Filiz, Lada Adamic<br><br />
(Translated by -)<br><br />
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''How much of our choice of profession depends on who our parents are? Parents pass on their genes, set an example, provide opportunities, and give advice to either aim for or steer clear of their own lines of work. In the end, do their children end up in the same type of job? Do siblings choose the same occupation? And is this more or less true for different professions?''<br />
''To study these questions, we analyzed in aggregate two related sets of de-identified Facebook data: one a sample of siblings' choices of profession, and the other of parent-child choices. The sample included those pairs of individuals in English-speaking locales who specified a sibling or parent-child relationship on Facebook, along with filling in their occupations. The occupations were mapped to major occupation categories 1. The military occupation category is over-represented because it is mapped based on both employer and stated occupation and past military service, whereas other job categories were mapped based on stated occupation only. Since the data excludes those not specifying an occupation on Facebook, it may not be representative of the population overall, but is interesting to study nonetheless.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''https://research.facebook.com/blog/do-jobs-run-in-families-/<br />
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== Revisiting Street Intersections Using Slot-Based Systems ==<br />
March 17, 1:05 PM<br><br />
From Revisiting Street Intersections Using Slot-Based Systems. PLoS ONE 11(3): e0149607. <br><br />
By Tachet R, Santi P, Sobolevsky S, Reyes-Castro LI, Frazzoli E, Helbing D, et al. <br><br />
(Translated by -)<br><br />
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''Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1371/journal.pone.0149607<br />
Complexity Digest's insight:<br />
See Also: http://senseable.mit.edu/light-traffic/<br />
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== Policy:urban physics ==<br />
March 18, 10:10 AM<br><br />
From Nature 531, S64–S66 (17 March 2016)<br><br />
By Kevin Pollock<br><br />
(Translated by -)<br><br />
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''Cities are complex environments. Planning interventions that borrow principles from theoretical physics could help to improve peoples' lives.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/531S64a<br />
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== Living factories of the future ==<br />
March 18, 6:01 PM<br><br />
From Nature 531, 401–403 (17 March 2016) <br><br />
By Michael Eisenstein<br><br />
(Translated by -)<br><br />
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''Scientists are designing cells that can manufacture drugs, food and materials — and even act as diagnostic biosensors. But first they must agree on a set of engineering tools.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/531401a<br />
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== Age of Entanglement ==<br />
March 18, 8:42 PM<br><br />
From jods.mitpress.mit.edu <br><br />
By Neri Oxman<br><br />
(Translated by -)<br><br />
<br />
''This essay proposes a map for four domains of creative exploration—Science, Engineering, Design and Art—in an attempt to represent the antidisciplinary hypothesis: that knowledge can no longer be ascribed to, or produced within, disciplinary boundaries, but is entirely entangled. The goal is to establish a tentative, yet holistic, cartography of the interrelation between these domains, where one realm can incite ®evolution inside another; and where a single individual or project can reside in multiple dominions. Mostly, this is an invitation to question and to amend what is being proposed.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://jods.mitpress.mit.edu/pub/AgeOfEntanglement<br />
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== If the World Began Again, Would Life as We Know It Exist? ==<br />
March 18, 12:13 PM<br><br />
From nautil.us<br><br />
By <br><br />
(Translated by -)<br><br />
<br />
''Experiments in evolution are exploring what would happen if we rewound the tape of life.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://nautil.us/issue/34/adaptation/if-the-world-began-again-would-life-as-we-know-it-exist-rp<br />
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== How Do You Say “Life” in Physics? ==<br />
March 19, 10:29 AM<br><br />
From nautil.us<br><br />
By <br><br />
(Translated by -)<br><br />
<br />
''We think we know life when we see it. Darwin’s theory even explains how one form of life evolves into another. But what is the difference between a robin and a rock, when both obey the same physical laws? In other words, how do you say “life” in physics? Some have argued that the word is untranslatable. But maybe it simply needed the right translator.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://nautil.us/issue/34/adaptation/how-do-you-say-life-in-physics<br />
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== Design and Science ==<br />
March 20, 8:44 PM<br><br />
From jods.mitpress.mit.edu<br><br />
By Joichi Ito<br><br />
(Translated by -)<br><br />
<br />
''For me, antidisciplinary research is akin to mathematician Stanislaw Ulam’s famous observation that the study of nonlinear physics is like the study of “non-elephant animals.” Antidisciplinary is all about the non-elephant animals.I believe that by bringing together design and science we can produce a rigorous but flexible approach that will allow us to explore, understand and contribute to science in an antidisciplinary way.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://jods.mitpress.mit.edu/pub/designandscience<br />
<br><br />
<br />
== Cell Fate Reprogramming by Control of Intracellular Network Dynamics ==<br />
March 22, 6:07 PM<br><br />
From PLoS Comput Biol 11(4): e1004193. <br><br />
By Zañudo JGT, Albert R<br><br />
(Translated by -)<br><br />
<br />
''Practical applications in modern molecular and systems biology such as the search for new therapeutic targets for diseases and stem cell reprogramming have generated a great interest in controlling the internal dynamics of a cell. Here we present a network control approach that integrates the structural and functional information of the network. We show that stabilizing the expression or activity of a few select components can drive the cell towards a desired fate or away from an undesired fate. We demonstrate our method’s effectiveness by applying it to a type of blood cell cancer and to the differentiation of a type of immune cell. Overall, our approach provides new insights into how to control the dynamics of intracellular networks.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://dx.doi.org/10.1371/journal.pcbi.1004193<br />
<br><br />
<br />
== Military Strategy in a Complex World ==<br />
March 23, 12:29 PM<br><br />
From www.necsi.edu<br><br />
By Dominic K. Albino, Katriel Friedman, Yaneer Bar-Yam, William Glenney<br><br />
(Translated by -)<br><br />
<br />
''A strategy is a plan, method, or series of actions for obtaining a specified goal. A military strategy typically employs the threat or use of military force to advance goals in opposition to an adversary, and is called upon where large scale force is viewed as the way to achieve such goals. Strategic thinking is traditionally focused on which part or combination of land, air, and naval forces is most effective. This may be too narrow an approach to accomplishing the ultimate end, which is generally political influence or control—or preventing influence or control by others—and almost never consists of physical destruction itself. In order to broaden the discussion of military strategy, we consider here three distinct effects of inflicting stress on an opponent: a) A fragile system is damaged—possibly catastrophically, b) A robust system is largely unaffected, retaining much or all of its prior strength, c) Some systems actually gain strength, a property which has recently been termed antifragility. Traditional perspectives of military strategy implicitly assume fragility, limiting their validity and resulting in surprise, and assume a specific end state rather than an overall condition of the system as a goal. Robustness and antifragility are relevant both to offense, in attacks against the enemy, and defense, in meeting attacks against one’s own forces. While robustness and antifragility are desirable in friendly systems, an enemy possessing these characteristics undermines the premise that an attack will achieve a desired increase in control. Historical and contemporary examples demonstrate the failure of traditional strategies against antifragile enemies—even devastating damage inflicted upon nations or other organizations did not weaken and defeat them, but rather strengthened them, resulting in their victory. Underlying such successful responses are socio-economic or political strengths. Our discussion is a basis for scientific analysis of the historical and contemporary conditions under which distinct types of strategies will be successful and provides guidance to improved strategic thinking.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://www.necsi.edu/research/military/strategy.html<br />
<br><br />
<br />
== How Diversity Makes Us Smarter ==<br />
March 23, 2:34 PM<br><br />
From www.scientificamerican.com<br><br />
By Katherine W. Phillips<br><br />
(Translated by -)<br><br />
<br />
''Decades of research by organizational scientists, psychologists, sociologists, economists and demographers show that socially diverse groups (that is, those with a diversity of race, ethnicity, gender and sexual orientation) are more innovative than homogeneous groups.It seems obvious that a group of people with diverse individual expertise would be better than a homogeneous group at solving complex, nonroutine problems. It is less obvious that social diversity should work in the same way—yet the science shows that it does.This is not only because people with different backgrounds bring new information. Simply interacting with individuals who are different forces group members to prepare better, to anticipate alternative viewpoints and to expect that reaching consensus will take effort.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://www.scientificamerican.com/article/how-diversity-makes-us-smarter/<br />
<br><br />
<br />
== The impact of social networks on leadership behaviour ==<br />
March 23, 12:37 PM<br><br />
From mio.sagepub.com<br><br />
By <br><br />
(Translated by -)<br><br />
<br />
''Dominant streams in leadership literature conceptualise it either as a role within sociopolitical structure or as a behavioural predisposition of agents. In this article, a number of hypotheses are tested via an empirical case study where interaction and affiliation networks across multiple decision experiments are coupled with attribute and psychometric data of the actors. Findings suggest that in egalitarian political systems, centrality in social networks is directly associated with political success, while in political systems imbued with power inequalities successful actors are idiocentric brokers. The use of attitudinal micro-surveys, psychometric tests, observation and relational surveys is combined for a comprehensive mapping of group dynamics suited to questions of agency. ''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://mio.sagepub.com/content/9/2059799116630649.full<br />
<br><br />
<br />
== Unveiling causal activity of complex networks ==<br />
March 23, 6:34 PM<br><br />
From arxiv.org<br><br />
By Rashid V. Williams-Garcia, John M. Beggs, Gerardo Ortiz<br><br />
(Translated by -)<br><br />
<br />
''We introduce a novel tool for analyzing complex network dynamics, allowing for cascades of causally-related events, which we call causal webs (c-webs for short), to be separated from other activity. In the context of neural networks, c-webs represent a new, emergent dynamical degree of freedom which highlights the effective network connectivity, in contrast with the oft-used degrees of freedom, neuronal avalanches. By identifying non-causal activity, our method can also be used to characterize dynamical disorder in complex networks. Using this method, we reveal causally-related activity from experimental data with statistics which may support quasicriticality in the brain.''<br />
<br><br>(请在此输入译文)<br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.05659<br />
<br><br />
<br />
==Human judgment vs. theoretical models for the management of ecological resources==<br />
From arxiv.org <br><br />
March 24, 6:39 PM<br><br />
By Matthew Holden, Stephen Ellner<br><br />
(Translated by -)<br><br />
<br />
''Despite major advances in quantitative approaches to natural resource management, there has been resistance to using these tools in the actual practice of managing ecological populations. Given a managed system and a set of assumptions, translated into a model, optimization methods can be used to solve for the most cost effective management actions. However, when the underlying assumptions are not met, such methods can potentially lead to poor decisions. Managers who develop decisions based on past experience and judgment, without the aid of mathematical models, can potentially learn about the system and develop flexible management strategies. However, these strategies are often based on subjective criteria and equally invalid and often unstated assumptions. Given the drawbacks of both methods, it is unclear whether simple quantitative models improve environmental decision making over expert opinion. In this paper, we explore how well students, using their experience and judgment, manage simulated fishery populations in an online computer game and compare their management outcomes to the performance of model-based decisions. We consider harvest decisions generated using four different quantitative models: 1. the model used to produce the simulated population dynamics observed in the game, with all underlying parameter values known [a control], 2. the same model, but with unknown parameter values that must be estimated during the game from observed data, 3. models that are structurally different from those used to simulate the population dynamics and 4. a model that ignores age structure. Humans on average performed much worse than the models in cases 1 - 3. When the models ignored age structure, they generated poorly performing management decisions, but still outperformed students using experience and judgment 66 percent of the time. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.04518<br />
<br />
<br />
==Fetishizing Food in Digital Age: #foodporn Around the World==<br />
<br />
From arxiv.org <br> <br />
March 23, 8:31 PM <br><br />
By Yelena Mejova, Sofiane Abbar, Hamed Haddadi <br><br />
<br />
''What food is so good as to be considered pornographic? Worldwide, the popular #foodporn hashtag has been used to share appetizing pictures of peoples' favorite culinary experiences. But social scientists ask whether #foodporn promotes an unhealthy relationship with food, as pornography would contribute to an unrealistic view of sexuality. In this study, we examine nearly 10 million Instagram posts by 1.7 million users worldwide. An overwhelming (and uniform across the nations) obsession with chocolate and cake shows the domination of sugary dessert over local cuisines. Yet, we find encouraging traits in the association of emotion and health-related topics with #foodporn, suggesting food can serve as motivation for a healthy lifestyle. Social approval also favors the healthy posts, with users posting with healthy hashtags having an average of 1,000 more followers than those with unhealthy ones. Finally, we perform a demographic analysis which shows nation-wide trends of behavior, such as a strong relationship (r=0.51) between the GDP per capita and the attention to healthiness of their favorite food. Our results expose a new facet of food "pornography", revealing potential avenues for utilizing this precarious notion for promoting healthy lifestyles. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:''' http://arxiv.org/abs/1603.00229<br />
<br />
==Homophily, influence and the decay of segregation in self-organizing networks==<br />
From Network Science / Volume 4 / Issue 01 / March 2016, pp 81-116 <br><br />
March 24, 6:56 PM <br><br />
By ADAM DOUGLAS HENRY, DIETER MITSCHE and PAWEŁ PRAŁAT <br><br />
<br />
''We study the persistence of network segregation in networks characterized by the co-evolution of vertex attributes and link structures, in particular where individual vertices form linkages on the basis of similarity with other network vertices (homophily), and where vertex attributes diffuse across linkages, making connected vertices more similar over time (influence). A general mathematical model of these processes is used to examine the relative influence of homophily and influence in the maintenance and decay of network segregation in self-organizing networks. While prior work has shown that homophily is capable of producing strong network segregation when attributes are fixed, we show that adding even minute levels of influence is sufficient to overcome the tendency towards segregation even in the presence of relatively strong homophily processes. This result is proven mathematically for all large networks and illustrated through a series of computational simulations that account for additional network evolution processes. This research contributes to a better theoretical understanding of the conditions under which network segregation and related phenomenon—such as community structure—may emerge, which has implications for the design of interventions that may promote more efficient network structures. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:''' http://dx.doi.org/10.1017/nws.2016.1<br />
<br> <br />
<br />
==Fetishizing Food in Digital Age: #foodporn Around the World==<br />
<br />
From arxiv.org <br><br />
March 23, 8:31 PM <br><br />
By Yelena Mejova, Sofiane Abbar, Hamed Haddadi <br><br />
<br />
<br />
''What food is so good as to be considered pornographic? Worldwide, the popular #foodporn hashtag has been used to share appetizing pictures of peoples' favorite culinary experiences. But social scientists ask whether #foodporn promotes an unhealthy relationship with food, as pornography would contribute to an unrealistic view of sexuality. In this study, we examine nearly 10 million Instagram posts by 1.7 million users worldwide. An overwhelming (and uniform across the nations) obsession with chocolate and cake shows the domination of sugary dessert over local cuisines. Yet, we find encouraging traits in the association of emotion and health-related topics with #foodporn, suggesting food can serve as motivation for a healthy lifestyle. Social approval also favors the healthy posts, with users posting with healthy hashtags having an average of 1,000 more followers than those with unhealthy ones. Finally, we perform a demographic analysis which shows nation-wide trends of behavior, such as a strong relationship (r=0.51) between the GDP per capita and the attention to healthiness of their favorite food. Our results expose a new facet of food "pornography", revealing potential avenues for utilizing this precarious notion for promoting healthy lifestyles. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:http://dx.doi.org/10.1017/nws.2016.1<br />
<br />
<br />
==Selection and influence in cultural dynamics==<br />
From Network Science / Volume 4 / Issue 01 / March 2016, pp 1-27 <br><br />
March 24, 8:58 PM <br><br />
By DAVID KEMPE, JON KLEINBERG, SIGAL OREN and ALEKSANDRS SLIVKINS <br><br />
<br />
<br />
''One of the fundamental principles driving diversity or homogeneity in domains such as cultural differentiation, political affiliation, and product adoption is the tension between two forces: influence (the tendency of people to become similar to others they interact with) and selection (the tendency to be affected most by the behavior of others who are already similar). Influence tends to promote homogeneity within a society, while selection frequently causes fragmentation. When both forces act simultaneously, it becomes an interesting question to analyze which societal outcomes should be expected.<br />
To study this issue more formally, we analyze a natural stylized model built upon active lines of work in political opinion formation, cultural diversity, and language evolution. We assume that the population is partitioned into “types” according to some traits (such as language spoken or political affiliation). While all types of people interact with one another, only people with sufficiently similar types can possibly influence one another. The “similarity” is captured by a graph on types in which individuals of the same or adjacent types can influence one another. We achieve an essentially complete characterization of (stable) equilibrium outcomes and prove convergence from all starting states. We also consider generalizations of this model. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://dx.doi.org/10.1017/nws.2015.36<br />
<br />
==Fetishizing Food in Digital Age: #foodporn Around the World==<br />
<br />
From arxiv.org <br><br />
March 23, 8:31 PM <br><br />
By Yelena Mejova, Sofiane Abbar, Hamed Haddadi <br><br />
<br />
<br />
''What food is so good as to be considered pornographic? Worldwide, the popular #foodporn hashtag has been used to share appetizing pictures of peoples' favorite culinary experiences. But social scientists ask whether #foodporn promotes an unhealthy relationship with food, as pornography would contribute to an unrealistic view of sexuality. In this study, we examine nearly 10 million Instagram posts by 1.7 million users worldwide. An overwhelming (and uniform across the nations) obsession with chocolate and cake shows the domination of sugary dessert over local cuisines. Yet, we find encouraging traits in the association of emotion and health-related topics with #foodporn, suggesting food can serve as motivation for a healthy lifestyle. Social approval also favors the healthy posts, with users posting with healthy hashtags having an average of 1,000 more followers than those with unhealthy ones. Finally, we perform a demographic analysis which shows nation-wide trends of behavior, such as a strong relationship (r=0.51) between the GDP per capita and the attention to healthiness of their favorite food. Our results expose a new facet of food "pornography", revealing potential avenues for utilizing this precarious notion for promoting healthy lifestyles. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:''' http://dx.doi.org/10.1017/nws.2015.36<br />
<br />
<br />
==The classical origin of modern mathematics==<br />
From arxiv.org <br><br />
March 25, 6:36 PM <br><br />
By Floriana Gargiulo, Auguste Caen, Renaud Lambiotte, Timoteo Carletti <br><br />
<br />
''The aim of this paper is to study the historical evolution of mathematical thinking and its spatial spreading. To do so, we have collected and integrated data from different online academic datasets. In its final stage, the database includes a large number (N~200K) of advisor-student relationships, with affiliations and keywords on their research topic, over several centuries, from the 14th century until today. We focus on two different topics, the evolving importance of countries and of the research disciplines over time. Moreover we study the database at three levels, its global statistics, the mesoscale networks connecting countries and disciplines, and the genealogical level. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.06371<br />
<br />
<br />
==Special Operations Forces==<br />
<br />
From arXiv:1602.05474v2 (February 18, 2016). <br><br />
March 25, 12:30 PM <br><br />
By Joseph Norman, Yaneer Bar-Yam <br><br />
<br />
''The use of special operations forces (SOF) in war fighting and peace keeping efforts has increased dramatically in recent decades. A scientific understanding of the reason for this increase would provide guidance as to the contexts in which SOF can be used to their best effect. Ashby's law of requisite variety provides a scientific framework for understanding and analyzing a system's ability to survive and prosper in the face of environmental challenges. We have developed a generalization of this law to extend the analysis to systems that must respond to disturbances at multiple scales. This analysis identifies a necessary tradeoff between scale and complexity in a multiscale control system. As with Ashby's law, the framework applies to the characterization of successful biological and social systems in the context of complex environmental challenges. Here we apply this multiscale framework to provide a control theoretic understanding of the historical and increasing need for SOF, as well as conventional military forces. We propose that the essential role distinction is in the separation between high complexity fine scale challenges as opposed to large scale challenges. This leads to a correspondence between the role SOF can best serve and that of the immune system in complex organisms--namely, the ability to respond to fine-grained, high-complexity disruptors and preserve tissue health. Much like a multicellular organism, human civilization is composed of a set of distinct and heterogeneous social tissues. Responding to disruption and restoring health in a system with highly diverse local social conditions is an essentially complex task. SOF have the potential to mitigate against harm without disrupting normal social tissue behavior. This analysis suggests how SOF might be leveraged to support global stability and mitigate against cascading crises. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://www.necsi.edu/research/military/sof.html<br />
<br />
==Corruption corrupts==<br />
From Nature 531, 456–457 (24 March 2016) <br> <br />
March 26, 7:00 AM <br><br />
By Shaul Shalvi <br><br />
<br />
''A cross-cultural experiment involving thousands of people worldwide shows that the prevalence of rule violations in a society, such as tax evasion and fraudulent politics, is detrimental to individuals' intrinsic honesty. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/nature17307<br />
<br />
==Design and synthesis of a minimal bacterial genome==<br />
From Science 25 Mar 2016:Vol. 351, Issue 6280 <br><br />
March 27, 12:24 PM <br><br />
By Clyde A. Hutchison III, et al. <br><br />
<br />
''The minimal cell concept appears simple at first glance but becomes more complex upon close inspection. In addition to essential and nonessential genes, there are many quasi-essential genes, which are not absolutely critical for viability but are nevertheless required for robust growth. Consequently, during the process of genome minimization, there is a trade-off between genome size and growth rate. JCVI-syn3.0 is a working approximation of a minimal cellular genome, a compromise between small genome size and a workable growth rate for an experimental organism. It retains almost all the genes that are involved in the synthesis and processing of macromolecules. Unexpectedly, it also contains 149 genes with unknown biological functions, suggesting the presence of undiscovered functions that are essential for life. JCVI-syn3.0 is a versatile platform for investigating the core functions of life and for exploring whole-genome design. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''DOI: 10.1126/science.aad6253<br />
<br />
<br />
==Analysis and valuation of the health and climate change cobenefits of dietary change==<br />
From www.pnas.org <br> <br />
March 28, 8:06 PM <br><br />
By Marco Springmann, H. Charles J. Godfray, Mike Rayner, and Peter Scarborough <br><br />
<br />
''The food system is responsible for more than a quarter of all greenhouse gas emissions while unhealthy diets and high body weight are among the greatest contributors to premature mortality. Our study provides a comparative analysis of the health and climate change benefits of global dietary changes for all major world regions. We project that health and climate change benefits will both be greater the lower the fraction of animal-sourced foods in our diets. Three quarters of all benefits occur in developing countries although the per capita impacts of dietary change would be greatest in developed countries. The monetized value of health improvements could be comparable with, and possibly larger than, the environmental benefits of the avoided damages from climate change. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://dx.doi.org/ 10.1073/pnas.1523119113<br />
<br />
==The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics==<br />
From Scientific Reports 6, Article number: 23644 (2016) <br><br />
March 29, 5:52 PM <br><br />
By Ugur Tirnakli & Ernesto P. Borges <br><br />
<br />
<br />
''As well known, Boltzmann-Gibbs statistics is the correct way of thermostatistically approaching ergodic systems. On the other hand, nontrivial ergodicity breakdown and strong correlations typically drag the system into out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide class of such systems, it has been shown in recent years that the correct approach is to use Tsallis statistics instead. Here we show how the dynamics of the paradigmatic conservative (area-preserving) stan-dard map exhibits, in an exceptionally clear manner, the crossing from one statistics to the other. Our results unambiguously illustrate the domains of validity of both Boltzmann-Gibbs and Tsallis statistical distributions. Since various important physical systems from particle confinement in magnetic traps to autoionization of molecular Rydberg states, through particle dynamics in accelerators and comet dynamics, can be reduced to the standard map, our results are expected to enlighten and enable an improved interpretation of diverse experimental and observational results. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://dx.doi.org/10.1038/srep23644<br><br><br />
<br />
==Heterogeneity of Global and Local Connectivity in Spatial Network Structures of World Migration==<br />
From arxiv.org <br><br />
March 31, 3:04 PM <br><br />
By Valentin Danchev, Mason A. Porter <br><br />
<br />
<br />
''We examine world migration as a social-spatial network of countries connected via movements of people. We assess how multilateral migratory relationships at global, regional, and local scales coexist ("glocalization"), divide ("polarization"), or form an interconnected global system ("globalization"). To do this, we decompose the world migration network (WMN) into communities---sets of countries with denser than expected migration connections---and characterize their pattern of local (i.e., intracommunity) and global (i.e., intercommunity) connectivity. We distinguish community signatures---"cave", "biregional", and "bridging"---with distinct migration patterns, spatial network structures, temporal dynamics, and underlying antecedents. Cave communities are tightly-knit, enduring structures that tend to channel local migration between contiguous countries; biregional communities are likely to merge migration between two distinct geographic regions (e.g., North Africa and Europe); and bridging communities have hub-and-spoke structures that tend to emerge dynamically from globe-spanning movements. We find that world migration is neither globally interconnected nor reproduces the geographic boundaries as drawn on a world map but involves a heterogeneous interplay of global and local tendencies in different network regions. We discuss the implications of our results for the understating of variability in today's transnational mobility patterns and migration opportunities across the globe. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.09313<br />
<br />
==Dynamics of a population of oscillatory and excitable elements==<br />
From arxiv.org <br><br />
March 31, 4:30 PM <br><br />
By Kevin P. O'Keeffe, Steven H. Strogatz <br><br />
<br />
<br />
''We analyze a variant of a model proposed by Kuramoto, Shinomoto, and Sakaguchi for a large population of coupled oscillatory and excitable elements. Using the Ott-Antonsen ansatz, we reduce the behavior of the population to a two-dimensional dynamical system with three parameters. We present the stability diagram and calculate several of its bifurcation curves analytically, for both excitatory and inhibitory coupling. Our main result is that when the coupling function is broad, the system can display bistability between steady states of constant high and low activity, whereas when the coupling function is narrow and inhibitory, one of the states in the bistable regime can show persistent pulsations in activity. ''<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.08803<br />
<br />
==The Death and Life of Great Italian Cities: A Mobile Phone Data Perspective==<br />
From arxiv.org <br><br />
March 31, 8:36 PM <br><br />
By Marco De Nadai, Jacopo Staiano, Roberto Larcher, Nicu Sebe, Daniele Quercia, Bruno Lepri <br><br />
<br />
<br />
''The Death and Life of Great American Cities was written in 1961 and is now one of the most influential book in city planning. In it, Jane Jacobs proposed four conditions that promote life in a city. However, these conditions have not been empirically tested until recently. This is mainly because it is hard to collect data about "city life". The city of Seoul recently collected pedestrian activity through surveys at an unprecedented scale, with an effort spanning more than a decade, allowing researchers to conduct the first study successfully testing Jacobs's conditions. In this paper, we identify a valuable alternative to the lengthy and costly collection of activity survey data: mobile phone data. We extract human activity from such data, collect land use and socio-demographic information from the Italian Census and Open Street Map, and test the four conditions in six Italian cities. Although these cities are very different from the places for which Jacobs's conditions were spelled out (i.e., great American cities) and from the places in which they were recently tested (i.e., the Asian city of Seoul), we find those conditions to be indeed associated with urban life in Italy as well. Our methodology promises to have a great impact on urban studies, not least because, if replicated, it will make it possible to test Jacobs's theories at scale. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.04012<br />
<br />
==Phase transitions and hysteresis of cooperative contagion processes ==<br />
From arxiv.org<br><br />
March 31, 6:33 PM <br><br />
By Li Chen, Fakhteh Ghanbarnejad, Dirk Brockmann<br><br />
''We investigate the effects of cooperation between two interacting infectious diseases that spread and stabilize in a host population. We propose a model in which individuals that are infected with one disease are more likely to acquire the second disease, both diseases following the susceptible-infected-susceptible reaction scheme. We analyze cooperative coinfection in stochastic network models as well as the idealized, well-mixed mean field system and show that cooperative mechanisms dramatically change the nature of phase transitions compared to single disease dynamics. We show that, generically, cooperative coinfection exhibits discontinuous transitions from the disease free to high prevalence state when a critical transmission rate is crossed. Furthermore, cooperative coinfection exhibits two distinct critical points, one for outbreaks the second one for eradication that can be substantially lower. This implies that cooperative coinfection exhibits hysteresis in its response to changing effective transmission rates or equivalently the basic reproduction number. We compute these critical parameters as a function of a cooperativity coefficient in the well-mixed mean field system. We finally investigate a spatially extended version of the model and show that cooperative interactions between diseases change the general wave propagation properties of conventional spreading phenomena of single diseases. The presented work may serve as a starting and reference point for a more comprehensive understanding of interacting diseases that spread in populations. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://arxiv.org/abs/1603.09082<br />
<br />
==Can a video game company tame toxic behaviour? ==<br />
From www.nature.com <br><br />
March 31, 10:11 PM <br><br />
By <br><br />
''Scientists are helping to stop antisocial behaviour in the world's most popular online game. The next stop could be a kinder Internet. ''<br />
<br />
<br><br><nowiki> (请在此输入译文) </nowiki><br><br><br />
'''原文链接:'''http://www.nature.com/news/can-a-video-game-company-tame-toxic-behaviour-1.19647<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%BA%94%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.2%E6%9C%88%E6%96%87%E7%AB%A0)&diff=15175
复杂文摘翻译第五期-(摘自Complex Digest 2016.2月文章)
2020-10-14T14:12:39Z
<p>Thingamabob:创建页面,内容为“复杂文摘翻译第五期-(摘自Complex Digest 2016.2月文章) == Scaling and universality in urban economic diversification == ''Network Science / Volume 4…”</p>
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<div>复杂文摘翻译第五期-(摘自Complex Digest 2016.2月文章)<br />
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== Scaling and universality in urban economic diversification ==<br />
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''Network Science / Volume 4 / Issue 02 / June 2016, pp 141-163''<br />
''DOI: 10.1098/rsif.2015.0937''<br />
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''by Hyejin Youn, Luís M. A. Bettencourt, José Lobo, Deborah Strumsky, Horacio Samaniego, Geoffrey B. West''<br />
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''Understanding cities is central to addressing major global challenges from climate change to economic resilience. Although increasingly perceived as fundamental socio-economic units, the detailed fabric of urban economic activities is only recently accessible to comprehensive analyses with the availability of large datasets. Here, we study abundances of business categories across US metropolitan statistical areas, and provide a framework for measuring the intrinsic diversity of economic activities that transcends scales of the classification scheme. A universal structure common to all cities is revealed, manifesting self-similarity in internal economic structure as well as aggregated metrics (GDP, patents, crime). We present a simple mathematical derivation of the universality, and provide a model, together with its economic implications of open-ended diversity created by urbanization, for understanding the observed empirical distribution. Given the universal distribution, scaling analyses for individual business categories enable us to determine their relative abundances as a function of city size. These results shed light on the processes of economic differentiation with scale, suggesting a general structure for the growth of national economies as integrated urban systems.''<br />
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'''原文链接:'''http://rsif.royalsocietypublishing.org/content/13/114/20150937<br />
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== Large-scale signatures of unconsciousness are consistent with a departure from critical dynamics ==<br />
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''Journal of The Royal Society Interface January 2016 Volume 13, issue 114''<br />
''DOI: 10.1098/rsif.2015.1027''<br />
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''by Enzo Tagliazucchi, Dante R. Chialvo, Michael Siniatchkin, Enrico Amico, Jean-Francois Brichant, Vincent Bonhomme, Quentin Noirhomme, Helmut Laufs, Steven Laureys''<br />
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''Loss of cortical integration and changes in the dynamics of electrophysiological brain signals characterize the transition from wakefulness towards unconsciousness. In this study, we arrive at a basic model explaining these observations based on the theory of phase transitions in complex systems. We studied the link between spatial and temporal correlations of large-scale brain activity recorded with functional magnetic resonance imaging during wakefulness, propofol-induced sedation and loss of consciousness and during the subsequent recovery. We observed that during unconsciousness activity in frontothalamic regions exhibited a reduction of long-range temporal correlations and a departure of functional connectivity from anatomical constraints. A model of a system exhibiting a phase transition reproduced our findings, as well as the diminished sensitivity of the cortex to external perturbations during unconsciousness. This framework unifies different observations about brain activity during unconsciousness and predicts that the principles we identified are universal and independent from its causes.''<br />
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'''原文链接:'''http://rsif.royalsocietypublishing.org/content/13/114/20151027<br />
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== Gender, Productivity, and Prestige in Computer Science Faculty Hiring Networks ==<br />
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''Proc. 2016 World Wide Web Conference (WWW), 1169-1179 (2016)''<br />
''arXiv:1602.00795v1 [cs.SI] (Submitted on 2 Feb 2016)''<br />
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''by Samuel F. Way, Daniel B. Larremore, Aaron Clauset''<br />
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''Women are dramatically underrepresented in computer science at all levels in academia and account for just 15% of tenure-track faculty. Understanding the causes of this gender imbalance would inform both policies intended to rectify it and employment decisions by departments and individuals. Progress in this direction, however, is complicated by the complexity and decentralized nature of faculty hiring and the non-independence of hires. Using comprehensive data on both hiring outcomes and scholarly productivity for 2659 tenure-track faculty across 205 Ph.D.-granting departments in North America, we investigate the multi-dimensional nature of gender inequality in computer science faculty hiring through a network model of the hiring process. Overall, we find that hiring outcomes are most directly affected by (i) the relative prestige between hiring and placing institutions and (ii) the scholarly productivity of the candidates. After including these, and other features, the addition of gender did not significantly reduce modeling error. However, gender differences do exist, e.g., in scholarly productivity, postdoctoral training rates, and in career movements up the rankings of universities, suggesting that the effects of gender are indirectly incorporated into hiring decisions through gender's covariates. Furthermore, we find evidence that more highly ranked departments recruit female faculty at higher than expected rates, which appears to inhibit similar efforts by lower ranked departments. These findings illustrate the subtle nature of gender inequality in faculty hiring networks and provide new insights to the underrepresentation of women in computer science.''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.00795<br />
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== Critical fluctuations in proteins native states ==<br />
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''arXiv:1601.03420v1 [physics.bio-ph] (Submitted on 13 Jan 2016)''<br />
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''by Qian-Yuan Tang, Yang-Yang Zhang, Jun Wang, Wei Wang, Dante R. Chialvo''<br />
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''We study a large data set of protein structure ensembles of very diverse sizes determined by nuclear magnetic resonance. By examining the distance-dependent correlations in the displacement of residues pairs and conducting finite size scaling analysis it was found that the correlations and susceptibility behave as in systems near a critical point implying that, at the native state, the motion of each amino acid residue is felt by every other residue up to the size of the protein molecule. Furthermore certain protein's shapes corresponding to maximum susceptibility were found to be more probable than others. Overall the results suggest that the protein's native state is critical, implying that despite being posed near the minimum of the energy landscape, they still preserve their dynamic flexibility.''<br />
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这篇文章是我写的文章,如有必要,到时候我自己来翻译。(by @傅渥成)<br />
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'''原文链接:'''http://arxiv.org/abs/1601.03420<br />
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== A Biologically Inspired Model of Distributed Online Communication Supporting Efficient Search and Diffusion of Innovation ==<br />
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''Interdisciplinary Description of Complex Systems 14(1), 10-22, 2016''<br />
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''by Soumya Banerjee''<br />
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''We inhabit a world that is not only “small” but supports efficient decentralized search – an individual using local information can establish a line of communication with another completely unknown individual. Here we augment a hierarchical social network model with communication between and within communities. We argue that organization into communities would decrease overall decentralized search times. We take inspiration from the biological immune system which organizes search for pathogens in a hybrid modular strategy. <br />
Our strategy has relevance in search for rare amounts of information in online social networks and could have implications for massively distributed search challenges. Our work also has implications for design of efficient online networks that could have an impact on networks of human collaboration, scientific collaboration and networks used in targeted manhunts. Real world systems, like online social networks, have high associated delays for long-distance links, since they are built on top of physical networks. Such systems have been shown to densify i.e. the average number of neighbours that an individual has increases with time. Hence such networks will have a communication cost due to space and the requirement of building and maintaining and increasing number of connections. We have incorporated such a non-spatial cost to communication in order to introduce the realism of individuals communicating within communities, which we call participation cost. <br />
We introduce the notion of a community size that increases with the size of the system, which is shown to reduce the time to search for information in networks. Our final strategy balances search times and participation costs and is shown to decrease time to find information in decentralized search in online social networks. Our strategy also balances strong-ties (within communities) and weak-ties over long distances (between communities that bring in diverse ideas) and may ultimately lead to more productive and innovative networks of human communication and enterprise. We hope that this work will lay the foundation for strategies aimed at producing global scale human interaction networks that are sustainable and lead to a more networked, diverse and prosperous society.''<br />
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'''原文链接:'''https://ideas.repec.org/a/zna/indecs/v13y2016i4p10-22.html<br />
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== Coupling News Sentiment with Web Browsing Data Improves Prediction of Intra-Day Price Dynamics ==<br />
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''PLoS ONE 11(1): e0146576.''<br />
''DOI: 10.1371/journal.pone.0146576''<br />
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''by Gabriele Ranco , Ilaria Bordino, Giacomo Bormetti, Guido Caldarelli, Fabrizio Lillo, Michele Treccani''<br />
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''The new digital revolution of big data is deeply changing our capability of understanding society and forecasting the outcome of many social and economic systems. Unfortunately, information can be very heterogeneous in the importance, relevance, and surprise it conveys, affecting severely the predictive power of semantic and statistical methods. Here we show that the aggregation of web users’ behavior can be elicited to overcome this problem in a hard to predict complex system, namely the financial market. Specifically, our in-sample analysis shows that the combined use of sentiment analysis of news and browsing activity of users of Yahoo! Finance greatly helps forecasting intra-day and daily price changes of a set of 100 highly capitalized US stocks traded in the period 2012–2013. Sentiment analysis or browsing activity when taken alone have very small or no predictive power. Conversely, when considering a news signal where in a given time interval we compute the average sentiment of the clicked news, weighted by the number of clicks, we show that for nearly 50% of the companies such signal Granger-causes hourly price returns. Our result indicates a “wisdom-of-the-crowd” effect that allows to exploit users’ activity to identify and weigh properly the relevant and surprising news, enhancing considerably the forecasting power of the news sentiment.''<br />
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'''原文链接:'''http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146576<br />
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== Crucial steps to life: From chemical reactions to code using agents ==<br />
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''Biosystems Volume 140, February 2016, Pages 49–57''<br />
''DOI: 10.1016/j.biosystems.2015.12.007''<br />
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''by Guenther Witzany''<br />
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''The concepts of the origin of the genetic code and the definitions of life changed dramatically after the RNA world hypothesis. Main narratives in molecular biology and genetics such as the “central dogma,” “one gene one protein” and “non-coding DNA is junk” were falsified meanwhile. RNA moved from the transition intermediate molecule into centre stage. Additionally the abundance of empirical data concerning non-random genetic change operators such as the variety of mobile genetic elements, persistent viruses and defectives do not fit with the dominant narrative of error replication events (mutations) as being the main driving forces creating genetic novelty and diversity. The reductionistic and mechanistic views on physico-chemical properties of the genetic code are no longer convincing as appropriate descriptions of the abundance of non-random genetic content operators which are active in natural genetic engineering and natural genome editing.''<br />
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'''原文链接:'''http://www.sciencedirect.com/science/article/pii/S0303264715002063<br />
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== Google AI algorithm masters ancient game of Go ==<br />
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''Nature 529, 445–446 (28 January 2016) ''<br />
''DOI: 10.1038/529445a''<br />
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''by Reginald Smith''<br />
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''A computer has beaten a human professional for the first time at Go — an ancient board game that has long been viewed as one of the greatest challenges for artificial intelligence (AI).<br />
The best human players of chess, draughts and backgammon have all been outplayed by computers. But a hefty handicap was needed for computers to win at Go. Now Google’s London-based AI company, DeepMind, claims that its machine has mastered the game.''<br />
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'''原文链接:'''http://www.nature.com/news/google-ai-algorithm-masters-ancient-game-of-go-1.19234<br />
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== Innovation diffusion on time-varying activity driven networks ==<br />
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''The European Physical Journal B, 2016, Volume 89, Number 1, Page 1''<br />
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''by Alessandro Rizzo, Maurizio Porfiri''<br />
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''Since its introduction in the 1960s, the theory of innovation diffusion has contributed to the advancement of several research fields, such as marketing management and consumer behavior. The 1969 seminal paper by Bass [F.M. Bass, Manag. Sci. 15, 215 (1969)] introduced a model of product growth for consumer durables, which has been extensively used to predict innovation diffusion across a range of applications. Here, we propose a novel approach to study innovation diffusion, where interactions among individuals are mediated by the dynamics of a time-varying network. Our approach is based on the Bass’ model, and overcomes key limitations of previous studies, which assumed timescale separation between the individual dynamics and the evolution of the connectivity patterns. Thus, we do not hypothesize homogeneous mixing among individuals or the existence of a fixed interaction network. We formulate our approach in the framework of activity driven networks to enable the analysis of the concurrent evolution of the interaction and individual dynamics. Numerical simulations offer a systematic analysis of the model behavior and highlight the role of individual activity on market penetration when targeted advertisement campaigns are designed, or a competition between two different products takes place.''<br />
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'''原文链接:'''http://link.springer.com/article/10.1140/epjb/e2015-60933-3?wt_mc=internal.event.1.SEM.ArticleAuthorIncrementalIssue<br />
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== Disentangling the Effects of Social Signals ==<br />
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''Human Computation (2015) 2:2:189-208''<br />
''DOI: 10.15346/hc.v2i2.4''<br />
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''by Tad Hogg, Kristina Lerman''<br />
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''Peer recommendation is a crowdsourcing task that leverages the opinions of many to identify inter- esting content online, such as news, images, or videos. Peer recommendation applications often use social signals, e.g., the number of prior recommendations, to guide people to the more interesting content. How people react to social signals, in combination with content quality and its presenta- tion order, determines the outcomes of peer recommendation, i.e., item popularity. Using Amazon Mechanical Turk, we experimentally measure the effects of social signals in peer recommendation. Specifically, after controlling for variation due to item content and its position, we find that social signals affect item popularity about half as much as position and content do. These effects are somewhat correlated, so social signals exacerbate the “rich get richer” phenomenon, which results in a wider variance of popularity. Further, social signals change individual preferences, creating a “herding” effect that biases people’s judgments about the content. Despite this, we find that social signals improve the efficiency of peer recommendation by reducing the effort devoted to evaluating content while maintaining recommendation quality.''<br />
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'''原文链接:'''http://hcjournal.org/ojs/index.php?journal=jhc&page=article&op=view&path%5B%5D=59&path%5B%5D=59<br />
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== Sentiment analysis and the complex natural language ==<br />
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''Complex Adaptive Systems Modeling 20164:2''<br />
''DOI: 10.1186/s40294-016-0016-9''<br />
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''by Muhammad Taimoor KhanEmail author, Mehr Durrani, Armughan Ali, Irum Inayat, Shehzad Khalid and Kamran Habib Khan''<br />
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''There is huge amount of content produced online by amateur authors, covering a large variety of topics. Sentiment analysis (SA) extracts and aggregates users’ sentiments towards a target entity. Machine learning (ML) techniques are frequently used as the natural language data is in abundance and has definite patterns. ML techniques adapt to domain specific solution at high accuracy depending upon the feature set used. The lexicon-based techniques, using external dictionary, are independent of data to prevent overfitting but they miss context too in specialized domains. Corpus-based statistical techniques require large data to stabilize. Complex network based techniques are highly resourceful, preserving order, proximity, context and relationships. Recent applications developed incorporate the platform specific structural information i.e. meta-data. New sub-domains are introduced as influence analysis, bias analysis, and data leakage analysis. The nature of data is also evolving where transcribed customer-agent phone conversation are also used for sentiment analysis. This paper reviews sentiment analysis techniques and highlight the need to address natural language processing (NLP) specific open challenges. Without resolving the complex NLP challenges, ML techniques cannot make considerable advancements. The open issues and challenges in the area are discussed, stressing on the need of standard datasets and evaluation methodology. It also emphasized on the need of better language models that could capture context and proximity.''<br />
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'''原文链接:'''http://casmodeling.springeropen.com/articles/10.1186/s40294-016-0016-9<br />
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== System under large stress: Prediction and management of catastrophic failures ==<br />
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''Complexity Volume 21, Issue 3, pages 9–12, January/February 2016''<br />
''DOI: 10.1002/cplx.21753''<br />
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''by Alfred Hübler''<br />
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''The tensile strength of a chain is determined by its weakest link. Does this idea apply to more complex systems too? For instance, does the weakest thread of a spider web initiate cascading failure, when a strong wind gust is stretching the web to its limit? What happens to a computer when both the supply voltage and the ambient temperature are more than 20% outside its normal range of operations?<br />
Climate change, an increasingly more densely populated world and the rapid change of technology seem to put more systems under large stress. Engineering sustainable systems with a more favorable response to large stress appears to be an urgent societal need. Emergency evacuations of hospitals after hurricane Katharina and Sandy, and the May 22, 2011 tornado in Joplin illustrate the urgent need for modeling the adaptive capacity of hospitals during an extended loss of infrastructure [1]. Presidential Policy Directive 21 [2] and the U.S. Department of Homeland Security National Infrastructure Protection Plan (NIPP) [3] call for increasing resilience of the nation’s critical infrastructure.''<br />
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'''原文链接:'''http://onlinelibrary.wiley.com/doi/10.1002/cplx.21753/abstract<br />
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== How ecosystems change ==<br />
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''Science 29 Jan 2016:Vol. 351, Issue 6272, pp. 448-449''<br />
''DOI: 10.1126/science.aad6758''<br />
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''by Anne E. Magurran''<br />
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''Human impacts on the planet, including anthropogenic climate change, are reshaping ecosystems in unprecedented ways. To meet the challenge of conserving biodiversity in this rapidly changing world, we must understand how ecological assemblages respond to novel conditions (1). However, species in ecosystems are not fixed entities, even without human-induced change. All ecosystems experience natural turnover in species presence and abundance. Taking account of this baseline turnover in conservation planning could play an important role in protecting biodiversity.''<br />
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'''原文链接:'''http://science.sciencemag.org/content/351/6272/448.full<br />
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== P-values: misunderstood and misused ==<br />
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''Frontiers in Physics: Vidgen B and Yasseri T (2016) P-Values: Misunderstood and Misused. Front. Phys. 4:6''<br />
''DOI: 10.3389/fphy.2016.00006''<br />
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''by Bertie Vidgen, Taha Yasseri''<br />
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''P-values are widely used in both the social and natural sciences to quantify the statistical significance of observed results. The recent surge of big data research has made the p-value an even more popular tool to test the significance of a study. However, substantial literature has been produced critiquing how p-values are used and understood. In this paper we review this recent critical literature, much of which is routed in the life sciences, and consider its implications for social scientific research. We provide a coherent picture of what the main criticisms are, and draw together and disambiguate common themes. In particular, we explain how the False Discovery Rate is calculated, and how this differs from a p-value. We also make explicit the Bayesian nature of many recent criticisms, a dimension that is often underplayed or ignored. We conclude by identifying practical steps to help remediate some of the concerns identified. We recommend that (i) far lower significance levels are used, such as 0.01 or 0.001, and (ii) p-values are interpreted contextually, and situated within both the findings of the individual study and the broader field of inquiry (through, for example, meta-analyses).''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.06805<br />
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== What is Information? ==<br />
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''Philosophical Transaction of the Royal Society A 374 (2016) 20150230''<br />
''DOI: 10.1098/rsta.2015.0230''<br />
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''by Christoph Adami''<br />
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''Information is a precise concept that can be defined mathematically, but its relationship to what we call "knowledge" is not always made clear. Furthermore, the concepts "entropy" and "information", while deeply related, are distinct and must be used with care, something that is not always achieved in the literature. In this elementary introduction, the concepts of entropy and information are laid out one by one, explained intuitively, but defined rigorously. I argue that a proper understanding of information in terms of prediction is key to a number of disciplines beyond engineering, such as physics and biology.''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.06176<br />
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== Introduction to Focus Issue: The 25th Anniversary of Chaos: Perspectives on Nonlinear Science—Past, Present, and Future ==<br />
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''Chaos 25, 097501 (2015)''<br />
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''by Elizabeth Bradley, Adilson E. Motter and Louis M. Pecora''<br />
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''The first issue of Chaos, published in July of 1991, comprised a selection of 14 now-classic papers authored by leading researchers in nonlinear dynamics.1–14 While some of their distinguished authors—including Vladimir Arnold, Boris Chirikov, and George Zaslavsky—are no longer with us, many of the contributors to the first issue remain active in research and some—Irving Epstein and Leon Glass—are in fact authors of papers in this 25th anniversary issue.''<br />
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'''原文链接:'''http://scitation.aip.org/content/aip/journal/chaos/25/9/10.1063/1.4931448?Track=CHAOSJAN2016&dm_i=1XPS,3ZW2T,C9RLUL,EFQPK,1<br />
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== A Non-Newtonian Fluid Robot ==<br />
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''Artificial Life Winter 2016, Vol. 22, No. 1, Pages 1-22''<br />
''DOI: 10.1162/ARTL_a_00194''<br />
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''by Guy Hachmon, et al.''<br />
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''New types of robots inspired by biological principles of assembly, locomotion, and behavior have been recently described. In this work we explored the concept of robots that are based on more fundamental physical phenomena, such as fluid dynamics, and their potential capabilities. We report a robot made entirely of non-Newtonian fluid, driven by shear strains created by spatial patterns of audio waves. We demonstrate various robotic primitives such as locomotion and transport of metallic loads—up to 6-fold heavier than the robot itself—between points on a surface, splitting and merging, shapeshifting, percolation through gratings, and counting to 3. We also utilized interactions between multiple robots carrying chemical loads to drive a bulk chemical synthesis reaction. Free of constraints such as skin or obligatory structural integrity, fluid robots represent a radically different design that could adapt more easily to unfamiliar, hostile, or chaotic environments and carry out tasks that neither living organisms nor conventional machines are capable of.''<br />
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'''原文链接:'''http://www.mitpressjournals.org/doi/abs/10.1162/ARTL_a_00194#.V4sAdpN97_9<br />
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== Scientists make first direct detection of gravitational waves ==<br />
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''MIT News February 11, 2016''<br />
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''by Jennifer Chu''<br />
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''Almost 100 years ago today, Albert Einstein predicted the existence of gravitational waves — ripples in the fabric of space-time that are set off by extremely violent, cosmic cataclysms in the early universe. With his knowledge of the universe and the technology available in 1916, Einstein assumed that such ripples would be “vanishingly small” and nearly impossible to detect. The astronomical discoveries and technological advances over the past century have changed those prospects.<br />
Now for the first time, scientists in the LIGO Scientific Collaboration — with a prominent role played by researchers at MIT and Caltech — have directly observed the ripples of gravitational waves in an instrument on Earth. In so doing, they have again dramatically confirmed Einstein’s theory of general relativity and opened up a new way in which to view the universe.''<br />
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'''原文链接:'''http://news.mit.edu/2016/ligo-first-detection-gravitational-waves-0211<br />
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== Who Benefits from the "Sharing" Economy of Airbnb? ==<br />
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''arXiv:1602.02238v1 [cs.SI] (Submitted on 6 Feb 2016)''<br />
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''by Giovanni Quattrone, Davide Proserpio, Daniele Quercia, Licia Capra, Mirco Musolesi''<br />
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''Sharing economy platforms have become extremely popular in the last few years, and they have changed the way in which we commute, travel, and borrow among many other activities. Despite their popularity among consumers, such companies are poorly regulated. For example, Airbnb, one of the most successful examples of sharing economy platform, is often criticized by regulators and policy makers. While, in theory, municipalities should regulate the emergence of Airbnb through evidence-based policy making, in practice, they engage in a false dichotomy: some municipalities allow the business without imposing any regulation, while others ban it altogether. That is because there is no evidence upon which to draft policies. Here we propose to gather evidence from the Web. After crawling Airbnb data for the entire city of London, we find out where and when Airbnb listings are offered and, by matching such listing information with census and hotel data, we determine the socio-economic conditions of the areas that actually benefit from the hospitality platform. The reality is more nuanced than one would expect, and it has changed over the years. Airbnb demand and offering have changed over time, and traditional regulations have not been able to respond to those changes. That is why, finally, we rely on our data analysis to envision regulations that are responsive to real-time demands, contributing to the emerging idea of "algorithmic regulation".''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.02238<br />
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== How visas shape and make visible the geopolitical architecture of the planet ==<br />
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''arXiv:1601.06314v1 [physics.soc-ph] (Submitted on 23 Jan 2016)''<br />
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''by Meghdad Saeedian, Tayeb Jamali, S. Vasheghani Farahani, G. R. Jafari, Marcel Ausloos''<br />
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''(Translated by -)''<br />
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''The aim of the present study is to provide a picture for geopolitical globalization: the role of all world countries together with their contribution towards globalization is highlighted. In the context of the present study, every country owes its efficiency and therefore its contribution towards structuring the world by the position it holds in a complex global network. The location in which a country is positioned on the network is shown to provide a measure of its "contribution" and "importance". As a matter of fact, the visa status conditions between countries reflect their contribution towards geopolitical globalization. Based on the visa status of all countries, community detection reveals the existence of 4+1 main communities. The community constituted by the developed countries has the highest clustering coefficient equal to 0.9. In contrast, the community constituted by the old eastern European blocks, the middle eastern countries, and the old Soviet Union has the lowest clustering coefficient approximately equal to 0.65. PR China is the exceptional case. Thus, the picture of the globe issued in this study contributes towards understanding "how the world works".''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.06314<br />
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== Complex Contagion of Campaign Donations ==<br />
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''PLoS ONE 2016, 11(4): e0153539''<br />
''DOI: 10.1371/journal.pone.0153539''<br />
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''by V.A. Traag''<br />
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''(Translated by -)''<br />
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''Money is central in US politics, and most campaign contributions stem from a tiny, wealthy elite. Like other political acts, campaign donations are known to be socially contagious. We study how campaign donations diffuse through a network of more than 50 000 elites and examine how connectivity among previous donors reinforces contagion. We find that the diffusion of donations is driven by independent reinforcement contagion: people are more likely to donate when exposed to donors from different social groups than when they are exposed to equally many donors from the same group. Counter-intuitively, being exposed to one side may increase donations to the other side. Although the effect is weak, simultaneous cross-cutting exposure makes donation somewhat less likely. Finally, the independence of donors in the beginning of a campaign predicts the amount of money that is raised throughout a campaign. We theorize that people infer population-wide estimates from their local observations, with elites assessing the viability of candidates, possibly opposing candidates in response to local support. Our findings suggest that theories of complex contagions need refinement and that political campaigns should target multiple communities.''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.07679<br />
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== A mutual information approach to calculating nonlinearity ==<br />
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''Stat Volume 4, Issue 1, pages 291–303, 2015''<br />
''DOI: 10.1002/sta4.96''<br />
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''by Reginald Smith''<br />
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''(Translated by -)''<br />
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''A new method to measure nonlinear dependence between two variables is described using mutual information to analyse the separate linear and nonlinear components of dependence. This technique, which gives an exact value for the proportion of linear dependence, is then compared with another common test for linearity, the Brock, Dechert and Scheinkman test.''<br />
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'''原文链接:'''http://onlinelibrary.wiley.com/doi/10.1002/sta4.96/abstract<br />
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== Jam avoidance with autonomous systems ==<br />
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''Physics and Society,arXiv:1601.07713 [physics.soc-ph] ''<br />
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''by Antoine Tordeux, Sylvain Lassarre ''<br />
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''(Translated by -)''<br />
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''Many car-following models are developed for jam avoidance in highways. Two mechanisms are used to improve the stability: feedback control with autonomous models and increasing of the interaction within cooperative ones. In this paper, we compare the linear autonomous and collective optimal velocity (OV) models. We observe that the stability is significantly increased by adding predecessors in interaction with collective models. Yet autonomous and collective approaches are close when the speed difference term is taking into account. Within the linear OV models tested, the autonomous models including speed difference are sufficient to maximise the stability.''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.07713<br />
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'''原文下载:'''http://120.52.73.76/arxiv.org/pdf/1601.07713v1.pdf<br />
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==The chips are down for Moore’s law ==<br />
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''NATURE,News Feature,Volume 530,Issue 7589,144-147,11 February 2016 ''<br />
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''by M. Mitchell Waldrop ''<br />
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''(Translated by -)''<br />
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''Next month, the worldwide semiconductor industry will formally acknowledge what has become increasingly obvious to everyone involved: Moore's law, the principle that has powered the information-technology revolution since the 1960s, is nearing its end.<br />
A rule of thumb that has come to dominate computing, Moore's law states that the number of transistors on a microprocessor chip will double every two years or so — which has generally meant that the chip's performance will, too. The exponential improvement that the law describes transformed the first crude home computers of the 1970s into the sophisticated machines of the 1980s and 1990s, and from there gave rise to high-speed Internet, smartphones and the wired-up cars, refrigerators and thermostats that are becoming prevalent today. ''<br />
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'''原文链接:'''http://www.nature.com/news/the-chips-are-down-for-moore-s-law-1.19338<br />
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'''原文下载:'''http://www.nature.com/polopoly_fs/1.19338!/menu/main/topColumns/topLeftColumn/pdf/530144a.pdf<br />
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== Evaluating the impact of interdisciplinary research: a multilayer network approach ==<br />
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''Physics and Society,arXiv:1601.06075 [physics.soc-ph] ''<br />
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''by Elisa Omodei, Manlio De Domenico, Alex Arenas ''<br />
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''(Translated by -)''<br />
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''Nowadays, scientific challenges usually require approaches that cross traditional boundaries between academic disciplines, driving many researchers towards interdisciplinarity. Despite its obvious importance, there is a lack of studies on how to quantify the influence of interdisciplinarity on the research impact, posing uncertainty in a proper evaluation for hiring and funding purposes. Here we propose a method based on the analysis of bipartite interconnected multilayer networks of citations and disciplines, to assess scholars, institutions and countries interdisciplinary importance. Using data about physics publications and US patents, we show that our method allows to reveal, using a quantitative approach, that being more interdisciplinary causes -- in the Granger sense -- benefits in scientific productivity and impact. The proposed method could be used by funding agencies, universities and scientific policy decision makers for hiring and funding purposes, and to complement existing methods to rank universities and countries. ''<br />
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'''原文链接:'''http://arxiv.org/abs/1601.06075<br />
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'''原文下载:'''http://arxiv.org/pdf/1601.06075v1.pdf<br />
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==The ecological and evolutionary energetics of hunter-gatherer residential mobility==<br />
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''Physics and Society,arXiv:1602.00631 [physics.soc-ph] ''<br />
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''by Marcus J. Hamilton, Jose Lobo, Eric Rupley, Hyejin Youn, Geoffrey B. West ''<br />
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''(Translated by -)''<br />
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''Residential mobility is deeply entangled with all aspects of hunter-gatherer life ways, and is therefore an issue of central importance in hunter-gatherer studies. Hunter-gatherers vary widely in annual rates of residential mobility, and understanding the sources of this variation has long been of interest to anthropologists and archaeologists. Since mobility is, to a large extent, driven by the need for a continuous supply of food, a natural framework for addressing this question is provided by the metabolic theory of ecology. This provides a powerful framework for formulating formal testable hypotheses concerning evolutionary and ecological constraints on the scale and variation of hunter-gatherer residential mobility. We evaluate these predictions using extant data and show strong support for the hypotheses. We show that the overall scale of hunter-gatherer residential mobility is predicted by average human body size, and the limited capacity of mobile hunter-gatherers to store energy internally. We then show that the majority of variation in residential mobility observed across cultures is predicted by energy availability in local ecosystems. Our results demonstrate that large-scale evolutionary and ecological processes, common to all plants and animals, constrain hunter-gatherers in predictable ways as they move through territories to effectively exploit resources over the course of a year. Moreover, our results extend the scope of the metabolic theory of ecology by showing how it successfully predicts variation in the behavioral ecology of populations within a species. ''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.00631<br />
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'''原文下载:'''https://arxiv.org/ftp/arxiv/papers/1602/1602.00631.pdf<br />
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==Describing People as Particles Isn’t Always a Bad Idea==<br />
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''Nautil.us,ISSUE 033,ATTRACTION ''<br />
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''by PHILIP BALL ''<br />
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''(Translated by -)''<br />
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''Infomercialist and pop psychologist Barbara De Angelis puts it this way: “Love is a force more formidable than any other.” Whether you agree with her or not, De Angelis is doing something we do all the time—she is using the language of physics to describe social phenomena.<br />
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“I was irresistibly attracted to him”; “You can’t force me”; “We recognize the force of public opinion”; “I’m repelled by these policies.” We can’t measure any of these “social forces” in the way that we can measure gravity or magnetic force. But not only has physics-based thinking entered our language, it is also at the heart of many of our most important models of social behavior, from economics to psychology. The question is, do we want it there? ''<br />
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'''原文链接:'''http://nautil.us/issue/33/attraction/describing-people-as-particles-isnt-always-a-bad-idea<br />
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==Bendy bugs inspire roboticists==<br />
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''Science 12 Feb 2016:Vol. 351, Issue 6274, pp. 647 DOI: 10.1126/science.351.6274.647''<br />
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''by Elizabeth Pennisi ''<br />
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''(Translated by -)''<br />
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''Insects, whether they creep or fly, live in a world of hard knocks. Who has not stepped on a cockroach, then raised her shoe to watch the creature get up and scoot under a door? Bees and wasps, for their part, face a never-ending obstacle course of leaves, stems, and petals—bumblebees crash their wings into obstacles as often as once a second. Now, researchers are learning how these creatures bend but don't break. The results do more than explain why cockroaches are so hard to kill. By mimicking the combination of rigid and flexible parts that gives insect exoskeletons and wings their resilience, biomechanicists are making robots tougher. It's quite the contrast from the way engineers have designed most of their machines, but may lead to better robots for search and rescue. ''<br />
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'''原文链接:'''http://science.sciencemag.org/content/351/6274/647<br />
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==Social Norms of Cooperation in Small-Scale Societies==<br />
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''PLoS Comput Biol 12(1): e1004709 ''<br />
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''by Fernando P. Santos, Francisco C. Santos, Jorge M. Pacheco ''<br />
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''(Translated by -)''<br />
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''Indirect reciprocity, besides providing a convenient framework to address the evolution of moral systems, offers a simple and plausible explanation for the prevalence of cooperation among unrelated individuals. By helping someone, an individual may increase her/his reputation, which may change the pre-disposition of others to help her/him in the future. This, however, depends on what is reckoned as a good or a bad action, i.e., on the adopted social norm responsible for raising or damaging a reputation. In particular, it remains an open question which social norms are able to foster cooperation in small-scale societies, while enduring the wide plethora of stochastic affects inherent to finite populations. Here we address this problem by studying the stochastic dynamics of cooperation under distinct social norms, showing that the leading norms capable of promoting cooperation depend on the community size. However, only a single norm systematically leads to the highest cooperative standards in small communities. That simple norm dictates that only whoever cooperates with good individuals, and defects against bad ones, deserves a good reputation, a pattern that proves robust to errors, mutations and variations in the intensity of selection.''<br />
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'''原文链接:'''http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1004709<br />
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==Triumph for gravitational wave hunt==<br />
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''Science 12 Feb 2016:Vol. 351, Issue 6274, pp. 645-646 DOI: 10.1126/science.351.6274.645 ''<br />
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''by Adrian Cho ''<br />
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''(Translated by -)''<br />
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''More than a billion years ago, two black holes—the gravitational ghosts of gigantic stars—spiraled together and collided in space. Ripples in spacetime swept through the universe. Five months ago, they washed past Earth, and physicists detected gravitational waves for the first time. The long-awaited discovery—announced this week—marks a triumph for the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of huge instruments in Washington state and Louisiana. It also promises to give researchers a whole new set of eyes on the universe. Until now, astronomers have probed it mainly through electromagnetic radiation such as light. Now, gravitational waves will enable them to detect astrophysical objects that they can't see. And physicists will be able to study realms of extreme gravity that until now only theorists could explore. Other gravitational-wave detections may come soon, both from LIGO and from VIRGO, a freshly upgraded Italian detector scheduled to be switched on later this year. ''<br />
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'''原文链接:'''http://dx.doi.org/10.1126/science.351.6274.645<br />
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==The happiness paradox: your friends are happier than you==<br />
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''Social and Information Networks,arXiv:1602.02665 [cs.SI]''<br />
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''by Johan Bollen, Bruno Gonçalves, Ingrid van de Leemput, Guangchen Ruan ''<br />
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''(Translated by -)''<br />
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''Most individuals in social networks experience a so-called Friendship Paradox: they are less popular than their friends on average. This effect may explain recent findings that widespread social network media use leads to reduced happiness. However the relation between popularity and happiness is poorly understood. A Friendship paradox does not necessarily imply a Happiness paradox where most individuals are less happy than their friends. Here we report the first direct observation of a significant Happiness Paradox in a large-scale online social network of $39,110$ Twitter users. Our results reveal that popular individuals are indeed happier and that a majority of individuals experience a significant Happiness paradox. The magnitude of the latter effect is shaped by complex interactions between individual popularity, happiness, and the fact that users cluster assortatively by level of happiness. Our results indicate that the topology of online social networks and the distribution of happiness in some populations can cause widespread psycho-social effects that affect the well-being of billions of individuals.''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.02665<br />
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'''原文下载:'''http://arxiv.org/pdf/1602.02665v1.pdf<br />
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==Extreme robustness of scaling in sample space reducing processes explains Zipf's law in diffusion on directed networks==<br />
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''Physics and Society,arXiv:1602.05530 [physics.soc-ph] ''<br />
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''by Bernat Corominas-Murtra, Rudolf Hanel, Stefan Thurner ''<br />
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''(Translated by -)''<br />
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''It has been shown recently that a specific class of path-dependent stochastic processes, which reduce their sample space as they unfold, lead to exact scaling laws in frequency and rank distributions. Such Sample Space Reducing processes (SSRP) offer an alternative new mechanism to understand the emergence of scaling in countless processes. The corresponding power law exponents were shown to be related to noise levels in the process. Here we show that the emergence of scaling is not limited to the simplest SSRPs, but holds for a huge domain of stochastic processes that are characterized by non-uniform prior distributions. We demonstrate mathematically that in the absence of noise the scaling exponents converge to $-1$ (Zipf's law) for almost all prior distributions. As a consequence it becomes possible to fully understand targeted diffusion on weighted directed networks and its associated scaling laws law in node visit distributions. The presence of cycles can be properly interpreted as playing the same role as noise in SSRPs and, accordingly, determine the scaling exponents. The result that Zipf's law emerges as a generic feature of diffusion on networks, regardless of its details, and that the exponent of visiting times is related to the amount of cycles in a network could be relevant for a series of applications in traffic-, transport- and supply chain management.''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.05530<br />
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'''原文下载:'''http://120.52.73.75/arxiv.org/pdf/1602.05530v3.pdf<br />
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==Zika Virus Community Response==<br />
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''by Yaneer Bar-Yam,New England Complex Systems Institute and Rebecca Menapace, Brandeis University. ''<br />
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''Here we propose a set of community-level strategies for reducing mosquito reproduction, reducing exposure to the virus, and constraining its geographical spread. The benefits of collective effects lead to the importance of strategies in which multiple individuals perform actions which mutually reinforce each other. The rapid two to four week generation time of the primary mosquito species carrying the virus, Aedes aegypti, means that reducing its reproduction rate may confine it to smaller areas, halting its spread and subsequently enabling more targeted efforts to eliminate the virus in those areas.''<br />
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'''原文链接:'''http://necsi.edu/research/social/pandemics/zikaresponse<br />
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'''原文下载:'''http://necsi.edu/research/social/pandemics/ZikaResponse2.pdf<br />
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==Four billion people facing severe water scarcity ==<br />
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''Science Advances 12 Feb 2016:Vol. 2, no. 2, e1500323 DOI: 10.1126/sciadv.1500323''<br />
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''by Mesfin M. Mekonnen* and Arjen Y. Hoekstra ''<br />
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''(Translated by -)''<br />
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''Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare. ''<br />
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'''原文链接:'''http://advances.sciencemag.org/content/2/2/e1500323<br />
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==Human Atlas: A Tool for Mapping Social Networks ==<br />
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''Social and Information Networks ,arXiv:1602.02426 [cs.SI] ''<br />
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''by Martin Saveski, Eric Chu, Soroush Vosoughi, Deb Roy ''<br />
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''(Translated by -)''<br />
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''Most social network analyses focus on online social networks. While these networks encode important aspects of our lives they fail to capture many real-world connections. Most of these connections are, in fact, public and known to the members of the community. Mapping them is a task very suitable for crowdsourcing: it is easily broken down in many simple and independent subtasks. Due to the nature of social networks -- presence of highly connected nodes and tightly knit groups -- if we allow users to map their immediate connections and the connections between them, we will need few participants to map most connections within a community. To this end, we built the Human Atlas, a web-based tool for mapping social networks. To test it, we partially mapped the social network of the MIT Media Lab. We ran a user study and invited members of the community to use the tool. In 4.6 man-hours, 22 participants mapped 984 connections within the lab, demonstrating the potential of the tool. ''<br />
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'''原文链接:'''http://arxiv.org/abs/1602.02426<br />
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'''原文下载:'''http://arxiv.org/pdf/1602.02426v2.pdf<br />
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==Beyond Ebola==<br />
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''Science 19 Feb 2016:Vol. 351, Issue 6275, pp. 815-816 DOI: 10.1126/science.aad8521 ''<br />
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''by Janet Currie, Bryan Grenfell, Jeremy Farrar ''<br />
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''On 14 January 2016, Liberia was declared Ebola-free. A new case was identified shortly after the announcement, but it is nevertheless clear that the West African epidemic has moved on to a more hopeful phase. What lessons can be drawn from the Ebola crisis to help the international community to prepare for and respond to the next global epidemic? This question is particularly pertinent given the recent declaration of the Zika virus as a public health emergency. ''<br />
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'''原文链接:'''http://dx.doi.org/10.1126/science.aad8521<br />
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==What sparked the Cambrian explosion?==<br />
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''NATURE,News Feature,Volume 530,Issue 7590, 268–270 (18 February 2016) ''<br />
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''by Douglas Fox ''<br />
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''(Translated by -)''<br />
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''An evolutionary burst 540 million years ago filled the seas with an astonishing diversity of animals. The trigger behind that revolution is finally coming into focus. ''<br />
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A series of dark, craggy pinnacles rises 80 metres above the grassy plains of Namibia. The peaks call to mind something ancient — the burial mounds of past civilizations or the tips of vast pyramids buried by the ages.<br />
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'''原文链接:'''http://dx.doi.org/10.1038/530268a<br />
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==Gut bacteria that prevent growth impairments transmitted by microbiota from malnourished children==<br />
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''Science 19 Feb 2016:Vol. 351, Issue 6275, DOI: 10.1126/science.aad3311''<br />
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''by BY LAURA V. BLANTON, MARK R. CHARBONNEAU, TAREK SALIH, MICHAEL J. BARRATT, SIDDARTH VENKATESH, OLGA ILKAVEYA, SATHISH SUBRAMANIAN, MARK J. MANARY, INDI TREHAN, JOSH M. JORGENSEN, YUE-MEI FAN, BERNARD HENRISSAT, SEMEN A. LEYN, DMITRY A. RODIONOV, ANDREI L. OSTERMAN, KENNETH M. MALETA, CHRISTOPHER B. NEWGARD, PER ASHORN, KATHRYN G. DEWEY, JEFFREY I. GORDON''<br />
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''(Translated by -)''<br />
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''Malnutrition in children is a persistent challenge that is not always remedied by improvements in nutrition. This is because a characteristic community of gut microbes seems to mediate some of the pathology. Human gut microbes can be transplanted effectively into germ-free mice to recapitulate their associated phenotypes. Using this model, Blanton et al. found that the microbiota of healthy children relieved the harmful effects on growth caused by the microbiota of malnourished children. In infant mammals, chronic undernutrition results in growth hormone resistance and stunting. In mice, Schwarzer et al. showed that strains of Lactobacillus plantarum in the gut microbiota sustained growth hormone activity via signaling pathways in the liver, thus overcoming growth hormone resistance. Together these studies reveal that specific beneficial microbes could potentially be exploited to resolve undernutrition syndromes. ''<br />
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'''原文链接:'''http://science.sciencemag.org/content/351/6275/aad3311<br />
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==The scope and limits of simulation in automated reasoning==<br />
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''Artificial Intelligence,Volume 233, April 2016, Pages 60–72 ''<br />
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''by Ernest Davis, Gary Marcus ''<br />
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''In scientific computing and in realistic graphic animation, simulation – that is, step-by-step calculation of the complete trajectory of a physical system – is one of the most common and important modes of calculation. In this article, we address the scope and limits of the use of simulation, with respect to AI tasks that involve high-level physical reasoning. We argue that, in many cases, simulation can play at most a limited role. Simulation is most effective when the task is prediction, when complete information is available, when a reasonably high quality theory is available, and when the range of scales involved, both temporal and spatial, is not extreme. When these conditions do not hold, simulation is less effective or entirely inappropriate. We discuss twelve features of physical reasoning problems that pose challenges for simulation-based reasoning. We briefly survey alternative techniques for physical reasoning that do not rely on simulation. ''<br />
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'''原文链接:'''http://dx.doi.org/10.1016/j.artint.2015.12.003<br />
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==Tensegrity, Dynamic Networks, and Complex Systems Biology: Emergence in Structural and Information Networks Within Living Cells==<br />
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''Complex Systems Science in Biomedicine,Part of the series Topics in Biomedical Engineering International Book Series pp 283-310 ''<br />
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''by Sui Huang, Cornel Sultan, Donald E. Ingber ''<br />
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''The genomic revolution has led to the systematic characterization of all the genes of the genome and the proteins they encode. But we still do not fully understand how many cell behaviors are controlled, because many important biological properties of cells emerge at the whole-system level from the collective action of thousands of molecular components, which is orchestrated through specific regulatory interactions. In this chapter we present two distinct approaches based on the concept of molecular networks to understand two fundamental system properties of living cells: their ability to maintain their shape and mechanical stability, and their ability to express stable, discrete cell phenotypes and switch between them. We first describe how structural networks built using the principles of tensegrity architecture and computational models that incorporate these features can predict many of the complex mechanical behaviors that are exhibited by living mammalian cells. We then discuss how genome-wide biochemical signaling networks produce “attractor” states that may represent the stable cell phenotypes, such as growth, differentiation, and apoptosis, and which explain how cells can make discrete cell fate decisions in the presence of multiple conflicting signals. These network-based concepts help to bridge the apparent gap between emergent system features characteristic of living cells and the underlying molecular processes. ''<br />
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'''原文链接:'''http://link.springer.com/chapter/10.1007%2F978-0-387-33532-2_11<br />
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==Step by Step to Stability and Peace in Syria==<br />
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''New England Complex Systems Institute,210 Broadway Suite 101 Cambridge MA 02139, USA,(Dated February 9, 2016) ''<br />
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''by Raphael Parens, Yaneer Bar-Yam ''<br />
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''The revolution and Civil War in Syria has led to substantial death and suffering, a massive refugee crisis, and growth of ISIS extremism and its terror attacks globally. Conflict between disparate groups is ongoing. Here we propose that interventions should be pursued to stop specific local conflicts, creating safe zones, that can be expanded gradually and serve as examples for achieving a comprehensive solution for safety, peace and stable local governance in Syria. ''<br />
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(此处翻译)<br />
<br />
<br />
'''原文链接:'''http://www.necsi.edu/research/ethnicviolence/stepbystep.html<br />
<br />
'''原文下载:'''http://www.necsi.edu/research/ethnicviolence/stepbystep.pdf<br />
<br />
==The likely determines the unlikely==<br />
<br />
''Physics and Society,arXiv:1602.05272 [physics.soc-ph] ''<br />
<br />
''by Xiaoyong Yan, Petter Minnhagen, Henrik Jeldtoft Jensen ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''We point out that the functional form describing the frequency of sizes of events in complex systems (e.g. earthquakes, forest fires, bursts of neuronal activity) can be obtained from maximal likelihood inference, which, remarkably, only involve a few available observed measures such as number of events, total event size and extremes. Most importantly, the method is able to predict with high accuracy the frequency of the rare extreme events. To be able to predict the few, often big impact events, from the frequent small events is of course of great general importance. For a data set of wind speed we are able to predict the frequency of gales with good precision. We analyse several examples ranging from the shortest length of a recruit to the number of Chinese characters which occur only once in a text.''<br />
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(此处翻译)<br />
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'''原文链接:'''http://arxiv.org/abs/1602.05272<br />
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'''原文下载:'''http://arxiv.org/pdf/1602.05272v1.pdf<br />
<br />
==The International Postal Network and Other Global Flows As Proxies for National Wellbeing ==<br />
<br />
''Computers and Society,arXiv:1601.06028 [cs.CY] ''<br />
<br />
''by Desislava Hristova, Alex Rutherford, Jose Anson, Miguel Luengo-Oroz, Cecilia Mascolo ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''The digital exhaust left by flows of physical and digital commodities provides a rich measure of the nature, strength and significance of relationships between countries in the global network. With this work, we examine how these traces and the network structure can reveal the socioeconomic profile of different countries. We take into account multiple international networks of physical and digital flows, including the previously unexplored international postal network. By measuring the position of each country in the Trade, Postal, Migration, International Flights, IP and Digital Communications networks, we are able to build proxies for a number of crucial socioeconomic indicators such as GDP per capita and the Human Development Index ranking along with twelve other indicators used as benchmarks of national wellbeing by the United Nations and other international organisations. In this context, we have also proposed and evaluated a global connectivity degree measure applying multiplex theory across the six networks that accounts for the strength of relationships between countries. We conclude with a multiplex community analysis of the global flow networks, showing how countries with shared community membership over multiple networks have similar socioeconomic profiles. Combining multiple flow data sources into global multiplex networks can help understand the forces which drive economic activity on a global level. Such an ability to infer proxy indicators in a context of incomplete information is extremely timely in light of recent discussions on measurement of indicators relevant to the Sustainable Development Goals. ''<br />
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(此处翻译)<br />
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'''原文链接:'''http://arxiv.org/abs/1601.06028<br />
<br />
==Universal resilience patterns in complex networks ==<br />
<br />
''Nature 530, 307–312 (18 February 2016) doi:10.1038/nature16948''<br />
<br />
''by Jianxi Gao,Baruch Barzel& Albert-László Barabási ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''Resilience, a system’s ability to adjust its activity to retain its basic functionality when errors, failures and environmental changes occur, is a defining property of many complex systems1. Despite widespread consequences for human health2, the economy3 and the environment4, events leading to loss of resilience—from cascading failures in technological systems5 to mass extinctions in ecological networks6—are rarely predictable and are often irreversible. These limitations are rooted in a theoretical gap: the current analytical framework of resilience is designed to treat low-dimensional models with a few interacting components7, and is unsuitable for multi-dimensional systems consisting of a large number of components that interact through a complex network. Here we bridge this theoretical gap by developing a set of analytical tools with which to identify the natural control and state parameters of a multi-dimensional complex system, helping us derive effective one-dimensional dynamics that accurately predict the system’s resilience. The proposed analytical framework allows us systematically to separate the roles of the system’s dynamics and topology, collapsing the behaviour of different networks onto a single universal resilience function. The analytical results unveil the network characteristics that can enhance or diminish resilience, offering ways to prevent the collapse of ecological, biological or economic systems, and guiding the design of technological systems resilient to both internal failures and environmental changes. ''<br />
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(此处翻译)<br />
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'''原文链接:'''http://www.nature.com/nature/journal/v530/n7590/full/nature16948.html<br />
<br />
==Complexity theory and financial regulation ==<br />
<br />
''Science 19 Feb 2016:Vol. 351, Issue 6275, pp. 818-819 DOI: 10.1126/science.aad0299''<br />
<br />
''by BY STEFANO BATTISTON, J. DOYNE FARMER, ANDREAS FLACHE, DIEGO GARLASCHELLI, ANDREW G. HALDANE, HANS HEESTERBEEK, CARS HOMMES, CARLO JAEGER, ROBERT MAY, MARTEN SCHEFFER ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''Traditional economic theory could not explain, much less predict, the near collapse of the financial system and its long-lasting effects on the global economy. Since the 2008 crisis, there has been increasing interest in using ideas from complexity theory to make sense of economic and financial markets. Concepts, such as tipping points, networks, contagion, feedback, and resilience have entered the financial and regulatory lexicon, but actual use of complexity models and results remains at an early stage. Recent insights and techniques offer potential for better monitoring and management of highly interconnected economic and financial systems and, thus, may help anticipate and manage future crises. ''<br />
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(此处翻译)<br />
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'''原文链接:'''http://science.sciencemag.org/content/351/6275/818<br />
<br />
==Networks of plants: how to measure similarity in vegetable species==<br />
<br />
''Populations and Evolution ,arXiv:1602.05887 [q-bio.PE] ''<br />
<br />
''by Gianna Vivaldo, Elisa Masi, Camilla Pandolfi, Stefano Mancuso, Guido Caldarelli ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''Despite the common misconception of nearly static organisms, plants do interact continuously with the environment and with each other. It is fair to assume that during their evolution they developed particular features to overcome problems and to exploit possibilities from environment. In this paper we introduce various quantitative measures based on recent advancements in complex network theory that allow to measure the effective similarities of various species. By using this approach on the similarity in fruit-typology ecological traits we obtain a clear plant classification in a way similar to traditional taxonomic classification. This result is not trivial, since a similar analysis done on the basis of diaspore morphological properties do not provide any clear parameter to classify plants species. Complex network theory can then be used in order to determine which feature amongst many can be used to distinguish scope and possibly evolution of plants. Future uses of this approach range from functional classification to quantitative determination of plant communities in nature. ''<br />
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<br />
(此处翻译)<br />
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'''原文链接:'''http://arxiv.org/abs/1602.05887<br />
<br />
'''原文下载:'''http://arxiv.org/pdf/1602.05887v1.pdf<br />
<br />
==The Mobile Territorial Lab: a multilayered and dynamic view on parents’ daily lives==<br />
<br />
''EPJ Data Science20165:3 DOI: 10.1140/epjds/s13688-016-0064-6© Centellegher et al. 2016 ''<br />
<br />
''by Simone Centellegher, Marco De Nadai, Michele Caraviello, Chiara Leonardi, Michele Vescovi, Yusi Ramadian, Nuria Oliver, Fabio Pianesi, Alex Pentland, Fabrizio Antonelli and Bruno Lepri''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''The exploration of people’s everyday life has long been of interest to social scientists. Recent years have witnessed a growing interest in analyzing human behavioral data generated by technology (e.g. mobile phones). To date, a few large-scale studies have been designed to measure human behaviors and interactions using multiple sources of data. A common characteristic of these studies is the population under investigation: students having similar daily routines and needs. This choice constraints the range of behaviors, of places and the generalization of the results. In order to widen this line of studies, we focus on a different target group: parents with young children aged 0 through 10 years. Children influence multiple aspects of their parents’ lives, from the satisfaction of basic human needs and the fulfillment of social roles to their financial status and sleep quality.<br />
<br />
In this paper, we describe the Mobile Territorial Lab (MTL) project, a longitudinal living lab which has been sensing by means of technology (mobile phones) the lives of more than 100 parents in different areas of the Trentino region in Northern Italy. We present the preliminary results after two years of experimentation of, to the best of our knowledge, the most complete picture of parents’ daily lives. Through the collection and analysis of the collected data, we created a multi-layered view of the participants’ lives, tracking social interactions, mobility routines, spending patterns, and personality characteristics.<br />
<br />
Overall, our results prove the relevance of living lab approaches to measure human behaviors and interactions, which can pave the way to new studies exploiting a richer number of behavioral indicators. Moreover, we believe that the proposed methodology and the collected data could be very valuable for researchers from different disciplines such as social psychology, sociology, computer science, economy, etc., which are interested in understanding human behaviour. ''<br />
<br />
<br />
(此处翻译)<br />
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'''原文链接:'''http://epjdatascience.springeropen.com/articles/10.1140/epjds/s13688-016-0064-6<br />
<br />
'''原文下载:'''http://download.springer.com/static/pdf/619/art%253A10.1140%252Fepjds%252Fs13688-016-0064-6.pdf?originUrl=http%3A%2F%2Fepjdatascience.springeropen.com%2Farticle%2F10.1140%2Fepjds%2Fs13688-016-0064-6&token2=exp=1468739332~acl=%2Fstatic%2Fpdf%2F619%2Fart%25253A10.1140%25252Fepjds%25252Fs13688-016-0064-6.pdf*~hmac=8ea3eaaacf75f01e5347d41b7f55935a3bf913ef15f2b1a432bc61e21bee8180<br />
<br />
==Measuring the Complexity of Continuous Distributions==<br />
<br />
''Entropy 2016, 18(3), 72; doi:10.3390/e18030072''<br />
<br />
''by Guillermo Santamaría-Bonfil, Nelson Fernández, and Carlos Gershenson ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''We extend previously proposed measures of complexity, emergence, and self-organization to continuous distributions using differential entropy. Given that the measures were based on Shannon’s information, the novel continuous complexity measures describe how a system’s predictability changes in terms of the probability distribution parameters. This allows us to calculate the complexity of phenomena for which distributions are known. We find that a broad range of common parameters found in Gaussian and scale-free distributions present high complexity values. We also explore the relationship between our measure of complexity and information adaptation.''<br />
<br />
<br />
(此处翻译)<br />
<br />
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'''原文链接:'''http://www.mdpi.com/1099-4300/18/3/72<br />
<br />
'''原文下载:'''http://www.mdpi.com/1099-4300/18/3/72/pdf<br />
<br />
==Modern Milgram experiment sheds light on power of authority==<br />
<br />
''Nature,Volume 530,Issue 7591,News ''<br />
<br />
''by Alison Abbott ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''More than 50 years after a controversial psychologist shocked the world with studies that revealed people’s willingness to harm others on order, a team of cognitive scientists has carried out an updated version of the iconic ‘Milgram experiments’.<br />
Their findings may offer some explanation for Stanley Milgram's uncomfortable revelations: when following commands, they say, people genuinely feel less responsibility for their actions — whether they are told to do something evil or benign. ''<br />
<br />
<br />
(此处翻译)<br />
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<br />
'''原文链接:'''http://www.nature.com/news/modern-milgram-experiment-sheds-light-on-power-of-authority-1.19408<br />
<br />
'''原文下载:'''http://www.nature.com/polopoly_fs/1.19408!/menu/main/topColumns/topLeftColumn/pdf/nature.2016.19408.pdf<br />
<br />
==Evolution in the Anthropocene==<br />
<br />
''Science 26 Feb 2016:Vol. 351, Issue 6276, pp. 922-923 DOI: 10.1126/science.aad6756''<br />
<br />
''by François Sarrazin, Jane Lecomte ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''Most current conservation strategies focus on the immediate social, cultural, and economic values of ecological diversity, functions, and services (1). For example, the Intergovernmental Platform on Biodiversity and Ecosystem Services (2) mostly addresses the utilitarian management of biodiversity from local to global scales. However, besides urgent diagnosis and actions (3, 4), processes that occur over evolutionary time scales are equally important for biodiversity conservation. Strategizing for conservation of nature at such long time scales will help to preserve the function—and associated services—of the natural world, as well as providing opportunities for it to evolve. This approach will foster a long-term, sustainable interaction that promotes both the persistence of nature and the wellbeing of humans.''<br />
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<br />
(此处翻译)<br />
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'''原文链接:'''http://science.sciencemag.org/content/351/6276/922<br />
<br />
==Global Patterns of Human Synchronization==<br />
<br />
''Physics and Society ,arXiv:1602.06219 [physics.soc-ph] ''<br />
<br />
''by Alfredo J. Morales, Vaibhav Vavilala, Rosa M. Benito, Yaneer Bar-Yam ''<br />
<br />
''(Translated by -)''<br />
<br />
<br />
''Social media are transforming global communication and coordination and provide unprecedented opportunities for studying socio-technical domains. Here we study global dynamical patterns of communication on Twitter across many scales. Underlying the observed patterns is both the diurnal rotation of the earth, day and night, and the synchrony required for contingency of actions between individuals. We find that urban areas show a cyclic contraction and expansion that resembles heartbeats linked to social rather than natural cycles. Different urban areas have characteristic signatures of daily collective activities. We show that the differences detected are consistent with a new emergent global synchrony that couples behavior in distant regions across the world. Although local synchrony is the major force that shapes the collective behavior in cities, a larger-scale synchronization is beginning to occur. ''<br />
<br />
<br />
(此处翻译)<br />
<br />
[[Category:旧词条迁移]]<br />
'''原文链接:'''http://arxiv.org/abs/1602.06219</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%B8%89%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.4%E6%9C%88%E6%96%87%E7%AB%A0)&diff=15172
复杂文摘翻译第三期-(摘自Complex Digest 2016.4月文章)
2020-10-14T14:02:34Z
<p>Thingamabob:创建页面,内容为“复杂文摘翻译第三期-(摘自Complex Digest 2016.4月文章) ==复杂社会系统中的危机:以智利事件为例的一个社会理论观点 (Crisis…”</p>
<hr />
<div>复杂文摘翻译第三期-(摘自Complex Digest 2016.4月文章)<br />
<br />
<br />
==复杂社会系统中的危机:以智利事件为例的一个社会理论观点 (Crisis in complex social systems: A social theory view illustrated with the chilean case) ==<br />
From onlinelibrary.wiley.com <br />
April 1, 12:39 AM<br />
<br />
By Aldo Mascareño, Eric Goles, and Gonzalo A. Ruz<br />
<br />
(Translated by -王与剑-生物物理学-呼和浩特)<br />
<br />
''The article argues that crises are a distinctive feature of complex social systems. A quest for connectivity of communication leads to increase systems' own robustness by constantly producing further connections. When some of these connections have been successful in recent operations, the system tends to reproduce the emergent pattern, thereby engaging in a non-reflexive, repetitive escalation of more of the same communication. This compulsive growth of systemic communication in crisis processes, or logic of excess, resembles the dynamic of self-organized criticality. Accordingly, we first construct the conceptual foundations of our approach. Second, we present three core assumptions related to the generative mechanism of social crises, their temporal transitions (incubation, contagion, restructuring), and the suitable modeling techniques to represent them. Third, we illustrate the conceptual approach with a percolation model of the crisis in Chilean education system.'' <br />
<br />
<br />
===Jake编辑===<br />
<br />
这篇文章认为:危机是复杂社会系统中一种突出的特征。对于交流的连通性的要求会以一种持续地产生更多连接的方式导致系统自身的鲁棒性增加。当这些连接的一部分在近期的一些操作中成功了之后,这个系统就倾向于复制这一自然发生的模式,因此进入了一个无自反性,重复升级,扩大相同联系的状态。这种危机发展中的系统联系的强制增长,或者说逻辑过剩,类似于自发组织临界性动力学。因此,我们首先建立我们这个方法的概念上的根据。其次,我们提出关于社会危机产生机制的三个核心假设,他们的暂时的过渡(潜伏,蔓延,调整),并且用合适的模型来代表他们。第三,我们举例用理论方法渗透模型,解释智利教育系统的危机。<br />
<br />
<br />
这篇文章讲述了,危机是复杂社会系统中很有特色的一部分。对于交流的紧密性的要求,导致通过不断制造更多的连接使系统自身的鲁棒性增加。当这些连接的一部分在近期的一些操作中成功了之后,这个系统就倾向于复制这一自然发生的模式,因此进入了一个无自反性,重复升级,扩大相同联系的状态。这种危机发展中的系统联系的强制增长,或者说逻辑过剩,类似于自发组织临界性动力学。因此,我们首先建立我们这个方法的概念上的根据。其次,我们提出关于社会危机产生机制的三个核心假设,他们的暂时的过渡(潜伏,蔓延,调整),并且用合适的模型来代表他们。第三,我们举例用理论方法渗透模型,解释智利教育系统的危机。<br />
<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1002/cplx.21778<br />
<br />
==Does Stress Speed Up Evolution?==<br />
From nautil.us <br />
April 1, 5:36 PM<br />
<br />
By Andreas von Bubnoff<br />
<br />
(Translated by -)<br />
<br />
''Organisms under stress have a higher mutation rate, even though they are not dividing.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://nautil.us/issue/34/adaptation/does-stress-speed-up-evolution<br />
<br />
== 遗传环路设计自动化 (Genetic circuit design automation) ==<br />
From Science 01 Apr 2016:Vol. 352, Issue 6281 <br />
April 1, 9:45 PM<br />
<br />
By Alec A. K. Nielsen, et al.<br />
<br />
(Translated by - 刘清晴)<br />
<br />
''Computation can be performed in living cells by DNA-encoded circuits that process sensory information and control biological functions. Their construction is time-intensive, requiring manual part assembly and balancing of regulator expression. We describe a design environment, Cello, in which a user writes Verilog code that is automatically transformed into a DNA sequence. Algorithms build a circuit diagram, assign and connect gates, and simulate performance. Reliable circuit design requires the insulation of gates from genetic context, so that they function identically when used in different circuits. We used Cello to design 60 circuits for Escherichia coli (880,000 base pairs of DNA), for which each DNA sequence was built as predicted by the software with no additional tuning. Of these, 45 circuits performed correctly in every output state (up to 10 regulators and 55 parts), and across all circuits 92% of the output states functioned as predicted. Design automation simplifies the incorporation of genetic circuits into biotechnology projects that require decision-making, control, sensing, or spatial organization.''<br />
<br />
===Jake修改===<br />
<br />
在活细胞中,那些能够传递传感信息并控制活细胞各种生物学功能的DNA编码的分子环路可以实现计算。这些计算的构造是时间密集的,需要手动组装各种部件(part)并使各种调节因子(regulator)表达达到平衡。我们构建了一个名叫Cello的设计环境,用户可以用Verilog语言进行编程,程序会自动转化为DNA序列。通过算法生成电路图,分配和链接逻辑门,并进行性能模拟。可靠的环路设计需要将逻辑门从遗传背景中孤立出来,使它们在用于不同的分子环路时都同样能够发挥功能。我们使用Cello为大肠杆菌(Escherichia coli,其DNA包含88万个碱基对)设计了60条遗传环路。其中每条DNA序列都是由软件生成的,并没有进行进一步的调整。在这些遗传环路中,有45条环路在每一个输出状态中(多达10个调节因子和55个部件)都执行正确。包括所有这些环路在内,92%的输出状态都符合预期。将遗传环路设计并入生物技术项目(译注:即人工设计遗传环路)需要决策、控制、传感以及空间组织,设计自动化简化了这一过程。<br />
<br />
===原文===<br />
<br />
在活细胞中,计算可以通过DNA编码的分子环路来实现。这些环路传递感觉信息并控制活细胞的各种生物学功能。这些计算的结构是时间密集的,需要组装各种部件(part)并使各种调节因子(regulator)的表达达到平衡。我们构建了一个名叫Cello的设计环境,用户可以用Verilog语言进行编程,程序会自动转化为DNA序列。通过算法生成环路图,赋值和逻辑门连接,并进行性能模拟。可靠的环路设计需要将逻辑门从遗传背景中孤立出来,使它们在用于不同的分子环路时都同样能够发挥功能。我们使用Cello为大肠杆菌(Escherichia coli,其DNA包含88万个碱基对)设计了60条遗传环路。其中每条DNA序列都是由软件生成的,并没有进行进一步的调整。在这些遗传环路中,有45条环路在每一个输出状态中(多达10个调节因子和55个部件)都执行正确。包括所有这些环路在内,92%的输出状态都符合预期。将遗传环路设计并入生物技术项目(译注:即人工设计遗传环路)需要决策、控制、传感以及空间组织,设计自动化简化了这一过程。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1126/science.aac7341<br />
<br />
==一个生物体能否大如星系?Can a Living Creature Be as Big as a Galaxy?==<br />
From nautil.us<br />
April 1, 7:38 PM<br />
<br />
By Gregory Laughlin<br />
<br />
(Translated by -陈开壮, Edited by [[Jake]])<br />
<br />
''Why life is constrained to be about the sizes we see on Earth.''<br />
<br />
''The size of things in our universe runs all the way from the tiny 10^-19 meter scale that characterizes quark interactions, to the cosmic horizon 10^26 meters away. In these 45 possible orders of magnitude, life, as far as we know it, is confined to a relatively tiny bracket of just over nine orders of magnitude, roughly in the middle of the universal range: Bacteria and viruses can measure less than a micron, or 10^-6 meters, and the height of the largest trees reaches roughly 100 meters. The honey fungus that lives under the Blue Mountains in Oregon, and is arguably a single living organism, is about 4 kilometers across.When it comes to known sentient life, the range in scale is even smaller, at about three orders of magnitude. ''<br />
<br />
===Jake修改===<br />
<br />
我们宇宙中事物的大小几乎都在小至10^-19米以夸克相互作用为尺度到大至10^26米宇宙量级之间。在这45个可能的数量级中,生命正如我们了解到的那样被限定在9个数量级这个非常窄的区间上,这基本上是在宇宙(尺度)范围的中间:细菌和病毒的测量值不到1微米即10^-6米,而高度最高的树粗略计算在100米左右。我们知道生活在俄勒冈蓝山脚下的蜜环菌(译者注:一种广泛分布于北美北部和欧洲的菌)的尺度大约可以绵延4公里,而这被认为是一种单一的生命体。而当我们限定在有知觉的生物,则它们的尺度的范围就更小了,大约为3这个数量级。<br />
<br />
===原文===<br />
<br />
为什么生命被限定在我们在地球上大约能看到的尺度呢?<br />
<br />
我们宇宙中物质的大小几乎都在小至10^-19米以夸克相互作用为尺度到大至10^26米宇宙水平远之间,这45个可能的数量级中,正如我们了解到的,生命被相对的仅限制在数量级略多于9这个小小水平上,在宇宙(尺度)中间范围的大概是:细菌和病毒的测量值不到1微米即10^-6米,而高度最高的树粗略计算在100米。生活在俄勒冈蓝山脚下被确证为单个生物体的蜜环菌(译者注:一种广泛分布于北美北部和欧洲的菌)大约可以绵延4公里。而当说起有知觉的生物,这个尺度的范围甚至更小,在大约为3这个数量级。<br />
<br />
'''原文链接:'''http://nautil.us/issue/34/adaptation/can-a-living-creature-be-as-big-as-a-galaxy<br />
<br />
==信息驱动协调现象的动力学:基于转移熵的分析 The dynamics of information-driven coordination phenomena: A transfer entropy analysis==<br />
From Science Advances 01 Apr 2016:Vol. 2, no. 4, e1501158<br />
April 2, 8:09 PM<br />
<br />
By Javier Borge-Holthoefer, Nicola Perra, Bruno Gonçalves, Sandra González-Bailón, Alex Arenas, Yamir Moreno, and Alessandro Vespignani<br />
<br />
(Translated by 蔡嘉文,Edited by [[Jake]])<br />
<br />
''Data from social media provide unprecedented opportunities to investigate the processes that govern the dynamics of collective social phenomena. We consider an information theoretical approach to define and measure the temporal and structural signatures typical of collective social events as they arise and gain prominence. We use the symbolic transfer entropy analysis of microblogging time series to extract directed networks of influence among geolocalized subunits in social systems. This methodology captures the emergence of system-level dynamics close to the onset of socially relevant collective phenomena. The framework is validated against a detailed empirical analysis of five case studies. In particular, we identify a change in the characteristic time scale of the information transfer that flags the onset of information-driven collective phenomena. Furthermore, our approach identifies an order-disorder transition in the directed network of influence between social subunits. In the absence of clear exogenous driving, social collective phenomena can be represented as endogenously driven structural transitions of the information transfer network. This study provides results that can help define models and predictive algorithms for the analysis of societal events based on open source data.''<br />
<br />
===Jake修改===<br />
<br />
社会媒体的数据为我们提供了前所未有的机会来研究群体社会现象背后的动力学因素。我们提出了一种基于信息论的方法来定义和测量在集体社会事件出现和爆发时的时序和结构特征。我们利用符号转移熵的方法对微博的时间序列进行分析,提取出社会系统中地理子块相互影响的有向网络。这种方法可以成功捕获社会集体行为开始形成时的系统级动态的涌现。我们通过五个细致的实证案例分析来验证我们的这个框架。具体来说,我们定义了一种在信息传递过程的时间尺度上的变化,这种变化标志着信息驱动的集体现象的开始。进一步地,我们的方法识别出了在社会子单元的有向网络中的有序-无序的相变过程。在缺失明确外源性驱动的情况下,社会集体现象可以表示为内生驱动的信息传输网络的结构性相变。这项研究提供的结果,可以帮助研究者定义模型和预测算法来对基于开源数据的社会事件进行分析。<br />
<br />
===原文===<br />
<br />
社会媒体的数据提供了前所未有的机会来观察集体社会现象背后的推动因素。我们考虑使用一种信息论的方法来定义和测量集体社会事件出现和爆发时的时序和结构特征。我们利用符号转移熵的方法对微博的时间序列进行分析,提取出社会系统中地理子块信息传播的有向网络。这种方法成功捕捉到社会集体行为开始形成的系统级的动力。这个框架被五个细致的实证案例分析所验证。具体来说,我们定义了一种在信息传递过程中特定的时间尺度上的变化,这种变化标志着信息驱动的集体现象的开始。进一步地,我们的方法识别出了在社会子单元的有向网络中的有序-无序的转变过程。在明确外源性驱动的情况下,社会集体现象可以表示为内生驱动的结构转换的信息传输网络。这项研究提供的结果,可以帮助定义模型和预测算法来对社会事件开源数据进行分析。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1126/sciadv.1501158<br />
<br />
==在参与社会感知中的自我调节信息共享Self-regulatory information sharing in participatory social sensing==<br />
FromEPJ Data Science 2016 5:14<br />
April 3, 3:00 PM<br />
<br />
By Evangelos Pournaras, Jovan Nikolic, Pablo Velásquez, Marcello Trovati, Nik Bessis and Dirk Helbing<br />
<br />
(Translated by -阎赫, Edited by [[Jake]] )<br />
<br />
''Participation in social sensing applications is challenged by privacy threats. Large-scale access to citizens’ data allow surveillance and discriminatory actions that may result in segregation phenomena in society. On the contrary are the benefits of accurate computing analytics required for more informed decision-making, more effective policies and regulation of techno-socio-economic systems supported by ‘Internet-of Things’ technologies. In contrast to earlier work that either focuses on privacy protection or Big Data analytics, this paper proposes a self-regulatory information sharing system that bridges this gap. This is achieved by modeling information sharing as a supply-demand system run by computational markets. On the supply side lie the citizens that make incentivized but self-determined decisions about the level of information they share. On the demand side stand data aggregators that provide rewards to citizens to receive the required data for accurate analytics. The system is empirically evaluated with two real-world datasets from two application domains: (i) Smart Grids and (ii) mobile phone sensing. Experimental results quantify trade-offs between privacy-preservation, accuracy of analytics and costs from the provided rewards under different experimental settings. Findings show a higher privacy-preservation that depends on the number of participating citizens and the type of data summarized. Moreover, analytics with summarization data tolerate high local errors without a significant influence on the global accuracy. In other words, local errors cancel out. Rewards can be optimized to be fair so that citizens with more significant sharing of information receive higher rewards. All these findings motivate a new paradigm of truly decentralized and ethical data analytics.''<br />
<br />
===Jake修改===<br />
在社会感知的应用中参与性一直受到隐私威胁的挑战。大规模访问公民的数据就使得监控和可能造成社会分离现象的歧视行为得到允许;而它的好处是为更知情的决策提供所需的精确计算与分析,更有效的政策和由物联网技术支持的技术-社会-经济系统的调节。以前的工作要么着眼于隐私保护,要么着眼于大数据分析,本文与这些工作不同,我们提出了一种自我调节的信息共享系统为这个隔阂搭建桥梁。我们通过将信息共享建模为一种计算市场中的供求系统以达到此目的。公民处于供方,他们在所共享的信息层面做出受激励而又自主的决策。数据汇集处于需求方,它们为了精确的分析,为公民接受所需的数据提供报酬。这个系统用来自两个应用领域的两个真实数据集来进行实证地评估:(1)智能网格和(2)手机感应。我们的实验结果可以量化出在不同的实验设定下隐私保护、分析的准确性及提供报酬引发的成本之间的权衡。调查结果显示隐私保护是否高,取决于参与的公民数量和归纳的数据的类型。此外,汇总数据分析能够容忍高度局部错误,对整体准确度没有重大影响。换句话说,局部错误可以被抵消掉。我们可以优化报酬的公平程度以使得能够共享更多重大意义信息的公民会接受更高的报酬。所有这些调查结果激励了一种真正的去中心化的、合乎道德规范的数据分析的范式出现。<br />
<br />
===原文===<br />
参与社会感知的应用受到了隐私威胁的挑战。大规模访问公民的数据容许了监控和导致社会分离现象的歧视行为。与之相反,精确计算分析的好处是需要更多的知情决策,更有效的政策和由物联网技术支持的技术-社会-经济系统的调节。以前的工作或者着眼于隐私保护,或者着眼于大数据分析,本文与以前的研究工作相反,提出为这个隔阂搭建桥梁的自我调节信息共享系统。我们通过建模信息共享达到此目的,正如由计算市场运行的供求机制一样。公民处于供方,他们在所共享的信息层面做出受鼓舞而又自主的决策。数据汇集处于需求方,它们为了精确的分析,为公民接受所需的数据提供报酬。在实际生活中,这个系统用来自两个应用域的两个真实数据集评估:(1)智能网格和(2)手机感应。实验结果量化隐私保护,分析的准确性和从不同实验设施提供的报酬的成本之间的权衡。调查结果显示隐私保护是否高,取决于参与的公民数量和归纳的数据的类型。此外,汇总数据分析容忍高度局部错误,对综合准确度没有重大影响。换句话说,局部错误被抵消了。报酬可以优化到公平的程度,如此,有较多重大意义的信息共享的公民会接受更高的报酬。所有这些调查结果激励一个新的真正的分散和合乎道德规范的模型的出现。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1140/epjds/s13688-016-0074-4<br />
<br />
==一种度量系统复杂性的通用框架(A general framework for measuring system complexity)==<br />
From onlinelibrary.wiley.com <br />
April 3, 12:47 AM<br />
<br />
By Mahmoud Efatmaneshnik and Michael J. Ryan<br />
<br />
(Translated by - 龚力,edited by 傅渥成)<br />
<br />
''In this work, we are motivated by the observation that previous considerations of appropriate complexity measures have not directly addressed the fundamental issue that the complexity of any particular matter or thing has a significant subjective component in which the degree of complexity depends on available frames of reference. Any attempt to remove subjectivity from a suitable measure therefore fails to address a very significant aspect of complexity. Conversely, there has been justifiable apprehension toward purely subjective complexity measures, simply because they are not verifiable if the frame of reference being applied is in itself both complex and subjective. We address this issue by introducing the concept of subjective simplicity—although a justifiable and verifiable value of subjective complexity may be difficult to assign directly, it is possible to identify in a given context what is “simple” and, from that reference, determine subjective complexity as distance from simple. We then propose a generalized complexity measure that is applicable to any domain, and provide some examples of how the framework can be applied to engineered systems.''<br />
<br />
在这项工作中,我们的动机基于此前的系统复杂性度量方法都没有直接解决最本质的问题——任何特定的物质或事物的复杂性具有一个十分显著的主观成分,其复杂性程度取决于观察者采用的参考系。因此,任何试图通过移除系统的主观性来度量其复杂性的方法都不能解决这一非常重要的方面;反之,对于纯粹主观的复杂性度量方法也存在合理的担忧,简单来讲,因为如果参考系本身也是复杂和主观的,那么这种方法必然是不可验证的。我们通过引入主观简单性(subjective simplicity)的概念来解决这个问题——虽然一个合理和可验证的主观复杂性程度值难以直接度量,但是在一个给定的上下文中度量什么是“简单”却是可能的,以此“简单”作为参考,可以将主观复杂性当作到“简单”的距离。然后,我们提出一个广泛的、适用于任何领域的复杂性度量方法,并提供了一些如何将它应用到工程系统中的例子。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1002/cplx.21767<br />
<br />
Remark by fuwocheng:<br />
(1) frames of reference 参考系<br />
<br />
==社交媒体推动社会变革?——似是而非的有效传播(Beyond Viral)==<br />
From cacm.acm.org <br />
April 4, 5:40 PM<br />
<br />
By Manuel Cebrian, Iyad Rahwan, Alex "Sandy" Pentland<br />
<br />
(Translated by - 秦堉朗-ATC-ABM-Canton,edited by 傅渥成)<br />
<br />
''The golden age of social media coincides with a worldwide leadership crisis, manifested by our seeming inability to address any major global issue in recent years.<sup>32</sup> These days, no one—be they a charismatic leader or a nameless crowd—seems to be able to make issues popular for long enough to mobilize society into action. As a result of this leadership vacuum, social progress of all sorts seems to have become stymied and frozen. How can this happen precisely in a time when social media, praised as the ultimate tool to raise collective awareness and mobilize society, has reached maturity and widespread use? Here, we argue the coexistence of social media technologies with 'The End of Power'<sup>18</sup> is anything but a coincidence, presenting the first techno-social paradox of the 21st century.''<br><br />
''In recent years, we have witnessed social media playing a major role in social mobilization events of historic proportions, such as the Arab Spring, the Occupy Wall Street movement, Ukraine's Euromaidan, and the chaos generated by the England Riots and Boston Marathon bombing manhunt. There has been substantial emphasis on the role of digital social media platforms, particularly Facebook and Twitter, as the facilitators of these mobilizations. Data availability has made it possible, for the first time, to observe the evolution of these events in detail.<sup>10,11,13,33</sup> Analysis of these events makes it clear that political activists find it difficult to use social media to create mass mobilization; and even when they succeed it is difficult to sustain the focus of the protest until it is able to mobilize politicians, institutions, and society at large. As a result, most of these events burst upon the scene, occupy our attention for a few days, and then fade into oblivion with nothing substantial having been accomplished. Given all we have learned about social mobilization, why isn't social media a more reliable channel for constructive social change?''<br><br />
<br />
近年来,在解决重大全球性问题上我们似乎依然力不从心,与此同时,社交媒体的黄金时代正与全球领导力危机一同到来。现阶段,似乎没有人——无论是一个充满魅力的领袖或是一帮籍籍无名的大众——能够让这些全球性问题受到足够多的关注并推动整个社会为之付出行动。由于这种领导力的缺失,各种各样的社会进程也似乎停滞不前。这些现象归根究底是如何在社交媒体——已经成熟发展、广泛应用,并被人们称赞为唤醒社会集体意识、动员社会力量的终极工具——大行其道的时代发生的呢?在此笔者认为,社交媒体技术的发展与“权利的终结”<sup>18</sup>现象共同存在绝非巧合,反而展现了21世纪的首要悖论:技术进步与社会发展的背道而驰。<br><br />
近年来,由社交媒体主导的社会运动数量占到了一个历史性的高比例,我们见证了这一时代。在诸如阿拉伯之春、占领华尔街运动、乌克兰亲欧示威,以及由于英国骚乱和波士顿马拉松爆炸嫌犯追捕所带来的混乱等社会运动中,社交媒体都在社会运动中起到了举足轻重的作用。现在已经有大量的关注度集中在数字社交媒体平台所扮演的角色上,特别是Facebook和Twitter——这些社会运动的推波助澜者们。容易被获取的数据为人们首次细致入微地观察这些事件的演化过程提供了可能。<sup>10,11,13,33</sup>通过对这些事件的分析,社会活动家们更加清楚地发现,经由社交媒体来推动大规模的社会运动是难以实现的,就算他们能够掀起一场运动,也很难去维持运动的焦点,直到这个运动能够大面积地影响政治家、政府机构和整个社会。结果,大部分的这类运动都在特定的场景爆发,在一段时间内吸引了我们的眼球,然后就在毫无长久建树的遗憾和人们的淡忘中不了了之。根据我们对社会运动的所有这些了解,为什么社交媒体不能成为通向有建设性的社会变革的桥梁?<br><br />
<br />
'''原文链接:'''http://dx.doi.org/10.1145/2818992<br />
<br />
Remark by fuwocheng:<br />
翻译得非常好。<br />
一些语法的细节问题,如句子 "and the chaos generated by the England Riots and Boston Marathon bombing manhunt",注意到这里出现了两个 and,因此应该理解为「由于英国骚乱和波士顿马拉松爆炸嫌犯追捕所带来的混乱」。<br />
<br />
==多层随机分块模型揭示复杂网络的多层结构(Multilayer Stochastic Block Models Reveal the Multilayer Structure of Complex Networks)==<br />
From Phys. Rev. X 6, 011036 – Published 31 March 2016<br />
April 5, 5:46 PM<br />
<br />
By Toni Vallès-Català, Francesco A. Massucci, Roger Guimerà, and Marta Sales-Pardo<br />
<br />
(Translated by -dan,edited by 傅渥成)<br />
<br />
''In complex systems, the network of interactions we observe between systems components is the aggregate of the interactions that occur through different mechanisms or layers. Recent studies reveal that the existence of multiple interaction layers can have a dramatic impact in the dynamical processes occurring on these systems. However, these studies assume that the interactions between systems components in each one of the layers are known, while typically for real-world systems we do not have that information. Here, we address the issue of uncovering the different interaction layers from aggregate data by introducing multilayer stochastic block models (SBMs), a generalization of single-layer SBMs that considers different mechanisms of layer aggregation. First, we find the complete probabilistic solution to the problem of finding the optimal multilayer SBM for a given aggregate-observed network. Because this solution is computationally intractable, we propose an approximation that enables us to verify that multilayer SBMs are more predictive of network structure in real-world complex systems.''<br />
<br />
<br />
在复杂系统中,我们观察到的系统各部分之间的相互作用网络实际上是通过不同的机制产生或者发生在不同的层次之间的多种相互作用的聚合。最新的研究表明,多个交互层次的存在能够显著地影响发生在复杂系统上的动态过程。这些研究假设每个层次以内,系统各部分的相互作用是已知的,然而,通常我们并不能得到真实世界里复杂系统上的这些相互作用信息。在本文中,我们为了从聚合的网络数据(即观察到的数据)中发掘出不同的相互作用层次,推广了单层的随机分块模型,引入了多层随机分块模型,把层次聚合的不同机制考虑在内。对给定的观察到的聚合网络数据,我们首先找出最优的多层随机分块模型问题的完全概率解。但由于这个解的计算非常复杂,我们提出一种近似解,能够帮助我们验证:多层随机分块模型能够预测真实世界里的复杂系统的网络结构。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1103/PhysRevX.6.011036<br />
<br />
==实时情境中社会习俗的形成(The Formation of Social Conventions in Real-Time Environments)==<br />
<br />
From PLoS ONE 11(3): e0151670.<br />
April 6, 12:25 AM<br />
<br />
By Hawkins RXD, Goldstone RL,Hawkins RXD<br />
<br />
(Translated by 阿勺)<br />
<br />
''Why are some behaviors governed by strong social conventions while others are not? We experimentally investigate two factors contributing to the formation of conventions in a game of impure coordination: the continuity of interaction within each round of play (simultaneous vs. real-time) and the stakes of the interaction (high vs. low differences between payoffs). To maximize efficiency and fairness in this game, players must coordinate on one of two equally advantageous equilibria. In agreement with other studies manipulating continuity of interaction, we find that players who were allowed to interact continuously within rounds achieved outcomes with greater efficiency and fairness than players who were forced to make simultaneous decisions. However, the stability of equilibria in the real-time condition varied systematically and dramatically with stakes: players converged on more stable patterns of behavior when stakes are high. To account for this result, we present a novel analysis of the dynamics of continuous interaction and signaling within rounds. We discuss this previously unconsidered interaction between within-trial and across-trial dynamics as a form of social canalization. When stakes are low in a real-time environment, players can satisfactorily coordinate ‘on the fly’, but when stakes are high there is increased pressure to establish and adhere to shared expectations that persist across rounds.''<br />
<br />
为什么有些行为受根深蒂固的社会习俗约束,而有些不受呢?我们通过实验研究了非协作博弈中形成习俗的两个因素:每轮博弈互动的连续性(同时vs实时)和互动时的风险性(高vs低回报之间的差异)。为最大限度地提升博弈的效率和公平性,玩家必须在两个同样具有挑战性的均衡点间选择其一。与其他控制互动连续性的研究相同的是,我们发现那些允许在比赛回合内持续互动的玩家,相比那些被迫同时做决定的玩家,具有更高的效率和公平性。然而在实时情境中,均衡的稳定性随赌注系统性的变化而产生了戏剧性的差异:当赌注高时,玩家行为更稳定。为了解释这个结果,我们对每轮博弈中连续的互动动力学和信号动力学提出了一种全新分析。我们研究了前人的讨论中所没有考虑过的一种动力学,它反映了一次实验以内或者多次实验间的相互作用,这种相互作用是社会渠道(social canalization,编者注:追随社会主流风气,进一步导致社会集体态度的形成。)的一种形式。当实时情境中的赌注较低,玩家能协同合作,但当赌注增加,玩家建立和倾向于分享经验的压力就越大。<br />
<br />
Remark by 傅渥成:<br />
要注意翻译的时候一些最最关键的词不能漏掉,这篇文章的一个关键就是「实验」,experimentally,只看到 investigate,把这句话翻译成调研,就把意思完全弄错了。还有一些低级错误,如 game 是「博弈」, signaling within rounds,round就是博弈中的「轮」。<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1371/journal.pone.0151670<br />
<br />
==理解群体动力学与团队的成功(Understanding the group dynamics and success of teams)==<br />
From Royal Society Open Science<br />
April 7, 6:57 PM<br />
<br />
By Michael Klug, James P. Bagrow<br />
<br />
(Translated by -猪哥, edited by 傅渥成)<br />
<br />
''Complex problems often require coordinated group effort and can consume significant resources, yet our understanding of how teams form and succeed has been limited by a lack of large-scale, quantitative data. We analyse activity traces and success levels for approximately 150, 000 self-organized, online team projects. While larger teams tend to be more successful, workload is highly focused across the team, with only a few members performing most work. We find that highly successful teams are significantly more focused than average teams of the same size, that their members have worked on more diverse sets of projects, and the members of highly successful teams are more likely to be core members or ‘leads’ of other teams. The relations between team success and size, focus and especially team experience cannot be explained by confounding factors such as team age, external contributions from non-team members, nor by group mechanisms such as social loafing. Taken together, these features point to organizational principles that may maximize the success of collaborative endeavours.'''<br />
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复杂的问题往往需要团队努力协调解决,并且会消耗大量资源,然而我们对团队如何形成、如何成功的理解却因缺乏大规模的、定量的数据而受到限制。我们对大约150, 000个自组织在线团队项目的活动轨迹和成功水平进行了分析。虽然较大的团队往往会更成功,但工作量在团队中的分布是高度集中的,即只是由少数成员进行了最多的工作。我们发现非常成功的团队的这种集中程度显著高于具有相同规模的普通团队,他们的成员会参与更多样化的项目,并且这些高度成功团体的成员更可能成为其他团队的核心或“领导”。团队的成功和它的规模、关注点、尤其是团队经验之间的关系不能用易混淆的因素来解释,比如团队年龄,来自非团队成员的外部贡献等,也不能用群体机制比如社会惰化来解释。总之,这些特点所指向的组织原则可能会让组织在尽力配合下取得最大的成功。<br />
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'''原文链接:'''http://dx.doi.org/10.1098/rsos.160007<br />
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Remark by 傅渥成:翻译得非常好。<br />
<br />
==对企业所有权的透明度和黑金而言,巴拿马文件意味着什么?(What the Panama Papers Mean for Transparency and ‘Dark Money’)==<br />
From knowledge.wharton.upenn.edu<br />
April 8, 7:46 PM<br />
<br />
By Aldo Mascareño, Eric Goles andGonzalo A. Ruz<br />
<br />
(Translated by -jeffersonchou)<br />
<br />
''Last Sunday, the International Consortium of Investigative Journalists (ICIJ) published a massive leak of some 11.5 million documents covering nearly 40 years, from 1977 through 2015, that showed how world leaders, politicians and businesses hide and launder their money, evade taxes and finance arms and drug deals. The source of the leak is a little-known but powerful law firm in Panama called Mossack Fonseca, which is one of the top creators of shell companies and corporate structures that can be used to hide ownership of assets. The leaked data provide a day-to-day, decade-by-decade look at how dark money flows through the global financial system, breeding crime and stripping national treasuries of tax revenues.''<br />
<br />
''The ICIJ published these documents after a year long investigation along with German newspaper Süddeutsche Zeitung and more than 100 other news organizations. The leaks which is just one part and the beginning of a wider scandal, reveal the offshore holdings of 140 politicians and public officials around the world, including a dozen current and former world leaders. The ICIJ has said it would release the full list of companies and people linked to it in early May.''<br />
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''The Panama Papers, as the leaked documents are called, exposes just one firm in a larger industry. The trouble is it is legal to set these anonymous companies up in various jurisdictions around the world. The Panama Papers offer a rare opportunity to regulators in the U.K., the U.S. and other countries to bring about greater transparency in the ownership of the firms,to tighten their regulations to prevent abuse by the companies they incorporate.''<br />
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''A positive outcome of the Panama Papers scandal is that it brings this into the public realm, making it possible for citizens to see the effects of these companies, to see policies that are enforced in their countries that enable these types of activities to happen and to engage with their governments to take action to fix it. The ICIJ has make it easy for prosecution, and governments need to start following their lead.''<br />
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上周日,国际记者调查联盟(ICIJ)公布公布了约1150万份文件,这些大规模泄漏的文件,揭露了从1977年到2015年的40年间,世界各国领导人、政治家和商人,是如何隐瞒收入、洗钱、逃税和资助军火和毒品交易的。泄漏的文件来源于巴拿马一个鲜为人知但很有影响力的律师事务所——莫萨克·丰塞卡律师事务所 (Mossack Fonseca),它是一家通过创造空壳公司,设计企业架构,帮助客户隐瞒资产所有权的顶尖服务供应商。这些泄露的数据提供了一个逐天、逐年的视角,来观察黑暗金钱是如何流入全球金融体系,滋生犯罪和偷逃国库收入的。<br />
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国际记者调查联盟与德国报纸《南德意志报》(Süddeutsche Zeitung)等一百多家新闻机构合作,在进行一年的调查后,公布了这批文件。这些文件披露的只是更大丑闻的冰山一角,它们暴露了世界各地的140位政治家和政府官员,包括十几位现任和前任世界领导人所拥有的离岸控股公司。国际记者调查联盟称,他们会在五月上旬公布相关公司和人员的完整名单。<br />
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这批被称为“巴拿马文件”的泄露文件,仅仅揭开了这个巨大产业中的冰山一角。问题在于,在全球各地的司法系统中,建立这些匿名公司是合法的。巴拿马文件的泄密为英国、美国和其他国家的监管机构,提供了难得的机会,要求增加企业所有权信息的透明度,并收紧相关规定以防止不法分子滥用。<br />
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巴拿马文件丑闻的正面效应是,它把空壳公司洗钱产业的黑幕带到公众视野之内,从而让广大民众看到这些空壳公司的影响,看到他们国家的某些政策导致此类活动发生,从而积极与政府交流,推动政府采取行动来解决相关问题。国际记者调查联盟的泄密也使后续的司法调查变得更加容易,政府需要跟随他们采取进一步的行动。<br />
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'''原文链接:'''http://knowledge.wharton.upenn.edu/article/confalon-nichols-panama-papers/<br />
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edited by 傅渥成<br />
<br />
==持续减少跨性别歧视:一场关于逐户拉票的田野实验(Durably reducing transphobia: A field experiment on door-to-door canvassing )==<br />
Science 08 Apr 2016: Vol. 352, Issue 6282, pp. 220-224<br />
April 8, 10:10 PM<br />
<br />
BY David Broockman, Joshua Kalla<br />
<br />
(Translated by -北宁)<br />
<br />
现有的研究表明人类群体间的偏见根深蒂固,需要通过强烈地干预才能减少。现在,我们通过实验证明,仅通过约10分钟的鼓励积极采取他人视角来看问题的谈话就能明显降低偏见至少3个月。我们通过在南佛罗里达进行的一场旨在减少反对变性人偏见的的逐户拉票(door-to-door canvassing)活动来说明这种潜力。尽管社会对同性恋的偏见在下降,但是跨性别的歧视依然普遍存在。对于此次干预活动,我们安排56个游说人在501个选民的家门口,挨家挨户地进行积极鼓励的谈话。随机实验发现,进行的谈话能使得对跨性别者的歧视大大下降,这一下降的比例要比美国在1998至2012年间同性恋歧视者的下降率要更为显著。这些影响可以持续3个月以上,且不管游说人是变性人和非变性人都有效。即使当将选民暴露在相反论点的情况下,此次干预活动还是增加了选民对一项反歧视法律的支持。<br />
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Existing research depicts intergroup prejudices as deeply ingrained, requiring intense intervention to lastingly reduce. Here, we show that a single approximately 10-minute conversation encouraging actively taking the perspective of others can markedly reduce prejudice for at least 3 months. We illustrate this potential with a door-to-door canvassing intervention in South Florida targeting antitransgender prejudice. Despite declines in homophobia, transphobia remains pervasive. For the intervention, 56 canvassers went door to door encouraging active perspective-taking with 501 voters at voters’ doorsteps. A randomized trial found that these conversations substantially reduced transphobia, with decreases greater than Americans’ average decrease in homophobia from 1998 to 2012. These effects persisted for 3 months, and both transgender and nontransgender canvassers were effective. The intervention also increased support for a nondiscrimination law, even after exposing voters to counterarguments.<br />
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原文链接:http://science.sciencemag.org/content/352/6282/220<br />
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edited by 傅渥成<br />
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==为什么自然钟情于正六边形? (Why Nature Prefers Hexagons) ==<br />
Nautilus<br />
April 9, 8:04 PM<br />
<br />
BY PHILIP BALL<br />
<br />
(Translated by -刘清晴、陈开壮、李宇峰)<br />
<br />
(以下由李宇峰翻译)<br />
<br />
How do bees do it? The honeycombs in which they store their amber nectar are marvels of precision engineering, an array of prism-shaped cells with a perfectly hexagonal cross-section. The wax walls are made with a very precise thickness, the cells are gently tilted from the horizontal to prevent the viscous honey from running out, and the entire comb is aligned with the Earth’s magnetic field. Yet this structure is made without any blueprint or foresight, by many bees working simultaneously and somehow coordinating their efforts to avoid mismatched cells.<br />
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蜜蜂怎么做到的?它们用来储存金黄色花蜜的蜂巢,那一组组正六边形的格子,实在是精密工程中的奇迹。蜡筑的巢壁有着十分严格的厚度,格子相对水平面倾斜以防止黏黏的蜜流出,整个蜂巢还与地球磁场方向对齐。不过,这项工程的完成没有任何蓝图与规划,仅仅依靠无数的蜜蜂同时工作,并以某种奇特的方式协调着它们的努力从而避免搭出不合格的巢格。<br />
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The ancient Greek philosopher Pappus of Alexandria thought that the bees must be endowed with “a certain geometrical forethought.” And who could have given them this wisdom, but God? According to William Kirby in 1852, bees are “Heaven-instructed mathematicians.” Charles Darwin wasn’t so sure, and he conducted experiments to establish whether bees are able to build perfect honeycombs using nothing but evolved and inherited instincts, as his theory of evolution would imply.<br />
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古希腊哲学家帕普斯觉得蜜蜂一定有着“某种特定的几何预见”。可又是谁给它们赋予这般智慧呢,难不成是上帝?按照威廉卡比在1852年的说法,蜜蜂是天生的数学家。查尔斯达尔文对此是怀疑的,于是他设置了实验来弄清楚蜜蜂是否真的能够仅仅依靠演化遗传来的本能建筑出如此完美的蜂巢,正如他的遗传理论所暗示的那样。<br />
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Why hexagons, though? It’s a simple matter of geometry. If you want to pack together cells that are identical in shape and size so that they fill all of a flat plane, only three regular shapes (with all sides and angles identical) will work: equilateral triangles, squares, and hexagons. Of these, hexagonal cells require the least total length of wall, compared with triangles or squares of the same area. So it makes sense that bees would choose hexagons, since making wax costs them energy, and they will want to use up as little as possible—just as builders might want to save on the cost of bricks. This was understood in the 18th century, and Darwin declared that the hexagonal honeycomb is “absolutely perfect in economizing labor and wax.”<br />
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不过,蜂巢格为什么是正六边形的呢?这是一个简单的几何问题。当你想要用同样形状和大小的小块来铺满整个平面时,你会发现只有三种形状能满足要求(正三角形、正方形,还有就是正六边形)而在这当中,正六边形的结构能用最少的边围出正三角、正方形能做到的同样大的面积。蜜蜂理所当然会选用正六边形,因为产生蜂蜡是要消耗它们体力的,它们自然想尽量节省着用——正如我们的建筑工人会想怎么节省建筑的砖瓦。人们在18世纪就已经了解到这一点,而达尔文宣称这正六边形的结构是“绝对有利于节省蜜蜂的体力和蜂蜡”的。<br />
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Darwin thought that natural selection had endowed bees with instincts for making these wax chambers, which had the advantage of requiring less energy and time than those with other shapes. But even though bees do seem to possess specialized abilities to measure angles and wall thickness, not everyone agrees about how much they have to rely on them. That’s because making hexagonal arrays of cells is something that nature does anyway.<br />
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达尔文认为是自然选择赋予了蜜蜂搭筑这样的蜡房子的本能,因为它那比其他形状需要更少的能量与时间的优势。纵然蜜蜂似乎显现出相当专业的测量夹角和巢璧厚度的能力,但不是所有人都认同它们自身有着这么大的能耐。这时应为,创造正六边形这件事,自然正以其他方式在做。<br />
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If you blow a layer of bubbles on the surface of water—a so-called “bubble raft”—the bubbles become hexagonal, or almost so. You’ll never find a raft of square bubbles: If four bubble walls come together, they instantly rearrange into three-wall junctions with more or less equal angles of 120 degrees between them, like the center of the Mercedes-Benz symbol.<br />
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如果你在水面吹出一层泡沫——这又被叫做“泡筏”——这些泡沫会变成正六边形或者近似的形状。你不会找到一漂正方形的泡泡:如果四个泡泡挤在一块,它们会很快重排三个球的连接点,内壁或大或小地接近120度,就像奔驰汽车的商标中间那块一样。<br />
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Evidently there are no agents shaping these rafts as bees do with their combs. All that’s guiding the pattern are the laws of physics. Those laws evidently have definite preferences, such as the bias toward three-way junctions of bubble walls. The same is true of more complicated foams. If you pile up bubbles in three dimensions by blowing through a straw into a bowl of soapy water you’ll see that when bubble walls meet at a vertex, it’s always a four-way union with angles between the intersecting films roughly equal to about 109 degrees—an angle related to the four-faceted geometric tetrahedron.<br />
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显然地没有谁在一手捏造这些泡筏,一如蜜蜂对与它们的蜂巢。是物理的规律,塑造出了这般的模型。这些规则显然有特定的偏好,比如偏心泡泡间三向连接。当泡沫变得复杂时,这点同样成立。如果你往一瓶子肥皂水中用吸管吹气,堆起一堆三维中的泡沫,你会看见当有泡泡在一个顶点相聚时,它们永远是一种四向连接的结构,他们的相交膜之间的夹角都近似于109度——这一角度与正四面体的内角相关。<br />
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(以下由陈开壮翻译)<br />
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What determines these rules of soap-film junctions and bubble shapes? Nature is even more concerned about economy than the bees are. Bubbles and soap films are made of water (with a skin of soap molecules) and surface tension pulls at the liquid surface to give it as small an area as possible. That’s why raindrops are spherical (more or less) as they fall: A sphere has less surface area than any other shape with the same volume. On a waxy leaf, droplets of water retract into little beads for the same reason.<br />
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什么决定着肥皂泡薄膜连接和气泡形状的规则?大自然甚至比蜜蜂更加关注经济性。气泡和肥皂泡薄膜是由水构成的(一层肥皂泡分子),其表面张力作用于液体表面从而获得尽可能小的表面积。这就是为什么雨滴(或多或少)在下落时是球状的:一个球体在相同体积下比其他任何形状具有的表面积更小。由于同样的原因,在含蜡质层的叶子上散落的水滴汇集成小水珠。<br />
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This surface tension explains the patterns of bubble rafts and foams. The foam will seek to find the structure that has the lowest total surface tension, which means the least area of soap-film wall. But the configuration of bubble walls also has to be mechanically stable: The tugs in different directions at a junction have to balance perfectly, just as the forces must be balanced in the walls of a cathedral if the building is going to stand up. The three-way junction in a bubble raft, and the four-way junctions in foam, are the configurations that achieve this balance.<br />
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这种表面张力解释了气泡筏(bubble rafts)和泡沫的模式。泡沫会努力实现拥有最小表面张力的结构,这意味着肥皂泡薄膜墙面积最小。然而气泡墙(bubble wall)的架构也必须在力学上是稳定的:各个方向的拉力在结合部位必须完美地平衡,正如一所大教堂墙面的全部受力必须保持平衡一样,如果该建筑要矗立起来。气泡筏(bubble rafts)中的三向连接(three-way junction)以及泡沫中的四向连接(four-way junctions)就是实现这种平衡的架构。<br />
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But those who think (as some do) that the honeycomb is just a solidified bubble raft of soft wax might have trouble explaining how the same hexagonal array of cells is found in the nests of paper wasps, who build not with wax but with chewed-up wads of fibrous wood and plant stem, from which they make a kind of paper. Not only can surface tension have little effect here, but it also seems clear that different types of wasp have different inherited instincts for their architectural designs, which can vary significantly from one species to another.<br />
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然而,那些认为(有人这样想)蜂巢只是软蜡固化的气泡筏(bubble rafts)的人们可能无法解释同样的六边形单元何以在纸黄蜂的蜂巢中也有发现,它们不是用蜡构筑蜂巢,而是用嚼碎的纤维木絮和植物茎絮,用这些东西可以造出一种纸来。这里不只是没有表面张力的作用,而且似乎显而易见的是不同种类的黄蜂遗传了它们各自不同的“建筑设计”天性,这种“建筑设计”由一个物种明显地变化为另一个。<br />
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Although the geometry of soap-film junctions is dictated by this interplay of mechanical forces, it doesn’t tell us what the shape of the foam will be. A typical foam contains polyhedral cells of many different shapes and sizes. Look closely and you’ll see that their edges are rarely perfectly straight; they’re a little curved. That’s because the pressure of the gas inside a cell or bubble gets bigger as the bubble gets smaller, so the wall of a small bubble next to a larger one will bulge outward slightly. What’s more, some facets have five sides, some six, and some just four or even three. With a little bending of the walls, all of these shapes can acquire four-way junctions close to the “tetrahedral” arrangement needed for mechanical stability. So there’s a fair bit of flexibility (literally) in the shapes of the cells. Foams, while subject to geometrical rules, are rather disorderly.<br />
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尽管肥皂泡薄膜连接的几何图形是用物理上力的相互作用表述的,但它没有告诉我们泡沫的形状将会是什么。典型的泡沫包括了许多不同形状和尺寸的多面体单元。近距离观察你就会发现它们的边缘很少是完全直的,它们有一点弯曲。那是因为细胞和气泡中气体的压力在气泡变小时变得更大了,因此靠近较大气泡的小气泡墙朝外轻微凸起。此外,有些面有五边、有的六边,甚至有的只有四边或者三边。只要气泡墙(bubble wall)发生小小的变形,所有这些形状就可以变成接近力学稳定性所需“四面体”结构的四向连接(four-way junctions)。所以,在这样的单元形状中,这真的有点柔性(这种柔性的确对应于物理学上的柔性)。泡沫,在遵循几何规则时,是相当不规则的。<br />
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Suppose that you could make a “perfect” foam in which all the bubbles are the same size. What then is the ideal cell shape that makes the total bubble wall area as small as possible while satisfying the demands for the angles at the junctions? That has been debated for many years, and for a long time it was thought that the ideal cell shape was a 14-sided polyhedron with square and hexagonal faces. But in 1993 a slightly more economical—although less orderly—structure was discovered, consisting of a repeating group of eight different cell shapes. This more complex pattern was used as the inspiration for the foam-like design of the swimming stadium of the 2008 Olympic Games in Beijing.<br />
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设想你能做一个“理想”泡沫,泡沫中所有的气泡都具有相同的尺寸,那么在连接处满足所有角度要求使总的气泡墙(bubble wall)面积尽可能小的理想单元形状是什么?这个问题已经争论了很多年了,而且在相当长一段时间内被认为理想的单元形状是一个同时具有矩形面和六边形面的14边多面体。可在1993年,一种稍微更加经济的——尽管不是很有序——结构被发现了,该结构由包含八种不同单元形状的重复团(repeating group)构成,这种更复杂的模式被用作2008年北京奥运会游泳场馆气泡状设计的灵感。<br />
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The rules of cell shapes in foams also control some of the patterns seen in living cells. Not only does a fly’s compound eye show the same hexagonal packing of facets as a bubble raft, but the light-sensitive cells within each of the individual lenses are also clustered in groups of four that look just like soap bubbles. In mutant flies with more than four of these cells per cluster, the arrangements are also more or less identical to those that bubbles would adopt.<br />
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气泡中单元形状的规则也控制着在活细胞中看到的某些模式。不只是苍蝇的复眼展示出像气泡筏(bubble rafts)一样的一组六边形面,而且在每个晶状体中的感官细胞也以4个1组的方式如肥皂泡沫般地聚集在一起。<br />
<br />
(以下由刘清晴翻译)<br />
<br />
Because of surface tension, a soap film stretching across a loop of wire is pulled flat like the springy membrane of a trampoline. If the wire frame is bent, the film also bends with an elegant contour that automatically tells you the most economical way, in terms of material, to cover over the space enclosed by the frame. That can show an architect how to make a roof for a complicated structure using the least amount of material. However, it’s as much because of the beauty and elegance of these so-called “minimal surfaces,” as because of their economy that architects such as Frei Otto have used them in their buildings.<br />
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由于表面张力,线圈中间的肥皂泡薄膜会像蹦床那有弹性的床面一样被拉成平面。如果将线圈弯曲,那么肥皂泡薄膜会随之弯成一个优雅的轮廓,自动告诉你最经济的做法。用材料学术语来说,就是遮没(cover over)被线圈所包围的空间。这可以让建筑师知道该如何使用最少的材料给一个结构复杂的建筑造一个屋顶。无论如何,由于这些被称为“最小曲面(minimal surfaces)”的美丽优雅,以及它们的经济性,弗雷·奥托(Frei Otto)等建筑师已经将它们应用在了自己的建筑中。<br />
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These surfaces minimize not only their surface area, but also their total curvature. The tighter the bend, the greater the curvature. Curvature can be positive (bulges) or negative (dips, depressions, and saddles). A curved surface can therefore have zero mean curvature so long as the positives and negatives cancel each other out.<br />
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这些曲面的最小化不仅体现在它们的表面积上,还体现在总曲率上。弯曲越大,曲率就越大。曲率可以是正数(对于凸的结构),也可以是负数(对于倾斜、凹陷和马鞍状结构)。于是,当正负互相抵消时,就会出现曲面的平均曲率为0的情况。<br />
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So a sheet can be full of curvature and yet have very little or even no mean curvature. Such a minimally curved surface can divide up space into an orderly labyrinth of passageways and channels—a network. These are called periodic minimal surfaces. (Periodic just means a structure that repeats identically again and again, or in other words, a regular pattern.) When such patterns were discovered in the 19th century, they seemed to be just a mathematical curiosity. But now we know that nature makes use of them.<br />
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所以一个片状结构可以由各种曲面构成,且其平均曲率非常小甚至为0。这样一个具有最小曲率的曲面可以将空间分成一个有序的,由孔道构成的迷宫——形成一个网络。这被称作周期性最小曲面。(周期性仅仅用来描述同一种结构一次又一次重复出现的情况,换句话说,这是一种有规律的模式。)当这些模式在19世纪被发现的时候,它们似乎仅仅是一种数学游戏。但现在我们知道,大自然在应用这些模式。<br />
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The cells of many different types of organisms, from plants to lampreys to rats, contain membranes with microscopic structures like this. No one knows what they are for, but they are so widespread that it’s fair to assume they have some sort of useful role. Perhaps they isolate one biochemical process from another, avoiding crosstalk and interference. Or maybe they are just an efficient way of creating lots of “work surface,” since many biochemical processes take place at the surface of membranes, where enzymes and other active molecules may be embedded. Whatever its function, you don’t need complicated genetic instructions to create such a labyrinth: The laws of physics will do it for you.<br />
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许多不同的生物体,从植物到七鳃鳗到鼠,这样的微观结构存在于构成它们细胞的膜结构中。没人知道为什么会有这样的微观结构,但是它们如此广泛的存在着,使我们不由得猜测它们一定在扮演着某种重要的角色。也许这些结构把一个个生化反应彼此分隔开来,避免它们发生交互,相互干扰。或者,也许这只是一种高效的方式,创造出了很多“工作面”,因为很多生化反应都发生在膜结构表面,这些膜中镶嵌着酶和其他活性分子。无论它的功能是什么,你都不需要借助复杂的基因指令来创造这样一个迷宫:物理定律会帮助你把它实现。<br />
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Some butterflies, such as the European green hairstreak and the emerald-patched cattleheart, have wing scales containing an orderly labyrinth of the tough material called chitin, shaped like a particular periodic minimal surface called the gyroid. Interference between light waves bouncing regular arrays of ridges and other structures on the wing-scale surface causes some wavelengths—that is, some colors—to disappear while others reinforce each other. So here the patterns offer a means of producing animal color.<br />
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一些蝴蝶,比如Europe green hairstreak和emerald-patched cattleheart,它们翅膀鳞片中含有由一种叫做几丁质的坚韧物质整齐排列而成的迷宫状结构,类似于一种被称作螺旋二十四面体的周期性最小曲面。光照射到翅膀鳞片表面这些有序的结构和其他结构上,发生反射并产生干涉,使某些波长的光——也就是颜色——消失,同时另一些波长的光增强。于是,这些微观结构有了一个作用,就是使蝴蝶翅膀呈现出五彩斑斓的色彩。<br />
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The skeleton of the sea urchin Cidaris rugosa is a porous mesh with the shape of another kind of periodic minimal surface. It’s actually an exoskeleton, sitting outside the organism’s soft tissue, a protective shell that sprouts dangerous-looking spines made from the same mineral as chalk and marble. The open lattice structure means that the material is strong without being too heavy, rather like the metal foams used for building aircraft.<br />
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Cidaris rugosa海胆的骨骼是一种由另外一种周期性最小曲面构成的多孔的多边形网状结构。实际上,这是外骨骼,存在于生物体软组织的外部,形成一个外壳来保护生物体。这外壳上伸出一些看上去很危险的突起,这些突起是由与粉笔和大理石同样的矿物质构成的。这种开放的晶格结构意味着材料坚韧但并不沉重,就像用于制造航空飞行器的金属泡沫一样。<br />
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To make orderly networks from hard, stiff mineral, these organisms apparently make a mold from soft, flexible membranes and then crystallize the hard material inside one of the interpenetrating networks. Other creatures may cast orderly mineral foams this way for more sophisticated purposes. Because of the way that light bounces off the elements of the patterned structure, such trellises can act rather like mirrors to confine and guide light. A honeycomb arrangement of hollow microscopic channels within the chitin spines of a peculiar marine worm known as the sea mouse turns these hair-like structures into natural optical fibers that can channel light, making the creature change from red to bluish green depending on the direction of the illumination. This color change might serve to deter predators.<br />
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为了把坚实而僵硬的矿物质变成有序的网状结构,这些生物体似乎首先用柔软而灵活的膜结构做了个模子,然后使得坚硬的材料在一个个相互连通的网格中结晶。其他生物会铸造有序的矿物质泡沫来实现更加复杂的目标。由于光可以被模式化的微观结构反射,那些网格状的结构可以像镜子一样对光的传播进行限制和引导。海鼠(sea mouse)是一种独特的海生蠕虫,它体表的几丁质突起具有蜂巢状排列的微管结构。海鼠可以将这些毛发状的结构变成天然的光纤来传导光,通过改变光入射的方向可以使自己由红色变成蓝绿色。这种改变颜色的举措可能是为了防御捕食者。<br />
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This principle of using soft tissues and membranes as molds for forming patterned mineral exoskeletons is widely used in the sea. Some sponges have exoskeletons made of bars of mineral linked like climbing frames, which look remarkably similar to the patterns formed by the edges and junctions of soap films in foam—no coincidence, if surface tension dictates the architecture.<br />
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这种使用柔软的组织和膜作为模子来构建模式化的矿物质外骨骼的原则在海洋生物中被广泛采用。一些的海绵的外骨骼由以攀爬架状连接的棒状矿物质结晶构成,看上去与肥皂泡的结构惊人的相似——不是巧合,是表面张力造就了这样的结构。<br />
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Such processes, known as biomineralization, generate spectacular results in marine organisms called radiolarians and diatoms. Some of these have delicately patterned exoskeletons made from a mesh of mineral hexagons and pentagons: You might call them the honeycombs of the sea. When the German biologist (and talented artist) Ernst Haeckel first saw their shapes in a microscope in the late 19th century, he made them the star attraction of a portfolio of drawings called Art Forms in Nature, which were very influential among artists of the early 20th century and still inspire admiration today. To Haeckel, they seemed to offer evidence of a fundamental creativity and artistry in the natural world—a preference for order and pattern built into the very laws of nature. Even if we don’t subscribe to that notion now, there’s something in Haeckel’s conviction that patterns are an irrepressible impulse of the natural world—one that we have every right to find beautiful.<br />
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这种被称为生物矿物化的过程在放射虫和矽藻这些海洋生物中产生了惊人的效果。它们中的某些种类具有精致的网格状矿物质外骨骼,由六边形和五边形组成:你或许可以称之为海洋中的蜂巢。19世纪末,当德国生物学家(同时也是一个有才华的艺术家)Ernst Haeckel第一次用显微镜看到它们的形态的时候,他将它们画下来并集结成册,名为《自然界的艺术形式(art forms in nature)》,使它们有了明星般的吸引力。这本画集在20世纪初的艺术家中很有影响力,直到今天仍然广受赞誉。对于Haeckel来说,它们似乎为自然界以创造性和艺术性为本的观点提供了证据——对于秩序和模式的偏好是内置在基本自然法则中的。虽然我们现在并不赞同这个观点,但是正如Haeckel所确信的那样,模式的形成是自然界抑制不住的冲动,我们完全有权利去探寻美。<br />
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原文链接:http://nautil.us/issue/35/boundaries/why-nature-prefers-hexagons<br />
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edited by 傅渥成<br />
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==为什么国家卫生研究院(NIH)应该用抽签替换同行评审(Why the National Institutes of Health Should Replace Peer Review With a Lottery)==<br />
PSMAG<br />
April 11, 3:39 PM<br />
<br />
BY Michael White<br />
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(Translated by - 李昉)<br />
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A major advantage of using a funding lottery would be that, by reducing its reliance on peer-review rankings, the NIH would have more room to address the urgent problem of bias. A suitably designed lottery system could help eliminate the small but persistent gender gap, and the larger racial gap in the funding it awards, by giving NIH officers more leeway to include a representative set of proposals. And importantly, a lottery would be an honest acknowledgement of what most scientists already sense: that, despite its reputation for basing decisions on merit, peer review is a much more random process than we would like to admit.<br />
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用抽签决定基金的主要好处是减少对同行评审排名的依赖,国家卫生研究院(NIH)将有更多的空间来解决这个紧急问题。适当设计的抽签系统可以帮助消除微小但持续的性别差距,以及获取基金方面巨大的种族差异,并给予 NIH 工作人员在选择具有代表性的研究计划时更多的回旋余地。重要的是,对于抽签,大多数科学家已经坦然承认,尽管根据价值作出决策取得很多成绩,但同行评审是一个比我们理解的更具随机性的过程。<br />
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原文链接:https://psmag.com/why-the-national-institutes-of-health-should-replace-peer-review-with-a-lottery-41d09bcce5d8?gi=cf38b8f1f21d<br />
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edited by 傅渥成<br />
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== 混合型社会:设计自组织系统集群行为的挑战及前景 Hybrid Societies: Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems==<br />
Robotics and AI, <br />
April 11, 5:44 PM<br />
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BY Heiko Hamann, Yara Khaluf, Jean Botev, Mohammad Divband Soorati, Eliseo Ferrante, Oliver Kosak, Jean-Marc Montanier, Sanaz Mostaghim, Richard Redpath, Jonathan Timmis, Frank Veenstra, Mostafa Wahby, Aleš Zamuda<br />
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(Translated by -xiaomuqiu)<br />
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Hybrid societies are self-organizing, collective systems, which are composed of different components, for example, natural and artificial parts (bio-hybrid) or human beings interacting with and through technical systems (socio-technical). Many different disciplines investigate methods and systems closely related to the design of hybrid societies. A stronger collaboration between these disciplines could allow for re-use of methods and create significant synergies.We identify three main areas of challenges in the design of self-organizing hybrid societies. First, we identify the formalization challenge.There is an urgent need for a generic model that allows a description and comparison of collective hybrid societies. Second, we identify the system design challenge. Starting from the formal specification of the system, we need to develop an integrated design process. Third, we identify the challenge of interdisciplinarity. Current research on self-organizing hybrid societies stretches over many different fields and hence requires the re-use and synthesis of methods at intersections between disciplines. We then conclude by presenting our perspective for future approaches with high potential in this area.<br />
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混合型社会是一种由不同组件组成的自组织的集群系统,例如,天然和人工部分(生物混合系统)或人类与技术系统及通过技术系统相互作用(社会-技术系统)。许多不同学科所采用的研究方法和研究体系都与设计混合型社会有密切关联。这些学科间强有力的合作可以使方法得到重新使用,并创造显著的协同效应。我们明确了设计自组织混合型社会的三大领域的挑战。首先,我们明确了形式化的挑战。即迫切需要一个通用模型来描述和比较不同的混合型社会集群。其次,我们明确了系统设计的挑战。即我们需要从系统的形式化规范为起点,建立一个整合性的设计过程。第三,我们明确了跨学科的挑战。即自组织混合社会当前研究横跨许多不同的领域,因此我们需要将其方法在不同学科的交叉中进行综合再利用。最后,我们对这一高潜力领域未来的研究方法提出了观点。<br />
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原文链接:http://journal.frontiersin.org/article/10.3389/frobt.2016.00014/full<br />
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edited by 傅渥成<br />
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==通过稀疏识别从数据中发掘非线性动力系统的控制方程(Discovering governing equations from data by sparse identification of nonlinear dynamical systems) ==<br />
PNAS<br />
April 13, 3:45 PM<br />
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BY Steven L. Brunton, Joshua L. Proctor, and J. Nathan Kutz<br />
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(Translated by - [[User:Darthy|Darthy]])<br />
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Extracting governing equations from data is a central challenge in many diverse areas of science and engineering. Data are abundant whereas models often remain elusive, as in climate science, neuroscience, ecology, finance, and epidemiology, to name only a few examples. In this work, we combine sparsity-promoting techniques and machine learning with nonlinear dynamical systems to discover governing equations from noisy measurement data. The only assumption about the structure of the model is that there are only a few important terms that govern the dynamics, so that the equations are sparse in the space of possible functions; this assumption holds for many physical systems in an appropriate basis. In particular, we use sparse regression to determine the fewest terms in the dynamic governing equations required to accurately represent the data. This results in parsimonious models that balance accuracy with model complexity to avoid overfitting. We demonstrate the algorithm on a wide range of problems, from simple canonical systems, including linear and nonlinear oscillators and the chaotic Lorenz system, to the fluid vortex shedding behind an obstacle. The fluid example illustrates the ability of this method to discover the underlying dynamics of a system that took experts in the community nearly 30 years to resolve. We also show that this method generalizes to parameterized systems and systems that are time-varying or have external forcing.<br />
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通过稀疏识别从数据中发掘非线性动力系统的控制方程<br />
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如何从数据中提取控制方程是很多科学和工程领域面临的一个主要问题。在很多领域中,数据很多,模型却难以捉摸,例如气候科学、神经科学、生态学、金融和流行病学。在本文中,我们将稀疏技术和机器学习与非线性动力系统结合起来,从带噪声的观测数据中挖掘控制方程。对模型结构的唯一假设为:系统的动力学仅由很少的几个重要因素决定,因此方程在可能函数的空间中是稀疏的;这一假设在一定条件下对很多物理系统中都能成立。具体来说,我们使用稀疏回归来判定精确表示数据所需的动力学控制方程的最少因素。该方法所生成的精简模型能够在模型的精确性和复杂性之间进行平衡,避免过度拟合。我们用各种问题上验证了该算法的有效性,从简单的标准系统,包括线性和非线性振子系统,以及混沌洛伦兹系统,到障碍物后面形成的涡流。流体的例子证明了这个方法发现系统背后的动力学的能力,专家们曾花了近30年时间才解决这个问题。我们的研究还表明,该方法可以推广到参数化系统、时变系统或受到外力的系统中。<br />
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原文链接:http://www.pnas.org/content/113/15/3932.abstract<br />
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(Edited by 唐璐)<br />
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==捕食风险驱使合作育仔生物社会复杂化(Predation risk drives social complexity in cooperative breeders)==<br />
PNAS<br />
April 13, 9:14 PM<br />
<br />
BY Frank Groenewoud, Joachim Gerhard Frommena, Dario Josi, Hirokazu Tanaka, Arne Jungwirth, and Michael Taborsky<br />
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(Translated by -秦堉朗-ATC-ABM-Canton)<br />
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<br />
Significance<br />
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It is widely accepted that high predation risk may select for group living, but predation is not regarded as a primary driver of social complexity. This view neglects the important effect of predation on dispersal and offspring survival, which may require cooperation among group members. The significance of predation for the evolution of social complexity can be well illustrated by behavioral and morphological adaptations of highly social animals showing division of labor, such as eusocial insects and cooperatively breeding fishes. By examining the diversity of social organization in a cooperative cichlid in relation to ecological variation, we show that predation risk has the greatest explanatory power of social complexity. This stresses the significance of predation for social evolution.<br><br />
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Abstract<br />
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Predation risk is a major ecological factor selecting for group living. It is largely ignored, however, as an evolutionary driver of social complexity and cooperative breeding, which is attributed mainly to a combination of habitat saturation and enhanced relatedness levels. Social cichlids neither suffer from habitat saturation, nor are their groups composed primarily of relatives. This demands alternative ecological explanations for the evolution of advanced social organization. To address this question, we compared the ecology of eight populations of Neolamprologus pulcher, a cichlid fish arguably representing the pinnacle of social evolution in poikilothermic vertebrates. Results show that variation in social organization and behavior of these fish is primarily explained by predation risk and related ecological factors. Remarkably, ecology affects group structure more strongly than group size, with predation inversely affecting small and large group members. High predation and shelter limitation leads to groups containing few small but many large members, which is an effect enhanced at low population densities. Apparently, enhanced safety from predators by cooperative defense and shelter construction are the primary benefits of sociality. This finding suggests that predation risk can be fundamental for the transition toward complex social organization, which is generally undervalued.<br><br />
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研究意义:<br />
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人们普遍认为,高捕食风险会导致对群居特性的选择,但捕食没有被视为社会复杂化的主要推动力。这种观点忽视了捕食对疏散和后代存活的重要影响,这些可能需要群体成员之间的协作。展现出劳动分工的高度社会化的物种,例如真社会性昆虫和合作育仔鱼类,它们的行为和形态适应性就很好地揭示了捕食行为对社会复杂性进化的意义。通过研究一种合作性丽鱼的社会组织的多样性与生态变化的关系,我们发现捕食风险最能够解释社会复杂性。这个结果强调了捕食对社会进化的意义。<br />
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摘要:<br />
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捕食风险是群居特性选择的主要生态因素。然而,它对社会复杂性和合作育仔行为的进化驱动作用往往被忽视,这些主要被归因于生存环境饱和亲缘程度的提高。社会性丽鱼的生存环境并不饱和,它们的群体也不主要是由亲缘构成。这使得高级社会组织的进化需要另外一种生态学解释。为了解决这个问题,我们比较了八个美鳍亮丽鲷(Neolamprologus pulcher)群体的生态,这种丽鱼被认为是变温脊椎动物中社会进化的巅峰。结果表明,这些鱼的社会组织和行为的变化主要是因为捕食风险以及相关的生态因素。值得注意的是,生态对群体结构的影响甚于群体规模,捕食行为则影响鱼群的大小。捕食风险高和藏身处的匮乏使得大多数群体的成员数量都很多,只有少量群体的成员很少,这个效应又被低群体密度加强。显然,通过合作防御和建造藏身处降低被捕食的风险是社会性的主要好处。这个发现表明捕食风险对于向复杂社会组织的转化可能很重要,这一点在以前往往被低估。<br />
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原文链接:http://www.pnas.org/content/113/15/4104.abstract.html?etoc<br />
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(Edited by 唐璐)<br />
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== Facebook和YouTube用户的极化 (Users Polarization on Facebook and Youtube)==<br />
April 13, 11:18 PM<br />
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BY Alessandro Bessi, Fabiana Zollo, Michela Del Vicario, Michelangelo Puliga, Antonio Scala, Guido Caldarelli, Brian Uzzi, Walter Quattrociocchi<br />
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(Translated by - dan)<br />
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Algorithms for content promotion accounting for users preferences, might limit the exposure to unsolicited contents. In this work, we study how the same contents (videos) are consumed on different platforms -- i.e. Facebook and YouTube -- over a sample of 12M of users. Our findings show that the same content lead to the formation of echo chambers, irrespective of the online social network and thus of the algorithm for content promotion. Finally, we show that the users' commenting patterns are accurate early predictors for the formation of echo-chambers.<br />
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根据用户偏好的内容推介算法可能屏蔽偏好范围以外的内容。我们在1200万用户样本上研究了相同内容(视频)在不同平台上(例如,Facebook和YouTube)是如何被阅读的。我们发现,相同的内容就能导致形成回声室效应,与在线社交网络无关,因此也与内容推介算法无关。最后,我们发现,用户的评论模式能够提早准确地预测回声室的形成。<br />
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原文链接:http://arxiv.org/abs/1604.02705<br />
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(Edited by 唐璐)<br />
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==城市地区拥堵的全球分析( A global take on congestion in urban areas)==<br />
April 14, 3:38 PM<br />
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BY Marc Barthelemy<br />
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(Translated by -余思瑶)<br />
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We analyze the congestion data collected by a GPS device company (TomTom) for almost 300 urban areas in the world. Using simple scaling arguments and data fitting we show that congestion during peak hours in large cities grows essentially as the square root of the population density. This result, at odds with previous publications showing that gasoline consumption decreases with density, confirms that density is indeed an important determinant of congestion, but also that we need urgently a better theoretical understanding of this phenomena. This incomplete view at the urban level leads thus to the idea that thinking about density by itself could be very misleading in congestion studies, and that it is probably more useful to focus on the spatial redistribution of activities and residences.<br />
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我们分析了由一家GPS设备公司(TomTom)收集的全世界大约300个城市地区的拥堵数据。使用简单的缩放参数和数据拟合,我们发现,大城市中高峰时段的拥堵基本是随人口密度的平方根增长。这个结果,与之前出版物所显示的汽油消耗量随密度增加而减少的观点相悖,证实了人口密度确实是拥堵的一个重要的决定因素,我们也急需对这个现象有更好的理论认识。在城市层面上进行的分析的不完善,让我们意识到只考虑人口密度本身对于拥堵研究很有误导性,关注活动和居住的空间分布可能更有用。<br />
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原文链接:http://arxiv.org/abs/1604.03904<br />
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(Edited by 唐璐)<br />
<br />
== 手机通话的邓巴数(Calling Dunbar's Numbers) ==<br />
April 14, 5:40 PM<br />
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BY Pádraig MacCarron, Kimmo Kaski, Robin Dunbar<br />
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(Translated by - 卢罡)<br />
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The social brain hypothesis predicts that humans have an average of about 150 relationships at any given time. Within this 150, there are layers of friends of an ego, where the number of friends in a layer increases as the emotional closeness decreases. Here we analyse a mobile phone dataset, firstly, to ascertain whether layers of friends can be identified based on call frequency. We then apply different clustering algorithms to break the call frequency of egos into clusters and compare the number of alters in each cluster with the layer size predicted by the social brain hypothesis. In this dataset we find strong evidence for the existence of a layered structure. The clustering yields results that match well with previous studies for the innermost and outermost layers, but for layers in between we observe large variability.<br />
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社会脑假说预测,在任何时候,人类平均能够维系大约150个人际关系。在这150个人际关系中,存在分层次的朋友关系,层次的情感亲密度越低,该层次中朋友的数量越多。我们分析了一个移动电话通话数据集,首先确定是否能够根据通话频度分辨出朋友层次。然后,我们应用了不同的聚类算法,将个体的通话频次分成多个簇,并将每个簇的大小与社会脑假说所预测的层次大小进行比较。在这个数据集中,我们发现了层次结构存在的强有力证据。聚类产生的结果在最内和最外层次上与前人的研究结果高度吻合,但是我们观察到,中间那些层次的变化很大。<br />
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原文链接:http://arxiv.org/abs/1604.02400<br />
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(Edited by 唐璐)<br />
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==进化中的复杂系统的时间尺度探测 (Detection of timescales in evolving complex systems)==<br />
April 14, 7:43 PM<br />
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BY Richard K. Darst, Clara Granell, Alex Arenas, Sergio Gómez, Jari Saramäki, Santo Fortunato<br />
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(Translated by -张皓)<br />
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Most complex systems are intrinsically dynamic in nature. The evolution of a dynamic complex system is typically represented as a sequence of snapshots, where each snapshot describes the configuration of the system at a particular instant of time. Then, one may directly follow how the snapshots evolve in time, or aggregate the snapshots within some time intervals to form representative "slices" of the evolution of the system configuration. This is often done with constant intervals, whose duration is based on arguments on the nature of the system and of its dynamics. A more refined approach would be to consider the rate of activity in the system to perform a separation of timescales. However, an even better alternative would be to define dynamic intervals that match the evolution of the system's configuration. To this end, we propose a method that aims at detecting evolutionary changes in the configuration of a complex system, and generates intervals accordingly. We show that evolutionary timescales can be identified by looking for peaks in the similarity between the sets of events on consecutive time intervals of data. Tests on simple toy models reveal that the technique is able to detect evolutionary timescales of time-varying data both when the evolution is smooth as well as when it changes sharply. This is further corroborated by analyses of several real datasets. Our method is scalable to extremely large datasets and is computationally efficient. This allows a quick, parameter-free detection of multiple timescales in the evolution of a complex system.<br />
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世界上大多数的复杂系统本质上都是动态的。典型的方式是通过一系列快照来呈现动态复杂系统的进化,每一个快照都描述了在一个特定时间点的系统配置。如此,便可以直接跟踪快照是如何随时间而进化的,或者聚集一段时间间隔内的快照来形成具有代表性的系统配置进化的“切片”。通常采用恒定的间隔来实现,而间隔的长短基于系统及其动力学本质的论证。一个更优的方法是考虑系统的活动率来形成时间尺度上的划分。然而,进一步优化的选择是定义一个能够匹配系统配置进化的动态间隔。为此,我们提出了一个方法来探测复杂系统配置的变化,并相应生成时间间隔。 我们发现能够通过发掘在数据连续时间间隔上事件组相似性的峰值来确立进化的时间尺度。在一个简单的玩具模型的测试中揭示这项技术能够发现时变数据的进化时间尺度,无论进化是平滑的还是急剧的。通过分析真实的数据集进一步证实了这个观点。我们的方法能扩展到极大的数据集,并且计算效率高。这允许对复杂系统的进化进行快速的无参数的多个时间尺度的探测。<br />
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原文链接:http://arxiv.org/abs/1604.00758<br />
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Jake校对:<br />
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世界上大多数的复杂系统本质上都是动态的。我们通常是通过一系列的快照来呈现复杂系统的演化,每一个快照都描述了系统在一个特定时间点的状态信息。如此,我们便可以直接跟踪这些快照是如何随时间而演化的,或者通过将一段时间间隔内的快照聚集在一起来形成具有代表性的系统状态演化的“切片”。我们通常采用恒定的间隔来实现上述操作,而间隔的长短取决于我们对系统及其动力学本质的判断。根据系统的活动快慢来确定时间尺度的划分也许是个更好的方案。而更好的替代方案是定义一个能够匹配系统状态演化的动态间隔。为此,我们提出了一种探测复杂系统状态变化的方法,并由此生成时间间隔。 我们展示了,可以根据数据中连续时间发生的事件所产生的峰值相似性来确定演化的时间尺度。在一个简单的玩具模型中,我们进行了测试,揭示出这项技术能够发现时变数据的演化化时间尺度,无论演化是平滑的还是急剧的。进一步,通过分析不同的真实数据集,我们进一步证实了这个观点。我们的方法能扩展到极大的数据集,并且计算效率很高。这使得我们可以对复杂系统的演化化进行快速的无参数的多尺度探测。<br />
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==A Possible Link Between Pyriproxyfen and Microcephaly ==<br />
April 14, 8:36 PM<br />
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BY Dan Evans, Fred Nijhout, Raphael Parens, Alfredo J. Morales, Yaneer Bar-Yam<br />
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(Translated by -)<br />
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The Zika virus is the primary suspect in the large increase in microcephaly cases in 2015-6 in Brazil, however its role is unconfirmed despite individual cases of viral infections found in neural tissue. Here we consider the alternative that the insecticide pyriproxyfen, used in Brazilian drinking water for mosquito control, may actually be the cause. Pyriproxifen is an analog of juvenile hormone, which corresponds in mammals to regulatory molecules including retinoic acid, a vitamin A metabolite, with which it has cross-reactivity and whose application during development causes microcephaly. Methoprene, another juvenile hormone analog approved as an insecticide has metabolites that bind to the retinoid X receptor, and causes developmental disorders in mammals. Isotretinoin is another example of a retinoid causing microcephaly in human babies via activation of the retinoid X receptor. Moreover, tests of pyriproxyfen by the manufacturer, Sumitomo, widely quoted as giving no evidence for developmental toxicity, actually found some evidence for such an effect, including low brain mass and arhinencephaly--incomplete formation of the anterior cerebral hemispheres--in rat pups. Finally, the pyriproxyfen use in Brazil is unprecedented--it has never before been applied to a water supply on such a scale. Claims that it is not being used in Recife, the epicenter of microcephaly cases, do not distinguish the metropolitan area of Recife, where it is widely used, and the municipality, where it is not. Given this combination of information we strongly recommend that the use of pyriproxyfen in Brazil be suspended pending further investigation.<br />
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原文链接:http://arxiv.org/abs/1604.03834<br />
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==时间片:感知的过程是什么? Time Slices: What Is the Duration of a Percept?==<br />
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题目中的duration应该翻译为时长,所以建议:<br />
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==时间片:感知的持续时间是什么? Time Slices: What Is the Duration of a Percept?==<br />
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PLOS<br />
April 14, 11:49 PM<br />
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BY Michael H. Herzog, Thomas Kammer, Frank Scharnowski<br />
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(Translated by -dan)<br />
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We experience the world as a seamless stream of percepts. However, intriguing illusions and recent experiments suggest that the world is not continuously translated into conscious perception. Instead, perception seems to operate in a discrete manner, just like movies appear continuous although they consist of discrete images. To explain how the temporal resolution of human vision can be fast compared to sluggish conscious perception, we propose a novel conceptual framework in which features of objects, such as their color, are quasi-continuously and unconsciously analyzed with high temporal resolution. Like other features, temporal features, such as duration, are coded as quantitative labels. When unconscious processing is “completed,” all features are simultaneously rendered conscious at discrete moments in time, sometimes even hundreds of milliseconds after stimuli were presented.<br />
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Jake:<br />
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我们感知的世界是无缝的知觉流。然而,有趣的幻觉和近期的一些实验都暗示这个世界是非连续被意识感知的。反而,感知更像是离散的,就像电影看起来是连续的,但实际上是离散画面组成的一样。为了解释相比于缓慢的意识感知来说,人类视觉处理的时间分辨率有多快,我们提出了一个新的概念框架,其中物体的特征,比如颜色,是由潜意识用高时间分辨率分析的,是准连续的。时间特征,比如持续时间,也如同其他特征一样被编码为量化的标签。当潜意识处理完成以后,所有的特征才同步地被意识以离散的方式感知,有时甚至发生在刺激之后的几百个毫秒。<br />
<br />
我们感知的世界是无缝的知觉流。然而,迷人的错觉和最近的实验都暗示这个世界是非连续转化为意识感知的。反而,感知更像是离散的,就像电影看起来是连续的,但实际上电影是离散画面组成的。为了解释人类视觉处理的时间分辨率相比缓慢的意识感知有多快,我们提出了一个新的概念框架,其中物体的特性,比如颜色,是由潜意识用高时间分辨率分析的,是准连续的。如同其他特性一样,时间特性,比如持续时间,也编码为数字标签。当潜意识处理完成以后,所有的特性才同步地被意识感知,并且在时间上是离散的,有时滞后刺激源的出现达几百个毫秒。<br />
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原文链接: http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002433<br />
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==通过电脑游戏探索量子速度极限 Exploring the quantum speed limit with computer games ==<br />
Nature 532, 210–213 (14 April 2016) <br />
April 15, 6:57 PM<br />
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BY Jens Jakob W. H. Sørensen, Mads Kock Pedersen, Michael Munch, Pinja Haikka, Jesper Halkjær Jensen, Tilo Planke, Morten Ginnerup Andreasen, Miroslav Gajdacz, Klaus Mølmer, Andreas Lieberoth & Jacob F. Sherson<br />
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(Translated by -秦德盛)<br />
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Humans routinely solve problems of immense computational complexity by intuitively forming simple, low-dimensional heuristic strategies. Citizen science (or crowd sourcing) is a way of exploiting this ability by presenting scientific research problems to non-experts. ‘Gamification’—the application of game elements in a non-game context—is an effective tool with which to enable citizen scientists to provide solutions to research problems. The citizen science games Foldit, EteRNA and EyeWire have been used successfully to study protein and RNA folding and neuron mapping, but so far gamification has not been applied to problems in quantum physics. Here we report on Quantum Moves, an online platform gamifying optimization problems in quantum physics. We show that human players are able to find solutions to difficult problems associated with the task of quantum computing. Players succeed where purely numerical optimization fails, and analyses of their solutions provide insights into the problem of optimization of a more profound and general nature. Using player strategies, we have thus developed a few-parameter heuristic optimization method that efficiently outperforms the most prominent established numerical methods. The numerical complexity associated with time-optimal solutions increases for shorter process durations. To understand this better, we produced a low-dimensional rendering of the optimization landscape. This rendering reveals why traditional optimization methods fail near the quantum speed limit (that is, the shortest process duration with perfect fidelity)7, 8, 9. Combined analyses of optimization landscapes and heuristic solution strategies may benefit wider classes of optimization problems in quantum physics and beyond.<br />
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Jake校对:<br />
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人们往往通过直观的方式形成低维度的简单启发式策略,从而解决具有巨大计算复杂性的问题。公民科学(或称众包)是一种通过向非专业人群提出科学研究问题来开发该能力的途径。“游戏化”——在非游戏背景下运用游戏元素——是一种非常有效的工具,它可以向公民科学家提供研究问题的解决方案。公民科学游戏Foldit、EteRNA和EyeWire已经成功地将这种方法应用于蛋白质和RNA的折叠以及神经元映射的研究当中。但是到目前为止,游戏化尚未应用于量子物理的问题研究中。在这里,我们提出了一个量子移动游戏(Quantum Moves),它是一个可以将量子物理领域中的优化问题进行游戏化的在线平台。我们发现,人类玩家可以解决量子计算领域中具有挑战意义的难题。玩家可以在纯数值优化方法失败之处取得成功,并且他们的策略可以为研究人员在优化问题上提供一种更深刻而普适的视角。凭借玩家的策略,我们已经开发出一种多参数的启发式优化方法,它明显优于现有的最优秀的数值算法。对于较短的过程来说,它的数值复杂性(与时间最优解相关)会不断增加。为了更好地理解这一点,我们生成了一个最优景观的低维渲染图,以揭示为什么传统优化方法在接近量子速度极限(即完美保真度的最短持续时间)的时候会失败。将景观优化和启发式求解策略相结合可能有利于量子物理乃至更多领域中广泛存在的优化问题的求解。<br />
注:citizen science,直译为公民科学,也作公众科学、群智科学。<br />
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人们通常采用直观地形成启发式策略的方法来解决巨大的计算复杂性问题,这种策略是简单而低维的。公民科学(或是群体采购)是开发该能力的一种途径,它是向非专业人群提出科学研究问题。“游戏化”——在非游戏背景下运用游戏元素——是一个非常有效的工具,它可以使公民科学家提供研究问题的解决方案。公民科学游戏Foldit、EteRNA和EyeWire成功的应用于蛋白质和RNA折叠研究以及神经元映射研究当中,但是到目前为止,游戏化尚未应用于量子物理的问题研究中。在这里,我们报告一个量子移动游戏(Quantum Moves),它是一个可以将量子物理领域中的优化问题游戏化的在线平台。我们发现,人类玩家可以寻找到与量子计算挑战相关的难题的解决方案。在纯粹的数值优化失败之处,玩家却可以取得成功,分析他们的策略可以为优化问题提供一种更深刻而一般性的视角。凭借使用玩家策略,我们已经开发出一种多参数启发式优化方法,这种方法明显优于现有的优秀数值方法。较短的持续时间内,与时间优化解法相关的数值复杂性在增加。为了更好地理解这一点,我们提供了一个景观优化的低维效果图。这一效果图揭示了传统优化方法在接近量子速度极限(即完美保真度的最短持续时间)时为何失败了。景观优化和启发式解法策略的结合可能有利于量子物理以及更多领域内广泛种类的优化问题。<br />
注:citizen science,直译为公民科学,也作公众科学、群智科学。<br />
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原文链接:http://www.nature.com/nature/journal/v532/n7598/full/nature17620.html<br />
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==从大数据到重要信息(From Big Data To Important Information) ==<br />
April 15, 10:34 PM<br />
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BY Yaneer Bar-Yam<br />
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(Translated by - 猪哥)<br />
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Advances in science are being sought in newly available opportunities to collect massive quantities of data about complex systems. While key advances are being made in detailed mapping of systems, how to relate this data to solving many of the challenges facing humanity is unclear. The questions we often wish to address require identifying the impact of interventions on the system and that impact is not apparent in the detailed data that is available. Here we review key concepts and motivate a general framework for building larger scale views of complex systems and for characterizing the importance of information in physical, biological and social systems. We provide examples of its application to evolutionary biology with relevance to ecology, biodiversity, pandemics, and human lifespan, and in the context of social systems with relevance to ethnic violence, global food prices, and stock market panic. Framing scientific inquiry as an effort to determine what is important and unimportant is a means for advancing our understanding and addressing many practical concerns, such as economic development or treating disease.<br />
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Jake审校:<br />
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不断发展着的科学正在寻找新的契机去收集大量关于复杂系统的数据。人们虽然在系统的细节结构上取得了重要进展,但还不清楚如何运用这些数据去解决人类所面临的挑战。我们希望解决的问题通常需要确定人为干预如何对系统产生影响,而这些影响在现有的详细数据中并不明显。在这里,我们对一些重要概念进行回顾,并试图建立一个一般的框架来构建复杂系统的大型视图,并刻画出信息在物理、生物和社会系统中的重要性。我们提供了将其应用于与生态、生物多样性、流行病学以及人类寿命相关的进化生物学之中;以及与种族暴力、全球粮食价格和股市恐慌相关的社会系统之中的案例。通过将科学探究转化为一种确定什么重要什么不重要的问题,我们对于许多实际问题如经济发展或疾病治疗会有更深的理解。<br />
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不断发展着的科学正在寻找新的契机去收集大量关于复杂系统的数据。人们虽然在系统的详细结构上取得了重要进展,但还不清楚如何运用这些数据去解决人类所面临的挑战。我们希望解决的问题需要确定人为干预对系统的影响,而这些影响在现有的详细数据中并不明显。在这里,我们审视重要概念,促使建立一个一般的框架来构建复杂系统的大型视图,并表征物理、生物和社会系统中信息的重要性。我们提供了其应用于与生态学、生物多样性、流行病和人类寿命相关的进化生物学,以及与种族暴力、全球粮食价格和股市恐慌相关的社会系统背景下的例子。努力让科学探究成为确定信息重要还是不重要的依据,有利于促进我们对许多实际关心的问题的理解和解决,比如经济的发展或疾病的治疗。<br />
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原文链接:http://arxiv.org/abs/1604.00976<br />
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== 自适应社会网络中从个体到集体行为的连接 Linking Individual and Collective Behavior in Adaptive Social Networks==<br />
<br />
Phys. Rev. Lett. 116, 128702<br />
April 15, 11:28 PM<br />
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BY Flávio L. Pinheiro, Francisco C. Santos, and Jorge M. Pacheco<br />
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(Translated by -高德华)<br />
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Adaptive social structures are known to promote the evolution of cooperation. However, up to now the characterization of the collective, population-wide dynamics resulting from the self-organization of individual strategies on a coevolving, adaptive network has remained unfeasible. Here we establish a (reversible) link between individual (micro)behavior and collective (macro)behavior for coevolutionary processes. We demonstrate that an adaptive network transforms a two-person social dilemma locally faced by individuals into a collective dynamics that resembles that associated with an N-person coordination game, whose characterization depends sensitively on the relative time scales between the entangled behavioral and network evolutions. In particular, we show that the faster the relative rate of adaptation of the network, the smaller the critical fraction of cooperators required for cooperation to prevail, thus establishing a direct link between network adaptation and the evolution of cooperation. The framework developed here is general and may be readily applied to other dynamical processes occurring on adaptive networks, notably, the spreading of contagious diseases or the diffusion of innovations.<br />
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原文链接:http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.128702<br />
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Jake:<br />
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人们已经知道,适应性社会结构能够促进合作的演化。然而直至目前,要对共生演化的自适应网络上由个体策略自组织所产生的全种群范围的集体动力学进行刻画仍然是比较困难的。在本文中,我们在个体(微观)行为和集体(宏观)行为之间建立起一种(可逆的)连接,并将其视为是一个共生演化的过程。我们的研究证明:自适应网络将个体在局部面临的双人社会困境转变成了类似于N人协调博弈的集体动力学,其表征敏感地依赖于所涉及的行为和网络演化的相对时间尺度。特别地,我们的研究表明:网络适应的相对速率越快,合作的扩散所需的合作者的临界比例就越小,由此我们在网络适应性和合作演化两者之间建立了一种直接的联系。我们所提出的这个框架具有一般性,可以较容易地应用于适应性网络上的其他动力学过程,如疾病的传播或者创新的扩散。<br />
<br />
人们已经知道,适应性社会结构能够促进合作的演化。然而直至目前,要对共生演化的自适应网络上由个体策略自组织所产生的全种群范围的集体动力学进行刻画仍然是比较困难的。本文中,我们在个体(微观)行为和集体(宏观)行为之间建立起连接,并将其视为是一个共生演化的过程。我们的研究证明:自适应网络将个体在局部面临的双人社会困境转变成了类似于N人协调博弈相关联的集体动力学,其表征敏感依赖于所涉及为和网络演化之间的相对时间尺度。进而,我们的研究表明:网络适应的相对速率越快,合作所需合作者的临界比例就越小,由此在网络适应性和合作演化两者之间建立了直接的联系。我们所提出的这个框架具有一般性,可以较容易地应用于适应性网络上所发生的其他动力学过程,如传染性疾病的传播或者创新的扩散。<br />
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==多层网络上的物理 The physics of multilayer networks==<br />
April 16, 3:33 PM<br />
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BY Manlio De Domenico, Clara Granell, Mason A. Porter, Alex Arenas<br />
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(Translated by 蔡嘉文)<br />
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The study of networks plays a crucial role in investigating the structure, dynamics, and function of a wide variety of complex systems in myriad disciplines. Despite the success of traditional network analysis, standard networks provide a limited representation of these systems, which often includes different types of relationships (i.e., "multiplexity") among their constituent components and/or multiple interacting subsystems. Such structural complexity has a significant effect on both dynamics and function. Throwing away or aggregating available structural information can generate misleading results and provide a major obstacle towards attempts to understand the system under analysis. The recent "multilayer' approach for modeling networked systems explicitly allows the incorporation of multiplexity and other features of realistic networked systems. On one hand, it allows one to couple different structural relationships by encoding them in a convenient mathematical object. On the other hand, it also allows one to couple different dynamical processes on top of such interconnected structures. The resulting framework plays a crucial role in helping to achieve a thorough, accurate understanding of complex systems. The study of multilayer networks has also revealed new physical phenomena that remained hidden when using the traditional network representation of graphs. Here we survey progress towards a deeper understanding of dynamical processes on multilayer networks, and we highlight some of the physical phenomena that emerge from multilayer structure and dynamics.<br />
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网络研究是调查无数学科中多种类的复杂系统的结构,动力学,功能的关键。尽管传统网络分析取得了成功,但是由于复杂系统中的组成结构和大量互相作用的子系统(多元复杂性 multiplexity),普通网络难以对其进行完善的表示。这种结构上的复杂性对动力学和功能都有着重要的作用。如果简单地丢掉或者聚合可用的结构信息可能产生错误的结果并对系统的内在机制的理解造成阻碍。最近的“多层网络”模型能够使我们能够清晰地建模出这种多元复杂性以及其他真实网络系统的特征。一方面,这种方法使得我们可以将不同的结构关系编码到一个易用的数学对象。另一方面,我们可以在这种相互连接的结构上尝试不同种类的动力学过程。这个框架是对复杂系统建立完善而准确的理解的关键。对多层网络的研究也揭示出了一些在传统网络结构的图表示下被隐藏的物理过程。在这里我们试图对多层网络上的动力学过程建立更深刻的理解,并且着重突出了一些随多层网络结构及其动力学而涌现出来的物理现象。<br />
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edited by 傅渥成<br />
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原文链接:http://arxiv.org/abs/1604.02021#<br />
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==专题:含时网络理论及应用 (Modern temporal network theory: a colloquium) ==<br />
Eur. Phys. J. B (2015) 88: 234 <br />
April 16, 7:24 PM<br />
<br />
BY Petter Holme<br />
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(Translated by -)<br />
<br />
The power of any kind of network approach lies in the ability to simplify a complex system so that one can better understand its function as a whole. Sometimes it is beneficial, however, to include more information than in a simple graph of only nodes and links. Adding information about times of interactions can make predictions and mechanistic understanding more accurate. The drawback, however, is that there are not so many methods available, partly because temporal networks is a relatively young field, partly because it is more difficult to develop such methods compared to for static networks. In this colloquium, we review the methods to analyze and model temporal networks and processes taking place on them, focusing mainly on the last three years. This includes the spreading of infectious disease, opinions, rumors, in social networks; information packets in computer networks; various types of signaling in biology, and more. We also discuss future directions.<br />
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原文链接:http://link.springer.com/article/10.1140%2Fepjb%2Fe2015-60657-4<br />
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任何网络方法的力量在于简化复杂系统的能力,通过这种简化,我们可以更好地理解其作为一个整体的功能。然而,有时更多的信息是比只有点和边的简单图更有益的。添加关于相互作用时间信息可以使预测和机制理解更准确。然而,对应的缺点是没有太多可用的方法,部分是因为含时网络是相对年轻的领域,部分是因为相比于静态网络,发展这样的方法更加困难。在本次专题上,我们回顾了在过去三年间的分析和建模含时网络和及与之相关的各种过程的方法 。这些研究包括传染病、观点、谣言在社交网络中的传播;计算机网络中的信息包;生物学中各种类型的信号。我们还讨论了该领域未来的发展方向。<br />
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edited by 傅渥成<br />
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==标度非线性?(Is this scaling nonlinear? )==<br />
arXiv:1604.02872 physics.soc-ph <br />
April 16, 9:20 PM<br />
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BY J. C. Leitao, J.M. Miotto, M. Gerlach, E. G. Altmann<br />
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(Translated by - 刘清晴)<br />
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One of the most celebrated findings in complex systems in the last decade is that different indexes y (e.g., patents) scale nonlinearly with the population-x of the cities in which they appear, i.e., y∼x^β, β≠1. More recently, the generality of this finding has been questioned in studies using new databases and different definitions of city boundaries. In this paper we investigate the existence of nonlinear scaling using a probabilistic framework in which fluctuations are accounted explicitly. In particular, we show that this allows not only to (a) estimate β and confidence intervals, but also to (b) quantify the evidence in favor of β≠1 and (c) test the hypothesis that the observations are compatible with the nonlinear scaling. We employ this framework to compare 5 different models to 15 different datasets and we find that the answers to points (a)-(c) crucially depend on the fluctuations contained in the data, on how they are modeled, and on the fact that the city sizes are heavy-tailed distributed.<br />
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近10年来复杂系统研究领域中最著名的发现之一是:不同的指标y(如专利数)随着城市人口x非线性变化,呈现出某些规律,如 y∼x^β, β≠1。最近,在一些使用了新的数据库并用不同的方法定义城市边界的研究中,这个发现的普适性受到了质疑。在本文中,我们用一种概率论的框架研究了非线性标度的存在性,在研究中,我们可以将涨落明确地描述出来。特别地,我们发现这种方法不仅允许(a)估计β和置信区间,还允许(b)量化支持β≠1的证据,并且(c)检验观察数据符合非线性标度的假设。我们使用这种研究思路来比较了为15个不同的数据库建模的5个不同的模型,我们发现,数据的涨落、建模方法和城市规模为重尾分布的事实对(a)~(c)的结果是至关重要的。<br />
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原文链接:http://arxiv.org/abs/1604.02872<br />
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edited by 傅渥成<br />
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==复杂网络的控制需要结构和动态 Control of complex networks requires both structure and dynamics ==<br />
<br />
Scientific Reports 6, Article number: 24456 (2016)<br />
April 19, 11:50 PM<br />
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BY Alexander J. Gates & Luis M. Rocha<br />
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(Translated by -女周瑜)<br />
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The study of network structure has uncovered signatures of the organization of complex systems. However, there is also a need to understand how to control them; for example, identifying strategies to revert a diseased cell to a healthy state, or a mature cell to a pluripotent state. Two recent methodologies suggest that the controllability of complex systems can be predicted solely from the graph of interactions between variables, without considering their dynamics: structural controllability and minimum dominating sets. We demonstrate that such structure-only methods fail to characterize controllability when dynamics are introduced. We study Boolean network ensembles of network motifs as well as three models of biochemical regulation: the segment polarity network in Drosophila melanogaster, the cell cycle of budding yeast Saccharomyces cerevisiae, and the floral organ arrangement in Arabidopsis thaliana. We demonstrate that structure-only methods both undershoot and overshoot the number and which sets of critical variables best control the dynamics of these models, highlighting the importance of the actual system dynamics in determining control. Our analysis further shows that the logic of automata transition functions, namely how canalizing they are, plays an important role in the extent to which structure predicts dynamics.<br />
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对网络结构的研究揭示了复杂系统组织的鲜明特征。然而,我们还需要去理解如何控制复杂系统,例如确认将病变细胞恢复到健康状态或是将成熟细胞变成多能状态的策略。两个最近的研究方法表明,复杂系统的可控性仅仅通过变量间相互作用的拓扑、而不考虑它们的动力学就能被预测,即结构可控性和最小支配集。我们证明了这种只关注结构的方法在动力学被引入时很难描绘出系统的可控性特征。我们研究了网络基序的布尔网络集合以及生物化学调控的三种模型,即黑腹果蝇的体节极性网络、酿酒酵母的细胞周期和拟南芥中花器官的排列。我们论证了只关注结构的方法要么低估要么高估了关键变量的数量和哪组关键变量最好地控制了这些模型的动力学,从而突出了实际动力学在系统控制中的重要性。我们的分析进一步显示了自动机转换功能的逻辑(即它们是如何被引导的)在结构预测动态的程度中发挥着重要的作用。<br />
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原文链接:http://www.nature.com/articles/srep24456<br />
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edited by 傅渥成<br />
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== 有重尾的符号分布频率的相似点(Similarity of Symbol Frequency Distributions with Heavy Tails)==<br />
Phys. Rev. X 6, 021009<br />
April 21, 9:45 PM<br />
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BY Martin Gerlach, Francesc Font-Clos, and Eduardo G. Altmann<br />
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(Translated by -王与剑)<br />
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A mathematical technique for comparing large symbol sets suggests that less frequently used words are mainly responsible for the evolution of the English language over the past two centuries.<br />
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原文链接:http://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.021009<br />
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用一种数学手段对比大量的符号集合,结果表明使用频率较少的单词对于过去两个世纪的英语语言的演变起了主要作用。<br />
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==Understanding how biodiversity unfolds through time under neutral theory==<br />
Philosophical transactions of the royal society B<br />
April 22, 3:38 PM<br />
<br />
BY Olivier Missa, Calvin Dytham, Hélène Morlon<br />
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(Translated by -)<br />
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Theoretical predictions for biodiversity patterns are typically derived under the assumption that ecological systems have reached a dynamic equilibrium. Yet, there is increasing evidence that various aspects of ecological systems, including (but not limited to) species richness, are not at equilibrium. Here, we use simulations to analyse how biodiversity patterns unfold through time. In particular, we focus on the relative time required for various biodiversity patterns (macroecological or phylogenetic) to reach equilibrium. We simulate spatially explicit metacommunities according to the Neutral Theory of Biodiversity (NTB) under three modes of speciation, which differ in how evenly a parent species is split between its two daughter species. We find that species richness stabilizes first, followed by species area relationships (SAR) and finally species abundance distributions (SAD). The difference in timing of equilibrium between these different macroecological patterns is the largest when the split of individuals between sibling species at speciation is the most uneven. Phylogenetic patterns of biodiversity take even longer to stabilize (tens to hundreds of times longer than species richness) so that equilibrium predictions from neutral theory for these patterns are unlikely to be relevant. Our results suggest that it may be unwise to assume that biodiversity patterns are at equilibrium and provide a first step in studying how these patterns unfold through time.<br />
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原文链接:http://rstb.royalsocietypublishing.org/content/371/1691/20150226<br />
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==Parasites Are Us ==<br />
nautil.us<br />
April 22, 5:41 PM<br />
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BY ROBERT V. LEVINE<br />
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(Translated by -)<br />
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But if the mitochondria are me, doesn’t this mean I have two sets of genes? Aren’t I a mosaic of both my own cellular DNA and that of my mitochondria? The fact is that all of the “others”—whether they are parasitic or mutualistic, cheaters or straight-shooters, long-term residents or one-night stands—have a significant characteristic in common: They each carry their own DNA. And this means that, for however long they are inside their host’s body, two genetically distinct organisms are living under the same skin and, to one extent or another, are biologically intertwined. Deep down, at the core of our tissue, we are a gigantic, symbiotic array, a ragtag assortment of organisms. All of these are to some degree us.<br />
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原文链接:http://nautil.us/issue/35/boundaries/parasites-are-us<br />
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== Waste not, want not, emit less==<br />
Science 22 Apr 2016:Vol. 352, Issue 6284, pp. 408-409<br />
April 22, 5:54 PM<br />
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BY Jessica Aschemann-Witzel<br />
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(Translated by -)<br />
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Ensuring a sufficient supply of quality food for a growing human population is a major challenge, aggravated by climate change and already-strained natural resources. Food security requires production of some food surpluses to safeguard against unpredictable fluctuations (1). However, when food is wasted, not only has carbon been emitted to no avail, but disposal and decomposition in landfills create additional environmental impacts. Decreasing the current high scale of food waste is thus crucial for achieving resource-efficient, sustainable food systems (2). But, although avoiding food waste seems an obvious step toward sustainability, especially given that most people perceive wasting food as grossly unethical (3), food waste is a challenge that is not easily solved.<br />
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原文链接:http://science.sciencemag.org/content/352/6284/408<br />
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== Microbiome: Eating for trillions ==<br />
Nature 532, 316–317 (21 April 2016<br />
April 22, 7:41 PM<br />
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BY Derrick M. Chu & Kjersti M. Aagaard<br />
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(Translated by -) <br />
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Three studies investigate the bacteria in the guts of malnourished children and find that, when this microbiota is transferred into mice, supplements of certain microbes or sugars from human breast milk can restore normal growth.<br />
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原文链接:http://www.nature.com/nature/journal/v532/n7599/full/nature17887.html<br />
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== An Experimental Study of Team Size and Performance on a Complex Task ==<br />
PLoS ONE 11(4)<br />
April 23, 7:34 PM<br />
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By Mao A, Mason W, Suri S, Watts DJ <br />
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(Translated by -)<br />
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The relationship between team size and productivity is a question of broad relevance across economics, psychology, and management science. For complex tasks, however, where both the potential benefits and costs of coordinated work increase with the number of workers, neither theoretical arguments nor empirical evidence consistently favor larger vs. smaller teams. Experimental findings, meanwhile, have relied on small groups and highly stylized tasks, hence are hard to generalize to realistic settings. Here we narrow the gap between real-world task complexity and experimental control, reporting results from an online experiment in which 47 teams of size ranging from n = 1 to 32 collaborated on a realistic crisis mapping task. We find that individuals in teams exerted lower overall effort than independent workers, in part by allocating their effort to less demanding (and less productive) sub-tasks; however, we also find that individuals in teams collaborated more with increasing team size. Directly comparing these competing effects, we find that the largest teams outperformed an equivalent number of independent workers, suggesting that gains to collaboration dominated losses to effort. Importantly, these teams also performed comparably to a field deployment of crisis mappers, suggesting that experiments of the type described here can help solve practical problems as well as advancing the science of collective intelligence.<br />
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原文链接:http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153048<br />
<br />
== Why Physics Is Not a Discipline ==<br />
From nautil.us <br />
April 24, 1:38 AM<br />
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By PHILIP BALL<br />
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(Translated by -)<br />
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''Saying that physics knows no boundaries is not the same as saying that physicists can solve everything. They too have been brought up inside a discipline, and are as prone as any of us to blunder when they step outside. The issue is not who “owns” particular problems in science, but about developing useful tools for thinking about how things work—which is what Aristotle tried to do over two millennia ago. Physics is not what happens in the Department of Physics. The world really doesn’t care about labels, and if we want to understand it then neither should we.''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://nautil.us/issue/35/boundaries/why-physics-is-not-a-discipline<br />
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== Why we need democracy 2.0 and capitalism 2.0 to survive ==<br />
From futurict.blogspot.ch<br />
April 26, 8:34 PM<br />
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By Dirk Helbing (ETH Zurich/TU Delft)<br />
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(Translated by -) <br />
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''The world is running into great trouble. The anthropocene challenges (including climate change, impending resource shortages, demographic change, conflict, financial and economic crises) call for entirely new answers. As a result, we are now seeing the emergence of data-driven societies around the globe. Feudalism 2.0, fascism 2.0, communism 2.0, socialism 2.0, democracy 2.0 and capitalism 2.0 can now be built. What framework should we choose? What would be the implications?''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://futurict.blogspot.ch/2016/04/why-we-need-democracy-20-and-capitalism.html<br />
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== Estimating biologically relevant parameters under uncertainty for experimental within-host murine West Nile virus infection ==<br />
From rsif.royalsocietypublishing.org<br />
April 27, 9:17 PM<br />
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By Soumya Banerjee, Jeremie Guedj, Ruy M. Ribeiro, Melanie Moses, Alan S. Perelson<br />
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(Translated by -)<br />
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''West Nile virus (WNV) causes viral encephalitis in humans, and is related to viruses such as Dengue and Zika that are also of significant public health concern. We have developed a computational method to determine characteristics of WNV infection even in the face of limited experimental data. This could be applicable to other emerging diseases like Zika virus for which there is little data. It may be particularly useful to estimate the potential rate of within-host viral reproduction early in an outbreak in order to assess the epidemic potential of emerging pathogens.''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://rsif.royalsocietypublishing.org/content/13/117/20160130<br />
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== A model to identify urban traffic congestion hotspots in complex networks ==<br />
From arxiv.org<br />
April 28, 3:00 PM<br />
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By Albert Solé-Ribalta, Sergio Gómez, Alex Arenas<br />
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(Translated by -)<br />
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''Traffic congestion is one of the most notable problems arising in worldwide urban areas, importantly compromising human mobility and air quality. Current technologies to sense real-time data about cities, and its open distribution for analysis, allow the advent of new approaches for improvement and control. Here, we propose an idealized model, the Microscopic Congestion Model, based on the critical phenomena arising in complex networks, that allows to analytically predict congestion hotspots in urban environments. Results on real cities' road networks, considering, in some experiments, real-traffic data, show that the proposed model is capable of identifying susceptible junctions that might become hotspots if mobility demand increases.''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://arxiv.org/abs/1604.07728<br />
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== Spatial Patterns in Urban Systems ==<br />
From arxiv.org<br />
April 28, 5:09 PM<br />
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By Hoai Nguyen Huynh, Evgeny Makarov, Erika Fille Legara, Christopher Monterola, Lock Yue Chew<br />
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(Translated by -)<br />
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''Understanding the morphology of an urban system is an important step toward unveiling the dynamical processes of its growth and development. At the foundation of every urban system, transportation system is undeniably a crucial component in powering the life of the entire urban system. In this work, we study the spatial pattern of 73 cities across the globe by analysing the distribution of public transport points within the cities. The analysis reveals that different spatial distributions of points could be classified into four groups with distinct features, indicating whether the points are clustered, dispersed or regularly distributed. From visual inspection, we observe that the cities with regularly distributed patterns do not have apparent centre in contrast to the other two types in which star-node structure, i.e. monocentric, can be clearly observed. Furthermore, the results provide evidence for the existence of two different types of urban system: well-planned and organically grown. We also study the spatial distribution of another important urban entity, the amenities, and find that it possesses universal properties regardless of the city's spatial pattern type. This result has one important implication that at small scale of locality, the urban dynamics cannot be controlled even though the regulation can be done at large scale of the entire urban system. The relation between the distribution of amenities within the city and its spatial pattern is also discussed.''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://arxiv.org/abs/1604.07119<br />
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== Merging evolutionary history into species interaction networks ==<br />
From onlinelibrary.wiley.com<br />
April 28, 7:20 PM<br />
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By Guadalupe Peralta<br />
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(Translated by -)<br />
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'' The occurrence of complex networks of interactions among species not only relies on species co-occurrence, but also on inherited traits and evolutionary events imprinted in species phylogenies. The phylogenetic signal found in ecological networks suggests that evolution plays an important role in determining community assembly and hence could inform about the underpinning mechanisms.''<br />
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(请在此输入译文)<br />
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'''原文链接:'''http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12669/full<br />
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== Efficient network structures with separable heterogeneous connection costs ==<br />
From www.sciencedirect.com<br />
April 28, 9:18 PM<br />
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By Babak Heydari, Mohsen Mosleh, Kia Dalili<br />
(Translated by -)<br />
<br />
''We provide the analytical solution for the efficient network with heterogeneous, separable connection costs.<br />
The efficient network has a diameter no bigger than two and exhibits a core–periphery structure.<br />
We calculate the lower bound for clustering coefficient of the efficient network.''<br />
(请在此输入译文)<br />
'''原文链接:'''http://dx.doi.org/10.1016/j.econlet.2015.06.014<br />
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== Prediction of Cascading Failures in Spatial Networks ==<br />
From journals.plos.org<br />
April 28, 9:18 PM<br />
<br />
By Yang Shunkun, Zhang Jiaquan, Lu Dan<br />
(Translated by -)<br />
<br />
''Cascading overload failures are widely found in large-scale parallel systems and remain a major threat to system reliability; therefore, they are of great concern to maintainers and managers of different systems. Accurate cascading failure prediction can provide useful information to help control networks. However, for a large, gradually growing network with increasing complexity, it is often impractical to explore the behavior of a single node from the perspective of failure propagation. Fortunately, overload failures that propagate through a network exhibit certain spatial-temporal correlations, which allows the study of a group of nodes that share common spatial and temporal characteristics. Therefore, in this study, we seek to predict the failure rates of nodes in a given group using machine-learning methods. We simulated overload failure propagations in a weighted lattice network that start with a center attack and predicted the failure percentages of different groups of nodes that are separated by a given distance. The experimental results of a feedforward neural network (FNN), a recurrent neural network (RNN) and support vector regression (SVR) all show that these different models can accurately predict the similar behavior of nodes in a given group during cascading overload propagation.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153904<br />
<br />
== Competition between global and local online social networks ==<br />
From www.nature.com<br />
April 29, 2:58 PM<br />
<br />
By Kaj-Kolja Kleineberg & Marián Boguñá<br />
<br />
(Translated by -)<br />
<br />
''The overwhelming success of online social networks, the key actors in the Web 2.0 cosmos, has reshaped human interactions globally. To help understand the fundamental mechanisms which determine the fate of online social networks at the system level, we describe the digital world as a complex ecosystem of interacting networks. In this paper, we study the impact of heterogeneity in network fitnesses on the competition between an international network, such as Facebook, and local services. The higher fitness of international networks is induced by their ability to attract users from all over the world, which can then establish social interactions without the limitations of local networks. In other words, inter-country social ties lead to increased fitness of the international network. To study the competition between an international network and local ones, we construct a 1:1000 scale model of the digital world, consisting of the 80 countries with the most Internet users. Under certain conditions, this leads to the extinction of local networks; whereas under different conditions, local networks can persist and even dominate completely. In particular, our model suggests that, with the parameters that best reproduce the empirical overtake of Facebook, this overtake could have not taken place with a significant probabilit''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1038/srep25116<br />
<br />
== Bond Percolation on Multiplex Networks ==<br />
From journals.aps.org <br />
April 29, 7:20 PM<br />
<br />
By A. Hackett, D. Cellai, S. Gómez, A. Arenas, and J. P. Gleeson<br />
<br />
(Translated by -)<br />
<br />
''Modern society is permeated by systems with many numbers of nodes and connections (e.g., rail networks, airports). A theoretical study of the multiplex network consisting of European Union air routes and the London rail transportation system demonstrates the fragility of such a network.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1103/PhysRevX.6.021002<br />
<br />
== Broken detailed balance at mesoscopic scales in active biological systems ==<br />
From science.sciencemag.org <br />
April 29, 9:53 PM<br />
<br />
By CHRISTOPHER BATTLE, CHASE P. BROEDERSZ, NIKTA FAKHRI, VEIKKO F. GEYER, JONATHON HOWARD, CHRISTOPH F. SCHMIDT, FRED C. MACKINTOSH<br />
<br />
(Translated by -)<br />
<br />
''Systems in thermodynamic equilibrium are not only characterized by time-independent macroscopic properties, but also satisfy the principle of detailed balance in the transitions between microscopic configurations. Living systems function out of equilibrium and are characterized by directed fluxes through chemical states, which violate detailed balance at the molecular scale. Here we introduce a method to probe for broken detailed balance and demonstrate how such nonequilibrium dynamics are manifest at the mesosopic scale. The periodic beating of an isolated flagellum from Chlamydomonas reinhardtii exhibits probability flux in the phase space of shapes. With a model, we show how the breaking of detailed balance can also be quantified in stationary, nonequilibrium stochastic systems in the absence of periodic motion. We further demonstrate such broken detailed balance in the nonperiodic fluctuations of primary cilia of epithelial cells. Our analysis provides a general tool to identify nonequilibrium dynamics in cells and tissues.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1126/science.aac8167<br />
<br />
== Who's downloading pirated papers? Everyone ==<br />
From science.sciencemag.org <br />
April 29, 10:45 PM<br />
<br />
By John Bohannon<br />
(Translated by -)<br />
<br />
''In increasing numbers, researchers around the world are turning to Sci-Hub, the controversial website that hosts 50 million pirated papers and counting. Now, with server log data from Alexandra Elbakyan, the neuroscientist who created Sci-Hub in 2011 as a 22-year-old graduate student in Kazakhstan, Science addresses some basic questions: Who are Sci-Hub's users, where are they, and what are they reading? The Sci-Hub data provide the first detailed view of what is becoming the world's de facto open-access research library. Among the revelations that may surprise both fans and foes alike: Sci-Hub users are not limited to the developing world. Some critics of Sci-Hub have complained that many users can access the same papers through their libraries but turn to Sci-Hub instead—for convenience rather than necessity. The data provide some support for that claim. Over the 6 months leading up to March, Sci-Hub served up 28 million documents, with Iran, China, India, Russia, and the United States the leading requestors.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1126/science.352.6285.508<br />
<br />
== The Free Energy Requirements of Biological Organisms; Implications for Evolution ==<br />
From www.mdpi.com<br />
April 30, 4:34 AM<br />
<br />
By David H. Wolpert<br />
<br />
(Translated by -)<br />
<br />
''Recent advances in nonequilibrium statistical physics have provided unprecedented insight into the thermodynamics of dynamic processes. The author recently used these advances to extend Landauer’s semi-formal reasoning concerning the thermodynamics of bit erasure, to derive the minimal free energy required to implement an arbitrary computation. Here, I extend this analysis, deriving the minimal free energy required by an organism to run a given (stochastic) map π from its sensor inputs to its actuator outputs. I use this result to calculate the input-output map π of an organism that optimally trades off the free energy needed to run π with the phenotypic fitness that results from implementing π. I end with a general discussion of the limits imposed on the rate of the terrestrial biosphere’s information processing by the flux of sunlight on the Earth.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.3390/e18040138<br />
<br />
== From big data to important information ==<br />
From onlinelibrary.wiley.com<br />
April 30, 2:28 PM<br />
<br />
By Yaneer Bar-Yam<br />
(Translated by -)<br />
<br />
''Advances in science are being sought in newly available opportunities to collect massive quantities of data about complex systems. While key advances are being made in detailed mapping of systems, how to relate these data to solving many of the challenges facing humanity is unclear. The questions we often wish to address require identifying the impact of interventions on the system and that impact is not apparent in the detailed data that is available. Here, we review key concepts and motivate a general framework for building larger scale views of complex systems and for characterizing the importance of information in physical, biological, and social systems. We provide examples of its application to evolutionary biology with relevance to ecology, biodiversity, pandemics, and human lifespan, and in the context of social systems with relevance to ethnic violence, global food prices, and stock market panic. Framing scientific inquiry as an effort to determine what is important and unimportant is a means for advancing our understanding and addressing many practical concerns, such as economic development or treating disease.''<br />
<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://dx.doi.org/10.1002/cplx.21785<br />
<br />
== Explaining the Prevalence, Scaling and Variance of Urban Phenomena ==<br />
From arxiv.org<br />
April 30, 3:05 PM<br />
<br />
By Andres Gomez-Lievano, Oscar Patterson-Lomba, Ricardo Hausmann<br />
<br />
(Translated by -)<br />
<br />
''The prevalence of many urban phenomena changes systematically with population size. We propose a theory that unifies models of economic complexity and cultural evolution to derive urban scaling. The theory accounts for the difference in scaling exponents and average prevalence across phenomena, as well as the difference in the variance within phenomena across cities of similar size. The central ideas are that a number of necessary complementary factors must be simultaneously present for a phenomenon to occur, and that the diversity of factors is logarithmically related to population size. The model reveals that phenomena that require more factors will be less prevalent, scale more superlinearly and show larger variance across cities of similar size. The theory applies to data on education, employment, innovation, disease and crime, and it entails the ability to predict the prevalence of a phenomenon across cities, given information about the prevalence in a single city.''<br />
(请在此输入译文)<br />
<br />
'''原文链接:'''http://arxiv.org/abs/1604.07876<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91&diff=15171
复杂文摘翻译
2020-10-14T14:02:00Z
<p>Thingamabob:创建页面,内容为“复杂性文摘(Complexity Digest)是目前复杂性科学、复杂系统研究非常全面而权威的一个文摘索引。每周都收录了发表在各大国…”</p>
<hr />
<div>复杂性文摘(Complexity Digest)是目前复杂性科学、复杂系统研究非常全面而权威的一个文摘索引。每周都收录了发表在各大国际主流学术刊物上的最新文章摘要。还有关于最新会议、图书、讲座的介绍。我们将定期编译其中的部分摘要,并对其中优秀文章进行介绍。以向国内读者传播和推介复杂系统研究的最新进展。<br />
<br />
我们有大V唐璐、傅渥成、吴金闪和Jake坐镇;我们追踪以Complexity Digest为主的复杂系统科学进展;我们有英语专业人士进行翻译把关和指导;我们一起玩转复杂文摘。<br />
<br />
== 目录 ==<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%B8%80%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.6%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第一期-(摘自Complex Digest 2016.6月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%BA%8C%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.5%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第二期-(摘自Complex Digest 2016.5月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%B8%89%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.4%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第三期-(摘自Complex Digest 2016.4月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E5%9B%9B%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.3%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第四期-(摘自Complex Digest 2016.3月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E4%BA%94%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.2%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第五期-(摘自Complex Digest 2016.2月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/%E5%A4%8D%E6%9D%82%E6%96%87%E6%91%98%E7%BF%BB%E8%AF%91%E7%AC%AC%E5%85%AD%E6%9C%9F%EF%BC%8D(%E6%91%98%E8%87%AAComplex_Digest_2016.1%E6%9C%88%E6%96%87%E7%AB%A0) 复杂文摘翻译第六期-(摘自Complex Digest 2016.1月文章) ]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-The_Three-Body_Problem_and_beyond_—_a_Q%26A_with_Liu_Cixin 集智翻译-The Three-Body Problem and beyond — a Q&A with Liu Cixin ]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-Chinese_SF_and_the_art_of_translation_—_a_Q%26A_with_Ken_Liu 集智翻译-Chinese_SF_and_the_art_of_translation_—_a_Q%26A_with_Ken_Liu]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-How_artificial_intelligence_is_changing_economic_theory集智翻译-How_artificial_intelligence_is_changing_economic_theory 集智翻译-How_artificial_intelligence_is_changing_economic_theory]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-Big_Data_Fades_to_the_Algorithm_Economy 集智翻译-Big_Data_Fades_to_the_Algorithm_Economy]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-Economic_Reasoning_And_Artificial_Intelligence 集智翻译-Economic_Reasoning_And_Artificial_Intelligence]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-Anaconda与Jupyter_notebook_环境搭建与应用 集智翻译-Anaconda与Jupyter_notebook_环境搭建与应用]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-Cognitive_Machine_Learning(1):Learning_to_Explain 集智翻译-Cognitive_Machine_Learning(1):Learning_to_Explain]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-The_Unreasonable_Effectiveness_of_Recurrent_Neural_Networks 集智翻译-The_Unreasonable_Effectiveness_of_Recurrent_Neural_Networks]<br />
<br />
· [http://wiki.swarma.net/index.php/集智翻译-译友分享集锦 集智翻译-译友分享集锦]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%9F%BA%E4%BA%8E%E9%A9%AC%E5%B0%94%E7%A7%91%E5%A4%AB%E9%93%BE%E7%9A%84%E6%B5%81%E7%BD%91%E7%BB%9C%E5%88%86%E6%9E%90&diff=15170
基于马尔科夫链的流网络分析
2020-10-14T14:01:31Z
<p>Thingamabob:创建页面,内容为“一个平衡的流网络可以自然地转变成马尔科夫链,而马尔科夫链是数学家们研究得非常深入而透彻的数学对象,因此…”</p>
<hr />
<div>一个平衡的[[流网络]]可以自然地转变成[[马尔科夫链]],而[[马尔科夫链]]是数学家们研究得非常深入而透彻的数学对象,因此这为我们更好地分析[[流网络]]提供了便利条件。<br />
<br />
下面给出基本计算简表。定义:流矩阵F,对应的马尔科夫链矩阵M<br />
<br />
<math><br />
m_{ij}=\frac{f_{ij}}{\sum_{j=1}^{N+1}f_{ij}}<br />
</math>, 基础矩阵: <math><br />
U=I+M+M^2+\cdot\cdot\cdot=(I-M)^{-1}<br />
</math><br />
<br />
i到j的总流:<math><br />
t_{i,j}=T_0\frac{u_{0,i}u_{i,j}}{u_{i,i}}<br />
</math>, i到j的首达流:<math><br />
\phi_{i,j}=T_0 \frac{u_{0,i}u_{i,j}}{u_{i,i}u_{j,j}}<br />
</math><br />
<br />
其中T<sub>0</sub>为从源输入到整个网络的流量,也就是IS(参看[[流动网络]])。根据这两个公式,可以计算任意网络任意节点对的总流和首达流。<br />
<br />
i到j的平均时间:<math><br />
k_{i,j}=\frac{(MU^2)_{ij}}{(MU)_{ij}}<br />
</math>, i到j的首达平均时间:<math><br />
l_{i,j}=\frac{u_{jj}(M_{-j}U_{-j}^2)_{ij}}{u_{ij}}=\frac{(MU^2)_{ij}}{u_{ij}}-\frac{(MU^2)_{jj}}{u_{jj}}<br />
</math><br />
<br />
其中<math>M_{-j}</math>表示将M的第i行全置为0,<math>U_{-j}=I+M_{-j}+M_{-j}^{2}+\cdot\cdot\cdot=(I-M)^{-1}</math>。<br />
<br />
<br />
<br />
==从流网络到马尔科夫链的转换==<br />
<br />
[[File:exampleflownetwork.PNG|500px|framed|图1:一个示例流网络]]<br />
<br />
对于平衡流动来说,我们总可以将整个流系统看作是一个多粒子沿着网络流动的系统。例如,对于图1所示网络,当某个处于1号节点的粒子往外流动的时候,它可能会跳到2号节点,也可能会跳到3号节点。可以想到,由于1到2号节点的流量比到3号的节点大,所以这个粒子更有可能跳到2号节点。我们不妨假设粒子跳转到某个节点的概率是与这条边上的流量成正比的。也就是说,粒子会以5/8=50/80的概率从1跳到2,而以3/8=30/80的概率从1到3。同样的道理,当粒子跳入到任何一个节点后,它都会继续沿着边以概率跳转。<br />
<br />
我们可以写出这个网络所对应的流矩阵(参见[[流动网络]])如下:<br />
<br />
[[File:fluxmatrix.PNG||示例网络的流量矩阵]]<br />
<br />
其中,矩阵外围的数字为对节点的编码。0对应源,6对应汇。阴影区域对应网络的实线部分,为我们关注的节点主体。<br />
整个平衡态的流网络可以看作是一个马尔可夫链,其中每个节点相当于是粒子所处的可能状态,节点之间的跳转可以看作是概率转移。具体的,对于任何的处于平衡的流网络F,我们定义矩阵M为概率转移矩阵<ref name="finn">{{cite journal|last=Finn|first=John T.| title=Measures of Ecosystem Structure and Function Derived from Analysis of Flows|time=1976|journal = Journal of Theoretical Biology| volume = 56| pages = 363-380}}</ref>,其中M中的第i行第j列的元素就是粒子处于i状态下转移到j状态的概率,记为:<br />
<br />
<math><br />
m_{ij}=Pr\{to~~j|after~~visit~~i\}=\frac{f_{ij}}{\sum_{j=1}^{N+1}f_{ij}}<br />
</math><br />
<br />
当粒子进入汇节点N+1,它就不会再往外跳了,也就是说汇所在的行全为0,因此,状态N+1就相当于马尔可夫链的吸收态。注意,根据矩阵M的定义,它自然满足概率归一化条件(不包括汇节点):<br />
<br />
<math><br />
\sum_{j=1}^{N+1}m_{ij}=\frac{\sum_{j=1}^{N+1}f_{ij}}{\sum_{j=1}^{N+1}f_{ij}}=1,~~~~\forall i<N+1<br />
</math><br />
<br />
针对图1的示例网络,转化过来的马尔科夫矩阵为:<br />
<br />
[[File:markovmatrix.png|350px]]<br />
<br />
其中阴影部分为我们主要关心的马尔科夫转移概率。<br />
<br />
===逆向马尔可夫链===<br />
另外一个比较有趣的事实是,根据流矩阵F,我们还可以定义另外一个马尔科夫链M',称为逆向马尔科夫链<ref name="levine">{{cite journal|last=Levine|first=Stephen| title=Several Measures of Trophic Structure Applicable to Complex Food Webs|time=1980|journal = Journal of Theoretical Biology| volume = 83| pages = 195-207}}</ref>。它刻画的是一个逆向的因果过程,也就是说如果我在图1中2号节点观察到了一个新到的粒子,那么它有可能从1号节点过来也可能从3号节点过来。显然1到2的流量要比3到2的流量大得多,因此粒子从1跳过来的可能性会更大。那么,既然整个网络是平稳的,我们不难想到,在2号节点观测到一个粒子的条件下,它是从1号节点跳过来的概率是5/6=50/60,它从3号节点跳过来的概率是1/6=10/60。<br />
<br />
更一般地,我们定义逆向马尔科夫链M',其中任意的元素m'<sub>ij</sub>定义为:观察到粒子来到了节点i的条件下,它可能是从j节点流过来的概率。它按照下式计算:<br />
<br />
<math><br />
m'_{ij}=Pr\{from~~j|observed~~particle~~on~~i\}=\frac{f_{ji}}{\sum_{j=0}^{N}f_{ji}}<br />
</math><br />
<br />
同样地道理,它也是归一化的,即:<br />
<br />
<math><br />
\sum_{j=0}^{N}m'_{ji}=1,~~~~\forall i>0<br />
</math><br />
<br />
这个逆向马尔可夫链又可以看作是逆向流矩阵F<sup>T</sup>(即原始流矩阵F的转置)所对应的正向马尔科夫矩阵,这是因为:<br />
<br />
<math><br />
m'_{ij}=\frac{f_{ji}}{\sum_{j=0}^{N}f_{ji}}=\frac{F^T_{\{ij\}}}{\sum_{j=0}^{N}F^T_{\{ij\}}}=m_{ij}(F^T)<br />
</math><br />
<br />
其中逆向流矩阵就相当于把原始流网络所有的有向边都掉转方向,并保持所有的流量不变。由于网络是平衡的,所以逆向的流网络必然也是平衡的。<br />
<br />
这似乎给我们描绘了一个有趣的图景:在一个平衡的流网络中,所有的粒子都顺着流动从源到汇。而与此同时,如果我们从汇观察到粒子,并不断地询问这个粒子是从哪个节点跳转过来的,我们就得到了一个反向的信息流动,就仿佛是有假想的粒子从汇流到了源一样。<br />
<br />
==路径分析==<br />
<br />
下面,我们沿着粒子在流网络中流动,分析粒子所能经过的所有可能路径。让我们以图1所示网络为例,考察从1节点到4节点的路径。我们可以将所有从1到4的路径分成2类:从1到4的首达路径,以及包含了从4到4的循环路径。而对于首达路径,又可以分成2类:直接路径、首达流循环路径<ref name="higashi">{{cite journal|last=Higashi|first=Masahiko| title=Network trophic dynamics: the modes of energy utilization in ecosystems|time=1993|journal = Ecological Modelling| volume = 66| pages = 1-42}}</ref>。<br />
<br />
===首达路径===<br />
<br />
首先,我们可以列出从1到4的所有'''直接路径''',所谓的直接路径是指粒子从1流到4,路径上的所有节点只被访问一次(没有循环)的所有可能路径,对于这个简单的网络来说,我们可以直接列出这些路径是:<br />
<br />
<math><br />
1\rightarrow 2\rightarrow 4<br />
</math><br />
<br />
<math><br />
1\rightarrow 3\rightarrow 2\rightarrow 4<br />
</math><br />
<br />
其次,从1到4的'''首达流循环路径'''是指粒子从1流到4,中间允许任意次地循环重复经过某个节点,但是一旦到达4之后就不再循环重复的所有可能路径。也就是说,4节点只能唯一地出现在路径的尾端。对于图1所示的网络,我们知道1-->2-->5-->3-->2-->4是一条首达循环路径,而1-->2(-->5-->3-->2)(-->5-->3-->2)-->4也是一条首达循环路径,其中括号的部分被重复了两次。当然,括号部分中重复3次、4次…… 都是不同的首达循环路径。所以,我们可以把这一系列从5-->3-->2之间循环任意次的路径简记成<br />
<br />
<math><br />
1\rightarrow 2 (\rightarrow 5\rightarrow 3\rightarrow 2)^m\rightarrow 2\rightarrow 4<br />
</math><br />
<br />
其中,指数的意思为括号部分的路径字符可以重复m次,m为任意的整数(可以取无穷大),因此有无穷条从1到4的首达循环路径。<br />
<br />
值得指出的是,在这里,我们相当于定义了两个路径的乘法,如果路径P1=i1-->...-->i,路径P2=j1,....,j,则P1乘以P2定义为:<br />
<br />
<math><br />
P_1 \cdot P_2=i_1\rightarrow i_2 \rightarrow \cdot\cdot\cdot i \rightarrow j_1\rightarrow j_2\rightarrow \cdot\cdot\cdot j<br />
</math><br />
<br />
可以验证上述的路径平方就是我们定义的路径的乘法。<br />
<br />
同样的道理,还有一系列不同的从1到4的首达循环路径:<br />
<br />
综上所述,我们实际上可以把所有的从1到4的首达路径(包含了不循环的和循环的)统一表示成:<br />
<br />
<math><br />
1\rightarrow 2 (\rightarrow 5\rightarrow 3\rightarrow 2)^m\rightarrow 4,~~~~ <br />
1\rightarrow 3 (\rightarrow 2\rightarrow 5\rightarrow 3)^m\rightarrow 2\rightarrow 4<br />
</math><br />
<br />
其中m为大于等于0的任意整数。当m=0的时候,就是直接路径。<br />
<br />
===循环路径===<br />
<br />
第二大类路径是那些到了4号节点又沿着网络的流动重复到达4号节点的流动路径,它们就是'''循环路径''',例如:1-->2-->4-->5-->3-->2-->4,又如:1-->3-->2-->5-->3-->4-->5-->3-->2-->4。利用我们上面引入的记号,我们可以把这两个路径进行推广统一写为:<br />
<br />
<math><br />
[1\rightarrow 2 (\rightarrow 5\rightarrow 3\rightarrow 2)^m\rightarrow 4]\cdot[(\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^t</math><br />
<br />
<math><br />
[1\rightarrow 3 (\rightarrow 2\rightarrow 5\rightarrow 3)^m\rightarrow 2\rightarrow 4]\cdot [(\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^t<br />
</math><br />
<br />
其中m,m',t都是大于等于0的任意整数。我们看到,上式两种路径就是在所有可能的首达路径后面“后缀”了一个从4到4的首达路径的任意次方。如果我们再定义路径的'''加法'''为将两个相加的路径并列在一起(相当于集合的并集),则我们可以简洁统一地把从1到4的所有可能路径表达为:<br />
<br />
<math><br />
\sum_{m,m',t}{[1\rightarrow 2 (\rightarrow 5\rightarrow 3\rightarrow 2)^m \rightarrow 4]\cdot [(\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^t+ [1\rightarrow 3 (\rightarrow 2\rightarrow 5\rightarrow 3)^m\rightarrow 2\rightarrow 4]\cdot [(\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^{t}}<br />
</math><br />
<br />
可以验证路径的加法和乘法同样满足结合律,所以上式又可以写作:<br />
{{NumBlk|:|<br />
<math><br />
\sum_{m,m',t}{\{[1\rightarrow 2 (\rightarrow 5\rightarrow 3\rightarrow 2)^m ] + [1\rightarrow 3 (\rightarrow 2\rightarrow 5\rightarrow 3)^m\rightarrow 2]\}\cdot [(\rightarrow 4\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^{t}}<br />
</math><br />
|{{EquationRef|eq1}}}}<br />
<br />
对于这种简单的网络来说,要表达出所有从1到4的路径都已经如此复杂,当我们考虑更复杂的网络的时候,机械地列出所有路径就几乎是不可能的了。所以,我们必须找出一套更合理的方法。<br />
<br />
===路径矩阵===<br />
<br />
我们可以用矩阵来表示路径,这样,通过矩阵的乘积可以表示路径的合成。首先,根据原始网络的邻接矩阵,我们定义一个矩阵P:<br />
<br />
<math><br />
P_{ij}=\left\{\begin{array}{ll} i\rightarrow j & \mbox {if i,j connected}, \\<br />
0 &\mbox {else} \end{array}\right.<br />
</math><br />
<br />
也就是,如果i和j相邻,则在(i,j)的位置上放置i-->j,表示从i到j的路径。该矩阵就是路径矩阵。<br />
<br />
例如,图1所示网络的路径矩阵可以写为:<br />
<br />
<math><br />
P_1=\begin{pmatrix}<br />
0 &0\rightarrow 1&0 &0 &0 &0 &0 & \\<br />
0 &0 &1\rightarrow 2&1\rightarrow 3&0 &0 &0 & \\<br />
0 &0 &0 &0 &2\rightarrow 4&2\rightarrow 5&2\rightarrow 6& \\<br />
0 &0 &3\rightarrow 2&0 &0 &0 &3\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &4\rightarrow 5&4\rightarrow 6& \\<br />
0 &0 &0 &5\rightarrow 3&0 &0 &5\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &0 &0 & \\<br />
\end{pmatrix}<br />
</math><br />
<br />
下面我们来考虑路径矩阵的乘积。设路径矩阵P和Q乘积(它们都是n*n的方阵)得到R,则<br />
<br />
<math><br />
R_{ij}=\sum_{k}P_{ik}\cdot Q_{kj}<br />
</math><br />
<br />
也就是说,路径矩阵的乘积与普通矩阵一样。注意等式右侧的乘法对应路径的乘法,也就是如果<math>P_{ik}=i\rightarrow k, Q_{kj}=k\rightarrow j</math>,则:<math>P_{ik}\cdot Q_{kj}=i\rightarrow k\rightarrow j</math>,即把两个路径拼接在一起。<br />
<br />
这样P<sub>1</sub>自乘一次就得到:<br />
<br />
<math><br />
\begin{array}{ll}<br />
P_1^2=\begin{pmatrix}<br />
0 &0\rightarrow 1&0 &0 &0 &0 &0 & \\<br />
0 &0 &1\rightarrow 2&1\rightarrow 3&0 &0 &0 & \\<br />
0 &0 &0 &0 &2\rightarrow 4&2\rightarrow 5&2\rightarrow 6& \\<br />
0 &0 &3\rightarrow 2&0 &0 &0 &3\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &4\rightarrow 5&4\rightarrow 6& \\<br />
0 &0 &0 &5\rightarrow 3&0 &0 &5\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &0 &0 & \\<br />
\end{pmatrix}\cdot<br />
\begin{pmatrix}<br />
0 &0\rightarrow 1&0 &0 &0 &0 &0 & \\<br />
0 &0 &1\rightarrow 2&1\rightarrow 3&0 &0 &0 & \\<br />
0 &0 &0 &0 &2\rightarrow 4&2\rightarrow 5&2\rightarrow 6& \\<br />
0 &0 &3\rightarrow 2&0 &0 &0 &3\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &4\rightarrow 5&4\rightarrow 6& \\<br />
0 &0 &0 &5\rightarrow 3&0 &0 &5\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &0 &0 & \\<br />
\end{pmatrix}&\\<br />
=<br />
<br />
\begin{pmatrix}<br />
0 &0 &0\rightarrow 1\rightarrow 2&0\rightarrow 1\rightarrow 3 &0 &0 &0 & \\<br />
0 &0 &0 &1\rightarrow 3\rightarrow 2&1\rightarrow 2\rightarrow 4&1\rightarrow 2\rightarrow 5&(1\rightarrow 2\rightarrow 6)+(1\rightarrow 3\rightarrow 6)& \\<br />
0 &0 &0 &2\rightarrow 5\rightarrow 3&0&2\rightarrow 4\rightarrow 5&(2\rightarrow 4\rightarrow 6)+(2\rightarrow 5\rightarrow 6)& \\<br />
0 &0 &0 &0 &3\rightarrow 2\rightarrow 4&3\rightarrow 2\rightarrow 5&3\rightarrow 2\rightarrow 6& \\<br />
0 &0 &0 &4\rightarrow 5\rightarrow 3&0 &0 &4\rightarrow 5\rightarrow 6& \\<br />
0 &0 &5\rightarrow 3\rightarrow 2&0 &0 &0 &5\rightarrow 3\rightarrow 6& \\<br />
0 &0 &0 &0 &0 &0 \\<br />
\end{pmatrix}<br />
&\end{array}<br />
<br />
</math><br />
<br />
其中i,j元素表示从i到j长度为2的所有路径。同样的道理,我们可以计算P<sub>1</sub><sup>m</sup>,它的任意元素就表示从i到j长度为m的所有可能路径。从这点来看,矩阵的乘积与路径的合成有着天然的对应。<br />
<br />
===全路径===<br />
<br />
接下来我们就要利用路径矩阵这个工具计算从任意节点i到任意节点j的所有可能路径。我们知道P<sup>m</sup>的第i,j个元素包括了从i到j的长度为m的可能路径,那么要得到从i到j的所有可能路径(无论路径有多长),我们只要把所有的P<sup>1</sup>、P<sup>2</sup>……P<sup>m</sup>……加起来就可以了。所以:<br />
<br />
<math><br />
Paths\{i\rightarrow j\}=(\sum_{m=1}^{\infty}P^m)_{ij}<br />
</math><br />
<br />
例如,对于图1的网络,1到4的所有可能路径就是:<br />
<br />
<math><br />
Paths\{1\rightarrow 4\}=(\sum_{m=1}^{\infty}P_1^m)_{1,4}<br />
</math><br />
<br />
如果我们把P<sub>1</sub>代入到上式,可以验证它跟我们在{{EquationNote|eq1}}中得到的全路径的表达式是一样的。<br />
<br />
除此之外,我们也可以写出所有从i到j的首达路径(j在整个路径中只能出现在结尾)为:<br />
<br />
<math><br />
First\{i\rightarrow j\}=\frac{(\sum_{m=1}^{\infty}P^m)_{i,j}}{(\sum_{m=1}^{\infty}P^m)_{j,j}}<br />
</math><br />
<br />
这里,两个路径相除定义为乘法的逆运算。即,如果<math>R\cdot Q=P</math>,则定义<math>\frac{P}{Q}=R</math>。例如,若<math>P=1\rightarrow 2\rightarrow 3\rightarrow 4, Q=3\rightarrow 4</math>, 则<math>\frac{P}{Q}=1\rightarrow 2</math><br />
<br />
我们可以写出图1中所有从1到4的首达路径为:<br />
<br />
<math><br />
First\{1\rightarrow 4\}=\frac{(\sum_{m=1}^{\infty}P_1^m)_{1,4}}{(\sum_{m=1}^{\infty}P_1^m)_{4,4}}<br />
</math><br />
<br />
根据{{EquationNote|eq1}},我们知道所有的首达路径拼接上(乘上)任意一条从4到4的路径就构成了一条非首达路径,那么我们将所有的路径除以一条从4到4的路径就可以得到首达路径了。也就是在{{EquationNote|eq1}}中将<math>[(\rightarrow 5\rightarrow 3\rightarrow 2)^{m'+1}\rightarrow 4]^{t}</math>这个因子除去。<br />
<br />
==流量分析==<br />
<br />
===总流量===<br />
<br />
我们知道,每一条从i到j的路径就代表了粒子从i到j的一种可能流动。当有大量的粒子在体系中流动的时候,每条路径上都会分配一定的流量。下面,我们就要求出从i到j经过所有可能路径的粒子总流量<math>t_{i,j}</math>。这个流量可以通过这样的假想实验来定义:假设原始的粒子没有颜色,而粒子一旦经过节点i就被染成了红色,并且一直保持不褪色。那么,我从j节点处统计:每一时刻流入j节点的红色粒子数有多少?这个数量就相当于从i到j的总流量:<math>t_{i,j}</math>。<br />
<br />
如果从i到j的所有路径中不存在着循环,如下图所示的树状结构:<br />
<br />
[[File:simpletreeill.PNG|300px]]<br />
<br />
我们很容易计算出从1到4的总流量为:<br />
<br />
<math><br />
t_{1,4}=50\times \frac{3}{5}\times \frac{2}{3}=20=T_1 (M+M^2)_{1,4}<br />
</math><br />
<br />
即1节点的总流量乘以经过一步概率转移从1到4的概率,再加上总流量乘以经过2步概率转移从1到4的概率。然而,当网络中存在着循环结构的时候,计算稍微麻烦,但是我们不妨将上面通过马尔科夫链计算的公式推广到有环的结构上,也就是对M的m次方求和一直进行下去,直到无穷大。例如,对于如图1所示的流网络,从1到4的总流量为:<br />
<br />
<math><br />
t_{1,4}=T_1 (\sum_{k=1}^{\infty}M^k)_{1,4}<br />
</math><br />
<br />
这里,T<sub>1</sub>为从源到1的流量,等于80。我们知道M<sub>1,4</sub>表示粒子直接从1到4的转移概率,这样T<sub>1</sub>M<sub>1,4</sub>就是粒子经过一步转移从1到4的流量。同样,<math>(M^2)_{1,4}</math>表示粒子经过两步转移从1到4的转移概率,那么<math>T_1(M^2)_{1,4}</math>就是粒子经过2步转移从1到4的流量。……,我们将经过1步转移、2步转移、……从1到4的粒子流总量加起来自然就是从1到4的粒子流量。<br />
<br />
====基础矩阵====<br />
<br />
然而,上式不方便计算,因为存在着矩阵的无穷级数和。注意到,M是一个行列式小于1的方阵,因此,我们可以用下列矩阵级数的求和公式:<br />
<br />
<math><br />
(\sum_{m=1}^{\infty}M^m)_{1,4}=\frac{M}{I-M}<br />
</math><br />
<br />
这里I是与M同样维度的单位阵。矩阵的无穷等比数列之和与数的无穷等比数列和的计算一模一样。我们定义:<br />
<br />
<br />
<math><br />
U=\frac{1}{I-M}=(I-M)^{-1}<br />
</math><br />
<br />
为'''基础矩阵'''(Fundamental Matrix),这沿袭了[[投入产出分析]]的用法。<math>(I-M)^{-1}</math>表示矩阵I-M的逆。在这个例子中,U可以写出来:<br />
<br />
<math><br />
\left(<br />
\begin{array}{ccccccc}<br />
1 & 1 & \frac{3}{4} & \frac{7}{16} & \frac{1}{4} & \frac{1}{2} & 1 \\<br />
0 & 1 & \frac{3}{4} & \frac{7}{16} & \frac{1}{4} & \frac{1}{2} & 1 \\<br />
0 & 0 & \frac{42}{41} & \frac{7}{82} & \frac{14}{41} & \frac{28}{41} & 1 \\<br />
0 & 0 & \frac{12}{41} & \frac{42}{41} & \frac{4}{41} & \frac{8}{41} & 1 \\<br />
0 & 0 & \frac{3}{164} & \frac{21}{328} & \frac{165}{164} & \frac{21}{41} & 1 \\<br />
0 & 0 & \frac{3}{82} & \frac{21}{164} & \frac{1}{82} & \frac{42}{41} & 1 \\<br />
0 & 0 & 0 & 0 & 0 & 0 & 1<br />
\end{array}<br />
\right)<br />
</math><br />
<br />
====总流量====<br />
<br />
于是,将数字代入,从1到4的总流就是:<br />
<br />
<math><br />
t_{1,4}=T_1 (MU)_{1,4}=80\times \frac{1}{5}=16<br />
</math><br />
<br />
下面,我们再来计算从2到4的总流量。按照上面的类似计算,我们可以得到:<br />
<br />
<math><br />
t_{2,4}=T_2 (MU)_{2,4}=60\times \frac{14}{41}=20.4878<br />
</math><br />
<br />
然而,从图1中,我们看到从2到4的路径只有一条2-->4,所以从1到4的流量直观地看应该是20,而我们上面计算的结果却比20大。为什么呢?仔细分析会发现,原因出在,对于2号节点的总流量T<sub>2</sub>包含着从2到4又循环回2的流量(从3到2的那部分流量)。而这部分流量又在U矩阵中被重复计算了。所以,要把它刨除掉。即只计算从0节点经过1流过来流量50,该流量就称为从源0到2的首达流。如果所有粒子都是无色的,而只有经过2号节点的粒子被染成红色,并且永不褪色,那么,从0到2的首达流就是:<br />
<br />
<math><br />
\phi_{0,2}=50+30\times \frac{2}{7}=\frac{410}{7}<br />
</math><br />
<br />
不难看出,无色粒子可能从1直接到2,也可能经过3到2。至于首达流的更一般的计算将放到下一节讨论。<br />
<br />
<math><br />
t_{2,4}=\phi_{0,2} (MU)_{2,4}=\frac{410}{7}\times \frac{14}{41}=20<br />
</math><br />
<br />
这样的计算才可以得到正确的结果。因此,任意点i到j的总流量应该按下式计算:<br />
<br />
<math><br />
t_{ij}=\phi_{0,i} (MU)_{ij}<br />
</math><br />
<br />
<br />
<br />
根据上述公式,从i到i自己的总流量也就应该是:<math><br />
t_{ii}=\phi_{0,i} (MU)_{ii}<br />
</math><br />
然而,这个式子并不完全。因为,它并不包括流<math>\phi_{0i}</math>自身。习惯上,我们定义从i到i的总流应该包括<math>\phi_{0i}</math>。<br />
因此,写完全应该是:<br />
<br />
<math><br />
t_{ii}=\phi_{0,i} ((MU)_{ii}+1)<br />
</math>。<br />
<br />
注意到,根据U的定义,<math>MU=U-I</math>,所以 <br />
<br />
<math><br />
t_{ii}=\phi_{0,i} (U)_{ii}<br />
</math>。<br />
<br />
<br />
<br />
最后,综合上述所有讨论,从i到j的总流量应该按照下式计算:<br />
<br />
<math><br />
t_{ij}=\phi_{0,i}(U)_{ij}<br />
</math><br />
<br />
即使对于i不等于j的情况上式也成立,因为U的非对角元与MU的非对角元相同。<br />
<br />
===首达流===<br />
<br />
上面的讨论中曾引出了首达流的概念,下面我们就来讨论一般地从i到j的首达流应该怎样计算。首先,我们定义从i到j的首达流为所有从i出发首次到达j的粒子总流量。还是假设所有的粒子经过i节点后被染成红色,并且同时假设粒子一旦经过j后,我们就把红色涂掉,那么每一时刻到达j的红色粒子总数就是从i到j的首达流。这样,所有经过i到达j的粒子就可以分成2类:'''首达流'''和'''循环流'',它们的总和就是总流动。<br />
<br />
例如,对于图1来说,从1到4的总流动可以分为首达流和循环流:<br />
<br />
<math><br />
t_{1,4}=\phi_{1,4}+\psi_{1,4}<br />
</math><br />
<br />
我们已经知道t<sub>1,4</sub>的计算了,如果我们会计算ψ<sub>1,4</sub>的话,就很容易求出首达流了。所谓的从1到4的循环流一定是那些曾经至少已经经过一次4号节点的粒子所构成的流动。而我们知道,所有已经经过4号节点的粒子一定是那些首次到达了4号节点的粒子又重新从4出发,沿着所有可能路径再流回到4节点的粒子。这些粒子的路径就是如{{EquationNote|eq1}}式中所描述的,并且t不为0。同样的,根据流量与路径的关系,我们可以计算出:<br />
<br />
<math><br />
\psi_{1,4}=\phi_{1,4}(\sum_{m=1}^{\infty}M^m)_{4,4}<br />
</math><br />
<br />
也就是1到4的首达流再经过所有可能路径回到4的总流量。这样,我们就有:<br />
<br />
<math><br />
t_{1,4}=\phi_{1,4}+\psi_{1,4}=\phi_{1,4}+\phi_{1,4}(\sum_{m=1}^{\infty}M^m)_{4,4}=\phi_{1,4}(1+(\sum_{m=1}^{\infty}M^m)_{4,4})=\phi_{1,4}u_{4,4}<br />
</math><br />
<br />
其中,u<sub>4,4</sub>表示(U)<sub>4,4</sub><br />
这样就可以求出1到4的首达流:<br />
<br />
<math><br />
\phi_{1,4}=\frac{t_{1,4}}{u_{4,4}}<br />
</math><br />
<br />
我们定义,当i=j的时候:<br />
<br />
<math><br />
\phi_{i,i}=T_i<br />
</math><br />
<br />
而我们已经知道了t<sub>1,4</sub>的表达式,因此1到4的首达流可以计算出,等于16*165/164=660/41。<br />
<br />
上述方法适用于更一般的网络,因此,我们可以得到计算任一点i到j首达流的正确计算公式为:<br />
<br />
<math><br />
\phi_{i,j}=\frac{t_{i,j}}{u_{j,j}}<br />
</math><br />
<br />
===小结===<br />
<br />
总结来看,我们这里定义了从i到j的两种流动:i到j的'''总流'''和i到j的'''首达流'''。如果将经过i节点的粒子染色,则总流就是每个时刻j节点接收到的红色粒子总数,而首达流就是所有那些第一次经过j节点的红色粒子总数。它们的计算方式如下:<br />
<br />
总流:<br />
<br />
<math><br />
t_{i,j}=\phi_{0,i}u_{i,j}=\frac{t_{0,i}}{u_{i,i}}u_{i,j}=T_0\frac{u_{0,i}u_{i,j}}{u_{i,i}}<br />
</math><br />
<br />
首达流:<br />
<br />
<math><br />
\phi_{i,j}=\frac{t_{i,j}}{u_{j,j}}=T_0 \frac{u_{0,i}u_{i,j}}{u_{i,i}u_{j,j}}<br />
</math><br />
<br />
其中T<sub>0</sub>为从源输入到整个网络的流量,也就是IS(参看[[流动网络]])。根据这两个公式,可以计算任意网络任意节点对的总流和首达流。<br />
<br />
我们看到,无论是总流还是首达流,都要用到U矩阵,而<br />
<br />
<math><br />
U=I+M+M^2+\cdot\cdot\cdot+M^{\infty}<br />
</math><br />
<br />
相当于包含了所有从i到j的一步转移概率、2步转移概率、3步转移概率……。但注意,u<sub>ij</sub>并不是概率,因为u可能大于1。即便它不大于1,也要注意到M、M<sup>2</sup>, ……矩阵每一行都是归一化的,所以把它们加起来就不再满足归一化条件(无论对于行还是列)。所以,u<sub>ij</sub>并不表示从i到j的概率,而是表示i对j的'''总影响'''(Impact)。这是一个很含糊的概念,但目前也只能这样来解释U了。<br />
<br />
而当u<sub>ij</sub>乘以了一个流量φ<sub>i</sub>,则所得的矩阵的每一个元素就有了明确的意义:表示从i到j的总流量。这个流量虽然从定义上看是一个瞬时t,i到j的粒子总数,但是根据计算式,它实际上是把t时刻的0步转移、t-1时刻的一步转移、t-2时刻的2步转移,……,所有时间步的粒子数加起来。由于流网络是平衡的,所以马尔科夫链是平稳的,所以我们可以把瞬时空间上的流量转变成所有历史的求和,这一点是最让人吃惊的事实。<br />
<br />
==平均时间(距离)==<br />
<br />
前面研究的是流量,下面我们研究与时间相关的主题。大量的粒子从网络中流动,我们假设单位时间粒子沿着有向连边跳转。这样,粒子需要m个时间步才能走完一条m长的路径。下面,我们将研究从网络上任意一点i到任意一点j的时间(距离)。<br />
<br />
首先,由于网络中存在着环路,因此,从i流向j的粒子有可能经历无限长的时间步。为了避免这个问题,我们只考虑首达时间,也就是粒子从i出发第一次到达j的时间。但是,由于粒子可能沿不同的路径到达j,而这些路径的长度又不一样,所以没有确定的首达时间值。于是,我们只能用这些粒子的首达时间值来作为我们研究的目标,也就是平均首达时间。有趣的是,对于平衡的流网络来说,平均首达时间的计算存在着简洁而明确的表达式和计算方法。<br />
<br />
===任意点i到汇的平均时间===<br />
<br />
首先,我们来求从任意节点i(不包括汇)出发,到达汇N+1的粒子们的平均首达时间。由于到达N+1的粒子不再流向任何其它节点,因此这个平均首达时间其实就是粒子从i到达N+1的平均时间。下面,我们来计算从i到汇的平均时间。<br />
<br />
我们不妨假设从任意节点i到达汇N+1的平均时间为l<sub>i</sub>,那么,我们可以列出如下等式:<br />
{{NumBlk|:|<br />
<math><br />
l_i=1+\sum_{j=0}^{N}{m_{ij}l_j}, ~~~~\forall i\neq N+1<br />
</math><br />
|{{EquationRef|eq2}}}}<br />
<br />
下面来解释这个式子。我们知道任何粒子要想跳到汇都有两种可能性:直接跳到N+1,或者先跳到任意一个其他的非汇节点j,然后再跳到汇N+1。对于第一种情况,它的路径长度确定性的是1,发生概率是<math>m_{i,N+1}</math>。而对于第二种情况,假设粒子跳到了j,再由j跳到N+1,那么我们知道粒子从j跳到N+1的平均首达时间是l<sub>j</sub>,而粒子跳转到j的概率是m<sub>i,j</sub>,因此粒子跳到任意的非汇节点,再跳到汇的平均路径长度就是<math>\sum_{j=0}^{N}{m_{ij}(1+l_j)}</math>,其中和号里的式子加1的原因是每条路经长度都要包含从i跳到j的这一步。于是,把这两种可能性合起来就有:<br />
<br />
<math><br />
l_i=m_{i,N+1}\cdot 1+\sum_{j=0}^{N}{m_{ij}(1+l_j)}=m_{i,N+1}+\sum_{j=0}^{N}m_{ij}+\sum_{j=0}^{N}m_{ij}l_j=1+\sum_{j=0}^{N}m_{ij}l_j, ~~~~\forall i\neq N+1<br />
</math><br />
<br />
最后用到了马尔科夫链的归一化条件:<math>\sum_{j=0}^{N+1}m_{ij}=1</math>。注意到{{EquationNote|eq2}}实际上是一个线性方程组,未知数有N+1个,方程个数也有N+1个,可以直接求解。事实上,如果我们定义:向量<math>L=(l_0,l_1,\cdot\cdot\cdot,l_N)^T</math>,则{{EquationNote|eq2}}可以写成矩阵的形式:<br />
<br />
<br />
<math><br />
L=\mu+M_{-(N+1)} L <br />
</math><br />
<br />
<br />
其中<math>\mu=(1,1,\cdot\cdot\cdot,1)^T</math>,1构成的N+1维列向量。<math>M_{-(N+1)}</math>表示原始马尔科夫矩阵去掉最后一行和最后一列。则,最终L可以解出:<br />
<br />
<br />
{{NumBlk|:|<br />
<math><br />
L=(I-M_{-(N+1)}^{-1})\cdot \mu=U_{-(N+1)}\cdot \mu=(\sum_{j=0}^{N}u_{ij})_{(N+1)\times 1}<br />
</math><br />
|{{EquationRef|eq3}}}}<br />
<br />
<br />
其中矩阵U<sub>-(N+1)</sub>为U矩阵去掉最后一行和最后一列。最后一个等式是根据[[马尔科夫链删除节点的性质]]中的定理1得到的。这样L中的第i个元素就是i节点到汇的平均时间。<br />
<br />
对于图1所示网络,我们可以计算出<math>L=(63/16, 47/16, 175/82, 66/41, 525/328, 197/164)</math>,其中从源到汇的平均路首达时间是63/16,也就是平均每个粒子经过3.9375步跳出整个网络。它刚好是<math>\sum_{j=0}^{N}u_{0j}=\frac{C_0}{T_0}+1=\frac{TST}{IS}+1</math>。这后两个等式需要参考[[流网络的异速标度律]].<br />
<br />
===从源到任意点i的平均首达时间===<br />
<br />
我们无法简单套用公式{{EquationNote|eq3}}来计算从源到任意点i的平均首达时间<ref name="levine"/>,这是因为如果将i节点去除,而非N+1,那么整个网络就有可能不连通,使得最后的求解出现问题。但是,我们仍然可以用类似的推理方法:我们假设0到任意i的平均首达时间为l<sub>i</sub>。从源0到任意节点i的路径总可以分成两种情况,要么从0直接到i,要么从0到某个j再到i,于是假设0到j的距离为l<sub>j</sub>,则第二种情况下的平均首达时间就是:<math>\sum_{j=1}^{N+1} m'_{ji}(l_j+1)</math>。注意,在这里,马尔科夫转移概率是逆向马尔科夫转移概率m'<sub>ji</sub>而不再是m了,这是因为我们已经确定性地知道了粒子肯定到达i的情况下,它可能从j节点过来的概率。于是,在这种情况下,概率归一化的对象是给定在i观察到粒子的情况下,从所有可能的中间节点过来的概率。所以,如果使用m<sub>ji</sub>的话,则不能满足概率归一的条件,所以只能用m'<sub>ij</sub>。最后,再综合第一种情况,就有:<br />
<br />
<math><br />
l_i=m'_{0,i}+\sum_{j=1}^{N+1} m'_{ji}(l_j+1)=m'_{0,i}+\sum_{j=1}^{N+1} m'_{ji}+\sum_{j=1}^{N+1} m'_{ji}l_j=1+\sum_{j=1}^{N+1}m'_{ji}l_j,~~~~\forall i\neq 0<br />
</math><br />
<br />
同样可以把它写作一个矩阵方程:<br />
<br />
<math><br />
L=\mu+M'_{-0}L<br />
</math><br />
<br />
于是,求解得:<br />
<br />
<math><br />
L=(I-M'_{-0})^{-1}\mu=U'_{-0}\mu<br />
</math><br />
<br />
注意,与{{EquationNote|eq3}}相比,我们把M换成了逆向马尔科夫矩阵M'。也就是说,求从源0到任意点i的首达时间问题相当于是把整个流网络倒转过来,把源当成汇,把汇当成源,然后求任意节点i到汇的首达时间问题。<br />
<br />
对于图1所示网络,可以计算出:<br />
<math>L'=(1, 365/164, 193/82, 529/164, 285/82, 63/16)</math><br />
注意,第一个元素对应的是0到1的平均首达时间,……,以此类推。那么0到汇的平均首达时间是63/16,这与上面的计算结果是一致的。<br />
<br />
===任意节点i到任意节点j的平均首达时间===<br />
<br />
更一般地,我们应如何求出任意点i到j的平均首达时间呢?首先,我们需要明确这个平均首达时间到底是什么意思。还是假设所有流经i点的粒子都被染上了红色,并且粒子一经过j点就被抹掉红色。这样,j点接收的粒子就是首次到达j点的粒子。同时,假设每个粒子都有一个内置的秒表。它一旦被染成红色,秒表就开始计时,每个时间步走动一次。于是我们在j点读出粒子的计时,看它从i出发走了多少时间步过来。由于每个粒子的时间不一样,于是,我们就可以求出一个均值。这就是我们要求的平均首达时间。<br />
<br />
如何计算这个平均首达时间呢?上面介绍的方法只适用于源或汇,而不能简单地拓展到非源或汇节点。下面,我们将介绍一种非常简单实用的方法,我称其为级数法。首先,根据平均首达时间的定义,我们知道从i到j的平均首达时间可以写为:<br />
<br />
<math><br />
l_{i,j}=\sum_{k=1}^{\infty}kp^{k}_{i,j}<br />
</math><br />
<br />
这里,p<sup>k</sup><sub>i,j</sub>是粒子经过k步从i首达j的概率。这个概率怎么求呢?一种直观的想法就是用(M<sup>k</sup>)<sub>i,j</sub>来计算这个数值。但是,这是错误的,因为,p<sup>k</sup><sub>i,j</sub>这个概率是指所有那些从i到j首达的粒子中,刚好经过了k步的粒子比例。而(M<sup>k</sup>)<sub>i,j</sub>表达的则是,在所有从i出发经过k步转移后的粒子中,那些刚好到达节点j的粒子比例。这两者显然不一样,因为从i出发的粒子经过k步后不见得都到达j。<br />
<br />
让我们只考察到达j的那些粒子,每一时刻,这个流量是固定的,有一些粒子是从i出发首达的粒子,而其中有一部分刚好经历了k步。那么,从i到j的首达粒子就可以用首达流来计算。刚好经过了k步的首达粒子如何计算呢?我们知道Φ<sub>0,i</sub>(M<sup>k</sup>)<sub>i,j</sub>是所有经过k步转移,从i到j的粒子数。但是这些粒子并不是首达粒子,有一些曾到过j又从j到j的粒子数。为了避免这种重复,我们不妨在M上做一些手脚:我们把M中j节点对应的行都设为0,即,定义:<br />
<br />
<math><br />
(M_{-j})_{p,q}=\left\{\begin{array}{ll} m_{p,q} & \mbox {if } p\neq j, \\<br />
0 & \mbox {if } p = j\end{array}\right.<br />
</math><br />
<br />
这样,概率p<sup>k</sup><sub>i,j</sub>就可以这样计算:<br />
<br />
<math><br />
p^{k}_{i,j}=\frac{\phi_{0i}(M_{-j}^k)_{i,j}}{\phi_{i,j}}<br />
</math><br />
<br />
于是平均首达时间就变成了求下列无穷级数和:<br />
<br />
<math><br />
l_{i,j}=\sum_{k=0}^{\infty}k\frac{\phi_{0i}(M_{-j}^k)_{i,j}}{\phi_{i,j}}=\frac{\phi_{0i}(\sum_{k=1}^{\infty}kM_{-j}^k)_{ij}}{\phi_{i,j}}<br />
</math><br />
<br />
那么,下面的任务就是如何求解无穷级数<math>\sum_{k=1}^{\infty}k(M_{-j})^k</math>的和。为此,我们设此和为X,则在等式两边右乘以M<sub>-j</sub>得到:<br />
<br />
<math><br />
XM_{-j}=\sum_{k=1}^{\infty}kM_{-j}^{k+1}=M_{-j}^2+2M_{-j}^3+\cdot\cdot\cdot<br />
</math><br />
<br />
与等式<math>X=M_{-j}+2M_{-j}^2+3M_{-j}^3+\cdot\cdot\cdot</math>相减得到:<br />
<br />
<math><br />
XM_{-j}-X=-(M_{-j}+M_{-j}^2+M_{-j}^3+\cdot\cdot\cdot)=-M_{-j}U_{-j}<br />
</math><br />
<br />
于是,解出:<br />
<br />
<math><br />
X=M_{-j}U_{-j}^2<br />
</math><br />
<br />
其中,<math>U_{-j}=\sum_{k=0}^{\infty}M_{-j}^k=(I-M_{-j})^{-1}</math><br />
所以,i到j的平均首达时间就是:<br />
<br />
<br />
<math><br />
l_{i,j}=\frac{\phi_{0i}(M_{-j}U_{-j}^2)_{ij}}{\phi_{i,j}}=\frac{\phi_{0i}(M_{-j}U_{-j}^2)_{ij}}{\frac{\phi_{0i}u_{ij}}{u_{jj}}}=\frac{u_{jj}(M_{-j}U_{-j}^2)_{ij}}{u_{ij}}<br />
</math><br />
<br />
又根据[[马尔科夫链删除节点的性质]],我们可以把上式简化为:<br />
<br />
<br />
<math><br />
l_{i,j}=\frac{u_{jj}(M_{-j}U_{-j}^2)_{ij}}{u_{ij}}=\frac{(MU^2)_{ij}}{u_{ij}}-\frac{(MU^2)_{jj}}{u_{jj}}<br />
</math><br />
<br />
<br />
<br />
于是我们得到了从任意节点i到j的平均首达时间计算公式。将这个公式套用到图1所示的网络上,我们可以得到从任意点i到j的平均首达时间,这就构成了平均首达时间矩阵:<br />
<br />
<math>L=<br />
\left(<br />
\begin{array}{ccccccc}<br />
0 & 1 & 88/41 & 373/164 & 7218/2255 & 557/164 &<br />
63/16 \\<br />
\infty & 0 & 47/41 & 209/164 & 4963/2255 &<br />
393/164 & 47/16 \\<br />
\infty & \infty & 0 & 9/4 & 58/55 & 5/4 & 175/82<br />
\\<br />
\infty & \infty & 1 & 0 & 113/55 & 9/4 & 66/41 \\<br />
\infty & \infty & 3 & 2 & 0 & 1 & 525/328 \\<br />
\infty & \infty & 2 & 1 & 168/55 & 0 & 197/164 \\<br />
\infty & \infty & \infty & \infty & \infty & \infty & 0<br />
\end{array}<br />
\right)<br />
</math><br />
<br />
我们看到,这与前面计算的从0到所有点,以及从所有点到汇的距离是一致的,这进一步验证了这个方法的正确性。<br />
<br />
===平均时间===<br />
<br />
根据上述级数法求解平均首达时间的启发,我们还可以求出从任意点i到达任意点j的平均时间而非平均首达时间。这里,平均时间按照如下方式定义:所有经过i的节点染成红色,并且永不退色,而且,经过i的粒子就开启一个计时器,则从j点处统计红色粒子,计算它们计时器所经历的时间。<br />
<br />
有趣的是,按照上述方法,这个平均时间比平均首达时间更容易计算。还是按照平均时间的定义:<br />
<br />
<math><br />
k_{i,j}=\sum_{k=1}^{\infty}kp^{k}_{i,j}<br />
</math><br />
<br />
这里<math>p^{k}_{i,j}</math>的计算不用再考虑首达问题,于是<br />
<br />
<math>p^{k}_{i,j}=\frac{\phi_{0i}(M^k)_{i,j}}{T'_{i,j}}</math><br />
<br />
这里,<math>T'_{i,j}</math>应为从i到j的总流。理应代入前面得到的关于<math>T_{i,j}</math>的表达式。这大体上正确,只有在i=j的时候不正确。因为在<math>T_{i,i}</math>中包含了从0到i的首达流<math>\phi_{0,i}</math>,而在平均时间的计算中,这部分流量不应包含,故而<math>T'_{i,i}=T_{i,i}-1</math>。所以:<br />
<br />
<math><br />
T'_{i,j}=\phi_{0,i}(MU)_{ij}<br />
</math><br />
<br />
从而时间:<br />
<br />
<math><br />
p_{i,j}^k=\frac{(M^k)_{i,j}}{(MU)_{ij}}<br />
</math><br />
<br />
所以,平均时间的计算公式为:<br />
<br />
<br />
<math><br />
k_{i,j}=\frac{(MU^2)_{ij}}{(MU)_{ij}}<br />
</math><br />
<br />
<br />
根据这个公式,计算图1所示网络,得到彼此平均时间的矩阵为:<br />
<br />
<math><br />
K=<br />
\left(<br />
\begin{array}{ccccccc}<br />
\infty & 1 & 365/164 & 193/82 & 529/164 & 285/82 &<br />
63/16 \\<br />
\infty & \infty & 201/164 & 111/82 & 365/164 & 203/82<br />
& 47/16 \\<br />
\infty & \infty & 273/82 & 191/82 & 177/164 &<br />
109/82 & 175/82 \\<br />
\infty & \infty & 177/164 & 273/82 & 341/164 &<br />
191/82 & 66/41 \\<br />
\infty & \infty & 505/164 & 341/164 & 669/164 &<br />
177/164 & 525/328 \\<br />
\infty & \infty & 341/164 & 177/164 & 505/164 &<br />
273/82 & 197/164 \\<br />
\infty & \infty & \infty & \infty & \infty & \infty & \infty<br />
\end{array}<br />
\right)<br />
</math><br />
<br />
有趣地是,对角线元素表达的是节点i到i的平均回归时间,它可以用于节点i的中心度刻画。<br />
<br />
<math>k_{i,i}=(\infty,\infty,273/82,273/82,669/164,273/82,\infty)</math><br />
<br />
该数值越小,说明这个节点在整个网络中的流量循环也就越快。<br />
<br />
另外,我们还可以通过比较平均时间矩阵和平均首达时间矩阵,会发现任意两点之间的平均时间都比平均首达时间要大一些,通过做这两个矩阵的差,我们得到:<br />
<br />
<math><br />
K-L=<br />
\left(<br />
\begin{array}{ccccccc}<br />
& 0 & 13/164 & 13/164 & 223/9020 & 13/164 & 0 \\<br />
& & 13/164 & 13/164 & 223/9020 & 13/164 & 0 \\<br />
& & 273/82 & 13/164 & 223/9020 &13/164 & 0 \\<br />
& & 13/164 & 273/82 & 223/9020 &13/164 & 0 \\<br />
& & 13/164 & 13/164 & 669/164 &13/164 & 0 \\<br />
& & 13/164 & 13/164 & 223/9020 &273/82 & 0 \\<br />
& & & & & & <br />
\end{array}<br />
\right)<br />
</math><br />
<br />
观察这个矩阵,我们发现,所有有值的列除了对角线拥有相同的数值。这表明任何一点到达某一个点的平均时间与首达平均时间之差均为常数,并且出于同一环上的不同节点具有相同的数值,例如2,3,5。<br />
<br />
==参考文献==<br />
<br />
历史上,经济学家最早给出了U矩阵(也称为Leontief矩阵)的定义,请参照[[投入产出分析]]。后来生态学家Finn将这种分析方法引入到<ref name="finn"/>了生态流网络中用于分析能量流网络。Patten、Ulanowicz等人将这套方法系统化,提出了Environ理论<ref name="environ">{{cite journal | last = Patten| first = Bernard C.| date = 1982 | title = Environs: Relativistic elementary particles for ecology| journal = The American Naturalist| volume = 119| pages = 179-219}}</ref><ref>{{cite journal | last = Patten| first = Bernard C.| date = 1985 | title = Energy Cycling in the Ecosystem| journal = Ecological Modelling| volume = 28| pages =1-71}}</ref><ref>{{cite journal | last = Ulanowicz| first = Roberte E.| last2= Wolff | first2=Wilfried F.| date = 1990 | title = Ecosystem Flow Networks: Loaded Dice?| journal = Mathematical Biosciences| volume = 103| pages =45-68}}</ref>。随后,这些人又将这套方法进一步扩展以讨论能量流的循环与存储问题<ref>{{cite journal | last = Patten| first = Bernard C.| last2= Higashi| first2=Masahiko| last3= Burns | first2=Thomas P.| date = 1990 | title = Trophic Dynamics in Ecosystem Networks: Significance of Cycles and Storage| journal = Ecological Modelling| volume = 51| pages =41-28}}</ref>以及能量流的节律等问题<ref>{{cite journal | last2 = Burns| first2 = Thomas P.| last= Higashi| first=Masahiko| last3= Patten| first2=Bernard C.| date = 1993 | title = Network trophic dynamics: the tempo of energy movement and availability in ecosystems| journal = Ecological Modelling| volume = 66| pages =43-64}}</ref>。<br />
<br />
将流网络建模成马尔科夫链不仅仅可以讨论流量、时间等问题,还可以讨论如电导经过某点中转的平均首达时间等问题。<ref>{{cite journal | last = Hilfer| first = R.| last1= Blumen| first=A.| date = 1988| title = Probabilistic interpretation of the Einstein relation| journal = Physical Review A| volume = 37| pages =578-581}}</ref><br />
<br />
<br />
<references><br />
<br />
==相关词条==<br />
<br />
[[流网络]]<br />
<br />
[[category:流网络]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%9F%83%E6%96%87_%C2%B7_%E6%B1%A4%E6%99%AE%E6%A3%AE_Evan_Thompson&diff=15169
埃文 · 汤普森 Evan Thompson
2020-10-14T14:00:15Z
<p>Thingamabob:创建页面,内容为“https://evanthompson.me/ File:埃文.jpg ==基本信息== 埃文·汤普森,温哥华英属哥伦比亚大学哲学教授,亚洲研究系和心理学系(认…”</p>
<hr />
<div>https://evanthompson.me/<br />
[[File:埃文.jpg]]<br />
==基本信息==<br />
埃文·汤普森,温哥华英属哥伦比亚大学哲学教授,亚洲研究系和心理学系(认知科学组)副成员。他是加拿大皇家学会的会员。他研究的是心灵、自我和人类经验的本质。他的作品结合了认知科学、精神哲学、现象学和跨文化哲学,尤其是亚洲哲学传统。埃文是加拿大皇家学会的当选会员。埃文1983年在阿默斯特学院获得亚洲研究的学士学位,1990年在多伦多大学获得哲学博士学位。2005年至2013年,他在多伦多大学担任哲学教授,2002年至2005年在约克大学担任加拿大认知科学和具身心灵研究主席。2014年,他被加州大学伯克利分校(University of California, Berkeley)佛教研究中心邀请为客座教授。他还应邀访问了耶拿市弗里德里希-席勒大学哲学系、巴黎理工学院、哥本哈根大学主观性研究中心和博尔德市科罗拉多大学哲学系。2012年,他试着与基督教Coseru杰伊·加菲尔德,国家人文基金会夏季研究所调查意识:佛教和当代哲学的观点,他将再次联合,Coseru和加菲尔德,2018年NEH夏季研究所的东方和西方哲学的自我认识。埃文目前担任精神和生命研究所指导委员会的联合主席,并是英属哥伦比亚纳尔逊卡莱因中心对话和教育工作小组的成员。Evan的妻子Rebecca Todd是认知神经学家和心理学家。托德是英属哥伦比亚大学(University of British Columbia)心理学系的助理教授,并领导着动机认知实验室(Motivated Cognition Lab)。<br />
==研究领域==<br />
近年来,对色彩视觉的研究一直是认知科学的主要成功案例之一,因为该领域的每一门学科——神经科学、心理学、语言学、计算机科学和人工智能,以及哲学——都对我们对色彩的理解做出了重大贡献。埃文·汤普森的书是对这一跨学科项目的重大贡献。色彩视觉提供了一个通俗易懂的回顾,目前的科学和哲学讨论的色彩视觉。汤普森在对颜色的主观和客观立场之间进行了一场辩论,并提出了一个相关的解释。<br />
==联系方式==<br />
*电话:604 8270027<br />
*传真:604 822 8782<br />
<br />
==主要著作==<br />
<br />
*《清醒、做梦、存在:神经科学、冥想与哲学中的自我与意识》(哥伦比亚大学出版社,2015);<br />
*《生命中的心灵:生物学、现象学与心灵科学》(哈佛大学出版社,2007);《色彩视觉:认知科学与知觉哲学研究》(劳特利奇出版社,1995)<br />
*弗朗西斯科·j·瓦雷拉(Francisco J. Varela)和埃莉诺·罗奇(Eleanor Rosch)合著了《具身心灵:认知科学与人类体验》(the Mind: Cognitive Science and Human Experience,麻省理工学院出版社,1991年,2016年修订版)<br />
==相关链接==<br />
*脸书链接:https://www.facebook.com/evan.timothy.thompson?ref=ts&fref=ts<br />
*推特链接:https://twitter.com/evantthompson<br />
[[Category:自创生理论]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%9C%A3%E5%A1%94%E8%8F%B2%E7%A0%94%E7%A9%B6%E6%89%80%E6%8E%A8%E8%8D%90%E4%B9%A6%E7%B1%8D%E5%88%97%E8%A1%A8&diff=15167
圣塔菲研究所推荐书籍列表
2020-10-14T13:54:44Z
<p>Thingamabob:创建页面,内容为“ 复杂性科学的43个愿景 43 Visions for Complexity(未建立词条) 要应对21世纪人类社会的复杂性,需要更深入的定量性、预测…”</p>
<hr />
<div><br />
[[复杂性科学的43个愿景 43 Visions for Complexity]](未建立词条)<br />
<br />
要应对21世纪人类社会的复杂性,需要更深入的定量性、预测性的理解和分析。在这本宝贵的书中,43位国际知名的科学家和思想家分享了他们对复杂性科学下一个十年的发展愿景。主题包括复杂性科学和大数据科学如何帮助社会应对未来的巨大挑战,以及新成立的[[维也纳复杂性科学中心 Complexity Science Hub Vienna]]如何在这条道路上发挥推动作用。<br />
<br />
标签:Complex Systems, Data Science<br />
<br />
作者:Thurner, Stefan<br />
<br />
<br />
<br />
[[可持续发展下的复杂性方法论 A Complexity Approach to Sustainability]](未建立词条)<br />
<br />
商业可持续性和可持续发展在当代社会经济研究中具有重要意义。 尽管如此,系统科学和复杂性科学最近在解决这些问题方面的贡献的影响尚未渗透到有效的实践中。 在这本书中,作者认为在可持续性研究,特别是在全球气候变化的背景下,迫切需要应用体现复杂性管理原则的分析工具。 所提出的办法是基于通过协作将整个系统集合在一起的概念,这样可以创造一个更大的系统,这个系统能够解决我们的社会-经济-环境系统所面临的问题。<br />
<br />
标签:Sustainability, Biology<br />
<br />
作者:Espinosa, Angela and Walker, Jon<br />
<br />
[[合作物种:人类的互惠性及演化 A Cooperative Species: Human Reciprocity and Its Evolution]](未建立词条)<br />
<br />
这本书有对应的中文版本,本书的作者作为人类行为学在实验和进化科学方向的先驱者,在这本书阐述了基因和文化的变革如何造就一个族群—在这个族群里,大部分人为了维护伦理准则和帮助他人,哪怕是陌生人,而愿意牺牲自己的利益。从人类的几千年的发展历史来看,小组成员之间的互相合作,是生存下来的必要条件。这本书使用了大量实验、考古、基因学和人种学的数据来建立共同进化的模型。<br />
<br />
标签:Evolution, Game Theory, Social Systems, Social Science, Agent-Based Modeling, Dynamical Systems<br />
<br />
作者:S. Bowles and H. A. Gintis<br />
<br />
[[粗看整体性 A Crude Look at the Whole:The Science of Complex Systems in Business, Life, and Society]](未建立词条)<br />
<br />
在本书中,社会科学家恶化经济学家约翰·米勒给我们展示了为什么我们需要从整体视角来看待世界。首先,无论我们谈论的是股票市场、计算机网络还是生物有机体,只有当我们意识到这些部分是大系统的部分时,单个的部分才有意义。 也许更重要的是,这些整体可以表现出与部分截然不同的行为。米勒是计算领域研究[[复杂适应系统 Complex Adaptive Systems]]的杰出专家,揭示了不同结构组织之间整体的连接模式:这看起来很粗糙,但是蜂巢的温度控制系统可以帮助预测市场波动,哺乳动物的心跳可以帮助我们了解一个城市的“心跳”,并且相应地调整城市规划。从持续的种族隔离到突如其来的股票市场灾难,一旦我们开始在系统之间建立联系,我们就可以解决那些看起来很棘手的问题。正式由于这种颠覆式的观点,我们最终可以超越还原论的局限性,发现新的关键思想。这本书是一个非常强有力的探索对于我们社会所面临的挑战,且非常具有科学性和可读性。正如这本书所揭示的,粗看整体可能才是真正看到的唯一途径。<br />
<br />
标签:Complex Systems<br />
<br />
作者:Miller, John<br />
<br />
<br />
[[网络理论初级课程 A First Course in Network Theory]](未建立词条)<br />
<br />
网络理论的研究是一个高度跨学科的领域,已经成为从物理学到数学,从生物到社会科学各个学科的主要兴趣话题。这本书通过平衡不同学科背景学生的需求,从不同角度研究复杂网络。它引用了网络理论中最常用的概念,举例说明了它们在解决实际问题中的应用,并明确指出了如何分析它们的结果。在本书的第一部分,学生和研究人员将发现处理复杂网络所必需的定量和分析工具,包括网络和图论、线性和矩阵代数的最基本概念,以及研究网络最常用的物理概念。 他们还将获得一些关键技能的指导,如如何证明分析结果和如何操作经验网络数据。<br />
<br />
<br />
<br />
标签:Networks<br />
<br />
作者:Ernesto Estrada & Philip Knight<br />
<br />
[[首达过程指南 A Guide to First-Passage Processes]](未建立词条)<br />
<br />
首达过程在随机过程中是一个普遍常用的性质,比如扩散限制生长,神经元放电,和股票期权的触发。这本书对于手打过程提供了一个统一的描述,突出了它与静电学的相互联系,和由此产生的重大结果。作者刚开始用一个非常现代化的表示介绍了基础理论,包括一个随机游走的首达概率和occupation,以及与电阻网络中静电和电流的关系。介绍了各种应用,包括神经元动力学,自组织临界性,扩散有限聚集,自旋系统的动力学,扩散控制反应动力学。 讨论的例子包括神经元动力学,自组织临界性,自旋系统的动力学和随机共振。(需确认)<br />
<br />
<br />
标签:Physics, Chemistry, Mathematics<br />
<br />
作者:Rednor, S.<br />
<br />
<br />
[[时序网络指南 A Guide to Temporal Networks]](未建立词条)<br />
<br />
本书介绍了新兴的时序网络最新的理论和建模进展,并且提供了处理一多交叉的新兴学科所需要的不同领域知识之间的联系。在介绍了网络和随机动力学的关键概念之后,作者和读者可以形成网络动力学是数学和计算工具的统一的共识。这本书不管是对学生还是教授都是一本很好的入门指南,尤其是对于应用数学、物理和计算机等基础学科以及包括社会科学、神经科学和生物等应用领域而言,这个主题都是一个热门的研究。<br />
<br />
<br />
标签:Networks, Dynamical Systems<br />
<br />
作者:Masuda, Naoki, and Lambiotte, Renaud<br />
<br />
<br />
[[一种新科学 A New Kind of Science]](厚朴已建立词条)<br />
<br />
本书是[[史蒂芬·沃尔夫勒姆 Stephen Wolfram]]于2002年出版的一本畅销书,颇具争议。 它的主要内容是对像元胞自动机这样的计算系统经验化和系统化的研究。沃尔夫勒姆称这些系统为简单的程序,并认为适合研究简单程序的科学哲学和方法与其他科学领域有关。<br />
<br />
标签:Computation, Cellular Automata, Complex Systems<br />
<br />
作者:[[史蒂芬·沃尔夫勒姆 Stephen Wolfram]]<br />
<br />
<br />
<br />
<br />
[[自然与人工系统中的适应 Adaptation in Natural and Artificial Systems]](未建立词条)<br />
<br />
《自然与人工系统中的适应:理论分析及其在生物控制和人工智能中的应用》是遗传算法开山之作,以适应性为主题,贯穿生物、经济、人工只能等多种科学,描述有关自然和人工系统中的适应问题背后隐藏的规律性及其理论,建立统一的适应性系统的理论框架,展示使计算机程序自发进化的遗传算法,以严格的数学定理揭示了算法背后的理论本质。这本书的翻译版本由北京师范大学教授张江老师翻译。<br />
<br />
标签:Complex Systems, Genetics, Artificial Life, Artificial Intelligence, Neuroscience, Game Theory, Genetic Algorithms<br />
<br />
作者:[[约翰·霍兰德 John Holland]]<br />
<br />
[[自适应协作系统 Adaptive Cooperative Systems]](未建立词条)<br />
<br />
这是关于自组织过程的一次全面、最新的探索。这使得我们对自组织协作系统的理解突飞猛进,对生命的本质和人类意识有了新的认识,同时为一系列广泛的技术问题提供了解决方案。本书的目的是为了帮助在信号处理、神经科学和机器人学等领域的研究人员跟上自适应协作系统的最新进展。自适应协作系统清晰的阐述了统计物理最新自适应协作模型和方法背后的统计物理规律,描述了随机概率方法并说明了如何用该方法创造可以用于解决不同研究领域问题的算法,描述了在生物系统中自组织协作行为最新的重要发现,提供了从地球科学、天体物理学、图像处理、机器人学、人工智能和其他学科的提炼的例子,合作计算理论作为一个严格的理论在感知推理问题中被广泛应用。<br />
<br />
<br />
<br />
标签:Complex Systems, Emergence<br />
<br />
作者:M. Beckerman<br />
<br />
[[进化种群中的适应性个体:模型与算法 Adaptive Individuals in Evolving Populations: Models and Algorithms]](未建立词条)<br />
<br />
这本书来自于由圣塔菲研究所资助的自适应计算项目所举办的一个眼讨论,它聚集了20多余名科学家,来自生物学、心理学和计算机科学等多个交叉学科,他们都研究种群进化和个体在这些种群中的适应性之间的相互作用。本书包括从一系列跨学科的观点探索相互作用的适应系统的论文。有一大半的文章都是关于这个主题的经典的、有开创性的文献,比如从Lamarck和Waddington这样的生物学家到Piaget和Skinner这样的心理学家。另一半的文章是参与会议的科学家的最新研究作品。这些新论文特别强调了数学和计算工作所起的作用,他们它们既是自然现象的模型,也是有用的算法。<br />
<br />
<br />
标签:Evolution, Modeling<br />
<br />
作者:M. Mitchell<br />
<br />
[[应用自组织系统最新研究 Advances in Applied Self-organizing Systems]](未建立词条)<br />
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我们如何设计一个自适应系统?是否有可能验证和控制非确定性动力学?在涌现模式下带来的鲁棒性、适应性和规模性和对结果核实和验证的传统需求之间,什么是正确的平衡?在过去的十几年里,我们看到许多进步,从“涌现功能性”到“涌现设计”的原创性想法,到具有规范数学形式的“指导性自组织”,然而,最大的挑战仍然存在,就是如何吸引最好的科学家和工程专家来关注这个难以琢磨的问题。这本书成功的展示了工程自组织系统的实践状态,并检验了在应用环境中平衡设计和自组织的方法。正如这本书的第二版所强调的那样,找到这种平衡有助于应对各种各样的实际挑战,如在心血管内微型机器人的导航,自我监控的航空航天器、适用于自主侦察和监视的模块化集群机器人、自我管理的网格和多处理器调度、数据可视化和自调整的数字化模拟电路、计算机网络中的入侵检测、水力物理场的重建、交通管理、免疫计算以及自然启发计算。本书提出和讨论的都是受生物启发的算法,通过阅读这本书,读者将会对元胞自动机、遗传算法、人工免疫系统、蛇形运动、蚂蚁觅食、鸟群聚集、神经电路等等,展示了自组织的实际相关性和适用性,是不同领域的学生和研究员了解最新进展不可或缺的工具。<br />
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标签:Emergence, Artificial Life, Artificial Intelligence, Computation, Epidemiology, Public Health, Self-Organization, Ecology<br />
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作者:Mikhail Prokopenko<br />
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[[基于主体和个体的建模:一个实用的介绍 Agent-Based and Individual-Based Modeling: A Practical Introduction]](未建立词条)<br />
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主体建模是一种新的技术,对于理解生物、社会和其他复杂系统的动力学是如何从组成这些系统的主体的特征和行为中产生的。这本有新意的教科书,培养学生和科学家设计、应用、以及分析主体模型的能力。它从建模的基础知识入手,介绍了Netlogo,这是一个易于使用、免费且强大的软件平台。接下来的九章,每一章都介绍了一个重要的建模概念,并且告诉我们如何用Netlogo去实现它。接着这本书又介绍了找到不同模型水平复杂度的策略,并且发展了的用于从其他模型中分析和学习主体行为的理论。<br />
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标签:Agent-Based Modeling, Modeling<br />
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作者:S. F. Railsback & V. Grimm<br />
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[[基于主体的建模:圣塔菲研究所人工股票市场模型的再探索 Agent-based Modeling: The Santa Fe Institute Artificial Stock Market Model Revisited]](未建立词条)<br />
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这本书调和了技术交易的存在和市场有效假说之间的矛盾,通过分析一个著名的主体模型,圣塔菲研究所人工股票市场。它发现当选择力量弱的时候,金融进化不能保证只有最适合的交易规则才能生存。它的主要贡献在于应用了在主体社区中被广泛地忽视的群体遗传学的标准结果。<br />
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标签:Agent-Based Modeling, Economics, Emergence<br />
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作者:E. Norman<br />
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[[主体建模 Agent-based Models]](未建立词条)<br />
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主体建模是一种技术,现在被越来越广泛地应用在社会科学中。它涉及到建立包含“主体”的计算模型,每个主体都代表着社会世界的一个扮演者,“环境”就是主体的存在的地方。主体能够相互交互,并且被设定为积极主动、自主、且能感知他们所在的虚拟世界。主体建模的技术起源于人工智能,和计算科学,但目前正在全世界的研究中心作为一个独立的研究方向。在本书中,作者回顾了一系列主题建模的例子,描述了如何设计并构建你自己的模型,并且考虑了诸如验证、确认、规划建模项目等实际问题,以及如何基于主题建模的结果构建一个学术报告。它包含了一个术语表、一个带注释的资源列表、在构造主体模型时的编程环境建议和一个有实操性、手把手地开发主体模型的示例。<br />
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标签:Agent-Based Modeling,<br />
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作者:[[奈杰尔·吉尔伯特 Nigel Gilbert]]<br />
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[[代数自动机理论 Algebraic Automata Theory]](未建立词条)<br />
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这是对机器代数理论的一种独立的、最新的著作。作者研究了机器概念在生物、生物化学和计算机科学中的各种应用,并且对机器可以通过更简单的机器被分解和模拟的方式给出了严格的实验方法,这种实验的基本思想是来自于近世代数。许多新结果背后的动机是通过应用程序提供的,所以这个程序对应的账号,对于那些学习应用代数和计算科学理论的本科生或者研究生低年级学生,以及在这个领域的研究者应该是有价值且可获得的。<br />
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标签:Cellular Automata, Mathematics<br />
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作者:W.M.L. Holcombe<br />
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[[主体建模方法介绍 An Introduction to Agent-Based Modeling]](未建立词条)<br />
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快速计算的广泛应用使我们能处理更复杂的问题,并建立和分析更复杂的模型。本书是关于主体建模核心概念方法和应用的介绍,全面且容易上手,包括大量、详细的Netlogo教程。这本书是关于研究这个新领域知识的主要方法论的介绍。主体建模提供了一个做科研的新方式:通过计算机进行实验。主体建模适合嵌入在自然、社会、和工程环境中的复杂系统,跨越从工程到生态学各个领域。本书首先描述了主体建模的性质和基本原理,然后提出了设计和建立主体模型的方法论,接着讨论了如何利用主体模型来回答复杂问题,最后给出了参考文献和相关阅读清单。还有一个附带的网站,上面有所有的模型和代码。<br />
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标签:Agent-Based Modeling, Modeling, Complex Systems<br />
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作者:Uri Wilensky and William Rand<br />
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[[复杂系统介绍 An Introduction to Complex Systems]](未建立词条)<br />
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这本书探索的是复杂系统理论的跨学科领域。读完本书,读者将能够理解复杂系统里面使用的术语以及他们之间是如何相互关联的,用实际案例理解复杂系统的模式;在各个领域映射复杂性理论;能够阅读这个领域更多的前沿文献。这本书是由基本的系统概念开始的,接着介绍简单规则如何导致复杂行为,然后作者介绍了非线性系统、模式形成、系统中的网络和信息流。后面的章节包含了复杂系统中的热力学、网络中出现的动力学模式,以及博弈论如何作为决策的框架。文本中穿插着哲学和定量的论点,每一章都以问题和提示结尾,帮助读者建立更多的联系。<br />
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标签:Complex Systems<br />
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作者:Joe Tranquillo<br />
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[[遗传算法导论 An Introduction to Genetic Algorithms]](未建立词条)<br />
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遗传算法在科学和工程作为解决实际问题的自适应算法和自然进化系统的计算模型,本书通过简单、易懂的介绍,描述了一些在这个领域最感兴趣的研究,同时也能让读者可以实现和实验自己的遗传算法。它深入关注了一小部分重要而有趣的主题,特别是机器学习、科学建模和人工生命;同时它回顾大量研究,包括作者本人和她的同事们的研究。本书对学科的学生和研究人员来说都是可以理解的。 它包括许多思想和程序练习,可以建立和加强读者对文本的理解。 第一章介绍了遗传算法及其术语,并详细描述了两个具有挑战性的应用。 第二和第三章着眼于遗传算法在机器学习(计算机程序、数据分析和预测、神经网络)和科学模型(学习、进化和文化之间的相互作用; 性别选择; 生态系统; 进化活动)中的应用。 第四章对遗传算法理论的几种方法进行了深入的讨论。 第五章讨论了实施问题,最后一章提出了一些目前尚未解决的问题,并展望了进化计算的未来。<br />
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标签:Genetic Algorithms<br />
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作者:M. Mitchell<br />
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[[信息论导论 An Introduction to Information Theory]](未建立词条)<br />
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在电话、收音机和电视这些熟悉表面的背后,隐藏着一个复杂而有趣的知识体系,即信息论。 这个理论已经渗透到各种通信的快速发展中,从彩色电视到木星附近照片的清晰传输。 预计未来还会有更多的颠覆性进展。 为了给这个新兴的领域一个科学有力的介绍,作者已经修订了他从1996年出版就广受好评的研究信息论,作为即将面世的第二版。从这个领域的起源开始,作者沿用了克劳德 · 香农的伟大公式,描述了编码和二进制数字、熵、语言含义,有效编码,以及噪声信道等主题的方方面面。 然后,他超越了这些主题的严格定义,探索了信息理论与物理学、控制论、心理学和艺术相关的方式。 为了有利于认真学习的学生,作者在适当的地方引入数学公式,同时为了帮助那些不太精通数学的人,也提供了术语表和数学符号的附录。<br />
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标签:Entropy, Information Theory, Artificial Life, Artificial Intelligence<br />
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作者:J. R. Pierce<br />
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[[柯尔莫哥洛夫复杂度及其应用简介 An Introduction to Kolmogorov Complexity and Its Applications]](未建立词条)<br />
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本书是由该领域的2名专家一起撰写的,对于各个领域的高年级的本科生、研究生和研究员而言都是理想的学习材料。这本书是一个完整的整体:涵盖了来自数学、概率论、统计学、信息理论和计算机科学的基本要求。 包括该领域的历史,理论,最新发展,广泛的应用,众多(新的)问题集,评论,来源参考,和提示的解决方案的问题。 这是对柯氏复杂性的中心思想及其应用的综合性读物之一。<br />
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标签:Information Theory<br />
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作者:M. Li & P. Vitanyi<br />
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[[社会科学模型概述 An Introduction to Models in the Social Sciences]](未建立词条)<br />
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什么是模型?你知道如何建模吗?社会科学中的常见模型有哪些?一个模型如何应用在一个新的情境下?什么是一个好的模型?针对这些问题的答案以及一些其他的相关问题,这个对于社会科学交叉学科中模型构建的介绍,主要是针对学生在创造性模型构建以及发现过程所形成的有趣的问题。这本书介绍了个人选择、交换、适应和扩散的模型。 自始至终,鼓励学生用分析性思维思考问题。<br />
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标签:Modeling, Social Systems, Social Science<br />
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作者:C. A. Lave & J. G. March<br />
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[[概率论及其应用 An Introduction to Probability Theory and Its Applications]](未建立词条)<br />
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本书为第3版,涉及面极广,不仅讨论了概率论在离散空间中的诸多课题,也涉及了概率论在物理学、化学、生物学(特别是遗传学)、博弈论及经济学等方面的应用,主要内容有:样本空间及其上的概率计算,独立随机变量之和的随机起伏,事件的组合及条件概率,离散随机变量及其数字特征,大数定律,离散的马尔可夫过程及其各种重要特征,更新理论等,除正文外,还附有六七百道习题和大量的附录。<br />
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标签:Mathematics, Statistics<br />
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作者:W. Feller<br />
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[[转移熵概述:复杂系统中的信息流 An Introduction to Transfer Entropy: Information Flow in Complex Systems]](未建立词条)<br />
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本书考虑了复杂系统中一个相对新的度量,转移熵,来源于对时间序列的大量观测。在一个章节的定性介绍之后,另一个章节解释这个内容理解所备的统计学思想;接着作者深入地介绍了信息论和转移熵。该方法的一个关键性质就是作者对于信息流和复杂度关系的研究工作,后面的章节则介绍了在规范系统(如神经科学和经融学)方面的信息转移和应用。这本书适用于在计算机科学、神经科学、物理学和工程领域的高年级本科生、研究生或者研究者。<br />
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标签:Information Theory, Thermodynamics<br />
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作者:T. Bossomaier, L. Barnett, M. Harré, J.T. Lizier<br />
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[[自动机理论和代数的应用 Applications of Automata Theory and Algebra]](未建立词条)<br />
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这本书最初是由伯克利的数学家John Rhodes在1969年所写。它被称为是代数工程的基础工作,这是一个新兴的领域,它是通过利用有限状态机模型及其复杂性创造统一性的框架,从而将将有限群理论、半群理论、自动机和顺序机理论、有限相空间物理学、代谢和进化生物学、认识论、精神分析的数学理论、哲学和博弈论等多个领域联系起来。因此作者介绍了一个完全原始的代数方法来理解复杂性和有限系统。这本书未出稿的手稿,通常被称为“野书”,成为一本未发表的经典,并要求持续更新手稿的信息,被很多来自数学,复杂系统,人工智能,和系统生物学的研究员阅读。但是这本书到现在也还没有出版。<br />
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标签:Game Theory, Cellular Automata, Mathematics<br />
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作者:John Rhodes<br />
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[[人工生命概述 Artificial Life: An Overview]](未建立词条)<br />
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人工生命是一个旨在提高协同在生物现象研究中作用的领域,对于揭开生命的秘密和提出一系列关于科学技术以及哲学和伦理等令人不安的问题方面有巨大的潜力。这本书汇集了一系列的综述文章,这些文章都是来源于开创性期刊《人工生命》的前3期,以及一个关于[[克里斯托弗·朗顿 Christopher Langton]]的介绍,他是《人工生命》的主编,该学科创始人,圣塔菲研究所生命计划项目主任。<br />
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标签:Artificial Life, Artificial Intelligence<br />
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作者:[[克里斯托弗·朗顿 Christopher Langton]]<br />
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[[随机游走的特点及应用 Aspects and Applications of the Random Walk]](未建立词条)<br />
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尽管随机游走的重要性在各个方面的应用都显然易见,但是很少有书专门介绍这个概念。因此,对这个主题及时的介绍,将会受到一些没有接触过学生和更多的高级研究员的欢迎。作者集中在这个主题几个简单的方面,主要集中在马尔科夫模型,或者与马尔科夫公式密切相关的模型。具有马尔科夫和费马尔科夫两个方面的随机游走就是这类模型的例子。随机游走模型的渐近性质一直都是研究的重点,因为他们普遍的形式使得数学形式得到了广泛的应用。<br />
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标签:Physics, Modeling, Mathematics<br />
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作者:Weiss, G. H.<br />
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[[元胞自动机和复杂性:论文集 Cellular Automata and Complexity: Collected Papers]](厚朴已建立词条)<br />
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数学方程是模拟自然最好的方式吗?至少很长一段时间以来,人们都是这样认为的。但是在20世纪80年代早期,[[史蒂芬·沃尔夫勒姆 Stephen Wolfram]]提出了一种特别的方式,他认为人们应该基于直接而简单的计算机程序来建模。他对一类被称为元胞自动机的模型进行深入的研究,发现了一个事实:基于简单的规则,可以演化出高度复杂的行为,并且可以模拟出自然界中的很多现象。基于这样一个事实,他开始了一个新的研究项目,成为复杂性科学,他的研究结果被应用在很多方面,从所谓的分类到人工生命,再到密码学和流体力学的新思想。这本书收集了Wolfram关于元胞自动机和复杂性研究的原始论文,有一些是科学界广为人知的论文,有一些也从来没有发表过。元胞自动机已经成为了一个新的研究领域,在物理学、经济学和计算机科学许多影响具有非常重要的影响。<br />
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标签:Cellular Automata, Complex Systems, Systems Theory<br />
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作者:S. Wolfram<br />
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[[元胞自动机:一种新的建模环境 Cellular Automata Machines: A New Environment for Modeling]](厚朴已建立词条)<br />
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最近,元胞自动机凭借着大小、速度、和灵活性,且对于一般的实验,价格优惠,已经被科学界广泛应用。这些机器提供了一个实验室,可以对来自于文本中的一些想法,在各种不同的系统中进行测试和应用。对于建模和仿真感兴趣,以及从事数学建模的科学家来说,这篇关于元胞自动机的介绍非常的适用且不过时。元胞自动机对于计算机科学家来说,就像“场”对于物理学家来说一样重要。它们为物理学、组合数学和计算机科学家的许多研究提供了自然的模型,尤其是针对那些研究涉及到那些在空间上扩展,在时间上随着规则局部演化的系统。元胞自动机机器是一台专门针对元胞自动机仿真进行优化的机器。从同样的成本和任务,它的专用结构使其可以运行比通用计算机的速度快成千上万倍。 在实际应用中,这允许进行密集的交互实验,并开辟了分布式动力学研究的新领域,包括涉及并行计算和图像处理的实际应用。<br />
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标签:Cellular Automata<br />
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作者:T. Toffoli & N. Margolus<br />
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[[元胞自动机:一个离散的宇宙 Cellular Automata: A Discrete Universe]](未建立词条)<br />
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元胞自动机是一类空间和时间上都离散的数学系统,具有局部相互作用和协同演化的特性。由数学家[[约翰·冯·诺依曼 John von Neumann]]在20世纪50年代发明了这个模型,作为生物自复制的简单模型。他们是复杂系统和过程的原型模型,由大量的、同质的、局部的相互作用的成分组成。多年来,元胞自动机一直是人们关注的焦点,因为他们能够一系列相对简单的规则中演化出非常复杂的行为模式,而且,它们似乎可以捕捉到真实系统中观察到自组织和协作行为的基本特征。这本书总结了元胞自动机的基本性质,并且,深入地探索了许多和元胞自动机相关的其他领域,包括人工生命、混沌、涌现、分形、非线性动力系统和自组织。这本书适合于想要学习了解秩序、混沌和复杂性涌现学生、老师或者研究者。它涵盖了一个广泛的参考书目,以及在网络上可以找到的关于元胞自动机的资源清单。<br />
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标签:Artificial Life, Artificial Intelligence, Dynamical Systems, Cellular Automata, Neural Networks<br />
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作者:A. Ilachinski<br />
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[[元胞自动机:理论和实验 Cellular automata: Theory and experiment]](未建立词条)<br />
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元胞自动机,空间和时间上的离散动力系统,正在屋里和自然科学中产生着有趣的应用。这本书涵盖了当代研究元胞自动机的很多资源,包括综述、研究报告、近期的文献指南和可用软件等。每个章节瀚海数学分析、关于元胞自动机的空间结构,特定性质的学习规则,元胞自动机在生物、物理、化学、计算机科学中的应用,以及在神经网络、布尔网络和耦合晶格网络(coupled map lattices)上的概述。<br />
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标签:Cellular Automata, Computation<br />
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作者:H. Gutowitz<br />
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[[自复制自动机理论 Theory of Self-reproducing Automata]](已建立词条)<br />
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自复制自动机理论整理自冯·诺依曼的手稿《自复制自动机理论》,由人工智能先驱 Arthur Burks 整理成书。集智俱乐部资深粉丝“东方和尚”将全书第一部分翻译成中文,张江做了详细点评。我们将其整理成“冯·诺依曼自动机器理论”系列文章,以飨读者。这五篇文章不仅仅预测了复杂性科学未来100年的发展方向(事实上很多领域已经验证了冯纽曼的预言),而且还指出了生命逻辑最核心的奥秘:热力学、信息论与自指之间的深刻联系。<br />
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标签:Control Theory, Computation, Cellular Automata, Artificial Life, Self-reference<br />
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作者:[[约翰·冯·诺依曼 John von Neumann]]<br />
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[[混沌与分形 Chaos and Fractals]](未建立词条)<br />
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这本书的十四个章节涵盖了混沌和分形的中心思想和概念,以及许多相关的主题如:分形与自相似、分形的维数与测度、分形与图像数据压缩编码、随机性与确定性、分形的递归结构、细胞元自动机与吸引子、分形构造中的随机性、确定性混沌:灵敏度、混合与周期点、有序与混沌、奇异吸引子、典型的分形集如Julia集、Mandelbrot集等,重点介绍了分形与混沌的物理意义、两者之间的关系、与数学的其它方面以及自然现象的联系,展示出分形与混沌的在视觉、图像方面的优美结构和图案。<br />
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标签:Dynamical Systems, Mathematics, Fractals, Cellular Automata, Computer Science<br />
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作者:H. Peitgen, H. Jürgens & D. Saupe<br />
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[[混沌与分形: 基本介绍 Chaos and Fractals:An Elementary Introduction]](未建立词条)<br />
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这本书为读者提供了对混沌和分形的基本介绍,适合没有学习微积分或物理学但具有初等代数背景的学生。此书通过简单迭代函数介绍了混沌的重要现象——非周期性、对初始条件的敏感依赖性、分岔现象。 分形被解释为自相似几何物体,并用自相似和box-counting分型维数进行分析。此书不仅讨论到了幂律,接下来的章节涉及到 Julia 集和 Mandelbrot 集。在书的最后一部分阐释了二维动力系统,奇异吸引子,元胞自动机,和混沌微分方程等概念。<br />
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标签:Fractals, Mathematics<br />
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作者:D. P. Feldman<br />
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[[混沌与时间序列分析 Chaos and Time-series Analysis]](未建立词条)<br />
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此书介绍混沌的发展和非线性动力学的有关主题内容,包括检测和实验数据中的混沌量化,分形和复杂系统。涉及非线性动力学中绝大多数重要的基本概念,重点阐述了物理概念和效用结果,而不是在数学上进行证明和推导。虽然许多关于混沌的书籍是定性的,而其他许多书籍则是高度数学化的,但这本书以尽可能简单的形式给出了基本方程式填补了这两者中间地带。<br />
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标签:Physics, Chaos, Dynamical Systems, Fractals<br />
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作者:J. C. Sprott<br />
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[[混沌: 创造新的科学 Chaos: Making a new science]](未建立词条)<br />
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这不是一本纯粹有关技术的书籍。相反的,它关注的重点不仅仅是混沌本身,还有那些研究混沌的科学家。在格莱克的书中,读者会遇到许多非凡而又古灵精怪的人。例如,[[米切尔·费根鲍姆 Mitchell J. Feigenbaum]],他用一个26小时的时钟构建和调整自己的生活,并且观察他醒着的时间与他在[[洛斯阿拉莫斯国家实验室]]的同事的时间是否相同。讨论到混沌本身,格莱克在阐释研究人员用于解决混沌问题的思维过程和调查技术方面描绘得很不错。本书并没有尝试去解释Julia集合、洛伦兹吸引子和庞大复杂的Mandelbort集合,而是依靠草图、照片和格莱克精彩的描述性散文来构成了整本书的内容。<br />
所谓“混沌”,是指看来遵从确定规律的事物也会显现超乎想象的繁复多样,只要有些微的条件差异,就会导致令人瞠目结舌的不同结果。混沌现象在人们的生活中无处不在!上升的香烟柱破碎成缭乱的旋;旗帜在风中前后飘拂;龙头滴水从稳定样式变成随便机样式,混沌现象出现在大气和海洋的湍流中,出现在飞机的飞翔中,出现在高速公路上阻塞的汽车群体中,出现在野生动物种群数的涨落、心脏和大脑的振动以及地下管道的油流中……<br />
混沌理论是继相对论和量子力学问世以来,20世纪物理学的第三次革命,其覆盖面广及自然科学与社会科学的几乎各个领域。它不仅改变了天文学家看待太阳系的方式,而且开始改变企业家做出保险决策的方式,改变政治家谈论紧张局势导致武装冲突的方式等等。混沌理论正促成整个现代知识体系成为新科学。<br />
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标签:Chaos, Dynamical Systems, Fractals, Nonlinear Dynamics<br />
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作者:J. Gleick<br />
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[[城市与复杂性: 运用元胞自动机、主体建模和分形理解城市]](未建立词条)<br />
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随着城市规划从集中的、自上而下的模式转向分散的、自下而上的模式,我们对城市系统概念的认知正在发生变化。 在书中,迈克尔 · 巴蒂在复杂性理论的背景下提供了城市动态的全面观点,展示了复杂性理论如何包含无数的过程和元素,并将其组合成有机整体的模型。 他认为,自下而上的过程——其结果总是不确定的——可以与与分形模式和混沌动力学相关的新几何形式相结合,提供适用于城市等高度复杂系统的理论。 Batty 从基于元胞自动机(CA)的模型开始,通过自动机的局部作用模拟城市动态。 然后,他介绍了[[主体建模 Agent-based Models]](ABM) ,其中代理主体是可移动的,并在位置之间移动。 这些模型涉及到许多尺度,从街道的规模到城市地区规模的模式和结构。 最后,Batty 开发了所有这些模型在特定城市情况下的应用,在空间发展的背景下讨论了临界性、阈值、突然性、新颖性和相变等概念。 书中提出的每一个理论和模型都是通过从简化和假设到实际的例子发展起来的。利用大量的视觉、数学和文本材料,《城市与复杂性》将被城市研究人员和对新型计算模型感兴趣的复杂性理论学者阅读。<br />
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标签:Cellular Automata, Scaling, Agent-Based Modeling, Cities<br />
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作者:M. Batty<br />
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[[攀登不可能之山 Climbing Mount Improbable]](未建立词条)<br />
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人类的眼睛是如此的复杂而又精确,人们可能会相信,人现在的形状和功能一定是精心设计的产物。 这样一个错综复杂的物体怎么会偶然间出现呢? 在《纽约时报》称之为“杰作”的文章中,[[理查德·道金斯]]阐述了这一主题,并建立了一个仔细推理和令人瞩目的论点,认为进化适应是地球上生命的机制。“不可能的山”的比喻代表了完美和不可能性的结合,集中体现在看似“设计”的生物复杂性上。 道金斯巧妙地引导读者进行了一次惊险的旅行,穿过山口,爬上山顶,向读者证明,沿着不可能的道路走向完美是需要时间的。 道金斯聪明地描述了一些非凡的适应性变化,例如无花果的大量繁殖,蜘蛛复杂的丝绒世界,以及不会飞的动物身体上翅膀如何进化。通过它所有运行的 DNA 线,生命的分子,管理着自己的命运,在一个无休止的朝圣之旅之间超越时代。<br />
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标签:Evolution, Biology, Origins of Life<br />
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作者:[[理查德·道金斯 Richard Dawkins]] <br />
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[[人工智能社会中的协调: 社会结构及其对自主解决问题智能体的影响 Co-ordination in Artificial Agent Societies: Social Structures and Its Implications for Autonomous Problem-Solving Agents]](未建立词条)<br />
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这本专著提供了人工创造的人类主体模型社会中协调的不同方法的全局概览。从对现有技术的批判性评估出发,作者开发了一种利用结合结构化合作机制构建多智能体应用程序的方法。其中的主体拥有关于其所处环境的专类知识,以便发现和克服特定类型的问题,他们也能够利用其社会知识相互调整其活动,也在特定情况下通过规范性规则采取连贯的集体行为。这一系列行为都能利用博弈论对该模型进行形式化来描述,并通过 agent 体系结构实现。另一方面,对一类通过建立分布式道路交通管理决策支持系统的原型进行了实验评估,并和基于集中式体系结构的替代模型进行了对比。这套方法的闪光点在于,它不仅促进了人工代理社会中一个建立良好的正式协调模型,而且还将其应用于作为智能代理社会组织的一个操作性软件架构,以解决现实世界中的问题。<br />
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标签:Agent-Based Modeling, Artificial Life, Artificial Intelligence, Game Theory, Social Systems<br />
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作者:Sascha Ossowski<br />
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[[基于碰撞的计算 Collision-based Computing]](未建立词条)<br />
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基于碰撞的计算提供了一种独特的概述,包括在非线性介质中移动的自定位模式的计算,光学媒介的计算,大规模并行处理机计算机的数学模型和分子系统中的内容。同时还涉及台球模型及其元胞自动机类似物中的计算、晶格气体中计算装置的运行、[[约翰·康威 John Conway]]的[[生命游戏]]和离散激发介质、粒子机理论、孤子计算、弹道计算逻辑、计算现象学和自复制通用计算机等多种学科的内容。基于碰撞的计算将是研究人员在计算科学,数学物理和工程相关主题的着眼点。也将为研究生课程提供有用的背景阅读,如光计算,自然启发计算(有待确定),人工智能,智能工程系统,复杂和自适应系统,并行计算,应用数学和计算物理学.<br />
标签:Computation<br />
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作者:Andrew Adamatzky1<br />
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[[复杂适应系统: 计算社会模型导论 Complex Adaptive Systems: An Introduction to Computational Models of Social Life ]](未建立词条)<br />
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这本书拥有首个概念明确,覆盖全面,易于理解的复杂适应社会系统的目录,由两个领域的权威背书。无论是对于政党、股票市场还是蚁群的系统的研究,他们都提出了社会科学所面临的一些最有趣的理论和实践挑战。复杂自适应系统有其自身魅力,并能够在技术细节和直观的解释之间平衡。一些关键性的工具和想法,自20世纪90年代中期以来已经出现,用来研究这类系统。它详细介绍了涌现、自组织临界性、自动机、网络、多样性、适应和反馈等概念。 同时演示了如何利用从使用数学到自适应代理的计算模型的方法来探索复杂的自适应系统。此书还包括Scott Page 展示如何结合来自经济学、政治学、生物学、物理学和计算机科学的观点,进一步阐明组织性、适应性、地方分权和鲁棒性等议题。同时还展示了如何卓有成效地超越建模中常见的极端。值得深入探究。<br />
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标签:Complex Systems, Cellular Automata, Networks, Emergence, Adaptation, Modeling<br />
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作者: Scott E. Page<br />
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[[复杂和自适应动力系统: 入门 Complex and Adaptive Dynamical Systems: A Primer]](未建立词条)<br />
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这本入门书向读者介绍了形成我们对复杂和突发行为的现代理解的核心概念,以及相关数学方法的详细内容。 所有的计算都是一步一步来的,并且很容易理解。<br />
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标签:Networks, Dynamical Systems, Chaos, Emergence, Adaptation<br />
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作者:Claudius Gros<br />
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[[复杂工程系统: 科学与技术的结合 Complex Engineered Systems: Science Meets Technology]](未建立词条)<br />
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这本书阐明了塑造和指导我们日常生活的大规模工程系统。它通过汇集最新的研究和实践来检索复杂工程系统的新兴领域。如何理解、设计、构建和控制这些复杂系统将是未来几十年工程师们面临的主要挑战。而这本书的出版是朝着解决这一挑战迈出的一步。<br />
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标签:Technology, Engineering<br />
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作者:Dan Braha Ali A. Minai Yaneer Bar-Yam <br />
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[[复杂的人类动力学: 从思想到社会 Complex Human Dynamics: From Mind to Societies]](未建立词条)<br />
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本书通过社会科学家和心理学家紧密合作编撰而成,将这些领域的典型研究主题重新铸造成非线性、动态和复杂系统的描述。其目的是为具有物理学、应用数学和计算机科学不同背景的科学家提供机会,能够将他们的行业工具应用于一个全新的可能的应用范围之内。 同时,这本书也将成为新一代社会科学家和心理学家的入门之作,他们希望自己能够熟悉新的方法论和”复杂性思维”。<br />
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标签:Nonlinear Dynamics, Social Science, Psychology, Mathematics, Physics<br />
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作者:Andrzej Nowak Katarzyna Winkowska-Nowak David Brée <br />
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[[复杂网络: 结构、鲁棒性和功能 Complex Networks: Structure, Robustness, and Function]](未建立词条)<br />
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这本研究生的教科书阐述了重要的分析技巧和实际成果,一步一步地介绍了复杂网络的结构和功能。通过一系列的例子,从互联网的鲁棒性到有效的免疫人群的方法,从传染病的传播到如何有效地搜索个体,这本教科书都阐述了可以使用的理论方法,以及在复杂网络的研究和研究中获得的实验和分析结果。对复杂网络理论中的许多结果进行了详细的推导,是研究生进入该领域的理想参考。章末复习题有助于学生了解自己对所提供材料的解读程度。<br />
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标签:Scaling, Networks, Fractals<br />
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作者:Reuven Cohen Shlomo Havlin<br />
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[[复杂性与公共政策的艺术 Complexity and the Art of Public Policy]](未建立词条)<br />
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现代分析和计算的进步使复杂性科学的诞生成为可能,与此同时它正在改变我们思考社会系统和社会理论的方式。不幸的是,经济学家的政策模型却没有跟上形势,要么停留在市场原教旨主义,要么停留在政府掌握的叙述中。虽然这些标准的叙述在某些情况下是有用的,但在另一些情况下是有害的,它们将思维从创造性的、创新的政策解决方案引向别处。《复杂性与公共政策的艺术》介绍了一种新的、更加灵活的政策叙述,它将社会设想为一个不可控但可以受到人们影响的复杂演化系统。<br />
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标签:Economics, Complex Systems, Policy<br />
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作者:by David Colander Roland Kupers<br />
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[[创新与社会变革的复杂性视角 Complexity Perspectives in Innovation and Social Change]](未建立词条)<br />
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对于西方世界的许多经济体来说,创新是一个关于存亡的问题。然而,由于我们普遍采用还原论的科学范式,发明和创新却很少被科学地研究。大多数工作更倾向于研究其背景及其成果。因此,在社会角度层面来看,缺乏科学工具来理解、改进或以其他方式影响发明和创新的过程。这本书深入探讨了这个话题,采取复杂的系统方法,其重点强调的“涌现”,是比我们的传统方法更现代的现象。在一个由欧盟资助的四年期国际研究小组的努力所产出的非常连贯的论文集中,它从不同的学科角度探讨了这个主题的各个方面。 一个主要的重点是,在社会科学中,如果我们想要理解社会进化,就需要从新达尔文主义的“人口思维”转向“组织思维”。另一个主要重点是开发发明和创新的生成方法,详细研究发明和创新发生的背景,以及这些背景如何影响成功或失败的机会。自始至终,这本书充满了有趣的新见解,但也提出了几个精心制定的案例研究,连接的想法与“现实世界”信息的实质性机构。本卷中介绍的研究由欧共体资助的项目 ISCOM (信息社会是一个复杂系统)开发,从两个基本前提出发:--指导创新政策,考虑到创新过程的社会、经济和地理方面至少与科学和技术同样重要; <br />
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标签:Agent-Based Modeling, Emergence, Complex Systems, Social Systems, Cooperation, Social Change, Social Science, Cities<br />
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作者:David Lane Denise Pumain Sander Ernst van der Leeuw [[杰弗里·韦斯特 Geoffery West]]<br />
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[[复杂性科学: 沃里克大师课程 Complexity Science: The Warwick Masters Course]](未建立词条)<br />
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复杂性科学是研究具有许多互相作用主体的系统的科学。复杂系统,以及它们所显现出来的自我组织和涌现的现象,是许多全球重要性挑战的核心。这本书介绍数学方法用来理解复杂性,与大量的例子和现实世界的应用。它从自我组织和涌现的关键概念开始,然后用微分方程和混沌理论推演动力系统的复杂性。利用随机分析技术研究了几类相互作用粒子系统模型,然后解释了复杂系统的统计力学。书籍进一步关注的主题包括偏微分方程的数值分析,以及随机方法在经济学和金融学中的应用。本书最后介绍了时空阶段和和自有路径。该综述适合研究人员,从业人员和复杂性科学及相关领域的本科及以上水平的学生阅读<br />
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标签:Complex Systems, Master's Program<br />
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作者:Robin Ball , Vassili Kolokoltsov Robert S. MacKay<br />
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[[复杂性、熵与信息物理学 Complexity, Entropy and the Physics of Information]](未建立词条)<br />
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这本书来自于1989年5月29日至6月2日在圣塔菲圣约翰学院举行的一次会议,由圣塔菲研究所的赞助举行的。官方参与者(大约40人)以及同样众多的“追随者”被上述“宣言”吸引到圣塔菲,像《复杂性、熵和信息物理学》这本书一样的会议不仅探讨了量子和传统 物理学之间的联系、信息及其改变、计算以及它们对物理理论形成的意义,而且还考虑了信息处理实体的起源和演化、它们的复杂性,以及它们分析自己的感知以形成宇宙模型的方式。事实上,这种程度的重叠是衡量会议成功与否的标准。这意味着对重要问题和预期答案的共识: 它们可能位于“边界区域”的某个地方,在那里信息、物理、复杂性、量子和计算都会相遇。<br />
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标签:Complex Systems, Information Theory, Thermodynamics, Physics, Entropy<br />
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作者:Wojciech H. Zurek<br />
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[[复杂 Complexity: A Guided Tour]](未建立词条)<br />
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蚂蚁在组成群体时为何会表现出如此的精密性和具有目的性?数以亿计的神经元是如何产生出像意识这样极度复杂的事物?是什么在引导免疫系统、互联网、全球经济和人类基因组等自组织结构?这些都是复杂系统科学尝试回答的迷人而令人费解的问题的一部分。<br />
理解复杂系统需要有全新的方法.需要超越传统的科学还原论,并重新划定学科的疆域。借助于圣塔菲研究所的工作经历和交叉学科方法,复杂系统的前沿科学家米歇尔以清晰的思路介绍了复杂系统的研究,横跨生物、技术和社会学等领域,并探寻复杂系统的普遍规律,与此同时,她还探讨了复杂性与进化、人工智能、计算、遗传、信息处理等领域的关系。<br />
此书中文版由湖南科技出版社出版<br />
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标签:Information Theory, Computation, Genetic Algorithms, Evolution, Biology, Cellular Automata, Computer Science, Chaos, Nonlinear Dynamics, Networks<br />
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作者:梅拉妮•米歇尔Melanie Mitchell<br />
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[[复杂性: 一则简介 Complexity: A Very Short Introduction]](未建立词条)<br />
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复杂性的重要性在霍金的评价中得到了很好的体现: “复杂性是21世纪的科学”。从鸟群的迁徙到互联网,环境的可持续性发展和市场调节,针对对复杂的非线性系统的研究和理解在过去30年中变得非常有影响力。 在这个非常简短的介绍中,该领域的领军人物之一,[[约翰·霍兰德 John Holland]],介绍了复杂性的关键要点和概念框架。从复杂的物理系统(如流体流动和预测天气) ,到复杂的适应系统(如高度多样化和相互依赖的热带雨林生态系统) ,他结合了人尽皆知的例子——亚当•斯密(Adam Smith)的针厂、达尔文(Darwin)的彗星兰花和西蒙(Simon)的“钟表匠”——以及复杂性理论所采用的涉及代理和瓮模型(不确定 )的方法<br />
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标签:Complex Systems <br />
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作者:[[约翰·霍兰德 John Holland]]<br />
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[[复杂性: 物理学中的层次结构和尺度 Complexity: Hierarchical Structures and Scaling in Physics]](未建立词条)<br />
这本书是关于复杂性的综合讨论,因为它出现在物理,化学和生物系统,以及在自然的数学模型之中。这本书旨在说明复杂性是如何展现的,并介绍一系列日益显性的数学方法对复杂行为进行分类。这本书将链接感兴趣的研究生和研究人员在物理学(非线性动力学,流体动力学,固体状态,元胞自动机,随机过程,统计力学和热力学) ,数学(动力系统,遍历和概率论) ,信息和计算机科学(编码,信息论和算法复杂性) ,电子工程和理论生物学上共同沟通学习。<br />
标签:Mathematics, Scaling, Philosophy, Statistical Physics<br />
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作者:Remo Badii<br />
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[[复杂性: 混沌边缘的生命 Complexity: Life at the Edge of Chaos]](未建立词条)<br />
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把世界上最好的科学作家与宇宙中最迷人的主题放在一起,你一定会写出一本精彩的书..。复杂性问题是一个至关重要且有争议的话题。这本书很重要,而且写得很漂亮。 ——“stephen Jay Gould”(复杂性)是我们在自然界和人类世界中发现的复杂性和组织性的奇妙结合: 细胞的运作、大脑的结构、股票市场的行为、政治权力的转移... ..。 这是时间科学... 思考的意义,以及计算信息..。 这是复杂性宣言的核心。 阅读它,思考它... ... 但不要忽视它。 <br />
——伊恩·斯图尔特,《自然》<br />
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标签:Complex Systems, Emergence, Chaos<br />
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作者:Roger Lewin<br />
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[[量子场论的概念基础 Conceptual foundations of quantum field theory]](未建立词条)<br />
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量子场论是描述物理世界的亚原子成分以及支配这些成分的法则和原理的强有力的语言。(这一段不确定)<br />
这本书包含最近的深入分析,由一组杰出的物理学家和技术哲学家来完成,我们目前对其概念基础的理解是有局限的,这种理解必须修订,以便理论可以走得更远。这些分析将是研究生和研究工作者在物理学内想知道的问题。这本书也会引起专业科学哲学家、历史学家和社会学家的兴趣,因为它包含了许多可以分析的材料,用于对本体论和方法论的反思,用于历史和文化分析,用于社会学分析各种因素。<br />
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标签:Physics<br />
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作者:Tian Yu Cao <br />
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[[预知社会:群体行为的内在法则 Critical Mass: How One Thing Leads to Another]](未建立词条)<br />
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是否有任何“自然法则”影响人类的行为和组织方式? ”? 在十七世纪,托马斯·霍布斯厌倦了肆虐英格兰的内战,他决定研究出一个稳定的社会需要什么样的政府。他的方法不是基于乌托邦式的一厢情愿的想法,而是基于伽利略从第一原则构建政府理论的机制。 他的解决方案对今天的社会没有吸引力,然而霍布斯在寻找“科学的”社会规则时,引发了一种新的思考人类行为的方式。 亚当斯密,康德,孔德和约翰·斯图尔特·密尔从不同的政治视角追求这一理念。 然而,渐渐地,社会和政治哲学抛弃了“科学”的方法。 今天,物理学正在社会、政治和经济科学中复兴。 鲍尔展示了当我们停止试图预测和分析个人的行为,转而关注个人决策——无论是在合作或冲突的情况下——对我们的法律、制度和习俗的影响时,我们对人类行为的了解有多少。 生动而引人注目的[[预知社会:群体行为的内在法则 Critical Mass: How One Thing Leads to Another]]是第一本将这些新思想融合在一起,并展示它们如何与理性寻找更好生活方式这一更广泛的历史背景相契合的书。<br />
标签:Dynamical Systems, Emergence<br />
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作者:Philip Ball<br />
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[[自然科学中的关键现象: 混沌、分形、自组织和无序 Critical phenomena in natural sciences: Chaos, fractals, self-organization, and disorder]](未建立词条)<br />
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在研究相关和不相关的现象时统计物理学的概念、方法和技术,越来越多地应用于自然科学、生物学和经济学,试图理解和模拟现象的巨大变化和风险。这是第一本由学者编写的教科书,为统计物理学以外的工作者提供了一个更现代的介绍。本书的重点是对概念和方法的清晰理解,同时也提供了可以在应用程序中直接使用的工具。<br />
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标签:Chaos, Fractals, Emergence, Biology, Self-Organization <br />
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作者:Didier Sornette<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%9B%BD%E9%99%85%E8%B4%B8%E6%98%93%E7%BD%91&diff=15168
国际贸易网
2020-10-14T13:54:38Z
<p>Thingamabob:创建页面,内容为“国际贸易网是指描述世界各国相互之间贸易关系的一种复杂网络模型,每个节点是一个参与贸易的国家,每条连边表示两…”</p>
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<div>国际贸易网是指描述世界各国相互之间贸易关系的一种[[复杂网络]]模型,每个节点是一个参与贸易的国家,每条连边表示两个国家之间的贸易,流量代表两国之间的贸易额。目前,已有大量的双边国际贸易数据存在,因此,人们可以构建非常完整的国际贸易网络。<br />
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=='''文献导读'''==<br />
===基于流网络探讨国际贸易中的多层网络<ref name="ShenBin">{{cite journal|last=Shen|first=Bin|first2=Jiang|last2=Zhang|first3=QiuHua|last3=Zheng|title=Exploring multi-layer flow network of international trade based on flow distances|year=2015|journal=Quantitative Finance}}</ref>===<br />
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文章概要:文章基于流网络的方法建立了分产品的多层贸易网络(关于流动网络的基础知识参见[[流动网络]]),并且定义了贸易网络中的货币流和物质流,在物质流中,商品从出口方流入进口方,源可以理解为各国国内的生产,汇可以看成各国的消费;相反货币流中,资金从进口国流向出口国,源是国内需求驱使下造成的贸易赤字,汇是国内的生产盈余。文章探究了不同国家在不同产品网络中的“生态位”(是更偏向于出口国(生产者)还是进口国(消费者)),即源到各国的距离的远近,以此衡量国家在流动网络中的重要性;发现了竞争力强的国家汇进出口更丰富的产品,相反竞争力弱的国家进出口产品的种类较少;提出了调和中心度的指标计算,在贸易网络中发现了中心分层的现象竞争力强的国家在多数产品贸易网络中占据中心位置,弱国在大多数产品贸易中都处在外围;发现了工业品的网络从源到汇的距离相比农业品从源到汇的距离更远。<br />
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===国际贸易流网络<ref name=" Shi, Peiteng">{{cite journal|last= Shi|first=Peiteng|first2=Jingfei|last2= Luo|first3=Penghao|last3=Wang|first4=Jiang |last4= Zhang|title=Centralized Flow Structure of International Trade Networks for Different Products|year=2013|journal=International Conference on Management Science & Engineering}}</ref>===<br />
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本文通过基于流网络建立国际贸易网络,观察2000年中800个产品的异速标度指数,发现大部分商品贸易网络大体上是中心化的。此外,该文作者将800种不同的产品都统一在一个坐标系下,更加直观地表示不同的商品大分类所具备的η值范围。结果表明大部分的工业产品在右侧,而农副产品产品在左侧。所以,说明工业品中性化更明显。<br />
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=='''数据来源及预处理'''==<br />
介绍两种与贸易相关的数据集及其预处理方法,最终得到加权的贸易邻接矩阵。<br />
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===NBER-UN数据集===<br />
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====数据来源及格式====<br />
* 国家经济研究局(National Bureau of Economic Research)提供了一套完整的从1962年到2000年的4位编码(SITC4)的国际贸易数据集,在每一年的数据中,有将近200个国家的近800种产品的双边贸易流量记录.[http://cid.econ.ucdavis.edu/nberus.html 下载链接]。<br />
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*原始数据为*.dta格式,matlab及python读取困难,需进行一步数据格式转换,存储为*.xlsx/*.xls/*.csv文件,进行矩阵处理与运算(可使用Stata进行格式转换处理,[http://pan.baidu.com/s/1kVhYYrX stata下载链接])。<br />
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*转换后的*.xlsx/*.xls/*.csv文件表格结构如下:<br />
[[File:internationaltradedata.png|800px]]<br />
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*数据格式:importer, exportor分别是进口国和出口国,sitc4是按照国际编码体系SITC4编码的产品种类,value是贸易额,unit是该商品的出口单位,quantity是该商品的出口数量。dot指代贸易流动方向,1=data is from importer,2=data is from exporter。例如:上图中第一条数据,Saudi Arabia在1986期间年从Turkey进口了sitc4编号为8510的产品,产品进口总额为248美元,共29公吨。<br />
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*关于SITC4编码的说明:SICT(Standard International Trade Classificatioon)为国际贸易标准分类方法,将贸易产品分为 10 大类(一位数)、66 章(二位数)、262(组(三位数)、1023 个分组(四位数)和 2652 个基本编号(五位数),具体内容请详见链接。[https://unstats.un.org/unsd/cr/registry/regcst.asp?Cl=8&Lg=1 SITC4]在本数据集中,有些SITC4编码以X、A等字母为结束,表示该商品的分类未有详细记录,或者是为了补全贸易数据人工添加的记录。<br />
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*关于该数据库的其他说明: 一国到世界(World)的出口或者进口并不一定等于一国到所有国家的出口或者进口,这是因为统计误差的存在。在数据下载链接中有"FQA on NBER-UN data"说明文档,如有更多其他问题,请参考。[http://cid.econ.ucdavis.edu/data/undata/FAQ_on_NBER-UN_data.pdf FQA on NBER-UN data]<br />
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====数据预处理====<br />
=====处理总贸易数据,得到贸易额列表=====<br />
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以62-00年各国不分产品总贸易额为例,逐年对NBER-UN国际贸易数据集进行分类汇总(该汇总列表由美国国家经济研究局NBER统计并整理,'''仅涵盖1962-2000年不分产品的贸易总额''',若研究分产品贸易网络,则需要按照个人需求从1962-2000年详具的39份年际贸易列表中逐年提取并汇总),按照1-202序列对全部202个国家重新编码(新编码Num代表该国在国际贸易矩阵中的行列号;'''注意,为保持贸易矩阵结构统一,此处的国家编码应与分产品贸易网的国家编码保持一致'''),汇总后整合表格结构如下:<br />
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[[File:62-00整合表格样例.JPG|800px]]<br />
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其中,Ecode表示出口国在NBER进行统计汇总时的原始代码,Icode表示进口国的原始代码,Num表示各国的新编码,即该国在国际贸易矩阵中的行列号,Value表示逐年的贸易总额(如:Value62表示1962年的出口国-进口国间的贸易总额)<br />
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以上预处理过后,可使用matlab及python读取贸易额并进行矩阵处理运算,预处理后的[http://pan.baidu.com/s/1nuPEcDb *.xlsx下载链接]<br />
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=====从总贸易额列表生成贸易矩阵(MATLAB代码)=====<br />
将预处理后的贸易列表(列表结构,共202个国家地区,*xlsx格式)调整至202*202贸易矩阵,并保存成*.xlsx格式,按照“年份.xlsx”格式命名。调整后的贸易矩阵[http://pan.baidu.com/s/1pKZJvth F下载链接],矩阵结构如下:<br />
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[[File:贸易矩阵F.JPG|800px]]<br />
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<syntaxhighlight lang="matlab"><br />
function [ F,country ] = nber2matrix( file,savepath,year )<br />
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%此函数用于:调整表格结构,将原始数据集(列表结构,共202个国家地区)调整至202*202贸易矩阵F,并保存成*.xlsx格式,按照“年份.xlsx”格式命名<br />
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%矩阵结构<br />
%第一列:出口国;第一行:进口国;单元格数值:出口国-进口国之间的贸易额<br />
<br />
%调用此函数前,需进行数据预处理,对贸易列表中的国家赋值唯一编码:<br />
%1.已有数据集:NBER62-00(数据来源:http://cid.econ.ucdavis.edu/nberus.html);<br />
%2.在原始数据集中(xlsx格式存储)新建sheet,自主编码(若有n个贸易国家,则自1到n编码)并赋值到列表中的每个国家(可使用excel中的index函数);<br />
<br />
%输入参数:<br />
%file:原始数据集路径+名称,char类型,如:'D:\dataset_NBER-UN\dta\wtf_bilat\NBER-UN_62-00.xlsx'<br />
%savepath:调整后的矩阵存储路径,char类型,如:'D:\dataset_NBER-UN\test\'<br />
%year:年份,double类型<br />
<br />
%输出参数:<br />
%F:贸易矩阵<br />
%country:原始数据集中的国家地区列表<br />
<br />
<br />
%读取贸易列表<br />
[data,textdata]=xlsread(file,1);<br />
%读取国家编码<br />
[num,country]=xlsread(file,2);<br />
%提取参与贸易的国家<br />
country=country(2:end,1);<br />
%将贸易列表调整至贸易矩阵F<br />
F=nan(size(country,1),size(country,1));<br />
for i=1:size(data,1)<br />
F(data(i,1),data(i,4))=data(i,year-1961+4);<br />
end<br />
<br />
%创建并存储贸易矩阵xlsx文档<br />
items={'Country'};%创建数据标题<br />
format='.xlsx';%设置存储格式<br />
sheet = sprintf(num2str(year)); %创建工作表<br />
xlsxname=num2str(year);%设置文档名称<br />
xlswrite([savepath xlsxname format], items, sheet);%创建xlsx文档<br />
range1 = sprintf('B2:%s%d',[char(double('A')+fix((size(F,2)/26))-1),char(double('A')+mod(size(F,2),26))],size(F,1)+1);%从F中获取贸易矩阵放置范围<br />
xlswrite([savepath xlsxname format], F(:,:), sheet, range1);%写入贸易总额<br />
range2 = sprintf('A2:%s%d','A',char(size(F,1)+1)); %从F中获取出口国的放置范围<br />
xlswrite([savepath xlsxname format], country(:,:), sheet, range2);%写入出口国<br />
range3 = sprintf('B1:%s%d',[char(double('A')+fix((size(F,2)/26))-1),char(double('A')+mod(size(F,2),26))],char(1)); %从F中获取进口国的放置范围<br />
xlswrite([savepath xlsxname format], country(:,:)', sheet, range3);%写入进口国<br />
<br />
end<br />
<br />
</syntaxhighlight><br />
<br />
=====处理分产品的贸易数据,直接得到贸易矩阵(Matlab代码)=====<br />
<br />
利用1962-2000年逐年详细贸易列表([http://pan.baidu.com/s/1nveAt7r 样例数据下载链接]),按列表结构如下图:<br />
<br />
[[File:1962年分产品贸易列表.JPG|600px]]<br />
<br />
进行一步预处理:新建sheet页,按照1-202序列对全部202个国家重新编码(编码可参考样例数据sheet2中的结构;'''注意,为保持贸易矩阵结构统一,此处的国家编码应与2.1.2.1贸易总额的国家编码保持一致''')<br />
<br />
预处理后,按照Sitc4编码提取产品,并调整为贸易矩阵F,保存成*.xlsx格式,按照“年份_SITC4码.xlsx”格式命名,代码如下: <br />
<br />
<syntaxhighlight lang="matlab"> <br />
function [ F,country ] = nber2matrix_sitc( file,savepath,sitc4 )<br />
<br />
%此函数用于:调整表格结构,将原始数据集(列表结构,共n个国家地区)分产品调整至n*n贸易矩阵,并保存成*.xlsx格式,按照“年份_SITC4码.xlsx”格式命名<br />
<br />
%矩阵结构<br />
%第一列:出口国;第一行:进口国;单元格数值:分产品出口国-进口国之间的贸易额<br />
<br />
%调用此函数前,需进行数据预处理,对贸易列表中的国家赋值唯一编码:<br />
%1.已有数据集:NBER62-00(数据来源:http://cid.econ.ucdavis.edu/nberus.html);<br />
%2.在原始数据集中(xlsx格式存储)新建sheet,自主编码(若有n个贸易国家,则自1到n编码);<br />
<br />
%输入参数:<br />
%file:原始数据集路径+名称,char类型,如:'D:\dataset_NBER-UN\dta\wtf_bilat\NBER-UN_62-00.xlsx'<br />
%savepath:调整后的矩阵存储路径,char类型,如:'D:\dataset_NBER-UN\test\'<br />
%sitc4:产品的Sitc4编码,char类型<br />
<br />
%输出参数:<br />
%F:贸易矩阵<br />
%country:原始数据集中的国家地区列表<br />
<br />
<br />
%读取贸易列表<br />
[data,textdata]=xlsread(file,1);<br />
%读取国家编码<br />
[num,country]=xlsread(file,2);<br />
%提取参与贸易的国家<br />
country=country(2:end,1);<br />
%将当年贸易网络中的国家与编码对应<br />
[tf_exp,index_exp]=ismember(textdata(2:end,5),country);<br />
[tf_imp,index_imp]=ismember(textdata(2:end,3),country);<br />
%按sitc4编码提取产品<br />
for i=1:size(textdata,1)-1<br />
sitc(i,1)=str2num(textdata{i+1,6});<br />
end<br />
re_data=[index_exp,index_imp,sitc,data(:,9)];<br />
sitc4=str2num(sitc4);<br />
[r,c]=find(re_data(:,3)==sitc4);<br />
re_data_sitc4=re_data(r,:);<br />
%将贸易列表调整至贸易矩阵F<br />
F=nan(size(country,1),size(country,1));<br />
for i=1:size(re_data_sitc4,1)<br />
if re_data_sitc4(i,1)~=0&&re_data_sitc4(i,2)~=0<br />
F(re_data_sitc4(i,1),re_data_sitc4(i,2))=re_data_sitc4(i,4);<br />
end<br />
end<br />
<br />
%创建并存储贸易矩阵xlsx文档<br />
items={'Country'};%创建数据标题<br />
format='.xlsx';%设置存储格式<br />
sheet = sprintf(num2str(data(1,1))); %创建工作表<br />
xlsxname=[num2str(data(1,1)),'_',num2str(sitc4)];%设置文档名称,以“年份_SITC4码”命名<br />
xlswrite([savepath xlsxname format], items, sheet);%创建xlsx文档<br />
range1 = sprintf('B2:%s%d',[char(double('A')+fix((size(F,2)/26))-1),char(double('A')+mod(size(F,2),26))],size(F,1)+1);%从F中获取贸易矩阵放置范围<br />
xlswrite([savepath xlsxname format], F(:,:), sheet, range1);%写入贸易总额<br />
range2 = sprintf('A2:%s%d','A',char(size(F,1)+1)); %从F中获取出口国的放置范围<br />
xlswrite([savepath xlsxname format], country(:,:), sheet, range2);%写入出口国<br />
range3 = sprintf('B1:%s%d',[char(double('A')+fix((size(F,2)/26))-1),char(double('A')+mod(size(F,2),26))],char(1)); %从F中获取进口国的放置范围<br />
xlswrite([savepath xlsxname format], country(:,:)', sheet, range3);%写入进口国<br />
<br />
end<br />
<br />
<br />
</syntaxhighlight><br />
<br />
<br />
调整后的分产品贸易矩阵如下:<br />
<br />
[[File:调整后的1962年分产品(SITC4编码:5222)贸易矩阵.JPG|600px]]<br />
<br />
===UN Comtrade数据集===<br />
====数据来源及结构====<br />
[https://comtrade.un.org/ UN Comtrade]<br />
<br />
[http://pan.baidu.com/s/1miNo2oS total trade in 2000]<br />
<br />
联合国商品贸易统计数据库(UN Comtrade Database)提供了一套完整的从1962年到2016年的国际贸易数据集。在每一年的数据中,有将近200个国家的产品双边贸易流量记录。<br />
<br />
该数据集的格式如下图所示: <br />
<br />
[[File:Trade.png|800px]]<br />
<br />
<br />
其中year表示年份,reporter和partner分别是贸易信息发布者和其贸易伙伴,trade flow是贸易流动方向,import和export分别是进口和出口,trade value是总贸易额。<br />
<br />
例如:上图中第二条数据,Ireland在2002年期间向Afghanistan出口了1674942美元的产品。<br />
<br />
====数据预处理====<br />
=====基于comtrade数据库的分产品贸易网络处理=====<br />
<br />
基本过程:<br />
分产品贸易流网络模型构建流程:<br />
1.从comtrade数据库中下载,需要的产品数据库<br />
由于comtrade数据库产品分类是海关编码HS,产品HS码查询:http://www.hsbianma.com/<br />
有了HS编码以后就可以在comtrade数据库中下载贸易数据了:<br />
注:选择你需要的年份、reporter,partners(这两个就是进出口国)、填入海关数据编码,就可以了。<br />
2.下载的数据类型是列表的形式,如上表所示<br />
需要注意:1.剔除贸易数据中reporter和partners为空白、world等数据。<br />
2.保留flow标识为1的数据<br />
3.完成1、2步骤以后,只保留reporter code、partners code以及value三列数据<br />
利用代码即可将编列表转换成矩阵的形式:Z=sparse(el(:,1)',el(:,2)',el(:,3)')(其中el是上述保留列表的矩阵名)<br />
<br />
=='''构建贸易流动网络方法及代码'''==<br />
===MATLAB代码===<br />
====步骤一、给贸易网络添加源汇====<br />
首先剔除贸易网络外的国家(不与其他任何国家进行进出口贸易),并添加源汇,调整至(m+2)*(m+2)平衡态贸易矩阵(共m个国家地区参与贸易网络,添加源汇各两行两列),保存成*.xlsx格式,并按照“年份_add_ss.xlsx”命名,添加源汇后的平衡贸易矩阵结构如下:<br />
<br />
[[File:平衡态F矩阵.JPG|800px]]<br />
<br />
<syntaxhighlight lang="matlab"><br />
<br />
<br />
function [ F_add_ss,country ] = add_source_sink( file,savepath,year )<br />
<br />
%此函数用于在贸易矩阵基础上,首先剔除贸易网络外的国家(不与其他任何国家进行进出口贸易),然后添加源汇,调整至(m+2)*(m+2)平衡态贸易矩阵(共m个国家地区参与贸易网络),保存成*.xlsx格式,并按照“年份_add_ss.xlsx”命名<br />
<br />
%矩阵结构<br />
%第一列:源+出口国+汇;第一行:源+进口国+汇;单元格数值:出口国-进口国之间的贸易额<br />
<br />
%调用此函数前,需首先调用nber2matrix函数,生成n*n贸易矩阵(NBER原始数据集共包含n个国家)<br />
<br />
%输入参数:<br />
%file:n*n贸易矩阵路径+名称,char类型,如:'D:\dataset_NBER-UN\test\1962.xlsx'<br />
%savepath:调整后的平衡贸易矩阵存储路径,char类型,如:'D:\dataset_NBER-UN\test\'<br />
%year:年份,double类型<br />
<br />
%输出参数:<br />
%F:平衡态贸易矩阵<br />
%country:参与贸易网络的m个国家地区列表<br />
<br />
<br />
%读取贸易矩阵<br />
[data,textdata]=xlsread(file,2);<br />
%补齐矩阵<br />
if size(data,1)~=(size(textdata,1)-1) <br />
data((size(data,1)+1):(size(textdata,1)-1),:)=nan;<br />
end<br />
if size(data,2)~=(size(textdata,2)-1)<br />
data(:,(size(data,2)+1):(size(textdata,2)-1))=nan;<br />
end<br />
%剔除异常值 <br />
for i=1:size(data,1)<br />
for j=1:size(data,2)<br />
if isnan(data(i,j))<br />
data(i,j)=0;<br />
end<br />
end<br />
end<br />
%剔除空行空列(存在空行或空列)<br />
r=find(any(data,2)==0);<br />
c=find(any(data,1)==0);<br />
d=union(r,c);<br />
data(d,:) = [];<br />
data(:,d) = [];<br />
%删除空行空列对应的国家<br />
textdata(d+1,:)=[];<br />
textdata(:,d+1)=[];<br />
data=[zeros(size(data,1),1),data,zeros(size(data,1),1)];<br />
data=[zeros(1,size(data,2));data;zeros(1,size(data,2))];<br />
%添加源汇;<br />
%“源-某国家”=“该国家总出口额”-“该国家总进口额”<br />
%“某国家-汇”=“该国家总进口额”-“该国家总出口额”<br />
for i=2:size(data,1)-1<br />
if sum(data(i,:))>sum(data(:,i))<br />
data(1,i)=sum(data(i,:))-sum(data(:,i));<br />
else<br />
data(i,end)=sum(data(:,i))-sum(data(i,:));<br />
end<br />
end<br />
F_add_ss=data;<br />
%创建并存储贸易矩阵xlsx文档<br />
xlsname=[num2str(year),'_add_ss'];%设置文档名称<br />
sheet= sprintf(num2str(year)); %创建工作表<br />
format='.xlsx';%设置存储格式<br />
items=' country';%创建数据标题<br />
xlswrite([savepath xlsname format], items, sheet);%创建xlsx文档<br />
country=[[cell(1,1),'Source',textdata(1,2:end),'Sink'];[['Source';textdata(2:end,1);'Sink'],cell(size(F_add_ss,1),size(F_add_ss,2))]];%在国家列表中源汇各一行一列<br />
range1 = sprintf('B2:%s%d',[char(double('A')+fix((size(F_add_ss,2)/26))-1),char(double('A')+mod(size(F_add_ss,2),26))],size(F_add_ss,1)+1); %从源文件中获取的贸易额的放置范围<br />
xlswrite([savepath xlsname format], F_add_ss, sheet, range1);%写入贸易额<br />
range2 = sprintf('A1:%s%d','A',size(country,1)); %从源文件中获取的出口国的放置范围<br />
xlswrite([savepath xlsname format], country(:,1), sheet, range2);%写入出口国<br />
range3 = sprintf('A1:%s%d',[char(double('A')+fix((size(F_add_ss,2)/26))-1),char(double('A')+mod(size(F_add_ss,2),26))],1); %从源文件中获取的进口国的放置范围<br />
xlswrite([savepath xlsname format], country(1,:), sheet, range3);%写入进口国<br />
<br />
end<br />
<br />
<br />
<br />
<br />
</syntaxhighlight><br />
<br />
====步骤二、形成源-国家、国家-汇的首达距离列表L====<br />
<br />
在平衡态贸易矩阵基础上,计算各国家地区之间的首达距离,并形成源-国家、国家-汇的首达距离列表L,存储成*.xlsx格式,并按照“年份_L.xlsx”命名,L列表结构如下:<br />
<br />
[[File:L列表样例.JPG|800px]]<br />
<br />
<syntaxhighlight lang="matlab"><br />
<br />
<br />
function [ L_all,L,country ] = F2L( file,savepath,year )<br />
<br />
%此函数用于:在平衡态贸易矩阵基础上,计算各国家地区之间的首达距离L_all,并形成源-国家、国家-汇的首达距离列表L<br />
<br />
%首达距离列表结构<br />
%第一列:国家名称;第二列:源-国家的首达距离;第三列:国家-汇的首达距离<br />
<br />
%调用此函数前,需首先调用add_source_sink函数,生成(m+1)*(m+1)平衡态贸易矩阵(共m个国家地区参与进贸易网络)<br />
<br />
%输入参数:<br />
%file:(m+1)*(m+1)平衡态贸易矩阵路径+名称,char类型,如:'D:\dataset_NBER-UN\test\1962_ass_ss.xlsx'<br />
%savepath:首达距离列表L存储路径,char类型,如:'D:\dataset_NBER-UN\test\'<br />
%year:年份,double类型<br />
<br />
%输出参数:<br />
%L_all:各国家地区之间的首达距离矩阵<br />
%L:源-国家、国家-汇的首达距离列表<br />
%country:参与贸易网络的m个国家地区列表<br />
<br />
%读取平衡态贸易矩阵<br />
[data,textdata]=xlsread(file,2);<br />
%计算概率转移矩阵M<br />
F=data;<br />
a=sum(F,2);<br />
for i=1:size(F,1);<br />
for j=1:size(F,2);<br />
if i<size(F,1);<br />
M(i,j)=F(i,j)/a(i,1);<br />
else<br />
M(i,j)=0;<br />
end<br />
end<br />
end<br />
%计算基础矩阵U<br />
U=inv(eye(size(M,1))-M); <br />
M1=M*U^2;<br />
%计算均首达距离矩阵L_all<br />
for i=1:size(U,1) <br />
for j=1:size(U,2)<br />
L_all(i,j)=M1(i,j)/U(i,j)-M1(j,j)/U(j,j);<br />
end<br />
end<br />
%提取源-国家、国家-汇首达距离列表L<br />
L=[L_all(1,2:(size(L_all,2)-1))',L_all(2:(size(L_all,1)-1),end)]; <br />
NBER_L{1,1}=num2str(year);<br />
NBER_L{2,1}=textdata(1,3:end-1)';<br />
NBER_L{3,1}=L;<br />
country=NBER_L{2,1};<br />
%创建并存储首达距离列表xlsx文档<br />
xlsname=[num2str(year),'_L'];%设置文档名称<br />
sheet= sprintf(num2str(year));%创建工作表<br />
format='.xlsx';%设置存储格式<br />
items={'country','source to country','country to sink'};%创建数据标题<br />
xlswrite([savepath xlsname format], items, sheet);%创建xlsx文档<br />
<br />
xlswrite([savepath xlsname format], NBER_L{2,1} , sheet,'A2'); %在第一列写入国家<br />
range = sprintf('B2:%s%d',char(double('B')+size(NBER_L{3,1},2)-1), size(NBER_L{3,1},1)+1); %从首达距离列表中获取的距离放置位置<br />
xlswrite([savepath xlsname format], NBER_L{3,1}, sheet, range);%写入距离<br />
<br />
end<br />
<br />
<br />
<br />
</syntaxhighlight><br />
<br />
====步骤三、计算各国家地区之间C矩阵====<br />
<br />
去除贸易网络进出口方向性,进行一步对称处理,得到无向贸易流网络C,存储成*.xlsx格式,并按照“年份_C.xlsx”命名<br />
<br />
[[File:C矩阵样例.JPG|800px]]<br />
<br />
<syntaxhighlight lang="matlab"><br />
<br />
<br />
function [ C,country ] = F2C( file,savepath,year )<br />
<br />
%此函数用于:在平衡态贸易矩阵基础上,计算各国家地区之间C矩阵<br />
<br />
%输入参数:<br />
%file:(m+1)*(m+1)平衡态贸易矩阵路径+名称,char类型,如:'D:\dataset_NBER-UN\test\1962_add_ss.xlsx'<br />
%savepath:首达距离列表L存储路径,char类型,如:'D:\dataset_NBER-UN\test\'<br />
%year:年份,double类型<br />
<br />
%输出参数:<br />
%C:对称矩阵C<br />
%country:参与贸易网络的m个国家地区列表<br />
<br />
<br />
<br />
%读取平衡态贸易矩阵<br />
[data,textdata]=xlsread(file,2);<br />
%计算概率转移矩阵M<br />
F=data;<br />
a=sum(F,2);<br />
for i=1:size(F,1);<br />
for j=1:size(F,2);<br />
if i<size(F,1);<br />
M(i,j)=F(i,j)/a(i,1);<br />
else<br />
M(i,j)=0;<br />
end<br />
end<br />
end<br />
%计算基础矩阵U<br />
U=inv(eye(size(M,1))-M); <br />
M1=M*U^2;<br />
%计算均首达距离矩阵L_all<br />
for i=1:size(U,1) <br />
for j=1:size(U,2)<br />
L_all(i,j)=M1(i,j)/U(i,j)-M1(j,j)/U(j,j);<br />
end<br />
end<br />
L_all(:,1)=conj(L_all(1,:));<br />
L_all(size(L_all,1),:)=conj(L_all(:,size(L_all,2)));<br />
%计算C矩阵<br />
for i=1:size(L_all,1) <br />
for j=1:size(L_all,2)<br />
C(i,j)=2*1/(1/L_all(i,j)+1/L_all(j,i));<br />
end<br />
end<br />
%创建并存储首达距离列表xlsx文档<br />
xlsname=[num2str(year),'_C'];%设置文档名称<br />
sheet= num2str(year);%创建工作表<br />
format='.xlsx';%设置存储格式<br />
items=' country';%创建数据标题<br />
xlswrite([savepath xlsname format], items, sheet);%创建xlsx文档<br />
country=textdata;<br />
<br />
range1 = sprintf('B2:%s%d',[char(double('A')+fix((size(C,2)/26))-1),char(double('A')+mod(size(C,2),26))],size(C,1)+1); %从源文件中获取的对称矩阵C的放置范围<br />
xlswrite([savepath xlsname format], C, sheet, range1);%写入C矩阵<br />
range2 = sprintf('A1:%s%d','A',size(country,1)); %从源文件中获取的出口国的放置范围<br />
xlswrite([savepath xlsname format], country(:,1), sheet, range2);%写入出口国<br />
range3 = sprintf('A1:%s%d',[char(double('A')+fix((size(C,2)/26))-1),char(double('A')+mod(size(C,2),26))],1); %从源文件中获取的进口国的放置范围<br />
xlswrite([savepath xlsname format], country(1,:), sheet, range3);%写入进口国<br />
<br />
end<br />
<br />
<br />
<br />
</syntaxhighlight><br />
<br />
==参考文献==<br />
<br />
<references/><br />
<br />
<br />
[[category:流网络]]<br />
[[category:国际贸易]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%94%90%C2%B7%E6%89%98%E6%96%AF%E5%88%A9_Don_Towsley&diff=15166
唐·托斯利 Don Towsley
2020-10-14T13:53:31Z
<p>Thingamabob:创建页面,内容为“==基本信息== 右 姓名:Don Towsley(唐·托斯利) 出生:1949年 国籍:美国 母校:德克萨斯…”</p>
<hr />
<div>==基本信息==<br />
[[File:Don Towsley.jpg|缩略图|右]]<br />
<br />
姓名:Don Towsley(唐·托斯利)<br />
出生:1949年<br />
国籍:美国<br />
母校:德克萨斯大学大学<br />
学位:物理学学士学位和博士学位;德克萨斯大学的计算机科学学位<br />
研究方向:网络测量,建模和分析<br />
<br />
==博士生导师==<br />
<br />
K. Mani Chandy(K.玛尼·昌迪)<br />
<br />
==学生==<br />
<br />
张志立<br />
<br />
== 就职企业、机构或院校 ==<br />
<br />
特聘教授在计算机科学系在马萨诸塞大学-阿默斯特, 在那里他共同指导[http://gaia.cs.umass.edu/ 网络研究实验室]。<br />
<br />
Towsley教授是AT&T Labs-Research,IBM Research,INRIA,Microsoft Research Cambridge和Paris 6大学的客座科学家 。<br />
<br />
目前担任IEEE / ACM网络事务主编以及《 ACM 杂志》和《 IEEE通信领域的精选杂志》的编委。他目前是IFIP关于计算机性能测量,建模和分析的7.3工作组主席。他还曾在多个编辑委员会任职,其中包括IEEE Transactions on Communications and Performance Evaluation的编辑委员会。。他多年来一直活跃在众多会议的程序委员会中,包括IEEE Infocom,ACM SIGCOMM,ACM SIGMETRICS和IFIP Performance会议,并曾担任ACM SIGMETRICS和Performance会议的技术程序联席主席。<br />
<br />
==成就==<br />
<br />
曾获得2007年IEEE小林Keji电脑和通信奖,1999年IEEE通信学会William Bennett奖。,以及多个会议/研讨会最佳论文奖。他还是马萨诸塞州大学总理奖章的获得者和马萨诸塞州大学自然科学与数学学院的杰出研究奖。他是计算机性能基金会的创始人之一。他曾两次获得IBM院士奖学金,并且是IEEE和ACM的院士。<br />
<br />
== 主要文章及著作 ==<br />
<br />
* [https://dlacm.xilesou.top/citation.cfm?id=285291 Modeling TCP throughput: A simple model and its empirical validation] 《TCP吞吐量建模:一个简单模型及其经验验证》,1998,被引3286次<br />
* [https://dlacm.xilesou.top/citation.cfm?id=347421 Fluid-based analysis of a network of AQM routers supporting TCP flows with an application to RED] 《对支持TCP流的AQM路由器网络基于流体的分析及其RED应用》,2000,被引1868次<br />
* [On designing improved controllers for AQM routers supporting TCP flows https://ieeexplore.ieee.org/abstract/document/916670/ ] 《为支持TCP流的AQM路由器设计改进的控制器时》,2001,引用1447次<br />
<br />
== 联系方式 ==<br />
<br />
* 地址:Department of Computer Science, University of Massachusetts, Amherst MA 01003 USA, towsley at cs dot umass dot edu<br />
* 电话: 413-545-0207<br />
* 传真: 413-545-1249<br />
<br />
== 相关链接 ==<br />
<br />
[http://infocom2007.ieee-infocom.org/keynote.html 个人主页]<br />
<br />
[https://web.cs.umass.edu/csinfo/announce/towsleyieee.html Towsley获得著名的IEEE奖]<br />
<br />
[https://en.wikipedia.org/wiki/Don_Towsley WIKI主页]<br />
<br />
[https://scholar.google.com/citations?user=KIFPVWoAAAAJ&hl=zh-CN 谷歌学术]<br />
[[Category:网络科学]] <br />
[[Category:人物]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%8F%B2%E9%9B%AA%E6%9D%BE&diff=15165
史雪松
2020-10-14T13:52:33Z
<p>Thingamabob:创建页面,内容为“==基本信息== 右 ===史雪松简介=== <big>* 英特尔中国研究院高级研究员 * 复旦大学电子工程系博…”</p>
<hr />
<div>==基本信息==<br />
[[File:史雪松.jpg|400px|缩略图|右]]<br />
===史雪松简介===<br />
<big>* 英特尔中国研究院高级研究员<br />
* 复旦大学电子工程系博士</big><br />
<br/><br />
<br/><br />
==学术背景==<br />
目前研究方向为三维视觉、深度学习和异构计算。参与英特尔中国研究院HERO机器人计算平台设计和优化,主导FAST Mapping稠密建图软件研发,曾于信号处理和机器人学的主流学术会议与期刊上发表文章,拥有多项机器人和人工智能方向的专利申请。<br />
<br/><br />
<br/><br />
===研究领域===<br />
* 视觉定位与三维地图构建(SLAM)<br />
* 机器人运动规划算法<br />
* 图信号处理理论与图滤波算法<br />
<br/><br />
<br/><br />
==曾授课程==<br />
* 支持向量机<br />
* 图信号处理<br />
* 强化学习<br />
* 卷积神经网络<br />
* 机器人空间智能<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%8F%82%E4%B8%8E%E7%9A%842050&diff=15164
参与的2050
2020-10-14T13:51:59Z
<p>Thingamabob:创建页面,内容为“这是一个预测、规划、参与未来的游戏;也是一个多学科相互交叉合作的研究项目。我们的目的就是为了预测、规划、影响205…”</p>
<hr />
<div>这是一个预测、规划、参与未来的游戏;也是一个多学科相互交叉合作的研究项目。我们的目的就是为了预测、规划、影响2050年人类社会乃至世界的走向。<br />
<br />
==项目背景==<br />
<br />
2050年的人类社会是什么样子的?在[[走近2050]]这本书中,我们从注意力的角度解读了互联网现象,重新审视了人-机关系,对人类社会进行了畅想。特别是,在书中的最后一个故事中,我们描述了2050年世界的样子。<br />
<br />
然而,这种想象还远远不够。首先,如果我们要想真的刻画出2050年人类社会,乃至世界的样子,不能简单地靠拍脑袋来决定。因为,2050年的世界显然是一个非常复杂的巨系统,它会受到人类社会、政治、经济、文化、环境等各个子系统的影响。同时,人类的发展遵循非线性效应,因此,我们不可能从单一方面的外推来考虑整个未来世界的发展。<br />
<br />
基于这些考虑,我们有必要把对2050年世界的想象、预测,甚至是干预看作一个系统工程。我们要邀请各个行业的经营共同参与其中,共同规划未来。同时,我们会配合计算机模拟技术,来共同打造一个设计未来的游戏。这就是这个项目的起源。<br />
<br />
我们每个人都是2050的参与者,我们有权利根据自己的想象来构建2050的世界。于是,“参与的2050”(Participated 2050)这个项目就诞生了。我们需要大家一起参与进来,共同预测、规划2050年的样子。<br />
<br />
===关于未来学===<br />
<br />
本项目研究应该属于未来学的范畴。根据维基百科上的定义,所谓的未来学(Futurology)是指一种对可能、偏好的未来进行推测的一种学问。究竟未来学属于人文还是社会科学一直是人们争论的焦点。一般而论,它属于与历史学相平行的社会科学的一个分支。<br />
<br />
未来学运用大量的系统科学研究方法,包括动力系统、计算机模拟、头脑风暴法、Delphi方法、层次分析方法等等,来对未来进行预测。<br />
<br />
历史上,著名的未来学研究包括“增长的极限”、“奇点临近”、“第三次浪潮”等等。<br />
<br />
==项目意义==<br />
<br />
无论是社会人文科学还是自然科学,它们的终极目标都是为了更好地预测未来。反过来说,是否能够更加合理、准确地预测未来也是检验我们对科学的掌握程度的最好标准。所以,“参与的2050”这个项目的意义就在于我们可以通过设定一个宏大目标——预测2050年的人类未来,来检验项目参与者所掌握的科学知识和技能。<br />
<br />
2050年并不是一个过分遥远的未来。我们相信,几乎每一个本项目的参与者都有机会亲眼看到2050年时候的真正模样。所以,我们的所有研究成果都可以在那个时候得到检验。所以,这更像是一场实验,而不仅仅是一场与现实无关的游戏。<br />
<br />
另外一方面,正如我们的标题,我们每个人都显然是2050世界的一部分,都是一个参与者。这也就意味着,我们的所做所为很有可能会真的改变2050年的世界。假如在这个项目中,诞生了非常好玩的创意或者是让人意想不到的预言,那么我们的研究成果是真的会影响未来社会的发展走向的。正如当年罗马俱乐部曾经预测人类社会将出现大危机,从而导致了很多人郁郁而死一样,我们的预言也可能有着同样的震撼效果。<br />
<br />
==具体玩法==<br />
<br />
我们初步构思是通过一种人-机结合的方式,多学科反复交叉地推演未来世界的走向。在初期,我们会形成一个由多个学科学者共同参与的研讨小组,共同制定一些基本规则。整个系统的模拟需要划分为多个模块,比如气候模块。在这个模块中,气像学专家就可以预测一下未来几十年的气候变化大趋势会怎么样。将气候模块得出来的结论作为一种基本的环境变量设定,再放到其他模块中。例如,可以将气候变化的各种参数设定为全球生态系统演化的条件。之后,生态学家开始根据这些设定推演未来几十年的生态系统变化。<br />
<br />
与此类似,我们可以不断地从更宏大的系统独立推演得出参数,然后放置到这个系统能够影响的子系统中。然后推演子系统。当然,有的子系统会反过来影响父系统,因此,整个系统需要反复不停地迭代。具体的流程可以如下图所示:<br />
<br />
[[File:2050-couplingofsubsystems.png|150px]]<br />
<br />
在每一个推演的环节,我们都需要采用定性与定量相结合、计算机模拟与人类的参与相结合的方式来进行。<br />
<br />
从上往下,沿着相互影响箭头每执行一次,就称为一轮仿真。一轮仿真的时间周期可以很长(数月甚至一年)。在每轮结束后可以组织衍生品产出,包括:<br />
<br />
* 具体的技术发明<br />
* 科幻小说<br />
<br />
在宏大叙事下,展开细节的小发明和小故事,会让人印象深刻。<br />
<br />
==成果呈现==<br />
<br />
我们的成果将以如下形式体现:<br />
<br />
# 不定期的人类发展报告(要用纪实文学的形式、要具体)<br />
# 新环境下的技术发明(应以专利的形式体现)<br />
# 科幻小说若干<br />
<br />
==子系统(学科)划分==<br />
<br />
在此,我们根据维基百科上的科学的领域划分给出了各个子系统的分级。根据这种划分,人类的科学知识总共分为:人文、社会、自然、形式四大学科。按照和本项目的关系密切程度来做排序,顺序应该是:自然、社会、形式、人文。<br />
<br />
在其中,自然科学又分为了:生物、化学、地球科学、物理学、空间科学,以及农业、工程与技术、环境科学、医疗与健康、运动科学这几个专业学科。根据笔者的理解,除去化学、物理学这样的基础学科以外,这些学科从宏观到微观对本项目的影响排序应该是:空间科学、地球科学、环境科学、农业科学、生物、工程与技术、医疗与健康、运动科学。<br />
<br />
下面,我们根据这些学科划分,从宏观到微观,详细论述与本项目有关的子学科<br />
<br />
===空间科学===<br />
<br />
该学科主要探讨与宇宙航行、空间探索有关的学科,它包括如下分支:<br />
<br />
# 天体生物学<br />
# 天文学<br />
# 天体物理学<br />
……<br />
<br />
===地球科学===<br />
<br />
所有与地球、地理相关的学科分支,包括:<br />
<br />
# 地质学<br />
# 行星学<br />
# 水力学<br />
# 冰川学<br />
……<br />
<br />
===环境科学===<br />
<br />
环境科学是一种包含了物理、生物、信息科学的交叉学科领域,它的主要研究对象就是我们的生存环境,解决环境问题是其核心目标。环境科学主要包括:<br />
<br />
# 大气科学<br />
# 生态学<br />
# 环境化学<br />
# 地球科学<br />
<br />
这四大领域。<br />
<br />
===工程与技术===<br />
<br />
可以说工程与技术是人类改造地球、改造社会的一种最主要的学科门类,它对我们预测2050年的世界与人类社会起着至关重要的作用。下面我们列出一些可能与本项目研究有关的学科领域。<br />
<br />
* 化学工程<br />
*: 材料工程<br />
===工程与技术===<br />
<br />
可以说工程与技术是人类改造地球、改造社会的一种最主要的学科门类,它对我们预测2050年的世界与人类社会起着至关重要的作用。下面我们列出一些可能与本项目研究有关的学科领域。<br />
<br />
* 化学工程<br />
*: 材料工程<br />
*: 分子工程<br />
*: 纳米技术<br />
* 土木建筑<br />
*: 交通运输工程<br />
*: 环境工程<br />
*: 矿业工程<br />
*: 结构工程<br />
* 电气工程<br />
*: 计算机工程<br />
*: 计算机科学<br />
*: 信息理论<br />
*: 量子计算<br />
*: 机器人<br />
*: 半导体<br />
* 材料科学与工程<br />
*: 生物材料<br />
*: 纳米材料<br />
* 机械工程<br />
* 生物医药工程<br />
* 机器人<br />
* 车辆运输工程<br />
<br />
要注意的是,这种人为的分割仅仅是一种权宜之计。事实上,所有这些学科、子系统都是相互耦合的。因此,在模拟的过程中,我们需要综合考虑各种因素。<br />
<br />
==实施步骤==<br />
<br />
===形成项目筹备委员会===<br />
<br />
由3到5个核心成员形成项目筹备委员会,职责是制定游戏的规则,召集活动参与者,负责、保证项目的实施。<br />
<br />
===形成专业委员会===<br />
<br />
由10-20人组成,来自各个领域的专家。大家通过研讨和交流,形成具体的项目实施方案。<br />
<br />
===建立模型进行推演===<br />
<br />
根据专业委员会讨论形成的具体方案,建立模型,进行推演。这里的模型是指人-机结合的模型。<br />
<br />
Hey, that's powurfel. Thanks for the news.<br />
<br />
===形成故事===<br />
<br />
根据模拟的结果,招募大量的志愿者,形成在这个设定下的具体故事。希望对未来世界形成更具体、饱满的描述。<br />
<br />
==参考资料==<br />
<br />
===2050人类大迁徙===<br />
[[File:1ad5ad6eddc451da07216bb8b6fd5266d1163289.jpg|300px]]<br />
<br />
罗伦斯·史密斯写的《2050人类大迁徙》是一本与本项目主题最接近的一本书,该书主要从气候、人口全球经济的角度构思、预测了人类社会的未来。但是,本书唯一的不足是作者认为技术的力量并不足矣克服全球气候、人口增长、资源消耗的速度。<br />
<br />
然后,从另一个角度说,《2050人类大迁徙》恰恰形成了《[[走近2050]]》的一个补充,因为前者主要从地理、环境、生态的角度探索地球的发展,而后者则主要从人工智能、虚拟现实等技术的角度来外推。<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%8C%B9%E9%85%8D%E7%94%9F%E9%95%BF%E6%A8%A1%E5%9E%8B&diff=15163
匹配生长模型
2020-10-14T13:50:41Z
<p>Thingamabob:</p>
<hr />
<div>==模型设定==<br />
===基本规则===<br />
<br />
[[File:machingmodelillustration.PNG|300px]]<br />
<br />
[[File:Machingmodelrunniing.PNG|缩略图|default]]<br />
<br />
在一个d为欧几里德空间中,随机地加入一个点。<br />
<br />
==模型分析==<br />
{| class="wikitable"<br />
|-<br />
! 条目 !! 姓名 !! 标题文字<br />
|-<br />
| 1|| 2|| 3<br />
|-<br />
| 示例 || 示例 || 示例<br />
|-<br />
| 示例 || 示例 || 示例<br />
|}<br />
<br />
<math><br />
E\sim N^{\frac{d+2}{d+1}}<br />
</math><br />
<br />
==模型结果==<br />
<br />
==实证数据==<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%88%A9%E7%94%A8python%E7%9A%84theano%E5%BA%93%E5%88%B7kaggle_mnist%E6%8E%92%E8%A1%8C%E6%A6%9C&diff=15162
利用python的theano库刷kaggle mnist排行榜
2020-10-14T13:50:09Z
<p>Thingamabob:创建页面,内容为“==背景== theano 是一个python语言的库,实现了一些机器学习的方法,最大的特点是可以就像普通的python程序一样透明的使用GPU t…”</p>
<hr />
<div>==背景==<br />
theano 是一个python语言的库,实现了一些机器学习的方法,最大的特点是可以就像普通的python程序一样透明的使用GPU<br />
theano的主页:http://deeplearning.net/software/theano/index.html<br />
theano 同时也支持符号计算,并且和numpy相容,numpy是一个python的矩阵计算的库,可以让python具备matlab的计算能力,虽然没有matlab方便<br />
numpy的主页:http://www.numpy.org/<br />
MNIST是一个手写数字识别的公开数据集,我以为地球人都知道<br />
<br />
http://kaggle2.blob.core.windows.net/competitions/kaggle/3004/logos/front_page.png<br />
mnist主页:http://yann.lecun.com/exdb/mnist/<br />
<br />
其他大部分资源位于deeplearning向导的主页:<br />
deeplearning.net向导: http://deeplearning.net/tutorial/<br />
<br />
kaggle是一个供大家公开测试各种机器学习算法的平台,包括ICML和KDD cup一类的比赛都在上面进行,其中的入门测试集就是MNIST:<br />
kaggle的MNIST主页:http://www.kaggle.com/c/digit-recognizer<br />
<br />
目前发表的最好结果是卷积神经网络方法的0.23%错误率<ref name="mnist homepage">http://yann.lecun.com/exdb/mnist/, mnist homepage<br />
</ref>,kaggle上被认可的最好结果是0.5%。看这个架势,mnist已经基本被大家解决了。不过本着实践出真知和学习threano用法的目的,我觉得用python的theano库对kaggle mnist刷个榜玩玩也不错。<br />
<br />
==数据转换与代码修改==<br />
theano的代码位于: <br />
https://github.com/lisa-lab/DeepLearningTutorials<br />
我修改后的代码位于:<br />
https://github.com/chaosconst/DeepLearningTutorials<br />
<br />
===输入数据修改===<br />
原来是从cPickle导入:<br />
<br />
<syntaxhighlight lang="python"><br />
#############<br />
# LOAD DATA #<br />
#############<br />
<br />
# Download the MNIST dataset if it is not present<br />
data_dir, data_file = os.path.split(dataset)<br />
if (not os.path.isfile(dataset)) and data_file == 'mnist.pkl.gz':<br />
import urllib<br />
origin = 'http://www.iro.umontreal.ca/~lisa/deep/data/mnist/mnist.pkl.gz'<br />
print 'Downloading data from %s' % origin<br />
urllib.urlretrieve(origin, dataset)<br />
<br />
print '... loading data'<br />
<br />
# Load the dataset<br />
f = gzip.open(dataset, 'rb')<br />
train_set, valid_set, test_set = cPickle.load(f)<br />
f.close()<br />
</syntaxhighlight><br />
<br />
更改为读取train.csv和test.csv,先初始化四个list。<br />
<syntaxhighlight lang="python"><br />
print '... loading data'<br />
train_set=list();<br />
valid_set=list();<br />
test_set=list();<br />
predict_set=list();<br />
</syntaxhighlight><br />
valid_set是用来在SGD迭代过程中,用来验证效果但不参与训练的数据集。每次只有确定在valid_set上更有效,才继续进行目标函数的优化,这样可以防止过拟合。参见early-stopping<ref>http://deeplearning.net/tutorial/gettingstarted.html#early-stopping</ref>。<br />
<br />
设定数据集的大小,如果是调试模式则减小数据集。<br />
<syntaxhighlight lang="python"><br />
train_set_size = 36000;<br />
valid_set_size = 5000;<br />
test_set_size = 1000;<br />
predict_set_size = 28000;<br />
<br />
debug = "false";<br />
if debug == "true":<br />
train_set_size = 3600;<br />
valid_set_size = 500;<br />
test_set_size = 100;<br />
predict_set_size = 2800;<br />
</syntaxhighlight><br />
MNIST共有7w条记录,其中6w是训练集,1w是测试集。theano的样例程序就是这么做的,但kaggle把7w的数据分成了两部分,train.csv一共42000行,test.csv一共28000行。实际可用来训练的数据只有42000行(由此估计最后的效果也会有相应的折扣)。theano把6w的训练集分为了5w的test_set和1w的valid_set,我在这里把42000行数据分为36000的train_set、5000行的valid_set和1000行的test_set(训练时用不到)。<br />
<br />
另外我建了一个predict_set,用来保存准备提交给kaggle的数据。然后我进行了变量初始化并从文件读取数值,读取的时候把kaggle的int转化成了theano需要的float。<br />
<syntaxhighlight lang="python"><br />
<br />
train_set.append(numpy.ndarray(shape=(train_set_size,28*28), dtype=theano.config.floatX));<br />
train_set.append(numpy.ndarray(shape=(train_set_size), dtype=int));<br />
valid_set.append(numpy.ndarray(shape=(valid_set_size,28*28), dtype=theano.config.floatX));<br />
valid_set.append(numpy.ndarray(shape=(valid_set_size), dtype=int));<br />
test_set.append(numpy.ndarray(shape=(test_set_size,28*28), dtype=theano.config.floatX));<br />
test_set.append(numpy.ndarray(shape=(test_set_size), dtype=int));<br />
predict_set.append(numpy.ndarray(shape=(predict_set_size,28*28), dtype=theano.config.floatX));<br />
predict_set.append(numpy.ndarray(shape=(predict_set_size), dtype=int));<br />
<br />
#load data from kaggle test set<br />
with open('train.csv', 'rb') as csvfile:<br />
datareader = csv.reader(csvfile, delimiter=',')<br />
index=0;<br />
for row in datareader:<br />
if index<train_set_size : <br />
train_set[1][index] = string.atoi(row[0]);<br />
for pixel_index in xrange(1,28*28+1) : <br />
train_set[0][index][pixel_index-1] = string.atof(row[pixel_index])/255;<br />
elif index < train_set_size + valid_set_size :<br />
valid_set[1][index-train_set_size] = string.atoi(row[0]);<br />
for pixel_index in xrange(1,28*28+1) : <br />
valid_set[0][index-train_set_size][pixel_index-1] = string.atof(row[pixel_index])/255;<br />
else :<br />
test_set[1][index-train_set_size-valid_set_size] = string.atoi(row[0]);<br />
for pixel_index in xrange(1,28*28+1) : <br />
test_set[0][index-train_set_size-valid_set_size][pixel_index-1] = string.atof(row[pixel_index])/255;<br />
index+=1;<br />
if index == train_set_size + valid_set_size + test_set_size : <br />
break; <br />
<br />
print '... loading predict dataset'<br />
#load data from kaggle test set<br />
with open('test.csv', 'rb') as csvfile:<br />
datareader = csv.reader(csvfile, delimiter=',')<br />
index=0;<br />
for row in datareader:<br />
for pixel_index in xrange(0,28*28) : <br />
predict_set[0][index][pixel_index] = string.atof(row[pixel_index])/255;<br />
index+=1;<br />
if index == predict_set_size: <br />
break;<br />
<br />
train_set = tuple(train_set);<br />
valid_set = tuple(valid_set);<br />
test_set = tuple(test_set);<br />
predict_set = tuple(predict_set);<br />
<br />
</syntaxhighlight><br />
<br />
===输出数据修改===<br />
theano的convnet是由两个卷积层,一个hidden layer和一个logistic regression构成的,如图<ref>http://deeplearning.net/tutorial/lenet.html</ref>:<br />
http://deeplearning.net/tutorial/_images/mylenet.png<br />
<br />
我们需要的是最后一层的输出,theano的样例程序在最后一层lr给了我们一个符号变量y_pred,定义如下:<br />
<syntaxhighlight lang="python"><br />
# initialize with 0 the weights W as a matrix of shape (n_in, n_out)<br />
self.W = theano.shared(value=numpy.zeros((n_in, n_out),<br />
dtype=theano.config.floatX),<br />
name='W', borrow=True)<br />
# initialize the baises b as a vector of n_out 0s<br />
self.b = theano.shared(value=numpy.zeros((n_out,),<br />
dtype=theano.config.floatX),<br />
name='b', borrow=True)<br />
<br />
# compute vector of class-membership probabilities in symbolic form<br />
self.p_y_given_x = T.nnet.softmax(T.dot(input, self.W) + self.b)<br />
<br />
# compute prediction as class whose probability is maximal in<br />
# symbolic form<br />
self.y_pred = T.argmax(self.p_y_given_x, axis=1)<br />
</syntaxhighlight><br />
<br />
手册上说可以使用eval()对其进行实例化<ref>http://deeplearning.net/software/theano/tutorial/adding.html#adding-two-scalars</ref>:<br />
<syntaxhighlight lang="python"><br />
predict_results = layer3.y_pred.eval({input:predict_set_x});<br />
</syntaxhighlight><br />
但是我这样做不行,只好用了很不理想的方案,原谅我<br />
<syntaxhighlight lang="python"><br />
predict_model = theano.function([index], layer3.predict(),<br />
givens={<br />
x: predict_set_x[index * batch_size: (index + 1) * batch_size]})<br />
</syntaxhighlight><br />
其中predict函数为:<br />
<syntaxhighlight lang="python"><br />
def predict(self):<br />
return T.mul(self.y_pred,1);<br />
</syntaxhighlight><br />
我对技术不敬畏,对不起各位了。<br />
<br />
这样我们就得到可以操作的数组,写入输出文件:<br />
<syntaxhighlight lang="python"><br />
predict_res_array = [predict_model(i) for i in xrange(n_predict_batches)]<br />
print predict_res_array;<br />
f = open("predict_res","w+");<br />
for y_pred_item_array in predict_res_array:<br />
for y_pred_item in y_pred_item_array:<br />
f.write(str(y_pred_item)+'\n');<br />
f.close();<br />
</syntaxhighlight><br />
<br />
===平移数据===<br />
以上可以差不多达到1.0%的误差,和理论值0.5%还有差距,我觉得可能是因为数据不够多,所以我对输入输出数据进行了平移预处理。<br />
输入数据平移:<br />
<syntaxhighlight lang="bash"><br />
#!/bin/bash<br />
awk -F , '{<br />
<br />
for (shiftx=-1;shiftx<=1;shiftx++) {<br />
for (shifty=-1;shifty<=1;shifty++) {<br />
<br />
printf $1","; <br />
<br />
for (y=0;y<28;y++) {<br />
for (x=1;x<=28;x++) {<br />
x_shift = x + shiftx;<br />
y_shift = y + shifty;<br />
if ((x_shift<1) || (x_shift>28) || (y_shift<0) || (y_shift>=28)) {<br />
printf "0,";<br />
} else {<br />
i=y_shift*28+x_shift+1;<br />
printf $i",";<br />
}<br />
}<br />
}<br />
<br />
printf"\n"<br />
<br />
}}<br />
//g' | sed 's/,$//g'<br />
</syntaxhighlight><br />
<br />
输出的时候让平移后的9个位置进行投票,boost了一把<br />
<syntaxhighlight lang="bash"><br />
#!/bin/bash<br />
awk '{<br />
dist[$0]++; <br />
if (NR%9==0) {<br />
best=1;<br />
for (x in dist) {<br />
if (dist[x]>dist[best]) best=x<br />
} <br />
printf best"\n"<br />
delete dist;<br />
}<br />
}'<br />
<br />
</syntaxhighlight><br />
<br />
ok,万事俱备,刷榜吧!<br />
<br />
==运行结果==<br />
[http://www.kaggle.com/c/digit-recognizer/leaderboard kaggle传送门]<br />
valid_set_error=0.90 test_set_error=0.68<br />
[[File:kaggle_mnist_rank1.png|800px]]<br />
<br />
[[File:kaggle_mnist_rank2.png|800px]]<br />
<br />
刷到前10,我感觉可以了,再往上刷10名就要被怀疑作弊了。<br />
<br />
==不明觉厉==<br />
simple cell到complex cell是怎么实现的?<br />
# 拿着某一斜率的filter去扫一遍全局的图像<br />
# 把图像分割成nxn份,做pooling(可以是max pooling)<br />
两个二维向量卷积的意思就是扫一遍,类似于你在暗处拿着一个手电筒把一篇文章看一遍。扫的每一帧的具体操作就是相乘(找相似的特征,仅仅是相乘就可以了)。卷积不是目的,扫一遍算相似度才是。<br />
<br />
当做polling的时候,时空信息就消失了,本来是28x28维的空间,如果4x4方块做pooling,就只剩下7x7的位置信息了。取而代之的,是feature域的信息。典型的“时空样本变换”,不过这个是98年就做出来的,实在是很赞。<br />
<br />
学习方案是构造一个损失函数,然后用SGD求解,因为有很多层,所以损失函数的梯度计算超级复杂,参数也很多很多,不过theano有一个库,可以自动计算梯度。先进行符号计算,然后Sample一些输入数据算梯度。<br />
<br />
嗯,大概就是这个样子吧。<br />
<br />
==改进==<br />
* 肖达说:“Hinton组的cuda-convnet GPU卷积库确实快,实现同样结构的卷积神经网做MNIST手写体分类,比theano的GPU卷积快5倍多。另一个发现,用sgd优化时,max kernel norm constraint比weight decay好用”。<br />
* cuda-convnet, https://code.google.com/p/cuda-convnet/<br />
* weight decay不知道theano用了没有<br />
<br />
==参考==<br />
<references/><br />
* pylearn2的convnet,http://nbviewer.ipython.org/urls/raw.github.com/lisa-lab/pylearn2/master/pylearn2/scripts/tutorials/convolutional_network.ipynb<br />
* theano是肖达告诉我的,GPU也是借用肖达的工作站的,非常感谢!<br />
* [[深度学习读书会]]<br />
* [[lwta-theano]]<br />
<br />
{{reply}}<br />
<br />
[[Category:统计学习读书会]] <br />
[[Category:集智俱乐部应用项目]]<br />
[[category:python]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%8A%95%E5%85%A5%E4%BA%A7%E5%87%BA%E6%B5%81%E7%BD%91%E7%BB%9C&diff=15161
投入产出流网络
2020-10-14T13:49:08Z
<p>Thingamabob:</p>
<hr />
<div>投入产出流网络<br />
<br />
==投入产出分析==<br />
<br />
===投入产出分析的具体方法及意义===<br />
投入产出分析(Input Output Analysis)是由著名经济学家Wassily Leontief提出的,用于量化经济系统中,各部门之间投入及产出相互依赖的关系。相关方法及理论,参见[[投入产出分析]]。<br />
<br />
在经济学研究中,投入产出分析方法可以解决产业结构分析、发展政策制定、经济状况预测等一些列热门的经济学问题。投入产出表刻画了各部门间价值的流动,并且将其数量化,提供了线性关系分析的基础框架。我们可以利用其计算中间投入系数、劳动投入系数、技术投入系数等一系列生产指性标,能构建一套完整的指标体系刻画社会经济的生产过程;与此同时投入产出表结合了国家的宏观数据,其中包括了消费、投资、进出口数据,使得我们在讨论生产的同时能够用刻画消费、投资、出口拉动经济增长的作用。并且投出产出将中间生产过程纳入整个核算体系,使得学者能够充分讨论部门间供求关系的相互影响,这是探讨产业结构的基础。<br />
<br />
<br />
===数据来源===<br />
<br />
投入产出表是经济分析中一种强有力的分析工具,因此各国、各地区都会进行投入产出数据的统计和核算工作,下面我们主要介绍一下中国、美国以及OECD组织发布的可得的投入产出表。<br />
<br />
====中国====<br />
每逢2和逢7的年份,中国国家统计局、国家发展和改革委员会、财政部会联合发文,布置并组织开展全国投入产出调查,编制投入产出基本表,目前中国官方编制的投入产出表共有6张,分别是1978年、1992年、1997年、2002年、2007年、2012年。每一年统计部门都会进一步的细化部门分类,因此每一年的部门数量不尽相同,越新的数据对应更细致的部门划分,更合理的核算数据衔接。相关数据都能够在中国投入产出协会官网中下载。(http://www.cioa.org.cn/)<br />
<br />
====美国====<br />
相对于中国提供的官方数据,美国商务部官方网站提供了美国自1947-2014年的投出产出表。同样的,美国的投入产出表不同年份的部门分类也有一定差异,并且采用不同的价格标准进行投入产出表的绘制,所有的数据都能在商务部网站中下载。(https://bea.gov/industry/io_annual.htm)<br />
<br />
====OECD====<br />
尽管各国都有官方都有投入产出的详细数据,但是它们存在一些问题:一是各国提供的投入产出表的年份不同;二是尽管能够克服年份不同的问题,各国核算编制过程中也采用了不同的产业分类。这两点会一定程度影响研究的可比性,为了克服这个问题,我们在研究过程中采用了OECD组织统一编制的投入产出表,该数据能够在OECD统计网站中下载。(http://stats.oecd.org/)<br />
<br />
OECD组织官方统计提供了1997-2012年,共计62个国家和地区34个产业之间的投入产出数据,具体见图片OECD国家编码以及OCED产业编码。<br />
<br />
[[File:国家编码.PNG|200px|thumb|OCED国家编码]]<br />
[[File:产业编码.PNG|200px|thumb|OECD产业编码]]<br />
<br />
====WIOD====<br />
OECD网站提供了各国分年份的国内投入产出系数表,而WIOD(World Input-Output Database)数据库再次基础之上提供了跨区域的投入产出数据,它包含了40个经济体35个产业之间的跨地区的投入产出数据,时间区间同样是1995年至2011年。其中有23个欧盟国家和13个其余经济体,其余经济体主要是东亚和北美的国家。跨区域数据的好处在于,不仅能够观察到各国国内投入产出的结构还能够探测跨国的、跨区域的投出产出状况,进一步将全球价值链量化。WIOD的产业分类同OECD的产业分类相同,国家数量相对OECD有所减少(见图WIOD国家)。值得注意的是,OECD和WIOD都提供了以区域计算的投入产出数据,主要的区域经济体是EU欧盟、NAFTA北美自由贸易区,EASTASIAN东亚。<br />
<br />
数据下载请转至WIOD官网[//http://www.wiod.org/new_site/database/wiots.htm]。<br />
<br />
==流动网络==<br />
<br />
===什么是流动网络===<br />
流动网络是用来表示某种事物的流动,根据系统中流量总量的变化,流动可以分为守恒流动和不守恒流动,分别对应平衡流网络和非平衡的流网络,更多流动网络的分析细节请参考[[流动网络]]。<br />
<br />
<br />
===为什么用流网络模型研究投入产出问题===<br />
前面提到投入产出分析能够帮助研究社会经济现象,包括产业结构、经济增长等一些列核心经济问题。但是值得注意的是,投入产出分析是基于线性计算的分析方法,能够刻画的是产业间、生产和消费间的线性关系,但是经济系统中很多相互影响并不是线性的,投入产出分析无法解释或者不能很好地解释社会经济系统中的非线性关系。介于社会经济系统本身就是一个巨大的复杂网络,所以将复杂网络分析和投入产出分析结合起来也是一个自然的想法。并且投入产出分析是基于一般均衡模型发展而来的研究方法,并且强调了实物流和价值流,这两个要点使得投入产出模型成为一个标准的开放型流网络。<br />
<br />
当然将复杂网络的思想运用到投入产出模型中并不是一件新奇的事情,传统的复杂网络分析也能够解决产业(部门)结构划分的问题,也能够个给出一系列中心度指标和网络指标,而运用流动网络的方法的优势在于,它能够从不同的角度回答投入产出系统中两个重要的问题:<br />
<br />
:一、如何定量地度量各产业之间投入产出的经济与技术联系?主流的分析方法延续了Hirschman(1958)提出的将前向/后向关联(FL/BL)效应的方法,最具有代表性的有中间投入率与中间产出率,影响力系数与感应度系数以及总关联系数、纯关联系数等(Cai和Leung,2004;Miller和Blair,2009)。这些指标通常是直接基于流量计算的,且只能反映产业间的一种联系,但是基于流量的方法虽然可以刻画出不同部门之间的直接或间接盈缺,却无法对不同国家的整体投入产出结构进行纵向比较,也无法对同一个国家不同时期的投入产出结构进行比较,这是因为所有的基于流量的指标都会受到国家经济总规模的影响,因此我们难以在不同的投入产出网之间进行有效的横向比较。<br />
:二、如何刻画国家的产业关联结构?一个可行的方案是引入图论与网络科学理论,例如Schnabl创立的最小流分析方法(Minimal Flow Analysis,MFA),Hioki、Hewings对中国地区产业结构的实证分析,Mcnemey,Fath和Silverberg对产业间流量结构的刻画等。但是传统的网络研究方法在探究近乎全连通的投入产出网的拓扑结构时捉襟见肘,人们不得不忽略连边方向性的考虑,甚至在破坏网络总体结构的情况下套用网络分析方法,这不仅难以全面地探究网络的拓扑性质,更难以综合考虑流量的影响。<br />
<br />
===如何建立投入产出的流网络===<br />
投入产出流网络的构建要基于投入产出表,一般的投入产出表(图3)纵向表示表示投入,横向表示产出,之前我们提到过,投入产出理论是基于一般均衡模型提出的,因此有总投入=总产出。根据国民生产总值(GDP)的定义,''GDP=Y<sub>1</sub>'',在这里投入产出表告诉我们GDP统计的生产总值只针对最终产品,而社会的总产出还要包括中间产品。注意,增加值是劳动者报酬、固定资产折旧、生产税净额以及营业盈余的总和,又可以成为最初投入。根据投入产出表能够推出如下等式成立(''N''为部门数):<br />
[[File:公式1.png]]<br />
<br />
[[File:投入产出表.png|500px|图3:投入产出表]]<br />
<br />
<br />
之前我们提到投入产出表反映了部门之间产品的流动,而产品的流动可以表示成两种形式,一种是实物的流动,一种是价值的流动,这两种流动的方向是相反的,这一点不难理解,假设部门1生产了产品1,最终产品1进入了部门2的生产线,那么对于产品1是从部门1流向部门2,同时部门2将与产品等价的资金付给部门1,因此资金流和实物流的流向是刚好相反的,理解这一点能够帮助我们构建投入产出的流动网络。通常来讲,投入产出表都是刻画的资金流,我们想要研究的系统是部门之间社会的生产系统,也就是中间产品转移的系统,因此最终产品的消费(最终需求)和初始产品的吸收(增加值)就是系统外的环境。开放型的流动网络保证系统和环境的连通需要设置两个节点,一个是源节点,一个是汇节点。源节点只允许事物流入,汇节点只允许事物流出。对于用资金流衡量的投入产出系统,流入系统的是最终消费形成的资金(重新注入生产部门),流出系统的是增加值,因此我们可以根据投入产出表建立如下流网络矩阵''F''(图4)注意这个''Z'' 矩阵是原投入产出表的转置矩阵。<br />
<br />
[[File:流矩阵.png|200px|图4:流矩阵]]<br />
<br />
==流距离的计算==<br />
流距离的相关计算方法及严格数学推导请参考[[基于马尔可夫链的流网络分析|基于马尔可夫链的流网络分析]]<br />
<br />
==结果展示==<br />
<br />
<br />
<br />
===产业流距离和流量的关系===<br />
[[File:D of VD new.png|500px|缩略图|居中|产业流距离和流量对比图]]<br />
上图展示了基于流量计算的流距离大小与流量大小的关系,横坐标是产业间资金流量的对数大小,纵坐标是流距离的长短。整体上,流距离大小和流量的多少呈负相关,产业间流量越大,产业间的流距离越小,意味着一定程度上,流距离吸收了产业间流量的信息,能够一定程度上反应产业间资金来往的密集程度。但是,流距离和流量是完全两种不同的指标,流距离除了考虑流量因素外,还考虑了网络中两个节点之间的拓扑关系。<br />
<br />
图中我们发现有些产业之间的资金往来很小,但是流距离却比一些流量更大的产业对的流距离更小,比如中国的金融业和木制品制造业,美国的水电气供应业和木制品制造业,他们几乎是产业间资金流最小的产业对,但是流距离却不是大的。这说明这两个产业对之间的联系很紧密,但并不是靠流量信息体现的,而是拓扑结构。它们之间存在很短的路径。这再次说明流距离包含信息的丰富性和可对比性。<br />
<br />
<br />
<br />
===中美两国产业结构对比===<br />
下图是2011年中美两国的产业结构图,右图中节点代表产业,节点大小正比于该产业的总产出;节点的颜色代表产业的分类,共五类;横坐标表示产业的从源距离,纵坐标代表产业到汇距离,为了方便比较产业两类特征距离的大小,我们添加了y=x的蓝色辅助线;我们用平均从源距离和平均到汇距离,即竖直灰色辅助线和水平灰色辅助线,把产业结构图分为A、B、C、D四个区域,方便以后的讨论。在右侧产业结构图中,有些产业位置相近重叠在了一起,为了更好的体现他们的相对位置,我们在左侧小图中放大了这些重叠在一起的产业节点。<br />
[[File:SS USA new1.png|500px|framed|居中|美国源汇图]]<br />
[[File:SS CHN new1.png|500px|framed|居中|中国源汇图]]<br />
<br />
从源距离和倒汇距离反映的是产业与最终需求与增加值的靠近程度,这种靠近既可以是由相互作用的强度(权重信息)引起的,也可以是由生产链上下游关系(拓扑连边)决定的。<br />
# 从源距离小,一方面可能是产业最终需求大,或者说产业的创造的国内生产总值高;另一方面可能是因为产业离投资、消费市场更接近,消费、投资的资金流更倾向于直接进入这些产业。<br />
# 到汇距离小,一方面可能是产业创造的增加值高。另一方面从与货币流对偶的商品流看来,一个产业到货币流的汇靠近就是产业距离商品流的源越靠近,所以该产业越依赖于原始生产材料。<br />
<br />
从图中看:<br />
* C区域的产业拥有较小的从源距离和到汇距离,该区域主要包含大部分盈利性服务业和非盈利性的服务业,比如健康医疗、教育行业等,这些产业创造的增加值高,拥有加大的最终需求,并且直接面向消费着,消费者会直接购买这些企业提供的服务。<br />
*与C区域刚好相反,B区域中产业的两类特征距离比较大,主要以基础工业和部分重工业为主。这些产业创造的增加值低,创在的GDP相对较低,并且距离消费市场很远,产业生产的产品通常会作为其他产业的中间投入,不太可能被消费者直接购买。<br />
*加工制造业主要集中在A区域,从源距离小,到汇距离大。通常是一些劳动密集型的产业,比如纺织业、汽车及相关制造业。这些产业创造的附加值不高,吸收的最终需求也不高,但是这些产业生产的产品通常是一些生活必需品,比如服装、食品,它们天生靠近消费市场,因此从源距离小。<br />
*D区域则主要包含了部分商业服务业,比如运输业,同大多数服务业一样,这些产业创造的增加值高,到汇距离小;但相比其他服务业离消费者更远,比如研发业,消费者不太可能直接消费该产业的服务。在这个区域,会有一些资源型的产业,比如采矿业和炼油业,它们之所以拥有较小的到汇距离是因为它们是依赖于生产材料的。<br />
<br />
中美不同的是:<br />
#整体上看,美国两类特征距离的均值都小于中国,意味着整体上美国生产系统的运转更有效,一方面流量上,美国生产系统创造的国内生产总值和增加值到高于中国(2011年美国GDP十万亿级,中国GDP万亿级);另一方面产业链上下游的关系更紧密。<br />
#中美有很多产业在整体结构中拥有完全不同的生态位,比如计算机及电子设备制造业(CompE),中国的计算机相关制造业处于A区域,而美国处D区域,中国该产业增加值占生产总值的比例远小于美国,这象征在该产业的全球价值价值链中中美完全不同的地位。中国只是一个加工者,在产业的生产过程中贡献的价值极低;反观美国,是一个研发者、创造者,有着巨大的技术优势,掌握了大部分的收益。<br />
<br />
<br />
<br />
<br />
===从整体产业变迁挖掘特殊产业演化===<br />
我们利用特征距离,不仅可以实现不同国家产业结构的对比,还可以利用时间序列数据,刻画一国产业结构的变迁轨迹,并以此为对照,发现与整体演化趋势相异的产业,进而观察这些特殊产业的演化特征。上图是中国房地产业与整个生产系统演化轨迹的对比图,我们删掉了一些年份的数据,使得两者的演化趋势更平滑;横坐标是从源距离,纵坐标是到汇距离,左图是房地产业的演化轨迹,右图是将33个产业抽象为一个整体的生产系统,用它们的平均从源距离和到平均汇距离作为特征距离表示的生产系统整体的变迁轨迹。<br />
<br />
[[File:Evo of real CHN new.png|500px|缩略图|居中|中国房地产业的演化]]<br />
<br />
从图中我们发现,房地产业的演化轨迹与整体生产系统的变迁轨迹大不相同,也就说明在中国产业结构的演化中,房地产业是一个极为特殊的产业,有别于大部分产业的发展。从图中看<br />
中国房地产业主要经历了3个阶段:<br />
{| class="wikitable"<br />
|-<br />
! 演化阶段 !! 主要趋势 !! 相关事件<br />
|-<br />
| 1995-2005年 || 从源距离大幅度的增加,吸引了大量的投资消费,产业发展迅发展;到汇距离在逐渐增大,增加值创造速率比不上资金流入速率,形成市场泡沫。 || 邓小平南巡之后,南方掀起了一股炒房风波;2000之后,福利分房制度被货币分房制度所替代,刺激了商品房的市场化。<br />
|-<br />
| 2005-2007年 || 从源距离有小幅度增加,资金进入房地产业的流量和速率在减缓;倒汇距离大幅度减小,创造增加值的能力有所回升。 || 2005年之后新旧《国八条》的颁布,从价格、税收、信息监管和供应结构等多方面调整了房地业的产品结构,增加了普通商品房和经济适用房的供应,同时持续的加息与紧缩的信贷政策,限制了非理性炒房资金的进入。<br />
|-<br />
| 2007-2011年 || 从源距离几乎不变,房地产业资金流入量被严格控制;到汇距离的增加,商品房成交量的下降,房地业营业额减低,创造的增加值降低。 || 2007年后中国实行了全面的宏观政策调控,持续紧缩的信贷政策控制了房价的升温,加上2008年收到全球性金融危机的影响,房产市场受冷。<br />
|}<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E5%88%86%E6%9E%90%E5%8F%A5%E6%B3%95%E7%9A%84%E7%BB%93%E6%9E%84&diff=15160
分析句法的结构
2020-10-14T13:48:18Z
<p>Thingamabob:创建页面,内容为“==句子的构成== 对于使用比较短句子的文本,使用n-gram token(n个词构成的部分)的词频等统计信息就可以描述文本的特征。但对…”</p>
<hr />
<div>==句子的构成==<br />
<br />
对于使用比较短句子的文本,使用n-gram token(n个词构成的部分)的词频等统计信息就可以描述文本的特征。但对于较长句子,我们需要分析句法的结构和词的词性来进行更精确的分析。例如,下面是一张词性对照表:<br />
<br />
Symbol Meaning Example<br />
S sentence the man walked<br />
NP noun phrase a dog<br />
VP verb phrase saw a park<br />
PP prepositional phrase with a telescope<br />
Det determiner the<br />
N noun dog<br />
V verb walked<br />
P preposition in<br />
<br />
==语法分析及其可视化==<br />
<br />
为了把句子拆开,展示句子的结构,我们可以使用nltk包如下<br />
<syntaxhighlight lang="python"><br />
import nltk<br />
<br />
grammar1 = nltk.parse_cfg("""<br />
S -> NP VP<br />
VP -> V NP | V NP PP<br />
PP -> P NP<br />
V -> "saw" | "ate" | "walked"<br />
NP -> "John" | "Mary" | "Bob" | Det N | Det N PP<br />
Det -> "a" | "an" | "the" | "my"<br />
N -> "man" | "dog" | "cat" | "telescope" | "park"<br />
P -> "in" | "on" | "by" | "with"<br />
""")<br />
<br />
sent = "the man saw Bob with the telescope".split()<br />
<br />
rd_parser = nltk.RecursiveDescentParser(grammar1)<br />
<br />
for tree in rd_parser.nbest_parse(sent):<br />
print tree<br />
<br />
tree1 = nltk.Tree('S', [nltk.Tree('NP', [nltk.Tree('Det', ['the']), <br />
nltk.Tree('N', ['man'])]), nltk.Tree('VP', [nltk.Tree('V', ['saw']), <br />
nltk.Tree('NP', ['Bob']), nltk.Tree('PP', [nltk.Tree('P', ['with']), <br />
nltk.Tree('NP', [nltk.Tree('Det', ['the']), nltk.Tree('N', ['telescope'])])])])])<br />
<br />
tree1.draw()<br />
</syntaxhighlight><br />
<br />
最后可以得到这张图<br />
<br />
[[File:grammar_tree_1.png|500px]]<br />
[[Category:旧词条迁移]]</div>
Thingamabob
https://wiki.swarma.org/index.php?title=%E6%8A%95%E5%85%A5%E4%BA%A7%E5%87%BA%E6%B5%81%E7%BD%91%E7%BB%9C&diff=15159
投入产出流网络
2020-10-14T13:47:35Z
<p>Thingamabob:清空页面</p>
<hr />
<div></div>
Thingamabob