复杂文摘翻译第一期-2016.07

Complex Digest 复杂文摘翻译第一期-(摘自Complex Digest 2016.6月文章)

人之初,性本善?(Selfishness Is Learned)

By Matthew Huston, Illustration by Francesco Izzo

导读(by 傅渥成)

在东方和西方都一直存在着“性善”和“性恶”的争论,同为儒家代表人物的孟子和荀子既有不同的看法;而在西方,卢梭和霍布斯同样有着截然不同的看法。亚当·斯密在他《道德情操论》中指出人天生会关心别人的命运,具备同情心或怜悯心;而他又在其《国富论》中最早提出了“经济人”的想法:“我们每天所需要的食物和饮料,不是出自屠户、酿酒家和面包师的恩惠,而是出于他们自利的打算。”他认为人类行为动机的根源来自于经济诱因,而我们每个人都在不断追求最大的经济利益。现在,“经济人”现在已经成为了经济学和某些心理学分析的一个重要的基本假设,这一假设可以帮助我们简化许多复杂的经济学问题,但当我们在这一框架下来思考问题时,我们却反而难以理解道德的产生,例如我们很容易理解一些人的逃税行为,但我们无法理解一些人明知逃税也不会被抓、可仍然坚持纳税的行为。

事实上,当我们在讨论“性善”或”性恶“时,需要区分的是人类的“理性”和真正的“本性”。这让我们想到了丹尼尔·卡尼曼的《思考,快与慢》,卡尼曼将人类的行为决策分成两个系统,其中系统 1 负责毫不费力的直觉性的思考,而系统 2 则需要费力的自我控制。借鉴这一观点,我们会想到的是,如果想要有说服力地证明“性善”或”性恶“,那么只证明系统 2 的自私本性其实并没有什么作用,我们想要知道的其实是当我们进行毫不费力的直觉性的思考时,到底是倾向于变得自私还是利他。事实上,早在 2012 年,就有实验结果表明,当一个人越快做出决定时,他就越倾向于无私地“给予”,而一个深思熟虑的人则越倾向于“自私”。这也与我们的生活经验很符合,许许多多见义勇为的英雄在事后回顾其救人的经历时也会说自己并没有考虑太多就已选择为他人赴汤蹈火。这个结论某种意义上暗示我们,人类的确“人之初,性本善”,倾向于在博弈中采取合作行为,尤其是当人类在进行一些快速的决定时;然而人类在理性的思考中习得了自私,这才导致了博弈中背叛行为的出现。Matthew Huston 的这篇通俗易懂的文章( http://nautil.us/issue/37/currents/selfishness-is-learned )对与此有关的许多模型和实验进行了详细的回顾,推荐各位有兴趣的朋友进行阅读。

这篇文章主要介绍的一个近期工作来自于这篇论文:

Intuition, deliberation, and the evolution of cooperation

Humans often cooperate with strangers, despite the costs involved. A long tradition of theoretical modeling has sought ultimate evolutionary explanations for this seemingly altruistic behavior. More recently, an entirely separate body of experimental work has begun to investigate cooperation’s proximate cognitive underpinnings using a dual-process framework: Is deliberative self-control necessary to reign in selfish impulses, or does self-interested deliberation restrain an intuitive desire to cooperate? Integrating these ultimate and proximate approaches, we introduce dual-process cognition into a formal game-theoretic model of the evolution of cooperation. Agents play prisoner’s dilemma games, some of which are one-shot and others of which involve reciprocity. They can either respond by using a generalized intuition, which is not sensitive to whether the game is one-shot or reciprocal, or pay a (stochastically varying) cost to deliberate and tailor their strategy to the type of game they are facing. We find that, depending on the level of reciprocity and assortment, selection favors one of two strategies: intuitive defectors who never deliberate, or dual-process agents who intuitively cooperate but sometimes use deliberation to defect in one-shot games. Critically, selection never favors agents who use deliberation to override selfish impulses: Deliberation only serves to undermine cooperation with strangers. Thus, by introducing a formal theoretical framework for exploring cooperation through a dual-process lens, we provide a clear answer regarding the role of deliberation in cooperation based on evolutionary modeling, help to organize a growing body of sometimes-conflicting empirical results, and shed light on the nature of human cognition and social decision making.


直觉与刻意——合作行为的进化

何以人们常与陌生人不计成本地合作?长久以来,人们进行了大量的理论模拟,试图找到这种近似「无私」的行为在进化中出现的根本原因。然而,最近有大量的实验工作另起炉灶,开始研究合作行为在认知学上的直接原因。这些新近实验研究的框架可以精炼为「双重认知」的过程:或是有意识地自控、合作,并试图驾驭自私自利的冲动;或是有意识地自私自利,并以此限制合作的本能。

本文中,我们将上述对根本、直接两方面原因的探索结合起来,在合作行为进化的博弈论模型中,引入双重认知的过程。在这个博弈模型中,行动者将参与一次性的或多次性的「囚徒困境」博弈,后一类博弈涉及互惠与合作。此时行动者将有两种响应的方式:他们可以无视一次性与多次性博弈的差别,一律按通用的直觉行事;也可以付出一些随机的代价,进而刻意地针对不同类型博弈调整其行事策略。

我们发现,依互惠程度与策略搭配的不同,自然选择将对下列两种策略之一有利:要么不论博弈的种类,发自本能地背叛对方;要么具备一定的「双重性格」,一方面本能地与对方合作,另一方面在一次性博弈中刻意地背叛对方。这里的关键之处在于,有意识地克制自私自利冲动的行动者从不会在自然选择占据有利地位。也就是说,「刻意」在进化中的唯一目的就是破坏与陌生人的合作。

总言之,本文在一套规范的理论框架下,从「双重认知过程」的角度研究合作行为,明确了「刻意」在合作行为的进化过程中扮演的角色。我们的结果不仅将有助于整合近来出现的大量实验结果,还将有助于理解人类认知与社会决策的本质。

原文链接:http://www.pnas.org/content/113/4/936.full

政府“敦促”,确有价值(Government ‘nudges’ prove their worth )

John Bohannon

(Translated by 王硕-)


Over the past 5 years, on behalf of state governments, nearly 100,000 Americans were gently manipulated by a team of social scientists. In 15 randomized, controlled trials, people in need of social services either encountered the standard application process or received a psychological nudge, in which the information was presented slightly differently—a postcard reminded them of deadlines, for example, or one choice was made easier than another. In 11 of the trials, the nudge modestly increased a person's response rate or influenced them to make financially smarter choices. The results, presented this week at a meeting in Chicago, add to the growing evidence that nudges developed by psychologists can make a real difference in the success of government programs.

过去五年中,近100,000美国人被一个受雇于政府的社会科学家团队轻轻地操控着。在15个随机对照实验中,需要社会服务的人们或采取标准申请过程或受到心理学上的“敦促”,他们传递出的信息稍有不同。例如用一张明信片提醒他们截止日期,让作某个选择变得更加容易。其中的11个实验中,这种“敦促”一定程度上提高了人的反应速度,或者使他们做出了更为明智的经济选择。上周在芝加哥召开的会议上公布了这一结果,进一步证明了心理学家的“敦促”有助于提高政府项目的成功率。

原文链接:http://science.sciencemag.org/content/352/6289/104

译文建议:

1. “nudges”:翻译成“推动”没有错,但读者可能难以领会其所指,建议用意义更明确的“助推”、“敦促”或“提醒。”

2. “a team of social scientists”,“on behalf of state governments”:这是代表政府或受雇于政府的一个社会学家团队,有明确所指。

3. “gently manipulated”:应该是指的软性的非强制性的提醒和操控。

4. “one choice was made easier than another”:让作某个选择变得更容易。

译文建议已经采纳。

数字时代的匹配市场(Matching markets in the digital age)

Eduardo M. Azevedo1, E. Glen Weyl2,3

(Translated by Cicely)

Recent advances in information technology are enabling new markets and revolutionizing many existing markets. For example, taxicabs used to find passengers through chance drive-bys or slow central dispatching (see the photo). Location tracking, computer navigation, and dynamic pricing now enable ride-sharing services such as Uber to offer low and consistent delay times of only a few minutes. In a recent study, Cramer and Krueger (1) show that ride-sharing has dramatically increased the usage of drivers and their cars, cutting costs for riders. The results highlight the opportunities provided by digital markets. Further efficiency gains may come from academia-industry collaborations, which could also help to ensure that the markets develop in ways that further the public interest.


近年来,信息技术的发展不仅使得新兴市场得以开发,也使得传统市场发生变革。例如,传统出租车行业通过随机的“招手即停”或缓慢的中心调度的方式揽客。而以Uber为代表提供的拼车服务运用到定位跟踪、计算机导航以及动态定价等技术,仅存在几分钟的稳定延迟时间。来自Cramer及Krueger的最新研究显示,拼车服务的出现难以想象地提高了司机对于汽车的利用度,同时降低了乘客的出行成本。这一结果充分突显了数字市场带来的机遇。未来,学术产业间合作将更进一步提升效益,同时也可确保市场向大众感兴趣的方向发展。

原文链接:http://science.sciencemag.org/content/352/6289/1056

面向在线社交网络的一种标准采样方法:采集Twitter上的全球趋势(Towards a standard sampling methodology on online social networks: collecting global trends on Twitter)

C. A. Piña-GarcíaEmail author, Carlos Gershenson and J. Mario Siqueiros-García

(Translated by 一 卢罡)

One of the most significant current challenges in large-scale online social networks, is to establish a concise and coherent method aimed to collect and summarize data. Sampling the content of an Online Social Network (OSN) plays an important role as a knowledge discovery tool.

当前大规模在线社交网络相关研究中最重大的挑战之一,就是建立一个简洁明了的方法来收集和概括数据。作为知识发现的一种工具,在线社交网络内容的采样在这方面发挥了重要作用。

It is becoming increasingly difficult to ignore the fact that current sampling methods must cope with a lack of a full sampling frame i.e., there is an imposed condition determined by a limited data access. In addition, another key aspect to take into account is the huge amount of data generated by users of social networking services such as Twitter, which is perhaps the most influential microblogging service producing approximately 500 million tweets per day. In this context, due to the size of Twitter, which is problematic to be measured, the analysis of the entire network is infeasible and sampling is unavoidable.

目前的采样方法缺少一个完整的采样框架,这是越来越不容忽视的,比如有限的数据访问权限就给这项工作带来了巨大的限制。另一个关键问题,是社交网络服务中用户产生的数据量非常庞大。例如Twitter上每天会产生大约5亿条推文,可能是世界上影响力最大的微博服务了。在这种情况下,Twitter过于庞大以至无法度量,导致对其整个社交网络的分析往往不切实际,从而采样成了不可或缺的手段。

In addition, we strongly believe that there is a clear need to develop a new methodology to collect information on social networks (social mining). In this regard, we think that this paper introduces a set of random strategies that could be considered as a reliable alternative to gather global trends on Twitter. It is important to note that this research pretends to show some initial ideas in how convenient are random walks to extract information or global trends.

另外,我们坚信人们对于开发一个新的方法来收集社交网络中的信息(社会挖掘)有着明确的需求。本文介绍了一系列的随机策略,它们能够作为收集Twitter上的全球趋势的可靠备选方案。值得注意的是,这项研究声称展示了一些将随机游走方便地用于抽取信息或全球趋势上的初步设想。

The main purpose of this study, is to propose a suitable methodology to carry out an efficient collecting process via three random strategies: Brownian, Illusion and Reservoir. These random strategies will be applied through a Metropolis-Hastings Random Walk (MHRW). We show that interesting insights can be obtained by sampling emerging global trends on Twitter. The study also offers some important insights providing descriptive statistics and graphical description from the preliminary experiments.

这项研究的主要目的,是提出一个新的方法,该方法通过将布朗随机、幻象随机和蓄水池随机3种随机策略应用于Metropolis-Hastings随机游走(MHRW)过程,实现了高效的数据采集。通过对Twitter上正在形成的全球趋势进行采样,我们展示了一些有趣的见解。通过描述性统计和图形化描述,初步的实验结果还揭示了一些重要的结论。

原文链接:http://link.springer.com/article/10.1007/s41109-016-0004-1

译文建议:

1.标题的“toward”:可以为“面向”或“针对。”

欧洲议会的推特转发网络:社团结构评估 Retweet networks of the European Parliament: evaluation of the community structure

Cherepnalkoski and Mozetič

(Translated by 阎赫)

欧洲议会的推特转发网络:社团结构评估

Analyzing information from social media to uncover underlying real-world phenomena is becoming widespread. The goal of this paper is to evaluate the role of Twitter in identifying communities of influence when the ‘ground truth’ is known. We consider the European Parliament (EP) Twitter users during a period of one year, in which they posted over 560,000 tweets. We represent the influence on Twitter by the number of retweets users get. We construct two networks of influence: (i) core, where both users are the EP members, and (ii) extended, where one user can be outside the EP. We compare the detected communities in both networks to the ‘ground truth’: the political group, country, and language of the EP members. The results show that the core network closely matches the political groups, while the extended network best reflects the country of origin. This provides empirical evidence that the formation of retweet networks and community detection are appropriate tools to reveal real-world relationships, and can be used to uncover hidden properties when the ‘ground truth’ is not known.

摘要:通过分析来自媒体社交的信息以揭示隐含的真相已越来越普遍。本论文的目的是在已知实际情况下,评估推特在识别影响力共同体中的作用。在一年内我们以欧洲议会中的推特用户们为研究对象,期间他们共发帖五十六万条。我们以这些推特使用者所得到的转帖数量代表其影响力,构建了两个影响力网络(i)核心网络,发帖转帖用户都是EP成员,(ii)扩展网络,至少有一个用户可以不是EP。我们将两种网络中识别出的群体与实际情况进行比对,包括EP成员的政治群体,所属国家和语言。结果显示核心网络和政治群体匹配密切,而扩展网络则最能反映这些议会成员的祖国。这为我们提供了实验证明,即推特转发网络的结构和社团发现算法是揭示与现实世界关联的适当工具,并且可以在不知道实际数据时还能揭示隐含的特性。

原文链接: http://appliednetsci.springeropen.com/articles/10.1007/s41109-016-0001-4

译文建议:

1. “retweet” 直接译成“推特转发”或“转发”就可以,“锐推”不好理解。

2.“communities of influence”:不是“社团影响力”,应为“影响力社群”或“影响力共同体”:

3.“ground truth”:可以译成“实际情况。”

4. “social media”:“社交媒体”

5. “We consider”:“以...为研究对象”

6.“代表其在社团中的影响力”:原文没有“在社团中的。”

7.“We construct two networks of influence”:译成“由此构建了两个基于转贴的影响力网络”与原文差异过大。

8.“where both users are the EP members”:译成“用户都是EP成员”即可。“where one user can be outside the EP”:“至少有一个用户可以不是EP。”

9.“compare the detected communities in both networks to the ‘ground truth’”:“将两个网络中识别出的社群(共同体)与‘实际情况’进行对比。”

10. “real-world relationships”:“现实世界的关联”

当人脸跟踪遭遇社交网络:新闻视频中的政治故事 When face-tracking meets social networks: a story of politics in news videos

Benjamin Renoust

(Translated by 张皓-人机与环境工程-南京)


In the age of data processing, news videos are rich mines of information. After all, the news are essentially created to convey information to the public. But can we go beyond what is directly presented to us and see a wider picture?

在数据处理的时代,新闻视频是一座信息的富矿。毕竟,新闻本质上就是为了向公众传递信息。然而我们是否可以超越这些直接向我们呈现的内容从而看到一个更为广阔的信息图景?

Many works already focus on what we can discover and understand from the analysis of years of news broadcasting. These analysis bring monitoring and understanding of the activity of public figures, political strategies, explanation and even prediction of critical media events. Such tools can help public figures in managing their public image, as well as support the work of journalists, social scientists and other media experts.

许多的工作已经聚焦于对多年新闻播报的分析所得到的发现与理解。这些分析能帮助监测和理解公众人物的活动、政治策略,解释甚至预测重大媒体事件。帮助公众人物管理他们的公众形象,也同样能辅助新闻从业者、社会科学家以及媒体专家的工作。

News analysis can also be seen from the lens of complex systems, gathering many types of entities, attributes and interactions over time. As many public figures intervene in different news stories, a first interesting task is to observe the social interactions between these actors. Towards this goal, we propose to use video analysis to automatise the process of constructing social networks directly from news video archives. In this paper we are introducing a system deriving multiple social networks from face detections in news videos. We present preliminary results obtained from analysis of these networks, by monitoring the activity of more than a hundred public figures. We finally use these networks as a support for political studies and we provide an overview of the political landscape presented by the Japanese public broadcaster NHK over a decade of the 7 PM news archives.

在聚集了大量的实体类别、属性以及随时交互的情况下,新闻分析同样可以从复杂系统的角度考量。由于大量的公众人物会在不同的新闻事件中相互交集,第一个有趣的研究就是观察这些人物之间相互的社交往来。为了完成这个目标,我们建议通过视频分析直接研究新闻视频存档来自动构建这些公众人物的社交网络。在这篇文章中,我们引入一个可以通过对新闻视频进行面部识别来构建多层社交网络的系统。通过对这些社交网络的分析,我们对一百多名公众人物的行为进行了跟踪,获得了一个初步的结果。最终,我们将这些社交网络用于政治研究,并基于日本公共传播机构NHK十年存档的晚上7点新闻,我们提供了一个政治图景的综述。

原文链接:http://appliednetsci.springeropen.com/articles/10.1007/s41109-016-0003-2

全局优化、局部适应和生长在分配网络中的作用(Global optimization, local adaptation and the role of growth in distribution networks)

Henrik Ronellenfitsch, Eleni Katifori

(Translated by 苏格兰)


Highly-optimized complex transport networks serve crucial functions in many man-made and natural systems such as power grids and plant or animal vasculature. Often, the relevant optimization functional is non-convex and characterized by many local extrema. In general, finding the global, or nearly global optimum is difficult. In biological systems, it is believed that natural selection slowly guides the network towards an optimized state. However, general coarse grained models for flow networks with local positive feedback rules for the vessel conductivity typically get trapped in low efficiency, local minima. In this work we show how the growth of the underlying tissue, coupled to the dynamical equations for network development, can drive the system to a dramatically improved optimal state. This general model provides a surprisingly simple explanation for the appearance of highly optimized transport networks in biology such as leaf and animal vasculature.

摘要:高度优化的复杂传输网络在诸如电网、发电厂或动物血管等人造系统或自然系统中发挥着至关重要的作用。相关优化函数非凸,并以许多局部极值为特征,一般情况下很难找到全局优化或近似全局优化。通常认为,在生物系统中,自然选择缓慢地引领该(传输)网络趋向于最佳状态。然而,带有局部正反馈规则的广义流体网络粗粒度模型却常常囿于低效率的局部极小值。本研究解释了与网络发展动力学方程相耦合的深层组织生长如何使整个系统得到显著改善,并达到最优状态。在植物叶子和动物血管中呈现出高度优化的传输网络,该广义模型为此提供了一个极其简单的解释。

原文链接:http://arxiv.org/pdf/1606.00331.pdf

译文建议:

1.“相关优化功能通常是非凸的”:应该是“函数非凸。”

2.“it is believed”:“通常认为”

社会困境的生态进化动力 (Eco-evolutionary dynamics of social dilemmas)

Chaitanya S. Gokhale, Christoph Hauert

(To be translated by 晓雷)


Social dilemmas are an integral part of social interactions. Cooperative actions, ranging from secreting extra-cellular products in microbial populations to donating blood in humans, are costly to the actor and hence create an incentive to shirk and avoid the costs. Nevertheless, cooperation is ubiquitous in nature. Both costs and benefits often depend non-linearly on the number and types of individuals involved -- as captured by idioms such as `too many cooks spoil the broth' where additional contributions are discounted, or `two heads are better than one' where cooperators synergistically enhance the group benefit. Interaction group sizes may depend on the size of the population and hence on ecological processes. This results in feedback mechanisms between ecological and evolutionary processes, which jointly affect and determine the evolutionary trajectory. Only recently combined eco-evolutionary processes became experimentally tractable in microbial social dilemmas. Here we analyse the evolutionary dynamics of non-linear social dilemmas in settings where the population fluctuates in size and the environment changes over time. In particular, cooperation is often supported and maintained at high densities through ecological fluctuations. Moreover, we find that the combination of the two processes routinely reveals highly complex dynamics, which suggests common occurrence in nature.


社会困境是社会互动的重要组成部分。从微生物种群分泌胞外产物到人类的献血行为都是一种合作行为,合作行为的参与者要付出高昂的代价,因此出现了一种激励机制来避免损失。然而,合作行为在自然界却是普遍存在的。利弊通常与参与个体的数量和种类有着非线性的关系 - 正如一些习语所表达的意思那样,“人多反误事”表明多余的贡献反而会打折扣,“人多力量大”表明合作行为使得组织更加获益。交互组的大小可能取决于群体大小以及其伴随的生态过程。这在生态环境和进化过程(两者共同影响和决定了进化轨迹)之间产生了一种反馈机制。 也仅仅是在最近,两者组合在一起的生态进化过程才在微生物社会困境中变得易于实验处理。本文将通过设定群体的大小不断波动和环境不断改变来分析非线性社会困境的进化动力。尤其是合作行为总是通过生态波动被保持和维护在很高的密度。而且我们发现两种过程的组合也揭示了高度复杂的动力,这暗示了这一现象在自然界是普遍存在的。

原文链接:http://arxiv.org/abs/1605.07656

交易网络及信用因素的建模(Modelling Trading Networks and the Role of Trust)

Rafael A. Barrio, Tzipe Govezensky, Élfego Ruiz-Gutiérrez, Kimmo K. Kaski

(Translated by jeffersonchou)

We present a simple dynamical model for describing trading interactions between agents in a social network by considering only two dynamical variables, namely money and goods or services, that are assumed conserved over the whole time span of the agents' trading transactions. A key feature of the model is that agent-to-agent transactions are governed by the price in units of money per goods, which is dynamically changing, and by a trust variable, which is related to the trading history of each agent. All agents are able to sell or buy, and the decision to do either has to do with the level of trust the buyer has in the seller, the price of the goods and the amount of money and goods at the disposal of the buyer. Here we show the results of extensive numerical calculations under various initial conditions in a random network of agents and compare the results with the available related data. In most cases the agreement between the model results and real data turns out to be fairly good, which allow us to draw some general conclusions as how different trading strategies could affect the distribution of wealth in different kinds of societies.

本文提出了一个简化的、用以描述社会关系网络中,行为主体间交易互动行为的动态模型;这个模型只考虑代表金钱和商品或服务的两个动态变量,并假设在行为主体交易的时间段内,这两个变量(的累加和)保持不变。这个模型的关键点是:行为主体之间的交易互动由商品或服务的单价所支配,而单价则会根据行为主体的信用度动态变化,行为主体的信用度与其交易历史(所产生的声望)相关。每个行为主体都可以进行买卖,成交与否,既取决于卖家眼中买家的信用度,也取决于商品单价以及买家需要为商品支付的金钱总量。论文中,我们提供了大量的此模型在同一行为主体随机网络中,不同初始条件下量化计算的结果,并将此结果与现实世界中可找到的类似数据进行了比较。在大多数情况下,本模型的计算结果与(现实世界的)真实数据相当契合,这就让我们能对代理人的交易策略,如何影响不同类型社会的财富分布,得出一些普适性的结论。

原文链接http://arxiv.org/abs/1605.08899

全球网络财团的中心性(Centrality in the Global Network of Corporate Control)

Frank W. Takes, Eelke M. Heemskerk

(Translated by Weisi Yang)


Corporations across the world are highly interconnected in a large global network of corporate control. This paper investigates the global board interlock network, covering 400,000 firms linked through 1,700,000 edges representing shared directors between these firms. The main focus is on the concept of centrality, which is used to investigate the embeddedness of firms from a particular country within the global network.

全世界的公司被规模巨大的全球财团网络高度控制。这篇文章研究了全球董事会连锁网络,这一网络覆盖了由1,700,000优势代表公司间共同执行者的400,000公司.主要的研究重点在于中心性的概念,这一概念被用来研究处于全球网络结构中一个典型国家的公司的嵌入性。

The study results in three contributions.

本研究取得3个突破。

First, to the best of our knowledge for the first time we can investigate the topology as well as the concept of centrality in corporate networks at a global scale, allowing for the largest cross-country comparison ever done in interlocking directorates literature. We demonstrate, amongst other things, extremely similar network topologies, yet large differences between countries when it comes to the relation between economic prominence indicators and firm centrality. Second, we introduce two new metrics that are specifically suitable for comparing the centrality ranking of a partition to that of the full network. Using the notion of centrality persistence we propose to measure the persistence of a partition's centrality ranking in the full network. In the board interlock network, it allows us to assess the extent to which the footprint of a national network is still present within the global network.

首先,第一次竭尽我们所知来研究拓扑学和在全球范围内公司网络中的中心性概念,同时顾及了在连锁董事会资料中规模最大的跨国比较。我们发现,除去其它因素,极其相似的网络拓扑中,国家间最大的差异在于经济主导因子和公司中心性。第二,我们引入两个新的矩阵,它们适用于比较一个分区内完整的网络中心地位级别。通过引入中心性持久度概念,我们计划评估一个分区在整个网络内中心性级别的持久度。它使我们能够评估到其中的一个全国性的网络足迹是全球网络范围内仍然存在的程度。 ''Next, the measure of centrality ranking dominance tells us whether a partition (country) is more dominant at the top or the bottom of the centrality ranking of the full (global) network.'' <nowiki>评估中心性等级优势能够说明一个分区处于在整体网络中心性等级地位的高低水平。

Finally, comparing these two new measures of persistence and dominance between different countries allows us to classify these countries based the their embeddedness, measured using the relation between the centrality of a country's firms on the national and the global scale of the board interlock network.

最后,通过采取不同国家间的持久性和优势度评估,根据它们的嵌入性和衡量国内公司在本国和全球规模的董事连锁网络中的中心性关系,对这些国家进行分类。

译文建议:

1.标题呢?

2.“edges representing shared directors between these firms”:“...条边代表这些公司的共同主管”

3.“investigate the topology as well as the concept of centrality in corporate networks at a global scale”:“研究全球范围的公司网络的拓扑和中心性概念”

4.“metrics”:“度量”

5.“ comparing the centrality ranking of a partition to that of the full network”:“比较分区和全部网络的中心度级别”

6.“Using the notion of centrality persistence we propose to measure”:用我们提出的中心性持久度概念去测量”

7.“In the board interlock network, it allows us to assess the extent to which the footprint of a national network is still present within the global network.”:“在董事连锁网络中,我们可以用它来评估一个国家网络的印迹在多大程度上还存留在全球网络中。”

8.漏译“Next”

9.“comparing these two new measures of”:“通过比较这两种新的度量”

人工蜕变:转变的进化设计,软体机器人(Artificial Metamorphosis: Evolutionary Design of Transforming, Soft-Bodied Robots)

Michał Joachimczak,Reiji Suzuki,Takaya Arita

(Translated by 胡鹏博)


We show how the concept of metamorphosis, together with a biologically inspired model of multicellular development, can be used to evolve soft-bodied robots that are adapted to two very different tasks, such as being able to move in an aquatic and in a terrestrial environment. Each evolved solution defines two pairs of morphologies and controllers, together with a process of transforming one pair into the other. Animats develop from a single cell and grow through cellular divisions and deaths until they reach an initial larval form adapted to a first environment. To obtain the adult form adapted to a second environment, the larva undergoes metamorphosis, during which new cells are added or removed and its controller is modified. Importantly, our approach assumes nothing about what morphologies or methods of locomotion are preferred. Instead, it successfully searches the vast space of possible designs and comes up with complex, surprising, lifelike solutions that are reminiscent of amphibian metamorphosis. We analyze obtained solutions and investigate whether the morphological changes during metamorphosis are indeed adaptive. We then compare the effectiveness of three different types of selective pressures used to evolve metamorphic individuals. Finally, we investigate potential advantages of using metamorphosis to automatically produce soft-bodied designs by comparing the performance of metamorphic individuals with their specialized counterparts and designs that are robust to both environments.


我们提出了一种将生物发育过程中的蜕变概念和源于生物学的多细胞发育模型相结合的方法,用于软体机器人演化设计。这种软体机器人可以完成两种不同的任务,包括在水面上和陆地上移动。每个进化方案定义了两种形态和控制器,以及可以将一种转换成另一种的方法。我们的程序从单个细胞开始生长,经过分化和死亡发育成初始幼体,然后对第一种环境进行适应。为了获得适应第二种环境的成体,幼体会经历蜕变,在此过程中新的细胞将会增加或者移除,而控制器也被调节。重要的是,我们的方法并没有假设什么样子的蜕变或者运动的方式是最合理的。然而,我们的方法成功的搜索了庞大的可能设计方案空间,然后得到了复杂的、令人震惊的、类似于生命的解决方案,这个方案与两栖动物蜕变的过程隐约吻合。我们分析了得到的方案,并探查了蜕变过程中的形态改变是否具有适应性。我们紧接着又比较了三种不同类型的选择压力对演化可蜕变个体的的有效性。最后,我们通过比较可蜕变个体的表现和它们的专业化部件及设计对于环境的鲁棒性,来探究使用蜕变来自动生成软体设计的潜在优势。

原文链接:http://www.mitpressjournals.org/doi/abs/10.1162/ARTL_a_00207#.V4OVIBV97IV

从博弈角度看生物的多细胞化 Games of multicellularity

Kamran Kaveh, Carl Veller, Martin A. Nowak

(translated by - 魏达)


Evolutionary game dynamics are often studied in the context of different population structures. Here we propose a new population structure that is inspired by simple multicellular life forms. In our model, cells reproduce but can stay together after reproduction. They reach complexes of a certain size, n, before producing single cells again. The cells within a complex derive payoff from an evolutionary game by interacting with each other. The reproductive rate of cells is proportional to their payoff. We consider all two-strategy games. We study deterministic evolutionary dynamics with mutations, and derive exact conditions for selection to favor one strategy over another. Our main result has the same symmetry as the well-known sigma condition, which has been proven for stochastic game dynamics and weak selection. For a maximum complex size of n=2 our result holds for any intensity of selection. For n > 2 it holds for weak selection. As specific examples we study the prisoner's dilemma and hawk-dove games. Our model advances theoretical work on multicellularity by allowing for frequency-dependent interactions within groups.


对演化博弈动力学的研究通常需要针对不同的种群结构。受简单多细胞生命形式的启发,在此我们提出一种新的种群结构。具体而言,种群中的细胞可以分裂,分裂所得的子代细胞亦可不必分离。以此种方式,细胞会在再次产生新的单个细胞之前聚集为大小为n的复合体。在复合体中,细胞相互博弈,并从演化博弈中获得回报。细胞的繁殖率正比于回报。

本文研究了所有「双策略博弈」(two-strategy games)的情形,并在考虑细胞变异的情况下,研究了决定论的演化动力学过程,推导出一个策略淘汰另一策略的精确条件。本文主要结果与著名的sigma条件(sigma condition)具有相同的对称性;后者在「随机博弈动力学」和「弱选择」中已被证明。对产生新细胞前的最大复合体大小(n)为2的情形,我们的结果适用于任何强度的自然选择;对n>2的情况,则适用于「弱选择过程」。在本文中,我们还将以「囚徒困境」和「鹰鸽博弈」为具体的案例进行分析。

我们的模型的先进之处,在于拓展了当下理解「生物多细胞化」(multicellularity)的理论框架,成功将「基于基因型频率的种群内相互作用」(frequency-dependent interaction within groups)纳入其中。

原文链接:http://arxiv.org/abs/1605.07690

原文下载:http://arxiv.org/pdf/1605.07690v1.pdf

基于结构的非线性动力学复杂网络控制(Structure-based control of complex networks with nonlinear dynamics)

Jorge G. T. Zañudo, Gang Yang, Réka Albert

(Translated by 陈开壮)

What can we learn about controlling a system solely from its underlying network structure? Here we use a framework for control of networks governed by a broad class of nonlinear dynamics that includes the major dynamic models of biological, technological, and social processes. This feedback-based framework provides realizable node overrides that steer a system towards any of its natural long term dynamic behaviors, regardless of the dynamic details and system parameters. We use this framework on several real networks, compare its predictions to those of classical structural control theory, and identify the topological characteristics that underlie the observed differences. Finally, we demonstrate this framework's applicability in dynamic models of gene regulatory networks and identify nodes whose override is necessary for control in the general case, but not in specific model instances.

仅从系统隐藏的网络结构中,我们对一个系统的控制能知道些什么呢?本文我们采用了一种复杂网络的控制框架,这些控制过程都是被一大类广泛存在的非线性动力学过程中所制约,它们涵盖了生物、技术、社会过程的主要动力学模型。在不考虑动力学细节和系统参数的情况下,这种基于反馈的框架提供了可实现的节点覆盖从而驱使系统可以演化至任何自然的长期动力学行为。我们对几个真实的网络使用了这种框架,将其与经典结构控制理论的预测进行比较,并识别出隐藏在所观察到的差异背后的拓扑特性。最后,我们证明了这种框架适用于基因调控网络的动态模型,并识别出了对一般情形的控制是必要的但在特定模型实例中并不必要的需要覆盖的调控节点。

原文链接:http://arxiv.org/abs/1605.08415

原文下载: http://120.52.73.76/arxiv.org/pdf/1605.08415v2.pdf

捕食者如何攻击决定了集群行为的演化(Evolution of Swarming Behavior Is Shaped by How Predators Attack)*

Randal S. Olson,David B. Knoester,Christoph Adami

(Translated by 王继康)


Animal grouping behaviors have been widely studied due to their implications for understanding social intelligence, collective cognition, and potential applications in engineering, artificial intelligence, and robotics. An important biological aspect of these studies is discerning which selection pressures favor the evolution of grouping behavior. In the past decade, researchers have begun using evolutionary computation to study the evolutionary effects of these selection pressures in predator-prey models. The selfish herd hypothesis states that concentrated groups arise because prey selfishly attempt to place their conspecifics between themselves and the predator, thus causing an endless cycle of movement toward the center of the group. Using an evolutionary model of a predator-prey system, we show that how predators attack is critical to the evolution of the selfish herd. Following this discovery, we show that density-dependent predation provides an abstraction of Hamilton's original formulation of domains of danger. Finally, we verify that density-dependent predation provides a sufficient selective advantage for prey to evolve the selfish herd in response to predation by coevolving predators. Thus, our work corroborates Hamilton's selfish herd hypothesis in a digital evolutionary model, refines the assumptions of the selfish herd hypothesis, and generalizes the domain of danger concept to density-dependent predation.

动物的集群行为对理解社会智能、集体认知,以及在人工智能、机器人等工程领域有着潜在的广泛应用,故而得到了大量的研究。这些研究在生物学中的一个重要因素是甄别哪些选择压力有利于集群行为的进化。在过去的十年中,研究者已经开始用演化算法来研究在捕食模型中这些选择压力的影响。自私集群(selfish herding)假设认为之所以群组会发生聚集,是因为自私的被捕食者会想办法让它们的同类处于它们和捕食者之间,这就导致了一个无限的循环运动过程使得整体趋向于被捕食者组织的中心。运用捕食系统的演化模型,我们展示了捕食者攻击对自私集群演化的决定性作用。紧接着,我们发现密度依赖的捕食作用提供了一种抽象,用以描述哈密顿所说的“危险区域”(domains of danger)的原始框架。最后,我们证实了密度依赖的捕食为被捕食者演化出自私集群效应提供了充足的选择优势,从而面对共同演化的捕食者。因此,我们的工作证实了在数字演化模型中的哈密顿自私集群假设,完善了该假设的前提,并且把危险区域概念推广到密度依赖捕食中。

原文链接:Olson, Randal S., David B. Knoester, and Christoph Adami. "Evolution of swarming behavior is shaped by how predators attack." Artificial life (2016).

生命起源前的化学反应(Beyond prebiotic chemistry)

Leroy Cronin,Sara Imari Walker

(To be translated by 一王小调)


How can matter transition from the nonliving to the living state? The answer is essential for understanding the origin of life on Earth and for identifying promising targets in the search for life on other planets. Most studies have focused on the likely chemistry of RNA, protein, lipid, or metabolic “worlds” and autocatalytic sets, including attempts to make life in the lab. But these efforts may be too narrowly focused on the biochemistry of life as we know it today. A radical rethink is necessary, one that explores not just plausible chemical scenarios but also new physical processes and driving forces. Such investigations could lead to a physical understanding not only of the origin of life but also of life itself, as well as to new tools for designing artificial biology.

物质是如何从非生命转变为生命状态的呢?这个问题对于理解地球生命的起源和寻找可能存在的外星生命都具有十分重要的意义。大多数研究的关注点在于可能的化学物质,例如RNA、蛋白质、脂质及其代谢过程以及自催化组,也包括试图在实验室里创造生命的尝试。但是这些研究都过分狭隘地局限在我们今天已知的生物化学过程之中。从根本上改变这一思路显得尤为必要,起到关键作用的可能不仅仅是一个化学的环境,而可能是一个全新的物理过程以及驱动力。这样的研究可能会为我们带来对于生命的物理化的认识,这一认识将不再仅仅有助于生命起源的认识,更是对于生命本身的理解。这将有助于人们发现新的方法来设计人造生命。

原文链接:http://science.sciencemag.org/content/352/6290/1174?et_rid=34816647&et_cid=531910

生命起源问题中信息价值的计算理论路线(A Roadmap for a Computational Theory of the Value of Information in Origin of Life Questions)

Soumya Banerjee

(Translated by 一)


Information plays a critical role in complex biological systems. Complex systems like immune systems and ant colonies co-ordinate heterogeneous components in a decentralized fashion. How do these distributed decentralized systems function? One key component is how these complex systems efficiently process information. These complex systems have an architecture for integrating and processing information coming in from various sources and points to the value of information in the functioning of different complex biological systems. This paper proposes a role for information processing in questions around the origin of life and suggests how computational simulations may yield insights into questions related to the origin of life.

Such a computational model of the origin of life would unify thermodynamics with information processing and we would gain an appreciation of why proteins and nucleotides evolved as the substrate of computation and information processing in living systems that we see on Earth. Answers to questions like these may give us insights into non-carbon based forms of life that we could search for outside Earth.

We hypothesize that carbon-based life forms are only one amongst a continuum of life-like systems in the universe. Investigations into the role of computational substrates that allow information processing is important and could yield insights into: 1) novel non-carbon based computational substrates that may have "life-like" properties, and 2) how life may have actually originated from non-life on Earth. Life may exist as a continuum between non-life and life and we may have to revise our notion of life and how common it is in the universe. Looking at life or life-like phenomenon through the lens of information theory may yield a broader view of life.

信息在复杂生物系统中起到关键的作用。像免疫系统和蚁群这样的复杂系统可以去中心化地协调不同组件。这些分布式的去中心化系统是怎样工作的呢?关键是这些复杂系统如何有效地处理信息。这些复杂系统有整合处理信息的架构,以处理不同来源的信息,并评估信息在不同复杂生命系统中的价值。本文关注生命起源相关问题中的信息处理过程,展示如何可以从计算模拟中获得对关于生命起源的问题的洞察。

这样的生命起源的计算模型将热力学和信息处理过程统一起来,我们将理解为什么蛋白质和核苷酸会成为地球生物系统中计算和信息处理的基质。类似问题的回答可以让我们更好地理解外太空非碳基生物形式。

我们假设碳基生命只是宇宙中类生命系统连续谱中的一种。那么研究容许信息处理的计算物质的作用就非常重要,它可以让我们更好地理解: 1)具有类生命特性的非碳基计算物质; 2)地球生命如何从非生命演化而来。 生命可能只是从非生命到生命的连续谱中的一个存在状态,也许我们需要重新认识生命以及它在宇宙中的普遍性。透过信息论的视角观察生命和类生命现象或许可以带来更普适的生命观。


https://www.researchgate.net/profile/Soumya_Banerjee/publication/303753263_A_Roadmap_for_a_Computational_Theory_of_the_Value_of_Information_in_Origin_of_Life_Questions/links/5750d51208ae1c34b39c95ae.pdf

Small groups and long memories promote cooperation

Alexander J. Stewart & Joshua B. Plotkin

(Translated by 一 F7)


Complex social behaviors lie at the heart of many of the challenges facing evolutionary biology, sociology, economics, and beyond. For evolutionary biologists the question is often how group behaviors such as collective action, or decision making that accounts for memories of past experience, can emerge and persist in an evolving system. Evolutionary game theory provides a framework for formalizing these questions and admitting them to rigorous study. Here we develop such a framework to study the evolution of sustained collective action in multi-player public-goods games, in which players have arbitrarily long memories of prior rounds of play and can react to their experience in an arbitrary way. We construct a coordinate system for memory-m strategies in iterated n-player games that permits us to characterize all cooperative strategies that resist invasion by any mutant strategy, and stabilize cooperative behavior. We show that, especially when groups are small, longer-memory strategies make cooperation easier to evolve, by increasing the number of ways to stabilize cooperation. We also explore the co-evolution of behavior and memory. We find that even when memory has a cost, longer-memory strategies often evolve, which in turn drives the evolution of cooperation, even when the benefits for cooperation are low.

复杂的社会行为是演化生物学、社会学、经济学等众多领域的中心。进化生物学家要解决的问题通常是有利于记忆过去经验的集体行动、决策等群体行为是如何在演化系统中涌现并持续保留下去的。演化博弈理论将这些问题理论化,为严肃的学术研究构建了一个系统性框架。在此,我们开发了这样一个框架以研究在多玩家的公共产品游戏中持续的集体行动的演变,在游戏中玩家有任意长的记忆前几轮游戏的能力,并可以灵活运用自己的经验。我们还构建了一个在n人迭代游戏中允许我们记住m条策略的协作系统,以确保系统可以处理所有的合作策略,抵抗入侵的任何突变策略以及稳定合作行为。我们的研究工作表明,当群体的数量很小时,较长的记忆策略能使合作更容易形成,增加主体的数量,能够让合作稳定下来。我们还探讨了行为和记忆的耦合性,发现即使记忆存在成本,更长的记忆策略往往会涌现出来,这反过来又推动了合作的进化,即使是在合作的好处很少的时候。


原文链接:http://www.nature.com/articles/srep26889

原文下载:http://www.nature.com/articles/srep26889.pdf

超越齐夫定律:Lavalette(拉瓦莱特)排序函数及其性质(Beyond Zipf's Law: The Lavalette Rank Function and its Properties)

Oscar Fontanelli, Pedro Miramontes, Yaning Yang, Germinal Cocho, Wentian Li

(Translated by Darthy)

Although Zipf's law is widespread in natural and social data, one often encounters situations where one or both ends of the ranked data deviate from the power-law function. Previously we proposed the Beta rank function to improve the fitting of data which does not follow a perfect Zipf's law. Here we show that when the two parameters in the Beta rank function have the same value, the Lavalette rank function, the probability density function can be derived analytically. We also show both computationally and analytically that Lavalette distribution is approximately equal, though not identical, to the lognormal distribution. We illustrate the utility of Lavalette rank function in several datasets. We also address three analysis issues on the statistical testing of Lavalette fitting function, comparison between Zipf's law and lognormal distribution through Lavalette function, and comparison between lognormal distribution and Lavalette distribution.



齐普夫定律是指在自然语言的语料库中,如果将所有单词按照频次降序排序,一个单词出现的频率与它的排名成反比,更为严格的,二者呈现幂律关系。该现象作为任何与“幂律分布”相关的事物的参考,广泛存在于自然和社会科学分析数据中,然而,我们经常会碰到排序后一端或两端的长尾偏离幂律分布的统计数据。在之前的研究中,我们提出当数据分布与齐普夫定律不完全匹配时,可以使用Beta排序函数来提高数据的拟合度。在本文中,我们发现,如果拟合的Beta函数的两个参数值相同,我们可以解析地给出Lavalette排序函数(拉瓦莱特函数)。我们的研究结果进一步表明,Lavalette分布与对数正态分布在计算和分析上的性质近似相同。我们在几个数据集上验证了使用Lavalette'排序'函数的可行性。进一步,我们还提出了三个值得分析的问题:Lavalette函数拟合的统计检验,使用Lavalette函数来比较齐夫定律和对数正态分布,以及对数正态分布和Lavalette分布的比较。

原文链接:Beyond Zipf's Law: The Lavalette Rank Function and its Properties
原文下载:https://arxiv.org/pdf/1606.01959v1.pdf

行为控制,还是数字民主?——一份数字宣言(Behavioural Control or Digital Democracy? - A Digital Manifesto)

"This is the English translation of the Digital Manifesto,which appeared in Spektrum der Wissenschaft"

Dirk Helbing,Bruno S.Frey,Gerd Gigerenzer,Andrej Zwitter

(Translated by 一女周瑜)

“The digital revolution is in full swing. Everything will become intelligent. The field of Artificial Intelligence is making breath-taking advances. The way in which we organize the economy and society will change fundamentally. Society is at a crossroads, which promises great opportunities, but also considerable risks. Today, algorithms know pretty well what we do, what we think and how we feel. The trend goes from programming computers to programming people. However, the idea of replacing the thinking of all citizens by a computer cluster would be absurd. This causes social polarization, resulting in the formation of separate groups that no longer understand each other and find themselves increasingly at conflict with one another. Finally, the result is a fragmentation, possibly even a disintegration of society. If such widespread technologies are not compatible with our society's core values, sooner or later they will cause extensive damage. They could lead to an automated society with totalitarian features. Therefore, Centralized, top-down control is a solution of the past, which is only suitable for systems of low complexity. With the economic and cultural evolution, social complexity will continue to rise, the solution for the future is collective intelligence. This means that citizen science, crowdsourcing and online discussion platforms are eminently important new approaches to making more knowledge, ideas and resources available. Therefore, we urge to adhere to some fundamental principles and adopt series of strategical actions to ensure a right path that allows us all to benefit from the digital revolution.”

数字革命正如火如荼地进行着。一切都将变得智能化。人工智能领域也正取得惊人的进步。我们组织经济和社会的方式将从根本上发生改变。社会正处在一个十字路口,存在巨大的机遇,但也存在相当大的风险。当前,算法可以很好地知道我们要做什么、想什么,我们感觉如何,这是一个从为计算机编程向为人“编程”发展的时代。然而,用一个计算机集群来代替所有公民思考的想法是荒谬的。这将带来社会的两极分化,导致不同群体的形成,这些群体不再相互理解并且彼此间产生更多冲突,最终结果是碎片化,甚至可能瓦解整个社会。如果这些广泛应用的技术与我们社会的核心价值观不兼容,他们迟早会引发大范围的破坏。它们可能会导致一个具有极权主义特征的自动化社会。因此,集中的、自上而下的控制是一个过时的解决方案,它只适合于低复杂度的系统。而随着经济和文化的发展,社会的复杂度将继续上升,未来的解决方案是群体智慧。这意味着公民科学,众包和在线讨论平台将成为产生知识、获得想法和资源的极为重要的新方法。因此,我们敦促坚持一些基本原则和采取系列战略行动,以确保一条让我们从数字革命中受益的正确道路。

原文下载:https://www.researchgate.net/publication/303813069_Behavioural_Control_or_Digital_Democracy_-_A_Digital_Manifesto

原文链接:http://www.spektrum.de/pdf/digital-­‐manifest/1376682

扩大开放获取的影响力——维基百科与科学传播(Amplifying the Impact of Open Access: Wikipedia and the Diffusion of Science)

Misha Teplitskiy, Grace Lu, Eamon Duede

( Translated by Dandelion11)


With the rise of Wikipedia as a first-stop source for scientific knowledge, it is important to compare its representation of that knowledge to that of the academic literature. Here we identify the 250 most heavily used journals in each of 26 research fields (4,721 journals, 19.4M articles in total) indexed by the Scopus database, and test whether topic, academic status, and accessibility make articles from these journals more or less likely to be referenced on Wikipedia. We find that a journal's academic status (impact factor) and accessibility (open access policy) both strongly increase the probability of it being referenced on Wikipedia. Controlling for field and impact factor, the odds that an open access journal is referenced on the English Wikipedia are 47% higher compared to paywall journals. One of the implications of this study is that a major consequence of open access policies is to significantly amplify the diffusion of science, through an intermediary like Wikipedia, to a broad audience.


随着维基百科成为获得科学知识的首要来源,比较维基百科和学术文献的知识表示就很重要了。我们从Scopus文献数据库中选出了在26个研究领域中分别被引用最多的250种学术期刊(共计4721种,19.4M),并测试了文献标题、学术地位和可获取性是否会影响文献在维基百科中的被引用率。研究发现,文献的学术地位(影响力)高、可获取性(开放获取)强,会大大提高文献在维基百科被引用的几率。在学术领域和影响力因素既定的情况下,开放获取期刊在英文维基百科被引用的几率比付费期刊高了47%。这项研究暗示我们:开放获取的一个重要成果就是通过维基百科等媒介,可以显著扩大科学面向大众传播的力度。


原文链接:http://arxiv.org/abs/1506.07608

原文下载:https://arxiv.org/ftp/arxiv/papers/1506/1506.07608.pdf

人体微生物动力学的普适性 (Universality of human microbial dynamics)

Amir Bashan,Travis E. Gibson,Jonathan Friedman,Vincent J. Carey,Scott T. Weiss,Elizabeth L.Hohmann&Yang-Yu Liu

(Translated by 刘清晴)


Human-associated microbial communities have a crucial role in determining our health and well-being1, and this has led to the continuing development of microbiome-based therapies3 such as faecal microbiota transplantation. These microbial communities are very complex, dynamic and highly personalized ecosystems, exhibiting a high degree of inter-individual variability in both species assemblages and abundance profiles. It is not known whether the underlying ecological dynamics of these communities, which can be parameterized by growth rates, and intra- and inter-species interactions in population dynamics models, are largely host-independent (that is, universal) or host-specific. If the inter-individual variability reflects host-specific dynamics due to differences in host lifestyle, physiology or genetics, then generic microbiome manipulations may have unintended consequences, rendering them ineffective or even detrimental. Alternatively, microbial ecosystems of different subjects may exhibit universal dynamics, with the inter-individual variability mainly originating from differences in the sets of colonizing species. Here we develop a new computational method to characterize human microbial dynamics. By applying this method to cross-sectional data from two large-scale metagenomic studies—the Human Microbiome Project and the Student Microbiome Project—we show that gut and mouth microbiomes display pronounced universal dynamics, whereas communities associated with certain skin sites are probably shaped by differences in the host environment. Notably, the universality of gut microbial dynamics is not observed in subjects with recurrent Clostridium difficile infection17 but is observed in the same set of subjects after faecal microbiota transplantation. These results fundamentally improve our understanding of the processes that shape human microbial ecosystems, and pave the way to designing general microbiome-based therapies.

与人类相关的微生物群体对于人类的健康和幸福具有重要意义,使得微生物组学疗法(microbiome-based therapy),如粪便微生物群移植(faecal microbiota transplantation)等,得以持续发展。这些寄生于人体的微生物群体是成分复杂,动态变化且高度个性化的生态系统,其物种构成和丰饶程度都在不同人类个体之间展现出高度的多样性。这些微生物群体背后的生态动力学可以被参数化地表示为生长率以及人口动力学模型(population dynamics models)中的种内和种间相互作用。这些生态动力学特征主要是宿主无关的(即普适性的)还是宿主特异的,目前尚不可知。如果人类个体间的微生物群体多样性是通过宿主的生活方式、生理或遗传学上的差异反映的宿主特异性的动力学特征,那么一般的微生物学操作可能会导致意外的结果,致使这些操作失效,甚至得到误导性的结论。如果不同宿主间的微生物生态系统显示出普适性的动力学特征,则其人类个体间微生物群体多样性主要来源于微生物群体本身的差异。在此,我们发展出一套新的计算方法来描绘人类微生物群体的动力学特征。我们将这种计算方法用于对两种大尺度的元基因组(metagenomic)研究——人类微生物组计划和学生微生物组计划——的数据进行了横向比较,我们发现,肠道与口腔微生物群体呈现出显著的普适性动力学特征,然而皮肤特定部位的微生物群体则可能随着寄生环境的不同而不同。特别地,肠道微生物群体动力学的普适性并没有在复发性艰难梭菌(recurrent Clostridium difficile infection)患者中发现,但是却可以在接受了粪便微生物群移植的患者中观察到。这些结果从根本上加深了我们对于人类微生物生态系统形成过程的理解,并为设计普适性的微生物组学疗法铺平了道路。

原文链接:http://www.nature.com/nature/journal/v534/n7606/full/nature18301.html