Bruce Hannon is known to many for his weekly email digest highlighting interesting articles, published in various well regarded complexity sources, that span the gamut from all areas of research and inquiry, from the life sciences to the social sciences. What all the articles have in common is that they celebrate interesting findings, provocative theories, and the complexity of the world. Bruce has graciously agreed to allow InnoCentive to repost his “Complexity” Digest from time to time. Thank you Bruce!
Below, you will find Bruce’s “Complexity” Digest #5, we hope you enjoy. Please let us know your feedback and feel free to respond to the blog posts and share your thoughts and reactions with others.
Catastrophic cascade of failures in interdependent networks, Nature
Excerpt: Complex networks have been studied intensively for a decade, but research still focuses on the limited case of a single, non-interacting network. Modern systems are coupled together and therefore should be modelled as interdependent networks. A fundamental property of interdependent networks is that failure of nodes in one network may lead to failure of dependent nodes in other networks. This may happen recursively and can lead to a cascade of failures.
- Source: Catastrophic cascade of failures in interdependent networks, Sergey V. Buldyrev, Roni Parshani, Gerald Paul, H. Eugene Stanley, Shlomo Havlin, DOI: 10.1038/nature08932, Nature 64, 1025-1028, 2010/04/15
Excerpt: BuRSTS is a performance in human dynamics, a game of cooperation and prediction, that will gradually unveil the full text of Bursts. In a nutshell, if you register at http://brsts.com, you will be able to adopt one of the 84,245 words of the book. Once you adopt, the words adopted by others will become visible to you -- thus as each words finds a parent, the whole book will become visible to the adopters. But if you invite your friends (and please do!) and you are good at predicting hidden content, the book will unveil itself to you well before all words are adopted. We will even send each day free signed copied of Bursts to those with the best scores.
See Also: http://brsts.com
- Source: BuRSTS, Albert-Laszlo Barabasi
Excerpt: Melanie Mitchell (...) takes us on a personal guided tour in Complexity. I emphasize personal because Mitchell (a computer scientist at Portland State University and SFI) uses her experience in evolutionary computation and artificial life to paint her picture of the history, and current state, of complexity research. Also, she writes in an unpretentious style with frequent entertaining and useful anecdotes that make one feel she is a trusted companion on the tour. Lastly, she focuses predominantly on computational aspects, with ecology, economics, and (perhaps surprisingly) neuroscience being notably less emphasized.
- Source: An Informative Itinerary, Iain D. Couzin, DOI: 10.1126/science.1187332, Science Vol. 328. no. 5977, p. 430, 2010/04/23
Economists need their own uncertainty principle, Nature
Summary: Bad risk management contributed to the current financial crisis. Two economists believe the situation could be improved by gaining a deeper understanding of what is not known.
- Source: Economists need their own uncertainty principle, Philip Ball, DOI: 10.1038/news.2010.157, Nature, 2010/04/05
VS Ramachandran: The neurons that shaped civilization, TED.com
About this talk: Neuroscientist Vilayanur Ramachandran outlines the fascinating functions of mirror neurons. Only recently discovered, these neurons allow us to learn complex social behaviors, some of which formed the foundations of human civilization as we know it.
- Source: VS Ramachandran: The neurons that shaped civilization, TED.com, 2010/01
Sam Harris: Science can answer moral questions, TED.com
About this talk: Questions of good and evil, right and wrong are commonly thought unanswerable by science. But Sam Harris argues that science can -- and should -- be an authority on moral issues, shaping human values and setting out what constitutes a good life.
- Source: Sam Harris: Science can answer moral questions, TED.com, 2010/03
Evolution of cooperation by natural selection, arXiv
Excerpt: The observed cooperation on the level of genes, cells, tissues, and individuals has been the object of intense study by evolutionary biologists,(...) We find that if stochastic strategies for the iterated Prisoner’s Dilemma (IPD) are encoded as genes, the environmental conditions that the strategies are adapting to determine the fixed point of the evolutionary trajectory. (...) These results imply that previous identifications of mechanisms that promote cooperation can be understood within a broader framework where increased predictability is sufficient for the evolution of cooperation
- Source: Evolution of cooperation by natural selection, Dimitris Iliopoulos, Arend Hintze, and Christoph Adami, arXiv:1004.2020, 2010/04/12
Portrait of a year-old pandemic, Nature
Excerpt: One year ago this month, the world watched with trepidation as a novel influenza A virus, to which the global population had little or no immunity, emerged in Mexico and the United States. In the weeks that followed, the H1N1 'swine flu' virus spread rapidly to countries worldwide, leading the World Health Organization (WHO) on 11 June 2009 to officially declare the first flu pandemic in more than 40 years. Nature looks at the lessons learnt from H1N1, and how they will help scientists and health authorities to handle the next flu pandemic.
- Source: Portrait of a year-old pandemic, Declan Butler, DOI: 10.1038/4641112a, Nature 464, 1112-1113, 2010/04/21
Extending Healthy Life Span�"From Yeast to Humans, Science
Excerpt: Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.
- Source: Extending Healthy Life Span—From Yeast to Humans, Luigi Fontana, Linda Partridge, Valter D. Longo, DOI: 10.1126/science.1172539, Science Vol. 328. no. 5976, pp. 321 - 326, 2010/04/23
No gain from brain training, Nature
Excerpt: The largest trial to date of 'brain-training' computer games suggests that people who use the software to boost their mental skills are likely to be disappointed.
- Source: No gain from brain training, Alla Katsnelson, DOI: 10.1038/4641111a, Nature 464, 1111, 2010/04/20
Complexity and Diversity, Science
Abstract: The mechanisms for the origin and maintenance of biological diversity are not fully understood. It is known that frequency-dependent selection, generating advantages for rare types, can maintain genetic variation and lead to speciation, but in models with simple phenotypes (that is, low-dimensional phenotype spaces), frequency dependence needs to be strong to generate diversity. However, we show that if the ecological properties of an organism are determined by multiple traits with complex interactions, the conditions needed for frequency-dependent selection to generate diversity are relaxed to the point where they are easily satisfied in high-dimensional phenotype spaces. Mathematically, this phenomenon is reflected in properties of eigenvalues of quadratic forms. Because all living organisms have at least hundreds of phenotypes, this casts the potential importance of frequency dependence for the origin and maintenance of diversity in a new light.
- Source: Complexity and Diversity, Michael Doebeli, Iaroslav Ispolatov, DOI: 10.1126/science.1187468, Science Vol. 328. no. 5977, pp. 494 - 497, 2010/04/23
Hierarchical modularity in human brain functional networks, arXiv
Excerpt: The idea that complex systems have a hierarchical modular organization originates in the early 1960s and has recently attracted fresh support from quantitative studies of large scale, real-life networks. Here we investigate the hierarchical modular (or "modules-within-modules") decomposition of human brain functional networks, (...) Results show that human brain functional networks have a hierarchical modular organization with a fair degree of similarity between subjects, I=0.63.(...) We conclude that methods are available for hierarchical modular decomposition of large numbers of high resolution brain functional networks using computationally expedient algorithms. This could enable future investigations of Simon's original hypothesis that hierarchy or near-decomposability of physical symbol systems is a critical design feature for their fast adaptivity to changing environmental conditions.
- Source: Hierarchical modularity in human brain functional networks, D. Meunier, R. Lambiotte, A. Fornito, K.D. Ersche and E.T. Bullmore, arXiv:1004.3153, 2010/04/19
Organizations: Social Systems Conducting Experiments, Springer
What are organizations? What is their point? How should one design successful organizations? Although these questions have been treated by many authors in many different ways, this book offers a new perspective. In a nutshell, the book combines cybernetics, social systems theory and Aristotle’s ethics to describe organizations as "social systems conducting experiments with their survival" and to formulate principles for their design. The authors argue that ‘experimenting’ and ‘social interaction’ are key features of organizations. In order to survive, organizations continuously have to experiment with goals, infrastructures and transformation processes and this experiment is an inherently social activity. (...)
- Source: Organizations: Social Systems Conducting Experiments, Jan Achterbergh, Dirk Vriens, Springer, 2009/10/01
The Doctrine of Chances: Probabilistic Aspects of Gambling,Springer
Three centuries ago Montmort and De Moivre published two of the first books on probability theory, then called the doctrine of chances, emphasizing its most important application at that time, games of chance. This volume, on the probabilistic aspects of gambling, is a modern version of those classics. While covering the classical material such as house advantage and gambler's ruin, it also takes up such 20th-century topics as martingales, Markov chains, game theory, bold play, and optimal proportional play. In addition there is extensive coverage of specific casino games such as roulette, craps, video poker, baccarat, and twenty-one.
- Source: The Doctrine of Chances: Probabilistic Aspects of Gambling, Stewart N. Ethier, Springer, 2010/05/01