Compilado AZyNE 30-03

Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure, Science

Abstract: Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species’ history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture.

• Source: Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure, Kim R. Hill, Robert S. Walker, Miran Božičević, James Eder, Thomas Headland, Barry Hewlett, A. Magdalena Hurtado, Frank Marlowe, Polly Wiessner, and Brian Wood, DOI: 10.1126/science.1199071, Science Vol. 331 no. 6022 pp. 1286-1289, 2011/03/11

Danny Hillis: Understanding cancer through proteomics, TED.com

About this talk: Danny Hills makes a case for the next frontier of cancer research: proteomics, the study of proteins in the body. As Hillis explains it, genomics shows us a list of the ingredients of the body -- while proteomics shows us what those ingredients produce. Understanding what's going on in your body at the protein level may lead to a new understanding of how cancer happens.

• Source: Danny Hillis: Understanding cancer through proteomics, TED.com, 2011/03
• VIDEO - Watch this talk

Deb Roy: The birth of a word, TED.com

About this talk: MIT researcher Deb Roy wanted to understand how his infant son learned language -- so he wired up his house with videocameras to catch every moment (with exceptions) of his son's life, then parsed 90,000 hours of home video to watch "gaaaa" slowly turn into "water." Astonishing, data-rich research with deep implications for how we learn.

• Source: Deb Roy: The birth of a word, TED.com, 2011/03
• VIDEO - Watch this talk

Has the Earth’s sixth mass extinction already arrived?, Nature

Abstract: Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

• Source: Has the Earth’s sixth mass extinction already arrived?, Anthony D. Barnosky, Nicholas Matzke, Susumu Tomiya, Guinevere O. U. Wogan, Brian Swartz, Tiago B. Quental, Charles Marshall, Jenny L. McGuire, Emily L. Lindsey, Kaitlin C. Maguire, Ben Mersey & Elizabeth A. Ferrer, DOI: 10.1038/nature09678, Nature 471, 51�"57, 2011/03/03

Nonlinear deterministic equations in biological evolution, arXiv

Abstract: We review models of biological evolution in which the population frequency changes deterministically with time. If the population is self-replicating, although the equations for simple prototypes can be linearised, nonlinear equations arise in many complex situations. For sexual populations, even in the simplest setting, the equations are necessarily nonlinear due to the mixing of the parental genetic material. The solutions of such nonlinear equations display interesting features such as multiple equilibria and phase transitions. We mainly discuss those models for which an analytical understanding of such nonlinear equations is available.

• Source: Nonlinear deterministic equations in biological evolution, Kavita Jain and Sarada Seetharaman, arXiv:1103.0097, 2011/03/01

Selection for smaller brains in Holocene human evolution, arXiv

Abstract: Background: Human populations during the last 10,000 years have undergone rapid decreases in average brain size as measured by endocranial volume or as estimated from linear measurements of the cranium. A null hypothesis to explain the evolution of brain size is that reductions result from genetic correlation of brain size with body mass or stature.
Results: The absolute change of endocranial volume in the study samples was significantly greater than would be predicted from observed changes in body mass or stature.
Conclusions: The evolution of smaller brains in many recent human populations must have resulted from selection upon brain size itself or on other features more highly correlated with brain size than are gross body dimensions. This selection may have resulted from energetic or nutritional demands in Holocene populations, or to life history constraints on brain development.

• Source: Selection for smaller brains in Holocene human evolution, John Hawks, arXiv:1102.5604, 2011/02/28

Compilado AZyNE 29-01

The Newest Synthesis: Understanding the Interplay of Evolutionary and Ecological Dynamics, Science

Excerpt: The effect of ecological change on evolution has long been a focus of scientific research. The reverse�"how evolutionary dynamics affect ecological traits�"has only recently captured our attention, however, with the realization that evolution can occur over ecological time scales. This newly highlighted causal direction and the implied feedback loop�"eco-evolutionary dynamics�"is invigorating both ecologists and evolutionists and blurring the distinction between them.

• Source: The Newest Synthesis: Understanding the Interplay of Evolutionary and Ecological Dynamics, Thomas W. Schoener, DOI: 10.1126/science.1193954, Science Vol. 331 no. 6016 pp. 426-429, 2011/01/28

Swarm intelligence in plant roots, Trends in Ecology & Evolution

Excerpt: (...) swarm intelligence occurs when two or more individuals independently, or at least partly independently, acquire information that is processed through social interactions and is used to solve a cognitive problem in a way that would be impossible for isolated individuals. We propose at least one example of swarm intelligence in plants: coordination of individual roots in complex root systems.

• Source: Swarm intelligence in plant roots, František Baluška, Simcha Lev-Yadun, Stefano Mancuso, DOI: 10.1016/j.tree.2010.09.003, Trends in Ecology & Evolution, Volume 25, Issue 12, 682-683, 2010/12

Primitive agriculture in a social amoeba, Nature

Excerpt: Here we show that the social amoeba Dictyostelium discoideum has a primitive farming symbiosis that includes dispersal and prudent harvesting of the crop. About one-third of wild-collected clones engage in husbandry of bacteria. Instead of consuming all bacteria in their patch, they stop feeding early and incorporate bacteria into their fruiting bodies. They then carry bacteria during spore dispersal and can seed a new food crop, which is a major advantage if edible bacteria are lacking at the new site.

• Source: Primitive agriculture in a social amoeba, Debra A. Brock, Tracy E. Douglas, David C. Queller & Joan E. Strassmann, DOI: 10.1038/nature09668, Nature 469, 393�"396, 2011/01/19

Infectious moods: How bugs control your mind, New Scientist

Excerpt: Now it seems the immune system, and infections that stimulate it, can influence our moods, memory and ability to learn. Some strange behaviours, such as obsessive compulsive disorder, may be triggered by infections, and the immune system may even shape our basic personalities, such as how anxious or impulsive we are.

• Source: Infectious moods: How bugs control your mind, New Scientist, 2011/01/12

Morphological change in machines accelerates the evolution of robust behavior, PNAS

Excerpt: Most animals exhibit significant neurological and morphological change throughout their lifetime. No robots to date, however, grow new morphological structure while behaving. This is due to technological limitations but also because it is unclear that morphological change provides a benefit to the acquisition of robust behavior in machines. Here I show that in evolving populations of simulated robots, if robots grow from anguilliform into legged robots during their lifetime in the early stages of evolution, and the anguilliform body plan is gradually lost during later stages of evolution, gaits are evolved for the final, legged form of the robot more rapidly�"and the evolved gaits are more robust�"compared to evolving populations of legged robots that do not transition through the anguilliform body plan.

• Source: Morphological change in machines accelerates the evolution of robust behavior, Josh Bongard, DOI: 10.1073/pnas.1015390108, PNAS Published online before print, 2011/01/10
• VIDEO - A typical gait discovered for the hexapod when it experiences ontogenetic and topological change: It transitions from the legless form into an upright legged form over its lifetime.

Complexity through Recombination: From Chemistry to Biology, Entropy

Abstract: Recombination is a common event in nature, with examples in physics, chemistry, and biology. This process is characterized by the spontaneous reorganization of structural units to form new entities. Upon reorganization, the complexity of the overall system can change. In particular the components of the system can now experience a new response to externally applied selection criteria, such that the evolutionary trajectory of the system is altered. The link between chemical and biological forms of recombination is explored. (...) The results underscore the importance of recombination in the origins of life on the Earth and its subsequent evolutionary divergence.

• Source: Complexity through Recombination: From Chemistry to Biology, Niles Lehman et al., DOI: 10.3390/e13010017, Entropy, vol. 13, issue 1, pages 17-37, 2011/01/01

Mating strategies in primates: A game theoretical approach to infanticide, Journal of Theoretical Biology

Excerpt: Infanticide by newly immigrated or newly dominant males is reported among a variety of taxa, such as birds, rodents, carnivores and primates. Here we present a game theoretical model to explain the presence and prevalence of infanticide in primate groups. We have formulated a three-player game involving two males and one female and show that the strategies of infanticide on the males' part and polyandrous mating on the females' part emerge as Nash equilibria that are stable under certain conditions [...] These conclusions are confirmed by observations in the wild. These conclusions are confirmed by observations in the wild.

• Source: Mating strategies in primates: A game theoretical approach to infanticide, Lyon JE, Pandit SA, van Schaik CP, Pradhan GR, DOI: 10.1016/j.jtbi.2011.01.005, Journal of Theoretical Biology, in Press, January 2011

Peer review: Trial by Twitter, Nature

Summary: Blogs and tweets are ripping papers apart within days of publication, leaving researchers unsure how to react.

• Source: Peer review: Trial by Twitter, Apoorva Mandavilli, DOI: 10.1038/469286a, Nature 469, 286-287, 2011/01/19

Compilado AZyNE 24-01

Quantitative Analysis of Culture Using Millions of Digitized Books, Science

Abstract: We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of ‘culturomics,’ focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. Culturomics extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities.

• Source: Quantitative Analysis of Culture Using Millions of Digitized Books, Jean-Baptiste Michel, Yuan Kui Shen, Aviva Presser Aiden, Adrian Veres, Matthew K. Gray, The Google Books Team, Joseph P. Pickett, Dale Hoiberg, Dan Clancy, Peter Norvig, Jon Orwant, Steven Pinker, Martin A. Nowak, and Erez Lieberman Aiden, DOI: 10.1126/science.1199644, Science Vol. 331 no. 6014 pp. 176-182, 2011/01/14

Amber Case: We are all cyborgs now, TED.com

About this talk: Technology is evolving us, says Amber Case, as we become a screen-staring, button-clicking new version of homo sapiens. We now rely on "external brains" (cell phones and computers) to communicate, remember, even live out secondary lives. But will these machines ultimately connect or conquer us? Case offers surprising insight into our cyborg selves.

• Source: Amber Case: We are all cyborgs now, TED.com, 2011/01

The AHA! Experience: Creativity Through Emergent Binding in Neural Networks, Cognitive Science

Abstract: Many kinds of creativity result from combination of mental representations. This paper provides a computational account of how creative thinking can arise from combining neural patterns into ones that are potentially novel and useful. We defend the hypothesis that such combinations arise from mechanisms that bind together neural activity by a process of convolution, a mathematical operation that interweaves structures. We describe computer simulations that show the feasibility of using convolution to produce emergent patterns of neural activity that can support cognitive and emotional processes underlying human creativity.

• Source: The AHA! Experience: Creativity Through Emergent Binding in Neural Networks, Paul Thagard, Terrence C. Stewart, DOI: 10.1111/j.1551-6709.2010.01142.x, Cognitive Science Volume 35, Issue 1, pages 1�"33, January/February 2011, 2011/01-02

Plenty of Time

There's Plenty of Time for Evolution, PNAS

Abstract: Objections to Darwinian evolution are often based on the time required to carry out the necessary mutations. Seemingly, exponential numbers of mutations are needed. We show that such estimates ignore the effects of natural selection, and that the numbers of necessary mutations are thereby reduced to about K log L, rather than KL, where L is the length of the genomic “word,” and K is the number of possible “letters” that can occupy any position in the word. The required theory makes contact with the theory of radix-exchange sorting in theoretical computer science, and the asymptotic analysis of certain sums that occur there.

• Source: There's Plenty of Time for Evolution, Herbert S. Wilf, Warren J. Ewens, DOI: 10.1073/pnas.1016207107, PNAS, Published online before print, 2010/12/13

Wolfram Alpha o las posibilidades de maneras alternativas de acceso al conocimiento científico

Me referiré al sitio Wolfram Alpha http://www.wolframalpha.com/

Hace unos días me topé con este sitio. Me sentí gratamente impresionado porque en cierta medida estaba viendo un ejemplo cristalizado de una vaga idea que rondaba hace un rato mi cabeza. Esa idea respecto a cómo probablemente estaremos haciendo ciencia en unas décadas.
Hoy por hoy, en pleno refinamiento, creo que ya se nos ofrece una fuente muy interesante de información. Mucho mas refinada que simplemente "googlear". La explicitación de los supuestos de búsquedas y la contextualización de la información es, para la parte de mi cerebro que se regodea en lo analítico, mas que estimulante.

Por lo que pude probar es muy bueno para datos astronómicos, de "stock markets" o datos macroeconómicos. Obviamente que su núcleo duro mas desarrollado es la matemática y en ese aspecto descolla. Respecto a la Biología deja todavía mucho que desear pero no sorprende que se necesite mas tiempo para formalizar en los términos propuestos una disciplina tan empírica.
Aquí abajo les dejo la charla TED de su creador y podrán apreciar las posibilidades a futuro de este emprendimiento. A mi realmente me entusiasmó en su potencialidad.

Dejo un par de cuestiones planteadas:

¿Cómo repercutirá este tipo de desarrollos en el manejo actual de información científica via editoriales y publicaciones?

¿Estamos frente al amanecer de un nuevo perfil de investigador? ¿Buceadores de datos y creativos buscadores de patrones?

¿Ciencia con poca (o nula) infraestructura? ? ¿Se propone un tipo de trabajo científico donde países centrales y periféricos están en mejores condiciones de igualdad o todavía habrá brechas por las diferencias en la capacidad de formar capital humano?

Y por último (Para aquellos familiarizados con la obra del gran Asimov). Multivac, esa grandiosa red de información tan central en muchos de sus cuentos, fue interpretada por muchos como un adelanto visionario de lo que sería Internet. Pero ahora cuando escucho a Stephen Wolfram y las potencialidades de Wofram Alpha...bueno... tranquilamente Don Isaac prefirió saltearse uno de los mayores inventos del siglo XX para directamente escribir sobre su evolución en el siglo XXI. Por suerte, todo está por verse.


http://www.ted.com/talks/stephen_wolfram_computing_a_theory_of_everything.html

Noticias sobre Complejidad

A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus, Science

Abstract: Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six elements make up nucleic acids, proteins, and lipids and thus the bulk of living matter, it is theoretically possible that some other elements in the periodic table could serve the same functions. Here, we describe a bacterium, strain GFAJ-1 of the Halomonadaceae, isolated from Mono Lake, California, which substitutes arsenic for phosphorus to sustain its growth. Our data show evidence for arsenate in macromolecules that normally contain phosphate, most notably nucleic acids and proteins. Exchange of one of the major bioelements may have profound evolutionary and geochemical significance.

o Source: A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus, Felisa Wolfe-Simon, et al., DOI: 10.1126/science.1197258, Science Published Online, 2010/12/02

Swarm Intelligence in Animal Groups: When Can a Collective Out-Perform an Expert?, PLoS ONE

Excerpt: Using a set of simple models, we present theoretical conditions (involving group size, and diversity of individual information) under which groups should aggregate information, or follow an expert, when faced with a binary choice. We found that, in single-shot decisions, experts are almost always more accurate than the collective across a range of conditions. However, for repeated decisions - where individuals are able to consider the success of previous decision outcomes - the collective's aggregated information is almost always superior.

o Source: Swarm Intelligence in Animal Groups: When Can a Collective Out-Perform an Expert?, Katsikopoulos KV, King AJ, DOI: 10.1371/journal.pone.0015505, PLoS ONE 5(11): e15505, October 2010

Infectious Disease Modeling of Social Contagion in Networks, PLoS Comput Biol

Excerpt: Information, trends, behaviors and even health states may spread between contacts in a social network, similar to disease transmission. However, a major difference is that as well as being spread infectiously, it is possible to acquire this state spontaneously. For example, you can gain knowledge of a particular piece of information either by being told about it, or by discovering it yourself. In this paper we introduce a mathematical modeling framework that allows us to compare the dynamics of these social contagions to traditional infectious diseases. (...) As an example, we study the spread of obesity (...)

§ Source: Infectious Disease Modeling of Social Contagion in Networks, Alison L. Hill, David G. Rand, Martin A. Nowak, Nicholas A. Christakis, DOI: 10.1371/journal.pcbi.1000968, PLoS Comput Biol 6(11): e1000968, 2010/11/04

Cycling in the Complexity of Early Societies, Cliodynamics

Abstract Excerpt: Warfare is commonly viewed as a driving force of the process of aggregation of initially independent villages into larger and more complex political units that started several thousand years ago and quickly lead to the appearance of chiefdoms, states, and empires. Here we build on extensions and generalizations of Carneiro’s (1970) argument to develop a spatially explicit agent-based model of the emergence of early complex societies via warfare. (...) A general prediction of our model is continuous stochastic cycling in which the growth of individual polities in size, wealth/power, and complexity is interrupted by their quick collapse. (...)

o Source: Cycling in the Complexity of Early Societies, Gavrilets, Sergey, Anderson, David G, Turchin, Peter, Cliodynamics: The Journal of Theoretical and Mathematical History 1(1), 2010

New Clues About What Makes the Human Brain Special, Science

Excerpt: (...) researchers who've examined preserved samples of cerebral cortex from humans and several species of ape say they've found some intriguing clues about what makes the human brain unique. They report that in a particular region of the prefrontal cortex, an area that contributes to abstract thinking and other sophisticated cognition, neurons have more space between them in the human brain than in the brains of apes. This extra space allows more room for connections between neurons (...)

o Source: New Clues About What Makes the Human Brain Special, Greg Miller, DOI: 10.1126/science.330.6008.1167, Science Vol. 330 no. 6008 p. 1167, 2010/11/26

Sixteen common misconceptions about the evolution of cooperation in humans, Evolution and Human Behavior

Abstract: The occurrence of cooperation poses a problem for the biological and social sciences. However, many aspects of the biological and social science literatures on this subject have developed relatively independently, with a lack of interaction. This has led to a number of misunderstandings with regard to how natural selection operates and the conditions under which cooperation can be favoured. Our aim here is to provide an accessible overview of social evolution theory and the evolutionary work on cooperation, emphasising common misconceptions.

o Source: Sixteen common misconceptions about the evolution of cooperation in humans, West SA, Mouden CE, Gardner A, DOI: 10.1016/j.evolhumbehav.2010.08.001, Evolution and Human Behavior, in Press, November 2010

Selección del "Complexity Digest"

Irremediable Complexity?, Science

Excerpt: Many of the cell's macromolecular machines appear gratuitously complex, comprising more components than their basic functions seem to demand. How can we make sense of this complexity in the light of evolution? One possibility is a neutral ratchet-like process described more than a decade ago, subsequently called constructive neutral evolution. This model provides an explanatory counterpoint to the selectionist or adaptationist views that pervade molecular biology.

• Source: Irremediable Complexity?, Michael W. Gray, Julius Lukeš, John M. Archibald, Patrick J. Keeling, and W. Ford Doolittle, DOI: 10.1126/science.1198594, Science Vol. 330 no. 6006 pp. 920-921, 2010/11/12

Denis Dutton: A Darwinian theory of beauty, TED.com

About this talk: TED collaborates with animator Andrew Park to illustrate Denis Dutton's provocative theory on beauty -- that art, music and other beautiful things, far from being simply "in the eye of the beholder," are a core part of human nature with deep evolutionary origins.

• Source: Denis Dutton: A Darwinian theory of beauty, TED.com, 2010/11
• VIDEO - Watch this talk

Life is physics: evolution as a collective phenomenon far from equilibrium, arXiv

Excerpt: Evolution is the fundamental physical process that gives rise to biological phenomena. Yet it is widely treated as a subset of population genetics, and thus its scope is artificially limited. As a result, the key issues of how rapidly evolution occurs, and its coupling to ecology have not been satisfactorily addressed and formulated. The lack of widespread appreciation for, and understanding of, the evolutionary process has arguably retarded the development of biology as a science, with disastrous consequences for its applications to medicine, ecology and the global environment. This review focuses on evolution as a problem in non-equilibrium statistical mechanics (...)

• Source: Life is physics: evolution as a collective phenomenon far from equilibrium, Nigel Goldenfeld and Carl Woese, arXiv:1011.4125, 2010/11/18