Artículos con la etiqueta ‘población y evolución’

Beyond network structure: How heterogenous susceptibility modulates the spread of epidemics

Por • 12 mar, 2014 • Category: Ciencia y tecnología

The compartmental models used to study epidemic spreading often assume the same susceptibility for all individuals, and are therefore, agnostic about the effects that differences in susceptibility can have on epidemic spreading. Here we show that–for the SIS model–differential susceptibility can make networks more vulnerable to the spread of diseases when the correlation between a node’s degree and susceptibility are positive, and less vulnerable when this correlation is negative. Moreover, we show that networks become more likely to contain a pocket of infection when individuals are more likely to connect with others that have similar susceptibility (the network is segregated).



Inequity aversion and the evolution of cooperation

Por • 26 feb, 2014 • Category: sociologia

Evolution of cooperation is a widely studied problem in biology, social science, economics, and artificial intelligence. Most of the existing approaches that explain cooperation rely on some notion of direct or indirect reciprocity. These reciprocity based models assume agents recognize their partner and know their previous interactions, which requires advanced cognitive abilities. In this paper we are interested in developing a model that produces cooperation without requiring any explicit memory of previous game plays. Our model is based on the notion of, a concept introduced within behavioral economics, whereby individuals care about payoff equality in outcomes.



Evolution: Life has Evolved to Evolve

Por • 10 feb, 2014 • Category: Leyes

Jim Shapiro synthesizes a great many observations about the mechanisms of evolution to reach the remarkable conclusion that large-scale modification, exchange, and rearrangement of the genome are common and should be viewed as fundamental features of life. In other words, the genome should be viewed not as mostly read-only with a few rare mutations, but rather as a fully-fledged read-write library of genetic functions under continuous revision. Revision of the genome occurs during cellular replication, during multicellular development, and during evolution of a population of individuals. DNA formatting controls the timing and location of genetic rearrangements, gene expression, and genetic repair. Each of these events is under the control of precise cellular circuits. Shapiro reviews the toolbox of natural genetic engineering that provides the functionalities necessary for efficient long-term genome restructuring.



Why is combinatorial communication rare in the natural world, and why is language an exception to this trend?

Por • 14 sep, 2013 • Category: Leyes

In a combinatorial communication system, some signals consist of the combinations of other signals. Such systems are more efficient than equivalent, non-combinatorial systems, yet despite this they are rare in nature. Why? Previous explanations have focused on the adaptive limits of combinatorial communication, or on its purported cognitive difficulties, but neither of these explains the full distribution of combinatorial communication in the natural world. Here we present a nonlinear dynamical model of the emergence of combinatorial communication that, unlike previous models, considers how initially non-communicative behaviour evolves to take on a communicative function. We derive three basic principles about the emergence of combinatorial communication. We hence show that the interdependence of signals and responses places significant constraints on the historical pathways by which combinatorial signals might emerge, to the extent that anything other than the most simple form of combinatorial communication is extremely unlikely.



Evolutionary dynamics of group interactions on structured populations: A review

Por • 13 ene, 2013 • Category: sociologia

Interactions among living organisms, from bacteria colonies to human societies, are inherently more complex than interactions among particles and nonliving matter. Group interactions are a particularly important and widespread class, representative of which is the public goods game. In addition, methods of statistical physics have proven valuable for studying pattern formation, equilibrium selection, and self-organisation in evolutionary games. Here we review recent advances in the study of evolutionary dynamics of group interactions on structured populations, including lattices, complex networks and coevolutionary models. We also compare these results with those obtained on well-mixed populations. The review particularly highlights that the study of the dynamics of group interactions, like several other important equilibrium and non-equilibrium dynamical processes in biological, economical and social sciences, benefits from the synergy between statistical physics, network science and evolutionary game theory.