We analyze social dynamics in a continuous population where randomly matched individuals have to choose between two pure strategies only ('cooperate' (C) and 'not cooperate' (NC)). Individual payoffs associated to the possible outcomes of each interaction may differ across groups, depending on the specific social and cultural context to which each agent belongs. In particular, it is assumed tha...

The overwhelming success of Web 2.0, within which online social networks are key actors, has induced a paradigm shift in the nature of human interactions. The user-driven character of Web 2.0 services has allowed researchers to quantify large-scale social patterns for the first time. However, the mechanisms that determine the fate of networks at the system level are still poorly understood. For...

In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striata...

We present a dynamical theory of opinion formation that takes explicitly into account the structure of the social network in which individuals are embedded. The theory predicts the evolution of a set of opinions through the social network and establishes the existence of a martingale property, i.e. the expected weighted fraction of the population that holds a given opinion is constant in time. ...

Can evolutionary and ecological dynamics operating at one level of the biological hierarchy affect the dynamics and structure at other levels? In social insects, strong hostility towards unrelated individuals can evolve as a kin-selected counter-adaptation to intraspecific social parasitism. This aggression in turn might cause intraspecific competition to predominate over interspecific competit...

Spectrum scarcity and underutilization in wireless networks, arising due to traditional static spectrum allocation, have been of great concern since the past decade. The suboptimal use of spectrum motivates new wireless concepts where unlicensed users opportunistically access licensed spectrum using cognitive radio technology. A cognitive radio can change its operating parameter intelligently i...

introduction: heterotype pregnancy has been defined as coexistence of intrauterine and ectopic pregnancy. coexistence of intrauterine and ovarian pregnancy is rare and often occurs in women who use intra-uterine device (iud) or women under assisted reproductive technology. we report a case who presented abdominal pain and an adenexal mass in ultrasound scanning. post-operative diagnosis was coe...

Online social networks are in constant competition to attract and retain users' attention. From this point of view, OSNs and other digital services can be understood as forming a complex digital ecosystem of interacting species that compete for the same resource, our digital time. In this work, we introduce a very general and flexible framework to model such ecosystem. Akin to standard ecologic...