Despite many efforts crises on financial markets are in large part still scientific black-boxes. In this paper, we use a winner-take-all approach to construct a longitudinal network of S&P 500 companies and their correlations between 2000 and 2012. A comparison to complex ecosystems is drawn,...

We show that the fluctuations of a variety of animal (insect, mammal and fish) populations are well-modeled by stable (Lévy) distributions, a family of distributions which includes the Gaussian. Our findings together with the finding [A.P. Allen, B.-L. Li, E.L. Charnov, Ecol. Lett. 4 (2001)...

We consider a mathematical model of eradication by competition between wild and sterile species when immigration is present. We discuss the case with constant and random immigration flux. In the first case, there is a threshold of eradication Mc related to the number M of sterile individuals....

Many species of ants engage in social foraging in which traffic develops over pathways defined by pheromones or physical roads cleared through debris. Worker ants from the same colony have a common underlying evolutionary interest in their collective performance. Thus, ant traffic makes an...

Starting from the well-known field theory for directed percolation (DP), we describe an evolving population, near extinction, in an environment with its own nontrivial spatio-temporal dynamics. Here, we consider the special case where the environment follows a simple relaxational (Model A)...