<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000'>Prezados colegas e alunos, Esta mensagem é para divulgar a palestra desta semana do ciclo de Seminários de Probabilidade e Sistemas Complexos, ICMC-USP & UFSCar, São Carlos. Uma lista das palestras passadas, e as próximas, pode ser encontrada no seguinte link: <a target="_blank" href="http://www.icmc.usp.br/pessoas/pablor/seminar/pcs_seminar.html">http://www.icmc.usp.br/pessoas/pablor/seminar/pcs_seminar.html</a> Segue a informação da próxima sexta. <h3>On Critical Phenomena and Power Laws</h3> Speaker: Thiago Mosqueiro (IFSC-USP) Date: 29/05/2015 • Time: 16h00 • Room: 4-111 (ICMC) Abstract: After heated over a certain temperature, a common refrigerator magnet looses its magnetization. This can be explained quite well investigating a set magnetic dipoles with a short-distance interaction, often studied in the form of Ising Model (and its variations). What is counter-intuitive, however, is that this behavior happens abruptly: there is a critical temperature at which the magnet's magnetization simply vanishes. Ising model shows that, at this precise temperature, the correlation between one dipole and another at some distance decays very slowly, namely with a Power Law. Thus, with an interaction involving only nearby dipoles, at the critial temperature all dipoles become somehow linked. Moreover, several important variables present unexpected behaviors, such as divergences or non-analyticity. Over the years, this has become a new area in Physics known today as Critical Phenomena, for which Kenneth Wilson, for instance, was awarded the Nobel prize in '85. Since then, this notion of criticality gained momentum, especially in systems biology. In fact, a whole new sub-area was created that seems to suit well biology and several natural phenomena: Self-Organized Criticality, where the system spontaneously evolves towards its own critical point. A decade ago, appealing observations appeared in neuroscience with evidences of a self-organized behavior working underneath several basic functions of the brain. For instance, poising the brain at the edge of two very different states may be one reason why our eyes can operate in an enormous range of light intensities. In this talk I review some recent papers on this subject and present timely gaps in the current literature from a point of view of Dynamical Systems and Stochastic Processes. In special, I will focus on the actual role of Power Laws in these observations and a possible biases in recent investigations that do not only apply to neuroscience, but any experimental research on criticality. My main objective, then, is to present problems where contributions from modeling Stochastic Processes would have a significantly impact and may contribute to the understanding of the brain. Estão todos convidados! Favor divulgar a possíveis interessados. Um abraço, Pablo Rodriguez </div></body></html>