Events

  • Seminar: Complexitat en evolució humana

    Speaker
    Eudald Carbonell

    Description En la seva intervenció, Carbonell es remuntarà als orígens dels primers homínids, quan fa 3,6 milions d’anys van començar a elaborar les primeres eines de pedra, a l’Àfrica, fruit de la confluència de diversos factors que van posar en marxa una sèrie de sistemes complexos que han acompanyat la història de l’evolució humana. Concretament, l’investigador de l’IPHES se centrarà en el paper fonamental que en aquest procés ha tingut la tecnologia. Per aquest motiu es referirà a seva emergència i a alguns conceptes claus com la homogeneïtat, la diversitat i la multiplicitat.

  • Search and Stochastic Processes in Complex Physical and Biological Systems

    Description

    The goal of the workshop is to bring together leading scientists to discuss recent theoretical and experimental progress in studies of search processes, and to advance the synergies between the communities working in condensed matter and statistical physics, quantitative biology, and mathematics.

    Organizers
    Carlos Mejia-Monasterio Raul Toral Horacio Wio

  • Seminar: Spatio-temporal organization of emergent activity in the cerebral cortex

    Speaker
    M.V. Sánchez-Vives

    Description Understanding complex systems like brain networks is a challenge. Cortical networks can perform computations of remarkable complexity, accounting for a large variety of behaviours and cognitive states. At the same time, the same networks can engage in stereotypical patterns of spatio-temporal activation, such as the ones that can be observed during sleep, anaesthesia and in cortical slices [1]. Collective phenomena emerging from activity reverberation in cortical circuits at different spatio-temporal scales results in a rich variety of dynamical states. Slow (around or below 1 Hz) and fast (15-100 Hz) rhythms are spontaneously generated by the cortical network and propagate or synchonize populations across the cortex [2]. This is the case even in isolated pieces of the cortical network, or in vitro maintained cortical slices, where both slow [3] and fast oscillations [4] are also spontaneously generated. Interestingly, cortical slices lack any inputs from other brain areas, thus representing what the recurrency within the isolated cortical network can autonomously generate. The similarity between some of these patterns both in vivo and in vitro suggests that they are somehow a default activity from the cortical network. We understand that these emergent patterns provide information on the structure, dynamics and function of the underlying cortical network. In this talk I will discuss what we do know and what some of the challenges that we are facing in order to understand cortical dynamics. 1. Steriade, M., The corticothalamic system in sleep. Front Biosci, 2003. 8: p. d878-99. 2. Massimini, M., et al., The sleep slow oscillation as a traveling wave. J Neurosci., 2004. 24(31): p. 6862-6870. 3. Sanchez-Vives, M.V. and D.A. McCormick, Cellular and network mechanisms of rhythmic recurrent activity in neocortex. Nat Neurosci, 2000. 3(10): p. 1027-34. 4. Compte, A., et al., Spontaneous high-frequency (10-80 Hz) oscillations during up states in the cerebral cortex in vitro. J Neurosci, 2008. 28(51): p. 13828-44.

  • Seminar: Un saludo a todos

    Speaker
    Marisela Vélez

  • Seminar: Research at the interface between physical and life sciences: epidemics and environment

    Speaker
    F.J. Pérez-Reche

    Description Statistical physics has traditionally dealt with complex physical systems and it is increasingly being recognised as a powerful framework to deal with biological systems. In this seminar, I will present examples in which an interdisciplinary research at the interfaces physics/epidemiology and physics/environment proves useful. One of the main questions in epidemiology regards the outbreak of epidemics, i.e. whether an infectious disease can spread throughout a given ensemble of hosts or not. Similar questions are addressed in ecology and sociology which deal with the spread of agents such as behaviour or opinion in populations of animals. The challenge lies in dealing with factors such as heterogeneity, stochasticity, and behavioural trends associated with both the spreading agent and the population of hosts [1-5]. I will start with a survey of experimental results illustrating each of these factors at the host level and for small populations. I will then propose mathematical models inspired from statistical physics whose main aims are to (i) link the factors at the host level to the probability of invasion at the population level, (ii) devise control strategies for invasion, and (iii) predict invasion from the early stage of an epidemic. As an illustration of the interplay physics/environment, I will consider the environmental role played by the biological processes in soil. Understanding the factors that influence the soil microbial activity is important but highly challenging due to the opacity of soil and the difficulty of interfering with soil microorganisms in a controlled manner. We have recently proposed a framework that shows that the structural heterogeneity of the soil habitatmay have a very significant influence on the size of microbial invasions of the soil pore space [6]. Our approach uses a network representation of real soil samples (see figure) to build mathematical models for microbial spread.