There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

N G van Kampen 1981 Amsterdam: North-Holland xiv + 419 pp price Dfl 180 This is a book which, at a lower price, could be expected to become an essential part of the library of every physical scientist concerned with problems involving fluctuations and stochastic processes, as well as those who just enjoy a beautifully written book. It provides an extensive graduate-level introduction which is clear, cautious, interesting and readable.

https://iopscience.iop.org/article/10.1088/0031-9112/34/4/040/pdf

Stochastic Processes in Physics and Chemistry

In the Hamadryas baboon, males are substantially larger than females. A troop of baboons is subdivided into a number of ‘one-male groups’, consisting of one adult male and one or more females with their young. The male prevents any of ‘his’ females from moving too far from him. Kummer (1971) performed the following experiment. Two males, A and B, previously unknown to each other, were placed in a large enclosure. Male A was free to move about the enclosure, but male B was shut in a small cage, from which he could observe A but not interfere. A female, unknown to both males, was then placed in the enclosure. Within 20 minutes male A had persuaded the female to accept his ownership. Male B was then released into the open enclosure. Instead of challenging male A , B avoided any contact, accepting A’s ownership.

Evolution and the Theory of Games

Stable non-Gaussian random processes , by G. Samorodnitsky and M. S. Taqqu. Pp. 632. £49.50. 1994. ISBN 0-412-05171-0 (Chapman and Hall).

Fil: Nicolas, Alexandre. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Centre National de la Recherche Scientifique; Francia

Pedestrian flows through a narrow doorway: Effect of individual behaviours on the global flow and microscopic dynamics

We study the role of potential symmetry in a three-field reaction-diffusion system presenting bistability by means of a two-state theory for stochastic resonance in general asymmetric systems. By analyzing the influence of different parameters in the optimization of the signal-to-noise ratio, we observe that this magnitude always increases with the symmetry of the system's potential, indicating that it is this feature which governs the optimization of the system's response to periodic signals.

Stochastic resonance in extended bistable systems: the role of potential symmetry.

Within the two state theory (TST) for stochastic resonance (SR) we analize two different aspects: (a) the extension of the TST in order to include potential asymmetry (i.e.: the states show different stabilities); (b) the evaluation of transition rates for systems whose stationary distribution is non Gaussian. We apply the results of (a) to study the role of the potential symmetry for SR in bistable systems, observing that the signal-to-noise ratio increases with the symmetry of the potential of the system indicating that it is this feature that governs the optimization of the response. We apply the results of (b) to discuss SR in situations where we can assume that the noise is non Gaussian, and discuss its relation with experimental results in sensory systems.

/pdf/stochastic-resonance-the-role-of-potential-asymmetry-and-non-13gp4xpukd.pdf

Stochastic resonance: the role of potential asymmetry and non Gaussian noises

We analyze the pedestrian evacuation of a rectangular room with a single door considering a lattice gas scheme with the addition of behavioral aspects of the pedestrians. The movement of the individuals is based on random and rational choices and is affected by conflicts between two or more agents that want to advance to the same position. Such conflicts are solved according to certain rules closely related to the concept of strategies in game theory, cooperation and defection. We consider game rules analogous to those from the Prisoner's Dilemma and Stag Hunt games, with payoffs associated to the probabilities of the individuals to advance to the selected site. We find that, even when defecting is the rational choice for any agent, under certain conditions, cooperators can take advantage from mutual cooperation and leave the room more rapidly than defectors. Language: en

Game theory in models of pedestrian room evacuation

Recent studies on Brownian motors driven by colored non-Gaussian noises have shown that the departure of the noise distribution from Gaussian behavior induces an enhancement of its current and efficiency. Here, we discuss some new aspects of this phenomenon focusing on some analytical results based on an adiabatic approximation and in the analysis of the role of long probability distribution tails.

/pdf/new-aspects-on-current-enhancement-in-brownian-motors-driven-4uup4o85d5.pdf

Sebastián Bouzat

Papers

Pedestrian flows through a narrow doorway: Effect of individual behaviours on the global flow and microscopic dynamics

Stochastic resonance in extended bistable systems: the role of potential symmetry.

Stochastic resonance: the role of potential asymmetry and non Gaussian noises

Game theory in models of pedestrian room evacuation

New aspects on current enhancement in Brownian motors driven by non-Gaussian noises