The Cerdà year and our fixation on origins

Peer Reviewe

Very large stochastic resonance gains in finite sets of interacting identical subsystems driven by subthreshold rectangular pulses

We study the phenomenon of nonlinear stochastic resonance (SR) in a complex noisy system formed by a finite number of interacting subunits driven by rectangular pulsed time periodic forces. We find that very large SR gains are obtained for subthreshold driving forces with frequencies much larger than the values observed in simpler one-dimensional systems. These effects are explained using simple considerations.Comment: 4 pages, 5 figures. to appear in Phys. Rev.

System size stochastic resonance in driven finite arrays of coupled bistable elements

The global response to weak time periodic forces of an array of noisy, coupled nonlinear systems might show a nonmonotonic dependence on the number of units in the array. This effect has been termed system size stochastic resonance. In this paper, we analyze the nonmonotonic dependence on the system size of the signal-to-noise ratio of a collective variable characterizing a finite array of one-dimensional globally coupled bistable elements. By contrast with the conventional nonmonotonic dependence with the strength of the noise (stochastic resonance), system size stochastic resonance is found to be restricted to some regions in parameter space

Las transiciones de la formación al trabajo de los jóvenes españoles en el marco de las medidas educativas contempladas en la Estrategia de Emprendimiento y Empleo Joven 2013-2016

Este trabajo aborda el estudio de algunas de las medidas de carácter formativo incluidas en la “Estrategia de Emprendimiento y Empleo Joven 2013-16” que el Gobierno de España ha diseñado para combatir el desempleo juvenil, el abandono escolar temprano y la insu? ciente cuali?cación profesional que caracteriza a los jóvenes españoles menores de 30 años. La importancia de contar con una formación y cuali?cación profesional sólida es hoy día un requisito básico para tener éxito en el mercado laboral y , por ello, un tercio de las cien medidas propuestas en esta estrategia se basan en el desarrollo de iniciativas que posibiliten la adquisición de una mayor empleabilidad en los jóvenes que se encuentran, actualmente, fuera del mercado de trabajo. Destacan entre las medidas propuestas a corto plazo las dirigidas a fomentar trestiposde programas:los dirigidos a la obtención de certi?cados de profesionalidad; los que implican formación con compromiso de contratación y los programas que facilitan la adquisición del título de educación secundaria obligatoria a los jóvenes que abandonaron prematuramente sus estudios. Para comprender el alcance de estas propuestas es necesario realizar un análisis del proceso que se ha ido produciendo en el Sistema Educativo Español para acomodarse a la estructura socio-laboral de la UniónEuropea y las implicacionesque tiene para los ciudadanos.This report deals with the study ofsome of the measures of educational character, included in the “Strategy of Entrepreneurship and Youth Employment 2013-16”, in which the government of Spain has designed to combatyouth unemployment, early s chool leaving and insuf?cient professional quali? cation that characterizes young Spanish people under the age of 30 years old. The importance of counting on training and professional quali? cation is now a basic requirement to succeed in the labour market and therefore a third of the one hundred measures proposed in this strategy isbased on developing initiatives that allow the acquisition of greater employability in youth who are currently outside the labor market. Prominent among the proposed short-term measures are three types of programs, those aimed at obtaining professional certi?cates, traininginvolving the commitment of hiring, and programs that facilitate the acquisition of the title of compulsory secondary education amongst youth that leave their studies prematurely. To understand the scope of these proposals it is necessary to perform an analysis of the processthat has taken place in the Spanish educational system to suit the structure ofsocial-labour of the European Union and the implications on citizens

Theory of frequency and phase synchronization in a rocked bistable stochastic system

We investigate the role of noise in the phenomenon of stochastic synchronization of switching events in a rocked, overdamped bistable potential driven by white Gaussian noise, the archetype description of Stochastic Resonance. We present a new approach to the stochastic counting process of noise-induced switching events: starting from the Markovian dynamics of the nonstationary, continuous particle dynamics one finds upon contraction onto two states a non-Markovian renewal dynamics. The output frequency is determined as the velocity of the underlying discrete phase dynamics. The phenomenon of noise-assisted phase synchronization is investigated in terms of an effective, instantaneous phase diffusion. The theory is applied to rectangular-shaped rocking signals versus increasing input-noise strengths. Precise numerical simulations corroborate very favorably our analytical results. The novel theoretical findings are also compared with prior findings.Comment: 14 pages, 4 figure

Noise-induced forced synchronization of global variables in coupled bistable systems

We analyze the noise-induced synchronization between a collective variable characterizing a complex system with a finite number of interacting bistable units and time-periodic driving forces. A random phase process associated to the collective stochastic variable is defined. Its average phase frequency and average phase diffusion are used to characterize the phenomenon. Our analysis is based on numerical solutions of the corresponding set of Langevin equations.Ministerio de Educación y Ciencia FIS2005-0288

Ríos de ideas

Un viaje a Santiago del autor entrega una experiencia de recorrido de la ciudad y del río Mapocho, que muchas veces no somos capaces de ver y comprender. La existencia de una particular topografía y del cauce del río son determinantes de un paisaje, una trama urbana compleja y de situaciones particulares que enriquecen la ciudad.An author’s trip to Santiago offers an experience of the city’s and Mapocho River’s promenade, which we are often not able to see and understand. The existence of a particular topography and a river bed are the determinants of landscape, a complex urban scheme, and the particular situations that enrich the city

Agua y territorio

I Congreso Andaluz de Desarrollo Sostenible – V Congreso Andaluz de Ciencias Ambientale

Nonlinear Stochastic Resonance with subthreshold rectangular pulses

We analyze the phenomenon of nonlinear stochastic resonance (SR) in noisy bistable systems driven by pulsed time periodic forces. The driving force contains, within each period, two pulses of equal constant amplitude and duration but opposite signs. Each pulse starts every half-period and its duration is varied. For subthreshold amplitudes, we study the dependence of the output signal-to-noise ratio (SNR) and the SR gain on the noise strength and the relative duration of the pulses. We find that the SR gains can reach values larger than unity, with maximum values showing a nonmonotonic dependence on the duration of the pulses.Comment: 7 pages, 2 figure

Feshbach-like study of He resonant states in Debye plasmas using explicitly correlated wave functions

ABSTRACT: We present a study on the 1;3Se, 1;3Po and 1;3De He resonant states below the He+ (N=2) threshold under the in uence of a plasma environment, when the Debye screening length is varied. The interaction between all charged particles is modeled with Yukawa-like screened Coulomb potentials. We make use of the Feshbach projector method to characterize resonant states, implemented by using explicitly correlated CI-wave functions