Search results for "libri"

Self-regulation mechanism of an ecosystem in a non-Gaussian fluctuation regime

1996

We study a dynamical model for an ecological network of many interacting species. We consider a Malthus-Verhulst type of self-regulation mechanism. In the framework of the mean field theory we study the nonlinear relaxation in three different cases: (a) towards the equilibrium state, (b) towards the absorbing barrier, (c) at the critical point. We obtain asymptotic behavior in all different cases for the time average of the process. The dynamical behavior of the system, in the limit of infinitely many interacting species, is investigated in the stability and instability conditions and theoretical results are compared with numerical simulations. \textcopyright{} 1996 The American Physical So…

Influencia de la tarea dual y la restricción sensorial sobre el control postural en los adolescentes de 13 a 18 años

2020

El presente proyecto tiene como principal objetivo analizar la influencia de la maduración, de las tareas duales y de la restricción de información sensorial en el control postural de los adolescentes. Para ello se han diseñado tres estudios diferentes con una muestra compuesta por adolescentes de entre 13 a 18 años. En el estudio 1 se pretende analizar las diferencias en la estabilidad postural unipodal en función del sexo y la edad de los adolescentes de 13 a 18 años. Los resultados obtenidos muestran unos valores más elevados en las variables área de la elipse, velocidad media antero-posterior y medio-lateral en los chicos que en las chicas. Además, los adolescentes de 14 años muestran u…

DEVELOPMENT OF A TEST FOR EVALUATING THE CONCEPTUAL KNOWLEDGE OF CHEMICAL EQUILIBRIUM CONSTANT AMONG UNIVERSITY STUDENTS AND ITS APPLICATION TO SPANI…

2014

This article outlines a procedure that was used to develop a written test for evaluating the conceptual knowledge of chemical equilibrium constant among university students. The concepts in the subject matter were carefully defined through propositional statements. Students' understanding of the topic was determined through interviews. These data were used to produce nine multiple choice questions. Each question was designed to identify misconceptions related to the chemical equilibrium constant. The test was evaluated by foure associate professors and was administred to a total of 196 spanish university students. This test has a Cronbach's alpha reliability of 0.63 and its content validity…

Quasiparticle properties of nonequilibrium gluon plasma

2018

We apply classical gluodynamics to early stages of ultrarelativistic heavy-ion collisions. We start by giving a brief overview of QCD. Then we proceed to the space-time evolution of ultrarelativistic heavy-ion collisions in the color glass condensate framework and go through the basics of real-time gluodynamics on the lattice in the temporal gauge. We study the plasmon mass scale in three- and two-dimensional systems by comparing three different methods to measure the mass scale. The methods are a formula which can be derived from Hard Thermal Loop effective theory at leading order (HTL), the effective dispersion relation (DR) and measurement of the plasma oscillation frequency triggered by th…

Environmental Effects on Mechanical, Thermophysical and Electrical Properties of Epoxy Resin Filled with Carbon Nanofillers

2019

The aim of this work was to establish the effect of environmental factors (moisture and temperature) on some mechanical, electrical and thermal properties of epoxy-based composites filled with carbon nanofillers: nanotubes (CNT), nanofibers (CNF) and hybrid nanofiller (nanotubes/nanofibers in the ratio 1:1) and to reveal the most environmentally stable NC. First, the nanocomposites (NC) containing different nanofiller contents were prepared to evaluate electrical percolation threshold and to choose NC at certain electrical conductivity for further characterization of the physical properties in initial state and during/after environmental ageing. The environmental ageing consisted of water a…

La variabilenell'applicazione del metodo dell'EQUILIBRIO FONATORIO

2009

Volumes of aqueous block copolymers based on poly(propylene oxides) and poly(ethylene oxides) in a large temperature range: A quantitative description

2006

The focus of this paper was on a quantitative comprehension of temperature effect on the volumes of aqueous di-block and triblock copolymers, based on propylene oxide (PO) and ethylene oxide (EO) units. To this purpose, literature data dealing with (EO316PO94 + water) and (EO13PO30EO13 + water) mixtures were analyzed. The volume vs. temperature trends were rationalized on the basis of the (unimers + aggregate) equilibrium by taking into account the temperature effect on both the partial molar volumes of the unimeric and the aggregated copolymer as well as the equilibrium constant of micellization. The analysis extended to the expansibility allowed to quantify the contribution for the shift …

Anticipatory Postural Adjustments and kinematic arm features when postural stability is manipulated

2018

International audience; Beyond the classical paradigm that presents the Anticipatory Postural Adjustments (APAs) as a manner to create forces that counteract disturbances arising from the moving segment during a pointing task, there is a controversial discussion about the role APAs to facilitate the movement and perform a task accurately. In addition, arm kinematics features are classically used to infer the content of motor planning for the execution and the control of arm movements, The present study aimed to disentangle the conflicting role of APAs during an arm-pointing task in which the subjects reach a central diode that suddenly turns on, while their postural stability was manipulate…

Les limites de la théorie du salaire d'efficience

1998

Efficiency wage theory, evolved by the "new keynesians", is part of a research programme concerned with explaining "involuntary" unemployment as part of the "general equilibrium". So, these works are a synthesis attempt of neo-classical and keynesian analyses in the employment area. Indeed, the authors place their analysis in a walrasian framework, but they integrate a keynesian concept to complete their models. In order to achieve their purpose, the efficiency wage theorists formulate two propositions on which their argument is based: 1° the relation supposed rising between the rate of wage and the productivity of wage earners, 2° the determination of the rate of wage outside the market. W…