22,628 research outputs found
Thermostatistics of extensive and non-extensive systems using generalized entropies
We describe in detail two numerical simulation methods valid to study systems
whose thermostatistics is described by generalized entropies, such as Tsallis.
The methods are useful for applications to non-trivial interacting systems with
a large number of degrees of freedom, and both short-range and long-range
interactions. The first method is quite general and it is based on the
numerical evaluation of the density of states with a given energy. The second
method is more specific for Tsallis thermostatistics and it is based on a
standard Monte Carlo Metropolis algorithm along with a numerical integration
procedure. We show here that both methods are robust and efficient. We present
results of the application of the methods to the one-dimensional Ising model
both in a short-range case and in a long-range (non-extensive) case. We show
that the thermodynamic potentials for different values of the system size N and
different values of the non-extensivity parameter q can be described by scaling
relations which are an extension of the ones holding for the Boltzmann-Gibbs
statistics (q=1). Finally, we discuss the differences in using standard or
non-standard mean value definitions in the Tsallis thermostatistics formalism
and present a microcanonical ensemble calculation approach of the averages.Comment: Submitted to Physica A. LaTeX format, 38 pages, 17 EPS figures.
IMEDEA-UIB, 07071 Palma de Mallorca, Spain, http://www.imedea.uib.e
Explaining inflation and output volatility in Chile : an empirical analysis of forty years
We present a data oriented analysis of the effect of different kind of economic shocks on Chilean output growth and inflation over the last 40 years. Two important results are: (1) foreign shocks only explain 17% of the variability of the output growth in the period 1984-2006 whereas it used to account for the 47,2% of output variability in 1966-1983; (2) The participation of foreign shocks to explain the Chilean inflation reaction becomes more importan in the last twienty years because of the price liberalization and Chile's openness to international trade. Results highlight specific features of the Chilean economy not present in other countries.
Energy and number of collisions fluctuations in inelastic gases
We study by numerical simulations the two-dimensional Inelastic Maxwell Model
(IMM), and show how the inelasticity of collisions together with the
fluctuations of the number of collisions undergone by a particle lead to energy
fluctuations that decay like a power-law. These fluctuations are associated to
a shrinking of the available phase space. We find the asymptotic scaling of
these energy fluctuations and show how they affect the tail of the velocity
distribution during long time intervals.Comment: 4 pages, 3 figure
El desarrollo de la energía nuclear y los riesgos de proliferación: el caso de Irán
El programa nuclear civil y militar de Irán muestra cómo ha progresado la proliferación nuclear apoyada en la demanda de energía, en la transferencia de tecnologías críticas y en la debilidad del régimen de no proliferación
En los últimos años se ha producido un creciente interés en la energía nuclear como fuente de suministro y de diversificación de los recursos energéticos. La técnica de producción del combustible nuclear permite acabar produciendo material fisible militar. La dualidad de la tecnología nuclear supone un desafío estratégico y los procesos de proliferación nuclear han alterado el contexto estratégico de la península coreana, Asia Meridional y Oriente Medio. Los intentos de limitar la proliferación nuclear tratan de preservar el equilibrio adecuado entre los tres pilares del Tratado de No Proliferación de Armas Nucleares –desarme nuclear, no proliferación y usos pacíficos de la energía nuclear–, pero con escaso éxito, como demuestra el caso iraní que se describe en este ARI
Efectividad de intervenciones en promoción de la salud y salud pública: Lecciones de casos latinoamericanos
The issue of evidence of effectiveness in public health and health promotion has occupied the attention of academics,
technicians, and politicians who recognize not only its importance but the challenges that researchers must confront to obtain
reliable and useful information to base public policy decisions and investment of resources. Despite the emergence of Latin
American initiatives aimed at building the capacity to obtain such evidence of effectiveness, the practice is still incipient in
the region and there are few relevant publications. This article is presented as a contribution and stimulus to further motivate
the ongoing search for information and knowledge, concerning the relevance and scope of the practice of public health and
health promotion to address adverse health conditions. For this purpose, a review of the literature was carried out, along with
the compilation, documentation, and analysis of various cases of Latin American evaluations. From the product of this analysis,
proposals are presented for strengthening the theoretical and evaluative practices in Latin America. El tema de evidencias de efectividad en promoción de la salud y salud pública ha ocupado la atención de académicos,
técnicos y políticos, quienes reconocen no sólo su importancia, sino los desafíos que hay que enfrentar para obtener
información confiable y útil que fundamente decisiones en política pública e inversión de recursos. Pese a diversas iniciativas
latinoamericanas orientadas a la construcción de capacidad para obtener dichas evidencias de efectividad, esta práctica es
aún incipiente en la región y son escasas las publicaciones al respecto. Este artículo surge como una contribución y una
provocación para motivar la búsqueda permanente de información y conocimiento sobre la pertinencia y alcance de la práctica
de la salud pública y la promoción de la salud, la comprensión de los procesos de implementación de las políticas y programas
y la valoración de los resultados. Para esto, se ha realizado una revisión de literatura, así como recopilación, documentación
y análisis de diversos casos de evaluación latinoamericanos. Como producto del análisis se presentan propuestas para el
fortalecimiento de la teoría y la práctica evaluativa en Latinoamérica
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