Formación del anillo de crecimiento y clima: un ejemplo de modelos para Pinus uncinata Ram. y Pinus sylvestris L. en los Pirineos Centrales

En este trabajo, describimos el desarrollo y la estructura del anillo de crecimiento de Pinus uncinata Ram. y de Pinus sylvestris L. en un gradiente altitudinal en los Pirineos centralese

Caracterització hidràulica i energètica de dues bombes helicoïdals i una comporta antiretorn

Els dispositius objectes d'aquest estudi són una comporta autoretorn de pas total i tres bombes helicoïdals (un prototipus de bomba cònica, una bomba cilíndrica fixa i un prototipus de bomba cilíndrica de nivell variable). L'objectiu del document és l'avaluació hidràulica i energètica de les bombes helicoïdals i la comporta, a més de la realització d'una modelització dels quatre dispositius. D'altra banda, en el treball s'indiquen algunes propostes de millora pel disseny actual dels prototipus de bombes helicoïdals estudiades.

Sense títol

Postprint (published version)

Potential of local bio-geoengineering to mitigate dangerous temperature increases in a global warming scenario

Crops and forests are already responding to rising atmospheric carbon dioxide and air temperatures. Increasing atmospheric CO2 concentrations are expected to enhance plant photosynthesis. Nevertheless, after long-term exposure, plants acclimate and show a reduction in photosynthetic activity (i.e. down-regulation). If in the future the Earth"s temperature is allowed to rise further, plant ecosystems and food security will both face significant threats. The scientific community has recognized that an increase in global temperatures should remain below 2°C in order to combat climate change. All this evidence suggests that, in parallel with reductions in CO2 emissions, a more direct approach to mitigate global warming should be considered. We propose here that global warming could be partially mitigated directly through local bio-geoengineering approaches. For example, this could be done through the management of solar radiation at surface level, i.e. by increasing global albedo. Such an effect has been documented in the south-eastern part of Spain, where a significant surface air temperature trend of -0.3°C per decade has been observed due to a dramatic expansion of greenhouse horticulture.

Gestor web de una entidad deportiva

El proyecto consiste en el diseño y desarrollo de una aplicación web para la gestión de una entidad deportiva. La aplicación ha de permitir la gestión de las distintas facetas deportivas: temporadas, categorías, ligas, equipos, resultados y clasi caciones. También será un escaparate de lo que ocurre en la entidad para socios y accionados; así, también ha de servir para la publicación de noticias relacionadas con la entidad y facilitar la información en una zona pública que podrá ver cualquiera.

From Master Plan to punctual interventions. Slums in Barcelona

The sloppy process of urbanization that took place in the outskirts of Barcelona from mid XIXth to mid XXth century resulted on large informal slums with evident urban deficiencies. The Metropolitan Masterplan of 1976 and its subsequent amendments could only partially improve the conditions of these areas of the city. Since 2005 some initiatives, in which local community or academic research played an important role, were undertaken following a tactical approach. The paper summarizes six proposed strategies that are a reaction to the traditional planning and zoning approach for the area. Some of them are currently been discussed or have already been included in the planning framework of the city.

La demanda de professionals en l'àmbit de la gestió i l'administració. Què volen les empreses?

Ajuts a la Recerca en Docència Universitària de l'Institut de Ciències de l'Educacuó de la Universitat de Barcelona REDICE-ACCIÓ-13

Monte Carlo study of a kinetic lattice model with random diffusion of disorder

We report Monte Carlo results for a nonequilibrium Ising-like model in two and three dimensions. Nearest-neighbor interactions J change sign randomly with time due to competing kinetics. There follows a fast and random, i.e., spin-configuration-independent diffusion of Js, of the kind that takes place in dilute metallic alloys when magnetic ions diffuse. The system exhibits steady states of the ferromagnetic (antiferromagnetic) type when the probability p that J>0 is large (small) enough. No counterpart to the freezing phenomena found in quenched spin glasses occurs. We compare our results with existing mean-field and exact ones, and obtain information about critical behavior.

Reaction-diffusion lattice gas: Theory and computer results

We report on the study of nonequilibrium ordering in the reaction-diffusion lattice gas. It is a kinetic model that relaxes towards steady states under the simultaneous competition of a thermally activated creation-annihilation $(reaction$) process at temperature T, and a diffusion process driven by a heat bath at temperature T?T. The phase diagram as one varies T and T, the system dimension d, the relative priori probabilities for the two processes, and their dynamical rates is investigated. We compare mean-field theory, new Monte Carlo data, and known exact results for some limiting cases. In particular, no evidence of Landau critical behavior is found numerically when d=2 for Metropolis rates but Onsager critical points and a variety of first-order phase transitions.

Ising critical behavior of a non-Halmiltonian lattice system

We study steady states in d-dimensional lattice systems that evolve in time by a probabilistic majority rule, which corresponds to the zero-temperature limit of a system with conflicting dynamics. The rule satisfies detailed balance for d=1 but not for d>1. We find numerically nonequilibrium critical points of the Ising class for d=2 and 3.