Identification of the local productive systems in Spain: a new approach

Paper submitted to the 44th European Congress of the European Regional Science Association, Porto, 25-29 August 2004.

An evolutive approach for the delineation of local labour markets

This paper presents a new approach to the delineation of local labour markets based on evolutionary computation. The main objective is the regionalisation of a given territory into functional regions based on commuting flows. According to the relevant literature, such regions are defined so that (a) their boundaries are rarely crossed in daily journeys to work, and (b) a high degree of intra-area movement exists. This proposal merges municipalities into functional regions by maximizing a fitness function that measures aggregate intra-region interaction under constraints of inter-region separation and minimum size. Real results are presented based on the latest database from the Census of Population in the Region of Valencia. Comparison between the results obtained through the official method which currently is most widely used (that of British Travel-to-Work Areas) and those from our approach is also presented, showing important improvements in terms of both the number of different market areas identified that meet the statistical criteria and the degree of aggregate intra-market interaction.

Exponential decay of spin-spin correlation between distant defect states produced by contour hydrogenation of polycyclic aromatic hydrocarbon molecules

The first few low-lying spin states of alternant polycyclic aromatic hydrocarbon (PAH) molecules of several shapes showing defect states induced by contour hydrogenation have been studied both by ab initio methods and by a precise numerical solution of Pariser-Parr-Pople (PPP) interacting model. In accordance with Lieb's theorem, the ground state shows a spin multiplicity equal to one for balanced molecules, and it gets larger values for imbalanced molecules (that is, when the number of π electrons on both subsets is not equal). Furthermore, we find a systematic decrease of the singlet-triplet splitting as a function of the distance between defects, regardless of whether the ground state is singlet or triplet. For example, a splitting smaller than 0.001 eV is obtained for a medium size C46H28 PAH molecule (di-hydrogenated [11]phenacene) showing a singlet ground state. We conclude that π electrons unbound by lattice defects tend to remain localized and unpaired even when long-range Coulomb interaction is taken into account. Therefore they show a biradical character (polyradical character for more than two defects) and should be studied as two or more local doublets. The implications for electron transport are potentially important since these unpaired electrons can trap traveling electrons or simply flip their spin at a very small energy cost.

A new code for the Hall-driven magnetic evolution of neutron stars

Over the past decade, the numerical modeling of the magnetic field evolution in astrophysical scenarios has become an increasingly important field. In the crystallized crust of neutron stars the evolution of the magnetic field is governed by the Hall induction equation. In this equation the relative contribution of the two terms (Hall term and Ohmic dissipation) varies depending on the local conditions of temperature and magnetic field strength. This results in the transition from the purely parabolic character of the equations to the hyperbolic regime as the magnetic Reynolds number increases, which presents severe numerical problems. Up to now, most attempts to study this problem were based on spectral methods, but they failed in representing the transition to large magnetic Reynolds numbers. We present a new code based on upwind finite differences techniques that can handle situations with arbitrary low magnetic diffusivity and it is suitable for studying the formation of sharp current sheets during the evolution. The code is thoroughly tested in different limits and used to illustrate the evolution of the crustal magnetic field in a neutron star in some representative cases. Our code, coupled to cooling codes, can be used to perform long-term simulations of the magneto-thermal evolution of neutron stars.

Acciones públicas de sensibilización de género: el esfuerzo de la administración regional y local en comunicación publicitaria (1999-2007)

El artículo analiza las iniciativas de comunicación relacionadas con la igualdad de oportunidades entre mujeres y hombres. El objetivo es analizar con enfoque de género las acciones realizadas por parte de las instituciones públicas regionales y locales para sensibilizar y promover la conciliación entre la vida familiar y laboral de seis comunidades autónomas (Andalucía, Cataluña, Comunidad Valenciana, Galicia, Madrid y País Vasco) y de sus capitales, desde 1999 (cuando se aprueba la ley de conciliación) hasta 2007 (se aprueba la ley de igualdad). La información sobre publicidad convencional fue proporcionada por Infoadex. Para la recogida de otro tipo de iniciativas a través de medios menos convencionales se acudió a cuatro fuentes institucionales: 1) Ayuntamientos de las capitales, como fuente estrictamente local, 2) Diputaciones de la capital de la Comunidad Autónoma, como fuente provincial, 3) Direcciones Generales de la Mujer o instituciones análogas como fuente de información a nivel regional o autonómico y, por último, 4) otras concejalías vinculadas al tema de la corresponsabilidad, cuyo radio de acción también es autonómico. Los resultados, aunque con diferencias entre regiones, reflejan carencias en la cobertura de las acciones que llevan a cuestionar la falta de estrategia política en términos de comunicación, pese a la introducción sistemática de estos objetivos en la agenda internacional (ONU y UE) y del gobierno español. En consecuencia, las campañas publicitarias e iniciativas recogidas contribuyen a la visibilización del problema y al empoderamiento, pero no tanto al objetivo de la paridad.