An Approach to Publish Spatial Data on the Web: The GeoLinked Data Case

In this paper we report on an ongoing process aimed at publishing hydrographical data on the Web with a Spanish GeoLinked Data Use Case. Moreover, we discuss the process we followed, and propose methodological guidelines for all the activities involved within the process

Einstein-Maxwell-scalar black holes: the hot, the cold and the bald

The phenomenon of spontaneous scalarisation of charged black holes (BHs) has recently motivated studies of various Einstein-Maxwell-scalar models. Within these models, different classes of BH solutions are possible, depending on the non-minimal coupling function $f(\phi)$, between the scalar field and the Maxwell invariant. Here we consider the class wherein both the (bald) electrovacuum Reissner-Nordstr\"om (RN) BH and new scalarised BHs co-exist, and the former are never unstable against scalar perturbations. In particular we examine the model, within this subclass, with a quartic coupling function: $f(\Phi) = 1+\alpha \Phi ^4$. The domain of existence of the scalarised BHs, for fixed $\alpha$, is composed of two branches. The first branch (cold scalarised BHs) is continuously connected to the extremal RN BH. The second branch (hot scalarised BHs) connects to the first one at the minimum value of the charge to mass ratio and it includes overcharged BHs. We then assess the perturbative stability of the scalarised solutions, focusing on spherical perturbations. On the one hand, cold scalarised BHs are shown to be unstable by explicitly computing growing modes. The instability is quenched at both endpoints of the first branch. On the other hand, hot scalarised BHs are shown to be stable by using the S-deformation method. Thus, in the spherical sector this model possesses two stable BH local ground states (RN and hot scalarised). We point out that the branch structure of BHs in this model parallels the one of BHs in five dimensional vacuum gravity, with [Myer-Perry BHs, fat rings, thin rings] playing the role of [RN, cold scalarised, hot scalarised] BHs.Comment: 12 pages, 6 figure

Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy

The study of stellar populations in early-type galaxies in different environments is a powerful tool for constraining their star formation histories. This study has been traditionally restricted to the optical range, where dwarfs around the turn-off and stars at the base of the RGB dominate the integrated light at all ages. The near-infrared spectral range is especially interesting since in the presence of an intermediate-age population, AGB stars are the main contributors. In this letter, we measure the near-infrared indices NaI and D$_{\rm CO}$ for a sample of 12 early-type galaxies in low density environments and compare them with the Fornax galaxy sample presented by Silva et al. (2008). The analysis of these indices in combination with Lick/IDS indices in the optical range reveals i) the NaI index is a metallicity indicator as good as C4668 in the optical range, and ii) D$_{\rm CO}$ is a tracer of intermediate-age stellar populations. We find that low-mass galaxies in low density environments show higher NaI and D$_{\rm CO}$ than those located in Fornax cluster, which points towards a late stage of star formation for the galaxies in less dense environments, in agreement with results from other studies using independent methods.Comment: 7 pages, 3 figures, accepted for publication in ApJ

On the Environmental Dependence of Cluster Galaxy Assembly Timescale

We present estimates of CN and Mg overabundances with respect to Fe for early-type galaxies in 8 clusters over a range of richness and morphology. Spectra were taken from the Sloan Digital Sky Survey (SDSS) DR1, and from WHT and CAHA observations. Abundances were derived from absorption lines and single burst population models, by comparing galaxy spectra with appropriately broadened synthetic model spectra. We detect correlations between [Mg/CN] and [CN/Fe] and cluster X-ray luminosity. No correlation is observed for [Mg/Fe]. We also see a clear trend with the richness and morphology of the clusters. This is interpreted given varying formation timescales for CN, Mg and Fe, and a varying star formation history in early-type galaxies as a function of their environment: intermediate-mass early-type galaxies in more massive clusters are assembled on shorter timescales than in less massive clusters, with an upper limit of ~1 Gyr.Comment: Accepted for publication in ApJ Letter

Stress analysis of finite anisotropic plates with cutouts under displacement boundary conditions

XI CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Móstoles los días 6, 7 y 8 de julio de 2015The aim of this article is to provide an analytical tool to estímate the stress concentration in anisotropic plates weakened by a circular or elliptical hole; it is achieved by developing Lekhnitskii formalism in order to allow fínite boundary effects to be added (original formulation considers infinite plates). Only membrane problem is herein considered, particularly when prescribed displacements are applied at externa! boundaries, which could simulate boundary conditions of a manhole structure between wing spars. A boundary collocation method in conjunction with a least squares approach is used to solve the problem.Ministerio de Economía y Competitividad de España DPT2012-3718

Biological applications of ferroelectric materials

The study and applications of ferroelectric materials in the biomedical and biotechnological fields is a novel and very promising scientific area that spans roughly one decade. However, some groups have already provided experimental proof of very interesting biological modulation when living systems are exposed to different ferroelectrics and excitation mechanisms. These materials should offer several advantages in the field of bioelectricity, such as no need of an external electric power source or circuits, scalable size of the electroactive regions, flexible and reconfigurable “virtual electrodes,” or fully proved biocompatibility. In this focused review, we provide the underlying physics of ferroelectric activity and a recount of the research reports already published, along with some tentative biophysical mechanisms that can explain the observed results. More specifically, we focus on the biological actions of domain ferroelectrics and ferroelectrics excited by the bulk photovoltaic effect or the pyroelectric effect. It is our goal to provide a comprehensive account of the published material so far and to set the stage for a vigorous expansion of the field, with envisioned applications that span from cell biology and signaling to cell and tissue regeneration, antitumoral action, or cell bioengineering to name a fe