Electron and Phonon Temperature Relaxation in Semiconductors Excited by Thermal Pulse

Electron and phonon transient temperatures are analyzed in the case of nondegenerate semiconductors. An analytical solution is obtained for rectangular laser pulse absorption. It is shown that thermal diffusion is the main energy relaxation mechanism in the phonon subsystem. The mechanism depends on the correlation between the sample length and the electron cooling length in an electron subsystem. Energy relaxation occurs by means of the electron thermal diffusion in thin samples (), and by means of the electron-phonon energy interaction in thick samples (). Characteristic relaxation times are obtained for all the cases, and analysis of these times is made. Electron and phonon temperature distributions in short and long samples are qualitatively and quantitatively analyzed for different correlations between the laser pulse duration and characteristic times.Comment: 33 pages, 16 figure

870 micron continuum observations of the bubble-shaped nebula Gum 31

We are presenting here a study of the cold dust in the infrared ring nebula Gum 31. We aim at deriving the physical properties of the molecular gas and dust associated with the nebula, and investigating its correlation with the star formation in the region, that was probably triggered by the expansion of the ionization front. We use 870 micron data obtained with LABOCA to map the dust emission. The obtained LABOCA image was compared to archival IR,radio continuum, and optical images. The 870 micron emission follows the 8 micron (Spitzer), 250 micron, and 500 micron (Herschel) emission distributions showing the classical morphology of a spherical shell. We use the 870 micron and 250 micron images to identify 60 dust clumps in the collected layers of molecular gas using the Gaussclumps algorithm. The clumps have effective deconvolved radii between 0.16 pc and 1.35 pc, masses between 70 Mo and 2800 Mo, and volume densities between 1.1x10^3 cm^-3 and 2.04x10^5 cm^-3. The total mass of the clumps is 37600 Mo. The dust temperature of the clumps is in the range from 21 K to 32 K, while inside the HII region reaches ~ 40 K. The clump mass distribution is well-fitted by a power law dN/dlog(M/Mo) proportional to M^(-alpha), with alpha=0.93+/-0.28. The slope differs from those obtained for the stellar IMF in the solar neighborhood, suggesting that the clumps are not direct progenitors of single stars/protostars. The mass-radius relationship for the 41 clumps detected in the 870 microns emission shows that only 37% of them lie in or above the high-mass star formation threshold, most of them having candidate YSOs projected inside. A comparison of the dynamical age of the HII region with the fragmentation time, allowed us to conclude that the collect and collapse mechanism may be important for the star formation at the edge of Gum 31, although other processes may also be acting.Comment: 15 pages, 10 figures. Accepted for publication in A&

Parental education styles as a predictor of sport success and competition level

Los objetivos de este trabajo fueron comprobar cuáles son las diferencias en el nivel de competición deportivo en función de los estilos educativos de los padres, y conocer cuáles son las diferencias en los éxitos deportivos en función de los estilos educativos de los padres. Se administró un Cuestionario Sociodemográfico ad hoc, el Test Autoevaluativo Multifactorial de Adaptación Infantil (TAMAI) y la Escala de Oviedo de Infrecuencia de Respuesta (INF-OV). La muestra se compuso de 502 deportistas españoles. Los resultados mostraron que los deportistas sin éxitos internacionales obtuvieron diferencias significativas y mayores puntuaciones de restricción de la madre. Por otro lado, la educación asistencial próxima al proteccionismo de la madre obtuvo diferencias significativas y mayores puntuaciones en los deportistas que no compiten a nivel internacional. Se concluyó que las madres protectoras no se relacionan con tener hijos que compiten a nivel internacional y las madres restrictivas no se relacionan con tener hijos con éxitos a nivel internacionalThe objectives of this research were to check the differences in the level of sport competition depending on parental education styles, and to know what the differences are in parental education styles in terms of sport success. In order to measure the different variables an ad hoc sociodemographic questionnaire, the Multifactor Self-Assessment Test of Child Adjustment (TAMAI) and the Oviedo Scale of Infrequency of Response (INF-OV) were carried out. The sample consisted of 502 Spanish athletes. The results showed that athletes without international success obtained higher scores and significant differences in mother´s restriction. Moreover, the mother’s care education close to protectionism showed significant differences in benefit of athletes who do not compete internationally. It was concluded that protective mothers are not related to having children who compete internationally and restrictive mothers are not related to having children who achieve international succes

The Impact of the Economic Downturn in the Spanish Civil Justice System

The Spanish justice system has been shaken by the econom- ic downturn as many other institutions have. This article addresses in the first place some statistical data that shed light as regards to the number of judges and the costs and length of the procedure in Spain. These figures help to understand, in the second place, the impact of austerity measures on the judiciary, namely, the freeze on the hiring of judges and the establishing of high court fees. While they mainly concern the supply side of justice services, others such cost reductions in legal aid have had, in the third place, an impact on the demand side, driving many citizens to social exclusion and to resorting to self-defence mecha-nisms. The final part of this article addresses some remedies that may alleviate judiciary’s workload, but that fall short of doing it. All in all, the Spanish justice system seems to require a holistic approach to patch up edges, but one in which the role of judge-made justice in a democratic society has to be central again

A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2

The origin of the Galactic halo stellar structure known as the Monoceros ring is still under debate. In this work, we study that halo substructure using deep CFHT wide-field photometry obtained for the globular clusters NGC2419 and Koposov2, where the presence of Monoceros becomes significant because of their coincident projected position. Using Sloan Digital Sky Survey photometry and spectroscopy in the area surrounding these globulars and beyond, where the same Monoceros population is detected, we conclude that a second feature, not likely to be associated with Milky Way disk stars along the line-of-sight, is present as foreground population. Our analysis suggests that the Monoceros ring might be composed of an old stellar population of age t ~ 9Gyr and a new component ~ 4Gyr younger at the same heliocentric distance. Alternatively, this detection might be associated with a second wrap of Monoceros in that direction of the sky and also indicate a metallicity spread in the ring. The detection of such a low-density feature in other sections of this halo substructure will shed light on its nature.Comment: 10 pages, 10 figures, accepted for publication in Ap

Three dimensional finite element model of a non-crimp fabric laminated using geometrically straight tows with crimped material properties

COMATCOMP 09 : Donostia - San Sebastian, 7, 8 y 9 de octubre de 2009The compressive failure of a [0,90]n non-crimp fabric laminate is studied using a 3D finite element model of the representative unit cell at mesoscopic scale. In previous analyses, tow elements coordinate systems were oriented in the actual direction of the fibres. Therefore, the same transversely isotropic mechanical behaviour was employed for every tow element (defined in the element coordinate system). A new approach is presented in this work, in which the geometrical crimp of the tows is neglected and straight tows are created. The actual crimp of the fibres is considered by introducing suitable anisotropic material properties in each zone of the tow. Anisotropic properties have been obtained by a rotation of the actual transversely isotropic mechanical behaviour, taking into account the actual orientation of the crimped fibres. This approach requires a larger amount of work to define the material properties but, on the contrary, the mesh can be easily created for any configuration. Results obtained with the new approach (i.e., the ‘straight tows’ model) have been successfully compared with those of the previous analyses (i.e., the ‘crimped tows’ model)

Caracterización de grietas de delaminación en laminados 0/90 simétricos

IV CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Gijón, los días 21,22 y 23 de Noviembre de 2001La presencia en un laminado de láminas a 90° con respecto a la dirección preferente de la carga origina la aparición casi inmediata de grietas transversales (paralelas a las fibras) en la lámina a 90º,que alcanzan la interfase con la lámina vecina, presumiblemente a 0º. Esto puede originar la bifurcación de la grieta, que se propaga ahora en forma de delaminación entre las dos láminas. El objetivo de este estudio es el caracterizar el estado tensional en el fondo de la grieta de delaminación para diferentes longitudes de la misma. Ello es el primer paso para establecer los criterios de Mecánica de la Fractura que deben ser aplicados en la predicción de la aparición y propagación de este tipo de daño.The presence in a laminate of laminas oriented 90 degrees with respect to the preferent direction of load generates almost immediately the appearance in these laminas of cracks transversal to the load (parallel to the fibres in the lamina). These cracks reach the interface with the neighbour lamina, which is usually oriented 0 degrees. This can originate the bifurcation of the crack, which appears now propagating as a delamination crack between the two laminas. The objective of this study is to characterize the stress state at the tip crack of the delamination crack for different lengths of the crack. This is the first step to establish appropriate criteria based on Fracture Mechanics to predict the appearance and growth of this type of damage

Essential and checkpoint functions of budding yeast ATM and ATR during meiotic prophase are facilitated by differential phosphorylation of a meiotic adaptor protein, Hop1

A hallmark of the conserved ATM/ATR signalling is its ability to mediate a wide range of functions utilizing only a limited number of adaptors and effector kinases. During meiosis, Tel1 and Mec1, the budding yeast ATM and ATR, respectively, rely on a meiotic adaptor protein Hop1, a 53BP1/Rad9 functional analog, and its associated kinase Mek1, a CHK2/Rad53-paralog, to mediate multiple functions: control of the formation and repair of programmed meiotic DNA double strand breaks, enforcement of inter-homolog bias, regulation of meiotic progression, and implementation of checkpoint responses. Here, we present evidence that the multi-functionality of the Tel1/Mec1-to-Hop1/Mek1 signalling depends on stepwise activation of Mek1 that is mediated by Tel1/Mec1 phosphorylation of two specific residues within Hop1: phosphorylation at the threonine 318 (T318) ensures the transient basal level Mek1 activation required for viable spore formation during unperturbed meiosis. Phosphorylation at the serine 298 (S298) promotes stable Hop1-Mek1 interaction on chromosomes following the initial phospho-T318 mediated Mek1 recruitment. In the absence of Dmc1, the phospho-S298 also promotes Mek1 hyper-activation necessary for implementing meiotic checkpoint arrest. Taking these observations together, we propose that the Hop1 phospho-T318 and phospho-S298 constitute key components of the Tel1/Mec1- based meiotic recombination surveillance (MRS) network and facilitate effective coupling of meiotic recombination and progression during both unperturbed and challenged meiosis

Black hole mass estimates in quasars - A comparative analysis of high- and low-ionization lines

The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the quasar broad line region (BLR) structure and dynamics, including perhaps the earliest unambiguous evidence in favor of a disk + wind structure in radio-quiet quasars. We carried out an analysis of the CIV 1549 and Hbeta line profiles of 28 Hamburg-ESO high luminosity quasars and of 48 low-z, low luminosity sources in order to test whether the high-ionization line CIV 1549 width could be correlated with Hbeta and be used as a virial broadening estimator. We analyze intermediate- to high-S/N, moderate resolution optical and NIR spectra covering the redshifted CIV and H$\beta$ over a broad range of luminosity log L ~ 44 - 48.5 [erg/s] and redshift (0 - 3), following an approach based on the quasar main sequence. The present analysis indicates that the line width of CIV 1549 is not immediately offering a virial broadening estimator equivalent to H$\beta$. At the same time a virialized part of the BLR appears to be preserved even at the highest luminosities. We suggest a correction to FWHM(CIV) for Eddington ratio (using the CIV blueshift as a proxy) and luminosity effects that can be applied over more than four dex in luminosity. Great care should be used in estimating high-L black hole masses from CIV 1549 line width. However, once corrected FWHM(CIV) values are used, a CIV-based scaling law can yield unbiased MBH values with respect to the ones based on H$\beta$ with sample standard deviation ~ 0.3 dex.Comment: 43 pages, 15 Figures, submitted to A&

Boundary Element Analysis of Three-Dimensional Exponentially Graded Isotropic Elastic Solids

A numerical implementation of the Somigliana identity in displacements for the solution of 3D elastic problems in exponentially graded isotropic solids is presented. An expression for the fundamental solution in displacements, Uj , was deduced by Martin et al. (Proc. R. Soc. Lond. A, 458, pp. 1931–1947, 2002). This expression was recently corrected and implemented in a Galerkin indirect 3D BEM code by Criado et al. (Int. J. Numer. Meth. Engng., 2008). Starting from this expression of Uj , a new expression for the fundamental solution in tractions Tj has been deduced in the present work. These quite complex expressions of the integral kernels Uj and Tj have been implemented in a collocational direct 3D BEM code. The numerical results obtained for 3D problems with known analytic solutions verify that the new expression for Tj is correct. Excellent accuracy is obtained with very coarse boundary element meshes, even for a relativelyMinisterio de Educación Cultura y Deporte SAB2003-0088Ministerio de Ciencia y Tecnología MAT2003-0331