SIGAME simulations of the [CII], [OI] and [OIII] line emission from star forming galaxies at z ~ 6

Of the almost 40 star forming galaxies at z>~5 (not counting QSOs) observed in [CII] to date, nearly half are either very faint in [CII], or not detected at all, and fall well below expectations based on locally derived relations between star formation rate (SFR) and [CII] luminosity. Combining cosmological zoom simulations of galaxies with SIGAME (SImulator of GAlaxy Millimeter/submillimeter Emission) we have modeled the multi-phased interstellar medium (ISM) and its emission in [CII], [OI] and [OIII], from 30 main sequence galaxies at z~6 with star formation rates ~3-23Msun/yr, stellar masses ~(0.7-8)x10^9Msun, and metallicities ~(0.1-0.4)xZsun. The simulations are able to reproduce the aforementioned [CII]-faintness at z>5, match two of the three existing z>~5 detections of [OIII], and are furthermore roughly consistent with the [OI] and [OIII] luminosity relations with SFR observed for local starburst galaxies. We find that the [CII] emission is dominated by the diffuse ionized gas phase and molecular clouds, which on average contribute ~66% and ~27%, respectively. The molecular gas, which constitutes only ~10% of the total gas mass is thus a more efficient emitter of [CII] than the ionized gas making up ~85% of the total gas mass. A principal component analysis shows that the [CII] luminosity correlates with the star formation activity as well as average metallicity. The low metallicities of our simulations together with their low molecular gas mass fractions can account for their [CII]-faintness, and we suggest these factors may also be responsible for the [CII]-faint normal galaxies observed at these early epochs.Comment: 24 pages, 14 figures. Accepted for publication in the Astrophysical Journa

Unions, Wage Gaps, and Wage Dispersion: New Evidence from the Americas

Using a common methodology, the effects of unions on wage levels and wage dispersion are estimated for two neighboring countries, Bolivia and Chile, and for the U.S. The analysis shows that unions have broadly similar effects on the wage distribution within these three economies. The findings suggest that the political economy of unions, coupled with market constraints on labor costs, produce commonality in union wage effects that transcend other economic and institutional differences

Machine learning the deuteron

We use machine learning techniques to solve the nuclear two-body bound state problem, the deuteron. We use a minimal one-layer, feed-forward neural network to represent the deuteron S- and D-state wavefunction in momentum space, and solve the problem variationally using ready-made machine learning tools. We benchmark our results with exact diagonalisation solutions. We find that a network with 6 hidden nodes (or 24 parameters) can provide a faithful representation of the ground state wavefunction, with a binding energy that is within 0.1% of exact results. This exploratory proof-of-principle simulation may provide insight for future potential solutions of the nuclear many-body problem using variational artificial neural network techniques.Comment: 8 pages, 7 figures - Final published version including extended analysis and appendice

Universality and Crossover of Directed Polymers and Growing Surfaces

We study KPZ surfaces on Euclidean lattices and directed polymers on hierarchical lattices subject to different distributions of disorder, showing that universality holds, at odds with recent results on Euclidean lattices. Moreover, we find the presence of a slow (power-law) crossover toward the universal values of the exponents and verify that the exponent governing such crossover is universal too. In the limit of a 1+epsilon dimensional system we obtain both numerically and analytically that the crossover exponent is 1/2.Comment: LateX file + 5 .eps figures; to appear on Phys. Rev. Let

Association of fall risk in older adults between gender, fear of falling and autonomy

Aging is a natural process of the individual and is associated with a decline in physical and mental function. Given the high prevalence of older adults worldwide, it becomes ppropriated to identify the consequences of this reduction. The falls appear as a consequence more common in this specific population, which triggers the need to identify the different risk factors, in order to prevent them and create intervention programs in that way.info:eu-repo/semantics/publishedVersio

Levy-Nearest-Neighbors Bak-Sneppen Model

We study a random neighbor version of the Bak-Sneppen model, where "nearest neighbors" are chosen according to a probability distribution decaying as a power-law of the distance from the active site, P(x) \sim |x-x_{ac }|^{-\omega}. All the exponents characterizing the self-organized critical state of this model depend on the exponent \omega. As \omega tends to 1 we recover the usual random nearest neighbor version of the model. The pattern of results obtained for a range of values of \omega is also compatible with the results of simulations of the original BS model in high dimensions. Moreover, our results suggest a critical dimension d_c=6 for the Bak-Sneppen model, in contrast with previous claims.Comment: To appear on Phys. Rev. E, Rapid Communication

Historias de vida e historias lingüísticas : una aproximación a las identidades

Este texto se presentó como comunicación al II Congreso Internacional de Etnografía y Educación: Migraciones y Ciudadanías. Universidad Autónoma de Barcelona, Barcelona, 5-8 Septiembre 2008Desde una perspectiva etnográfica, a través de las historias de vida e historias lingüísticas de niños inmigrados, realizamos una aproximación a sus identidades, como parte constitutiva de la realidad escolar actual. Pretendemos conocer las situaciones de multiculturalidad y plurilingüismo, para formar identidades y contribuir al desarrollo de la convivencia en las escuelas, mediante una metodología interdisciplinar que combina las aportaciones de las Ciencias Sociales, Educativas y Lingüísticas. La aplicación de este estudio es principalmente de tipo educativo, para mejorar la formación inicial de los maestros. Esta comunicación forma parte de una investigación que se realiza en nuestro Departamento en la que, con un enfoque interdisciplinar, participan las áreas de conocimiento de Didáctica y Organización Escolar, Didáctica de la Lengua y Didáctica de las Ciencias Sociales. Adoptamos unas estrategias comunes para construir conocimiento, a fin de integrar las aportaciones procedentes de diversos ámbitos científicos, de manera globalizada y relacional (ALTAVA et al.,1999). Puesto que la realidad es compleja (MORIN, 1994) y que también lo es su conocimiento, asumimos que su aprendizaje requiere la convergencia de distintos clases de saberes procedentes de diferentes ámbitos científicos. En nuestro caso, realizamos aportaciones desde los campos disciplinares de la Lingüística, la Pedagogía y la Didáctica, y desde el conjunto de las Ciencias Sociales (Historia, Antropología, etc.). Nuestro objeto de estudio general es la situación escolar de los niños inmigrantes en la provincia de Castellón, las estrategias didácticas y organizativas que existen en la escuela respecto a la educación intercultural y al multilingüismo.Para lograrlo, en una perspectiva de indagación y acción, dicha investigación pretende dar respuesta a las situaciones de multiculturalidad y plurilingüismo en las escuelas actuales, dentro de la formación (inicial y permanente) de los maestros; todo ello bajo un planteamiento didáctico y académico de una mayor adaptación a la realidad y al proceso de armonización europeas en los programas y metodología docentes