Internal Kinematics of Luminous Compact Blue Galaxies

We describe the dynamical properties which may be inferred from HST/STIS spectroscopic observations of luminous compact blue galaxies (LCBGs) between 0.1<z<0.7. While the sample is homogeneous in blue rest-frame color, small size and line-width, and high surface-brightness, their detailed morphology is eclectic. Here we determine the amplitude of rotation versus random, or disturbed motions of the ionized gas. This information affirms the accuracy of dynamical mass and M/L estimates from Keck integrated line-widths, and hence also the predictions of the photometric fading of these unusual galaxies. The resolved kinematics indicates this small subset of LCBGs are dynamically hot, and unlikely to be embedded in disk systems.Comment: To appear in "Starbursts: from 30 Doradus to Lyman Break Galaxies" 2005, eds. R. de Grijs and R. M. Gonzalez Delgado (Kluwer

Spherical Scalar Field Halo in Galaxies

We study a spherically symmetric fluctuation of scalar dark matter in the cosmos and show that it could be the dark matter in galaxies, provided that the scalar field has an exponential potential whose overall sign is negative and whose exponent is constrained observationally by the rotation velocities of galaxies. The local space-time of the fluctuation contains a three dimensional space-like hypersurface with surplus of angle.Comment: 5 REVTeX pages, no figures. Contains important suggestions provided by the referee. Final version, to appear in Phys. Rev.

Casimir torque

We develop a formalism for the calculation of the flow of angular momentum carried by the fluctuating electromagnetic field within a cavity bounded by two flat anisotropic materials. By generalizing a procedure employed recently for the calculation of the Casimir force between arbitrary materials, we obtain an expression for the torque between anisotropic plates in terms of their reflection amplitude matrices. We evaluate the torque in 1D for ideal and realistic model materials.Comment: 8 pages, 4 figs, Submitted to Proc. of QFEXT'05, to appear in J. Phys.

On the Space Time of a Galaxy

We present an exact solution of the averaged Einstein's field equations in the presence of two real scalar fields and a component of dust with spherical symmetry. We suggest that the space-time found provides the characteristics required by a galactic model that could explain the supermassive central object and the dark matter halo at once, since one of the fields constitutes a central oscillaton surrounded by the dust and the other scalar field distributes far from the coordinate center and can be interpreted as a halo. We show the behavior of the rotation curves all along the background. Thus, the solution could be a first approximation of a ``long exposition photograph'' of a galaxy.Comment: 8 pages REVTeX, 11 eps figure

Impacto de la convivencia escolar sobre el rendimiento académico, desde la percepción de estudiantes con desarrollo típico y necesidades educativas especiales

This descriptive correlational study aims to compare the perception about eight dimensions of school coexistence of typically developing high school students (n = 545) and students with special educational needs (n = 75) from Chile and their relationship with the general academic performance.  Based on the analysis of hierarchical and non-hierarchical clusters, multiple regression and logistic regression, it was found that students with special educational needs have a less favorable perception in almost every dimension analyzed; especially, in those aspects related to school victimization, aggression, and indiscipline. Likewise, they perceive that they have a limited peer social network, as well as limited normative adjustment and a lower perception about their own positive interpersonal skills. The multiple regression and logistic regression models allow confirming that the dimensions of school coexistence account for between 20% and 27% of the academic performance variability. The aforementioned models highlight the role and negative effect of the level of victimization perceived by students, as well as the perception about the occurrence of indiscipline situations in the classroom, and the fact of belonging to the group of students with special educational needs, and to the group of male students. The findings are analyzed and discussed in light of the implications for high social vulnerability educational contexts.This descriptive correlational study aims to compare the perception about eight dimensions of school coexistence of typically developing high school students (n = 545) and students with special educational needs (n = 75) from Chile and their relationship with the general academic performance.  Based on the analysis of hierarchical and non-hierarchical clusters, multiple regression and logistic regression, it was found that students with special educational needs have a less favorable perception in almost every dimension analyzed; especially, in those aspects related to school victimization, aggression, and indiscipline. Likewise, they perceive that they have a limited peer social network, as well as limited normative adjustment and a lower perception about their own positive interpersonal skills. The multiple regression and logistic regression models allow confirming that the dimensions of school coexistence account for between 20% and 27% of the academic performance variability. The aforementioned models highlight the role and negative effect of the level of victimization perceived by students, as well as the perception about the occurrence of indiscipline situations in the classroom, and the fact of belonging to the group of students with special educational needs, and to the group of male students. The findings are analyzed and discussed in light of the implications for high social vulnerability educational contexts.Estudio descriptivo-correlacional que busca comparar la percepción acerca de ocho dimensiones de la convivencia escolar de estudiantes chilenos de educación media con desarrollo típico (n=545) y con necesidades educativas especiales (n=75), y su relación con el rendimiento académico general. A partir de los análisis de conglomerados jerárquico y no jerárquico, regresión múltiple y regresión logística, se constata que los estudiantes con necesidades educativas especiales tienen una percepción más desfavorable en casi todas las dimensiones analizadas, especialmente en aquellos aspectos asociados a la victimización escolar y agresión e indisciplina, de igual forma, perciben tener una menor red social de iguales, menor ajuste normativo y una más baja percepción respecto de la gestión interpersonal positiva. Los modelos de regresión múltiple y regresión logística, permiten constatar que las dimensiones de la convivencia escolar explican entre el 20% y el 27% de la variabilidad del rendimiento académico. En dichos modelos destaca el papel y efecto negativo que tiene la el grado de victimización que perciben los estudiantes, como también la percepción respecto de la ocurrencia o presencia de situaciones de indisciplina al interior del aula, como también el hecho de pertenecer al grupo de estudiantes con necesidades educativas especiales, y el pertenecer al grupo de estudiantes hombres. Se analizan y discuten los hallazgos a la luz de las implicaciones para contextos educativos de alta vulnerabilidad social

Subtraction of test mass angular noise in the LISA Technology Package interferometer

We present recent sensitivity measurements of the LISA Technology Package interferometer with articulated mirrors as test masses, actuated by piezo-electric transducers. The required longitudinal displacement resolution of 9 pm/sqrt[Hz] above 3 mHz has been demonstrated with an angular noise that corresponds to the expected in on-orbit operation. The excess noise contribution of this test mass jitter onto the sensitive displacement readout was completely subtracted by fitting the angular interferometric data streams to the longitudinal displacement measurement. Thus, this cross-coupling constitutes no limitation to the required performance of the LISA Technology Package interferometry.Comment: Applied Physics B - Lasers and Optics (2008