Interactions and star formation activity in Wolf-Rayet galaxies

We present the main results of the PhD Thesis carried out by L\'opez-S\'anchez (2006), in which a detailed morphological, photometrical and spectroscopical analysis of a sample of 20 Wolf-Rayet (WR) galaxies was realized. The main aims are the study of the star formation and O and WR stellar populations in these galaxies and the role that interactions between low surface companion objects have in the triggering of the bursts. We analyze the morphology, stellar populations, physical conditions, chemical abundances and kinematics of the ionized gas, as well as the star-formation activity of each system.Comment: 16 pages, 15 figure

Influence of coaches training on athletes motivation

El objetivo del estudio era conocer la influencia de las formaciones académica y federativa de los entrenadores sobre los niveles de motivación, diversión, aburrimiento e intención de persistencia en jóvenes deportistas. Para ello, participaron 432 jóvenes con edades entre 10 y 16 años (M = 13,44; DT = 2,92), pertenecientes a disciplinas deportivas individuales (n = 162) y colectivas (n = 270), de género masculino (n = 245) y femenino (n = 187), seleccionados mediante un muestreo por conglomerados. También, participaron 88 entrenadores deportivos, con edades entre los 20 y 56 años (M = 35,79; DT = 9,58). Se llevó a cabo un análisis de diferencias en función de la cualificación académica y federativa de los entrenadores. Los resultados señalaron que los deportistas dirigidos por entrenadores sin formación federativa presentaban mayores niveles de desmotivación. Asimismo, los deportistas entrenados por técnicos sin titulación académica obtuvieron mayores puntuaciones en las regulaciones extrínsecas (identificada y externa). Por tanto, los hallazgos respaldan parcialmente la relevancia de la formación de los entrenadores, obteniéndose diferencias en regulaciones alejadas del máximo nivel de autodeterminación (externa), desmotivación y aburrimientoThe aim of the study was to examine the influence of the coaches´ academic and federative training on motivation, enjoyment, boredom and intention to persist levels in youth athletes. Participants were 432 youth athletes (male = 245, female = 187) ranged from 10 to 16 years old (M = 13.44; SD = 2.92) who participated in individual (n = 163) and collectives sports (n = 270) selected by cluster sampling. Moreover, 88 sport coaches, ranged from 20 to 56 years old (M = 35,79; SD = 9,58), participated in the study. An analysis of differences with regard to academic and federative coaches´ qualification was conducted. Results revealed that athletes trained by coaches without federative training showed greater amotivation levels. Moreover, individuals trained by coaches without academic qualification had higher scores in extrinsic regulation (identified and external). Therefore, findings partially supported the relevance of coaches’ qualification levels, due to the differences found in some extrinsic regulations (external), amotivation and boredo

A guided data projection technique for classi cation of sovereign ratings: the case of European Union 27

Sovereign rating has had an increasing importance since the beginning of the nancial crisis. However, credit rating agencies opacity has been criticised by several authors highlighting the suitability of designing more objective alternative methods. This paper tackles the sovereign credit rating classi cation problem within an ordinal classi cation perspective by employing a pairwise class distances projection to build a classi cation model based on standard regression techniques. In this work the -SVR is selected as the regressor tool. The quality of the projection is validated through the classi cation results obtained for four performance metrics when applied to Standard & Poors, Moody's and Fitch sovereign rating data of U27 countries during the period 2007-2010. This validated projection is later used for ranking visualization which might be suitable to build a decision support syste

Estados desestructurados en situaciones de conflictos armados

Sumario: Introducción. 1. Qué se entiende por Estado desestructurado. 2. Somalia: un caso tipo sobre el que asentar la teoría. 3. Respuestas actuales del Derecho Internacional Humanitario: sus deficiencias y propuestas de lege ferenda

Systematic Study of Electron Localization in an Amorphous Semiconductor

We investigate the electronic structure of gap and band tail states in amorphous silicon. Starting with two 216-atom models of amorphous silicon with defect concentration close to the experiments, we systematically study the dependence of electron localization on basis set, density functional and spin polarization using the first principles density functional code Siesta. We briefly compare three different schemes for characterizing localization: information entropy, inverse participation ratio and spatial variance. Our results show that to accurately describe defect structures within self consistent density functional theory, a rich basis set is necessary. Our study revealed that the localization of the wave function associated with the defect states decreases with larger basis sets and there is some enhancement of localization from GGA relative to LDA. Spin localization results obtained via LSDA calculations, are in reasonable agreement with experiment and with previous LSDA calculations on a-Si:H models.Comment: 16 pages, 11 Postscript figures, To appear in Phys. Rev.

Finite size effects and localization properties of disordered quantum wires with chiral symmetry

Finite size effects in the localization properties of disordered quantum wires are analyzed through conductance calculations. Disorder is induced by introducing vacancies at random positions in the wire and thus preserving the chiral symmetry. For quasi one-dimensional geometries and low concentration of vacancies, an exponential decay of the mean conductance with the wire length is obtained even at the center of the energy band. For wide wires, finite size effects cause the conductance to decay following a non-pure exponential law. We propose an analytical formula for the mean conductance that reproduces accurately the numerical data for both geometries. However, when the concentration of vacancies increases above a critical value, a transition towards the suppression of the conductance occurs. This is a signature of the presence of ultra-localized states trapped in finite regions of the sample.Comment: 5 figures, revtex

The Proteome of Biologically Active Membrane Vesicles from Piscirickettsia salmonis LF-89 Type Strain Identifies Plasmid-Encoded Putative Toxins

Indexación: Scopus.Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs) released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology. Initially, the cytotoxicity of different MV concentration purified from P. salmonis LF-89 was confirmed in an in vivo adult zebrafish infection model. The cumulative mortality of zebrafish injected with MVs showed a dose-dependent pattern. Analyses identified 452 proteins of different subcellular origins; most of them were associated with the cytoplasmic compartment and were mainly related to key functions for pathogen survival. Interestingly, previously unidentified putative virulence-related proteins were identified in P. salmonis MVs, such as outer membrane porin F and hemolysin. Additionally, five amino acid sequences corresponding to the Bordetella pertussis toxin subunit 1 and two amino acid sequences corresponding to the heat-labile enterotoxin alpha chain of Escherichia coli were located in the P. salmonis MV proteome. Curiously, these putative toxins were located in a plasmid region of P. salmonis LF-89. Based on the identified proteins, we propose that the protein composition of P. salmonis LF-89 MVs could reflect total protein characteristics of this P. salmonis type strain. © 2017 Oliver, Hernández, Tandberg, Valenzuela, Lagos, Haro, Sánchez, Ruiz, Sanhueza-Oyarzún, Cortés, Villar, Artigues, Winther-Larsen, Avendaño-Herrera and Yáñez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00420/ful