Stellar population gradients in Seyfert 2 galaxies. Northern sample

We use high signal-to-noise ratio long-slit spectra in the 3600-4700A range of the twenty brightest northern Seyfert 2 galaxies to study the variation of the stellar population properties as a function of distance from the nucleus. In order to characterize the stellar population and other continuum sources (e.g. featureless continuum FC) we have measured equivalent widths Ws of six absorption features, four continuum colours and their radial variations, and performed spectral population synthesis as a function of distance from the nucleus. About half the sample has CaIIK and G-band W values smaller at the nucleus than at 1 kpc from it, due to a younger population and/or FC. The stellar population synthesis shows that, while at the nucleus, 75% of the galaxies present contribution > 20% of ages younger or equal than 100Myr and/or of a FC, this proportion decreases to 45% at 3 kpc. In particular, 55% of the galaxies have contribution > 10% of the 3 Myr/FC component (a degenerate component in which one cannot separate what is due to a FC or to a 3 Myr stellar population) at the nucleus, but only 25% of them have this contribution at 3 kpc. As reference, the stellar population of 10 non-Seyfert galaxies, spanning the Hubble types of the Seyfert (from S0 to Sc) was also studied. A comparison between the stellar population of the Seyferts and that of the non-Seyferts shows systematic differences: the contribution of ages younger than 1 Gyr is in most cases larger in the Seyfert galaxies than in non-Seyferts, not only at the nucleus but up to 1 kpc from it.Comment: 23 pages, 18 figures, MNRAS in pres

La autoeficacia y la motivación en el trabajo

Referencia de la publicación original: D. de Quijano, S. & Navarro Cid, J. (2000). La autoeficacia y la motivación en el trabajo. Apuntes de Psicología, 18 (1), 159-177.El presente artículo se centra en el estudio de la autoeficacia como constructo significativo para el análisis y evaluación de la motivación en el trabajo. Sustituye con ventaja el concepto de expectativa de Vroom y ofrece información útil para el diagnóstico y la intervención en la motivación. Basándose en la Escala de autoeficacia general de Jerusalem y Schwarzer y su adaptación española realizada por Baesssler y Schwarzer, los autores de este artículo realizaron una nueva versión de la misma centrada en la autoeficacia general frente al trabajo y la integraron en un instrumento más complejo para el diagnóstico de la motivación. Se ofrecen resultados de la validez y fiabilidad de la escala, así como de su funcionamiento en relación al instrumento más complejo en el que se integra.This paper center in the contributions of self-efficacy to the analysis and evaluation of work motivation. It is argued thet the concept of self-efficacy succesfully replaces Vroom’s concept of expectancy , and offers useful information for diagnose and intervention in motivation. Authors adapt Baessler and Schwarzer’s Spanish adaptation of the Jerusalem and Schwarzer’s Scale of General Self-efficacy, to work situations and integrate it in a broader instrument to motivation diagnose. Validity and rehability data are presented and relations among subscales are considered

Lower and middle Cambrian trilobites of the central Ossa-Morena zone: paleoecological implications

[Resumen] El presente trabajo ofrece datos relacionados con los trilobites y otros invertebrados asociados, que se encuentran en los materiales cámbricos (inferior y medio) en la zona de Ossa-Morena (SO de España), así como las implicaciones paleoecológicas que pueden deducirse de la información que tenemos hasta el momento.[Abstract] In the present paper are given sorne data related to Trilobites and other invenebrate fauna from Lower and Middle Cambrian deposits in Ossa-Morena (SW, Spain) area. Moreover, considerations on paleoecologic implications are deduced from these data

A class of surfaces with planar lines of curvature

En este articulo estudiamos superficies parametrizadas por líneas de curvatura. Obtenemos una caracterización de una clase de superficies con líneas de curvatura planas, esta caracterización depende de ciertas funciones holomorfas. Presentamos una clase de superficies con dos familias de líneas de curvatura planas, esta clase incluye las superficies de Dupin. También damos algunos ejemplos explícitos.In this paper we study surfaces parameterized by lines of curvature. We obtain a characterization of a class of surfaces with planar lines of curvature, this characterization depend on certain holomorphic function. We present a class of surfaces with two family of planar lines of curvature, this class of surfaces includes the Dupin surfaces. Also, we give explicit examples

Obscuring Active Galactic Nuclei with Nuclear Starburst Disks

We assess the potential of nuclear starburst disks to obscure the Seyfert-like AGN that dominate the hard X-ray background at z~1. Over 1200 starburst disk models, based on the theory developed by Thompson et al., are calculated for five input parameters: the black hole mass, the radial size of the starburst disk, the dust-to-gas ratio, the efficiency of angular momentum transport in the disk, and the gas fraction at the outer disk radius. We find that a large dust-to-gas ratio, a relatively small starburst disk, a significant gas mass fraction, and efficient angular momentum transport are all important to produce a starburst disk that can potentially obscure an AGN. The typical maximum star-formation rate in the disks is ~10 solar masses per year. Assuming no mass-loss due to outflows, the starburst disks feed gas onto the black hole at rates sufficient to produce hard X-ray luminosities of 10^{43}-10^{44} erg s^{-1}. The starburst disks themselves should be detectable at mid-infrared and radio wavelengths; at z=0.8, the predicted fluxes are ~1 mJy at 24microns and ~10-30 microJy at 1.4GHz. Thus, we predict a large fraction of radio/X-ray matches in future deep radio surveys. The starburst disks should be easily distinguished from AGN in future 100microns surveys by Herschel with expected fluxes of ~5 mJy. Any AGN-obscuring starbursts will be associated with hot dust, independent of AGN heating, resulting in observable signatures for separating galactic and nuclear star-formation. Finally, because of the competition between gas and star-formation, nuclear starbursts will be associated with lower-luminosity AGN. Thus, this phenomenon is a natural explanation for the observed decrease in the fraction of obscured AGN with luminosity.Comment: 13 pages, 12 figures, 3 in color; accepted by Ap

Understanding motivational climates in physical education classes: How students perceive learning and performance-oriented climates by teachers and peers

This study aimed to translate and validate the Learning and Performance Oriented in Physical Education Climate Questionnaire (LAPOPECQ) in a sample of Portuguese students. Additionally, this study examined if the measurement would be equivalent across samples and gender. For nomological validity, current study examined the relationships of motivational climates oriented by teachers and peers and behavioral regulations in the physical education context. Data from 536 Portuguese students (female = 256) aged 10 and 18 years (M = 13.33; SD = .47) were collected. Participants were involved in regular physical education classes two times per week, according to the Portuguese educational system. The four-correlated factor confirmatory and exploratory model provided acceptable fit to the data. In addition, multigroup analysis showed invariance among groups, namely between calibration and validation samples, and female and male students. Last, significant correlations were found between motivational climates and behavioral regulations as theoretically proposed, confirming nomological validity. The translated LAPOPECQ into Portuguese is a valid instrument assessing students’ perception of motivational climates oriented by teachers and peers.info:eu-repo/semantics/publishedVersio

The ionization mechanism of NGC 185: how to fake a Seyfert galaxy?

NGC 185 is a dwarf spheroidal satellite of the Andromeda galaxy. From mid-1990s onwards it was revealed that dwarf spheroidals often display a varied and in some cases complex star formation history. In an optical survey of bright nearby galaxies, NGC 185 was classified as a Seyfert galaxy based on its emission line ratios. However, although the emission lines in this object formally place it in the category of Seyferts, it is probable that this galaxy does not contain a genuine active nucleus. NGC 185 was not detected in radio surveys either in 6 or 20 cm, or X-ray observations, which means that the Seyfert-like line ratios may be produced by stellar processes. In this work, we try to identify the possible ionization mechanisms for this galaxy. We discussed the possibility of the line emissions being produced by planetary nebulae (PNe), using deep spectroscopy observations obtained with GMOS-N, at Gemini. Although the fluxes of the PNe are high enough to explain the integrated spectrum, the line ratios are very far from the values for the Seyfert classification. We then proposed that a mixture of supernova remnants and PNe could be the source of the ionization, and we show that a composition of these two objects do mimic Seyfert-like line ratios. We used chemical evolution models to predict the supernova rates and to support the idea that these supernova remnants should be present in the galaxy.Comment: 9 pages, 7 figures, accepted for publication in MNRA

Optical coherence tomography- a non-invasive technique applied to conservation of paintings

It is current practice to take tiny samples from a painting to mount and examine in cross-section under a microscope. However, since conservation practice and ethics limit sampling to a minimum and to areas along cracks and edges of paintings, which are often unrepresentative of the whole painting, results from such analyses cannot be taken as representative of a painting as a whole. Recently in a preliminary study, we have demonstrated that near-infrared Optical Coherence Tomography (OCT) can be used directly on paintings to examine the cross-section of paint and varnish layers without contact and the need to take samples. OCT is an optical interferometric technique developed for in vivo imaging of the eye and biological tissues; it is essentially a scanning Michelson’s interferometer with a ‘broadband’ source that has the spatial coherence of a laser. The low temporal coherence and high spatial concentration of the source are the keys to high depth resolution and high sensitivity 3D imaging. The technique is non-invasive and noncontact with a typical working distance of 2 cm. This non-invasive technique enables cross-sections to be examined anywhere on a painting. In this paper, we will report new results on applying near-infrared en-face OCT to paintings conservation and extend the application to the examination of underdrawings, drying processes, and quantitative measurements of optical properties of paint and varnish layers