1,112 research outputs found
The wage gap between immigrant and native workers in Spain: an analysis using matched employer-employee data
The fact that Spain has witnessed a sharp increase in the number of immigrants over the past decade has generated considerable interest, particularly as regards wages earned by immigrants in host industries. We analyze whether controlling for both observable and unobservable characteristics of employers —in addition to individual variables and the economic context— makes any difference as regards the debate regarding the existence of wage differences between immigrant and native workers in Spain. As we show, doing this considerably reduces (or even eliminates) the inequalities found in previous research, thereby questioning the results attained by previous studies on this issue.Immigration, salaries, assimilation.
On the relation between the IR continuum and the active galactic nucleus in Seyfert galaxies
A sample of the brightest known Seyfert galaxies from the CfA sample is
analyzed on the basis of ISO photometric and spectroscopic data.
Regardless of the Seyfert type, the mid-IR continuum emission from these
galaxies is found to be correlated with the coronal line emission arising in
the nuclear active region. Conversely, the correlation degrades progressively
when moving from the mid- to the far-IR emission, where it ends to vanish. It
is concluded that the mid-IR emission is largely dominated by dust heated by
processes associated with the active nucleus whereas the far-IR is a different
component most probably unrelated with the active region. We suggest that the
far-IR component is due to dust heated by the stellar population in the disks
of these galaxies.Comment: 6 pages, 3 figures To be published in Astronomy and Astrophysic
Interaction between a laser beam and semiconductor nanowires: application to the raman spectrum of Si nanowires
One presents in this work the study of the interaction between a focused laser beam and Si nanowires (NWs). The NWs heating induced by the laser beam is studied by solving the heat transfer equation by finite element methods (fem). This analysis permits to establish the temperature distribution inside the NW when it is excited by the laser beam. The overheating is dependent on the dimensions of the NW, both the diameter and the length. When performing optical characterization of the NWs using focused laser beams, one has to consider the temperature increase introduced by the laser beam. An important issue concerns the fact that the NWs diameter has subwavelength dimensions, and is also smaller than the focused laser beam. The analysis of the thermal behaviour of the NWs under the excitation with the laser beam permits the interpretation of the Raman spectra of Si NWs, where it is demonstrated that temperature induced by the laser beam play a major role in shaping the Raman spectrum of Si NW
Participación vegetal en la construcción de los sistemas dunares litorales de Mallorca
[Resumen] Se establecen las relaciones entre la zonación vegetal y las áreas geomorfológicas de los sistemas dunares litorales de la isla de Mallorca. Para ello, se clasifican dichos sistemas en cuatro categorías en base a criterios morfológicos y de vegetación y se analiza la situación actual en cada uno de ellos, definiendose el papel que juega la vegetación en su arquitectura..[Abstract] The relationship between plant zonation and geomorphological areas have been studied in the coastal dunar systems of the island of Mallorca. Trough a four type classification based in vegetation and morphological criteria we point out their state of conservation and the role of the vegetation in their build-up
Interaction between a laser beam and semiconductor nanowires: application to the raman spectrum of Si nanowires
One presents in this work the study of the interaction between a focused laser beam and Si nanowires (NWs). The NWs heating induced by the laser beam is studied by solving the heat transfer equation by finite element methods (FEM). This analysis permits to establish the temperature distribution inside the NW when it is excited by the laser beam. The overheating is dependent on the dimensions of the NW, both the diameter and the length. When performing optical characterisation of NWs using focused laser beams, one has to consider the temperature increase introduced by the laser beam. An important issue concerns the fact that the NW's diameter has subwavelength dimensions, and is also smaller than the focused laser beam. The analysis of the thermal behaviour of the NWs under the excitation with the laser beam permits the interpretation of the Raman spectrum of Si NWs. It is demonstrated that the temperature increase induced by the laser beam plays a major role in shaping the Raman spectrum of Si NWs
Raman spectrum of group IV nanowires: influence of temperature
Group IV semiconductor nanowires are characterized by Raman spectroscopy. The results are analyzed in terms of the heating induced by the laser beam on the nanowires. By solving the heat transport equation one can simulate the temperature reached by the NWs under the exposure to a laser beam. The results are illustrated with Si and Si1-xGex nanowires. Both bundles of nanowires and individual nanowires are studied. The main experimental conditions contributing to the nanowire heating are discusse
VLT diffraction-limited imaging at 11 and 18 micron of the nearest active galactic nuclei
Mid-infrared imaging at resolutions of 300 mas of the central kpc region of
13 nearby, well-known active galaxies is presented. The bulk of the mid-IR
emission is concentrated on an unresolved central source within a size of less
than 5 to 130 pc, depending on the object distance. Further resolved emission
is detected in 70% of the sample in the form of circumnuclear star-forming
rings or diffuse nuclear extended emission. In the three cases with
circumnuclear star formation, the stellar contribution is at least as important
as that of the AGN. In those with extended nuclear emission -- a third of the
sample -- this emission represents a few per cent of the total measured;
however, this contribution may be underestimated because of the chopped nature
of these observations. This extended emission is generally collimated in a
preferential direction often coinciding with that of the extended ionized gas
or the jet.
In all cases, the nuclear fluxes measured at 11.8 and 18.7 micron represent a
minor contribution of the flux levels measured by large aperture IRAS data at
the nearest energy bands of 12 and 25 micron. This contribution ranges from 30%
to less than 10%. In only three cases do the AGN fluxes agree with IRAS to
within a factor of 2. In the AGNs with strong circumnuclear star formation,
this component can well account for most of the IRAS flux measured in these
objects. But in all other cases, either a low surface brightness component
extending over galactic scales or strong extra-nuclear IR sources -- e.g. HII
regions in spiral arms -- have to be the main source of the IRAS emission. In
either case, the contribution of these components dwarfs that of the AGN at
mid-IR wavelengths.Comment: 17 pages, 10 figures. Accepted for publication in MNRA
Differences of the game between the football Spanish team and its rivals.
El objeto de este estudio, analizando la acción de juego en fútbol, describe el uso de los contextos de interacción que la selección española de fútbol y sus rivales hicieron en los campeonatos internacionales. Para ello, 13 partidos fueron observados y codificados (seis de la Eurocopa 2008 y siete del Mundial 2010) gracias a un sistema taxonómico ad hoc previamente definido. Los datos fueron registrados usando un software específico. Después, coordenadas polares fueron desarrolladas usando sólo como conductas criterio los contextos de interacción. Los resultados obtenidos describen que España y sus oponentes no hicieron el mismo uso del espacio de juego en sus partidos (más ofensivo para los primeros), mostrando la dimensión diacrónica de los eventos y combinando las perspectivas prospectiva y retrospectiva. Esto nos permite saber el componente estratégico del uso de los contextos de interacción hechos por los equipos en la competición y optimizar programas de entrenamiento específicos.Este estudio es parte del proyecto titulado Avances Tecnológicos y Metodológicos en la Automatización de Estudios observacionales en deporte, financiado por Dirección General de Investigación de España, Ministerio de Ciencia e Innovación (PSI2008-01179) en el período 2008-2011. No existen conflictos de intereses para esta investigación
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