26,785 research outputs found
Intersection between class and gender and its effect on the quality of employment in Chile
Indexación: Web of Science; Scopus.En este artículo se analiza el efecto de la intersección entre clase y género sobre la calidad
del empleo en Chile. La medida de posición de clase utilizada está basada en la propuesta de
Erik O. Wright y la calidad del empleo en una medida multidimensional, que incluye un índice
de condiciones objetivas de empleo y dos índices de condiciones subjetivas (motivación en
el trabajo y percepción del control sobre el proceso de trabajo). Los resultados demuestran
que la clase y el género determinan diferencias significativas en la calidad objetiva y subjetiva
del empleo. Sin embargo, los datos también indican que el género (particularmente, el
hecho de ser mujer) no actúa necesariamente como “amplificador” de las desigualdades
de clase observadas en el mercado laboral. A partir de esto, al final del artículo se plantean
algunas reflexiones sobre cómo opera la intersección entre clase y género en el mercado
laboral chileno.This study explores the impact of the intersection between class and gender on the quality
of employment in Chile. The method used to measure social class position is based on the
work of Erik O. Wright, while, for the quality of employment, a multidimensional measurement
was used, including one index for objective working conditions and two indices for subjective
ones (motivation on the job and the perception of control over work processes). The results
demonstrate that class and gender give rise to signifcant differences in objective and
subjective job quality. However, the data also indicate that gender (more specifcally, the fact
of being female) does not necessarily amplify the class-based inequalities observed in the
labour market. Drawing on these fndings, a number of thoughts about how the class/gender
intersection operates in the Chilean labour market are shared in the fnal section of this studyhttp://hdl.handle.net/11362/4079
Riccati nonhermiticity with application to the Morse potential
A supersymmetric one-dimensional matrix procedure similar to relationships of
the same type between Dirac and Schrodinger equations in particle physics is
described at the general level. By this means we are able to introduce a
nonhermitic Hamiltonian having the imaginary part proportional to the solution
of a Riccati equation of the Witten type. The procedure is applied to the
exactly solvable Morse potential introducing in this way the corresponding
nonhermitic Morse problem. A possible application is to molecular diffraction
in evanescent waves over nanostructured surfacesComment: 8 pages, 4 figure
Classical harmonic oscillator with Dirac-like parameters and possible applications
We obtain a class of parametric oscillation modes that we call K-modes with
damping and absorption that are connected to the classical harmonic oscillator
modes through the "supersymmetric" one-dimensional matrix procedure similar to
relationships of the same type between Dirac and Schroedinger equations in
particle physics. When a single coupling parameter, denoted by K, is used, it
characterizes both the damping and the dissipative features of these modes.
Generalizations to several K parameters are also possible and lead to
analytical results. If the problem is passed to the physical optics (and/or
acoustics) context by switching from the oscillator equation to the
corresponding Helmholtz equation, one may hope to detect the K-modes as
waveguide modes of specially designed waveguides and/or cavitiesComment: 14 pages, 9 figures, revised, accepted at J. Phys.
On the Viability of Minimal Neutrinophilic Two-Higgs-Doublet Models
We study the constraints that electroweak precision data can impose, after
the discovery of the Higgs boson by the LHC, on neutrinophilic
two-Higgs-doublet models which comprise one extra doublet
and a new symmetry, namely a spontaneously broken or a softly
broken global . In these models the extra Higgs doublet, via its very
small vacuum expectation value, is the sole responsible for neutrino masses. We
find that the model with a symmetry is basically ruled out by
electroweak precision data, even if the model is slightly extended to include
extra right-handed neutrinos, due to the presence of a very light scalar. While
the other model is still perfectly viable, the parameter space is considerably
constrained by current data, specially by the parameter. In particular, the
new charged and neutral scalars must have very similar masses.Comment: 22 pages, 3 figures, references and comments added, conclusions
unchanged, matches version to appear in JHE
Properties of bright squeezed vacuum at increasing brightness
A bright squeezed vacuum (BSV) is a nonclassical macroscopic state of light, which is generated through high-gain parametric down-conversion or four-wave mixing. Although the BSV is an important tool in quantum optics and has a lot of applications, its theoretical description is still not complete. In particular, the existing description in terms of Schmidt modes with gain-independent shapes fails to explain the spectral broadening observed in the experiment as the mean number of photons increases. Meanwhile, the semiclassical description accounting for the broadening does not allow us to decouple the intermodal photon-number correlations. In this work, we present a new generalized theoretical approach to describe the spatial properties of a multimode BSV. In the multimode case, one has to take into account the complicated interplay between all involved modes: each plane-wave mode interacts with all other modes, which complicates the problem significantly. The developed approach is based on exchanging the (k, t ) and (ω, z) representations and solving a system of integrodifferential equations. Our approach predicts correctly the dynamics of the Schmidt modes and the broadening of the angular distribution with the increase in the BSV mean photon number due to a stronger pumping. Moreover, the model correctly describes various properties of a widely used experimental configuration with two crystals and an air gap between them, namely, an SU(1,1) interferometer. In particular, it predicts the narrowing of the intensity distribution, the reduction and shift of the side lobes, and the decline in the interference visibility as the mean photon number increases due to stronger pumping. The presented experimental results confirm the validity of the new approach. The model can be easily extended to the case of the frequency spectrum, frequency Schmidt modes, and other experimental configurations
Perturbations with angular momentum of Robinson-Trautman spacetimes
We study the possible asymptotically flat perturbations of Robinson-Trautman
spacetimes. We differentiate between algebraically special perturbations and
general perturbations. The equations that determine physically realistic
spacetimes with angular momentum are presented.Comment: 23 pages, no figure
The ELAIS deep X-ray survey - I. Chandra source catalogue and first results
We present an analysis of two deep (75 ks) Chandra observations of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) fields N1 and N2 as the first results from the ELAIS deep X-ray survey. This survey is being conducted in well-studied regions with extensive multiwavelength coverage. Here we present the Chandra source catalogues along with an analysis of source counts, hardness ratios and optical classifications. A total of 233 X-ray point sources are detected in addition to two soft extended sources, which are found to be associated with galaxy clusters. An overdensity of sources is found in N1 with 30 per cent more sources than N2, which we attribute to large-scale structure. A similar variance is seen between other deep Chandra surveys. The source count statistics reveal an increasing fraction of hard sources at fainter fluxes. The number of galaxy-like counterparts also increases dramatically towards fainter fluxes, consistent with the emergence of a large population of obscured sources
The Luminosity Function Evolution of Soft X--ray selected AGN in the RIXOS survey
A sample of 198 soft X--ray selected active galactic nuclei (AGN) from the
ROSAT International X--ray Optical Survey (RIXOS), is used to investigate the
X--ray luminosity function and its evolution. RIXOS, with a flux limit of 3E-14
erg s-1 cm-2 (0.5 to 2.0 keV), samples a broad range in redshift over 20 deg^2
of sky, and is almost completely identified; it is used in combination with the
Einstein Extended Medium Sensitivity Survey (EMSS), to give a total sample of
over 600 AGN. We find the evolution of AGN with redshift to be consistent with
pure luminosity evolution (PLE) models in which the rate of evolution slows
markedly or stops at high redshifts z>1.8. We find that this result is not
affected by the inclusion, or exclusion, of narrow emission line galaxies at
low redshift in the RIXOS and EMSS samples, and is insensitive to uncertainties
in the conversion between flux values measured with ROSAT and Einstein. We
confirm, using a model independent Ve/Va test, that our survey is consistent
with no evolution at high redshifts.Comment: 10 pages, LaTeX file, PS figures and mn.sty. Accepted in MNRA
The Deficit of Distant Galaxy Clusters in the RIXOS X-ray Survey
Clusters of galaxies are the largest gravitationally bound systems and
therefore provide an important way of studying the formation and evolution of
the large scale structure of the Universe. Cluster evolution can be inferred
from observations of the X-ray emission of the gas in distant clusters, but
interpreting these data is not straightforward. In a simplified view, clusters
grow from perturbations in the matter distribution: their intracluster gas is
compressed and shock-heated by the gravitational collapse. The resulting
X-ray emission is determined by the hydrostatic equilibrium of the gas in the
changing gravitational potential. However, if processes such as radiative
cooling or pre-collapse heating of the gas are important, then the X-ray
evolution will be strongly influenced by the thermal history of the gas. Here
we present the first results from a faint flux-limited sample of X-ray selected
clusters compiled as part of the ROSAT International X-ray and Optical Survey
(RIXOS). Very few distant clusters have been identified. Most importantly,
their redshift distribution appears to be inconsistent with simple models based
on the evolution of the gravitational potential. Our results suggest that
radiative cooling or non-gravitational heating of the intracluster gas must
play an important role in the evolution of clusters.Comment: uuencoded compressed postscript. The preprint is also available at
http://www.ast.cam.ac.uk/preprint/PrePrint.htm
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