29,230 research outputs found
Model of the polarized foreground diffuse Galactic emissions from 33 to 353 GHz
We present 3D models of the Galactic magnetic field including regular and
turbulent components, and of the distribution of matter in the Galaxy including
relativistic electrons and dust grains. By integrating along the line of sight,
we construct maps of the polarized Galactic synchrotron and thermal dust
emissions for each of these models. We perform a likelihood analysis to compare
the maps of the Ka, Q, V and W bands of the Wilkinson Microwave Anisotropy
Probe (Wmap) and the 353 GHz Archeops data to the models obtained by varying
the pitch angle of the regular magnetic field, the relative amplitude of the
turbulent magnetic field and the extrapolation spectral indices of the
synchrotron and thermal dust emissions. The best-fit parameters obtained for
the different frequency bands are very similar and globally the data seem to
favor a negligible isotropic turbulent magnetic field component at large
angular scales (an anisotropic line-of-sight ordered component can not be
studied using these data). From this study, we conclude that we are able to
propose a consistent model of the polarized diffuse Galac- tic synchrotron and
thermal dust emissions in the frequency range from 33 to 353 GHz, where most of
the CMB studies are performed and where we expect a mixture of these two main
foreground emissions. This model can be very helpful to estimate the
contamination by foregrounds of the polarized CMB anisotropies, for experiments
like the Planck satellite.Comment: 22 pages, 4 figure
A Relation Between the Kauffman and the HOMFLY Polynomials for Torus Knots
Polynomial invariants corresponding to the fundamental representation of the
gauge group are computed for arbitrary torus knots in the framework of
Chern-Simons gauge theory making use of knot operators. As a result, a formula
which relates the Kauffman and the HOMFLY polynomials for torus knots is
presented.Comment: 47 pages, macropackage phyzzx.tex, minor corrections made, version to
appear in Journal of Mathematical Physic
The use of permanent contracts across Spanish regions: Do regional wage subsidies work?
This article evaluates the effectiveness of regional wage subsidies to foster permanent employment using information gathered from the “Muestra Continua de Vidas Laborales”. This dataset, which is used here for the first time as a source for evaluating Spanish labour market policy, offers a complete employment history for each individual, with no aggregation bias. The policy analyzed consists of a one-time subsidy offered by some Spanish regions for new permanent contracts signed for certain fixed-term employees and unemployed workers. Because our policy variable presents individual, regional and temporal variation, we apply a triple difference estimator to identify the average treatment effect of this policy. We conclude that the outflow into permanent employment of eligible workers improves only minimally under this policy. Nevertheless, the incidence is relatively greater for temporary workers than for unemployed ones and is also larger for younger and middle-aged female workers.Difference-in-difference-in-difference, Causal Evaluation Analysis, Regional Wage Subsidies
Coherent caloritronics in Josephson-based nanocircuits
We describe here the first experimental realization of a heat interferometer,
thermal counterpart of the well-known superconducting quantum interference
device (SQUID). These findings demonstrate, on the first place, the existence
of phase-dependent heat transport in Josephson-based superconducting circuits
and, on the second place, open the way to novel ways of mastering heat at the
nanoscale. Combining the use of external magnetic fields for phase biasing and
different Josephson junction architectures we show here that a number of heat
interference patterns can be obtained. The experimental realization of these
architectures, besides being relevant from a fundamental physics point of view,
might find important technological application as building blocks of
phase-coherent quantum thermal circuits. In particular, the performance of two
different heat rectifying devices is analyzed.Comment: 34 pages, 15 figures, review article for Ultra-low temperatures and
nanophysics ULTN2013. Microkelvin Proceeding
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