77,377 research outputs found
Environmental problems and opportunities of the peri-urban interface and their impact upon the poor
The objective of this document is to provide an overview of the problems and opportunities of the peri-urban interface (PUI) with regard to the broad concerns of environmentalsustainability and poverty
Effect of nanosize BaZrO3 inclusions on vortex parameters in YBaCuO
We report on the field dependence of the microwave complex resistivity data
in YBaCuO/BaZrO films grown by PLD at various BaZrO
content. The data, analyzed within a recently developed general framework for
the mixed-state microwave response of superconductors, yield the field
dependence of the fluxon parameters such as the vortex viscosity and the
pinning constant. We find that pinning undergoes a change of regime when the
BaZrO content in the target increases from 2.5 mol.% to 5 mol.%.
Simultaneously, the vortex viscosity becomes an increasing function of the
applied magnetic field. We propose a scenario in which flux lines are pinned as
bundles, and a crossover from dilute point pins to dense c-axis correlated
defects takes place between 2.5 and 5 mol.% in the BZO concentration. Our data
are inconsistent with vortices occupying mainly the BaZrO sites at low
fields, and suggest instead that vortices occupy both BaZrO sites and
interstitials in the YBaCuO matrix, even at low fields.Comment: Presented at EUCAS 2009, to be published in J. Phys.:Conf. Serie
Combining Physical galaxy models with radio observations to constrain the SFRs of high-z dusty star forming galaxies
We complement our previous analysis of a sample of z~1-2 luminous and
ultra-luminous infrared galaxies ((U)LIRGs), by adding deep VLA radio
observations at 1.4 GHz to a large data-set from the far-UV to the sub-mm,
including Spitzer and Herschel data. Given the relatively small number of
(U)LIRGs in our sample with high S/N radio data, and to extend our study to a
different family of galaxies, we also include 6 well sampled near IR-selected
BzK galaxies at z~1.5. From our analysis based on the radiative transfer
spectral synthesis code GRASIL, we find that, while the IR luminosity may be a
biased tracer of the star formation rate (SFR) depending on the age of stars
dominating the dust heating, the inclusion of the radio flux offers
significantly tighter constraints on SFR. Our predicted SFRs are in good
agreement with the estimates based on rest-frame radio luminosity and the Bell
(2003) calibration. The extensive spectro-photometric coverage of our sample
allows us to set important constraints on the SF history of individual objects.
For essentially all galaxies we find evidence for a rather continuous SFR and a
peak epoch of SF preceding that of the observation by a few Gyrs. This seems to
correspond to a formation redshift of z~5-6. We finally show that our physical
analysis may affect the interpretation of the SFR-M* diagram, by possibly
shifting, with respect to previous works, the position of the most dust
obscured objects to higher M* and lower SFRs.Comment: 26 pages, 15 figures, 3 tables, accepted for publication in MNRAS on
Dec. 4th, 201
Surface Tension in Unitary Fermi Gases with Population Imbalance
We study the effects of surface tension between normal and superfluid regions
of a trapped Fermi gas at unitarity. We find that surface tension causes
notable distortions in the shape of large aspect ratio clouds. Including these
distortions in our theories resolves many of the apparent discrepancies among
different experiments and between theory and experiments.Comment: 4 pages, 4 figures, Published versio
Vortex solutions of the Lifshitz-Chern-Simons theory
We study vortex-like solutions to the Lifshitz-Chern-Simons theory. We find
that such solutions exists and have a logarithmically divergent energy, which
suggests that a Kostelitz-Thouless transition may occur, in which
voxtex-antivortex pairs are created above a critical temperature. Following a
suggestion made by Callan and Wilzcek for the global U(1) scalar field model,
we study vortex solutions of the Lifshitz-Chern-Simons model formulated on the
hyperbolic plane, finding that, as expected, the resulting configurations have
finite energy. For completeness, we also explore Lifshitz-Chern-Simons vortex
solutions on the sphere.Comment: Published version, added appendix on electromagnetic duality in
Lifshitz system
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