8,647 research outputs found
The Spanish 1898 disaster: the drift towards national-protectionism
An econometric analysis of Spanish aggregate and sectoral data reveals that the loss of the last colonial possessions in 1898 was not, in fact an economic disaster of the catastrophic proportions sorne traditional historians had held. Both at the aggregate level and in the sectors most directly involved in the colonial trade, the events of 1898 were not a specially relevant watershed. However, the nationalistic sentiment, and the climate of public opinion created by the defeat in the 1898 Spanish-American War induced a favorable institutional framework for the adoption of autarkic measures, especially high tariffs. This produced in subsequent years a progressive separation of the Spanish economy from international markets. This indirect and institutional effect, rather than the direct loss from the war itself, was the real economic disaster of 1898
Electromagnetic fields and transport coefficients in a hot pion gas
We present recent results on finite temperature electromagnetic form factors
and the electrical conductivity in a pion gas. The standard Chiral Perturbation
Theory power counting needs to be modified for transport coefficients. We pay
special attention to unitarity and to possible applications for dilepton and
photon production.Comment: 4pp, 2 figures, talk given at "Strong and Electroweak Matter 2006",
BNL, May 200
Motion segmentation by consensus
We present a method for merging multiple partitions into a single partition, by minimising the ratio of pairwise agreements and contradictions between the equivalence relations corresponding to the partitions. The number of equivalence classes is determined automatically. This method is advantageous when merging segmentations obtained independently. We propose using this consensus approach to merge segmentations of features tracked on video. Each segmentation is obtained by clustering on the basis of mean velocity during a particular time interva
Transport coefficients of a massive pion gas
We review or main results concerning the transport coefficients of a light
meson gas, in particular we focus on the case of a massive pion gas. Leading
order results according to the chiral power-counting are presented for the DC
electrical conductivity, thermal conductivity, shear viscosity, and bulk
viscosity. We also comment on the possible correlation between the bulk
viscosity and the trace anomaly in QCD, as well as the relation between
unitarity and a minimum of the quotient near the phase transition.Comment: Talk given at the 5th International Conference on Quarks and Nuclear
Physics (QNP09), Beijing, September 21-26, 200
Chiral symmetry and mesons in hot and dense matter: recent developments
We review recent results on properties of the meson gas relevant for Heavy
Ion Collision and Nuclear Matter experiments, within the framework of chiral
lagrangians. In particular, we describe the temperature and density evolution
of the and poles and its connection with chiral symmetry
restoration, as well as the chemical nonequilibrated phase and transport
coefficients.Comment: Proceedings of the "Chiral10 International Workshop on Chiral
Symmetry in Hadrons and Nuclei", Valencia, Spain, 21-24 june 2010. 9 pages, 5
figures. AIP Proceedings styl
Topological thermalization via vortex formation in ultra-fast quenches
We investigate the thermalization of a two-component scalar field across a
second-order phase transition under extremely fast quenches. We find that
vortices start developing at the final temperature of the quench, i.e., below
the critical point. Specifically, we find that vortices emerge once the
fluctuating field departures from its symmetric state and evolves towards a
metastable and inhomogenous configuration. The density of primordial vortices
at the relaxation time is a decreasing function of the final temperature of the
quench. Subsequently, vortices and antivortices annihilate at a rate that
eventually determines the total thermalization time. This rate decreases if the
theory contains a discrete anisotropy, which otherwise leaves the primordial
vortex density unaffected. Our results thus establish a link between the
topological processes involved in the vortex dynamics and the delay in the
thermalization of the system.Comment: 7 pages, 8 figures, 1 movie to be uploaded as Supplemental Material
in the published versio
Phase asymmetry effect in longitudinal offset coupled resonator optical waveguides
We show that the implementation of the longitudinal displacement technique
for adjusting the coupling coefficients in microring waveguides is subject to a
phase asymmetry effect. This issue is shown to substantially alter the system
response in apodized filters and cannot be ignored in the design stage
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