13,040 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
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
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
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
Fast and slow light in zig-zag microring resonator chains
We analyze fast and slow light transmission in a zig-zag microring resonator
chain. This novel device permits the operation in both regimes. In the
superluminal case, a new ubiquitous light transmission effect is found whereby
the input optical pulse is reproduced in an almost simultaneous manner at the
various system outputs. When the input carrier is tuned to a different
frequency, the system permits to slow down the propagating optical signal.
Between these two extreme cases, the relative delay can be tuned within a broad
range
L-selectin and beta(2)-integrin expression on circulating bovine polymorphonuclear leukocytes during endotoxin mastitis
The aim of this in vivo study was to examine the effect of intramammarily administered endotoxin (lipopolysaccharide, LPS) on the expression of L-selectin (CD62L) and the beta(2)-integrin subunits CD11b and CD18 on circulating bovine PMN. Six early lactating cows were infused with Escherichia coli LPS. The adhesion molecules under study were stained at the cell surface and analyzed flow cytometrically. In addition, some of the clinical parameters associated with adhesion molecule mobilization such as fever, blood cortisol levels, somatic cell count (SCC), and total and differential blood leukocyte count were measured. In analogy with observations during clinical coliform mastitis, a progressive decrease of CD62L expression levels was observed early after LPS infusion, concomitantly with a continuous rise of CD11b and CD18 density. However, no correlation was found between the kinetics of CD11b and CD18 density. The initial changes in adhesion molecule expression paralleled the decrease in blood PMN numbers, together with the increase in rectal temperature, cortisol levels, SCC, and number of circulating immature PMN. In conclusion, intramammarily administered LPS seems to play an important role in modulating adhesion receptor expression on circulating bovine PMN. Interestingly, in contrast to coliform mastitis, the net CD18 variation is not principally influenced by CD11b upregulation during endotoxin administration. The knowledge of adhesion molecule kinetics in relation to the different parameters evaluated in the present study contributes to an improved understanding of the inflammatory reaction
The calcium-sensing receptor as a regulator of cellular fate in normal and pathological conditions
The calcium-sensing receptor (CaSR) belongs to the evolutionarily conserved family of plasma membrane G protein-coupled receptors (GPCRs). Early studies identified an essential role for the CaSR in systemic calcium homeostasis through its ability to sense small changes in circulating calcium concentration and to couple this information to intracellular signaling pathways that influence parathyroid hormone secretion. However, the presence of CaSR protein in tissues is not directly involved in regulating mineral ion homeostasis points to a role for the CaSR in other cellular functions including the control of cellular proliferation, differentiation and apoptosis. This position at the crossroads of cellular fate designates the CaSR as an interesting study subject is likely to be involved in a variety of previously unconsidered human pathologies, including cancer, atherosclerosis and Alzheimer's disease. Here, we will review the recent discoveries regarding the relevance of CaSR signaling in development and disease. Furthermore, we will discuss the rational for developing and using CaSR-based therapeutics
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