4,430 research outputs found
Metastable supersymmetry breaking and multitrace deformations of SQCD
Metastable vacua in supersymmetric QCD in the presence of single and
multitrace deformations of the superpotential are explored, with the aim of
obtaining an acceptable phenomenology. The metastable vacua appear at one loop,
have a broken R-symmetry, and a magnetic gauge group that is completely
Higgsed. With only a single trace deformation, the adjoint fermions from the
meson superfield are approximately massless at one loop, even though they are
massive at tree level and R-symmetry is broken. Consequently, if charged under
the standard model, they are unacceptably light. A multitrace quadratic
deformation generates fermion masses proportional to the deformation parameter.
Phenomenologically viable models of direct gauge mediation can then be
obtained, and some of their features are discussed.Comment: 33 pages, 3 figures. Added references and a commen
Measurement of Cable System Losses Using Time Domain and VLF Techinques
Presented at the Insulated Conductors Committee, San Antonio, Texas, October 26-29, 2008
The Seasonal Cycle and Interannual Variability in Stratospheric Temperatures and Links to the BrewerâDobson Circulation: An Analysis of MSU and SSU Data
Previous studies have shown that lower-stratosphere temperatures display a near-perfect cancellation between tropical and extratropical latitudes on both annual and interannual time scales. The out-of-phase relationship between tropical and high-latitude lower-stratospheric temperatures is a consequence of variability in the strength of the BrewerâDobson circulation (BDC). In this study, the signal of the BDC in stratospheric temperature variability is examined throughout the depth of the stratosphere using data from the Stratospheric Sounding Unit (SSU). While the BDC has a seemingly modest signal in the annual cycle in zonal-mean temperatures in the mid- and upper stratosphere, it has a pronounced signal in the month-to-month and interannual variability. Tropical and extratropical temperatures are significantly negatively correlated in all SSU channels on interannual time scales, suggesting that variations in wave driving are a major factor controlling global-scale temperature variability not only in the lower stratosphere (as shown in previous studies), but also in the mid- and upper stratosphere. The out-of-phase relationship between tropical and high latitudes peaks at all levels during the cold-season months: DecemberâMarch in the Northern Hemisphere and JulyâOctober in the Southern Hemisphere. In the upper stratosphere, the out-of-phase relationship with high-latitude temperatures extends beyond the tropics and well into the extratropics of the opposite hemisphere. The seasonal cycle in stratospheric temperatures follows the annual march of insolation at all levels and latitudes except in the mid- to upper tropical stratosphere, where it is dominated by the semiannual oscillation. M
Predicting Dust Distribution in Protoplanetary Discs
We present the results of three-dimensional numerical simulations that
include the effects of hydrodynamical forces and gas drag upon an evolving
dusty gas disk. We briefly describe a new parallel, two phase numerical code
based upon the smoothed particle hydrodynamics (SPH) technique in which the gas
and dust phases are represented by two distinct types of particles. We use the
code to follow the dynamical evolution of a population of grains in a gaseous
protoplanetary disk in order to understand the distribution of grains of
different sizes within the disk. Our ``grains'' range from metre to
submillimetre in size.Comment: 2 pages, LaTeX with 1 ps figure embedded, using newpasp.sty
(supplied). To appear in the proceedings of the XIXth IAP colloquium
"Extrasolar Planets: Today and Tomorrow" held in Paris, France, 2003, June 30
-- July 4, ASP Conf. Se
Joint density-functional theory for electronic structure of solvated systems
We introduce a new form of density functional theory for the {\em ab initio}
description of electronic systems in contact with a molecular liquid
environment. This theory rigorously joins an electron density-functional for
the electrons of a solute with a classical density-functional theory for the
liquid into a single variational principle for the free energy of the combined
system. A simple approximate functional predicts, without any fitting of
parameters to solvation data, solvation energies as well as state-of-the-art
quantum-chemical cavity approaches, which require such fitting.Comment: Fixed typos and minor updates to tex
Running gait modifications can lead to immediate reductions in patellofemoral pain
Gait modifications are commonly advocated to decrease knee forces and pain in runners with patellofemoral pain (PFP). However, it remains unknown if clinicians can expect immediate effects on symptoms. Our objectives were (1) to compare the immediate effects of gait modifications on pain and kinetics of runners with PFP; (2) to compare kinetic changes in responders and non-responders; and (3) to compare the effects between rearfoot strikers (RFS) and non-RFS. Sixty-eight runners with PFP (42 women, 26 men) ran normally on a treadmill before testing six modifications: 1- increase step rate by 10%; 2- 180 steps per minute; 3- decrease step rate by 10%; 4- forefoot striking; 5- heel striking; 6- running softer. Overall, there were more responders (pain decreased â„1/10 compared with normal gait) during forefoot striking and increasing step rate by 10% (both 35%). Responders showed greater reductions in peak patellofemoral joint force than non-responders during all conditions except heel striking. When compared with non-RFS, RFS reduced peak patellofemoral joint force in a significant manner (Pâ<â0.001) during forefoot striking (partial η2â=â0.452) and running softer (partial η2â=â0.302). Increasing step rate by 10% reduced peak patellofemoral joint force in both RFS and non-RFS. Forty-two percent of symptomatic runners reported immediate reductions in pain during â„1 modification, and 28% had reduced pain during â„3 modifications. Gait modifications leading to decreased patellofemoral joint forces may be associated with immediate pain reductions in runners with PFP. Other mechanisms may be involved, given that some runners reported decreased symptoms regardless of kinetic changes
Decreased expression of caveolin 1 in patients with systemic sclerosis: crucial role in the pathogenesis of tissue fibrosis.
OBJECTIVE: Recent studies have implicated caveolin 1 in the regulation of transforming growth factor beta (TGFbeta) downstream signaling. Given the crucial role of TGFbeta in the pathogenesis of systemic sclerosis (SSc), we sought to determine whether caveolin 1 is also involved in the pathogenesis of tissue fibrosis in SSc. We analyzed the expression of CAV1 in affected SSc tissues, studied the effects of lack of expression of CAV1 in vitro and in vivo, and analyzed the effects of restoration of caveolin 1 function on the fibrotic phenotype of SSc fibroblasts in vitro.
METHODS: CAV1 expression in tissues was analyzed by immunofluorescence and confocal microscopy. The extent of tissue fibrosis in Cav1-knockout mice was assessed by histologic/histochemical analyses and quantified by hydroxyproline assays. Cav1-null and SSc fibroblast phenotypes and protein production were analyzed by real-time polymerase chain reaction, immunofluorescence, Western blot, and multiplexed enzyme-linked immunosorbent assay techniques. The effects of restoration of caveolin 1 function in SSc fibroblasts in vitro were also examined using a cell-permeable recombinant CAV1 peptide.
RESULTS: CAV1 was markedly decreased in the affected lungs and skin of SSc patients. Cav1-knockout mice developed pulmonary and skin fibrosis. Down-regulation of caveolin 1 was maintained in cultured SSc fibroblasts, and restoration of caveolin 1 function in vitro normalized their phenotype and abrogated TGFbeta stimulation through inhibition of Smad3 activation.
CONCLUSION: Caveolin 1 appears to participate in the pathogenesis of tissue fibrosis in SSc. Restoration of caveolin 1 function by treatment with a cell-permeable peptide corresponding to the CAV1 scaffolding domain may be a novel therapeutic approach in SSc
A compilation of digitized satellite imagery of the Gulf Stream (1982, 1983, and 1985)
Ninety plots of digitized temperature boundaries from infared satellite images
of the Gulf Stream along with corresponding image snapshots were compiled to
determine stream width propagation speed. The satellite images are from the years
1982, 1983, and 1985 and are often of consecutive days. In this report, these images
and digitized plots are presented.Funding was provided by the Office of Naval Research
through contract Number N00014-87-K-0007, and
by the National Science Foundation under grant Numbers
OCE 87-00601 and OCE 85-10828
Conductivity and the current-current correlation measure
We review various formulations of conductivity for one-particle Hamiltonians
and relate them to the current-current correlation measure. We prove that the
current-current correlation measure for random Schr\"odinger operators has a
density at coincident energies provided the energy lies in a localization
regime. The density vanishes at such energies and an upper bound on the rate of
vanishing is computed. We also relate the current-current correlation measure
to the localization length
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