820 research outputs found
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Quarterly report, 1 May - 31 Aug. 1968
Mechanism of stress corrosion cracking in aluminum alloys and techniques for detection of surface defect
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Quarterly report, 1 Dec. 1967 - 29 Feb. 1968
Stress corrosion of aluminum alloys and techniques for its detectio
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Annual summary report, 2 Jun. 1967 - 1 Jun. 1968
Stress corrosion cracking of high strength aluminum alloys investigated by electrochemical, mechanical, and electron microscopic technique
Pairwise Discriminative Speaker Verification in the I-Vector Space
This work presents a new and efficient approach to discriminative speaker verification in the i-vector space. We illustrate the development of a linear discriminative classifier that is trained to discriminate between the hypothesis that a pair of feature vectors in a trial belong to the same speaker or to different speakers. This approach is alternative to the usual discriminative setup that discriminates between a speaker and all the other speakers. We use a discriminative classifier based on a Support Vector Machine (SVM) that is trained to estimate the parameters of a symmetric quadratic function approximating a log-likelihood ratio score without explicit modeling of the i-vector distributions as in the generative Probabilistic Linear Discriminant Analysis (PLDA) models. Training these models is feasible because it is not necessary to expand the i-vector pairs, which would be expensive or even impossible even for medium sized training sets. The results of experiments performed on the tel-tel extended core condition of the NIST 2010 Speaker Recognition Evaluation are competitive with the ones obtained by generative models, in terms of normalized Detection Cost Function and Equal Error Rate. Moreover, we show that it is possible to train a gender- independent discriminative model that achieves state-of-the-art accuracy, comparable to the one of a gender-dependent system, saving memory and execution time both in training and in testin
Breather decay into a vortex/anti-vortex pair in a Josephson Ladder
We present experimental evidence for a new behavior which involves discrete
breathers and vortices in a Josephson Ladder. Breathers can be visualized as
the creation and subsequent annihilation of vortex/anti-vortex pairs. An
externally applied magnetic field breaks the vortex/anti-vortex symmetry and
causes the breather to split apart. The motion of the vortex or anti-vortex
creates multi-site breathers, which are always to one side or the other of the
original breather depending on the sign of the applied field. This asymmetry in
applied field is experimentally observed.Comment: 10 pages, 5 figure
A Shift Symmetry in the Higgs Sector: Experimental Hints and Stringy Realizations
We interpret reported hints of a Standard Model Higgs boson at ~ 125 GeV in
terms of high-scale supersymmetry breaking with a shift symmetry in the Higgs
sector. More specifically, the Higgs mass range suggested by recent LHC data
extrapolates, within the (non-supersymmetric) Standard Model, to a vanishing
quartic Higgs coupling at a UV scale between 10^6 and 10^18 GeV. Such a small
value of lambda can be understood in terms of models with high-scale SUSY
breaking if the Kahler potential possesses a shift symmetry, i.e., if it
depends on H_u and H_d only in the combination (H_u+\bar{H}_d). This symmetry
is known to arise rather naturally in certain heterotic compactifications. We
suggest that such a structure of the Higgs Kahler potential is common in a
wider class of string constructions, including intersecting D7- and D6-brane
models and their extensions to F-theory or M-theory. The latest LHC data may
thus be interpreted as hinting to a particular class of compactifications which
possess this shift symmetry.Comment: v2: References added. v3: References added, published versio
Meta-stable SUSY Breaking Model in Supergravity
We analyze a supersymmetry (SUSY) breaking model proposed by Intriligator,
Seiberg and Shih in a supergravity (SUGRA) framework. This is a simple and
natural setup which demands neither extra superpotential interactions nor an
additional gauge symmetry. In the SUGRA setup, the U(1)R symmetry is explicitly
broken by the constant term in the superpotential, and pseudo-moduli field
naturally takes non-zero vacuum expectation value through a vanishing
cosmological constant condition. Sfermions tend to be heavier than gauginos,
and the strong-coupling scale is determined once a ratio of sfermion to gaugino
masses is fixed.Comment: 13 page
Meta-Stable Dynamical Supersymmetry Breaking Near Points of Enhanced Symmetry
We show that metastable supersymmetry breaking is generic near certain
enhanced symmetry points of gauge theory moduli spaces. Our model consists of
two sectors coupled by a singlet and combines dynamical supersymmetry breaking
with an O'Raifeartaigh mechanism in terms of confined variables. All relevant
mass parameters, including the supersymmetry breaking scale, are generated
dynamically. The metastable vacua appear as a result of a balance between
non-perturbative and perturbative quantum effects along a pseudo-runaway
direction.Comment: 27 pages, harvmac, 6 figure
Neutralino Dark Matter in Mirage Mediation
We study the phenomenology of neutralino dark matter (DM) in mirage mediation
scenario of supersymmetry breaking which results from the moduli stabilization
in some string/brane models. Depending upon the model parameters, especially
the anomaly to modulus mediation ratio determined by the moduli stabilization
mechanism, the nature of the lightest supersymmetric particle (LSP) changes
from Bino-like neutralino to Higgsino-like one via Bino-Higgsino mixing region.
For the Bino-like LSP, the standard thermal production mechanism can give a
right amount of relic DM density through the stop/stau-neutralino
coannihilation or the pseudo-scalar Higgs resonance process. We also examine
the prospect of direct and indirect DM detection in various parameter regions
of mirage mediation. Neutralino DM in galactic halo might be detected by near
future direct detection experiments in the case of Bino-Higgsino mixed LSP. The
gamma ray flux from Galactic Center might be detectable also if the DM density
profile takes a cuspy shape.Comment: One reference adde
The severity of Puumala hantavirus induced nephropathia epidemica can be better evaluated using plasma interleukin-6 than C-reactive protein determinations
<p>Abstract</p> <p>Background</p> <p>Nephropathia epidemica (NE) is a Scandinavian type of hemorrhagic fever with renal syndrome caused by Puumala hantavirus. The clinical course of the disease varies greatly in severity. The aim of the present study was to evaluate whether plasma C-reactive protein (CRP) and interleukin (IL)-6 levels associate with the severity of NE.</p> <p>Methods</p> <p>A prospectively collected cohort of 118 consecutive hospital-treated patients with acute serologically confirmed NE was examined. Plasma IL-6, CRP, and creatinine, as well as blood cell count and daily urinary protein excretion were measured on three consecutive days after admission. Plasma IL-6 and CRP levels higher than the median were considered high.</p> <p>Results</p> <p>We found that high IL-6 associated with most variables reflecting the severity of the disease. When compared to patients with low IL-6, patients with high IL-6 had higher maximum blood leukocyte count (11.9 <it>vs </it>9.0 Ă— 10<sup>9</sup>/l, <it>P </it>= 0.001) and urinary protein excretion (2.51 <it>vs </it>1.68 g/day, <it>P </it>= 0.017), as well as a lower minimum blood platelet count (55 <it>vs </it>80 Ă— 10<sup>9</sup>/l, <it>P </it>< 0.001), hematocrit (0.34 <it>vs </it>0.38, <it>P </it>= 0.001), and urinary output (1040 <it>vs </it>2180 ml/day, <it>P </it>< 0.001). They also stayed longer in hospital than patients with low IL-6 (8 <it>vs </it>6 days, <it>P </it>< 0.001). In contrast, high CRP did not associate with severe disease.</p> <p>Conclusions</p> <p>High plasma IL-6 concentrations associate with a clinically severe acute Puumala hantavirus infection, whereas high plasma CRP as such does not reflect the severity of the disease.</p
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