50,320 research outputs found
The impact of visual cues and lexical knowledge on the perception of a non-native consonant contrast for Colombian adults
The study investigates the impact of visual cues and lexical knowledge on the identification of a nonnative
phonemic contrast. Twenty native Colombians were tested on an identification task involving 16
minimal pairs of English words, produced by four English speakers, contrasting in the presence of /b/ or /v/
in initial or medial position. The test was run in three conditions: audiovisual (AV), audio only (A) or visual
only (V). Prior to the identification task, their knowledge of the lexical items was evaluated; they were also
recorded while reading the words. Mean identification scores were higher for the AV than the A condition,
but V and AV scores not differ. Relative to previous /b/-/v/ studies with Peninsular Spanish speakers,
Colombians relied more heavily on visual cues in their identification of /b/-/v/. Although there was a trend
for identification scores to be higher for known lexical items, this effect was not statistically significant.
Finally, production accuracy for the /b/-/v/ contrast was not correlated with perception accuracy, but
production tended to be more accurate in speakers with better lexical knowledge. The visual weighting
results suggest that the degree of visual bias in speech perception may be ‘culture-specific’ rather than
merely ‘language-specific’
Multi-GeV Neutrino Emission from Magnetized Gamma Ray Bursts
We investigate the expected neutrino emissivity from nuclear collisions in
magnetically dominated collisional models of gamma-ray bursts, motivated by
recent observational and theoretical developments. The results indicate that
significant multi-GeV neutrino fluxes are expected for model parameter values
which are typical of electromagnetically detected bursts. We show that for
detecting at least one muon event in Icecube and its Deep Core sub-array, a
single burst must be near the high end of the luminosity function and at a
redshift . We also calculate the luminosity and distance ranges
that can generate muon events per GRB in the same detectors, which may
be of interest if simultaneously detected electromagnetically, or if measured
with future extensions of Icecube or other neutrino detectors with larger
effective volume and better sensitivity.Comment: 12 pages, 7 figures, accepted version for Phys.Rev.
Denervation-induced activation of the standard proteasome and immunoproteasome
The standard 26S proteasome is responsible for the majority of myofibrillar protein degradation leading to muscle atrophy. The immunoproteasome is an inducible form of the proteasome. While its function has been linked to conditions of atrophy, its contribution to muscle proteolysis remains unclear. Therefore, the purpose of this study was to determine if the immunoproteasome plays a role in skeletal muscle atrophy induced by denervation. Adult male C57BL/6 wild type (WT) and immunoproteasome knockout lmp7-/-/mecl-1-/- (L7M1) mice underwent tibial nerve transection on the left hindlimb for either 7 or 14 days, while control mice did not undergo surgery. Proteasome activity (caspase-, chymotrypsin-, and trypsin- like), protein content of standard proteasome (β1, β5 and β2) and immunoproteasome (LMP2, LMP7 and MECL-1) catalytic subunits were determined in the gastrocnemius muscle. Denervation induced significant atrophy and was accompanied by increased activities and protein content of the catalytic subunits in both WT and L7M1 mice. Although denervation resulted in a similar degree of muscle atrophy between strains, the mice lacking two immunoproteasome subunits showed a differential response in the extent and duration of proteasome features, including activities and content of the β1, β5 and LMP2 catalytic subunits. The results indicate that immunoproteasome deficiency alters the proteasome's composition and activities. However, the immunoproteasome does not appear to be essential for muscle atrophy induced by denervation.T32 AG029796 - NIA NIH HH
Effective Field Theory for Rydberg Polaritons
We develop an effective field theory (EFT) to describe the few- and many-body
propagation of one dimensional Rydberg polaritons. We show that the photonic
transmission through the Rydberg medium can be found by mapping the propagation
problem to a non-equilibrium quench, where the role of time and space are
reversed. We include effective range corrections in the EFT and show that they
dominate the dynamics near scattering resonances in the presence of deep bound
states. Finally, we show how the long-range nature of the Rydberg-Rydberg
interactions induces strong effective -body interactions between Rydberg
polaritons. These results pave the way towards studying non-perturbative
effects in quantum field theories using Rydberg polaritons.Comment: 5+ pages main text, 3 figures; 5 pages supplemental, 1 figure; v2 -
replaced discussion of N-body bound state preparation with discussion of
effective range corrections and made other minor correction
A random number generator for continuous random variables
A FORTRAN 4 routine is given which may be used to generate random observations of a continuous real valued random variable. Normal distribution of F(x), X, E(akimas), and E(linear) is presented in tabular form
The relationship between induced fluid structure and boundary slip in nanoscale polymer films
The molecular mechanism of slip at the interface between polymer melts and
weakly attractive smooth surfaces is investigated using molecular dynamics
simulations. In agreement with our previous studies on slip flow of
shear-thinning fluids, it is shown that the slip length passes through a local
minimum at low shear rates and then increases rapidly at higher shear rates. We
found that at sufficiently high shear rates, the slip flow over atomically flat
crystalline surfaces is anisotropic. It is demonstrated numerically that the
friction coefficient at the liquid-solid interface (the ratio of viscosity and
slip length) undergoes a transition from a constant value to the power-law
decay as a function of the slip velocity. The characteristic velocity of the
transition correlates well with the diffusion velocity of fluid monomers in the
first fluid layer near the solid wall at equilibrium. We also show that in the
linear regime, the friction coefficient is well described by a function of a
single variable, which is a product of the magnitude of surface-induced peak in
the structure factor and the contact density of the adjacent fluid layer. The
universal relationship between the friction coefficient and induced fluid
structure holds for a number of material parameters of the interface: fluid
density, chain length, wall-fluid interaction energy, wall density, lattice
type and orientation, thermal or solid walls.Comment: 33 pages, 14 figure
Orientation filtering by growth-velocity competition in zone-melting recrystallization of silicon on SiO_2
We describe a method of controlling the in-plane directions of grains in (100)-textured silicon films produced by zone-melting recrystallization over amorphous SiO2. Grains having in-plane orientation within a narrow range are able to grow through an orientation filter consisting of a pattern of crystallization barriers, while grains having other orientations are occluded. The results of experiments using an orientation filter, and the parameters which optimize filter performance, are reported
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