21,598 research outputs found
Dutch listeners' use of suprasegmental cues to English stress
Dutch listeners outperform native listeners in identifying syllable stress in English. This is because lexical stress is more useful in recognition of spoken words of Dutch than of English, so that Dutch listeners pay greater attention to stress in general. We examined Dutch listeners’ use of the acoustic correlates of English stress. Primary- and secondary-stressed syllables differ significantly on acoustic measures, and some differences, in F0 especially, correlate with data of earlier listening experiments. The correlations found in the Dutch responses were not paralleled in data from native listeners. Thus the acoustic cues which distinguish English primary versus secondary stress are better exploited by Dutch than by native listeners
Deep spectroscopic luminosity function of Abell 85: no evidence for a steep upturn of the faint-end slope
We present a new deep determination of the spectroscopic LF within the virial
radius of the nearby and massive Abell\,85 (A85) cluster down to the dwarf
regime (M* + 6) using VLT/VIMOS spectra for galaxies with m mag and mag arcsec. The
resulting LF from 438 cluster members is best modelled by a double Schechter
function due to the presence of a statistically significant upturn at the
faint-end. The amplitude of this upturn (),
however, is much smaller than that of the SDSS composite photometric cluster LF
by Popesso et al. 2006, -2. The faint-end slope of the LF in
A85 is consistent, within the uncertainties, with that of the field. The red
galaxy population dominates the LF at low luminosities, and is the main
responsible for the upturn. The fact that the slopes of the spectroscopic LFs
in the field and in a cluster as massive as A85 are similar suggests that the
cluster environment does not play a major role in determining the abundance of
low-mass galaxies.Comment: 6 pages, 4 figures, accepted at MNRAS lette
Robust and Efficient Uncertainty Quantification and Validation of RFIC Isolation
Modern communication and identification products impose demanding constraints on reliability of components. Due to this statistical constraints more and more enter optimization formulations of electronic products. Yield constraints often require efficient sampling techniques to obtain uncertainty quantification also at the tails of the distributions. These sampling techniques should outperform standard Monte Carlo techniques, since these latter ones are normally not efficient enough to deal with tail probabilities. One such a technique, Importance Sampling, has successfully been applied to optimize Static Random Access Memories (SRAMs) while guaranteeing very small failure probabilities, even going beyond 6-sigma variations of parameters involved. Apart from this, emerging uncertainty quantifications techniques offer expansions of the solution that serve as a response surface facility when doing statistics and optimization. To efficiently derive the coefficients in the expansions one either has to solve a large number of problems or a huge combined problem. Here parameterized Model Order Reduction (MOR) techniques can be used to reduce the work load. To also reduce the amount of parameters we identify those that only affect the variance in a minor way. These parameters can simply be set to a fixed value. The remaining parameters can be viewed as dominant. Preservation of the variation also allows to make statements about the approximation accuracy obtained by the parameter-reduced problem. This is illustrated on an RLC circuit. Additionally, the MOR technique used should not affect the variance significantly. Finally we consider a methodology for reliable RFIC isolation using floor-plan modeling and isolation grounding. Simulations show good comparison with measurements
Photon noise limited radiation detection with lens-antenna coupled Microwave Kinetic Inductance Detectors
Microwave Kinetic Inductance Detectors (MKIDs) have shown great potential for
sub-mm instrumentation because of the high scalability of the technology. Here
we demonstrate for the first time in the sub-mm band (0.1...2 mm) a photon
noise limited performance of a small antenna coupled MKID detector array and we
describe the relation between photon noise and MKID intrinsic
generation-recombination noise. Additionally we use the observed photon noise
to measure the optical efficiency of detectors to be 0.8+-0.2.Comment: The following article has been submitted to AP
Non-Abelian Giant Gravitons
We argue that the giant graviton configurations known from the literature
have a complementary, microscopical description in terms of multiple
gravitational waves undergoing a dielectric (or magnetic moment) effect. We
present a non-Abelian effective action for these gravitational waves with
dielectric couplings and show that stable dielectric solutions exist. These
solutions agree in the large limit with the giant graviton configurations
in the literature.Comment: 8 pages. Contribution to the proceedings of the RTN workshop in
Leuven, Belgium, September 200
The relation between bar formation, galaxy luminosity, and environment
We derive the bar fraction in three different environments ranging from the
field to Virgo and Coma clusters, covering an unprecedentedly large range of
galaxy luminosities (or, equivalently, stellar masses). We confirm that the
fraction of barred galaxies strongly depends on galaxy luminosity. We also show
that the difference between the bar fraction distributions as a function of
galaxy luminosity (and mass) in the field and Coma cluster are statistically
significant, with Virgo being an intermediate case. We interpret this result as
a variation of the effect of environment on bar formation depending on galaxy
luminosity. We speculate that brighter disk galaxies are stable enough against
interactions to keep their cold structure, thus, the interactions are able to
trigger bar formation. For fainter galaxies the interactions become strong
enough to heat up the disks inhibiting bar formation and even destroying the
disks. Finally, we point out that the controversy regarding whether the bar
fraction depends on environment could be resolved by taking into account the
different luminosity ranges of the galaxy samples studied so far.Comment: 4 pages, 2 figures. To appear in the proceedings of EWASS 2012
Special Session 4, Structure of galaxy disks shaped by secular evolution and
environmental processes, ed. P. Di Matteo and C. Jog, Memorie della Societ\`a
Astronomica Italiana Supplement Serie
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