177,743 research outputs found
Data structures maxima
Projet EURECAThe purpose of this paper is to analyze the maxima properties (value and position) of some data structures. Our theorems concern the distribution of the random variables. Previously known results usually dealt with the mean and sometimes the variance of these random variables. Many of our results rely on diffusion techniques. That is a very powerful tool, which has already been used with some success in the analysis of algorithms
Simultaneous fine structure observation of wind and temperature profiles by the Arecibo 430-MHz radar and in situ measurements
A simultaneous campaign of balloon and radar measurements took place on March 14 to 16, 1984, above the Arecibo 430-MHz radar. This radar was operating with a vertical resolution of 150 m following two antenna beam directions: 15 deg. from the zenith, respectively, in the N-S and E-W directions. The main results concerning the comparison between the flight and simultaneous radar measurements obtained on March 15, 1984 are analyzed. The radar return power profile (S/N ratio in dB) exhibits maxima which are generally well correlated with step-like structures in the potential temperature profile. These structures are generally considered as the consequence of the mixing processes induced by the turbulence. A good correlation appears in the altitude range 12.5 to 19 km between wind shears induced by a wave structure observed in the meridional wind and the radar echo power maxima. This wave structure is characterized by a vertical wavelength of about 2.5 km, and a period in the range 30 to 40 hours. These characteristics are deduced from the twice daily rawinsonde data launched from the San Juan Airport by the National Weather Service. These results pointed out an example of the interaction between wave and turbulence in the upper troposphere and lower stratosphere. Turbulent layers are observed at locations where wind shears related to an internal inertia-gravity wave are maxima
Studying stellar binary systems with the Laser Interferometer Space Antenna using Delayed Rejection Markov chain Monte Carlo methods
Bayesian analysis of LISA data sets based on Markov chain Monte Carlo methods
has been shown to be a challenging problem, in part due to the complicated
structure of the likelihood function consisting of several isolated local
maxima that dramatically reduces the efficiency of the sampling techniques.
Here we introduce a new fully Markovian algorithm, a Delayed Rejection
Metropolis-Hastings Markov chain Monte Carlo method, to efficiently explore
these kind of structures and we demonstrate its performance on selected LISA
data sets containing a known number of stellar-mass binary signals embedded in
Gaussian stationary noise.Comment: 12 pages, 4 figures, accepted in CQG (GWDAW-13 proceedings
Spectroscopic evidence for temperature-dependent convergence of light and heavy hole valence bands of PbQ (Q=Te, Se, S)
We have conducted temperature dependent Angle Resolved Photoemission
Spectroscopy (ARPES) study of the electronic structures of PbTe, PbSe and PbS.
Our ARPES data provide direct evidence for the \emph{light} hole upper valence
bands (UVBs) and hitherto undetected \emph{heavy} hole lower valence bands
(LVBs) in these materials. An unusual temperature dependent relative movement
between these bands leads to a monotonic decrease in the energy separation
between their maxima with increasing temperature, which is referred as band
convergence and has long been believed to be the driving factor behind
extraordinary thermoelectric performances of these compounds at elevated
temperatures.Comment: 6 pages, 4 figures. arXiv admin note: text overlap with
arXiv:1404.180
Investigation of galactic alignment in LSC galaxy clusters
We investigate the galactic axes orientations within 18 selected clusters,
sub-structures of the Local Supercluster. For every cluster we map the
parameter \Delta_{11} (Flin & God{\l}owski 1986) describing the galactic axes
alignment with respect to a cluster pole changing along the entire celestial
sphere. The resulting maps are analyzed for correlations of its maxima with
directions from the cluster centre to 1.) the derived `physical' cluster poles,
2.) the Local Supercluster centre, 3.) the Virgo A centre and 4.) the Earth,
i.e. along the line of sight (LOS). The strong maxima - with one exception -
exist only for non-spiral (NS) sub-samples, with the maximum well correlated
with the LOS direction. For clusters with a clearly defined weak maximum the
conclusion generally does not change. For the spiral (S) sub-samples the maps
are usually at the random noise level. In these cases a weaker, but still
existent correlation with the LOS is observed and no other evident correlations
are noted. We conclude that the strong systematic effect, generated by the
process of galactic axis de-projection from its optical image, is present in
the catalogue data. With the use of a simple model for the systematic effect we
are able to reproduce the main characteristic features of the maps for NS
galaxies. We note, however, a few clusters showing significant differences with
respect to this model.Comment: LaTeX (21 pages, 10 gif figures); MNRAS, accepte
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