246 research outputs found
DSEARCH: sensitive database searching using distributed computing
Summary: We present a distributed and fully cross-platform database search program that allows the user to utilise the idle clock cycles of machines to perform large searches using the most sensitive algorithms. For those in an academic or corporate environment with hundreds
of idle desktop machines, DSEARCH can deliver a âfreeâ database search supercomputer.
Availability: The software is publicly available under the GNU general public licence from
http://www.cs.may.ie/distributed
Contact: [email protected]
Supplementary Information: Full documentation and a user manual is available from
http://www.cs.may.ie/distribute
Preliminary fan-blade design using intermediate response approximations
A midrange approximation method for design optimization is formulated. This utilizes intermediate response
variables, amenable to simple polynomial representation, to provide a reasonable approximation over a trust region.
It has applications to computationally expensive, nonlinear optimization problems where a designer’s knowledge
may be exploited to select appropriate intermediate variables. Application to the preliminary structural design of
a fan blade is illustrated in two case studies; results for a global optimization strategy and a direct search have
been included for comparison. Significant improvement in the number of function calls necessary to identify a
local optimum is demonstrated in the case studies considered
Building large phylogenetic trees on coarse-grained parallel machines
Phylogenetic analysis is an area of computational biology concerned
with the reconstruction of evolutionary relationships between organisms, genes,
and gene families. Maximum likelihood evaluation has proven to be one of the
most reliable methods for constructing phylogenetic trees. The huge computa-
tional requirements associated with maximum likelihood analysis means that it is
not feasible to produce large phylogenetic trees using a single processor. We have
completed a fully cross platform coarse grained distributed application, DPRml,
which overcomes many of the limitations imposed by the current set of parallel
phylogenetic programs. We have completed a set of efï¬ciency tests that show how
to maximise efï¬ciency while using the program to build large phylogenetic trees.
The software is publicly available under the terms of the GNU general public li-
cence from the system webpage at http://www.cs.nuim.ie/distribute
A research pathway for experimental psychopathology: the role of external validity criteria
This paper outlines a putative pathway for experimental psychopathology research developing psychological models of clinical disorders. The pathway uses established external validity criteria to define the pathway and clarifies the important role that research conducted on healthy participants can play in our understanding of clinical disorders. Defining a research pathway for experimental psychopathology in this way has a number of benefits It would (1) make explicit the need to address the external validity of developed models, (2) provide a clear set of criteria that would be required to extend research on healthy individuals to diagnostic populations, and (3) recommend using general psychological knowledge when developing models of psychopathology
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using
ultracold atoms in an optical lattice. We investigate the phase evolution of an
array of essentially non-interacting matter waves and observe matter-wave
collapse and revival in the form of a Talbot interference pattern. By using
long expansion times, we image momentum space with sub-recoil resolution,
allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure
Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at \snn=130 GeV
Mid-rapidity transverse mass spectra and multiplicity densities of charged
and neutral kaons are reported for Au+Au collisions at \snn=130 GeV at RHIC.
The spectra are exponential in transverse mass, with an inverse slope of about
280 MeV in central collisions. The multiplicity densities for these particles
scale with the negative hadron pseudo-rapidity density. The charged kaon to
pion ratios are and
for the most central collisions. The ratio is lower than the same
ratio observed at the SPS while the is higher than the SPS result.
Both ratios are enhanced by about 50% relative to p+p and +p
collision data at similar energies.Comment: 6 pages, 3 figures, 1 tabl
Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV
We present the first measurement of directed flow () at RHIC. is
found to be consistent with zero at pseudorapidities from -1.2 to 1.2,
then rises to the level of a couple of percent over the range . The latter observation is similar to data from NA49 if the SPS rapidities
are shifted by the difference in beam rapidity between RHIC and SPS.
Back-to-back jets emitted out-of-plane are found to be suppressed more if
compared to those emitted in-plane, which is consistent with {\it jet
quenching}. Using the scalar product method, we systematically compared
azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow
from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure
Azimuthal anisotropy: the higher harmonics
We report the first observations of the fourth harmonic (v_4) in the
azimuthal distribution of particles at RHIC. The measurement was done taking
advantage of the large elliptic flow generated at RHIC. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding
Partonic flow and -meson production in Au+Au collisions at = 200 GeV
We present first measurements of the -meson elliptic flow
() and high statistics distributions for different
centralities from = 200 GeV Au+Au collisions at RHIC. In
minimum bias collisions the of the meson is consistent with the
trend observed for mesons. The ratio of the yields of the to those of
the as a function of transverse momentum is consistent with a model
based on the recombination of thermal quarks up to GeV/,
but disagrees at higher momenta. The nuclear modification factor () of
follows the trend observed in the mesons rather than in
baryons, supporting baryon-meson scaling. Since -mesons are
made via coalescence of seemingly thermalized quarks in central Au+Au
collisions, the observations imply hot and dense matter with partonic
collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR
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