55,138 research outputs found
High p_T Triggered Delta-eta,Delta-phi Correlations over a Broad Range in Delta-eta
The first measurement of pseudorapidity (Delta-eta) and azimuthal angle
(Delta-phi) correlations between high transverse momentum charged hadrons (p_T
> 2.5 GeV/c) and all associated particles is presented at both short- (small
Delta-eta) and long-range (large Delta-eta) over a continuous pseudorapidity
acceptance (-4<Delta-eta<2). In these proceedings, the various near- and
away-side features of the correlation structure are discussed as a function of
centrality in Au+Au collisions measured by PHOBOS at sqrt(s_NN)=200 GeV. In
particular, this measurement allows a much more complete determination of the
longitudinal extent of the ridge structure, first observed by the STAR
collaboration over a limited eta range. In central collisions the ridge
persists to at least Delta-eta=4, diminishing in magnitude as collisions become
more peripheral until it disappears around Npart=80.Comment: 5 pages, 2 figures, presented at the 20th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur,
India, February 4-10, 2008. Full author list included and typo corrected in
equation
Pion Interferometry for a Granular Source of Quark-Gluon Plasma Droplets
We examine the two-pion interferometry for a granular source of quark-gluon
plasma droplets. The evolution of the droplets is described by relativistic
hydrodynamics with an equation of state suggested by lattice gauge results.
Pions are assumed to be emitted thermally from the droplets at the freeze-out
configuration characterized by a freeze-out temperature . We find that the
HBT radius decreases if the initial size of the droplets decreases.
On the other hand, depends on the droplet spatial distribution and
is relatively independent of the droplet size. It increases with an increase in
the width of the spatial distribution and the collective-expansion velocity of
the droplets. As a result, the value of can lie close to
for a granular quark-gluon plasma source. The granular model of the emitting
source may provide an explanation to the RHIC HBT puzzle and may lead to a new
insight into the dynamics of the quark-gluon plasma phase transition.Comment: 5 pages, 4 figure
Magnetic domain walls in constrained geometries
Magnetic domain walls have been studied in micrometer-sized Fe20Ni80 elements
containing geometrical constrictions by spin-polarized scanning electron
microscopy and numerical simulations. By controlling the constriction
dimensions, the wall width can be tailored and the wall type modified. In
particular, the width of a 180 degree Neel wall can be strongly reduced or
increased by the constriction geometry compared with the wall in unconstrained
systems.Comment: 4 pages, 6 figure
Information layering to de-clutter displays in emergency ambulance dispatch.
In this paper we report on a study to examine the usefulness of the MLD (Multi-Layered Display) as a device for creating physically distinct but visually overlapping information, what we refer to as 'information layering'. The technique was applied to emergency ambulance control, as a method for reducing visual clutter and information complexity in displays used by controllers. The results of the study show that participants completing simulated dispatch tasks in the MLD condition performed better on all categories of task difficulty compared to participants using a standard single layer display. However the improvements in performance were not significantly different
Interactive visualization for information analysis in medical diagnosis
This paper investigates to what extend the findings and solutions of information analysis in intelligence analysis can be applied and transferred into the medical diagnosis domains. Interactive visualization is proposed to address some of the problems faced by both domain. Its design issues related to selected common problems are then discussed in details. Finally, a visual sense making system INVISQUE is used as an example to illustrate how the interactive visualization can be used to support information analysis and medical diagnosis
Dyons of One Half Monopole Charge
We would like to present some exact SU(2) Yang-Mills-Higgs dyon solutions of
one half monopole charge. These static dyon solutions satisfy the first order
Bogomol'nyi equations and are characterized by a parameter, . They are
axially symmetric. The gauge potentials and the electromagnetic fields possess
a string singularity along the negative z-axis and hence they possess infinite
energy density along the line singularity. However the net electric charges of
these dyons which varies with the parameter are finite.Comment: 16 pages, 7 figure
The influence of the cluster environment on the star formation efficiency of 12 Virgo spiral galaxies
The influence of the environment on gas surface density and star formation
efficiency of cluster spiral galaxies is investigated. We extend previous work
on radial profiles by a pixel-to pixel analysis looking for asymmetries due to
environmental interactions. The star formation rate is derived from GALEX UV
and Spitzer total infrared data. As in field galaxies, the star formation rate
for most Virgo galaxies is approximately proportional to the molecular gas
mass. Except for NGC 4438, the cluster environment does not affect the star
formation efficiency with respect to the molecular gas. Gas truncation is not
associated with major changes in the total gas surface density distribution of
the inner disk of Virgo spiral galaxies. In three galaxies, possible increases
in the molecular fraction and the star formation efficiency with respect to the
total gas, of factors of 1.5 to 2, are observed on the windward side of the
galactic disk. A significant increase of the star formation efficiency with
respect to the molecular gas content on the windward side of ram
pressure-stripped galaxies is not observed. The ram-pressure stripped
extraplanar gas of 3 highly inclined spiral galaxies shows a depressed star
formation efficiency with respect to the total gas, and one of them (NGC 4438)
shows a depressed rate even with respect to the molecular gas. The
interpretation is that stripped gas loses the gravitational confinement and
associated pressure of the galactic disk, and the gas flow is diverging, so the
gas density decreases and the star formation rate drops. However, the stripped
extraplanar gas in one highly inclined galaxy (NGC 4569) shows a normal star
formation efficiency with respect to the total gas. We propose this galaxy is
different because it is observed long after peak pressure, and its extraplanar
gas is now in a converging flow as it resettles back into the disk.Comment: 34 pages, 24 figures, accepted for publication by A&
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