11,862 research outputs found
Transverse momentum spectra and elliptic flow: Hydrodynamics with QCD-based equations of state
We present a family of equations of state within a quasiparticle model
adjusted to lattice QCD and study the impact on azimuthal flow anisotropies and
transverse momentum spectra within hydrodynamic simulations for heavy-ion
collisions at energies relevant for LHC.Comment: Aug. 2007. 3 pp. Talk given at the Focus Week of the workshop Heavy
Ion Collisions at the LHC - Last Call for Predictions, Genf, Switzerland, 29
May - 2 June 200
Jet trails and Mach cones: The interaction of microquasars with the ISM
A sub-set of microquasars exhibit high peculiar velocity with respect to the
local standard of rest due to the kicks they receive when being born in
supernovae. The interaction between the radio plasma released by microquasar
jets from such high-velocity binaries with the ISM must lead to the production
of trails and bow shocks similar to what is observed in narrow-angle tailed
radio galaxies and pulsar wind nebulae. We present a set of numerical
simulations of this interaction that illuminate the long term dynamical
evolution and the observational properties of these microquasar bow shock
nebulae and trails. We find that this interaction always produces a structure
that consists of a bow shock, a trailing neck, and an expanding bubble. Using
our simulations to model emission, we predict that the shock surrounding the
bubble and the neck should be visible in H{\alpha} emission, the interior of
the bubble should be visible in synchrotron radio emission, and only the bow
shock is likely to be detectable in X-ray emission. We construct an analytic
model for the evolution of the neck and bubble shape and compare this model
with observations of X-ray binary SAX J1712.6-3739.Comment: 33 pages, 13 figures, 1 table; Accepted to Ap
Toward parton equilibration with improved parton interaction matrix elements
The Quark-Gluon Plasma can be produced in high energy heavy ion collisions
and how it equilibrates is important for the extraction of the properties of
strongly interacting matter. A radiative transport model can be used to reveal
interesting characteristics of Quark-Gluon Plasma thermalization. For example,
screened parton interactions always lead to partial pressure isotropization.
Systems with different initial pressure anisotropies evolve toward the same
asymptotic evolution. In particular, radiative processes are crucial for the
chemical equilibration of the system. Matrix elements under the soft and
collinear approximation for these processes, as first derived by Gunion and
Bertsch, are widely used. A different approach is to start with the exact
matrix elements for the two to three and its inverse processes. General
features of this approach will be reviewed and the results will be compared
with the Gunion-Bertsch results. We will comment on the possible implications
of the exact matrix element approach on Quark-Gluon Plasma thermalization.Comment: Presented at the 11th International Conference on Nucleus-Nucleus
Collisions (NN2012), San Antonio, Texas, USA, 27 May-1 June 201
Clinical relevance and treatment possibilities of bipolar rapid cycling
Bipolar rapid cycling (RC) is defined as 4 or more affective episodes within 1 year. It has been postulated that RC is related to a poor response to lithium, to the same extent as mixed episodes or other atypical symptoms of the illness. This article reviews the current status of alternative pharmacological or otherwise supportive therapies of RC. Biological parameters and characteristics of the illness associated with RC like gender prevalence in women, hyperthyroid ism, catecholamine-O-methyltransferase allele, the influence of sleep, different subtypes of bipolar disorder and the risk of antidepressant-induced cycling will be discussed in detail. Copyright (C) 2002 S. Karger AG, Basel
Clozapine as add-on medication in the maintenance treatment of bipolar and schizoaffective disorders - A case series
Atypical neuroleptics are increasingly used in the treatment of bipolar and schizoaffective disorders. Currently, numerous controlled short-term studies are available for clozapine, olanzapine, risperidone or quetiapine, but long-term data are still missing. Three patients (2 with bipolar disorder, 1 with schizoaffective disorder) are described who showed a marked reduction of affective symptomatology after clozapine had been added to mood stabilizer pretreatment. The patients were seen once a month before and after the introduction of clozapine for at least 6 months. Treatment response was evaluated using different rating scales (IDS, YMRS; GAF; CGIBP) and the NIMH Life Chart Methodology. All patients showed a marked improvement after the add-on treatment with clozapine had been initiated. Clozapine was tolerated well with only transient and moderate weight gain and fatigue as only side effects. This case series underlines the safety and efficacy of clozapine as add-on medication in the treatment of bipolar and schizoaffective disorders. Copyright (C) 2002 S. Karger AG, Basel
Projected Three-Pion Correlation Functions
We propose a new procedure for constructing projected three-pion correlation
functions which reduces undesirable artificial momentum dependences resulting
from the commonly used procedure and facilitates comparison of three-pion
correlation data with theoretical models.Comment: 6 pages revtex, incl. 1 figure. Submitted as Brief Report to Physical
Review C. Normalization error and typos correcte
Radial flow afterburner for event generators and the baryon puzzle
A simple afterburner including radial flow to the randomized transverse
momentum obtained from event generators, Pythia and Hijing, has been
implemented to calculate the ratios and compare them with available
data. A coherent trend of qualitative agreement has been obtained in
collisions and in for various centralities. Those results indicate that
the radial flow does play an important role in the so called baryon puzzle
anomaly.Comment: 11 pages, 5 figures. To appear in Journal of Physics
Yano-Koonin-Podgoretskii Parametrisation of the Hanbury Brown-Twiss Correlator
The Yano-Koonin-Podgoretskii (YKP) parametrisation of Hanbury Brown-Twiss
(HBT) two-particle correlation functions opens new strategies for extracting
the emission duration and testing the longitudinal expansion in heavy-ion
collisions. Based on the recently derived model-independent expressions, we
present a detailed parameter study of the YKP parameters for a finite,
hydrodynamically expanding source model of heavy-ion collisions. For the class
of models studied here, we show that the three YKP radius parameters have an
interpretation as longitudinal extension, transverse extension and emission
duration of the source in the YKP frame. This frame is specified by the fourth
fit parameter, the Yano-Koonin velocity which describes to a good approximation
the velocity of the fluid element with highest emissivity and allows to test
for the longitudinal expansion of the source. Deviations from this
interpretation of the YKP parameters are discussed quantitatively.Comment: 38 pages, REVTeX, 11 PS-figures, to be published in Z.Phys.
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