17 research outputs found
Constraints on possible phase transitions above the nuclear saturation density
We compare different models for hadronic and quark phases of cold baryon-rich
matter in an attempt to find a deconfinement phase transition between them. For
the hadronic phase we consider Walecka-type mean-field models which describe
well the nuclear saturation properties. We also use the variational chain model
which takes into account correlation effects. For the quark phase we consider
the MIT bag model, the Nambu-Jona-Lasinio and the massive quasiparticle models.
By comparing pressure as a function of baryon chemical potential we find that
crossings of hadronic and quark branches are possible only in some exceptional
cases while for most realistic parameter sets these branches do not cross at
all. Moreover, the chiral phase transition, often discussed within the
framework of QCD motivated models, lies in the region where the quark phases
are unstable with respect to the hadronic phase. We discuss possible physical
consequences of these findings.Comment: 28 pages, 18 PostScript figures, submitted to Phys. Rev.
Space-time evolution and HBT analysis of relativistic heavy ion collisions in a chiral SU(3) x SU(3) model
The space-time dynamics and pion-HBT radii in central heavy ion-collisions at
CERN-SPS and BNL-RHIC are investigated within a hydrodynamic simulation. The
dependence of the dynamics and the HBT-parameters on the EoS is studied with
different parametrisations of a chiral SU(3) sigma-omega model. The
selfconsistent collective expansion includes the effects of effective hadron
masses, generated by the nonstrange and strange scalar condensates. Different
chiral EoS show different types of phase transitions and even a crossover. The
influence of the order of the phase transition and of the difference in the
latent heat on the space-time dynamics and pion-HBT radii is studied. A small
latent heat, i.e. a weak first-order chiral phase transition, or even a smooth
crossover leads to distinctly different HBT predictions than a strong first
order phase transition. A quantitative description of the data, both at SPS
energies as well as at RHIC energies, appears difficult to achieve within the
ideal hydrodynamical approach using the SU(3) chiral EoS. A strong first-order
quasi-adiabatic chiral phase transition seems to be disfavored by the pion-HBT
data from CERN-SPS and BNL-RHIC
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
Extensive experimental data from high-energy nucleus-nucleus collisions were
recorded using the PHENIX detector at the Relativistic Heavy Ion Collider
(RHIC). The comprehensive set of measurements from the first three years of
RHIC operation includes charged particle multiplicities, transverse energy,
yield ratios and spectra of identified hadrons in a wide range of transverse
momenta (p_T), elliptic flow, two-particle correlations, non-statistical
fluctuations, and suppression of particle production at high p_T. The results
are examined with an emphasis on implications for the formation of a new state
of dense matter. We find that the state of matter created at RHIC cannot be
described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted
to Nuclear Physics A as a regular article; v3 has minor changes in response
to referee comments. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
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POLARIZATION IN PROTON-PROTON SCATTERING USING A POLARIZED TARGET. Part I. 0.330 to 0.740 GeV Part II 1.70 to 6.15 GeV
Using the Berkeley polarized-proton target, we have measured the polarization parameter P({theta}) for proton-proton (p-p) scattering. The measurements were obtained at beam kinetic energies of 0.330, 0.680, and 0.740 GeV at the 184-in. synchrocyclotron and 1.70, 2.85, 3.50, 4.00, 5.05, and 6.15 GeV at the Bevatron. The angular regions measured were from 20 to 100 degrees center of mass; the square of the four-momentum transfer ranged from 0.1 to 0.8 (GeV/c){sup 2}
The impact of ideas and time on policy solutions: Maintaining institutional autonomy and the second runway at Manchester Airport
The important interrelationships between problems, ideas and time mean that there can be several facets to institutional vulnerability. Thus conditions at a moment in time can make an institution open to the introduction of new ideas, but these ideas may compete over time. In this context, a policy problem may demand a solution that satisfies the immediate situation, but can find itself overtaken by the effects of time. The case study examines an environmental mitigation package signed in association with construction of the second runway at Manchester Airport. The instrument attempted to deal with two competing ideas in the form of economic growth and sustainable development. However, economic growth was firmly grounded in the institutional strength of the Airport, while the demands of sustainable development required careful management over time. The article concludes that time emerges as a powerful variable in shifting the terms of the policy debate. © Blackwell Publishing Ltd. 2005
Soluble epoxide hydrolase is a susceptibility factor for heart failure in a rat model of human disease
We aimed to identify genetic variants associated with heart failure by using a rat model of the human disease. We performed invasive cardiac hemodynamic measurements in F(2) crosses between spontaneously hypertensive heart failure (SHHF) rats and reference strains. We combined linkage analyses with genome-wide expression profiling and identified Ephx2 as a heart failure susceptibility gene in SHHF rats. Specifically, we found that cis variation at Ephx2 segregated with heart failure and with increased transcript expression, protein expression and enzyme activity, leading to a more rapid hydrolysis of cardioprotective epoxyeicosatrienoic acids. To confirm our results, we tested the role of Ephx2 in heart failure using knockout mice. Ephx2 gene ablation protected from pressure overload-induced heart failure and cardiac arrhythmias. We further demonstrated differential regulation of EPHX2 in human heart failure, suggesting a cross-species role for Ephx2 in this complex disease
Supplementary Material for: Stress Response to the Functional Magnetic Resonance Imaging Environment in Healthy Adults Relates to the Degree of Limbic Reactivity during Emotion Processing
<p><b><i>Background:</i></b> Imaging techniques are increasingly being
used to examine the neural correlates of stress and emotion processing;
however, relations between the primary stress hormone cortisol, the
functional magnetic resonance imaging (fMRI) environment, and individual
differences in response to emotional challenges are not yet well
studied. The present study investigated whether cortisol activity prior
to, and during, an fMRI scan may be related to neural processing of
emotional information. <b><i>Methods:</i></b> Twenty-six healthy individuals (10 female) completed a facial emotion perception test during 3-tesla fMRI. <b><i>Results:</i></b>
Prescan cortisol was significantly correlated with enhanced amygdala,
hippocampal, and subgenual cingulate reactivity for facial recognition.
Cortisol change from pre- to postscanning predicted a greater activation
in the precuneus for both fearful and angry faces. A negative
relationship between overall face accuracy and activation in limbic
regions was observed. <b><i>Conclusion:</i></b> Individual differences
in response to the fMRI environment might lead to a greater
heterogeneity of brain activation in control samples, decreasing the
power to detect differences between clinical and comparison groups.</p
Soluble epoxide hydrolase is a susceptibility factor for heart failure in a rat model of human disease
10.1038/ng.129Nature Genetics405529-53
Policy advocacy in hard times: the impact of economic performance on gendering executive attention
Securing executive attention for new policy demands is notoriously difficult as governmental agendas are crowded by established or ‘core’ policy issues. This article investigates whether it is harder for new and costly policy issues to reach the government agenda when the economy is performing badly. It examines whether, and the extent to which, costly gender equality issues regarding women’s access to the labour market, equal treatment at work and care activities, are more likely to achieve executive attention when the economy is performing well. Using the Comparative Policy Agendas database, a systematic, quantitative analysis is conducted of when and why policies promoting sex equality in the division of labour reach executive agendas. The findings confirm that advocacy for costly gender equality measures is easier to make in times of economic growth. It is also found that female representation in parliament strengthens advocacy for executive attention and reduces friction on policy agenda change