Comparison of nuclear transport models with 800A-MeV La + La data

Nuclear transport models including density- and momentum-dependent mean-field effects are compared to intranuclear-cascade models and tested on recent data on inclusive p-like cross sections for 800A-MeV La+La. We find a remarkable agreement between most model calculations but a systematic disagreement with the measured yield at 20°, possibly indicating a need for modification of nuclear transport properties at high densities

The hadron-quark phase transition in dense matter and neutron stars

We study the hadron-quark phase transition in the interior of neutron stars (NS's). We calculate the equation of state (EOS) of hadronic matter using the Brueckner-Bethe-Goldstone formalism with realistic two-body and three-body forces, as well as a relativistic mean field model. For quark matter we employ the MIT bag model constraining the bag constant by using the indications coming from the recent experimental results obtained at the CERN SPS on the formation of a quark-gluon plasma. We find necessary to introduce a density dependent bag parameter, and the corresponding consistent thermodynamical formalism. We calculate the structure of NS interiors with the EOS comprising both phases, and we find that the NS maximum masses fall in a relatively narrow interval, $1.4 M_\odot \leq M_{\rm max} \leq 1.7 M_\odot$. The precise value of the maximum mass turns out to be only weakly correlated with the value of the energy density at the assumed transition point in nearly symmetric nuclear matter.Comment: 25 pages, Revtex4, 16 figures included as postscrip

Thermal photons as a measure for the rapidity dependence of the temperature

The rapidity distribution of thermal photons produced in Pb+Pb collisions at CERN-SPS energies is calculated within scaling and three-fluid hydrodynamics. It is shown that these scenarios lead to very different rapidity spectra. A measurement of the rapidity dependence of photon radiation can give cleaner insight into the reaction dynamics than pion spectra, especially into the rapidity dependence of the temperature.Comment: 3 Figure

Restricting quark matter models by gravitational wave observation

We consider the possibilities for obtaining information about the equation of state for quark matter by using future direct observational data on gravitational waves. We study the nonradial oscillations of both fluid and spacetime modes of pure quark stars. If we observe the $f$ and the lowest $w_{\rm II}$ modes from quark stars, by using the simultaneously obtained radiation radius we can constrain the bag constant $B$ with reasonable accuracy, independently of the $s$ quark mass.Comment: To appear in Phys. Rev.

Reduction of tissue Na(+) accumulation after renal transplantation

INTRODUCTION: Chronic kidney disease (CKD) engenders salt-sensitive hypertension. Whether or not tissue Na(+) accumulation is increased in CKD patients remains uncertain. How tissue Na(+) is affected after renal transplantation has not been assessed. METHODS: We measured tissue Na(+) amount in 31 CKD patients (stage 5) and prospectively evaluated tissue Na(+) content at 3 and 6 months, following living-donor kidney transplantation. Additionally, pre- and post-transplantation data were compared to 31 age- and sex-matched control subjects. (23)Na–magnetic resonance imaging ((23)Na-MRI) was used to quantify muscle and skin Na(+) of the lower leg and water distribution was assessed by bioimpedance spectroscopy. RESULTS: Compared to control subjects, CKD patients showed increased muscle (20.7 ± 5.0 vs. 15.5 ± 1.8 arbitrary units [a.u.], P < 0.001) and skin Na+ content (21.4 ± 7.7 vs. 15.0 ± 2.3 a.u., P < 0.001), whereas plasma Na(+) concentration did not differ between groups. Restoration of kidney function by successful renal transplantation was accompanied by mobilization of tissue Na(+) from muscle (20.7 ± 5.0 vs. 16.8 ± 2.8 a.u., P < 0.001) and skin tissue (21.4 ± 7.7 vs. 16.8 ± 5.2 a.u., P < 0.001). The reduction of tissue Na(+) after transplantation was associated with improved renal function, normalization of blood pressure as well as an increase in lymphatic growth-factor concentration (vascular endothelial growth factor C [VEGF-C] 4.5 ± 1.8 vs. 6.7 ± 2.7 ng/ml, P < 0.01). CONCLUSIONS: Tissue Na+ accumulation in predialysis patients with CKD was almost completely reversed to the level of healthy controls after successful kidney transplantation

Damping rates of hard momentum particles in a cold ultrarelativistic plasma

We compute the damping rates of one-particle excitations in a cold ultrarelativistic plasma to leading order in the coupling constant e for three types of interaction: Yukawa coupling to a massless scalar boson, QED and QCD. Damping rates of charged particles in QED and QCD are of order e^3 mu, while damping rates of other particles are of order e^4 mu or e^4 mu log(1/e). We find that the damping rate of an electron or of a quark is constant far from the Fermi surface, and decreases linearly with the excitation energy close to the Fermi surface. This unusual behavior is attributed to the long-range magnetic interactions.Comment: 40 pages, Revtex, 17 Postscript figures (included). Revised versio

Factors Impacting Resiliency And Susceptibility To Social Stress

Social stress is implicated in the etiology and persistence of neuropsychiatric disorders in humans and is investigated using social defeat models in animals. Multiple factors influence how social stress impacts the brain and behavior, either reducing or enhancing susceptibility to maladaptive responses. The overarching goal of this project was to identify factors that promote resiliency to social defeat stress throughout the lifespan. In Aim 1, we investigated the effects of social defeat during development and found that a brief, pubertal social defeat increases susceptibility to adult social stress. In Aim 2, we tested whether epigenetic changes, namely histone deacetylation (HDAC), underlie either the short- or long-term effects of this brief, pubertal defeat; however, systemic HDAC inhibitors did not alter behavioral responses to pubertal social defeat. Shifting focus to potential treatment options and resiliency factors in adults, Aim 3 explored whether brain-derived neurotrophic factor (BDNF) prevents or promotes responses to social defeat stress. In Aim 3a, we determined that increasing BDNF activity either systemically or within the basolateral amygdala reduced responses to social defeat in both hamsters and mice. This is consistent with significant evidence that BDNF/tropomyosin receptor kinase B (TrkB) signaling provides anti-depressant effects but is contrary to research showing that BDNF/TrkB signaling enhances responses to chronic social defeat stress in mice. Thus, in Aim 3b, we investigated a possible explanation for these seemingly contradictory results, testing whether BDNF/TrkB activates different neural circuits after acute versus repeated social defeat. Unfortunately, these results were inconclusive. Finally, in Aim 3c, we tested the hypothesis that circadian phase underlies the contrasting BDNF/TrkB results and found that systemic TrkB agonism interacts with circadian phase to alter responses to acute social defeat in hamsters, reducing responses to social defeat during the dark phase but enhancing responses during the light phase. This interaction effect was not found in mice, wherein BDNF/TrkB signaling reduced responses to acute social defeat regardless of circadian phase. Collectively, these data demonstrate several factors that significantly impact resiliency to social stress including developmental period, stressor repetition, BDNF signaling and, lastly, circadian phase, a critical factor that is often overlooked in stress research