1,152 research outputs found
Critical Behavior of J/psi across the Phase Transition from QCD sum rules
We study behavior of J/psi in hot gluonic matter using
QCD sum rules. Taking into account temperature dependences of the gluon
condensates extracted from lattice thermodynamics for the pure SU(3) system, we
find that the mass and width of J/psi exhibit rapid change across the critical
temperature.Comment: 5 pages, 3 figures. Poster contribution for Quark Matter 2008. To be
published in the proceeding
Tactile experience induces c-fos expression in rat barrel cortex
Understanding gene expression that is responsive to sensory stimulation is central to elucidate molecular mechanisms underlying neuronal plasticity. In this study we demonstrate two new methods of stimulating whiskers that provide major sensory input to rat neocortex. In the first paradigm, animals were placed on the top of a cylinder and their vibrissae were brushed by hand, In the second paradigm, animals were placed for a brief period or time into a new, wired cage resulting in vibrissae stimulation when they explored the new environment. Both approaches induced c-Fos expression in barrel cortex corresponding to the stimulated vibrissae, especially in layer IV. Layers II/III and V/VI also showed c-Fos induction, but there were no detectable changes in layer VIb. The majority of c-Fos-expressing cells are probably not inhibitory neurons, because they do not show parvalbumin staining. Both paradigms, in contrast to the previous methods, are simple to use and do not require anesthesia, restraint of animals, or elaborate experimental setups
Magnetoelectricity at room temperature in Bi0.9-xTbxLa0.1FeO3 system
Magnetoelectric compounds with the general formula, Bi0.9-xRxLa0.1FeO3 (R
=Gd, Tb, Dy, etc.), have been synthesized. These show the coexistence of
ferroelectricity and magnetism, possess high dielectric constant and exhibit
magnetoelectric coupling at room temperature. Such materials may be of great
significance in basic as well as applied research.Comment: 11 pages of text and figure
Open and hidden charm in proton-nucleus and heavy-ion collisions
We review the collectivity and the suppression pattern of charmed mesons -
produced in proton-nucleus and nucleus-nucleus collisions at SPS (158 AGeV) and
RHIC energies (21 ATeV) - in comparison to dynamical and thermal models. In
particular, we examine the charmonium `melting' and the `comover dissociation'
scenarios - implemented in a microscopic transport approach - in comparison to
the available data from the SPS and RHIC. The analysis shows that the dynamics
of c, c-bar quarks at RHIC are dominated by partonic or `pre-hadronic'
interactions in the strongly coupled plasma stage. Both the `charmonium
melting' and the hadronic `comover absorption and recreation model' are found,
however, to be compatible with the experimental observation at SPS energies;
the experimental ratio of Psi'/J/Psi versus centrality clearly favors the
`hadronic comover' scenario. We find that the collective flow of charm in the
purely hadronic Hadron-String Dynamics (HSD) transport appears compatible with
the data at SPS energies, but substantially underestimates the data at top RHIC
energies. Thus, the large elliptic flow v2 of D-mesons and the low R_AA(p_T) of
J/Psi seen experimentally have to be attributed to early interactions of
non-hadronic degrees of freedom. Simultaneously, we observe that non-hadronic
interactions are mandatory in order to describe the narrowing of the J/Psi
rapidity distribution from pp to central Au+Au collisions at the top RHIC
energy. We demonstrate additionally that the strong quenching of low-pT J/Psi's
in central Au+Au collisions indicates that a large fraction of final J/Psi
mesons is created by a coalescence mechanism close to the phase boundary.
Throughout this review we, furthermore, provide predictions for charm
observables from Au+Au collisions at FAIR energies of 25-35 AGeV.Comment: review for Int. J. Mod. Phys. E, 75 pages, 50 figure
Thermodynamic limit and semi--intensive quantities
The properties of statistical ensembles with abelian charges close to the
thermodynamic limit are discussed. The finite volume corrections to the
probability distributions and particle density moments are calculated. Results
are obtained for statistical ensembles with both exact and average charge
conservation. A new class of variables (semi--intensive variables) which differ
in the thermodynamic limit depending on how charge conservation is implemented
in the system is introduced. The thermodynamic limit behavior of these
variables is calculated through the next to leading order finite volume
corrections to the corresponding probability density distributions.Comment: 11 pages, 2 figures In v2 figures are added and corresponding
editorial changes are done. Paper will be published in Journal of Physics
Anharmonicity of BaTiO_3 single crystals
By analyzing the dielectric non-linearity with the Landau thermodynamic
expansion, we find a simple and direct way to assess the importance of the
eighth order term. Following this approach, it is demonstrated that the eighth
order term is essential for the adequate description of the para/ferroelectric
phase transition of BaTiO_3. The temperature dependence of the quartic
coefficient \beta is accordingly reconsidered and is strongly evidenced by the
change of its sign above 165 C. All these findings attest to the strong
polarization anharmonicity of this material, which is unexpected for classical
displacive ferroelectrics.Comment: 4 figures, to be published in Phys. Rev.
A normal genetic variation modulates synaptic MMP-9 protein levels and the severity of schizophrenia symptoms
Abstract Matrix metalloproteinase 9 (MMPâ9) has recently emerged as a molecule that contributes to pathological synaptic plasticity in schizophrenia, but explanation of the underlying mechanisms has been missing. In the present study, we performed a phenotypeâbased genetic association study (PGAS) in > 1,000 schizophrenia patients from the Göttingen Research Association for Schizophrenia (GRAS) data collection and found an association between the MMPâ9 rs20544 C/T singleânucleotide polymorphism (SNP) located in the 3âČuntranslated region (UTR) and the severity of a chronic delusional syndrome. In cultured neurons, the rs20544 SNP influenced synaptic MMPâ9 activity and the morphology of dendritic spines. We demonstrated that Fragile X mental retardation protein (FMRP) bound the MMPâ9 3âČUTR. We also found dramatic changes in RNA structure folding and alterations in the affinity of FMRP for MMPâ9 RNA, depending on the SNP variant. Finally, we observed greater sensitivity to psychosisârelated locomotor hyperactivity in Mmpâ9 heterozygous mice. We propose a novel mechanism that involves MMPâ9âdependent changes in dendritic spine morphology and the pathophysiology of schizophrenia, providing the first mechanistic insights into the way in which the single base change in the MMPâ9 gene (rs20544) influences gene function and results in phenotypic changes observed in schizophrenia patients
Chemiluminescence of the Reaction System Ce(IV) - Non-Steroidal Anti-Inflammatory Drugs Containing Europium(III) Ions and its Application to the Determination of Naproxen in Pharmaceutical Preparations and Urine
The chemiluminescence (CL) of oxidation of non-steroidal anti-inflammatory drugs (NSAIDs) by Ce(IV) ions, was recorded in the presence and absence europium(III) ions, in solution of pHâ~â4 of solution. Kinetic curves and CL emission spectra of the all studied systems were discussed. CL of measurable intensity was observed in the Ce(IV)âNPâEu(III) reaction system only in acidic solutions. The CL spectrum rcegistered for this system shows emission bands, typical of Eu(III) ions, with maximum at λâ~â600 nm. The chemiluminescent method, based on Eu(III) emission in reaction system of NP-Ce(IV)âEu(III) in acid solution was therefore used for the determination of naproxen in mixture of non-steroidal anti-inflammatory drugs
Variation of jet quenching from RHIC to LHC and thermal suppression of QCD coupling constant
We perform a joint jet tomographic analysis of the data on the nuclear
modification factor from PHENIX at RHIC and ALICE at LHC. The
computations are performed accounting for radiative and collisional parton
energy loss with running coupling constant. Our results show that the observed
slow variation of from RHIC to LHC indicates that the QCD coupling
constant is suppressed in the quark-gluon plasma produced at LHC.Comment: 9 pages, 2 figure
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