1,523 research outputs found
Holographic Nuclear Matter in AdS/QCD
We study the physics with finite nuclear density in the framework of AdS/QCD
with holographic baryon field included. Based on a mean field type approach, we
introduce the nucleon density as a bi-fermion condensate of the lowest mode of
the baryon field and calculate the density dependence of the chiral condensate
and the nucleon mass. We observe that the chiral condensate as well as the mass
of nucleon decrease with increasing nuclear density. We also consider the mass
splitting of charged vector mesons in iso-spin asymmetric nuclear matter.Comment: 16 pages, 3 figures, two references are added, typo corrected,
section 3.3 remove
Consequences of the partial restoration of chiral symmetry in AdS/QCD
Chiral symmetry is an essential concept in understanding QCD at low energy.
We treat the chiral condensate, which measures the spontaneous breaking of
chiral symmetry, as a free parameter to investigate the effect of partially
restored chiral symmetry on the physical quantities in the frame work of an
AdS/QCD model. We observe an interesting scaling behavior among the nucleon
mass, pion decay constant and chiral condensate. We propose a phenomenological
way to introduce the temperature dependence of a physical quantity in the
AdS/QCD model with the thermal AdS metric.Comment: 11 pages, 6 figure
Heavy quarkonium in a holographic QCD model
Encouraged by recent developments in AdS/QCD models for light quark system,
we study heavy quarkonium in the framework of the AdS/QCD models. We calculate
the masses of vector meson states using the AdS/QCD models at zero
and at finite temperature. Among the models adopted in this work, we find that
the soft wall model describes the low-lying heavy quark meson states at zero
temperature relatively well. At finite temperature, we observe that once the
bound state is above , its mass will increase with temperature until it
dissociates at a temperature of around . It is shown that the
dissociation temperature is fixed by the infrared cutoff of the models. The
present model serves as a unified non perturbative model to investigate the
properties of bound quarkonium states above .Comment: 9 pages, 1 figure, minor revision, to appear in phys. Rev.
Crystallization of the regulatory and effector domains of the key sporulation response regulator Spo0A
The key response-regulator gene of sporulation, spo0A, has been cloned from Bacillus stearothermophilus and the encoded protein purified. The DNA-binding and phospho-acceptor domains of Spo0A have been prepared by tryptic digestion of the intact protein and subsequently crystallized in forms suitable for X-ray crystallographic studies. The DNA-binding domain has been crystallized in two forms, one of which diffracts X-rays to beyond 2.5 Angstrom spacing. The crystals of the phospho-acceptor domain diffract X-rays beyond 2.0 Angstrom spacing using synchrotron radiation
A criterion for the nature of the superconducting transition in strongly interacting field theories : Holographic approach
It is beyond the present techniques based on perturbation theory to reveal
the nature of phase transitions in strongly interacting field theories.
Recently, the holographic approach has provided us with an effective dual
description, mapping strongly coupled conformal field theories to classical
gravity theories. Resorting to the holographic superconductor model, we propose
a general criterion for the nature of the superconducting phase transition
based on effective interactions between vortices. We find "tricritical" points
in terms of the chemical potential for U(1) charges and an effective
Ginzburg-Landau parameter, where vortices do not interact to separate the
second order (repulsive) from the first order (attractive) transitions. We
interpret the first order transition as the Coleman-Weinberg mechanism, arguing
that it is relevant to superconducting instabilities around quantum
criticality.Comment: 7 pages, 7 figure
Dissolved gases and radioelements in groundwaters
SIGLEAvailable from British Library Document Supply Centre- DSC:DX89941 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
A cross-cultural re-evaluation of the Exercise Addiction Inventory (EAI) in five countries
Research into the detrimental effects of excessive exercise has been conceptualized in a number of similar ways, including ‘exercise addiction’ , ‘exercise dependence’ , ‘obligatory exercising’, ‘exercise abuse’, and ‘compulsive exercise’. Among the most currently used (and psychometrically valid and reliable) instruments is the Exercise Addiction Inventory (EAI). The present study aimed to further explore the psychometric properties of the EAI by combining the datasets of a number of surveys carried out in five different countries (Denmark, Hungary, Spain, UK, and US) that have used the EAI with a total sample size of 6,031 participants. A series of multigroup confirmatory factor analyses (CFAs) were carried out examining configural invariance, metric invariance, and scalar invariance. The CFAs using the combined dataset supported the configural invariance and metric invariance but not scalar invariance. Therefore, EAI factor scores from five countries are not comparable because the use or interpretation of the scale was different in the five nations. However, the covariates of exercise addiction can be studied from a cross-cultural perspective because of the metric invariance of the scale. Gender differences among exercisers in the interpretation of the scale also emerged. The implications of the results are discussed, and it is concluded that the study’s findings will facilitate a more robust and reliable use of the EAI in future research
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