523 research outputs found
Hadron Mass Predictions of the Valence Approximation to Lattice QCD
We evaluate the infinite volume, continuum limits of eight hadron mass ratios
predicted by lattice QCD with Wilson quarks in the valence (quenched)
approximation. Each predicted ratio differs from the corresponding observed
value by less than 6\%.Comment: 13 pages of Latex + 2 PostScript files attached, IBM/HET 92-
Association between Posttraumatic Stress Disorder and Inflammation: A Twin Study
The association of posttraumatic stress disorder (PTSD) with cardiovascular disease risk may be mediated by inflammation. Our objective was to examine the association between PTSD and measures of inflammation and to determine whether these associations are due to shared familial or genetic factors. We measured lifetime history of PTSD using the Structured Clinical Interview for DSM-IV in 238 male middle-aged military veteran twin pairs (476 individuals), selected from the Vietnam Era Twins Registry, who were free of cardiovascular disease at baseline. We assessed inflammation using levels of high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6), fibrinogen, white blood cells, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 (ICAM-1). Geometric mean levels and percent differences by PTSD were obtained from mixed-model linear regression analyses with adjustment for potential confounders. Within-pair analysis was conducted to adjust for shared family environment and genetics (monozygotic pairs). Overall, 12.4% of participants had a lifetime history of PTSD. Adjusted mean levels of hsCRP and ICAM-1 were significantly higher among those with vs. without PTSD [hsCRP: 1.75 vs. 1.31 mg/l (33% difference); ICAM-1: 319 vs. 293 ng/ml (9% difference)]. Adjustment for depression rendered the association of PTSD with hsCRP non-statistically significant. For IL-6, no consistent association was seen. Within-pair analysis produced associations that were similar in direction for all three markers but lesser in magnitude for hsCRP and IL-6. There was no evidence of interaction by zygosity. Elevated hsCRP and ICAM-1 are associated with PTSD, and these associations may be confounded by shared non-genetic, antecedent familial and environmental factors
Revisiting glueball wave functions at zero and finite temperature
We study the sizes and thermal properties of glueballs in a three dimensional
compact Abelian gauge model on improved lattice. We predict the radii of and in the units of string tension, or and fm, for the scalar and tensor glueballs, respectively. We perform a well
controlled extrapolation of the radii to the continuum limit and observe that
our results agree with the predicted values. Using Monte Carlo simulations, we
extract the pole-mass of the lowest scalar and tensor glueballs from the
temporal correlators at finite temperature. We see a clear evidence of the
deconfined phase, and the transition appears to be similar to that of the
two-dimensional XY model as expected from universality arguments. Our results
show no significant changes in the glueball wave functions and masses in the
deconfined phase.Comment: 8 pages, 10 figure
Glueball production in radiative J/psi, Upsilon decays
Using a bound-state model of weakly bound gluons for glueballs made of two
gluons and a natural generalization of the perturbative QCD formalism for
exclusive hadronic processes, we present results for glueball production in
radiative J/psi, Upsilon decays into several possible glueball states,
including L \not= 0 ones. We perform a detailed phenomenological analysis,
presenting results for the more favored experimental candidates and for decay
angular distributions.Comment: RevTeX4, 26 pages, 11 eps figure
The finite temperature QCD phase transition with domain wall fermions
The domain wall formulation of lattice fermions is expected to support
accurate chiral symmetry, even at finite lattice spacing. Here we attempt to
use this new fermion formulation to simulate two-flavor, finite temperature QCD
near the chiral phase transition. In this initial study, a variety of quark
masses, domain wall heights and domain wall separations are explored using an
8^3 x 4 lattice. Both the expectation value of the Wilson line and the chiral
condensate show the temperature dependence expected for the QCD phase
transition. Further, the desired chiral properties are seen for the chiral
condensate, suggesting that the domain wall fermion formulation may be an
effective approach for the numerical study of QCD at finite temperature.Comment: 44 pages, 15 figure
Analysis of sex and gender-specific research reveals a common increase in publications and marked differences between disciplines
Oertelt-Prigione S, Parol R, Krohn S, PreiĂner R, Regitz-Zagrosek V. Analysis of sex and gender-specific research reveals a common increase in publications and marked differences between disciplines. BMC Medicine. 2010;8(1): 70.© 2010 Oertelt-Prigione et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Mixing of scalar glueballs and flavour-singlet scalar mesons
We discuss in detail the extraction of hadronic mixing strengths from lattice
studies. We apply this to the mixing of a scalar glueball and a scalar meson in
the quenched approximation. We also measure correlations appropriate for
flavour-singlet scalar mesons using dynamical quark configurations from UKQCD.
This enables us to compare the results from the quenched study of the mixing
with the direct determination of the mixed spectrum. Improved methods of
evaluating the disconnected quark diagrams are also presented.Comment: 23 pages, 5 postscript figure
Prognostic Value of Number and Site of Calcified Coronary Lesions Compared With the Total Score
ObjectivesThis study sought to evaluate the long-term prognostic value of the number and sites of calcified coronary lesions and to compare the accuracy of number of calcified lesions with the extent of total calcium score.BackgroundThere is a strong relationship between mortality and total coronary artery calcium (CAC) score. It is not known whether the number of calcified lesions or their location influences outcome.MethodsA total of 14,759 asymptomatic patients were referred for evaluation of CAC scanning using electron beam tomography. Univariable and multivariable Cox proportional hazards models were developed to estimate time to all-cause mortality at, on average, 6.8 years (n = 281).ResultsRisk-adjusted annual mortality was 0.19% (95% confidence interval 0.18% to 0.21%) for patients without any calcified lesions. For patients with >20 lesions, annual risk-adjusted mortality exceeded 2% per year. Mortality rates were significantly higher for left main lesions as compared to other coronary arteries with annual mortality rates of 1.3%, 2.1%, 9.2%, and 13.6% for 1 to 2, 3 to 5, and â„6 lesions, respectively (p < 0.0001). For left main CAC scores of 0 to 10, 11 to 100, 101 to 399, and 400 to 999, annual risk-adjusted mortality was 0.33%, 0.81%, 1.73%, and 7.71%, respectively (p < 0.0001). All 4 patients with a CAC score of â„1,000 in the left main died during follow-up. However, patients with more frequent calcified lesions also had higher CAC scores. Specifically, â„81% of patients with >10 calcified lesions also had a CAC score â„100. With exception, for patients with CAC scores â„1,000, annual mortality was dramatically higher at 3.0% to 4.5% for those with 1 to 5 calcified lesions as compared with 1.1% to 2.0% for those with 6 or more lesions (p < 0.0001).ConclusionsWe report that mortality rates increased proportionally with the number of calcified lesions. Although predictive information is contained in the number of calcified lesions, its added statistical value is minimal. With exception, patients with frequent lesions in the left main or those with a few large calcified lesions have a particularly high mortality risk
The Glueball Spectrum from a Potential Model
The spectrum of two-gluon glueballs below 3 GeV is investigated in a
potential model with dynamical gluon mass using variational method. The short
distance potential is approximated by one-gluon exchange, while the long
distance part is taken as a breakable string. The mass and size of the radial
as well as orbital excitations up to principle quantum number n=3 are
evaluated. The predicted mass ratios are compared with experimental and lattice
results.Comment: Revtex, 6 pages with 1 eps figur
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