910 research outputs found
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
Effect of Overdispersion of Lethal Lesions on Cell Survival Curves
We explore the effects of overdispersed DNA lesion distribution on the shapes
of cell surviving curves of mammalian cells exposed to hadrons at various
doses. To provide a theoretical framework in resolving discrepancies between
experimental data and Linear-quadratic (LQ)model predictions, we employ a
non-Poisson distribution of lethal lesions together with non-homologous
end-joining (NHEJ) pathway of double-strand break (DSB) repair. A negative
binomial (NB)distribution is used to study the effect of the overdispersion on
the shapes and possible reduction of dose-response curvature at high doses. The
error distribution is customized to include an adjustable parameter so that the
overdispersion parameter of NB is not constant but depends on the mean of the
distribution. The trends in predicted cell survival responses are compared with
the experimental data in low and high dose regions at various LET values for
proton, helium, and carbon ions. The cell survival responses calculated by the
present method reveal straightening of survival curves at high doses. This
suggests that the overdispersion causes the cell survival dose-response to
approximate log-linear behaviour at high doses. Comparison of the cell survival
predictions with the Particle Irradiation Data Ensemble (PIDE) shows that the
NB model provides better fits to the experimental data following low and
intermediate doses. Whereas the model predictions are not validated at tiny and
very high doses, nonetheless, the presented approach provides insight into
underlying microscopic mechanisms which may help to improve the radiobiological
responses along the dose-response curves and resolve discrepancies between
experimental data and current cell survival models.Comment: 11 pages, 9 figure
Contributions of point extragalactic sources to the Cosmic Microwave Background bispectrum
All the analyses of Cosmic Microwave Background (CMB) temperature maps
up--to--date show that CMB anisotropies follow a Gaussian distribution. On the
other hand, astrophysical foregrounds which hamper the detection of the CMB
angular power spectrum, are not Gaussian distributed on the sky. Therefore,
they should give a sizeable contribution to the CMB bispectrum. In fact, the
first year data of the Wilkinson Microwave Anisotropy Probe (WMAP) mission have
allowed the {\it first} detection of the extragalactic source contribution to
the CMB bispectrum at 41 GHz and, at the same time, much tighter limits than
before to non--Gaussian primordial fluctuations. In view of the above and for
achieving higher precision in current and future CMB measurements of
non--Gaussianity, in this paper we discuss a comprehensive assessment of the
bispectrum due to either uncorrelated and clustered extragalactic point sources
in the whole frequency interval around the CMB intensity peak. Our
calculations, based on current cosmological evolution models for sources, show
that the reduced angular bispectrum due to point sources, , should be
detectable in all WMAP and Planck frequency channels. We also find agreement
with the results on at 41 GHz coming from the analysis of the first
year WMAP data. Moreover, by comparing with the primordial reduced CMB
bispectrum, we find that only the peak value of the primordial bispectrum
(which appears at ) results greater than in a frequency
window around the intensity peak of the CMB. The amplitude of this window
basically depends on the capability of the source detection algorithms (i.e.,
on the achievable flux detection limit, , for sources).Comment: 26 pages, 6 Figures, use AasTex5.0, ApJ, in press, Oct. 10, 2003
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Renormalization of Anisotropy and Glueball Masses on Tadpole Improved Lattice Gauge Action
The Numerical calculations for tadpole-improved U(1) lattice gauge theory in
three-dimensions on anisotropic lattices have been performed using standard
path integral Monte Carlo techniques. Using average plaquette tadpole
renormalization scheme, simulations were done with temporal lattice spacings
much smaller than the spatial ones and results were obtained for the string
tension, the renormalized anisotropy and scalar glueball masses. We find, by
comparing the `regular' and `sideways' potentials, that tadpole improvement
results in very little renormalization of the bare anisotropy and reduces the
discretization errors in the static quark potential and in the glueball masses.Comment: 6 pages, 6 figures. Accepted for publication in Eur. Phys. J.
Cross-Cultural Differences in Interpersonal and Intrapersonal Understandings of Forgiveness
Most theorizing about forgiveness conceptualize forgiveness as an intrapersonal process in which negative feelings are transformed into positive ones, with the goal of inner peace for the forgiver. Forgiveness viewed as an interpersonal process, in contrast, focuses on behaviors, such as reconciliation, that lead to the restoration of social harmony. Several studies have demonstrated that the understanding and practice of forgiveness differs across cultures. We examined the hypothesis that North Americans understand forgiveness as more of an intrapersonal phenomenon and less of an interpersonal phenomenon relative to Asians. A sample of 153 participants recruited through Facebook completed an online survey. Findings generally support the hypothesis: North Americans endorsed intrapersonal over interpersonal understandings of forgiveness, Southeast Asians endorsed interpersonal over intrapersonal understandings, and South Asians were closely split between the two definitions. The current findings suggest that collectivistic forgiveness is not a unitary construct, and that the application of theory and therapy models based on Western conceptions of forgiveness to Asian populations may be inaccurate and even harmful. Future research should examine forgiveness across collectivistic cultures. Additionally, cross-cultural research on forgiveness should use specific affective, cognitive, and behavioral terms when assessing a participant’s level of forgiveness; broad questions assessing a participant’s general forgiveness may be difficult to interpret and compare cross-culturally
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