12,545 research outputs found
Radiative corrections to all charge assignments of heavy quark baryon semileptonic decays
In semileptonic decays of spin-1/2 baryons containing heavy quarks up to six
charge assignments for the baryons and lepton are possible. We show that the
radiative corrections to four of these possibilities can be directly obtained
from the final results of the two possibilities previously studied. There is no
need to recalculate integrals over virtual or real photon momentum or any
traces.Comment: 15 pages, 2 figures, RevTex. Extended discussion. Final version to
appear in Physical Review
On the Moyal deformation of Nahm Equations in seven dimensions
We show how the reduced (anti-)self-dual Yang-Mills equations in seven
dimensions described by the Nahm equations can be carried over to the
Weyl-Wigner-Moyal formalism. In the process some new solutions for the cases of
gauge groups SU(2) and SL(2,R) are explicitly obtained.Comment: 16+1 pages, LaTeX, no figure
From Perturbation Theory to Confinement: How the String Tension is built up
We study the spatial volume dependence of electric flux energies for SU(2)
Yang-Mills fields on the torus with twisted boundary conditions. The results
approach smoothly the rotational invariant Confinement regime. The would-be
string tension is very close to the infinite volume result already for volumes
of . We speculate on the consequences of our result for
the Confinement mechanism.Comment: 6p, ps-file (uuencoded). Contribution to Lattice'93 Conference
(Dallas, 1993). Preprint INLO-PUB 18/93, FTUAM-93/4
Hypoxic Cell Waves around Necrotic Cores in Glioblastoma: A Biomathematical Model and its Therapeutic Implications
Glioblastoma is a rapidly evolving high-grade astrocytoma that is
distinguished pathologically from lower grade gliomas by the presence of
necrosis and microvascular hiperplasia. Necrotic areas are typically surrounded
by hypercellular regions known as "pseudopalisades" originated by local tumor
vessel occlusions that induce collective cellular migration events. This leads
to the formation of waves of tumor cells actively migrating away from central
hypoxia. We present a mathematical model that incorporates the interplay among
two tumor cell phenotypes, a necrotic core and the oxygen distribution. Our
simulations reveal the formation of a traveling wave of tumor cells that
reproduces the observed histologic patterns of pseudopalisades. Additional
simulations of the model equations show that preventing the collapse of tumor
microvessels leads to slower glioma invasion, a fact that might be exploited
for therapeutic purposes.Comment: 29 pages, 9 figure
Numerical precision radiative corrections to the Dalitz plot of baryon semileptonic decays including the spin-momentum correlation of the decaying and emitted baryons
We calculate the radiative corrections to the angular correlation between the
polarization of the decaying and the direction of the emitted spin one-half
baryons in the semileptonic decay mode. The final results are presented, first,
with the triple integration of the bremsstrahlung photon ready to be performed
numerically and, second, in an analytical form. A third presentation of our
results in the form of numerical arrays of coefficients to be multiplied by the
quadratic products of form factors is discussed. This latter may be the most
practical one to use in Monte Carlo simulations. A series of crosschecks is
performed. Previous results to order (alpha/pi)(q/M_1) for the decays of
unpolarized baryons are reviewed, too, where q is the momentum transfer and M_1
is the mass of the decaying baryon. This paper is self-contained and organized
to make it accessible and reliable in the analysis of the Dalitz plot of
precision experiments involving heavy quarks and is not compromised to fixing
the form factors at predetermined values. It is assumed that the real photons
are kinematically discriminated. Otherwise, our results have a general
model-independent applicability.Comment: 34 pages, 4 tables, no figures. Some sections have been shortened.
Conclusions remain unchange
Generalized granuloma annulare after pneumococcal vaccination
Granuloma annulare may be caused by multiple triggers. Among these are vaccinations, which have been described as an infrequent cause of granuloma annulare. The authors report the first case of generalized granuloma annulare associated with pneumococcal vaccination in a 57-year-old woman, who presented cutaneous lesions 12 days after vaccination
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