328 research outputs found
A basis of cranking operators for the pairing-plus-quadrupole model
We investigate the RPA normal-mode coordinates in the pairing-plus-quadrupole
model, with an eye on simplifying the application of large amplitude collective
motion techniques. At the Hartree-Bogoliubov minimum, the RPA modes are exactly
the cranking operators of the collective coordinate approach. We examine the
possibility of representing the self-consistent cranking operator by linear
combinations of a limited number of one-body operators. We study the Sm nuclei
as an example, and find that such representations exist in terms of operators
that are state-dependent in a characteristic manner.Comment: 6 pages, 1 figure, using IOP journal style files, to be published in
J. Phys.
Sterile Neutrinos and Pulsar Velocities Revisited,
We calculate the momentum given to a proto neutron star during the first 10
seconds after temperature equilibrium is reached, using recent evidence of
sterile neutrinos and a measurement of the mixing angle. This is a continuation
of an earlier estimate with a wide range of possible mixing angles. Using the
new mixing angle we find that sterile neutrinos can account for the observed
pulsar velocities.Comment: 3 pages, 2 figure
The electromagnetic effects in isospin symmetry breakings of q{\bar q} systems
The isospin symmetry breakings of q{\bar q} are investigated in the QCD sum
rule method. The electromagnetic effects are evaluated following the procedure
requiring that the electromagnetic effects for charged meson be gauge
invariant. We find that the electromagnetic effects are also dominant in the
isospin violations of rho meson, which have been shown to be the case in the
mass splittings of pions. The numerical results for the difference of pion
decay constants and the masses of rho mesons are presented, which are
consistent with the data.Comment: To appear in Phys. Rev. D (1997
Glueball enhancements in p(gamma,VV)p through vector meson dominance
Double vector meson photoproduction, p(gamma, G -> VV)p, mediated by a scalar
glueball G is investigated. Using vector meson dominance (VMD) and
Regge/pomeron phenomenology, a measureable glueball enhancement is predicted in
the invariant VV = rho rho and omega omega mass spectra. The scalar glueball is
assumed to be the lightest physical state on the daughter pomeron trajectory
governing diffractive vector meson photoproduction. In addition to cross
sections, calculations for hadronic and electromagnetic glueball decays, G -> V
V' (V,V'= rho, omega, phi, gamma), and gamma_v V -> G transition form factors
are presented based upon flavor universality, VMD and phenomenological
couplings from phi photoproduction analyses. The predicted glueball decay
widths are similar to an independent theoretical study. A novel signature for
glueball detection is also discussed
Quark propagator, instantons and gluon propagator
The Schwinger-Dyson formalism is used to check the consistency of instanton
model solutions for the quark propagator with recent models of confining gluon
propagators. We find that the models are not consistent. A major discrepancy is
the absence of a vector condensate in the instanton model that is present in
the solutions with nonperturbative confining gluons.Comment: Latex file, no figure
The finite-width Laplace sum rules for scalar glueball in instanton liquid model
In the framework of a semi-classical expansion for quantum chromodynamics in
the instanton liquid background, the correlation function of the
scalar glueball current is given. Besides the pure classical and quantum
contributions, the contributions arising from the interactions between the
classical instanton fields and quantum gluons are taken into account as well.
Instead of the usual zero-width approximation for the resonance, the
Brite-Wigner form for the spectral function of the finite-width resonance is
adopted. The family of the Laplace sum rules for the scalar glueball in quantum
chromodynamics with and without light quarks are studed. A consistency between
the subtracted and unsubtracted sum rules are very well justified, and the
values of the mass, decay width, and the coupling to the corresponding current
for the resonance in which the glueball fraction is dominant, are
obtained.Comment: 6 figure
The as a Hybrid
Using the QCD Sum Rule Method, we estimate the mass of the lowest strange
hybrid baryon with . We find the mass is approximately that of
the , whose nature has been a puzzle for many decades. Possible
tests of this result are discussed.Comment: fourteen pages seven figure
Light-Quark Mesons and Four-Quark Condensates at Finite Temperature
We propose an analog of the familiar gap equation for the case of four-quark
condensates at finite temperature. The condensates of interest correspond to
scalar, vector, psudoscalar, axial vector, and tensor Dirac structures. Working
with correlators at zero chemical potential without factorization, we arrive at
coupled equations for these four-quark condensates and the masses of certain
light-quark mesons. We study the temperature dependence of the four-quark
condensates and masses; in one of our models, factorization of the four-quark
condensates is shown to be increasingly violated as the temperature is
increased toward . The 2 tensor mesons a(1320)-f(1270) are
identified as especially sensitive probes of the four-quark condensates.Comment: Latex file, 6 Fig
Aurora B expression directly correlates with prostate cancer malignancy and influence prostate cell proliferation.
BACKGROUND: Chromosomal instability is one of the most common features of prostate cancer (PC), especially in advanced stages. Recent studies suggest that defects in mitotic checkpoints play a role in carcinogenesis. Lack of mitotic regulation induces aneuploidy in cancer cells acting thereafter as a driving force for malignant progression. Serine/threonine protein kinases of the Aurora genes family play an important throughout the entire cell cycle. In that Aurora B regulates chromosome segregation by ensuring the orientation of sister chromatids. As a consequence, the overexpression of Aurora B in diploid human cells NHDF induces the appearance of multinucleate cells.
METHODS: Archive samples of normal and neoplastic prostate tissue, and prostate derived cell lines were screened for the expression of Aurora B.
RESULTS: Immunohistochemical analysis showed increased nuclear expression of Aurora-B in high Gleason grade PCs respect to low and intermediate grade cases and in all cancers in respect to hyperplastic and normal glands. Furthermore, in the high Gleason grade anaplastic cancer tissues Aurora B expression was accompanied by the phosphorylation of the histone H3. In analogy to the in vivo situation, Aurora B was vigorously expressed in the androgen independent PC cell lines PC3 and DU145, while a very modest expression of the kinase was observed in the androgen sensitive LnCap cells and in the EPN cells, a line of epithelial cells derived from normal prostate tissue. In addition, in PC3 cells Aurora B expression is accompanied the by the phosphorylation of the histone H3. The block of Aurora B expression induced by an inhibitor of Aurora kinase activity significantly reduced the growth of prostate carcinoma cells, but not that of non-transformed EPN cells.
CONCLUSIONS: Our data are the first demonstration of a role of Aurora B in PC progression. In addition, the observation that Aurora B specific inhibitors interfere with PC cell proliferation but not with that of non-transformed prostate epithelial cells suggest that Aurora B is a potential therapeutic target for PC
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