213 research outputs found
The self-dual gauge fields and the domain wall fermion zero modes
A new type of gauge fixing of the Coulomb gauge domain wall fermion system
that reduces the fluctuation of the effective running coupling and the
effective mass of arbitrary momentum direction including the region outside the
cylinder cut region is proposed and tested in the
gauge configurations of RBC/UKQCD collaboration.
The running coupling at the lowest momentum point does not show infrared
suppression and compatible with the experimental data extracted from the JLab
collaboration. The source of the fluctuation of the effective mass near
momentum 0.6GeV region is expected to be due to the domain wall fermion
zero modes.Comment: 12 pages 2 figures, extended arguments and references adde
Renormalization Group Analysis of \rho-Meson Properties at Finite Density
We calculate the density dependence of the -meson mass and coupling
constant() for -nucleon-nucleon vertex at one loop using the
lagrangian where the -meson is included as a dynamical gauge boson of a
hidden local symmetry. From the condition that thermodynamic potential should
not depend on the arbitrary energy scale, renormalization scale, one can
construct a renormalization group equation for the thermodynamic potential and
argue that the various renormalization group coefficients are functions of the
density or temperature. We calculate the -function for
-nucleon-nucleon coupling constant () and -function
for -meson mass (). We found that the -meson mass
and the coupling constant for drop as density increases in the
low energy limit.Comment: 24 pages, 10 figures, revised versio
Class-Discriminative Weighted Distortion Measure for VQ-based Speaker Identification
We consider the distortion measure in vector quantization based speaker identification system. The model of a speaker is a codebook generated from the set of feature vectors from the speakers voice sample. The matching is performed by evaluating the distortions between the unknown speech sample and the models in the speaker database. In this paper, we introduce a weighted distortion measure that takes into account the correlations between the known models in the database. Larger weights are assigned to vectors that have high discriminating power between the speakers and vice versa
Chiral and deconfinement transition from correlation functions: SU(2) vs. SU(3)
We study a gauge invariant order parameter for deconfinement and the chiral
condensate in SU(2) and SU(3) Yang-Mills theory in the vicinity of the
deconfinement phase transition using the Landau gauge quark and gluon
propagators. We determine the gluon propagator from lattice calculations and
the quark propagator from its Dyson-Schwinger equation, using the gluon
propagator as input. The critical temperature and a deconfinement order
parameter are extracted from the gluon propagator and from the dependency of
the quark propagator on the temporal boundary conditions. The chiral transition
is determined using the quark condensate as order parameter. We investigate
whether and how a difference in the chiral and deconfinement transition between
SU(2) and SU(3) is manifest.Comment: 15 pages, 9 figures. For clarification one paragraph and two
references added in the introduction and two sentences at the end of the
first and last paragraph of the summary. Appeared in EPJ
Introduction to the functional RG and applications to gauge theories
These lectures contain an introduction to modern renormalization group (RG)
methods as well as functional RG approaches to gauge theories. In the first
lecture, the functional renormalization group is introduced with a focus on the
flow equation for the effective average action. The second lecture is devoted
to a discussion of flow equations and symmetries in general, and flow equations
and gauge symmetries in particular. The third lecture deals with the flow
equation in the background formalism which is particularly convenient for
analytical computations of truncated flows. The fourth lecture concentrates on
the transition from microscopic to macroscopic degrees of freedom; even though
this is discussed here in the language and the context of QCD, the developed
formalism is much more general and will be useful also for other systems.Comment: 60 pages, 14 figures, Lectures held at the 2006 ECT* School
"Renormalization Group and Effective Field Theory Approaches to Many-Body
Systems", Trento, Ital
Infrared Properties of QCD from Dyson-Schwinger equations
I review recent results on the infrared properties of QCD from
Dyson-Schwinger equations. The topics include infrared exponents of
one-particle irreducible Green's functions, the fixed point behaviour of the
running coupling at zero momentum, the pattern of dynamical quark mass
generation and properties of light mesons.Comment: 47 pages, 19 figures, Topical Review to be published in J.Phys.G, v2:
typos corrected and some references adde
Detection of the pancreas-specific gene in the peripheral blood of patients with pancreatic carcinoma
The prognosis of patients with pancreatic carcinoma remains very poor. To improve the therapeutic results, the early detection of this cancer is needed. The present study was performed to detect the pancreas-specific gene, chymotrypsinogen, in the peripheral blood from patients with pancreatic carcinoma by using reverse transcription polymerase chain reaction (RT-PCR) in order to evaluate the clinical significance of this gene. Ten patients with pancreatic carcinoma, two with acute pancreatitis, three with chronic pancreatitis and ten control subjects were examined for the presence of chymotrypsinogen using RT-PCR techniques in the peripheral blood. To confirm that the chymotrypsinogen gene was expressed in a pancreas-specific manner, the expression of chymotrypsinogen in various types of human adult tissue was evaluated by RT-PCR. The specific band of the chymotrypsinogen gene was detected in the pancreas. Serial dilution studies demonstrated the chymotrypsinogen gene to be detected at a concentration of one pancreatic cell per 106 peripheral blood cells. Seven out of the ten (70%) patients with pancreatic carcinoma were found to be positive based on the RT-PCR findings. In contrast, no pancreas-specific gene was detected in the peripheral blood of any patients with acute pancreatitis, chronic pancreatitis or the control subjects. Our observations show that the detection of the pancreatic specific gene, chymotrypsinogen, is therefore useful as a genetic diagnostic marker in pancreatic carcinoma. © 1999 Cancer Research Campaig
Over-expression of lysophosphatidic acid receptor-2 in human invasive ductal carcinoma
INTRODUCTION: Lysophosphatidic acid (LPA) is a bioactive phospholipid with diverse effects on various cells. It interacts with at least three G-protein-coupled transmembrane receptors, namely LPA1, LPA2 and LPA3, whose expression in various tumours has not been fully characterized. In the present study we characterized the expression profile of LPA receptors in human breast cancer tissue and assessed the possible roles of each receptor. METHODS: The relative expression levels of each receptor's mRNA against β-actin mRNA was examined in surgically resected invasive ductal carcinomas and normal gland tissue using real-time RT-PCR. LPA2 expression was also examined immunohistochemically using a rat anti-LPA2 monoclonal antibody. RESULTS: In 25 cases normal and cancer tissue contained LPA1 mRNA at similar levels, whereas the expression level of LPA2 mRNA was significantly increased in cancer tissue as compared with its normal counterpart (3479.0 ± 426.6 versus 1287.3 ± 466.8; P < 0.05). LPA3 was weakly expressed in both cancer and normal gland tissue. In 48 (57%) out of 84 cases, enhanced expression of LPA2 protein was confirmed in carcinoma cells as compared with normal mammary epithelium by immunohistochemistry. Over-expression of LPA2 was detected in 17 (45%) out of 38 premenopausal women, as compared with 31 (67%) out of 46 postmenopausal women, and the difference was statistically significant (P < 0.05). CONCLUSION: These findings suggest that upregulation of LPA2 may play a role in carcinogenesis, particularly in postmenopausal breast cancer
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