406 research outputs found
On Common Fixed Point Theorem in Intuitionistic Fuzzy Metric Spaces with Rational Inequality
: In this paper, we use the concepts of subcompatibility and subsequential continuity in Intuitionistic Fuzzy Metric Spaces which are respectively weaker than occasionally weak compatibility and reciprocal continuity. With them, we establish a common fixed point theorem for four mapstaking rational inequality. AMS Subject Classification Codes: 47H10, 54H25 Keywords:Intuitionistic fuzzy metric space, Subcompatibility and Subsequential continuity, common fixed point theorem, implicit relation
Random Walks in Logarithmic and Power-Law Potentials, Nonuniversal Persistence, and Vortex Dynamics in the Two-Dimensional XY Model
The Langevin equation for a particle (`random walker') moving in
d-dimensional space under an attractive central force, and driven by a Gaussian
white noise, is considered for the case of a power-law force, F(r) = -
Ar^{-sigma}. The `persistence probability', P_0(t), that the particle has not
visited the origin up to time t, is calculated. For sigma > 1, the force is
asymptotically irrelevant (with respect to the noise), and the asymptotics of
P_0(t) are those of a free random walker. For sigma < 1, the noise is
(dangerously) irrelevant and the asymptotics of P_0(t) can be extracted from a
weak noise limit within a path-integral formalism. For the case sigma=1,
corresponding to a logarithmic potential, the noise is exactly marginal. In
this case, P_0(t) decays as a power-law, P_0(t) \sim t^{-theta}, with an
exponent theta that depends continuously on the ratio of the strength of the
potential to the strength of the noise. This case, with d=2, is relevant to the
annihilation dynamics of a vortex-antivortex pair in the two-dimensional XY
model. Although the noise is multiplicative in the latter case, the relevant
Langevin equation can be transformed to the standard form discussed in the
first part of the paper. The mean annihilation time for a pair initially
separated by r is given by t(r) \sim r^2 ln(r/a) where a is a microscopic
cut-off (the vortex core size). Implications for the nonequilibrium critical
dynamics of the system are discussed and compared to numerical simulation
results.Comment: 10 pages, 1 figur
Flavor Singlet Axial Vector Coupling of the Proton with Dynamical Wilson Fermions
We present the results of a full QCD lattice calculation of the flavor
singlet axial vector coupling of the proton. The simulation has been
carried out on a lattice at with dynamical
Wilson fermions. It turns out that the statistical quality of the connected
contribution to is excellent, whereas the disconnected part is
accessible but suffers from large statistical fluctuations. Using a 1st order
tadpole improved renormalization constant , we estimate .Comment: 13 pages, 5 eps figures, minor changes to text and citation
Persistence in a Stationary Time-series
We study the persistence in a class of continuous stochastic processes that
are stationary only under integer shifts of time. We show that under certain
conditions, the persistence of such a continuous process reduces to the
persistence of a corresponding discrete sequence obtained from the measurement
of the process only at integer times. We then construct a specific sequence for
which the persistence can be computed even though the sequence is
non-Markovian. We show that this may be considered as a limiting case of
persistence in the diffusion process on a hierarchical lattice.Comment: 8 pages revte
Inflammatory breast cancer: dynamic contrast-enhanced MR in patients receiving bevacizumab. Initial experience
To retrospectively compare three dynamic contrast material-enhanced
magnetic resonance (MR) imaging (dynamic MR imaging) analytic methods to
determine the parameter or combination of parameters most strongly associated
with changes in tumor microvasculature during treatment with bevacizumab alone
and bevacizumab plus chemotherapy in patients with inflammatory or locally
advanced breast cancer. MATERIALS AND METHODS: This study was conducted in
accordance with the institutional review board of the National Cancer Institute
and was compliant with the Privacy Act of 1974. Informed consent was obtained
from all patients. Patients with inflammatory or locally advanced breast cancer
were treated with one cycle of bevacizumab alone (cycle 1) followed by six cycles
of combination bevacizumab and chemotherapy (cycles 2-7). Serial dynamic MR
images were obtained, and the kinetic parameters measured by using three dynamic
analytic MR methods (heuristic, Brix, and general kinetic models) and two
region-of-interest strategies were compared by using two-sided statistical tests.
A P value of .01 was required for significance. RESULTS: In 19 patients, with use
of a whole-tumor region of interest, the authors observed a significant decrease
in the median values of three parameters measured from baseline to cycle 1:
forward transfer rate constant (Ktrans) (-34% relative change, P=.003), backflow
compartmental rate constant extravascular and extracellular to plasma (Kep) (-15%
relative change, P<.001), and integrated area under the gadolinium concentration
curve (IAUGC) at 180 seconds (-23% relative change, P=.009). A trend toward
differences in the heuristic slope of the washout curve between responders and
nonresponders to therapy was observed after cycle 1 (bevacizumab alone, P=.02).
The median relative change in slope of the wash-in curve from baseline to cycle 4
was significantly different between responders and nonresponders (P=.009).
CONCLUSION: The dynamic contrast-enhanced MR parameters Ktrans, Kep, and IAUGC at
180 seconds appear to have the strongest association with early physiologic
response to bevacizumab. Clinical trial registration no. NCT0001654
Leptonic and Semileptonic Decays of Charm and Bottom Hadrons
We review the experimental measurements and theoretical descriptions of
leptonic and semileptonic decays of particles containing a single heavy quark,
either charm or bottom. Measurements of bottom semileptonic decays are used to
determine the magnitudes of two fundamental parameters of the standard model,
the Cabibbo-Kobayashi-Maskawa matrix elements and . These
parameters are connected with the physics of quark flavor and mass, and they
have important implications for the breakdown of CP symmetry. To extract
precise values of and from measurements, however,
requires a good understanding of the decay dynamics. Measurements of both charm
and bottom decay distributions provide information on the interactions
governing these processes. The underlying weak transition in each case is
relatively simple, but the strong interactions that bind the quarks into
hadrons introduce complications. We also discuss new theoretical approaches,
especially heavy-quark effective theory and lattice QCD, which are providing
insights and predictions now being tested by experiment. An international
effort at many laboratories will rapidly advance knowledge of this physics
during the next decade.Comment: This review article will be published in Reviews of Modern Physics in
the fall, 1995. This file contains only the abstract and the table of
contents. The full 168-page document including 47 figures is available at
http://charm.physics.ucsb.edu/papers/slrevtex.p
The Geminga Fraction
Radio-quiet gamma-ray pulsars like Geminga may account for a number of the unidentified EGRET sources in the Galaxy. The number of Geminga-like pulsars is very sensitive to the geometry of both the gamma-ray and radio beams. Recent studies of the shape and polarization of pulse profiles of young radio pulsars have provided evidence that their radio emission originates in wide cone beams at altitudes that are a significant fraction (1 -10%) of their light cylinder radius. Such wide radio emission beams will be visible at a much larger range of observer angles than the narrow core components thought to originate at lower altitude. Using 3D geometrical modeling that includes relativistic effects from pulsar rotation, we study the visibility of such radio cone beams as well as that of the gamma-ray beams predicted by slot gap and outer gap models. From the results of this study one can obtain revised predictions for the fraction of Geminga-like, radio quiet pulsars present in the gamma-ray pulsar population
dependence of the quark distribution functions in the CQM
Chiral constituent quark model with configuration mixing (\chiCQM_{{\rm
config}}) is known to provide a satisfactory explanation of the ``proton spin
problem'' and related issues. In order to enlarge the scope of \chiCQM_{{\rm
config}}, we have attempted to phenomenologically incorporate x-dependence in
the quark distribution functions. In particular, apart from calculating valence
and sea quark distributions q_{{\rm val}}(x) and \bar q(x), we have carried out
a detailed analysis to estimate the sea quark asymmetries \bar d(x)-\bar u(x),
\bar d(x)/\bar u(x) and \frac{\bar d(x)-\bar u(x)}{u(x)-d(x)} as well as spin
independent structure functions F_2^p(x)-F_2^n(x) and as
functions of . We are able to achieve a satisfactory fit for all the above
mentioned quantities simultaneously. The inclusion of effects due to
configuration mixing have also been examined in the case F_2^p(x)-F_2^n(x) and
F_2^n(x)/F_2^p(x) where the valence quark distributions dominate and it is
found that it leads to considerable improvement in the results. Further, the
valence quark structure has also be tested by extrapolating the predictions of
our model in the limit x \to 1 where data is not available.Comment: 20 pages, 7 figures. To appear in Eur. Phys. J.
Proximity effect at superconducting Sn-Bi2Se3 interface
We have investigated the conductance spectra of Sn-Bi2Se3 interface junctions
down to 250 mK and in different magnetic fields. A number of conductance
anomalies were observed below the superconducting transition temperature of Sn,
including a small gap different from that of Sn, and a zero-bias conductance
peak growing up at lower temperatures. We discussed the possible origins of the
smaller gap and the zero-bias conductance peak. These phenomena support that a
proximity-effect-induced chiral superconducting phase is formed at the
interface between the superconducting Sn and the strong spin-orbit coupling
material Bi2Se3.Comment: 7 pages, 8 figure
Centrality Dependence of the High p_T Charged Hadron Suppression in Au+Au collisions at sqrt(s_NN) = 130 GeV
PHENIX has measured the centrality dependence of charged hadron p_T spectra
from central Au+Au collisions at sqrt(s_NN)=130 GeV. The truncated mean p_T
decreases with centrality for p_T > 2 GeV/c, indicating an apparent reduction
of the contribution from hard scattering to high p_T hadron production. For
central collisions the yield at high p_T is shown to be suppressed compared to
binary nucleon-nucleon collision scaling of p+p data. This suppression is
monotonically increasing with centrality, but most of the change occurs below
30% centrality, i.e. for collisions with less than about 140 participating
nucleons. The observed p_T and centrality dependence is consistent with the
particle production predicted by models including hard scattering and
subsequent energy loss of the scattered partons in the dense matter created in
the collisions.Comment: 7 pages text, LaTeX, 6 figures, 2 tables, 307 authors, resubmitted to
Phys. Lett. B. Revised to address referee concerns. Plain text data tables
for the points plotted in figures for this and previous PHENIX publications
are publicly available at
http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
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