8,759 research outputs found
Determining the Gamma-Ray Burst Rate as a Function of Redshift
We exploit the 14 gamma-ray bursts (GRBs) with known redshifts z and the 7
GRBs for which there are constraints on z to determine the GRB rate R_{GRB}(z),
using a method based on Bayesian inference. We find that, despite the
qualitative differences between the observed GRB rate and estimates of the SFR
in the universe, current data are consistent with R_{GRB}(z) being proportional
to the SFR.Comment: To appear in Procs. of Gamma-Ray Bursts in the Afterglow Era: 2nd
Workshop, 3 pages, 3 figures, LaTe
Determining the GRB (Redshift, Luminosity)-Distribution Using Burst Variability
We use the possible Cepheid-like luminosity estimator for the long-duration gamma-ray bursts (GRBs) developed by Reichart et al. (2000) to estimate the intrinsic luminosity, and thus the redshift, of 907 long-duration GRBs from the BATSE 4B catalog. We describe a method based on Bayesian inference which allows us to infer the intrinsic GRB burst rate as a function of redshift for bursts with estimated intrinsic luminosities and redshifts. We apply this method to the above sample of long-duration GRBs, and present some preliminary results
An inhibitory effect of D-Mannoheptulose on lactate formation in human whole blood in vitro
Numeración errónea en el original
Caracterización de la Calidad del Agua en Áreas Potenciales para Acuicultura en la Costa Sur del Golfo de Cariaco, Estado Sucre, Venezuela
Early Maladaptive Schemas among children: a new way to screen for depressed child
How can children’s schemas evolve into adult schemas that are responsible for depression? To answer
this question, we translated Schmidt, Joiner, Young, and Telch’s (1995) Early Maladaptive Schema
Questionnaire into French and adapted it to children. We administered the questionnaire to two groups
of children in years seven to ten (N = 252), one group containing children suffering from depression
and the other containing children with no psychiatric disorders. The results provided insight into the
structure of depression schemas. From a clinical perspective, we stress the possibility of using this
tool to individually or collectively detect «normal» and «abnormal» schemas in children
Early maladaptive schemas among children: a new way to screen for depressed child
STOCHASTIC DYNAMICS OF LARGE-SCALE INFLATION IN DE~SITTER SPACE
In this paper we derive exact quantum Langevin equations for stochastic
dynamics of large-scale inflation in de~Sitter space. These quantum Langevin
equations are the equivalent of the Wigner equation and are described by a
system of stochastic differential equations. We present a formula for the
calculation of the expectation value of a quantum operator whose Weyl symbol is
a function of the large-scale inflation scalar field and its time derivative.
The unique solution is obtained for the Cauchy problem for the Wigner equation
for large-scale inflation. The stationary solution for the Wigner equation is
found for an arbitrary potential. It is shown that the large-scale inflation
scalar field in de Sitter space behaves as a quantum one-dimensional
dissipative system, which supports the earlier results. But the analogy with a
one-dimensional model of the quantum linearly damped anharmonic oscillator is
not complete: the difference arises from the new time dependent commutation
relation for the large-scale field and its time derivative. It is found that,
for the large-scale inflation scalar field the large time asymptotics is equal
to the `classical limit'. For the large time limit the quantum Langevin
equations are just the classical stochastic Langevin equations (only the
stationary state is defined by the quantum field theory).Comment: 21 pages RevTex preprint styl
Flavour-Independent Searches for Neutral Higgs Bosons decaying into hadrons with the DELPHI Detector at LEP2
Measurement of the time resolution of the installed muon chambers with the 2008 cosmic runs
One of the main goals of the LHCb muon system commissioning is to access the detector performance and identify possible misbehaviors in the installed chambers: this is partially possible using cosmic ray muons tracked through the detector. In this note we focus on the measurement of the time resolution of the whole installed detector (M2-M5 stations) using the 2008 commissioning data. Results are compared with the expected performances
Carcinoma cells activate AMP-activated protein kinase-dependent autophagy as survival response to kaempferol-mediated energetic impairment.
Kaempferol, a dietary cancer chemopreventive polyphenol, has been reported to trigger apoptosis in several tumor histotypes, but the mechanism underlying this phenomenon is not fully understood. Here, we demonstrate that in HeLa cells, kaempferol induces energetic failure due to inhibition of both glucose uptake and Complex I of the mitochondrial respiratory chain. As adaptive response, cells activate autophagy, the occurrence of which was established cytofluorometrically, upon acridine orange staining, and immunochemically, by following the increase of the autolysosome-associated form of the microtubule-associated protein light chain 3 (LC3-II). Autophagy is an early and reversible process occurring as survival mechanisms against apoptosis. Indeed, chemical inhibition of autophagy, by incubations with monensin, wortmannin, 3-methyladenine, or by silencing Atg5, significantly increases the extent of apoptosis, which takes place via the mitochondrial pathway, and shortens the time in which the apoptotic markers are detectable. We also demonstrate that autophagy depends on the early activation of the AMP-activated protein kinase (AMPK)/mTOR-mediated pathway. The overexpression of dominant negative AMPK results in a decrease of autophagic cells, a decrement of LC3-II levels, and a significant increase of apoptosis. Experiments performed with another carcinoma cell line yielded the same results, suggesting for kaempferol a unique mechanism of action
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