1,443 research outputs found
Constraining decaying dark energy density models with the CMB temperature-redshift relation
We discuss the thermodynamic and dynamical properties of a variable dark
energy model with density scaling as , z being the
redshift. These models lead to the creation/disruption of matter and radiation,
which affect the cosmic evolution of both matter and radiation components in
the Universe. In particular, we have studied the temperature-redshift relation
of radiation, which has been constrained using a recent collection of cosmic
microwave background (CMB) temperature measurements up to . We find
that, within the uncertainties, the model is indistinguishable from a
cosmological constant which does not exchange any particles with other
components. Future observations, in particular measurements of CMB temperature
at large redshift, will allow to give firmer bounds on the effective equation
of state parameter for such types of dark energy models.Comment: 9 pages, 1 figure, to appear in the Proceedings of the 3rd
Italian-Pakistani Workshop on Relativistic Astrophysics, Lecce 20-22 June
2011, published in Journal of Physics: Conference Series (JPCS
A double-ended queue with catastrophes and repairs, and a jump-diffusion approximation
Consider a system performing a continuous-time random walk on the integers,
subject to catastrophes occurring at constant rate, and followed by
exponentially-distributed repair times. After any repair the system starts anew
from state zero. We study both the transient and steady-state probability laws
of the stochastic process that describes the state of the system. We then
derive a heavy-traffic approximation to the model that yields a jump-diffusion
process. The latter is equivalent to a Wiener process subject to randomly
occurring jumps, whose probability law is obtained. The goodness of the
approximation is finally discussed.Comment: 18 pages, 5 figures, paper accepted by "Methodology and Computing in
Applied Probability", the final publication is available at
http://www.springerlink.co
High-resolution tracking in a GEM-Emulsion detector
SHiP (Search for Hidden Particles) is a beam dump experiment proposed at the
CERN SPS aiming at the observation of long lived particles very weakly coupled
with ordinary matter mostly produced in the decay of charmed hadrons. The beam
dump facility of SHiP is also a copious factory of neutrinos of all three kinds
and therefore a dedicated neutrino detector is foreseen in the SHiP apparatus.
The neutrino detector exploits the Emulsion Cloud Chamber technique with a
modular structure, alternating walls of target units and planes of electronic
detectors providing the time stamp to the event. GEM detectors are one of the
possible choices for this task. This paper reports the results of the first
exposure to a muon beam at CERN of a new hybrid chamber, obtained by coupling a
GEM chamber and an emulsion detector. Thanks to the micrometric accuracy of the
emulsion detector, the position resolution of the GEM chamber as a function of
the particle inclination was evaluated in two configurations, with and without
the magnetic fiel
A Formal Study of the Privacy Concerns in Biometric-Based Remote Authentication Schemes
With their increasing popularity in cryptosystems, biometrics have attracted more and more attention from the information security community. However, how to handle the relevant privacy concerns remains to be troublesome. In this paper, we propose a novel security model to formalize the privacy concerns in biometric-based remote authentication schemes. Our security model covers a number of practical privacy concerns such as identity privacy and transaction anonymity, which have not been formally considered in the literature. In addition, we propose a general biometric-based remote authentication scheme and prove its security in our security model
Efficacy of rituximab-bendamustine in cold agglutinin haemolytic anaemia refractory to previous chemo-immunotherapy : a case report
Can miRNAs be useful biomarkers in improving prognostic stratification in endometrial cancer patients? An update review
Endometrial cancer (EC) is the most common gynecological cancer, with annual incidence rates in Western countries ranging between 15 and 25 per 100 000 women. About 15% to 20% of patients with EC have high-risk disease and follow an aggressive clinical course. Unfortunately, the assessment of histologic parameters is poorly reproducible and conventional clinicopathological and molecular features do not reliably predict either the patient's response to the available treatments or the definition of personalized therapeutic approaches. In this context, the identification of novel diagnostic and prognostic biomarkers, which can be integrated in the current classification schemes, represents an unmet clinical need and an important challenge. miRNAs are key players in cancer by regulating the expression of specific target genes. Their role in EC, in association with clinical and prognostic tumor biomarkers, has been investigated but, so far, with little consensus among the studies. The present review aims to describe the recent advances in miRNAs research in EC taking into consideration the current classification schemes and to highlight the most promising miRNAs. Finally, a perspective point of view sheds light on the challenges ahead in the landscape of EC
Comparative efficacy and acceptability of pharmacological treatments for insomnia in adults: A systematic review and network meta-analysis
This is the protocol for a review and there is no abstract. The objectives are as follows: 1) To compare individual pharmacological treatments for insomnia in adults in terms of: efficacy, measured as self-rated quality of sleep or satisfaction with sleep; and acceptability of treatment. 2) To generate a clinically-useful hierarchy of available pharmacological treatments for insomnia in adults, according to their efficacy and acceptability
Adipose Tissue Plasticity During Catch-Up Fat Driven by Thrifty Metabolism: Relevance for Muscle-Adipose Glucose Redistribution During Catch-Up Growth
OBJECTIVE: Catch-up growth, a risk factor for later type 2 diabetes, is characterized by hyperinsulinemia, accelerated body-fat recovery (catch-up fat), and enhanced glucose utilization in adipose tissue. Our objective was to characterize the determinants of enhanced glucose utilization in adipose tissue during catch-up fat. RESEARCH DESIGN AND METHODS: White adipose tissue morphometry, lipogenic capacity, fatty acid composition, insulin signaling, in vivo glucose homeostasis, and insulinemic response to glucose were assessed in a rat model of semistarvation-refeeding. This model is characterized by glucose redistribution from skeletal muscle to adipose tissue during catch-up fat that results solely from suppressed thermogenesis (i.e., without hyperphagia). RESULTS: Adipose tissue recovery during the dynamic phase of catch-up fat is accompanied by increased adipocyte number with smaller diameter, increased expression of genes for adipogenesis and de novo lipogenesis, increased fatty acid synthase activity, increased proportion of saturated fatty acids in triglyceride (storage) fraction but not in phospholipid (membrane) fraction, and no impairment in insulin signaling. Furthermore, it is shown that hyperinsulinemia and enhanced adipose tissue de novo lipogenesis occur concomitantly and are very early events in catch-up fat. CONCLUSIONS: These findings suggest that increased adipose tissue insulin stimulation and consequential increase in intracellular glucose flux play an important role in initiating catch-up fat. Once activated, the machinery for lipogenesis and adipogenesis contribute to sustain an increased insulin-stimulated glucose flux toward fat storage. Such adipose tissue plasticity could play an active role in the thrifty metabolism that underlies glucose redistribution from skeletal muscle to adipose tissue
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