37 research outputs found
The Abell Cluster A586 and the Detection of the Equivalence Principle
We discuss the current bounds on the Equivalence Principle, in particular
from structure formation and, reexamine in this context, the recent claim on
the evidence of the interaction between dark matter and dark energy in the
Abell Cluster A586 and the ensued violation of the Equivalence Principle.Comment: 9 pages, 2 Figures. GRG forma
Stimulated Neutrino Conversion in the CERN Beam
We discuss the possibility of searching for anomalous magnetic transitions of
neutrinos in the CERN beam induced by the absorption or emission of low-energy
photons in a high-quality resonant cavity such as the LEP radio-frequency
cavities. With the attainable sensitivities of the present CERN neutrino
detectors, this experiment would impose strong limits on this transition and on
the radiative decay lifetime of neutrinos with masses in the range of interest
to the resolution of the dark matter solar and atmospheric neutrino puzzles.Comment: Latex file, 9 pages, 2 postscript figure
SOBRINA Spanish study-analysing the frequency, cost and adverse events associated with overuse in primary care: protocol for a retrospective cohort study
Introduction Several institutions and quality national agencies have fostered the creation of recommendations on what not to do to reduce overuse in clinical practice. In primary care, their impact has hardly been studied. The frequency of adverse events (AEs) associated with doing what must not be done has not been analysed, either. The aim of this study is to measure the frequency of overuse and AEs associated with doing what must not be done (commission errors) in primary care and their cost. Methods and analysis A coordinated, multicentric, national project. A retrospective cohort study using computerised databases of primary care medical records from national agencies and regional health services will be conducted to analyse the frequency of the overuse due to ignore the do-not-do recommendations, and immediately afterwards, depending on their frequency, a representative random sample of medical records will be reviewed with algorithms (triggers) that determine the frequency of AEs associated with these recommendations. Cost will determine by summation of the direct costs due to the consultation, pharmacy, laboratory and imaging activities according to the cases. Ethics and dissemination The study protocol has been approved by the Ethics Committee of Primary Care Research of the Valencian Community. We aim to disseminate the findings through international peerreviewed journals and on the website (http://www. nohacer. es/). Outcomes will be used to incorporate algorithms into the electronic history to assist in making clinical decisions
Observational constraint on generalized Chaplygin gas model
We investigate observational constraints on the generalized Chaplygin gas
(GCG) model as the unification of dark matter and dark energy from the latest
observational data: the Union SNe Ia data, the observational Hubble data, the
SDSS baryon acoustic peak and the five-year WMAP shift parameter. It is
obtained that the best fit values of the GCG model parameters with their
confidence level are ()
, ()
. Furthermore in this model, we can see that the
evolution of equation of state (EOS) for dark energy is similar to quiessence,
and its current best-fit value is with the confidence
level .Comment: 9 pages, 5 figure
Search for heavy neutrinos mixing with tau neutrinos
We report on a search for heavy neutrinos (\nus) produced in the decay
D_s\to \tau \nus at the SPS proton target followed by the decay \nudecay in
the NOMAD detector. Both decays are expected to occur if \nus is a component
of .\
From the analysis of the data collected during the 1996-1998 runs with
protons on target, a single candidate event consistent with
background expectations was found. This allows to derive an upper limit on the
mixing strength between the heavy neutrino and the tau neutrino in the \nus
mass range from 10 to 190 . Windows between the SN1987a and Big Bang
Nucleosynthesis lower limits and our result are still open for future
experimental searches. The results obtained are used to constrain an
interpretation of the time anomaly observed in the KARMEN1 detector.\Comment: 20 pages, 7 figures, a few comments adde
Interacting Ricci Dark Energy with Logarithmic Correction
Motivated by the holographic principle, it has been suggested that the dark
energy density may be inversely proportional to the area of the event
horizon of the universe. However, such a model would have a causality problem.
In this work, we consider the entropy-corrected version of the holographic dark
energy model in the non-flat FRW universe and we propose to replace the future
event horizon area with the inverse of the Ricci scalar curvature. We obtain
the equation of state (EoS) parameter , the deceleration
parameter and in the presence of interaction between Dark
Energy (DE) and Dark Matter (DM). Moreover, we reconstruct the potential and
the dynamics of the tachyon, K-essence, dilaton and quintessence scalar field
models according to the evolutionary behavior of the interacting
entropy-corrected holographic dark energy model.Comment: 24 pages, accepted for publication in 'Astrophysics and Space
Science, DOI:10.1007/s10509-012-1031-8
Noether symmetry for Gauss-Bonnet dilatonic gravity
Noether symmetry for Gauss-Bonnet-Dilatonic interaction exists for a constant
dilatonic scalar potential and a linear functional dependence of the coupling
parameter on the scalar field. The symmetry with the same form of the potential
and coupling parameter exists all in the vacuum, radiation and matter dominated
era. The late time acceleration is driven by the effective cos- mological
constant rather than the Gauss-Bonnet term, while the later compensates for the
large value of the effective cosmological constant giving a plausible answer to
the well-known coincidence problem.Comment: 17 pages, 5 figures, in press on GR
First-order formalism for dark energy and dust
This work deals with first-order formalism for dark energy and dust in
standard cosmology, for models described by real scalar field in the presence
of dust in spatially flat space. The field dynamics may be standard or
tachyonic, and we show how the equations of motion can be solved by first-order
differential equations. We investigate a model to illustrate how the dustlike
matter may affect the cosmic evolution using this framework.Comment: 5 pages, 1 figure; title changed, new author included, discussions
extended, references added, version to appear in EPJ
Impact des ondulations de courant générées par un convertisseur DC-DC boost sur une pile à combustible PEM
National audienc
Impact of current ripples generated by a DC-DC boost power converter on a PEM Fuel Cell
National audienc