1,443 research outputs found
On the nature of some SGRs and AXPs as rotation-powered neutron stars
We investigate the possibility that some SGRs/AXPs could be canonical
rotation-powered pulsars using realistic NS structure parameters instead of
fiducial values. We show that realistic NS parameters lowers the estimated
value of the magnetic field and radiation efficiency, ,
with respect to estimates based on fiducial NS parameters. We show that nine
SGRs/AXPs can be described as canonical pulsars driven by the NS rotational
energy, for computed in the soft (2--10~keV) X-ray band. We compute the
range of NS masses for which . We discuss the observed
hard X-ray emission in three sources of the group of nine potentially
rotation-powered NSs. This additional hard X-ray component dominates over the
soft one leading to in two of them. We show that 9
SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in
the soft 2--10~keV band. Interestingly, four of them show radio emission and
six have been associated with supernova remnants (including Swift J1834.9-0846
the first SGR observed with a surrounding wind nebula). These observations give
additional support to our results of a natural explanation of these sources in
terms of ordinary pulsars. Including the hard X-ray emission observed in three
sources of the group of potential rotation-powered NSs, this number of sources
with becomes seven. It remains open to verification
1) the accuracy of the estimated distances and 2) the possible contribution of
the associated supernova remnants to the hard X-ray emission.Comment: 11 pages, 14 figures, to appear in A&
Geodesic Deviation Equation in Bianchi Cosmologies
We present the Geodesic Deviation Equation (GDE) for the
Friedmann-Robertson-Walker(FRW) universe and we compare it with the equation
for Bianchi type I model. We justify consider this cosmological model due to
the recent importance the Bianchi Models have as alternative models in
cosmology. The main property of these models, solutions of Einstein Field
Equations (EFE) is that they are homogeneous as the FRW model but they are not
isotropic. We can see this because they have a non-null Weyl tensor in the GDE.Comment: Submitted to Journal of Physics: Conference Series (JPCS), ERE200
Evaluation of a Cryptococcal antigen Lateral Flow Assay in serum and cerebrospinal fluid for rapid diagnosis of cryptococcosis in Colombia
A Lateral Flow Assay to detect cryptococcal antigen (CrAg® LFA) in serum and cerebrospinal fluid for the rapid diagnosis of cryptococcosis was evaluated. A retrospective validation was performed. Sensitivity and specificity of the CrAg® LFA was 100%. High concordance (kappa index=1.0) between Cryptococcal Antigen Latex Agglutination System (CALAS®) and CrAg® LFA was observed. CrAg® LFA showed higher analytical sensitivity for detecting low concentrations of cryptococcal antigen
Indicadores del nivel del mar durante el MIS 5 y elevación tectónica en el Estrecho de Gibraltar (Norte de Marruecos)
This study investigates the morpho-sedimentary evidence of two highstands registered and
dated during MIS 5 stage by U-series dating in the North of Morocco (Strait of Gibraltar). Bioerosive
notch and mixed siliciclastic and carbonate deposits, high energy beaches with algal bioherms, were
formed in coastal environments during MIS 5a. A sea-level altitude of +10 m asl was inferred for this
substage. The record of MIS 5e-2 substage is less complete, consisting in upper foreshore and storm
deposits located some meters above the sea-level (+13-15 m asl). A tectonic uplift rate of ~0.1 mm/yr has
been estimated for the last 130 ky. This data is consistent with models of coastal uplifts elaborated for the
Gibraltar Strait.Este trabajo analiza las evidencias morfosedimentarias de dos altas paradas del nivel marino
datadas en el MIS 5 mediante series de U en el Norte de Marruecos. Durante el MIS 5a se formaron
socaves bioerosivos (notches) y facies de playas de alta energía constituidas por depósitos mixtos
siliciclástico-carbonatados. Una altura de 10 m snm ha sido estimada para esta etapa. El registro del
MIS 5e-2 es menos completo, constituidos por depósitos de foreshore y de tormenta formados varios
metros sobre el nivel del mar (+13-15 m snm). Se ha deducido una tasa de elevación tectónica de 0.1
mm/año para los últimos 130 ka. Estos datos son consistentes con los modelos previos de levantamiento
tectónico elaborados para el Estrecho de Gibraltar.Ministerio de Ciencia, Innovación y Universidades CGL2010-15810/BT
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