132 research outputs found
On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
The Fermi-LAT experiment recently reported high precision measurements of the
spectrum of cosmic-ray electrons-plus-positrons (CRE) between 20 GeV and 1 TeV.
The spectrum shows no prominent spectral features, and is significantly harder
than that inferred from several previous experiments. Here we discuss several
interpretations of the Fermi results based either on a single large scale
Galactic CRE component or by invoking additional electron-positron primary
sources, e.g. nearby pulsars or particle Dark Matter annihilation. We show that
while the reported Fermi-LAT data alone can be interpreted in terms of a single
component scenario, when combined with other complementary experimental
results, specifically the CRE spectrum measured by H.E.S.S. and especially the
positron fraction reported by PAMELA between 1 and 100 GeV, that class of
models fails to provide a consistent interpretation. Rather, we find that
several combinations of parameters, involving both the pulsar and dark matter
scenarios, allow a consistent description of those results. We also briefly
discuss the possibility of discriminating between the pulsar and dark matter
interpretations by looking for a possible anisotropy in the CRE flux.Comment: 29 pages, 12 figures. Final version accepted for publication in
Astroparticle Physic
Impacto del teletrabajo en el nivel de compromiso laboral (engagement) y de agotamiento de los docentes del Tecnológico Nacional de México en la pandemia COVID 19 y el retorno a la nueva normalidad.
This article have the purpose to determinate the impact that was had on the teachers of the National Technological Institute of Mexico in terms of the level of their commitment and exhaustion work during the times of COVID-19 pandemic, performing their teaching function throught teleworking, to carry out this study to work was carried out in collaboration with CIRCULAR HR Fundación Chile y UNESCO WHEC (World Higher Education Conference 2022), 1994 surveys were applied to teachers of all the categories of the Technological System. This instrument was applied in different universities convened by UNESCO, in total were 3351 surveys and the Technological System help the 59.5% of the information for this study. As part of the results obtained, it was found that if there were differences on the level of exhaustion depending on the main function of each teaching category and the gender, but the level of commitment remained the same regardless of seniority, gender or category in which teacher was.El presente artículo tiene como finalidad determinar cuál fue el impacto que se tuvo en los docentes del Tecnológico Nacional de México en cuanto a su nivel de compromiso y el agotamiento laboral durante los tiempos de pandemia COVID-19 realizando su funciones docentes a través del teletrabajo, para llevar a cabo este estudio se trabajó en colaboración con CIRCULAR HR Fundación Chile Y UNESCO WHEC (World Higher Education Conference 2022), se aplicaron 1994 encuestas a docentes de todas las categorías del Sistema Tecnológico. Este instrumento fue aplicado a diferentes universidades convocadas por la UNESCO, en total fueron 3351 encuestas y el Sistema Tecnológico aportó el 59.5% de la información para este estudio. Como parte de los resultados obtenidos se encontró que si hay diferencias en nivel de agotamiento dependiendo de la función principal de cada categoría docente y el género, pero el nivel de compromiso se mantenía igual independientemente de la antigüedad, género o categoría en la que estuviera el docente
Galaxy Clusters Associated with Short GRBs. II. Predictions for the Rate of Short GRBs in Field and Cluster Early-Type Galaxies
We determine the relative rates of short GRBs in cluster and field early-type
galaxies as a function of the age probability distribution of their
progenitors, P(\tau) \propto \tau^n. This analysis takes advantage of the
difference in the growth of stellar mass in clusters and in the field, which
arises from the combined effects of the galaxy stellar mass function, the
early-type fraction, and the dependence of star formation history on mass and
environment. This approach complements the use of the early- to late-type host
galaxy ratio, with the added benefit that the star formation histories of
early-type galaxies are simpler than those of late-type galaxies, and any
systematic differences between progenitors in early- and late-type galaxies are
removed. We find that the ratio varies from R(cluster)/R(field) ~ 0.5 for n =
-2 to ~ 3 for n = 2. Current observations indicate a ratio of about 2,
corresponding to n ~ 0 - 1. This is similar to the value inferred from the
ratio of short GRBs in early- and late-type hosts, but it differs from the
value of n ~ -1 for NS binaries in the Milky Way. We stress that this general
approach can be easily modified with improved knowledge of the effects of
environment and mass on the build-up of stellar mass, as well as the effect of
globular clusters on the short GRB rate. It can also be used to assess the age
distribution of Type Ia supernova progenitors.Comment: ApJ accepted versio
Experimental study of C 13 (α,n) O 16 reactions in the Majorana Demonstrator calibration data
Neutron captures and delayed decays of reaction products are common sources of backgrounds in ultrarare event searches. In this work, we studied C13(α,n)O16 reactions induced by α particles emitted within the calibration sources of the Majorana Demonstrator. These sources are thorium-based calibration standards enclosed in carbon-rich materials. The reaction rate was estimated by using the 6129-keV γ rays emitted from the excited O16 states that are populated when the incoming α particles exceed the reaction Q value. Thanks to the excellent energy performance of the Demonstrator's germanium detectors, these characteristic photons can be clearly observed in the calibration data. Facilitated by Geant4 simulations, a comparison between the observed 6129-keV photon rates and predictions by a talys-based software was performed. The measurements and predictions were found to be consistent, albeit with large statistical uncertainties. This agreement provides support for background projections from (α,n) reactions in future double-beta decay search efforts
MIBiG 3.0: a community-driven effort to annotate experimentally validated biosynthetic gene clusters
Microbial Biotechnolog
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