131 research outputs found
Parasitosis en el proventrículo por Procyrnea sp. (Spiruroidea: Habronematidae), de un aguililla caminera (Rupornis magnirostris) del estado de Veracruz, México: reporte de un caso
The report presented herein describes the necropsy findings (red nodules over the linning of the proventriculus) in an adult female roadside hawk (Rupornis magnirostris) found in Veracruz State, Mexico. We further provide the description of a nematode from the genus Procyrnea found in the proventriculus wall including histopathological sections of tissue damage associated with the parasite.The report presented herein describes the necropsy findings (red nodules over the linning of the proventriculus) in an adult female roadside hawk (Rupornis magnirostris) found in Veracruz State, Mexico. We further provide the description of a nematode from the genus Procyrnea found in the proventriculus wall including histopathological sections of tissue damage associated with the parasite
Nuevas arquitecturas hardware de procesamiento de alto rendimiento para aprendizaje profundo
El diseño y fabricación de hardware es costoso, tanto en tiempo como en inversión económica, razón por la que los circuitos integrados se fabrican siempre en gran volumen, para aprovechar la economía de escala. Por esa razón la mayoría de procesadores fabricados son de propósito general, ampliando así su campo de aplicaciones. En los últimos años, sin embargo, cada vez se fabrican más procesadores para aplicaciones específicas, entre ellos aquellos destinados a acelerar el trabajo con redes neuronales profundas. Este artículo introduce la necesidad de este tipo de hardware especializado, describiendo su finalidad, funcionamiento e implementaciones actuales.The design and manufacture of hardware is expensive, both in time and in economic investment, which is why integrated circuits are always manufactured in large volume, to take advantage of economies of scale. For this reason, the majority of processors manufactured are general purpose, thus expanding its range of applications. In recent years, however, more and more processors are being manufactured for specific applications, including those aimed at accelerating work with deep neural networks. This article introduces the need for this type of specialized hardware, describing its purpose, operation and current implementations.Universidad de Granada: Departamento de Arquitectura y Tecnología de Computadore
Stellar spectral-type (mass) dependence of the dearth of close-in planets around fast-rotating stars. Architecture of Kepler confirmed single-exoplanet systems compared to star-planet evolution models
In 2013 a dearth of close-in planets around fast-rotating host stars was
found using statistical tests on Kepler data. The addition of more Kepler and
Transiting Exoplanet Survey Satellite (TESS) systems in 2022 filled this region
of the diagram of stellar rotation period (Prot) versus the planet orbital
period (Porb). We revisited the Prot extraction of Kepler planet-host stars, we
classify the stars by their spectral type, and we studied their Prot-Porb
relations. We only used confirmed exoplanet systems to minimize biases. In
order to learn about the physical processes at work, we used the star-planet
evolution code ESPEM (French acronym for Evolution of Planetary Systems and
Magnetism) to compute a realistic population synthesis of exoplanet systems and
compared them with observations. Because ESPEM works with a single planet
orbiting around a single main-sequence star, we limit our study to this
population of Kepler observed systems filtering out binaries, evolved stars,
and multi-planets. We find in both, observations and simulations, the existence
of a dearth in close-in planets orbiting around fast-rotating stars, with a
dependence on the stellar spectral type (F, G, and K), which is a proxy of the
mass in our sample of stars. There is a change in the edge of the dearth as a
function of the spectral type (and mass). It moves towards shorter Prot as
temperature (and mass) increases, making the dearth look smaller. Realistic
formation hypotheses included in the model and the proper treatment of tidal
and magnetic migration are enough to qualitatively explain the dearth of hot
planets around fast-rotating stars and the uncovered trend with spectral type.Comment: Accepted in A&A. 13 pages, 8 figure
ASASSN-15oi: A Rapidly Evolving, Luminous Tidal Disruption Event at 216 Mpc
We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the center of 2MASX J20390918-3045201 ( Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source peaked at a bolometric luminosity of ergs s and radiated a total energy of ergs over the months of observations. The early optical/UV emission of the source can be fit by a blackbody with temperature increasing from K to K while the luminosity declines from ergs s to ergs s, requiring the photosphere to be shrinking rapidly. The optical/UV luminosity decline is broadly consistent with an exponential decline, , with days. ASASSN-15oi also exhibits roughly constant soft X-ray emission that is significantly weaker than the optical/UV emission. Spectra of the source show broad helium emission lines and strong blue continuum emission in early epochs, although these features fade rapidly and are not present months after discovery. The early spectroscopic features and color evolution of ASASSN-15oi are consistent with a TDE, but the rapid spectral evolution is unique among optically-selected TDEs
Red-giant and main-sequence solar-like oscillators in binary systems revealed by ESA Gaia Data Release 3 -- Reconstructing stellar and orbital evolution from binary-star ensemble seismology
Binary systems constitute a valuable astrophysics tool for testing our
understanding of stellar structure and evolution. Systems containing a
oscillating component are interesting as asteroseismology offers independent
parameters for the oscillating component that aid the analysis. About 150 of
such systems are known in the literature. To enlarge the sample of these
benchmark objects, we crossmatch the Two-Body-Orbit Catalogue (TBO) of Gaia
DR3, with catalogs of confirmed solar-like oscillators on the main-sequence and
red-giant phase from NASA Kepler and TESS. We obtain 954 new binary system
candidates hosting solar-like oscillators, of which 45 and 909 stars are on the
main sequence and red-giant, resp., including 2 new red giants in eclipsing
systems. 918 oscillators in potentially long-periodic systems are reported. We
increase the sample size of known solar-like oscillators in binary systems by
an order of magnitude. We present the seismic properties of the full sample and
conclude that the grand majority of the orbital elements in the TBO is
physically reasonable. 82% of all TBO binary candidates with multiple times
with APOGEE are confirmed from radial-velocity measurement. However, we suggest
that due to instrumental noise of the TESS satellite the seismically inferred
masses and radii of stars with 30Hz could be
significantly overestimated. For 146 giants the seismically inferred
evolutionary state has been determined and shows clear differences in their
distribution in the orbital parameters, which are accounted the accumulative
effect of the equilibrium tide acting in these evolved binary systems. For
other 146 systems hosting oscillating stars values for the orbital inclination
were found in the TBO. From testing the TBO on the SB9 catalogue, we obtain a
completeness factor of 1/3.Comment: under review for publication in A&A (22 pages + 4 pages of appendix,
21 figures, 33 pages of tables in the Appendix
The ASAS-SN bright supernova catalogue - III. 2016
This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team
The ASAS-SN Bright Supernova Catalog - II. 2015
This manuscript presents information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during 2015, its second full year of operations. The same information is presented for bright (), spectroscopically confirmed supernovae discovered by other sources in 2015. As with the first ASAS-SN bright supernova catalog, we also present redshifts and near-UV through IR magnitudes for all supernova host galaxies in both samples. Combined with our previous catalog, this work comprises a complete catalog of 455 supernovae from multiple professional and amateur sources, allowing for population studies that were previously impossible. This is the second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team
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