3,180 research outputs found
The variability behavior of CoRoT M-giant Stars
For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space
mission has acquired photometric data from more than one hundred thousand point
sources towards and directly opposite from the inner and outer regions of the
Galaxy. The high temporal resolution of the CoRoT data combined with the wide
time span of the observations has enabled the study of short and long time
variations in unprecedented detail. From the initial sample of 2534 stars
classified as M-giants in the CoRoT databasis, we selected 1428 targets that
exhibit well defined variability, using visual inspection. The variability
period and amplitude of C1 stars (stars having Teff < 4200 K) were computed
using Lomb-Scargle and harmonic fit methods. The trends found in the V-I vs J-K
color-color diagram are in agreement with standard empirical calibrations for
M-giants. The sources located towards the inner regions of the Galaxy are
distributed throughout the diagram while the majority of the stars towards the
outer regions of the Galaxy are spread between the calibrations of M-giants and
the predicted position for Carbon stars. The stars classified as supergiants
follow a different sequence from the one found for giant stars. We also
performed a KS test of the period and amplitude of stars towards the inner and
outer regions of the Galaxy. We obtained a low probability that the two samples
come from the same parent distribution. The observed behavior of the
period-amplitude and period-Teff diagrams are, in general, in agreement with
those found for Kepler sources and ground based photometry, with pulsation
being the dominant cause responsible for the observed modulation. We also
conclude that short-time variations on M-Giant stars do not exist orare very
rare and the few cases we found are possibly related to biases or background
stars.Comment: 11 pages, 6 figure
The air-breathing cycle of Hoplosternum littorale (Hancock, 1828)(Siluriformes: Callichthyidae)
Resistência a inseticidas em populações de Tibraca limbativentris.
O objetivo desse trabalho foi determinar a curva de dose-resposta para verificar a suscetibilidade do percevejo do colmo Tibraca limbativentris provenientes dos estados de Goiás e Pará aos inseticidas lambda-cialotrina e endosulfan
Curva de dose-resposta a inseticidas para o percevejo dos grãos Oebalus poecilus (Hemiptera: Pentatomidae).
Esse trabalho objetivou determinar a curva de dose resposta para a população padrão de suscetibilidade de O. poecilus aos inseticidas endosulfan e lambda-cialotrina, para posterior estudo de detecção em outras populações desta espécie nas principais regiões produtoras de arroz
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