17,276 research outputs found
Distribution of \u3ci\u3eStrongylium Crenatum\u3c/i\u3e (Coleoptera: Tenebrionidae) in the United States and First Record From Iowa
Strongylium crenatum Mäklin (Coleoptera: Tenebrionidae) is reported from Iowa for the first time. After discovering that Iowa represented a large range extension for this species, label data were collected to update its range. Numerous insect collections and references were checked and specimens representing 17 states were located
On the Eccentricity Distribution of Exoplanets from Radial Velocity Surveys
We investigate the estimation of orbital parameters by least-
Keplerian fits to radial velocity (RV) data using synthetic data sets. We find
that while the fitted period is fairly accurate, the best-fit eccentricity and
are systematically biased upward from the true values for low
signal-to-noise ratio and moderate number of observations
, leading to a suppression of the number of nearly
circular orbits. Assuming intrinsic distributions of orbital parameters, we
generate a large number of mock RV data sets and study the selection effect on
the eccentricity distribution. We find the overall detection efficiency only
mildly decreases with eccentricity. This is because although high eccentricity
orbits are more difficult to sample, they also have larger RV amplitudes for
fixed planet mass and orbital semi-major axis. Thus the primary source of
uncertainties in the eccentricity distribution comes from biases in Keplerian
fits to detections with low-amplitude and/or small , rather than
from selection effects. Our results suggest that the abundance of
low-eccentricity exoplanets may be underestimated in the current sample and we
urge caution in interpreting the eccentricity distributions of low-amplitude
detections in future RV samples.Comment: Accepted for publication in Ap
Crystals of an Insoluble Carbonate of Copper Grown under a Soda Solution
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201
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