5,131 research outputs found
The snail-killing flies of Alaska (Diptera: Sciomyzidae)
Information is given on the geographic distribution, habitat preferences, larval foods, and immature stages for 57 species of 9 genera of Sciomyzidae known to occur in Alaska. An illustrated key to adults is included. Alaska as a habitat for sciomyzid flies is discussed, and information on feeding habits of the larvae is summarized
Discovery and Atmospheric Characterization of Giant Planet Kepler-12b: An Inflated Radius Outlier
We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 R_J is among the handful of planets with super-inflated radii above 1.65 R_J. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 M_J planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 ± 0.010 g cm^(–3). We detect the occultation of the planet at a significance of 3.7σ in the Kepler bandpass. This yields a geometric albedo of 0.14 ± 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7σ and 4σ in the 3.6 and 4.5 μm bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1σ) and e < 0.09 (3σ). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets
Spelling drills using a computer-assisted instructional system
Error repetition and student response confidence estimates during spelling drills in computers- assisted instruction progra
Spitzer Secondary Eclipses of Qatar-1b
Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks
band suggest that it may have an unusually high day side temperature,
indicative of minimal heat redistribution. There have also been indications
that the orbit may be slightly eccentric, possibly forced by another planet in
the system. We investigate the day side temperature and orbital eccentricity
using secondary eclipse observations with Spitzer. We observed the secondary
eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 micron
wavelengths. We used pixel-level decorrelation to correct for Spitzer's
intra-pixel sensitivity variations and thereby obtain accurate eclipse depths
and central phases. Our 3.6 micron eclipse depth is 0.149 +/- 0.051% and the
4.5 micron depth is 0.273 +/- 0.049%. Fitting a blackbody planet to our data
and two recent Ks band eclipse depths indicates a brightness temperature of
1506 +/- 71K. Comparison to model atmospheres for the planet indicates that its
degree of longitudinal heat redistribution is intermediate between fully
uniform and day side only. The day side temperature of the planet is unlikely
to be as high (1885K) as indicated by the ground-based eclipses in the Ks band,
unless the planet's emergent spectrum deviates strongly from model atmosphere
predictions. The average central phase for our Spitzer eclipses is 0.4984 +/-
0.0017, yielding e cos(omega) = -0.0028 +/- 0.0027. Our results are consistent
with a circular orbit, and we constrain e cos(omega) much more strongly than
has been possible with previous observations
Ground-based near-IR observations of the secondary eclipse of CoRoT-2b
We present the results of a ground-based search for the secondary eclipse of
the 3.3 Mjup transiting planet CoRoT-2b. We performed near infrared photometry
using the LIRIS instrument on the 4.2 m William Herschel Telescope, in the H
and K_s filters. We monitored the star around two expected secondary eclipses
in two nights under very good observing conditions. For the depth of the
secondary eclipse we find in H-band a 3 sigma upper limit of 0.17%, whereas we
detected a tentative eclipse with a depth of 0.16+-0.09% in the K_s-band. These
depths can be translated into brightness temperatures of T_H<2250 K and T_{K_s}
= 1890(+260-350) K, which indicate an inefficient re-distribution of the
incident stellar flux from the planet's dayside to its nightside. Our results
are in agreement with the CoRoT optical measurement (Alonso et al. 09) and with
Spitzer 4.5 and 8 micron results (Gillon et al. 09c).Comment: Astronomical Journal, accepte
The Affective Impact of Financial Skewness on Neural Activity and Choice
Few finance theories consider the influence of “skewness” (or large and asymmetric but unlikely outcomes) on financial choice. We investigated the impact of skewed gambles on subjects' neural activity, self-reported affective responses, and subsequent preferences using functional magnetic resonance imaging (FMRI). Neurally, skewed gambles elicited more anterior insula activation than symmetric gambles equated for expected value and variance, and positively skewed gambles also specifically elicited more nucleus accumbens (NAcc) activation than negatively skewed gambles. Affectively, positively skewed gambles elicited more positive arousal and negatively skewed gambles elicited more negative arousal than symmetric gambles equated for expected value and variance. Subjects also preferred positively skewed gambles more, but negatively skewed gambles less than symmetric gambles of equal expected value. Individual differences in both NAcc activity and positive arousal predicted preferences for positively skewed gambles. These findings support an anticipatory affect account in which statistical properties of gambles—including skewness—can influence neural activity, affective responses, and ultimately, choice
Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
We find that a theoretical fit to all the HD 209458b data at secondary
eclipse requires that the dayside atmosphere of HD 209458b have a thermal
inversion and a stratosphere. This inversion is caused by the capture of
optical stellar flux by an absorber of uncertain origin that resides at
altitude. One consequence of stratospheric heating and temperature inversion is
the flipping of water absorption features into emission features from the near-
to the mid-infrared and we see evidence of such a water emission feature in the
recent HD 209458b IRAC data of Knutson et al. In addition, an upper-atmosphere
optical absorber may help explain both the weaker-than-expected Na D feature
seen in transit and the fact that the transit radius at 24 m is smaller
than the corresponding radius in the optical. Moreover, it may be a factor in
why HD 209458b's optical transit radius is as large as it is. We speculate on
the nature of this absorber and the planets whose atmospheres may, or may not,
be affected by its presence.Comment: Accepted to the Astrophysical Journal Letters on August 28, 2007, six
pages in emulateapj forma
Locations of Maximum Numbers of the Wheat Curl Mite, Aceria tulipae (K.) (Eriophyidae) on the Winter Wheat Plant during Spring Growth
Coincident with investigations on chemical control of wheat curl mite, Aceria tulipae (K.), a vector of wheat-streak mosaic, it was necessary that the area of heaviest and most uniform populations on the wheat plant be determined for mite counts. Both greenhouse screening trials and field application tests of miticides are being conducted currently. Since little is known concerning this mite, certain biological observations are recorded below for the information of other workers
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