6,268 research outputs found
Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 Filter
We present a revised effective wavelength and photometric calibration for the
Wide-field Infrared Survey Explorer (WISE) W4 band, including tests of
empirically motivated modifications to its pre-launch laboratory-measured
relative system response curve. We derived these by comparing measured W4
photometry with photometry synthesised from spectra of galaxies and planetary
nebulae. The difference between measured and synthesised photometry using the
pre-launch laboratory-measured W4 relative system response can be as large as
0.3 mag for galaxies and 1 mag for planetary nebulae. We find the W4 effective
wavelength should be revised upward by 3.3%, from 22.1 micron to 22.8 micron,
and the W4 AB magnitude of Vega should be revised from m = 6.59 to m = 6.66. In
an attempt to reproduce the observed W4 photometry, we tested three
modifications to the pre-launch laboratory-measured W4 relative system response
curve, all of which have an effective wavelength of 22.8 micron. Of the three
relative system response curve models tested, a model that matches the
laboratory-measured relative system response curve, but has the wavelengths
increased by 3.3% (or 0.73 micron) achieves reasonable agreement between the
measured and synthesised photometry.Comment: Accepted for publication in Publications of the Astronomical Society
of Australia, 6 pages, 4 figures, 1 tabl
The Influence of Religiosity, Gender, and Language Preference Acculturation on Sexual Activity Among Latino/a Adolescents
The purpose of this study was to determine the main and interactive effects of religiosity, gender, and language preference acculturation on sexual activity among 570 Latino/a adolescents from the 2002 National Survey of Family Growth. Results indicated that adolescents who viewed religion as very important, had frequent church attendance, and had more traditional attitudes on sexuality were less likely ever to have sex compared with adolescents who were less religious. Those with frequent church attendance and high traditional attitudes had fewer lifetime and recent sex partners. Unassimilated religious youth were less likely ever to have sex, had fewer lifetime and recent sexual partners, and a later age of sexual debut. Females were less likely to have had sex, had fewer recent and lifetime partners, and had a later age of coital debut than males. Religiosity had a healthy dampening of sexual activity among Latino/a adolescents and, in particular, among those who were less assimilated
Bending and Breathing Modes of the Galactic Disk
We explore the hypothesis that a passing satellite or dark matter subhalo has
excited coherent oscillations of the Milky Way's stellar disk in the direction
perpendicular to the Galactic midplane. This work is motivated by recent
observations of spatially dependent bulk vertical motions within ~ kpc of the
Sun. A satellite can transfer a fraction of its orbital energy to the disk
stars as it plunges through the Galactic midplane thereby heating and
thickening the disk. Bulk motions arise during the early stages of such an
event when the disk is still in an unrelaxed state. We present simple toy-model
calculations and simulations of disk-satellite interactions, which show that
the response of the disk depends on the relative velocity of the satellite.
When the component of the satellite's velocity perpendicular to the disk is
small compared with that of the stars, the perturbation is predominantly a
bending mode. Conversely, breathing and higher order modes are excited when the
vertical velocity of the satellite is larger than that of the stars. We argue
that the compression and rarefaction motions seen in three different surveys
are in fact breathing mode perturbations of the Galactic disk.Comment: 12 pages, 12 figure
The Discovery of Trissolcus japonicus (Hymenoptera: Scelionidae) in Michigan
The invasive brown marmorated stink bug, Halyomorpha halys (Stål), is a pest of growing economic importance in the United States, the control of which currently relies on pesticide applications. Biological control could provide sustainable and long-term control but classical biological control agents have not yet been approved. Adventive populations of a potential biological control agents, the Samurai wasp, Trissolcus japonicus (Ashmead), have been found in the United States, first in Maryland in 2014, expanding its range west to Ohio by 2017. Trissolcus japonicus is a highly effective parasitoid of H. halys eggs, but its redistribution and augmentative releases are restricted to states where it has been detected in the wild. To assess the presence of T. japonicus in Michigan and attack rates of H. halys by native natural enemies we deployed 189 H. halys egg masses at ten sites in lower Michigan between May and October in 2018. In addition, we deployed 51 native stink bug egg masses at the same sites to evaluate potential non-target effects of T. japonicus in the field, which were shown to occur in laboratory studies. We found T. japonicus in a single H. halys egg mass, which constitutes the first record of this Asian parasitoid in Michigan. Native predators and parasitoids caused minimal mortality of H. halys eggs and we did not find evidence of non-target effects of T. japonicus on native stink bug species. These findings open the door to initiation of a classical biological control program using an efficient, coevolved parasitoid from the native range of H. halys
Evolution of replication efficiency following infection with a molecularly cloned feline immunodeficiency virus of low virulence
The development of an effective vaccine against human immunodeficiency virus is considered to be the most practicable means of controlling the advancing global AIDS epidemic. Studies with the domestic cat have demonstrated that vaccinal immunity to infection can be induced against feline immunodeficiency virus (FIV); however, protection is largely restricted to laboratory strains of FIV and does not extend to primary strains of the virus. We compared the pathogenicity of two prototypic vaccine challenge strains of FIV derived from molecular clones; the laboratory strain PET<sub>F14</sub> and the primary strain GL8<sub>414</sub>. PET<sub>F14</sub> established a low viral load and had no effect on CD4<sup>+</sup>- or CD8<sup>+</sup>- lymphocyte subsets. In contrast, GL8<sub>414</sub> established a high viral load and induced a significant reduction in the ratio of CD4<sup>+</sup> to CD8<sup>+</sup> lymphocytes by 15 weeks postinfection, suggesting that PET<sub>F14</sub> may be a low-virulence-challenge virus. However, during long-term monitoring of the PET<sub>F14</sub>-infected cats, we observed the emergence of variant viruses in two of three cats. Concomitant with the appearance of the variant viruses, designated 627<sub>W135</sub> and 628<sub>W135</sub>, we observed an expansion of CD8<sup>+</sup>-lymphocyte subpopulations expressing reduced CD8 ß-chain, a phenotype consistent with activation. The variant viruses both carried mutations that reduced the net charge of the V3 loop (K409Q and K409E), giving rise to a reduced ability of the Env proteins to both induce fusion and to establish productive infection in CXCR4-expressing cells. Further, following subsequent challenge of naïve cats with the mutant viruses, the viruses established higher viral loads and induced more marked alterations in CD8<sup>+</sup>-lymphocyte subpopulations than did the parent F14 strain of virus, suggesting that the E409K mutation in the PET<sub>F14</sub> strain contributes to the attenuation of the virus
Erratum: "Groups of Galaxies in the Two Micron All Sky Redshift Survey" (ApJ, 655, 790 [2007])
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