A convenient telescope performance metric for imaging through turbulence

This paper provides an overview of the various image quality metrics used in astronomical imaging and explains in details a new metric, the Normalized Point Source Sensitivity. It is based on the Equivalent Noise Area concept, an extension of the EE80% metric and is intuitively linked to the required science integration time. As it was proved in recent studies, the PSSN metric properly accounts for image degradation due to the spatial frequency content of a given telescope aberration and the effects of various errors can be multiplicatively combined, like those expressed in Central Intensity Ratio. Extensions of the metric for off-axis imaging and throughput degradation are presented. Wavelength and spatial frequency dependence of PSSN are discussed. While the proper calculation of the PSSN metric requires the precise knowledge of the PSF of both the optics and atmosphere, there is a straightforward approximation linking PSSN to the Zernike decomposition of the OPD. Besides the summary of various aspects of the Point Source Sensitivity, the paper provides many numerical examples derived for the Thirty Meter Telescope

34th Annual Bible Lectureship -- Heritage and Destiny: A Study of the Restoration Movement (1977)

Program booklet for the 34th Annual Pepperdine Bible Lectures, held at Pepperdine University in Malibu, California, April 17-20, 1977. The Pepperdine Bible Lectures is an annual event hosted by Pepperdine University featuring a wide variety of lectures and classes on topics and themes in the Bible and Christianity. Carl Mitchell, Directorhttps://digitalcommons.pepperdine.edu/churches/1062/thumbnail.jp

36th Annual Bible Lectureship -- It\u27s Great to Be a Christian! (1979)

Program booklet for the 36th Annual Pepperdine Bible Lectures, held at Pepperdine University in Malibu, California, April 15-18, 1979. The Pepperdine Bible Lectures is an annual event hosted by Pepperdine University featuring a wide variety of lectures and classes on topics and themes in the Bible and Christianity. Carl G. Mitchell, Directorhttps://digitalcommons.pepperdine.edu/churches/1061/thumbnail.jp

37th Annual Bible Lectureship -- For Such a Time as This (1980)

Program booklet for the 37th Annual Pepperdine Bible Lectures, held at Pepperdine University in Malibu, California, April 13-16, 1980. The Pepperdine Bible Lectures is an annual event hosted by Pepperdine University featuring a wide variety of lectures and classes on topics and themes in the Bible and Christianity. Carl Mitchell, Directorhttps://digitalcommons.pepperdine.edu/churches/1064/thumbnail.jp

Tidal Disruptions of Stars by Black Hole Remnants in Dense Star Clusters

In a dense stellar environment, such as the core of a globular cluster (GC), dynamical interactions with black holes (BHs) are expected to lead to a variety of astrophysical transients. Here we explore tidal disruption events (TDEs) of stars by stellar-mass BHs through collisions and close encounters. Using state-of-the-art $N$-body simulations, we show that these TDEs occur at significant rates throughout the evolution of typical GCs and we study how their relative rates relate to cluster parameters such mass and size. By incorporating a realistic cosmological model of GC formation, we predict a BH - main-sequence-star TDE rate of approximately $3\,\rm{Gpc}^{-3}\,\rm{yr}^{-1}$ in the local universe ($z<0.1$) and a cosmological rate that peaks at roughly $25\,\rm{Gpc}^{-3}\,\rm{yr}^{-1}$ for redshift 3. Furthermore, we show that the ejected mass associated with these TDEs could produce optical transients of luminosity $\sim 10^{41} - 10^{44}\rm\,erg\,s^{-1}$ with timescales of about a day to a month. These should be readily detectable by optical transient surveys such as the Zwicky Transient Facility. Finally, we comment briefly on BH - giant encounters and discuss how these events may contribute to the formation of BH - white-dwarf binaries.Comment: Accepted for publication in ApJ. Comments welcom

Inability of Diapausing Culex pipiens (Diptera: Culicidae) to Use Blood for Producing Lipid Reserves for Overwinter Survival

Diapausing Culex pipiens L. females fed 10% sucrose for 7 d following eclosion contained significantly more lipids (P < 0.05) than nondiapausing females reared and maintained at the same temperature (22°C) but at a longer photophase (14:10 [L:D] instead of 9:15). Diapausing females with limited lipid reserves failed to increase their reserves after blood feeding. The average lipid content of 56 females tested decreased significantly (P < 0.05) by day 6 after feeding and there was no correlation (r = −0.06) between lipid content at this time and original bloodmeal volumes of individual females. These results refute the contention that blood meals taken by diapausing Cx. pipiens result in fat body development when females are incubated at 18°C during bloodmeal digestion. Diapausing Cx. pipiens with limited lipid reserves were unable to obtain sufficient energy from a single blood meal to survive extended hibernation. Although none became gravid, only 50% remained alive after 20 d in hibernation. In contrast, nonblood-fed females fed only 10% sucrose for 7 to 10 d before being placed in hibernation on a water diet survived for 6 mo with only 50% mortality. There was no evidence for gonotrophic dissociation. Failure of blood-fed, diapausing females to initiate vitellogenesis was correlated with the significantly smaller blood meals taken by most diapausing females and not with hypertrophy of the fat body or temperature during digestio

Fate of the Blood Meal in Force-Fed, Diapausing Culex pipiens (Diptera: Culicidae)

Diapausing Culex pipiens L. do not display host-seeking behavior and can be induced to take blood only by being placed in contact with or in proximity to a host for prolonged periods. Such "force-fed” females do not use the blood for lipogenesis, and only some of them use the blood to initiate vitellogenesis. Diapausing Cx. pipiens that are induced to feed eject an average of 4.2-4.6 μl of blood during overnight feeding periods compared with an average of 0.1 μl for nondiapausing controls. The reduced avidity of diapausing females for blood, even under optimum conditions, and the ejection by fed females of blood volumes in excess of volumes usually retained indicate that such females are not physiologically programmed for taking and retaining blood. Data for uric acid and hematin excretion and bloodmeal volumes retained by diapausing females are positively correlated with diapause termination and yolk deposition. The occurrence of gonotrophic dissociation need not be invoked to explain the failure of some diapausing females to initiate vitellogenesis following a blood meal. Instead, this is explained by retention of small quantities of blood followed by incomplete digestion and is the expected result of a dose-dependent phenomenon determined by threshold blood volumes. Our data support the concept that the overwintering strategy of Cx. pipiens is limited to gonotrophic concordance in which overwintering females in nature do not take blood or develop eggs until diapause is terminate

MWIR and LWIR Spectral Signatures of Water and Associated Materials

Spectral infrared emissivity measurements have been made of a variety of materials both with and without surface water. The surface water was either natural, in the form of dew or residual rainwater, or artificially introduced by manual wetting. Materials naturally high in water content were also measured. Despite the rather diverse spectral population of the underlying materials, they exhibited very similar, featureless, water-like spectra; spectrally flat with a very high magnitude across the emissive infrared region. The implication to exploitation personnel that may use emissive infrared hyperspectral image data is that in areas where condensation is likely (e.g. high humidity) or in areas populated with high water content background materials (e.g. highly vegetated areas), discrimination may prove an intractable problem with hyperspectral infrared sensing for ambient temperature targets. A target that exhibits a temperature either below or above ambient temperature may be detectable, but not identified, and may be more economically pursued with a far simpler, single-band midwave or longwave sensor