Near-infrared observations of Venus

Ground-based near-infrared observations of the Venus night side reveal anomalous bright features at wavelengths near 1.7 and 2.3 micrometer (Allen and Crawford, 1984; Allen, 1987). These features are thought to be formed as thermal radiation from the hot lower atmosphere leaks through holes in the middle and/or lower sulfuric acid cloud decks. Because these holes allow radiation to escape from deep in the troposphere, they provide an opportunity to significantly improve our understanding of the composition, thermal structure, and dynamics of this region of the Venus atmosphere. New near-infrared observations of the Venus night side are needed to address these questions. During the first year of this program, researchers requested and received observing time at six sites and organized a highly-skilled team. The wide array of sites should allow researchers to collect the data needed to meet all of the proposed objectives. High resolution spectra of the Venus night side was obtained. Researchers are currently collecting the first images of Venus from Kitt Peak and Table Mountain. The state-of-the-art infrared array detectors that are being used at these sites are allowing researchers to collect hundreds of high-quality images during each observing day. These images show the expected bright features, but they have not yet begun to track these features

The Inhomogeneous Hall's Ray

We show that the inhomogenous approximation spectrum, associated to an irrational number \alpha\ always has a Hall's Ray; that is, there is an \epsilon>0 such that [0,\epsilon) is a subset of the spectrum. In the case when \alpha\ has unbounded partial quotients we show that the spectrum is just a ray.Comment: Fixed typos in bibliograph

Groundbased near-IR observations of the surface of Venus

We present images of the nightside of Venus taken in the near-infrared windows at 1.0, 1.1, 1.18, 1.28, 1.31, and 2.3 microns with the new infrared camera/spectrometer IRIS on the Anglo-Australian Telescope. These data were taken in spectral-mapping mode. This technique involves scanning the telescope perpendicular to the slit, while collecting spectra at successive slit positions across the planet. We produce data cubes with one spectral and two spatial dimensions. Images can be extracted over any wavelength regions. Each image has square pixels of 0.8 inch resolution. We reduced the scattered light from the sunlit crescent in images extracted from each window by subtracting images taken on either side of the window, where the Venus atmosphere is opaque. Unlike the short wavelength windows, which reveal thermal contrasts that originate primarily from the surface and deep atmosphere, the emission in the 2.3 microns window is produced at much higher altitudes (30-40 km). Emission contrasts seen near 2.3 microns are associated with horizontal variations in the cloud optical depths, and have rotation periods of about six days. We detect large contrasts in infrared emission (20-40 percent) across the disc of Venus in the 1.0-, 1.1-, 1.18-, 1.28-, and 1.31-micron images. Contrasts at these wavelengths may be due to a combination of variations in the optical depths of the overlying sulfuric acid clouds and differences in surface emission. Comparison with the 2.3-micron images show that the patterns seen in the 1.28- and 1.31-micron windows are consistent with cloud optical depth variations alone and require no contribution from the surface. However, images at 1.0, 1.1, and 1.8 microns from July 1991 show a dark feature having a contrast that increases with decreasing wavelength. This behavior is contrary to that expected of cloud absorption. Images taken on three successive days in October show another dark feature that is stationary with respect to the surface. These regions of lower emission correspond closely to the high-altitude surface regions of Beta Regio and Aphrodite Terra. The images can potentially reveal the near-infrared emissiveity of the surface of Venus, thereby complementing Magellan radar reflectivity and ground based radio emissivity measurements. The contrast ratio between highlands and plains is much smaller than would be expected for blackbody radiation from the surface along. Unlike at radio wavelengths, where the atmosphere is essentially transparent, at near-infrared wavelengths the atmosphere emits, absorbs, and scatters radiation, and can modify the observed topographically induced contrasts. The additional radiation from the atmosphere reduces the contrast, and further modification would be expected if terrain at different altitudes has different emissivities. A fit to our data therefore requires, and may constrain, a model of the lowest scale height of the atmosphere

Studies on the biology of some species of British corixidae

The life history of the water-bug, Corixa germari (Fieb.) was studied quantitatively in a Derbyshire reservoir and observations on the biology of the species were also made. The eggs of C.germari are firmly attached to stones and are laid chiefly on the undersides or in crevices. The oviposition rate and egg mortality during 1958 were estimated by direct counts of eggs in the field, the abundance of the adults and nymphs was measured in terms of a Standard Net Sweep and the number of eggs laid per female per season was calculated from these data. By means of these methods, it was found that in I958 the breeding adults gave mean catches of 10 per Standard Net Sweep (43% of the adults were females) and that these adults produced 916 eggs. About 530 hatched and, of the nymphs produced, about 80 survived to become adults in the autumn. About 20 of these survived to breed in 1959. Estimates of the density of eggs laid per m(^2) of substratum in 1958 show that the catch per Standard Net Sweep represents about 1/38 of the number of C.germari per m(^2) of substratum. By weighing the various stages in the life history it was shown that the standing crop of C.germari gives a biomass value of2about 20 g. dry weight per m of substratum in the autumn. This is the highest value reached in the course of the season. C.germari has been shown to live at greater depths than most other British species and this may be a means of avoiding the the effects of wave action. Its ability to exploit deep water is coupled with the fact that it visits the surface less often and swims more rapidly than certain shallow water species

Infant baptism and the disposition to saving faith

The research that went into the composition of this article was made possible through the support of a grant from the John Templeton Foundation.Reformed accounts of infant baptism are usually covenantal and promissory in nature. They are about bringing the child into the ambit of the visible church in the hope the infant will own the faith upon reaching the age of reason. This paper sets out an alternative Reformed account of baptism, drawing on the Scottish confessional tradition. On this account, infants have a disposition to faith conveyed to them in baptism that will in due course become dispositional faith exercised in saving faith. Thus, baptism involves regeneration – or something close to it.Publisher PDFPeer reviewe

Theology and the university : a reply to Professor Wolfe

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T. F. Torrance on theosis and universal salvation

T. F. Torrance is widely thought to be one of the most important recent theologians in the Anglophone world. There has been quite a lot of research done on his soteriology. This essay contributes to that discussion by assessing five soteriological themes in his thought. These comprise: his account of the vicarious humanity of Christ, the notion of incarnation as atonement, his christological understanding of the divine image, his wholly objective view of the nature of justification and his atonement mechanism. I use this analysis as a means to investigate two broader notions in his theology. These are theosis and universal salvation. In keeping with several other recent treatments of his work I conclude his theology implies a doctrine of theosis. I also argue that it implies universalism, despite his emphatic rejection of the doctrine.Publisher PDFPeer reviewe