The estimation of pointing angle and normalized surface scattering cross section from GEOS-3 radar altimeter measurements

The statistical error of the pointing angle estimation technique is determined as a function of the effective receiver signal to noise ratio. Other sources of error are addressed and evaluated with inadequate calibration being of major concern. The impact of pointing error on the computation of normalized surface scattering cross section (sigma) from radar and the waveform attitude induced altitude bias is considered and quantitative results are presented. Pointing angle and sigma processing algorithms are presented along with some initial data. The intensive mode clean vs. clutter AGC calibration problem is analytically resolved. The use clutter AGC data in the intensive mode is confirmed as the correct calibration set for the sigma computations

Crystal structure of the 3C protease from South African Territories type 2 foot-and-mouth disease virus

The replication of foot-and-mouth disease virus (FMDV) is dependent on the virus-encoded 3C protease (3Cpro). As in other picornaviruses, 3Cpro performs most of the proteolytic processing of the polyprotein expressed from the single open reading frame in the RNA genome of the virus. Previous work revealed that the 3Cpro from serotype A – one of the seven serotypes of FMDV – adopts a trypsin-like fold. Phylogenetically the FMDV serotypes are grouped into two clusters, with O, A, C, and Asia 1 in one, and the three South African Territories serotypes, (SAT-1, SAT-2 and SAT-3) in another. We report here the cloning, expression and purification of 3C proteases from four SAT serotype viruses (SAT2/GHA/8/91, SAT1/NIG/5/81, SAT1/UGA/1/97, and SAT2/ZIM/7/83) and the crystal structure at 3.2 Å resolution of 3Cpro from SAT2/GHA/8/91)

The room temperature phosphine-free synthesis of near-infrared emitting HgSe quantum dots

Luminescent mercury selenide (HgSe) quantum dots have been synthesised by a phosphine-free method using oleic acid as a capping agent. The modification of experimental conditions such as temperature resulted in particles of various sizes (15–100 nm) and morphologies not previously seen in HgSe, with emission tuneable between 1000 nm and 1350 nm

Study of cost/benefit tradeoffs for reducing the energy consumption of the commercial air transportation system

Economic studies were conducted for three general fuel conserving options: (1) improving fuel consumption characteristics of existing aircraft via retrofit modifications; (2) introducing fuel efficient derivations of existing production aircraft and/or introducing fuel efficient, current state-of-the-art new aircraft; and (3) introducing an advanced state-of-the-art turboprop airplane. These studies were designed to produce an optimum airline fleet mix for the years 1980, 1985 and 1990. The fleet selected accommodated a normal growth market by introducing somewhat larger aircraft while solving for maximum departure frequencies and a minimum load factor corresponding to a 15% investment hurdle rate. Fuel burnt per available-seat-mile flown would drop 22% from 1980 to 1990 due to the use of more fuel efficient aircraft designs, larger average aircraft size, and increased seating density. An inflight survey was taken to determine air traveler attitudes towards a new generation of advanced turboprops

Shapes of Molecular Cloud Cores and the Filamentary Mode of Star Formation

Using recent dust continuum data, we generate the intrinsic ellipticity distribution of dense, starless molecular cloud cores. Under the hypothesis that the cores are all either oblate or prolate randomly-oriented spheroids, we show that a satisfactory fit to observations can be obtained with a gaussian prolate distribution having a mean intrinsic axis ratio of 0.54. Further, we show that correlations exist between the apparent axis ratio and both the peak intensity and total flux density of emission from the cores, the sign of which again favours the prolate hypothesis. The latter result shows that the mass of a given core depends on its intrinsic ellipticity. Monte Carlo simulations are performed to find the best-fit power law of this dependence. Finally, we show how these results are consistent with an evolutionary scenario leading from filamentary parent clouds to increasingly massive, condensed, and roughly spherical embedded cores.Comment: 16 pages, incl. 11 Postscript figures. Accepted by Ap

ADOPTION OF BEST MANAGEMENT PRACTICES IN STOCKER CATTLE PRODUCTION

This study identifies current production and management practices of Oklahoma stocker cattle producers and analyzes factors affecting the adoption of best management practices (BMPs) using chi-square analysis. Results reveal that factors influencing the adoption of BMPs are operation size, dependency upon income from the operation, and specialization in stocker production.cattle, stockers, management, production, Livestock Production/Industries,

Optical Studies of Er-doped Yttrium Aluminium Garnet Phosphor Materials

The need for materials application in solid-state lasers, medical devices, and optoelectronic devices has made the investigation of ceramic materials of increasing importance. A detail study of the optical properties of rare earth element typically from luminescent materials when intentionally doped inside the host materials and in particular crystal (such as YAG) is reported for the photoluminescence, power and lifetime measurement. The rare-earth dopants usually form trivalent lanthanide ions and the energy transfer and optical transitions involved originate from 4f-4f transitions of the ions and between these states and the host material. In order to understand the energy transfer processes in more detail we need to better understand the accompanying optical processes that give rise to the emission they display and it is this that forms the focus of the work presented. Following this second (and higher) order processes are considered that lead to upconversion in erbium-doped yttrium aluminum garnet (Er:YAG) materials