A GSD ESTIMATION OF THE RELATIVE WORTH OF COVER CROPS IN COTTON PRODUCTION SYSTEMS

Cover crops can help reduce the negative environmental impacts of cotton production. Using time series yield data, this study utilizes generalized stochastic dominance to evaluate the relative worth, via risk premiums, of three cover crop and two conventional production systems based on expected net returns of each system and decision maker risk attitude. Results indicate, within the limitation of the study, two cover crop regimes possess a high degree of dominance over conventional systems. Determination of the dominant regime depends upon the risk attitude of a specific decision maker. This research suggests cover crop production systems may be feasible alternatives to conventional practices.Crop Production/Industries, Environmental Economics and Policy,

BIOECONOMIC MODELING OF THE GULF SHRIMP FISHERY: AN APPLICATION TO GALVESTON BAY AND ADJACENT OFFSHORE AREAS

Resource /Energy Economics and Policy,

Physiology of Sporeforming Bacteria Associated with Insects: Radiorespirometric Survey of Carbohydrate Metabolism In the 12 Serotypes of \u3ci\u3eBacillus thuringiensis\u3c/i\u3e

Radiorespirometry was used to compare the primary pathways of glucose catabolism in 18 strains of Bacillus thuringiensis representing the 12 established serotypes. Every strain utilizes the Embden-Meyerhof-Pamas pathway almost exclusively; pentose-phosphate pathway participation is minor. The Embden- Meyerhof-Parnas pathway predominates regardless of whether the cells were grown in a minimal medium or one containing yeast extract. The results indicate that the absolute requirement for citrate and related compounds is not a result of defective citrate or glucose transport and metabolism

An Assessment of Water Sources Related to Major Systems of Agricultural Land Use in Kentucky

Recent years have seen a greater public concern about the quality of the nation\u27s water resources. While initial concerns targeted point source pollution, the emphasis in recent years has shifted to non-point source pollution, including the effect of general practices used by fanners in agricultural production systems. Since there was no reliable data base on such effects for Kentucky, the state\u27s General Assembly passed legislation during its 1990 session directing the University ofKentucky\u27s College of Agriculture (UK.CA) to assess the effect of agricultural practices on quality of the state\u27s waters. As part of the efforts undertaken by the UKCA in this regard, an assessment was made of water sources in major agricultural areas to determine the current level of water quality associated with agricultural practices in those areas. This information was needed to evaluate the question of concern: Do nonpoint agricultural practices such as fertilizer and herbicide use and grazing of pastures by livestock pose a threat to the quality of water potentially serving as human drinking water sources

Photodetector Focal Plane Arrays Integrated with Silicon Micropyramidal Structures in MWIR

Light-concentrating truncated Si micropyramidal arrays with 54.7 degree sidewall angles were successfully integrated with PtSi Schottky barrier photodetectors. Four different devices consisting of 10 x 10 photodetectors with 60 um pitch combined in parallel were tested, where significant enhancement capability was demonstrated by the Si micropyramids. The device consisting of one hundred 22 um square detectors monolithically integrated with the light-concentrating micropyramidal array displayed signal enhancement of up to 4 times compared to the same size 22 um square photodetector device without the light concentrators.Comment: 4 pages, 2 figures, GOMACTech 202

Focusing and Diffraction of Light by Periodic Si Micropyramidal Arrays

This research was devoted to modeling of the optical properties of Si micropyramids aimed at designing optimal structures for applications as light concentrators in mid-wave infrared (MWIR) focal place arrays (FPAs). It is shown that completely different optical properties of such structures can be realized using two types of boundary conditions (BCs): i) periodical and ii) perfectly matched layer. The first type (periodical BC) allowed us to describe the Talbot effect under plane wave coherent illumination conditions. This effect was experimentally demonstrated in the proposed structures. The second type (perfectly matched layer BC) allows describing the optical properties of individual micropyramids concentrating or focusing light on the photodetector. The optimal geometries of micropyramids required for maximizing the intensity of photonic nanojets emerging from their truncated tips are determined.Comment: 4 pages, 5 figures, GOMACTech 202

One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions: Crossed Aldehyde-Aldehyde Coupling, Thioester Substrates, and Reactions in Ester Solvents

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield b- hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely observed

Characterization of subsurface media from locations up- and down-gradient of a uranium-contaminated aquifer.

The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments