Attitudes of Georgia Irrigators Regarding the Use of Water Meters

The primary purpose of this paper is to provide information, in terms of these three stages, about the position of Georgia irrigators with regard to the adoption of water meters. Understanding where farmers are in the HEM can be useful to policy makers in deciding the mix of promotion, incentives, and regulation needed to encourage the adoption of water meters. Working Paper # 2003-00

Prison guards’ attitudes towards the prevention of sexual contacts between inmates

This article presents the main findings of an innovative Portuguese research project on prison guards’ attitudes towards the prevention of sexual contacts between inmates. Sexuality in prisons is still a poorly-studied issue, although its increasing visibility demands a better understanding of prison dynamics. Results show that guards hold very favourable attitudes towards the prevention of forced sexual contacts between inmates, but they are more ambiguous concerning consensual sexuality. This result is influenced by the characteristics of the inmates under the guards’ supervision and by the prison guards’ knowledge of the existence of sexual contacts between inmates. The results will be discussed, along with their impact on the development of training programmes and policies regarding sexual contacts between inmate

The Interaction of Chlorophyll a with Lipids in Model and Natural Membrane Systems

Chlorophyll a is the principal photosynthetic pigment of plants and most algae. Despite its importance relatively little is known about its organization or environment within the photosynthetic membrane. A variety of evidence suggests that a significant portion of the chlorophyll may be associated with the lipid portion of the photosynthetic thylakoid membrane. The topic of the interaction of chlorophyll with lipid membranes, both model and natural, forms the basis of this thesis. It is found that chlorophyll a can be incorporated into model phospholipid bilayer membranes at up to 40 mole percent. Both multilamellar and small vesicular bilayer forms can be prepared and characterized. The phase diagram of the chlorophyll a/distearoylphosphatidylcholine (DSPC) bilayer system, obtained by differential thermal analysis, is complex and indicates that below the solidus phase transition chlorophyll a and DSPC form a compound phase with a composition of 40 mole pe-rcent chlorophyll a. A thermodynamic simulation of the phase diagram yields an estimate for the strength of the chlorophyll a-DSPC interaction. Nuclear magnetic resonance studies, utilizing the shift effect on nearby nuclei due to the large ring current magnetic anisotropy of chlorophyll, demonstrate that compound formation results from a coordination interaction between the DSPC phosphate and the central magnesium atom of chlorophyll a which has an obligatory requirement for an additional axial ligand. The optical properties of chlorophyll a are modified by its inclusion into bilayers and change at the bilayer phase transition. Compared to chlorophyll a in organic solution, chlorophyll a in bilayers has absorption maxima which are strongly red-shifted and a greatly reduced fluorescence. The red-shift is most pronounced and fluorescence is lowest below the solidus phase transition temperature. Several possible causes of these changes in optical properties are discussed. Because the optical properties of chlorophyll a/DSPC bilayers in the compound phase duplicate the optical properties of bulk in vivo chlorophyll quite well, this system constitutes an attractive model of the photosynthetic chlorophyll antenna. Evidence for the location of a pool of chlorophyll in a lipid environment comes from the 13C-NMR spectrum at 90.5 MHz of the photosynthetic thylakoid membrane from spinach. Specific lipid and chlorophyll resonances are observed and assigned but no protein resonances are found. It can be estimated that at least 30% of the plant chlorophyll contributes to the high resolution spectrum with the remainder presumably broadened by association with membrane proteins. The resonance linewidths of the observed chlorophyll phytol chains are approximately the same as those of the lipid hydrocarbon chains indicating that their motional states are similar and suggesting that this fraction of chlorophyll is lipid bound or at most only loosely associated with membrane proteins.</p

Resistivity Arrays as an Early Warning System for Monitoring Runoff Holding Ponds

Monitoring wells are installed to intercept contaminants inadvertently discharged from inground structures designed to retain salt-affected wastewaters; however, several difficulties with collection and data interpretation limit their effectiveness. Therefore, improved monitoring methods are needed. The objective of this study was to evaluate the effectiveness of resistivity array technology as an early warning system to monitor for unintended basin discharge. Subsurface resistivity arrays were installed at two Nebraska sites: a beef cattle feedyard located at the U.S. Meat Animal Research Center, Clay Center, Nebraska (FyA) and a commercial cattle feeding operation (FyB). Monitoring well data did not identify any unintended discharge events during the study period. However, the resistivity array (RA) system detected a discharge event that was localized in the non-saturated zone adjacent to the pond at FyB within one day following a precipitation event. Monitoring the unsaturated portion allows the RA system a capacity beyond traditional monitoring wells, which can only intercept discharge carried in groundwater. Also, the RA system effectively measured a larger area (i.e., a virtual curtain) compared to the point measure typical of monitoring wells. Therefore, RA technology provides broader coverage and is more tolerant to placement issues for intercepting discharge. Finally, the capacity to automate the RA system provides a means to continuously monitor unintended subsurface discharge from runoff holding ponds. This continuous monitoring system is more likely to detect discharge events than the bi-annual sampling typically required for monitoring wells. Automatic and continuous monitoring provides feedyard operators options to better manage environmental impacts associated with runoff holding ponds

Soil-Crop Dynamic Depth Response Determined from TDR of a Corn Silage Field Compared to EMI Measurements

Electromagnetic induction (EMI) techniques have been used to monitor bulk seasonal soil-crop apparent electrical conductivity (ECa) dynamics. Interpreting this information can be complicated by changes in the soil profile such as water content or nutrient leaching. Time domain reflectometry (TDR) measures localized soil EC; therefore, TDR can provide clarification to where in the soil profile the EC changes are taking place. The objective of this study was to determine whether surface or deep EC changes were driving the response measured by EMI during the crop season of a field amended with animal manure. Results indicate that seasonal soil-crop EC dynamics measured by EMI are primarily driven by surface (,0.2 m) changes as opposed to deeper (.0.9 m) changes. These changes appear to be the result of surface ionic dynamics caused by crop-soil interactions and not soil volumetric water content (hv), since no significant correlations were detected between hv and ECa for any treatment, depth or dipole orientation. These findings are consistent with others who reported the EMI signal was driven primarily by changes in nitrate concentration and not by soil water content. The results of this study clarify our understanding of the soil dynamics that drive the ECa response of a manure amended field. The ability to non-intrusively measure nutrient mineralization and crop uptake provides researchers with a powerful tool for understanding soil-crop interactions. Understanding the soil-crop dynamic will facilitate development of management practices for amending soil with manure while protecting the environment from unintended contamination

Energy and Nutrient Recovery fromCattle Feedlots

Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed using a subsurface sensor (Dualem-1S, Milton, ON) and software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VSs) then combined with the Dualem-1S apparent soil conductivity (ECa) data to produce models having correlations between associated ECa values and VS (r2 = 0.869, VS). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or cocombustion

A Comparison of Electromagnetic Induction Mapping to Measurements of Maximum Effluent Flow Depth for Assessing Flow Paths in Vegetative Treatment Areas

Vegetative treatment systems (VTSs) are one type of control structure that has shown potential to control runoff from open feedlots. To achieve maximum performance, sheet-flow over the width of the vegetative treatment area (VTA) is required. Tools, such as maps of flow paths through the VTA, are needed to aid producers in locating concentrated flow paths and in determining the most effective approach to redistribute flow. Members of the USDA-ARS USMARC laboratory have developed remote sensing techniques using Electromagnetic Induction (EMI) to measure spatial nutrient distribution, and identify possible flow paths, within VTAs. The objective of this study was to determine whether apparent soil electrical conductivity maps can be used to locate concentrated flow paths in the VTA. Effluent flow paths in the VTA were determined by measuring the maximum height of flow at different locations within the VTA. In this study, PVC stakes were coated with a water sensitive paint and located throughout the treatment area during effluent release from solid settling basin to the VTA. The maximum depth of flow at each stake was recorded following a release event from the settling basin. The flow maps generated from the data were compared to ECa maps measuring salt build-up in the soil due to basin discharge. The flow paths identified in the EMI maps were generally in agreement with measured water depths in the VTA. Therefore, techniques that use EMI technology can be used by regulators to monitor VTS performance, by design engineers to improve system performance, and by producers to better manage their systems

Soil-Crop Dynamic Depth Response Determined from TDR of a Corn Silage Field Compared to EMI Measurements

Electromagnetic induction (EMI) techniques have been used to monitor bulk seasonal soil-crop apparent electrical conductivity (ECa) dynamics. Interpreting this information can be complicated by changes in the soil profile such as water content or nutrient leaching. Time domain reflectometry (TDR) measures localized soil EC; therefore, TDR can provide clarification to where in the soil profile the EC changes are taking place. The objective of this study was to determine whether surface or deep EC changes were driving the response measured by EMI during the crop season of a field amended with animal manure. Results indicate that seasonal soil-crop EC dynamics measured by EMI are primarily driven by surface (,0.2 m) changes as opposed to deeper (.0.9 m) changes. These changes appear to be the result of surface ionic dynamics caused by crop-soil interactions and not soil volumetric water content (hv), since no significant correlations were detected between hv and ECa for any treatment, depth or dipole orientation. These findings are consistent with others who reported the EMI signal was driven primarily by changes in nitrate concentration and not by soil water content. The results of this study clarify our understanding of the soil dynamics that drive the ECa response of a manure amended field. The ability to non-intrusively measure nutrient mineralization and crop uptake provides researchers with a powerful tool for understanding soil-crop interactions. Understanding the soil-crop dynamic will facilitate development of management practices for amending soil with manure while protecting the environment from unintended contamination