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21.
Since 1950, Alberta oil production has been governed by production quotas, called proration. The nature and degree of the impact of proration on production efficiency is evaluated by applying a reservoir investment model and by comparing realized with minimum output costs. The main finding is that proration encouraged excessive investment in reservoirs of certain characteristics. The resulting substantial surplus investment would have been greater in the absence of other government regulations. The form of proration is important: earlier introduction of later measures would have produced significant savings.  相似文献   
22.
ABSTRACT: For regional precipitation frequency analyses, methods are needed to spatially interpolate or smooth point intensity duration frequency (IDF) estimates at gage sites for the purposes of visualization and estimation at ungaged sites. In this study to update IDF estimates for Michigan, the assumption is made that for practical purposes, the entire state may be treated as a homogeneous region in which annual maximum precipitation is identically distributed at each site apart from a site‐specific scaling factor, commonly known as the index flood. Several interpolation and smoothing techniques are evaluated for IDF estimation at ungaged sites, including trend surface analysis, thin plate splines, inverse distance weighting, and several kriging algorithms. Ordinary block kriging is recommended as a practical and objective method for smoothing the variability in the index flood values and developing isopluvial maps.  相似文献   
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Regulation and control of agricultural water pollution is unique and difficult to accomplish. Water quality standards are often proposed without adequate consideration of the overall economic impact on agricultural production. This article illustrates how economists and physical scientists can cooperate to develop appropriate control strategies for agricultural water pollution. Data provided by physical scientists and economists are used in a linear programming model to describe salt discharge as a function of water management, production levels, and an associated effluent charge. Four water management activities were chosen on the basis of different costs of production (including a parametrically varied effluent charge), water requirements, alfalfa yields, and levels of salt discharge. Results indicate that when the effluent charge is low (<$0.20/metric ton salt discharged), maximum production with maximum salt discharge is most profitable. As the effluent charge is increased ($0.20–$0.40/metric ton salt discharged), it becomes progressively less profitable to produce alfalfa at maximum levels of pollutant discharge. When the effluent charge is >$0.40/metric ton salt discharged, alfalfa production is no longer economically feasible. An important aspect of this approach is that it permits policy makers to identify explicitly the relationship between the environmental standard and the effect on agricultural production.  相似文献   
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Previous experimental work suggests flexibility in women’s mate preferences that appears to reflect the advantages of choosing healthy mates under conditions of pathogen threat and of choosing prosocial mates under conditions of resource scarcity. Following this work, we used an established priming paradigm to examine the effects of priming women’s concerns about pathogen threat versus resource scarcity on their judgments of men’s facial attractiveness and dominance. We found that women reported stronger attraction to masculine men when their concerns about pathogens were activated than when their concerns about resource scarcity were activated. In contrast, we found that women were more likely to ascribe high dominance to masculine men when their concerns about resource scarcity were activated than when their concerns about pathogens were activated. This latter result may reflect the greater importance of identifying men who pose a substantial threat to women’s resources and personal safety when resources are scarce and violence towards women is particularly common. Together, these findings suggest a double dissociation between the effects of pathogen threat and resource scarcity on women’s perceptions of the attractiveness and dominance of masculine men, potentially revealing considerably greater specialization (i.e., context specificity) in the effects of environmental threats on women’s perceptions of men than was apparent in previous research.  相似文献   
27.
The Exposure Opportunity Index (EOI) is a proximity-based model developed to estimate relative exposure of ground troops in Vietnam to aerially applied herbicides. We conducted a detailed quantitative evaluation of the EOI model by using actual herbicide spray missions isolated in time and space. EOI scores were calculated for each of 36 hypothetical receptor location points associated with each spray mission for 30 herbicide missions for two time periods – day of herbicide application and day 2–3 post-application. Our analysis found an enormous range of EOI predictions with 500–1000-fold differences across missions directly under the flight path. This quantitative examination of the EOI suggests that extensive testing of the model’s code is warranted. Researchers undertaking development of a proximity-based exposure model for epidemiologic studies of either Vietnam veterans or the Vietnamese population should conduct a thorough and realistic analysis of how precise and accurate the model results are likely to be and then assess whether the model results provide a useful basis for their planned epidemiologic studies.  相似文献   
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The European Water Framework Directive requires the integrated management of point and diffuse pollution to achieve 'good' water quality in 'protected areas'. These include bathing waters, which are regulated using faecal indicator organisms as compliance parameters. Thus, for the first time, European regulators are faced with the control of faecal indicator fluxes from agricultural sources where these impact on bathing water compliance locations. Concurrently, reforms to the European Union (EU) Common Agricultural Policy offer scope for supporting on-farm measures producing environmental benefits through the new 'single farm payments' and the concept of 'cross-compliance'. This paper reports the first UK study involving remedial measures, principally stream bank fencing, designed to reduce faecal indicator fluxes at the catchment scale. Considerable reduction in faecal indicator flux was observed, but this was insufficient to ensure bathing water compliance with either Directive 76/160/EEC standards or new health-evidence-based criteria proposed by WHO and the European Commission.  相似文献   
29.
Children constitute a vulnerable population and special considerations are necessary in order to provide proper care for them during disasters. After disasters such as Hurricane Katrina, the rapid identification and protection of separated children and their reunification with legal guardians is necessary in order to minimise secondary injuries (i.e. physical and sexual abuse, neglect and abduction). At Camp Gruber, an Oklahoma shelter for Louisianans displaced by Hurricane Katrina, a survey tool was used to identify children separated from their guardians. Of the 254 children at the camp, 36 (14.2 per cent) were separated from their legal guardians. Answering 'no' to the question of whether the accompanying adult was the guardian of the child prior to Hurricane Katrina was a strong predictor (27.8 per cent versus 3.2 per cent) of being listed as 'missing' by the National Center for Missing and Exploited Children (NCMEC). All the children at Camp Gruber who were listed as 'missing' by the NCMEC were subsequently reunited with their guardians.  相似文献   
30.
Woodchip corrals are increasingly used as cost effective means of over-wintering livestock in temperate regions but there is little information on their potential environmental impact. Four woodchip corrals of varying characteristics were instrumented to capture and quantify the flows reaching the base, where pollutant fluxes may move either vertically to groundwater, or laterally to a water course. Samples for chemical analysis were collected daily by auto-sampler. Samples for bacterial analysis were aseptically hand-sampled. Sampling frequency was increased during high flow events and sampling was conducted over a 12-month period. Microbiological samples were analysed for total coliform (TC), presumptive Escherichia coli (EC) and intestinal enterococci (IE). Leachate was also analysed for total phosphorus, phosphate, total nitrogen, ammonium, total oxidised nitrogen, nitrite and nitrate. Each corral had a recording rain gauge sited within 10 m of the corral surface. Mean total nitrogen concentration in leachate was 339.5 mg l(-1), of which ammoniacal-N comprised approximately 57%. Mean total phosphorus concentration was 94.7 mg l(-1). Geometric mean concentrations of TC, EC and IE were 95,461, 94,983 and 55,552 cfu100 ml(-1), respectively. Significant flows of leachate occurred at the base of the corrals on most days during the 1-year sampling period and flow rate increased with stocking density. Strong positive linear relationships were found between the concentrations of the nutrient parameters and discharge. Strong positive curvilinear relations were found between faecal indicator concentrations and discharge. Different relationships were observed in the stocked and unstocked corrals. The resulting fluxes are sufficient to give concern and to indicate that corral development is worthy of regulatory attention.  相似文献   
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