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141.
ABSTRACT: Driven by increasing concerns about bacterial pollution from agricultural sources, states such as Virginia have initiated cost sharing programs that encourage the use of animal waste best management practices (BMPs) to control this pollution. Although a few studies have shown that waste management BMPs are effective at the field scale, their effectiveness at the watershed scale and over the long term is unknown. The focus of this research was to evaluate the effectiveness of BMPs in reducing bacterial pollution at the watershed scale and over the long term. To accomplish this goal, a 1,163 ha watershed located in the Piedmont region of Virginia was monitored over a ten‐year period. Fecal coliforms (FC) and fecal streptococci (FS) were measured as indicators of bacterial pollution. A pre‐BMP versus post‐BMP design was adopted. Major BMPs implemented were manure storage facilities, stream fencing, water troughs, and nutrient management. Seasonal Kendall trend analysis revealed a significant decreasing trend during the post‐BMP period for FC concentrations at the watershed outlet, but not at the subwatershed level. Implementation of BMPs also resulted in a significant reduction in the geometric mean of FS concentrations. FC concentrations in streamflow at the watershed outlet exceeded the Virginia primary standard 86 and 74 percent of the time during pre‐BMP and post‐BMP periods, respectively. Corresponding exceedances for the secondary standard were 50 and 41 percent. Violations decreased only slightly during the post‐BMP period. The findings of this study suggest that although BMP implementation can be expected to accomplish some improvement in water quality, BMP implementation alone may not ensure compliance with current water quality standards.  相似文献   
142.
During the 1940’s, aluminum smelting installations were increased in size to provide aluminum necessary for World War II. Increased evolution of fluorides made necessary the capture and treatment of pot gases. Following the application of water scrubbers, cyclones, and electrostatic precipitators, Alcoa Research Laboratories at New Kensington, Pa., discovered that small quantities of HF gas would react at low temperature with alumina. Following a series of design efforts, the Alcoa 398 Process was developed, incorporating a fluidizedbed reactor to contact pot gases with incoming feed alumina. Bag filters are used to separate entrained solid materials from pot gases. Ninety-five percent interception of pot gases is reported with 99% recovery of fluorides from gases treated. No significant effect is observed on purity of metal produced.

Installation costs are in the range of $>28-$37 per annual ton for new installations and about 50% more for conversion of old plants. These are somewhat less than the conventional electrostatic precipitators and water scrubbers at today’s prices. Direct operating costs for the Alcoa 398 Process range from $2.90 to $4.70/ton of aluminum and recover $8 worth of fluorine, giving a net credit. This contrasts with $3.93/ton of aluminum to operate existing precipitator scrubber combinations. The Alcoa 398 Process is being rapidly extended throughout the Alcoa system.  相似文献   
143.
This paper explores how social networks and bonds within and across organisations shape disaster operations and strategies. Local government disaster training exercises serve as a window through which to view these relations, and ‘social capital’ is used as an analytic for making sense of the human relations at the core of disaster management operations. These elements help to expose and substantiate the often intangible relations that compose the culture that exists, and that is shaped by preparations for disasters. The study reveals how this social capital has been generated through personal interactions, which are shared among disaster managers across different organisations and across ‘levels’ within those organisations. Recognition of these ‘group resources’ has significant implications for disaster management in which conducive social relations have become paramount. The paper concludes that socio‐cultural relations, as well as a people‐centred approach to preparations, appear to be effective means of readying for, and ultimately responding to, disasters.  相似文献   
144.
Knowing the depth zone of neutral buoyancy of divers is important because buoyancy can determine how animals manage their energy budget. In this study, we estimate the depth zone of neutral buoyancy of free-ranging cormorants for the first time, using time-depth recorders. We discovered that vertical ascent rates of 12 Crozet and 15 Kerguelen diving blue-eyed shags (respectively Phalacrocorax melanogenis and P. verrucosus) slowed down considerably at the 50–60 m depth zone. We suggest this was due to birds trying to reach the surface from that point upwards using reduced locomotor activity because the force of buoyancy becomes greater than the force of gravity at that depth. The results show a shift of this depth zone in relation to maximum targeted dive depth, suggesting cormorants may control buoyancy through respiratory air volume adjustment. Interestingly, 60 m is close to the maximum depth zone reached by these two species during dives lasting 4 min, their estimated behavioural aerobic dive limit. This suggests that the decision to swim deeper has a direct consequence on the energy budget, with time spent recovering at the surface (time thus lost to foraging) strongly increasing relative to the preceding time of submergence. Resources found in deeper waters must be of sufficient quantity or quality to justify crossing the frontier of physical neutral buoyancy.  相似文献   
145.
Detailed research by the Commodities Research Unit (CRU) reveals a wide variation in direct operating costs at copper smelters and refineries. The cost curve for smelters is almost a straight line, indicating that so far there has been no levelling of costs as there has been in the mining industry. Operating costs at smelters using reverberatory furnaces are well below costs at plants using modern technology, but this apparent paradox is shown to be a reflection of location. CRU argues that costs are an important determinant of smelter/refinery competitiveness, but that other factors such as location and tariffs are also significant. Operating margins world-wide show enormous variations, but companies' increasing interest in their processing operations, coupled with changes in tariffs, are predicted to lead to a much more competitive market.  相似文献   
146.
The Ukraine, which gained independence in 1991, faces serious problems related to environmental degradation. Environmental problems contribute to a deterioration in human health and a negative trend in population growth. Both form part of a raft of socio-economic problems encountered during the country's transition to a free market economy. The most serious problems are found in cities and areas near the Black and Azov Seas, the Dnipro river basin and in the Polissya region. This paper provides an overview of the situation. Social and managerial implications of environmental management are considered alongside associated environmental and human health problems in the country. It is concluded that a desired change in the mindset of policy makers and, indeed, the population at large, is required in parallel with legal and technocratic instruments, while real improvements can only be achieved through economic development, which can be facilitated by Western assistance.  相似文献   
147.
The Nitrate Sensitive Area (NSA) scheme and the more recent Nitrate Vulnerable Zone (NVZ) scheme are responses by the British Government to the growing demands of European legislation on water quality. Both are designed to check nitrate contamination from agriculture at source, with 'polluting' activities being changed or prohibited in areas forming the catchment of waters where the 1980 European Commission (EC) limit of 50 mg/l nitrate (N) is exceeded, or is likely to be exceeded. The NVZ scheme provides protection to surface and ground water,whereas the NSA scheme relates directly to the latter. Furthermore, action programmes to reduce nitrate pollution within NVZs are mandatory and uncompensated, whilst the more strict but voluntary measures of the NSA scheme are compensated. This paper sets out to critically analyse the NVZ scheme, with reference to the NSA scheme and further makes recommendations for an improved nitrate pollution land use control policy in relation to ground water protection. The study area is Minster NVZ on the Isle of Thanet in north east Kent.  相似文献   
148.
In 1968, excavations in the Climente II cave in the Iron Gates gorge of the River Danube in southwest Romania unearthed the skeleton of an adult male. The burial was assumed to be of Late Pleistocene age because of the presence of Late Upper Palaeolithic (LUP) artefacts in the cave. However, there was no strong supporting stratigraphic evidence, and the body position is reminiscent of Early Neolithic burial practice in the region. Here, we report the results of radiocarbon and stable isotope analyses of the Climente II skeleton, which show that the skeleton dates to the Bølling–Allerød Interstadial ~14,500 cal BP. This is several millennia older than any previously dated human remains from the Iron Gates region and confirms its status as the oldest known burial from Romania. The stable isotope results indicate a diet with an emphasis on aquatic resources, contrary to the commonly held view that the LUP inhabitants of the Iron Gates subsisted mainly by hunting large land mammals.  相似文献   
149.
Numerous outbreaks have been attributed to the consumption of raw or minimally processed leafy green vegetables contaminated with enteric viral pathogens. The aim of the present study was an integrated virological monitoring of the salad vegetables supply chain in Europe, from production, processing and point-of-sale. Samples were collected and analysed in Greece, Serbia and Poland, from ??general?? and ??ad hoc?? sampling points, which were perceived as critical points for virus contamination. General sampling points were identified through the analysis of background information questionnaires based on HACCP audit principles, and they were sampled during each sampling occasion where as-ad hoc sampling points were identified during food safety fact-finding visits and samples were only collected during the fact-finding visits. Human (hAdV) and porcine (pAdV) adenovirus, hepatitis A (HAV) and E (HEV) virus, norovirus GI and GII (NoV) and bovine polyomavirus (bPyV) were detected by means of real-time (RT-) PCR-based protocols. General samples were positive for hAdV, pAdV, HAV, HEV, NoV GI, NoV GII and bPyV at 20.09?% (134/667), 5.53?% (13/235), 1.32?% (4/304), 3.42?% (5/146), 2?% (6/299), 2.95?% (8/271) and 0.82?% (2/245), respectively. Ad hoc samples were positive for hAdV, pAdV, bPyV and NoV GI at 9?% (3/33), 9?% (2/22), 4.54?% (1/22) and 7.14?% (1/14), respectively. These results demonstrate the existence of viral contamination routes from human and animal sources to the salad vegetable supply chain and more specifically indicate the potential for public health risks due to the virus contamination of leafy green vegetables at primary production.  相似文献   
150.
Successful, state-dependent management, in which the goal of management is to maintain a system in a desired state, involves defining the boundaries between different states. Once these boundaries have been defined, managers require a strategic action plan with thresholds that initiate management interventions to either maintain or return the system to a desired state. This approach to management is widely used across diverse industries from agriculture, to medicine, to information technology, but it has only been adopted in conservation management relatively recently. Conservation practitioners have expressed a willingness to integrate this structured approach in their management systems, but they have also voiced concerns, including lack of a robust process for doing so. Given the widespread use of state-dependent management in other fields, we conducted an extensive review of the literature on threshold-based management to gain insight into how and where it is applied and identify potential lessons for conservation management. We identified 22 industries using 75 different methods for setting management thresholds in 843 studies. Methods spanned six broad approaches, including expert driven, statistical, predictive, optimization, experimental, and artificial intelligence methods. The objectives of each of these studies influenced the approaches used, including the methods for setting thresholds and selecting actions, and the number of thresholds set. The role of value judgments in setting thresholds was clear; studies across all industries frequently involved experts in setting thresholds, often accompanied by computational tools to simulate the consequences of proposed thresholds under different conditions. Of the 30 conservation studies examined, two-thirds used expert-driven methods, consistent with prior evidence that experience-based information often drives conservation management decisions. The methods we identified from other disciplines could help conservation decision makers set thresholds for management interventions in different contexts, linking monitoring to management actions and ensuring that conservation interventions are timely and effective.  相似文献   
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