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681.
River basin computer simulation studies often do not properly include the complex legal and institutional factors governing water allocation. These factors include formal water rights and informal borrowing agreements among the basin water users. An attempt has been made in this study to show that such factors can be included. We also show that an optimal, integrated approach to reservoir operations in a river basin can do much to alleviate the burden of new demands placed on available water resources. The procurement of a firm water supply for a proposed coal fired power plant is analyzed as a case study. An efficient river basin simulation model is used to determine the viability of a scheme for providing an annual firm water supply to the plant, with consideration of the existing water storage and demands within the basin. Given the hydrologic sequence considered, the model results show that the proposed strategy is viable in that the required firm water supply can be realized without causing harm to decreed water users in the basin. However, integrated diversion and reservoir operations are required to assure a desirable uniform rate of delivery of reusable effluent to the power plant.  相似文献   
682.
683.
The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment.  相似文献   
684.
The pelagic crustacean Euphausia pacifica Hansen was sampled with a multiple-sample 1.0 m2 Tucker trawl and a multiple-sample 1.0 m2 vertical net in Dabob Bay, Washington on 17 dates between May 1985 and October 1987. Size (stage) structure and abundance of the population were determined for each date, while vertical distribution and diel migration were determined for 13 dates. Although internannual variability in both timing and magnitude of events occurred, consistent patterns were discernable. The population produced a large pulse of larvae (2 to 5 mm) in late spring of each year, apparently in response to the vernal phytoplankton bloom. Much lower abundances of larvae occurred during summer and autumn of each year, and larvae were completely absent during winter. Recruitment to the juvenile (6 to 9 mm) and adult (10 mm) stages was strongest during the summer, with abundances of these individuals peaking in summer and autumn. Individual growth rates, determined by modal progression analysis, were calculated for E. pacifica. Rates ranged from zero for some adult cohorts during the winter to 0.12 mm d-1 for larvae during spring. The latter are among the highest ever reported for this species in the field. The vertical distributions and diel vertical migrations (DVM) of E. pacifica varied seasonally and between size (stage) classes. At night, all size classes were distributed in the surface layer (upper 25 m) irrespective of season or year. During the day, the larger/older stages were always distributed at middepths (50 to 125 m). In contrast, the daytime distribution of the larvae was more variable, being concentrated at the surface during spring and early summer of 1985, and at increasing depths later in the summer and autumn of 1985 and again in spring of 1986. This resulted in invariant DVM in the juveniles and adults, but variable DVM in the larvae, the latter of which is hypothesized to be a response to variable abundances of zooplanktivorous fish.  相似文献   
685.
We synthesized nine studies that examined the influence of land use at different spatial scales in structuring biotic assemblages and stream channel characteristics in southeastern Minnesota streams. Recent studies have disagreed about the relative importance of catchment versus local characteristics in explaining variation in fish assemblages. Our synthesis indicates that both riparian- and catchment-scale land use explained significant variation in water quality, channel morphology, and fish distribution and density. Fish and macroinvertebrate assemblages can be positively affected by increasing the extent of perennial riparian and upland vegetation. Our synthesis is robust; more than 425 stream reaches were examined in an area that includes a portion of three ecoregions. Fishes ranged from coldwater to warmwater adapted. We suggest that efforts to rehabilitate stream system form and function over the long term should focus on increasing perennial vegetation in both riparian areas and uplands and on managing vegetation in large, contiguous blocks. Minnesota Cooperative Fish and Wildlife Research Unit is jointly sponsered by U.S. Geological Survey Biological Resources Division, the University of Minnesota, The Minnesota Department of Natural Resources, and the Wildlife Management Institute.  相似文献   
686.
What is the relationship between biotechnology employees’ beliefs about the moral outcomes of a controversial transgenic research project and their attitudes of acceptance towards the project? To answer this question, employees (n=466) of a New Zealand company, AgResearch Ltd., were surveyed regarding a project to create transgenic cattle containing a synthetic copy of the human myelin basic protein gene (hMBP). Although diversity existed amongst employees’ attitudes of acceptance, they were generally: in favor of the project, believed that it should be allowed to proceed to completion, and that it is acceptable to use transgenic cattle to produce medicines for humans. These three items were aggregated to form a project acceptance score. Scales were developed to measure respondents’ beliefs about the moral outcomes of the project for identified stakeholders in terms of the four principles of common morality (benefit, non-harm, justice, and autonomy). These data were statistically aggregated into an Ethical Valence Matrix for the project. The respondents’ project Ethical Valence Scores correlated significantly with their project acceptance scores (r=0.64, p<0.001), accounting for 41% of the variance in respondents’ acceptance attitudes. Of the four principles, non-harm had the strongest correlation with attitude to the project (r=0.59), followed by benefit and justice (both r=0.54), then autonomy (r=0.44). These results indicate that beliefs about the moral outcomes of a research project, in terms of the four principles approach, are strongly related to, and may be significant determinants of, attitudes to the research project. This suggests that, for employees of a biotechnology organization, ethical reasoning could be a central mechanism for the evaluation of the acceptability of a project. We propose that the Ethical Valence Matrix may be used as a tool to measure ethical attitudes towards controversial issues, providing a metric for comparison of perceived ethical consequences for multiple stakeholder groups and for the evaluation and comparison of the ethical consequences of competing alternative issues or projects. The tool could be used to measure both public and special interest groups’ ethical attitudes and results used for the development of socially responsible policy or by science organizations as a democratizing decision aid to selection amongst projects competing for scarce research funds.  相似文献   
687.
The manufacture and improper disposal of explosives has resulted in a significant amount of land requiring remediation. The compound 2,4,6-trinitrotoluene (TNT) is the most persistent and toxic of the explosive pollutants with current treatment methods being energy intensive and costly. Bacterial enzymes such as pentaerythritol tetranitrate reductase (PETNR) from Enterobacter cloacae PB2 have been found to have activity against TNT; however, microbes often lack the biomassnecessary for remediation applications. The PETNRgene (onr1) was transformed into tobacco plants in an attempt to combine the metabolic diversity of microbes with the sequestering properties of plants. The resulting transgenic plants were shown to have enhanced tolerance to TNT during germination and as seedlings. Phytoremediation applications with these plants may provide an alternative treatment of TNT contamination.  相似文献   
688.
689.
Beach erosion on Cinnamon Bay in the U.S. Virgin Islands results from storm waves in the North Atlantic. The net trend of erosion, however, is due to local environmental degradation. Reef die-back, initiated during the period of high sedimentation associated with 18th and 19th century sugar cane cropping, has reduced the rate of generation of new coral sands. Sand losses to deep water during periods of storm waves are not replenished. Engineering measures designed to check erosion at Cinnamon Bay have had little effect in this environment of low wave energies, but sand deficiency. The appropriate environmental focus for management of reef-beach systems is reef health and thus, water quality.  相似文献   
690.
Future technological developmentsconcerning food, agriculture, and theenvironment face a gulf of social legitimationfrom a skeptical public and media, in the wakeof the crises of BSE, GM food, and foot andmouth disease in the UK (House of Lords, 2000). Keyethical issues were ignored by the bioindustry,regulators, and the Government, leaving alegacy of distrust. The paper examinesagricultural biotechnology in terms of a socialcontract, whose conditions would have to be fulfilled togain acceptance of novel applications. Variouscurrent and future GM applications areevaluated against these conditions. Successwould depend critically on how far a sharedvision can be found with the public. Tore-establish trust, significant changes areidentified in the planning and pursuit ofbiotechnology.  相似文献   
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