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311.
Dennis C. Cory Mark E. Evans Julie P. Leones James C. Wade 《Journal of the American Water Resources Association》1992,28(5):889-901
ABSTRACT: The elimination of groundwater overdraft was a key feature of the 1980 Arizona Groundwater Management Act. To achieve this goal, the Arizona Department of Water Resources identified several Active Management Areas and developed urban, industrial, and agricultural water conservation plans. This study examines the reductions in groundwater use through agricultural water conservation in the Phoenix Active Management Area (AMA). Linear programming models are developed to analyze changes in groundwater use and net returns to agriculture over a 38-year period, 1990 to 2025, for farming areas in the Phoenix AMA. Results indicate that the agricultural conservation program provides only modest groundwater savings under a wide range of scenarios. The low level of savings is partly due to the current economically efficient use of water. Other policy measures such as retiring agricultural land may be necessary if the Phoenix AMA is to meet its overdraft reduction goals; even if urban water conservation goals are met. 相似文献
312.
Summary The residential environments in British urban areas are divided between those dominated by public sector (local authority) housing and those properties which are owner-occupied. It is widely recognised that the environmental quality of local authority housing estates varies considerably. It may be expected, therefore, that the United Kingdom 1980 Housing Act, which encouraged the tenants of public sector housing to purchase the dwellings they rented from local authorities, would have a differential impact, according to the environmental quality of those estates. However, this relationship has not been previously explored. Most studies have related sales to a range of socio- economic variables. Whilst these may effectively indicate ability to buy they do not necessarily indicate willingness to buy. It is argued that the latter may be more closely related to factors such as the quality of the local environment. Findings from the North Tyneside area in northern England suggest that the spatial pattern of sales is more closely related to an index of environmental quality than one composed largely of socio-economic variables. Some of the implications of this finding for policy in relation to public sector housing are then discussed. It is suggested that if the ultimate objective of the Housing Act is to promote a larger private sector, then initially this may require a considerably larger public sector involvement in environmental improvement.Dr Michael Barke, is the senior author, Principal Lecturer in Geography and Acting Head of the Department of Environment at Newcastle upon Tyne Polytechnic. He has published a number of articles on aspects of urban change in North-East England. Ms Julie Rowlands is a graduate in Environmental Studies from the same Polytechnic and currently studying for professional qualifications in urban and regional planning in Perth, Western Australia. 相似文献
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The potential application of enhanced in situ bioremediation (EISB) for treatment of a plume containing high concentrations of 1,2‐dichloroethane (1,2‐DCA), as well as lower concentrations of other chlorinated ethanes, chlorinated methanes, and chlorinated ethenes was evaluated through the implementation of four field trials. The field trials confirmed that EISB is an effective technology for treating multiple contaminants, with estimated mass removal rates on the order of several kilograms per day and groundwater concentration reductions nearing 100 percent of the initial concentrations. The field trials also demonstrated that engineering controls could be effectively used to overcome potential inhibitions related to high concentrations of 1,2‐DCA. © 2008 Wiley Periodicals, Inc. 相似文献
317.
The field of fetal therapy has so far escaped from formal accreditation and quality control. Despite that, current published evidence shows that outcomes of interventions in younger fetal therapy centers are similar to what is achieved in more experienced centers and outcomes of interventions have improved over time. The question however remains what is not being published and what should be the standard of care, given the lack of level 1 evidence from randomized controlled trials for many interventions. Formal collaborative networks such as NAFTnet and others allow for anonymized benchmarking of center outcomes, without publicly shaming (and financially punishing) underperforming centers. Large registries also allow for tracking of rare complications and may result in improved patient outcomes over time. Core outcome sets, which could serve as a basis for outcome reporting, are available for some conditions, but certainly not for all, resulting in communication difficulties between centers. Formal accreditation, quality control, and outcome reporting are hard to implement, expensive, and may result in decreasing access to care by pushing smaller centers out of the market. Despite the existing difficulties, international societies have committed to quality improvement, and fetal therapy programs are strongly recommended to participate in voluntary outcome tracking. 相似文献
318.
Julie K. Desjardins Kelly A. Stiver John L. Fitzpatrick Nicole Milligan Glen J. Van Der Kraak Sigal Balshine 《Behavioral ecology and sociobiology》2008,62(5):785-794
Among taxonomically widespread cooperatively breeding vertebrates, those with non-breeding helpers-at-the-nest provide an
excellent opportunity to understand the proximate mechanisms underlying care and allocare. In this study, we examined androgen
levels in relation to care behavior in a cooperatively breeding cichlid fish, Neolamprologus pulcher, from Lake Tanganyika. We concentrated on androgens, as these hormones have been linked to the defense behavior, and the
defense of young is a common form of parental care in fishes. N. pulcher dominant female breeders performed the most care and also displayed the highest levels of plasma testosterone (T) compared
with other individuals within the social group. We also found that dominant male breeders provided a similar amount of care
as did the subordinate helpers, but breeding males had the highest levels of 11-ketotestosterone (11KT), an important androgen
in fish. Breeders had higher levels of both androgens (T and 11KT) compared to helpers. There was a weak but significant positive correlation between T levels and the frequency of
care regardless of sex and status. Our results suggest that androgens may promote defense of young and are in contrast to
the commonly reported trade-off between androgen and parental care. 相似文献
319.
Julie B Kellner Irene Tetreault Steven D Gaines Roger M Nisbet 《Ecological applications》2007,17(4):1039-1054
Throughout the world "fishing the line" is a frequent harvesting tactic in communities where no-take marine reserves are designated. This practice of concentrating fishing effort at the boundary of a marine reserve is predicated upon the principle of spillover, the net export of stock from the marine reserve to the surrounding unprotected waters. We explore the consequences and optimality of fishing the line using a spatially explicit theoretical model. We show that fishing the line: (1) is part of the optimal effort distribution near no-take marine reserves with mobile species regardless of the cooperation level among harvesters; (2) has a significant impact on the spatial patterns of catch per unit effort (CPUE) and fish density both within and outside of the reserve; and (3) can enhance total population size and catch simultaneously under a limited set of conditions for overexploited populations. Additionally, we explore the consequences of basing the spatial distribution of fishing effort for a multispecies fishery upon the optimality of the most mobile species that exhibits the greatest spillover. Our results show that the intensity of effort allocated to fishing the line should instead be based upon more intermediate rates of mobility within the targeted community. We conclude with a comparison between model predictions and empirical findings from a density gradient study of two important game fish in the vicinity of a no-take marine-life refuge on Santa Catalina Island, California (USA). These results reveal the need for empirical studies to account for harvester behavior and suggest that the implications of spatial discontinuities such as fishing the line should be incorporated into marine-reserve design. 相似文献
320.
This paper is about an Integrated Coastal Management Project on an island, Isle-aux-Coudres, located in the St-Lawrence Estuary (Québec, Canada). It is based on data collected from 2003 to 2007 on the participatory aspects of the project such as: types of stakeholders, relationships between stakeholders, time dedicated to dialogue, consensus versus negotiation, and outcomes. We analyze the way concerns evolved into actions and the relationship between dialogue and actions during the project. We conclude that the difficulty is to join together the differences around various stakes, without forcing the consensus, or negating problems and conflicts. 相似文献