ABSTRACT: There is increasing interest in using watershed councils to provide information to public natural resource managers, particularly in the western states. Watershed councils are composed of interested governmental and nongovernmental stakeholders that form to collaboratively manage water and other natural resources at the scale of a watershed. This research is the first step in a multi-step policy analysis designed to answer the question of whether watershed councils are an improvement over traditional methods of public involvement in natural resource management. This paper outlines why watershed councils form and discusses their structure and operation. There is considerable variability in terms of watershed councils' goals, their effectiveness, stakeholder composition, their involvement in the “real” decision-making process, types of participation that are allowed, leadership, financing, decision-making procedures, efficiency, and temporal scale. These structural components are presented as a framework that can be used by researchers to develop criteria to evaluate watershed councils. 相似文献
Accumulation of physical activity during daily living is a current public health target that is influenced by the layout of the built environment. This study reports how the layout of the environment may influence responsiveness to an intervention. Pedestrian choices between stairs and the adjacent escalators were monitored for 7 weeks in a train station (Birmingham, UK). After a 3.5 week baseline period, a stair riser banner intervention to increase stair climbing was installed on two staircases adjacent to escalators and monitoring continued for a further 3.5 weeks. Logistic regression analyses revealed that the visibility of the intervention, defined as the area of visibility in the horizontal plane opposite to the direction of travel (termed the isovist) had a major effect on success of the intervention. Only the largest isovist produced an increase in stair climbing. Additionally, stair climbing was more common during the morning rush hour and at higher levels of pedestrian traffic volume. The layout of the intervention site can influence responsiveness to point-of-choice interventions. Changes to the design of train stations may maximize the choice of the stairs at the expense of the escalator by pedestrians leaving the station. 相似文献
We studied Ovenbirds ( Seiurus aurocapillus ) in northern New Hampshire during 1992 and 1993 to determine whether edge-related changes in habitat use and reproductive success reported in fragmented landscapes exist in predominantly forested landscapes. Six study plots were placed adjacent to four recent clearcuts (2.1–5 ha) and extended 400 m into the forest interior. Nests, territories, and territorial males obtaining mates were equally distributed in edge (0–200 m) and interior (201–400 m) areas. Nest survival was higher in the forest interior in 1992 and for 1992 and 1993 combined. The proportion of pairs fledging ≥ 1 young, fledgling weight, and fledgling wing-chord did not differ between edge and interior in either year. Number of young fledged per pair was slightly lower in edge areas, but these differences were not significant. We conclude that clearcutting in extensively forested landscapes can affect Ovenbird reproductive success. Nevertheless, the effect on Ovenbird populations is moderated by the abundance of mature forest cover in the region and by the tendency of Ovenbirds to renest after initial nest failure. 相似文献
The models available for simulating phosphorus dynamics and trophic state in impoundments vary widely. The simpler empirically derived phosphorus models tend to be appropriate for long-term, steady or near steady state analyses. The more complex ecosystem models, because of computational expense and the importance of input parameter uncertainty, are impractical for very long-term simulation and most applicable for time-variable water quality simulations generally of short to intermediate time frames. An improved model for time variable, long-term simulation of trophic state in reservoirs with fluctuating inflow and outflow rates and volume is needed. Such a model is developed in this paper representing the phosphorus cycle in two-layer (i.e., epilimnion and hypolimnion) reservoirs. The model is designed to simulate seasonally varying reservoir water quality and eutrophication potential by using the phosphorus state variable as the water quality indicator. Long-term simulations with fluctuating volumes and variable influent and effluent flow rates are feasible and practical. The model utility is demonstrated through application to a pumped storage reservoir characteristic of these conditions. 相似文献
Summary The orientation sounds of many bats, almost certainly belonging to the genus Tadarida, were recorded at altitudes of 100 to 300 m above the ground by means of an ultrasonic radio microphone. Both in North Queensland, Australia, and in southern Utah and Nevada, USA, bats were often more numerous at 200 to 300 m than near the ground. Rapid increases in pulse repetition rate often indicated that these bats were actively hunting flying insects. The absence of clutter at high altitudes may significantly facilitate the detection and capture of insect prey. 相似文献
This paper compares the relative efficiencies of pollution taxes, pollution standards, and the auctioning of pollution rights when the marginal damage function or marginal control cost are subject to uncertainty. In the first case, we find that all instruments yield the same expected social surplus. In the latter case, the choice of the optimal instrument depends, in general, on the relative elasticities of the marginal damage and marginal expected cost functions, on the way in which uncertainty enters the model, and on the distribution of the error term. Policy conclusions are derived. 相似文献
The ability to monitor hydrogen peroxide (H2O2) in aqueous smoke extracts will advance our understanding of the relationship between cigarette smoke-induced oxidative stress, inflammation, and disease and help elucidate the pathways by which the various smoke constituents exert their pathogenic effects. We have demonstrated, for the first time, the measurement of H2O2 production from cigarette smoke without prior separation of the sample. Cigarettes were tested on a commercial smoking machine, such that the whole smoke or gas vapor phase was bubbled through phosphate buffered saline solution at pH 7.4. Aliquots of these solutions were analyzed using an Amplex Red/horseradish peroxidase fluorimetric assay that required only a 2 minute incubation time, facilitating the rapid, facile collection of data. Catalase was used to demonstrate the selectivity and specificity of the assay for H2O2 in the complex smoke matrix. We measured approximately 7-8 microM H2O2 from two reference cigarettes (i.e., 1R4F and 2R4F). We also observed 9x more H2O2 from whole smoke bubbled samples compared to the gas vapor phase, indicating that the major constituent(s) responsible for H2O2 formation reside in the particulate phase of cigarette smoke. Aqueous solutions of hydroquinone and catechol, both of which are particulate phase constituents of cigarette smoke, generated no H2O2 even though they are free radical precursors involved in the production of reactive oxygen species in the smoke matrix. 相似文献
ABSTRACT: The purpose of this paper is to describe a land use and environmental planning model. Map overlays were used for analyzing and aggregating economic, social, and environmental data. Various land use categories were evaluated using a numerical scoring system. These scores were then used to assist in the development of land use regulations in a coastal county in South Carolina. 相似文献
Objective: Statistics indicate that employees commuting or traveling as part of their work are overrepresented in workplace injury and death. Despite this, many organizations are unaware of the factors within their organizations that are likely to influence potential reductions in work-related road traffic injury.
Methods: This article presents a multilevel conceptual framework that identifies health investment as the central feature in reducing work-related road traffic injury. Within this framework, we explore factors operating at the individual driver, workgroup supervisor, and organizational senior management levels that create a mutually reinforcing system of safety.
Results: The health investment framework identifies key factors at the senior manager, supervisor, and driver levels to cultivating a safe working environment. These factors are high-performance workplace systems, leader–member exchange and autonomy, trust and empowerment, respectively. The framework demonstrates the important interactions between these factors and how they create a self-sustaining organizational safety system.
Conclusions: The framework aims to provide insight into the future development of interventions that are strategically aligned with the organization and target elements that facilitate and enhance driver safety and ultimately reduce work-related road traffic injury and death. 相似文献