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241.
Multiple regression models: a methodology for evaluating trihalomethane concentrations in drinking water from raw water characteristics 总被引:4,自引:0,他引:4
The presence of trihalomethanes (THMs) in drinking water has attracted the attention of both researchers and professionals, because of the harmful effects of these substances on human health. A multiple regression model was developed to estimate THM concentrations in finished drinking water, using data from the Menidi Treatment Plant of Athens. A number of routinely measured characteristics--including chlorine dose, chlorophyll a, temperature, pH and bromide--of raw water, were used to generate a reliable methodology for predicting both total THM and individual species concentrations. Seasonality effects were also considered during the analysis. In general, these models were found to give acceptable fits, estimating accurately lows and highs over the annual cycle. 相似文献
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Efficacy of extracting indices from large‐scale acoustic recordings to monitor biodiversity
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Rachel T. Buxton Mary Clapp Erik Meyer Erik Stabenau Lisa M Angeloni Kevin Crooks George Wittemyer 《Conservation biology》2018,32(5):1174-1184
Passive acoustic monitoring could be a powerful way to assess biodiversity across large spatial and temporal scales. However, extracting meaningful information from recordings can be prohibitively time consuming. Acoustic indices (i.e., a mathematical summary of acoustic energy) offer a relatively rapid method for processing acoustic data and are increasingly used to characterize biological communities. We examined the relationship between acoustic indices and the diversity and abundance of biological sounds in recordings. We reviewed the acoustic‐index literature and found that over 60 indices have been applied to a range of objectives with varying success. We used 36 of the most indicative indices to develop a predictive model of the diversity of animal sounds in recordings. Acoustic data were collected at 43 sites in temperate terrestrial and tropical marine habitats across the continental United States. For terrestrial recordings, random‐forest models with a suite of acoustic indices as covariates predicted Shannon diversity, richness, and total number of biological sounds with high accuracy (R2 ≥ 0.94, mean squared error [MSE] ≤170.2). Among the indices assessed, roughness, acoustic activity, and acoustic richness contributed most to the predictive ability of models. Performance of index models was negatively affected by insect, weather, and anthropogenic sounds. For marine recordings, random‐forest models poorly predicted Shannon diversity, richness, and total number of biological sounds (R2 ≤ 0.40, MSE ≥ 195). Our results suggest that using a combination of relevant acoustic indices in a flexible model can accurately predict the diversity of biological sounds in temperate terrestrial acoustic recordings. Thus, acoustic approaches could be an important contribution to biodiversity monitoring in some habitats. 相似文献
244.
Protected areas (PAs) are a frequently used conservation strategy, yet their socioeconomic impacts on local communities remain contentious. A shift toward increased participation by local communities in PA governance seeks to deliver benefits for human well‐being and biodiversity. Although participation is considered critical to the success of PAs, few researchers have investigated individuals’ decisions to participate and what this means for how local people experience the costs and benefits of conservation. We explored who participates in PA governance associations and why; the perceived benefits and costs to participation; and how costs and benefits are distributed within and between communities. Methods included 3 focus groups, 37 interviews, and 217 questionnaire surveys conducted in 3 communities and other stakeholders (e.g., employees of a nongovernmental organization and government officials) in PA governance in Madagascar. Our study design was grounded in the theory of planned behavior (TPB), the most commonly applied behavior model in social psychology. Participation in PA governance was limited by miscommunication and lack of knowledge about who could get involved and how. Respondents perceived limited benefits and high costs and uneven distribution of these within and between communities. Men, poorer households, and people in remote villages reported the highest costs. Our findings illustrate challenges related to comanagement of PAs: understanding the heterogeneous nature of communities; ensuring all households are represented in governance participation; understanding differences in the meaning of forest protection; and targeting interventions to reach households most in need to avoid elite capture. 相似文献
245.
As the limitations of site remedial technologies become more apparent and greater experience in their field implementation and effectiveness is gained, increased emphasis is placed on development of a structured technology selection process. Ideally, this selection process should yield the most cost-effective technology, which will accomplish cleanup goals in the shortest time frame. Although laboratory treatability studies comprise an essential component of this process, very little has been written about the methodology of designing, executing, and assessing the value of their results. This article presents practical considerations for environmental professionals who use treatability results in technology selection or others who execute such studies. 相似文献
246.
George Van Houtven Maureen L. Cropper 《Journal of Environmental Economics and Management》1996,30(3):348-368
Under certain environmental statutes the EPA is required to balance costs and benefits in setting standards, whereas under others this is prohibited. This paper examines EPA regulatory decisions made under three statues, two of which require balancing and one of which does not. Using discrete choice models, we find that costs and benefits are significant explanatory variables for all three sets of decisions. This suggests that balancing occurred in each case; however, the value (implicit in these decisions) of avoiding a cancer case varies widely. We also find that a 1987 court ruling effectively curtailed whatever balancing occurred under the statute that prohibited it. 相似文献
247.
George H. Nieswand Robert M. Hordon Theodore B. Shelton Budd B. Chavooshian Steven Blarr 《Journal of the American Water Resources Association》1990,26(6):959-966
ABSTRACT: Buffer strips are undisturbed, naturally vegetated zones around water supply reservoirs and their tributaries that are a recognized and integral aspect of watershed management. These strips can be very effective in protecting the quality of public potable water supply reservoirs by removing sediment and associated pollutants, reducing bank erosion, and displacing activities from the water's edge that represent potential sources of nonpoint source pollutant generation. As part of a comprehensive watershed management protect for the State of New Jersey, a parameter-based buffer strip model was developed for application to all watersheds above water supply intakes or reservoirs. Input requirements for the model include a combination of slope, width, and time of travel. The application of the model to a watershed in New Jersey with a recommended buffer strip width that ranges from 50 to 300 feet, depending upon a number of assumptions, results in from 6 to 13 percent of the watershed above the reservoir being occupied by the buffer. 相似文献
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Assessing the Vulnerability of Coastal Communities to Extreme Storms: The Case of Revere,MA., USA 总被引:6,自引:1,他引:6
Clark George E. Moser Susanne C. Ratick Samuel J. Dow Kirstin Meyer William B. Emani Srinivas Jin Weigen Kasperson Jeanne X. Kasperson Roger E. Schwarz Harry E. 《Mitigation and Adaptation Strategies for Global Change》1998,3(1):59-82
Climate change may affect the frequency, intensity, and geographic distribution of severe coastal storms. Concurrent sea-level
rise would raise the baseline of flooding during such events. Meanwhile, social vulnerability factors such as poverty and
disability hinder the ability to cope with storms and storm damage. While physical changes are likely to remain scientifically
uncertain into the foreseeable future, the ability to mitigate potential impacts from coastal flooding may be fostered by
better understanding the interplay of social and physical factors that produce human vulnerability. This study does so by
integrating the classic causal model of hazards with social, environmental, and spatial dynamics that lead to the differential
ability of people to cope with hazards. It uses Census data, factor analysis, data envelopment analysis, and floodplain maps
to understand the compound social and physical vulnerability of coastal residents in the city of Revere, MA, USA.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献