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431.
432.
Predicting Extinction Vulnerability in Skates 总被引:10,自引:0,他引:10
433.
Nicholas P. Lovrich John C. Pierce Taketsugu Tsurutani Takematsu Abe 《Journal of the American Water Resources Association》1986,22(2):229-236
ABSTRACT: This study examines the extent to which knowledge deficits pose a significant barrier to public support for nonpoint pollution management strategies. Such barriers would obtain if all of the following conditions are present: (1) many in the public lack knowledge relevant to those strategies; (2) variations in knowledge are linked only to relatively unchanging personal attributes; and (3) individuals with more knowledge are more likely to support the implementation of management strategies. Each of these conditions is subjected to empirical analysis in this study. The findings reported here derive from a survey of citizens in Spokane, Washington, the site of a major 208 Water Quality Management Program study. The results of the survey indicate that: portions of the public have enough knowledge to evaluate technically based management strategies; sources of public knowledge are sufficiently elastic that both policy area concern and policy relevant knowledge can be elevated in the short run; and both knowledge levels and general attitudes are related to the public's specific water policy preferences. The study concludes that the apparent lack of knowledge among the public is not necessarily a significant barrier to policy implementation, and that support for implementation may be generated through both knowledge enhancement and the tapping of existing political orientations through the placement of emphasis upon the seriousness of water resource problems. 相似文献
434.
Richard L. Shell Nicholas A. Damachi 《Journal of the American Water Resources Association》1985,21(2):323-330
To provide an overview of water utility information systems and the extent of computer use, a direct mail survey of all water utilities serving populations of 2,000 or more in the tri-state area - Ohio, Indiana, and Kentucky - was conducted. The following was determined: 1) utility profile information, e.g., public/private ownership, age, number of accounts, etc.; 2) an assessment of the degree of computerization presently in place to perform various functions; and 3) an assessment of any plans that the utilities may have for future computerization. To analyze the data, an index of computerization was defined as the number of departments or major activity areas of each utility that presently have some computerization. The relationship between the degree of computerization (measured by this index) and a utility's profile in terms of population served, annual revenue generated, and the number of customer accounts is discussed for each state in the survey. Discriminant analysis revealed strong significant differences between utilities that plan to use computers and those that do not. The differences were identified by the authors. Survey results revealed a rather limited use of computers in the tri-state area. Enormous potential exists in small and medium sized utilities for computerization to improve operational efficiency. 相似文献
435.
Melaleuca quinquenervia, is expanding rapidly throughout seasonally wet areas of southern Florida (USA), including the littoral zone of Lake Okeechobee.
Natural resource managers are concerned that a lower lake level regulation schedule under consideration for Lake Okeechobee,
while potentially beneficial to overall ecosystem health, might increase the rate of Melaleuca expansion. To investigate this possibility, Melaleuca saplings (harvested from the littoral zone) and 7-week-old seedlings (grown from harvested seeds) were subjected to various
hydroperiod treatments in replicated mesocosms. Hydroperiod treatments were selected based on a simulation of historical water
level variations. Saplings grew taller under longer hydroperiods with fluctuating water levels, including periods of submersion.
Time since germination affected the response of seedlings to inundation. Submersed 7-week-old seedlings grew slower and had
less biomass than submersed 12-week-old seedlings, yet mortality was low at both ages. Melaleuca's plasticity allows it to adapt to hypoxic, aquatic conditions by means of aquatic heterophylly and adventitious roots. Algae
and drought also increased mortality. Based on faster growth of Melaleuca under longer hydroperiods and its adaptability to seasonal flooding, a lower lake regulation schedule may not stimulate its
expansion. Therefore, water levels should not be manipulated only to control Melaleuca. Control of Melaleuca should continue using current practices such as manual removal or chemical treatment. 相似文献
436.
Particulate matter emissions and gaseous air toxic pollutants from commercial meat cooking operations 总被引:1,自引:0,他引:1
Nicholas Gysel William A.Welch Chia-Li Chen Poornima Dixit David R.Cocker Ⅲ Georgios Karavalakis 《环境科学学报(英文版)》2018,30(3):162-170
This study assessed the effectiveness of three novel control technologies for particulate matter (PM) and volatile organic compound (VOC) removal from commercial meat cooking operations. All experiments were conducted using standardized procedures at University of California, Riverside''s commercial test cooking facility. PM mass emissions collected using South Coast Air Quality Management District (SCAQMD) Method 5.1, as well as a dilution tunnel-based PM method showed statistically significantly reductions for each control technology when compared to baseline testing (i.e., without a catalyst). Overall, particle number emissions decreased with the use of control technologies, with the exception of control technology 2 (CT2), which is a grease removal technology based on boundary layer momentum transfer (BLMT) theory. Particle size distributions were unimodal with CT2 resulting in higher particle number populations at lower particle diameters. Organic carbon was the dominant PM component (> 99%) for all experiments. Formaldehyde and acetaldehyde were the most abundant carbonyl compounds and showed reductions with the application of the control technologies. Some reductions in mono-aromatic VOCs were also observed with CT2 and the electrostatic precipitator (ESP) CT3 compared to the baseline testing. 相似文献
437.
James J. Foster Shelby E. Temple Martin J. How Ilse M. Daly Camilla R. Sharkey David Wilby Nicholas W. Roberts 《Die Naturwissenschaften》2018,105(3-4):27
In recent years, the study of polarisation vision in animals has seen numerous breakthroughs, not just in terms of what is known about the function of this sensory ability, but also in the experimental methods by which polarisation can be controlled, presented and measured. Once thought to be limited to only a few animal species, polarisation sensitivity is now known to be widespread across many taxonomic groups, and advances in experimental techniques are, in part, responsible for these discoveries. Nevertheless, its study remains challenging, perhaps because of our own poor sensitivity to the polarisation of light, but equally as a result of the slow spread of new practices and methodological innovations within the field. In this review, we introduce the most important steps in designing and calibrating polarised stimuli, within the broader context of areas of current research and the applications of new techniques to key questions. Our aim is to provide a constructive guide to help researchers, particularly those with no background in the physics of polarisation, to design robust experiments that are free from confounding factors. 相似文献
438.
A Hydrological Model for Predicting the Effects of Dams on the Shoreline Vegetation of Lakes and Reservoirs 总被引:4,自引:0,他引:4
/ The species richness of shoreline vegetation of unregulated lakes in Nova Scotia, Canada, is known to increase as a function of catchment area, a topographic variable governing water level fluctuations. Predictions based on catchment area however, fail to account for richness patterns at the margins of lakes enlarged by dams. Here, we compare the vegetation and hydrological regimes of regulated and unregulated systems. Hydrological regimes of regulated systems deviated from natural systems of similar catchment area by being either hypovariable or hypervariable for both within-year and among-year fluctuations in water level. Plant communities of dammed systems were less diverse, contained more exotic species, and were, with one exception, devoid of rare shoreline herbs. Data from "recovering," or previously dammed systems indicated that shoreline communities can be restored upon return of the appropriate hydrological regime. Using observed within-year and among-year water level fluctuation data, we propose a general model for the maintenance or restoration of diverse herbaceous wetlands on shorelines of temperate lakes or reservoirs. Managers can manipulate the within-year water level variation within prescribed limits (1-2 m), while ensuring that among-year variation (SD of summer levels) is less than 25% of within-year variation. This preliminary model is based on data from low-fertility, temperate lakes in river systems. To calibrate the model, plant community data from other regions are needed, as are long-term water-level data for unregulated lakes, data which are essential but largely lacking in many areas.KEY WORDS: Catchment area; Regulated lakes; Shoreline restoration; Rare plants; Exotic plants; Diversity 相似文献
439.
440.
Nicholas Imparato 《Journal of Cleaner Production》2010,18(5):462-470
Human rights abuses, environmental predations and governance failures plague artisanal gold mining in Tanzania. Gold's exchange value and the illegality of most artisanal gold product challenge the traditional fair trade model, a potential solution. Additionally, memories of the government's earlier failed effort to serve as a sole purchaser of artisanal gold undercut enthusiasm for statist interventions. This paper presents an alternative: a public–private partnership (PPP) that would engage one or more private banks, an agency within the Ministry of Energy and Minerals and NGOs or international initiatives specifically aimed at improving conditions for artisanal mine operators. The concept of transformational exchange, wherein a set of business transactions substantially affects societal expectations, modifies behavior and promotes sustainable mechanisms, frames the proposal. 相似文献