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J C Hall L K Wilson R A Chapman 《Journal of environmental science and health. Part. B》1992,27(5):523-544
An indirect enzyme-linked immunosorbent assay (EIA) for metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamid e) detection in river water and soil was developed using serum obtained from rabbits immunized against the acid of metalaxyl ((N-(2,6-dimethylphenyl)-N-(methoxy-acetyl)-DL-alanine methyl ester) conjugated to bovine serum albumin. The assay had a linear working range from 1 to 50 ng/ml with a mean I50 value of 13.6 ng/ml and a lower detection limit of 2.0 ng/ml. Both the mean interwell and interassay coefficients of variation were less than 4% over the range of the standard curves for samples which had been prepared in phosphate buffered saline (PBS), river water, or soil extract. Assay cross-reactivity to the following four structurally related chloro-acetanilide pesticides were: propachlor (0%), metazachlor (0%), alachlor (23%), and metalaxyl (5,000%). Mean recoveries of metolachlor in spiked (2.0 to 32.0 ng/ml range) PBS, river water, and soil extract were 102%, 103%, and 110%, respectively. Soil samples were taken over a 56-d period from field plots treated with metolachlor and analyzed by GC and EIA. The correlation coefficient for comparison of the two methods was 0.96 with the slope of the linear regression line being 0.78. Furthermore, no statistical difference (P less than 0.05) was found between the dissipation curves of metolachlor derived from GC data versus EIA data. 相似文献
86.
The partial differential equation governing the movement of a decomposing pollutant undergoing 2-dimensional flow in a saturated aquifer is examined. The analytical solution of the equation is usually not possible, and use of mesh numerical integration techniques causes excessive numerical dispersion to arise from the advection term. We apply two asymmetrical upwind formulas to approximate the advection term. These markedly reduce numerical dispersion without requiring the use of coordinate systems obtained by conformal mapping. Flow within a right angle and flow toward a sink in an otherwise uniform field are analyzed to illustrate the methods. 相似文献
87.
Perceived Impacts of Ecotourism on Environmental Learning and Conservation: Turtle Watching as a Case Study 总被引:1,自引:0,他引:1
Clem?TisdellEmail author Clevo?Wilson 《Environment, Development and Sustainability》2005,7(3):291-302
Using a case study, involving turtle-based ecotourism, we explore the role of ecotourism in promoting environmental learning
and in sustaining conservation of nature. Mon Repos Conservation Park (an important marine turtle rookery involved in ecotourism)
in Queensland, Australia, was selected for this study and visitors were surveyed using a structured questionnaire. The reported
on-site experiences of respondents are analysed to identify important factors that alter their stated conservation attitudes
and behaviours. The impact of these factors (such as the amount of environmental education that respondents claimed they obtained,
sighting of sea turtles, nationality) is quantified using regression analyses. There has been little previous quantification
of such influences. The study reveals that a considerable amount of environmental knowledge is gained by visitors to Mon Repos.
The ecotourism experience, involving environmental education and seeing of turtles, was found to have positive and statistically
significant impacts on the visitors' stated desire and intended behaviour to protect sea turtles. The study reveals the importance
of learning and the interaction of tourists with wildlife as a contributor to their pro-conservation sentiments and actions.
It shows how ecotourism can support nature conservation.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
88.
J. G. Wilson 《Marine Biology》1976,37(4):371-376
The dispersion of Tellina tenuis da Costa in the laboratory was analysed by the Clark and Evans nearest-neighbour test and by the Kolmogorov-Smirnov one-sample test. The dispersion was random, with a slight tendency toward aggregation that was independent of density. In the field, the dispersion was analysed by the Clark and Evans nearest-neighbour test and by the X2 approximation to Fisher's coefficient of dispersion. The dispersion was again random, this time with a slight tendency toward spacing out that was independent of density. The tendency toward aggregation displayed in the laboratory was independent of the dispersion pattern shown at the start of the experiment, and also unaffected by the edge of the container. The apparent randomness suggests that T. tenuis is primarily a suspension feeder, but may be a deposit feeder under certain environmental conditions. 相似文献
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90.
Jellyfish aggregations and leatherback turtle foraging patterns in a temperate coastal environment 总被引:11,自引:0,他引:11
Leatherback turtles (Dermochelys coriacea) are obligate predators of gelatinous zooplankton. However, the spatial relationship between predator and prey remains poorly understood beyond sporadic and localized reports. To examine how jellyfish (Phylum Cnidaria: Orders Semaeostomeae and Rhizostomeae) might drive the broad-scale distribution of this wide ranging species, we employed aerial surveys to map jellyfish throughout a temperate coastal shelf area bordering the northeast Atlantic. Previously unknown, consistent aggregations of Rhizostoma octopus extending over tens of square kilometers were identified in distinct coastal "hotspots" during consecutive years (2003-2005). Examination of retrospective sightings data (>50 yr) suggested that 22.5% of leatherback distribution could be explained by these hotspots, with the inference that these coastal features may be sufficiently consistent in space and time to drive long-term foraging associations. 相似文献