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991.
Land reclamation techniques that incorporate habitat features for herptofaunal wildlife have received little attention. We
assessed the suitability of a wetland, constructed for the treatment of mine-water drainage, for supporting herptofaunal wildlife
from 1988 through 1990 using diurnal and nocturnal surveys. Natural wetlands within the surrounding watershed were also monitored
for comparison. The treatment wetland supported the greatest abundance and species richness of herptofauna among the sites
surveyed. Abundance was a function of the frog density, particularly green frogs (Rana clamitans) and pickerel frogs (R. palustris), while species richness was due to the number of snake species found. The rich mix of snake species present at the treatment
wetland was believed due to a combination of an abundant frog prey base and an amply supply of den sites in rock debris left
behind from earlier surface-mining activities. Nocturnal surveys of breeding male frogs demonstrated highest breeding activity
at the treatment wetland, particularly for spring peepers (Hyla crucifer). Whole-body assays of green frog and bullfrog (R. catesbeiana) tissues showed no differences among sites in uptake of iron, aluminum, and zinc; managanese levels in samples from the treatment
wetland were significantly lower than those from natural wetlands. These results suggest that wetlands established for water
quality improvement can provide habitat for reptiles and amphibians, with the species composition dependent on the construction
design, the proximity to source populations, and the degree of acidity and heavy-metal concentrations in drainage waters. 相似文献
992.
993.
A field experiment investigated factors expected to influence yielding by motorists to a pedestrian waiting to cross a city street. Subjects consisted of 604 motorists who passed through two marked crosswalks. Motorists were significantly more likely to stop for a disabled pedestrian using a cane than a non-disabled pedestrian without a cane. This study also evaluated the impact of a ‘fatality sign’ erected before one of the crossings. While the fatality sign by itself had no significant effect on motorists yielding, there was a strong interactive effect of the sign and the disability manipulation. Thus, the greatest levels of motorists yielding occurred for subjects who were exposed to the fatality sign and the disabled pedestrian. In contrast, the lowest levels of yielding occurred at the fatality-marked crossing for a non-disabled pedestrian. 相似文献
994.
Seok-Ku Ko Darrell G. Fontane John W. Labadie 《Journal of the American Water Resources Association》1992,28(1):111-127
ABSTRACT: Development of optimal operational policies for large-scale reservoir systems is often complicated by a multiplicity of conflicting project uses and purposes. A wide range of multiobjective optimization methods are available for appraising tradeoffs between conificting objectives. The purpose of this study is to provide guidance as to those methods which are best suited to dealing with the challenging large-scale, nonlinear, dynamic, and stochastic characteristics of multireservoir system operations. As a case study, the selected methodologies are applied to the Han River Reservoir System in Korea for four principal project objectives: water supply and low flow augmentation; annual hydropower production, reliable energy generation, and minimization of risk of violating firm water supply requirements. Additional objectives such as flood control are also considered, but are imposed as fixed constraints. 相似文献
995.
John Houlahan W. Andrew. Marcus Adel Shirmohammadi 《Journal of the American Water Resources Association》1992,28(3):553-567
ABSTRACT: This paper presents the results of an investigation of the effects of the Maryland Critical Area Act on generation of non-point source loads of phosphorus, nitrogen, and sediment to the Rhode River estuary. The Simple Method model, the Marcus and Kearney regression model, and the CREAMS model were used to estimate annual loads under: (1) present conditions, (2) maximum land use development allowable under the Act, and (3) two sets of future land use conditions that might occur if the Act were not in place. Results indicate that the Critical Area Act can reduce the present generation of nonpoint nutrient and sediment loadings 20–30 percent from the regulated area. These reductions can occur while preserving agricultural lands and allowing limited residential and urban development. The decrease in nutrient loadings is primarily dependent upon implementation and enforcement of agricultural best management practices (BMPs). The BMPs could reduce present agricultural nutrient loadings by 90 percent to a level comparable to loadings from residential areas. The estimated effectiveness of the Critical Area Act is even greater when compared to potential future nutrient loadings if development in the area remains unregulated. Unrestricted residential and urban development could increase nutrient loadings by 200 percent to 1000 percent as compared to controlled development under Critical Area Act guidelines. The Critical Area Act primarily prevents these future increases by severely limiting woodland cutting, with lesser results obtained by requiring urban BMPs. 相似文献
996.
Scott D. Lindsey Robert W. Gunderson J. Paul. Riley 《Journal of the American Water Resources Association》1992,28(5):865-875
ABSTRACT: Many hydrologic models have input data requirements that are difficult to satisfy for all but a few well-instrumented, experimental watersheds. In this study, point soil moisture in a mountain watershed with various types of vegetative cover was modeled using a generalized regression model. Information on sur-ficial characteristics of the watershed was obtained by applying fuzzy set theory to a database consisting of only satellite and a digital elevation model (DEM). The fuzzy-c algorithm separated the watershed into distinguishable classes and provided regression coefficients for each ground pixel. The regression model used the coefficients to estimate distributed soil moisture over the entire watershed. A soil moisture accounting model was used to resolve temporal differences between measurements at prototypical measurement sites and validation sites. The results were reasonably accurate for all classes in the watershed. The spatial distribution of soil moisture estimates corresponded accurately with soil moisture measurements at validation sites on the watershed. It was concluded that use of the regression model to distribute soil moisture from a specified number of points can be combined with satellite and DEM information to provide a reasonable estimation of the spatial distribution of soil moisture for a watershed. 相似文献
997.
Two studies were designed to test hypotheses derived from Locke's (1969, 1976, 1984) model of job satisfaction. Consistent with the model, both studies found that perceived have-want discrepancy scores were powerful predictors of facet job satisfaction. In addition, facet importance tended to moderate this relationship in the manner predicted by Locke. Workers who viewed a job facet as having high importance were more satisfied with a small perceived have-want discrepancy and more dissatisfied with a large discrepancy than workers who viewed the facet as having low importance. Finally, as expected, facet importance failed to moderate the relationship between facet satisfaction and overall job satisfaction. This finding supports Locke's proposition that facet satisfaction scores are ‘implicitly weighted’ by facet importance. Implications and directions for future research are discussed. 相似文献
998.
Jurgen Garbrecht Lawrence W. Martz 《Journal of the American Water Resources Association》1993,29(6):909-916
ABSTRACT: An automated extraction of channel network and sub-watershed characteristics from digital elevation models (DEM) is performed by model DEDNM. This model can process DEM data of limited vertical resolution representing low relief terrain. Such representations often include ill-defined drainage boundaries and indeterminate flow paths. The application watershed is an 84 km2 low relief watershed in southwestern Oklahoma. The standard for validation is the network and subwatershed parameters defined by the blue line method on USGS 7.5–minute topographic maps. Evaluation of the generated and validation networks by visual comparisons shows a high degree of correlation. Comparison of selected network parameters (channel length, slope, drainage density, etc.) and of drainage network composition (bifurcation, length, slope, and area ratios) shows that, on the average, the generated parameters are within 5 percent of those derived from the validation network. The largest discrepancies were found for the channel slope values. The results of this application demonstrate that DEDNM effectively addresses network definition problems often encountered in low relief terrain and that it can generate accurate network and subwatershed parameters under those conditions. 相似文献
999.
In previous research on unemployment, conflicting evidence has been found for a ‘reverse causation interpretation’, indicating that prolonged unemployment is a consequence of psychological distress instead of the reverse. The present longitudinal study was conducted to test this reverse causation explanation. A second issue addressed in this study was whether getting a job or not depends more strongly on subjective or psychological factors than on objective factors (e.g. a person's biographical background, length of unemployment). Two independent samples were examined: Sample 1 (n = 635) consisted of school-leavers, and sample 2 (n = 467) consisted of subjects who had been unemployed for more than one year. Some support was found for the reverse causation explanation. In addition, more than objective factors, a strong job orientation and a problem focused coping style appeared to be a precursor of success in the labour market. Accordingly, getting a job seems to be primarily a function of one's own efforts. 相似文献
1000.