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61.
The family of tiger beetles (Cicindelidae) is an appropriate indicator taxon for determining regional patterns of biodiversity because (1) its taxonomy is stabilized; (2) its biology and general life history are well understood, (3) individuals are readily observed and manipulated in the field, (4) the family occurs world-wide and in a broad range of habitat types; (5) each species tends to be specialized within a narrow habitat; (6) patterns of species richness are highly correlated with those of other vertebrate and invertebrate taxa; and (7) the taxon includes species of potential economic importance. Logistical advantages provide some of the strongest arguments for selecting tiger beetles as an appropriate indicator taxon. Species numbers of tiger beetles are relatively well known for 129 countries. Eight countries alone account for more than half the world total of 2028 known species. Species numbers are also indicated for eleven biogeographical zones of the world. For gridded squares across North America, the Indian subcontinent, and Australia, species richness of tiger beetles, birds, and butterflies shows significant positive correlations. However, tiger beetle species numbers can be reliably determined within fifty hours on a single site, compared to months or years for birds or butterflies, and the advantage of using tiger beetles in conservation biology is evident  相似文献   
62.
Occupational exposure to elevated concentrations of benzene is a known cause of leukemia in adults. Concentrations of benzene from motor vehicle exhaust could be elevated along highly trafficked streets. Several studies have reported significant associations between proximity to highly trafficked streets and the occurrence of childhood cancers and childhood leukemia. These associations may be due to chronic exposure to benzene or other carcinogenic components of vehicle exhaust from these nearby streets or to some other factor (e.g., noise, increased light exposure, or some unaccounted--for socioeconomic variable). We used data for homes studied in an earlier childhood cancer study conducted in Denver, CO, in the 1980s. No air pollution measurements were made in the original study. We identified the highest trafficked street near each study home and obtained the traffic density in 1979 and 1990. Traffic density was weighted for the distance from the street to the home using 3 different widths of Gaussian curves to approximate the decay of the emissions into the surrounding neighborhoods. The associations between the 750-ft-wide distance-weighted traffic density metrics and all childhood cancers and childhood leukemia are strongest in the highest traffic density category (> or = 20,000 vehicles per day [VPD]). The odds ratio is 5.90 (95% confidence interval [CI] 1.69-20.56) for all cancers and 8.28 (95% CI 2.09-32.80) for leukemia. The results are suggestive of an association between proximal high traffic streets with traffic counts > or = 20,000 VPD and childhood cancer, including leukemia.  相似文献   
63.
Abstract: Due to the structuring forces and large-scale physical processes that shape our biosphere, we often find that environmental and ecological data are either spatially or temporally—or both spatially and temporally—dependent. When these data are analyzed, statistical techniques and models are frequently applied that were developed for independent data. We describe some of the detrimental consequences, such as inefficient parameter estimators, biased hypothesis test results, and inaccurate predictions, of ignoring spatial and temporal data dependencies, and we cite an example of adverse statistical results occurring when spatial dependencies were disregarded. We also discuss and recommend available techniques used to detect and model spatial and temporal dependence, including variograms, covariograms, autocorrelation and partial autocorrelation plots, geostatistical techniques, Gaussian autoregressive models, K functions, and ARIMA models, in environmental and ecological research to avoid the aforementioned difficulties.  相似文献   
64.
65.
Leachability of printed wire boards containing leaded and lead-free solder   总被引:1,自引:0,他引:1  
Due to environmental concerns and regulatory initiatives, electronics manufacturers are replacing the tin/lead solder commonly used on printed wire boards (PWBs) with alternative solders. To determine the potential waste management impacts of the alternative solders versus the tin/lead solder, two leaching tests on PWBs manufactured with five alternative types of solder were performed: the toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP). These tests are commonly used in the US regulatory community to assess pollutant leachability in different disposal scenarios. The article discusses the application and limitations of these tests. The five types of solders investigated were 63Sn/37Pb, 99.3Sn/0.7Cu, 95.5Sn/4Ag/0.5 Cu, 96Sn/2.5Ag/1Bi/0.5Cu, and 42Sn/1Ag/57Bi. The leaching tests were conducted on four PWB sections, each with a unique configuration and solder density. The largest lead concentrations were observed from the PWBs containing Sn/Pb solder, with concentrations exceeding the hazardous waste toxicity characteristic (TC) in TCLP leachates. Silver, the other regulated element used in the solders, was rarely detected, with none of the samples exceeding the TC limit for silver. High copper concentrations were observed and were determined to result from the PWB itself, not from the copper-containing solders.  相似文献   
66.

Problem

Subway transit is a relatively safe mode of transportation, yet compared to all other forms of mass transit in the United States (U.S.), subways have the highest fatality rate. The aim of this paper is to characterize subway-related fatalities in order to identify opportunities for risk reduction.

Method

Medical examiner records for all New York City (NYC) subway-related deaths (1990-2003) were reviewed. Data were abstracted on decedents' demographics and autopsy findings, including laboratory findings.

Results

There were 668 subway-related fatalities, of these, 10 (1.5%) were homicides, 343 (51.3%) were determined to be suicides, and 315 (47.2%) were accidental. Although decedent characteristics varied between fatality categories, they were not particularly informative with regard to prevention.

Conclusion

Prevention strategies that focus on structural controls are likely to be most efficacious in improving the overall safety of the NYC subway systems.

Impact on industry

These findings suggest that structural rather than individual-level interventions would be most successful in preventing subway fatalities.  相似文献   
67.
Twelve road-deposited sediment samples were analyzed for platinum-group elements (PGEs) and Pb in the <63 microm fraction of an urban watershed in Hawaii. Three samples were further fractionated into five size classes, from 63-125 microm to 1000-2000 microm, and these were analyzed for PGEs and Pb. Concentrations in the <63 microm fraction reached 174 microg/kg (Pt), 101 microg/kg (Pd), 16 microg/kg (Rh), and 1.3 microg/kg (Ir). Enrichment ratios followed the sequence Rh>Pt=Pd>Ir. Iridium was geogenic in origin, while the remaining PGEs indicated significant anthropogenic contamination. Palladium, Pt and Rh concentrations and enrichment signals were consistent with PGE bivariate ratios and PGE partitioning in three-way catalysts. Size partitioning indicated that the <63 microm fraction had the lowest PGE concentrations and mass loading percentages. These data suggest that autocatalyst PGE flux estimates into the environment will be significantly underestimated if only a fine grain size fraction is analyzed.  相似文献   
68.
A growing awareness of the value of indigenous knowledge has prompted calls for its use within disaster risk reduction. The use of indigenous knowledge alongside scientific knowledge is increasingly advocated but there is as yet no clearly developed framework demonstrating how the two may be integrated to reduce community vulnerability to environmental hazards. This paper presents such a framework, using a participatory approach in which relevant indigenous and scientific knowledge may be integrated to reduce a community's vulnerability to environmental hazards. Focusing on small island developing states it presents an analysis of the need for such a framework alongside the difficulties of incorporating indigenous knowledge. This is followed by an explanation of the various processes within the framework, drawing on research completed in Papua New Guinea. This framework is an important first step in identifying how indigenous and scientific knowledge may be integrated to reduce community vulnerability to environmental hazards.  相似文献   
69.
The objective of this study was to determine the feasibility of using salivary biomarkers to assess chlorpyrifos exposure using data collected from laboratory controlled animal study, as well as from farmers in Thailand and Nicaragua who applied chlorpyrifos in the field. Time-matched saliva and arterial blood samples were collected from rats and adult agricultural workers, while spot saliva samples were collected from children. Specimen samples were analyzed for chlorpyrifos using a commercially available enzyme-linked immunosorbent assay. The results from both animal and farmer studies show that chlorpyrifos is excreted into saliva. Nevertheless, salivary excretion of chlorpyrifos seems to differ from other pesticides, as evidenced by the lack of correspondence of chlorpyrifos levels between saliva and plasma samples. The lower chlorpyrifos concentrations in saliva collected from rats, and from farmers and their children, may have resulted from the rapid hydrolysis of chlorpyrifos during the intracellular passive diffusion in the salivary gland. In conclusion, chlorpyrifos is excreted into saliva; however, the majority of chlorpyrifos that is excreted in saliva may have been metabolized due to base-dependent hydrolysis. Because of this finding, it was hypothesized that it would be ideal to measure its metabolite, 3,5,6-trichloropyridinol, in saliva as the biomarker for chlorpyrifos exposure.  相似文献   
70.
In the Baltic Sea, the broadly distributed brown alga Fucus vesiculosus coexists in sympatry over part of its range (south west Gulf of Bothnia) with the Baltic endemic F. radicans sp. nov, while further north in colder and lower-salinity areas of the Baltic F. radicans occurs alone (north west Gulf of Bothnia). F. radicans appears to have arisen via rapid speciation from F. vesiculosus within the recent history of the Baltic (ca. 7500 BP). Possible functional divergence between the two species was investigated by comparing stress-responsive gene expression in a common-garden experiment. The experiment used two allopatric populations of Fucus vesiculosus from the Skagerrak (North Sea) and Central Baltic, as well as F. radicans from the same Central Baltic site. The two species in sympatry displayed divergent heat shock responses, while F. vesiculosus populations from allopatric sites did not. F. radicans was more sensitive to heat shock at 25°C, either alone or together with high irradiance and desiccation, than Baltic or Skagerrak F. vesiculosus. The results indicate that rapid functional divergence in the inducible heat shock response has occurred between sympatric species on a timescale of thousands of years.  相似文献   
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