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Sheppard PR Speakman RJ Ridenour G Witten ML 《Environmental monitoring and assessment》2007,130(1-3):511-518
This paper describes the use of lichen chemistry to assess airborne tungsten and cobalt in Fallon, Nevada, where a cluster
of childhood leukemia has been on going since 1997. Lichens and their rock substrates were collected from Rattlesnake Hill
within Fallon as well as from four different rock outcrops located north, east, south, and west of Fallon and at least 20 km
away from the town center. In the lichens themselves, W and Co are significantly higher within Fallon than in the combined
control site outside of Fallon. In the rock substrates of the lichens, no differences exist in W and Co. The W and Co differences
in lichens cannot be attributed to substrate geochemistry. Fallon is distinctive in west central Nevada for high airborne
W and Co, and given its cluster of childhood leukemia, it stands to reason that additional biomedical research is in order
to test directly the leukogenicity of combined airborne W and Co. 相似文献
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Sheppard PR Speakman RJ Ridenour G Glascock MD Farris C Witten ML 《Environmental geochemistry and health》2007,29(5):405-412
Spatial patterns of tungsten and cobalt are described for surface dust of Fallon, Nevada, where a cluster of childhood leukemia
has been ongoing since 1997. In earlier research, airborne tungsten and cobalt was shown to be elevated in total suspended
particulates in Fallon. To fine-tune the spatial patterns of tungsten and cobalt deposition in Fallon, surface dust was collected
in a grid pattern within as well as outside of Fallon to establish background concentrations of metals. In surface dust, tungsten
and cobalt show sharp peaks (934 ppm and 98 ppm, respectively) within Fallon just north of highway 50 and west of highway
95. These two peaks overlap spatially, and given the grid pattern used for collecting surface dust, the source area of these
two airborne metals can be pinpointed to the vicinity of hard-metal industry located north of highway 50 and west of highway
95. Fallon is distinctive in west central Nevada because of high airborne tungsten and cobalt particulates, and given its
cluster of childhood leukemia, it stands to reason that additional biomedical research is in order to test directly the leukogenicity
of combined airborne tungsten and cobalt particulates. 相似文献
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Schaffner U Ridenour WM Wolf VC Bassett T Müller C Müller-Schärer H Sutherland S Lortie CJ Callaway RM 《Ecology》2011,92(4):829-835
One commonly accepted mechanism for biological invasions is that species, after introduction to a new region, leave behind their natural enemies and therefore increase in distribution and abundance. However, which enemies are escaped remains unclear. Escape from specialist invertebrate herbivores has been examined in detail, but despite the profound effects of generalist herbivores in natural communities their potential to control invasive species is poorly understood. We carried out parallel laboratory feeding bioassays with generalist invertebrate herbivores from the native (Europe) and from the introduced (North America) range using native and nonnative tetraploid populations of the invasive spotted knapweed, Centaurea stoebe. We found that the growth of North American generalist herbivores was far lower when feeding on C. stoebe than the growth of European generalists. In contrast, North American and European generalists grew equally well on European and North American tetraploid C. stoebe plants, lending no support for an evolutionary change in resistance of North American tetraploid C. stoebe populations against generalist herbivores. These results suggest that biogeographical differences in the response of generalist herbivores to novel plant species have the potential to affect plant invasions. 相似文献
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