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131.
Yamashita N Tanabe S Ludwig JP Kurita H Ludwig ME Tatsukawa R 《Environmental pollution (Barking, Essex : 1987)》1993,79(2):163-173
Persistent organochlorine contaminants including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were determined in eggs with normal and deformed embryos collected in 1988 from different colonies during an epizootiological survey of double-crested cormorants (Phalacrocorax auritus) and Caspian terns (Hydroprogne caspia) from the upper Great Lakes. PCBs and p,p'-DDE were found in the highest concentrations in eggs of both species. The residue pattern of PCB isomers and chlordane compounds suggested that double-crested cormorants have greater metabolic capacity to degrade contaminants than Caspian terns. According to the toxicity evaluation using the 2,3,7,8-TCDD equivalents (TEQs) approach, non-ortho coplanar PCBs contributed much more toxicity than PCDDs and PCDFs. Total TEQ of dioxin-like compounds was likely associated with occurrence of live-deformed embryos in double-crested cormorants eggs. The toxic effects of these contaminants were also estimated in Caspian tern eggs, where elevated levels of coplanar PCBs, PCDDs and PCDFs were observed in concordance with increased rate of anomalies in eggs during a breeding season in the Great Lakes. 相似文献
132.
133.
Bergmann Von Ludwig 《Die Naturwissenschaften》1964,51(14):325-332
134.
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Assigning money amounts to represent intrinsic value of precious eco-systems in developing countries
Harvey F. Ludwig 《The Environmentalist》2006,26(3):143-145
Conclusion The need is urgent, if the ongoing rapid degradation of the remaining precious eco-systems of the developing countries are
to be put under control while there is still time, for developing a procedure by which the real world intrinsic meaningfulness
to people of precious eco-systems is recognized by assigning them monetary values to be considered in benefit/cost analyses.
The procedures recommended by the U.S. Corps of Engineers and Resources of the Future for use in the USA seem to be much too
complex for application in developing countries in the foreseeable future. Rather a very pragmatic approach is recommended
based on actual experience in money outlays for such protection in USA projects, with the amounts modified to suit developing
country conditions. Hopefully the IAAs (Multilateral Development Banks, Bilaterials, U.N. Agencies) will carry out the recommended
R&D studies to produce a prescribed methodology recognized by economic, environmental, and political decision makers of both
the IAAs and the DCs to be appropriate for use in planning and evaluating DC projects. 相似文献
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139.
Markus Neuha¨user Dirk Seidel Ludwig A. Hothorn Wolfgang Urfer 《Environmental and Ecological Statistics》2000,7(1):43-56
In most real data situations in the one-way design both the underlying distribution and the shape of the dose-response curve are a priori unknown. The power of a trend test strongly depends on both. However, tests which are routinely used to analyze toxicological assays must be robust. We use nonparametric tests with different scores—powerful for different distributions—and different contrasts—powerful for different shapes—and use the maximum of all test statistics as a new test statistic. Simulation results indicate that this maximum test, which is a nonparametric multiple contrast test, stabilizes the power for various shapes and distributions. The investigated tests are applied to the data of a toxicological assay. 相似文献
140.
F. L. Ludwig Elmer Robinson 《Journal of the Air & Waste Management Association (1995)》2013,63(3):102-105
It is shown how the Goetz Aerosol Spectrometer can be used to determine the particle size distribution of a specific component of a mixed atmospheric aerosol. The method requires no micrographic counting, but does require that sensitive quantitative chemical analysis methods be available for the compounds of interest. The accuracy of the method and the sensitivity limitations are briefly discussed. 相似文献