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991.
Gerrit Schüürmann Klaus-Dieter Wenzel Ludwig Weißflog Klaus Wienhold Eckhard Müller 《Environmental Sciences Europe》1994,6(5):265-270
The spatial variation of the immission patterns of Cr, Fe, Pb and V in the region Leipzig-Halle is dicussed in terms of similarities as well as dissimilarities. The representation by isopleths enables the identification of areas with high and low air pollution. The immission patterns can be used as criteria to select areas suitable for in-field testing so that possible effects on fauna und flora and xenobiotic fluxes can be studied at representative sites. The comparison with literature data yields a first characterization of the ecotoxic potential of the heavy-metal immission for the region. By the principal component analysis a comparative evaluation of the spatial structure of all element contents is performed, which leads to conclusions about emission sources and the physicochemical behaviour of the elements. 相似文献
992.
In order to observe the metabolic response of two marine polychaetes, Arenicola marina L. and Nereis diversicolor Müller, at various times during low tide, the concentrations of adenine nucleotides, phosphagens, D- and L-alanine, succinate, acetate, propionate and lactate were measured. During 8h of exposure ATP does not change significantly in the body-wall musculature of the lug-worm A. marina, whereas ADP and AMP concentrations double the first hour of exposure. Correspondingly, the energy charge falls from 0.91 to about 0.84. The concentration of the phosphagen phosphotaurocyamine decreases by about 20% during the first 2 h and after 6 h only about 50% of the initial concentration was measured. During exposure, aspartate decreases by approximately 6 mol g-1 fresh weight within 6 h (from 23 to 17 mol g-1 fresh weight). During the first 4 h of exposure succinate concentration doubles and within the next 4 h it reaches values about 10-fold the initial value. The concentrations of acetate and propionate only increase during the last 2 h (6–8) of exposure. After several hours of exposure typical changes in the concentrations of all these metabolites could also be demonstrated in N. diversicolor. The concentrations of the two phosphagens phosphoglycocyamine and phosphocreatine and of aspartate decrease by about 25% during 9 h of exposure, on the other hand succinate and especially D-lactate accumulate. In both species, the partial anaerobic energy production during exposure does not have a lasting detrimental effect. After one high tide the worms have fully recovered. 相似文献
993.
A temnospondyl ilium from the uppermost Toutunhe Formation (Middle Jurassic, Callovian) of the southern Junggar Basin is described. Among the known temnospondyls it is very unusual in morphology because of its very long and slender shaft. It compares closely only to the ilium of one of the latest known trematosaurids from the Ladinian of southern Germany. The Toutunhe Formation has also yielded vertebrae and skull fragments of temnospondyls which belong to the brachyopid Gobiops from the Upper Jurassic of Mongolia. Brachyopoid ilia do not, however, display a morphology similar to that of the new specimen. It is therefore concluded that this specimen represents a second taxon of temnospondyl from the Toutunhe Formation, which probably represents the latest surviving trematosauroid. The Trematosauroidea, which was hitherto exclusively known from the Lower to early Upper Triassic, therefore joins the Brachyopoidea – and possibly the Capitosauroidea – as another group of temnospondyls which survived the end-Triassic mass extinction. 相似文献
994.
Determination of the aerobic biodegradability of polymeric material in aquatic batch tests 总被引:2,自引:0,他引:2
Results of an international ring-test of two laboratory methods are presented for investigating the biodegradability of organic polymeric test materials in aquatic test systems based on respirometry and the evolution of carbon dioxide. These methods are developed further from the well-known standardized biodegradation tests ISO 9408 (1999) and ISO 9439 (1999), which have been successfully used for many years. The most important improvements are the extension of the test period up to six months, the increase of the buffer capacity and nutrient supply of the inorganic medium, an optimization of the inoculation, and optionally, the possibility of a carbon balance. A ring test, organized by the International Biodeterioration Research Group (IBRG), was run using a poly(,-caprolactone)-starch blend and an aliphatic-aromatic co-polyester as test materials and a microcrystalline cellulose powder as a reference material. The test results and the experience gained by the participants showed that the methods are suitable and practicable. The test methods have been meanwhile established as standards ISO 14851 (1999) and ISO 14852 (1999). 相似文献
995.
Andreas Faludi 《Journal of Environmental Planning and Management》1989,32(1):55-65
This paper is based on one given by Professor Faludi at the Conference on Planning Theory at Torino, Italy in 1986. It answers criticisms of his procedural planning theory voiced by various theorists and enjoined by the authors of the call for papers for the conference. The paper argues that the misgivings voiced by critics have their parallel in ethical theory and develops the view that procedural rationality and utilitarianism share an ethical principle. The paper concludes with a call for an end to sterile debate and an acceptance of different modes of argument. 相似文献
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