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861.
Eleven drinking water treatment plants, located downstream of textile plants or pulp and paper mills, have been sampled monthly during a year for the analysis of 17 nonylphenol ethoxylates (NP1-17EO) and two nonylphenoxycarboxylic acids (NP1-2EC). At all but one plant, results in the drinking water, for the sum of these 19 substances, range between below detection levels and 6.7 microg/l. Annual means are between 0.02 and 2.8 microg/l. At the other plant, the yearly average concentration is 10.4 microg/l and the monthly maximum is 43.3 microg/l. In the surface (pre-treatment) water, the annual mean concentrations of the 11 plants range between 0.14 and 17.8 microg/l and the recorded instantaneous maximum is 55.3 microg/l. According to Canadian health authorities, drinking water is a negligible route of human exposure to nonylphenolic compounds, even at the highest concentrations found in this study. After transformation of the data into nonylphenol equivalents, about 20% of the surface water samples exceed the Canadian 1 microg/l nonylphenol water quality guideline for the protection of aquatic life. Some results also exceed Québec's 6 microg/l nonylphenol guideline. The efficiency of the plants in removing nonylphenolic compounds from drinking water is highly variable, ranging from 11% to 99%. 相似文献
862.
The main objective of this study was to examine the relationship between perceived support and affective commitment, and the linkages between these constructs and some of their common antecedents and consequences. More precisely, using a sample of 238 employees, we conducted a longitudinal study to examine the linkages between the favorableness of intrinsically and extrinsically satisfying job conditions, perceived organizational support, perceived supervisor support, affective commitment to the organization and supervisor, and turnover. Affective commitment to the supervisor was found to completely mediate the effect of perceived supervisor support on turnover, whereas neither perceived organizational support nor organizational affective commitment were significantly related to turnover. Perceived organizational support partially mediated the effect of favorable intrinsically satisfying job conditions on organizational affective commitment and fully mediated the effect of extrinsically satisfying job conditions on organizational affective commitment. Finally, perceived supervisor support totally mediated the effect of favorable intrinsically satisfying job conditions on affective commitment to the supervisor. As a whole, findings suggest that exchange relationships between employees and their supervisors should be further investigated in future turnover research. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
863.
864.
E. Menzel Max Schmidt R. Bünsow Gottwalt Christian Hirsch 《Die Naturwissenschaften》1962,49(14):335-336
865.
Anne-Marie Boulay Christian Bouchard Cecile Bulle Louise Deschênes Manuele Margni 《Mitigation and Adaptation Strategies for Global Change》2002,7(4):417-418
Subject Index
Subject Index 相似文献866.
The Science of Nature - 相似文献
867.
Christian Hoffmann 《Die Naturwissenschaften》1965,52(14):436-437
868.
Deep-sea hydrothermal vent ecosystems host both symbiotic and non-symbiotic invertebrates. The non-symbiotic vent fauna is
generally assumed to rely on free-living chemoautotrophic bacteria as their main food source but other sources such as detritus
have recently been suggested to be a part of the invertebrate diets. Little is known about how food availability influences
the distribution of vent organisms on a small scale. In addition, the feeding ecology and role of small, often numerically
dominant invertebrates, the meiofauna is poorly understood at vents. In this study, we used stable carbon and nitrogen isotopic
analysis to investigate the role of particulate detritus in the diets of macro- and meiobenthic invertebrates within three
vent assemblages at Axial Volcano, Juan de Fuca Ridge, and Northeast Pacific. Particulate organic matter of a detrital origin
became more important in the diet of invertebrates in assemblages typically associated with low-hydrothermal flow intensities.
Meiobenthic species occupied several different feeding guilds and trophic levels in the assemblages investigated. We conclude
that small-scale spatial variability in food sources is an important feature of vent food webs and that spatial patterns observed
here and elsewhere are shaped by variations in hydrothermal discharge. 相似文献
869.
870.