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Toxicity of copper to phytoplankton depends on the physicochemical form of the metal. Organic substances liberated into the culture medium by the phytoplankton species Cricosphaera elongata are able to detoxify and complex copper. The molecular weight range of these organic substances has been determined by ultrafiltration. 相似文献
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Daniel C. L. Satgé Marie-Annick Laumond François Desfarges Marie-Pierre R. Chenard 《黑龙江环境通报》2001,21(4):284-288
A therapeutic abortion was conducted on a 17-week-old male fetus with a large umbilical cord teratoma associated with an exomphalos. A review of the literature revealed ten other cases of umbilical cord teratoma and shows that these tumors have a very polymorphic presentation. Four fetuses and infants died from various causes indicating that there is a need for close follow-up of pregnancies with umbilical cord teratoma. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Hausberger M Fureix C Bourjade M Wessel-Robert S Richard-Yris MA 《Die Naturwissenschaften》2012,99(4):291-302
Play remains a mystery and adult play even more so. More typical of young stages in healthy individuals, it occurs rarely at adult stages but then more often in captive/domestic animals, which can imply spatial, social and/or feeding deprivations or restrictions that are challenging to welfare, than in animals living in natural conditions. Here, we tested the hypothesis that adult play may reflect altered welfare states and chronic stress in horses, in which, as in several species, play rarely occurs at adult stages in natural conditions. We observed the behaviour (in particular, social play) of riding school horses during occasional outings in a paddock and measured several stress indicators when these horses were in their individual home boxes. Our results revealed that (1) the number of horses and rates of adult play appeared very high compared to field report data and (2) most stress indicators measured differed between ‘players’ and ‘non-players’, revealing that most ‘playful’ animals were suffering from more chronic stress than ‘non-playful’ horses. Frequency of play behaviour correlated with a score of chronic stress. This first discovery of a relationship between adult play and altered welfare opens new lines of research that certainly deserves comparative studies in a variety of species. 相似文献
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