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V. I. Monchenko 《Hydrobiologia》2000,417(1):101-107
The problem of cryptic species in Diacyclops bicuspidatus was examined using interpopulation crosses of four populations collected from a: (1) permanent flood lake in Kiev, Ukraine, (2) temporary pool in Kiev, (3) permanent pond in St. Petersburg, Russia (1200 km to north from Kiev) and (4) lake in Crimea (1100 km south of Kiev). The only interpopulation crosses to exhibit fertility were those between the St. Petersburg population and each of the two Kiev populations. The crosses between the Kiev and Crimea populations, between the St. Petersburg and Crimea populations, and between the two Kiev populations were sterile, as evidenced by either nonviable eggs, empty egg membranes or incomplete copulations. The F1 hybrids resulting from the St. Petersburg permanent pond X Kiev flood lake cross were fertile and produced mature F2 offspring. Some data on development times of parental and hybrid lines are presented. The St. Petersburg parental line showed development times almost twice as long as those of the Kiev flood lake population when reared at 10 °C and 20 °C in the laboratory. The F1 offspring of the cross between St. Petersburg females and Kiev floodlake males showed similar development times to females of the St. Petersburg parental lines at both temperatures. The F2 hybrids also showed development times that approximated those of the St. Petersburg parental line. These crossbreeding studies suggest the presence of cryptic species in the D. bicuspidatus inhabiting ecologically different populations in many parts of its large holarctic range. 相似文献
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Charles D. Laughlin 《Human nature (Hawthorne, N.Y.)》1991,2(3):171-213
Ample evidence from various quarters indicates that the perceptual-cognitive competence of the pre- and perinatal human being
is significantly greater than was once thought. Some of the evidence of this emerging picture of early competence is reviewed,
and its importance both as evidence of the biogenetic structural concept of “neurognosis” and for a theory of enculturation
is discussed. The literature of pre- and perinatal psychology, especially that of developmental neuropsychology, psychobiology,
and social psychophysiology, is incorporated, and some of the implications of these data for a theory of enculturation are
suggested.
This paper was presented at the annual meeting of the American Anthropological Association, Washington, D.C., November 1989.
Charles D. Laughlin, Professor of Anthropology at Carleton University, Ottawa, Canada, has done ethnographic fieldwork among
the So of northeastern Uganda and among Tibetan lamas in Nepal and India. He completed postdoctoral studies in neurophysiology
at the Institute of Neurological Sciences, University of Pennsylvania. He is editor of both theNeuroanthropology Network Newsletter and thePre- and Peri-Natal Psychology Journal. 相似文献
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Marc Ledig Adam Holownia Jean-Christophe Copin Georges Tholey Irina Anokhina 《Neurochemical research》1996,21(3):313-317
The aim of this work was to investigate the effect of supplementation of a maternal alcohol diet with a grape extract on glial
cell development. Glial cells were cultured during 4 weeks from cortical brain cells of the new born offspring in DMEM medium
supplemented with fetal calf serum. Enzymatic markers of nerve cell development were measured (enolase isoenzymes and glutamine
synthetase). Since alcohol consumption produces free radicals the antioxidant system superoxide dismutase was also investigated.
Compared to the decrease found in only alcohol treated animals, all parameters except neuron-specific enolase were antagonized
and even stimulated after grape extract supplementation. The effect was more important after only 1 month than 3 months of
treatment. Also in the total brain an alcohol antagonizing effect and a glutamine synthetase activation were found. Our data
demonstrate that addition of a grape extract to the maternal alcohol diet may partially or completely overcome the alcohol
induced retardation of glial cell development. 相似文献
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多功能农业景观:内涵、进展与研究范式 总被引:2,自引:0,他引:2
多功能农业景观是景观尺度下农业多功能性的空间表征,具有生物多样性保护、田园风光留存和地域文化传承等多种重要的非经济功能。构建多功能农业景观是促进区域农业可持续发展与人类福祉提升的重要途径,同时也是多学科交叉的综合性研究。在已有景观生态学研究范式的基础上,探讨了多功能农业景观的内涵和国内外相关研究进展,并提出了"格局-功能-需求-管理"的多功能农业景观研究范式。与此同时,绘制了新研究范式的概念框架,通过划分四大研究模块具体分析了如何基于新研究范式开展多功能农业景观的构建、评价和管理等工作。本研究为实现区域农业景观的可持续发展和阐明多功能农业景观的内在运行机制奠定理论基础提供支持,为乡村生态景观营造关键问题的解决与多功能农业景观的实际构建提供帮助。 相似文献
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