共查询到20条相似文献，搜索用时 15 毫秒
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《Geobios》1987,20(5):675-678
Up to now the top of the marine miocenic sediments 0205 was thought to be white limestones, the so-called “molasses blanches, which stratigraphic position has been modified according to previous authors from the Langhian to Tortonian. We found, overlying the «molasses blanches, a thin marly-sandy formation very well dated of the top of the Langhian by microfauna and nannoplancton. This formation represents the most recent marine miocenic deposits known at this time in the St Florent basin. 相似文献
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《Annales de Paléontologie》1998,84(1):53-69
A section at the top of Upper Callovian deposits at Louesme (district of Montigny-sur-Aube, Côte-d'Or, France) reveals an unbroken series of strata between the top of the Athleta zone and the base of the Lamberti zone (Upper Callovian). A few specimens of Aspidoceratinae, collected with primitive Quenstedtoceras, are refered to Euaspidoceras ferrugineum Jeannet (1951). The characters of this species, which was created for individuals collected from the Herznach Mine (Northern Switzerland), are poorly defined from the Swiss material and little is known for this stratigraphic extent. The new find provides information about the ontogeny and the stratigraphic extent of Euaspidoceras ferrugineum (base of the Henrici subzone) and helps refine the phylogenic scheme of the European Callovian Aspidoceratinae. It also casts new light of the faunal content of the Herznach C. level, which can be interpreted as a level of concentrated faunas. 相似文献
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Sans résuméavec la collaboration technique de MmeVignal, biologiste 相似文献
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《Option/Bio》2008,19(400-401):10
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A. Sournia 《Hydrobiologia》1968,31(3-4):545-560
Summary A list of 152 Diatoms and 158 Dinoflagellates is given and its biogeographic composition is discussed. Some quantitative data are presented: cells counts after sedimentation, spectrophotometric determination of plant pigments, and in situ primary production measurement using 14-C method. A nycthemeral study, carried out during 30 hours, shows that chlorophyll a values are highest between 15.00 and 21.00, and that photosynthesis increases from morning to evening.
Quelques nouvelles données sur le phytoplancton marin et la production primaire à Tuléar (Madagascar)相似文献
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Jean Costentin 《PSN》2004,2(2):14-23
Among all the drugs of abuse cannabis is the only one containing an active principle that can be stored in the body for several weeks, delta-9-Tetrahydrocannabinol (Δ9-THC). It induces both psychic and physical dependency, which are masked because the disappearance of Δ9-THC from plasma corresponds to its storage in lipids, especially in cerebral lipids. In the brain Δ9-THC mimics, in a non regulated, diffuse and intense manner, the neuromodulation which endocannabinoids (anandamide, 2-arachidonyl-glycerol, etc.) physiologically und subtly exert through the stimulation of specific receptors, the so-called CBl receptors. These receptors have an influence on a great variety of psychological functions. For instance, at the hippocampal level receptor reserve is high, and it allows the development of a maximal response even though only a low proportion of these receptors are stimulated. This occurs even for low doses of Δ9-THC. The desensitization / down regulation of these receptors has no functional consequences since they always remain numerous enough to ensure the function. Thus the Δ9-THC-induced cognitive disturbances persist as long as cannabis use persists. On other systems, without CBl receptor reserve, the long lasting use of Δ9-THC induces a desensitisation / down regulation of CBl receptors, leading to a tolerance to its effects. 相似文献
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B. Hermann 《Genetica》1973,44(4):579-587
The chromosome complement of Meriones tristrami Thomas (Rodentia, Gerbillinae), the Israel desert jird, studied by the new technique of chromosome identification (Q and G banding) is described. The diploid number is 72. There are two pairs of submetacentric autosomes (1 and 2) and 33 pairs of acrocentric autosomes. The X chromosome is the largest submetacentric and the Y is the fourth in length among the submetacentric chromosomes of the karyotype. The Fundamental Number (F.N.) is therefore 78 and not 76 as described by Matthey in 1957.
(Travail effectué avec l'appui du Fonds de la Recherche Scientifique Médicale). 相似文献
(Travail effectué avec l'appui du Fonds de la Recherche Scientifique Médicale). 相似文献
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Jean Costentin 《PSN》2004,2(3):20-28
After delta-9-tetrahydrocannabinol (Δ9-THC) has supported the anandamidergic tone, thereby increasing its anxiolytic and antidepressant effects, it loses its efficacy in this respect. Anxious and/or depressive troubles which could have prompted the abuse of cannabis then reappear more intensely. They peak when consumption is completely stopped. Cannabis consumption may contribute to polydrug abuse. Its association with tobacco makes it more difficult to give up both substances of abuse. Cannabis use encourages the consumption of alcohol and this association is especially deleterious as regards car accidents. Δ9-THC sensitises cannabis abusers to perceive the appetitive effects of heroin in a more acute manner. Cannabis consumption also makes withdrawal symptoms associated with heroin abuse more severe. Cannabis appears to be able to reveal schizophrenia in patients bearing a neurobiological vulnerability substratum to this disease. It seems especially appreciated by people suffering of negative symptoms of schizophrenia, which could prompt them to abuse cannabis, and then triggering the positive symptoms of the disease. These positive symptoms are particularly resistant to treatment with antipsychotic medication when cannabis abuse is continued. All this recent data necessitates extreme care with this drug of abuse, whose dangerous effects are becoming more and more known. 相似文献
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Sans résumé 相似文献
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