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Summary In the Weddell Sea, several biochemical and physiological characteristics of copepodite stage III to adult females of Calanus propinquus from the surface layer (0–100 m) and the deep layer (500–1,000 m) were compared at a time of high phytoplankton abundance (February) and a month later, when chlorophyll concentration was much lower and older copepodite stages had migrated to their overwintering depth. Daily rations of surface animals, estimated by the gut fluorescence method, varied from 0.8% to 7.8% body carbon (increasing with phytoplankton concentration). Respiration rate (calculated from measurements of electron-transport-system activity) and lipid and protein body content of animals inhabiting the surface layer decreased from February to April. Deep water animals (stage V and adult females) were characterized by high lipid and protein content; their respiration and excretion rates were much lower than in surface copepods. Our calculation showed that they could survive without an additional source of energy for 8–9 months. Based on our own and published data on bio-chemistry and physiology the possibility of a two-year life cycle is suggested.  相似文献   

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Parasite-specific IgE antibody response was examined in Strongyloides ratti-infected rats. The results showed that the parasite-specific IgE antibody response was generated after a primary infection. However, repeated infections rather depressed the level of parasite-specific IgE antibody in the serum. Immunization limited to specific stages of the parasite revealed that stimulation of parasite-specific IgE antibody was related to the intestinal adult stage. On the other hand, depression of IgE titers was related to the tissue-migrating larval stage. The capacity of the each stage of the parasite to induce specific IgE response may be related to the variable results of the IgE responses in human strongyloidiasis.  相似文献   

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SUMMARY. The life cycle of Trichocorixa verticalis interiores was studied in six Saskatchewan saline lakes. A detailed study of the timing of the stages in the life cycle showed that T. v. interiores has a life cycle which differs from that of all other Corixidae. This species overwinters solely in the egg stage. Females oviposit in the late summer and all adults die in the fall. The eggs, which remain in a pre-blastokinesis stage of embryonic development until the following spring, are prevented from developing in late summer by diapause which lasts approximately 2 months. Although diapause terminates in October, embryonic development does not occur in cold water during the winter months. Experimental results indicate that exposure to cold is not necessary to break diapause.  相似文献   

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Definition and classification of the arterial hypertension in pregnancy are discussed. An emphasis is on the problems of differential diagnosis between pre-eclampsia and other forms of hypertension. Use of hypotensive drugs in pregnant patients with particular reference to emergencies is also discussed. The treatment of pregnant women with hypertension is still a problem which require close co-operation of both an obstetrician and internist. Follow-up after labour is GP duty to find out if the patient remains hypertensive. If so, etiology of the disease should be again searched.  相似文献   

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In an attempt to clarify the nature of the "menopausal syndrome" a survey of symptoms was carried out by means of postal questionnaires in a population sample of 1120 women and 510 men. Special care was taken to avoid letting the participants know that the survey was mainly concerned with the menopause. Response rates were 72% for women and 68% for men. Analysis of patterns of symptoms by age and sex showed that peaks of prevalence of flushing and sweating were closely associated with the mean age of menopause, coinciding with it or occurring a little after it. Less impressive peaks of prevalence of a group of minor mental symptoms were associated with an age just preceding the mean age of menopause. Complaints about aching breasts, irritability, and low backache diminished after the menopause. No association with the menopause was found for various other symptoms. The results of this study support the view that the menopausal syndrome exists but do not, of course, provide any evidence concerning the effectiveness (or safety) of hormone treatment.  相似文献   

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H2S is produced as a main end-product of anaerobic mineralization in anoxic, sulphate-rich environments by a diverse population of sulphate-reducing bacteria. The sulphate reducers can carry out an almost complete oxidation of detrital organic matter to CO2. The H2S consequently becomes an important electron carrier from the anoxic to the oxic world. Thiobacilli and other colourless sulphur bacteria have the potential to oxidize the H2S at the oxic-anoxic interface in sediments or stratified waters, but their role is still poorly understood. A comparison of sulphide oxidation processes in the chemoclines of the Black Sea, the Solar Lake and in A beggiatoa mat indicated that depth scales and retention times of coexisting O2 and H2S regulate the bacterial involvement in the sulphide oxidation. The H2S specialists, Beggiatoa and Thiovulum, are optimally adapted to compete with the autocatalytic oxidation of H2S by O2. Microelectrode measurements show retention times of O2-H2S in the bacterial mats or veils of less than 1 s. In photic chemoclines of stratified waters or sulfureta, the phototrophic sulphur bacteria or cyanobacteria interact with the sulphide oxidation at the O2-H2S interface. Short cycles between H2S and intermediate oxidation products, So or S2O2 3-, are created. The bacteria of the sulfuretum are highly adapted to the diurnal rhythm of light, O2 and H2S.  相似文献   

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To achieve more sustainable production and consumption patterns, it is mandatory to consider the environmental implications of the whole supply chain of products, both goods and services, their use and waste management, i.e. their entire life cycle from “cradle to grave”. The International Reference Life Cycle Data System (ILCD) Handbook provides governments and businesses with a basis for assuring quality and consistency of life cycle data, methods and assessments.  相似文献   

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An intra-species comparison of the life history of various populations ofPolystichum tripteron was undertaken in Hokkaido and Honshu in Japan with respect to some leaf-size characters and fertility during sporophyte development. The developmental process of sporophytes was quantitatively estimated by counting the number of venation (NV: number of midrib branches of the leaf). The mean NV of the fertile leaves decreased slightly with increasing altitude on Mt. Teine near Sapporo and with increasing latitudes from Honshu to Hokkaido. The blade length was longer at any NV in Hokkaido populations than in those of southern Honshu. Longer blade (BL) and pinna length (PL) and lesser number of pinnules of the lowest pinna (NPLP) versus NV were observed in leaf populations from Hokkaido than in those from southern Honshu. The maximum values of lowest pinna length (LPL), NV, number of costa branches (NVLP) and number of pinnule (NPLP) were larger in southern Honshu than in Hokkaido. In the course of leaf-shape formation represented by the ratio of PL to BL versus NV, the Kyoto population seemed to be more differentiated into long-lanceolate fronds than did the Hokkaido population. Initiation of fertility in the sporophyte development and the maximum NV seemed to decrease with increasing altitudes and latitudes in Japan. Contribution No. 2885 from the Institute of Low Temperature Science, Hokkaido University.  相似文献   

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