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971.
972.
A computer simulation model was developed to investigate nitrogenfluxes associated with microbial interactions in plankton communities.A short time scale was used, appropriate to the build-up anddecline of phytoplankton blooms in temperate shelf waters aftera mixing or upwelling event. The model depicts a continuum ofevents, many of which have been observed in coastal, upwellingand oceanic systems, including two phytoplankton peaks correspondingto ‘new production’ and ‘regenerated production’.It predicts that nitrogen loss through sedimentation of phytoplanktonand faeces may result in a smaller bloom with a delayed onsetand prolonged duration. Microbial regeneration of nitrogen wasfound to be important in sustaining the middle stages of a phytoplanktonbloom, whereas micro- and meso-zooplankton regeneration occurredtowards the end of the bloom.  相似文献   
973.
Volatiles from the epicuticular wax of watercress were collected by ether washing and examined using gas chromatographic and mass spectrometric analysi  相似文献   
974.
975.
The distribution of regular secondary structures, viz. α-helices and β-strands, along the length of over 70 properties whose secondary structural details have been reported, has been analysed. The occurrence of these regular structures tends to be a maximum at the N- and C-termini. Our analysis suggests that both these free ends could possibly serve as nucleating centers for secondary structures and could play an important role in the folding of proteins.  相似文献   
976.
The flavonoids of five Geranium, fourteen Erodium and four Monsonia species were studied. Quercetin was the most common aglycone with lesse  相似文献   
977.
It was shown that at a continuously increased level of endogenous glucocorticoids (injection of ACTH) in thymectomized and B mice the degree of inhibition of CFUs migration, that was observed in T-deficient mice without ACTH injection, did not increase. With T-deficiency the stimulatory effect of the hypocorticoid state (adrenalectomy) on the CFUs migration persisted but was less pronounced than in animals with intact thymus.  相似文献   
978.
979.
980.
Experiments have shown that the resistance of adults of the desert locust ( Schistocerca gregaria ) and the African migratory locust ( Locusta migratoria migratorioides ) to DNC applied as a contact poison to the ventral surface of the abdomen is directly related to their body weight, irrespective of age or sex.
Varying the site of application of the insecticide had little effect on the susceptibility of the insects except when the dose was applied to the wings or femur, these being less effective sites of entry for the poison.
Increasing the post-treatment temperature from 25 to 36°C. had no noticeable effect on mortality, but the speed of action of the insecticide was much increased.  相似文献   
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