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21.
22.
LEE Belbin 《Biodiversity and Conservation》1995,4(9):951-963
Multivariate analysis provides an effective context for the examination of some significant aspects of biodiversity and conservation. The framework is a multidimensional space that integrates sample sites, taxa and environments. This approach enables terms such as representativeness, complementarity and irreplaceability to be integrated within an intuitive and practical framework for reserve design. Cluster analysis is proposed to determine what is there by defining a set of complementary clusters. These clusters are sampled in a representative manner; from the core outward. The degree of irreplaceability of a site is defined as the multivariate distance of each potential reserve site to its nearest neighbour. 相似文献
23.
1982年在四川省采集吸血蠓时,发现库蠓属(culicoides)两个新种。现记述如下。新种模式标本分别保藏于四川省成都铁路局中心卫生防疫站和中国科学院动物研究所。 相似文献
24.
LEE DRUMMOND 《American anthropologist》1977,79(4):842-868
Recent work on oral narrative has emphasized differences in textual and performative approaches, which in turn has tended to widen the distinction between two fundamental categories of anthropological thought: structure and process. This paper argues that, at least for the interpretation of South American myth, an integrated approach is essential. After reviewing the epistemological basis of current problems in myth studies, the paper attempts a structural analysis of myths with the theme of a metamorphic conjugal union between human and nonhuman. Processual considerations are introduced in the form of syncretic myth, and the argument is advanced that there exist syncretic transformations of a structural nature. Identifying these provides the beginnings of a bridge between structure and process, and leads to an examination of the performative context of the subject myth. Other narrative genres, dealing with explicitly ethnic concepts, are implicated in the processual sequence of the telling and interpretation of the tale. The attempted synthesis of structure and process in narrative analysis leads to an engagement with two difficult problems: the relationship between ethnicity and kinship; and the transition from myth to history. [myth, structure, process, ethnicity, kinship] 相似文献
25.
Taxonomy and Description of Vibrio fluvialis sp. nov. (Synonym Group F Vibrios, Group EF6) 总被引:9,自引:1,他引:8
A numerical taxonomic study has been carried out to establish the relationship of group F to other biochemically similar organisms within the family Vibrionaceae. A total of 154 strains were examined including 59 of group F. Out of 114 characters determined for each strain 100 were used to compute average Euclidean distances between strains. Four methods of clustering were used, all of which gave very similar results.
Strains resembling Vibrio anguillarum fell into clusters corresponding to V. anguillarum, Beneckea nereida and a previously unrecognized group, phenon 5. Strains of the Aeromonas hydrophila/punctata group formed a heterogenous phenon within which certain subdivisions, perhaps artificial, could be discerned.
Group F strains all fell in one closely-knit cluster distinct from all the species of Vibrio, Aeromonas, Plesiomonas and Photobacteriwn studied. Group F strains could be divided into two biovars, I and II. Both biovars are present in aquatic, particularly estuarine, environments throughout the world but biovar I strains have also been isolated from humans with diarrhoea. It is concluded that group F is a synonym of group EF6 and that the strains within these groups should be classified in a new species named Vibrio fluvialis. The type strain is NCTC 11327. 相似文献
Strains resembling Vibrio anguillarum fell into clusters corresponding to V. anguillarum, Beneckea nereida and a previously unrecognized group, phenon 5. Strains of the Aeromonas hydrophila/punctata group formed a heterogenous phenon within which certain subdivisions, perhaps artificial, could be discerned.
Group F strains all fell in one closely-knit cluster distinct from all the species of Vibrio, Aeromonas, Plesiomonas and Photobacteriwn studied. Group F strains could be divided into two biovars, I and II. Both biovars are present in aquatic, particularly estuarine, environments throughout the world but biovar I strains have also been isolated from humans with diarrhoea. It is concluded that group F is a synonym of group EF6 and that the strains within these groups should be classified in a new species named Vibrio fluvialis. The type strain is NCTC 11327. 相似文献
26.
SUSAN G LANGRETH JONATHAN D. BERMAN G. PATRICK RIORDAN LINDA S. LEE 《The Journal of eukaryotic microbiology》1983,30(3):555-561
The mechanism of action of antileishmanial compounds is poorly understood. Ultrastructural changes in Leishmania tropica within human macrophages exposed in vitro to Pentostam, pentamidine, amphotericin B, WR 6026, ketoconazole, and Formycin B were examined in these experiments. In Pentostam-treated cultures, some organisms exhibited diminished definition of mitochondrial and other membranes, while other organisms had completely disintegrated. Pentostam-exposed macrophages demonstrated loss of membrane definition in the absence of further alterations; it is therefore hypothesized that impaired macrophage membrane function may contribute towards the effect of this drug against macrophage-contained organisms. Leishmania parasites in pentamidine-treated cultures initially demonstrated swollen kinetoplasts and fragmentation of the kinetoplast DNA core. The initial observed effect of the other four drugs on the parasites was cytoplasmic condensation. These ultrastructural studies suggest that all five non-antimonial drugs may have different mechanisms of action than antimony (Pentostam) against Leishmania. 相似文献
27.
Field-caged and open-plot populations of the aphid Sitobion avenae on winter wheat (cv. Maris Widgeon) were sampled approximately twice-weekly in the summer of 1978. Cage populations began at growth stage 10.2 (Feekes scale) (Zadoks, G. S. 52); they were removed by spraying with pirimicarb at growth stages 10.54 (71), 11.1–11.2 (77) and 11.2–11.3 (85) respectively. All cage populations reduced mean weight per grain but the effect per aphid unit was lowest in the population of longest duration. Although the aphid index in the open plots was higher than that in the early cage treatment, yield was unaffected. Cage infestations affected the breadmaking quality of the grain: percentage flour extraction was reduced and there was an increase in colour, nicotinic acid content and thiamine (vitamin B1) content of the flour; percentage nitrogen in the flour was unaffected but there was a reduction in baking value and in the high molecular weight glutenin content; infestation also reduced α-amylase activity. Different aspects of grain quality did not change in parallel with one another or with yield changes and thus damage thresholds will vary according to the yield/quality measure under consideration. 相似文献
28.
ABSTRACT. The temporal changes in the size and pH of digestive vacuoles (DV) in Paramecium caudatum were reevaluated. Cells were pulsed briefly with polystyrene latex spheres or heat-killed yeast stained with three sulfonphthalein indicator dyes. Within 5 min of formation the intravacuolar pH declined from ~7 to 3. With the exception of a transient and early increase in vacuolar size, vacuole condensation occurred rapidly and paralleled the acidification so that vacuoles reached their lowest pH and minimal size simultaneously. Neutralization and expansion of vacuole size began when vacuoles were GT8 min old. No labeled vacuoles were defecated prior to 21 min after formation but almost all DV were defecated within 1 h so that the digestive cycle of individual vacuoles ranged from 21 to 60 min. Based on these size and pH changes, the presence of acid phosphatase activity, and membrane morphology, digestive vacuoles can be grouped into four stages of digestion. The DV-I are GT6 min old and undergo rapid condensation and acidification. The DV-II are between 4 to 10 min old and are the most condensed and acidic vacuoles. The DV-III range in age from 8 to ~20 min and include the expanding or expanded vacuoles that result from lysosomes fusing with DV-II. The DV-IV are GD21 min old, and since digestion is presumably completed, they can be defecated. The rise in intravacuolar pH that accompanies vacuole expansion suggests that lysosomes play a role in vacuole neutralization in addition to their degradative functions. The acidification and condensation processes in DV-I appear to be unrelated to lysosomal function, as no acid phosphaiase activity has been detected at this stage, but may be related to phagosomal functions important in killing food organisms, denaturing proteins prior to digestion, and preparing vacuole membrane for fusion with lysosomes. 相似文献
29.
Phosphate influx and extracellular phosphatase activity in barley roots and rose cells 总被引:4,自引:0,他引:4
R. B. LEE 《The New phytologist》1988,109(2):141-148
30.
ABSTRACT An assessment on the biological control potential with the fish muddy loaches (Misgurnus mizolepis) was conducted against naturally bred Culex pipiens pollens larvae in four ponds (A, B, C and D) in Busan from July through September, 2001. Predation of the fish at 3 different release rates of 4,5, and 6 fish/m2 resulted in mostly over 90% mosquito control from the first week after treatment through the end of the survey period for 11 weeks. There were no significant difference among the release rates of fish at the 5% level of probability. However, substantial controls of 43.0% and 25.9% were obtained from pond C during the 3rd and 7th weeks after the fish introduction, respectively. The results of those two weeks showed a lower biological control by the introduced larvivorous fishes. This might be due to the presence of heavy organic matters including aquatic weeds and/or severely polluted water from sewage in pond C. The aquatic weeds covered the pond's water surface which may have affected the deterioration of mosquito preying in favor of aquatic weeds. Also, the fishes were observed to avoid severely contaminated sewage water in some parts of ponds A and C where more mosquito larvae were found. 相似文献