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1.
David G. Frey 《Hydrobiologia》1980,69(1-2):83-123
Two readily distinguishable species of Chydorus sphaericus sens. lat. occur in Salmon Lake, Montana, differing from each other in size and shape of rostrum, headpore configuration, frequency of doubling of teeth on the postabdomen, pattern of reticulation of the shell, and morphology of the mature male, especially the postabdomen, postabdominal claws, copulatory hooks, and rostrum. In any such comparisons, individual specimens are not sufficient; populations are needed to sort out morphological characters associated with instar and sex and character's that change with increasing body size. Comparison of population structure and stage of reproduction can be accomplished by a size-frequency distribution and by specific morphological characters that enable the three male instars to be recognized individually.One species, thought at first to be Chydorus herrmanni, is very close to Chydorus sphaericus sens. str. from Denmark. The other taxon with a short, generally blunt labrum, is described as the new species Chydorus brevilabris. Because of morphological diversity among the entities currently listed as Chydorus sphaericus from around the World, it is certain that a complex of species is represented. To facilitate the eventual resolution of this problem, the population in Sjaelsø, Sjaelland, Denmark has arbitrarily been selected as the standard of comparison, and from this population a neotype and several allotypes have been designated. Cursory examination of various available populations suggests that C. sphaericus sens. str. and C. brevilabris represent a major dichotomy in the sphaericus complex, each branch consisting of an unknown number of closely-related species. Cautions are voiced against assuming that Chydorus sphaericus is a single cosmopolitan and ubiquitous species.This study has been aided by grant GB-29725 for the work in Denmark in 1971–72 and by my present grant DEB 76-20237, both from the National Science Foundation. I am indebted to D. F. Brakke for the samples from Salmon Lake and neighboring localities in Montana and information concerning these localities, and to Brenda J. Hann for dissections and drawings of trunk limbs and help in their interpretation. I am also indebted to Geoffrey Fryer, whose innocent inquiry precipitated this study.  相似文献   

2.
The new scleractinian coral genusHexasmiliopsis is described on the basis of material from the Early Aptian (Early Cretaceous) of Murcia (Spain). The new genus of the Heterocoeniidae family is characterised by its solitary growth form, a very strong main septum and the presence of apophysal septa. It is closely related to the generaHexasmilia (phaceloid growth form),Rodinosmilia andTiarasmilia (both without main septum). The genus is monospecific and represents only the type species,Hexasmiliopsis saldanai.   相似文献   

3.
The development of socio-economic activity over the past ten years in the Mediterranean region has induced severe changes in the main natural forest ecosystems.In the northern Mediterranean, rural depopulation has accelerated since the end of the second World War, particularly since the establishment of Common Market agricultural policies, and led to an under-utilization of species causing a strong biological resurgence of the forest, even at high altitudes. This means that, at the present time, the extension of expansion model coniferous forests is favored by their capacities for spatial, biological and ecological selection. Along with this, the under-utilization of sclerophyllous (resistance model) and deciduous (stabilization model) oak coppices has led to the establishment of new forest structures and architectures which are notably different from the main climatic groups defined up to now by phytosociological and synchronic methods. Two new forms of disturbances have appeared:  相似文献   

4.
5.
A new species of Hypostomus with spoon-shaped teeth is described from the Rio Cupari basin, a right margin affluent of the lower Rio Tapajós, Pará State, Brazil. The new species inhabits rocky bottom areas in the main channel of Rio Cupari and its tributaries. The new species can be distinguished from all its congeners, except from the Hypostomus cochliodon group, by having six to eight spoon-shaped teeth, dentaries angled at less than 80° and the absence of a notch between the hyomandibular and the metapterygoid. The new species is distinguished from all species of the H. cochliodon group by its unique colour pattern, containing dark vermiculations on head and anterior portion of the trunk, and by the absence of medial buccal papillae.  相似文献   

6.
7.
The new yeast species, Sporobolomyces lactosus, transformed D-xylose into a mixture of disaccharides. Hydrolysis of this mixture yielded D-glucose only. The main component of disaccharide mixture was α,α-trehalose.  相似文献   

8.
Summary A new pennellid genus,Exopenna, is established on the basis of two specimens of a new species,E. crimmeni, recovered from a deep-sea cod,Antimora, caught in the North East Atlantic. It is ectoparasitic and is diagnosed by the combination of a straight body, tightly coiled egg sacs and flattened, plate-like antennary processes. Another new species,Peniculus elongatus, is described from Australian waters and new records ofP. fistula andLernaeenicus ramosus further increase the known pennellid fauna of that region. A preliminary analysis of the phylogenetic relationships of the pennellid genera is undertaken and a partially resolved cladogram produced which identifies the main generic groupings. ac]19850522  相似文献   

9.
Balanced optimal two level fractional factorial designs of resolution V have been reported in series of papers by SRIVASTAVA and CHOPRA (1971a, 1971b, 1974) and CHOPRA and SRIVASTAVA (1973a, 1973b). The optimality criterion considered by them is the trace optimality which implies minimisation of the average variance of the estimated effects which include the general mean μ, main effects, Ai, and first order interactions, Aij. In the present work some new optimal designs have been obtained on the basis of a modified criterion of trace optimality. The criterion requires minimisation of the average variance of each of the main effects, two factor interactions, etc. separately instead of minimising average variance of all the estimated effects.  相似文献   

10.
Erysimum damirliense, a new species of Brassicaceae from Zanjan and Ardebil provinces (northwest Iran) is described and illustrated. The new species resembles E. uncinatifolium and E. elbrusense, but is easily recognized by its life form, basal leaf margin, indumentum of cauline leaves, number of flowers in the main raceme, fruit width and style length. Phylogenetic analysis of internal transcribed spacer (ITS) DNA sequences confirm that the new species is distinct from morphologically similar species.  相似文献   

11.
A new species of Campylocentrum from the Colombian Andes, C. guarinae, is described, illustrated and placed within a key to Colombian species of the genus. The new species resembles C. lansbergii from which it differs in vegetative and floral characters. The main differences between these species are described and illustrated.  相似文献   

12.
A new species, Psygmophyllum intermedium, sp. nov., is described based on macromorphological and epidermal and cuticular characters. The main patterns of the intraspecific (intrapopulational and ontogenetic) variability of the P. intermedium leaves are established. A new combination, Psygmophyllum interruptepinnatum (Kutorga) Naugolnykh, comb. nov., is proposed.  相似文献   

13.
418篇医疗纠纷文献回顾性分析   总被引:2,自引:0,他引:2  
??????? 目的 通过总结医疗纠纷产生的主要原因,提出防范和处置医疗纠纷的要点,为和谐医患关系、构建平安医疗环境提供依据。方法 综合运用文献调查法和统计学方法收集、整理了2003—2012年418篇医疗纠纷相关文献资料,回顾性分析了近十年来医疗纠纷研究的主要侧重方向——原因分析、防范对策及处理机制。结果 关于医疗纠纷的研究呈现出新特点、新趋势,其研究领域不仅局限于医疗卫生层面,而且涉及到社会、伦理、心理学等方面,如何全面、有效防范和处置医疗纠纷成为当前医院管理的重点之一。结论 建立预警机制,干预可控节点,现场高效处置,能够有效防范医疗纠纷。  相似文献   

14.
Brucellosis is a zoonosis caused by bacteria of the genus Brucella, which includes nine species: B. melitensis (goats and sheep as the main reservoir hosts), B. abortus (cattle), B. suis (pigs), B. neotomae (desert woodrats), B. ovis (sheep), B. canis (dogs), B. ceti (whales), B. pinnipedialis (pinnipeds), and B. microti (Microtus voles). The epidemic and epizootic situation with brucellosis is accounted for by farm animals, which are the carriers of three main pathogens (B. melitensis, B. abortus, and B. suis). Their ubiquitous distribution is the factor determining global prevalence of the above Brucella species on all continents and in the overwhelming majority of countries. Consistent with the expansion of the pathogen ecological range are the 1990s findings of new Brucella species in marine mammals (whales and pinnipeds) and in some rodents. These bacteria proved to be also pathogenic for terrestrial mammals and humans. All Brucella-infected animals considered in the paper are tentatively divided into two groups. The first includes most of the wild and domestic animal species, birds, and ticks that acquire the infection farm animals, the main hosts of Brucella. The second group includes animals (wild reindeer, hares, bison, and probably saiga antelopes, dogs, and marine mammals) which may carry Brucella regardless of infection prevalence in the main hosts.  相似文献   

15.
Aims: To find new antifungal agents among essential oils from Brazilian Croton species. Methods and Results: Plant leaves were steam distilled and the obtained essential oils were analyzed by gas chromatography/mass spectroscopy. The main constituents were estragole and anethole for Croton zehntneri, methyl-eugenol and bicyclogermacrene for Croton nepetaefolius and spathulenol and bicyclogermacrene for Croton argyrophylloides. The antifungal activity of essential oils was evaluated against Candida albicans, Candida tropicalis and Microsporum canis by the agar-well diffusion method and the minimum inhibitory concentration (MIC) by the broth microdilution method. Essential oils of Croton species demonstrated better activity against M. canis. Among the three plants C. argyrophylloides showed the best results, with MIC ranging from 9 to 19 μg ml−1. The acute administration of the essential oil up to 3 g kg−1 by the oral route to mice was devoid of overt toxicity. Conclusions: The studied essential oils are active in vitro against the dermatophyte M. canis and present relative lack of acute toxicity in vivo. Significance and Impact of the Study: Because of its antifungal activity and low toxicity, the essential oils of studied Croton species are promising sources for new phytotherapeutic agents to treat dermatophytosis.  相似文献   

16.
The authors present new data on spatial-temporal distribution of the northern red-backed vole (Myodes rutilus Pallas) and the large-toothed redback vole (M. rufocanus Sundervall) for the main habitat types in the Khanka Plain, Primorskii Krai. Data on seasonal and long-term abundance for 2003-2005 are reported. The study was stimulated by contradictory data on the distribution of the Myodes voles in the Khanka Plain.  相似文献   

17.
目的 梳理肿瘤多学科诊疗团队研究关键主题,分析研究热点和趋势。方法 应用CiteSpace对肿瘤多学科诊疗团队研究进行可视化分析。结果 相关文献共2 160篇,关键文献10篇,主要主题聚类15个,突现术语29个。结论 肿瘤MDT研究主要集中于多学科诊疗团队的构建及运行、推行情况、效果评价,研究前沿如提高实施效率、成本—效果分析、随机对照研究等,为中国肿瘤多学科诊疗团队研究和发展提供了新视角。  相似文献   

18.
Deprea is a neotropical genus that comprises 51 species. Recent work based on molecular data has explored its monophyly and interspecific relationships, but the relationships amongst Deprea species were not entirely elucidated. The inclusion of more accessions and molecular markers in phylogenetic analysis is likely to produce more supported hypotheses. Therefore, the main objective of this study was to perform a combined phylogenetic analysis of Deprea including seven new samples representing six species and one more DNA plastid marker than in previous studies. In that process, a new species of Deprea from Colombia was discovered and is described and illustrated here. Deprea teresitae Deanna & A. Orejuela, sp. nov. is morphologically similar to D. dilloniana and phylogenetically closely related to D. hawkesii and D. harlingiana. This new species is distinguished by the combination of short calyx lobes, non-mucronate anthers, long staminal filaments and corolla lobes, and elongated appressed fruiting calyx around a subglobose green berry. The new phylogenetic results are presented, including discussion on phylogenetic interspecific relationships, taxonomy, geographic distribution, and conservation status from D. teresitae. The synonymy of Deprea sylvarum subsp. novogranatensis under D. glabra is also proposed and an identification key to the 10 Deprea species distributed in Colombia is included.  相似文献   

19.
Abstract: The retiolitid graptolite Reticuloplectograptus serpaglii gen. et sp. nov. from the Gorstian, lower Ludlow, has been found in two localities: the Bartoszyce borehole of Poland (Baltica), and the Bykoš section, Barrandian, Czech Republic (PeriGondwanan Europe). The Polish material is isolated and was studied under the SEM. The main characters of Reticuloplectograptus are similar to those of Plectograptus: an asymmetrical ancora, simple ancora umbrella with an incompletely developed rim and parallel ventral walls with mid‐ventral lists. The paired genicular processes of the new species are similar to but much wider than those of Plectograptus trijunctus and Plectograptus robustus. The main differences between the new genus and Plectograptus are the dense ancora sleeve wall and small proximal lateral orifices of the former. These primitive characters suggest that Reticuloplectograptus might be ancestral to genera with strong reduction in the proximal end, such as Plectograptus, Valentinagraptus and Kirkigraptus. However, Reticuloplectograptus appeared stratigraphically later than Plectograptus, indicating that this aspect of retiolitid evolution is more complicated, needing further study.  相似文献   

20.
Aims: The main aims of this study were to clone and express a new outer membrane protein U (OmpU) from a pathogenic Vibrio harveyi SF‐1 and investigate its immune efficiency as a vaccine candidate against V. harveyi infection in turbot (Scophthalmus maximus). Methods and Results: In this study, a new gene, ompU was cloned from the genomic DNA of pathogenic V. harveyi SF‐1. The ompU gene encoded a 35 kDa protein, which was purified by Ni‐NTA His‐Bind Resin column. A DNA vaccine was constructed by inserting ompU gene into pEGFP‐N1 plasmid. Turbot were injected intramuscularly with the purified OmpU protein and the recombinant pEGFP‐N1/ompU plasmid, respectively. The fish vaccinated with the purified OmpU protein were completely protected with a relative per cent of survival (RPS) of 100% against pathogenic V. harveyi infection. Efficient protection was also found in the pEGFP‐N1/ompU vaccinated group, with a RPS of 51·4%. Significant specific antibody responses were detected in the vaccinated turbot by indirect enzyme‐linked immunosorbent assay. Conclusions: A new OmpU was cloned and expressed. Both OmpU protein vaccine and DNA vaccine showed good immune protections in turbot. Significance and Impact of the Study: The OmpU was identified to be a new effective vaccine candidate and could be used as subunit vaccine and DNA vaccine for disease control caused by pathogenic V. harveyi.  相似文献   

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