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1.
Cluster analysis of conodont faunas from each of 17 Lower‐lower Upper Devonian zones and subzones (data as reported by Klapper and Johnson, 1980) reveal changing patterns of provinciality. Provinciality, expressed by a differentiation into western Laurussian and proto‐Tethyan biogeographic regions, is moderate in the lower Lochkovian but is low or absent in the upper Lochkovian‐lower Pragian. Provincialism returns in the Pragian and reaches its maximum development during the Emsian. Most Australian faunas are distinct from those of western Laurussia and the proto‐Tethys. Conodont faunas from suspect terranes of western North America display no unusual biogeographic affinities. Provincialism declines during the Eifelian and is only weakly developed in Givetian‐lower Frasnian faunas. Changing global sea level during the Devonian may explain the development of Devonian conodont provinciality. As proposed by Klapper and Johnson (1980), low provinciality is associated with low stands of sea level. Endemic faunas develop in isolated epeiric seas during intermediate stages of sea level rise. High stands of sea level ultimately drown barriers to faunal exchange and prompt a return to low provinciality conditions. 相似文献
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The northern Canadian Cordillera can be divided into three more or less parallel arrayed lithofacies, which from east to west correspond to progrcssively deepening waters. The shallow water, yellow, or orange-weathering carbonates occupy essentially the eastern half of the region and northwestern Yukon. Shallowest water carbonates yield fairly abundant ostracodem faunas, ostracodes, and little else. Slightly deeper water carbonates contain brachiopod faunas rich in individuals but low in generic diversity. The name Howellella-Protathyris Community is applied to the Lower Lochkovian shallow water faunas: the Sieberella-Nymphorhynchia-Athyrhynchus Community is the approximate Upper Pragian-Zlichovian equivalent. Deep water calcareous shales and limestones occupy a narrow band and yield faunas rich both in number and diversity. These faunas are designated the Skenidioides-Spirigerina-Vagrania Community and are recognized through the entire Lower Devonian interval. An intermediate depth fauna from Upper Pragian and Zlichovian dark carbonates is probably recognizable in northwestern Yukon, and termed the Strophochonetes-Proreticularia- receptaculitid Community. The widespread deep water graptolitic shales and carbonates contain a rich fauna of graptolites and relatively rare trilobite, sponge, and brachiopod faunas. 相似文献
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银缕梅物种濒危度的定量分析 总被引:14,自引:0,他引:14
采用二级模糊综合评判法进一步分析现存个体和居群数均极少的中国金缕梅科一新属种──银缕梅的物种濒危度。首先挑选对小种群绝灭有影响的随机干扰因素,建立了包括20个评价指标在内的因素集。然后通过对评价指标定量化和权分配一系列处理,并通过最初一、二层的综合评判,求得濒危度和保护等级,进而确定物种的濒危状态及其在省级和国家级的保护序次。研究结果表明,二级模糊综合评判的方法十分灵敏,可操作性强,它能比较准确地反映植物物种实际濒危状况。 相似文献
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HOWARD R. FELDMAN 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1980,13(1):27-46
Depositional environments of the Onondaga Limestone from central to southeastern New York are found to be normal, subtidal marine, due to the absence of characteristic supratidal or intertidal sedimentary features and the presence of a typical, diverse, marine level-bottom community framework. Post-mortem transport has not been extensive, as evidenced by low articulation ratios, lack of abraded valves, and complete ontogenetic gradations within species, which precludes large scale winnowing. Sedimentation rates appear to have been greatest in eastern New York where the Onondaga Limestone reaches a thickness almost three times that of the strata in central New York. Shaly beds in the central area represent periods of cessation of carbonate deposition rather than an influx of clastic material. Deposition terminated with the onset of deeper water characterized by a westerly advance of terrigenous sedimentation (the Marceilus Shale of the Hamilton Group). Nine brachiopod communities can be recognized in the Onondaga Limestone. There is a strong correlation between sediment-substrate and community type, reflecting the sedimentologic control of brachiopod community distribution. Sandy facies, cherty limestones and coral biostromes and bioherms are associated with inner-neritic deposition in Edgecliff time; argillaceous lime muds and lime sands are characteristic of mid-neritic deposition in Nedrow to Moorehouse time; and highly argillaceous lime muds are associated with outer-nerittc deposition in Seneca time. 相似文献
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Ubirajara Oliveira Antonio D. Brescovit Adalberto J. Santos 《Biodiversity and Conservation》2017,26(6):1481-1493
The knowledge on the geographical distribution of species is essential for building biogeographical and macroecological hypotheses. However, information on this regard is not distributed uniformly in space and usually come from biased sampling. The aim of this study is to quantify the influence of spatial distribution of sampling effort on the assessment of spider species richness in Brazil. We used a database of spider distribution records in Brazil, based on the taxonomic and biodiversity survey literature. The results show that the Atlantic Forest was better sampled and had the highest spider species richness among the Brazilian biomes. The Amazon, though having large collecting gaps and high concentration of records around major cities and rivers, showed the second highest number of species. The Pampa had a large number of records, but these are concentrated near a major city in the transition zone with the Atlantic Forest. The Cerrado, Caatinga and Pantanal had shown to be poorly sampled and, consequently, were among the lesser known biomes regarding the spider fauna. A linear regression analysis showed that the spider species richness in Brazil is strongly correlated to the number of records. However, we have identified areas potentially richest in species, which strongly deviate from the predicted by our analyses. Our results show that it is possible to access the spatial variation in species richness, as long as the variation in sampling effort is taken into account. 相似文献
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Xiu-Qin Chen 《Geobios》2004,37(5):575
The Early Devonian brachiopod genus Borealirhynchia was established by Su, 1976. Phylum Brachiopoda (Cambrian to Devonian). In: Paleontological Atlas of North China, Inner Mongolia Volume 1. Geological Publishing House Beijing, pp. 155-227 (in Chinese). It has not been previously described in detail, nor have transverse serial sections of the internal features of Borealirhynchia delerensis, the type species, been published. In this paper Borealirhynchia, along with a few species previously assigned to it, is analysed and discussed. Detailed transverse serial sections of the internal features of B.? lata Su, 1976, are provided, based on well-preserved specimens collected from the Lower Devonian strata of Dong Ujimqin Qi, northeastern Inner Mongolia. Borealirhynchia? gigantea Su, 1976 and Latonotoechia multicosta Su, 1976 are considered to be synonyms of B.? lata Su with the same external and internal characters present in all three species. Some Lower Devonian strata, in which Borealirhynchia was found and reported, from Dong Ujimqin Qi, northeastern Inner Mongolia, are fully described. 相似文献
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Storfer A 《Trends in ecology & evolution》1996,11(8):343-348
The measurement of genetic variation is often an important component of endangered species management programs. Each of several tools available to measure genetic diversity has positive and negative attributes. Quantitative genetic techniques have not received much attention in the conservation field, yet they are likely to reveal variation that is most closely associated with components of fitness. In addition, quantitative genetics may not be as logistically difficult for threatened populations as was once thought. Finally, quantitative genetic models provide a better outlook for conservation programs than single-locus models. 相似文献
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Integrating cost-benefits analysis and life cycle assessment of green roofs: a case study in Florida
AbstractMultiple environmental benefits can be achieved by using a green roof instead of conventional roofs. To better understand the LCA and cost-effectiveness of a green roof, a case study was performed. Two energy models, one with conventional white roof and the other with green roof, were created using eQUEST software to compare the influence of green roof on building energy consumption. The results indicated that the application of a green roof reduced annual space heating and cooling electricity consumption by 9500 kWh (2.2 kWh per square meter). The LCA shows that by using an extensive green roof in lieu of a conventional white roof the LCA measures at the product, construction, and end-of-life stages increased due to the use of additional layers. However, these increases are offset by the reduction of LCA measures at the use stage such that the overall environmental impacts of green roof is less than that of conventional roof. To find out the cost-effectiveness of green roof, a 50-year cost-benefits analysis was conducted. The analysis showed that the net savings of the green roof is negative compared to the white roof it replaced due to its higher initial cost and follow on maintenance cost. 相似文献
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The aim of our study was to identify major determinants of cardiovascular behavioural risk factors among subjects at increased risk of cardiovascular disease (CVD). The data for the qualitative analysis were obtained from the Croatian Adult Health Cohort Study (CroHort). The data analysis was based on the principles of Grounded Theory. We have generated the concept of an individual in a vicious circle of risky health behaviour, defined by the low level of motivation and unfavourable personal characteristics which in interaction with unsupportive social environment adversely influence one's health behaviour, leading to negative health outcomes that produce negative effects on one's motivation and social environment. Community nurses assessed that the respondents often weren't adequately recognising their CVD risk and were very reluctant about the change in their risky habits. Our results are supported by the quantitative analysis and are complementing other analyses of the cardiovascular risks within the CroHort study. 相似文献
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The existing set of methods for assessing toxicity of noxas, based on experiments with whole animals (subclinical toxicity, toxicokinetics, carcinogenity, teratogenity, neurotoxicologyetc.) does not provide much information about cellular and subcellular effects such compounds may exert. We suggest to complement the current methodology by combining a traditional morphological observation in an electron microscope with a spectroscopic method of electron microprobe X-ray analysis (or X-ray microanalysis). The latter makes it possible to measure concentrations of chemical elements in invidividual cells and organelles and effects of noxas can thus be assessed (i) at subcellular level, (ii) directlyin situ and (iii) quantitatively. Concentrations of biologically important elements such as phosphorus, sulfur or zinc were measured in individual organelles in both intact and noxa-treated tissues, thus offering a possibility of comparing the effects of various noxious species at subcellular level (with the noxa previously applied to whole tissue or animal). The suggested correlation of analytical and morphological information may also provide new insights into cellular targeting of noxas (and potentially also drugs) as some organelles appear to be much more susceptible to damage than others. Presented at the 4th Mini-Symposium on Biosorption and Microbial Degradation, Prague, Czech Republic, November 26–29, 1996. 相似文献
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Mirhoseini Seyed Hamed Koolivand Ali Bayani Mojtaba Sarlak Hamid Moradzadeh Rahmatollah Ghamari Farhad Sheykhan Adel 《Aerobiologia》2021,37(2):217-224
Aerobiologia - In the indoor environment of dental clinics, dental staff and patients are exposed to various types of infectious agents transported by aerosols and particles, generated during... 相似文献
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Background
Muscular weakness in myasthenia gravis (MG) is commonly assessed using Quantitative Myasthenia Gravis Score (QMG). More objective and quantitative measures may complement the use of clinical scales and might detect subclinical affection of muscles. We hypothesized that muscular weakness in patients with MG can be quantified with the non-invasive Quantitative Motor (Q-Motor) test for Grip Force Assessment (QGFA) and Involuntary Movement Assessment (QIMA) and that pathological findings correlate with disease severity as measured by QMG.Methods
This was a cross-sectional pilot study investigating patients with confirmed diagnosis of MG. Data was compared to healthy controls (HC). Subjects were asked to lift a device (250 and 500 g) equipped with electromagnetic sensors that measured grip force (GF) and three-dimensional changes in position and orientation. These were used to calculate the position index (PI) and orientation index (OI) as measures for involuntary movements due to muscular weakness.Results
Overall, 40 MG patients and 23 HC were included. PI and OI were significantly higher in MG patients for both weights in the dominant and non-dominant hand. Subgroup analysis revealed that patients with clinically ocular myasthenia gravis (OMG) also showed significantly higher values for PI and OI in both hands and for both weights. Disease severity correlates with QIMA performance in the non-dominant hand.Conclusion
Q-Motor tests and particularly QIMA may be useful objective tools for measuring motor impairment in MG and seem to detect subclinical generalized motor signs in patients with OMG. Q-Motor parameters might serve as sensitive endpoints for clinical trials in MG.17.
GEOFFREY FRYER 《Freshwater Biology》1987,17(1):177-189
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Sargent DJ Geibel M Hawkins JA Wilkinson MJ Battey NH Simpson DW 《Annals of botany》2004,94(6):787-796
BACKGROUND AND AIMS: The aims of this investigation were to highlight the qualitative and quantitative diversity apparent between nine diploid Fragaria species and produce interspecific populations segregating for a large number of morphological characters suitable for quantitative trait loci analysis. METHODS: A qualitative comparison of eight described diploid Fragaria species was performed and measurements were taken of 23 morphological traits from 19 accessions including eight described species and one previously undescribed species. A principal components analysis was performed on 14 mathematically unrelated traits from these accessions, which partitioned the species accessions into distinct morphological groups. Interspecific crosses were performed with accessions of species that displayed significant quantitative divergence and, from these, populations that should segregate for a range of quantitative traits were raised. KEY RESULTS: Significant differences between species were observed for all 23 morphological traits quantified and three distinct groups of species accessions were observed after the principal components analysis. Interspecific crosses were performed between these groups, and F2 and backcross populations were raised that should segregate for a range of morphological characters. In addition, the study highlighted a number of distinctive morphological characters in many of the species studied. CONCLUSIONS: Diploid Fragaria species are morphologically diverse, yet remain highly interfertile, making the group an ideal model for the study of the genetic basis of phenotypic differences between species through map-based investigation using quantitative trait loci. The segregating interspecific populations raised will be ideal for such investigations and could also provide insights into the nature and extent of genome evolution within this group. 相似文献
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《Palaeoworld》2016,25(4):600-615
Conodont biostratigraphical work was done at four sections recently found with occurrence of the rhynchonellide brachiopod genus, Dzieduszyckia Siemiradzki, in southern Guangxi and in the border area between Dushan County of Guizhou and Nandan County of Guangxi, South China. These sections represent two different types of facies, i.e., carbonate platform and intraplatform basin. The conodont analysis reveals that this genus occurs in the Upper triangularis Zone and the Middle crepida Zone at the Dazhai Section, through the Lower to Upper crepida zones at Dalong, and is restricted within the Upper rhomboidea Zone at the two intraplatform basin sections (Changtang and Duli). This result demonstrates that the occurrence of these peculiar rhynchonellide brachiopods in South China, regardless of the depositional environments, is within the Lower Famennian instead of the previously suggested Upper Famennian. Furthermore, this brachiopod genus in South China began to inhabit on the carbonate platform almost since the beginning of the Famennian and did not extend to the intraplatform basin facies until the late Early Famennian.Available biostratigraphic data indicate that during the Early and Middle Famennian, Dzieduszyckia is widely distributed not only in South China, but also throughout the world, such as Morocco and southern Ural.Observation on the new collections from the four studied sections reveals that the peculiar rhynchonellide brachiopods have a great morphological variation within each section. Significant differences existed among the collections from different sedimentary settings and localities, probably reflecting the environmental and geographic constraint on the morphology of Dzieduszyckia. Samples from different layers in the same section have nearly identical morphological variation, suggesting the temporal inheritance in morphology of the rhynchonellide brachiopod. 相似文献
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CLIFFORD A. CUFFEY ALBERT J. ROBB JOHN T. LEMBCKE ROGER J. CUFFEY 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1995,28(2):139-153
The in-life and post-mortem orientations of the Lower Devonian brachiopod Meristella atoka from the Haragan Formation (Lower Devonian; south-central Oklahoma) are inferred from the distribution of epizoic bryozoans and the orientations of base plates of epizoic corals. Three bryozoans, Cyphotrypa corrugata, Fistuliporella maynardi and Leioclema pulchellum, and one coral, Favosites conicus, are considered. Most zoaria that contact the commissure terminate at the commissurc, and a few zoaria terminate at growth lines. This suggests that the bryozoans were primarily life associates of Meristella atoka. Collectively, these three bryozoan species most extensively encrusted marginal sectors of the brachial valve and are very rare on the posteromedian sector (the umbo) of the pedicle valve. This distributional pattern indicates that the preferred living orientation of Meristella atoka was umbo-down (posteromedian sector of the pedicle valve resting on or buried in the substratum) with the commissure steeply inclined to the sediment water interface. Most coralla of Favosites conicus that contacted the commissure encrusted over the commissure. This indicates that Favosites conicus either preferentially encrusted Meristella atoka post-mortem or colonized living brachiopods but subsequently caused them to die. Furthermore, Favosites conicus most extensively encrusted anterior sectors of the brachial valve, especially the fold. The lateral and anterior orientations of the commissure with respect to the base plates (holothecae) of Favosites conicus indicates that the brachiopods were oriented approximately horizontal with respect to the base plates. This suggests that the preferred post-mortem orientation of Meristella atoka was resting nearly horizontally on the substratum. These data and interpretations confirm previously inferred in-life orientations of Meristella atoka and are consistent with post-mortem orientations hypothesized for elongate-oval athyrid brachiopods. □Brachiopoda, Athyridacea, Meristella atoka , palaeoecology, autecology, epizoans, bryozoans, corals, sedimentology, Lower Devonian, North America, Oklahoma. 相似文献