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201.
202.
研究了西伯利亚西部几个地点钻孔侏罗纪岩芯样中的植物微体化石。在有关组合中,Lycopodium sp., Coniopteris spp.和Gleicheniidites sp.的孢子少,Klukiasporites sp.极少;代表性花为有Pinus exilioides,P.disulgaus,sciadopites sp.和Classopollis;微体浮游植物占优势,例如Crassisphaera sp.,Tasmanites sp.,Pterospermopsis eurypteris. P.harti和Cymatiosphaera sp.颇丰富,有时出现Pareodinia sp.和Trichodinium sp.。虽然各个组合中孢子、花粉、微体浮游植物在含量上有变化,但总的组成在西伯利亚西部不同地区尚稳定,此等微化石的颜色或有变化,它们(特别是微体浮游植物)可用来检测沉积有机质受热变质的成熟度级别。  相似文献   
203.
周围神经43kD蛋白免疫化学研究   总被引:3,自引:1,他引:2  
目的:制图周围神经43kD蛋白单克隆抗体,并检测该蛋白在正常及损伤坐骨神经中的表达,方法:实验用SDS-聚丙烯酰胺胺凝胶电泳系统,从周围神经中分离回收43kD蛋白作为抗原,免疫BALB/c小鼠,通过杂交瘤技术和点膜印迹法检测,获得分泌识别43kD蛋白的单克隆抗体的杂交瘤细胞株,以Westernblot方法检测单克隆抗体的特异性,并检测43kD蛋白在正常坐骨神经及损伤坐骨神经远侧端中的表达。结果:经检测获得了识别43kD蛋白的单克隆抗体,Westernblot显示在正常大鼠坐骨神经与损伤后2周的坐骨神经远侧端组织电泳图谱43kD处均出现特异的阳性反应条带,在损伤神经中43kD蛋白阳性反应产物着色较深。结论:43kD蛋白具有独特的免疫化学特性,在正常与损伤坐骨神经中的有表达,在损伤坐骨神经中表达更强。  相似文献   
204.
 在青藏高原的西北部,喜马拉雅山、喀喇昆仑山和昆仑山汇聚成一个高大山系组。中国-巴基斯坦公路横跨这个山系组,沿线植被的组成及分布显示出极其明显的地域分异:西昆仑山和喀喇昆仑山以荒漠为主,西北喜马拉雅山以山地森林为主;西昆仑山前平原上是暖温带灌木、半灌木荒漠,西北喜马拉雅山前印度河平原上是亚热带稀树草原;山系组腹地谷坡明显较外部山坡干燥,西昆仑山东北坡有完整的山地草原和高山草甸带,以及断续的山地云杉(Picea)和刺柏(Juniperus)疏林灌丛,而西南坡山地荒漠海拔高达3600~4000 m,草原和草甸带  相似文献   
205.
Difficulties in controlling outbreaks of Western flower thrips, Frankliniella occidentalis, have obstructed the widespread adoption of biological control in many ornamental crops. The efficacy of the predatory mite, Neoseiulus cucumeris, in controlling F. occidentalis on two cultivars of cyclamen was tested in glasshouse experiments. The establishment and development of F. occidentalis populations was compared in three treatment introductions of N. cucumeris (50, 200 and 350 mites m -2 per week) and an untreated control. F. occidentalis were sampled in the flowers over eight weeks and counted into different life stages. No differences were observed between the two cultivars. All treatments with the predator resulted in a decline in numbers of F. occidentalis compared to the untreated control. Although the proportion of first instar F. occidentalis was similar in all treatments, the level of control varied with the number of N. cucumeris introduced. Lower populations of F. occidentalis, combined with a more rapid decline in their numbers, were observed at the 200 and 350 mites m -2 rates. Numbers of F. occidentalis remained low in the 350 N. cucumeris m -2 rate and the proportion of second instar F. occidentalis in the samples was consistently lower than in the other treatments. Trap counts of adult F. occidentalis were strongly correlated with the numbers of both adult and total F. occidentalis in flower samples. High inoculative releases of N. cucumeris early in the flowering cycle followed by frequent low introductions of predators should provide a strong basis for preventative control of F. occidentalis and other thrips species on cyclamen.  相似文献   
206.
In order to determine which species of geophilic dermatophytes were present in Western Australian soils 299 samples were investigated. These samples were collected from a range of locations, 208 from towns throughout the state and 91 samples from the Perth Metropolitan area.Most samples were collected from areas frequented by people and animals, such as home gardens, parks and animal yards.Of the total 299 soils, 271 (90.6 %) yielded keratinophilic fungi. A total of 181 dermatophytes were isolated, and there were 205 isolations of other keratinophilic fungi. Microsporum gypseum (30.7 %) was the most prevalent dermatophyte recovered from soil followed byMicrosporum cookei (21.7 %) and thenTrichophyton ajelloi (8.0 %). No other dermatophytes were recovered.Chrysosporium indicum was the most common of all the keratinophilic fungi and was isolated from 50.1 % of the samples. Mixed growth was obtained from 33.5 % of the soil samples.  相似文献   
207.
Synopsis Ninety six fish belonging to 19 species were taken by deep water line fishing off Aldabra. Analysis of the results shows how various factors such as hooking time changed with depth. The change of bottom temperature with depth was examined. The zone between 100 m and 150 m was found to have considerable temperature variations. The distribution of some serranids and lutjanids appeared to be stratified though there was usually overlap in the range of adjacent species. The results are compared with previous line-fishing off the South coast of Aldabra from deeper water and other areas of the western Indian Ocean.  相似文献   
208.
The Lophiodontidae is an emblematic and well-documented Eocene family of perissodactyls from Western Europe. However, after more than a century and a half of studies, lophiodontids still display a complex systematics associated with blurry intraspecific variation and a poorly known early radiation. The locality of La Borie, located near the city of Toulouse, France, has yielded numerous remains of Eolophiodon laboriense. This abundance of remains allows for the first time the study of the intraspecific variation of a basal lophiodontid. The variation has been investigated for dental and cranio-mandibular characters, notably dental polymorphism, size variation and sexual dimorphism. The intraspecific variation of E. laboriense is high with more than 20 polymorphic characters of the dentition, including many additional crests and conules. This dental polymorphism is similar to the one observed in the Bartonian lophiodontid Lophiodon lautricense. E. laboriense also displays an important degree of sexual dimorphism, with male specimens having broader and longer mandibles with larger canines than females. Despite this high intraspecific variation, the low size variation of teeth and the consistency of diagnostic characters strengthen the validity of the genus Eolophiodon and does not impact the previous lophiodontid phylogeny.  相似文献   
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210.
Connectivity for large mammals across human-altered landscapes results from movement by individuals that can be described via nested spatial scales as linkages (or zones or areas) with compatible land use types, constrictions that repeatedly funnel movement (as corridors) or impede it (as barriers), and the specific paths (or routes) across completely anthropogenic features (such as highways). Mitigation to facilitate animal movement through such landscapes requires similar attention to spatial scale, particularly when they involve complex topography, diverse types of human land use, and transportation infrastructure. We modeled connectivity for Asian elephant (Elephas maximus) and gaur (Bos gaurus) in the Shencottah Gap, a multiple-use region separating two tiger reserves in the Western Ghats, India. Using 840 km of surveys for animal signs within a region of 621 km2, we modeled landscape linkages via resource selection functions integrated across two spatial resolutions, and then potential dispersal corridors within these linkages using circuit theoretical models. Within these corridors, we further identified potential small-scale movement paths across a busy transportation route via least-cost paths and evaluated their viability. Both elephants and gaur avoided human-dominated habitat, resulting in broken connectivity across the Shencottah Gap. Predicted corridor locations were sensitive to analysis resolution, and corridors derived from scale-integrated habitat models correlated best with habitat quality. Less than 1% of elephant and gaur detections occurred in habitat that was poorer in quality than the lowest-quality component of the movement path across the transportation route, suggesting that connectivity will require habitat improvement. Only 28% of dispersal corridor area and 5% of movement path length overlapped with the upper 50% quantile of the landscape linkage; thus, jointly modeling these three components enabled a more nuanced evaluation of connectivity than any of them in isolation.  相似文献   
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