978 resultados para 361


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竹叶青蛇在全部受试物种中处于原始地位,分布于东北地区的蛇岛蝮、乌苏里蝮、黑眉蝮与浙江和陕西产的短尾蝮所组成的分枝与横断山区的高原蝮、雪山蝮聚集形成的分枝组成姐妹群,支持分布于中国境内的亚洲蝮属蛇种的两个起源及分化地的假说,同时探讨了蝮蛇的分类地位问题。

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通过比较一段357bp的细胞色素b的序列,分析了熊蜂属5亚属11种熊蜂系统发育关系。5亚属包括Bombus(5种)、Thoracobombus(3种)、Mendacibombus(1种)、Fervidobombus(1种)和Pyrobombus(1种)。该序列有65个单变异多态位点和71个简约信息多态位点,翻译成119个氨基酸序列后有45个氨基酸变异位点。根据P-距离构建的邻接树(NJ tree)和最大简约树(MP tree)都显示同样的结果:Mendacibombus(B. avinovielllus)分化最早;Fervidobombus(B. pensylvanicus)次之;Pyrobombus(B. impatiens)和Bombus形成姊妹群;Bombus亚属是单系群,其中B. ignitus在所研究的5个种中分化最早。

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A total of 361 caudal fin samples were collected from adult A. stellatus specimens caught in the north Caspian Sea, including specimens from Kazakhstan (Ural River), Russia (Volga River), Azerbaijan (Kura River), specimens caught in the south Caspian Sea including specimens from Fishery Zone 1 (from Astara to Anzali), Fishery Zone 2 (from Anzali to Ramsar), Fishery Zone 3 (from Nowshahr to Babolsar), Fishery Zone 4 (from Miyankaleh to Gomishan) as well as from specimens caught in Turkmenistan (all specimens were collected during the sturgeon stock assessment survey). About 2 g of fin tissue was removed from each caudal fin sample, stored in 96% ethyl alcohol and transferred to the genetic laboratory of the International Sturgeon Research Institute. Genomic DNA was extracted using phenol-chloroform method. The quality and quantity of DNA was assessed using 1% Agarose gel electrophoresis and Polymerase Chain Reaction (PCR) was conducted on the target DNA using 15 paired microsatellite primer. PCR products were electrophoresed on polyacrylamide gels (6%) that were stained using silver nitrate. Electrophoretic patterns and DNA bands were analyzed with BioCapt software. Allele count and frequency, genetic diversity, expected heterozygosity and observed heterozygosity allele number, and the effective allele number, genetic similarity and genetic distance, FST and RST were calculated. The Hardy Wienberg Equilibrium based on X2 and Analysis of Molecular Variance (AMOVA) at 10% confidence level was calculated using the Gene Alex software. Dendrogram for genetic distances and identities were calculated using TFPGA program for any level of the hierarchy. It is evident from the results obtained that the 15 paired primers studied, polymorphism was observed in 10 pairs in 12 loci, while one locus did not produce DNA bands. Mean allele number was 13.6. Mean observed and expected heterozygosity was 0.86 and 0.642, respectively. It was also seen that specimens from all regions were not in Hardy Wienberg Equilibrium in most of the loci (P≤0.001). Highest Fst (0.063) was observed when comparing specimens from Fishery Zone 2 and Fishery Zone 4 (Nm=3.7) and lowest FST (0.028) was observed when comparing specimens from the Volga River and those from the Ural River (8.7). Significant differences (P<0.01) were observed between RST recorded in the specimens studied. Highest genetic distance (0.604) and lowest genetic resemblance (0.547) were observed between specimens from Fishery zones 2 and 4. Lowest genetic distance (0.311) and highest genetic resemblance (0.733) was observed between specimens from Turkmenistan and specimens from Fishery zone 1. Based on the genetic dendrogeram tree derived by applying UPGMA algorithm, A. stellatus specimens from Fishery zone 2 or in other words specimens from the Sepidrud River belong to one cluster which divides into two clusters, one of which includes specimens from Fishery zones 1, 3 and 4 and specimens from Turkmenistan while the other cluster includes specimens from Ural, Volga and Kura Rivers. It is thus evident that the main population of this species belongs to the Sepidrud River. Results obtained from the present study show that at least eight different populations of A. stellatus are found in the north and south Caspian Sea, four of which are known populations including the Ural River population, the Volga River population, the Kura River population and the Sepidrud River populations. The four other populations identified belonging to Fishery zones 1, 3, and 4 and to Turkmenistan are most probably late or early spawners of the spring run and autumn run of each of the major rivers mentioned. Specific markers were also identified for each of the populations identified. The Ural River population can be identified using primers Spl-68, 54b and Spl-104, 163 170, 173, the Volga River population can be identified using primers LS-54b and Spl-104, 170, 173 113a and similarly the population from the Kura River can be identified using primers LS-34, 54b and Spl-163, 173 and that from the Sepidrud River can be identified using primers LS-19, 34, 54b and Spl-105, 113b. This study gives evidence of the presence of different populations of this species and calls for serious measures to be taken to protect the genetic stocks of these populations. Considering that the population of A. stellatus in Fishery zone 2 is an independent population of the Sepidrud River in the Gilan Province, the catch of these fishes in the region needs to be controlled and regulated in order to restore the declining stocks of this species.

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该文基于外部形态、毛色、头骨特征和地理分布对藏酋猴(Macaca thibetana)进行了分类整理, 认为藏酋猴在不同地理区域之间的差异已达到了亚种水平, 可分为4个亚种(包括两新亚种); M. thibetana thibetana, M. thibetana pullus, M.thibetana huangshanensis subsp.nov.和M. thibetana guizhouensis subsp. nov。

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2005年2月26日和3月1日在云南省昭通大山包黑颈鹤国家级自然保护区,分别为4只越冬黑颈鹤佩戴卫星信号发射器(PTTs),跟踪研究其迁徙路线和迁徙停歇地.2005年春季迁徙中,有2只跟踪黑颈鹤到达繁殖地,其中1只黑颈鹤在2005年11月和2006年3月分别完成从繁殖地返回越冬地和从越冬地再次到达繁殖地的迁徙过程.2只春季迁徙黑颈鹤的迁徙路线大致相同--沿着长江上游金沙江、大渡河一直向北到达黄河上游白河及黑河沿岸若尔盖湿地内.春季迁徙过程中,途中停歇3-4次,总迁徙距离是674-713 km,迁徙全程所用时间3-4天.秋季迁徙全程所用时间8天.在4个PTTs工作期间,共确定有13个黑颈鹤迁徙停歇地,其中11个停歇地在河流滩地;其他2个停歇地在高山湖泊附近.总体上,黑颈鹤一般选择海拔在1 900 m以上湖泊、河流等湿地内,距离耕地较近且人、畜干扰较少的栖息地停歇.

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白马蝠蛾雌性生殖系统与鳞翅目其他昆虫不同: 无粘液腺器官; 成虫产卵行为特殊, 卵散产, 产后有用尾和足扫土盖卵的习性; 成虫交配授精以精包方式进行。交配除提供雌蛾精子外, 还能刺激产卵。最适宜成虫交配与产卵的温度为12.5—19.0℃, 相对湿度75—90%。图2表3参5

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报道云南盘ju属鱼类4新种: 多鳞盘juD. polylepis、长鳔盘juD. macrophysallidos、长体盘juD. elongatus和短鳔盘juD. brachyphysallidos。全模标本存中国科学院昆明动物研究所。图4参9

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The destruction mechanism in large area IGCTs (Integrated Gate Commutated Thyristors) under inductive switching conditions is analyzed in detail. The three-dimensional nature of the turn-off process in a 91mm diameter wafer is simulated with a two-dimensional representation. Simulation results show that the final destruction is caused by the uneven dynamic avalanche current distribution across the wafer. © 2011 IEEE.