991 resultados para 7140-232


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The excitation as well as relaxation dynamics of dye-doped nematic liquid crystal cells has been explored both experimentally and theoretically. Overshoots in the build up of the probe signal diffracted from gratings written onto dye-doped liquid crystal systems have often been observed. The overshoot behaviour makes the accurate measurement of nonlinear optical (NLO) response magnitude difficult and ambiguous. Moreover, it complicates the understanding of the dynamics and the physics of the NLO processes. On the basis of the system with trans-cis isomerisation as a mechanism of the NLO effect the quantitative model has been built to describe the experimental results which we observe. The two unknown material parameters: diffusion coefficient and cis species lifetime are calculated from the relaxation data. A quantitative model of the signal build-up uses these parameters. The calculated dynamic behaviour based on this model correlates very well with the experimental data. The model is used to predict the performance of the system with various dopant diffusion properties.

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We investigated the distribution of Y-chromosome haplotype using 19 Y-SNPs in Han Chinese populations from 22 provinces of China. Our data indicate distinctive patterns of Y chromosome between southern and northern Han Chinese populations. The southern po

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This Chapter presents a vision-based system for touch-free interaction with a display at a distance. A single camera is fixed on top of the screen and is pointing towards the user. An attention mechanism allows the user to start the interaction and control a screen pointer by moving their hand in a fist pose directed at the camera. On-screen items can be chosen by a selection mechanism. Current sample applications include browsing video collections as well as viewing a gallery of 3D objects, which the user can rotate with their hand motion. We have included an up-to-date review of hand tracking methods, and comment on the merits and shortcomings of previous approaches. The proposed tracker uses multiple cues, appearance, color, and motion, for robustness. As the space of possible observation models is generally too large for exhaustive online search, we select models that are suitable for the particular tracking task at hand. During a training stage, various off-the-shelf trackers are evaluated. From this data differentmethods of fusing them online are investigated, including parallel and cascaded tracker evaluation. For the case of fist tracking, combining a small number of observers in a cascade results in an efficient algorithm that is used in our gesture interface. The system has been on public display at conferences where over a hundred users have engaged with it. © 2010 Springer-Verlag Berlin Heidelberg.

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Although spermatozoa from several species of nonhuman primates have been cryopreserved, there has been no report of success with rhesus macaque spermatozoa as judged by functional assays. Two Tris-egg yolk freezing media. TEST and TTE. which have: been successfully used for cynomolgus macaque (Macaca fascicularis) spermatozoa, were compared for cryopreservation of spermatozoa From four rhesus macaques (Macaca mulatta). The postthaw motility (percentage and duration) of spermatozoa cryopreserved in TTE was much higher than that for spermatozoa cryopreserved in TEST. The function of sperm cryopreserved in TTE was evaluated by in vitro fertilization or oocytes collected from gonadotropin-stimulated prepubertal rhesus macaques. Of the inseminated oocytes. 82 +/- 13% were fertilized and 63 +/- 22 and 39 +/- 21% of the resulting zygotes developed into morulae and blastocysts. respectively. These results indicate that rhesus macaque spermatozoa can be effectively cryopreserved in TTE medium. This finding will facilitate the application of in vivo and in vitro assisted reproductive technologies in this species. (C) 2001 Academic Press.

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报道了锦蛇属团花锦蛇( E. davidi) 、绿锦蛇( E. prasina) 和三索锦蛇( E. radiata) 3 个种的核型和Ag - NORs ,团花锦蛇的核型2 n = 36 (8V + 6sV + 2I + 20M) ;绿锦蛇的核型2 n = 36 (7V + 7sV + 2I + 20m) ,三索锦蛇的 核型2 n = 40 (6V + 3sV + 2sI + 5I + 24m) ; ①团花锦蛇和绿锦蛇的染色体数目和结构与此属大多数种的相似, ; ② 此属种类的性染色体为ZW型,绿锦蛇的性染色体为第4 对大染色体,三索锦蛇的为第5 对大染色体,团花锦蛇 由于为雄性,未见染色体异型. ③Ag - NORs 在数目及在染色体上的位置均不相同,团花锦蛇的NORs 在第9 对 染色体上,数目为2 个;绿锦蛇的NORs 在第5 对染色体上,数目为4 个;三索锦蛇的NORs 在第4 对大染色体上, 数目为4 个; ④我们发现三索锦蛇较为特殊,其染色体数目、形态、性染色体的位置和形态及Ag - NORs 均与其 它种类不同. 可能的原因是此物种在核型演化过程中发生过染色体断裂和重排事件,提示三索锦蛇可能是一个 特化的类群. ⑤锦蛇属的种类可分为包括三索锦蛇为特殊的一组的4 个组. 图版1 表2 参18

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本研究采用10种限制性内切酶(AvaⅠ,BamHⅠ,BglⅡ,EcoRⅠ,EcoRⅤ,HindⅢHpaI,PstI,PvuⅡ and SalI)对中国南方四省──云南、贵州、广东和海南省的11个地方黄牛品种和1个培育牛品种共154份样品进行了线粒体DNA限制性内切酶片段长度多态性分析(mtDNARFLP)。结果发现,除EcoRⅠ外其余9种酶均表现出多态性。共检测到23种限制性态型,可以归结为5种单倍型。利用“UPGMA”方法构建了单倍型间的聚类树。研究表明,单传型Ⅰ和Ⅱ分别与瘤牛(Bos indicus)和普通牛(Bostaurus)的单倍型一致,瘤牛和普通牛是中国南方黄牛的2个重要起源,其中瘤牛在中国南方黄牛形成过程中的贡献较普通牛大。单格型Ill与牦牛的互型一致,仅在云南迪庆黄牛中检测到,提示从牦牛(Bo.ggfu;;。ie。s)到迪庆黄牛可能存在着mtDNA渐渗现象。IV型为首次报道,为云南省德宏黄牛所特有,推测可能是来自除印度瘤牛外的另一支瘤牛的独立驯化事件。单倍型1和IV的分歧时间大约是在26880—535000年以前,比黄牛的驯化时间10000年要早许多。中国南方黄牛的mtDNA变异研究──起源及...

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To study the mitochondrial DNA (mtDNA) polymorphisms in a total of 232 individuals from five ethnic populations (Daur, n=45; Ewenki, n=47; Korean, n=48; Mongolian, n=48; Oroqen, n=44) in northern China, we analyzed the control region sequences and typed for a number of characteristic mutations in coding regions (especially the region 14576-16047), by direct sequencing or restriction-fragment-length-polymorphism (RFLP) analysis. With the exception of 14 individuals belonging to the European-specific haplogroups R2, H, J, and T, the mtDNAs considered could be assigned into the East Asian-specific haplogroups described recently. The polymorphisms in cytochrome b sequence were found to be very informative for defining or supporting the haplogroups status of East Asian mtDNAs in addition to the reported regions 10171-10659 and 14055-14590 in our previous study. The haplogroup distribution frequencies varied in the five ethnic populations, but in general they all harbored a large amount of north-prevalent haplogroups, such as D, G, C, and Z, and thus were in agreement with their ethnohistory of northern origin. The two populations (Ewenki and Oroqen) with small population census also show concordant features in their matrilineal genetic structures, with lower genetic diversities observed.

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用形态解剖学的方法,观察研究和描述了云南冬虫夏草优势寄主昆虫白马蝠蛾5龄幼虫的前肠、中肠、后肠及唾腺的构造。图4

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其它部委、高等院校基金

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The Yunnan snub-nosed monkey (Rhinopithecus bieti) is one of the most endangered species in the world, and it is endemic to China. According to our knowledge, there was no information on reproduction for this species. The present study was designed to und

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This survay has been done from Januray 2000 till May 2002 in Khouzestan costal waters. Four species of grouper were identified from which orange spotted grouper (Epinephelus coioides) was the dominant species. For studing environmental parameters and reproductive biology, age, growth parameters and mortality rate samples were collected by fishing ship. Samples were taken montly in 4 days by fishing traps and trawls. In addition, some samples were obtained from Khozestan fish landing centres. Environmental factors such as PH, 02, salinity, water temperature and depth of traping areas, were measured. To identify species, morphometric characteries of 452 individal fishes were measured. Stomach contents of 394 fish were has survaid, from which stomach of 226 fish, and 168 fish had empty stomachs. Percentage of empty stomachs (cv) in males was more than females. Food items found in 73 percent of stomach were crab (11%), shrimps (8.8%) , squids (3.9%), gastropods (17%) and bivalves (0.4%). Feeding intensity in year classes did not obay logic trends The importance relatively indicator (I.R.I) were 81, 9.9, 4, 1.5 and 0.3 percent for fish, crab, shrimp, squid, gastropod and bivalve respectively. For age determination, sagita otoliths of 450 fish were taken and countable sections were obtained from 425 specimens. Relative frequency distribution of opaque and transparent rings showed that each opaque growth ring generates once a year from November to September. It seemed that generation of opaque rings is affected by temperature and photoperiod changes. Correlation between length and age was calculated using Von Bertalanffy's least square method. Following equasion was obtaind: L(t) : 122.27 (1 e 0.146 (t+0.482)) Growth parameters were determined through by Ford Walford equasion and Response Surface and Shepherd subcommands in Elefan program and L00 and K amounts were have determined. Correlation between length and age of 635 fish was determined by gender . Length and age correlation was calculated by exponential model and between total length and standard length by straghit line model. Correlation between age and weight of sagita was calculated by total length and age. The most Correlation was between sagita weight and fish age (r=0.876). Total mortality rate (z) was estimated by Length Converthed Method , Jones and Vanzaling and Powel Wetherall. Total mortality rate was z=0.39. Natural mortality rate, using Pauly method was calculated M=0.32. Fishing mortality (F) was 0.08. Gonads of 425 fishes were surveid within 18 month, from which 363 were female, 46 were male and 16 were sex reversing individuals .Total length of females varied from 26 to 95.5 centimeters while males length varied from 56.5 to 107 centimeters. Sex reversing individuals had a length of 47.5 centimeters, when two years old and 62.5 centimeters at age of 3 years. From the mentioned 425 fish, 401 individuals were matured, containing 339 females and 62 males, 5.47 females against each male. Montly changes of Gonadosomatic Index (GSI) by total body weight and standard length and total body length showed that this index increases from march to May and maximum increase was in May . This experiment was adapted in spawning season. Potential, relative, and absoulate fecundity was estimated by counting eggs in three samples. Total amount of traped fish using special traps was 16182.18 kg from which Epinephelus coioides provided catching 15353.43 kg of it (91.27 %) and By catch was 141.18 kg (8.24 %). Total average CPUE for whole catch was 123.33 kg/day/vessel. Total amount of catch was estimated 232.04 tons, considering CPUE of total catch and total Khuzestan trap ships effort.

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2007年9~11月和2008年4~5月,对云南省丽江玉龙雪山自然保护区的鸟类资源进行了调查,共记录鸟类184种,结合中国科学院昆明动物研究所鸟类标本室收藏的该地区标本和文献记录的种类,保护区内共记录鸟类330种(另13亚种),隶属47科(另4亚科),18目,占云南省所录鸟类种数848种的38.92%,全国鸟类种数1329种的24.83%。其中国家一级保护物种1种,二级保护物种29种。黑眉长尾山雀Aegithalos iouschistos和大嘴乌鸦Corvus macrorhynchos为保护区内的优势种类。保护区记录的鸟类有留鸟230种和亚种,占所录鸟类种和亚种数的67.05%。区系成分以东洋界物种为主,有182种,占繁殖鸟类总种数的66.42%。亚区级区系分析表明保护区的鸟类以西南山地亚区的种类为主。结合该区鸟类生境分布的特点,提出云南松高山松林、针阔混交林和寒温性暗针叶林的保护是保护工作的重点。