947 resultados para 49-409


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Group IIA phospholipase A(2) (PLA(2)) are major components in Viperidae/Crotalidae venom. In the present study, a novel PLA(2) named promutoxin with Arg at the site 49 has been purified from the venom of Protobothrops muerosquamatus by chromatography. It

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We investigated the phylogenetic relationships among most Chinese species of lizards in the genus Phrynocephalus (118 individuals, collected from 56 populations of 14 well-defined species and several unidentified specimens) using four mitochondrial gene fragments (12S rRNA, 16S rRNA, cytochrome b, and ND4-tRNA(LEU)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), neighbor-joining (NJ), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset (49 haplotypes including outgroups for 2058 bp in total). The maximum-parsimony analysis resulted in 24 equally parsimonious trees, and their strict consensus tree shows that there are two major clades representing the Chinese Phrynocephalus species: the viviparous group (Clade A) and the oviparous group (Clade B). The trees derived from Bayesian, ML. and NJ analyses were topologically identical to the MP analysis except for the position of P. mystaceus. All analyses left the nodes for the oviparous group, the most basal clade within the oviparous group, and P. mystaceus unresolved. The phylogenies further suggest that the monophyly of the viviparous species may have resulted from vicariance, while recent dispersal may have been important in generating the pattern of variation among the oviparous species. (C) 2003 Elsevier Science (USA). All rights reserved.

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Temporal and spatial variations of the phytoplankton assemblage in Lake Chaohu, a large shallow eutrophic lake in China, were studied from September 2002 to August 2003. A total of 191 phytoplankton species was identified, among which Chlorophytes (101) ranked the first, followed by Cyanophytes (46) and Bacillariophytes (28). On average over the entire lake, the maximum total algal biomass appeared in June (19.70 mg/L) with a minimum (5.05 mg/ L) in November. In terms of annual mean biomass, cyanobacteria contributed 45.43% to total algal biomass, followed by Chlorophytes (27.14%), and Bacillariophytes (20.6%). When nitrate (NO3-N) and ammonium (NH4-N) concentrations dropped in spring, fixing-nitrogen cyanobacterium (Anabaena) developed quickly and ranked the first in terms of biomass in summer. It is likely that dominance of zooplanktivorous fish and small crustacean zooplankton favored the development of the inedible filamentous or colony forming cyanobacteria. The persistent dominance of cyanobacteria throughout all seasons may indicate a new tendency of the response of phytoplankton to eutrophication in Lake Chaohu.

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于2010-11-23批量导入

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采用测量反射谱方法确定了低压金属有机化合物气相外延生长的GaAs衬底匹配(Al_xGa_(1-x))_(0.51)In_(0.49)P外延材料的折射率。实验中测量的反射谱波长范围为05-2.5μm。在拟合实验数据过程中采用了单振子模型。折射率数据用于分析应变量子阱GaInP/AlGaInP可见光激光二极管波导,计算出的器件远场图与实验数据吻合很好。

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本论文研究了胶洲湾、东海和渤海的蓝细菌(Synechococcus)、生物量、异养细菌生物量和生产力的生态学特点。并在汇泉湾、渤海和东海用分极增减法对海洋蓝细菌在微型食物环(the microbial loop)中的作用进行了初步研究。在以上海区调查研究的时间如下:胶州湾:1993年2月、5月、9月11月,1996年5月、1999年3月、5月和12月。汇泉湾:1996年4月至1998年4月。东海:1997年2-3月,1998年7月。渤海1998年9-10月,1999年4-5月。研究结果如下:胶州湾:蓝细菌生物量的变化范围是11.4-0.03 mgC/m~3,季节变化是夏季>秋季和春季>冬季。其水平分布是除夏季蓝细菌生物量是沿岸浅水区向湾外递减外,其它三季(春、秋和冬季)是由湾外向湾内至沿岸浅水区递减。蓝细菌生物量与海水温度周年变化正相关,与季节海水温度的关系是秋、冬季分布变化一致,春、夏季分布变化相反。海水温度是影响胶州湾蓝细菌生物量分布变化的主要原因。异养细菌生物量和生产力的变化范围分别是29.8-1.62 mgC/m~3; 129.12-1.92 mgC/m~3.d。季节变化都是夏季>秋季、春季>冬季。夏季的异养细菌生物量和生产力水平分布趋势与蓝细菌生物量的分布变化相同。海水温度对异养细菌生产力的影响较对异养细菌生物量的影响大。异养细菌生产力相比(BP:PP)的变化在0.58-0.02之间,季节分布变化是夏季>秋季、春季>冬季。夏季表层的BP:PP由沿岸浅水区向湾心、湾口和湾外递减。东海:蓝细菌生物量的变化范围是46.72-0.011 mgC/m~3,夏季高平均是23.59 mgC/m~3,冬季低平均是3.61 mgC/m~3。冬季蓝细菌生物量的水平分布明显受黑潮的影响,在表面和20米层是由东南向西北方向递减。其垂直分布是冬季表层和20米层>底层,夏季是20米层>表层>底层;在连续站冬111站和410站变化都是中层>底层>表层。异养细菌生物量和生产力的变化范围分别是17.2-4.4 mgC/m~3(1997.2);376.8-7.2 mgC/m~3.d。异养细菌生产力夏季高平均是35.1 mgC/m~3.d。异养细菌生物量的水平分布是由沿岸向外海递增(1997.2),异养细菌生产力的水平分布是冬季异养细菌生产力在32度断面有由沿岸向外递减趋势,PN断面的变化与冬季相似。垂直分布,冬季和夏季的异养细菌生产力的垂直变化在2断面是底层大于表面,PN断面则是表层大于底层,32度断面大多断站是底层大于表层。在连续站冬季111站异养细菌生产力的变化是底层>中层>表层,409站的变化是中层>底层>表层,夏季111站和410站都是中>底层>表层。异养细菌生物量(1997.2)表层分布变化与海水温度分布变化相似,底层变化相反。异养细菌生产力与初级生产力相比(BP:PP),冬季在0.04-0.30之间,平均为0.17;夏季在0.20-0.43之间平均0.32。冬季在长江口附近BP:PP有一个高值区是0.30,夏季在111站附近有一个高值区是0.43。从连续站111站和409’站观测发现底层的BP:PP明显高于表层。渤海:蓝细菌生物量秋季(16.6-0.37 mgC/m~3)比春季(0.44-0.015 mgC/m~3)高。其秋季的水平分布与海水盐度水平分布相同,与海水温度水平分布相反。异养细菌生产力秋季(189-62.2 mgC/m~3.d)与春季(193.2-49.8 mgC/m~3.d)相当。但秋季捕层BP普遍小于底层,而春季是表层普遍大于底层。根据颗粒分级培养实验结果,海洋蓝图细菌在微型食物环中的作用如下:在汇泉湾的春季和秋季蓝细菌可能主要被小型浮游动物(microzooplankton 20-200 μm)捕食。在渤海的春季和秋季也是同样结果。但在东海夏季的111站和410站附近(东海大陆架中部)微型浮游动物(nanozooplankton 2-20 μm)对蓝细菌的捕食压力明显。

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瑶岗仙钨矿床位于湘东南后加里东隆起和湘、桂、粤北海西—印支坳陷带的交接部位,是南岭地区最典型的石英脉型钨矿床之一。为了深入研究瑶岗仙钨矿的成矿机制,本文在野外地质工作基础上,选取有代表性的样品,进行了氦、氩同位素以及碳、氧、硫稳定同位素研究,探讨了矿床成矿流体的来源,成岩成矿的关系,并初步讨论了矿床的成因模式。论文主要获得以下认识: (1)对瑶岗仙矿区不同硫化物中流体包裹体的氦、氩同位素系统测定表明,该矿床毒砂流体包裹体中3He/4He比值为0.58~2.60 Ra;黄铁矿和黄铜矿流体包裹体中3He/4He比值分别为0.41~1.26 Ra 和0.37~0.43 Ra,黑钨矿流体包裹体中氦同位素组成相对变化较大,其3He/4He比值为0.05~0.49 Ra,这些He同位素组成均明显高于地壳相应值;毒砂流体包裹体中的40Ar/36Ar变化范围在309.94~454.39;黄铁矿流体包裹体中的40Ar/36Ar变化范围在409.12~1822.31;黄铜矿和黑钨矿流体包裹体中的40Ar/36Ar变化范围分别为673~886和325~903,明显高于饱和大气雨水的40Ar/36Ar值。上述氦、氩同位素组成揭示瑶岗仙钨矿床中的成矿流体具有壳、幔两端元混合的特点。结合区域地质构造演化和成矿年代学的研究成果,本文认为瑶岗仙钨矿床的成矿流体是瑶岗仙花岗岩浆分异出的含有地幔He的岩浆流体与大气成因地下水二端元混合的产物。 (2)层解石和方解石的C、O同位素显示,该矿方解石的13CPDB和18OSMOW的变化范围为-2.2‰~ -7.0‰(均值为-4.8‰)和5.6‰~14.4‰(均值为11.3‰);层解石的13CPDB和18OSMOW的变化范围为-5.5‰~ -6.3‰(均值为-5.8‰)和12.7‰~14.3‰(均值为13.8‰);该矿方解石、层解石的C、O同位素组成与赣南西华山钨矿床非常类似。这些C、O同位素指示,该矿的成矿流体主要来自岩浆水,后期有少量大气降水的参与。 (3)对瑶岗仙矿区不同硫化物的硫同位素研究表明,该矿硫化物δ34S值的变化范围很窄,为-2.0‰~1.5‰之间,且具有明显的塔式分布。这些特征暗示,该矿的硫来源单一,主要来自岩浆。 (4)瑶岗仙花岗岩过去被视为典型的S型花岗岩,但本文研究发现该花岗岩普遍含有地幔He。结合区域构造背景的最新研究成果,本文认为,原来被认为“由地壳物质重熔形成的”瑶岗仙S型花岗岩体,实际上也是一种岩石圈伸展背景条件下壳幔相互作用的产物,地幔物质和能量的参与在该花岗岩的形成过程中发挥了重要作用。 (5)瑶岗仙钨矿床与矿区复式花岗岩体具有密切时空关系,而且该矿的主要成矿流体和成矿物质均来自矿区花岗岩,故两者亦应具成因联系。

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A cultivar de trigo BRS 49, desenvolvida pela Embrapa Trigo, foi indicada para semeadura no Estado do Parana, a partir de 1999. Para a determinacao do seu valor de cultivo e uso, foram utilizados dados de 54 experimentos, instalados em nove locais das regioes 6, 7 e 8 do Parana, no periodo de 1996 a 1998. Apresenta como principais caracteristicas: ciclo intermediario, altura media a alta, moderada resistencia ao acamamento, tolerancia ao aluminio toxico no solo, moderada resistencia ao oidio (Blumeria graminis f. sp tritici) e a ferrugem da folha (Puccinia recondita f. sp. tritici), com percentuais de severidade em ensaios inferiores aos das testemunhas Trigo BR 23 e Trigo BR 35, suscetibilidade a giberela (Giberella zeae), cujas notas foram superiores as atribuidas as testemunhas, elevado potencial de rendimento e boa qualidade industrial. No trienio considerado, apresentou rendimento medio de 4.667 kg/ha na Regiao 6, 3.432 kg/ha, na Regiao 7, e 3.930 kg/ha, na regiao 8. Esses valores foram 11%, 11% e 28%, respectivamente, superiores a media das testemunhas (Trigo BR 2, Trigo BR 35 e CEP 24-Industrial). Os percentuais de resposta ao controle fitossanitario foram, em geral, inferiores aos observados nas referidas testemunhas, evidenciando o elevado potencial de rendimento da cultivar com aplicacoes reduzidas de fungicidas. A forca geral de gluten (W), na media de 14 amostras coletadas nas tres Regioes, foi de 260 e a relacao P/L foi de 0,685. Portanto, a cultivar se enquadra na classe Trigo Pao, de acordo com a Instrucao Normativa n.1, de 27 de janeiro de 1999 do MA. A cultivar apresenta caracteristicas de interesse agronomico, principalmente por possibilitar a obtencao de altos rendimentos, sem a necessidade de elevados investimentos com fungicidas.

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Practice Links is a free e-publication for practitioners working in Irish social services, voluntary and nongovernmental sectors. Practice Links was created to enable practitioners to keep up-to-date with new publications, electronic resources and conference opportunities. Issue 49 contains information regarding dance therapy for schizophrenia and the role mindfulness based stress reduction (MBSR) plays in improving the lives of adults. The issue also contains details of employment opportunities in Australia.