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991.
992.
R. G. Randall 《Ecology of Freshwater Fish》2002,11(3):196-202
Abstract – The ratio of annual production rate to average biomass ( P / B ) is sometimes used as a shortcut method of estimating production if biomass is known. P / B ratios vary among salmonid populations in different areas depending on the species, fish size and growing conditions. The hypothesis that annual P / B ratios for salmonid populations can be predicted from the allometric equation: P / B = a W −0.35 was investigated in this study. The allometric coefficient (−0.35) was obtained from the literature, and W was the average weight (g) of fish in the population. Plots of P / B versus fish weight for three species of salmonids, Salvelinus fontinalis , Salmo trutta and Salmo salar , showed a declining trend, with a slope consistent with the hypothesis. The coefficient a of the allometric equation was species and habitat dependent. The efficacy of using the allometric formula to estimate the P / B ratio of specific salmonid populations is examined. 相似文献
993.
牛病毒性腹泻病毒P125基因重要区的比较与分析 总被引:11,自引:0,他引:11
根据牛病毒性腹泻病毒(BVDV)NADL株的序列,以计算机辅助设计,化学合成1对引物(W1/W2);应用RT-PCR对国内不同地区分离的4株BVDV的P125基因外源序列插入区进行了扩增,并将扩增的片段进行克隆和序列测定,同时以DNASIS和PROSIS计算机软件将测定的核苷酸序列及推导的氨基酸序列进行比较分析。结果证实,国内分离的4株BVDV在这一区域中既没有外源序列的插入,也没有基因重组、基因重排或基因缺失,但存在某些核苷酸和氨基酸的替换,表明病毒的致细胞病变作用除与外源序列的插入、基因重组、基因重排或基因缺失有关外,可能还存在其他机制。核苷酸序列的同源性及系统树分析的结果表明,国内的BVDV毒株存在Ia和Ib2个基因亚型,它们均属基因I型BVDV 相似文献
994.
网络通信技术和INTERNET的迅猛发展,使得办公自动化已经成为综合计算机技术、通信技术、系统科学、行为科学等学科的科学技术,它将基于不同技术的办公设备,以联网的方式连成一体,将语言、图像、数据、文字处理等功能组合在一个系统中,形成一个事务处理能力强、工作效率高、信息流转快、决策科学的体系。本文通过对开发环境和系统特点的分析,介绍了.NET的相关知识。运用ASP.NET开发技术,采用Browser/Server(浏览器/服务器)模式,建立一个基于.NET的新疆农科院农经信息所的办公自动化系统。 相似文献
995.
应用均匀设计法探讨了电场刺激及培养因素对甘蓝叶原生质体分裂频率的影响。结果表明 ,电场方向和强度强烈地影响细胞分裂频率。培养成分对细胞分裂频率均有不同程度的影响。均匀设计能筛选最优的植物原生质体培养条件或培养基。结合“回归 -通径”分析 ,有效地综合评判和研究了各培养成分对原生质体分裂频率的作用 相似文献
996.
本文对结构阻尼系统提出一种模态综合方法,该方法特别适合于部件对接界面自由度较少情况下的结构综合.给出了一个算例来说明方法的有效性. 相似文献
997.
Rabies is an enzootic viral disease widespread throughout the world. Although it is a vaccine-preventable disease, the annual number of human deaths caused by rabies is estimated to be 32,000 in Asia. Phylogenetic analysis based on sequence data of the partial N gene of rabies viruses in Asia has shown that the viruses are divided into five genogroups, distributed in Middle East, South Asia, South East Asia, Malay, and Arctic regions. The genetic relationships among these rabies viruses agree basically with the results of previous studies. Meanwhile, new types of vaccines are being developed by applying gene manipulation techniques to rabies virus in order to overcome the disadvantages of current vaccines. This article reviews the molecular epidemiology of rabies in Asia and progress made in the development of new-generation rabies vaccines with the goal of elimination or control of rabies in Asia. 相似文献
998.
Savlík M Polácková L Szotáková B Lamka J Velík J Skálová L 《Research in veterinary science》2007,83(1):20-26
Basal activities of certain pheasant hepatic and intestinal biotransformation enzymes and modulation of their activities by anthelmintics flubendazole (FLBZ) and mebendazole (MBZ) were investigated in subcellular fractions that were prepared from liver and small intestine of control and FLBZ or MBZ treated birds. Several oxidation, reduction and conjugation enzyme activities were assessed. In the liver, treatment of pheasants by FLBZ or MBZ caused very slight or no changes in monooxygenase activities and conjugation enzymes. More significative changes were detected in small intestine. Metyrapone and daunorubicin reductase activities were increased by both substances in the liver. This is the first evidence that certain benzimidazoles modulate reductases of carbonyl group. With respect to the relatively slight extent of the changes caused by FLBZ or MBZ we can assume that repeated administration of therapeutic doses of both FLBZ and MBZ has probably no serious influence on pheasant biotransformation enzyme system. 相似文献
999.
Antarasena C Sirimujalin R Prommuang P Promkuntod N Prommuang P Blacksell SD 《Research in veterinary science》2007,83(2):279-281
Here we describe the diagnostic utility of the indirect immunofluorescence assay (IFA) during a recent outbreak of highly pathogenic avian influenza (HPAI) subtype H5N1 virus in southern Thailand and demonstrate the usefulness of the cardiac tissue from infected chickens, quail, and ducks for diagnosis. The most reliable sample for IFA diagnosis of influenza A virus was cardiac tissue (83.0%; 44/53) which when divided by species (chicken, quail and duck cardiac tissues) gave respective positivity rates of 88% (22/25), 88.9% (16/18) and 60.0% (6/10). Cardiac tissue also gave the highest IFA intensity for the three species. We believe that the IFA method has wide applicability in developing countries or remote settings where clinically similar avian diseases with high morbidity and mortality such as Newcastle disease and fowl cholera are common and could be rapidly excluded thereby conserving valuable reference laboratory capacity for true HPAI outbreaks. 相似文献
1000.
AIM: To investigate the effects of gonadotropin-releasing hormone (GnRH) analogue on the growth of breast cancer cell lines MCF-7 and MDA-MB-231 in vitro and to explore the related mechanisms with PI3K/Akt or ERK/MAPK pathways. METHODS: The proliferation of human breast cancer cell lines MCF-7 and MDA-MB-231 treatment with triptorelin was detected by MTT assay and the distribution of the cell cycle was determined by flow cytometry. The phosphorylation of the ERK1/2 and Akt was evaluated by Western blotting. RESULTS: Triptorelin inhibited the proliferation of MCF-7 cells at concentration of 10-5 mol/L after treated for 192 h or at concentration of 10-4 mol/L after treated for 168 h and 192 h. Triptorelin inhibited the proliferation of MDA-MB-231 cells at concentration of 10-4 mol/L after treated for 192 h (P<0.05).Treatment with triptorelin for 192 h at concentration of 10-4 mol/L had no statistical significance effect on phosphorylation of ERK1/2 and Akt(P>0.05).CONCLUSION: Inhibitory effect of GnRH analogue triptorelin on human breast cancer cells is not just the connection with the down-regulation of pituitary hormone, but also a direct inhibitory effect. The role may not be involved in the activation of ERK/MAPK and PI3K/Akt signaling pathways. 相似文献