883 resultados para Black flying fox
Resumo:
Immunostimulants are the substances, which enhance the non-specific defence mechanism and provide resistance against the invading pathogenic micro-organism. In order to increase the immunity of shrimps against the WSSV, the methanolic extracts of five different herbal medicinal plants like Cyanodon dactylon, Aegle marmelos, Tinospora cordifolia, Picrorhiza kurooa and Eclipta alba were selected and mixed thoroughly in equal proportion. The mixed extract was supplemented with various concentrations viz. 100 (A), 200 (B), 400 (C), and 800 (D) mg kg(-1) through artificial diets individually. The prepared diets (A-D) were fed individually to WSSV free healthy shrimp Penaeus monodon with an average weight of 8.0 +/- 0.5 g for 25 days. Control diet (E), devoid of herbal extract was also fed to shrimps simultaneously. After 25 days of feeding experiment, the shrimps were challenged with WSSV, which were isolated and propagated from the infected crustaceans. The shrimps succumbed to death within 7 days when fed on no herbal immunostimulant diet (E). Among the different concentrations of herbal immunostimulant supplemented diets, the shrimps fed on diet D (800 mg kg(-1)) significantly (P < 0.0001) had more survival (74%) and reduction in the viral load. Also the better performance of haematological, biochemical and immunological parameters was found in the immunostimulant incorporated diets fed shrimps. The present work revealed that the application of herbal immunostimulants will be effective against shrimp viral pathogenesis and they can be recommended for shrimp culture. (c) 2006 Published by Elsevier Ltd.
Resumo:
Experimental research in biology has uncovered a number of different ways in which flying insects use cues derived from optical flow for navigational purposes, such as safe landing, obstacle avoidance and dead reckoning. In this study, we use a synthetic methodology to gain additional insights into the navigation behavior of bees. Specifically, we focus on the mechanisms of course stabilization behavior and visually mediated odometer by using a biological model of motion detector for the purpose of long-range goal-directed navigation in 3D environment. The performance tests of the proposed navigation method are conducted by using a blimp-type flying robot platform in uncontrolled indoor environments. The result shows that the proposed mechanism can be used for goal-directed navigation. Further analysis is also conducted in order to enhance the navigation performance of autonomous aerial vehicles. © 2003 Elsevier B.V. All rights reserved.
Resumo:
We propose a novel information-theoretic approach for Bayesian optimization called Predictive Entropy Search (PES). At each iteration, PES selects the next evaluation point that maximizes the expected information gained with respect to the global maximum. PES codifies this intractable acquisition function in terms of the expected reduction in the differential entropy of the predictive distribution. This reformulation allows PES to obtain approximations that are both more accurate and efficient than other alternatives such as Entropy Search (ES). Furthermore, PES can easily perform a fully Bayesian treatment of the model hyperparameters while ES cannot. We evaluate PES in both synthetic and real-world applications, including optimization problems in machine learning, finance, biotechnology, and robotics. We show that the increased accuracy of PES leads to significant gains in optimization performance.
Resumo:
The natural reproduction of grass carp, black carp, silver carp, and bighead will be affected adversely by the Three Gorges Project in the Yangtze River. One of the methods to save the fish is to regulate the water levels, keeping them suited for the species to spawn. Nine factors associated with the scale of larvae-flood of the four species are classified into five levels, and the ranges of these factors producing larvae-floods are given by using the "factor-criteria system reconstruction analysis" method. Moderate beginning water levels and flow, with high daily increases in the rate of water level and flow, and a long duration of water level rising are important for the production of a large larvae-flood.
Resumo:
FOX是最近推出的系列分组密码,它的设计思想基于可证安全的研究结果,且在各种平台上的性能优良.本文利用碰撞攻击和积分攻击相结合的技术分析FOX的安全性,结果显示碰撞-积分攻击比积分攻击有效,攻击对4轮FOX64的计算复杂度是2^45.4,对5轮FOX64的计算复杂度是2^109.4,对6轮FOX64的计算复杂度是2^173.4,对7轮FOX64的计算复杂度是2^237.4,且攻击所需数据量均为2^9;也就是说4轮FOX64/64、5轮FOX64/128、6轮FOX64/192和7轮FOX64/256对本文攻击是不免疫的.
Resumo:
Background: Flying lemurs or Colugos (order Dermoptera) represent an ancient mammalian lineage that contains only two extant species. Although molecular evidence strongly supports that the orders Dermoptera, Scandentia, Lagomorpha, Rodentia and Primates form a superordinal clade called Supraprimates (or Euarchontoglires), the phylogenetic placement of Dermoptera within Supraprimates remains ambiguous. Results: To search for cytogenetic signatures that could help to clarify the evolutionary affinities within this superordinal group, we have established a genome-wide comparative map between human and the Malayan flying lemur (Galeopterus variegatus) by reciprocal chromosome painting using both human and G. variegatus chromosome-specific probes. The 22 human autosomal paints and the X chromosome paint defined 44 homologous segments in the G. variegatus genome. A putative inversion on GVA 11 was revealed by the hybridization patterns of human chromosome probes 16 and 19. Fifteen associations of human chromosome segments (HSA) were detected in the G. variegatus genome: HSA1/3, 1/10, 2/21, 3/ 21, 4/8, 4/18, 7/15, 7/16, 7/19, 10/16, 12/22 (twice), 14/15, 16/19 (twice). Reverse painting of G. variegatus chromosome-specific paints onto human chromosomes confirmed the above results, and defined the origin of the homologous human chromosomal segments in these associations. In total, G. variegatus paints revealed 49 homologous chromosomal segments in the HSA genome. Conclusion: Comparative analysis of our map with published maps from representative species of other placental orders, including Scandentia, Primates, Lagomorpha and Rodentia, suggests a signature rearrangement (HSA2q/21 association) that links Scandentia and Dermoptera to one sister clade. Our results thus provide new evidence for the hypothesis that Scandentia and Dermoptera have a closer phylogenetic relationship to each other than either of them has to Primates.
Resumo:
松鼠科隶属于哺乳纲、啮齿目,是一类世界广布性动物,全世界共计36 属 234 种。本文通过形态分析及分子生物学方法,研究了我国松鼠科动物的分类及 系统发育关系,内容包括以下两个方面: 一、中国松鼠科动物的分类 本研究查看了中科院昆明动物研究所、中科院动物研究所、云南大学、四川 省林业科学研究院、四川大学、陕西师范大学、陕西动物研究所、西北大学、上 海自然历史博物馆、广东昆虫所馆藏该科各类群标本。同时,结合相关文献,对 各类群的外形特征进行了详细的描述和系统分类整理,我国共计10 属34 种。测 取可量性状数据共计20800 个(完整头骨共计1300 号),而且还运用多变量及单 变量分析方法进行数据分析,对部分类群的种下分类结果进行分析:1.探讨了分 布于中国境内的明纹花鼠(Tamiops mcclellandii)3 亚种的有效性。2.研究了 隐纹花鼠(Tamiops swinhoei)在中国的分化并描记了分布于四川马尔康地区的 隐纹花鼠为一新亚种(Tamiops swinhoei markamensis)。3.描记了分布于云南 省东北部昭通地区的赤腹松鼠为一新亚种:昭通亚种(Callosciurus erythraeus zhaotongensis)。4. 提出了分布于云南省无量山区的泊氏长吻松鼠为一新亚种: 无量山亚种(Dremomys pernyi wuliangshanensis)。 二、中国松鼠科动物的系统发育研究 2004-2005 年相继到滇西北高黎贡山、香格里拉,滇西南临沧地区,滇东 南马关、麻栗坡、富宁,滇东北昭通地区进行标本采集,基本收集到我国南方松 鼠科属、种样品进行分子生物学研究。 1.中国松鼠科动物各属的系统发育关系 在分析线粒体细胞色数b 基因(1040bp)序列的基础上,运用贝叶斯法 (Bayesian phylogenetic reconstruction approaches)、最简约法(Maximum parsimony method)、邻接法(Neighbor Joining method)构建中国松鼠科动物 所有属间系统发育树。结果表明:所分析的10 属分别聚集为3 群,巨松鼠属Ratufa单独成为一群,丽松鼠属Callosciurus、长吻松鼠属Dremomys、花松鼠属 Tamiops 以及线松鼠属Menetes 成为一群,松鼠属Sciurus、岩松鼠属 Sciurotamias、花鼠属Tamias、旱獭属Marmota 以及黄鼠属Spermophilus 成 为一群。在此基础上我们进一步探讨了中国松鼠科动物的分化与环境变化的关 系。 2.长吻松鼠属的系统发育关系 在分析线粒体细胞色数b 基因(378bp)序列的基础上,我们重建了长吻松 鼠属内5 个类群间的系统发育关系,结合对5 类群外部形态特征的详细比较,我 们探讨并论证了红腿长吻松鼠、橙喉长吻松鼠作为种的地位的有效性,同时论证 了该属内泊氏长吻松鼠最早分化,其次为橙腹长吻松鼠,第三是红腿长吻松鼠, 红颊长吻松鼠和橙喉长吻松鼠是最后分化的类群。