977 resultados para Casanova, Giacomo, 1725-1798.


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The report deals with the material on freshwater crabs, collected by the Austrian-Ceylonese hydrobiological mission 1970 from the running waters of the mountains in south-west Ceylon. The locality records for Paratelphusa (Oziotelphusa) senex (Fabricius 1798) Paratelphusa (Ceylontelphusa) sorror (Zehntner 1894) and Paratelphusa (Ceylontelphusa) rugosa (Kingsley 1880), are described.

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解释合作行为演化中的"公共地悲剧"一直是生物学和社会科学中重要而又未能有效解决的核心问题之一.现有的合作演化模型中,描述合作行为演化的模型都是基于对称的思想发展而来,而现实的合作系统极可能是一个非对称的系统.但遗憾的是,合作行为的非对称性在现有的合作演化理论中被严重地忽视了.在一个稳定的合作系统中,合作方的个体数目和各自的收益与合作接受方事实上是高度不对等的.而在个体扩散难以实现的系统中,密度依赖的干扰性竞争对合作方和合作接受方的效应将会因此存在明显区别.本研究模型及模拟表明,合作方之间的密度依赖的约束或干扰性竞争将能维持公共资源利用的非饱和状态,合作系统将会因此维持合作关系局部的稳定,在公共资源很丰富的状态下,合作双方就不会发生竞争或冲突行为.增强合作方个体之间的密度依赖的干扰性竞争、合作方对合作接受方的贡献率、以及丰富的公共资源三因素将提高双方的合作频率.合作方和接受方之间的合作关系将会随系统的环境或生态条件的改变而转化为冲突关系,双方的关系并将随这些影响因素的变化而扰动(混沌).在非对称系统中,合作接受方对消极合作者或欺骗者的惩罚而对合作个体的奖赏将提高合作方对合作接受方的贡献率,即提高了类似于亲缘系数...

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本发明涉及一种大蹼铃蟾博玛津蛋白及其基因和在制药中的应用,属于生物医学领域。大蹼铃蟾博玛津蛋白是从中国两栖类动物大蹼铃蟾皮肤分泌物中分离得到的一种单链多肽,氨基酸全序列为:NH2GFPIYEIDNRPGCYVDPAERVACAGAGVTKAECKAKGCCFISARRNTIWCFKLKESADAWKCAVPMNTRVACAGAGVTPAECKGKGCCFSSYYGTV WCFKPQE-COOH)编码大蹼铃蟾博玛津蛋白的基因的cDNA由1061个核苷酸组成,编码成熟血小板活化蛋白为第67-378位核苷酸。博玛津具有诱导血小板活化、抑制胃溃疡的作用,可作为血小板聚集诱导剂和制备胃溃疡药物的应用。

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云南闭壳龟(Cuora yunnanensis,Boulenger,1906)曾被认为已经灭绝,在保护生物学上受到广泛的关注.本文测定了3只活的云南闭壳龟线粒体COI和ND4的部分序列及His,Ser,Leu tRNA序列片段,共 1725 个碱基序列.结合闭壳龟属其他物种序列,包括之前测定的一只云南闭壳龟标本(MNHN 1907.10)的DNA序列,进行了分子系统学分析.与100年前的标本比较,无论是形态还是分子系统分析结果都显示,这种新发现的活龟确实是云南闭壳龟.同时,我们的结果确证了标本序列的可信性,揭示云南闭壳龟不是近期杂交形成的,而是代表了进化上独立的遗传谱系,且种内仍存在一定的遗传多样性.

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In this study gamma radiation (3, 6 and 9 kGy) in combination with low temperature (-20°C) were applied to retain the quality and shelf-life of shrimp, Penaeus monodon for a longer period. The quality was assessed by monitoring microbiological changes (TBC, TMC, TYC, TCC and Salmonella count) in irradiated and non-irradiated (control) samples. Among microbiological indicators of spoilage, total bacterial count (TBC) values for irradiated shrimps were found to be 1875, 1625 and 1525 cfugˉ¹ of sample at 3, 6 and 9 kGy respectively after 90 days whereas for non-irradiated samples it was found 2475 cfugˉ¹ of sample. Total moulds count (TMC) value for non-irradiated samples after 90 days were found 425 cfugˉ¹ sample whereas that for irradiated shrimps at 3, 6 and 9 kGy were found to be 275, 250 and 200 cfugˉ¹ sample respectively. Total yeast count (TYC) value for non-irradiated samples after 90 days were found 4125 cfugˉ¹ sample whereas that for irradiated shrimps at 3, 6 and 9 kGy were found to be 2850, 2150 and 1725 cfugˉ¹ sample respectively. Total coliform count and Salmonella count showed that those were absent during 90 days storage period. From this study, it was clear that gamma radiation in combination with low temperature showed shelf-life extension (90 days) in each dose of radiation used but during the use of 9 kGy radiation, Penaeus monodon showed best quality.

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An outline is given of various environment-friendly management practices in aquaculture, considering the following: 1) feed right; 2) avoid antibiotics; 3) reuse and cycle water; 4) use settling or sedimentation ponds; 5) provide mangrove buffer zone; and, 6) practice polyculture or integrated farming.

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本研究采用RNA反义探针原位杂交技术,对vasa基因在黄鳝(Monopterusalbus)性腺发育过程中的表达情况进行了分析。结果表明:vasamRNA在Ⅰ、Ⅱ、Ⅲ期卵母细胞的胞质中均匀分布,在Ⅳ、Ⅴ期卵母细胞中vasamRNA有向胞质外周皮层迁移集中的趋势,但不明显;退化的卵粒也呈现vasamRNA阳性反应;在Ⅲ、Ⅳ期卵巢的被膜中检测到带有vasa阳性信号的细胞,这些细胞可能是待向精原细胞分化、迁移到卵巢被膜上的原始生殖细胞(Primordialgermcell,PGC),在性逆转过程中这些PGC可能

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The dynamics of free electron-hole pairs and excitons in GaAs-AlGaAs-GaAs core-shell-skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K. Following nonresonant excitation, a bimolecular interconversion of the initially generated electron-hole plasma into an exciton population is observed. This conducting-to-insulating transition appears to occur gradually over electron-hole charge pair densities of 2-4 × 10(16) cm(-3) . The smoothness of the Mott transition is attributed to the slow carrier-cooling during the bimolecular interconversion of free charge carriers into excitons and to the presence of chemical-potential fluctuations leading to inhomogeneous spectral characteristics. These results demonstrate that high-quality nanowires are model systems for investigating fundamental scientific effects in 1D heterostructures.

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The impact of a slug of dry sand particles against a metallic sandwich beam or circular sandwich plate is analysed in order to aid the design of sandwich panels for shock mitigation. The sand particles interact via a combined linear-spring-and-dashpot law whereas the face sheets and compressible core of the sandwich beam and plate are treated as rate-sensitive, elastic-plastic solids. The majority of the calculations are performed in two dimensions and entail the transverse impact of end-clamped monolithic and sandwich beams, with plane strain conditions imposed. The sand slug is of rectangular shape and comprises a random loose packing of identical, circular cylindrical particles. These calculations reveal that loading due to the sand is primarily inertial in nature with negligible fluid-structure interaction: the momentum transmitted to the beam is approximately equal to that of the incoming sand slug. For a slug of given incoming momentum, the dynamic deflection of the beam increases with decreasing duration of sand-loading until the impulsive limit is attained. Sandwich beams with thick, strong cores significantly outperform monolithic beams of equal areal mass. This performance enhancement is traced to the "sandwich effect" whereby the sandwich beams have a higher bending strength than that of the monolithic beams. Three-dimensional (3D) calculations are also performed such that the sand slug has the shape of a circular cylindrical column of finite height, and contains spherical sand particles. The 3D slug impacts a circular monolithic plate or sandwich plate and we show that sandwich plates with thick strong cores again outperform monolithic plates of equal areal mass. Finally, we demonstrate that impact by sand particles is equivalent to impact by a crushable foam projectile. The calculations on the equivalent projectile are significantly less intensive computationally, yet give predictions to within 5% of the full discrete particle calculations for the monolithic and sandwich beams and plates. These foam projectile calculations suggest that metallic foam projectiles can be used to simulate the loading by sand particles within a laboratory setting. © 2013 Elsevier Ltd.

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高温季节,在静止吋(摄食状态)的氮代谢方程式鲢为Mg=0.054W~(0.884)(毫克-氮/小时);鳙为Mg=0.073 W~(0.782)(毫克-氮/小时);氮的运动代谢量随游泳速度(s)的增大呈指数增长。氮的收支公式鲢为0.44 C_N=0.181 W~(0.61)+24/0.75{0.054-0.021(1-e~(0.2168)}W~(0.884);鳙为0.57 C_N=1.98 W~(0.61)+24/0.75{0.075-0.033(1-e~(0.1798)}W~(0.782)。以鲢和鳙对微囊

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This work demonstrates the condition optimization during liquid phase deposition (LPD) Of SiO2/GaAs films. LPD method is further applied to form Al2O3 films on semiconductors with poison-free materials. Proceeding at room temperature with inexpensive equipment, LPD of silica and alumina films is potentially serviceable in microelectronics and related spheres.

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Using a solution-based chemical method, we have prepared ZnS nanocrystals doped with high concentration of Mn2+. The X-ray diffraction analysis confirmed a zinc blende structure. The average size was about 3 nm. Photoluminescence spectrum showed room temperature emission in the visible spectrum, which consisted of the defect-related emission and the T-4(1)-(6)A(1) emission of Mn2+ ions. Compared with the undoped sample, the luminescence of the ZnS:Mn sample is enhanced by more than an order of magnitude, which indicated that the Mn2+ ions can efficiently boost the luminescence of ZnS nanocrystals.