983 resultados para Waterloo, Batalla de, 1815
Resumo:
We compared the capture efficiency and catch dynamics of collapsible square and conical pots used in resource assessment and harvesting of red king crabs (Paralithodes camtschaticus [Tilesius, 1815]) in the Barents Sea. After two days of soaking, square pots caught three times as many crabs as conical pots, and their catches consisted of a higher proportion of male crabs and male crabs larger than 160 mm carapace length compared to the catches in the conical pots. Catches in the square pots did not increase as soak times were increased beyond two days, which indicates equilibrium between the rate of entries into and the rate of exits from the pots. Catches in conical pots, however, increased with increasing soak times up to eight days, the longest soak time examined in this study. These findings demonstrate the higher efficiency of square pots and the importance of understanding catch dynamics when making population assessments based on catchper-unit-of-effort data. The favorable catch characteristics and handling properties of the collapsible square pot may make this pot design suitable for other crab fisheries, as well.
Resumo:
[EUS] Artikulu honetan J. P. Ulibarri idazle okondoarrak 1815an argitaratu zuen "Egunare euskerazkoa erdaraskotik itzuliya" egutegia aurkezten dugu, urteetan galdutzat jo izan dena. Lan honetan, orain arte euskal bibliografoek "Egunare"-az esan dutena laburtu dugu (§1), eta horrekin batera alearen deskribapena eskaini dugu bai fisikoa eta baita gaien arabera(§2). Hirugarren atalean(§3), libarriren egiletasuna bermatu dugu: testua egile izenik gabe argitaratu bazen ere albaitariaren lantzat jo dugu, bere idaztankera eta euskara moldea aztertzeko lan honek duen garrantzia azpimarratuz. Amaitzeko, testua bera eskaini dugu, bai edizio erdipaleografiko legez eta baita faksimile eran.
Resumo:
分子系统学建立在实验和计算的基础之上。DNA快速测序技术的普及为分子系统学家提供了大量数据,而序列分析技术则是探索数据发现知识的重要工具。在基因组时代,随着大量模式生物完整基因组序列的获得,分子系统学正面临着前所未有的机遇和挑战。一方面,生命之树计划有助于确定新的模式生物和开展相应的基因组计划;另一方面,模式生物的基因组计划有助于阐明它们之间的进化关系和基因组的进化模式。更为重要的是,分子系统学序列分析技术已经发展成为探索与整合基因组数据的强有力工具,从而在生命科学中发挥重要作用。事实上,分子系统学和基因组学的相互渗透正在形成一门崭新的交叉学科——系统发育基因组学。 为了奠定分子系统学研究中信息管理和数据分析工作的坚实基础,我们建立了分子系统发育分析平台。该平台为研究人员提供专业数据库服务和数据分析技术支持,以及相关的网络资源。 分子系统发育分析平台包括了3个专业数据库。第一个是DNA凭证标本数据库。该数据库中的记录包括了7项字段:英文科名、中文科名、物种拉丁名、采集人、采集号、采集地和采集时间。用户可以通过设定单个或多个字段的取值进行检索。截止2004年6月1日,该数据库共包括3491条标本记录。第二个是引物数据库。PCR引物是分子系统学实验的重要条件之一。该数据库中的记录包括3项字段:引物名称、序列内容和退火温度。用户可以通过设定单个或多个字段的取值进行检索。截止2004年6月1日,该数据库共包括170条用于扩增植物细胞核、叶绿体和线粒体基因组DNA序列的引物记录。第三个是生物计算数据库。该数据库为研究人员提供传输和保存序列分析数据和结果文件的服务。 为了确保数据库的安全性和使用性,我们开发了数据库的接口和检索工具,以及系统管理员和用户资格认证程序。通过前者,使用者可以进行数据的上传、下载、管理和检索等操作。而后者则是对不同使用者身份和权限进行设定。管理员的权限高于用户,主要负责本系统的日常维护和管理工作,以及对新增管理员和用户进行资格认证。 分析技术支持旨在帮助用户快速掌握常用的系统发育分析方法,进行有效的数据分析,从复杂的统计学算法和计算机程序中解放出来,将精力集中于计算结果的生物学解释。在该部分中,我们首先简要介绍了常用的分析方法,并且针对分子系统学中的不同问题提供了相应的解决方案。这些问题包括:系统发育重建、替代速率和分歧时间的估计、祖先分布区的重建、性状进化假说的检验、以及密码子水平适应性进化的检测。我们特别强调了似然比检验和贝叶斯推测作为方法论上的重要进展在分子系统学中所发挥的关键作用。本部分还包括大量常用的分子系统学程序或软件包及其快速使用说明和命令模块。下载安装之后,用户即可按照说明使用命令模块进行数据分析。 此外,该平台还提供了一些常用的网络资源地址,如生物信息中心、分子进化和系统发育实验室、专业期刊和相关数据库等。 最后还给出了4个应用实例,即针对特定分子系统学问题的解决方案和初步的分析结果。 第一个例子说明系统发育重建方法的应用。为了确定杨梅科的系统学位置,对6种DNA序列和叶绿体trnL-F区内的间隔性状进行了分析。单个分析表明这6种序列之间在系统学信息上存在显著差异。叶绿体基因组序列的合并分析强烈支持杨梅科和(木麻黄科,(桦木科,核果桦科))的姐妹群关系,而间隔性状的存在能够充分提高其分辨率和支持率。 第二个例子说明如何推测历史生物地理学过程。我们对壳斗目8科25属植物叶绿体基因组的trnL-F、matK、rbcL和atpB的合并序列进行了最大简约分析,得到唯一的最大简约树。基于该系统树和25属植物的地理分布数据,采用扩散-替代分析方法重建了系统树每个节点上的祖先分布区,推测了壳斗目的分布历史。结果表明,壳斗目的历史生物地理学过程由3次替代事件和20次扩散事件组成。其中最重要的替代事件是由于冈瓦纳大陆和劳亚大陆分离所导致的南青冈科及其姐妹群之间的分化。另外,在壳斗科和核心高等金缕梅类中多次发生从欧亚大陆到北美洲、甚至南美洲的平行扩散事件。 第三个例子说明如何估计分歧时间。我们仍然使用扩散-替代分析中所用的最大简约树作为分析的依据,并根据等级制似然比检验确定的最优替代模型对该系统树的支长进行了最大似然优化。似然比检验表明,该系统树不服从分子钟假说。我们以冈瓦纳大陆和劳亚大陆分离的地质事件和5个属的最早化石记录作为标定点,采用罚分似然法在没有分子钟的条件下估计了壳斗目的科间分歧时间。结果表明,绝大多数科间分歧事件都发生在白垩纪。 第四个例子说明如何检测密码子水平的适应性进化。分支间可变选择压力模型的似然比检验表明SARS冠状病毒的S基因在跨种传播过程中发生了正选择。
Resumo:
本发明涉及一种自由活动实验动物运动,行为和电生理指标监测分析系统,由运动轨迹识别软件(5),PC机LPT端口(4),图象采集卡(2),摄像机(1),连接在PC机LPT端口上的行为刺激装置(3)组成。该装置利用计算机和现代电子技术时实跟踪监实验动物在迷宫中的运动轨迹,并根据运动轨迹控制连接在计算机上的相关仪器给以动物相应的实验刺激,同时记录下运动轨迹并配合相关设备纪录电生理数据,达到记录行为和电生理数据同步并使实验自动化。本装置在实验任务中具有很高的灵活性,通过设置软件和调整连接在端口上不同的控制装置,可自动完成许多不同的实验任务,满足不同的数据分析需要。
Resumo:
In this article, we detail the methodology developed to construct arbitrarily high order schemes - linear and WENO - on 3D mixed-element unstructured meshes made up of general convex polyhedral elements. The approach is tailored specifically for the solution of scalar level set equations for application to incompressible two-phase flow problems. The construction of WENO schemes on 3D unstructured meshes is notoriously difficult, as it involves a much higher level of complexity than 2D approaches. This due to the multiplicity of geometrical considerations introduced by the extra dimension, especially on mixed-element meshes. Therefore, we have specifically developed a number of algorithms to handle mixed-element meshes composed of convex polyhedra with convex polygonal faces. The contribution of this work concerns several areas of interest: the formulation of an improved methodology in 3D, the minimisation of computational runtime in the implementation through the maximum use of pre-processing operations, the generation of novel methods to handle complex 3D mixed-element meshes and finally the application of the method to the transport of a scalar level set. © 2012 Global-Science Press.
Resumo:
The electronic structure and electron g factors of HgTe quantum dots are investigated, in the framework of the eight-band effective-mass approximation. It is found that the electron states of quantum spheres have aspheric properties due to the interaction between the conduction band and valence band. The highest hole states are S (l = 0) states, when the radius is smaller than 9.4 nm. the same as the lowest electron states. Thus strong luminescence from H-Te quantum dots with radius smaller than 9.4 nm has been observed (Rogach et al 2001 Phys. Statits Solidi b 224 153). The bandgap of H-Te quantum spheres is calculated and compared with earlier experimental results (Harrison et al 2000 Pure Appl. Chem. 72 295). Due to the quantum confinement effect, the bandgap of the small HgTe quantum spheres is positive. The electron g factors of HgTe quantum spheres decrease with increasing radius and are nearly 2 when the radius is very small. The electron g factors of HgTe quantum ellipsoids are also investigated. We found that as some of the three dimensions increase, the electron g factors decrease. The more the dimensions increase, the more the g factors decrease. The dimensions perpendicular to the direction of the magnetic field affect the g factors more than the other dimension.
Resumo:
Good quality hydrogenated protocrystalline silicon films were successfully prepared by radio frequency plasma enhanced chemical vapor deposition (PECVD) with various hydrogen dilution ratios (R = ([H-2]/[SiH4]) from 10 to 100). The photosensitivity of the films is up to 10(6) under the light intensity of 50mW.cm(-2). The microstructure of the films was studied by micro-region Raman scattering spectra at room temperature. The deconvolution of the Raman spectra by Gaussion functions shows that the films deposited under low hydrogen dilution ratios (R < 33) exhibit typical amorphous properties, while the films deposited under high hydrogen dilution ratios (R > 50) possess a diphasic structure, with increasing crystalline volume fraction with R. The size of the crystallites in the diphasic films is about 2.4 mm, which was deduced from the phonon confinement model. The intermediate range order of the silicon film increases with increasing hydrogen dilution ratio.
Resumo:
Double weighted neural network; is a kind of new general used neural network, which, compared with BP and RBF network, may approximate the training samples with a move complicated geometric figure and possesses a even greater approximation. capability. we study structure approximate based on double weighted neural network and prove its rationality.
Resumo:
Dynamic Power Management (DPM) is a technique to reduce power consumption of electronic system. by selectively shutting down idle components. In this article we try to introduce back propagation network and radial basis network into the research of the system-level policies. We proposed two PAY policies-Back propagation Power Management (BPPM) and Radial Basis Function Power management (RBFPM) which are based on Artificial Neural Networks (ANN). Our experiments show that the two power management policies greatly lowered the system-level power consumption and have higher performance than traditional Power Management(PM) techniques-BPPM is 1.09-competitive and RBFPM is 1.08-competitive vs. 1.79,145,1.18-competitive separately for traditional timeout PM, adaptive predictive PM and stochastic PM.
Resumo:
Automatic molecular classification of cancer based on DNA microarray has many advantages over conventional classification based on morphological appearance of the tumor. Using artificial neural networks is a general approach for automatic classification. In this paper, Direction-Basis-Function neuron and Priority-Ordered algorithm are applied to neural networks. And the leukemia gene expression dataset is used as an example to testify the classifier. The result of our method is compared to that of SVM. It shows that our method makes a better performance than SVM.