查询词典 variation

Random changes in allele frequency can lead to fixation and the progressive loss of genetic variation from the population.

基因频率的随机变化导致来自种群的遗传变异的固定和逐渐丧失。

During the postgenomics era the information about genomic sequence and gene functions provides a new foundation for evolutionary biology and ecology As the first whole-genome sequenced plant Arabidopsis thaliana and its wild relatives have played a critical role in understanding the evolution of genomics and speciation Both A halleri and A lyrata are closely related to the model species A thaliana A halleri ssp gemmifera occurs in northeastern China Japan and Taiwan; while its sister A halleri ssp halleri is mainly distributed in Europe Geographical barriers such as Tienshan Mountain Range isolate these intraspecific sisters Likewise A lyrata ssp kamchatica and ssp lyrata occur in East Asia and North America respectively Such distribution patterns seem to be consistent with allopartic speciation The comparison between ancestral and extant polymorphism by multilocus can be informative about the population genetics of speciation In this study we collected and analyzed DNA sequences of 98 genes from four wild relatives of A thaliana A halleri ssp gemmifera A halleri ssp halleri A lyrata ssp kamchatica and A lyrata ssp lyrata The ancestral states of these four species were compared to each other in terms of level of genetic variation However the ancestral species at the time of speciation were substantially more polymorphic than the extant geographical populations The observations are not fully compatible with speciation by strict allopatry At some species pairs parapatric speciation seems more reasonable in speciation of Arabidopsis The 98 gene sequences are also used for the congruence test between gene genealogy and species phylogeny Only 28 genes support the species phylogeny but there are 23 genes supports another major genealogy { lyrata} thaliana Based on the phylogenetic position change of A lyrata ssp kamchatica and Ks value for each species pair suggested the recent directional gene flow between A halleri ssp gemmifera and A lyrata ssp kamchatica

阿拉伯芥是第一个完成基因体定序的开花植物，其基因体资讯提供植物学研究的重要依据；在解析阿拉伯芥属物种的亲缘关系以及种化机制等重要的演化议题时，阿拉伯芥近缘的野生物种自然成了不可或缺的关键；跟阿拉伯芥近缘的物种包括A halleri及A lyrata，其中A halleri ssp gemmifera主要分布於中国东北、日本以及台湾，与近缘的A halleri ssp halleri其分布於欧洲隔著天山及大陆的障蔽，而A lyrata ssp kamchatica主要分布於东北亚及台湾，与分布於北美五大湖的A lyrata ssp lyrata被北极圈所分隔，这样的分布模式暗示异域种化的可能。藉由多基因分析比较祖先物种与现生物种遗传歧异度的相关可提供讯息探讨种化时期的族群遗传结构，本研究针对A halleri ssp gemmifera、A halleri ssp halleri及A lyrata ssp kamchatica、A lyrata ssp lyrata四个物种，两对互为亚种的姊妹群，以阿拉伯芥为外群进行研究，在四个物种完成98个同源基因的分子序列，利用套装软体MCMCcoal来估算祖先物种的遗传变异，亦估算现生物种的核苷酸歧异度，观察到？多物种配对中祖先物种遗传多型性大於现生物种DNA歧异度，显示异域种化模型并无法完全解释阿拉伯芥属物种的种化模式，在某些物种配对间邻域种化模式应比异域种化更为可能；在基因树与物种树的比较，98个基因片段的亲缘模式只有28个是与已知物种树一致的，有23个基因其树状图支持{ lyrata} thaliana的型式，藉由kamchatica位置的变化以及估算各物种配对间的平均同义置换率，推测在A halleri ssp gemmifera与A lyrata ssp kamchatica间具有近代的单方向基因交流。

Apomixis,wide compatibility,allopolyploidization were used to select allopolyploid rice and enlarge its range of inheritance and variation,and increase its output,quality and resistance to disease and pest by a big margin.

通过无融合生殖、广亲和、异源多倍体化的利用，选育异源多倍体水稻，增加它的遗传变异范围，大幅度提高水稻的产量、质量和抗性。3。

The best indicators of consistently associated with temporal variation are O3/NOz, H2O2/NOz, H2O2/, and NOy. However there is significant difference for almost all indicator species at the downwind sites.

不同时间一致性最高的指标则为O3/NOz、H2O2/NOz、H2O2/、NOy，在下风处各光化指标对时间的变异性有较显著之差异存在。

There may be some variation in the use of the ''Alt'' key on different operating systems.

Note|在不同的操作系统使用'''ALT'''键，效果可能有一些变化。

The alternativeness focuses on the variation of its level and benefit.

科技创新的辩证法主要包括它的系统性、过程性和变动性及其辩证关系。

Paper studies the practical stability of electricity market models by tools, for example, the appropriate structure Lyapunov functions, Cauchy matrix, the matrix measure, constant variation. Judging practical stability sufficient conditions and estimating formula of ultimate convergence boundary are provided. Conditions are descriptive by coefficients of models. At the same time, paper studies the Lyapunov stability of the electricity market. As well as the sufficient conditions of judging electricity market Lyapunov stability are provided. Some of conclusions improved the results of Alvarado and others. The conclusion of Lyapunov stability has made a comparative with practical results.

首次将实用稳定性理论和方法应用于电力市场稳定性的研究中，借助于构造合适的Lyapunov函数、柯西矩阵、矩阵测度、常数变易法等工具，系统研究了所建电力市场模型的实用稳定性，得到了用模型的系数来描述其实用稳定性的一系列判定条件和最终收敛边界的估计公式；同时对电力市场的Lyapunov稳定性进行了研究，得到了电力市场稳定性的若干判据，部分结论改进了Alvarado等人的结果；随后将Lyapunov稳定的结果与实用稳定进行了比较。

The research was mainly based on the formation condition of crystalline ammonium yttrium carbonate and the variation characteristics of pH value during the crystallization in which NH4HCO3 was used to precipitate yttrium ion.

对碳酸氢铵沉淀钇时碳酸钇铵复盐结晶的形成条件与pH变化特征进行了研究，发现其结晶过程与平衡溶液pH有对应关系。

In addition, the role of the RER in protein body forming, the role of amyloplast envelope in amyloplast proliferating, the relations between nucleus and cytoplasm of starchy endosperm cells in rice, and the variation of nucleus in plant PCD, the roles of plasmalemma invagination, ER, Ca〓 and phosphatases during endosperm development were discussed.

本文对粗面内质网在蛋白体形成中的作用，淀粉质体被膜在淀粉质体增殖中的作用，淀粉胚乳细胞的核质关系，植物PCD中细胞核的变化，以及质膜内陷、内质网、Ca〓和磷酸水解酶在胚乳发育中的作用等进行了讨论。

In conclusion, we detailedly investigated the variation of membrane system (mainly plasmalemma, amyloplast envelope, ER) with the potassium permanganate fixative method, nucleus and organelles with routinely fixative method, and their functions with cytochemical method (localization of phosphatases and Ca〓).

综上所述，本文运用高锰酸钾固定法研究了膜系统（主要指质膜、淀粉质体被膜、内质网）的变化，运用常规固定制样研究了细胞核和细胞器的变化，采用细胞化学方法（Ca〓和磷酸水解酶的定位）探索了细胞器和细胞核的功能。

And discuss some key point of integrated management system design, include hazard identification and risk assessment and risk control in the occupational health and safety management, the measure of satisfaction target of customer, the flawlessness of law system, the integration of the integrated management system and enterprise standardization system, unify lead institution and work orgnization, integreted internal audit and integrated management review.

同时，论述了一体化管理体系构建中的几个主要问题，包括职业健康安全管理中的危险源辨识、风险评价和风险控制、顾客满意度的科学监测、法律、法规体系的完善、一体化管理体系与企业标准化体系的有机结合、统一的领导机构和工作机构、一体化的内部审核和管理评审。

Deepwater Taranaki is investigated for its petroleum potential, using all available seismic data tied to shallow-water wells.

运用与浅水井相关的现有全部震波探测数据考察了深海区塔拉纳基盆地的油藏前景。