乌鸡的性状遗传率,遗传相关和杂种优势

本文以乌鸡４个品种作为全群，从中抽出５只雄亲和５套雌系进行巢式交配设计，测定了子代出雏期、１月龄、２月龄、３月龄的体重和胫长．遗传分析表明：（１）雌亲分量遗传率明显高于雄亲分量遗传率，说明群体存在明显的非加性变异；（２）各发育期体重和胫长的遗传相关和表型相关一般为正相关且较大，从而可根据胫长间接选择体重；（３）体重杂种优势变动为－７％～３２％；（４）在强优势Ｆ１组合，１月龄相对生长速度明显高于其亲本组合的，但２月龄的恰相反，这为生产缩短Ｆ１的饲养周期有利．最后讨论了雌亲分量遗传率高于雄亲分量遗传分量和杂种优势产生的原因．     

用遗传距离和典范遗传距离预测小麦杂种优势的效果初探

本文分别以遗传距离和典范遗传距离预测小麦杂种优势，比较两种方法的预测效果，结果表明用遗传距离预测杂种优势方法简便，所选杂交组合的优势与实际符合，因此认为，遗传距离是预测小麦杂种优势的较好指标。     

马尾松双列杂交亲本遗传距离与杂种生长优势相关性分析

马尾松6×6全双列杂交的不同组合,其11年生子代在生长性状及其杂种优势上均存在较大的差异。对亲本遗传距离与子代杂种优势的相关分析发现:亲本的ISSR遗传距离(0.266 0~0.467 0)与子代树高、胸径等生长性状及其杂种优势表现为显著的线性正相关,遗传距离与正、反交子代材积杂种优势的相关系数分别达到0.601和0.597,表明随着亲本间遗传距离的增大,子代各生长性状的杂种优势将呈线性增加。马尾松亲本遗传距离与子代杂种优势的相关性明显高于遗传距离与子代生长性状的相关性,表明根据亲本遗传距离对子代杂种优势进行预测比直接预测子代生长性状更可靠。根据这一结论,优先选择树高、材积等经济性状优良同时遗传距离较大的杂交亲本,有望提高子代杂种优势幅度并获得材积性状优良的子代。     

怎样提高幼螺成活率?

目前,许多蜗牛养殖户反映:“幼螺难养、成活率低”。有的蜗牛养殖户幼螺成活率仅只有10％左右,特别在梅雨季节,甚至成批幼螺死亡。因此,如何提高幼螺成活率是蜗牛养殖户的当务之急。幼螺确是蜗牛一生中最难养的一个阶段。怎样度过这个难养阶段,关键在于管理。幼螺,一般是指从孵化出壳后一月龄内的小螺。它的特征是:壳薄而半透明,呈淡灰白色,有2—2.5螺层,体重约50毫克。约经一个月的饲养,从绿豆般大的出壳幼螺可     

泥螺 Bullacta exarata 生长生物学的初步研究

本文研究了浙江沿海泥螺的生长特征。结果表明：泥螺出膜面盘幼虫１６５．６×１４４．０μｍ，日平均生长７．０μｍ，匍匐幼虫日平均生长８．７μｍ，幼螺日平均生长２５．８μｍ，从受精卵化出膜至幼螺约需３０－４０天。在自然海区当年１１月初产卵孵化的幼虫至翌年３月壳高可达０．４ｃｍ，５月底至６月初即可达壳高１．２ｃｍ以上的采捕规格。成螺壳高（Ｈ）与壳宽（Ｂ）、体重（Ｗ）之间的回归关系：Ｂ＝０．７２５７Ｈ－０．０５６６（ｒ＝０．９８２０）、Ｗ＝０．４８７３Ｈ２．６４３０（ｒ＝０．７４２０）。     

近交系小鼠8个遗传生化标记杂合位点的研究

目的为了更加准确有效地监测近交系小鼠的遗传质量,对近交系小鼠的8个遗传生化标记杂合位点进行 研究。方法将近交系小鼠CBA／Ca与BALB／c交配得到杂交Fl代动物CCBFI,同时将近交系小鼠CBA／Ca与 C57BL／6交配得到杂交Fl代动物B6CBFI,对CCBFI和BbCBFI进行遗传生化标记检测。结果找到近交系小鼠 8个遗传生化标记的杂合位点。结论近交系小鼠的8个遗传生化标记位点相对应的等位基因均为共显性。杂合 位点的图谱可以作为监测近交系小鼠质量的判定标准。     

家兔血清蛋白质与乳酸脱氢酶同工酶电泳分析

利用ＰＡＧＥ对７个品种家兔血清蛋白及ＬＤＨ同工酶进行电泳分析。结果表明：家兔血清蛋白质及ＬＤＨ同工酶酶谱均具有种的特异性，ＬＤＨ同工酶以Ｂ亚基占优势，Ａ、Ｂ亚基的比率可反映家兔的亲缘关系及有氧代谢功能，并根据此对家兔品种杂种优势进行估测；由血清蛋白电泳谱带数目可计算出家兔品种间的遗传距离，在分子水平上为探索家兔品种间亲缘关系和分类、进化提供理论依据。     

杂种优势遗传基础的研究进展

由于杂种优势的利用是农业增产的重要途径，杂种优势的遗传基础研究一直受到高度重视。近十年来发展的分子标记技术及构建的高密度遗传图谱，为阐明杂种优势的遗传基础提供了有力的工具，杂种优势研究有了新进展，通过对已有资料的分析研究，从遗传差异，基因表达调控、基因效应、基因网络系统等方面探讨了杂种优势的遗传基础及其研究进展。     

SX1近交系小鼠遗传纯度的初步研究

目的初步鉴定山西省肿瘤研究所第22代SX1近交系小鼠遗传纯度。方法应用生化基因位点遗传质量检测法和皮肤移植测试法对山西省肿瘤研究所自行培育的第22代昆明近交系小鼠进行了遗传纯度的初步鉴定。结果所检测的6只近交系小鼠的13个生化位点均未发现杂合基因型,所检基因位点全部纯合;所检测的10只近交系小鼠异体间未发现急性排斥现象。结论初步判定山西省肿瘤研究所自行培育的第22代昆明近交系小鼠在遗传质量上符合国标有关实验动物遗传质量检测的要求。     

近交系大,小鼠保种的研究

本单位从１９８９年陆续引进了８个国家通用的标准近交系大，小鼠，通过５年多的繁殖和保种实践，我们根据每个品系的特点，逐渐摸索出一套科学的保种方法，设计了保种体系，保证了近交系大，小鼠的遗传质量。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that