爬行动物性别决定的研究进展

爬行动物的性别决定方式有二：一是遗传型的性别决定，二是温度依赖型的性别决定，全文就这两种类型决定方式的研究进展及作用机制作了详细阐述。     

脊椎动物性别决定机制的研究进展

分别以哺乳动物和爬行动物为例介绍了脊椎动物性别决定的两种主要类型的研究进 展,并推测两种性别决定机制在分子水平上可能是一致的。     

非哺乳类脊椎动物性别决定的研究进展

本文介绍了非哺乳脊椎动物的性别决定机制,它是多种转录因子和生长因子相继表达和相互调控的结果.鸟类的性别是由遗传基因决定的.爬行类为温度性别决定的典型.大部分两栖类动物性别受环境因素影响,但发现DMRT1和DAx1可能与其精巢发育有关.鱼类性别决定和分化方式差异很大,多种因素参与了这一过程.     

畜禽性别决定相关基因的研究进展

在畜牧业生产中，很多经济性状都与性别有直接关系。因此，深入了解畜禽的性别决定和性别分化机制，进而对其进行鉴定和控制，不仅在科学研究方面具有重要意义，在生产中也具有重要的实用价值。本文对畜禽性别决定相关基因的研究进展进行了综述。     

动物性别鉴定与控制研究进展

哺乳动物性别决定是以位于雄性Y染色体短肴上被称为SRY基因为调控中心、多基因参与的级联调控过程。但染色体理论并非性别决定机制的全部，外部环境中的某些因素也是性别决定机制的重要条件。本中对家畜性别控制技术的一些方法的原理、理论基础基本方法和性反转等进行了综述，介绍了家畜的精子和早期胚胎性别鉴定与控制的一些方法。     

人类性别的生物学基础

人类的性别决定是一个复杂的问题，性别差异也体现在多个方面．文章主要从生物学角度对人类的遗传性别、性腺性别、体细胞性别和生理性别做了简要的概述．     

硬骨鱼类性别决定与分化相关基因研究进展

鱼类是脊椎动物中最低等但分布最广、种类最多的一类生物.与高等脊椎动物不同,鱼类的性别决定除了受遗传因素的影响,外界环境(激素水平、温度、盐度、氧气等)和自身内分泌调节也发挥了重要作用,因而其性别决定与分化机制极其复杂.尽管如此,遗传因素仍然是鱼类性别决定与分化的关键因素.本文通过对影响硬骨鱼类性别决定及分化的遗传因素(包括sox,dmrt1,amh,gsdf,cyp19a1a,foxl2等性别决定及分化相关基因和Rspo1/Wnt/β-catenin信号通路)的研究动态与进展进行综述,为更深入的探索鱼类性别决定与分化机制提供参考.     

中华鳖性别决定敏感期的研究

在24℃和33℃对中华鳖性别决定的敏感期做了研究,实验结果证实中华鳖的性别决定有一个敏感期.性腺自7100度小时开始分化,13000度小时结束,以后的孵化温度对性别决定没有影响.     

雌雄异型异熟植物的开花机制研究进展

雌雄异型异熟是植物从雌雄同花向雌雄异株进化过程中的一种过渡类型,目前发现存在于13个科20个属植物中。其群体中包括雌先型和雄先型两种交配类型,两种交配类型植株的同步性和互不干扰性可有效地避免自交。一般认为雌雄异型异熟植株的交配类型是固定不变的,但也在一些植物中发现了彼此间的转化; 植株内雌雄花开放时间有的完全错开,有的部分重叠。经典遗传学认为交配类型受1对显/隐性的等位基因控制,且当群体达到平衡时两种交配类型的比例可达平衡状态(1:1),这在胡桃属和山核桃属上得到了验证,但在其他同类植物分子生物学方面的研究还是空白。雌雄异型异熟植物的性别决定为饰变型,其性别分化不仅受性别决定基因的遗传控制,而且还受植物激素的诱导调控,但不同植物上激素诱导性别分化的作用存在差异。解剖学研究表明同一交配类型上的雌雄花发育和成熟时间均存在差异。     

哺乳动物性别决定机理研究进展

综述了与哺乳动物性别决定有关的6个基因在基因通路中的表达调控及功能,并分析了这些基因之间可能的相互作用机理,为发育生物学、哺乳动物性别决定、性别控制及胚胎鉴定提供一些借鉴.     

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.     

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.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.