剑尾鱼和魣鳉的核型及银染带型和C带研究

以肾细胞作材料,采用秋水仙素-低渗-空气干燥法和Howell(1980)的方法(银染),Sumner(1972)的方法(C带),对剑尾鱼(Xiphophorushelleri)和(Belonesoxbelizanus)的核型及银染和C带进行了分析.结果显示:这两种鱼的染色体2n均为48.剑尾鱼的核型公式为2n=6st+42t,NF=48.的核型公式为2n=2m+2sm+6st+38t,NF=52.其染色体经快速银染后表明,两种鱼各有1对NORs,并均在微小染色体的着丝点上.多数染色体的着丝点区均显示出一个深浅不同的C带.     

剑尾鱼和(鱼予)鳉的核型及银染带型和C带研究

以肾细胞作材料,采用秋水仙素-低渗-空气干燥法和Howell(1980)的方法(银染),Sumner(1972)的方法(C带),对剑尾鱼(Xiphophorus helleri)和( )鳉(Belonesox belizanus)的核型及银染和C带进行了分析.结果显示:这两种鱼的染色体2n均为48.剑尾鱼的核型公式为2n=6st+42t,NF=48.( )鳉的核型公式为2n=2m+2sm+6st+38t,NF=52.其染色体经快速银染后表明,两种鱼各有1对NORs,并均在微小染色体的着丝点上.多数染色体的着丝点区均显示出一个深浅不同的C带.     

金雕染色体核型

本文利用骨髓染色体制片技术对金雕(Aquila Chrysaetos)染色体核型进行了研究。金雕染色体数为2n=70,核型公式为KF=ZMZM+34M/SM+24T+100。对全部染色体相对长度、臂比等进行了测定,绘制了染色体组型模式图。     

蓝曼龙(Trichogaster trichopterus)的染色体组型、Ag-NORs及C-带型的研究

以肾细胞作材料，采用秋水仙素-低渗-空气干燥法、Howell[1980]的方法(银染)和Sumher(1972)的方法(C带)，制作染色体标本．首次报道了蓝曼龙(Trichogaster trichopterus)的核型及银染和C带。结果显示出：蓝曼龙的核型公式为2n=46t，NF=46，具有1对银染分别位于t1的一对同源染色体上的臂的端部，其染色体上NORs有明显的大小差异，结构和数目在不同的细胞中也出现了多态性,其深染C-带区可以分为着丝粒C-带，端粒C-带，居间C-带，没有发现异型性染色体。     

玫瑰鲃脂鲤和红鳍银鲫的核型及银染和C-带研究

报道了玫瑰鲃脂鲤(Hyphessobrycon rosaceus)和红鳍银鲫(Puntius schwanenfeldi)的核型及银染和C-带.结果显示:两种热带淡水观赏鱼的2 n均为50.玫瑰脂鲤的核型公式为2 n=24 m 12 sm 10 st 4 t,NF=86,其染色体经快速银染后,在m9染色体的短臂末端出现银染位点,多数染色体的着丝点区均显示出一个深浅不同的C-带.红鳍银鲫的核型公式为2 n=22 m 14 sm 4 st 10 t,NF=86,银染点位于m1和m2染色体的短臂末端,多数染色体为着丝粒C-带.在两种鱼中发现均有Ag-NORs联合现象,未发现有异形性染色体.     

云南产大绿臭蛙(Odorrana livida)的染色体核型研究

研究了云南勐腊县产的大绿臭蛙的核型,核型模式为2n=26(18M+8SM),5+8,NF=5;并与已报道的安徽黄山和香港的大绿臭蛙的核型进行了比较.结果表明虽然大绿臭蛙的不同地理种群之间的核型模式相同,但在SM和M的数目、顺序以及次缢痕的位置等有所不同,说明大绿臭蛙的不同地理种群的染色体具有丰富的多样性.     

鮸染色体的识别及核型特征分析

鮸(Miichthys miiuy)是我国南方重要的海水养殖种类.针对鮸细胞遗传标记匮乏的问题,利用荧光染色、硝酸银染色(银染)、荧光原位杂交(FISH)等方法分析了鮸的核型特征,发现鮸的核型含24对端部着丝粒染色体(2n=48t),鮸染色体经碘化丙啶(PI)染色后,荧光强度呈现特定的二维分布模式;利用图像分析软件可转化为更直观的3D-光强度图,为鮸染色体的识别、配对提供了丰富的信息.18SrDNA和5SrDNA双色FISH结果显示,鮸的18SrDNA和5S rDNA均只有1对位点,分别位于1号染色体的近着丝粒区域和2号染色体的着丝粒区域.银染显示鮸的核仁组织区域(NOR)和4′,6-二脒基-2-苯基吲哚(DAPI)染色显示的暗带,均与18SrDNA位点的位置相同.鮸的端粒序列FISH信号分布于所有染色体的两端,未发现臂间端粒信号.综上,通过PI染色和图像分析软件解决了鮸染色体识别困难的问题,并使用FISH方法分析了鮸的核型特征,研究结果丰富了鮸的细胞遗传学标记,也为研究石首鱼类染色体进化提供了基础数据.     

河南花背蟾蜍核型、Ag-NORs与性别关系

利用骨髓细胞蒸汽固定法制备染色体标本,研究了分布于河南新乡的花背蟾蜍(Bufo raddei)的核型,Ag-NORs.结果表明:河南产花背蟾蜍体细胞染色体数为22条,核型公式为2n=22=20m+2sm,全部为中部或亚中部着丝点染色体,NF=44.Ag-NORs结果显示在性成熟的雌雄个体之间出现了稳定差异,提示河南花背蟾蜍可能为同形异配ZW型性别决定.     

九龙棘蛙和棘胸蛙的染色体比较研究

本文报道了福建蛙类新纪录——九龙棘蛙相似文献   

云南社鼠(Rattus niviventer)和刺毛鼠(Rattus fulvesence)的染色体比较研究

云南社鼠(R.nivwenter)和刺毛鼠(R.fulvesence)的核型,染色体数目均为2n=46,其核型公式如下:社鼠36T+2SM+6M.XY(T,T);刺毛鼠30T+8SM十6M,XY(T,T)。与国外学者的报道略有不同。除无带核型外,还分析了它们染色体的C 带和银染色结果,并从染色体角度,讨论了它们在家鼠(Genus Rattus)中的演化地位。     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the