茄青枯假单胞菌毒性基因的功能分析

分离自花生的茄青枯假单胞菌(Ralstonia solanacearum,R.s)T2015的一段4.5 kb DNA中ORF2和ORF3位于同一个操纵子中.ORF2和ORF3 DNA序列与GeneBank同源性比较分析和T2015及其突变体T2136(ORF2)、T2135/R(ORF3)、T2135(ORF3极性突变体)和互补株T2136/R(ORF2)、T2145(T2135)的脂多糖(lipopolysaccharide,LPS)SDS-PAGE带型比较分析表明:ORF2参与LPS完整的核心的合成;ORF3编码产物在LPS完整的生物合成中起脂质A核心区—O-antigen连接酶作用.菌落形态和植株实验结果表明LPS与病菌菌落形态和其对寄主的致病性有关,而与其在非寄主上引起过敏反应能力无关.     

关于Ka算子与第二Kato谱

给出Ka算子的定义,讨论N(Ta)与R(Tb)的关系,得到闭子空间Y在T作用下的象T(Y)成为闭子空间的一些条件,进而证明当T∈Φ (X)时,从R∞(T)到R∞(T)的算子T|R∞(T)是个满射,同时证明当N(T)(∈)R∞ (T)时,T|R∞(T)也是个满射,从而说明当T是Ka算子时,T|R∞(T)是个满射;给出第二Kato谱σ'k(T)的定义,证明了σ'k(T)是C中的非空紧子集,也证明了σ'k(T)=σ'k(T*),并讨论σ'k(T)的一些性质以及σ'k(T)与一些常见的本性谱的关系,说明σd(T)(∈)σ'k(T)(∈)σ(T)、σ'k(T)σB(T)≠(φ)、σk(T)\σ'k(T)≠(φ)、(∈)(T)∩σ'su(T),而且说明当TS=ST时,若TS∈Ka(X),则T∈Ka(X)且S∈Ka(X).     

局部环上线性群中一类子群的扩群

设R是局部环 ,I1,I2 是R中任意固定的且为不同时等于R的理想 ,S I1,T I2 为R的任意两个理想 ,GL(n ,R)是R上n级一般线性群 ,G(n ,r ,S ,T)表示子群A　BC　D ∈GL(n ,R)B∈Sr×(n-r) ,C∈T(n-r)×r .当n≥ 4 ,1 ≤r相似文献   

整环的赋值扩环及赋值维数

设R是整环,其商域为K.dimv(R)表示R的赋值维数.证明了:(1)dimv(R)是R的维数互异的既是UMT整环,又是DW整环的扩环升链RmRm-1…R1R0=K的长度的上确界;(2)dimv(R/P)≤dimv(R)-htvP,其中P是R的素理想,htvP是P的赋值高度;(3)对于强Milnor方图RDTF,dimv(R)=max{htvM+dimv(D),dimv(T)},其中M是R与T的公共素理想.     

外源性透明质酸减少R5-HIV对CD4~+T细胞感染的研究（英文）

目的探讨外源性透明质酸(HA)是否可以降低巨噬细胞嗜性(CCR5依赖,R5)人类免疫缺陷病毒(HIV)对CD4+T细胞的感染性。方法首先用TZM-bl细胞和未受刺激的CD4+T细胞检测,以评估外源性透明质酸(HA)能否降低R5-HIV的感染性。用透明质酸酶去处理未受刺激的CD4+T细胞,研究内源性HA对R5-HIV感染性的影响。最后,同时测量外源性和内源性透明质酸(HA)对R5-HIV对CD4+T细胞粘和力的影响。结果 (1)100μg外源性HA处理能够显著降低R5-HIV感染TZM-bl细胞和未受刺激的CD4+T细胞(P<0.001)。(2)透明质酸酶处理可增强HIV的感染性,但是如果加上100μg外源性HA可以逆转透明质酸酶的处理(P<0.001)。(3)100μg外源性HA可以减少R5-HIV对CD4+T细胞的粘和力,透明质酸酶处理可以提高R5-HIV对CD4+T细胞的粘和力(P<0.001)。结论外源性HA减少R5-HIV对未受刺激的CD4+T细胞的感染性,而透明质酸酶处理可以提高R5-HIV对CD4+T细胞的粘和力,能增强R5-HIV对CD4+T细胞的感染性。     

代数的分离扩张和有限平坦维数

在R,T是结合代数及R/T是双分离扩张条件下,研究了J∞(T)(J∞S(T))和J∞(R)(J∞S(R))的反变有限性的关系以及有限平坦维数Fin fd(T)(fin fd(T)和Fin fd(R)(finfd(R))的关系.     

Colossal magnetoresistive p-n junctions of perovskite oxide La0.9Sr0.1MnO3／SrNb0.01Ti0.99O3

We have successfully fabricated the colossal magnetoresistive (CMR) p-n junctions of perovskite oxide La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO) with laser molecular beam epitaxy. The I-V characteristics of the LSMO/SNTO p-n junctions as a function of applied magnetic field (0—5 T) were studied between 100 and 300 K. We found that the p-n junction exhibited the CMR behavior. The CMR ratio △R/R0 (△R = RH - R0) is positive in magnetic fields below 0.13 T and at high temperature, while it displays a negative CMR near 100 K and in magnetic fields over 0.13 T. The CMR ratio values are 8% at 0.1 T and 13% at 5 T and 300 K, 40% at 0.1 T and 150 K, 10% at 0.13 T and -60% at 5 T and 100 K. The CMR behavior of the p-n junction is different from those of the LaMnO3 compound family.     

时标上的二阶中立型泛函微分方程的周期解

利用叠合度理论研究了一类时标上的二阶中立型泛函微分方程,得到方程(x(t)-c(t)x(t-T))△△=-a(t)f(x(t))△(t)-Σ i=1nbi(t)gi(t,x(t-Ti(t)))周期解存在的条件,其中a,bi和,TiC(T,R)都是w-周期函数T是常时滞且T﹥0, c (t )C2(T,R), 0 ≤c(t)〈1, g iC(T* R, R +), i =1,2, ...,,n关于第一个分量是w-周期函数,关于第二个分量是非减的,c(t)C2(T,R)。     

K2,t+1和K1,n的Ramsey数

本文得到了一个较T.D.Parsons[3]的R(C4,K1,n)更为一般的R(K,t+1,K1,n)的结果.     

具有给定得分向量的竞赛图类的对换图的连通度

本文证明:对具有给定得分向量R的竞赛图类T(R)的对换图G(R),若G(R)至少含有三个点,且G(R)不是一个长为4的圈,则G(R)为3—连通图。这个结果加强了Brualdi和李乔在文献[1]中关于竞赛图类的对换图的2—连通的结果。     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-