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STATUS QUO & DRIVING MECHANISM OF DESERTIFICATION IN THE NORTH TIBETAN PLATEAU

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Natural Disaster Reduction in china 2002年第3期 29-35页

作者： Dong Yuxiang (department of Geography, zhongshan university, guangzhou 510275, Guangdong,{3.)

The North Tibetan Plateau, the main body of the Qinghai Tibetan Plateau which is one of china’s three major distribution areas of desertification, is an important area for studying the process and mechanism of desertification. The article gives a detailed analysis of the status quo of desertification in the North Tibetan Plateau (hereinafter referred to as "the Plateau") in terms of desertification type, area and distribution, and presents a quantitative as well as qualitative discussion of the principal factors and driving mechanism of desertification in the area in current times. It concludes that desertification in the region, which is large in area, diverse in type, widely distributed and disastrous, is the result of the combined action of natural and human factors, wherein climatic change is the primary driving force.

关键词： North Tibetan Plateau desertification driving force

Fixed Point Separating Congruences on Double MS-Algebras

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Acta Mathematica Sinica,English Series 1998年第1期14卷 99-104页

作者： Fang Jie department of Mathematics, zhongshan university, guangzhou, {3., china Mathematical Institute, university of St Andrews. St Andrews, Fife, KY16 9SS, Scotland, U. K. department of Mathematics Zhongshan University Guangzhou 510275 China Mathematical Institute University of St. Andrews St Andrews Fife KY16 9SS United Kingdom

Here we show that there exists a greatest fixed point separating congruence denoted by ψ on a double MS-algebra (L;~0, +), Some properties of ψ under certain conditions on fixed point complete and fixed point distri... 详细信息

关键词： Double MS-algebra Fixed point Separating congruence

A novel system for Agrobacterium-mediated transformation of wheat(Triticum aestivum L.) cells

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Cell Research 1993年第1期3卷 49-60页

作者： XU YAO, BAOJIAN LI, JINGFEN JIA Biotechnology Research Centre,zhongshan university, guangzhou 510275. {3. of Biology, Lanzhou university, Lanzhou 73.000, china. Biotechnology Research Centre Zhongshan University Guangzhou department of Biology Lanzhou University Lanzhou China

A new approach for transforming the cultured cells of wheat(Triticum aestivum L. cv. Ganmai 8) was developed using Agrobacterium tumefaciens. The features of the optimum procedure were: (a) both combined synthetic signal molecules and multiple natural extracts from susceptible plants were used to pretreat the primary vigorous Agrobacterium(PVA) cells for approximately 16 h; (b) the gyratory magnetic field condition was used during cocultivation; (c) the cocultivating period and selecting condition were modified; (d) the recipient cells were at exuberant metabolism and active division while infected with Agrobacterium. Both neomycin phosphotransferase and nopaline synthase assays demonstrated the expression of NPT Ⅱ and NOS genes, located on the T-DNA segment of chimaeric plasmid pGV3.50::1103.eo, in transformed wheat cell colonies by adopting the techniques of dot blot, ndPAGE or high voltage paper electrophoresis. Integration of the foreign genes into wheat genome was confirmed by Southern blot hybridization. Moreover, a relatively rational method was described for the estimation of transformation frequencies from cultured cell levels.

关键词： genetic engineering gyratory magnetic field natural susceptible extracts synthetic signals transformation system wheat cells.

Asymptotic Properties of Self-Consistent Estimatorswith Doubly-Censored Data

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Acta Mathematica Sinica,English Series 2001年第4期17卷 581-594页

作者： Qi Qing YU Lin Xiong LI Mathematics department, SUNY at Binghamton, Binghamton, NY 13.02, USA Mathematics department. zhongshan university,{3., P. R. china department of Mathematics. university of New Orleans, New Orleans, LA 70148, USA Mathematics department SUNY at Binghamton Binghamton USA Mathematics department Zhongshan University Guangzhou 510275 P. R. China department of Mathematics University of New Orleans New Orleans USA

The asyrmptotic properties of the self-consistent estimator (SCE) of a distribution function F of a random variable X with doubly-censored data are examined by several authors under the asstumption that X is observable everywhere in the interval [a, b], where a=inf{x: F(x)>0} and b=sup{x: F(x)<1}. Such an assumption does not allow the situation that X is discrete and the situation that X is only observable in a nontrivial subinterval of [a, b]. However, often in practice this assumption is not satisfied. In this manuscript we establish strong uniform consistency, asymptotic normality and asymptotic efficiency of the SCE under a set of assumptions that allow the situation that X is discrete and the situation that X is only observable in a nontrivial subinterval of [a, b]. Finally, we point out a gap in the proofs of the existing results in the literature due to the definition of the SCE.

关键词： Asymptotic normality Generalized MLE Right censoring Self-consistent algorithm Strong consistency

On Some Properties of Infinite-dimensional Bers Fiber Space

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Communications in Mathematical Research 1999年第2期 77-82页

作者： Liu Lixin (department of Mathematics, zhongshan university, guangzhou, {3.) Yang Xiaoming (Hangzhou university Press, Hangzhou university, Hangzhou, 3.0028)

§１．ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＴｅｉｃｈｍüｌｅｒｓｐａｃｅｓｄｉｓｃｕｓｓｅｄｉｎｔｈｉｓｐａｐｅｒａｒｅｉｎｆｉｎｉｔｅｄｉｍｅｎｓｉｏｎａｌＴｅｉｃｈｍüｌｅｒｓｐａｃｅｓｗｉｔｈｃｏｍｐｌｅｘｓｔｒｕｃ... 详细信息

§１．ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＴｅｉｃｈｍüｌｅｒｓｐａｃｅｓｄｉｓｃｕｓｓｅｄｉｎｔｈｉｓｐａｐｅｒａｒｅｉｎｆｉｎｉｔｅｄｉｍｅｎｓｉｏｎａｌＴｅｉｃｈｍüｌｅｒｓｐａｃｅｓｗｉｔｈｃｏｍｐｌｅｘｓｔｒｕｃｔｕｒｅ．Ｔｈｉｓｉｍｐｌｉｅｓｔ...

关键词： Bers Fiber Space Teichmüller Metric Hyperbolic Metric

FREE ENERGIES OF FORMATION FOR ELECTROCHEMICALLOY ALLOYED Y-Cu SYSTEM

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Acta Metallurgica Sinica(English Letters) 1990年第7期3卷 28-32页

作者： YANG Qiqin LIU Guankun LIU Zejin zhongshan university,guangzhou,china YANG Qiqin,Associate Professor,{3. of Chemistry,zhongshan university,guangzhou,china

The electrochemical alloying of Y-Cu system in molten NaCl-KCl-YCl_3.has been investi- *** free energy changes of the formation reactions of the intermetallic compounds,in- cluding YCu_6 ,YCu_4 YCu_2 ,Yfu(973.103.K),were determined by means of electrode potential-time curves of the working electrode after potentiostatic *** results in- dicate that the potential-time method is simple and reliable.

关键词： Y-Cu system free energy of formation electrochemical alloying

Discovery of Permian island-arc basalts in the Cenxi area and the tectonic significance──A piece of evidence for the paleo-Tethyan tectonic belt in western Guangdong and eastern Guangxi

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Chinese Science Bulletin 1998年第21期43卷 1838-1842页

作者： ZHANG Boyou 1, ZHAO Zhenhua 1, SHI Manquan 1, YANG Shufeng 2 and CHEN Hanlin 2 1. guangzhou Institute of Geochemistry, Chinese Academy of sciences, guangzhou 510640,{3. 2. department of earth sciences, Zhejiang university, Hangzhou 3.0027,{3. guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China department of earth sciences Zhejiang University Hangzhou China

Cenxi Permian basalts are the late Palaeozoic island-arc type basalts first found in South china. REE and trace element characteristics and distribution patterns show that this volcanic formation, which has been isotopically dated at 261 MaB.P. by the 3.Ar/ 40Ar method, is of an active continental marginal island arc type, and that the tectonic environment at that time was an island-arc marginal sea or minor ocean basin related with the paleo-Tethyan tectonic belt in western Guangdong-eastern Guangxi.

关键词： spilite-keratophyre pillow lava Permian continental margin paleo-Tethyan evolution.

A FAST SEARCH METHOD BASED ON THE STATISTICAL PROPERTIES OF SIGNAL

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Journal of Electronics(china) 1992年第3期9卷 261-264页

作者：林韵肖自美 department of Electronics Zhongshan UniversityGuangzhou 510275

The concepts of ordered code-book and the priority of code-vector are proposedin this *** statistical properties of a signal are investigated through its coded *** results are presented which provide some insight into the statistical properties ofvector quantized *** on the given concepts and experimental results,a fast searchmethod for the vector quantization of correlated information sources,such as Gauss-Markovsources,is proposed and has shown its efficiency in simulation results.

关键词： Signal processing Exhaustive full search method Vector quantization Codevector Ordered code-book

Activation of PI3.K/Akt pathway for thermal preconditioning to protect cultured cerebellar granule neurons against low potassium-induced apoptosis

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Acta Pharmacologica Sinica 2007年第2期28卷 173-179页

作者： Lin CAO~(2,3. De-xiong CAO~3.Xing-wen SU~2 Li-jun CHEN~2 Ai-lin LIU~2 Wei-jian JIAN~2 Yu-ping WU~2 Peng-xin QIU~2 Guang mei YAN~(2,4)2 department of Pharmacology,zhongshan Medical School,Sun Yat-sen university,{3. 510080,china 3.department of Anesthesiology The Second Affiliated Hospital,Sun Yat-sen university,{3. 510120,china department of Pharmacology Zhongshan Medical School Sun Yat-sen University Guangzhou China department of Anesthesiology The Second Affiliated Hospital Sun Yat-sen University Guangzhou China

Aim:This study was designed to investigate whether the activation of thephosphatidylinositol 3.kinase(PI3.K)/Akt pathway is required for thermal pre-conditioning to protect rat cerebellar granule neurons(CGN)against apoptosisinduced by low potassium,and to explore the possibility of a link between theupregulated heat shock protein(HSP)70 expression and Akt activation in theacquisition of neuroprotection induced by thermal ***:CGN cultured for 8 d in vitro were switched to 5K medium for 24 h after thermalpreconditioning(TP;43.5 ℃ for 90 min,then 3. ℃ for 1 h).To study the role of thePI3.K/Akt pathway,a PI3.K inhibitor,LY294002(20 μmol/L)was added into thecultures 1 h before TP.3.(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bro-mide(MTT)assay and fluorescein diacetate staining were used to determine *** 3.258 staining and agar gel electrophoresis were used to testthe morphological and biological characters of *** blot analysis wasemployed to detect the levels of phospho-Akt,phospho-glycogen synthase ki-nase 3.(GSK3.) Akt,GSK3.,and ***:TP protected CGN againstapoptosis induced by low ***294002 inhibited the neuroprotectiveeffect on CGN induced by *** induced a robust activation of Akt and theinactivation of GSK3. via ***,the activation of the PI3.K/Aktpathway by TP persisted for 24 h in the 5K ***294002(20 μmol/L)failedto inhibit the upregulated HSP70 expression induced by ***:Theactivation of the PI3.K/Akt pathway is required for TP to protect CGN againstapoptosis induced by low potassium,but the neuroprotective effect by Akt acti-vation is not mediated through the downstream induction of HSP70 expression.

关键词： thermal preconditioning heat cerebellum neurons apoptosis LY294002 phospho Akt phospho-GSK3. HSP70