Unified spatial scaling of species and their trophic interactions

Two largely independent bodies of scaling theory address the quantitative relationships between habitat area, species diversity and trophic interactions. Spatial theory within macroecology addresses how species richness scales with area in landscapes, while typically ignoring interspecific interactions. Complexity theory within community ecology addresses how trophic links scale with species richness in food webs, while typically ignoring spatial considerations. Recent studies suggest unifying these theories by demonstrating how spatial patterns influence food-web structure and vice versa. Here, we follow this suggestion by developing and empirically testing a more unified scaling theory. On the basis of power-law species-area relationships, we develop link-area and non-power-law link-species models that accurately predict how trophic links scale with area and species richness of microcosms, lakes and streams from community to metacommunity levels. In contrast to previous models that assume that species richness alone determines the number of trophic links, these models include the species' spatial distribution, and hence extend the domain of complexity theory to metacommunity scales. This generality and predictive success shows how complexity theory and spatial theory can be unified into a much more general theory addressing new domains of ecology.     

成都青城山高尔夫球场草坪杂草调查及化学防除

2009年调查分析了成都青城山高尔夫球场百慕达草坪年度杂草发生种类、发生规律及危害程度;并于2010年采用“翠坪”系列草坪专用除草剂进行杂草化学防除.结果显示“翠坪”系列草坪专用除草剂对青城山高尔夫球场各时期的主要杂草如马唐、水蜈蚣、香附子、早熟禾、小飞蓬等均有较好的防除效果,防除效果在90%以上,显著优于人工除草,防...     

The missing memristor found

Anyone who ever took an electronics laboratory class will be familiar with the fundamental passive circuit elements: the resistor, the capacitor and the inductor. However, in 1971 Leon Chua reasoned from symmetry arguments that there should be a fourth fundamental element, which he called a memristor (short for memory resistor). Although he showed that such an element has many interesting and valuable circuit properties, until now no one has presented either a useful physical model or an example of a memristor. Here we show, using a simple analytical example, that memristance arises naturally in nanoscale systems in which solid-state electronic and ionic transport are coupled under an external bias voltage. These results serve as the foundation for understanding a wide range of hysteretic current-voltage behaviour observed in many nanoscale electronic devices that involve the motion of charged atomic or molecular species, in particular certain titanium dioxide cross-point switches.     

唐菖蒲引种栽培技术研究

１９８９年￣１９９２年分别从甘肃临洮，荷兰引进了唐菖蒲不同品种，并对其生长发育、开花习性、种球处理及栽培技术等方面进行了研究，选出了适合青海种植的５个品种，并探索出了一整套适合高寒、干旱地区生产唐菖蒲种球与切花的栽培技术措施。     

外来种入侵对生态系统的负面影响及其防治对策

外来种入侵对我国生态系统的健康构成严重威胁，并造成了巨大的经济损失．但目前许多单位和个人对外来种入侵的危害性还缺乏足够认识，国家要建立健全有关法律法规，依法加强管理。     

重症监护病房的肠球菌种类及其耐药性分析

目的:了解我院重症监护病房肠球菌的种类及对其耐药情况进行分析.方法:用法国梅里埃公司生产的全自动细菌分析仪Vitek-32进行肠球菌鉴定和K-B法进行药敏试验.结果:113株肠球菌中以粪肠球菌和屎肠球菌为主,共94株占总数的83.18%,其中粪肠球菌63株占55.75%,屎肠球菌31株占27.43%.肠球菌对替考拉宁和万古霉素的耐药性最低,但屎肠球菌对12种抗菌药物的耐药性明显高于粪肠球菌.结论:临床对肠球菌的检测应达到种的水平,屎肠球菌对抗菌药物的耐药性较粪肠球菌为高,已经检测出对糖肽类抗生素万古霉素及替考拉宁耐药的肠球菌,值得重视.     

Immunity to intestinal parasites

Intestinal parasites are common in man and animals and can cause severe disease. Knowledge of immunity to such infections is limited and comes largely from studies using laboratory host-parasite systems. Understanding how immunity can operate, and why it often does not, is not only of intrinsic interest but necessary for the development of immunological methods of control.     

不同物种间胰岛素及其编码mRNA,DNA序列比较与分析

通过PSI-BLAST搜索与人类胰岛素原(含有86个氨基酸)相似的蛋白质序列，并进行比对，计算比对矩阵的相似得分和期望值，同时运用ClustalW算法对不同物种编码前胰岛素原mRNA及其翻译的蛋白质和DNA序列进行多重比对．结果发现，脊椎动物的胰岛素蛋白质一级结构(A链和B链)和mRNA非常相似，但部分动物C肽的部分序列有差异；系统进化分析表明，人和猴、小鼠和大鼠编码胰岛素的mRNA在进化上关系相近．各物种间编码相同氨基酸的核苷酸序列（CDS)相同，但编码胰岛素的DNA序列不同．各物种胰岛素原蛋白质序列中，A链和B链序列保守，C肽有一定的差异；DNA序列差异较大．     

Cultivation of malarial parasites.

The method for continuous cultivation of Plasmodium falciparum has now been successfully applied to several strains from different geographical areas. It has been used for tests of antimalarial drugs, for studies of parasite-host cell interactions with special reference to sickle haemoglobin, and for the production of amounts of parasite sufficient for experimental immunisation of Aotus trivirgatus monkeys.     

一种缺失数据的填补方法

分析了在含有遗失值的数据集上如何进行有效的数据填补,以便更客观地反映数据集中数据所隐含的内在联系.通过采用粗糙集理论的有关思想和方法,用相似关系代替粗糙集理论中的不可分辨关系,提出了基于相似关系的填充算法,提高了遗失数据填补的精确度.数据实验表明了该方法的有效性和可行性.