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.     

西安地区草坪杂草的种类、危害及其防治

通过对西安地区草坪杂草种类与多度的调查、统计和分析，发现48种草坪杂草，隶属23科，草坪杂草一年生杂草29种，多年生杂草19种，其中禾本科杂草8种，占杂草总数的17％，菊科12种，占杂草总数的25％。提出春季草坪建趔地，为避免杂草危害应以早春种植为宜，对杂草防治应选用适合当地生长的草坪草种为宜等。     

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.     

木瓜属(Chaenomeles)栽培品种与近缘种的数量分类

选取木瓜属(Chaenomeles)18个栽培品种和4个近缘种的24个形态学性状,利用SPSS10.0软件进行聚类分析,以探讨品种间的亲缘关系。Q型聚类分析显示供试样本可分为2类：木瓜和‘豆青’自成一类,与其他种类和品种关系疏远;其余种类和品种聚合成一类。而第2类分为4个亚类,贴梗海棠、木瓜海棠、倭海棠以及5个杂交品种分别聚合。根据聚类结果,‘猩红与金黄’和‘碧雪’等品种的分类地位值得进一步探讨。数量分类结果能够反映品种之间的亲缘关系。R型聚类结果表明,各分类性状之间没有明显的逻辑关系,24个形态学性状对品种的演化具有较独立的意义。主成分分析表明,前6个主成分的累计贡献率达85.9%,根据其与性状间的相关性可知,影响力较大的性状有花径、花梗颜色、花瓣形状、花瓣宽、瓣爪长、幼叶颜色、花托和果实形状、重瓣性和花瓣数目等。     

海南优势海草营养元素的含量及其影响因素研究

研究了海南新村港、黎安港、文昌和琼海（潭门）等地的优势海草种类海菖蒲(〖WTBX〗Enhalus acoroides〖WTBZ〗)、海神草(〖WTBX〗Cymodocea rotundata〖WTBZ〗)及泰来藻(〖WTBX〗Thalassia hemperichil〖WTBZ〗)中氮、磷及铁的含量和影响因素.研究结果表明,海南潮间带海草对养分的吸收与海水营养水平及沉积物氮、磷、有机碳、铁有关.相对于氮,海草叶片磷含量受海水和沉积物的影响更明显.海水磷、沉积物有机碳和铁均能促进海草组织对磷的吸收.海草叶片的氮磷比为新村港（21.73）>黎安（14.25）>文昌（9.53）≈潭门（10.29）,与海水中溶解性总氮和溶解性无机磷的比值呈线性正相关,说明海水的富营养化影响了海草叶片的氮磷平衡.