虚拟现实技术在温室中的应用

虚拟现实技术,即通过计算机等,最有效的模拟人在自然环境中视、听、动等行为的高级人机交互技术。这种技术已被广泛应用于工业、农业、军事、医学、建筑、造船、飞机制造和各种飞行训练等。该文概述了虚拟环境技术国内外研究进展,论述了“虚拟温室”研究的意义、研究的方法、应用以及将来的研究方向。     

21世纪是我国生态经济学更大发展的世纪

回顾了我国生态经济学发展的历史，阐述了生态经济学在我国生态经济建设与可持续发展中的作用，为进一步推动我国生态经济更大发展，提出了今后我国生态经济学的研究方向。     

不同因素对甘薯根系发育的影响

选用3个不同基因型的甘薯品种,采用正交试验设计,研究了百苗重和施肥量对甘薯块根的形成,特别是甘薯块根结薯个数的影响。结果表明,品种、百苗重及施肥量对甘薯根系发育有显著影响,南薯88在百苗重为4.0kg和不施肥条件下其根系重量和块根数量显著优于其他水平,同时南薯88根系数量最高。     

玉米自交系3081在繁殖中存在的问题及对策

内单四号（哲单七号）自1992年审定以来．在内蒙古西部地区广泛种植。成为这些地区的玉米主栽品种．种植面积在13．3多万hm^2，年需种量在500万kg左右。3081作为内单四号的母本。其质量的好坏决定着这一品种的寿命。如何保持3081本身的优良特性，提高其在制种中的纯度．是各种子生产单位需要考虑的问题，笔者就十几年来在3081提纯、复壮以及制种过程中的感受。谈几点看法：     

How much more global warming and sea level rise?

Two global coupled climate models show that even if the concentrations of greenhouse gases in the atmosphere had been stabilized in the year 2000, we are already committed to further global warming of about another half degree and an additional 320% sea level rise caused by thermal expansion by the end of the 21st century. Projected weakening of the meridional overturning circulation in the North Atlantic Ocean does not lead to a net cooling in Europe. At any given point in time, even if concentrations are stabilized, there is a commitment to future climate changes that will be greater than those we have already observed.     

贮温对番茄PE、PPO、CAT、POD活性的影响

本研究旨在通过研究常温与低温贮藏分别对番茄组织内果胶酶(PE)、多酚氧化酶(PPO)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响,为番茄贮藏运输及加工提供理论基础。通过研究得出,PE、PPO、POD、CAT在常温与低温贮藏条件下,随着番茄的成熟与衰老其活性都是前期过程中有升高阶段,而到了后期又呈现下降趋势;低温贮藏的番茄,PE、PPO、CAT、POD活性均低于常温贮藏的番茄;PE活性的变化与绿熟番茄果实硬度的变化基本一致。     

Cleavage of proBDNF by tPA/plasmin is essential for long-term hippocampal plasticity

Long-term memory is thought to be mediated by protein synthesis-dependent, late-phase long-term potentiation (L-LTP). Two secretory proteins, tissue plasminogen activator (tPA) and brain-derived neurotrophic factor (BDNF), have been implicated in this process, but their relationship is unclear. Here we report that tPA, by activating the extracellular protease plasmin, converts the precursor proBDNF to the mature BDNF (mBDNF), and that such conversion is critical for L-LTP expression in mouse hippocampus. Moreover, application of mBDNF is sufficient to rescue L-LTP when protein synthesis is inhibited, which suggests that mBDNF is a key protein synthesis product for L-LTP expression.     

Cleptoparasitism and odor mimetism in bees: do nomada males imitate the odor of andrena females?

Identical chemical compounds are present in the Dufour gland secretion of female Andrena bees and in the cephalic secretion of many male Nomada bees. Females of Nomada parasitize the nests of Andrena. Many Nomada species confine their attacks to a single host species. In two such host-parasite pairs, Andrena haemorrhoa-Nomada bifida and Andrena carantonica-Nomada marshamella, all-trans farnesyl hexanoate was found to be the totally dominant component in respective secretions. In two other pairs, Andrena helvola-Nomada panzeri and Andrena clarkella-Nomada leucophthalma, geranyl octanoate is the major component. This pairwise odor correspondence is discussed in relation to critical points of contact in the life cycles of host and parasite, male and female.     

T型雄性不育小麦种子蛋白的电泳分析

以梯度SDS－PAGE方法分析了T型小麦雄性不育系及其保持系种子醇溶蛋白和谷蛋白组分，发现两系间有明显差异，而且四个不同品种小麦不育系均有各自与保持系区别的谱带出现，表明T型雄性不育小麦醇溶蛋白基因的表达有品种特异性。用单、双向电泳结合银染技术进一步分析了胚乳醇溶蛋白，发现不育系11A和14A，分别有24kD和36kD的特异蛋白。     

微缩景观文化的美学价值初探

微缩景观艺术在我国造园活动中历史久远,形成的门派风格众多,现代微缩景观设计能否将其蕴含的中国传统元素发展应用,是值得关注的一个重要议题。即从微缩景观艺术的意象、微缩景观艺术的美术思想和微缩景观设计的继承与创新等几个方面去探讨微缩景观艺术的美学价值及其应用。