新疆莎车县棉田自然天敌数量动态

2002-2004年研究了新疆莎车县棉田节肢动物类自然天敌种群动态及棉花品种的影响。结果发现节肢动物类自然天敌67种,数量较多的共10类,即瓢虫类、蝽类、隐翅虫类、蓟马类、草蛉类、食蚜双翅目、胡蜂类、蚜茧蜂类、蜘蛛类和捕食螨类。其中瓢虫类、蝽类和蜘蛛类占天敌个体总数85%~93%。3年中这三类天敌各自所占比例,瓢虫为4%~65%,食虫蝽为19%~57%,蜘蛛为6%~34%。瓢虫、食虫蝽和蜘蛛的最高密度2002年分别为237.2、164.0、87.0头/百株,2003年分别为28.3、533.3、232.0头/百株,2004分别为1506.5、237.0、55.3头/百株。对转基因抗虫棉GK19(表达Cry1A杀虫蛋白)、SGK321(表达Cry1A CpTI杀虫蛋白)和普通棉花泗棉3号、石远321的研究表明,各种天敌在不同品种上的种群数量没有显著性差异,而喷施化学农药可以造成天敌数量明显减少。     

不同地域长爪沙鼠群体间遗传状况分析

应用27个生化基因位点,分别对首都医科大学实验动物科学部和浙江省实验动物中心饲育的2个长爪沙鼠群体进行了遗传分析。结果显示,首都医科大学实验动物科学部长爪沙鼠群体遗传适应性、遗传多样性水平、遗传变异程度都明显高于浙江省实验动物中心沙鼠群体（P〈0.05）,并且这2个沙鼠群体间未出现较为明显的遗传分化（FST〉0.05）。     

抗菌肽的研究与应用

抗菌肽具有分子量小、热稳定性好、无免疫原性、抗菌谱广等特点；并且，抗菌肽对畜禽具有促生长、保健和治疗疾病等功效；具有无毒副作用、无残留、无致细菌的耐药性等特性；在动物养殖和提高畜产品品质方面，抗菌肽也具有重要的潜在应用价值。文章结合当今抗菌肽的研究现状和发展前景，对抗菌肽的分类、抗菌机理、应用状况等进行了综述。     

Estradiol stimulated proliferation and differentiation of prostatic stromal cells through regulation of BPH-1 paracrine

AIM: To characterize the effect of estradiol on proliferation, differentiation and extracellular matrix (ECM) accumulation in stromal cells through regulation of BPH-1 paracrine. METHODS: BPH-1 cells were stimulated with different concentrations of estradiol. Conditioned media (CM) were harvested and their effects on stromal cell cultures were tested. Cell proliferation was determined by MTT assay. mRNA of smoothelin, fibronectin, collagen Ⅳ and transforming growth factor β₁(TGF-β₁) were analyzed by real-time RT-PCR. Western blotting was used to determine smooth muscle myosin heavy chain (SMMHC). ELISA and radioimmunoassay were respectively used to measure fibronectin, TGF-β₁ and collagen Ⅳ protein expressions.RESULTS: Estrodiol stimulated the expression and secretion of TGF-β₁ in BPH-1 cells. The proliferation of stromal cells increased when they were cultured with CM harvested from estrogen treated BPH-1 cells. The mRNA levels of collagen Ⅳ and smoothelin increased in stromal cells treated with CM from BPH-1 cells. The results of radioimmunoassay also showed that the collagen Ⅳ protein level up-regulated in the supernatants and cell extracts of CM-treated stromal cells. A neutralizing antibody to TGF-β₁ inhibited the stimulation of collagen Ⅳ and SMMHC by BPH-1 CM. The expression of fibronectin was only marginally changed in stromal cells cultured in the presence of BPH-1 CM. CONCLUSION: The BPH-1 cells increase ECM accumulation and differentiation of stromal cells through TGF-β₁. Estradiol stimulate differentiation of stromal cells by induction of TGF-β₁ expression. Estradiol stimulate proliferation by influencing the factors secreted from prostatic epithelial cells.     

黄土高原梯田质量评价系统设计研究

针对黄土高原的自然环境条件，提出了梯田质量评价的指标体系、评价系统的设计原则及方法。探讨了梯田质量评价系统的主要模块，研究了梯田数据库的结构及主要内容，利用VisualBasic6．0与MapX5．0相结合，开发了黄土高原梯田质量评价信患系统，实现了属性信息与空间信患的相互查询、统计分析以及对梯田质量进行评价。本系统的建立能够对梯田建设与管理提供科学依据，为黄土高原水土保持工作提供基础资料，具有一定的社会和经济效益。     

SCARA并联机构拓扑分析与其低耦合度机型设计

根据基于方位特征(Position and orientation characteristics,POC)的并联机构拓扑结构设计理论与方法,首先,对已提出的一类7个具有较好实用价值的SCARA并联机构,进行了拓扑结构分析,揭示了其POC集、自由度(含驱动副选取)、过约束数、耦合度以及输入-输出运动解耦性等5个最主要的拓扑特征,且发现这些机构的耦合度均较大,为2,表明其运动学正解和动力学求解十分复杂;继而基于机构拓扑结构降耦原理,又对κ=2的这7个机构进行了拓扑结构降耦优化,得到了低耦合度(κ=1),而机构POC、自由度(Degree of freedom,DOF)等保持不变的实现SCARA运动的14个新机型,不仅丰富了实现SCARA运动的4-DOF三平移一转动机型库,而且降低了这些机构的运动学和动力学代数求解难度,而其数值解可用一维搜索法方便求得,从而为这一类SCARA并联机构的运动学和动力学分析、设计及应用提供了理论基础。     

Effects of AMF inoculation on growth of Panax ginseng C.A. Meyer seedlings and on soil structures in mycorrhizosphere

We aimed to investigate the effects of inoculating Panax ginseng C.A. Meyer seedlings with arbuscular mycorrhizal fungi (AMF) by examining the root colonization, plant nutrition uptake, growth characteristics, and soil aggregation of P. ginseng seedlings inoculated at the time of transplantation. At 16 weeks, the AMF spore density per 30 g of fresh mycorrhizosphere in seedlings inoculated with AMF (AMF+ seedlings) was 256.8 and that in seedlings not inoculated with AMF (AMF− seedlings) was 186.3, respectively. The colonization rate of AMF in the lateral roots of AMF+ seedlings was approximately 19% higher than that in the lateral roots of AMF− seedlings. The patterns of AMF colonization in ginseng roots were similar to those of the Paris-type mycorrhizal association. Plant growth characteristics, such as plant height, root length, leaf area, number of lateral roots, fresh weight of shoots and roots, and chlorophyll content, were significantly enhanced in AMF+ seedlings compared to AMF− seedlings. The macronutrient content (P, K, and Ca) and micronutrient content (Cu, Fe, and Zn) of both shoots and roots were also significantly higher in AMF+ seedlings compared to AMF− seedlings. Furthermore, glomalin content and soil aggregation were significantly enhanced in AMF inoculated areas. Our results indicate that AMF inoculation may enhance the growth of ginseng seedlings by improving the uptake of mineral nutrients and the soil structure in mycorrhizosphere.     

变量筛选方法对郁闭度遥感估测模型的影响比较

比较基于偏最小二乘回归的Bootstrap方法与传统的平均残差平方和(RMSq)准则所选变量建立模型的精度差别.结果表明:Bootstrap方法是一种更优秀的变量筛选方法,比RMSq方法精度提高约5%;而且它不受变量多带来的运算困难的限制,更便于实际应用.