Cooperative breeding for the northern marginal areas

Summary A joint breeding project for the northern areas of Scandinavia and Iceland was initiated in 1981 under the auspices of the Nordic Council of Ministers. Initially, efforts concentrated on cooperative trials in which both early and more advanced breeding material was tested at a number of experimental stations in the northern regions. This was followed by a joint breeding programme for timothy with the primary aim of developing varieties that possess broad adaptation to a range of Nordic climates and managements and can be grown throughout the northernmost part of Scandinavia. Each of the five national breeding stations originally provided 12 timothy genotypes for the project giving a total of 60 genotypes. The parental genotypes were compared as spaced plants at all five stations and their polycross progeny were grown under sward conditions at the same sites. On the basis of results obtained from these field trials parent clones have been selected and intercrossed to form synthetic populations.     

百花山山地土壤中有机质的垂直分布规律

本文测定了北京百花山山地典型土壤剖面各发生层的有机质含量、腐殖酸组分、可见光谱,利用相关分析方法计算了有机质与海拔高度之间的相关系数。结果表明:有机质与海拔高度的相关系数为0.94,,呈显著相关水平;各剖面土壤腐殖质分析结果表明,该山地土壤的HA/FA值、E4/E6值随着海拔高度的升高而呈现上升趋势。     

基于Master CAM和Pro/E的齿轮快速精确建模及仿真分析基于MasterCAM和Pro/E的齿轮快速精确建模及仿真分析

以外啮合直齿圆柱齿轮为例,介绍了利用Master CAM和Pro/E进行齿轮精确建模,并根据实际工况条件,采用Pro/E的Mechanica对所设计的齿轮进行仿真分析。结果表明,采用此方法可快捷、精确地完成齿轮类零件的设计。     

Anti-inflammatory activities of cucurbitacin E isolated from Citrullus lanatus var. citroides: role of reactive nitrogen species and cyclooxygenase enzyme inhibition

The in vivo and in vitro mechanistic anti-inflammatory actions of cucurbitacin E (CE) (Citrullus lanatus var. citroides) were examined. The results showed that LPS/INF-γ increased NO production in RAW264.7 macrophages, whereas L-NAME and CE curtailed it. CE did not reveal any cytotoxicity on RAW264.7 and WRL-68 cells. CE inhibited both COX enzymes with more selectivity toward COX-2. Intraperitoneal injection of CE significantly suppressed carrageenan-induced rat's paw edema. ORAC and FRAP assays showed that CE is not a potent ROS scavenger. It could be concluded that CE is potentially useful in treating inflammation through the inhibition of COX and RNS but not ROS.     

保水剂对巨尾桉盆栽苗木生长的影响

为评价保水剂在桉树生长中的作用,研究了2种保水剂用量和4种水分供应条件下,巨尾桉苗木的生长量、净光合速率、蒸腾速率和叶绿素含量的变化情况.结果表明,随着田间持水量增加,除了叶绿素含量差别不大,苗木的高增长量、地径增长量、净光合速率均显著上升;施用保水剂的效果与田间持水量60％和80％处理的作用基本一致,保水剂在桉树人工...     

实体水-虚拟水"二维三元"耦合流动理论基本框架

在变化环境下,区域水资源系统演变规律正在发生深刻变化。解决新形势下出现的水问题单单依靠传统的实体水资源规划、调度和调控手段还不够。虚拟水概念和理论的提出拓展了水文水资源的认知范畴,丰富了水问题的解决手段。然而,如何搭建虚拟水理论与传统水文水资源认知体系的统一框架,认识自然-经济-社会连续系统中水资源演化的新规律,目前学界还没有成熟统一的看法。该文首先提出了实体水-虚拟水耦合流动效应的基本理论框架,指出实体水-虚拟水耦合流动是现代环境下自然-经济-社会水资源系统呈现的新特征。其次,从文明进步和生产力发展角度,论述了人类社会水文水资源系统的演化历史,将水文水资源系统演进大体分为三个阶段:早期的实体水"一维一元"自然循环阶段,近现代的实体水"二元"水循环阶段和当前的实体水-虚拟水"二维三元"耦合流动阶段。最后,该文详细论述了实体水-虚拟水耦合流动过程的路径结构,并针对其流动过程和状态表征提出了定量表达方程,初步构建了实体水-虚拟水耦合流动基本理论框架。     

Development of HRB500E seismic grade rebars by using VN microalloyed and controlled cooling process

In order to reduce the production cost of HRB500E seismic grade rebars, promote its production and application, HRB500E seismic grade rebars are developed by using VN microalloyed and controlled cooling process in domestic steel plant. The mechanism and effect of precipitation strengthening and fine-grain strengthening, the relationship between termination temperature after controlled cooling and mechanical properties of rebars, microstructure, welding and aging properties, high-strain and low-cycle fatigue properties for rebars are researched by using metallographic microscopy, scaning electron microcopy, transmission electron microscopy, X-ray diffraction apparatus, flash-butt welding, materials testing machine and mechanical properties testing. The results show that V(C,N) precipitation amount accounts for 66.67% of the total amount of vanadium by adding VN alloy in liquid steel, effect of microalloy precipitation strengthening is remarkable; when termination temperature after controlled cooling is controlled at 680～710 ℃, the amount of strength surplus for rebars is more than 25 MPa, R m/ R eL ratio is greater than 1.26, uniform elongation ( A gt) is more than or equal to 11.5%, good effect of fine grain strengthening and seismic performance are obtained; rebars have some good features such as low strain aging, good welding performance, high-strain and low-cycle fatigue properties; compared with VN microalloyed and hot-rolled process,the production cost is reduced by RMB 82 Yuan/t, and economic benefit is obvious.     

麦科隆对大肠杆菌攻毒仔猪保护率及治疗效果试验

选择断奶1～10d杜长大三元杂交仔猪90头,按随机区组设计分为3组,A组(麦科隆预防试验组)、B组(麦科隆治疗试验组)、C组(青霉素治疗对照组)各30头。通过20d试验,在用致病性大肠杆菌攻毒后,A组发病率为20.00%,比未进行保护的B,C两组的66.67%,70.00%分别下降了46.67和50.00个百分点,差异极显著(P<0.01)。治愈率A组为100%,比B,C两组的91.13%和90.05%分别提高8.87和9.95个百分点,差异显著(P<0.05)。B,C两组比较,差异显著(P<0.05)。死淘率A组为0,B,C两组分别为4.67%和10.53%,A组与B,C两组比较,差异极显著(P<0.01)。B,C两组相比,差异显著(P<0.05)。说明麦科隆微生物制剂对大肠杆菌具有良好的预防和治疗作用,是抗生素的有效替代品。     

啤酒酵母甘露聚糖的提取及其对鸡肠道微生物区系的影响

研究了甘露聚糖复合物的提取技术,确立了该复合物的制备工艺,分析了甘露聚糖的化学组成.结果表明,该复合物是含蛋白质的多糖,其蛋白质的氨基酸组成具有明显的特征性,苏氨酸和丝氨酸的含量较高,而蛋氨酸相对较少.在饲料中添加MOS饲喂雏鸡至第10日,可使粪便中的大肠杆菌数量显著降低(P＜0.05),而乳杆菌数量极显著提高(P＜0.01).     

融合蛋白VP4-STI的免疫效果观察

为了研究融合蛋白VP4-STI的免疫效果。将40只小鼠随机分为实验疫苗组(30μg VP4-STI+0.6μg LTB)、铝胶疫苗组[30μg VP4-STI+Al(OH)3胶]、纯化蛋白VP4-STI疫苗组(30μg VP4-STI)和PBS对照组,通过鼻腔滴入进行免疫,测定其抗体水平。用大肠杆菌强毒株C83902进行攻毒试验,观测各免疫组小鼠的保护效果。除PBS对照组外,其余各组均有抗VP4-STI抗体产生,第6周最高,铝胶疫苗组的抗体水平略高于实验疫苗组,纯化蛋白VP4-STI免疫组较低,与实验疫苗组差异极显著(P<0.001)。实验疫苗组和铝胶疫苗组小鼠对大肠杆菌强毒株C83902均有较好的免疫保护效果,与对照PBS组有明显差异。该研究为进一步提高STI的免疫原性提供了依据。