家畜体外受精技术与研究方法

本文综述了家畜体外受精技术的研究方法和意义,着重介绍了体外受精技术流程、技术要,最和操作手法,简述了家畜体外受精主要技术内容的理论基础,并展望了牛体外受精技术的发展前景。     

Efficacy of Different Control Methods Applied Separately and in Combination in Managing Root-knot Nematodes (Meloidogyne spp.) in Common Beans

Investigations on the efficacy of various methods of managing root-knot nematodes in microplots and under field conditions revealed that soil solarization, Furadan 5G and Tagetes erecta applied separately or in combination with other control methods, were the most effective in reducing the numbers of three root-knot nematodes, and root gall and egg mass indices. These management methods also resulted in significant increases (P0.05) in number of pods per plant, number of seeds per pod and 100-seed weight, and increased seed yield by up to 96.7 percent. Farmyard manure and Crotalaria ochroleuca were the least effective treatments. The use of T. erecta was the most economical root-knot nematode control method.     

城市输配水管网水质变化模型及其数值方法

论述了水质在管网中变化的稳态和动态数学模型，分别给出了求解稳态模型的方法和用拉格朗日法求解动态模型的典型数值方法。     

应用采食模式改进蛋鸡饲喂制度研究

用40周龄 ISA 蛋鸡2116只,随机分为试验组和对照组,同幢鸡舍的2492只为大群组,根据基础日粮,均日喂二次,大群组日喂基础日粮四次,以研究对蛋鸡的影响。结果表明,试验组与对照组的产蛋率、蛋重及蛋的品质均无显著差异,但试验组的饲料成本减少14.74％,主要营养素蛋白质、能量和氨基酸的消耗也分别降低2.17％、2.92％和12.88％。作者认为,蛋鸡对饲料中营养素的利用能力,可能存在“时间节律”性因素的影响。     

Serum 5'nucleotidase activity in rats: a method for automated analysis and criteria for interpretation

A manual kit for determining serum 5'nucleotidase (5'NT, EC 3.1.3.5) activity was adapted for use with rat samples on a large discrete clinical chemistry analyzer. The precision of the method was good (within-run C.V. = 2.14%; between-run C.V. = 5.5%). A comparison of the new automated method with a manual and semi-automated method gave regression statistics of y = 1.18X -3.66 (Sy. x = 4.54), and y = 0.733X + 1.97 (Sy. x = 1.69), respectively. Temperature conversion factors provided by the kit manufacturer for human samples were determined to be inaccurate for converting results from rat samples. Analysis of components contributing to normal variation in rat serum 5'NT activity showed age and sex to be major factors. Increased serum 5'NT activity was observed in female rats when compared to male rats beginning at about 5 to 6 weeks of age. An analysis of variance of serum 5'NT, alkaline phosphatase, and GGT activities observed over a 9-week period in normal rats suggests several advantages for 5'NT as a predictor of biliary lesions in rats.     

小型通用汽油机排放的研究

以168F汽油机为样机,通过改变点火提前角和混合气浓度供给实测了样机的功率、油耗和排放数值。通过发动机示功图采集和放热规律计算,研究了点火提前角和混合气浓度对样机工作过程的影响,探讨了与样机匹配的点火提前角和混合气浓度的最佳值。通过上述试验研究和理论分析,在不使用尾气催化转化器的情况下,使得样机达到EPA第二阶段排放限值,并且具有达到EPA第三阶段排放限值的潜力。     

我国海钓基地建设推进路径的探讨

在当前我国海钓产业兴起之时,基地建设已被列入沿海资源型旅游城市开发利用海钓资源的实事项目之一,如何从理论与实践上解决破坏性建设与重复建设的问题成为当务之急。本文试图从基地建设的产业基础条件研究着手,通过对基地生态、环境影响要素条件的评价,结合具体实证规划研究成果,在国内业界首次提出了海钓基地建设推进路径的全新观点。认为,建立岛礁生物资源保护的长效机制是完善和保障产业基础的最主要途径;实施海洋游钓资源生态补偿制度,是实现基地建设可持续发展的基本对策。     

A model calculation approach towards the optimization of a standard scheme of seed‐parent line development in hybrid rye breeding

The importance of hybrid rye (Secale cereale L.) breeding has steadily increased over the last decades. This paper presents results of model calculations aiming to optimize the number of candidates, testers to assess combining ability and test locations at each selection stage of a standard scheme of seed‐parent line development. Two variants of the scheme differing in the number of stages and the cycle length are investigated. Optimization criterion is the expected selection gain per year under the restriction of a fixed budget. Prediction of selection gain rests on quantitative–genetic and economic parameters estimated from breeders’ data. Optimization covers different genetical and economical situations. Results show that the optimum number of testers to assess combining ability depends on the relative amount of dominance variance. The efficiency of a breeding scheme strongly increases with decreasing cycle length. A larger budget should mainly be used to increase the number of candidates at all selection stages. Recommendations for practical breeding schemes are given. We conclude that model calculations are a valuable tool for the optimization of breeding schemes.     

大学生思想政治教育方式方法创新的四维视角——基于增强亲和力感染力的思考

基于增强思想政治教育亲和力感染力的思考,从和谐教育关系、拓展教育渠道、着眼接受偏好、发挥＂双主体＂能动性等四维视角,探究思想政治教育方式方法创新,提出思想政治教育同构式方法、渗透式方法、网络式方法、体验式方法等,并分析了其实现的路径。     

新形势下高等职业教育实践教学形式的改进研究

本文对21世纪新形势下如何改进高等职业教育的实践教学形式进行了一些探讨,对提高高等职业教育实践教学效果、培养高素质的应用型人才有一定的借鉴作用。