不同稀释液对藏獒精液保存效果的影响

比较了8种稀释液在藏獒精液冷冻保存和低、常温保存(5 ℃,10 ℃,15 ℃,20 ℃)的效果.结果表明:2号和8号稀释液在冷冻保存时效果最好,精子活力和顶体完整率分别达到0.40和49%,与对照组相比差异显著(P<0.05).在藏獒的低温、常温保存试验中,所有稀释液在15 ℃时保存时间最长,综合考虑,7号液保存效果最好;在15℃时精子平均存活时间为103 h,显著高于对照组和其它稀释液(P<0.05).     

新的信息资源环境下图书馆员角色转变的思考

本文分析了信息时代图书馆员角色转变的几个重要因素及特点,揭示了新时代图书馆员应承担的几种重要角色,对信息时代图书馆员的发展进行了探讨.     

国有林场改革路径选择与对策分析

文章论述了国有林场的建立与发展过程，提出了国有林场面临的主要问题和改革路径选择与对策分析。     

鼠李糖制备新工艺研究

采用正交设计方法探讨发酵法从芦丁水解液里提取制备鼠李糖的最佳制备工艺,优选出鼠李糖纯度达到99%以上的最佳制备工艺为:温度30℃,pH值5.0,酵母量为母液的2%。     

试论工科院校大学生的审美教育

工科院校在强调专业教育的同时，没能同样重视审美教育。加强对工科院校大学生的审美教育，有助于培养正确的审美观，提高审美能力;有助于完善知识结构，提升人文精神; 有助于形成独立完善的人格，提升人格境界;有助于培养个性和谐、德智体美全而发展的高素质人才。     

S1核酸酶突变检测法的优化

优化了S1核酸酶突变检测体系,结果表明(1)扩增法比杂交法产生异源双链DNA更节省时间;(2)PCR产物可以直接作为突变检测的底物;(3)适当降低反应温度、适当增加反应缓冲液中的NaCl浓度、适当缩短反应时间可提高突变检测效果。     

益生素预防畜禽腹泻机理的研究

用革兰氏阳性的嗜酸乳杆菌和枯草杆菌的活菌和死菌喂饲了８０只雏鸡，用嗜酸乳杆菌的活菌和死菌喂饲了３７头仔猪和２４头犊牛，观察这些细菌防畜禽腹泻的效果。结果证明这两种细菌的活菌与死菌都有预防腹泻的功能，嗜酸乳杆菌的效果好于枯草杆菌。两种菌的活菌和死菌都有预防作用说明是菌体成分或代谢产物可能是预防腹泻的主要有效成分。     

桃需冷量遗传特性的研究

对桃的９个杂交组合４６３株杂种实生苗需冷量进行测定,统计结果表明：桃需冷量是由多基因控制的,Ｆ＿１需冷量平均值较亲中值短,不同组合偏离程度不同,南山甜桃、红日、玛丽维拉、白凤、大久保需冷量育种值分别为１５９、２１６、３１９、８３１、８３４ｈ,遗传传递力分别为７９%、５４%、９２%、８３%、９３%。需冷量的遗传力为８９．６９%。萌芽开花与需冷量密切相关。     

Factors influencing decline in soil pH in Hawaiian Eucalyptus and Albizia plantations

Soil pH declined from 5.9 to 5.0 in 8 years beneath plantations of Eucalyptus saligna (Sm.) in Hawaii. In stands of Albizia falcataria, (L.) Fosberg, the soil pH change was more dramatic, declining from 5.9 to 4.6. We measured several components of soil acidity beneath four mixtures of the two tree species to gain insight on the processes responsible for the decline in soil pH. These components were studied using an empirical method of comparing acid quantity, degree of neutralization (depletion of base cations), and acid strength. The decline in soil pH differed between species as a result of differences in the degree of neutralization of the soil exchange complex; the larger decrease in soil pH under Albizia was produced by greater acidification of the exchange complex. Empirical titration curves suggested that differences in acid strength moderated the divergence in soil pH beneath the species. Had the acids accumulating in the soil under Albizia been as strong as those in the Eucalyptus soil, the difference in soil pH would have been greater. Though the two species had contrasting effects on soil pH, the differences in degree of neutralization, responsible for the pH decline, were small compared with differences in the amount of cations stored in tree biomass. Continued supply of nutrient cations (from weathering or fertilization) will ultimately control both the extent of soil pH decline and the level of productivity sustained by the forest.