有风险投资与无风险投资组合的研究

本研究通过引入单位风险的概念，并结合有效边界上的单位风险极小点，给出了各种情况下有风险投资和无风险投资的最优组合方案。     

干旱区土地退化生态系统的评价方法

本文简要介绍了我国干旱区的二种分类方法、分布面积和自然特点。干旱区土地生态系统退化的主要类型有草场退化，而养耕地退化和灌溉地退化，国内外各种退化类型的分布面积。提出退化土地生态系统评价原则，主要退化土地的评价指标体系，评价因子权重的确定方法，综合评价方法及地理信息系统的应用。     

Evaluation and mapping of soil erosion susceptibility: an example from Kenya

Abstract. The erosion susceptibility of the Erosion Research Farm at Kabete Campus was mapped using a qualitative parametric method. A grid soil survey of the 4 ha farm was combined with a map of slope gradients, slope segments being delineated by breaks in slope. Rainfall erosivity and soil erodibility were also measured. Areas with the greatest erosion susceptibility according to this method were those occupying convex slope positions and slopes of more than 30%. Field observations and soil loss measurements generally supported the erosion susceptibility rating map produced by this method. The soil and erosion susceptibility maps were useful for planning erosion control measures and for selecting suitable sites for runoff plot experiments.     

农村产业结构的评价与分析

根据农村产业结构调整的目标和评价指标，对河南省农村产业结构进行了评价和分析。结果表明，农村产业结构经过１０ａ的调整，发生了质的变化，但是，农村劳力转移速度和农民收入增长速度远滞后于农村产业结构调整的速度。作者针对存在问题，提出了进一步调整的建议。     

提高农业科技查新工作质量的探讨

本文针对当前农业科研查新检索的现状,结合自身的工作实际,阐述了农业科技查新工作的重要作用。论述了农业科研成果的特点,着重对农业查新的业务受理、文献资源建设、检索策略制定、“零”结果的判断、文献相关性分析、查新报告结论和工作人员素质等环节,探讨如何提高农业科技查新工作质量的措施。     

冷季型草坪草混播配方优化组合筛选研究

在贵州气候条件下,通过对草地早熟禾、高羊茅、多年生黑麦草3种冷季型草坪草不同品种的19种混播配方进行了适应性和成坪品质的详细观察测定,筛选出了适应当地气候条件下的优化组合配方3种。     

Contribution of contact toxicity and wheat condition to mortality of stored-product insects exposed to spinosad

Spinosad, a reduced-risk commercial insecticide derived from a bacterial fermentation product, possesses both contact and oral toxicities against insects. Contact toxicity of spinosad to adults of Rhyzopertha dominica (F), Sitophilus oryzae (L), and Tribolium castaneum (Herbst) was evaluated by exposure for 24 or 48 h to treated glass Petri dishes. Adults were exposed to different deposits (0.001-0.79 mg cm(-2)) of spinosad in 24-h tests and to deposits of 0, 0.0016 and 0.016mg cm(-2) in 48-h tests. Rhyzopertha dominica was most susceptible to spinosad in 24- and 48-h tests, followed by S. oryzae, and T. castaneum. The 24-h LD50 values were 0.0004, 0.077 and 0.189mg cm(-2) for R. dominica, S. oryzae, and T. castaneum, respectively. All R. dominica adults were dead following 48 h exposure to both spinosad deposits, whereas mortality of S. oryzae and T. castaneum ranged from 10 to 85% and 12 to 48%, respectively. Rhyzopertha dominica, T. castaneum, and O. surinamensis adults were exposed for 14 days to whole wheat, cracked wheat and wheat flour treated with 0, 0.1 and 1.0 mg kg(-1) of spinosad. Rhyzopertha dominica adults were highly susceptible to spinosad, followed by O. surinamensis and T. castaneum. Immatures (eggs and larvae) of T. castaneum and O. surinamensis exposed for 14 days were more susceptible on spinosad-treated whole wheat than on treated cracked wheat and wheat flour. This is the first report documenting contact activity of spinosad, and the effect of grain condition on spinosad toxicity, to stored-product insects.     

不同饲用燕麦品种生产性能的综合评价

基于熵权赋权法,运用灰色系统理论中的灰色关联度法对26个燕麦品种的生产性能进行综合评价,结果表明,生产性能综合表现较好的是初岛燕麦、青永久409、青永久709及青永久316;青永久18综合评价值最低,生产性能最差,其余品种生产性能表现一般。经逐步回归分析,发现其中的绿叶数、叶长、茎叶比、鲜干比、生长速度、叶面积指数、相对生长速率及生长天数8个指标对饲用燕麦生产性能贡献显著。     

甘肃省土地资源可持续利用定量评价

从资源、环境、经济和社会4方面构建土地资源可持续利用评价指标模型,并选择23个参评因子,对甘肃省土地资源可持续利用空间差异进行定量分析,发现甘肃省土地资源可持续利用水平有明显的空间差异,认为各地在资源开发、经济发展、社会进步和环境保护方面有待进一步协调。     

退耕还林政策实施对退耕者经济纯效益的影响评价——以甘肃4个退耕还林试点县为例

在总结前人对退耕还林政策实施效果评价的基础上,从退耕者所得到的经济效益角度,评价退耕还林政策的方法,并以甘肃4个退耕还林试点县为例进行实证研究.具体步骤为:首先,构建评价所需的指标体系,然后通过实地调查得到所需指标数据,再运用费用效益法估算政策实施前后退耕者所得纯经济效益.最后,运用比较分析法对比政策实施前后退耕者所得纯经济效益的大小,从而实现退耕还林政策对退耕者经济纯效益的影响评价.