古巴非洲猪瘟根除的经验与借鉴

1971年非洲猪瘟首次传入古巴并于当年根除,1980年再次传入并在一年内又被根除。古巴能快速根除非洲猪瘟,主要与防控专业委员会的及时成立,协作机制的快速建立;全面扑杀措施的快速实施,健康猪产品的合理利用;民间团队的积极参与以及政府财政的大力支持密切相关。古巴的根除经验,可为我国非洲猪瘟的防控提供参考。     

北方寒地引种抗寒苜蓿品种试验

１９９１、１９９２年两年对１０个抗寒苜蓿品种进行了品种比较试验，鉴选出公农一号、草原一号、草原二号、甘农一号、图牧二号６个苜蓿良种。这些品种适应黑龙江垦区的生态条件，抗寒、抗病性强、长势好、产草量高、品质优良，可以在垦区三江平原推广种植。     

昆虫黑化反应的分子机制研究进展

目的克氏原螯虾(Procambarus clarkii)属于节肢动物门甲壳纲十足目,也称淡水小龙虾。多巴脱羧酶(dopa decarboxylase)作为小龙虾先天免疫应答中的一种关键酶,在抵御外来病原体的侵害上起到了重要作用。本研究以克氏原螯虾为材料,克隆了Pc-ddc cDNA序列并对其进行生物信息学及组织mRNA表达分析。方法通过分子生物学技术构建大肠杆菌表达载体,并进行生物信息学分析,同时应用qRT-PCR技术分析其mRNA组织表达分布。结果生物信息学分析表明：获得了开放阅读框全长为1 425 bp的Pc-ddc基因的cDNA序列,编码474个氨基酸残基,多肽的理论分子量为52.99 ku,蛋白分子式为C₂₃₈₄H₃₆₈₉N₆₄₇O₆₇₄S₂₅,等电点为5.98,为弱酸性蛋白且N-末端无信号肽。亚细胞定位表明：Pc-DDC蛋白在线粒体中最多;组织表达分析表明：Pc-ddc mRNA在检测的6个组织中差异表达,其中,淋巴组织表达量最高。结论本研究为克氏原螯虾等无脊椎动物先天免疫系统的深入探索提供了理论支撑。     

Estimating spatial mean soil water contents of sloping jujube orchards using temporal stability

Estimating spatial mean soil water contents from point-scale measurements is important to improve soil water management in sloping land of semiarid areas. Temporal stability analysis, as a statistical technique to estimate soil water content, is an effective tool in terms of facilitating the upscaling estimation of mean values. The objective of this study was to examine temporal stability of soil water profiles (0–20, 20–40, 40–60 and 0–60 cm) in sloping jujube (Zizyphus jujuba) orchards and to estimate field mean root-zone soil water based on temporal stability analysis in the Yuanzegou catchment of the Chinese Loess Plateau, using soil water observations under both dry and wet soil conditions. The results showed that different time-stable locations were identified for different depths and the temporal stability of soil water content in 20–40 cm was significantly (P < 0.05) weaker than that in other depths. Moreover, these time-stable locations had relatively high clay contents, relatively mild slopes and relatively planar surfaces compared to the corresponding field means. Statistical analysis revealed that the temporal stability of root zone soil water (0–60 cm) was higher in either dry or wet season than that including both, and soil water exhibited very low temporal stability during the transition period from dry to wet. Based on the temporal stability analysis, field mean soil water contents were estimated reasonably (R² from 0.9560 to 0.9873) from the point measurements of these time-stable locations. Since the terrains in this study are typical in the hilly regions of the Loess Plateau, the results presented here should improve soil water management in sloping orchards in the Loess Plateau.     

复配材料超声处理对化肥控失效果的影响

利用超声波对化肥控失材料(LCM)进行修饰改性,结果表明对硫酸铵的控失效果随处理时间呈现先升高然后降低的规律,峰值出现在5min.本文对其机理进行初步探讨.     

EXPERIMENTAL RESEARCH ON VISCOELASTICITY OF HUMAN BLOOD- WITH REFERENCE TO THE EFFECT OF CELL HEMOTOCRIT

This paper describes a part of the experiments concerning the viscoelasticity of human blood, which are based upon the theories lead by the authors. The data from the experiments are compared with those in the literatures. The effect of cell hematocrit on viscoelasticity is especially discussed and a new viscoelasticity index is defined to eliminate this effect.     

A Study on the Mathematical Models for Two Dimensional Guillotine Cullting-stock

Based on the analysis and study on some existed models for two-dimensional Guillotine Cutting-Stock problem, it is pointed out that some kinds of the models may miss some good cutting patterns,and some may result in inadequate solutions because of only considering the patterns with the smallest waste. A kind of revised two-dimensional cutting-stock models are developed,which transform the two-dimensional problem into the one-dimensional one using the dimension-decreasing heuristic method and whose initial patterns are considered comprehensively. In this kind of models, not only the least waste,but also the other constraints,such as the demands and the relative area of the order plates are considered.     

柴油机台架试验中综合指标的建立与应用

介绍了正交试验中多指标分析法,建立了柴油机综合性能指标并阐述了其在试验分析中的应用。     

权变理论在灌区管理中的应用

权变理论是当前西方管理学中一种较流行的理论。在介绍了权变理论基本思想的基础上，探讨了权变理论在灌区产权制度改革、经营管理模式、水费计收、用水管理等领域的应用，强调灌区管理水平的高低取决于灌区管理与其外部环境和内部环境的适应性。