猪繁殖性状的遗传改良策略

猪繁殖性能的提高将为养猪业带来巨大的经济效益 ,目前多数育种者将提高猪的繁殖力作为主要育种目标 ,并用数学遗传学方法和分子育种技术对繁殖性状进行改良。     

城镇化水平计算方法比较分析

城镇化是社会经济发展的必然趋势，与小城镇人口、经济实力、社会发展和环境保护等方面密切相关。城镇化判别指标归纳起来分两大类：一类是单一指标法或称主要指标法；另一类是多项指标法、复合指标法或称综合指标法。在常用的、单一指标法的城镇化水平计算方法中，城镇人口比重指标法和带眷系数法两种方法能够比较准确地反映小城镇的城镇化水平，尤其以城镇人口比重指标法计算结果最符合实际。     

果树技术经济效益评价的程序与方法研究

本文结合果树生产实际,阐述了果树生产技术经济效益评价研究的基本方法、基本程序步骤和各步骤实施的要求,对评价结果的分析方法进行了较为详细的说明。其中包括对比分析法、试算分析法、边际分析法在果树生产技术经济效益评价研究上的应用。同时本文对该课题中所涉及的几个果树技术的经济效益评价方法程序进行了各论。     

一类正规矩阵的反问题

In this paper, we consider the inverse problems for a kinds of normal matrices. Some necessary and sufficient conditions for existence of solution of these problems are given. The expression of the general solution is given.     

耕牛血吸虫病检测方法比较试验

目的为了解几种检测耕牛血吸虫病的敏感性进行本试验。方法将经粪便毛蚴孵化法检出血吸虫病阳性的水牛(6头)，同时进行干卵聚酯薄膜环卵沉淀试验、间接血凝试验及快速诊断试纸盒检验的测试。结果以其检测结果与粪便毛蚴孵化法相比，阳性符合率分别为100％、100％和83％，3种方法间无显著差异。结论快速诊断试纸盒检测法以其操作简便且准确、快速、特异性高的特点，在动物血防普查工作中具有广阔的应用前景。     

丛生竹防霉处理研究

通过选用多种防霉剂,采用不同的处理方法来对丛生竹进行防霉处理,分别进行室内存放1 a后检验和恒温恒湿箱快速检验来判定防霉效果,对几种处理方法的优缺点进行比较,从中筛选出针对不同使用场合处理的优良防霉剂。     

非线性方程组拟牛顿法中线性搜索的一种改进

改进了Ｇｒｉｅｗａｎｋ（１９８６）提出了关于求解非线性方程组的一种线性搜索方式。在理论上保证了线性搜索的实现,使得算法是适定的,而且,在改进的线性搜索条件下,Ｂｒｏｙｄｅｎ算法仍具有全局收敛性和局部超线性收敛性。     

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.     

The influence of sampling scheme and interpolation method on the power to detect spatial effects of forest birds in Ontario (Canada)

Spatial ecology is becoming an increasingly important component of resource management, and the general monitoring of how human activities affect the distribution and abundance of wildlife. Yet most work on the reliability of sampling strategies is based on a non-spatial analysis of variance paradigm, and little work has been done assessing the power of alternative spatial methods for creating reliable maps of animal abundance. Such a map forms a critical response variable for multiple scale studies relating landscape structure to biotic function. The power to reconstruct patterns of distribution and abundance is influenced by sample placement strategy and density, the nature of spatial auto-correlation among points, and by the technique used to extrapolate points into an animal abundance map. Faced with uncertainty concerning the influence of these factors, we chose to first synthesize a model reference system of known properties and then evaluate the relative performance of alternative sampling and mapping procedures using it. We used published habitat associations of tree nesting boreal neo-tropical birds, a classified habitat map from the Manitou Lakes area of northwestern Ontario, and point count means and variances determined from field studies in boreal Canada to create 4 simulated models of avian abundance to function as reference maps. Four point sampling strategies were evaluated by 4 spatial mapping methods. We found mixed-cluster sampling to be an effective point sampling strategy, particularly when high habitat fragmentation was avoided by restricting samples to habitat patches >10 ha in size. We also found that of the 4 mapping methods, only stratified ordinary point kriging (OPK) was able to generate maps that reproduced an embedded landscape-scale spatial effect that reduced nesting bird abundance in areas of higher forest age-class fragmentation. Global OPK was effective only for detecting broader, regional-scale differences. This revised version was published online in July 2006 with corrections to the Cover Date.     

Biological control of cereal seed-borne diseases by seed bacterization with greenhouse-selected bacteria

About 400 bacterial strains, isolated from roots of wild and cultivated plants, were screened for effects against diseases caused by Drechslera teres and/or Microdochium nivale in greenhouse tests and against common bunt caused by Tilletia caries in field tests. Four of the strains showed good biocontrol activity <70% disease reduction) against D. teres and T. caries both in screenings and field tests. One Pseudomonas isolate, MA 342, strongly and reliably suppressed both D. teres and T. caries in the field, while effects against M. nivale were weaker. The effects could not be enhanced by varying pre-application or seed application procedures. This isolate could be stored as a suspension in a refrigerator, frozen or applied to seeds for at least one month without loosing its disease controlling ability.