三阶时滞泛函微分方程解的渐近性

本文讨论一类三阶时滞泛函微分方程解的渐近性质,给出了若干解的有界性及解趋于零的判定准则.     

混合变元中立型微分方程的解的振动准则：献给李森林教授八十寿辰

本文得到了两类混合变元中立型微分方程的解的某些新的振动准则,大大改进了〔[5,7-9〕的结果.并推出了变系数的混合中立型方程.     

超临界增长椭圆方程组广义解的正则性

In this paper, the author proved the partial regularity of the generalized solutions of the super critical growth elliptic system. Furthermore, the everywhere regularity of generalized solutions of three special systems are obtained.     

牵引犁受力分析的解析方法

分析了牵引犁受力图解法求解所存在的问题，用解析方法建立了牵引犁受力的矩阵方程组并利用计算机进行了求解，预测了各结构参数变化对机组受力工况的影响，从而为牵引犁机组的合理配置和各部件结构的强度计算和优化设计提供了理论依据。     

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。     

西杂牛连续埋植“畜大壮”效果观察

本试验对甘肃河西地区西杂１－２岁和周岁以下的犊牛连续用促生长剂“畜大壮”分阶段进行耳根埋植,试验结果表明,４－６月龄犊牛全期１８０天,试验组增重和平均日增重分别为５．５ｋｇ和３０８．３３ｇ,试验组比对照组提高３７．２５ｋｇ和２０６．９４ｇ（Ｐ〈０．０１）,１－２岁牛全期１８０天,试验组平均增重和日增重分别为５６．４３ｋｇ和３１４．４９ｇ,试验缄比对照组分别提高３０．０３ｋｇ和１６６．８２ｇ差异显著     

The effects of azadirachtin and nucleopolyhedrovirus on midgut enzymatic profile of Spodoptera litura Fab. (Lepidoptera: Noctuidae)

The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spodoptera litura Fabricius (Lepidoptera: Noctuidae) (Tobacco cutworm) were evaluated. Gut enzyme activities were decreased by AZA and NPV individually and in combination. When S. litura larvae were fed a diet of castor leaves treated with AZA and NPV in bioassays, gut enzyme—acid phosphatases, alkaline phosphatases, adenosine triphosphatases, and lactate dehydrogenase—activities were decreased. There were statistically significant differences (P ? 0.05) in enzyme activities between combined and individual treatment. A synergistic effect of botanical insecticides and virus was found when combined in low doses. These effects are most pronounced in early instars. Maximum weight loss (59-72%) occurred, when AZA and NPV were combined.     

Modelling Plant Disease Epidemics

An epidemic is the progress of disease in time and space. Each epidemic has a structure whose temporal dynamics and spatial patterns are jointly determined by the pathosystem characteristics and environmental conditions. One of the important objectives in epidemiology is to understand such spatio-temporal dynamics via mathematical and statistical modelling. In this paper, we outline common methodologies that are used to quantify and model spatio-temporal dynamics of plant diseases, with emphasis on developing temporal forecast models and on quantifying spatial patterns. Several examples of epidemiological models in cereal crops are described, including one for Fusarium head blight.     

Meta‐analysis of the energy and protein requirements of hair sheep raised in the tropical region of Brazil

The objective of this study was to estimate, through mathematical models, energy and protein requirements for maintenance and gain of hair sheep raised in the tropical region of Brazil. To determine the equation parameters, a meta‐analysis of seven independent experiments of nutrient requirements was performed, comprising a total of 243 experimental units (animals), which were conducted under tropical conditions, using hair sheep in growing and finishing phases and endowed of the following quantitative data for each animal: body weight (BW ), empty body weight (EBW ), average daily gain (ADG ), empty body gain (EBG ), heat production (HP ), metabolizable energy intake (MEI ), retained energy (RE ), metabolizable protein intake (MPI ) and body protein content. The regression equations generated were as follows: for Net Energy for maintenance, (NE _m): ; for Net Energy for gain, (NE _g): ; for Metabolizable Protein for maintenance,(MP _m): MPI _(g/day) = 24.8470 (±7.3646) + 560.28 (±99.6582) × EBG _(kg/day); for Net Protein for gain, (NP _g): . The NE _m requirement was 0.246 MJ EBW^?0.75 day^?1. The metabolizable energy for maintenance requirement was 0.391 MJ EBW^?0.75 day^?1. Considering an ADG of 100 g, the NE _g requirement ranged from 0.496 to 1.701 MJ/day for animals with BW ranging from 10 to 40 kg respectively. The efficiencies of use of the metabolizable energy for maintenance and gain were 0.63 and 0.36 respectively. The MP _m requirement was 3.097 g EBW^?0.75 day^?1. Considering an ADG of 100 g, the NP _g requirement ranged from 12.4 to 10.5 g/day for animals with BW ranging from 10 to 40 kg respectively. The total metabolizable energy and protein requirements were lower than those reported by the NRC and AFRC systems. Thus, our results support the hypothesis that nutrient requirements of hair sheep raised in tropical regions differ from wool sheep raised in temperate regions. Therefore, the use of the equations designed in this study is recommended.