基于仿真理论确定缓冲特性曲线方法的研究

本论文探索了一条确定缓冲特性方法的新途径，通过测定缓冲材料的静态特性与一次动态；中击数据为基础，建立数学模型，利用最小二乘法进行误差分析，并使用Madab/Simulink软件仿真出缓冲特性曲线。这种方法得出的缓冲特性曲线准确性高、试验周期短，待理论成熟必将成为今后缓冲材料特性测试的主要方法。     

5种光响应模型对小叶杨的适用性分析

采用Li-6400光合仪测定CO2400μmol·mol-1条件下小叶杨的光响应数据。分别采用直角双曲线修正模型、二次多项式模型、直角双曲线模型、非直角双曲线模型及指数模型对光响应曲线进行拟合,探讨5种模型对小叶杨的适用性。结果表明:直角双曲线、非直角双曲线及指数模型不能处理光抑制部分的光响应数据,且得到的最大净光合速率大于实测值,光饱和点远小于实测值;二次多项式虽能处理光抑制部分的光响应数据,但得到的光合参数有悖常识;直角双曲线修正模型不仅能处理光抑制部分的光响应数据,且拟合得到的各项光合参数均与实际相符,是拟合小叶杨光响应曲线的最适宜模型。     

Dairy sheep production research at the University of Wisconsin-Madison,USA-a review

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or     

用数值方法解决弹道曲线的有关问题

利用龙格—库塔方法解弹道曲线方程组，其精度不够，也不能较完整地给出道弹曲线的解析式。本文直接从解内察方程出发，运用祥条函数磨光法，解决了这些问题，也解决了弹道曲线的计算与选择问题。     

小尾寒羊泌乳期母羊能量需要量及代谢规律研究

选择有代表性的小尾寒羊泌乳母羊6只，分成哺育单羔和双羔两组，每组3只，分泌乳前期（1～30天），泌乳中期（31～60天）和泌乳后期（61～90天）3个阶段进行饲养试验、消化代谢试验、呼吸测热试验及屠宰试验等研究。两组试羊均按NRC（1978）推荐的绵羊泌乳期哺育双羔母羊能量需要量供给代谢能和其它养分。结果表明，在本研究条件下，小尾寒羊泌乳母羊（包括哺育单、双羔者）在整个泌乳期内的平均日干物质（DM）、有机物质（OM）、代谢能（ME）和泌乳量分别为1689g，1571g，19．893MJ和653g。DM、OM和总能（GE）表观消化率分别为70.71％，72．58％和70．34％，代谢率（MEI／DEI）为84．89％。甲烷能占GEI的9．18％。每日畜体产热量（HP）为625．5KJ／kgW0.75。研究还表明：小尾寒羊泌乳母羊的每日维持代谢能和净能需要量分别为582．6和460KJ／kgW0.75，每户1kg原乳需要10802KJ的代谢能。维持效率为0．790泌乳效率为0．479，HI占GEI的18．10％。分析结果证明，试羊的泌乳量、采食量、畜体产热量和能量转化效率在单、双羔之间均无显著差异（P＞0．05）。小尾寒羊泌乳母羊的代谢能总需要量（MER）可用下式估计：羊羔：MER＝576．9W0.75＋10810M；双羔：MER＝588．2W0.75＋10794M；平均：MER＝582．6W0.75＋1     

支链氨基酸对泌乳母猪的营养研究进展

支链氨基酸 (BCAA)是畜禽的必需氨基酸 ,有着重要的营养生理作用 ,对泌乳母猪尤其显著。本文着重阐述BCAA　　对泌乳母猪生产性能方面的影响 ,泌乳母猪对BCAA的需要量及缬氨酸需要量研究模式。     

Statistical analysis of growth curves in plant breeding

Summary In the first part of this paper some experimental conditions necessary for a valid statistical analysis of differences in growth curves are discussed.Next the multivariate character of growth curves is considered. Data on the growth curves of three genotypes of an experiment with tomatoes of the IVT are used for illustrating the computational procedure and some aspects of interpretation.The growth curves of log dry leaf weight for each plot could be described by a quadratic function of time and were characterised by three components: mean level m, slope 1 (linear component) and curvature q (quadratic component).Univariate analyses of variance (ANOVA) showed significant differences between cultivars for each growth component: however, this is only part of the information as the correlation between the components is not involved. From a multivariate analysis of variance (MANOVA) it appeared that in this experiment the differences in growth between the cultivars were best expressed by using mean level m only.An estimate of the final (reduced) statistical model underlying the tomato example is derived.It is advised to split up growth into different phases of development each with its own analysis. At least four harvest dates for every phase seem desirable.     

Intestinal absorption of forsythoside A in different compositions of Shuang-Huang-Lian

Shuang-Huang-Lian (SHL), a traditional Chinese formula containing Lonicerae japonicae flos (LJF), Scutellariae radix (SR) and Forsythiae fructus (FF), is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. Forsythoside A is one of the main active ingredients in Forsythiae fructus, a key herb in SHL. In the present study, effects of different compositions in SHL on the intestinal absorption of forsythoside A were investigated. The observations from in situ intestinal circulation model showed that A/%(h^− 1) of forsythoside A in FF + LSF, FF + SR and SHL were all reduced greatly compared with that in FF. However, in pharmacokinetics study, C_max and AUC_0 → 1440 of forsythoside A all increased and T_1/2 prolonged in SHL, FF + LJF and FF + SR compared with FF. The results indicated that the different compositions of SHL decreased absorption but increased bioavailability of forsythoside A, which may be related to its metabolism inhibited in intestine or liver.     

Composition and diversity of five major forest types in moist temperate climate of the western Himalayas

The present study was undertaken in five major forest types (dominated by Quercus semecarpifolia, Quercus floribunda, Acer acuminatum, Abies pindrow and Aesculus indica, respectively) between 2400 and 2850 m a.s.l. in a moist temperate forest of the Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim was to assess the variation in composition and diversity in different vegetation layers, i.e., herb, shrub and tree, among these five forest types. Diversity indices, such as the Shannon-Wiener diversity index, density, total basal cover, Simpson’s concentration of dominance index, Simpson’s diversity index, Pielou’s equitability, species richness, species heterogeneity and β-diversity, were calculated to understand community structures. Dominance-diversity curves were drawn to ascertain resource apportionment among various species in different forest types.     

影响西藏杂交改良牛泌乳性能因素的分析与建议

西藏牛常年生活在青藏高原,是产乳为主,乳肉兼用的地方品种,对高寒低氧的特殊环境有着极强的适应能力,其泌乳性能满足部分藏民对乳制品的需要。随着藏民生活水平的提高和入藏旅游人数的增加,藏区对乳制品的需求也越来越大,但西藏牛本身泌乳性能低的缺点制约了西藏奶业的快速发展。通过杂交改良提高西藏牛泌乳性能的方法在藏区从开始至今已有60余年,但其后代对高原适应能力会随着杂交代数的推进减弱,从而对其泌乳量造成影响,所以杂交改良的方法还需进一步的深入研究。本文以目前影响西藏牛泌乳性能的因素展开讨论和分析,剖析其存在的问题,以期为西藏牛杂交改良和高原引种提供一定的思路。