农业经济管理分类的研究

运用多元统计分析中的分层聚类分析和判别分析方法,借助SPSS统计软件进行统计分析,以西藏自治区的35个农业县为研究对象,根据2007年西藏农业县农林牧渔业产值、粮食产量、工业总产值等主要统计指标为分类变量,对农业县进行分类,根据所得出的结论,客观、合理地提出合理性的建议.     

Loss of intraspecific aggression in the success of a widespread invasive social insect

Despite the innumerable ecological problems and large economic costs associated with biological invasions, the proximate causes of invasion success are often poorly understood. Here, evidence is provided that reduced intraspecific aggression and the concomitant abandonment of territorial behavior unique to introduced populations of the Argentine ant contribute to the elevated population densities directly responsible for its widespread success as an invader. In the laboratory, nonaggressive pairs of colonies experienced lower mortality and greater foraging activity relative to aggressive pairs. These differences translated into higher rates of resource retrieval, greater brood production, and larger worker populations.     

基于Logistic模型探究西藏巨柏播种苗生长规律

运用Logistic模型和二维有序样品聚类法分析了西藏巨柏播种苗生长过程,并建立了苗高和地径、生长时间与苗高之间的拟线性回归模型。分析结果显示：各个回归模型的相关系数都达到了显著水平。为科学培育巨柏优质苗木提供了理论依据。     

Advances in pasture management for animal productivity and health

A wide range of management techniques is available to enhance quantity and quality of forage supply to grazing animals throughout the annual production cycle. Within broad limits, dry matter (DM) production is relatively insensitive to management of defoliation frequency, severity and duration. However defoliation management has effects on feed quality which can be enhanced, in particular, by control of pasture growth in the spring through maintenance of relatively low average pasture masses. Treading damage can have significant immediate and ongoing effects on pasture production and farmers can use a range of management techniques to minimise these.

Fertiliser application practices have a potent influence on pasture production and seasonality of that production. Available soil nitrogen is the primary nutrient deficiency limiting production in New Zealand's characteristically grass-dominant pastures. Nitrogen fertiliser usage has increased markedly in recent years, particularly to grow substantially greater amounts of forage during the cool season, and this trend looks set to continue. However, the use of nitrogen fertiliser has important environmental implications.

Pasture renewal and forage crop use has also increased in recent years. Care needs to be taken in conducting cost-benefit analyses, selecting the options that best meet the needs, and in establishment and subsequent management practices. Ryegrass (perennial and hybrids) and white clover remain the primary choice for permanent pasture renewal, the availability of safe endophytes having largely alleviated effects of endophyte toxicosis. Special-purpose mixtures are used, especially in dry environments. Italian ryegrasses, brassicas and chicory are common choices for forage crops. A range of management techniques can be used to alleviate deleterious effects of some forages, including ryegrass endophyte toxicosis, facial eczema, and toxins associated with Fusarium fungi. Generally these techniques are not totally effective. More research is required to increase our understanding of these disorders, and in order to develop more effective and reliable management practices.     

三维冰雹云模式对巴彦淖尔市一次冰雹天气过程的数值模拟研究

为了深入研究巴彦淖尔市冰雹云形成的宏微观条件,利用三维冰雹云模式对该地区的一次冰雹天气进行了数值模拟,并探讨了三维冰雹云模式的适用性。结果表明:模式能够模拟出冰雹云发生、发展、成熟、消散的过程,最大上升气流以及降雹量的特征,表明此次冰雹云具有连续发展的态势。模式中固态水成物粒子对降水的形成有重要作用,模拟出的最大冰雹直径为4.362mm。分析冰雹云的流场结构、总水成物场的分布与演变发现,较强的辐合上升气流为冰雹云的发展提供了动力条件,有利的总水成物分布为冰雹云提供了水汽条件。针对冰雹粒子的微物理过程,此次巴彦淖尔市冰雹粒子以霰粒子的自动转化(CNgh)增长为主,冰雹碰并雪增长(CLsh)为辅,适量的冰晶及丰富的过冷水的存在,对此次冰雹云的形成和增长极为有利。三维冰雹云模式的应用,能够判断是否有冰雹发生,以及冰雹的起止时间,为巴彦淖尔市冰雹的预报提供了帮助。     

我国民营企业贷款的距离影响因素分析

选取我国2011年沪深两市A股的628家民营上市企业的贷款数据为样本进行实证分析发现：银行贷款量与银行到企业之间距离具有显著的负相关关系,说明银企距离是制约我国民营企业贷款的一个重要影响因素;地区金融发展与企业的银行贷款量之间具有显著的负相关的关系,说明了竞争关系对企业外地银行贷款的抑制作用不是表现在区域的银行网点的竞争,而是地区的金融发展。因此,应重视银企距离,加大地区金融发展。     

我国利用蕃麻皂素合成生产地塞米松的现状及需研究的重点

蕃麻皂素即海柯吉宁 ,是一种具开发潜力合成生产地塞米松药物的原料。在论述国内外利用海柯吉宁研究及生产地塞米松现状的基础上 ,指出了国内合成生产存在的问题 ,针对国内用海柯吉宁合成生产地塞米松收率低的问题 ,提出把优化工艺作为合成生产的研究重点 ,且从 3个方面进行研究 ,可将其收率从现在的 6 0 3%提高到 10 %以上     

Pregnancy diagnosis in dairy goats and cows using progesterone assay kits

Early pregnancy diagnosis in dairy goats and cows was studied using enzyme immunoassays (EIA) to measure progesterone concentrations in whole milk samples collected approximately 3 weeks after mating. Two qualitative on-farm assay kits and 2 quantitative assay kits, all designed for use in the dairy cow, were tested for their accuracy with goats milk samples. Accuracy of diagnosis of goat pregnancy ranged from 83 to 88%, and of non-pregnancy from 80 to 100%. Pregnancy diagnosis with samples of cows milk using 2 quantitative kits gave accuracies of 66 to 68% for pregnancy, and 90 to 91% for non-pregnancy. Possible causes of error in the early diagnosis of pregnancy with milk samples are discussed.