农牧业实行家庭承包经营的比较分析

本文通过对农牧业（种植业和养殖业）中实行家庭承包经营责任制的比较分析,旨在阐明在畜牧业中实行草畜分包经营的合理性。联系实际提出了几点措施。     

大尾寒羊产羔数对胎次的回归分析

该研究利用SPSS软件分析了大尾寒羊产羔数对胎次的回归,大尾寒羊产羔数对胎次的二次方回归和三次方回归的拟合度(R2)分别为0.9246和0.9269,可见两种模型下的回归方程的拟合度都比较高。产羔数对胎次的二次方回归方程中的所有回归参数均达到极显著水平(P<0.01),说明大尾寒羊产羔数对胎次用二次方回归方程具有一定的应用价值。     

义素分析在汉语词汇教学中的运用

词义是现代汉语词汇教学的一个重要组成部分,用义素分析法对词义进行剖析,能够清楚地显示词义的内部结构。在释义、考察词语组合以及同义词的辨析中引入义素分析法,可以帮助学生克服对词义囫囵吞枣的现象,从而准确地把握和运用词义。     

猪UCP3基因的分离与多态分析

解偶联蛋白3是一种线粒体内膜上的转运蛋白,可以使氧化过程与ADP磷酸化过程解偶联。本研究分离了猪UCP3基因的外显子2~3和外显子6。经过序列分析,发现猪UCP3基因共有3处框移突变和18个SNP位点。在猪UCP3片段中分别包含一个SmaⅠ和SduⅠ酶切位点。UCP3片段SmaⅠ位点在大白×梅山F2家系中经PCR-RFLP分析,表现为AA、AB和BB 3种基因型,A基因频率为0.57,B基因频率为0.43。因此,可以将UCP3基因作为猪分子遗传育种的候选基因。     

环模制粒机转子轴承脂润滑的分析与计算

对于环模制粒机主轴滚动轴承,选择合适的润滑脂,分析润滑机理,进行最小油膜厚度计算,考虑轴承润滑寿命影响因素和修正系数,进行轴承润滑寿命计算,讨论影响因素,提出维护保养措施,为合理和正确地使用轴承润滑提供依据.     

A comparison between multivariate Slash, Student's t and probit threshold models for analysis of clinical mastitis in first lactation cows

Robust threshold models with multivariate Student's t or multivariate Slash link functions were employed to infer genetic parameters of clinical mastitis at different stages of lactation, with each cow defining a cluster of records. The robust fits were compared with that from a multivariate probit model via a pseudo‐Bayes factor and an analysis of residuals. Clinical mastitis records on 36 178 first‐lactation Norwegian Red cows from 5286 herds, daughters of 245 sires, were analysed. The opportunity for infection interval, going from 30 days pre‐calving to 300 days postpartum, was divided into four periods: (i) ?30 to 0 days pre‐calving; (ii) 1–30 days; (iii) 31–120 days; and (iv) 121–300 days of lactation. Within each period, absence or presence of clinical mastitis was scored as 0 or 1 respectively. Markov chain Monte Carlo methods were used to draw samples from posterior distributions of interest. Pseudo‐Bayes factors strongly favoured the multivariate Slash and Student's t models over the probit model. The posterior mean of the degrees of freedom parameter for the Slash model was 2.2, indicating heavy tails of the liability distribution. The posterior mean of the degrees of freedom for the Student's t model was 8.5, also pointing away from a normal liability for clinical mastitis. A residual was the observed phenotype (0 or 1) minus the posterior mean of the probability of mastitis. The Slash and Student's t models tended to have smaller residuals than the probit model in cows that contracted mastitis. Heritability of liability to clinical mastitis was 0.13–0.14 before calving, and ranged from 0.05 to 0.08 after calving in the robust models. Genetic correlations were between 0.50 and 0.73, suggesting that clinical mastitis resistance is not the same trait across periods, corroborating earlier findings with probit models.     

副猪嗜血杆菌S-核糖基高半胱氨酸酶基因序列分析与推导蛋白三维结构的分子模拟

利用PCR方法获得副猪嗜血杆菌S-核糖基高半胱氨酸酶(luxS)基因全长DNA,将PCR纯化产物与pMD18-T载体连接并转化E.coil DH5α菌株,重组阳性质粒测序并采用生物信息学软件对所推导的氨基酸序列进行三维结构分析。结果表明,该基因全长510bp,并与GenBank中登录的其他5株菌株luxS基因完整参考序列进行比较,同源性均在70%以上。用ExPAsy软件包预测了推导蛋白的特性,运用Swiss-PDB viewer软件的SWISS-Model处理器,并利用同源建模的思想建立HPS-luxS的三维结构。拉马钱德兰图证明,构建的luxS蛋白的空间结构是合理的。     

《草业学报》引文统计与分析

对《草业学报》从创刊到１９９６年发表论文的引文数量、引文语种、引文类型、自引率、衰减系数等进行了统计和分析，结果表明，《草业学报》的引文率为８．４６条／篇，引文语种：中文占５８．２０％，英文占４０．９１％，此两项测度值均较高；自引率为２．７６％，衰减系数为３３．９６％，均较低；引文类型主要为期刊，占６７．８６％，其次为图书占２８．４９％。上述统计与分析，可供作者、读者和编者全面了解、评价和改进《草业学报》质量作为参考。     

三峡水库重庆库区移土培肥的效益分析——以云阳县为例

应用前后对比分析法,对三峡水库重庆库区云阳县移土培肥一期与二期工程进行效益分析;得出移土培肥工程将给三峡库区带来巨大的生态效益、经济效益和社会效益的结论;说明该工程不仅能带动库区经济发展,并对其社会及生态环境产生深远影响。     

墨西哥柏育苗试验结果分析

切根及喷云大- 120 对墨西哥柏苗木生长的效果的试验结果表明: 切根和喷云大- 120 处理对墨西哥柏苗木生长的促进作用不大。在苗高、地径、冠幅等10 个性状中, 仅切根对茎叶鲜重呈明显负作用, 切根、喷云大- 120 及交互作用对根鲜重亦呈明显的负作用。在墨西哥柏育苗中不宜采用切根和喷云大-120 处理。