草业琐谈之三十四胡杨泪

自从1950年来到西北,胡杨就是我的老相识了.胡杨的坚韧和壮美令人折服.胡杨(还有牦牛,这里暂且不说)是我心中的图腾,我对它顶礼膜拜.     

草业琐谈之四十一越南琐忆——感人的友情

回忆越南,最想表达的是中越两国人民的友情.但偏偏最后来写,因为内容太丰富,再三咀嚼回味,也难以理出个头绪来.     

山西玉米产业现状与发展思考

目的研究能快速准确测定玉米种子活力的技术方法。方法采用3个年份生产的杂交玉米种子,玉米种胚经四唑染色后,利用数码显微镜 (Smart Zoom 5) 拍照和获取四唑染色图像,测定种胚中胚根、胚轴、胚芽和子叶(盾片)结构的染色面积和染色深浅,并与田间出苗率做相关性分析。结果玉米种胚各结构全部染色且颜色深时,种子活力水平与田间出苗率具有显著相关性,其相关系数为1.000;若种胚全部未染色、全部染色浅和只有部分结构染色的种子则与田间出苗率呈显著负相关关系,其相关系数分别为−0.905、−0.921和−1.000。结论玉米种子经四唑染色后,只有种胚结构全部染色且颜色深的种子,在田间才能够出苗,可判定为有活力的种子;而种胚部分结构染色或者全部染色但颜色浅的种子,在田间不能出苗,即为无活力的种子。这一结论可为快速测定玉米种子活力提供新的技术方法和指标,为玉米种子质量检验提供了一种准确、实用、方便和廉价的测定方法,可供种子检验机构和种业公司采用。     

牡蛎糖原的研究 (II)——牡蛎糖原的分子结构

该研究以新鲜近江牡蛎 (Crassostrea ariakensis) 软体组织为实验材料,通过比较分析不同蒽酮硫酸比例、不同反应时间的吸光值确定最优反应条件,并对方法的最低检出限、重复性、稳定性和精确性进行评价,最终建立了牡蛎糖原含量的微量检测体系。建立的微量反应体系体积为300 μL,主要包括0.2%蒽酮硫酸溶液200 μL,样品待测液100 μL;沸水浴反应时间为10 min。该方法的葡萄糖最低检出限为0.001 5 mg·mL⁻¹,标准曲线变异系数小于4%,证实该方法具有较高的检测灵敏度;显色反应完成后,室温条件下120 min内其吸光值基本不变,稳定性较高;测定牡蛎外套膜、鳃、唇瓣、性腺、肝胰腺、闭壳肌的加标回收率介于95.3%~105.8%,说明该法具有较高的准确性。因此,该研究建立的微量反应体系测定牡蛎糖原的方法具有试剂用量小、操作简单、单样品成本低等优势,同时重复性、稳定性、精确性均较高,适用于大批样品批量测定。该研究为快速、高效完成牡蛎样品糖原的检测提供了有效的技术方法。     

基于反馈回归法的用电量预测模型研究

多元线性回归法是用电量预测中常用的一种方法,带反馈的多元线性回归法是一种改进的回归方法,具有更高的精度.本文在此基础上进行了多次反馈,即利用带多次反馈的多元线性回归法,结合SPSS软件进行统计分析,并以陕西省用电量为例探究分析多次反馈的多元线性回归法在用电量预测中的应用,从而得到更精准的用电量预测模型.最后以四川省的用电量数据对模型进行了验证,体现出了该模型的优越之处.     

Polymorphism of Kappa-casein gene and its associations with milk performance traits in red steppe

为研究草原红牛κ-酪蛋白基因的多态性及与泌乳性状相关性,采用PCR-RFLP方法检测κ-酪蛋白基因外显子5的遗传多态性.结果检测到TT、TC和CC三种基因型,统计分析表明,此多态位点与草原红牛乳蛋白和乳糖呈显著相关,乳蛋白:CC基因型极显著高于CT基因型和TT基因型(P＜0.01),而CT基因型也极显著高于TT基因型(P＜0.01).乳糖:TT基因型和TC基因型极显著高于CC基因型(P＜0.01),而TT和TC基因型之间差异不显著(P＞0.01).其他泌乳性状的基因型间差异不显著(P＞0.01).结果表明,κ-CN基因对草原红牛乳蛋白和乳糖具有较大的遗传效应,可初步推断κ-CN是控制这一性状的众多基因之一,是影响草原红牛乳蛋白和乳糖的一个主效基因或与主效基因相连锁,可作为选育草原红牛高乳蛋白及低乳糖奶牛的分子标记,用于标记辅助选择意义重大.     

气调袋保鲜青菜头(茎瘤芥)的研究

检测青菜头贮藏过程中MA袋内气体指标变化和贮藏后的品质指标,并进一步探讨贮藏效果最佳MA袋的袋装量和硅窗面积对青菜头贮藏保鲜效果的影响。结果表明,PE硅窗袋、PVC硅窗袋和SCA袋内气体指标在一定时间后达到相对平衡,定期换气袋内气体呈不稳定周期性变化。PVC硅窗袋贮藏效果较好,PE硅窗袋和SCA袋次之,定期换气袋较差。当袋装量15 kg,硅窗面积为110 mm×75 mm时,PVC硅窗袋贮藏保鲜效果达到最好。     

Energy requirements of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation

This experiment was conducted to investigate the energy requirement of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation. Fifteen ewes after parturition were randomly assigned to three treatments: ad libitum(100%) feed intake and 80 or 60% ad libitum intake, and another nine non-pregnant ewes were assigned to a blank control group. Digestibility trials were performed in the non-pregnant ewes and in the lactating ewes on the 20 th, 50 th, and 80 th d of lactation. In parallel with the digestibility trial, a respirometry experiment was conducted to determine the methane and carbon dioxide production with an open-circuit respirometry system that was equipped with respiratory chambers. The net energy(NE) and metabolizable energy(ME) requirements for maintenance and growth were calculated using the carbon and nitrogen balance method. The results revealed that the carbon(C) and nitrogen(N) excretions and energy losses at faeces and urine, as well as the output of methane and CO2, increased significantly with decreasing feed intake(P0.01). The apparent digestibilities of C in th e stages of non-pregnancy and early, middle and late lactation were 55.8–58.3%, 62.5–73.8%, 64.8–71.3%, and 61.7–65.0%, respectively, and the apparent digestibilities of N were 45.2–51.3%, 73.7–82.7%, 72.8–80.5%, and 73.6–76.5%, respectively. The corresponding energy apparent digestibilities were 52.0–56.3%, 60.7–76.6%, 61.0–68.8%, and 61.4–67.7%, respectively. The ME/DE(digestible energy) values were 79.5–85.9%, 79.4–83.5%, 81.0%–85.3% and 78.6–82.9%, respectively. The maintenance requirements of NE, ME, and the efficiencies of ME utilisation for maintenance during the stages of non-pregnancy and early, middle and late lactation were 215.5, 253.1, 247.7, and 244.7 k J kg~(–1) BW0.75 d, and 372.4, 327.1, 320.9, and 362.0 k J kg~(–1) BW0.75 d, and 0.58, 0.77, 0.77, and 0.68, respectively. The ME requirement for the growth of non-pregnant ewes was 31.3 MJ kg~(–1) BW gain.     

PFI-Private Finance in Public Works

PFI is one of the novel approaches for the private finance in public works. The initiative aims on encouraging the private sector to undertake infrastructure projects and the provision of services on a project basis, rather than by the traditional means of procurement. PFI has been widely applied in a large number of fields in public works of government. PFI has become one of the government's main instruments for delivering higher quality and more effective public services. Two of the principal tenets of PFI is: the first is to secure value for money for the public sectors and the second to transfer the ongoing risk in the continued delivery of a service away from the public sector to the private sector.