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61.
在中国革命和社会主义建设中萌芽、凝练的农垦精神,成为各项事业发展,尤其是农业发展的核心价值观。农垦精神与社会主义核心价值观有着密切的内在关联性,二者具有相同的爱国属性、文化基因和理想依托。以农垦精神为核心,开展思想教育、实践教育、文化教育,是高校践行社会主义核心价值观的重要维度。  相似文献   
62.
红壤旱地芝麻防早衰叶面调控剂筛选研究   总被引:2,自引:0,他引:2  
研究结果表明,速效肥料、生长调节剂及抗病药剂对保持芝麻生长中后期的正常生长都能起到积极作用。"磷酸二氢钾+硝酸铵+腐植酸+赤霉素"配制能有效防控红壤旱地芝麻早衰,在此配方基础上,添加代森锰锌能对防控芝麻叶部及茎部病害起到一定的作用,从而增强了红壤旱地上芝麻的抗早衰能力。  相似文献   
63.
李娟 《农业网络信息》2012,(11):151-152
讨论了独立院校针对非计算机专业学生Visual Basic程序设计课程的重要性,并探讨了实践教学方法.  相似文献   
64.
萎凋是红茶、乌龙茶等发酵茶加工的重要工序之一,对茶叶感官品质影响明显。萎凋过程中,随着水分的不断散失,鲜叶的呼吸作用持续进行,内质成分发生剧烈变化,促使萎凋叶物理特性发生改变,为后续工序和品质形成提供特定的物质和叶形基础。文章对萎凋过程中鲜叶的物理特性和生化成分变化规律,以及目前萎凋工艺关键参数的调控技术等进行了系统综述。可精准调控环境温度、湿度、光照、通气状况等参数的设施萎凋技术是今后萎凋技术发展的重要方向。  相似文献   
65.
“概论”课理论性、现实性很强,在当前我国社会转型和改革攻坚深刻影响人们思想的形势下,如何讲好“概论”课对教师的教学理念、教学方法、技能和知识结构都提出了很高的要求.笔者在认真分析学生对思想政治理论课需求的基础上进行了一系列教学方法改革和实践:坚持理论联系实际,讲好讲活理论;采取互动教学方法,让学生更多的参与教学;灵活运用多媒体技术;通过实践教学促进课堂教学;举办多种专题讲座,拓展学生思维和视野.  相似文献   
66.
Genomic selection (GS) is now practiced successfully across many species. However, many questions remain, such as long-term effects, estimations of genomic parameters, robustness of genome-wide association study (GWAS) with small and large datasets, and stability of genomic predictions. This study summarizes presentations from the authors at the 2020 American Society of Animal Science (ASAS) symposium. The focus of many studies until now is on linkage disequilibrium between two loci. Ignoring higher-level equilibrium may lead to phantom dominance and epistasis. The Bulmer effect leads to a reduction of the additive variance; however, the selection for increased recombination rate can release anew genetic variance. With genomic information, estimates of genetic parameters may be biased by genomic preselection, but costs of estimation can increase drastically due to the dense form of the genomic information. To make the computation of estimates feasible, genotypes could be retained only for the most important animals, and methods of estimation should use algorithms that can recognize dense blocks in sparse matrices. GWASs using small genomic datasets frequently find many marker-trait associations, whereas studies using much bigger datasets find only a few. Most of the current tools use very simple models for GWAS, possibly causing artifacts. These models are adequate for large datasets where pseudo-phenotypes such as deregressed proofs indirectly account for important effects for traits of interest. Artifacts arising in GWAS with small datasets can be minimized by using data from all animals (whether genotyped or not), realistic models, and methods that account for population structure. Recent developments permit the computation of P-values from genomic best linear unbiased prediction (GBLUP), where models can be arbitrarily complex but restricted to genotyped animals only, and single-step GBLUP that also uses phenotypes from ungenotyped animals. Stability was an important part of nongenomic evaluations, where genetic predictions were stable in the absence of new data even with low prediction accuracies. Unfortunately, genomic evaluations for such animals change because all animals with genotypes are connected. A top-ranked animal can easily drop in the next evaluation, causing a crisis of confidence in genomic evaluations. While correlations between consecutive genomic evaluations are high, outliers can have differences as high as 1 SD. A solution to fluctuating genomic evaluations is to base selection decisions on groups of animals. Although many issues in GS have been solved, many new issues that require additional research continue to surface.  相似文献   
67.
Cefquinome is a fourth‐generation cephalosporin that is used empirically in goats. Different physiologic factors like pregnancy or lactation could determine the pharmacokinetic behavior of drugs in the organism. The objectives of this study are to (a) compare the pharmacokinetics of cefquinome after intravenous and intramuscular administration in adult nonpregnant (n = 6), pregnant (n = 6), and lactating goats (n = 6), at a dose of 2 mg/kg, with rich sampling by nonlinear mixed‐effects modeling, (b) conduct a pharmacokinetic/pharmacodynamic analysis to evaluate the efficacy of the recommended posology in goats with different physiological states, and (c) determine the optimal posology that achieve a PTA value ≥ 90%, taking into account a T > MIC ≥ 60% of a MIC value ≤ 0.25 µg/ml, in the different subpopulations of goats for both routes. Gestation significantly increased Ka and V1, while reduced F0, Cl, and Q. On the other hand, lactation significantly increased V1 and reduced Tk0. Cefquinome concentrations achieved in placental cotyledon, amniotic fluid, and fetal serum indicate a minimal penetration across the placental barrier. Moreover, milk penetration of cefquinome was minimal. The total body clearance of cefquinome for goats was 0.29 L kg?1 hr?1, that is apparently higher than the reported for cows (0.13 L kg?1 hr?1) and pigs (0.16 L kg?1 hr?1). So, the optimal dose regimen for cefquinome after intravenous and intramuscular administration required higher dose and frequency of administration compared with recommendations for cows or pigs. Therefore, 2 mg kg?1 8 hr?1 and 5 mg kg?1 12 hr?1 could be used for IV and IM routes, respectively, for the treatment of respiratory infections caused by P. multocida and M. haemolytica, but only 5 mg kg?1 12 hr?1 by both routes should be recommended for Escherichia coli infections.  相似文献   
68.
试验旨在探究高浓度葡萄糖对猪卵母细胞体外成熟及早期胚胎发育能力的影响。取体外分离处于生发泡期的猪卵丘卵母细胞复合体(COCs),分为3个处理组。分别用含葡萄糖浓度为5.6 mmol/L(C组)、10 mmol/L(G-1组)、15 mmol/L(G-2组)的培养液,进行体外成熟(IVM)处理,42 h后观察,并统计卵丘细胞扩散情况和第一极体排出率;对体外成熟42 h后的卵母细胞孤雌激活,统计2-细胞、4-细胞和第7天囊胚发育。结果发现,G-1组和G-2组卵丘细胞扩散度显著低于C组(P<0.05);G-1组和G-2组的MII期卵母细胞死亡率和存活率与C组相比无显著差异(P>0.05),但G-1组极体率显著降低(P<0.05),G-2组极体率极显著低于C组(P<0.01)。孤雌激活后,与C组相比,G-1组和G-2组的2-细胞分裂率显著降低(P<0.05),4-细胞分裂率以及囊胚发育率均极显著降低(P<0.01),但G-1、G-2组囊胚细胞数量与C组相比无显著性差异(P>0.05)。进一步线粒体染色发现,G-1组和G-2组的线粒体与C组相比分布不均。与C组相比,荧光结果显示G-1组和G-2组不仅活性氧(ROS)水平极显著升高(P<0.01),而且G-1组与G-2组谷胱甘肽(GSH)含量显著降低(P<0.05),虽然G-1组丙二醛(MDA)无显著性差异(P>0.05),但G-2组丙二醛(MDA)含量显著升高(P<0.05)。研究结果表明,葡萄糖浓度高会影响猪卵母细胞线粒体分布,氧化应激水平升高,成熟效率降低,损害早期胚胎的发育潜能。  相似文献   
69.
测定黄连与黄连须、黄连茎叶主要生物碱含量并建立高效液相(HPLC)指纹图谱,分析其抗氧化活性的谱效关系。采用HPLC分析比较黄连及黄连须、黄连茎叶中小檗碱、表小檗碱、药根碱、黄连碱、巴马汀含量差异并建立指纹图谱,通过羟自由基(·OH)、1,1-二苯基-2-三硝基苯肼(DPPH)自由基、2,2-联氮基双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)自由基体外清除试验与总还原力试验评价其体外抗氧化活性差异,应用Pearson相关系数法分析HPLC指纹图谱与抗氧化活性的谱效关系。结果发现小檗碱、巴马汀含量为黄连>黄连茎叶>黄连须;药根碱、黄连碱和表小檗碱含量为黄连>黄连须>黄连茎叶;总还原力为黄连>黄连茎叶>黄连须,·OH、DPPH、ABTS·+自由基清除力为黄连茎叶>黄连>黄连须;总还原力与各峰均有较强相关性,·OH、DPPH、ABTS·+自由基清除力与4号峰相关性较强。说明黄连茎叶体外抗氧化活性较强,黄连须与黄连茎叶均有一定药用开发价值。  相似文献   
70.
Aquaculture production relies on controlled management of gametogenesis, especially in species where assisted reproduction is needed for obtaining gametes in captivity. The present study used human chorionic gonadotropin (hCG) treatments to induce and sustain spermatogenesis in European eel (Anguilla anguilla). The aim was to evaluate effects of strip-spawning timing (12 vs. 24 hr) after weekly administration of hCG and the necessity of a primer dose (in addition to weekly hormonal treatment) prior to strip spawning (primer vs. no-primer) on sperm quality parameters. Sperm parameters included milt production (weight), density and sperm kinematics at Week 9, 11 and 13 after onset of treatment. Spermiation commenced in 11.5% of males in Week 5 and by Week 9, and all males produced milt. Male weight, milt production, sperm density and spermatocrit did not differ among hormonal treatments during the experimental period. Overall, male weight decreased from 106.3 to 93.0 g, milt weight increased from 3.5 to 5.4 g, sperm density counts decreased from 11.7 × 109 to 10.5 × 109 cells/ml, and spermatocrit decreased from 46.5% to 40.5%. Furthermore, spermatocrit was positively related to haemocytometer counts (R2 = .86, p < .001), providing a reliable indicator of sperm density. Differences in sperm kinematics were observed depending on strip-spawning timing after hormonal injection (12 vs. 24 hr) but with no consistent pattern. These sperm quality parameters also did not consistently differ between the no-primer and primer treatments. Considering that each male may be stripped 4–5 times over the 2–3 months spawning season, omitting the primer would reduce animal handling, material costs and labour intensity, while sustaining high-quality sperm production.  相似文献   
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