首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7篇
  完全免费   1篇
  轻工业   8篇
  2021年   2篇
  2015年   1篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
排序方式: 共有8条查询结果,搜索用时 133 毫秒
1
1.
原料乳体细胞数与纤溶酶活性的相关性研究   总被引:2,自引:0,他引:2  
随机检测了102个原料乳样品的体细胞数(SCC)与纤溶酶(PL)活性.结果显示,SCC与PL活性之间存在一定的正相关.以总体为样本,PL活性与SCC线性相关系数为0.7367;SCC>3×105mL-1样本的相关系数达到0.7928,SCC>5×105mL-1样本的相关系数达到0.8616.SCC在<3×105 mL-1时SCC与PL无相关性.人工调配的含不同SCC的11个原料乳样,采用荧光染色法进行SCC计数,其理论折算数和实际数配对两处理f检验,结果t=1.2787,P=0.2299,差异不显著.线性回归分析得:Y=1.0055X-3.4473(R2=0.9996).11个人工调配SCC原料乳样品的PL活性随SCC数的增加而明显增加(R2=0.9619).通过超声波处理模拟SCC自溶状态,原料乳中体细胞经超声波处理后.PL活性明显增加.  相似文献
2.
高转速楔块式超越离合器研究   总被引:2,自引:1,他引:1  
孔炜  朱春梅 《轻工机械》2009,27(6):79-81
楔块式超越离合器是机电传动系统的重要功能部件。传统保持架结构的超越离合器在高转速工况下,存在楔块容易翻转、磨损大和制造工艺性差等缺点。在分析传统保持架结构的基础上。对新型高转速保持架结构楔块超越离合器主要零件结构、工作原理和特点进行了研究,并对新型超越离合器的工作性能进行了测试。  相似文献
3.
从不同角度包括儿童肥胖趋势、基因突变与膳食模式相关性、儿童肥胖食物成瘾理论、儿童期细胞增殖型肥胖、营养不良性维生素缺乏导致脂肪生长因子活性增加阐述了儿童膳食模式或习惯与其肥胖关系的多层次观点。研究表明,儿童单纯性肥胖因素重要因素之一为膳食因素,主要表现为高糖高脂低纤维的模式;儿童与成人干预策略完全不同,提出执业护士作为流行病学调查、基因评估护理、一级预防的主力军等观点。  相似文献
4.
以调查问卷的形式对合肥乳制品消费情况进行了调查。问卷共发放了1 000份,回收有效问卷869份,问卷有效率86.9%。调查群体集中反映了合肥市当地青壮年市民乳制品消费情况。通过调查得知,一线城市乳制品消费人群已形成稳定乳制品消费习惯,而且消费水平高于全国城镇居民乳制品消费平均水平;酸奶、常温奶和需要冷链储藏鲜奶成为大城市消费的主流,且安全、营养、品牌成为选择乳制品的重要考虑;消费者对当前乳制品质量安全比较放心,对外国品牌的乳制品较为认可;城市人群获取乳制品相关信息的重要渠道为电视节目。  相似文献
5.
以鲐鱼为研究对象,进行恒温下细菌总数的计数并建立基于Baranyi模型的微生物生长动力学模型。对Baranyi模型进行改进,构建波动温度下的微生物生长动力学模型,并运用模拟实验对模型进行验证,验证结果是偏差因子为1.23,准确因子为1.12,表明所构建的微生物生长动力学模型能够很好的拟合波动温度下鲐鱼中微生物的变化情况。  相似文献
6.
在2010年3月26日由卫生部颁布的首批食品安全国家标准——66个乳品标准里,其中标准号为GB25191—2010的国家标准,以一个从未使用过的新概念"调制乳"命名。本文从相关的国际标准、加工工艺、添加剂使用等不同角度,结合我国乳品标准发展过程中存在的矛盾和问题,阐述引入"调制乳"新概念的合理性和重要性。  相似文献
7.
Heat stress is a major cause of welfare issues and economic losses to the worldwide dairy cattle industry. Genetic selection for heat tolerance has a great potential to positively affect the dairy industry, as the gains are permanent and cumulative over generations. Rectal temperature (RT) is hypothesized to be a good indicator trait of heat tolerance. Therefore, this study investigated the genetic architecture of RT by estimating genetic parameters, performing genome-wide association studies, and biologically validating potential candidate genes identified to be related to RT in Holstein cattle. A total of 33,013 RT records from 7,598 cows were used in this study. In addition, 1,114 cows were genotyped using the Illumina 150K Bovine BeadChip (Illumina, San Diego, CA). Rectal temperature measurements taken in the morning (AMRT) and in the afternoon (PMRT) are moderately heritable traits, with estimates of 0.09 ± 0.02 and 0.04 ± 0.01, respectively. These 2 traits are also highly genetically correlated (r = 0.90 ± 0.08). A total of 10 SNPs (located on BTA3, BTA4, BTA8, BTA13, BTA14, and BTA29) were found to be significantly associated with AMRT and PMRT. Subsequently, gene expression analyses were performed to validate the key functional genes identified (SPAG17, FAM107B, TSNARE1, RALYL, and PHRF1). This was done through in vitro exposure of peripheral blood mononuclear cells (PBMC) to different temperatures (37°C, 39°C, and 42°C). The relative mRNA expression of 2 genes, FAM107B and PHRF1, significantly changed between the control and heat stressed PBMC. In summary, RT is heritable, and enough genetic variability exists to enable genetic improvement of heat tolerance in Holstein cattle. Important genomic regions were identified and biologically validated; FAM107B and PHRF1 are the main candidate genes identified to influence heat stress response in dairy cattle.  相似文献
8.
Genetic selection for improved climatic resilience is paramount to increase the long-term sustainability of high-producing dairy cattle, especially in face of climate change. Various physiological indicators, such as rectal temperature (RT), respiration rate score (RR), and drooling score (DS), can be used to genetically identify animals with more effective coping mechanisms in response to heat stress events. In this study, we investigated genetic parameters for RT, RR (score from 1–3), and DS (score from 1–3). Furthermore, we assessed the genetic relationship among these indicators and other economically important traits for the dairy cattle industry. After data editing, 59,265 (RT), 30,290 (RR), and 30,421 (DS) records from 13,592 lactating Holstein cows were used for the analyses. Variance components were estimated based on a multiple-trait repeatability animal model. The heritability ± standard error estimate for RT, RR, and DS was 0.06 ± 0.01, 0.04 ± 0.01, and 0.02 ± 0.01, respectively, whereas their repeatability was 0.19, 0.14, and 0.14, respectively. Moderate genetic correlations of RR with RT and DS (0.26 ± 0.11 and 0.25 ± 0.16) and nonsignificant correlation between RT and DS (−0.11 ± 0.14) were observed. Furthermore, the approximate genetic correlations between RT, RR, and DS with 12 production, 29 conformation, 5 fertility and reproduction, 5 health, and 9 longevity-indicator traits were assessed. In general, the approximate genetic correlations calculated were low to moderate. In summary, 3 physiological indicators of heat stress response were measured in a large number of animals and shown to be lowly heritable. There is a value in developing a selection index including all the 3 indicators to improve heat tolerance in dairy cattle. All the unfavorable genetic relationships observed between heat tolerance and other economically important traits can be accounted for in a selection index to enable improved climatic resilience while also maintaining or increasing productivity in Holstein cattle.  相似文献
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号