Experiment research on aseismatic capability of diagonally crossing reinforced coupling beams with the small ratio of span to depth fire safety design for ancient buildings

Low frequency cyclic loading experiments are carried out with six diagonally crossing reinforced coupling beams. The ratio of the span to depth is 1.0,1.5,2.0 and 2.5. The paper analyzes the behavior of crack development, failure mode, ductility, stiffness degeneration, hysteretic and energy dissipation of these specimens. The results show that the aseismatic behavior of properly reinforced diagonally cross reinforced coupling beams is better than conventionally reinforced coupling beams, and this kind coupling beam can get no less than 3.5 chord rotation ductility at the 0.20 ratio condition of shear to compression. For diagonally crossing reinforced coupling beams with the small ratio of span to depth, the mechanism of the main force transfer system is the main diagonal strut tie model and stirrup truss model     

三丁基膦(TBP)和二硫苏糖醇(DTT)在秦川牛肌肉组织双向电泳中使用效果的差异及原因分析

合适的还原剂对蛋白的完全溶解以及较好双向电泳结果的获得至关重要。三丁基膦(tributyl phosphine,TBP)通常被认为是比二硫苏糖醇(DL-Dithiothreitol,DTT)更为有效的还原剂。本实验首次从图谱质量和蛋白分布两个方面,详细对比了TBP和DTT在秦川牛(Bos taurus)肌肉组织全蛋白和肌质蛋白双向电泳中的使用效果。结果表明,和TBP相比无论是全蛋白还是肌质蛋白,使用DTT作为还原剂的图谱背景均更为清晰,分辨率更高,对高分子量蛋白以及低丰度蛋白的提取也更为有效。因此,DTT比TBP更适用于秦川牛肌肉组织双向电泳。本研究的结果和传统的观点并不一致,初步分析了该原因,可能是TBP较短的半衰期导致了其在双向电泳中较差的使用效果。该实验为双向电泳的样品制备以及牛肌肉组织蛋白质组学研究提供了技术资料。     

"万力补"饲喂荷斯坦牛效果分析

将 2 0头泌乳后期的荷斯坦牛分成 4组 ,每组 5头。一组作为对照组 ,另外 3组作为试验组分 3个水平进行“万力补”饲料饲喂试验。结果表明 ,饲喂“万力补”对牛奶的 p H值、体细胞无明显影响 ,对乳脂率和乳蛋白有较明显的效果。在试验组的 3个水平中 ,以万力补添加量为2 0 0 g/头·d效果最好 ,产奶量提高 2 .30 kg/d。     

施肥、修剪和草种差异对草坪密度、越冬率和生长量的影响

通过试验研究施肥、修剪和草种差异对冷季型草坪草的密度、越冬率、累计生长量、根系深度等草坪评价因素产生的影响,比较不同草种和管理组合之间的差异,总结出对乌鲁木齐地区草坪管理适宜的施肥、修剪管理方式.     

忍冬科的系统发育核糖体DNA ITS区序列证据

以败酱草科Valerianaceae的Centranthu rubber为外类群,使用Phylip 3.65软件对忍冬科Caprifoliaceae 12个属12个代表种的ITS区序列进行了系统发育分析.采用最大简约法分析获得了5个最简约树,步长为580,一致性指数(CI)和维持性指数(RI)值分别为0.783 2和0.741 5.利用5个最简约树获取严格一致树.结果表明:①荚蒾属Viburnum与接骨木属Sambucus是姐妹群,自展支持率100%;并与忍冬科内七子花属Heptacodium、锦带花属Weigela构成姐妹群,虽然自展支持率为60%,从遗传距离上可看出荚蒾属与忍冬科内其他属之间仍有较近的亲缘关系,所以支持荚蒾属和接骨木属置于忍冬科内.②忍冬属Lonicera与鬼吹萧属Leycesteria聚成一小支,并构成姐妹群,自展支持率为100%;并与毛核木属Symphoricarpos、莛子镳属Triosteum构成姐妹群,自展支持率为100%,故不支持将毛核木属置于北极花族内Linnaceae;北极花属Linnaea、六道木属Abelia、猬实属Kolkwitzia、双盾木属Dipelta聚成姐妹群,自展支持率为100%,说明四者亲缘关系较近,仍置于北极花族内.     

Genetic structure of the oriental white stork (Ciconia boyciana): implications for a breeding colony in a non‐breeding area

The oriental white stork (Ciconia boyciana) is a threatened species, and their numbers are still in decline due to habitat loss and poaching. China is a breeding and main wintering area for this animal and in recent years some individuals have been found breeding in wintering areas and at some stopover sites. These new breeding colonies are an exciting sign, however, little is understood of the genetic structure of this species. Based on the analysis of a 463‐bp mitochondrial DNA (mtDNA) control region, we investigated the genetic structure and genetic diversity of 66 wild oriental white storks from a Chinese population. We analyzed the sequences of 66 storks obtained in this study and the data of 17 storks from a Japanese population. Thirty‐seven different haplotypes were detected among the 83 samples. An analysis of molecular variance showed a significant population subdivision between the two populations (F_ST= 0.316, P < 0.05). However, the phylogenetic analysis revealed that the samples from the different populations did not form separate clusters and that there were genetic exchanges between the two populations. Compared with the Japanese population, the Chinese population had a relatively higher genetic diversity with a haplotype diversity (hπ SD) of 0.953 ± 0.013 and a nucleotide diversity (π± SD) of 0.013 ± 0.007. The high haplotype diversity and low nucleotide diversity indicate that this population might be in a rapidly increasing period from a small effective population. A neighbor‐joining tree analysis indicated that genetic exchange had occurred between the newly arisen southern breeding colony and the northern breeding colony wintering in the middle and lower Yangtze River floodplain. These results have important implications for the conservation of the oriental white stork population in China.     

肉牛产业化需解决的几个关键问题

针对我国肉牛产业化水平低、经济效益差的现状，提出应着力解决以下几个关键性的问题：在全国范围内执行全国统一的肉牛胴体分级（评定）标准，以生产符合国际牛肉贸易要求的高档优质牛肉，获取高额利润，并迅速促进国内牛肉市场的发展；通过冷配杂交改良及胚胎移植等技术继续大力实施肉牛改良计划，大幅度地提高屠宰牛的胴体重；深入开展与肉牛有关的经济性状进行分子遗传机理的研究以及营养和牛肉品质等方面的研究。     

中国肉牛种业现状、存在问题及发展建议

 在全面分析中国肉牛种业产业现状的基础上,针对肉牛种业发展面临良种匮乏、良种繁育体系不健全、良种良法不配套、肉牛基础生产环节薄弱等的突出问题,论文提出了加强肉牛良种繁育体系建设,增加政府投入和宏观调控能力,加大科技创新和先进技术的推广以及加强育种人才和推广队伍的建设等发展建议。     

Snail家族基因功能研究进展

Snail家族基因编码具有锌指结构的转录因子,通过结合下游基因参与了多个生理水平的调控,在上皮-间质转化、胚胎发育、免疫调节、癌细胞迁移等方面具有广泛的生物学功能。Snail家族基因参与了脂肪的生成和脂代谢过程,同时也是肌生成决定因子(MyoD)的下游靶基因,也可能参与了肌肉发育调控。因此,Snail家族基因在脂肪生成、肌肉发育及脂代谢等方面发挥了重要作用,是影响哺乳动物特别是农业动物产肉性能和肉品质的一类重要候选功能基因。作者介绍了Snail家族基因及其蛋白结构和基本生物学功能,简述了Snail家族参与Wnt/β-catenin、Notch 等信号通路的调控作用方式,总结了Snail家族基因在哺乳动物脂肪生成和肌肉发育中的作用和调控方式。然而,目前关于Snail家族基因在协同参与哺乳动物脂肪生成和肌肉发育中扮演的角色仍待深入研究。另一方面,一般认为发挥转录抑制作用的Snail家族近年来也被发现具有转录激活作用,这种作用是如何实现的仍未知。因此,Snail家族基因在调控动物脂肪生成和肌肉发育过程中的协同作用、脂肪生成和脂肪水解过程的动态调控及其转录激活作用的发挥是今后研究的方向,为解析Snail家族基因在肉质性状形成过程中的遗传调控机理奠定基础。     

不同灌溉量对紫花苜蓿生长和品质的影响

水分不仅是构成紫花苜蓿的主要成分,还是影响苜蓿品质的重要因素.论文对紫花苜蓿在不同灌溉处理下的生物学特性以及品质进行了研究,结果表明第2茬苜蓿各生育期中干物质积累占总重百分比以开花期最大;各处理间各生育期的茎叶比均有显著差异;粗蛋白质、粗脂肪和粗灰分均与供水量大小呈正相关;粗纤维和酸性洗涤纤维与供水量呈极显著负相关;不...