Study on pig growth hormone gene polymorphisms in western meat-type breeds and Chinese local breeds

Chinese Meishan and Jiangquhai pigs are two of the most prolific pigs in the world, but their growth rate is lower than that of Duroc, Landrace and Pietrain pigs. It is suggested that growth rate is regulated by growth hormone. The objective of the current study was to analyze the porcine growth hormone (pGH) gene polymorphisms based on the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP) for three western meat-type breeds (Duroc, Landrace and Pietrain) and two local Chinese pigs (Meishan and Jiangquhai). Five polymorphic restriction sites were detected with the ApaI, MspI, BspI and HhaI restriction enzymes in two amplified fragments (605 bp, -119 to +486; 506 bp, +206 to +711). Breed difference was found only in the 506 bp fragment. There was no difference in allelic frequencies of BspI and HhaI restriction sites among the five breeds (P>0.05). Landrace and Meishan pigs lacked allele G3 of MspI site. The allele G3 frequency of restriction MspI site of the 506 bp fragment in Pietrain pigs was higher than that in Duroc and Jianquhai pigs (P<0.001). For ApaI site, the Meishan pigs lacked allele G1; no difference was found in allelic frequencies among Pietrain, Duroc, Landrace and Jiangquhai pigs (P>0.05). This new and rapid PCR-RFLP typing method is an attractive tool for analysis of porcine growth hormone gene restriction sites. The differences in MspI and ApaI restriction sites may explain the growth difference between the foreign meat-type breeds above mentioned and local Chinese pigs.     

基于核密度估计多样性采集的背景建模算法

1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec…     

高职大学语文写作教学的缺失

高职大学语文课程设置的目的是培养和提高学生的语文素质和职业素质,因此应用写作能力的培养是不容忽视的,但当前高职大学语文课程写作教学却严重缺失,如教材中写作教学内容的缺乏、教师写作教学观尚未建立、学生写作能力的不足。解决这些问题的关键在于调整、改革大学语文课程,如将写作内容纳入大学语文课程中,课后进行各种写作训练,在语文教学中将写作与其他学科或实践互动,等等。     

关于青少年道德状况的思考

青少年素质教育要以德育为核心，以创新精神、实践能力为重点。围绕这个核心开展青少年的德育教育，是广大教育工作者的职责。为此，我们要了解当前影响青少年道德教育的诸因素，树立以人为本的教育思想，提高德育教育的水平。     

DSU报复制度的显著改进及我国的应对策略

传统国际法上的报复多以单边报复形态存在，滥用现象十分严重，威胁和损害到正常的国际法律秩序。由于存在着制度上的缺陷，GATT不仅未能从根本上解决报复滥用问题，而且限制了报复威慑作用的发挥。DSU通过改进规则和程序，强化多边体制，不仅充分地发挥了报复的威慑作用，而且还有效地管制了报复。该制度会给我国WTO争端解决的实践产生直接或者间接的影响，我们应认真研究应对策略，以维护我国的贸易利益和经济安全。     

利用V函数研究非线性系统解的稳定性

该文用李雅普诺夫(Liapunov)的第二方法分析了一类三阶非线性微分系统x φ(x)f(x) g(x) h(x)=0(1)零解的稳定性。在常系数线性系统的李雅普诺夫函数的基础上,通过变换找到该系统的等价线性系统,采用线性类比的方法构造出合适的李雅普诺夫函数,从而得出了这个系统的零解是渐近稳定的一组充分条件。     

中学英语单词与大学英语单词互相衔接的调查与研究

文章通过对中学生英语词汇学习的调查,了解中学生学习词汇的情况,并针对大学生英语词汇学习的现状,提出了中学英语单词与大学英语单词互相衔接的重要性以及做好衔接工作的一些建议。     

论不正当竞争行为及法律对策

社会主义市场经济应该在依法、公平、有序的秩序下开展竞争。发挥好市场竞争机制的作用,使社会有限的资源达到最合理有效的配置,对尽快建立比较完善的社会主义市场经济体系具有不可低估的作用。不正当竞争行为既为商业道德所不容,也被法律所禁止。本文将就不正当竞争行为展开论述,并提出相应的法律对策。     

Modeling water and carbon fluxes above summer maize field in North China Plain with back-propagation neural networks

INTRODUCTION Dynamics of carbon and water vapor fluxesexchange between the atmosphere and the ecosystembiosphere, depend on complex and non-liner interplayamong physiological, ecological, biochemical andedaphic factors and meteorological conditions (Jarvis,1995; Leuning et al., 1995). There are many studiesquantifying the fluxes across different time and spacescales as well as assessing the environment con-straints on them by some kinds of biophysical orempirical models whose resul…     

浅析网络教育与传统教育优势互补关系

网络教育和传统教育应当是一个有益的互补的关系，认识到这一点有利于我们坚定网络教育发展的信心，同时又有利于网络教育的发展。我们应从与传统教育互补的角度来精心策划和整合，以保证网络教学的质量和优势，避免目前网络教育发展中的盲目炒作和建设；同时正确对待网络教育的冲击，注意信息技术在教育中的应用。