The stress response factor RpoS is required for the natural transformation of Escherichia coli

The natural transformation of Escherichia coli is a novel and recently developed system that has significance for genetic studies and the biological safety of genetic engineering. However, the mechanisms of transformation, including development of competence and DNA uptake, are not thoroughly understood. In this study, we demonstrated the effect of the general stress response regulator RpoS, which has been associated with E. coli transformation, on natural transformation performed in an “open system”. We find that RpoS is required for natural transformation but not to artificial transformation and RpoS mainly affect transformation in the liquid culture prior to plating. In the liquid culture, RpoS over-expression promotes natural transformation in early exponential phase and static incubation accumulates RpoS and promotes transformation to a limited extent. These findings provide detailed understanding of RpoS function on natural transformation.     

The generalized partial transposition criterion for infinite-dimensional quantum systems

The positive partial transposition(PPT)criterion and the realignment criterion constitute two of the most important criteria for detecting entanglement.The generalized partial transposition(GPT)criterion which contains the PPT criterion and the realignment criterion as special cases,provides a necessary condition for a multipartite state to be separable.Here we extend the GPT criterion to the infinitedimensional multipartite(bipartite)case and show that it includes multipartite(bipartite)PPT criterion and multipartite(bipartite)realignment criterion as special cases as well.     

The tectonic uplift of the Hua Shan in the Cenozoic

Six granite samples were collected from six difference elevation locations at the Hua Shan in a main ridge of the Qinling Mountain. Apatite and zircon separated from these six samples were dated by the fission track technique. An assessment of the Cenozoic uplift or exhumation rate was obtained from the altitude difference of sampling samples dated by fission track, and from the difference of fission track dates of both apatite and zircon for a sample. The preliminary results suggest that the beginning of uplift of the Hua Shan was as early as 68.2 MaBP and the uplift rates for different periods are 0.02–0.19 mm/a (from the elevation difference) or 0.12–0.16 mm/a (from two mineral fission track dates). The average uplift rate is 0.12 mm/a (from the elevation difference) or 0.14 mm/a (from two mineral fission track dates). The uplift of the Hua Shan might accelerate since (17.8±2.0) MaBP, and the average uplift rate is about 0.19 mm/a.     

初始冲刷效应在农村雨水利用中的应用

通过理论分析暴雨径流初始冲刷效应的影响因素,提出在农村雨水利用中,通过控制集雨面的制作、加强集雨面的维护等措施,强化初始冲刷效应,以少量的初期雨水携带大部分的污染物,从而改善后蓄雨水水质。     

昆明酒店式公寓开发现状与对策研究

酒店式公寓以其＂酒店式的服务,公寓式的选择＂这一特质逐渐成为大众的选择、商家的投资热点。昆明酒店式公寓开发面临较好的机遇与选择,科学制定其开发策略,能有效提升昆明的品牌形象,促进其跨越式发展。     

以生为本理念下高校和谐师生关系的构建

面对不断出现的高校师生关系的错位,在科学发展观的指导下,以生为本构建和谐师生关系是当今高校必须面对的一个问题.师生关系的主体实现了和谐,师生关系实现的途径是和谐的,校园环境是和谐的,生本理念下高校和谐师生关系也就能成功地构建起来.     

思想文化也要独立：－我国文化发展战略中的一个关键问题

在经济全球的大背景中，从坚持艺的社会主义意识形态性质、坚持鲜明的民族传统和民族特点、坚持个人的独特品格等方面，阐述江泽民同志“思想化也要独立”的思想是一个具有化发展战略高度，坚持马克思主义价值观，为新时期社会主义艺的健康发展指明方向的重要思想。     

常村矿瓦斯涌出及治理现状分析

分析了目前常村矿瓦斯涌出和治理存在的问题，预测了接替采区瓦斯涌出量，利用通风方法能够治理的瓦斯区域和临界开采深度。     

思维方式的影响与作用

文化与思维对决策活动具有重要的影响和作用 ;文化背景不同 ,思维方式不同 ,决策主体应综合分析运用各种思维方式 ,以提高决策的科学化水平     

二踪示波器测量相位时的问题研究

提出了用二踪示波器使用１０倍衰减探头，在“外触发”状态下进行相位测量时所存在的问题，分析了引起这一问题的原因，并给出了解决这一问题的方法。