Single-nucleotide polymorphisms in the public domain: how useful are they?

There is a concerted effort by a number of public and private groups to identify a large set of human single-nucleotide polymorphisms (SNPs). As of March 2001, 2.84 million SNPs have been deposited in the public database, dbSNP, at the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/SNP/). The 2.84 million SNPs can be grouped into 1.65 million non-redundant SNPs. As part of the International SNP Map Working Group, we recently published a high-density SNP map of the human genome consisting of 1.42 million SNPs (ref. 3). In addition, numerous SNPs are maintained in proprietary databases. Our survey of more than 1,200 SNPs indicates that more than 80% of TSC and Washington University candidate SNPs are polymorphic and that approximately 50% of the candidate SNPs from these two sources are common SNPs (with minor allele frequency of > or =20%) in any given population.     

清吟与哀唱－－论姚燮词两种心曲的认识价值

姚燮的《疏影楼词》和《续疏影楼词》抒写了他的两种不同心曲。《疏影楼词》中的闲放、闲冶、闲愁是青年姚燮在社会尚处承平时代生活和心续的写照。《续疏影楼词》中的凄苦、悲凉、颓丧,是中晚年姚燮在社会极荡转型时期情怀的释放。姚燮的两种心曲代表着与之同时代的主要传统士在社会承平和极荡不同时期的不同心境。姚燮的两种心曲,对帮助我们认识鸦片战争后晚清知识界的状态有着重要的参考价值。     

立式水冷器污垢自动清洗扭带结构优化研究

介绍了立式水冷器在工业上的使用现状,阐述了纽带自动清洗污垢的原理,着重对纽带,对传热性能影响结构进行了优化试验及讨论。     

Polycystins 1 and 2 mediate mechanosensation in the primary cilium of kidney cells

Several proteins implicated in the pathogenesis of polycystic kidney disease (PKD) localize to cilia. Furthermore, cilia are malformed in mice with PKD with mutations in TgN737Rpw (encoding polaris). It is not known, however, whether ciliary dysfunction occurs or is relevant to cyst formation in PKD. Here, we show that polycystin-1 (PC1) and polycystin-2 (PC2), proteins respectively encoded by Pkd1 and Pkd2, mouse orthologs of genes mutated in human autosomal dominant PKD, co-distribute in the primary cilia of kidney epithelium. Cells isolated from transgenic mice that lack functional PC1 formed cilia but did not increase Ca(2+) influx in response to physiological fluid flow. Blocking antibodies directed against PC2 similarly abolished the flow response in wild-type cells as did inhibitors of the ryanodine receptor, whereas inhibitors of G-proteins, phospholipase C and InsP(3) receptors had no effect. These data suggest that PC1 and PC2 contribute to fluid-flow sensation by the primary cilium in renal epithelium and that they both function in the same mechanotransduction pathway. Loss or dysfunction of PC1 or PC2 may therefore lead to PKD owing to the inability of cells to sense mechanical cues that normally regulate tissue morphogenesis.     

初中新生入学适应的发展研究

经纵向研究发现：初中新生的入学适应水平并非随时间的推移逐渐提高,而是呈“V”型趋势发展,即由适应——不适应——适应的过程发展,且各维度的适应水平也不平衡．学校和教师应根据新生的入学适应特点和发展规律,适当延长入学教育指导时间,重视入学后第二、三个月的适应指导,对症下药,走出入学适应指导误区。     

噪声干扰对机载雷达系统效果评估和建模

选取干扰破坏因子作为评估标准,解决了自卫干扰和多架远距离支援干扰飞机下,多普勒噪声或调幅、调频噪声干扰对PD、脉冲机载雷达效果评估问题。在雷达方程和干扰方程基础上建立了数学模型,并用MATLAB实现,特别是远距离支援干扰考虑了斯韦林目标模型、大气、降雨影响,计算结果表明:不同的斯韦林目标模型下干扰破坏因子相同;噪声功率密度越大,干扰破坏因子就越大,即雷达探测距离减少的倍数增大。     

P2×C5的全染色

令Pm=u1u2...um,Cn=ν1ν2...vnν1,则定义图Pm×Cn,(m≥2,n≥3)为V(Pm×Cn)={wij|i=1,2,…,m;j=1,2,…,n},E(Pm×Cn)={wijwrs|wij,wrs∈V(Pm×Cn),且i=r,νjνs∈E(Cn)或j=s,νiνr∈E(Pm)}.从而得到了图P2×C5的全色数.     

H∞ control for stochastic systems with time-delay

The H∞-control problem of stochastic systems with time-delay is considered. The sufficient conditions are obtained, under which there are always state-feedback control and dynamic output-feedback control so that the resulting closed-loop system is internaly stable and L2 input-output stable in the sense of expectation. Furthermore, the explicit formulas of both kinds of controls are derived. An example is included to illustrate the correctness of theoretic results.     

世界一流大学研究综述

随着中国建设世界一流大学政策的出台,学界从不同层面、不同角度,展开了对我国建设一流大学的探索和研究。作为一个重大而又全新的问题,中国建设世界一流大学理论研究取得许多重大的、有意义的成果,体现了学界对大学理想与理想的大学的深刻反思。本文概述其主要观点。     

工科研究生教育现存问题及解决方法

我国研究生教育规模连续六年快速增长,令人欣喜,但也存在一些问题,本文作者以亲身体会试论了当前工科研究生教育存在的问题及解决方法。