Tertiary structural differences between microbial serine proteases and pancreatic serine enzymes.

Although primary structural homology between bacterial serine proteases and those from the mammalian pancreas is slight, two-thirds of the residues in the bacterial enzyme SGPB as seen at 2.8-A resolution, adopt a similar polypeptide chain conformation to that of the chymotrypsin family. The three major regions of difference show how this family of proteolytic enzymes has developed from the more primitive bacterial to the relatively sophisticated pancreatic enzymes.     

A novel viral oncogene with structural similarity to phospholipase C

Numerous oncogenes have been isolated from acutely transforming retroviruses. To date, the products of these viral oncogenes have been protein kinases, nuclear proteins, growth factors, or GTP-binding proteins. We have cloned the previously uncharacterized avian sarcoma virus CT10 and sequenced its genome. This virus encodes a protein, p47gag-crk, that has blocks of sequence similarity to the amino-terminal, non-catalytic region of the non-receptor class of tyrosine kinases. In addition, the structure of p47gag-crk has striking similarity to a 180-amino acid region of bovine brain phospholipase C. Biochemical data suggest that p47gag-crk activates one or several endogenous tyrosine kinases.     

一类n值命题逻辑系统中改进的相似度及伪距离

基于均匀概率空间的无穷乘积在一类n值命题逻辑系统中定义了公式的真度,并利用真度给出一种改进了的相似度定义,进而导出全体公式集F(S)上的一种伪距离,最后讨论了相似度及伪距离的重要性质.     

一种基于结构相似度的IHS与小波变换相结合的遥感影像融合算法

针对分别使用IHS变换和小波技术进行融合实验时有较大的色彩畸变的问题,提出了一种基于结构相似度的IHS与小波变换相结合的融合算法.首先对多光谱影像进行IHS变换,对多光谱影像的亮度分量Ⅰ和全色波段影像进行小波分解;然后采用二者高频系数绝对值较大者作为新的Ⅰ分量的高频系数,而新的Ⅰ分量的低频系数由二者的低频系数进行加权平均获得,权值通过计算Ⅰ与全色波段的SSIM来自适应地确定.实验结果表明该算法在提高影像分辨率的同时,能很好地保持影像的光谱特征.     

一种由三角模所诱导的粗糙集间的相似性度量方法

给出两粗糙集间一种新的相似度计算方法,并将其应用到模糊模式识别问题中,通过算例说明这种方法的可行性和有效性.     

"仁爱"与"兼爱"的异同

针对春秋战国时期混乱的社会局面,孔子和墨子提出了不同的见解."仁爱"与"兼爱"的对立并不在于"爱有差等"和"无差别之爱",相反,在这一点上,他们是一致的,真正的分歧在于前者从人之为人的道德理性寻找理论的依据,而后者把目光投向了经验世界的"实利",前者主张"己所不欲,勿施于人",而后者主张"己所欲,施于人",前者体现了主体间的尊重与平等,后者常常造成适得其反的结果.     

一类面板模型中部分结构变点的检测和估计

给出了解决面板回归模型中存在未知部分结构变点时的检测、估计和推断问题的新方法,得到了结构变点的相合估计及渐近分布。基于最小二乘方法构造全局最小残差平方和,并用于检测结构变点。该方法适用于纯结构变点模型和部分结构变点模型,并且即使面板数据只有很少的个体,估计的相合性也可保证。Monte Carlo模拟结果验证了理论的正确性。基于中国股票市场上参与股改的404家工业企业的实证研究表明:应首先检测结构变点是否存在,然后才能分析解释数据;忽略检测结构变点会产生有偏估计,甚至出现伪回归。     

结构效益与结构变动关系研究——以泰安市工业为例

本文采用文[1]提供的方法,利用经济普查资料,对泰安市工业结构调整效益进行了测定.通过分析,发现泰安工业结构效益总体水平不高,分布不均衡.同时,还探讨了工业结构利益转移与结构变动之间的关系.     

基于广义邻域结构相似度的红外和彩色可见光图像融合

针对 HIS 空间各通道间不具有正交性,导致基于该颜色空间的图像融合中颜色畸变较明显,而 lαβ彩色空间具有感知去相关性,结合非下采样 Contourlet 变换系数在不同尺度、方向和位置间具有很强的依赖性,提出一种基于广义邻域结构相似度的红外和彩色可见光图像融合法,首先将彩色可见光图像转换到 lαβ空间,利用非彩色通道对红外图像重映射;然后 NSCT 分解非彩色通道和重映射图像,对低频系数采用不同融合规则比较,高频子带采用综合同尺度中邻域系数能量和兄弟子带间的结构相似度的融合规则,重构 NSCT 融合系     

不同物种间乙酰辅酶A羧化酶的差异性和相似性

采用生物信息学方法对GenBank, SwissProt中的拟南芥、大豆、甘蓝型油菜、小麦等物种的乙酰辅酶A羧化酶核苷酸和氨基酸序列进行了比对分析,进而对其组成成分、理化性质、疏水性/亲水性、跨膜结构域、蛋白质二级结构、功能结构域、三级结构数进行了预测和分析.结果表明： ACC基因具有完整的开放阅读框,长约50683 bp,编码氨基酸相对分子质量为93.41 kD,理论等电点为7.27,是亲水性不稳定蛋白,二级结构均以α-螺旋和不规则卷曲为主要构件.通过进化树分析可分别将8种生物分为2组： A支包括小麦等7个物种,B支仅含甘蓝型油菜.     

一种与核黄素合酶α亚基具有结构相似性的板蓝根多肽的分离纯化与表征

利用离子交换色谱SP-5PW和疏水色谱POROS HP2从板蓝根鲜根水相抽提物中分离纯化多肽组分,并对其进行生化表征.获得一种达到电泳纯的多肽RIP2,其相对分子质量约为6.87 ku,等电点约为7.73,N端氨基酸序列依次为QIGEFATAPF.经数据库搜索比对,发现该多肽与核黄素合酶α亚基具有一定的同源性.细胞毒性实验表明该多肽具有一定抗病毒作用.     

A measure of semantic similarity between gene ontology terms based on semantic pathway covering

Semantic similarity between Gene Ontology (GO) terms is critical in resolving semantic heterogeneousness when integrating heterogeneous biological databases. Traditionally, distance based and information content based measures are two major methods. In this paper, a new method based on semantic pathway covering is proposed and an algorithm, COMBINE algorithm, is presented, which considers information contents of two given nodes and those of all nodes included in the two nodes’ pathways. Experiments show that COMBINE algorithm obtains the highest correlation index compared with those distance based and information content based algorithms.     

A class of ebe time integration algorithms for transient finite element structural dynamical analysis

A new class of algorithms for transient finite element structural dynamical analysis which is amenable to an efficient implementation in parallel computers (especially Massively Parallel Computers) is proposed. The suitability of the method for parallel computation stems from the fact that, given an arbitrary partition of the finite element mesh, each element in the partition can be processed over a time step independently and simultaneously with the rest, and no global equation solving effort is involved. Although the proposed EBE time integration algorithms are shown to have the structure of an explicit scheme, they are unconditionally stable over a certain range of the algorithmic parameter.     

三产业增加值与中等职业教育的关系研究

基于偏最小二乘法,对国内生产总值中三产业增加值与各类中等职业教育的关系进行了建模和定量分析,结果显示:普通中专和成人中专对各产业的促进作用存在不同程度的差异,优化和改善其人才培养的结构将有利于三产业的协调发展;职业高中和技工学校对产业的促进作用急待增强,提高和加强人才培养的数量和质量将有利于各产业经济的快速发展。     

稠密性对微尺度与稀薄气体流动相似性的影响

基于Enskog稠密气体理论,通过考察密度对气体物性及流动特性的影响,分析了微气体流动与稀薄气体流动相似性成立的条件.结果显示,若微气体流动中需要考虑稠密性对气体物性和宏观流动参数的影响时,表征微气体流动和稀薄气体流动的3个量纲一的特征数(Kn、Re和Ma)不可能同时对应相等,两种流动不可能相似.研究了稠密性对徽气体流动特性和输运系数的影响,同时,分别以基于稠密气体理论的声速相对偏差小于5%和基于热力学分析的压力相对偏差小于0.5%为限,计算得出各种气体在两种流动相似性失效时的密度值.     

Genetic similarity between mates and extra-pair parentage in three species of shorebirds

Matings between close relatives often reduce the fitness of offspring, probably because homozygosity leads to the expression of recessive deleterious alleles. Studies of several animals have shown that reproductive success is lower when genetic similarity between parents is high, and that survival and other measures of fitness increase with individual levels of genetic diversity. These studies indicate that natural selection may favour the avoidance of matings with genetically similar individuals. But constraints on social mate choice, such as a lack of alternatives, can lead to pairing with genetically similar mates. In such cases, it has been suggested that females may seek extra-pair copulations with less related males, but the evidence is weak or lacking. Here we report a strong positive relationship between the genetic similarity of social pair members and the occurrence of extra-pair paternity and maternity ('quasi-parasitism') in three species of shorebirds. We propose that extra-pair parentage may represent adaptive behavioural strategies to avoid the negative effects of pairing with a genetically similar mate.     

中西方学习文化研究对大学英语教育的启示

旨在探讨中西方学习文化差异及其对大学英语教育的启示.在英语教育过程中,应该从中国的文化与教育实际出发,融合中西方学习文化的有利因素,从而有效提高中国大学英语教育的质量.     

一类排列的计数问题

应用容斥原理解决了不含连续数对的一系列排列的计数问题。并将其进行了推广。