遗传上根和超幂零根与其补根成偶的条件

设M是一个环类,令∪M={A|(?)O≠A/I,A/I(?)M}.H∪M={A|(?)O≠I△△A,(?)O≠A/J,I/J(?)M}本文证明了当M是r一环类时,H∪M是含在∪M中的最大遗传根,我们称之为由M决定的遗传上根。利用遗传上根,我们给出了超幂零根S与补根S′形成根偶的几个充要条件。     

矩阵的秩与其非零特征值个数相等的条件

证明了n阶方阵A的秩r(A)与其非零特征值个数μ(A)之间的关系:r(A)≥μ(A).得出了矩阵A可逆和矩阵A可对角化是r(A)=μ(A)的两个充分条件;矩阵A没有形如xm(m2)的初等因子是r(A)=μ(A)的充分必要条件.     

Homogenization of attractors for a class of nonlinear parabolic equations

1IntroductionandmainassumptionsLetT>0and?beanopenboundedsetofRnwithboundary??.Considerthefollowinginitialboundaryvalueproblem??tuε??divA(x,x,?uε)?g(x,uε)=f(x)in?×(0,T),(Pε)??uε=0εεon??×(0,T),?uε??(x,0)=u0in?,whereA(x,,?uε)xεandg(x,uε)εaresubjecttoappropriateassumptions.Twoaspectsoftheproblem(Pε)havebeenstudiedbymanyscholars.Oneistheexistenceoftheglobalattractorfor(Pε),whichisanimportantobjecttodescribethelongtimedynamicsofthecorrespondinginfinitedimensionalsystem.Theotheris…     

Global attractors of a degenerate parabolic equation and their error estimates

The existences of the global attractor A^ε for a degenerate parabolic equation and of the homogenized attractor A^0 forthe corresponding homogenized equation are studied, and explicit estimates for the distance between A^ε and A^0 are given.     

Effect of microcystin-LR on protein phosphatase 2A and its function in human amniotic epithelial cells

Due to their toxicity, the increased distribution of microcystins (MCs) has become an important worldwide problem. MCs have been recognized as inhibitors of protein phosphatase 2A (PP2A) through their binding to the PP2A catalytic subunit. However, the exact mechanism of MC toxicity has not been elucidated, especially concerning the cellular response and its autoregulation. To further dissect the role of PP2A in MC-induced toxicity, the present study was undertaken to determine the response of PP2A in human amniotic epithelial (FL) cells treated with microcystin-LR (MCLR), one of the MC congeners. The results show that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity, and a high-dose treatment of MCLR for 24 h decreased the activity of PP2A, as expected. The increased mRNA and protein levels of the PP2A C subunit may explain the increased activity of PP2A. Furthermore, MCLR altered microtubule post-translational modifications through PP2A. These results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity of MCLR.     

Reviews

A is for Aesthetic: Essays on Creative and Aesthetic Education PETER ABBS Education for Crafts: A Study of the Education and Training of Craftspeople in England and Wales C. ASHWIN, A. CHANNON, J. DARRACOTT Color Theory and Its Application in Art and Design GEORGE A. AGOSTON Cézanne's Early Imagery MARY TOMPKINS LEWIS     

企业并购后风险及其识别研究

企业并购后风险的有效识别与防范是决定企业并购能否最终成功的关键要素。本分析了企业并购后风险的特点与主要类型，讨论了并购后风险识别的一般程序，对可适用于并购后风险识别的主要方法及其运用过程进行了研究。     

Stability of overt Type A behaviors in children: results from a one-year longitudinal study

This paper describes the degree of similarity between repeated ratings (taken 1 year apart) of overt Type A behaviors in 2 samples totaling 633 children. The measure of overt Type A behaviors was the Matthews Youth Test for Health (MYTH), which was completed by the children's classroom teacher. Results showed that correlations between repeated MYTH ratings approximated .55 and in general increased somewhat with the children's school grade, although correlations between repeated ratings of competitive achievement behaviors of boys residing in an affluent eastern suburb were somewhat lower than above. The degree of similarity across 1 year in children's Type A behaviors is comparable to that found for adult Type A behaviors and for other cardiovascular risk factors in children. The discussion includes a consideration of assumptions underlying research on the origins of Type A behavior and suggests that etiological factors in the development of Type A might profitably be studied in primary school-aged children.     

关于双图的群染色（英文）

若图G=（V,E）,给定方向为D,A表示一个非平凡的阿贝尔群,F（G,A）表示映射f：E（G）→A的集合.若对任意f∈F（G,A）存在映射c：V（G）→A,使得G中的每一条有向边e=uv∈E（G）（方向是u→v）满足c（u）-c（v）≠f（e）,这时说图G是A-可染的.使得图G在方向D下是A-可染的,A的最小阶数为图G的群色数,记为χg（G）.主要是在分析了一些双图的特性的基础上讨论了它们的群色数.对于任意阶路的双图可得出其群色数都是3,还证明了圈的双图的群色数不超过5以及得到其它一些双图的群色数的上界.     

矩阵左半张量积的特征值不等式

首先给出了任意两个复矩阵做左半张量积的特征值的不等式。然后给定两个（半）正定矩阵A、B以及它们的特征值,给出了矩阵A、B的左半张量积的特征值不等式以及一个精确估计,得到了一个不断缩小A×lB特征值的下、上限间距离的方法．     

IT in Mathematics across the Curriculum—NCET

Book reviewed in this article: P'raps, P'raps Not By Mary Brading and Michelle Selinger Statistics AEB Maths for AS and A level By David Cassell, Ian Hardwick, Mary Rouncefiled and David Burghes Further Statistics AEB Mathematics for AS and A Level By John White and Roger Williams Heinemann Modular Mathemtics for London AS and A Level Statistics 2 By Greg Attwood and Gill Dyer Understanding Probability and Statistics: A Book of Probliems By Ruma Falk     

U3A Online: a virtual university of the third age for isolated older people

U3A Online is a virtual university of the third age (U3A) that provides intellectually challenging courses for isolated older people as well as for conventional U3A members. Volunteers run the programme and all courses are written and led by retired people, principally for third-agers who are isolated by distance or circumstance from taking part in conventional face-to-face U3A activities. This paper reports on two studies that were designed to reveal some of the characteristics and aspirations of participants in the U3A Online programme. During the proof-of-concept pilot study, run in 1999, telephone interviews and pre- and post-course written questionnaires were used. A sample of ‘experienced’ course members provided written data by questionnaire for the 2001 survey. The studies show that many participants who are unable to take part in mainstream adult education activities attribute a new sense of purpose and excitement in their lives to the virtual communities they begin to develop through their online courses.     

Differential conditioned suppression in the Konorski-Lawicka paradigm

In conditioned suppression discriminations, the Konorski-Lawicka paradigm involves A+ trials, where conditioned stimulus A is followed by shock, and sh → A? trials, where A is preceded by shock Rats easily mastered this A+/sh → A? discrimination, as indicated by suppression of food-reinforced barpressing on A+ trials and acceleration of barpressing on sh → A? trials. A history of A+ conditioning resulted in nearly perfect discrimination performance on the very first day of A+/sh → A ? training, but a history of sh→ A? conditioning retarded development of the discrimination. The basis for the development of the discrimination was discussed in terms of an inferred stimulus (sh′) arising from the aftereffects of shock.     

与给定矩阵A的可交换子环C(A)的一些探讨

收集整理现在常用的高等代数与线性代数材料中与给定矩阵A可交换的矩阵所构成的全矩阵空间Pn×n的子空间C(A)的习题,指出CA的交换性及用A的多项式表示问题同C(A)的维数与n有密切关系,得到n(n叟3)阶幂等矩阵A或对合矩阵A的CA都是不可交换的结论。     

Practitioner Perceptions of the A3 Method for Process Improvement in Health Care

The focus of this article is to present students' perceptions of the recently developed A3 method, a structured problem-solving approach based on lean concepts and tools that have been adapted to the health care environment. The students were all employees of a large health care provider and were enrolled in a customized health care executive MBA Program. Each student was required to complete an individual A3 Project in order to improve a process at the department for which they worked. At the end of the semester the students presented their A3 projects to their peers who voted on the best projects. A survey measuring perceptions of the A3 method for problem solving in health care was administered and from it we present propositions for A3 implementation. These propositions are applicable both to health care practitioners and to academic researchers.     

Reviews

Books reviewed in this article:
The Review Reviewed, A Reply to Brady
Michael Krausz, Rightness and Reasons
James S. Kaminsky, A New History of Educational Philosophy
William Hare, What Makes A Good Teacher
Arthur G. Wirth, Education and Works for the Year 2000: Choices We Face
Elmer John Thiessen, Teaching for Commitment     

矩阵的Khatri-Rao与Tracy-Singh乘积的几何平均

对分块实对称正定矩阵A，B，C和D，证明了一个矩阵等式( A ⊙ B ) # ( C ⊙ D ) = ( A # C ) ⊙ ( B # D )，这里A ⊙ B和A # B分别是A与B的Tracy-Singh乘积和几何平均，如果A和B是分块实对称矩阵，则有矩阵不等式 ≥ ，其中是矩阵和的Khatri -Rao乘积。     

对外汉语教学中“没A没B”与“无A无B”之辨

本文在举出大量语言实例基础上,考察了＂没A没B＂和＂无A无B＂两种语型,分别在结构、语义、声调三个方面进行了辨析,以便在汉语教学中更好地帮助外国学生理解和运用。两种语型都可以做谓语、定语、状语,皆可转换成＂没AB＂＂无AB＂的形式,且都具开放性和能产性。＂没A没B＂偏向口语化,多含贬义色彩,＂无A无B＂偏向书面语,可表示贬义也可以含褒义色彩。＂没A没B＂表示斥责或抱怨时,最后一个字常为三声（上声）,调值为214的较多。包含褒义或中性义时,＂无A无B＂中最后一个字,常为四声（去声）,调值为51的较多。AB的声调大多都遵循＂阴阳上去＂的顺序。     

Detecting Differential Item Functioning Using Logistic Regression Procedures

A logistic regression model for characterizing differential item functioning (DIF) between two groups is presented. A distinction is drawn between uniform and nonuniform DIF in terms of the parameters of the model. A statistic for testing the hypothesis of no DIF is developed. Through simulation studies, it is shown that the logistic regression procedure is more powerful than the Mantel-Haenszel procedure for detecting nonuniform DIF and as powerful in detecting uniform DIF.     

基于平衡同时Schur分解的联合特征值估计

讨论可交换单纯矩阵族A的联合特征值估计问题.为了克服基于同时Schur分解和酉变换算法的收敛和性能分析缺陷,提出了一种基于同时相似对角化的联合特征结构估计算法.该算法通过对A交替进行同时Schur分解和范数平衡来实现矩阵族的对角化.该算法的有效性在于:每个子过程在优化自身代价函数的同时,还对另一子过程的收敛起到加速作用.在适当的假设条件下,可以证明该算法交替优化的2个代价函数(矩阵族范数和矩阵族下三角元素范数)的收敛性.基于多维谐波提取的数值仿真显示该算法在矩阵族偏离正规阵时收敛速度显著快于基于同时Schur分解和酉变换算法,并且联合特征值的估计性能可以进行简洁的闭式分析.