双曲运动群的单参数子群及其轨道

本文通过研究双曲平面H~2上运动群的单参数子群及其分类,单参数子群的轨道曲线的几何性质,得到如下主要结果:定理1 双曲平面H~2上运动群G的单参数子群就是H~2上的旋转群,或平移群,或平行位移群;反之亦然.定理2 在双曲平面H~2上,运动群G的单参数子群的每个轨道或是一个点,或是一条常(测地)曲率曲线.其逆亦真.     

局部对称黎曼流形中具有平行中曲率向量的子流形

设Nn + p是截面曲率KN 满足 12 <δ≤KN≤ 1的n +p维局部对称完备黎曼流形 ,P≥ 1.M是Nn + p的具有平行中曲率向量的n维紧致子流形 ,本文讨论了这类子流形关于第二基本形式模长平方的积分不等式及其Pinching问题 .     

混合径向平均体在积分变换下的性质

As a generalization of RpK, the mixed radial p-th mean bodies Rp(K,L, μ) have many properties similar to RpK. In this paper, some properties of Rp(K,L, μ) such as monotonicity, transform properties under volume-preserving lineartransformations, etc. were studied. By using the polar coordinate formula for volume and Fubini’s theorem, V (Rn(K,L, μ)) =V (L) was obtained.     

伪黎曼空间型中具有常平均曲率的类空子流形

本文研究了伪黎曼空间型中具有常平均曲率的类空子流形,得到了这类空子流形的一个积分不等式及刚性定理。     

浅析中国传统文化在企业管理中的影响

中国传统文化博大精深,它指导国人行为两千多年。在全球经济一体化的今天,中国传统文化也不可避免的影响着企业管理行为。关于管理者在企业中如何更好地运用中国传统文化来进行管理,文章给出了一定的诠释。     

积分中值定理注记

在本文中,我们讨论了积分中值定理的应用中应注意的一些问题,得到了几个有意义的结果。     

On repeated measures designs: Hierarchical structures and time trends

The basic anatomy of an experimental design is used as an expository introduction to the examination of several repeated measures experiments described in recent pages of this and other journals. This examination reveals problematic issues concerning some common design and analysis features of such experimental designs. In particular, the hierarchical structures and/or presence of time trends is highlighted. These issues are discussed in an attempt to assist researchers to recognize such problems, to avoid the associated difficulties in the future, and to exploit the advantages of sound design with appropriate, efficient and informative analysis. While alternate reanalyses of the data of these experiments might reveal the conclusions to be unaffected by such issues, researchers should still be cautious. In retrospect, such occurrences should be seen as fortuitous, not as justification for inefficient or less informative analyses. More importantly, such reanalyses could reveal more enlightening information, and I argue that if a design permits such information to be discovered, then it behoves researchers to perform such analyses and to make such discoveries.     

交叉关联噪声与时间延迟对肿瘤细胞生长过程的影响

运用随机数值模拟方法,研究了内噪声和外噪声驱动的时滞Logistic模型描述的肿瘤细胞生长系统的瞬态性质.数值模拟结果表明,噪声间的关联强度λ、系统的延迟时间τ、乘性噪声强度α的增大均能使系统的平均首通时间T下降,即加速肿瘤细胞的消亡过程,降低系统的稳定性;在时间延迟与关联噪声的相互作用下,随着τ的增大,出现了τ抑制λ和α对肿瘤细胞衰减过程加速作用的现象;此外,噪声间的负关联也能抑制较大的τ和较小的τ对T的影响.     

A Simple Equation to Predict a Subscore's Value

Subscores are often used to indicate test‐takers' relative strengths and weaknesses and so help focus remediation. But a subscore is not worth reporting if it is too unreliable to believe or if it contains no information that is not already contained in the total score. It is possible, through the use of a simple linear equation provided in this note, to determine if a particular subscore adds enough value to be worth reporting.     

An NCME Instructional Module on Subscores

The purpose of this ITEMS module is to provide an introduction to subscores. First, examples of subscores from an operational test are provided. Then, a review of methods that can be used to examine if subscores have adequate psychometric quality is provided. It is demonstrated, using results from operational and simulated data, that subscores have to be based on a sufficient number of items and have to be sufficiently distinct from each other to have adequate psychometric quality. It is also demonstrated that several operationally reported subscores do not have adequate psychometric quality. Recommendations are made for those interested in reporting subscores for educational tests.