5次交错群A_5的10阶子群的一个构造方法

A5的元最大阶数是5,使用有限群的Lagrange定理,A5的10阶子群元的阶只可能是2,5。但由于拉格朗日定理的逆不成立,因此是否存在A5的10阶子群仍是问题。该文通过对5-循环置换各次方幂的计算及其研究,找到A5的10阶子群元的构成规律,并使用构造性方法给出了5次交错群A5的6个10阶子群。     

RuCl2[P(C6H5)3]2(NH2CH2CH2NH2)催化苯乙酮加氢反应的研究

优化了以RuCl2[P(C6H5)3]2(NH2CH2CH2NH2)作催化剂催化苯乙酮加氢制备α-苯乙醇的反应条件,考察了反应温度、反应压力、碱的用量及不同的碱对反应的影响,得出了一个较好的反应条件.     

屈原与五月五日--端午的渊源及意义

春秋战国各国历法不一,五月五日禁忌原是北方晋、齐等国的习俗,后来才影响到全国,它原本与屈原没有关系.在汉末至南北朝时期,北方厌胜之术与南方救屈原结合起来,才形成了完整的端午节风俗.作为端午节重要内容之一的竞渡在唐代风行于南北,端午风俗在唐代才基本定型;端午使屈原永远活在民俗和民间文化中.     

一种基于VFP6.0的数据库加密算法

数据库管理软件的安全性、保密性非常重要。传统的加密方法有其局限性。本文介绍一种基于VISUAL FOX-PRO6.0的新型加密方法,其特点是:具有使用登记功能;每人一个密码,可随时更换;保密性强,密码不易被破解。     

THE INEFFICIENCY OF WORKER TIME USE

Much work is carried out in short, interrupted segments. This phenomenon, which we label task juggling, has been overlooked by economists. We study the work schedules of some judges in Italy documenting that they do juggle tasks and that juggling causally lowers their productivity substantially. To measure the size of this effect, we show that although all these judges receive the same workload, those who juggle more trials at once instead of working sequentially on few of them at each unit of time, take longer to complete their portfolios of cases. Task juggling seems to have no adverse effect on the quality of the judges' decisions, as measured by the percent of decisions appealed. To identify these causal effects we estimate models with judge fixed effects and we exploit the lottery assigning cases to judges. We discuss whether task juggling can be viewed as inefficient, and provide a back‐of‐the‐envelope calculation of the social cost of longer trials due to task juggling.     

食管癌患者健康相关生命质量研究

目的:探讨食管癌患者的健康相关生命质量现状及影响因素?方法:采用一般资料问卷?欧洲五维度健康评定量表(EQ-5D量表),对209例食管癌患者进行问卷调查,采用单因素分析和多因素分析探讨食管癌患者健康相关生命质量的影响因素? 结果:食管癌患者行动?自我照顾?日常活动?疼痛/不适?焦虑/抑郁五个维度存在问题的比例分别为18.2%?12.0%?22.0%?38.3%?25.4%;自评健康得分(VAS评分)为(75.20 ± 11.00)分;综合健康指数得分(Index得分)为(0.84 ± 0.22)分?患者的性别?家庭年收入?文化程度是VAS评分的主要影响因素;患者的年龄?治疗方式?肿瘤分期?医保类型是Index得分的主要影响因素?结论:实施心理干预?早诊早治?大病医疗保险有助于提高食管癌患者健康相关生命质量?     

Association between long-term erectile dysfunction and biochemical recurrence after permanent seed I125 implant brachytherapy for prostate cancer. A longitudinal study of a single-institution

We aimed to investigate the predictive factor of erectile dysfunction (ED) in prostate cancer (PCa) patients who underwent low-dose permanent I¹²⁵ seed implant brachytherapy and to investigate if ED could represent a patient’s reported outcome measures (PROMs) of efficacy of BT and indirectly associated with biochemical recurrence free survival (BRFS). From 2000 to 2012, 176 consecutive patients with low-risk PCa underwent BT. ED was evaluated with the International Index of Erectile Function (IIEF-5). Cox regression analysis was performed to assess significant predictors of mild-to-severe ED and BRFS after BT, including covariates. The 10-year actuarial rate of ED was 66%. Subjects with severe ED had higher values of D90 (183.0 versus 177.0; p?p?p?p?=?0.20), while D90?≤?180?Gy independently predicted BCR (HR: 4.65; [95%CI: 1.25–17.34]; p?125 implant, but it is not associated with better BRFS.     

Rao and Wu's re-scaling bootstrap modified to achieve extended coverages

Horvitz and Thompson's (HT) [1952. A generalization of sampling without replacement from a finite universe. J. Amer. Statist. Assoc. 47, 663–685] well-known unbiased estimator for a finite population total admits an unbiased estimator for its variance as given by [Yates and Grundy, 1953. Selection without replacement from within strata with probability proportional to size. J. Roy. Statist. Soc. B 15, 253–261], provided the parent sampling design involves a constant number of distinct units in every sample to be chosen. If the design, in addition, ensures uniform non-negativity of this variance estimator, Rao and Wu [1988. Resampling inference with complex survey data. J. Amer. Statist. Assoc. 83, 231–241] have given their re-scaling bootstrap technique to construct confidence interval and to estimate mean square error for non-linear functions of finite population totals of several real variables. Horvitz and Thompson's estimators (HTE) are used to estimate the finite population totals. Since they need to equate the bootstrap variance of the bootstrap estimator to the Yates and Grundy's estimator (YGE) for the variance of the HTE in case of a single variable, i.e., in the linear case the YG variance estimator is required to be positive for the sample usually drawn.     

Nonparametric control charts based on runs and Wilcoxon-type rank-sum statistics

In this article, we introduce three new distribution-free Shewhart-type control charts that exploit run and Wilcoxon-type rank-sum statistics to detect possible shifts of a monitored process. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of these charts is that, due to their nonparametric nature, the false alarm rate (FAR) and in-control run length distribution is the same for all continuous process distributions. Tables are provided for the implementation of the charts for some typical FAR values. Furthermore, a numerical study carried out reveals that the new charts are quite flexible and efficient in detecting shifts to Lehmann-type out-of-control situations.