Separating psychological momentum from strategic momentum: Evidence from men’s professional tennis

In dynamic contests, strategic momentum and psychological momentum potentially coexist, which makes it difficult to distinguish between the two. We employ the setting of professional tennis, which allows us to separate psychological from strategic momentum. In tennis, converting a break point potentially triggers both strategic momentum—due to a change in the relative position of the players—and psychological momentum—due to a change in the perception of the players. To distinguish between these two momentum types, we employ exogenously given interruptions. Interruptions are predicted to affect psychological momentum negatively, while leaving strategic momentum unaffected. Using 4930 game-by-game observations from 141 Grand Slam men’s single matches, we show that the breaking players’ probability of winning a game increases after converting a break point, which provides evidence for momentum. Moreover, we show that this momentum effect is negatively affected by an interruption. Thus, psychological momentum seems to be the main trigger leading to a performance increase after a converted break point.     

Estimation of system reliability for exponential distributions based on L ranked set sampling

Abstract

In the case where strength and stress both follow exponential distributions, this paper considers the maximum likelihood estimator (MLE) of the system reliability based on L ranked set sampling (LRSS). The proposed MLE is shown to have existence, uniqueness and asymptotic normality, and its asymptotic variance is obtained by the Fisher information matrix of LRSS. The values of asymptotic relative efficiencies show that the proposed MLE is always more efficient than the MLE using simple random sampling (SRS). However, the MLE using LRSS cannot be written in closed form. Therefore, the modified MLE is proposed using the technique replaced some terms in the maximum likelihood equations by their expectations. The newly modified MLE using LRSS is shown to be superior to the MLE using SRS. Finally, the proposed method is applied to a real data set on metastatic renal carcinoma study.     

二维奇异非稳态问题有限元解的误差估计

二维奇异问题的有限元方法是实际中经常会遇到的一类问题,对其解决有重要意义.本文讨论二维奇异非稳态问题的有限元方法,证明了弱解的存在唯一性,并给出有限元解的加权L2-模估计.     

文化差异制约下的中国“西部镜像”——20世纪初域外探险者笔下的西部探险记游

19世纪末到20世纪初的外国探险者对中国西部的"地理大发现",是在中国沦为半殖民地的历史背景下发生的.因而,要对他们的探险记游所折射出的"西部镜像"给予科学审视和历史分析,既要珍视其独特的文化视角和文学价值,又不能回避其中因为文化差异而导致的偏见、局限与蔑视.因为,域外探险记游文学不仅仅是异域风情的展现与描绘,还包含着创作者的文化认知与主体心灵的展露,自然物象与主体形象的结合与呈现,才是这类作品的最高境界.     

Inferences concerning interpersonal choices given anonymously

It may be difficult or impossible to make a reliable empirical investigation of an unknown network of interpersonal choices or contacts if these are in some respect sensitive for the individuals involved. We consider how choice data given anonymously can be used to reveal various features of the network. Using tools from statistical decision theory and information theory we can determine risks and capacities of disclosing choice data, the graph structure of choice data and its numbers of loops and mutuals. We give some general results, illustrate the combinatorial complexity of the problem and comment upon the computational difficulties.     

关于82’宪法颁布实施20年来的回顾与评价

通过对82'宪法的立宪背景、制定过程及其修改内容等之简要回顾,展示了82'宪法的成长历程;通过对82'宪法历史地位的评价,在肯定82'宪法的历史意义的同时,指出了82'宪法的"美中不足"。     

新"轴心时代"的文明对话--论杜维明的"文明对话"观

亨廷顿"文明的冲突"理论一发表,在世界上就引起了很大反响.从一定意义上来说,杜维明的"文明对话"观是对这一思潮反映的产物.杜维明的"文明对话"观主要包含三个方面作为当代新儒家的主要代表,他通过对亨廷顿的"文明冲突"论的批评,揭示了文明对话的时代内涵;第二,他主要借助于雅斯培尔斯"轴心时代"理论,通过时启蒙反思和多元现代性论域的开展,论证了新轴心时代文明对话的可能性和必要性;最后,主要讨论文明对话的三种形态,指出新轴心时代文明对话的一些基本预设.     

第三届全国青年史学工作者学术会议综述

第三届全国青年史学工作者学术会议是世纪之交全国青年史学工作者的盛会。会上 ,代表们就 2 0世纪中国史学回顾、2 1世纪中国史学走向、历史学的定位及功能等问题展开了热烈地讨论 ,精彩纷呈。与会学者在中国古代史、中国近现代史、世界史等领域的一些专门问题上也发表了饱含深邃智慧的见解。     

二语习得中的母语负迁移简析

对二语习得的研究表明,母语迁移是影响第二语言习得的重要因素之一。本文通过对英汉两种语言的对比分析,从语音,词汇,语法,文化等诸多方面阐明母语迁移中的负迁移现象对二语习得的影响,并探究了在英语教学过程中如何尽量避免母语负迁移,以使二语习得者的语言能力得到有效提升。     

西方二语习得理论研究的两种认识论取向——对我国外语研究的启示

二语习得研究主要是科学系统地研究人们在习得了母语后是如何学会第二语言的.在二语习得研究中专家学者建构了很多二语习得理论.虽然这些理论对二语习得的本质、习得的过程及其影响因素关系的阐释和研究视角不同,但是可以概括为心灵认知主义和社会认知主义两种主要认识论取向.比较心灵认知主义取向的二语习得理论, 基于社会认知主义的二语习得理论为我国外语学习者的学习过程、学习动机、学习策略、社会文化环境等因素研究建立了理论基石,也为建构我国本土外语教学理论和教学实践提供了有利的理论支持.