关于正定矩阵方幂的讨论

本文指出了正定矩阵的方幂一般不是正定矩阵,并且给出了正定矩阵2~k次方幂为正定矩阵的一个充要条件。     

找寻女性生命的渡口--试析中篇小说《狮滩的妹儿有点恶》

今天,女性意识已经成为了人们日常话语的关键词。女人们开始从过去被男性话语的遮蔽、扭曲、误解中走出来,要求彰显她们存在的意义和价值,她们不断地改写着传统的两性话语权力关系。本文试图从三个方面来分析这部作品所包含的女性意识。     

Doreen Massey

The growth of transnational communications, most notably the Internet and email, has had a profound impact on social and political interactions across borders. Doreen Massey, a social and political geographer, has written widely about space, with an emphasis on examining relations between actors, rather than the roles that they play. Her research suggests that space can be conceived of as constructed of these relations and, as a consequence, power can be seen to operate at multiple and complex levels. This article examines Massey's work, identifying areas of particular relevance to communications scholars. Massey's thinking is applied to the contemporary communications arena, where her ideas on space and 'power-geometries' offer new insights into how the complexities of transnational relations can be understood.     

PB8.0中几种查询方法的讨论

对PB8．0中可以实施的几种查询方法加以介绍和讨论，为PB使用者提供一定的参考．     

Power to the people—health PR people that is!

Inspired by the seminal typology of power first suggested by French and Raven, this study identified five types of power (Expert, Information Reward, Information Coercive, Advertising Coercive, and Influence Powers) that health public relations practitioners believed they have in media relations. This study also examined the effect of four variables, such as personal closeness with reporters, openness towards the media, perceived media job performance, and perceived expertise in the health field, on these five types of perceived power. The results suggested that public relations practitioners who highly evaluate themselves as an expert in health and as a competent media communicator, and who are personally close with reporters have greater Expert Power in media relations. Also, when practitioners are personally close to reporters, they are more likely to use Information Reward Power.     

A Moment Preserving Finitization Across the Power Series Family of Probability Distributions

Finitization transforms a discrete distribution into a distribution with smaller support of specified size. In special cases finitization preserves moments (moments of the order n finitization coincide with those of the parent distribution). We create a moment preserving finitization method for power series distributions by introducing an alternative representation and showing how to finitize members of this new class in a manner that preserves moments of the parent distribution. We provide results on convolutions and a reproductive property for power series distributions that have been finitized in this manner, and show how these finitized distributions accelerate variate generation in simulation.     

Testing Predictive Ability and Power Robustification

One of the approaches to compare forecasting methods is to test whether the risk from a benchmark prediction is smaller than the others. The test can be embedded into a general problem of testing inequality constraints using a one-sided sup functional. Hansen showed that such tests suffer from asymptotic bias. This article generalizes this observation, and proposes a hybrid method to robustify the power properties by coupling a one-sided sup test with a complementary test. The method can also be applied to testing stochastic dominance or moment inequalities. Simulation studies demonstrate that the new test performs well relative to the existing methods. For illustration, the new test was applied to analyze the forecastability of stock returns using technical indicators employed by White.     

国际权力基础与伊拉克战争

本文考察国际权力在不同历史时期的基础及其变化,并提出,各国围绕国际权力竞争的背后是各国围绕国际权力基础的竞争,国际权力基础随着时代不断发生变迁。作为国际政治的一个重要变量,国际权力基础反映出国际政治单位之间所享有的国际权力差异。自威斯特伐利亚条约以来,国际社会见证了数次国际权力基础变化。在第二次世界大战以前,国际权力的基础是常规武器水平;冷战期间核武器成为了新的基础;冷战结束后,各国之间的竞争围绕着综合国力展开;伊拉克战争爆发以后,国际权力基础又变迁为国家独立行动能力。     

“正能量”：科学术语中的一个“高能”热词基于认知语义的语域渗透理据分析

“正能量”是科学术语中的一个“高能”热词。其流行速度快，流行时间较长，使用域广，尤其频见于各类评论篇章。“正能量”的语义（尤指联想意义）颇丰，在反映义中，其基本义较为抽象，附加义较为显豁。其中“正”兼具基本义和附加义。“正能量”的认知语义是其成为一个高能热词的重要基础。“正能量”作为科学术语这一社会方言的某些底层遗留，有较强的句法功能，可做多种句法成分；它还具有颇强的心理现实性，这些是“正能量”得以流行和继续“走红”的重要理据。鉴于“正能量”的流行，可以预测：科技领域的某些“高能”语词还会渗透传播到社会生活领域中来。     

The Performance of Panel Unit Root and Stationarity Tests: Results from a Large Scale Simulation Study

This paper presents results on the size and power of first generation panel unit root and stationarity tests obtained from a large scale simulation study. The tests developed in the following papers are included: Levin et al. (2002), Harris and Tzavalis (1999), Breitung (2000), Im et al. (1997, 2003), Maddala and Wu (1999), Hadri (2000), and Hadri and Larsson (2005). Our simulation set-up is designed to address inter alia the following issues. First, we assess the performance as a function of the time and the cross-section dimensions. Second, we analyze the impact of serial correlation introduced by positive MA roots, known to have detrimental impact on time series unit root tests, on the performance. Third, we investigate the power of the panel unit root tests (and the size of the stationarity tests) for a variety of first order autoregressive coefficients. Fourth, we consider both of the two usual specifications of deterministic variables in the unit root literature.