Nonparametric models and their estimation

Summary Nonparametric models have become more and more popular over the last two decades. One reason for their popularity is software availability, which easily allows to fit smooth but otherwise unspecified functions to data. A benefit of the models is that the functional shape of a regression function is not prespecified in advance, but determined by the data. Clearly this allows for more insight which can be interpreted on a substance matter level. This paper gives an overview of available fitting routines, commonly called smoothing procedures. Moreover, a number of extensions to classical scatterplot smoothing are discussed, with examples supporting the advantages of the routines.     

Inhabitants' and Experts' Assessments of Environmental Quality for Urban Sustainability

In the context of sustainable urban development, we discuss the assessment of residential environmental quality and the importance of considering inhabitants' perceptions of natural resources in urban areas. Two series of studies, conducted in Guildford (United Kingdom) and in Rome (Italy), addressed the correspondence, or contrast, between inhabitants' and experts' assessment of urban quality concerning two crucial natural resources: air quality and biodiversity. The Guildford study emphasized the accuracy of the assessment of urban air quality by experts and the public. The Rome study focused on the evaluative criteria employed by scientists and the public in assessing the quality of urban green spaces. The results from both studies shed more, albeit complex, light on the simple conventional wisdom about public versus expert understanding and assessment of environmental quality. Study implications are discussed for the support of programs, methods, and tools for urban development, particularly with regard to effective communication and better structuring of residents' participation in urban environmental decision making.     

英汉文化趋同与语言文化差异

文章从文化与语言两方面论述了中西文化的趋同现象,在文化趋同的过程中语言文化差异必然存在.不同的文化在趋同中发展,在差异中共存.     

大学生心理健康与体育锻炼

文章通过对大学生心理现状和影响因素的分析,结合对体育锻炼功能的探讨,得出体育锻炼对大学生心理健康有积极作用的结论.     

Determinants of short-term value creation for the bidder: evidence from France

This paper analyses bidder short-term returns of 58 takeover bids that occur between 1997 and 2005 on the French market. Furthermore, the determinants of this performance are examined to improve understanding of the sources of value creation or destruction arising from M&A. This study reports that M&A are typically friendly, horizontal transaction, and relate to the entire target capital. The event study methodology is used to estimate bidder value creation. Three findings are shown in this study. First, we find strong evidence that the announcement of a takeover bid generates significant, high returns for the bidder with prebid blockholder position in the target (toehold) versus the bidder without toehold. In this case, there is a strong presumption that the synergies’ motive is the prime reason for the offer. Second, these results show that bidders with low potential growth positively influence share price around the bid announcement. In addition, the growth profile of the target is associated with value creation for the bidder.     

Shareholder activism among portfolio managers: rational decisions or 15 minutes of fame?

This paper investigates shareholder activism by observing Swedish portfolio managers’ behavior at firms’ annual general meetings. Institutional shareholders’ voting behavior and tendencies for raising opinions at the general meetings are related to firm characteristics, suggested by both agency theory and institutional perspectives. The results show that institutional shareholders are more likely to be active in large firms, which appear a lot in media, and have a large proportion of institutional ownership. Portfolio managers appear not to consider bad firm performance as a reason for targeting firms. Instead, managers’ behavior is consistent with the institutional notion that they benefit from the activism themselves, without trying to improve target firms’ performance. In view of this notion, it is rational for managers to be active in large firms, with large media coverage, achieving their 15 minutes of fame at the general meetings.     

An improved time-space lower bound for tautologies

We show that for all reals c and d such that c ² d<4 there exists a positive real e such that tautologies of length n cannot be decided by both a nondeterministic algorithm that runs in time n ^c , and a nondeterministic algorithm that runs in time n ^d and space n ^e . In particular, for every \(d<\sqrt[3]{4}\) there exists a positive e such that tautologies cannot be decided by a nondeterministic algorithm that runs in time n ^d and space n ^e .