Mirror or Molder? A Study of Media Coverage,Stock Prices,and Trading Volumes in Germany

This article investigates the short‐term relationship between media coverage, stock prices, and trading volumes of eight listed German companies. A content analysis of news reports about the selected companies and a secondary analysis of the daily changes in closing prices and the trading volumes of these companies were combined in a time‐series design. After ARIMA‐modeling each of them, the results suggest that media coverage rather reflects than shapes the development at stock exchanges from a short‐term perspective (2 months). There were almost no hints for a widespread media effect, that is, an impact on so many investors that it will result in a measurable change in stock prices or trading volumes. Finally, theoretical and methodological consequences for exploring widespread media effects are discussed.     

Identifying user preferences with Wrapper-based Decision Trees

Wrapper feature selection approaches are widely used to choose a small subset of relevant features from a dataset. However, Wrappers suffer from the fact that they only use a single classifier. The downside to this is that each classifier will have its own biases and will therefore select very different features. To overcome the biases of individual classifiers, we propose a new data mining method called Wrapper-based Decision Trees (WDT). The WDT method uses multiple classifiers for selecting relevant features and decision trees to visualize relationships among the selected features. We use the WDT to investigate the influences of the levels of computer experience on users’ preferences for the design of search engines. The benefit of using WDT lies within the fact that it can uncover the most accurate set of relevant features to help differentiate the preferences of users with diverse levels of computer experience. The results indicate that the users with varied levels of computer experiences have different preferences regarding the following features: the number of icons, the arrangement of search results, and the presentation of error messages. Such findings can be used to develop personalized search engines to accommodate users’ different levels of computer experience.     

Investigation of the microstructure of alkali-activated cements by neutron scattering

Significant research has been devoted to understanding and modeling the neutron scattering behavior of Portland cement pastes. The present work examines the potential of neutron scattering to noninvasively evaluate the properties of alternative cementitious materials encountered in the field. To interpret the scattering of both alkali-activated and slag-cement systems, alternative models to those typically adopted for Portland cement pastes were considered. Investigation of alkali-activated and slag-cement coupons were conducted for different sample thickness (∼0.5, 1, 2, 4, 6, 8 and 12 mm) over a wide scattering vector (Q) range (0.0005<Q>0.03 nm⁻¹ and 0.04<Q>4 nm⁻¹) on both ultra (USANS) and conventional small-angle neutron scattering (SANS) spectrometers. This wide Q range allowed determination of the fractal properties of the microstructure as well as the radius of the main scattering particle in the material. An empirical correction for multiple scattering was made based on the Dexter-Beeman equation and demonstrated that for thicker sample widths the theory correlated reasonably well. Alkali-activated fly ash was found to have the largest R value while the OPC and slag mix exhibited the largest Guinier radius. This difference was attributed to variations in the extent of multiple scattering for the samples. Successful application of this model was limited to sample thickness ≥1 mm. A combined power law-Sabine expression was also utilized to successfully model the SANS data over a Q range of 0.04-4 nm⁻¹.     

A longitudinal study of short- and long-term activity levels in male and female spontaneously hypertensive, Wistar-Kyoto, and Sprague-Dawley rats.

The pattern of locomotor activity across development was assessed in male and female spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Sprague-Dawley (SD) rats. Open field activity did not indicate hyperactivity in the SHR. Instead, the SD strain was generally more active. Strains and sexes did not differ in open-field locomotor response to drug challenges. When short-term (10-12 min) activity in different apparatuses was compared, the SD were most active in the open field, the SHR in the residential figure-eight maze, and the WKY in the running wheel. Long-term tests indicated hyperactivity in the SHR in the residential figure-eight maze and hypoactivity in the SD in the running wheels. Until such strain differences in activity are thoroughly defined, the use of the SHR as a model of attention-deficit/hyperactivity disorder is limited. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Statistical data analysis of magnetic recording noise mechanisms

Statistical data analysis using empirical eigenfunctions, known as the Karhunen-Loeve (K-L) expansion, is applied to characterize noise mechanisms in magnetic recording. Given any original data set and hence its correlation (covariance) matrix, an empirical orthogonal set of eigenfunctions can be obtained. The original data set can be expressed as an orthonormal expansion of these eigenfunctions. This feature of the K-L expansion can be used to study dominant noise profiles extracted from a large number of magnetization transition data. Two simple models of magnetization transitions are first utilized to investigate the validity of this expansion. Noises induced by transition center shifting (jitter), transition width fluctuation, amplitude modulation, and combined effects are respectively identified by the first several most important eigenfunctions in the expansion. Eigenfunction expansions of transition data obtained from experiments and numerical simulations are also obtained     

Evaluation of triple quantum-filtered 23Na NMR spectroscopy in the in situ rat liver

Expression of intermediate filaments (IFs) has been suggested to be a reliable marker for differentiating epithelial and non-epithelial tumors. Moreover, the c-erbB-2 and p53 genes are considered to be involved relatively early in the process of human carcinogenesis. In order to elucidate the origin of uterine carcinosarcomas, we analyzed IF, c-erbB-2 and p53 expression in and the ultrastructural characteristics of clones derived from a human uterine-carcinosarcoma cell line, EMTOKA. The expression of IFs and other proteins in the EMTOKA clones was identical to that in the EMTOKA cell line. It and its 7 clones all expressed cytokeratins 8, 17, 18 and 19, vimentin, epithelial membrane antigen, S-100, myoglobin, type-II collagen, alpha-smooth-muscle actin, placental alkaline phosphatase and epidermal-growth-factor receptor. The c-erbB-2 and p53 expression levels of all the cell types of the EMTOKA cell line and its clones were the same. Interestingly, an ultrastructural study showed that the EMTOKA cell line and its clones at early and late passages possessed the characteristics of epithelial cell types without either transitional forms between the epithelial and stromal components or differentiation into sarcomatous components. The results of this study lend particular support to the combination tumor hypothesis that a precursor (stem) cell gives rise both to epithelial and to mesenchymal components during the histogenesis of uterine carcinosarcoma, the epithelial component of which appears to be dominant, suggesting that the established cell lines derived from a common stem cell.     

保存回忆,保存古建筑的概念化工具--访香港中文大学建筑系教授何培斌

保存过去是可持续发展的一部分,保存古建筑,促发人们思考未来的问题.在今年七月,由香港珠海学院( Chu Hai College of Higher Education)建筑系主办的一场题为"文化传承:可持续发展及美学"的研讨会,来自香港、新加坡、台湾和内地的政府官员、专家学者及民间古迹保护人士就一系话题进行探讨:新加坡政府如何透过规划(MASTER PLAN 2003)保存其城市的独特身份?