Risk Patterns and Correlated Brain Activities. Multidimensional Statistical Analysis of fMRI Data in Economic Decision Making Study

Decision making usually involves uncertainty and risk. Understanding which parts of the human brain are activated during decisions under risk and which neural processes underly (risky) investment decisions are important goals in neuroeconomics. Here, we analyze functional magnetic resonance imaging (fMRI) data on 17 subjects who were exposed to an investment decision task from Mohr, Biele, Krugel, Li, and Heekeren (in NeuroImage 49, 2556–2563, 2010b). We obtain a time series of three-dimensional images of the blood-oxygen-level dependent (BOLD) fMRI signals. We apply a panel version of the dynamic semiparametric factor model (DSFM) presented in Park, Mammen, Wolfgang, and Borak (in Journal of the American Statistical Association 104(485), 284–298, 2009) and identify task-related activations in space and dynamics in time. With the panel DSFM (PDSFM) we can capture the dynamic behavior of the specific brain regions common for all subjects and represent the high-dimensional time-series data in easily interpretable low-dimensional dynamic factors without large loss of variability. Further, we classify the risk attitudes of all subjects based on the estimated low-dimensional time series. Our classification analysis successfully confirms the estimated risk attitudes derived directly from subjects’ decision behavior.     

Minority Representation in Special Education: 5-Year Trends

The disproportionate representation of minority students in special education has been a concern for decades. The Individuals with Disabilities Education Act mandates states to have policies and procedures in place to prevent inappropriate over identification or disproportionate representation by race and ethnicity of students with disabilities. The purpose of this study was to investigate the current status of minority representation in special education given the mandate and related efforts to reduce overrepresentation and to identify trends for the 5-year period from 2004 to 2008. Growth models were used to analyze trends in national data collected from the 50 states and the District of Columbia for these 5 years. Findings indicate some improvements from 10 years ago, especially noteworthy are a significant decrease in the number of African American students and a moderate decrease in the number of Hispanic students categorized as having intellectual disabilities. However, during the same period, the number of Hispanic students in learning disabilities increased. Otherwise, the trend of racial/ethnic representation in special education remains the same as it was a decade ago.     

Deformation behaviour and 6H-LPSO structure formation at nanoindentation in lamellar high Nb containing TiAl alloy

Microstructure and deformation mechanisms at a nanoindentation in the lamellar colony of high Nb containing TiAl alloy have been studied using the focused ion beam and the transmission electron microscopy. Considerable deformation twins are observed around the nanoindentation, and a strain gradient is generated. A continuous change in the bending angle of the lamellar structure can be derived, and a strain-induced grain refinement process is observed as various active deformations split the γ grains into subgrains. In addition to all possible deformation mechanisms (ordinary dislocation, super-dislocation and deformation twining) activated due to the heavy plastic deformation, a 6-layer hexagonal (6H) long-period stacking ordered structure is identified for the first time near the contact zone and is thought to be closely related to the glide of partial dislocations.     

创造性人格与员工创造力:一个被调节的中介模型研究

本文基于动机行动和成就动机理论,构建一个被调节的中介模型以检验创造性人格对员工创造力产生的作用机理。以251套来自主管-下属配对的问卷数据为样本,实证分析结果表明:创造性人格可预测员工创造力产生,学习目标导向与绩效证明目标导向在两者之间起部分中介作用;内在动机能够强化个体目标导向对创造力的作用,并显著正向调节创造性人格对员工创造力的间接效应。最后,论文讨论了研究发现对员工创造力产生的理论和实践意义。     

Cross-level moderating effects of Conscientiousness on within-person relationships of self-efficacy to effort allocation

Studies examining within-person level self-efficacy effects on effort allocation have produced mixed results, ranging from positive, to null, to negative. Drawing on individual differences literature, we propose that the within-person relationship between self-efficacy and effort allocation depends on Conscientiousness, a personality trait reflecting the will to achieve and capacity to self-discipline. Individuals with higher levels of Conscientiousness will respond to lower self-efficacy with increased effort, resulting in an inverse relationship between self-efficacy and effort expenditure. In contrast, individuals with lower levels of Conscientiousness will need higher self-efficacy to stay task focused and sustain effort allocation, leading to a positive effect of self-efficacy on effort expenditure. Findings from a 3-week daily diary study generally support the hypothesized moderating effects of Conscientiousness. Theoretical and practical implications are discussed.     

Formation of profuse <c+a> dislocations in deformed calcium-containing magnesium alloys

We report that <c+a> pyramidal slipping could be more easily activated in textured Mg–Ca alloys with increasing Ca contents dissolved in α-Mg matrix under tensile deformation, and it is proposed that the decreased stacking fault energy plays the critical rule. In contrast, only twins and <a> basal dislocations are observed in the compressed samples. The results would provide insight into understanding of the deformation mechanism and designing more ductile Mg alloys.