Shear vibration of a crystal plate carrying an array of microbeams

We study shear vibration of a rotated Y-cut quartz crystal plate carrying an array of microbeams with their bottoms fixed to the top surface of the plate. The beams undergo flexural vibrations when the plate is in shear motion. The plate is modeled by the theory of anisotropic elasticity. The beams are modeled by the Euler–Bernoulli theory for beam bending. A frequency equation that determines the resonant frequencies of the structure is derived. An analytical solution on beam-induced frequency shift is obtained using a perturbation procedure. It is shown that the frequency shift may be used to measure geometric/physical properties of the beam array. A vibrating crystal plate carrying a beam array may also be considered for application as an ultrasonic brush.     

Christian Leadership and Religiosity Reexamined: The Evidence from College Student Leaders

This article assesses the impact of religiosity on Christian leadership orientations. The theoretical model is taken from the study of Shee, Ji, and Boyatt (2002), which presupposes that quest religiosity is inversely related to the structured, human resource, political, and symbolic leadership frames, while intrinsic and extrinsic religiosity are positively tied with them. The analysis is based on the 116 college student leaders in 12 Protestant colleges and universities. According to the data, the patterns of linkage between religious orientations and leadership frames lend partial support for the hypothesis. Intrinsic religiosity tends to foster structural and symbolic leadership, but quest religiosity promotes political leadership. The human resource leadership has turned out to be independent from religiosity, and extrinsic religiosity is found to have little to do with Christian leadership orientations.     

Anxiety and Depression Symptoms in Children with Asperger Syndrome Compared with Attention-Deficit/Hyperactivity Disorder and Depressive Disorder

The objective of this study was to examine (a) anxiety and depression symptoms in children with Asperger syndrome (AS) compared to children with attention-deficit/hyperactivity disorder (ADHD) and children with depressive disorder; (b) parental anxiety and depressive symptoms in the three groups; and (c) the association between the anxiety and depression symptoms of children and their parents. The emotional and behavioral problems of 56 children with AS (48 boys, 8 girls, mean age, 9.39 ± 2.01 years) were compared with 56 ADHD children and 56 depressive disorder children, matched for age and sex. Their parents’ anxiety and depression symptoms were also compared. Trait-anxiety and internalizing problems in AS children were higher than those in ADHD children and as high as those in depressive disorder children (F = 8.83, p < 0.001 and F = 8.21, p < 0.001). Parents’ anxiety and depression symptoms did not differ among the three groups, but correlations between maternal anxiety and depression and children’s emotional and behavioral problems were most prominent in the AS group. We suggest that the assessment and treatment of children with AS should involve detailed assessment, possible concomitant treatment for comorbid anxiety and depression, and parental education about the effect of parental emotional states on children.     

Model Selection with the Linear Mixed Model for Longitudinal Data

Model building or model selection with linear mixed models (LMMs) is complicated by the presence of both fixed effects and random effects. The fixed effects structure and random effects structure are codependent, so selection of one influences the other. Most presentations of LMM in psychology and education are based on a multilevel or hierarchical approach in which the variance-covariance matrix of the random effects is assumed to be positive definite with nonzero values for the variances. When the number of fixed effects and random effects is unknown, the predominant approach to model building is a step-up method in which one starts with a limited model (e.g., few fixed and random intercepts) and then additional fixed effects and random effects are added based on statistical tests. A model building approach that has received less attention in psychology and education is a top-down method. In the top-down method, the initial model has a single random intercept but is loaded with fixed effects (also known as an “overelaborate” model). Based on the overelaborate fixed effects model, the need for additional random effects is determined. There has been little if any examination of the ability of these methods to identify a true population model (i.e., identifying the model that generated the data). The purpose of this article is to examine the performance of the step-up and top-down model building approaches for exploratory longitudinal data analysis. Student achievement data sets from the Chicago longitudinal study serve as the populations in the simulations.     

A Systematic Review of Propensity Score Methods in the Social Sciences

The use of propensity scores in psychological and educational research has been steadily increasing in the last 2 to 3 years. However, there are some common misconceptions about the use of different estimation techniques and conditioning choices in the context of propensity score analysis. In addition, reporting practices for propensity score analyses often lack important details that allow other researchers to confidently judge the appropriateness of reported analyses and potentially to replicate published findings. In this article we conduct a systematic literature review of a large number of published articles in major areas of social science that used propensity scores up until the fall of 2009. We identify common errors in estimation, conditioning, and reporting of propensity score analyses and suggest possible solutions.     

Sentence Complexity and Working Memory Effects in Ambiguity Resolution

Two self-paced reading experiments using a paraphrase decision task paradigm were performed to investigate how sentence complexity contributed to the relative clause (RC) attachment preferences of speakers of different working memory capacities (WMCs). Experiment 1 (English) showed working memory effects on relative clause processing in both offline RC attachment preferences and in online reading time measures, but no effects of syntactic complexity. In Experiment 2 (Korean), syntactic complexity due to greater distance between integrating heads, as measured by the dependency locality theory (Gibson in Cognition 68:1–76, 1998), significantly increased the proportion of attachment to NP1. However, no effects of working memory were found. The difference in results between English and Korean is proposed to be due to head-directionality effects. The results of our study support the conclusion that working memory-based accounts provide a better explanation than previous language-dependent accounts for differences in RC attachment preferences. We propose that previous language dependent-accounts of cross-linguistic differences in RC processing have overlooked the interaction between individual WMC and a language’s general structure, which is a central factor in RC attachment.     

Parent Grief 1–13 Months After Death in Neonatal and Pediatric Intensive Care Units

Objective. Describe changes in mothers’ and fathers’ grief from 1 to 13 months after infant or child neonatal or pediatric intensive care unit death and identify factors related to their grief.

Methods. Mothers (n = 130) and fathers (n = 52) of 140 children (newborn–18 years) completed the Hogan Grief Reaction Checklist at 1, 3, 6, and 13 months postdeath.

Results. Grief decreased from 3 to 13 months for mothers and from 3 to 6 months for fathers. Grief was more intense for mothers of deceased adolescents and mothers whose children were declared brain dead.

Conclusion. Mothers’ and fathers’ grief intensity may not coincide, resulting in different needs during the 13 months after infant or child death.     

Kinetic study of static recrystallization in an Fe–Al–O ultra-fine-grained nanocomposite

A nearly abrupt coarsening of grains is observed in a newly developed Fe–Al–O ultra-fine-grained nanocomposite with a significant volume fraction (4%) of alumina nano-precipitates. The microstructure of the alloy was analysed in different states (as-received and annealed) by means of scanning electron microscopy, transmission electron microscopy (TEM) and hardness. The initial grain size 150–200 nm increases up to 50 μm during annealing 1000 °C/8 h and thereafter demonstrates saturation. A linear correlation between volume fraction of coarse grains and hardness was found. It was identified by TEM that alumina nano-precipitates stabilize the dislocation microstructure against recovery very effectively and the grain coarsening is due to fast growth of very few dislocation free grains. Thus, the observed grain coarsening has the attributes of static recrystallization.     

小学低年级学生自我监控与监控他人的发展研究

元认知监控包括自我监控和监控他人。本研究用两个实验分别探讨了小学低年级学生自我监控和监控他人之间的关系及其发展趋势。实验一采用100以内加减法的计算任务,来探讨小学低年级学生的自我监测和监测他人。实验二采用难度不同、分值不同的计算任务,来探讨学生的自我控制和控制他人。研究发现:第一,小学低年级学生的自我监测和监测他人都会以前期任务表现为依据,支持MPT假说。而且,自我监测和监测他人都在二年级表现出了明显的转化和提高。第二,小学低年级学生在监测他人时,逐渐由以自我信息为依据调整到以他人认知状态为依据。第三,元认知控制能力的发展落后于监测能力。二年级和三年级学生仍旧不能很合理地进行自我执行和计划他人。