广义Smoluchovski方程的定态解

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Determinants of mHealth success: An empirical investigation of the user perspective

Mobile health (mHealth) applications have become an important tool to support public health, especially in times of increased health awareness in the midst of the COVID-19 pandemic. However, there is still uncertainty about what factors determine successful mHealth services from the users’ perspective. Based on the results of a systematic literature review, a qualitative content analysis of available apps and semi-structured user and expert interviews, we derive a structural model with antecedents on user attitudes towards mHealth and user satisfaction with the mHealth application. These variables determine users’ intention to continue using the application and their intention to recommend it to others. For verification, we tested the model with a sample of 249 German mHealth users from the “MyFitnessPal” community using structural equation modelling and found that all derived path relations have significant coefficients.     

Short-term motivation trajectories: A parallel process model of expectancy-value

Motivation plays a critical role in human behavior and is particularly important during college, where a single class can make or break an academic career. The longitudinal research on expectancies for success and utility value primarily focuses on prediction or change over many years, rather than change over a short period of time. However, a single class in college can often be the difference between getting a degree or not. To better understand how motivation progresses in the short-term, we examined changes in expectancy and utility value simultaneously during a single college class. Both constructs declined during the class and showed significant variability across individuals. In addition, change in expectancy was strongly correlated with change in utility value, and the expectancy slope estimates were significant predictors of continuing interest. We discuss the need for a better understanding of short-term dynamic relationships between expectancies, utility value, and outcomes.     

Evaluation of a new equation for estimating low-density lipoprotein cholesterol through the comparison with various recommended methods

IntroductionThe accurate estimation of low-density lipoprotein cholesterol (LDL) is crucial for management of patients at risk of cardiovascular events due to dyslipidemia. The LDL is typically calculated using the Friedewald equation and/or direct homogeneous assays. However, both methods have their own limitations, so other equations have been proposed, including a new equation developed by Sampson. The aim of this study was to evaluate Sampson equation by comparing with the Friedewald and Martin-Hopkins equations, and with a direct LDL method.Materials and methodsResults of standard lipid profile (total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL) and triglycerides (TG)) were obtained from two anonymized data sets collected at two laboratories, using assays from different manufacturers (Beckman Coulter and Roche Diagnostics). The second data set also included LDL results from a direct assay (Roche Diagnostics). Passing-Bablok and Bland-Altman analysis for method comparison was performed.ResultsA total of 64,345 and 37,783 results for CHOL, HDL and TG were used, including 3116 results from the direct LDL assay. The Sampson and Friedewald equations provided similar LDL results (difference ≤ 0.06 mmol/L, on average) at TG ≤ 2.0 mmol/L. At TG between 2.0 and 4.5 mmol/L, the Sampson-calculated LDL showed a constant bias (- 0.18 mmol/L) when compared with the Martin-Hopkins equation. Similarly, at TG between 4.5 and 9.0 mmol/L, the Sampson equation showed a negative bias when compared with the direct assay, which was proportional (- 16%) to the LDL concentration.ConclusionsThe Sampson equation may represent a cost-efficient alternative for calculating LDL in clinical laboratories.     

Science teachers' conceptions of teaching and learning,ICT efficacy,ICT professional development and ICT practices enacted in their classrooms

This study assessed several precursors that might be connected to Information and Communication Technology (ICT) practices enacted in classrooms, namely, science teachers' conception of traditional versus constructivist teaching and learning, their sense of efficacy, ICT efficacy, and ICT professional development. Data were gathered from 303 science teachers. According to the results, constructivist conceptions exerted moderate effects on the teachers' sense of efficacy constructs, which in turn increased their ICT efficacy. Additional results pointed to the positive mediation role of teachers' ICT professional development in linking their ICT efficacy to ICT use for constructivist activities in their science classroom.     

Humanoid robots in higher education: Evaluating the acceptance of Pepper in the context of an academic writing course using the UTAUT

This study investigates the acceptance of social robots by higher education students in the social sciences. Pepper, a humanoid social robot from SoftBank Robotics, provided a sample of its capabilities during a first semester, large-scale, university course, “Introduction to academic writing.”From this course, 462 freshmen participated in our survey. The unified theory of acceptance and use of technology (UTAUT) acts as the conceptual framework, and partial least squares structural equation modelling (PLS-SEM) as the method for data analysis. The four perceived characteristics—trustworthiness, adaptiveness, social presence and appearance—all predict the intention to use the robot for learning purposes; anxiety regarding making mistakes in handling the robot and about privacy issues are not significant predictors. An importance-performance map analysis indicated adaptiveness as the robot’s most important characteristic for predicting student behavioural intention. Overall, however, the study shows that students do not have the intention to rely on social robots for learning purposes at the current level of state-of-the-art technology: behavioural intention reaches only 36.6% of the theoretical maximum.     

柳州市拉达水库溃坝洪水分析

柳州市拉达水库属均质土坝.本文针对拉达水库最不利工况下发生溃坝,分析拉达水库对下游的影响,为当地政府和有关单位采取防汛抢险措施,最大限度地防止及减少溃坝洪水对下游造成危害提供参考.     

一维固结微分方程及固结度的解析计算

用标准的数学物理方法详细推导一维渗流固结微分方程的傅里叶级数解,并用Mathematica绘制了压力分布的三维图,直观地展示了渗流固结过程中压力随深度和时间变化的物理规律.讨论了固结度实用公式的理论依据.结果表明:不同的边界条件决定了不同的物理进程;当t=0时,固结微分方程的级数解不适用于排水面;固结度两个实用公式的最佳转换点是Ut=0.5,而不是Ut=0.6.     

一类2×2块矩阵的特征值与特征向量分布

特征值问题在数学与工程应用中有着重要的现实意义。着重研究一类特殊的对称不定2×2块矩阵的特征值问题,充分利用其结构的特殊性,结合奇异值分解,推导出这类矩阵特征值与特征向量分布。     

基于El-Nabulsi动力学模型的Birkhoff力学

El-Nabulsi在研究非保守系统的动力学建模时,提出了三种类分数阶变分方法,即：基于Riemann-Liouville分数阶积分的变分问题,基于按指数律拓展的分数阶积分的变分问题和基于按周期函数律拓展的分数阶积分的变分问题。将上述三种El-Nabulsi动力学模型拓展到Birkhoff系统,建立了El-Nabulsi-Pfaff变分问题,导出了El-Nabulsi-Pfaff-Birkhoff-d’Alembert原理和El-Nabulsi-Birkhoff方程。文末,举例说明结果的应用。