Numerical simulation on the opto-electro-kinetic patterning for rapid concentration of particles in a microchannel

This paper presents a mathematical model for laser-induced rapid electro-kinetic patterning (REP) to elucidate the mechanism for concentrating particles in a microchannel non-destructively and non-invasively. COMSOL^®(v4.2a) multiphysics software was used to examine the effect of a variety of parameters on the focusing performance of the REP. A mathematical model of the REP was developed based on the AC electrothermal flow (ACET) equations, the dielectrophoresis (DEP) equation, the energy balance equation, the Navier-Stokes equation, and the concentration-distribution equation. The medium was assumed to be a diluted solute, and different electric potentials and laser illumination were applied to the desired place. Gold (Au) electrodes were used at the top and bottom of a microchannel. For model validation, the simulation results were compared with the experimental data. The results revealed the formation of a toroidal microvortex via the ACET effect, which was generated due to laser illumination and joule-heating in the area of interest. In addition, under some conditions, such as the frequency of AC, the DEP velocity, and the particle size, the ACET force enhances and compresses resulting in the concentration of particles. The conditions of the DEP velocity and the ACET velocity are presented in detail with a comparison of the experimental results.     

What Motivates Parents to Mediate Children’s Use of Smartphones? An Application of the Theory of Planned Behavior

Applying the Theory of Planned Behavior (TPB), this study examines parents’ attitudes, social norms, self-efficacy, and intentions regarding parental mediation of children’s smartphone use. A survey conducted with parents of young smartphone users aged 10–17 shows that parents tend to perceive discussion-based active mediation to be more desirable, as compared to rule-making restrictive mediation. Findings also indicate that the extent to which parents believe that they have control over their parental mediation practices plays an important role in forming positive intentions to practice parental mediation, regardless of the mediation domain.     

An unexpected particle oscillation for electrophoresis in viscoelastic fluids through a microchannel constriction

Electrophoresis plays an important role in many applications, which, however, has so far been extensively studied in Newtonian fluids only. This work presents the first experimental investigation of particle electrophoresis in viscoelastic polyethylene oxide (PEO) solutions through a microchannel constriction under pure DC electric fields. An oscillatory particle motion is observed in the constriction region, which is distinctly different from the particle behavior in a polymer-free Newtonian fluid. This stream-wise particle oscillation continues until a sufficient number of particles form a chain to pass through the constriction completely. It is speculated that such an unexpected particle oscillating phenomenon is a consequence of the competition between electrokinetic force and viscoelastic force induced in the constriction. The electric field magnitude, particle size, and PEO concentration are all found to positively affect this viscoelasticity-related particle oscillation due to their respective influences on the two forces.     

Opinion Versus Knowledge: The Influence of Testimony Format on Children’s Judgments in Morally Relevant Contexts

Research Findings: To test children’s use of testimony of others, 3 – 9 years (N = 227) made judgments about a potential peer transgression in which the intentions of the protagonist were ambiguous, after hearing two different forms of testimony. The 2 forms of testimony were (a) opposing opinion-based testimony from an adult authority versus a peer consensus group and (b) knowledge-based testimony (eyewitness testimony) that was counter to the participants’ initial judgments. Findings revealed that when testimony was presented in an opinion-based format, children were likely to side with the opinion that reflected their own interpretation of the peer encounter, regardless of whether the opinion came from a peer consensus or an adult authority. However, when knowledge-based testimony was introduced in support of the opposite of children’s initial interpretation of the ambiguous peer encounter, children most often changed their initial judgment to align with the new testimony. That is, children used knowledge-based testimony but not opinion-based testimony to evaluate a potential transgression. Practice or Policy: These findings demonstrate that the way in which testimony is delivered to children has a direct influence on their decision making about peer interactions and has relevance for teacher–student discourse in the classroom.     

Supporting School Readiness Through Librarian-Child Interactions in Public Library Storytimes: An Analysis of Assessment Scores and Influential Factors

Early Childhood Education Journal - A recent trend in public libraries′ children’s services emphasizes the role of promoting school readiness. In order to gain a deeper understanding of...     

SNS use by the Korean government: a case of Me2Day

This study examines the debates and discussions surrounding the Korean government's Me2Day, the largest social networking and microblogging site in the country used by 26 government bureaus, including the Blue House. Me2Day users post messages composed of up to 150 characters and establish links with other users through multimedia-based information and knowledge obtained from their browsers, desktop computers, e-mail messages, and mobile phones. This study provides a better understanding of the characteristics and structures of cyberspace communication between the Korean government and citizens. The results indicate that although each bureau had different goals in terms of using Me2Day, users were more likely to use the service if their bureau actively posted messages or responded to user comments. Users tended to have critical attitudes toward the Korean government when they were allowed to freely post messages and share information.     

声音反馈对高尔夫挥杆训练效果的生物力学影响

目的:从生物力学角度探究声音反馈训练(teaching with acoustical guidance,TAGteachTM)和传统训练方法对高尔夫初学者击球效果和挥杆动作的影响。方法:21名无高尔夫训练基础的大学生受试者随机分为声音反馈训练组(clicker training group,CG,n=11)和传统训练组(traditional training group,TG,n=10),由一名韩国职业高尔夫教练员进行5周的高尔夫挥杆动作教学训练,使用7号铁杆。训练后,对受试进行挥杆动作生物力学测试,对比两组受试者的击球效果和挥杆动作。结果:5周声音反馈训练后,CG杆速、球速、杆面角度、击球距离等击球表现指标显著优于TG(P<0.01)。挥杆动作方面,CG从上杆阶段到随挥初期挥杆时间显著小于TG(P<0.05),骨盆转动速度显著大于TG(P<0.05);CG骨盆转动角度和COM-COP倾角的标准化角加速度变化率显著小于TG(P<0.05)。结论:声音反馈是一种有效的训练辅助手段,可提升高尔夫初学者的挥杆练习效果。     

Successful recanalization of chronic total occlusion of the superior mesenteric artery by transradial approach

It is a challenge to confirm chronic mesenteric ischemia (CMI) as a cause of gastrointestinal (Gl) symptoms such as postprandial epigastric bloating,anorexia,and debilitating weight loss.Endovascular intervention for CMI has been gaining popularity because of the high morbidity associated with surgical revascularization.However,in EVI for superior mesenteric artery (SMA) occlusion,the transfemoral approach is limited by difficulty in coaxial alignment of the guiding catheter,which leads to insufficient back-up support.Herein,we report on a 58-year-old male patient with chronic total occlusion of the SMA,which was successfully revascularized by endovascular intervention via the left radial artery.Transradial endovascutar therapy may be another treatment option for the treatment of CMI.     

Academic socialization of doctoral students through feedback networks: a qualitative understanding of the graduate feedback landscape

ABSTRACT

Scholars focus on the social nature of academic writing to refine an understanding of feedback interactions in higher education. However, studies on the various sources of feedback – feedback networks – have been scarce, particularly during the initial years of doctoral education. Using a qualitative case study approach, multiple sources of feedback for four students in one doctoral program in the United States were identified in line with broader trends focusing on feedback as a social practice. Informed by the academic socialization framework [Duff, Patricia A. 2012. “Second Language Socialization.” In Handbook of Language Socialization, edited by Alessandro Duranti, Elinor Ochs, and Bambi B. Schieffelin, 564–586. Malden: Wiley-Blackwell], this study aims (1) to navigate the landscape of graduate feedback, including interactions beyond class as well as oral and written feedback, and (2) to elucidate the socialization process. Findings suggest that academic writing development is defined as how feedback is situated within disciplinary, academic communities of interaction. This article describes how the larger network of feedback creates the types of interaction that characterizes the community.     

Mapping beliefs about teaching to patterns of instruction within science,technology, engineering,and mathematics

In this paper, we identify beliefs about teaching and patterns of instruction valued and emphasized by science, technology, engineering, and mathematics faculty in higher education in the USA. Drawing on the notion that effective teaching is student-centered rather than teacher-centered and must include a balance of knowledge-, learner-, community-, and assessment-centered learning environments; we use qualitative interview data to explore how faculty's reported beliefs about teaching are associated with their consideration of these four types of environments. Findings indicated that although a range of beliefs about teaching emerged, most were firmly located in knowledge-centered learning environments, with little or no focus on the remaining three learning environments. Furthermore, even patterns of instruction that were heavily student-centered were situated within a knowledge-centered learning framework. We argue that for student-centered instruction to be truly successful, faculty must consider all four learning environments in crafting and facilitating the classroom environment.