Comparisons of Three Empirical Methods for Partial Factorial Invariance: Forward,Backward, and Factor-Ratio Tests

When factorial invariance is violated, a possible first step in locating the source of violation(s) might be to pursue partial factorial invariance (PFI). Two commonly used methods for PFI are sequential use of the modification index (backward MI method) and the factor-ratio test. In this study, we propose a simple forward method using the confidence interval (forward CI method). We compare the performances of the aforementioned 3 methods under various simulated PFI conditions. Results indicate that the forward CI method using 99% CIs has the highest perfect recovery rates and the lowest Type I error rates. A performance that is competitive with this is that produced by the backward method with the more conservative criterion (MI = 6.635). Consistently delivering the poorest performance, regardless of the chosen confidence level, was the factor-ratio test. Also discussed are the work’s contribution, implications, and limitations.     

韩国消费者对中国冰箱选择的研究

本研究以首尔(Seoul)的MBA学生为对象,实证分析了中国的国家形象、中国冰箱的功能属性和品牌个性对于韩国消费者的中国冰箱选择具有什么影响。结果表明,韩国消费者考虑购买中国冰箱时,除了国家形象、功能属性以外还受到品牌个性因素的影响。本研究指出了进入韩国的中国企业应开发与国家形象有关的、有个性的品牌产品,即品牌个性会提高品牌知名度,增加企业信赖度,从而成为韩国市场上更受欢迎的品牌,也将为有效的品牌市场导向提供产品差别化,这样可以使中国企业在竞争中获得优势。     

Low-cost,disposable microfluidics device for blood plasma extraction using continuously alternating paramagnetic and diamagnetic capture modes

Blood plasma contains biomarkers and substances that indicate the physiological state of an organism, and it can be used to diagnose various diseases or body condition. To improve the accuracy of diagnostic test, it is required to obtain the high purity of blood plasma. This paper presents a low-cost, disposable microfluidics device for blood plasma extraction using magnetophoretic behaviors of blood cells. This device uses alternating magnetophoretic capture modes to trap and separate paramagnetic and diamagnetic cells away from blood plasma. The device system is composed of two parts, a disposable microfluidics chip and a non-disposable (reusable) magnetic field source. Such modularized device helps the structure of the disposable part dramatically simplified, which is beneficial for low-cost mass production. A series of numerical simulation and parametric study have been performed to describe the mechanism of blood cell separation in the microchannel, and the results are discussed. Furthermore, experimental feasibility test has been carried out in order to demonstrate the blood plasma extraction process of the proposed device. In this experiment, pure blood plasma has been successfully extracted with yield of 21.933% from 75 μl 1:10 dilution of deoxygenated blood.     

The impact of conflicting goals on mathematical teaching decisions

This paper describes part of an international project considering graphical construction of antiderivative functions in the secondary mathematics classroom. We use Schoenfeld’s resources, orientations, and goals (ROGs) framework to analyse the decisions made by a teacher, Adam, during a lesson on graphical antiderivatives. We present details of Adam’s ROG and see how this is related to resolution of the conflict between his competing goals and the decisions he makes. The results suggest that a beneficial professional development strategy might be to assist teachers to become more aware of their ROG and its influence on in-the-moment classroom decisions.     

Density-dependent separation of encapsulated cells in a microfluidic channel by using a standing surface acoustic wave

This study presents a method for density-based separation of monodisperse encapsulated cells using a standing surface acoustic wave (SSAW) in a microchannel. Even though monodisperse polymer beads can be generated by the state-of-the-art technology in microfluidics, the quantity of encapsulated cells cannot be controlled precisely. In the present study, mono-disperse alginate beads in a laminar flow can be separated based on their density using acoustophoresis. A mixture of beads of equal sizes but dissimilar densities was hydrodynamically focused at the entrance and then actively driven toward the sidewalls by a SSAW. The lateral displacement of a bead is proportional to the density of the bead, i.e., the number of encapsulated cells in an alginate bead. Under optimized conditions, the recovery rate of a target bead group (large-cell-quantity alginate beads) reached up to 97% at a rate of 2300 beads per minute. A cell viability test also confirmed that the encapsulated cells were hardly damaged by the acoustic force. Moreover, cell-encapsulating beads that were cultured for 1 day were separated in a similar manner. In conclusion, this study demonstrated that a SSAW can successfully separate monodisperse particles by their density. With the present technique for separating cell-encapsulating beads, the current cell engineering technology can be significantly advanced.     

When tensions between ideology and practice become personal: Unpacking mentorship in early childhood teacher education

University-based teacher education programs are criticized for being too theoretical, disconnected from the everyday realities of schools. To bridge this gap, teacher education programs give students year-long field experiences under the joint tutelage of mentor teachers and university faculty. However, this assumes that mentor teachers will not only be exemplary teachers, but skilled mentors as well. This article explores the tensions between the theoretical and practical work of teaching within mentoring relationships, specifically in spaces where teacher agency is limited by political, social, and cultural factors. The sociocultural, language approaches in many teacher education programs are seen as idealistic when pushed up against skills-based language approaches, advocated in classrooms. Using qualitative methods, this project follows three mentor/mentee pairs as they negotiate their relationships in an urban area in the Southwest United States. While all three pre-service teachers strongly believed that learning was a social practice, constructed through child inquiry and play, they struggled to maintain their ideologies and beliefs during their field experience. Pre-service teachers held firmly to their beliefs about teaching and learning, but holding onto these beliefs were wrought with personal and philosophical tensions. Pre-service teachers found limited agency in their practice and little support in implementing their own practices. Most importantly, unequal power dynamics and communication issues were obstacles towards mutually beneficial mentorship. Thus, preservice programs must address the importance of developing and cultivating the mentor/mentee relationship—a relationship that is pivotal in the construction of preservice teachers’ identities and practices.     

Infusing Culturally Responsive Science Curriculum into Early Childhood Teacher Preparation

Research in Science Education - Previous research studies in early childhood teacher education have indicated that teacher candidates are not adequately prepared to demonstrate the knowledge and...     

Specification Search for Identifying the Correct Mean Trajectory in Polynomial Latent Growth Models

This study investigated the optimal strategy for model specification search under the latent growth modeling (LGM) framework, specifically on searching for the correct polynomial mean or average growth model when there is no a priori hypothesized model in the absence of theory. In this simulation study, the effectiveness of different starting models on the search of the true mean growth model was investigated in terms of the mean and within-subject variance-covariance (V-C) structure model. The results showed that specifying the most complex (i.e., unstructured) within-subject V-C structure with the use of LRT, ΔAIC, and ΔBIC achieved the highest recovery rate (>85%) of the true mean trajectory. Implications of the findings and limitations are discussed.     

Policy efforts to increase women faculty in Korea: reactions and changes at universities

Since 2001, the issue of the low ratio of women faculty in universities has been prominent in Korea because of its negative impact on female students and gender equality at the university level that has affected human resource development and utilization at the national level. To address this issue, the Korean government developed and executed an education policy, the Policy on Women Faculty Increase (PWFI) from 2004 to 2006. This paper investigated reactions to the PWFI and changes made as a result of the policy in the conservative Korean higher education context. We found that although the PWFI has particularly contributed to increasing the representativeness of women faculty in areas in which women faculty used to be rare, overall the PWFI has not made significant improvements in most participating universities due to the lack of internal motives and drivers and effective systems to support the policy. Recommendations for improvements in the policy are offered.