Puberty Predicts Approach But Not Avoidance on the Iowa Gambling Task in a Multinational Sample

According to the dual systems model of adolescent risk taking, sensation seeking and impulse control follow different developmental trajectories across adolescence and are governed by two different brain systems. The authors tested whether different underlying processes also drive age differences in reward approach and cost avoidance. Using a modified Iowa Gambling Task in a multinational, cross‐sectional sample of 3,234 adolescents (ages 9–17; M = 12.87, SD = 2.36), pubertal maturation, but not age, predicted reward approach, mediated through higher sensation seeking. In contrast, age, but not pubertal maturation, predicted increased cost avoidance, mediated through greater impulse control. These findings add to evidence that adolescent behavior is best understood as the product of two interacting, but independently developing, brain systems.     

Latent class analysis of non-formal learners’ self-directed learning patterns in open educational resource repositories

Open educational resources (OERs) are increasingly adopted in non-formal education contexts. However, little research has been conducted to investigate the self-directed learning patterns of non-formal learners using OERs. A lack of knowledge about non-formal learners precludes discussions on how to support their self-regulated learning in open learning environments. We explored the self-directed learning patterns of 1892 non-formal online learners who were using OER repositories. In addition, we examined whether differences existed in future intentions to use OERs between learners with different learning patterns. Four latent classes were identified, and learners’ age was found to affect class membership. We also found that non-formal learners’ use of self-directed learning strategies predicted their future intentions to use OERs. This study advanced our understanding of the subpopulations of non-formal learners using OERs. Future research will benefit from the findings related to designing OER environments that can accommodate diverse self-directed learners.     

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.     

Roles of alternative and self-oriented perspectives in the context of the continued use of social network sites

Individuals with a positive evaluation of a target system are likely to continue using the system, and this sustained use is likely to result in continued use. This target-oriented perspective has served as a major conceptual framework for understanding users’ behaviors in online contexts. The primary objective of this paper is to address two additional perspectives—alternative- and self-oriented perspectives—for a firmer understanding of continued use in the context of social network sites (SNS). A research model is built by employing regret and self-image congruity to represent these two perspectives. The model also examines the condition under which habits are formed and how this automatic mechanism influences the dynamics of the nomological network between intentions and behaviors. The analysis results of two rounds of surveys for capturing the actual link between intentions and behaviors indicate that regret and self-image congruity can play crucial roles in post-adoption phenomena in the context of SNS.     

Korean elementary school students’ English learning demotivation: a comparative survey study

This study explores Korean elementary school students’ decreased motivation for English learning by analyzing the questionnaire data obtained from 6,301 students in a large city in South Korea. The students’ school grades and their prior experience in private institutes were considered as the major factors behind the decrease in their motivation. There was a statistically significant and consistent decrease in the students’ satisfaction with their English learning experience; expectation of ultimate success in English; and intrinsic/extrinsic motivation and integrative/instrumental motivation. Prior experience in attending private institutes had a substantial impact on the students’ motivation. Those who attended private institutes (hakwons) exhibited higher levels of instrumental and intrinsic motivation. However, in terms of other motivational constructs of integrative and extrinsic (parental, academic) motivation, private instruction had a negligible or negative impact. By comparing the results with those of Lamb (2007), the present study proposes that Korean students should be made to internalize the beneficial role played by English so that their English learning motivation can be maintained.     

Investigating Stage-Sequential Growth Mixture Models with Multiphase Longitudinal Data

This article investigates three types of stage-sequential growth mixture models in the structural equation modeling framework for the analysis of multiple-phase longitudinal data. These models can be important tools for situations in which a single-phase growth mixture model produces distorted results and can allow researchers to better understand population heterogeneity and growth over multiple phases. Through theoretical and empirical comparisons of the models, the authors discuss strategies with respect to model selection and interpreting outcomes. The unique attributes of each approach are illustrated using ecological momentary assessment data from a tobacco cessation study. Transitional discrepancy between phases as well as growth factors are examined to see whether they can give us useful information related to a distal outcome, abstinence at 6 months postquit. It is argued that these statistical models are powerful and flexible tools for the analysis of complex and detailed longitudinal data.     

On the construction of cryptographically strong Boolean functions with desirable trade-off

INTRODUCTION A variety of desirable criteria for functions have been identified: balancedness, local and global ava-lanche characteristics, high nonlinearity, etc. These properties are also very important for cryptographic purpose. Obtaining optimal tradeoffs among so many properties is hard. If we take into account more crite-ria, it is more difficult to generate Boolean functions satisfying those properties purely by constructive algebraic methods. How to construct Boolean func-tions …     

Teachers who abuse: the impact on school communities

This paper addresses issues that may arise of a teacher or school employee is abusing pupils within the school community. Interviews were conducted with a number of respondents who had experienced situations of abuse within the school context. The incidents used, as case examples, all concern sexual abuse, although the framework developed could be used to examine different types of abuse. The paper concludes that changes in legislation and guidelines can improve practice, but that less tangible issues will continue to be involved when dealing with abuse, and that raising awareness of the issues is a key factor.     

Differential Item Functioning in Biodata: Opportunity Access as an Explanation of Gender- and Race-Related DIF

Investigations of differential item functioning (DIF) have been conducted mostly on ability tests and have found little evidence of easily interpretable differences across various demographic subgroups. In this study, we examined the degree to which DIF in biographical data items referencing academically relevant background, experiences, and interests was related to differences in judgments about access to these experiences by members of different gender and race subgroups. DIF in the location parameter was significantly related (r = –.51, p < .01) to gender differences in perceived accessibility to experience. No significant relationships with accessibility were observed for DIF in the slope parameter across gender groups or for the slope and location parameters associated with DIF across Black and White groups. Practical implications for use of biodata and theoretical implications for DIF research are discussed.