Numerical modeling of DNA-chip hybridization with chaotic advection

We present numerical simulations of DNA-chip hybridization, both in the “static” and “dynamical” cases. In the static case, transport of free targets is limited by molecular diffusion; in the dynamical case, an efficient mixing is achieved by chaotic advection, with a periodic protocol using pumps in a rectangular chamber. This protocol has been shown to achieve rapid and homogeneous mixing. We suppose in our model that all free targets are identical; the chip has different spots on which the probes are fixed, also all identical, and complementary to the targets. The reaction model is an infinite sink potential of width d_h, i.e., a target is captured as soon as it comes close enough to a probe, at a distance lower than d_h. Our results prove that mixing with chaotic advection enables much more rapid hybridization than the static case. We show and explain why the potential width d_h does not play an important role in the final results, and we discuss the role of molecular diffusion. We also recover realistic reaction rates in the static case.     

Predicting Physical Activity Among Children: Investigating Interaction Effects in the Theory of Planned Behavior

ABSTRACT

Purpose: The theory of planned behavior (TPB) has been criticized for not including interactions between the variables assumed to predict behavior. This study sought to test how TPB variables interact to predict physical activity (PA) in children. Method: Four hundred thirty-eight children (M_age = 8.6 years, SD = 1.6 years) completed a TPB questionnaire and a PA questionnaire at Time 1. The PA measure was repeated 2 months later. Path analyses were performed to test the hypothesized model including interaction terms between TPB variables. Simple slopes analyses were also carried out to examine the statistically significant interaction terms. Results: Path analyses confirmed the classical hypotheses of TPB (R² for intentions = .39, R² for PA = .12) and also demonstrated only statistically significant Attitudes × Perceived Behavioral Control and Subjective Norms × Attitudes interactions (R² change for intentions = .01, p = .009). Simple slopes analyses revealed that the strength of the association between perceived behavioral control and intentions was only statistically significantly higher (t = 2.18, p = .05, d = 0.34, 95% CI [0.03, 0.65]) when attitudes were high compared with when attitudes were low. The link between attitudes and intentions was only statistically significant at a low level of subjective norms but not at a high level. Conclusion: The integration of interaction effects between TPB variables did not increase for the variance of PA explained by the model. More research appears to be necessary to explore how the TPB could be augmented to better predict PA in children.     

Extracurricular Activities,Screen Media Activity,and Sleep May Be Modifiable Factors Related to Children’s Cognitive Functioning: Evidence From the ABCD Study®

This study used a machine learning framework in conjunction with a large battery of measures from 9,718 school-age children (ages 9–11) from the Adolescent Brain Cognitive Development^SM (ABCD) Study to identify factors associated with fluid cognitive functioning (FCF), or the capacity to learn, solve problems, and adapt to novel situations. The identified algorithm explained 14.74% of the variance in FCF, replicating previously reported socioeconomic and mental health contributors to FCF, and adding novel and potentially modifiable contributors, including extracurricular involvement, screen media activity, and sleep duration. Pragmatic interventions targeting these contributors may enhance cognitive performance and protect against their negative impact on FCF in children.     

Developing Mobile Based Instruction

This paper describes an instructional design class??s experience developing instruction for the mobile web. The class was taught at a southeastern university in the United States in a master??s level computer based instruction course. Two example projects are showcased and student reflections on design issues are highlighted. Additionally, challenges and lessons learned from this experience are described. This case study will benefit those who are considering teaching a course on designing mobile learning; also to those who are considering developing mobile instructional websites.