Experimental validation of numerical study on thermoelectric-based heating in an integrated centrifugal microfluidic platform for polymerase chain reaction amplification

A comprehensive study involving numerical analysis and experimental validation of temperature transients within a microchamber was performed for thermocycling operation in an integrated centrifugal microfluidic platform for polymerase chain reaction (PCR) amplification. Controlled heating and cooling of biological samples are essential processes in many sample preparation and detection steps for micro-total analysis systems. Specifically, the PCR process relies on highly controllable and uniform heating of nucleic acid samples for successful and efficient amplification. In these miniaturized systems, the heating process is often performed more rapidly, making the temperature control more difficult, and adding complexity to the integrated hardware system. To gain further insight into the complex temperature profiles within the PCR microchamber, numerical simulations using computational fluid dynamics and computational heat transfer were performed. The designed integrated centrifugal microfluidics platform utilizes thermoelectrics for ice-valving and thermocycling for PCR amplification. Embedded micro-thermocouples were used to record the static and dynamic thermal responses in the experiments. The data collected was subsequently used for computational validation of the numerical predictions for the system response during thermocycling, and these simulations were found to be in agreement with the experimental data to within ∼97%. When thermal contact resistance values were incorporated in the simulations, the numerical predictions were found to be in agreement with the experimental data to within ∼99.9%. This in-depth numerical modeling and experimental validation of a complex single-sided heating platform provide insights into hardware and system design for multi-layered polymer microfluidic systems. In addition, the biological capability along with the practical feasibility of the integrated system is demonstrated by successfully performing PCR amplification of a Group B Streptococcus gene.     

Children's Activity Rating Scale (CARS): Description and Calibration

Abstract

A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO₂s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO₂s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml kg BW^?1 min^?1 (1 to 5.42 METS; 145% to 80.6% of VO₂max). Mean heart rates ranged from 89 to 183 b min^?1 for activities in Levels 1-5. VO₂s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discriminates between levels of energy expenditure, and can be used by trained observers to reliably evaluate physical activity and estimate energy expenditure of young children.     

An Analysis of the Relationship between Somatotype and Personality Traits of College Women

Abstract

The underlying rationale for the study was based on the conviction that biological factors are important in accounting for human behavior. This study was undertaken to compare the results of selected personality traits with the somatotypes of college women. Somatotypes were determined by the use of somatotype ratings as established by Sheldon. The personality profiles were determined by two personality measuring instruments: (a) the Sixteen Personality Factor Questionnaire, and (b) the California Psychological Inventory. Of the 23 hypotheses which were arbitrarily derived from Sheldon's work on physique and temperament of men, only one proved to be tenable. This tenable hypothesis stated that the component of mesomorphy is significantly correlated with the second order Factor I of the 16 PF (Low Anxiety).     

Effect of Guided Practice on Overhand-Throw Ball Velocities of Kindergarten Children

Abstract

Forty-five children from two intact kindergartens in one school were randomly assigned by sex to (a) an experimental group which received a movement program that included 120 min of guided practice in the overhand throw; or (b) a control group which received the same movement program but no exposure to the throw. A third group (N = 24), randomly selected by sex from a comparable school, received no movement program. Before and after the eight-week instructional period, ten trials of each child's overhand throw for force were filmed. Horizontal ball velocities were simultaneously recorded. ANOVAs on pre- and posttest ball velocities for each sex within each treatment group revealed no significant practice effect over ten trials (p > .05); thus, the trial mean was used as each subject's score. Two-way ANOVAs (treatment X sex) on the pre- and posttest data indicated no significant velocity differences (p > .05) between groups either before or after instruction. Boys had significantly greater velocities than girls (p < .05). Eight weeks of instruction that included 120 min of guided practice in the overarm throw did not significantly change the ball velocities of kindergarten children when compared to two groups with no formal throwing experience.     

Number of Reinforcements and Memory Trace for Kinesthetically Monitored Force Reproduction

Abstract

The effect of the number of reinforcements on the memory trace for a kinesthetically monitored force reproduction task was studied. Sixty college women were divided by a balanced order into three groups of 20 each. One group had one reinforcement, one had five reinforcements, and the third had nine reinforcements. The reproduction attempt was either immediate or after a 30-sec. delay. Analysis of variance for constant error indicated that multiple reinforcements improved the accuracy of performance for immediate reproduction but that the improvement was not retained over a retention interval of 30 sec. The tendency to overshoot the standard occurred for both the immediate and delayed reproduction conditions.     

Parenting and Child DRD4 Genotype Interact to Predict Children’s Early Emerging Effortful Control

Effortful control (EC), or the trait‐like capacity to regulate dominant responses, has important implications for children’s development. Although genetic factors and parenting likely influence EC, few studies have examined whether they interact to predict its development. This study examined whether the DRD4 exon III variable number tandem repeat polymorphism moderated the relation between parenting and children’s EC. Three hundred and eighty‐two 3‐year‐olds and primary caregivers completed behavioral tasks assessing children’s EC and parenting. Children’s DRD4 genotypes moderated the relation between parenting and EC: Children with at least one 7‐repeat allele displayed lower EC in the context of negative parenting than children without this allele. These findings suggest opportunities for modifying early risk for low EC.     

How inconvenient assumptions affect preservice teachers’ uptake of new interactional patterns in mathematics: analysis and aspiration through a bifocal lens

In this paper, I highlight the inadequacies of contemporary theoretical and philosophical orthodoxies to fully address pedagogic change. The required change is in mathematics education, and it has to do with enabling preservice teachers, upon graduation, to rework extant power relations in implementing new interactional patterns that centre the mathematics and the learner in dynamic, productive interaction. I interpret data from published research and my own teaching using psychological, overlaid with poststructuralist, constructs of the relationship between knowledge and action. In data interpretation I read through the words for a psychological interpretation (meaning), and I look at the words for poststructuralist indications of subjectification and identity formation (related to how well students recognise themselves as full participants in the combined discourses of mathematics and education). I have my cake and eat it; contradictory notions of the learner and learning to teach in innovative ways are held together to demonstrate (a) how it can happen that a teacher educator’s aspirations can be held ransom to constituted assumptions that inconveniently work against change, and (b) how the recognition that humanist assumptions, mathematical proficiency and agency are discursively constituted (Davies, 1990) can suggest avenues for change in teacher education.