The role of memory aids in two instructional paradigms: Learning and utilization of logical rules

One hundred and thirty-two 10th graders performed either a conjunetive or biconditional rule task in one of six conditions defined by a 2 (tasks: attribute-identification versus rule-learning) by 3 (memory aids: 0 versus 3 versus 6) factorial design. Learners' attribute-identification was facilitated when six memory aids were made available, especially given the biconditional rule, but not when three aids were available. This effect was attributed to the facilitative role of six memory aids in the process of eliminating irrelevant dimensions. The acquisition of the biconditional rule was a linear function of the number of memory aids; but that of the conjunctive rule was not differentially affected by the memory aids. This interaction was attributed to the facilitative role of memory aids in the formation of a relatively complex one, not in the identification of a familiar, easy one.     

Effects of the model's skill level on observational motor learning.

Observation of a model prior to physical practice often facilitates the acquisition of motor skills. The majority of research studies on observational motor learning has used a skilled model for the demonstration. Recent research, however, suggests that observing an unskilled (learning) model may also be effective. The experiment reported here compared motor skill acquisition following observation of a learning model or a skilled model to the performance of subjects who lacked the benefit of observation. The task was to play a computer tracking game. Subjects were tested in pairs. Observers watched either a skilled or a learning model perform 3 trials. The observers then practiced the game for 3 trials. Observation of another 12 trials was followed by 12 more practice trials. Substantial observational learning was found, as both groups of observers performed better than the learning models after both the 3 initial trials of observation and after 12 more observation trials. However, there were no differences due to observing the skilled or the learning model. These findings are discussed in relation to theoretical issues of observational learning.     

Electrowetting on dielectric driven droplet resonance and mixing enhancement in parallel-plate configuration

This study experimentally verifies that the mixing process in a droplet can be enhanced by driving the droplet at resonant frequencies and at alternating driving frequencies using a parallel-plate electrowetting on dielectric device. The mixing time, which is defined as the time required for reaching the well-mixed state, in a resonant droplet is found to be significantly shorter than that in a non-resonant droplet. Besides, it is also found that a higher driving potential leads to a better mixing effect, especially at resonant frequencies. Furthermore, when a droplet is driven by alternating two driving frequencies, especially two resonant frequencies, the mixing efficiency is found to be significantly enhanced for a specific alternating duration of these two frequencies.     

Resistive pulse sensing of magnetic beads and supraparticle structures using tunable pores

Tunable pores (TPs) have been used for resistive pulse sensing of 1 μm superparamagnetic beads, both dispersed and within a magnetic field. Upon application of this field, magnetic supraparticle structures (SPSs) were observed. Onset of aggregation was most effectively indicated by an increase in the mean event magnitude, with data collected using an automated thresholding method. Simulations enabled discrimination between resistive pulses caused by dimers and individual particles. Distinct but time-correlated peaks were often observed, suggesting that SPSs became separated in pressure-driven flow focused at the pore constriction. The distinct properties of magnetophoretic and pressure-driven transport mechanisms can explain variations in the event rate when particles move through an asymmetric pore in either direction, with or without a magnetic field applied. Use of TPs for resistive pulse sensing holds potential for efficient, versatile analysis and measurement of nano- and microparticles, while magnetic beads and particle aggregation play important roles in many prospective biosensing applications.     

Rapid and cost-effective fabrication of selectively permeable calcium-alginate microfluidic device using ��modified�� embedded template method

In this paper, we have presented a non-lithographic embedded template method for rapid and cost-effective fabrication of a selectively permeable calcium-alginate (Ca-alginate) based microfluidic device with long serpentine delay channel. To demonstrate the versatility of the presented method, we have demonstrated two different strategies to fabricate serpentine long delay channels without using any sophisticated microfabrication techniques, in formal lab atmosphere. The procedure presented here, also, enables the preparation of a multilayered microfluidic device with channels of varying dimensions, in a single device without using any sophisticated micromachining instrumentation. In addition, we have also qualitatively studied the diffusion of small and large molecules from a Ca-alginate based microfluidic device and proposed a method to effectively control the out-flow of macro biomolecules from the crosslinked Ca-alginate matrix to create a selectively permeable matrix required for various biological and biomimetic applications, as mentioned in the Introduction section of this work.