Gross motor skills and sports participation of children with visual impairments

Gross motor skill performance of children with visual impairments and its association with the degree of visual impairment and sports participation was examined. Twenty children with visual impairments (M age = 9.2 years, SD = 1.5) and 100 sighted children (M age = 9.1 years, SD = 1.5) from mainstream schools participated. The results showed that children with visual impairments had significantly lower object control but not locomotor skill scores than the sighted children. No significant differences were found between children with a moderate and severe visual impairment. Children with visual impairments who participated in sports had significantly higher object control skill scores than those who did not. No significant associations between motor skills and sports participation were found in the sighted children.     

Principals’ Perceptions of Barriers to Teacher Dismissal

Although scholars and popular press writers are critical of school district failures to remove inadequately performing teachers, little has been said about the thinking of principals on this issue. Because principals are the front-line implementers of evaluation policy, their beliefs about barriers (real or perceived) are likely to influence their actions. This study asked elementary and middle school principals in the state of Oregon to identify barriers to deal effectively with inadequately performing teachers. Results demonstrated that principals believe teacher unions to be the most significant barrier, and blame the union representatives more often than the language of the negotiated contract. In addition, principals identify the amount of time required to engage in the process as a barrier. Continued study of principal beliefs about these factors may suggest (1) areas of needed reform in the implementation of evaluation and (2) administrative training needs.     

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

The mechanical behavior of cells offers insight into many aspects of their properties. We propose an approach to the mechanical analysis of cells that uses a combination of electromanipulation for stimulus and capacitance for sensing. To demonstrate this approach, polystyrene spheres and yeast cells flowing in a 25 μm×100 μm microfluidic channel were detected by a perpendicular pair of gold thin film electrodes in the channel, spaced 25 μm apart. The presence of cells was detected by capacitance changes between the gold electrodes. The capacitance sensor was a resonant coaxial radio frequency cavity (2.3 GHz) coupled to the electrodes. The presence of yeast cells (Saccharomyces cerevisiae) and polystyrene spheres resulted in capacitance changes of approximately 10 and 100 attoFarad (aF), respectively, with an achieved capacitance resolution of less than 2 aF in a 30 Hz bandwidth. The resolution is better than previously reported in the literature, and the capacitance changes are in agreement with values estimated by finite element simulations. Yeast cells were trapped using dielectrophoretic forces by applying a 3 V signal at 1 MHz between the electrodes. After trapping, the cells were displaced using amplitude and frequency modulated voltages to produce modulated dielectrophoretic forces. Repetitive displacement and relaxation of these cells was observed using both capacitance and video microscopy.