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Dowda M James F Sallis JF McKenzie TL Rosengard P Kohl HW 《Research quarterly for exercise and sport》2005,76(1):11-19
Dissemination and sustainability of evidence-based physical education programs (PE) has been studied rarely. The sustainability of a health-related PE program (SPARK) was independently evaluated in 111 elementary schools in 7 states. Surveys were mailed to schools that had received SPARK curriculum books, training and follow-up (response rate = 47%). Up to 80% of schools that adopted SPARK PE reported sustained use up to 4 years later. Schools using SPARK had more frequent PE classes. Sustained use was related to support from the principal, not previously having a standard PE program, having adequate equipment, and teachers being physically active. Program sustainability was similar in advantaged and disadvantaged schools. Evidence-based PE programs can be sustained up to 4 years. 相似文献
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Matthew J. Kennedy Harold D. Ladouceur Tiffany Moeller Dickson Kirui Carl A. Batt 《Biomicrofluidics》2012,6(4)
The present work describes the operation and simulation of a microfluidic laminar-flow mixer. Diffusive mixing takes place between a core solution containing lipids in ethanol and a sheath solution containing aqueous buffer, leading to self assembly of liposomes. Present device architecture hydrodynamically focuses the lipid solution into a cylindrical core positioned at the center of a microfluidic channel of 125 × 125-μm2 cross-section. Use of the device produces liposomes in the size range of 100–300 nm, with larger liposomes forming at greater ionic strength in the sheath solution and at lower lipid concentration in the core solution. Finite element simulations compute the concentration distributions of solutes at axial distances of greater than 100 channel widths. These simulations reduce computation time and enable computation at long axial distances by utilizing long hexahedral elements in the axial flow region and fine tetrahedral elements in the hydrodynamic focusing region. Present meshing technique is generally useful for simulation of long microfluidic channels and is fully implementable using comsol Multiphysics. Confocal microscopy provides experimental validation of the simulations using fluorescent solutions containing fluorescein or enhanced green fluorescent protein. 相似文献
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