![]() ![]() When viewed at a finer microscopic size scale though, cardiac tissue is a discrete medium in which electrical impulses propagate discontinuously. The validity of this assumption at a macroscopic size scale is supported by the successful application of macroscopic models such as the cardiac bidomain model, whose predictions are very well in line with experimental observations. Such models are built upon the assumption of an electric syncytium, that is, diffusive material properties of the tissue are continuous. Moreover, the method can be implemented in any standard continuous finite element code with minor effort.Ĭomputational modeling of cardiac electrophysiology at the tissue and organ scale relies mostly on continuum formulations which characterize emergent bioelectric phenomena such as wavefront propagation at a macroscopic size scale. Simulation results demonstrate that the dFE approach accounts for effects induced by microscopic size scale discontinuities, such as the formation of microscopic virtual electrodes, with vast computational savings as compared to high resolution continuous finite element models. In the dFE method this is achieved by imposing infinitely thin lines of electrical insulation along edges of finite elements which approximate the geometry of discontinuities in the intracellular matrix. ![]() In this study, a novel discontinuous finite element (dFE) approach for discretizing the bidomain equations is presented, which accounts for fine-scale structures in a computer model without the need to increase spatial resolution. Current state-of-the-art computer models built upon such datasets account for increasingly finer anatomical details, however, structural discontinuities at the paracellular level are typically discarded in the model generation process, owing to the significant costs which incur when using high resolutions for explicit representation. Many of the strategies used in this complex multicenter trial in the areas of design and analysis, measurement, training, data management, and quality control protocols might be appropriate for adoption in other studies.Advanced medical imaging technologies provide a wealth of information on cardiac anatomy and structure at a paracellular resolution, allowing to identify micro-structural discontinuities which disrupt the intracellular matrix. The CATCH results provided more scientific evidence on the importance of schools in the population approach to health promotion. Data entry error rates were low with less than five errors per 1,000 fields for all forms. Interobserver agreement scores for SOFIT were greater than 90% for 9 of the 11 activities observed. Intraclass correlations for lipid studies were also uniformly high at 0.99. Across all sites, the coefficients of variation for lipids, height, and weight were less than 3%, whereas for skinfolds, they were considerably higher, ranging from 6 to 8%. Measurement error was generally low for all physiologic measures except skinfolds, indicating a high level of reliability. There were no significant differences in the physiological measures. Changes in self-reported dietary, physical activity, and psychosocial measures were significant. Significant increases in moderate to vigorous activity levels in existing physical education classes were made as well. The percentages of calories from fat and saturated fat were reduced significantly more in the intervention school lunches than among the controls. The baseline cohort comprised 5, 106 ethnically diverse third graders followed through fifth grade. Ninety-six elementary schools in four states were randomized to intervention or control conditions. ![]() The Child and Adolescent Trial for Cardiovascular Health (CATCH) was the first multicenter school-based research study to employ the fundamentals of clinical trials including the standardized protocol and Manuals of Operation, a steering committee for study governance, a distributed data system, an extensive quality control system, and a Data and Safety Monitoring Board.ĬATCH tested the effectiveness of changes in school lunches, physical education, smoking policy, curricula, and family activities. ![]()
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