Cardiac magnetic resonance imaging (MRI) is a noninvasive technique used to accurately and reproducibly measure biological parameters such as left ventricular mass. However, some subjects either ...refuse or are unable to complete testing, and the impact of excluding these missing data from predictive models is unknown.
Multiple imputation was applied to cardiac MRI data that were previously analyzed using a complete case approach. The model variables - 10 traditional cardiovascular risk factors and five sociodemographic variables - were used as a basis for imputation. Men and women were imputed separately. The primary focus was assessing the change in the cardiovascular predictors of left ventricular geometry and systolic function.
Although 27% of participants were missing cardiac MRI data, multiple imputation returned results similar to those of a complete case analysis. These results were robust to the point of including additional variables in the imputation analysis above and beyond the model variables. The degree of variance explained by the models increased marginally but the statistical inference was altered for only two predictors out of 53 cardiovascular risk factors using multiple imputation.
The results suggest that the cardiac MRI data in the Multi-Ethnic Study of Atherosclerosis (MESA) do not substantively change when missing data are handled using multiple imputation. Future analyses of cardiac MRI data may consider the complete case approach to be adequate despite the high rate of missing data in this population.
She's very accurate from 15 to 18 feet away and likely projects as a small forward or a wing at the college level. Ed Wissing thinks she could play at the NCAA Division I level. She's not quite big ...enough to play in the post at that level, but Todhunter thinks there is a chance as a wing. Wissing is also trying to find more ways to utilize all of her abilities. In any given game Todhunter can move between the low post, the high post or the wing. She gets plenty of practice during the offseason. Todhunter split time between two teams this summer, the Northwest Blazers and the Evergreen Express, and also took part in a few viewing tournaments for college scouts.
Harris, Miles and Paine ask: What happens when the texts that students write become the focus of a writing course? In response, a distinguished group of scholar/teachers suggests that teaching with ...students texts is not simply a classroom technique, but a way of working with writing that defines composition as a field.InTeaching with Student Texts, authors discuss ways of revaluing student writing as intellectual work, of circulating student texts in the classroom and beyond, and of changing our classroom practices by bringing student writings to the table. Together, these essays articulate a variety of ways that student texts can take a central place in classroom work and can, in the process, redefine the ways our field talks about writing.
This dissertation presents two performance measures for algorithms: processor-time-minimality and period-processor-time-minimality. These measures quantify the parallelism of an algorithm. ...Processor-time-minimality indicates the minimum number of processors that are sufficient to extract the dag's maximum parallelism. Using this measure, tight bounds are proved for a number of fundamental algorithms, represented as directed acyclic graphs (dags): a matrix multiplication algorithm (represented as a rectilinear mesh), a Tensor product algorithm (represented as a 4D cubical mesh), a Gaussian elimination algorithm, and a transitive closure algorithm. Period-processor-time-minimality measures the maximum throughput obtainable when using the minimum number of processing elements that are sufficient to extract the dag's maximum parallelism. Using this measure, tight bounds are proved for a square matrix multiplication algorithm (represented as a cubical mesh).
The relationship between problem solving and a variety of expectancies was explored to assess and compare the accuracy of three types of expectancies. Before performing an anagram test, students ...completed questionnaires to assess their expectancies that (a) a technique would be effective if used (outcome), (b) they would be able to perform the technique (self-efficacy), and (c) they would actually implement the technique (compliance) in solving a problem. Results indicated that for certain groups of problem solving strategies, after experience with the task, outcome and compliance expectancies were significantly related to subsequent performance, but only self-efficacy expectancies were related to both prior and subsequent performance. After extensive experience, self-efficacy and outcome expectancies lost their predictive edge over compliance expectancies while compliance expectancies demonstrated significant ability to predict performance. This suggests that subjects may find it more cognitively economical to converge both outcome and self-efficacy expectancies into a single compliance expectancy. Additionally, certain strategies rated by most subjects as ineffective were rated high in effectiveness by subjects who were later less successful at solving anagrams, creating an inverse outcome expectancy-performance relation. This replicated an earlier finding in Yates, Casey, Schoonover, and Gray (1990).
