Berlin Heart EXCOR Pediatric ventricular assist device Investigational Device Exemption study: study design and rationale.

Background: Currently, there are no Food and Drug Administration-approved devices available that can provide long-term mechanical circulatory support to smaller children with severe heart failure as a bridge to heart transplant (HT). In recent years, the Berlin Heart EXCOR Pediatric ventricular assist device (VAD) has emerged as a potential treatment option. Systematic data on the safety and efficacy of the EXCOR are limited.

Using SAS to conduct nonparametric residual bootstrap multilevel modeling with a small number of groups.

In multilevel modeling, researchers often encounter data with a relatively small number of units at the higher levels. As a result, of this and/or non-normality of the residuals, model parameter estimates, particularly the variance components and standard errors of parameter estimates at the group level, may be biased, thus the corresponding statistical inferences may not be trustworthy. This problem can be addressed by using bootstrap methods to estimate the standard errors of the parameter estimates for significance testing.

Multivariate cubic spline smoothing in multiple prediction.

Given longitudinal data for several variables, including a given outcome variable, it is desired to predict the outcome for a specific individual, or more generally experimental unit, in such a way that the predicted value is both accurate and resistant (i.e. has good cross-validation).

Towers of Hanoi and London: is the nonshared variance due to differences in task administration?

Although it has been assumed that the Tower of Hanoi and Tower of London are more or less interchangeable tasks dependent on executive function, a series of studies in our laboratory have indicated substantial nonshared variance between the performances on the two tasks. The purpose of the present study was to examine how much methods of administration, such as number of trials per problem, contribute to this nonshared variance. A new one-trial version of the Tower of Hanoi was developed to be identical to the Tower of London in four procedural characteristics.