2012-11 Generating Animation Sequence Descriptions

This report describes the animaker package for generating descriptions of animation sequences. An animation sequence is composed by combining atomic animations in series to create sequence animations or in parallel to create track animations. Functions are provided for manipulating animation sequences, generating timing schemes from animation sequences, and producing diagrams to visualise animation sequences.

Paul Murrell and Simon Potter


2012-9 Writing grid Extensions

New hook functions, makeContext() and makeContent(), have been added to the grid graphics package. These functions allow an alternative approach to developing custom grobs when a grob can only decide what to draw at drawing time rather than when the grob is created. For custom grobs that are based on this new approach, the

grid.force() function provides access to low-level grobs that are otherwise invisible because they are only generated at drawing time.

These functions lead to greater flexibility in the development of custom grobs and more power to modify the result after drawing is complete.

Paul Murrell


2012-8 Meta-analysis of a rare-variant association test

Genome-wide assocation studies have often been carried out by meta-analysis rather than by pooling individual-level data.  For one-dimensional parameter estimates and the corresponding tests of association these meta-analyses lead to essentially no loss of information relative to pooling individual data.  The situation is different for multi-parameter tests, such as the omnidirectional rare-variant tests being used in resequencing studies.  In this paper we consider one popular rare-variant test, a version of the sequence kernel association test.  We show that meta-analyses based on the $p$-value or test statistic from each contributing study are importantly less efficient than an analysis pooling individual data, but that a more sophisticated meta-analysis retains full efficiency. The meta-analysis is based on a reformulation of the test that links it to tests used in survey analysis.

Thomas Lumley, Jennifer Brody, Josee Dupuis, Adrienne Cupples