2013-8 Selection and Navigation of Overlapping SVG Objects

SVG is a vector graphic image format that can be used with
browsers to deploy dynamic, interactive graphics over the web. We
present a method that enables generalised Selection and Navigation of
Overlapping SVG Objects by toggling pointer-events CSS styles and the
use of the mousewheel, adding another tool developers can use to grant
users greater and more intuitive interaction with SVG images. We also
present several live examples that demonstrate the method in practice,
both on script generated SVG images and an externally generated SVG image

Jimmy Oh

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2013-7 Advanced SVG Graphics from R

The gridSVG package has recently provided an interface for
some more advanced SVG graphics features: gradient fills and pattern
fills, clipping paths, masks, and filters. This report describes a
simple test case for some of these advanced graphics features and then
explores some ideas for making use of these features in Statistical

Paul Murrell and Simon Potter

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2013-6 Testing for Carryover Effects After Cessation of Treatments: A Parallel Design Approach Does Not Work

In interventions it may be important to determine whether the benefits extend beyond the active treatment period. This is clearly of interest for intensive lifestyle interventions, and there are also examples in the pharmaceutical literature. We consider estimation of carryover effects on time-to-event outcomes such as incident hypertension or incident diabetes. These are defined by a noisy measurement exceeding a diagnostic threshold, and diagnosis is followed by interventions that make subsequent measurements useless for treatment comparison.

We present the results of a systematic simulation study to determine the ability of a parallel-group trial design to detect carryover. None of the designs we examined had acceptable Type I error rate; most also had low power. When a treatment is effective during the intervention period, reliable testing for a carryover effect is difficult. Parallel-group designs do not appear to be a feasible approach.

Sarah Gwynn Sturdevant and Thomas Lumley