The Research Letter is intended to provide a means to communicate short original research in a highly focused manner. Important, fast-breaking research that lends itself to a short communication and that can be reviewed rapidly is our objective. Papers should not exceed 600 words of text and should have fewer than 6 references. A single table or figure may be included. In general, Research Letters should be divided into the following sections: an introduction (with no heading), Methods, Results, and Comment. Research Letters should be double spaced and a word count should be provided with each letter.