Sean Morrison, Children's Research Institute, and Robert A.J. Signer, University of Texas Southweste (image) UT Southwestern Medical Center Share Print E-Mail Caption This photo shows Dr. Sean Morrison, Director of the Children's Research Institute and senior author of the study, right, and Dr. Robert A.J. Signer, a postdoctoral research fellow and the study's first author. Credit University of Texas Southwestern Medical Center Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.