About the Authors
Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
National Institutes of Health Library, National Institutes of Health, Bethesda, Maryland, United States of America
One of the co-authors, Roberta Scherer, is a PLoS ONE Editorial Board member. This does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials.
Conceived and designed the experiments: RWS PS KD AE. Performed the experiments: RWS PS KD AE. Analyzed the data: RWS. Contributed reagents/materials/analysis tools: KD AE. Wrote the paper: RWS PS KD AE.