Despite myriad challenges, clinicians see room for progress.
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Communicated by Frans B. M. de Waal, Emory University, Atlanta, GA, October 30, 2008 (received for review July 21, 2008)
Communicated by Frans B. M. de Waal, Emory University, Atlanta, GA, October 30, 2008 (received for review July 21, 2008)
Author contributions: F.R., Z.V., and L. Huber designed research; F.R. and L. Horn performed research; F.R. analyzed data; and F.R. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0810957105/DCSupplemental.
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