1. Harvard Division of Health Sciences and Technology, and
2. Division of Engineering and Applied Sciences, Harvard University, Cambridge 02138;
3. Concord Field Station, Museum of Comparative Zoology, Harvard University, Bedford 01730;
4. United States Army Research Institute for Environmental Medicine, Natick 01760; and
5. Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge 02138;
6. Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, Massachusetts 02114