American Association for the Advancement of Science
Reproduced with permission from the American Association for the Advancement of Science. Readers may view, browse, and/or
download this material for temporary copying purposes only, provided these uses are for noncommercial personal purposes.
Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed,
displayed, published, or sold in whole or in part, without prior written permission from AAAS.