THE NATIONAL ACADEMIES PRESS
500 Fifth Street, N.W. Washington, DC 20001
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
This study was supported by a grant from the Alfred P. Sloan Foundation. The views expressed in this publication are those of the authors and do not necessarily reflect the views of the Alfred P. Sloan Foundation.
International Standard Book Number-13: 978-0-309-14960-0
International Standard Book Number-10: 0-309-14960-6
Copies of this report are available from the
National Academies Press,
500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu.
Copyright 2010 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America