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Page ii
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. The members of the committee responsible for the
report were chosen for their special competences and with regard
for appropriate balance.
This report has been reviewed by a group other than the authors
according to procedures approved by a Report Review Committee
consisting of members of the National Academy of Sciences, the
National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit,
self-perpetuating society of distinguished scholars engaged in
scientific and engineering research, dedicated to the furtherance
of science and technology and to their use for the general welfare.
Upon the authority of the charter granted to it by the Congress in
1863, the Academy has a mandate that requires it to advise the
federal government on scientific and technical matters. Dr. Bruce
Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964,
under the charter of the National Academy of Sciences, as a
parallel organization of outstanding engineers. It is autonomous in
its administration and in the selection of its members, sharing
with the National Academy of Sciences the responsibility for
advising the federal government. The National Academy of
Engineering also sponsors engineering programs aimed at meeting
national needs, encourages education and research, and recognizes
the superior achievements of engineers. Dr. William A. Wulf is
president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the
National Academy of Sciences to secure the services of eminent
members of appropriate professions in the examination of policy
matters pertaining to the health of the public. The Institute acts
under the responsibility given to the National Academy of Sciences
by its congressional charter to be an adviser to the federal
government and, upon its own initiative, to identify issues of
medical care, research, and education. Dr. Kenneth I. Shine is
president of the Institute of Medicine.
The National Research Council was organized by the National
Academy of Sciences in 1916 to associate the broad community of
science and technology with the Academy's purposes of furthering
knowledge and advising the federal government. Functioning in
accordance with general policies determined by the Academy, the
Council has become the principal operating agency of both the
National Academy of Sciences and the National Academy of
Engineering in providing services to the government, the public,
and the scientific and engineering communities. The Council is
administered jointly by both Academies and the Institute of
Medicine. Dr. Bruce Alberts and Dr. William A. Wulf are chairman
and vice chairman, respectively, of the National Research
Council.
Support for this project was provided by the Defense Advanced
Research Projects Agency. Any opinions, findings, conclusions, or
recommendations expressed in this material are those of the authors
and do not necessarily reflect the views of the sponsors.
Library of Congress Catalog Card Number 97-80464
International Standard Book Number 0-309-05946-1
Copyright 1997 by the National Academy of Sciences. All rights
reserved.
Additional copies of this report are available from:
National Academy Press
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Box 285
Washington, DC 20055
800-624-6242
202-334-3313 (in the Washington metropolitan area)
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Printed in the United States of America