• Digital Millennium Copyright Act Policy & Contact Information
• Privacy Statement
• Terms of Use

Copyright © 2014 National Academy of Sciences. All rights reserved.

Unless otherwise indicated, all materials on these pages are copyrighted by the National Academy of Sciences. All rights reserved. No part of these pages, either text or image may be used for any purpose other than personal use. Therefore, reproduction, modification, storage in a retrieval system or retransmission, in any form or by any means, electronic, mechanical or otherwise, for reasons other than personal use, is strictly prohibited without prior written permission.

The identifier "the National Academies" refers collectively to the National Academy of Sciences, National Academy of Engineering, Institute of Medicine and National Research Council.

General inquiries should be directed to our Web feedback box, accessible from this link or from the footer at the bottom of most pages on our site.

Messages posted to some areas of the National Academies Web site are not private. If you post a message, anyone with access to the message area can read it, and your e-mail address becomes available to anyone who browses or uses the message area. Please keep in mind that the National Academies cannot control who sends you e-mail as a result of postings to this service.