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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.

The opinions, findings, and conclusions or recommendations contained in this document are those of the authors and do not necessarily reflect the views of the National Science Foundation or the U.S. Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the U.S. government. Supported by the National Science Foundation under Award No. 0106060; the U.S. Geological Survey, Department of the Interior, under Award No. 01HQAG0216; and the National Aeronautics and Space Administration under Award No. NNS04AA14G.

International Standard Book Number-13: 978-0-309-10470-8 (Book)

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International Standard Book Number-13: 978-0-309-66852-1 (PDF)

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Cover: Design by Michele de la Menardiere. The top right is an image illustrating successful models of blood clotting (image courtesy of Nicole Rager-Fuller, National Science Foundation). The top left image is a high resolution photo of fluorite (image courtesy of U.S. Geological Survey; image source, AGI Image Bank,

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