Luann Udell of Keene, NH, used just that method when her son, Doug, was 12.

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"Ivins was as mild as they come, " said Luann Battersby, a former microbiologist who worked with Ivins at Fort Detrick.

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Ted Bunch worked with Luann Becker, of the University of Hawaii, Honolulu, and Robert Poreda, of the University of Rochester, New York, on the research, which is published in the Proceedings of the National Academy of Sciences.

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