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Science  21 Jul 2000:
Vol. 289, Issue 5478, pp. 355
DOI: 10.1126/science.289.5478.355b

Probing the Hall effect. In 1879, physicist Edwin Hall discovered how a magnetic field alters the behavior of charge carriers in a metal strip. Today, the Hall effect is a well-known tool for characterizing semiconductors. This new site explains the technique and provides a forum for interested scientists to exchange ideas.

Cell biology mystery.So-called vaults are cellular particles discovered in 1986 and named for their resemblance to the arches of vaulted ceilings. Composed of protein and ribosomal RNA, the grenadelike bits exist in all cells of higher organisms, but their function is unknown. For an introduction, aimed at both students and scientists, to this funny-looking but presumably important structure, check out

Quackery display. The Web site of the Museum of Questionable Medical Devices features a choice selection of “amazingly useless gadgets,” from phrenology devices to radioactive quack cures to the Battle Creek Vibratory

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