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X-Ray Imaging with Coded Masks

A variant of the pinhole camera that has many apertures arranged in a peculiar pattern can image high-energy X-ray sources, such as plasmas in reactors and black holes in space

By Gerald K. Skinner

The High Fidelity of DNA Duplication

Generation after generation, through countless cell divisions, the genetic heritage of living things is scrupulously preserved in DNA. Why are so few mistakes made when the DNA is copied?

By Miroslav Radman and Robert Wagner

The Challenge of Acid Rain

Acid rain's effects in soil and water leave no doubt about the need to control its causes. Now advances in technology have yielded environmentally and economically attractive solutions

By Volker A. Mohnen

Perceiving Shape from Shading

Shading produces a compelling perception of three-dimensional shape. One way the brain simplifies the task of interpreting shading is by assuming a single light source

By Vilayanur S. Ramachandran

Measuring Crustal Deformation in the American West

Continental crust is actively deforming as the Pacific and North America plates slide past each other. Direct measurements of the process rely on extraterrestrial reference points such as quasars

By Thomas H. Jordan and J. Bernard Minster

Light-Activated Drugs

A patient ingests an inert substance. The substance is removed from the body in a small amount of blood and activated by light. The result? Effective treatment for a stubborn cancer

By Richard L. Edelson

Dr. Atanasoff's Computer

The men who for decades were credited with inventing the first electronic digital computers were not, in fact, first. That honor belongs to a once forgotten physicist named John V. Atanasof

By Allan R. Mackintosh


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