Scientific American Magazine

For-profit chains of hospitals emerged from a long tradition of commercialism in the US. health-care system. They have thrived on the system's excesses and highlighted its inequities

There is order in chaos: randomness has an underlying geometric form. Chaos imposes fundamental limits on prediction, but it also suggests causal relationships where none were previously suspected

More matter exists than is seen. The motions of stars and galaxies indicate where some of it is; theory suggests there is far more. What and where is it? Particle physics and astrophysics are yielding clues

Part I of a two-part article on the human retroviruses. The first example, found in 1978, causes a rare leukemia. Its discovery laid the groundwork for identifying the related virus that causes AIDS

Dozens of kinds of cells have specialized roles in encoding the visual world. New techniques have made it possible to study the arrangement and interconnections of entire populations of cells

A century ago botanists discovered that a root turned on its side curves downward rapidly in response to gravity, but the mechanism underlying this behavior is only now beginning to be understood

In striving for ever higher speeds the familiar racing shells propelled by eight oarsmen may have to give way to unconventional watercraft. Such a record-setting vehicle was designed and built by the authors

In the second-century Garden Houses of Ostia a rigorous geometry prevailed. From the overall plan to individual mosaics, a particular pattern, rich in philosophical suggestiveness, underlay the design