Scientific American Magazine Vol 241 Issue 2

Scientific American

Volume 241, Issue 2

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Features

Bacterial Tests for Potential Carcinogens

New short-term tests can identify environmental agents that cause damage to DNA, the primary event in chemical carcinogenesis. The tests are also valuable for clarifying the mechanism of DNA damage

Corals and Coral Reefs

Tiny coral polyps, living in symbiosis with photosynthetic algae, build huge limestone reefs that harbor more plant and animal species than any other ecosystem on the earth

Supernovas and Star Formation

The explosive death of a massive star may trigger the birth of other stars. Support for this hypothesis comes from theory and from observations of old supernova remnants and meteorites

The Hormonal Control of Behavior in a Lizard

The green anole, often mistakenly called a chameleon, is a good subject for examining how the sex glands and the brain interact in orchestrating the sexual behavior of both males and females

Problems in Physics with many Scales of Length

Physical systems as varied as magnets and fluids are alike in having fluctuations in structure over a vast range of sizes. A novel method called the renormalization group has been invented to explain them

A Pre-Neolithic Farmers' Village on the Euphrates

The Neolithic period is traditionally associated with the emergence of agriculture. At a site in Syria, however, some of the first villagers practiced farming, along with hunting and gathering, even earlier

Progress Toward a Tokamak Fusion Reactor

Recent efforts to confine a superhot hydrogen plasma in a toroidal magnetic bottle have yielded encouraging results. The feasibility of this scheme for a fusion reactor should be known in a few years

The Mathematics of Public-Key Cryptography

The search for privacy in an age of electronic communications has given rise to new methods of encryption. These methods are more practical than older ones and are mathematically more interesting

Departments

Science and the Citizen, August 1979
50 and 100 Years Ago, August 1979
Departments
Bibliography, August 1979
The Authors, August 1979
Letters
Letters to the Editors, August 1979
Amateur Scientist
The Amateur Scientist, August 1979
Reviews
Books, August 1979
Mathematical Recreation
Mathematical Games, August 1979