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The Origins of Hypodermic Medication

The injection of drugs is now taken for granted, but originally it was a bold innovation. The man who introduced the procedure some 120 years ago sought only to relieve the pain of neuralgia

By Norman Howard-Jones

The Nature of Pulsars

It is generally agreed that these flickering objects are neutron stars in rapid rotation. What seems to be such a star in the Crab Nebula may well account for some of the nebula's puzzling features

By Jeremiah P. Ostriker

The Global Circulation of Atmospheric Pollutants

Worldwide wind and temperature patterns and the behavior of trace substances are studied in an effort to learn what effect changes in the atmosphere caused by man may have on the earth's climate

By Reginald E. Newell

Stress and Behavior

The chain of pituitary and adrenal hormones that regulates responses to stress plays a major role in learning and other behaviors. It n1ay be that effective behavior depends on some optimum level of stress

By Seymour Levine

Reflectors in Fishes

Many fishes are able to secrete nitrogenous compounds that form mirror-like layers of reflective crystals. In the scales and the skin the layers are displays or camouflage; elsewhere they aid vision

By Eric Denton

Induced Mutations in Plants

The intentional exposure of seeds to mutagens has produced many new characteristics for the intensified breeding of plants. This procedure has played an important part in the “green revolution”

By Björn Sigurbjörnsson

Circuit Breakers

The problem is how to interrupt a high-voltage current quickly but not too quickly. The answer lies in cultivating and then quickly dousing the arc that forms when the circuit is broken

By Werner Rieder

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