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Antisatellite Weapons

Unless some action is taken soon to restrain the further development of such weapons the positive contributions of satellites to international security will be threatened

By Donald L. Hafner, Kurt Gottfried and Richard L. Garwin

Pre-Columbian Surface Metallurgy

The metalsmiths of Andean cultures knew how to plate copper with gold or silver and how to treat alloys of copper, gold and silver so that the surface of the metal consisted only of gold...

By Heather Lechtman

Mass Extinctions in the Ocean

During brief intervals over the past 700 million years many marine animals and plants have died out. Geologic evidence now suggests that most of the mass extinctions were caused by cooling of the sea...

By Steven M. Stanley

Transposable Genetic Elements in Maize

The mobile genes Barbara McClintock discovered 40 years ago have since been identified in bacteria, other plants and animals. Several maize elements have now been characterized at the molecular level...

By Nina V. Fedoroff

An Atomic Preference between Left and Right

The left- and right-handed versions of an atomic experiment do not always give rise to mirror-symmetric effects. The asymmetry is caused by the weak force between the electrons and the nucleus...

By Lionel Pottier and Marie-Anne Bouchiat

Acoustic and Chemical Signals in the Life Cycle of a Beetle

The subtle interplay of such signals enables the Douglas-fir beetle to attract a mate, to repel intruders and to regulate the density of its population in the great tree of the western forest on which it preys...

By Lee C. Ryker

The Structure and Evolution of Interstellar Grains

The particles of cosmic dust turn out to have an elaborate core-and-mantle construction. In the organic mantle there is evidence of complex, and even violent, chemical processes

By J. Mayo Greenberg

Nuts and Bolts

The notion that a threaded bolt and a matching nut could serve as a fastener dates back only to the 15th century. Today nuts and bolts and ways of making them are still actively evolving...

By Frederick E. Graves


  • 50 and 100 Years Ago: June 1984

  • Letters

    Letters to the Editors, June 1984

  • Recommended

    Books, June 1984

  • Amateur Scientist

    The Amateur Scientist, June 1984

  • Science and the Citizen

    Science and the Citizen, June 1984

  • Departments

    The Authors, June 1984

  • Computer Recreations, June 1984

  • Bibliography, June 1984

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