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Anti-Ballistic-Missile Systems

The U.S. is now building a "light" ABM system. The authors argue that offensive tactics and cheap penetration aids could nullify the effectiveness of this system and any other visualized so far...

By Hans A. Bethe and Richard L. Garwin

Human Cells and Aging

When normal cells are grown outside the body, their capacity to survive dwindles after a period of time. This deterioration may well represent aging and an ultimate limit to the span of life...

By Leonard Hayflick

Obsidian and the Origins of Trade

Objects made of this volcanic glass are found at many Neolithic sites around the Mediterranean. Spectroscopic analysis indicates that the raw material often came from hundreds of miles away...

By Colin Renfrew, J. E. Dixon and J. R. Cann

The Automatic Synthesis of Proteins

By anchoring an amino acid to a plastic bead one can add other amino acids one by one in automatically controlled steps. This method has already been used to make the small protein insulin...

By R. B. Merrifield

Bilingualism and Information Processing

A person who can speak two languages has clearly mastered two sets of symbols. Experiments that cause the two sets to interact provide important clues to how the mind works

By Paul A. Kolers

Channeling in Crystals

The recent discovery that a beam of charged particles can pass through a crystal lattice in certain directions with surprising case is examined for its theoretical and practical implications...

By Werner Brandt

Pulse-Code Modulation

The growth of communications traffic has enhanced the attractiveness of this method, which converts messages into binary digits that can then be transmitted in the form of closely spaced electrical pulses...

By J. S. Mayo

The Adjustable Brain of Hibernators

The unique state of torpor that some mammalian species can attain is the result of a complex chain of events. It now appears that changes in the usual functioning of the brain underlie these events...

By N. Mrosovsky


  • 50 and 100 Years Ago: March 1968

  • Science and the Citizen: March 1968

  • Letters

    Letters to the Editors, March 1968

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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