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Economic Growth in the U.S.S.R.

Statistics on Soviet output, compiled by economists in the U.S., are analyzed to reveal a remarkably high annual rate of growth. An attempt is made to determine how this high rate was attained

By Raymond P. Powell

Transplanted Nuclei and Cell Differentiation

The nucleus of a cell from a frog's intestine is transplanted into a frog's egg and gives rise to a normal frog. Such experiments aid the study of how genes are controlled during embryonic development

By J. B. Gurdon

Radio Signals from Hydroxyl Radicals

Intense emission signals from space at microwave frequencies characteristic of hydroxyl (OH) radicals may be generated by a kind of maser action in the gaseous envelopes of very young stars

By Alan H. Barrett

Sea-Floor Spreading

Geophysical phenomena ranging from earthquakes to continental drift are being explained by a new theory that gives promise of eventually relating geomagnetism and the earth's internal and orbital dynamics

By J. R. Heirtzler


A kind of grounded cloud, fog can halt sea, air and highway travel. When combined with air pollutants, it can be lethal. Ways are known, however, not only to dissipate fog but also to inhibit its formation

By Joel N. Myers

The Relativism of Absolute Judgments

In which it is proposed that happiness is a negatively skewed distribution. Experiments demonstrate how judgments of personal satisfaction depend on the frequency of different experiences

By Allen Parducci

Resonant Combustion in Rockets

The variety of physical and chemical processes taking place during the release of energy in a rocket engine may create conditions for oscillations to build up to large amplitudes

By J. George Sotter and Gary A. Flandro

Human Stones

Many pathological minerals can form within the body. The incidence of stones in the kidneys, the urinary bladder and the gall bladder shows remarkable variations with respect to geography and history

By Kathleen Lonsdale


  • 50 and 100 Years Ago: December 1968

  • Science and the Citizen: December 1968

  • Letters

    Letters to the Editors: December 1968

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Annual Index

  • Bibliography

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Scientific American Health & Medicine

Scientific American Health & Medicine