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Government Investment in Health Care

The delivery of health care will remain unsatisfactory and its cost will continue to rise until the U.S. invests in capacity for a real health-care system. That will require some hard political decisions...

By Irving J. Lewis

A High-Resolution Scanning Electron Microscope

The goal of seeing individual atoms with an electron microscope has been achieved with an instrument that extracts a maximum of information from the electrons after they strike their target...

By Albert V. Crewe

Early Man in The Andes

Stone tools in highland Peru indicate that men lived there 22,000 years ago, almost twice the old estimate. They also imply that the first cultural traditions of the New World had their roots in Asia...

By Richard S. MacNeish

Advances in Pattern Recognition

Automatic methods of interpreting patterns of various kinds are currently under investigation. An experimental reading machine that requires no prior knowledge of character shapes is described...

By Richard G. Casey and George Nagy

Annual Biological Clocks

Many organisms have a built-in circadian, or daily, clock. It has now been demonstrated that some also have a circannual, or yearly, clock that operates even when environmental signals are eliminated...

By Eric T. Pengelley and Sally J. Asmundson

Superconductivity at High Pressure

Experiments designed to measure the effects of compression on the superconducting properties of certain metals may lead to the creation of new, higher-temperature superconductors

By N. B. Brandt and N. I. Ginzburg


The internal structure of a hailstone tells the history of its formation. This structure is made visible by cutting a section of the stone and placing it between crossed polarizing filters...

By Charles Knight and Nancy Knight

The Mapping of Human Chromosomes

The goal is to locate a gene In relation to others and to establish which of the 23 chromosome pairs carries it. This is done primarily by applying statistical techniques to data on inheritance of traits...

By Victor A. McKusick


  • 50 and 100 Years Ago: April 1971

  • Science and the Citizen: April 1971

  • Letters

    Letters to the Editors, April 1971

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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