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The Population of China

The recent census confirms that it stands at a little more than one billion. Through strong measures to reduce the birth rate the government is seeking to have it level off at 1.2 billion...

By Nathan Keyfitz

The Oldest Eukaryotic Cells

All higher organisms are composed of eukaryotic, or nucleated, cells. A review of the fossil record indicates that the eukaryotes originally evolved in the form of unicellular plankton some 1.4 billion years ago...

By Gonzalo Vidal

The Earth's Orbit and the Ice Ages

Periodic variations in the geometry of the earth's orbit have long been considered a possible cause of ice ages. The idea is now supported by a more reliable chronology of glaciations

By Curt Covey

The Structure of Proteins in Biological Membranes

Membrane proteins are embedded in lipid, but they extend into water. The configurations that adapt them to contact with two environments are beginning to be revealed by novel electron-microscope techniques...

By Nigel Unwin and Richard Henderson

The Spectroscopy of Supercooled Gases

A new technique for cooling a gas far below the normal temperature of condensation can dramatically simplify its spectrum. The result gives a highly resolved picture of complex molecular energy states...

By Donald H. Levy

Numbers and Measures in the Earliest Written Records

As early as the end of the fourth mlllennium B. C. proto-Sumerian and proto-Elamite scribes had well-developed systems of numbers and measures. They included precursors of our own decimal system...

By Jöran Friberg

Solitary Bees

Most species of bees are not social like the honeybee. They are solitary, meaning that the female builds her own nest. They play a profoundly important role in pollinating crops and wild plants...

By Suzanne W. T. Batra

The Skill of Typing

How can skilled typists type as fast as they do? A century of study has not produced a definitive answer. A leading hypothesis is that a typist learning to type well learns to make mental processes overlap...

By Timothy A. Salthouse


  • 50 and 100 Years Ago: February 1984

  • Science and the Citizen, February 1984

  • Letters

    Letters, February 1984

  • Recommended

    Books, February 1984

  • Amateur Scientist

    The Amateur Scientist, February 1984

  • Departments

    The Authors, February 1984

  • Computer Recreations, February 1984

  • Bibliography, February 1984

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