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Cryptography and Computer Privacy

Computer systems in general and personal "data banks" in particular need protection. This can be achieved by enciphering all material and authenticating the legitimate origin of any command to the computer

By Horst Feistel

The Role of the Heartbeat in the Relations between Mother and Infant

Most mothers exhibit a natural preference for holding their baby on the left side of their chest. There is reason to believe that the sound of the adult heart has a soothing effect on the infant

By Lee Salk

Two-Dimensional Matter

Films only a molecule thick vapor-deposited on atomically clean, highly uniform crystal surfaces serve as physical analogues of theoretically ideal two-dimensional systems

By J. C. Dash

Roots

The leaves of a plant gather the sunlight and carbon dioxide needed for photosynthesis; the roots gather the water and also the minerals that are essential not only to the plant but also to all animal life

By Emanuel Epstein

The Evolution of the Indian Ocean

A 75-million-year magnetic record in the floor of the Indian Ocean reveals how India was rafted northward for 5,000 kilometers before it collided with Asia. The encounter gave rise to the Himalayas

By D. P. McKenzie and J. G. Sclater

Confirmation

For centuries investigators have been testing, confirming and disconfirming hypotheses by observation and experimentation. Yet the logic of the process is still far from being understood

By Wesley C. Salmon

Galileo's Discovery of the Law of Free Fall

It has been thought that he erroneously assumed that the velocities of a falling body were proportional to distances. A new manuscript shows that he treated them correctly as being proportional to time

By Stillman Drake

The Infrared Receptors of Snakes

The snakes of two large families have sensitive organs that can detect the heat radiation emitted by their prey. The performance of these detectors is investigated with the aid of an infrared laser

By John F. Harris and R. Igor Gamow

Departments

  • 50 and 100 years ago, May 1973

  • Science and the Citizen, May 1973

  • Letters

    Letters to the Editors, May 1973

  • Recommended

    Books, May 1973

  • Mathematical Recreation

    Mathematical Games, May 1973

  • Amateur Scientist

    The Amateur Scientist, May 1973

  • Departments

    The Authors, May 1973

  • Bibliography, May 1973

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