The Delivery of Medical Care
Medical care in the U.S. is expensive and poorly distributed, and national health insurance will make things worse. What is needed is an innovative system in which the sick are separated from the well...
Features
Repeated Segments of DNA
In cells of higher organisms a significant fraction of the genetic material appears in as many as a million identical or very similar copies. The origin and function of repetitive DNA remain unknown...
The Red Sea Hot Brines
Three pools of very salty hot water have accumulated at the bottom of the Red Sea. The sediments in these pools are rich in minerals deposited from the brines
Chemistry by Computer
Computed quantum-mechanical models of the electronic structure of atoms and molecules can provide a reliable and comprehensive alternative to the traditional experimental approach to chemistry...
Environment
Pesticides and the Reproduction of Birds
High concentrations of chlorinated hydrocarbon residues accumulate in such flesh-eaters as hawks and pelicans. Among the results are upsets in normal breeding behavior and eggs too fragile to survive...
How is Muscle Turned On and Off?
Work with muscle fiber of a giant barnacle supports the hypothesis that a flow of calcium ions in response to a nerve signal gives rise to contraction, and that withdrawal of the ions results in relaxation...
Hyperactive Children
Certain children are more than usually restless, noisy, destructive and distractible. Their behavior appears to be a distinct disease syndrome that may well be innate
Liquid-Crystal Display Devices
Liquid crystals (fluids that have certain crystalline properties) respond to an electric field by becoming cloudy or changing color. Effects of this kind can be used for the presentation of images...
Departments
50 and 100 Years Ago: April 1970
Science and the Citizen: April 1970
- Letters
Letters to the Editors, April 1970
- Recommended
Books
- Mathematical Recreation
Mathematical Games
- Amateur Scientist
The Amateur Scientist
- Departments
The Authors
Bibliography
