The Structure of the U.S. Economy
The input-output tables on the next seven pages divide the economy into 81 sectors and list the transactions among them. The numbers are the constants of the technological relations among the sectors
Features
The Control of Biochemical Reactions
The cell is a factory and enzymes are its machines. Two feedback systems control production, one regulating synthesis of enzymes, another their activity. Models of the two systems are described
Attitude and Pupil Size
Dilation and constriction of the pupils reflect not only changes in light intensity but also ongoing mental activity. The response is a measure of interest, emotion, thought processes and attitudes
Intense Magnetic Fields
Continuous fields as strong as 250,000 gauss, 500,000 times the strength of the earth's magnetic field, have been generated at the National Magnet Laboratory
An Early Neolithic Village in Greece
Excavations at Nea Nikomedeia in northern Greece have uncovered a community of 8,000 years ago. Its remains suggest that agriculture and animal husbandry came to Europe earlier than has been supposed
Moths and Ultrasound
Certain moths can hear the ultrasonic cries by which bats locate their prey. The news is sent from ear to central nervous system by only two fibers. These can be tapped and the message decoded
The Discovery of Icarus
A chunk of rock less than a mile in diameter, Icarus comes closer to the sun and the earth than any other asteroid whose orbit has been accurately computed. It should miss us by four million miles in 1968
The Stirling Refrigeration Cycle
In 1816 Robert Stirling invented an engine that operated by heating and cooling air in a closed cycle. The cycle has now been "reversed" in an efficient machine for cooling things to very low temperatures
Departments
50 and 100 Years Ago: April 1965
Science and the Citizen: April 1965
- Letters
Letters to the Editors, April 1965
- Recommended
Books
- Mathematical Recreation
Mathematical Games
- Amateur Scientist
The Amateur Scientist
- Departments
The Authors
Bibliography
