The Biological Effects of Low-Level Ionizing Radiation
What is the hazard to human beings of ubiquitous low-level radiation from natural and artificial sources? The evidence so far indicates that compared with other hazards it is slight
Volume 246, Issue 2
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Features
The Fossil Footprints of Laetoli
At this site in Tanzania thousands of animal tracks, including those of predecessors of man, are found in volcanic ash that fell some 3.5 million years ago
How an Animal Virus Gets into and out of Its Host Cell
Experiments with the Semliki Forest virus show in considerable detail how the cell is caused to manufacture new virus particles, including an outer membrane that is a piece of the cell's own
Titan
The largest moon of Saturn is the only moon in the solar system with a substantial atmosphere. The chemistry of the atmosphere may resemble that of the earth's atmosphere before life arose
The Chemistry of Flames
Research in the field of combustion chemistry focuses mainly on the intermediate substances created as hydrocarbon fuels burn to produce carbon dioxide, water and trace pollutants
Quasars as Probes of the Distant and Early Universe
The light from most of these enigmatic objects was emitted 15 billion years ago. Therefore they are a unique clue to how the universe looked when it was only a fourth its present age
Color Vision in Fishes
The visual environments of fishes are blue, green or near infrared. The retinal pigments acquired by diverse fish species in adapting to these environments are a valuable clue to the evolution of the eye
Henry A. Rowland
This 19th-century American physicist has been undervalued by history. Among his accomplishments was the building of the first engine for ruling the diffraction gratings on which modern spectroscopy depends