Dioxin
Concern that this material is harmful to health or the environment may be misplaced. Although it is toxic to certain animals, evidence is lacking that it has any serious long-term effect on human beings...
Features
The T Cell and Its Receptor
The cell plays a key role in the body's capacity to fight viral infection, but it also acts to reject grafted tissue. Experiments have now identified the molecule that underlies this behavior...
Quantum Chemical Reactions in the Deep Cold
Quantum-mechanical effects allow some classically forbidden reactions to take place near absolute zero. This suggests that cold, dark clouds of galactic dust could contain seeds of life
Seismic Images of Plate Boundaries
By bouncing sound off rock layers under the sea floor and recording the reflections with many detectors, structural images of the crust can be made at the boundaries where plates collide and rift apart...
The Heart as an Endocrine Gland
It is more than a pump. The atria secrete a recently discovered hormone, atrial natriuretic factor, that interacts with other hormones to fine-tune control of blood pressure and volume
Reconstructing Bird Phylogeny by Comparing DNA's
Differences between DNA's reveal evolutionary distances between species, making it possible to reconstruct and date the branchings of avian lineages and providing a basis for classifying living groups...
Inca Stonemasonry
Enormous stone blocks were quarried, shaped and fitted so closely that a knife blade cannot be inserted into the joints. How was it done? To provide answers the author cut stones in an Inca quarry...
William Herschel and the Making of Modern Astronomy
He discovered thousands of stars and nebulas through telescopes that he himself built. His observations and theories expanded the bounds of astronomy to include the study of objects beyond the solar system...
Departments
50 and 100 Years Ago: February 1986
Science and the Citizen, February 1986
- Letters
Letters to the Editors, February 1986
- Recommended
Books, February 1986
- Amateur Scientist
The Amateur Scientist, February 1986
- Departments
The Authors, February 1986
Computer Recreations, February 1986
Bibliography, February 1986
