The Delivery of Medical Care in China
The main feature of the Chinese system is an integrated network of neighborhood stations that serve the functions of preventive medicine, primary medical care and referral to larger centers...
Features
Integrated Optics
Tiny lasers, lenses, prisms and switches made of thin films can manipulate light to serve the same purposes as the manipulation of electrons in the thin-film devices of integrated electronics...
The Embryo As a Transplant
Pregnancy can be regarded as a graft-host relationship, like that established by an organ transplant. It is an unusual one in that the embryo seems to be indifferent to the maternal immune response...
Wood Pulp
This major commodity consists of wood fibers separated mechanically, thermally or chemically. It is mainly used to make paper, but it is also the source of such chemical products as rayon and acetate film...
The Center of the Galaxy
Coded in the radio, infrared and X-ray emissions from the invisible nucleus of our galaxy is mounting evidence that It is periodically the scene of titanic explosions
Plate Tectonics and the History of Life in the Oceans
The breakup of the ancient supercontinent of Pangaea triggered a long-term evolutionary trend that has led to the unprecedented variety of the present biosphere
The Perception of Transparency
Certain mosaics of opaque colors and shapes give rise to the impression of transparency. A simple theoretical model predicts the conditions under which perceptual transparency will occur...
The Biological Control of Dung
When native Australian dung beetles cannot cope with the large, moist dung pads of cattle, dung covers pastureland and breeds insect pests. Now foreign beetles are being imported to help out...
Departments
50 and 100 Years Ago, April 1974
Science and the Citizen, April 1974
- Letters
Letters to the Editors, April 1974
- Recommended
Books, April 1974
- Mathematical Recreation
Mathematical Games, April 1974
- Amateur Scientist
The Amateur Scientist, April 1974
- Departments
The Authors, April 1974
Bibliography, April 1974
