You are currently logged out. Please sign in to download the issue PDF.
How much oil does the U.S. have left? Clues are yielded by computer simulation of the results of drilling for oil at random, but decisions on energy policy call for a thoroughgoing inventory of the resource
They are the smallest known agents of infectious disease: short strands of RNA. They cause several plant diseases and possibly are implicated in enigmatic diseases of man and other animals
Mechanical substitutes for the natural heart are steadily getting better. In time they will be ready for human beings needing them, a development with social implications as well as medical ones
The large spiral galaxy nearest our own, it has been a laboratory for the study of the evolution of stars and galaxies. Even today it presents puzzles; for example, how are its spiral arms arrayed?
Modern plant-breeding practices have reduced the genetic variability of the cultivated wheats. The best hope for future crop improvements lies in exploiting the abundant gene pool of the plant's wild relatives
Could calculating machines have pains, Martians have expectations and disembodied spirits have thoughts? The modern functionalist approach to psychology raises the logical possibility that they could
They are mostly fluid, given form by a network of polymer strands. A balance of forces maintains this state of affairs; disturbing it infinitesimally can bring on a phase transition and collapse the gel
As Alexander Graham Bell was developing the telephone Elisha Gray was doing the same. Bell got the patent, but the episode is nonetheless an instructive example of simultaneous invention