The 10-year trend in many parts of the world toward the legalization of induced abortion has led to new studies of the practice, more open release of data, better medical procedures and lower mortality rates
Within a few years much of the cropland in the U.S. will be planted without a moldboard plow. In most conditions planting without tillage (but with herbicides) can save labor, energy, water and soil
Black holes are often defined as areas from which nothing, not even light, can escape. There is good reason to believe, however, that particles can get out of them by "tunneling"
When an antigen, or foreign substance, combines with an antibody molecule, it does so at a site that fits it precisely as a lock fits a key. The nature of this site has been worked out in considerable detail
Highly specialized nerve circuits enable the human visual system to separate information about the direction in which an object is moving from the details of the object's pattern
They are electrons emitted by a fresh metal surface. Such surfaces are created by wear or by the cracking associated with metal fatigue; thus exoelectrons have become useful in the study of those processes
The age of space exploration has shown that craters such as those on the moon are a feature of all the bodies in the inner solar system. Cratering is therefore one of the main keys to the system's history
Once the inhabitants of a rich and powerful kingdom, these followers of Moses now constitute perhaps the world's smallest ethnic minority. The forces that keep them isolated have also helped them to survive