Epidemiology

A set of statistical methods for analyzing the correlations among several variables in order to estimate the number of fundamental dimensions that underlie the observed data and to describe and measure those dimensions. It is used frequently in the development of scoring systems for rating scales and questionnaires.

Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.

Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.

A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.

Number of fetal deaths with stated or presumed gestation of 20 weeks or more in a given population. Late fetal mortality is death after of 28 weeks or more.

Experimentation on, or using the organs or tissues from, a human or other mammalian conceptus in the postembryonic period, after the major structures have been outlined. In humans, this corresponds to the period from the third month after fertilization until birth.

Materials used as reference points on or implanted in the body to position patients for radiotherapy.

Collections of related records treated as a unit; ordering of such files.

Use of a device (film badge) for measuring exposure of individuals to radiation. It is usually made of metal, plastic, or paper and loaded with one or more pieces of x-ray film.

A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)