ChicagoIllinoisCongresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Esophageal Motility Disorders: Disorders affecting the motor function of the UPPER ESOPHAGEAL SPHINCTER; LOWER ESOPHAGEAL SPHINCTER; the ESOPHAGUS body, or a combination of these parts. The failure of the sphincters to maintain a tonic pressure may result in gastric reflux of food and acid into the esophagus (GASTROESOPHAGEAL REFLUX). Other disorders include hypermotility (spastic disorders) and markedly increased amplitude in contraction (nutcracker esophagus).Ecotoxicology: The study of ENVIRONMENTAL POLLUTION and the toxic effects of ENVIRONMENTAL POLLUTANTS on the ECOSYSTEM. The term was coined by Truhaut in 1969.Aroclors: Industrial chemicals which have become widespread environmental pollutants. Each aroclor is a mixture of chlorinated biphenyls (1200 series) or chlorinated terphenyls (5400 series) or a combination of both (4400 series).Catholicism: The Christian faith, practice, or system of the Catholic Church, specifically the Roman Catholic, the Christian church that is characterized by a hierarchic structure of bishops and priests in which doctrinal and disciplinary authority are dependent upon apostolic succession, with the pope as head of the episcopal college. (From Webster, 3d ed; American Heritage Dictionary, 2d college ed)Grateful Med: A microcomputer-based software package providing a user-friendly interface to the MEDLARS system of the National Library of Medicine.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.