National Institute on Aging (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. Through basic and clinical biomedical research and training, it conducts and supports research into the nature of the aging process and diseases associated with the later stages of life. The Institute was established in 1974.National Institute on Drug Abuse (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. It supports a comprehensive research portfolio that focuses on the biological, social, behavioral and neuroscientific bases of drug abuse on the body and brain as well as its causes, prevention, and treatment. NIDA, NIAAA, and NIMH were created as coequal institutes within the Alcohol, Drug Abuse and Mental Health Administration in 1974. It was established within the NATIONAL INSTITUTES OF HEALTH in 1992.National Institutes of Health (U.S.): An operating division of the US Department of Health and Human Services. It is concerned with the overall planning, promoting, and administering of programs pertaining to health and medical research. Until 1995, it was an agency of the United States PUBLIC HEALTH SERVICE.National Institute on Alcohol Abuse and Alcoholism (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. It conducts research focused on improving the treatment and prevention of alcoholism and alcohol-related problems to reduce the health, social, and economic consequences of this disease. NIAAA, NIMH, and NIDA were created as coequal institutes within the Alcohol, Drug Abuse and Mental Health Administration in 1974. It was established within the NATIONAL INSTITUTES OF HEALTH in 1992.Rehabilitation: Restoration of human functions to the maximum degree possible in a person or persons suffering from disease or injury.Community Integration: Policies and programs which ensure that DISPLACED PERSONS and chronic illnesses receive the support and SOCIAL SERVICES needed to live in their communities.Academies and Institutes: Organizations representing specialized fields which are accepted as authoritative; may be non-governmental, university or an independent research organization, e.g., National Academy of Sciences, Brookings Institution, etc.National Institute on Deafness and Other Communication Disorders (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. It conducts and supports biomedical research and research training on normal mechanisms as well as diseases and disorders of hearing, balance, smell, taste, voice, speech, and language. It was established in 1988.United StatesResearch: Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. (Webster, 3d ed)Physics: The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Diagnostic Techniques, Neurological: Methods and procedures for the diagnosis of diseases of the nervous system, central and peripheral, or demonstration of neurologic function or dysfunction.Climate Change: Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.Gravity Sensing: Process whereby a cell, bodily structure, or organism (animal or plant) receives or detects a gravity stimulus. Gravity sensing plays an important role in the directional growth and development of an organism (GRAVITROPISM).United States National Aeronautics and Space Administration: An independent Federal agency established in 1958. It conducts research for the solution of problems of flight within and outside the Earth's atmosphere and develops, constructs, tests, and operates aeronautical and space vehicles. (From U.S. Government Manual, 1993)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Specific Gravity: The ratio of the density of a material to the density of some standard material, such as water or air, at a specified temperature.Gravity, Altered: A change in, or manipulation of, gravitational force. This may be a natural or artificial effect.Climate: The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Gravitation: Acceleration produced by the mutual attraction of two masses, and of magnitude inversely proportional to the square of the distance between the two centers of mass. It is also the force imparted by the earth, moon, or a planet to an object near its surface. (From NASA Thesaurus, 1988)Esophageal Sphincter, Lower: The physiologic or functional barrier to GASTROESOPHAGEAL REFLUX at the esophagogastric junction. Sphincteric muscles remain tonically contracted during the resting state and form the high-pressure zone separating the lumen of the ESOPHAGUS from that of the STOMACH. (Haubrich et al, Bockus Gastroenterology, 5th ed., pp399, 415)Esophageal Sphincter, Upper: The structure at the pharyngoesophageal junction consisting chiefly of the CRICOPHARYNGEUS MUSCLE. It normally occludes the lumen of the ESOPHAGUS, except during SWALLOWING.Manometry: Measurement of the pressure or tension of liquids or gases with a manometer.Esophagogastric Junction: The area covering the terminal portion of ESOPHAGUS and the beginning of STOMACH at the cardiac orifice.Esophagus: The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.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).Peristalsis: A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction.Deglutition: The act of taking solids and liquids into the GASTROINTESTINAL TRACT through the mouth and throat.Pressure: A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Esophageal Achalasia: A motility disorder of the ESOPHAGUS in which the LOWER ESOPHAGEAL SPHINCTER (near the CARDIA) fails to relax resulting in functional obstruction of the esophagus, and DYSPHAGIA. Achalasia is characterized by a grossly contorted and dilated esophagus (megaesophagus).