valve-preserving operations
1technology, history of — Introduction the development over time of systematic techniques for making and doing things. The term technology, a combination of the Greek technē, “art, craft,” with logos, “word, speech,” meant in Greece a discourse on the arts, both… …
2cardiovascular disease — Introduction any of the diseases, whether congenital or acquired, of the heart and blood vessels (blood vessel). Among the most important are atherosclerosis, rheumatic heart disease, and vascular inflammation. Cardiovascular diseases are a …
3Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
4Steam locomotive — A steam locomotive is a locomotive powered by steam. The term usually refers to its use on railways, but can also refer to a road locomotive such as a traction engine or steamroller.Steam locomotives dominated rail traction from the mid 19th… …
5Christmas tree (oil well) — Oil well Christmas tree In petroleum and natural gas extraction, a Christmas tree, or tree , (not wellhead as sometimes incorrectly referred to) is an assembly of valves, spools, and fittings used for an oil well, gas well, water injection well,… …
6India — /in dee euh/, n. 1. Hindi, Bharat. a republic in S Asia: a union comprising 25 states and 7 union territories; formerly a British colony; gained independence Aug. 15, 1947; became a republic within the Commonwealth of Nations Jan. 26, 1950.… …
7international relations — a branch of political science dealing with the relations between nations. [1970 75] * * * Study of the relations of states with each other and with international organizations and certain subnational entities (e.g., bureaucracies and political… …
8transplant — transplantable, adj. transplantation, n. transplanter, n. v. /trans plant , plahnt /; n. /trans plant , plahnt /, v.t. 1. to remove (a plant) from one place and plant it in another. 2. Surg. to transfer (an organ, tissue, etc.) from one part of… …
9Business and Industry Review — ▪ 1999 Introduction Overview Annual Average Rates of Growth of Manufacturing Output, 1980 97, Table Pattern of Output, 1994 97, Table Index Numbers of Production, Employment, and Productivity in Manufacturing Industries, Table (For Annual… …
10medicine, history of — Introduction the development of the prevention and treatment of disease from prehistoric and ancient times to the 20th century. Medicine and surgery before 1800 Primitive (primitive culture) medicine and folklore Unwritten history is not… …
