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kymograph

medical instrument
Also known as: cymograph

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invention by Ludwig

  • Carl F.W. Ludwig, detail of an engraving
    In Carl F.W. Ludwig

    …a device known as a kymograph to record changes in arterial blood pressure; a simple stromuhr (1867), or flowmeter, to measure the rate of blood flow through arteries and veins; and a mercurial blood-gas pump for the separation of gases from the blood, which led to an understanding of the…

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  • adenosine triphosphate; physiology
    In physiology: Historical background

    In 1847 he invented the kymograph, a cylindrical drum used to record muscular motion, changes in blood pressure, and other physiological phenomena. He also made significant contributions to the physiology of circulation and urine secretion. His textbook of physiology, published in two volumes in 1852 and 1856, was the first…

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word processing, operation in which a text-editing software program called a word processor is used to create a document on a computer. A word-processing system can produce a wide variety of documents, including letters, memoranda, and manuals, rapidly and at relatively low cost.

The precursor of the modern word-processing system was developed in 1936. This device consisted of a kind of automatic typewriter, called an autotypist, that could store and reproduce simple documents. The autotypist used punched paper tape for its storage medium. In 1964 researchers at International Business Machines Corporation (IBM) produced the Selectric Typewriter, a relatively high-speed, automatic typewriter that had a magnetic tape data-storage unit and retrieval device. The development of electronic digital minicomputers and microcomputers during the late 1960s and ’70s gave rise to faster word-processing systems with greater capabilities.

A typical word-processing system consists of a printer that is linked to a computer. In many such systems the input terminal consists of an alphanumerical keyboard and a visual display. The display enables the keyboard operator to input and also check, edit, or revise the information to be entered. The text of the document, including all corrections, additions, and deletions made by the keyboard operator, is recorded by the computer. When the final draft is ready, the operator prints as many copies of the document as required. The information also can be stored by the computer for later retrieval.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Erik Gregersen.