joint In geology, a brittle fracture surface in rocks along which little or no displacement has occurred. Present in nearly all surface rocks, joints extend in various directions, generally more vertical than horizontal. Joints may have smooth, clean surfaces, or they may be scarred by slick- ensides, or striations. Jointing does not extend very far into the Earth’s crust, because at about 7.5 mi (12 km) even rigid rocks tend to flow plas¬ tically in response to stress.
joint Structure connecting two or more bones. Most joints, including
synovial (fluid-containing) joints and those between vertebrae, which incorporate a disk, can move. Immovable joints include the sutures of the skull (see fontanel). Ligaments connect the bones of a joint, but muscles keep them in place. Joint dis¬ orders include various forms of arthritis, injuries (e.g., sprains, frac¬ tures, and DISLOCATIONS), CONGENITAL disorders, and vitamin deficiencies. See illustration above.
joints and joinery In architec¬ ture, the connection of construction materials. All joints are carefully detailed by the architect with concern for strength, movement, penetration by the elements, and incompatibili¬ ties. The term joinery refers espe¬ cially to carpentry. Common types of
acetabulum
fibrous capsule
cavity of joint
synovial
membranes
cartilage
head of femur
ligament of head of femur
synovial membranes
transverse ligament of acetabulum
fibrous capsule
zona orbicularis
Section through a hip joint. The hip joint, a synovial joint, is of the ball-and-socket type, the head of the femur articulating with the cup-shaped acetabulum. The joint cavity is enclosed by a fibrous capsule lined with a type of connective tissue (syn¬ ovial membrane) that produces a fluid (synovial fluid) which lubricates the cartilage-covered opposing surfaces of bone. The fibrous capsule is made up of internal circular fibres (zona orbicularis) and external longitudinal fibres, strength¬ ened by ligaments, and covered by muscles.
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joints include the dovetail, used for interlocking two flat members at right angles, as in the sides of a drawer; the doweled joint, in which doweling is employed for mechanical strength; and the mortise and tenon, in which a projecting piece fits into a groove, used to join a horizontal member with the vertical member of a frame. See illustration on following page.
Joinville \zhwa n -'vel\, Jean, sire de (b. c. 1224, Joinville, Champagne—d. Dec. 24, 1317, Joinville) French chronicler. A member of the lesser nobility of Champagne, Joinville became friends with Louis IX while taking part in the Seventh Crusade (1248-54). His famous His- toire de Saint Louis, completed c. 1309, is a prose chronicle that provides a supreme account of that Crusade, including vivid descriptions of the financial hardships, the dangers of sea voyages, the ravages of disease, the confusion and lack of discipline in the Crusading army, and Muslim customs. On his return he was made seneschal of Champagne and divided his time between the royal court and his fief of Joinville.
Joliba River See Niger River
Joliot-Curie \zh6l-y6-km-'re\, (Jean-) Frederic orig. Jean- Frederic Joliot (b. March 19, 1900, Paris, France—d. Aug. 14, 1958, Arcouest) French physical chemist. In 1926 he married Irene Curie (1900- 58), daughter of Pierre and Marie Curie; he would eventually append her name to his. In 1932 he first observed production of an electron-positron pair. Frederic and Irene are remembered for their discovery of new radio¬ active isotopes prepared artificially, for which they were jointly awarded a 1935 Nobel Prize. Frederic served in the Resistance during World War II and became a member of the Communist Party; in the postwar years he served as the highest government official in the realm of atomic energy but was dismissed for his political beliefs. From 1946 to 1956 Irene directed the Radium Institute, where she had first worked in 1918; Frederic succeeded her in the post. Both died of conditions caused by their long exposure to radioactivity.
Jolliet \zh6l-'ya\, Louis (b. before Sept. 21, 1645, probably Beaupre, near Quebec—d. after May 1700, Quebec province) French Canadian explorer and cartographer. He led an expedition in the Great Lakes region in 1669. In 1672 he was commissioned by the governor of New France to explore the Mississippi in the company of Jacques Marquette and five others. In 1673 the party set out in birchbark canoes across Lake Michi¬ gan, following the Fox and Wisconsin rivers to the Mississippi, then down the Mississippi to its confluence with the Arkansas. They concluded that the river flowed south to the Gulf of Mexico and not, as hoped, into the Pacific Ocean. After their return, Jolliet explored areas of Hudson Bay and the Labrador coast.
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996 I Jolson ► Jones, D.
Some common woodworking joints. The dado joint is made by inserting the end of one piece into a rectangular groove (dado) in another. The rabbet joint involves joining pieces along a channel or notch (rabbet) along an edge of one or both members. The miter joint is formed by butting two ends cut at an angle. The finger joint is used to lengthen a board by interlacing fingerlike projections. The mortise- and-tenon joint is made by inserting a projection (tenon) on one piece into a notch or hole (mortise) in the other. The dovetail joint consists of one or more fan-shaped tenons fitting tightly into corresponding mortises.
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Jolson, Al orig. Asa Yoelson (b. May 26, 1886, Srednike, Russia—d. Oct. 23, 1950, San Francisco, Calif., U.S.) Russian-born U.S. singer, song¬ writer, and blackface comedian. Jolson’s family arrived in the U.S. in 1893 and settled in Washington, D.C., where Jolson made his first stage appearance in 1899, performing in vaudeville before joining a minstrel troupe (see minstrel show) in 1909. In New York City he was featured in musicals such as La Belle Paree (1911), Honeymoon Express (1913), and Big Boy (1925). In Sinbad (1918) he transformed the unsuccessful George Gershwin song “Swanee” into his trademark number. In Bombo (1921) he introduced “My Mammy,” “Toot, Toot, Tootsie,” and “California, Here I Come.” In 1927 he starred in The Jazz Singer, the first feature film with synchronized speech as well as music and sound effects. His later films include The Singing Fool (1928), Mammy (1930), and Swanee River
(1940).
Jomini ^zho-mo-'neV, (Antoine-) Henri, baron de (b. March 6, 1779, Payeme, Switz.—d. March 24, 1869, Passey, France) Swiss-French general and military theorist. After a volunteer stint with the French army (1798-1800), he wrote his Treatise on Grand Military Operations, 5 vol. (1805). He was appointed staff colonel in 1805 by Napoleon I, who had read his book. He was created a baron after the Treaties of Tilsit (1807). He rose to the post of chief of staff, but unjust treatment by his superiors prompted him to resign (1813), and thereafter he fought for France’s enemy, Russia. Of his numerous later works on military history and strat¬ egy, the best known are Principles of Strategy (1818) and Summary of the Art of War (1838). He was the first to fix divisions between strategy, tac¬ tics, and logistics, and his systematic attempt to define the principles of warfare made him a founder of modern military thought.
Jomon \'j6-,man\ culture (c. 7500-c. 250 bc) Mesolithic culture char¬ acterized by pottery decorated with cord patterns (jomon). Jomon artifacts
have been found from Hokkaido to the Ryukyu Islands. The Jomon people lived in sunken pit dwellings and subsisted primarily by hunting, fishing, and gathering. They used chipped-stone and later polished-stone tools and made clothing of bark. Though their pottery was technically primitive, it demonstrated diverse forms and imaginative designs and decorations. Many contemporary Ainu believe themselves to be descended from the Jomon people. See also Yayoi culture.