In physics, the passage of a particle through a seemingly impassable energy barrier. Though a particle's energy may be too low to surmount a barrier in classical physics, the particle may still cross the barrier as a consequence of its qua...

Any of a group of subatomic particles thought to be among the fundamental constituents of matter—more specifically, of protons and neutrons. The concept of the quark was first proposed by Murray Gell-Mann and George Zweig (b. 1937); ...

widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide (SiO2). Minor impurities such as lithium, sodium, potassium, and titanium may be present. Quartz has attracted attention from the earliest t...

France was the United States' first friend. The 1778 Treaty of Alliance between the two nations secured French military support in the American War for Independence. Yet just two decades later, the nations stood at the brink of a fo...

The quaternions are the second "number system" other than the real numbers ever discovered, and the first to be found by a deliberate search. Their immediate predecessor was the field of complex numbers, formed by adjoining an imaginary un...

As one of the founding nations of Canada, Québec felt that they have been mistreated and that the French language has been ignored by the rest of Canada. In 1968 René Lévesque, an ex-journalist, founded the first separatist p...

(born March 18, 1970, Newark, N.J., U.S.) American musician and actress, whose success in the late 1980s launched a wave of female rappers and helped redefine the traditionally male genre. She later became a notable film actress. Owens was...

Writer and filmmaker Quentin Tarantino's career "was a Hollywood dream story," according to Daniel Fierman in Entertainment Weekly: "a young video clerk from rough-and-tumble beginnings who wrote and directed a stylish, violence-packed fil...

QUESTS. The Ojibwa Indians tell the story of the boy Wunzh and his vision quest. Having reached the appropriate age for the ritual search for totem spirits, Wunzh is left alone in the great forest. After several days of fasting, he retires...

(from Nahuatl quetzalli, “tail feather of the quetzal bird [Pharomachrus mocinno],” and coatl, “snake”), the Feathered Serpent, one of the major deities of the ancient Mexican pantheon. Representations of a feathere...

QUIETISM. Although some of the important insights of Quietism—a movement distinguished from the generic sense of the word quietistic, which implies withdrawal or passivity with regard to politics or ethics—can be found in med...

Alkaloid found in the bark of cinchona trees and shrubs. The chemical structure of this heterocyclic compound is large and complex, with several rings. For the 300 years preceding the 1940s, when newer antimalarials were developed, quinine...

Any member of a class of cyclic organic compounds comprising a six-membered unsaturated ring (&see; saturation) to which two oxygen atoms are bonded as carbonyl groups (&singlehorzbond;C&doublehorzbond;O; &see; functional group). This stru...

Major Roman deity ranking close to Jupiter and Mars. The flamines (&see; flamen) of these three gods were the three major priests of Rome. Despite his importance, little is known about Quirinus, who was originally a god of the Sabines. He ...

In 1958, while television was still in its infancy, Americans were still innocent about the medium's predilection to sacrifice veracity in favor of entertainment. That year, a series of revelations about the fixing of television qui...

Products and quotients are the results obtained by applying the operations of multiplication and division, respectively, to particular mathematical objects. Both will be examined; products first, followed by quotients. Product is defined i...

(2002 est. pop. 62,000). Qurghonteppa is the fourth-largest city in the republic of Tajikistan in Central Asia and the administrative center of Khalton Province. The city is situated in the southwestern part of the country, in the Vakhsh R...

fl. 860-900 Arab translator and scientist who was instrumental in transmitting Greek ideas to the Muslim world, and thus later to the West. As an original thinker, Qusta discussed the uses of tangents and cotangents in trigonometry and wro...

Home Shopping Network (HSN) and Quality, Value, Convenience (QVC) were responsible for a historic change in American consumer habits, and have become as much a feature of television as religious channels. These two cable television channel...