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Possible definitions for quanta
quantum
In physics, a discrete natural unit, or packet, of energy, charge, angular momentum, or other physical property. Light, for example, which appears in some respects as a continuous electromagnetic wave, on the submicroscopic level is emitted and absorbed in discrete amounts, or quanta; for light of a given wavelength, the magnitude of all the quanta emitted or absorbed is the same in both energy and momentum. These particlelike packets of light are called photons, a term also applicable to quanta of other forms of electromagnetic energy such as X rays and gamma rays. Submicroscopic mechanical vibrations in the layers of atoms comprising crystals also give up or take on energy and momentum in quanta called phonons. See also quantum mechanics.
Luanda
City (pop., 1995 est.: 2,081,000), capital of Angola. Situated on the Atlantic coast, it is Angola's largest city and its second busiest seaport. Founded in 1576 by Paulo Dias de Novais, it became the administrative center for the colony of Angola in 1627. It was a major outlet for slave traffic to Brazil until the 19th cent. Many Mbundu live in the city, and there is a sizable Cuban community. It is a commercial and industrial area, with oil-refining capacity. It is the seat of the Univ. of Luanda; the old fortress of Sã o Miguel lies beyond the port.
plantain
Any of about 265 species of familiar garden, lawn, and roadside weeds in the genus Plantago of the family Plantaginaceae. Distinctively, the leaves lack a proper blade. What appears to be a blade is an expanded petiole (leafstalk), with several parallel main veins, emerging at the base of the stalk. Small flowers are borne in spikes or heads atop long leafless stalks. The greater plantain (P. major) provides seed spikes for bird food. Ribwort, or English, plantain (P. lanceolata) and hoary plantain (P. media) are troublesome weeds. Some species have been useful in medicine (e.g., as an ingredient in laxatives).
Tall plant (Musa paradisiaca) of the banana family that is closely related to the common banana (M. sapientum). Believed to have originated in S.E. Asia, the plantain grows 10-33 ft (3-10 m) tall and has a conical false "trunk" formed by the leaf sheaths of its spirally arranged, long, thin leaves. The green-colored fruit is larger than that of the banana and contains more starch. Because the starch is maximal before the fruit ripens, the fruit is not eaten raw but is boiled or fried, often with coconut juice or sugar as flavoring. It may also be dried for later use in cooking or ground for use as meal, which can be further refined to a flour. The plantain is a staple food and beer-making crop for E. African peoples, and is also eaten in the Caribbean and Latin America.
quartz
Second most abundant mineral (after feldspar) in the earth's crust, present in many rocks. Quartz, which consists of silica, or silicon dioxide (SiO2), has great economic ...
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