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Adrenal Gland

2009-06-25T09:59:00.000-07:00

Adrenal Gland one of two small ductless glands located at the top of each kidney. The adrenal gland is functionally and histologically divided into two parts. The outher part, or cortex, produces an endocrine principle that is necessary for life. Cortical disease produces the syndrome of Addison's disease, which is fatal without treatment. The inner part, or the medulla, secretes the hormone epinephrine ( adrenalin ), which raises the blood pressure by stimulating the heart and contracting blood vessels. As part of the endocrine systemi the adrenal glands may exert their influence indirectly upon structures and functions for the most part controlled by other endocrine glands. The secretion of the adrenal medulla seems to have a protective or defensive function.

Abdomen

2009-02-10T02:35:00.000-08:00

Abdomen in man and other vertebrates the region of the body that lies between the thorax and the pelvis is called the abdomen. The abdominal cavity is separated from the thoracic cavity by the diaphragm and contains the viscera. It is lined by a serous membrane , the peritoneum. For convenience in locating ortangs and symptoms of disease , the abdomen is divided into mine regions : The upper regions are caşşed şeft hypochondriac , epigastric , and right hypochondriac ; the middle regions , left lumbar , umbilical , and right lumbar , and the lower , left inguinal , hypogastric , and right inguinal.

Abdominal pain is a symptom of many disorders and may originate outside as well as within the abdomen. Extra - abdominal causes of pain include disease of the chest , spine , or genitalia , poisoning , allergy , emotional upset , and disease of nerves. Within the abdomen pain my result from obstruction , inflammation , infection , disturbed function , or rupture. The treatment of abdominal pain varies with the cause.

In insects and other arthropoda , the abdomen is the posterior region of the body and is usually segmented.

Argus

2008-10-19T11:19:00.001-07:00

in Greek mythology, a fabulous creature with 100 eyes, of which only two slept at any one time. Hera placed him as guard over Io after she had been turned into a heifer. Hermes slew him after charming him to sleep with his music. Hera then changed him into a peacock with his eyes in the tail. In zoology, a genus of birds of the family Phasianidae and the subfamily Phasianinae. It contains the argus, or argus pheasant, Argusianus giganteus. The male measures between five and six feet from the tip of the bill to the extremity of the tail and is an eminently beautiful bird, the quill feathers of the wings, which often exceed three feet in length, being ornamented all along by a series of ocellated spots. The name Shetland argus is given to a starfish, Astrophylon scutatum. It is called also the basket urchin, or sea basket.

Argos

2008-10-19T11:16:00.000-07:00

Argos, a town in southern Argos and Corin-thia prefecture, northeastern Peloponnesus, Greece. Reputed to be the oldest city in Greece, it figured in Greek legends and in the 8th and 7th centuries B.C. dominated much of the Peloponnesus. It contains numerous ancient ruins. It was a center of worship of Hera.

Aneroid Barometer

2008-10-09T10:18:00.000-07:00

Aneroid Barometer, a barometer not containing a liquid and constructed on a totally different principle from that of the mercury barometer. Various forms of the instrument exist; one of these consists of a cylindrical metal box exhausted of air and having a lid of thin corrugated metal with a spring on the inside. An increase in atmospheric pressure forces the highly elastic lid inward; a decrease in pressure forces it outward. Delicate multiplying levers transmit these motions to an index, which moves on a scale and is graduated empirically by a mercurial barometer. The aneroid, being extremely delicate, is apt to get out of order, particularly when it has been exposed to great variations of pressure. When it is properly graduated , it is often used for determining the heights of mountains.

Anemone

2008-10-08T10:18:00.000-07:00

Anemone, a genus of plants belonging to the family Ranunculaceae (buttercups). It comprises approximately 120 species, most of which are perennial, are native to temperate and cold climates of the northern hemisphere, and bloom in early spring. Anemone coronaria, with tuberous roots, divided leaves, and large poppy-like blossoms of scarlet, blue, or white, is the well-known poppy anemone. Of about twenty species native to the U.S. and Canada, the most important are the wood anemone (Anemone quinquefolia), Anemone canadensis, Anemone hortensis, the garden anemone, and Anemone japonica, Japanese anemone. Anemones thrive in a well-drained, rich, loamy soil. Slight shade at midday and cool temperatures assure best growth.

Anemometer

2008-10-07T10:17:00.000-07:00

Anemometer, an instrument designed to measure the velocity of the wind. The first such instrument was invented by Wolfins in 1709. Three types of anemometers have been developed: those in which a windmill twists string around an axle against pressure, those in which a surface of definite dimensions is pressed against a spring, and those in which water or some other liquid is made to stand at a higher level in one leg of an inverted siphon than in the other. The anemometer most in use is of the first type, which was also the earliest type of the instrument. It has four light metallic hemispheres, called Robinson's cups (after Thomas Robinson who first employed them), which revolve like a vane or weathercock at the rate of exactly one-third the velocity of the wind. The result is recorded by a self-registering apparatus.

Analytical Chemistry

2008-10-06T09:54:00.000-07:00

Analytical Chemistry is an application of the principles of theoretical chemistry to the study of methods used for determining qualitatively the elements and compounds present in a substance of unknown composition and for determining quantitatively the percentage of each component in the unknown.

Analysis, a word meaning "separation into constituent parts," was first used in relation to chemical experiments by Robert Boyle (1627-1691). He distinguished between an element, a substance not decomposable by chemical means, and a compound. Although the analytical balance was not then available for precise mathematical treatment, he also performed quantitative experiments, searching for the amount of B and the amount of A in the unknown substance AB.

Qualitative analysis involves a preliminary examination using observation and simple tests followed by a schematic separation and the identification of the components. Following this analysis, a quantitative determination of the percentage of each component is performed by either chemical or physical methods. Chemical methods, both gravimetric and volumetric (titrimetric), are based on the mathematical relationship of reactants and products in a chemical reaction. These classical methods are supplemented but not replaced by the newer physical methods, which are based on the interaction of mass with energy. Among these methods are colorimetry, spectrophotometry, turbidimetry, nephelometry, fluorometry, x-ray spectrography, mass spectrography, x-ray diffraction, and polarography.
In academic and industrial laboratories the approach to an analytical problem is the same and is separated into these four steps: choice of method, sampling and preparation of unknown, determination, and evaluation of results. The trained analyst, in addition to a theoretical background in mathematics and chemistry, must have manual skill in laboratory techniques and familiarity with equipment.

Anaheim

2008-10-05T09:53:00.000-07:00

Anaheim, city, Orange Co., southern California, on a coastal plain, 23 miles southeast of Los Angeles. It lies in the heart of a rich fruit-growing valley, and its leading industries are the canning, packing, and processing of fruits and walnuts. Other manufactures are canning equipment, wire, and chemicals. Anaheim is near Disneyland, which is a 160-acre project conceived by Walt Disney. Disneyland includes an amusement center, a museum of Americana, and other facilities. Anaheim was founded in 1857 by German settlers as a cooperative community.

Anemias

2008-10-04T10:16:00.000-07:00

Anemia due to the faulty construction of red blood cells may occur in infections, chronic diseases (such as of the kidneys), and disorders of the spleen. Mechanical interference with the bone marrow results in anemia in such diseases as leukemia. Failure of blood formation may also be brought on by poisoning or irradiation injury.
The hemolytic anemias cover a wide variety of conditions in which the red blood cells are destroyed, a dramatic example being transfusion reactions from the use of incompatible blood. Chemical agents, including certain drugs; infections, such as malaria; vegetable and animal poisons, for example, snake venom; and various diseases, for example, Hodgkin's disease, are other important causes. Also in this category are congenital anemias in which the defect in the red blood cell is an inherited trait: congenital hemolytic jaundice, sickle-cell anemia, and Mediterranean anemia. Congenital hemolytic jaundice is successfully treated by splenectomy. For sickle-cellanemia and Mediterranean anemia, there is no known effective treatment.
The occurence of anemia secondary to acute blood loss is usually corrected by the transfusion of whole blood. The correction of anemia from chronic blood loss ultimately depends on correction of the underlying defect.

Anagram

2008-10-04T09:53:00.001-07:00

Anagram, a word or phrase formed by transposing and writing over again the letters of some other word or phrase. Strict anagrammatists do not admit a substitution or change in the letters to be transposed, but some famous anagrams do have these changes. Among the many famous anagrams are: "Honor est a Nilo" for Horatio Nelson and "I require love in a subject" for Queen Victoria's Jubilee Year. There are also interchangeable words, such as amor and Roma, Eros and rose, and evil and live. This old practice of anagrams is the foundation for a variety of games played by several persons.

Anacreon

2008-10-04T09:45:00.000-07:00

Anacreon , a renowned lyric poet of Greece, born at Teos in Ionia in the 6th century B.C. He enjoyed the patronage of Polycrates, tyrant of Sanios, and of Hipparchus at Athens. While at court, he composed most of the odes in praise of wine and women, which won for him pre-eminence among singers. A few of his authentic compositions have been preserved. More than 60 poems have been attributed to him, but they are probably imitations and the authorship is doubtful.

The Alamo

2008-10-02T05:57:00.000-07:00

a Franciscan mission in San Antonio, Tex., and the site of a gallant defense during the Texas war for independence. It was built about 1722 and consisted of a chapel, convent yard, convent and hospital building, and a plaza, all surrounded by a stout wall. After the disappearance of the Indians from the locality, the mission was abandoned, although after 1793 it was used occasionally as a fort. In 1836 it was occupied by a force of 150 Texans, commanded by Colonels William B. Travis and James Bowie. David Crockett fought here. Hoping for reinforcements, the garrison remained in the fort, despite the approach of the Mexican general Santa Ana and an army of over 4,000. When the Alamo was surrounded and hope of relief had faded, Travis and his men were faced with three alternatives: to surrender, make an attempt at an almost impossible escape, or resist.

Lucas Alaman

2008-10-01T05:51:00.000-07:00

Mexican historian and statesman, born in Guanajuato in 1792. When only 27 years of age he was sent as a delegate to the Spanish Cortes to plead the cause of Mexican independence. Under the Republic he served two terms as foreign minister and founded the Archivo General and the National Museum. His most important historical works were: Disertaciones sobre la historia de la Republica Mejicana, (5 vols., 1844) and Historia de Mejico desde la epoca colonial hasta nuestros dias, (5 vols., 1849-52). He died in 1853.

Alain Fournier

2008-09-29T05:48:00.000-07:00

Alain-Fournier,pseudonym of Henri Alain Fournier, a French author, born in La Chapelle-dAngillon, in 1886. He studied for the merchant marine, served for a short time in the army before World War I, and worked as a journalist. In 1913 he published The Wanderer, his only completed novel, and achieved widespread fame for this realistic study of adolescence. Fragments of the unfinished Colomhe Blanchet (1922) and Miracles (1924), stories and poems, were published after he was killed in action in 1914.

Alagoas

2008-09-28T05:34:00.000-07:00

Alagoas, a maritime state of northeastern Brazil bordering Pernambuco (north) and Sergipe (south). The chief products are sugar cane, cotton, manioc, corn, and rice; also timber and dyewoods.

El Alamein

2008-09-27T05:57:00.001-07:00

on the borders of Egypt and Cyrenaica, 60 miles west of Alexandria, was the site of the battle fought between German and Italian forces under Erwin Rommel and the British Eighth Army under Bernard Montgomery (Oct. 23-Nov. 4, 1942). Opposing forces were dug in on a front of 40 miles running from the sea at El Alamein south to the Qattara Depression. After a heavy artillery barrage, British infantry supported by armor attacked in the center and on the coast. On November 2 the enemy's defenses were smashed, and the triumphant advance to Tripoli began. The battle marked a turning point in World War II.

Alameda

2008-09-27T05:56:00.001-07:00

an island and city in San Francisco Bay, Alameda Co., California, 12 miles east of San Francisco. The city is connected with Oakland by several bridges and by a tunnel, called Posey Tube, completed in 1928. The major industries are shipyards and canneries. A naval air station, a Coast Guard base, and a maritime school are located here.

Alain de Lille

2008-09-27T05:48:00.001-07:00

Alain de Lille, in Latin Alanus ab Insulis, noted French scholastic philosopher, born in Lille about 1128. His aim was to combine rationalism with mysticism, and his basic principle was that, although reason can know the universe, a knowledge of God can be attained only by faith. He was the author of De planctu naturae and Anti-claudianus, and his great learning was admired by his contemporaries. He died in 1202.

Aladdin

2008-09-27T05:23:00.000-07:00

Aladdin in the story of "Aladdin and the Wonderful Lamp" in The Arabian Nights' Entertainment, the son of a poor widow. He possesses a magic lamp and ring, which enable him to command two powerful jinn. When he accidentally rubs the lamp, a jinni appears and builds him a palace and gives him riches and the princess of Cathay in marriage. His contest with the original owner of the lamp, a wicked magician, is told in the story.

Ague

2008-09-23T01:14:00.001-07:00

Ague an old name for malarial fever or any recurrent and severe symptom caused by malarial infection. It was also used to describe chills caused by other disease conditions

Aguascalientes

2008-09-23T01:14:00.000-07:00

Aguascalientes capital of the Mexican state of Aguascalientes, about 110 miles northeast of Guadalajara. The city maintains important Mexican railway shops. Its industries are chiefly processing industries but also include the production of sarapes and artistic leatherwork. Aguascalientes, founded in 1575, owes its name to its abundant thermal springs

Aguascalientes

2008-09-22T01:13:00.000-07:00

Aguascalientes small state in central Mexico, situated on the central plateau at about 6,000 feet. It is predominantly an agricultural region irrigated by the San Pedro, or Aguascalientes, River. Corn and chick peas are leading crops. There are large forested sections. The city of Aguascalientes is the capital. Area, 2,118 square miles.

Aguadilla

2008-09-21T01:13:00.000-07:00

Aguadilla, a seaport town of Puerto Rico, the largest community in the northwest corner of the island. It is situated on the Mona Passage, which connects the Atlantic Ocean with the Caribbean Sea. There is a small bay in which some fishing is done. The town has many well-paved roads and is on the main line of the coastal railroad. The Bor-inquen airfield is located 5 miles north of the town. The municipality of which Aguadilla is the administrative center is a fertile agricultural region furnishing coffee, tobacco, sugar, and fruit for export. The town has several large sugar refineries. Tradition has it that Christopher Columbus stopped in Aguadilla in 1493 to fill his water casks from the fountain that still flows in the town.

Agronomy

2008-09-20T01:12:00.000-07:00

Agronomy the science of soils and crops and their improvement. It has to do with crop rotation, field planning, and varieties of plants; insect, disease, and weed control; and planting, cultivation and harvest. The agronomist, in contrast with the animal husbandman, works with plant life. He seeks to produce better and more abundant forage and feed crops for livestock and improved strains of food and fiber plants and to develop better methods of soil treatment, tillage, and culture.