In zoology, the conversion of one type of living cell or group of cells into another as a means of regeneration. For example, the damaged or removed lens of a salamander eye is replaced through the transformation of nearby pigmented iris cells into lens cells. The regeneration of brain tissue from epidermis in annelid worms is another well-documented example of metaplasia.
Capital of Valencia province and the autonomous community (region) of Valencia, and of the former kingdom of Valencia, eastern Spain. Located on the Mediterranean coast at the mouth of the Río Turia (Guadalaviar), it is surrounded by orchards in a region known as the Huerta de Valencia. The earliest mention (Valentia) is by the Roman historian Livy, who states that the consul
Also spelled Al-ain principal town in al-Buraymi oasis, southeastern Abu Dhabi emirate, United Arab Emirates. The oasis town consists of houses of dried earth in a large palm grove; it also has a modern mosque and many gardens. Al-'Ayn is situated in a large expanse of fertile land at the foot of Jabal (mount) Hafit. Grave mounds at al-'Ayn have tombs with figures of animals and people carved from stone
Malayan wild cattle, a species of gaur (q.v.).
Chang settled in the Szechwan area and there studied the Tao (Way) sometime during the reign (125144) of Emperor Shun Ti of the Eastern Han dynasty. Later he composed a Taoist work to propagate his cult, which attracted many followers among both the Chinese and the indigenous ethnic
Formerly (until 1949) Madura, city, south-central Tamil Nadu state, southeastern India, bounded on the west by Kerala state. It is the second largest, and probably oldest, city in the state. Located on the Vaigai River and enclosed by the Anai, Naga, and Pasu (Elephant, Snake, and Cow) hills, the compact old city, site of the Pandya (4th11th century AD) capital, centres on Minaksi-Sundaresvara Temple. The temple, Tirumala Nayak
Alkaloids are found primarily in plants and are especially common in certain families of flowering plants. More
After youthful training as a chorister at Salamanca cathedral (c. 1484) and at the University of Salamanca (before 1490), Encina entered the service of the Duke of Alba as
As a young man, Ahmedi studied with the famous scholar Akmal ad-Din (al-Babarti) in Cairo. He then went to Kütahya, in Anatolia, and wrote for the ruler Amir Süleyman (136786). Later he went to the court of the Ottoman sultan Bayezid I (13891403), and, at the Battle of Ankara, in which the Ottomans suffered a drastic defeat,
French Aurigny one of the Channel Islands, in the English Channel, with an area of 3 square miles (8 square km), separated from the Normandy coast (Cap de la Hague) by the dangerously swift 10-mile (16-km) Race of Alderney. Swinge Race, on the west, separates it from the uninhabited Burhou, Ortac, and smaller islets, beyond which the notorious Casquets, a group of jagged rocks, carry a lighthouse. The nearest
Among the herons, plumages in patterns of blues, grays, and white are common; some, such as various egrets (see photograph), are all white. In storks, contrasting areas of black and white are characteristic. Some of the ibis are notable for the metallic sheen on the feathers. The hammerhead is of a sombre brown hue. The large bitterns and the tiger herons have cryptic
Earth, The global significance of gravity anomalies
The investigations of isostasy described above are statistical in approach in that they are directed toward determining depth of compensation and lithospheric thickness from large data sets without reference to individual geologic structures. On the other hand, the study of gravity is capable of extending the understanding of such major features of global
Inadequate secretion of parathyroid hormone, usually caused by accidental surgical removal of large amounts of parathyroid tissue (during thyroid surgery) or, less frequently, by defective action of the parathyroid gland. This deficiency results in low calcium and high phosphorus levels in the blood, often causing tetany (increased nervous and muscular excitability,
Born into a musical family, Atkins began playing the guitar as a child and during his teen years performed professionally as a fiddler. By the late 1940s he had become a sought-after
Also called Giulio Romano singer and composer whose songs greatly helped to establish and disseminate the new monodic music introduced in Italy about 1600. This is music in which an expressive melody is accompanied by evocative chords, as opposed to the traditional polyphonic style with its complex interweaving of several melodic
Cuneiform writing system used on the Syrian coast from the 15th to 13th century BC. It is believed that it was invented independent of other cuneiform writing systems and of the linear North Semitic alphabet, though similarities in certain letters suggest that it may have been patterned after the North Semitic alphabet. Unlike the North Semitic alphabet, however, Ugaritic
Nancy Mitford was one of six daughters (and one son) of the 2nd Baron Redesdale; the family name was actually Freeman-Mitford. The children were educated at home and were all highly original. Nancy's sister Unity (d. 1948) was notorious in Great Britain for her admiration of Adolf
Kindah was a Bedouin tribal kingdom quite unlike the organized states of Yemen; its kings exercised an influence over a number of associated tribes more by personal prestige than by coercive settled authority. Its area of influence was south central Arabia, from the Yemeni border nearly up to Mecca. The discovery of the tomb of a king of Kindah (datable to perhaps
Hood (of Whitley), Samuel Hood, 1st Viscount
Hood entered the navy in 1741, becoming a lieutenant in 1746. During the Seven Years' War he served in the English Channel and then the Mediterranean. In 1778, after further service in North America, he became commissioner of the dockyard at Portsmouth and governor of
Zirconium dioxide, an industrially important compound of zirconium and oxygen usually derived from the mineral zircon (see zirconium).
The Internet grew out of funding by the U.S. Advanced Research Projects Agency (ARPA), later renamed the Defense Advanced Research Projects Agency (DARPA), to develop a communication system among government and academic computer-research laboratories. The first network component, ARPANET, became operational in October 1969. With only 15 nongovernment (university) sites
The jack's effectiveness stems from the ratio of the load, or weight of the object
Viceroy and pasha of Egypt (180549), founder of the dynasty that ruled Egypt from the beginning of the 19th century to the middle of the 20th. He encouraged the emergence of the modern Egyptian state.
Beijing, The early empires
With but few interruptions, Beijing has been the capital of China for some eight centuries, and in number of years as the imperial capital it is exceeded only by Xi'an (Chang'an) in Shaanxi province and Luoyang in Henan province. In prehistoric times the area around Beijing was inhabited by some of the earliest-known human beings. Between 1918 and 1939 the fossil remains of Peking
Another Jewish Hellenistic work combining history and philosophy is The Fourth Book of Maccabees. The theme of the book, reflecting the views of the Greek Stoics, is whether the Inspired Reason is supreme ruler over the passions. This thesis is demonstrated by the martyrdom of the elderly scribe Eleazar and the unnamed seven brothers and their mother, taken from
Narrow passage of the eastern North Pacific through the northern Alexander Archipelago, southeastern Alaska, U.S. It extends for 150 miles (240 km) from the junction of Icy Strait and Lynn Canal, past Chichagof and Baranof islands (west) and Admiralty and Kuiu islands (east), to Coronation Island and the open sea. The deep, fault-formed strait, 310 miles (516 km) wide, is navigable and forms
The proximity of Africa has given Spain more African species than are found in the other Mediterranean peninsulas, while the Pyrenean barrier and the general extent of the country explain the number of indigenous species. The European wolf and the brown bear survive in the wildest areas of the northeast. The Barbary ape is possibly indigenous but more likely an
Also called Brissotin a label applied to a loose grouping of republican politicians, some of them originally from the département of the Gironde, who played a leading role in the Legislative Assembly from October 1791 to September 1792 during the French Revolution. Lawyers, intellectuals and journalists, the Girondins attracted a following of businessmen, merchants, industrialists, and financiers.