135 résultats pour "pattern"

• Light - astronomy.

  Each different frequency or wavelength of visible light causes our eye to see a slightly different color. The longest wavelength we can see is deep red at about 700 nm.The shortest wavelength humans can detect is deep blue or violet at about 400 nm. Most light sources do not radiate monochromatic light. What we call white light,such as light from the Sun, is a mixture of all the colors in the visible spectrum, with some represented more strongly than others. Human eyes respond best to greenlight...

• Light I INTRODUCTION Light, form of energy visible to the human eye that is radiated by moving charged particles.

  simulates the action of a moving charge upon the electric field. It creates a wave that travels along the rope in a direction that is perpendicular to the initial up anddown movement. Because electromagnetic waves are transverse—that is, the vibration that creates them is perpendicular to the direction in which they travel, they are similar to waveson a rope or waves traveling on the surface of water. Unlike these waves, however, which require a rope or water, light does not need a medium, or su...

• Confucian philosophy, Korean

  neglected by more traditional Confucianism. Read with new eyes, an entirely new level of meaning was uncovered in the ancient texts: they discovered a Confucian foundation for the meditative cultivation of consciousness that had been a particular strength of the Buddhists, and to frame it and provide an account of sagehood equal to Buddhist talk of enlightenment, they found a complete metaphysical system, a Confucian version of the kind of thinking that had been elaborated mainly under Daoist au...

• Islamic Art and Architecture I INTRODUCTION Córdoba Mosque Courtyard This mosque and courtyard with its repeated horseshoe arches was built between the 8th and 10th centuries in Córdoba, Spain.

  Süleymaniye MosqueThe Süleymaniye Mosque in İstanbul was built in 1550. The architect, Sinan, based his design on Byzantine churches, inparticular the Hagia Sophia. The large central dome above a square opens to smaller spaces vaulted by buttressing half-domes. The four tapering minarets with balconies are characteristic of the architectural style of later Islamic mosques.Gian Berto Vanni/Art Resource, NY The few and relatively simple rituals of the Islamic faith gave rise to a unique religious...

• Global Warming.

  some of the warming influence of increasing greenhouse gases. A1 Carbon Dioxide Carbon dioxide is the second most abundant greenhouse gas, after water vapor. Carbon dioxide constantly circulates in the environment through a variety of naturalprocesses known as the carbon cycle. It is released into the atmosphere from natural processes such as eruptions of volcanoes; the respiration of animals, whichbreathe in oxygen and exhale carbon dioxide; and the burning or decay of plants and other organic...

• House (architecture) I INTRODUCTION Trulli in Alberobello, Italy Alberobello, in the Apulia region of southeastern Italy, is noted for its unusual limestone houses known as trulli (from Greek trullos, dome).

  Fresco in the Villa of the Mysteries, PompeiiThe Villa of the Mysteries, Pompeii, Italy (built about 50 bc), featured a large hall with this mural encircling it. The mural ispainted in the Second Style of Roman painting. (Historians of art recognize four periods or styles in Roman wall painting.)The mural in the Villa of the Mysteries is thought to depict the initiation rituals of a mystery religion. For this reason, it hasbeen conjectured that the hall was used for cult rituals.Bridgeman Art Li...

• Evolution - biology.

  genetic diversity to extinction. Sexual reproduction ensures that the genes in a population are rearranged in each generation, a process termed recombination. Although the combinations of genes inindividuals change with each new generation, the gene frequency, or ratio of different alleles in the entire population, remains relatively constant if no evolutionaryforces act on the population. One such force is the introduction of new genes into the genetic material of the population, or gene pool...

• Animal Courtship and Mating - biology.

  activity. These animals frequently copulate in water, and the penis helps transfer sperm before it is carried away by the currents Ostriches and rheas also contain apenis within the cloaca. Virtually all snakes and lizards display yet another variation of internal fertilization. Located in the tail are two penises, called hemepenes, which are covered by spinesand knobs that help lock it into place during mating. The male uses one hemepene at a time for copulation. Male salamanders secrete large...

• Black Death.

  disappeared in the West. V DISAPPEARANCE OF PLAGUE Plague became less common in Europe after the 1530s. The last plague in England was in 1665, the last in Western Europe in 1722. Numerous theories have beenoffered to explain the disappearance of plague. It has been argued that black rats, the primary carriers of plague, may have been replaced by larger brown rats that donot carry the infection. A second theory suggests that increased immunity among the rodents that carried the disease or chang...

• Black Death .

  disappeared in the West. V DISAPPEARANCE OF PLAGUE Plague became less common in Europe after the 1530s. The last plague in England was in 1665, the last in Western Europe in 1722. Numerous theories have beenoffered to explain the disappearance of plague. It has been argued that black rats, the primary carriers of plague, may have been replaced by larger brown rats that donot carry the infection. A second theory suggests that increased immunity among the rodents that carried the disease or chang...

• Confucius

  official to several of the highest positions in the land. Nor does the story end there. By the time of the Han dynasty (206 BC-AD 220), Confucius was celebrated as the ‘uncrowned king' of the state of Lu, and by the fourth century AD, any prefecture wanting to define itself as a political entity was required by imperial decree to erect a temple to Confucius. Gods in China are local cultural heroes who are remembered by history as having contributed meaning and value to the tradition, and of...

• Depression (psychology).

  IV CAUSES Some depressions seem to come out of the blue, even when things are going well. Others seem to have an obvious cause: a marital conflict, financial difficulty, or somepersonal failure. Yet many people with these problems do not become deeply depressed. Most psychologists believe depression results from an interaction betweenstressful life events and a person’s biological and psychological vulnerabilities. A Biological Factors Depression runs in families. By studying twins, researche...

• Police.

  body. In larger agencies, executive officers may be selected through a civil service or merit system, after moving through the ranks from patrol officer to sergeant,lieutenant, captain, and (in still larger agencies) deputy or assistant chief. At the county level, the head of the agency usually holds the title sheriff. The sheriff is almost always elected and has the power to appoint deputies. Sheriffs'departments often provide law enforcement services for unincorporated areas of counties and ar...

• Assyria - USA History.

  villages and cities were ransacked and razed, but no attempt was made to annex their territories. In the course of time this pattern of conquest changed, and the Assyrian rulers began to make Assyria the center of a new empire by incorporating the conquered landsinto their domain, although probably not according to a conscious plan. Toward the end of the 10th century BC, for example, Adad-nirari II annexed the Aramaean state centering on Nisibis, east of the Habur River. His son, Tukulti-Ninurt...

• Rome (Italy) - geography.

  country’s best, and in the summer at the Baths of Caracalla. The city also has some 20 theaters and 6 major concert halls, which offer a varied repertory during the fall,winter, and spring. The museums of the city deal with all aspects of the arts and sciences and are among the world’s finest. The oldest art collection in Rome, housed in the CapitolineMuseum, was established in 1471 and contains exceptional antiquities. Among other Roman museums are the National Museum of the Villa Giulia, which...

• Invertebrate - biology.

  animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...

• Invertebrate - biology.

  animals with a five-pointed design. They live in the sea and move with the help of tiny fluid-filled feet—another feature found nowhere else in the animal world. Zoologists recognize several different groups of worms. The phylum known as flatworms contains the simplest animals possessing heads. Nerves and sense organs areconcentrated in the head. Most flatworms are paper-thin and live in a variety of wet or damp habitats, including the digestive systems of other animals. Roundwormsrepresent anot...

• Book Publishing I INTRODUCTION Book Publishing, manufacture, publication, and distribution of books.

  they use advanced printers and binding techniques to run off as many books as required. Printing only as many books as needed allows companies to save money, andbeing able to store books digitally means that books can be printed whenever necessary, keeping them in print indefinitely. B Marketing and Distribution Once the book has been made, it is ready for distribution. Traditionally, trade books have been sold primarily by salespeople calling on bookstores across the countryand taking orders f...

• Jerusalem - geography.

  There are many other artifacts in the city, tied to various periods of history; those of Canaanite, Israelite, Greek, Roman, Arab, Crusader, and Ottoman origin areamong the more prominent. Modern attractions include the Israel Museum (completed in 1965), which houses the Shrine of the Book, where the Dead Sea Scrolls areexhibited; the Rockefeller Museum (opened in 1938), which contains archaeological finds; the Yad Vashem Holocaust Museum; the Museum of Biblical Archaeology; theMuseum of Islamic...

• Snake (reptile).

  in their heads that conduct sound. They are able to hear low-frequency sounds and to sense vibrations that travel through the ground or water. The majority of snakeshave good eyesight, especially for detecting moving objects, although most burrowing snakes can only distinguish between light and dark. Pit vipers, boas, and pythons have an unusual adaptation for detecting warm-blooded prey and predators. On the heads of these snakes are small pits lined with cellsthat are extremely sensitive to he...

• Arctic - Geography.

  The Arctic is not a frozen desert devoid of life on land or sea, even during the cold, dark winter months. Spring brings a phenomenal resurgence of plant and animal life.Low temperatures are not always the critical element—moisture, the type of soil, and available solar energy are also extremely important. Some animals adapt well toArctic conditions; for instance, a number of species of mammals and birds carry additional insulation, such as fat, in cold months. Arctic summers with extended dayli...

• Mythology.

  Across cultures, mythologies tend to describe similar characters. A common character is the trickster. The trickster is recklessly bold and even immoral, but through hisinventiveness he often helps human beings. In Greek mythology, Hermes (best known as the messenger of the gods) was a famous trickster. In one version of acharacteristic tale, Hermes, while still an infant, stole the cattle of his half-brother Apollo. To avoid leaving a trail that could be followed, Hermes made shoes from thebark...

• Slovakia - country.

  The country is divided informally into the three regions of Western Slovakia, Central Slovakia, and Eastern Slovakia, corresponding to administrative divisions that wereabolished in 1989. Most of Slovakia’s 600,000 Hungarians live in the southern parts of Western and Central Slovakia, which served as the cultural center of Hungary forseveral centuries after Hungary proper was invaded by the Ottomans in the 16th century. The Ruthenian and Ukrainian minorities are concentrated in the northernregio...

• Theater I INTRODUCTION The Art of Theater BBC Worldwide Americas, Inc.

  Theater at EpidaurusAncient Greek dramas were performed in open-air theaters like this one in Epidaurus, Greece, which was designed byPolyclitus the Younger in 350 bc. A festival of ancient Greek drama is still held in the summer in this 14,000-seat theater.Roger Wood/Corbis Fundamental to the theater experience is the act of seeing and being seen; in fact, the word theater comes from the Greek word theatron , meaning 'seeing place.' Throughout the history of world cultures, actors have used...

• Kenya - country.

  threatens fish and other water life in the lake by depriving them of oxygen. Kenya is well known for its game parks—including Masai Mara Game Park and Tsavo National Park in the south, and Marsabit National Reserve in the north—whichattract large numbers of tourists and much revenue. Conservation of wildlife within reserves has thus received high priority. About 13 percent (2007) of Kenya’s totalland is protected. There are 229 (2004) threatened species in Kenya. Threatened habitats include the...

• Los Angeles - geography.

  (2006 population, 472,494), located east of the Port of Los Angeles. The city of Compton (95,701) is located north of Long Beach, on the east side of the AlamedaCorridor. On the other side of the corridor are the cities of Torrance (142,350) and Inglewood (114,914). Northwest of Inglewood and west of downtown Los Angeles are the wealthy and fashionable Santa Monica (88,050) and Beverly Hills (34,979). Both cities are enclaves:Santa Monica is surrounded by the City of Los Angeles to the north, ea...

• Los Angeles - geography.

  (2006 population, 472,494), located east of the Port of Los Angeles. The city of Compton (95,701) is located north of Long Beach, on the east side of the AlamedaCorridor. On the other side of the corridor are the cities of Torrance (142,350) and Inglewood (114,914). Northwest of Inglewood and west of downtown Los Angeles are the wealthy and fashionable Santa Monica (88,050) and Beverly Hills (34,979). Both cities are enclaves:Santa Monica is surrounded by the City of Los Angeles to the north, ea...

• Kentucky - geography.

  The climate of Kentucky is characterized by warm or hot summers and cool winters. Throughout the year, temperatures do not vary greatly from place to place,although they are generally slightly lower in the Appalachian Plateaus region than elsewhere in the state. Average July temperatures are usually from 24° to 27°C (76°to 80°F) in the central and western areas and from 23° to 24°C (74° to 76°F) in the east. January averages range from below 1°C (34°F) in the northern Bluegrassregion to more tha...

• Kentucky - USA History.

  The climate of Kentucky is characterized by warm or hot summers and cool winters. Throughout the year, temperatures do not vary greatly from place to place,although they are generally slightly lower in the Appalachian Plateaus region than elsewhere in the state. Average July temperatures are usually from 24° to 27°C (76°to 80°F) in the central and western areas and from 23° to 24°C (74° to 76°F) in the east. January averages range from below 1°C (34°F) in the northern Bluegrassregion to more tha...

• Nevada - geography.

  The Truckee, Carson, and Walker rivers flow out of the Sierra Nevada, thread their way around several of the desert ranges, and also end in closed basins. The Walkerflows into Walker Lake, the Carson into Lahontan Reservoir. The major part of the Truckee’s flow is now diverted to Lahontan Reservoir, although as required by lawsome of it empties into Pyramid Lake. Because these three streams flow constantly, the lakes into which they empty never dry up. Winnemucca Lake formerly receivedoverflow w...

• Nevada - USA History.

  The Truckee, Carson, and Walker rivers flow out of the Sierra Nevada, thread their way around several of the desert ranges, and also end in closed basins. The Walkerflows into Walker Lake, the Carson into Lahontan Reservoir. The major part of the Truckee’s flow is now diverted to Lahontan Reservoir, although as required by lawsome of it empties into Pyramid Lake. Because these three streams flow constantly, the lakes into which they empty never dry up. Winnemucca Lake formerly receivedoverflow w...

• Atom I INTRODUCTION Water Molecule A water molecule consists of an oxygen atom and two hydrogen atoms, which are attached at an angle of 105°.

  spontaneously break apart and change, or decay, into other atoms. Unlike electrons, which are fundamental particles, protons and neutrons are made up of other, smaller particles called quarks. Physicists know of six different quarks.Neutrons and protons are made up of up quarks and down quarks —two of the six different kinds of quarks. The fanciful names of quarks have nothing to do with their properties; the names are simply labels to distinguish one quark from another. Quarks are unique amo...

• Midnighters

• Africa.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• Africa - Geography.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...