Comparative endocrinologists investigate the evolution of endocrine systems and the role of these sy.... hormon system

In addition, the isolation and purification of many mammalian hormones was made possible in large part by using other vertebrates as bioassay systems; that is, primitive animals have served as relatively simple, sensitive indicators of the amount of hormone activity in extracts prepared from mammalian endocrine glands. Finally, some vertebrate and invertebrate animals have provided model systems for research that have yielded valuable information on the nature of hormone receptors and the mechanisms of hormone action. ne of the most intensively studied systems for understanding hormone actions on target tissues has been the receptors for progesterone and estrogens (hormones secreted by the gonads) from the oviducts of chickens. The most primitive endocrine systems seem to be those of the type, in which the nervous system either secretes (hormones that act on, or are secreted by, nervous tissue) directly into the circulation or stores them in neurohemal organs (neurons whose ! endings directly contact blood vessels, allowing neurohormones to be secreted into the circulation), from which they are released in large amounts as needed. hormon system

Early developments, c. 650�490 . The 6th-century Greek poet Xenophanes, quoted by the historian Herodotus,.... silver gold

) produced a bimetallic system of pure gold and pure silver coins, but the foundation deposit of the Artemisium (temple to Artemis) at Ephesus shows that electrum coins were in production before Croesus, possibly under King Gyges. with its pegasi (from their constant obverse type of a pegasus) was coining silver from c. 575 with a light drachma of about three grams, and it is reasonably certain that in Athens, in the first half of the 6th century, Attic coins, based on a drachma of about 4.25 grams derived from Euboea and with a variety of obverse types, including an owl (the reverses, like those of the Corinthian pegasi, were impressed with a die design), were supplanting the earlier coinage of Aegina. These early silver coins, while much less valuable intrinsically than the electrum and gold coins of Asia Minor, nevertheless possessed considerable purchasing power: the Aeginetan and Attic-Euboic didrachms and the Corinthian tridrachm were high denominations suitable for ma! jor commerce and not for everyday life. From the Persian Empire, with its vast gold and silver coinage, successor to that of Croesus, to Magna Graecia and Sicily, and from the Dorian colony of Cyrene to the Greek or semi-Greek cities of Thrace, there was a network of varied and competitive currencies, generally of fine quality and steady weight. In certain cities of Italy and Sicily, however, including Tarentum and Metapontum, a different technique was popular, the obverse type in relief being repeated intaglio on the reverse, very probably with the object of concealing the older types of coins imported for restriking. Human or anthropomorphic figures, however, were comparatively rare on early Greek coins, though the famous gold darics, a name derived from Darius I, and silver shekels of Persia showed the great king in an attitude of attack. Much more popular was the representation of idealized heads of deities, which, once established for the two Athenas, Parthenos and Cha! linitis, at Athens and Corinth, quickly became the vogue elsew! here, encouraged by the development of double-relief coinage ( i.e., coinage with obverse and reverse in relief), which allowed the head of a civic deity to be paired on the other side by the city's symbol. silver gold

Many falconiforms pair for life; others, notably migran.... speci usual

The breeding pattern follows the usual sequence of nuptial display, nest building, incubation, fledging period, and postfledging period. The length of the breeding period varies from about 3 months in the smallest species to over 15 months in condors, crowned eagles, and probably harpy eagles. No species regularly produces two broods in a season, but second broods have been recorded, even in some large species. Most species perform several types of display, but species inhabiting woodland or forest display more often and more vociferously than related species of open country. All members of the family Accipitridae, as well as s, the osprey, and the secretary bird, construct nests, usually of sticks. The Cathartidae and the remaining Falconidae (forest falcons, falconets, and true falcons) do not make nests but use a hollow tree, another bird's nest, or a scrape on a ledge. Small species usually build a new nest annually; large species tend to return to and repair an old nest! . Falconiform eggs are rather large for the size of the birds and are usually rounded white or greenish ovals. The longest postfledging periods known are in and condors; in the crowned eagle the young remain dependent for 9 to 11 months, and this species normally breeds only every second year. speci usual

Aside from its rugged mountains and spectacular deep valleys, Yellowstone has unusual geologic features, including fossil .... hot yellowston

Its principal attractions, however, are its 10,000 hot springs, which find surface expression as steam vents, fumaroles, colourful hot pools, mud cauldrons, paint pots, hot springs and terraces, hot rivers, and geysers. Many of Yellowstone's noted hot springs and geysers are located in the western portion of the park between Old Faithful and Mammoth Hot Springs (the park's headquarters) some 50 miles (80 km) north. These include The Giantess, a geyser near Old Faithful with a six- to eight-month wait between eruptions; the Fountain Paint Pots in the Lower Geyser Basin, with pink, plopping mud geysers, fumaroles, and a blue, hot-spring pool; and Minerva, a multicoloured terrace with hot water cascades, at Mammoth Hot Springs. The Grand Canyon of the Yellowstone River is a colourful gorge 19 miles (30 km) long located in the north-central part of the park. The canyon, between 800 and 1,200 feet (240 and 370 metres) deep and up to 4,000 feet (1,200 metres) wide, has brilliantly! coloured rock walls, with two majestic waterfalls along its course; the Lower Falls of the Yellowstone River have a drop of 308 feet (94 metres). Smith, The Wolves of Yellowstone (1996), with over 70 color photos; and Thomas McNamee, The Return of the Wolf to Yellowstone (1997), discuss the reintroduction of wolves to the park. hot yellowston

Slit drums are found in Asia, the Americas, Africa, an.... slit drum

Large slit drums are sometimes less precisely called slit gongs. Slit drums are frequently ritual instruments that are regarded as possessing magical attributes and are often associated with water and with death and resurrection. Among the Aztecs (as the teponaztli ) and earlier Meso-American peoples, the slit drum was hollowed through an H-shaped slit, the two tongues of which produced different pitches; several instruments are believed to have been combined in order to play melodies. Two smaller, Chinese offshoots of the slit drum are the wood block and the wooden fish (Chinese mu y; also known as temple block), carved in the shape of a mythical fish and lacquered red. slit drum

In more advanced vertebrates the pronephros is the first kidney to develop in the embryo. Fre.... "pronephros." style:

MLA style: "pronephros." style: "pronephros." "pronephros." style:

Marshes are the usual habitat of muskrats, but they also live in wooded swamps, lakes, and streams,.... ) (

Marshes are the usual habitat of muskrats, but they also live in wooded swamps, lakes, and streams, where they build sizable lodges of cattails, sedges, and other vegetation. The Florida water rat ( Neofiber alleni ) is sometimes called the round-tailed muskrat. MLA style: "muskrat ( Ondatra zibethicus ) ." APA style: muskrat ( Ondatra zibethicus ) . style: "muskrat ( Ondatra zibethicus ) ." ) (

More than 100 species of unusual appearance are placed in .... mural egyptian

Other mormyrids have narrow heads, protruding lower lips, or short, rounded snouts. The Nile species of Mormyrus are represented in ancient Egyptian mural paintings and hieroglyphics. APA style: mormyrid. mural egyptian

The Florida manatee ( T. manatus latirostris ), which .... manate metr

manatus latirostris ), which is also found seasonally in the waters of nearby states, is one subspecies of the West Indian manatee ( T. Florida manatees generally grow to around 3 metres (10 feet) but range in length from about 2.5 to 3.9 metres (8 to 13 feet) and weigh up to 1,655 kg (3,650 pounds). West African manatees closely resemble West Indian manatees and are similar in size. Amazonian manatees are smaller, reaching a length of 2.8 metres (9.2 feet) and a weight of 480 kg (1,056 pounds), and, unlike the other two species, they are more blackish in colour, commonly have a white patch on the chest, and lack on the flippers. The manatee's large lips are prehensile and studded with specialized sensory bristles and hairs (vibrissae) for discriminating between and manipulating food plants. These traits, along with the manatee's ability to control the volume of small air spaces in the lungs, permit the animal to maintain a horizontal orientation anywhere in the water from t! he bottom to the surface. Although they can deposit large stores of fat, manatees' capacity to generate and retain body heat in cool water is poor. manate metr

The length of the lake approaches 65 mi (105 km), the width 4.... lake shore

The length of the lake approaches 65 mi (105 km), the width 40 mi; the surface of the lake is approximately 2,300 sq mi (about 6,000 sq km) in area in years when the water level is high, and about 1,600 sq mi (4,200 sq km) in area when the water level is low. The lake that formed in the depression originally drained into the Ma-ch'u Ho, but the rise of the basin's mountainous frame made this impossible. Melting waters from ancient glaciers thus accumulated and formed a big, deep lake in the late Pleistocene (at least 10,000 years ago). The depression in which the lake is set is a plain more than 10,500 ft high. In the south the depression is bordered by the Nan Koko Nor Shan (South Koko Nor Mountains), which form a narrow chain connecting with distinct peaks. The shores of the Koko Nor open out gently; the delta of the Pu-k'o Ho (Pu-k'o River) empties into the western part of the lake. Along the shores woods spread in terraces, the highest of which extends up over the lake t! o a height of 160 ft. On the eastern shore there are many small, isolated lakes and a rising, wooded shore area. Numerous sandy islands dot the lake; the largest has a length of 5,410 feet and a width of more than 1,000 feet. On the southwest shore of the lake and on the slopes of the Nan Koko Nor Shan there is an annual precipitation of 10 to 12 in. During the summer, water in the lake warms to 6468 F (1820 C). lake shore

The cycle of myths and stories surrounding al-Khi?r originated in a vague narrative in .... identifi musa

Musa questions what the man has done and receives a satisfactory explanation for everything; but by questioning, Musa forfeits the man's patronage. Arab commentators elaborated and embellished the Qur?anic story and named the man of God Khi?r, claiming that he turned green as he dived into the spring of life, though variant interpretations identify Khi?r with the vegetable world. Khi?r's immortality and ability to assume a variety of local characteristics probably account for his widespread popularity among Arabs, Turks, Iranians, and other Muslims, despite orthodox Islamic opposition. George, who, according to a local tradition, is of Syrian birth; in India and Pakistan, Khi?r is identified with a water deity (Khwadja Khi?r) specializing in the protection of mariners and river travelers; and, among the ?ufis, he is associated with their founders, who were often endowed with holiness and sainthood. identifi musa

plural Kappa, in Japanese folklore, a type of vampirelike lec.... spilled, lose

On the top of their head they have hollow indentations that are filled with water; if the water is spilled, they are said to lose their supernatural powers. spilled, lose

It is traversed east�west by the Al-Isma?iliyah Canal, formerly c.... canal, suez

It is traversed eastwest by the Al-Isma?iliyah Canal, formerly called the Sweet Water Canal, built 185863 from the Bulaq quarter of Cairo on the Nile to the city of Ismailia on Lake At-Timsa? to provide fresh water for the thousands of workmen building the Suez Canal. A branch, commencing just west of the city, runs south along the waterway to Suez city. Ancient ruins have been discovered at Tall al-Maskhutah, about 10 miles (16 km) west of Ismailia on the Al-Isma?iliyah Canal. The canal itself follows the course of an ancient Red SeaNile canal, first built by the Saite pharaoh Necho II (610595 ). canal, suez

The majority of cases of acute food poisoning are caused by bacteria such as , , Escherichia coli , and and their t.... (see (e.g.,

Instances of metal poisoning may sometimes be traced to the serving or preparation of acidic foods in certain cookware (see ; ). The more common poisonous plants and animals that cause food poisoning in humans include certain varieties of mussels and clams (see ); ocean and freshwater fish (see ); fungi (see ); plants (e.g., water hemlock, rhubarb greens); and nuts (e.g., akee nuts), seeds (e.g., tung seeds), and beans (e.g., fava beans). APA style: food poisoning. (see (e.g.,

There are numerous species of electric ray; most .... electr shock

There are numerous species of electric ray; most inhabit shallow water, but some ( Benthobatis ) live at depths of 1,000 m (3,300 feet) and more. The electric organs, composed of modified muscle tissue, are in the disk, one on each side of the head. Electric shocks emitted reach 220 volts and are strong enough to fell a human adult. APA style: electric ray. electr shock

in ceramics, a school of Turkish pottery making that flowered throughout the 16th and on into the 17th century. .... clai potteri

There may have been potteries at Iznik, where there were deposits of suitable clay, as early as the 12th century, but it was not until the late 15th century that pottery making came into its own in Turkey. Iznik ware was soft and sandy, being of grayish-white clay covered with a thin, usually white slip (a mixture of clay and water).

The , with elevations up to 15,653 feet (4,771 m), and the (up to 17,113 feet.... shore lake

The , with elevations up to 15,653 feet (4,771 m), and the (up to 17,113 feet [5,216 m]) frame the Issyk-Kul Basin with steep slopes and rocky crests. Air temperatures in July on the shore average about 62 F (17 C), while in January, on the western edge of the basin, the temperatures average about 28 F (-2 C). Lake Issyk-Kul's shores open out gently, with coves on the eastern and southeastern sides. More than 20 kinds of fish live in Lake Issyk-Kul. The lake's western and eastern shores serve as a wintering place for waterfowl. To conserve the wildlife, the Issyk-Kul Preserve was founded in 1948, encompassing a lake waterfront and a 1-mile (1.6-kilometre) shore zone in which hunting is forbidden. APA style: Issyk-Kul, Lake.

The Guianas are subdivided into three principal zones from.... guiana french

The Guianas are subdivided into three principal zones from south to north: the Precambrian , a region of low mountains that lies along the southern borders of the three states and rises to the region's highest point, , 9,094 feet (2,772 metres); a lower region of hilly country covered by a tropical hardwood forest and occasional savanna grasslands; and the low-lying, narrow alluvial plain along the Atlantic coast. The region's name derives from an Indian word for such lowlands: guiana (land of water). French, Dutch, and English are the official languages, respectively, of French Guiana, Suriname, and Guyana, but there are also many speakers of a language combining the three with African and Asian dialects. The earliest-known American Indians of the Guianas called the land Surinen , whence the name Suriname originated. Under the (1667), the Dutch received Suriname from England in exchange for Nieuw Amsterdam (New York), and the French were awarded French Guiana, setting the s! tage for the expulsion of Dutch settlers from Cayenne. French Guiana abolished slavery in 1848, and Dutch-ruled Suriname did the same in 1863. In British Guiana settlers discovered in 1879, thereby inaugurating the exploitation of mineral resources that have since become the dominant industries of Guyana and Suriname. was first discovered (1915) in Suriname and subsequently in British Guiana. French Guiana in 1946 became a French overseas d rtement , while Suriname underwent constitutional reform (194851) and was granted self-government by The Netherlands in 1954 and independence in 1975. guiana french

MLA style: "four-eyed fish." . . Chicago: , . APA style: four-eyed fish. ). . 2007 . Chicago: ..... style: four-ei

MLA style: "four-eyed fish." APA style: four-eyed fish.. style: four-ei

The majority of cases of acute food poisoning are caused by bacteria such as , , Escherichia coli , and and their toxi.... (see (e.g.,

Among the chemical poisons contaminating foods are certain heavy metals used in fungicides and insecticides (see ). Instances of metal poisoning may sometimes be traced to the serving or preparation of acidic foods in certain cookware (see ; ). The more common poisonous plants and animals that cause food poisoning in humans include certain varieties of mussels and clams (see ); ocean and freshwater fish (see ); fungi (see ); plants (e.g., water hemlock, rhubarb greens); and nuts (e.g., akee nuts), seeds (e.g., tung seeds), and beans (e.g., fava beans).

(species Felis viverrina ), tropical cat of the family Felidae, found in India and Southeast As.... cm black-ring

The adult animal stands about 40 cm (16 inches) at the shoulder, weighs 811 kg (1824 pounds), and is from 60 to 85 cm long, excluding the black-ringed tail, which accounts for an additional 2530 cm.

Long, cylindrical, scaleless, and usually gray-brown (.... electr prei

The tail region constitutes about four-fifths of the electric eel's total length, which is bordered along the underside by an undulating anal fin that is used to propel the fish. In one fish survey of a typical varzea, electric eels made up more than 70 percent of the fish biomass. The electric eel's penchant for shocking its prey may have evolved to protect its sensitive mouth from injury from struggling, often spiny, fish. Sometimes the electric eel does not bother to stun prey but simply gulps faster than the prey can react. style: "electric eel ( Electrophorus electricus ) ."fish links

also called Silver Salmon ( Onco rhyn chus kisutch ), species of salmon, family Salmonidae, prized for food and spo.... waters; pacif

Young coho stay in fresh water for about one year before entering North Pacific waters; they mature in about three years.

In astrology, Capricornus (also Capricorn) is the 10th sign of the zodiac, considered as governing the period c . December 2.... c period

In astrology, Capricornus (also Capricorn) is the 10th sign of the zodiac, considered as governing the period c . MLA style: "Capricornus." . .

Belugas are about 1.5 metres (4.9 feet) long at birth an.... beluga delphinapteru

Arctic populations of beluga whales are at home in pack ice but must migrate to warmer waters when the sea freezes over completely. The beluga population in the was nearly exterminated for its hides, and some other beluga populations are endangered by pollution. MLA style: "beluga ( Delphinapterus leucas ) ." APA style: beluga ( Delphinapterus leucas ) . style: "beluga ( Delphinapterus leucas ) ."

formerly Khadzhi-tarkhan, city and administrative cent.... km) mile

Astrakhan city is situated in the delta of the Volga River, 60 miles (100 km) from the Caspian Sea. Astrakhan was formerly the capital of a Tatar khanate, a remnant of the Golden Horde, located on the higher right bank of the Volga, 7 miles (11 km) from the present-day city. A city of bridges and water channels, it is an important river port, but because of the shallowness of the northern Caspian, seagoing craft have to transship about 125 miles (200 km) by road from Astrakhan, which is reached by a dredged channel.