610 résultats pour "while"
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Antibiotics.
In some species of bacteria the cell wall consists primarily of a thick layer of peptidoglycan. Other species have a much thinner layer of peptidoglycan and an outer aswell as an inner membrane. When bacteria are subjected to Gram's stain, these differences in structure affect the differential staining of the bacteria with a dye calledgentian violet. The differences in staining coloration (gram-positive bacteria appear purple and gram-negative bacteria appear colorless or reddish, depending on t...
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Excerpt from Emma - anthology.
Her sister, though comparatively but little removed by matrimony, being settled in London, only sixteen miles off, was much beyond her daily reach; and many along October and November evening must be struggled through at Hartfield, before Christmas brought the next visit from Isabella and her husband and their littlechildren to fill the house and give her pleasant society again. Highbury, the large and populous village almost amounting to a town, to which Hartfield, in spite of its separate...
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Botswana - country.
at birth was 50.2 years, also a significant improvement. The urban population of Botswana has increased rapidly, from 18 percent of the total in 1981 to 51 percent in 2003. Gaborone, the capital, is the largest city and mainbusiness center. Other business centers are Francistown, Selebi-Pikwe, Molepolole, Kanye, and Serowe. Botswana received its name from the country’s principal ethnic group, the Tswana. Other ethnic groups include the Kgalagadi, Kalanga, and Basarwa. There are also asmall numbe...
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San Antonio (city, Texas) - geography.
The SBC Center is the home venue for the San Antonio Spurs of the National Basketball Association (NBA) and the San Antonio Silver Stars of the Women's NationalBasketball Association (WNBA). The dome also serves as the site for the Alamo Bowl, an annual post-season college football game. Large themed amusement parks inthe San Antonio area are Fiesta Texas and Sea World of Texas. San Antonio’s major annual event is the Fiesta, a ten-day celebration in late April with carnivals, ethnic feasts, art...
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brushing past me?
trying tofind theone onwhich shewas born, herfirst love, when shelast saw herparents, andIwas looking forAnna, too, Isearched andsearched, Igot apaper cutonmy forefinger andbled alittle flower ontothepage onwhich Ishould have seenherkissing somebody, butthis was allIsaw: I wanted tocry but Ididn't cry,Iprobably shouldhavecried, Ishould havedrowned usthere inthe room, ended our suffering, theywould havefound usfloating face-down intwo thousand whitepages, orburied underthesalt ofmy evaporated tea...
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Helicopter.
naturally flaps down so as to increase lift. Flapping allows the differences in lift caused by uneven rotor tip speed to cancel out, producing a stable ride. Many helicoptersuse mechanical hinges with lubricated bearings, but some use flexible straps made of a composite material in order to reduce the required maintenance. Helicopters require different amounts of lift and thrust at different times during flight, because the aerodynamic forces acting on them change during hovering andacceleration...
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Guatemala - country.
C Climate The climate of Guatemala varies according to elevation, from hot coastal plains to cold mountain heights. Most of the population lives between 900 and 2,400 m (3,000and 8,000 ft) above sea level, where there are warm days and cool nights with average annual temperatures of 20°C (68°F). The coastal regions are hot and humid,with average annual temperatures of 28°C (83°F). A rainy season, from May through October, is sometimes called “winter” because it brings cloudy afternoons andlower...
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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...
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Benjamin Harrison (1833-1901).
homesteaders against pressure from the powerful railroads. He fought vigorously for Civil War veterans, supported high taxes on imports (called tariffs), payments todisabled and opposed the Chinese Exclusion Act, which stopped Chinese immigration to the U.S. for 10 years ( see Immigration: From 1840 to 1900 ). He also introduced 101 special pension and relief bills in six years. Harrison's name was well known by the Republican National Convention in 1884. In spite of this, Congressman and forme...
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Benjamin Harrison (1833-1901) - Histoire
homesteaders against pressure from the powerful railroads. He fought vigorously for Civil War veterans, supported high taxes on imports (called tariffs), payments todisabled and opposed the Chinese Exclusion Act, which stopped Chinese immigration to the U.S. for 10 years ( see Immigration: From 1840 to 1900 ). He also introduced 101 special pension and relief bills in six years. Harrison's name was well known by the Republican National Convention in 1884. In spite of this, Congressman and forme...
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Mesopotamian Art and Architecture
I
INTRODUCTION
Mesopotamian Art and Architecture, the arts and buildings of the ancient Middle Eastern civilizations that developed in the area (now Iraq) between the Tigris and
Euphrates rivers from prehistory to the 6th century
BC.
arts. III EARLY DYNASTIC PERIOD Figures from Tell AsmarCreated around 2700 bc, these stone figures are from the city of Tell Asmar in what today is Iraq. From the Temple ofAbu, the statuettes stood in watchful prayer with the wide, staring eyes often found in Sumerian sculpture. The figuresare in the Iraq Museum, Baghdād, Iraq.Art Resource, NY The first historical epoch of Sumerian dominance lasted from about 3000 BC until about 2340 BC. While earlier architectural traditions continued, a ne...
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Sewage Disposal.
greater load on the piping system and the treatment plant. The amount of storm-water drainage to be carried away depends on the amount of rainfall as well as on the runoff or yield of the watershed ( see Drainage). A typical metropolitan area discharges a volume of wastewater equal to about 60 to 80 percent of its total daily water requirements, the rest being used for washingcars and watering lawns, and for manufacturing processes such as food canning and bottling. B Composition The composi...
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Sigmund Freud.
reminiscences from the past and about her daydreams. Remarkably, as her narrative revisited memories from the past, which were associated with the onset of aparticular symptom, each symptom disappeared when accompanied by an emotional outburst. Breuer made use of this discovery to eliminate her symptoms one at atime. He called the treatment the cathartic technique (from the Greek katharsis meaning “purgation”). The treatment was time consuming and required considerable effort to reach dimly re...
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Jimmy Carter.
B Election of 1976 Carter apparently decided as early as 1972, halfway through his four-year term as governor, that he would seek the presidency of the United States. Soon after the1972 election, his campaign manager drew up a detailed campaign strategy. Carter followed the plan closely, beginning an exhausting schedule of campaigning as soonas his gubernatorial term ended. When Carter formally announced in January 1975 that he was a candidate for president, he had almost no national reputation...
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Jimmy Carter
B Election of 1976 Carter apparently decided as early as 1972, halfway through his four-year term as governor, that he would seek the presidency of the United States. Soon after the1972 election, his campaign manager drew up a detailed campaign strategy. Carter followed the plan closely, beginning an exhausting schedule of campaigning as soonas his gubernatorial term ended. When Carter formally announced in January 1975 that he was a candidate for president, he had almost no national reputation...
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Native American Languages.
From Nahuatl, spoken in Middle America, come avocado, cacao, cocoa, chile/chili, chocolate, coyote, tamale , tomato , and many others. Contributions from South American languages include jaguar, cashew, tapioca, and toucan from Tupinambá; alpaca, condor, jerky, llama, puma, and quinine from Quechua; and barbecue, canoe, guava, hammock, hurricane, iguana, maize, papaya, and potato from Maipurean (Arawakan). Native American languages, in turn, have borrowed words from European language...
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Burundi - country.
D Way of Life Most Burundians live in self-contained compounds of small round grass huts scattered over the country’s many hills. The rugo , the traditional Tutsi hut, is divided into sections and surrounded by an enclosure and cattle corrals. Families farm scattered plots of land on different soils at different altitudes to minimize crop failure. Thefloors of valleys are avoided due to higher temperatures and tsetse fly infestation. Social roles are largely determined by ethnicity, with the T...
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Aztec Empire.
tribute to the empire in agricultural products, which were used to finance public projects. All able-bodied men owed military service to the empire. Citizens could also bedrafted to work on public lands or build temples, dikes, aqueducts, and roads. Although Aztec society had strict classes, a person’s status could change based on his or her contribution to society. Commoners could improve their rank, especially byperforming well in battle, and become prosperous landowners. Young people of some...
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Aztec Empire - USA History.
tribute to the empire in agricultural products, which were used to finance public projects. All able-bodied men owed military service to the empire. Citizens could also bedrafted to work on public lands or build temples, dikes, aqueducts, and roads. Although Aztec society had strict classes, a person’s status could change based on his or her contribution to society. Commoners could improve their rank, especially byperforming well in battle, and become prosperous landowners. Young people of some...
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The Souls of Black Folk by W.
in amused contempt and pity. One ever feels his two-ness,—an American, a Negro; two souls, two thoughts, two unreconciled strivings; two warring ideals in onedark body, whose dogged strength alone keeps it from being torn asunder. The history of the American Negro is the history of this strife—this longing to attain self-conscious manhood, to merge his double self into a better and truer self. Inthis merging he wishes neither of the older selves to be lost. He would not Africanize America, f...
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Roman Mythology.
Her temple on the Aventine Hill in Rome was a center for organizations of skilled craftspeople. According to tradition, in 509 BC the dynasty of Etruscan kings ended and the Roman Republic was founded. The republic was ruled by two chief magistrates, called consuls, who were elected by the people to one-year terms. During the time of the republic, the Capitoline temple became the most important public shrine of theRoman people and the focus of public worship. Each January, the new consuls offer...
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Virus (life science) - biology.
RNA into DNA earned them their name because this process is the reverse of the usual transfer of genetic information, from DNA to RNA.) The DNA form of theretrovirus genome is then integrated into the cellular DNA and is referred to as the provirus. The viral genome is replicated every time the host cell replicates its DNA and is thus passed on to daughter cells. Hepatitis B virus can also transcribe RNA to DNA, but this virus packages the DNA version of its genome into virus particles. Unlike...
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China - country.
North China lies between the Mongolian Steppe on the north and the Yangtze River Basin on the south. It stretches west from the Bo Hai gulf and the Yellow Sea to theeastern edge of the Tibetan Plateau. Administratively, North China includes Beijing and Tianjin municipalities; Shandong and Shanxi provinces; most of Hebei, Henan,and Shaanxi provinces; and portions of Ningxia Hui Autonomous Region and of Jiangsu, Anhui, and Gansu provinces. Humans have lived in the agriculturally rich region of Nor...
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Georgia (state) - geography.
B Rivers and Lakes Most of the rivers of Georgia drain eastward to the Atlantic Ocean proper or southward to the Gulf of Mexico. Only a few flow northward to the Tennessee River, which isa major tributary of the Mississippi River. Most of the rivers flowing to the coasts are navigable by barges and small craft as far upstream as the Fall Line. The major river flowing to the Atlantic is the Savannah River, which, with the Tugaloo River, one of its headwaters, forms most of the state’s eastern bo...
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Georgia (state) - USA History.
B Rivers and Lakes Most of the rivers of Georgia drain eastward to the Atlantic Ocean proper or southward to the Gulf of Mexico. Only a few flow northward to the Tennessee River, which isa major tributary of the Mississippi River. Most of the rivers flowing to the coasts are navigable by barges and small craft as far upstream as the Fall Line. The major river flowing to the Atlantic is the Savannah River, which, with the Tugaloo River, one of its headwaters, forms most of the state’s eastern bo...
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Coral Reef.
sensitive to particles of mud or sediment settling on them, which means that corals rarely grow close to rivers or other sources of sediment. In the sea, light is filteredout by depth, so reef-building corals can only grow in relatively shallow water. Even in the clearest oceans few reef-building corals grow below a depth of 80 to 100 m(260 to 328 ft). Although corals need nutrients, they cannot thrive in areas where there are large amounts of nutrients. Typically, microscopic organisms in the p...
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Social Psychology.
During the 1960s, American psychologist Stanley Milgram studied a form of social influence stronger than conformity: obedience to authority. In a famous series ofexperiments that attracted controversy about human research ethics, Milgram put each of 1,000 subjects into a situation in which they were ordered by anexperimenter to administer painful electric shocks to a confederate (who did not actually receive any shocks). The subjects in these studies were led to believe that theywere acting as '...
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Dolphin (aquatic mammal) - biology.
Scientists have observed dolphins displaying three types of caregiving behaviors: standing by, excitement, and supporting. In standing-by behavior, dolphins remain inthe vicinity of an injured or ill companion without offering aid. In excitement behavior, dolphins swim swiftly in circles around an injured dolphin, responding aggressivelytoward threats to the injured animal. For instance, they may bite harpoon lines or charge boats that come too close to the animal. In supporting behavior, one or...
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France - country.
In both the Paris and Aquitaine basins, fertile soils derived from limestone and wind-deposited dust, called loess, have supported prosperous agriculture since ancienttimes. Other lowlands in France are scattered and relatively small. They include the Alsace Plain in the east, bordering Germany, the valley of the Rhône River in thesoutheast, and the Languedoc Plain along the Mediterranean coast. A2 Uplands France contains several regions of uplands, the worn down remains of ancient mountain sys...
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Apollo Program - astronomy.
Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...
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Apollo Program - U.
Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...
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Pablo Picasso.
Color juxtapositions—between blue and orange, for instance—are intentionally strident and unharmonious. The representation of space is fragmented and discontinuous. While the left side of the canvas is largely Iberian-influenced, the right side is inspired by African masks, especially in its striped patterns and oval forms. Suchborrowings, which led to great simplification, distortion, and visual incongruities, were considered extremely daring in 1907. The head of the figure at the bottom right,...
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Native Americans of Middle and South America.
A line that snakes across central Mexico near the Tropic of Cancer forms the northern boundary of Mesoamerica; north of this line rainfall sharply declines and theclimate is much drier. The ancient civilizations of Mesoamerica all arose and developed in the area between this line and the Guatemalan highlands far to the south. Richvolcanic soils are found throughout much of the region. A2 People and Languages Mesoamerica was a great melting pot, home to many peoples and interrelated cultures. In...
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Massachusetts - geography.
mi). Other large artificial lakes include Wachusett Reservoir, East Brimfield Reservoir, and Cobble Mountain Reservoir. Assawompsett Pond, covering about 10 sq km(about 4 sq mi), is the largest natural lake. North Watuppa Pond and Long Pond are other large natural lakes. Lake Chaubunagungamaug, near Webster, is usuallycalled Webster Lake, because the Algonquian name is difficult to pronounce and spell. The full version of the Native American name is said to be the longest place-namein North Amer...
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Ear.
I
INTRODUCTION
Ear, organ of hearing and balance. Only vertebrates, or animals
line or rotates in any direction. Each canal also contains sensory areas with sensory hair cells that project into a cone-shaped cap of gelatin. Two of the semicircularcanals are in a vertical position and are used to detect vertical movement, such as jumping or falling. The third canal is horizontal and detects horizontal movement,such as turning or spinning. The action of the canals depends on the inertia of the fluid inside. When the motion of the body changes, the fluid lags behind, causing...
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Winston Churchill
I
INTRODUCTION
Winston Churchill (1874-1965), British politician and prime minister of the United Kingdom (1940-1945, 1951-1955), widely regarded as the greatest British leader of
the 20th century.
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Winston Churchill.
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Winston Churchill .
sufficient tools to break the stalemate on the western front and he worked on developing armored fighting vehicles (tanks) to break the deadlock and end theslaughter. As the lines hardened on the western front, Churchill focused on a campaign to force open the Dardanelles Strait, controlled by the Ottoman Empire, to give the Allies adirect route to Russia through the Black Sea. Such a move would bring much-needed supplies to the Russian armies and eliminate the Ottomans from the war. Whenthe nav...
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Canada.
Six general landform regions are distinguishable in Canada: the Appalachian Region, the Great Lakes and St. Lawrence Lowlands, the Canadian Shield, the Great Plains,the Canadian Cordillera, and the Canadian Arctic Archipelago. B1 Appalachian Region and Great Lakes and St. Lawrence Lowlands Eastern Canada consists of the Appalachian Region and the Great Lakes and St. Lawrence Lowlands. The Appalachian Region embraces Newfoundland Island, NovaScotia, New Brunswick, Prince Edward Island, and the G...
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Canada - country.
Six general landform regions are distinguishable in Canada: the Appalachian Region, the Great Lakes and St. Lawrence Lowlands, the Canadian Shield, the Great Plains,the Canadian Cordillera, and the Canadian Arctic Archipelago. B1 Appalachian Region and Great Lakes and St. Lawrence Lowlands Eastern Canada consists of the Appalachian Region and the Great Lakes and St. Lawrence Lowlands. The Appalachian Region embraces Newfoundland Island, NovaScotia, New Brunswick, Prince Edward Island, and the G...
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Canada - Canadian History.
Six general landform regions are distinguishable in Canada: the Appalachian Region, the Great Lakes and St. Lawrence Lowlands, the Canadian Shield, the Great Plains,the Canadian Cordillera, and the Canadian Arctic Archipelago. B1 Appalachian Region and Great Lakes and St. Lawrence Lowlands Eastern Canada consists of the Appalachian Region and the Great Lakes and St. Lawrence Lowlands. The Appalachian Region embraces Newfoundland Island, NovaScotia, New Brunswick, Prince Edward Island, and the G...
- Midnighters
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Nanotechnology.
ever-finer method of reducing material to the nanoscale size. Instead, nanostructures would be assembled atom by atom and molecule by molecule, from the atomiclevel up, just as occurs in nature. However, assembly at this scale has its own challenges. In school, children learn about some of these challenges when they study the random Brownian motion seen in particles suspended in liquids such as water. Theparticles themselves are not moving. Rather, the water molecules that surround the particles...
- Lifehack
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Public Education in the United States.
opportunities for them to break out from whatever social or economic circumstances constrained their development. IV HIGHER EDUCATION During the 20th century participation in higher or postsecondary education in the United States increased as dramatically as it did in American high schools. At thebeginning of the century about 2 percent of Americans from the ages of 18 to 24 were enrolled in a college. There were fewer than 1,000 colleges then, with enrollmenttotaling about 157,000 students. N...
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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...
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Earthquake.
III CAUSES Most earthquakes are caused by the sudden slip along geologic faults. The faults slip because of movement of the Earth’s tectonic plates. This concept is called theelastic rebound theory. The rocky tectonic plates move very slowly, floating on top of a weaker rocky layer. As the plates collide with each other or slide past eachother, pressure builds up within the rocky crust. Earthquakes occur when pressure within the crust increases slowly over hundreds of years and finally exceeds...
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Radio.
signal, such as a musical note. This form of modulation, AM, is used in many radiotelephony services including standard radiobroadcasts. AM is also employed for carriercurrent telephony, in which the modulated carrier is transmitted by wire, and in the transmission of still pictures by wire or radio. See Broadcasting, Radio and Television. In FM the frequency of the carrier wave is varied within a fixed range at a rate corresponding to the frequency of a sound signal. This form of modulation, p...
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- On the road
- The Alchimist