62 résultats pour "vessel"
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Ship.
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INTRODUCTION
Ship, vessel that is buoyant in the water and used
B1 Biremes Experience soon proved that longer ships posed a new set of problems: They were weaker structurally, more difficult to maneuver, and presented a larger target to anyenemy ship with a ram. In the 8th century BC Mediterranean shipbuilders eliminated these problems with the bireme , a war galley built to accommodate two levels, or banks , of oarsmen. Oarsmen on the lower level rowed oars from ports cut into the side of the vessel, while those above rowed from the deck. This arrangemen...
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Stroke.
IV DIAGNOSIS The symptoms typical of a stroke can also be caused by other conditions, including brain tumors, various infections, and overdoses of certain drugs. A patient that hasstrokelike symptoms may undergo a battery of imaging techniques to rule out other medical problems and confirm that a stroke has occurred. The key imagingtechnique used in diagnosing strokes is computed tomography (also known as CT or CAT scanning), which employs X rays to obtain images of the internal structures oft...
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Circulatory System.
C Additional Functions In addition to oxygen, the circulatory system also transports nutrients derived from digested food to the body. These nutrients enter the bloodstream by passingthrough the walls of the intestine. The nutrients are absorbed through a network of capillaries and veins that drain the intestines, called the hepatic portal circulation.The hepatic portal circulation carries the nutrients to the liver for further metabolic processing. The liver stores a variety of substances, suc...
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Sailing.
the sails sweep across the decks of the vessel from one side to the other, and also because of the danger of breaking spars. In wild jibing, control can be lostmomentarily and, if the seas are high, a small boat can broach —that is, veer on its side with danger of swamping or capsizing. An unintentional jibe in a heavy wind frequently has enough force to break the masts of a vessel. When jibing intentionally, careful sailors always haul in on the boom while turning, so that the boom willtravel...
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War of 1812 - History.
the thorough training they received in handling guns was far ahead of contemporary British standards. As hostilities loomed, Congress authorized a regular army of 35,000 men, but when the United States officially declared war in June 1812, the actual land force was lessthan 10,000 and nearly half of these soldiers were raw recruits. The existing troops were also widely scattered in small garrisons. The government planned tosupplement this regular force with 50,000 volunteers and 100,000 militiam...
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War of 1812 - U.
the thorough training they received in handling guns was far ahead of contemporary British standards. As hostilities loomed, Congress authorized a regular army of 35,000 men, but when the United States officially declared war in June 1812, the actual land force was lessthan 10,000 and nearly half of these soldiers were raw recruits. The existing troops were also widely scattered in small garrisons. The government planned tosupplement this regular force with 50,000 volunteers and 100,000 militiam...
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Cancer (medicine).
unable to repair the DNA damage, p53 instructs the cell to undergo programmed cell death, or apoptosis , putting a stop to runaway cell division before it starts. Programmed cell death is a normal part of cell life and is tightly controlled by many genes, primarily p53. In a cancerous cell, one or more mutations prevent these genes from doing their jobs. When mutated, p53 allows a cell to continue to divide, even with damaged DNA.This can lead to additional mutations in proto-oncogenes or tumor...
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Pottery
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INTRODUCTION
Pottery, clay that is chemically altered and permanently hardened by firing in a kiln.
basket, or a clay or plaster form. Liquid clay can be poured into plaster molds. A pot can be coil built: Clay is rolled between the palms of the hands and extended intolong coils, a coil is formed into a ring, and the pot is built up by superimposing rings. Also, a ball of clay can be pinched into the desired shape. The most sophisticatedpottery-making technique is wheel throwing. The potter's wheel, invented in the 4th millennium BC, is a flat disk that revolves horizontally on a pivot. Both...
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Canadian Forces.
As the Land Force Command component of the CF, the Canadian army is responsible for land combat and for physically protecting people and land-based resources. Itis the component of the CF most often called on to support international military operations and peacekeeping missions and to maintain order in times of civil unrest. A Organization The 20,900 personnel who comprise the army’s regular force are organized into four geographically based areas. Land Force Atlantic includes the provinces of...
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Blood.
substances. For example, a person who is blood type A positive will not make antibodies against the A or Rh markers, but will make antibodies against the B marker,which is not on that person’s own red blood cells. If blood containing the B marker (from types B positive, B negative, AB positive, or AB negative) is transfused into thisperson, then the transfused red blood cells will be rapidly destroyed by the patient’s anti-B antibodies. In this case, the transfusion will do the patient no good a...
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Anatomy.
The body defends itself against foreign proteins and infectious microorganisms by means of a complex dual system that depends on recognizing a portion of the surfacepattern of the invader. The two parts of the system are termed cellular immunity, in which lymphocytes are the effective agent, and humoral immunity, based on theaction of antibody molecules. When particular lymphocytes recognize a foreign molecular pattern (termed an antigen), they release antibodies in great numbers; other lymphocy...
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Skin.
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INTRODUCTION
Skin, outer body covering of an animal. The term skin
III SKIN APPENDAGES In humans, the skin appendages, or structures embedded in the skin, include hair, nails, and several types of glands. Glands are groups of cells that produce andsecrete substances needed by other parts of the body. In other vertebrates, the skin appendages include scales (in fish and reptiles) and feathers (in birds). Together,the skin and the skin appendages are known as the integumentary system of the body. A Hair Hair is a distinguishing characteristic of mammals, a gro...
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Drug.
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INTRODUCTION
Drug, substance that affects the function of living cells, used
normalizing chemical activity in the emotional centers of the brain. Antianxiety drugs, also referred to as tranquilizers, treat anxiety by decreasing the activity in theanxiety centers of the brain. Sedative-hypnotic drugs are used both as sedatives to reduce anxiety and as hypnotics to induce sleep. Sedative-hypnotic drugs act by reducing brain-cell activity.Stimulant drugs, on the other hand, increase neuronal (nerve cell) activity and reduce fatigue and appetite. Analgesic drugs reduce pain...
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Surgery.
III SURGICAL PROCEDURES Surgical procedures are classified as optional, required, elective, urgent, and emergent based on the patient’s medical condition. Optional surgery consists of operationsthat are not required but which the patient chooses to undergo as with some types of cosmetic surgery. Required surgery is performed when only surgery will correct aproblem—such as cataracts—but the surgery can be delayed for a period of weeks or months. Elective surgical procedures usually involve cond...
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Stress (psychology).
blood flow is diverted from the internal organs and skin to the brain and muscles. Breathing speeds up, the pupils dilate, and perspiration increases. This reaction issometimes called the fight-or-flight response because it energizes the body to either confront or flee from a threat. Another part of the stress response involves the hypothalamus and the pituitary gland, parts of the brain that are important in regulating hormones and many otherbodily functions. In times of stress, the hypothal...
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Panama Canal - Geography.
The size of ships using the Panama Canal has steadily increased. About 27 percent of the vessels that use the canal are built to the maximum dimensions that can passthrough it (a category called “Panamax”). This has prompted further widening of Gaillard Cut, so that the larger Panamax vessels may transit safely. However, some ofthe world’s commercial and military ships are too large for the canal. Since the 1940s, new U.S. battleships and aircraft carriers have been built exceeding the canal’sdi...
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Respiratory System.
rapidly, or laughs while swallowing, the swallowing reflex may not work, and food or fluid can enter the larynx. Food, fluid, or other substances in the larynx initiate acough reflex as the body attempts to clear the larynx of the obstruction. If the cough reflex does not work, a person can choke, a life-threatening situation. TheHeimlich maneuver is a technique used to clear a blocked larynx ( see First Aid). A surgical procedure called a tracheotomy is used to bypass the larynx and get air to...
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From Bulfinch's Mythology: The Golden Fleece - anthology.
It remained to lull to sleep the dragon that guarded the fleece, and this was done by scattering over him a few drops of a preparation which Medea had supplied. Atthe smell he relaxed his rage, stood for a moment motionless, then shut those great round eyes, that had never been known to shut before, and turned over on his side,fast asleep. Jason seized the fleece and with his friends and Medea accompanying, hastened to their vessel before Æetes the king could arrest their departure, andmade the...
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Panama Canal - geography.
LockA lock is a section of a waterway enclosed by gates at either end to allow ships to be raised or lowered to a different water level. Inthis example, a ship enters the upper level and the gates close behind it. The water is then allowed to drain into the lower level,lowering the water level of the lock and the ship. When the water level of the lock equals the level of the lower canal, the lower gateswill open and the ship can proceed.© Microsoft Corporation. All Rights Reserved. The canal’s 1...
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From Bulfinch's Mythology: Bacchus (Dionysus) - anthology.
me their fishing rods and nets and their fisherman's trade. This I followed for some time, till growing weary of remaining in one place, I learned the pilot's art and howto guide my course by the stars. It happened as I was sailing for Delos we touched at the island of Dia and went ashore. Next morning I sent the men for fresh water,and myself mounted the hill to observe the wind; when my men returned bringing with them a prize, as they thought, a boy of delicate appearance, whom they hadfound a...
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Shang Dynasty - History.
The dynastic ancestors belonged to an elaborate religious pantheon that also included various nature powers and the Shang high god, Di. The higher powers were lessconcerned with the well-being of Shang society than the ancestors were. Di, whose wishes were often hard to determine, could even cause the Shang harm. The naturepowers could occasionally influence the wind, rain, and harvests, but only Di could actually order the weather. For an agricultural society such as the Shang, this wasperhaps...
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Submarine.
B Propulsion Modern submarines use either diesel-electric or nuclear power to drive the sub's propeller and to provide internal electric power. Diesel-electric power emerged as themost efficient propulsion system for submarines in the early 20th century, following unsuccessful attempts to use steam or gasoline power. While on the surface, thesubmarine uses a diesel engine to drive the propeller and generate electricity. When submerged, a battery-driven electrical motor takes over for propulsion...
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Articles of Confederation - U.
trade, or any other pretence whatever. VIII ARTICLE IV The better to secure and perpetuate mutual friendship and intercourse among the people of the different states in this union, the free inhabitants of each of thesestates, paupers, vagabonds and fugitives from Justice excepted, shall be entitled to all privileges and immunities of free citizens in the several states; and the people ofeach state shall have free ingress and regress to and from any other state, and shall enjoy therein all the...
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Insect - biology.
they almost always have six legs. In some insects, such as beetles, the legs are practically identical, but in other insects each pair is a slightly different shape. Still otherinsects have specialized leg structures. Examples are praying mantises, which have grasping and stabbing forelegs armed with lethal spines, and grasshoppers andfleas, which have large, muscular hind legs that catapult them into the air. Mole crickets’ front legs are modified for digging, and backswimmers have hind legs de...
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Heart.
situation. A Cardiac Cycle Although the right and left halves of the heart are separate, they both contract in unison, producing a single heartbeat. The sequence of events from the beginning ofone heartbeat to the beginning of the next is called the cardiac cycle. The cardiac cycle has two phases: diastole, when the heart’s chambers are relaxed, and systole,when the chambers contract to move blood. During the systolic phase, the atria contract first, followed by contraction of the ventricles. T...
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Musical Instruments
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INTRODUCTION
World Music Tour
Click on the instruments to hear music from around the world.
Traditional Timbila of MozambiqueAmong the Chopi, who have lived for centuries along the coast of Mozambique, there is a highly developed tradition ofsongwriting and composing for timbila (xylophone) orchestras. Elaborate migodo (dance suites), interspersed with poeticsongs pertaining to village life, are often performed to these compositions. Timbila music is now recognized as the nationalmusic of Mozambique."Eduardo Durao Mauaia" from Eduardo Durao and Orquestra Durao: Timbila (Cat.# Globestyl...
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Coronary Heart Disease.
when a patient is at rest may indicate that the blood supply of the heart is not normal, and the ECG can often detect damage from a previous heart attack. In anexercise stress test, an ECG is recorded while a patient is performing physical activity such as walking on a treadmill or riding a stationary bicycle. As the intensity ofexercise increases, the doctor looks for specific changes in the ECG that indicate the heart is not getting enough oxygen. In cardiac catheterization, a long, thin, flex...
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Comparative Anatomy.
In comparing two species, anatomists have to be careful to differentiate between homologous structures, which are ones that have evolved from a shared ancestor, andanalogous structures, which have developed from different origins. Homologous structures are built on the same underlying plan. A human arm, a bat’s wing, and awhale’s flipper look quite different from the outside, but the bones inside reveal that these limbs all have the same basic structure. Analogous structures, by contrast,often l...
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From Gibbons v.
Can a trading expedition between two adjoining States, commence and terminate outside of each? And if the trading intercourse be between two States remote fromeach other, must it not commence in one, terminate in the other, and probably pass through a third? We are now arrived at the inquiry—What is this power? It is the power to regulate, that is, to prescribe the rule by which commerce is to be governed. This power, like all others vested in Congress, is complete in itself, maybe exercised to...
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Alaska - geography.
depression surrounded by highlands and have the coldest winter and hottest summer temperatures in Alaska. Once the Kuskokwim River passes through theKuskokwim Mountains, it forms the southern edge of a vast lake-studded alluvial plain bounded on the north by the Yukon River. This water-logged lowland is a majorsummer nesting area for birds. Fairbanks is the major city in this region, while Fort Yukon is the major community in the Yukon Flats and Bethel the largest settlementon the Lower Kuskokwi...
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Alaska - USA History.
depression surrounded by highlands and have the coldest winter and hottest summer temperatures in Alaska. Once the Kuskokwim River passes through theKuskokwim Mountains, it forms the southern edge of a vast lake-studded alluvial plain bounded on the north by the Yukon River. This water-logged lowland is a majorsummer nesting area for birds. Fairbanks is the major city in this region, while Fort Yukon is the major community in the Yukon Flats and Bethel the largest settlementon the Lower Kuskokwi...
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Ferdinand Magellan
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INTRODUCTION
Ferdinand Magellan (1480?
reduced fleet and brought it to its goal, the Moluccas, where he took on a cargo of cloves. One ship tried to return across the Pacific but was forced back by the windsand then captured by the Portuguese, who interned its crew. Cano made the long westward return voyage with one last ship, the Victoria . After a difficult voyage, with a remaining crew of 18, the Victoria reached Sanlúcar de Barrameda on September 6, 1522, almost three years to the day after setting forth. The cargo of cloves s...
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Ferdinand Magellan.
reduced fleet and brought it to its goal, the Moluccas, where he took on a cargo of cloves. One ship tried to return across the Pacific but was forced back by the windsand then captured by the Portuguese, who interned its crew. Cano made the long westward return voyage with one last ship, the Victoria . After a difficult voyage, with a remaining crew of 18, the Victoria reached Sanlúcar de Barrameda on September 6, 1522, almost three years to the day after setting forth. The cargo of cloves s...
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Ferdinand Magellan - explorer.
reduced fleet and brought it to its goal, the Moluccas, where he took on a cargo of cloves. One ship tried to return across the Pacific but was forced back by the windsand then captured by the Portuguese, who interned its crew. Cano made the long westward return voyage with one last ship, the Victoria . After a difficult voyage, with a remaining crew of 18, the Victoria reached Sanlúcar de Barrameda on September 6, 1522, almost three years to the day after setting forth. The cargo of cloves s...
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Japanese Art and Architecture
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INTRODUCTION
Otani Oniji as Eitoku
Otani Oniji as Eitoku is one of a number of woodblock prints created by the artist T? sh ?sai Sharaku between 1794 and
1795 during the Edo period in Japan.
Jō mon PotteryJapan’s J ōmon people, who thrived from 10,000 to 300 bc, made distinctive pottery for boiling, steaming, and storing food.The pots were made with coils of clay and then decorated by rolling carved sticks, plant fibers, or braided cords over theouter surface. This cord-marked (j ōmon) pottery gave the culture its name.Scala/Art Resource, NY The first settlers of Japan, the J ōmon people (10,000?-300? BC), named for the cord markings that decorated the surfaces of their clay vessel...
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Fur Trade in North America - Canadian History.
Injured by the competition from the North West Company, the Hudson’s Bay Company changed its methods in the late 18th century and began extending its operationsinland. After a period of intense and often violent conflict, the two companies merged in 1821 under the charter of the Hudson’s Bay Company. The trade monopoly andpower to govern that had been originally given to Hudson’s Bay in 1670 were extended to all British-held territory west of Rupert’s Land. The company dominated mostof present-d...
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Great Lakes - Geography.
of 1972 and 1978, have focused on water-quality problems in the Great Lakes. The International Joint Commission on the Great Lakes, established under the BoundaryWaters Treaty, implements and oversees these agreements and has limited authority to regulate obstructions or diversions of boundary waters that would affect thenatural level or flow of lake waters. B Exotic Species The fish populations of the lakes have changed dramatically in the 20th century; changes were wrought at first by overfis...
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Exercise.
broad, and most studies suggest a positive relationship between physical fitness and mental achievement. The relationship between regular aerobic exercise and cardiovascular health and longevity is well established. Regular exercise leads to a reduction in the risk ofcoronary heart disease, in which fatty deposits (plaque) form in blood vessels supplying the muscular wall of the heart, compromising oxygen delivery to the heartmuscle. In addition, with regular exercise the efficiency of the heart...
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Laser.
their atoms into laser light. Consequently, they are the most powerful continuous wave (CW) lasers—that is, lasers that emit light continuously rather than in pulses. C Liquid Lasers The most common liquid laser media are inorganic dyes contained in glass vessels. They are pumped by intense flash lamps in a pulse mode or by a separate gas laserin the continuous wave mode. Some dye lasers are tunable, meaning that the color of the laser light they emit can be adjusted with the help of a prism lo...
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Heat (physics)
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INTRODUCTION
Heat Loss from a House
A thermograph shows the large amount of heat lost through a house's windows during winter.
Theoretically, the molecules of a substance would exhibit no activity at the temperature termed absolute zero. See Molecule. III TEMPERATURE SCALES Five different temperature scales are in use today: the Celsius scale, known also as the Centigrade scale, the Fahrenheit scale, the Kelvin scale, the Rankine scale, andthe international thermodynamic temperature scale ( see Thermometer). The Celsius scale, with a freezing point of 0° C and a boiling point of 100° C, is widely used throughout the...
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Plant - biology.
B1 Vacuoles Vacuoles are membrane-bound cavities filled with cell sap, which is made up mostly of water containing various dissolved sugars, salts, and other chemicals. B2 Plastids Plastids are types of organelles, structures that carry out specialized functions in the cell. Three kinds of plastids are important here. Chloroplasts contain chlorophyllsand carotenoid pigments; they are the site of photosynthesis, the process in which light energy from the sun is fixed as chemical energy in the b...
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Milwaukee - geography.
acts ranging from alternative rock to country music. During the rest of the summer months, the park is the site of weekend festivals staged by Milwaukee’s majorethnic groups: Italian, Irish, German, African American, Polish, Mexican, Native American, and Asian. The Great Circus Parade, featuring the world’s largest collection ofornate circus wagons, is another staple of Milwaukee’s festival season. The Wisconsin State Fair is held annually in nearby West Allis. V RECREATION The largest single u...
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Radioactivity
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INTRODUCTION
Marie Curie
Working with her husband, Pierre Curie, French physicist Marie Curie discovered the radioactive elements polonium and
radium in 1898.
Rutherford when he allowed an alpha-emitting substance to decay near an evacuated thin-glass vessel. The alpha particles were able to penetrate the glass and werethen trapped in the vessel, and within a few days the presence of elemental helium was demonstrated by use of a spectroscope. Beta particles were subsequentlyshown to be electrons, and gamma rays to consist of electromagnetic radiation of the same nature as X rays but of considerably greater energy. A The Nuclear Hypothesis Rutherford...
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Maya Civilization.
destruction was directed mostly at temples in the ceremonial precincts; it had little or no impact on the economy or population of a city as a whole. Some city-states didoccasionally conquer others, but this was not a common occurrence until very late in the Classic period when lowland civilization had begun to disintegrate. Until thattime, the most common pattern of Maya warfare seems to have consisted of raids employing rapid attacks and retreats by relatively small numbers of warriors, most o...
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Maya Civilization - History.
destruction was directed mostly at temples in the ceremonial precincts; it had little or no impact on the economy or population of a city as a whole. Some city-states didoccasionally conquer others, but this was not a common occurrence until very late in the Classic period when lowland civilization had begun to disintegrate. Until thattime, the most common pattern of Maya warfare seems to have consisted of raids employing rapid attacks and retreats by relatively small numbers of warriors, most o...
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Ontario - Geography.
governed Ontario’s initial settlement and development. The province’s most important river is the St. Lawrence. Its route was much improved and enlarged by dredgingand canal building in the mid-20th century. This enabled large ocean-going vessels to reach Great Lake ports ( see St. Lawrence Seaway). The Ottawa River was an important early route to the interior for fur traders and timber merchants. The Niagara River, because of its falls, is a great center of hydroelectric power as well as aninte...
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Ontario - Canadian History.
governed Ontario’s initial settlement and development. The province’s most important river is the St. Lawrence. Its route was much improved and enlarged by dredgingand canal building in the mid-20th century. This enabled large ocean-going vessels to reach Great Lake ports ( see St. Lawrence Seaway). The Ottawa River was an important early route to the interior for fur traders and timber merchants. The Niagara River, because of its falls, is a great center of hydroelectric power as well as aninte...
- Hypertension.
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- Lymphatic System.
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Kidney.
secretion. An additional function of the kidney is the processing of vitamin D; the kidney converts this vitamin to an active form that stimulates bone development. Several hormones are produced in the kidney. One of these, erythropoietin, influences the production of red blood cells in the bone marrow. When the kidney detectsthat the number of red blood cells in the body is declining, it secretes erythropoietin. This hormone travels in the bloodstream to the bone marrow, stimulating theproducti...