541 résultats pour "wat"

• Water - chemistry.

  flourides in drinking water has been found to reduce tooth decay. See Fluorine. Seawater contains, in addition to concentrated amounts of sodium chloride, or salt, many other soluble compounds, as the impure waters of rivers and streams areconstantly feeding the oceans. At the same time, pure water is continually lost by the process of evaporation, and as a result the proportion of the impurities that givethe oceans their saline character is increased. See Ocean and Oceanography. VII WATER...

• Water Cycle.

  salt water into groundwater in densely populated low-lying coastal regions. Levees are built to control the course of rivers, and dams are built to render riversnavigable, store water, and provide electrical power. Evaporation of water behind dams is a serious source of water loss. Increasing urbanization has led to more severeflooding because rainwater reaches streams more rapidly and in greater quantity from areas where the ground has been paved. As human population continues to grow, effectiv...

• Water Pollution.

  Cryptosporidium in the water supply of Milwaukee, Wisconsin, sickened more than 400,000 people and killed more than 100. H Thermal Pollution Water is often drawn from rivers, lakes, or the ocean for use as a coolant in factories and power plants. The water is usually returned to the source warmer than when itwas taken. Even small temperature changes in a body of water can drive away the fish and other species that were originally present, and attract other species in placeof them. Thermal pol...

• problems associated with water shortage

  In Iran a group of farmers destroyed a water pump station that was carrying water away from their area to another city. So we can see that the world’s water problems can be the source of conflicts Climate change has also exacerbated water issues worldwide. In fact, climate change is drying up lakes, rivers and seas everywhere. In Australia, for example, a heat wave created wildfires and critical water shortages. In some places, it’s just too dry, and people who live there n...

• Le water-polo

  • Le but peut être marqué de n'importe quel endroit de l'aire de jeu. Le gardien est le seul joueur dont les mouvements sont limités : il ne peut dépasser la ligne de mi-distance ni toucher le ballon au-delà de cette ligne. • Un but peut être marqué avec tout le corps, sauf avec le poing fermé. • Pour qu'un but soit valable, il faut que deux joueurs au moins ait touché la balle durant la phase de jeu qui conduit au but Les buts directs...

• Ship. I 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...

• Nuclear Energy I INTRODUCTION Gundremmingen Nuclear Power Plant, Germany The first of three boiling-water nuclear reactors at Germany's Gundremmingen plant began operating in 1966 but was permanently shut down after being decommissioned in 1983.

  such as ¯U is induced by the absorption of a neutron as in producing cesium-140, rubidium-93, three neutrons, and 200 MeV, or 3.2 × 10 -11 J (7.7 × 10 -12 cal). A nuclear fission reaction releases 10 million times as much energy as is released in a typical chemical reaction. See Nuclear Chemistry. III NUCLEAR ENERGY FROM FISSION The two key characteristics of nuclear fission important for the practical release of nuclear energy are both evident in equation (2). First, the energy per fiss...

• Temple (building) I INTRODUCTION Wat Phra Kaeo Thailand has nearly 18,000 Buddhist temples, called wats, throughout the country.

  colonnaded terraces connected by ramps. The surrounding area was planted with trees and flowers during Hatshepsut’sreign and for many years after.Gian Berto Vanni/Art Resource, NY In ancient Egypt, temples were grandiose, built of huge blocks and columns of stone. Often they were enlarged by successive rulers to form strung-out series of templeparts, as in the gigantic Temple of Amon (circa 1550-1070 BC) at Al Karnak. The Nile cliffs were used as settings for temples, such as the massive mortuar...

• 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...

• Angkor Wat - geography.

• water-polo - sport.

  dominé par le CN Marseille et par le Cacel Nice. Le Championnat de France dames a souvent été remporté ces dernières années par l'équipe des Dauphins de Créteil. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. Tous droits réservés.

• Irish Water Spaniel.

• Portuguese Water Dog.

• irish water spaniel (faune & Flore).

• Angkor Wat und Angkor Thom (Architektur).

• water-polo.

• Rain. I INTRODUCTION Rain, precipitation of liquid drops of water. Raindrops generally have

• Water Music [Georg Friedrich Haendel] - analyse de l'oeuvre musicale.

• George Frideric Handel I INTRODUCTION Handel's Water Music In addition to his popular operas and oratorios, German-born composer George Frideric Handel wrote music in the 1700s for the church and for royal celebrations.

  During the 1720s and 1730s Handel worked primarily as a composer and producer of operas for the London stage. This extremely productive phase of his career beganwith the opening of the Royal Academy of Music in London in 1719. The Royal Academy was founded with the support of the king and aristocratic subscribers for theproduction of Italian operas. Its directors sent Handel to continental Europe to hire some of the world’s greatest singers. Handel was not the only composer writingoperas for Aca...

• Naiads (Naiades) Greek Nymphs of fresh bodies of water, such as springs, wells, brooks, streams, lakes, and marshes.

• Water scarcity

  Water scarcity 1. There is a limited amount of water for numerous reasons. Firstly, fresh water only represents 3% of the world’s water. Moreover water scarcity is indeed an important factor when we talk about water availability. Currently, the demand of water is greater than the water supply the region or country has. However physical water scarcity can occur when there is enough water but simply not enough for the growing needs of the population ; especially if the population wishes t...

• Thaïlande. Ayutthaya, le Wat Phanam Choeng.

• water-ballast.

• Le water-polo

  • Le Nt peut être marqué de n'importe quel endroit de l'aire de jeu. Le gard ien est le seul joueur dont les mouvements sont limités : il ne peut dépasser la ligne de mi-

• Thaïlande. Sukhôthaï, lac face au Wat Traphang Ngon.

• Otter Otters are water-loving animals found everywhere except Australia, New Zealand, and Antarctica.

• Recherche scientifique

  Background: Nosocomial infection caused by non-Enterobacteriaceae gram negative bacteria (GNB-NE) is increasing in intensive care units (ICU). Aim: The objective of this study was to determine whether potable water in ICU wards at Tehran hospitals is contaminated with L. pneomophila, P. aeroginosa and Acinetobacter spp. Materials and Methods: A total of 52 water samples from shower bath and taps water in seven hospitals of Tehran were collected. The water sample concentrated by...

• Wetland.

  Other plants and animals have special adaptations suited for living in a wet environment. Most emergent plants have air spaces in their stems that enable oxygen to betransported to roots that grow in sediments with no oxygen. Some of the trees that grow in swamps form a set of roots above the soil surface or above the water thatallows them to get oxygen to the lower roots. In saltwater wetlands, specialized cells can limit the amount of salt that enters a plant, or specialized organs can excrete...

• Colorado (river, North America) - Geography.

  sometime between AD 1300 and 1400, but their descendants, the Hopi and Pueblo people, continue to farm and irrigate using the river's waters. The first European to visit the river was probably Spanish soldier and explorer Francisco de Ulloa, who explored the mouth of the Colorado in 1539. In 1540 and 1541another Spaniard, Francisco Vásquez de Coronado, traveled through much of the region around the Colorado River. An exploring party from the Coronado expedition,led by Garcia López de Cárdenas,...

• River.

  IV RIVER PATTERNS River patterns, or general shapes, depend on the geologic zone and the climate of the location. There are four river patterns: meandering, braided, anastomosing, andstraight. A meandering pattern follows a winding, turning course. A braided pattern has connected channels that resemble a hair braid. An anastomosing river patterncombines features of the meandering and braided patterns. Some river patterns are simply straight channels. Meandering and braided are the most common...

• River - Geography.

  IV RIVER PATTERNS River patterns, or general shapes, depend on the geologic zone and the climate of the location. There are four river patterns: meandering, braided, anastomosing, andstraight. A meandering pattern follows a winding, turning course. A braided pattern has connected channels that resemble a hair braid. An anastomosing river patterncombines features of the meandering and braided patterns. Some river patterns are simply straight channels. Meandering and braided are the most common...

• Ocean and Oceanography.

  of sediment. When studied in sedimentary core samples, which can represent many millions of years of deposits, they provide a detailed and continuous history of theearth’s environmental changes. The record is particularly informative for the most recent 2 million to 5 million years, during which major fluctuations in global climatehave occurred. Successive ice ages can be traced by the relative scarcity or abundance of the shells of warm-water and cold-water diatoms in various layers of asedimen...

• Ocean and Oceanography - Geography.

  of sediment. When studied in sedimentary core samples, which can represent many millions of years of deposits, they provide a detailed and continuous history of theearth’s environmental changes. The record is particularly informative for the most recent 2 million to 5 million years, during which major fluctuations in global climatehave occurred. Successive ice ages can be traced by the relative scarcity or abundance of the shells of warm-water and cold-water diatoms in various layers of asedimen...

• Heat (physics) I 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...

• Swimming.

  the swimmer and the pinky finger should enter the water first. At the same time, the swimmer moves the left arm through the water below the left side of the body.Once in the water, the right arm begins pulling the swimmer forward by bending at the elbow. At the same time the swimmer holds the left arm straight as it reachesthe hip and lifts it out of the water. As the right arm continues to pull, the swimmer rotates slightly onto the right side and swings the left arm up above the head. As the s...

• River - geography.

  In very large rivers, the water comes from rain that may have fallen as far as 6,000 km (4,000 mi) away. During the journey through rills and streams, the water’s flowmay erode and deposit sediment in the river’s channel and on its floodplain ( see Erosion; Deposit). The biggest rivers usually carry the largest amount of sediment. Yet some of the largest rivers may carry very little sediment because the watershed may not have a lot of sediment. A river carries the most sediment when the flow is...

• Earth (planet).

  Milky Way to complete one revolution around the Galaxy’s center. Earth’s axis of rotation is inclined (tilted) 23.5° relative to its plane of revolution around the Sun. This inclination of the axis creates the seasons and causes the height of the Sun in the sky at noon to increase and decrease as the seasons change. The Northern Hemisphere receives the most energy from the Sun when it is tiltedtoward the Sun. This orientation corresponds to summer in the Northern Hemisphere and winter in the S...

• Earth (planet) - astronomy.

  Milky Way to complete one revolution around the Galaxy’s center. Earth’s axis of rotation is inclined (tilted) 23.5° relative to its plane of revolution around the Sun. This inclination of the axis creates the seasons and causes the height of the Sun in the sky at noon to increase and decrease as the seasons change. The Northern Hemisphere receives the most energy from the Sun when it is tiltedtoward the Sun. This orientation corresponds to summer in the Northern Hemisphere and winter in the S...

• Hydrogen - chemistry.

  Hydrogen gas does not usually react with other chemicals at room temperature. That is, it does not split into two hydrogen atoms to combine with other chemicals. Thebond between the hydrogen atoms is very strong and can only be broken with a large amount of energy. However, when heated with a flame or a spark, hydrogen gaswill react violently with oxygen in the air to produce water in the following reaction: 2H2 + O 2 → 2H 2O This chemical equation shows that two hydrogen molecules (H 2) and o...

• Gardening - biology.

  of synthetic and organic fertilizers, see Organic Farming.) Fertilizers usually are sold in packages, on which the percentage by weight of the macronutrients nitrogen (N), phosphorus (P), and potassium (K) are listed on thelabel—always in the order N-P-K. For example, a fertilizer that is labeled 10-5-3 is 10 percent nitrogen, 5 percent phosphorus, and 3 percent potassium. V PLANTING AND TRANSPLANTING Before planting seeds, gardeners prepare, or till, the soil using a variety of methods. Some...

• Camel - biology.

  of water in the stomach or hump as was once commonly believed. Unlike other mammals, however, the camel can survive as long as three weeks without drinking,depending on the water content of its food. It can survive a water loss of about 40 percent of its normal body weight. In comparison, a loss of 15 percent is usually fatalfor humans. Camels can go without water due to several unique adaptations to their environment. The camel conserves more water in its body than any other mammal. It excretes...

• Middle East - geography.

  years.Spectrum Colour Library Apart from the Nile River, which provides much of the water supply and irrigation systems of Egypt, and the Tigris and Euphrates rivers, which supply Iraq, Syria, andTurkey, there are no major rivers or navigable waterways. The Sea of Galilee (Lake Tiberias) in northern Israel, fed from the north by the shallow, unnavigable JordanRiver, provides Israel’s main source of fresh water. With such a limited water supply, access to water for drinking, irrigation, and hydro...

• Fish - biology.

  pectoral fins provide fine movements, add forward thrust, or, together with the pelvic fins, serve as brakes. Typically, fins consist of a thin membrane stretched over afanlike series of thin rods called spines or rays. Most fish breathe underwater with the help of special respiratory organs called gills. Gills are made of a series of thin sheets or filaments through which blood circulates.As water moves into a fish’s mouth and passes over the gills, dissolved oxygen passes across the thin gill...

• Frog (animal).

  which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...

• Frog (animal) - biology.

  which means that their body temperature depends on the temperature of the surrounding environment. Few species can tolerate temperatures below 4°C (40°F) orabove 40°C (104°F), and many species can survive only within a narrower range of temperatures. In addition, frogs’ thin, moist skin offers little protection againstwater loss, and when on land the animals must guard against drying out. Many frogs are active at night because temperatures are cooler and humidity is higher thanduring the day. In...

• 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...

• Amphibian (animal) - biology.

  strong enough to kill potential predators. C Hearing, Vision, and Vocalizations Amphibians rely on their senses to find food and evade predators. Amphibians lack external ears but have well-developed internal ears. Hearing is most acute in frogs,which typically have a middle ear cavity for transferring sound vibrations from the eardrum, or tympanum, to the inner ear. Frogs and toads also use their keen hearingin communicating with one another. Using a true voice box, or larynx, and a large, exp...

• Duck - biology.

  from water. When ducks feed they push their tongue against the top of their mouth to squeeze water through the lamellae, leaving the food behind. Mergansers arefish-eating ducks with slender bills that are notched on the edges like the blade of a saw. These saw-toothed beaks help the ducks catch and hold their slippery prey. VI COURTSHIP AND REPRODUCTION Ducks form pairs long enough to mate, but most species find new mates each year. In a few species, including buffleheads and whistling ducks,...

• 1769: Water Frame

• Moon - astronomy.

  B Volcanic Features Maria, domes, rilles, and a few craters display indisputable characteristics of volcanic origin. Maria are plains of dark-colored rock that cover approximately 40 percent ofthe Moon's visible hemisphere. The maria formed when molten rock erupted onto the surface and solidified between 3.16 billion and 3.96 billion years ago. This rockresembles terrestrial basalt, a volcanic rock type widely distributed on Earth, but the rock that formed the maria has a higher iron content an...