3232 résultats pour "système"

• Grands navigateurs et seuls maîtres de la Méditerranée du XI e au VIII e siècle avant J.

  et égyptien. Plusieurs historiens s'accordent à faire correspondre le début de l'histoire phénicienne avec cette période du début de l'âge du fer : dégagée de la menace égyptienne et hittite, la Phénicie connut un remarquable essor, malgré les ravages qu'avaient causés les nouveaux envahisseurs (destruction d'Ougarit, de Sidon et d'Arvad). C'est alors qu'elle développa sa vocation maritime, noua des liens commerciaux avec l'ensemble du bassin méditerranéen et imposa pour trois siècles (du XI e a...

• Robot.

  V IMPACT OF ROBOTS Robotic manipulators create manufactured products that are of higher quality and lower cost. But robots can cause the loss of unskilled jobs, particularly on assemblylines in factories. New jobs are created in software and sensor development, in robot installation and maintenance, and in the conversion of old factories and the designof new ones. These new jobs, however, require higher levels of skill and training. Technologically oriented societies must face the task of retra...

• Définition: BRISE, substantif féminin.

  SYNTAXE : Briser le cachet d'une lettre; briser le crâne, les os de quelqu'un; briser les idoles, des portes, un verre. — Spécialement. TECHNOLOGIE. Briser la laine, le chanvre, etc. En séparer les fibres pour les démêler. · Briser des chaussures. Les assouplir. — Locution figurée. Briser la glace. Supprimer la gêne ou la contrainte dans des relations humaines : Ø 2. Et ce n'est pas de rencontrer davantage d'humains qui m'apprendrait à briser la glace, (...); je n'arrive pas à percer ce cercle...

• données, transmission de - informatique.

  Dans le cas simple d’un ordinateur isolé, les distances parcourues par les données à transmettre étant relativement courtes, l’objectif est d’obtenir de très grandes vitesses de transfert. En général, le microprocesseur, la mémoire vive, les contrôleurs de disque, le système d’affichage vidéo et autres interfaces sont reliés par des sortes d’autoroutes électroniques appelées bus, assurant chacune le transport d’un type spécifique d’informations (données, adresses, etc.). Chaque bus se compose d’...

• Le moteur Diesel

  Comparaison des types de combustion MOTEUR DIESEL CD Combustible 0 Air chaud comprimé ®Piston @ Bougie ® Bougie de préchauffage @ Injecteur (!) Gaz d'échappement @ Chambre de combustion @ Cylindre une même rampe (« rail») et la pression d'injection peut être choisie entre 250 et 1 350 bars. Ainsi , grâce à des électrovalve s, on peut obtenir le meilleur dosa g e : plus la pression est importante , plus l'injecteur pulvérise de fines g...

• controverse scientifique - philosophie.

  fonction des méthodes employées par les sociologues. Dans l’étude d’une controverse, on peut, dans un premier temps, commencer par l’analyse des questions de méthode et de doctrine, puis se diriger vers l’examen des facteurs extrascientifiques. 2. 5 Caractéristiques communes des controverses scientifiques D’un point de vue général, toute controverse implique la participation d’au moins deux acteurs. Ces derniers peuvent être simplement deux personnes ou bien de nombreux chercheurs qui s’opposen...

• Internal-Combustion Engine.

  any Otto-cycle engine and in actual engines today is slightly more than 40 percent. Diesels are, in general, slow-speed engines with crankshaft speeds of 100 to 750revolutions per minute (rpm) as compared to 2500 to 5000 rpm for typical Otto-cycle engines. Some types of diesel, however, have speeds up to 2000 rpm. Becausediesels use compression ratios of 14 or more to 1, they are generally more heavily built than Otto-cycle engines, but this disadvantage is counterbalanced by theirgreater effici...

• Kosovo, dix ans d'affrontements

  nous, pas d'incertitude", est réélu avec 65 % des voix. A l'automne 1990, un rapport de la CIA, dont fait état l' International Herald Tribune dans son édition du 29 novembre, estimeque "l'expérience socialiste a échoué, le pays se disloque, et le démembrement de la Fédération sera accompagné de violencesethniques et d'agitation qui conduiront à la guerre civile". Et, déjà, les auteurs du document accusent Slobodan Milosevic d'être leprincipal instigateur des troubles en Yougoslavie en raison...

• Edmonton - Geography.

  both of which built fur trading posts near present-day Edmonton in 1795. The posts were rebuilt several times, always along the North Saskatchewan River, whichprovided the traders’ main transportation route. The last move came in 1830, when Fort Edmonton was erected on the high bluff where the Alberta Legislature nowstands. For the next 50 years, the fort was the major trading center on the western plains. The modern city began to take shape after 1900, when central Alberta was opened to Europea...

• droit fiscal general

  L'év olution des concepts en matière de fiscalité est radicale. En effet, les impôts les plus récents (notamment la CSG, contribution sociale généralisée, et la CRDS, contribution au remboursement de la dette sociale) ne sont pas perçus au profit de collectivit és publiques, mais au profit des URSAFF, qui sont des régimes d'entité privées. La frontière est donc de plus en plus floue. §2. Les buts de l'impôt. L'impôt poursuit...

• Fiches de synthèse Vaisse Relations internationales

  CHAPITRE 1 : NAISSANCE ET CONFRONTATION D’UN MONDE BIPOLAIRE (1945-1955) Introduction : La Seconde Guerre mondiale affaiblit le continent européen qui perd son rôle prééminent. - cela confirme les conséquences de la Première Guerre mondiale - ce déclin est dû au fait que les combats ont particulièrement affecté l’Europe. Cela se traduit par : - la perte de puissance des grands pays européens (Fr, Ang …) - l’émergence de deux supergrands pouvant faire figures de modèles...

• voici à l'heure du grand chamboulement issu de Mai 68, auquel le vieux chef de l'État n'a pas compris grand-chose.

  En guise de conclusion Entre 1945etce début duxxie  siècle, lasociété française s’estconsidérablement transformée.Ausortir dela guerre, laFrance étaitencore trèslargement unpays d’agriculture (prèsd’untiersdelapopulation endépendait), doté parailleurs d’unsecteur industriel employant uneclasse ouvrière importante. Lasociété étaittrèsstructurée par lesgrandes appartenances politiquesetreligieuses : êtrecatholique oulaïque, communiste oudedroite, membre dupatronat oumilitant syndical réglaitlavie...

• Satelliten (Auswahl).

  04.10.1957 Sputnik 1 erster künstlicher Satellit 03.11.1957 Sputnik 2 erste biomedizinische Daten; erstes Lebewesen im All(Hündin Laika) 31.01.1958 Explorer 1 erster US-amerikanischer Satellit; Entdeckung des Van-Allen-Gürtels 07.03.1962 OSO-1 erstes Sonnenobservatorium im Orbit 26.04.1962 Ariel (UK No. 1) erster internationaler Satellit; mit britischen undUS-amerikanischen Instrumenten bestückt 04.09.1964 OGO-1 erstes geophysikalisches Observatorium im Orbit 07.09.1967 Biosatellite brachte lebe...

• infinitésimal, calcul - mathématiques.

  3. 3 Dérivée d’une fonction Lorsque ce nombre dérivé existe en tout point x0 de l’ensemble de définition D de f, on peut alors définir la fonction dérivée de f, notée f’, telle que pour tout x0 appartenant à D, On note également f’ = dy / dx, et on dit que la fonction f est dérivable. Soit une fonction f définie par f(x) = x 2 pour tout x réel. La représentation graphique de f est alors une parabole. On peut alors calculer le taux instantané de variation de f en un point x0. d...

• Phoenix (city, Arizona) - geography.

  The company’s irrigation system followed the network of canals that were built there by the Hohokam some 500 years earlier. In October 1870, several settlers foundedthe site of modern Phoenix. In recognition of the former Hohokam culture, settler Darrell Duppa likened the new community to the phoenix, a mythological bird thatconsumed itself by fire every 500 years and arose anew from the ashes. Thereafter, the group adopted Phoenix as the settlement’s name. Within a short time the areawas produc...

• La vie extraterrestre (Travaux Pratiques Encadrés)

  l'étude des origines et de la distribution de la vie. ~un des objectifs de l'exobiologie est donc de comprendre l'histoire de la vie depuis son origine jusqu'à l'étape actuelle qui a permis l'émergence d'une diversité incroyable d'êtres vivants. ~Europe mène des recherches de manière très active dans ce domaine. Une équipe internationale dirigée par A. Brt1ck du Centre de biophysique moléculaire d'Orléans étudie la vie dans les conditions hostiles...

• En un demi-siècle, la télévision a beaucoup changé.

  Complétez votre recherche en consultant : Les corrélats caméra cathodique (rayon) écran ENG (Electronic News Gathering, en français « reportage d'actualité électronique ») hertzien (faisceau) luminance mondovision NTSC (National Television System Committee) orthicon PAL (Phase Alternative Line) SECAM (séquentiel couleur à mémoire) Westinghouse George Zworykin Vladimir Kosma Les livres télévision - schémas, page 5106, volume 9 antenne réceptrice de télévision...

• desobeissance civile

  même titre que la res publica ou les Lois. C'est cette sorte de personnification qui va rendre plus difficile la désobéissance : il est en effet plus aisé de désobéir à des normes abstraites qu'à des personnes déterminées. Ainsi Socrate a-t-il pu, dans sa prison, s'imaginer que les lois lui parlaient : « Socrate, que vas-tu faire ? L'action que tu entreprends a-t-elle d'autre but que de nous détruire, nous qui sommes les lis, et avec nous l'Etat tout entier (...) »13(*) ; peut parfois s'ajouter...

• A. Grjebine et T. Grjebine, La réforme du système monétaire international

  98 L'explication d'un texte économique l'exportation) certains Etats ne mènent une politique déflationniste; mais cette politique est synonyme de ch.ômage, de ralentissement de la croissance, de crise sociale, etc. 3) Un système monétaire international doit assurer à chaque pays la plus grande indépendance possible en ce qui concerne sa politi­ que économique interne et le choix des objectifs (plein emploi, crois­ sance, etc.) qu'il cherche à atteindre en pri...

• agriculture - agriculture et agroalimentaire.

  de travailler vite et dans les meilleures conditions. Le travail de récolte, fondamental puisque une année d’efforts peut être ruinée ou récompensée, a connu la même évolution : récolte manuelle nécessitant des équipesnombreuses employées de façon temporaire, machines à traction animale comme la moissonneuse-lieuse, machines à traction mécanique, puis automotrices (comme lamoissonneuse-batteuse). La contrepartie de cette mécanisation est la nécessité de confier de grandes surfaces à ces machines...

• Telephone.

  digits is dialed. The development of inexpensive and reliable amplification provided by the introduction of the transistor in the 1960s made practical the design of adialing system based on the transmission of relatively low power tones instead of the higher-power dial pulses. Today most telephones have push buttons instead of a rotary dial. Touch-Tone is an optional service, and telephone companies still maintain the ability to receive pulsedialing. Push-button telephones usually have a switch...

• Kyrgyzstan - country.

  are Bishkek, the capital, located on the Chu River in the far north; and Osh, located in the Fergana Valley. A Ethnic Groups Ethnic Kyrgyz make up about 65 percent of the population of Kyrgyzstan. Uzbeks, who live primarily in the Fergana Valley, constitute about 14 percent of thepopulation. Russians, who live principally in Bishkek and other industrial centers, make up about 13 percent of the population. Other ethnic groups include Hui (ChineseMuslims, also known as Dungans), Ukrainians, Uygur...

• Rocket.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Rocket - astronomy.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Malaria.

  last long and is unlikely to be fatal. Infants and children are especially vulnerable to malaria because they have not yet built up immunity to the parasite. Some peoplehave genetic traits that help them resist malaria. Sickle-cell anemia and thalassemia, for example, are inherited blood disorders linked to malaria resistance. Travelers who lack immunity to malaria should take precautionary measures when visiting areas where the disease is prevalent. Such measures include using insectrepellents,...

• Excerpt from Nicholas Nickleby - anthology.

  After some half-hour's delay Mr Squeers reappeared, and the boys took their places and their books, of which latter commodity the average might be about one toeight learners. A few minutes having elapsed, during which Mr Squeers looked very profound, as if he had a perfect apprehension of what was inside all the books,and could say every word of their contents by heart if he only chose to take the trouble, that gentleman called up the first class. Obedient to this summons there ranged themse...

• Industrial Revolution I INTRODUCTION Industrial Revolution, widespread replacement of manual labor by machines that began in Britain in the 18th century and is still continuing in some parts of the world.

  The most important advance in iron production occurred in 1784 when Englishman Henry Cort invented new techniques for rolling raw iron, a finishing process thatshapes iron into the desired size and form. These advances in metalworking were an important part of industrialization. They enabled iron, which was relativelyinexpensive and abundant, to be used in many new ways, such as building heavy machinery. Iron was well suited for heavy machinery because of its strength anddurability. Because of t...

• Industrial Revolution .

  The most important advance in iron production occurred in 1784 when Englishman Henry Cort invented new techniques for rolling raw iron, a finishing process thatshapes iron into the desired size and form. These advances in metalworking were an important part of industrialization. They enabled iron, which was relativelyinexpensive and abundant, to be used in many new ways, such as building heavy machinery. Iron was well suited for heavy machinery because of its strength anddurability. Because of t...

• Drug. I 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...

• Meteorology.

  to find the corresponding relative humidity and dew-point temperature. III SPECIAL METEOROLOGICAL INSTRUMENTS Meteorologists have developed several sophisticated instruments that measure multiple physical characteristics of the air simultaneously and at more than one location.The most important of these special instruments are radiosondes, Doppler radar, and weather satellites. A Radiosonde A radiosonde measures air temperature, air pressure, and humidity from the earth’s surface up to an alt...

• Vietnam - country.

  E Natural Resources Vietnam’s most valuable natural resource is its land, particularly the fertile, alluvial soils in the Red and Mekong deltas. Some 29 percent of the land is currently beingcultivated. Vietnam has some valuable mineral resources, including gold, iron, tin, zinc, phosphate, chromite, apatite, and anthracite coal. Most deposits are located in the northernpart of the country. Few attempts were made to extract these minerals until the French takeover of Vietnam at the end of the 1...

• Political Parties in the United States.

  quickly enabled the Republican Party to overpower the Know-Nothings. Although the Republicans lost their first campaign for the presidency in 1856, they triumphed in1860 with former congressman Abraham Lincoln. The Republican victory resulted in part from the division of the Democratic Party into Northern and Southern factions,each of which ran its own presidential candidate, and in part from their success at attracting Whigs and Know-Nothings who had opposed the Republicans in 1856.During the C...

• Démocratie La démocratie est le système politique dans lequel le peuple exerce, directement ou indirectement, sa souveraineté: c'est le gouvernement...

  Démocratie La démocratie est le système politique dans lequel le peuple exerce, directement ou indirectement, sa souveraineté: c'est le gouvernement du peuple par lui-même. Le mot est d'origine grecque (il signifie « l'autorité du peuple»). C'est en effet dans un certain nombre de cités grecques que l'on a vu apparaitre les premiers gouvernements démocratiques dans /'Antiquité. La constitution d'Athènes à l'époque classique - aux et siècles avant J.-C. - passe, surtout de ce point de vue, pour e...

• Physics I INTRODUCTION Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces.

  Starting about 1665, at the age of 23, Newton enunciated the principles of mechanics, formulated the law of universal gravitation, separated white light into colors,proposed a theory for the propagation of light, and invented differential and integral calculus. Newton's contributions covered an enormous range of naturalphenomena: He was thus able to show that not only Kepler's laws of planetary motion but also Galileo's discoveries of falling bodies follow a combination of his ownsecond law of m...

• Galaxy - astronomy.

  Astronomers have obtained images of young galaxies using the Keck Telescope in Hawaii and the Hubble Space Telescope, which resides in an orbit high above Earth’satmosphere and thus avoids atmospheric interference. Photos from the HST show galaxies that are as far as 13 billion light-years away from Earth, which means theyformed soon after the universe formed about 13.7 billion years ago. The galaxies appear to be spherical in shape, and may be early precursors of elliptical and spiralgalaxies....

• Colour and qualia

  Faced with the dilemmas posed by subjective colour for physicalist doctrine, some philosophers opt for eliminativism, the doctrine that subjective colour is not a genuine, or real, phenomenon after all. On this view the source of the puzzle is a conceptual confusion; a tendency to extend our judgments concerning objective colour, what appear to be intrinsic properties of the surfaces of physical objects, onto the properties of our mental states. Once we see that all that is happening ‘inside'...

• Airplane.

  For example, the Anglo-French Concorde, a commercial supersonic aircraft, was generally limited to over-water routes, or to those over sparsely populated regions ofthe world. This limitation impacted the commercial viability of the Concorde, which ended its regular passenger service in October 2003. Designers today believe theycan help lessen the impact of sonic booms created by supersonic airliners but probably cannot eliminate them. One of the most difficult practical barriers to supersonic fl...

• Supreme Court of Canada.

  whether the leave to appeal will be granted and the case heard by the Court. The Court has no specified criteria by which it determines whether to grant leave, and the Court does not give reasons for its decision. The key factor appears to be acase’s degree of national importance. Other factors might include the impact of uncertainty in the challenged law, the case’s appropriateness for developing the law torespond to changing social needs, and the presence of a split decision at the court of ap...

• cosmologie - astronomie.

  en expansion. L'Univers serait alors un Univers ouvert de taille infinie. Cependant, si la densité de matière est supérieure à une valeur critique, actuellement estimée à5 × 10 -30 g/cm 3, l'attraction gravitationnelle ralentira l’expansion de l’Univers jusqu'à l'arrêter et l'inverser en contraction : l'Univers s'effondrera totalement. Il serait alors « fermé », d'étendue limitée. Le destin de l'Univers effondré est incertain ; selon une théorie, dite de l’Univers oscillant, il exploserait à nou...

• l'époque.

  Cette sombre histoiresemet enplace auxAntilles danslapremière moitiéduxviie siècle. Ellecesse en1848. Elle aura donc durédeux siècles. Onnepeut, danscelivre, tourner lapage surcette immense tachesurnotre mémoire sans évoquer lesquelques réflexions qu’ellesuscite. L’esclavage, plaieuniverselle L’esclavage n’estpasune spécialité réservéeparl’Europe occidentale auNouveau Mondequ’ellevenaitde conquérir. Laplupart dessociétés humaines enont faitusage. L’Afrique leconnaissait bienavant l’arrivée du pr...

• Stem Cell.

  The medical profession used adult stem cells to treat diseases long before anyone isolated one. In 1968 scientists performed the first successful bone marrowtransplant, a procedure in which a patient receives an infusion of healthy bone marrow cells. The purpose of such transplants is to restore the blood-making capabilitiesof the patient’s diseased bone marrow after extremely strong chemotherapy has destroyed that bone marrow. From the beginning investigators suspected that stemcells in the inf...

• Human Disease.

  disease can be transmitted through food infected with mutated proteins. B Spread of Infectious Disease Some pathogens are spread from one person to another by direct contact. They leave the first person through body openings, mucous membranes, and skin wounds,and they enter the second person through similar channels. For example, the viruses that cause respiratory diseases such as influenza and the common cold are spreadin moisture droplets when an infected person coughs or sneezes. A hand that...

• Drug Dependence.

  these drugs develops rapidly, no withdrawal syndrome is apparent when they are discontinued. Phencyclidine, or PCP, known popularly by such names as “angel dust” and “rocket fuel,” has no medical purpose for humans but is occasionally used by veterinarians asan anesthetic and sedative for animals. It became a common drug of abuse in the late 1970s, and is considered a menace because it can easily be synthesized. Itseffects differ from those of other hallucinogens. LSD, for example, produces deta...

• United States House of Representatives.

  Because of the high cost of elections and the short two-year term of office, members of the House campaign almost constantly. They spend much of their time raisingcampaign funds, and they frequently return to their districts to keep in touch with voters. Because the elections are so frequent, House members tend to pay closeattention to how their votes in Congress will be seen in the short term. House members tend to come from wealthier family backgrounds than average Americans. Few working class...

• Acétylcholine : Neurotransmetteur libéré par les terminaisons des nerfs moteurs et des fibres du système nerveux parasympathique. Achondrite : Météorite...

  Acétylcholine : Neurotransmetteur libéré par les terminaisons des nerfs moteurs et des fibres du système nerveux parasympathique. Achondrite : Météorite différenciée de nature silicatée. Acide désoxyribonucléique : Macromolécule faite de nucléotides (le sucre est le désoxyribose), constiturive de la chromatine du noyau et servant de support aux caractères héréditaires. Acide gamma-aminobutyrique (GABA) : Neurotransmetteur de certaines synapses inhibitrices. Acide urique : Produit de la dégradati...

• Hinduism.

  they do not share any basic terms. B Sanātana Dharma Evidence from inscriptions indicates that Hindus had begun to use the word dharma for their religion by the 7th century. After other religions of Indian origin also began to use this term, Hindus then adopted the expression san ātana dharma to distinguish their dharma from others. The word san ātana, meaning immemorial as well as eternal, emphasized the unbroken continuity of the Hindu tradition in contrast to the other dharmas . The Bu...

• Canadian Pacific Railway - Canadian History.

  roads constructed inland from the lakeshore. However, this changed with the outbreak in Saskatchewan of the Northwest Rebellion by Louis Riel and his supportersagainst the authority of the Canadian government in March 1885. Despite the fact that the railway was not completed, a contingent of troops was able to reachWinnipeg from Montréal in only seven days, much faster than they could have gone overland, and get from there to Saskatchewan in time to successfully put down therebellion. This actio...

• Rakete - Astronomie.

  mit dem festen Brennstoff. Der flüssige Oxidator wird über ein Regelventil und eine Einspritzdüse in die Brennkammer eingespritzt. Mit diesem System werden die Vorteileder festen Treibstoffe (einfache Handhabung) mit denen der Flüssigkeiten vereint. Mit Hilfe des Regelventils lässt sich die Flüssigkeitszufuhr und damit dasVerbrennungstempo regulieren oder sogar stoppen, wenn es erforderlich ist. 4 ALLGEMEINER AUFBAU EINER DÜSE Um eine möglichst hohe Schubleistung und damit hohe Geschwindigkeit...

• Democratic Republic of the Congo - country.

  Except in the high elevations, the country’s climate is very hot and humid. The average annual temperature in the low central area is about 27°C (about 80°F).Temperatures are considerably higher in February, the hottest month. At altitudes above about 1,500 m (about 5,000 ft) the average annual temperature is about 19°C(about 66°F). Average annual rainfall is about 1,500 mm (about 60 in) in the north and about 1,300 mm (about 50 in) in the south. Frequent heavy rains occur fromApril to November...

• 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...