156 résultats pour "theory"

• Communism .

  In Britain, Robert Owen, a philanthropic Welsh manufacturer, strove against the social problems brought about by the Industrial Revolution and sought to improve thewelfare of workers. As manager of a cotton mill, he enhanced the environment of his workers by improving their housing, modernizing mill equipment for greater safetyand sanitation, and establishing low-priced stores for the workers and schools for their children. Owen believed that workers, rather than governments, should createthe in...

• First Americans.

  bones and artifacts helped 19th-century archaeologists establish the age of ancient human encampments in Europe. Yet, search as they might, American archaeologists found no comparable evidence of a Pleistocene-era human presence. But several sites revealed stone artifacts thatsome scholars believed looked similar to the ancient stone tools found in Europe. On the basis of this similarity, these experts claimed the American artifacts must be asold. By the 1890s, however, other scholars had challe...

• First Americans - Canadian History.

  bones and artifacts helped 19th-century archaeologists establish the age of ancient human encampments in Europe. Yet, search as they might, American archaeologists found no comparable evidence of a Pleistocene-era human presence. But several sites revealed stone artifacts thatsome scholars believed looked similar to the ancient stone tools found in Europe. On the basis of this similarity, these experts claimed the American artifacts must be asold. By the 1890s, however, other scholars had challe...

• Commonsensism

  2 Critical commonsensism: a systematic treatment ‘The slogans are impressive enough, ' one may say, ‘but how are they to be applied? ' In setting out, one presupposes that, by contemplating various possible beliefs, we can find out that some of them logically imply others, that some contradict others, that some are such that they serve to confirm others (they make the others probable) and that some are such as to disconfirm others (they make the others improbable). Probability, as Peirce con...

• Dark Matter - astronomy.

  observed, and the measured frequency of such events has placed limits on how much dark matter can take the form of MACHOs. From the observations that have beenmade by astronomers, it is now known that MACHOs cannot be the dominant constituent of dark matter. There are simply not enough such gravitational lenses. Physicists suspect that a more exotic form of cold dark matter must exist. This form is not baryonic. Like neutrinos, this form barely interacts with ordinary matter, butis some type of...

• Aging - biology.

  Different theories have been proposed to explain how SF works. One theory is based on the assumption that aging, and diseases that occur more frequently withadvancing age, are caused by structural damage to cells. This damage accumulates in tiny amounts each time the cell divides, eventually preventing the cell fromcarrying out normal functions. One cause of this damage may be free radicals, which are chemical compounds found in the environment and also generated by normal chemical reactions in...

• Inorganic Chemistry - chemistry.

  two electrically charged plates (positively charged top plate and negatively charged bottom plate). By measuring the difference in how fast these electron-laden oildrops fell when the metal plates were charged and uncharged, Millikan was able to calculate the total charge on each oil drop. Because each measurement was a wholenumber multiple of -1.60 × 10 -19 coulombs, Millikan concluded this was the charge carried by a single electron. Using Thomson’s electron charge-to-mass ratio, Millikan then...

• Russian Revolutions of 1917 (Histoire) .

  as Marxists. They believed that the working class—with its struggles to organize trade unions and to bring about political reforms of benefit to the majority ofpeople—would become the primary force for revolutionary change. The Russian Marxists formed the Russian Social Democratic Labor Party (RSDLP) in 1898. By 1903,however, the RSDLP had split into two factions. The faction called the Bolsheviks (from the Russian word for “majority”), led by Vladimir Ilich Lenin, favored a more centralized a...

• Africa.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• Africa - Geography.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• 1983, « A Critical Examination of the Theory that the Right to the Throne of Ancient Egypt Passed Through the Female Line in the 18th Dynasty », GM 62, 67-78.

  1977-1978, «Ahhotep Iand Ahhotep II», Serapis 4,31-40. Jean ROUSSEAU 1988, «Les calendriers deDjoser »,DE 11, 73-86. Georges Roux 1985, LaMésopotamie. Essaid'histoire politique, économique etculturelle ,Paris, Seuil. RSO =Rivista degliStudi Orientali, Rome. Gerhard RÜHLMANN 1971, «Deine Feinde fallenunterdeinen Sohlen :Bemerkungen zueinem altorientalischen Machtsymbol», WZU Halle 20,61-84. Edna R.RUSSMANN 1974, TheRepresentation ofthe King, XXVth Dynasty, Bruxelles. 1979, «Some Reflections onthe...

• La Psychiatrie est elle une science?

  distinguish science from non-science. Philosophers of science now generally agree that the search for a demarcation criterion has failed. However, in other disciplines the search for a means of distinguishing science from pseudoscience continues. I review the current debate in psychology and psychiatry. Then, returning to philosophical work, I discuss and support accounts according to which 'science' is best considered a family resemblance term. This suggests that whether psychiatric research is...

• Prokaryote - biology.

  earliest organisms to evolve, an estimated 3.4 billion to 3.5 billion years ago. The environment of the early Earth lacked oxygen, and cyanobacteria probably usedfermentation (a chemical process performed without the presence of oxygen) to produce the energy molecule adenosine triphosphate (ATP). Cyanobacteria introduced oxygen into the atmosphere through the process of photosynthesis. As the oxygen content in the atmosphere increased over the centuries, bacteria evolved that usedthis oxygen in...

• Community and communitarianism

  makes fundamental ethical criticism's of one's own community impossible. The success of communitarianism as a political theory depends upon whether it can be demonstrated that liberal political institutions cannot provide adequate conditions for the flourishing of community or secure appropriate support for persons' identities so far as their identities are determined by their membership in communities. 1 Community If I am a member of a community, I conceive of the goals and values I shar...

• Computer Science.

  theoretical research is called algorithmic complexity. Computer scientists in this field seek to develop techniques for determining the inherent efficiency of algorithmswith respect to one another. Another area of theoretical research called computability theory seeks to identify the inherent limits of computation. Software engineers use programming languages to communicate algorithms to a computer. Natural languages such as English are ambiguous—meaning that theirgrammatical structure and vocab...

• Depression (psychology).

  IV CAUSES Some depressions seem to come out of the blue, even when things are going well. Others seem to have an obvious cause: a marital conflict, financial difficulty, or somepersonal failure. Yet many people with these problems do not become deeply depressed. Most psychologists believe depression results from an interaction betweenstressful life events and a person’s biological and psychological vulnerabilities. A Biological Factors Depression runs in families. By studying twins, researche...

• Neptune (planet) - astronomy.

  The gaseous atmosphere of Neptune contains hydrogen, helium, and about 3 percent methane. It extends about 5,000 km (about 3,000 mi) above the planet’s ocean.Light reflected from Neptune’s deep atmosphere is blue, because the atmospheric methane absorbs red and orange light but scatters blue light. In 1998 astronomersalso identified molecules of methyl in Neptune’s atmosphere. Methyl molecules each contain one carbon atom and three hydrogen atoms. Methyl molecules are knownas hydrocarbon radical...

• Culture.

  form of knowledge, such as scientific discoveries; objects, such as works of art; and traditions, such as the observance of holidays. C1 Ethnocentrism and Cultural Relativism Self-identity usually depends on culture to such a great extent that immersion in a very different culture—with which a person does not share common ways of life orbeliefs—can cause a feeling of confusion and disorientation. Anthropologists refer to this phenomenon as culture shock. In multicultural societies —societies s...

• Astronomy - astronomy.

  Telescopes may use either lenses or mirrors to gather visible light, permitting direct observation or photographic recording of distant objects. Those that use lenses arecalled refracting telescopes, since they use the property of refraction, or bending, of light ( see Optics: Reflection and Refraction ). The largest refracting telescope is the 40-in (1-m) telescope at the Yerkes Observatory in Williams Bay, Wisconsin, founded in the late 19th century. Lenses bend different colors of light by d...

• Criminal Law.

  for rehabilitative treatment for the offender. On the other hand, the goals of punishment may at times conflict. The retributive and deterrence theories call for theinfliction of unpleasant experiences upon the criminal, including harsh prison treatment; but the prison environment may not be conducive to, or may even defeat,rehabilitation. No one theory of punishment addresses all the goals of criminal law. A combination of theories and goals plays a part in the thinking of the legislators who e...

• Karl Marx I INTRODUCTION Karl Marx (1818-1883), German political philosopher and revolutionary, the most important of all socialist thinkers and the creator of a system of thought called Marxism.

  his death, were revived in the 20th century by Vladimir Ilich Lenin, who developed and applied them. They became the core of the theory and practice of Bolshevismand the Third International. Marx’s ideas, as interpreted by Lenin, continued to have influence throughout most of the 20th century. In much of the world, includingAfrica and South America, emerging nations were formed by leaders who claimed to represent the proletariat. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. A...

• Karl Marx.

  his death, were revived in the 20th century by Vladimir Ilich Lenin, who developed and applied them. They became the core of the theory and practice of Bolshevismand the Third International. Marx’s ideas, as interpreted by Lenin, continued to have influence throughout most of the 20th century. In much of the world, includingAfrica and South America, emerging nations were formed by leaders who claimed to represent the proletariat. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. A...

• Church, Alonzo

  principal expression of this language is an abstraction operator which is used to construct an expression for a function from an expression for an arbitrary value. For example, ' ¸x:x 2 ' denotes the function which takes any number to its square. The rules of transformation (conversion) of the calculus provide a guide for derivations among expressions of the above type. The ¸-calculus has had a significant effect on the development of logic. It was shown that the original formulation of the...

• Quark I INTRODUCTION Quark, smallest known building block of matter.

  Constituents of MatterMatter is composed of tiny particles called quarks. Quarks come in six varieties: up (u), down (d), charm (c), strange (s),top (t), and bottom (b). Quarks also have antimatter counterparts called antiquarks (designated by a line over the lettersymbol). Quarks combine to form larger particles called baryons, and quarks and antiquarks combine to form mesons.Protons and neutrons, particles that form the nuclei of atoms, are examples of baryons. Positive and negative kaons aree...

• Encyclopedia of Philosophy: Ailly, Pierre d'

  empirical facts rather than metaphysical assumptions. Thus, it is not by chance that two of d'Ailly's favourite phrases in his philosophical writings are docet experientia (experience teaches) and patet inductive (this is clear on the basis of induction). His main sources are William of Ockham , Thomas Bradwardine , Gregory of Rimini and John Buridan , among whom Ockham is clearly the foremost authority: ‘a few things said by him I value more highly than many volumes by certain others...

• Encyclopedia of Philosophy: Alchemy

  to enrol themselves in the philosophical tradition, albeit awkwardly. Texts were attributed to pagan gods,mythological and biblical figures, ancient and medieval philosophers. Such attributions assured secrecy, while raisingthe prestige of writings of obscure authors; they might even be a subtle indication of affiliation. 4 Alchemical doctrines The basic idea of alchemy is the identity of nature and first matter as a dynamic unity: elements can pass one into another, in a circular mo...

• Les principales dates de l'Histoire de la Génétique

  1877 Fleming visualise les chromosomes 1882 August Weismann observe la distinction entre des cellules somatiques et\ les cellules germinales; chromosomes observed by Walther Flemming in the nuclei of di\ viding salamander cells. He uses the word mitosis 1887 A Weismann postulates the reduction of chromosome number in germ cells 1888 W Waldeyer coins the word chromosome 1889 Johann Miescher isolates DNA from salmon sperm; F Galton publishes Natural Inheritance (biometry) 1892 A Wei...

• Isaac NewtonIINTRODUCTIONIsaac Newton (1642-1727), English physicist, mathematician, and natural philosopher, considered one of the most important scientists of all time.

  B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the...

• Isaac Newton.

  B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the t...

• Confucian philosophy, Chinese

  occupies a pre-eminent place in the history of Chinese philosophy. The core of Confucian thought lies in the teachings of Confucius (551-479 BC) contained in the Analects ( Lunyu ), along with the brilliant and divergent contributions of Mencius (372?-289 BC) and Xunzi ( fl. 298-238 BC), as well as the Daxue (Great Learning) and the Zhongyong (Doctrine of the Mean), originally chapters in the Liji (Book of Rites). Significant and original developments, particularly along a quasi-metaphysica...

• Psychotherapy.

  Other managed-care companies pay therapists a set fee to meet with a client for up to a specified maximum number of sessions depending on the nature of theproblem, free of interference from case reviewers. For example, a managed-care firm may pay a therapist $200 to hold up to eight sessions with a person. If the clientuses all eight sessions, the therapist normally loses money. But if treatment stops after two or three sessions, the therapist makes a profit. This relatively new system iscontrov...

• Post-modernisme et le paradigme du Consensus

  consensus and neodialectic narrative. The premise of pretextual discourse implies that the significance of the observer is deconstruction. In a sense, the economy, and some would say the dialectic, of conceptual feminism depicted in Spelling's Models, Inc. is also evident in Charmed. Lyotard uses the term 'pretextual discourse' to denote the bridge between narrativity and class. Therefore, the characteristic theme of Porter's[5] model of capitalist prepatriarchial theory is the economy of postdi...

• Architecture, aesthetics of

  accounts of the geometrical discoveries of Plato and Pythagoras. He cites the latter's famous triangle theorem andadds, 'When Pythagoras discovered this fact, he had no doubt that the Muses had guided him… and it is said thathe very gratefully offered sacrifice' ( 1914: 253 ). AlthoughVitruvius is concerned with the practical applications of the theorem, mention of Pythagoras and the occult nature of his discovery expressed the common view thatperceptible forms are underwritten by an a...

• Bodin, Jean

  and doctrine contradicted Bodin's long-standing principles of legitimacy, non-resistance and religious tolerance. Yet Bodin, like many other royalist magistrates of the time, openly collaborated with the League. He sought to justify his course by mystical reflections on the preordained doom of the ruling dynasty. But he seems to have been driven by fears not only for his office and his property, but perhaps for his life as well; now, as in the past, he was under suspicion of heresy. He stood...

• Belief

  thought of as a relation to a proposition. A proposition is what is expressed by a sentence; it is what is in common between sentences in French and English that mean the same; the proposition expressed is what is grasped when you understand a sentence. Monolingual speakers believe alike by believing the same propositions; dogs have beliefs by virtue of believing propositions despite not having a language to express them; someone who believes that the sentence 'The Devil exists' is true whil...

• Applied ethics

  rule, while benefiting from the fact that everyone else is following it (see Universalism in ethics ). The applied ethicist, like the theoretical moral philosopher, must find a way to deal with this problem, but for the appliedethicist, the problem is bound up with the need to employ what is sometimes called moral casuistry. This ancientscience is not necessarily to be despised, for while a secondary meaning of the term ‘casuist' is indeed ‘sophist' or‘quibbler', it was not or...

• American philosophy in the 18th and 19th centuries

  1888), Frederick Henry Hedge (1805-90), George Ripley (1802-80), Ralph Waldo Emerson (1803-82), Margaret Fuller(1810-50) and Henry David Thoreau (1817-62). Among these, Emerson and Thoreau stand out for their power aswriters, and for their influence on such subsequent philosophers as James, Dewey, Nietzsche, and Ghandi. Emerson enjoyed a highly visible career as a lecturer and writer. His sources include the classical philosophy he studied atHarvard, English and German Romantic poetry and philo...

• Complex Numbers I INTRODUCTION Complex Numbers, in mathematics, the sum of a real number and an imaginary number.

  sometimes referred to as an Argand diagram. If a complex number in the plane is thought of as a vector joining the origin to that point, then addition of complexnumbers corresponds to standard vector addition. Figure 1 shows the complex number 3 + 2 i obtained by adding the vectors 1 + 4 i and 2 - 2 i. Figure 1: Complex Plane in Cartesian CoordinatesThis graph illustrates the addition of two complex numbers by using vectors in the complex plane with cartesiancoordinates. The parallelogram shows...

• Eukaryote - biology.

  The waste is then expelled through a hole in the fused membrane. In complex animals, cells generate wastes such as urea when nutrients are broken down within cells.These wastes are transported by blood to the kidneys. The kidneys process the waste and produce urine, which is removed from the body through the bladder.Undigested food travels through the tubelike intestines and is eliminated through the digestive system. V EVOLUTIONARY ORIGINS Eukaryotes evolved much later than prokaryotes, whose...

• Communism

  access to, resources, but the underlying principle is quite similar. Rather than freeing some or even all people in a society to devote themselves to a higher cause, secular communism is designed to allow everyone to pursue personal fulfilment. It may best be characterized by a slogan adopted by Marx that appears to have been first published on the title page of Cabet's Voyage en Icarie (1840): ‘From each according to his ability, to each according to his need' . In other words, each pers...

• Physiology.

  III RECENT ADVANCES Among the most important advances of the 20th century are the discovery of new hormones; recognition of the role of vitamins; discovery of blood types; developmentof the electrocardiograph and electroencephalograph, to record the activity of the heart and brain; discovery of the cause and cure of pernicious anemia by GeorgeRichards Minot, William Parry Murphy, and George Hoyt Whipple, all American physicians; and greater understanding of metabolism, the role of enzymes, and...

• Homer I INTRODUCTION Homer, the name traditionally assigned to the author of the Iliad and the Odyssey, the two major epics that have survived from Greek antiquity.

  Apollo ), and some have argued that portions of the texts, such as the concluding scenes of the Odyssey, were added by another hand. However, they generally believed that Homer was a poet (or at most, a pair of poets) much like the poets they knew from their own experience. They believed that the Iliad and the Odyssey, although based on traditional materials, were independent, original, and largely fictional. In the last 200 years, however, this view has changed radically, following the emer...

• Homer.

  Apollo ), and some have argued that portions of the texts, such as the concluding scenes of the Odyssey, were added by another hand. However, they generally believed that Homer was a poet (or at most, a pair of poets) much like the poets they knew from their own experience. They believed that the Iliad and the Odyssey, although based on traditional materials, were independent, original, and largely fictional. In the last 200 years, however, this view has changed radically, following the emer...

• Unemployment.

  set up to monitor the economy and provide advice to the president and Congress. Between 1945 and 1990 nine cyclical swings in unemployment occurred; all weresmaller than the 1930s depression. During this period the unemployment rate was as low as 2.9 percent (1953) and as high as 9.7 percent (1982). Because of cutbacksin the unemployment insurance program and changes in the nature of employment during the 1980s, however, only 37 percent of jobless workers received benefits in1990. Fears that the...

• Ancient Egypt - history.

  The Nile River runs through the ancient city of Thebes in eastern Egypt. For a time, beginning in 2040 bc, Thebes was the capital ofEgypt.Farrell Grehan/Photo Researchers, Inc. According to inscriptions and documents found by archaeologists, the Egyptians called their country Kemet, meaning “the Black Land,” a reference to the dark, fertile soil that remained after the Nile floodwaters had receded. They also used another term, Deshret, or “the Red Land,” a designation for the desert sands th...

• Artificial Intelligence.

  Work in AI has primarily focused on two broad areas: developing logic-based systems that perform common-sense and expert reasoning, and using cognitive andbiological models to simulate and explain the information-processing capabilities of the human brain. In general, work in AI can be categorized within three research anddevelopment types: symbolic, connectionist, and evolutionary. Each has characteristic strengths and weaknesses. A Symbolic AI Symbolic AI is based in logic. It uses sequences...

• Igneous Rock.

  As a magma cools, the first crystals to form will be of minerals that become solid at relatively high temperatures (usually olivine and a type of feldspar known asanorthite). The composition of these early-formed mineral crystals will be different from the initial composition of the magma. Consequently, as these growing crystalstake certain elements out of the magma in certain proportions, the composition of the remaining liquid changes. This process is known as magmatic differentiation.Sometime...

• Poliomyelitis.

  Physical therapy helps patients with paralytic polio stretch and move affected muscles. This movement minimizes the atrophy, or shrinkage, of affected muscles andlimbs and builds strength. Exercises can also retrain working muscles to compensate for other muscles that have permanently lost the ability to move. Rehabilitativetherapy trains patients to use braces, crutches, and other devices that provide support and aid mobility. V PREVENTION OF POLIO Immunization with polio vaccine is the best w...

• Radioactivity I 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...

• Volcano.

  before eruption. Very violent explosive eruptions are called Plinian eruptions, after Roman naturalist Pliny the Elder. These eruptions can last for several hours to daysand eject a large amount of pyroclastic material. Some volcanoes can produce much more energetic eruptions that eject materials farther from the vents because oftheir andesitic and dacitic composition. Andesitic and dacitic lava is generally thicker than basaltic lava. Stiff lava generally produces more-explosive eruptions. B No...