title: Community content: It considers how such interactions, along with interactions between species and the abiotic environment, affect community structure and species richness, diversity and patterns of abundance. Species interact in three ways: competition, predation and mutualism. Competition typically results in a double negative—that is both species lose in the interaction. Predation is a win/lose situation with one species winning. Mutualism, on the other hand, involves both species cooperating in some way, with both winning. The two main types of communities are major which are self-sustaining and self-regulating (such as a forest or a lake) and minor communities which rely on other communities


title: Community content: (like fungi decomposing a log) and are the building blocks of major communities. In "Gemeinschaft und Gesellschaft" (1887), German sociologist Ferdinand Tönnies described two types of human association: "Gemeinschaft" (usually translated as "community") and "Gesellschaft" ("society" or "association"). Tönnies proposed the "Gemeinschaft–Gesellschaft" dichotomy as a way to think about social ties. No group is exclusively one or the other. "Gemeinschaft" stress personal social interactions, and the roles, values, and beliefs based on such interactions. "Gesellschaft" stress indirect interactions, impersonal roles, formal values, and beliefs based on such interactions. In a seminal 1986 study, McMillan and Chavis identify four elements of


title: Community content: "sense of community": A "sense of community index" (SCI) was developed by Chavis and colleagues, and revised and adapted by others. Although originally designed to assess sense of community in neighborhoods, the index has been adapted for use in schools, the workplace, and a variety of types of communities. Studies conducted by the APPA indicate that young adults who feel a sense of belonging in a community, particularly small communities, develop fewer psychiatric and depressive disorders than those who do not have the feeling of love and belonging. The process of learning to adopt the behavior patterns of the community


title: Community content: is called socialization. The most fertile time of socialization is usually the early stages of life, during which individuals develop the skills and knowledge and learn the roles necessary to function within their culture and social environment. For some psychologists, especially those in the psychodynamic tradition, the most important period of socialization is between the ages of one and ten. But socialization also includes adults moving into a significantly different environment, where they must learn a new set of behaviors. Socialization is influenced primarily by the family, through which children first learn community norms. Other important influences include schools, peer


title: Community content: groups, people, mass media, the workplace, and government. The degree to which the norms of a particular society or community are adopted determines one's willingness to engage with others. The norms of tolerance, reciprocity, and trust are important "habits of the heart," as de Tocqueville put it, in an individual's involvement in community. Community development is often linked with community work or community planning, and may involve stakeholders, foundations, governments, or contracted entities including non-government organisations (NGOs), universities or government agencies to progress the social well-being of local, regional and, sometimes, national communities. More grassroots efforts, called community building or


title: Community content: community organizing, seek to empower individuals and groups of people by providing them with the skills they need to effect change in their own communities. These skills often assist in building political power through the formation of large social groups working for a common agenda. Community development practitioners must understand both how to work with individuals and how to affect communities' positions within the context of larger social institutions. Public administrators, in contrast, need to understand community development in the context of rural and urban development, housing and economic development, and community, organizational and business development. Formal accredited programs conducted


title: "Charles Babbage" content: Charles Babbage Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer. Considered by some to be a "father of the computer", Babbage is credited with inventing the first mechanical computer that eventually led to more complex electronic designs, though all the essential ideas of modern computers are to be found in Babbage's analytical engine. His varied work in other fields has led him to be described as "pre-eminent" among the many polymaths of his century. Parts of Babbage's incomplete


title: "Charles Babbage" content: mechanisms are on display in the Science Museum in London. In 1991, a functioning difference engine was constructed from Babbage's original plans. Built to tolerances achievable in the 19th century, the success of the finished engine indicated that Babbage's machine would have worked. Babbage's birthplace is disputed, but according to the "Oxford Dictionary of National Biography" he was most likely born at 44 Crosby Row, Walworth Road, London, England. A blue plaque on the junction of Larcom Street and Walworth Road commemorates the event. His date of birth was given in his obituary in "The Times" as 26 December 1792;


title: "Charles Babbage" content: but then a nephew wrote to say that Babbage was born one year earlier, in 1791. The parish register of St. Mary's, Newington, London, shows that Babbage was baptised on 6 January 1792, supporting a birth year of 1791. Babbage was one of four children of Benjamin Babbage and Betsy Plumleigh Teape. His father was a banking partner of William Praed in founding Praed's & Co. of Fleet Street, London, in 1801. In 1808, the Babbage family moved into the old Rowdens house in East Teignmouth. Around the age of eight, Babbage was sent to a country school in Alphington


title: "Charles Babbage" content: Joseph Whitworth. Through the Royal Society Babbage acquired the friendship of the engineer Marc Brunel. It was through Brunel that Babbage knew of Joseph Clement, and so came to encounter the artisans whom he observed in his work on manufactures. Babbage provided an introduction for Isambard Kingdom Brunel in 1830, for a contact with the proposed Bristol & Birmingham Railway. He carried out studies, around 1838, to show the superiority of the broad gauge for railways, used by Brunel's Great Western Railway. In 1838, Babbage invented the pilot (also called a cow-catcher), the metal frame attached to the front of


title: "Charles Babbage" content: of the original is also available. Half of Babbage's brain is preserved at the Hunterian Museum in the Royal College of Surgeons in London. The other half of Babbage's brain is on display in the Science Museum, London. There is a black plaque commemorating the 40 years Babbage spent at 1 Dorset Street, London. Locations, institutions and other things named after Babbage include: Babbage frequently appears in steampunk works; he has been called an iconic figure of the genre. Other works in which Babbage appears include: Charles Babbage Charles Babbage (; 26 December 1791 – 18 October 1871) was an


title: Coma content: signs, a general portion dedicated to making observations about the patient's respiration (breathing pattern), body movements (if any), and of the patient's body habitus (physique); it should also include assessment of the brainstem and cortical function through special reflex tests such as the oculocephalic reflex test (doll's eyes test), oculovestibular reflex test (cold caloric test), nasal tickle, corneal reflex, and the gag reflex. Vital signs in medicine are temperature (rectal is most accurate), blood pressure, heart rate (pulse), respiratory rate, and oxygen saturation. It should be easy to evaluate these vitals quickly to gain insight into a patient's metabolism, fluid


title: Coma content: (CN VII), and cranial nerve number 5 (CN V). Cranial nerve number 5 (CN V), and its ophthalmic branch (V) are responsible for the afferent arm of the reflex, and the cranial nerve number 7 (CN VII) also known a facial nerve, is responsible for the efferent arm, causing contraction of the muscle orbicularis oculi resulting in closing of the eyes. Pupil assessment is often a critical portion of a comatose examination, as it can give information as to the cause of the coma; the following table is a technical, medical guideline for common pupil findings and their possible interpretations:


title: Coma content: preventing infections such as pneumonias, bedsores (decubitus ulcers), and providing balanced nutrition. Infections may appear from the patient not being able to move around, and being confined to the bed. The nursing staff moves the patient every 2–3 hours from side to side and depending on the state of consciousness sometimes to a chair. The goal is to move the patient as much as possible to try to avoid bedsores, atelectasis and pneumonia. Pneumonia can occur from the person’s inability to swallow leading to aspiration, lack of gag reflex or from feeding tube, (aspiration pneumonia). Physical therapy may also be


title: "Çatalhöyük" content: significant amounts of wood ash. In good weather, many daily activities may also have taken place on the rooftops, which may have formed a plaza. In later periods, large communal ovens appear to have been built on these rooftops. Over time, houses were renewed by partial demolition and rebuilding on a foundation of rubble, which was how the mound was gradually built up. As many as eighteen levels of settlement have been uncovered. As a part of ritual life, the people of Çatalhöyük buried their dead within the village. Human remains have been found in pits beneath the floors and,


title: Catullus content: of art. Catullus described his work as "expolitum", or polished, to show that the language he used was very carefully and artistically composed. Catullus was also an admirer of Sappho, a female poet of the seventh century BC, and is the source for much of what we know or infer about her. Catullus 51 follows Sappho 31 so closely that some believe the later poem to be, in part, a direct translation of the earlier poem, and 61 and 62 are certainly inspired by and perhaps translated directly from lost works of Sappho. Both of the latter are "epithalamia", a


title: Caving content: form of eco and adventure tourism. Tour companies have established an industry leading and guiding tours into and through caves. Depending on the type of cave and the type of tour, the experience could be adventure-based or ecological-based. In many areas (e.g. America, the oceanic islands of Tenerife, Iceland and Hawaii), there are tours led through lava tubes by a guiding service. Caving has also been described as an "individualist's team sport" by some, as cavers can often make a trip without direct physical assistance from others but will generally go in a group for companionship or to provide emergency


title: Crime content: Crime In ordinary language, a crime is an unlawful act punishable by a state or other authority. The term "crime" does not, in modern criminal law, have any simple and universally accepted definition, though statutory definitions have been provided for certain purposes. The most popular view is that crime is a category created by law; in other words, something is a crime if declared as such by the relevant and applicable law. One proposed definition is that a crime or offence (or criminal offence) is an act harmful not only to some individual but also to a community, society or


title: Crime content: the state ("a public wrong"). Such acts are forbidden and punishable by law. The notion that acts such as murder, rape and theft are to be prohibited exists worldwide. What precisely is a criminal offence is defined by criminal law of each country. While many have a catalogue of crimes called the criminal code, in some common law countries no such comprehensive statute exists. The state (government) has the power to severely restrict one's liberty for committing a crime. In modern societies, there are procedures to which investigations and trials must adhere. If found guilty, an offender may be sentenced


title: Crime content: to a form of reparation such as a community sentence, or, depending on the nature of their offence, to undergo imprisonment, life imprisonment or, in some jurisdictions, execution. Usually, to be classified as a crime, the "act of doing something criminal" ("actus reus") mustwith certain exceptionsbe accompanied by the "intention to do something criminal" ("mens rea"). While every crime violates the law, not every violation of the law counts as a crime. Breaches of private law (torts and breaches of contract) are not automatically punished by the state, but can be enforced through civil procedure. When informal relationships and sanctions


title: Crime content: prove insufficient to establish and maintain a desired social order, a government or a state may impose more formalized or stricter systems of social control. With institutional and legal machinery at their disposal, agents of the State can compel populations to conform to codes and can opt to punish or attempt to reform those who do not conform. Authorities employ various mechanisms to regulate (encouraging or discouraging) certain behaviors in general. Governing or administering agencies may for example codify rules into laws, police citizens and visitors to ensure that they comply with those laws, and implement other policies and practices


title: Crime content: that legislators or administrators have prescribed with the aim of discouraging or preventing crime. In addition, authorities provide remedies and sanctions, and collectively these constitute a criminal justice system. Legal sanctions vary widely in their severity; they may include (for example) incarceration of temporary character aimed at reforming the convict. Some jurisdictions have penal codes written to inflict permanent harsh punishments: legal mutilation, capital punishment or life without parole. Usually, a natural person perpetrates a crime, but legal persons may also commit crimes. Conversely, at least under U.S. law, nonpersons such as animals cannot commit crimes. The sociologist Richard Quinney


title: Crime content: has written about the relationship between society and crime. When Quinney states "crime is a social phenomenon" he envisages both how individuals conceive crime and how populations perceive it, based on societal norms. The word "crime" is derived from the Latin root "cernō", meaning "I decide, I give judgment". Originally the Latin word "crīmen" meant "charge" or "cry of distress." The Ancient Greek word "krima" (κρίμα), from which the Latin cognate derives, typically referred to an intellectual mistake or an offense against the community, rather than a private or moral wrong. In 13th century English "crime" meant "sinfulness", according to


title: Crime content: etymonline.com. It was probably brought to England as Old French "crimne" (12th century form of Modern French "crime"), from Latin "crimen" (in the genitive case: "criminis"). In Latin, "crimen" could have signified any one of the following: "charge, indictment, accusation; crime, fault, offense". The word may derive from the Latin "cernere" – "to decide, to sift" (see crisis, mapped on Kairos and Chronos). But Ernest Klein (citing Karl Brugmann) rejects this and suggests *cri-men, which originally would have meant "cry of distress". Thomas G. Tucker suggests a root in "cry" words and refers to English plaint, plaintiff, and so on.


title: Crime content: The meaning "offense punishable by law" dates from the late 14th century. The Latin word is glossed in Old English by "facen", also "deceit, fraud, treachery", [cf. fake]. "Crime wave" is first attested in 1893 in American English. Whether a given act or omission constitutes a crime does not depend on the nature of that act or omission. It depends on the nature of the legal consequences that may follow it. An act or omission is a crime if it is capable of being followed by what are called criminal proceedings. History The following definition of "crime" was provided by


title: Crime content: the Prevention of Crimes Act 1871, and applied for the purposes of section 10 of the Prevention of Crime Act 1908: For the purpose of section 243 of the Trade Union and Labour Relations (Consolidation) Act 1992, a crime means an offence punishable on indictment, or an offence punishable on summary conviction, and for the commission of which the offender is liable under the statute making the offence punishable to be imprisoned either absolutely or at the discretion of the court as an alternative for some other punishment. A normative definition views crime as deviant behavior that violates prevailing normscultural


title: Crime content: tolerated behaviors under a state of emergency in the event of war, natural disaster or civil unrest. Undesired activities at such times may include assembly in the streets, violation of curfew, or possession of firearms. Two common types of employee crime exist: embezzlement and wage theft. The complexity and anonymity of computer systems may help criminal employees camouflage their operations. The victims of the most costly scams include banks, brokerage houses, insurance companies, and other large financial institutions. In the United States, it is estimated that workers are not paid at least $19 billion every year in overtime and that


title: Celebrity content: small percentage achieve fame and fortune. Outside of the sports and entertainment sphere, the top inventors, professionals such as doctors, lawyers, and scientists, etc. are unlikely to become celebrities even if they are enormously successful in their field due to society's disinterest in science, invention, medicine, and courtroom law which is not fictional. American microbiologist Maurice Hilleman is credited with saving more lives than any other medical scientist of the 20th century. After Hilleman's death Ralph Nader wrote, "Yet almost no one knew about him, saw him on television, or read about him in newspapers or magazines. His anonymity, in


title: "Complex number" content: single variable have a solution in complex numbers. Formally, the complex number system can be defined as the algebraic extension of the ordinary real numbers by an imaginary number . This means that complex numbers can be added, subtracted, and multiplied, as polynomials in the variable , with the rule imposed. Furthermore, complex numbers can also be divided by nonzero complex numbers. Overall, the complex number system is a field. The complex numbers give rise to the fundamental theorem of algebra: every non-constant polynomial equation with complex coefficients has a complex solution. This property is true of the complex numbers,


title: "Economy of Colombia" content: as the planner and regulator within the sector. Colombia was a pioneer in promoting airlines in an effort to overcome its geographic barriers to transportation. The Colombian Company of Air Navigation, formed in 1919, was the second commercial airline in the world. It was not until the 1940s that Colombia's air transportation began growing significantly in the number of companies, passengers carried, and kilometers covered. In the early 2000s, an average of 72 percent of the passengers transported by air go to national destinations, while 28 percent travel internationally. One notable feature is that after the reforms of the beginning


title: "Foreign relations of Colombia" content: Nations, Group of 3, Group of 11, Group of 24, Group of 77, Inter-American Development Bank, International Atomic Energy Agency, International Bank for Reconstruction and Development, International Chamber of Commerce, International Civil Aviation Organization, International Criminal Police Organization, International Development Association, International Finance Corporation, International Fund for Agricultural Development, International Labour Organization, International Maritime Organization, International Maritime Satellite Organization, International Monetary Fund (IMF), International Olympic Committee, International Organization for Migration, International Organization for Standardization, International Telecommunication Union, International Telecommunications Satellite Organization, International Trade Union Confederation, Latin American Economic System, Latin American Integration Association, Non-Aligned Movement, Organization of American States (OAS),


title: "Continental Europe" content: continental part of [Italy (excluding Sardinia, Sicily, etc.), the continental part of [Spain (excluding the Balearic islands, the Canary Islands, Alboran, etc.), the continental part of France (excluding Corsica, etc.), the continental part of Portugal (excluding the Madeira and Azores islands), or the continental part of Greece (excluding the Ionian Islands, the Aegean Islands, and Crete). The term is used from the perspective of the island residents of each country to describe the continental portion of their country or the continent (or mainland) as a whole. Continental Europe Continental or mainland Europe is the continuous continent of Europe, excluding its


title: Cardiff content: an extra vote for the South Wales Central region which increases proportionality to the Assembly. The most recent Welsh Assembly general election were held on 5 May 2016. In the Assembly Cardiff is represented by Jenny Rathbone (Labour) in Cardiff Central, Julie Morgan (Labour) in Cardiff North, Vaughan Gething (Labour) in Cardiff South and Penarth and Mark Drakeford (Labour) in Cardiff West. In Westminster, Cardiff is represented by Jo Stevens (Labour) in Cardiff Central, Anna McMorrin(Labour) in Cardiff North, Stephen Doughty (Labour) in Cardiff South and Penarth and Kevin Brennan (Labour) in Cardiff West. The Welsh Government has its headquarters


title: "Capital punishment" content: Capital punishment Capital punishment, also known as the death penalty, is a government-sanctioned practice whereby a person is killed by the state as a punishment for a crime. The sentence that someone be punished in such a manner is referred to as a death sentence, whereas the act of carrying out the sentence is known as an execution. Crimes that are punishable by death are known as capital crimes or capital offences, and they commonly include offences such as murder, treason, espionage, war crimes, crimes against humanity and genocide. Etymologically, the term "capital" (lit. "of the head", derived via the


title: "Capital punishment" content: Latin ' from ', "head") in this context alluded to execution by beheading. Fifty-six countries retain capital punishment, 106 countries have completely abolished it "de jure" for all crimes, eight have abolished it for ordinary crimes (while maintaining it for special circumstances such as war crimes), and 28 are abolitionist in practice. Capital punishment is a matter of active controversy in several countries and states, and positions can vary within a single political ideology or cultural region. In the European Union, Article 2 of the Charter of Fundamental Rights of the European Union prohibits the use of capital punishment. The


title: "Capital punishment" content: Council of Europe, which has 47 member states, has sought to abolish the use of the death penalty by its members absolutely, through Protocol 13 of the European Convention on Human Rights. However, this only affects those member states which have signed and ratified it, and they do not include Armenia, Russia, and Azerbaijan. The United Nations General Assembly has adopted, in 2007, 2008, 2010, 2012 and 2014, non-binding resolutions calling for a global moratorium on executions, with a view to eventual abolition. Although most nations have abolished capital punishment, over 60% of the world's population live in countries where


title: "Capital punishment" content: the death penalty is retained, such as China, India, the United States, Indonesia, Pakistan, Bangladesh, Nigeria, Egypt, Iran, among all mostly Islamic countries, as is maintained in Japan and Sri Lanka. Execution of criminals has been used by nearly all societies since the beginning of civilizations on Earth. Until the nineteenth century, without developed prison systems, there was frequently no workable alternative to insure deterrence and incapacitation of criminals. The executions themselves often involved torture with cruel methods such as the breaking wheel. The use of formal execution extends to the beginning of recorded history. Most historical records and various


title: "Capital punishment" content: primitive tribal practices indicate that the death penalty was a part of their justice system. Communal punishment for wrongdoing generally included compensation by the wrongdoer, corporal punishment, shunning, banishment and execution. Usually, compensation and shunning were enough as a form of justice. The response to crime committed by neighbouring tribes or communities included a formal apology, compensation or blood feuds. A blood feud or vendetta occurs when arbitration between families or tribes fails or an arbitration system is non-existent. This form of justice was common before the emergence of an arbitration system based on state or organized religion. It may


title: "Capital punishment" content: and Singapore. Other crimes that are punishable by death in some countries include terrorism, treason, espionage, crimes against the state (most countries with the death penalty), political protests (Saudi Arabia), rape (China, India, Iran, Saudi Arabia, Brunei, etc.), economic crimes (China), kidnapping (China), separatism (China), adultery (Saudi Arabia, Iran, Qatar, Brunei, etc.), sodomy (Saudi Arabia, Iran, Brunei, etc.), and religious Hudud offences such as apostasy (Saudi Arabia, Iran, Sudan, etc.), blasphemy (Saudi Arabia, Iran, Pakistan), Moharebeh (Iran), Witchcraft and Sorcery (Saudi Arabia). and forms of aggravated robbery/hirabah, (Saudi Arabia, Kenya, Zambia). Capital punishment is controversial. Death penalty opponents regard the


title: "Carbon dioxide" content: from the burning of fossil fuels remains in the atmosphere and is not absorbed by vegetation and the oceans. While transparent to visible light, carbon dioxide is a greenhouse gas, absorbing and emitting infrared radiation at its two infrared-active vibrational frequencies (see the section "Structure and bonding" above). Light emission from the earth's surface is most intense in the infrared region between 200 and 2500 cm, as opposed to light emission from the much hotter sun which is most intense in the visible region. Absorption of infrared light at the vibrational frequencies of atmospheric carbon dioxide traps energy near the


title: Color content: Color Color (American English), or colour (Commonwealth English), is the characteristic of human visual perception described through color "categories", with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically


title: Color content: by coordinates, which in 1931 were also named in global agreement with internationally agreed color names like mentioned above (red, orange, etc.) by the International Commission on Illumination. The RGB color space for instance is a color space corresponding to human trichromacy and to the three cone cell types that respond to three bands of light: long wavelengths, peaking near 564–580 nm ("red"); medium-wavelength, peaking near 534–545 nm ("green"); and short-wavelength light, near 420–440 nm ("blue"). There may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the


title: Color content: dimensions relates to a color's colorfulness). The photo-receptivity of the "eyes" of other species also varies considerably from that of humans and so results in correspondingly different "color" perceptions that cannot readily be compared to one another. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red. Papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the animal kingdom has been found in stomatopods (such as the mantis shrimp) with up to 12 spectral receptor types thought to work as multiple dichromatic units.


title: Color content: The science of color is sometimes called chromatics, colorimetry, or simply color science. It includes the study of the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what is commonly referred to simply as "light"). Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 390 nm to 700 nm), it is known as "visible light". Most light


title: Color content: sources emit light at many different wavelengths; a source's "spectrum" is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color in that direction, there are many more possible spectral combinations than color sensations. In fact, one may formally define a color as a class of spectra that give rise to the same color sensation, although such classes would vary widely among different species, and to a lesser extent among individuals within the same species. In each such class the members are called "metamers" of the


title: Color content: color in question. The familiar colors of the rainbow in the spectrum—named using the Latin word for "appearance" or "apparition" by Isaac Newton in 1671—include all those colors that can be produced by visible light of a single wavelength only, the "pure spectral" or "monochromatic" colors. The table at right shows approximate frequencies (in terahertz) and wavelengths (in nanometers) for various pure spectral colors. The wavelengths listed are as measured in air or vacuum (see refractive index). The color table should not be interpreted as a definitive list—the pure spectral colors form a continuous spectrum, and how it is divided


title: Color content: into distinct colors linguistically is a matter of culture and historical contingency (although people everywhere have been shown to "perceive" colors in the same way). A common list identifies six main bands: red, orange, yellow, green, blue, and violet. Newton's conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, and that indigo was simply the dark blue of the indigo dye that was being imported at the time. The "intensity" of a spectral color, relative to the context in which


title: Color content: it is viewed, may alter its perception considerably; for example, a low-intensity orange-yellow is brown, and a low-intensity yellow-green is olive green. The color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Physically, objects can be said to have the color of the light leaving their surfaces, which normally depends on the spectrum of the incident illumination and the reflectance properties of the surface, as well as potentially on the angles of illumination and viewing. Some objects not only reflect light, but also transmit light


title: Color content: or emit light themselves, which also contributes to the color. A viewer's perception of the object's color depends not only on the spectrum of the light leaving its surface, but also on a host of contextual cues, so that color differences between objects can be discerned mostly independent of the lighting spectrum, viewing angle, etc. This effect is known as color constancy. Some generalizations of the physics can be drawn, neglecting perceptual effects for now: To summarize, the color of an object is a complex result of its surface properties, its transmission properties, and its emission properties, all of which


title: Color content: contribute to the mix of wavelengths in the light leaving the surface of the object. The perceived color is then further conditioned by the nature of the ambient illumination, and by the color properties of other objects nearby, and via other characteristics of the perceiving eye and brain. Although Aristotle and other ancient scientists had already written on the nature of light and color vision, it was not until Newton that light was identified as the source of the color sensation. In 1810, Goethe published his comprehensive "Theory of Colors" in which he ascribed physiological effects to color that are


title: Computation content: Computation Computation is any type of calculation that includes both arithmetical and non-arithmetical steps and follows a well-defined model, for example an algorithm. The study of computation is paramount to the discipline of computer science. A computation can be seen as a purely physical phenomenon occurring inside a closed physical system called a computer. Examples of such physical systems include digital computers, mechanical computers, quantum computers, DNA computers, molecular computers, microfluidics-based computers, analog computers, or wetware computers. This point of view has been adopted by the physics of computation, a branch of theoretical physics, as well as the field of


title: Computation content: natural computing. An even more radical point of view, pancomputationalism, is the postulate of digital physics that argues that the evolution of the universe is itself a computation. The classic account of computation is found throughout the works of Hilary Putnam and others. Peter Godfrey-Smith has dubbed this the "simple mapping account." Gualtiero Piccinini's summary of this account states that a physical system can be said to perform a specific computation when there is a mapping between the state of that system to the computation such that the “microphysical states [of the system] mirror the state transitions between the computational


title: Computation content: states.” Philosophers such as Jerry Fodor have suggested various accounts of computation with the restriction that semantic content be a necessary condition for computation (that is, what differentiates an arbitrary physical system from a computing system is that the operands of the computation represent something). This notion attempts to prevent the logical abstraction of the mapping account of pancomputationalism, the idea that everything can be said to be computing everything. Gualtiero Piccinini proposes an account of computation based in mechanical philosophy. It states that physical computing systems are types of mechanisms that, by design, perform physical computation, or “the manipulation


title: Computation content: (by a functional mechanism) of a medium-independent vehicle according to a rule.” Medium-independence requires that the property is able to be instantiated by multiple realizers and multiple mechanisms and that the inputs and outputs of the mechanism also be multiply realizable. In short, medium-independence allows for the use of physical variables with traits other than voltage (as in typical digital computers); this is imperative in considering other types of computation, such as that occurs in the brain or in a quantum computer. A rule, in this sense, provides a mapping among inputs, outputs, and internal states of the physical computing


title: Clown content: developed out of the zanni ""rustic fool"" characters of the early modern commedia dell'arte, which were themselves directly based on the ""rustic fool"" characters of ancient Greek and Roman theatre. Rustic buffoon characters in Classical Greek theater were known as " sklêro-paiktês" (from "paizein" "to play (like a child)") or "deikeliktas", besides other generic terms for "rustic" or "peasant". In Roman theater, a term for clown was "fossor", literally "digger; labourer". The English word "clown" was first recorded c. 1560 (as "clowne, cloyne") in the generic meaning "rustic, boor, peasant". The origin of the word is uncertain, perhaps from a


title: Clown content: character. The most influential such pair in Victorian England were the Payne Brothers, active during the 1860s and 1870s. The "white clown", or "clown blanc" from the original French, is a sophisticated character, as opposed to the clumsy auguste. They are also distinguished as the "sad clown" (blanc) and "happy clown" (auguste). The Auguste face base makeup color is a variation of pink, red, or tan rather than white. Features are exaggerated in size, and are typically red and black in color. The mouth is thickly outlined with white (called the muzzle) as are the eyes. Appropriate to the character,


title: Clown content: Baron Cohen would all fit the definition of a character clown. The character clown makeup is a comic slant on the standard human face. Their makeup starts with a flesh tone base and may make use of anything from glasses, mustaches and beards to freckles, warts, big ears or strange haircuts. The most prevalent character clown in the American circus is the "hobo", "tramp" or "bum" clown. There are subtle differences in the American character clown types. The primary differences among these clown types is attitude. According to American circus expert Hovey Burgess, they are : Clowns International claims to


title: Cycling content: Some bicycle activists (including some traffic management advisers) seek the construction of bike paths, cycle tracks and bike lanes for journeys of all lengths and point to their success in promoting safety and encouraging more people to cycle. Some activists, especially those from the vehicular cycling tradition, view the safety, practicality, and intent of such facilities with suspicion. They favor a more holistic approach based on the 4 'E's; "education" (of everyone involved), "encouragement" (to apply the education), "enforcement" (to protect the rights of others), and "engineering" (to facilitate travel while respecting every person's equal right to do so). Some


title: Carbohydrate content: informal contexts, the term "carbohydrate" often means any food that is particularly rich in the complex carbohydrate starch (such as cereals, bread and pasta) or simple carbohydrates, such as sugar (found in candy, jams, and desserts). Often in lists of nutritional information, such as the USDA National Nutrient Database, the term "carbohydrate" (or "carbohydrate by difference") is used for everything other than water, protein, fat, ash, and ethanol. This includes chemical compounds such as acetic or lactic acid, which are not normally considered carbohydrates. It also includes dietary fiber which is a carbohydrate but which does not contribute much in


title: Carbohydrate content: whole food, where fiber, vitamins and minerals are also found (as opposed to processed carbohydrates, which provide energy but few other nutrients). The standard usage, however, is to classify carbohydrates chemically: simple if they are sugars (monosaccharides and disaccharides) and complex if they are polysaccharides (or oligosaccharides). In any case, the simple vs. complex chemical distinction has little value for determining the nutritional quality of carbohydrates. Some simple carbohydrates (e.g. fructose) raise blood glucose slowly, while some complex carbohydrates (starches), especially if processed, raise blood sugar rapidly. The speed of digestion is determined by a variety of factors including which


title: "Standard works" content: Standard works The standard works of The Church of Jesus Christ of Latter-day Saints (LDS Church) are the four books that currently constitute its open scriptural canon. (The scriptural canon is "open" due to the LDS belief in continuous revelation. Additions can be made to the scriptural canon with the "common consent" of the church's membership.) The four books of the standard works are: The standard works are printed and distributed by the LDS Church both in a single binding called a "quadruple combination" and as a set of two books, with the Bible in one binding, and the other


title: "Standard works" content: three books in a second binding called a "triple combination". Current editions of the standard works include a number of non-canonical study aids, including a Bible dictionary, photographs, maps and gazetteer, topical guide, index, footnotes, cross references, and excerpts from the Joseph Smith Translation of the Bible (JST). Under the LDS Church's doctrine of continuing revelation, Latter-day Saints believe in the principle of revelation from God to his children. Individual members are entitled to divine revelation for confirmation of truths, gaining knowledge or wisdom, meeting personal challenges, and so forth. Parents are entitled to revelation for raising their families. Divine


title: "Standard works" content: revelation for the direction of the entire church comes from God to the President of the Church, who is considered to be a prophet by Latter-day Saints in the same sense as Noah, Abraham, Moses, Peter, and other biblical leaders. When prophets and general authorities of the church speak as "moved upon by the Holy Ghost", it "shall be scripture, shall be the will of the Lord, shall be the mind of the Lord, shall be the word of the Lord, shall be the voice of the Lord, and the power of God unto salvation." Members are encouraged to ponder


title: "Standard works" content: these revelations and pray to determine for themselves the truthfulness of doctrine. The Doctrine and Covenants teaches that "all things must be done in order, and by common consent in the church."(). This applies to adding new scripture. LDS Church president Harold B. Lee taught "The only one authorized to bring forth any new doctrine is the President of the Church, who, when he does, will declare it as revelation from God, and it will be so accepted by the Council of the Twelve and sustained by the body of the Church." There are several instances of this happening in


title: "Standard works" content: the LDS Church: When a doctrine undergoes this procedure, the LDS Church treats it as the word of God, and it is used as a standard to compare other doctrines. Lee taught: It is not to be thought that every word spoken by the General Authorities is inspired, or that they are moved upon by the Holy Ghost in everything they speak and write. Now you keep that in mind. I don't care what his position is, if he writes something or speaks something that goes beyond anything that you can find in the standard works, unless that one be


title: "Standard works" content: the prophet, seer, and revelator—please note that one exception—you may immediately say, "Well, that is his own idea!" And if he says something that contradicts what is found in the standard works (I think that is why we call them "standard"—it is the standard measure of all that men teach), you may know by that same token that it is false; regardless of the position of the man who says it. English-speaking Latter-day Saints typically study the LDS Church-published edition of the King James Version of the Bible (KJV), which includes LDS-oriented chapter headings, footnotes referencing books in the Standard


title: "Standard works" content: Works, and select passages from the Joseph Smith Translation of the Bible. Though the KJV was always commonly used, it was officially adopted in the 1950s when J. Reuben Clark, of the church's First Presidency, argued extensively that newer translations, such as Revised Standard Version of 1952, were of lower quality and less compatible with LDS tradition. After publishing its own edition in 1979, the First Presidency announced in 1992 that the KJV was the church's official English Bible, stating "[w]hile other Bible versions may be easier to read than the King James Version, in doctrinal matters latter-day revelation supports


title: "Standard works" content: the King James Version in preference to other English translations." In 2010 this was written into the church's "Handbook", which directs official church policy and programs. A Spanish version, with a similar format and using a slightly revised version of the 1909 Reina-Valera translation, was published in 2009. Latter-day Saints in other non-English speaking areas may use other versions of the Bible. Though the Bible is part of the LDS canon and members believe it to be the word of God, they believe that omissions and mistranslations are present in even the earliest known manuscripts. They claim that the errors


title: "Standard works" content: in the Bible have led to incorrect interpretations of certain passages. Thus, as church founder Joseph Smith explained, the church believes the Bible to be the word of God "as far as it is translated correctly." The church teaches that "[t]he most reliable way to measure the accuracy of any biblical passage is not by comparing different texts, but by comparison with the Book of Mormon and modern-day revelations". The manuscripts of the Joseph Smith Translation of the Bible state that "the Song of Solomon is not inspired scripture," and therefore it is not included in LDS canon and rarely


title: "Standard works" content: studied by members of the LDS Church. However, it is still printed in every version of the King James Bible published by the church. Although the Apocrypha was part of the 1611 edition of the KJV, the LDS Church does not currently use the Apocrypha as part of its canon. Joseph Smith taught that while the contemporary edition of the Apocrypha was not to be relied on for doctrine, it was potentially useful when read with a spirit of discernment. Joseph Smith translated selected verses of the Bible, working by subject. Smith did not complete the entire text of the


title: "Columbus, Ohio" content: Veritas Community Church, the Indianola Church of Christ, the Greek Orthodox Church's Annunciation Cathedral, North Columbus Friends Meeting (Quaker), The Church of Jesus Christ of Latter-day Saints Columbus Ohio Temple, Russian Baptist Church of Columbus (in Dublin, OH), the Ahlul Bayt Islamic Center, the Muslim Noor Islamic Cultural Center, Beth Jacob Synagogue (Orthodox Jewish) and the Reform Jewish Temple Israel, the oldest synagogue in Columbus, Life Church at Easton in NE Columbus and The First Baptist Church of Columbus, Ohio, one of the oldest baptist churches in Columbus, in East Columbus. Megachurches include Xenos Christian Fellowship, Vineyard Columbus, World Harvest


title: "Columbus, Ohio" content: "The Lantern" and "UWeekly" serves The Ohio State University community. "Alternative" arts/culture/politics-oriented papers include Outlook Media's "Outlook: Columbus" (serving the LGBT community in Columbus), and "aLIVE" (formerly the independent "Columbus Alive" and now owned by the "Columbus Dispatch"). The newest addition to the Columbus media scene is "Live Local! Columbus", a free, quarterly magazine that focuses on local arts, culture, and events. The "Columbus Magazine", "CityScene", "(614) Magazine", and "Columbus Monthly" are the city's magazines. Online media publication "ColumbusUnderground.com" also serves the Columbus region as an independently owned alternative voice. The city's business community is served by "The Daily Reporter",


title: Cleveland content: in the city of Cleveland, and again at UFC 211 and UFC 220. The AHL Cleveland Monsters won the 2016 Calder Cup, becoming the first Cleveland pro sports team to do so since the 1964 Cleveland Barons. The city is also host to the Cleveland Gladiators of the Arena Football League, Cleveland Fusion of the Women's Football Alliance and Cleveland SC of the National Premier Soccer League. Collegiately, NCAA Division I Cleveland State Vikings have 16 varsity sports, nationally known for their Cleveland State Vikings men's basketball team. NCAA Division III Case Western Reserve Spartans have 19 varsity sports, most


title: Circe content: told Odysseus to use the herb moly to protect himself from Circe's wizardry and, having resisted it, to draw his sword and act as if he were going to attack her. From there, Circe would ask him to bed, but Hermes advised caution, for even there the goddess would be treacherous. She would take his manhood unless he had her swear by the names of the gods that she would not. Odysseus followed Hermes' advice, freeing his men and then remained on the island for one year, feasting and drinking wine. According to Homer, Circe suggested two alternative routes to


title: "Canadian Pacific Railway" content: to innovate, quickly spun off losing track to short lines, instituted scheduled freight service, and produced an unexpected turn-around in profitability. On 1 January 2001 the StL&H was formally amalgamated with the CP Rail system. In 2001, the CPR's parent company, Canadian Pacific Limited, spun off its five subsidiaries, including the CPR, into independent companies. Most of the company's non-railway businesses at the time of the split were operated by a separate subsidiary called Canadian Pacific Limited. Canadian Pacific Railway formally (but, not legally) shortened its name to Canadian Pacific in early 2007, dropping the word "railway" in order to


title: "Canadian Pacific Railway" content: February 2014, Harrison called for immediate action to phase-out DOT-111 tank cars, known to be more dangerous in cases of derailment. On 12 October 2014 it was reported that Canadian Pacific had tried to enter into a merger with American Railway CSX, but was unsuccessful. In 2015-16 Canadian Pacific sought to merge with American railway Norfolk Southern. and wanted to have a vote on it. Canadian Pacific created a website to persuade people that the Canadian Pacific/Norfolk Southern merger would benefit the rail industry. Canadian Pacific both filed a complaint against the Department of Justice and dropped their proposed proxy


title: Comet content: gases glow from ionisation. Most comets are too faint to be visible without the aid of a telescope, but a few each decade become bright enough to be visible to the naked eye. Occasionally a comet may experience a huge and sudden outburst of gas and dust, during which the size of the coma greatly increases for a period of time. This happened in 2007 to Comet Holmes. In 1996, comets were found to emit X-rays. This greatly surprised astronomers because X-ray emission is usually associated with very high-temperature bodies. The X-rays are generated by the interaction between comets and


title: Capoeira content: they would pay the master any money they made. It is here where capoeira was common as it created opportunities for slaves to practice during and after work. Though tolerated until the 1800's, this quickly became criminalised after due to its association with being African, as well as a threat to the current ruling regime. Soon several groups of escaping slaves would gather and establish quilombos, settlements in far and hard to reach places. Some quilombos would soon increase in size, attracting more fugitive slaves, Brazilian natives and even Europeans escaping the law or Christian extremism. Some quilombos would grow


title: Coal content: Coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed if dead plant matter decays into peat and over millions of years the heat and pressure of deep burial converts the peat into coal. As a fossil fuel burned for heat coal supplies about a quarter of the world’s primary energy and is the largest source of energy for the generation of electricity. Some iron and steel making and other industrial processes burn coal.


title: Coal content: The extraction and use of coal causes many premature deaths and much illness. Coal damages the environment; including by climate change as it is the largest anthropogenic source of carbon dioxide, 14 Gt in 2016 which is 40% of the total fossil fuel emissions. As part of the worldwide energy transition many countries have stopped using or use less coal. The largest consumer and importer of coal is China. And China mines almost half the world's coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports followed by Indonesia and Russia. The


title: Coal content: word originally took the form "col" in Old English, from Proto-Germanic *"kula"("n"), which in turn is hypothesized to come from the Proto-Indo-European root *"g"("e")"u-lo-" "live coal". Germanic cognates include the Old Frisian "kole", Middle Dutch "cole", Dutch "kool", Old High German "chol", German "Kohle" and Old Norse "kol", and the Irish word "gual" is also a cognate via the Indo-European root. Coal is composed of macerals, minerals and water. Fossils and amber may be found in coal. At various times in the geologic past, the Earth had dense forests in low-lying wetland areas. Due to natural processes such as flooding,


title: Coal content: these forests were buried underneath soil. As more and more soil deposited over them, they were compressed. The temperature also rose as they sank deeper and deeper. As the process continued the plant matter was protected from biodegradation and oxidation, usually by mud or acidic water. This trapped the carbon in immense peat bogs that were eventually covered and deeply buried by sediments. Under high pressure and high temperature, dead vegetation was slowly converted to coal. The conversion of dead vegetation into coal is called coalification. Coalification starts with dead plant matter decaying into peat. Then over millions of years


title: Coal content: the heat and pressure of deep burial causes the loss of water, methane and carbon dioxide and an increase in the proportion of carbon. Thus first lignite (also called "brown coal"), then sub-bituminous coal, bituminous coal, and lastly anthracite (also called "hard coal" or "black coal") may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to


title: Coal content: have originated from residues of algae. Sometimes coal seams (also known as coal beds) are interbedded with other sediments in a cyclothem. As geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade or rank increases successively into: Cannel coal (sometimes called "candle coal") is a variety of fine-grained, high-rank coal with significant hydrogen content, which consists primarily of liptinite. There are several international standards for coal. The classification of coal is generally based on the content of volatiles. However the most important distinction is between thermal coal (also known as steam coal), which


title: Coal content: is burnt to generate electricity via steam; and metallurgical coal (also known as coking coal), which is burnt at high temperature to make steel. Hilt's law is a geological observation that (within a small area) the deeper the coal is found, the higher its rank (or grade). It applies if the thermal gradient is entirely vertical; however, metamorphism may cause lateral changes of rank, irrespective of depth. The earliest recognized use is from the Shenyang area of China where by 4000 BC Neolithic inhabitants had begun carving ornaments from black lignite. Coal from the Fushun mine in northeastern China was


title: Coal content: used to smelt copper as early as 1000 BC. Marco Polo, the Italian who traveled to China in the 13th century, described coal as "black stones ... which burn like logs", and said coal was so plentiful, people could take three hot baths a week. In Europe, the earliest reference to the use of coal as fuel is from the geological treatise "On stones" (Lap. 16) by the Greek scientist Theophrastus (c. 371–287 BC): Outcrop coal was used in Britain during the Bronze Age (3000–2000 BC), where it formed part of funeral pyres. In Roman Britain, with the exception of


title: Coal content: two modern fields, "the Romans were exploiting coals in all the major coalfields in England and Wales by the end of the second century AD". Evidence of trade in coal, dated to about AD 200, has been found at the Roman settlement at Heronbridge, near Chester; and in the Fenlands of East Anglia, where coal from the Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and Roman forts, particularly in Northumberland, dated to around AD 400. In the west of England, contemporary writers described the wonder


title: Coal content: of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath), although in fact easily accessible surface coal from what became the Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron-working in the city during the Roman period has been found. In Eschweiler, Rhineland, deposits of bituminous coal were used by the Romans for the smelting of iron ore. No evidence exists of the product being of great importance in Britain before about AD 1000, the High Middle Ages. Mineral coal came to be referred to


title: Coal content: then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process varies between about 25% and 50% depending on the pre-combustion treatment, turbine technology (e.g. supercritical steam generator) and the age of the plant. A few integrated gasification combined cycle (IGCC) power plants have been built, which burn coal more efficiently. Instead of pulverizing the coal and burning it directly as fuel in the steam-generating boiler, the coal is gasified to create syngas, which is burned in a gas turbine to produce electricity (just like natural gas is burned in a turbine). Hot exhaust


title: Coal content: that industrial coal use explains roughly one-third of the urban mortality penalty observed during this period." Coal mining and coal fueling of power stations and industrial processes can cause major environmental damage. Water systems are affected by coal mining. For example, mining affects groundwater and water table levels and acidity. Spills of fly ash, such as the Kingston Fossil Plant coal fly ash slurry spill, can also contaminate land and waterways, and destroy homes. Power stations that burn coal also consume large quantities of water. This can affect the flows of rivers, and has consequential impacts on other land uses.


title: Coal content: India, the Industrial Emissions Directive (EU) and the Clean Air Act (United States). Satellite monitoring is now used to crosscheck national data, for example Sentinel-5 Precursor has shown that Chinese control of SO has only been partially successful. It has also revealed that low use of technology such as SCR has resulted in high NO emissions in South Africa and India. A few Integrated gasification combined cycle (IGCC) coal-fired power plants have been built with coal gasification. Although they burn coal more efficiently and therefore emit less pollution, the technology has not generally proved economically viable for coal, except possibly


title: Coal content: of dollars. The economies most damaged by coal (via climate change) may be India and the US as they are the countries with the highest social cost of carbon. Bank loans to finance coal are a risk to the Indian economy. China is the largest producer of coal in the world. It is the world's largest energy consumer, and coal in China supplies 60% of its primary energy. However two fifths of China's coal power stations are estimated to be loss-making. Air pollution from coal storage and handling costs the USA almost 200 dollars for every extra ton stored, due


title: Climate content: Climate Climate is the statistics of weather over long periods of time. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate differs from weather, in that weather only describes the short-term conditions of these variables in a given region. A region's climate is generated by the climate system, which has five components: atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere. The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water


title: Climate content: bodies and their currents. Climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it. The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region. Paleoclimatology is the study of ancient climates. Since direct observations of climate are not available before


title: Climate content: the 19th century, paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores, and biotic evidence such as tree rings and coral. Climate models are mathematical models of past, present and future climates. Climate change may occur over long and short timescales from a variety of factors; recent warming is discussed in global warming. Global warming results in redistributions. For example, "a 3°C change in mean annual temperature corresponds to a shift in isotherms of approximately 300–400 km in latitude (in the temperate zone) or 500 m in elevation. Therefore,


title: Climate content: species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones". Climate (from Ancient Greek "klima", meaning "inclination") is commonly defined as the weather averaged over a long period. The standard averaging period is 30 years, but other periods may be used depending on the purpose. Climate also includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations. The Intergovernmental Panel on Climate Change (IPCC) 2001 glossary definition is as follows: The World Meteorological Organization (WMO) describes climate "normals" as "reference points used by climatologists to


title: Climate content: compare current climatological trends to that of the past or what is considered 'normal'. A Normal is defined as the arithmetic average of a climate element (e.g. temperature) over a 30-year period. A 30 year period is used, as it is long enough to filter out any interannual variation or anomalies, but also short enough to be able to show longer climatic trends." The WMO originated from the International Meteorological Organization which set up a technical commission for climatology in 1929. At its 1934 Wiesbaden meeting the technical commission designated the thirty-year period from 1901 to 1930 as the reference


title: "Cathode-ray tube" content: poor dynamic convergence. Secondly, each beam must only strike the phosphors of the color it is intended to strike and no others. This is called purity. Like convergence, there is static purity and dynamic purity, with the same meanings of "static" and "dynamic" as for convergence. Convergence and purity are distinct parameters; a CRT could have good purity but poor convergence, or vice versa. Poor convergence causes color "shadows" or "ghosts" along displayed edges and contours, as if the image on the screen were intaglio printed with poor registration. Poor purity causes objects on the screen to appear off-color while


title: "Cathode-ray tube" content: a type of thin CRT known as the "Zeus" display which contained CRT-like functionality in a flat panel display. The devices were demonstrated but never marketed. Some CRT manufacturers, both LG Display and Samsung Display, innovated CRT technology by creating a slimmer tube. Slimmer CRT has a trade name Superslim and Ultraslim. A flat CRT has a depth. The depth of Superslim was and Ultraslim was . Despite being a mainstay of display technology for decades, CRT-based computer monitors and televisions are now virtually a dead technology. Demand for CRT screens dropped precipitously in the last half of the first


title: Crystal content: Crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word "crystal" derives from the Ancient Greek word (), meaning both "ice" and "rock crystal", from (),


title: "Compact space" content: implies the extreme value theorem: a continuous real-valued function on a nonempty compact space is bounded above and attains its supremum. (Slightly more generally, this is true for an upper semicontinuous function.) As a sort of converse to the above statements, the pre-image of a compact space under a proper map is compact. A closed subset of a compact space is compact, and a finite union of compact sets is compact. The product of any collection of compact spaces is compact. (This is Tychonoff's theorem, which is equivalent to the axiom of choice.) Every topological space "X" is an open


title: "Calvin and Hobbes" content: Hobbes plush toy: that if the essence of Hobbes' nature in the strip is that it remain unresolved whether he is a real tiger or a stuffed toy, then creating a real stuffed toy would only destroy the magic. However, having initially signed away control over merchandising in his initial contract with the syndicate, Watterson would commence a lengthy and emotionally draining battle with Universal to gain control over his work. Ultimately Universal did not approve any products against Watterson's wishes, understanding that unlike other comic strips, it would be near impossible to separate the creator from the strip if


title: "Common Lisp" content: Common Lisp Common Lisp (CL) is a dialect of the Lisp programming language, published in ANSI standard document "ANSI INCITS 226-1994 (R2004)" (formerly "X3.226-1994 (R1999)"). The Common Lisp HyperSpec, a hyperlinked HTML version, has been derived from the ANSI Common Lisp standard. The Common Lisp language was developed as a standardized and improved successor of Maclisp. By the early 1980s several groups were already at work on diverse successors to MacLisp: Lisp Machine Lisp (aka ZetaLisp), Spice Lisp, NIL and S-1 Lisp. Common Lisp sought to unify, standardise, and extend the features of these MacLisp dialects. Common Lisp is not


title: "Common Lisp" content: an implementation, but rather a language specification. Several implementations of the Common Lisp standard are available, including free and open-source software and proprietary products. Common Lisp is a general-purpose, multi-paradigm programming language. It supports a combination of procedural, functional, and object-oriented programming paradigms. As a dynamic programming language, it facilitates evolutionary and incremental software development, with iterative compilation into efficient run-time programs. This incremental development is often done interactively without interrupting the running application. It also supports optional type annotation and casting, which can be added as necessary at the later profiling and optimization stages, to permit the compiler to


title: "Common Lisp" content: generate more efficient code. For instance, codice_1 can hold an unboxed integer in a range supported by the hardware and implementation, permitting more efficient arithmetic than on big integers or arbitrary precision types. Similarly, the compiler can be told on a per-module or per-function basis which type safety level is wanted, using "optimize" declarations. Common Lisp includes CLOS, an object system that supports multimethods and method combinations. It is often implemented with a Metaobject Protocol. Common Lisp is extensible through standard features such as "Lisp macros" (code transformations) and "reader macros" (input parsers for characters). Common Lisp provides some backwards


title: "Common Lisp" content: compatibility to Maclisp and to John McCarthy's original Lisp. This allows older Lisp software to be ported to Common Lisp. Work on Common Lisp started in 1981 after an initiative by ARPA manager Bob Engelmore to develop a single community standard Lisp dialect. Much of the initial language design was done via electronic mail. In 1982, Guy L. Steele, Jr. gave the first overview of Common Lisp at the 1982 ACM Symposium on LISP and functional programming. The first language documentation was published 1984 as Common Lisp the Language, first edition. A second edition, published in 1990, incorporated many changes


title: "Common Lisp" content: to the language, made during the ANSI Common Lisp standardization process. The final ANSI Common Lisp standard then was published in 1994. Since then no update to the standard has been published. Various extensions and improvements to Common Lisp (examples are Unicode, Concurrency, CLOS-based IO) have been provided by implementations and libraries (many available via Quicklisp). Common Lisp is a dialect of Lisp. It uses S-expressions to denote both code and data structure. Function calls, macro forms and special forms are written as lists, with the name of the operator first, as in these examples: Common Lisp has many data


title: "Common Lisp" content: types. "Number" types include integers, ratios, floating-point numbers, and complex numbers. Common Lisp uses bignums to represent numerical values of arbitrary size and precision. The ratio type represents fractions exactly, a facility not available in many languages. Common Lisp automatically coerces numeric values among these types as appropriate. The Common Lisp "character" type is not limited to ASCII characters. Most modern implementations allow Unicode characters. The "symbol" type is common to Lisp languages, but largely unknown outside them. A symbol is a unique, named data object with several parts: name, value, function, property list and package. Of these, "value cell"


title: "Common Lisp" content: and "function cell" are the most important. Symbols in Lisp are often used similarly to identifiers in other languages: to hold the value of a variable; however there are many other uses. Normally, when a symbol is evaluated, its value is returned. Some symbols evaluate to themselves, for example all symbols in the keyword package are self-evaluating. Boolean values in Common Lisp are represented by the self-evaluating symbols T and NIL. Common Lisp has namespaces for symbols, called 'packages'. A number of functions are available for rounding scalar numeric values in various ways. The function codice_2 rounds the argument to


title: Canonization content: of a martyr. The bishop of the diocese in which the martyrdom took place set up a canonical process for conducting the inquiry with the utmost severity. The acts of the process were sent either to the metropolitan or primate, who carefully examined the cause, and, after consultation with the suffragan bishops, declared whether the deceased was worthy of the name of 'martyr' and public veneration. Acts of formal recognition, such as the erection of an altar over the saint's tomb or transferring the saint's relics to a church, were preceded by formal inquiries into the sanctity of the person's


title: Canonization content: beatification is needed. For several centuries the Bishops, or in some places only the Primates and Patriarchs, could grant martyrs and confessors public ecclesiastical honor; such honor, however, was always decreed only for the local territory of which the grantors had jurisdiction. Only acceptance of the "cultus" by the Pope made the "cultus" universal, because he alone can rule the universal Catholic Church. Abuses, however, crept into this discipline, due as well to indiscretions of popular fervor as to the negligence of some bishops in inquiring into the lives of those whom they permitted to be honoured as saints. In


title: Chernobyl content: Chernobyl Chernobyl () is a city in the restricted Chernobyl Exclusion Zone situated in the Ivankiv Raion of northern Kiev Oblast, near Ukraine's border with Belarus. Chernobyl is about northeast of Kiev, and approximately southwest of the Belarusian city of Gomel and 16 km [10 mi] from Ukraine’s border with Belarus. The city was the administrative center of Chernobyl Raion (district) from 1923 until it was disestablished in 1988. Before its evacuation, the city had about 14,000 residents. The city was evacuated on 27 April 1986, 30 hours after the Chernobyl disaster at the Chernobyl Nuclear Power Plant which was


title: Cream content: consistency: shoe cream is runny, unlike regular waxy shoe polish; hand/body 'creme' or "skin cream" is meant for moisturizing the skin. Regulations in many jurisdictions restrict the use of the word "cream" for foods. Words such as "creme", "kreme", "creame", or "whipped topping" (e.g., Cool Whip) are often used for products which cannot legally be called cream, though in some jurisdictions even these spellings may be disallowed, for example under the doctrine of "idem sonans". Oreo cookies are a type of sandwich cookie in which two biscuits have a soft, sweet filling between them which is called "crème filling". In


title: "CN Tower" content: felt that visitors would feel the higher observation deck would be worth paying extra for, and the costs in terms of construction were not prohibitive. It was also some time around this point that it was realized that the tower could become the world's tallest structure, and plans were changed to incorporate subtle modifications throughout the structure to this end. Construction on the CN Tower began on February 6, 1973, with massive excavations at the tower base for the foundation. By the time the foundation was complete, of earth and shale were removed to a depth of in the centre,


title: "CN Tower" content: These stairs are intended for emergency use only and are not open to the public, except for twice per year for charity stair-climb events. The average climber takes approximately 30 minutes to climb to the base of the radome, but the fastest climb on record is 7 minutes and 52 seconds in 1989 by Brendan Keenoy, an Ontario Provincial Police officer. In 2002, Canadian Olympian and Paralympic champion Jeff Adams climbed the stairs of the tower in a specially designed wheelchair. The stairs were originally on one of the three sides of the tower (facing north), with a glass view,


title: "CN Tower" content: The CN Tower is the tallest freestanding structure in the Western Hemisphere. As of 2013, there are only two other freestanding structures in the Western Hemisphere which exceed in height; the Willis Tower in Chicago, which stands at when measured to its pinnacle; and the topped-out One World Trade Center in New York City, which has a pinnacle height of , or approximately shorter than the CN Tower. Due to the symbolism of the number 1776 (the year of the signing of the United States Declaration of Independence), the height of One World Trade Center is unlikely to be increased.


title: "CN Tower" content: thus partially supported by its buoyancy. Like the CN Tower, none of these taller structures are commonly considered buildings. On September 12, 2007, Burj Khalifa, which is a hotel, residential and commercial building in Dubai, United Arab Emirates, and was formerly known as Burj Dubai before opening, passed the CN Tower's 553.33-metre height. The CN Tower held the record of tallest free-standing structure on land for over 30 years. After Burj Khalifa had been formally recognized by the Guinness World Records as the world's tallest freestanding structure, Guinness re-certified CN Tower as the world's tallest freestanding tower. The tower definition


title: "P versus NP problem" content: "semi-algorithm"). This algorithm is enormously impractical, even if P = NP. If the shortest program that can solve SUBSET-SUM in polynomial time is "b" bits long, the above algorithm will try at least other programs first. Conceptually speaking, a "decision problem" is a problem that takes as input some string "w" over an alphabet Σ, and outputs "yes" or "no". If there is an algorithm (say a Turing machine, or a computer program with unbounded memory) that can produce the correct answer for any input string of length "n" in at most "cn" steps, where "k" and "c" are constants


title: "Central America" content: Central America Central America (, , "Centroamérica" ) is located on the southern tip of North America, or is sometimes defined as a subcontinent of the Americas , bordered by Mexico to the north, Colombia to the southeast, the Caribbean Sea to the east, and the Pacific Ocean to the west and south. Central America consists of seven countries: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. The combined population of Central America has been estimated to be 41,739,000 (2009 estimate) and 42,688,190 (2012 estimate). Central America is a part of the Mesoamerican biodiversity hotspot, which extends from


title: "Central America" content: northern Guatemala through to central Panama. Due to the presence of several active geologic faults and the Central America Volcanic Arc, there is a great deal of seismic activity in the region. Volcanic eruptions and earthquakes occur frequently; these natural disasters have resulted in the loss of many lives and much property. In the Pre-Columbian era, Central America was inhabited by the indigenous peoples of Mesoamerica to the north and west and the Isthmo-Colombian peoples to the south and east. Soon after Italian explorer Christopher Columbus's voyages to the Americas, the Spanish began to colonize the Americas. From 1609 until


title: "Central America" content: 1821, most of the territory within Central America—except for the lands that would become Belize and Panama—was governed by the Viceroyalty of New Spain from Mexico City as the Captaincy General of Guatemala. After New Spain achieved independence from Spain in 1821, some of its provinces were annexed to the First Mexican Empire, but soon seceded from Mexico to form the Federal Republic of Central America, which lasted from 1823 to 1838. The seven states finally became independent autonomous states: beginning with Nicaragua, Honduras, Costa Rica, and Guatemala (1838); followed by El Salvador (1841); then Panama (1903); and finally Belize


title: "Central America" content: (1981). Even today, people in Central America sometimes refer to their nations as if they were provinces of a Central American state. For example, it is not unusual to write "C.A." after the country names in formal and informal contexts and the automobile licence plates of many of the countries in the region show the legend "Centroamerica" in addition to the country name. "Central America" may mean different things to various people, based upon different contexts: In the Pre-Columbian era, the northern areas of Central America were inhabited by the indigenous peoples of Mesoamerica. Most notable among these were the


title: "Central America" content: Mayans, who had built numerous cities throughout the region, and the Aztecs, who had created a vast empire. The pre-Columbian cultures of eastern El Salvador, eastern Honduras, Caribbean Nicaragua, most of Costa Rica and Panama were predominantly speakers of the Chibchan languages at the time of European contact and are considered by some culturally different and grouped in the Isthmo-Colombian Area. Following Christopher Columbus's voyages to the Americas, the Spanish sent many expeditions to the region, and they began their conquest of Maya territory in 1523. Soon after the conquest of the Aztec Empire, Spanish conquistador Pedro de Alvarado commenced


title: "Central America" content: the conquest of northern Central America for the Spanish Empire. Beginning with his arrival in Soconusco in 1523, Alvarado's forces systematically conquered and subjugated most of the major Maya kingdoms, including the K'iche', Tz'utujil, Pipil, and the Kaqchikel. By 1528, the conquest of Guatemala was nearly complete, with only the Petén Basin remaining outside the Spanish sphere of influence. The last independent Maya kingdoms – the Kowoj and the Itza people – were finally defeated in 1697, as part of the Spanish conquest of Petén. In 1538, Spain established the Real Audiencia of Panama, which had jurisdiction over all land


title: "Central America" content: from the Strait of Magellan to the Gulf of Fonseca. This entity was dissolved in 1543, and most of the territory within Central America then fell under the jurisdiction of the "Audiencia Real de Guatemala". This area included the current territories of Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and the Mexican state of Chiapas, but excluded the lands that would become Belize and Panama. The president of the Audiencia, which had its seat in Antigua Guatemala, was the governor of the entire area. In 1609 the area became a captaincy general and the governor was also granted the title


title: "Central America" content: of captain general. The Captaincy General of Guatemala encompassed most of Central America, with the exception of present-day Belize and Panama. The Captaincy General of Guatemala lasted for more than two centuries, but began to fray after a rebellion in 1811 which began in the intendancy of San Salvador. The Captaincy General formally ended on 15 September 1821, with the signing of the Act of Independence of Central America. Mexican independence was achieved at virtually the same time with the signing of the Treaty of Córdoba and the Declaration of Independence of the Mexican Empire, and the entire region was


title: "Central America" content: finally independent from Spanish authority by 28 September 1821. From its independence from Spain in 1821 until 1823, the former Captaincy General remained intact as part of the short-lived First Mexican Empire. When the Emperor of Mexico abdicated on 19 March 1823, Central America again became independent. On 1 July 1823, the Congress of Central America peacefully seceded from Mexico and declared absolute independence from all foreign nations, and the region formed the Federal Republic of Central America. The Federal Republic of Central America was a representative democracy with its capital at Guatemala City. This union consisted of the provinces


title: "Central America" content: of Costa Rica, El Salvador, Guatemala, Honduras, Los Altos, Mosquito Coast, and Nicaragua. The lowlands of southwest Chiapas, including Soconusco, initially belonged to the Republic until 1824, when Mexico annexed most of Chiapas and began its claims to Soconusco. The Republic lasted from 1823 to 1838, when it disintegrated as a result of civil wars. The territory that now makes up Belize was heavily contested in a dispute that continued for decades after Guatemala achieved independence (see History of Belize (1506–1862). Spain, and later Guatemala, considered this land a Guatemalan department. In 1862, Britain formally declared it a British colony


title: "Carbon monoxide" content: thus, utilize carbon monoxide in such locations as the thermal vents of volcanoes. Some microbes can convert carbon monoxide to carbon dioxide to yield energy. In bacteria, carbon monoxide is produced via the reduction of carbon dioxide by the enzyme carbon monoxide dehydrogenase, an Fe-Ni-S-containing protein. CooA is a carbon monoxide sensor protein. The scope of its biological role is still unknown; it may be part of a signaling pathway in bacteria and archaea. Its occurrence in mammals is not established. Carbon monoxide occurs in various natural and artificial environments. Typical concentrations in parts per million are as follows: Carbon


title: "Carbon monoxide" content: is produced by passing purified carbon monoxide and chlorine gas through a bed of porous activated carbon, which serves as a catalyst. World production of this compound was estimated to be 2.74 million tonnes in 1989. Methanol is produced by the hydrogenation of carbon monoxide. In a related reaction, the hydrogenation of carbon monoxide is coupled to C-C bond formation, as in the Fischer-Tropsch process where carbon monoxide is hydrogenated to liquid hydrocarbon fuels. This technology allows coal or biomass to be converted to diesel. In the Monsanto process, carbon monoxide and methanol react in the presence of a homogeneous


title: "Carbon monoxide" content: monoxide is not usually supplied as is, in gaseous phase, in the reactor, but rather it is formed in high temperature in presence of oxygen-carrying ore, carboniferous agent such as coke and high temperature. The blast furnace process is a typical example of a process of reduction of metal from ore with carbon monoxide. Carbon monoxide has also been used as a lasing medium in high-powered infrared lasers. Carbon monoxide has been proposed for use as a fuel on Mars. Carbon monoxide/oxygen engines have been suggested for early surface transportation use as both carbon monoxide and oxygen can be straightforwardly


title: Claudius content: also presided over many new and original events. Soon after coming into power, Claudius instituted games to be held in honor of his father on the latter's birthday. Annual games were also held in honour of his accession, and took place at the Praetorian camp where Claudius had first been proclaimed Emperor. Claudius organised a performance of the Secular Games, marking the 800th anniversary of the founding of Rome. Augustus had performed the same games less than a century prior. Augustus' excuse was that the interval for the games was 110 years, not 100, but his date actually did not


title: Claudius content: descended from Octavia and Antony on one side – not close enough to the Imperial family to prevent doubts (although that did not stop others from making him the object of a coup attempt against Nero a few years later). Besides which, he was the half-brother of Valeria Messalina and at this time those wounds were still fresh. Nero was more popular with the general public as the grandson of Germanicus and the direct descendant of Augustus. The historian Suetonius describes the physical manifestations of Claudius' affliction in relatively good detail. His knees were weak and gave way under him


title: Cardinality content: Grand Hotel). The second result was first demonstrated by Cantor in 1878, but it became more apparent in 1890, when Giuseppe Peano introduced the space-filling curves, curved lines that twist and turn enough to fill the whole of any square, or cube, or hypercube, or finite-dimensional space. These curves are not a direct proof that a line has the same number of points as a finite-dimensional space, but they can be used to obtain such a proof. Cantor also showed that sets with cardinality strictly greater than formula_15 exist (see his generalized diagonal argument and theorem). They include, for instance:


title: "Cantonese cuisine" content: soup broth or fried. These are available as home-cooked meals, on dim sum side menus, or as street food at dai pai dongs, where they can be served with a variety of toppings such as fish balls, beef balls, or fish slices. "Siu mei" () is essentially the Chinese rotisserie style of cooking. Unlike most other Cantonese dishes, "siu mei" solely consists of meat, with no vegetables. Lou mei () is the name given to dishes made from internal organs, entrails and other left-over parts of animals. It is widely available in southern Chinese regions. All Cantonese-style cooked meats, including


title: "Buddhist cuisine" content: as full-time vegetarians, the menu of a Buddhist vegetarian restaurant usually shows no difference from a typical Chinese or East Asian restaurant, except that in recipes originally made to contain meat, a soy chicken substitute might be served instead. According to cookbooks published in English, formal monastery meals in the Zen tradition generally follow a pattern of "three bowls" in descending size. The first and largest bowl is a grain-based dish such as rice, noodles or congee; the second contains the protein dish which is often some form of stew or soup; the third and smallest bowl is a vegetable


title: "Electric current" content: Electric current An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas (plasma). The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter. Electric currents cause Joule heating, which creates light in incandescent light bulbs. They


title: "Electric current" content: also create magnetic fields, which are used in motors, inductors and generators. The moving charged particles in an electric current are called charge carriers. In metals, one or more electrons from each atom are loosely bound to the atom, and can move freely about within the metal. These conduction electrons are the charge carriers in metal conductors. The conventional symbol for current is , which originates from the French phrase "intensité du courant", (current intensity). Current intensity is often referred to simply as "current". The symbol was used by André-Marie Ampère, after whom the unit of electric current is named,


title: "Electric current" content: in formulating Ampère's force law (1820). The notation travelled from France to Great Britain, where it became standard, although at least one journal did not change from using to until 1896. In a conductive material, the moving charged particles that constitute the electric current are called charge carriers. In metals, which make up the wires and other conductors in most electrical circuits, the positively charged atomic nuclei of the atoms are held in a fixed position, and the negatively charged electrons are the charge carriers, free to move about in the metal. In other materials, notably the semiconductors, the charge


title: "Electric current" content: carriers can be positive "or" negative, depending on the dopant used. Positive and negative charge carriers may even be present at the same time, as happens in an electrolyte in an electrochemical cell. A flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction. Since current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of current that is independent of the type of charge carriers. The direction of "conventional current" is


title: "Electric current" content: arbitrarily defined as the same direction as positive charges flow. Since electrons, the charge carriers in metal wires and most other parts of electric circuits, have a negative charge, as a consequence, they flow in the opposite direction of conventional current flow in an electrical circuit. Since the current in a wire or component can flow in either direction, when a variable is defined to represent that current, the direction representing positive current must be specified, usually by an arrow on the circuit schematic diagram. This is called the "reference direction" of current . If the current flows in the


title: "Electric current" content: opposite direction, the variable has a negative value. When analyzing electrical circuits, the actual direction of current through a specific circuit element is usually unknown. Consequently, the reference directions of currents are often assigned arbitrarily. When the circuit is solved, a negative value for the variable means that the actual direction of current through that circuit element is opposite that of the chosen reference direction. In electronic circuits, the reference current directions are often chosen so that all currents are toward ground. This often corresponds to the actual current direction, because in many circuits the power supply voltage is positive


title: "Electric current" content: with respect to ground. Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship: where "I" is the current through the conductor in units of amperes, "V" is the potential difference measured "across" the conductor in units of volts, and "R" is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the "R" in this relation is constant, independent of the current. In


title: "Electric current" content: alternating current (AC) systems, the movement of electric charge periodically reverses direction. AC is the form of electric power most commonly delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. Certain applications use different waveforms, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. An important goal in these applications is recovery of information encoded (or "modulated") onto the AC signal. In contrast, direct current (DC) is the unidirectional flow of electric charge, or a system in which the movement of


title: "Electric current" content: electric charge is in one direction only. Direct current is produced by sources such as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. An old name for direct current was "galvanic current". Natural observable examples of electrical current include lightning, static electric discharge, and the solar wind, the source of the polar auroras. Man-made occurrences of electric current include the flow of conduction electrons in metal wires


title: "Electric current" content: such as the overhead power lines that deliver electrical energy across long distances and the smaller wires within electrical and electronic equipment. Eddy currents are electric currents that occur in conductors exposed to changing magnetic fields. Similarly, electric currents occur, particularly in the surface, of conductors exposed to electromagnetic waves. When oscillating electric currents flow at the correct voltages within radio antennas, radio waves are generated. In electronics, other forms of electric current include the flow of electrons through resistors or through the vacuum in a vacuum tube, the flow of ions inside a battery or a neuron, and the


title: Circle content: Circle A circle is a simple closed shape. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius. This article is about circles in Euclidean geometry, and, in particular, the Euclidean plane, except where otherwise noted. A circle is a simple closed curve that divides the plane into two regions: an interior


title: Circle content: and an exterior. In everyday use, the term "circle" may be used interchangeably to refer to either the boundary of the figure, or to the whole figure including its interior; in strict technical usage, the circle is only the boundary and the whole figure is called a disc. A circle may also be defined as a special kind of ellipse in which the two foci are coincident and the eccentricity is 0, or the two-dimensional shape enclosing the most area per unit perimeter squared, using calculus of variations. The word "circle" derives from the Greek κίρκος/κύκλος ("kirkos/kuklos"), itself a metathesis


title: Circle content: of the Homeric Greek κρίκος ("krikos"), meaning "hoop" or "ring". The origins of the words "circus" and "circuit" are closely related. The circle has been known since before the beginning of recorded history. Natural circles would have been observed, such as the Moon, Sun, and a short plant stalk blowing in the wind on sand, which forms a circle shape in the sand. The circle is the basis for the wheel, which, with related inventions such as gears, makes much of modern machinery possible. In mathematics, the study of the circle has helped inspire the development of geometry, astronomy and