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In physics, radiation describes a process in which energetic particles or waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing. The word radiation is commonly used in reference to ionizing radiation only (i.e., having sufficient energy to ionize an atom), but it may also refer to non-ionizing radiation (e.g., radio waves or visible light). The energy radiates (i.e., travels outward in straight lines in all directions) from its source. This geometry naturally leads to a system of measurements and physical units that are equally applicable to all types of radiation. Both ionizing and non-ionizing radiation can be harmful to organisms and can result in changes to the natural environment.
Alpha particles, beta particles, gamma rays, X-ray radiation, and neutrons may all be accelerated to a high enough energy to ionize atoms.
An alpha (α) particle is commonly emitted during the decay of large nuclei. An alpha particle (identical to a helium nucleus, He2+) consists of two neutrons and two protons. This particle has a doubly positive charge and a relatively high atomic mass. It travels relatively slowly and is stopped quickly through ionizing interactions with other atoms. To a human being, material emitting alpha radiation presents little to no external hazard, since it is unable to penetrate the dead skin layer. However, if ingested, alpha-emitting radioactive material can cause internal ionization. This can lead to cell damage, cell death or the development of cancer. Alpha particles can be stopped with a sheet of paper.
Beta-plus (β+) radiation is the emission of positrons. Because these are antimatter particles, they annihilate any matter nearby, releasing gamma photons.
Gamma rays, which are highly energetic photons, penetrate deeply and are difficult to stop. They can be stopped by a sufficiently thick layer of material with high atomic number, such as lead or depleted uranium.
High-energy neutrons can travel great distances in air and typically require hydrogen rich shielding, such as concrete or water, to block them. A common source of neutron radiation occurs inside a nuclear reactor, where many feet of water is used as effective shielding.
The energy of non-ionizing radiation is less and instead of producing charged ions when passing through matter, the electromagnetic radiation has only sufficient energy to change the rotational, vibrational or electronic valence configurations of molecules and atoms. The effect of non-ionizing forms of radiation on living tissue have only recently been studied. Nevertheless, different biological effects are observed for different types of non-ionizing radiation.
Neutron radiation is a kind of non-ionizing radiation that consists of free neutrons. These neutrons may be emitted during either spontaneous or induced nuclear fission, nuclear fusion processes, or from any other nuclear reactions. It does not ionize atoms in the same way that charged particles such as protons and electrons do (exciting an electron), because neutrons have no charge. However, neutrons react with the atomic nuclei of many elements upon collision with nuclei, creating unstable isotopes and therefore inducing radioactivity in a previously non-radioactive material. This process is known as neutron activation.
Electromagnetic radiation (sometimes abbreviated EMR) takes the form of self-propagating waves in a vacuum or in matter. EM radiation has an electric and magnetic field component which oscillate in phase perpendicular to each other and to the direction of energy propagation. Electromagnetic radiation is classified into types according to the frequency of the wave, these types include (in order of increasing frequency): radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. Of these, radio waves have the longest wavelengths and gamma rays have the shortest. A small window of frequencies, called visible spectrum or light, is sensed by the eye of various organisms.
Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them. The occurrence of ionization depends on the energy of the individual particles or waves, and not on their number. An intense flood of particles or waves will not cause ionization if these particles or waves do not carry enough energy to be ionizing. Roughly speaking, particles or photons with energies above a few electron volts (eV) are ionizing.
Examples of ionizing particles are energetic alpha particles, beta particles, and neutrons. The ability of an electromagnetic wave (photons) to ionize an atom or molecule depends on its frequency. Radiation on the short-wavelength end of the electromagnetic spectrum—high frequency ultraviolet, X-rays, and gamma rays—is ionizing.
Ionizing radiation comes from radioactive materials, X-ray tubes, particle accelerators, and is present in the environment. It is invisible and not directly detectable by human senses, so instruments such as Geiger counters are usually required to detect its presence. In some cases, it may lead to secondary emission of visible light upon interaction with matter, as in Cherenkov radiation and radioluminescence. It has many practical uses in medicine, research, construction, and other areas, but presents a health hazard if used improperly. Exposure to radiation causes damage to living tissue, resulting in skin burns, radiation sickness and death at high doses and cancer,
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
Name | The Times |
---|---|
Caption | The 25 August 2010 front page of The Times |
Type | Daily newspaper |
Format | Compact (Monday–Saturday)broadsheet (Sunday) |
Price | UK£0.90 (Monday–Friday)£2 (Saturday) £1.30(Sat., Scotland) |
Foundation | 1 January 1785 |
Owners | News Corporation |
Political | Moderate Conservative |
Headquarters | Wapping, London, UK |
Editor | James Harding |
Issn | 0140-0460 |
Website | www.thetimes.co.uk |
Circulation | 502,436 March 2010 |
The Times and its sister paper The Sunday Times are published by Times Newspapers Limited, a subsidiary of News International. News International is entirely owned by the News Corporation group, headed by Rupert Murdoch. Though traditionally a moderately centre-right newspaper and a supporter of the Conservatives, it supported the Labour Party in the 2001 and 2005 general elections. In 2005, according to MORI, the voting intentions of its readership were 40% for the Conservative Party, 29% for the Liberal Democrats, 26% for Labour.
The Times is the original "Times" newspaper, lending its name to many other papers around the world, such as The New York Times, The Los Angeles Times, The Daily Times (Malawi), The Times of India, The Straits Times, The Times of Malta and The Irish Times. For distinguishing purposes it is therefore sometimes referred to, particularly in North America, as the 'London Times' or 'The Times of London'. The paper is the originator of the ubiquitous Times Roman typeface, originally developed by Stanley Morison of The Times in collaboration with the Monotype Corporation for its legibility in low-tech printing.
The Times was printed in broadsheet format for 219 years, but switched to tabloid size in 2004 partly in an attempt to appeal to younger readers and partly to appeal to commuters using public transport. An American edition has been published since 6 June 2006.
The Times used contributions from significant figures in the fields of politics, science, literature, and the arts to build its reputation. For much of its early life, the profits of The Times were very large and the competition minimal, so it could pay far better than its rivals for information or writers.
In 1809, John Stoddart was appointed general editor, replaced in 1817 with Thomas Barnes. Under Barnes and his successor in 1841, John Thadeus Delane, the influence of The Times rose to great heights, especially in politics and amongst the City of London. Peter Fraser and Edward Sterling were two noted journalists, and gained for The Times the pompous/satirical nickname 'The Thunderer' (from "We thundered out the other day an article on social and political reform.").The increased circulation and influence of the paper was based in part to its early adoption of the steam driven rotary printing press. Distribution via steam trains to rapidly growing concentrations of urban populations helped ensure the profitability of the paper and its growing influence.
The Times was the first newspaper to send war correspondents to cover particular conflicts. W. H. Russell, the paper's correspondent with the army in the Crimean War, was immensely influential with his dispatches back to England. , in John Everett Millais' painting Peace Concluded.]] In other events of the nineteenth century, The Times opposed the repeal of the Corn Laws until the number of demonstrations convinced the editorial board otherwise, and only reluctantly supported aid to victims of the Irish Potato Famine. It enthusiastically supported the Great Reform Bill of 1832 which reduced corruption and increased the electorate from 400 000 people to 800 000 people (still a small minority of the population). During the American Civil War, The Times represented the view of the wealthy classes, favouring the secessionists, but it was not a supporter of slavery.
The third John Walter (the founder's grandson) succeeded his father in 1847. The paper continued as more or less independent. From the 1850s, however, The Times was beginning to suffer from the rise in competition from the penny press, notably The Daily Telegraph and The Morning Post.
During the 19th century, it was not infrequent for the Foreign Office to approach The Times and ask for continental intelligence, which was often superior to that conveyed by official sources.
The Times faced financial extinction in 1890 under Arthur Fraser Walter, but it was rescued by an energetic editor, Charles Frederic Moberly Bell. During his tenure (1890–1911), The Times became associated with selling the Encyclopædia Britannica using aggressive American marketing methods introduced by Horace Everett Hooper and his advertising executive, Henry Haxton. However, due to legal fights between the Britannica's two owners, Hooper and Walter Montgomery Jackson, The Times severed its connection in 1908 and was bought by pioneering newspaper magnate, Alfred Harmsworth, later Lord Northcliffe.
In editorials published on 29 and 31 July 1914 Wickham Steed, the Times's Chief Editor argued that the British Empire should enter World War I. On 8 May 1920, under the editorship of Wickham Steed, the Times in an editorial endorsed the anti-Semitic forgery The Protocols of the Learned Elders of Zion as a genuine document, and called Jews the world’s greatest danger. In the leader entitled "The Jewish Peril, a Disturbing Pamphlet: Call for Inquiry", Steed wrote about the The Protocols of the Elders of Zion:
What are these 'Protocols'? Are they authentic? If so, what malevolent assembly concocted these plans and gloated over their exposition? Are they forgery? If so, whence comes the uncanny note of prophecy, prophecy in part fulfilled, in part so far gone in the way of fulfillment?".The following year, when Philip Graves, the Constantinople (modern Istanbul, Turkey) correspondent of the Times exposed The Protocols as a forgery, the Times retracted the editorial of the previous year.
In 1922, John Jacob Astor, a son of the 1st Viscount Astor, bought The Times from the Northcliffe estate. The paper gained a measure of notoriety in the 1930s with its advocacy of German appeasement; then-editor Geoffrey Dawson was closely allied with those in the government who practised appeasement, most notably Neville Chamberlain.
Kim Philby, a Soviet double agent, served as a correspondent for the newspaper in Spain during the Spanish Civil War of the late 1930s. Philby was admired for his courage in obtaining high-quality reporting from the front lines of the bloody conflict. He later joined MI6 during World War II, was promoted into senior positions after the war ended, then eventually defected to the Soviet Union in 1963.
Between 1941-1946, the left-wing British historian E. H. Carr served as Assistant Editor. Carr was well-known for the strongly pro-Soviet tone of his editorials. In December 1944, when fighting broke out in Athens between the Greek Communist ELAS and the British Army, Carr in a Times editorial sided with the Communists, leading Winston Churchill to condemn him and that leader in a speech to the House of Commons. As a result of Carr’s editorial, the Times became popularly known during World War II as the threepenny Daily Worker (the price of the Daily Worker was one penny)
In 1967, members of the Astor family sold the paper to Canadian publishing magnate Roy Thomson, and on 3 May 1966 it started printing news on the front page for the first time. (Previously, the paper's front page featured small advertisements, usually of interest to the moneyed classes in British society.) The Thomson Corporation merged it with The Sunday Times to form Times Newspapers Limited.
An industrial dispute prompted the management to shut the paper for nearly a year (1 December 1978–12 November 1979).
The Thomson Corporation management were struggling to run the business due to the 1979 Energy Crisis and union demands. Management were left with no choice but to save both titles by finding a buyer who was in a position to guarantee the survival of both titles, and also one who had the resources and was committed to funding the introduction of modern printing methods.
Several suitors appeared, including Robert Maxwell, Tiny Rowland and Lord Rothermere; however, only one buyer was in a position to fulfil the full Thomson remit. That buyer was the Australian media baron Rupert Murdoch.
Murdoch soon began making his mark on the paper, replacing its editor, William Rees-Mogg, with Harold Evans in 1981. One of his most important changes was in the introduction of new technology and efficiency measures. In March–May 1982, following agreement with print unions, the hot-metal Linotype printing process used to print The Times since the 19th century was phased out and replaced by computer input and photo-composition. This allowed the staff of the print rooms of The Times and The Sunday Times to be reduced by half. However, direct input of text by journalists ("single stroke" input) was still not achieved, and this was to remain an interim measure until the Wapping dispute of 1986, which saw The Times move from its home at New Printing House Square in Gray's Inn Road (near Fleet Street) to new offices in Wapping.
In June 1990, The Times ceased its policy of using courtesy titles ("Mr", "Mrs", or "Miss" prefixes for living persons) before full names on first reference, but it continues to use them before surnames on subsequent references. The more formal style is now confined to the "Court and Social" page, though "Ms" is now acceptable in that section, as well as before surnames in news sections.
In November 2003, News International began producing the newspaper in both broadsheet and tabloid sizes. On 13 September 2004, the weekday broadsheet was withdrawn from sale in Northern Ireland. Since 1 November 2004, the paper has been printed solely in tabloid format.
The Conservative Party announced plans to launch litigation against The Times over an incident in which the newspaper claimed that Conservative election strategist Lynton Crosby had admitted that his party would not win the 2005 General Election. The Times later published a clarification, and the litigation was dropped.
On 6 June 2005, The Times redesigned its Letters page, dropping the practice of printing correspondents' full postal addresses. Published letters were long regarded as one of the paper's key constituents. Author/solicitor David Green of Castle Morris Pembrokeshire has had more letters published on the main letters page than any known contributor - 158 by 31 January 2008. According to its leading article, "From Our Own Correspondents", removal of full postal addresses was in order to fit more letters onto the page.
In a 2007 meeting with the House of Lords Select Committee on Communications who were investigating media ownership and the news, Murdoch stated that the law and the independent board prevented him from exercising editorial control.
In May 2008 printing of The Times switched from Wapping to new plants at Broxbourne, on the outskirts of London, Merseyside and Glasgow, enabling the paper to be produced with full colour on every page for the first time.
Some allege that The Times' partisan opinion pieces also damage its status as 'paper of record,' particularly when attacking interests that go against those of its parent company - News International. It recently published an opinion piece attacking the BBC for being 'one of a group of' signatories to a letter criticising BSkyB share options in October 2010
The latest figures from the national readership survey show The Times to have the highest number of ABC1 25–44 readers and the largest numbers of readers in London of any of the "quality" papers. The certified average circulation figures for November 2005 show that The Times sold 692,581 copies per day. This was the highest achieved under the last editor, Robert Thomson, and ensured that the newspaper remained ahead of The Daily Telegraph in terms of full rate sales, although the Telegraph remains the market leader for broadsheets, with a circulation of 905,955 copies. Tabloid newspapers, such as The Sun and middle-market newspapers such as the Daily Mail, at present outsell both papers with a circulation of around 3,005,308 and 2,082,352 respectively.[6] By March 2010 the paper's circulation had fallen to 502,436 copies daily and the Telegraph's to 686,679, according to ABC figures.
The Times started another new (but free) monthly science magazine, Eureka, in October 2009.
The supplement also contained arts and lifestyle features, TV and radio listings and reviews which have now become their own weekly supplements.
Saturday Review is the first regular supplement published in broadsheet format again since the paper switched to a compact size in 2004.
The Times Magazine features columns touching on various subjects such as celebrities, fashion and beauty, food and drink, homes and gardens or simply writers' anecdotes. Notable contributors include Giles Coren, Food And Drink Writer of the Year in 2005.
There are now two websites, instead of one: thetimes.co.uk is aimed at daily readers, and the thesundaytimes.co.uk site at providing weekly magazine-like content.
According to figures released in November 2010 by The Times, 100,000 people had paid to use the service in its first four months of operation, as well as another 100,000 people who receive free access due to subscribing to the printed version of the newspaper. Visits to the websites have decreased by 87% since the paywall was introduced, from 21 million unique users per month to 2.7 million.
In November 2010, The Times partnered with 3G mobile network Three mobile to offer its broadband customers free access to its paywalled sites thetimes.co.uk and thesundaytimes.co.uk for three months.
The Times also sponsors the Cheltenham Literature Festival and the Asia House Festival of Asian Literature at Asia House, London.
Category:Newspapers published in the United Kingdom Category:News Corporation subsidiaries Category:The Times Category:Publications established in 1785
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.