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Marine Reservoir Effect
The marine reservoir effect is a phenomenon affecting radiocarbon dating. Because much of the carbon consumed by organisms in the ocean is older than that consumed by organisms on land, samples from marine life and from organisms that consumed a lot of sea-based foods while alive may appear older when tested than they truly are. It is necessary to account for changes in the Earth's oceans to correct for the marine reservoir effect. The level of the effect on a particular sample varies significantly, depending on the body of water, and more locally on depths, upwelling currents, and freshwater discharges. Typically, affected radiocarbon dates appear c. 400 14C years older than they would if unaffected. But the effect is highly variable in space and time, and can reach 800 to 1200 14C years in Arctic regions. In 2013, archaeologists at the Gottorp Castle Museum tested the effects of fish prepared in a newly made clay vessel on their ability to accurately measure carbon-14 in the cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotopes of carbon, isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Atmosphere of Earth, Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Carbon-14
Carbon-14, C-14, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934. There are three naturally occurring isotopes of carbon on Earth: carbon-12 (C), which makes up 99% of all carbon on Earth; carbon-13 (C), which makes up 1%; and carbon-14 (C), which occurs in trace amounts, making up about 1-1.5 atoms per 10 atoms of carbon in the atmosphere. C and C are both stable; C is unstable, with half-life years. Carbon-14 has a specific activity of 62.4 mCi/mmol (2.31 GBq/mmol), or 164.9 GBq/g. Carbon-14 decay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Vikings
Vikings were seafaring people originally from Scandinavia (present-day Denmark, Norway, and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe.Roesdahl, pp. 9–22. They also voyaged as far as the Mediterranean Sea, Mediterranean, North Africa, the Middle East, Greenland, and Vinland (present-day Newfoundland in Canada, North America). In their countries of origin, and some of the countries they raided and settled in, this period is popularly known as the Viking Age, and the term "Viking" also commonly includes the inhabitants of the Scandinavian homelands as a whole. The Vikings had a profound impact on the Early Middle Ages, early medieval history of Northern Europe, northern and Eastern Europe, including the political and social development of England (and the English language) and parts of France, and established the embryo of Russia in Kievan Rus'. Expert sailors and navigators of their cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Great Heathen Army
The Great Heathen Army, also known as the Viking Great Army,Hadley. "The Winter Camp of the Viking Great Army, AD 872–3, Torksey, Lincolnshire", ''Antiquaries Journal''. 96, pp. 23–67 was a coalition of Scandinavian warriors who invaded England in 865 AD. Since the late 8th century, the Vikings had been engaging in raids on centres of wealth, such as monasteries. The Great Heathen Army was much larger and aimed to conquer and occupy the four kingdoms of East Anglia, Northumbria, Mercia and Wessex. The name ''Great Heathen Army'' is derived from the '' Anglo-Saxon Chronicle''. The force was led by three of the five sons of the semi-legendary Ragnar Lodbrok, including Halfdan Ragnarsson, Ivar the Boneless and Ubba. The campaign of invasion and conquest against the Anglo-Saxon kingdoms lasted 14 years. Surviving sources give no firm indication of its numbers, but it was described as amongst the largest forces of its kind. The invaders initially landed in East Ang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
University Of Bristol
The University of Bristol is a public university, public research university in Bristol, England. It received its royal charter in 1909, although it can trace its roots to a Merchant Venturers' school founded in 1595 and University College, Bristol, which had been in existence since 1876. Bristol Medical School, founded in 1833, was merged with the University College in 1893, and later became the university's school of medicine. The university is organised into #Academic structure, six academic faculties composed of multiple schools and departments running over 200 undergraduate courses, largely in the Tyndalls Park area of the city. It had a total income of £1.06 billion in 2023–24, of which £294.1 million was from research grants and contracts, with an expenditure of £768.7 million. It is the largest independent employer in Bristol. Current academics include 23 fellows of the Academy of Medical Sciences, 13 fellows of the British Academy, 43 fellows of the Academy of Soc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotopes of carbon, isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Atmosphere of Earth, Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
American Inventions ...
The following articles cover the timeline of United States inventions: * Timeline of United States of America inventions (before 1890), before the turn of the century * Timeline of United States inventions (1890–1945), before World War II * Timeline of United States inventions (1946–1991), during the Cold War * Timeline of United States inventions (after 1991), after the dissolution of the Soviet Union {{DEFAULTSORT:Timeline of United States Inventions United States inventions United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Conservation And Restoration Of Cultural Heritage
conservation and restoration of cultural property focuses on protection and care of cultural property (tangible cultural heritage), including artworks, architecture, archaeology, and museum collections. Conservation activities include preventive conservation, examination, documentation, research, treatment, and education. This field is closely allied with conservation science, curators and registrars. Definition Conservation of cultural property involves protection and restoration using "any methods that prove effective in keeping that property in as close to its original condition as possible for as long as possible." Conservation of cultural heritage is often associated with art collections and museums and involves collection care and management through tracking, examination, documentation, exhibition, storage, preventive conservation, and restoration. The scope has widened from art conservation, involving protection and care of artwork and architecture, to conservat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
