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Dendrochronology
Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood. Dendrochronology derives from Ancient Greek (), meaning "tree", (), meaning "time", and (), "the study of". Dendrochronology is useful for determining the precise age of samples, especially those that are too recent for radiocarbon dating, which always produces a range rather than an exact date. However, for a precise date of the death of the tree a full sample to the edge is needed, which most trimmed timber will not provide. It also gives data on the timing of events and rates of change in the environment (most prominently climate) and also in wood found in archaeology or works of art and architecture, such as old panel paintings. It is also used as a check in radioc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrochronological Drill Hg
Dendrochronology (or tree-ring dating) is the scientific method of chronological dating, dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood. Dendrochronology derives from Ancient Greek (), meaning "tree", (), meaning "time", and (), "the study of". Dendrochronology is useful for determining the precise age of samples, especially those that are too recent for radiocarbon dating, which always produces a range rather than an exact date. However, for a precise date of the death of the tree a full sample to the edge is needed, which most trimmed timber will not provide. It also gives data on the timing of events and rates of change in the environment (most prominently climate) and also in wood found in archaeology or works of art and architecture, such as old panel paintings. It is also used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendroclimatology
Dendroclimatology is the science of determining past climates from trees (primarily properties of the annual tree rings). Tree rings are wider when conditions favor growth, narrower when times are difficult. Other properties of the annual rings, such as maximum latewood density (MXD) have been shown to be better proxies than simple ring width. Using tree rings, scientists have estimated many local climates for hundreds to thousands of years previous. By combining multiple tree-ring studies (sometimes with other climate proxy records), scientists have estimated past regional and global climates. Advantages Tree rings are especially useful as climate proxies in that they can be well-dated via dendrochronology, i.e. matching of the rings from sample to sample. This allows extension backwards in time using deceased tree samples, even using samples from buildings or from archeological digs. Another advantage of tree rings is that they are clearly demarked in annual increments, as op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calibration Of Radiocarbon Dates
Radiocarbon dating measurements produce ages in "radiocarbon years", which must be converted to calendar ages by a process called calibration. Calibration is needed because the atmospheric / ratio, which is a key element in calculating radiocarbon ages, has not been constant historically.Taylor (1987), p. 133. Willard Libby, the inventor of radiocarbon dating, pointed out as early as 1955 the possibility that the ratio might have varied over time. Discrepancies began to be noted between measured ages and known historical dates for artefacts, and it became clear that a correction would need to be applied to radiocarbon ages to obtain calendar dates. Uncalibrated dates may be stated as "radiocarbon years ago", abbreviated "ya". The term Before Present (BP) is established for reporting dates derived from radiocarbon analysis, where "present" is 1950. Uncalibrated dates are stated as "uncal BP", and ''calibrated'' (corrected) dates as "cal BP". Used alone, the term BP is am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panel Painting
A panel painting is a painting made on a flat panel of wood, either a single piece or a number of pieces joined together. Until canvas became the more popular support medium in the 16th century, panel painting was the normal method, when not painting directly onto a wall (fresco) or on vellum (used for miniatures in illuminated manuscripts). Wood panels were also used for mounting vellum paintings. History Panel painting is very old; it was a very prestigious medium in Greece and Rome, but only very few examples of ancient panel paintings have survived. A series of 6th century BC painted tablets from Pitsa (Greece) represent the oldest surviving Greek panel paintings. Most classical Greek paintings that were famous in their day seem to have been of a size comparable to smaller modern works – perhaps up to a half-length portrait size. However, for a generation in the second quarter of the fifth-century BC there was a movement, called the "new painting" and led by Polygnotus, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive 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 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 wood or a fragment of bone, provides information that can be used to ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronological Dating
Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established chronology. This usually requires what is commonly known as a "dating method". Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using such techniques are, for example, history, archaeology, geology, paleontology, astronomy and even forensic science, since in the latter it is sometimes necessary to investigate the moment in the past during which the death of a cadaver occurred. These methods are typically identified as absolute, which involves a specified date or date range, or relative, which refers to dating which places artifacts or events on a timeline relative to other events and/or artifacts. Other markers can help place an artifact or event in a chronology, such as nearby writings and stratigraphic markers. Absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacob Kuechler
Jacob Kuechler (1823–1893) was surveyor, conscientious objector during the Civil War, and commissioner of the Texas General Land Office. Kuechler pioneered the science of Dendrochronology to date natural events. Early life and education Jacob Kuechler, was born in Schoellenbach, Hesse-Darmstadt, on February 18, 1823, to engineering and forestry official Albrecht Kuechler. Jacob Kuechler graduated from the University of Giessen with degrees in Civil Engineering and Forestry. Texas Kuechler arrived in Galveston on July 4, 1847, on the ship ''St. Pauli ''from Hamburg. He was part of the Darmstadt free-thinker fraternity of intellectuals from the universities of Giessen and Heidelberg and the Gewerbeschule of Darmstadt. They founded the Fisher–Miller Land Grant community of Bettina, Texas after John O. Meusebach negotiated the Meusebach–Comanche Treaty in 1847. Bettina failed after the Adelsverein funding expired, and due to conflict of structure and authorities. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercus Stellata
''Quercus stellata'', the post oak or iron oak, is a North American species of oak in the white oak section. It is a slow-growing oak that lives in dry areas on the edges of fields, tops of ridges also grows in poor soils, and is resistant to rot, fire, and drought. Interbreeding occurs among white oaks, thus many hybrid species combinations occur. The species is native to the eastern and central United States, and found along the east coast from Massachusetts to Florida, and as far inland as Nebraska. It is identifiable by the rounded cross-like shape formed by the leaf lobes and hairy underside of the leaves. Description Post oak is a relatively small tree, typically tall and trunk in diameter, though occasional specimens reach tall and in diameter. The leaves have a very distinctive shape, with three perpendicular terminal lobes, shaped much like a Maltese cross. They are leathery, and tomentose (densely short-hairy) beneath. The branching pattern of this tree often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Babbage is considered by some to be " father of the computer". Babbage is credited with inventing the first mechanical computer, the Difference Engine, 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, programmed using a principle openly borrowed from the Jacquard loom. Babbage had a broad range of interests in addition to his work on computers covered in his book ''Economy of Manufactures and Machinery''. His varied work in other fields has led him to be described as "pre-eminent" among the many polymaths of his century. Babbage, who died before the complete successful engineering of many of his designs, including his Difference Engine and Analytical En ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The American Journal Of Science
The ''American Journal of Science'' (''AJS'') is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself. Until 1880, it was also known as the ''American Journal of Science and Arts'', but its focus was always on natural sciences and especially on geology and related subjects. In early years, the journal was often referred to as "Silliman's Journal", and the publication became associated with Yale University due to his long tenure there (1804–1853). The editorship long remained in the family of Professor Silliman, as he was assisted by his son, Benjamin Silliman Jr., from 1838. On the death of the elder Silliman in 1864, he was succeeded as chief editor by his son-in-law, James Dwight Dana, and then from 1895 till 1926 by Dana's son Edward Salisbury Dana. Associate editors included the botanist Asa Gray and the zoologist Louis Agassiz. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Catlin Twining
Alexander Catlin Twining (July 5, 1801 – November 22, 1884) was an American scientist and inventor. Twining, the son of Stephen Twining and Almira (Catlin) Twining, was born in New Haven, Connecticut, July 5, 1801. He graduated from Yale College in 1820. He left College with the intention of entering the ministry, and soon after studied for one year in Andover Theological Seminary. In 1823 he returned to New Haven as tutor in at Yale, in which office he served for two years. Meanwhile he had decided to become a civil engineer, and now went to West Point to prepare himself for his profession. He was first employed upon the State works of Pennsylvania, and his earliest independent work was in 1835–37 as chief of the survey for the Hartford and New Haven Railroad; he was subsequently employed either as chief or consulting engineer upon every railroad running out of New Haven (excepting possibly the Derby road). In like manner he was employed on the northern lines running up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonardo Da Vinci
Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested on his achievements as a painter, he also became known for his notebooks, in which he made drawings and notes on a variety of subjects, including anatomy, astronomy, botany, cartography, painting, and paleontology. Leonardo is widely regarded to have been a genius who epitomized the Renaissance humanist ideal, and his collective works comprise a contribution to later generations of artists matched only by that of his younger contemporary, Michelangelo. Born out of wedlock to a successful notary and a lower-class woman in, or near, Vinci, he was educated in Florence by the Italian painter and sculptor Andrea del Verrocchio. He began his career in the city, but then spent much time in the service of Ludovico Sforza in Milan. Later, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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