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Peter Boysen Jensen
Peter Boysen Jensen (18 January 1883 – 21 November 1959) was a Danish plant physiologist. His research was fundamental to further work on the auxin theory of tropisms. Early life and education Peter was born in Hjerting, near Esbjerg in southern Jutland. Being raised on a farm, he discovered early his affinity to nature. He studied botany during his first premed year, and decided to focus on plant physiology after being influenced by ecologist Eugenius Warming. (1840–1905) and Wilhelm Johannsen (1857–1927) were Boysen Jensen's plant physiology teachers and advisors. While he was a college student in Copenhagen however, neither of these was actively involved in experimental plant physiology. In 1908, Boysen Jensen earned the degree of ''magister scientiarum''. He spent three months of the following year in Wilhelm Pfeffer's Leipzig lab and another four with the biochemist Ernst Schulze in Zürich. Boysen Jensen completed his doctoral studies in 1910, with the thesis ''Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hjerting
Hjerting is a district of Esbjerg in southwest Jutland, Denmark, some north of the centre. As of 2011, it has 7,289 inhabitants. With a history as a fishing village going back some 700 years it is now an exclusive suburb with views over the sandy beach and the Wadden Sea. History Hjerting has a history going back over 700 years. It was originally a fishing village and port for Varde. In the mid-19th century, meat was exported from Hjerting to England until Esbjerg Harbour was developed. The housing estate which has been extended since 1960 is located on the coast with views out to the Skallingen peninsula. Hjerting Church, completed in 1992, was designed by Alan Havsteen-Mikkelsen. The district today Today Hjerting is a pleasant seaside resort and an exclusive suburb overlooking the bay of Ho Bugt on the Wadden Sea. In addition to the views out over the bay, the main attraction is the sandy beach which has a reddish colour. Thanks to the Skallingen peninsula to the west, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Danish Academy Of Sciences And Letters
The Royal Danish Academy of Sciences and Letters ({{Langx, da, Det Kongelige Danske Videnskabernes Selskab or ''Videnskabernes Selskab'') is a Danish academy of science. The Royal Danish Academy was established on 13 November 1742, and was created with the purpose of strengthening the position of Science in Denmark as well as promoting interdisciplinary understanding. The Royal Danish Academy works as a body of cooperation and a meeting place for prominent scientists from all areas of basic scientific research. Its core activities consist of organizing the biweekly meetings for the academy's members, publishing scientific works, advising, and communicating, organizing and conducting events and lectures of a scientific character (e.g. public lectures and symposiums) as well as participating in international cooperation with other scientific academies and with scientific organizations like for example ISC and EASAC. Since 1745, the Royal Danish Academy has had its own publishing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1959 Deaths
Events January * January 1 – Cuba: Fulgencio Batista flees Havana when the forces of Fidel Castro advance. * January 2 – Soviet lunar probe Luna 1 is the first human-made object to attain escape velocity from Earth. It reaches the vicinity of Earth's Moon, where it was intended to crash-land, but instead becomes the first spacecraft to go into heliocentric orbit. * January 3 ** Alaska is admitted as the 49th U.S. state. ** The southernmost island of the Maldives archipelago, Addu Atoll, declares its independence from the Kingdom of the Maldives, initiating the United Suvadive Republic. * January 4 ** In Cuba, rebel troops led by Che Guevara and Camilo Cienfuegos enter the city of Havana. ** Léopoldville riots: At least 49 people are killed during clashes between the police and participants of a meeting of the ABAKO Party in Kinshasa, Léopoldville in the Belgian Congo. * January 6 – The International Maritime Organization is inaugurated. * January 7 – The United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1883 Births
Events January * January 4 – ''Life (magazine), Life'' magazine is founded in Los Angeles, California, United States. * January 10 – A Newhall House Hotel Fire, fire at the Newhall Hotel in Milwaukee, Wisconsin, United States, kills 73 people. * January 16 – The Pendleton Civil Service Reform Act, establishing the United States civil service, is passed. * January 19 – The first electric lighting system employing overhead wires begins service in Roselle, New Jersey, United States, installed by Thomas Edison. February * February 15 – Tokyo Electrical Lightning Grid, predecessor of Tokyo Electrical Power (TEPCO), one of the largest electrical grids in Asia and the world, is founded in Japan. * February 16 – The ''Ladies' Home Journal'' is published for the first time, in the United States. * February 23 – Alabama becomes the first U.S. state to enact an Competition law, antitrust law. * February 28 – The first vaudeville th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mica
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are used in products such as drywalls, paints, and fillers, especially in parts for automobiles, roofing, and in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost". Properties and structure The mica group comprises 37 phyllosilicate minerals. All crystallize in the monoclinic system, with a tendency towards pseudohexagonal crystals, and are similar in structure but vary in chemical composition. Micas are translucent to opa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stimulus (physiology)
In physiology, a stimulus is a change in a living thing's internal or external environment. This change can be detected by an organism or organ using sensitivity, and leads to a physiological reaction. Sensory receptors can receive stimuli from outside the body, as in touch receptors found in the skin or light receptors in the eye, as well as from inside the body, as in chemoreceptors and mechanoreceptors. When a stimulus is detected by a sensory receptor, it can elicit a reflex via stimulus transduction. An internal stimulus is often the first component of a homeostatic control system. External stimuli are capable of producing systemic responses throughout the body, as in the fight-or-flight response. In order for a stimulus to be detected with high probability, its level of strength must exceed the absolute threshold; if a signal does reach threshold, the information is transmitted to the central nervous system (CNS), where it is integrated and a decision on how to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocotyl
The hypocotyl (short for "hypocotyledonous stem", meaning "below seed leaf") is the stem of a germinating seedling, found below the cotyledons (seed leaves) and above the radicle (root). Eudicots As the plant embryo grows at germination, it sends out a shoot called a radicle that becomes the primary root, and then penetrates down into the soil. After emergence of the radicle, the hypocotyl emerges and lifts the growing tip (usually including the seed coat) above the ground, bearing the embryonic leaves (called cotyledons), and the plumule that gives rise to the first true leaves. The hypocotyl is the primary organ of extension of the young plant and develops into the stem. Monocots The early development of a monocot seedling like cereals and other grasses is somewhat different. A structure called the coleoptile, essentially a part of the ''cotyledon'', protects the young stem and plumule as growth pushes them up through the soil. A mesocotyl—that part of the young plant that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phototropism
In biology, phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light contain a hormone called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one of the many plant tropisms, or movements, which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Negative phototropism is not to be confused with skototropism, which is defined as the growth towards darkness, whereas negative phototropism can refer to either the growth away from a light source or towards the darkness. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth.G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coleoptile
Coleoptile is the pointed protective sheath covering the emerging shoot in monocotyledons such as grasses in which few leaf primordia and shoot apex of monocot embryo remain enclosed. The coleoptile protects the first leaf as well as the growing stem in seedlings and eventually, allows the first leaf to emerge. Coleoptiles have two vascular bundles, one on either side. Unlike the flag leaves rolled up within, the pre-emergent coleoptile does not accumulate significant protochlorophyll or carotenoids, and so it is generally very pale. Some preemergent coleoptiles do, however, accumulate purple anthocyanin pigments. Coleoptiles consist of very similar cells that are all specialised to fast stretch growth. They do not divide, but increase in size as they accumulate more water. Coleoptiles also have water vessels (frequently two) along the axis to provide a water supply. When a coleoptile reaches the surface, it stops growing and the flag leaves penetrate its top, continuing to grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis Darwin
Sir Francis Darwin (16 August 1848 – 19 September 1925) was a British botanist. He was the third son of the naturalist and scientist Charles Darwin. Biography Francis Darwin was born at Down House, Downe, Kent in 1848. He was the third son and seventh child of Charles Darwin and his wife Emma Wedgwood. He was educated at Clapham Grammar School. He then went to Trinity College, Cambridge, initially studying mathematics, then changing to natural sciences, graduating in 1870. He then went to study medicine at St George's Medical School, London, earning an MB in 1875, but did not practice medicine. Darwin was married three times and widowed twice. First, he married Amy Richenda Ruck in 1874, but she died in 1876 four days after the birth of their son Bernard Darwin, who was later to become a golf writer. In September 1883, he married Ellen Wordsworth Crofts (1856–1903) and they had a daughter Frances Crofts Darwin (1886–1960), a poet who married the poet Francis Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a Common descent, common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation with Alfred Russel Wallace, he introduced his scientific theory that this Phylogenetics, branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.. Darwin has been described as one of the most influential figures in human history and was honoured by Burials and memorials in Westminster Abbey, burial in Westminster Abbey. Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh Medical Schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
