|
1952 In Science
The year 1952 in science and technology involved some significant events, listed below. Biology * August 1 – Around 9 o'clock AM Pacific Time Zone, the San Benedicto rock wren goes extinct as its island home is smothered in a massive volcanic eruption. * August 14 – Alan Turing's paper "The Chemical Basis of Morphogenesis" is published, putting forward a reaction–diffusion hypothesis of pattern formation, considered a seminal piece of work in morphogenesis. * August 28 – Alan Hodgkin and Andrew Huxley publish the Hodgkin–Huxley model of action potentials in neurons of the squid giant axon. * September 20 – Publication of the paper on the Hershey–Chase experiment showing conclusively that DNA, not protein, is the genetic material of bacteriophages. * October – Danish virologist Preben von Magnus publishes his observation of the von Magnus phenomenon producing defective interfering particles. * Biochemists Jack Gross and Rosalind Pitt-Rivers discover the thyr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Benedicto Rock Wren
The San Benedicto rock wren (''Salpinctes obsoletus exsul'') is a small extinct passerine which was endemic to San Benedicto Island in the Revillagigedo Islands off Mexico. It was a subspecies of the rock wren. Extinction San Benedicto is a volcano, like all the Revillagigedo group. Unlike, for example, Roca Partida, it was still active in recent times. On August 1, 1952, lava fountains started to break out of the Boquerón vent, located in a rift between the two older volcano cones. By around 8:45, ejecta were thrown up for several km in a severe vulcanian eruption of magnitude 3 on the Volcanic Explosivity Index scale; pyroclastic flows rolled over the island. Two weeks later, the entire island was covered in ash and pumice up to 10 ft (3 m) deep. Bárcena crater, nearly 1100 ft high (over 300 m), rose where the wren's habitat had previously existed. The birds were never seen again. This rock wren was the only endemic terrestrial bird on San Benedicto. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chance Seedling
A chance seedling is a plant that is the product of unintentional breeding. Identifying the parent plants of a chance seedling may be difficult. It may be necessary to genetically analyse the seedling and surrounding plants to be sure. Plants that come from the artificial union of gametes from a maternal and paternal source are not chance seedlings. A chance seedling may be a genetically unique individual with desirable characteristics that is then intentionally bred. The Kindred Spirit Hybrid Oak and the Granny Smith, Wolf River, Lady Alice, Red Delicious, Gravenstein, Braeburn, Samarbehisht Chausa, Calville Blanc d'hiver, Belle de Boskoop and Baldwin apples are examples of varieties that started with chance seedlings that were selected and assigned cultivar status owing to their desirable properties. See also *Volunteer (botany) In gardening and agronomic terminology, a volunteer is a plant that grows on its own, rather than being deliberately planted by a farmer or gardener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from purposeful human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word ''cultivar''''Cultivar'' () has two meanings, as explained in ''Formal definition'': it is a classification category and a taxonomic unit within the category. When referring to a taxon, the word does not apply to an individual plant but to all plants that share the unique characteristics that define the cultivar. was coined as a term meaning "cultivated variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braeburn
The Braeburn is a cultivar of apple that is firm to the touch with a red/orange vertical streaky appearance on a yellow/green background. Its color intensity varies with different growing conditions. It was discovered as a chance seedling in 1952 by the farmer O. Moran from Waiwhero in the Moutere Hills near Motueka, New Zealand. It was then cultivated by the Williams Brothers nursery as a potential export variety. A study published in 2020 indicated Braeburn is the offspring of Delicious and Sturmer Pippin, with Lady Hamilton as a sibling. The apple itself is named after Braeburn Orchard near Motueka, where it was first commercially grown. Braeburn apples have a combination of sweet and tart flavor. They are available October through April in the northern hemisphere and are medium to large in size. They are a popular fruit for growers because of their ability to store well when chilled. Braeburn apples are useful in cooking as they hold their shape and do not release a gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Lancet
''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823. The journal publishes original research articles, review articles ("seminars" and "reviews"), editorials, book reviews, correspondence, as well as news features and case reports. ''The Lancet'' has been owned by Elsevier since 1991, and its editor-in-chief since 1995 has been Richard Horton. The journal has editorial offices in London, New York City, and Beijing. History ''The Lancet'' was founded in 1823 by Thomas Wakley, an English surgeon who named it after the surgical instrument called a lancet (scalpel). Members of the Wakley family retained editorship of the journal until 1908. In 1921, ''The Lancet'' was acquired by Hodder & Stoughton. Elsevier acquired ''The Lancet'' from Hodder & Stoughton in 1991. Impact According to the ''Journal Citation Reports'', the journal has a 202 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triiodothyronine
Triiodothyronine, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate. Production of T3 and its prohormone thyroxine (T4) is activated by thyroid-stimulating hormone (TSH), which is released from the anterior pituitary gland. This pathway is part of a closed-loop feedback process: Elevated concentrations of T3, and T4 in the blood plasma inhibit the production of TSH in the anterior pituitary gland. As concentrations of these hormones decrease, the anterior pituitary gland increases production of TSH, and by these processes, a feedback control system stabilizes the level of thyroid hormones in the bloodstream. T3 is the true hormone. Its effects on target tissues are roughly four times more potent than those of T4. Of the thyroid hormone that is produced, just about 20% is T3, whereas 80% is produced as T4. Roughly 85% of the circulating T3 is later fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroid Hormone
File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4 rect 376 268 820 433 Thyroid-stimulating hormone rect 411 200 849 266 Thyrotropin-releasing hormone rect 297 168 502 200 Hypothalamus rect 66 216 386 256 Anterior pituitary gland rect 66 332 342 374 Negative feedback rect 308 436 510 475 Thyroid gland rect 256 539 563 635 Thyroid hormones rect 357 827 569 856 Catecholamine rect 399 716 591 750 Metabolism desc bottom-left Thyroid hormones are any hormones produced and released by the thyroid gland, namely triiodothyronine (T3) and thyroxine (T4). They are tyrosine-based hormones that are primarily responsible for regulation of metabolism. T3 and T4 are partially composed of iodine. A deficiency of iodine leads to decreased production of T3 and T4, enlarges the thyroid tissue and will cause the disease known as simple goitre. The major form of thyroid hormone in the blood is thyroxine (T4), whose half-life of around one week is longer th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosalind Pitt-Rivers
Rosalind Venetia Lane Fox Pitt-Rivers FRS ( Henley; 4 March 1907 – 14 January 1990) was a British biochemist. She became the second president of the European Thyroid Association in 1971; she succeeded Jean Roche and was followed by Jack Gross in this position, all three names inextricably linked with the discovery of the thyroid hormone triiodothyronine (T3). Early life and education Pitt-Rivers was born Rosalind Venetia Henley on 4 March 1907 at 18 Mansfield Street, London, the eldest of four daughters of the Hon. Anthony Morton Henley (1873–1925), a Captain in the 5th Lancers, and his wife the Hon. Sylvia Laura Stanley (1882–1980). Her father was the third son of Anthony Henley, 3rd Baron Henley and her mother the daughter of Lord Stanley of Alderley. She was educated at home and later at Notting Hill High School at the age of thirteen. Her interest in chemistry began at the age of twelve when an uncle gave her a chemistry set. She later studied at Bedford Colle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archiv Für Die Gesamte Virusforschung
The ''Archives of Virology'' is a peer-reviewed scientific journal covering research in virology. It is published by Springer Science+Business Media and is the official journal of the Virology Division of the International Union of Microbiological Societies. It was established in 1939 as the ''Archiv für die gesamte Virusforschung'' and obtained its current title in 1975. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 2.574. References External links * Monthly journals English-language journals Publications established in 1939 Springer Science+Business Media academic journals Virology journals {{virology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defective Interfering Particle
Defective interfering particles (DIPs), also known as defective interfering viruses, are spontaneously generated virus mutants in which a critical portion of the particle's genome has been lost due to defective replication or non-homologous recombination. The mechanism of their formation is presumed to be as a result of template-switching during replication of the viral genome, although non-replicative mechanisms involving direct ligation of genomic RNA fragments have also been proposed. DIPs are derived from and associated with their parent virus, and particles are classed as DIPs if they are rendered non-infectious due to at least one essential gene of the virus being lost or severely damaged as a result of the defection. A DIP can usually still penetrate host cells, but requires another fully functional virus particle (the 'helper' virus) to co-infect a cell with it, in order to provide the lost factors. DIPs were first observed as early as the 1950s by Von Magnus and Schlesinge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Magnus Phenomenon
The von Magnus phenomenon describes the generation of defective interfering particles (DIPs) by viruses. It was first observed by Preben von Magnus in influenza viruses, after the serial passage of undiluted allantoic fluid in eggs. References {{reflist Virology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Cultivar")
