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42,727,389 | https://en.wikipedia.org/wiki/Kuhn%27s%20theorem | In game theory, Kuhn's theorem relates perfect recall, mixed and unmixed strategies and their expected payoffs. It is named after Harold W. Kuhn.
The theorem states that in a game where players may remember all of their previous moves/states of the game available to them, for every mixed strategy there is a behavioral strategy that has an equivalent payoff (i.e. the strategies are equivalent). The theorem does not specify what this strategy is, only that it exists. It is valid both for finite games, as well as infinite games (i.e. games with continuous choices, or iterated infinitely).
References
Game theory
Mathematical economics
Economics theorems | Kuhn's theorem | [
"Mathematics"
] | 140 | [
"Applied mathematics",
"Game theory",
"Mathematical economics"
] |
42,729,017 | https://en.wikipedia.org/wiki/Multiclavula%20vernalis | Multiclavula vernalis or the orange club-mushroom lichen is a species of clavarioid fungus in the Clavulinaceae (club-mushroom lichen) family. It was originally named as a species of Clavaria in 1822 by Lewis David de Schweinitz. Ronald H. Petersen transferred it to Multiclavula in 1967.
References
External links
Clavulinaceae
Fungi described in 1822
Fungi of Europe
Fungi of North America
Taxa named by Ron Petersen
Taxa named by Lewis David de Schweinitz
Basidiolichens
Fungus species | Multiclavula vernalis | [
"Biology"
] | 117 | [
"Fungi",
"Fungus species"
] |
42,729,108 | https://en.wikipedia.org/wiki/John%20Marriott%20Blashfield | John Marriott Blashfield (1811–1882) was a property developer and mosaic floor and ornamental terracotta manufacturer. He originally worked for the cement makers Wyatt, Parker and & Co in Millwall, but moved the business to Stamford in Lincolnshire in 1858, when it was renamed The Stamford Terracotta Company.
Early career
Blashfield was Mintons representative in London and a partner in the firm of Wyatt, Parker & Co of Millwall, manufacturers of cement, scagliola and mosaic pavements, which he took over in 1846. In 1843 he published a small booklet on mosaics he had designed and in 1843/45 he was responsible for the mosaic floor at the old Conservative Club in St James's Street, London. He became interested in the manufacture of terracotta around 1839 when he engaged J. G. Bubb on experimental terracotta work for model cottages at Canford Magna, Dorset. This appears to have led to his manufacturing terracotta ornamentation for buildings. In the early 1840s he supplied an extensive series of gothic terracotta mouldings for the English church at Bagni di Lucca in Tuscany. In the mid 1840s he started working with leading English sculptors, most notably John Bell and William Theed the Younger, for whom he produced terracotta versions of sculptures which were originally sculpted in marble or cast in iron. Blashfield was well connected and patronised by some of the leading architects, particularly the Wyatts, Sydney Smirke and Charles Barry Jr. Blashfield also derived many of his ideas for designs from the architects and illustrators Owen Jones and James Kellaway Colling. As result of the popularity of terracotta pieces at the Great Exhibition of 1851, he turned increasingly towards the manufacture of garden furniture, parapets and urns. It has been claimed that at about this time he purchased the moulds from Eleanor Coade's Lambeth works that had been used to produce Coade Stone, but this has been disputed as Coade's bankruptcy was some years before and few of his designs resemble those of Coade, except for the shape of some of the urns. The buff colour and texture of Blashfield's Terracotta can resemble the appearance of Coade stone. Blashfield's main works was in Millwall but he had showrooms at Praed Street adjacent to the Edgware Road in Paddington. In the 1851 Balshfield was still describing himself as a “cement manufacturer’’ and at that time was employing 5 Clerks and 35 Men.
With the reconstruction of the Crystal Palace at Sydenham in 1854 Blashfield was awarded the contract, to cast a series of colossal terracotta statues representing Australia, California, Birmingham and Sheffield by John Bell for display in the sculpture gallery at Crystal Palace. The sculptures were later destroyed when the Crystal Palace was burnt down. To publicise his terracottas Blashfield published in 1855 An Account of the History and Manufacture of Ancient and Modern Terra Cotta and several catalogues, including A Catalogue of Five Hundred Articles in 1857. These terracottas included replicas of classical statuary and vases, such as the Niobe group in the Uffizi and the Borghese and Medici vases. Blashfield was proud of the fact that his products were hand-finished and taken from the best moulds.
Development of Kensington Palace Gardens
The Queen’s Road came into existence in 1841 when the Crown Estate sold off land which had formerly been part of the kitchen gardens of Kensington Palace. The Commissioners of Woods and Forests took charge of the letting of this newly available land and they planned for a series of detached villas, each situated within its own plot of land. Blashfield leased twenty of the thirty-three plots for building in July 1843. Blashfield’s first house was one of the most notable of the entire street. Built between 1843–6, No.8 Kensington Palace Gardens was designed by Owen Jones (1809–1874). Influenced by Islamic architecture he encountered in Egypt, Turkey and Spain during his early twenties. Jones’s plans for the house included a significant amount of ‘Moresque’ design. After this Blashfield struggled to find buyers for his houses, eventually going bankrupt in 1847. He appears to have kept this enterprise separate from his manufacturing business and continued to develop the latter.
Stamford Terracotta Company
In 1859 terracotta production was transferred from London to Stamford, Lincolnshire, in order to exploit the local Jurassic clays, which were particularly suitable for terracotta production. The Wharf Road works were considerably larger than Blashfield's London premises and in the 1861 census he was calling himself Terra Cotta Manufacturer and Pottery Company and was employing 46 Men and 13 Boys.
Most of the clay he used was from brickyards in the vicinity of Stamford at Wakerley, and Uffington, and Lower Estuarine clays from St Martin's, Stamford, but he still imported some Ball clays via Poole in Dorset and elsewhere from clay pits near the south coast.
Blashfield had taken over Grant's Iron foundry in Stamford, which was in Wharf Road and adjacent to the river Welland, which was convenient for bringing clay in and shipping terracotta out. The gateway to Blashfield's Terracotta works, which was formerly the gateway to Grant's Ironworks still stands in Wharf Road in Stamford, although it has been slightly re-positioned.
The opening of the new works attracted considerable public interest. The local aristocracy attended the drawing of the first kiln and one of the busts of the Queen that had been fired was presented to her the following day. In 1865 the firm made a statue of Prince Albert from a model by William Theed the younger for the infirmary at Bishop's Waltham, Hants. It was of ‘clays from the estate of Mr Arthur Helps, at Bishops Waltham, and clay from the Marquis of Exeter’s celebrated pit at Wakerley, mixed with feldspar and Lynn sand’ and was assembled inside the kiln and fired in one piece. It emerged from the kiln ‘without flaw’ and ‘as hard as black marble’. This use of complex blends of ingredients and the highly wrought finish were typical of Blashfield's scientific approach to terracotta production.
Attempted expansion into the American market and bankruptcy
While still in London Blashfiield had been working with the architect and designer James Kellaway Colling who was an associate or partner of the American architect John Hubbard Sturgis. When Sturgis returned to Boston in the US in 1861, he started importing terracotta from Stamford for his first project "Pinebank" near Boston. This was followed by the much more prestigious project, supplying terracotta ornament and decorative panels (designed by Colling) for the Museum of Fine Arts in Boston. He seriously underestimated the logistical difficulties involved in shipping large consignments of fragile blocks across the Atlantic. He soon realised that he had accepted an uneconomic contract and his company began to incur serious debts when payments were delayed. Delivery of one consignment was held back when a ship had to turn back to England and other payments were delayed when the building contractors were unable to relate the pieces supplied to the intended spaces on the building. From the beginning of 1873 Blashfield was requesting money from his American clients with increasing desperation and by December 1874 the Stamford works, including models, moulds and machinery, was offered for sale. In the following month Blashfield announced that the firm was being wound up and he was declared bankrupt in 1878. After the collapse of the business a number of Blashfield's former employees emigrated to America, where they played an important role in the introduction of architectural terracotta. He died "after a short illness of bronchitis followed by paralysis" on 15 December 1882.
Blashfield's work in Stamford
Some buildings in Stamford would appear to be using Blashfield's terracotta for decorative dressing, most notably the former Scotgate Inn. This is a two-storey building formerly used as a depot for P & R Phipps. Parapet with panels at quoins supporting carved urns, with the name 'P & R Phipps, Brewers' below crest of castle with lion supporters and motto. Head of Hermes over doorway and carriage door to right of eight panels, vermiculated rusticated arch with monogram on keystone. It is also used for a shop at 30 High Street.
Some terracotta production was carried out in Stamford apart from at Blashfield's works. Henry Lumby was noted as a terracotta manufacturer on a site in St Martin's, Stamford in 1868 and 1872 and in 1863 Charles Joseph Whitton had a works in London Road.
Awards
1862 Medal awarded – International Exhibition.
1865 Medal Awarded – Dublin International Exhibition.
1867 Medal Awarded – Paris Exhibition.
Publications and trade catalogues
Source:
1843 Tesselated Pavements designed by J. M. Blashfield. Six plates
1855 An account of the history and manufacture of ancient and modern terra cotta; And of its use in architecture as a durable and elegant material for decoration. London : Published by John Weale, 59, High Holborn
1857 A Selection of Vases, Statues, Busts, & c. from Terra-Cottas. Plates, with an introduction. Published by John Weale, 59, High Holborn
1857 A catalogue of five hundred articles, made of patent Terra cotta. London.
1859 Ancient and modern pottery a paper read at Stamford, 6 September 1859
1860 A catalogue of seven hundred articles: Made in patent terra cotta, and red and cane-coloured pottery..
1868 Terra Cotta Chimney Shafts, Chimney Pots, (8 Plates)., manufactured by J. M. Blashfield bound with Examples of Terracotta Balustrades, Panels or Perforated Tracery Ornament, Terminals, etc. for Parapets, Terraces etc. (8 Plates). bound with ‘‘Domestic Architecture:Terra Cotta Doorways, Windows, Balconies, Consoles, Copings, Plinths, Date and Monogram Panels etc.. (8 Plates), bound with ‘‘Examples of Terra Cotta Consoles, Trusses, Console Cappings, Brackets, Pilasters, &c for Doorways, Windows, Shop Fronts &c (8 Plates) bound with Examples of Terra Cotta Cornices, String Courses, Moulded Bricks Etc. (8 Plates)Published by J.M. Blashfield, Stamford, January 1868–
Examples of Blashfields Work
Dated work
1843–45. Mosaic flooring in the saloon of the old Conservative Club, St James's Street, London SW1. Sydney Smirke and George Basevi, 1843–45; mosaic by John Marriott Blashfield.
1856. Albany, Liverpool. Possible use of Blashfield’s Terracotta for friezes and dressings. Designs by J. K. Colling.
1859 Garthmyl Hall, Berriew, Montgomeryshire. Designs by J. K. Colling. Ornamental friezes and consoles. Coat of arms with foliage and roses.
1854 Crystal Palace, Sydenham. Statues of Australia, California, Birmingham and Sheffield (modelled by John Bell)
1854 Triton fountain (modelled by John Bell) for the Radcliffe Infirmary, Oxford.
1863–1873 Wedgwood Institute, Burslem, Stoke-on-Trent. Processes of the pottery industry, relief panels (modelled by Matthew Eden) The terracotta panels of the processes of industry were modelled by Mathew Eden and produced by John Marriott Blashfield.
c1865 Victoria Park, Mumbai (Bombay), India. Entrance gateway and clock-tower.
1865 Duke of Cornwall Hotel, Plymouth, Devon. Decorative terracotta work for the architect C Forster Hayward. When threatened with demolition in 1977 the hotel was described by Sir John Betjeman as "one of the finest examples of Victorian gothic architecture he had ever seen", and in 1988 its future was secured.
1866 Farnham Town Hall, Decorative ornaments.
1866-7 Dulwich College, London. Decorative ornaments designed by Charles Barry Jnr.
1867-8 Terrace gardens, Castle Ashby Park, Castle Ashby – South Northamptonshire. Terraced gardens, to north and east of Castle Ashby House. Designed by Matthew Digby Wyatt with decorated Blashfield terracotta. Fountains, pedestals, balustrades and gate piers
1868-9 Parapets and decorative panels for Sturgis at Pinebank, Boston, Mass.
1871. Scotgate Inn, 5 Scotgate, Stamford. Built for Phipps Brewery of Northampton as a store for wines and spirits. Terracotta rustication and window surrounds, with a parapet inscribed with the name of the brewery. The parapet is surmounted with the arms of Northampton. Now offices.
1875 Replacement of terracotta window mullions and two new windows at Sutton Place, Surrey.
1870-6 Museum of Fine Arts, Boston by Sturgis and Brigham
Undated work
Alford House, Somerset. Decorative ornaments.
Sun Fire Insurance Office, Charing Cross, London.
Royal Mausoleum, Frogmore, Windsor. Urns and possibly the balustrades to the staircase.
Buckingham Palace, London. Vases.
Kew Palace, Surrey. Vases.
Hampton Court Palace.
Stoke Rochford Hall, Lincolnshire. Diana and a Stag. Probably urns and other ornamentation on Orangery.
Stokesay Court, Shropshire. Pair of Warwick Vases.
Ragley Hall, Warwickshire. Pair of classical urns.
Aldermaston Churchyard, Berkshire. Pair of Pineapplle finials.
English Church, Bagni di Lucca, Tuscany, Italy. Royal arms and frieze of roses, shamrocks and thistles. Thermal springs patronised by Byron, Browning and other English tourists. In 1839 permission was granted to build an English church, and Giuseppe Pardini built a church which resembles a palace rather than a church. The three storey building is extensively decorated with reddish terracotta friezes and a prominent ‘gothic’ portico. The building is now used as a library.
Dodington Park, Gloucestershire. Terrace and Urns
Roman Catholic Church of St Mary and St Augustine, Stamford. Terracotta altar rails removed in 1982.
30 High Street, Stamford.
Burghley House, Stamford. Urns in South Garden
Literature
Birch N. Stamford: An Industrial History (1972), Lincolnshire Industrial Archaeology Group.
R. Gunnis Dictionary of British Sculptors, 1660–1851, 1953.
R. Gunnis Dictionary of British Sculptors, 1660–1851, revised ed., 1968
Haskell, Francis, and Penny, Nicholas, Taste and the Antique; The Lure of Classical Sculpture 1500–1900 Yale University Press, New Haven and London: 1981.
Ingrid Roscoe, Emma Hardy & M G Sullivan A Biographical Dictionary of Sculptors in Britain 1660–1851.
The Royal Commission on Historical Monuments of England Inventory of Historical Monuments in the Town of Stamford, HMSO, 1977.
F. H. W. Sheppard (Editor) 'The Crown estate in Kensington Palace Gardens: Individual buildings', Survey of London: Northern Kensington (1973), volume 37pp. 162–193.
Michael Stratton, The Terracotta Revival: Building Innovation and the Image of the Industrial City in Britain and North America, Gollanz, London. 1993.
References
External links
John F. H. Smith, "Blashfield, John Marriott (1811–1882)", Oxford Dictionary of National Biography, Oxford University Press, 2004 accessed 15 Jan 2010
Chris Hill History, Kensington Palace Gardens: The Victorian Creation of an Elite Suburban Street
People from Stamford, Lincolnshire
1811 births
1862 deaths
19th-century English businesspeople
19th-century English landowners
Manufacturer of architectural terracotta | John Marriott Blashfield | [
"Engineering"
] | 3,249 | [
"Manufacturer of architectural terracotta",
"Architecture"
] |
42,729,306 | https://en.wikipedia.org/wiki/AXELOS | AXELOS is a joint venture set up in 2014 by the Government of the United Kingdom and Capita, to develop, manage and operate qualifications in best practice, in methodologies formerly owned by the Office of Government Commerce (OGC). PeopleCert, an examination institute that was responsible for delivering AXELOS exams, acquired AXELOS in 2021.
Portfolio
AXELOS manages:
ITIL (Information Technology Infrastructure Library) – IT Service Management published in 1989 (updated 2000, 2007, 2011 & 2019/20)
PRINCE2 (Projects IN Controlled Environments) – Project Management published in 1996 (updated 1998, 2002, 2005, 2009 & 2017)
MSP (Managing Successful Programmes) – Program Management published in 1999 (updated 2003, 2007, 2011 & 2020)
M_o_R (Management of Risk) – Risk Management published in 2002 (updated 2007 & 2010)
P3M3 or Portfolio, Programme and Project Management Maturity Model published in 2005 (updated 2008 & 2015)
P3O (Portfolio, Programme and Project Offices) published in 2008 (updated 2013)
MoV (Management of Value) – Value Management published in 2010
MoP (Management of Portfolios) – Portfolio Management published in 2011
RESILIApublished in 2015
PRINCE2 Agile – Agile Project Managementpublished in 2015
AgileSHIFT published in 2018
There are third-party training providers, but Axelos manages certification. In April 2014, AXELOS announced that it was also launching a cyber-resilience qualification; this would complement guidance available from CESG.
PeopleCert have been chosen by AXELOS as the sole EI (Examination Institute) for the delivery of Accreditation and Examination services worldwide, starting 1 January 2018.
Background
The portfolio was originally developed for UK government, and is valuable; the government periodically requests tenders for private-sector partners to manage it. Historically, this had been APMG. However, in April 2013 Capita won the contract, under a new arrangement which required them to invest in a joint venture. Capita hold a 51% majority stake, the Cabinet Office the remaining 49%. This joint venture, AXELOS, was formed in July 2013, and it took over from APMG on 1 January 2014.
References
External links
OGC (archived)
Cabinet Office (United Kingdom)
Government procurement in the United Kingdom
Information technology management
Information technology organisations based in the United Kingdom | AXELOS | [
"Technology"
] | 475 | [
"Information technology",
"Information technology management"
] |
42,729,352 | https://en.wikipedia.org/wiki/Early%20Life%20Stage%20test | An early life stage (ELS) test is a chronic toxicity test using sensitive early life stages like embryos or larvae to predict the effects of toxicants on organisms. ELS tests were developed to be quicker and more cost-efficient than full life-cycle tests, taking on average 1–5 months to complete compared to 6–12 months for a life-cycle test. They are commonly used in aquatic toxicology, particularly with fish. Growth and survival are the typically measured endpoints, for which a Maximum Acceptable Toxicant Concentration (MATC) can be estimated. ELS tests allow for the testing of fish species that otherwise could not be studied due to length of life, spawning requirements, or size. ELS tests are used as part of environmental risk assessments by regulatory agencies including the U.S. Environmental Protection Agency (EPA) and Environment Canada, as well as the Organisation for Economic Co-operation and Development (OECD).
Development
ELS tests were adapted from full life-cycle toxicity tests, chronic tests that expose an organism to a contaminant for its entire life-cycle. These are widely considered to be the best tests for estimating long-term "safe" concentrations of toxicants in aquatic organisms. The first full life-cycle tests on fish were developed for the fathead minnow (Pimephales promelas), and later for bluegill (Lepomis macrochirus), brook trout (Salvelinus fontinalis), flagfish (Jordanella floridae), and sheepshead minnow (Cyprinodon variegatus). While useful, full life-cycle tests require a high number of test organisms and extensive exposure time in the lab, especially for vertebrates. Typically, life-cycle tests take 6–12 months for fathead minnow and 30 months for brook trout.
Following the passage of the Toxic Substances Control Act (TSCA) in the United States in 1976, there was an increased need for quicker, more efficient vertebrate toxicity tests. The EPA was now required to assess the environmental effects of new chemicals before they could be commercially produced. Less costly and time-intensive tests were needed to evaluate a multitude of new chemicals. Researchers began developing toxicity tests that focused on early life stages, since these have been shown to be more sensitive to environmental stressors than later life stages. Many critical events occur in a short period of time in the early stages of development. If a stressor disrupts developmental events (including their timing), it could result in adverse effects that reduce the organism's chances of survival. Meta-analysis has found that early life-cycle portions of full life-cycle tests usually estimate an MATC within a factor of 2 of full life-cycle estimates in saltwater and freshwater fish. In 83% of 72 tests, the ELS portion resulted in the same MATC as the full life-cycle estimate, and the remaining 17% were within a factor of 2.
Limitations
There remain some limitations with early life stage toxicity testing. Although ELS tests are quicker and more cost-efficient than full life cycle tests, they remain resource- and time-intensive. Fish early life stage (FELS) tests require hundreds of fish and 1 to 5 months to complete. Other issues include the lack of mechanistic information, differing sensitivities between species, and insensitivity to parental exposure. ELS tests don't provide information on the toxicant's mechanism of action. Sensitivity to specific toxicants varies with species, so the most sensitive or most important species should be tested in each case. ELS tests appear to be insensitive to parental exposure, and MATCs are generally the same for embryos of both exposed and unexposed parents. This could be due to the mode of action of the toxicant or the variability and insensitivity of ELS test design. Additionally, growth response has been found to be an insensitive endpoint in ELS tests with fish, having little bearing on the estimation of an MATC. Growth response could be omitted to reduce the duration and cost of screening tests.
Methodology
In a typical early life stage toxicity test, a flow-through dilutor system administers different concentrations of a toxicant to different test chambers. At least five different concentrations of a toxicant are tested, plus controls, with at least two exposure chambers for each treatment. The length of the exposure depends on the test species. For example, fathead minnow tests are 1–2 months long, while brook trout tests are around 5 months long. Growth and survival are the typical endpoints, for which an MATC can be found.
Standard methods for ELS tests have been established by the OECD, ASTM International, the EPA, and Environment Canada.
Regulatory uses
The FELS guideline of the OECD Guidelines for the Testing of Chemicals is the primary test used internationally to estimate chronic fish toxicity.
FELS tests are part of a suite of sublethal toxicity tests for effluent used by Environment Canada in environmental effects monitoring.
A FELS test is required or recommended by the US EPA for testing and monitoring chemicals released into aquatic systems.
Current developments
An extended ELS test has been examined as a potential surrogate for a fish full life-cycle test to detect weak environmental estrogens. Endocrine active chemicals (EACs) are ubiquitous in the environment, prompting the need for better screening assays to predict their effects, especially in aquatic species. Slightly longer ELS tests could be used instead of full life-cycle tests, taking into account sensitive windows of exposure like sexual differentiation and early gonadal development. Extended ELS tests have proven successful in detecting the effects of weak estrogens in fathead minnows.
Additionally, adverse outcome pathways (AOPs) are being used to develop an alternative to FELS testing. Industry and regulatory agencies are increasingly interested in an animal-free, cost-efficient surrogate. Researchers are developing FELS-related AOPs to create a high-throughput, less costly screening strategy for toxicants that takes the mechanism of action into account.
References
Environmental toxicology
Toxicology tests | Early Life Stage test | [
"Environmental_science"
] | 1,260 | [
"Toxicology tests",
"Toxicology",
"Environmental toxicology"
] |
42,729,826 | https://en.wikipedia.org/wiki/47%20Capricorni | 47 Capricorni is a variable star located around 1,170 light years from the Sun in the southern constellation Capricornus, near the northern border with Aquarius. It has the variable star designation of AG Capricorni and a Bayer designation of c2 Capricorni; 47 Capricorni is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with an apparent visual magnitude that varies between 5.90 and 6.14. The star is receding from the Earth with a heliocentric radial velocity of +20 km/s.
In 1963, Alan William James Cousins announced that 47 Capricorni is a variable star. It was given its variable star designation in 1973.
This is an aging red giant star with a stellar classification of M2III. It is a semiregular variable star of subtype SRb with a period of 30.592 days and a maximum brightness of 5.9 magnitude. With the supply of hydrogen at its core exhausted, the star has expanded to around 102 times the Sun's radius. It is radiating 1,940 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,784 K.
References
M-type giants
Semiregular variable stars
Capricornus
Capricorni, c2
BD-09 5833
Capricorni, 47
207005
107487
8318
Capricorni, AG | 47 Capricorni | [
"Astronomy"
] | 311 | [
"Capricornus",
"Constellations"
] |
42,730,010 | https://en.wikipedia.org/wiki/Tritrophic%20interactions%20in%20plant%20defense | Tritrophic interactions in plant defense against herbivory describe the ecological impacts of three trophic levels on each other: the plant, the herbivore, and its natural enemies. They may also be called multitrophic interactions when further trophic levels, such as soil microbes, endophytes, or hyperparasitoids (higher-order predators) are considered. Tritrophic interactions join pollination and seed dispersal as vital biological functions which plants perform via cooperation with animals.
Natural enemies—predators, pathogens, and parasitoids that attack plant-feeding insects—can benefit plants by hindering the feeding behavior of the harmful insect. It is thought that many plant traits have evolved in response to this mutualism to make themselves more attractive to natural enemies. This recruitment of natural enemies functions to protect against excessive herbivory and is considered an indirect plant defense mechanism. Traits attractive to natural enemies can be physical, as in the cases of domatia and nectaries; or chemical, as in the case of induced plant volatile chemicals that help natural enemies pinpoint a food source.
Humans can take advantage of tritrophic interactions in the biological control of insect pests.
Chemical mechanisms of enemy attraction
Plants produce secondary metabolites known as allelochemicals. Rather than participating in basic metabolic processes, they mediate interactions between a plant and its environment, often attracting, repelling, or poisoning insects. They also help produce secondary cell wall components such as those that require amino acid modification.
In a tritrophic system, volatiles, which are released into the air, are superior to surface chemicals in drawing foraging natural enemies from afar. Plants also produce root volatiles which will drive tritrophic interactions between below-ground herbivores and their natural enemies. Some plant volatiles can be smelled by humans and give plants like basil, eucalyptus, and pine their distinctive odors. The mixture and ratios of individual volatiles emitted by a plant under given circumstances (also referred to as synomones in the context of natural enemy attraction) is referred to as a volatile profile. These are highly specific to certain plant species and are detectable meters from the source. Predators and parasitoids exploit the specificity of volatile profiles to navigate the complex infochemical signals presented by plants in their efforts to locate a particular prey species.
The production of volatiles is likely to be beneficial given two conditions: that they are effective in attracting natural enemies and that the natural enemies are effective in removing or impeding herbivores. However, volatile chemicals may not have evolved initially for this purpose; they act in within-plant signaling, attraction of pollinators, or repulsion of herbivores that dislike such odors.
Induced defenses
When an herbivore starts eating a plant, the plant may respond by increasing its production of volatiles or changing its volatile profile. This plasticity is controlled by either the jasmonic acid pathway or the salicylic acid pathway, depending largely on the herbivore; these substances are often called herbivore-induced plant volatiles (HIPVs). The plant hormone jasmonic acid increases in concentration when plants are damaged and is responsible for inducing the transcription of enzymes that synthesize secondary metabolites. This hormone also aids in the production of defensive proteins such as α-amylase inhibitors, as well as lectins. Since α-amylase breaks down starch, α-amylase inhibitors prevent insects from deriving nutrition from starch. Lectins likewise interfere with insect nutrient absorption as they bind to carbohydrates.
Though volatiles of any kind have an attractive effect on natural enemies, this effect is stronger for damaged plants than for undamaged plants, perhaps because induced volatiles signal definitive and recent herbivore activity. The inducibility gives rise to the idea that plants are sending out a "distress call" to the third trophic level in times of herbivore attack.
Natural enemies can distinguish between mechanical tissue damage, which might occur during events other than herbivory, and damage that is the direct result of insect feeding behavior. The presence of herbivore saliva or regurgitant mediates this differentiation, and the resulting chemical pathway leads to a stronger natural enemy response than mechanical damage could. The reliability of HIPVs in broadcasting the location of prey means that, for many foraging enemies, induced plant volatiles are more attractive than even the odors emitted by the prey insect itself.
Plants are able to determine what types of herbivore species are present, and will react differently given the herbivore's traits. If certain defense mechanisms are not effective, plants may turn to attracting natural enemies of herbivore populations. For example, wild tobacco plants use nicotine, a neurotoxin, to defend against herbivores. However, when faced with nicotine-tolerant herbivores, they will attract natural enemies.
Local and systemic signals
When herbivores trigger an inducible chemical defense pathway, the resulting HIPVs may be emitted either from the site of feeding damage (local induction) or from undamaged tissues belonging to a damaged plant (systemic induction). For example, when an herbivore feeds on a single corn seedling leaf, the plant will emit volatiles from all its leaves, whether or not they too have been damaged. Locally induced defenses aid parasitoids in targeting their foraging behaviors to the exact location of the herbivore on the plant. Systemic defenses are less spatially specific and may serve to confuse the enemy once the source plant is located. A plant might employ both local and systemic responses simultaneously.
Morphological mechanisms of enemy attraction
Domatia
Natural enemies must survive long enough and respond quickly enough to plant volatiles in order to benefit the plant through predatory behavior. Certain plant structures, called domatia, can selectively reinforce mutualisms with natural enemies and increase the fitness benefit they receive from that mutualism by ensuring the survival and proximity of natural enemies. Domatia provide a kind of housing or refuge for predators from both abiotic stressors, such as desiccation, and biotic stressors, such as predation from higher-order predators. Therefore, they not only ensure better survival, but eliminate the time required for natural enemies to locate and travel to the damaged plant. Natural enemies that make use of domatia are often said to serve as "bodyguards" for the plant on or in which they live. Domatia may be as well-developed as acacia tree thorns or as simple and incidental as a depression or crevice in a leaf stem, but they are distinguishable from galls and other similar structures in that they are not induced by the insect but formed constitutively by the plant.
Nutritional rewards
As long as natural enemies have some potential to be omnivorous, plants can provide food resources to encourage their retention and increase the impact they have on herbivore populations. This potential, however, can hinge on a number of the insect's traits. For example, hemipteran predators can use their sucking mouthparts to make use of leaves, stems, and fruits, but spiders with chelicerae cannot. Still, insects widely considered to be purely carnivorous have been observed to diverge from expected feeding behavior. Some plants simply tolerate a low level of herbivory by natural enemies for the service they provide in ridding the plant of more serious herbivores. Others, however, have structures thought to serve no purpose other than attracting and provisioning natural enemies. These structures derive from a long history of coevolution between the first and third trophic levels. A good example is the extrafloral nectaries that many myrmecophytes and other angiosperms sport on leaves, bracts, stems, and fruits. Nutritionally, extrafloral nectaries are similar to floral nectaries, but they do not lead the visiting insect to come into contact with pollen. Their existence is therefore not the product of a pollinator–plant mutualism, but rather a tritrophic, defensive interaction.
Herbivore sequestration of plant defensive compounds
The field of chemical ecology has elucidated additional types of plant multitrophic interactions that entail the transfer of defensive compounds across multiple trophic levels. For example, certain plant species in the Castilleja and Plantago genera have been found to produce defensive compounds called iridoid glycosides that are sequestered in the tissues of the Taylor's checkerspot butterfly larvae that have developed a tolerance for these compounds and are able to consume the foliage of these plants. These sequestered iridoid glycosides then confer chemical protection against bird predators to the butterfly larvae. Another example of this sort of multitrophic interaction in plants is the transfer of defensive alkaloids produced by endophytes living within a grass host to a hemiparasitic plant that is also using the grass as a host.
Human uses
Exploitation of tritrophic interactions can benefit agricultural systems. Biocontrol of crop pests can be exerted by the third trophic level, given an adequate population of natural enemies. However, the widespread use of pesticides or Bt crops can undermine natural enemies’ success. In some cases, populations of predators and parasitoids are decimated, necessitating even greater use of insecticide because the ecological service they provided in controlling herbivores has been lost.
Even when pesticides are not widely used, monocultures often have difficulty support natural enemies in great enough numbers for them to diminish pest populations. A lack of diversity in the first trophic level is linked to low abundance in the third because alternative resources that are necessary for stable, large natural enemy populations are missing from the system. Natural enemy diets can be subsidized by increasing landscape diversity through companion planting, border crops, cover crops, intercropping, or tolerance of some weed growth. When nectar or other sugar-rich resources are provided, the natural enemy population thrives.
Biological control
Morphological plant characteristics and natural enemy success
Beyond domatia and nutritional rewards, other plant characteristics influence the colonization of plants by natural enemies. These can include the physical size, shape, density, maturity, colour, and texture of a given plant species. Specific plant features such as the hairiness or glossiness of vegetation can have mixed effects on different natural enemies. For example, trichomes decrease hunting efficiency of many natural enemies, as trichomes tend to slow or prevent movement due to the physical obstacles they present or the adhesive secretions they produce. However, sometimes the prey species may be more impeded than the predator. For example, when the whitefly prey of the parasitoid Encarsia formosa is slowed by plant hairs, the parasitoid can detect and parasitize a higher number of juvenile whiteflies.
Many predatory coccinelid beetles have a preference for the type of leaf surface they frequent. Presented with the opportunity to land on glossy or hairy Brassica oleracea foliage, the beetles prefer the glossy foliage as they are better able to cling to these leaves. Studies are evaluating the effect of various plant genotypes on natural enemies.
Volatile organic compounds
Two ways the release of volatile organic compounds (VOCs) may benefit plants are the deterrence of herbivores and the attraction of natural enemies. Synthetic products could replicate the distinct VOC profiles released by different plants; these products could be applied to plants suffering from pests that are targeted by the attracted natural enemy. This could cause natural enemies to enter crops that are occupied by pest populations that would otherwise likely remain undetected by the natural enemies.
The four elements that must be considered before manipulating VOCs are as follows: The VOCs must effectively aid the natural enemy in finding the prey; the pest must have natural enemies present; the fitness cost of potentially attracting more herbivores must be exceeded by attracting natural enemies; and the natural enemies must not be negatively affected by direct plant defenses that may be present.
Extrafloral nectaries
The level of domestication of cotton plants correlates to indirect defense investment in the form of extrafloral nectaries. Wild varieties produce higher volumes of nectar and attract a wider variety of natural enemies. Thus, the process of breeding new cotton varieties has overlooked natural resistance traits in the pursuit of high-yielding varieties that can be protected by pesticides. Plants bearing extrafloral nectaries have lower pest levels along with greater levels of natural enemies. These findings illustrate the potential benefits that could be gained through incorporating the desirable genetics of wild varieties into cultivated varieties.
Domatia
Certain tropical plants host colonies of ants in their hollow domatia and provide the ants with nutrition delivered from nectaries or food bodies. These ant colonies have become dependent on the host plants for their survival and therefore actively protect the plant; this protection can take the form of killing or warding off pests, weeds, and certain fungal pathogens. Chinese citrus farmers have capitalized on this mutualistic relationship for many years by incorporating artificial ant nests into their crops to suppress pests.
Parasitoids
Parasitoids have successfully been incorporated into biological pest control programs for many years. Plants can influence the effect of parasitoids on herbivores by releasing chemical cues that attract parasitoids and by providing food sources or domatia. Certain parasitoids may be dependent on this plant relationship. Therefore, in agricultural areas where parasitoid presence is desired, ensuring the crops being grown meet all of these requirements is likely to promote higher parasitoid populations and better pest control.
In a sugar beet crop, when only beets were grown, few aphids were parasitized. However, when collard crops were grown next to the sugar beets, parasitism of aphids increased. Collard crops release more VOCs than sugar beets. As a result, the companion collard plants attract more aphid parasitoids, which kill aphids in both the collard and the nearby sugar beets.
In a related study, ethylene and other compounds released by rice plants in response to brown planthopper feeding attracted a facultative parasitoid that parasitizes brown planthopper eggs.
In another study, the presence of plant extrafloral nectaries in cotton crops caused parasitoids to spend more time in the cotton and led to the parasitization of more moth larva than in cotton crops with no nectaries. Since the publication of this study, most farmers have switched to cotton varieties with nectaries. A separate study found that a naturalized cotton variety emitted seven times more VOCs than cultivated cotton varieties when experiencing feeding damage. It is unknown whether this generalizes to other crops; there are cases of other crops that do not show the same trend.
These findings reveal the specific variables a farmer can manipulate to influence parasitoid populations and illustrate the potential impact parasitoid habitat management can have on pest control. In the case of cotton and other similar high-VOC crop scenarios, there is interest in genetically engineering the chemical pathways of cultivated varieties to selectively produce the high VOC's that were observed in the naturalized varieties in order to attract greater natural enemy populations. This presents challenges but could produce promising pest control opportunities.
Insect pathogens
Entomopathogens are another group of organisms that are influenced by plants. The extent of the influence largely depends on the evolutionary history shared between the two and the pathogens' method of infection and survival duration outside of a host. Different insect host plants contain compounds that cause modulate insect mortality when certain entomopathogens are simultaneously injected. Increases in mortality of up to 50-fold have been recorded. However, certain plants influence entomopathogens in negative ways, reducing their efficacy.
It is primarily the leaf surface of the plant that influences the entomopathogen; plants can release various exudates, phytochemicals, and alleolochemicals through their leaves, some of which have the ability to inactivate certain entomopathogens. In contrast, in other plant species, leaf characteristics can increase the efficacy of entomopathogens. For example, the mortality of pea aphids was higher in the group of aphids that were found on plants with fewer wax exudates than in those on plants with more wax exudates. This reduced waxiness increases the transmission of Pandora neoaphidus conidia from the plant to the aphids.
Feeding-induced volatiles emitted by different plants increase the amount of spores released by certain entomopathogenic fungi, increasing the likelihood of infection of some herbivores but not others. Plants can also influence pathogen efficacy indirectly, and this typically occurs either by increasing the susceptibility of the herbivore hosts or by changing their behavior. This influence can often take the form of altered growth rates, herbivore physiology, or feeding habits. Thus, there are various ways that host plant species can influence entomopathogenic interactions.
In one study, brassicas were found to defend themselves by acting as a vector for entomopathogens. Virus-infected aphids feeding on the plants introduce a virus into the phloem. The virus is passively transported in the phloem and carried throughout the plant. This causes aphids feeding apart from the infected aphids to become infected as well. This finding offers the possibility of injecting crops with compatible entomopathogenic viruses to defend against susceptible insect pests.
Below-ground tritrophic interactions
Less studied than above-ground interactions, but proving to be increasingly important, are the below-ground interactions that influence plant defense. There is a complex network of signal transduction pathways involved in plant responses to stimuli, and soil microbes can influence these responses. Certain soil microbes aid plant growth, producing increased tolerance to various environmental stressors, and can protect their host plants from many different pathogens by inducing systemic resistance. Organisms in above- and below-ground environments can interact indirectly through plants. Many studies have shown both the positive and negative effects that one organism in one environment can have on other organisms in the same or opposite environment, with the plant acting as the intermediary.
The colonization of plant roots with mycorhizae typically results in a mutualistic relationship between the plant and the fungus, inducing a number of changes in the plant. Such colonization has a mixed impact on herbivores; insects with different feeding methods are affected differently, some positively and others negatively. The mycorhizal species involved also matters. One common species, Rhizophagus irregularis, has been observed to have a negative effect on the feeding success of chewing herbivores, whereas other species studied have positive effects.
The roots of some maize plants produce a defense chemical when roots are damaged by leaf beetle larvae; this chemical attracts the entomopathogenic nematode species Heterorhabditis megidis. Only certain maize varieties produce this chemical; plants that release the chemical see up to five times as much parasitization of leaf beetle larvae as those that do not. Incorporating these varieties or their genes into commercial maize production could increase the efficacy of nematode treatments.
Further studies suggest that the plant-emitted chemicals act as the primary source of attractant to the nematodes. Herbivores are believed to have evolved to evade detection on the part of the nematodes, whereas the plants have evolved to release highly attractive chemical signals. A high degree of specificity is involved; species that make up these tritrophic interactions have evolved with one another over a long period of time and as a result have close interrelationships.
Microorganisms can also influence tritrophic interactions. The bacterium Klebsiella aerogenes produces the volatile 2,3-butanediol, which modulates interactions between plants, pathogens, and insects. When maize plants are grown in a soil culture containing the bacterium or the plants are inoculated with the bacterium, the maize is more resistant to the fungus Setosphaeria turcica. The bacterium does not deter insect herbivory; it actually increases weight gain and leaf consumption in the caterpillar Spodoptera littoralis. However, the parasitic wasp Cotesia marginiventris is attracted more readily to maize plants grown in soil cultures containing either the volatile-producing bacterium or pure 2,3-butanediol.
Considerations in utilizing tritrophic interactions in biological control
Sustainable crop production is becoming increasingly important, if humans are to support a growing population and avoid a collapse of production systems. While the understanding and incorporation of tritrophic interactions in pest control offers a promising control option, the sustainable biological control of pests requires a dynamic approach that involves diversity in all of the species present, richness in natural enemies, and limited adverse activity (i.e., minimal pesticide use). This approach is especially important in conservation biological control efforts.
There are typically more than three trophic levels at play in a given production setting, so the tritrophic interaction model may represent an oversimplification. Furthermore, ecological complexity and interactions between species of the same trophic level can come into play. Research thus far has had a relatively narrow focus, which may be suitable for controlled environments such as greenhouses but which has not yet addressed multi-generational plant interactions with dynamic communities of organisms.
References
Antipredator adaptations
Herbivory
Biological pest control
Chemical ecology | Tritrophic interactions in plant defense | [
"Chemistry",
"Biology"
] | 4,409 | [
"Chemical ecology",
"Biological defense mechanisms",
"Herbivory",
"Antipredator adaptations",
"Biochemistry",
"Eating behaviors"
] |
42,730,228 | https://en.wikipedia.org/wiki/C%20Capricorni | c Capricorni can refer to two different stars:
c1 Capricorni or 46 Capricorni, commonly called simply c Capricorni.
c2 Capricorni or 47 Capricorni.
References
Capricornus
Capricorni, c | C Capricorni | [
"Astronomy"
] | 58 | [
"Capricornus",
"Constellations"
] |
42,730,692 | https://en.wikipedia.org/wiki/Christ%E2%80%93Kiselev%20maximal%20inequality | In mathematics, the Christ–Kiselev maximal inequality is a maximal inequality for filtrations, named for mathematicians Michael Christ and Alexander Kiselev.
Continuous filtrations
A continuous filtration of is a family of measurable sets such that
, , and for all (stratific)
(continuity)
For example, with measure that has no pure points and
is a continuous filtration.
Continuum version
Let and suppose is a bounded linear operator for finite . Define the Christ–Kiselev maximal function
where . Then is a bounded operator, and
Discrete version
Let , and suppose is a bounded linear operator for finite . Define, for ,
and . Then is a bounded operator.
Here, .
The discrete version can be proved from the continuum version through constructing .
Applications
The Christ–Kiselev maximal inequality has applications to the Fourier transform and convergence of Fourier series, as well as to the study of Schrödinger operators.
References
Mathematical analysis
Inequalities
Measure theory | Christ–Kiselev maximal inequality | [
"Mathematics"
] | 199 | [
"Mathematical analysis",
"Binary relations",
"Mathematical relations",
"Inequalities (mathematics)",
"Mathematical problems",
"Mathematical theorems"
] |
42,730,851 | https://en.wikipedia.org/wiki/Sexual%20practices%20between%20men | Sexual activities involving men who have sex with men (MSM), regardless of their sexual orientation or sexual identity, can include anal sex, non-penetrative sex, and oral sex. Evidence shows that sex between men is significantly underreported in surveys.
Behaviors
Various sex positions may be performed during sexual activity between men. Evidence shows that sex between men is significantly underreported in surveys due to social desirability bias.
Anal sex
Historically, anal sex has been popularly associated with male homosexuality. Many MSM, however, do not engage in anal sex, and may engage in oral sex, frottage or frot, and/or mutual masturbation instead.
Among men who have anal sex with other men, the partner who inserts his penis may be referred to as the top, the one being penetrated may be referred to as the bottom, and those who enjoy either role may be referred to as versatile. When MSM engage in anal sex without using a condom, this is referred to as bareback sex. Pleasure, pain, or both may accompany anal sex. While the nerve endings in the anus can provide pleasurable feelings, an orgasm may be achieved through receptive anal penetration by indirect stimulation of the prostate. A study by the National Survey of Sexual Health and Behavior (NSSHB) indicated that men who self-report taking a receptive position during anal sex in their last encounter were at least as likely to have reached orgasm as men who adopted an insertive role. A study sampling single people in the U.S. indicated that orgasm rates are similar among men across sexual orientations. With regard to pain or being uncomfortable during anal sex, some research indicates that, for 24% to 61% of gay or bisexual men, painful receptive anal sex (known as anodyspareunia) is a frequent lifetime sexual difficulty.
Reports pertaining to the prevalence of anal sex among MSM have varied over time, with some percentages higher than others. A large percentage of gay and bisexual men self-report lifetime participation in anal sex. Studies among gay men have indicated that percentages are similar when comparing men who prefer to penetrate their partners to those who prefer to be the receptive partner. Some men who have sex with men, however, believe that being a receptive partner during anal sex questions their masculinity.
Non-penetrative sex and masturbation
There are a variety of non-penetrative sex practices. Frot is a sexual activity between men that usually involves penis-to-penis contact. It is a form of frottage. Frot can be enjoyable because it mutually and simultaneously stimulates the genitals of both partners as it tends to produce pleasurable friction against the frenulum nerve bundle on the underside of each man's penile shaft, just below the urinary opening (meatus) of the penis head (glans penis). Intercrural sex is another form of non-penetrative sex that can be practiced between MSM. Docking (the insertion of one man's penis into another man's foreskin) is also practiced.
Manual sex is another non-penetrative sex act that can occur between men. This includes handjobs, which is the use of one's hands to stimulate someone else's penis or scrotum, and anal fingering, which is the use of one's fingers to stimulate someone's anus.
MSM may use sex toys. According to an online survey of 25,294 men who self-reported a homosexual or bisexual orientation, 49.8% have used vibrators. Most men who had used a vibrator in the past reported use during masturbation (86.2%). When used during partnered interactions, vibrators were incorporated into foreplay (65.9%) and intercourse (59.4%).
Oral sex
MSM may engage in oral sex, including fellatio, which is using the mouth to stimulate another person's penis or scrotum, and anilingus, which is stimulating someone else's anus using the tongue and lips. Wellings et al. reported that "the equation of 'homosexual' with 'anal' sex among men is common among lay and health professionals alike," whereas an online survey of 18,000 MSM in Europe "showed that oral sex was most commonly practised, followed by mutual masturbation, with anal intercourse in third place." A 2011 survey by The Journal of Sexual Medicine found similar results for U.S. gay and bisexual men. Kissing a partner on the mouth (74.5%), oral sex (72.7%), and partnered masturbation (68.4%) were the three most common behaviors, with 63.2% of the sample self-reporting five to nine different sexual behaviors during their last encounter.
Health risks
A variety of sexually transmitted infections (STIs) can result from sexual activity. A 2007 study reported that two large population surveys found "the majority of gay men had similar numbers of unprotected sexual partners annually as straight men and women."
Legality
Some or all sexual acts between men are currently or were formerly classified as crimes in jurisdictions of some countries. In its December 2020 report, International Lesbian, Gay, Bisexual, Trans and Intersex Association (ILGA) found that certain sexual acts between men are criminalized in 67 of 193 UN member states and one non-independent jurisdiction, the Cook Islands, while two UN member states, Iraq and Egypt, criminalize it de facto but not in legislation. In Egypt, there is no law against homosexuality but gay and bisexual men are prosecuted under other laws, most famously the Cairo 52. In at least six UN member states—Brunei, Iran, Mauritania, Nigeria (only northern Nigeria), Saudi Arabia and Yemen—it is punishable by death. In 2007, five countries executed someone as a penalty for homosexual acts. In 2020, ILGA named Iran and Saudi Arabia as the only countries in which executions for same-sex activity have reportedly taken place. In other countries, such as Yemen and Iraq, extrajudicial executions are carried out by militias such as Islamic State or Al-Qaeda. Many other countries had such laws in the past, but they were repealed, especially since 1945. Such laws are inherently difficult to enforce; more often than not, they are not commonly enforced.
See also
Gay pornography
Homosexuality
LGBTQ sex education
Outline of LGBTQ topics
Same-sex relationship
Sexual practices between women
Terminology of homosexuality
References
Bibliography
Steven Gregory Underwood(2003): Gay Men and Anal Eroticism Tops, Bottoms, and Versatiles. Harrington Park Press. 978-1-56023-375-6
Ahmady, Kameel Et al 2020: Forbidden Tale (A comprehensive study on lesbian, gay, bisexuals (LGB) in Iran). AP Lambert Academic Publishing, Germany.
External links
Male homosexuality
Sexual acts
Anal sex | Sexual practices between men | [
"Biology"
] | 1,426 | [
"Sexual acts",
"Behavior",
"Sexuality",
"Mating"
] |
42,732,027 | https://en.wikipedia.org/wiki/Transition%20metal%20dichalcogenide%20monolayers | Transition-metal dichalcogenide (TMD or TMDC) monolayers are atomically thin semiconductors of the type MX2, with M a transition-metal atom (Mo, W, etc.) and X a chalcogen atom (S, Se, or Te). One layer of M atoms is sandwiched between two layers of X atoms. They are part of the large family of so-called 2D materials, named so to emphasize their extraordinary thinness. For example, a MoS2 monolayer is only 6.5 Å thick. The key feature of these materials is the interaction of large atoms in the 2D structure as compared with first-row transition-metal dichalcogenides, e.g., WTe2 exhibits anomalous giant magnetoresistance and superconductivity.
The discovery of graphene shows how new physical properties emerge when a bulk crystal of macroscopic dimensions is thinned down to one atomic layer. Like graphite, TMD bulk crystals are formed of monolayers bound to each other by van-der-Waals attraction. TMD monolayers have properties that are distinctly different from those of the semimetal graphene:
TMD monolayers MoS2, WS2, MoSe2, WSe2, MoTe2 have a direct band gap, and can be used in electronics as transistors and in optics as emitters and detectors.
The TMD monolayer crystal structure has no inversion center, which allows to access a new degree of freedom of charge carriers, namely the k-valley index, and to open up a new field of physics: valleytronics
The strong spin–orbit coupling in TMD monolayers leads to a spin–orbit splitting of hundreds meV in the valence band and a few meV in the conduction band, which allows control of the electron spin by tuning the excitation laser photon energy and handedness.
2D nature and high spin–orbit coupling in TMD layers can be used as promising materials for spintronic applications.
The work on TMD monolayers is an emerging research and development field since the discovery of the direct bandgap and the potential applications in electronics and valley physics. TMDs are often combined with other 2D materials like graphene and hexagonal boron nitride to make van der Waals heterostructures. These heterostructures need to be optimized to be possibly used as building blocks for many different devices such as transistors, solar cells, LEDs, photodetectors, fuel cells, photocatalytic and sensing devices. Some of these devices are already used in everyday life and can become smaller, cheaper and more efficient by using TMD monolayers.
Crystal structure
Transition-metal dichalcogenides (TMDs) are composed of three atomic planes and often two atomic species: a metal and two chalcogens. The honeycomb, hexagonal lattice has threefold symmetry and can permit mirror plane symmetry and/or inversion symmetry. In the macroscopic bulk crystal, or more precisely, for an even number of monolayers, the crystal structure has an inversion center. In the case of a monolayer (or any odd number of layers), the crystal may or may not have an inversion center.
Broken inversion symmetry
Two important consequences of that are:
nonlinear optical phenomena, such as second-harmonic generation. When the crystal is excited by a laser, the output frequency can be doubled.
an electronic band structure with direct energy gaps, where both conduction and valence band edges are located at the non-equivalent K points (K+ and K−) of the 2D hexagonal Brillouin zone. The interband transitions in the vicinity of the K+ (or K−) point are coupled to right (or left) circular photon polarization states. These so-called valley dependent optical selection rules arise from inversion symmetry breaking. This provides a convenient method to address specific valley states (K+ or K−) by circularly polarized (right or left) optical excitation. In combination with strong spin-splitting, the spin and valley degree of freedom are coupled, enabling stable valley polarization.
These properties indicate that TMD monolayers represent a promising platform to explore spin and valley physics with the corresponding possible applications.
Properties
Transport properties
At submicron scales, 3D materials no longer have the same behavior as their 2D form, which can be an advantage. For example, graphene has a very high carrier mobility, and accompanying lower losses through the Joule effect. But graphene has zero bandgap, which results in a disqualifyingly low on/off ratio in transistor applications. TMD monolayers might be an alternative: they are structurally stable, display a band gap and show electron mobilities comparable to those of silicon, so they can be used to fabricate transistors.
Although thin-layer TMDs have been found to have a lower electron mobility than bulk TMDs, most likely because their thinness makes them more susceptible to damage, it has been found that coating the TMDs with HfO2 or hexagonal boron nitride (hBN) increases their effective carrier mobility.
Optical properties
A semiconductor can absorb photons with energy larger than or equal to its bandgap. This means that light with a shorter wavelength is absorbed. Semiconductors are typically efficient emitters if the minimum of the conduction band energy is at the same position in k-space as the maximum of the valence band, i.e., the band gap is direct. The band gap of bulk TMD material down to a thickness of two monolayers is still indirect, so the emission efficiency is lower compared to monolayered materials. The emission efficiency is about 104 greater for TMD monolayer than for bulk material. The band gaps of TMD monolayers are in the visible range (between 400 nm and 700 nm). The direct emission shows two excitonic transitions called A and B, separated by the spin–orbit coupling energy. The lowest energy and therefore most important in intensity is the A emission. Owing to their direct band gap, TMD monolayers are promising materials for optoelectronics applications.
Atomic layers of MoS2 have been used as a phototransistor and ultrasensitive detectors. Phototransistors are important devices: the first with a MoS2 monolayer active region shows a photoresponsivity of 7.5 mA W−1 which is similar to graphene devices that reach 6.1 mA W−1. Multilayer MoS2 show higher photoresponsivities, about 100 mA W−1, which is similar to silicon devices. Making a gold contact at the far edges of a monolayer allows an ultrasensitive detector to be fabricated. Such a detector has a photoresponsivity reaching , 106 greater than the first graphene photodetectors. This high degree of electrostatic control is due to the thin active region of the monolayer. Its simplicity and the fact that it has only one semiconductor region, whereas the current generation of photodetectors is typically a p–n junction, makes possible industrial applications such as high-sensitivity and flexible photodetectors. The only limitation for currently available devices is the slow photoresponse dynamics. Utilizing WSe2 the photoresponse was improved to a bandwidth of over 230 MHz by device symmetry optimization
Mechanical properties
Interest in the use of TMD monolayers such as MoS2, WS2, and WSe2 for the use in flexible electronics due to a change from an indirect band gap in 3D to a direct band gap in 2D emphasizes the importance of the mechanical properties of these materials. Unlike in bulk samples it is much more difficult to uniformly deform 2D monolayers of material and as a result, taking mechanical measurements of 2D systems is more challenging. A method that was developed to overcome this challenge, called atomic force microscopy (AFM) nanoindentation, involves bending a 2D monolayer suspended over a holey substrate with an AFM cantilever and measuring the applied force and displacement. Through this method, defect free mechanically exfoliated monolayer flakes of MoS2 were found to have a Young's modulus of 270 GPa with a maximum experienced strain of 10% before breaking. In the same study, it was found that bilayer mechanically exfoliated MoS2 flakes have a lower Young's modulus of 200 GPa, which is attributed to interlayer sliding and defects in the monolayer. With increasing flake thickness the bending rigidity of the flake plays a dominant role and it is found that the Young's modulus of multilayer, 5- 25 layers, mechanically exfoliated MoS2 flakes is 330 GPa.
The mechanical properties of other TMDs such as WS2 and WSe2 have also been determined. The Young's modulus of multilayer, 5-14 layers, mechanically exfoliated WSe2 is found to be 167 GPa with a maximum strain of 7%. For WS2, the Young's modulus of chemical vapor deposited monolayer flakes is 272 GPa. From this same study the Young's modulus of CVD-grown monolayer flakes of MoS2 is found to be 264 GPa. This is an interesting result as the Young's modulus of the exfoliated MoS2 flake is nearly the same as that of the CVD grown MoS2 flake. It is generally accepted that chemically vapor deposited TMDs will include more defects when compared with the mechanically exfoliated films that are obtained from bulk single crystals, which implies that defects (points defects, etc.) that are included in the flake do not drastically affect the strength of the flake itself.
Under the application of strain, a decrease in the direct and indirect band gap is measured that is approximately linear with strain. Importantly, the indirect bandgap decreases faster with applied strain to the monolayer than the direct bandgap, resulting in a crossover from direct to indirect band gap at a strain level of around 1%. As a result, the emission efficiency of monolayers is expected to decrease for highly strained samples. This property allows mechanical tuning of the electronic structure and also the possibility of fabrication of devices on flexible substrates.
Fabrication of TMD monolayers
Exfoliation
Exfoliation is a top down approach. In the bulk form, TMDs are crystals made of layers, which are coupled by Van-der-Waals forces. These interactions are weaker than the chemical bonds between the Mo and S in MoS2, for example. So TMD monolayers can be produced by micromechanical cleavage, just as graphene.
The crystal of TMD is rubbed against the surface of another material (any solid surface). In practice, adhesive tape is placed on the TMD bulk material and subsequently removed. The adhesive tape, with tiny TMD flakes coming off the bulk material, is brought down onto a substrate. On removing the adhesive tape from the substrate, TMD monolayer and multilayer flakes are deposited. This technique produces small samples of monolayer material, typically about 5–10 micrometers in diameter.
Large quantities of exfoliated material can also be produced using liquid-phase exfoliation by blending TMD materials with solvents and polymers.
Chemical vapor deposition
Chemical vapor deposition (CVD) is another approach used to synthesize transition-metal dichalcogenides. It has been used broadly to synthesize many different TMDs because it can be easily adapted for different TMD materials. Generally, CVD growth of TMDs is achieved by putting precursors to the material, typically a transition-metal oxide and pure chalcogen, into a furnace with the substrate on which the material will form. The furnace is heated to high temperatures (anywhere from 650 to 1000 °C) with an inert gas, typically N2 or Ar, flowing through the tube. Some materials require H2 gas as a catalyst for formation, so it may be flowed through the furnace in smaller quantities than the inert gas.
Outside of traditional CVD, metal organic chemical vapor deposition (MOCVD) has been used to synthesize TMDs. Unlike traditional CVD described above, MOCVD uses gaseous precursors, as opposed to solid precursors and MOCVD is usually carried out at lower temperatures, anywhere from 300 to 900 °C. MOCVD has been shown to provide more consistent wafer-scale growth than traditional CVD.
CVD is often used over mechanical exfoliation despite its added complexity because it can produce monolayers ranging anywhere from 5 to 100 microns in size as opposed to the surface areas of roughly 5-10 microns produced using the mechanical exfoliation method. Not only do TMD monolayers produced by CVD have a larger surface area than those flakes produced by mechanical exfoliation, they are often more uniform. Monolayer TMD flakes with very little or no multilayer areas can be produced by chemical vapor deposition, in contrast to samples produced by mechanical exfoliation, which often have many multilayered areas. An alternative method has demonstrated that transition metal sulfides, including those of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, can be synthesized through sulfurization of metal oxides in CS₂ vapor, achieving gram-scale production with simpler equipment and precursors. Geometrically confined-growth techniques are also recently applied to realize wafer-scale single-domain TMD monolayer arrays and their heterostructures.
Molecular-beam epitaxy
Molecular-beam epitaxy (MBE) is an established technique for growing semiconductor devices with atomic monolayer thickness control. MBE has been used to grow different TMDs, such as MoSe2, WSe2, and early transition metals, including titanium, vanadium, and chromium, tellurides, resulting in extremely clean samples with a thickness of only 0.5 monolayer.
The growth takes place in ultra-high vacuum (UHV). Precursors for the target materials are placed into evaporation cells, usually as powder (for example selenium), or as a rod (for example molybdenum). Some elements, such as selenium and tellurium, both of which are chalcogens, can be used in pure solid form as precursors. Some elements, however, can only be used when extracted from solid compounds, such as sulfur from FeS2. The compound materials are broken down by heating up the material at UHV pressures. The evaporation cells are either Knudsen cells or electron beam evaporation based, depending on the materials; electron beam evaporation works with rods and can be used to reach high temperatures without overheating heating filaments, while Knudsen cells are suitable for powders and materials with a lower evaporation point. The evaporated materials are then directed towards the substrate; some common ones are MoS2, HOPG, mica, or a sapphire substrate, such as Al2O3. A specific substrate is chosen to fit the targeted growth the best. The substrate is kept heated during the process to enhance the growth, with the temperatures ranging from 300 °C to 700 °C. The temperature of the substrate is one key factor of the growth, and altering it can be used to grow different phases, such as 1T and 2H, of the same material.
MBE holds some advantages in regards to both manual exfoliation and CVD. Use of reflection high-energy electron diffraction (RHEED) enables the in-situ monitoring of the growth, and this additionally with UHV and slow growth speed allows one to create clean, atomically thin monolayers. The improvement in sample quality is considerable when compared to exfoliation, as MBE is more effective in getting rid of the large flakes and impurities. In contrast to CVD, MBE proves beneficial when single-layerd TMDs are required. The disadvantage of MBE is that it is a relatively complicated process that requires large amounts of specialized equipment. Maintaining UHV can be difficult, and the preparation of samples is slower than in the other two methods.
Electrochemical Deposition
Electrodeposition is among the techniques that have emerged to produce TMDC semiconductors such as MoS2, WS2 and WSe2. Several reports have shown controlled electrodeposition of TMDC layers down to a monolayer. The materials have so far shown continuous films of good uniformity but typically require annealing temperatures > 500 °C. Electrodepositions of TMDC films have been successfully reported over conducting films such as graphene and TiN, and over a SiO2 insulator by growing the TMDC laterally starting from a conductive film.
Electronic band structure
Band gap
In the bulk form, TMD have an indirect gap in the center of the Brillouin zone, whereas in monolayer form the gap becomes direct and is located in the K points.
Spin–orbit coupling
For TMDs, the atoms are heavy and the outer layers electronic states are from d-orbitals that have a strong spin–orbit coupling. This spin orbit coupling removes the spins degeneracy in both the conduction and valence band i.e. introduces a strong energy splitting between spin up and down states. In the case of MoS2, the spin splitting in conduction band is in the meV range, it is expected to be more pronounced in other material like WS2. The spin orbit splitting in the valence band is several hundred meV.
Spin-valley coupling and the electron valley degree of freedom
By controlling the charge or spin degree of freedom of carriers, as proposed by spintronics, novel devices have already been made. If there are different conduction/valence band extrema in the electronic band structure in k-space, the carrier can be confined in one of these valleys. This degree of freedom opens up a new field of physics: the controlling of carriers k-valley index, also called valleytronics.
For TMD monolayers crystals, the parity symmetry is broken, there is no more inversion center. K valleys of different directions in the 2D hexagonal Brillouin zone are no longer equivalent. So there are two kinds of K valley called K+ and K−. Also there is a strong energy degeneracy of different spin states in valence band. The transformation of one valley to another is described by the time reversal operator. Moreover, crystal symmetry leads to valley dependent optical selection rules: a right circular polarized photon (σ+) initializes a carrier in the K+ valley and a left circular polarized photon (σ-) initializes a carrier in the K− valley. Thanks to these two properties (spin-valley coupling and optical selection rules), a laser of specific polarization and energy allows to initialize the electron valley states (K+ or K−) and spin states (up or down).
Emission and absorption of light: excitons
A single layer of TMD can absorb up to 20% of incident light, which is unprecedented for such a thin material. When a photon of suitable energy is absorbed by a TMD monolayer, an electron is created in the conduction band; the electron now missing in the valence band is assimilated by a positively charged quasi-particle called a hole. The negatively charged electron and the positively charged hole are attracted via the Coulomb interaction, forming a bound state called an exciton which can be thought as a hydrogen atom (with some difference). This Bosonic-like quasi-particle is very well known and studied in traditional semiconductors, such as GaAs and ZnO but in TMD it provides exciting new opportunities for applications and for studying fundamental physics. Indeed, the reduced dielectric screening and the quantum size effect present in these ultrathin materials make the binding energy of excitons much stronger than those in traditional semiconductors. Binding energies of several hundreds of meV are observed for all the four principal members of the TMD family.
As mentioned before, we can think about an exciton as if it were a hydrogen atom, with an electron bound to a hole. The main difference is that this system is not stable and tends to relax to the vacuum state, which is here represented by an electron in the valence band. The energy difference between the exciton 'ground state' (n=1) and the 'vacuum state' is called optical gap and is the energy of the photon emitted when an exciton recombines. This is the energy of the photons emitted by TMD monolayers and observed as huge emission peaks in photoluminescence (PL) experiments, such as the one labelled X0 in the figure. In this picture the binding energy EB is defined as the difference between the free particle band gap and the optical band gap and represent, as usual, the energy needed to take the hole and the electron apart. The existence of this energy difference is called band gap renormalization. The analogy with hydrogen atom doesn't stop here as excitonic excited states were observed at higher energies and with different techniques.
Because of the spin–orbit splitting of the valence band two different series of excitons exist in TMD, called A- and B-excitons. In the A series the hole is located in the upper branch of the Valence band while for the B-exciton the hole is in the lower branch. As a consequence the optical gap for B-exciton is larger and the corresponding peak is found at higher energy in PL and reflectivity measurements.
Another peak usually appears in the PL spectra of TMD monolayers, which is associated to different quasi-particles called trions. These are excitons bound to another free carrier which can be either an electron or a hole. As a consequence a trion is a negative or positively charged complex. The presence of a strong trion peak in a PL spectrum, eventually stronger than the peak associated with exciton recombination, is a signature of a doped monolayer. It is believed now that this doping is extrinsic, which means that it arises from charged trap states present in the substrate (generally SiO2). Positioning a TMD monolayer between two flakes of hBN removes this extrinsic doping and greatly increase the optical quality of the sample.
At higher excitation powers biexcitons have also been observed in monolayer TMDs. These complexes are formed by two bound excitons. Theory predicts that even larger charge-carrier complexes, such as charged biexcitons (quintons) and ion-bound biexcitons, are stable and should be visible in the PL spectra. Additionally, quantum light has been observed to originate from point defects in these materials in a variety of configurations.
Radiation effects of TMD monolayers
Common forms of radiation used to create defects in TMDs are particle and electromagnetic irradiation, impacting the structure and electronic performance of these materials. Scientist have been studying the radiation response of these materials to be used in high-radiation environments, such as space or nuclear reactors. Damage to this unique class of materials occurs mainly through sputtering and displacement for metals or radiolysis and charging for insulators and semiconductors. To sputter away an atom, the electron must be able to transfer enough energy to overcome the threshold for knock-on damage. Yet, the exact quantifiable determination of this energy still needs to be determined for TMDs. Consider MoS2 as an example, TEM exposure via sputtering creates vacancies in the lattice, these vacancies are then observed to be collected together in spectroscopic lines. Additionally, when looking at the radiation response of these materials, the three parameters that are proven to matter most are the choice of substrate, the sample thickness, and the sample preparation process.
Janus TMD monolayers
A new type of asymmetric transitional metal dichalcogenide, the Janus TMDs monolayers, has been synthesized by breaking the out-of-plane structural symmetry via plasma assisted chemical vapor deposition. Janus TMDs monolayers show an asymmetric structure MXY (M = Mo or W, X/Y = S, Se or Te) exhibiting out-of-plane optical dipole and piezoelectricity due to the imbalance of the electronic wave-function between the dichalcogenides, which are absent in a non-polar TMDs monolayer, MX2. In addition, the asymmetric structure of Janus MoSSe provides an enhanced Rashba spin–orbit interaction, which suggests asymmetrically Janus TMDs monolayer can be a promising candidate for spintronic applications. In addition, Janus TMDs monolayer has been considered as an excellent material for electrocatalysis or photocatalysis.
Janus MoSSe can be synthesized by inductively coupled plasma CVD (ICP-CVD). The top layer of sulfur atoms on MoS2 is stripped using hydrogen ions, forming an intermediate state, MoSH. Afterward, the intermediate state is selenized by thermal annealing at 250 °C in an environment of hydrogen and argon gases.
Aspirational uses
Electronics
A field-effect transistor (FET) made of monolayer MoS2 showed an on/off ratio exceeding 108 at room temperature owing to electrostatic control over the conduction in the 2D channel. FETs made from MoS2, MoSe2, WS2, and WSe2 have been made. All show promise not just because of their electron mobility and band gap, but because their very thin structure makes them promising for use in thin, flexible electronics.
Sensing
The band gap TMDs possess makes them attractive for sensors as a replacement for graphene. FET-based biosensors rely on receptors attached to the monolayer TMD. When target molecules attach to the receptors, it affects the current flowing through the transistor.
However, it has been shown that one can detect nitrogenous bases in DNA when they pass through nanopores made in MoS2. Nanopore sensors are based upon measuring ionic current through a nanopore in a material. When a single strand of DNA passes through the pore, there is a marked decrease in ionic current for each base. By measuring the current flowing through the nanopore, the DNA can then be sequenced.
To this date, most sensors have been created from MoS2, although WS2 has been explored as well.
Specific examples
Molybdenum disulfide
Molybdenum disulfide monolayers consist of a unit of one layer of molybdenum atoms covalently bonded to two layers of sulfur atoms. While bulk molybdenum sulfide exists as 1T, 2H, or 3R polymorphs, molybdenum disulfide monolayers are found only in the 1T or 2H form. The 2H form adopts a trigonal prismatic geometry while the 1T form adopts an octahedral or trigonal antiprismatic geometry. Molybdenum monolayers can also be stacked due to Van der Waals interactions between each layer.
Electrical
The electrical properties of molybdenum sulfide in electrical devices depends on factors such as the number of layers, the synthesis method, the nature of the substrate on which the monolayers are placed on, and mechanical strain.
As the number of layers decrease, the band gap begins to increase from 1.2eV in the bulk material up to a value of 1.9eV for a monolayer. Odd number of molybdenum sulfide layers also produce different electrical properties than even numbers of molybdenum sulfide layers due to cyclic stretching and releasing present in the odd number of layers. Molybdenum sulfide is a p-type material, but it shows ambipolar behavior when molybdenum sulfide monolayers that were 15 nm thick were used in transistors. However, most electrical devices containing molybdenum sulfide monolayers tend to show n-type behavior.
The band gap of molybdenum disulfide monolayers can also be adjusted by applying mechanical strain or an electrical field. Increasing mechanical strain shifts the phonon modes of the molybdenum sulfide layers. This results in a decrease of the band gap and metal-to-insulator transition. Applying an electric field of 2-3Vnm−1 also decreases the indirect bandgap of molybdenum sulfide bilayers to zero.
Solution phase lithium intercalation and exfoliation of bulk molybdenum sulfide produces molybdenum sulfide layers with metallic and semiconducting character due to the distribution of 1T and 2H geometries within the material. This is due to the two forms of molybdenum sulfide monolayers having different electrical properties. The 1T polymorph of molybdenum sulfide is metallic in character while the 2H form is more semiconducting. However, molybdenum disulfide layers produced by electrochemical lithium intercalation are predominantly 1T and thus metallic in character as there is no conversion to the 2H form from the 1T form.
Thermal
The thermal conductivity of molybdenum disulfide monolayers at room temperature is 34.5W/mK while the thermal conductivity of few-layer molybdenum disulfide is 52W/mK. The thermal conductivity of graphene, on the other hand, is 5300W/mK. Due to the rather low thermal conductivity of molybdenum disulfide nanomaterials, it is not as promising material for high thermal applications as some other 2D materials.
Synthesis
Exfoliation
Exfoliation techniques for the isolating of molybdenum disulfide monolayers include mechanical exfoliation, solvent assisted exfoliation, and chemical exfoliation.
Solvent assisted exfoliation is done by sonicating bulk molybdenum disulfide in an organic solvent such as isopropanol and N-methyl-2-pyrrolidone, which disperses the bulk material into nanosheets as the Van der Waals interactions between the layers in the bulk material are broken. The amount of nanosheets produced is controlled by the sonication time, the solvent-molybdenum disulfide interactions, and the centrifuge speed. Compared to other exfoliation techniques, solvent assisted exfoliation is the simplest method for large scale production of molybdenum disulfide nanosheets.
The micromechanical exfoliation of molybdenum disulfide was inspired by the same technique used in the isolation of graphene nanosheets. Micromechanical exfoliation allows for low defect molybdenum disulfide nanosheets but is not suitable for large scale production due to low yield.
Chemical exfoliation involves functionalizing molybdenum difsulfide and then sonicating to disperse the nanosheets. The most notable chemical exfoliation technique is lithium intercalation in which lithium is intercalated into bulk molybdenum disulfide and then dispersed into nanosheets by the addition of water.
Chemical vapor deposition
Chemical vapor deposition of molybdenum disulfide nanosheets involves reacting molybdenum and sulfur precursors on a substrate at high temperatures. This technique is often used in the preparing electrical devices with molybdenum disulfide components because the nanosheets are applied directly on the substrate; unfavorable interactions between the substrate and the nanosheets that would have occurred had they been separately synthesized are decreased. In addition, since the thickness and area of the molybdenum disulfide nanosheets can be controlled by the selection of specific precursors, the electrical properties of the nanosheets can be tuned.
Electroplating
Among the techniques that have been used to deposit molybdenum disulfide is electroplating. Ultra-thin films consisting of few-layers have been produced via this technique over graphene electrodes. In addition, other electrode materials were also electroplated with MoS2, such as Titanium Nitride (TiN), glassy carbon and polytetrafluoroethylene. The advantage that this technique offers in producing 2D materials is its spatial growth selectivity and its ability to deposit over 3D surfaces. Controlling the thickness of electrodeposited materials can be achieved by adjusting the deposition time or current.
Laser ablation
Pulsed laser deposition involves the thinning of bulk molybdenum disulfide by laser to produce single or multi-layer molybdenum disulfide nanosheets. This allows for synthesis of molybdenum disulfide nanosheets with a defined shape and size. The quality of the nanosheets are determined by the energy of the laser and the irradation angle.
Lasers can also be used to form molybdenum disulfide nanosheets from molybdenum disulfide fullerene-like molecules.
Hafnium disulfide
Hafnium disulfide () has a layered structure with strong covalent bonding between the Hf and S atoms in a layer and weak van der Waals forces between layers. The compound has type structure and is an indirect band gap semiconducting material. The interlayer spacing between the layers is 0.56 nm, which is small compared to group VIB TMDs like , making it difficult to cleave its atomic layers. However, recently its crystals with large interlayer spacing has grown using a chemical vapor transport route. These crystals exfoliate in solvents like N-Cyclohexyl-2-pyrrolidone (CHP) in a time of just some minutes resulting in a high-yield production of its few-layers resulting in increase of its indirect bandgap from 0.9 eV to 1.3 eV. As an application in electronics, its field-effect transistors has been realised using its few layers as a conducting channel material offering a high current modulation ratio larger than 10000 at room temperature. Therefore, group IVB TMDs also holds potential applications in the field of opto-electronics.
Tungsten diselenide
Tungsten diselenide is an inorganic compound with the formula . The compound adopts a hexagonal crystalline structure similar to molybdenum disulfide. Every tungsten atom is covalently bonded to six selenium ligands in a trigonal prismatic coordination sphere, while each selenium is bonded to three tungsten atoms in a pyramidal geometry. The tungsten – selenium bond has a bond distance of 2.526 Å and the distance between selenium atoms is 3.34 Å. Layers stack together via van der Waals interactions. is a stable semiconductor in the group-VI transition-metal dichalcogenides. The electronic bandgap of can be tuned by mechanical strain which can also allow for conversion of the band type from indirect-to-direct in a bilayer.
References
External links
Semiconductor analysis
Transition metal dichalcogenides
Monolayers | Transition metal dichalcogenide monolayers | [
"Physics"
] | 7,410 | [
"Monolayers",
"Atoms",
"Matter"
] |
42,732,173 | https://en.wikipedia.org/wiki/Ibtesam%20Badhrees | Ibtesam Saeed Badhrees is a research scientist in experimental particle physics at King Abdulaziz City for Science and Technology (KACST) and a Distinguished Fellow of New Westminster College.
Badhrees is the first Saudi woman member of CERN. In addition, she is the first Saudi female PhD holder to work in the National Center for Mathematics and Physics in King Abdulaziz City for Science and Technology. Her research areas are in Experimental Elementary Particle Physics, Astrophysics, Medical Physics and Nuclear Physics. In addition, Badhrees acts as an adjunct professor at Carleton University in Canada
Biography
Ibtesam Badhrees was born and brought up in Jeddah, Saudi Arabia. She graduated with a Bachelor of Science in Physics from King Abdulaziz University in 1990 and then earned a Master of Science in Applied Physics/Laser from Fairleigh Dickinson University in 1997. She finished her PhD in Particle Physics from University of Bern in 2011. She also holds a PhD, in International Relations, from the Geneva School of Diplomacy and International Relations. She was the recipient of the Saudi Cultural Mission academic excellence award in 1996, 1997, 2007 and was named the "Woman Physicist of the Month" for August 2014 by the American Physical Society. She speaks Arabic, English and French.
Awards and recognition
Saudi Arabian Cultural Mission Academic Excellence Award, United States, 1996–1997.
Saudi Arabian Cultural Mission Academic Excellence Award, Europe, 2007.
CERN, as the first Saudi woman join the organization as a user researcher.
Alsharaq Alawsat Journal, 2008.
Saiduty Magazine, 2008.
MBC, Saudi Arabia, Egypt, 2008.
MBC, Saudi Arabia, Lebanon, 2009.
Madame Figaro, 2009.
Laha Magazine, As one of distinctive women in Saudi Arabia, 2013.
See also
Timeline of women in science
Women in physics
References
Living people
People associated with CERN
Fairleigh Dickinson University alumni
Fairleigh Dickinson University faculty
King Abdulaziz University alumni
Saudi Arabian women physicists
Saudi Arabian academics
University of Bern alumni
21st-century Saudi Arabian women scientists
21st-century Saudi Arabian scientists
Saudi Arabian women academics
Particle physicists
Year of birth missing (living people) | Ibtesam Badhrees | [
"Physics"
] | 434 | [
"Particle physicists",
"Particle physics"
] |
42,732,399 | https://en.wikipedia.org/wiki/Thermal%20history%20coating | A thermal history coating (THC) is a robust coating containing various non-toxic chemical compounds whose crystal structures irreversibly change at high temperatures. This allows for temperature measurements and thermal analysis to be performed on intricate and inaccessible components, which operate in harsh environments. Like thermal barrier coatings, THCs provide protection from intense heat to the surfaces on which they are applied. The temperature range that THCs provide accurate temperature measurements in is 900 °C to 1400 °C with an accuracy of ±10 °C.
Application of THCs
THCs are applied by atmospheric plasma spraying, which is a thermal spraying technique. This ensures that the coatings are robust to allow long life-times in harsh environments, such as on jet engine components, which experience temperatures in excess of 1000 °C and angular velocities of up to 10,000rpm (revolutions per minute).
Temperature Measurement
Phosphorescent Properties
THCs are composed of phosphor materials, whose luminescent characteristics are temperature- and duration-dependent. Phosphor thermometry is the measurement technique used for determining the past temperatures of THCs, whereby the luminescent characteristics of the coatings are exploited and matched to calibration tables.
Instrumentation
The phosphorescence of THCs is excited by use of an external light source such as a laser pen. An optical system then collects a reflected light signal, whose characteristics provide information on the crystal structure of the THC. Crystal structure properties are then converted into temperatures, which had previously been experience by the coatings. This allows for point measurements to be made across the coated surfaces of components and allows thermal analysis to be carried out.
Applications
R&D
THCs are used in high temperature applications where temperature knowledge is essential in research and development programmes, for example in identifying hot spots, which could lead to structural damage of components.
Warranty
As the THCs provide historic temperature information, they can be used as warranty tools, where certain components, such as valves or particular engine or machinery components must not exceed certain temperatures.
Other High-Temperature Detection Technologies
Thermocouple
Thermocrystal
Pyrometer
References
Materials science
Thermal protection | Thermal history coating | [
"Physics",
"Materials_science",
"Engineering"
] | 441 | [
"Applied and interdisciplinary physics",
"Materials science",
"nan"
] |
42,732,578 | https://en.wikipedia.org/wiki/Defensive%20expenditures | In environmental accounting, defensive expenditures are expenditures that seek to minimise potential damage to oneself. Examples include defence and insurance.
References
Risk management
Actuarial science
Environmental economics
Expenditure | Defensive expenditures | [
"Mathematics",
"Environmental_science"
] | 36 | [
"Applied mathematics",
"Actuarial science",
"Environmental social science",
"Environmental economics"
] |
42,732,702 | https://en.wikipedia.org/wiki/Primodos | Primodos was a hormone-based pregnancy test, produced by Schering AG, and used in the 1960s and 1970s that consisted of two pills that contained norethisterone (as acetate) and ethinylestradiol. It detected pregnancy by inducing menstruation in women who were not pregnant. The presence or absence of menstrual bleeding was then used to determine whether the user was pregnant. In South Korea it was also used, "perhaps as a double dose" to induce abortions.
While first made available for sale in the UK in 1959, it was withdrawn from sale in the UK in 1978.
Primodos was produced by Schering AG, a German company taken over by Bayer AG in 2006.
Another hormonal pregnancy test called Duogynon was in use in Germany during the same general time period.
History
In the 1960s, Dr. Isabel Gal conducted research at Queen Mary's Hospital for Children that showed a link between use of the drug and severe birth defects. A review by the Committee on Safety of Medicines in the 1970s concluded that the product should not be used by pregnant women. Litigation in the 1980s regarding these claims ended inconclusively, with proceedings being discontinued, with the court's approval. A review of the matter by the Medicines and Healthcare products Regulatory Agency in 2014 assessed the studies performed to date, and concluded that it found the evidence for adverse effects to be inconclusive.
The report of an expert working group of the UK Commission on Human Medicines published in November 2017 concluded there was no "causal association" between Primodos and severe disabilities in babies. The expert group recommended that families who took a hormone pregnancy test and experienced "an adverse pregnancy outcome" should be offered genetic testing to establish whether there was a different underlying cause.
Independent Medicines and Medical Devices Safety Review
An independent review by Baroness Cumberlege, the Independent Medicines and Medical Devices Safety Review, reported in 2020 that "avoidable harm" resulted from the use of Primodos. It recommended that "the Government should immediately issue a fulsome apology on behalf of the healthcare system to the families affected by Primodos".
Dr Bill Inman, of the Committee on Safety of Medicines, who had investigated Primodos was referenced in a Schering memo stating "he has destroyed all the material on which his investigation is based, or made it unrecognizable, which makes it impossible to trace the individual cases taken into the investigation. I understood Dr. Inman that he did this to prevent individual claims from using this material."
Baroness Cumberlege said, in relation to Bayer, "I think they should not only apologise; they should recognise what has happened and give ex-gratia payments to these people who have suffered."
References
Further reading
Tests for pregnancy
Drugs with unknown mechanisms of action
Drug safety
German inventions
20th-century health disasters
Health disasters in the United Kingdom
Medical controversies
Medical scandals
Withdrawn drugs
History of disability
Abortifacients | Primodos | [
"Chemistry"
] | 611 | [
"Drug safety",
"Withdrawn drugs"
] |
42,733,501 | https://en.wikipedia.org/wiki/Association%20for%20Logic%20Programming | The Association for Logic Programming (ALP) was founded in 1986. Its mission is "to contribute to the development of Logic Programming, relate it to other formal and also to humanistic sciences, and to promote its uses in academia and industry all over the world". It manages the International Conference on Logic Programming, oversees the journal Theory and Practice of Logic Programming (TPLP), and publishes an electronic newsletter.
The activities of the Association are directed by an Executive Committee and President, elected by ALP members. The current president is Enrico Pontelli. Here is a list of all presidents:
2024- Enrico Pontelli at New Mexico State University
2019-2024 Thomas Eiter (pro term 2019-2020) at Vienna University of Technology
2014-2019 Torsten Schaub at the University of Potsdam
2010-2014 Gopal Gupta at the University of Texas, Dallas
2005-2009 Manuel Hermenegildo at the Technical University of Madrid
2001-2004 Veronica Dahl at Simon Fraser University
1997-2000 Krzysztof R. Apt at Centrum Wiskunde & Informatica in Amsterdam
1993-1996 David Scott Warren at Stony Brook
1989-1992 Herve' Gallaire at the European Computer-Industry Research Center in Munich
1986-1988 Keith Clark at Imperial College London
In 1997, the ALP bestowed to fifteen recognized researchers in logic programming the title Founders of Logic Programming to recognize them as pioneers in the field.
The ALP Alain Colmerauer Prize
The ALP Alain Colmerauer Prolog Heritage Prize (in short: the Alain Colmerauer Prize) is organized by the ALP. The Prize is given for recent accomplishments and practical advances in Prolog-inspired computing, understood in a broad sense, where foundational, technological, and practical contributions are eligible with proven evidence or potential for the future development of Logic Programming.
References
External links
Association for Logic Programming (ALP)
Theory and Practice of Logic Programming journal
Computer science organizations
Organizations established in 1986
Computer science-related professional associations | Association for Logic Programming | [
"Technology"
] | 406 | [
"Computer science",
"Computer science organizations"
] |
42,734,050 | https://en.wikipedia.org/wiki/Complex%20Projects%20Contract | The CIOB Complex Projects Contract 2013 was a form of construction and engineering contract, developed by the Chartered Institute of Building (CIOB). Its formal name was the 'Contract for Use with Complex Projects, First Edition 2013'.
In November 2015, the Complex Projects Contract was updated by the Chartered Institute of Building in response to feedback from the industry. Despite effectively being a second edition, it was renamed the Time and Cost Management Contract 2015 (abbreviated to TCM15) to reflect the core strengths of the contract.
Launch
Based upon extensive research carried out by the CIOB, the contract was formally launched on 23 April 2013. The contract was billed as the world's first contract specifically aimed at the management of time in complex construction and engineering projects. The authors also stated that it was the first form to follow the Society of Construction Law Delay and Disruption Protocol, and that it was also the first standard form contract to cater for Building Information Modelling (BIM) and the future of collaborative design.
Purpose
It is suited for works of high value or complexity, major real estate projects and engineering or infrastructure projects. It is not suited to simpler works, those of short duration or with inexperienced clients /contractors. It anticipates Special Conditions for the particular requirements of each project and if using construction management as the procurement method, it cannot be used without the appropriate terms being included in the Special Conditions.
CPC2013 is designed for use by companies and public authorities in the UK and in any other country where works comprise complex building and / or engineering, which cannot reasonably be expected to be managed intuitively. It can be used where the contractor is expected to construct only that designed by or under the direction of the client with traditional drawings, specification and/or bills of quantities, or BIM, or on projects which require a contractor's design in part, or for design-build projects in which the contractor designs the whole of the works with or without an employer's reference design.
The contract requires a collaborative approach to the management of design, quality, time and cost. The working schedule, planning method statement and progress records (which are to be inspected and accepted by a competent project time manager and independently audited for quality assurance) are at the core of management. They are the tools by which all time and time-related cost issues are to be determined and are to conform with the standards required by the conditions, appendices and the CIOB's Guide to Good Practice in the Management of Time in Complex Projects.
Collaboration
In order to promote collaboration and to ensure transparency of data, schedule and database submittals are to be made in native file format either by maintenance of the material in a common data environment or transfer by a file transfer protocol to all having a continuing design, administrative, or supervisory role, who are identified as Listed Persons. The contract also requires the appointment of a Contract Administrator to carry out administrative functions during the course of construction, a Project Time Manager to advise on time related matters, a Valuer to advise on cost matters, a Design Coordination Manager to manage the integration of the Contractor's design, and a Data Security Manager to supervise and maintain the integrity and security of digital communications.
Risk management
Central to the philosophy of the Complex Projects Contract is its approach to transparency in risk management. CPC2013 provides for both the owner and contractor each to identify one or more time contingency allowance, which each can use as it wishes to manage its own risks. Unusually for a standard form construction contract, it defines "float" and provides that if either party creates free float or total float as a result of its own improvement of progress, that party may keep the created float as its own contingency. Additional powers are provided in CPC2013 to enable the construction project's developer, following consultation, to instruct acceleration, recovery and changes in resources sequences and logic in order to manage its risks contemporaneously.
Time management
CPC2013 is distinctive in taking a prescriptive approach to the management of time and associated cost risk and combining critical path network techniques with resource-based planning. The time model, referred to as the Working Schedule, combines a high-density, short-term look-ahead similar in concept to that used in agile software development with medium and long-term lower density schedule along the lines of that used in the waterfall model planning technique, the whole being revised regularly on the Rolling Wave planning principle. In the short-term look-ahead, the logic is to be resource and location-related, instead of activity based, as it is in waterfall. The agile part of the schedule is to have its activity durations calculated by reference to the resources to be applied and their expected productivity.
Cost management
The activities in the Working Schedule are also to be valued so that the Working Schedule also functions as the pricing schedule to predict current value for the purposes of interim payment and the ultimate out-turn cost for cost risk management purposes.
Progress records
Progress is required to be recorded in a database identifying, at specified intervals, the resources used, productivity achieved and earned value. Apart from being the source data for subsequent progress update of the schedule, the database also serves for benchmarking productivity achievable for quality assurance of the schedule and future planning.
Dispute resolution
The emphasis of CPC2013 is on contemporaneous Issue Resolution by an appropriate expert. CPC2013 it also provides for an escalating Dispute Resolution procedure, embracing negotiation, mediation, adjudication and arbitration. Where issues are required to be determined by Issue Resolution within a certain timescale, if the procedure is not invoked there are deeming provisions which determine the outcome of an issue. If Dispute Resolution is required, the expert, adjudicator or arbitrator are either those named in the contract or, in default, they are appointed by the Academy of Experts in London or the CIOB. The default adjudication rules are those of the Scheme for Construction Contracts and the default arbitration procedure is that of the London Court of International Arbitration.
Ancillary publications
A back-to-back Consultancy Appointment and Subcontract, both of which followed the same principles of time and cost risk management, were published in November 2015 as part of the Time and Cost Management Contract 2015 suite.
Industry reception
A number of reviews and commentaries have been written on the subject of the Complex Projects Contract. Some have criticized the complexity of the contract itself .
whereas others have noted the benefits of the clear language, and have commented on the incorporation of its positive features. Reviews published have consistently commented that it will be necessary for the contract to be tested on a live project before the effectiveness can be proven.
External links
CIOB Time Management's website
CIOB Time and Cost Management Contract 2015's website
References
Construction | Complex Projects Contract | [
"Engineering"
] | 1,372 | [
"Construction"
] |
42,734,157 | https://en.wikipedia.org/wiki/CoCalc | CoCalc (formerly called SageMathCloud) is a web-based cloud computing (SaaS) and course management platform for computational mathematics. It supports editing of Sage worksheets, LaTeX documents and Jupyter notebooks. CoCalc runs an Ubuntu Linux environment that can be interacted with through a terminal, additionally giving access to most of the capabilities of Linux.
CoCalc offers both free and paid accounts. Subscriptions starting at $14/month provide internet access and more storage and computing resources. One subscription can be used to increase quotas for one project used by multiple accounts. There are subscription plans for courses. Over 200 courses have used CoCalc.
Features
CoCalc directly supports Sage worksheets, which interactively evaluate Sage code. The worksheets support Markdown and HTML for decoration, and R, Octave, Cython, Julia and others for programming in addition to Sage. CoCalc supports Jupyter notebooks, which are enhanced with real-time synchronization for collaboration and a history recording function. Additionally, there is also a full LaTeX editor, with collaboration support, a preview of the resulting document and also support for SageTeX. With its online Linux terminal, CoCalc also indirectly supports editing and running many other languages, including Java, C/C++, Perl, Ruby, and other popular languages that can be run on Linux. Other packages can be installed on request.
Users can have multiple projects on CoCalc, and each project has separate disk space and may be on an entirely different server. Many users can collaborate on a single project, and documents are synced, so multiple users can edit the same file at once, similar to Google Docs. All the data on projects is automatically backed up about every five minutes with bup, and snapshots of previous versions are accessible. Through the terminal, files can be tracked using revision control systems like Git.
Development
CoCalc operated by SageMath Inc. The creator and lead developer of CoCalc is William Stein, a former professor of mathematics at the University of Washington who also created the Sage software system. Initial development was funded by the University of Washington and grants from the National Science Foundation and Google. Now CoCalc is mostly funded by paying users. It is intended as a replacement for sagenb, which also let users edit and share Sage worksheets online.
References
External links
CoCalc homepage
CoCalc documentation
CoCalc FAQ
Google Chrome extension
Source code used for running CoCalc
Collaborative real-time editors
Free mathematics software
Free software programmed in Python
Free software websites
Mathematical software | CoCalc | [
"Mathematics",
"Technology"
] | 531 | [
"Computing websites",
"Free software websites",
"Free mathematics software",
"Collaborative real-time editors",
"Mathematical software"
] |
42,734,486 | https://en.wikipedia.org/wiki/Insect%20euthanasia | Insect euthanasia is the process of killing insects "in a way that minimizes or eliminates pain and distress." It may apply to animals in the laboratory, schools, as pets, as food, or otherwise.
Euthanasia of insects and other invertebrates has historically received limited attention. While vertebrate animal experimentation typically requires approval by an Institutional Animal Care and Use Committee in the United States, use of invertebrate animals has few guidelines, and many research papers make no mention of how their invertebrate subjects were killed.
Many of the euthanasia methods developed for vertebrates do not transfer well to invertebrates. While a number of euthanasia methods have been proposed for various invertebrate taxa, many have not been adequately vetted, and more research is needed.
Uncertainty over insect sentience
Scientists debate the existence and extent of pain in invertebrates, including insects.
Vincent Wigglesworth suggests giving insects the benefit of the doubt, in case they can suffer. Cornelia Gunkel and Gregory A. Lewbart suggest that "Until the question of pain in invertebrates is clearly answered, an analgesic should be given to any animal that is subjected to a painful procedure." Jeffrey A. Lockwood agrees:
If we use anesthetic and it turns out that insects don’t experience pain, the material cost of our mistake is very low [...]. However, if we don’t use anesthetic and it turns out that the insects were in agony, then the moral cost of our mistake is quite high.
AVMA guidelines echo this perspective:
While there is ongoing debate about invertebrates’ abilities to perceive pain or otherwise experience compromised welfare, the Guidelines assume that a conservative and humane approach to the care of any creature is warranted and expected by society. Consequently, euthanasia methods should be used that minimize the potential for pain or distress.
Laboratory euthanasia
Recommended methods
Pentobarbital overdose
Pentobarbital is an anesthetic drug used in medicine, human and animal euthanasia, and capital punishment. AVMA recommends overdose of pentobarbital or similar drugs as a method of invertebrate euthanasia. The dose can be chosen at comparable levels as those given to poikilotherm vertebrates, adjusted proportionally to the animal's weight. Injection into hemolymph is ideal, but for invertebrates that have an open circulatory system, "an intracoelomic injection" may be required rather than injection into blood vessels. It may help to premedicate the animal with another injected or inhaled drug.
Verifying an insect's death from chemical injections is difficult, so it is often recommended to follow up anesthetic overdose with physical destruction. Note that since insects have different nervous systems from vertebrates, decapitation alone may not always be sufficient to destroy neural function.
Professor Peer Zwart has observed that commercial pentobarbital may have a pH between 9.5 and 11.0, which can coagulate the protein of snail hemocele. This might be painful to a live organism.
Potassium chloride
Potassium chloride (KCl) is one of the three drugs typically used in lethal injection in the United States. It causes hyperkalemia, which stops the heart by inducing depolarization of cellular membrane potentials. Intravenous KCl injection is unacceptable for vertebrate animals unless they have been rendered unconscious by other means.
Development on American lobster:
Andrea Battison and colleagues proposed KCl for euthanasia of the American lobster. The researchers injected KCl solution in order to fill with potassium ions (K+) the hemolymph sinus that holds the lobster's ventral nerve cord and the region around its supraesophageal ganglion. In normal circumstances, neurons maintain a negative membrane potential and have a high intracellular K+ concentration. When KCl is injected into hemolymph, extracellular K+ increases and begins to enter the neurons to restore equilibrium. This depolarizes the neurons and generates an action potential. Subsequent repolarization is blocked by the high intracellular K+, so the nervous system fails, and transmission of adverse sensory information is prevented. The potassium then triggers cardiac arrest within 40–90 seconds, in both warm and cold environments.
While intravenous KCl is not humane for vertebrates, the researchers in this study assume that in lobsters "disruption of the CNS, its ability to process and transmit sensory input, and loss of any awareness would be almost immediate" because the injection directly targets the lobster's "brain". KCl injection produced immediate extension of claws and legs due to deactivation of motor neurons, and the researchers assume that sensory neurons degraded in a similar fashion.
The lethal dose for this procedure was rather high: 1 g KCl per 1 kg of body weight. This was 10–30 times more than the required dose for intravenous mammalian killing with KCl, and it may reflect the lobster's resilient physiology. Tissues were well preserved, except for myofiber damage at the injection site, which means this technique is generally suitable for histology research.
Extension to terrestrial arthropods:
Neil A. C. Bennie and colleagues extended the technique of Battison et al. to arthropods like Blaberus giganteus, Gryllus bimaculatus, and Locusta migratoria. They produced a table of suggested injection sites and doses for ten orders of arthropods. The researchers propose the name targeted hyperkalosis to describe the procedure of injecting a large dose of K+ to the thoracic ganglia. Advantages of this approach are that KCl is cheap, safe, does not need special storage, and preserves specimens for most research use cases except those that look at the neural culture itself. That said, the method is hard to use for small insects like Drosophila sp.
The recommended dose is 10% v/w 300 mg/ml KCl injected between the first pair of legs for Blattodea, Phasmida, Orthoptera, Mantodea, Coleoptera, and Diptera.
Techniques requiring an adjunctive method of euthanasia
Inhaled anesthetics
Overdose on inhaled anesthetics can work for terrestrial invertebrates like insects, but verifying death can be difficult, so it is advised to use another euthanasia method alongside them. Isoflurane and sevoflurane are examples of volatile anaesthetics that can be used; afterward, the insects should be mechanically destroyed such as by crushing. Systems have been developed to provide vaporized anesthetic in the minimal required amounts in order to make anesthesia more cost-effective.
Pithing
Pithing requires sufficient anatomical experience with the relevant species. It is not humane on its own and should be preceded by other means of anaesthesia.
Chemical
Chemicals like alcohol and formalin can destroy nervous tissue but are not humane by themselves and should be preceded by other means of anaesthesia. Ethyl Acetate (EtOAC) or Sodium Cyanide (NaCN) are and were commonly used field chemicals in conjunction with a kill jar for collecting insect specimens by many entomologists.
Freezing
Freezing is sometimes suggested as a method of insect euthanasia. Others contend that freezing is not humane on its own but should be preceded by other means of anaesthesia. Cold by itself does not produce analgesia. Romain Pizzi suggests that freezing, while common in "hobbyist literature", will compromise tissues of spiders for later histopathological examination, but does not make any statement about its effect on spider wellbeing.
The British and Irish Association of Zoos and Aquariums (BIAZA) Terrestrial Invertebrate Working Group (TIWG) reports on a survey conducted by Mark Bushell of BIAZA institutions. He found that refrigeration and freezing were the most common methods "of euthanasia of invertebrates although research has suggested that this is probably one of the least ethical options." That said, freezing is a worst-case method if chemical or instantaneous physical destruction is not possible.
Insects put in an ordinary freezer may require a day or more to be killed.
Uncertain methods
Carbon dioxide is sometimes used for terrestrial invertebrates, including insects. However, its effectiveness is not known. It has been reported to cause convulsions and excited behavior, perhaps suggesting animal discomfort. It is not believed to induce analgesia.
John E. Cooper writes: "If a procedure is considered to be potentially painful, there may be merit in using isoflurane, halothane, or sevoflurane rather than because the extent to which the latter induces analgesia in invertebrates is not known, and its use in vertebrate animals is controversial because of concerns about its effects on the animals' health and welfare."
Farm euthanasia
Some insect farmers believe that mechanical shredding is the least painful way to kill insects suitable for human consumption. Freezing is also commonly used for commercial entomophagy operations, though as discussed above, there is debate over whether freezing is fully humane.
Many insects eaten by humans are roasted, fried, boiled, or otherwise heated directly, without any effort made at euthanasia. Many pets eat live insects, which cannot be euthanized.
See also
Animal euthanasia
Animal testing on invertebrates
Euthanasia in animal testing
Insects in ethics
Lobster killing methods and animal welfare
Notes
Animal euthanasia | Insect euthanasia | [
"Chemistry"
] | 1,957 | [
"Animal testing",
"Animal euthanasia"
] |
47,288,071 | https://en.wikipedia.org/wiki/Altitude3.Net | Altitude3.Net is an electronic business development platform that allows to create web and mobile systems along with interactive communication strategies. The platform has the same functionalities as a content management system (CMS) and communicates with other systems (accounting systems, manufacturing management software (MRP), business management software (enterprise resource planning (ERP)), database, Excel files, XML, CSV or all other kinds of structural data).
Nmédia solutions developed Altitude3.Net in 2001 using Microsoft's .NET Framework technology. The platform is currently using the 4.5 version of Microsoft's Framework.
History
In 2001, Nmédia solutions created the content management system Altitude. As it went on, many versions were developed:
Altitude Moto and Altitude Auto (2001 to 2006);
Altitude 2 (2006);
Altitude3.Net (2010).
List of main functionalities
The Altitude3.Net platform is structured in many modules:
Content management
contact management and mass-emailing
Control of advanced SEO parameters
Microsoft flexibility & computability
Security & access management
Security & permission management
E-commerce solutions: Centralized Product Management (CPM) services. This module includes several functionalities: interface for mass product modification, centralized coupon management, custom management by product group, inventory by store location, shopping cart, price & currency management, catalog management, centralized database, supplier management, product by media, product comparison tool (based on common characteristics), syncing accounting software inventory with Altitude3.Net
A Microsoft Azure solution (cloud computing)
Omnichannel marketing
Other functionalities: On-site search engines for meta data and documents (text, Word, Excel and PDF); HTML5 video player with descending compatibility; Integrated functions enabling an entire site to be generated in Hypertext Markup Language (HTML) or enabling to export all its data (DATA) and import it in any other CMS
Awards and recognitions
In 2011: Nmédia solutions wins the title of Web Development Partner of the Year awarded by the Microsoft Partner Network.
In 2012: Altitude3.Net wins the Prix Franco awarded by the Drummondville Young Chamber of Commerce during its annual gala.
In 2015: The CPM module of Altitude3 is finalist in the Web Solutions category at the Octas.
See also
List of content management systems
References
External links
Content management systems
Data management
Technical communication | Altitude3.Net | [
"Technology"
] | 477 | [
"Data management",
"Data"
] |
47,288,327 | https://en.wikipedia.org/wiki/KDE%20Gear | The KDE Gear is a set of applications and supporting libraries that are developed by the KDE community, primarily used on Linux-based operating systems but mostly multiplatform, and released on a common release schedule.
The bundle is composed of over 200 applications. Examples of prominent applications in the bundle include the file manager Dolphin, document viewer Okular, text editor Kate, archiving tool Ark and terminal emulator Konsole.
Previously the KDE Applications Bundle was part of the KDE Software Compilation.
Extragear
Software that is not part of the official KDE Applications bundle can be found in the "Extragear" section. They release on their own schedule and feature their own versioning numbers. There are many standalone applications like Krita or Amarok that are mostly designed to be portable between operating systems and deployable independent of a particular workspace or desktop environment. Some brands consist of multiple applications, such as Calligra Office Suite. There are several options for obtaining and installing KDE applications under Linux. Moreover, most of the KDE platform and applications have been ported to OpenBSD and NetBSD.
List of applications part of the bundle
Development
Software development
KDE SDK is a collection of two dozen distinct integrated (both within the SDK but also with other KDE applications, e.g. many work with Dolphin, the default file manager) applications and components that work with/are part of KDevelop, and is suitable for general purpose software development in a range of languages. It provides the tooling used to engineer KDE, and is particularly rich in tools to support Qt and C++ development, as well as the more fashionable Rust, Python, etc.
Most of the KDE SDK is available for Windows and macOS in addition to Linux and BSD.
While created for the KDE desktop, prebuilt binary software , including nightly releases, is available for Mac OS, Linux (via AppImage, AppStream or Flathub, as well as Snap), as well as via most major Linux distributions package managers, in addition to the source code via KDE Gitlab.
Windows installers for production/released version of Kate, KDevelop and Umbrello are available as well as via the store.
Several KDE applications are available for Android using the Kirigami framework. built using KDevelop including KDE Connect, KDE Itinerary, a digital travel assistant that integrates train, bus, and air bookings with maps, the KDE Kalendar application, and boarding passes, and KAlgebra, a graphing scientific calculator.
Various other packages are being built for testing on Android, although plans for some of the core parts of the SDK (e.g. Kate) have not been announced.
Unless noted, KDE applications can use KIO slaves for ftp, http, ftp over ssh (fish), Google drive, WebDAV to browse/access files just as they can local files, samba (Windows shared files), archives, man, and info pages. E.g. to browse a WebDAV location, in place of the file path, webdav://www.hostname.com/path/.
The various components can be used on their own (e.g. Kate as a general purpose text editor), or in combination (e.g. Kate uses KDiff3 internally to compare cached autorecovery file with the last saved version).
Kate – an advanced text editor for programmers, and general text editor.
As of KDE 4, KEdit was replaced by Kate and Kwrite.
KDevelop – an integrated development environment for multiple languages, with a plug-in/extension framework (e.g. plug-ins for PHP, Ruby, Python, Markdown documentation authoring/preview, a SVG viewer, etc.), and control flow viewer.
Supported languages include: C/C++ and ObjC (backed by the Clang/LLVM libraries)
Including some extra features for the Qt Framework
Including language support for CUDA and OpenCL
Qt QML and JavaScript, Python, PHP
In addition to the "supported" languages, there is syntax highlighting for a wide range of mark-up, configuration, programming, scripting, and data languages.
GUI integration with multiple different version control systems including Git, Bazaar, Subversion, CVS, Mercurial (hg), and Perforce.
Support for CMake and QMake, as well as generic and custom build files.
Cervisia – CVS frontend
KDESvn – graphical Subversion client
KAppTemplate – Template-based code project generator
KDiff3 – Diff/Patch frontend (see Comparison of file comparison tools)
Kommander – Dynamic dialog editor
Kompare – Diff/Patch frontend
Lokalize – a computer–aided translation system
Okteta - a hex editor
Poxml
Swappo
Clazy Qt-oriented static code analyzer based on the Clang framework
Massif Visualizer – Visualizer for Valgrind Massif data files
Umbrello – UML diagram application
ELF Dissector ELF binary inspector
Fielding REST API tester
Doxyqml Doxygen filter to allow generation of API Documentation for QML
Heaptrack traces all memory allocations and annotates these events with stack traces.
KDebugSettings
KUIViewer views UI files (e.g. from Qt Designer).
Dferry D-Bus library and tools
CuteHMI Open-source HMI (Human Machine Interface) software written in C++ and QML.
Web development
KImageMapEditor – an HTML image map editor
KXSLDbg – an XSLT debugger
Education
Science
Cirkuit – An application to generate publication-ready figures
KBibTeX – an application to manage bibliography databases in the BibTeX format
Semantik – a mindmapping-like tool for document generation
RKWard – an easy to use, transparent frontend to R
KTechLab - an IDE for electronic and PIC microcontroller circuit design and simulation
Games
Toys
AMOR – Amusing Misuse Of Resources. Desktop creature
KTeaTime – Tea cooking timer
KTux
KWeather
Graphics
Internet
Multimedia
Playback
Production
Office
Kontact provides personal information management, backed by the Akonadi framework (including Akregator, KNode, KMail, etc.)
The Calligra Suite provides an office suite, including
Calligra Flow – a flowchart and diagram editor
Calligra Plan – a project management tool
Calligra Sheets – Spreadsheet
Calligra Stage – Presentation application
Calligra Words – Word processor
Kexi – a visual database creator
KEuroCalc – a currency converter and calculator
Kile – integrated LaTeX environment
KMyMoney – a personal finance manager
TaskJuggler – a project management tool
Skrooge – Personal finances manager
LabPlot – a data plotting and analysis tool
LemonPOS – a point of sales application for small and mid–size business
Tellico – a collection organizer
System
Utilities
Accessibility
KMag – a screen magnifying tool
KMouseTool – Automatic Mouse Click
KMouth – a speech synthesizer frontend
Discontinued
Unmaintained Applications
Releases
The KDE Applications Bundle is released every four months and has bugfix releases in each intervening month. A date-based version scheme is used, which is composed of the year and month. A third digit is used for bugfix releases.
With the April 2021 release, the KDE Applications Bundle has been renamed to KDE Gear.
See also
List of GNOME applications
References
External links
KDE applications
Utilities for Linux
Utilities for macOS
Utilities for Windows | KDE Gear | [
"Technology"
] | 1,606 | [
"Computing-related lists",
"Lists of software"
] |
47,289,026 | https://en.wikipedia.org/wiki/Testosterone%20acetate | Testosterone acetate (brand names Aceto-Sterandryl, Aceto-Testoviron, Amolisin, Androtest A, Deposteron, Farmatest, Perandrone A), or testosterone ethanoate, also known as androst-4-en-17β-ol-3-one 17β-acetate, is an androgen and anabolic steroid and a testosterone ester. The drug was first described in 1936 and was one of the first androgen esters and esters of testosterone to be synthesized.
See also
List of androgen esters
References
Acetate esters
Anabolic–androgenic steroids
Androstanes
Ketones
Testosterone esters | Testosterone acetate | [
"Chemistry"
] | 148 | [
"Ketones",
"Functional groups"
] |
47,289,377 | https://en.wikipedia.org/wiki/Breakthrough%20Initiatives | Breakthrough Initiatives is a science-based program founded in 2015 and funded by Julia and Yuri Milner, also of Breakthrough Prize, to search for extraterrestrial intelligence over a span of at least 10 years. The program is divided into multiple projects. Breakthrough Listen will comprise an effort to search over 1,000,000 stars for artificial radio or laser signals. A parallel project called Breakthrough Message is an effort to create a message "representative of humanity and planet Earth". The project Breakthrough Starshot, co-founded with Mark Zuckerberg, aims to send a swarm of probes to the nearest star at about 20% the speed of light. The project Breakthrough Watch aims to identify and characterize Earth-sized, rocky planets around Alpha Centauri and other stars within 20 light years of Earth. Breakthrough plans to send a mission to Saturn's moon Enceladus, in search for life in its warm ocean, and in 2018 signed a partnership agreement with NASA for the project.
History
The Breakthrough Initiatives were announced to the public on 20 July 2015, at London's Royal Society by physicist Stephen Hawking. Russian tycoon Yuri Milner created the Initiatives to search for intelligent extraterrestrial life in the Universe and consider a plan for possibly transmitting messages out into space.
The announcement included an open letter co-signed by multiple scientists, including Hawking, expressing support for an intensified search for alien radio communications. During the public launch, Hawking said: "In an infinite Universe, there must be other life. There is no bigger question. It is time to commit to finding the answer."
The cash infusion is projected to mark up the pace of SETI research over the early 2000s rate, and will nearly double the rate NASA was spending on SETI research annually in approximately 1973–1993.
Projects
Breakthrough Listen
Breakthrough Listen is a program to search for intelligent extraterrestrial communications in the Universe. With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities, it is the most comprehensive search for alien communications to date. The project began in January 2016, and is expected to continue for 10 years.
The project uses radio wave observations from the Green Bank Observatory and the Parkes Observatory, and visible light observations from the Automated Planet Finder. Targets for the project include one million nearby stars and the centers of 100 galaxies. All data generated from the project are available to the public, and SETI@Home is used for some of the data analysis. The first results were published in April 2017, with further updates expected every 6 months.
Breakthrough Message
The Breakthrough Message program is to study the ethics of sending messages into deep space. It also launched an open competition with a US$1 million prize pool, to design a digital message that could be transmitted from Earth to an extraterrestrial civilization. The message should be "representative of humanity and planet Earth". The program pledges "not to transmit any message until there has been a global debate at high levels of science and politics on the risks and rewards of contacting advanced civilizations".
Breakthrough Starshot
Breakthrough Starshot, announced 12 April 2016, is a US$100 million program to develop a proof-of-concept light sail spacecraft fleet capable of making the journey to Alpha Centauri at 20% the speed of light (60,000 km/s or 215 million km/h) taking about 20 years to get there, and about 4 years to notify Earth of a successful arrival.
The interstellar journey may include a flyby of Proxima Centauri b, an Earth-sized exoplanet that is in the habitable zone of its host star in the Alpha Centauri system. From a distance of 1 Astronomical Unit (150 million kilometers or 93 million miles), the four cameras on each of the spacecraft could potentially capture an image of high enough quality to resolve surface features. The spacecraft fleet would have 1000 craft, and each craft, named StarChip, would be a very small centimeter-sized craft weighing several grams. They would be propelled by several ground-based lasers of up to 100 gigawatts. Each tiny spacecraft would transmit data back to Earth using a compact on-board laser communications system. Pete Worden is the head of this project. The conceptual principles to enable this interstellar travel project were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara. METI president Douglas Vakoch summarized the significance of the project, saying that "by sending hundreds or thousands of space probes the size of postage stamps, Breakthrough Starshot gets around the hazards of spaceflight that could easily end a mission relying on a single spacecraft. Only one nanocraft needs to make its way to Alpha Centauri and send back a signal for the mission to be successful. When that happens, Starshot will make history."
In July 2017, scientists announced that precursors to StarChip, named Sprites, were successfully launched and flown.
Breakthrough Watch
Breakthrough Watch is a multimillion-dollar astronomical program to develop Earth- and space-based technologies that can find Earth-like planets in our cosmic neighborhood – and try to establish whether they host life. The project aims to identify and characterize Earth-sized, rocky planets around Alpha Centauri and other stars within 20 light years of Earth, in search of oxygen and other "biosignatures."
Breakthrough Enceladus
Breakthrough Enceladus is an astrobiology space probe mission concept to explore the possibility of life on Saturn's moon, Enceladus. In September 2018, NASA signed a collaboration agreement with Breakthrough to jointly create the mission concept. This mission would be the first privately funded deep space mission. It would study the content of the plumes ejecting from Enceladus's warm ocean through its southern ice crust. Enceladus's ice crust is thought to be around two to five kilometers thick, and a probe could use an ice-penetrating radar to constrain its structure.
See also
Active SETI
Colossus Array Array of 74m telescopes capable of laser propelling nano crafts.
Communication with extraterrestrial intelligence
Interstellar probe
Interstellar travel
IXS Enterprise
Nexus for Exoplanet System Science
Ohio State University Radio Observatory
100 Year Starship
Open data
Open-source software
Project Daedalus
Project Dragonfly
Project Icarus
Project Longshot
Search for extraterrestrial intelligence
SETI@home
Starship
Starwisp
References
External links
Breakthrough Initiatives web site
Breakthrough Listen
Breakthrough Message
Yuri Milner and Stephen Hawking announce $100 million Breakthrough Initiative to dramatically accelerate search for intelligent life in the Universe / Breakthrough Initiatives, London, 20 July 2015
Breakthrough Listen, Breakthrough Initiatives website
Breakthrough Initiatives' official website
Creation of Stephen Hawking's Universe with Nanotechnology
Search for extraterrestrial intelligence
Interstellar messages
Interstellar travel
Proposed space probes
Yuri Milner | Breakthrough Initiatives | [
"Astronomy"
] | 1,412 | [
"Astronomical hypotheses",
"Interstellar travel"
] |
47,289,701 | https://en.wikipedia.org/wiki/Penicillium%20radicum | Penicillium radicum is an anamorph species of the genus of Penicillium which was isolated from rhizosphere of Australian wheat. This species has the ability to solubilise inorganic phosphates, this can promote plant growth Penicillium radicum produces rugulosin
References
Further reading
radicum
Fungi described in 1998
Fungus species | Penicillium radicum | [
"Biology"
] | 79 | [
"Fungi",
"Fungus species"
] |
47,290,509 | https://en.wikipedia.org/wiki/Incidence%20coloring | In graph theory, the act of coloring generally implies the assignment of labels to vertices, edges or faces in a graph. The incidence coloring is a special graph labeling where each incidence of an edge with a vertex is assigned a color under certain constraints.
Definitions
Below G denotes a simple graph with non-empty vertex set (non-empty) V(G), edge set E(G) and maximum degree Δ(G).
Definition. An incidence is defined as a pair (v, e) where is an end point of In simple words, one says that vertex v is incident to edge e. Two incidences (v, e) and (u, f) are said to be adjacent or neighboring if one of the following holds:
v = u, e ≠ f
e = f, v ≠ u
e = {v, u}, f = {u, w} and v ≠ w.
Definition. Let I(G) be the set of all incidences of G. An incidence coloring of G is a function that takes distinct values on adjacent incidences (we use the simplified notation c(v, u) is used instead of c((v, e)).) The minimum number of colors needed for the incidence coloring of a graph G is known as the incidence chromatic number or incidence coloring number of G, represented by This notation was introduced by Jennifer J. Quinn Massey and Richard A. Brualdi in 1993.
History
The concept of incidence coloring was introduced by Brualdi and Massey in 1993 who bounded it in terms of Δ(G). Initially, the incidence chromatic number of trees, complete bipartite graphs and complete graphs was found out. They also conjectured that all graphs can have an incidence coloring using Δ(G) + 2 colors (Incidence coloring conjecture - ICC). This conjecture was disproved by Guiduli, who showed that incidence coloring concept is a directed star arboricity case, introduced by Alon and Algor. His counter example showed that incidence chromatic number is at most Δ(G) + O(log Δ(G)).
Chen et al. found the incidence chromatic number of paths, fans, cycles, wheels, complete tripartite graph and adding edge wheels. Few years later, Shiu et al. showed that this conjecture is true for certain cubic graphs such as cubic Hamiltonian graphs. He showed that in case of outerplanar graph of maximum degree 4, the incidence chromatic number is not 5. The bounds for incidence chromatic number of various graph classes is found out now.
Basic results
Proposition.
Proof. Let v be the vertex with maximum degree Δ in G. Let be the edges that are incident with the vertex v. Consider We can see that every pair of Δ + 1 incidences, that is, is neighborly. Therefore, these incidences have to be colored using distinct colors.
The bound is attained by trees and complete graphs:
If G is a complete graph with at least two vertices then
If G is a tree with at least two vertices then
The main results were proved by Brualdi and Massey (1993). Shiu, Sun and Wu have proposed certain necessary conditions for graph satisfying
The incidence chromatic number of the complete bipartite graph with m ≥ n ≥ 2, is m + 2.
and
Incidence coloring of some graph classes
Meshes
Several algorithms are introduced to provide incidence coloring of meshes like square meshes, honeycomb meshes and hexagonal meshes. These algorithms are optimal. For each mesh, the incidence colors can be made in the linear time with the fewest colors. It is found out that ∆(G) + 1 colors are required for incidence coloring of square meshes, honeycomb meshes and hexagonal meshes.
The incidence chromatic number of a square mesh is 5.
The incidence chromatic number of a hexagonal mesh is 7.
The incidence chromatic number of a honeycomb mesh is 4.
Halin graphs
Chen, Wang and Pang proved that if G is a Halin graph with ∆(G) > 4 then For Halin graphs with ∆(G) = 3 or 4, Jing-Zhe Qu showed to be 5 or 6 respectively. Whether the incidence coloring number of Halin graphs with low degree is Δ(G) + 1 is still an unsolved problem.
Shiu and Sun proved every cubic Halin graph other than has an incidence coloring with Δ(G) + 2 colors. Su, Meng and Guo extended this result to all pseudo-Halin graphs.
If the Halin graph G contains a tree T, then
k-degenerated graphs
D.L. Chen, P.C.B. Lam and W.C. Shiu had conjectured that the incidence chromatic number of a cubic graph G is at most ∆(G) + 2. They proved this for certain cubic graphs such as Hamiltonian cubic graphs. Based on these results, M. H. Dolama, E. Sopena and X. Zhu (2004) studied the graph classes for which is bounded by ∆(G) + c where c is some fixed constant. A graph is said to be k-generated if for every subgraph H of G, the minimum degree of H is at most k.
Incidence chromatic number of k-degenerated graphs G is at most ∆(G) + 2k − 1.
Incidence chromatic number of K4 minor free graphs G is at most ∆(G) + 2 and it forms a tight bound.
Incidence chromatic number of a planar graph G is at most ∆(G) + 7.
Outerplanar graphs
Consider an outerplanar graph G with cut vertex v such that G – v is the union of and . Let (resp. ) be the induced subgraph on vertex v and vertices of (resp. ). Then is the maximum of and where is the degree of vertex v in G.
The incidence chromatic number of an outerplanar graph G is at most ∆(G) + 2. In case of outerplanar graphs with ∆(G) > 3 the incidence chromatic number is ∆(G) + 1.
Since outerplanar graphs are K4-minor-free graphs, they accept a (Δ + 2, 2)–incidence coloring. The solution for incidence chromatic number of the outerplanar graph G having Δ(G) = 3 and 2-connected outerplanar graph is still an open question.
Chordal rings
Chordal rings are variations of ring networks. The use of chordal rings in communication is very extensive due to its advantages over the interconnection networks with ring topology and other analysed structures such as meshes, hypercubes, Cayley's graphs, etc. Arden and Lee first proposed the chordal ring of degree 3, that is, the ring structured network in which every node has an extra link known as chord, to some other node in the network. Distributed loop networks are chordal rings of degree 4 which is constructed by adding 2 extra chords at every vertex in a ring network.
The chordal ring on N nodes and chord length d, denoted by CR(N,d), is a graph defined as:
These graphs are studied due to their application in communication. Kung-Fu Ding, Kung-Jui Pai and Ro-Yu Wu studied the incidence coloring of chordal rings. Several algorithms are formulated to find the incidence chromatic number of chordal rings. The major findings are:
Powers of cycles
Keaitsuda Nakprasit and Kittikorn Nakprasit studied the incidence coloring of powers of cycles, If 2k + 1 ≥ n then so assume n > 2k + 1 and write:
Their results can be summarized as follows:
The relation to incidence coloring conjecture is given by the observation that
Relation between incidence chromatic number and domination number of a graph
Proposition. Let G be a simple connected graph of order n, size m and domination number Then
Proof. Form a digraph D(G) from graph G by dividing each edge of G into 2 arcs in opposite directions. We can see that the total number of arcs in D(G) is 2m. According to Guiduli, the incidence coloring of G is equivalent to proper coloring of the digraph D(G), where 2 distinct arcs and are adjacent if one of the following conditions holds: (i) u = x; (ii) v = x or y = u. By the definition of adjacency of arcs, an independent set of arcs in D(G) is a star forest. Therefore, a maximal independent set of arcs is a maximal star forest. This implies that at least color classes are required.
This relation has been widely used in the characterization of (r + 1)-incidence colorable r-regular graphs. The major result on incidence coloring of r-regular graphs is: If graph G is r-regular graph, then if and only if V(G) is a disjoint union of r + 1 dominating sets.
Interval incidence coloring
Definition. A finite subset is an interval if and only if it contains all the numbers between its minimum and its maximum.
Definition. Let c to be an incidence coloring of G and define
An interval incidence coloring of G is an incidence coloring c such that for each vertex v of G the set is an interval. The interval incidence coloring number of G is the minimum number of colors used for the interval incidence coloring of G. It is denoted by It is clear that If only colors are used for the interval incidence coloring, then it is said to be minimal.
The concept of interval incidence coloring was introduced by A. Malafiejska, R. Janczewski and M. Malafiejski. They proved for bipartite graphs. In case of regular bipartite graphs equality holds. Subcubic bipartite graphs admit an interval incidence coloring using four, five or six colors. They have also proved incidence 5-colorability can be decided in linear time for bipartite graphs with ∆(G) = 4.
Fractional incidence coloring
The fractional version of the incidence coloring was first introduced by Yang in 2007. An r-tuple incidence k-coloring of a graph G is the assignment of r colors to each incidence of graph G from a set of k colors such that the adjacent incidences are given disjoint sets of colors. By definition, it is obvious that 1-tuple incidence k-coloring is an incidence k-coloring too.
The fractional incidence chromatic number of graph G is the infimum of the fractions in such a way that G admits a r-tuple incidence k-coloring. Fractional incidence coloring has great applications in several fields of computer science. Based on incidence coloring results by Guiduli, Yang has proved that the fractional incidence chromatic number of any graph is at most Δ(G) + 20 log Δ(G) + 84. He has also proved the existence of graphs with fractional incidence chromatic number at least Δ(G) + Ω(log Δ(G)).
Nordhaus–Gaddum inequality
Let G be a graph with n vertices such that where denotes the complement of G. Then These bounds are sharp for all values of n.
Incidence coloring game
Incidence coloring game was first introduced by S. D. Andres. It is the incidence version of the vertex coloring game, in which the incidences of a graph are colored instead of vertices. Incidence game chromatic number is the new parameter defined as a game-theoretic analogous of the incidence chromatic number.
The game is that two players, Alice and Bob construct a proper incidence coloring. The rules are stated below:
Alice and Bob color the incidences of a graph G with a set k of colors.
They are taking turns to provide a proper coloring to an uncolored incidence. Generally, Alice begins.
In the case of an incidence that cannot be colored properly, then Bob wins.
If every incidences of the graph is colored properly, Alice wins.
The incidence game chromatic number of a graph G, denoted by , is the fewest colors required for Alice to win in an incidence coloring game. It unifies the ideas of incidence chromatic number of a graph and game chromatic number in case of an undirected graph. Andres found out that the upper bound for in case of k-degenerate graphs is 2Δ + 4k − 2. This bound was improved to 2Δ + 3k − 1 in case of graphs in which Δ is at least 5k. The incidence game chromatic number of stars, cycles, and sufficiently large wheels are also determined. John Y. Kim (2011) has found out the exact incidence game chromatic number of large paths and has given a correct proof of a result stated by Andres concerning the exact incidence game chromatic number of large wheels.
References
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See also
L(h, k)-coloring
Harmonious coloring
Star coloring
Total coloring
Circular coloring
Path coloring
Defective coloring
Radio coloring
Acyclic coloring
Graph coloring | Incidence coloring | [
"Mathematics"
] | 2,715 | [
"Graph coloring",
"Mathematical relations",
"Graph theory"
] |
47,290,842 | https://en.wikipedia.org/wiki/C%C3%A9sar%20Camacho | César Leopoldo Camacho Manco (born 15 April 1943), better known as simply César Camacho, is a Peruvian-born Brazilian mathematician and former director of the IMPA. His area of research is dynamical systems theory.
Camacho earned his Ph.D. from the University of California, Berkeley in 1971 under the supervision of Stephen Smale.
He is a member of the Brazilian Academy of Sciences and a recipient of 1996 TWAS Prize.
Selected publications
C. Camacho, P. Sad. "Invariant varieties through singularities of holomorphic vector fields", Annals of Mathematics, 1982
C. Camacho, A. L. Neto, P. Sad. "Topological invariants and equidesingularization for holomorphic vector fields", Journal of Differential Geometry, 1984
References
1943 births
Living people
Members of the Brazilian Academy of Sciences
Dynamical systems theorists
People from Lima
Instituto Nacional de Matemática Pura e Aplicada researchers
20th-century Brazilian mathematicians
TWAS laureates | César Camacho | [
"Mathematics"
] | 212 | [
"Dynamical systems theorists",
"Dynamical systems"
] |
47,290,906 | https://en.wikipedia.org/wiki/Jos%C3%A9%20Felipe%20Voloch | José Felipe Voloch (born 13 February 1963, in Rio de Janeiro) is a Brazilian mathematician who works on number theory and algebraic geometry and is a professor at Canterbury University.
Career
Voloch earned his Ph.D. from the University of Cambridge in 1985 under the supervision of John William Scott Cassels.
He was a professor at the University of Texas, Austin.
Awards
He is a member of the Brazilian Academy of Sciences.
Selected publications
References
External links
https://scholar.google.com/citations?user=r0Jun08AAAAJ
Brazilian mathematicians
1963 births
Living people
People from Rio de Janeiro (city)
Members of the Brazilian Academy of Sciences
Number theorists
Algebraic geometers
University of Texas at Austin faculty
Alumni of the University of Cambridge
Brazilian expatriate academics in the United States | José Felipe Voloch | [
"Mathematics"
] | 163 | [
"Number theorists",
"Number theory"
] |
47,291,523 | https://en.wikipedia.org/wiki/Ingression%20coast | An ingression coast or depressed coast is a generally level coastline that is shaped by the penetration of the sea as a result of crustal movements or a rise in the sea level.
Such coasts are characterised by a subaerially formed relief that has previously experienced little deformation by littoral (tidal) processes, because the sea level, which had fallen by more than 100 metres during the last glacial period, did not reach its current level until about 6,000 years ago.
Depending on the geomorphological shaping of the flooded landform – e.g. glacially or fluvially formed relief – various types of ingression coast emerge, such as rias, skerry and fjard coasts as well as förde and bodden coasts.
See also
Marine transgression
References
Geomorphology
Hydrology
Coastal and oceanic landforms | Ingression coast | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 177 | [
"Hydrology",
"Environmental engineering"
] |
47,291,762 | https://en.wikipedia.org/wiki/Giovanni%20Forni | Giovanni Forni is an Italian mathematician at the University of Maryland known for his research in dynamical systems.
After graduating from the University of Bologna in 1989, he obtained his PhD in 1993 from Princeton University, under the supervision of John Mather.
He was an invited speaker at the 2002 International Congress of Mathematicians in Beijing.
For his work on solutions of cohomological equations for flows on surfaces, and on the Kontsevich–Zorich conjecture concerning deviation of ergodic averages, he was awarded the 2008 Michael Brin Prize in Dynamical Systems.
In 2012, he became a fellow of the American Mathematical Society.
References
Living people
Italian mathematicians
University of Bologna alumni
Princeton University alumni
University of Maryland, College Park faculty
Fellows of the American Mathematical Society
Dynamical systems theorists
Year of birth missing (living people) | Giovanni Forni | [
"Mathematics"
] | 164 | [
"Dynamical systems theorists",
"Dynamical systems"
] |
47,291,882 | https://en.wikipedia.org/wiki/JamBase | JamBase is an online database and news portal of live music and festivals with a focus on jam bands. It was founded by Andy Gadiel and Ted Kartzman in 1998. The website primarily acts as a service, providing a public API that concert promoters and venues use to publish concert data to the site. The data is also used by third-party developers for other products. In addition to raw data, the website includes a news section publishing information about concerts in a blog format.
, JamBase ranks as the 4,945th most visited sites in the United States according to Alexa, and 27,837th globally.
, JamBase's public API at http://api.jambase.com has been re-enabled, allowing developers to incorporate concert listings into their apps and services.
References
External links
Online databases
1998 establishments in the United States
American music websites | JamBase | [
"Technology"
] | 179 | [
"Computing stubs",
"Computer network stubs"
] |
47,292,164 | https://en.wikipedia.org/wiki/Opposition%20to%20the%20Mauna%20Kea%20Observatories | Opposition to the Mauna Kea Observatories has existed since the first telescope was built in the late 1960s. Originally part of research begun by Gerard Kuiper of the University of Arizona, the site has expanded into the world's largest observatory for infrared and submillimeter telescopes. Opposition to the telescope from residents in the city of Hilo, Hawaii were concerned about the visual appearance of the mountain and Native Hawaiians voiced concerns over the site being sacred to the Hawaiian religion as the home of several deities. Environmental groups and activists have been expressing concern over endangered species habitat.
The Outrigger Telescopes Project, intended to build from four to six comparatively small telescopes for interferometry, was to surround the Keck telescopes. It was cancelled in 2006, after a court found NASA's Environmental Impact Statement was improperly limited to just the telescope area.
An ongoing proposal for one of the world's largest optical telescopes, the Thirty Meter Telescope (TMT) was the focus of protests concerning the continued development of the mountain Hawaiians consider the most sacred peak in the island chain. On 30 October 2018, the Supreme Court of Hawaii approved the resumption of construction of the TMT.
Background
After studying photos for NASA's Apollo program that contained greater detail than any ground-based telescope, Gerard Kuiper began seeking an arid site for infrared studies. While he first began looking in Chile, he also made the decision to perform tests in the Hawaiian Islands. Tests on Maui's Haleakalā were promising but the mountain was too low in the inversion layer and often covered by clouds. On the "Big Island" of Hawaii, Mauna Kea is considered the highest island mountain in the world. While the summit is often covered with snow the air itself is extremely dry. Kuiper began looking into the possibility of an observatory on Mauna Kea. After testing, he discovered the low humidity was perfect for infrared signals. He persuaded then-Governor John A. Burns to bulldoze a dirt road to the summit where he built a small telescope on Puu Poliahu, a cinder cone peak. The peak was the second highest on the mountain with the highest peak being holy ground, so Kuiper avoided it. Next, Kuiper tried enlisting NASA to fund a larger facility with a large telescope, housing and other needed structures. NASA, in turn decided to make the project open to competition. Professor of physics, John Jefferies of the University of Hawaii placed a bid on behalf of the university. Jefferies had gained his reputation through observations at Sacramento Peak Observatory. The proposal was for a two-meter telescope to serve both the needs of NASA and the university. While large telescopes are not ordinarily awarded to universities without well established astronomers, Jefferies and UH were awarded the NASA contract, infuriating Kuiper who felt that "his mountain" had been "stolen" from "him". Kuiper would abandon his site (the very first telescope on Mauna Kea) over the competition and begin work in Arizona on a different NASA project. After considerable testing by Jefferies' team, the best locations were determined to be near the summit at the top of the cinder cones. Testing also determined Mauna Kea to be superb for nighttime viewing due to many factors including the thin air, constant trade winds and being surrounded by sea. Jefferies would build a 2.24 meter telescope with the State of Hawaii agreeing to build a reliable, all weather roadway to the summit. Building began in 1967 and first light seen in 1970.
Expansion renews opposition
In Honolulu, the governor and legislature, enthusiastic about the development, set aside an even larger area for the observatory causing opposition in the main city of the Big Island, Hilo. Native Hawaiians believe the entire site to be sacred and that developing the mountain, even for science, would spoil the area. Environmentalists were concerned about rare native bird populations and other citizens of Hilo were concerned about the sight of the domes from the city. Using town hall meetings, Jefferies was able to overcome opposition by weighing the economic advantage and prestige the island would receive.
There has been substantial opposition to the Mauna Kea observatories that continues to grow. By 1977 Jefferies stated that the Mayor of Hawaii County had joined existing hunting and environmentalist opposition. Over the years, the opposition to the observatories may have become the most visible example of the conflict western science has encountered over access and use of environmental and culturally significant sites. Opposition to development grew shortly after expansion of the observatories commenced. Once access was opened up by the roadway to the summit, skiers began using it for recreation and objected when the road was closed as a precaution against vandalism when the telescopes were being built. Hunters voiced concerns, as did the Hawaiian Audubon Society, which was supported by Governor George Ariyoshi.
The Audubon Society objected to further development on Mauna Kea over concerns to habitat of the endangered palila, an endemic species to only specific parts of this mountain. The bird is the last of the finch billed honeycreepers existing on the island. Over 50% of native bird species had been killed off due to loss of habitat from early western settlers, or the introduction of non-native species competing for resources. Hunters and sportsmen were concerned that the hunting of feral animals would be effected by the telescope operations. A "Save Mauna Kea" movement was inspired by the proliferation of telescopes, with opposition believing development of the mountain to be sacrilegious. Native Hawaiian non-profit groups, such as Kahea, (whose goals are the protection of cultural heritage and the environment), oppose development on Mauna Kea as a sacred space to the Hawaiian religion. Today, Mauna Kea hosts the world's largest location for telescope observations in infrared and submillimeter astronomy. The land itself is protected by the U.S. Historical Preservation Act due to its significance to Hawaiian culture, but this still allowed development.
Outrigger telescopes
Development of the Mauna Kea observatories is still opposed by environmental groups and Native Hawaiians. A 2006 proposal for the Outrigger Telescopes to become extensions of the Keck Observatory was canceled after a judge's determination that a full environmental impact statement must be prepared before any further development of the site. The "outrigger" would have linked the Keck I and Keck II telescopes. Environmental groups and Native Hawaiian activists were much stronger in their opposition this time than they had been in the past, but NASA went ahead with the proposal for lack of an alternate site. The group Mauna Kea Anaina Hou made several arguments against the development, including that Mauna Kea was a sacred mountain to Native Hawaiians where many deities live, and that the cinder cone location being proposed was holy in Hawaiian tradition as a burial site for a demi-god. The group raised several other concerns, such as environmental, concern for the preservation of native insects, the question of Ceded lands, and an audit report critical of the mountain's management.
Thirty Meter Telescope proposal
The Thirty Meter Telescope (TMT) is a proposal for a large, segmented, mirror telescope, planned for the summit of Mauna Kea. The TMT has become a focal point for protests against further development of the observatory site, and a legal battle was fought through the Hawaii court system. The Supreme Court of Hawaii approved the resumption of construction of the telescope on 31 October 2018.
The TMT project is a response to a recommendation in 2000 from the US National Academy of Sciences that a thirty-meter telescope be the top priority and be built within the decade. Urgency in construction is due to the competitive nature of science with the European-Extremely Large Telescope also under construction. Mauna Kea's summit is the most sacred of all the mountains in Hawaii to many, but not all, Native Hawaiian people. Hawaiian cultural practitioners cite impacts to indigenous cultural practice, while recreational users have argued that construction harms the scenic view plane. Some environmentalists are concerned that irreparable ecological damage may be done by construction, although this has been disputed by other environmental advocates. All three groups are represented among the petitioners opposing the TMT. According to the State of Hawaii law HAR 13-5-30, the eight key criteria must be met before construction be allowed on conservation lands in Hawaii. Among other criteria, the development may not "cause substantial adverse impact to existing natural resources within the surrounding area, community, or region," and the "existing physical and environmental aspects of the land must be preserved or improved upon."
Native Hawaiian activists such as Kealoha Pisciotta, a former employee of the Mauna Kea Observatories, have raised concerns over the telescopes on Mauna Kea desecrating what some Native Hawaiians consider to be their most sacred mountain. Pisciotta, a former telescope systems specialist technician at James Clerk Maxwell Telescope, is one of several people suing to stop the construction, and is also director of Mauna Kea Anaina Hou. As of April 2015, two separate appeals were still pending.
The 1998 study Mauna Kea Science Reserve and Hale Pohaku Complex Development Plan Update stated that "...nearly all the interviewees and all others who participated in the consultation process (Appendices B and C) called for a moratorium on any further development on the summit of Mauna Kea."
The Hawaii Board of Land and Natural Resources gave final approval for the project in September 2017 after a protracted hearing process that included a six month long contested case hearing. This decision was challenged in the Hawaii State Supreme Court the following year. The court ruled that the DLNR decision was valid and that construction may proceed.
As of late 2021 construction of the Thirty Meter Telescope remains paused due to the controversy and ongoing effects of the COVID-19 pandemic. The 2020 Decadal report of the National Science Foundation has recommended federal investment in the TMT project. The controversy surrounding construction of the Thirty Meter Telescope continues. Independent polls commissioned by local media organizations show consistent support for the project in the islands with over two thirds of local residents supporting the project. These same polls indicate Native Hawaiian community support remains split with about half of Hawaiian respondents supporting construction of the new telescope.
Ownership change
A July 2022, state law responds to the protests by removing sole control over the master land lease from the University of Hawaii. After a joint transition period from 2023 to 2028, control will shift to the new Mauna Kea Stewardship and Oversight Authority, which will include representatives from the University, astronomers and native Hawaiians.
References
Controversies in the United States
Environmental controversies
Mauna Kea
Astronomical controversies
Mauna Kea
Mauna Kea
Thirty Meter Telescope
Religion and politics
Religion and science
Indigenous peoples and the environment
Environmental racism in the United States | Opposition to the Mauna Kea Observatories | [
"Astronomy"
] | 2,224 | [
"Astronomical controversies",
"History of astronomy"
] |
47,292,238 | https://en.wikipedia.org/wiki/Integer%20complexity | In number theory, the complexity of an integer is the smallest number of ones that can be used to represent it using ones and any number of additions, multiplications, and parentheses. It is always within a constant factor of the logarithm of the given integer.
Example
For instance, the number 11 may be represented using eight ones:
11 = (1 + 1 + 1) × (1 + 1 + 1) + 1 + 1.
However, it has no representation using seven or fewer ones. Therefore, its complexity is 8.
The complexities of the numbers 1, 2, 3, ... are
1, 2, 3, 4, 5, 5, 6, 6, 6, 7, 8, 7, 8, 8, 8, 8, 9, 8, ...
The smallest numbers with complexity 1, 2, 3, ... are
1, 2, 3, 4, 5, 7, 10, 11, 17, 22, 23, 41, 47, ...
Upper and lower bounds
The question of expressing integers in this way was originally considered by . They asked for the largest number with a given complexity ; later, Selfridge showed that this number is
For example, when , and the largest integer that can be expressed using ten ones is . Its expression is
(1 + 1) × (1 + 1) × (1 + 1 + 1) × (1 + 1 + 1).
Thus, the complexity of an integer is at least . The complexity of is at most (approximately ): an expression of this length for can be found by applying Horner's method to the binary representation of . Almost all integers have a representation whose length is bounded by a logarithm with a smaller constant factor, .
Algorithms and counterexamples
The complexities of all integers up to some threshold can be calculated in total time .
Algorithms for computing the integer complexity have been used to disprove several conjectures about the complexity.
In particular, it is not necessarily the case that the optimal expression for a number is obtained either by subtracting one from or by expressing as the product of two smaller factors. The smallest example of a number whose optimal expression is not of this form is 353942783. It is a prime number, and therefore also disproves a conjecture of Richard K. Guy that the complexity of every prime number is one plus the complexity of . In fact, one can show that . Moreover, Venecia Wang gave some interesting examples, i.e. , , , but .
References
External links
Integer sequences | Integer complexity | [
"Mathematics"
] | 530 | [
"Sequences and series",
"Integer sequences",
"Mathematical structures",
"Recreational mathematics",
"Mathematical objects",
"Combinatorics",
"Numbers",
"Number theory"
] |
47,292,772 | https://en.wikipedia.org/wiki/Palo%20Seco%20Forest%20Reserve | Palo Seco Forest Reserve (Bosque Protector Palo Seco), is a rainforest preserve in Panama in Bocas del Toro Province. The reserve was created in 1983 to be a conservation corridor linking Fortuna Forest Reserve and La Amistad International Park, and has an estimated area of 167,410 ha.
Environment
Popular with tree climbers, the reserve includes nutmeg, and ceiba trees. The area is home to tarantulas and eyelash vipers. Palo Seco means dry stick. The reserve has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of many bird species.
See also
Protected areas of Panama
References
Protected areas of Panama
Important Bird Areas of Panama
Tropical rainforests
Forests of Panama
Bocas del Toro Province | Palo Seco Forest Reserve | [
"Biology"
] | 158 | [
"Tropical rainforests",
"Ecosystems"
] |
47,293,002 | https://en.wikipedia.org/wiki/NGC%203059 | NGC 3059 is a barred spiral galaxy. It is located in the constellation of Carina. The galaxy can be described as being faint, large, and irregularly round. It was discovered on February 22, 1835, by John Herschel. The galaxy has been calculated to be 45 - 50 million lightyears from Earth.
References
External links
NGC 3059 - Galaxy - SKY-MAP
NGC 3059 - DeepSkyPedia :: Astronomy
The kinematics of the barred spiral galaxy NGC3059* - Harvard.edu
3059
Carina (constellation)
18350222
Barred spiral galaxies
028298 | NGC 3059 | [
"Astronomy"
] | 127 | [
"Carina (constellation)",
"Constellations"
] |
47,294,125 | https://en.wikipedia.org/wiki/TU%20Corvi | TU Corvi is a yellow-white hued star in the southern constellation of Corvus. It is a dimly visible to the naked eye with an apparent visual magnitude of 6.20. The distance to this star can be estimated from its annual parallax shift of , yielding a range of about 246 light years. Based upon measured changes in its proper motion, it may be a close binary system.
This is an F-type main-sequence star with a stellar classification of F0 V. Previously it had been classed as F0 III, matching an evolved giant star. It is a Delta Scuti variable, varying by an amplitude of 0.025 in B magnitude with a period of 118 minutes. At the age of 786 million years, it has a high rate of spin with a projected rotational velocity of 103 km/s. The star has 1.45 times the mass of the Sun and is radiating 12.6 times the Sun's luminosity from its photosphere at an effective temperature of 7,132 K.
References
F-type main-sequence stars
Delta Scuti variables
Corvus (constellation)
Durchmusterung objects
109585
061496
4797
Corvi, TU | TU Corvi | [
"Astronomy"
] | 254 | [
"Corvus (constellation)",
"Constellations"
] |
47,294,243 | https://en.wikipedia.org/wiki/3%20Corvi | 3 Corvi is a single star in the southern constellation of Corvus, located 192 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.45. This object is moving further from the Earth with a heliocentric radial velocity of +14 km/s.
This is an A-type main-sequence star with a stellar classification of A1 V. It has 2.14 times the mass of the Sun and 1.87 times the Sun's radius. The star is around 900 million years old with a high rate of rotation, showing a projected rotational velocity of 130 km/s. It is radiating ten times the luminosity of the Sun from its photosphere at an effective temperature of 9,671 K. An infrared excess has been detected, suggesting that a debris disk with a temperature of 150 K is orbiting from the host star.
References
A-type main-sequence stars
Circumstellar disks
Corvus (constellation)
Durchmusterung objects
Corvi, 3
105850
059394
4635 | 3 Corvi | [
"Astronomy"
] | 235 | [
"Corvus (constellation)",
"Constellations"
] |
47,294,360 | https://en.wikipedia.org/wiki/W%20Corvi | W Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 11.16 to 12.5 over 9 hours. Its period has increased by 1/4 second over a century. It is an unusual system in that its two stars are very close to each other yet have different surface temperatures and hence thermal transfer is not taking place as expected.
References
Corvus (constellation)
Beta Lyrae variables
Corvi, W | W Corvi | [
"Astronomy"
] | 98 | [
"Corvus (constellation)",
"Constellations"
] |
47,294,401 | https://en.wikipedia.org/wiki/6%20Corvi | 6 Corvi is a single star in the southern constellation of Corvus, located 341 light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.66. This object is moving closer to the Earth with a heliocentric radial velocity of −2.4 km/s. It is an evolved giant star with a stellar classification of K1 III. The star has expanded to 13.6 times the Sun's radius and is radiating 75.5 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,608 K.
References
K-type giants
Corvus (constellation)
Durchmusterung objects
Corvi, 6
107815
060425
4711 | 6 Corvi | [
"Astronomy"
] | 169 | [
"Corvus (constellation)",
"Constellations"
] |
47,294,802 | https://en.wikipedia.org/wiki/Steve%20Ward%20%28computer%20scientist%29 | Steve Ward is Professor of Computer Science and Engineering at MIT, where his recent teaching and research activities revolve around areas of computer system architecture. He holds three degrees from MIT – a Bachelor of Science and a Master of Science in Electrical Engineering and a PhD in Computer Science.
One of his research projects, the 1979 Nu machine, became a model for microprocessor-based workstations. Numerous software products have been created due to inspiration of its UNIX port and system software, and the NuBus was an industry standard from the late 1980s to the mid 1990s. In the late 1970s Professor Steve Ward and his research group at MIT's Laboratory for Computer Science (LCS) developed the TRIX operating system. Ward's inventions include a novel dynamic memory chip architecture and a real-time controller design. He was involved with the Curl project, which aimed to formulate a new language for creating web documents with almost any sort of content, from simple formatted text to complex interactive applets, in the 90s. In the early 2000s he worked on organic computing – alternative ways of building systems so that they behave more like organisms than like conventional computer systems.
References
Living people
American computer scientists
Date of birth missing (living people)
Year of birth missing (living people) | Steve Ward (computer scientist) | [
"Technology"
] | 257 | [
"Computing stubs",
"Computer specialist stubs"
] |
47,294,873 | https://en.wikipedia.org/wiki/Monitor%20mount | A monitor mount is a supportive bracket or arm designed to hold up a computer monitor, laptop, notebook or other display screen. Monitor arm and monitor bracket are other common terms for this device.
History
Flat panel monitors became increasingly popular as the technology grew less expensive during early to mid 2000s. These lighter monitors were better suited for a wider range of movement than the heavier cathode ray tube monitor that was previously sold with most computers. The patent for inventing the monitor mount belongs to Rob Mossman and is dated from September 20, 2006; however monitor mounts have been available for at least six years before the patent was issued. Several companies like Ergotron, Multibrackets ab, Mount- it, Loctek and Herman Miller have been producing mounts since the early 2000s.
Significance
The added functionality of monitor mounts has made them very popular. Depending on the model, monitor mounts can move up and down, rotate, tilt, retract and swivel.
VESA is an organization that manages the standards for mounting solutions. In 1997, VESA came up with a standard hole size and screwing pattern for flat panel screens, called Flat Display Mounting Interface (usually known as VESA mount), which is still valid today. Almost all monitor mounts follow this VESA standard in one form or another. Monitor manufacturers typically create a standard VESA hole pattern on the back of the monitor for mounting purposes.
Health advantages
A monitor mount placed at the appropriate height, distance and angle can help “prevent possible health effects such as excessive fatigue, eye strain, and neck and back pain.” Monitor mounts are especially important for anyone using a standing or walking desk because of the dynamic height and stability requirements for those applications.
Monitor mounts offer ergonomic benefits by allowing users to adjust screen height, tilt, and angle, promoting a neutral neck position and reducing musculoskeletal strain. They help minimize eye strain by ensuring an optimal viewing distance and angle. By freeing up desk space, mounts support better posture, leading to reduced muscle fatigue. Dual or triple screen setups enhance productivity and decrease cognitive fatigue. Proper screen positioning, especially in dynamic work environments like adjustable desks, ensures consistent ergonomic benefits.
Types
Installation
Wall-mounted – mounts onto a wall.
Clamp – clamp hardware fastens to edge of a desk.
Grommet – hardware is inserted through a hole in the desk and secured underneath.
Common workstation setups
Single monitor arm – the most common usage.
Multiple monitor arms – with the rise of multi-screen setups, mounts with multiple monitor arms are becoming more common.
Laptop arm – designed to support a laptop.
Mixed-use – dual-arm mount supporting a monitor and a laptop or tablet.
Portable monitor mounts - designed with travelers in mind, they securely fasten monitors to tables or other surfaces.
References
Computer peripherals | Monitor mount | [
"Technology"
] | 577 | [
"Computer peripherals",
"Components"
] |
47,295,185 | https://en.wikipedia.org/wiki/RV%20Corvi | RV Corvi is an eclipsing binary star system in the southern constellation of Corvus. The brightness of the pair regularly ranges in apparent visual magnitude from 8.6 down to 9.16 over a period 18 hours, even the brightest of which is too faint to be visible to the naked eye. The system is located at a distance of approximately 690 light-years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of ~19 km/s.
The variability of this system was discovered by H. H. Swope. In 1942, Irene G. Buttery published an orbital period of 0.74728 days for the system, showing this is an eclipsing binary. It is a near-contact binary with both stars showing the effect of tidal interactions and the facing sides are less than 10% of the orbital separation apart, but are not in contact. One or both stars may show an excess of luminosity on their facing sides. The system is composed of stars of spectral types F0 and G0, which orbit each other every 0.7473 days.
References
Beta Lyrae variables
Corvus (constellation)
109796
061620
Corvi, RV
F-type main-sequence stars | RV Corvi | [
"Astronomy"
] | 261 | [
"Corvus (constellation)",
"Constellations"
] |
47,295,528 | https://en.wikipedia.org/wiki/Baxalta | Baxalta (Bax from the name of its former parent company; alta a Latin adjective meaning 'high' or 'profound') is a biopharmaceutical company founded on 1 July 2015 after its parent company, Baxter International, spun off biopharmaceutical division. The company began its operation with a revenue of $6 billion, and is now a subsidiary of Takeda Pharmaceutical Company.
Company history
Baxalta inherited all of its parent company's on-the-market treatments, focused on hemophilia, The company aimed to launch 20 in-development projects by 2020, heaping $2.5 billion in annual sales. Before being spun off, Baxalta acquired SuppreMol (a German company) for 225 million. Baxalta also acquired the blockbuster leukemia drug Oncaspar from Sigma-Tau Finanziaria S.p.A. for 900 million.
In August 2015, Shire Plc made an unsolicited $30.6 billion stock offer for the company increasing the Baxalta share price over 16%. Baxalta investors would be set to receive 0.1687 of Shire's American Depositary Receipts for every share they hold, representing a premium of 36%, compared to the company's stock price on August 3. This deal would create the largest global biotech company focused solely on rare diseases.
In 2016 the company was acquired by Shire for $32 billion. Subsequently, Shire was acquired by Takeda Pharmaceutical Company for $62 billion in January 2019.
References
Biopharmaceutical companies
2016 mergers and acquisitions
Biotechnology companies of the United States
Pharmaceutical companies established in 2015
Biotechnology companies established in 2015
Biotechnology companies disestablished in 2016
Pharmaceutical companies disestablished in 2016
Corporate spin-offs
Baxter International | Baxalta | [
"Biology"
] | 363 | [
"Biotechnology stubs",
"Medical technology stubs",
"Medical technology"
] |
47,296,221 | https://en.wikipedia.org/wiki/SX%20Corvi | SX Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 8.99 to 9.25 over 7.6 hours. The system is a contact binary also known as a W Ursae Majoris variable, where the two component stars orbit closely enough to each other for mass to have been transferred between them—in this case the secondary having transferred a large amount of mass to the primary.
Yildiz and colleagues estimated the age of the system at 7.32 ± 0.97 billion years based on study of the properties of the system and estimated rate of mass transfer. They found the current masses of the primary and secondary to be 1.25 ± 0.04 and 0.10 ± 0.01 solar masses respectively, from their original masses of 0.72 ± 0.02 and 1.68 ± 0.05 solar masses.
References
Corvus (constellation)
W Ursae Majoris variables
F-type main-sequence stars
061825
110139
Corvi, SX | SX Corvi | [
"Astronomy"
] | 217 | [
"Corvus (constellation)",
"Constellations"
] |
47,297,286 | https://en.wikipedia.org/wiki/N%20conjecture | In number theory, the n conjecture is a conjecture stated by as a generalization of the abc conjecture to more than three integers.
Formulations
Given , let satisfy three conditions:
(i)
(ii)
(iii) no proper subsum of equals
First formulation
The n conjecture states that for every , there is a constant depending on and , such that:
where denotes the radical of an integer , defined as the product of the distinct prime factors of .
Second formulation
Define the quality of as
The n conjecture states that .
Stronger form
proposed a stronger variant of the n conjecture, where setwise coprimeness of is replaced by pairwise coprimeness of .
There are two different formulations of this strong n conjecture.
Given , let satisfy three conditions:
(i) are pairwise coprime
(ii)
(iii) no proper subsum of equals
First formulation
The strong n conjecture states that for every , there is a constant depending on and , such that:
Second formulation
Define the quality of as
The strong n conjecture states that .
References
Conjectures
Unsolved problems in number theory
Abc conjecture | N conjecture | [
"Mathematics"
] | 223 | [
"Unsolved problems in mathematics",
"Unsolved problems in number theory",
"Conjectures",
"Abc conjecture",
"Mathematical problems",
"Number theory"
] |
68,486,066 | https://en.wikipedia.org/wiki/Ibrahim%20Kalil%20Konat%C3%A9 | Ibrahim Kalil Konaté (2 August 1955 – 14 August 2021) was a Guinean politician and computer scientist.
He served as and was Chairman of the Board of Directors of the Loterie nationale de Guinée.
Biography
Konaté was born in Kankan on 2 August 1955 and attended primary school at the École primaire Dramé Oumar Kankan. In 1998, he earned a degree in mathematical science from the Lycée Aviation Conakry. He also earned a degree in management informatics from the Université International Collège.
Ibrahim Kalil was appointed Minister of National Education and Literacy on 27 February 2017 and served until 26 May 2018. He served as Chairman of the Board of Directors of the Loterie nationale de Guinée from 29 January 2019 until his death.
Ibrahim Kalil Konaté died of COVID-19 in Conakry on 14 August 2021, at the age of 66.
Awards
COPE-Guinée Prize for good performance (2017)
References
1955 births
2021 deaths
Government ministers of Guinea
Rally of the Guinean People politicians
Computer scientists
People from Kankan
Deaths from the COVID-19 pandemic in Guinea | Ibrahim Kalil Konaté | [
"Technology"
] | 227 | [
"Computer science",
"Computer scientists"
] |
68,486,117 | https://en.wikipedia.org/wiki/WASP-159 | WASP-159 is a faint star located in the southern constellation Caelum. With an apparent magnitude of 12.84, a powerful telescope is needed to see the star. The star is located based on parallax, but is drifting away with a heliocentric radial velocity of +35.16 km/s.
Properties
WASP-159 is a F-type subgiant with 1.41 times the Sun's mass, and double the Sun's radius. It radiates at 4.78 times the Sun's luminosity from its photosphere at an effective temperature of 6,120 K. WASP-159 is about 3 billion years old, and is metal-rich like many other planetary hosts.
Planetary system
In 2019, SuperWASP discovered an inflated "hot Jupiter" orbiting the star.
References
F-type subgiants
Caelum
Planetary systems with one confirmed planet
Hot Jupiters | WASP-159 | [
"Astronomy"
] | 188 | [
"Caelum",
"Constellations"
] |
68,487,448 | https://en.wikipedia.org/wiki/MotoStudent | MotoStudent is a biennial competition between students from universities around the whole world that consist in that these students design, manufacture and develop a prototype of competition motorcycle over a year and a half.
Finally, these prototypes compete in an event at MotorLand Aragón, a circuit situated in Alcañiz, in Aragón, Spain.
Since the beginning of the competition, universities from 20 countries have participated in some edition.
History
This competition was born in Aragón, Spain, becoming an alternative to Formula SAE. On it, students must, on the one hand, present a viable project for the mass production of a motorcycle that they themselves design (calling this part of the competition as MS1), and on the other, manufacture the designed motorcycle, to later evaluate its performance in a final event alongside the rest of the participants (receiving the name of MS2).
Initially, the only existing category was for prototypes with petrol engine, being a 125 cc and 2-stroke engine from Gas Gas brand. This first edition, in which 23 teams participated, mostly Spanish and Italian, culminated in autumn 2010, with a final event on the MotorLand Aragón track, where the final event of the competition has been held each edition since.
The second edition took place between 2011 and 2012, with lower reception, as the number of registered teams was reduced to 18. In this new edition the regulations were adapted to become similar to the newly created moto3 category, replacing the engine used in the previous edition by a 4-stroke and 250 cc, this time, made by Yamaha.
In the third edition, held between 2013 and 2014, the number of participating teams increased to 33, consolidating this event at an international level. Sherco was the brand of the engines supplied to the participants on this occasion.
In the fourth edition, which took place between 2015 and 2016, a category for 100% electric prototypes was included for the first time. On this occasion, 35 teams are registered in the "petrol" category, powered by a Honda engine, while 17 new teams decide to venture into the newly created "electric" category.
The fifth edition, carried out between the years 2017 and 2018, represents the continuity of the competition in both categories, as it has a high acceptance by increasing to 47 teams registered in the petrol category, and to 27 in the electric. The brand that supplied the gasoline engines on this occasion was KTM.
The sixth edition should have been held between 2019 and 2020, but due to the exceptional situation derived from the COVID-19 pandemic, various postponements took place that lengthened the duration until 2021, with the competition taking place definitively in July of the year. 88 were the teams registered between the two categories, being the historical maximum of participation. To date, it has been the only edition in which an engine model has been repeated in the petrol category, being again supplied by KTM.
During the seventh edition, carried out between the years 2022 and 2023, 32 teams participated in the Petrol category and 48 in the Electric category. Also for this edition, the combustion engine is supplied by KTM (SXF 250cc); the electric motor, instead, by Circe.
The eighth edition of MotoStudent is now underway.
List of winners
The prizes that are distributed in the competition are for the best project (MS1), the best design, the best innovation, the best team adding the points from MS1 plus those from MS2 (global), the best rookie, as well as the three first classified in the MS2 phase, as this is the most relevant as it reflects the behavior of the prototypes in competition.
Podium in the "Petrol" MS2 category
Podium in the "Electric" MS2 category
References
Student sports competitions
Mechanical engineering competitions
World motorcycle racing series | MotoStudent | [
"Engineering"
] | 772 | [
"Mechanical engineering competitions",
"Mechanical engineering"
] |
68,488,293 | https://en.wikipedia.org/wiki/Neptunium%20silicide | Neptunium silicide is a binary inorganic compound of neptunium and silicon with the chemical formula . The compound forms crystals and does not dissolve in water.
Synthesis
Heating neptunium trifluoride with powdered silicon in vacuum:
Physical properties
Neptunium silicide forms crystals of tetragonal crystal system, space group I41/amd, cell parameters: a = 0.396 nm, c = 1.367 nm, Z = 4.
Neptunium disilicide does not dissolve in water.
Chemical properties
Neptunium disilicide reacts with HCl:
References
Neptunium(III) compounds
Silicon compounds
Inorganic compounds
Silicides | Neptunium silicide | [
"Chemistry"
] | 146 | [
"Inorganic compounds"
] |
68,488,480 | https://en.wikipedia.org/wiki/Plutonium%20silicide | Plutonium silicide is a binary inorganic compound of plutonium and silicon with the chemical formula PuSi. The compound forms gray crystals.
Synthesis
Reaction of plutonium dioxide and silicon carbide:
Reaction of plutonium trifluoride with silicon:
Physical properties
Plutonium silicide forms gray crystals of orthorhombic crystal system, space group Pnma, cell parameters: a = 0.7933 nm, b = 0.3847 nm, c = 0.5727 nm, Z = 4, TiSi type structure.
At a temperature of 72 K, plutonium silicide undergoes a ferromagnetic transition.
References
Plutonium compounds
Silicon compounds
Inorganic compounds
Silicides | Plutonium silicide | [
"Chemistry"
] | 145 | [
"Inorganic compounds"
] |
68,488,976 | https://en.wikipedia.org/wiki/Lichenopeltella%20cetrariicola | Lichenopeltella cetrariicola is a species of lichenicolous fungus belonging to the class Dothideomycetes. It has been reported from Europe and Iceland but it probably has a more widespread distribution. It has been reported from at least two host species, Cetraria islandica and Cetraria aculeata.
References
Dothideomycetes
Fungi described in 1989
Fungi of Europe
Lichenicolous fungi
Taxa named by William Nylander (botanist)
Fungi of Iceland
Fungus species | Lichenopeltella cetrariicola | [
"Biology"
] | 104 | [
"Fungi",
"Fungus species"
] |
68,489,181 | https://en.wikipedia.org/wiki/Muellerella%20pygmaea | Muellerella pygmaea is a species of lichenicolous fungus in the family Verrucariaceae. It has a cosmopolitan distribution in Arctic-alpine areas and grows on the thallus and apothecia of a number of hosts.
Host species for Muellerella pygmaea include:
Acarospora sp.
Acarospora smaragdula
Aspicilia calcarea
Candelariella aurella
Carbonea assentiens
Lecanora alpigena
Lecanora muralis
Lecanora polytropa
Lecidea grisella
Lecidea lapicida
Lecidea obluridata
Tephromela atra
Rhizocarpon geographicum
Rusavskia elegans
References
Verrucariales
Fungi described in 1855
Taxa named by Gustav Wilhelm Körber
Fungi of Iceland
Fungus species | Muellerella pygmaea | [
"Biology"
] | 173 | [
"Fungi",
"Fungus species"
] |
68,489,574 | https://en.wikipedia.org/wiki/Plutonium%28IV%29%20nitrate | Plutonium (IV) nitrate is an inorganic compound, a salt of plutonium and nitric acid with the chemical formula Pu(NO3)4. The compound dissolves in water and forms crystalline hydrates as dark green crystals.
Synthesis
Crystals of dark green to black-green composition Pu(NO3)4•5H2O precipitate with a slow (months) evaporation of a solution of a plutonium (IV) compound in nitric acid.
Physical properties
Plutonium (IV) nitrate forms a crystalline hydrate of the composition Pu(NO3)4•5H2O—dark green crystals of rhombic crystal structure, space group F dd2, cell parameters: a = 1.114 nm, b = 2.258 nm, c = 1.051 nm, Z = 8.
Crystalline hydrate melts in its own crystallization water at 95–100 °C.
It dissolves well in nitric acid (dark green solution) and water (brown solution). Also dissolves in acetone and ether.
Chemical properties
When heated to 150–180 °C, it decomposes with autooxidation to plutonium (VI) with the formation of plutonyl nitrate (PuO2(NO3)2).
Upon evaporation of concentrated nitric acid solutions of plutonium nitrate and alkali metal nitrates, double nitrates of the composition M2[Pu(NO3)6] are formed, where M = Cs+, Rb+, K+, Tl+, NH4+, analogous to ceric ammonium nitrate.
Toxicity
Plutonium nitrate is both radioactive and extremely toxic due to its high solubility in water.
References
Plutonium(IV) compounds
Nitrates | Plutonium(IV) nitrate | [
"Chemistry"
] | 358 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
68,490,782 | https://en.wikipedia.org/wiki/Larreineta%20funicular | The Larreineta funicular (; ) is a funicular railway in the municipality of Valle de Trápaga-Trapagaran in the Basque Country, Spain. It links the downtown with the neighborhood of Larreineta.
History
The construction of the funicular was first proposed in 1912. Construction started in 1920 and after several delays, it was inaugurated in 1926. Originally, it carried both passengers and freight. In 1985, it was transferred to the Basque Government, and since 1994 it has been operated by Euskotren.
Operation
Services run every 30 minutes throughout most of the day. Tickets can be bought at the stations, or the Barik card can be used.
References
External links
Funicular railways in Spain
Rail transport in the Basque Country (autonomous community)
Euskotren
1200 mm gauge railways in Spain
1926 establishments in Spain
Railway lines opened in 1926
Mining railways
Tourist attractions in the Basque Country (autonomous community) | Larreineta funicular | [
"Engineering"
] | 188 | [
"Mining equipment",
"Mining railways"
] |
68,490,860 | https://en.wikipedia.org/wiki/Import%E2%80%93export%20%28logic%29 | In propositional logic, import-export is a name given to the propositional form of Exportation:
.
This already holds in minimal logic, and thus also in classical logic, where the conditional operator "" is taken as material implication.
In the Curry-Howard correspondence for intuitionistic logics, it can be realized through currying and uncurrying.
Discussion
Import-export expresses a deductive argument form. In natural language terms, the formula states that the following English sentences are logically equivalent:
If Mary isn't at home, then if Sally isn't at home, then the house is empty.
If Mary isn't home and Sally isn't home, then the house is empty.
There are logics where it does not hold and its status as a true principle of logic is a matter of debate. Controversy over the principle arises from the fact that any conditional operator that satisfies it will collapse to material implication when combined with certain other principles. This conclusion would be problematic given the paradoxes of material implication, which are commonly taken to show that natural language conditionals are not material implication.
This problematic conclusion can be avoided within the framework of dynamic semantics, whose expressive power allows one to define a non-material conditional operator which nonetheless satisfies import-export along with the other principles. However, other approaches reject import-export as a general principle, motivated by cases such as the following, uttered in a context where it is most likely that the match will be lit by throwing it into a campfire, but where it is possible that it could be lit by striking it. In this context, the first sentence is intuitively true but the second is intuitively false.
If you strike the match and it lights, it will light.
If the match lights, it will light if you strike it.
See also
Counterfactuals
Modus ponens
Paradoxes of material implication
Strict conditional
Currying
References
Theorems in propositional logic
Classical logic
Formal semantics (natural language) | Import–export (logic) | [
"Mathematics"
] | 407 | [
"Theorems in propositional logic",
"Theorems in the foundations of mathematics"
] |
68,493,199 | https://en.wikipedia.org/wiki/2020%20China%20bolide | The 2020 China bolide was observed on December 23, 2020 at 07:23:33 local time (December 22, 2020 at 23:23:33 UTC) when a bright fireball, suspected to be a meteor, was seen flying from north to south and then exploding over mostly Tibetan-inhabited areas of the People's Republic of China.
Overview
The bolide's trajectory was from north to south and had a low inclination (5°±2°) relative to the local surface. According to CNEOS, the approximate location of the airburst was roughly near the border of the Tibet Autonomous Region and the Qinghai province.
According to CNEOS, it was the most energetic fireball, in terms of radiated energy, to happen anywhere over land since the 2013 Chelyabinsk meteor. It was the most energetic fireball to happen anywhere on Earth (sea or land) since December 2018, when a more energetic fireball was observed over the Bering Sea.
Also, it was the largest recorded meteor to fall over China at least in two decades, radiating much more energy than the 2017 China bolide and the 2000 China bolide.
The large fireball lit up the sky about an hour before sunrise, and was caught on video.
The China Earthquake Networks Center posted information about a suspected bolide near the border between Nangqian County and Yushu County (both of which are in the Qinghai province) on their social media account. They said no one was injured.
References
2020 in China
Modern Earth impact events
2020 in outer space
December 2020 events in China
21st-century astronomical events | 2020 China bolide | [
"Astronomy"
] | 327 | [
"Astronomical events",
"21st-century astronomical events"
] |
68,495,683 | https://en.wikipedia.org/wiki/2020%20Summer%20Olympic%20pictograms | The 2020 Summer Olympic pictograms are visual graphic symbols used to represent each sport in competition games of the 2020 Summer Olympics.
Formation
The Tokyo 2020 Organising Committee (TOCOG) produced the official sports pictograms of the Tokyo 2020 Olympic Games, due to the need to communicate visually to an increasingly international group of athletes and spectators, while paying great respect to the Olympic sport pictograms, which were first introduced at the 1964 Tokyo Olympic Games.
The designer team led by was in charge of the creation of the Official "Olympic Games sport pictograms". All rights, including copyrights, regarding the produced the Official Pictograms belong to the TOCOG. After the Olympic and Paralympic Games, it is expected to be under the jurisdiction of the International Olympic Committee (IOC).
Works
The Olympic Games Tokyo 2020 sport pictograms were released on 12 March 2019 (500 days to the originally scheduled opening ceremony), they are designed to subtly communicate the characteristics and athleticism of each sport, as well as artistically highlighting the dynamism of athletes.
Hiromura reveals in a newspaper interview that he needs to go back to the origin of pictograms, "information transmission", and to be simple. So that, for example, for golf, boxing, and other things that can be expressed only by the upper body he does not draw the lower body. On the other hand, he says he pursued realism and activity in simplicity. The evolution of the pictograms to show the dynamics and reality of athletes is, for example, that "I studied body movements and made the torso white in many sports. It is better not to draw the torso. I noticed that the condition of the abdominal muscles and the twist of the waist are easily transmitted."
A total of 50 pictogram designs for the 33 sports of the 2020 Tokyo Olympic were produced (for example, five for the individual disciplines within cycling).
Opening ceremony
The 2020 Summer Olympics opening ceremony included a video sequence in which a performer represented each in turn of the pictograms. Time Out described it as "a funny, witty performance reminiscent of a typical Japanese TV game show".
The design of Paralympic pictograms and kinetic sport pictograms
The Tokyo 2020 "Paralympic Games sport pictograms" were also handled by Masaaki Hiromura's team, and 23 pictogram designs were produced for the 22 sports of the 2020 Tokyo Paralympics (there were separate pictograms for road cycling and track cycling, within the sport of cycling). Emphasis was placed on expressing a sense of dynamism by studying the rules of the Paralympic Games, how to use the body of para-athletes, and equipment such as wheelchairs for para-athletes.
When both the Olympic Sport Pictograms and the Paralympic Sport Pictograms of Tokyo 2020 are collectively referred to, the name of the Tokyo 2020 Sport Pictograms is often used.
Furthermore, in 2020, "Kinetic Sport Pictograms", which are developments of the sport pictograms based on dynamic concepts such as motion-designed logomark, were unveiled. This work was supervised by video designer , and the product could be viewed on the digital signage inside the stadium.
References
External links
Hiromura Design Office
Anjo City Museum of History
2020 Summer Olympics
Pictograms
Graphic design
Infographics
Symbols introduced in 2019 | 2020 Summer Olympic pictograms | [
"Mathematics"
] | 698 | [
"Symbols",
"Pictograms"
] |
68,495,847 | https://en.wikipedia.org/wiki/Selenate%20selenite | A selenate selenite is a chemical compound or salt that contains selenite and selenate anions (SeO32- and SeO42-). These are mixed anion compounds. Some have third anions.
Naming
A selenate selenite compound may also be called a selenite selenate.
Production
One way to produce a selenate selenite compound is to evaporate a water solution of selenate and selenite compounds.
Properties
On heating, selenate selenites lose SeO2 and O2 and yield selenites, and ultimately metal oxides.
Related
Related to these are the sulfate sulfites and tellurate tellurites. They can be classed as mixed valent compounds.
List
References
Selenates
Selenites
Mixed anion compounds | Selenate selenite | [
"Physics",
"Chemistry"
] | 161 | [
"Ions",
"Matter",
"Mixed anion compounds"
] |
68,495,982 | https://en.wikipedia.org/wiki/LZTFL1 | Leucine zipper transcription factor like 1 also known as LZTFL1 is a ubiquitously expressed protein which localizes to the cytoplasm and in humans is encoded by the LZTFL1 gene.
Function
This protein regulates protein trafficking to the ciliary membrane through interaction with the Bardet-Biedl syndrome (BBS) complex of proteins.
Clinical significance
Mutations in the LZTFL1 gene are associated with Bardet-Biedl syndrome, and the gene also acts as a tumor suppressor through regulation of epithelial-mesenchymal transition.
Identified as the gene on chromosome 3 at location 3p21.31 responsible for mediating an associated with genetic susceptibility to SARS-CoV-2 infection and COVID-19 respiratory failure. The DNA segment conferring the risk is inherited from Neanderthals.
References
Proteins
Human genetics | LZTFL1 | [
"Chemistry"
] | 186 | [
"Proteins",
"Biomolecules by chemical classification",
"Molecular biology"
] |
68,496,223 | https://en.wikipedia.org/wiki/Fireproof%20banknote | The fireproof banknote is a demonstration of putting a banknote, previously soaked in 50% (v/v) alcohol fuel solution, to a flame. The fire is lit and later extinguished by itself without the banknote being burnt. This demonstration can be used to teach about the fire triangle and classes of fire.
Explanation
A 50% (v/v) alcohol solution is composed of 50% alcohol and 50% water in which water acts as a solvent. By igniting a paper banknote completely soaked with 50% alcohol solution, the alcohol (which is the fuel in the fire triangle) is combusted into carbon dioxide and water vapour. Contrarily water is heated up, with some being evaporated as it absorbs energy from the combustion of alcohol. The evaporating water helps cool down the system, so not all water is evaporated and the paper banknote is not burnt. The water-to-alcohol ratio should be 50% or higher; a lower ratio leads to the banknote being slightly burnt because there is not enough water to absorb the combustion energy and cool down the system.
CnH2n+1OH + (3n/2) O2 → n CO2 + (n+1) H2O
Common alcohol fuels for this experiment can be methanol (n=1), ethanol (n=2) and both isomers of propanol (n=3). The fire lit in this scenario is categorized as a class B fire (fire from flammable liquids), while the fire from burning paper (banknote) is categorized as class A. The alcohol-water mixture flame can be hard to detect, so sodium chloride can be added to give the flames an orange-yellow color. For safety purpose, a water tray should be prepared for emergency use in case a paper banknote caught a fire, and flammable and combustible materials should not be kept or put near the flame.
Alternative materials or setups
Other materials
Euro banknotes are recommended since it is made of paper and it is legally permitted to artistically mutilate it or burn in small amounts. Moreover, there are no depictions of any persons on the banknotes.
Aside from banknotes, a similar experiment can be performed by using towels, paper or exam paper.
Other setups
No material
A solution of about 50% fuel alcohol and 50% water can catch on fire and extinguish itself in a "burning water" demonstration. In contrast to the subsection above, this can be done in a glassware without any absorbing materials like banknotes, towels, or paper.
No fuel
Tap water may be added to a paper bag which then is put on a stove to boil. The paper bag can absorb water, which cools down the system and prevents the paper bag from being burnt.
Gallery
References
Banknotes
Chemistry classroom experiments
Articles containing video clips
Fire protection | Fireproof banknote | [
"Chemistry",
"Engineering"
] | 592 | [
"Building engineering",
"Fire protection",
"Chemistry classroom experiments"
] |
68,496,538 | https://en.wikipedia.org/wiki/LamaH | LamaH (Large-Sample Data for Hydrology and Environmental Sciences) is a cross-state initiative for unified data preparation and collection in the field of catchment hydrology. Hydrological datasets, for example, are an integral component for creating flood forecasting models.
Features
LamaH datasets always consist of a combination of meteorological time series (e.g., precipitation, temperature) and hydrologically relevant catchment attributes (e.g., elevation, slope, forest area, soil, bedrock) aggregated over the respective catchment as well as associated hydrological time series at the catchment outlet (discharge). By evaluating the large and heterogeneous sample (large-sample) of catchments, it is possible to gain insights into the hydrological cycle that would probably not be achievable with local and small-scale studies. The structure of the dataset allows an evaluation based on machine learning methods (deep learning). The accompanying paper explains not only the data preparation but also any limitations, uncertainties and possible applications.
Difference to CAMELS
The LamaH datasets are quite similar to the CAMELS datasets, but additionally feature:
Further basin delineations (based on intermediate catchments) and attributes (e.g. flow distance and altitude difference between two topologically adjacent discharge gauges), enabling the setup of a interconnected hydrological network
Attributes for classifying catchments and runoff gauges according to the degree and type of (anthropogenic) influence
Availability
LamaH datasets are available for the following regions:
Central Europe (Austria and its hydrological upstream areas in Germany, Czech Republic, Switzerland, Slovakia, Italy, Liechtenstein, Slovenia and Hungary) / 859 catchments
CAMELS datasets are available for (ranked by publication date):
Contiguous USA (exclusive Alaska and Hawaii) / 671 catchments
Chile / 516 catchments
Brazil / 897 catchments
Great Britain / 671 catchments
Australia / 222 catchments
Both the CAMELS and LamaH datasets are licensed with Creative Commons and are therefore available barrier-free for the public.
References
Hydrology
Datasets in machine learning | LamaH | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 439 | [
"Hydrology",
"Environmental engineering"
] |
68,496,606 | https://en.wikipedia.org/wiki/Weijian%20Zhou | Weijian Zhou is a geologist at the Chinese Academy of Sciences known for her research into environmental changes in the Quaternary era using radiocarbon data.
Education and career
Zhou graduated from Guizhou University in 1976. She earned her Ph.D. in 1995 from North-West University in China in 1995, and her Ph.D. won the “First National Prize for the One Hundred Most Outstanding PhD Theses in China”. In 1999, she became a professor in the Institute of Earth Environment at the Chinese Academy of Sciences in Xi'an, China. In 2006 she began her position as the director of the Xi'an Accelerator Mass Spectrometry Center.
In 2016, she was named a fellow of the American Geophysical Union who cited her "for exceptional contributions to radiocarbon dating and our understanding of East Asian and global environmental changes using radionuclides as tracers".
Research
Weijian Zhou is known for using Accelerator mass spectrometry data to track geochemical tracers such as beryllium-10 in loess and Carbon-14. Through these data streams, Zhou studies to chronostratigraphy in the Quaternary era, the period from 2.9 million years ago to the present. Her research has provided insights into the monsoons in China, and records of ancient rainfall through tracking of beryllium-10 in dust layers. During the COVID-19 pandemic, Zhou's research showed carbon dioxide concentrations were lower than previous years, but this decrease was short-lived because values returned to pre-pandemic levels when lockdown restrictions were lifted.
Selected publications
Awards and honors
Academician, Division of Earth Sciences, Chinese Academy of Sciences (2009)
Elected member, Academy of Sciences for the Developing World (2010)
Fellow, American Geophysical Union (2016)
References
Fellows of the American Geophysical Union
Members of the Chinese Academy of Sciences
Guizhou University alumni
North-West University alumni
Chinese women chemists
21st-century Chinese geologists
Chinese geochemists
Year of birth missing (living people)
Living people
20th-century Chinese chemists
21st-century Chinese chemists
Chinese women geologists | Weijian Zhou | [
"Chemistry"
] | 433 | [
"Geochemists",
"Chinese geochemists"
] |
68,496,655 | https://en.wikipedia.org/wiki/Assouad%E2%80%93Nagata%20dimension | In mathematics, the Assouad–Nagata dimension (sometimes simply Nagata dimension) is a notion of dimension for metric spaces, introduced by Jun-iti Nagata in 1958 and reformulated by Patrice Assouad in 1982, who introduced the now-usual definition.
Definition
The Assouad–Nagata dimension of a metric space is defined as the smallest integer for which there exists a constant such that for all the space has a -bounded covering with -multiplicity at most . Here -bounded means that the diameter of each set of the covering is bounded by , and -multiplicity is the infimum of integers such that each subset of with diameter at most has a non-empty intersection with at most members of the covering.
This definition can be rephrased to make it more similar to that of the Lebesgue covering dimension. The Assouad–Nagata dimension of a metric space is the smallest integer for which there exists a constant such that for every , the covering of by -balls has a refinement with -multiplicity at most .
Relationship to other notions of dimension
Compare the similar definitions of Lebesgue covering dimension and asymptotic dimension. A space has Lebesgue covering dimension at most if it is at most -dimensional at microscopic scales, and asymptotic dimension at most if it looks at most -dimensional upon zooming out as far as you need. To have Assouad–Nagata dimension at most , a space has to look at most -dimensional at every possible scale, in a uniform way across scales.
The Nagata dimension of a metric space is always less than or equal to its Assouad dimension.
References
Metric geometry
Dimension theory | Assouad–Nagata dimension | [
"Mathematics"
] | 347 | [
"Mathematical analysis",
"Mathematical analysis stubs"
] |
68,497,022 | https://en.wikipedia.org/wiki/Neptunium%28IV%29%20nitrate | Neptunium(IV) nitrate is an inorganic compound, a salt of neptunium and nitric acid with the chemical formula Np(NO3)4. The compound forms gray crystals, dissolves in water, and forms crystal hydrates.
Synthesis
Addition of dilute nitric acid to freshly prepared neptunium(IV) hydroxide:
Physical properties
Neptunium(IV) nitrate forms gray hygroscopic crystals.
It is soluble in water.
It forms a crystal hydrate of the composition Np(NO3)4•2H2O.
References
Neptunium compounds
Nitrates | Neptunium(IV) nitrate | [
"Chemistry"
] | 129 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
65,603,732 | https://en.wikipedia.org/wiki/Comparison%20of%20open-source%20mobile%20phones | The scope for this page is that used for list of open-source mobile phones.
Mobiles currently in production
Mobiles expected to be in production
Mobiles no longer in production
See also
Comparison of mobile operating systems
List of open-source mobile phones
References
Mobile Linux
Mobile phone standards
Lists of computer hardware
Open-source mobile phones
Open-source mobile phones | Comparison of open-source mobile phones | [
"Technology"
] | 71 | [
"Computing-related lists",
"Computing comparisons",
"Lists of computer hardware"
] |
65,607,527 | https://en.wikipedia.org/wiki/FSO%20Nabarima | FSO Nabarima is a floating storage and offloading vessel that is permanently moored offshore of Venezuela at the Corocoro oil field in the Gulf of Paria, located between Venezuela and the island of Trinidad. After production at Corocoro ceased in 2019 following United States sanctions on the Venezuelan state oil company Petróleos de Venezuela (PDVSA) and following years of neglect, Nabarima fell into a state of disrepair, and was reported in 2020 to be at risk of spilling her cargo of about 1.3 million barrels of crude oil.
Description
FSO Nabarima is a floating storage and offloading vessel, without motors, that is permanently moored offshore of Venezuela at the Corocoro oil field in the Gulf of Paria and whose main purpose was to receive the petroleum produced by the mixed company Petrowarao, in Delta Amacuro state. Nabarima used to be held with nine anchors and is connected to a long pipeline system.
Operations
Nabarima, with a capacity of 1.4 million barrels of oil, was built in 2005 by Samsung Heavy Industries in South Korea for ConocoPhillips, which at the time operated the Corocoro field. In 2007, Hugo Chávez expropriated ConocoPhillips' assets in Venezuela and the country seized control of Corocoro and Nabarima, which passed into the control of Petrosucre, a joint venture of PDVSA, which owns 74%, and Italian oil company Eni, which owns the remaining 26%.
In early 2019, Petrosucre shut down production at Corocoro after the United States placed sanctions on PDVSA that prevented Petrosucre from exporting oil to Citgo, which had previously purchased Corocoro oil. After years of neglect, Nabarima fell into a state of disrepair. Russ Dallen, head of Caracas Capital Markets, who closely tracks Venezuela’s maritime industry, said that the ship “should not be in this shape except for neglect and stupidity.” An industry executive, who spoke to The Associated Press on the condition of anonymity for fear of retaliation, said the lack of maintenance appeared to have damaged valves in the ballast system used to stabilise the ship.
Shutdown
Following the Corocoro shutdown, Nabarima was abandoned with about 1.3 million barrels of crude aboard. For months, opposition leaders and petroleum union leaders warned that the tanker was listing and at risk of sinking and causing a significant environmental disaster. Government spokespeople denied this. Nabarima is a double-hulled tanker, which offers some security. According to complaints made by PDVSA workers, its main process, control, auxiliary and security equipment was inoperative due to "lack of maintenance and management incompetence", the tanker being operated with a skeleton crew, although designed to be operated by 80 workers. In July 2020 Nabarima began listing to starboard, followed by a leak into her engine room the following month that failed bilge pumps were unable to pump out. According to Eudis Girot, the leader of the Unitary Federation of Petroleum Workers of Venezuela, there was about of water in the lower decks of Nabarima by early September and the Associated Press reported that she continued to list about 5 degrees to starboard, though PDVSA said that her condition was "satisfactory" and Eni considered the vessel "stable." Girot warned of the possibility of an environmental disaster occurring. The ship was filled almost to its maximum capacity of 1.4 million barrels of crude, about five times the amount the Exxon Valdez spilled in 1989. Critics of PDVSA have said the tanker is an example of the government's corruption and mismanagement. At the time, Eni was negotiating with the United States Treasury Department for permission to offload the oil on board.
On 17 August, El Pitazo published a video in which petroleum workers denounced the poor conditions of the vessel. On 1 September, Girot said that conditions faced by the three workers on board were subhuman since they did not have lifeboats, the fire extinguishers had expired, the bathrooms had collapsed, they had little food and coexisted with rats. The following day an inspection was ordered and on 8:45 a.m. (VET) Manuel Parra, PDVSA Supply and Commerce manager, arrived in a helicopter to carry out an inspection. On 3 September, it was announced that the tanker was not at risk of sinking anymore; the following day Girot affirmed that elements of Maduro's government "planned the sinking of the Nabarima tanker.
Nabarima remained listing in mid-October, when Reuters reported that crews were undertaking repairs to the ship while Eni continued discussions with the US government "in order to prevent any sanctions risk." On 16 October, the United States embassy in Trinidad and Tobago declared that the sanctions against Venezuela were not designed to affect "security, environmental or humanitarian activities". National Assembly deputy Robert Alcalá declared on 17 October that the Assembly must pressure for the immediate removal of the vessel and fix the damage to prevent major environmental harm. Several days later, Reuters reported that the list had been corrected, while PDVSA was said to be planning to transfer oil off of Nabarima to at least one of the company's tankers. A visit by a team of experts from Trinidad and Tobago confirmed that the list had been corrected, and a tank barge and oil tanker have been designated for removal of 550,000 barrels of oil for delivery to Venezuela.
On 2 November, the United States Department of State assured that Eni's efforts to prevent an oil spill would not be in conflict with the sanctions and expressed its support for the emergency reparations. The following day the National Assembly of Venezuela held Maduro's administration responsible for the deterioration of Nabarima and requested that the United Nations Office for Project Services and the International Maritime Organization urgently inspect the vessel. The Assembly also asked Italian company Eni to follow the experts recommendations for the immediate offload of the oil from the board. Nueva Esparta state Tobías Bolívar deputy declared that of the original 80 petroleum workers only six remained on board the vessel.
See also
FSO Safer
References
2005 ships
Ships built by Samsung Heavy Industries
Floating production storage and offloading vessels | FSO Nabarima | [
"Chemistry"
] | 1,300 | [
"Floating production storage and offloading vessels",
"Petroleum technology"
] |
65,609,397 | https://en.wikipedia.org/wiki/Alarm%20photosynthesis | Alarm photosynthesis is a variation of photosynthesis where calcium oxalate crystals function as dynamic carbon pools, supplying carbon dioxide (CO2) to photosynthetic cells when stomata are partially or totally closed. This biochemical appendance of the photosynthetic machinery is a means to alleviate the perpetual plant dilemma of using atmospheric CO2 for photosynthesis and losing water vapor, or saving water and reducing photosynthesis. The function of alarm photosynthesis seems to be rather auxiliary to the overall photosynthetic performance. It supports a low photosynthetic rate, aiming at the maintenance and photoprotection of the photosynthetic apparatus rather than a substantial carbon gain.
History
The alarm photosynthesis process was first evidenced in pigweed Amaranthus hybridus plant in 2016 when A. hybridus leaves were exposed to drought conditions or exogenous application of abscisic acid. The same study showed similar results in Dianthus chinensis, Pelargonium peltatum, and Portulacaria afra plants under drought stress. In 2018, the alarm photosynthesis process was exhibited in A. hybridus plants under controlled CO2 starvation conditions. In 2020, evidence of this process was shown in the Antarctic extremophile plant Colobanthus quitensis under CO2 limiting conditions.
Mechanism
Under stress conditions (e.g. water deficit) oxalate released from calcium oxalate crystals is converted to CO2 by an oxalate oxidase enzyme and the produced CO2 can support the Calvin cycle reactions. Reactive hydrogen peroxide (H2O2), the byproduct of oxalate oxidase reaction, can be neutralized by catalase.
Differences against CAM and C4
Alarm photosynthesis represents an unknown photosynthetic variation to be added to the already known C4 and CAM pathways. However, alarm photosynthesis, in contrast to these pathways, operates as a biochemical pump that collects carbon from the organ interior (or from the soil) and not from the atmosphere.
See also
Photosynthesis
Crassulacean acid metabolism
C4 carbon fixation
C3 carbon fixation
References
Photosynthesis | Alarm photosynthesis | [
"Chemistry",
"Biology"
] | 453 | [
"Biochemistry",
"Photosynthesis",
"Chemical process stubs"
] |
65,610,457 | https://en.wikipedia.org/wiki/Lettuce%20hem | A lettuce hem is a frilled hem invented by Stephen Burrows. The hem was popular in the disco era for how it added movement to a garment.
Description
The lettuce hem is named for its resemblance to a lettuce leaf. The hem gets its characteristic waves from a zig-zag overlock stitching pattern typical of Burrows' work, which emphasized rather than concealed hems and stitching. The technique is mostly used on knit textiles such as jersey fabric, which allow the hem to hold its shape.
History
Stephen Burrows invented the lettuce hem in the 1970s. The nature of the invention is disputed, with The Museum at FIT characterizing the invention as arising from a sewing error while the FIDM Museum claims he was inspired by Diana Vreeland requesting a garment in "lettuce green." Regardless, the hem became a signature of Burrows and remained popular throughout the decade.
The style reemerged in the 1990s, particularly on knit "babydoll" style T-shirts. Lettuce hems became popular again in the late 2010s and early 2020s, largely as a reference to the 1990s iteration of the trend. With the increased interest in upcycling old and thrifted clothing during this period, the lettuce hem became a way to update a garment. The patchwork top, which features lettuce hems all across the garment rather than just along the edges, enjoyed popularity starting in 2020.
References
Parts of clothing
1970s fashion | Lettuce hem | [
"Technology"
] | 306 | [
"Components",
"Parts of clothing"
] |
65,610,859 | https://en.wikipedia.org/wiki/Starfish%20regeneration | Starfish, or sea stars, are radially symmetrical, star-shaped organisms of the phylum Echinodermata and the class Asteroidea. Aside from their distinguishing shape, starfish are most recognized for their remarkable ability to regenerate, or regrow, arms and, in some cases, entire bodies. While most species require the central body to be intact in order to regenerate arms, a few tropical species can grow an entirely new starfish from just a portion of a severed limb. Starfish regeneration across species follows a common three-phase model and can take up to a year or longer to complete. Though regeneration is used to recover limbs eaten or removed by predators, starfish are also capable of autotomizing and regenerating limbs to evade predators and reproduce.
Due to their wide range of regenerative capabilities, starfish have become model organisms for studying how the regenerative process has evolved and diversified over time. While the overall morphological processes have been well documented in many starfish, little is known regarding the underlying molecular mechanisms that mediate their regeneration. Moreover, some researchers hope starfish may one day serve as inspiration for therapeutics aiming to expand the extent to which humans can repair and replace damaged cells or tissues.
Degrees of regeneration
Regenerative ability differs greatly among starfish species, but can generally be classified within three categories: unidirectional regeneration, disk-dependent bidirectional regeneration, and disk-independent bidirectional regeneration. In each case, regenerative capacity is enabled by the uniquely simple body plan of starfish.
The typical starfish has five or more arms, or "rays", radiating from a central disk. Each arm contains a copy of vital organs and is equipped with eyespots, an eye-like structure that helps the starfish differentiate between light and darkness, and tube feet, which enable locomotion. All organs connect to the digestive system in the central disk, which also contains the starfish mouth and stomach. This replication and delocalization of vital organs makes starfish especially resilient to the loss of appendages. In addition to being able to replicate organs, starfish are also capable of regenerating neuron cells. Other cells that are left over from the injury are able to become neural cells and take up functions they would not normally do. Following injury or amputation, a star fish can survive with its remaining organ copies during the period of regeneration, which ranges from a few months to over a year.
Unidirectional regeneration
Though the different Asteroidea species show a great range of variation in regeneration capabilities, an overwhelming number of them have the ability to regenerate lost limbs and tube feet. Star fish that exhibit unidirectional regeneration, or regeneration that is restricted to a single direction, are capable of regenerating multiple lost limbs from a disk containing half or more of the original starfish. Unidirectional regeneration is the simplest form of regeneration as the majority of the disk is intact, allowing the starfish to eat, move, and escape predators during the regeneration period. Unidirectional regeneration is also the most common form of regeneration exhibited by starfish as single arms are often removed by predators or shed through autotomy.
Crown-of-thorns starfish (Acanthaster planci), which feed on large swaths of western Pacific coral reefs, are notable unidirectional regenerators. Starfish of this invasive species are extremely difficult to eradicate because of their ability to regrow when half or more of the original starfish is intact. Thus, initial population control efforts championed by fishermen and conservationists in the 1960s, which involved sectioning and releasing caught starfish, may have unknowingly exacerbated population outbreaks in the western Pacific coral reefs.
Disk-dependent bidirectional regeneration
Bidirectional regeneration is a robust form of regeneration defined by the ability to regrow the main body axis after whole body severance. Starfish that exhibit disk-dependent bidirectional regeneration are capable of regenerating a full starfish when less than half of the original starfish is intact, given that all or part of the central disk is present. The presence of the central disk gives the detached limb access to its original digestive system and mouth, allowing the starfish to move to find food, eat, and hide from predators during recovery.
Disk-independent bidirectional regeneration
The most extensive form of regeneration exhibited by starfish species is disk-independent bidirectional regeneration. In this rare case, a detached starfish limb with no remnants of the central disk is capable of regenerating a full starfish, referred to as a comet form. In the absence of a mouth or digestive system, the detached arm survives on nutrients stored in the arm until it can regenerate a disk. Without the ability to feed during recovery, disk independent bidirectional regeneration is difficult to execute and requires that the detached arm is in a relatively healthy form. This vigorous form of regeneration has been identified in Linckia species to a very high degree.
Regeneration phases
Regeneration is an intrinsically conservative post-embryonic developmental process that repairs and replaces cells, tissues, organs, and body parts of a given organism. Furthermore, the arm regenerative process of all starfish species studied to date can be subdivided into three distinct phases: a repair phase, an early regenerative phase, and an advanced regenerative phase. Although diversity exists among starfish in terms of their physiology, morphology, and amputation susceptibility, a generalized regenerative process can be appreciated. Throughout the regeneration process, the coelomic epithelium is vital. This is a tissue that plays a large role in the formation of new limbs and new organs. Note, the following section details the regrowth of a starfish's arm following amputation in a unidirectional manner of regeneration.
Repair phase
Immediately following amputation, all starfish must seal their coelomic cavities, particularly the perivisceral coelomic canal, to prevent fluid loss and the entrance of foreign pathogens. This is initially achieved by an emergency mechanism in which the entire arm wall contracts swiftly and powerfully to form a 'hemostatic ring' of sorts.
Additionally, in a process analogous to mammalian platelet clot formation, a morphologically heterogenous population of coelomocytes help prevent the loss of body fluid by forming a clot of cells at the injured perivisceral coelomic canal. Coelomocytes are free-wandering cells that circulate the coelomic fluid, possessing phagocytic, clotting, and cytotoxic functions in most echinoderms. These coelomocytes not only form clots at starfish amputation sites but also help clear the wound site of debris and foreign microorganisms via phagocytosis.
Re-epithelialization occurs within the first 48 hours post-amputation, in the middle of the repair phase. Interestingly, in contrast to most mammals, starfish accomplish re-epithelialization without any immediate proliferation of epidermal progenitor cells at the wound edge or wound epithelium. Rather, epidermal cells are stretched inwards from the wound edge, expanding centripetally until a continuous layer is formed. Of note, these stretched epidermal cells maintain their cell-cell junctions in starfish, whereas in mammals, junctional complexes are disrupted to allow the migration of keratinocytes over the wound. Subsequently, the wound epithelium becomes increasingly differentiated, thicker, and permanent. Moreover, in some starfish species, such as Echinaster sepositus and Acanthaster planci, a phagocytic syncytium transiently supports the migration of epithelial cells while protecting injured stump tissue from fluid loss and foreign entities.
Finally, the end of the repair phase is marked by the formation of a temporary edematous area below the newly established epithelial layer. Overall, this provisional tissue matures over time, to ultimately provide a scaffold for regenerative growth. In many ways, the edematous area resembles the granulation tissue of mammals, possessing a disorganized mix of fibroblasts, phagocytes, nervous elements, differentiating myocytes, and undifferentiated cells. Early on, phagocytes clear the edematous area of foreign material and degrade leftover debris. Meanwhile, fibroblasts develop the extracellular matrix (ECM) and pockets of collagen fibril. The area progressively matures over the span of about a week, ultimately containing a more organized extracellular matrix, dispersed collagen fibril bundles, nerve elements, early pigment cells, and other differentiated or undifferentiated cells.
Early regenerative phase
The early regenerative phase begins once the injury has healed, and is characterized by an exodus of dedifferentiating myocytes from various anatomical structures towards the regenerating tip. Throughout this phase, the regenerating coelomic cavities serve as a physical driving force of regrowth. Notably, excess fluid secretion from the coelomic epithelia produces a hypertrophic appearance in the regenerating tip of the coelomic cavities. This hypertrophic state, in turn, produces a pressure that supports the regrowth of canals, particularly the perivisceral coelom and the radial water canal. In addition, the pressure creates a turgidity that physically supports the regenerate's shape until skeleton and muscle formation can occur.
The early regenerative phase is marked by a large mobilization of various cytotypes from different locations (like the coelomic cavities) towards the edematous regenerating region. This proximal to distal migration of cells supports the outgrowth of the radial nerve cord from any existing nerve cord remaining post amputation. Intriguingly, the radial nerve cord and radial water canal (the only two structures that run continuously along the arm) occur in tandem and potentially include an inductive cross-talk relationship. However, it is not currently known which structure induces regrowth and differentiation of the other. Furthermore, initial regeneration of the radial nerve cord results from proliferation of existing structure as well as the differentiation of supporting cells that create cell 'niches' for future neuronal growth. Specifically, the supporting cells (believed to be glial cells) acquire a bipolar shape, implanting opposing cytoplasmic extensions containing regenerative intermediate filament bundles. Niches result from these extensions and house interspersed neurons over time.
A blastema-like region also appears during this phase composed of undifferentiated and barely differentiated cells amongst the epidermal tissue and coelom outgrowths (radial water canal and radial nerve cord). Moreover, the perivisceral coelom funnels undifferentiated cells to the blastema-like formation. Unlike a true blastema, this blastema-like area lacks localization, contains an abundant ECM, and houses organized fiber bundles of collagen. As such, while starfish generally follows a morphallactic process of regrowth, the regenerative mechanisms fall somewhere in between a true morphallactic and epimorphic model, in reality.
Early skeletogenesis also begins during the early regenerative phase as plates of calcium carbonite deposit into the collagen network developing in the former edematous area. Importantly, near the end of the phase, a small regenerate appears. While less organized than the starfish stump, the regenerate houses the beginnings of a transverse meshwork of collagen fibers, differentiated ossicles, and stereom. Moreover, the pressurized radial water canal starts regenerating the terminal tube foot. This is the first defined structure to regenerate, as cells flow from the inner coelomic walls to the lumen of the tube feet, where they differentiate amongst rearranging muscles.
Advanced regenerative phase
The last phase – known as the advanced regenerative phase – consists of extensive morphogenesis and differentiation of numerous tissues across the regenerate. The small regenerate that emerges from the early regenerative phase will morph into a miniature starfish arm come 3–6 months post amputation. This miniaturized arm will resemble the non-regenerating arms of the starfish, and will continue growing throughout the organism's lifetime.
Importantly, and especially evident in the last phase, starfish re-growth follows a "distalization-intercalary" regenerative model after arm amputation. In this model, the organism first forms the most distal (far away from the stump) structure during regeneration. This new structure, in turn, behaves as a signaling center to organize the development of new structures in relation to old stump tissue. Subsequently, regenerated tissues manifest – or, more accordingly, intercalate – between the limb's stump and the newly formed distal structure. As noted above, the terminal tube foot is the first defined structure to appear, serving as the distal signaling center that coordinates subsequent regeneration in a proximal to distal direction.
Massive myogenesis (formation of muscular tissue) occurs throughout the advanced regenerative phase. Majority of the muscles regenerate via the same mechanism: dedifferentiated cells from the coelomic body cavity travel towards the regenerating starfish tip before re-differentiating into muscle components. Meanwhile, a basal lamina gradually develops around the forming muscle tissue to separate it from the coelomic cavities. In this manner, terminal tube foot formation is followed by the growth of additional tube feet, ampullae, aboral ossicles, and other musculoskeletal structures in a proximal to distal direction until regeneration is completed.
Cellular differentiation and completion of the main nervous components take place in the regenerate during this phase. For example, function is regained in the radial nerve cord as it finishes development. Additionally, a densely packed region of glial cells, dendrites, and axons called the neuropil zone reappears. Over time, pigment-cupped photoreceptors called ocelli develop, leading to the full restoration of the optic cushion (collection of ocelli). Notwithstanding, the specific mechanisms of neurogenesis throughout this phase remain relatively unknown: the exact role of stem cell, dedifferentiation, and cellular differentiation requires further exploration.
Autotomy and regeneration
Though starfish are well understood to utilize their regenerative capabilities to regrow arms eaten or damaged by predators, they are also capable of regenerating arms they have intentionally shed through a process known as autotomy. Researchers propose that autotomy mediated regeneration may play a role in predator evasion as well as both sexual and asexual reproduction.
Predator evasion
Autotomy is understood to serve a defensive function in starfish. While arms can be pulled off the starfish body by predators, the starfish can choose to shed its arm in order to evade danger. If the detached limb is eaten or extremely damaged, bidirectional regeneration is unlikely. There are two ways a starfish can lose its limbs from predators. The loss of limbs includes losing an entire limb or multiple from large prey, or flesh being eaten away by smaller prey. Large prey can eat the starfish whole, whereas smaller prey will turn over a starfish and eat at their soft flesh. Although it is unlikely for bidirectional regeneration, the original starfish can regenerate its lost arm or arms through unidirectional regeneration.
Sexual reproduction
Starfish sexually reproduce through spawning, meaning that sex cells (eggs and sperm) are released into the water and fertilized outside of the body. Each arm contains gonads that swell with eggs and sperm in female and male starfish, respectively. Early observations of Labidiaster starfish found that autotomized arms were swollen with mature eggs, suggesting that autotomy may be utilized for sexual propagation. Under this theory, starfish shed their arms in order to increase the range of egg dispersion and thus increase the possibility of eggs being fertilized by neighboring male starfish. Once the egg has been fertilized a blastula is formed. After the formation of the blastula cilia is produced on the cell allowing the cell to move through the water. When the cell later turns into larva, the starfish larva will start to produce its organs before turning into an adult starfish. The host starfish then regenerates the lost arm through unidirectional regeneration. This theory is challenged by two findings in Lamarck starfish. The first being that very young Lamarck starfish with underdeveloped gonads exhibit autonomy, and the second being that in Hawaii, Lamarck starfish shed arms throughout the year irrespective of spawning season.
Asexual reproduction
In asexual starfish reproduction, starfish develop offspring identical to the parent. This can be achieved through arm autotomy or fission. In arm autotomy, starfish typically shed arms with part of the central disk attached. This arm regenerates into a full starfish identical to the original through disk-dependent bidirectional regeneration. In some species, disk independent bidirectional regeneration is utilized to produce new starfish. Several species also produce larvae that are capable of asexual reproduction prior to adulthood through autotomy and budding.
A less commonly used form of asexual reproduction is fissiparity, reproduction via the division of the disk. This phenomenon is observed in various degrees in the genres Coscinasterias, Stephanasterias, and Sclerasterias. In Sclerasterian starfish, fission is restricted to young organisms, while Coscinasterian and Stephanasterian starfish maintain this ability into adulthood. Six-armed starfish capable of fission split their disk into two three-arm halves that both regenerate into a six-armed starfish. Starfish with seven arms are split into a three-arm and four-arm halves, which both regenerate into a seven arm starfish.
See also
Starfish
Echinoderm
Regeneration (biology)
Water vascular system
Wound healing
References
Further reading
Starfish (Sea Stars) | National Geographic. (2010, September 10). Animals.
Carnegie Mellon University. The Future of Human Healing Lies in the Brain of a Starfish—News—Carnegie Mellon University. http://www.cmu.edu/news/stories/archives/2020/march/dahl-starfish.html
Scientists Search Starfish For Key to Human Regeneration | WIRED. (n.d.). Retrieved October 26, 2020, from https://www.wired.com/2007/04/scientists-sear/
All About Starfish. (2017, September 5). Smithsonian Science Education Center. https://ssec.si.edu/stemvisions-blog/all-about-starfish
Healing
Developmental biology
Senescence | Starfish regeneration | [
"Chemistry",
"Biology"
] | 3,973 | [
"Behavior",
"Developmental biology",
"Reproduction",
"Senescence",
"Cellular processes",
"Metabolism"
] |
65,611,367 | https://en.wikipedia.org/wiki/Square%20%28tool%29 | A square is a tool used for marking and referencing a 90° angle, though mitre squares are used for 45° angles. Squares see common use in woodworking, metalworking, construction and technical drawing. Some squares incorporate a scale for measuring distances (a ruler) or for calculating angles.
Terminology
Many squares are made of two parts, a stock and a straight blade or tongue. The stock is usually thicker than the blade, with the blade being fixed into or onto the stock. The blade typically has parallel edges. The stock is usually held against the edge of a workpiece or drawing board and the tongue is then used as a straight edge for making a mark, or as a reference to check the accuracy of an angle.
History
Wooden try squares have survived from Ancient Egypt and Ancient Rome and can be seen in art from the time. From the 18th century squares began to be manufactured in factories, prior to that they were typically made from wood and were often made by the tradesmen themselves. Some woodworkers continue to make their own squares.
Types of square
There are a number of different types of square used for a variety of different industries and purposes:
Accuracy
Different industries and applications have different requirements for the accuracy of squares. Some squares are manufactured to meet regulated standards of accuracy, such as British Standards BS 939:2007 for engineering squares, and BS 3322 for try squares.
A square can become inaccurate over time through common use and abuse, such as the edges becoming worn or the square being dropped or mistreated. The materials, most notably wood, can also vary with changes in temperature and humidity. Squares can be checked for accuracy against a known reference, such as a square or piece of machinery that is known to be accurate or against a cylindrical square. A bright light or feeler gauges can be used to check for gaps between the square and the object being referenced.
Through symmetry squares can also be checked against themselves. One method for L-shaped squares (illustrated) is to hold the square against a reliable known straight edge, a line is struck using a marking knife or sharp pencil, the square is then flipped over and from the same point another line is struck. If the square is accurate there should only be a single line visible.
There are a number of methods for correcting an inaccurate square by hand. For example, wooden blades can be corrected using a hand plane and sandpaper, while metal blades can be corrected using a file, emery cloth, or sandpaper. Framing squares can be adjusted using a hammer and a punch.
Symbolism
The square is incorporated into the most common Freemasonry symbol, the Square and Compasses. Historically squares have also been used by woodworkers, such as joiners and carpenters, as symbols in signs and heraldry to represent their trade. The square as a symbol is also seen in artistic representations of the Christian saints Thomas the Apostle and James the Less.
References
Woodworking measuring instruments
Metalworking measuring instruments
Dimensional instruments
Woodworking hand tools
Technical drawing tools | Square (tool) | [
"Physics",
"Mathematics"
] | 608 | [
"Quantity",
"Dimensional instruments",
"Physical quantities",
"Size"
] |
65,611,509 | https://en.wikipedia.org/wiki/List%20of%20plant%20genus%20names%20with%20etymologies%20%28L%E2%80%93P%29 | Since the first printing of Carl Linnaeus's Species Plantarum in 1753, plants have been assigned one epithet or name for their species and one name for their genus, a grouping of related species. Many of these plants are listed in Stearn's Dictionary of Plant Names for Gardeners. William Stearn (1911–2001) was one of the pre-eminent British botanists of the 20th century: a Librarian of the Royal Horticultural Society, a president of the Linnean Society and the original drafter of the International Code of Nomenclature for Cultivated Plants.
The first column below contains seed-bearing genera from Stearn and other sources as listed, excluding those names that no longer appear in more modern works, such as Plants of the World by Maarten J. M. Christenhusz (lead author), Michael F. Fay and Mark W. Chase. Plants of the World is also used for the family and order classification for each genus. The second column gives a meaning or derivation of the word, such as a language of origin. The last two columns indicate additional citations.
Key
Latin: = derived from Latin (otherwise Greek, except as noted)
Ba = listed in Ross Bayton's The Gardener's Botanical
Bu = listed in Lotte Burkhardt's Index of Eponymic Plant Names
CS = listed in both Allen Coombes's The A to Z of Plant Names and Stearn's Dictionary of Plant Names for Gardeners
G = listed in David Gledhill's The Names of Plants
St = listed in Stearn's Dictionary of Plant Names for Gardeners
Genera
See also
Glossary of botanical terms
List of Greek and Latin roots in English
List of Latin and Greek words commonly used in systematic names
List of plant genera named for people: A–C, D–J, K–P, Q–Z
List of plant family names with etymologies
Notes
Citations
References
See http://creativecommons.org/licenses/by/4.0/ for license.
Further reading
Available online at the Perseus Digital Library.
Available online at the Perseus Digital Library.
Systematic
Greek words and phrases
Systematic
Systematic
Taxonomy (biology)
Glossaries of biology
Gardening lists
Genus names with etymologies (L-P)
Etymologies, L
Wikipedia glossaries using tables | List of plant genus names with etymologies (L–P) | [
"Biology"
] | 477 | [
"Lists of plants",
"Plants",
"Lists of biota",
"Taxonomy (biology)",
"Taxonomic lists",
"Glossaries of biology"
] |
65,612,920 | https://en.wikipedia.org/wiki/Freedom%20on%20the%20Net | Freedom on the Net is an annual report providing analytical reports and numerical ratings regarding the state of Internet freedom for countries worldwide, published by the American non-profit research and advocacy group Freedom House. The countries surveyed represent a sample with a broad range of geographical diversity and levels of economic development, as well as varying levels of political and media freedom.
Methodology
The surveys ask a set of questions designed to measure each country's level of Internet and digital media freedom, as well as the access and openness of other digital means of transmitting information, particularly mobile phones and text messaging services. Results are presented for three areas: p.31
Obstacles to Access: infrastructural and economic barriers to access; governmental efforts to block specific applications or technologies; legal and ownership control over internet and mobile phone access providers.
Limits on Content: filtering and blocking of websites; other forms of censorship and self-censorship; manipulation of content; the diversity of online news media; and usage of digital media for social and political activism.
Violations of User Rights: legal protections and restrictions on online activity; surveillance and limits on privacy; and repercussions for online activity, such as legal prosecution, imprisonment, physical attacks, or other forms of harassment.
The results from the three areas are combined into a total score for a country (from 100 for "Most Free" to 0 for "Least Free") and countries are rated as "Free" (100 to 70), "Partly Free" (69 to 40), or "Not Free" (39 to 0) based on the totals. p.31
Results
Starting in 2009 Freedom House has produced eleven editions of the report.
There was no report in 2010. The reports generally cover the period from June through May.
2020 results
Comparison with Other Datasets
Several other organizations measure internet freedom, such as the V-Dem Institute, Access Now, and the OpenNet Initiative. V-Dem's Digital Society project measures a range of questions related to internet censorship, misinformation online, and internet shutdowns using surveys of experts. Access Now maintains an annual list of internet shutdowns, throttling, and blockages as part of the #KeepItOn project. The OpenNet Initiative formerly kept data on internet censorship of particular websites. Freedom on the Net's report covers a range of concepts that the other datasets do not, such as new legislation passed, but lacks the country coverage of other datasets.
Expert surveys such as Freedom House and V-Dem have been found to be more prone to false positives (they are more likely to find uncorroborated instances of censorship). While remote sensing such as the kind done by Access Now and OpenNet Initiative are more likely to be prone to false negatives (they may miss some instances of real censorship).
The Millennium Challenge Corporation used the Key Internet Controls portion of the Freedom on the Net report to inform its country selection process until 2020 when this report was replaced with data on internet shutdowns from Access Now.
References
Digital rights
Works about the Internet | Freedom on the Net | [
"Technology"
] | 623 | [
"Works about the Internet",
"Works about computing"
] |
44,190,409 | https://en.wikipedia.org/wiki/N%20cap | The term N cap (N-cap, Ncap) describes an amino acid in a particular position within a protein or polypeptide. The N cap residue of an alpha helix is the first amino acid residue at the N terminus of the helix. More precisely, it is defined as the first residue (i) whose CO group is hydrogen-bonded to the NH group of residue i+4 (or sometimes residue i+3). Because of this it is sometimes also described as the residue prior to the helix.
Capping motifs are those often found at the N cap. Asx turns, ST turns, and asx motifs are often found at such situations, with the asx or serine or threonine residue at the N cap.
The C cap is the corresponding amino acid residue at the other end of the helix
References
Amino acids | N cap | [
"Chemistry"
] | 174 | [
"Amino acids",
"Biomolecules by chemical classification"
] |
44,190,450 | https://en.wikipedia.org/wiki/C%20cap | The term C cap (C-cap, Ccap) describes an amino acid in a particular position within a protein or polypeptide. The C cap residue of an alpha helix is the last amino acid residue at the C terminus of the helix. More precisely, it is defined as the last residue (i) whose NH group is hydrogen-bonded to the CO group of residue i-4 (or sometimes residue i-3). Because of this it is sometimes also described as the residue following the helix.
Certain motifs occur commonly at or around the C cap, notably the Schellman loop and the niche (protein structural motif).
The N cap is the corresponding amino acid residue at the other end of the helix
References
Amino acids | C cap | [
"Chemistry"
] | 151 | [
"Amino acids",
"Biomolecules by chemical classification"
] |
44,190,891 | https://en.wikipedia.org/wiki/Quadrupole%20formula | In general relativity, the quadrupole formula describes the rate at which gravitational waves are emitted from a system of masses based on the change of the (mass) quadrupole moment. The formula reads
where is the spatial part of the trace reversed perturbation of the metric, i.e. the gravitational wave. is the gravitational constant, the speed of light in vacuum, and is the mass quadrupole moment.
It is useful to express the gravitational wave strain in the transverse traceless gauge, which is given by a similar formula where is the traceless part of the mass quadrupole moment.
The total energy (luminosity) carried away by gravitational waves is
The formula was first obtained by Albert Einstein in 1918. After a long history of debate on its physical correctness, observations of energy loss due to gravitational radiation in the Hulse–Taylor binary discovered in 1974 confirmed the result, with agreement up to 0.2 percent (by 2005).
See also
Multipole radiation
Birkhoff's theorem (relativity)
PSR J0737−3039
References
General relativity
Gravitational-wave astronomy
Equations of physics
Albert Einstein | Quadrupole formula | [
"Physics",
"Astronomy",
"Mathematics"
] | 232 | [
"Equations of physics",
"Mathematical objects",
"Astrophysics",
"General relativity",
"Equations",
"Theory of relativity",
"Gravitational-wave astronomy",
"Astronomical sub-disciplines"
] |
44,191,380 | https://en.wikipedia.org/wiki/User%20onboarding | User onboarding is the process of improving an individual's requirements and success with a product or service. This term is often used in reference to software products, and it can be done in a manual or automated way. It is the process through which new software is designed such that new users are provided and acquire the necessary knowledge, skills, and behaviors in order to become “up and running” and effective users of website, app, or software service.
The term originates from the human resources term, onboarding, that refers to the mechanism through which new employees acquire the necessary knowledge, skills, and behaviors in order to become effective organizational members.
The goal of user onboarding is to get the users to understand the key principles at the heart of the product and to show them how it will improve their lives. If it can make the point of the product clear and easy to understand the first time a user tries it, have a better chance of gaining excited and engaged customers.
Offering a free trial is an example of how you can implement user onboarding. If someone is able to see how the product is useful and exciting to them within a free trial period, it can take them from being a user to a consumer—willing to invest in order to continue their experience.
Onboarding techniques
Leveraging the right user onboarding techniques based on the specific requirements can be extremely beneficial for businesses.
Below are different user onboarding techniques and their classifications.
Single sign-on or social login - Ease the login and add less friction with SSO or Social Login.
Interactive tutorials, Walkthrough - In-application tutorials that help to onboard new users, highlight features in your application, and also reflect your value proposition faster and easier.
Beacons, tooltips - Raise visitors attention by adding beacon to any element on the web page.
Checklists - Leverage gamification effect (see Zeigarnik effect) and provide a clear step-by-step on-boarding flow.
Coach screens - Opening screens stitched together that appear mostly after the splash screen moves away.
Training videos - Context-based training videos
References
Software architecture
Software engineering terminology | User onboarding | [
"Technology",
"Engineering"
] | 434 | [
"Software engineering",
"Computing terminology",
"Software engineering stubs",
"Software engineering terminology"
] |
44,191,777 | https://en.wikipedia.org/wiki/Comparison%20of%20free%20blog%20hosting%20services | A number of websites offer free hosting of blogs. The services they offer are compared below. (This list is limited to services that have their own Wikipedia article.)
Free blog hosting services
See also
Comparison of file hosting services
Comparison of online backup services
References
Blog hosting services
Companies' terms of service | Comparison of free blog hosting services | [
"Technology"
] | 60 | [
"Online services comparisons",
"Computing comparisons"
] |
44,192,006 | https://en.wikipedia.org/wiki/Lieb%E2%80%93Oxford%20inequality | In quantum chemistry and physics, the Lieb–Oxford inequality provides a lower bound for the indirect part of the Coulomb energy of a quantum mechanical system. It is named after Elliott H. Lieb and Stephen Oxford.
The inequality is of importance for density functional theory and plays a role in the proof of stability of matter.
Introduction
In classical physics, one can calculate the Coulomb energy of a configuration of charged particles in the following way. First, calculate the charge density , where is a function of the coordinates . Second, calculate the Coulomb energy by integrating:
In other words, for each pair of points and , this expression calculates the energy related to the fact that the charge at is attracted to or repelled from the charge at . The factor of corrects for double-counting the pairs of points.
In quantum mechanics, it is also possible to calculate a charge density , which is a function of . More specifically, is defined as the expectation value of charge density at each point. But in this case, the above formula for Coulomb energy is not correct, due to exchange and correlation effects. The above, classical formula for Coulomb energy is then called the "direct" part of Coulomb energy. To get the actual Coulomb energy, it is necessary to add a correction term, called the "indirect" part of Coulomb energy. The Lieb–Oxford inequality concerns this indirect part. It is relevant in density functional theory, where the expectation value ρ plays a central role.
Statement of the inequality
For a quantum mechanical system of particles, each with charge , the -particle density is denoted by
The function is only assumed to be non-negative and normalized. Thus the following applies to particles with any "statistics". For example, if the system is described by a normalised square integrable -particle wave function
then
More generally, in the case of particles with spin having spin states per particle and with corresponding wave function
the -particle density is given by
Alternatively, if the system is described by a density matrix , then is the diagonal
The electrostatic energy of the system is defined as
For , the single particle charge density is given by
and the direct part of the Coulomb energy of the system of particles is defined as the electrostatic energy associated with the charge density , i.e.
The Lieb–Oxford inequality states that the difference between the true energy and its semiclassical approximation is bounded from below as
where is a constant independent of the particle number . is referred to as the indirect part of the Coulomb energy and in density functional theory more commonly as the exchange plus correlation energy. A similar bound exists if the particles have different charges . No upper bound is possible for .
The optimal constant
While the original proof yielded the constant , Lieb and Oxford managed to refine this result to . Later, the same method of proof was used to further improve the constant to . It is only recently that the constant was decreased to . With these constants the inequality holds for any particle number .
The constant can be further improved if the particle number is restricted. In the case of a single particle the Coulomb energy vanishes, , and the smallest possible constant can be computed explicitly as . The corresponding variational equation for the optimal is the Lane–Emden equation of order 3. For two particles () it is known that the smallest possible constant satisfies . In general it can be proved that the optimal constants increase with the number of particles, i.e. , and converge in the limit of large to the best constant in the inequality (). Any lower bound on the optimal constant for fixed particle number is also a lower bound on the optimal constant . The best numerical lower bound was obtained for where . This bound has been obtained by considering an exponential density. For the same particle number a uniform density gives .
The largest proved lower bound on the best constant is , which was first proven by Cotar and Petrache. The same lower bound was later obtained in using a uniform electron gas, melted in the neighborhood of its surface, by Lewin, Lieb & Seiringer. Hence, to summarise, the best known bounds for are .
The Dirac constant
Historically, the first approximation of the indirect part of the Coulomb energy in terms of the single particle charge density was given by Paul Dirac in 1930 for fermions. The wave function under consideration is
With the aim of evoking perturbation theory, one considers the eigenfunctions of the Laplacian in a large cubic box of volume and sets
where forms an orthonormal basis of . The allowed values of are with . For large , , and fixed , the indirect part of the Coulomb energy can be computed to be
with .
This result can be compared to the lower bound (). In contrast to Dirac's approximation the Lieb–Oxford inequality does not include the number of spin states on the right-hand side. The dependence on in Dirac's formula is a consequence of his specific choice of wave functions and not a general feature.
Generalisations
The constant in () can be made smaller at the price of adding another term to the right-hand side. By including a term that involves the gradient of a power of the single particle charge density , the constant can be improved to . Thus, for a uniform density system .
References
Further reading
Inequalities
Density functional theory | Lieb–Oxford inequality | [
"Physics",
"Chemistry",
"Mathematics"
] | 1,111 | [
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"Density functional theory",
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"Mathematical relations",
"Inequalities (mathematics)",
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44,192,232 | https://en.wikipedia.org/wiki/Rim%20lichen | Rim lichen is a common name for lichens in either the genus Lecanora or the genus Squamarina
References | Rim lichen | [
"Biology"
] | 28 | [
"Set index articles on fungus common names",
"Set index articles on organisms"
] |
44,192,353 | https://en.wikipedia.org/wiki/Sprinklr | Sprinklr is an American software company that develops a software as a service (SaaS) customer experience management (CXM) platform. The company's software, also called Sprinklr, combines different applications for social media marketing, social advertising, content management, collaboration, employee advocacy, customer care, social media research, and social media monitoring.
Sprinklr was founded in 2009 by technology executive Ragy Thomas. On June 23, 2021, the company went public on the New York Stock Exchange under the symbol CXM.
History
Sprinklr was founded in 2009 by Ragy Thomas, a technology marketing executive previously with email marketing company Bigfoot International. Thomas initially funded the company himself, with servers operating out of the basement of his home. The company's name came from the metaphor of a brand carefully watering its social media presence. Early customers included Cisco, Dell and Virgin America.
In March 2015, the company announced the launch of its Experience Cloud platform, a way for companies to manage interactions over 23 social media channels and websites. The company expanded from social media management to customer experience management in April 2017, with the launch of new products for its Experience Cloud platform, ranging from social listening tools to content marketing. In October 2017, the company added eight additional products integrated with Experience Cloud.
In April 2018, Sprinklr released artificial intelligence (AI) capabilities called Sprinklr Intuition, allowing the automatic collection and analysis of social media data.
As of October 2018, it was reported that the company had over 1,500 customers.
In May 2019, the company released Product Insights, an AI capability that automatically categorizes customer comments across social media and review sites about product feedback related to design, packaging, performance or features.
As of December 2019, the company reported over 1,500 employees, and 25 offices in 15 countries, located across North and South America, Europe and Asia-Pacific.
In 2020, Sprinklr offered case tracking services to the Kerala government in India, as part of an app to assist with managing the COVID-19 outbreak. In April 2020, the opposition party to the government accused the company of compromising patient data related to COVID-19 patients, and criticized the services for being awarded without following proper procedures. The company denied the charges, claiming that the data used in its platform is owned and controlled by the government and stored in India, in compliance with India's data privacy regulations. The government confirmed with the Kerala High Court through an affidavit that the Covid-related data was managed by Kerala's Centre for Development of Imaging Technology (C-DIT) in the Amazon Web Services cloud, and that no Sprinklr employees had any access to the data.
On June 23, 2021, Sprinklr began trading as a public company on the New York Stock Exchange under the symbol CXM.
Funding
In March 2012, the company received its first outside funding.
In May 2014, the company announced a $40 million funding round, bringing it to a $500 million valuation.
In March 2015, a $46 million series E funding round gave the company a value of $1.17 billion.
In July 2016, the company announced a $105 million funding round for a valuation of $1.8 billion.
In September 2020, Sprinklr raised $200 million from private-equity firm Hellman & Friedman in a deal that valued the customer experience management company at $2.7 billion.
Partnerships and sponsorships
Beginning in 2017, Sprinklr partnered with Forbes to create their "Most Influential CMO" lists, sourcing data from LinkedIn.
In April 2020, Sprinklr became the first advertising partner of TikTok, and expanded the partnership to organic content in May 2022.
In 2022, Sprinklr announced partnerships with Amazon Connect and Twilio, integrating its customer care products.
During the 2022 season, Sprinklr became a sponsor for the BWT F1 Alpine team.
Acquisition strategy
Sprinklr uses its funding to acquire smaller firms that have the tools Sprinklr wants to build itself. To facilitate integration, Sprinklr discards the purchased technology and has the acquired company's employees develop a native Sprinklr version of the software.
Acquisitions
In March 2014, Sprinklr acquired Dachis Group, adding abilities for employee advocacy, competitive intelligence, social business consulting services, and content marketing.
In August 2014, Sprinklr acquired TBG Digital, one of Facebook's largest ad buying clients, to improve its paid social advertising capability. Later in September, Sprinklr acquired brand advocacy company Branderati.
In April 2015, Sprinklr acquired Get Satisfaction, a customer community software platform to bolster its customer care product offering.
In June 2015, Sprinklr bought text analytics vendor NewBrand. In November 2015, the company acquired data segmentation firm Booshaka.
In April 2016, the company acquired social analytics startup Postano.
In December 2019, the company acquired the social advertising business from ad management company Nanigans.
References
Marketing companies established in 2009
Companies listed on the New York Stock Exchange
Search engine optimization
Software companies based in New York City
Social software
2021 initial public offerings
Software companies established in 2009
2009 establishments in New York City | Sprinklr | [
"Technology"
] | 1,089 | [
"Mobile content",
"Social software"
] |
44,192,410 | https://en.wikipedia.org/wiki/Lecanorine%20lichen | A lichen has lecanorine fruiting body parts if they are shaped like a plate with a ring around them, and that ring is made of tissue similar to the main non-fruiting body part of the lichen. The name comes from the name of the lichen genus Lecanora, whose members have such apothecia. If a lichen has lecanorine apothecia, the lichen itself is sometimes described as being lecanorine.
References
Lichenology | Lecanorine lichen | [
"Biology"
] | 102 | [
"Lichenology"
] |
44,192,956 | https://en.wikipedia.org/wiki/Pigment%20Red%20190 | Pigment Red 190 (C.I. 71140), also called Vat Red 29, is a synthetic organic compound that is used both as a pigment and as a vat dye. Although structurally a derivative of perylene, it is produced from acenaphthene.
It is usually applied for cotton fabric, jig dyeing, PVA and silk dyeing, still may processed into organic pigment.
References
Perylene dyes
Vat dyes
Imides | Pigment Red 190 | [
"Chemistry"
] | 99 | [
"Functional groups",
"Organic compounds",
"Imides",
"Organic compound stubs",
"Organic chemistry stubs"
] |
44,192,996 | https://en.wikipedia.org/wiki/Villa%20Bologna | Villa Bologna is a Maltese stately home, in the village of Attard in the central district of Malta. Built in opulent Baroque style, Villa Bologna has been called "the most beautiful 18th century country house to be built for a Maltese family" and "of similar grandeur to the finest palaces on the island".
Villa Bologna is as interesting for its history as it is remarkable for its architecture and gardens which, after the neighbouring San Anton Gardens, is the largest historic gardens in Malta. Once the seat of the Counts della Catena, Villa Bologna is now held by the great-grandson of the 6th count Gerald Strickland, 1st Baron Strickland.
Built during the rule of the Order of St. John of Jerusalem and expanded during the British colonial period, Villa Bologna was central in the artistic, cultural, social and political history of Malta. It is a Grade 1 scheduled building and is a national monument.
History
Villa Bologna was constructed, by Fabrizio Grech, in 1745 as a gift for his daughter Maria Teresa Grech on her marriage to Nicholas Perdicomati Bologna, later the 2nd Count della Catena. Fabrizio Grech was both sindaco of the Maltese Università and uditore, or advisor, to Grand Master Pinto. By virtue of these offices, especially of the latter one, Grech became an immensely wealthy and influential man. A story, much repeated but never substantiated, has it that he was provoked into building a residence of surpassing beauty and magnificence for his daughter by aspersions cast by his new in-laws on his social standing. This is unlikely. In the first place, the Perdicomati Bolognas were no family of ancient title; the first count was ennobled barely three months before his son married Maria Teresa Grech. Secondly, a man like Grech, whose influence over the Grand Master was such that the Grand Master had full trust in him, who was known for his overbearing manner and who commanded resources sufficient to build a mansion on the scale of Villa Bologna, was hardly likely to feel inferior to a count minted barely three months before the marriage alliance between their families. There is also some evidence to indicate that Grech and his daughter's father-in-law were very close associates indeed. Whatever the case may be, Nicholas Perdicomati Bologna and Maria Teresa Grech were married on 25 April 1745 and they were given this "fabulous villa" as a wedding present. Nicholas was succeeded by his daughter Maria Giovanna Perdicomati Bologna (the 3rd Countess) and, later, by his youngest daughter Angela Perdicomati Bologna (the 4th Countess). Angela married Baron Sciberras and the title, together with entail and the Villa passed on to their son Nicholas Sciberras Bologna in 1798. After the death without issue of Nicholas Sciberras Bologna, 5th Count della Catena, in 1875, protracted litigation between the putative heirs of the 5th Count was resolved in 1882 when the Judicial Committee of the Privy Council awarded the title and lands, including Villa Bologna to Gerald Strickland, the great-grandson of Angela Perdicomati Bologna and her husband Baron Sciberras.
Gerald Strickland, now Gerald Bologna Strickland 6th Count della Catena, later also raised to the peerage of the United Kingdom as Baron Strickland of Sizergh, was to usher in a new age for Villa Bologna. The 6th Count, more usually known as Lord Strickland, was probably the most politically influential native of Malta in its history. The son of Walter Strickland, a British naval officer of a family of landholding gentry descended in part from the Plantagenet and Norman kings through Edward III, Lord Strickland had a spectacular political career and held many political offices in both Malta and around the British Empire. At one point he even held simultaneously the office of Leader of the Opposition in Malta as well as that of Conservative MP for Lancaster in the UK's House of Commons. Later he was elected Head of Ministry (office equivalent to that of Prime Minister) of Malta as well. By that time, he had resigned his seat from the British House of Commons to take up a seat in the House of Lords upon his elevation to the peerage as Baron Strickland of Sizergh. He was also appointed governor of a number of British colonies, the only colonial ever to hold such an office. Such was the stature of the man that he was acclaimed as "Pater Patriae" (Father of his Fatherland/Father of his Country) by the people of Malta, a title harking back to Republican and Imperial Rome and one of great resonance in the Latin culture of Malta. Lord Strickland also made two highly advantageous marriages. In 1890, Lord Strickland married Lady Edeline Sackville-West, the daughter of the 7th Earl de la Warr. Lady Edeline gave him eight children, including the Hon. Mary Constance Strickland, the Hon. Cecilia Victoria Strickland and the Hon. Mabel Edeline Strickland. Of the two boys born to Lord Strickland, neither survived infancy. During these years, Lord Strickland held numerous governorships of British colonies around the British Empire and, while the family was absent from Villa Bologna, he generously allowed an order of religious nuns to occupy the villa until the family should return to Malta. Lady Edeline died in 1918. In 1926, Lord Strickland married Margaret Hulton, daughter of the newspaper magnate Edward Hulton. It was Lady Strickland who was to modernise Villa Bologna and, together with her friend Count Giuseppe Teuma Castelletti, she extended the gardens far beyond their original limits, raised the walls of the property and decorated them with crenels. She added turrets, planted hundreds of trees and many exotic species, and laid out fountains and ponds of unique character and beauty. If Fabrizio Grech had built a fabulous villa, it was Lady Strickland who was to transform it into a horticultural paradise.
In 1940, Lord Strickland died and, for the first time since its construction, the ownership of Villa Bologna was estranged from the Catena title. The title passed on to the son of Lord Strickland's eldest daughter, the Hon. Mary Constance Horneyold Strickland while Villa Bologna passed on to Gerald Edmund Hubert de Trafford(1929-2015), the eldest son of the Hon. Cecilia Victoria Strickland and her husband Captain Hubert de Trafford. In 1971, Gerald married Helena Catherina Charlotte Hallo (b. 1945) and they had two children – Dr Aloisia Cecilia Mary de Trafford (b. 1973) and Jasper Peter Paul Sybrand de Trafford (b. 1975).
After the death of Gerald in 2015, his son, Jasper, who had been managing the estate since 2009, inherited Villa Bologna and is now the current holder of the Villa, the seventh of his line to hold it. Jasper married Fleur Cecilia Kate de Trafford (b. 1978) and they had two sons, Cosmo Benedict Randolphus (b. 2011) and Montague Francis Humphrey (b. 2013).
Design
The architect of Villa Bologna is unknown but an attempt has been made to attribute this design to Domenico Cachia, capomastro della Fondazione Manoel. This is because the design of Selmun Palace, which is very similar in places to that of Villa Bologna, too has been attributed to Cachia. However, this attribution is unproven and tentative at best. Current research indicates that Andrea Belli, who was an architect involved in the reconstruction of the Auberge de Castille between 1741 and 1744), may be responsible for Villa Bologna. This possibility may appear remote but a certain similarity between the Auberge de Castille and Villa Bologna, as well as the dates of Castille's reconstruction (1741-1744), just a year prior to the construction of Villa Bologna, support this hypothesis. Moreover, Andrea Belli's brother was a colleague of Fabrizio Grech and this same brother appears to have colluded substantially with Fabrizio Grech and the Perdicomati Bolognas in the Bologna-Testaferrata case. These close links between the principal characters of the story and Andrea Belli offer strong circumstantial evidence that Belli was, indeed, the architect of Villa Bologna. Confirmation, however, requires further research. Nonetheless, this evidence linking one of the most imposing, majestic and lavish palaces ever erected by the Knights of Malta with Villa Bologna gives some insight into the character of Fabrizio Grech. It also speaks volumes about the extent of his influence and his wealth.
The villa is constructed on a basic quadrilateral plan, the footprint of which is approximately 440 metres2. Nonetheless, there are numerous wings and extensions to the main building, some of which even antedate the main building itself. These include an older villa, an old farmhouse and a side-wing stretching from the south-west corner of the main villa to the Nymphaeum. There were an aviary and a mill room on one side of this fountain and an aviary and a tower on the other side. Another extension along the west façade was constructed by Lady Strickland. This is a mezzanine that allowed for the extension of the main dining room and the addition of some staff accommodation. The villa is built in the Baroque style, with some discernible Neo-Classical influences here and there.
Exterior
The front (east) façade is a triumph of Mediterranean Baroque architecture, featuring elaborate expressions of the Baroque idiom and including a large balcony that runs along the entire length of the front façade. The idiom is grandiloquent but the proportions are so excellent that the viewer is not overwhelmed by the monumental size of the villa. The south façade is also in the Baroque style but is much more subdued. There are no sculpted façades on the west and north sides. One element of note is that the windows on the upper storey are Neo-Classical in style, an apparent anomaly on a building so otherwise resolutely Baroque. This may be due to the changing fashions of the years in which the villa was built. A mezzanine was added along the west façade by Lady Strickland in the 1920s. The style of this mezzanine is classical and very different from the rest of the villa since it was designed to blend with the New Garden rather than with the Villa. This side does have the addition of mullioned windows graced by extraordinarily beautiful stained glass bearing the heraldic devices of the Bologna and the Strickland families. The stained glass was damaged during the war when a bomb fell in the grounds of the Villa and it was repaired in Florence after the war. To the right of the large Nymphaeum is a building called the Pavilion that served as the workshop where Lord Strickland, a keen amateur carpenter and engineer, practised his favourite hobbies. The Pavilion was originally an aviary and mill room and it was the mill room that came to serve as a workshop for Lord Strickland. The aviary was converted into accommodation in the 1970s. A 16th-century villa which is now a wing of the main building runs along the north façade from the Dolphin Garden to the wall overlooking the street. In all, the area of the entire building may run to twice the size of the main Villa.
Interior
The main door of the villa opens onto a great hall with rooms at each of the four corners. These are the sitting room, the study, the Pink Room and the dining room, which was extended by Lady Strickland beyond the original width of the west façade. At the far end of this dining room are the mullioned windows with the stained glass bearing the coats of arms of the Bologna and the Strickland families. In these windows are set two doors leading out into the New Garden. To the north of the dining room lies the kitchen. Up a stately staircase, there is a ballroom. This floor is built on the same plan as the ground floor and around the ballroom are four large bedrooms. One of these served as Lord Strickland's bedroom and has a large dressing room and a marble bathroom that were added on by him in the 1920s. The west side of the villa has now been divided into apartments. These once housed the serving staff. This wing predates the main villa and the decor of these rooms is far more subdued than those of the rest of the villa.
Shelter
In 1942, at the height of World War II, when the bombing of Malta was at its most intense, it was felt necessary to put in a shelter under the house. In fact, the shelter that was eventually constructed is one of the largest private shelters in Malta. The entrance was through the cellar of the main house and this too was adorned with stairs of marble. This staircase led down into the principal room of the shelter that had once served as the villa's main well at the time of the original construction. At the time that the shelter was dug out, this main room served to store the boilers that provided the villa's central heating and it also included a shaft for coal. The shelter has numerous rooms and an area serving as an infirmary or delivery room. This room has plastered walls and a tiled floor. It was also equipped with electricity. This shelter was no idle precaution. The villa is very close to Ta’ Qali where the military airport for the defence of Malta during World II was located. The villa itself was bombed and a German pilot parachuted into the garden after he bailed out of his burning aircraft. The shelter is open to the public and access is through a spiral staircase that was originally the shelter's emergency exit.
Garden
Villa Bologna is a palatial country house typical of the Mediterranean Baroque. Though regally splendid in its own right, it is through its gardens that it acquires a character that is absolutely unique in the annals of Maltese architecture. The gardens of Villa Bologna were laid out in two phases. The original garden, better known as the Baroque Garden, dates back to the original construction in 1745. This garden was laid out in the traditional style with a symmetrical layout and citrus trees throughout. Later on, lawns were added and exotic trees were planted. This garden is remarkable for its nymphaea, one large and one small, the larger of which is said to be one of the best examples of the use of rocaille in Malta. To the east of the larger Nymphaeum is a Baroque gateway framing the larger Nymphaeum as one looks through it from the lawn. After his term as governor expired, Lord Strickland brought saplings back from Australia and planted the Grevillea and a couple of other Australian trees in the Baroque Garden. Lady Strickland continued this trend of adding interesting exotic species to the garden and the part of the orange orchard closest to the villa slowly became a minor arboretum in which the orange trees were replaced with large exotic trees (the Grevillea, Jacaranda, etc.) Some exotic trees were also planted around the border of this garden, including what is probably Malta's first and oldest avocado tree as well as a specimen of Pimenta dioica. As these trees matured, the citrus in that area suffered. However, the shade provided created a pleasant area for entertaining so this part of the Baroque Garden was adorned with Maltese paving stones. In the 1950s, the garden was further modified and two lawns were put down in the centre of the garden with a row of balustrades separating the paved area from the lawn. Despite these modifications this part of the garden retains its Baroque character and is dominated by the Baroque statuary and Nympahaea.
The New Garden was laid out by Lady Strickland after she married Lord Strickland in 1926. An Englishwoman, Lady Strickland came from a culture that reveres gardens and, being extremely wealthy in her own right, she was able to indulge her passion for gardens by letting her imagination run loose on the grounds of Villa Bologna. Thus, assisted by her friend, Count Giuseppe Teuma Castelletti, she laid out large gardens along the western side of the villa. The New Garden was most likely inspired by Villa Frere and La Mortola in Italy. She greatly increased the acreage of the estate, bringing the total up to around 7.3 acres and she added a line of cypresses recalling the famous gardens of La Mortola on the Italian Riviera. Moreover, she planted Malta's first grapefruit and avocado trees, an exotic vegetable garden, including asparagus, and cherry trees as well as tangerines. Furthermore, she increased the height of the property's walls and adorned them with crenels as well as hexagonal towers. Among the trees she added are carob trees, Norfolk pines and palm trees. Perhaps the most spectacular additions she put in were the Dolphin Pond and the Sunken Pond, two ponds that, for beauty and character, have no equal in Malta. Finally, she installed a watering system of irrigation channels made of stone and supplied by an underwater reservoir.
Such was the scale of her work in the garden that in the 1930s she was employing 16 gardeners working full-time 10 hours a day, 6 days a week. The New Garden also contains a small cottage and a water tower.
Baroque Garden
The Baroque Garden is the old garden of the villa, laid out at the time of the construction of the villa in the 18th century. These gardens are typical of the Baroque in Italy at that time, with a symmetrical layout set around cobbled pavements with pillars bearing stone pots of all kinds. The garden was originally planted with all sorts of citrus trees, especially orange trees. Later on, especially during the days of Lord Strickland, lawns were added and exotic trees, including palm trees, as well as other types of fruit trees were planted. Flowering shrubs and creepers were likewise added to this garden. Of particular interest are the large Nymphaeum and the small one, as well as the Baroque Gateway that frames the large Nymphaeum as one looks through it towards the west.
The Nymphaeum
Two of the most outstanding features in the Baroque Garden are the larger Nymphaeum and the Baroque Gateway. The larger Nymphaeum is a fountain built in the 18th century in the Rococo style and is one of the best uses of rocaille in Malta. The rocaille of this Nymphaeum includes gagazza, coral-like material, and real seashells. Rusticated columns frame the niches and panels while figures drawn from Classical mythology, or personifications of nature, fill the fountain. There are also dolphins serving as waterspouts and Nereids serving as caryatids. On top of the fountain are busts of the four seasons. Over the fountain is a carving of the face of Neptune and the main panels contained statues of Bacchus and Pan. However, these two statues were damaged when they fell into the fountain and are currently awaiting restoration. All these figures are carved in the style of the Rococo. This Nymphaeum is in an enclosed garden beyond the Baroque Gateway in the Baroque Garden.
The Baroque Gateway
The Baroque Gateway is less complex but no less imposing. On the left side of the gate is a statue of Cleopatra over which is the reclined figure of the god of river Nile. On the other side of the gate is a statue of Mark Antony and above this statue is the reclined figure of the god of the river Tiber. The gateway, beautiful as it is, comes into its own when one looks through it towards the west, upon which it appears to frame the large Nymphaeum to ravishing effect.
Dolphin Pond
One of the most visually alluring spaces in the New Garden is the Dolphin Pond. This is a pond in the middle of which is the statue of a boy embracing a swan from whose beak springs a fountain of water. In each corner of the pond, a toad spouts water into the pond. Soaring on columns around the pond are four arches meeting on the corners of a rectangle just above the pond. On each arch is a stone dolphin carved in the Baroque style. These dolphins once spouted water too but this feature is currently being restored. The pond is in the middle of a space divided into lawns separated by a cobbled pavement and surrounded by a hedge of salvia. Majestic palm trees once held sway across the lawn but were wiped out by the Red Palm Weevil (Rhynchophorus ferrugineus) which swept Malta between 2005 and 2010. However, since then, other palm trees have been planted to replace the ones lost to the Red Palm Weevil but they will take some years to reach maturity. One noteworthy feature of this area is its exceptional proportions. Such is the mathematical precision of these proportions that despite the size of this area, it does not appear to dwarf any element in it and it appears to be just right in size rather than excessive in any way.
The Sunken Pond
Up a flight of stairs leading west from the Dolphin Pond is an area far smaller in size but just as attractive to visitors. Past the stairs and turning left through a pergola, one runs into a pond of unusual character. This is the Sunken Pond, so called because it is sunk deep into the limestone pavers. On the north side of the pond, there is a balustrade leading down to the pond by means of a flight of stairs both sides of the pond. There is a walkway around the pond on the same level. There are stone pots for cactus plants and other flora around the perimeter of the pond, and a stone pelican, which serves as a fountain, on the south side. Growing in the corners are water rushes. On the main level, flanking the pond, are two semi-circular stone benches shaded by false pepper (Schinus Molle) trees. On the south side of the pond, there is a lofty dovecote which once housed a sizeable colony of pigeons. The small size of the Sunken Pond and the surrounding area, together with its unusual character, impart a feeling of intimacy and magic to this area such that it strikes the fancy of many visitors to the villa. In fact, it is extremely common for visitors to call the Sunken Pond their favourite part of the whole estate.
Pottery
At the far end of the estate were the old stables that the Hon. Cecilia de Trafford transformed into a pottery for the employment of local artists and the production of authentic Maltese potterware. The origin of the pottery harks back to a pottery run by family friend Count Giuseppe Teuma Castelletti before World War II. During the war, the Count stored his stock in the cellar at Villa Bologna, which was lucky indeed since his pottery, then at a now forgotten location at Ta’ Qali, was hit by a bomb. Then, in 1951, it occurred to Cecilia, Gerald's mother, to set up a pottery in the old stables to continue the work of Count Giuseppe Teuma Castelletti.
At that time, it was called "Malta Industries Association" because it formed part of a group of industries, including weaving, set up by Cecilia. Indeed, these were the first industries set up for Maltese workers at a time when the Maltese economy was diversifying from solely one based on servicing the British forces. Eventually, the pottery acquired its own identity and the name of "Ceramika Seracina", which has now been changed to "Ceramika Maltija". A key player responsible for the setting up of the Pottery was Charles Bone, a prominent artist and potter from Puttenham, Surrey. In 1951, the 25-year-old Charles was asked by Cecilia to come to Malta to start up the pottery, which was then intended to offer employment to women. This he did, together with his wife, the sculptor Sheila Mitchell, during a period of six weeks in Malta in 1952. At that time absolutely no glazed pottery was made in Malta at all, so the pottery became Malta's first of its kind. The pottery started from scratch so its management and artists had a hard time developing
an artistic style that was distinguishably of a Maltese character, mainly because Malta had been occupied for many centuries so its art was dominated by influences of a foreign character. Naturally, this hindered the evolution of an endemic Maltese style. Nonetheless, the pottery employed artists like Carmel Gerada, who applied the patterns of Maltese lace to the ceramics, and Aldo Cremona, who developed the scroll pattern that adorns so much of the pottery's work even today.
Most of the ceramic work produced by the pottery from its first years of operation has always been slip cast white earthenware. The pottery specialises in the production of items such as dining sets, stylised representations of Mediterranean life, images of saints, the renowned dolphin and pineapple lamps, and large plates decorated with scenes from local life. The colours used are the fresh and bright colours of Malta and the designs themselves, namely fish, fruit, scroll patterns and lace sgraffito, are quirky and full of life. All the products of the pottery are made and painted by hand so each piece is completely unique.
Today
Villa Bologna remains the residence of the de Traffords, the latest generation of the descendants of Fabrizio Grech, the man who built it. Like all other such estates, it has faced varying fortunes over the centuries. Shortly after the death of Lady Strickland, the woman who transformed the fortunes of the estate in the interwar period, the political and economic turmoil of the decolonisation period in Maltese history hit the villa and the family fortunes hard. More recently, the family is reviving the villa by turning it into a working estate. The gardens are now wholly accessible to the public and the villa may be booked for corporate and private events of all sorts. As with all such properties, the villa is a popular venue for filming. The family's interest in gardening has not wavered since the days of Lady Strickland. Various ventures of horticulture are taking place, with methods of gardening and farming that are as natural as possible. The produce of the villa is on sale to the public from the grounds of the property. The house itself, and the collections, are not yet available to the public since much restoration has to be carried out before they are made thus available. However, the World War II shelter is freely accessible for anyone taking the garden tour. As always, the family is a dedicated sponsor of philanthropic events, and the villa hosts many such events throughout the year.
Many things make Villa Bologna unique but it is the constant residence of the family that breathes life and soul into it. The majesty of the house and the fabulous character of the gardens are brought to life by the work the family puts into maintaining and developing it for the purpose of turning it into a major socio-cultural centre in Maltese life. Above all, it is thanks to the eclectic origins of the family that owns the villa that what once a typical Mediterranean country house in the style of the Italian Baroque has been transformed into what is essentially an English stately home under the Mediterranean sun.
The villa is listed on the National Inventory of the Cultural Property of the Maltese Islands.
Notable residents
Lord Strickland
Edeline Sackville-West
Mary Constance Strickland
Cecilia Victoria Strickland
Mabel Strickland
Notable visitors
Fra Andrew Bertie
Lord Mountbatten
Queen Elizabeth II
David Niven
Noël Coward
Raymond de Trafford
Julian Huxley
Dominic Mintoff
Desmond Morris
See also
List of Baroque residences
References
Bibliography
Attard Montalto, John, A Belligerent Vicar-General and the Bologna Dynasty, The Sunday Times of Malta, May 2, 2004, p. 41.
Ciappara, Frans, The Roman Inquisition in Enlightened Malta, Malta : Pubblikazzjonijiet Indipendenza, 2000.
Gauci, Charles, The Genealogy of the Noble Families of Malta, Volume 1, Gulf Publishing, Valletta 1981.
Jackewicz Johnston, Shirley, Splendor of Malta, Rizzoli International Publications, New York 2001.
London Gazette, The: https://www.thegazette.co.uk.
Mahoney, Leonard, A History of Maltese Architecture from Ancient Times up to 1800, Veritas Press, Malta 1988.
MEPA: http://www.mepa.org.mt/.
Pine, L. G., (ed.), Burke’s Peerage, 100th Edition, London 1953.
Property and Construction Supplement, Times of Malta, Wednesday, January 15, 2014.
Sant Fournier: Sant Fournier.
Smith, Harrison and Koster, Adrianus, Lord Strickland Servant of the Crown, Volume 1, Progress Press, Valletta 1984.
Smith, Harrison and Koster, Adrianus, Lord Strickland Servant of the Crown, Volume 2, Progress Press, Valletta 1986.
Villa Bologna: http://www.villabologna.com/.
External links
Attard
Baroque palaces in Malta
Bologna
Landscape architecture
Landscape design history
Sackville family
Tourism in Malta
Tourist attractions in Malta
Limestone buildings in Malta
National Inventory of the Cultural Property of the Maltese Islands | Villa Bologna | [
"Engineering"
] | 6,018 | [
"Landscape architecture",
"Architecture"
] |
44,193,635 | https://en.wikipedia.org/wiki/Old-Growth%20Forest%20Network | The Old-Growth Forest Network is an American 501(c)(3) non-profit organization whose mission is to protect old-growth forests from logging by identifying them throughout the United States.
Purpose
The Old-Growth Forest Network's vision is a national network of forests where people are able to experience the beauty and integrity of nature. To achieve its vision, the organization strives to create a network of forests across the U.S.—with one in each county—that are not logged and are open to visitors. In the Eastern United States, more than 99 percent of old-growth forests have been cleared for agricultural or developmental purposes, or have been replaced by second-growth forests. The organization's goal is to ensure that some forests are set aside and protected, allowing them to recover their old-growth characteristics. These "future old-growth forests" will provide opportunities for future generations across the country to experience native forests in their mature diversity and complexity.
History
The Old-Growth Forest Network was founded by Joan Maloof, Salisbury University, Maryland, now Executive Director of the organization. She spends her time lecturing, writing, visiting forests, assisting private landowners, and supporting local groups trying to protect community forests from development. The work of the Old-Growth Forest Network is also supported by staff and volunteers, including County Coordinators who act as liaisons to the managers of the dedicated forests in the network.
Maloof began as a scientist studying the natural workings of the planet—the systems that enable the trees and flowers and animals to subsist on their own with no help from humans. When she looked for natural places to study, she found that almost everything had been affected by humans. She also became aware that the oldest forests—some of the most natural and biologically diverse places on earth—were being logged and converted into managed forests—monoculture tree farms. Maloof was not opposed to harvesting trees for board and fiber, but as an ecologist, she knew that sacrificing biodiversity came hand in hand with not only sacrificing beauty but also toppling the network that keeps the balance of the planet.
Maloof realized that as a scientist she could do little to ensure that at least some of the forests would be left alone, but that as a writer she could share what other scientists had learned about the importance of ancient forests. She wrote Teaching the Trees: Lessons from the Forest. The first chapter describes a visit to an eastern old-growth forest, a forest that had never been logged. Her readers, few of whom had ever witnessed an old-growth forest, wanted to know how they could visit one. There were a few left, but very little information existed about how to find them. That led to a second book: Among the Ancients: Adventures in the Eastern Old-Growth Forests, reflections on one old forest in each of the twenty-six Eastern states—with directions. Maloof went on to author two more books: Nature's Temples: The Complex World of Old-Growth Forests, and The Living Forest: A Visual Journey Into the Heart of the Woods, a coffee-table book featuring the photography of Robert Llewellyn.
In her journeys to these forests, and through the forestry literature, Maloof learned that very few original forests have not been logged or otherwise disturbed—less than 1% remains in the East, and 5% in the West. Thus began Maloof's transition from writer to founder of an organization that would identify and help protect one forest in each county of the US where forests could grow and let people know where they were located. Her plan was to help stop the destruction of what old-growth remained, help some forests recover, and enable more Americans to experience an old forest.
In 2011 she left her university position and started working full-time to establish the Old-Growth Forest Network. With the help of her board, Maloof started building the network and educating others about it. In that first year, twenty forests were formally added to the Network and 600 supporters signed up. Maloof gave twenty-three lectures—including talks at Longwood Gardens, the US Botanical Garden, Cornell University and Penn State University.
As of July 15, 2021, the Network had 138 inductees in 25 states, toward the goal of having at least one forest in every county in the United States that can sustain a forest—estimated to be 2,370 counties. As of March 22, 2023, the Network had 189 inductee forests in 32 states.
Organizational strategy
For the network to be within reach of all Americans, the organization intends to identify one forest that will be left forever wild within each county where forests naturally grow. Of the 3,140 counties in the US, it is estimated that about 75%, or 2,370 will support forests. Many of these counties already contain public forests so only a single one would need to be chosen and officially recognized as part of the network. In many counties it will be already protected Federal land which becomes recognized in the network, such as a National Forest or Fish and Wildlife land. In other places, it may be a State Forest that is recognized. In some counties that have no State or Federal lands, the county or city itself may have some property that could become part of the network. The next level of landowners to be considered for voluntarily joining the network are likely to be nonprofit organizations such as land trusts or The Nature Conservancy. In the less common situations where there are no public lands and no nonprofit organization lands which can be included in the network, a county may appeal to a private donor or apply for federal grant funds, perhaps with the assistance of an organization such as The Conservation Fund.
The Old-Growth Forest Network's strategy is to identify candidate forests, ensure that they are publicly accessible and protected forever from logging, and recognize them as part of the network. Once dedicated, the forests are listed and publicized on the network's website. The organization believes that building the Network in this way will take very little financial investment, and that the preservation of over two thousand undisturbed, accessible forests will have a positive effect on both the humans and the wildlife in the U.S.
Community forests and private landowners
Local activists contact the Old-Growth Forest Network to help protect community forests threatened with development. The organization advocates for forest preservation and assists local protection efforts where possible. Community forests that may not be as large, ecologically diverse, or as stringently protected can be inducted into the Old-Growth Forest Network's Community Forest program.
Many of the oldest forests in the United States are privately owned. The organization advises private landowners about their forests and helps them realize their preservation goals. Private forest owners who commit to protecting their land in perpetuity through mechanisms such as a "Forever Wild" conservation easement (meaning it will never be logged) may also receive recognition by the Old-Growth Forest Network's Private Forest designation.
References
External links
Green Tree Services - Residential & Commercial Tree Services
Adrian Higgins, Oct. 24, 2017. An ecologist speaks for the silent giants: Old-growth trees. Washington Post.
New England Forests, Mar 25, 2018 (video). The Lost Forests of New England.
She started a movement that speaks for the forests: An interview with Joan Maloof, founder of the Old-Growth Forest Network.
Bob Yearick, May 2013. Saving Sacred Woodlands. Out and About Magazine.
Forest conservation organizations
Network
Charities based in Maryland
Nature conservation organizations based in the United States | Old-Growth Forest Network | [
"Biology"
] | 1,523 | [
"Old-growth forests",
"Ecosystems"
] |
44,194,851 | https://en.wikipedia.org/wiki/Beta-sandwich | Beta-sandwich or β-sandwich domains consisting of 80 to 350 amino acids occur commonly in proteins. They are characterized by two opposing antiparallel beta sheets (β-sheets). The number of strands found in such domains may differ from one protein to another. β-sandwich domains are subdivided in a variety of different folds. The immunoglobulin-type fold found in antibodies (Ig-fold) consists of a sandwich arrangement of 7-9 antiparallel β-strands arranged in two β-sheets with a Greek-key topology. The Greek-key topology is also found in Human Transthyretin. The jelly-roll topology is found in carbohydrate binding proteins such as concanavalin A and various lectins, in the collagen binding domain of Staphylococcus aureus Adhesin and in modules that bind fibronectin as found in Tenascin (Third Fibronectin Type III Repeat). The L-type lectin domain is a variation of the jelly roll fold. The C2 domain in its typical version (PKC-C2) is a β-sandwich composed of 8 beta-strands (β-strands).
References
Protein structural motifs | Beta-sandwich | [
"Chemistry",
"Biology"
] | 256 | [
"Biochemistry stubs",
"Protein structural motifs",
"Protein stubs",
"Protein classification"
] |
44,195,454 | https://en.wikipedia.org/wiki/Cinnamosma%20fragrans | Cinnamosma fragrans is a species of flowering plant in the family Canellaceae. It is endemic to Madagascar, where it is commonly known as saro.
Description
Cinnamosma fragrans is a shrub or medium-sized tree, growing up to 8 meters tall. It can be distinguished from the other species of Cinnamosma by its oval-shaped fruits; the fruits of C. macrocarpa and C. madagascariensis are globose.
Range and habitat
Cinnamosma fragrans native to the provinces of Antsiranana and Mahajanga in northern and western Madagascar. It is widespread in dry deciduous forests between sea level and 500 meters elevation. It typically grows on unconsolidated sands, sandstone, or limestone substrates. There are dense populations in Melaky, and Diana regions. The species' estimated extent of occurrence (EOO) is 151,773 km2.
Specimens collected from higher-elevation subhumid forests are misidentified specimens of C. madagascariensis or C. macrocarpa.
Uses
Cinnamosma fragrans is a traditional medicinal plant used to treat respiratory problems and gastrointestinal infections. The leaves of the plant are harvested in Mahajanga Province to make essential oil for national and international trade.
References
Canellaceae
Endemic flora of Madagascar
Taxa named by Henri Ernest Baillon
Flora of the Madagascar dry deciduous forests
Essential oils | Cinnamosma fragrans | [
"Chemistry"
] | 292 | [
"Essential oils",
"Natural products"
] |
44,195,492 | https://en.wikipedia.org/wiki/March%20of%20the%20Machines | March of the Machines: Why the New Race of Robots Will Rule the World (1997, hardcover), published in paperback as March of the Machines: The Breakthrough in Artificial Intelligence (2004), is a book by Kevin Warwick. It presents an overview of robotics and artificial intelligence (AI), often focusing on anecdotes of Warwick's own work, and then imagines future scenarios. In particular, Warwick finds it likely that such AIs will become smart enough to replace humans, and humans may be unable to stop them.
Contents
The book has a conversational style, with little technical detail. Warwick proposes that because machines will become more intelligent than humans, machine takeover is all but inevitable. The drive to automate is fueled by economic incentives. Even if machines start out without intentions to take over, those that self-modify in a direction toward a "will to survive" are more likely to resist being turned off. Arms races will likely create ever-increasing pressure for greater autonomy by robotic warfare systems, and this pressure would be hard to curtail. Machines have a number of advantages over human minds, including the ability to expand practically without limit and to spread into space where humans can't reach. "All the signs are that we will rapidly become merely an insignificant historical dot" (p. 301).
Reception
John Durant in the New Statesman cautions against Warwick's apparent anthropomorphism: In one problematic example passage, Warwick opines that the Deep Blue computer had deliberately "let Kasparov win the overall (1996) series, having shown him in the first game who was really the better player". Durant states that "There's rather a lot of this sort of thing in March of the Machines, and it's not clear how seriously it's intended to be taken." Durant also disagreed with Warwick's thesis, stating that present-day computers "are not threats to us, but rather expressions of our power: we use the machines; they don't use us." Durant also wonders why, "If Warwick's thesis about impending world robot-domination is correct", Warwick continues to undertake cybernetic research.
Don Braben begins his review of Warwick's book by stating that "Specialists love to share dire predictions of the future, which stem from limited perspectives." Braben also states that, despite the centrality of intelligence to the thesis, Warwick fails to adequately pin down the slippery concept.
In Human Physiology, Medvedev and Aldasheva dispute Warwick's contention that machines will become superior to humans on the grounds that "machines are man-made human organs", i.e., they extend what humans do. Moreover, if machines were to rebel against humans, humans could make use of other machines to combat the rebels. If AIs were created, humans would program them to align with human goals, and while some AIs might go awry, this would not be so different from the situation of human maniacs. All told, they consider Warwick's predictions of robot rebellion "grossly exaggerated".
The blurb for the 1997 edition stated in part "Recent breakthroughs in cybernetics mean that robots already exist with the brain power of insects. Within five years, robots will exist with the brain power of cats. In ten to 50 years, robots will exist that are more intelligent than humans." Revising in 2014, Martin Robbins of Vice news quotes Warwick's predictions of robot abilities as an example of "Extravagant claims" that "have been damaging the reputation of our soon-to-be robot overlords for decades now".
Notes
Robotics
Robots
Cybernetics
Fictional technology
Futurology books
2004 books | March of the Machines | [
"Physics",
"Technology",
"Engineering"
] | 758 | [
"Machines",
"Robots",
"Automation",
"Physical systems",
"Robotics"
] |
44,197,493 | https://en.wikipedia.org/wiki/Seaweed%20collecting | Seaweed collecting is the process of collecting, drying, and pressing seaweed. It became popular as a pastime in the Victorian era and remains a hobby today.
History of seaweed collecting
Collecting seaweed can be traced back to at least the 17th century with the pressings found in Hans Sloane's Herbarium.
The pastime became increasingly popular during the Victorian Era, where it played to the burgeoning interest in natural history and collection in general. It was especially fashionable with young women, as it allowed a greater level of personal freedom. Indeed, it was so in-style that, as a young girl, Queen Victoria created her own seaweed album. The materials needed for the hobby became readily available at seaside shops. These activities also afforded women the opportunity to display their understanding and appreciation of the natural world.
Anna Atkins, thought to be the first female photographer, published the first book using photographs as illustrations. This was Photographs of British Algae: Cyanotype Impressions and contained pictures of seaweed.
The actions of some of the collectors earned them recognition and admiration from their male, professional counterparts.
These Victorian collections form valuable historical resources for morphological studies and from which genomic DNA can be extracted.
Seaweed collecting equipment
In his 1881 book, A.B. Hervey recommended the following equipment for collecting and pressing seaweed.
See also
History of phycology
Phycology
References
External links
Digitised seaweed collections at the Brooklyn Museum
Phycology
Collecting | Seaweed collecting | [
"Biology"
] | 296 | [
"Algae",
"Phycology"
] |
44,198,564 | https://en.wikipedia.org/wiki/Lighting%20as%20a%20service | Lighting as a service (LaaS), also known as light as a service, is a service-based business model in which light service is charged on a subscription basis rather than via a one-time payment. It is managed by third parties, more precisely, by specialized service providers and may include light design, financing, installation, maintenance and other services. The model enables customers to outsource lighting aspects of their business over a set time.
In opposition to an operating lease, the LaaS provider does not transfer the ownership of a product but maintains the ownership of the equipment throughout the duration of the subscription contract. This makes it an environmentally friendly business approach allowing an extended product life with several lifecycles. The LaaS model has become more common in commercial installations of LED lights, specifically in retrofitting buildings and outdoor facilities, with the prior aim of reducing installation costs. Since nowadays lighting design has to consider aspects such as safety and health at work, environmental performance, energy consumption and durability of the products, the model is continuously gaining more and more importance for company structures. Refitting and maintaining buildings with energy efficient lighting systems by means of a LaaS provider enables it to be operated more economically. Light vendors have used an LaaS strategy in selling value-added services such as Internet-connected lighting and energy management.
History
Over the years, the lighting industry has faced a major disruption due to the shift in demand from conventional light sources to energy-efficient lighting. Especially in the commercial sector, this industrial change has caused a higher demand in long-life LED products, which come along with lower energy consumption and improved physical robustness. While light bulbs have to be replaced approximately every year or two, LED products last around 20 years. The idea of Lighting as a Service was invented in response to business demand in order to decrease the costs and boost the efficiency of energy without any investment from the end users side. All of this is achieved by the help of light control systems and the Internet of Things.
The concept of selling lighting as a service was developed by Thomas Rau in collaboration with Philips throughout the first "Pay per Lux" project. Customers would only pay for the amount of light they use. The idea originated when Thomas Rau equipped the office of RAU Architects in Amsterdam. Instead of purchasing lighting infrastructure that comes with high costs and the need to be replaced after some time, he applied the model of light as a service to furnish the building with lighting. LED installations along with a sensor and controller system to minimize energy use were provided by Philips, who maintained the ownership of the set-up. RAU Architects on the other hand benefited from the entire maintenance service.
Value proposition
Lighting as a service offering include indoor and outdoor service types and usually are demanded by end users from the commercial, municipal or industrial sectors. LaaS supplies client companies with efficient lighting technology and in the most cases undertakes associated services including project management, product delivery and installation as well as maintenance.
Pros
Since no upfront investment has to be done, the subscription to LaaS offers comes with less engagement of personal resources. This subsequently has a positive impact on the reduction of risks and costs for the end user. Furthermore, modern lighting technology solutions, such as intelligent LED light systems or daylight and shading technology, used by LaaS vendors result in a lower energy consumption, thus lower energy costs as well as the reduction of carbon emissions and a healthier lighting in general. The light supplier as an expert in the light industry remains accountable for monitoring and maintaining the lighting systems (including replacements), upholding new legal requirements and also deals with recycling issues.
Cons
The subscription to LaaS offerings does not involve the acquisition of the lighting product itself and makes the provider retain the ownership. Throughout the duration of the contract the client is bound to its provider which, depending upon the contract arrangement and funding model, can be set up to long durations.
Market
Development
The global lighting as a service market is growing rapidly, welcoming more and more lighting companies, IT integrators and facility management service providers trying to capture the new market by the means of refining their business models to "as a service" offerings, but also through mergers, collaborations and partnerships. In the face of the current global situation, smart building technology vendors are currently launching lighting propositions to improve the infection control of buildings in order to kill bacteria and viruses from surfaces with safe lighting rays such as ultraviolet light.
Keyplayers
In terms of geographical distribution, the LaaS market is categorized into seven main regions: North and Latin America, Eastern Europe, Western Europe, Asia-Pacific, Japan and the Middle East and Africa. North America constitutes the largest market for LaaS, closely followed by Western and Eastern Europe, which is expected to witness the fastest growth rate in 2018-2025. This change is attributed to the widespread adoption of LaaS in Germany and the UK. Global key players are Cooper Industries Inc. (US), SIB Lighting (US), Cree Inc. (US), Digital Lumens Inc. (US), Lutron Electronics Company Inc. (US), General Electric Lighting (US), Itelecom USA (US), Future Energy Solutions (US & UK), Igor Inc. (UK), Legrand (France), Koninklijke Philips N.V. (Netherlands), Eaton Corporation (Ireland), Urban Volt (Ireland), Zumtobel Group (Austria), Osram Ag (Germany), Deutsche Lichtmiete (Germany) and RCG Lighthouse (Latvia). The leading position of North America in the LaaS market is mostly due to the significant development regarding electricity consumption in the United States. The government implementations of certain energy standards help reduce its carbon emission as well as the energy consumption rate, mostly through usage of energy efficient light bulbs. These have to be either LED or fluorescent. The adoption of LED lighting on the other hand is catering to the market growth of LaaS models. The most prominent lighting renovation project is the Bristol-Myers Squibb in Lawrenceville. The prior aim of the project is to harvest daylight through control systems and thus reduce the energy consumption for office spaces. In the meantime LaaS companies in Europe come up with different lighting solutions such as for example the launch of emergency lighting for big open-plan areas by Eaton. Furthermore, cooperations between light vendors and LaaS providers such as the alliance between Zumtobel and Deutsche Lichtmiete lead to improved full-service business models, allowing to broaden the application segments.
See also
as a service
References
service
Architectural_lighting_design
Building_automation
Energy-saving_lighting | Lighting as a service | [
"Engineering"
] | 1,354 | [
"Building engineering",
"Building automation",
"Automation"
] |
44,198,675 | https://en.wikipedia.org/wiki/Binomial%20sum%20variance%20inequality | The binomial sum variance inequality states that the variance of the sum of binomially distributed random variables will always be less than or equal to the variance of a binomial variable with the same n and p parameters. In probability theory and statistics, the sum of independent binomial random variables is itself a binomial random variable if all the component variables share the same success probability. If success probabilities differ, the probability distribution of the sum is not binomial. The lack of uniformity in success probabilities across independent trials leads to a smaller variance. and is a special case of a more general theorem involving the expected value of convex functions. In some statistical applications, the standard binomial variance estimator can be used even if the component probabilities differ, though with a variance estimate that has an upward bias.
Inequality statement
Consider the sum, Z, of two independent binomial random variables, X ~ B(m0, p0) and Y ~ B(m1, p1), where Z = X + Y. Then, the variance of Z is less than or equal to its variance under the assumption that p0 = p1 = , that is, if Z had a binomial distribution with the success probability equal to the average of X and Y 's probabilities. Symbolically, .
Proof
We wish to prove that
We will prove this inequality by finding an expression for Var(Z) and substituting it on the left-hand side, then showing that the inequality always holds.
If Z has a binomial distribution with parameters n and p, then the expected value of Z is given by E[Z] = np and the variance of Z is given by Var[Z] = np(1 – p). Letting n = m0 + m1 and substituting E[Z] for np gives
The random variables X and Y are independent, so the variance of the sum is equal to the sum of the variances, that is
In order to prove the theorem, it is therefore sufficient to prove that
Substituting E[X] + E[Y] for E[Z] gives
Multiplying out the brackets and subtracting E[X] + E[Y] from both sides yields
Multiplying out the brackets yields
Subtracting E[X] and E[Y] from both sides and reversing the inequality gives
Expanding the right-hand side gives
Multiplying by yields
Deducting the right-hand side gives the relation
or equivalently
The square of a real number is always greater than or equal to zero, so this is true for all independent binomial distributions that X and Y could take. This is sufficient to prove the theorem.
Although this proof was developed for the sum of two variables, it is easily generalized to greater than two. Additionally, if the individual success probabilities are known, then the variance is known to take the form
where is the average probability and . This expression also implies that the variance is always less than that of the binomial distribution with , because the standard expression for the variance is decreased by ns2, a positive number.
Applications
The inequality can be useful in the context of multiple testing, where many statistical hypothesis tests are conducted within a particular study. Each test can be treated as a Bernoulli variable with a success probability p. Consider the total number of positive tests as a random variable denoted by S. This quantity is important in the estimation of false discovery rates (FDR), which quantify uncertainty in the test results. If the null hypothesis is true for some tests and the alternative hypothesis is true for other tests, then success probabilities are likely to differ between these two groups. However, the variance inequality theorem states that if the tests are independent, the variance of S will be no greater than it would be under a binomial distribution.
References
Probability theorems
Theorems in statistics
Statistical inequalities | Binomial sum variance inequality | [
"Mathematics"
] | 806 | [
"Theorems in statistics",
"Statistical inequalities",
"Theorems in probability theory",
"Inequalities (mathematics)",
"Mathematical problems",
"Mathematical theorems"
] |
44,199,210 | https://en.wikipedia.org/wiki/List%20of%20Android%20apps%20by%20Google | This is a list of mobile apps developed by Google for its Android operating system. All of these apps are available for free from the Google Play Store, although some may be incompatible with certain devices (even though they may still function from an APK file) and some apps are only available on Pixel and/or Nexus devices. Some of these apps may be pre-installed on some devices, depending upon the device manufacturer and the version of Android. A few, such as Gboard, are not supported on older versions of Android.
Active
Accessibility Scanner
Action Blocks
Adaptive Connectivity Services (formerly Connectivity Health Services)
AI Wallpapers
Android Accessibility Suite
Android Auto
Android Auto Receiver
Android AICore
Android Device Policy
Android System Intelligence
Android System WebView
Android System WebView Beta
Android System WebView Canary
Android System WebView Dev
Android TV Core Services
Android TV Home
Android TV Launcher
Android TV Remote Service
Backdrop Daydream
Blogger
Calculator
Cardboard
Carrier Services
Chrome Remote Desktop
Chromecast Built-in
Clock
Cloud
Compose Material Catalog
Contacts
Creative Preview
Cross-Device Services
Crowdsource
Data Restore Tool
Data Transfer Tool
Device Health Services
Device Lock Controller
Device Utility
Digital Wellbeing
Dive Case Connector for Pixel
Emoji Workshop Wallpaper
Fast Pair Validator
Files by Google
Fitbit
Aira Air Update
Fitbit ECG App
Fitbit Ace
Jelly Jam
Gallery
Gboard
GIF Keyboard by Tenor
Gmail
Gmail Go
GnssLogger App
Google
Google App for Android TV
Google Go
Google Admin (formerly Google Settings)
Google Ads
Google AIY Projects
Google Analytics
Google Arts & Culture
Google Arts & Culture VR
Google Assistant
Google Assistant Go
Google Assistant – In the Car
Google Authenticator
Google Automotive App Host
Google Calendar
Google Chat (formerly Hangouts Chat)
Google Chrome
Chrome Beta
Chrome Canary
Chrome Dev
GameSnacks
Google Classroom
Google Cloud Search (formerly Google Springboard)
Google Connectivity Services
Google Docs
Google Drive
Google Earth
Google Family Link
Family Link Manager
Family Link Parental Controls
Google Fi Wireless
Google Fiber
Google Find My Device
Google Fit
Google Gemini
Google Health Studies
Google Home (formerly Chromecast and Google Cast)
Google Keep
Google Lens
Google Local Services Ads
Google Maps
Google Maps Go
Navigation for Google Maps Go
Google Meet (formerly Hangouts Meet and Google Duo)
Google Messages (formerly Messenger, Android Messages, and Messages)
Google News
Google One
Google Opinion Rewards
Google Partner Setup
Google Pay
Google Photos
Google Pixel Buds
Google Pixel Watch
Google Pixel Watch Faces
Google Pixel Watch Services
Google Play Books (formerly Google eBookstore)
Google Play Console
Google Play Games
Google Play Protect Service
Google Play Services
Google Play Services for AR (formerly ARCore)
Google Santa Tracker
Google Sheets
Google Slides
Google Support Services
Google Tasks
Google Translate
Google TV (formerly Google Movies and Google Play Movies & TV)
Google TV Ambient Mode
Google TV Home
Google Voice
Google Wallet (formerly Android Pay and Google Pay)
Google Wi-Fi Provisioner
Health Connect
Live Channels
Live Transcribe & Sound Notifications (formerly Live Transcribe)
Looker Mobile
Looker Studio
Lookout
Magnifier
Motion Sense Bridge
Online Insights Study
Personal Safety
Phone by Google
Photomath
PhotoScan by Google Photos
Pixel Camera
Pixel Camera Services
Pixel Launcher
Pixel Live Wallpaper
Pixel Stand
Pixel Thermometer
Pixel Tips
Pixel Troubleshooting
Play Billing Lab
Private Compute Services
Project Activate
Project Baseline
Project Relate
Read Along by Google (formerly Bolo)
Reading Mode
Recorder
Screenwise Meter
Security Hub
Settings Services (formerly Settings Suggestions)
SIM Manager
Snapseed
Socratic by Google
Sound Amplifier
Sounds
Speech Recognition & Synthesis
Switch Access
System Parental Controls
Toontastic 3D
TV Setup
Voice Access
VPN by Google
Wallpapers
Waze
Wear OS by Google (formerly Android Wear)
Wear OS System UI
Wear OS Media Sessions
Weather
WifiNanScan App
WifiRttScan App
WifiRttLocator App
YouTube
YouTube for Android TV
YouTube Create
YouTube Kids
YouTube Kids for Android TV
YouTube Music
YouTube Music for Android TV
YouTube Music for Chromebook
YouTube Studio (formerly YouTube Creator Studio)
YouTube TV
YouTube TV for Android TV
Discontinued
Abstracted Motion – Mural in A
AdSense (merged with Google Ads)
AdWords Express (merged with the main Google Ads app)
AI Test Kitchen
Android Auto for Phone Screens (merged with the Google Assistant)
Androidify
Android Dev Summit
Android Things Toolkit
Android TV Data Saver
ARCore Elements
Audio Factory
Beacon Tools
Cameos on Google
Cardboard Camera
Cardboard Design Lab
Cloud Next
Cloud Print
Currents (formerly Google+ for G Suite)
Datally (formerly Triangle)
Daydream
Daydream Elements
Daydream Keyboard
DoubleClick for Publishers (merged with AdWords)
Google Expeditions (merged with Google Arts & Culture)
Fabby
FameBit
Fiber TV
Flutter Gallery
Google+
Google AdMob
Google Allo
Google Apps Device Policy
Google Body
Google BrailleBack
Google Cantonese Input
Google Cast Receiver
Google Clips
Google Currents (merged with Google Play Newsstand)
Google Duo (merged with Google Meet)
Google Finance
Google Gesture Search
Google Goggles (merged with Google Lens)
Google Handwriting Input
Google Indic Keyboard
Hangouts (merged with Google Chat and Google Meet)
Google Japanese Input
Google Korean Input
Google Listen (merged with Google Play Music and Google Reader)
Google Maps Navigation (merged with the main Google Maps app)
Grasshopper
Jamboard
Material Gallery
Measure
MyGlass
Google My Business
Google My Maps
Google News & Weather (merged with Google News)
Google Now Launcher (merged with the Google app)
Google Pay Send (formerly Google Wallet) (merged with Google Pay)
Google PDF Viewer (merged with Google Drive)
Google Pinyin Input
Google Play Magazines (merged with Google Play Newsstand)
Google Play Music (formerly Music Beta and Google Music) (merged with YouTube Music and Google Podcasts)
Google Play Newsstand (merged with Google News)
Google Podcasts (merged with YouTube Music)
Google Primer
Google Reader
Google Shopping (formerly Google Shopping Express and Google Express)
Google Spaces
Google Station Onsite
Google TalkBack (merged with Android Accessibility Suite)
Google Trips
Google Voice (merged with Google Hangouts)
Google Voice Search (merged with Google Now)
Google VR Services
Google Wifi (merged with Google Home)
Google Zhuyin Input
Hangouts Dialer
Inbox by Gmail (merged with the main Gmail app)
Intersection Explorer
Ivy Big Number Calculator
Jacquard by Google
Jump Inspector
Motion Stills
MyTracks (merged with Google Fit)
Nest (merged with the Google Home app)
Notable Women
One Today by Google
Pixel Ambient Services
Playbook for Developers
Playground (formerly AR Stickers)
Quickoffice
Scoreboard
Science Journal
Soli Sandbox
Spotlight Stories
Stadia
Google Street View (merged with the main Google Maps app)
Tango (merged with ARCore)
Task Mate
Trusted Contacts (merged with Google Maps)
VR180
YouTube Gaming (merged with the main YouTube app)
YouTube Go
YouTube Remote (merged with the main YouTube app)
YouTube VR
See also
List of Google products
Google Mobile Services
References
Android (operating system) software
Google software
Lists of mobile apps
Google lists | List of Android apps by Google | [
"Technology"
] | 1,377 | [
"Computing-related lists",
"Google lists"
] |
49,031,124 | https://en.wikipedia.org/wiki/Nitrokey | Nitrokey is an open-source USB key used to enable the secure encryption and signing of data. The secret keys are always stored inside the Nitrokey which protects against malware (such as computer viruses) and attackers. A user-chosen PIN and a tamper-proof smart card protect the Nitrokey in case of loss and theft. The hardware and software of Nitrokey are open-source. The free software and open hardware enables independent parties to verify the security of the device. Nitrokey is supported on Microsoft Windows, macOS, Linux, and BSD.
History
In 2008 Jan Suhr, Rudolf Böddeker, and another friend were travelling and found themselves looking to use encrypted emails in internet cafés, which meant the secret keys had to remain secure against computer viruses. Some proprietary USB dongles existed at the time, but lacked in certain ways. Consequently, they established as an open source project - Crypto Stick - in August 2008 which grew to become Nitrokey. It was a spare-time project of the founders to develop a hardware solution to enable the secure usage of email encryption. The first version of the Crypto Stick was released on 27 December 2009. In late 2014, the founders decided to professionalize the project, which was renamed Nitrokey. Nitrokey's firmware was audited by German cybersecurity firm Cure53 in May 2015, and its hardware was audited by the same company in August 2015. The first four Nitrokey models became available on 18 September 2015.
Technical features
Several Nitrokey models exist which each support different standards. For reference S/MIME is an email encryption standard popular with businesses while OpenPGP can be used to encrypt emails and also certificates used to login to servers with OpenVPN or OpenSSH. One-time passwords are similar to TANs and used as a secondary security measure in addition to ordinary passwords. Nitrokey supports the HMAC-based One-time Password Algorithm (HOTP, RFC 4226) and Time-based One-time Password Algorithm (TOTP, RFC 6238), which are compatible with Google Authenticator.
The Nitrokey Storage product has the same features as the Nitrokey Pro 2 and additionally contains an encrypted mass storage.
Characteristics
Nitrokey's devices store secret keys internally. As with earlier technologies including the trusted platform module they are not readable on demand. This reduces the likelihood of a private key being accidentally leaked which is a risk with software-based public key cryptography. The keys stored in this way are also not known to the manufacturer. Supported algorithms include AES-256 and RSA with key lengths of up to 2048 bits or 4096 bits depending on the model.
For accounts that accept Nitrokey credentials, a user-chosen PIN can be used to protect these against unauthorized access in case of loss or theft. However, loss of or damage to a Nitrokey (which is designed to last for 5-10 years) can also prevent the key's owner from being able to access his or her accounts. To guard against this, it is possible to generate keys in software so that they may be securely backed up to the best of the user's ability before they undergo a one-way transfer to the secure storage of a Nitrokey.
Nitrokey is published as open source software and free software which ensures a wide range of cross platform support including Microsoft Windows, macOS, Linux, and BSD. It is designed to be usable with popular software such as Microsoft Outlook, Mozilla Thunderbird, and OpenSSH. It is also open hardware to enable independent reviews of the source code and hardware layout and to ensure the absence of back doors and other security flaws.
Philosophy
Nitrokey's developers believe that proprietary systems cannot provide strong security and that security systems need to be open source. For instance there have been cases in which the NSA has intercepted security devices being shipped and implanted backdoors into them. In 2011 RSA was hacked and secret keys of securID tokens were stolen which allowed hackers to circumvent their authentication. As revealed in 2010, many FIPS 140-2 Level 2 certified USB storage devices from various manufacturers could easily be cracked by using a default password. Nitrokey, because of being open source and because of its transparency, wants to provide highly secure system and avoid security issues which its proprietary rivals are facing. Nitrokey's mission is to provide the best open source security key to protect the digital lives of its users.
References
External links
Authentication methods
Computer access control
Open hardware organizations and companies
Open hardware electronic devices
Open-source hardware
Cryptographic hardware | Nitrokey | [
"Engineering"
] | 968 | [
"Cybersecurity engineering",
"Computer access control"
] |
49,031,352 | https://en.wikipedia.org/wiki/Single-parameter%20utility | In mechanism design, an agent is said to have single-parameter utility if his valuation of the possible outcomes can be represented by a single number. For example, in an auction for a single item, the utilities of all agents are single-parametric, since they can be represented by their monetary evaluation of the item. In contrast, in a combinatorial auction for two or more related items, the utilities are usually not single-parametric, since they are usually represented by their evaluations to all possible bundles of items.
Notation
There is a set of possible outcomes.
There are agents which have different valuations for each outcome.
In general, each agent can assign a different and unrelated value to every outcome in .
In the special case of single-parameter utility, each agent has a publicly known outcome proper subset which are the "winning outcomes" for agent (e.g., in a single-item auction, contains the outcome in which agent wins the item).
For every agent, there is a number which represents the "winning-value" of . The agent's valuation of the outcomes in can take one of two values:
for each outcome in ;
0 for each outcome in .
The vector of the winning-values of all agents is denoted by .
For every agent , the vector of all winning-values of the other agents is denoted by . So .
A social choice function is a function that takes as input the value-vector and returns an outcome . It is denoted by or .
Monotonicity
The weak monotonicity property has a special form in single-parameter domains. A social choice function is weakly-monotonic if for every agent and every , if:
and
then:
I.e, if agent wins by declaring a certain value, then he can also win by declaring a higher value (when the declarations of the other agents are the same).
The monotonicity property can be generalized to randomized mechanisms, which return a probability-distribution over the space . The WMON property implies that for every agent and every , the function:
is a weakly-increasing function of .
Critical value
For every weakly-monotone social-choice function, for every agent and for every vector , there is a critical value , such that agent wins if-and-only-if his bid is at least .
For example, in a second-price auction, the critical value for agent is the highest bid among the other agents.
In single-parameter environments, deterministic truthful mechanisms have a very specific format. Any deterministic truthful mechanism is fully specified by the set of functions c. Agent wins if and only if his bid is at least , and in that case, he pays exactly .
Deterministic implementation
It is known that, in any domain, weak monotonicity is a necessary condition for implementability. I.e, a social-choice function can be implemented by a truthful mechanism, only if it is weakly-monotone.
In a single-parameter domain, weak monotonicity is also a sufficient condition for implementability. I.e, for every weakly-monotonic social-choice function, there is a deterministic truthful mechanism that implements it. This means that it is possible to implement various non-linear social-choice functions, e.g. maximizing the sum-of-squares of values or the min-max value.
The mechanism should work in the following way:
Ask the agents to reveal their valuations, .
Select the outcome based on the social-choice function: .
Every winning agent (every agent such that ) pays a price equal to the critical value: .
Every losing agent (every agent such that ) pays nothing: .
This mechanism is truthful, because the net utility of each agent is:
if he wins;
0 if he loses.
Hence, the agent prefers to win if and to lose if , which is exactly what happens when he tells the truth.
Randomized implementation
A randomized mechanism is a probability-distribution on deterministic mechanisms. A randomized mechanism is called truthful-in-expectation if truth-telling gives the agent a largest expected value.
In a randomized mechanism, every agent has a probability of winning, defined as:
and an expected payment, defined as:
In a single-parameter domain, a randomized mechanism is truthful-in-expectation if-and-only if:
The probability of winning, , is a weakly-increasing function of ;
The expected payment of an agent is:
Note that in a deterministic mechanism, is either 0 or 1, the first condition reduces to weak-monotonicity of the Outcome function and the second condition reduces to charging each agent his critical value.
Single-parameter vs. multi-parameter domains
When the utilities are not single-parametric (e.g. in combinatorial auctions), the mechanism design problem is much more complicated. The VCG mechanism is one of the only mechanisms that works for such general valuations.
See also
Single peaked preferences
References
Mechanism design | Single-parameter utility | [
"Mathematics"
] | 1,022 | [
"Game theory",
"Mechanism design"
] |
49,031,464 | https://en.wikipedia.org/wiki/Edwina%20Cornish | Edwina Cecily Cornish is an Australian biologist and academic, specialising in biotechnology. Between 2012 and 2016 she was Provost and Senior Vice-president of Monash University. She was previously Deputy Vice-Chancellor (Research) at the University of Adelaide and then at Monash University.
Early life and education
Cornish studied at the University of Melbourne, and graduated with a Bachelor of Science with Honours (BSc (Hons)) degree in biochemistry and a Doctor of Philosophy (PhD) degree in microbiology.
Career
From 2000 to 2004, Cornish was Professor of Biotechnology and Deputy Vice-Chancellor (Research) at the University of Adelaide.
Cornish joined Monash University as Deputy Vice-Chancellor (Research) in 2004, and was promoted to Senior Deputy Vice-Chancellor in 2009. Between 2012 and 2016 she was Provost (Chief Academic Officer) and Senior Vice-president of Monash University.
In November 2015, Cornish was appointed a board member of the Commonwealth Scientific and Industrial Research Organisation for a five-year term.
Honours
In 2001, Cornish was awarded the Centenary Medal "for service to Australian society in biotechnology and university administration". In the 2014 Queen's Birthday Honours, she was appointed an Officer of the Order of Australia (AO) "for distinguished service to higher education, to advances in biotechnology and horticultural genetic modification, and through fostering of partnerships with government, industry and the community".
On 13 March 2013, Cornish was inducted into the Victorian Honour Roll of Women "for providing inspirational leadership as a pioneer in the biotechnology industry and as a transformational leader at Monash University". She is an elected Fellow of the Australian Academy of Technological Sciences and Engineering (FTSE).
References
Living people
Year of birth missing (living people)
Place of birth missing (living people)
Australian biologists
Biotechnologists
Women biotechnologists
Academic staff of the University of Adelaide
Academic staff of Monash University
Women academic administrators
Officers of the Order of Australia
Fellows of the Australian Academy of Technological Sciences and Engineering
University of Melbourne alumni
Australian academic administrators | Edwina Cornish | [
"Biology"
] | 406 | [
"Biotechnologists",
"Women biotechnologists"
] |
49,031,794 | https://en.wikipedia.org/wiki/Asynchrony%20%28computer%20programming%29 | Asynchrony, in computer programming, refers to the occurrence of events independent of the main program flow and ways to deal with such events. These may be "outside" events such as the arrival of signals, or actions instigated by a program that take place concurrently with program execution, without the program hanging to wait for results. Asynchronous input/output is an example of the latter case of asynchrony, and lets programs issue commands to storage or network devices that service these requests while the processor continues executing the program. Doing so provides a degree of concurrency.
A common way for dealing with asynchrony in a programming interface is to provide subroutines that return a future or promise that represents the ongoing operation, and a synchronizing operation that blocks until the future or promise is completed. Some programming languages, such as Cilk, have special syntax for expressing an asynchronous procedure call.
Examples of asynchrony include the following:
Asynchronous procedure call, a method to run a procedure concurrently, a lightweight alternative to threads.
Ajax is a set of client-side web technologies used by the client to create asynchronous I/O web applications.
Asynchronous method dispatch (AMD), a data communication method used when there is a need for the server side to handle a large number of long lasting client requests. Using synchronous method dispatch (SMD), this scenario may turn the server into an unavailable busy state resulting in a connection failure response caused by a network connection request timeout. The servicing of a client request is immediately dispatched to an available thread from a pool of threads and the client is put in a blocking state. Upon the completion of the task, the server is notified by a callback. The server unblocks the client and transmits the response back to the client. In case of thread starvation, clients are blocked waiting for threads to become available.
See also
Asynchronous system
Asynchronous circuit
References
Computer programming
Inter-process communication
Middleware | Asynchrony (computer programming) | [
"Technology",
"Engineering"
] | 432 | [
"IT infrastructure",
"Computer programming",
"Computer science stubs",
"Software engineering",
"Computer science",
"Middleware",
"Computing stubs",
"Computers"
] |
49,032,691 | https://en.wikipedia.org/wiki/OST%20Family | Members of the organic solute transporter (OST) family (TC# 2.A.82) (Slc51 genes) have been characterized from a small bottom feeding species of fish called the little skate, Raja erinacea. Members have also been characterized from humans and mice. The OST family is a member of the larger group of secondary carriers, the APC superfamily.
Substrates
Substrates for OST transporters include a variety of organic compounds, most being anionic. Transport of estrone sulfate by the two subunit Ost transporter of Raja erinacea (TC# 2.A.82.1.1) is Na+-independent, ATP-independent, saturable and inhibited by other steroids and anionic drugs. Bile acids such as taurocholate as well as digoxin and prostaglandin E2 are substrates of this system, while estradiol 17β-D-glucuronide and p-aminohippurate are apparently not. Mammalian homologues (e.g., 2.A.82.1.2) similarly exhibit broad substrate specificity, transporting the same compounds, possibly by an anion:anion exchange mechanism.
Transport reaction
The generalized transport reaction catalyzed by OSTα/OSTβ is:
organic anion (out) ⇌ organic anion (in)
Structure
Each transport system consists of two polypeptide chains, designated α and β. For the human protein (TC# 2.A.82.1.2), the α-subunit is of 340 amino acyl residues (aas) with 7 putative transmembrane segments (TMSs) while the β-subunit is of 128 aas with 1 putative TMS near the N-terminus (residues 40-56). Neither OSTα nor OSTβ alone has activity, both serving not only for heterodimerization and trafficking but also for function. The two proteins are highly expressed in many human tissues. The β-subunit is not required to target the α-subunit to the plasma membrane, but coexpression of both genes is required to convert OSTα to the mature glycosylated protein in enterocyte basolateral membranes and possibly for trafficking through the golgi apparatus. OSTαβ proteins are made in a variety of tissues including the small intestine, colon, liver, biliary tract, kidney, and adrenal gland. In polarized epithelial cells, they are localized to the basolateral membrane and function in the export or uptake of bile acids and steroids. Homologues of OSTα are found in many eukaryotes including animals (both vertebrates and invertebrates), plants, fungi and slime molds. Homologues of OSTβ are found only in vertebrate animals.
Crystal structures
As of early 2016, no crystal structures had been determined. However, bioinformatics utilizing combinations of homology modelling and mutation experiments have been used to explore the heterdimer nature of the system as well as the mechanisms of substrate recognition and transport.
See also
Organic cation transport proteins
Organic anion-transporting polypeptide
Solute carrier family
Osmoregulation
Organic anion transporter 1
Transporter Classification Database
References
Further reading
Membrane proteins
Enzymes of known structure
Solute carrier family
Transmembrane proteins
Transmembrane transporters
Transport proteins
Integral membrane proteins | OST Family | [
"Biology"
] | 715 | [
"Protein classification",
"Membrane proteins"
] |
49,032,906 | https://en.wikipedia.org/wiki/David%20Benney | David John Benney (8 April 1930 – 9 October 2015) was a New Zealand applied mathematician, known for work on the nonlinear partial differential equations of fluid dynamics.
Education and early life
Born in Wellington, New Zealand, on 8 April 1930 to Cecil Henry (Matt) Benney and Phyllis Marjorie Jenkins, Benney was educated at Wellington College. He graduated BSc from Victoria University College in 1950, and MSc from the same institution in 1951. He then went to Emmanuel College, Cambridge, from where he graduated BA in the Mathematical Tripos in 1954. He was at Canterbury University College for two years as a lecturer, before taking leave of absence in August 1957 to undertake doctoral studies at Massachusetts Institute of Technology (MIT), graduating PhD in 1959.
Career and research
Benney joined the mathematics faculty at MIT in 1960. He spent the rest of his career there, as a prolific researcher in fluid dynamics and supervisor of students, becoming emeritus professor. He received a Guggenheim Fellowship in 1964.
Notes
References
1930 births
2015 deaths
New Zealand mathematicians
Fluid dynamicists
Victoria University of Wellington alumni
Academic staff of the University of Canterbury
Alumni of Emmanuel College, Cambridge
Massachusetts Institute of Technology School of Science faculty
People educated at Wellington College, Wellington
Massachusetts Institute of Technology School of Science alumni | David Benney | [
"Chemistry"
] | 251 | [
"Fluid dynamicists",
"Fluid dynamics"
] |
49,032,980 | https://en.wikipedia.org/wiki/%C3%8Ele%20Raphael | Île Raphael is an island in the Saint Brandon archipelago, a group of 30 outer islands of Mauritius. The island is named after Veuve Raphaël.
Veuve Raphaël's husband was a sea captain and had installations on the corner of rue (route) des Pamplemousses and rue Fanfaron in Port Louis. Captain Raphaël travelled regularly to Île Raphael, St Brandon from Port Louis and, on 17 May 1816 and November 1817, is on record as bringing back salted fish (Poisson Salé) on a Lugger called 'Le Cheriby' ('angel' in old French). Île Raphaël is today the headquarters and principal fishing base of the Raphael Fishing Company which is the second oldest commercial company in Mauritius.
Population
Today, Île Raphael's population amounts to around 40 people and constitutes the majority of Saint Brandon's entire resident population. Some employees of Raphael Fishing Company stay and work on the island for periods of up to seven months, depending on the season.
Key Biodiversity Area
In 1968, the island was visited by the Mauritian scientist France Staub and his seminal work called Birds of the Mascarenes and Saint Brandon was partially based on his experiences here. In the Chapter (7) called Seabirds of Saint Brandon, Staub lists breeding seabirds and determines that Saint Brandon then had amongst 'the largest colonies in the world of Sooty Tern'.
This island is located on the Cargados Carajos coral reef atoll system, part of a CEPF designated Key Biodiversity Area (KBA) in the Southwest Indian Ocean. The Cargados Carajos are closely skirted by busy Southeast Asian shipping lanes (North and South of the Archipelago) making its unique ecosystem vulnerable to a variety of risks which pose threats to its long-term existence as a Key Biodiversity Area.
Ongoing and future threats include: -
(i) Rust & heavy metal seepage from existing shipwrecks into coral reefs.
(ii) Seepage of rust and heavy metals from future shipwrecks
(iii) Spillage of petroleum/ heavy oil as a direct consequence of new shipwrecks
(iv) Cyclones and high winds up to with associated flooding.
(v) Tsunami, potentially from any future earthquake in southern Sumatra to the East and, speculatively, from the Reunion Hotspot inter alia
(vi) Outbreaks of disease and importation of Invasive Alien Species (IAS) into its globally unique flora and fauna.
Image gallery
See also
Mascarene Islands
St Brandon
France Staub
Avocaré Island
L'île du Sud
L'île du Gouvernement
Permanent grant
L'Île Coco
Raphael Fishing Company
Mauritian Wildlife Foundation
References
Islands of St. Brandon
Outer Islands of Mauritius
Reefs of the Indian Ocean
Fishing areas of the Indian Ocean
Insular ecology
Important Bird Areas of Mauritius
Atolls of the Indian Ocean
Biodiversity
Quarantine facilities
Fly fishing
Fishing tournaments
Environment of Mauritius
Natural history of Mauritius | Île Raphael | [
"Biology"
] | 594 | [
"Biodiversity"
] |
49,033,936 | https://en.wikipedia.org/wiki/TSUP%20family | The 4-Toluene Sulfonate Uptake Permease (TSUP) family (TC# 2.A.102) is also referred to as the TauE/SafE/YfcA/DUF81 Family.
Although its members have not been rigorously characterized, evidence is available that at least some members function in the transport of Sulfur containing Organic compounds. These include 4-toluene sulfonate which may be transported by the TsaS of Cupriavidus necator (TC# 2.A.102.1.1), sulfolactate which may be exported by the TauE protein of Cupriavidus necator (TC# 2.A.102.2.1) and sulfoacetate which may be exported by the SafE1 protein of Neptuniibacter caesariensis (TC# 2.A.102.2.2). Another member of the TSUP family, TsaS of Comamonas testosteroni, has been reported to function in the uptake of 4-toluene sulfonate. None of these functional assignments can be considered to be certain.
References
Further reading
Protein families
Membrane proteins
Transmembrane proteins
Transmembrane transporters
Transport proteins
Integral membrane proteins | TSUP family | [
"Biology"
] | 261 | [
"Protein families",
"Protein classification",
"Membrane proteins"
] |
49,035,916 | https://en.wikipedia.org/wiki/Monument%20to%20the%20Sun | Monument to the Sun or The Greeting to the Sun () is a monument in Zadar, Croatia dedicated to the Sun. It consists of a 22-meter diameter circle representing the Sun, with three hundred, multi-layered glass plates placed on the same level as the stone-paved waterfront, with photovoltaic solar modules underneath. Lighting elements installed in the circle turn on at night and produce a light show. Smaller circles represent the planets. The monument symbolizes communication with nature, communicates with light, while the nearby Sea organ communicates with sound. The monument to the Sun and the Sea organ were both designed by Croatian architect Nikola Bašić.
Location
The monument is located at the entrance to the port of the Croatian town of Zadar on the western point of the Zadar Peninsula.
Design
The monument consists of 300 multi-layered glass plates, placed level with the stone paving of the waterfront, arranged in the shape of a 22-meter diameter circle. Beside the main “Sun” installation, looking from the west are similar, smaller installations representing the planets of the Solar System. The size of the Sun and planets are proportional, as well as the distance from the center of each plate, but the size and distance proportions differ as the planets are so far away. Beneath the glass panels are photovoltaic solar modules with lighting elements, which turn on at night to produce a light show.
A chrome ring on the perimeter of the Sun installation is inscribed the names of all titular saints of churches on the Zadar Peninsula. The monument is also a calendar as beside the saints’ names are their feast days, along with the following information for each date: solar declination and solar altitude north or south of the equator (DEC minimum of -23° to a maximum of 23°); the length of sunlight in the meridian on that date and at the waterfront. This was prepared in cooperation with marine scientist Professor Maksim Klarin from Zadar Maritime School, who also programmed the light show's start and end times for 50 years starting in 2008.
The planetary installations meanwhile have similar rings, inscribed with their name in Croatian as well as their astronomical symbol.
Solar modules
The photovoltaic solar modules absorb light energy, transform it into electricity, and release it into the power network. The entire system annually produces about 46,500 kWh, producing half the energy needed by the Zadar waterfront.
Cost
The construction cost was 8 million kunas (excluding VAT) (c. 1,3 million euros), while the overall cost (including landscaping) totaled 50 million kunas (c. 7 million euros). Maintenance due to its exposure to sunlight, moisture and salt from 2008-2013 totaled around 700 thousand kunas. An extensive renovation and upgrade project worth 4 million kunas was completed in March 2019.
Vandalism
Damage, such as cracks on solar modules, have been seen on several occasions, mostly on the Sun installation, where 12 solar modules have been damaged, as well as on the Jupiter and Saturn installations. The cracks were caused by a 3500 kg pickup truck that drove over the modules. The City added a 24-hour supervisor and surveillance cameras. In June 2009, an unidentified object smashed four modules, and on the night of August 8, two more. On May 5, 2019, a young man smashed modules with a hammer, causing €90,000 worth of damage.
Gallery
See also
Zadar
Architecture of Croatia
Nine Views, a Solar System model in Zagreb, Croatia
References
Buildings and structures completed in 2008
Zadar
Buildings and structures in Zadar
Tourist attractions in Zadar
Buildings and structures in Zadar County
Monuments and memorials in Croatia
Vandalized works of art
Solar System models | Monument to the Sun | [
"Astronomy"
] | 750 | [
"Space art",
"Solar System models",
"Solar System"
] |
49,037,112 | https://en.wikipedia.org/wiki/Q-plate | A q-plate is an optical device that can form a light beam with orbital angular momentum (OAM) from a beam with well-defined spin angular momentum (SAM). Q-plates are based on the SAM-OAM coupling that may occur in media that are both anisotropic and inhomogeneous, such as an inhomogeneous anisotropic birefringent waveplate. Q-plates are also currently realized using total internal reflection devices, liquid crystals, metasurfaces based on polymers, and sub-wavelength gratings.
The sign of the OAM is controlled by the input beam's polarization.
References
Optical components
Nonlinear optics | Q-plate | [
"Materials_science",
"Technology",
"Engineering"
] | 141 | [
"Glass engineering and science",
"Optical components",
"Components"
] |
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