id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
63,937,042 | https://en.wikipedia.org/wiki/TRiC%20%28complex%29 | T-complex protein Ring Complex (TRiC), otherwise known as Chaperonin Containing TCP-1 (CCT), is a multiprotein complex and the chaperonin of eukaryotic cells. Like the bacterial GroEL, the TRiC complex aids in the folding of ~10% of the proteome, and actin and tubulin are some of its best known substrates. TRiC is an example of a biological machine that folds substrates within the central cavity of its barrel-like assembly using the energy from ATP hydrolysis.
Subunits
The human TRiC complex is formed by two rings containing 8 similar but non-identical subunits, each with molecular weights of ~60 kDa. The two rings are stacked in an asymmetrical fashion, forming a barrel-like structure with a molecular weight of ~1 MDa.
Molecular weight of human subunits.
Counterclockwise from the exterior, each ring is made of the subunits in the following order: 6-8-7-5-2-4-1-3.
Evolution
The CCT evolved from the archaeal thermosome ~2Gya, with the two subunits diversifying into multiple units. The CCT changed from having one type of subunit, to having two, three, five, and finally eight types.
See also
Chaperone
Chaperonin
Heat shock protein
Notes
References
Gene expression
Protein complexes | TRiC (complex) | [
"Chemistry",
"Biology"
] | 295 | [
"Gene expression",
"Molecular genetics",
"Cellular processes",
"Molecular biology",
"Biochemistry"
] |
63,938,049 | https://en.wikipedia.org/wiki/Sophie%20LaRochelle | Sophie LaRochelle is a Canada Research Chair and professor of engineering at Université Laval. She specializes in developing fiber optic components for signal-processing and data transmission in telecommunication networks.
Education
LaRochelle earned a Ph.D. in Optics from the University of Arizona College of Optical Sciences in 1992. Her thesis, "Origin and applications of photosensitivity in germanium‐doped silica optical fibers", was supervised by George I. Stegeman. She obtained her M.Sc. in Physics and B.Sc. in Engineering Physics from Université Laval.
Research and career
LaRochelle was appointed to the faculty of the Department of Electrical and Computer Engineering at Université Laval in 1996. Prior to her appointment at Université Laval, she was a Defense Scientist at DRDC Valcartier. She was appointed by Canada's Minister of Science to the Governing Council for the Natural Sciences and Engineering Research Council of Canada in 2015. Currently, LaRochelle is the Director of the Center for Optics, Photonics and Lasers (COPL), a multi-institutional research network in the Province of Quebec.
LaRochelle's research activities focus on optical fiber components, fiber laser systems, integrated photonics, and optical networking. She has made significant contributions to the development of passive and active fiber devices and their application to optical signal processing. She is known for inventing fiber optic components including super-structured fiber Bragg gratings for chromatic dispersion equalizers, multi-wavelength fiber lasers and optical code division multiplexing. Her work has been published in more than 150 scientific articles and she has directed the research work of over 70 graduate students and post-doctoral fellows.
Awards and honors
LaRochelle was Holder of the Canada Research Chair (Tier 2) in Optical Fiber Communications and Components from 2000–2010. Since 2012, she has been Holder of the Canada Research Chair (Tier 1) in Advanced Photonics Technologies for Communications. She was inducted as a Fellow of the Optical Society in 2015, and as an IEEE Fellow in 2021, "for contributions to fiber devices and data transmission technologies". LaRochelle was elected to the Board of Directors of The Optical Society in 2019 and will serve through 2021.
References
Canada Research Chairs
Fellows of Optica (society)
University of Arizona alumni
Women in optics
Université Laval alumni
Academic staff of Université Laval
Fiber optics
Year of birth missing (living people)
Living people
Optical engineers
Telecommunications engineers
Fellows of the IEEE | Sophie LaRochelle | [
"Engineering"
] | 499 | [
"Telecommunications engineering",
"Telecommunications engineers"
] |
63,938,121 | https://en.wikipedia.org/wiki/The%20Gramercy | The Gramercy is a mixed-use development project in Spring Valley, Nevada, west of the Las Vegas Strip. It includes two office buildings and 160 apartment units. Gemstone Development began construction of the project, originally known as ManhattanWest, in 2007. The project initially was to include condominiums, retail, and office space. Construction was suspended in December 2008, because of financial problems. ManhattanWest was sold in 2013, and construction resumed, with the project now known as The Gramercy. It opened in November 2014. An unfinished nine-story condominium tower was imploded in February 2015, as completing it would have been too costly.
History
ManhattanWest
In 2006, Gemstone Development completed a 700-unit condominium property called Manhattan, located south of the Las Vegas Strip. That year, the company purchased a 20-acre property in Spring Valley, Nevada (southwest Las Vegas), near the Las Vegas Beltway. The purchase cost $30 million, and was financed by Theraldson Financial Group. As of July 2006, Gemstone was planning to build a condominium project on the newly acquired land, under the name ManhattanWest. Like the earlier project, ManhattanWest would also contain 700 units. They would be housed in a nine-story tower and a series of four-story buildings. The mixed-use development project would also include office and retail space.
ManhattanWest was designed by Denver-based Oz Architecture, while Apco Construction was the general contractor. Developer Alex Edelstein, the chief executive officer of Gemstone, was confident that the project would succeed despite a poor housing market in Las Vegas. Excavation work began on the site in April 2007. Vertical construction of the first phase – three residential buildings and two commercial buildings – was expected to begin in the third quarter of 2007. ManhattanWest was expected to begin opening during the third quarter of 2008, with full completion by mid-2009.
Buildings in the project had Manhattan-inspired names, including Tribeca House and Gramercy House. The flagship nine-story building, known as Element House, would include 73 units, a fitness center, and a rooftop deck and lounge with views of the Las Vegas Strip and Red Rock Canyon. The two other residential buildings, as well as the two office buildings, were four stories high. The complex would ultimately consist of 12 buildings, and would include of Class A office space, as well as of ground-floor retail space. The project would feature approximately 30 retailers and four restaurants.
By November 2007, the project had experienced strong pre-sales, despite the poor market. More than 50 percent of the first phase had sold out within the first six months, making it one of the best-selling condominium projects in the United States. Unit prices on the project had been raised five times up to that point, and construction was proceeding on a continuous schedule to get the first five buildings finished. One aspect of the project that garnered attention from prospective buyers was ManhattanMD, an on-site medical facility for residents. The project was expected to cost $330 million. Construction costs were low at the time because of decreased demand in the housing market. Edelstein remained confident in the project and had invested more than half of his net worth into it.
Element House was topped off in August 2008. At the time, Edelstein had made a preliminary agreement with InterContinental Hotels to open a 120-room Staybridge Suites hotel at ManhattanWest, catering to business travelers. Camco Pacific Construction became the new general contractor in September 2008. Edelstein cited poor construction work by Apco as the reason for the change, and additional money had to be spent on reworking and rebuilding parts of the project that were deemed inadequate. The project had 58 building code violations, including faulty structural concrete and an inadequate fire safety system. At the time of the contractor change, Element House was 80 percent complete, while the Union Square commercial plaza was scheduled for completion later in the year. The first phase was scheduled for full completion around March 2009.
Edelstein announced the suspension of construction on December 16, 2008, as financing was no longer available. The announcement was made during the Great Recession, and Edelstein said a primary reason for the suspension was "a mismatch of what it costs to build one of these things and what people are willing to pay for condos and office space." He also blamed significant cost increases that were necessary to fix the earlier work done by Apco. Edelstein said these increased costs were what led to the lenders terminating the project's financing. He hoped to eventually acquire new financing to finish ManhattanWest.
Edelstein had spent $170 million on the project, which was considered an eyesore in the years after work was suspended. The nine-story tower was vandalized, with glass paneling being smashed, while copper wiring was stolen from the building. More than $30 million in liens were filed against ManhattanWest following the suspension. A legal battle developed, involving the banks that financed the project and construction companies that were owed money for their work. By March 2009, Edelstein had talked with several groups that were interested in purchasing the project, but he said that none of them had any serious offers.
Gemstone filed for bankruptcy in 2011. The H5 Group, founded by Ofir Hagay, was in the process of purchasing the project out of bankruptcy during 2012. Before the purchase could be approved by a bankruptcy judge, a creditor stated that the sale price was too low, prompting an auction in an effort to bring in a higher price. The Calida Group, a Nevada housing developer, was in the process of purchasing the project at the end of 2012.
The Gramercy
Krausz Companies, based in California, ultimately purchased ManhattanWest in June 2013, for $20 million. Krausz teamed up with WGH Partners, based in Las Vegas, to develop the unfinished project. Hagay was among the partners at WGH, which was also a co-owner of the project. The companies planned to spend an additional $30 million to finish the project, which would be renamed The Gramercy and would retain its New York theme. The companies planned to finish the residential units as apartment rentals rather than condominiums. Because of the legal problems associated with the project, it took more than a year to work out the issues and finalize the purchase. Some issues involving lienholders and lenders still remained after the sale, although these were not expected to have an effect on the project. WGH was interested in the project because of its size and design, and its location near the Las Vegas Beltway.
Construction was underway again in March 2014, with Martin-Harris Construction as the general contractor. The first office and residential tenants were expected to begin moving in later that year. HMS Holdings signed a deal to become the first major office tenant, leasing in The Gramercy. Regus also signed on as an office tenant. Other tenants have included Bank of Internet USA, CalAtlantic Homes, and Liberty Mutual. WGH believed that there was strong demand in the area for restaurants, prompting the decision to include several eateries at The Gramercy. Retail was no longer planned for the project, and options were being considered for the decrepit nine-story tower. The Gramercy's opening was marked on November 6, 2014, with the installation of a 10,000-pound letter "G" sculpture.
A decision was ultimately made to demolish the tower, as finishing it would be too costly because of the building code violations that would need to be addressed. Company executives also felt that the tower's blue glass exterior did not match with the rest of the project. The owners opted to have the tower demolished piece-by-piece, a process that would take months. Demolition began in mid-January 2015, with jackhammering on the top floor. However, the noise could be heard for several blocks away, and there were concerns that it would lead to complaints from office tenants and that it would cause disinterest in prospective apartment renters. A week after demolition began, the owners decided to have the tower demolished through implosion instead.
In preparation for the implosion, the tower was stripped down to a bare frame of steel and concrete. The tower was imploded on the morning of February 15, 2015. The tower had an underground parking garage that extended east of the building by 60 feet. The garage's ceiling was demolished, and the implosion was planned so that the tower would collapse into the garage. It was expected to take four to six weeks to clear the debris and demolish the garage. Potential plans for the now-vacant property included building another tower, possibly with office space. A 90-foot-tall sign was installed at The Gramercy in March 2015.
The Gramercy has 160 apartment units. A courtyard surrounds the various businesses located on the ground-floor, which includes restaurants and a fitness center. At the end of 2016, the last of the remaining office space was being prepared for incoming tenants. In April 2017, the two commercial buildings were sold for $61.75 million to two real estate firms, Koll Company and Estein USA, based respectively in California and Florida. The remainder of The Gramercy – including the apartment buildings and 12.6 acres of vacant property and parking lots – was sold to California-based developer Lyon Living in May 2018, for $45.75 million. The apartment units accounted for $37 million of the sale price. In September 2020, Lyon Living announced plans for a six-story apartment building with 294 units, to be built on the former land of the imploded tower as well as adjacent property. Construction on the apartment building, known as The Highline, began in November 2021 and is expected to conclude two years later.
References
External links
Official website
Residential buildings in the Las Vegas Valley
Buildings and structures in Spring Valley, Nevada
2014 establishments in Nevada
Residential buildings completed in 2014
Office buildings in Nevada
Office buildings completed in 2014
Mixed-use developments in the United States
Buildings and structures demolished by controlled implosion
Buildings and structures demolished in 2015
Unfinished buildings demolished | The Gramercy | [
"Engineering"
] | 2,078 | [
"Buildings and structures demolished by controlled implosion",
"Architecture"
] |
63,939,133 | https://en.wikipedia.org/wiki/Jos%C3%A9%20Arechabala%20S.A. | José Arechabala S.A. (founded as La Vizcaya in 1878) was one of the Cuban conglomerates within the sugar and alcoholic beverages industries. Headquartered in Cárdenas, Matanzas, it is known for Havana Club rum from 1934 until 1960.
History
José Arechabala Aldama, a Spanish industrialist, established a distillery named La Vizcaya in 1878 in Cárdenas, Matanzas, Cuba. The distillery used the molasses residue from sugar refining to produce rum and other liquors. It also provided logistic services in the port of Cárdenas including warehouses and sea transport. This development allowed it to cope with losses due to Hurricane Faquineto, which amounted to 50,000 pesos in 1888 (around 2 million USD today). Its expansion continued despite the Cuban War of Independence (where Cárdenas was the first location bombed by the US Navy), Cuban independence from Spain, and subsequent associated crises.
By 1919, the group included a power plant, sugar refineries, and a barrel production facility; the distillery was producing 23,600 liters of rum and 80,000 liters of other spirits daily and managed schooners and warehouses.
These businesses were incorporated under the José Arechabala S.A. name on January 18, 1921. The founder became its first chairman, while his son-in-law (and nephew), José Arechabala Sainz, became managing director. The Arechabala facilities in the Cárdenas shore extended over 150 acres.
José Arechabala died on March 15, 1923, and his successor as chairman, José Arechabala Sainz, was assassinated only a few months later, in September 1924. The subsequent successor, Gabriel Malet, died in 1926. It was then that Tomás Pita y Álvarez took over as the chairman and José Fermín Iturrioz was appointed managing director. At that time, the Prohibition in the United States was still in force, preventing any alcohol exports to the largest market. However, several negotiations with American authorities secured a 22% quota on sugar imports into the United States, to be split proportionally among the Cuban producers. In 1932, Cuba exported 435,000 tons of sugar to the United States, 30% of which was refined by José Arechabala S.A.
When Prohibition was about to be repealed, another Category 5 hurricane hit Cárdenas. On 1 September 1933, the 1933 Cuba–Brownsville hurricane reached the Matanzas shore, causing extensive damage and hundreds of deaths.
After the hurricane, the company began construction on a new rum production plant, which was inaugurated on March 19, 1934 (festivity of St. Joseph, the founder's patron). This plant had the purpose of launching the Havana Club and Doubloon Rum brands, which were targeted for the U.S. market. The popularity of Arechabala Havana Club's rum increased soon afterwards. On May 29, José Arechabala S.A. opened a new office building and its "Bar Privado’’ (the “Havana Club’’) across the Havana Cathedral. It soon became one of the hotspots for locals and tourists in Havana, as protagonist James Wormold mentioned in the novel Our Man in Havana: “at the Havana Club he Felt a Citizen of Havana." Additionally, the Havana Club held receptions for the Athletic Bilbao team that had won the Spanish League in July 1935 and for the Juan Sebastián Elcano officers when they stopped over in Havana in April 1936.
During the 1940s and the 1950s, the corporation continued its expansion into fuel production, a shipyard, a jam factory, a yeast plant, and a bagasse paper mill. During this time, the leadership was in the hands of Carmela Arechabala, the eldest daughter of José Arechabala, who assumed chairmanship in 1946. By then, the corporation refined 1,000,000 pounds of sugar, purified 200,000 liters of water, and distilled 125,000 liters of alcohol daily, while the fermentation section was able to handle up to 4,000,000 liters and the solera aged 2,000,000 liters of rum on an ongoing basis. In 1953, to celebrate the corporation's 75th anniversary, the Arechabala 75 rum was released.
Reorganization
In 2004, one of the managers of the distillery later claimed to the US Senate that he fled the Cuban Revolution with nothing but the knowledge of the secret formula for making Havana Club rum.
From that date on, a period of disregard and differences in management began. The Cuban Revolution abandoned the production assets, giving away the aging barrels, which in turn ruined the business. The Bar Privado was abandoned, and the production plants were unoccupied.
Benefactora eminente
When José Arechabala S.A. unveiled the Arechabala Theater on April 20, 1919, the city of Cárdenas was prompt in naming the founder Hijo Adoptivo, but the social works fostered by the firm did not stop there. On May 19 May 1945, on the occasion of the inauguration of the Monumento a la Bandera that culminated the works on the Cárdenas coastline that had been borne by José Arechabala S.A., the then President of the Republic, Ramón Grau San Martín, unveiled a plaque that declared José Arechabala S.A. as Benefactora eminente (eminent benefactor) of the city. These works had allowed the port of Cárdenas to be dredged, making it a development pole for the region, enhancing its position as the closest port to the United States. That same day, José Arechabala S.A. was appointed Gran Oficial del Mérito Comercial by the Cuban government.
Fringe benefits for workers
The Arechabala employees enjoyed services provided by their company. The plant in Cárdenas had a swimming pool, social club, children's playground, Balneario (seaside resort) or sport fields (including tennis, golf or bowling, among others). In January 1945, another social club was opened in Varadero for the workers of Arechabala. Additionally, services for employees provided by José Arechabala S.A. included:
Professional Dental Service
Canteen for workers
Emergency Aid Savings Bank
Sewing Academy for the families of the employees
Scholarships for children of employees
Pension Fund and retirements for employees
Draw of 2 houses every year among Arechabala employees
Symbols
José Arechabala S.A. used an emblem with the Biscay coat of arms, which depicted the oak tree of Guernica (Arechabala is a Basque word that means "large oak tree") and the wolves representing the López de Haro (founders of Bilbao), "ravissant’’ (i.e. carrying a lamb in their mouth) for their participation in the Battle of Las Navas de Tolosa in 1212. This symbol appeared on the labels of all Arechabala products (including the original Havana Club bottles) from the foundation of the distillery and adorned the barrels on the solera.
From 1943, there was a change in the Havana Club image, as the label became blue and the emblem a combination in two panels of the Biscay coat of arms and the Bilbao coats of arms with the San Antón Bridge. By the end of 1954, another image change was produced and the label returned to a similar version of the original one, with the oak tree of Guernica and the wolves.
See also
List of companies of Cuba
References
Food and drink companies of Cuba
Drink companies of Cuba
Distilleries
Rums
Sugar companies
Sugar industry of Cuba
Companies established in 1878
1878 establishments in Cuba
Cárdenas, Cuba
Companies disestablished in 1960
1960 disestablishments in Cuba | José Arechabala S.A. | [
"Chemistry"
] | 1,578 | [
"Distilleries",
"Distillation"
] |
66,749,514 | https://en.wikipedia.org/wiki/Maritime%20sociology | Maritime sociology is a sub-discipline of sociology studying the relationship of human societies and cultures to the oceans and the marine environment as well as related social processes. Subjects studied by maritime sociology are human activities at and with the sea such as seafaring, fisheries, maritime and coastal tourism, off-shore extraction, deep-sea mining, or marine environmental conservation. Institutions and discourses related to those activities are also studied by the sub-discipline. Another area of study is the societal-natural relations in the marine realm such as, for instance, the problem of over-fishing or the social consequences of climate change. In sum, maritime sociology conceptualizes the oceans as a social rather than a merely natural space.
Relation to other sociological disciplines
Maritime sociological research is often closely related, uses theories and methods of and collaborates with other sub-disciplines such as the sociology of work or environmental sociology.
Schools and institutions
Although it is almost as old as the sociological discipline itself, maritime sociology has not been institutionalized to any great extent to date and is practiced by various more or less independent schools around the world. Currently, there are efforts within the research community to establish maritime sociology as an independent sub-discipline.
The Polish universities of Szczecin, Gdansk, and Poznan are national centers of research mainly in the sociology of maritime professions. After the second world war, when the Polish coastline had increased significantly due to the outcome of the war, maritime matters became important subject of political and scientific discourse in Poland leading to the establishment of maritime sociology.
From 1985 to 1992, there was a working group at the Institute of Sociology at Christian-Albrechts-University in Kiel, Germany that aimed to establish maritime sociology in Germany.
Several Chinese universities (Ocean University, Shanghai Ocean University) conduct research in and operate institutes of maritime sociology. The discipline was also institutionalized in the Chinese academic landscape by founding a professional committee in the Chinese Sociological Association in 2010.
Since 2009, research streams on maritime sociology take place regularly at the biannual conference of the European Sociological Association
Centers in Canada are the Memorial University in Newfoundland, Dalhousie University, St. Francis Xavier University, University of British Columbia and the University of Toronto. These Canadian research efforts mainly focus on environmental aspects of the human-ocean relation and fisheries research.
Theoretical positions
Until now, there is no established theoretical framework or overarching paradigm of maritime sociology. Sociological studies in maritime subjects share the identity of dealing with subjects related to the sea rather than a common theoretical ground. With the exception of Janiszewski's concept of marinization, maritime sociologists borrow theoretical approaches from other sociologies to apply them to their field.
Marinization
Since the 1970s, the Polish sociologist Ludwik Janiszewski's developed the theory of "marinization" (Polish: "Marynizacja"). Analogous to ideas like industrialization, urbanization, or digitalization, the notion describes a historical process or tendency of increasing entanglement of terrestrial societies with the maritime realm, or a tendency of growing importance of relations with and the use of the sea for human societies.
Critical political economy of oceans
Scholars using the critical political economy approach draw on theories about the interaction of the capitalist mode of production with the ocean in the Marxist tradition. One strand of this approach is concerned with environmental and sustainability issues, using social-ecological theories such as social metabolic analysis. John Hannigan criticizes that its proponents fail to conceptualize the ocean as a distinct social space but, instead, remain in a terrestrial bias applying the categories of land-based society to the maritime realm.
Another strand under the umbrella of critical political economy focuses on the role of the sea with regard to international trade, migratory movements of people, and relations of maritime labor, and piracy. An early publication of this research direction was Steinberg's book "The Social Construction of the Ocean". A recent publication exploring the sociology of the oceans from a critical political economy perspective is presented by Liam Campling and Alejandro Colás: "[...] we aim to demonstrate how capitalism has transformed the spatial relationship between land and sea in ways that has made them both increasingly interdependent and resolutely differentiated."
Posthumanist and postmodern theories
Recently, a number of maritime sociology researchers draw on theories of posthumanism and postmodernism to conceptualize human-ocean relations. In the sense of Actor-Network-Theory and the works of feminist scholar Donna Haraway, they argue for transcending the separation of nature and society, conceptualizing the oceans as a "hybrid" instead of viewing it separately as a social and natural space.
Fields of research
Examples of maritime-sociological research and theory building include:
Ferdinand Tönnies' empirical study of the social situation of dockworkers and seafarers in Northern-German seaports.
Norbert Elias' work on the origins of the naval profession in England
The academic controversy weather the ship is a total institution. While most maritime scholars studying seafaring subscribe to the notion, there is also critique on the application of the concept arguing that a merchant ship is not a disciplinary institution and can therefore not be adequately be described in these terms.
The works of the Seafarers International Research Centre (SIRC) at Cardiff University. The members of the research center conduct research in the social situation of global seafarers in the world's merchant fleets.
Related Journals
Currently, there are no scientific journals exclusively dedicated to the subject of maritime sociology. Below is a list of interdisciplinary journals covering the subject:
Asia-Pacific Journal of Marine Science & Education
Constanta Maritime University Annals
Marine Policy
Maritime Policy & Management
Maritime Studies
Pomorstvo. Scientific Journal of Maritime Research
Roczniki Socjologii Morskiej. Annals of Maritime Sociology (1986-2016)
WMU Journal of Maritime Affairs
References
Oceanography
Environmental sociology | Maritime sociology | [
"Physics",
"Environmental_science"
] | 1,189 | [
"Hydrology",
"Applied and interdisciplinary physics",
"Oceanography",
"Environmental sociology",
"Environmental social science"
] |
66,749,629 | https://en.wikipedia.org/wiki/AMG-333 | AMG-333 is a drug which acts as a potent and selective blocker of the TRPM8 ion channel, which is the main receptor responsible for the sensation of cold. It was developed as a potential treatment for migraine.
See also
PF-05105679
RQ-00203078
References
Pyridines
Trifluoromethyl ethers
Amides
Fluoroarenes
Carboxylic acids | AMG-333 | [
"Chemistry"
] | 90 | [
"Pharmacology",
"Carboxylic acids",
"Functional groups",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Amides"
] |
66,749,916 | https://en.wikipedia.org/wiki/Gregory%20Anthony%20Perdicaris | Gregory Anthony Perdicaris (originally Gregores Antones Perdicaris, ; 1810 – April 18, 1883) was a Greek American statesman, lawyer, professor, author, and entrepreneur. Perdicaris raised awareness about Greece in the United States during the Greek War of Independence and was in Greece during the critical early years. He was the first Consul of the United States for Greece. He is known for incorporating dozens of companies in the United States. Perdicaris and partners built the municipal framework for gas and electric companies. He was associated with Dewing v. Perdicaries, 96 U.S. 193 (1877), the Supreme Court case dealing with Confederate Sequestration. He was a prominent resident of Trenton, New Jersey.
Early life
Gregores Antones Perdicaris was born in Naousa, a city in the present Imathia regional unit of Macedonia, Greece. He was son of Antones Perdicaris a doctor and politician. The Perdicaris family is an aristocratic Greek family with centuries-old origins in Crete, Corfu and Monemvasia. The Patriarch Licinius, the personal doctor to the Ottoman Sultan, was named a Count by the Republic of Venice for his services, and was beheaded by the Ottomans for the same reason in 1715. Gregory Perdicaris was about 12 years old when he fled the Massacre of Naousa in 1822. Perdicaris and his father fled into the mountains. His two brothers-in-law were killed. His mother, two brothers, and four sisters were taken by the Ottomans and sold into slavery. He eventually fled to Izmir without his father. Afterward, he made his way to Jerusalem where he met Pliny Fisk. Fisk helped secure his passage to the United States. He was brought to America on the ship Romulus on July 7, 1826. On his way to the United States, he was told his family's freedom was purchased. He was sixteen and traveled with Nicolus Prassas and Nicolus Vlassopoulo, none of whom spoke English.
In the later part of the 1820s he learned English and taught at Mount Pleasant Classical Institute. While he was at Mount Pleasant he wrote Suffering Greece; the essay was published in local newspapers. It was an outcry to the people of the United States about war-torn Greece. While Perdicaris was at Mount Pleasant he taught with Petros Mengous author of the book Narrative of a Greek Soldier in 1830. Their students included John C. Zachos, Christophoros Plato Castanes, Alexandros Georgios Paspates, Constantine Fundulakes, and Christopher Evangeles.
By 1830, he was a professor at Washington College, now Trinity College in Hartford Connecticut. He was a Greek teacher from 1830 to 1832 and librarian at the institution from 1832 to 1833. He also obtained a master's degree at the college. Prominent future Harvard Professor Evangelinos Apostolides Sophocles lived in Hartford Connecticut during this period. Around 1834, Perdicaris wrote Dr. Coray and the Greek Church. The essay discussed the future of the Greek government and the Greek Church. Perdicaris traveled to many American cities lecturing about Greece from 1834-1837.
His lectures created awareness about the war-torn country and its current state. The themes varied from the: Moral and Intellectual Condition on Modern Greece, History and Topography of Macedonia, and the modern Greek language vs Ancient Greek. He also discussed education in the country prior to the war. He briefly lectured at Yale and Harvard University. Gregory was made an Honorary member of Yale's Phi Beta Kappa in 1834. Phi Beta Kappa eventually made him a life member. Some of the prominent locations he lectured included: the Franklin Institute, New York Mercantile Library, Washington D.C., and the Brooklyn Lyceum.
His lectures usually cost 50 cents per person, per lecture, and 2 dollars per person, for the entire series. American Poet Edgar Allan Poe enjoyed his lectures and featured two articles about them in the Southern Literary Messenger between 1836 and 1837.
His lectures were so popular local newspapers gave Perdicaris rave reviews.
Around the fall of 1837, Perdicaris was in North Carolina lecturing. He suddenly stopped his lecture tour around May 1837. He married Margret Hanford on May 25, 1837, in Society Hill, South Carolina. Margret was the granddaughter of American Revolutionary War hero Captain William Dewitt. They were a politically elite Southern family of planters. Margret was an orphan but her sister Mary married into the family of Governor David Rogerson Williams. Mary's husband was State Congressman Alexander Markland McIver. Their son was Chief Justice of the South Carolina Supreme Court Henry McIver. Margret's uncle was Senator Josiah J. Evans.
Greek consul
Greece was officially recognized by the United States in 1837. Gregory became the first American Consul to Athens, Greece in October 1837, under the appointment of President Martin Van Buren. It took Perdicaris and his wife sixty days to travel to Greece. He officially assumed his post in Athens, Greece on January 7, 1838. Perdicaris attended the Royal Court of King Otto and Queen Amalia. Perdicaris interacted with the heroes that helped Greece gain its independence. The diplomatic community consisted of dignitaries from 18 different countries. Some of the countries included: Austria, Bavaria, Belgium, Denmark, Great Britain, Hanover, Netherlands, Papal Dominions, Portugal, Russia, Prussia, Saxony, Sardinia, Tuscany, Two Sicily’s, Sweden, and the United States. Two notable members of the community were David Pacifico and Jonas King.
Gregory served both the United States and Greece during his time as Consul. He evaluated legal matters regarding the American missionaries that were living in Greece at the time. Gregory also helped gather American funding for different Greek projects. The National and Kapodistrian University of Athens was established. Perdicaris was a member of two American societies: the Natural History Society and the Archaeological Society. Perdicaris also joined the Educational Society (Φιλεκπαιδευτική Εταιρεία). This Greek organization helped establish schools in the country. Godey's Magazine published an article by Gregory Anthony Perdicaris in July 1841, entitled The Court of King Otho. Perdicaris discussed the Court of the King and how the Greek revolutionaries interacted with the foreign dignitaries.
Prominent Greek revolutionary Petrobey Mavromichalis was introduced to Unitarian Minister Charles Lowell of Massachusetts by his friend Perdicaris. Lowell was so taken by Mavromichalis that he published his plea for funds in American newspapers. Charles Lowell wrote the kindest words about the Spartan Greek war hero. In 1840, Perdicaris son Ion Hanford Perdicaris was born in Athens, Greece. Margret wrote letters about her experiences in Greece to Anna McIver, Henry McIver's sister. Anna archived the communications, they can be found in the Anna R. McIver Papers. Greece experienced a revolution around the time the King's Royal Palace was completed in Athens. The coup was called the 3 September 1843 Revolution. The King immediately agreed to the demands for a constitutional monarchy. Perdicaris was back in the United States in the latter part of 1843. The consul took a leave of absence.
Gregory wrote the Greece of Greeks. The book was published in the later part of 1845 in two volumes. The book outlines the time he spent in Greece. He describes the different cities he visited. He relayed what he observed, and the interactions he had with the local inhabitants. A notable part of the book describes a nun who had visions of an icon from the island of Dino just before Perdicaris arrived in Greece. He describes how the nun was instructed to find the icon of the Virgin. A church was built Our Lady of Tinos to house the holy relic. Perdicaris said that many pilgrims traveled to the holy church. Outside of the church, there was a festival to raise money. The money was used to build roads and help the newly formed democracy.
Return to the United States
Gregory and his family settled in Trenton, New Jersey. They moved into the Perdicaris Ashley Cottage, a notable estate in Trenton. He resigned his position as consul on February 2, 1845. Records indicate he was considering a professorship in South Carolina. He finished his two-volume book while in the United States. In early 1846, he lectured about his book in Trenton at the Irving Institute. In May of the same year, he was the vice president of the Mexican–American War Committee. Other members of the committee included Mayor of Trenton Charles Burroughs and Governor Peter D Vroom. Perdicaris became a trustee at the Trenton Academy in 1847 he held this position until 1880. Other notable trustees included: William Lewis Dayton, Edward W. Scudder, Mayor Charles Burroughs, Samuel R. Gummeré’s father Barker Gummere. Perdicaris was a manager at the Trenton Saving Fund Society from 1847-1878. Notable managers of the society included: Samuel D. Ingham, Edward W. Scudder, Governor Peter D Vroom.
Perdicaris was active in the Democratic Party. He attended a meeting on March 5, 1847. In the summer, he attended the Committee for the Mexican-American War for a second year. The newspapers reported in November 1847, he lost the political race for New Jersey Assembly representing Mercer County. Xenophon J. Maynard, Joseph C. Potts, Perdicaris, and several others participated in the incorporation of the Trenton Gas Light Company on February 19, 1847. One year later Perdicaris was one of the directors. Perdicaris was now involved in the coal gas business. Joseph C. Potts, James Hoy Jr., and Perdicaris built the coal gas plant and infrastructure of Princeton Gas Light Company in 1849. That same year notable members of the Trenton community Peter Cooper, Abram Hewitt, and Perdicaris attended the New Jersey State Tariff Convention. Perdicaris participated in discussions regarding trade, they were adopted by the convention.
Perdicaris was the president of the Trenton Mutual Life and Fire Insurance Company in 1852. Perdicaris, Joseph C Potts, and Xenophon J. Maynard were on the Board of Directors of the Pacific Mutual Insurance Company. The secretary was James Hoy Jr. In 1852, Perdicaris presided as director of the Trenton Library with Charles Hewitt, Barker Gummere, and several others. Former Treasury Secretary Ingham was president. Perdicaris contributed to A Pronouncing Gazetteer with the pronunciation of the Greek language. Thomas A. Baldwin published the book in 1851.
On January 9, 1854, Perdicaris was involved with the Committee on the Inauguration of Governor-Elect Rodman McCamley Price. Perdicaris ran a campaign for School Trustee that same year with Democratic Mayor William Napton. He lost the election. He was secretary of the Camden & Amboy Rail Road and Transportation Company in 1856 and manager of the Trenton Water Works in 1858. During the year 1859, Perdicaris incorporated the Trenton City Bridge Company with Thomas J Stryker, Barker Gummere, and several others.
Coal gas
The coal gas plants were a form of municipal infrastructure. The coal gas was supplied to street lamps throughout the cities. The town gas was also sent to people's homes. It was used to cook, illuminate and warm houses. The coal gas plants were eventually converted to gas and electric companies. Perdicaris played a major part in organizing the early framework. Perdicaris and Hoy were paid with stock certificates which they eventually sold into the open market. In some instances they were part of incorporating the coal gas company, then they hired Perdicaris and Hoy to build the plants and infrastructure.
Perdicaris and James Hoy Jr. started to build coal gas plants all over the country. Aaron Vancleve was the engineer. He owned an iron foundry in Trenton and was their business partner. Vancleve built plants in Virginia traveling from city to city. The cities included: Richmond, Wheeling, Alexandria and Petersburgh. Perdicaris and Hoy was the name brand of the company building the plants. Portsmouth Gas Company, Saint Paul Gas Light Company, Hudson and Bergen Gas Light Company, Natchez Gas Light Company, Macon Gas Light Company, Columbus Gas Light Company, Charleston Gas Light Company, and Charlottesville and University Gas Light are some of the companies involved with Perdicaris and Hoy. Eventually James Hoy's cousin John Patterson Kennedy became the coal gas plant engineer. Perdicaris and Hoy were in business from 1849 to 1860.
James Hoy retired leaving Perdicaris and Hoy. Kennedy Partnered with his sons James Hoy Jr and William Hoy. The new company was called Kennedy & Hoy. Kennedy & Hoy partnered with Cornelius Vanderbilt and his son to build the largest coal gas infrastructure in this countries history. The company was called the New York Mutual Gas Light Company and it was built in New York City. It was later absorbed by Con-Edison.
American Civil War
Ion Hanford Perdicaris graduated from Trenton Academy with William Lewis Dayton Jr. and William Hoy in 1855. The next year he enrolled at Harvard as a freshman, he also displayed his painting Cattle at the Thirty-Third Annual Exhibition of the Pennsylvania Academy of the Fine Arts. Evangelinos Apostolides Sophocles was a professor at Harvard around this time. By the spring of 1858, Ion was no longer a student at Harvard. He traveled to England that summer to study painting.
Gregory was an active member of Trinity Church, which was formed in 1858. The church was built in Trenton on Academy St. around 1860. Perdicaris was elected vestryman on April 27, 1859. He was also a delegate to the diocesan convention that same year. He repeated this role the following year and was an active member of the church. The country was on the verge of war. Perdicaris was with the North and his wife was with her family in the South. A similar scenario to Theodore Roosevelt Sr. and his wife's family.
Margret's nephew Henry McIver was instrumental in removing South Carolina from the United States. He signed the Ordinance of Secession in December 1860. He demanded his first cousin Ion Hanford Perdicaris assist in the war efforts. Gregory was crucial because he was a former diplomat and had ties to many different countries in Europe namely the King and Queen of Greece. They were related to other royals throughout the European continent. Recall there were over 18 different countries represented with over 50 different consuls in the diplomatic community when they were in Greece. The information was relayed to the McIver's and can be found in the McIver papers.
The McIvers confiscated the family's assets one month after the onset of the civil war and three months before the official Confederate Sequestration Act. The McIver's did not hire a substitute for their cousin who was studying in Europe. They choose confiscation. One year later, the confederacy confiscated 1351 shares of the Charleston Gas Light Company, worth close to one million dollars, adjusted for 2019 inflation. The shares belonged to Gregory.
This resulted in the Supreme Court case Dewing v. Perdicaris, 96 U.S. 193 (1877). Ion Hanford Perdicaris according to his letter to Samuel R. Gummeré was instructed by his parents to obtain Greek citizenship to stop the sequestration. They found expatriation a legal solution. Expatriation was not legally allowable until the Expatriation Act of 1868.
Records indicate Ion submitted his paperwork twenty-three days before the South sequestered close to one million dollars worth of stocks. By law, he was still an American citizen.
Later life
In the 1860s, Gregory was manager at the Trenton Saving Fund Society and the Trenton Bridge Company. He was very active in Trenton his duties included working at the waterworks and he was involved with the Delaware and Raritan Canal Company. He was heavily involved with municipal infrastructure. Perdicaris and his wife dedicated the continuation of State Street through their twelve-acre property. Their house the Perdicaris Ashley Cottage was torn down and rebuilt between Clinton and Chestnut. The 1870 map of Trenton reveals Perdicaris owned countless land parcels. He sold and rented houses.
By the year 1867, Perdicaris, Peter Cooper, Theodore Roosevelt Sr., and John C. Zachos all donated money for the Greek refugees of Crete to Samuel Gridley Howe. Perdicaris became very active in incorporating new companies in the late 1860s, early 1870s. Some of the companies included: Holmes Gold Company of Montana, Ransome Patent Stone Company, Hamilton Horse Car Railroad, Jersey Silver Mining Company, Rosario Silver Mining Company, Star Rubber Company, and The Poplar Creek Railroad, Coal, and Iron Company. Some of his business partners included Barker Gummeré, John A Roebling, Abram Hewitt's younger brother Charles Hewitt. Peter Cooper became really close friends with John C. Zachos. Zachos wrote his biography and was the curator of the library at Cooper Union. In 1877, Gregory's son Ion freed a slave in Morocco with the help of the United States government. It was widely publicized in Trenton newspapers.
In 1878, Perdicaris left his position at the bank after 31 years. He became president of the Princeton Gas Light Company. Two years later he retired from Trenton. Gregory and his wife moved to Tangier Morocco. He died three years later in 1883, his wife passed two years after his death. The city of Trenton honored Perdicaris by naming a street and neighborhood after him. In the early 20th century the Perdicaris Ave. Bridge in Trenton shared his name. His home town Naousa, also has 2 streets named after later members of the Perdicari family; the first is named after Christodoulos Perdicaris, a doctor and a leading figure in the independence struggle of Northern Greece/ Makedonia and the second after Georgios Perdicaris, a two-times town mayor. Gregory's son Ion inherited a massive fortune and was involved in the Perdicaris affair.
Legacy
Perdicaris Place in Trenton, New Jersey, is named in his honor.
Literary works
Essays
Suffering Greece (Phenix Gazette, 1827)
Dr. Coray and the Greek Church (The American Quarterly Observer Volume 2, 1834)
The Court of King Otho (Godey's Lady's Book, Vol. 23, 1841)
Books
The Greece of the Greeks Vol 1 1846
The Greece of the Greeks Vol 2 1846
See also
Gas lighting
References
Bibliography
1810 births
1883 deaths
Trinity College (Connecticut) faculty
Trinity College (Connecticut) alumni
Greek emigrants to the United States
19th-century Greek Americans
American Civil War industrialists
Coal gas-fired power stations
Coal gasification technologies
19th-century American politicians
People from Trenton, New Jersey
People from Naousa, Imathia
19th-century Greek educators
19th-century Greek businesspeople
19th-century Greek writers
19th-century Greek historians
American writers of Greek descent
Greece–United States relations
19th-century American diplomats
19th-century American writers | Gregory Anthony Perdicaris | [
"Chemistry"
] | 3,922 | [
"Coal gasification technologies",
"Synthetic fuel technologies"
] |
66,750,346 | https://en.wikipedia.org/wiki/LUMI | LUMI (Large Unified Modern Infrastructure) is a petascale supercomputer located at the CSC data center in Kajaani, Finland. In January 2023, the computer became the fastest supercomputer in Europe.
The completed system consists of 362,496 cores, capable of executing more than 375 petaflops, with a theoretical peak performance of more than 550 petaflops, which places it among the most powerful computers in the world. The November 2022 TOP500 ranks LUMI at number five, with a measured performance of 309.1 PFLOPS.
Architecture
The system is being supplied by Hewlett Packard Enterprise (HPE), providing an HPE Cray EX supercomputer with next generation 64-core AMD EPYC CPUs and AMD Radeon Instinct GPUs. LUMI is a GPU based system, and the majority of its computing power comes from its GPU cores, an architecture which was chosen primarily for its cost/performance advantage. The system is equipped with 1.75 petabytes of RAM, and storage includes a 7-petabyte partition of flash storage, combined with 80-petabytes of traditional storage, both based on the Lustre parallel file system, as well as a 30-petabyte data management service based on Ceph. This gives the system a total of 117 petabytes of storage with an aggregated I/O bandwidth of 2 terabytes per second.
Funding
LUMI is co-funded by the EuroHPC Joint Undertaking and the LUMI Consortium, which is composed of the following countries: Finland, Belgium, Czech Republic, Denmark, Estonia, Iceland, Norway, the Netherlands, Poland, Sweden, and Switzerland. The total budget is €144.5 million.
Energy
The computer uses 100% hydroelectric energy, and the heat it generates will be captured and used to heat buildings in the area, making LUMI one of the most environmentally efficient supercomputers in the world. The former UPM paper mill where LUMI is located had only a single 2 minute power outage during its 38 years of operations thanks to the site's reliable connection to the national grid.
Operation
Half of LUMI's capacity belongs to the EuroHPC Joint Undertaking, 20% of which is reserved for industry and SME use. The other half is shared among the LUMI Consortium countries, according to each country’s financial contribution.
By June 2021 pilot projects had been selected for the first run of the CPU partition, scheduled for September 2021, with full operations including the GPU partition planned for 2022.
Naming
The word "lumi" means "snow" in Finnish.
See also
Leonardo, another EuroHPC supercomputer under construction in Bologna, Italy
EuroHPC (European High-Performance Computing Joint Undertaking).
References
Cray products
Petascale computers
Supercomputing in Europe
Kajaani
Information technology in Finland | LUMI | [
"Technology"
] | 606 | [
"Supercomputing in Europe",
"Supercomputing"
] |
66,753,141 | https://en.wikipedia.org/wiki/TRPM4-IN-5 | TRPM4-IN-5 is a drug which acts as a moderately potent but highly selective blocker of the TRPM4 ion channel, with an IC50 of 1.5 μM. It is protective against glutamate mediated neuronal excitotoxicity.
References
Carboxylic acids
Amides
2-Chlorophenyl compounds
Chloroarenes | TRPM4-IN-5 | [
"Chemistry"
] | 81 | [
"Pharmacology",
"Carboxylic acids",
"Functional groups",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Amides"
] |
66,753,770 | https://en.wikipedia.org/wiki/List%20of%20Zink%20cameras%2C%20printers%20and%20paper | This is a list of cameras, printers and paper for use with the Zink full-color printing technology.
Zink Paper printers
Zink Paper printers print photographs onto mostly 2×3" (about 5×8 cm) sheets of Zink Paper, though some print onto 3×4" (about 8×10 cm) paper, and some print onto 2.3×3.4" (5.8×8.6 cm) paper.
Dell Wasabi (PZ310)
Canon IVY (U.S.A.) or Zoemini (Europe) – produces 2×3" prints
HP Sprocket
HP Sprocket Plus - produces 2.3×3.4" (5.8×8.6 cm) prints
HP Sprocket 200
LG Pocket Photo (PD233)
LG Pocket Photo 2 (PD239)
LG Pocket Photo 3 (PD251)
Lifeprint
Polaroid Grey Label GL10 (PLDGL10PRINTR) – produces 3×4" prints. Discontinued.
Polaroid PoGo
CZA-10011B
CZU-10011B
CZA-20011B
Polaroid Zip Instant Photoprinter (POLMP01)
Prynt Case (later called Prynt Classic)
Prynt Pocket
Brother VC-500W
Huawei Pocket Photo Printer
Mi Portable Photo Printer
Combined digital cameras and Zink printers
HP Sprocket Two-in-one / 2-in-1 – The combined camera-printer version of the Sprocket.
Kodak Printomatic – Instant Print 10 MP Digital Camera that produces 2×3" sticky-backed prints
Kodak Smile – Instant Print 10 MP Digital Camera with LCD viewfinder that produces 2×3" sticky-backed prints
Kodak Smile Classic – Instant Print Digital Camera that produces 3.25×4.5" sticky-backed prints
Polaroid PoGo (CZA-05300) – a 5 MP digital camera that produces 2×3" prints
Polaroid PIC-1000 – a 12 MP digital camera that produces 3×4" prints
Polaroid Z340 – a 14 MP digital camera that produces 3×4" prints
Polaroid Z2300 Digital Instant Print Camera (POLZ2300) – a 10 MP digital camera that produces 2×3" prints
Tomy Xiao (TIP-521) – a 5 MP digital camera that produces 2×3" prints
Polaroid Socialmatic – a 14 MP digital camera with 4.5" LCD screen, produces 2×3" prints
Polaroid Snap Instant Digital Camera (POLSP01) – a 10 MP digital camera that produces 2×3" prints
Polaroid Snap Plus – a 13 MP digital camera with 3.5" LCD screen, produces 2×3" prints.
Polaroid Pop (announced at CES 2017) – 3.5×4.25" format
Zink zRoll printers
Stylised as ZINK hAppy. Marketed as a "smart app printer". Launched in 2013.
Zink Happy from Zink Imaging
Zink Happy+ from Zink Imaging
Paper formats
Zink Paper
Zink Photo Paper (POLZPPxxx)† – 2×3" (about 5×7.6 cm) sheets
Zink Photo Paper (POLZ3X4xx) – 3×4" (about 8×10 cm) sheets
Premium Zink Photo Paper (POLZ2X3xx) – 2×3" sheets
Premium Zink Rainbow Photo Paper (POLZ2X3xxRB) – 2×3" sheets
HP Sprocket Photo Paper – 2×3" (5×7.6 cm) sheets
HP Sprocket Plus Photo Paper – 2.3×3.4" (5.8×8.7 cm) sheets
Zink zRoll - available in a variety of widths
† The 'x' in the model represents the number of sheets of paper in the pack.
Notes
References
External links
Zink Holdings LLC
Computer printers
Instant photography
Polaroid cameras
Printing materials
Coated paper
Photography equipment
Zink cameras, printers and paper
Lists of cameras | List of Zink cameras, printers and paper | [
"Physics"
] | 832 | [
"Printing materials",
"Materials",
"Matter"
] |
66,754,473 | https://en.wikipedia.org/wiki/Sandes%20%28software%29 | Sandes is an Indian state-owned freeware instant messaging platform developed by the Government of India. It runs on Android, iOS and in web browsers. The platform is hosted exclusively at Government infrastructure and both are governed by the rules and regulations of Government of India.
Sandes offers instant messaging, VoIP, File sharing and integration within various Indian Government digital services. In initial releases it was only accessible by government officials but now it is available for the public. At present, full features of the platform are only available to verified users.
History
In 2019, the Government of India started a project to build an instant messaging platform named Government Instant Messaging System (GIMS) as part of its Make in India initiative. The main goal of the project was to provide a secure messaging platform to government employees for internal communication which doesn't arouse the security concerns attached with the communication platforms hosted abroad or those owned by foreign entities. The initial software testing started in mid-September 2019 and ran for an extensive period of time. Around 6,600 government officials from various departments participated in this pilot program which reported to have exchanged about 20 lakh messages. Later in February 2021 the client application was rebranded as Sandes and published in the official website. This time the program was made available to the public in limited number.
The Delhi police used the Sandes app to discuss sensitive information about dignitaries during the G20 summit. India's paramilitary forces transitioned to the 'Sandes App' for official communication and document sharing in January 2024, replacing WhatsApp.
In July 2024, the Maharashtra government mandated the use of the Sandes app for all official communications to enhance operational security and detect potential misuse.
Features
Sandes allows users to make end-to-end encrypted one-to-one and group messages. Also allows users to make end-to-end encrypted one-to-one voice and video calls. Messaging features include forward, forward to mail, broadcast, backup, text customization and tag. Tag is a functionality to mark a message as Confidential, on Priority or as Auto Delete. If a message is marked Auto Delete, then it will be automatically deleted once the recipient reads it. Currently Sandes is integrated with NIC email, DigiLocker and eOffice. So users can access these services without leaving the platform.
Limitations
A valid mobile number is required to sign up. Public users are limited to one-to-one chat. An official group is limited to 200 members. A casual group is limited to 50 members. Broadcast list is limited to ten contacts at a time. Users are only allowed to send the following file types: documents (doc, docx, xls, xlsx, ppt, pptx, pdf), images (jpeg, jpg, png), audio (mp3, m4a), video (mp4). File size is limited to 15mb per file.
See also
WhatsApp
Signal (software)
Telegram (software)
Session (software)
References
External links
Digital India initiatives
National Informatics Centre
Modi administration initiatives
Instant messaging
Freeware | Sandes (software) | [
"Technology"
] | 638 | [
"Instant messaging"
] |
66,755,060 | https://en.wikipedia.org/wiki/Azure%20Linux | Azure Linux, previously known as CBL-Mariner (in which CBL stands for Common Base Linux), is a free and open-source Linux distribution that Microsoft has developed. It is the base container OS for Microsoft Azure services and the graphical component of WSL 2.
Overview
Azure Linux is being developed by the Linux Systems Group at Microsoft for its edge network services and as part of its cloud infrastructure. The company uses it as the base Linux for containers in the Azure Stack HCI implementation of Azure Kubernetes Service. Microsoft also uses Azure Linux in Azure IoT Edge to run Linux workloads on Windows IoT, and as a backend distro to host the Weston compositor for WSLg.
In a similar approach to Fedora CoreOS, Azure Linux only has the basic packages needed to support and run containers. Common Linux tools are used to add packages and manage security updates. Updates are offered either as RPM packages or as complete disk images that can be deployed as needed. Using RPM allows adding custom packages to a base Azure Linux image to support additional features and services as needed. Notable features include an iptables-based firewall, support for signed updates, and a hardened kernel.
Microsoft released the operating system in 2020. Its source code is available on GitHub, mainly under the MIT License, with some components under , Apache License v2, GPLv2, and LGPLv2.1. Building Azure Linux requires the Go programming language, QEMU utilities, and RPM.
Starting from the release 2.0.20240301, Azure Linux was renamed from CBL-Mariner.
See also
SONiC (operating system)
Windows Subsystem for Linux
Azure Sphere
References
Further reading
Azure Kubernetes Service on Azure Stack HCI: deliver Storage Spaces Direct to containers
Enabling Linux based Azure IoT Edge Modules on Windows IoT
2020 software
Computing platforms
Enterprise Linux distributions
Free and open-source software
Linux containerization
Linux distributions
Microsoft free software
Microsoft operating systems
Software using the GNU General Public License
Software using the MIT license | Azure Linux | [
"Technology"
] | 423 | [
"Operating system stubs",
"Computing stubs",
"Computing platforms"
] |
66,755,839 | https://en.wikipedia.org/wiki/Abiological%20nitrogen%20fixation%20using%20homogeneous%20catalysts | Abiological nitrogen fixation describes chemical processes that fix (react with) N2, usually with the goal of generating ammonia. The dominant technology for abiological nitrogen fixation is the Haber process, which uses iron-based heterogeneous catalysts and H2 to convert N2 to NH3. This article focuses on homogeneous (soluble) catalysts for the same or similar conversions.
Transition metals
Vol'pin and Shur
An early influential discovery of abiological nitrogen fixation was made by Vol'pin and co-workers in Russia in 1970. Aspects are described in an early review:
"using a non-protic Lewis acid, aluminium tribromide, were able to demonstrate the truly catalytic effect of titanium by treating dinitrogen with a mixture of titanium tetrachloride, metallic aluminium, and aluminium tribromide at 50 °C, either in the absence or in the presence of a solvent, e.g. benzene. As much as 200 mol of ammonia per mol of was obtained after hydrolysis.…" These results led to many studies on dinitrogen complexes of titanium and zirconium.
Mo- and Fe-based systems
Because Mo and Fe are found at the active site of the most common and most active form of nitrogenase, these metals have been the focus of particular attention for homogeneous catalysis. Most catalytic systems operate according to the following stoichiometry:
N2 + 6H+ + 6e− → 2NH3
The reductive protonation of metal dinitrogen complexes was popularized by Chatt and coworkers, using Mo(N2)2(dppe)2 as substrate. Treatment of this complex with acid gave substantial amounts of ammonium. This work revealed the existence of several intermediates, including hydrazido complexes (Mo=N-NH2). Catalysis was not demonstrated. Schrock developed a related system based on the amido Mo(III) ocomplex Mo[(HIPTN)3N]. With this complex, catalytic nitrogen fixation occurred, albeit with only a few turnovers.
Intense effort has focussed on family of pincer ligand-supported Mo(0)-N2 complexes. In terms of it donor set, and oxidation state, these pincer complexes are similar to Chatt's complexes. Their advantage is that they catalyze the hydrogenation of dinitrogen. A Mo-PCP (PCP = phosphine-NHC-phosphine) complex exhibits >1000 turnovers when the reducing agent is samarium(II) iodide and the proton source is methanol.
Iron complexes of N2 are numerous. Derivatives of Fe(0) with C3-symmetric ligands catalyze nitrogen fixation.
Photolytic routes
Photolytic nitrogen splitting is also considered.
p-Block systems
Although nitrogen fixation is usually associated with transition metal complexes, a boron-based system has been described. One molecule of dinitrogen is bound by two transient Lewis-base-stabilized borylene species. The resulting dianion was subsequently oxidized to a neutral compound, and reduced using water.
Nitriding
Particular metals can react with nitrogen gas to give nitrides, a process called nitriding. For example, metallic lithium burns in an atmosphere of nitrogen, giving lithium nitride. Hydrolysis of the resulting nitride gives ammonia. In a related process, trimethylsilyl chloride, lithium and nitrogen react in the presence of a catalyst to give tris(trimethylsilyl)amine, which can be further elaborated. Processes that involve oxidising the lithium metal are however of little practical interest, since they are non-catalytic and re-reducing the ion residue is difficult. The hydrogenation of Li3N to produce ammonia has seen some exploration since the resulting lithium hydride can be thermally decomposed back to lithium metal.
Some Mo(III) complexes also cleave N2:
2Mo(NR2)3 + N2 → 2N≡Mo(NR2)3
This and related terminal nitrido complexes have been used to make nitriles.
See also
Nitrogenase: enzymes used by organisms to fix nitrogen
Transition metal dinitrogen complex
Metal nitrido complex
References
Homogeneous catalysis | Abiological nitrogen fixation using homogeneous catalysts | [
"Chemistry"
] | 892 | [
"Catalysis",
"Homogeneous catalysis"
] |
66,760,902 | https://en.wikipedia.org/wiki/Psychoinformatics | Psychoinformatics is an emerging interdisciplinary field that uses principles from computer science for the acquisition, organization, and synthesis of data collected from psychology to reveal information about psychological traits such as personality and mood. The term may also be used in context of affective computing or character computing.
Psychology has historically relied on experiments and questionnaires in order to collect data. These methods face several disadvantages, namely that experiments often consist of a small quantity of users (who must be incentivized to participate) and self-reported questionnaires and interviews are subject to bias and unreliable memory. Psychoinformatics solves these problems by storing Big Data related to psychology (such as communications on smartphones or social media websites) and then data mining for relevant psychological information.
See also
affective computing
Bioinformatics
Neuroinformatics
Psychometrics
Quantitative psychology
References
Subfields of computer science
Interdisciplinary branches of psychology | Psychoinformatics | [
"Technology"
] | 185 | [
"Computer science",
"Subfields of computer science"
] |
66,760,969 | https://en.wikipedia.org/wiki/Iron%28II%29%20nitrate | Iron(II) nitrate is the nitrate salt of iron(II). It is commonly encountered as the green hexahydrate, Fe(NO3)2·6H2O, which is a metal aquo complex, however it is not commercially available unlike iron(III) nitrate due to its instability to air. The salt is soluble in water and serves as a ready source of ferrous ions.
Structure
No structure of any salt Fe(NO3)2·xH2O has been determined by X-ray crystallography. Nonetheless, the nature of the aquo complex [Fe(H2O)6]2+ is well known and relatively insensitive to the anion. The Fe-O distances are longer for [Fe(H2O)6]2+ (2.13 Å) than for the ferric analogue [Fe(H2O)6]3+ (1.99 Å). Both [Fe(H2O)6]n+ complexes are high spin, which results in pale colors, paramagnetism, and weak Fe-O bonds.
Production
Iron(II) nitrate can be produced in multiple ways, such as the reaction of iron metal with cold dilute nitric acid:
If this reaction is conducted below -10 °C, nonahydrate is produced. It readily releases water to give the hexahydrate.
The above reaction can also co-produce ferric nitrate. Reacting iron(II) sulfate and lead nitrate under dilute ethanol and then evaporating the solution leads to the formation of the green crystals of the hexahydrate. A solution of iron(II) nitrate is produced by the ion-exchange reaction of iron(II) sulfate and barium nitrate, producing a concentration of up to 1.5 M due to the limited solubility of barium nitrate.
The solution of the iron(II) nitrate-hydrazine complex is produced by the reaction of hydrazine nitrate and ferric nitrate at 40 °C with copper(II) nitrate as a catalyst:
If the compound is used in situ, the compound is produced by the reaction of iron(II) chloride and calcium nitrate:
Reactions
The hexahydrate melts at 60 °C and then decomposes at 61 °C into iron(III) oxide rather than iron(II) oxide. A solution of iron(II) nitrate is much more stable, decomposing at 107 °C to iron(III), with the presence of nitric acid lowering the decomposition temperature. Concentrated nitric acid oxidizes iron(II) nitrate into iron(III) nitrate:
Uses
Iron(II) nitrate has no uses, however, there is a potential use for dye removal.
References
Iron(II) compounds
Nitrates
Orthorhombic crystals | Iron(II) nitrate | [
"Chemistry"
] | 580 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
66,761,886 | https://en.wikipedia.org/wiki/HD%2095086 | HD 95086, formally named Aiolos, is a pre-main-sequence star about away. Its surface temperature is 7,750 K. HD 95086 is somewhat metal-deficient in comparison to the Sun, with a metallicity Fe/H index of −0.25 (~55%), and is much younger at an age of 13.3 million years. It was originally thought to be part of the Lower Centaurus-Crux association, until it was found using Gaia data that the star may be instead part of the Carina association.
Multiplicity surveys did not detect any stellar companions to HD 95086 as of 2013.
Nomenclature
The designation HD 95086 comes from the Henry Draper Catalogue.
In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project. The approved names, proposed by a team from Greece, were announced in June 2023. HD 95086 is named Aiolos after a Greek mythological figure, and its planet is named Levantes, from a modern Greek word referring to easterly Mediterranean winds.
Planetary system
In 2013, one planet, named HD 95086 b, was discovered on a wide orbit by direct imaging. The discovery was confirmed in 2014.
Besides the planet, the star is surrounded by a complex, relatively massive (0.5 ) debris disk, which may consist of up to four belts (Hot, Warm, Cold and Halo) separated by gaps. A small amount (1.4–13)×10−6 of gaseous carbon monoxide was detected in the outer disk, implying a recent collisional cascade followed by cometary activity of fresh debris.
References
Carina (constellation)
Pre-main-sequence stars
Planetary systems with one confirmed planet
Circumstellar disks
J10570301-6840023
CD-68 847
053524
095086
Aiolos | HD 95086 | [
"Astronomy"
] | 391 | [
"Carina (constellation)",
"Constellations"
] |
66,762,301 | https://en.wikipedia.org/wiki/Acoustic%20short%20circuit | An acoustic short circuit is a phenomenon in which sound waves interfere in such a way that both waves are canceled out. This occurs when the peak of one wave aligns with the trough of another, and the compressions and rarefactions of each wave neutralize each other. This occurs especially with improperly sealed loudspeakers, when the waves created on either side of the vibrating membrane are directly in opposition to each other.
Loudspeakers
An engineering problem in the construction of loudspeakers is how to ensure that the sounds waves created behind the membrane do not cancel out the ones created in front. This means that the two waves must not interact while they are still in their current phases. There are two ways to ensure that this does not happen: sealing and baffling.
Sealing
As the name implies, sealing encloses the sound waves coming from the back of the speaker so that they cannot reach the sound waves in front. Sealing makes for a better articulated, more accurate sound, and requires less accuracy in construction, but does not play low notes with as much intensity or range.
Baffling
Baffling is the process of piping away the sound waves from the back of the membrane and thus preventing the waves from interfering. The tube down which these waves travel, or the baffle, is generally made of a thick, non-resonant material. Longer baffles protect more bass frequencies from cancelling, but baffles are somewhat imperfect: they often reinforce waves of some frequencies and fail to fully prevent others from negatively interfering with their counterparts from the front of the membrane.
References
Acoustics
Waves | Acoustic short circuit | [
"Physics"
] | 330 | [
"Physical phenomena",
"Classical mechanics",
"Acoustics",
"Waves",
"Motion (physics)"
] |
77,042,503 | https://en.wikipedia.org/wiki/Dissociative%20adsorption | Dissociative adsorption is a process in which a molecule adsorbs onto a surface and simultaneously dissociates into two or more fragments. This process is the basis of many applications, particularly in heterogeneous catalysis reactions. The dissociation involves cleaving of the molecular bonds in the adsorbate, and formation of new bonds with the substrate.
Breaking the atomic bonds of the dissociating molecule requires a large amount of energy, thus dissociative adsorption is an example of chemisorption, where strong adsorbate-substrate bonds are created. These bonds can be atomic, ionic or metallic in nature. In contrast to dissociative adsorption, in molecular adsorption the adsorbate stays intact as it bonds with the surface. Often, a molecular adsorption state can act as a precursor in the adsorption process, after which the molecule can dissociate only after sufficient additional energy is available.
A dissociative adsorption process may be homolytic or heterolytic, depending on how the electrons participating in the molecular bond are divided in the dissociation process. In homolytic dissociative adsorption, electrons are divided evenly between the fragments, while in heterolytic dissociation, both electrons of a bond are transferred to one fragment.
Kinetic theory
In the Langmuir model
The Langmuir model of adsorption assumes
The maximum coverage is one adsorbate molecule per substrate site.
Independent and equivalent adsorption sites.
This model is the simplest useful approximation that still retains the dependence of the adsorption rate on the coverage, and in the simplest case, precursor states are not considered. For dissociative adsorption to be possible, each incident molecule requires n available adsorption sites, where n is the number of dissociated fragments. The probability of an incident molecule impacting a site with a valid configuration has the form
,
when the existing coverage is and the dissociative products are mobile on the surface. The order of the kinetics for the process is n. The order of kinetics has implications for the sticking coefficient
,
where denotes the initial sticking coefficient or the sticking coefficient at 0 coverage. The adsorption kinetics are given by
for (n=2),
where is the impinging flux of molecules on the surface. The shape of the coverage function over time is different for each kinetic order, so assuming desorption is negligible, dissociative adsorption for a system following the Langmuir model can be determined by monitoring the adsorption rate as a function of time under a constant impinging flux.
Precursor states
Often the adsorbing molecule does not dissociate directly upon contact with the surface, but is instead first bound to an intermediate precursor state. The molecule can then attempt to dissociate to the final state through fluctuations. The precursor molecules can be intrinsic, meaning they occupy an empty site, or extrinsic, meaning they are bound on top of an already occupied site. The energies of these states can also be different, resulting in different forms of the overall sticking coefficient . If extrinsic and intrinsic sites are assumed energetically equivalent and the adsorption rate to the precursor state is assumed to follow the Langmuir model, the following expression for the coverage dependence of the overall sticking coefficient is obtained:
,
where is the ratio between the rate constants of dissociation and desorption reactions of the precursor.
Temperature dependence
The behaviour of the sticking coefficient as a function of temperature is governed by the shape of the potential energy surface of adsorption. For the direct mechanism, the sticking coefficient is almost temperature independent, because for most systems . When a precursor state is involved, thermal fluctuations determine the probability of the weakly bound precursor either dissociating into the final state or escaping the surface. The initial sticking coefficient is related to the energy barrier for dissociation and desorption , and their rate constants and as
.
From this arises two distinct cases for the temperature dependence:
When , the sticking coefficient increases with substrate temperature. This is the case of activated adsorption
When , the sticking coefficient decreases as substrate temperature increases. This is the behaviour of non-activated adsorption.
By measuring the sticking coefficient at different temperatures, it is then possible to extract the value of .
Experimental techniques
The measurement of adsorption properties relies on controlling and measuring the surface coverage and conditions, including the substrate temperature, impinging molecular flux or partial pressure. To detect dissociation on the surface, additional techniques that can distinguish surface ordering due to the interaction of dissociated fragments, identify desorbed particles, determine the order of kinetics or measure the chemical bond energies of the adsorbed species are required. In many experiments, a combination of multiple methods that probe different surface properties is used to form a complete picture of the adsorbed species. Comparisons between the experimental adsorption energy and simulated energies for dissociative and molecular adsorption can also indicate the type of adsorption for a system
For measurement of adsorption isotherms, a controlled gas pressure and temperature determine the coverage when adsorption and desorption rates are in balance. The coverage can then be measured with various surface sensitive methods like AES or XPS. Often, the coverage can also be related to a change in the surface work function, which can enable faster measurements in otherwise challenging conditions. The shape of the isotherms is sensitive to the order of kinetics of the adsorption and desorption processes, and though the exact forms can be difficult to find, simulations have been used to find general functional forms for isotherms of dissociative adsorption for specific systems.
XPS is a surface sensitive method that allows the direct probing of the chemical bonds of the surface atoms, thus being capable of differentiating bond energies corresponding to intact molecules or dissociated fragments. A challenge with this method is that the incident photons can induce surface modifications that are difficult to separate from the effects to be measured. LEED patterns are often combined with other measurements to verify surface structure and recognize ordering of the adsorbates.
Temperature programmed desorption (TPD or TDS) can be used to measure the properties of desorption, namely the desorption energy, order of desorption kinetics and the initial surface coverage. The desorption order contains information about the mechanisms like recombination required for the desorption process. As TPD also measures the masses of the desorbed particles, it can be used to detect individually desorbed dissociated fragments or their different combinations. Presence of masses different from the original molecules, or the detection of additional desorption peaks with higher order kinetics can indicate that the adsorption is dissociative.
Modeling
Density functional theory (DFT) can be used to calculate the change in energy caused by the adsorption and dissociation of molecules. The activation energy is calculated as the highest energy point on the optimal molecular paths of the fragments as they transform from the initial molecular state to the dissociated state. This is the saddle point of the potential energy surface of the process.
Another approach for considering the stretching and dissociation of adsorbates is through the charge-transfer between the electron bands near the Fermi surface using molecular orbital (MO) theory. A strong charge transfer caused by overlap of unoccupied and occupied orbitals weakens the molecular bonds, which lowers or eliminates the barrier for dissociation. The charge transfer can be local or delocalized in terms of the substrate electrons, depending on which orbitals participate in the interaction. The simplest method used for approximating the electronic structure of systems using MO theory is Hartree-Fock self-consistent field, which can be extended to include electron correlations through various approximations.
Applications and examples
Water and transition metals
In atmospheric conditions, the adsorption of water and oxygen on transition metal surfaces is a well studied phenomenon. It has also been found that dissociated oxygen content on a surface lowers the activation energy for the dissociation of water, which on a clean metal surface can have a high barrier for dissociation. This is explained by the oxygen atoms binding with one hydrogen of the adsorbing water molecule to form an energetically favourable hydroxyl group. Likewise, molecular pre-adsorbed water can be used to lower the barrier for dissociation of oxygen that is needed in metal-catalyzed oxidation reactions. The relevant effects for this promoting role are hydrogen bonding between the water molecule and oxygen, and the electronic modification of the surface by the adsorbed water.
On clean close-packed surfaces of Ag, Au, Pt, Rh and Ni, dissociated oxygen prefers adsorption to hollow sites. Hydroxyl and molecular water prefers to adsorb on low coordination top sites, while the dissociated hydrogen atoms prefer hollow sites for most transition metals. A typical dissociation pathway on these metals is that as a top-site adsorbed molecule dissociates, at least one fragment migrates to a bridge or hollow site.
The formation and dissociation of water on transition metals like palladium has important applications in reactions for obtaining hydrogen and for the operation of proton-exchange membrane fuel cells, and much research has been conducted to understand the phenomenon. The rate-determining reaction for water formation is the creation of adsorbed OH. However, details of the specific adsorption sites and preferred reaction pathways for water formation have been difficult to determine. From kinetic Monte Carlo simulations combined with DFT calculations of the reaction energetics, it has been found that water formation on Pd(111) is dominated by step-edges through a combination of reactions:
O + H → OH
OO + H → OOH
OOH → OH + H
OH + OH → H2O + O
OH + H → H2O
At low temperatures and low relative pressure of H2, the dominant reaction path for hydroxyl group formation is the direct association of O and H, and the ratios of each reaction path vary significantly in different conditions.
Metal-catalyzed oxidation
The oxidation of carbon monoxide in catalytic converters utilizes a transition metal surface as a catalyst in the reaction
2CO + O2 → 2CO2.
This system has been extensively studied to minimize the emissions of toxic CO from internal combustion engines, and there is a trade-off in the preparation of the Pt catalyst surface between the dissociative adsorption of oxygen and the sticking of CO to the metal surface. A larger step density increases the dissociation of oxygen, but at the same time decreases the probability of CO oxidation. The optimal configuration for the reaction is with a CO on a flat terrace and a dissociated O at a step edge.
Hydrogen economy
The most prevalent method for hydrogen production, steam reforming, relies on transition metal catalysts which dissociatively adsorb the initial molecules of the reaction to form intermediates, which then can recombine to form gaseous hydrogen. Kinetic models of the possible dissociative adsorption paths have been used to simulate the properties of the reaction.
A method for hydrogen purification involves passing the gas through a thin film of Pd-Ag alloy between two gas vessels. The hydrogen gas dissociates on the surface of the film, after which the individual atoms are able to diffuse through the metal, and recombine to form a higher hydrogen content atmosphere inside the low-pressure receiving vessel.
A challenge with hydrogen storage and transport through conventional steel vessels is hydrogen-induced-cracking, where a hydrogen atoms enter the container walls through dissociative adsorption. If enough partial pressure builds up inside the material, this can cause cracks, blistering or embrittlement of the walls.
See also
Adsorption
Chemisorption
References
Surface science
Chemical physics
Physical chemistry
Catalysis | Dissociative adsorption | [
"Physics",
"Chemistry",
"Materials_science"
] | 2,473 | [
"Catalysis",
"Applied and interdisciplinary physics",
"Surface science",
"Condensed matter physics",
"nan",
"Chemical kinetics",
"Physical chemistry",
"Chemical physics"
] |
77,043,925 | https://en.wikipedia.org/wiki/Sclerococcum%20toensbergii | Sclerococcum toensbergii is a species of lichenicolous (lichen-dwelling) fungus in the family Sclerococcaceae. It is known from only a couple of collections made in the northwestern United States, and a collection in France. In the United States, it has been recorded on the bark-dwelling lichens Megalaria pulverea and Pertusaria carneopallida, while in France, it was found growing on Caloplaca cerina.
Taxonomy
Sclerococcum toensbergii was scientifically described as a new species in 2017 by the Belgian mycologist Paul Diederich. The type specimen was collected in the United States, specifically in Cowlitz County, Washington. It was collected on August 8, 1996, by the Norwegian lichenologist Tor Tønsberg. The type locality is located southwest of the summit of Mount St. Helens, at an elevation of . The lichen was found growing on the trunk of a red alder (Alnus rubra), specifically on Pertusaria carneopallida and accompanied by Phlyctis speirea. The species epithet honours Tønsberg, an "expert of corticolous, crustose lichens from the Northern Hemisphere".
Description
Sclerococcum toensbergii forms superficial, slightly convex structures known as , which are blackish and can be rounded, elongated, or irregular in shape. These sporodochia range from 100 to 300 μm in diameter and can sometimes merge together, often becoming poorly defined as mature conidia (asexual spores) spread around the conidiogenous (spore-producing) area. The vegetative hyphae of this fungus are pale to medium brown and are embedded within the host lichen's thallus, measuring 2 to 5 μm in diameter. The conidiophores, which are the spore-bearing structures, are grouped into dense . They are sparsely branched, pale to medium brown, and 2 to 3.5 μm thick.
The conidiogenous cells, where the conidia are produced, can be monoblastic (producing a single spore) or polyblastic (producing multiple spores). These cells are terminal (at the end of the conidiophores), integrated, brown, and range in shape from somewhat spherical to ellipsoid or elongated, making them hard to distinguish from other conidiophore cells. The conidia are produced singly and are rarely seen in chains. They are dry, roughly spherical or ellipsoid, medium to dark brown, and (divided into multiple cells), typically having 6 to 15 cells visible under a microscope. The conidia measure 12.5 to 23.0 μm in length and 7.7 to 17.5 μm in width, with a length-to-width ratio (Q) of 1.0 to 1.9. These conidia often spread around the sporodochia on the host thallus. Each conidial cell is subspherical to ellipsoid, measuring 3.5 to 6 μm in diameter, with septa (dividing walls) that are 0.5 to 1 μm thick and dark brown. The conidial walls are dark brown, 0.5 to 1 μm thick, smooth, or rarely rough.
Habitat, distribution, and ecology
At the time of its original publication, Sclerococcum toensbergii was known from two locations in Washington, USA. It was found growing on the bark-dwelling lichens Megalaria pulverea and Pertusaria carneopallida. These host lichens are asymptomatic of fungal infection, and do not show visible signs of damage. The Pertusaria carneopallida thallus observed, however, had fewer apothecia (fruiting bodies) than is typically seen in this species.
In 2021, the fungus was recorded from the southern Vosges, where it was found on Caloplaca cerina. This host grows at the base of Sorbus aucuparia (rowan) trees in areas characterized by Nardus grassland and dwarf shrub heathss with Vaccinium myrtillus (bilberry) and Calluna vulgaris (heather). This habitat is well-exposed to light and includes other lichens such as Lecidella elaeochroma and Rinodina malangica. The region experiences significant snowfall during the winter, which likely covers the whole community for extended periods. This locality is situated in the area with the highest precipitation levels in northeastern France. At an elevation of , the annual precipitation reaches 1900 mm. This high humidity is possibly relevant to the occurrence of Sclerococcum toensbergii. Similarly, in its Washington habitats, such as Mount St. Helens and the Olympic Peninsula, the annual precipitation is even higher, reaching 2500 mm.
References
Eurotiomycetes
Fungus species
Fungi described in 2017
Fungi of the United States
Taxa named by Paul Diederich
Lichenicolous fungi | Sclerococcum toensbergii | [
"Biology"
] | 1,052 | [
"Fungi",
"Fungus species"
] |
77,044,118 | https://en.wikipedia.org/wiki/Arthonia%20toensbergii | Arthonia toensbergii is a species of lichenicolous (lichen-dwelling) fungus in the family Arthoniaceae. It occurs in old-growth boreal rainforests in Norway, where it parasitises the lichen Mycoblastus affinis growing on trunks and branches of Norway spruce.
Taxonomy
The fungus was formally described as a new species in 2018 by the lichenologists Håkon Holien and Andreas Frisch. The type specimen was collected by Holien along the rover Svordka in Meldal (Sør-Trøndelag), where it was found growing on Picea abies twigs in an old spruce forest. The species epithet honours the Norwegian lichenologist Tor Tønsberg, on the occasion of his 70th birthday.
Molecular phylogenetics analysis shows that Arthonia toensbergii has a sister taxon relationship with the rare Scandinavian species Arthonia protoparmeliae, and that these two species form a clade that is itself sister to a clade containing Arthonia peltigera and Bryostigma muscigenum. All of these species are members of the so-called Bryostigma clade, which includes many lichenicolous Arthoniaceae.
Description
Arthonia toensbergii may cause pale brownish discolouration on the thallus of its host. The vegetative hyphae are thick-walled, measuring around 2–3 μm wide and 0.5–1.0 μm thick, and have specific chemical reactions (I+ vinose, KI+ pale blue). These hyphae are present in the host thallus near the ascomata. The ascomata form in small, non-aggregated colonies, with an irregularly rounded to short elliptical shape. They are adnate, moderately to strongly convex, and do not break through the host thallus. The ascomata are brownish-black to black with a finish and have a minutely roughened surface, measuring 0.07–0.15 mm in diameter and 0.07–0.1 mm in height.
The , , hymenium, and all feature a medium olivish-brown colouration. The is composed of compacted paraphysoidal hyphae, while the hymenium is and 35–40 μm tall, with distantly spaced asci. are loosely branched, netted, and embedded in a dense gelatinous matrix, with tips that widen and have dark brownish pigment or plaques. The asci are broadly (club-shaped), contain eight spores in irregular rows, and have a broadly triangular ocular chamber. The ascospores are hyaline (translucent), contain a single septum, and slipper-shaped, measuring around 12.6 by 4.7 μm on average. They are constricted at the septa, with thin walls and a narrow, smooth . No pycnidia were observed to occur in this species.
See also
List of Arthonia species
References
toensbergii
Fungus species
Fungi described in 2018
Fungi of Europe
Lichenicolous fungi
Taxa named by Andreas Frisch | Arthonia toensbergii | [
"Biology"
] | 653 | [
"Fungi",
"Fungus species"
] |
77,044,984 | https://en.wikipedia.org/wiki/TXS%201545-234 | TXS 1545-234 known as NVSS J154817-233701, is a radio galaxy located in the constellation Scorpius. It has a redshift of 2.755.
Characteristics
TXS 1545-234 is classified as a typical brighten Fanaroff-Riley Class II radio galaxy with double hot spots, making it a common phenomenon. This is caused by its radio jet changing direction by a small amount on a timescale less than the source. Other factors for having double hot spots in TXS 1545–234, are change of ejection axis from the galaxy's central engine, or by its jet-cloud interaction.
TXS 1545-234 is extremely luminous galaxy, with a space density of a few hundred times compared to today's galaxies. Moreover, it has a spatially extended waveband and a large rotation measure likely caused by magnetized, ionized gas. Like most high redshift radio galaxies (HzRG), TXS 1545-234 hosts a radio source featuring an ultra-deep spectrum (USS), making it a powerful tool to pinpoint distant galaxies. Such USS sources that were studied by researchers, found out there is a strong statistical relationship between its spectral index and the redshift.
In addition, TXS 1545-234 shows a large variety of properties. This includes the unexpected alignment between its ultraviolet and optical emission, the galaxy's radio structure as well as having an enormous gas halo present (> 100 kpc wide) showing strong Lyman-alpha emission lines.
The galaxy is known to have an inferred physical parameter of gas density, ionization parameter, and gas metallicity. However it shows no correlation with the radio power suggesting its ionization state is not affected significantly by the radio jet.
Observation
In the research done by Japanese researchers in 2022, TXS 1545-234 was one of the three galaxies selected out of the nine HzRGs studied by Matsuoka et al. (2009) for detection of metallicity in narrow-line regions. The other two were TN J0920-0712 and 4C +24.28. All of the three radio galaxies show a high S/N spectra with at least six emission lines with S/N > 5. According to researchers, they found there are N iv]λ1486, O iii]λ1663, and [Ne iv]λ2424 emission lines in these galaxies, which are weaker than C iv, He ii, and C iii] emission lines. Such of these, were carried out through observations using the FOcal Reducer and low dispersion Spectrograph 2, taken from the Very Large Telescope (VLT) in Chile, between 2005 October and 2006 October. From the observations they find the spectral resolution was R ~ 500, measured through usage of widths for sky emission lines.
From these results, all three radio galaxies show signs of high gas metallicity closer to or higher compared the solar metallicities (i.e., Z ≳ Z⊙), suggesting HzRGs are z ~ 3 are chemically maturing in the early universe, when the cosmic age was only ~2 Gyr, where the average and standard deviation of stellar mass in sample of galaxies such as 4C +23.46 and 4C +40.36 are (2.7 ± 1.3) × 1011 M⊙. The results are shown to consistent with some previous studies, but obtained with only fewer assumptions in the photoionization model.
References
Scorpius
Radio galaxies
2828571 | TXS 1545-234 | [
"Astronomy"
] | 735 | [
"Scorpius",
"Constellations"
] |
77,045,625 | https://en.wikipedia.org/wiki/Onboard%20passenger%20information%20system | Onboard passenger information system (PIS) is an integrated system for supplying passengers of public transport with information on their current journey through audiovisual information. The systems are installed on-board of public transport vehicles and provide ambient information to passengers both inside and outside of the vehicles. This is in contrast to a station/wayside passenger information system providing information to passengers on the platforms.
Overview
This system provides real-time information to passengers regarding various aspects of their journey, including schedules, station stops, route maps, safety instructions, and emergency procedures. The passenger information system has two modes of conveying information:
Automatic information – Information (audio/visual) that are triggered automatically by the passenger information system based on the current location, vehicle context, etc.
Manual information – Information (audio/visual) that are triggered or executed on-demand by on-board crew (e.g., driver, crew) or remote crew (from the operational control center)
Functions
The on-board passenger information system provides relevant information throughout the journey allowing passengers to make informed decisions about their travel plans, including transfers, connections, and arrival times.
PIS also enables the distribution of safety procedures.
The PIS streamlines public transport operations by disseminating information to passengers automatically. By reducing manual announcements and inquiries, the system frees up onboard staff to focus on other tasks.
PIS improves accessibility for passengers with disabilities or special needs by providing multi-channel information delivery, including audio announcements and visual displays, allowing passengers, regardless of their abilities, to access the information they need to navigate the journey independently.
History
In the 20th century, onboard passenger information relied solely on manual announcements by on-board conductors and staff using an analog audio system. Passengers were verbally informed about upcoming stations, arrival times, and other relevant information.
Mechanical display boards such as flip-disc display were used as destination signs. Other static signage, such as stickers, folders, etc., provided visual communication of public transport schedules, vehicle numbers, and other information.
The adoption of LED technology in the latter half of the 20th century modernized onboard communication in public transport. LED displays offered dynamic visual information and were energy-efficient for relaying real-time updates on station stop calling patterns and end destination information. Concurrently with the introduction of LED, digital audio systems began replacing traditional analog audio systems, offering clearer sound quality and the ability to broadcast pre-recorded messages. These systems enhanced accessibility for passengers because of the improved speech intelligibility of said digital audio systems.
The widespread adoption of Global Positioning System (GPS) technology in the 21st century enabled the integration of real-time location tracking into the on-board passenger information system. This allowed onboard systems to determine the train's position and inform passengers about upcoming stations.
The introduction of TFT displays added more visualization to on-board passenger information systems allowing a more graphical representation of the information. It allowed passengers to rely on a wide range of information, including route maps, images, videos, infomercials from the public transport agency, etc.
The proliferation of wireless connectivity, including Wi-Fi and cellular networks, has further enhanced the capabilities of the Passenger Information System. Whereas before the introduction of wireless connectivity, the passenger information system could only rely on local information available on-board of the train, since the introduction of wireless connectivity, passengers can access real-time updates from the passenger information system, improving the overall travel experience.
Components
Audio announcement system
Broadcasting of audio announcements through the speakers installed on-board of the vehicle. These announcements can be triggered by the automatic information system, providing auditory cues for passengers, including announcements of arrival in the next station, welcome messages, etc. The on-board crew can use specific handsets part of the audio announcement system to provide public address announcements to the passengers on top of the automatic information. Minimally consists of an amplifier, speakers, handsets (to perform public address).
Audio intercom system
Audio intercom system provides communication between the passengers and on-board staff. This allows for bidirectional communication between the on-board crew members (crew intercom) and the on-board crew members and passengers (passenger intercom). Minimally consists out of a handset (for crew interaction) and passenger communication units (for passenger interaction).
LED displays
Digital display screens inside the vehicle (to address passengers on-board) or outside the vehicle (to address passengers on the platform) displaying mainly textual information to passengers. They typically provide information on upcoming stations, end station, route number of the vehicle, etc. Compared to TFT displays, LED displays are better suited for use on the outside of the vehicle thanks to better contrast, higher readability with direct sunlight, etc.
TFT/LCD displays
Digital display screens inside the vehicle displaying textual and graphical information to passengers. They typically provide information on the current journey information (upcoming stations, arrival times, dynamic route maps, etc.) as well as infotainment information (advertisements, instruction videos, etc.)
Interactive touch screens
Installed in select (often locked) compartments of the vehicle and used by the driver/crew to control the Passenger Information System. Typical functionalities include starting the automatic announcements by entering a trip code, launching an ad-hoc pre-recorded announcement, consulting the current status of the PIS system, etc.
Controller
The central controller contains a software application that is responsible for driving the automatic information distribution across the different components of the onboard passenger information system.
Management software
Software application that runs off-board (often a Cloud-hosted solution) and that allows public transport operators to manage the PIS system in terms of configuration (e.g., changes to the PIS behavior), operational management (e.g., launching an ad-hoc announcement from the OCC and handle interactions with 3rd party systems (e.g., ITS for exchange of real-time information).
Characteristics
Audio
multi-branch to allow targeted announcements in different compartments of the vehicle (e.g., vestibule, passenger seating area, etc.)
automatic volume control based on ambient noise in the vehicle
LED
high-resolution, multi-color displays - possibility to display more than text
TFT
graphical visualization of information, dynamic line maps, geographical maps, etc.
Controller software
multilingual information distribution
real-time information from different sources
Interactions with other systems
TCMS/TCN – The Train Control & Management System is an on-board control system present on railway vehicles that has a central role in coordinating control and monitoring across disparate on-board systems. Typical interfaces between Passenger information systems and the TCMS are wheel-pulse information (for tracking purposes), GPS location, door status information, central time server, toilet status, etc.
APC – automated passenger counting systems are often integrated with the passenger information system to allow guiding passengers to the carriages with the least passengers present.
ITS/ITCS – the PIS systems often interface with ITS systems to retrieve real-time information regarding the current service (e.g., estimated arrival/departure times), connecting services (e.g., departure times/platforms of multi-modal services in the next station), service alerts (e.g., announcements regarding current and/or future disruptions).
CCTV – interfacing between the PIS system and on-board CCTV systems takes place to report events from the PIS system (e.g., passenger emergency call & location) to the CCTV system, visualization of CCTV streams on the PIS TFT displays, integration of the PIS HMI with the CCTV control functionalities, etc.
Challenges
Passenger Information Systems in public transport have some inherent challenges linked to the different life cycles of the systems (mechanical – electronic – software) in place. Regarding the mechanical vehicle bodies, there are examples of trains that have a lifetime of 30+ years, while the typical lifetime of hardware/electronic systems is between 5–10 years. The expectations of passengers and public transit agencies in terms of the functionalities of the Passenger information systems are evolving on a much higher pace, which can only be realized by tackling them in software. One of the primary challenges in on-board passenger information systems is synchronizing the disparate lifecycles of mechanical, electronic and software components. Coordinating maintenance schedules and upgrade cycles across these domains is essential to prevent disruptions.
References
External links
On-board Passenger Information System on televic.com
Transport systems
Transport infrastructure | Onboard passenger information system | [
"Physics",
"Technology"
] | 1,726 | [
"Physical systems",
"Transport",
"Transport infrastructure",
"Transport systems"
] |
77,047,046 | https://en.wikipedia.org/wiki/Plant%20soul | A plant soul is the religious philosophical concept that plants contain souls. Religions that recognize the existence of plant souls include Jainism and Manichaeism.
In Jainism
Jains believe that plants have souls (jīva) that experience only one sense, which is touch.
The Ācārāṅga Sūtra states that "plants ... and the rest of creation (experience) individually pleasure or displeasure, pain, great terror, and unhappiness" (1.1.6). In another excerpt from the Ācārāṅga Sūtra (1.1.5),
(Note that the pronouns "this" and "that" in Hermann Jacobi's original 1884 translation have been substituted with "men" and "plants".)
In Manichaeism
The Cologne Mani Codex contains stories showing that Manichaeans believed in the existence of sentient plant souls.
In Augustine of Hippo's Confessions (4.10), Augustine wrote that while he was a Manichaean, he believed that "a fig-tree wept when it was plucked, and the tree, its mother, shed milky tears".
Influence of Jainism on Manichaeism
Fynes (1996) argues that Jain ideas about the existence of plant souls were transmitted from Western Kshatrapa territories to Mesopotamia and then integrated into Manichaean beliefs.
See also
Plant perception (physiology)
Plant perception (paranormal)
Plant rights
References
Vitalism
Plants
Religious philosophical concepts
Jain philosophical concepts
Manichaeism
Souls | Plant soul | [
"Biology"
] | 303 | [
"Non-Darwinian evolution",
"Vitalism",
"Biology theories",
"Plants"
] |
77,047,612 | https://en.wikipedia.org/wiki/Dimerization%20of%20catharanthine%20and%20vindoline | Catharanthine and vindoline are terpenoid indole alkaloids naturally produced within the Madagascar periwinkle plant (Catharanthus roseus) whose dimerization produces the anti-cancer drugs vinblastine and vincristine. The precursor of catharanthine and vindoline is strictosidine, the common precursor of all indole alkaloids. The localization of catharanthine and vindoline within the plant tissue has been heavily studied in recent years with conflicting results. The dimerization of catharanthine and vindoline to form vinblastine and vincristine is catalyzed by a peroxidase and a reductase, and includes several intermediate compounds.
Origin
The compounds catharanthine and vindoline are naturally produced within the leaves of C. roseus plants. The C. roseus plant is a member of the Apocynaceae family, which are flowering plants that are found primarily in tropical and subtropical areas of the world. C. roseus are poisonous but medically useful plants due to the various terpenoid indole alkaloids (TIAs) they produce in their leaves, roots, and flowers. The precursor of catharanthine and vindoline is strictosidine, formed by the dimerization of tryptamine and secologanin. The reaction scheme to form catharanthine and vindoline involves more than 20 enzymes, of which not all have been isolated and characterized.
Localization
Catharanthine and vindoline are located predominately in the leaf tissue of C. roseus plants. In 1996-1998, three studies headed by Mariana Sottomayor from the University of Porto, Portugal localized catharanthine and vindoline in the vacuoles of the plant's cells. This claim was supported by a study in 2008. However, in 2015, a paper compiled data on the localization of TIAs within C. roseus cells from several studies reported that catharanthine is located in the upper epidermis cells of the leaf and vindoline is located in the laticifer cells of the leaf. This conclusion was both confirmed and contradicted by a recent study that used single-cell multi-omics to locate catharanthine and vindoline. This study, published in 2023, discovered the enzyme that produces catharanthine in epidermis cells and catharanthine molecules in idioblast cells. The study also discovered vindoline in idioblast cells.
Reaction scheme
The coupling reaction of catharanthine and vindoline begins with the activation of catharanthine by a peroxidase. This peroxidase was identified, characterized, and named CrPrx1 by the Costa group in 2008. CrPrx1 is dependent on the hydrogen peroxide naturally present in the leaf tissue to activate catharanthine. Once activated, catharanthine reacts with vindoline to form an iminium intermediate compound. A reductase reduces this compound to form alpha-3’,4’-anhydrovinblastine (AHVB). The reductase is theorized to be a tetrahydroalstonine synthase called THAS. AHVB reacts further to form vinblastine and vincristine, although this reaction scheme is yet to be fully understood.
Limiting factors
The dimerization of catharanthine and vindoline produces the anti-cancer drugs vinblastine and vincristine. The natural concentrations of catharanthine and vindoline are much higher than the concentrations of vinblastine and vincristine, which suggests that the reaction between catharanthine and vindoline is a rate-limiting step in the two anti-cancer drugs’ production. It has been theorized that the dimerization of catharanthine and vindoline is limited by multiple factors, two being the availability of hydrogen peroxide and the localization of the TIAs.
The synthesis of hydrogen peroxide is heavily regulated within the leaves of C. roseus, which means that there is a natural lack of hydrogen peroxide that may limit the amount of catharanthine activated by CrPrx1. The location of catharanthine and vindoline has been heavily investigated and debated, with studies finding the TIAs in the vacuoles, epidermis cells, idioblast cells, and laticifer cells. These studies show that some level of cellular separation between the alkaloids limits their ability to interact and react to produce vinblastine and vincristine.
References
Dimers (chemistry) | Dimerization of catharanthine and vindoline | [
"Chemistry",
"Materials_science"
] | 970 | [
"Dimers (chemistry)",
"Polymer chemistry"
] |
77,048,203 | https://en.wikipedia.org/wiki/Boon%20Ooi | Boon S. Ooi is a Malaysian–American academic researcher and a Professor of Electrical and Computer Engineering at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. He was faculty member at Nanyang Technological University (Singapore) from 1996 to 2000 and at Lehigh University (Pennsylvania, USA) from 2003 to 2009. He served as Director of KACST-Technology Innovation Center at KAUST from 2012 to 2020.
Education
Ooi received his early education in Kedah and Penang, Malaysia, before earning his BEng and PhD degrees in electronics and electrical engineering from the University of Glasgow in Scotland, UK, in 1992 and 1995, respectively.
Career
Research
His research lab focuses on the development of high-speed optoelectronics for optical fiber, and optical wireless communications. He has made significant contributions broadband emitters, and underwater photonics. Ooi has published more than 400 peer-reviewed journal papers and holds more than 40 issued US Patents. His research interests include high-speed optoelectronics, optical wireless communications, and distributed fiber optic sensors.
Professional Engagements
Ooi has served as Associate Editor of the Optics Express, Senior Editor of the IEEE Photonics Journal. Since 2022, he has been Editor-in-Chief of the IEEE Photonics Technology Letters. He has also served on IEEE Fellow Committee and SPIE Fellow Selection Committee.
Recognition
Ooi is the receipt of the Optica/OSA Sang Soo Lee Award, the Khalifa International Award, and several IEEE and OSA paper awards.
Ooi is a Fellow of the U.S. National Academy of Inventors (NAI), the Institute of Electrical and Electronics Engineers (IEEE), the Optica, the International Society for Optics and Photonics (SPIE), and the Institute of Physics.
References
Year of birth missing (living people)
Living people
Electrical engineers
Electrical engineering academics
Academic staff of King Abdullah University of Science and Technology
Fellows of the IEEE | Boon Ooi | [
"Engineering"
] | 395 | [
"Electrical engineering",
"Electrical engineers"
] |
77,051,129 | https://en.wikipedia.org/wiki/MRC%200406-244 | MRC 0406-244 also known as TN J0408-2418, is a radio galaxy producing an astrophysical jet, located in the constellation of Eridanus. At its redshift of 2.44, it is roughly ten billion light years from Earth.
Characteristics
MRC 0406-244 is one of the most powerful radio galaxies known date-to-date; it was studied extensively by the MRC/1 Jy radio source survey. MRC 0406-244 is also classified a Seyfert type 2 galaxy, with a complex morphology featuring several components, including a point source with an extended nebular and continuum emission. Moreover, it contains an ultra-deep spectrum radio source (USS).
Host galaxy
The host galaxy of MRC 0406-244 is a dusty obscured massive early-type galaxy with a star formation of (M⋆ ~ 1011 M⊙). The galaxy also has a stellar disc, within the range of 3.5 to 8.2 kpc which is similar to coeval star-forming galaxies, which is found to be smooth.
Galaxy merger
From recent Hubble Space Telescope (HST) images, researchers have found several bright clumps with figure-of-eight shapes elongated along the radio jet axis of MRC 0406–244. Further images reveal there is a spatially resolved continuum. It is associated with its southeastern component that is aligned with the radio axis, with a complex morphology, including a double nucleus and tidal tail features. This suggests of a tidal origin, meaning a recent galaxy merger has taken place. It is believed that galaxy merger plays a dominant role in which its supermassive black hole is fueled. Signs show the black hole inside the center of MRC 0406–244, is growing at an exponential rate of hundreds to thousands of solar masses per year, so as the luminosity, turning it into a quasar.
Observation of MRC 0406-244
According from HST and ground-based multiwavelength observations of MRC 0406–244, researchers found there are two distinct components, aligned with its radio source axis. One of them has the red optical-to-IR and blue ultraviolet colors, making it a characteristic of radio galaxies, while the other is red in all colors. From the Lyα image, a nebula in MRC 0406-244 is found to be 3'' × 5'' extent, confined to the range of azimuth angles with respect to the nucleus of 60° to either side. Another component is also found extending northwest with similar morphology seen in the HST images.
Researchers also found the long axis of the Lyman-alpha emission that is 130° east of north in MRC 0406–244, aligns with the radio source. They found out, the total Ly flux is 1.2 × 10−14 ergs s−1 cm−2, equivalent to a luminosity of 1 × 1045 ergs s−1. 1 40% of this flux is within the 25 × 35 area that is measured in the spectrum. The peak surface brightness of the Ly emission is found to be 9.0 × 10−16 ergs s−1 cm−2 arcsec−2, and emission is detected down to a level of 1.5 × 10−16 ergs s−1 cm−2 arcsec−2.
Radio Properties
A triple radio source found in MRC 0406–244, is amongst the most power radio sources known according to researchers. They noted that the radio source reaches up to luminosity of 1.2 × 1036 ergs s−1 Hz−1 at 1 GHz and radiating at 6.3 × 1045 ergs s−1 between 100 MHz and 100 GHz. This extends over 84 kpc between the hot spots of MRC 0406–244, which found to be steep and strongly curved. The spectral index of the radio source changes from 1.21 at 1 GHz to 1.49 at 16 GHz in the rest frame to flux densities at several frequencies between 408 MHz and 8.44 GHz. This radio core contains a spectral index of 0.80 ± 0.18 (between 4.7 and 8.4 GHz, observed) that contributes the total emission at 15 GHz at 2%.
The two radio lobes in MRC 0406-244 are notable for their degree of asymmetry. Given the asymmetries in arm length and the spectral indices in powerful sources, they are both related both intrinsic asymmetries and light travel-time differences. From the correlation between emission-line and radio asymmetries in other 3CR radio galaxies, this suggests dominance of environmental effects, which cosmic dust plays a main role in correlation of optical and radio asymmetries.
Gas and dust beyond MRC 0406-244
Further observations from researchers found, that nebular and continuum ultraviolet light extends up to 25 kpc from the nucleus of the galaxy. This is six times more than the length of the minor axis in the direction of the radio jets. Both extended components are shown to contribute to the alignment effect given their distribution is biconical along the jet axis. The dust at similarly large radii is known to exist, given the diffuse blue continuum is dust-scattered from active galactic nucleus light or from dust-reddened young stars. The dust must had probably originated in the galaxy, hence the outflow of both metal-rich gas and dust is important for enriching the intracluster medium.
The nebular gas can be driven out from MRC 0406–244 in two ways. One, either through expanding starburst bubbles. Two, by overpressurized cocoons of material that is surrounding the expanding radio jets. The dust grains are likely destroyed when interacting with powerful radio jets, so they instead transported by radiation pressure or supernovae induced winds.
Dust in the intergalactic medium has theorized for a long time, but detected only recently. From the study published by Ménard et al. (2010), it is suggested half of the cosmic dust lies within galaxies, whilst the other half is expelled to the intergalactic medium. The extended light in MRC 0406−244 allows researchers, a rare opportunity to observe the dust in the midst of leaving the galaxy. As the host galaxy of MRC 0406−244 does not have different characteristics compared to other massive star-forming galaxies, it is possible that many highly star-forming galaxies lying at a similar redshift also expels out similar amounts of dust in bipolar outflows. The dust remains invisible unless it gets illuminated through sufficiently bright active galactic nuclei or through feedback driven star formations. If such dusty outflows in MRC 0406-244 is common, then researchers are expected to see ultraviolet-bright emission along the minor axis of stacked images of starbursting active galactic nuclei.
References
Radio galaxies
Seyfert galaxies
Eridanus (constellation)
2823818
Interacting galaxies
Active galaxies | MRC 0406-244 | [
"Astronomy"
] | 1,448 | [
"Eridanus (constellation)",
"Constellations"
] |
77,051,679 | https://en.wikipedia.org/wiki/National%20Aerospace%20Standard | National Aerospace Standards (NAS) are U.S. industry standards for the aerospace industry. They are created and maintained by the Aerospace Industries Association (AIA). The Federal Aviation Administration recognizes National Aerospace Standards as "traditional standards" for the purposes of parts approval.
The primary AIA committee responsible for developing standards is the National Aerospace Standards Committee (NASC). Since 1938, NASC has developed more than 2,600 standards for aerospace fasteners and other mechanical parts. Personnel from the defense services, Defense Industrial Supply Center and Defense Electronics Supply Center participate in the preparation of NAS standards, and liaison is maintained with the FAA, NASA, AIA Canada, and the airlines. NAS standards are developed on the basis of user requirements, although coordination is accomplished with suppliers and other materially affected interests.
References
Standards of the United States
Aerospace | National Aerospace Standard | [
"Physics"
] | 170 | [
"Spacetime",
"Space",
"Aerospace"
] |
77,052,134 | https://en.wikipedia.org/wiki/Kata%20Kov%C3%A1cs%20and%20Tom%20O%27Doherty | Kata Kovács and Tom O’Doherty (often also referred to by the stylised abbreviation KKTO) are an artist duo, primarily known for working with sound and duration. They live and work in Berlin, Germany.
About
Kata Kovács is originally from Kecskemét, Hungary, and studied dance in Budapest; Tom O’Doherty is originally from Dublin, Ireland, where he studied literature. After meeting in Berlin, they began to work together in 2011. Their initial collaborations were on a series of performances involving the acoustic traces created by movement scores, which were presented at Sophiensæle, ausland, Uferstudios, Montag Modus, and other venues in the city. Their work has subsequently been presented at Los Angeles County Museum of Art, Serralves Museum, MNAC Chiado, Ars Electronica, Casino Luxembourg, and Issue Project Room, among others.
The duo's work incorporates elements of durational and time-based art, minimalist movement, and electroacoustic music and sound. They assert a curiosity about “processes, sounds, and movements that come close to imperceptibility, and the ways in which this material can be transformed through repetition, patterning, layering, and archiving.”
Notable works
In 2017, the duo presented the “sound and extraterrestrial radio installation,” Signal Tide, at LACMA, Los Angeles. This work, which was undertaken in collaboration with David Bryant of Godspeed You! Black Emperor, involved receiving live signals from an abandoned satellite, the LES-1, as it orbited the earth above the site of the work, and combining the sound produced from these transmissions with music derived from sacred harp singing. The work was presented outdoors, beside the museum's Pavilion for Japanese Art, and was centered around a line of custom-made overhead speakers. The work became ‘activated’ every three hours — the time it took for the satellite to orbit the earth and return to the sky above Los Angeles. An audio piece based on the work was subsequently commissioned by the museum as part of their LACMA@home series in 2020.
In 2016, Kata Kovács and Tom O’Doherty began their long-durational installation work, Minute/Year. This automated work produces a one-minute-long audio recording every day, with each recording acoustically layered over the one which has preceded it, in a process which has been ongoing for over eight years to date. The work alters location every year, and in 2024 it is located in Olin Library at Wesleyan University. The first seven years of the work were presented at a retrospective at Halfsister Berlin in 2023.
The 2016 work, Afterglow, was presented as part of the closing event for Digital in Berlin's Kiezsalon series at Musikbrauerei. The work was an installation in which all the concerts in the 2016 Kiezsalon series were recorded, and then replayed in overlapping fragments, in the giant basement space of the Musikbrauerei, “evoking recognisable parts of past events, now juxtaposed with each other and situated in a radically different environment.” The work included excerpts from live performances by Christina Vantzou, Laraaji, Janek Schaefer, and others.
Other activities
Kata Kovács and Tom O’Doherty are represented by Hošek Contemporary. Both are also active in other musical and artistic collaborations: Kata Kovács is a member of the improvisation ensemble Vrouw, Tom O’Doherty has worked with Paula Matthusen and has exhibited photography. Both were members of Fake Company with Kathleen Hermesdorf.
External links
Kata Kovács and Tom O’Doherty
Minute/Year
References
Art duos
Sound artists
Sound art
Women sound artists
Living people
Electroacoustic music composers
Minimalist composers
Conceptual artists
Multimedia artists
Year of birth missing (living people) | Kata Kovács and Tom O'Doherty | [
"Technology"
] | 797 | [
"Multimedia",
"Multimedia artists"
] |
77,052,373 | https://en.wikipedia.org/wiki/Nonlinear%20dispersion%20relation | A nonlinear dispersion relation (NDR) is a dispersion relation that assigns the correct phase velocity to a nonlinear wave structure.
As an example of how diverse and intricate the underlying description can be, we deal with plane electrostatic wave structures which propagate with in a collisionless plasma. Such structures are ubiquitous, for example in the magnetosphere of the Earth, in fusion reactors, or in a laboratory setting. Correct means that this must be done according to the governing equations, in this case the Vlasov-Poisson system, and the conditions prevailing in the plasma during the wave formation process. This means that special attention must be paid to the particle trapping processes acting on the resonant electrons and ions, which requires phase space analyses. Since the latter is stochastic, transient and rather filamentary in nature, the entire dynamic trapping process eludes mathematical treatment, so that it can be adequately taken into account “only” in the asymptotic, quiet regime of wave generation, when the structure is close to equilibrium.
This is where the pseudo-potential method in the version of Schamel, also known as Schamel method, comes into play, which is an alternative to the method described by Bernstein, Greene and Kruskal.
In the Schamel method the Vlasov equations for the species involved are first solved and only in the second step Poisson's equation to ensure self-consistency.
The Schamel method is generally considered the preferred method because it is best suited to describing the immense diversity of electrostatic structures, including their phase velocities. These structures are also known under Bernstein–Greene–Kruskal modes or phase space electron and ion holes, or double layers, respectively.
With the S method, the distribution functions for electrons and ions , which solve the corresponding time-independent Vlasov equation,
and , respectively,
are described as functions of the constants of motion. Thereby the unperturbed plasma conditions are adequately taken into account. Here and
are the single particle energies of electrons and ions, respectively ; and are the signs of the velocity of untrapped electrons and ions, respectively. Normalized quantities have been used, and it is assumed that , where is the amplitude of the structure.
Of particular interest is the range in phase space where particles are trapped in the potential wave trough. This area is (partially) filled via the stochastic particle dynamics during the previous creation process and is expressed and parameterized by so-called trapping scenarios.
In the second step, Poisson's equation, , where are the corresponding densities obtained by velocity integration of and , is integrated whereby the pseudo-potential is introduced. The result is , which represents the pseudo-energy. In
the points stand for the different trapping parameters . Integration of the pseudo-energy results in , which yields by inversion the desired . In these expressions the canonical form of is used already.
There are, however, two further trapping parameters
, which are missing in the canonical pseudo-potential. In its extended previous version they fell victim to the necessary constraint that the gradient of the potential vanishes at its maximum. This requirement is
and leads to the term in question, the nonlinear dispersion relation (NDR). It allows the phase speed of the structure to be determined in terms of the other parameters and to eliminate from to obtain the canonical . Due to the central role, the two expressions and are playing, the Schamel method is sometimes also called Schamel's pseudo-potential method (SPP method). For more information, see references 1 and 2.
A typical example for the canonical pseudo-potential and the NDR is given by
and by
where and , respectively.
These expressions are valid for a current-carrying, thermal background plasma described by Maxwellians (with a drift between electrons and ions) and for the presence of the perturbative trapping scenarios , s=e,i.
A well known example is the Thumb-Teardrop dispersion relation, which is valid for single harmonic waves and is given as a simplified version of the NDR above with zero trapping parameters and a vanishing drift. It reads
.
It has been thoroughly discussed in but mistakenly as a linear dispersion relation.
A plot of for a more general type of structures, the periodic cnoidal electron holes, is presented in Fig 1. for the case and immobile ions () showing the effect of the electron trapping parameter for positive and negative values.
Finally, it should be mentioned that an NDR has the nice property that it remains valid even if the potential
has an undisclosed form, i.e. can no longer be described by mathematically known functions.
References
Plasma physics equations | Nonlinear dispersion relation | [
"Physics"
] | 960 | [
"Equations of physics",
"Plasma physics equations"
] |
77,052,648 | https://en.wikipedia.org/wiki/Begonia%20%C3%97%20hiemalis | Begonia × hiemalis, the elatior begonia or Reiger begonia, is an artificial hybrid species of flowering plant in the family Begoniaceae. Its parents are Begonia socotrana and Begonia × tuberhybrida (itself a hybrid of multiple species). Hybridization efforts began in 1881, with the first cultivar named 'John Heal'. The 'Elatior' cultivar debuted in 1906, and beginning in 1950 Otto Rieger issued many new, disease-resistant cultivars, such that people began to call the species "elatior" or "Rieger" begonias. In addition to their typically doubled flowers which come in every color except blue, they are valued for their tendency to bloom in fall and winter, and in fact nearly year-round.
References
hiemalis
Hybrid plants
Ornamental plants
Plants described in 1933 | Begonia × hiemalis | [
"Biology"
] | 180 | [
"Hybrid plants",
"Plants",
"Hybrid organisms"
] |
77,052,711 | https://en.wikipedia.org/wiki/List%20of%20resolved%20circumstellar%20disks | This is a list of circumstellar disks that have published resolved images. Many of them are protoplanetary disks or debris disks. Only some are transitional disks between protoplanetary and debris. A few disks in this list are circumbinary disks.
List of large disks
This list contains disks with a diameter larger or equal to 2arcseconds and is sorted after their diameter in arcsecs.
List of small disks
There are hundreds of small resolved disks. This list only contains a selection of disks with d<2 arcsec.
References
Lists of astronomical objects
Circumstellar disks | List of resolved circumstellar disks | [
"Astronomy"
] | 126 | [
"Astronomy-related lists",
"Astronomical objects",
"Lists of astronomical objects"
] |
77,054,288 | https://en.wikipedia.org/wiki/JADES-GS-z14-0 | JADES-GS-z14-0 is a high-redshift Lyman-Break galaxy in the constellation Fornax that was discovered in 2024 using NIRcam as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. It has a redshift of 14.32, making it the most distant galaxy and astronomical object ever discovered.
Discovery
JADES-GS-z14-0 was observed using the James Webb Space Telescope's Near-Infrared Spectrograph (NIRSpec) in 2024, and it measured a redshift of 14.32, placing the galaxy's formation at an estimated 290 million years after the Big Bang. Its age, size, and luminosity added to a growing body of evidence that current theories of early star and galaxy formation are incomplete.
Characteristics
JADES-GS-z14-0 is 1600 light years wide and very luminous. Spectroscopic analysis revealed the presence of strong ionized gas emissions, including hydrogen and oxygen.
Further observations
The initial identification of JADES-GS-z14-0 came from imaging data obtained with JWST’s Near-Infrared Camera (NIRCam). The high-redshift hypothesis was confirmed through multiple spectroscopic observations with NIRSpec. Additionally, observations using JWST's Mid-Infrared Instrument (MIRI) detected the galaxy at longer wavelengths, which support the extreme distance at which JADES-GS-z14-0 is located.
See also
JADES-GS-z13-0, the former record-holder for furthest galaxy
List of the most distant astronomical objects
References
Galaxies
Discoveries by the James Webb Space Telescope
Fornax
20240530
Galaxies discovered in 2024 | JADES-GS-z14-0 | [
"Astronomy"
] | 360 | [
"Fornax",
"Constellations"
] |
71,074,489 | https://en.wikipedia.org/wiki/Heteroclinic%20channels | Heteroclinic channels are ensembles of trajectories that can connect saddle equilibrium points in phase space. Dynamical systems and their associated phase spaces can be used to describe natural phenomena in mathematical terms; heteroclinic channels, and the cycles (or orbits) that they produce, are features in phase space that can be designed to occupy specific locations in that space. Heteroclinic channels move trajectories from one equilibrium point to another. More formally, a heteroclinic channel is a region in phase space in which nearby trajectories are drawn closer and closer to one unique limiting trajectory, the heteroclinic orbit. Equilibria connected by heteroclinic trajectories form heteroclinic cycles and cycles can be connected to form heteroclinic networks. Heteroclinic cycles and networks naturally appear in a number of applications, such as fluid dynamics, population dynamics, and neural dynamics. In addition, dynamical systems are often used as methods for robotic control. In particular, for robotic control, the equilibrium points can correspond to robotic states, and the heteroclinic channels can provide smooth methods for switching from state to state.
Overview
Heteroclinic channels (or heteroclinic orbits) are building blocks for a subset of dynamical systems that are built around connected saddle equilibrium points. Homoclinic channels/orbits join a single equilibrium point to itself, whereas heteroclinic channels join two different saddle equilibrium points in phase space. The connection is formed from the unstable manifold of the first saddle (“pushing away” from that point) to the stable manifold of the next saddle point (“pulling towards” this point). Combining at least three saddle equilibria in this way produces a heteroclinic cycle, and multiple heteroclinic cycles can be connected into heteroclinic networks.
Heteroclinic channels have both spatial and temporal features in phase space. Spatial because they affect trajectories within a certain region around themselves, and temporal because the parameters of a heteroclinic channel affect how much time a trajectory spends along that channel (or more specifically, how much time it spends around one of the saddle points). The transient nature of heteroclinic channels is important for describing their “switching” nature. That is, some neighborhood around each equilibrium point can be defined as a separate state, and the heteroclinic channel itself presents a method of switching sequentially between these states.
Heteroclinic "switching" is an important descriptor for natural phenomena, especially in neural dynamics. It has also been used as an approach for designing robotic control methods which cycle between states, whether those states are pre-defined behaviors or transient states that lead to larger behaviors.
History
The mathematical image described above – a series of states with a functional mechanism for switching between them – also describes a phenomenon known as winnerless competition (WLC). Winnerless competition describes the switching phenomenon between two competitive states and was identified by Busse & Heikes in 1980 when they were investigating the change of phases in a convection cycle. However, the transient dynamics of WLC are widely agreed to first have been presented by Alfred J. Lotka, who first developed the concept to describe autocatalytic chemical reactions in 1910 and then developed an extended version in 1925 to describe ecological predator-prey relationships. In 1926, Vito Volterra independently published the same set of equations with a focus on mathematical biology, especially multi-species interactions. These equations, now known as the Lotka-Volterra equations, are widely used as a mathematical model to describe transient heteroclinic switching dynamics.
Heteroclinic cycles which describe the transition between at least three states were first described by May & Leonard in 1975. They identified a special case of the Lotka-Volterra equations for population dynamics . The re-emergence of heteroclinic cycles and the increased ability to do numerical computations as compared to the period of Lotka and Volterra, prompted a resurgence of interest in heteroclinic channels, cycles, and networks as mathematical models for transient sequential dynamics.
Heteroclinic channels have become models for neural dynamics. An example is Laurent et al. (2001) who described the neural responses of fish and insects to olfactory stimuli as a WLC system, where each stimulus and its response could be identified as a separate state within the space. The responses could be modeled in this way because of their spatial and temporal properties, which aligned with the spatiotemporal nature of WLC. Rabinovich et al. (2001) & Afraimovich et al. (2004) used WLC networks (via the Fitzhugh-Nagumo & Lotka-Volterra models, respectively) to connect the mathematical concept of stable heteroclinic channels (SHCs) to transient neural dynamics more generally, particularly other sensory processes and more abstract neural connections. Rabinovich et al. (2008) expanded this idea to larger cognitive dynamic systems, and large-scale brain networks. Stable heteroclinic channels have also been used to model neuromechanical systems. The feeding structures and associated feeding processes (stages of swallowing) of marine mollusks have been analyzed using heteroclinic channels.
Biological models have always been a source of inspiration for roboticists, especially those interested in robotic control. Since robotic control requires defining and sequencing the physical actions of the robot, models of neural dynamics can be very useful. An example of this can be found in central pattern generators, which are widely used for rhythmic robotic motion. Heteroclinic channels have been used to replicate central pattern generators for robot control. Similarly, dynamic movement primitives, another common robotic motion control system, have been adapted and made more flexible by using heteroclinic channels. In more practical applications, stable heteroclinic channels have been directly used in the control of several biologically-inspired robots
Concepts
Dynamical systems
A dynamical system is a rule or set of rules that describe the evolution of a state (or a system of states) in time. The set of all possible states is called the state space. The phase space is the state space of a continuous system. Dynamical systems describe the state over time with mathematical equations, often ordinary differential equations. The current state at a particular time can be plotted as a point in phase space. The set of points over time can be plotted as a trajectory.
Stability
A heteroclinic channel itself can be asymptotically stable. That is, any point near the vicinity of the channel is attracted to the heteroclinic cycle at the core of the channel. Both heteroclinic channels and cycles can be robust (or structurally stable) if, within a given parameter range, they maintain a given behavior; however, this is not required.
Stochasticity
Noise is one input into a heteroclinic system to move it from one equilibrium to the next. The reason is that noise (or some other stochasticity) disturbs the system enough to move it into the vicinity of the next saddle equilibrium point in the sequence. The amount of noise required is inversely proportional to the “attractiveness” of the saddle points; the more attractive the stable part of the saddle is to the system state, the longer the trajectory will linger in its vicinity, and the more noise will be required to move the system’s state off of that attractive equilibrium point. There are also other ways of moving between the equilibrium points including parametric changes, or using sensory feedback.
Control theory
Control theory, in robotics, deals with the use of dynamical systems to control robotic systems. The goal of robotic control is to perform precise, coordinated actions using physical actuators in response to sensor input. Dynamical systems can be used to drive the robot to a desired state (or set of states) using sensor input to minimize actuator errors.
Mathematical definition
An equilibrium point in a dynamical system is a solution to the system of differential equations describing a trajectory that does not change with time. Equilibrium points can be described by their stability, which are often determined by the eigenvalues of the system’s Jacobian matrix. In general, the eigenvalues of a saddle point have non-zero real parts, at least one of the real parts is positive and at least one of the real parts is negative. Any eigenvalue with a negative real value indicates a stable manifold of the saddle which attracts trajectories, whereas any eigenvalue with a positive real value indicates the unstable manifold of the saddle which repels trajectories.
Phase space definition (from Heteroclinic orbit)
Let be the ordinary differential equation describing a continuous dynamical system. If there are equilibria at and , then a solution is a heteroclinic connection from to if
as
and
as
This implies that the connection is contained in the stable manifold of and the unstable manifold of .
Neural dynamics examples
Neural dynamics are the non-linear dynamics that describe neural processes, from single neurons to cognitive processes and large-scale neural systems.
Lotka-Volterra model
This model was first presented independently by Alfred J. Lotka for autocatalytic chemical reactions and then again for biological species in competition by Vito Volterra from a mathematical biology perspective. Originally, this model was only considered for two species: the two chemical species in the reaction, or a predator-prey situation in a shared environment.
The original equations were based on the logistic population equation, which is popularly used in ecology.
where is the size or concentration of a species at a given time, is the growth rate and is the carrying capacity of that species.
Lotka incorporated a term for the interaction between species and, with some generalization, the series of equations can be written as follows:
In this definition, is the size or concentration of the -th species and is the total number of species. The interaction between each species is described by the matrix .
May-Leonard expansion
May and Leonard expanded the Lotka-Volterra equations by investigating the system in which three species interact with each other (i.e., ). They found that for a system in which each equilibrium point is a saddle with an dimensional stable manifold, and the unstable manifold connects the points sequentially, the equation above can be re-written as follows:
Explicitly for , this becomes
where the coupling matrix, , is given by
In this model, the stability of the saddle equilibria can be easily determined. The stability requirements for the formation of a stable heteroclinic cycle are with either or .
It was noted in this work that the system never asymptotically reaches any of the equilibrium points, but the amount of time the trajectory spends at each equilibrium point increases with time. In ecological terms, this suggests that a single population would eventually “beat out” the other two. May & Leonard noted that this is not a practical result in biology (and also see).
Winnerless Competition framework
The “Winnerless Competition” framework (suggested by Laurent et al.) allowed a single neuron and/or a collection of synchronized neurons to be encoded between "on" and "off". Laurent et al. investigated olfaction in fish and insects, particularly olfactory reception, and some of the postsynaptic structures in the odor sensory system. They found that the processing (or encoding) of perceived odors occurred over at least three timescales: fast, intermediate, and slow. They posited that an odor encoding system should be reproducible, which requires it to be insensitive to (or rapidly forget) any initial state. This is only possible if the dynamical system is strongly dissipative, that is, it settles on a state quickly and is insensitive to internal noise. Conversely, a useful odor encoding system should be sensitive to small variations in input, which requires the system to be active. An active system uses external sources to allow small variations in initial states to grow with time. The winnerless competition framework allowed a single neuron (or node) to encode a stimulus (the “fast” timescale), or many stimuli could be encoded via stimulus-specific trajectories (the “slow” timescale).
The winnerless competition system was described by
where and characterize the activities of stimulus-specific groups and , respectively, is the number of neurons being simulated, characterizes the strength of inhibition by and (i.e., their interactions with each other), and is the current input by a stimulus to .
Winnerless competition required that the inhibitory connections in the matrix were asymmetrical and cyclic. For example, for , if then , and .
Overall, this description produces a heteroclinic channel composed of several heteroclinic orbits (trajectories).
Transient neural dynamics
Sensory encoding via heteroclinic orbits (which are facilitated by heteroclinic channels) as described by Laurent et al. was extrapolated beyond the olfactory system. Rabinovich et al. explored winnerless competition as a spatiotemporal dynamical system corresponding to the activity of specific neurons or groups of neurons. They identified the added stimulus as the factor that would drive a trajectory from one node along the channel to the next. Without it, the system would reduce to a steady state in which one neuron (or neuronal group) was active whereas the others were quiescent.
Afraimovich et al. also developed winnerless competition using connected saddle points in phase space as a model for transient, sequential neural activity. They outlined how the saddle points should be defined, the conditions for heteroclinic connections between them and the conditions for heteroclinic sequence stability. They performed numerical simulations of the dynamics of a network with N = 50 neurons and used Gaussian noise as the external input. They found that the movement of a trajectory along each connection was initiated by the noise, and the speed of switching from one saddle to the next depended on the noise level.
Cognitive dynamics
The sequential switching property of stable heteroclinic channels has been expanded to describe higher-level transient cognitive dynamics, particularly sequential decision making. Rabinovich et al. first introduced this idea by applying the sequential switching that characterizes stable heteroclinic channels to the sequential decision making process seen in a fixed time game. The player takes sequential actions in a changing environment to maximize some reward. For a fixed time game, in order to maximize the reward, the player must encounter as many decision states as possible. This means that within a fixed amount of time, the trajectory must pass in the vicinity of as many saddle points, or nodes, as possible. When the trajectory reached the vicinity of a saddle point, a decision-making function was applied.
The reward was maximized by choosing appropriate system parameters. One of these was a decision-making rule that corresponded to the fastest motion away from the saddle, which was the shortest time to reach the next saddle. Additionally, there was an optimal level of additive noise; the noise was high enough that the trajectory could move away from each saddle quickly, but not so high that the trajectory would be directed off the cycle entirely.
A major point of this work was that, without significant external stimulus, the player was likely to find one of two extremes: ending decision-making quickly or reaching a cycle that runs through the entire allotted time. Behaviorally, this cycle translates to habit formation (on a cognitive level) and is sensitive to external stimuli that can change the trajectory’s direction at any time.
Rabinovich & Varona described sequential memory in a similar way. They also introduced “chunking”, which describes how the brain groups sequential information items into chunks at different hierarchical levels. They used stable heteroclinic channels as a framework for building these chunks into high level heteroclinic networks.
Neuromechanical models
Heteroclinic channels have also been used as a model for neuromechanical systems in animals, particularly the feeding structures in marine mollusks. Shaw et al. (2015) investigated potential models for the feeding behavior of Aplysia californica. They found that heteroclinic channels could more accurately match features of actual experimental data than other models such as limit cycles. Lyttle et al. (2017) showed that both the heteroclinic model and the limit cycle model of the Aplysia californica’s feeding system grant different advantages and disadvantages, such as robustness to perturbations and flexibility to inputs. They also showed that a reasonable model of the animal’s behavior could be made by switching between these modes, heteroclinic and limit cycle, using external sensory input, providing a dynamical basis for understanding both robustness and flexibility in motor systems.
Robotic control examples
Mathematical expansions of the framework are required for robotic control applications.
For higher dimensional systems, the connection/inhibition matrix can be generalized as:
or formulations similar to this.
Appropriate saddle values must be assigned to make the system dissipative. The strength of the saddle can be characterized by its two largest eigenvalues: the single unstable eigenvalue, , and the weakest stable eigenvalue, . The saddle value of the -th node can be defined as
If , the -th node is dissipative and stable, and if the entire cycle will be stable.
SHCs for biologically inspired robotic control
SHCs have been used directly to control robots, particularly biologically-inspired robotic systems. SHCs have also been used to adapt existing robot control frameworks. In both instances, the special properties of SHCs were used to improve the associated control tasks. Some examples include integrated contact sensing to modulate the additive SHC noise, a combined Gaussian Mixture Model to inform SHC "switching", a central pattern generator which was adapted to be temporally sensitive, and a modified control framework which has an intuitive visualization property.
Contact sensing for additive noise modulation
SHCs make it possible to use sensory feedback for rapid choices in a high degree-of-freedom robotic system. For example, Daltorio et al. used SHCs as a controller for the simulated locomotion of a worm-like robot in a pipe. The robot's structure consisted of 12 actuated body segments, each with one degree of freedom: segment length. Each segment coupled its height to the length such that as the length decreased, the height increased. This structure was used to simulate peristaltic locomotion, as the segments’ actuation was coordinated to form a peristaltic wave down the robot, with each segment contracting one after the other down the robot body.
For this system, each body segment was associated with a saddle point in the SHC system. The multi-dimensional connection matrix was constructed so that each point inhibited its neighbors except the point immediately after it. This asymmetry caused the active SHC node to move “backwards” down the robot structure, while the body moved forward.
The controller was tested in multiple pipe-shaped paths where contact sensors on the robot could provide information on the environment. Contact sensing information was used to modulate the noise added to the system, which in turn allowed the activation sequence to be altered. This was key for highly coordinated movement across all segments.
Gaussian mixture model to inform "switching"
SHCs can be used to inform the switching among complex configurations. Petrič et al. used a combined Gaussian Mixture Model (GMM) and SHC system to control a spinal exoskeleton. The exoskeleton was designed as a quasi-passive system that physically supports the user to different degrees depending on the current pose or movement of the user. Different functional poses/movements were identified as the nodes within the SHC system. GMMs were used to indicate what the additive inputs for each SHC node should be, which would drive the system from one pose to the next.
Temporally sensitive central pattern generator
SHCs have been used as an alternative to central pattern generators for robotic control. Horchler et al. used SHCs to produce an oscillator whose behavior near each node could be manipulated using system parameters: additive noise and saddle values. This produced a cyclic controller that could spend more time at a particular node when needed. The controller's responsiveness to external input was demonstrated by pausing and resetting the cycle using additive noise.
Intuitive visualization property
Rouse & Daltorio replaced the underlying attractor points of dynamic movement primitives, another biologically-inspired robotic control method, with the saddle points of SHCs. This adaptive framework maintained the stability of the system. Additionally, it provided a visualization property which allowed the user to intuitively place saddle points in phase space to match a desired trajectory in the task space.
See also
Dynamical systems
Saddle equilibrium points
Heteroclinic networks
Heteroclinic orbits
Lotka-Volterra equations
Neuromechanical systems
Control theory
Biologically-inspired robotic systems
Limit cycles
References
Further reading
J. Lotka, Elements of Physical Biology. Baltimore: Williams and Wilkins, 1925.
M. Krupa, “Robust Heteroclinic Cycles,” J. Nonlinear Sci, vol. 7, pp. 129–176, 1997.
M. I. Rabinovich and M. K. Muezzinoglu, “Mutual Emotion-Cognition Dynamics,” Association for the Advancement of Artificial Intelligence, 07-Sep-2009. [Online]. Available: . [Accessed: 02-Nov-2021].
Antonio Palacios (2007) Heteroclinic cycles. Scholarpedia, 2(1):2352.
Eugene M. Izhikevich (2007) Equilibrium. Scholarpedia, 2(10):2014.
James Meiss (2007) Dynamical systems. Scholarpedia, 2(2):1629.
Frank Hoppensteadt (2006) Predator-prey model. Scholarpedia, 1(10):1563.
Randall D. Beer (2009) Biologically inspired robotics. Scholarpedia, 4(4):1531.
External links
Most viewed “heteroclinic” articles on Frontiers Media.
A Matlab Toolbox for the Simulation, Analysis and Design of Continuous Dynamical Systems Based on Networks of Stable Heteroclinic Channels (SHCs)
Code for the simulations and figures from Lyttle et al. (2017)
Dynamical systems | Heteroclinic channels | [
"Physics",
"Mathematics"
] | 4,667 | [
"Mechanics",
"Dynamical systems"
] |
71,078,367 | https://en.wikipedia.org/wiki/TMEM104 | Transmembrane protein 104 (TMEM104) is a protein that in humans is encoded by the TMEM104 gene. The aliases of TMEM104 are FLJ00021 and FLJ20255. Humans have a 163,255 base pair long gene coding sequence, 4703 base pair long mRNA, and 496 amino acid long protein sequence. In Eukaryotes, the TMEM104 gene is conserved.
Gene
Location
TMEM104 is located on human chromosome 17 at the locus 17q25.1. TMEM104 is located between the genes NAT9 and GRIN2C.
Transcripts
There are 7 main transcription variants: isoform 1, isoform 2, variant X1 - X5. TMEM104 is predicted to have a promoter region 150 base pairs upstream of the start of transcription. The promoter region of Homo sapien TMEM104 compared to other organisms is very unconserved. It was hard to find anything outside of Mammalia species and most were found under Primates.
Tissue expression
In most human tissues, TMEM104 has a modest expression level (25–50th percentile), relative to all human proteins, according to RNA-seq data.
Subcelluar expression
The protein has been located primarily in the plasma membrane and less so found in nucleus.
Immunochemistry Data
Thermofisher claims that it exhibits significant nuclear and cytoplasmic positivity in glandular cells. With the aid of a TMEM104 polyclonal antibody, the samples were probed.
Protein
TMEM104 variant 1 protein is 496 amino acids in length. TMEM104 is a secreted protein that is overexpressed in Adrenal. TMEM104 is a phenylalanine enriched and glutamine poor protein.
Characteristics
TMEM104 has an isoelectric point of 6.8 and a molecular weight of 55.7 kdaltons. It is predicted to have between nine and eleven transmembrane domains, making it a transmembrane protein.
Post Translation Modifications
The post-translational modifications N-glycosylation, sulfonation, and phosphorylation are among those predicted for TMEM104.
Tertiary structure
TMEM104 has a tertiary structure with alpha helices and beta sheets.
Interaction
TMEM104 has been shown to interact with CASKIN2, TMEM94, TOMM6, SYNGR3, SYTL5, B3GNT8, NTRK3, C15orf39, and PPSIG.
Homology
Ortholog
TMEM104 has no paralogs. TMEM protein is found mostly in Eukaryotes.
The orthologs in the following table were discovered through BLAST searches. Although by no means exhaustive, this list demonstrates the enormous variety of organisms that include TMEM104 orthologs.
References
Uncharacterized proteins | TMEM104 | [
"Biology"
] | 639 | [
"Protein classification",
"Uncharacterized proteins"
] |
71,079,573 | https://en.wikipedia.org/wiki/Markov%20chain%20tree%20theorem | In the mathematical theory of Markov chains, the Markov chain tree theorem is an expression for the stationary distribution of a Markov chain with finitely many states. It sums up terms for the rooted spanning trees of the Markov chain, with a positive combination for each tree. The Markov chain tree theorem is closely related to Kirchhoff's theorem on counting the spanning trees of a graph, from which it can be derived. It was first stated by , for certain Markov chains arising in thermodynamics, and proved in full generality by , motivated by an application in limited-memory estimation of the probability of a biased coin.
A finite Markov chain consists of a finite set of states, and a transition probability for changing from state to state , such that for each state the outgoing transition probabilities sum to one. From an initial choice of state (which turns out to be irrelevant to this problem), each successive state is chosen at random according to the transition probabilities from the previous state. A Markov chain is said to be irreducible when every state can reach every other state through some sequence of transitions, and aperiodic if, for every state, the possible numbers of steps in sequences that start and end in that state have greatest common divisor one. An irreducible and aperiodic Markov chain necessarily has a stationary distribution, a probability distribution on its states that describes the probability of being on a given state after many steps, regardless of the initial choice of state.
The Markov chain tree theorem considers spanning trees for the states of the Markov chain, defined to be trees, directed toward a designated root, in which all directed edges are valid transitions of the given Markov chain. If a transition from state to state has transition probability , then a tree with edge set is defined to have weight equal to the product of its transition probabilities:
Let denote the set of all spanning trees having state at their root. Then, according to the Markov chain tree theorem, the stationary probability for state is proportional to the sum of the weights of the trees rooted at . That is,
where the normalizing constant is the sum of over all spanning trees.
References
Markov processes
Spanning tree | Markov chain tree theorem | [
"Mathematics"
] | 456 | [
"Theorems about stochastic processes",
"Theorems in probability theory"
] |
71,081,884 | https://en.wikipedia.org/wiki/Richard%20P.%20Simmons | Richard P. Simmons (born May 3, 1931) is an American metallurgist.
Life and career
Simmons was born on May 3, 1931. He attended Massachusetts Institute of Technology (MIT) in 1949. He became a metallurgist at the Allegheny Ludlum Steel corporation in Pittsburgh. He then worked for other steel companies before returning to become the chief executive of Allegheny, taking it public and then leading a management buyout. Having become wealthy, he then created a variety of endowments at MIT.
Simmons was also chairman of the Pittsburgh Symphony Orchestra between 1989 and 1997. He returned as chairman in 2003 until his retirement in 2015.
References
1931 births
Living people
Metallurgists | Richard P. Simmons | [
"Chemistry",
"Materials_science"
] | 141 | [
"Metallurgists",
"Metallurgy"
] |
71,082,281 | https://en.wikipedia.org/wiki/Judit%20Puskas | Judit Puskas is a Distinguished Ohio State University professor noted as co-inventor of the polymer used on the Taxus-brand coronary stent. She is the first woman to win the Charles Goodyear Medal, the highest honor conferred by the American Chemical Society's Rubber Division. Her research focuses on polymer engineering for breast reconstruction in cancer treatment, green polymer chemistry, biomimetic processes, biomaterials, living polymerization, polymerization mechanisms and kinetics, thermoplastic elastomers, polymer structure/property relationships, and polymer-bio interfaces.
Education
She received her Ph.D. in Plastics and Rubber Technology/M.E. Organic and Biochemical Engineering from the Technical University of Budapest in 1985. She completed a postdoc under Joseph Kennedy at the University of Akron.
Career
1989–1996 – Research Scientist at Bayer
1996–2004 – Professor at University of Western Ontario
2004–2018 – Professor at University of Akron
2019–present Professor at Ohio State University
Awards
2017 – Charles Goodyear Medal of the Rubber Division of the American Chemical Society
References
Living people
Polymer scientists and engineers
Budapest University of Technology and Economics alumni
Academic staff of the University of Western Ontario
University of Akron faculty
Ohio State University faculty
Year of birth missing (living people)
Women materials scientists and engineers | Judit Puskas | [
"Chemistry",
"Materials_science",
"Technology"
] | 263 | [
"Polymer scientists and engineers",
"Physical chemists",
"Materials scientists and engineers",
"Polymer chemistry",
"Women materials scientists and engineers",
"Women in science and technology"
] |
71,083,305 | https://en.wikipedia.org/wiki/Quantum%20boomerang%20effect | The quantum boomerang effect is a quantum mechanical phenomenon whereby wavepackets launched through disordered media return, on average, to their starting points, as a consequence of Anderson localization and the inherent symmetries of the system. At early times, the initial parity asymmetry of the nonzero momentum leads to asymmetric behavior: nonzero displacement of the wavepackets from their origin. At long times, inherent time-reversal symmetry and the confining effects of Anderson localization lead to correspondingly symmetric behavior: both zero final velocity and zero final displacement.
History
In 1958, Philip W. Anderson introduced the eponymous model of disordered lattices which exhibits localization, the confinement of the electrons' probability distributions within some small volume. In other words, if a wavepacket were dropped into a disordered medium, it would spread out initially but then approach some maximum range. On the macroscopic scale, the transport properties of the lattice are reduced as a result of localization, turning what might have been a conductor into an insulator. Modern condensed matter models continue to study disorder as an important feature of real, imperfect materials.
In 2019, theorists considered the behavior of a wavepacket not merely dropped, but actively launched through a disordered medium with some initial nonzero momentum, predicting that the wavepacket's center of mass would asymptotically return to the origin at long times — the quantum boomerang effect. Shortly after, quantum simulation experiments in cold atom settings confirmed this prediction
by simulating the quantum kicked rotor, a model that maps to the Anderson model of disordered lattices.
Description
Consider a wavepacket with initial momentum which evolves in the general Hamiltonian of a Gaussian, uncorrelated, disordered medium:
where and , and the overbar notation indicates an average over all possible realizations of the disorder.
The classical Boltzmann equation predicts that this wavepacket should slow down and localize at some new point — namely, the terminus of its mean free path. However, when accounting for the quantum mechanical effects of localization and time-reversal symmetry (or some other unitary or antiunitary symmetry), the probability density distribution exhibits off-diagonal, oscillatory elements in its eigenbasis expansion that decay at long times, leaving behind only diagonal elements independent of the sign of the initial momentum. Since the direction of the launch does not matter at long times, the wavepacket must return to the origin.
The same destructive interference argument used to justify Anderson localization applies to the quantum boomerang. The Ehrenfest theorem states that the variance (i.e. the spread) of the wavepacket evolves thus:
where the use of the Wigner function allows the final approximation of the particle distribution into two populations of positive and negative velocities, with centers of mass denoted
A path contributing to at some time must have negative momentum by definition; since every part of the wavepacket originated at the same positive momentum behavior, this path from the origin to and from initial momentum to final momentum can be time-reversed and translated to create another path from back to the origin with the same initial and final momenta. This second, time-reversed path is equally weighted in the calculation of and ultimately results in . The same logic does not apply to because there is no initial population in the momentum state . Thus, the wavepacket variance only has the first term:
This yields long-time behavior
where and are the scattering mean free path and scattering mean free time, respectively. The exact form of the boomerang can be approximated using the diagonal Padé approximants extracted from a series expansion derived with the Berezinskii diagrammatic technique.
References
Condensed matter physics
Quantum mechanics | Quantum boomerang effect | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 775 | [
"Theoretical physics",
"Phases of matter",
"Quantum mechanics",
"Materials science",
"Condensed matter physics",
"Matter"
] |
71,083,368 | https://en.wikipedia.org/wiki/Alberto%20Mansion | The Alberto Mansion is a historic house in Biñan, Laguna, Philippines.
History
The house was built around the 1800s and was owned by Jose Alberto Alonzo. The house is noted for its connection to the family of José Rizal. Alonzo is the father of Rizal's mother Teodora Alonso Realonda. Biñan is where Realonda would spend her teenage years and where she would meet Rizal's father Francisco Mercado who lived in a house nearby. The property would later be passed down through several generations.
The house also had other tenants such as Cipriano Alberto, who was Biñan mayor in 1790 and 1802; his son Lorenzo, who was also mayor in 1844; and grandson Jose, who was the Philippines' representative to the Spanish cortes.
In 2009 or 2010, the house was reportedly sold to Gerry Acuzar by Gerardo Alberto, a fifth-generation descendant of the Jose Alberto Alonzo. Acuzar is the owner of Las Casas Filipinas de Acuzar, a resort in Bagac, Bataan known for incorporating heritage structures from other parts of the country. The Alonzo clan allowed for the house's full relocation to the Bataan resort but the move was opposed by the city government of Biñan. The Biñan government also offered to buy the property for but the owner reportedly declined the offer of the local government.
The Biñan city government also issued an ordinance in 2011 declaring the Alberto Mansion a heritage site. On October 21, 2012, the roof of the building collapsed, which is suspected to be as a result of dismantling the interior for transfer to the Acuzar resort in Bataan. The Biñan council also sought for the National Historical Commission of the Philippines to declare the building a National Historical Landmark to allow for its expropriation. Along with the Biñan local government, the United Artists for Cultural Conservation and Development, City of Biñan Inc. (UACCD) has advocated for the restoration of the house.
The expropriation process was delayed as the house owners negotiated with the Biñan government. The city government later alleged that owners were also having talks to another party to have the property leased for a Jollibee fast food outlet. The Biñan government then filed a expropriation case in May 2017. The expropriation was granted by the local court in the same year. The house was later restored; to as close as the original design as possible by the same construction firm which developed the Acuzar resort.
Architecture and design
The Alberto Mansion is a two-storey building with an area of . The building is an example of a Bahay na Bato. According to the Biñan city government the structure was around 10 percent of the original prior to the 2012 roof collapse. It is situated in front of the Sentrong Pangkultura ng Biñan, which is also the former Biñan Municipal Hall.
References
Bahay na bato
Buildings and structures in Biñan
Controversies in the Philippines
Architectural controversies | Alberto Mansion | [
"Engineering"
] | 613 | [
"Architectural controversies",
"Architecture"
] |
71,086,629 | https://en.wikipedia.org/wiki/Pre-modern%20conceptions%20of%20whiteness | The description of populations as white in reference to their skin colour predates and is distinct from the race categories constructed from the 17th century onward. Coloured terminology is occasionally found in Graeco-Roman ethnography and other ancient and medieval sources, but these societies did not have any notion of a white or pan-European race. In Graeco-Roman society whiteness was a somatic norm, although this norm could be rejected and it did not coincide with any system of discrimination or colour prejudice. Historically, before the late modern period, cultures outside of Europe and North America, such as those in the Middle East and China, employed concepts of whiteness. Eventually these were progressively marginalised and replaced by the European form of racialised whiteness. Whiteness has no enduring "true essence", but instead is a social construct that is dependent on differing societal, geographic, and historical meanings. Scholarship on race distinguishes the modern concept from pre-modern descriptions, which focused on skin colour, complexion and other physical traits.
Background
Beginning with the rise of agricultural economies and the increasing stratification of societies around the world approximately 6000 years ago, light skin came to be increasingly associated with higher social status. Because lower status individuals were typically required to participate in arduous outdoor toil, dark skin began to be associated with lower social status in agricultural societies around the world. Over time whiteness became associated with happiness, success, freedom from outdoor toil, and even spiritual purity. In the ancient and medieval societies of Europe, Asia, and North Africa, light skin, especially among women, came to be a sign of living a privileged lifestyle, having noble ancestry, and also became an indicator of beauty.
Fertile Crescent
Mesopotamia
In ancient Mesopotamia healthy skin colours were described as sāmu ("ruddy" or "reddish") or peṣû ("white") while ill-health was associated with the skin colour arqu ("pale-brown" or "yellow"), a reference to jaundice. Peṣû was descended from the Proto-Semitic word f/pṣḥ, which was related to whiteness and brightness. The word sāmu would also be used to refer to red hair, either dyed or natural, with natural red hair being associated with the Eurasian Steppe. For Akkadians, peṣû might also be used to refer to medical conditions such as albinism or severe anaemia, or a woman's fair complexion. In contrast the Akkadian word ṣalmu ("black") would be used to describe people with dark skin, such as the Nubian pharaoh of Egypt's 25th Dynasty. Along with brown eyes, blue eyes or namru ("dazzling(-blue)), are also referred to in Mesopotamian writings.
Ancient Egypt
According to anthropologist Nina Jablonski:
The Ancient Egyptian (New Kingdom) funerary text known as the Book of Gates distinguishes "four groups" in a procession. These are the "red-brown" Egyptians, the "pale" Levantine and Canaanite peoples or "Asiatics", the "black" "Nubians" and the "fair-skinned Libyans". The Egyptians are depicted as considerably darker-skinned than the Levantines (persons from what is now Lebanon, Israel, Palestine and Jordan) and Libyans, but considerably lighter than the Nubians (modern Sudan). Sex differences in skin colour were also depicted in Egyptian art, with women being depicted as noticeably lighter skinned than men. Men would be painted dark reddish-brown, while women could be painted "white, tan, cream, or yellow". Classical archaeologists typically ascribe this divergence to the differing lifestyles of men and women. According to Charles Freeman, depictions of women with light skin suggested a high status, and were a "sign that a woman did not have to work in the sun". As with other Mediterranean cultures, light skin came to be the feminine ideal in Egyptian art.
The Levant
Ancient Greeks labeled the Phoenicians, and Levantines in general, as Phoinike (), a word derived from the Greek work Phoinos, meaning "ruddy", possibly in reference to the skin colour of Ancient Levantines. In the Hebrew Bible, figures such as Esau and King David are described as "ruddy". According to scholar David M. Goldenberg, the ancient Israelites and Judean peoples preferred women with a "fair complexion". This preference is established in both biblical and post-biblical literature. For example, The Genesis Apocryphon describes Sarah as being "beautiful" in "her whiteness." A later scenario is written about by one of the Tannaim in which a potential groom refuses to marry a woman who he believes to be "ugly" and "black" (sḥehorah) until he finds out she is in fact "beautiful" and "white" (levanah). In the Song of Songs a woman praises her lover for being "white and ruddy" while she is described as "clear as the moon".
Goldenberg wrote:
A rabbinic text commenting on the skin diseases mentioned in the Bible (Leviticus, chs. 13–14; Deut 24:8), states: "An intensely bright white spot [baheret] appears faint on the very light-skinned [germani], while a faint spot appears bright on the very dark-skinned [kushi]. Rabbi Ishmael said: 'The Jewsmay I be like an expiatory sacrifice for them [an expression of love]are like the boxwood tree [eshkeroae], neither black nor white, but in between.'"2 This statement records a second-century (R. Ishmael) perception that the skin color of Jews is midway between black and white.3 More precisely it is light brown, the color of the boxwood tree. This early perception of the intermediate, light-brown shade of the Jewish complexion is corroborated by a number of papyri from the Ptolemaic period in Egypt that describe the complexion of various Jews as "honey-colored."
India
The nature of skin colour and its role in the Indian caste system is strongly contested. According to the Indian sociologist G. S. Ghurye the groups mentioned in the Vedas, the Arya and Dasa, were distinguished by their skin colour or "varna" with the Arya being associated with a fair complexions and the Dasa being associated with dark complexions. Similarly, sociologist James Alfred Aho states that skin colour was used as a marker for what eventually became the caste system. Anthropologist Arthur Helweg states that the initial basis for the varna system was skin colour. Bengali scholar Jayantanuja Bandyopadhyaya records that in the Rigveda, the god Indra distributed the lands of the conquered Dasa to the "white-coloured" Arya. As such, Bandyopadhyaya characterises the conflict between the "white-skinned" Arya and "black-skinned" Anarya, or non-Aryans, as having racial overtones. The Indian Marxist historian D. D. Kosambi, wrote that the darker skin of the Dasyu "contrasted with the lighter skin-colour of the newcomers [Aryans]." The Mahabhashya, Ṛgveda, and Gopatha Brahmana contain, according to Kenneth A.R. Kennedy, references to Brahmins with "white skins and red or yellow hair." Per David Lorenzen, there are some references in later Vedic literature that suggest the Brahmin and Vaishya castes are referred to as "white or fair".
The Indian scholars Varsha Ayyar and Lalit Khandare assert that colourism, or discrimination based on skin pigmentation, has existed in India since pre-colonial times, predating any Eurocentric concepts of whiteness. Similarly, the scholar Nina Kullrich submits that references to colour in Indian culture predate European colonialism and that although racism and colourism are linked together, they are not equivalent, with a desire for whiteness being a part of Indian culture that is distinguished from European concepts.
Others, such as Michael Witzel, state that the Rigveda uses "black skin" as a metaphor for irreligiosity. The Indian historian Romila Thapar states that skin colour differences are more likely to be symbolic descriptors. Kadira Pethiyagoda also states that while varna does literally mean colour, and was used to classify groups of people and express differences, recent scholarship suggests these terms were symbolic.
Ancient Greece
As with Ancient Egyptians, Mycenaean Greeks and Minoans generally depicted women with pale or white skin and men with tanned skin. Men with pale or light skin, leukochrōs (λευκόχρως, "white-skinned") could be considered weak and effeminate by Ancient Greek writers such as Plato and Aristotle. According to Aristotle, "Those whose skin is too dark are cowardly: witness Egyptians and the Ethiopians. Those whose skin is too light are equally cowardly: witness women. The skin colour typical of the courageous should be halfway between the two." Similarly, Xenophon of Athens describes Persian prisoners of war as "white-skinned because they were never without their clothing, and soft and unused to toil because they always rode in carriages" and states that Greek soldiers as a result believed "that the war would be in no way different from having to fight with women." In the Republic, Plato writes: "the swarthy are of manly aspect, the white are children of the gods, divinely fair".
In Greek literature women including goddesses such as Hera and Aphrodite and mortals such as Penelope, Andromache, and Nausicaa can be described as leukōlenos (, "white-armed"). Athena is described as having blondish or brownish hair (xanthe ()) and blue, green, or grey eyes. Contrarily male warriors like Odysseus were usually described as having brown or bronzed skin, unless attention was being brought to skin that was vulnerable to injury in battle. Greek visual art usually showed women as white, much lighter than the typical male. As a goddess of beauty, Aphrodite was usually given very white skin in both graphic and textual art. Whiteness was generally seen as a desirable part of femininity in Ancient Greek culture. The anonymous ancient Greek text the 'Alexander Romance' describes an exchange of letters between Alexander the Great and Queen Candace of Meroe (in Nubia), in which the queen writes: "Do not despise us for the colour of our skin. In our souls we are brighter than the whitest of your people."
Classicist James H. Dee states "the Greeks do not describe themselves as 'White people'or as anything else because they had no regular word in their colour vocabulary for themselves." According to the historian Nell Irvin Painter, people's skin colour did not carry useful meaning; what mattered is where they lived.
Herodotus described the Scythian Budini as having deep blue eyes and bright red hair and the Egyptians – quite like the Colchians – as (, "dark-skinned") and curly-haired. He also gives the possibly first reference to the common Greek name of the tribes living south of Egypt, otherwise known as Nubians, which was (). Later Xenophanes of Colophon described the Aethiopians as black and snub-nosed and the Thracians as having red hair and blue eyes. In his description of the Scythians, Hippocrates states that the cold weather "burns their white skin and turns it ruddy."
The 2nd century Anatolian Greek sophist Polemon of Laodicea advocated a view of ancient physiognomy which attributed variations in skin and hair colour to the actions of the Sun. An anonymous 4th century Latin treatise, based on the work of Polemon, describes several stereotypes, including some related to skin colour, such as the claim that light-skinned "Northern" people are "courageous and bold and so forth". The Arabic translations of Polemon similarly includes white skin in a list of several traits held by Greeks of Hellenic or Ionian descent. In the Physiognomy Polemon describes ancient Greeks as follows:
"The pure Greek is of medium stature, between tall and short, broad and weak. He is of erect posture, beautiful in face and appearance, white in colour, mixed with red, medium in flesh, with medium palms and elbows, alert, quick to learn, neither small nor large of head, in his neck thickness and strength. His hair is soft and red, with some curliness and some waviness on account of its lankness. In his face there is squareness, in his lip slimness, and his nose is pointed and evenly proportioned. His eyes are moist, bluish-black, very mobile, and very luminous. This is the description of the pure Greek."
A 4th century text by the physician Adamantius, which is largely based on Polemon's work, includes a similar description of the Greeks.
Ancient Rome
The Caribbean scholar Mervyn C. Alleyne states that the Romans used the term candidus, a neutral term for white, to refer to themselves. Romans would also use the term albus, which referred to the physical phenomenon of whiteness, to refer to their skin colour. Vitruvius used candidus in his description for populations of northern Europe that "have huge bodies and are white in colour". The Roman writer Julius Firmicus Maternus would contrast the Germaniae candidi (white Germans) with 'Ethiopians', while Pliny spoke of Northern Europeans having candida atque glacialis cutis or "white and frosty skins". According to the Roman geographers Pomponius Mela and Pliny, a group of white Ethiopians (leukaethiopes), possibly a reference to lighter-skinned Berbers, inhabited the North African interior. The term candidus was later replaced during the Germanic invasion of Rome by the term blancus, which served a similar purpose, and which has survived in modern languages such as French blanc, Spanish blanco, Portuguese branco, and Italian bianco. Like candidus, blancus, was a neutral term used for Caucasian peoples.As with the ancient Greeks, the ancient Romans saw whiteness as an important part of feminine beauty. For example, in Virgil's Aeneid, Dido, the Phoenician queen of Carthage, and lover of Aeneas, is described as candida or "white". Virgil also refers to the goddess Venus as having "snow white arms". The Carthaginian poet Luxorius wrote disparagingly of the skin colour of Ethiopian women while praising the colour white as the ideal colour for women.
References to skin colour appear in Roman literature beyond references to women. Being unable to tell the difference between a white person and a black person was a common Roman idiom, used metaphorically to establish a state of ignorance. These idioms are attested in the writings of Cicero and Catullus. In the second of his Satires, the Roman satirist Juvenal writes "let the straight-legged man laugh at the club-footed man, the white man (albus) at the black (aethiops)", although many varying translations are possible. In his fictional dialogue Hermotimus, the Hellenised Syrian satirist Lucian speculates on whether an isolated Ethiopian would assume out of hand that there are no "white or yellow" men on Earth. The Roman author Appian describes Roman soldiers encountering an Ethiopian when going out to fight, "and as they considered this a bad omen they immediately cut him in pieces." A similar event is recorded in the Historia Augusta, in which the emperor Septimius Severus is enraged by presence of an Ethiopian soldier, "troubled as he was by the man’s ominous colour".
Several Roman authors, such as Tacitus and Suetonius, expressed concerns in their writings about Roman "blood purity" as Roman citizens from outside of Roman Italy increased in number. Neither author, however, suggested that the naturalisation of new citizens should stop, only that manumissions (freeing slaves) and grants of citizenship should be less frequent. Their concerns of blood purity did not match modern ideas of race or ethnicity, and had little to do with features such as skin colour or physical appearance. According to Lloyd A. Thompson terms such as Aethiop, which Romans used for black people, carried no social implications, although “blacks in Roman society were at all times largely slave-immigrants or progeny of such immigrants" and "their numbers were always small”. Though phenotype-related stereotypes certainly existed in Ancient Rome, inherited physical characteristics were typically not relevant to social status. The historian Frank M. Snowden has stated that people who looked different from the typical Mediterranean populace, such as black people, were not excluded from any profession and there are no records of stigmas or biases against mixed race relationships. The main dividing social differences in Ancient Rome were not based on physical features, but rather on differences in class or rank. Romans practised slavery extensively, but slaves in Ancient Rome were part of various different ethnic groups and were not enslaved because of their ethnic affiliation. According to the English historian Emma Dench, it was "notoriously difficult to detect slaves by their appearance" in Ancient Rome. In contrast the classicist Michele George writes that "The somatic differences of Blacks reinforced their visible difference from Italian aesthetic norms and facilitated a connection with slaves, the proverbial aliens in Roman thought. Thus, although their numbers among the slave population were relatively small, the presence of Blacks in Roman art is dominated by the slave context." Classicist Kyle Harper notes a third-century inscription from coastal Tunisia which preserves "a vicious invective against the presence of black slaves", referring to them as "scum" and "demons" with "black bodies" and "awful faces". According to the historian David Goldenberg, Roman objections to Black people were, "for the most part, based on physical characteristics of the body, their hair, lips, nose, but especially their skin color.… The Greco-Roman distaste for the Ethiopian skin color is clear."
According to Alleyne (2002), "When Christianity was adopted (and adapted) by Rome and then spread throughout the Empire, it came to be grafted onto a social religious system that had already developed a racial and ethnic hierachy and a colour symbolization which exalted whiteness and downgraded blackness."
Late antiquity
In late antiquity, some early Christian writers began connecting the metaphorical goodness and morality associated in European culture with the colour white to the physical skin colour itself, while at the same time associating the negative concepts attached to the colour black with dark skin. For example, the writer Paulinus of Nola claimed that Ethiopians had been turned black due to committing vices. Similarly Gregory of Nyssa believed that "Christ came into the world to make blacks white … Babylonians into Jerusalemites, the prostitute into a virgin, Ethiopians radiantly white." When speaking of baptising an Ethiopian, Fulgentius of Ruspe said he saw the Ethiopian as one who was "not yet whitened by the grace of Christ." According to a 7th century biography, Pope Gregory I bemoaned the presence of Anglo-Saxon child slaves in Rome who were "white of body and have blonde hair". In the 8th century, the English monk The Venerable Bede, generally associated the black skin of Ethiopians with "spiritual darkness" but at the same time rejected any idea that the colour differences between, as he termed it, "a black Ethiopian and a white Saxon" would affect their fates during the Last Judgement.
The 6th century Byzantine scholar Procopius referred to various invading barbarian tribes as being white, such as the Gothic tribes who he claimed had "white bodies and fair hair" and the Hephthalites or "White Huns" who, according to him, had "white bodies and countenances". Indian scholars also referred to the Hephthalites as Sveta Huna (White Huns). Hephthalites portrayed in the Sogdian art of the Afrasiab palace are shown as having pale or ruddy faces.
China
In pre-modern China, the Han Chinese used whiteness as a non-racial social category that included themselves while excluding many non-Chinese peoples. While whiteness was used to identify and define Chinese people, Chinese culture did not exclusively apply the term to any single ethnicity, and other ethnic groups, such as Manchus and Europeans, could be described as white. Other groups, however, such as Indonesians, and Malaysians, were referred to as "black". Chinese culture also associated light skin with having a higher social status due to light complexions signifying "freedom from manual labour".
Scholars of Ancient China also describe Indo-European-speaking peoples of north-western China, such as the Yuezhi, as having "white" or "reddish white" skin. Similarly, the Wusun tribe are said to have had green eyes and red beards.
Muslim world
During and after the Middle Ages, the peoples of the Middle East used the term white to distinguish themselves from darker-skinned "others". "White", "red", and "black" became ethnic identifiers with "black" signifying inferiority. These colour terms became fixed after the initial Arab Conquests. Whiteness in this era became a valued physical attribute, with a white complexion being associated with the social elite.
Middle Easterners noted that Europeans were "excessively white" with "pale blue" eyes. Muslim scholars of the Islamic Golden Age, such as Avicenna, described the northern tribes bordering the Muslim world as white; Avicenna writes: "The Slavs acquire whiteness / Until their Skins turn soft." The Arab explorer Ahmad ibn Fadlan during his northern travels detailed the Rus' people of the Viking Age as being "blonde and ruddy" and "big men with white bodies." The medieval Muslim sociologist Ibn Khaldun noted that those north of the Arabic-speaking world typically didn't use the term white:
The medieval Arab world used various terminology for people in reference to their skin colour with terms like al-bidan and al-abyad meaning "white people" and al-Sudan and Zanj meaning "black people". In general in the Arab world, the term "white" was used to refer to Arabs, Persians, Greeks, Turks, Slavs, and other peoples in the north. According to historian Arnold J. Toynbee, Arab rulers of the Umayyad Caliphate would sometimes refer to Persians and Turkish subjects as "the ruddy people", implying their racial inferiority. Despite this, some Islamic hagiographies say Muhammad, as well as other Abrahamic figures, had a "white or ruddy colour".
The term "white" was also used within Koranic exegesis as part of the "Curse of Ham". According to the 9th century scholar, Ibn Qutaybah, the religious writer and son of a companion of Muhammad, Wahb ibn Munabbih, related an interpretation of the story of Noah that stated Noah's son Ham had been a white man, but was later cursed by God to have his skin and the skin of his descendants turned black. As such Ham became the ancestor of all dark skinned people including Ethiopians, Nubians, Copts, and Berbers who were, according to other Islamic traditions related to the "Curse of Cannan", now also cursed to be bondsmen or slaves.
White slavery
Different labels were used to categorise slaves in Islamic society, with white slaves being referred to as mamlūk ("owned") and blacks slaves referred to as abd ("slave") and white eunuchs referred to as jarādiyya ("locusts") and black eunuchs referred to as ghurābiyya ("ravens"). According to the Arab writer Al-Jahiz, the majority of white eunuchs in medieval Basra were Slavs.
By the 10th and 11th centuries, during the era of slavery in the Abbasid Caliphate, white slaves from Spain (al-Andalus slave trade), Sicily, and the Balkans (Balkan slave trade) could be purchased in the Muslim slave markets of Damascus and Baghdad.
The Christian Arab intellectual Ibn Butlan of Baghdad wrote the first slave vade mecum, or handbook, in the 11th century, which recorded and described different ethnic and racial groups, dividing white slaves from black slaves and suggesting different tasks for each group based on their attributes.
Ibn Butlan suggested that white slaves, such as Turks and Slavs (saqaliba), should be used as soldiers while black slaves should be used as labourers, servants, and eunuchs.
Generally in the Arab world, white slaves came to be used to fill administrative and domestic positions while black slaves were used for rough labour. According to Bernard Lewis, white slaves could also conceivably become "generals, provincial governors, sovereigns and founders of dynasties", while such positions were rarely bestowed upon black slaves. Likewise, emancipated white slaves were offered more opportunities for social advancement in Arab society than emancipated black slaves. The same limitation of opportunity applies to the emancipated slave. The emancipated white slave was free from any kind of restriction; the emancipated black slave was at most times and places rarely able to rise above the lowest levels.
In medieval Southern Europe slaves came to be categorised based on colour with Christians using typical labels for Muslim slaves such as sarraceno blanco (white Saracen), sarracenno nigrium (black Saracen), and sarraceno lauram (Saracen of intermediate colour). In 13th century Barcelona the majority of Muslim slaves in slavery in Spain listed were classified as blanche (white). In 13th century Genoa slaves classified as albi (white) made up nearly half of the total recorded slave population.
Records show Provencal France would also distinguish between noir (black) and blanc (white) slaves.
In Islamic controlled Iberia (Al-Andalus) Muslims could own other Muslims as slaves during the era of slavery in al-Andalus, a practice usually banned within Islam, if the enslaved Muslims were either black or loro (of intermediate colour) but not if they were classified as white.
Generally, in medieval Iberia and Italy, people were described as white, black, or of intermediate colour.
Christendom
Medieval Christians seldom used "race" as a human category; the word emerged in 15th century Romance-language texts on animal husbandry, and writers tended instead to use words like gens and natio when classifying human groups. Medieval ideas about skin colour were complex. Dark skin – depicted in art using brown, black, blue, grey and sometimes purple hues – often signified negative moral and spiritual qualities distinct from physical appearance. Thus, the image of Saladin facing Richard I in the 14th century Luttrell Psalter depicts the Saracen with dark blue skin and a monstrous expression. Christian theologians, for whom blackness represented sin and the devil, describe the newly baptised as "whitened" by the washing away of their sins.
Female beauty
By the Late Middle Ages, the idealised, light-skinned features of high status figures in Gothic art signalled their moral purity, social rank, and political authority. The princesses of Chivalric romance and the noble ladies of courtly love literature similarly combined white skin with other positive social markers: slender proportions, graceful bearing, and expensive dress.
The ideal of feminine beauty was formalised in the 12th century by Matthew of Vendôme in the Ars Versificatoria, which includes two descriptions Helen of Troy as a model. In the first example, her forehead is white as paper, the space between her eyes white and clear (a "milky way"), her colouring white and red (like rose and snow), and her teeth like ivory. In the second portrait, her forehead is like milk, teeth like ivory, neck like snow, legs fleshy (or white).
Chaucer
According to the medievalist Candace Barrington:
Lower-class labourers ("churls") and drunkards typically have dark or ruddy faces and skinfor example, Perkyn Revelour ("brown and as berye") and the canon's yeoman (with a "leden hewe"). Dark skin is thus a consequence of "sin, sun, damnation, or putrefying flames", not a natural physical condition of certain groups of people. Chaucer's characters are all "by default, unrelentingly but invisibly white."
See also
Caucasian race
Colour psychology
Colour terminology for race
Historical race concepts
Light skin
White people
References
Further reading
Graves, Robert (1948). The White Goddess: a Historical Grammar of Poetic Myth. United Kingdom: Faber & Faber.
Human skin color
Race (human categorization)
White (human racial classification) | Pre-modern conceptions of whiteness | [
"Biology"
] | 6,062 | [
"Human skin color",
"Pigmentation"
] |
71,087,167 | https://en.wikipedia.org/wiki/HD%20193556 | HD 193556 (HR 7778) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.17, making it visible to the naked eye under ideal conditions. Parallax measurements place the object at a distance of 467 light years and it is currently receding with a heliocentric radial velocity of .
HD 193556 has a stellar classification of G8 III, indicating that it is a red giant. It has 2.65 times the mass of the Sun and is currently 490 million years old, having expanded to 11.33 times the radius of the Sun. It shines with a luminosity of from its enlarged photosphere at an effective temperature of , giving it a yellow glow. HD 193556 has an iron abundance around solar level and spins leisurely with a poorly constrained projected rotational velocity of .
References
Delphinus
G-type giants
BD+14 04263
193556
100274
7778 | HD 193556 | [
"Astronomy"
] | 199 | [
"Delphinus",
"Constellations"
] |
71,087,215 | https://en.wikipedia.org/wiki/SDSS%20J143317.78%2B101123.3 | (shortened to , more simply J1433) is a binary system composed of a white dwarf and a brown dwarf. The brown dwarf is about 57 Jupiter masses and has transitioned from a stellar object to a brown dwarf due to losing mass to the white dwarf. As of 2016, this was the only known binary of this type.
References
External links
Stellar cannibalism transforms star into brown dwarf University of Southampton
Brown dwarfs
White dwarfs
SDSS objects
Boötes | SDSS J143317.78+101123.3 | [
"Astronomy"
] | 93 | [
"Boötes",
"Constellations"
] |
71,088,819 | https://en.wikipedia.org/wiki/Keystone%20Shipping%20Company | Keystone Shipping Company of Philadelphia, Pennsylvania is a major shipping and transportation company. Keystone Shipping Company operates a fleet of ships for both dry bulk cargo and tankers. Since World War I, the Keystone Shipping Company has been active in the worldwide support of the United States Armed Forces. Keystone Shipping Company is part of the Ready Reserve Fleet program. Keystone Shipping Company was founded by Charles Kurz. Before Keystone Shipping Company, Charles Kurz was a shipping agent, commodities trader, and ship owner. Keystone Shipping Company headquarters is in Bala Cynwyd, Pennsylvania.
Keystone Shipping Company has a fleet of over 20 ships. The fleet consists of: tankers, dry bulk ships, tugboats, tank barges, and roll-on/roll-off ships. Keystone Shipping Company tanker fleet transports crude oil and other petroleum products to both coasts in the United States.
Key Lakes
Key Lakes of Duluth, Minnesota is a subsidiary Keystone Shipping Company operating on the Great Lakes with 20 ships. Key Lakes operated tankers, dry bulk ships, tugboats, tank barges, and roll-on/roll-off ships.
Alaska Tanker Company
Keystone Shipping Company entered into a partnership with in the Alaska Tanker Company. Alaska Tanker Company founded in 1999.
The other partners were: OSG America Operating Company of Tampa, Florida and BP Oil Shipping Company. Overseas Shipholding Group, Inc. (NYSE: OSG), purchased all the shares of Alaska Tanker Company on March 12, 2020, and now is a subsidiary of Overseas Shipholding Group, Inc. of Tampa. Alaska Tanker Company transport of Alaskan crude oil with four 190,000 tons tankers. Alaska Tanker Company headquarters is in Beaverton, Oregon.
Ships:
Alaska Explorer
Alaska Frontier
Alaska Legend
Alaska Navigator
Keystone Shipping Company ships
Some of Keystone Shipping Company ships:
MV Cape Kennedy (T-AKR-5083)
SS Denebola (T-AKR-289)
RS RocketShip primary route is moving rocket parts of ULA Atlas V, Delta IV and Vulcan rockets to Cape Canaveral, Fla. and Vandenberg AFB.
SS Denebola (T-AKR-289)
MV Cape Knox (T-AKR-5082)
MV Cape Kennedy (T-AKR-5083)
USNS Potomac (T-AO-181)
MV Roger Blough
Some Past ships
SS Chancellorsville T2
SS Fredericksburg (1958) 1976–2004
SS Murfreesboro T2
SS Perryville T2
SS Pueblo T2
Birch Coulie
Oakley Wood
Henry C. Wallace
New Zealand Victory
David Holmes
Alan Seeger
Little Big Horn
Fort Capot River
MV Sea Isle City
SS Bridgeton
USS Saugatuck
World War II
Keystone Shipping Company was a major tanker operator during World War II. Keystone Shipping Company operated a fleet of tankers for the War Shipping Administration. Keystone Shipping Company operated Type T2 tankers and other tankers. Keystone Shipping Company operated for the war a fleet of over 60 tankers. Each Keystone Shipping Company had a merchant crew of about 9 officers and 39 men.
Charles Kurz became the head of the War Shipping Administration (WSA) during World War II, in addition to operating ships.
Some ships operated for World War II:
SS Santee
Liberty ships:
Christopher L. Sholes
Charles A. Wickliffe
Andrew A. Humpreys
Henry L. Ellsworth
Thomas F. Cunningham
David Holmes
Oscar F. Barrett
Oscar S. Straus
T2 Tankers
Bennington
Bunker Hill
See also
World War II United States Merchant Navy
References
Keystone Shipping Company
Tanker shipping companies
Petroleum industry
Container shipping companies
Companies based in Philadelphia
Supply shipping companies
Logistics companies of the United States
Logistics industry in the United States | Keystone Shipping Company | [
"Chemistry"
] | 745 | [
"Petroleum industry",
"Petroleum",
"Chemical process engineering"
] |
71,089,176 | https://en.wikipedia.org/wiki/Crepidotus%20carpaticus | Crepidotus carpaticus, is a species of saprophytic fungus in the family Crepidotaceae with a stipeless sessile cap. The fungus was described by Albert Pilát in 1929 and is commonly found in France, the United Kingdom, and Ireland. The GBIF database indicates this species may be an orthographic variant.
Identification works
The BioImages field guide lists the following works for identification of C. carpaticus.
References
Crepidotaceae
Fungus species | Crepidotus carpaticus | [
"Biology"
] | 105 | [
"Fungi",
"Fungus species"
] |
71,089,755 | https://en.wikipedia.org/wiki/Crepidotus%20affinis | Crepidotus affinis is a species of saprophytic fungus in the family Crepidotaceae with a stipeless sessile cap. The fungus was described by Egon Horak in 2018 and has been found in New Zealand, Panama, and the Philippines.
Description
Crepidotus affinis has a similar gross morphology with C. exilis, though it has larger basidiospores and clavate cheilocystidia with a small capitate apex. The cap is fan shaped (flabelliform) with a straight margin. Colour is light brown becoming lighter towards the margin with a fine grained wrinkled (rugulose) surface.
References
Bibliography
Crepidotaceae
Fungus species | Crepidotus affinis | [
"Biology"
] | 152 | [
"Fungi",
"Fungus species"
] |
71,090,084 | https://en.wikipedia.org/wiki/Regulation%20of%20self-driving%20cars | Regulation of self-driving cars, autonomous vehicles and automated driving system is an increasingly relevant topic in the automotive industry strongly related to the success of the actual technology. Multiple countries have passed local legislation and agreed on standards for the introduction of autonomous cars.
Autonomous vehicle regulation may also apply to robotaxi and self-driving truck depending upon local legislation.
Terminology
Liability
Self-driving car liability is a developing area of law and policy that will determine who is liable when an automated car causes physical damage to persons, or breaks road rules. When automated cars shift the control of driving from humans to automated car technology the driver will need to consent to share operational responsibility which will require a legal framework. There may be a need for existing liability laws to evolve to fairly identify the parties responsible for damage and injury, and to address the potential for conflicts of interest between human occupants, system operators, insurers, and the public purse.
Introduction
Autonomous driving technologies arrived on the OECD market with an expected accelerated future deployment. Regulations aim compatibility of these automated vehicles with safety, legal responsibility and privacy public's expectations
First national regulations address various topics:
using SAE wording as a de facto standard for definitions, and terminology such as operational design domain (ODD) automated driving system (ADS), and the dynamic driving task (DDT).
Government requirements for testing automated vehicles
Safety
Data concern
Assignment of liability
Protection of people outside of automated vehicles
Several questions were raised by automated vehicles including responsibility, safety standards, software reliability, environmental performance and cybersecurity. Some in Europe consider a balanced regulatory framework is a prerequisite to the mass introduction of
these automated vehicles on the road.
One aim of the regulation of automated driving is to ensure that diverse vehicles work in their operating constraints and that drivers understand the vehicle capabilities for its safe usage.
Local approaches
In Australia, laws were designed for vehicles with human drivers, with more than 700 barriers to automated vehicles in state, territory and Commonwealth laws. Without new regulation Australia would not benefit from automated vehicles. In Australia, the goal is to codify the framework into statute by 2026 via the Automated Vehicle Safety Law (AVSL) focused in three topics: first-supply, in-service, and state/territory road transport.
China's main goals is linked to the Made in China 2035, an industrial policy framework.Level 4 AVs for consumer purchase by 2025.
In France, the Badinter law (1085) defines the driver as driving and at fault in an accident, while with automated vehicle this is questioned. For this reason a new legal framework passengers of vehicle with automated features would not be held criminally liable for accidents, but may be responsible for monetary fines under civil law, unless the driver chooses to engage automated driving when it is not adequate.
In Germany, the law for level 4 defines the requirements and specifications for approving specific automated vehicles for public road use, and the requirements for automated vehicles registration. The law also define obligations of the parties (manufacturer, owner, operator).
Japan law for level 4 defines for penalties for businesses including the revocation of permits. It also allows delivery robots up to 6 km/h to travel on sidewalks.
In the United Kingdom, the Automated and Electric Vehicles Act 2018 establish a framework related to liability between insurers, owners, and operators of automated vehicles. United Kingdom government promotes the testing of automated vehicles on public roads, without authorizing widespread introduction of automated vehicles. The Law Commissions considers that an ADS feature is self-driving only if a human is not required to perform any monitoring task until a transition demand.
International agreements
International agreements are agreement in which several states are parties.
Two international agreements addressing automated vehicles are the Conventions on Road Traffic and the amendments to 1958 UNECE agreement, where a number of European states are member.
Conventions on Road Traffic
The Geneva Convention on Road Traffic is subscribed to by over 101 countries worldwide, and requires the driver to be 18 years old.
The 1968 Vienna Convention on Road Traffic, subscribed to by 83 countries worldwide, establishes principles to govern traffic laws. One of the fundamental principles of the convention had been the concept that a driver is always fully in control and responsible for the behaviour of a vehicle in traffic.
In 2016, a reform of the convention opened the possibility of automated features in vehicles within the Vienna Convention's ratified countries.
In January 2021, a proposal of amendment to Article 1 and a new Article 34 bis to the 1968 Vienna Convention on Road Traffic was transmitted for a one-year period for acceptance.
By 14 January 2022, the amendment to the convention was accepted, entering into force on 14 July 2022.
UNECE WP.29 GRVA
In February 2018, UNECE's Inland Transport Committee (ITC) acknowledged the importance of the World Forum for Harmonization of Vehicle Regulations (WP.29) activities related to automated, autonomous and connected vehicles, and requested WP.29 to consider establishing a dedicated Working Party. At its June 2018 session WP.29 decided to convert the Working Party on Brakes and Running Gear (GRRF) into a new Working Party on Automated/Autonomous and Connected Vehicles (GRVA). The group deals with safety provisions related to the dynamics of vehicles (braking, steering), Advanced Driver Assistance Systems, Automated Driving Systems and well as cyber security provisions.
In June 2020, the WP.29 virtual meeting approved reports from GRVA about its fifth session on "automated/autonomous and connected vehicles" and sixth session on "cyber security and software updates". The new Regulation on cyber security has been allocated as Regulation 155 and the new Regulation on software updates has been allocated as Regulation 156. In this way, UN regulation on SAE Level 3 was established.
In March 2021, the following UNECE regulations were published:
Regulation 155: Cyber security and cyber security management system
Regulation 156: Software update and software update management system
Regulation 157: Automated Lane Keeping Systems (ALKS)
In June 2022, the 187th session of WP.29 was held, and several amendments on GRVA regulations were agreed to.
An amendment to UN Regulation Number 157 updated the regulations regarding Automated Lane Keeping Systems (ALKS), increasing the allowed speed limit of 60 km/h to 130 km/h, and added rules for automated lane change functions in passenger vehicles.
Legislation and regulation in Japan
Japan is a non-signatory country to the Vienna Convention. In 2019, Japan amended two laws, "Road Traffic Act" and "Road Transport Vehicle Act", and they came into effect in April 2020. In the former act, Level 3 self driving cars became allowed on public roads.
In the latter act, process to designate types for safety certification on Level 3 self driving function of
Autonomous Driving System (ADS) and the certification process for the asserted type were legally defined.
Through the amendment process, the achievements from the national project "SIP-adus" led by Cabinet Office since 2014 were fully considered and accepted.
In May 2020, "The Road Act" was also amended to include definition of automatic operation control equipment in infrastructure, and came into effect.
In July 2020, the next stage national level roadmap plan was officially issued which had considered social deployment and acceptability of Level 4.
At the end of 2020, Ministry of Land, Infrastructure, Transport and Tourism (MLIT) amended its "Safety Regulation for Road Transport Vehicle" to reflect the finalized UNECE WP.29 GRVA's regulations consistently without delay.
In April 2021, National Police Agency (NPA) published its expert committee's report of FY 2020 on summary of issues in research to realize Level 4 mobility services, including required legal amendment issues.
During the summer of 2021, Ministry of Economy, Trade and Industry (METI) prepared with MLIT to launch a project "RoAD to the L4" to cover R&D with social deployment to realize acceptable Level 4 mobility service, and updated its public information in September. As a part of this project, civil law liability problem reflecting changed roles will be clarified.
About misleading representation in marketing, Article 5 of "Act against Unjustifiable Premiums and Misleading Representations" is applied.
At the end of 2021, NPA proposed an amendment bill on "Road Traffic Act" to include approving scheme for Level 4 services.
In March 2022, the Japanese government adopted the bill to amend the act.
In April 2022, the bill was deliberated at the ordinary National Diet session and passed. Under the amended act, a license system was to be introduced for operators of transport services using unmanned Level 4 vehicles, which requires no driver in the remotely monitored vehicle within a limited area. Such vehicles are expected to be used for residents in depopulated areas.
In October 2022, NPA unveiled their plan to make the amended "Road Traffic Act" into effect in April 2023, and on 20 December 2022, Japan's cabinet decided to allow Level 4 self-driving cars to be used for transit and delivery services from 1 April 2023.
On 1 April 2023, the amended "Road Traffic Act" was enforced. The government has a target of realizing Level 4 transport services in at least 40 locations by fiscal 2025.
Legal status in the United States
In the United States, a non-signatory country to the Vienna Convention, state vehicle codes historically did not envisage—but did not necessarily prohibit—highly automated vehicles. To clarify the legal status of and regulate such vehicles, many states have enacted specific laws regarding autonomous vehicles.
In 2017, the Republican-controlled House of Representatives unanimously passed "SELF DRIVE Act" which would speed the adoption of self-driving cars and bar states from setting performance standards. However, a complementary bill in the Senate, "AV START", failed to pass after Democrats raised objections that it didn't do enough to address safety and liability concerns.
A comprehensive regulatory structure has not yet emerged at either the federal or state level in the United States.
In August 2022, members of the United States House of Representatives launched a bipartisan effort to help revive legislative efforts to boost self-driving vehicles.
Federal policies
In September 2016, the US National Economic Council and US Department of Transportation (USDOT) released the Federal Automated Vehicles Policy, which are standards that describe how automated vehicles should react if their technology fails, how to protect passenger privacy, and how riders should be protected in the event of an accident. The new federal guidelines are meant to avoid a patchwork of state laws, while avoiding being so overbearing as to stifle innovation. Since then, USDOT has released multiple updates:
Automated Driving Systems: A Vision for Safety 2.0 (12 September 2017)
Preparing for the Future of Transportation: Automated Vehicles 3.0 (4 October 2018)
Ensuring American Leadership in Automated Vehicle Technologies: Automated Vehicles 4.0 (8 January 2020)
The National Highway Traffic Safety Administration (NHTSA) released for public comment the Occupant Protection for Automated Driving System on 30 March 2020, followed by the Framework for Automated Driving System Safety on 3 December 2020. Occupant Protection is intended to modernize the Federal Motor Vehicle Safety Standards considering the removal of manual controls with automated driving systems, while the Framework document is intended to provide an objective way to define and assess automated driving system competence to ensure motor vehicle safety while also remaining flexible to accommodate the development of features to improve safety.
Historically, a vehicle without driving controls such as a steering wheel, accelerator pedal, and brake pedal would not be in compliance with the Federal Motor Vehicle Safety Standards (FMVSS), the minimum safety equipment needed to legally sell a vehicle to the public. On 10 March 2022, NHTSA updated and finalized the rule on safety requirements for the Occupant Protection to allow a vehicle without driving controls to comply with US regulations. The major update to NHTSA regulations allows companies to build and deploy autonomous vehicles without manual controls, as long as they meet other state and federal standards.
State policies
, 38 states have laws or executive orders related to autonomous vehicles.
In 2024, many more countries have dedicate law.
Nevada
In June 2011, the Nevada Legislature passed a law to authorize the use of automated cars. Nevada thus became the first jurisdiction in the world where automated vehicles might be legally operated on public roads. According to the law, the Nevada Department of Motor Vehicles is responsible for setting safety and performance standards and the agency is responsible for designating areas where automated cars may be tested. This legislation was supported by Google in an effort to legally conduct further testing of its Google driverless car. The Nevada law defines an automated vehicle to be "a motor vehicle that uses artificial intelligence, sensors and global positioning system coordinates to drive itself without the active intervention of a human operator". The law also acknowledges that the operator will not need to pay attention while the car is operating itself. Google had further lobbied for an exemption from a ban on distracted driving to permit occupants to send text messages while sitting behind the wheel, but this did not become law. Furthermore, Nevada's regulations require a person behind the wheel and one in the passenger's seat during tests.
Florida
In April 2012, Florida became the second state to allow the testing of automated cars on public roads.
California
California became the third state to allow automated car testing when Governor Jerry Brown signed SB 1298 into law in September 2012 at Google Headquarters in Mountain View.
On 19 February 2016, California Assembly Bill 2866 was introduced in California. It would allow automated vehicles to operate on public roads, including those without a driver, steering wheel, accelerator pedal, or brake pedal. The bill states that the California Department of Motor Vehicles would need to comply with these regulations by 1 July 2018 for these rules to take effect. , this bill has yet to pass the house of origin. California published discussions on the proposed federal automated vehicles policy in October 2016.
In December 2016, the California Department of Motor Vehicles ordered Uber to remove its self-driving vehicles from the road in response to two red-light violations. Uber immediately blamed the violations on human error, and has suspended the drivers.
California provides permits for testing and deploying autonomous vehicles on public roads. The first manufacturer licensed to deploy autonomous cars without a safety driver by the California DMV was Nuro, on December 23, 2020. Two more manufacturers, Cruise and Waymo, were licensed on September 30, 2021.
Massachusetts
Under the governorship of Charlie Baker in 2016, Executive Order 572 was implemented to promote the testing of autonomous vehicles on public roads in Massachusetts. The order also give directive of implementation of a Working Group on the topic and a directive for the Commonwealth's transportation authority MassDOT to begin an action process to work alongside the overall industry.
Washington, DC
In Washington, DC's district code:
In the same district code, it is considered that:
Michigan and others
In December 2013, Michigan became the fourth state to allow testing of driverless cars on public roads. In July 2014, the city of Coeur d'Alene, Idaho adopted a robotics ordinance that includes provisions to allow for self-driving cars.
Legislation in the United Kingdom
In 2013, the government of the United Kingdom permitted the testing of automated cars on public roads. Before this, all testing of robotic vehicles in the UK had been conducted on private property.
In July 2018, "The Automated and Electric Vehicles Act 2018" received royal assent.
In March 2019, the UK became a signatory country to the Vienna Convention.
In 2021, the UK worked on a bill to allow self-driving automated lane keeping systems (ALKS) up to 37 mph (or 60 km/h) after a mixed reaction of experts during the consultation launched in summer 2020. This system would be allowed to give back control to the driver when "unplanned events" such as road construction or inclement weather occurs. The Centre for Connected and Autonomous Vehicles (CCAV) has asked the Law Commission of England and Wales and the Scottish Law Commission to undertake a far-reaching review of the legal framework for "automated" vehicles, and their use as part of public transport networks and on-demand passenger services. The teams developed policy and the full analysis report was published in January 2022.
About misleading representation in marketing, the Society of Motor Manufacturers and Traders (SMMT) published guiding principles as followings:
An automated driving feature must be described sufficiently clearly so as not to mislead, including setting out the circumstances in which that feature can function.
An automated driving feature must be described sufficiently clearly so that it is distinguished from an assisted driving feature.
Where both automated driving and assisted driving features are described, they must be clearly distinguished from each other.
An assisted driving feature should not be described in a way that could convey the impression that it is an automated driving feature.
The name of an automated or assisted driving feature must not mislead by conveying that it is the other – ancillary words may be necessary to avoid confusion – for example for an assisted driving feature, by making it clear that the driver must be in control at all times.
In April 2022, UK government confirmed planned changes to "The Highway Code", responding to a public consultation. The changes will clarify drivers' responsibilities in self-driving vehicles, including when a driver must be ready to take back control.
And in August 2022, UK government unveiled a plan to roll out self-driving vehicles on UK roads.
In 2022, the British Highway Code states that:
In May 2024 the "Automated Vehicles Act 2024" received royal assent. The act was upon the joint recommendations in the 2022 joint report from the Law Commission and Scottish Law Commission.
Legislation in Europe
European Union
In November 2019, Regulation (EU) 2019/2144 of the European Parliament and of the Council on motor vehicle type approval requirements defined specific requirements relating to automated vehicles and fully automated vehicles. This law is applicable from 2022 and is based on uniform procedures and technical specifications for the systems and other items.
In April 2022, EU released a draft version of its legislation for vehicles with automated driving systems (ADS).
In July 2022, the new "Vehicle General Safety Regulation" come into effect which establishes the legal framework for the approval of automated and fully driverless vehicles (Level 3 and above) in the EU.
And the EU introduced regulations which require all new cars from 6 July 2022 to be fitted with intelligent speed assistance (ISA) (Level 2).
EU Commission delegated regulation contains specific requirements for specific vehicles with regulatory differences between:
Fully automated vehicles of categories N1, N2 and N3 without driver seat and without occupants
Fully automated vehicles of categories N1, N2, N3, M1, M2, M3 without driver seat, with occupants
Dual mode vehicles: vehicles with a driver seat designed and constructed to be driven by the driver in the “manual driving mode” and to be driven by the automated driving system (ADS) without any driver supervision in the “fully automated driving mode”
Automated vehicles deployment is addressed by several European regulations:
Regulation (EU) 2018/858
Regulation (EU) 2019/2144
Regulation (EU) 2022/2236
Regulation (EU) 2022/1426
France
France is a signatory country to the Vienna Convention on road traffic and also member of the 1958 UNECE agreement and of the European union.
In 2014, the government of France announced that testing of automated cars on public roads would be allowed in 2015. 2000 km of road would be opened through the national territory, especially in Bordeaux, in Isère, Île-de-France and Strasbourg. At the 2015 ITS World Congress, a conference dedicated to intelligent transport systems, the very first demonstration of automated vehicles on open road in France was carried out in Bordeaux in early October 2015.
In May 2018, the government published the first version of the French strategy for the development of automated road mobility to set up the legislative framework, and it brought a result as "The Mobility Orientation Law" in December 2019.
In December 2020, the government updated the strategy to make France the preferred location in Europe for the deployment of automated road mobility services.
The legislative and regulatory framework for the deployment of automated vehicles and transport systems was established through an ordinance in April 2021 and a following decree in June 2021.
The legislative and regulatory framework for the operation of automated vehicles resulting from article 31 of "the Mobility Orientation Law" is scheduled to be finalized in Q1 of 2022.
Germany
Germany is a signatory country to the Vienna Convention.
In July 2021, the "Federal Act Amending the Road Traffic Act and the Compulsory Insurance Act" came into effect.
The Act allows motor vehicles with autonomous driving capabilities, meaning vehicles that can perform driving tasks independently without a person driving, in specified operating areas on public roads. Provisions about autonomous driving in appropriate operating areas correspond to Level 4. Moreover, the new German legislation has major implications for dilemmatic situations. This includes for example the non-discrimination principle that applies to unavoidable crash situations. Moreover, the act elaborates on the technical requirements of autonomous vehicles, including a software system that can operate without permanent supervision of the technical oversight or driver, contains an accident mitigation and reduction system and can initiate a “minimal-risk state.”
In February 2022, the Federal Ministry for Digital and Transport (BMDV) submitted the "Ordinance on the Approval and Operation of Motor Vehicles with Autonomous Driving Functions in Specified Operating Areas - Autonomous Vehicles Approval and Operation Ordinance (AFGBV)" to the German Bundesrat for approval.
Switzerland
Switzerland is a signatory country to the Vienna Convention.
On 13 december 2024, Switzerland defined the ordonnance sur la conduite automatisée. According to article 53, this ordonnance should enter into force on 1 march 2025.
Legislation in North America CanadaCanada is a non-signatory country to the Vienna Convention.
At the federal level, "The Motor Vehicle Safety Act" regulates about motor vehicles which was last amended in February 2020.
In August 2021, Transport Canada released the "Guidelines for Testing Automated Driving Systems in Canada" Version 2.0.
Legislation in Asia ChinaFor historical reason, China is not a signatory country to 1949 Geneva Convention,
although it is a signatory country to 1968 Vienna Convention.
In 2018, China introduced testing regulations to regulate autonomous cars, for conditional automation, high-level automation and full automation (roughly corresponding to Level 3, Level 4 and Level 5).
The rules lay out requirements that vehicles must first be tested in non-public zones, that road tests can only be on designated streets and that a qualified person must always sit in the driver's position, ready to take over control.
In February 2020, eleven constituent departments, represented by National Development and Reform Commission (NDRC), jointly issued the "Strategy for Innovation and Development of Intelligent Vehicles" which describes about roadmap plan until 2025. This plan states about the need to revise the "Road Traffic Safety Law", and surveying and mapping law for intelligent vehicles.
In March 2020, Ministry of Industry and Information Technology (MIIT) published draft GB/T on 6-levels classification framework for driving automation which is basically corresponding to SEA levels.
And in April 2020, MIIT released about the goal of the year which is set to complete the formulation of framework for driving-assist functions and low-level autonomous driving (Level 3).
In January 2021, MIIT planned to add highways to the list of roads where provincial and city-level authorities can authorize automated cars.
In March 2021, Ministry of Public Security (MPS) published draft proposed amendments on the "Road Traffic Safety Law".
In August 2021, The Cyberspace Administration of China (CAC) and MIIT issued "the Provisions on Management of Automotive Data Security (Trial)".
In February 2022, MIIT issued the second draft of the "Administrative Measures for Data Security in the Industry and Information Technology Fields".
And in March 2022, MIIT issued "the Guidelines for the Construction of the Internet of Vehicles Cybersecurity and Data Security Standard System".
Legislation in Oceania AustraliaAustralia is a non-signatory country to the Vienna Convention.
National Transport Commission (NTC) is in charge of reforming current laws with still achieving national level consistency.
In February 2022, NTC published a policy paper to present proposals on the end-to-end regulatory framework for the commercial deployment of automated
vehicles.
Department of Infrastructure, Transport, Regional Development and Communications (DITRDC) is in charge of developing their policies and bills on first supply and in-service automated vehicle law.New ZealandNew Zealand is a non-signatory country to the Vienna Convention.
New Zealand legislation does not specifically require a driver to be present for a vehicle to be legally operated on a public road. However, most regulations and relevant international frameworks strongly imply the presence of a driver in the vehicle given that ‘automation’ was not a consideration at the time of drafting the legislation.
, Ministry of Transport is working on "Autonomous Vehicles Work Programme" with "Long-term Insights Briefing (LTIB)" which will include legislation issues.
Legislation in Middle East Israel'
Israelis a signatory country to the Vienna Convention.
, Israel Innovation Authority (OCS) is working on forming regulatory framework for trials and use of autonomous vehicles with Ministry of Transport and Road Safety (MOT) and Ministry of Justice.
In March 2022, the Knesset passed legislation that will allow companies to pilot autonomous shared transportation with passengers in the vehicle but without a safety driver on Israeli roads. The legislation allows companies and vehicle operators to obtain special licenses from MOT and to conduct trials with autonomous cars including for the purpose of transporting paying passengers and where an independent driving system replaces the driver.
References
Regulation of robots | Regulation of self-driving cars | [
"Engineering"
] | 5,233 | [
"Automotive engineering",
"Self-driving cars"
] |
71,090,532 | https://en.wikipedia.org/wiki/Crepidotus%20albescens | Crepidotus albescens is a species of saprophytic fungus in the family Crepidotaceae with a stipeless sessile cap.
Description
Crepidotus albescens is distinguished by its remarkably elongate cheilocystidia which is subcylindric to more or less narrowly flask shaped (lageniform). The pileipellis is made up of filamentous, undifferentiated terminal elements.
References
Crepidotaceae
Fungi described in 1984
Fungus species | Crepidotus albescens | [
"Biology"
] | 110 | [
"Fungi",
"Fungus species"
] |
71,091,028 | https://en.wikipedia.org/wiki/Crepidotus%20albolanatus | Crepidotus albolanatus, is a species of saprophytic fungus in the family Crepidotaceae with a stipeless sessile finely felted cap. Colour is pure white, cap diameter 10–35 mm and has been found in New Zealand on the debris of the nikau palm (Rhopalostylis sapida).
References
Crepidotaceae
Fungi of New Zealand
Fungus species | Crepidotus albolanatus | [
"Biology"
] | 89 | [
"Fungi",
"Fungus species"
] |
69,553,733 | https://en.wikipedia.org/wiki/Jacquelien%20Scherpen | Jacquelien Maria Aleida Scherpen is a Dutch applied mathematician specializing in nonlinear control theory. She is a professor in the faculty of science and engineering at the University of Groningen, director of the Groningen Engineering Center, and former scientific director of the Engineering and Technology Institute Groningen (ENTEG). She has been rector magnificus of the university since September 2023.
Education and career
Scherpen studied applied mathematics at the University of Twente, earning a master's degree in 1990 and completing her Ph.D. in 1994. Her doctoral dissertation, Balancing for Nonlinear Systems, was jointly promoted by Huibert Kwakernaak and Arjan van der Schaft.
She was affiliated with the Delft University of Technology from 1994 until 2006, when she moved to her present position at the University of Groningen. She was scientific director of ENTEG from 2013 to 2019, and has directed the Groningen Engineering Center since 2016.
On 1 September 2023 she became rector magnificus of the university, succeeding Cisca Wijmenga.
Recognition
Scherpen was named an IEEE Fellow in 2021 "for contributions to nonlinear model reduction and passivity-based control". She is also a knight of the Order of the Netherlands Lion. In 2022, she was elected Chair of the Society for Industrial and Applied Mathematics Activity Group on Control and Systems Theory (SIAM SIAG/CST).
References
External links
Home page
Year of birth missing (living people)
Living people
Dutch mathematicians
Dutch women mathematicians
Control theorists
University of Twente alumni
Academic staff of the Delft University of Technology
Academic staff of the University of Groningen
Knights of the Order of the Netherlands Lion
Fellows of the IEEE
Rectors of universities in the Netherlands | Jacquelien Scherpen | [
"Engineering"
] | 352 | [
"Control engineering",
"Control theorists"
] |
69,553,757 | https://en.wikipedia.org/wiki/GJ%201002 | GJ 1002 (or Gliese 1002) is a nearby red dwarf star, located away from the Solar System in the constellation of Cetus. The star has 12% the mass and 14% the radius of the Sun, and a temperature of . It hosts a system of two known exoplanets.
Planetary system
Two planetary companions to GJ 1002 were discovered in 2022 via radial velocity. Both have minimum masses close to that of Earth and orbit within the habitable zone of their star. While these planets do not transit their host star, it may be possible to determine the presence and composition of atmospheres with future instruments such as the ANDES spectrograph for the Extremely Large Telescope.
See also
Proxima Centauri b
Ross 128
GJ 1061
Teegarden's Star
References
Cetus
M-type main-sequence stars
Planetary systems with two confirmed planets
1002
J00064325-0732147
Suspected variables | GJ 1002 | [
"Astronomy"
] | 197 | [
"Cetus",
"Constellations"
] |
69,554,048 | https://en.wikipedia.org/wiki/HR%204098 | HR 4098, also known as HD 90508, is a binary star system in the northern constellation of Ursa Major at a distance of 75 light years. This object is barely visible to the naked eye as a dim, yellow star with an apparent visual magnitude of 6.45. It is approaching the Earth with a heliocentric radial velocity of 7.2 km/s.
The star system is a visual binary with a 3.466″ projected separation, identified as such in 1994–1997. The orbit of the binary is wide and highly uncertain due to the long period and high inclination.
The larger star, HD 90508A, is a very old main-sequence star approaching a turn-off from the main sequence. Very little dust remains in the stellar system, therefore the starlight of HR 4098 is one of the standards for non-polarized emission, polarization being below 0.2% in all bands. Unlike the majority of G-class stars, HD 90508A has a direct correlation between brightness and stellar activity. This behavior is shared with HD 88986 and the Sun.
Very little is known about the companion, which could be a K-class or M-class dwarf star.
References
G-type main-sequence stars
Binary stars
Solar analogs
Ursa Major
BD+49 1961
090508
051248
4098
J10280388+4847067
0392 | HR 4098 | [
"Astronomy"
] | 300 | [
"Ursa Major",
"Constellations"
] |
69,554,597 | https://en.wikipedia.org/wiki/Biodiversity%20of%20Portugal | Portugal is located on the Mediterranean Basin, the third most diverse hotspot of flora in the world. Due to its geographical and climatic context - between the Atlantic and Mediterranean - Portugal has a high level of biodiversity on land and at sea. It is home to six terrestrial ecoregions: Azores temperate mixed forests, Cantabrian mixed forests, Madeira evergreen forests, Iberian sclerophyllous and semi-deciduous forests, Northwest Iberian montane forests, and Southwest Iberian Mediterranean sclerophyllous and mixed forests. Over 22% of its land area is included in the Natura 2000 network, including 62 special conservation areas and 88 types of protected landscape natural habitats.
Eucalyptus (non-native, commercial plantations), cork oak and maritime pine together make up 71% of the total forested area of continental Portugal, followed by the holm oak, the stone pine, the other oak trees (Q. robur, Q. faginea and Q. pyrenaica) and the sweet chestnut, respectively. In Madeira, laurisilva (recognized as a World Heritage Site) dominates the landscape, especially on the northern slope. The predominant species in this forest include Laurus novocanariensis, Apollonias barbujana, Ocotea foetens and Persea indica. Before human occupation the Azores were also rich in dense laurisilva forests, today these native forests are undermined by the introduced Pittosporum undulatum and Cryptomeria japonica. There have been several projects aimed to recover the Laurisilva present in the Azores. Remnants of these laurisilva forests are also present in continental Portugal with its few living testimonies Laurus nobilis, Prunus lusitanica, Arbutus unedo, Myrica faya and Rhododendron ponticum.
These geographical and climatic conditions facilitate the introduction of exotic species that later turn to be invasive and destructive to the native habitats. Around 20% of the total number of extant species in continental Portugal are exotic. In Madeira, around 36% and in the Azores, around 70% species are exotic. Due to this, Portugal was placed 168th globally out of 172 countries on the Forest Landscape Integrity Index in 2019.
Portugal is the second country in Europe with the highest number of threatened animal and plant species (488 as of 2020).
Portugal as a whole is an important stopover for migratory bird species: the southern marshes of the eastern Algarve (Ria Formosa, Castro Marim) and the Lisbon Region (Tagus Estuary, Sado Estuary) hosting various aquatic bird species, the Bonelli's eagle and Egyptian vulture on the northern valleys of the Douro International, the black stork and griffon vulture on the Tagus International, the seabird sanctuaries of the Savage Islands and Berlengas and the highlands of Madeira and São Miguel all represent the great diversity of wild avian species (around 450 in continental Portugal), not only migratory but also endemic (e.g. trocaz pigeon, Azores bullfinch) or exotic (crested myna, pin-tailed whydah).
The large mammalian species of Portugal (the fallow deer, red deer, roe deer, Iberian ibex, wild boar, red fox, Iberian wolf and Iberian lynx) were once widespread throughout the country, but intense hunting, habitat degradation and growing pressure from agriculture and livestock reduced population numbers on a large scale in the 19th and early 20th century, others, such as the Portuguese ibex were even led to extinction. Today, these animals are re-expanding their native range. Smaller mammals include the red squirrel, European badger, Eurasian otter, Egyptian mongoose, Granada hare, European rabbit, common genet, European wildcat, among others.
Due to their isolated location, the volcanic islands of the Azores, Madeira and Salvages, part of Macaronesia, have many endemic species that have evolved independently from their European, African and occasionally American relatives.
The Portuguese west coast is part of the four major Eastern Boundary Upwelling Systems of the ocean. This seasonal upwelling system typically seen during the summer months brings cooler, nutrient rich water up to the sea surface promoting phytoplankton growth, zooplankton development and the subsequent rich diversity in pelagic fish and other marine invertebrates.
This, adding to its large EEZ makes Portugal one of the largest per capita fish-consumers in the world. Sardines (Sardina pilchardus) and horse mackerel (Trachurus trachurus) are collected in the thousands every year. while blue whiting, monkfish, Atlantic cod, cephalopods, skates or any other form of seafood are traditionally fished in the local coastal villages. This upwelling also allows Portugal to have kelp forests which are otherwise very uncommon or non-existent on the Mediterranean.
73% of the freshwater fish occurring in the Iberian Peninsula are endemic, the largest out of any region in Europe. Many of these endemic species are concentrated in bodies of water of the central western region (one exclusively endemic), these and other bodies of water throughout the Peninsula are mostly temporary and prone to drought every year, placing most of these species under Threatened status.
Around 24 to 28 species of cetacean roam through the Azores, making it one of four places in the world where most species of this infraorder occur. Starting in the mid-19th century and ceasing in 1984, whaling (especially of sperm whale) heavily exploited this diversity. Beginning in the early 90s, whale watching quickly grew to popularity and is now one of the main economic activities in the Portuguese archipelago.
Some protected areas in Portugal other than the ones previously mentioned include: the Serras de Aire e Candeeiros with its limestone formations, paleontological history and great diversity in bats and orchids, the Southwest Alentejo and Vicentine Coast Natural Park with its well preserved, wild coastline. the Montesinho Natural Park which hosts some of the only populations of Iberian wolf and recent sightings of Iberian brown bear, which had been considered extinct in the country; among other species.
References
Biodiversity
Biota of Portugal
Environment of Portugal
Geography of Portugal | Biodiversity of Portugal | [
"Biology"
] | 1,273 | [
"Biota by country",
"Biodiversity",
"Biota of Portugal"
] |
69,554,665 | https://en.wikipedia.org/wiki/ADB-BUTINACA | ADB-BUTINACA (also known as ADMB-BINACA using EMCDDA naming standards) is a synthetic cannabinoid compound which has been sold as a designer drug. It is a potent CB1 agonist, with a binding affinity of 0.29nM for CB1 and 0.91nM for CB2, and an EC50 of 6.36 nM for CB1.
See also
ADB-BINACA
ADB-PINACA
ADB-HEXINACA
ADB-5'F-BUTINACA
ADB-5'Br-BUTINACA
MDMB-BINACA
References
Cannabinoids
Designer drugs
Indazolecarboxamides
Tert-butyl compounds
Amides | ADB-BUTINACA | [
"Chemistry"
] | 151 | [
"Amides",
"Functional groups"
] |
69,555,414 | https://en.wikipedia.org/wiki/Papain-like%20protease | Papain-like proteases (or papain-like (cysteine) peptidases; abbreviated PLP or PLCP) are a large protein family of cysteine protease enzymes that share structural and enzymatic properties with the group's namesake member, papain. They are found in all domains of life. In animals, the group is often known as cysteine cathepsins or, in older literature, lysosomal peptidases. In the MEROPS protease enzyme classification system, papain-like proteases form Clan CA. Papain-like proteases share a common catalytic dyad active site featuring a cysteine amino acid residue that acts as a nucleophile.
The human genome encodes eleven cysteine cathepsins which have a broad range of physiological functions. In some parasites papain-like proteases have roles in host invasion, such as cruzipain from Trypanosoma cruzi. In plants, they are involved in host defense and in development. Studies of papain-like proteases from prokaryotes have lagged their eukaryotic counterparts. In cellular organisms they are synthesized as preproenzymes that are not enzymatically active until mature, and their activities are tightly regulated, often by the presence of endogenous protease inhibitors such as cystatins. In many RNA viruses, including significant human pathogens such as the coronaviruses SARS-CoV and SARS-CoV-2, papain-like protease protein domains often have roles in processing of polyproteins into mature viral nonstructural proteins. Many papain-like proteases are considered potential drug targets.
Classification
The MEROPS system of protease enzyme classification defines clan CA as containing the papain-like proteases. They are thought to have a shared evolutionary origin. As of 2021, the clan contained 45 families.
Structure
The structure of papain was among the earliest protein structures experimentally determined by X-ray crystallography. Many papain-like protease enzymes function as monomers, though a few, such as cathepsin C (Dipeptidyl-peptidase I), are homotetramers. The mature monomer structure is characteristically divided into two lobes or subdomains, known as the L-domain (N-terminal) and the R-domain (C-terminal), where the active site is located between them. The L-domain is primarily helical while the R-domain contains beta-sheets in a beta-barrel-like shape, surrounded by a helix. The enzyme substrate interacts with both domains in an extended conformation.
Papain-like proteases are often synthesized as preproenzymes, or enzymatically inactive precursors. A signal peptide at the N-terminus, which serves as a subcellular localization signal, is cleaved by signal peptidase to form a zymogen. Post-translational modification in the form of N-linked glycosylation also occurs in parallel. The zymogen is still inactive due to the presence of a propeptide which functions as an inhibitor blocking access to the active site. The propeptide is removed by proteolysis to form the mature enzyme.
Catalytic mechanism
Papain-like proteases have a catalytic dyad consisting of a cysteine and a histidine residue, which form an ion pair through their charged thiolate and imidazolium side chains. The negatively charged cysteine thiolate functions as a nucleophile. Additional neighboring residues—aspartate, asparagine, or glutamine—position the catalytic residues; in papain, the required catalytic residues cysteine, histidine, and aspartate are sometimes called the catalytic triad (similar to serine proteases). Papain-like proteases are usually endopeptidases, but some members of the group are also, or even exclusively, exopeptidases. Some viral papain-like proteases, including those of coronaviruses, can also cleave isopeptide bonds and can function as deubiquitinases.
Function
Eukaryotes
Mammals
In animals, especially in mammalian biology, members of the papain-like protease family are usually referred to as cysteine cathepsins—that is, the cysteine protease members of the group of proteases known as cathepsins (which includes cysteine, serine, and aspartic proteases). In humans, there are 11 cysteine cathepsins: B, C, F, H, K, L, O, S, V, X, and W. Most cathepsins are expressed throughout the body, but some have narrower tissue distribution.
Although historically known as lysosomal proteases and studied mainly for their role in protein catabolism, cysteine cathepsins have since been identified playing major roles in a number of physiological processes and disease states. As part of normal physiological processes, they are involved in key steps of antigen presentation as part of the adaptive immune system, remodeling of the extracellular matrix, differentiation of keratinocytes, and processing of peptide hormones. Cysteine cathepsins have been associated with cancer and tumor progression, cardiovascular disease, autoimmune disease, and other human health conditions. Cathepsin K has a role in bone resorption and has been studied as a drug target for osteoporosis.
Parasites
A number of parasites, including helminths (parasitic worms), use papain-like proteases as mechanisms for invasion of their hosts. Examples include Toxoplasma gondii and Giardia lamblia. In many flatworms, there are very high levels of expression of cysteine cathepsins; in the liver fluke Fasciola hepatica, gene duplications have produced over 20 paralogs of a cathepsin L-like enzyme. Cysteine cathepsins are also part of the normal life cycle of the unicellular parasite Leishmania, where they function as virulence factors. The enzyme and potential drug target cruzipain is important for the life cycle of the parasite Trypanosoma cruzi, which causes Chagas' disease.
Plants
Members of the papain-like protease family play a number of important roles in plant development, including seed germination, leaf senescence, and responding to abiotic stress. Papain-like proteases are involved in regulation of programmed cell death in plants, for example in tapetum during development of pollen. They are also important in plant immunity providing defense against pests and pathogens. The relationship between plant papain-like proteases and pathogen responses—such as cystatin inhibitors—have been described as an evolutionary arms race.
Some PLP family members in plants have culinary and commercial applications. The family's namesake member, papain, is a protease derived from papaya, used as a meat tenderizer. Similar but less widely used plant products include bromelain from pineapple and ficin from figs.
Prokaryotes
Although papain-like proteases are found in all domains of life, they have been less well-studied in prokaryotes than in eukaryotes. Only a few prokaryotic PLP enzymes have been characterized by X-ray crystallography or enzymatic studies, mostly from pathogenic bacteria, including streptopain from Streptococcus pyogenes; xylellain, from the plant pathogen Xylella fastidiosa; Cwp84 from Clostridioides difficile; and Lpg2622 from Legionella pneumophila.
Viruses
The papain-like protease family includes a number of protein domains that are found in large polyproteins expressed by RNA viruses. Among the best studied viral PLPs are nidoviral papain-like protease domains from nidoviruses, particularly those from coronaviruses. These PLPs are responsible for several cleavage events that process a large polyprotein into viral nonstructural proteins, although they perform fewer cleavages than the 3C-like protease (also known as the main protease). Coronavirus PLPs are multifunctional enzymes that can also act as deubiquitinases (cleaving the isopeptide bond to ubiquitin) and "deISGylating enzymes" with analogous activity against the ubiquitin-like protein ISG15. In human pathogens including SARS-CoV, MERS-CoV, and SARS-CoV-2, the PLP domain is essential for viral replication and is therefore considered a drug target for the development of antiviral drugs. One such experimental antiviral medication, Jun12682, is being studied as a potential treatment for COVID-19, and it is believed to work by inhibiting SARS-CoV-2 papain-like protease (PLpro). The surface zone of SARS-CoV-2 PLpro participating in binding of cellular proteins can also be targeted by bioactive molecules, such as glycyrrhizinic acid, thus potentially preventing protein-protein complexation.
References
Proteases
Protein superfamilies | Papain-like protease | [
"Biology"
] | 2,007 | [
"Protein superfamilies",
"Protein classification"
] |
69,555,703 | https://en.wikipedia.org/wiki/Serruria%20stellata | Serruria stellata, the star spiderhead, is a flower-bearing shrub that belongs to the genus Serruria and forms part of the fynbos. The plant is native to the Western Cape, South Africa.
Description
The shrub is small with creeping stems and grows only tall and flowers from September to November. Fire destroys the plant but the seeds survive. Two months after flowering, the fruit falls off and ants disperse the seeds. They store the seeds in their nests. The plant is unisexual and pollinated by insects.
In Afrikaans, it is known as .
Distribution and habitat
The plant occurs from the Stettyns Mountains to the western Riviersonderend Mountains. It grows in sandstone sand at elevations of .
References
Vulnerable plants
stellata
Shrubs
Vulnerable species
Endemic flora of the Cape Provinces
Fynbos | Serruria stellata | [
"Biology"
] | 168 | [
"Vulnerable species",
"Biota by conservation status"
] |
69,557,760 | https://en.wikipedia.org/wiki/Flight-time%20equivalent%20dose | Flight-time equivalent dose (FED) is an informal unit of measurement of ionizing radiation exposure. Expressed in units of flight-time (i.e., flight-seconds, flight-minutes, flight-hours), one unit of flight-time is approximately equivalent to the radiological dose received during the same unit of time spent in an airliner at cruising altitude. FED is intended as a general educational unit to enable a better understanding of radiological dose by converting dose typically presented in sieverts into units of time. FED is only meant as an educational exercise and is not a formally adopted dose measurement.
History
The flight-time equivalent dose concept is the creation of Ulf Stahmer, a Canadian professional engineer working in the field of radioactive materials transport. It was first presented in the poster session at the 18th International Symposium of the Packaging and Transport of Radioactive Materials (PATRAM) held in Kobe, Hyogo, Japan where the poster received an Aoki Award for distinguished poster presentation. In 2018, an article on FED appeared in the peer-reviewed journal The Physics Teacher.
Usage
Flight-time equivalent dose is an informal measurement, so any equivalences are necessarily approximate. It has been found useful to provide context between radiological doses received from various every-day activities and medical procedures.
Dose calculation
FED corresponds to the time spent in an airliner flying at altitude required to receive a corresponding radiological dose. FED is calculated by taking a known dose (typically in millisieverts) and dividing it by the average dose rate (typically in millisieverts per hour) at an altitude of 10,000 m, a typical cruising altitude for a commercial airliner.
While radiological dose at cruising altitudes varies with latitude, for FED calculations, the radiological dose rate at an altitude of 10,000 m has been standardized to be 0.004 mSv/h, about 15 times greater than the average dose rate at the Earth's surface. Using this technique, the FED received from a 0.01 mSv panoramic dental x-ray is approximately equivalent to 2.5 flight-hours; the FED received from eating one banana is approximately equal to 1.5 flight-minutes; and the FED received each year from naturally occurring background radiation (2.4 mSv/year) is approximately equivalent to 600 flight-hours.
Radiological exposures and limits
For comparison, a list of activities (including common medical procedures) and their estimated radiological exposures are tabulated below. Regulatory occupational dose limits for the public and radiation workers are also included. Items on this list are represented pictorially in the accompanying illustrations.
See also
Background radiation
Background radiation equivalent time
Banana equivalent dose
List of unusual units of measurement
References
Radioactivity quantities
Background radiation
Equivalent units | Flight-time equivalent dose | [
"Physics",
"Chemistry",
"Mathematics"
] | 562 | [
"Equivalent quantities",
"Units of measurement",
"Physical quantities",
"Quantity",
"Equivalent units",
"Radioactivity quantities",
"Radioactivity"
] |
69,557,765 | https://en.wikipedia.org/wiki/Complex%20hyperbolic%20space | In mathematics, hyperbolic complex space is a Hermitian manifold which is the equivalent of the real hyperbolic space in the context of complex manifolds. The complex hyperbolic space is a Kähler manifold, and it is characterised by being the only simply connected Kähler manifold whose holomorphic sectional curvature is constant equal to -1. Its underlying Riemannian manifold has non-constant negative curvature, pinched between -1 and -1/4 (or -4 and -1, according to the choice of a normalization of the metric): in particular, it is a CAT(-1/4) space.
Complex hyperbolic spaces are also the symmetric spaces associated with the Lie groups . They constitute one of the three families of rank one symmetric spaces of noncompact type, together with real and quaternionic hyperbolic spaces, classification to which must be added one exceptional space, the Cayley plane.
Construction of the complex hyperbolic space
Projective model
Let be a pseudo-Hermitian form of signature in the complex vector space . The projective model of the complex hyperbolic space is the projectivized space of all negative vectors for this form:
As an open set of the complex projective space, this space is endowed with the structure of a complex manifold. It is biholomorphic to the unit ball of , as one can see by noting that a negative vector must have non zero first coordinate, and therefore has a unique representative with first coordinate equal to 1 in the projective space. The condition when is equivalent to . The map sending the point of the unit ball of to the point of the projective space thus defines the required biholomorphism.
This model is the equivalent of the Poincaré disk model. Unlike the real hyperbolic space, the complex projective space cannot be defined as a sheet of the hyperboloid , because the projection of this hyperboloid onto the projective model has connected fiber (the fiber being in the real case).
A Hermitian metric is defined on in the following way: if belongs to the cone , then the restriction of to the orthogonal space defines a definite positive hermitian product on this space, and because the tangent space of at the point can be naturally identified with , this defines a hermitian inner product on . As can be seen by computation, this inner product does not depend on the choice of the representative . In order to have holomorphic sectional curvature equal to -1 and not -4, one needs to renormalize this metric by a factor of . This metric is a Kähler metric.
Siegel model
The Siegel model of complex hyperbolic space is the subset of such that
It is biholomorphic to the unit ball in via the Cayley transform
Boundary at infinity
In the projective model, the complex hyperbolic space identifies with the complex unit ball of dimension , and its boundary can be defined as the boundary of the ball, which is diffeomorphic to the sphere of real dimension . This is equivalent to defining :
As a CAT(0) space, the complex hyperbolic space also has a boundary at infinity . This boundary coincides with the boundary just defined.
The boundary of the complex hyperbolic space naturally carries a CR structure. This structure is also the standard contact structure on the (odd dimensional) sphere.
Group of holomorphic isometries and symmetric space
The group of holomorphic isometries of the complex hyperbolic space is the Lie group . This group acts transitively on the complex hyperbolic space, and the stabilizer of a point is isomorphic to the unitary group . The complex hyperbolic space is thus homeomorphic to the homogeneous space . The stabilizer is the maximal compact subgroup of .
As a consequence, the complex hyperbolic space is the Riemannian symmetric space , where is the pseudo-unitary group.
The group of holomorphic isometries of the complex hyperbolic space also acts on the boundary of this space, and acts thus by homeomorphisms on the closed disk . By Brouwer's fixed point theorem, any holomorphic isometry of the complex hyperbolic space must fix at least one point in . There is a classification of isometries into three types:
An isometry is said to be elliptic if it fixes a point in the complex hyperbolic space.
An isometry is said to be parabolic if it does not fix a point in the complex hyperbolic space and fixes a unique point in the boundary.
An isometry is said to be hyperbolic (or loxodromic) if it does not fix a point in the complex hyperbolic space and fixes exactly two points in the boundary.
The Iwasawa decomposition of is the decomposition , where is the unitary group, is the additive group of real numbers and is the Heisenberg group of real dimension . Such a decomposition depends on the choice of :
A point in the boundary of the complex hyperbolic space ( is then the group of unipotent parabolic elements of fixing )
An oriented geodesic line going to at infinity ( is then the group of hyperbolic elements of acting as a translation along this geodesic and with no rotational part around it)
The choice of an origin for , i.e. a unit speed parametrization whose image is ( is then the group of elliptic elements of fixing )
For any such decomposition of , the action of the subgroup is free and transitive, hence induces a diffeomorphism . This diffeomorphism can be seen as a generalization of the Siegel model.
Curvature
The group of holomorphic isometries acts transitively on the tangent complex lines of the hyperbolic complex space. This is why this space has constant holomorphic sectional curvature, that can be computed to be equal to -4 (with the above normalization of the metric). This property characterizes the hyperbolic complex space : up to isometric biholomorphism, there is only one simply connected complete Kähler manifold of given constant holomorphic sectional curvature.
Furthermore, when a Hermitian manifold has constant holomorphic sectional curvature equal to , the sectional curvature of every real tangent plane is completely determined by the formula :
where is the angle between and , ie the infimum of the angles between a vector in and a vector in . This angle equals 0 if and only if is a complex line, and equals if and only if is totally real. Thus the sectional curvature of the complex hyperbolic space varies from -4 (for complex lines) to -1 (for totally real planes).
In complex dimension 1, every real plane in the tangent space is a complex line: thus the hyperbolic complex space of dimension 1 has constant curvature equal to -1, and by the uniformization theorem, it is isometric to the real hyperbolic plane. Hyperbolic complex spaces can thus be seen as another high-dimensional generalization of the hyperbolic plane, less standard than the real hyperbolic spaces. A third possible generalization is the homogeneous space , which for again coincides with the hyperbolic plane, but becomes a symmetric space of rank greater than 1 when .
Totally geodesic subspaces
Every totally geodesic submanifold of the complex hyperbolic space of dimension n is one of the following :
a copy of a complex hyperbolic space of smaller dimension
a copy of a real hyperbolic space of real dimension smaller than
In particular, there is no codimension 1 totally geodesic subspace of the complex hyperbolic space.
Link with other metrics on the ball
On the unit ball, the complex hyperbolic metric coincides, up to some scalar renormalization, with the Bergman metric. This implies that every biholomorphism of the ball is actually an isometry of the complex hyperbolic metric.
The complex hyperbolic metric also coincides with the Kobayashi metric.
Up to renormalization, the complex hyperbolic metric is Kähler-Einstein, which means that its Ricci curvature is a multiple of the metric.
See also
Hyperbolic space
Quaternionic hyperbolic space
References
Lie groups
Homogeneous spaces
Complex manifolds
Hyperbolic geometry | Complex hyperbolic space | [
"Physics",
"Mathematics"
] | 1,663 | [
"Lie groups",
"Mathematical structures",
"Group actions",
"Homogeneous spaces",
"Space (mathematics)",
"Topological spaces",
"Algebraic structures",
"Geometry",
"Symmetry"
] |
69,559,313 | https://en.wikipedia.org/wiki/Donald%20Kreider | Donald Lester Kreider (December 5, 1931 – December 7, 2006) was an American mathematician and educator who served as president of the Mathematical Association of America (1993–1994).
Early life
Kreider was born on December 5, 1931, in Lancaster, Pennsylvania. He attended high school in Lititz, Pennsylvania, and college at Lebanon Valley College, where he received a bachelor's degree in 1953. In 1959, he received a PhD in mathematics from the Massachusetts Institute of Technology for a thesis in recursive function theory supervised by Hartley Rogers.
Career
Kreider spent a postdoctoral year at MIT before joining the Department of Mathematics at Dartmouth College in 1960. At both MIT and Dartmouth, Kreider was known for excellent teaching. His advisor Hartley Rogers at MIT commented that "he had a graduate student [who] was an extraordinary teacher [and] won the Goodwin Medal for teaching at MIT". John Kemeny at Dartmouth remarked that it was difficult to find faculty who could teach well at both the undergraduate and graduate levels, but that "occasionally you are lucky—Don
Kreider is an example. Don is spectacular at anything he teaches."
Initially, Kreider continued research and writing in recursive function theory, working with Robert W. Ritchie. But he increasingly turned his attention to mathematical pedagogy, writing textbooks in recursive function theory, differential equations, and linear analysis with colleagues in the Department of Mathematics.
Starting in 1960, Kreider became active in the Committee on the Undergraduate Program in Mathematics (CUPM) at the Mathematical Association of America (MAA), where he later led the Subpanel on Calculus and received one of the first grants in the Calculus Initiative launched by the National Science Foundation in 1989.
Kreider had a long-standing interest in the use of computation in teaching calculus. Working with John Kemeny and Thomas E. Kurtz, he developed programs that provided
automatic feedback to students about four programs in Dartmouth Basic that they were assigned to write in freshman mathematics courses taken by 80% of all Dartmouth students. Later he was lead author of a book supporting the use of the HP-48G/GX calculator and co-author with his colleague Dwight Lahr of an interactive set of teaching modules.
Also in the 1960s, Kreider chaired the school board in Norwich, Vermont and was instrumental in forming the Dresden School District, the first inter-state school district in the United States, between Norwich and Hanover, New Hampshire. He spent three summers with the Entebbe Project in Africa, where he worked with local teachers on a high school mathematics curriculum, textbooks, and teacher training materials.
In the 1970s, Kreider chaired the College Board Calculus Development Committee and was a member of its Mathematical Science Advisory Committee, where he promoted the development of an Advanced Placement course in computer science.
At Dartmouth, Kreider had a particularly close relationship with John Kemeny. In 1967, he succeeded Kemeny as Chairman of the Department of Mathematics, which Kemeny had chaired since 1954. From 1972 to 1975, he was Vice President and Dean for Student Affairs. John Kemeny, who had become President of Dartmouth in 1970, sought help from Kreider and Ruth Adams, a former President of Wellesley College, in managing the expansion of Dartmouth College as it began admitting women as well as significant numbers of Native American and minority students. A key factor in the expansion was the Dartmouth Plan, under which Dartmouth went to year-round operation to accommodate a larger student body without having to admit fewer men. And a key factor in the Dartmouth Plan was Project FIND (Forecasting Institutional Needs at Dartmouth), for which Kreider chaired the coordinating committee, that created an information management information system on the Dartmouth Time-Sharing System and integrated it with all planning aspects of the College.
After returning to the Dartmouth Mathematics Department in 1975, Kreider served another term as its chairman and became increasing active in the Mathematical Association of America. He served as its treasurer from 1986 to 1992 when, according to his successor Gerald J. Porter, "the MAA made remarkable strides toward putting both its financial and physical houses in order." He also served as the MAA president-elect (1992), as its president (1993–1994), and on its Board of Governors (1995–1999).
Kreider retired from Dartmouth in 1997. He died on December 7, 2006, at the age of 75.
Selected publications
Donald L. Kreider, Robert G. Kuller, Donald R. Ostberg, and Fred W. Perkins, An Introduction to Linear Analysis, Addison-Wesley Series in Mathematics, 1966.
Donald Kreider, Dwight Lahr, and Susan Diesel, Principles of Calculus Modeling, An Interactive Approach, Department of Mathematics, Dartmouth College
D. L. Kreider and R. W. Ritchie, "Predictably computable functionals and definition by recursion," Zeitschrift fur mathematische Logik und Grundlagen der Mathematik 10:5, 1964, pages 65–80
Donald L. Kreider & Hartley Rogers, Jr., "Constructive versions of ordinal number classes", Transactions of the American Mathematical Society 100:2, August 1961), pages 325 369
Donald L. Kreider, Robert G. Kuller, and Donald R. Ostberg, Elementary Differential Equations, Addison-Wesley Publishing Company, 1968.
Donald R. Latorre, Donald L. Kreider, T. G. Proctor, HP-48G/GX Investigations in Mathematics, Charles River Media, 1996.
References
External links
Oral history interview with Donald Kreider, Rauner Special Collections Library, Dartmouth College
1931 births
2006 deaths
Presidents of the Mathematical Association of America
20th-century American mathematicians
Advanced Placement
Calculus
Mathematicians from Pennsylvania
Dartmouth College faculty
Dresden School District
People from Lancaster, Pennsylvania
Massachusetts Institute of Technology alumni
Lebanon Valley College alumni | Donald Kreider | [
"Mathematics"
] | 1,217 | [
"Calculus"
] |
69,559,697 | https://en.wikipedia.org/wiki/Bareiss%20Pr%C3%BCfger%C3%A4tebau%20GmbH | Bareiss (full name: Bareiss Prüfgerätebau GmbH) is a German materials testing company founded in 1954 by Heinrich Bareiss. The company specialises in material testing equipment and is headquartered in Oberdischingen, Germany.
Testing instruments
Bareiss manufactures durometers, automatic hardness testers, temperature-controlled hardness testers, density testers, ball rebound testers, rheology equipment such as rubber process analyzers, and an automated optical inspections system. Most of the product components are manufactured in-house.
Bareiss is also the first DKD calibration laboratory (today: DAkkS laboratory) in Europe, according to DIN EN ISO 17025 for the calibrations of the measurement category of hardness, according to Shore DIN ISO 48-4 and DIN ISO 48-2.
History
Bareiss was founded in 1954 by Heinrich Bareiss to produce mechanical hardness testers. In 1961, their first product, BS-61, was released. Brigitte Wirth and Peter Strobel took over the company in 1993. A couple of years later, in 1996, Strobel initiated the accreditation of Bareiss to be an official DKD calibration laboratory. Katrin Shen and Oliver Wirth currently lead the company.
Bareiss has a branch in Shanghai, China, which opened in 2012. In 2018, Bareiss USA was founded. Bareiss opened a third branch in Taiwan in 2020. In 2021, Bareiss North America was founded in Toronto, Canada to manage North American operations. Bareiss also opened branches in Taiwan and in Toronto, Canada in the 2020s.
Bareiss was certified by the German Accreditation Body (former German National Test Authority) to calibrate material testing machines and issue the corresponding DAkkS calibration certificates.
References
External links
Materials testing | Bareiss Prüfgerätebau GmbH | [
"Materials_science",
"Engineering"
] | 369 | [
"Materials testing",
"Materials science"
] |
69,562,138 | https://en.wikipedia.org/wiki/Eiectus | Eiectus is a potentially valid genus of extinct short-necked pliosaur that lived in the Early Cretaceous period. Fossil material has been recovered from the Wallumbilla Formation (Aptian) of Queensland was initially classified under the related genus Kronosaurus until 2021.
History
Initial discoveries
A partial skull previously assigned to Kronosaurus queenslandicus that was discovered in 1929 in the same place as the holotype of K. queenslandicus probably belonged to Eiectus, and another skull discovered in 1935 near Telemon Station in Hughenden, Queensland and prepared in May 1936 may have also belonged to Eiectus, along with all other Albian remains previously referred to K. queenslandicus.
MCZ 1285: the Harvard specimen
In 1931 the Harvard Museum of Comparative Zoology (MCZ) sent an expedition to Australia for the dual purpose of procuring specimens – the museum being "weak in Australian animals and...desires[ing] to complete its series" – and to engage in "the study of the animals of the region when alive." The Harvard Australian Expedition (1931–1932), as it became known, was a six-man venture led by Harvard Professor William Morton Wheeler, with the others being Dr. P. Jackson Darlington Jr. (a renowned coleopterist), Dr. Glover Morrill Allen and his student Ralph Nicholson Ellis, medical officer Dr. Ira M. Dixon, and William E. Schevill (a graduate-student in his twenties and Associate Curator of Invertebrate Palaeontology). MCZ director Thomas Barbour said at the time "We shall hope for specimens' of the kangaroo, the wombat, the Tasmanian devil and Tasmanian wolf," and the mission was a success with over 300 mammal and thousands of insect specimens returning to the United States. Yet Mr. Schevill, the team's fossil enthusiast, remained in Australia after the others had departed and, in the winter of 1932, was told by the rancher R.W.H. Thomas of rocks with something "odd" poking out of them on his property near Hughenden. The rocks were limestone nodules containing the most complete skeleton of Kronosaurus ever discovered. After dynamiting the nodules out of the ground (and into smaller pieces weighing approximately four tons) with the aid of a British migrant trained in the use of explosives, William Schevill had the fossils shipped back to Harvard for examination and preparation. The skull—which matched the holotype jaw fragment of K. queenslandicus—was prepared right away, but time and budget constraints put off restoration of the nearly complete skeleton – most of the bones of which remained unexcavated within the limestone blocks – for 20 years.
This interim ended when they came to the attention of Godfrey Lowell Cabot – Boston industrialist, philanthropist, and founder of the Cabot Corporation – "who was then in his nineties" and "had been interested in sea serpents since childhood." Having formerly questioned MCZ director Alfred Romer about the existence and reports of sea serpents, it thus occurred to Dr. Romer to tell Mr. Cabot about the skeleton in the museum closet. Godfrey Cabot thus asked how much a restoration would cost and "Romer, pulling a figure out of the musty air, replied, 'Oh, about $10,000.'" Romer may not have been serious but the philanthropist clearly was because the check for said sum came shortly thereafter. Two years – and more than $10,000 – later, following the careful labor of the museum preparators, the restored and mounted skeleton was displayed at Harvard in 1959. However, Dr. Romer and MCZ preparator Arnold Lewis confirmed that same year in the institution's journal Breviora that "erosion had destroyed a fair fraction of this once complete and articulated skeleton...so that approximately a third of the specimen as exhibited is plaster restoration." Furthermore, the original (real) bones are also layered in plaster; a fact that, while keeping the fossils safe, makes it difficult for paleontologists to study it – an issue which factors into the controversial question of the true size of the Kronosaurus queenslandicus.
Welles (1962) suggested that MCZ 1285 should be the neotype of what would later become Eiectus. Molnar (1982a, 1991) suggested that MCZ 1285 may not be conspecific with the holotype of Kronosaurus queenslandicus, but instead believing that it represents a second species or a new genus that differs in having a deeper and more robust skull (followed by Thulborn and Turner, 1993).
2021 revision of Kronosaurus
In 2021, a revision of K. boyacensis also transferred most of the remains of K. queenslandicus, including the Harvard remains, to a new genus and species, Eiectus longmani. The revision limits the genus Kronosaurus to the holotype mandible, and treats it as a nomen dubium. Fischer et al. (2023) criticized the reassignments even under these circumstances, predicting that they stand contrary to ICZN Articles 75.5 and 75.6 (which codifies preference for neotype designation for previously iconic taxa with non-diagnostic holotypes) and that the aforementioned multiple-species possibility cannot justify a tentative reassignment of all specimens to Eiectus. The authors instead opted to refer to all relevant fossils as Kronosaurus-Eiectus. A 2023 review of Australian fossil tetrapods restricted the name Eiectus to specimens MCZ 1285 and MCZ 1284.
References
Pliosaurids
Early Cretaceous plesiosaurs
Aptian life
Albian life
Early Cretaceous reptiles of Australia
Fossils of Australia
Fossil taxa described in 2021
Sauropterygian genera
Controversial taxa | Eiectus | [
"Biology"
] | 1,199 | [
"Biological hypotheses",
"Controversial taxa"
] |
69,562,626 | https://en.wikipedia.org/wiki/Tulio%20de%20Oliveira | Tulio de Oliveira is a Brazilian, Portuguese, and South African permanent resident professor of bioinformatics at the University of KwaZulu-Natal and Stellenbosch University, South Africa, and associate professor of global health at the University of Washington. He has studied outbreaks of chikungunya, dengue, hepatitis B and C, HIV, SARS-CoV-2, yellow fever and Zika. During the COVID-19 pandemic he led the team that confirmed the discovery of the Beta variant of the COVID-19 virus in 2020 and the Omicron variant in 2021.
He gained fellowships to the University of Oxford, Wellcome Trust Sanger Institute, and the University of Edinburgh and in 2015 was appointed professor. In 2017, he founded the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP) and in 2021 he founded the Centre for Epidemic Response and Innovation (CERI), to sequence and trace epidemics.
Early life
De Oliveira was born in Brazil. He earned a bachelor of science degree from the Federal University of Rio Grande do Sul in Brazil. He completed his MSc and PhD at the Nelson R Mandela School of Medicine, University of KwaZulu-Natal.
Career
During his career he has studied outbreaks of chikungunya, dengue, hepatitis B and C, HIV, SARS-CoV-2, yellow fever and Zika.
From 2004 to 2006 he was a Marie Curie research fellow at the University of Oxford. In 2015 he was a Newton advanced fellow at the Wellcome Trust Sanger Institute at the University of Edinburgh and in the same year was appointed professor of bioinformatics at University of KwaZulu-Natal. There, in 2017, he founded KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), which has sequenced and traced dengue, Zika, HIV and tuberculosis, in addition to SARS-CoV-2. In 2018, the year prior to completing his fellowship at Edinburgh, he was appointed as an associate professor of Global Health at the University of Washington. In July 2021, he became a professor of bioinformatics at Stellenbosch University's School for Data Science and Computational Thinking.
During the COVID-19 pandemic he led the team that confirmed the discovery of the Beta variant of the COVID-19 virus in late 2020. He has hypothesised that large groups of previously-infected people with declining immunity directly drive the emergence of variants of concern. If simultaneously there is a high level of transmission, then declining individual immunity may fail to prevent re-infection and if the virus is not cleared in enough people, new dangerous mutations may become more likely, as the virus survives and goes on to infect more people. Subsequently, as principal investigator and leader of the Network for Genomic Surveillance in South Africa, he led the team that confirmed and alerted authorities of the Omicron variant, first sequenced in Johannesburg's Lancet Laboratory, as a new variant in 2021. After first alerting authorities to the Omicron variant in South Africa, de Oliveira contended that the origin is unknown; he has "insisted that just because it was first detected in South Africa doesn't mean that's where it originated". He reported that it was possible that Omicron came from elsewhere as O. R. Tambo International Airport, Johannesburg, was the largest in Africa.
Recognition and awards
De Oliveira was included in a list of ten scientists with important roles in scientific developments in 2021 compiled by the scientific journal Nature. De Oliveira was included in a list of the leader of genomics surveillance as one of the ten breakthrough technologies in 2022 compiled by the scientific journal MIT_Technology_Review.
He received the Gold Medal Award from the South African Medical Research Council (SAMRC) in 2022.
In the same year, for his contributions to society, he received the Batho Pele Award from the Government of South Africa. His name was included in the Time's 2024 100 influential people in health.
Further reading
External links
Living people
Year of birth missing (living people)
Bioinformaticians
University of Natal alumni
Federal University of Rio Grande do Sul alumni
Brazilian scientists
Brazilian emigrants to South Africa
University of KwaZulu-Natal alumni
Academic staff of the University of KwaZulu-Natal
Academic staff of Stellenbosch University
University of Washington faculty
References | Tulio de Oliveira | [
"Biology"
] | 903 | [
"Bioinformatics",
"Bioinformaticians"
] |
69,562,680 | https://en.wikipedia.org/wiki/Samarium%28III%29%20phosphide | Samarium(III) phosphide is an inorganic compound of samarium and phosphorus with the chemical formula SmP.
Synthesis
Samarium(III) phosphide can be obtained by heating samarium and phosphorus:
4 Sm + P4 → 4 SmP
Physical properties
Samarium(III) phosphide forms crystals of a cubic system, space group Fm3m, cell size a = 0.5760 nm, Z = 4, with a structure similar to sodium chloride NaCl.
The compound exists in the temperature range of 1315–2020 °C and has a homogeneity region described by the SmP1÷0.982.
Chemical properties
Samarium(III) phosphide readily dissolves in nitric acid.
Uses
Samarium(III) phosphide compound is a semiconductor used in high power, high frequency applications and in laser diodes.
References
Phosphides
Samarium(III) compounds
Semiconductors
Rock salt crystal structure | Samarium(III) phosphide | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 201 | [
"Electrical resistance and conductance",
"Physical quantities",
"Semiconductors",
"Materials",
"Electronic engineering",
"Condensed matter physics",
"Solid state engineering",
"Matter"
] |
69,562,926 | https://en.wikipedia.org/wiki/Sobolev%20mapping | In mathematics, a Sobolev mapping is a mapping between manifolds which has smoothness in some sense.
Sobolev mappings appear naturally in manifold-constrained problems in the calculus of variations and partial differential equations, including the theory of harmonic maps.
Definition
Given Riemannian manifolds and , which is assumed by Nash's smooth embedding theorem without loss of generality to be isometrically embedded into as
First-order () Sobolev mappings can also be defined in the context of metric spaces.
Approximation
The strong approximation problem consists in determining whether smooth mappings from to are dense in with respect to the norm topology.
When , Morrey's inequality implies that Sobolev mappings are continuous and can thus be strongly approximated by smooth maps.
When , Sobolev mappings have vanishing mean oscillation and can thus be approximated by smooth maps.
When , the question of density is related to obstruction theory:
is dense in if and only if every continuous mapping on a from a –dimensional triangulation of into is the restriction of a continuous map from to .
The problem of finding a sequence of weak approximation of maps in is equivalent to the strong approximation when is not an integer.
When is an integer, a necessary condition is that the restriction to a -dimensional triangulation of every continuous mapping from a –dimensional triangulation of into coincides with the restriction a continuous map from to .
When , this condition is sufficient.
For with , this condition is not sufficient.
Homotopy
The homotopy problem consists in describing and classifying the path-connected components of the space endowed with the norm topology.
When and , then the path-connected components of are essentially the same as the path-connected components of : two maps in are connected by a path in if and only if they are connected by a path in , any path-connected component of and any path-connected component of intersects non trivially.
When , two maps in are connected by a continuous path in if and only if their restrictions to a generic -dimensional triangulation are homotopic.
Extension of traces
The classical trace theory states that any Sobolev map has a trace and that when , the trace operator is onto. The proof of the surjectivity being based on an averaging argument, the result does not readily extend to Sobolev mappings.
The trace operator is known to be onto when or when , is finite and . The surjectivity of the trace operator fails if or if is infinite for some .
Lifting
Given a covering map , the lifting problem asks whether any map can be written as for some , as it is the case for continuous or smooth and when is simply-connected in the classical lifting theory.
If the domain is simply connected, any map can be written as for some
when , when and
and when is compact, and .
There is a topological obstruction to the lifting when and an analytical obstruction when .
References
Further reading
https://mathoverflow.net/questions/108808/differential-of-a-sobolev-map-between-manifolds
Manifolds
Maps of manifolds
Sobolev spaces
Homotopy theory | Sobolev mapping | [
"Mathematics"
] | 646 | [
"Topological spaces",
"Topology",
"Manifolds",
"Space (mathematics)"
] |
69,563,020 | https://en.wikipedia.org/wiki/Anteholosticha | Anteholosticha is a genus of hypotrich, a group of protists.
Species
According to the World Register of Marine Species, the following species are accepted within Anteholosticha:
Anteholosticha arenicola (Kahl, 1932) Berger, 2003
Anteholosticha azerbaijanica (Alekperov & Asadullayeva, 1999) Berger, 2006
Anteholosticha eigneri Shao et al., 2009
Anteholosticha estuarii (Borror & Wicklow, 1983) Berger, 2003
Anteholosticha extensa (Kahl, 1932) Berger, 2003
Anteholosticha fasciola (Kahl, 1932) Berger, 2003
Anteholosticha gracilis (Kahl, 1932)
Anteholosticha longissima (Dragesco & Dragesco-Kernéis, 1986) Berger, 2006
Anteholosticha manca (Kahl, 1932) Berger, 2003
Anteholosticha monilata (Kahl, 1932) Berger, 2003
Anteholosticha multistilata (Kahl, 1932) Berger, 2003
Anteholosticha oculata (Mereschkowsky, 1877) Berger, 2003
Anteholosticha pulchra (Kahl, 1932) Berger, 2003
Anteholosticha scutellum (Cohn, 1866) Berger, 2006
Anteholosticha warreni (Song & Wilbert, 1997) Berger, 2003
References
Hypotrichea
Biota of Azerbaijan
Taxa described in 2003 | Anteholosticha | [
"Biology"
] | 334 | [
"Biota by country",
"Biota of Azerbaijan"
] |
69,563,062 | https://en.wikipedia.org/wiki/Korean%20bug | Korean bug is a popular aphrodisiac in China, Korea, and Southeast Asia, either eaten alive or in gelatin form. The aphrodisiac effect has not been clinically tested and is achieved by cantharidin inhibition of phosphodiesterase, protein phosphatase activity and stimulation of adrenergic receptors, which leads to vascular congestion and inflammation. Cantharidin is an unreliable and dangerous aphrodisiac. Its impact is primarily based totally on stimulation of the urogenital tract, robust pelvic hyperaemia with consequent erection or a possible priapism.
The bug is type of a beetle of Palembus dermestoides species. Medical studies have shown that it is a vector of causative agent of hymenolepiasis.
References
Aphrodisiac foods
Chinese cuisine
Korean cuisine
Insects as food
Southeast Asian cuisine | Korean bug | [
"Biology"
] | 188 | [
"Behavior",
"Sexuality stubs",
"Sexuality"
] |
69,563,120 | https://en.wikipedia.org/wiki/Lanthanum%20phosphide | Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP.
Synthesis
Lanthanum phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum:
4 La + P4 → 4 LaP
Physical properties
Lanthanum phosphide forms black crystals of a cubic system, space group Fmm, cell parameters a = 0.6025 nm, with number of formulas per unit cell Z = 4.
The crystals are very unstable and decompose in the open air.
Electronic properties
Lanthanum phosphide is an example of a strongly correlated material, complicating theoretical prediction of its properties.
According to HSE06 calculations, lanthanum phosphide has been theoretically predicted to have an indirect band gap of 0.25 eV along the Γ-X direction. According to HSE06 calculations with spin-orbit coupling, the band gap is predicted to be a direct gap of 0.72 eV at the X point. Using EVGGA, the compound is predicted to have a band gap of 0.56 eV along the Γ-X direction. FP-LAPW has predicted an indirect gap of 0.33 eV along the Γ-X direction.
Chemical properties
Lanthanum phosphide reacts with water, releasing highly toxic phosphine gas:
LaP + 3H2O → La(OH)3 + PH3
Uses
Lanthanum phosphide compound is a semiconductor used in high power, high frequency applications, and in laser diodes.
Lanthanum polyphosphide
In addition to the simple phosphide, LaP, lanthanum and phosphorus can also form phosphorus-rich compounds such as LaP2 LaP5 and LaP7.
References
Further reading
HathiTrust (no access)
Phosphides
Lanthanum compounds
Semiconductors
Rock salt crystal structure | Lanthanum phosphide | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 389 | [
"Electrical resistance and conductance",
"Physical quantities",
"Semiconductors",
"Materials",
"Electronic engineering",
"Condensed matter physics",
"Solid state engineering",
"Matter"
] |
69,563,183 | https://en.wikipedia.org/wiki/Area%20formula%20%28geometric%20measure%20theory%29 | In geometric measure theory the area formula relates the Hausdorff measure of the image of a Lipschitz map, while accounting for multiplicity, to the integral of the Jacobian of the map. It is one of the fundamental results of the field that has connections, for example, to rectifiability and Sard's theorem.
Definition: Given and , the multiplicity function , is the (possibly infinite) number of points in the preimage . The multiplicity function is also called the Banach indicatrix. Note that . Here, denotes the n-dimensional Hausdorff measure, and will denote the n-dimensional Lebesgue measure.
Theorem: If is Lipschitz and , then for any measurable ,
where
is the Jacobian of .
The measurability of the multiplicity function is part of the claim. The Jacobian is defined almost everywhere by Rademacher's differentiability theorem.
The theorem was proved first by Herbert Federer .
Sources
External links
Theorems in measure theory | Area formula (geometric measure theory) | [
"Mathematics"
] | 211 | [
"Theorems in mathematical analysis",
"Theorems in measure theory"
] |
69,563,812 | https://en.wikipedia.org/wiki/Ytterbium%28III%29%20phosphide | Ytterbium(III) phosphide is an inorganic compound of ytterbium and phosphorus with the chemical formula YbP. This is one of the phosphides of ytterbium.
Synthesis
Ytterbium and phosphine reacts in liquid ammonia to form Yb(PH2)2·5NH3, which can be decomposed to obtain ytterbium(III) phosphide:
Yb(PH2)2•5NH3 → Yb(PH2)2 + 5NH3
2Yb(PH2)2 → YbP + 2PH3 + H2
Physical properties
Ytterbium(III) phosphide decomposes at or above 550 °C:
12 YbP → 4 Yb3P2 + P4
It is soluble in hydrochloric acid, nitric acid, and aqua regia.
The compound forms black crystals of a cubic system, space group Fm3m.
Uses
The ytterbium(III) phosphide compound is a semiconductor used in high power, high frequency applications and in laser and other photo diodes.
References
Phosphides
Ytterbium(III) compounds
Semiconductors
Rock salt crystal structure | Ytterbium(III) phosphide | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 260 | [
"Electrical resistance and conductance",
"Physical quantities",
"Semiconductors",
"Materials",
"Electronic engineering",
"Condensed matter physics",
"Solid state engineering",
"Matter"
] |
69,563,987 | https://en.wikipedia.org/wiki/Workshop%20on%20Geometric%20Methods%20in%20Physics | The Workshop on Geometric Methods in Physics (WGMP) is a conference on mathematical physics focusing on geometric methods in physics. It is organized each year since 1982 in the village of Białowieża, Poland or Białystok.
WGMP is organized by the Chair of Mathematical Physics of Faculty of Mathematics, University of Białystok. Its founder and main organizer was Anatol Odzijewicz. Since the year 2022 the chairman of the Organizing Committee is Alina Dobrogowska.
Home venue of WGMP is in the heart of the Białowieża National Park. A number of social events, including campfire, an excursion to the Białowieża forest and a banquet, are usually organized during the week. Recently, conferences also take place in Białystok, in the campus of the University.
Notable participants
In the past, Workshops were attended by scientists including: Roy Glauber, Francesco Calogero, Ludvig Faddeev, Martin Kruskal, :es:Bogdan Mielnik, Emma Previato, Stanisław Lech Woronowicz, Vladimir E. Zakharov, Dmitry Anosov, :de:Gérard Emch, George Mackey, :fr:Moshé Flato, Daniel Sternheimer, Tudor Ratiu, Simon Gindikin, Boris Fedosov, :pl:Iwo Białynicki-Birula, Jędrzej Śniatycki, Askolʹd Perelomov, Alexander Belavin, Yvette Kosmann-Schwarzbach, :pl:Krzysztof Maurin, Mikhail Shubin, Kirill Mackenzie.
Special sessions
Many times special sessions were scheduled within the programme of the Workshop. In the year 2016 there was a session "Integrability and Geometry" financed by National Science Foundation. In the year 2017 there was a session dedicated to the memory and scientific achievements of S. Twareque Ali, long time participant and co-organizer of the Workshop. In the year 2018 there was a session dedicated to scientific achievements of prof. Daniel Sternheimer on the occasion of his 80th birthday. In the previous years, there were sessions dedicated to other prominent mathematicians and physicists such as S.L. Woronowicz, G. Emch, B. Mielnik, F. Berezin.
School on Geometry and Physics
Since 2012 the Workshop is accompanied by a School on Geometry and Physics, which is targeted at young researchers and graduate students. During the School several courses by leading experts in mathematical physics take place.
Proceedings
Starting at 1992, after the Workshop a volume of proceedings is published. In the recent years it was published in the series Trends in Mathematics by Birkhäuser. In 2005 a commemorative tome Twenty Years of Bialowieza: A Mathematical Anthology. Aspects of Differential Geometric Methods in Physics was published by World Scientific.
References
Further reading
External links
Conference webpage
Mathematics conferences
Physics conferences
Recurring events established in 1982
University of Białystok
Mathematical physics | Workshop on Geometric Methods in Physics | [
"Physics",
"Mathematics"
] | 630 | [
"Applied mathematics",
"Theoretical physics",
"Mathematical physics"
] |
75,417,422 | https://en.wikipedia.org/wiki/Water%20positive | Water positive is the concept of water conservation by a company, community or individual that actively contributes to the sustainable management and restoration of water resources. This involves implementing practices and technologies that reduce water consumption, improve water quality and enhance water availability. The goal of being water positive is to leave a positive impact on water ecosystems and ensure that more water is conserved and restored than is used or depleted.
Although many corporations have focused on this issue primarily within their own operations, especially in regions with low water thresholds, organizations like the Water Resilience Coalition are committed to achieving a net positive water impact by the year 2050, encompassing their entire value chain. This commitment entails optimizing not only their direct operations but also considering and improving the impact throughout their supply chain.
History
The idea of water positivity began in the construction industry in the early 2000s. This was in response to an agenda for optimizing construction practices by reducing their environmental impact through land and material reductions, as well as energy and water conservation, to produce "zero impact buildings." To conserve water, rain harvesting was considered to minimize dependence on freshwater consumption.
Interest in water positivity expanded to other domains and industries as concerns began to rise over the challenges of global freshwater scarcity. It can be coupled with the previous agenda of net zero emissions, sharing a common goal of restoring the environment through sustainable management of vital resources. Civil and corporate responsibilities aim to control resource consumption and manage waste to achieve a net positive impact. To achieve these goals, compensation incentives are introduced as credits (such as carbon credits or water-positive credits) that can be commercially exchanged between the seller (authorized carbon credit or water-positive holders) and buyers, promoting positive environmental impacts.
Like the compensation of greenhouse gases (GHG), the idea behind water positivity is to balance the water footprint by implementing measures for process efficiency, water purification, aquifer recharge, ecosystem conservation, and other water compensation projects. It focuses on managing this critical resource so that organizations contribute more to global water sustainability.
In 2023, the concept of Water Positive gained greater significance with the creation of the Water Positive Think Tank (WPTT), an initiative that brings together experts from various disciplines and regions around the world, committed to sustainable and regenerative water management. This group was formed in response to the growing urgency to implement measures that ensure the availability and quality of water resources in the near future. During the United Nations Water Conference in New York in March 2023, the founders of the WPTT recognized the call to action and the shared responsibility to drive effective solutions. In 2024, Daniele Strongone was appointed as its first president, with Esmeralda Leyva named as vice president.
Expansion
Water positivity expanded globally in the 2000s, driven partly by the United Nations Millennium Development Goals relating to access to drinking water and the need for manufacturing industries to participate in water sustainability in their production.
Beverage companies like The Coca-Cola Company and PepsiCo established water positivity commitments for water-stressed regions by investing in water efficiency and community projects. They set goals to reduce the use of potable water per liter of product production, becoming models for other industries. In June 2007, Coca-Cola announced a multi-year partnership with World Wildlife Fund(WWF) on water conservation. E. Neville Isdell, Coca-Cola's chairman and CEO, said: "Our goal is to replace every drop of water we use in our beverages and their production. For us, that means reducing the amount of water used...recycling water used for manufacturing processes so it can be safely returned to the environment, and replenishing water in communities and nature through locally relevant projects."
With the UN Sustainable Development Goals established in 2015 and growing social pressure for companies to adopt environmentally sustainable practices, more companies across various industries publicly committed to the goal of being water positive by 2030 to 2050.
The surge in commitment to this initiative occurred after 2015, when Microsoft, Google, Ecolab, Unilever, Nestlé, AB InBev, Levi's, IKEA, Cargill, BP, Gap Inc., Colgate-Palmolive, Meta, Diageo, Starbucks, Danone, IBM, Procter & Gamble, Intel and Mars proposed drastic reductions in their operational water consumption, offsetting consumption by implementing strategies such as rainwater harvesting systems, water purification, reforestation projects, and aquifer recharge, among other initiatives, focusing on improving water-stressed basins.
On August 7, 2023, Canada Ocean Racing, an offshore sailing team competing in the IMOCA Globe Series), named its new team "Be Water Positive". The team partnered with Alex Thomson Racing, which managed British solo sailor Alex Thomson’s five Vendée Globe campaigns over the past 20 years. Canada Ocean Racing's goal was to be the first Canadian team to complete the Vendée Globe and build awareness of water positivity.
Strategies
The main strategies applied by companies and entities were presented at the United Nations Conference on Water held in New York City in 2023. It is assumed that by systematically following these guidelines and with long-term commitments, various companies have set goals to be water positive within 10 to 15 years. The strategies are:
implementing technologies and processes to reduce direct and indirect water consumption through process optimization, circular production, and water recycling and reuse
offsetting the residual water footprint through projects that increase and improve the availability and quality of water in impacted basins, such as the construction of wetlands and algal farms, treatment plants, reforestation, aquifer recharge, rainwater harvesting systems, among other innovations
investing in research and development to implement new technologies that optimize water use
establishing partnerships with NGOs, local communities, and other actors to advance integrated management of shared water resources
promoting a culture of water sustainability among employees and consumers through awareness programs on the responsible use of water.
establishing compensation incentives for the application of multiple barrier purification systems such as ultrafiltration, microfiltration, nanofiltration, reverse osmosis, ultraviolet radiation, or their combination that sustainably purify water and achieve water positive production goals.
Compensation
The water positive concept, through water purification using unconventional resources, was presented for the first time during the opening ceremony at the IDA 2022 World Congress during the “Charting Resilient Water Solutions” opening ceremony. The initiative was presented by IDA Vice President at that time, Alejandro Sturniolo.
The objective of water footprint compensation is to achieve a positive impact on global water resources. This is done by collaborating with various stakeholders to implement water purification systems in areas of scarcity, thus increasing the local supply. A more balanced trade in virtual water footprint, which is the water used to produce traded goods and services between regions, is also promoted.
Regulating this virtual water trade can improve the global efficiency of water use. Regions with abundant water resources could compensate part of the water footprint from regions with high water stress, thus helping to alleviate their dependence on virtual water imports. This two-pronged approach of increasing local supply and balancing trade between regions represents a comprehensive management of global water resources that only these decentralized treatments allow in a way similar to the carbon offset market.
The Water Benefit Standard
The Water Benefit Standard launched in 2014, was the first globally consistent standard that certified the positive socio-economic impacts of water projects. The principles and safeguards from this standard have been embedded into the broader framework of the Gold Standard registry for Water Benefit Certificates. This ensures that any project that may have implications on water quality or access, actively manages any risks.
References
Water management
Ecosystems | Water positive | [
"Biology"
] | 1,549 | [
"Symbiosis",
"Ecosystems"
] |
75,417,715 | https://en.wikipedia.org/wiki/25-Hydroxycholesterol | 25-Hydroxycholesterol is a derivative of cholesterol, which plays a role in various biological processes in humans and other species. It is involved in cholesterol metabolism, antivirus process, inflammatory and immune response, and survival signaling pathway. 25-hydroxycholesterol is biosynthesized from cholesterol by adding a hydroxyl group at the position 25-carbon of a steroid nucleus. This reaction is catalyzed by cholesterol 25-hydroxylase, a family of enzymes that use oxygen and a di-iron cofactor to catalyze hydroxylation reaction.
The CYP3A4 enzyme, a member of the cytochrome P450 family, can catalyze the oxidation of 25-hydroxycholesterol to 7α,25-dihydroxycholesterol, whereas 25-hydroxycholesterol can inhibit CYP4F2 mRNA expression, so that members of the cytochrome P450 family are also involved in the metabolism of 25-hydroxycholesterol besides cholesterol 25-hydroxylase.
25-hydroxycholesterol has been found in various organisms such as mice, rats, rabbits, and cows. its presence in other species has not been extensively studied.
See also
;
;
.
References
Further reading
Cholestanes
Sterols
Metabolic intermediates | 25-Hydroxycholesterol | [
"Chemistry"
] | 285 | [
"Metabolic intermediates",
"Metabolism",
"Biomolecules"
] |
75,418,219 | https://en.wikipedia.org/wiki/The%20Politics%20of%20Large%20Numbers | The Politics of Large Numbers:A History of Statistical Reasoning is a book by French statistician, sociologist and historian of science, Alain Desrosières, which was originally published in French in 1993. The English translation, by Camille Naish, was published in 1998 by Harvard University Press.
Synopsis
Alain Desrosières's ambition is to reconcile an “Internal” history of the field, focusing on theory building and data collection, with an “External” history, examining the social conditions where and why a discipline develops. In his words, applying a science-in-the-making perspective “the distinction between technical and social objects—underlying the separation between internal and external history—
disappears” (p. 5).
The work of Desrosières mobilize the French style of social analysis of cognitive forms, looking at statistics as the ensemble of concepts, methods, and practices concerned with "making up things that hold".
A central part of the book explores how
socio-political structures of France, Britain, Germany, and the
United States affect the establishment and evolution of the nationals statistical offices in these countries. The author discusses in depth how the activity of cathegorization, allocating individuals to classes, provide the encoding necessary for the realization of statistical constructs, following Durkheim's motto to 'treat social facts as things', thus creating new entities as poverty or unemployment. This project that Desrosières names 'objectification' is also offered by the author as a way to reconcile objective and subjective visions of probabilities, a dichotomy he retraces to the fourteenth-century confrontation between realists and nominalists.
Reactions
Among the critiques to this work is that it reads more as a work of sociology and political economy than as a technical account
of how statistical operations developed, and the critical balance Desrosières needs to maintain between defending the necessity and legitimacy of critical attacks on
statistical concepts and methods in the name of sociopolitical progress and the stated need for "durably solidified forms" of statistical technique and concepts.
Related readings
Ian Hacking, 2006. The Emergence of Probability : A Philosophical Study of Early Ideas about Probability, Induction and Statistical Inference. Cambridge University Press.
Theodore M. Porter, 1988. The Rise of Statistical Thinking, 1820–1900. Reprint edition. Princeton, NJ: Princeton University Press.
Stephen M. Stigler, 1986. The History of Statistics: The Measurement of Uncertainty before 1900. Cambridge, Mass.: Belknap Press.
See also
Sociology of quantification
References
1993 non-fiction books
French non-fiction books
History books about science
History of probability and statistics
Science and technology studies | The Politics of Large Numbers | [
"Mathematics",
"Technology"
] | 545 | [
"Probability and statistics",
"Science and technology studies",
"History of probability and statistics"
] |
75,419,268 | https://en.wikipedia.org/wiki/Second-order%20Jahn-Teller%20distortion%20in%20main-group%20element%20compounds | Second-order Jahn-Teller distortion (commonly known as pseudo Jahn-Teller distortion) is a singular, general, and powerful approach rigorously based in first-principle vibronic coupling interactions. It enables prediction and explication of molecular geometries that are not necessarily satisfactorily or even correctly explained by semi-empirical theories such as Walsh diagrams, atomic state hybridization, valence shell electron pair repulsion (VSEPR), softness-hardness-based models, aromaticity and antiaromaticity, hyperconjugation, etc.
The application to main-group element compounds utilizes principles of group theory and symmetry. A molecule will distort in order to maximize symmetry-allowed interactions between the highest occupied molecular orbitals and lowest unoccupied molecular orbitals, and thereby stabilize the HOMOs and destabilize the LUMOs (resulting in the overall stabilization of the molecule). The extent of second-order Jahn-Teller distortion is inversely proportional to the energy difference between orbitals. Direct products are used to determine the allowedness of a given interaction: the interaction is allowed if the product of the symmetry of the first molecular orbital, the symmetry of the vibration, and the symmetry of the second molecular orbital contains the totally symmetric irreducible representation of the molecule’s point group. For heavier main-group compounds, molecular orbital interactions are larger due to the decreasing bond strength resulting in a smaller energy difference between the interacting orbitals.
Geometries of heavier group 13 and 14 analogues of multiply bound species
Group 14 analogues of alkenes and alkynes have previously been prepared. Moving down the group, the compounds experience increasing geometric distortion, becoming increasingly trans-bent from the original linear geometry and displaying increasingly limited shortening of the multiple bond. These patterns are also observed in group 13 multiply-bonded compounds. These geometry trends are rationalized below.
Semiempirical approaches
Hybridization
This trend can be rationalized with hybridization – moving down a group, the gap between the ns and np orbitals widens and there is an increasing mismatch between valence orbital sizes. The mismatch leads to lower hybridization – that is, increased nonbonding character on each of the heavier group 13 or 14 atoms involved in multiple bonding, which manifests as increased deviation from the typically expected linear and planar geometries. This rationalization is not especially cohesive with the typical approach to multiple bonds in organic chemistry – that is, a single σ-bond and one or two π-bonds.
Double donor-acceptor bonding
This rationalization is simple and preserves the double-bond nature of the group 13 or 14 atom interaction. The multiple bond is not exactly a typical σ+π interaction; rather the two halves of the alkyne analogue are treated as singlet bent monomers and the multiple bond is treated as an aggregation between them, with the spxpy-hybridized filled orbital on one group 13 or 14 atom donating to the vacant pz of the other.
Valence bond resonating lone pair
This rationalization is consistent with valence bond theory and suggests a weakened E-E multiple bond. The electron pair is described as resonating between the two group 13 or 14 atoms, and the resonance is favored by occupation of the empty (but not mandatorily vacant) orbital.
Second-order Jahn-Teller distortion approach
Second-order Jahn-Teller distortion provides a rigorous and first-principles approach to the distortion problem. The interactions between the HOMOs and LUMOs to afford a new set of molecular orbitals is an example of second-order Jahn-Teller distortion.
Cis- and trans-pyramidalization of alkene analogues
The trans-pyramidalization distortion is taken as an example. The frontier molecular orbitals of the undistorted alkene possessing D2h symmetry have symmetries ag (HOMO-1), b2u (HOMO), b1g (LUMO), and b3u (LUMO+1). The symmetry of the trans-pyramidalization vibration is b1g. A triple product of ground state, vibrational mode, and excited state that can be taken is b2u (HOMO) x b1g (trans-pyramidalizing vibrational mode) x b3u (LUMO+1) = a1g. Since a1g is the totally symmetric representation, the b2u and b3u molecular orbitals participate in an allowed interaction through the trans-pyramidalizing vibrational mode. The molecule will distort in a trans-pyramidal fashion (into C2h symmetry) in order to enable this interaction, which produces a more stabilized HOMO and more destabilized LUMO.
This treatment can be repeated for all other combinations of HOMO-1, HOMO and LUMO, LUMO+1. Notably, it is found that the HOMO and LUMO are symmetry-disallowed to mix.
Cis- and trans-bending of alkyne analogues
This distortion can be treated in the same fashion, using the triple product to determine whether or not the distortion from the undistorted linear D∞h symmetry will produce a symmetry-allowed interaction (and therefore, whether or not the distortion will occur).
Pyramidalization and inversion of trivalent group 15 compounds and group 14 radicals
The pyramidalization and energies of inversion of group 15 :MR3 (M = N, P, As, Sb, Bi) and group 14 •MR3 molecules can also be predicted and rationalized using a second-order Jahn-Teller distortion treatment. The “parent” planar molecule possessing D3h symmetry has frontier orbitals of a2” (HOMO) and a1’ (LUMO) symmetries. The pyramidalizing vibration mode has symmetry a2”. The triple product yields the totally symmetric representation a1’, indicating that the molecule will indeed pyramidalize into C3v symmetry.
The energies of inversion can also be predicted and compared. Due to lower energy overlap between the 3p and 1s orbitals in PH3 (versus between 2p and 1s in NH3), the HOMO-LUMO energy gap in PH3 will be smaller than that of NH3. This allows for a stronger interaction between the HOMO and LUMO in second-order Jahn-Teller fashion. The distortion stabilizes the HOMO and destabilizes the LUMO, resulting in a larger barrier to inversion in PH3.
Tetrahedral geometry of tetravalent second- and third-row main-group-element hydrides
Tetravalent main-group-element hydrides of form APH4 (AP = B−, C, N+, O2+, Al−, Si, P+, and S2+, where AP is a tetravalent atom or ion) are known to distort from the square planar to tetrahedral geometry. For all APH4 systems in D4h symmetry, the ground state is a1g. The exact electronic configuration, however, is dependent on the electronegativity of the main group element. The distortion to tetrahedral geometry has b2u symmetry. For these APH4 systems, the a2u→b1g* and eu→eg* one-electron charge-transfer transitions are most active in the b2u mode.
References
Condensed matter physics
Solid-state chemistry | Second-order Jahn-Teller distortion in main-group element compounds | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 1,522 | [
"Phases of matter",
"Materials science",
"Condensed matter physics",
"nan",
"Matter",
"Solid-state chemistry"
] |
75,419,394 | https://en.wikipedia.org/wiki/Richard%20Twine%20%28sociologist%29 | Richard Twine (born 1974) is a British sociologist whose research addresses environmental sociology as well as gender, human/animal and science studies. He is noted for his "foundational" work in critical animal studies. He is a reader in sociology in the Department of History, Geography & Social Sciences at Edge Hill University, where he is the co-director of the Centre for Human-Animal Studies. He is also the chair of the Research Advisory Committee of The Vegan Society.
Career
Twine studied for a Bachelor of Arts in Sociology and Psychology at the University of Stirling, graduating in 1995, and then went on to study for a Master of Arts in Sociology at the University of Essex, which he completed in 1996. He was awarded his PhD in Sociology from Manchester Metropolitan University in 2002. His thesis, supervised by Gail Hawkes and Sue Scott and examined by Anne Witz, was entitled Ecofeminism and the 'New' Sociologies - A Collaboration Against Dualism.
After completing his studies, Twine spent a decade at Lancaster University, where he was based within the ESRC Centre for Economic and Social Aspects of Genomics. While at Lancaster, he published Animals as Biotechnology: Ethics, Sustainability and Critical Animal Studies as part of the Earthscan Science in Society Series. This was "the first book fully dedicated to" critical animal studies. It offered, in the words of one reviewer, "an impressive analysis of the biotech and meat industries from an unapologetically pro-animal perspective".
After finishing at Lancaster, Twine worked briefly at the University of Glasgow and the UCL Institute of Education. He published the collection The Rise of Critical Animal Studies: From the Margins to the Centre, co-edited with Nik Taylor, with Routledge in 2014. The same year, he joined Edge Hill University. He also published a paper in Societies in which he drew upon Sara Ahmed's notion of a feminist killjoy, coining the idea of a "vegan killjoy". Twine argues that, in a culture in which meat-eating is the norm, a vegan can, by their mere presence, challenge anthropocentric attitudes and practices, affecting the enjoyment that others have in eating animal products. This, Twine claims, can serve as "critical deconstructive work". The idea of the vegan killjoy has been widely deployed in vegan studies and related fields. His book The Climate Crisis and Other Animals, published by Sydney University Press, and his co-edited collection Violence and Harm in the Animal Industrial Complex: Human-Animal Entanglements were both released in 2024.
, Twine is a reader in sociology in the Department of History, Geography & Social Sciences at Edge Hill and co-director of the university's Centre for Human-Animal Studies.
Selected publications
Twine, Richard (2010). Animals as Biotechnology: Ethics, Sustainability and Critical Animal Studies. London: Earthscan.
Twine, Richard (2010). "Intersectional disgust? Animals and (eco)feminism". Feminism & Psychology 20 (3): 397–406. .
Twine, Richard (2012). "Revealing the 'Animal-Industrial Complex' – A Concept & Method for Critical Animal Studies?" Journal for Critical Animal Studies 10 (1): 12-39.
Twine, Richard (2014). "Vegan Killjoys at the Table—Contesting Happiness and Negotiating Relationships with Food Practices". Societies 4 (4): 623-39. .
Taylor, Nik, and Richard Twine, eds. (2014). The Rise of Critical Animal Studies: From the Margins to the Centre. London: Routledge.
Twine, Richard (2017). "Materially Constituting a Sustainable Food Transition: The Case of Vegan Eating Practice". Sociology 52 (1): 166-81. .
Twine, Richard (2024). The Climate Crisis and Other Animals. Sydney: Sydney University Press.
Hunnicutt, Gwen, Richard Twine, and Kenneth Mentor, eds. (2024). Violence and Harm in the Animal Industrial Complex: Human-Animal Entanglements. Abingdon: Routledge.
References
External links
Personal website
Living people
1974 births
British animal rights scholars
British sociologists
British veganism activists
Academics of Lancaster University
Academics of Edge Hill University
Alumni of the University of Stirling
Alumni of the University of Essex
Alumni of Manchester Metropolitan University
Environmental sociologists
British gender studies academics
Scholars of veganism
Science and technology studies scholars
Sociologists of science
Ecofeminists | Richard Twine (sociologist) | [
"Technology"
] | 921 | [
"Science and technology studies",
"Science and technology studies scholars"
] |
75,419,597 | https://en.wikipedia.org/wiki/Clavulinopsis%20aurantiocinnabarina | Clavulinopsis aurantiocinnabarina is a clavarioid fungus in the family Clavariaceae. It has been given the English names of orange spindle coral or orange worm coral. It forms cylindrical, orange fruit bodies that grow on the ground in woodland litter. It was originally described from the United States and is part of a species complex as yet unresolved.
Taxonomy
The species was originally described from Pennsylvania in 1832 by American mycologist Lewis David de Schweinitz. In 1950, it was placed in the genus Clavulinopsis by English mycologist E.J.H. Corner. Initial molecular research, based on cladistic analysis of DNA sequences, indicates that C. aurantiocinnabarina is part of a complex of related species.
Description
The fruit body of Clavulinopsis aurantiocinnabarina is cylindrical, orange to orange-red, up to 80 x 6 mm, growing singly or in small clusters. Microscopically, the basidiospores are hyaline, smooth, globose to subglobose, 5.5 to 7 by 5 to 7 μm, with a small apiculus.
Similar species
Clavulinopsis fusiformis is similarly shaped, but fruit bodies are yellow rather than orange and typically appear in dense, fasciculate (closely bunched) clusters. Clavulinopsis laeticolor is also yellow and can be distinguished by its ellipsoid spores. Clavulinopsis sulcata is closely related, but was originally described from Asia and has orange-pink fruit bodies.
Distribution and habitat
The species was initially described from Pennsylvania, but its distribution is uncertain because of confusion with similar, closely related species several of which occur in eastern North America. The species complex is widespread within this area and C. aurantiocinnabarina sensu lato has also been reported from Central America and the Caribbean, Brazil, China, and Malaysia.
The species occurs singly or in small clusters on the ground and is presumed to be saprotrophic. It typically grows in woodland.
References
Clavariaceae
Fungi described in 1832
Fungi of North America
Fungus species | Clavulinopsis aurantiocinnabarina | [
"Biology"
] | 447 | [
"Fungi",
"Fungus species"
] |
75,421,556 | https://en.wikipedia.org/wiki/Assembloid | An assembloid is an in vitro model that combines two or more organoids, spheroids, or cultured cell types to recapitulate structural and functional properties of an organ. They are typically derived from induced pluripotent stem cells. Assembloids have been used to study cell migration, neural circuit assembly, neuro-immune interactions, metastasis, and other complex tissue processes. The term "assembloid" was coined by Sergiu P. Pașca's lab in 2017.
Generation of assembloids
Assembloids were described in 2017 in a study from a laboratory at Stanford to model forebrain development. Assembloids joining ventral and dorsal forebrain neural organoids demonstrated that cortical interneurons migrate and integrate into synaptically connected cortical microcircuits. This was confirmed by multiple research groups applying similar approaches to model regionalized organoid interactions and study interneuron migration. Assembloids have subsequently been generated to model projections between brain regions, such as cortico-striatal, cortico-spinal, or retino-thalamic. Methods such as Cre recombination combined with G-deleted rabies tracing can be used to identify cells projecting within assembloids; additionally, optogenetic stimulation can demonstrate the assembly of functional neural circuits in vitro.
Assembloid formation starts with the generation of organoids. Initially, human induced pluripotent stem (hiPS) cells are aggregated to generate regionalized organoids through directed differentiation. There are multiple ways in which organoids can be assembled. Regionalized organoids can be put in close proximity resulting in their fusion to generate multi-region assembloids. Alternatively, organoids can be assembled by co-culture with other cell lineages, such as microglia or endothelial cells, or with tissue samples from animal dissection, leading to multi-lineage assembloids. Lastly, organoids can be assembled with morphogenic or organizer-like cells, thus generating polarized assembloids.
The assembloid type depends on the scientific question and the accessibility of cell types required. Major biological fields utilizing the assembloid technique include cancer, gastroenterology, cardiology, and neuroscience. For instance, there are liver assembloids, kidney assembloids, pericytes assembloids to study SARS-COVID2, endometrium assembloids, stomach and colon assembloids, and bladder assembloids.
Types
Assembloids are composed of at least two organoids and/or cells derived from stem cells or primary tissue. They can be assembled to form multi-region or multi-lineage assembloids, as described above.
A. Multi-region assembloids of the nervous system
There are techniques to guide organoid differentiation into specific regions of the nervous system. For example, fusion of thalamic and cortical neural organoids models thalamo-cortical projections of ascending sensory input while cortico-striatal assembloids generate the initial projections of motor planning circuits. Forebrain assembloids model interneuron migration into the cerebral cortex. Cortico-motor assembloids can reconstitute aspects of the cortico-spinal-muscle circuit in vitro. Finally, retinal organoids can be combined with thalamic and cortical organoids to model aspects of the ascending visual pathway.
B. Multi-lineage assembloids of the nervous system
Some cell types of interest are challenging to differentiate within organoids but can be isolated from tissue explants or derived in monolayer culture. These tissue samples or enriched cell populations can then be integrated with organoid(s) of interest to study their interaction. For example, one current limitation of organoids and assembloids is their lack of functional vasculature, which hinders the supply of nutrients and trophic factors. In a technical advancement, researchers have been able to achieve vascularization by combining neural organoids with endothelial organoids and mesenchymal cells or human embryonic stem cell-derived vascular organoids. Next, microglia-like cells derived from hiPS cells can be introduced into midbrain neural organoids to model neuro-immune interactions. Similarly, oligodendrocytes can be generated in neural organoids and then migrate from the ventral forebrain to the dorsal forebrain. Lastly, combining hiPS cell-derived intestinal organoids with neural crest cells can derive assembloids of the enteric nervous system.
Additionally, assembloids can be categorized as inter-individual or inter-species, depending on whether the organoids are combined from different stem cell lines (e.g., control with disease-associated lines) or different species, respectively. These combinations help determine what aspects of development are cell-autonomous.
Disease models and applications
Assembloids help determine the complex pathophysiology of developmental disorders. For example, Timothy syndrome, which affects L-type calcium channels, was modeled in neural assembloid experiments. When dorsal and ventral forebrain organoids were integrated into an assembloid, interneurons migrated into the dorsal cortical neurons. Timothy syndrome-derived interneurons showed impaired migration. The resulting assembloids developed hypersynchronous neuronal activity, hypothesized to be due to abnormal interneuron integration into circuits. Next, Phelan-McDermid syndrome, also known as 22q13.3 deletion syndrome, is a neurodevelopmental disorder with a high risk of autism spectrum disorder that was modeled in assembloids containing cortical and striatal organoids. This research demonstrated increased striatal medium spiny neuron activity in Phelan-McDermid-derived assembloids after fusion of striatal and cortical organoids but not in isolated striatal organoids. Rett syndrome-derived assembloids displayed hypersynchronous activity perhaps due to an increase in calretinin interneurons. Alzheimer's disease risk allele APOE4, which increases the risk of dementia, has been modeled in assembloids. APOE4-derived assembloids of neural organoids combined with microglia demonstrated increased amyloid-beta-42 secretion, a known Alzheimer biomarker. APOE4 microglia in assembloids had a more complex morphology than in two-dimensional culture and had limited amyloid-beta-42 clearance.
Limitations
Despite the research benefits of assembloids, as for any model system, they have limitations. First, assembloids, like organoids, lack vascularisation, which impairs nutrient diffusion to the surface and eventually leads to necrosis in the core, thus limiting their growth. One way to address this limitation is through transplantation. Grafting cortical organoids into the brains of laboratory rats leads to improved growth and neural development.Another critique of both assembloids and organoids is the lack of sensory input, which is important for the maturation and shaping of circuits during embryonic development. Assembloids and organoids do not currently have a blood brain barrier or immune cells, limiting the biological validity for drug screening or disease modeling.There is a temporal limitation on the investigation of clinically relevant pathophysiology; organoids most closely model initial developmental stages corresponding to fetal and infant neurodevelopment and thus may not accurately model later-onset psychiatric disorders or degenerative conditions. Future directions to address this limitation include studies to understand and accelerate developmental clocks.Next, organoids and assembloids have batch-to-batch variability. Guided differentiation methods reduce variability significantly, yet reproducibility still requires optimization. Finally, the derivation and maintenance of organoids and assembloids require expertise and can be time-intensive and expensive.
See also
Organoid
Myelinoid
Scaffold-free 3D cell culture
Induced pluripotent stem cells
References
Biological models
Stem cells
Cell culture techniques | Assembloid | [
"Chemistry",
"Biology"
] | 1,698 | [
"Biochemistry methods",
"Cell culture techniques",
"Biological models"
] |
75,421,670 | https://en.wikipedia.org/wiki/1-Methylhistamine | 1-Methylhistamine (also known as Nτ-methylhistamine (NMH)) is a metabolite of histamine.
Background
NMH is formed by Nτ-methylation of histamine, catalyzed by the enzyme Histamine N-methyltransferase.
NMH is excreted in the urine and can be measured as a biomarker of histamine activity. While NMH has some biological activity on its own, it is much weaker than histamine. It can bind to histamine receptors, still, NMH has a lower affinity and efficacy than histamine for these receptors, meaning that it binds less strongly and activates them less effectively. Depending on the receptor subtype and the tissue context, NMH may act as a partial agonist or an antagonist for some histamine receptors. NMH may have some modulatory effects on histamine signalling, but it is unlikely to cause significant allergic or inflammatory reactions by itself. NMH may also serve as a feedback mechanism to regulate histamine levels and prevent excessive histamine release.
In clinical settings, urinary NMH can be measured when systemic mastocytosis is suspected. Systemic mastocytosis and anaphylaxis are typically associated with at least a two-fold increase in urinary NMH levels, which are also increased in patients taking monoamine oxidase inhibitors and in patients on histamine-rich diets.
References
Biogenic amines
Amines
Imidazoles
Histamine
Metabolism | 1-Methylhistamine | [
"Chemistry",
"Biology"
] | 324 | [
"Biomolecules by chemical classification",
"Biogenic amines",
"Functional groups",
"Cellular processes",
"Biochemistry",
"Amines",
"Bases (chemistry)",
"Metabolism"
] |
75,422,617 | https://en.wikipedia.org/wiki/Han%20Zhong%20%28Daoist%29 | Han Zhong (韓終 or 韓眾) was a Qin dynasty (221 BCE-206 BCE) herbalist fangshi ("Method Master") and Daoist xian ("Transcendent; 'Immortal'"). In Chinese history, Qin Shi Huang, the first emperor of China, commissioned Han in 215 BCE to lead a maritime expedition in search of the elixir of life, yet he never returned, which subsequently led to the infamous burning of books and burying of scholars. In Daoist tradition, after Han Zhong consumed the psychoactive drug changpu (菖蒲, "Acorus calamus, sweet flag") for thirteen years, he grew thick body hair that protected him from cold, acquired a photographic memory, and achieved transcendence. He is iconographically represented as riding a white deer and having pendulous ears.
Terminology
The present Chinese name Han Zhong combines the common surname Hán (韓) and given name Zhōng (終) or Zhòng (眾).
Hán (韓 or 韩) has English translation equivalents of: "1. name of one of the 7 major states in Warring States period, comprising the area of present-day southeast Shanxi and central Henan, originally part of the Jin state. 2. a surname." (Kroll 2017: 151). In modern Standard Chinese usage, the word commonly translates "Korea", such as Hánguó (韓國, "Korea") or Běihán (北韓, "North Korea") (Bishop 2016: n.p.).
Zhōng (終 or 终) has English translations of: "1. end, finish, conclude … come to the end of life; death, demise. 2. all the way to the end, through to the finish; all of, the whole, complete(ly) … 3. in the end, finally, after all, in conclusion. …" (Kroll 2017: 611). Zhòng (眾 or 众) can be translated as: "1. multitude, throng; manifold; numerous, legion; throng(ing); sundry, diverse … the crowd, common run, mass of; average, normal … 2. in everyone's presence, public(ly)" (Kroll 2017: 613).
Although scholars generally believe Han Zhong (韓眾) and Han Zhong (韓終) were variant writings of one person's name, some suggest they were two individuals; the Warring States period (475–221 BCE) Transcendent Han Zhong (韓眾) and the Western Han dynasty (202 BCE-9 CE) fangshi Han Zhong (韓終) (Zhang and Unschuld 2014: 173–174).
Two honorific names below for Han Zhong are Huolin xianren (霍林仙人, Transcendent of Huolin) and Bailuxian (白鹿仙, White Deer Transcendent).
Chāng (菖) is usually limited to the Acorus name: 1. ~蒲 chāngpú, sweet-flag (Acorus calamus), sweetly scented wetland grass, used apotropaically; sometimes ref[erring] to cattail (Typha latifolia) or bulrush (Typha minima)." (Kroll 2017: 41).
Pú (蒲) occurs within several Chinese plant names: "1. sweet-flag (Acorus calamus), also 菖~ chāngpú, a wetland grass, used apotropaically; the latter also cattail (Typha latifolia) or bulrush (Typha minima). 2. ~柳 [with "willow"] púliǔ, purple willow, purple osier (Salix sinopurpurea), deciduous shrub that produces small purple catkins in early spring. 3. ~葵 [with "sunflower"] púkuí, Chinese fan palm, fountain palm (Livistona chinensis). 4. ~桃 [with "peach"] pútáo, rose-apple (Syzygium jambos). ..." (Kroll 2017: 350).
A modern dictionary of Chinese botanical nomenclature lists five Acorus terms: changpu (菖蒲, Acorus calamus), riben baichang (日本白菖, with "Japanese", A. calamus var. angustatus), shi changpu (石菖蒲, with "stone/rock", Acorus gramineus"), xiye changpu (細葉菖蒲, with "thin leaf", A. gramineus var. pusillus"), and jinxian shi changpu (金線石菖蒲, with "gold thread", A. gramineus var. variegatus") (Fèvre and Métaillé 2005: 737)
Han Zhong in Chinese literature
The Chinese classics present Han Zhong as both a historical personage and a legendary persona. The textual examples below are roughly arranged chronologically.
Chuci
The 3rd-2nd centuries BCE Chuci "Songs of Chu" mentions Han Zhong (韓眾) in two poems about shamanistic spirit journeys. The Yuan You (遠遊, Far Roaming) compares him with Fu Yue, a legendary minister under the Shang dynasty king Wu Ding (r. c. 1250–c. 1200 BCE),
I marveled how Fu Yue lived on in a star;
I admired Han Zhong for attaining Oneness.
Their bodies grew dim and faded in the distance;
They left the crowded world behind and withdrew themselves. (Hawkes 1985: 194).
The Zibei (自悲, Oppressed by Grief) poem says,
I heard South Land music and wanted to go there,
And coming to Kuaiji I rested there awhile.
There I met Han Zhong, who gave me lodging.
I asked him wherein lay the secret of heaven's Tao.
Borrowing a floating cloud to take me on my journey,
With the pale woman-rainbow as a banner to fly over it,
I harnessed the Green Dragon to it for my swift conveyance.
And off in a flash we flew, at a speed that made the eyes dim. … (Hawkes 1985: 254).
In addition, the Chuci'''s enigmatic Tianwen (Heavenly Questions) section refers to marijuana and perhaps calamus. "Where is the nine-branched weed [靡蓱九衢]? Where is the flower of the Great Hemp [枲華]?" (Hawkes 1985: 128); alternatively, "The nine-jointed calamus, And xi blossoms, where do they grow?" (Field 1986: 49).
Two Chuci poems mention white deer: "Green cyprus grass grows in between, And the rush-grass rustles and sways. White deer, roebuck and horned deer Now leap and now stand poised." ("Seven Remonstrances", Hawkes 1985: 245); "Floating on cloud and mist, we enter the dim height of heaven; Riding on white deer we sport and take our pleasure." ("Alas That My Lot Was Not Cast", Hawkes 1985: 266).
Records of the Grand Historian
Sima Qian's 1st century BCE Records of the Grand Historian mentions Han Zhong as one of five fangshi Method Masters who the first Chinese emperor Qin Shi Huang (r. 221-210 BCE) selected to lead maritime expeditions seeking legendary Daoist Transcendents and elixirs of longevity.
In 219 BCE, Xu Fu (徐福) or Xu Shi (徐巿) from Qi and others submitted a memorial to the throne requesting to search for the xian Transcendents who reportedly lived on three hidden islands in the East Sea, Penglai (蓬萊), Fangzhang (方丈), and Yingzhou (瀛洲). The emperor ordered him to take a flotilla with "several thousand young men and maidens" and locate these supernatural islands (Needham 1976: 17).
In 215 BCE, during Qin Shi Huang's fourth imperial inspection tour of northeast China, he commissioned more naval expeditions searching for Transcendental drugs. First, when the emperor was visiting Mount Jieshi (碣石山, in Hebei) he commanded Scholar Lu (盧生), from Yan, to find the Transcendent Xianmen Gao (羨門高) (Needham 1976: 18). When Lu came back from his unsuccessful mission overseas, he reported on "matters concerning ghosts and gods" to the emperor, and presented prophetic writings, one of which read: "Qin will be destroyed by hu [亡秦者胡也]." (Dawson 1994: 72). Understanding hu (胡, "foreign; barbarian") in its usual meaning, the emperor ordered General Meng Tian to lead 300,000 troops on a campaign against the Xiongnu barbarians—however, hu was eventually understood as a reference to the emperor's youngest son and hapless successor, Prince Huhai (胡亥, r. 210-207 BCE), whose name was written with the same character (Dawson 1994: 154). Second, the emperor directed Han Zhong (written 韓終, cf. below), Master Hou (侯公), and Scholar Shi (石生) to search for legendary Transcendents and their "drug of deathlessness" (僊人不死之藥) (Nienhauser 2018: 145). Their explorations never returned to China and were presumed lost.
In 213 BCE, Qin Shi Huang approved his Chancellor Li Si's proposal to suppress intellectual dissent by burning most existing books, except those on divination, agriculture, medicine, and history of the state of Qin. The rules were draconian, "Anyone who ventures to discuss [the Classic of Poetry or the Book of Documents] will be executed in the marketplace. Those who use the ancient (system) to criticize the present, will be executed together with their families. … Thirty days after the ordinance has been issued, anyone who has not burned his books will be tattooed and sentenced to hard labor." (Nienhauser 2018: 147).
In 212 BCE, the emperor became resentful that Han Zhong and the other Method Masters had repeatedly lied about being able to obtain longevity elixirs, which culminated with the mass execution of 460 scholars in the infamous burning of books and burying of scholars.
First, Scholar Lu blamed evil spirits [惡鬼] for causing the failures to find "magic mushrooms, elixirs of long life, and immortals" [芝奇藥僊], and suggested, "I hope that Your Highness will not let anyone know of the residence wherein you stay; then the elixir of long life may be obtained" (Nienhauser 2018: 149). Then, Scholars Lu and Hou secretly met and concluded that since Qin Shi Huang had never been informed of his mistakes, and was becoming more arrogant daily, his obsession with power was so extreme that they could never seek the elixir of longevity for him (Nienhauser 2018: 149). Therefore, they absconded, and when the First Emperor learned of it, he was enraged.
"I have eliminated those books which I earlier confiscated from the world and judged useless, and recruited only the literary men and practitioners of [magic] methods and techniques in great number, with the desire to bring about the great peace, and, with the practitioners of [magic] methods, to seek wonderous drugs by means of alchemy [方士欲練以求奇藥]. Now I have heard that Han Chung [written with the variant 韓眾, cf. 韓終 above] has never reported back after he left, and Hsu Fu and his associates have spent cash countable only in myriads, but the elixir is yet to be found. I am only told every day that they accused each other of embezzlement. I respected and treated lavishly Scholar Lu and his like. Now they have slandered me to substantiate my lack of virtue, I will have someone investigate all the masters in Hsien-yang, to see if any of them has spread phantom rumors to confuse the black-haired [i.e., Chinese people]." (Nienhauser 2018: 150).
He had the Imperial Scribes interrogate the various Masters, who accused and implicated one another to save themselves. The emperor selected 460 of those who had violated prohibitions, and had them trapped and executed.
Finally, in 210 BCE, the last year of Qin Shi Huang's life, Xu Fu and the remaining fangshi worried that the emperor would punish them for their failures to find longevity drugs, and made up a fish story. Xu told the emperor, "The elixir from Penglai was obtainable, but we were constantly troubled by large sharks [大鮫魚], and therefore were unable to get there. We would ask for someone skilled at archery to accompany us, so that, upon seeing the sharks, we could shoot them with automatic crossbows." (Nienhauser 2018: 153–154). Xu set sail on a final expedition but never returned. Later tradition has it that he settled in Japan (Twitchett and Loewe 1986: 78).
Following the Records of the Grand Historian, subsequent official Chinese dynastic Twenty-Four Histories retell Han Zhong's story. For instance, 111 CE Book of Han mentions him in the "Treatise on Sacrifices". "When Ch'in Shih Huang first unified the empire, he indulged in the cult of hsien immortality. Thereupon, he sent people like Hsu Fu 徐福 and Han Chung 韓終 to sea, with unmarried boys and girls, in search of hsien as well as drugs. But (these people) took the opportunity to run away and never came back. Such efforts aroused the resentment and hatred of all under heaven." (Yu 1965: 95).
Liexian zhuan
Although the 2nd century CE Liexian Zhuan (Collected Biographies of Transcendents) does not mention Han Zhong, it records calamus as one of 29 psychoactive plants consumed by Daoist adepts (Chen 2021: 18–19). Two hagiographies describe calamus-root subsistence diets. Shangqiu Zixu (商丘子胥) was a master of grain-avoidance fasting who
was fond of blowing the thirty-six-pipe mouth organ (yu) while he herded pigs. At age seventy he had neither married a wife nor grown old. When people asked about the essentials of his way of life he would say, "I only eat old thistles (shu 朮) and calamus (ch'ang-p'u) roots [菖蒲根], and drink water. In this way I don't get hungry or old, that's all." When the noble and wealthy heard of it and tried eating this diet, they could never last through a year before quitting, and claimed there must be some secret formula. (Mather 1976: 434-435)
Wu Guang (務光 or 瞀光) was a Xia dynasty loyalist who supposedly refused to serve two Shang dynasty kings four centuries apart. After refusing to work for King Tang of Shang (r. c. 1617?-1588? BCE), he committed suicide by drowning, yet miraculously reappeared to deliver a similar refusal to King Wuding of Shang (r. c. 1254-1197 BCE) (Bokenkamp 2015: 293). According to traditions, Wu Guang's ears were seven cun long (comparable with Han Zhong's pendulous ears), loved playing the jin (琴, "zither"), and subsisted on calamus roots (服蒲韭根). This uncommon term pujiu (蒲韭, "calamus"; with jiu "leek; chives"), is related with literary Chinese Yaojiu (堯韭, "Yao's leek; calamus") (Bokenkamp 2015: 295).
Baopuzi
Ge Hong's c. 318 Baopuzi (Master Who Embraces Simplicity) mentions Han Zhong (韓終) twice and medical changpu (菖蒲) five times.
The "Gold and Cinnabar" chapter lists famous elixirs of longevity, including the Han Zhong dan (韓終丹, Han Zhong's elixir), in which calamus is not an ingredient. " Varnish honey and cinnabar [漆蜜]. Fry. When taken, it can protract your years and confer everlasting vision. In full sun you will cast no shadow." (4, Ware 1966: 89). "The Genie's Pharmacopeia" chapter says, "Han Chung took sweet flag for thirteen years and his body developed hairs. He intoned ten thousand words of text each day. He felt no cold in winter, though his gown was open. To be effective, sweet flag must have grown an inch above the surrounding stones and have nine or more nodules [jie 節]. That with purple flowers is best." (11, Ware 1966: 195).
This chapter quotes the apocryphal Yuanshen qi (援神契, Key to the Sacred Foundation) for the Classic of Filial Piety, "Pepper and ginger protect against the effects of dampness, sweet flag sharpens the hearing [菖蒲益聰], sesame protracts the years, and resin puts weapons to flight." (11, Ware 1966: 177). It also describes magical rouzhi (肉芝, "flesh excrescences"), notably the fengli, a mythical flying animal, "resembling a sable, blue in color and the size of a fox" found in southern forests. It is almost impossible to slay, except for changpu suffocation, and cannot be killed by burning, chopping with an ax, or beating with an iron mace, but "It dies at once, however, if its nose is stuffed with reeds from the surface of a rock [石上菖蒲]" (11, Ware 1966: 185). "The Ultimate System" chapter mentions ancient herbal cures about which people are skeptical, including, "sweet flag and dried ginger [菖蒲乾姜] check rheumatism" (5, Ware 1966: 103).
A lost fragment of the original Baopuzi text, which was preserved in the 624 Yiwen Leiju (Collection of Literature Arranged by Categories), connects Han Zhong (韓終) with the shanzhi (山芝, Mountain Excrescence): "This is what Han Zhong consumed in order to merge with heaven and earth, prolong life, and communicate with the spirits." (Chen 2021: 22).
Shenxian zhuan
Ge Hong also compiled the c. 4th century Daoist Shenxian zhuan (Biographies of Divine Transcendents), which mentions Han Zhong in cases of two calamus-eaters.
First, in the hagiography of the Han-dynasty Transcendent Liu Gen (劉根), Han Zhong presented Liu a scripture about expelling the Three Corpses, supernatural parasites that live inside the human body and seek to hasten the death of their host. Liu explained to his student Wang Zhen (王珍) how he met Han Zhong and became his disciple.
I once entered the mountains, and in my meditations there was no state I did not reach. Later, I entered Mount Huayin. There I saw a personage riding a carriage drawn by a white deer, followed by several dozen attendants, including four jade maidens each of whom was holding a staff hung with a colored flag and was fifteen or sixteen years old. I prostrated myself repeatedly, then bowed my head and begged a word. The divine personage said to me, "Have you heard of someone called Han Zhong 韓眾?" "Truly I have heard that there is such a person, yes," I answered. The divine personage said, "I am he." (Campany 2002: 242-243)
Liu recounted his multiple failures at studying the Dao without an enlightened teacher, and pleaded for help.
The divine personage then said, "Sit, and I will tell you something. You must have the bones of a transcendent; that is why you were able to see me. But at present your marrow is not full, your blood is not warm, your breath is slight, your brains are weak, your sinews are slack, and your flesh is damp. This is why, when you ingest medicinals and circulate pneumas, you do not obtain their benefits. If you wish to achieve long life, you must first cure your illnesses; only after twelve years have passed can you ingest the drug of transcendence." Campany 2002: 243-244)
Han Zhong then summarized various methods of achieving xian Transcendence, the best of which will allow one to live for several hundred years, and said, "If you desire long life, the first thing you must do is to expel the three corpses. Once the three corpses are expelled, you must fix your aim and your thought, eliminating sensual desires." Han presented Liu with a manuscript of the Shenfang wupian (神方五篇, Divine Methods in Five Sections), which says,
The ambushing corpses always ascend to Heaven to report on people's sins on the first, fifteenth, and last days of each month. The Director of Allotted Life Spans (Siming 司命) deducts from people's accounts and shortens their life spans accordingly. The gods within people's bodies want to make people live, but the corpses want to make them die. When people die, their gods disperse; the corpses, once in this bodiless state, become ghosts, and when people sacrifice to [the dead] these ghosts obtain the offering foods. This is why the corpses want people to die. When you dream of fighting with an evil person, this is [caused by] the corpses and the gods at war [inside you]. (Campany 2002 245–246)
Following the book's instructions, Liu synthesized the elixir, ingested it, and thereby attained Transcendence.
Second, in an exception to the usual Chinese master-disciple secret teachings about consuming calamus to achieve xian Transcendence, Wang Xing (王興) was a peasant who happened to be on Mount Song and overheard the giant spirit of Han Zhong telling Emperor Wu of Han (r. 141-87 BCE) where to find the best plants.
Wang Xing was a native of Yangcheng who lived in Gourd Valley. He was a commoner who was illiterate and who had no intention of practicing the Way. When Han Emperor Wu ascended Mount Song [in 110 BCE], he climbed to the Cave of Great Stupidity, where he erected a palace for the Dao [a temporary meditation chamber and altar] and had Dong Zhongshu, Dongfang Shuo, and others fast and meditate on the gods. That night, the emperor suddenly saw a transcendent twenty feet [2 丈] tall, with ears hanging down to his shoulders. The emperor greeted him respectfully and inquired who he was. The transcendent replied, "I am the spirit of Mount Jiuyi [九疑, Nine Doubts Mountain]. I have heard that the sweet flag that grows atop rocks on the Central Marchmount here, the variety with nine joints [節] per inch, will bring one long life if ingested. So I have come to gather some." Then the spirit suddenly vanished. The emperor said to his attendants, "That was not merely someone who studies the Way and practices macrobiotics. It was surely the spirit of the Central Marchmount, saying that to instruct me." And so they all gathered sweet flag for him to ingest. After two years the emperor began feeling depressed and unhappy, so he stopped taking it. At that time many of his attendant officials were also taking it, but none could sustain the practice for very long. Only Wang Xing, who had overheard the transcendent instructing Emperor Wu to take sweet flag, harvested and ingested it without ceasing and so attained long life. Those who lived near his village, both old and young, said that he was seen there over many generations. It is not known how he ended up. (Campany 2002: 341-342)
The eminent Tang poet Li Bai (701–762) wrote "The Calamus-Gatherer of Mount Song" (嵩山采菖蒲者)", which refers to this Shenxian zhuan story about Emperor Wu of Han.
A divine person of ancient visage,
Both ears hanging down to his shoulders,
Came upon, on Song Marchmount, the Marshal One of Han,
Who considered him a Transcendent of Mount Jiuyi.
"I have come to gather calamus.
Ingesting it, one can extend one’s years."
Thus saying, suddenly he disappeared;
Obliterating his shadow, he entered the clouds and mist.
At his injunction the Thearch was not, after all, enlightened –
His final return was to the fields of Lush Mound. (Bokenkamp 2015: 296)
"Lush Mound" translates Maoling (茂陵), the mausoleum of Emperor Wu of Han.
Shangqing School tradition links Han Zhong with the provenance of several scriptures, such as the Taishang Lingbao wufu (太上靈寶五符, Five Talismans of the Numinous Treasure). The manuscript originated with Donghai Xiaotong (東海小童, Young Lad of the Eastern Sea) who gave it to his student Zhang Daoling (Campany 2002: 243, 356). He transmitted it to Han Zhong (韓終), honorifically called the Huolin xianren (霍林仙人, Transcendent of Huolin), who gave manuscript, partially written in ancient tadpole script, to the Transcendent Yue Zichang (樂子長) (Bokenkamp 2008: 1167).
Other texts
Several classics record that King Wen of Zhou (r. 1152–1050 BCE) loved to eat pungent calamus. The 239 BCE Lüshi Chunqiu says, "King Wen enjoyed pickled calamus. When Confucius learned this, he wrinkled his nose and tried them. It took him three years to be able to endure them." (Knoblock and Riegel 2000: 329). The 3rd-century BCE Legalist classic Hanfeizi compares King Wen eating calamus pickles and Chu Dao (屈到), a minister of King Kang of Chu (r. 559–545 BCE), eating water-chestnuts, neither of which is considered tasty; thus, what a person eats is not necessarily delicious (Liao 1939: 438–439).
The c. 139 BCE Huainanzi uses calamus to exemplify things that bring small benefits but great harm, "Calamus deters fleas and lice, but people do not make mats out of it because it attracts centipedes." (Major et al. 2010: 838).
Some early accounts of Han Zhong, such as this Music Bureau poem, refer to his iconographic white deer, which he usually rode or sometimes hitched to a flying chariot.
The Transcendent One, astride a white deer:
His hair is short, but his ears so long!
He leads me up Grand Floriate Mountain,
Where we pluck divine herbs, gathering Redflag.
Arriving at the Master’s gate,
We present the drugs – a jade cask full.
The master ingests these drugs:
His body is healthy in but one day.
It strengthens his hair, changing white to black;
It extends his years, lengthening his fated span. . . (Bokenkamp 2015: 296)
The early 11th-century Song dynasty Taishang lingbao zhicao pin (太上靈寶芝草品, Uppermost Numinous Treasure Catalog of Excrescence Plants) says that Han Zhong (韓眾) achieved spiritual Transcendence after eating jinqingzhi (金精芝, Metal Essence Excrescence) (Kohn 2000: 248).
Jinqingzhi (Metal Essence Excrescence) grows on Mount Hua. It has a white cap, and white birdlike clouds growing above the stem. Its flavor is sweet and pungent. It should be picked on a ren (壬, "9th of the 10 Heavenly Stems") day in October, and dried in the shade for 100 days. Anyone who eats it will live for 8,000 years. After eating this excrescence Han Zhong became a Transcendent. [金精芝生於華山白蓋莖上有白雲狀如雀雞其味甘辛十月壬日採之陰乾百日食之八千歲韓眾食之仙矣].
Later hagiographies add information that Han Zhong was a native of Deyang district (modern Chengdu, Sichuan), studied the Dao with Tianzhen huangren (天真皇人, August One of Heavenly Perfection), transmitted the Shangqing jinshu yuzi (上清金書玉字, Golden Scripture with Jade Characters), and at the end of his life ascended to heaven in broad daylight (Campany 2002: 243).
Calamus in Chinese cultureChangpu (菖蒲, "Acorus calamus, sweet flag") is a versatile plant. It is used as an ingredient in Traditional Chinese medicine, an insect repellent, an apotropaic tradition in the Dragon Boat Festival, and an ingredient in "herbal regimes designed to lead to the longevous state of Transcendent being 仙人" (Bokenkamp 2015: 293).
Traditional medicine
In Chinese herbology, the calamus is considered a "potent herb" (Campany 2002: 341). It is believed to have stimulant, tonic, antispasmodic, sedative, stomachic, and diaphoretic properties. Preparations, including calamus powder, juice, and tincture are used to treat hemoptysis, colic, menorrhagia, carbuncles, buboes, deaf ears, and sore eyes (Stuart and Smith 1911: 14).
The 3rd or 4th century Lingbao santian fang (靈寶三天方, Prescriptions of the Three Lingbao Heavens) has an early description of ingesting the calamus rhizome.
Calamus grows near marshes, in damp depressions, on riverbanks, in ditches or on the banks of lakes. It also grows in the mountains on stone. The knotty root [rhizome] with nine nodes per inch is called the Numinous Body. It is foremost in making fast its attainments and contains the vapor of the 10,000 eons. As a result, it is life-giving and nurtures seminal essence and spirit. It repels water, guards against damps, represses demons, and dissolves [spirit-incurred] calamities, [so that] Guimei 鬼魅 and Wangliang 魍魎 demons are driven into the murky dark and the spirits of the unburied dead and violently murdered dare not approach. If you ingest it without ceasing, your life span will reach a thousand thousands. (Bokenkamp 2015: 298)
Praised as a (lingcao (靈草, "celestial herb") in Daoist texts, the calamus was believed to increase longevity, improve memory, and "heal a thousand diseases" (Junqueira 2022: 458–459).
Calamus and iris Acorus calamus ("sweet flag") was commonly confused with varieties of iris. Both have sword-shaped leaves with parallel veins. The Iris pseudacorus ("yellow iris") provides a good example, its specific name pseudacorus means "false acorus" and refers to their pointed leaves.
In Chinese, the changpu ("calamus") was misidentified with the huachangpu (花菖蒲, lit. "flowering calamus", Iris ensata, "Japanese water iris") (Bokenkamp 2015: 294). The above Baopuzi description of Han Zhong eating changpu for thirteen years states that the best variety has zihua (紫花, "purple flowers"), which is obviously not the sweet flag. Acorus calamus has tiny greenish-yellow flowers on a spadix; Iris ensata has large bluish-purple copigmented flowers. Furthermore, Chinese zihua yuanwei (紫花鳶尾, "purple flower iris") is an old name for I. ensata.
The Daoist physician and pharmacologist Tao Hongjing (456–536) was apparently the first to differentiate the Japanese water iris from the calamus:
The true calamus plant has leaves with [central] ridges, like the blade of a sword. Also, in the fourth and fifth months it produces minuscule flowers. In the marshy spots near the eastern mountain streams [of Mao Shan] there is a plant called the Brook Iris 溪蓀, which, in root shape and appearance is exceedingly similar to the calamus which grows on stones. It is commonly called the 'calamus which grows on stones' 石上菖蒲 by the unknowledgeable. This is mistaken. This plant may only be used as an expectorant and to repel fleas and lice and may not be ingested. (Bokenkamp 2015: 294)
Japanese kanji characters can have different readings, categorized as either on'yomi (音読み, "pronunciation reading" from Chinese) or kun'yomi (訓読み, "semantic reading" from native Japanese), and most characters have at least two readings. Japanese clarifies the ambiguity of Chinese changpu (菖蒲) meaning both "calamus" and/or "iris" with Sino-Japanese on'yomi shōbu (菖蒲, "calamus") and native kun'yomi ayame (菖蒲, "iris").
Dragon Boat Festival
The Dragon Boat Festival, or Duanwu jie (端午節), is a traditional Chinese holiday celebrated on the fifth day of the fifth month in the lunisolar Chinese calendar, generally corresponding with late May to late June in the Gregorian calendar. This folk festival is celebrated by holding dragon boat races, praying for good luck, warding off evil demons, eating zongzi glutinous rice dumplings, and drinking realgar wine (huangjiu ["yellow wine"] dosed with arsenic sulfide).
Calamus, traditionally considered an apotropaic (averting evil) and a demonifuge (chasing away demons), is closely associated with this festival for several reasons (Bokenkamp 2015: 298–299). The Duanwu was considered the hottest day of the year, when poisonous insects, malevolent spirits, and epidemic diseases were most active. During the Dragon Boat Festival, a ubiquitous ritual in traditional Chinese households consisted of hanging up mugwort twigs and calamus leaves, tied with a red thread, above the front door, in order to ward off evil. Sometimes the root was cut into the shape of a man and worn on the person (Junqueira 2022: 458).
In addition to realgar wine, Chinese people would drink wine infused with calamus root "to ward off the damp vapors." Both calamus and iris are insect repellents, particularly useful against mosquitoes and fleas, which may have helped reduce the spread of disease. A sharply pointed calamus leaf, called a pujian (蒲劍, "calamus sword"), was considered an effective apotropaic weapon. Mugwort tigers combined with calamus swords could allegedly drive off ghostly and poisonous beings. Another reason is the resemblance of calamus leaves to swords. The Dragon Boat Festival doucao (闘草, "battle with herbs") observance may well have originated as a demon-quelling sword in some sort of religious drama (Junqueira 2022: 459).
The baicaotang (百草湯, "bath of a hundred herbs") is another Duanwu ritual. Although the herbs for this decoction varied from region to region, it often included calamus, mugwort, and mulberry leaves, and occasionally chrysanthemum flowers and peach twigs. The herbs should be picked in the early morning of the Duanwu, boiled down, and used as an herbal bath later in the afternoon (Junqueira 2022: 458).
In Japan, the Chinese Dragon Boat Festival or Double Fifth Festival is celebrated on May 5 as Tango no sekku (端午の節句). Until recently, Tango no sekku was known as Boys' Day, with a Shinto holiday counterpart of Hinamatsuri Dolls' Day or Girls' Day celebrated on March 3. In 1948, the government changed May 5 to be a national holiday called Kodomo no hi or Children's Day that includes both boys and girls (Nussbaum and Roth 2002: 948).
Japanese shōbu (菖蒲, "calamus") and ayame (菖蒲, "iris") are written with the same kanji characters. While the calamus is the traditional apotropaic plant in the Chinese Dragon Boat Festival, it was changed to the iris in the Japanese Children's Day Festival. The Chinese baicaotang calamus bath corresponds to the Japanese shōbuyu (菖蒲湯, "iris bath"). Glutinous rice dumplings, both Chinese zongzi and Japanese chimaki, are usually wrapped in bamboo leaves and steamed, but calamus leaves are specially used for the Dragon Boat Festival and iris leaves for Children's Day. While realgar wine is not a Japanese tradition, drinking iris-infused sake corresponds to calamus-infused Chinese wine in order to ward off evil during the Double Fifth Festival.
See also
Qin Shi Huang's imperial tours
Jurōjin, Japanese god of longevity, often depicted with a white deer
References
Bishop, Tom (2016), Wenlin Software for learning Chinese, version 4.2.2.
Bokenkamp, Stephen R. (2008), "Yue Zichang 樂子長", in Fabrizio Pregadio, ed., The Encyclopedia of Taoism, Routledge, 1167.
Bokenkamp, Stephen R. (2015), "The herb calamus and the transcendent Han Zhong in Taoist literature", Studies in Chinese Religions 1.4: 293–305.
Chen, Fan Pen Li (2021), "Hallucinogen Use in China", Sino-Platonic Papers 318: 1-39.
Dawson, Raymond (1994), Sima Qian, The First Emperor: Selections from the Historical Records, Oxford University Press.
Fèvre, Francine and Georges Métaillé (2005), Dictionnaire Ricci des plantes chinoises; chinois-français, latin, anglais, Association Ricci.
Field, Stephen (1986), Tian wen: a Chinese book of origins, New Directions.
Hawkes, David, tr. 1985. The Songs of the South: An Anthology of Ancient Chinese Poems by Qu Yuan and Other Poets. Penguin.
Junqueira, Luis Fernando Bernardi (2022), "Numinous Herbs: Stars, Spirits and Medicinal Plants in Late Imperial China", in Routledge Handbook of Chinese Medicine, ed. by Vivienne Lo, Michael Stanley-Baker, and Dolly Yan, Routledge, 456–472.
Knoblock, John and Jeffrey Riegel, trs. 2000. The Annals of Lü Buwei: A Complete Translation and Study. Stanford: Stanford University Press.
Kroll, Paul W. (2017), A Student's Dictionary of Classical and Medieval Chinese (rev. ed.), E.J. Brill.
Liao, W. K. [Wenkui] (1939), The Complete Works of Han Fei Tzu, Arthur Probsthain.
Major, John S., Sarah Queen, Andrew Meyer, and Harold D. Roth (2010), The Huainanzi: A Guide to the Theory and Practice of Government in Early Han China, Columbia University Press.
Mather, Richard B. (1976), Shih-shuo Hsin-yu: A New Account of Tales of the World, University of Minnesota Press.
Needham, Joseph, Ho Ping-Yü, and Lu Gwei-Djen (1976), Science and Civilisation in China. Vol. V: Chemistry and Chemical Technology. Part 3: Spagyrical Discovery and Invention: Historical Survey, from Cinnabar Elixirs to Synthetic Insulin, Cambridge University Press.
Nienhauser, William H. (2018), The Grand Scribe's Records, Volume I, The Basic Annals of Pre-Han China by Ssu-ma Ch'ien, Indiana University Press.
Nussbaum, Louis-Frédéric and Käthe Roth (2002), Japan Encyclopedia, Harvard University Press.
Stuart, G. A. and F. Porter Smith (1911), Chinese Materia Medica, Pt. 1, Vegetable Kingdom, Presbyterian Mission Press.
Twitchett, Dennis and Loewe, Michael, eds. (1986), The Cambridge History of China, Volume 1: The Ch'in and Han Empires, 221 BC–AD 220, Cambridge University Press.
Ware, James R., tr. (1966), Alchemy, Medicine and Religion in the China of A.D. 320: The Nei Pien of Ko Hung, Dover.
Yü, Ying-shih (1965), "Life and Immortality in The Mind of Han China," Harvard Journal of Asiatic Studies 25: 80–122.
Zhang, Zhibin and Paul U. Unschuld (2014), Dictionary of the Ben cao gang mu, Volume 1. Chinese Historical Illness Terminology'', University of California Press.
External links
A female Transcendent riding on a white deer, painting by Kishi Ganku, (1749-1839)
Calamus Vault, Erowid
Sweet flag / Bitterroot, Jim McDonald
Acorus calamus 菖蒲, Flora of China
3rd-century BC Chinese people
Alchemical substances
Chinese alchemists
Immortality
Life extension
Longevity myths
Qin dynasty people
Taoist immortals | Han Zhong (Daoist) | [
"Chemistry"
] | 8,991 | [
"Alchemical substances"
] |
75,422,675 | https://en.wikipedia.org/wiki/Chiglitazar | Chiglitazar (trade name Bilessglu) is a drug for the treatment of type 2 diabetes. It is a peroxisome proliferator-activated receptor (PPAR) agonist.
In China, chiglitazar is approved for glycemic control in adult patients with type 2 diabetes when used in combination with diet and exercise.
References
Carbazoles
PPAR agonists
Benzophenones
4-Fluorophenyl compounds
Anilines
Amino acid derivatives | Chiglitazar | [
"Chemistry"
] | 104 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
75,423,053 | https://en.wikipedia.org/wiki/Alkylidene%20ketene | Alkylidene ketenes are a class of organic compounds that are of the form R2C=C=C=O. They are a member of the family of heterocumulenes (R2C=(C)n=O), and are often considered an unsaturated homolog of ketenes (R2C=C=O). Sometimes referred to as methyleneketenes, these compounds are highly reactive and much more difficult to access than ketenes.
Because of their instability, alkylidene ketenes are often observed as reaction intermediates. While the parent alkylidene ketene propadienone only exists on the order of seconds in vacuum at room temperature, other more highly substituted species are stable at room temperature. A notable alkylidene ketene is carbon suboxide, of the structure O=C=C=C=O.
Properties
Despite the nature of the multiple double bonds between heavy atoms in alkylidene ketenes, they have been to shown to adopt a slightly bent geometry that is not truly fully linear. Brown et al. found via the microwave spectra of 13C-labelled propadienone the structural parameters for this species, along with observed intersystem transitions that show that it converts between equivalent bent conformations, resulting in a molecular nonrigidity. More recent studies of 1,2,3-triazole and imidazole-based alkylidene ketenes have confirmed similar bent structures via X-ray crystallography.
IR and NMR analysis of the room-temperature stable 1,2,3-triazole stabilized alkylidene ketene suggests three major resonance structures as shown below.
The alkylidene ketene group gives strong IR peaks around 2100 and 2085 cm−1, similar to previously studied trapped methyleneketenes, and indicating π-backbonding character into CO. 13C-NMR indicates a negative charge on the α-carbon, supporting the zwitterionic resonance structure (pictured center above).
Synthesis
The most common synthesis for substituted alkylidene ketenes is via the thermolysis of an alkylidene derivative of Meldrum's acid. Some other common synthetic routes are summarized below. Notably, in 2021, Severin and Hansmann both reported novel synthetic methods for room-temperature stable alkylidene ketenes via N2/CO exchange from diazoalkenes stabilized by N-heterocyclic carbenes.
Thermolysis of carboxylic acids and Meldrum's acid species
These reactions are typically done in the gas phase. Elimination of an α,β-unsaturated carboxylic acid is difficult since it requires breaking the C-H bond of an sp2 hybridized carbon. Presently, using a Meldrum's acid derivative as a starting material is the most common synthetic route for synthesizing alkylidene ketenes.
Photochemical cleavage
Alkylidene ketenes can be generated by cleaving an α,β-unsaturated carbonyl or cyclic ketene with a combination of heat and irradiation. While this transformation can occur through thermolysis, this process proceeds much more easily via photoirradiation.
Via acid anhydride pyrolysis
Pyrolysis of anhydrides and intramolecular hydrogen transfer in a propiolic acid can also make alkylidene ketenes. This particular transformation is believed to go through a propiolaldehyde intermediate that generates acetylene via carbon monoxide loss.
Via N2/CO exchange
Reacting N-heterocyclic olefins with N2O to afford various diazoolefin species, Severin and Hansmann reported a method for generating highly thermally stable alkylidene ketenes via N2/CO exchange at atmospheric pressure.
Reactions
Dimerization
Alkylidene ketenes can readily dimerize and participate in cycloaddition reactions. Often orange or red in color, these dimers can be generated both in solution and via pyrolysis. Dimer formation is typically inhibited at the low temperatures used to analyze monomer species (especially methylene ketene monomers), but once the dimers are formed, it is often impossible to convert back to its substituent monomers even via thermolysis at high temperatures.
Cycloaddition
Various cycloadducts of alkylidene ketenes can be made, including the addition of an alkylidene ketene and ketene depicted below. When reacting with either ketene or dimethylketene, the formation of the β-lactone product was favored, as this cyclization occurs via an attack on the terminal ketene carbonyl.
Reactions with nucleophiles
Alkylidene ketenes react similarly to ketenes in the presence of nucleophiles, often generating equal amounts of E and Z isomers in α,β-unsaturated esters. Secondary isomerism in pyrolytic systems can, however, result in the isolation of a thermodynamic product, as is the case with the generation of phenyl-substituted methylene ketene from a Meldrum's acid derivative and hot methanol vapor. Other alkyl substitutions can also lead to β,γ-unsaturated products. This migration of the double bond can occur via secondary photoenolization, deconjugation of unsaturated products, or isomerization to a vinylidene ketene.
Decarbonylation
Decarbonylation has been observed but is thermodynamically difficult to achieve with an activation energy of over 40 kcal mol-1. However, the overall decarbonylation of propadienone to ethyne and carbon monoxide is exothermic by 2 - 5 kcal mol−1.
As C-donor ligand for transition and main group metals
Severin reported coordination chemistry using an imidazole-stabilized alkylidene ketene. Coordination increased the C-C-CO bond angle and bond lengths, indicating increased ylidic character. Using the average CO stretching frequency as a measure of donor strength, the alkylidene ketene is weaker than its diazoolefin starting material, but stronger than N-heterocyclic carbenes.
See also
Ketene
Ketenyl anion
Propadienone
Carbon suboxide
Flash vacuum pyrolysis
References
Wikipedia Student Program
Heterocumulenes
Ketenes | Alkylidene ketene | [
"Chemistry"
] | 1,397 | [
"Functional groups",
"Ketenes"
] |
75,423,232 | https://en.wikipedia.org/wiki/Bismuth%20subhalides | Bismuth-containing solid-state compounds pose an interest to both the physical inorganic chemists as well as condensed matter physicists due to the element's massive spin-orbit coupling, stabilization of lower oxidation states, and the inert pair effect. Additionally, the stabilization of the Bi in the +1 oxidation state gives rise to a plethora of subhalide compounds with interesting electronics and 3D structures.
Overview of subhalide bismuth solid-state chemistry
Topological insulators and the relationship to bismuth solid-state chemistry
Bismuth subhalides, such as Bi4Br4 and β-Bi4I4, have been recently reported as topological insulators. Topological insulators have caught attention of physical inorganic chemists as well as condensed matter physicists due to the unique physicochemical properties emerging upon transition from bulk to surface states. Exhibiting an energy band gap of classic insulator, the edge/surface states of the material acquire dissipationless electric transport. The subject has been investigated by condensed matter physicists as well as mathematicians to provide a link between the experimental emerging properties and the modeled topology. Broadly, the material's physics pertains to the Quantum Hall effect relying upon two pillars: time-reversal symmetry and spin orbit coupling, the latter dependent on the elemental material composition. Bismuth's heavy pnictogen nature yields a large spin-orbit coupling. Additionally, when bound to heavy halogens, bismuth subhalides give rise to a low-dimensional van der Waals bonded structure, exfoliatable into nanowires.
Structure of β-Bi4I4
Low dimensional van der Waals bonded materials display a fundamental material unit, usually depicted as the simplest molecular formula obeying stoichiometry. A series of such fundamental units align in the bulk material phase due to weak van der Waals interactions. Overall, key advantages conferred by the chemical structure are the ease to scale the materials down to nanostructures under simultaneous conservation of the bulk structure and the reduction in defects amount.
Belonging to the larger class of quasi 1-dimensional van der Waals bonded materials, β-Bi4I4 has been recently reported as a novel topological insulator. The binary bismuth-iodine family class includes the known bismuth(III) iodide along with additional representatives such as α-Bi4I4, Bi14I4, Bi16I4, and Bi18I4. Having the same stoichiometric chemical formula, α-Bi4I4 and β-Bi4I4 show similar solid-state structures yet critically different physicochemical properties. Specifically, α-Bi4I4 represents the trivial insulator phase, while stacking of the bismuth atoms along the b crystallographic axis in the β-Bi4I4 phase yield a different topological insulator phase. Both isoforms crystallyse in the C2/m space group, with α-Bi4I4 having a unit cell volume almost double of its topological insulator counterpart. The β crytallographic angle is higher in the β-Bi4I4: 107.87 vs 92.96, making the β-Bi4I4 more tilted (see images above).
Synthesis
Crystal growth of β-Bi4I4 was achieved through a solid-state reaction between Bi and HgI2 in a ratio of 1:2. The mixture of solid-state precursors was sealed under dynamic vacuum in a quartz ampoule and subjected to a temperature gradient of 250 °C - 210 °C in a two-zone furnace for 20 days. Needle-like blue crystals were obtained with sizes varying from a couple of mm in length and tenths of mm in diameter.
DFT Calculations
Key to modeling the topology of a material are the special points along k-vector of the Brillouin zone, accounting for the accurate depiction of the density of states emerging from the electronics of the material. Density functional theory (DFT) analyses predicted an indirect band gap of 0.158 eV in the β-Bi4I4 phase with the valence and conduction band maxima localized at the Γ and M k-space points, respectively. Interestingly enough, the major contributors to the band structure around the Fermi level are bismuth's p orbitals of even and odd parity, thus giving the gerade and ungerade points of symmetry.
ARPES measurements
The allowed electron energies in the topological insulator were probed with the well-employed angle-resolved photoemission spectroscopy (ARPES). Γ and M space points were found to exhibit binding energies of 0.3 eV and 0.8 eV, respectively. ARPES also probed the Fermi electron velocities along the x and y axes to be 0.1(1)×106 m*s−1 and 0.60(4)×106 m*s−1. The emerging non-trivial states of the topological insulator are expected to show at the space point where the conductive and valence bands almost cross or, in other words, display the smallest band gap. This point indeed showed a binding energy of 0.06 eV as measured by ARPES. ARPES measurements on a different β-Bi4Br4 topological insulator phase show similarity to its iodine counterpart.
Subhalide complexes
A ternary rhodium-centered bipyramidal dibismuth complex is an example of subhalide complexes with interesting geometry and unusual electronic properties, particularly what has been reported as an example of Möbius aromaticity. The complex exhibits a 4-electron-5-centered bond in the central plane occupied by a Bi5 equatorial pentagon with the rhodium center in the middle. Based on the electronic analysis carried out by Ruck (2003), the bismuth bonding consists of 2-centered-2-electron bonds, namely, Bi-Rh and Bi-Br one (see structure on the right).
The electronic analysis was carried out starting with counting the available skeletal electrons. Each of the 7 bismuth atoms contribute a total of 3x7=21 electrons (3 per each atom), while Rh gives all of its 9 electrons and the 8 bridging bromide atoms yield 3 electrons each. The total skeletal electron count is thus 54. The total skeletal electron count gets distributed as follows: 2 electrons per each of the 16 2c-2e− Bi-Br bond, 2 electrons per each of the 7 2c-2e− Rh-Bi metallic bond, 2 rhodium lone pairs remaining on the Rh centre (total of 4e−), and 4 electrons for 5c-4e− bond pertaining to the central pentagon. The sum of electrons used in bonding is therefore 54. Hence, the subhalide complex is electron-precise, i.e., with all of its skeletal electrons involved in chemical bonding.
The bonding in such a system was compared to the aromatic cyclopentadienyl aromatic anion. Contrary to the π-type all in-phase orbital overlap exhibited by the organic cyclopentadienyl anion, σ-type bonding of the RhBi5 unit yields a phase change for an orbital pair (see figure).
The relative orbital energy diagram is rationalized for each of the systems relying on the Frost-Musulin mnemonic. The two lone pairs stemming from the rhodium metallic center are localized on the lowest-lying twicely degenerate set of molecular orbitals, consistent with the Möbius-type aromaticity. For reference, the electronics of the aromatic organice cyclopentadienyl unit is shown to the right of the rhodium-centered pentagonal Bi5 unit. As can be seen, Hückel rules dictate the molecular orbital splitting is inverted compared to its metallic counterpart, the highest-occupied molecular orbitals this time being twicely degenerate.
See also
Solid-state chemistry
Topological insulator
Bismuth compounds
References
Bismuth compounds
Halides
Cluster chemistry | Bismuth subhalides | [
"Chemistry"
] | 1,657 | [
"Cluster chemistry",
"Organometallic chemistry"
] |
75,424,280 | https://en.wikipedia.org/wiki/ADB-FUBHQUCA | ADB-FUBHQUCA is a synthetic cannabinoid receptor agonist that has been sold as a designer drug, first reported in 2022. It is related to the previously reported compound ADB-FUBICA but with the central indole ring system expanded to a 1,4-dihydroquinoline structure. This breaks the aromaticity of the ring system, and ADB-FUBHQUCA is relatively low in potency compared to related compounds where the aromatic core is retained.
See also
ADB-FUBIATA
S-444,823
S-777,469
SER-601
References
Cannabinoids
Designer drugs
Quinolines
4-Fluorophenyl compounds
Carboxamides
Amides
Tert-butyl compounds | ADB-FUBHQUCA | [
"Chemistry"
] | 162 | [
"Amides",
"Functional groups"
] |
75,424,903 | https://en.wikipedia.org/wiki/Phosphetene | A phosphetene is an unsaturated four-membered organophosphorus heterocycle containing one phosphorus atom. It is a heavier analog of an azetine, or dihydroazete. The first synthesis of a stable, isolable phosphetene was reported in 1985 by Mathey et al. via ring expansion of a phosphirene-metal carbonyl complex. Since then, other synthesis routes for phosphetenes have been developed such as cyclization of phosphabutadienes, [2 + 2] cycloaddition, intramolecular arrangement, addition, and through organometallic intermediates.
The latter is of interest to the application, where synthesis through organometallic intermediates led to colored phosphetene compounds that were able to be incorporated in OLED devices. Phosphetenes can also participate in reactions involving the lone pair of electrons at the phosphorus, ring opening, or ring expansion.
Nomenclature
According to the extended Hantzsch-Widman system of naming heterocyclic parent hydrides, the saturated four-membered ring containing one phosphorus atom is called a phosphetane. The presence of one double bond gives a name of phosphetene. Alternately, it can be called a dihydrophosphete, as a phosphete is the cyclobutadiene-like structure containing two double bonds.
There are different constitutional isomers possible, depending on whether the double bond is attached to the phosphorus or not. The phosphorus is assigned position number 1 of the ring, and then the other structural features can be numbered relative to it. They can be distinguished based on where the double bond is in the phosphetene (Δ1-phosphetene vs Δ2-phosphetene) or where the double bond is missing as compared with the phosphete (1,2-dihydrophosphete vs 3,4-dihydrophosphete, the latter also called 2,3-dihydrophosphete).
Synthesis
Via ring expansion
Isolation of the first phosphetene was reported by Mathey et al. in 1985 by the thermolysis of phosphirene-metal pentacarbonyl complexes in the presence of carbon monoxide. This resulted in a 34% yield of a solid phosphorus analogue of unsaturated β-lactams with orange color, where the phosphorus atom was coordinated to the metal pentacarbonyl complex. Mathey et al. then proceeded to decomplex the metal pentacarbonyl complex from the phosphetene, but oxidation at the phosphorus takes place spontaneously, resulting in a λ5σ4 1,2-dihydrophosphete oxide solid with a yellow color.
The reaction of phosphatriafulvenes with azides resulted in the ring expansion into 1H-2-iminophosphetes as reported by Regitz et al. in 1994. However, in the presence of excess azide, the Staudinger reaction can take place, which transforms the yellow λ3σ3 1H-2-iminophosphete into a λ5σ4 iminophosphorane product.
Streubel et al. (1999) explored the reaction of phosphirene-metal complexes with various reactants and found that a 1,2-dihydro-1-phosphet-2-one complex can be obtained, in a mixture with other compounds, from the reaction of phosphirene-metal complexes with diethylamine.
Via cyclization of phosphabutadienes
Ring formation from phosphabutadienes was observed in when Nielson et al. (1987) obtained 1,2-dihydrophosphetes from the reaction of 1-[bis(trimethylsilyl)amino]phosphadiene with Me3SiN3 or elemental sulfur through a 3-coordinate (methylene)phosphorane intermediate.
Grützmaker et al. (1993) reacted halogenated ylides with AlCl3 to form dihydrophosphetium salts in an intramolecular cyclization reaction. Aromaticity is restored by subsequent reaction with pyridine, then a strong base, sodium bis(trimethylsilyl)amide, to form a neutral λ5-phosphete with a highly polarized P=C bond.
An air-stable, colorless, isolable 1,2-dihydrophosphete intermediate was discovered by Angelici et al. in 1993 during the synthesis of phosphaalkynes from phosphalkenes.
Streubel et al. (1997) synthesized a η1-3,4-dihydrophosphete ligand complexed to metal pentacarbonyl from η1-2-phosphabutadiene complexes, which was in turn synthesized from the reaction of metal carbene complexes with a chlorophosphane.
Via [2 + 2] cycloaddition reactions
The formation of 1,2-dihydrophosphetes from [2 + 2] cycloaddition reactions involves the reaction of metal phosphaalkane complexes with alkenes or alkynes as reported by various groups, such as Mathey et al. (1990) and Boese et al. (1994).
Via intramolecular rearrangement
Niecke et al. (1994) reacted three equivalents of iminophosphoranes with a diyne, which resulted in a 1,2-dihydrophosphete attached to a diphosphole ring, with the formation of intermediate diphosphetene compounds.
In 1995, Fluck et al. obtained 3,4-dihydrophosphetes from the reaction of 1,3-diphosphetes with CS2, COS, or CO2.
Via addition reaction
The 2,4-diphosphoniodihydrophosphetide cation is an unusually stable synthetic intermediate discovered by Schmidpeter et al. in 1996 from the addition reaction of 1,3-diphosphoniopropenide with chlorophosphines.
Via organometallic intermediates
The synthesis of 1,2-dihydrophosphetes by Doxsee et al. in 1989 from diphenyltitanacyclobutene (prepared from Tebbe's reagent) and dichlorophenylphosphine was remarkable due to the clean synthesis and workup and the obtained white 1,2-dihydrophosphetes were inert toward oxidation and in high yield (66%). Mathey et al. (1996) also used Tebbe's reagent to prepare a novel bidentate ligand consisting of phosphorus heterocycles of 1-phosphinine-1,2-dihydrophosphetes.
Majoral et al. (1997) were able to synthesize a 1,2-dihydrophosphete-zirconium complex from intramolecular coupling of dialkynyl phosphane and zirconocene-benzyne.
The complex was then treated with an acid to yield a π-extended dihydrophosphetes. This method was applied by Hissler et al. in 2014 to observe the optical and redox properties of π-extended dihydrophosphetes. With the introduction of various electron-rich substiuents on the π-backbone, the dihydrophosphetes displayed shifting of color in the visible region varying from blue to green, which was tested in a multilayer OLED device. As of 2023, Cummins et al. have been able to synthesize free, uncomplexed phosphet-2-ones with high yield using a phosphinidene transfer agent derived from anthracene. The reactivity of the phosphet-2-ones with stabilized Wittig reagents at 100 °C led to a high yield of 1,2-dihydrophosphete products with a backbone structure that resembles Hissler's polyunsaturated dihydrophosphetes used in the OLED devices.
Reactivity
Reactivity at the phosphorus atom
Phosphetenes which have a lone pair at the phosphorus atom behaved similarly to a two-electron P-donor, such as the ability to coordinate with metals. Doxsee et al. (1991) discovered that structural changes in phosphetene metal complexes are consistent with an increased s-character of the phosphorus.
Ring-opening followed by cycloaddition
Ring-opening of phosphetenes leads to phosphabutadiene derivatives that can further react. Mathey et al. reacted 1,2-dihydrophosphete tungsten pentacarbonyl complexes at high temperatures with dienophiles through [4 + 2] cycloaddition to obtain 6-membered phosphorus heterocycles, through a masked 1-phoshabutadiene intermediate. They found from X-ray crystal structure analysis that the bond between the phosphorus and sp3 carbon is long and weak (1.904 Å), which leads to the equilibrium of the 1,2-dihydrophosphete with 1-phosphabutadiene. Doxsee et al. observed Michael addition to 1,3,4-triphenyl-1,2-dihydrophosphete with various compounds to form 6-membered phosphorus heterocycles as well.
Ring expansion
Ring strain in four-membered phosphetene rings can be released by ring expansion to five-membered phosphole rings, which were studied by Mathey et al. for the incorporation of O, S, Se, and Pt and Schmidpeter et al. for the incorporation of a phosphorus atom.
References
Wikipedia Student Program
Phosphorus heterocycles
Four-membered rings
Unsaturated compounds | Phosphetene | [
"Chemistry"
] | 2,137 | [
"Organic compounds",
"Unsaturated compounds"
] |
75,425,485 | https://en.wikipedia.org/wiki/HD%20177765 | HD 177765 is a white-hued star in the southern constellation of Sagittarius. With an apparent magnitude of 9.15, it is too faint to be seen by the naked eye from Earth, but is dimly visible using binoculars. It is located at a distance of according to Gaia EDR3 parallax measurements.
Description
The star is classified as a rapidly oscillating Ap star (roAp star). It shows super-solar abundances of chromium and strontium as well as many rare-earth elements such as europium and cerium, but is depleted of carbon and nickel. In 2012, the star was found to pulsate with a low radial velocity amplitude of 7–150 m/s and a period of 23.6 minutes, the latter being the longest out of any known roAp star at the time. Two additional pulsation frequencies were detected in 2016.
The precise stellar parameters vary from publication to publication, but the star is considered to be part of a group of evolved roAp stars with long pulsation periods, alongside β CrB A and HD 116114. The existence of this group implies a systematic shift of rare-earth emission line anomalies as roAp stars age.
References
Rapidly oscillating Ap stars
A-type stars
177765
CD-26 13816
Sagittarius (constellation)
J19070978-2619543 | HD 177765 | [
"Astronomy"
] | 297 | [
"Sagittarius (constellation)",
"Constellations"
] |
75,425,538 | https://en.wikipedia.org/wiki/HD%20166473 | HD 166473 is a rapidly oscillating Ap star (roAp star) and an α2 CVn variable located about away in the southern constellation of Corona Australis. It has the variable star designation V694 Coronae Australis (sometimes abbreviated to V694 CrA). With an apparent magnitude of 7.953, it is too faint to be seen by the naked eye from Earth, but can be observed using binoculars.
Properties
As is thought to be the case with most roAp stars, it has an overabundance of rare-earth elements as well as chromium and cobalt, solar-like levels of iron and nickel, and deficiencies in carbon and oxygen.
HD 166473 possesses one of the strongest magnetic fields of any Ap star at up to G, around ten thousand times stronger than Earth's magnetic field (0.25-0.65 G). The strength and orientation of the magnetic field is strongly correlated with the layer of the atmosphere specific elements land in. This can be seen in the difference in radial velocity variations caused by pulsations of the star, which are observed in the emission lines of different elements within the spectrum of the star. In particular, rare-earth elements show an amplitude as high as 110 m/s, while other elements including iron show no signs of variation at all.
It is also an extremely slow rotator, taking over a decade to rotate on its axis once. For comparison, the Sun's rotation period is only 25.38 days. Despite this, the magnetic properties of the star are essentially the same as that of Ap stars that rotate faster.
Observational history
Oscillations of the star were first discovered in 1987, with three distinct frequencies that each correspond to periods between 8.8 and 9.1 minutes and have low amplitudes between 0.25 and 0.49 millimagnitudes. Because the frequencies are not equally spaced apart, it cannot be explained using the oblique pulsator model, which is unusual since in general the model can accurately depict pulsations of roAp stars.
In 2003, the pulsations were further resolved into standing and travelling waves in the stellar atmosphere utilizing the VLT, making HD 166473 the first star other than the Sun for such observations to be conducted.
In 2020, the rotation period of the star was determined to be , making it only the fourth ever Ap star with a rotational period exceeding ten years whose magnetic field has been observed for an entire cycle or more.
See also
Other slow-rotating Ap stars:
GY Andromedae (HD 9996)
KQ Velorum (HD 94660)
Przybylski's star (HD 101065)
HD 187474
References
Rapidly oscillating Ap stars
A-type stars
Corona Australis
Alpha2 Canum Venaticorum variables
166473
Coronae Australis, V694
CD-37 12303
J18122583-3745092 | HD 166473 | [
"Astronomy"
] | 620 | [
"Corona Australis",
"Constellations"
] |
75,425,799 | https://en.wikipedia.org/wiki/Redmi%20S2 | The Redmi S2, also known as Redmi Y2 in India, is a budget smartphone released by Xiaomi under the series Redmi in May 2018. It is the successor to Redmi Y1.
Reception
Amritanshu Mukherjee from Deccan Chronicle praised the smartphone's battery functions, design, and model, writing overall "Redmi Y2 is a great budget smartphone that ticks all the right boxes and specialises in the optics department. If you are seeking good camera performance fused in a package that is overall a great daily driver, then look no further." Ehsanur Raza Ronny from The Daily Star rated the smartphone a 6.75, stating "Xiaomi has made an excellent budget device which is jam-packed with good features." Sudhanshu Singh from TechRadar rated the smartphone 3.5 out of 5 stars, praising the smartphone's front camera features and its build, but also stating that it was "slightly bulky" and its poor handling with one hand. Subhrojit Mallick of Digit wrote "The Redmi Y2 doesn’t bring anything groundbreaking to the table. It's bland, but functional", blaming the smartphone for its image quality and battery life, but described its design as "predictable, but reliable". Khalid Anzar of Business Standard wrote the overall performance of the smartphone as a "great proposition as a selfie smartphone in the budget segment". Saurabh Singh of India Today wrote that the Redimi Y2 was "better, nay, way better than the Redmi Y1", while Karan Bajaj of The Economic Times wrote "In our opinion, the Redmi Y2 proves to be a great all-rounder smartphone for its price", but also wrote that the troubling factor was "at the same price you also have the option of the Redmi Note 5. The Note 5 has a metal body, similar hardware specifications but a bigger 4,000mAh battery". The smartphone was also reviewed by Shruti Dhapola of The Indian Express, Mike Wobker of Notebookcheck, and by Hindustan Times.
References
S2
Mobile phones with multiple rear cameras
Mobile phones with infrared transmitter
Mobile phones introduced in 2018
Phablets
Discontinued smartphones | Redmi S2 | [
"Technology"
] | 463 | [
"Crossover devices",
"Mobile technology stubs",
"Phablets",
"Mobile phone stubs"
] |
75,426,159 | https://en.wikipedia.org/wiki/Redmi%206A | The Redmi 6A is a budget smartphone developed by Xiaomi as a part of the Redmi series in June 2018.
It is available in 16 GB 2 GB RAM, 32 GB 2 GB RAM, 32 GB 3 GB RAM models.
References
Android (operating system) devices
6A
Mobile phones with infrared transmitter
Mobile phones introduced in 2018 | Redmi 6A | [
"Technology"
] | 69 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
75,426,732 | https://en.wikipedia.org/wiki/Stein%20Jacobsen | Stein Bjornar Jacobsen (born 1950) is a Norwegian-American geochemist who works within cosmochemistry.
Hailing from Drammen, he finished a cand.mag. degree at the University of Oslo before studying geology in California with a Rotary grant. Jacobsen became a professor of geochemistry at Harvard University.
He was an inducted into the Norwegian Academy of Science and Letters in 1994. In 2009 he was inducted into the American Academy of Arts and Sciences, mainly for using "the distribution of long-lived and extinct radioisotopes to date the formation of the earth's core and to define the effects of core separation on the early history of the core-mantle-crust system".
References
1950 births
Living people
People from Drammen
Norwegian emigrants to the United States
Geochemists
Harvard University staff
Members of the Norwegian Academy of Science and Letters
Fellows of the American Academy of Arts and Sciences | Stein Jacobsen | [
"Chemistry"
] | 188 | [
"Geochemists"
] |
75,427,858 | https://en.wikipedia.org/wiki/Imidazole-4-acetaldehyde | Imidazole-4-acetaldehyde is a metabolite of histamine in biological species.
Biological inactivation of histamine
The process of histamine inactivation in biological species involves its metabolism through the oxidative deamination of its primary amino group. This reaction is catalyzed by the enzyme diamine oxidase (DAO). The metabolite produced from this reaction is imidazole-4-acetaldehyde.
Imidazole-4-acetaldehyde is then further oxidized by a NAD-dependent aldehyde dehydrogenase, leading to imidazole-4-acetic acid.
Synthesis under prebiotic conditions
Under prebiotic conditions, imidazole-4-acetaldehyde can be synthesized from erythrose, formamidine, formaldehyde, and ammonia.
Role in fungal amine oxidase and bacterial aldehyde oxidase
In a study of imidazole-4-acetaldehyde presence in the reaction mixture during the coupling reaction of fungal amine oxidase and bacterial aldehyde oxidase for histamine elimination, imidazole 4-acetaldehyde was not detected, which suggests that imidazole 4-acetaldehyde was not produced as a result of the coupling reaction between fungal amine oxidase and aldehyde oxidase, as such, its absence in the reaction mixture implies that the fungal amine oxidase-aldehyde oxidase coupling reaction likely proceeded directly from histamine to imidazole-4-acetic acid with an apparent yield of 100%, without the intermediate formation of imidazole 4-acetaldehyde.
Postoperative opioid prediction
In a 2022 observational study aimed to identify preoperative serum metabolites that could predict postoperative opioid consumption, the role of imidazole-4-acetaldehyde was identified as one of the metabolites that showed different trends between gastric cancer patients with high postoperative opioid consumption and those with low opioid consumption group. The results suggest that imidazole-4-acetaldehyde, along with other metabolites, was significantly different between the two groups, so that that imidazole-4-acetaldehyde may serve as a potential biomarker for predicting postoperative opioid consumption in gastric cancer patients, still, the results of this study is inconclusive.
References
Biogenic amines
Amines
Imidazoles
Histamine
Metabolism
Aldehydes | Imidazole-4-acetaldehyde | [
"Chemistry",
"Biology"
] | 554 | [
"Biomolecules by chemical classification",
"Biogenic amines",
"Functional groups",
"Cellular processes",
"Biochemistry",
"Amines",
"Bases (chemistry)",
"Metabolism"
] |
75,428,852 | https://en.wikipedia.org/wiki/Adebrelimab | Adebrelimab is a drug that is being evaluated for the treatment of solid tumors. Adebrelimab is recombinant humanized IgG4 monoclonal antibody with specificity for PD-L1.
In 2023, adebrelimab was approved for use in China for the treatment of small cell lung cancer.
References
Cancer immunotherapy
Monoclonal antibodies | Adebrelimab | [
"Chemistry"
] | 84 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
75,430,402 | https://en.wikipedia.org/wiki/Design%20justice | Design justice is an approach to designing products, systems, and processes that attempts to address and mitigate historical inequalities, ensuring equitable outcomes for all users. This framework prioritizes the input and needs of marginalized communities throughout the design process.
Overview
A vibrant urban intersection characterized by contemporary architecture yet devoid of wheelchair ramps exemplifies the inequities present in design. While the majority of pedestrians traverse these areas with ease, those who rely on wheelchairs face barriers that underscore their exclusion. Similar instances are evident in digital environments that do not cater to colorblind individuals or in public areas that neglect the requirements of parents with strollers. These design shortcomings are not simply minor inconveniences; they perpetuate systemic inequalities, often sidelining particular demographics.
Design Justice provides a framework to confront these issues. As articulated by the Design Justice Network, it aims to “rethink design processes, center individuals who are typically marginalized by design, and employ collaborative, creative practices to tackle the most pressing challenges faced by communities.” By emphasizing the viewpoints of those historically excluded from design decisions, Design Justice seeks to redistribute power and promote inclusivity within systems, environments, and products.
Researcher Sasha Costanza-Chock highlights that Design Justice links design to broader movements for collective liberation and ecological sustainability. This methodology not only critiques conventional design frameworks but also offers practical principles for achieving equitable results.
This article investigates the role of design in perpetuating both visible and hidden inequalities. It delves into the principles of Design Justice, providing concrete examples of its implementation in reimagining public spaces, digital platforms, and consumer goods. The discussion also addresses the challenges associated with applying this framework and proposes strategies for advancing equity through design.
In a time increasingly marked by technological and creative advancements, the pertinent question is no longer whether design can impact lives, but rather how it can be utilized to foster a more just and inclusive world.
How Design Shapes Inequality
Design systems significantly shape societal frameworks, often reinforcing prevailing power structures and marginalizing specific groups. These disparities frequently remain unnoticed by those who are not directly affected, thereby perpetuating systemic inequalities.
Urban Planning and Physical Accessibility
Decisions made in urban planning can unintentionally exclude individuals with disabilities. For example, the lack of wheelchair-accessible ramps in public areas restricts mobility for wheelchair users, effectively sidelining them from full engagement in society. Such design decisions indicate a broader neglect of the varied needs of all community members.
Digital Platforms and Algorithmic Bias
In the digital landscape, algorithms that are developed without inclusive considerations can sustain biases. For instance, facial recognition systems have shown increased error rates for individuals with darker skin tones, resulting in misidentifications and reinforcing racial prejudices. This challenge arises from training datasets that lack diversity, underscoring the importance of inclusive data in the development of algorithms.
Healthcare Systems and Cultural Competency
Healthcare systems that do not take into account cultural and linguistic diversity can marginalize non-native speakers and minority populations. For instance, medical forms and informational resources provided solely in a dominant language can discourage non-native speakers from seeking medical assistance, thereby worsening health disparities. This deficiency in cultural competency in design fails to address the needs of diverse groups, resulting in unequal health outcomes.
Unrecognized Disparities
The inequities arising from design decisions frequently go unnoticed by those who are not personally impacted. Individuals who traverse environments or systems without obstacles may fail to perceive the difficulties faced by marginalized communities. This unawareness enables systemic disparities to continue unopposed, highlighting the necessity for inclusive design methodologies that deliberately take into account and respond to the requirements of all users. In summary, the decisions made in design significantly influence societal equity. By recognizing and addressing the ways in which design can disadvantage specific groups, society can progress toward more inclusive and equitable frameworks.
Principles of Design Justice
The principles of Design Justice provide a transformative framework aimed at addressing systemic inequalities within design processes. Grounded in the values of equity and inclusion, these principles prioritize the voices of marginalized groups, promote participatory design, highlight the importance of accessibility, and advocate for sustainable practices. By redefining the conventional design paradigm, Design Justice aspires to create systems, environments, and products that equitably serve all members of society.
A fundamental aspect of Design Justice is the emphasis on centering the experiences and requirements of individuals who are often excluded from design decisions. The Design Justice Network asserts that this entails redistributing power within design processes to elevate the voices of marginalized communities. For instance, engaging individuals with disabilities in urban planning ensures that public spaces are both accessible and inclusive, while consulting historically underrepresented groups in digital design can help mitigate algorithmic biases.
Participatory design represents another essential principle. This methodology encourages affected communities to actively engage in the design process, rather than merely receiving the outcomes. By fostering collaboration, participatory design empowers communities to develop solutions that resonate with their distinct perspectives and needs.
Sustainability is also a crucial component of Design Justice, advocating for environmentally responsible practices that do not exploit vulnerable communities or ecosystems. This principle aligns with the overarching objective of promoting both ecological and social well-being.
Lastly, accessibility is central to Design Justice. Whether in the creation of physical spaces or digital platforms, ensuring equitable access for all individuals—regardless of ability, language, or socioeconomic status—is of utmost importance. This commitment is exemplified in frameworks such as Sasha Costanza-Chock’s work, which connects Design Justice to collective liberation and systemic transformation.
Solutions: Case Studies of Justice Design
Inclusive design seeks to develop products and environments that are accessible to everyone, irrespective of their abilities or backgrounds. Numerous case studies illustrate the effective application of inclusive design principles, showcasing its potential for transformation.
A prominent example is the Xbox Adaptive Controller created by Microsoft. Acknowledging the varied needs of gamers with limited mobility, Microsoft partnered with organizations like AbleGamers and Warfighter Engaged to create a controller that caters to different physical capabilities. The outcome is a customizable device that enables a wider audience to participate in gaming, exemplifying how inclusive design can eliminate barriers within the digital entertainment sector.
Another important instance is the renovation of Blackfriars Station in London. This project integrated inclusive design elements such as step-free access, tactile paving for individuals with visual impairments, and clear signage. These improvements not only adhere to accessibility standards but also enhance the overall experience for all travelers, establishing a standard for public transportation systems.
In the digital content sphere, the radio program This American Life has started offering transcripts for its episodes, thereby making the content accessible to those with hearing impairments and individuals who prefer reading to listening. This initiative illustrates how media organizations can implement inclusive practices to engage a broader audience.
These case studies underscore the tangible advantages of inclusive design, demonstrating how considerate, user-focused strategies can result in products and environments that effectively serve a diverse population. By emphasizing inclusivity, designers can develop solutions that not only fulfill regulatory standards but also improve the quality of life for all users.
Challenges and Way Forward
The evident benefits of inclusive design are often overshadowed by various challenges that impede its broader implementation. A significant barrier is the insufficient awareness and comprehension among designers and stakeholders regarding the critical nature of inclusivity. Many professionals may lack a full understanding of the diverse requirements of users, resulting in designs that unintentionally marginalize certain demographics.
Another considerable challenge is the perception that adopting inclusive design entails higher costs and resource allocation. Organizations may hesitate to allocate funds for redesigning products or infrastructures to serve a wider audience, viewing such efforts as superfluous expenditures rather than as worthwhile investments.
Furthermore, the absence of regulatory frameworks and guidelines that enforce inclusive design practices leads to inconsistent application across different sectors. In the absence of established standards, designers may find it difficult to determine effective practices and benchmarks for inclusivity.
To overcome these obstacles, it is essential to incorporate inclusive design principles into the educational programs for designers and architects, thereby nurturing a culture of empathy and user-centered thinking from the beginning. Additionally, organizations should acknowledge the long-term advantages of inclusive design, such as expanded market reach and enhanced user satisfaction, which can surpass the initial costs of implementation.
Policymakers also have a crucial role in advancing inclusivity by creating and enforcing standards that guarantee accessibility and equity in design. Collaborative initiatives among governments, industry leaders, and advocacy organizations can facilitate the establishment of comprehensive guidelines that promote systemic change.
In summary, although obstacles to inclusive design remain, a dedicated approach to education, investment, and regulation can facilitate the development of more equitable and accessible spaces. Adopting inclusive design transcends legal requirements; it is a moral obligation aimed at fostering a society that honors and appreciates the diversity of all its constituents.
Conclusion: Designing for All
Design justice plays a crucial role in cultivating a more equitable society by ensuring that design processes and outcomes do not reinforce existing disparities but instead foster inclusivity and fairness. By prioritizing the needs and perspectives of marginalized communities, design justice confronts traditional power structures and aims to create environments, products, and systems that equitably serve all individuals.
Individuals are encouraged to critically evaluate the designs they encounter in their daily lives, recognizing how certain features may exclude or disadvantage particular groups. For example, urban areas that lack wheelchair accessibility or digital platforms that are not accommodating for the visually impaired exemplify design decisions that overlook the diverse needs of all users. By becoming aware of these challenges, individuals can advocate for more inclusive designs within their communities and workplaces.
Designers, businesses, and communities are called upon to adopt justice-centered design by implementing inclusive design principles and actively engaging marginalized groups in the design process. This collaborative approach ensures that the resulting designs effectively address the real needs and challenges faced by these communities, leading to more impactful and equitable solutions.
In summary, embracing design justice is vital for establishing a society where all individuals have equal access to opportunities and resources. By reflecting on current designs and advocating for inclusive practices, everyone can play a role in fostering a more just and equitable world.
References
Business terms
Design | Design justice | [
"Engineering"
] | 2,146 | [] |
75,430,497 | https://en.wikipedia.org/wiki/NGC%201079 | NGC 1079 is an isolated, weakly barred, grand-design spiral galaxy with transitional ring-like structures containing a number of prominent A type stars. It is located in the Fornax constellation and is part of the Eridanus supercluster. It was first observed and catalogued by the astronomer John Herschel in 1835.
Characteristics
NGC 1079 has unique characteristics when compared to other galaxies with a similar luminosity. Its H l content per unit blue luminosity is three times higher. Its mass and rotation velocity is twice as large as normal and it has a low surface brightness in its spiral arms, exterior to a high surface brightness center dominated by old stars. A study suggests these characteristics occur due to a luminous matter deficiency relative to its dynamical mass within the Holmberg radius.
Ring structure and star formation
Astronomers first identified NGC 1079's ring structure in 1996 by studying its HST ultraviolet imaging. Later studies have shown virtually all the star-formation activity in this galaxy occurs inside the ring.
See also
Other galaxies with star-forming rings include:
NGC 613
NGC 5248
NGC 4492
NGC 1300
References
Unbarred spiral galaxies
(constellation)
1079
10330
02415-2913
416-13
-5-7-17
Astronomical objects discovered in 1835
Galaxies discovered in 1835
Discoveries by John Herschel | NGC 1079 | [
"Astronomy"
] | 273 | [
"Fornax",
"Constellations"
] |
75,431,503 | https://en.wikipedia.org/wiki/Bride%27s%20Chair | In geometry, a Bride's Chair is an illustration of the Pythagorean theorem. The figure appears in Proposition 47 of Book I of Euclid's Elements. It is also known by several other names, such as the Franciscan's cowl, peacock's tail, windmill, Pythagorean pants, Figure of the Bride, theorem of the married women, and chase of the little married women.
According to Swiss-American historian of mathematics Florian Cajori, the ultimate etymology of the term "Bride's Chair" lies in a Greek homonym: "Some Arabic writers [...] call the Pythagorean theorem 'figure of the bride'." The Greek word has two relevant definitions: 'bride', and 'winged insect'. The figure of a right triangle with the three squares has reminded various writers of an insect, so the 'insect' sense of the Greek word came to be applied to right triangles with three squares, and to the Pythagorean theorem. Arabic speakers writing in Greek would often mistakenly assume the other sense of the word was intended, and would translate the phrase back into Arabic using the word for 'bride'.
A nice illustration of the Bride's Chair showing a chair upon which, according to ancient tradition, a bride might have been carried to the marriage ceremony can be seen in Sidney J. Kolpas' The Pythagorean Theorem: Eight Classic Proofs (page 3).
As a proof
The Bride's chair proof of the Pythagorean theorem, that is, the proof of the Pythagorean theorem based on the Bride's Chair diagram, is given below. The proof has been severely criticized by the German philosopher Arthur Schopenhauer as being unnecessarily complicated, with construction lines drawn here and there and a long line of deductive steps. According to Schopenhauer, the proof is a "brilliant piece of perversity".
From A, draw a line parallel to BD and CE. It will perpendicularly intersect BC and DE at K and L, respectively.
Join CF and AD, to form the triangles BCF and BDA.
Angles CAB and BAG are both right angles; therefore C, A, and G are collinear.
Angles CBD and FBA are both right angles; therefore angle ABD equals angle FBC, since both are the sum of a right angle and angle ABC.
Since AB is equal to FB, BD is equal to BC and angle ABD equals angle FBC, triangle ABD must be congruent to triangle FBC.
Since A-K-L is a straight line, parallel to BD, then rectangle BDLK has twice the area of triangle ABD because they share the base BD and have the same altitude BK, i.e., a line normal to their common base, connecting the parallel lines BD and AL.
Since C is collinear with A and G, and this line is parallel to FB, then square BAGF must be twice in area to triangle FBC.
Therefore, rectangle BDLK must have the same area as square BAGF = AB2.
By applying steps 3 to 10 to the other side of the figure, it can be similarly shown that rectangle CKLE must have the same area as square ACIH = AC2.
Adding these two results, AB2 + AC2 = BD × BK + KL × KC
Since BD = KL, BD × BK + KL × KC = BD(BK + KC) = BD × BC
Therefore, AB2 + AC2 = BC2, since CBDE is a square.
A different Bride's Chair
The name Bride's Chair is also used to refer to a certain diagram attributed to the twelfth century Indian mathematician Bhaskara II (c. 1114–1185) who used it as an illustration for the proof of the Pythagorean theorem. The description of this diagram appears in verse 129 of Bijaganita of Bhaskara II. There is a legend that Bhaskara's proof of the Pythagorean theorem consisted of only just one word, namely, "Behold!". However, using the notations of the diagram, the theorem follows from the following equation:
See also
Hsuan thu
References
Articles containing proofs
Theorem
Euclidean plane geometry
History of geometry
Theorems_in_plane_geometry | Bride's Chair | [
"Mathematics"
] | 918 | [
"History of geometry",
"Euclidean plane geometry",
"Mathematical objects",
"Equations",
"Theorems in plane geometry",
"Pythagorean theorem",
"Theorems in geometry",
"Geometry",
"Articles containing proofs",
"Planes (geometry)"
] |
72,587,286 | https://en.wikipedia.org/wiki/Jacob%20Prize | The Jacob Prize () is an annual award presented to an active Norwegian architect, artist, craftsman, or designer who has made a lasting contribution to their field. The award is Norway's highest design award.
Since 2014, DOGA has presented the award.
Recipients
References
Norwegian awards
Design awards | Jacob Prize | [
"Engineering"
] | 60 | [
"Design",
"Design awards"
] |
72,588,259 | https://en.wikipedia.org/wiki/Rampa%20Rattanarithikul | Rampa Rattanarithikul (; born 1939) is a Thai entomologist and taxonomist. She is a leading expert on mosquitoes, having discovered 24 new species and identifying at least 420 during her career. She was the lead author of the six-volume Illustrated Keys to the Mosquitoes of Thailand. The mosquito species Anopheles rampae and Uranotaenia rampae are named for her.
Career
Rattanarithikul started her career as a lab technician in 1959 for a malaria mosquito research project of the Southeast Asia Treaty Organization (SEATO). She directed lab assistants in making preliminary identifications of specimens, mounting and labelling them, and maintaining records. Through SEATO, she worked as a taxonomist for the Smithsonian Institution's mosquito collection during the summer of 1965. By the early 1970s, she had become a senior laboratory technician. She then worked as a medical entomologist with the Armed Forces Research Institute of Medical Sciences (AFRIMS). With AFRIMS, she studies vector species and maintains a mosquito collection at the AFRIMS museum in Bangkok.
She studied medical entomology and Japanese in Kobe University in Japan, earning her doctorate in 1996.
Specimens that Rattanarithikul have collected number in the hundreds of thousands. Many of her specimens were sent to the Walter Reed Biosystematics Unit at the Smithsonian Institution, and her contributions account for as much as half of their 1.5 million specimens. During her career, she discovered 24 new species and identified at least 420 species of mosquito.
Rattanarithikul is the lead author of the Illustrated Keys to the Mosquitoes of Thailand, a six-volume work detailing the distribution and characteristics of mosquitoes in Thailand. It was published by The Southeast Asian Journal of Tropical Medicine and Public Health in 2006. She has also consulted for a project to develop a national entomology collection for Thailand at the Queen Sirikit Botanical Garden.
Awards and honours
Rattanarithikul was presented with the American Mosquito Control Association's John N. Belkin Memorial Award in 2011 for "meritorious contributions to the field of mosquito systematics and/or biology".
Two species of mosquito are named after Rattanarithikul, the Rampa Thai Nail Mosquito (Anopheles rampae) and Uranotaenia rampae. The subgenus Rampamyia is also named for her.
Personal life
Rattanarithikul lives in Chiang Mai. Her husband is Manop Rattanarithikul, a lawyer and malaria expert.
She founded the Museum of World Insects and Natural Wonders in Chiang Mai with her husband in 1999. The museum serves as a cabinet of curiosities for their collection of fossils, petrified wood, stones, and carvings as well as insect species. The museum has 10,000 species from 315 genera.
Selected publications
References
1939 births
Living people
Entomologists
Women entomologists
21st-century Thai scientists
21st-century Thai women scientists
Kobe University alumni
People from Chiang Mai province
Taxonomists | Rampa Rattanarithikul | [
"Biology"
] | 613 | [
"Taxonomists",
"Taxonomy (biology)"
] |
72,588,402 | https://en.wikipedia.org/wiki/Bis%282-chloroethyl%29sulfide | Bis(2-chloroethyl)sulfide is the organosulfur compound with the formula . It is a prominent member of a family of cytotoxic and blister agents known as mustard agents. Sometimes referred to as mustard gas, the term is technically incorrect: bis(2-chloroethyl)sulfide is a liquid at room temperature. In warfare it was dispersed in the form of a fine mist of liquid droplets.
Synthesis
Bis(2-chloroethyl)sulfide has been prepared in a variety of ways. In the Depretz method, sulfur dichloride is treated with ethylene:
In the Levinstein process, disulfur dichloride is used instead:
+ S8
In the Meyer method, thiodiglycol is produced from chloroethanol and potassium sulfide, and the resulting diol is then treated with phosphorus trichloride:
In the Meyer–Clarke method, concentrated hydrochloric acid (HCl) is used instead of PCl3:
Thionyl chloride and phosgene, the latter of which is also a choking agent, have also been used as chlorinating agents. These compounds have the added advantage in that if they are used in excess, they remain as impurities in the finished product and can therefore produce additional mechanisms of toxicity.
Reactions
The idealized combustion of mustard gas in oxygen produces hydrochloric acid and sulfuric acid, in addition to carbon dioxide and water:
Bis(2-chloroethyl)sulfide reacts with sodium hydroxide, giving divinyl sulfide:
Sodium ethoxide acts similarly.
Safety
Upon skin contact or inhalation, bis(2-chloroethyl)sulfide is a nonspecific toxin. It is a strong alkylating agent, which affects DNA, RNA, and proteins.
See also
Bis(chloromethyl) ether
Half mustard
Nitrogen mustard
References
Thioethers
Organochlorides
Blister agents
World War I chemical weapons
IARC Group 1 carcinogens
Chloroethyl compounds
Sulfur mustards | Bis(2-chloroethyl)sulfide | [
"Chemistry"
] | 441 | [
"Blister agents",
"World War I chemical weapons",
"Chemical weapons"
] |
72,589,064 | https://en.wikipedia.org/wiki/Diot%C3%ADma%20%28website%29 | Diotíma (formerly Diotima: Materials for the Study of Women and Gender in the Ancient World) is an online resource about "women, gender, sex, sexualities, race, ethnicity, class, status, masculinity, enslavement, disability, and the intersections among them in the ancient Mediterranean world." It is on the server of Women's Classical Caucus, and named after Diotima of Mantinea. It has been favorably reviewed as a resource in the field of classical studies. Founded in 1995, it was the first online portal about women and gender in the ancient world. It was initially edited by Suzanne Bonefas and Ross Scaife; in 2019, Serena Witzke became the editor and moved it to a new URL.
References
External links
Computing in classical studies
Digital humanities projects
Projects established in 1995
Educational projects | Diotíma (website) | [
"Technology"
] | 178 | [
"Computing in classical studies"
] |
72,589,256 | https://en.wikipedia.org/wiki/Medbed | According to a conspiracy theory, medbeds (an abbreviation of "medical bed" or "meditation bed") are secret beds that can miraculously heal humans and extend life. The plausibility of such devices is pseudoscience.
Videos and podcasts about medbeds have become popular on the far-right corners of Telegram, Discord, and Rumble; the videos claim, without any evidence, that there are at least three types of medbeds, located in secret military tunnels: a “holographic medbed,” which can diagnose and cure any sickness; a medbed that can regenerate missing limbs in minutes; and a third that can reverse aging.
Medbed conspiracy theories often involve claims that the devices are utilized by members of a "deep state" and billionaires and that the former President of the United States, John F. Kennedy, is still alive, lying on a medbed. Belief in these devices is popular among QAnon influencers such as Michael Protzman, Romana Didulo, and YamatoQ.
Various companies sell devices or access to beds that supposedly heal ailments via imaginary technologies while also including fine print on their websites disclaiming that no diagnoses, treatment, or cures are provided. The term "medbed" is also by one company that offers offer nightly rentals in rooms in their facilities, with “highly-energized” beds.
Origins in popular culture
Biobeds are featured throughout the Star Trek series.
Med-Bay beds are a primary driver of the plot in the 2013 film Elysium.
References
Beds
Energy therapies
Alternative medical treatments
QAnon | Medbed | [
"Biology"
] | 342 | [
"Beds",
"Behavior",
"Sleep"
] |
72,589,826 | https://en.wikipedia.org/wiki/Grevelingendam | The is a dam located in the Grevelingen sea inlet between Schouwen-Duiveland and Goeree-Overflakkee in The Netherlands. The Grevelingendam was the fourth structure constructed as part of the Delta Works.
The dam is six kilometres in length. Construction began in 1958 with the aim of delivering it in 1964. Due to several setbacks, the construction of the dam took seven years and was opened on 1 April 1965 by Minister of Transport and Water Management, Jan van Aartsen. There is a navigation lock at the southern end of the dam near Bruinisse, and nearby a control lock using a siphon system, known as the , which connects the Eastern Scheldt with the Grevelingenmeer.
The construction of the Grevelingendam permitted Dutch civil engineers and contractors to gain experience that would be necessary for the Brouwersdam, along with more complicated closure works such as those at the Haringvlietdam, and the Oosterscheldekering.
Feasibility, planning and design
Being part of the Delta Works scheme, the Grevelingendam works were conceived in response to the North Sea flood of 1953, as a result of which it was decided to close the inlets in Zeeland and South Holland. The Grevelingendam was not a specific requirement of the Dutch Delta Act of 1958 and is not primarily intended to protect against flooding. Rather, as was the case with two other Delta Works projects (the Volkerakdam and the Zandkreekdam), the Grevelingendam was designed as a secondary compartmentalisation dam with the goal of reducing tidal current velocities in four surrounding estuaries, thereby permitting easier subsequent construction of the primary dams of the Haringvlietdam, the Brouwersdam and the Oosterscheldekering.
The location of the dam had a major influence on the construction schedule. The dam is founded over much of its length on a sandbank known as the , which dries out at low tide. Between the south side of the dam and the lock, which is situated on the bank of Schouwen-Duiveland, the dam crosses a gully up to 25 metres in depth. Between the north side of the and the bank at Goeree-Overflakkee, the dam crosses a shallower, 1000 metre-wide network of gullies.
The height of the western part of the dam (the 'crown line') over the is 5.5 metres above Amsterdam Ordnance Datum (, NAP). This high crest line is necessary due to large wave run-up, with the dike designed to permit some flooding at very high water levels. Space was reserved on the crown of the dam for the conversion of the N59 into a four-lane motorway, with a parallel road for other traffic. Due to a policy change in the 1970s, the four-lane motorway was never built.
The hydraulic investigations undertaken at the design stage had shown that it was desirable to have the closure of the southern channel at the Schouwen-Duiveland coast precede the closing of the northern channel near Goeree-Overflakkee. The following construction schedule was therefore planned:
1961: Construction of the dam section on the and commencement of works in the southern channel.
1962: Closure of the southern channel and construction of the dam section through it. Commence construction in the northern channels.
1963: Closure of the northern channels and construction of the dam section.
Construction: Southern channel caisson closure
The dam closure at the southern channel was achieved using a system of caissons, with a number of the caissons that had been used for the emergency closures immediately after the North Sea flood disaster of 1953 repurposed for use. In addition to new caisson units made specially for the Grevelingendam project, a caisson unit which had been intended for use on the closure of the Brielse Maasdam in 1950 was also used. The caissons were floated to the closing gap, being transported in units of five. Before the closure, abutments were placed on both sides of the dam, composed of two caissons on the south side and three caissons on the north side, which were connected to the top of the dam sections.
When closing large gaps using caissons, the units must be placed in the closing hole during slack water, which in most cases occurs at the moment of tidal reversal (at or around the times of high water and low water). However, in the Grevelingenmeer, there were more than two turnarounds as a result of the fact that the currents in the closing gap were influenced by tides from the Oosterschelde and the Brouwershaven Gap.
The flow velocities in the closing area were therefore analysed and calculated in detail for the various caisson sinking phases, using the Deltar analogue computer, which had just been developed at the time. The time available during the turnaround made it impossible to sink the caissons individually. Therefore, two or three caissons were connected together and sunk at the same time.
During the sinking manoeuvres, the caissons were guided by a firmly anchored floating crane. After they had been sunk, armourstone was installed along the front and rear of the caissons by a stone dumping vessel (on the sea side of the dam) and a floating crane on the river side. After pouring concrete to the caisson units, the remaining elements were placed using a floating sheerleg. The unit caissons had a height of 6 metres, with the extensions being 2 metres in height. The threshold level at the closing gap was around 5 metres below sea level (Amsterdam Ordnance Datum) with the concrete barrier terminating 8 metres above this.
Construction: Northern channel closure using cable-way
The shallow nature of the northern channel permitted a more gradual closure, with the use of a 1.9 kilometre long cable car system. The advantage of a gradual vertical closure is that flow velocities are limited, resulting in a reduction in the magnitude of scour holes either side of the dam. Another advantage of the cable car solution was that only a single pylon was required in the centre of the channel. The cable car system was designed by Rijkswaterstaat in combination with the French company Neyrpic, and used self-propelled cars and a one-way system to optimise capacity.
A threshold at the base of the dam in the northern channels was poured in 1962, along with a dike section from Goeree-Overflakkee. The remaining length, of approximately 1200 metres, was constructed by the cable car method. The cableway consisted of two carrying cables, with the last sections terminating at a turntable, along which the cars could pass from one side to the other. The cables were attached to a fixed anchor point on the north-east side of the closure, which has been preserved as a monument to the construction, and to a tilting counterweight on the opposite side. The units and stone placed by the cars were transported by four steel hopper barges, being lifted and lowered by the cars. A production rate of 360 tonnes of stone per hour was achieved.
The channels were closed using the method of gradual closing, partly because loosely packed sand in the substrate could lead to settlement issues, and partly to gain experience with the use of a cable-way. Using the cable-way stone was dumped on a threshold covered with fascine mattresses, polyethylene foil, and asphalt mastic. The stone dam was built up in this way to 2.5 metres above NAP, after which sand could begin to be sprayed against the closing dam by dredgers, and the dam body raised. By the autumn of 1965, the Grevelingen Dam was completed.
The Grevelingenmeer (Lake Grevelingen)
With the Grevelingendam complete, the subsequent construction of the Brouwersdam in 1971 created the Grevelingenmeer Lake, which has become a popular water sports location for recreational diving and sea kayaking. Shipping enters the Krammer via the Grevelingen navigation lock at Bruinisse.
In order to maintain the freshwater status of the Grevelingenmeer, a siphon control lock complex was constructed in the Brouwersdam, and later a similar structure was constructed at the Grevelingendam (the ). These locks turned out to have more capacity than originally intended, and a decision was made to allow the Grevelingenmeer to remain as a seawater lake, it thus becoming the largest seawater lake in Europe. A connection to the Philipsdam was made at the South Holland end of the Grevelingendam.
Road and bridge over the dam
The N59 runs over the Grevelingendam, with a secondary bridge constructed over the Grevelingen lock to cope with increased traffic volumes.
Media
See also
Delta Works
Flood control in the Netherlands
Rijkswaterstaat
References
External links
Grevelingendam at the Watersnoodmuseum knowledge centre Information on the Grevelingendam from the official Watersnoodmuseum website
Dams in Zeeland
Dams in South Holland
Dams completed in 1965
Delta Works | Grevelingendam | [
"Physics"
] | 1,919 | [
"Physical systems",
"Hydraulics",
"Delta Works"
] |
72,590,105 | https://en.wikipedia.org/wiki/Miers%20Longstreth | Miers Fisher Longstreth (March 15, 1819 - December 27, 1891) was an American merchant, physician, and astronomer, best known as a founding member of the National Academy of Sciences.
Longstreth was born in Philadelphia and received his secondary education at Clermont Academy
(graduating 1833), then M.L. Hurlburt's Classical Academy. He left school to work in a
hardware store, becoming a full member of the firm in 1840. As early as 1837, however, he was attending
lectures at the College of Pharmacy of the University of Pennsylvania. In 1856 he completed a
medical degree at the university's Medical Department.
By happenstance, a new Friends School was established next to his and his wife's home. The school
had an astronomical observatory, which Dr. Longstreth was invited to use. He soon came to own a
5-inch aperture telescope, a transit instrument, and an astronomical clock. With these instruments,
he discovered a discrepancy in the then-accepted formulas for the position of the Moon and
improved upon them as "Longstreth's Lunar Formula", so-named by Benjamin Peirce and put
to immediate use in the American Nautical Almanac.
Longstreth was elected a member of the American Philosophical Society in 1848,
and was a founding member of the National Academy of Sciences in 1863. Throughout his life
he was a devoted member of the Society of Friends.
References
19th-century American physicians
19th-century American astronomers
United States National Academy of Sciences
University of Pennsylvania alumni | Miers Longstreth | [
"Astronomy"
] | 318 | [
"Astronomers",
"Astronomer stubs",
"Astronomy stubs"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.