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67,807,247 | https://en.wikipedia.org/wiki/Construction%20and%20Engineering%20Forces | The Construction and Engineering Forces (), also known as the Corps of Engineers, is a combat engineer branch of the Mongolian Armed Forces that specializes in military construction and civil works. They also construct defensive positions, serve as military engineering, sappers, and detect mines. They have played a leading role in Armed Forces peacekeeping missions and have successfully participated in UN peacekeeping operations and joint international training exercises.
History
Imperial era
The origin and development of the engineering army dates back to the era of the Mongol Empire. Engineers in the Mongol Army utilized unconventional techniques to win battles against enemies. Genghis Khan frequently utilized Chinese and Muslim engineers during the Khwarezmian campaign and the Sieges of Fancheng and Xiangyang.
Communist era
At the end of 1927, the 1st Cavalry Corps was entrenched as the main fighting force of the Mongolian People's Revolutionary Party, and in 1928, the first “Breakdown and Repair Sapper Branch” was established. This was the first construction army to be established in the Mongolian People's Republic. In 1947, the Military Construction Command was established, with more than 10 units. At its peak, there were 23 military construction units, totaling around 20,000 soldiers and 56,000 officers. Beginning in 1963, large-scale construction work operated as a military affair under the responsibility of the Mongolian People's Army. On January 8, 1964, the Council of Ministers established the General Construction Military Agency under the Ministry of People's Military Affairs. A large number of construction military units were established over the course of the decades that followed. Prior to the 1990s, military construction units contributed 70-80 percent of the country's construction. Five construction units were involved in the construction of Erdenet, which was established in 1974. Construction units were also responsible for developing the cities of Choibalsan and Darkhan. Between 1970 and 1990, the construction army commissioned 300-500 facilities a year.
Modern era
Work to create a new construction and engineering army began in 2010, and throughout the decade, the Ministry of Defense and the General Staff established six civil engineering units in the 2010s. In October 2019, the Cabinet announced that it would make some amendments to the Law on the Armed Forces on the expansion of military construction and engineering units of the Armed Forces into an independent military branch. In April 2020, the Minister of Defense, Nyamaagiin Enkhbold submitted a draft law on amendments to the Law on Armed Forces to the Speaker of the State Great Khural, providing for the creation of a "Civil Engineering Army" in the armed forces.
Units
339th Civil Engineering Unit (Bayankhongor Province)
014 Construction Unit
See also
United States Army Corps of Engineers
Russian Engineer Troops
Construction Troops (Bulgaria)
References
Military units and formations of Mongolia
Civil engineering organizations
Engineering units and formations
Military units and formations established in 2020
Construction in Asia
Construction organizations | Construction and Engineering Forces | [
"Engineering"
] | 579 | [
"Construction organizations",
"Civil engineering organizations",
"Engineering units and formations",
"Construction",
"Military engineering",
"Civil engineering"
] |
67,807,326 | https://en.wikipedia.org/wiki/The%20Heinz%20Sielmann%20Foundation | The Heinz Sielmann Foundation (de:Heinz Sielmann Stiftung) is a charitable organization based in Duderstadt, Germany. The organization has the official motto "Diversity is our nature" and it introduces people, especially children and young people, to a positive approach towards the nature through its programs involving interpersonal experiences. It also spreads public awareness about nature and its need for protection and carries out the preservation of the Heinz Sielmann archive of nature photographies/films.
History
The organization started its journey in 1996 at a property located at Herbigshagen, near the town of Eichsfeld, Duderstadt in Lower Saxony. It acquired the property in 2003. From the early days, the organizations imparts lessons to the school students in the State of Lower Saxony, working as the Regional Environmental Education Center. Its nature adventure house was reopened in 2019 where the exhibition "Diversity needs diversity" exhibited the visitors, the complex interrelationships of nature with the help of mosaic flaps and a media installation. A separate exhibition has been arranged under the title "Heinz Sielmann: A life in a film". The classics and awards of Heinz Sielmann are shown in a separate trophy room. On the northern part of the estate is the Franz von Assisi chapel, in which the urn of the foundation's founder Heinz Sielmann was buried in 2006 and his wife Inge in 2019.
Functions and activities
While working on charitable purposes, the foundation operates and supports a large number of biotope and animal sanctuary projects throughout Germany. It also acquires large landscapes in order to preserve them for nature conservation and to ensure the stability of biodiversity at the site. To protect nature and the environment, in particular to maintain the diversity of fauna and flora, the foundation also acts as a funding institution. It supports projects outside of government programs in Germany. Where the project subject is directly related to nature and environmental issues, the Foundation in individual cases also consider supporting projects outside Germany. The foundation confers four awards, namely Heinz Sielmann Honorary Prize, German Biodiversity Award, Heinz Sielmann Film Prize, and Heinz Sielmann Jugendfilmpreis, primarily to individuals who have taken extraordinary initiatives to protect biodiversity and ecological issues.
References
Biodiversity
Nature conservation organisations based in Germany | The Heinz Sielmann Foundation | [
"Biology"
] | 465 | [
"Biodiversity"
] |
67,808,182 | https://en.wikipedia.org/wiki/Treedom | Treedom is a platform that allows anyone to plant trees in different countries of the world. Treedom also allows the 'owner's of the planted trees to receive images of the trees that have just been planted along with its GPS coordinates and updates from the project it is part of.
Procedure
The project developer who applies to become a "tree planter" has to make a formal request in the form of the "project". The submission is reviewed to exclude projects that require cutting other trees to make the space, violate the law, consider planting invasive species and the like. The farmer confirms the fact of planting the tree with the help of the specialized mobile application that captures both photo and GPS coordinates. These reports are then manually checked, verifying the location, quality of the image and species of the planted tree. Trees that do not take root for the first three years must be replanted. Treedom claims inspecting in place at least 25% of these projects per year. Additionally, 5% of the planted trees are put aside as so called “Project Reserve” that should cover possible loss of trees and the related absorption (like trees that die after the third year, for which a substitution is not provided). A user can then order planting a selected tree online, paying as for a web purchase.
Tree planters
Treedom works in collaboration with small collective of farmers, local community and NGO across different countries including Kenya, Tanzania, Guatemala, Ecuador, Italy, Haiti, Nepal, Pakistan, Peru, Italy, etc.
For the trees which bear fruits, the fruits are reckoned to belong to the farmers who planted it. The farmer planting a tree remains responsible for its growth and take care where the organization provides support by arranging agroforestry training and income opportunities. The platform is known to promote welfare of farmers, including female farmers for which it announced 'Mothers day campaign' during March 2020 with the aim to spread awareness about the difficulties faced by female agricultural workers.
User interface
When a person chooses to own a certain tree, the sapling is planted by the local farmer on behalf of the person. The updates of the sapling are provided using GPS location and photographs on regular basis via webpage dedicated to this plant. Apart from this, the platform also allows a tree to be gifted. It is also possible to view the local weather data in the vicinity of the tree.
History
Treedom was founded in the year 2010 by Tommaso Speroni and Federico Garcea in Florence, Italy. The objective of the organization was described as The Sustainable Development Goals, which includes counter-deforestation, protecting biodiversity, preventing soil erosion, combating emission on one side and sustainable food production and income security for farmers on the other side. As in April 2021, Treedom has been reported to collaborate with 75000 farmers and plant more than 2 million trees across Asia, Africa and Central and South America.
Notes
Green computing e e-commerce sostenibile. Un piccolo viaggio negli impatti ambientali della rete,
Den Herzschlag der Natur spüren Achtsam und verbunden leben,
Energy Policy and Climate Change, ,
Subramanian Senthilkannan Muthu, Miguel Angel Gardetti, Sustainability in the Textile and Apparel Industries: Consumerism and Fashion Sustainability.
Zaigham Mahmood, Developing and Monitoring Smart Environments for Intelligent Cities,
References
Environmental organisations based in Italy
Biodiversity
Carbon emissions
Organizations established in 2010
B Lab-certified corporations | Treedom | [
"Biology"
] | 705 | [
"Biodiversity"
] |
67,809,195 | https://en.wikipedia.org/wiki/Fischer%20carbene | A Fischer carbene is a type of transition metal carbene complex, which is an organometallic compound containing a divalent organic ligand. In a Fischer carbene, the carbene ligand is a σ-donor π-acceptor ligand. Because π-backdonation from the metal centre is generally weak, the carbene carbon is electrophilic.
Fischer carbenes are named for Ernst Otto Fischer.
Structure
A metal carbene complex could be considered a Fischer carbene when the carbene is in singlet state. Delocalization of the lone pair from the substituent on carbene carbon raises the energy of pz orbital, thus forcing the two of electrons of carbene stay as an electron pair. Bonding between carbene and the metal centre involves a strong σ donation from sp2 orbital to an empty d orbital on metal centre and a weak π back donation from the metal centre to the empty pz orbital. Because the π donation is weak, the carbene carbon is electrophilic in nature.
Because of this bonding property, Fischer carbenes often feature:
low oxidation state metal center
middle and late transition metals Fe(0), Mo(0), Cr(0)
π-acceptor metal ligands
π-donor substituents on the carbene atom such as alkoxy and alkylated amino groups.
Preparation
The most common strategy to prepare a Fischer carbene is reaction between a metal carbonyl complex with organolithium compounds. The corresponding lithium enolate-like structure is highly stabilized, and thus, needs to be quenched by a highly electrophilic alkylating reagent such as Meerwein's salt. Alkylation with MeI could be done with a phase transfer system. Alternatively, the lithium cation could be exchanged with a tetraalkylammonium cation to give a more reactive enolate. This tetraalkylammonium salt could be acylated to give a highly electrophilic mixed anhydride-like Fischer carbene which could undergo nucleophilic substitution with alcohol.
Fischer carbenes with an α-hydrogen are prepared by reaction of a metal carbonyl anion with a formamide. Treating the intermediate with excess amount of trimethylsilyl chloride yields this particular group of Fischer carbene complex.
Elaboration of Fischer carbenes
With a suitable hydride abstracting reagent, such as the trityl cation, the hydride on alkyl ligand of a metal complex could be abstracted to form a Fischer carbene.
Decarbonylation from an unstabilized metal carbenoid
In 2021, Alvarez et al reported that a Fischer carbene could be effectively prepared from a decarbonylative process of a metal carbenoid derived from a stabilized diazo compound.
Reactivity
Carbonyl-like reactivity
The carbene carbon of a Fischer carbene is electrophilic in nature. Thus, Fischer carbenes exhibit similar reactivity compared to carbonyl compounds. Many of the reactions can be understood by using the carboxylic equivalent structure such as transesterification, Michael addition, and aldol reaction. The Cr(CO)5 moiety is a strong electron withdrawing group making the α-proton highly acidic. A methoxy chromium carbene with a methyl side chain has a pKa of 12.5 in aqueous acetonitrile (1:1 volume ratio). For comparison, methyl acetate has a pKa of 25.6, demonstrating the strong electron withdrawing nature of the Cr(CO)5 moiety.
The strong electron withdrawing nature of Fischer carbenes is also reflected in many reactions. For instance, the Diels–Alder reaction between methyl acrylate and isoprene is completed in 7 days at room temperature with low para-meta selectivity. On the other hand, the Fischer carbene counterpart finished in 3 hours at room temperature with much higher para-meta selectivity.
Urotropin, a weak nucleophile, could participate in a Michael addition to an alkynyl Fischer carbene, giving an interesting double addition product.
The enolate-like structure, obtaining by deprotonation of Fischer carbene, could be alkylated. However, because the carbanion is highly stabilized, a reactive alkylating reagent, such as methyl fluorosulfonate ("magic methyl" reagent) or methyl bromoacetate is needed.
Aldol condensation of Fischer carbenes could be achieved by using much weaker bases compared to its carbonyl counterpart, such as triethylamine.
Demetallation
Fischer carbenes could be oxidized to the corresponding carbonyl compounds using mild oxidants such as ceric ammonium nitrate (CAN).
If the side chain of Fischer carbene bears an α-proton, it could be reversibly deprotonated with a weak base such as pyridine. This facilitates formation of chromium hydride species, which can undergo reductive elimination to give a cis-enol ether.
Photochemical properties of Fischer carbenes
The UV-Vis spectrum of a Fischer carbene shows a metal-to-ligand charge transfer band in the near ultraviolet. On the one hand, this excitation promotes an electron from a metal centered orbital to a ligand centered orbital, making the carbene carbon more electron rich. On the other hand, the metal centre, already electron poor because of the carbonyl ligands, becomes more electron poor, facilitating migratory insertion to the CO ligand. This migratory insertion gives a chromium metallacyclopropanone, which is a resonance form of the metallated ketene. With ketene reactivity, the species could be trapped by several nucleophiles such as alcohols and amines, or could react in [2+2] cycloaddition with alkenes, imines, or aldehyde yielding the corresponding cyclobutane, β-lactam, and β-lactone adducts.
See also
Wulff–Dötz reaction
References
Carbenes
Organometallic compounds | Fischer carbene | [
"Chemistry"
] | 1,307 | [
"Inorganic compounds",
"Organometallic compounds",
"Organic compounds",
"Carbenes",
"Organometallic chemistry"
] |
67,812,278 | https://en.wikipedia.org/wiki/Diffblue | Diffblue Ltd is a spin-out from University of Oxford whose Cover product uses AI to automatically write unit tests for Java code. It is similar to GitHub Copilot in that it uses AI to write code, but differs in that it writes code fully autonomously vs. providing code suggestions for humans to review and edit. Diffblue was founded by Daniel Kroening and Peter Schrammel in 2016, and Mathew Lodge became CEO in July 2019
In 2017, Diffblue raised £17.3 million in Series A funding led by Goldman Sachs and Oxford Sciences Innovation. In 2020, Diffblue released a freeware version, Cover Community Edition. It can be used by both open source and commercial organisations. Diffblue raised $7m in January 2022 in a round led by venture capitalist IP Group, and a further $8m in November 2022 in a round led by AlbionVC.
Diffblue customers include Goldman Sachs, S&P Global, Citi, JP Morgan and AWS.
References
Software testing | Diffblue | [
"Engineering"
] | 219 | [
"Software engineering",
"Software testing"
] |
67,815,712 | https://en.wikipedia.org/wiki/Fermat%27s%20Last%20Tango | Fermat's Last Tango is a 2000 off-Broadway musical about the proof of Fermat's Last Theorem, written by husband and wife Joshua Rosenblum (music, lyrics) and Joanne Sydney Lessner (book, lyrics). The musical presents a fictionalized version of the real life story of Andrew Wiles, and has been praised for the accuracy of the mathematical content. The original production at the York Theatre received mixed reviews, but the musical was well received by mathematical audiences. A video of the original production has been distributed by the Clay Mathematics Institute and shown at several mathematical conferences and similar occasions. The musical has also been translated into Portuguese.
Synopsis
The plot is based on the story of the proof of Fermat's Last Theorem by Andrew Wiles, whose name is changed to "Daniel Keane" in the musical. After seven years of isolation in his attic, Keane believes he has found a proof of the theorem. The musical starts with a press conference, where Keane explains his proof to reporters and promises to return to normal life with his wife Anna and his family. After promising to Anna that he is now "done with Fermat", Keane is surprised in his study by none other than Fermat himself. Keane asks Fermat for the secret of his proof but is refused. Instead, Fermat introduces him to the "Aftermath", a "heavenly purgatory" where he meets the famous mathematicians Euclid, Pythagoras, Newton, and Gauss. They inform him that his proof contains a "big fat hole". In a second press conference, Keane is questioned by reporters about a flaw in the proof. Anna wishes for a corrected proof for her birthday. Fermat mocks Keane, and the other mathematicians inform him that "mathematics is a young man's game".
Keane returns to his attic to try to fix his proof, while his "math widow" wife is frustrated. Fermat continues to taunt Keane, but he is invisible and inaudible to Anna, and the three dance a "bizarre tango à trois" while Anna is confused by Keane talking to Fermat. The other mathematicians from the Aftermath, after noticing that they can't keep up with the mathematics of the past century, decide to grant admission to Keane even if he is unable to prove the theorem. As Keane finally gives up and declares his attempts a failure, Anna suggests that "within your failure lie the seeds of your success", repeating a line earlier spoken by the mathematicians. This quickly leads to Keane realising how to close the gap in the argument, and the musical ends with another press conference, and Fermat congratulates Keane for his proof.
Concept and writing
Rosenblum and Lessner started working on Fermat's Last Tango in December 1996, after Rosenblum had read a review of Amir Aczel's book Fermat's Last Theorem. Originally planned as an opera, it turned into a musical during the writing process, but operatic elements remained. The original working title had been Proof, but was later changed because of the successful 2000 play Proof. While written in a whimsical tone and using nerdy jokes, the lyrics contain sophisticated mathematical content and mention the Shimura-Taniyama conjecture. In the words of mathematician Arthur Jaffe, "the characters think about mathematics just the way a real mathematician would". Keane's mistake in his proof is an incorrect assumption about Galois representations, just as in the original proof attempt by Andrew Wiles. The number theorist Fernando Q. Gouvêa is credited as mathematics consultant for the musical; writer Lessner was not in contact with Wiles while the musical was created.
Almost the entire text is performed in song, with the exception of the prologue. The music contains elements of operetta, blues, pop, and tango. According to reviewer Simon Saltzman, the use of popular musical styles helps to make the show accessible despite its esoteric subject matter.
Original production
The original production by the York Theatre ran from November 21 to December 31, 2000 at the Theater at St. Peter's Lutheran Church, directed by Mel Marvin, with sets designed by James Morgan.
Cast:
Chris Thompson as Daniel Keane (baritone)
Jonathan Rabb as Pierre de Fermat (tenor)
Edwardyne Cowan as Anna Keane (mezzo-soprano)
Christianne Tisdale as Euclid and reporter 1 (soprano)
Carrie Wilshusen as Sir Isaac Newton and reporter 2 (mezzo-soprano)
Gilles Chiasson as Carl Friedrich Gauss and reporter 3
Mitchell Kantor as Pythagoras and reporter 4 (bass)
Musical numbers
The numbers are listed as in the CD production's liner notes.
Prologue – Reporter 4, Fermat
Press Conference I – Reporters, Keane
You're a Hero Now – Anna, Keane
The Beauty of Numbers – Keane
Tell Me Your Secret – Keane, Fermat
The Aftermath – Mathematicians, Fermat, Keane
I Dreamed – Keane, Anna
Press Conference II – Reporters, Keane, Anna
My Name – Fermat
All I Want for My Birthday – Anna
Game Show, Part I – Fermat, Keane
Young Man's Game – Fermat, Mathematicians
Game Show, Part II – Fermat, Keane, Mathematicians
Math Widow – Anna
I'll Always Be There (Fermat's Last Tango) – Fermat, Keane, Anna
Relay Race – Mathematicians
I'm Stumbling – Keane
Oh, It's You – Keane, Pythagoras
The Beauty of Numbers (reprise) – Anna, Keane
Press Conference III – Reporters, Keane, Fermat
Other performances
The musical was translated into Portuguese by César Viana as and was played in Portuguese university towns in 2003 and at the Teatro da Trindade in 2004. Students at Madison East High School performed an abridged version in 2005 and 2006, including at a statewide meeting of the Mathematical Association of America. In March 2023, the musical was performed at the University of Oxford in one of the Mathematical Institute's lecture halls.
Reception
Reviews for Fermat's Last Tango during its theatrical run were mixed. Wilburn Hampton's review in The New York Times, while noticing the catchy tunes and lyrics, found fault with Daniel Keane not "becom[ing] a real character". Elyse Sommer's review in CurtainUp was more positive, finding praise for both writing and the performances of Rabb and Thompson. Writing in the "Periodica" section of TotalTheater, reviewer Simon Saltzman praised Rabb and called the titular tango the highlight of the show.
The mathematical reception has been more generally positive, with audiences reactions to screenings of the film version ranging from "mildly amused to enthusiastic." Mathematician Robert Osserman, while acknowledging the musical as unique to the point of making comparisons difficult, found it fun and moving and praised the actors and the music. He especially pointed out the mathematical accuracy, but mildly complained about stereotyping of mathematicians and the differences between the true story of Andrew Wiles and the fictional story of Daniel Keane: Unlike Keane, Wiles did not withdraw to his attic for seven years and did not solve the complete Shimura-Taniyama conjecture. Richard Taylor's role in the proof is also omitted in the fictionalized version. Michele Emmer's review in the Mathematical Intelligencer was positive, stating "the gamble of trying to produce an entertaining and mathematically correct musical turned out a success." In their book Math Goes to the Movies, mathematicians Burkard Polster and Marty Ross were enthusiastic about Fermat's Last Tango, calling it "terrific fun" and a "must-see". In her book Science on Stage From Doctor Faustus to Copenhagen, literary scholar Kirsten Shepherd-Barr noted the musical's "successful integration of a surprising amount of 'real' mathematics with a charming and witty score."
In his book Dr. Riemann's Zeros: The Search for the $1 Million Solution to the Greatest Problem in Mathematics, journalist Karl Sabbagh wrote about seeing a performance of Fermat's Last Tango after meeting Andrew Wiles at Princeton. He described the Daniel Keane in the musical as "an accurate portrayal of Wiles" and stated "The writers of this musical had managed to capture the essence of the mathematical enterprise and to see that the human drama of Wiles's struggle with Fermat's Last Theorem embodied as much passion, frustration and triumph as is found in the plot of any conventional film or play." Andrew Wiles himself saw the musical in December 2000, with his family. In an interview, he later stated that he "really liked the portrayal of the personal part of the story - the whole idea of the threesome at the tango was beautifully done" and that he felt "it had been very intelligently written".
Recordings
On the initiative of Clay Mathematics Institute president Arthur Jaffe, a high quality live performance video was made, directed by David Stern. It was first shown to an audience of four hundred people in July 2001 in Berkeley, and later sold at cost by the Clay Mathematics Institute in both VHS and DVD editions. A pamphlet about the mathematics and the mathematicians as well as the actors in the musical was included. The film was shown at various mathematical conferences.
A recording made on December 18, 2000, was distributed as a CD version by Original Cast Records. It was positively reviewed by Matthew Murray, who especially praised Edwardyne Cowan's performance as Anna Keane.
References
Footnotes
Bibliography
External links
Off-Broadway musicals
2000 musicals
Sung-through musicals
Fermat's Last Theorem
Musicals inspired by real-life events | Fermat's Last Tango | [
"Mathematics"
] | 1,978 | [
"Theorems in number theory",
"Fermat's Last Theorem"
] |
67,816,296 | https://en.wikipedia.org/wiki/HD%201 | HD 1, also known as HIP 422, is the first star catalogued in the Henry Draper Catalogue. It is located in the northern circumpolar constellation Cepheus and has an apparent magnitude of 7.42, making it readily visible in binoculars, but not to the naked eye. The object is located relatively far away at a distance of 1,220 light years but is approaching the Solar System with a spectroscopic radial velocity of .
Characteristics
Originally thought to be a single object, observations from Griffin & McClure (2009) reveal it to be a single-lined spectroscopic binary. The components take approximately 6 years to circle each other in an eccentric orbit. The visible component is an evolved red giant branch (RGB) star with a stellar classification of G9-K0 IIIa, a spectral class intermediate between a G9 and K0 giant star. It has 3 times the mass of the Sun, but at the age of 350 million years it has expanded to 30 times its girth. It radiates 226 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of , giving it a yellowish-orange hue. HD 1A is metal enriched, with an iron abundance 74% above solar levels. The objects spins modestly with a projected rotational velocity of .
References
Spectroscopic binaries
1
000422
K-type giants
G-type giants
Cepheus (constellation)
BD+67 01599 | HD 1 | [
"Astronomy"
] | 298 | [
"Constellations",
"Cepheus (constellation)"
] |
67,816,840 | https://en.wikipedia.org/wiki/Mack%20Rides%20BigDipper | BigDipper is a type of steel roller coasters by Mack Rides. Being the first of its kind, the roller coaster Lost Gravity opened at Walibi Holland in March 2016.
Driving system
The trains run on steel rails. The short trains make it possible to drive through very tight curve radii. The roller coasters are basically driven by a chain lift hill, whereby the wagon after the lift covers the rest of the distance solely through gravity.
Trains
The trains consist of individual wagons with two rows each. In each row there are four seats next to each other, with the two inner seats placed above the rail and the outer two next to the rail. The outer seats are also slightly offset upwards. This means there is space for 8 people in one train.
Installations
References
External links
List of Installations on Roller Coaster Database
Roller coaster elements | Mack Rides BigDipper | [
"Technology"
] | 170 | [
"Roller coaster elements",
"Components"
] |
67,819,114 | https://en.wikipedia.org/wiki/R-16661 | R-16661 is an extremely toxic organophosphate insecticide. With an oral LD50 of 0.1 mg/kg in mice and rats, R-16661 is about 10 times more toxic than aldicarb, the most toxic carbamate insecticide.
See also
Aldicarb
Paraoxon
References
Organophosphate insecticides
Acetylcholinesterase inhibitors
Oxazolidines
Methyl esters
Phosphoramidothioates | R-16661 | [
"Chemistry"
] | 99 | [
"Phosphoramidothioates",
"Functional groups"
] |
67,819,316 | https://en.wikipedia.org/wiki/Tetramethylammonium%20perchlorate | Tetramethylammonium perchlorate is a perchlorate salt with a condensed formula [N(CH3)4]+ClO4−.
Preparation
Tetramethylammonium perchlorate can be produced by mixing cold, dilute perchloric acid with cold tetramethylammonium hydroxide, the reaction will lead to a white precipitation.
Uses
The perchlorate is used as an intermediate in organic synthesis, in chromatography and as a supporting electrolyte in electrochemistry. Along with trimethylammonium perchlorate, it was investigated as a component in composite propellants during the Cold War, but without much success.
References
Further reading
Hofmann, K. A.; Roth, R.; Hobold, K.; Metzler, A. Relationship between the Constitution and Behavior towards Water of Ammonium Oxonium Perchlorates. Berichte der Deutschen Chemischen Gesellschaft, 1911. 43: 2624-2630.
Perchlorates
Tetramethylammonium salts | Tetramethylammonium perchlorate | [
"Chemistry"
] | 218 | [
"Inorganic compounds",
"Perchlorates",
"Inorganic compound stubs",
"Salts"
] |
67,820,344 | https://en.wikipedia.org/wiki/NGC%203619 | NGC 3619 is an unbarred lenticular galaxy located in the constellation Ursa Major. It was discovered by the astronomer William Herschel on March 18, 1790.
NGC 3619 is part of a rich galaxy cluster. It also has a relatively large amount of gas.
References
External links
Ursa Major
3619
Unbarred lenticular galaxies
034641 | NGC 3619 | [
"Astronomy"
] | 74 | [
"Ursa Major",
"Constellations"
] |
67,820,384 | https://en.wikipedia.org/wiki/Generative%20Design%20in%20Minecraft | GDMC (short for Generative Design in Minecraft) is a programming competition to create procedurally generated settlements in Minecraft. The competition is organized by academics from New York University, the University of Hertfordshire and the Queen Mary University of London.
Organisers
Michael Cerny Green (New York University)
Christoph Salge (University of Hertfordshire)
Rodrigo Canaan (New York University)
Christian Guckelsberger (Queen Mary University of London)
Julian Togelius (New York University)
References
External links
Official Wiki
Programming contests
Recurring events established in 2018 | Generative Design in Minecraft | [
"Technology"
] | 114 | [
"Computing stubs"
] |
67,821,139 | https://en.wikipedia.org/wiki/Invasive%20species%20in%20the%20Philippines | The following is a list of invasive alien species (IAS) in the Philippines. These species are regarded to have a negative effect on the local ecosystem and the economy, although not all species introduced from outside the archipelago are considered as "invasive".
Notable species
Animals
Plants
References
Philippines
Philippines
Biota of the Philippines
Agriculture in the Philippines
Environmental issues in the Philippines | Invasive species in the Philippines | [
"Biology"
] | 73 | [
"Biota by country",
"Biota of the Philippines"
] |
67,821,446 | https://en.wikipedia.org/wiki/Charles%20Sidney%20Bluemel | Charles Sidney Bluemel (17 July 1884 – 17 December 1960) was a British–American psychiatrist and pioneer of speech pathology, best known for his research on stuttering. He had a stammer himself, which influenced his lifelong pursuit of understanding the speech disorder and discovering a cure.
Bluemel was born in London. After graduating from boarding school in Margate, he spent a year in Germany before apprenticing at bicycle company Bluemel Brothers for three years. He emigrated to the United States and studied at University of Colorado where he obtained his M.D. in 1916. He practiced psychiatry in Denver and was the owner of Mount Airy Sanitarium (1927–1953), a private psychiatric hospital.
Bluemel was a major influence on the theories and therapies of stuttering. His research from his career during 1913–1960 influenced stuttering theory. For example, he developed the theory of primary and secondary stuttering in 1913. He also documented the historical treatment of the subject as far back as ancient Greece and Rome.
Bluemel was editor of Colorado Medicine (1924–1925) and Denver Medical Bulletin (1920–1921). He married Elinor Hensley in 1921, they had two children.
He was a Fellow of the American College of Physicians, American Psychiatric Association and the American Association for the Advancement of Science. He was a Licentiate of the Royal College of Physicians of London and Royal College of Surgeons of England.
Bluemel was an activist for vivisection. In 1922, he authored The Heart of the Anti-Vivisectionist which criticized arguments of the anti-vivisection movement. In 1940, he donated his library on stuttering to the University of Denver. In 1960, Bluemel was awarded the Honors of the American Speech and Hearing Association.
Selected publications
Stammering and Cognate Defects of Speech (1913)
Stammering: A Bibliography of the Past Decade, 1911 to 1920 (1921)
The Heart of the Anti-Vivisectionist (1922)
Mental Aspects of Stammering (1930)
Stammering: A Bibliography (1931)
Stammering and Allied Disorders (1935)
The Troubled Mind (1938)
War, Politics and Insanity (1948)
Psychiatry and Common Sense (1954)
The Riddle of Stuttering (1957)
References
1884 births
1960 deaths
American psychiatrists
English emigrants to the United States
Speech and language pathologists
Vivisection activists
20th-century American physicians
20th-century British medical doctors
Fellows of the American College of Physicians
Fellows of the American Association for the Advancement of Science
University of Colorado School of Medicine alumni
Stuttering
Physicians from Colorado
People from Denver
Heads of psychiatric hospitals
British psychiatrists
People with speech disorders | Charles Sidney Bluemel | [
"Chemistry"
] | 541 | [
"Vivisection activists",
"Vivisection"
] |
67,822,715 | https://en.wikipedia.org/wiki/National%20Streaming%20Day | National Streaming Day is an unofficial holiday occurring on May 20, intended to celebrate streaming media. It was established in 2014 by Roku. In recent years, some streaming services have used the holiday to offer streaming promotions or discounted products.
Origins
National Streaming Day was started by the streaming platform Roku, initially to celebrate the anniversary of their first streaming device launch, The Netflix Player, on May 20, 2008. The first holiday was celebrated on May 20, 2014. It began as a celebration of streaming, with users of streaming platforms "encouraged to stream at least 60 minutes of their favorite entertainment today and share their selection using hashtag."
More recently, the holiday began to see streaming services make announcements of upcoming content and/or releases. Roku often offers discounts on their devices, such as Roku Streaming Stick+ and Roku Ultra. They also offered free access to normally exclusive content that would require payment or subscription. This was following a partnership with Showtime to offer some of their exclusive content for free on May 20.
On National Streaming Day 2020, Disney+, ESPN+ and Roku announced a collaboration to release exclusive news and series sneak peeks.
Announcements
On National Streaming Day 2020, Disney announced the release of Muppets Now, an unscripted Muppets show to air on Disney+. It also used the unofficial holiday to announce a monthly bundle deal where the three streaming services were available for $12.99 a month. Disney used May 20, 2020, to also announce the release of new content, the film Artemis Fowl. During the same year, ESPN used National Streaming Day to announce the return of Peyton's Places for a second season.
In 2021, Roku announced the release of their new Roku Originals on National Streaming Day.
References
Streaming television
May observances
Unofficial observances
Recurring events established in 2014 | National Streaming Day | [
"Technology"
] | 375 | [
"Multimedia",
"Streaming television"
] |
67,822,906 | https://en.wikipedia.org/wiki/MadamePee | madamePee is a mobile female urinal, without contact and without water supply. It is designed to be used at public events such as concerts or music festivals, but also in more durable situations such as construction sites, public gardens, etc.
Context
Female urination in public events is an ongoing issue (see section History in female urinal): differences in needs, conventions and practices translate into a blatant inequality of access between men and women, with longer queues and waiting times for women. Since the beginning of the 20th century, many initiatives have been taken (see female urinal devices) to deal with this problem: including portable individual urinals, men-like urinals but adapted to the women morphology, unisex urinals, specific cabin urinals etc. However, who has attended outdoor rock concerts can attest that no standard and durable solution has been found and adopted.
Rationales
Studies have shown that the separation of urination and defecation devices, such as for men, increases the efficiency of women's toilets, in terms of space optimization and service duration; for event planners, this means more devices, used more efficiently, with constant resources.
Implementation in public of female urinals has psychological and social implications, which strongly depend on the cultural environment. The degree of intimacy preservation is an important issue, viewed differently in unisex toilets or in cabin toilets.
Concept
Nathalie des Isnards was so upset to miss the show of her favorite rock group, because of the time spent to access the toilets, that she contacted several designers, installation providers and psychologists to find an industrial solution. Building on the previous experiences, such as the contactless urination devices, madamePee is based on the following premises:
Mobility: devices should be easily installed and uninstalled;
Environmental sustainability: no need for water supply (which adds to the mobility above) and urine collection for fertilizer uses;
Privacy: to meet the needs of various countries and contexts, light cabins with hinged doors, possibly with a veil as roof.
Several patents have been taken, for example for the urinal itself which must not retain bad smells after use.
madamePee cabins have been installed in major public events for several years (e.g. Hellfest, Parisplages, Solidays...) ; they are distributed by major rental companies of mobile sanitary facilities. They are now installed in countries outside France: Portugal, Belgium, Andorra, Ivory Coast, Canada.
In 2022, Nathalie des Isnards was recognized as "Woman entrepreneur of the year, favorite of the jury" at the "Women in Industry" trophies (Paris 2022) awarded by the magazine "l'Usine Nouvelle".
Developments
The COVID-19 pandemic halted the holding of outdoor festivals worldwide in the years 2019–2020, they were the first outlet for Madame Pee female urinals. Since the end of 2021, again, festivals have been organized bringing together hundreds of thousands of participants; MadamePee urinals were present at major events such as HellFest2022 (420,000 tickets sold) or Solidays in Paris.
The pandemic with restrictions on access to cafes and bistros has highlighted the need for public toilets for women in cities. Large cities in Western Europe are concerned with installing toilets in public places that are easy to maintain, without a water connection; about ten cities in France are experimenting with MadamePee urinals permanently installed in urban areas.
Climate change results in extreme drought in Western Europe in 2022, after several unusually dry summers; the use of drinking water in toilets is increasingly questioned and becomes a determining factor in the development of dry toilets (without connection to the drinking water network).
Finally, human urine as fertilizer is an alternative to the use of chemical fertilizers. Urine collection is not possible in general purpose toilets; madamePee type urinals provide pure urine which is collected and transformed.
A version for men has been developed (misterPee 2022) based on the same characteristics as the madamePee urinals: no contact, no water, no need for connection to the sewer.
In 2022, a European standard on "mobile non-sewer-connected toilet cabins" has been adopted and published in 2023 by AFNOR. It states the requirements of services and products relating to the deployment of cabins and sanitary products and applies to madamePee's products.
See also
Female urinals
Female urination device
Public toilets
Nathalie_des_Isnards (in French)
Pollee
References
Toilets
Sanitation
Urinals
Feminine hygiene | MadamePee | [
"Biology"
] | 937 | [
"Excretion",
"Toilets"
] |
67,823,169 | https://en.wikipedia.org/wiki/History%20Chip | History Chip is a website dedicated to recreating history as a mosaic of individual recounts.
History
Story Chip was founded in 2009 by Jean Pamela McGavin and her brother Lee McGavin and later renamed History Chip. It is an archive of non-fiction, personal narratives for the expansion of contemporary history by including stories and experiences of all members of society. Its current director is Jean McGavin. History Chip was awarded the 2021 Connecticut Entrepreneur Award for Community Favorite Venture Pre-Revenue.
Themes
All people are invited to share stories on a broad framework. Stories on any topic are accepted for inclusion into the database, describing for example events, societal norms, food, clothing, nature, military, government, etc. Topics are not limited by any in particular and have a broad scope and wide perspective. The editors reserve the right to exclude stories based on hate speech, pornography, and blatant falsehoods. Outreach is expansive in order to include global storytellers and historically underrepresented communities - women, economically disadvantaged, native peoples, people in developing countries, LGBTQ, and people of color.
Mission and scope
History Chip's mission is to present all sides of history. It was in part, a response to teaching materials used in the 1950s and 1960s in Virginia. The Virginia State history textbook, Virginia: History • Government • Geography, taught that slaves' lives were better on the plantations and that they were happier than they would have been in Africa. Virginia children were taught that the day the first slaves were brought to Virginia was a day to celebrate. "Virginia offered a better life for the Negroes than did Africa. In his new home, the Negro was far away from the spears and war clubs of enemy tribes. He had some of the comforts of civilized life. He had better food, a better house, and better medical care than he did in Africa. And he was comforted by a religion of love and mercy."
Slave narratives and African American points of view were apparently absent from that and many other textbooks. African American perspectives would have offered a more complete and honest historical presentation of life in Virginia. The absence of their story challenges the foundation of all history taught in Virginia at that time. For Virginia history to be truthful, points of view of the significant parties, on significant issues, such as slavery, are imperative.
As textbooks bear the weight of authority, teaching from a textbook renders the information in that textbook as fact when presented to young children. Teaching young children that slavery was a good thing for Africans kidnapped and taken to the Americas (an assumption that would not likely have reflected truthfully in the minds of African Americans), runs the risk of solidifying that notion in the minds of large numbers of children who may maintain those falsehoods into adulthood, running the risk of institutionalizing racism and conflict.
In an effort to counter the sort of history taught with only limited perspectives, as was the case in the Virginia textbook, History Chip was established to include voices from all walks of life, thus expanding historical perspectives and understanding. In an effort to effort to stay true to the voices of everyday voices, people's stories are not edited rather published as submitted.
The website contains approximately 500 articles from 70 different authors.
Name change
The project and website were renamed in 2019 as History Chip, for branding reasons.
See also
A People's History of the United States
Lies My Teacher Told Me
Further reading
References
Notes
A.See Simkins et al., p.187
Tertiary educational websites
Digital humanities | History Chip | [
"Technology"
] | 712 | [
"Digital humanities",
"Computing and society"
] |
63,498,084 | https://en.wikipedia.org/wiki/Heinrich%20M%C3%BCckter | Heinrich Mückter (14 June 1914 – 22 May 1987) was a German medical doctor, pharmacologist and chemist.
World War II
During the Nazi occupation of Poland, Mückter was deputy director of the Kraków Institute for Typhus and Virus Research. Mückter and his colleagues repeatedly experimented on concentration camp prisoners in Buchenwald. Many prisoners died as a result of the experiments.
Accused by Polish war crimes prosecutors of conducting medical experiments on concentration camp prisoners and Nazi forced labourers, Mückter escaped arrest and fled back to Germany.
Invention of thalidomide
In 1946 Mückter became Head of Research at the Grünenthal pharmaceutical company, where he further developed the infamous drug thalidomide which had been synthesized in 1952 by Chemical Industry Basel. Aggressively-marketed as an over-the-counter sleeping pill and remedy for morning sickness in pregnancy, thalidomide was first made available on 1 October 1957, and it became the second best-selling medication in Germany after Bayer Aspirin. Thalidomide was eventually found to cause miscarriages, severe birth defects in babies whose mothers had taken the medication while pregnant, and severe nerve damage.
In January 1968, Mückter was put on trial along with other Grünenthal employees. The trial ended abruptly in April 1970 with a settlement.
Mückter was never charged in relation to his role in experiments on concentration camp prisoners, nor his role in the thalidomide scandal. He died on 22 May 1987.
References
1914 births
1987 deaths
German pharmacologists
20th-century German chemists | Heinrich Mückter | [
"Chemistry"
] | 323 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
63,498,181 | https://en.wikipedia.org/wiki/Adawro%20exclosure | Adawro is an exclosure located in the Dogu'a Tembien woreda of the Tigray Region in Ethiopia. The area has been protected by the local community since 1994.
Environmental characteristics
Average slope gradient: 70%
Aspect: the exclosure is oriented towards the northeast
Minimum altitude: 2635 metres
Maximum altitude: 2705 metres
Lithology: Basalt
Management
As a general rule, cattle ranging and wood harvesting are not allowed. The grasses are harvested once yearly and taken to the homesteads of the village to feed livestock. Physical soil and water conservation has been implemented to enhance infiltration, and vegetation growth.
Benefits for the community
Setting aside such areas fits with the long-term vision of the communities were hiza’iti lands are set aside for use by the future generations. It has also direct benefits for the community:
improved infiltration
improved ground water availability
honey production
climate ameliorator (temperature, moisture)
carbon sequestration, dominantly sequestered in the soil, and additionally in the woody vegetation)
Water conservation
In the Adawro exclosure, more than 800 precise measurements were done in 2003 and 2004, using five runoff plots, where the volume of runoff was measured daily. The rock type (basalt), slope gradient and slope aspect were the same, the only difference was the land management and vegetation density. Whereas in degraded rangeland, 11.4% of the rainfall flows directly away to the river (runoff coefficient), this happens only for 2.5% of the rain in a recent exclosure and 3.2% in a eucalyptus forest.
In 2003, the soils of the then young exclosure could hold 280 litres of water per m³, similar to the adjacent rangeland.
Improved ecosystem
With vegetation growth, biodiversity in this exclosure has strongly improved: there is more varied vegetation and wildlife.
Trees
The main tree species found in the exclosure are:
Flat top acacia (Acacia abyssinica, renamed as Vachellia abyssinica)
Golden wattle (Acacia saligna)
Rumex nervosus, a woody sorrel species
Aloe macrocarpa
Soils
Main soil type in the exclosure are Phaeozems, formed in sediment that has been trapped by the vegetation of the exclosure, and as a remnant of the original situation before deforestation. Remarkably, also in the well-protected eucalypt plantation there is some undergrowth and soil development.
References
External links
Link For Forestry Projects
Exclosures of Tigray Region
1999 establishments in Ethiopia
Land management
Environmental conservation
Environmentalism in Ethiopia
Emissions reduction
Dogu'a Tembien | Adawro exclosure | [
"Chemistry"
] | 551 | [
"Greenhouse gases",
"Emissions reduction"
] |
63,498,198 | https://en.wikipedia.org/wiki/Khunale%20exclosure | Khunale is an exclosure located in the Dogu'a Tembien woreda of the Tigray Region in Ethiopia. The area has been protected since 1990 by the local community.
Environmental characteristics
Source:
Aspect: the exclosure is oriented towards the northwest
Minimum altitude: 2420 metres
Maximum altitude: 2480 metres
Lithology: mixed sandstone and limestone lithology, partly covered by transported vertic clay material
Management
As a general rule, cattle ranging and wood harvesting are not allowed. The grasses are harvested once yearly and taken to the homesteads of the village to feed livestock. Physical soil and water conservation has been implemented to enhance infiltration, and vegetation growth.
Benefits for the community
Setting aside such areas fits with the long-term vision of the communities were hiza’iti lands are set aside for use by the future generations. It has also direct benefits for the community:
improved infiltration
improved ground water availability
honey production
climate ameliorator (temperature, moisture)
carbon sequestration, dominantly sequestered in the soil, and additionally in the woody vegetation)
Water conservation
In the Khunale exclosure, more than 600 precise measurements were done in 2003 and 2004, using seven runoff plots, where the volume of runoff was measured daily. The rock type (Amba Aradam Sandstone and Antalo Limestone), slope gradient and slope aspect were the same, the only difference was the land management and vegetation density. Whereas in degraded rangeland, 11.8% of the rainfall flows directly away to the river (runoff coefficient), this happens only for 4.7% of the rain in a recent exclosure and 0.3% in an old exclosure.
Improved ecosystem
With vegetation growth, biodiversity in this exclosure has strongly improved: there is more varied vegetation and wildlife.
In the oldest parts of this exclosure, humus profiles are best developed. The old exclosures are also characterised by a variety of humus forms, caused by the variation in shrub and tree density and species composition.
References
External links
Link For Forestry Projects
1990 establishments in Ethiopia
Land management
Environmental conservation
Emissions reduction
Exclosures of Tigray Region
Dogu'a Tembien | Khunale exclosure | [
"Chemistry"
] | 462 | [
"Greenhouse gases",
"Emissions reduction"
] |
63,498,200 | https://en.wikipedia.org/wiki/List%20of%20World%27s%20Fair%20architecture | This is a list of buildings and structures built for World's Fairs.
Officially recognized exhibitions
Architecture built for world's fairs recognized by the Bureau International des Expositions.
London Great Exhibition 1851
The Crystal Palace
Paris Exposition Universelle 1855
Palais de l'Industrie
Théâtre du Rond-Point
London International Exhibition 1862
The Exhibition Building of 1862
Paris Exposition Universelle 1867
Palais du Champ de Mars
Vienna World's Fair 1873
Rotunda
Philadelphia Centennial Exposition 1876
Main Exhibition Building
Paris Exposition Universelle 1878
Palais du Trocadéro
Melbourne International Exhibition 1880
Royal Exhibition Building
Barcelona Universal Exposition 1888
Parc de la Ciutadella
Paris Exposition Universelle 1889
Eiffel Tower
Galerie des machines
Chicago World's Columbian Exposition 1893
White City
Brussels International Exposition 1897
Palace of the Colonies
Paris Exposition Universelle 1900
Grand Palais
Petit Palais
Liège International 1905
Palais des beaux-arts de Liège
San Francisco Panama–Pacific International Exposition 1915
Tower of Jewels
Palace of Fine Arts
Barcelona International Exposition 1929
Palau Nacional
Barcelona Pavilion
Estadi Olímpic Lluís Companys
Poble Espanyol
Teatre Grec
Magic Fountain of Montjuïc
Paris Exposition Internationale des Arts et Techniques dans la Vie Moderne 1937
Palais de Chaillot
New York World's Fair 1939
1939 New York World's Fair pavilions and attractions
Trylon and Perisphere
Brussels Expo 58
Atomium
Philips Pavilion
Seattle Century 21 Exposition 1962
Seattle Center
Seattle Center Monorail
Space Needle
Montreal Expo 67
Expo 67 pavilions
Habitat 67
San Antonio HemisFair '68
Tower of the Americas
Others
Porto International Exhibition 1867
Palácio de Cristal
Sydney International Exhibition 1879
Garden Palace
Adelaide Jubilee International Exhibition 1887
Jubilee Exhibition Building
Hanoi Exhibition 1902
Grand Palais
Colonial Exhibition of Semarang 1914
Aceh Museum
Paris Colonial Exposition 1931
Palais de la Porte Dorée
Pagode de Vincennes
Glasgow Empire Exhibition 1938
Tait Tower
New York World's Fair 1964
1964 New York World's Fair pavilions
New York City Pavilion
New York Hall of Science
New York State Pavilion
Terrace on the Park
Wisconsin Pavilion
Unisphere
References
Architecture
World's Fair
Architecture | List of World's Fair architecture | [
"Engineering"
] | 415 | [
"Architecture lists",
"Architecture"
] |
63,498,286 | https://en.wikipedia.org/wiki/Calconcarboxylic%20acid | Calconcarboxylic acid (IUPAC name 3-hydroxy-4-[(2-hydroxy-4-sulfonaphthalen-1-yl)diazenyl]naphthalene-2-carboxylic acid; commonly called Patton and Reeder's Indicator) is an azo dye that is used as an indicator for complexometric titrations of calcium with ethylenediaminetetraacetic acid (EDTA) in the presence of magnesium. Structurally, it is similar to eriochrome blue black R, which is obtained from calconcarboxylic acid by decarboxylation and reaction with sodium hydroxide.
Properties
Calconcarboxlic acid is soluble in water and a variety of other solvents, including sodium hydroxide, ethanol and methanol. It has a violet colour in dissolved form in ethanol. The melting point of calconcarboxylic acid is at approximately 300 °C, where it undergoes thermal decomposition.
Background
Though the determination of calcium and magnesium by complexometric titration with standard solutions of disodium dihydrogen tetraacetate, utilising Eriochrome Black T as indicator is widely accepted and quite adequately understood, it, like other complexometric titration methods, suffers from the limitations of having an indistinct endpoint (where a photometric titrator is needed to provide acceptable accuracy) and/or having to separate the metals before titration can occur. Calconcarboxylic acid was thus adopted as a superior alternative due to its ability to give a good and visual endpoint and its rapid performance even with the presence of magnesium.
Synthesis
As described by James Patton and Wendell Reeder in 1956, calconcarboxylic acid can be synthesised by coupling diazotized 1-amino-2-naphthol-4-sulfonic acid with 2-hydroxy-3-napthoic acid.
Applications
Calconcarboxylic acid is used for the determination of calcium ion concentration by complexometric titration. Free calconcarboxylic acid is blue colour, but changes to pink/red when it forms a complex with calcium ions. EDTA forms a more stable complex with calcium than calconcarboxylic acid does, so addition of EDTA to the Ca–calconcarboxylic acid complex causes formation of Ca-EDTA instead, leading to reversion to the blue colour of free calconcarboxylic acid.
For the complexometric titration, the indicator is first added to the titrant containing the calcium ions to form the calcium ion-indicator complex (Ca-PR) with a pink/red colour. This is then titrated against a standard solution of EDTA. The endpoint can be observed when the indicator produces a sharp, stable colour change from wine red to pure blue, which occurs at pH values between 12 and 14, this indicates the endpoint of the titration, as the Ca-PR complexes have been completely replaced by the Ca-EDTA complexes and hence the PR indicator reverts to its blue colour.
The reaction can be given by:
Ca-PR + EDTA4- → PR + [Ca-EDTA]2-
The Patton-Reeder Indicator is often used here in the form of a triturate.
This method of complexometric titration is dependent on the pH of the solution being sufficiently high to ensure that magnesium ions precipitate as magnesium hydroxide before the PR indicator is added to prevent interference with the results, as if magnesium were present, the EDTA would also form complexes with it. Concentrated sodium hydroxide or potassium hydroxide is usually added to the solution to this end.
The accuracy of this method may also be affected by the presence of metal ions such as copper, iron, cobalt, zinc or manganese in sufficiently high concentrations.
References
Azo dyes
Chemistry
Carboxylic acids
Sulfonic acids | Calconcarboxylic acid | [
"Chemistry"
] | 823 | [
"Carboxylic acids",
"Functional groups",
"Sulfonic acids"
] |
63,498,700 | https://en.wikipedia.org/wiki/NGC%20821 | NGC 821 is an elliptical galaxy in the constellation Aries. It is estimated to be about 80 million light-years from the Milky Way and has a diameter of approximately 55,000 light years. NGC 821 was discovered on September 4, 1786, by astronomer Wilhelm Herschel.
See also
List of NGC objects (1–1000)
References
External links
Elliptical galaxies
Aries (constellation)
0821
008160 | NGC 821 | [
"Astronomy"
] | 86 | [
"Aries (constellation)",
"Constellations"
] |
63,498,746 | https://en.wikipedia.org/wiki/NGC%20822 | NGC 822 is an elliptical galaxy in the constellation Phoenix. It is estimated to be about 233 million light-years from the Milky Way and has a diameter of approximately 80,000 light-years. NGC 822 was discovered on September 5, 1834, by astronomer John Herschel.
See also
List of NGC objects (1–1000)
References
Phoenix (constellation)
0822
Elliptical galaxies
008055 | NGC 822 | [
"Astronomy"
] | 82 | [
"Phoenix (constellation)",
"Constellations"
] |
63,498,941 | https://en.wikipedia.org/wiki/North-methanocarbathymidine | North-Methanocarbathymidine (N-MCT) is an antiviral drug which is an analogue of thymidine, and shows activity against herpesviruses, orthopoxviruses and HIV, though it has not been introduced into clinical use.
References
Antiviral drugs | North-methanocarbathymidine | [
"Biology"
] | 65 | [
"Antiviral drugs",
"Biocides"
] |
63,499,035 | https://en.wikipedia.org/wiki/Ella%20Pilcher | Ella Sophia Gertrude Pilcher (/4 - 19 May 1939) was a British pioneer aviator, and the first woman to fly in a glider in the British Isles. She co-created and flew in gliders designed by Percy Pilcher, her younger brother, in the 1890s and is considered to be the first woman who sewed wings. She was made an honorary member of the Royal Aeronautical Society in December 1899.
Early life
Ella Pilcher was born in Harrow to a Scottish mother, Sophia (née Robinson), and Somerset-born father, Thomas Webb Pilcher. Her father was on his second marriage, having had a previous life as curator of a British gallery in Rome and husband of an Italian marchioness. He was in his sixties for most of his children's births and died in 1874. Sophia took Ella and her siblings Thomas, Ada Violet and Percy to Germany but then herself died only three years later. The orphans returned to England, the charges of the eldest brother Thomas Pilcher, who at 19 joined the army to pay for the schooling of his sisters. Percy was enrolled as a naval cadet at the age of 13 and upon graduation pursued an apprenticeship in the engineering department of a Glasgow shipyard. Ella went with Percy to Glasgow as his companion and housekeeper, while Ada Violet stayed south with Thomas.
Ella and Percy lived in a flat in Byres Road, Glasgow, and were remembered by friends as bright, clever and attractive. Ella was, according to friends and family, a great singer.
Gliding
Ella supported her brother's passionate interest in aeronautics which, she remembered, he had had since childhood. At Byres Road they kept birds in order to observe them in flight and landing. Percy followed the experiments of German pioneer glider Otto Lilienthal closely, and made scale models of gliders which he would fly around the apartment. In early 1895 the siblings decided to make a full sized prototype of what they called a 'soaring machine'. Percy did the design, carpentry and tensioning. Ella was in charge of the fabric. They moved house to Kersland Street, Glasgow (the landlady at Byres Road objected to the birds and the models), and began constructing the aircraft in five sections. They used the best materials they could get with their limited funds: pine, sailcloth, steel plates, piano wire and bamboo. It was difficult to lay out the fabric in order to cut and sew it at home, and they were lent a room at Glasgow University by its principal, the physicist Lord Kelvin, despite his friendly scepticism towards aeronautical progress. Ella was helped by Iris Biles, the daughter of the professor Percy assisted.
They called this first glider the Bat, and began test flying it at Cardross, farmland to the west of Glasgow, in the summer of 1895. By September of that year, taking advantage of the long university vacation, Ella and Percy had modified the Bat to the point where it would carry one of them aloft for 30 seconds, double that if towed by a rope. Percy did most of the test flying, but Ella took at least one tethered flight. They also worked on two other models, which did not turn out so well: the Beetle and the Gull. For the Gull, Ella managed to sew 300 square feet of sailcloth into the wings specified by Percy in less than a month.
Ella Pilcher appears with Percy and the gliders in over half of the photographs dating from 1895–6, which the siblings must have commissioned in order to send to the press. By the spring of 1896, the Pilchers had featured in a number of publications in Britain, the United States and Germany, though only Percy was ever mentioned by name. They were working on a new model, the Hawk, which would remain their highest achievement in aeronautics.
She moved down to London when Percy was invited to join American-born arms magnate and aeronautical pioneer Hiram Maxim as his assistant in April 1896. Percy was given space at Maxim's flight test site at Eynsford in Kent to house and trial the Hawk. Ella helped Percy organise a demonstration of the Hawk on Sunday 20 June 1897 - Percy was hoping to find an investor to support him in developing and installing a motor in the glider. She oversaw the installation and operation of a rope pulley across the valley from Percy's launch site, and was instrumental in the success of the day, in which Percy achieved impressive tethered and free flights. One of the scientists who attended, phonograph enthusiast and fellow of the Meteorological Society Douglas Archibald, mentioned Ella in his account:I hope I may be permitted to remark that Mr. Pilcher has been, fortunately, blessed with the possession of a sister, who not only acted as the presiding goddess of the tea-table on the present occasion, but actually made most of the wing surfaces with her own hands.The demonstration also saw a (possibly unplanned) flight by Dorothy Rose Pilcher, Ella's cousin, who was given a tow by Percy but then crashed into the cinematograph camera which had been set up to take stills of the glider in flight. Neither the aviator nor the apparatus was damaged.
While it did not yield an investor, the demonstration was impressive enough for Percy to start up a company with a colleague, Walter Gordon Wilson. At this point Ella probably stepped back from her role as Percy's collaborator, and may have begun training as a nurse. Nonetheless, she still accompanied Percy on his most important trial flights, and helped him prepare for lectures.
In the late summer of 1899 another demonstration was planned, at Stanford Hall in Leicestershire, for the benefit of prospective investor John Henniker Heaton and a few others. Despite bad weather, Percy insisted on making a flight in the Hawk and suffered an accident. He died from his injuries three days later, Ella at his side. Within a month Ella had embarked for Cape Town to serve as a nurse in the Second Boer War.
Just weeks after Percy's death, Ella wrote to Robert Baden Powell, who had been a supporter of the Pilchers' gliding experiments and was de facto president of the Aeronautical Society of Great Britain (which was later renamed the Royal Aeronautical Society), requesting membership on her own behalf. "I should not like our name to be taken off your lists. As I always helped my dear brother in his experiments, I am able to take great interest in the subject." Five weeks later, she was voted an honorary member.
Later life
Ella married Colonel Edward C. Tidswell in the autumn of 1902, and accompanied him on his stationing in Kumasi, now Ghana.
She donated Percy's models, sketches and photographs to the Royal Aeronautical Society that year, and went on to contribute an article about him to the Aeronautical Journal in 1909. Over a decade later she corresponded with the society again in order to offer more material and information about Percy, whose legacy she feared was being forgotten
On her husband's retirement from military service, the couple moved to Jersey, where they lived at St Brelade's Bay. According to her niece, Ella was still running down hills in her seventies, teaching her great nephew to fly a kite, months before she died in 1939.
References
1860s births
1939 deaths
Aeronautical engineers
British aviation pioneers
English glider pilots
British women aviators
British nurses
Royal Aeronautical Society | Ella Pilcher | [
"Engineering"
] | 1,501 | [
"Aerospace engineering organizations",
"Royal Aeronautical Society"
] |
63,499,308 | https://en.wikipedia.org/wiki/C12-15%20pareth-12 | C12-15 pareth-12 (INCI name) is an emulsifier and surfactant commonly used in cosmetics formulations. It is a polyethylene glycol ether formed by combining synthetic C12–C15 fatty alcohols with 12 moles of ethylene oxide.
According to the INCI, "the term Pareth applies to ethoxylated paraffinic alcohols containing both even- and odd-carbon chain length fractions."
References
Cosmetics chemicals
Ethers
Surfactants | C12-15 pareth-12 | [
"Chemistry"
] | 108 | [
"Organic compounds",
"Functional groups",
"Ethers"
] |
63,499,323 | https://en.wikipedia.org/wiki/NGC%20823 | NGC 823, also known as IC 1782, is an unbarred lenticular galaxy in the constellation Fornax. It is estimated to be 194 million light-years from the Milky Way and has a diameter of approximately 100,000 light years. NGC 823 was discovered on October 14, 1830, by astronomer John Herschel.
SN 2022abid (ZTF22abyelas) a Type Ia supernova from an exploding white dwarf was discovered on 23 November 2022.
See also
List of NGC objects (1–1000)
References
Unbarred lenticular galaxies
Fornax
0823
IC objects
008093 | NGC 823 | [
"Astronomy"
] | 131 | [
"Fornax",
"Constellations"
] |
63,499,689 | https://en.wikipedia.org/wiki/ISO/IEC%2027018 | ISO/IEC 27018 Information technology — Security techniques — Code of practice for protection of personally identifiable information (PII) in public clouds acting as PII processors is a privacy standard, part of the ISO/IEC 27000 family of standards. It was among the first international standards about privacy in cloud computing services. It is based on ISO/IEC 27002. It helps cloud service providers who process personally identifiable information (PII) to assess risk and implement controls for protecting PII. It was published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) under the joint ISO and IEC subcommittee, ISO/IEC JTC 1/SC 27.
Standard Versions
There have been two editions of this standard so far:
ISO/IEC 27018:2014
ISO/IEC 27018:2019
Structure of the standard
ISO/IEC 27018:2019 has eighteen sections, plus a long annex, which cover:
1. Scope
2. Normative References
3. Terms and definitions
4. Overview
5. Information security policies
6. Organization of information security
7. Human resource security
8. Asset management
9. Access control
10. Cryptography
11. Physical and environmental security
12. Operations security
13. Communications security
14. System acquisition, development and maintenance
15. Supplier relationships
16. Information security incident management
17. Information security aspects of business continuity management
18. Compliance
Objectives
When used in conjunction with the information security controls in ISO/IEC 27002, ISO/IEC 27018 suggests a set of security controls that can be implemented by a public cloud computing service provider acting as a PII processor.
The objectives of the standard are to:
Help the public cloud service provider to comply with applicable obligations when acting as a PII processor, whether such obligations fall on the PII processor directly or through contract.
Enable the public cloud PII processor to be transparent in relevant matters so that cloud service customers can select well-governed cloud-based PII processing services.
Assist the cloud service customer and the public cloud PII processor in entering into a contractual agreement.
Provide cloud service customers with a mechanism for exercising audit and compliance rights and responsibilities in cases where individual cloud service customer audits of data hosted in a multiparty, virtualized server (cloud) environment can be impractical technically and can increase risks to those physical and logical network security controls in place.
Advantages
Using this standard has the following advantages:
It provides a higher security to customer data and information.
It makes the platform more reliable to the customer, achieving a higher level than the competition.
Faster enablement of global operations.
Streamlined contracts.
It provides legal protections for cloud providers and users.
References
External links
ISO Website
Computer security standards
Information assurance standards
27018 | ISO/IEC 27018 | [
"Technology",
"Engineering"
] | 549 | [
"Computer security standards",
"Computer standards",
"Information assurance standards",
"Cybersecurity engineering"
] |
63,499,928 | https://en.wikipedia.org/wiki/NGC%20824 | NGC 824 is a barred spiral galaxy located in the constellation Fornax about 260 million light-years from the Milky Way. It was discovered by British astronomer John Herschel in 1837.
See also
List of NGC objects (1–1000)
References
Barred spiral galaxies
0824
Fornax
008068 | NGC 824 | [
"Astronomy"
] | 64 | [
"Fornax",
"Constellations"
] |
63,502,168 | https://en.wikipedia.org/wiki/Zoombombing | Zoombombing or Zoom raiding is the unwanted, disruptive intrusion, generally by Internet trolls, into a video-conference call. In a typical Zoombombing incident, a teleconferencing session is hijacked by the insertion of material that is lewd, obscene, or offensive in nature, typically resulting in the shutdown of the session or the removal of the troll. The term is especially associated with and is derived from, the name of the Zoom videoconferencing software program; however, it has also been used to refer to the phenomenon on other video conferencing platforms. The term became popularized in 2020 when the COVID-19 pandemic forced many people to stay at home, and videoconferencing came to be used on a large scale by businesses, schools, and social groups.
Zoombombing has caused significant issues in particular for schools, companies, and organizations worldwide. Such incidents have resulted in increased scrutiny on Zoom as well as restrictions on usage of the platform by educational, corporate, and governmental institutions globally. In response, Zoom, citing the sudden influx of new users due to the COVID-19 pandemic, took measures to increase security of its teleconferencing application. Incidents of Zoombombing have prompted law enforcement officers in various countries to investigate such cases and file criminal charges against those responsible.
Etymology
The term Zoombombing is a neologism derived from the teleconferencing application Zoom and influenced by the word photobombing. The term had appeared in mid-March 2020 on technology and news websites. Zoombombing has also been used in reference to similar incidents on other teleconferencing platforms, such as WebEx or Skype.
Methods
The increased use of Zoom during the COVID-19 pandemic as an alternative to face-to-face meetings resulted in widespread exposure to hackers and Internet trolls, who exploit and work around the application's security features. In various forums such as Discord and Reddit, efforts have been coordinated to disrupt Zoom sessions, while certain Twitter accounts advertise meeting IDs and passwords or meeting links (allowing users to instantly join a Zoom meeting instead of entering the credentials required to access a meeting) for sessions that were vulnerable to being joined without authorization. At educational institutions, some students were "actively asking strangers to Zoombomb or 'Zoom raid' their virtual classrooms to spice up their isolated lessons" and facilitating the raids by sharing passwords with the raiders. CNET pointed out that simple Google searches for URLs that include "Zoom.us" could bring up conferences that are not password protected, and that links within public pages can allow anyone to join. Hackers and trolls also look for easy targets such as unprotected or underprotected "check-in" meetings in which organizations meet with their employers or clients remotely.
While a Zoom session is in progress, unfamiliar users show up and hijack the session by saying or showing things that are lewd, obscene, or racist in nature. The compromised Zoom session is then typically shut down by the host. Many of those successful in disrupting sessions have posted video footage of those incidents to social media and video sharing platforms such as TikTok and YouTube.
While it is believed Zoombombing attacks are mainly orchestrated by external hackers and trolls, many are also orchestrated internally from within their respective organization or entity. Some view Zoombombing as a continuation of cyberbullying by teenagers, particularly after schools were shut down due to the pandemic.
Responses
Zoombombings would frequently make the local news for how disruptive they are.
The trolling has caused a number of problems for schools and educators, with unwanted participants posting lewd content to interrupt learning sessions. Some schools had to suspend using video conferencing altogether. The University of Southern California called Zoombombing a type of trolling and apologized for "vile" events that interrupted "lectures and learning." Zoombombing has prompted colleges and universities to publish guides and resources to educate and bring awareness to their students and staff about the phenomenon. Zoombombing has left online lectures vulnerable to the intrusion of people looking to inflict harm. These crimes have brought attention not only to the lack of security on videoconferencing platforms, but also the lack in the universities. According to an article from The Guardian, the University of Warwick, in the midst of a rape-chat scandal, received criticisms for its weak cybersecurity.
Zoombombing affected twelve-step programs such as Alcoholics Anonymous and Narcotics Anonymous and other substance abuse and addiction recovery programs who were forced to switch to online meetings. Concerns arise from causing undue stress to an already vulnerable population and video recording which can break anonymity. Some bombers reference the drug-of-choice for recovery members, such as alcohol, in an attempt to emotionally trigger the participants of the meeting.
The problem reached such prominence that the United States Federal Bureau of Investigation (FBI) warned of video-teleconferencing and online classroom hijacking, which it called "Zoom-bombing." The FBI advised users of teleconferencing software to keep meetings private, require passwords or other forms of access control such as "waiting rooms" to limit access only to specific people, and limiting screen-sharing access to the meeting host only. Given the number of incidents of Zoombombing, New York's attorney general initiated an inquiry into Zoom's data privacy and security policies. U.S. Senator Sherrod Brown (D-OH) asked the Federal Trade Commission to investigate into the matter, accusing Zoom of engaging in deceptive practices regarding user privacy and security.
Amid concerns about Zoombombing, various organizations banned the use of Zoom. In April 2020, Google banned the use of Zoom on its corporate computers, directing employees to instead use its video chat app Google Duo. The use of Zoom was also banned by SpaceX, Smart Communications, NASA, and the Australian Defence Force. The Taiwanese and Canadian governments banned Zoom for all government use. The New York City Department of Education prohibited all its teachers from using the platform with students, and the Clark County School District in Nevada disabled access to Zoom to its staff. Singapore's Ministry of Education briefly banned all teachers within the country from using Zoom before lifting the ban three days later, adding extra security features. Some Zoombombers have shared their side of the story, claiming they aren't trying to cause harm. They claim it is a form of protest in response to the extensive amount of work given from teachers. Not all incidents are malicious, as many have shared some new pop culture, such as memes and TikToks, to bring some relief and fun during the pandemic.
Zoom CEO Eric Yuan made a public apology, saying that the teleconferencing company had not anticipated the sudden influx of new consumer users and stating that "this is a mistake and lesson learned." In response to the concerns, Zoom has published a guide on their blog on how to avoid these types of incidents. On April 7, 2020, Zoom implemented user experience and security updates to the application. Such updates include a more visible "Security" icon for users to see and use, suppression of meeting ID numbers, and a change in the default settings to require passwords and waiting rooms for sessions. On April 8, 2020, Zoom announced that it had formed a council of chief information security officers from other companies to share ideas on best practices, and that it had hired Alex Stamos, former chief security officer of Facebook, as an adviser. Zoom released its 5.0 version in April 2020 with security features that include AES 256-bit GCM encryption, passwords by default, and a feature to report suspicious users to its Trust and Safety Team for possible misuse. In May 2020, Zoom announced it had temporarily disabled its Giphy (frequently used as a tactic in Zoombombing) integration until security concerns could be properly and fully addressed. On July 1, 2020, Zoom stated it had released 100 new safety features over the past 90 days, including end-to-end encryption for all users, turning on meeting passwords by default, giving users the ability to choose which data centers calls are routed from, consulting with security experts, forming a CISO council, an improved bug bounty program, and working with third parties to help test security.
Criminal use
National authorities worldwide warned of possible charges against people engaging with Zoombombing. On April 8, 2020, a teen in Madison, Connecticut, was arrested for computer crime, conspiracy, and disturbing the peace following a Zoombombing incident involving online classes at Daniel Hand High School; police also identified another teen involved in the incident. In San Francisco, a man was arrested after being traced to pornographic videos that were streamed on Zoom. As of May 2020, the FBI has received 195 incidents of Zoombombing involving child abuse, while the United Kingdom's National Crime Agency has reported more than 120 such cases.
Notable incidents
St. Paulus Lutheran Church in San Francisco filed a class-action lawsuit against Zoom after one of its Bible study classes was "Zoombombed" on May 6, 2020. The church alleged that Zoom "did nothing" when it tried to reach out to the company.
In November 2020, a Dutch journalist for RTL Nieuws managed to gain access to a secret Zoom meeting of European Union defence ministers. The EU's foreign affairs representative Josep Borrell told him that it was criminal offense and he should sign off before the police arrived. The Zoombomb was revealed to have been the result of the Dutch defence minister Ank Bijleveld posting a picture of herself that showed the login and the partial PIN number.
In 2022, an online event hosted by the Italian Senate's Movimento 5 Stelle and broadcast live to Senato della Repubblica was interrupted by roughly a minute of a 3D animated Final Fantasy VII pornographic parody, displaying the character Tifa Lockhart in the middle of sexual intercourse. Overlapping the content's original audio was a man speaking English with a thick Italian accent stating, "I used to be a sex offender, but now I am a kindergarten teacher."
Brian Adams, a man from Paintsville, Kentucky, faced multiple federal charges after he interrupted an elementary school's video conference class during the COVID-19 pandemic with a digital racist threat. He allegedly crashed a class Zoom conference on October 14, 2020, and targeted the Laureate Academy Charter School, whose student population is about 67% Black, because of its racial demographics.
In 2020, livestreamer Muudea Sedik, better known as twomad, gained popularity for his Zoom bombings. Sedik would request Zoom meeting links or passwords from his followers on social media, and would broadcast the subsequent invasions live. Sedik's antics made him a popular subject for various internet memes, particularly among Generation Z.
See also
Photobombing
Email bomb
Text message bomb
Google bombing
Griefing
Trolling
References
Criticisms of software and websites
Hacking in the 2020s
Internet memes introduced in 2020
Internet trolling
Online obscenity controversies
Videotelephony
2020 neologisms
2020s neologisms
Zoom (software) | Zoombombing | [
"Technology"
] | 2,323 | [
"Criticisms of software and websites"
] |
63,502,883 | https://en.wikipedia.org/wiki/EN%20301%20549 | EN 301 549 is a European standard that supports the development of digital best practices for everyone, including people with disabilities. It's like a checklist for digital accessibility that creators use to make sure their technology is easy for everyone to use. It specifies requirements for information and communications technology to be accessible for people with disabilities. For the web, the latest version, EN 301 549 v 3.2.1 includes the full text of WCAG 2.1 AA.
History of EN 301 549
This standard was produced by CEN, CENELEC and ETSI to set requirements for products and services in the European Union. EN 301 549 is the harmonized European Standard for ICT Accessibility. It is used in public procurement, as it is important that government services are easy for everyone to use. With European Accessibility Act, it is applicable to most organizations in Europe. Since it started, the rules have been updated to keep up with best practices.
Versions over time
EN 301 549:2015 V1.1.2 (Date: 2015-04)
EN 301 549:2018 V2.1.2 (Date: 2018-08)
EN 301 549:2019 V3.1.1 (Date: 2019-11)
EN 301 549:2021 V3.2.1 (Date: 2021-03)
CAN/ASC - EN 301 549:2024 (Date: 2024-05)
Why digital standards matter
EN 301 549 has generally adopted the latest recommended version of Web Content Accessibility Guidelines from the W3C's Web Accessibility Initiative, after a period of review. In version 2.1.2 the Harmonized Accessibility Standards officially adopted the W3C's WCAG 2.1 guidelines. Previous versions of EN 301 549 embraced WCAG 2.0 as an ‘electronic attachment’. The next version of EN 301 549 (v4.1.1) will be released in 2026. This new version is planned to support the European Accessibility Act and to include WCAG 2.2 AA, as well as significant updates to requirements related to Real-Time Text.
The EU approved the Web Accessibility Directive before this harmonized standard had been developed. The implemented decision provides for the presumption of conformity between member states. Having a global guideline like WCAG is great, but it is easier to implement for some countries as a clear standard. Member states had until September 2018 to create the laws and regulations which enforce the relevant accessibility requirements. Members states are free to determine how they achieve the standards of EN 301 549 standard and may exceed them. However, they now constitute a minimum standard for accessibility for European governments.
What is included
The standard includes web and mobile applications but also addresses a wide range of other technologies beside those covered by WCAG:
Information and communications technology (ICT) products;
Services related to products;
Web sites; and
Some specific telecommunications services necessary to provide alternative modes of communication for speech modality (such as text or images) and their routing could offer access to services such as emergency calls or relay services for everyone.
Expectations for European governments
European public entities are expected to meet the following deadlines:
Requirements are already in force for any website published since September 23, 2019.
Public websites (including existing sites) are required to comply by September 23, 2020.
Mobile apps in the public sector are required to comply by June 23, 2021.
Global Adoption
Countries outside of Europe, like Australia and Canada, are also using these rules. This helps them make their technology easier for everyone to use and keeps their standards in line, which facilitates trade with Europe. Even where it hasn't been yet adopted, it is being used as a bench-mark for evaluating digital accessibility.
In 2024, Canada adopted the current (2021) version of the European Union's EN 301 549, as CAN/ASC - EN 301 549:2024. It is now a National Standard of Canada. Their version is identical to the original, but is available not only in PDF format but also in MS Word and HTML formats. The Canadian version is also available in French.
Future updates
The rules are updated regularly to keep up with new technology. The next big update will be in 2025, and it will include the newest advice on how to make technology accessible.
See also
Section 508 Amendment to the Rehabilitation Act of 1973
Web Accessibility Directive
European Accessibility Act
References
External links
Deque: EU Web Accessibility Compliance and Legislation
EN 301 549: Essential Accessibility: The European Standard for Digital Accessibility
EU Directive on the Accessibility of Public Sector Websites and Mobile Applications
EU Web Accessibility Laws: EN 301 549 and EAA
EN 301 549 V3 the harmonized European Standard for ICT Accessibility
EN standards
Accessibility
Accessible procurement
Disability legislation
Disability in law | EN 301 549 | [
"Engineering"
] | 971 | [
"Accessibility",
"Design"
] |
63,503,384 | https://en.wikipedia.org/wiki/Web%20Accessibility%20Directive | The Directive on the accessibility of websites and mobile applications also known as Directive (EU) 2016/2102 was adopted by the European Union (EU) in 2016. This Directive applies to public sector organizations of member states of the European Union. The goal was to ensure that all public sector organizations were accessible for the 80 million people with disabilities in the EU.
This EU Directive gave each member state until 2018 to be transposed into national legislation. Each member country is responsible for implementing national legislation that conforms. A minimum level of harmonization is required which Member States must maintain. National legislation can exceed these minimum requirements, and some countries have chosen to do so. In transposing this EU Directive to national legislation, there was no need to extend it beyond the public sector organizations, but France chose to go beyond the minimum.
The Web Accessibility Directive Expert Group (WADEX) was established to provide support on the implementation of the Directive.
The EU also implemented four Commission Implementing Decisions to complete the directive. These implementing decisions are legally binding acts within the European Union and are directly applicable in all member states of the EU. "Implementing decisions are always limited in scope. Their aim is to ensure uniform implementation of European legislation, and the subject-matter of any implementing decision serves that goal alone." The related implementing decisions provide a model accessibility statement (2018/1523), monitoring methodology and arrangements for reporting (2018/1524), harmonised standard for websites and mobile application (2018/2048, updated by 2021/1339).
The EU's new European Accessibility Act complements the Web Accessibility Directive and applies to the private sector, thus impacting a much larger number of people.
Implications of this Directive
The Directive:
addresses websites and apps of public sector organizations;
refers to specific standards, such as EN 301 549;
requires the publication of an accessibility statement for websites and mobile apps;
calls for a feedback mechanism for users to flag accessibility problems;
expects regular accessibility monitoring and corresponding public reports by Member States.
There is no specific reference to the Authoring Tool Accessibility Guidelines (ATAG) 2.0, but Note 2: clause 48 talks both promoting authoring tools that help with accessibility and the recommendation to fund their development.
The EC is also supporting the financing of research and pilot projects such as
World Wide Web Consortium (W3C)'s Web Accessibility Initiative (WAI) - WAI-Tools to establish uniform accessibility testing rules;
W3C-WAI - WAI-Guide to design educational material;
WADcher to develop a WAD platform prototype for evaluation, monitoring and reporting for WAD;
Funka Nu AB - We4Authors to facilitates the incorporation of accessibility features as the default option in authoring tools.
Timeline for Implementation
23 September 2018 - Member States must transpose this Directive to national legislation
23 September 2019 - all new public sector websites must conform
23 September 2020 - all public sector websites must conform
23 June 2021 - all mobile apps must conform
23 December 2021 - member states' websites will need to be monitored and publicly reported
23 June 2022 - European Commission to carry out a review of the application of this directive (Article 13).
Accessibility Monitoring and Reporting
Member States' have assigned organizations which are in charge of monitoring the implementation of the Web Accessibility Directive. Among other tasks, these organizations are responsible for regular monitoring of public sector sites, review disproportionate burden cases and accessibility statements, and guarantee both accessibility compliance and effective handling of feed-back given by users. The European Commission's 2022 eGovernment Benchmark compares how governments across Europe deliver digital public services.
2020-2021 Reports
A full public list of EU monitoring reports produced because of the Web Accessibility Directive is available per country. This included the
UK: Accessibility report of public sector websites and mobile apps due to the Agreement on the withdrawal of the United Kingdom from the European Union. All member states aside from France and Cyprus have published their monitoring reports. Luxembourg's Digital accessibility monitoring in Luxembourg, Ireland's Monitoring Report EU WAD Ireland 2021 and Malta's Report on the outcome of the monitoring and use of the enforcement procedure were written in English. Both Slovenia and Portugal also included an English translation. All other reports were translated to English using fully automated machine translation.
Every three years, member states are required to provide reporting. The next reports will be due in December 2024.
See also
European Accessibility Act for the private and non-profit sectors.
Accessible Canada Act for the corresponding Federal Canadian legislation.
Disability Discrimination Act for the corresponding UK legislation.
Americans with Disabilities Act of 1990 for the corresponding American federal legislation.
References
External links
Lainey Feingold's Global Law and Policy: Europe
European Union directives
Accessibility
2016 in Europe
2016 in law
Disability legislation | Web Accessibility Directive | [
"Engineering"
] | 959 | [
"Accessibility",
"Design"
] |
63,504,856 | https://en.wikipedia.org/wiki/Women%20in%20Mathematics%20%28book%29 | Women in Mathematics is a book on women in mathematics. It was written by Lynn M. Osen, and published by the MIT Press in 1974.
Topics
The main content of the book is a collection of eight biographies of women mathematicians, arranged chronologically, with an additional introductory chapter and two closing chapters. The mathematicians profiled here are Hypatia, Maria Gaetana Agnesi, Émilie du Châtelet, Caroline Herschel, Sophie Germain, Mary Somerville, Sofya Kovalevskaya, and Emmy Noether.
One of the two closing chapters features shorter profiles of additional women mathematicians, "rather curiously selected" and "mostly working in America". The scientists mentioned in this chapter are Mary W. Gray, Mina Rees, Lise Meitner, Maria Goeppert Mayer, Charlotte Scott, Hanna Neumann, Maria Pastori, Maria Cibrario, Jacqueline Lelong-Ferraud, Paulette Libermann (misspelled Liberman), Sophie Piccard (misspelled Picard), Olga Taussky-Todd, Emma Lehmer (misspelled Lermer), Julia Robinson, Elizabeth Scott, Grace Hopper and Dorothy Maharam Stone.
Reception
Although reviewer Philip Peak found the book "interesting and useful", and reviewer writes that it is written in a pleasant style, most reviewers were not as positive. Hardy Grant writes that Osen's profile of Hypatia has treated her "very badly" by being based primarily on a piece of fiction for children written in the early 20th century by Elbert Hubbard. Reviewer R. P. Infante writes that "Osen does not seem to know much mathematics or its history", pointing to several errors in both. Infante also bemoans the book's "narrow" and "slipshod" scholarship, consisting of vague attributions to "some scholars" in the text of the work that "invariably" lead to the work of a single author, early 20th century writer John Augustine Zahm. Reviewer suggests that Grace Chisholm Young should have been mentioned. And reviewers Margaret Hayman and Edith Robinson both complain about the book's focus on its subjects' victimization by society, rather than either their personal lives and personalities or their mathematical accomplishments. Michael A. B. Deakin wrote, "Sadly, the standard of Osen's scholarship did not match the importance of her subject matter."
References
External links
Women in Mathematics at the Internet Archive
Women in mathematics
Biographies and autobiographies of mathematicians
1974 non-fiction books | Women in Mathematics (book) | [
"Technology"
] | 523 | [
"Women in science and technology",
"Women in mathematics"
] |
63,504,884 | https://en.wikipedia.org/wiki/Reproductive%20assurance | Reproductive assurance (fertility assurance) occurs as plants have mechanisms to assure full seed set through selfing when outcross pollen is limiting. It is assumed that self-pollination is beneficial, in spite of potential fitness costs, when there is insufficient pollinator services or outcross pollen from other individuals to accomplish full seed set.. This phenomenon has been observed since the 19th century, when Darwin observed that self-pollination was common in some plants. Constant pollen limitation may cause the evolution of automatic selfing, also known as autogamy. This occurs in plants such as weeds, and is a form of reproductive assurance. As plants pursue reproductive assurance through self-fertilization, there is an increase in homozygosity, and inbreeding depression, due to genetic load, which results in reduced fitness of selfed offspring. Solely outcrossing plants may not be successful colonizers of new regions due to lack of other plants to outcross with, so colonizing species are expected to have mechanisms of reproductive assurance - an idea first proposed by Herbert G. Baker and referred to as Baker's "law" or "rule". Baker's law predicts that reproductive assurance affects establishment of plants in many contexts, including spread by weedy plants and following long-distance dispersal, such as occurs during island colonization. As plants evolve towards increase self-fertilization, energy is redirected to seed production rather than characteristics that increased outcrossing, such as floral attractants, which is a condition known as the selfing syndrome.
Evolution
Reproductive assurance is thought to be a driver for the evolution of selfing because it would promote purging of genetic load and it contributes to the occurrence of mixed mating systems. There are a number of mechanisms that result in reproductive assurance, but delayed selfing has been the one most studied. When pollination is unsuccessful, full seed set can be obtained through delayed selfing. Most hermaphrodite plants are self-compatible, meaning they are able to self-fertilize. When pollinators routinely fail to deliver adequate outcross pollen to ensure reproduction, selfing may increase through mechanisms of reproductive assurance, leading to the evolution of complete selfing.
Mechanisms
Mechanisms of reproductive assurance include:
Delayed selfing
A common reproductive assurance mechanism that occurs in plants that are able to reproduce by self-fertilization by changing the position of the anthers and stigma within the flower to promote self-pollination.
Cryptic self-incompatibility (CSI)
Cryptic self-incompatibility favors fertilization by outcrossing pollen, when both outcross and self-pollen are present on the same stigma. CSI promotes fertilization by outcross pollen due to faster growth rate of outcross pollen tubes. Reproduction assurance occurs when there is insufficient outcross pollen present to attain fertilization of all of the ovules.
Autogamy
Similar to delayed selfing, fertilization via autogamy occurs when there is a lack of pollinators and has evolved as a form of reproductive assurance to ensure successful reproduction.
Cleistogamy
Cleistogamous flowers are produced along with chasmogamous flowers on the same plant resulting in a mixed mating system that ensures reproductive success through autogamy.
References
Plant reproduction | Reproductive assurance | [
"Biology"
] | 667 | [
"Behavior",
"Plant reproduction",
"Plants",
"Reproduction"
] |
63,505,865 | https://en.wikipedia.org/wiki/IBM%20Enterprise%20Systems%20Architecture | IBM Enterprise Systems Architecture is an instruction set architecture introduced by IBM as ESA/370 in 1988. It is based on the IBM System/370-XA architecture.
It extended the dual-address-space mechanism introduced in later IBM System/370 models by adding a new mode in which general-purpose registers 1-15 are each associated with an access register referring to an address space, with instruction operands whose address is computed with a given general-purpose register as a base register will be in the address space referred to by the corresponding address register.
The later ESA/390, introduced in 1990, added a facility to allow device descriptions to be read using channel commands and, in later models, added instructions to perform IEEE 754 floating-point operations and increased the number of floating-point registers from 4 to 16.
Enterprise Systems Architecture is essentially a 32-bit architecture; as with System/360, System/370, and 370-XA, the general-purpose registers are 32 bits long, and the arithmetic instructions support 32-bit arithmetic. Only byte-addressable real memory (Central Storage) and Virtual Storage addressing is limited to 31 bits, as is the case with 370-XA. (IBM reserved the most significant bit to easily support applications expecting 24-bit addressing, as well as to sidestep a problem with extending two instructions to handle 32-bit unsigned addresses.) It maintains problem state backward compatibility dating back to 1964 with the 24-bit-address/32-bit-data (System/360 and System/370) and subsequent 24/31-bit-address/32-bit-data architecture (System/370-XA). However, the I/O subsystem is based on System/370 Extended Architecture (S/370-XA), not on the original S/370 I/O instructions.
ESA/370 architecture
On February 15, 1988, IBM announced
Enterprise Systems Architecture/370 (ESA/370) for 3090 enhanced ("E") models and for 4381 model groups 91E and 92E.
In addition to the primary-space and secondary-space addressing modes that later System/370 models, and System/370 Extended Architecture (S/370-XA) models, support, ESA has an access register mode in which each use of general register 1-15 as a base register uses an associated access register to select an address space. In addition to the normal address spaces that machines with the dual-address-space facility support, ESA also allows data spaces, which contain no executable code.
A machine may be divided into Logical Partitions (LPARs), each with its own virtual system memory so that multiple operating systems may run concurrently on one machine.
ESA/390 architecture
An important capability to form a Parallel Sysplex was added to the architecture in 1994.
ESA/390 also extends the Sense ID command to provide additional information about a device, and additional device-dependent channel commands, the command codes for which are provided in the Sense ID information, to allow device description information to be fetched from a device.
Starting with the System/390 G5, IBM introduced:
the basic floating-point extensions facility, which increases the number of floating-point registers from 4 (0, 2, 4, 6) to 16 (0-15);
the binary floating-point (BFP) extensions facility, which supports IEEE 754 binary floating-point numbers, with an additional floating-point control (FPC) register to support IEEE 754 modes and errors;
the floating-point support (FPS) extensions facility, which adds instructions to load and store floating-point numbers regardless of whether they're in hexadecimal or IEEE 754 format and to convert between those formats;
the hexadecimal floating-point (HFP) extensions facility, which adds new hexadecimal floating-point instructions corresponding to some binary floating-point instructions.
Some PC-based IBM-compatible mainframes which provide ESA/390 processors in smaller machines have been released over time, but are only intended for software development.
New facilities
ESA/390 adds the following facilities
All models
Access-list-controlled protection
Some models
Concurrent sense
PER 2
Storage-protection override
Move-page facility 2
Square root
String instruction
Suppression on protection with virtual-address enhancement
Set address space control fast
Subspace group
Called-space identification
Checksum
Compare and move extended
Immediate and relative instruction
Branch and set authority
Perform locked operation
Additional floating-point
Program call fast
Resume program
Trap
Extended TOD clock
TOD-clock-control override
Store system information
Extended translation 1
Extended translation 2
z/Architecture (certain instructions)
Enhanced input/output
New channel commands
The following channel commands are new, or have their functionality changed, in ESA/390:
Notes
References
S370-ESA
S/390-ESA
Enterprise Systems Architecture
Computing platforms
Computer-related introductions in 1988
2000s disestablishments
32-bit computers | IBM Enterprise Systems Architecture | [
"Technology"
] | 1,011 | [
"Computing platforms"
] |
63,506,592 | https://en.wikipedia.org/wiki/NGC%20734 | NGC 734 is a lenticular galaxy with a central bar in the constellation Cetus, which is about 538 million light years from the Milky Way. It was discovered on November 9, 1885, by the American astronomer Francis Preserved Leavenworth.
NGC 734 was identified as PGC 170023, but is often misidentified as PGC 7121. SIMBAD also shows the position of NGC 734 as PGC 7121.
See also
List of NGC objects (1–1000)
References
External links
734
Barred lenticular galaxies
Cetus | NGC 734 | [
"Astronomy"
] | 114 | [
"Cetus",
"Constellations"
] |
63,506,637 | https://en.wikipedia.org/wiki/NGC%20736 | NGC 736 is an elliptical galaxy in the constellation Triangulum. It is an estimated 200 million light years from the Milky Way and has a diameter of approximately 85,000 light years. NGC 736 was discovered on September 12, 1784 by the German-British astronomer William Herschel.
See also
List of NGC objects (1–1000)
References
External links
736
Triangulum
Elliptical galaxies
007289 | NGC 736 | [
"Astronomy"
] | 85 | [
"Triangulum",
"Constellations"
] |
63,506,979 | https://en.wikipedia.org/wiki/Ganpat%20Patel | Ganpat Patel (born 1945 or 1946), also known as Pat Patel, is an Indian-American scientist and philanthropist. He is the founder of Charokee International and was President and CEO before retiring in 2004.
Patel is the President and Pado-in-Chief of Ganpat University located in the Mehsana district of North Gujarat.
Patel is also advisor in fotonVR and chairman in Guniguru.
Patel was honored with the Padma Shri award in the literature and education category.
Early life and education
Ganpat Patel is the son of Iswarbhai Patel and Menaben Patel. He was born in the village of Bhunav in Mehsana, Gujarat in 1945 or 1946. He received a bachelor of science degree in electrical engineering from California State Polytechnic University, in Pomona in 1969 and a master's degree, also in electrical engineering, from UCLA in 1973.
Career
Patel got his first job in an aviation industry company Lockheed Martin but he lost this job soon due to a recession in the aviation sector. He was lucky to get the immediate job offer from Abbott Laboratories in Culver City of Los Angeles in 1971. There after he also got an opportunity in Burroughs Computer and he acquired many useful skills which gave a great push to the tenets of entrepreneurship in him. In 1978, Shri Patel, with the help of his wife, founded Cherokee International, Inc., a power supply company. Cherokee secured relationships with businesses like IBM, CISCO, Motorola, and Hewlett Packard and opened manufacturing facilities in the United States, India, Belgium, and Mexico. Patel retired from his professional career in 2004.
Personal life
His wife, Majnu Patel, is a social worker and philanthropic. She runs a sainik school for girls in her name "Smt M.G. Patel Sainik School for Girls" in North Gujarat, India and making sure that 400+ girls get their schooling education every year through this military school. She does philanthropic work with the help of her husband Ganpat Patel and her family.
Supported by his wife Smt Manjuben and motivated by his three daughters, Rita, Anita and Asha as well as his seven grandchildren, Patel has started a “सेवा यज्ञ” social upliftment through education and established various institutions in India which can impart quality learning to Indian students.
Awards and honors
References
External links
1940s births
Living people
Gujarati people
Indian billionaires
Businesspeople from Los Angeles
Electric power
University and college founders
Indian electrical engineers
Indian philanthropists
Indian emigrants to the United States
American people of Indian descent
American people of Gujarati descent
California State Polytechnic University, Pomona alumni
American billionaires
American electrical engineers
American philanthropists | Ganpat Patel | [
"Physics",
"Engineering"
] | 542 | [
"Power (physics)",
"Electrical engineering",
"Electric power",
"Physical quantities"
] |
63,507,558 | https://en.wikipedia.org/wiki/Aloxistatin | Aloxistatin (loxistatin, E-64d, EST) is a drug which acts as a cysteine protease inhibitor and has anticoagulant effects. It is a synthetic analogue of E-64, a natural product derived from fungi. It was researched for the treatment of muscular dystrophy but was not successful in human clinical trials, though it has continued to be investigated for treatment of spinal cord injury, stroke and Alzheimer's disease.
Aloxistatin also shows antiviral effects. Studies have shown it can inhibit cathepsin L, a protein believed to play a role in SARS-CoV-2 cellular entry. In a laboratory study using SARS-CoV-2 pseudovirions, aloxistatin was able to reduce viral entry into cells by approximately 92%.
References
Anticoagulants
Ethyl esters
Epoxides
Carboxamides
Dipeptides
Experimental antiviral drugs
COVID-19 drug development | Aloxistatin | [
"Chemistry"
] | 206 | [
"Pharmacology",
"Drug discovery",
"Medicinal chemistry stubs",
"COVID-19 drug development",
"Pharmacology stubs"
] |
69,215,392 | https://en.wikipedia.org/wiki/ITU-R%20BT.1886 | ITU-R BT.1886 is the reference EOTF of SDR-TV. It is a gamma 2.4 transfer function (a power law with a 2.4 exponent) considered as a satisfactory approximation of the response characteristic of CRT to electrical signal. It has been standardized by ITU in March 2011. It is used for Rec. 709 (HD-TV) and Rec. 2020 (UHD-TV).
Definition
BT.1886 EOTF is as follows:
where
is the screen luminance, in cd/m2.
is the input video signal level, in the range .
is the exponent of the power function and equal to 2.4
is the variable for user gain (legacy “contrast” control)
is the variable for user black level lift (legacy “brightness” control)
is the screen luminance for white, in cd/m2.
is the screen luminance for black, in cd/m2.
According to ITU, for a better match, can be set to 0.1 for moderate black level settings (e.g. 0.1 cd/m2) or to 0 for lower black levels (e.g. 0.01 cd/m2).
An alternative EOTF has also been provided by ITU for the cases a more precise match of CRT characteristics is required.
See also
Gamma correction
Transfer functions in imaging
References
ITU-R recommendations
Transfer functions
Display technology | ITU-R BT.1886 | [
"Engineering"
] | 296 | [
"Electronic engineering",
"Display technology"
] |
69,215,443 | https://en.wikipedia.org/wiki/Rubidium%20ozonide | Rubidium ozonide is an oxygen rich compound of rubidium. It is an ozonide, meaning it contains the ozonide anion (O3−).
It can be created by reacting rubidium superoxide (RbO2) with ozone (O3) in a liquid ammonia solution.
RbO2 + O3 -> RbO3 + O2
The chemical forms in two crystal structures, the low temperature α-RbO3 (P21), and β-RbO3 (P21/c) Detailed structural analysis finds the ozonide anions are significantly off-center from the surrounding rubidium atoms.
Since ozonide anion is magnetic, electron paramagnetic resonance measurements of rubidium ozonide have determined the g-values of the ozonide anion.
References
Rubidium compounds
Ozonides | Rubidium ozonide | [
"Chemistry"
] | 177 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
69,216,364 | https://en.wikipedia.org/wiki/Daniel%20Deocampo | Daniel Michael Deocampo is an American geologist, geochemist, and academic administrator. He was an associate dean and professor of geosciences at Georgia State University. Deocampo pleaded guilty to possession of child pornography on November 3, 2021.
Early life and education
Deocampo was born to Helen Deocampo and cardiologist Paulino D. Deocampo of Holmdel Township, New Jersey. He completed a B.S. in geological sciences in 1994 at Tufts University. He earned a M.S. (1997) and Ph.D. (2001) in geological sciences at Rutgers University. His dissertation was titled Geochemistry and Sedimentology of Modern East African Wetlands and a Pleistocene Paleo-Wetland at Olduvai Gorge, Tanzania. His doctoral advisor was Gail Ashley.
He completed a postdoctoral fellowship at the National Museum of Natural History in 2001. In 2002, he was a postdoctoral research hydrologist in the water resources division of the United States Geological Survey in Reston, Virginia. He completed a postdoctoral fellowship at the Natural History Museum, London in 2003.
Career
Deocampo joined the faculty at Georgia State University (GSU) in 2008 as an assistant professor. He became full professor of geosciences in 2016. Deocampo served as the GSU College of Arts and Sciences Associate Dean for Research, Innovation, and Graduate Studies from 2019 to 2021.
In 2014, Deocampo was elected fellow of the Geological Society of America.
Personal life
The Federal Bureau of Investigation (FBI) and GSU Cyber Security identified Deocampo as the individual who had accessed multiple websites containing child pornography (or had links to other websites containing child pornography) from campus in November and December 2020. GSU Cyber Security also advised the FBI that Deocampo routinely accessed the university’s network from home. Based on that information, FBI determined that Deocampo was also accessing websites containing child pornography from his home on several days in late December 2020 and early January 2021. On January 6, 2021, the FBI executed search warrants at Deocampo's residence, as well as his GSU office and lab space. As a result of the search, agents recovered an Apple laptop belonging to Deocampo that contained more than 4,000 files of child pornography, including approximately 190 videos. On November 3, 2021, he pleaded guilty to possession of child pornography. On February 23, 2022, Deocampo was sentenced to 32 months in prison, 10 years of supervised probation, and a $10,100 special assessment.
References
External links
Living people
Year of birth missing (living people)
Place of birth missing (living people)
People from Avondale Estates, Georgia
21st-century American geologists
American geochemists
Fellows of the Geological Society of America
Tufts University School of Arts and Sciences alumni
Rutgers University alumni
Georgia State University faculty
American university and college faculty deans | Daniel Deocampo | [
"Chemistry"
] | 598 | [
"Geochemists",
"American geochemists"
] |
69,216,431 | https://en.wikipedia.org/wiki/G%C3%B6del%20Lecture | The Gödel Lecture is an honor in mathematical logic given by the Association for Symbolic Logic, associated with an annual lecture at the association's general meeting. The award is named after Kurt Gödel and has been given annually since 1990.
Award winners
The list of award winners and lecture titles is maintained online by the Association for Symbolic Logic.
1990 Ronald Jensen, Inner Models and Large Cardinals.
1991 Dana Scott, Will Logicians be Replaced by Machines?
1992 Joseph R. Shoenfield, The Priority Method.
1993 Angus Macintyre, Logic of Real and p-adic Analysis: Achievements and Challenges.
1994 Donald A. Martin, L(R): A Survey.
1995 Leo Harrington, Gödel, Heidegger, and Direct Perception (or, Why I am a Recursion Theorist).
1996 Saharon Shelah, Categoricity without compactness.
1997 Solomon Feferman, Occupations and Preoccupations with Gödel: His *Works* and the Work.
1998 Alexander S. Kechris, Current Trends in Descriptive Set Theory.
1999 Stephen Cook, Logic and computational complexity.
2000 Jon Barwise — cancelled due to the death of the speaker.
2001 Theodore Slaman, Recursion Theory.
2002 Harvey Friedman, Issues in the foundations of mathematics.
2003 Boris Zilber, Categoricity.
2004 Michael O. Rabin, Proofs persuasions and randomness in mathematics.
2005 Menachem Magidor, Skolem-Lowenheim theorems for generalized logics.
2006 Per Martin-Löf, The two layers of logic.
2007 Ehud Hrushovski — a lecture on his work titled Algebraic Model Theory was given by T. M. Scanlon in his absence.
2008 W. Hugh Woodin, The Continuum Hypothesis, the Conjecture, and the inner model problem of one supercompact cardinal.
2009 Richard Shore, Reverse Mathematics: the Playground of Logic.
2010 Alexander Razborov, Complexity of Propositional Proofs.
2011 Anand Pillay, First order theories.
2012 John R. Steel, The hereditarily ordinal definable sets in models of determinacy.
2013 Kit Fine, Truthmaker semantics.
2014 Julia F. Knight, Computable structure theory and formulas of special forms.
2015 Alex Wilkie, Complex continuations of functions definable in with a diophantine application.
2016 Stevo Todorčević, Basis problems in set theory.
2017 Charles Parsons (philosopher), Gödel and the universe of sets.
2018 Rod Downey, Algorithmic randomness.
2019 Samuel Buss, Totality, provability and feasibility.
2020 Élisabeth Bouscaren, The ubiquity of configurations in Model Theory.
2021 Matthew Foreman, Gödel Diffeomorphisms.
2022 Patricia Blanchette, Formalism in Logic.
2023 Carl Jockusch, From algorithms which succeed on a large set of inputs to the Turing degrees as a metric space.
See also
List of logicians
List of mathematics awards
List of philosophy awards
Karp Prize
Tarski Lectures
References
External links
Official website
Mathematics awards
Philosophy awards
Recurring events established in 1990
Lecture series | Gödel Lecture | [
"Technology"
] | 646 | [
"Science and technology awards",
"Mathematics awards"
] |
69,216,480 | https://en.wikipedia.org/wiki/Catherine%20E.%20Costello | Catherine E. Costello is the William Fairfield Warren distinguished professor in the department of biochemistry, Cell Biology and Genomics, and the director of the Center for Biomedical Mass Spectrometry at the Boston University School of Medicine.
Education
Catherine E. Costello attended the Emmanuel College in Boston for her undergraduate studies in chemistry, and minors in mathematics and physics. She received a Master of Science (1967) and a PhD from Georgetown University (1971). After graduation, she did post-doctoral research with Klaus Biemann at Massachusetts Institute of Technology.
Career
Prior to founding the Center for Biomedical Mass Spectrometry at Boston University School of Medicine in 1994, Costello was a senior research scientist and the associate director of the National Institutes of Health Research Resource for Mass Spectrometry at Massachusetts Institute of Technology for 20 years. She is a William Fairfield Warren Distinguished Professor and the director of the Center for Biomedical Mass Spectrometry at the Boston University School of Medicine.
Costello served as the president of the American Society for Mass Spectrometry (2002–2004), the Human Proteome Organization (2011–2012), and the International Mass Spectrometry Foundation (2014–2018). She currently serves on the board of directors of the US Human Proteome Organization, and the editorial board of Clinical Proteomics.
Research
Her research involves structural characterization of biopolymers using mass spectrometry-based techniques, such as liquid chromatography-mass spectrometry, thin-layer chromatography-mass spectrometry, Fourier-transform ion cyclotron resonance mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, microfluidic capillary electrophoresis-mass spectrometry, and ion mobility spectrometry-mass spectrometry. She was one of the first scientists to characterize glycoconjugates with tandem mass spectrometry. Her 1988 article has been cited over two thousand times. She participated in the Human Proteome Project, the SysteMHC Atlas project, and the Minimum Information Required for a Glycomics Experiment (MIRAGE) project.
Awards
2023 Analytical Scientist the Power List - Leaders and Advocates
2020 Society for Glycobiology Molecular and Cellular Proteomics (MCP) / American Society for Biochemistry and Molecular Biology (ASBMB) Lectureship Award
2019 inaugural winner of the US Human Proteome Organization Lifetime Achievement in Proteomics Award
2019 Analytical Scientist the Power List
2017 American Society for Mass Spectrometry John B. Fenn Award for a Distinguished Contribution in Mass Spectrometry
2016 American Association for the Advancement of Science Fellow
2015 Human Proteome Organization Distinguished Service Award
2015 German Mass Spectrometry Society (Deutsche Gesellschaft für Massenspektrometrie, DGMS) Wolfgang Paul Lecture
2013 Boston University The William Fairfield Warren Distinguished Professorship
2011 American Chemical Society Fellow
2010 American Chemical Society Frank H. Field and Joe L. Franklin Award for Outstanding Achievement in Mass Spectrometry
2009 International Mass Spectrometry Foundation Thomson Medal
2008 Human Proteome Organization Discovery in Proteomic Sciences Award
Awards in her honor
US Human Proteome Organization Catherine E. Costello Lifetime Achievement in Proteomics Award (from 2020)
Females in Mass Spectrometry Catherine E. Costello Award (from 2020)
References
External links
Georgetown University alumni
Emmanuel College (Massachusetts) alumni
Boston University School of Medicine faculty
Thomson Medal recipients
Living people
Mass spectrometrists
American women academics
American women biochemists
Year of birth missing (living people)
21st-century American women
Proteomics
Proteomics journals
Proteomics organizations
Biochemistry | Catherine E. Costello | [
"Physics",
"Chemistry",
"Biology"
] | 756 | [
"Spectrum (physical sciences)",
"Mass spectrometrists",
"Mass spectrometry",
"nan",
"Biochemistry",
"Biochemists"
] |
69,216,621 | https://en.wikipedia.org/wiki/Potassium%20ozonide | Potassium ozonide is an oxygen rich compound of potassium. It is an ozonide, meaning it contains the ozonide anion (O3−). In polarized light, it shows pleochroism. Hybrid functional calculations have predicted the compound is an insulator with a band gap of 3.0 eV, and has magnetic behavior which departs from the Curie–Weiss law.
The compound can be created by reacting ozone with potassium hydroxide, but the yield is quite low, only 5-10%.
The compound is metastable, and will decompose to potassium superoxide and oxygen, especially if there is any water in the atmosphere. Long-term storage in very dry atmosphere is possible below around 0 °C.
This compound reacts with water to form potassium hydroxide and potassium superoxide.
References
Potassium compounds
Ozonides | Potassium ozonide | [
"Chemistry"
] | 176 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
69,216,976 | https://en.wikipedia.org/wiki/Hydronium%20perchlorate | Hydronium perchlorate is an inorganic chemical compound with the chemical formula . It is an unusual salt due to it being a solid and stable hydronium salt. It consists of hydronium cations and perchlorate anions .
Production
Hydronium perchlorate is produced by the reaction of anhydrous perchloric acid and water in a 1:1 molar ratio:
A more analytically reliable method was reported using the macrocyclic Schiff base of sodium 2,6-diformyl-4-methylphenolate and 2,6-diformyl-4-methylphenol as a chelating agent to sequester Cu(II): transmetallation of the macrocycle with copper(II) perchlorate yielded colorless crystals of hydronium perchlorate.
It can also be produced by the reaction of anhydrous nitric acid and perchloric acid.
References
Oxonium compounds
Perchlorates | Hydronium perchlorate | [
"Chemistry"
] | 198 | [
"Perchlorates",
"Salts"
] |
69,217,050 | https://en.wikipedia.org/wiki/Amanita%20princeps | Amanita princeps, the head man slender Caesar, is a species of agaric fungus in the genus Amanita. It is found in tropical China, Southeast Asia, and the Malay Peninsula down to Singapore. It is edible, and is collected in the wild and sold in local markets. Many incidents of mushroom poisoning have occurred among Laotian and Hmong immigrants to North America, since it is easily confused with Amanita phalloides, the death cap, in both appearance and odor.
See also
List of Amanita species
References
princeps
Fungi of Asia
Fungi described in 1962
Taxa named by E. J. H. Corner
Fungus species | Amanita princeps | [
"Biology"
] | 134 | [
"Fungi",
"Fungus species"
] |
69,217,914 | https://en.wikipedia.org/wiki/Popham%20panel | A Popham panel, or T-signalling panel, was a means of ground-to-air communication, in Morse code, developed during the First World War, before the introduction of radio communication. They were named for Robert Brooke-Popham and were used by the British and American armed forces.
They were used in the Waziristan campaign of 1919–1920, and in the Kabul Airlift of 1928, and remained in use as a reserve method of communicating with aircraft as late as just before the Second World War. They were eventually rendered obsolete by the development of effective radio communication with aircraft.
Origin
The Popham panel, first introduced in 1918, was named for First World War Royal Air Force officer, Robert Brooke-Popham, and designed to communicate messages to aircraft from the ground, in Morse code, before the introduction of radio communication.
Operation
Anne Baker described a Popham panel as the size of a "small Persian rug" and structured as a blind. The top of the slats were painted green and from the air, it appeared green when closed. Strong elastic held the slats closed and the operator could pull a cord against the tension of the elastic, to open the blind, showing a white background. The person on the ground could open the panel for a short time, indicating a "dot" in Morse code, or a longer time, indicating a "dash", and thereby had a method of producing a message. If the aircraft located the panel, the air crew could be able to read a message sent by the ground operator. It was aided with a numerical code system, with white numbers in broad strips. One example of a pre-arranged code was "XII", meaning ""come again tomorrow". Andrew Roe described a type that were made from dark blue waterproof American cloth. It weighed around and was about in size, with a white T-shape stitched on. Branching off were further white panels with dark blue flaps, which were numbered one to nine.
Deployment
The panels were used by the British and in the United States, where they were given to battalions, brigades and regiments for communicating with aircraft.
They were used during the Waziristan campaign of 1919–20 on the North-West Frontier of India along with the simpler ground-based signals, but military historian Herman Watteville described them as "of no great value" in that fast-moving conflict. The slow transmission rate was also a problem when aircraft had limited fuel and had to circle for a prolonged period of time to read the more complicated messages, running the risk of having to make an emergency landing in hostile territory. According to Colonel Hugh Pettigrew, who served with the South Waziristan Scouts during the Waziristan campaign (1936–1939), they were aided frequently by the RAF at Miranshah. Often unable to land and sometimes with the wireless not functioning, they had to revert to using old-fashioned land-signals in the form of Popham panels. In his book he gave an account of how one bored base commander laboriously signalled to a pilot as a joke that he wanted the actress Mae West rather than the more usual supplies, and got into a great deal of trouble for doing so. According to Pettigrew the pilot was believed to be Subroto Mukerjee, who later became Chief of the Indian Airforce.
During the Kabul Airlift (1928–1929), on 18 December 1928, Flying Officer Trusk flew a DH.9A, with L. A. C. Donaldson, to Kabul to drop a Popham panel on the grounds of the British Legation in Afghanistan. They had less than 15 minutes to drop the panel, which was to be delivered in two halves; the second half to be dropped if the first was successful and was not captured by the enemy. The complete panel was eventually delivered to the legation by the Afghan Army, after the aircraft had to land nearby due to damage. Subsequently, further Popham panels were sent and were used to deliver messages such as "we are confined to the Legation".
They were still in use as a reserve method of communication prior to the Second World War despite their drawbacks when compared to radio communication.
References
External links
Aviation communications
Aviation in World War I
Optical communications
20th-century inventions
Military equipment of World War I | Popham panel | [
"Engineering"
] | 881 | [
"Optical communications",
"Telecommunications engineering"
] |
69,218,721 | https://en.wikipedia.org/wiki/LGA%204189 | LGA 4189 is an Intel microprocessor compatible socket, used by Cooper Lake and Ice Lake-SP microprocessors.
Two incompatible versions exist: Socket P5 for Cedar Island platform and Cooper Lake, and Socket P4 for Whitley platform and Ice Lake-SP.
References
Intel CPU sockets | LGA 4189 | [
"Technology"
] | 65 | [
"Computing stubs",
"Computer hardware stubs"
] |
69,218,923 | https://en.wikipedia.org/wiki/Science%20Based%20Targets%20initiative | The Science Based Targets initiative (SBTi) is a collaboration between the CDP, the United Nations Global Compact, World Resources Institute (WRI) and the World Wide Fund for Nature (WWF), with a global team composed of people from these organisations. As of 2024, nearly 10,000 companies have science-based climate targets validated by SBTi.
Organization
The Science Based Targets initiative was established in 2015 to help companies to set emission reduction targets in line with climate sciences and Paris Agreement goals. It is funded by IKEA Foundation, Amazon, Bezos Earth Fund, We Mean Business coalition, Rockefeller Brothers Fund and UPS Foundation. In October 2021, SBTi developed and launched the world's first net zero standard, providing the framework and tools for companies to set science-based net zero targets and limit global temperature rise above pre-industrial levels to 1.5 °C. Best practice as identified by SBTi is for companies to adopt transition plans covering scope 1, 2 and 3 emissions, set out short-term milestones, ensure effective board-level governance and link executive compensation to the company's adopted milestones. SBTi offers to validate climate targets set by companies as science-based targets for a fee, resulting in nearly 10,000 companies signing up as of 2024. SBTi removes the validation of climate targets in the event that a company fails to take action to meet its validated targets in a timely manner.
As of 2024, SBTi operates without a central office and has 145 staff who primarily work remotely, including part-time employees. This has led to challenges in meeting the demands of a growing client base of companies seeking SBTi validation for climate targets.
Sector-specific guidance
SBTi developed separate sector-specific methodologies, frameworks and requirements for different industries. As of September 2024, sector guidance is available for:
Aluminium (Scoping phase)
Apparel and footwear (Finalized)
Aviation (In development)
Buildings (Finalized)
Chemicals (In development)
Cement (Finalized)
Financial institutions (Finalized)
Forest, Land and Agriculture (Finalized)
Information and Communication Technology (Finalized)
Land transport (In development)
Maritime (Finalized)
Oil and Gas (In development)
Power (Finalized)
Steel (Finalized)
Carbon offsets controversy
In April 2024 the SBTi Board of Trustees released a statement setting out an intention to permit the use of environmental attribute certificates (EACs) for abatement purposes against Scope 3 emissions reduction targets. SBTi did not previously permit the use of EACs due to the difficulties faced in tracing, measuring and validating their impact. The Bezos Earth Fund, a major funder of the SBTi, exerted influence on SBTi board members to relax the organization's position on carbon offsets. The statement led to a response letter signed by various teams within the SBTi and media speculation about the policy change. The counter argument set out in the response being that carbon offsets are incompatible with the Paris Agreement.
Launched in September 2022, the SBTi's Forestry, Land and Agriculture (FLAG) guidance allows companies to claim the achievement of their emission reduction targets through ‘insetting’, breaking from the long-held SBTi position that emission reduction targets should only be achieved through emission reductions. Insetting is a business-driven concept and not a term defined in international standards and guidelines such as ISO 14050 Environmental Vocabulary and IWA 42 Net zero guidelines.
On 2 July 2024, CEO Luiz Amaral announced that he would step down for personal reasons. In January 2025, David Kennedy was announced as the new CEO, who will be responsible for making a final decision on inclusion of environmental attribute certificates in science based climate targets.
See also
Carbon accounting
Carbon Disclosure Project
Carbon footprint
Carbon neutrality
Carbon offsets and credits
Corporate sustainability
Climate change
Greenhouse gas emissions
Greenhouse gas inventory
Net zero emissions
Paris Agreement
United Nations Global Compact
World Resources Institute
References
Corporate social responsibility
Environmental science
Greenhouse gases
Greenhouse gas emissions
Organizations established in 2015 | Science Based Targets initiative | [
"Chemistry",
"Environmental_science"
] | 804 | [
"Greenhouse gases",
"Greenhouse gas emissions",
"Environmental chemistry",
"nan"
] |
69,219,674 | https://en.wikipedia.org/wiki/Cultural%20heritage%20at%20risk%20from%20climate%20change | Many cultural heritage sites are suffering damage or loss due to anthropogenic climate change. Causes include sea rises and coastal erosion, the increased incidence of extreme weather events such as storms and cyclones, changes in rainfall patterns, extreme periods of drought, and bushfires.
Climate change is an increasing focus of cultural heritage organisations such as the International Council on Monuments and Sites (ICOMOS). UNESCO's List of World Cultural Heritage in Danger includes "threatening impacts of climatic, geological or other environmental factors" as a category of threat.
Sites at risk of loss or damage due to climate change are often also at risk from other social and political factors, such as war, land use and agricultural practices, and tourism.
Africa
Sea level rise and coastal erosion are causing loss of structures and archaeological material in the historic port city of Kilwa Kisiwani. Portions of some monuments are already underwater. Mitigation strategies under development include engineered structures (gabions) to minimise the effect of wave action.
Americas
Chan Chan archeological site, Peru
The ancient city site of Chan Chan has experienced both more extreme rainfall and periods of drought, due to El Nino weather patterns. This area has always experienced extreme weather events, but the frequency of events is increasing. Rising groundwater is destabilising building foundations. Mitigation has included strategies to control the rising water table, stabilisation of perimeter walls, architectural documentation, local skills development and awareness-building campaigns, and a disaster preparedness plan.
Ivvavik /Vuntut/Herschel Island (Qikiqtaruk), Canada
Due to decrease of sea areas and higher exposure to storms, the 19th century whalers' settlement of Hershel Island had to be relocated inland to keep the buildings dry and avoid flooding of low lying structures. If coastal erosion continues another relocation might be needed and lead to the abandonment of some structures. The deterioration of the permafrost compromises graves structures and leads to buried caskets tumbling and breakage. (Case studies on climate change and World Heritage, Unesco)
Asia Pacific
Mosque City of Bagerhat, Bangladesh
Building structures in the Mosque City of Bagerhat are decaying due to rising water and soil salinity. Salt crystals that become embedded in the rock expand in the presence of moisture and hasten the disintegration and weathering of stone buildings.
Rapa Nui, Polynesia
Also known as Easter Island, Rapa Nui has been a World Heritage Site since 1995. The stone statues on Rapa Nui are threatened by sea level rises and coastal damage from storms. An increase in ocean swells and wave heights causes undercutting and erosion of rock faces and loss of archaeological remains.
Europe
Coastal Great Britain
Increased coastal erosion and rising sea levels threaten several historic castles in Great Britain, including Hurst Castle in Hampshire, Tintagel in Cornwall, Piel Castle in Cumbria, Bayard's Cove Fort in Devon, Garrison Walls in the Isles of Scilly and Calshot Castle in Southampton. According to site managers English Heritage, it will be necessary to repair walls and improve defences against storms to prevent further damage.
Edinburgh, Scotland
Increased rainfall and extreme weather events are also increasing the risk of flooding and slope instability in the old city of Edinburgh. Annual rainfall has increased 13% since 1970. Increased wetting and drying is eroding the sandstone used to build Edinburgh Castle and eroding the volcanic rock on which it is built.
Venice, Italy
Rising sea water and inundation threaten the city of Venice and its lagoon.
References
Materials degradation
Climate change and society
Cultural heritage
Effects of climate change | Cultural heritage at risk from climate change | [
"Materials_science",
"Engineering"
] | 729 | [
"Materials degradation",
"Materials science"
] |
69,224,554 | https://en.wikipedia.org/wiki/NanoDragon | NanoDragon is a 3U CubeSat built by the Vietnam National Satellite Center (VNSC). NanoDragon will use its automatic identification system (AIS) receiver to monitor vessels, and will also test the accuracy of its attitude control using an optical imager. It carries an advanced OBC (on board computer) developed by Japan's Meisei Electric.
Although NanoDragon was successfully launched, the ground stations unable to contact with the satellite.
See also
PicoDragon
MicroDragon
References
Satellites of Vietnam
Spacecraft launched in 2021 | NanoDragon | [
"Astronomy"
] | 113 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
69,224,614 | https://en.wikipedia.org/wiki/Hazardous%20substances%20in%20cultural%20heritage%20collections | Cultural heritage collections contain many materials known to be hazardous to the environment and to human health. Some hazardous substances may be an integral part of the object (such as a toxic paint pigment or a naturally radioactive mineral sample), applied as a treatment after the object was made (such as a pesticide) or the result of material degradation (such as the exudation of plasticiser from polyvinyl chloride). The toxicity of such objects in heritage collections can also determine their historic and scientific value. Consequently, management of these materials within collecting organisations can be complex in terms of health and safety.
These substances represent a hazard for people working with or using affected collections items as well as acting as a record of the use of these materials over time. Disposal or removal of hazardous substances from cultural collections can be expensive and logistically challenging.
Many of the hazardous substances found in cultural heritage collections may also be classified as Dangerous Goods or Scheduled Poisons and subject to strict regulations concerning their sale, storage, labelling, handling, transport, display and disposal.
Asbestos
Asbestos was used widely as a fire-proof or fire-suppressing agent, in scientific, industrial and domestic appliances, clothing, and tools. Asbestos can also be found mixed with cements and resins and woven into fabrics. Asbestos-containing mineral samples may be present in natural history collections. The safe management of asbestos is highly regulated in most countries, e.g. the UK Control of Asbestos Regulations 2012.
Corrosives
Acids and alkalis can be found in industrial chemicals (e.g. photographic developing agents), as the preservative used for fluid-preserved natural history specimens (formalin) and in batteries.
Heavy metals (lead, mercury, arsenic, etc.)
Lead is a soft, malleable metal that has been used for a variety of purposes throughout history: as food additives, paint pigments, or solder, and to make pewter drinking vessels and lead toys.
Mercury can be found in scientific equipment such as thermometers, and as a residue on animal skins, furs, and hats where it was used in the preparation process. Mercuric chloride was also used as a pesticide or biocide.
Arsenic and mercury are a common hazardous substance found in historic dress and textile collections from the 18th and 19th centuries as it was used in textile dyes e.g. Scheele’s Green a yellow-green pigment, and textile manufacture, hat making.
Mould and micro-organisms
Mould and micro-organisms (e.g. bacteria) may be present on the surface of collection objects, particularly those that have been stored in warm and damp conditions.
Paints, pigments and dyes
Many toxic pigments and other paint ingredients have been used, many since antiquity. Toxic pigments include lead, mercury, cadmium, cobalt, antimony and arsenic.
Pesticides and herbicides
Museum collections can contain samples of actual pesticides and herbicides (such as mercuric chloride, paradichlorobenzene and DDT) as well as artefacts that have been treated with pesticides to prevent infestations by museum personnel and field collectors especially over the 18th century to the end of the 20th century as "[…] such treatments were traditionally thought to be part of general collections maintenance."
The latter can prevent access to collection items unless the chemical residues can be removed or safely managed, as there are also human health implications associated with most pesticides.
Once a commonplace treatment for objects made of organic materials (e.g. animal and insect specimens, woollen clothing, objects containing plant fibres, fur and feathers), use of pesticides has substantially diminished with the development of integrated pest management as a collection management strategy.
Naphthalene is one of the most commonly encountered pesticide residues found on museum collections. As a volatile substance, it can sublimate and recrystallise on surfaces nearby.
Mercury-based pesticides (such as mercuric chloride) can release mercury vapour, which can contaminate other collection objects and surfaces nearby. Monitoring vapour levels has shown that venting closed storage cabinets before use lowers airborne concentration limits to safe limits. Other mitigation strategies include enclosing affected collection objects inside enclosures made from gas vapour barriers and using vented cabinets instead of sealed cabinets for storage.
Plastics and plasticisers
Some deteriorating plastics may generate acidic byproducts (such as acetic acid from cellulose acetate film or nitric acid from cellulose nitrate film), which pose risk to those handling affected objects. Others leach plasticisers, such as the phthalates released from polyvinyl chloride or biphenyl A (BPA).
Pharmaceuticals, poisons and drugs
Many museums contain collections of old medicines and poisons, containing substances which - though once intended to heal - may contains substances hazardous to humans and to the environment. For these reasons pharmacy and prescription-only medicines in museum collections may be subject to local regulations for storage and display.
Radiation
Radioactive minerals may be found in mineralogy, palaeontology, and maritime collections, in radioactive paints on watch faces and aircraft dials, in medical and analytical equipment. Radiation in museum collections must usually be strictly controlled in accordance with local regulations.
Solvents and chemicals
A variety of chemicals can be found in cultural heritage collections, including oxidising agents, flammable and combustible liquids, and other solvents with known toxic, carcinogenic or other health effects. Ethanol and formalin are used to preserve specimens in natural history collections. Petroleum products may be found in industrial heritage collections. Organic solvents may also be found within cosmetics, medicines, and photographic processing chemicals.
Zoonotics
Zoonotic diseases (those transmitted from animals to humans) may be present in natural history specimens or museum objects made with unprocessed animal products.
Further reading
Profiling Hazardous Substances in the Museum Victoria State Collection
References
Hazardous materials
Cultural heritage conservation | Hazardous substances in cultural heritage collections | [
"Physics",
"Chemistry",
"Technology"
] | 1,215 | [
"Materials",
"Hazardous materials",
"Matter"
] |
69,224,766 | https://en.wikipedia.org/wiki/Gliese%20569 | Gliese 569 is a ternary star system composed of a main-sequence star orbited by a pair of brown dwarfs in the constellation of Boötes about away.
System
The primary star GJ 569A is orbited by the much fainter (3.7 magnitudes) secondary GJ 659B at a projected separation of , discovered in 1988. The star GJ 569B (BD+16 2708B) itself is a close binary system of two high-mass brown dwarfs in a 2.4-year orbit, and a small (0.538) magnitude difference between components. The orbital plane of close binary GJ 569Ba and GJ 569Bb is expected to precess at timescales of about 100 thousand years due to the gravitational influence of GJ 569A.
Properties
The primary star Gliese 569A is a flare star. The star was given its variable star designation, CE Boötis, in 1975. The nature of the brown dwarf binary Gliese 569B is highly uncertain, and it was even suspected Gliese 569Ba itself may be either a low-mass star or a binary object. But with a mass about 8-9% that of the Sun means it may possibly be a binary of two extremely low mass ultra-cool dwarf stars that are extremely dim, dim enough to look like a brown dwarf. Both brown dwarfs are weakly variable, likely due to starspot activity.
References
Triple star systems
Boötes
072944
J14542923+1606039
BD+16 2708
0569
Bootis, CE
M-type main-sequence stars
Brown dwarfs
Flare stars | Gliese 569 | [
"Astronomy"
] | 346 | [
"Boötes",
"Constellations"
] |
69,226,402 | https://en.wikipedia.org/wiki/Julius%20Oscar%20Hinze | Julius Oscar Hinze (J. O. Hinze in most of his publications, 1907–1993) was a Dutch scientist specialized in fluid dynamics. He was the author of the textbook Turbulence (1959; 1975; US: McGraw-Hill). Throughout his career, he mostly stayed in Delft University of Technology.
The term Hinze scale (sometimes Kolmogorov-Hinze scale) in turbulence research is named after him.
Publications
In chronological order:
Die Erzeugung von Ringwellen auf einer Flüssigkeitsoberfläche durch periodisch wirkende Druckkräfte (1936)
Atomization of Liquids by Means of a Rotating Cup (1950)
Fundamentals of the hydrodynamic mechanism of splitting in dispersion processes (1955)
The Effect of Compressibility on the Turbulent Transport of Heat in a Stably Stratified Atmosphere (1959)
Turbulence (with M. S. Uberoi, 1960)
On the hydrodynamics of turbidity currents (1960)
Secondary Currents in Wall Turbulence (1967)
Fine-structure turbulence in the wall region of a turbulent boundary layer (1975)
Memory effects in turbulence (1975)
Rotation of the Reynolds' stress tensor in a decaying grid-generated turbulent flow (with P. J. H. Builtjes, 1977)
References
External links
1907 births
1993 deaths
Fluid dynamicists
20th-century Dutch mathematicians
20th-century Dutch physicists | Julius Oscar Hinze | [
"Chemistry"
] | 299 | [
"Fluid dynamicists",
"Fluid dynamics"
] |
69,226,536 | https://en.wikipedia.org/wiki/Albert%20Alan%20Townsend | Albert Alan Townsend FRS (22 Jan 1917 – 31 Aug 2010) was an Australian scientist specialized in fluid dynamics. He was the author of the textbook The Structure of Turbulent Shear Flow (1956; 1976; Cambridge University Press). The terms Townsend's eddies(or Townsend's wall-attached eddies), Batchelor–Howells–Townsend spectrum and Townsend–Perry constants in turbulence research are named after him. His PhD advisor was G. I. Taylor and he was a close collaborator of George Batchelor.
He was a Fellow of the Royal Society (1960).
Graduated from Canberra University and Melbourne University, he started his physicist career with in the field of nuclear physics. In 1938, he went to the University of Cambridge and joined the Cavendish Laboratory for a PhD degree (at that time, there were no Australian universities offering PhD degree).
During the Second World War, he joined military research and worked on aerodynamics in Australia. In this period, he met George Batchelor and started to research in fluid dynamics. After getting back to Cambridge, he and Batchelor studied under Geoffrey Ingram Taylor. He obtained PhD in 1947 and the thesis title was Beta Ray Spectra of Light Elements and Turbulent Flow.
Townsend remained in the Cavendish Laboratory for the rest of his career.
Outside work, he married Valeria Dees(?–2002) in 1950 and they had three children. He was an enthusiastic tennis player.
Publications
Selective Absorption of Neutrons in Silver (1936, co-authored with Eric Henry Stonely Burhop and R. D. Hill)
The production of gamma-rays by neutrons (1938, co-authored with Eric Henry Stonely Burhop and R. D. Hill)
Intensity of γ radiation produced by slow neutrons (1938, co-authored with R. D. Hill)
The β-ray spectrum of Ra E (1939, co-authored with Leslie Harold Martin)
β-ray spectra of light elements (1941)
'Singing'-Corner Vanes (1945, co-authored with George Batchelor)
The measurement of double and triple correlation derivatives in isotropic turbulence (1947)
Measurements in the turbulent wake of a cylinder (1947)
Decay of vorticity in isotropic turbulence (1947, co-authored with George Batchelor)
Experimental evidence for the theory of local isotropy (1948, co-authored with George Batchelor)
Decay of isotropic turbulence in the initial period (1948, co-authored with George Batchelor)
Decay of turbulence in the final period (1948, co-authored with George Batchelor)
Momentum and energy diffusion in the turbulent wake of a cylinder (1949)
The fully developed wake of a circular cylinder (1949)
The nature of turbulent motion at large wave-numbers (1949, co-authored with George Batchelor)
The diffusion of heat spots in isotropic turbulence (1951)
The passage of turbulence through wire gauzes (1951)
Similarity and self-preservation in isotropic turbulence (1951, co-authored with Robert William Stewart)
The structure of the turbulent boundary layer (1951)
On the fine-scale structure of turbulence (1951)
The diffusion behind a line source in homogeneous turbulence (1954)
The uniform distortion of homogeneous turbulence (1954)
The properties of equilibrium boundary layers (1956)
Turbulent convection over a heated horizontal surface (1957, co-authored with D. B. Thomas)
Turbulent flow in a stably stratified atmosphere (1958)
The effects of radiative transfer on turbulent flow of a stratified fluid (1958)
The turbulent boundary layer (1958)
Small-scale variation of convected quantities like temperature in turbulent fluid Part 2. The case of large conductivity (1959, co-authored with George Batchelor and I. D. Howells)
Temperature fluctuations over a heated horizontal surface (1959)
The development of turbulent boundary layers with negligible wall stress (1960)
A continuum theory of the isothermal flow of liquid helium II (1961)
On the fine-scale structure of turbulence (1961)
Natural convection in the earth's boundary layer (1962)
The behaviour of a turbulent boundary layer near separation (1962)
On the hydrodynamic equations for flow of liquid helium II with mutual friction (1963)
Natural convection in water over an ice surface (1964)
Change of terrain roughness and the wind profile (1964, co-authored with H. A . Panofsky)
The interpretation of stellar shadow-bands as a consequence of turbulent mixing (1965)
Self-preserving flow inside a turbulent boundary layer (1965)
Self-preserving development within turbulent boundary layers in strong adverse pressure gradients (1965)
The response of a turbulent boundary layer to abrupt changes in surface conditions (1965)
Excitation of internal waves by a turbulent boundary layer (1965)
The flow in a turbulent boundary layer after a change in surface roughness (1966)
Internal waves produced by a convective layer (1966)
The mechanism of entrainment in free turbulent flows (1966)
Wind and the formation of inversions (1967)
Excitation of internal waves in a stably-stratified atmosphere with considerable wind-shear (1968)
Entrainment and the structure of turbulent flow (1970)
Mixed convection over a heated horizontal plane (1972)
Flow in a deep turbulent boundary layer over a surface distorted by water waves (1972)
Flow patterns of large eddies in a wake and in a boundary layer (1979)
The response of sheared turbulence to additional distortion (1980)
Identification of flow patterns in turbulent flows (1980, co-authored with J. C. Mumford and A. M. Savill)
The development of a turbulent wake in a distorting duct (1981, co-authored with C. J. Elliott)
Turbulent Couette flow between concentric cylinders at large Taylor numbers (1982, co-authored with G. P. Smith)
Turbulent Flow and the Effects of Curvature (1983)
Axisymmetric Couette flow at large Taylor numbers (1984)
Organized eddy structures in turbulent flows (1987)
Entrainment in Free Turbulent Flows (1989)
Organised Eddies in Turbulent Shear Flows (1993)
References
04 November 2010, The Times https://www.thetimes.co.uk/article/alan-townsend-9txhxvfz3wf, retrieved on 9 November 2021 (subscription required)
Ivan Marusic and Timothy B. Nickels (2011), A Voyage Through Turbulence (Davidson P.A., Kaneda Y., Moffatt K., Sreenivasan K.R. (eds.), ), p. 305–328
External links
Photo of Albert Townsend
Fluid dynamicists
1917 births
2010 deaths
20th-century Australian physicists
21st-century Australian physicists
Alumni of the University of Cambridge | Albert Alan Townsend | [
"Chemistry"
] | 1,390 | [
"Fluid dynamicists",
"Fluid dynamics"
] |
69,226,647 | https://en.wikipedia.org/wiki/Mercedes-Benz%20M153%20engine | The Mercedes-Benz M153 engine is a naturally-aspirated, 2.3-liter, straight-6, internal combustion piston engine, designed, developed and produced by Mercedes-Benz; between 1938 and 1943.
Engine
The engine was derived from the existing unit, but the cylinder bore was increased by one millimeter which gave rise to an overall increase in engine size to 2289cc. Despite the slightly larger engine size and the inclusion of two twin-chamber Solex 30 JFFK carburetors, claimed power was unchanged at 55 PS (40 kW): the compression ratio was set at the relatively low value of 1 : 6.6. Claimed top speed was 116 km/h (72 mph).
Applications
Mercedes-Benz W153
References
Mercedes-Benz engines
Straight-six engines
Engines by model
Gasoline engines by model | Mercedes-Benz M153 engine | [
"Technology"
] | 172 | [
"Engines",
"Engines by model"
] |
69,227,378 | https://en.wikipedia.org/wiki/Mercedes-Benz%20M142%20engine | The Mercedes-Benz M142 engine is a naturally-aspirated, 3.2-liter to 3.4-liter, straight-6, internal combustion piston engine, designed, developed and produced by Mercedes-Benz; between 1937 and 1942.
Applications
Mercedes-Benz W142
Mercedes-Benz 320A
References
Mercedes-Benz engines
Straight-six engines
Engines by model
Gasoline engines by model | Mercedes-Benz M142 engine | [
"Technology"
] | 81 | [
"Engines",
"Engines by model"
] |
69,227,444 | https://en.wikipedia.org/wiki/Mercedes-Benz%20M143%20engine | The Mercedes-Benz M143 engine is a naturally-aspirated, 2.2-liter, straight-6, internal combustion piston engine, designed, developed and produced by Mercedes-Benz; between 1936 and 1941.
Applications
Mercedes-Benz W143
References
Mercedes-Benz engines
Straight-six engines
Engines by model
Gasoline engines by model | Mercedes-Benz M143 engine | [
"Technology"
] | 70 | [
"Engines",
"Engines by model"
] |
69,227,698 | https://en.wikipedia.org/wiki/Totally%20implantable%20cochlear%20implant | A totally implantable cochlear implant (TICI) is a new type of cochlear implant and is currently in development. Unlike a conventional cochlear implant, which has both an internal component (the implant) and an external component (the audio processor), all the components of the TICI - including the microphone and battery - are implanted under the skin. This makes the TICI completely invisible from the outside.
The TICI is currently in the clinical feasibility study stage of development. The first patient in Europe was implanted with a TICI in September 2020 as part of a clinical trial.
Parts
The TICI contains the same internal components as a conventional cochlear implant: the magnet, antenna coil, electronics and the electrode array, however will also include the features of an audio processor including an implanted rechargeable battery and microphone. The TICI components may be integrated into a single case, the so-called monobody design, or the various components may be attached to one another by connectors, thereby allowing replacement of each of the several modules in case of failure.
Some external hardware will still be required. The internal battery is charged transcutaneously using an external charger, for example while the user sleeps at night. A remote control or app may also be needed in order to switch the implant on and off, adjust the microphone sensitivity and indicate the battery status, among other functions.
Benefits
A totally implantable — and therefore “invisible” — cochlear implant is seen as a benefit to users, particularly those who feel self-conscious about wearing visible hearing devices.
In addition, as the TICI has no external components, it is less susceptible to small breakages from knocks and falls. The lack of external parts also means that they cannot be mislaid – a common problem with pediatric users.
A TICI can function while showering, swimming, and during many types of vigorous physical activity. This allows the user to hear while carrying out these activities.
References
Biomedical engineering
Medical devices | Totally implantable cochlear implant | [
"Engineering",
"Biology"
] | 414 | [
"Biological engineering",
"Medical technology",
"Medical devices",
"Biomedical engineering"
] |
69,227,791 | https://en.wikipedia.org/wiki/Relational%20mobility | Relational mobility is a sociological variable that represents how much freedom individuals have to choose which persons to have relationships with, including friendships, working relationships, and romantic partnerships in a given society. Societies with low relational mobility have less flexible interpersonal networks. People form relationships based on circumstance rather than active choice. In these societies, relationships are more stable and guaranteed, while there are fewer opportunities to leave unsatisfying relationships and find new ones.
Group memberships tend to be fixed, and individuals have less freedom to select or change these relationships even if they wished to.
In contrast, societies with high relational mobility give people choice and freedom to select or leave interpersonal relationships based on their personal preferences. Such relationships are based on mutual agreement and are not guaranteed to last.
Individuals have many opportunities to meet new people and to choose whom they interact with or which groups they belong to in such societies.
Relational mobility is conceived as a socioecological factor, which means that it depends on the social and natural environment. The theory of relational mobility has attracted increased interest since the early 2000's because it has been found to explain important cross-cultural differences in people's behavior and way of thinking.
The relational mobility scale
The relational mobility scale is a sociometric scale used for measuring relational mobility in population surveys. This scale is based on a series of questions asking people not about their own situation, but the situation of people around them such as friendship groups, hobby groups, sports teams, and companies. The questions are probing to what degree these people are able to choose the people whom they interact with in their daily life, according to their own preferences.
Geographic differences
Relational mobility is low in cultures with subsistence styles that put people in tight relationships with reciprocal duties such as farming that requires coordination of labor. The growing of paddy rice, in particular, requires tight coordination of labor and irrigation. The lowest level of relational mobility is found in East Asian countries where rice farming is a prevailing means of subsistence. A comparative study has found significant differences in ways of thinking between areas in China dominated by rice farming and areas dominated by wheat farming. This difference could not be explained well by other theories.
On the opposite side of the spectrum is nomadic herding. Herders move frequently, meaning that they have fewer stable, long-term relationships and more opportunities to form and break relationships. Studies have shown that herding cultures emphasize more individual decision making while nearby farming and fishing cultures emphasize harmonious social interdependence and holistic thinking.
A large cross-cultural study has found that relational mobility is lowest in East Asian countries where rice farming is common. The relational mobility is higher in industrialized European countries and English-speaking countries, while it is highest in South American countries. This study found a strong correlation between relational mobility and subsistence style, and a somewhat weaker correlation with environmental threats that require group cohesion and cooperation.
Consequences for people's behavior and way of thinking
People in cultures with low relational mobility are careful to avoid conflicts and disagreements in order to maintain harmony in the social groups that they cannot escape. They are careful not to offend others in order to avoid a bad reputation. Thus, the cultural preference for conformity, which is common in East Asian cultures, is actually a strategy to avoid bad reputation and social exclusion.
People in these cultures are more sensitive to social rejection
and more likely to feel ashamed towards their friends (but not towards strangers) in order to mitigate information that may damage their reputation.
The degree of relational mobility is influencing people's way of thinking. A low relational mobility is leading to cognitive tendencies that theorists call holistic thinking, while high relational mobility is associated with analytic thinking.
This difference in social cognition is defined as a difference in how people attribute their own and others’ behavior to either internal causes (the actors’ dispositions) or external causes (situational factors).
Individuals’ need to coordinate their actions and avoid conflict makes salient the influence of external forces, including powerful others in the environment, on their own situation.
An external locus of control is typical of cultures with low relational mobility. People pay more attention to situational factors and to chance, fate, and luck than to individual dispositions in these cultures.
In contrast, high relational mobility is associated with an internal locus of control with more focus on the individual and less focus on the social environment.
Social relationships and group memberships are more easily formed and terminated in cultures with high relational mobility. Interpersonal connections are here based on mutual convenience and thus less stable and reliable.
Less importance is placed on job security, while also divorce is more common and more accepted.
People invest more effort in attracting, forming, and maintaining social bonds where relationships cannot be taken for granted. People exhibit more self-enhancement behavior and higher self-esteem here in order to advertise their value as companions and to facilitate the forming of social bonds.
People are more prone to develop personal uniqueness in high relational mobility societies in order to increase their value in the market-like competition for social relationships. Idiosyncratic behavior is less common in low relational mobility societies where it may lead to ostracism.
People tend to invest more in maintaining friendships as well as romantic partnerships where relational mobility is high, because the stability of the bond cannot be taken for granted. This bonding behavior includes helping, intimacy, passion, and gift-giving.
People even disclose personal information to friends in order to show their commitment to the relationship.
There are different ways of dealing with uncertainty about the quality of a potential partner or collaborator. In low relational mobility societies such as Japan, firms often maintain long-term relations with loyal partners even if better deals with new partners could be obtained. Business strategies tend to be different in societies with higher relational mobility, such as North America, where new relationships are formed based on trust. There is higher risk in new business relationships, but also more to gain by finding a potentially better business partner than one already has.
In general, the level of interpersonal trust has been found to be higher in societies with high relational mobility, not only in business relations, but also in general interpersonal relations and on social media.
Consequences for societies
Researchers have found evidence that cultures with higher relational mobility had higher rates of COVID-19 infections and death per capita. The theory is that cultures with higher relational mobility have more interactions in broad social networks and with new people, and these interactions give the virus more opportunities to spread. Cultural differences in relational mobility predicted more infections and death, even controlling for differences in economic development, international trade, population density, the prevalence of COVID-19 testing, and other variables. There is some evidence that relational mobility was particularly important in the first few months of the pandemic, but it became less important over time, perhaps because cultures shut down public venues, and people changed their socialization patterns.
However, there seem to be exceptions to this pattern. For example, cultures with low relational mobility may have stronger expectations of seeing family and friends for important holidays. This could explain why a study in China found that rice-farming areas had rates of COVID-19 infections that were three times higher than wheat-farming areas at the beginning of the outbreak in 2020, which coincided with Chinese New Year. People in rice-farming areas of China reported visiting more family and friends than people in wheat-farming areas of China for Chinese New Year. In contrast, people in cultures of high relational mobility may give people more flexibility to choose whether or not to see people for holidays.
Animal analogies
The theory of relational mobility has analogies in the mating behavior, cooperation behavior, and inter-species symbiosis among animals. It has been observed that such behavior is adjusted to the stability of the relationships, the degree of competition on the relationship "market", and the possibilities for cheating among a variety of species, including birds and insects.
See also
Costly signaling theory in evolutionary psychology
Cross-cultural psychology
Cross-cultural studies
Cultural psychology
East Asian cultural sphere
Locus of control
Long-term vs, Short-term orientation
Socioecology
Socio-ecological system
External links
Relational mobility website
References
Behavioral concepts
Cognition
Cognitive science
Interpersonal relationships
Social psychology | Relational mobility | [
"Biology"
] | 1,647 | [
"Behavior",
"Behavioral concepts",
"Behaviorism",
"Interpersonal relationships",
"Human behavior"
] |
69,228,425 | https://en.wikipedia.org/wiki/Grand%20Antique%20marble | Grand Antique marble (also Celtic marble (), Grand Antique of Aubert, and known in Roman times as Marmor Aquitanicum), is a prestigious marble, composed of clasts of black limestone and white calcite, quarried near Aubert-Moulis in France. The fault breccia from which it is extracted was formed at the end of the Cretaceous period, following the corrugation that affected the Northern Pyrenean area about 65 million years ago.
The marble was first quarried by the Romans in the third or fourth century and was exported in large quantities to Rome and Constantinople, primarily for decorative columns. Roman examples include the ciborium in Santa Cecilia and the candelabra of the Paschal candle in Santa Maria Maggiore. In Byzantium, the marble was used for decorative panels in Hagia Sophia.
The quarry was subsequently closed, and the blocks already extracted were utilized for several churches, including St Peter's Basilica in Rome, St Mark's Basilica in Venice, and Westminster in London. The marble was widely used by Émile-Jacques Ruhlmann for fireplaces. Examples are also found in the Les Invalides, for the columns on the altar in the chapel and the tomb of Joseph Napoleon, and at Versailles. More recently, this marble had also been extensively used in New York during the 1920s on the exterior facade of the Roosevelt Hotel, as well as on the recent extension of the Museum of Modern Art for interior decoration.
Exploited intermittently and then closed in 1948, the quarry was reopened in 2012 when the Italian company Escavamar purchased the operating rights with the goal of providing high-quality marble in measured quantities to a luxury and high-end clientele. In 2015, Escavamar officially registered the trademark "Grand Antique d'Aubert".
References
Building materials
Types of marble
Hagia Sophia | Grand Antique marble | [
"Physics",
"Engineering"
] | 387 | [
"Building engineering",
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69,228,969 | https://en.wikipedia.org/wiki/Joe%20Caserta | Joe Caserta is an American information specialist and author. He is best known as the founder and president of data and analytics consulting, architecture, and implementation firm Caserta founded in 2001. Management consulting firm McKinsey & Company acquired Caserta on June 1, 2022.
Joe Caserta was born and raised in New York. He studied database application development and design at Columbia University. He is a data science expert, keynote speaker, and panelist.
Working with Ralph Kimball, he co-authored The Data Warehouse ETL Toolkit, (Wiley, 2004) which is used as a textbook for courses teaching ETL processes in data warehousing.
Caserta is the founder and host of the Big Data Warehousing Meetup group in New York, which has more than 5,000 members.
References
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Joe Caserta on SiliconANGLE, TheCUBE (July 18, 2018)
IBM Big Data & Analytics Hub interview of Joe Caserta (August 25, 2016)
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Business intelligence
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Spokespersons | Joe Caserta | [
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"People in information technology",
"Information technology"
] |
56,541,610 | https://en.wikipedia.org/wiki/Viscosity%20models%20for%20mixtures | The shear viscosity (or viscosity, in short) of a fluid is a material property that describes the friction between internal neighboring fluid surfaces (or sheets) flowing with different fluid velocities. This friction is the effect of (linear) momentum exchange caused by molecules with sufficient energy to move (or "to jump") between these fluid sheets due to fluctuations in their motion. The viscosity is not a material constant, but a material property that depends on temperature, pressure, fluid mixture composition, local velocity variations. This functional relationship is described by a mathematical viscosity model called a constitutive equation which is usually far more complex than the defining equation of shear viscosity. One such complicating feature is the relation between the viscosity model for a pure fluid and the model for a fluid mixture which is called mixing rules. When scientists and engineers use new arguments or theories to develop a new viscosity model, instead of improving the reigning model, it may lead to the first model in a new class of models. This article will display one or two representative models for different classes of viscosity models, and these classes are:
Elementary kinetic theory and simple empirical models - viscosity for dilute gas with nearly spherical molecules
Power series - simplest approach after dilute gas
Equation of state analogy between PVT and TP
Corresponding state model - scaling a variable with its value at the critical point
Friction force theory - internal sliding surface analogy to a sliding box on an inclined surface
Multi- and one-parameter version of friction force theory
Transition state analogy - molecular energy needed to squeeze into a vacancy analogous to molecules locking into each other in a chemical reaction
Free volume theory - molecular energy needed to jump into a vacant position in the neighboring surface
Significant structure theory - based on Eyring's concept of liquid as a blend of solid-like and gas-like behavior / features
Selected contributions from these development directions is displayed in the following sections. This means that some known contributions of research and development directions are not included. For example, is the group contribution method applied to a shear viscosity model not displayed. Even though it is an important method, it is thought to be a method for parameterization of a selected viscosity model, rather than a viscosity model in itself.
The microscopic or molecular origin of fluids means that transport coefficients like viscosity can be calculated by time correlations which are valid for both gases and liquids, but it is computer intensive calculations. Another approach is the Boltzmann equation which describes the statistical behaviour of a thermodynamic system not in a state of equilibrium. It can be used to determine how physical quantities change, such as heat energy and momentum, when a fluid is in transport, but it is computer intensive simulations.
From Boltzmann's equation one may also analytically derive (analytical) mathematical models for properties characteristic to fluids such as viscosity, thermal conductivity, and electrical conductivity (by treating the charge carriers in a material as a gas). See also convection–diffusion equation. The mathematics is so complicated for polar and non-spherical molecules that it is very difficult to get practical models for viscosity. The purely theoretical approach will therefore be left out for the rest of this article, except for some visits related to dilute gas and significant structure theory.
Use, definition and dependence
The classic Navier-Stokes equation is the balance equation for momentum density for an isotropic, compressional and viscous fluid that is used in fluid mechanics in general and fluid dynamics in particular:
On the right hand side is (the divergence of) the total stress tensor which consists of a pressure tensor and a dissipative (or viscous or deviatoric) stress tensor . The dissipative stress consists of a compression stress tensor (term no. 2) and a shear stress tensor (term no. 3). The rightmost term is the gravitational force which is the body force contribution, and is the mass density, and is the fluid velocity.
For fluids, the spatial or Eularian form of the governing equations is preferred to the material or Lagrangian form, and the concept of velocity gradient is preferred to the equivalent concept of strain rate tensor. Stokes assumptions for a wide class of fluids therefore says that for an isotropic fluid the compression and shear stresses are proportional to their velocity gradients, and respectively, and named this class of fluids for Newtonian fluids. The classic defining equation for volume viscosity and shear viscosity are respectively:
The classic compression velocity "gradient" is a diagonal tensor that describes a compressing (alt. expanding) flow or attenuating sound waves:
The classic Cauchy shear velocity gradient, is a symmetric and traceless tensor that describes a pure shear flow (where pure means excluding normal outflow which in mathematical terms means a traceless matrix) around e.g. a wing, propeller, ship hull or in e.g. a river, pipe or vein with or without bends and boundary skin:
where the symmetric gradient matrix with non-zero trace is
How much the volume viscosity contributes to the flow characteristics in e.g. a choked flow such as convergent-divergent nozzle or valve flow is not well known, but the shear viscosity is by far the most utilized viscosity coefficient. The volume viscosity will now be abandoned, and the rest of the article will focus on the shear viscosity.
Another application of shear viscosity models is Darcy's law for multiphase flow.
where a = water, oil, gas
and and are absolute and relative permeability, respectively. These 3 (vector) equations models flow of water, oil and natural gas in subsurface oil and gas reservoirs in porous rocks. Although the pressures changes are big, the fluid phases will flow slowly through the reservoir due to the flow restriction caused by the porous rock.
The above definition is based on a shear-driven fluid motion that in its most general form is modelled by a shear stress tensor and a velocity gradient tensor. The fluid dynamics of a shear flow is, however, very well illustrated by the simple Couette flow. In this experimental layout, the shear stress and the shear velocity gradient (where now ) takes the simple form:
Inserting these simplifications gives us a defining equation that can be used to interpret experimental measurements:
where is the area of the moving plate and the stagnant plate, is the spatial coordinate normal to the plates. In this experimental setup, value for the force is first selected. Then a maximum velocity is measured, and finally both values are entered in the equation to calculate viscosity. This gives one value for the viscosity of the selected fluid. If another value of the force is selected, another maximum velocity will be measured. This will result in another viscosity value if the fluid is a non-Newtonian fluid such as paint, but it will give the same viscosity value for a Newtonian fluid such as water, petroleum oil or gas. If another parameter like temperature, , is changed, and the experiment is repeated with the same force, a new value for viscosity will be the calculated, for both non-Newtonian and Newtonian fluids. The great majority of material properties varies as a function of temperature, and this goes for viscosity also. The viscosity is also a function of pressure and, of course, the material itself. For a fluid mixture, this means that the shear viscosity will also vary according to the fluid composition. To map the viscosity as a function of all these variables require a large sequence of experiments that generates an even larger set of numbers called measured data, observed data or observations. Prior to, or at the same time as, the experiments is a material property model (or short material model) proposed to describe or explain the observations. This mathematical model is called the constitutive equation for shear viscosity. It is usually an explicit function that contains some empirical parameters that is adjusted in order to match the observations as good as the mathematical function is capable to do.
For a Newtonian fluid, the constitutive equation for shear viscosity is generally a function of temperature, pressure, fluid composition:
where is the liquid phase composition with molfraction for fluid component i, and and are the gas phase and total fluid compositions, respectively. For a non-Newtonian fluid (in the sense of a generalized Newtonian fluid), the constitutive equation for shear viscosity is also a function of the shear velocity gradient:
The existence of the velocity gradient in the functional relationship for non-Newtonian fluids says that viscosity is generally not an equation of state, so the term constitutional equation will in general be used for viscosity equations (or functions). The free variables in the two equations above, also indicates that specific constitutive equations for shear viscosity will be quite different from the simple defining equation for shear viscosity that is shown further up. The rest of this article will show that this is certainly true. Non-Newtonian fluids will therefore be abandoned, and the rest of this article will focus on Newtonian fluids.
Dilute gas limit and scaled variables
Elementary kinetic theory
In textbooks on elementary kinetic
theory
one can find results for dilute gas modeling that have widespread use. Derivation of the kinetic model for shear viscosity usually starts by considering a Couette flow where two parallel plates are separated by a gas layer. This non-equilibrium flow is superimposed on a Maxwell–Boltzmann equilibrium distribution of molecular motions.
Let be the collision cross section of one molecule colliding with another. The number density is defined as the number of molecules per (extensive) volume . The collision cross section per volume or collision cross section density is , and it is related to the mean free path by
Combining the kinetic equations for molecular motion with the defining equation of shear viscosity gives the well known equation for shear viscosity for dilute gases:
where
where is the Boltzmann constant, is the Avogadro constant, is the gas constant, is the molar mass and is the molecular mass. The equation above presupposes that the gas density is low (i.e. the pressure is low), hence the subscript zero in the variable . This implies that the kinetic translational energy dominates over rotational and vibrational molecule energies. The viscosity equation displayed above further presupposes that there is only one type of gas molecules, and that the gas molecules are perfect elastic hard core particles of spherical shape. This assumption of particles being like billiard balls with radius , implies that the collision cross section of one molecule can be estimated by
But molecules are not hard particles. For a reasonably spherical molecule the interaction potential is more like the Lennard-Jones potential or even more like the Morse potential. Both have a negative part that attracts the other molecule from distances much longer than the hard core radius, and thus models the van der Waals forces. The positive part models the repulsive forces as the electron clouds of the two molecules overlap. The radius for zero interaction potential is therefore appropriate for estimating (or defining) the collision cross section in kinetic gas theory, and the r-parameter (conf. ) is therefore called kinetic radius. The d-parameter (where ) is called kinetic diameter.
The macroscopic collision cross section is often associated with the critical molar volume , and often without further proof or supporting arguments, by
where is molecular shape parameter that is taken as an empirical tuning parameter, and the pure numerical part is included in order to make the final viscosity formula more suitably for practical use. Inserting this interpretation of , and use of reduced temperature , gives
which implies that the empirical parameter is dimensionless, and that and have the same units. The parameter is a scaling parameter that involves the gas constant and the critical molar volume , and it used to scale the viscosity. In this article the viscosity scaling parameter will frequently be denoted by which involve one or more of the parameters , , in addition to critical temperature and molar mass . Incomplete scaling parameters, such as the parameter above where the gas constant is absorbed into the empirical constant, will often be encountered in practice. In this case the viscosity equation becomes
where the empirical parameter is not dimensionless, and a proposed viscosity model for dense fluid will not be dimensionless if is the common scaling factor. Notice that
Inserting the critical temperature in the equation for dilute viscosity gives
The default values of the parameters and should be fairly universal values, although depends on the unit system. However, the critical molar volume in the scaling parameters and is not easily accessible from experimental measurements, and that is a significant disadvantage. The general equation of state for a real gas is usually written as
where the critical compressibility factor , which reflects the volumetric deviation of the real gases from the ideal gas, is also not easily accessible from laboratory experiments. However, critical pressure and critical temperature are more accessible from measurements. It should be added that critical viscosity is also not readily available from experiments.
Uyehara and Watson (1944) proposed to absorb
a universal average value of (and the gas constant ) into a default value of the tuning parameter as a practical solution of the difficulties of getting experimental values for and/or . The visocity model for a dilute gas is then
By inserting the critical temperature in the formula above, the critical viscosity is calculated as
Based on an average critical compressibility factor of and measured critical viscosity values of 60 different molecule types, Uyehara and Watson (1944) determined an average value of to be
The cubic equation of state (EOS) are very popular equations that are sufficiently accurate for most industrial computations both in vapor-liquid equilibrium and molar volume. Their weakest points are perhaps molar volum in the liquid region and in the critical region.
Accepting the cubic EOS, the molar hard core volume can be calculated from the turning point constraint at the critical point. This gives
where the constant is a universal constant that is specific for the selected variant of the cubic EOS. This says that using , and disregarding fluid component variations of , is in practice equivalent to say that the macroscopic collision cross section is proportional to the hard core molar volume rather than the critical molar volume.
In a fluid mixture like a petroleum gas or oil there are lots of molecule types, and within this mixture there are families of molecule types (i.e. groups of fluid components). The simplest group is the n-alkanes which are long chains of CH2-elements. The more CH2-elements, or carbon atoms, the longer molecule. Critical viscosity and critical thermodynamic properties of n-alkanes therefore show a trend, or functional behaviour, when plotted against molecular mass or number of carbon atoms in the molecule (i.e. carbon number). Parameters in equations for properties like viscosity usually also show such trend behaviour. This means that
This says that the scaling parameter alone is not a true or complete scaling factor unless all fluid components have a fairly similar (and preferably spherical) shape.
The most important result of this kinetic derivation is perhaps not the viscosity formula, but the semi-empirical
parameter that is used extensively throughout the industry and applied science communities as a scaling factor for (shear) viscosity. The literature often reports the reciprocal parameter and denotes it as .
The dilute gas viscosity contribution to the total viscosity
of a fluid will only be important when predicting the viscosity of vapors at low pressures or the viscosity of dense fluids
at high temperatures. The viscosity model for dilute gas, that is shown above, is widely used throughout the industry and applied science communities. Therefore, many researchers do not specify a dilute gas viscosity model when they propose a total viscosity model, but leave it to the user to select and include the dilute gas contribution. Some researchers do not include a separate dilute gas model term, but propose an overall gas viscosity model that cover the entire pressure and temperature range they investigated.
In this section our central macroscopic variables and parameters and their units are temperature [K], pressure [bar], molar mass [g/mol], low density (low pressure or dilute) gas viscosity [μP]. It is, however, common in the industry to use another unit for liquid and high density gas viscosity [cP].
Kinetic theory
From Boltzmann's equation Chapman and Enskog derived a viscosity model for a dilute gas.
where is (the absolute value of) the energy-depth of the potential well (see e.g. Lennard-Jones interaction potential). The term is called the collision integral, and it is occurs as a general function of temperature that the user must specify, and that is not a simple task. This illustrates the situation for the molecular or statistical approach: The (analytical) mathematics gets incredible complex for polar and non-spherical molecules making it very difficult to achieve practical models for viscosity based on a statistical approach. The purely statistical approach will therefore be left out in the rest of this article.
Empirical correlation
Zéberg-Mikkelsen (2001) proposed empirical models for gas viscosity of fairly spherical molecules that is displayed in the section on Friction Force theory and its models for dilute gases and simple light gases. These simple empirical correlations illustrate that empirical methods competes with the statistical approach with respect to gas viscosity models for simple fluids (simple molecules).
Kinetic theory with empirical extension
The gas viscosity model of Chung et alios (1988)
is combination of the Chapman–Enskog(1964)
kinetic theory of viscosity for dilute gases and the empirical expression of
Neufeld et alios (1972)
for the reduced collision integral, but expanded empirical to handle polyatomic, polar and hydrogen
bonding fluids over a wide temperature range. This viscosity model illustrates a successful combination of kinetic theory and empiricism, and it is displayed in the section of Significant structure theory and its model for the gas-like contribution to the total fluid viscosity.
Trend functions and scaling
In the section with models based on elementary kinetic theory, several variants of scaling the viscosity equation was discussed, and they are displayed below for fluid component i, as a service to the reader.
Zéberg-Mikkelsen (2001) proposed an empirical correlation for the parameter for n-alkanes, which is
The critical molar volume of component i is related to the critical mole density and critical mole concentration by the equation . From the above equation for it follows that
where is the compressibility factor for component i, which is often used as an alternative to . By establishing a trend function for the parameter for a homologous series, groups or families of molecules, parameter values for unknown fluid components in the homologous group can be found by interpolation and extrapolation, and parameter values can easily re-generateat at later need. Use of trend functions for parameters of homologous groups of molecules have greatly enhanced the usefulness of viscosity equations (and thermodynamic EOSs) for fluid mixtures such as petroleum gas and oil.
Uyehara and Watson (1944) proposed a correlation for critical viscosity (for fluid component i) for n-alkanes using their average parameter and the classical pressure dominated scaling parameter :
Zéberg-Mikkelsen (2001) proposed an empirical correlation for critical viscosity ηci parameter for n-alkanes, which is
The unit equations for the two constitutive equations above by Zéberg-Mikkelsen (2001) are
Inserting the critical temperature in the three viscosity equations from elementary kinetic theory gives three parameter equations.
The three viscosity equations now coalesce to a single viscosity equation
because a nondimensional scaling is used for the entire viscosity equation. The standard nondimensionality reasoning goes like this: Creating nondimensional variables (with subscript D) by scaling gives
Claiming nondimensionality gives
The collision cross section and the critical molar volume which are both difficult to access experimentally, are avoided or circumvented. On the other hand, the critical viscosity has appeared as a new parameter, and critical viscosity is just as difficult to access experimentally as the other two parameters. Fortunately, the best viscosity equations have become so accurate that they justify calculation in the critical point, especially if the equation is matched to surrounding experimental data points.
Classic mixing rules
Classic mixing rules for gas
Wilke (1950) derived a mixing rule based on kinetic gas theory
The Wilke mixing rule is capable of describing the correct viscosity behavior of gas mixtures showing a nonlinear and non-monotonical behavior, or showing a characteristic bump shape, when the viscosity is plotted versus mass density at critical temperature, for mixtures containing molecules of very different sizes. Due to its complexity, it has not gained widespread use. Instead, the slightly simpler mixing rule proposed by Herning and Zipperer (1936), is found to be suitable for gases of hydrocarbon mixtures.
Classic mixing rules for liquid
The classic Arrhenius (1887). mixing rule for liquid mixtures is
where is the viscosity of the liquid mixture, is the viscosity (equation) for fluid component i when flowing as a pure fluid, and is the molfraction of component i in the liquid mixture.
The Grunberg-Nissan (1949) mixing rule extends the Arrhenius rule to
where are empiric binary interaction coefficients that are special for the Grunberg-Nissan theory. Binary interaction coefficients are widely used in cubic EOS where they often are used as tuning parameters, especially if component j is an uncertain component (i.e. have uncertain parameter values).
Katti-Chaudhri (1964) mixing rule is
where is the partial molar volume of component i, and is the molar volume of the liquid phase and comes from the vapor-liquid equilibrium (VLE) calculation or the EOS for single phase liquid.
A modification of the Katti-Chaudhri mixing rule is
where is the excess activation energy of the viscous flow, and is the energy that is characteristic of intermolecular interactions between component i and component j, and therefore is responsible for the excess energy of activation for viscous flow. This mixing rule is theoretically justified by Eyring's representation of the viscosity of a pure fluid according to Glasstone et alios (1941). The quantity has been obtained from the time-correlation expression for shear viscosity by Zwanzig (1965).
Power series
Very often one simply selects a known correlation for the dilute gas viscosity , and subtracts this contribution from the total viscosity which is measured in the laboratory. This gives a residual viscosity term, often denoted , which represents the contribution of the dense fluid, .
The dense fluid viscosity is thus defined as the viscosity in excess of the dilute gas viscosity. This technique is often used in developing mathematical models for both purely empirical correlations and models with a theoretical support. The dilute gas viscosity contribution becomes important when the zero density limit (i.e. zero pressure limit) is approached. It is also very common to scale the dense fluid viscosity by the critical viscosity, or by an estimate of the critical viscosity, which is a characteristic point far into the dense fluid region. The simplest model of the dense fluid viscosity is a (truncated) power series of reduced mole density or pressure.
Jossi et al. (1962) presented such a model based on reduced mole density, but its most widespread form is the version proposed by
Lohrenz et al. (1964) which is displayed below.
The LBC-function is then expanded in a (truncated) power series with empirical coefficients as displayed below.
The final viscosity equation is thus
Local nomenclature list:
: mole density [mol/cm3]
: reduced mole density [1]
: molar mass [g/mol]
: critical pressure [atm]
: temperature [K]
: critical temperature [K]
: critical molar volume [cm3/mol]
: viscosity [cP]
Mixture
The formula for that was chosen by LBC, is displayed in the section called Dilute gas contribution.
Mixing rules
The subscript C7+ refers to the collection of hydrocarbon molecules in a reservoir fluid with oil and/or gas that have 7 or more carbon atoms in the molecule. The critical volume of C7+ fraction has unit ft3/lb mole, and it is calculated by
where is the specific gravity of the C7+ fraction.
The molar mass (or molecular mass) is normally not included in the EOS formula, but it usually enters the characterization of the EOS parameters.
EOS
From the equation of state the molar volume of the reservoir fluid (mixture) is calculated.
The molar volume is converted to mole density (also called mole concentration and denoted ), and then scaled to be reduced mole density .
Dilute gas contribution
The correlation for dilute gas viscosity of a mixture is taken from Herning and Zipperer
(1936) and is
The correlation for dilute gas viscosity of the individual components is taken from
Stiel and Thodos (1961) and is
where
Corresponding state principle
The principle of corresponding states (CS principle or CSP) was first formulated by van der Waals, and it says that two fluids (subscript a and z) of a group (e.g. fluids of non-polar molecules) have approximately the same reduced molar volume (or reduced compressibility factor) when compared at the same reduced temperature and reduced pressure. In mathematical terms this is
When the common CS principle above is applied to viscosity, it reads
Note that the CS principle was originally formulated for equilibrium states, but it is now applied on a transport property - viscosity, and this tells us that another CS formula may be needed for viscosity.
In order to increase the calculation speed for viscosity calculations based on CS theory, which is important in e.g. compositional reservoir simulations, while keeping the accuracy of the CS method, Pedersen et al.
(1984, 1987, 1989) proposed a CS method that uses a simple (or conventional) CS formula when calculating the reduced mass density that is used in the rotational coupling constants (displayed in the sections below), and a more complex CS formula, involving the rotational coupling constants, elsewhere.
Mixture
The simple corresponding state principle is extended by including a rotational coupling coefficient as suggested by Tham and Gubbins
(1970). The reference fluid is methane, and it is given the subscript z.
Mixing rules
The interaction terms for critical temperature and critical volume are
The parameter is usually uncertain or not available. One therefore wants to avoid this parameter. Replacing with the generic average parameter for all components, gives
The above expression for is now inserted into the equation for . This gives the following mixing rule
Mixing rule for the critical pressure of the mixture is established in a similar way.
The mixing rule for molecular weight is much simpler, but it is not entirely intuitive. It is an empirical combination of the more intuitive formulas with mass weighting and mole weighting .
The rotational coupling parameter for the mixture is
Reference fluid
The accuracy of the final viscosity of the CS method needs a very accurate density prediction of the reference fluid. The molar volume of the reference fluid methane is therefore calculated by a special EOS, and the Benedict-Webb-Rubin (1940) equation of state variant suggested by McCarty (1974), and abbreviated BWRM, is recommended by Pedersen et al. (1987) for this purpose. This means that the fluid mass density in a grid cell of the reservoir model may be calculated via e.g. a cubic EOS or by an input table with unknown establishment. In order to avoid iterative calculations, the reference (mass) density used in the rotational coupling parameters is therefore calculated using a simpler corresponding state principle which says that
The molar volume is used to calculate the mass concentration, which is called (mass) density, and then scaled to be reduced density which is equal to reciprocal of reduced molar volume because there is only on component (molecule type). In mathematical terms this is
The formula for the rotational coupling parameter of the mixture is shown further up, and the rotational coupling parameter for the reference fluid (methane) is
The methane mass density used in viscosity formulas is based on the extended corresponding state, shown at the beginning of this chapter on CS-methods. Using the BWRM EOS, the molar volume of the reference fluid is calculated as
Once again, the molar volume is used to calculate the mass concentration, or mass density, but the reference fluid is a single component fluid, and the reduced density is independent of the relative molar mass. In mathematical terms this is
The effect of a changing composition of e.g. the liquid phase is related to the scaling factors for viscosity, temperature and pressure, and that is the corresponding state principle.
The reference viscosity correlation of Pedersen et al. (1987) is
The formulas for , , are taken from Hanley et al.
(1975).
The dilute gas contribution is
The temperature dependent factor of the first density contribution is
The dense fluid term is
where exponential function is written both as and as . The molar volume of the reference fluid methane, which is used to calculate the mass density in the viscosity formulas above, is calculated at a reduced temperature that is proportional to the reduced temperature of the mixture. Due to the high critical temperatures of heavier hydrocarbon molecules, the reduced temperature of heavier reservoir oils (i.e. mixtures) can give a transferred reduced methane temperature that is in the neighborhood of the freezing temperature of methane. This is illustrated using two fairly heavy hydrocarbon molecules, in the table below. The selected temperatures are a typical oil or gas reservoir temperature, the reference temperature of the International Standard Metric Conditions for Natural Gas (and similar fluids) and the freezing temperature of methane ().
Pedersen et al. (1987) added a fourth term, that is correcting the reference viscosity formula at low reduced temperatures. The temperature functions and are weight factors. Their correction term is
Equation of state analogy
Phillips
(1912)
plotted temperature versus viscosity for different isobars for propane, and observed a similarity between these isobaric curves and the classic isothermal curves of the surface. Later, Little and Kennedy
(1968)
developed the first viscosity model based on analogy between and using van der Waals EOS. Van der Waals EOS was the first cubic EOS, but the cubic EOS has over the years been improved and now make up a widely used class of EOS. Therefore, Guo et al.
(1997)
developed two new analogy models for viscosity based on PR EOS (Peng and Robinson 1976) and PRPT EOS (Patel and Teja 1982)
respectively. The following year T.-M. Guo
(1998)
modified the PR based viscosity model slightly, and it is this version that will be presented below as a representative of EOS analogy models for viscosity.
PR EOS is displayed on the next line.
The viscosity equation of Guo (1998) is displayed on the next line.
To prepare for the mixing rules, the viscosity equation is re-written for a single fluid component i.
Details of how the composite elements of the equation are related to basic parameters and variables, is displayed below.
Mixture
Mixing rules
Friction force theory
Multi-parameter friction force theory
The multi-parameter version of the friction force theory (short FF theory and FF model), also called friction theory (short F-theory), was developed by Quiñones-Cisneros et al. (2000, 2001a, 2001b and Z 2001, 2004, 2006), and its basic elements, using some well known cubic EOSs, are displayed below.
It is a common modeling technique to accept a viscosity model for dilute gas (), and then establish a model for the dense fluid viscosity . The FF theory states that for a fluid under shear motion, the shear stress (i.e. the dragging force) acting between two moving layers can be separated into a term caused by dilute gas collisions, and a term caused by friction in the dense fluid.
The dilute gas viscosity (i.e. the limiting viscosity behavior as the pressure, normal stress, goes to zero) and the dense fluid viscosity (the residual viscosity) can be calculated by
where du/dy is the local velocity gradient orthogonal to the direction of flow. Thus
The basic idea of QZS (2000) is that internal surfaces in a Couette flow acts like (or is analogue to) mechanical slabs with friction forces acting on each surface as they slide past each other. According to the Amontons-Coulomb friction law in classical mechanics, the ratio between the kinetic friction force and the normal force is given by
where is known as the kinetic friction coefficient, A is the area of the internal flow surface, is the shear stress and is the normal stress (or pressure ) between neighboring layers in the Couette flow.
The FF theory of QZS says that when a fluid is brought to have shear motion, the attractive and repulsive intermolecular forces will contribute to amplify or diminish the mechanical properties of the fluid. The friction shear stress term
of the dense fluid can therefore be considered to consist of an attractive friction shear contribution and a repulsive friction shear contribution . Inserting this gives us
The well known cubic equation of states (SRK, PR and PRSV EOS), can be written in a general form as
The parameter pair (u,w)=(1,0) gives the SRK EOS, and (u,w)=(2,-1) gives both the PR EOS and the PRSV EOS because they differ only in the temperature and composition dependent parameter / function a. Input variables are, in our case, pressure (P), temperature (T) and for mixtures also fluid composition which can be single phase (or total) composition , vapor (gas) composition or liquid (in our example oil) composition . Output is the molar volume of the phase (V). Since the cubic EOS is not perfect, the molar volume is more uncertain than the pressure and temperature values.
The EOS consists of two parts that are related to van der Waals forces, or interactions, that originates in the static electric fields of the colliding parts /spots of the two (or more) colliding molecules. The repulsive part of the EOS is usually modeled as a hard core behavior of molecules, hence the symbol (Ph), and the attractive part (Pa) is based on the attractive interaction between molecules (conf. van der Waals force). The EOS can therefore be written as
Assume that the molar volume (V) is known from EOS calculations, and prior vapor-liquid equilibrium (VLE) calculations for mixtures. Then the two functions and can be utilized, and these functions are expected to be a more accurate and robust than the molar volume (V) itself. These functions are
The friction theory therefore assumes that the residual attractive stress and the residual repulsive stress are functions of the attractive pressure term and the repulsive pressure term , respectively.
The first attempt is, of course, to try a linear function in the pressure terms / functions.
All coefficients are in general functions of temperature and composition, and they are called friction functions. In order to achieve high accuracy over a wide pressure and temperature ranges, it turned out that a second order term was needed even for non-polar molecules types such as hydrocarbon fluids in oil and gas reservoirs, in order to achieve a high accuracy at very high pressures. A test with a presumably difficult 3-component mixture of non-polar molecule types needed a third order power to achieve high accuracy at the most extreme super-critical pressures.
This article will concentrate on the second order version, but the third order term will be included whenever possible in order to show the total set of formulas. As an introduction to mixture notation, the above equation is repeated for component i in a mixture.
The unit equations for the central variables in the multi-parameter FF-model is
Friction functions
Friction functions for fluid component i in the 5 parameter model for pure n-alkane molecules are presented below.
Friction functions for fluid component i in the 7- and 8-parameter models are presented below.
The empirical constants in the friction functions are called friction constants. Friction constants for some n-alkanes in the 5 parameter model using SRK and PRSV EOS (and thus PR EOS) is presented in tables below. Friction constants for some n-alkanes in the 7 parameter model using PRSV EOS are also presented in a table below. The constant for three fluid components are presented below in the last table of this table-series.
Mixture
In the single phase regions, the mole volume of the fluid mixture is determined by the input variables are pressure (P), temperature (T) and (total) fluid composition . In the two-phase gas-liquid region a vapor-liquid equilibrium (VLE) calculation splits the fluid into a vapor (gas) phase with composition and phase mixture molfraction ng and a liquid phase (in our example oil) with composition and phase mixture molfraction no. For liquid phase, vapor phase and single phase fluid the relation to VLE and EOS variables are
In a compositional reservoir simulator the pressure is calculated dynamically for each grid cell and each timestep. This gives dynamic pressures for vapor and liquid (oil) or single phase fluid. Assuming zero capillary pressure between hydrocarbon liquid (oil) and gas, the simulator software code will give a single dynamic pressure which applies to both the vapor mixture and the liquid (oil) mixture. In this case the reservoir simulator software code may use
or
The friction model for viscosity of a mixture is
The cubic power term is only needed when molecules with a fairly rigid 2-D structure are included in the mixture, or the user requires a very high accuracy at exemely high pressures. The standard model includes only linear and quadratic terms in the pressure functions.
Mixing rules
where the empirical weight fraction is
The recommended values for are
gave best performance for SRK EOS
gave best performance for PRSV EOS
These values are established from binary mixtures of n-alkanes using a 5-parameter viscosity model, and they seems to be used for 7- and 8-parameter models also. The motivation for this weight parameter , and thus the -parameter, is that in asymmetric mixtures like CH4 - C10H12, the lightest component tends to decrease the viscosity of the mixture more than linearly when plotted versus molfraction of the light component (or the heavy component).
The friction coefficients of some selected fluid components is presented in the tables below for the 5,7 and 8-parameter models. For convenience are critical viscosities also included in the tables.
.
One-parameter friction force theory
The one-parameter version of the friction force theory (FF1 theory and FF1 model) was developed by Quiñones-Cisneros et al.
(2000, 2001a, 2001b and
Z 2001, 2004),
and its basic elements, using some well known cubic EOSs, are displayed below.
The first step is to define the reduced dense fluid (or frictional) viscosity for a pure (i.e. single component) fluid by dividing by the critical viscosity. The same goes for the dilute gas viscosity.
The second step is to replace the attractive and repulsive pressure functions by reduced pressure functions. This will of course, affect the friction functions also. New friction functions are therefore introduced. They are called reduced friction functions, and they are of a more universal nature. The reduced frictional viscosity is
Returning to the unreduced frictional viscosity and rephrasinge the formula, gives
Critical viscosity is seldom measured and attempts to predict it by formulas are few. For a pure fluid, or component i in a fluid mixture, a formula from kinetic theory is often used to estimate critical viscosity.
where is a constant, and critical molar volume Vci is assumed to be proportional to the collision cross section. The critical molar volume Vci is significantly more uncertain than the parameters Pci and Tci. To get rid of Vci, the critical compressibility factor Zci is often replaced by a universal average value. This gives
where is a constant. Based on an average critical compressibility factor of Zc = 0.275 and measured critical viscosity values of 60 different molecule types, Uyehara and Watson (1944) determined an average value of Kp to be
Zéberg-Mikkelsen (2001) proposed an empirical correlation for Vci, with parameters for n-alkanes, which is
where . From the above equation and the definition of the compressibility factor it follows that
Zéberg-Mikkelsen (2001) also proposed an empirical correlation for ηci, with parameters for n-alkanes, which is
The unit equations for the two constitutive equations above by Zéberg-Mikkelsen (2001) are
The next step is to split the formulas into formulas for well defined components (designated by subscript d) with respect critical viscosity and formulas for uncertain components (designated by subscript u) where critical viscosity is estimated using and the universal constant which will be treated as a tuning parameter for the current mixture. The dense fluid viscosity (for fluid component i in a mixture) is then written as
The formulas from friction theory is then related to well defined and uncertain fluid components. The result is
However, in order to obtain the characteristic critical viscosity of the heavy pseudocomponents, the following modification of the Uyehara and Watson (1944) expression for the critical viscosity can be used. The frictional (or residual) viscosity is then written as
The unit equations are and and .
Reduced friction functions
The unit equation of is .
The 1-parameter model have been developed based on single component fluids in the series from methane to n-octadecane (C1H4 to C18H38). The empirical parameters in the reduced friction functions above are treated as universal constants, and they are listed in the following table. For convenience are critical viscosities included in the tables for models with 5- and 7-parameters that was presented further up.
.
Mixture
The mixture viscosity is given by
The mixture viscosity of well defined components is given by
The mixture viscosity function of uncertain components is given by
The mixture viscosity can be tuned to measured viscosity data by optimizing (regressing) the parameter .
where the mixture friction coefficients are obtained by eq(I.7.45) through eq(I.7.47) and and are the attractive and repulsive pressure term of the mixture.
Mixing rules
The mixing rules for the well defined components are
QZS recommends to drop the dilute gas term for the uncertain fluid components which are usually the heavier (hydrocarbon) components. The formula is kept here for consistency. The mixing rules for the uncertain components are
Dilute gas limit
Zéberg-Mikkelsen (2001) proposed an empirical model for dilute gas viscosity of fairly spherical molecules as follows
or
The unit equations for viscosity and temperature are
The second term is a correction term for high temperatures. Note that most parameters are negative.
.
Light gases
Zéberg-Mikkelsen (2001) proposed a FF-model for light gas viscosity as follows
The friction functions for light gases are simple
The FF-model for light gas is valid for low, normal, critical and super critical conditions for these gases. Although the FF-model for viscosity of dilute gas is recommended, any accurate viscosity model for dilute gas can also be used with good results.
The unit equations for viscosity and temperature are
.
Transition state analogy
This article started with viscosity for mixtures by displaying equations for dilute gas based on elementary kinetic theory, hard core (kinetic) theory and proceeded to selected theories (and models) that aimed at modeling viscosity for dense gases, dense fluids and supercritical fluids. Many or most of these theories where based on a philosophy of how gases behaves with molecules flying around, colliding with other molecules and exchanging (linear) momentum and thus creating viscosity. When the fluid became liquid, the models started to deviate from measurements because a small error in the calculated molar volume from the EOS is related to a large change in pressure and vica versa, and thus also in viscosity. The article has now come to the other end where theories (or models) are based on a philosophy of how a liquid behaves and give rise to viscosity. Since molecules in a liquid are much closer to each other, one may wonder how often a molecule in one sliding fluid surface finds a free volume in the neighboring sliding surface that is big enough for the molecule to jump into it. This may be rephrased as: when do a molecule have enough energy in its fluctuating movements to squeeze into a small open volume in the neighboring sliding surface, similar to a molecule that collides with another molecule and locks into it in a chemical reaction, and thus creates a new compound, as modeled in the transition state theory (TS theory and TS model).
Free volume theory
The free volume theory (short FV theory and FV model) originates from
Doolittle (1951)
who proposed that viscosity is related to the free volume fraction in a way that is analogous to the Arrhenius equation. The viscosity model of Doolittle (1951) is
where is the molar volume and is the molar hard core volume.
There where, however, little activity on the FV theory until
Allal et al. (1996, 2001a)
proposed a relation between the free volume fraction and parameters (and/or variables) at the molecular level of the fluid (also called the microstructure of the fluid). The 1996-model became the start of a period with high research activity where different models were put forward. The surviving model was presented by Allal et al. (2001b), and this model will be displayed below.
The viscosity model is composed of a dilute gas contribution (or ) and a dense-fluid contribution (or dense-state contribution or ).
Allal et al. (2001b) showed that the dense-fluid contribution to viscosity can be related to the friction coefficient of the sliding fluid surface, and Dulliens (1963) has shown that the self-diffusion coefficient is related to the friction coefficient of an internal fluid surface. These two relations are shown here:
By eliminating the friction coefficient , Boned et al. (2004)
expressed the characteristic length as
The right hand side corresponds to the so-called Dullien invariant which was derived by Dullien (1963, 1972).
A result from this is that the characteristic length is interpreted as the average momentum transfer distance to a molecule that will enter a free volume site and collide with a neighboring molecule.
The friction coefficient is modeled by Allal et alios (2001b) as
The free volume fraction is now related to the energy E by
where is the total energy a molecule must use in order to diffuse into a vacant volume, and is connected to the work (or energy) necessary to form or expand a vacant volume available for diffusion of a molecule. The energy is the barrier energy that the molecule must overcome in order to diffuse, and it is modeled to be proportional to mass density in order to improve match of measured viscosity data. Note that the sensitive term in the denominator of Doolittle's (1951) model has disappeared, making the viscosity model of Allal et alios (2001b) more robust to numerical calculations of liquid molar volume by an imperfect EOS. The pre-exponential factor A is now a function and becomes
The viscosity model proposed by Allal et al.(2001b) is thus
A digression is that the self-diffusion coefficient of Boned et al. (2004) becomes
Local nomenclature list:
parameter that characterizes the free volume overlap or empirical tuning parameter [1]
molar hard core volume [m3/mol]
total energy which the molecule must use in order to diffuse [J/mole]
barrier energy which the molecule must overcome in order to diffuse [J/mole]
average momentum transfer distance for a molecular that transfer linear momentum (conf. hard core radius) and/or angular momentum (conf. radius of gyration) [Å]
dissipation length to the energy E [Å]
composite parameter that is characteristic for viscosity [Å]
molar mass, conf. molecular weight [kg/mol]
Avogadros constant
pressure [MPa]
gas constant R = 8.31451 [K·J/mol]
molar volume [m3/mol]
characteristic parameter or empirical tuning parameter [1]
viscosity [Pas]
mass density [kg/m3]
friction coefficient of a molecule related to the mobility of the molecule [1]
friction coefficient for zero mass density i.e. for a dilute system / low pressure limit [1]
Mixture
The mixture viscosity is
The dilute gas viscosity is taken from Chung et al.(1988) which is displayed in the section on SS theory. The dense fluid contribution to viscosity in FV theory is
where are three characteristic parameters of the fluid w.r.t. viscosity calculations. For fluid mixtures are these three parameters calculated using mixing rules. If the self-diffusion coefficient is included in the governing equations, probably via the diffusion equation, use of four characteristic parameters (i.e. use of Lp and Ld instead of Lc) will give a consistent flow model, but flow studies that involves the diffusion equation belongs a small class of special studies.
The unit for the viscosity is [Pas], when all other units are kept in SI units.
Mixing rules
At the end of the intensive research period
Allal et al. (2001c)
and Canet (2001)
proposed two different set of mixing rules, and according to
Almasi (2015)
there has been no agreement in the literature about which are the best mixing rules. Almasi (2015) therefore recommended the classic linear mole weighted mixing rules which are displayed below for a mixture of N fluid components.
The three characteristic viscosity parameters are usually established by optimizing the viscosity formula against measured viscosity data for pure fluids (i.e. single component fluids).
Trend functions
The three characteristic viscosity parameters are usually established by optimizing the viscosity formula against measured viscosity data for pure fluids (i.e. single component fluids). Data for these parameters can then be stored in databases together with data for other chemical and physical material properties and information. This happens more often if use of the equation becomes widespread. Hydrocarbon molecules is a huge group of molecules that has several subgroups which itself contains molecules of the same basic structure, but with different lengths. The alkanes is the simplest of these groups. A material property of molecules in such a group normally shows up as a function when plotted against another material property. A mathematical function is then selected based physical/chemical knowledge, experience and intuition, and the empirical parameters (i.e. constants) in the function are determined by curve fitting. Such a function is called a trend or trend function, and the group of molecule types is called a homologous series. Llovell et al. (2013a, 2013b)
proposed trend functions for the three FV parameters for alkanes.
Oliveira et al. (2014)
proposed trend functions for the FV parameters for fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE), both including compounds with up to three unsaturated bonds, which are displayed below.
The molar mass M [g/mol] (or molecular mass / weight) associated with the parameters used in curve fitting process (where , , and are empirical parameters) corresponds to carbon numbers in the range 8-24 and 8-20 for FAME and FAEE respectively.
Significant structure theory
Viscosity models based on significant structure theory, a designation originating from
Eyring,
(short SS theory and SS model) has in the first two decades of the 2000s evolved in a development relay. It starting with
Macías-Salinas et al.(2003),
continued with a significant contribution from
Cruz-Reyes et al.(2005),
followed by a third stage of development by
Macías-Salinas et al.(2013),
whose model is displayed here. The SS theories have three basic assumptions:
A liquid behaves similar to a solid in many aspects, e.g. a sensitive relation between molar volume (or mass density) and pressure; position and distance between molecules is like a quasi-lattice with "fluidized vacancies" of molecular size distributed randomly throughout the quazi-lattice. The vacancies are assumed to have molecular size and move freely throughout the quasi-lattise structure.
The fluid viscosity is calculated from two components which is a gas-like and a solid-like contribution, and both contributions contain all molecule types occurring in the fluid phase. A molecule that jumps from one sliding surface to a vacant site in the neighboring surface, is said to display gas-like behavior. A molecule that remains on its site in the sliding surface for some time, is said to display solid-like behavior.
Collisions between molecules from neighboring layers are equivalent to molecules jumping to vacant sites, and these events within viscosity modeling are analogous to chemical reactions between colliding molecules within TS theory.
The fraction of gas-like molecules and solid-like molecules are
where is the molar volume of the phase in question, is the molar volume of solid-like molecules and is the molar hard core volume. The viscosity of the fluid is a mixture of these two classes of molecules
Gas-like contribution
The gas-like viscosity contribution is taken from the viscosity model of
Chung et al.(1984, 1988),
which is based on the Chapman–Enskog(1964)
kinetic theory of viscosity for dilute gases and the empirical expression of
Neufeld et al.(1972)
for the reduced collision integral, but expanded empirical to handle polyatomic, polar and hydrogen
bonding fluids over a wide temperature range. The viscosity model of Chung et al.(1988) is
where
Local nomenclature list:
: factor for molecular shape and polarities of dilute gases [1]
: molar mass, conf. molecular weight [g/mol]
: temperature [K]
: critical temperature [K]
: molar critical volume [cm3/mol]
: gas-like viscosity contribution [μP]
: correction factor for hydrogen bonding effects [1]
: reduced dipole moment [1]
: reduced collision integral [1]
: acentric factor [1]
Solid-like contribution
In the 2000s, the development of the solid-like viscosity contribution started with
Macías-Salinas et al.(2003) who used the Eyring equation in TS theory as an analogue to the solid-like viscosity contribution, and as a generalization of the first exponential liquid viscosity model proposed by Reynolds(1886).
The Eyring equation models irreversible chemical reactions at constant pressure, and the equation therefore uses Gibbs activation energy, , to model the transition state energy that the system uses to move matter (i.e. separate molecules) from the initial state to the final state (i.e. the new compound). In the Couette flow, the system moves matter from one sliding surface to another, due to fluctuating internal energy, and probably also due to pressure and the pressure gradient. Besides, the pressure effect on viscosity is somewhat different for systems in a medium pressure range than it is for systems in a very high pressure range.
Cruz-Reyes et al.(2005) uses Helmholtz energy (F = U-TS = G-PV) as potential in the exponential function. This gives
Cruz-Reyes et al.(2005) states that the Gibbs activation energy is negative proportional to the internal energy of vaporization (and thus calculated at a point on the freezing curve), but Macías-Salinas et al.(2013) changes that to be the residual internal energy, , at the general pressure and temperature of the system. One could alternatively use the grand potential ( = U-TS-G = -PV, sometimes called Landau energy or potential) in the exponential function and argue that the Couette flow is not a homogeneous system, such that a term with the residual internal energy must be added. Both arguments gives the proposed solid-like contribution which is
The pre-exponential factor is taken as
The jumping frequency of a molecule that jumps from its initial position to a vacant site, , is made dependent on the number of vacancies, , and pressure in order to extend the applicability of to much wider ranges of temperature and pressure than a constant jumping frequency would do. The final jumping frequency model is
A recurrent problem for viscosity models is the calculation of liquid molar volume for a given pressure using an EOS that is not perfect. This calls for introduction of some empirical parameters. Use of adjustable proportionality factors for both the residual internal energy and the Z-factor is a natural choice. The sensitivity of P versus V-b values for liquids makes it natural to introduce an empirical exponent (power) to the dimensionless Z-factor. The empirical power turns out to be very effective in the high pressure (high Z-factor) region. The solid-like viscosity contribution proposed by Macías-Salinas et al.(2013) is then
Local nomenclature list:
: molar hard core volume of the fluid phase [cm3/mol]
: pressure [bar]
: temperature [K]
: molar volume of the fluid phase [cm3/mol]
: volume fraction of the j-like contribution j=g,s [1]
: compressibility factor (Z-factor) [1]
: proportionality factor [1]
: adjustable parameters i=0,1 [1]
: viscosity of the fluid phase [μPa·s]
: solid-like viscosity contribution [μPa·s]
: adjustable parameters i=0,1 [s−1] and [bar−1s−1]
: activation energy of the fluid [J/mol]
: residual internal energy of the fluid [J/mol]
Mixture
In order to clarify the mathematical statements above, the solid-like contribution for a fluid mixture is displayed in more details below.
Mixing rules
The variables and all EOS parameters for a fluid mixture are taken from the EOS (conf. W) and the mixing rules used by the EOS (conf. Q). More details on this is displayed below.
A fluid of n mole in the single phase region where the total fluid composition is [molefractions]:
Gas phase of ng mole in two-phase region where the gas composition is [molefractions]:
Liquid phase of nl mole in two-phase region where the liquid composition is [molefractions]:
where
Since nearly all input to this viscosity model is provided by the EOS and the equilibrium calculations, this SS model (or TS model) for viscosity should be very simple to use for fluid mixtures. The viscosity model also have some empirical parameters that can be used as tuning parameters to compensate for imperfect EOS models and secure high accuracy also for fluid mixtures.
See also
Collision theory
Compressibility factor
Concentration
Conversion of units
Curve fitting
Dortmund Data Bank
Ideal gas
Ideal gas law
Kinetic theory of gases
List of thermodynamic properties
Molar volume
PSRK
Real gas
Real gas law
Statistical mechanics
Statistical physics
Table of thermodynamic equations
Transport phenomena
Trend estimation
VTPR
References
Viscosity | Viscosity models for mixtures | [
"Physics"
] | 12,556 | [
"Physical phenomena",
"Physical quantities",
"Wikipedia categories named after physical quantities",
"Viscosity",
"Physical properties"
] |
56,542,129 | https://en.wikipedia.org/wiki/Hydraulis%20of%20Dion | The Hydraulis of Dion () is a unique exhibit of the Archaeological Museum of Dion. It is the earliest archeological example of a pipe organ to date.
Excavation history
At the beginning of the 1980s, the area was drained east of the main road of ancient Dion. The neighboring river had permanently flooded parts of the archaeological site. In this area, east of the main road, excavations were carried out in the summer of 1992 under the direction of Dimitrios Pandermalis. Opposite the villa of Dionysus, the foundations of a building were uncovered. On the morning of August 19, 1992, archaeologists found pieces of small copper tubes. Furthermore, one found a larger, rectangular, copper plate. The individual finds were partially connected by the compacted soil. After recognizing the meaning of the find, the earth was widely removed and sent for further processing to the workshops. After cleaning the items, it was recognized that it was a musical instrument, a hydraulis. The find was dated to the 1st century BC.
The instrument
The Pipe organ is considered the oldest keyboard instrument in the world. It was built in the 3rd century BC, invented by the engineer Ctesibius in Alexandria.
The height of the instrument is 120 cm, width 70 cm. The organ pipes are arranged in two stops and consist of 24 pipes with a diameter of 18 mm and 16 narrow pipes with about 10 mm diameter. They were decorated with silver rings. The body of the organ was decorated with silver stripes and multicolored, rectangular glass ornaments. Valves were opened by keyboard and the air flowing through the organ pipe generated the sound. The instrument is structurally classified between the water organ described by Hero of Alexandria and Vitruvius.
Spreading as a musical instrument
After its invention in the Egyptian Alexandria, the organ arrived in Greece in the Hellenistic period. After its conquest by the Romans it was spread in the Roman Empire. There it was used for musical accompaniment in the competitions in the arenas and played by the wealthy as a domestic musical instrument. At the Byzantine court the hydraulis was a prestigious object. In 757, Constantine V sent an organ as a gift to the French king Pippin the Short. So it came to Central Europe and was discovered by the Catholic Church and eventually developed into a church organ.
Replica of the hydraulis of Dion
With the support of the Greek Ministry of Culture and Sport and the help of Professor Pandermalis, a reconstruction of a water organ was started at the European Cultural Center of Delphi in 1995. They kept to ancient records and to the original excavated in Dion. The instrument was completed in 1999.
Literature
Dimitrios Pandermalis: Η Ύδραυλις του Δίου. In: Ministry for culture, Ministry for Macedonia and Thrace, Aristotle-University Thessaloniki: Το Αρχαιολογικό Έργο στη Μακεδονία και Θράκη. Volume 6, 1992, Thessaloniki 1995, pages. 217–222. (Greek language)
Dimitrios Pandermalis: Dion. The archaeological site and the museum. Athens 1997.
Hellenic Republic, Ministry of culture and sports, Onassis Foundation USA: Gods and Mortals at Olympus. S. 26, Edited by Dimitrios Pandermalis, .
Free Travel Guide about the Olympus region Title: Mount Olympus - Ancient Sites, Museums, Monasteries and Churches
References
External links
Ministry of Culture and Sports Archaeological Museum of Dion
The ancient Hydraulis
Hydraulis 24/40 - Órgano de Dión - Prof. Manuel Lafarga
Professor Pantermalis talks about the Hydraulis of Dion (Dion, 10 August 2018, in Greek language)
Ancient Greek musical instruments
Ancient Roman musical instruments
Greek inventions
Hellenistic engineering
Organs (music)
Pipe organ
Ancient inventions
Water
Archaeological discoveries in Macedonia (Greece)
1992 archaeological discoveries | Hydraulis of Dion | [
"Environmental_science"
] | 792 | [
"Water",
"Hydrology"
] |
56,543,109 | https://en.wikipedia.org/wiki/Investment%20Data%20Standards%20Organization | The Investment Data Standards Organization (IDSO) is a U.S.-based organization that publishes Alternative Data standards. IDSO was established to support the growth of the Alternative Data industry through the creation, development, and maintenance of industry-wide standards and best practices. IDSO is a non-profit 501(c)(6) organization made up of companies in the Alternative Data industry such as data originators, intermediaries, and institutional investment funds.
Overview
The Investment Data Standards Organization is an independent, non-governmental organization that publishes Alternative Data standards and best practices for personally identifiable information (PII), web crawling, and other security and compliance-related topics. Consisting of companies in the Alternative Data industry such as data originators, research providers, aggregators, and investment funds, the Investment Data Standards Organization (IDSO) represents the interests of Alternative Data industry participants and supports the acceptance and adoption of Alternative Data by institutional investors. The use of standards enables robust and reliable Alternative Data products and services that meet U.S. privacy and security requirements.
Membership
IDSO serves managers and compliance teams in the Alternative Data industry who are interested in regulatory guidance. Companies that participate in the Alternative Data ecosystem include:
Raw data originators, who collect or generate data,
Research providers, who produce original research and derived signals,
Aggregators, who enrich and aggregate data, and
Investment funds, who use data to add value to their investment process.
IDSO publications are developed by working groups composed of representatives from these Alternative Data organizations. IDSO members work together in teams to create and edit standards and best practices.
Membership Functions
Investment Data Standards Organization (IDSO) members access IDSO publications, interact with industry participants, and drive change to help shape the future of the Alternative Data industry.
Publications
IDSO's main products are standards, checklists, technical reports, technical specifications, and guides. The standards currently available are related to personally identifiable information (PII), web crawling, and dataset compliance for sensitive information (SI):
Personally identifiable information (PII): The PII publications develop processes and risk management strategies for identifying, maintaining, and securing personally identifiable information (PII) in data sets used for investment management.
Web crawling: The web crawling publications provide processes and procedures for data harvested or scraped from the web.
Dataset compliance for sensitive information (SI): The dataset compliance publications assign a dataset compliance-level to datasets that contain sensitive information (SI).
References
Data management
Non-profit organizations based in New York City
Organizations established in 2017
Standards organizations in the United States | Investment Data Standards Organization | [
"Technology"
] | 528 | [
"Data management",
"Data"
] |
56,543,112 | https://en.wikipedia.org/wiki/Gladys%20West | Gladys Mae West (née Brown; born October 27, 1930) is an American mathematician. She is known for her contributions to mathematical modeling of the shape of the Earth, and her work on the development of satellite geodesy models, that were later incorporated into the Global Positioning System (GPS). West was inducted into the United States Air Force Hall of Fame in 2018. West was awarded the Webby Lifetime Achievement Award for the development of satellite geodesy models.
Early life and education
Gladys Mae Brown was born in Sutherland, Virginia, in Dinwiddie County, a rural county south of Richmond. Her family was an African-American farming family in a community of sharecroppers. She spent much of her childhood working on her family's small farm. As well as working on the farm, her mother worked in a tobacco factory and her father worked for the railroad. West saw education as her way to a different life.
At West's high school, the top two students from each graduating class received full scholarships to Virginia State College (now Virginia State University), a historically black public university. West graduated as valedictorian in 1948, and received the scholarship. At VSU, West chose to study mathematics, a subject that was mostly studied at her college by men. She also joined the Alpha Kappa Alpha sorority. West graduated in 1952 with a Bachelor of Science degree in mathematics, and then taught math and science for two years in Waverly, Virginia. West returned to VSU to complete a Master of Mathematics degree, graduating in 1955. Afterward, she began another teaching position in Martinsville, Virginia.
Career
In 1956, West was hired to work at the Naval Proving Ground in Dahlgren, Virginia (now the Naval Surface Warfare Center). Here, she was the second black woman ever hired and one of only four black employees. West was a computer programmer in the Dahlgren division, and a project manager for processing systems for satellite data analysis. Concurrently, West earned a Master's degree in Public Administration from the University of Oklahoma.
In the early 1960s, West participated in an award-winning study that proved the regularity of Pluto’s motion relative to Neptune. Subsequently, West began to analyze satellite altimeter data from NASA's Geodetic Earth Orbiting program, to create models of the Earth's shape. She became project manager for the Seasat radar altimetry project, the first satellite that could remotely sense oceans. West's work cut her team's processing time in half, and she was recommended for a commendation.
From the mid-1970s through the 1980s, West programmed an IBM 7030 Stretch computer to deliver increasingly precise calculations for the shape of the Earth; an ellipsoid with additional undulations known as the geoid. To generate an accurate geopotential model West needed to use complex algorithms to account for variations in the gravitational, tidal, and other forces that distort Earth's shape.
In 1986, West published Data Processing System Specifications for the Geosat Satellite Radar Altimeter, a 51-page technical report from the Naval Surface Weapons Center (NSWC). This explained how to improve the accuracy of geoid heights and vertical deflection, important components of satellite geodesy. This was achieved by processing data from the radio altimeter on the Geosat satellite, which went into orbit on March 12, 1984.
West worked at Dahlgren for 42 years, and retired in 1998. In 2000, she completed a PhD in Public Administration at Virginia Tech by distance-learning.
Legacy
West's vital contributions to GPS technology were recognized when a member of her sorority Alpha Kappa Alpha read a short biography West had submitted for an alumni function.
West was inducted into the United States Air Force Hall of Fame in 2018, one of the highest honors bestowed by Air Force Space Command (AFSPC). The AFSPC press release hailed her as one of "the 'Hidden Figures' part of the team who did computing for the US military in the era before electronic systems", a reference to the 2016 book by Margot Lee Shetterly, which was adapted into the film Hidden Figures. Capt. Godfrey Weekes, commanding officer at the Naval Surface Warfare Center Dahlgren Division, described the role played by West in the development of Global Positioning System: "She rose through the ranks, worked on the satellite geodesy, and contributed to the accuracy of GPS and the measurement of satellite data. As Gladys West started her career ... in 1956, she likely had no idea that her work would impact the world for decades to come." West agreed, saying "When you’re working every day, you’re not thinking, 'What impact is this going to have on the world?' You're thinking, 'I've got to get this right.'"
As an alumna of Virginia State University, West won the award for "Female Alumna of the Year" at the Historically Black Colleges and Universities Awards in 2018.
West was selected by the BBC as part of their 100 Women of 2018. In 2021, she was awarded the Prince Philip Medal by the UK's Royal Academy of Engineering, their highest individual honor.
In 2024, Virginia's Fredericksburg City School Board voted to name its third elementary school in her honor: Gladys West Elementary School.
Personal life
West met her husband Ira at the Naval Surface Warfare Center Dahlgren Division, where he also worked as a mathematician. They were two of only four black employees at the time. They were married in 1957. They have three children (Carolyn, David and Michael), and seven grandchildren. The West family went to Chapel on the Proving Ground every Sunday. , West lives in King George County, Virginia. Her husband died on October 20, 2024.
Before being hired, West initially turned down the job due to its location and the requirement to interview. West did not have a car and could not find Dahlgren on a map, and she believed that they would reject her after the interview because of her race, so she decided to wait to hear back from other applications. However, Dahlgren contacted her again, offering her the job without the need to interview. The job offered twice the salary of her teaching position. Being hired solely on her qualifications, with a salary that would eventually help her support her family, was a rare find for a black woman at that time.
In 1954, the Supreme Court had made a landmark decision on Brown vs. Board of Education, ruling that American state laws that established racial segregation in public schools were unconstitutional. However, Virginia was still segregated since the Supreme Court had not specified which states were required to reestablish in accordance to the new ruling. Groups such as the Ku Klux Klan were still at large, and the prospect of moving to a rural neighborhood in a southern state was daunting for an unmarried black woman.
The Civil Rights movement was fully underway during her time at the base. Though she supported the movement, she could not participate in protests because she was a government employee. In Boomtown, where married people lived on base, she was part of a club of black women who discussed civil rights topics.
During her career, West encountered many hardships because of racism against African Americans. A prime example was the lack of recognition she received while working, while her white coworkers received praise and added privileges. Her biography makes clear her disappointment at not being granted projects that included travel and exposure.
West continues to prefer using paper maps over GNSS-based navigation systems, saying, "I'm a doer, hands-on kind of person. If I can see the road and see where it turns and see where it went, I am more sure."
Publications
See also
Irene Fischer
List of African-American women in STEM fields
References
Further reading
1930 births
20th-century African-American people
20th-century African-American women
20th-century American mathematicians
20th-century American scientists
20th-century American women scientists
20th-century American women mathematicians
21st-century African-American people
21st-century African-American women
African-American computer scientists
African-American mathematicians
African-American women mathematicians
American computer scientists
American geodesists
American women computer scientists
American computer programmers
Living people
Mathematicians from Virginia
People associated with the Global Positioning System
People from Dinwiddie County, Virginia
People from King George County, Virginia
Scientists from Virginia
University of Oklahoma alumni
Virginia State University alumni
Virginia Tech alumni | Gladys West | [
"Technology"
] | 1,712 | [
"Global Positioning System",
"People associated with the Global Positioning System"
] |
56,543,559 | https://en.wikipedia.org/wiki/Pooled%20analysis | A pooled analysis is a statistical technique for combining the results of multiple epidemiological studies. It is one of three types of literature reviews frequently used in epidemiology, along with meta-analysis and traditional narrative reviews. Pooled analyses may be either retrospective or prospective. It is often used when the results of individual studies do not allow for a firm conclusion to be drawn. Unlike meta-analyses, pooled analyses can only be conducted if the included studies used the same study design and statistical models, and if their respective populations were homogeneous. If individual-level data from the included studies is available, the result of a pooled analysis can be considered more reliable.
References
Epidemiology
Research methods
Clinical research
Statistical analysis | Pooled analysis | [
"Environmental_science"
] | 149 | [
"Epidemiology",
"Environmental social science"
] |
56,543,622 | https://en.wikipedia.org/wiki/Katherine%20Heinrich | Katherine A. Heinrich (born 21 February 1954) is a mathematician and mathematics teacher who was the first female president of the Canadian Mathematical Society. Her research interests include graph theory and the theory of combinatorial designs. Originally from Australia, she moved to Canada where she worked as a professor at Simon Fraser University and as an academic administrator at the University of Regina.
Education and career
Heinrich was born in Murwillumbah, New South Wales. As an undergraduate at the University of Newcastle in Australia, she graduated as a University Medalist in 1976. She continued at Newcastle as a graduate student and completed her doctorate there in 1979. Her dissertation, "Some problems on combinatorial arrays", was supervised by Walter D. Wallis.
Heinrich joined the mathematics faculty at Simon Fraser University in 1981, and married another graph theorist there, Brian Alspach. She became a full professor in 1987 and chaired the department from 1991 to 1996. While working at Simon Fraser, she co-ordinated several outreach activities including a conference for pre-teen girls called "Women Do Math" and later "Discover the Possibilities", a shopping-center exhibit called "Math in the Malls", and a series of national conferences on mathematics education.
From 1996 to 1998, she was the president of the Canadian Mathematical Society, its first female president. In 1999, she moved to the University of Regina as academic vice president and, in 2003, she was confirmed for a second five-year term as vice president. At Regina, she helped to establish an institute for French-language education and built stronger connections between Regina and the First Nations University of Canada.
She retired in 2007 and returned to Newcastle, New South Wales, where she is active in textile arts.
Research
MathSciNet lists 73 publications for Heinrich, dated from 1976 to 2012. Several of her research publications concern orthogonal Latin squares, analogous concepts in graph theory and applications of these concepts in parallel computing. She has also published works on finding spanning subgraphs with constraints on the degree of each vertex and on Alspach's conjecture on disjoint cycle covers of complete graphs, among other topics.
Selected publications
Recognition
The University of Newcastle gave Heinrich a Gold Medal for Professional Excellence in 1995. In 2005, she won the Adrien Pouliot Award of the Canadian Mathematical Society for her work in mathematics education.
References
1954 births
Living people
Australian mathematicians
Australian women mathematicians
Canadian mathematicians
Graph theorists
Mathematics educators
University of Newcastle (Australia) alumni
Academic staff of Simon Fraser University
Academic staff of the University of Regina
Presidents of the Canadian Mathematical Society | Katherine Heinrich | [
"Mathematics"
] | 516 | [
"Mathematical relations",
"Graph theory",
"Graph theorists"
] |
56,545,656 | https://en.wikipedia.org/wiki/High%20explosive%20nuclear%20effects%20testing | High explosive nuclear effects testing comprises large scale field tests using conventional high explosives as alternatives to atmospheric nuclear testing.
Background
When the Limited Test Ban Treaty came into effect in 1963, nuclear testing in the atmosphere was prohibited. However, alternatives to atmospheric nuclear testing were required to continue the study of nuclear weapons effects. These would allow obtaining data related to air-blast, ground-shock, structure-response data, bio-medical effects, and other various phenomena. Large scale field tests using conventional high explosives were devised to this end.
Events
The following is a list of such events with yields of more than 1000 pounds.
See also
Largest artificial non-nuclear explosions
List of nuclear weapons tests
References
Nuclear weapons testing | High explosive nuclear effects testing | [
"Technology"
] | 140 | [
"Environmental impact of nuclear power",
"Nuclear weapons testing"
] |
56,546,873 | https://en.wikipedia.org/wiki/Zuranolone | Zuranolone, sold under the brand name Zurzuvae, is a medication used for the treatment of postpartum depression. It is taken by mouth.
The most common side effects include drowsiness, dizziness, diarrhea, fatigue, nasopharyngitis, and urinary tract infection. An orally active inhibitory pregnane neurosteroid, zuranolone acts as a positive allosteric modulator of the GABAA receptor.
Zuranolone was approved for medical use in the United States for the treatment of postpartum depression in August 2023. It was developed by Sage Therapeutics and Biogen.
Medical uses
Zuranolone is indicated for the treatment of postpartum depression.
Adverse effects
The most common side effects include drowsiness, dizziness, diarrhea, fatigue, and urinary tract infection.
The US FDA label contains a boxed warning noting that zuranolone can impact a person's ability to drive and perform other potentially hazardous activities. The use of zuranolone may cause suicidal thoughts and behavior. Zuranolone may also cause fetal harm.
History
Zuranolone was developed as an improvement on the intravenously administered neurosteroid brexanolone, with high oral bioavailability and a biological half-life suitable for once-daily administration. Its half-life is around 16 to 23hours, compared to approximately 9hours for brexanolone.
The efficacy of zuranolone for the treatment of postpartum depression in adults was demonstrated in two randomized, double-blind, placebo-controlled, multicenter studies. The trial participants were women with postpartum depression who met the Diagnostic and Statistical Manual of Mental Disorders criteria for a major depressive episode and whose symptoms began in the third trimester or within four weeks of delivery. In study 1, participants received 50 mg of zuranolone or placebo once daily in the evening for 14 days. In study 2, participants received another zuranolone product that was approximately equal to 40 mg of zuranolone or placebo, also for 14 days. Participants in both studies were monitored for at least four weeks after the 14-day treatment. The primary endpoint of both studies was the change in depressive symptoms using the total score from the 17-item Hamilton depression rating scale (HAMD-17), measured at day 15. Participants in the zuranolone groups showed significantly more improvement in their symptoms compared to those in the placebo groups. The treatment effect was maintained at day 42—four weeks after the last dose of zuranolone.
Society and culture
Zuranolone is the international nonproprietary name.
Legal status
Zuranolone was approved by the US Food and Drug Administration (FDA) for the treatment of postpartum depression in August 2023. The FDA granted the application for zuranolone priority review and fast track designations. Approval of Zurzuvae was granted to Sage Therapeutics, Inc.
Zuranolone has also been under development for the treatment of major depressive disorder, but the application for this use was given a Complete Response Letter (CRL) by the FDA due to insufficient evidence of effectiveness.
In the United States, zuranolone is a Schedule IV controlled substance.
Research
In a randomized, placebo-controlled phase III trial to assess its efficacy and safety for the treatment of major depressive disorder, subjects in the zuranolone group (50 mg oral zuranolone once daily for 14 days) experienced statistically significant and sustained improvements in depressive symptoms (as measured by HAM-D score) throughout the treatment and follow-up periods of the study.
Other investigational applications include insomnia, bipolar depression, essential tremor, and Parkinson's disease.
References
External links
5β-Pregnanes
Alcohols
Anticonvulsants
Antidepressants
GABAA receptor positive allosteric modulators
Ketones
Neurosteroids
Nitriles
Pyrazoles | Zuranolone | [
"Chemistry"
] | 815 | [
"Ketones",
"Nitriles",
"Functional groups"
] |
56,547,387 | https://en.wikipedia.org/wiki/Antigen%20transfer%20in%20the%20thymus | Antigen transfer in the thymus is the transmission of self-antigens between thymic antigen-presenting cells which contributes to the establishment of T cell central tolerance.
Thymus represents an origin of T cell development and its responsibility is to select functional but also safe T cells which will not attack self tissues. Self-harmful T cells, further referred to as autoreactive T cells, originate in the thymus because of the stochastic process called V(D)J recombination which conducts the generation of T cell receptors (TCRs) and enables their limitless variability. Two processes of central tolerance take place in thymic medulla, namely clonal deletion (recessive tolerance) and T Regulatory cells selection (dominant tolerance) which force autoreactive T cells to apoptosis or skew them into suppressor T regulatory cells (TRegs), respectively, in order to protect body against manifestations of autoimmunity.
These processes are mediated especially by unique subset of stromal cells called Medullary thymic epithelial cells (mTECs) via presentation of Tissue restricted antigens (TRAs) that represent self tissues from almost all parts of the body.
mTECs
mTECs are not only capable to present TRAs as efficient APCs. They are also potent in production of these TRAs via unique process called promiscuous gene expression (PGE) and might serve as their reservoir.
Drawbacks of antigen presentation
mTECs as APCs reveal some drawbacks on population level. Their numbers in thymic medulla reach only 100,000 per 2-week-old thymus. Furthermore, average lifespan of mTECs does not exceed 2–3 days, probably due to only known PGE activator Autoimmune regulator (Aire), which requires for its proper function generation of DNA double strand breaks. And last but not least, each TRA is expressed only by 1-3% of mTEC population. These facts decrease the chance of efficient recessive or dominant tolerance.
Relevance of antigen transfer
Unidirectional spreading of mTEC-derived TRAs onto additional APCs via antigen transfer increases the probability of encounter between potential autoreactive T cell and its corresponding TRA and therefore enhances processes of central tolerance. Furthermore, antigen transfer enables TRA processing and presentation by different cellular microenvironments.
Despite relevance of antigen transfer, seminal study was published, showing mTECs to form fully established central tolerance without support of additional APCs.
Antigen transfer enables indirect presentation of TRAs
First article which touches antigen transfer was published in 2004. Experiments from this study reveal that clonal deletion of autoreactive CD4+ T cells, apart from CD8+ T cells, requires indirect presentation of TRAs by bone marrow (BM) derived APCs. Direct presentation of TRAs by mTECs was shown to be insufficient in this case. Requirement of indirect presentation of some mTEC-derived TRAs in the case of recessive tolerance was perceived also by additional studies which both firstly demonstrated antigen transfer as an instrument that enables this process. Need of TRA indirect presentation is probably closely related with above mentioned "processing of TRAs by different microenvironments".
N.B.: BM derived APCs don´t express TRAs, this process is uniquely dedicated to mTECs. Exception is represented by thymic B cells which were shown to express TRAs and Aire.
Thymic dendritic cells
Systemic ablation of dendritic cells (DCs) was shown to cause fatal manifestations of autoimmunity which points to their importance in central tolerance. Indeed, as mTECs represent exclusive donors of TRAs, experiments with first antigen transfer mouse models discovered thymic dendritic cells (DCs) to be so far the only known TRAs acceptors involved in antigen transfer. Indispensability of DCs for the establishment of central tolerance was further verified by recent analysis, which revealed that DCs mediate both recessive and dominant tolerance, with preference for the latter, via presentation of more common TRAs.
Subsets
tDCs
The most efficient subset in TRA presentation and both modes of central tolerance was found to be CD8α+ thymic-derived DCs (tDCs). This subset was also shown to express XCR1 and to be attracted by mTECs via XCL1 chemokine expression. tDCs rise intrathymically and constitute approximately half of thymic DCs population.
mDCs
Sirpα+ migratory DCs (mDCs) form second subset of thymic DCs. They rise extrathymically, and were shown to present self antigens, especially blood-borne antigens, in the thymus, which they acquire in the periphery. They were also shown to be more efficient in T regulatory cells selection than clonal deletion.
pDCs
The last abundant subset of thymic DCs is represented by B220+ plasmacytoid DCs (pDCs) which also rise extrathymically and transfer peripheral antigens from the periphery to the thymus to mediate selection processes.
All these thymic DC subsets were shown to participate in antigen transfer. Nevertheless, only tDCs and mDCs were observed to utilize transferred TRAs for indirect presentation which led to the processes of central tolerance.
Mechanism
The unambiguous mechanism of the antigen transfer is still unknown. However, there are three possible ways: I. acquisition of mTEC apoptotic bodies, which could possibly be related with low mTEC lifespan II. acquisition of exosomes and III. acquisition via trogocytosis, how antigen transfer can be mediated.
There is also an evidence, that antigen transfer and therefore indirect presentation by thymic DCs are regulated by PGE activator Aire.
References
Immunology
Thymus
Molecular biology | Antigen transfer in the thymus | [
"Chemistry",
"Biology"
] | 1,207 | [
"Biochemistry",
"Immunology",
"Molecular biology"
] |
56,547,558 | https://en.wikipedia.org/wiki/Ethylestradiol | Ethylestradiol, or 17α-ethylestradiol, also known as 17α-ethylestra-1,3,5(10)-triene-3,17β-diol, is a synthetic estrogen which was never marketed. It occurs as an active metabolite of the anabolic steroids norethandrolone and ethylestrenol formed via aromatase and is believed to be responsible for the estrogenic effects of norethandrolone and ethylestrenol. The 3-methyl ether of ethylestradiol has been used as an intermediate in the synthesis of certain 19-nortestosterone anabolic steroids.
See also
List of estrogens
5α-Dihydronorethandrolone
References
Abandoned drugs
Estranes
Human drug metabolites
Synthetic estrogens
1-Ethylcyclopentanols | Ethylestradiol | [
"Chemistry"
] | 186 | [
"Chemicals in medicine",
"Drug safety",
"Human drug metabolites",
"Abandoned drugs"
] |
56,547,594 | https://en.wikipedia.org/wiki/Autographa%20californica%20multiple%20nucleopolyhedrovirus | Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a nucleopolyhedrovirus belonging to the family Baculoviridae. It has a double-stranded DNA genome that is 133,894 base pairs in length with 155 ORFs. The virus forms occluded bodies called polyhedra each containing multiple virions. AcMNPV has been shown to infect more than thirty lepidopteran hosts from 10 families.
See also
Autographa californica
References
External links
Viralzone: Betabaculovirus
ICTV
Biopesticides
Baculoviridae | Autographa californica multiple nucleopolyhedrovirus | [
"Biology"
] | 139 | [
"Virus stubs",
"Viruses"
] |
56,547,762 | https://en.wikipedia.org/wiki/Levonorgestrel%20acetate | Levonorgestrel acetate (LNG-A), or levonorgestrel 17β-acetate, also known as 3-ketonorgestimate, is a progestin which was never marketed. It is a progestogen ester and is the C17β acetate ester and a prodrug of levonorgestrel. Norgestimate is the C3 oxime of LNG-A. The drug is a minor active metabolite of norgestimate, which is a prodrug of norelgestromin and to a lesser extent of levonorgestrel and LNG-A. LNG-A has high affinity for the progesterone receptor, about 135% of that of promegestone (relative to 150% for levonorgestrel). Along with levonorgestrel butanoate, LNG-A was investigated as a hormonal contraceptive by the Population Council.
See also
List of progestogen esters
References
Abandoned drugs
Acetate esters
Ethynyl compounds
Anabolic–androgenic steroids
Enantiopure drugs
Estranes
Human drug metabolites
Enones
Sex hormone esters and conjugates
Progestogen esters
Progestogens | Levonorgestrel acetate | [
"Chemistry"
] | 265 | [
"Stereochemistry",
"Drug safety",
"Enantiopure drugs",
"Human drug metabolites",
"Chemicals in medicine",
"Abandoned drugs"
] |
56,549,915 | https://en.wikipedia.org/wiki/Baloxavir%20marboxil | Baloxavir marboxil, sold under the brand name Xofluza, is an antiviral medication for treatment of influenza A and influenza B. It was approved for medical use both in Japan and in the United States in 2018, and is taken as a single dose by mouth. It can reduce the duration of flu symptoms by about 1-2 days in some people, but can also develop selection of resistant mutants that render it ineffectual, however studies noted this was seen mostly in children that were studied.
Baloxavir marboxil was developed as a prodrug strategy, with its metabolism releasing the active agent, baloxavir acid (BXA). Baloxavir acid then functions as enzyme inhibitor, targeting the influenza virus' cap-dependent endonuclease activity, used in "cap snatching" by the virus' polymerase complex, a process essential to its life-cycle.
The most common side effects of baloxavir marboxil include diarrhea, bronchitis, nausea, sinusitis, and headache.
The US Food and Drug Administration (FDA) considers baloxavir marboxil to be a first-in-class medication.
Medical uses
Baloxavir marboxil is an influenza medication, an antiviral, for individuals who are twelve years of age or older, that have presented symptoms of this infection for no more than 48 hours. The efficacy of baloxavir marboxil administered after 48 hours has not been tested.
In October 2019, the FDA approved an updated indication for the treatment of acute, uncomplicated influenza in people twelve years of age and older at risk of influenza complications.
In November 2020, the FDA approved an updated indication to include post-exposure prevention of influenza (flu) for people twelve years of age and older after contact with an individual who has the flu.
In August 2022, the FDA approved an updated indication to include post-exposure prevention of influenza (flu) for people five years of age and older after contact with an individual who has the flu.
In the EU, baloxavir marboxil is indicated for the treatment of uncomplicated influenza and for post-exposure prophylaxis of influenza in individuals aged twelve years of age and older.
Available forms
Baloxavir marboxil is available in tablet form and as granules for mixing in water.
Resistance
In 2.2% of baloxavir recipients in the Phase II trial and in about 10% of baloxavir recipients in the Phase III trial, the infecting influenza strain had acquired resistance to the drug, due to variants of the polymerase protein displaying substitutions of isoleucine-38, specifically, the I38T, I38M, or I38F mutations. There is continuing research into and clinical concern over the resistance appearing in recipients, in response to treatment with this drug.
Contraindications
Baloxavir marboxil should not be co-administered with dairy products, calcium-fortified beverages, or laxatives, antacids, or oral supplements containing calcium, iron, magnesium, selenium, aluminum or zinc.
Side effects
Common side effects following the single dose administration of baloxavir marboxil include diarrhea, bronchitis, common cold, headache, and nausea. Adverse events were reported in 21% of people who received baloxavir, 25% of those receiving placebo, and 25% of oseltamivir.
Mechanism of action
Baloxavir marboxil is an influenza therapeutic agent, specifically, an enzyme inhibitor targeting the influenza virus' cap-dependent endonuclease activity, one of the activities of the virus polymerase complex. In particular, it inhibits a process known as cap snatching, by which the virus derives short, capped primers from host cell RNA transcripts, which it then uses for polymerase-catalyzed synthesis of its needed viral mRNAs. A polymerase subunit binds to the host pre-mRNAs at their 5' caps, then the polymerase's endonuclease activity catalyzes its cleavage "after 10–13 nucleotides". As such, its mechanism is distinct from neuraminidase inhibitors such as oseltamivir and zanamivir.
Chemistry
Baloxavir marboxil is a substituted pyridone derivative of a polycyclic family, whose chemical synthesis has been reported in a number of ways by the company discovering it, Shionogi and Co. of Japan (as well as others); the Shionogi reports have appeared several times in the Japanese patent literature between 2016 and 2019, providing insight into possible industrial synthetic routes that may be in use.
Baloxavir marboxil (BXM) is a prodrug whose active agent, baloxavir acid (BXA) is released rapidly in vivo, as the hydrolysis of baloxavir marboxil is catalyzed by arylacetamide deacetylases in cells of the blood, liver, and lumen of the small intestine. The compound numbers for baloxavir marboxil and baloxavir acid used in publications by Shionogi and others during discovery and development (prior to assignment of a United States Adopted Name (USAN)) were, respectively, S-033188 and S-033447. As reported in a review of the patent literature, the carbonic acid ester (carbonate) moiety of the prodrug—shown in the lower left-hand corner of the image above—was prepared during discovery and development research from a late stage 2-hydroxy-4-pyridone precursor by treatment with chloromethyl methyl carbonate.
History
As of September 2018, in the only report of a Phase III randomized, controlled trial, baloxavir reduced the duration of influenza symptoms of otherwise healthy participants by about one day compared with a placebo treatment group, and comparable with what was seen for an oseltamivir treatment group. On the first day after baloxavir was started in its treatment group of participants, viral loads decreased more than in participants in either the oseltamivir or placebo groups; however, after five days, the effect on viral load of the single dose of baloxavir was indistinguishable from the effect observed following the complete, 5-day regimen of oseltamivir in its treatment group.
Baloxavir marboxil was developed for the market by Shionogi Co., a Japanese pharmaceutical company, and Switzerland-based Roche AG. The names under which baloxavir marboxil and baloxavir acid appear in Shionogi research reporting are S-033188 and S-033447, respectively.
Society and culture
Legal status
Japan's Ministry of Health, Labour and Welfare (JMHLW) and the US Food and Drug Administration (FDA) approved baloxavir marboxil based on evidence of its benefits and side effects from two clinical trials in adult and pediatric participants with uncomplicated influenza (Trial 1, 1518T0821 and Trial 2, NCT02954354), involving 1119 participants. Both trials included clinical sites and participants in Japan, with Trial 2 adding clinical locations in the United States.
Baloxavir marboxil was approved for sale in Japan in February 2018. In October 2018, the FDA approved it for the treatment of acute uncomplicated influenza in people twelve years of age and older who have been symptomatic for no more than 48 hours. The FDA application of baloxavir marboxil was granted priority review in the United States, and approval of Xofluza was granted to Shionogi & Co., Ltd. in October 2018. Specifically, the FDA approved the use of baloxavir marboxil for people at high risk of developing influenza-related complications. In October 2019, the FDA approved an updated indication for the treatment of acute, uncomplicated influenza in people twelve years of age and older at risk of influenza complications. In November 2020, the FDA approved an updated indication to include post-exposure prevention of influenza (flu) for people twelve years of age and older after contact with an individual who has the flu.
Baloxavir marboxil was approved for medical use in Australia in February 2020.
The safety and efficacy of baloxavir marboxil, an antiviral drug taken as a single oral dose, was demonstrated in two randomized controlled clinical trials of 1,832 subjects where participants were assigned to receive either baloxavir marboxil, a placebo, or another antiviral flu treatment within 48 hours of experiencing flu symptoms. In both trials, subjects treated with baloxavir marboxil had a shorter time to alleviation of symptoms compared with subjects who took the placebo. In the second trial, there was no difference in the time to alleviation of symptoms between subjects who received baloxavir marboxil and those who received the other flu treatment.
The safety and efficacy of baloxavir marboxil for post-flu exposure prevention is supported by one randomized, double-blind, controlled trial in which 607 subjects, twelve years of age and older who were exposed to a person with influenza in their household, received either a single dose of baloxavir marboxil or a single dose of a placebo. Of these 607 subjects, 303 received baloxavir marboxil and 304 received the placebo. The trial's primary endpoint was the proportion of subjects who were infected with influenza virus and presented with fever and at least one respiratory symptom from day 1 to day 10. Of those who received baloxavir marboxil, 1% of subjects met these criteria, compared to 13% of subjects who received a placebo for the clinical trial.
Baloxavir marboxil was approved for medical use in the European Union in January 2021.
References
Further reading
External links
Anti–RNA virus drugs
Anti-influenza agents
Antiviral drugs
Carbonate esters
Fluoroarenes
Drugs developed by Hoffmann-La Roche
Drugs developed by Genentech
Japanese inventions
Nitrogen heterocycles
Morpholines
Prodrugs
Sulfur heterocycles
4-Pyridones
Orphan drugs | Baloxavir marboxil | [
"Chemistry",
"Biology"
] | 2,147 | [
"Antiviral drugs",
"Chemicals in medicine",
"Biocides",
"Prodrugs"
] |
56,550,351 | https://en.wikipedia.org/wiki/JNJ-39393406 | JNJ-39393406 is an experimental medication which is under development by Janssen Pharmaceutica, a division of Johnson & Johnson, for the treatment of depressive disorders and smoking withdrawal. It acts as a selective positive allosteric modulator of the α7 nicotinic acetylcholine receptor (nAChR). It does not act on the α4β2 or α3β4 nAChRs or the serotonin 5-HT3 receptor, and does not interact with a panel of 62 other receptors and enzymes. The drug has been found to lower the agonist and nicotine threshold for activation of the α7 nAChR by 10- to 20-fold and to increase the maximum agonist response of the α7 nAChR by 17- to 20-fold.
As of February 2018, JNJ-39393406 is in phase II clinical trials for both depressive disorders and smoking withdrawal. It was also under investigation for the treatment of schizophrenia and Alzheimer's disease, but development for these indications was discontinued.
See also
List of investigational antidepressants
References
Amines
Experimental antidepressants
Benzodioxoles
Experimental psychiatric drugs
Fluoroarenes
Nicotinic antagonists
Nootropics
Propionamides
4-Pyridyl compounds
Smoking cessation
Triazoles | JNJ-39393406 | [
"Chemistry"
] | 283 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
56,550,400 | https://en.wikipedia.org/wiki/NGC%20525 | NGC 525, also occasionally referred to as PGC 5232 or UGC 972, is a lenticular galaxy located approximately 95.6 million light-years from the Solar System in the constellation Pisces. It was discovered on 25 September 1862 by astronomer Heinrich d'Arrest.
Observation history
D'Arrest discovered NGC 525 using his 11-inch refractor telescope at Copenhagen. He located the galaxy's position with a total of two observations. As he also noted the mag 11-12 star just 2' northwest, his position is fairly accurate. The galaxy was later catalogued by John Louis Emil Dreyer in the New General Catalogue, where it was described as "very faint, very small, 11th or 12th magnitude star 5 seconds of time to west".
Description
The galaxy appears very dim in the sky as it only has an apparent visual magnitude of 13.3 and thus can only be observed with telescopes. It can be classified as type S0 using the Hubble Sequence. The object's distance of roughly 95.6 million light-years from the Solar System can be estimated using its redshift and Hubble's law.
See also
List of NGC objects (1–1000)
References
External links
SEDS
Lenticular galaxies
Pisces (constellation)
0525
5232
Astronomical objects discovered in 1862
Discoveries by Heinrich Louis d'Arrest | NGC 525 | [
"Astronomy"
] | 275 | [
"Pisces (constellation)",
"Constellations"
] |
56,550,745 | https://en.wikipedia.org/wiki/EVT-101 | EVT-101, also known as ENS-101, is an experimental medication which originated from Roche and is under development by Evotec AG for the treatment of major depressive disorder. It acts as a selective NMDA receptor subunit 2B (NR2B) antagonist. The drug was first claimed by Roche in 2002. By 2017, EVT-101 was in phase II clinical trials for major depressive disorder; however, development of the drug was discontinued in 2021.
See also
List of investigational antidepressants
References
Experimental antidepressants
Abandoned drugs
Imidazoles
NMDA receptor antagonists
Organofluorides
Pyridazines | EVT-101 | [
"Chemistry"
] | 136 | [
"Drug safety",
"Abandoned drugs"
] |
56,551,599 | https://en.wikipedia.org/wiki/K2-138 | K2-138, also designated EPIC 245950175 or EE-1, is a large early K-type main sequence star with a system of at least 6 planets discovered by citizen scientists. Four were found in the first two days of the Exoplanet Explorers project on Zooniverse in early April 2017, while two more were revealed in further analysis. The system is about away in the constellation Aquarius, within K2 Campaign 12.
Planetary system
K2-138 is notable for its large number of planets, all found through the efforts of citizen scientists. They are designated K2-138b, c, d, e, f, and g in order from their host star. The first five were validated by Christiansen et al., while K2-138g was noted as being a likely candidate. However, since there were only two transits of it, K2-138g could not be validated. There was a possibility that the two transits for this candidate were from two individual long-period planets. K2-138g was confirmed by follow-up studies in 2019 and 2021.
All six planets are within the super-Earth and mini-Neptune categories, with radii between about 1.6 to 3.3 . The outer five, including K2-138g, are likely small gaseous worlds with no solid surface. However, the smaller K2-138b could be rocky. The masses of the planets were initially unknown, as the data for K2-138 did not have a high enough signal-to-noise ratio for transit-timing variation (TTV) analysis. However, the Spitzer Space Telescope could be able to accurately detect TTVs and lead to the masses of the planets being calculated. Planets b through f are predicted to cause TTVs on the order of 2.5 to 7.1 minutes, for predicted masses between 4 and 7 .
The five validated planets of K2-138 are very close to the parent star and form an unbroken chain of near-3:2 resonances. Their orbital periods range from 2.35 to 12.76 days, with the sixth planet orbiting much further out with a period of about 41 days. K2-138b, c, d, e, and f are locked in several chains of three-body resonances, a feat shared by only a handful of systems, including TRAPPIST-1 and Kepler-80. Like the former, K2-138 could show the end result of slow, inward disk migration.
Spitzer observations of K2-138g were announced on the AAS Meeting #233. The iPoster shows an updated radius of K2-138g of 3.7 , making it the largest planet in the system. This result was preliminary until being confirmed in February 2021.
A team of astronomers collected 215 spectra over 79 nights with the instrument HARPS mounted on the ESO 3.6 m Telescope. With a Bayesian analysis of the K2 photometry and HARPS radial-velocities (RVs) the team were able to constrain the mass of planet b to e. The bulk densities of the planets range from Earth-like density for planet b to Neptune-like density for planet e. The masses and densities constrain the composition of the planets. They have likely rocky cores and a substantial atmospheric layer, composed of volatiles. For planets f and g this team was able to constrain the upper limit of the mass to 8.7 and 25.5 earth masses.
A paper by Acuña et al. studied the water content of the K2-138 system, assuming a volatile layer constituted of water in steam and supercritical phases. They find that the planet b has an upper water-mass-fraction of 0.7% and is a volatile-poor planet. Planet b could have formed with a thick water atmosphere that was blown away by XUV-radiation coming from the host star. A process called photoevaporation.
Planet f is possibly the most water-rich planet in the system, with an upper water-mass-fraction of 66%. The radius of planet g is larger than a planet with a water-rich composition and the researchers conclude that planet g has an atmosphere rich in hydrogen and helium and in this case the upper volatile-mass fraction would be only 5%. All planets of the system likely have a less massive core compared to earth.
K2-138 was selected as a target by ESA in the first Announcement of Opportunity (AO-1) Program of the CHEOPS mission, which was launched in December 2019. For 87.6 orbits the spacecraft will record the transits to measure TTVs of the planets. K2-138 could become a benchmark system to compare RV and TTV masses. The system is also a good candidate to search for co-orbital bodies, which are predicted to exist and to be stable in resonant chain systems like K2-138.
See also
Amateur exoplanet discoveries
K2-288Bb, another planet found by citizen scientists from Exoplanet Explorers
Kepler-86
Kepler-90
PH1b
TRAPPIST-1
References
Aquarius (constellation)
K-type main-sequence stars
J23154776-1050590
Planetary systems with six confirmed planets | K2-138 | [
"Astronomy"
] | 1,093 | [
"Constellations",
"Aquarius (constellation)"
] |
56,551,614 | https://en.wikipedia.org/wiki/Post-fire%20hillslope%20stabilization%20treatments | Post-fire hillslope stabilization treatments are treatments aimed at stabilizing fire-affected slopes by counteracting the negative impact of fire on vegetation and soil properties. The final objective of these treatments is reducing the risk of catastrophic runoff and erosion events and protecting valued resources downhill. Post-fire hillslope stabilization treatments are also called post-fire mitigation treatments and emergency stabilization treatments.
Vegetation fires usually partially or totally consume the canopy, above-ground organic residue (litter), fine roots, and soil organic compounds, reducing soil protection, enhancing soil water repellency, and compromising soil stability. The combined effect of fire and the occurrence of heavy rainfall in the post-fire season can lead to catastrophic hydrologic and erosion events with severe impacts on population and valued resources downhill such as housing, infrastructures, water supply systems, and critical habitats.
For example, high intensity rainfall after the Thomas Fire in California (USA) led to catastrophic floods and debris flows in 2018 with 20 people dead, 300 houses destroyed, and critical infrastructures severely affected. Stabilization treatments are part of the Burned Area Emergency Response (BAER) programme implemented by the US Forest Service and Department of Interior (USA) and similar programmes such as the Rapid Response Assessment Team (RRAT) in Australia conducted in many other fire-prone regions.
Classification of post-fire hillslope stabilization treatments
The design of the hillslope stabilization treatments are aimed at:
Counteracting the effect of fire on the soil protection provided by the vegetation and surface cover: treatments such as seeding and mulching are aimed at reducing runoff and erosion by providing protection to the soil surface. They mimick above ground organic layers that protect the soil against the raindrop impact and absorb rain water, decreasing runoff volume and velocity.
Counteracting the effect of fire on specific soil properties involved in the runoff and erosion processes: treatments that seek for offsetting fire effects on soils such as enhanced soil water repellency (surfactants) or decreased soil aggregation (flocculants). These products can be applied alone or combined with other stabilization treatments to increase their effectiveness.
Reducing slope length: treatments such as the erosion barriers are intended to reduce the amount of sediments that reach values-at-risk downhill by reducing the slope length and, thus, runoff velocity and erosion potential. They also create mini-dams that hold the runoff, promote infiltration, and sediments settling.
Types, selection, and implementation of post-fire treatments
The selection of hillslope stabilization treatments should consider three key elements: (i) the effectiveness of the treatment, (iii) the cost of production and transport, and (i) the values-at-risk to be protected The most cost-effective treatment might not be adequate to protect critical values-at-risk whereas the treatment with the highest effectiveness and cost could not be suitable to treat large areas if the cost of repairing or replacing values-at-risk is low. Since the highest risk of catastrophic events happens during the first year after the fire, the implementation of any emergency treatment must be conducted quickly after the fire.
Seeding: Seeds of native or non-native grasses (usually non-reproducing annuals to avoid negative interactions with native flora and alteration of local biodiversity) are manually or aerially applied over the burned area to promote a rapid vegetation establishment that provides ground cover and increase soil stability with their shallow root system. Seeding have been the post-fire hillslope mitigation treatment most frequently used in the world and mainly in the USA (in the 1970s and 1980s 75% of the burned areas treated in the USA were seeded ). However, negative side-effects such as the potential introduction of non-native species, negative interactions with the recover of native vegetation, and its low efficiency during the first year after the fire before their germination contributed to the reduction of its use (in the 2000s only 30% of the burned areas treated in the USA were seeded ).
Erosion barriers: Contour-felled logs or straw wattles became popular in the USA during the 1990s coinciding with the decrease of seeded areas. Felled-logs or straw wattles are placed on the hillslope contour and aim to reduce runoff velocity and create areas where the runoff water can infiltrate, and the sediment settle. Recent studies however, have showed the low effectiveness of this technique for high intensity rainfall, when the holding capacity is easily exceeded, or their holding capacity is reduced by sediments from previous erosion events. Additionally, a poor design and installation (gaps between the log and the soil surface or not on contour with a slope to one end) can lead to increased erosion due to the concentration of the runoff in lowest end of the barrier. Despite these recent insights, log barriers are still extensively applied in Mediterranean countries such as Spain.
Mulching: Covering the soil surface with a material that provides protection against raindrop impact, retains water, and reduce runoff velocity. The material most commonly used is agricultural straw, whose application reached in the 2000s 18% of the burned areas treated in the USA. This extensive use is due to its high effectiveness but also the development of its aerial application that reduced the application costs and made it viable in inaccessible areas. An alternative to straw mulching is the wood-based mulch using wood chips, wood shreds, and wood strand but also pine needles and forest residues. Although marginally used before the 2010s, wood-based mulching is becoming popular since it prevents side-effects of agricultural straw such as the introduction of non-native species and invasive weeds, its longer longevity, and stability to wind. Additionally, wood-based mulches can be produced locally from burned or green trees, reducing transport costs.
Chemical treatments: Tackifiers, fertilizers, and flocculants are used as stand-alone emergency treatments or in combination with other treatment to provide increased soil stability to reduce runoff and erosion. Anionic polyacrylamide (PAM), a synthetic petroleum by-product, is a flocculant that is applied as pellets or in solution to the soil surface in fire-affected areas. PAM binds soil particles, increase soil stability and infiltration, and reduce soil erosion. However, studies on their effectiveness in fire-affected areas are inconclusive or show no significant effect on runoff and erosion
Combined treatments: Seeding has been frequently combined with fertilizers to increase the viability of the seedlings. Seeds have been coated with surfactant to reduce fire-induced soil water repellency and increase water availability. Organic fibres (wood shreds, paper, cotton and flax) have been mixed with seeds, fertilizers and tackifiers to produce hydromulches. Although combined treatments can have higher effectiveness, the associated increase in production or transport costs can make their application less cost-effective and only viable to provide additional protection to critical values-at-risk.
References
Slope landforms
Landslide analysis, prevention and mitigation
Forest management
Emergency management
Wildfire ecology
Risk management
Soil
Erosion | Post-fire hillslope stabilization treatments | [
"Environmental_science"
] | 1,437 | [
"Environmental soil science",
" prevention and mitigation",
"Landslide analysis"
] |
56,551,950 | https://en.wikipedia.org/wiki/BaZnGa | BaZnGa (barium zinc gallide) is a ternary compound of barium, zinc, and gallium that was inspired by the saying "Bazinga!" from Sheldon Cooper on The Big Bang Theory television series. It is a poor metal. BaZnGa crystals can be grown by adding gallium to a BaZn eutectic at 800° C and then cooling to 400 °C. Hot liquid BaZn is hard to handle because zinc vapourises and barium reacts with air. Next, centrifuging filtration removes the crystals of BaZnGa from the liquid BaZn. The crystals have space group I4/mmm tI36 with a=6.3652 and c=25.593 Å. The unit cell volume is 1036.9 Å3, with 12 formula units per cell. The electrical resistivity at room temperature is 2.5×10−4 Ohm·cm.
Various merchandise has been produced with periodic table like entries of Ba, Zn & Ga, including clothing and mugs.
A substance with a similar looking formula BaZnGa10O17, a barium zinc gallate, is a barium ion conductor.
References
External links
Gallium alloys
Barium compounds
Zinc alloys
The Big Bang Theory | BaZnGa | [
"Chemistry"
] | 262 | [
"Alloys",
"Zinc alloys",
"Gallium alloys"
] |
70,721,631 | https://en.wikipedia.org/wiki/Activated%20protein%20C%E2%80%93protein%20C%20inhibitor | Activated protein C–protein C inhibitor (APC-PCI) is a complex of activated protein C (APC) and protein C inhibitor (PCI). It has been measured in coagulation testing to evaluate coagulation, thrombosis, and other cardiovascular complications. It is a marker of thrombin generation and indicates hypercoagulability. The half-life of APC-PCI is either 40 minutes or 140minutes.
Ethinylestradiol-containing birth control pills have been found to increase levels of APC-PCI to a similar degree as thrombin–antithrombin complex (TAT) and to a greater extent than D-dimer. However, only APC-PCI was able to differentiate between a second- and third-generation birth control pill.
Another complex related to APC-PCI is the activated protein C–α1-antitrypsin (APCAT) complex.
References
Coagulation system
Protein complexes | Activated protein C–protein C inhibitor | [
"Chemistry",
"Biology"
] | 209 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry"
] |
70,721,697 | https://en.wikipedia.org/wiki/Neodymium%20tantalate | Neodymium tantalate is an inorganic compound with the chemical formula NdTaO4. It is prepared by reacting neodymium oxide and tantalum pentoxide at 1200 °C. It reacts with a mixture of tantalum pentoxide and chlorine gas at high temperature to obtain Nd2Ta2O7Cl2. It is ammonolyzed at high temperature to obtain oxynitrides of Nd-Ta.
Properties
Neodymium tantalate forms violet crystals of the monoclinic system, with space group I 2/a, cell parameters a = 0.55153 nm, b = 1.12388 nm, c = 0.51184 nm, β = 95.731°, Z = 4.
There is a metastable high-pressure phase of the monoclinic system, space group P 21/c, cell parameters a = 0.75920 nm, b = 0.54673 nm, c = 0.77022 nm, β = 100.032°, Z = 4.
Neodymium tantalate is insoluble in water.
See also
Neodymium
Tantalum
Tantalate
References
External links
Tantalates
Neodymium(III) compounds | Neodymium tantalate | [
"Chemistry"
] | 267 | [
"Tantalates",
"Salts"
] |
70,721,775 | https://en.wikipedia.org/wiki/6-Bromotryptamine | 6-Bromotryptamine is a substituted tryptamine that is a marine natural product.
See also
5,6-Dibromotryptamine
5,6-Dibromo-N-methyltryptamine
5-Bromo-DMT
References
Tryptamine alkaloids
Bromoarenes | 6-Bromotryptamine | [
"Chemistry"
] | 66 | [
"Tryptamine alkaloids",
"Alkaloids by chemical classification"
] |
70,721,861 | https://en.wikipedia.org/wiki/5%2C6-Dibromotryptamine | 5,6-Dibromotryptamine is a substituted tryptamine and indolic alkaloid found in some marine sponges such as Hyrtios sp. found in the South Pacific area. 5,6-Dibromotryptamine is potentially an anti bacterial and anti cancer agent.
See also
5,6-Dibromo-N-methyltryptamine
6-Bromotryptamine
5-Bromo-DMT
References
Tryptamine alkaloids
Bromoarenes | 5,6-Dibromotryptamine | [
"Chemistry"
] | 106 | [
"Tryptamine alkaloids",
"Alkaloids by chemical classification"
] |
70,721,974 | https://en.wikipedia.org/wiki/Neodymium%20perrhenate | Neodymium perrhenate is an inorganic compound with the chemical formula Nd(ReO4)3, which exists in anhydrous and tetrahydrate. It can be obtained by reacting excess neodymium oxide with 240 g/L perrhenic acid solution. In its solution, NdReO42+ and Nd(ReO4)2+ can be observed with stability constants of 16.5 and 23.6, respectively.
Nd4Re6O19 can be obtained by reacting neodymium perrhenate and NdRe2 at high temperature.
See also
Neodymium
Rhenium
Perrhenate
References
Perrhenates
Neodymium(III) compounds | Neodymium perrhenate | [
"Chemistry"
] | 151 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
70,722,235 | https://en.wikipedia.org/wiki/Necromeny | Necromeny is a symbiotic relationship where an animal (typically a juvenile stage nematode) infects a host and waits inside its body until its death, at which point it develops and completes its life-cycle on the cadaver, feeding on the decaying matter and the subsequent bacterial growth. As the necromenic animal benefits from the relationship while the host is unharmed, it is an example of commensalism.
An example of this is the facultative parasitic nematode species, Phasmarhabditis hermaphrodita. It can kill certain types of slugs and snails (Arionidae, Milacidae and Limacidae), but for more resistant species, it lies dormant until the host dies naturally. Conversely, entomopathogenic nematodes (or EPNs) such as Steinernema and Heterorhabditis also thrive on the decaying corpses of their hosts, but they seek out to actively kill their hosts through the release of a symbiotic bacterium (Xenorhabdus/Photorhabdus and Paenibacillus, respectively).
Necromeny has also been observed in mites, including species of Histiostoma and Sancassania.
References
Parasitism
Parasitology
Ecology
Disease ecology | Necromeny | [
"Biology"
] | 274 | [
"Parasitism",
"Symbiosis",
"Ecology"
] |
70,722,379 | https://en.wikipedia.org/wiki/Praseodymium%20arsenate | Praseodymium arsenate is the arsenate salt of praseodymium, with the chemical formula of PrAsO4. It has good thermal stability. Its ferroelectric transition temperature is 52°C.
Preparation
Praseodymium arsenate be prepared by reacting sodium arsenate (Na3AsO4) and praseodymium chloride (PrCl3) in a solution:
Na3AsO4 + PrCl3 → 3 NaCl + PrAsO4↓
The product can also be obtained by reacting praseodymium(III,IV) oxide and diammonium hydrogen arsenate in hot dilute nitric acid in a stoichiometric ratio.
References
Praseodymium(III) compounds
Arsenates | Praseodymium arsenate | [
"Chemistry"
] | 165 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
70,722,705 | https://en.wikipedia.org/wiki/Delphinella%20deviata | Delphinella deviata is a species of fungus in the family Dothioraceae.
References
External links
Fungi described in 1962
Dothideales
Fungus species | Delphinella deviata | [
"Biology"
] | 32 | [
"Fungi",
"Fungus species"
] |
70,722,728 | https://en.wikipedia.org/wiki/Delphinella%20peckii | Delphinella peckii is a species of fungus in the family Dothioraceae. It was transferred to the genus Delphinella from the genus Mycosphaerella in 1986.
References
Fungi described in 1897
Fungi of Canada
Dothideales
Taxa named by Gustav Lindau
Fungus species | Delphinella peckii | [
"Biology"
] | 59 | [
"Fungi",
"Fungus species"
] |
70,722,748 | https://en.wikipedia.org/wiki/Delphinella%20balsameae | Delphinella balsameae is a species of fungus in the family Dothioraceae. It is a known plant pathogen, reported to cause blight in Siberian fir in Russia, balsam fir, white fir and subalpine fir in North-America.
References
External links
Fungi described in 1962
Dothideales
Fungus species | Delphinella balsameae | [
"Biology"
] | 68 | [
"Fungi",
"Fungus species"
] |
70,722,797 | https://en.wikipedia.org/wiki/Delphinella%20abietis | Delphinella abietis is a species of fungus in the family Dothioraceae. It has been reported from western Norway where it infects needles and sometimes shoots of various fir species. These include subalpine fir, Nordmann fir including Turkish fir, Siberian fir and noble fir.
References
External links
Fungi described in 1962
Fungi of the United Kingdom
Fungi of Sweden
Dothideales
Fungus species | Delphinella abietis | [
"Biology"
] | 82 | [
"Fungi",
"Fungus species"
] |
70,723,319 | https://en.wikipedia.org/wiki/H3T3P | H3T3P is an epigenetic modification to the DNA packaging protein histone H3. It is a mark that indicates the phosphorylation the 3rd threonine residue of the histone H3 protein.
Pre-existing vs newly generated H3 is distinguished by phosphorylation at threonine 3. H3T3P separates sister chromatids enriched with diverse pools of H3 in order to coordinate asymmetric segregation of "old" H3 into germ stem cells and that male germline activity requires tight regulation of H3T3 phosphorylation.
Nomenclature
The name of this modification indicates the protein phosphorylation of threonine 3 on histone H3 protein subunit:
Serine/threonine/tyrosine phosphorylation
The addition of a negatively charged phosphate group can lead to major changes in protein structure, leading to the well-characterized role of phosphorylation in controlling protein function. It is not clear what structural implications histone phosphorylation has, but histone phosphorylation has clear functions as a post-translational modification.
Effect of modification
How stem cells preserve their identity via numerous divisions is unknown. Adult stem cells divide asymmetrically to produce a self-renewing stem cell and a daughter cell that will differentiate later. Many human disorders, ranging from cancer to tissue dystrophy to infertility, are caused by a disruption in this balance.
Pre-existing vs newly generated H3 is distinguished by phosphorylation at threonine 3. H3T3P separates sister chromatids enriched with diverse pools of H3 in order to coordinate asymmetric segregation of "old" H3 into germ stem cells and that male germline activity requires tight regulation of H3T3 phosphorylation.
Histone modifications
The genomic DNA of eukaryotic cells is wrapped around special protein molecules known as histones. The complexes formed by the looping of the DNA are known as chromatin.
Post-translational modification of histones such as histone phosphorylation has been shown to modify the chromatin structure by changing protein:DNA or protein:protein interactions. Histone post-translational modifications modify the chromatin structure. The most commonly associated histone phosphorylation occurs during cellular responses to DNA damage, when phosphorylated histone H2A separates large chromatin domains around the site of DNA breakage. Researchers investigated whether modifications of histones directly impact RNA polymerase II directed transcription. Researchers choose proteins that are known to modify histones to test their effects on transcription, and found that the stress-induced kinase, MSK1, inhibits RNA synthesis. Inhibition of transcription by MSK1 was most sensitive when the template was in chromatin, since DNA templates not in chromatin were resistant to the effects of MSK1. It was shown that MSK1 phosphorylated histone H2A on serine 1, and mutation of serine 1 to alanine blocked the inhibition of transcription by MSK1. Thus results suggested that the acetylation of histones can stimulate transcription by suppressing an inhibitory phosphorylation by a kinase as MSK1.
Mechanism and function of modification
Phosphorylation introduces a charged and hydrophilic group in the side chain of amino acids, possibly changing a protein's structure by altering interactions with nearby amino acids. Some proteins such as p53 contain multiple phosphorylation sites, facilitating complex, multi-level regulation. Because of the ease with which proteins can be phosphorylated and dephosphorylated, this type of modification is a flexible mechanism for cells to respond to external signals and environmental conditions.
Kinases phosphorylate proteins and phosphatases dephosphorylate proteins. Many enzymes and receptors are switched "on" or "off" by phosphorylation and dephosphorylation. Reversible phosphorylation results in a conformational change in the structure in many enzymes and receptors, causing them to become activated or deactivated. Phosphorylation usually occurs on serine, threonine, tyrosine and histidine residues in eukaryotic proteins. Histidine phosphorylation of eukaryotic proteins appears to be much more frequent than tyrosine phosphorylation. In prokaryotic proteins phosphorylation occurs on the serine, threonine, tyrosine, histidine or arginine or lysine residues. The addition of a phosphate (PO43-) molecule to a non-polar R group of an amino acid residue can turn a hydrophobic portion of a protein into a polar and extremely hydrophilic portion of a molecule. In this way protein dynamics can induce a conformational change in the structure of the protein via long-range allostery with other hydrophobic and hydrophilic residues in the protein.
Epigenetic implications
The post-translational modification of histone tails by either histone-modifying complexes or chromatin remodeling complexes is interpreted by the cell and leads to complex, combinatorial transcriptional output. It is thought that a histone code dictates the expression of genes by a complex interaction between the histones in a particular region. The current understanding and interpretation of histones comes from two large scale projects: ENCODE and the Epigenomic roadmap. The purpose of the epigenomic study was to investigate epigenetic changes across the entire genome. This led to chromatin states, which define genomic regions by grouping different proteins and/or histone modifications together.
Chromatin states were investigated in Drosophila cells by looking at the binding location of proteins in the genome. Use of ChIP-sequencing revealed regions in the genome characterized by different banding. Different developmental stages were profiled in Drosophila as well, an emphasis was placed on histone modification relevance. A look in to the data obtained led to the definition of chromatin states based on histone modifications. Certain modifications were mapped and enrichment was seen to localize in certain genomic regions.
The human genome is annotated with chromatin states. These annotated states can be used as new ways to annotate a genome independently of the underlying genome sequence. This independence from the DNA sequence enforces the epigenetic nature of histone modifications. Chromatin states are also useful in identifying regulatory elements that have no defined sequence, such as enhancers. This additional level of annotation allows for a deeper understanding of cell specific gene regulation.
Methods
The histone mark can be detected in a variety of ways:
1. Chromatin Immunoprecipitation Sequencing (ChIP-sequencing) measures the amount of DNA enrichment once bound to a targeted protein and immunoprecipitated. It results in good optimization and is used in vivo to reveal DNA-protein binding occurring in cells. ChIP-Seq can be used to identify and quantify various DNA fragments for different histone modifications along a genomic region.
2. Micrococcal Nuclease sequencing (MNase-seq) is used to investigate regions that are bound by well-positioned nucleosomes. Use of the micrococcal nuclease enzyme is employed to identify nucleosome positioning. Well-positioned nucleosomes are seen to have enrichment of sequences.
3. Assay for transposase accessible chromatin sequencing (ATAC-seq) is used to look in to regions that are nucleosome free (open chromatin). It uses hyperactive Tn5 transposon to highlight nucleosome localisation.
References
Epigenetics
Post-translational modification | H3T3P | [
"Chemistry"
] | 1,646 | [
"Post-translational modification",
"Gene expression",
"Biochemical reactions"
] |
70,727,739 | https://en.wikipedia.org/wiki/PPO%20inhibitor | A PPO inhibitor may inhibit two unrelated enzymes abbreviated "PPO". They are:
Protoporphyrinogen oxidase inhibitors Used as herbicides
Polyphenol oxidase inhibitors
Biochemistry terminology | PPO inhibitor | [
"Chemistry",
"Biology"
] | 43 | [
"Biochemistry",
"Biochemistry terminology"
] |
70,728,182 | https://en.wikipedia.org/wiki/16%20Delphini | 16 Delphini is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.54, making it faintly visible to the naked eye. The star is relatively close at a distance of 198 light years but is receding with a poorly constrained radial velocity of .
16 Delphini is a chemically peculiar A-type main-sequence star with a stellar classification of A5 V. It has twice the Sun's mass, 1.9 times it's radius, and shines at . This yields an effective temperature of 9,039 K, giving it a white glow. 16 Del is 400 million years old – 56.5% through its main sequence lifetime – and spins rapidly with a projected rotational velocity of .
16 Del has a companion that was first discovered by John Herschel and was even noted to be a spectroscopic binary. It is now considered to be a single star.
References
Delphinus
A-type main-sequence stars
Delphini, 16
199254
103298
8012
BD+12 4501 | 16 Delphini | [
"Astronomy"
] | 218 | [
"Delphinus",
"Constellations"
] |
70,728,366 | https://en.wikipedia.org/wiki/Morphism%20of%20finite%20type | In commutative algebra, given a homomorphism of commutative rings, is called an -algebra of finite type if is a finitely generated as an -algebra. It is much stronger for to be a finite -algebra, which means that is finitely generated as an -module. For example, for any commutative ring and natural number , the polynomial ring is an -algebra of finite type, but it is not a finite -algebra unless = 0 or = 0. Another example of a finite-type homomorphism that is not finite is .
The analogous notion in terms of schemes is: a morphism of schemes is of finite type if has a covering by affine open subschemes such that has a finite covering by affine open subschemes of with an -algebra of finite type. One also says that is of finite type over .
For example, for any natural number and field , affine -space and projective -space over are of finite type over (that is, over ), while they are not finite over unless = 0. More generally, any quasi-projective scheme over is of finite type over .
The Noether normalization lemma says, in geometric terms, that every affine scheme of finite type over a field has a finite surjective morphism to affine space over , where is the dimension of . Likewise, every projective scheme over a field has a finite surjective morphism to projective space , where is the dimension of .
References
Algebraic geometry
Morphisms | Morphism of finite type | [
"Mathematics"
] | 312 | [
"Functions and mappings",
"Mathematical structures",
"Mathematical objects",
"Fields of abstract algebra",
"Category theory",
"Mathematical relations",
"Algebraic geometry",
"Morphisms"
] |
70,729,280 | https://en.wikipedia.org/wiki/Exiguobacterium%20undae | Exiguobacterium undae is a species of Bacilli. Its discovery was published in the International Journal of Systematic and Evolutionary Microbiology (Frühling et al., 2002). This species has the ability to metabolize arabinose, cellulose, fructose, and glucose. It may undergo fermentation by utilizing D-glucose, D-mannitol, D-ribose, and glycogen (Bacdive 2021). E. undae is motile and it contains peritrichous flagella.
Physiology
E. undae was first sampled from the surface of a garden pond in Wolfenbuttel, Lower Saxony, Germany (Frühling et al., 2002). The pond water containing this species was streaked by researchers onto glucose sulfide (GS) medium (DSMZ 851). Four strains, L1-L4, were acquired from the garden pond and successfully isolated in tryptone soy agar at room temperature (Frühling et al., 2002). E. undae is a Gram-positive, rod-shaped bacterium that is motile and yellow-orange in color (Bacdive 2021). It is facultatively anaerobic and catalase- and oxidase-positive (Frühling et al., 2002). After 2 days of incubation at 25°C, 2-3 mm surface colonies of the E. undae can form on tryptone soy agar; the colonies are convex, entire, and shiny (Frühling et al., 2002).
Ecology
The genus Exiguobacteria has been detected from water and soil samples on all continents. Strain DR14 of this species was isolated from Dadri wetlands in India (Chauhan et al., 2018). Certain strains have been shown to be able to grow in soils that contain high concentrations of cadmium and immobilize it, which displays some potential for their use in bioremediation (Kumar et al., 2014).
Special features
E. undae strain DR14 have the ability to degrade polystyrene (PS) and use it as a carbon source by initiating biofilm formation (Chauhan et al., 2018). Researchers incubated the bacterium in the presence of PS for 20 days and demonstrated that the PS had been biodegraded by measuring the water contact angle of the material after incubation (Chauhan et al., 2018). This finding suggests that DR14 can change the surface characteristics of PS to make it easier to colonize and metabolize.
References
Bacillaceae
Bacteria described in 2002
Plastivores | Exiguobacterium undae | [
"Biology"
] | 561 | [
"Organisms by adaptation",
"Plastivores"
] |
70,729,648 | https://en.wikipedia.org/wiki/Anaeromyces%20robustus | Anaeromyces robustus is a fungal microorganism that lives in the gut rumen of many ruminant herbivores such as cows and sheep. Previously thought to be protozoa from their flagellated zoospores, they are biomass degraders, breaking down carbohydrates and plant materials from the food the animal ingests. This fungus, therefore, is anaerobic and lives without oxygen. Gut fungi are dramatically outnumbered by other organisms in the microbiome; they are members of the gut microbiome in ruminants and hindgut fermenters and play a key role in digestion.
Taxonomy
Initially, this fungal species was isolated from sheep fecal material in the Santa Barbara Zoo in 2017. It fit into the division of Neocallimastigomycota, as all species within this order live in the gut rumen of large herbivores.
Description
A. robustus is characterized by its long hyphal segments and its ability to reproduce asexually from flagellated zoospores. With the production of zoospores, this fungus's lifecycle is very representative of species of fungi from the phylum Chitridiomycota. This fungus has polycentric sporangia development as many sporangia develop throughout the thallus. With this, there is also nucleus movement through many repeated divisions through the rhizoids.
Ecology
This fungus helps animals with the digestion of plant materials. Certain enzymes produced from A. robustus have significantly more enzymatic activity when compared to bacteria and other organisms inside of gut rumen. There is a species of archaea, Methanobacterium bryantii, that increases the fungus's ability to break down carbohydrates by increasing the CAZyme production of the fungus. When exposed to harmful gut bacteria, rumen fungi are known to produce their own antibiotics, making them potentially useful when looking into synthesizing new antibiotics.
Horizontal gene transfer (HGT) has been thought to have occurred between fungal ruminants, like A. robustus, and bacteria that are found in the same environment. Through this gene transfer, it is thought that it has adopted some of the biosynthetic genes the fungus uses to break down carbohydrates from certain bacteria.
Anaerobic gut fungi can create a compound called styrylprone that is typically found in other mushrooms that can be used for herbal medicine. This compound has similarities to antioxidants that are found in a plethora of plants.
Geographical distribution
The fungus was found in the United States and around the country in many large ruminants and hind-gut fermenters. One reference states that A. robustus and other ruminomyces were found in fecal samples from many cows and goats in Oklahoma. Another reference states the fungus was found in fecal samples of sheep in the Santa Barbara Zoo in 2017.
In rumen
Ruminant animals such as cattle, sheep, and goats have a specialized four-chamber stomach, the largest chamber of which is known as the rumen. Rumen contains a plethora of microorganisms that are responsible for the breakdown of fibrous materials. This symbiotic relationship allows ruminants to utilize nutrients from plants that other species are unable to digest.
Anaeromyces robustus is found in relatively low quantities compared to many bacterial microorganisms within the rumen; however, this fungus has been shown to play a significant role in ruminant digestion through the production of xylanase. A large proportion of plants have a compound known as xylan within the hemicellulose in their cell walls. This compound can make it difficult for animals to utilize the nutrients within the cell. The xylanase, produced by Anaeromyces robustus, is able to efficiently break down the xylan within plant cell walls, allowing ruminant animals to utilize the nutrients in fibrous feedstuffs. Little is known about its genomics or the secondary metabolites it is responsible for producing. Some sources have hypothesized that this fungus produces metabolites within the rumen that help the microorganism survive in an environment where it is largely outnumbered by bacteria.
Use in bread making
The gene within the fungus that produces xylanase has been identified in the lab for potential use in food production. The introduction of this gene into flour used in baking has been shown to make the bread softer. The fermentation temperatures required by the fungus are shown to closely match those required by yeast, another common component in bread.
References
Microorganisms
Fungi described in 2016
Fungi of the United States
Neocallimastigomycota
Fungi without expected TNC conservation status
Fungus species | Anaeromyces robustus | [
"Biology"
] | 986 | [
"Fungi",
"Microorganisms",
"Fungus species"
] |
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