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60,914,866 | https://en.wikipedia.org/wiki/Vadim%20Utkin | Vadim Ivanovich Utkin (; 30 October 1937 – 18 September 2022) was a Russian-American control theorist, electrical engineer and a professor of Electrical Engineering and Mechanical Engineering at the Ohio State University. He is best known for being one of the originators of Sliding Mode Control and Variable Structure Systems, which have become fundamental concepts in the field of nonlinear control (e.g. robust control).
Biography
Utkin was born in Moscow, Soviet Union. He was with the Institute of Control Sciences from 1960 to 1994, where he served as its Head of Discontinuous Control Systems Laboratory from 1973 to 1994. He joined the Ohio State University in 1994 as the Ford Chair of Electromechanical Systems, and was the first professor to hold this distinction until 2002.
He was an IEEE Fellow, and he has been the recipient of awards such as the Lenin Prize and the Humboldt Prize. He also holds honorary doctorates from the University of Sarajevo and Rovira and Vergil University.
Selected works
Sliding Modes and their Applications in Variable Structure Systems. Mir, Moscow, 1978.
Sliding Modes in Control and Optimization, Springer Verlag, 1992.
Sliding Mode Control in Electro-Mechanical Systems, Taylor & Frencis. 1st edition 1999, 2nd edition 2009.
References
1937 births
2022 deaths
Control theorists
Fellows of the IEEE
Ohio State University faculty
Russian emigrants to the United States
Scientists from Moscow | Vadim Utkin | [
"Engineering"
] | 281 | [
"Control engineering",
"Control theorists"
] |
60,915,152 | https://en.wikipedia.org/wiki/Metarhizium%20pinghaense | Metarhizium pinghaense is a species of entomopathogenic fungus in the family Clavicipitaceae. Some authorities have it as a synonym of Metarhizium anisopliae. DNA studies show that it is a good species, with strong bootstrap support.
Researchers in Burkina Faso have created a strain of M. metarhizium genetically engineered to produce the venom of an Australian funnel-web spider; exposure to the fungus caused populations of anopheles mosquitoes, which spread malaria, to crash by 99% in a controlled trial.
References
Clavicipitaceae
Hypocreales genera
Biological pest control
Fungi described in 1996
Fungus species | Metarhizium pinghaense | [
"Biology"
] | 140 | [
"Fungi",
"Fungus species"
] |
60,915,198 | https://en.wikipedia.org/wiki/Compensatory%20Afforestation | Compensatory Afforestation (CA) is defined as the process of afforestation, and associated regeneration activities are done to compensate for destroyed forest land that has been diverted to non-forest activities. In this context, non-forest activities mean the clearing of a forest or just a small part for the following purposes: Coffee cultivation, rubber, tea, plants with oil, medicinal plants or gardening crops. This may be for the purpose of personal use or for business use—or any other purpose other than the reforestation of the forest.
Even though the forests are cut down, this process of Compensatory Afforestation ensures that the forest is still put into good use.
Compensatory afforestation is also a means of creating non-forest land-use replacements. Non-forest purposes include the activities, for example, cultivation or redevelopment in an area that had forests previously. Mostly, Compensatory afforestation is mainly carried out for the purpose of agriculture or any other activity other than industrial use on the piece of land. Compensatory Afforestation is not applied to activities of management of the wildlife, development activities, conservation of the environment and management of the forest, for example, fencing, construction of bridges, and channels construction. The organization that is backing the project is the one that incurs all the cost of compensating a forest.
Countries and Regions
America
America's forest cover as of 2010 was 304.022 million hectares, which represents 33% of the country's geographical land Between 1990 and 2010, America was losing 384,350 hectares of forest cover annually. This resulted to the establishment of programs like Forest Service Reforestation, Stewardships Incentives Program, and the Forestry Incentives Program which were tasked with the responsibilities of overseeing the creation of new forests to help replace those wasted for industrial and human settlement purposes. Further, the US Code, Title 16, Chapter 2 of National Forests calls for the establishment of new National Forests by the American Forest Service to help minimize the impacts of deforestation due to human activities. Some other acts include the 1973 Endangered Species Act and the Clean Water Act.
Australia
Before British settlement in Australia in 1788, forests covered 9% of the entire country and they were further destroyed by human activities like farming, grazing, and human activities such as human settlement. In Australia, afforestation endeavours are conducted by the National Tree Program in conjunction with the National Coordination Committee, which was created in 1987. The endeavours of the former include supplying seedlings to members of society to create forests in society. The committee compensates landowners which resulted in the planting of 15.9 million trees in Australia. Some other initiatives include the One Billion Trees Program as well as the Save the Bush Program which oversees the creation of forests in the nation.
China
The forest area in China is 175 million hectares, and annual timber accumulation is 12.5 billion cubic meters; the World Bank ranks China as the fifth country when it comes to forest-deficiency. However, the government has put in place measures for compensatory afforestation to meet the tremendous economic growth characterized by vast industrialization. In 1999 there was a compensation afforestation scheme in Shanxi, Gansu, and Sichuan where 14 million hectares were planted to compensate for the cultivated forests and human settlements. In 2000, the State Council approved the project of Six National Key Forest; the subject of Natural Forest Protection, the Desertification and Dust Storms Control Program, the project of Sloping Land Conversion, the Forest Shelterbelt Development Program, and the subject of Wildlife Conservation and Nature Reserves Development. Moreover, in 2018 China's State Forestry Administration head Zhang Jianlong announced that China would grow 6.6 million hectares with most of them being in the Xiongan Development Zone and Hebei to help counter for the forests destroyed for industrial growth and human settlement.
India
In the year 2012, the Supreme Court of India stated the misuse of money that is being composed for afforestation and the method in which funds are not being completely used for their purpose. In relation to the failure of the way the funds are being used misappropriate, Indian High Court gave an order for the creation of a better pool of funds and therefore, a new organization called the Compensatory Afforestation Management and Planning Authority (CAMPA) was established. The offices of the state can got 10% funds from National CAMPA for the conservation of forests and the purpose of afforestation. But as the funds that the offices received was still misappropriate used, the CAMPA act was implemented by the Indian government in the year 2015 to monitor and regulate how the funds are being used. CAMPA act, refers to a notice in the Indian legislation whose main aim is to provide appropriate mechanism that is institutional, at the center and in every Union and State Territory, so as to ensure that there is proper utilization in transparent and efficient amounts of manner that has been put in lands in the forest diverted to land that is used for non-forest use. By the year 2019, offices had been started to be set up of the National CAMPA oversees proper utilization of funds. But some scholars still argue that some part of the fund needs to be paid to the aboriginals of the area.
U.K.
The effects of vast human urbanization characterized by industrial growth resulted to reduction of forest cover by approximately 4% resulting to the creation of the Forestry Act legislated in 1951 which required wood owners to obtain licenses before cutting down trees. In 1988, the Woodland Grant Scheme was introduced to oversee the creation of new forests and resulted to the establishment of 700 hectares in the U.K. In fact, in 2018, the government announced that it would create new forests in various places like the Liverpool and the city of Hull.
Progress
According to Global Forest Watch, the forest cover created due to compensatory afforestation globally since 2001 to 2018 increased by 5.4%. Apparently, compensatory afforestation arose as a result of vast deforestation rates in various parts of the world. Precisely, it began in India in 1980 through the Forest Conservation Act which required the acquisition of forest land and the requirement for compensatory afforestation as per the government's requirements. This was later revolutionized by the adoption of the net present value concept for the forests from 2002 since the Supreme Court in India believe that compensatory afforestation was not fully sufficient to substitute for the natural forests destroyed. This resulted to the formation of the National Compensatory Afforestation Fund Management and Planning Authority; abbreviated CAMPA, to administer the fund of compensatory afforestation. Further, the Compensatory Afforestation Fund Rules of 2018 further streamlined the operations of the policy.
Initiated in China in 1999 in Shaanxi, Gansu, and Sichuan, the compensatory afforestation scheme has so far resulted to the appreciation of forest coverage by 23%. Between 2012 and 2016, around 33.8 million hectares of artificial forest was planted with most of it being a part of compensatory afforestation endeavours in the country. This is in conjunction with the ecological red line endeavour which restricts human activities in forests and calls for replacing the depleted ones. In the U.K, the Woodland Grant Scheme of 1988 later evolved to a compensatory afforestation scheme and accounts for 14.6% of the forests in the country. This is implemented by the FCA which is a government agency. In Australia, compensatory afforestation has been strict since before the adoption of the policy, there was massive destruction of forests which covered as much as 30% of natural forests. Ultimately, compensatory afforestation policies have evolved to better reforms over the years to become valuable contributors to the development of new forests and climate change. These are social enterprises which will benefit the community and even the continent in the long run.
Impacts
Positive Impact
Compensatory afforestation have contributed to the creation of 10% of the world's forests. It encourages and promotes the creation of new forests which helps in improving the climate of different locations since trees absorb carbon dioxide and help in completing the horologic cycle. In addition, it also helps in transforming of organic carbon in the soil and the associated soil properties which affects ecosystem function and plant diversity.
Negative Impact
The implementation of compensatory afforestation may result in the destruction of natural forests which may interfere with the ecosystem of the location. Because it advocates deforestation then the creation of entirely new forests. Notably, compensatory afforestation does not inhibit human activities on forests but rather creates room for them and calls for the planting of new ones. This has adverse impacts on the flora and fauna since natural forests present more benefits in terms of diversity compared to the artificial ones. Further, due to corruption, a report released in 2018 showed that CAMPA violates the Forest Conservation Act by allowing forests to be cleared and later grown by the same investors in the same location. This promotes wood-logging and destruction of natural habitats. For instance, in India compensatory afforestation has been blamed for presenting opportunities for the destruction of forests by established corporations yet the compensation is not equitable to the forests destroyed. Undoubtedly, the legitimization of forests destruction and encroaching of community owned lands can be attributed to compensatory afforestation. Destruction of a forest in a given location especially in towns results to more carbon dioxide in the atmosphere which affects air quality.
Implementation
Most of the funds that had been set aside for the purpose of compensatory afforestation has remained to be unused because of issues that have arisen between states over how the funds should be used. Because of the conflict, the funds have remained to be unused and frozen for even a longer period until a solution has been met. Also, the states have delayed collecting the funds hence contributing to the misappropriation of the funds that has been set aside for compensatory afforestation.
In India, there is need for strict implementation of the reform due to complaints by most individuals that CAMPA does not follow up to ensure that the destroyed forests are not wholly compensated. The High Court in India in the year 2000, ruled out on details that surrounded the good process of CA by the Ministry. Also, the High Court gave an order to the Ministry for leading the matter that delivers for description regarding errands in the period of the funding of the clearance of forests. In the year 2012, the high law court made a directory creating the Compensatory funds acknowledged by the supports is directed to CA. CA Fund Management and Planning Authority was therefore instructed by the Environment and forests ministry. In the year 2009, the High Court gave a mandatory that the CAMPA would be getting an advisory in the assembly under control of the Ministry.
Efficiency of the compensatory afforestation guidelines in India
The Act 1980 regarding the forest expects that afforestation is done while compensating the forest land that has been taken for uses of non-forest activities. In the year 2007, the environment ministry overseeing Forest and Climate Change. They gave out rules that specifically laid out the measures for identification together with the sustainability of land that has been set aside for the purpose of Afforestation compensation.
The guidelines from MoEF (Ministry of Environment, Forest) states that if the land that has been set aside and proposed as a place where forests can be relocated and contains some vegetation or density that is substantial, the arrangement will not be properly balanced because there is inadequate space for plant the required plants in the zone that has been suggested. Instead of declining the application, by the overseers and the project managers, the Environment and Forests Ministry gives a suggestion that one thousand plants can be planted per hectare in a land that does not have any forest. The Environment and Forest Ministry further state that the one thousand plants can be carried over to the next land if the plants cannot be able to fit in the one hectare that has been set aside.
References
Forests
Trees
Environmental policy | Compensatory Afforestation | [
"Biology"
] | 2,497 | [
"Forests",
"Ecosystems"
] |
60,916,154 | https://en.wikipedia.org/wiki/Skirret%20%28tool%29 | A skirret is an archaic form of chalk line. It is a wooden tool shaped like the letter "T", historically used to ensure the foundation of a building was straight by laying down string as a marker. Today it is obsolete and little known, save for its use in some Freemasonry ceremonies.
Shaped like the letter "T" — with two horizontal pieces of wood at the top and about halfway down the vertical stake. The horizontal two cross-pieces are connected by a dowel at each end, around which a long length of string is wound.
To use, the craftsman unwound the string from its spindle and utilised it to lay out the dimensions of the structure being built, acting on a centre pin from which a line was drawn out to mark the ground. In certain instances, with the spindle as the centre, the skirret could also have been used for drawing a circle.
References
Surveying instruments
Orientation (geometry)
Carpentry tools
Freemasonry | Skirret (tool) | [
"Physics",
"Mathematics"
] | 202 | [
"Topology",
"Space",
"Geometry",
"Spacetime",
"Orientation (geometry)"
] |
60,921,035 | https://en.wikipedia.org/wiki/International%20Giovanni%20Sacchi%20Landriani%20Prize | The International Giovanni Sacchi Landriani Prize is awarded every two years by the Istituto Lombardo, Accademia di Scienze e Lettere to recognize important original contributions to the field of numerical methods for partial differential equations during the preceding five years. The prize, first awarded in 1991, honors numerical analyst Giovanni Sacchi Landriani, who died in 1989 at age 31.
Recipients
The recipients of the International Giovanni Sacchi Landriani Prize are:
2007: Alessandro Veneziani
2005: Barbara Wohlmuth
2003: Claude Le Bris
1997: Benoît Perthame
1995: Anthony T. Patera
1993: Ricardo H. Nochetto
1991: Douglas N. Arnold
See also
List of mathematics awards
References
Mathematics awards
Awards established in 1991
1991 establishments in Italy
Italian awards | International Giovanni Sacchi Landriani Prize | [
"Technology"
] | 161 | [
"Science and technology awards",
"Mathematics awards"
] |
60,921,299 | https://en.wikipedia.org/wiki/Hasse%E2%80%93Schmidt%20derivation | In mathematics, a Hasse–Schmidt derivation is an extension of the notion of a derivation. The concept was introduced by .
Definition
For a (not necessarily commutative nor associative) ring B and a B-algebra A, a Hasse–Schmidt derivation is a map of B-algebras
taking values in the ring of formal power series with coefficients in A. This definition is found in several places, such as , which also contains the following example: for A being the ring of infinitely differentiable functions (defined on, say, Rn) and B=R, the map
is a Hasse–Schmidt derivation, as follows from applying the Leibniz rule iteratedly.
Equivalent characterizations
shows that a Hasse–Schmidt derivation is equivalent to an action of the bialgebra
of noncommutative symmetric functions in countably many variables Z1, Z2, ...: the part of D which picks the coefficient of , is the action of the indeterminate Zi.
Applications
Hasse–Schmidt derivations on the exterior algebra of some B-module M have been studied by . Basic properties of derivations in this context lead to a conceptual proof of the Cayley–Hamilton theorem. See also .
References
Abstract algebra | Hasse–Schmidt derivation | [
"Mathematics"
] | 258 | [
"Abstract algebra",
"Algebra"
] |
60,922,281 | https://en.wikipedia.org/wiki/Unidirectional%20data%20flow | In information technology and computer science, the pattern of applying one-way mutations on an immutable data state is called unidirectional data flow. Separation of state changes from presentation has many benefits and was popularized with Redux for unidirectional data flow combined with React for presenting, or rendering, data state.
See also
Data (computing)
Unidirectional network
Diode
References
External links
Redux concepts
MobX principles
Cognition
Models of computation | Unidirectional data flow | [
"Technology"
] | 96 | [
"Computing stubs",
"Computer science",
"Computer science stubs"
] |
60,922,339 | https://en.wikipedia.org/wiki/Gimlet%20%28eucalypt%29 | A gimlet is one of nine species of eucalypt in the genus Eucalyptus, series Contortae. These species are mainly characterised by having smooth, shiny, fluted trunks. The most widely distributed of the gimlets, is E. salubris which is found throughout the south-west of Western Australia, other than in coastal areas and wet forests. The other eight species have a narrower distribution in the Goldfields-Esperance region. The only gimlet that is a mallee is E. effusa which forms a lignotuber from which it can resprout after fire. The other eight gimlets are mallets, do not form a lignotuber, are killed by fire and regenerate from seed. These species are E. campaspe, E. creta, E. diptera, E. jimberlanica, E. ravida, E. terebra, E. salubris and E. tortilis.
References
Eucalyptus
Plant common names | Gimlet (eucalypt) | [
"Biology"
] | 213 | [
"Plant common names",
"Common names of organisms",
"Plants"
] |
60,923,409 | https://en.wikipedia.org/wiki/Isoarborinol | Isoarborinol is a triterpenoid ubiquitously produced by angiosperms and is thus considered a biomarker for higher plants. Though no isoarborinol-producing microbe has been identified, isoarborinol is also considered a possible biomarker for marine bacteria, as its diagenetic end product, arborane, has been found in ancient marine sediments that predate the rise of plants. Importantly, isoarborinol may represent the phylogenetic link between hopanols and sterols.
Chemistry
Isoarborinol is a pentacyclic triterpenoid, a class of 30-carbon isoprenoid compounds commonly found in higher plants. It is primarily a hydrocarbon molecule composed of four cyclohexane rings, one cyclopentane ring, six methyl groups, one alcohol group and one isopropyl group. It is structurally similar to plant cyclics in the lupenoid series (including lupeol, betulin and lupane), primarily differing in the position of the isobutyl functional group (located on C21 of the cyclopental ring for isoarborinol, and on C19 for the lupenoids). Isoarborinol likely serves as a fluidity-buffering component of biological membranes, similar to sterols and hopanols.
Distribution
The known distribution of isoarborinol in extant organisms is predominantly limited to a few angiosperms (e.g., the family Gramineae), which led many to view isoarborinol as a biomarker for higher plants. In the 1990s, a series of papers published by Verena Hauke and colleagues presented compelling evidence for the existence of isoarborinol during the Permian and Triassic periods based on detection of arborane (the diagenetic product of isoarborinol) in ancient sediments. These geological periods significantly predate the late-Jurassic first appearance of angiosperms, precluding the possibility that isoarborinol was produced by higher plants. Furthermore, the arborane compounds detected had carbon isotopic signatures inconsistent with plant origin, and arborane was additionally isolated from lacustrine sediments that lacked angiosperms. Taken together, these observations support a microbial origin for isoarborinol, though no isoarborinol-producing microbe has yet been found. However, the marine heterotrophic bacterium Eudoraea adriatica was discovered to make adriaticol and eudoraenol, two isomers of isoarborinol, suggesting that an extant isoarborinol producer may exist.
Evolutionary significance
The enzyme responsible for making isoarborinol may represent the evolutionary link between the hopanol-producing enzymes in bacteria and the sterol-producing enzymes in eukaryotes. These enzymes are part of the class of terpene cyclases, which cyclize either squalene or oxidosqualene into four- or five-membered ring compounds through pathways that proceed through different structural conformations (all-chair or chair-boat-chair). Each terpene cyclase uses a different combination of these aspects to produce the final polycyclic triterpenoid compound, leading to great variety in the pathways of polycyclic triterpenoid production.
Squalene-hopene cyclase (SHC) synthesizes hopanols and is generally assumed to have evolved before the sterol-producing enzyme oxidosqualene cyclase (OSC). Whereas SHC folds squalene into a five-membered ring via an all-chair conformation intermediate, OSC folds oxidosqualene into a four-membered ring via a chair-boat-chair conformation. Isoarborinol cyclase uses a combination of these aspects, cyclizing oxidosqualene into a five-membered ring via a chair-boat-chair conformation. Given the apparent intermediate nature of its pathway (between those used by SHC and OSC), isoarborinol cyclase has been proposed to represent the enzymatic intermediate of the evolutionary transition from SHC to OSC. However, phylogenetic analyses of the evolutionary relationships between terpene cyclases suggest that SHC and OSC diverged from a common ancestor, which renders the evolutionary significance of isoarborinol cyclase unclear. Though no extant microbe is known to produce isoarborinol, the discovery of eudoraenol synthase (which produces isoarborinol-like lipids through a similar pathway used by isoarborinol cyclase) in E. adriatica opens the door for future investigations into the mechanisms of polycyclic triterpenoid biomarker synthesis and the phylogenetic relationships between the enzymes involved.
Measurement
In extant organisms, isoarborinol can be found in its intact form with its polar hydroxyl group. In sediments, isoarborinol is diagenetically converted to its fully saturated form, arborane. Thus, techniques designed to extract and analyze isoarborinol must consider the chemistry of the molecule being interrogated. Common approaches to analyzing biomarker compounds include identifying their structures, quantifying their abundances and measuring the isotopic compositions of their various elements (carbon, nitrogen, sulfur, etc.).
Extraction and purification
Isoarborinol can be extracted from biological material via Bligh and Dyer, while arborane can be extracted from sedimentary rocks via solvent extraction. Column chromatography (often high-performance liquid chromatography (HPLC)) is used to partition the lipids into different phases (e.g., saturates, aromatics and polars) based on their polarities. Isoarborinol will elute with the polar fraction and its alcohol group must often be derivatized (e.g., with TMS, TFA or methanol) before it can be analyzed. Arborane will elute with the aromatic fraction and does not need to be derivatized before analysis.
Analysis
Isoarborinol and arborane can be analyzed via gas chromatography-mass spectrometry (GC/MS), during which compounds elute based on their partitioning properties between the mobile and stationary phases of the GC column, then are subsequently fragmented and ionized, and the resulting charged fragments are separated based on their mass-to-charge ratios (m/z). Together, information about the relative retention times and mass spectra patterns of molecules are used to identify compounds of interest. For isoarborinol derivatized with TMS, a characteristic mass fragment peak is found at m/z = 241. Alternatively, isoarborinol and/or arborane can also be analyzed via liquid chromatography-mass spectrometry (LC/MS) or characterized by nuclear magnetic resonance (NMR). The carbon and hydrogen isotopic ratios in isoarborinol/arborane can be measured via gas chromatography coupled to isotope ratio mass spectrometry.
References
Angiosperms
Triterpenes
Secondary alcohols | Isoarborinol | [
"Biology"
] | 1,508 | [
"Plants",
"Angiosperms"
] |
60,923,680 | https://en.wikipedia.org/wiki/Sukbok%20Chang | Sukbok Chang (; born August 1, 1962) is a South Korean organic chemist. He is a distinguished professor in the Department of Chemistry at Korea Advanced Institute of Science and Technology (KAIST). He is also the director of the Institute for Basic Science (IBS) Center for Catalytic Hydrocarbon Functionalizations (CCHF). He was an associate editor on ACS Catalysis and has served on the editorial advisory boards of The Journal of Organic Chemistry, Journal of the American Chemical Society, and Accounts of Chemical Research. His major research interest is transition metal catalyzed C-H bond functionalization for the carbon-carbon bond and carbon-heteroatom bond formation.
Career
Sukbok Chang received his B.S degree from Korea University in 1985, and M.S degree from KAIST in 1987. Then, he joined Eric N. Jacobsen's group and received his PhD in 1996 at Harvard University. He subsequently worked with Robert H. Grubbs at Caltech as a postdoctoral fellow from 1996 to 1998. In early 1998, he joined the faculty of Ewha Womans University as an assistant professor, and moved to KAIST as a full professor in 2002. In 2012, he was selected as a director of the Center for Catalytic Hydrocarbon Functionalizations at the Institute for Basic Science, which is the biggest Korean government funded research institute. He also has been working as an associate editor of the journal ACS Catalysis since 2015. In 2023, he was selected to co-run the KAIST Cross Generation Creation Lab, a laboratory designed to continue the know-how of professors about to retire through collaboration with younger professors.
Major contributions
Chang's group studies new organic reactions and mechanisms with transition metal catalysis. In particular, his group contributed to the development of "copper catalyzed multicomponent coupling" in the 2000s. Since 2008, his group has focused on C-H functionalization and made a number of contributions.
Copper-catalyzed multicomponent coupling
Cu-catalyzed multicomponent coupling is a notable process developed by Chang's group. In 2005, they published a highly efficient and mild catalytic three component coupling between an alkyne, sulfonyl azide, and amine. Unlike click chemistry which generates 1,4-triazoles as products, in this case a Cu(I) catalyst, sulfonyl azide and alkyne generate ketenimine intermediate after releasing N2 gas. This electrophilic ketenimine intermediate reacts with amines and to generate asymmetric imines as products. Chang's group also showed water, alcohols, the C3 position of pyrrole and other nucleophiles can be used in this reaction.
Rhodium, Iridium-catalyzed C-N bond formation
Rhodium or iridium catalyzed C-H amidation and amination are other achievements of his group. In 2012, his group published rhodium catalyzed intermolecular amidation of arenes using sulfonyl azide as a nitrene precursor. This reaction generates N2 as the single byproduct, doesn't need external oxidant, has broad substrate scope and high functional group tolerance. Chang's group advanced their work by using different directing groups, different azides and various substrates. They also published that iridium also works well for C-H amidation/amination.
In 2016, Chang's group discovered new nitrogen sources. Their new nitrene precursor, 1,4,2-dioxazol-5-one, is more convenient to prepare, store and use compared to azides. Moreover, it has a strong affinity to the rhodium or Iridium metal center, and thus gives excellent amidation efficiency. They later published selective formation of gamma-lactams via C-H amidation with this type of nucleophile.
Honors and awards
2023: The Asian Scientist 100, Asian Scientist
2022: Ho-Am Prize in Science
2019: Top Scientist and Technologist Award of Korea, Korean Federation of Science and Technology Societies ()
2018: Korea Toray Science Award, Korea Toray Science Foundation
2018: JSPS Invitational Fellowship, Japan Society for the Promotion of Science
2018: Grand Academic Research Award, KAIST
2017: 1st ACS-KCS Excellence Award, American Chemical Society and Korean Chemical Society
2017: Humboldt Research Award, Alexander von Humboldt Foundation
2016: Yoshida Prize, International Organic Chemistry Foundation
2015-2020: Highly Cited Researcher in chemistry, Clarivate Analytics
2015: Knowledge Creation Award, Ministry of Science, ICT and Future Planning
2014: Member of the Korean Academy of Science and Technology
2013: Korea Science Award
2013: Kyung-Ahm Prize, Kyung-Ahm Education & Cultural Foundation
2010: KCS Academic Award, Korean Chemical Society
2008: Star Faculty, Korea Research Foundation
2006: One of 50 Representative Research Performances, Korea Science & Engineering Foundation
2005: Shim Sang Cheol Award, Korean Chemical Society
2003: Thieme Journals Award, Synlett/Synthesis Professorship Award in Asian Area
2002: Young Chemist Award, Korean Chemical Society sponsored by WILEY
References
1962 births
Living people
Academic staff of Ewha Womans University
Harvard University alumni
KAIST alumni
Academic staff of KAIST
Korea University alumni
Institute for Basic Science
South Korean organic chemists
Recipients of the Ho-Am Prize in Science | Sukbok Chang | [
"Chemistry"
] | 1,118 | [
"South Korean organic chemists",
"Organic chemists"
] |
60,924,277 | https://en.wikipedia.org/wiki/NGC%204800 | NGC 4800 is an isolated spiral galaxy in the constellation Canes Venatici, located at a distance of from the Milky Way. It was discovered by William Herschel on April 1, 1788. The morphological classification of this galaxy is SA(rs)b, indicating a spiral galaxy with no visual bar at the nucleus (SA), an incomplete ring structure (rs), and moderately-tightly wound spiral arms (b). The galactic plane is inclined to the line of sight by an angle of 43°, and the long axis is oriented along a position angle of 25°. There is a weak bar structure at the nucleus that is visible in the infrared.
The galaxy has a low-luminosity active galactic nucleus with an HII region at the core. The circumnuclear zone contains a double ring structure of "ultra-compact nuclear rings"; the inner ring has a radius of 30 pc and the outer ring's radius is about 130 pc. The upper limit on the mass of the central supermassive black hole is estimated as , or 20 million times the mass of the Sun.
References
External links
Unbarred spiral galaxies
Canes Venatici
4800
043931 | NGC 4800 | [
"Astronomy"
] | 246 | [
"Canes Venatici",
"Constellations"
] |
59,489,005 | https://en.wikipedia.org/wiki/Trollius%20%C3%97%20cultorum | Trollius × cultorum is a group of hybrid flowering plants of garden origin, belonging to the buttercup family Ranunculaceae. There are several cultivars, derived from T. europaeus, T. asiaticus and T. chinensis. These are clump-forming herbaceous perennials whose preferred location is heavy, moist or even boggy ground, in full sun or partial shade. Typically growing to tall, they bear showy double flowers up to in diameter. Flowers appear in shades of cream, yellow and orange. The curved "petals" are actually sepals, surrounding the smaller, nectar-bearing petals. The spherical or cupped shape of the blooms gives rise to the common name globeflower, which they share with other Trollius species.
The Latin specific epithet cultorum means "relating to gardens, cultivation".
Trollius × cultorum is an unresolved name, meaning that it has not yet been accepted as a correct botanical name or synonym.
However, plants are widely offered in the horticultural trade. The cultivars 'Superbus' and 'Orange Princess' have gained the Royal Horticultural Society's Award of Garden Merit. Other cultivars include 'Alabaster', 'Lemon Queen' and 'New Moon'.
References
cultorum
Hybrid plants | Trollius × cultorum | [
"Biology"
] | 261 | [
"Hybrid plants",
"Plants",
"Hybrid organisms"
] |
59,489,091 | https://en.wikipedia.org/wiki/NGC%202527 | NGC 2527 (also catalogued as NGC 2520) is an open cluster in the constellation Puppis. It was discovered by William Herschel on December 9, 1784. The cluster was also observed by John Herschel on January 7, 1831. He also observed it on February 5, 1837, identifying it as a different object, which was catalogued as NGC 2520. It is a poor cluster and with no central concentration, with Trumpler class III1p.
The core radius of the cluster is 1 parsec (3.3 light years), while the tidal radius is 5.1 parsecs (17 light years) and represents the average outer limit of NGC 2527, beyond which a star is unlikely to remain gravitationally bound to the cluster core.
37 stars, probable members of the cluster, are located within the central part of the cluster and 96 probable members are located within the angular radius of the cluster. The brightest star members are A-type stars, with the brightest being an A3 star with magnitude 9.38. In the cluster has been detected one white dwarf, with mass . Its age is estimated to be years and the progenitor star has initial mass circa 3.1 . The turn-off mass of the cluster is at 2.8 . The metallicity of the cluster is -0.01, similar to the solar one.
NGC 2527 lies 3.8 degrees south of Rho Puppis and can be seen with 50mm binoculars as a moderately large, bright patch of haze, with no stars visible with direct vision.
References
External links
Open clusters
2527
Puppis
Discoveries by William Herschel | NGC 2527 | [
"Astronomy"
] | 335 | [
"Puppis",
"Constellations"
] |
59,490,639 | https://en.wikipedia.org/wiki/NGC%207160 | NGC 7160 is an open cluster in the constellation Cepheus. It was discovered by William Herschel on November 9, 1789. The cluster was also observed by John Herschel on October 7, 1829. It is a poor cluster and with little central concentration, with Trumpler class II3p. It is part of the stellar association Cepheus OB2, located one degree south-southwest of VV Cephei.
Description
NGC 7160 is a young cluster, whose age is estimated to be between 10 and 19 million years. The cluster presents no extended infrared emission when observed by Spitzer Space Telescope and Herschel Space Telescope which suggests that the molecular cloud in which it was formed has been removed. NGC 7160 lies within the Cepheus Bubble, an expanding dusty shell with a diameter of about 10 degrees, which corresponds to 120 pc (390 ly) at the distance of NGC 7160. It is bordered by HII regions like IC 1396, in which is located the open cluster Trumpler 37. The total mass of molecular gas in the Cepheus Bubble is estimated to be 105 based on CO emission mapping. The bubble is believed to have been formed by the stellar wind and photoionisation from OB stars that have exploded as supernovae. Mu Cephei, Nu Cephei, and NGC 7160 may have been companions of those stars. It has been suggested that Lambda Cephei and 68 Cygni are runaway stars from that area.
The core radius of the cluster is 0.73 parsec (2.4 light years), while the tidal radius is 5.7 parsecs (18.5 light years) and represents the average outer limit of NGC 7160, beyond which a star is unlikely to remain gravitationally bound to the cluster core.
16 stars, probable members of the cluster, are located within the central part of the cluster, and 71 probable members are located within the angular radius of the cluster. Among the members is EM Cephei (mag 7.03), a variable star whose spectrum switches between B and Be star states. It is suggested it is a Be star with a variable circumstellar disk with mass losses per year. One low mass member, with spectral type K4.5 is accreting, suggesting the presence of a protoplanetary disk. It is characterised by very low far-IR flux with a high accretion rate.
See also
List of open clusters
References
External links
7160
Cepheus (constellation)
Open clusters
Discoveries by William Herschel | NGC 7160 | [
"Astronomy"
] | 515 | [
"Constellations",
"Cepheus (constellation)"
] |
59,492,054 | https://en.wikipedia.org/wiki/Sala%20Senkayi | Sala Nanyanzi Senkayi is an African environmental scientist at the United States Environmental Protection Agency. She was the first Ugandan-born woman to win the Presidential Early Career Award for Scientists and Engineers.
Early life and education
Senkayi is the daughter of Abu Senkayi and Sunajeh Senkayi. Her family are from Butambala District in Uganda. Her father was an environmental scientist and worked at Texas A&M University as a research scientist from 1977.
Senkayi obtained a bachelor's degree in biomedical sciences from Texas A&M University in College Station, Texas. She joined the University of Texas at Arlington, earning two more Bachelor's degrees in microbiology and biology. Later, she earned a master's degree (2010) and a PhD (2012) degrees in environmental and earth sciences from the same university. Her PhD thesis considered the association between childhood leukaemia and proximity to airports in Texas. She found that benzene emissions were a predictor for childhood leukaemia. During her graduate studies Muwenda Mutebi II of Buganda and Sylvia Nnaginda visited her in Texas.
Career
Senkayi joined the United States Environmental Protection Agency in 2007. She works with local children in schools and colleges talking about the environment. She initiated the EPA Converses with Students webcast, an opportunity for children to speak to scientists who worked on environmental protection on Earth Day. Her research focuses on water quality protection and she is the Water Quality Division Quality Assurance Officer. In 2017 Senkayi was awarded the Presidential Early Career Award for Scientists and Engineers for her "transformative" community outreach and research.
References
Texas A&M University alumni
University of Texas at Arlington alumni
Environmental scientists
21st-century Ugandan women scientists
21st-century Ugandan scientists
Year of birth missing (living people)
Living people
Recipients of the Presidential Early Career Award for Scientists and Engineers | Sala Senkayi | [
"Environmental_science"
] | 382 | [
"Environmental scientists"
] |
59,493,125 | https://en.wikipedia.org/wiki/Gloria%20Dubner | Gloria Dubner (born May 5, 1950) is an Argentinian astrophysicist and Director of the Instituto de Astronomía y Física del Espacio in Buenos Aires and a Senior Researcher at the National Scientific and Technical Research Council. She is known for her research on supernovas.
Education
Dubner was born on May 5, 1950, in the city of Chajarí, located in the Entre Ríos Province in Argentina. She received her Licentiate degree in physics in 1974 from the University of Buenos Aires at the age of 23. She then attended National University of La Plata, where she received her PhD in physics in 1982 under the mentorship of astronomer and Guggenheim Fellow Fernando Raúl Colomb.
Research and career
Career trajectory
Between 1975 and 1987, Dubner worked at the Argentine Institute of Radio Astronomy. In 1988, she began working at the Instituto de Astronomía y Física del Espacio (IAFE). In 1997, she also was appointed as a researcher at the National Scientific and Technical Research Council, continuing her study of supernovas. In 2009, she became the Director of IAFE and also serves as the Director of the Supernovas and Interstellar Environment group.
Research contributions
Dubner has participated in a number of international collaborations to study galactic supernova remnants. For instance, in 1994, she and her American collaborators Frank Winkler and W. Miller Gross were awarded a National Science Foundation grant to image the expanding shell of gas left over after a star explodes using data collected from radio telescopes in the US and Argentina.
Starting in 2015, Dubner also led a collaboration between five observatories that led to the production of the most detailed image produced of the Crab Nebula, a bright supernova explosion first observed by Chinese astronomers in 1054. The collaboration leveraged data collected at different wavelengths to create a composite image using: infrared data generated by the Spitzer Space Telescope from NASA's Jet Propulsion Laboratory, visible light data from the Hubble Space Telescope, ultraviolet data from the XMM-Newton operated by the European Space Agency, radio image and X-ray data from NASA's Chandra X-ray Observatory, and radio data from the Very Large Array operated by the National Radio Astronomy Observatory.
Leadership and recognition
Dubner is an active member of the International Astronomical Union (IAU), serving on a variety of commissions including the Working Group for Historic Radio Astronomy, the Division for Interstellar Matter and Local Universe, and the Commission for Astrochemistry. In 2006, she served on the Organizing Committee to report advances in the field of radio astronomy between 2002 and 2005. In 2012, she was part of the organizing committee of the IAU's XXVIII General Assembly for Women in Astronomy Meeting. In June 2008, the minor planet 9515 Dubner was named in her honor, recognizing her achievements at the IAU. The planet was first discovered at the observatory in El Leoncito National Park in 1975. In 2023 she won the Platinum Konex Award as the most important physicist in Argentina.
References
Argentine women physicists
1950 births
Women astronomers
20th-century Argentine astronomers
University of Buenos Aires alumni
National University of La Plata alumni
Living people
21st-century Argentine astronomers | Gloria Dubner | [
"Astronomy"
] | 650 | [
"Women astronomers",
"Astronomers"
] |
59,493,360 | https://en.wikipedia.org/wiki/NGC%206910 | NGC 6910 is an open cluster in the constellation Cygnus. It was discovered by William Herschel on October 17, 1786. The cluster was also observed by John Herschel on September 18, 1828. It is a poor cluster with prominent central concentration and Trumpler class I2p.
NGC 6910 is the core cluster of the stellar association Cygnus OB9.
Details
NGC 6910 is located half a degree east-north east of Gamma Cygni, also known as Sadr. It may be physically related with the nebula IC 1318 (also known as the Gamma Cygni Nebula) as it lies at a similar distance, behind the galactic Great Rift. Cygnus OB9 is located within the Orion Arm of the Milky Way. Cygnus OB9's dimensions in the sky are 2.5 degrees by 1.5 degrees, which corresponds at its distance to 175×105 light years across. It includes many OB stars, along with supergiant stars, like the red supergiant RW Cygni. Gamma Cygni is a foreground star, lying at a distance of approximately 1,500 light years. Because it lies behind a number of molecular clouds, the light from NGC 6910 is dimmed by more than one magnitude.
The core radius of the cluster is 0.8 parsec (2.6 light years), while the tidal radius is 4.2 parsecs (13.7 light years) and represents the average outer limit of NGC 6910, beyond which a star is unlikely to remain gravitationally bound to the cluster core.
125 stars, probable members of the cluster, are located within the central part of the cluster, and 280 probable members are located within the angular radius of the cluster. The brightest apparent member of NGC 6910 is a blue supergiant HD 194279 (V2118 Cygni) with spectral type B2 and apparent magnitude 7.0. It is located at the southeast edge of the cluster. It is a variable star with P Cygni profile. A mag 8.1 star lies at the northwest edge of the cluster and a mag 8.5 O6 giant star (HD 229196, also known as V2245 Cygni) lies a bit southwest from the line connecting the two brightest stars. Other members of the cluster include two 10.3 mag stars, one being an O9.5 and the other a B0.5 main sequence stars. The star NGC 6910 37 is categorised based on its emission as a Be star and NGC 6910 14 and NGC 6910 25 are beta Cephei variables. In total there are four beta Cephei variables in the cluster, a rather high number. Their presence has been attributed to the higher metallicity of the cluster.
Observing NGC 6910
Although visible via binoculars, the cluster is too compact to resolve in low power instruments. Individual stars can be seen with 15×100 binoculars. When seen in low magnification through a 5-inch telescope, the cluster looks like a crescent between the two brighter stars, while more powerful magnification reveals more stars forming streams extending to either side of the cluster.
References
External links
6910
Cygnus (constellation)
Open clusters
Orion–Cygnus Arm
Discoveries by William Herschel | NGC 6910 | [
"Astronomy"
] | 671 | [
"Cygnus (constellation)",
"Constellations"
] |
59,493,423 | https://en.wikipedia.org/wiki/Alice%20Archenhold | Alice Archenhold (née Markus; 27 August 1874 – 9 February 1943) was a German astronomer whose husband was fellow astronomer Friedrich Simon Archenhold.
Alice Markus was born in Wiesbaden, Germany, and married Friedrich Simon Archenhold in July 1897 and lived in Berlin. They went on to have five children together.
Her sons, Günter, who became an astronomer, and Horst, both fled to England, but Alice was arrested and deported (along with her daughter Hilde) to Theresienstadt concentration camp, in Czechoslovakia, where she died on 9 February 1943.
She is commemorated on her husband's grave at the Zentralfriedhof Friedrichsfelde, Berlin.
In 2010 a street in Treptow-Köpenick was renamed after her as Alice Archenhold Weg.
See also
Photographs of Archenhold family: https://theskywasthelimit.de/en/history/
References
1874 births
Place of birth missing
1943 deaths
20th-century German astronomers
Women astronomers
German people who died in the Theresienstadt Ghetto
Women in Nazi Germany
Jewish German scientists
Jewish women scientists
Jewish astronomers | Alice Archenhold | [
"Astronomy"
] | 232 | [
"Astronomers",
"Jewish astronomers"
] |
59,493,771 | https://en.wikipedia.org/wiki/NGC%20709 | NGC 709 is a lenticular galaxy located 150 million light-years away in the constellation Andromeda. It was discovered by the Irish engineer and astronomer Bindon Blood Stoney on October 28, 1850 and is a member of the galaxy cluster Abell 262.
See also
List of NGC objects (1–1000)
References
External links
709
6969
Andromeda (constellation)
Astronomical objects discovered in 1850
Lenticular galaxies
Abell 262
Discoveries by Bindon Blood Stoney | NGC 709 | [
"Astronomy"
] | 98 | [
"Andromeda (constellation)",
"Constellations"
] |
59,494,314 | https://en.wikipedia.org/wiki/Michael%20Bulmer | Michael George Bulmer FRS (born 10 May 1931) is a British biostatistician. He is an emeritus fellow of Wolfson College, Oxford, and a Fellow of the Royal Society of London. He is known for his work in quantitative genetics and on the biology of twinning, as well as for his 2003 biography of Francis Galton.
Biography
Bulmer was born in Birmingham, England, in 1931. After graduating from Rugby School, he studied at Merton College, Oxford, from 1949 to 1957, taking a B.A. in animal physiology in 1952, a diploma in applied statistics the following year, a D.Phil. in statistics in 1957, and a D.Sc. He then lectured at the University of Manchester from 1957 to 1959, after which he became a lecturer in biomathematics at the University of Oxford. In 1991, he left Oxford to become a professor in the Department of Biological Sciences at Rutgers University, where he remained until 1995.
References
External links
Faculty page
1931 births
Living people
English statisticians
20th-century British biologists
Biostatisticians
Fellows of Wolfson College, Oxford
Academics of the University of Oxford
Academics of the University of Manchester
Rutgers University faculty
Alumni of the University of Oxford
People educated at Rugby School
People from Birmingham, West Midlands
Theoretical biologists
English biologists
Fellows of the Royal Society
Alumni of Merton College, Oxford | Michael Bulmer | [
"Biology"
] | 278 | [
"Bioinformatics",
"Theoretical biologists"
] |
59,494,678 | https://en.wikipedia.org/wiki/NGC%20710 | NGC 710 is a spiral galaxy located 260 million light-years away in the constellation Andromeda. It was discovered by the Irish engineer and astronomer Bindon Blood Stoney on October 28, 1850 and is a member of the galaxy cluster Abell 262.
It is also a radio galaxy.
SN 2002eo
On August 20, 2002 a type II supernova designated as SN 2002eo was discovered in NGC 710.
See also
List of NGC objects (1–1000)
References
External links
710
6972
Andromeda (constellation)
Astronomical objects discovered in 1850
Spiral galaxies
Abell 262
1349
Radio galaxies
Discoveries by Bindon Blood Stoney | NGC 710 | [
"Astronomy"
] | 131 | [
"Andromeda (constellation)",
"Constellations"
] |
59,495,493 | https://en.wikipedia.org/wiki/NGC%206621 | NGC 6621 is an interacting spiral galaxy in the constellation Draco. It lies at a distance of about 260 million light-years. NGC 6621 interacts with NGC 6622, with their closest approach having taken place about 100 million years ago. The pair was discovered by Edward D. Swift and Lewis A. Swift on June 2, 1885. Originally NGC 6621 was assigned to the southeast galaxy, but now it refers to the northern one. NGC 6621 and NGC 6622 are included in the Atlas of Peculiar Galaxies as Arp 81 in the category "spiral galaxies with large high surface brightness companions".
NGC 6621 is the larger of the two, and is a very disturbed spiral galaxy. The encounter has pulled a long tail out of NGC 6621 that has now wrapped at the north behind its body. The collision has also triggered extensive star formation between the two galaxies. The most intense star formation takes place in the region between the two nuclei, where a large population of luminous clusters, also known as super star clusters, has been observed. At this region is observed the most tidal stress. Many large clusters are also observed in the tail and the nucleus of NGC 6621. The brightest and bluest clusters are less than 100 million years old, with the youngest being less than 10 million years old. The side of the galaxy further from the companion features noticeably less star formation activity.
NGC 6621 is characterised as a luminous infrared galaxy, with its infrared luminosity being 1011.24 . NGC 6621 contributes nearly all of the radio and far infrared flux of the pair. When observed in H-alpha, the centre of the galaxy has two bright sources separated by 3 arcseconds, with the southwest being brighter while the northeastern one coincides with the nucleus of NGC 6621.
Two supernovae have been detected in NGC 6621. The first, SN2010hi (type unknown, mag. 18), was discovered on 1 September 2010, lying 30" east and 4" north of the center of the galaxy. The second, SN2019hsx (typeIc-BL, mag. 18.6), was discovered on 2 June 2019.
See also
List of NGC objects (6001–7000)
References
External links
Spiral galaxies
Peculiar galaxies
Luminous infrared galaxies
Draco (constellation)
6621
11175
081
61582
Interacting galaxies | NGC 6621 | [
"Astronomy"
] | 484 | [
"Constellations",
"Draco (constellation)"
] |
59,496,435 | https://en.wikipedia.org/wiki/Hazel%20Assender | Hazel Elaine Assender , is the head of Department and Professor of Materials at the Department of Materials, University of Oxford. She is an expert in polymer chemistry, thin film electronics and nanomaterials. Assender is a fellow of Linacre College, Oxford.
Education
Assender studied the Natural Sciences Tripos at the University of Cambridge, graduating in 1990. In 1990, Assender started her PhD in the Department of Materials Science and Metallurgy and completed her thesis on "Magnetically induced microstructures in liquid crystalline polymers" in 1994.
Research and career
After two years as a post doctoral researcher, in 1996 Assender moved to a lectureship in the Department of Materials at the University of Oxford where she focuses on thin films and coatings of polymer materials and onto polymer substrates. During her time in Oxford, she has developed expertise in roll-to-roll deposition, gas barriers, photovoltaics, and polymer electronics (including transistors and circuits). Assender has worked 80% full-time since her second child was born.
In 2001 Assender co-edited the book "Aerospace Materials" with Brian Cantor and Patrick Grant. She spoke at the 2015 University of Cambridge "Worshipful Company of Armourers and Brasiers Company forum", a highlight of the academic UK materials science calendar, to highlight roll-to-roll vacuum processing to create multi-layer polymer electronic thin films.
Assender continues to collaborate across the UK and is currently a member of the Centre for Plastic Electronics Centre for Doctoral Training (with colleagues from Oxford, Imperial, and Queen Mary University London). Assender's research is inspired by her desire to solve industrial challenges. Her recent work has considered wearable electronics as part of the Wearable and Flexible Technologies (WAFT) consortium with colleagues at Oxford, Southampton and Exeter Universities.
References
Living people
Year of birth missing (living people)
Academics of the University of Oxford
Alumni of the University of Cambridge
Women materials scientists and engineers
British women physicists
British metallurgists
Fellows of Linacre College, Oxford | Hazel Assender | [
"Materials_science",
"Technology"
] | 426 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
59,497,390 | https://en.wikipedia.org/wiki/NGC%207674 | NGC 7674 is a spiral galaxy located in the constellation Pegasus. It is located at a distance of about 350 million light years from Earth, which, given its apparent dimensions, means that NGC 7674 is about 125,000 light years across. It was discovered by John Herschel on August 16, 1830.
Characteristics
The galaxy is seen nearly face-on, at an inclination of 31 degrees. The central bar-shaped structure, measuring 15×5 arcseconds is made up of stars. The galaxy has two spiral arms that become broader as the distance increases. One arm vanishes at the point it overlaps with the nearby galaxy NGC 7674A. The shape of NGC 7674, including the long narrow streamers emanating northeast and northwest of the galaxy can be accounted for by tidal interactions with its companions. There is no dwarf galaxy seen inside the streamers. It is featured in Arp's Atlas of Peculiar Galaxies as number 182, in the category "galaxies with narrow filaments".
NGC 7674 has a powerful active nucleus of the kind known as a type 2 Seyfert that is perhaps fed by gas drawn into the center through the interactions with the companions. In 1975, observations of excess ultraviolet emission led to designation as Markarian 533 in Markarian's catalog. Later, using spectropolarimetry, emission characteristic of a hidden broad-line region (BLR), visible only in the polarized flux spectrum was detected, implying that the nucleus of NGC 7674 is an obscured type 1 Seyfert, hidden by a dust torus. In the center of NGC 7674 lies a supermassive black hole whose mass is estimated to be nearly based on stellar velocity dispersion. When observed in radio waves, NGC 7674 features two radio jets with an S-shape, 0.7 kpc long. The reason for this shape may be a change in the black hole spin axis due to a minor merger, the presence of a binary black hole or due to interactions with the interstellar medium. Two radio sources with characteristics similar to accreting supermassive black holes have been observed in the centre of NGC 7674, at a projected separation of 0.35 parsec.
NGC 7674 falls into the family of luminous infrared galaxies, with its infrared luminosity being 1011.54 . The luminous infrared galaxies are characterised by intense star forming activity. The total star formation rate in NGC 7674 is estimated to be 54 per year, and the star formation rate at the nucleus is 4.3 per year.
Two supernovae have been observed in NGC 7674, SN 2011ee (type Ic, mag 18.6) and SN 2011hb (type Ia, mag 18.8).
Nearby galaxies
NGC 7674 is the brightest and largest member of the isolated Hickson 96 compact group of galaxies, consisting of four galaxies. NGC 7674 forms a pair with its smaller companion NGC 7674A, which lies 34 arcseconds to the north. NGC 7675, an elliptical galaxy, lies 2.2 arcminutes to the east.
References
External links
NGC 7674 on SIMBAD
Unbarred spiral galaxies
Peculiar galaxies
Seyfert galaxies
Luminous infrared galaxies
Pegasus (constellation)
7674
12608
182
71504
Markarian 0533
Discoveries by John Herschel
Astronomical objects discovered in 1830 | NGC 7674 | [
"Astronomy"
] | 707 | [
"Pegasus (constellation)",
"Constellations"
] |
59,497,796 | https://en.wikipedia.org/wiki/Zero%20point%20%28photometry%29 | In astronomy, the zero point in a photometric system is defined as the magnitude of an object that produces 1 count per second on the detector. The zero point is used to calibrate a system to the standard magnitude system, as the flux detected from stars will vary from detector to detector. Traditionally, Vega is used as the calibration star for the zero point magnitude in specific pass bands (U, B, and V), although often, an average of multiple stars is used for higher accuracy. It is not often practical to find Vega in the sky to calibrate the detector, so for general purposes, any star may be used in the sky that has a known apparent magnitude.
General formula
The equation for the magnitude of an object in a given band is
where is the magnitude of an object, is the flux at a specific wavelength, and is the sensitivity function of a given instrument. Under ideal conditions, the sensitivity is 1 inside a pass band and 0 outside a pass band. The constant is determined from the zero point magnitude using the above equation, by setting the magnitude equal to 0.
Vega as calibration
Under most circumstances, Vega is used as the zero point, but in reality, an elaborate "bootstrap" system is used to calibrate a detector. The calibration typically takes place through extensive observational photometry as well as the use of theoretical atmospheric models.
Bolometric magnitude zero point
While the zero point is defined to be that of Vega for passband filters, there is no defined zero point for bolometric magnitude, and traditionally, the calibrating star has been the sun. However, the IAU has recently defined the absolute bolometric magnitude and apparent bolometric magnitude zero points to be 3.0128×1028 W and 2.51802×10−8 W/m2, respectively.
See also
Luminosity
Bolometric correction
Absolute magnitude
References
Photometric systems
Observational astronomy | Zero point (photometry) | [
"Astronomy"
] | 403 | [
"Observational astronomy",
"Astronomical sub-disciplines"
] |
59,499,174 | https://en.wikipedia.org/wiki/Herrmann%27s%20catalyst | Herrmann's catalyst is an organopalladium compound that is a popular catalyst for the Heck reaction. It is a yellow air-stable solid that is soluble in organic solvents. Under conditions for catalysis, the acetate group is lost and the Pd-C bond undergoes protonolysis, giving rise to a source of "".
The complex is made by reaction of tris(o-tolyl)phosphine with palladium(II) acetate:
Many analogues of Hermann's catalyst have been developed, e.g. palladacycles obtained from 2-aminobiphenyl.
References
Organopalladium compounds
Dimers (chemistry)
Phosphine complexes | Herrmann's catalyst | [
"Chemistry",
"Materials_science"
] | 147 | [
"Dimers (chemistry)",
"Polymer chemistry"
] |
59,499,249 | https://en.wikipedia.org/wiki/Saudi%20Space%20Agency | The Saudi Space Agency (SSA; ), previously known as the Saudi Space Commission (SSC), is a Saudi independent government entity established by a royal order on December27, 2018 and elevated to an agency on June 14, 2023. The agency is chaired by Abdullah Alswaha, the Saudi Minister of Communications and Information Technology.
On July 17, 2024 it was reported that the Saudi Space Agency signed a space agreement with NASA to collaborate on civilian space research and explorations. This is another step forward on the country's ambition to create a robust space sector.
Spaceflights
Prior to the establishment of the Saudi Space Agency, the only Saudi astronaut was prince Sultan bin Salman Al Saud, who flew aboard the Space Shuttle Discovery in 1985 as a Payload Specialist on STS 51-G.
In 2022, the SSA partnered with American private spaceflight company Axiom Space to send two Saudi astronauts, including the first Saudi woman in space, to the International Space Station aboard a SpaceX Crew Dragon as part of Axiom Mission 2. The astronauts selected were Ali AlQarni and Rayyanah Barnawi, with Ali AlGhamdi and Mariam Fardous as backups.
List of SSA astronauts
See also
List of government space agencies
List of Arab astronauts
Axiom Mission 2
References
Government of Saudi Arabia
Space agencies
Government agencies established in 2018
2018 establishments in Saudi Arabia | Saudi Space Agency | [
"Astronomy"
] | 284 | [
"Astronomy stubs",
"Astronomy organizations",
"Astronomy organization stubs"
] |
59,500,109 | https://en.wikipedia.org/wiki/Correlation%20function | A correlation function is a function that gives the statistical correlation between random variables, contingent on the spatial or temporal distance between those variables. If one considers the correlation function between random variables representing the same quantity measured at two different points, then this is often referred to as an autocorrelation function, which is made up of autocorrelations. Correlation functions of different random variables are sometimes called cross-correlation functions to emphasize that different variables are being considered and because they are made up of cross-correlations.
Correlation functions are a useful indicator of dependencies as a function of distance in time or space, and they can be used to assess the distance required between sample points for the values to be effectively uncorrelated. In addition, they can form the basis of rules for interpolating values at points for which there are no observations.
Correlation functions used in astronomy, financial analysis, econometrics, and statistical mechanics differ only in the particular stochastic processes they are applied to. In quantum field theory there are correlation functions over quantum distributions.
Definition
For possibly distinct random variables X(s) and Y(t) at different points s and t of some space, the correlation function is
where is described in the article on correlation. In this definition, it has been assumed that the stochastic variables are scalar-valued. If they are not, then more complicated correlation functions can be defined. For example, if X(s) is a random vector with n elements and Y(t) is a vector with q elements, then an n×q matrix of correlation functions is defined with element
When n=q, sometimes the trace of this matrix is focused on. If the probability distributions have any target space symmetries, i.e. symmetries in the value space of the stochastic variable (also called internal symmetries), then the correlation matrix will have induced symmetries. Similarly, if there are symmetries of the space (or time) domain in which the random variables exist (also called spacetime symmetries), then the correlation function will have corresponding space or time symmetries. Examples of important spacetime symmetries are —
translational symmetry yields C(s,s') = C(s − s') where s and s' are to be interpreted as vectors giving coordinates of the points
rotational symmetry in addition to the above gives C(s, s') = C(|s − s'|) where |x| denotes the norm of the vector x (for actual rotations this is the Euclidean or 2-norm).
Higher order correlation functions are often defined. A typical correlation function of order n is (the angle brackets represent the expectation value)
If the random vector has only one component variable, then the indices are redundant. If there are symmetries, then the correlation function can be broken up into irreducible representations of the symmetries — both internal and spacetime.
Properties of probability distributions
With these definitions, the study of correlation functions is similar to the study of probability distributions. Many stochastic processes can be completely characterized by their correlation functions; the most notable example is the class of Gaussian processes.
Probability distributions defined on a finite number of points can always be normalized, but when these are defined over continuous spaces, then extra care is called for. The study of such distributions started with the study of random walks and led to the notion of the Itō calculus.
The Feynman path integral in Euclidean space generalizes this to other problems of interest to statistical mechanics. Any probability distribution which obeys a condition on correlation functions called reflection positivity leads to a local quantum field theory after Wick rotation to Minkowski spacetime (see Osterwalder-Schrader axioms). The operation of renormalization is a specified set of mappings from the space of probability distributions to itself. A quantum field theory is called renormalizable if this mapping has a fixed point which gives a quantum field theory.
See also
References
Covariance and correlation
Time series
Spatial analysis | Correlation function | [
"Physics"
] | 833 | [
"Spacetime",
"Space",
"Spatial analysis"
] |
62,133,515 | https://en.wikipedia.org/wiki/Maiken%20Mikkelsen | Maiken Mikkelsen is a physicist who won the Maria Goeppert Mayer award from the American Physical Society in 2017 for her work in quantum nanophotonics. She is currently the James N. and Elizabeth H. Barton Associate Professor of Electrical and Computer Engineering and an associate professor of physics at Duke University where she teaches ECE 891: internship and ECE 524: introduction to solid state physics. Mikkelsen is credited for many advancements in optoelectronics, nanophotonics, human health and the environment.
Education
Maiken Mikkelsen received her B.S. in physics in 2004 from the University of Copenhagen. She received her Ph.D. in physics in 2009 from the University of California, Santa Barbara, where she studied single electron spin dynamics in semiconductors for her Ph.D. thesis and for which she won the 2011 Thesis Prize from the Quantum Electronics and Optical Division (QEOD) of the European Physical Society. She did a postdoctoral research fellowship at the University of California at Berkeley before joining the faculty at Duke University in 2012.
Research interests
Mikkelsen's research focuses on light-matter interactions in nanophotonic structures, quantum materials, and novel multi-scale fabrication techniques. Her recent work in "Extreme Nanophotonics" aims to realize unprecedented material properties and behavior by sculpting electromagnetic fields on the molecular scale.
List of awards and honors
MURI Award (PI), AFOSR (2021)
Stansell Family Distinguished Research Award, Duke University (2021)
American Chemical Society (ACS) Photonics Young Investigator Award (2020)
Moore Inventor Fellow Award, Gordon and Betty Moore Foundation (2019)
National Institutes of Health (NIH) RO1 Award (2019)
Maria Goeppert Mayer Award, American Physical Society (2017)
Early Career Achievement Award, SPIE (International Society for Optics and Photonics) (2017)
Young Investigator Program (YIP) Award, Office of Naval Research (2017)
Young Investigator Program (YIP) Award, Army Research Office (2016)
Cottrell Scholar Award, Research Corporation for Science Advancement (2016)
Scialog Fellow, Research Corporation for Science Advancement (2016)
CAREER Award, National Science Foundation (2015)
Young Investigator Program (YIP) Award, Air Force Office of Scientific Research (2015)
Ralph E. Powe Junior Faculty Award (2014)
European Physical Society Ph.D. Thesis prize, Quantum Electronics and Optics (2011)
NSF ADVANCE Award, Workshop for Women in Science & Engineering (2009)
Center for Nanoscience Innovation for Defense (CNID) Graduate Fellowship (2007)
Major scientific achievements
Revealed record-high spontaneous emission rates. Elucidated the mechanisms behind large Purcell factors and demonstrated record-high 1,000-fold enhancement in the spontaneous emission rate of dye molecules and semiconductor quantum dots (Nature Photonics 8, 835 (2014), Nature Communications 6, 7788 (2015)).
Realized first ultrafast and efficient single photon source. Realized this long-sought goal by embedding single quantum dots in plasmonic cavities. Critical to quantum information and quantum optics communities, as the natural slow emission rate of single photon sources is a limiting factor for many experiments and future applications (Nano Letters 16, 270 (2016)).
Demonstrated first ultrafast, spectrally-selective thermal photodetector. Utilized metasurfaces to create spectrally-selective perfect absorption enabling the use of an only 100 nm pyroelectric thermal detection layer and revealing speeds of <700 ps, an improvement of five-orders-of-magnitude over state-of-the-art. The metasurface also acts as an on-chip spectral filter promising for hyperspectral imaging (Nature Materials 19, 158 (2020)).
Created novel multi-scale fabrication technique to realize large-area structural color. Utilized chemical self-assembly to achieve sub-10 nm gaps between metals to demonstrate spectrally-selective perfect absorbers. Combined with top-down large-scale patterning to realize multi-spectral pixels and ~10,000 plasmonic combinatorial colors. Promising for transformative breakthroughs of e.g. photodetectors and imaging devices (Advanced Materials 27, 8028 (2015), Advanced Materials 29, 1602971 (2017)).
Explained the benefit of nanogap cavities for point-of-care immunoassays. Integrated a sandwich immunoassay microarray within a plasmonic nanogap cavity resulting in a 151-fold increase in fluorescence and 14-fold improvement in the limit-of-detection for the cardiac biomarker B-type natriuretic peptide (BNP). (Nano Letters 20, 4330 (2020), Advanced Materials 35, 2107986 (2023)).
Publications
Her most cited publications are:
(cited 1118 times according to Google Scholar
(cited 376 times according to Google Scholar)
(cited 498 times according to Google Scholar)
(cited 463 times according to Google Scholar)
(cited 488 times according to Google Scholar)
References
External links
Faculty profile
Mikkelsen Lab site
MURI:Meta-Imaging
Google Scholar profile
21st-century women physicists
Duke University faculty
University of Copenhagen alumni
University of California, Santa Barbara alumni
Year of birth missing (living people)
Living people | Maiken Mikkelsen | [
"Materials_science"
] | 1,108 | [
"Metamaterials scientists",
"Metamaterials"
] |
62,134,998 | https://en.wikipedia.org/wiki/3MM-1 | 3MM-1 (also known as COS-3mm-1) is a star-forming galaxy about 12.5 billion light-years away that is obscured by clouds of dust. It is located in the constellation of Sextans. It was first detected in spectroscopic data on rotational transitions of carbon monoxide obtained using the Atacama Large Millimeter Array from 23-24 December 2018, as detailed in an article that was published on 22 October 2019. The authors of this article described the discovery as "serendipitous", since the focus of their planned observations had been on galaxies at redshifts near 1.5 that are quiescent — i.e. do not form stars — and directly observable, yet 3MM-1 was found at a redshift of about 5.5, is forming stars and not directly observable. In the same dataset, another dust-obscured star-forming galaxy, 3MM-2, was found at a redshift of about 3.3.
In early 2021, a more precise estimate of 3MM-1's redshift was published, according to which the value is z = 5.857 ± 0.001.
3MM-1 has a mass of about 1010.8 solar masses, and stars form in it at about 100 times the rate as in the Milky Way.
References
Galaxies
Sextans | 3MM-1 | [
"Astronomy"
] | 293 | [
"Galaxy stubs",
"Galaxies",
"Sextans",
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62,135,111 | https://en.wikipedia.org/wiki/Ilona%20Banga | Ilona Banga (1906–1998) was a Hungarian biochemist known for co-discovering actomyosin and working to characterize how actin and myosin interact to produce muscle contraction. She and her husband József Mátyás Baló discovered the first elastase – an enzyme capable of degrading the protein elastin which gives tissues like veins their flexibility. She also contributed to work that earned Albert Szent-Györgyi the Nobel Prize in Physiology or Medicine in 1937, including by developing methods for the purification and characterization of large quantities of vitamin C. During World War II she saved the equipment of the Institute of Chemistry of the University of Szeged.
Early life and education
Banga was born February 3, 1906, in the southeastern Hungarian town of Hódmezővásárhely. She was interested in becoming a medical doctor but chose instead to study chemistry because her mother didn't think medical doctor was a proper profession for a woman.
She started studies in Szeged, continued at the University of Vienna and received an MSc in chemistry from the University of Debrecen in 1929. At the University of Debrecen she carried out Physiology research under the guidance of professor Fritz Verzár.
Career
After graduating, she joined the laboratory of Albert Szent-Györgyi at the University of Szeged's Institute for Medicinal Chemistry as a research assistant – she was the first associate for this future Nobel laureate. Banga worked with Szent-Györgyi for almost fifteen years, resulting in 25 joint publications. Banga later spent time working abroad in Liege, Belgium, and Oxford, England. While in Oxford she worked with another future Nobel laureate, Severo Ochoa to study vitamin B1.
In 1945, Albert Szent-Györgyi moved his lab from Szeged to Budapest and Banga followed him there. She later became chief of the Chemical Laboratory of the First Institute of Pathological Anatomy in Budapest, where she studied arteriosclerosis and aging with her husband József Baló. She retired in 1970. After retiring she remained engaged in the scientific community, serving as a scientific advisor to the Gerontology Institute from 1971 to 1986.
Banga was never made a professor, even though (in 1950) she received her DSc degree, making her eligible. She was, however, the first woman to achieve the rank of docent (comparable to associate professor) at the University of Szeged (1940). She authored two scientific texts, including Structure and Function of Elastin and Collagen, and was a founder member of the Hungarian Biochemical Society.
Research
Banga's initial work as Szent-Györgyi's associate involved studying carbohydrate metabolism. She developed methods for the large-scale purification of ascorbic acid (vitamin C) from Hungarian paprika – work that entailed extracting the vitamin from close to a metric ton of paprika. After winning the Nobel Prize in Physiology or Medicine in 1937 (for work to which Banga contributed), Albert Szent-Györgyi switched his lab's focus to researching muscle contraction, motivated by the findings of Engelhardt and Ljubimova that the muscle protein myosin wasn't merely a structural protein – it had phosphatase (ATPase) activity. Banga confirmed these findings and further characterized myosin's ability to split ATP. In the process, she co-discovered actomyosin.
In order to get myosin to analyze, Banga extracted it from rabbit muscles – she minced rabbit muscles and extracted myosin from them following an established high salt protocol. One time she ran out of time to do the extraction and left the minced muscle sitting in saline overnight and when she came back the next morning it had changed from its usual thin liquid appearance to a thick, viscous solution. They found that if they added ATP to it the viscosity would decrease. Further work by another lab member, Brunó Straub, showed that Banga had extracted a combination of actin and myosin, which they called actinomyosin. Straub was able to isolate the actin and he, Banga, and other members of the lab carried out extensive characterization of actin, myosin, and actinomyosin, showing that it is responsible for muscle contraction.
The widespread distribution of their findings was hampered by World War II – Szent-Györgyi was wanted for anti-Nazi activities and went into hiding, and other male colleagues left the lab to escape drafting. Banga remained behind and saved the Department of Medicinal Chemistry and its equipment by posting signs on the door in German, Hungarian, and Russian identifying the facilities as an infectious disease laboratory and reporting hours for the drop-off of infectious materials. These signs warded off would-be thieves and made the Department of Medicinal Library the only institution at the University to come out of WWII with all of its equipment and facilities preserved.
Albert Szent-Györgyi left Hungary for the United States after the war, but Ilona stayed and became chief of the Chemical Laboratory of the First Institute of Pathological Anatomy in Budapest. The new position also came with a shift in focus – she became deeply involved in gerontology, the study of aging, with a specific interest in how the connective tissue of blood vessel walls changes with age. She carried out seminal work on arteriosclerosis with her husband József Mátyás Baló. One area of their investigation determining what causes degradation of the elastin fibers holding together the walls of veins. They discovered an enzyme made by the pancreas could degrade elastin and named it elastase. This is now known to be only one of a class of peptidases capable of cleaving elastin, and the pancreatic elastase Banga and Baló found is unlikely to play a role in arteriosclerosis, but it was the first elastolytic enzyme discovered. The discovery was met with skepticism initially, but, by crystallizing elastase, Banga was able to clear up doubt. Banga further characterized this enzyme and published more than 60 articles on elastase, elastin, and related molecules and processes during the period from 1948 to 1965.
Personal life
Banga married the pathologist József Mátyás Baló in Szeged in 1945, working closely with him on research on arteriosclerosis until his death in 1979. The couple had a son, Mátyás Jr., who became an academic dermatologist. Banga died March 11, 1998.
Honors and awards
Banga was awarded the Kossuth Prize in 1955 for her discovery of elastase – it was offered to her in 1952 but in what's believed to be an oversight, her husband and co-discoverer József Mátyás Baló was not included so, responding that the work was a joint effort, she declined the offer, accepting it in 1955 when the offer was made to the pair of them. She was the first awardee of the University of Szeged's Albert Szent-Györgyi Commemorative Medal (1986) and was elected to the Leopoldina Academy in Halle, East Germany in 1962.
Selected works
"Myosin and Muscular Contraction" – in this report, Banga et al. describe their groundbreaking experiments leading to the discovery of actomyosin
These archives contain Studies from the Institute of Medical Chemistry University Szeged – reports published by Banga and others in the Szent-Gyorgi laboratory during WWII
References
1906 births
1998 deaths
20th-century biochemists
Hungarian biochemists
Hungarian women scientists
People from Hódmezővásárhely
Women biochemists | Ilona Banga | [
"Chemistry"
] | 1,620 | [
"Biochemists",
"Women biochemists"
] |
62,136,161 | https://en.wikipedia.org/wiki/Composable%20disaggregated%20infrastructure | Composable disaggregated infrastructure (CDI), sometimes stylized as composable/disaggregated infrastructure, is a technology that allows enterprise data center operators to achieve the cost and availability benefits of cloud computing using on-premises networking equipment. It is considered a class of converged infrastructure, and uses management software to combine compute, storage and network elements. It is similar to public cloud, except the equipment sits on premises in an enterprise data center.
Overview
American market intelligence firm International Data Corporation (IDC) describes CDI as "an emerging category of infrastructure systems that make use of high-bandwidth, low-latency interconnects to aggregate compute, storage, and networking fabric resources into shared resource pools that can be available for on-demand allocation."
These systems use what is sometimes called rack-scale architecture, which allows network operators to replace components on a rack while the entire data center behaves as a virtualized server. This allows operators to allocate compute, memory, and storage resources inside each server node on-demand, over a high speed, low latency computing fabric. The individual components can be managed as a resource pool, allowing dynamic provisioning and deprovisioning with a common application programming interface (API). No hardware configuration is required.
Technology
Composability refers to the composer, which is another term for the software that allows the server resources, which include compute, storage, and RAM, to be placed into a pool to become available for applications and workloads. Disaggregation is the process of aggregating server resources with the resources of other servers in the data center. These aggregated or pooled resources can be shared by applications or workloads. The composer software controls how much of each disaggregated resource is needed from each server.
The use of software APIs to provisioning the resources without having to directly program any individual hardware device is known as programmatic control. Operators can use open APIs in composable infrastructure in order to integrate third-party software and hardware with proprietary solutions.
References
Computing terminology
Network architecture
Data centers
IT infrastructure | Composable disaggregated infrastructure | [
"Technology",
"Engineering"
] | 437 | [
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62,137,449 | https://en.wikipedia.org/wiki/Wittenberg%20interpretation%20of%20Copernicus | The Wittenberg Interpretation refers to the work of astronomers and mathematicians at the University of Wittenberg in response to the heliocentric model of the Solar System proposed by Nicholas Copernicus, in his 1543 book De revolutionibus orbium coelestium. The Wittenberg Interpretation fostered an acceptance of the heliocentric model and had a part in beginning the Scientific Revolution.
In 1543, Nicholas Copernicus changed the scientific world by publishing De revolutionibus orbium coelestium. This was the first time that a heliocentric model had seriously been considered, and publicised, and a resulted in a slew of opinions on how the universe may work. One such place that these debates existed was the University of Wittenberg which was home to many astronomers, astrologists and mathematicians, such as Erasmus Reinhold, Philip Melanchthon, Caspar Peucer, Georg Rheticus, and Albrecht Hohenzollern. The work of such figures became known as the Wittenberg Interpretation, which historians recognise as important in fostering acceptance for the heliocentric explanation of the universe, and the wider shift of public views over time; and the beginning of the Scientific Revolution.
Philipp Melanchthon
Philipp Melanchthon entered Wittenberg studying theology, becoming a leading figure in the Lutheran reformation of the school. During this reformation, Melanchthon introduced many courses in mathematics to Wittenberg, in addition to several other universities. His teachings included Ptolemy's Librorum de judiciis astrologicis, and emphasized a connection between astronomical events and God. In 1536, Melanchthon appointed Georg Joachim Rheticus and Erasmus Reinhold, two of his previous students, to chairs of Lower and Higher Mathematics. Many scholars studied under and worked alongside Melanchthon however, Rheticus and Reinhold, in addition to Caspar Peucer, were considered the most vital members of the Melanchthon circle, also referred to as the Wittenberg circle. The men in this circle were astronomers who, under Melanchthon’s leadership, formed analysis of Copernican theory based on theory published in De revolutionibus.
Philipp Melanchthon and Copernican Theory
Prior to the Copernican theory, Melanchthon strongly agreed with the work of Aristotle and Ptolemy. Melanchthon first became familiar with Copernican theory through Rheticus’ Narratio prima in 1540. He first took the stance that Copernican’s theory was absurd. Melanchthon’s lectures tended to reject Copernican theory as it seemed to conflict with scripture, and advised students to avoid it. Later lectures show that Melanchthon’s views may have changed slightly, as he applauds Copernicus’ lunar theory and suggests it is worth looking at. However, Melanchthon continues to recommend that his students remain concerned with Ptolemaic lunar theory, as he had been teaching up to this point. Melanchthon agrees that the Earth could possibly move and rotate like Copernicus suggests even though it does not agree with the scripture. Throughout his time studying and lecturing on Copernican theory, Melanchthon never ignores the fact that Copernicus defies scripture, an idea which Melanchthon openly disapproves of. However, Melanchthon seems to agree that this new theory has value to the subject of astronomy and there must be something worth learning from Copernican's theory and therefore doesn’t reject it entirely. Like the members of the Melanchthon circle, Melanchthon himself does not fully accept or fully reject Copernican theory, but is instead more moderate. His moderate stance allowed others to view Copernican’s theory from an open point of view.
Caspar Peucer
Caspar Peucer (1525–1602) entered the University of Wittenburg in 1540. There, he studied astronomy, mathematics, and medicine under the teachings of Philipp Melanchthon, Erasmus Reinhold and Georg Joachim Rheticus. Shortly thereafter, he became a professor at the university and the son-in-law of Melanchthon when he married his daughter Magdalena. Considered one of the most important disciples to carry on the teachings of Melanchthon, he eventually held a high position within the university and was able to convey the Melanchthon Circle’s interpretations of the Copernican theory. Peucer is accredited with being able to effectively consolidate and institutionalize the Wittenburg Interpretation at German universities. He was able to do this by choosing to place Philippists (partisans of Melanchthon) in influential positions instead of orthodox Lutherans. This strategic placement eventually lead to a power struggle which resulted in Peucer being charged with being a crypto-Calvinist and incarcerated in 1576. After his incarceration, his work in astronomy ceased and he focused on practicing medicine.
Caspar Peucer and Copernican Theory
While teaching the curriculum to entry-level natural science students the importance of teaching arithmetic, physics, and astrological teachings of Aristotle, Pliny, Sacrobosco, and Ptolemy was emphasized. An introduction to the Copernican theory was also included within the curriculum, although limited. Peucer mainly cited Copernican quantitative material in order to help explain celestial motions, even though it was different from scripture, and to discuss absolute distances of the sun, moon and earth. He also utilized Copernican data to discuss eclipses and the length of the day. In Peucer’s teachings, the findings of Copernicus could not be utilized in extensive arguments because he was considered to be aligned with the theory of Aristarchus. Peucer thought that Copernicanism was offensive and should not be taught in education; however, although Peucer’s views did not align with Copernican theory, he still had to teach and advised his students to consider Copernican theory because it was a scientific theory.Peucer's views on Copernican theory mirrored the views of his mentors Melanchthon and Reinhold. Between the members of the Melanchthon Circle, each instructor made up a different pedagogic element in the Wittenberg Interpretation. An element of the interpretation that all of the members could agree in teaching was that only a dedicated scholar is capable of understanding astrology and the celestial elements that drive it. Caspar Peucer was particularly determined to examine the properties of celestial "qualitates occultae". Notably, the members of the circle admired the teachings of Italian scholars, with Rheticus supporting the views of Girolamo Cardano, and Peucer being well read in the works of Pietro Pomponazzi.
Peucer in particular supported Martin Luther's opposition of Aristotle's view on natural philosophy. He strongly believed that unusual events that did not follow the natural laws was due to divine intervention either by God or the devil. Copernicus's heliocentric theory was inspired by the research of Aristotle and firmly followed the laws of natural science without consideration for divine intervention. That being said, at the introductory level Copernican theory was not entertained extensively because Peucer and other members of the circle believed the mechanisms to be too advanced for an introduction to planetary movements. At the Masters level, Copernican theory was covered more in depth, as well as treated with the same serious consideration Ptolemaic theory received. This higher, in depth level of Copernicans theory was likely taught by pupils of Peucer. Peucer thought that the Copernican theory, heliocentric model could be interpreted in a geocentric way without changing the original hypotheses. Peucer's work Hypotyposes orbium coelestium states that the Copernican model could be utilized if two more spheres were added. While Caspar Peucer acknowledges that the models and theories of Ptolemy are geometrically accurate, the absence of cosmological choice and incorporation of scriptural arguments made the theories lacking. The issues Peucer had with the work of Copernicus are similar to the Church's trouble with the work of Galileo Galilei that landed him in trouble. Ironically, the ideas that got Peucer in jail were his views on Holy Communion.
Erasmus Reinhold
Erasmus Reinhold was born in Saalfeld, Saxony in 1511. In 1536, Philipp Melanchthon appointed Reinhold to professor of higher mathematics, a subject which included astronomy, at the University of Wittenberg where Reinhold had previously studied. Reinhold initially became acquainted with Copernican theory through the writings of Georg Joachim Rheticus, an astronomer and colleague who also worked closely with Melanchthon at the University. Before De Revolutionibus orbium coelestium was published, Reinhold gained information regarding Copernican theory, specifically regarding the movement of the moon, from Narratio prima. This book was written by Rheticus, and provided his analysis of Copernican theory. Reinhold believed in uniform circular motion and that two equal and regular circular motions will create a motion in a straight line, an infinite opposite motion, and an unequal motion where it is slower towards the outside than it is in the center. Based on his knowledge of Copernicus’s lunar theory, gained from Rheticus's Narratio prima, Reinhold praised Copernican theory. This is seen in Reinhold’s annotations within Peurbach’s New Theorics of the Planets, published in 1542. In these notes, Reinhold mentions his dissatisfaction with the lack of understanding in modern astronomy, yet also mentions how Copernicus’s lunar theory restores his hope. In additional annotations, Reinhold continually mentions how new Copernican theory simplifies astronomical motion by erasing the need for an equant, an idea previously introduced by the geocentric model of the Ptolemaic system. Reinhold was very impressed by Copernicans ability to remove the equant in his theory of the cosmos. This new idea, the rejection of the equant, is the source of Reinhold’s praise of Copernicus and Copernican theory, as it simplifies planetary motion and in his opinion, allows for the future of astronomy to move forward in a smoother, less confusing or cluttered manner. He believed God had allowed Copernicus to discover the movement celestial beings and remove the equant even though it was different from the scripture of the time.
After the publication of De revolutionibus orbium coelestium in 1543, Reinhold remained relatively neutral on the issue of a heliocentric versus a geocentric cosmos. However, he wanted to recalculate and provide clean and simple-to-read tables based on the new ideas of motion presented in De revolutioninus. Reinhold did exactly this as he wrote and published the Prutenic Tables. He utilized Copernicans observational data, even though he did not agree with Copernicans heliocentric cosmos, and created the tables based upon Copernicans planetary mechanisms. Melanchthon thoroughly supported this new compilation of tables of motion, and even helped secure funding from Albrecht, the Duke of Prussia, for the publishing the Prutenic Tables.
Georg Joachim Rheticus
Georg Joachim Rheticus, most commonly known as Rheticus, was well known for his trigonometric tables and considered a pupil of Copernicus. He was born on February 16, 1514, in Feldkirch, in present day as Austria. After his father’s execution, Rheticus went on to study at the Latin school in Feldkirch, then went to Zurich where he attended the Frauenmuensterschule from 1528 to 1531. In 1533, he began his studies at the University of Wittenberg. Then in 1536, Philipp Melanchthon, an influential educator in Germany, appointed Rheticus appointed Rheticus as the chair of Lower Mathematics to teach astronomy and mathematics at Wittenberg. Two years after being appointed, Rheticus was given a two year leave of Wittenberg to study alongside other well-known astronomers at that time. His colleagues at Wittenberg described Rheticus’s personality as abnormal and enthusiastic, with homosexual tendencies. They perceived Rheticus as a man who would get caught up by the fame and knowledge of older men, and would fantasize about them. This led them to believe that was the sole purpose of Rheticus asking Melanchthon for the leave of absence from Wittenberg was for Rheticus to become closer to Copernicus. Rheticus’s fantasy to work with Copernicus may have been true. However, several factors suggest that Rheticus first learned of Copernicus during his travel across Germany in late 1538. After these two met, their relationship grew strong through sharing revolutionary ideas. Rheticus ended up staying with Copernicus for two and a half years. Rheticus had acquired a father figure in Copernicus and Copernicus acquired the only real student he would ever have.
Rheticus and Copernican theory
Unlike the other students of Melanchthon, Reinhold and Peucer, who doubted Copernicus’s theory, Rheticus praised Copernicus for asserting an ‘absolute system’ of the planets. In 1540, Rheticus wrote the De libris revolutionum Copernici narratio prima, commonly known as Narratio prima, an introduction to the theories of Copernicus. Along with the publication, he visited a publisher and printer in Nuremberg in order to push Copernicus to publish his work De Revolutionibus orbium coelestium. Copernicus developed his heliocentric theory after realizing that the retrograde motion of the planets could be explained much better without epicycles, with the Earth orbiting the Sun rather than the other way around. Rheticus believed that the heliocentric universe should be adopted because it could explain the phenomena of the precession of the equinoxes and the change in the obliquity of the ecliptic. If the Sun was the center of the deferents of the planets, it allowed the circles in the universe to revolve uniformly and regularly, it united all the spheres into one system, and it was a simpler model with fewer explanations necessary. Rheticus also accepted Copernicans' idea of the moon moving on and epicycle rather than its movement on an equant (1). Rheticus's time visiting Copernicus allowed for his theory to become known since he was able to push Copernicus into publishing his work to be read by others.
Wittenberg textbooks emphasized the problems of the Copernican theory and how it related to the calendar, lunar motion, and the rejection of the equant. The Narratio prima also contained ideas that were not found in De revolutionibus or in any of Copernicus’s other writings. The book emphasized the demonstration of a system in the necessary interconnexity of the relative distance and periods of the planets, a problem in the Copernican theory that the textbooks did not mention. Rheticus claimed that a common measure was established to explain how the planets were geometrically aligned and arranged so that no immense interval was left between one and the other. His claim made three assumptions about the planetary models: that each planet is carried by a uniformly revolving sphere, that the principle of plenitude states, there are no gaps between the spheres, and that the relative planetary positions are to be measured with respect to a common unit. He wanted to eliminate the earth’s projected motion which appeared as the epicycles in earth-centered planetary models, allowing for the planets to be placed continuously based on their mean periodic motions.
Copernicus and Rheticus both knew that there would be backlash. One theologian, Andreas Osiander, in order to forestall censorship of Copernicus's work, wrote an anonymous preface that described the work as a pure hypothesis. Rheticus became furious and crossed out the preface in those copies of De revolutionibus that he came across. The Church also emphasized that Copernicus’s theory was against scripture and believed that the world revolved around the Earth and were persistent with the Earth being in the center. Some science was frowned upon by the church because it was uncertain in the Bible, and certain knowledge of physics is not necessary to human salvation. However, knowledge of astronomy is demanded of great men by God. The Copernican theory indicates that the earth is a planet, that all planets have defects, and all are subject only to circular motions. Rheticus argues that these characteristics are not a physical problem but a mathematical one. With this claim, he aimed to shift the perspective of the Church so that the theory could be explained mathematically, which would be more acceptable since it represented direct testimony of God’s Providence and God gave clues to it in Scripture.
Albrecht Hohenzollern
Albrecht (Albert), Duke of Prussia was not only the first Duke of Prussia, but also a Lutheran, who believed strongly in the importance of students learning mathematics, astronomy, and other scientific topics. Religion was a very important part of Albrecht’s life: his rule of Prussia was crucial to the spread of Lutheranism, as he was the first leader in Europe to rule his people under it. It is somewhat surprising that Albrecht remained so interested and invested in the sciences, as there were many debates at the time as to whether or not the new astronomical considerations went against the views of the world in the Bible. Despite these conflicts, Albrecht was a fairly well-liked ruler. His religious beliefs led to him acting as a “protector” of sorts, and at various times he supported both Rheticus and Reinhold. The Prutenic Tables are named in his honor.
Albrecht's Influence at Wittenberg
One reason Albrecht was able to balance his religious and scientific beliefs was his close personal relationship with Philip Melanchthon, which helped to further shape his belief in these scientific systems, causing him to even go so far as to appointment a court astrologer, Johann Carion. Albrecht was also considered a very important “protector” of people like Copernicus and Rheticus. As he was a Protestant/Lutheran, these men knew that he had the power to protect them from being charged with the crime of spreading beliefs that went against the current interpretation of the Bible. In April of 1540, Albrecht’s associate, Giese, sent to Albrecht a copy of Rheticus's Narratio prima, which included very high praise of Prussia, and a request by Rheticus to come study and continue his work in Prussia, specifically at Albrecht's court. However, he also hinted at the fact that he wanted to be protected, as he was a Lutheran and knew that Albrecht was as well. Despite the fact that Albrecht had never heard of this new mathematician before, he obliged: he sent back a “lisbonino”, which was a gold coin that was meant for showcasing, rather than being used as currency. This was a truly important move, as it allowed Rheticus to continue his studies and work in Prussia, and led to Rheticus's later appointment at Leipzig. Albrecht’s contribution to the Wittenberg interpretation was one that had profound implications. Allowing Rheticus to come to Prussia allowed him to further his own studies, which in turn solidified the heliocentric model.
Conclusion
Most of the astronomers and mathematicians at Wittenberg (Melanchthon, Peucer, Reinhold) took a more moderate stance toward the Copernican theory and only accepted parts of it to be true. This was due to the fact that most of Copernican’s ideas went against the scripture at the time and having ideas that were different from the scripture were frowned upon and not easily accepted. However, Rheticus strongly supported Copernicus after visiting with him and his time studying in Prussia alongside Albrecht. Rheticus came to the conclusion that Copernican’s heliocentric model made more sense than the previous geocentric model suggested by Ptolemy. His open views on the Copernican theory allowed others to be able to view the theory with an open mind. While all the teachers at the University of Wittenberg had different ideas and acceptances of the cosmos they all taught their students about both Ptolemy’s cosmos and Copernican’s cosmos to give their students a well-rounded education. Overall, the Wittenberg Interpretation changed the way astronomers and mathematicians viewed the heliocentric and geocentric models of the cosmos and how it was taught throughout German universities.
References
Bibliography
Barker, Peter, Tredwell, Katherine Anne. (2005). The exact sciences in Lutheran Germany and Tudor England. .
Brosseder, Claudia (2005). "The Writing in the Wittenberg Sky: Astrology in Sixteenth-Century Germany". Journal of the History of Ideas. 66(4): 557–576. .
Copernicus, Nicolaus (1952), On the Revolutions of the Heavenly Spheres, Great Books of the Western World, 16, translated by Charles Glenn Wallis, Chicago: William Benton
Danielson, Dennis Richard (2006-10-31). The First Copernican: Georg Joachim Rheticus and the Rise of the Copernican Revolution. Bloomsbury Publishing USA. .
Evans, James (December 1984). "On the function and the probable origin of Ptolemy's equant". American Journal of Physics. 52 (12): 1080–1089. .
Gingerich, Owen (1973). "From Copernicus to Kepler: Heliocentrism as Model and as Reality". Proceedings of the American Philosophical Society. 117 (6): 513–522. .
Gingerich, Owen (1973). "The role of Erasmus Reinhold and the Prutenic Tables in the Dissemination of Copernican Theory", Studia Copernicana, 6
Grafton, Anthony (2017). "The Middleman:. American Scientist. 2017-02-06.
Kraai, Jessse (200). "Rheticus' Heliocentric Providence: a study concerning the astrology, astronomy of the sixteenth century".
Rabin, Sheila (2019), Zalta, Edward N. (ed.), "Nicolaus Copernicus", The Stanford Encyclopedia of Philosophy (Fall 2019), Metaphysics Research Lab, Stanford University.
Vermij, Rienk (2010). "A Science of Signs. Aristotelian Meteorology in Reformation Germany". Early Science and Medicine. 15 (6): 648–674. .
Westman, Robert S. (1975). "The Melanchthon Circle, Rheticus, and the Wittenberg Interpretation of the Copernican Theory". Isis. 66 (2): 165–193. .
Westman, Robert S. (2011). "The Copernican Question: Prognostication, Skepticism, and Celestial Order"
Ferry, Patrick T. (1993). "The Guiding Lights of the University of Wittenberg and the Emergence of Copernican Astronomy". Concordia Theological Quarterly.
Tupikova, Irina and Omodeo, Pietro (2013) "The Post-Copernican Reception of Ptolemy: Erasmus Reinhold's Commented Edition of the Almagest, Book One (Wittenberg, 1549)". Journal for the History of Astronomy.
Copernican Revolution
Academic staff of the University of Wittenberg | Wittenberg interpretation of Copernicus | [
"Astronomy"
] | 4,924 | [
"Copernican Revolution",
"History of astronomy"
] |
62,138,896 | https://en.wikipedia.org/wiki/Halperin%20conjecture | In rational homotopy theory, the Halperin conjecture concerns the Serre spectral sequence of certain fibrations. It is named after the Canadian mathematician Stephen Halperin.
Statement
Suppose that is a fibration of simply connected spaces such that is rationally elliptic and (i.e., has non-zero Euler characteristic), then the Serre spectral sequence associated to the fibration collapses at the page.
Status
As of 2019, Halperin's conjecture is still open. Gregory Lupton has reformulated the conjecture in terms of formality relations.
Notes
Further reading
Homotopy theory
Spectral sequences
Conjectures | Halperin conjecture | [
"Mathematics"
] | 130 | [
"Unsolved problems in mathematics",
"Topology stubs",
"Conjectures",
"Topology",
"Mathematical problems"
] |
62,139,283 | https://en.wikipedia.org/wiki/The%20Seed%20%28organization%29 | The Seed was a controversial drug rehabilitation program in the United States that operated between 1970 and 2001. Aimed at youths, the program was modeled after adult treatment programs, with its techniques having been compared to those of the cult Synanon. In a 1974 U.S Senate report, its techniques were also compared to the North Korean brainwashing technique used on Prisoners of War during the Korean War. At its height in the 1970s The Seed had locations in Fort Lauderdale, Fort Myers, Dade County, and St. Petersburg. The organisation widely marketed itself as "spectacularly successful", "teaching love", and received wide press coverage. There was also a location in Cleveland, Ohio. Art Barker and his entourage would travel back and forth a couple times a month.
Following the release of the Senate report, along with criticisms from experts about the techniques and high suicide rate of the attendees, The Seed began to decline over the next two decades. By 2001, only the original Fort Lauderdale location remained, and the founder, Arthur Barker, retired and dissolved the organisation. Several other similar drug rehabilitation programs were founded in its image after The Seed's decline, most notably Straight, Incorporated.
References
Drug and alcohol rehabilitation centers
Behavior modification
Alcohol abuse
Drugs
Therapeutic community | The Seed (organization) | [
"Chemistry",
"Biology"
] | 251 | [
"Pharmacology",
"Behavior",
"Human behavior",
"Products of chemical industry",
"Behavior modification",
"Behaviorism",
"Chemicals in medicine",
"Drugs"
] |
62,139,505 | https://en.wikipedia.org/wiki/Vapor%20etching | Vapor etching refers to a process used in the fabrication of Microelectromechanical systems (MEMS) and Nanoelectromechanical systems (NEMS). Sacrificial layers are isotropically etched using gaseous acids such as Hydrogen fluoride and Xenon difluoride to release the free standing components of the device.
Economic advantages and novel technological possibilities result from micron to nano scale size reductions. (MEMS to NEMS) The small dimensions make the use of isotropic wet etch processes traditionally used in micro fabrication suffer from stiction, the permanent adherence of the free standing structure to the underlying substrate due to the scaling of surface effects occurring during the drying of the acid. Vapor etching overcomes stiction because no liquids are used during the etch process. Commonly, hydrogen fluoride and xenon difluorides are used to etch silicon dioxide and silicon sacrificial layers respectively.
HF vapor etching
The wet etching of SiO2 in buffered hydrogen fluoride solutions is a common and well understood process in micro fabrication. In 1966, Holmes and Snell found that SiO2 can be etched in hydrogen fluoride vapor. Initially the interest in this finding was low, because wet etch processes have higher etch rates and did not require sophisticated equipment. During the advent of MEMS technology and the consecutive reduction of size however, stiction started to have a significant impact on the production yields. Therefore HF vapor etching became an interesting commercial fabrication technology. Water or an alcohol catalysts are required, because anhydrous HF does not etch SiO2.
Etch chemistry
The etch chemistry depends on the catalyst used.
Etch reaction with water catalyst
If water is used, the H2O is adsorbed at the SiO2 surface and forms silanol groups can never form.SiO2 + 2 H2O → Si(OH)4 The HF reacts with the silanol groups and forms SiF4 and H2O according to the following reaction.Si(OH)4 + 4 HF → SiF4 + 4 H2OThe etch process commonly takes place at reduced pressures, to promote the desorption of the reaction products. Water is formed during the etch reaction. The efficient H2O removal is critical to prevent the formation of a liquid layer.
Etch reaction with alcohol catalyst
Alternatively, different alcohols such as methanol, ethanol, 1-propanol or IPA can be used to initiate the reaction. An example for this reaction, using methanol (CH3OH) is given below. Firstly the HF and the methanol are absorbed to the surface.CH3OH (g) ↔ CH3OH (ads)
HF (g) ↔ HF (ads)HF2- is formed by an ionization reaction of the absorbed HF and absorbed CH3OH2 HF (ads) + CH3OH (ads)-> HF2- (ads) + CH3OH2+ (ads)The ionized HF then reacts with the SiO2 according to the following reaction.SiO2(s) + 2 HF2- (ads) + 2 CH3OH2+ (ads) -> SiF4 (ads) + 2 H2O (ads) + 2 CH3OHFinally the reaction products are removed from the surface by desorption.
XeF2 vapor etching
Xenon difluoride, bromine trifluoride, chlorine trifluoride and fluorine can be used for gaseous silicon etching. Xenon difluoride is most commonly used to etch silicon in academia and industry, because it has a high selectivity towards other semiconductor materials, allows high process control and is easy to use at room temperature.
Etch systems
The synthesis of XeF2 is an endothermic process which results in a white powder which sublimes at low pressures. (P < 4 Torr) The low vapor pressure allowed early researchers and engineers to use it in comparatively simple set ups. Modern vapour etch tools are more sophisticated and are characterized by the way the gas is feed into the etch chamber. In pulsed systems the etchant is expanded, feed into the reaction chamber and remains there until it has been consumed by the reaction. Then the chamber is evacuated and this process is repeated for multiple cycles. In contrast to that, a carrier gas flows through a bubbler to continuously supply xenon difluoride into the etch chamber in continuous flow systems.
Etch chemistry
The general etch reaction is summarized by the following equation.2 XeF2 + Si → SiF4 + 2 XeThe detailed etch kinetic is more complex reaction consisting of four steps. After the etchant has been mass transported to the silicon surface, the xenon difluoride is absorbed on the silicon surface.2 XeF2 (gas) + Si (s) → 2 XeF2 (abs) + Si (s)The XeF2 disassociates into absorbed fluorine and gaseous Xe.2 XeF2 (abs) + Si (s) → 2 Xe (g) + 2 F (abs) + Si (s)The fluorine bonds with the surface silicon to form silicon tetra fluoride.2 Xe (g) + 2 F (abs) + Si (s) → 2 Xe (g) + SiF4 (ads)The reaction product is desorpted from the silicon surface.2 Xe (g) + SiF4 (ads) → " Xe (g) + SiF4 (g)The reaction products are mass transferred from the surface to the etch chamber, and ejected from there by a vacuum pump.
References
Electromechanical engineering | Vapor etching | [
"Engineering"
] | 1,228 | [
"Electrical engineering",
"Electromechanical engineering",
"Mechanical engineering by discipline"
] |
62,140,469 | https://en.wikipedia.org/wiki/H3K4me1 | H3K4me1 is an epigenetic modification to the DNA packaging protein Histone H3. It is a mark that indicates the mono-methylation at the 4th lysine residue of the histone H3 protein and often associated with gene enhancers.
Nomenclature
H3K4me1 indicates monomethylation of lysine 4 on histone H3 protein subunit:
Lysine methylation
This diagram shows the progressive methylation of a lysine residue. The mono-methylation (second from left) denotes the methylation present in H3K4me1.
Understanding 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. The basic structural unit of chromatin is the nucleosome: this consists of the core octamer of histones (H2A, H2B, H3 and H4) as well as a linker histone and about 180 base pairs of DNA. These core histones are rich in lysine and arginine residues. The carboxyl (C) terminal end of these histones contribute to histone-histone interactions, as well as histone-DNA interactions. The amino (N) terminal charged tails are the site of the post-translational modifications, such as the one seen in H3K4me1.
Mechanism and function of modification
H3K4me1 is enriched at active and primed enhancers. Transcriptional enhancers control the cell-identity gene expression and are important in the cell identity. Enhancers are primed by histone H3K4 mono-/di-methyltransferase MLL4 and then are activated by histone H3K27 acetyltransferase p300. H3K4me1 fine-tunes the enhancer activity and function rather than controls. H3K4me1 is put down by KMT2C (MLL3) and KMT2D (MLL4)
LSD1, and the related LSD2/KDM1B demethylate H3K4me1 and H3K4me2.
Marks associated with active gene transcription like H3K4me1 and H3K9me1 have very short half-lives.
H3K4me1 with MLL3/4 can also act at promoters and repress genes.
Relationship with other modifications
H3K4me1 is a chromatin signature of enhancers, H3K4me2 is highest toward the 5′ end of transcribing genes and H3K4me3 is highly enriched at promoters and in poised genes. H3K27me3, H4K20me1 and H3K4me1 silence transcription in embryonic fibroblasts, macrophages, and human embryonic stem cells (ESCs).
Enhancers that have two opposing marks like the active mark H3K4me1 and repressive mark H3K27me3 at the same time are called bivalent or poised. These bivalent enhancers convert and become enriched with H3K4me1 and acetylated H3K27 (H3K27ac) after differentiation.
Epigenetic implications
The post-translational modification of histone tails by either histone modifying complexes or chromatin remodelling complexes are interpreted by the cell and lead 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 the interactions of 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 characterised 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. Five core histone modifications were found with each respective one being linked to various cell functions.
H3K4me1- primed enhancers
H3K4me3-promoters
H3K36me3-gene bodies
H3K27me3-polycomb repression
H3K9me3-heterochromatin
The human genome was 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.
Clinical significance
Suppression of the H3K4 mono- and di-demethylase LSD-1 might extend lifespan in various species.
H3K4me allows binding of MDB and increased activity of DNMT1 which could give rise to CpG island methylator phenotype (CIMP). CIMP is a type of colorectal cancers caused by the inactivation of many tumor suppressor genes from epigenetic effects.
Methods
The histone mark H3K4me1 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.
See also
Histone methylation
Histone methyltransferase
Methyllysine
References
Epigenetics
Post-translational modification | H3K4me1 | [
"Chemistry"
] | 1,457 | [
"Post-translational modification",
"Gene expression",
"Biochemical reactions"
] |
62,141,834 | https://en.wikipedia.org/wiki/Gymnocin | Toxins | Gymnocin | [
"Environmental_science"
] | 4 | [
"Toxins",
"Toxicology"
] |
62,141,894 | https://en.wikipedia.org/wiki/Truthful%20cake-cutting | Truthful cake-cutting is the study of algorithms for fair cake-cutting that are also truthful mechanisms, i.e., they incentivize the participants to reveal their true valuations to the various parts of the cake.
The classic divide and choose procedure for cake-cutting is not truthful: if the cutter knows the chooser's preferences, they can get much more than 1/2 by acting strategically. For example, suppose the cutter values a piece by its size while the chooser values a piece by the amount of chocolate in it. So the cutter can cut the cake into two pieces with almost the same amount of chocolate, such that the smaller piece has slightly more chocolate. Then, the chooser will take the smaller piece and the cutter will win the larger piece, which may be worth much more than 1/2 (depending on how the chocolate is distributed).
Randomized mechanisms
There is a trivial randomized truthful mechanism for fair cake-cutting: select a single agent uniformly at random, and give him/her the entire cake. This mechanism is trivially truthful because it asks no questions. Moreover, it is fair in expectation: the expected value of each partner is exactly 1/n. However, the resulting allocation is not fair. The challenge is to develop truthful mechanisms that are fair ex-post and not just ex-ante. Several such mechanisms have been developed.
Exact division mechanism
An exact division (aka consensus division) is a partition of the cake into n pieces such that each agent values each piece at exactly 1/n. The existence of such a division is a corollary of the Dubins–Spanier convexity theorem. Moreover, there exists such a division with at most cuts; this is a corollary of the Stromquist–Woodall theorem and the necklace splitting theorem.
In general, an exact division cannot be found by a finite algorithm. However, it can be found in some special cases, for example when all agents have piecewise-linear valuations. Suppose we have a non-truthful algorithm (or oracle) for finding an exact division. It can be used to construct a randomized mechanism that is truthful in expectation. The randomized mechanism is a direct-revelation mechanism - it starts by asking all agents to reveal their entire value-measures:
Ask the agents to report their value measures.
Use the existing algorithm/oracle to generate an exact division.
Perform a random permutation on the consensus partition and give each partner one of the pieces.
Here, the expected value of each agent is always 1/n regardless of the reported value function. Hence, the mechanism is truthful – no agent can gain anything from lying. Moreover, a truthful partner is guaranteed a value of exactly 1/n with probability 1 (not only in expectation). Hence the partners have an incentive to reveal their true value functions.
Super-proportional mechanism
A super-proportional division is a cake-division in which each agent receives strictly more than 1/n by their own value measures. Such a division is known to exist if and only if there are at least two agents that have different valuations to at least one piece of the cake. Any deterministic mechanism that always returns a proportional division, and always returns a super-proportional division when it exists, cannot be truthful.
Mossel and Tamuz present a super-proportional randomized mechanism that is truthful in expectation:
Pick a division from a certain distribution D over divisions.
Ask each agent to evaluate his/her piece.
If all n evaluations are more than 1/n, then implement the allocation and finish.
Otherwise, use the exact-division mechanism.
The distribution D in step 1 should be chosen such that, regardless of the agents' valuations, there is a positive probability that a super-proportional division be selected if it exists. Then, in step 2 it is optimal for each agent to report the true value: reporting a lower value either has no effect or might cause the agent's value to drop from super-proportional to just proportional (in step 4); reporting a higher value either has no effect or might cause the agent's value to drop from proportional to less than 1/n (in step 3).
Approximate exact division using queries
Suppose that, rather than directly revealing their valuations, the agents reveal their values indirectly by answering mark and eval queries (as in the Robertson-Webb model).
Branzei and Miltersen show that the exact-division mechanism can be "discretized" and executed in the query model. This yields, for any , a randomized query-based protocol, that asks at most queries, is truthful in expectation, and allocates each agent a piece of value between and , by the valuations of all agents.
On the other hand, they prove that, in any deterministic truthful query-based protocol, if all agents value all parts of the cake positively, there is at least one agent who gets the empty piece. This implies that, if there are only two agents, then at least one agent is a "dictator" and gets the entire cake. Obviously, any such mechanism cannot be envy-free.
Randomized mechanism for piecewise-constant valuations
Suppose all agents have piecewise-constant valuations. This means that, for each agent, the cake is partitioned into finitely many subsets, and the agent's value density in each subset is constant. For this case, Aziz and Ye present a randomized algorithm that is more economically-efficient: Constrained Serial Dictatorship is truthful in expectation, robust proportional, and satisfies a property called unanimity: if each agent's most preferred 1/n length of the cake is disjoint from other agents, then each agent gets their most preferred 1/n length of the cake. This is a weak form of efficiency that is not satisfied by the mechanisms based on exact division. When there are only two agents, it is also polynomial-time and robust envy-free.
Deterministic mechanisms: piecewise-constant valuations
For deterministic mechanisms, the results are mostly negative, even when all agents have piecewise-constant valuations.
Kurokawa, Lai and Procaccia prove that there is no deterministic, truthful and envy-free mechanism that requires a bounded number of Robertson-Webb queries.
Aziz and Ye prove that there is no deterministic truthful mechanism that satisfies either one of the following properties:
Proportional and Pareto-optimal;
Robust-proportional and non-wasteful ("non-wasteful" means that no piece is allocated to an agent who does not want it; it is weaker than Pareto-optimality).
Menon and Larson introduce the notion of ε-truthfulness, which means that no agent gains more than a fraction ε from misreporting, where ε is a positive constant independent of the agents' valuations. They prove that no deterministic mechanism satisfies either one of the following properties:
ε-truthful, approximately-proportional and non-wasteful (for approximation constants at most 1/n);
Truthful, approximately-proportional and connected (for approximation constant at most 1/n).
They present a minor modification to the Even–Paz protocol and prove that it is ε-truthful with ε = 1 - 3/(2n) when n is even, and ε = 1 - 3/(2n) + 1/n2 when n is odd.
Bei, Chen, Huzhang, Tao and Wu prove that there is no deterministic, truthful and envy-free mechanism, even in the direct-revelation model, that satisfies either one of the following additional properties:
Connected pieces;
Non-wasteful;
Position oblivious - the allocation of a cake-part is based only on the agents' valuations of that part, and not on its relative position on the cake.
Note that these impossibility results hold with or without free disposal.
On the positive side, in a replicate economy, where each agent is replicated k times, there are envy-free mechanisms in which truth-telling is a Nash equilibrium:
With connectivity requirement, in any envy-free mechanism, truth-telling converges to a Nash equilibrium when k approaches infinity;
Without connectivity requirement, in the mechanism that allocates each homogeneous sub-interval equally among all agents, truth-telling is a Nash equilibrium already when k ≥ 2.
Tao improves the previous impossibility result by Bei, Chen, Huzhang, Tao and Wu and shows that there is no deterministic, truthful and proportional mechanism, even in the direct-revelation model, and even when all of the followings hold:
There are only two agents;
Agents are hungry: each agent's valuation is positive (i.e., cannot be 0);
The mechanism is allowed to leave some part of the cake unallocated.
It is open whether this impossibility result extends to three or more agents.
On the positive side, Tao presents two algorithms that attain a weaker notion called "proportional risk-averse truthfulness" (PRAT). It means that, in any profitable deviation for agent i, there exist valuations of the other agents, for which i gets less than his proportional share. This property is stronger than "risk-averse truthfulness", which means that, in any profitable deviation for i, there exist valuations of the other agents, for which i gets less than his value in a truthful reporting. He presents an algorithm that is PRAT and envy-free, and an algorithm that is PRAT, proportional and connected.
Piecewise-uniform valuations
Suppose all agents have piecewise-uniform valuations. This means that, for each agent, there is a subset of the cake that is desirable for the agent, and the agent's value for each piece is just the amount of desirable cake that it contains. For example, suppose some parts of the cake are covered by a uniform layer of chocolate, while other parts are not. An agent who values each piece only by the amount of chocolate it contains has a piecewise-uniform valuation. This is a special case of piecewise-constant valuations. Several truthful algorithms have been developed for this special case.
Chen, Lai, Parkes and Procaccia present a direct-revelation mechanism that is deterministic, proportional, envy-free, Pareto-optimal, and polynomial-time. It works for any number of agents. Here is an illustration of the CLPP mechanism for two agents (where the cake is an interval).
Ask each agent to report his/her desired intervals.
Each sub-interval, that is desired by no agent, is discarded.
Each sub-interval, that is desired by exactly one agent, is allocated to that agent.
The sub-intervals, that are desired by both agents, are allocated such that both agents get an equal total length.
Now, if an agent says that he wants an interval that he actually does not want, then he may get more useless cake in step 3 and less useful cake in step 4. If he says that he does not want an interval that he actually wants, then he gets less useful cake in step 3 and more useful cake in step 4, however, the amount given in step 4 is shared with the other agent, so all in all, the lying agent is at a loss. The mechanism can be generalized to any number of agents.
The CLPP mechanism relies on the free disposal assumption, i.e., the ability to discard pieces that are not desired by any agent.Note: Aziz and Ye presented two mechanisms that extend the CLPP mechanism to piecewise-constant valuations - Constrained Cake Eating Algorithm and Market Equilibrium Algorithm. However, both these extensions are no longer truthful when the valuations are not piecewise-uniform. Maya and Nisan show that the CLPP mechanism is unique in the following sense. Consider the special case of two agents with piecewise-uniform valuations, where the cake is [0,1], Alice wants only the subinterval [0,a] for some a<1, and Bob desires only the subinterval [1−b,1] for some b<1. Consider only non-wasteful mechanisms - mechanisms that allocate each piece desired by at least one player to a player who wants it. Each such mechanism must give Alice a subset [0,c] for some c<1 and Bob a subset [1−d,1] for some d<1. In this model:
A non-wasteful determininstic mechanism is truthful iff, for some parameter t in [0,1], it gives Alice the interval [0, min(a, max(1−b,t))] and Bob the interval [1−min(b,max(1−a,1−t)),1]
Such mechanism is envy-free iff t=1/2; in this case it is equivalent to the CLPP mechanism
They also show that, even for 2 agents, any truthful mechanism achieves at most 0.93 of the optimal social welfare.
Li, Zhang and Zhang show that the CLPP mechanism works well even when there are externalities (i.e., some agents derive some benefit from the value given to others), as long as the externalities are sufficiently small. On the other hand, if the externalities (either positive or negative) are large, no truthful non-wasteful and position independent mechanism exists.
Alijani, Farhadi, Ghodsi, Seddighin and Tajik present several mechanisms for special cases of piecewise-uniform valuations:
The expansion process handles piecewise-uniform valuations where each agent has a single desired interval, and moreover, the agents' desired intervals satisfy an ordering property. It is polynomial-time, truthful, envy-free, and guarantees connected pieces.
The expansion process with unlocking handles piecewise-uniform valuations where each agent has a single desired interval, but without the ordering requirement. It is polynomial-time, truthful, envy-free, and not necessarily connected, but it makes at most 2n−2 cuts.
Bei, Huzhang and Suksompong present a mechanism for two agents with piecewise-uniform valuations, that has the same properties of CLPP (truthful, deterministic, proportional, envy-free, Pareto-optimal and runs in polynomial time), but guarantees that the entire cake is allocated:
Find the smallest x in [0,1] such that Alice's desired length in [0,x] equals Bob's desired length in [x,1].
Give Alice the intervals in [0,x] valued by Alice and the intervals in [x,1] not valued by Bob; give the remainder to Bob.
The BHS mechanism works both for cake-cutting and for chore division (where the agents' valuations are negative). Note that BHS does not satisfy some natural desirable properties:
It does not guarantee connected pieces, for example when Alice wants [0,1] and Bob wants [0,0.5], then x=0.25, Alice gets [0,0.25] and [0.5,1], and Bob gets [0.25,0.5].
It is not anonymous (see symmetric fair cake-cutting): if Alice wants [0,1] and Bob wants [0,0.5], then Alice gets a desired length of 0.75 and Bob gets 0.25, but if the valuations are switched (Alice wants [0,0.5] and Bob wants [0,1]), then x=0.5 and both agents get desired length 0.5.
It is not position oblivious: if Alice wants [0,0.5] and Bob wants [0,1] then both agents get value 0.5, but if Alice's desired interval moves to [0.5,1] then x=0.75 and Alice gets 0.25 and Bob gets 0.75.
This is not a problem with the specific mechanism: it is provably impossible to have a truthful and envy-free mechanism that allocates the entire cake and guarantees any of these three properties, even for two agents with piecewise-uniform valuations.
The BHS mechanism was extended to any number of agents, but only for a special case of piecewise-uniform valuations, in which each agent desires only a single interval of the form [0, xi].
Ianovsky proves that no truthful mechanism can attain a utilitarian-optimal cake-cutting, even when all agents have piecewise-uniform valuations. Moreover, no truthful mechanism can attain an allocation with utilitarian welfare at least as large as any other mechanism. However, there is a simple truthful mechanism (denoted Lex Order) that is non-wasteful: give to agent 1 all pieces that he likes; then, give to agent 2 all pieces that he likes and were not yet given to agent 1; etc. A variant of this mechanism is the Length Game, in which the agents are renamed by the total length of their desired intervals, such that the agent with the shortest interval is called 1, the agent with the next-shortest interval is called 2, etc. This is not a truthful mechanism, however:
If all agents are truthful, then it produces a utilitarian-optimal allocation.
If the agents are strategic, then all its well-behaved Nash equilibria are Pareto-efficient and envy-free, and yield the same payoffs as the CLPP mechanism.
Summary of truthful mechanisms and impossibility results
See also
Strategic fair division
Truthful resource allocation
References
Fair division protocols
Mechanism design
Cake-cutting | Truthful cake-cutting | [
"Mathematics"
] | 3,693 | [
"Game theory",
"Mechanism design"
] |
62,142,030 | https://en.wikipedia.org/wiki/Adhesive%20remover | Adhesive remover is a substance intended to break down and remove glue and its remnants from surfaces.
Description
Adhesive removers are intended to break down glue so that it can be removed from surfaces easily. Formulations may be designed to remove a broad range of adhesives or to address a specific bond. Many general purpose removers are intended to remove residue from adhesive tape.
Formulations
Adhesive removers are often based on organic solvents, which can dissolve or soften many adhesive polymers that do not dissolve in water. They may also contain a gelling agent, increasing viscosity so that the product sticks to the area to be treated rather than running off. Common solvents used include -limonene, aliphatic alkanes, and acetone.
Heptane is also used as an adhesive remover by stamp collectors. Since 1974, the United States Postal Service has issued self-adhesive stamps that some collectors find difficult to separate from envelopes via the traditional method of soaking in water. Heptane-based products, like Bestine, as well as limonene-based products, have become popular solvents for removing stamps more easily.
References
Adhesives
Cleaning products | Adhesive remover | [
"Chemistry"
] | 248 | [
"Cleaning products",
"Products of chemical industry"
] |
62,142,085 | https://en.wikipedia.org/wiki/INCA%20%28machine%20brand%29 | INCA was a brand of woodworking machines made by Injecta AG in Teufental, Switzerland. It was active from 1921 until 2011 when it was liquidated. INCA's machines can still be found widely on the second-hand market in Europe and North America.
Overview
INCA had a relatively limited lineup of table saws, bandsaws, jointer-planers, as well as a few other types of machines. The company was known for its reliability and quality.
The thing that set them apart from most competitors was the use of cast aluminum, which also explains their name (INjected Cast Aluminium). The use of this material allowed for very precise castings of parts, while keeping the weight of the machines relatively low.
A small collection of the original inventory of the INCA factory can be found in the local museum of Aargau, Switzerland.
See also
Rema S. A.
References
External links
Wood Chipper
Swiss brands
Woodworking machines | INCA (machine brand) | [
"Physics",
"Technology"
] | 194 | [
"Physical systems",
"Machines",
"Woodworking machines"
] |
67,378,909 | https://en.wikipedia.org/wiki/NGC%201001 | NGC 1001 is an unbarred spiral galaxy in the constellation Perseus. It was discovered on December 8, 1871 by the astronomer Édouard Stephan.
See also
List of NGC objects (1001–2000)
References
Perseus (constellation)
1001
Unbarred spiral galaxies
010050
Astronomical objects discovered in 1871
Discoveries by Édouard Stephan | NGC 1001 | [
"Astronomy"
] | 71 | [
"Perseus (constellation)",
"Constellations"
] |
67,379,354 | https://en.wikipedia.org/wiki/Asterionellopsis | Asterionellopsis is a genus of diatoms belonging to the family Asterionellopsidaceae.
Species:
Asterionellopsis glacialis
Asterionellopsis guyunusae
Asterionellopsis kariana
Asterionellopsis lenisilicea
Asterionellopsis maritima
Asterionellopsis socialis
Asterionellopsis thurstonii
Asterionellopsis tropicalis
References
Diatoms
Diatom genera | Asterionellopsis | [
"Biology"
] | 98 | [
"Diatoms",
"Algae"
] |
67,379,374 | https://en.wikipedia.org/wiki/Asterionellopsidaceae | Asterionellopsidaceae is a family of diatoms belonging to the order Rhaphoneidales.
Genera:
Asterionellopsis
Asteroplanus
Bleakeleya
References
Diatoms
Diatom families | Asterionellopsidaceae | [
"Biology"
] | 48 | [
"Diatoms",
"Algae"
] |
67,379,629 | https://en.wikipedia.org/wiki/Aulacoseira | Aulacoseira is a genus of diatoms belonging to the family Aulacoseiraceae.
The genus has cosmopolitan distribution.
Species:
Aulacoseira accincta
Aulacoseira acicularia
Aulacoseira aculeifera
Aulacoseira granulata
References
Diatoms
Diatom genera | Aulacoseira | [
"Biology"
] | 66 | [
"Diatoms",
"Algae"
] |
67,380,762 | https://en.wikipedia.org/wiki/Marine%20geophysics | Marine geophysics is the scientific discipline that employs methods of geophysics to study the world's ocean basins and continental margins, particularly the solid earth beneath the ocean. It shares objectives with marine geology, which uses sedimentological, paleontological, and geochemical methods. Marine geophysical data analyses led to the theories of seafloor spreading and plate tectonics.
Methods
Marine geophysics uses techniques largely employed on the continents, from fields including exploration geophysics and seismology, and methods unique to the ocean such as sonar. Most geophysical instruments are used from surface ships but some are towed near the seafloor or function autonomously, as with Autonomous Underwater Vehicles or AUVs.
Objectives of marine geophysics include determination of the depth and features of the seafloor, the seismic structure and earthquakes in the ocean basins, the mapping of gravity and magnetic anomalies over the basins and margins, the determination of heat flow through the seafloor, and electrical properties of the ocean crust and Earth's mantle.
Navigation
Modern marine geophysics, as with most oceanographic surveying with research ships, use Global Positioning System satellites, either the U.S. GPS array or the Russian GLONASS for ship navigation. Geophysical instruments towed near the seafloor typically use acoustic transponder navigation sonar networks.
Ocean depth
The depth of the seafloor is measured using echo sounding, a sonar method developed during the 20th century and advanced during World War II. Common variations are based on the sonar beam width and number of sonar beams as is used in multibeam sonar or swath mapping that became more advanced toward the latter half of the 20th century.
Sedimentary cover of the seafloor
The thickness and type of sediments covering the ocean crust are estimated using the seismic reflection technique. This method was highly advanced by offshore oil exploration companies. The method employs a sound source at the ship with much lower frequencies than echo sounding, and an array of hydrophones towed by the ship, that record echoes from the internal structure of the sediment cover and the crust below the sediment. In some cases, reflections from the internal structure of the ocean crust can be detected. Echo sounders that use lower frequencies near 3.5 kHz are used to detect both the seafloor and shallow structure below the seafloor. Side-looking sonar, where the sonar beams are aimed just below horizontal, is used to map the seafloor bottom texture to ranges from tens of meters to a kilometer or more depending on the device.
Structure of the ocean crust and upper mantle
When the sound or energy source is separated from the recording devices by distances of several kilometers or more, then refracted seismic waves are measured. Their travel time can be used to determine the internal structure of the ocean crust, and from the seismic velocities determined by the method, an estimate can be made of the crustal rock type. Recording devices include hydrophones at the ocean surface and also ocean bottom seismographs. Refraction experiments have detected anisotropy of seismic wave speed in the oceanic upper mantle.
Measuring Earth’s magnetic and gravity fields within the ocean basins
The usual method of measuring the Earth's magnetic field at the sea surface is by towing a total field proton precession magnetometer several hundred meters behind a survey ship. In more limited surveys magnetometers have been towed at a depth close to the seafloor or attached to deep submersibles. Gravimeters using the zero-length spring technology are mounted in the most stable location on a ship; usually towards the center and low. They are specially designed to separate the acceleration of the ship from changes in the acceleration of Earth's gravity, or gravity anomalies, which are several thousand times less. In limited cases, gravity measurements have been made at the seafloor from deep submersibles.
Determine the rate of heat flow from the Earth through the seafloor
The geothermal gradient is measured using a 2-meter long temperature probe or with thermistors attached to sediment core barrels. Measured temperatures combined with the thermal conductivity of the sediment give a measure of the conductive heat flow through the seafloor.
Measure the electrical properties of the ocean crust and upper mantle
Electrical conductivity, or the converse resistivity, can be related to rock type, the presence of fluids within cracks and pores in rocks, the presence of magma, and mineral deposits like sulfides at the seafloor. Surveys can be done at either the sea surface or seafloor or in combination, using active current sources or natural Earth electrical currents, known as telluric currents.
In special cases, measurements of natural gamma radiation from seafloor mineral deposits have been made using scintillometers towed near the seafloor.
Examples of the impact of marine geophysics
Evidence for seafloor spreading and plate tectonics
Echo sounding was used to refine the limits of the known mid-ocean ridges, and to discover new ones. Further sounding mapped linear seafloor fracture zones that are nearly orthogonal to the trends of the ridges. Later, determining earthquake locations for the deep ocean discovered that quakes are restricted to the crests of the mid-ocean ridges and stretches of fracture zones that link one segment of a ridge to another. These are now known as transform faults, one of the three classes of plate boundaries. Echo sounding was used to map the deep trenches of the oceans and earthquake locations were noted to be located in and below the trenches.
Data from marine seismic refraction experiments defined a thin ocean crust, approximately 6 to 8 kilometers in thickness, divided into three layers. Seismic reflection measurements made over the ocean ridges found they are devoid of sediments at the crest, but covered by increasingly thicker sediment layers with increasing distance from the ridge crest. This observation implied that the ridge crests are younger than the ridge flanks.
Magnetic surveys discovered linear magnetic anomalies that in many areas ran parallel to an ocean ridge crest and showed a mirror-image symmetrical pattern centered on ridge crests. Correlation of the anomalies to the history of Earth's magnetic field reversals allowed the age of the seafloor to be estimated. This connection was interpreted as the spreading of the seafloor from the ridge crests. Linking spreading centers and transform faults to a common cause helped to develop the concept of plate tectonics.
When the age of the ocean crust as determined by magnetic anomalies or drill hole samples was compared to the ocean depth it was observed that depth and age are directly related in a seafloor depth age relationship. This relationship was explained by the cooling and contracting of an oceanic plate as it spreads away from a ridge crest.
Evidence for paleoclimate
Seismic reflection data combined with deep-sea drilling at some locations have identified widespread unconformities and distinctive seismic reflectors in the deep sea sedimentary record. These have been interpreted as evidence of past global climate change events. Seismic reflection surveys made on polar continental selves have identified buried sedimentary features due to the advance and retreat of continental ice sheets. Swath sonar mapping has revealed the gouge tracks of ice sheets cut as they traversed polar continental shelves in the past.
Evidence for hydrothermal vents
Heat flow measured in the ocean basins revealed that conductive heat flow decreased with the increased depth and crustal age of flanks of ocean ridges. On the ridge crest, however, conductive heat flow was found to be unexpectedly low for a location where active volcanism accompanies seafloor spreading. This anomaly was explained by the possible heat transfer by hydrothermal venting of seawater circulating in deep fissures in the crust at the ridge crest spreading centers. This hypothesis was borne out in the late 20th century when investigations by deep submersibles discovered hydrothermal vents at spreading centers.
Evidence for Mid-Ocean Ridge structure and properties
Marine gravity profiles made across Mid-Ocean Ridges showed a lack of a gravity anomaly, the Free-air anomaly is small or near zero when averaged over a broad area. This suggested that although ridges reached a height at their crest of two kilometers or more above the deep ocean basins, that extra mass was not related to an increase of gravity on the ridge of the magnitude that would be expected. The ridges are isostatically compensated, meaning the total mass below some reference depth in the mantle below the ridge is about the same everywhere. This requires a lower density mantle below the ridge crest and upper ridge flanks. Data from seismic studies revealed lower velocities under the ridges suggesting parts of the mantle below the crests are lower density rock melt. This is consistent with the theories of seafloor spreading and plate tectonics.
Centers of research conducting marine geophysics
Ocean University of China
Alfred Wegener Institute for Polar and Marine Research
Bedford Institute of Oceanography
Cambridge University
IFREMER
Lamont–Doherty Earth Observatory
National Dong Hwa University Graduate Institute of Marine Biology
National Institute of Water and Atmospheric Research
National Oceanography Centre, Southampton
Rosenstiel School of Marine, Atmospheric, and Earth Science
Scripps Institution of Oceanography
Texas A&M University
University of Hawaii (Manoa)
University of Rhode Island
University of Washington (Seattle)
Woods Hole Oceanographic Institution
See also
Project FAMOUS
RISE Project
References
Further reading
01
Hydrothermal vents
Marine geophysicists
Geophysics | Marine geophysics | [
"Physics",
"Environmental_science"
] | 1,880 | [
"Oceanography",
"Hydrology",
"Applied and interdisciplinary physics",
"Geophysics"
] |
67,380,800 | https://en.wikipedia.org/wiki/Alberto%20Kornblihtt | Alberto Kornblihtt (born June 30, 1954) is an Argentine molecular biologist who specializes in alternative ribonucleic acid splicing. During his postdoctoral training with Francisco Baralle in Oxford, Kornblihtt documented one of the first cases of alternative splicing, explaining how a single transcribed gene can generate multiple protein variants. Kornblihtt was elected as a foreign associate of the National Academy of Sciences of the United States in 2011, received the Diamond Award for the most relevant scientist of Argentina of the decade, alongside physicist Juan Martin Maldacena, in 2013, and was incorporated to the Académie des Sciences of France in 2022.
Personal life
Kornblihtt is married, with two adult sons. Outside of his research, Kornblihtt appreciates the opportunity to teach undergraduate biology students at the University of Buenos Aires. In his free time, Kornblihtt enjoys cooking, classical music, numerous genres of literature, etymology, and is a life-long lover of cinema.
Early life and education
Alberto Kornblihtt was born on June 30, 1954, in Buenos Aires, Argentina. His parents taught mathematics and geography, providing Kornblihtt and his two siblings, who also pursued careers in science and education, with an environment for knowledge and learning at an early age. When he was 16 years old, Kornblihtt enrolled in a high school botany and biology class instructed by Rosa Guaglianone, allowing Kornblihtt the opportunity to perform laboratory and microscopy work. This experience launched Kornblihtt's interest in DNA and mRNA. Following high school, Kornblihtt continued his education at the Facultad de Ciencias Exactas y Naturales (School of Sciences) of the University of Buenos Aires, earning a Biology degree in 1977. In 1980, Kornblihtt went on to earn his PhD in biochemistry from Campomar Foundation in Buenos Aires, under the mentorship of Héctor Torres. Kornblihtt then relocated to Oxford, where he held a postdoctoral position from 1981 through 1984 at the Sir William Dunn School of Pathology. Kornblihtt worked with Professor Francisco Barralle during his postdoctoral research, and together, they were successful in cloning the human fibronectin gene. They determined that fibronectin, an important glycoprotein for cell adhesion and tissue repair, was alternatively spliced and could result in the generation of twenty polypeptides.
Research
After completing his postdoctoral research in Oxford, Kornblihtt returned to Argentina in 1984 and accepted a position as an assistant professor of molecular and cell biology at Facultad de Ciencias Exactas y Naturales at the University of Buenos Aires. In 1991 he was appointed full professor and at present he is professor emeritus. Kornblihtt is also a senior CONICET investigator of the CONICET and works with a research team to study the regulation of alternative ribonucleic acid splicing. Alternative splicing occurs during gene expression, allowing exons from a gene to be excluded or included, resulting in a single gene generating multiple proteins. Major projects in Kornblihtt's lab focus on: 1) Coupling transcription with alternative splicing; 2) Alternative splicing and Chromatin; 3) Alternative splicing and spinal muscular atrophy; 4) Ultraviolet light irradiation and alternative splicing; and 5) Alternative splicing in plants.
Research on coupling transcription with alternative splicing
Kornblihtt's lab focuses on the mechanisms that couple transcription with alternative splicing for the regulation of alternative pre-mRNA splicing. Transcription is the process in which a genetic sequence of a gene is transcribed, or changed, from DNA into RNA, to allow for protein production. One of the most significant accomplishments in Kornblihtt's research came in 1997. Kornblihtt's research team was able to an alternative splicing assay combined with promoter swapping to demonstrate that transcription promoters affect the outcome of splicing They later determined that the coupling of transcription and splicing is dependent upon transcriptional elongation speed, or kinetic coupling, and the impact of transcribing RNA polymerase II on splicing. Kornblihtt's research has found that elongation affects alternative splicing events, with slow elongation increasing inclusion of approximately 80% of exons and skipping of approximately 20% in mammalian cells.
More on alternative splicing and chromatin
An additional area of Kornblihtt's study investigated the impact of chromatin structure on alternative splicing. Kornblihtt's research team demonstrated that alternative splicing is impacted by chromatin structure and the rate of transcription. They found that a tighter chromatin structure provides lower rates of elongation and looser chromatin structures provide a higher rate of elongation of transcription. These studies further contributed to the relationship between alternative splicing and epigenetics, which Kornblihtt's team used in studying potential therapies for Skeletal Muscular Atrophy.
Research on alternative splicing and spinal muscular atrophy
Spinal Muscular Atrophy (SMA) is a hereditary degenerative disease of the central nervous system resulting from a spinal motor neuron (SMN) protein shortage. This is due to the deletion or mutation of Survival of Motor Neuron 1 (SMN1). Due to the faulty SMN1 gene, SMA patients do not have enough SMN protein. SMA patients must depend on Survivor of Motor Neurons 2 (SMN2), a gene that all humans have. SMN2 cannot produce sufficient full-length protein for the motor neurons to signal muscles due to sequence differences and the exclusion of exon 7, resulting in the overall SMN protein deficiency. As a treatment strategy for SMA, the first FDA-approved drug, known as Spinraza was developed by Dr. Adrian Krainer and his Cold Spring Harbor Laboratory colleagues. Spinraza is an oligonucleotide that works to activate SMN2 to make more SMN protein in SMA patients. In 2015, the families of Spinal Muscular Atrophy patients encouraged Kornblihtt and Krainer to work together to improve the effectiveness of Spinraza or to develop alternative therapies to be used in conjunction with Spinraza. Kornblihtt's research team focuses on epigenetic strategies, a different mechanism than used Spinraza, to increase SMN protein from the SMN2 gene. Epigenetics studies changes in gene expression, without alteration to the DNA sequence. In 2017 and 2019, Kornblihtt received three separate grants from CURE SMA and FAME (Families of SMA, Argentina) to support continued work on his projects “Epigenetics in SMN2 E7 Alternative Splicing” and “Epigenetics in SMN2 E7 Alternative Splicing II”. In these projects, Kornblihtt's team has worked on the regulation of alternative pre-mRNA splicing to develop new mechanisms for SMN protein development, using a single gene to generate multiple proteins. Kornblihtt's lab continues to work on the SMN2 gene for SMA therapy that focus specifically on exon 7 inclusion to work in conjunction with oligonucleotide treatments, such as Spinraza.
Other research
UV-induced DNA damage
As a continuation of their longterm research on alternative splicing, Kornblihtt's team also studied the impact DNA damage induced by Ultraviolet light (UV) irradiation on alternative splicing in human skin cells. Their research demonstrated that the DNA-damage response to sunlight causes phosphorylation of the RNA polymerase and slowing of the enzyme. Through their research, they found that UV irradiation is necessary to trigger the alternative splicing of many genes and promoting the death of damaged or mutated cells.
Alternative splicing in plants
Adding to their research performed on human cells, Kornblihtt's team expanded their research to study transcription and alternative splicing in plants. The plant Arabidopsis thaliana was used to investigate how external lighting conditions affected alternative splicing. Research showed that the chloroplast, where photosynthesis occurs, senses light and sends a signal to the cell nucleus to regulate alternative splicing. As previously found in mammalian cells, Kornblihtt's team demonstrated that alternative splicing in plants responds to the kinetic coupling mechanism. Their research further showed that light promotes elongation in RNA polymerase II (Pol II) while elongation is lowered in darkness.
Honors and awards
In 1991, Kornblihtt received the Guggenheim Memorial Foundation Fellowship in Natural Sciences, awarded on the basis of previous achievement and basis of prior achievement and outstanding promise.
Between 2002 and 2017, Kornblihtt received the International Research Scholar of the Howard Hughes Medical Institute (HHMI) Award, given to scientists outside of the United States who have notably contributed to biological science research.
In 2003 and 2013, Kornblihtt was the recipient of the Konex Platinum Award, a cultural award given to Argentines in different fields of work.
From 2000 through 2008, Kornblihtt was awarded as a chair from the Fundacion Antorchas.
In 2010, Kornblihtt was the recipient of the Bicentennial Medal.
In 2010, Kornblihtt was elected as Investigator of the Argentine Nation Prize, granted by the President of Argentina.
From 2010 – 2011, Kornblihtt served as the President of the Argentine Society for Biochemistry and Molecular Biology (SAIB).
From 2010 – 2015, Kornblihtt served as a member of the Board of Reviewing Editors of Science.
In 2011, Kornblihtt received Honorary Mention, Domingo Faustino Sarmiento of the Argentine Senate.
In 2011, Kornblihtt was elected as a Foreign Associate of the National Academy of Sciences of the United States of America
In 2012, Kornblihtt was awarded the TWAS prize in Medical Sciences, an award given to individual scientists in developing countries for outstanding scientific contributions.
In 2012, Kornblihtt was elected foreign member of EMBO (European Molecular Biology Organization).
In 2013, Kornblihtt was a recipient of the Diamond Award for the most relevant scientist of Argentina of the decade, alongside physicist Juan Martin Maldacena.
In 2022, Kornblihtt was elected as foreign member of the Académie de Sciences of France.
Kornblihitt is a three-time recipient of the CURE SMA and FAME Grant in 2017, 2019 and 2023 for his research projects, Epigenetics in SMN2 E7 Alternative Splicing” and “Epigenetics in SMN2 E7 Alternative Splicing II”.
References
1954 births
Living people
21st-century Argentine biologists
Molecular biologists
Academic staff of the University of Buenos Aires | Alberto Kornblihtt | [
"Chemistry"
] | 2,307 | [
"Molecular biologists",
"Biochemists",
"Molecular biology"
] |
67,382,116 | https://en.wikipedia.org/wiki/4-Chloro-4-deoxygalactose | 4-Chloro-4-deoxygalactose (chlorodeoxygalactose) is chlorinated derivative of the sugar galactose. It is one of the two components comprising the disaccharide sucralose, a commercial sugar substitute. It is a hydrolysis product when sucralose is degraded.
References
Organochlorides
Monosaccharide derivatives | 4-Chloro-4-deoxygalactose | [
"Chemistry"
] | 87 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
67,383,450 | https://en.wikipedia.org/wiki/Lock%26Stock | Lock&Stock is a mobile application in the educational sector intended at helping students by discouraging the use of mobile phones during classes. They aim to reduce the use of cell phones by students and encourage their digital wellbeing by providing rewards and points when they stay off their phones. 67,500 students have currently registered for the app and the total number of time spent offline amounts to over 841 years. The application has 1,181 university partners and has dispersed over AED 3 million scholarships in 2020.
History
The Lock&Stock app was founded in 2017 and is headquartered in Dubai, UAE. Craig Fernandes, a former student at the University of Iowa in the United States founded the Lock&Stock app along with his father Ian Fernandes as co-founder and COO, and with Hussain Ali Asgar, joining as Chief Marketing Officer. It was founded to counter the menace of digital addiction, with students wasting approximately 20% of their time on mobile phones during classes. According to new research from the United Arab Emirates University, almost 30 percent of young Emiratis might be addicted to their phones.
Features
Lock&Stock is a free to use mobile app for students that allows them to earn keys each time their phones are locked. A student earns one key for every minute they are away from their phones. The longer time the student's phone is locked, the more rewards he earns. The app is programmed to only work on campuses. Students can use their rewards to get discounts from brands and to secure scholarships. Once the student leaves the marked radius, they can no longer collect rewards. Lock&Stock recently launched SecureMyScholarship, a website that allows students to secure scholarships from over 1,000 universities.
References
Mobile applications
Social media
Android (operating system) software
IOS software
Cross-platform software
Communication software | Lock&Stock | [
"Technology"
] | 373 | [
"Computing and society",
"Social media"
] |
67,383,753 | https://en.wikipedia.org/wiki/Suman%20Banerjee | Suman Banerjee is an Indian computer scientist and businessman working as the David J. DeWitt Professor of computer science at the University of Wisconsin–Madison.
Education
Banerjee earned a Bachelor of Technology degree in computer science and engineering from IIT Kanpur in 1996, followed by a Master of Science and PhD in computer science from the University of Maryland, College Park.
Career
Banerjee worked as an assistant and associate professor at the University of Wisconsin-Madison from 2004 to 2014. He was the CTO and co-founder of StratusWorX, a company that developed cloud workspace software. In July 2020, Ericsson acquired StratusWorX and the company's patent portfolio.
Banerjee was named an ACM Fellow in 2020 for his contributions to research in the area of wireless systems and an IEEE Fellow in 2022 for his contributions to the "development of tools to improve performance and usability of wireless systems". He has been cited more than 28,000 times (April 2021).
References
Living people
University System of Maryland alumni
Year of birth missing (living people) | Suman Banerjee | [
"Technology"
] | 227 | [
"Computing stubs",
"Computer specialist stubs"
] |
67,383,916 | https://en.wikipedia.org/wiki/Pisanie | A pisanie is an architectural element, that consists of an inscription carved in stone, wood, metal, painted, etc., on the top of tombs or above the main door at the entrance in a church, in which are recorded information about the church, the donor, the founder, the builder, the data when the church was built, etc. The inscription usually includes a religious invocation, the name of the founder or founders, the date of construction, the motivation of the building, the circumstances of the time and other data.
The term comes from the Church Slavonic language and many churches and monasteries have the inscription written using the Cyrillic script.
Gallery
Notes
External links
Architectural elements | Pisanie | [
"Technology",
"Engineering"
] | 140 | [
"Building engineering",
"Architectural elements",
"Components",
"Architecture"
] |
67,384,638 | https://en.wikipedia.org/wiki/List%20of%20investigational%20hallucinogens%20and%20entactogens | This is a list of investigational hallucinogens and entactogens, or hallucinogens and entactogens that are currently under formal development for clinical use but are not yet approved.
Chemical/generic names are listed first, with developmental code names, synonyms, and brand names in parentheses. The list also includes non-hallucinogenic drugs related to hallucinogens, such as non-hallucinogenic serotonin 5-HT2A receptor agonists and non-hallucinogenic ketamine analogues. Cannabinoids, or cannabinoid receptor modulators, are not included in this list. Many of the indications are not for continuous medication therapy but rather are for medication-assisted psychotherapy or short-term use only.
This list was last comprehensively updated in October 2024. It is likely to become outdated with time.
Under development
Preregistration
Midomafetamine (MDMA; "ecstasy") – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – post-traumatic stress disorder, alcoholism, social anxiety in autism – Multidisciplinary Association for Psychedelic Studies (MAPS), Lykos Therapeutics
Phase 3
CYB003 (CYB-003; deuterated psilocybin analogue; deuterated psilocin) – serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – major depressive disorder, alcoholism, psychiatric disorders – Cybin
Ketamine (HTX-100; NRX-100) – ionotropic glutamate NMDA receptor antagonist – suicidal ideation, mental disorders – NRx Pharmaceuticals
Psilocybin (COMP-360; COMP360) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders, anorexia nervosa, bipolar depression, major depressive disorder, post-traumatic stress disorder, somatoform disorders, pervasive child development disorders – COMPASS Pathways
Phase 2
Arketamine ((R)-ketamine; PCN-101) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders – ATAI Life Sciences
CYB004 (CYB-004; deuterated dimethyltryptamine; deuterated DMT; dDMT) – non-selective serotonin receptor agonist and psychedelic hallucinogen – Cybin
Dimethyltryptamine (DMT; BMND-01, BMND-02, BMND-03) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders, fibromyalgia, substance-related disorders – Biomind Labs
Esketamine (CLE-100) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Clexio Biosciences
GM-2505 – serotonin 5-HT2A and 5-HT2C receptor agonist, psychedelic hallucinogen, and serotonin releasing agent – major depressive disorder – Gilgamesh Pharmaceuticals
Ketamine (Ereska; IN ketamine; ketamine IN; intranasal ketamine; intranasal racemic ketamine; PMI-100, PMI-150, SLS-002, TUR-002) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – post-traumatic stress disorder, suicidal ideation, acute pain, cancer pain – Seelos Therapeutics
Ketamine (AWKN-001, AWKN-P-001) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – alcoholism, binge-eating disorder, gambling, impulse control disorders, obsessive–compulsive disorder – Awakn Life Sciences
Ketamine extended-release (R-107, R107) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Douglas Pharmaceuticals
Ketamine prolonged-release oral (KET-01) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders, neuropathic pain – Ketabon
Lysergic acid diethylamide (LSD; lysergide; MM-120) – non-selective serotonin receptor agonist and psychedelic hallucinogen – anxiety disorders, attention-deficit hyperactivity disorder, cluster headache, major depressive disorder, pain – MindMed
Lysergic acid diethylamide (LSD; lysergide; MB-22001) – non-selective serotonin receptor agonist and psychedelic hallucinogen – major depressive disorder – MindBio Therapeutics
Mebufotenin (5-MeO-DMT; BPL-002, BPL-003) – non-selective serotonin receptor agonist and psychedelic hallucinogen – alcoholism, major depressive disorder – Beckley Psytech
Mebufotenin (5-MeO-DMT; BMND-05, BMND-08) – non-selective serotonin receptor agonist and psychedelic hallucinogen – Alzheimer's disease, pain – Biomind Labs
Mebufotenin (5-MeO-DMT; GH001, GH-001) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders – GH Research
Methylone (MDMC; TSND-201) – serotonin, norepinephrine, and dopamine releasing agent and entactogen – post-traumatic stress disorders – Transcend Therapeutics
Midomafetamine (MDMA; "ecstasy") – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – alcoholism – Awakn Life Sciences
MSP-1014 (psilocin prodrug) – non-selective serotonin receptor agonist and psychedelic hallucinogen – major depressive disorder – Mindset Pharma, Otsuka America Pharmaceutical
OSU-6162 (PNU-9639; PNU-96391; PNU-96391A) – non-hallucinogenic serotonin 5-HT2A receptor partial agonist, dopamine D2 receptor partial agonist, and sigma σ1 receptor ligand (so-called "monoaminergic stabilizer") – bipolar depression, chronic fatigue syndrome, depressive disorders, stroke, subarachnoid hemorrhage, Parkinson's disease – Carlsson Research AB, Pfizer
Psilocybin (CYB-001; INT0052/2020) – non-selective serotonin receptor agonist and psychedelic hallucinogen – mental disorders, major depressive disorder, anxiety disorders – Cybin
Psilocybin (MYCO-001, MYCO-003) – non-selective serotonin receptor agonist and psychedelic hallucinogen – post-traumatic stress disorder, anxiety disorders, depressive disorders, headache, substance-related disorders – Mydecine
Psilocybin (PEX-010) – non-selective serotonin receptor agonist and psychedelic hallucinogen – adjustment disorders, alcoholism, depressive disorders, anxiety disorders – Filament Health
Psilocybin (PFN™; TRP-8802, TRP-8803, TRP-8804, TRYP-0082) – non-selective serotonin receptor agonist and psychedelic hallucinogen – binge-eating disorder, fibromyalgia, irritable bowel syndrome, cancer, complex regional pain syndrome, pain – Tryp Therapeutics
Psilocybin (SYNP-101; synthetic psilocybin) – alcoholism, obsessive–compulsive disorders, cluster headache, migraine – Ceruvia Lifesciences
RE-104 (FT-104; 4-HO-DiPT/iprocin prodrug) – serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – postnatal depression – Reunion Neuroscience
Xenon (NBTX-001) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – post-traumatic stress disorder, Alzheimer's disease, irritable bowel syndrome, Parkinson's disease, pervasive child development disorders, panic disorder – Nobilis Therapeutics
Zolunicant (18-methoxycoronaridine; 18-MC; MM-110) – α3β4 nicotinic acetylcholine receptor antagonist, other actions – leishmaniasis, opioid-related disorders, substance-related disorders – MindMed
Phase 1/2
Dimethyltryptamine (DMT; SPL-026) – non-selective serotonin receptor agonist and psychedelic hallucinogen – major depressive disorder – Small Pharma, Cybin
Ibogaine – various actions and hallucinogen – opioid-related disorders – ATAI Life Sciences/DemeRx
Psilocybin (PSY-0.1, PSY-0.2, PSY-0.3, PSY-0.4/0.5, PSY-0.6) – non-selective serotonin receptor agonist and psychedelic hallucinogen – substance-related disorders, neurological disorders, opioid-related disorders, psychiatric disorders, traumatic brain injury, cancer, anxiety disorders, bipolar disorders, depressive disorders, eating disorders, and additional unspecified conditions – Revive Therapeutics
Psilocybin infusion (ELE-101, ELE-Psilo, ELE-Psilo+) – non-selective serotonin receptor agonist and psychedelic hallucinogen – major depressive disorder – Eleusis, Beckley Psytech
Phase 1
(R)-Midomafetamine ((R)-MDMA; (R)-methylenedioxymetamfetamine; MM-402) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – pervasive child development disorders – MindMed
(R)-Midomafetamine ((R)-MDMA; R-MDMA; EMP-01) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – post-traumatic stress disorder, social phobia – EmpathBio
Dimethyltryptamine (DMT; VLS-01) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders – ATAI Life Sciences, Viridia Life Sciences
Dimethyltryptamine (DMT; EBRX-101) – non-selective serotonin receptor agonist and psychedelic hallucinogen – smoking withdrawal, alcoholism – Entheon Biomedical
DLX-001 (DLX-1; AAZ; AAZ-A-154) – non-hallucinogenic serotonin 5-HT2A receptor agonist – CNS disorders, major depressive disorder – Delix Therapeutics
Esketamine ((S)-ketamine; S-ketamine; AWKN-002) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – alcoholism – Awakn Life Sciences
Ketamine oral (Keticap) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – mood disorders – Neurocentrx Pharma
Ketanserin – serotonin 5-HT2A and α1-adrenergic receptor antagonist – hallucinogen antidote – MindMed
Lys-MDA – methylenedioxyamphetamine (MDA) prodrug (serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen) – unknown – MindMed, MiHKAL
Lys-MDMA – midomafetamine (MDMA) prodrug (serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen) – unknown – MindMed, MiHKAL
Mescaline (BMND-06, BMND-09) – non-selective serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – obesity, Parkinson's disease, inflammation – Biomind Labs
Psilocybin (MLS-101) – non-selective serotonin receptor agonist and psychedelic hallucinogen – psychiatric disorders – MycoMedia Life Sciences
Preclinical
2-Bromo-LSD (bromolysergide; BOL-148; NYPRG-101) – non-hallucinogenic serotonin 5-HT2A receptor agonist and other actions – cluster headache, migraine – Ceruvia Lifesciences
2-Bromo-LSD (bromolysergide; BOL-148; BETR-001, TD-0148A) – non-hallucinogenic serotonin 5-HT2A receptor agonist and other actions – cluster headache, major depressive disorder, neuropathic pain, post-traumatic stress disorders – Transcend Biodynamics, BetterLife Pharma
2-Fluorodeschloroketamine (2-FDCK) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Clearmind Medicine
3-Methylmethcathinone (3-MMC; metaphedrone) – serotonin, norepinephrine, and dopamine releasing agent and entactogen – dyskinesias – Clearmind Medicine
5-Methoxy-2-aminoindane (5-MeO-AI; MEAI; CMND-100) – serotonin releasing agent and entactogen – alcoholism, cocaine use disorder, metabolic syndrome, obesity – Clearmind Medicine
5-MeO-MiPT (MSD-001; "moxy") – non-selective serotonin receptor agonist and psychedelic hallucinogen – undefined indication – Mindstate Design Labs
AKO-001 – serotonin 5-HT2 receptor agonist – stroke – Akome Biotech
AKO-002 (psilocybin-based formulation) – non-selective serotonin receptor agonist and psychedelic hallucinogen – Alzheimer's disease – Akome Biotech
AKO-003 (ketamine-based psychedelic formulation) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Akome Biotech
AKO-004 – serotonin 5-HT2 receptor agonist and psychedelic hallucinogen – Parkinson's disease – Akome Biotech
BMB-201 (BMB-A39a prodrug) – non-hallucinogenic serotonin 5-HT2A and 5-HT2C receptor agonist and psychoplastogen – generalized anxiety disorder, pain – Bright Minds Biosciences
BMB-202 – selective serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – depressive disorders, post-traumatic stress disorder – Bright Minds Biosciences
Dimethyltryptamine (DMT) – non-selective serotonin receptor agonist and psychedelic hallucinogen – psychiatric disorders, social phobia – Psilera
EB-002 (EB-373; psilocin prodrug) – non-selective serotonin receptor agonist and psychedelic hallucinogen – anxiety disorders – Enveric Biosciences
EGX-A – serotonin 5-HT2A receptor agonist – depressive disorders – ATAI Life Sciences
EGX-B – serotonin 5-HT2A receptor agonist – depressive disorders – ATAI Life Sciences
ENX-105 – dopamine D2 and D3 receptor antagonist and non-hallucinogenic serotonin 5-HT1A and 5-HT2A receptor agonist – mood disorders, post-traumatic stress disorder – Engrail Therapeutics
GM-3009 (ibogaine analogue) – various actions – opioid-related disorders – Gilgamesh Pharmaceuticals
Ibogaine – various actions and hallucinogen – CNS disorders, neuropathic pain, traumatic brain injury – MINDCURE
Ibogaine derivatives - Terran Biosciences – various actions and potential hallucinogens – neurological disorders, psychiatric disorders – Terran Biosciences
ITI-1549 – non-hallucinogenic serotonin 5-HT2A receptor agonist and serotonin 5-HT2B receptor antagonist – psychiatric disorders – Intra-Cellular Therapies
Ketamine depot (ALA-3000) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders – Alar Pharmaceuticals
Ketamine subcutaneous (BB-106) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – acute pain, mental disorders – Bexson Biomedical
Ketamine analogue (Ketamir, Ketamir-2) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders – MIRA Pharmaceuticals
Long-acting MDMA prodrug (long-acting midomafetamine prodrug) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – neurological disorders, psychiatric disorders – Terran Biosciences
LPH-5 – selective serotonin 5-HT2A receptor partial agonist and psychedelic hallucinogen – major depressive disorder – Lophora, Beckley Psytech
LPH-48 (shorter-acting LPH-5 analogue) – undefined mechanism of action and serotonergic hallucinogen – alcoholism – Lophora
Lucid-PSYCH (Lucid-201) – undefined mechanism of action and psychedelic hallucinogen – major depressive disorder – Lucid Psycheceuticals
Lysergic acid diethylamide (LSD; lysergide) – non-selective serotonin receptor agonist and psychedelic hallucinogen – neurological disorders, psychiatric disorders – Delix Therapeutics
MBDB – serotonin and norepinephrine releasing agent, weak serotonin 5-HT1 and 5-HT2 receptor ligand, and entactogen – autism – PharmAla Biotech
Mebufotenin (5-MeO-DMT; LSR-1019) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders, psychiatric disorders – Lusaris Therapeutics
Mescaline (JOUR-5700) – non-selective serotonin receptor agonist and psychedelic hallucinogen – alcoholism – Journey Colab
Midomafetamine microneedle transdermal patch (MDMA; "ecstasy") – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – anxiety disorders, depressive disorders, post-traumatic stress disorder, substance-related disorders – PharmaTher, Revive Therapeutics
MSP-4019 – undefined mechanism of action (5-MeO-DMT- and DMT-inspired drug) – neurological disorders, psychiatric disorders – Mindset Pharma, Otsuka America Pharmaceutical
MSP-4020 – undefined mechanism of action (5-MeO-DMT- and DMT-inspired drug) – neurological disorders, psychiatric disorders – Mindset Pharma, Otsuka America Pharmaceutical
MYCO-006 – undefined mechanism of action and short-acting MDMA-like entactogen – anxiety disorders – Mydecine
MYCO-007 – undefined mechanism of action and short-acting MDMA-like entactogen – undefined indication – Mydecine
Norbaeocystin – non-hallucinogenic serotonin 5-HT2A receptor agonist and other actions – mental disorders – PsyBio Therapeutics
PSIL-001 (DMT analogue) – non-hallucinogenic serotonin 5-HT1 receptor modulator – depressive disorders, mood disorders, neurodegenerative disorders, substance-related disorders – Psilera
PSIL-002 (DMT analogue) – non-hallucinogenic serotonin 5-HT1 receptor modulator – depressive disorders, mood disorders, neurodegenerative disorders, substance-related disorders – Psilera
Psilacetin (O-acetylpsilocin; 4-AcO-DMT) – non-selective serotonin receptor agonist and psychedelic hallucinogen – substance-related disorders – Psilera
Psilocin (PLZ-1015) – non-selective serotonin receptor agonist and psychedelic hallucinogen – pervasive child development disorders – Pilz Bioscience
PSYLO-1001 (Psylo-1001; PSYLO-100X) – non-hallucinogenic serotonin 5-HT2A and 5-HT6 receptor modulator – mental disorders – Psylo
PSYLO-3001 (Psylo-3001) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders, generalized anxiety disorder, social phobia – Psylo
PSYLO-4001 (Psylo-4001) – serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – depressive disorders, major depressive disorder – Psylo
Research programme: hydroxynorketamine derivatives - Spirify Pharma – amino acid modulators and serine protease modulators – depressive disorders, pain – Spirify Pharma
Research programme: Ibogaine analogues - Gilgamesh Pharmaceuticals (GM-300X) – various actions – opioid-related disorders – Gilgamesh Pharmaceuticals
Research programme: mental disorder therapeutics - Cybin (Deuterated DMT series - Cybin) – serotonin receptor modulators and psychedelic hallucinogens – mental disorders – Small Pharma, Cybin
Research programme: micro-dose serotonergics - Gilgamesh Pharmaceuticals – serotonin receptor agonists – attention-deficit hyperactivity disorder, major depressive disorder – Gilgamesh Pharmaceuticals
Research programme: non-hallucinogenic psychedelic therapeutics - Intra-Cellular Therapies (ITI-1500) – undefined mechanism of action – psychiatric disorders – Intra-Cellular Therapies
Research programme: psilocin derivatives - Enveric Biosciences – serotonin 5-HT2A receptor agonists and potential psychedelic hallucinogens – mental disorders – Enveric Biosciences
Research programme: psilocin prodrugs and derivatives - Terran Biosciences – serotonin 5-HT2A receptor agonists and psychedelic hallucinogens – neurological disorders, psychiatric disorders – Terran Biosciences
Research programme: psychedelic and empathogenic compounds - Terran Biosciences – serotonin receptor modulators – neurological disorders, psychiatric disorders – Terran Biosciences
Research programme: psychedelic-based neurological therapeutics - Psilera – undefined mechanism and psychedelic hallucinogens – alcoholism, anxiety disorders, depressive disorders, neurodegenerative disorders – Psilera
Research programme: psychedelic-based therapeutics - Clearmind Medicine/SciSparc – undefined mechanism of action – metabolic disorders, obesity, psychiatric disorders – Clearmind Medicine, SciSparc
Research programme: psychedelic microneedle patch - PharmaTher – undefined mechanism of action – neurological disorders, neuromuscular disorders, pain, psychiatric disorders – PharmaTher
Research programme: psychoplastogen therapeutics - Collaborations Pharmaceuticals – undefined mechanism of action – opioid-related disorders – Collaborations Pharmaceuticals
Research programme: serotonin 2A receptor agonists - Bright Minds Biosciences – serotonin 5-HT2A receptor agonists – major depressive disorder, post-traumatic stress disorder – Bright Minds Biosciences
Research programme: serotonin 2A/C receptor agonists - Bright Minds Biosciences – serotonin 5-HT2A and 5-HT2C receptor agonists – pain – Bright Minds Biosciences
Research programme: small tryptamine derivatives - Marvel Biosciences (non-hallucinogenic neuroplasticity program - Marvel Biosciences) – adenosine A2A receptor antagonists – depressive disorders – Marvel Biosciences
Research programme: SPL 029 series - Cybin (Oral DMT series - Cybin; SPL029) – non-selective serotonin receptor agonist and psychedelic hallucinogen – mental disorders – Small Pharma, Cybin
Serotonin 5-HT2 receptor agonists - Cybin – serotonin 5-HT2 receptor agonists (phenethylamines) – neurological disorders, psychiatric disorders – Cybin
Tabernanthalog (TBG; DLX-007; DLX-7) – non-hallucinogenic serotonin 5-HT2A receptor agonist – CNS disorders – Delix Therapeutics
Triptax – undefined mechanism of action – depressive disorders – Biomind Labs
Research
Baeocystin (PLZ-1019) – non-hallucinogenic serotonin 5-HT2A receptor agonist and other actions – pervasive developmental disorders in children – Pilz Bioscience
CYB005 (CYB-005; deuterated phenethylamine derivative) – undefined mechanism of action ("non-hallucinogenic doses") – psychiatric disorders – Cybin
Ibogaine – various actions – anorexia nervosa, neurological disorders, substance-related disorders – Biomind Labs
LSR-3000 – undefined mechanism of action (tryptamine serotonergic neuroplastogen) – neurological disorders – Lusaris Therapeutics
Lysergic acid diethylamide (LSD; lysergide; LSD-CUREfilm) – non-selective serotonin receptor agonist and psychedelic hallucinogen – mental disorders – CURE Pharmaceutical
Mebufotenin (5-MeO-DMT; LSR-2000) – non-selective serotonin receptor agonist and psychedelic hallucinogen – alcoholism, major depressive disorder – Lusaris Therapeutics
Mescaline (BMND-04) – non-selective serotonin receptor agonist and psychedelic hallucinogen – eating disorders, neurological disorders – Biomind Labs
Midomafetamine (MDMA; "ecstasy"; MDMA-CUREfilm) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – mental disorders – CURE Pharmaceutical
MYCO-002 – undefined mechanism of action and MDMA-like entactogen – mental disorders – Mydecine
MYCO-004 (patch-delivered tryptamine compound) – undefined mechanism of action and psychedelic hallucinogen – smoking withdrawal, substance-related disorders – Mydecine
MYCO-005 (psilocin analogue) – serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – anxiety disorders, depressive disorders – Mydecine
N-Methyltryptamine (NMT; monomethyltryptamine) – undefined mechanism of action and psychedelic hallucinogen – unspecified – Core One Labs
Noribogaine derived therapeutic – various actions – opioid-related disorders – Mindmed, Nextage Therapeutics
Norpsilocin (PLZ-1017) – non-hallucinogenic serotonin 5-HT2A receptor agonist and other actions – pervasive developmental disorders in children – Pilz Bioscience
Psilocybin – non-selective serotonin receptor agonist and psychedelic hallucinogen – cancer – Dominari Holdings
PSYLO-5001 (Psylo-5001) – serotonin 5-HT2A receptor agonist and psychedelic hallucinogen – mental disorders – Psylo
Research programme: 3,4-Methylenedioxymetamfetamine derivatives - Enveric Biosciences – serotonin, norepinephrine, and/or dopamine releasing agents and entactogens – mental disorders, neurological disorders, psychotic disorders – MagicMed Industries, Enveric Biosciences
Research programme: Ibogaine derivatives - MindMed/Nextage Therapeutics – various actions and potential hallucinogens – opioid-related disorders – Mindmed, Nextage Therapeutics
Research programme: lysergic acid diethylamide derivatives - Enveric Biosciences – serotonin 5-HT2A receptor agonists – mental disorders, neurological disorders, psychotic disorders – MagicMed Industries, Enveric Biosciences
Research programme: mescaline derivatives - Enveric Biosciences – serotonin 5-HT2 receptor agonists – mental disorders, neurological disorders – MagicMed Industries, Enveric Biosciences
Research programme: non-hallucinogenic psychedelic therapeutics - Sintalica Bioscience/University of Messina – undefined mechanism of action and non-hallucinogenic tryptamine serotonergic agents – Sintalica Bioscience, University of Messina
Research programme: psychiatric disorder therapies (neuroplastogens) - AbbVie/Gilgamesh Pharmaceuticals – undefined mechanism of action – psychiatric disorders – AbbVie, Gilgamesh Pharmaceuticals
Research programme: non-hallucinogenic psychiatric therapies - Daiichi Sankyo/Psylo – undefined mechanism of action – mental disorders – Daiichi Sankyo, Psylo
Research programme: non-tryptamine psychedelic small molecules - Otsuka America Pharmaceutical – serotonin receptor modulators – neurological disorders, psychiatric disorders – Mindset Pharma, Otsuka America Pharmaceutical
Research programme: psychedelic and empathogenic therapeutics - COMPASS Pathways – undefined mechanism of action – mental disorders – COMPASS Pathways, MiHKAL
Research programme: psychedelic and empathogenic compounds subcutaneous - Bexson Biomedical – undefined mechanism of action – depressive disorders, mental disorders, pain, post-traumatic stress disorder, substance-related disorders – Bexson Biomedical
Research programme: psychedelic therapeutics - COMPASS Discovery Center – serotonin 5-HT2A receptor modulators – mental disorders – COMPASS Discovery Center, COMPASS Pathways
Research programme: tryptamine analog therapeutics - Diamond Therapeutics – serotonin receptor modulators – Diamond Therapeutics
Phase unknown
Ketamine intravenous/oral (Braxia) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders – Braxia Scientific
Psilocybin (REL-P11) – non-selective serotonin receptor agonist and psychedelic hallucinogen – neurodegenerative disorders, metabolic disorders, psychiatric disorders – Arbormentis, Relmada Therapeutics
Not under development
Development suspended
Esketamine ((S)-ketamine; AM-101; esketamine otic gel; Keyzilen) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – tinnitus – Altamira Therapeutics
No development reported
Arketamine ((R)-ketamine; HR-071603; (R)-ketamine nasal spray) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – depressive disorders – Jiangsu Hengrui Medicine
Esketamine ((S)-ketamine; esketamine DPI; Falkieri; PG061) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – bipolar depression, depressive disorders – Celon Pharma
Esketamine ((S)-ketamine; IPX-237, IPX237-C0001, IPX237-C0002, IPX237-L0001) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – unspecified – IMPAX Laboratories, Amneal Laboratories
Hydroxynorketamine ((2R,6R)-hydroxynorketamine; 6-HNK; SPL-801-B) – unknown mechanism of action (non-hallucinogenic ketamine derivative and metabolite) – depressive disorders – Small Pharma, Cybin
Ketamine (ELE-Ket+) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Beckley Psytech
Ketamine intranasal – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – cluster headaches – CCH Pharmaceuticals
Ketamine sublingual (ketamine wafer; SLS-003; Wafermine) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – acute pain, dental pain, pain, depressive disorders – iX Biopharma
Ketamine transdermal patch (SHX-001) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Shenox Pharmaceuticals
Midomafetamine (MDMA; "ecstasy") – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – mood disorders, substance-related disorders – MindMed
Psilocybin (biosynthetic psilocybin; PB-1818) – non-selective serotonin receptor agonist and psychedelic hallucinogen – depressive disorders – PsyBio Therapeutics
Psilocybin (low-dose psilocybin; BPL-PSILO) – non-selective serotonin receptor agonist and psychedelic hallucinogen – headache – Beckley Psytech
Research programme: ketamine derivatives - Shenox Pharmaceuticals (SHX-004; SHX-004/005/006/007/011; SHX-005; SHX-006; SHX-007; SHX-011) – ionotropic glutamate NMDA receptor antagonists and dissociative hallucinogens – major depressive disorder, neuropathic pain – Shenox Pharmaceuticals
Research programme: serotonin psychedelics - Mydecine Innovations Group – serotonin modulators and psychedelic hallucinogens – mental disorders – Mydecine
Research programme: tryptamine based therapeutics - PsyBio Therapeutics – serotonin 5-HT2A receptor agonists – anxiety disorders, depressive disorders, post-traumatic stress disorder, substance-related disorders – PsyBio Therapeutics
XW-10508 (oral esketamine conjugate prodrug) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder, pain – XWPharma
Development discontinued
Ketamine (Ketals) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – amyotrophic lateral sclerosis, anaesthesia, drug-induced dyskinesia, Rett syndrome – PharmaTher
Ketamine intranasal – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – autistic disorder – Roivant Sciences
Research programme: ketamine deuterated - Teva Pharmaceutical Industries – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – pain – Teva Pharmaceutical Industries
Salvinorin A (INT0054/2020; RLS-01) – κ-opioid receptor agonist – depressive disorders, unspecified – Revixia Life Sciences IntelGenx Corp
20th century (1940s–1980s)
(R)-Ariadne (BL-3912A; Dimoxamine) – non-hallucinogenic serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist – depression – Bristol-Myers Company
Dimethoxybromoamphetamine (DOB; brolamfetamine) – serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist and psychedelic hallucinogen – unknown – unknown
Lysergic acid diethylamide (LSD; LSD-25; lysergide; Delysid) – non-selective serotonin receptor agonist and psychedelic hallucinogen – various uses – Sandoz
Methylenedioxyamphetamine (MDA; tenamfetamine) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptor agonist, entactogen, and weak psychedelic hallucinogen – unknown – unknown
Psilocybin (Indocybin) – non-selective serotonin receptor agonist and psychedelic hallucinogen – various uses – Sandoz
Formal development never or not yet started
Nitrous oxide (N2O; "laughing gas") – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – being studied for depression but doesn't seem to be being formally developed towards approval
Clinically used drugs
Approved drugs
Bupropion/dextromethorphan (DXM/BUP; Auvelity) – sigma σ1 receptor agonist, serotonin reuptake inhibitor, norepinephrine and dopamine reuptake inhibitor, nicotinic acetylcholine receptor negative allosteric modulator, ionotropic glutamate NMDA receptor antagonist, other actions, CYP2D6 inhibitor, and dissociative hallucinogen combination – major depressive disorder – Axsome Therapeutics
Esketamine ((S)-ketamine; Spravato) – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder – Johnson & Johnson
Off-label drugs
Ketamine – ionotropic glutamate NMDA receptor antagonist and dissociative hallucinogen – major depressive disorder, other depressive disorders, and other conditions
Discontinued drugs
Tabernanthe spp. extracts (containing ibogaine) (Lambarène, Iperton) – various actions and stimulant – fatigue, asthenia, depression, illness recovery
See also
Psychedelic treatments for trauma-related disorders
List of investigational drugs
Ketamine-assisted psychotherapy
References
External links
AdisInsight - Springer
Psychedelics Drug Development Tracker - Psychedelic Alpha
Psychedelic Drug Development Tracker Bullseye (February 2024) - Psychedelic Alpha
Drug-related lists
Dynamic lists
Experimental entactogens
Experimental hallucinogens
Psychedelic drug research | List of investigational hallucinogens and entactogens | [
"Chemistry"
] | 8,864 | [
"Drug-related lists"
] |
67,384,780 | https://en.wikipedia.org/wiki/WooYun | The WooYun () was a Mainland China-based vulnerability disclosure platform founded in May 2010 by Fang Xiaodun and Meng De. It posted an announcement on July 20, 2016 that the site was down for an upgrade and would be restored in the shortest possible time. However, as of April 12, 2021, the website remains inaccessible.
WooYun touted itself as a "free and equal platform for reporting vulnerabilities". The Wooyun.org domain name was registered on May 6, 2010.
Legal incidents
JD and Jia Wei
Jiayuan and Yuan Wei
A white hat by the name of Yuan Wei ("YW") submitted an SQL vulnerability to Jiayuan.com in December 2015. Jiayuan fixed the issue and publicly thanked YW, but reported him for alleged theft of more than 900 rows of personal information in January 2016. The suspect was taken into custody in April while maintaining his innocence, explaining the access as caused by the sqlmap program.
Shutdown
On the evening of July 19, 2016, someone broke the news that all the senior managements of WooYun were taken away by the police.
The Wall Street Journal said it was unclear whether the Chinese government shut it down or its organizers did.
iThome.com.tw speculated that the most likely reason for the shutdown of WooYun was that hackers on the platform exposed a vulnerability in the system of China's United Front Work Department, which had leaked Chinese state secrets and stepped on the bottom line of the Chinese government.
Notable disclosures
References
See also
Bug bounty program
White hat (computer security)
Defunct websites
Internet censorship
Internet properties established in 2010
Internet properties disestablished in 2016
Computer security exploits
Computing websites | WooYun | [
"Technology"
] | 349 | [
"Computing websites",
"Computer security exploits"
] |
67,385,305 | https://en.wikipedia.org/wiki/David%20Knowles%20%28engineer%29 | Professor David Knowles FREng FIMMM (born 6 January 1967) is Professor of Nuclear Engineering at the University of Bristol and Chief Executive of the UK's Henry Royce Institute for advanced materials research. From 2016 to 2019, he was the co-director of the South West Nuclear Hub, and Atkins Fellow. His work focusses primarily on understanding and modelling the degradation mechanisms in metallic materials and their interrelation with the structural integrity of rotating and static equipment in the energy sector.
Education
Knowles was educated at Toller Porcorum primary school, Beaminster School and St Catharine's College, Cambridge, graduating from the university in 1988, with triple first class honours in natural sciences (taking Materials Science and Metallurgy in Part II). He then went on to complete a PhD in 1991 - on the topic of the fatigue and fracture behaviour of aluminium-lithium based composites - under the supervision of Dr Julia King (now Baroness Brown of Cambridge).
Career
Knowles began his career in 1991 with a research fellowship at St Catharine's College, Cambridge, before moving to New Zealand to work as a research and consultancy metallurgist for Industrial Research Ltd between 1993 and 1995. He then returned to the University of Cambridge in 1995 to take up a post as lecturer in Mechanical Properties of Materials, and was also appointed assistant director of Research of the Rolls-Royce University Technology Centre. His research at that time focussed on fatigue and creep in nickel based superalloys including high stress 'low' temperature creep anisotropy in single crystals. In 2001 Knowles returned to New Zealand to take up the role of CTO at MPT Solutions, where he continued to publish academic papers with a developing interest in crystal plasticity. In 2006 he was appointed Global Research Leader for Materials at Shell Global Solutions, based in Amsterdam looking into materials for LNG and gas to liquid technologies. In 2010, he moved to Atkins as their materials authority in the energy sector, focussing on offshore wind turbine foundations and nuclear Advanced Gas Reactors. In 2016 he took up a post at the University of Bristol as Professor of Nuclear Engineering, and co-director of the South West Nuclear Hub.
Knowles was named Chief Executive of the Henry Royce Institute for advanced materials research in 2019. He has continued his research as the principal investigator on the 'Sindri' prosperity partnership EPSRC project, working with a number of university partners alongside EDF and UKAEA, which is focussed on characterising and modelling the meso to macro scale mechanics of alloys. In particular, he is interested in researching the use of data-centric methods to interrogate and describe material mechanical behaviour which can then be used to predict the condition of components of nuclear power plants.
Awards and recognition
Knowles was awarded a Fellowship of the Institute of Materials, Minerals and Mining (FIMMM) in 2004 in recognition of his contributions to the field of materials science. In 2015, he was also made Fellow of the Royal Academy of Engineering (FREng). He holds two European patents and has authored over 100 academic papers - five of which have been cited over 100 times - and he has also given a number of invited lectures and conference keynotes
References
1967 births
Living people
Royal Academy of Engineering
Materials scientists and engineers
Metallurgists
Fracture mechanics
Fellows of the Royal Academy of Engineering
Fellows of the Institute of Materials, Minerals and Mining | David Knowles (engineer) | [
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"Materials_science",
"Engineering"
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"Structural engineering",
"Fracture mechanics",
"Metallurgy",
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"Materials scientists and engineers",
"National academies of engineering",
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67,385,737 | https://en.wikipedia.org/wiki/Discharge%20of%20radioactive%20water%20of%20the%20Fukushima%20Daiichi%20Nuclear%20Power%20Plant | Radioactive water from the Fukushima Daiichi Nuclear Power Plant in Japan began being discharged into the Pacific Ocean on 11 March 2011, following the Fukushima Daiichi nuclear disaster triggered by the Tōhoku earthquake and tsunami. Three of the plant's reactors experienced meltdowns, leaving behind melted fuel debris. Water was introduced to prevent the meltdowns from progressing further. When cooling water, groundwater, and rain came into contact with the melted fuel debris, they became contaminated with radioactive nuclides, such as iodine-131, caesium-134, Caesium-137, and strontium-90.
Over 500,000 tonnes of untreated wastewater (including 10,000 tonnes released to free up storage space) escaped into the ocean shortly after the accident. In addition, persistent leakage into groundwater was not admitted by the plant operator until 2013. The radioactivity from these sources exceeded legal limits.
Since then, contaminated water has been pumped into storage units and gradually treated using the Advanced Liquid Processing System (ALPS) to eliminate most radionuclides, except notably tritium with a half-life of 12.32 years. In 2021, the Japanese cabinet approved the release of ALPS-treated water containing tritium. Because it is still radioactive immediately after treatment, the solution will be diluted by sea water to a lower concentration before being discharged.
A review report by the International Atomic Energy Agency (IAEA) shows that the plan of discharging diluted ALPS-treated water into the sea is consistent with relevant international safety standards. It also emphasizes that the release of the treated water is a national decision by the Government of Japan and its report is neither a recommendation nor an endorsement of the decision.
On , the power plant started releasing the treated portion of its wastewater into the Pacific Ocean. At the time, its storage units held over a million tonnes of wastewater in total. Because new wastewater is constantly being formed and even treated water must be discharged slowly by diluting it with more sea water, the entire process could take more than 30 years. The decision to release this water into the ocean has faced concerns and criticism from other countries and international organisations.
As of the fourth round of discharge in March 2024, no abnormal tritium levels have been detected in nearby waters.
Initial atmospheric release
Radioactive materials were dispersed into the atmosphere immediately after the disaster and account for most of all such materials leaked into the environment. 80% of the initial atmospheric release eventually deposited over rivers and the Pacific Ocean, according to a UNSCEAR report in 2020. Specifically, "the total releases to the atmosphere of Iodine-131 and Caesium-137 ranged generally between about 100 to about 500 PBq [petabecquerel, 1015 Bq] and 6 to 20 PBq, respectively. The ranges correspond to about 2% to 8% of the total inventory of Iodine-131 and about 1% to 3% of the total inventory of Caesium-137 in the three operating units (Units 1–3)".
Deposition on river
The indirect deposition to rivers come from the earlier direct discharge to the atmosphere. "Continuing indirect releases of about 5 to 10 TBq [terabecquerel, 1012 Bq] of Caesium-137 per year via rivers draining catchment areas", according to the UNSCEAR report in 2020.
Discharge to ocean, untreated water (2011)
On 5 April 2011, the operator of the nuclear plant, Tokyo Electric Power Company (TEPCO), discharged 11,500 tons of untreated water into the Pacific Ocean in order to free up storage space for water that is even more radioactive. The untreated water was the least radioactively contaminated among the stored water, but still 100 times the legal limit. TEPCO estimated that a total of 520,000 tons of untreated radioactive water had escaped into the ocean before it could place silt fences to contain further spills.
The UNSCEAR report in 2020 determined "direct releases in the first three months amounting to about 10 to 20 PBq [petabecquerel, 1015 Bq] of Iodine-131 and about 3 to 6 PBq of Caesium-137". About 82 percent having flowed into the sea before 8 April 2011.
Discharge to soil and groundwater by leakage
Scientists suspected that radioactive elements continued to leak into the ocean. High levels of caesium-134 were found in local fish, despite the isotope's comparatively shorter half-life. Meanwhile, radiation levels in the nearby sea water did not fall as expected. After repeated denials, the operator of the nuclear plant, Tokyo Electric Power Company (TEPCO), finally admitted on 22 July 2013 that leaks to groundwater had been happening. Some groundwater samples contained 310 Bq/L of cesium-134 and 650 Bq/L of cesium-137, exceeding WHO's maximum guideline of 10 Bq/L for drinking water.
It was later determined that some of the leaks came from the storage tanks for wastewater. Since then, TEPCO has had a record of being dishonest on its figures and has lost the public trust. For instance, in 2014, TEPCO blamed its own measuring method and revised the strontium in a groundwater well in July 2013 from 900,000 Bq/L to 5,000,000 Bq/L, which is 160,000 times the standard for discharge.
While soil naturally absorbs the caesium in groundwater, strontium and tritium can flow through more freely. At one time, nearly 400 tonnes of radioactive water was being formed every day (150,000 tonnes per year). TEPCO has since tried to stem or divert the inflow of groundwater to the damaged reactor sites and prevent contaminated water from escaping into the ocean.
The UNSCEAR report in 2020 concluded "Direct release of about 60 TBq [terabecquerel, 1012 Bq] of caesium-137 in ground water draining from the site up to October 2015, when measures were taken to reduce these releases, and about 0.5 TBq per year thereafter".
In February 2024, a leak at the power plant was detected by a contractor and eventually repaired by TEPCO. The company estimated that 5.5 tonnes of water, which potentially contained 22 billion becquerels of radioactive materials such as caesium and strontium, had escaped from an air vent, pooled outside and seeped into the surrounding soil, but did not leave the plant compound. It said this was caused by 10 out of 16 valves being left open when they should have been closed for flushing.
Discharge to ocean, treated water
Advanced Liquid Processing System (2013–)
To prevent the reactor meltdowns from worsening, a continuous supply of new water is necessary to cool the melted fuel debris. As of 2013, 400 metric tonnes of water was becoming radioactively contaminated each day. The contaminated water is pumped out and combined into the reactor-cooling loop, which includes stronium–cesium removal (KURION, SURRY) and reverse osmosis desalination processes.
In October 2012, TEPCO introduced the "Advanced Liquid Processing System" (ALPS, ), which is designed to remove radionuclides other than tritium and carbon-14. ALPS works by first pre-processing the water by iron coprecipitation (removes alpha nuclides and organics) and carbonate coprecipitation (removes alkali earth metals including strontium elements). The water is then passed through 16 absorbent columns to remove nuclides.
Wastewater is pumped to ALPS along with the concentrated saltwater from desalination. As some tritium still remains, even treated water would require dilution to meet drinkable standards. Although carbon-14 is not removed, the content in pre-treatment water is low enough to meet drinkable standards without dilution.
Japan's Nuclear Regulation Authority (NRA) approved the design of ALPS in March 2013. ALPS is to be run in three independent units and will be able to purify 250 tons of water per day. Unit "A" started operation in April. In June, unit A was found to be leaking water and shut down. In July, the cause was narrowed down to chloride and hypochlorite corrosion of water tanks; TEPCO responded by adding a rubber layer into the tanks. By August, all systems were shut down awaiting repair. One unit was expected to come online by September, with full recovery planned by the end of 2013.
By September 2018, TEPCO reports that 20% of the water had been treated to the required level.
By 2020, the daily buildup of contaminated water was reduced to 170 metric tonnes thanks to groundwater isolation installations. TEPCO reports that 72% of the water in its tanks, some from early trials of ALPS, needed to be repurified. The portion of ready-to-discharge water raised to 34% by 2021, and to 35% by 2023.
Some scientists expressed reservations due to potential bioaccumulation of ruthenium, cobalt, strontium, and plutonium, which sometimes slip through the ALPS process and were present in 71% of the tanks.
Japanese approval and monitoring (2021-)
Since the 2011 Fukushima Daiichi nuclear disaster, the nuclear plant has accumulated 1.25 million tonnes of waste water, stored in 1,061 tanks on the land of the nuclear plant, as of March 2021. It will run out of land for water tanks by 2022. It has been suggested the government could have solved the problem by allocating more land surrounding the power plant for water tanks, since the surrounding area had been designated as unsuitable for humans. Regardless, the government was reluctant to act. Mainichi Shimbun criticized the government for showing "no sincerity" in "unilaterally push[ing] through with the logic that there will no longer be enough storage space"
On 13 April 2021, the Cabinet of Prime Minister Suga unanimously approved that TEPCO dump the stored water to the Pacific Ocean over a course of 30 years. The Cabinet asserted the dumped water will be treated and diluted to drinkable standard. The idea of dumping had been floated by Japanese experts and officials as early as June 2016.
In April 2023, Japan's NRA announced a Comprehensive Radiation Monitoring Plan, in which the concentration of radionuclides in food (land and sea), soil, water, and air will be continually monitored across Japan. NRA also set up a system to monitor the radionuclide concentration in ALPS-processed water in order to verify TEPCO's readings.
International testing
An IAEA task force was dispatched to Japan in 2021, and they released their first report in February 2022. Among other findings, TEPCO has demonstrated to IAEA that their pump setup thoroughly mixes waters in tanks.
In May 2023, 3 IAEA laboratories and 4 national laboratories participated in an interlaboratory comparison to verify TEPCO's testing of ALPS-treated water. Out of the 30 radionuclides TEPCO regularly tests for, 12 were found to be above detection limits. 52 out of 53 results were found to agree with the combined result; the only problematic result was of I-129, where Korea Institute of Nuclear Safety reported a value too low compared to the weighted average. TEPCO's methology was found to be fit for purpose: although it is less sensitive for actinides than some participating labs, the detection limits were far enough from regulatory limits, and the alpha-emission screening test appears accurate enough. TEPCO's testing method for Am-141 may require additional review. The same sample was tested by Japan's NRA with no disagreements found.
The tritium that is not filtered out has a radioactivity of 148,900 Bq/L, compared to 620,000 Bq/L before treatment. TEPCO intends to dilute it down to 1,500 Bq/L or less before release.
Discharge into the Pacific Ocean (2023–)
On 22 August 2023, Japan announced that it would start releasing treated radioactive water from the tsunami-hit Fukushima nuclear plant into the Pacific Ocean in 48 hours, despite opposition from its neighbours. Japan says the water is safe after the use of Advanced Liquid Processing System (ALPS), which removes nearly all traces of radiation from the wastewater, with tritium being the primary exception to this. As a result, Japan has committed to diluting the water in order to bring levels of tritium below the regulatory standards set by the International Atomic Energy Agency. The International Atomic Energy Agency has stated that the plan meets safety standards, but critics contend that more studies need to be done and the release should be halted. On 24 August, Japan began the discharge of treated waste water into the Pacific Ocean, sparking protests in the region and China to expand its ban to all aquatic imports from Japan. Over 1 million tonnes of treated wastewater will be released by Japan over the next thirty years as per the plan.
On August 25, TEPCO reported that the amount of tritium in seawater around Fukushima has remained below the detection limit of 10 Bq/L. The Japanese Fishery Agency reported that fish caught 4 km away from the discharge pipe contained no detectable amounts of tritium.
In March 2024, the discharge was suspended temporarily after the Fukushima coastal region experienced another 5.8-magnitude earthquake. No abnormalities were detected with the wastewater treatment.
Reactions
Official nuclear science panels
The Japanese expert panel "ALPS subcommittee", chaired by nuclear scientist Ichiro Yamamoto, released a report in January 2020 which calculated that discharging all the water to the sea in one year would cause a radiation dose of 0.81 microsieverts to the locals, therefore it is negligible as compared to the Japanese' natural radiation of 2,100 microsieverts per year. Its calculations were verified by International Atomic Energy Agency to be correct.
Japanese public
A panel of public policy professors pointed out the lack of research on the harmful effects of tritium. It also criticized the government being insincere on accepting alternative disposal proposals as the proposals were always shelved after "procedural" discussion.
A survey by Asahi Shimbun in December 2020 found, among 2,126 respondents, that 55% of Japanese opposed dumping and 86% worried about international reception. Opposition is strongest among fishers and coastal communities.
The Fukushima Fishery Cooperatives was given written promises by TEPCO's CEO Hirose Naomi in 2015 that TEPCO would not dump the water before consulting the fishery industry. The Cooperatives felt bypassed and betrayed by the government's decision.
In August 2023, fisheries minister Tetsuro Nomura called the treated radioactive water "contaminated" but later apologised and retracted the statement after receiving an instruction from Prime Minister Fumio Kishida.
International reactions
Opposed to discharge
The South Korean government has been concerned since 2019 that Japan's release of radioactive water from Fukushima could be non-compliant with Article 2 of the London Protocol to protect the marine environment, but the Japanese government says the release is not applicable because it is a land-based pollution.
In June 2020, Baskut Tuncak, United Nations's Special Rapporteur on toxics and human rights, wrote on Japan's Kyodo News that the communities of Fukushima have the right not to be exposed deliberately to additional radioactive contamination." Greenpeace and five other UN Rapporteurs (including Clément Nyaletsossi Voule) issued condemnation echoing those sentiments.
Various governments have voiced concerns, including the governments of South Korea, North Korea, Taiwan, China, Russia, Germany, the Philippines, New Zealand, Belize, Costa Rica, Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, Panama, and Mexico.
In June 2021, at least 70 U.S. civic groups condemned Japan's wastewater discharge plan, and 17 civic organizations from various countries held protests in Berlin.
In January 2023, the U.S. National Association of Marine Laboratories expressed their opposition to the plan and stated that "there was a lack of adequate and accurate scientific data supporting Japan's assertion of safety".
In June 2023, South Korean shoppers rushed to buy up salt and other items prior to the expected release of the treated discharge. The South Korean government had banned seafood from the waters near Fukushima and says it will closely monitor the radioactivity level of salt farms. A similar salt rush occurred in China, after the discharge began.
In the months leading up to the start of discharge, over 80 per cent of South Koreans surveyed opposed the dumping, and over 60 per cent indicated intention to avoid seafood products after the release begins.
In August 2023, the Green Party of the United States issued a press release opposing the discharge.
In the same month, Shaun Burnie, senior nuclear specialist for Greenpeace, accused the Japanese government and TEPCO of diverting attention away from the radiation levels in the waste water from the nuclear plant by emphasizing tritium, arguing that various other harmful radionuclides, including strontium-90, iodine, ruthenium, rhodium, antimony, tellurium, cobalt, and carbon-14, will remain present even after filtration.
On 24 August, protests against the discharge erupted in South Korea, Hong Kong and Tokyo. According to the organisers, about 50,000 people gathered in Seoul. Some attempted to storm the Japanese embassy there.
Japanese shops reported receiving spam calls from China, prompting the Japanese government to summon a Chinese diplomat in response. A man threw stones into a Japanese school in Qingdao, and eggs were thrown into one in Suzhou, with no confirmed damage. Social media campaigns in China called for a boycott of Japanese products. This drove a 14% single-day stock price decline for luxury cosmetics conglomerate Shiseido.
Chinese state media outlets ran paid ads denouncing the water release on Facebook and Instagram in multiple countries and languages. Analysts labeled it part of a concerted disinformation campaign.
The Chinese government, Hong Kong, Macau, and the South Korean government have banned aquatic imports from some or all regions of Japan.
In support of discharge
U.S. Secretary of State Antony Blinken stated on 13 April 2021, "We thank Japan for its transparent efforts in its decision to dispose of the treated water". US Climate Envoy John Kerry expressed support.
On 14 June 2023, Palau President Surangel Whipps Jr. expressed understanding of Japan's plan to release the treated waste water into the sea, remarking "The people who would be impacted most are their own people. [...] And if it's acceptable to their people, it should be acceptable to all of us."
On 23 August 2023, Fijian Prime Minister Sitiveni Rabuka expressed support for the IAEA report, stating that the Japanese plan met international safety standards and most of the waste water would be discharged into Japan's "own backyard".
Mixed
Micronesia had expressed strong opposition to Japan releasing the water. In February 2023, however, President of the Federated States of Micronesia David Panuelo said he trusted Japan's intention and capabilities but stopped short of offering full support, saying that he would continue to consult with Japan to ensure the water's safety.
IAEA report
On 23 March 2021, Rafael Grossi, director-general of the International Atomic Energy Agency (IAEA), reached a consensus with the Japanese government three weeks before its announcement of decision to release water from the damaged power plant.
In February 2023, Robert H. Richmond, a marine biologist consulting for the Pacific Islands Forum (PIF), expressed doubts about the data behind Japan's plan. He pointed out that whereas the PIF is focused more on people and the ocean, the IAEA "has a mandate to promote the use of nuclear energy" and "there are alternatives" to discharging the water.
In July 2023, the IAEA released its conclusion that Japan's plans to slowly discharge the treated wastewater are in accordance with the relevant international safety standards but stopped short of endorsing the decision, which is for Japan's government to make.
Arjun Makhijani, president of the Institute for Energy and Environmental Research, criticised the IAEA for not looking into its own safety principle of justification, that is, whether an action's benefit outweighs its cost, because the IAEA was approached to make a report after Japan had already decided to discharge the water.
On 10 July 2023, New Zealand expressed confidence in the IAEA report.
On 9 August 2023, during a Nuclear Non-Proliferation Treaty (NPT) committee, Australia, France, Italy, Malaysia, United Kingdom, and the United States expressed support for the IAEA report. Australia said it was "independent, impartial and science-based" and trusts it completely, the UK also said it can be trusted, and the US said the report was impartial. South Korea requested that the IAEA inspect every step of the discharging, while China said the report was insufficient and urged Japan not to proceed with its plan. Australia expressed confidence in the IAEA report again on 23 August.
Pacific Islands Forum
In April 2021, the Pacific Islands Forum expressed deep concerns and urged Japan to rethink its decision on the discharge of the ALPS Treated Water.
In August 2023, a panel of five independent experts consulting for the Pacific Islands Forum was split on the issue of discharge. Some had no issue with it, saying it would not harm the Pacific. Two of them said trying to obtain information from Japan was difficult and its data had "red flags". The panelists wrote that more study is needed on the contaminants inside the water tanks, that TEPCO only took small samples from a quarter of the tanks, which showed large variations in readings, and used commercial pellets, not tritium-exposed fish, as food source for its experiments. Ken Buesseler, a scientist at the Woods Hole Oceanographic Institution (WHOI), does not expect widespread direct health effects across the Pacific but said contaminants missed by ALPS could accumulate near the shore in Japan and ultimately hurt fisheries in local areas. He recommended keeping them on land instead and mixing into concrete, for example, which would have been easier to monitor.
Environmental effects
Initial discharge
A large amount of caesium entered the sea from the initial atmospheric release (see above). By 2013, the concentrations of caesium-137 in the Fukushima coastal waters were around the level before the accident. However, concentrations in coastal sediments declined more slowly than in coastal waters, and the amount of caesium-137 stored in sediments most likely exceeded that in the water column by 2020. The sediments may provide a long-term source of caesium-137 in the seawater. According to Buesseler, the release of strontium-90 could be more problematic because, unlike some of the other isotopes, it gets into a person's bones.
Data on marine foods indicates their radioactive concentrations are falling towards initial levels. 41% of samples caught off the Fukushima coast in 2011 had caesium-137 concentrations above the legal limit (100 becquerels per kilogram), and this had declined to 0.05% in 2015. United States Food and Drug Administration stated in 2021 that "FDA has no evidence that radionuclides from the Fukushima incident are present in the U.S. food supply at levels that are unsafe". Yet, presenting the science alone has not helped customers to regain their trust on eating Fukushima fishery products.
2023 discharge
The most prevalent radionuclide in the wastewater is tritium. A total of 780 terabecquerels (TBq) will be released into the ocean at a rate of 22 TBq per year.
Tritium is routinely released into the ocean from operating nuclear power plants, sometimes in much greater quantities. For comparison, the La Hague nuclear processing site in France released 11,400 TBq of tritium in the year of 2018. In addition, about 60,000 TBq of tritium is produced naturally in the atmosphere each year by cosmic rays.
Other radionuclides present in the wastewater, like caesium-137, are not normally released by nuclear power plants. However, the concentrations in the treated water is minuscule relative to regulation limits.
"There is consensus among scientists that the impact on health is minuscule, still, it can't be said the risk is zero, which is what causes controversy", Michiaki Kai, a Japanese nuclear expert, told AFP. David Bailey, a physicist whose lab measures radioactivity, said that with tritium at diluted concentrations, "there is no issue with marine species, unless we see a severe decline in fish population".
Ferenc Dalnoki-Veress, a scientist-in-residence at the Middlebury Institute of International Studies at Monterey, said regarding dilution that bringing in living creatures makes the situation more complex. Robert Richmond, a biologist from the University of Hawaii, told the BBC that the inadequate radiological and ecological assessment raises the concern that Japan would be unable to detect what enters the environment and "get the genie back in the bottle". Dalnoki-Veress, Richmond, and three other panelists consulting for the Pacific Islands Forum wrote that dilution may fail to account for bioaccumulation and exposure pathways that involve organically-bound tritium (OBT).
Presenting the science alone has yet to gain public trust, as the government's attitude was deemed insincere by the public.
See also
2011 Tōhoku earthquake and tsunami
2011 Fukushima nuclear disaster
London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter
Nuclear power in Japan
References
External links
Basic policy on handling of the ALPS treated water, Ministry of Economy, Trade and Industry, Japan
Treated water portal, TEPCO
Current ALPS treated water, etc. conditions , TEPCO
Measurement and Analysis Results for Contaminated Water Treatment, TEPCO, reports ALPS outlet and tank storage concentrations
Data from the treated water discharge, International Atomic Energy Agency – Live data
– review describing ALPS technology and performance written by Finnish scientists using publicly-available information
Fukushima Daiichi nuclear disaster
Environmental issues in Japan
Water pollution in Japan
Water supply and sanitation in Japan
Fishing industry in Japan
Natural history of Japan
Nature conservation in Japan
Environmental controversies
2011 in Japan
2021 in Japan
2011 in the environment
2011 industrial disasters
2011 Tōhoku earthquake and tsunami
Radiation accidents and incidents
INES Level 7 accidents
History of the Pacific Ocean
Environmental impact of nuclear power | Discharge of radioactive water of the Fukushima Daiichi Nuclear Power Plant | [
"Technology"
] | 5,497 | [
"Environmental impact of nuclear power"
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67,386,286 | https://en.wikipedia.org/wiki/Iphigenia%20Photaki | Iphigenia Photaki (, ; also known after marriage as Iphigenia Vourvidou-Photaki, ; 1921–1983) was a Greek organic chemist remembered for her contributions in peptide chemical synthesis, especially in the synthesis of biologically/enzymatically active peptides.
Photaki was in 1965 the fourth woman overall to be habilitated in a scientific discipline in Greece, and the second to do so in the field of Chemistry. She specialised in peptide synthesis, influenced by her mentor and doctoral advisor Leonidas Zervas, a global authority on the subject. After distinguished research in Basel, Athens, and later Cornell, Photaki eventually rose to Professor of Organic Chemistry and Head of the Laboratory of Organic Chemistry of the University of Athens.
Biography
Early life, start of career and Basel
Photaki was born in Corinth in 1921 and finished her secondary education at the 2nd Girls' Gymnasium of Athens in 1938. In the same year she enrolled at the Department of Chemistry in the University of Athens, where she specialised in Organic chemistry under the mentorship of Leonidas Zervas. Her studies were interrupted during the Axis occupation of Greece when the Laboratory of Organic Chemistry was destroyed and Zervas was imprisoned as a member of the Greek Resistance. Photaki was finally awarded her degree summa cum laude in 1946 and subsequently continued her postgraduate studies under Zervas, earning her PhD in 1950 with a dissertation regarding glucosamine. Concurrently, she held a paid laboratory assistant position at the university already from 1943, carrying on as a research assistant until 1953.
In 1953, Photaki was awarded a scholarship to conduct research in Basel after examinations by the Greek State Scholarships Foundation. At the University of Basel she worked in the Laboratory of Organic Chemistry, at the time headed by Nobel laureate Tadeusz Reichstein. For the first two years of her stay (1953–1955) she was part of the Max Brenner research group, later moving as an independent scientific associate of Hans Erlenmeyer. Upon returning to Greece, she initially worked at the biochemical lab of the Evangelismos Hospital before being invited by Zervas to the nascent National Hellenic Research Foundation (NHRF) which he had helped found.
Cornell and later career in Athens
Photaki was selected in 1962 by the US Department of Health, Education and Welfare among an international pool of candidates to conduct research by the side of Nobel laureate Vincent du Vigneaud at Cornell University. While in New York, she also delivered a short series of lectures both in Cornell and at the National Institutes of Health (NIH).
Back in the University of Athens after Cornell, Photaki continued her research and was soon habilitated in 1965 following a thesis on oxytocin, building on the work she started under du Vigneaud. Despite her internationally distinguished research and sizeable recent grants from the NHRF and the United States NIH, she was not allowed to teach by the Greek military junta until 1969 and was intensively interrogated by the Cities Police Security Directorate on account of her anti-dictatorial political beliefs.
Photaki's teaching career was purposefully hindered by the Ministry of Education until the restoration of democracy in 1974; indeed, in 1975 she was promoted to extraordinary professor, a decade after receiving her habilitation. Shortly afterwards, in 1977, she was promoted to full professor (as Professor of Organic Chemistry) and Head of the Organic Chemistry Laboratory, both positions once held by her mentor Zervas. Photaki died in 1983 at the age of 62.
She was reported to spend very long hours at the laboratory, occasionally from "8 in the morning till 10 in the evening". In her 20-year career as a member of the University of Athens faculty, she supervised (alone or jointly with other colleagues) more than 15 doctoral dissertations.
Scientific work
Although many of Photaki's important contributions were related to peptide synthesis, her scientific work touched on a large number of topics within organic synthesis. In total she published around 50 papers in international English- or German-language chemical journals.
Peptide synthesis
Continuing and expanding the tradition of the University of Athens within the subject, starting from Zervas of Bergmann-Zervas carbobenzoxy method fame, Photaki initially worked on further refinement of suitable protecting groups for oligopeptide synthesis. She investigated with Zervas new types of protection such as N-protection with benzyl phosphate esters (N-phosphamide derivatives), S-protection using trityl, benzhydryl or benzoyl groups (as part of the greater effort for the synthesis of asymmetric cysteine-containing peptides), N-protection using the o-nitrophenylsulfenyl (NPS) group discovered in their Athens laboratory, or S-protection using the p-methoxycarbobenzoxy group (a modification of the Z group).
With the above methodologies she embarked on the synthesis of complex polypeptides, especially fragments of enzyme active sites and peptide hormones. Some notable achievements in papers Photaki co-authored include the first synthesis of the 20-membered insulin intra-chain ring or –following her research under du Vigneaud– several previously inaccessible oxytocin analogues (e.g. 4-deamido-oxytocin) and a novel oxytocin synthesis via a different route than the du Vigneaud synthesis.
In later years she also examined the preparation of biologically active atypical peptides such as Nω-arginine or lanthionine-containing peptides.
Other research
With her expertise on peptide synthesis, Photaki examined the biocatalytic properties and kinetics of enzyme active site analogues she prepared.
Another research topic she developed in the early part of her career was the chemical transformation of carbohydrates and glycosylated species, such as the stereoselective conversion of D-glucosamine to L-serinaldehyde which formed the basis of her doctoral thesis.
Finally, she examined some of the coordination complexes formed by histidine-containing peptides with , , and , and after the antitumour properties of platinum complexes were realised, she also worked on the peptide enzymatic reactions in the presence of amine complexes.
Honours and awards
In 1970 Iphigenia Vourvidou-Photaki was awarded the one-off Georgios Panopoulos Prize of the Academy of Athens, presented to her for "...her research on the chemical synthesis of polypeptide hormones and investigation of enzyme active sites, which constitute an internationally notable contribution of Greek science to the modern discipline of Chemistry".
During her lifetime, she was invited many times as a distinguished researcher in academic conferences related to her subject; some examples were the personal invitations she received to the 3rd European Peptide Symposium (EPS) (Basel, 1960), the 5th EPS (Oxford, 1962), 6th EPS (Athens, 1963 as organiser), 6th International Biochemistry Conference (New York, 1964), 7th EPS (Budapest, 1964), Symposium on Natural Sulfur Compounds (Copenhagen, 1966), NATO Seminar of Molecular Biology (Spetses, 1966), 8th EPS (Noordwijk, 1966), 9th EPS (Paris, 1968), 10th EPS (Abano, 1970), 11th EPS (Vienna, 1971), 3rd American Peptide Symposium (APS) (Boston, 1972), 13th EPS (Kiryat, 1974), 4th APS (New York, 1975), and the 14th EPS (Wépion, 1976) over which she presided.
References
Greek chemists
Greek women chemists
Organic chemists
1921 births
1983 deaths
Academic staff of the National and Kapodistrian University of Athens
20th-century Greek scientists
Scientists from Athens
People from Corinth | Iphigenia Photaki | [
"Chemistry"
] | 1,625 | [
"Organic chemists"
] |
67,388,883 | https://en.wikipedia.org/wiki/Battersia | Battersia is a genus of algae belonging to the family Sphacelariaceae.
The genus name of Battersia is in honour of Edward Arthur Lionel Batters (1860–1907), an English botanist and author of "A catalogue of the British Marine algae" in 1902.
The species of this genus are found in Europe and Northern America.
Species known:
Battersia arctica
Battersia plumigera
References
Brown algae
Brown algae genera | Battersia | [
"Biology"
] | 89 | [
"Algae",
"Brown algae"
] |
67,388,913 | https://en.wikipedia.org/wiki/Sphacelariaceae | Sphacelariaceae is a family of algae belonging to the order Sphacelariales.
Genera:
Battersia Reinke ex Batters, 1890
Chaetopteris Kützing, 1843
Herpodiscus G.R.South, 1974
Onslowia
Sphacelaria Lyngbye, 1818
Sphacella Reinke, 1890
Sphacelorbus Draisma, Prud'homme & H.Kawai, 2010
References
Brown algae
Brown algae families | Sphacelariaceae | [
"Biology"
] | 101 | [
"Algae",
"Brown algae"
] |
67,389,126 | https://en.wikipedia.org/wiki/Belonastrum | Belonastrum is a genus of diatom with uncertain classification.
Species:
Belonastrum berolinense (Lemmermann) Round & Maidana
References
Diatoms
Diatom genera | Belonastrum | [
"Biology"
] | 42 | [
"Diatoms",
"Algae"
] |
67,389,627 | https://en.wikipedia.org/wiki/Personal%20initiative | Personal initiative (PI) is self-starting and proactive behavior that overcomes barriers to achieve a goal. The concept was developed by Michael Frese and coworkers in the 1990s .
The three facets of PI – self-starting, future oriented, and overcoming barriers form a syndrome of proactive behaviors relating to each other empirically. Self-starting implies that the goals are set by an individual themselves and not by someone else. These self-started goals are often related to future orientation that involves having long-term focus and preparation for future demands and problems. Future demands can be met by proactive actions – 'pro' meaning preparatory or beforehand in Greek. Thus, a proactive approach attempts to get pre-signals signifying future obstacles and developing plans to prevent them. Implementation of long-term goals often leads to new setbacks. Initiative, therefore, implies that one will overcome these barriers actively and persistently.
PI stands in contrast to a passive approach, which is characterized by doing what one is told, giving up when faced with difficulties, and reacting to environmental demands. Proponents of PI have argued that it may become more important in future workplaces as they require a high degree of self-reliance.
PI is often conceptualized as the behavioral component of the general proactivity concept; it is also related but not identical to work engagement.
Relevance
PI is developed as a performance outcome within the action (regulation) theory tradition. While PI is consistently linked to higher work performance and innovativeness of individuals, it also interacts with other types of constructs of intrinsic motivation. The PI concept was used to create an effective training tool, which is now being used to help thousands of entrepreneurs and organisations in developing countries to improve their businesses.
Climate
PI Climate refers to formal and informal organizational practices which guide and support a proactive, self-starting, and persistent approach toward work. Studies have shown that individual personal initiative is related to idea generation, entrepreneurial success , and innovation implementation behavior. Similarly, a climate that fosters personal initiative helps to predict radical innovation as well as profitability of firms. As problems appear during the implementation of an innovation, innovation paired with a low level of climate for initiative may negatively affect company performance.
There may be higher uncertainty with new production systems leading to unexpected problems and barriers that need to be overcome; PI climate helps here to avoid production breakdowns. For firm performance there is an interaction between process innovation and climate for personal initiative - climate for personal initiative functions as a moderator. Organizations that display a work environment characterized by personal initiative have a higher chance of promoting the effectiveness of process innovations.
Facets of PI
PI suggests a model for training with action sequence goal setting, information gathering and prognosis, plan development and execution, plan monitoring, and feedback processing. The facet theory of PI depicted in the table provides a general concept of active performance from an action theory perspective. Every step of the action sequence can be supported by PI.
Training entrepreneurs
PI was used to create an effective training tool for entrepreneurs and micro-businesses in developing countries to improve their effectiveness. PI training has been studied with randomized controlled trials and shown to be successful. It leads to a proactive entrepreneurial mindset. Participants learn ways to set themselves apart from other businesses, as well as to anticipate problems, overcome setbacks, improve opportunity planning skills, and do other long-term planning. Not every experiment on PI training was successful, however the impact of personal initiative training was higher in a large randomised controlled filed experiment than Traditional Business training.
Consequences
Positive outcomes
Higher PI workers benefit positively in their careers via several avenues including:
Increased innovativeness in their goals, clearer career plans, and a higher degree of execution in these goals and plans.
Increased employability.
Increased political savviness, innovation, and likelihood to take the initiative advancing their careers.
Increased career proactivity, initiative, and progression.
Increased performance, both in the role of an employee as well as in the role of an entrepreneur.
Increased and continuous education resulting in individuals being able to work more effectively.
Potentially negative outcomes
PI can also have negative outcomes for employees. Showing PI can be harmful on different levels: for the employees themselves, for teammates, and for the entire organization. If management expects employees to be proactive, it may burden employees with extreme aspirations. On the organizational level, high PI among employees may reduce the possibility of the organizations to control and to socialize members of the organization.
References
Human behavior | Personal initiative | [
"Biology"
] | 907 | [
"Behavior",
"Human behavior"
] |
67,390,119 | https://en.wikipedia.org/wiki/Flore%20des%20Mascareignes | The Flore des Mascareignes (Fl. Mascar.) is a flora, in French, covering the three islands in the Mascarenes: Réunion, Mauritius and Rodrigues.
Project history
The project began in 1970 with the agreement signed in 1971, prepared jointly by the Institut de Recherche pour le Développement (IRD), the Mauritius Sugar Industry Research Institute (MSIRI), and the Royal Botanic Gardens, Kew. The completion of the Flora was funded by the EC's European Development Fund (1996).
The first editors appointed were J. Bosser (Editor-in-Chief), W. Marais, and Dr. R. Julien, with Dr. R.E. Vaughan as adviser. The first taxonomist was M.J.E. Coode, who worked on the Flora until the end of 1975; he was replaced by I.B.K. Richardson in 1976, who spent 6 weeks collecting in the Mascarenes. The first fascicule of the Flora was published in 1976. The final two volumes, covering the orchids, were published in 2023.
The Flora treats the native flora in detail, including ferns, but includes naturalised and commonly cultivated plants.
Editors have been R. Antoine (MSIRI), J.C. Autrey (MSIRI), J. Bosser (IRD), J.P.M. Brenan (Kew), J. Heslop-Harrison (Kew), I.K. Ferguson (Kew), G.Mangenot (ORSTOM), C. Soopramanien (MSIRI).
Flora
The Mascarenes have a high level of endemism, about 65%, with some shared between the islands of the archipelago. Others are found only on a single island, Rodrigues (47), Réunion (165) and Mauritius (273). Some are already extinct while most are threatened.
Botanical history
There has been a long history of botanical studies on the islands of Mauritius and Réunion. The botany of Rodriguez was not studied until 1879.
-
-
Geology
The Mascarenes are volcanic in origin. Reunion is the largest island, formed about 3 million years ago, rising to 3070m with an active volcano. Mauritius and Rodrigues were formed about 8-10 million years ago. Mauritius consists of large plains with steep mountains surrounding them, the remnants of an old caldera, that are only 828m high. Rodrigues is the smallest of the islands and is much eroded, reaching 398m high at Mt Limon.
Families
References
External links
Checklist of flowering plants of the island of Mauritius, Indian Ocean
Flore de la Reunion
Mascarine-Cadetiana
Mascarenes
Flora of the Mascarene Islands | Flore des Mascareignes | [
"Biology"
] | 573 | [
"Flora",
"Florae (publication)"
] |
67,390,901 | https://en.wikipedia.org/wiki/Induction%2C%20bounding%20and%20least%20number%20principles | In first-order arithmetic, the induction principles, bounding principles, and least number principles are three related families of first-order principles, which may or may not hold in nonstandard models of arithmetic. These principles are often used in reverse mathematics to calibrate the axiomatic strength of theorems.
Definitions
Informally, for a first-order formula of arithmetic with one free variable, the induction principle for expresses the validity of mathematical induction over , while the least number principle for asserts that if has a witness, it has a least one. For a formula in two free variables, the bounding principle for states that, for a fixed bound , if for every there is such that , then we can find a bound on the 's.
Formally, the induction principle for is the sentence:
There is a similar strong induction principle for :
The least number principle for is the sentence:
Finally, the bounding principle for is the sentence:
More commonly, we consider these principles not just for a single formula, but for a class of formulae in the arithmetical hierarchy. For example, is the axiom schema consisting of for every formula in one free variable.
Nonstandard models
It may seem that the principles , , , are trivial, and indeed, they hold for all formulae , in the standard model of arithmetic . However, they become more relevant in nonstandard models. Recall that a nonstandard model of arithmetic has the form for some linear order . In other words, it consists of an initial copy of , whose elements are called finite or standard, followed by many copies of arranged in the shape of , whose elements are called infinite or nonstandard.
Now, considering the principles , , , in a nonstandard model , we can see how they might fail. For example, the hypothesis of the induction principle only ensures that holds for all elements in the standard part of - it may not hold for the nonstandard elements, who can't be reached by iterating the successor operation from zero. Similarly, the bounding principle might fail if the bound is nonstandard, as then the (infinite) collection of could be cofinal in .
Relations between the principles
The following relations hold between the principles (over the weak base theory ):
for every formula ;
;
, and both implications are strict;
;
, but it is not known if this reverses.
Over , Slaman proved that .
Reverse mathematics
The induction, bounding and least number principles are commonly used in reverse mathematics and second-order arithmetic. For example, is part of the definition of the subsystem of second-order arithmetic. Hence, , and are all theorems of . The subsystem proves all the principles , , , for arithmetical , . The infinite pigeonhole principle is known to be equivalent to and over .
References
Formal theories of arithmetic
Mathematical axioms
Predicate logic | Induction, bounding and least number principles | [
"Mathematics"
] | 588 | [
"Predicate logic",
"Mathematical logic",
"Mathematical axioms",
"Formal theories of arithmetic",
"Basic concepts in set theory",
"Arithmetic"
] |
67,391,449 | https://en.wikipedia.org/wiki/Coral%20reefs%20of%20Kiribati | The Coral reefs of Kiribati consists of 32 atolls and one raised coral island, Banaba (Ocean Island), which is an isolated island between Nauru and the Gilbert Islands. The islands of Kiribati are dispersed over of the Pacific Ocean and straddle the equator and the 180th meridian, extending into the eastern and western hemispheres, as well as the northern and southern hemispheres. 21 of the 33 islands are inhabited. The groups of islands of Kiribati are:
Gilbert Islands: 16 atolls located some north of Fiji.
Phoenix Islands: 8 atolls and coral islands located some southeast of the Gilberts.
Line Islands: 8 atolls and one reef, located about east of the Gilberts.
The recognizable reef systems in these archipelagos are: 3 reef communities or submerged reefs; 15 fringing reefs; and 18 atolls. In the Line Islands archipelago, Kingman Reef, Jarvis Island and Palmyra Atoll are U.S. territories that are administered as part of the United States Minor Outlying Islands, although they are geographically part of the Line Islands archipelago. Kingman Reef, Jarvis Island and Palmyra Atoll are part of the Pacific Islands Heritage Marine National Monument.
The reefs in the Gilbert Islands are exposed to the effects of pollution and over-utilisation of the reef resources by the residents of the islands, which is similar to the threats to the Coral reefs of Tuvalu, which are to the south east of the Gilbert Islands. In contrast, most of atolls of the Phoenix Islands and Line Islands are uninhabited.
The isolation of the Phoenix Islands, most of which are uninhabited, means they are among the most pristine coral reefs on Earth.
Areas of high biodiversity and conservation value
Key Biodiversity Areas
A total of 22 Key Biodiversity Areas (KBAs) - areas of high biodiversity and conservation value - have been identified in Kiribati, with the KBAs encompassing both marine and terrestrial systems (such as bird nesting or feeding environments). The 22 identified KBAs cover an approximate total area of or approximately 74% of the total land, lagoon and reef habitat of Kiribati. As of 2013, 12 of the 22 KBAs have been completely or partially established as conservation areas by the government of Kiribati or by local village communities.
The North Tarawa Conservation Area includes marine zones.
Four marine reserves were specifically set aside for the conservation of grouper. These are all located in the Gilbert Islands on the atolls of Butaritari, Tabiteuea, Nonouti, and Onotoa and are managed by the Fisheries Division.
Phoenix Islands Protected Area
The 2006 declaration of the Phoenix Islands Protected Area (PIPA), with a size of , created, at that time, the world's largest designated marine protected area (MPA), which was also designated as the world's largest and deepest UNESCO World Heritage Site in 2010. The U.S. administered Pacific Islands Heritage Marine National Monument is currently the world's largest designated MPA, and is to the north and north-east of the PIPA.
The PIPA constitutes 11.34% of Kiribati's Exclusive Economic Zone (EEZ). The PIPA conserves one of the world's largest intact oceanic coral archipelago ecosystems, includes 14 known underwater seamounts (presumed to be extinct volcanoes) and other deep-sea habitats. The area contains approximately 800 known species of fauna, including about 200 coral species, 500 fish species, 18 marine mammals and 44 bird species. In total it is equivalent to the size of the state of California in the U.S., though the total land area is only .
There are three atolls with associated lagoons and perimeter coral reefs in the PIPA, Orona (Hull), Nikumaroro (Gardner), and Canton Island (Abariringa), and five low islands surrounded by fringing reefs, Manra (Sydney), Rawaki (Phoenix), McKean, Birnie and Enderbury, and also two submerged reefs, Winslow and Carondelet. The area contains seven main habitats: island, lagoon, coral reef, deep reef, seamount, deep benthos, and open ocean, which are all represented within PIPA and the Kanton Island protection zone.
In the PIPA Management Plan 2015–2020, which was implemented following a Kiribati government decision in January 2014, there is a total ban on commercial fishing within the PIPA boundaries extending to the limits of the Territorial Sea (to 12 nm) and in all lagoons of the 8 PIPA islands, (Canton, Manra, Rawaki, Birnie, Mckean, Enderbury, Nikumaroro and Orona) to ensure there is no impact to marine and terrestrial species including habitats.
Two submerged reefs, Winslow and Carondelet, and at least 14 known seamounts together with open ocean and deep-sea habitat are an integral part of the Phoenix Islands Protected Area. The New England Aquarium (NEAq) and Woods Hole Oceanographic Institution have carried out scientific research expeditions of these seamount habitats, which have been identified being rich in deep-water coral and biodiversity supporting a variety of oceanic pelagic species. PIPA has been identified as an important feeding and spawning site for species of tuna. The dominant taxonomic group across all depths were the octocorals, followed by antipatharians, scleractinians, and then zoantharians.
, Canton Island had a population of 20, down from 61 in 2000. Because it is inhabited, management of Canton Island is described in the Canton Resource Use Sustainability Plan (KRUSP), which covers a 12 nm radius around the atoll. Over 50% of the island and lagoon are protected in a conservation zone.
Structure of the reefs of Kiribati
The coral atolls and reef islands of Kiribati have been formed from oceanic volcanos, with a coral reef growing around the shore of the volcano and then, over several million years, the volcano becomes extinct, eroded and subsided completely beneath the surface of the ocean. The reef and the small coral islets on top of it are all that is left of the original island, and a lagoon has taken the place of the former volcano.
For the atoll to persist, the coral reef must be maintained at the sea surface, with coral growth matching any relative change in sea level (subsidence of the island or rising oceans). On the atolls, an annular reef rim surrounds the lagoon, and may include natural reef channels.
Banaba is an elevated limestone cap surrounded by a fringing reef. The low islands of Makin, Tamana, Arorae, Enderbury, Flint and Vostok Island all lack lagoons but have a fringing reef.
State of the reefs of Kiribati
Gilbert Islands
The reef environment of Kiribati includes approximately 200 species of corals and about 1,000 species of shellfish. The species of shellfish include the black-lipped pearl oyster (Pinctada margaritifera) and Anadara cockles (Anadara uropigimelana), and also the strombid gastropod (Strombus luhuanus).
In the Central Gilbert Islands atolls of Abaiang, Abemama and Maiana, 3 species of giant clam (Tridacna) occur: Tridacna squamosa; Tridacna maxima; and Hippopus hippopus), although the stocks of the giant clam have been largely exhausted.
Blue coral (Heliopora coerulea) is abundant on the reefs of the Gilbert Islands, such as on Tarawa although it is rarer on the windward reefs, in contrast to the more protected seaward reefs. Blue coral is absent from the Phoenix Islands and the Line Islands. On the reefs of Tarawa the dominant species are Acropora muricata and Acropora hyacinthus, with extensive patches of Corallimorpharia and Porites rus along the southern seaward reef slope, large colonies of Plerogyra sinuosa are also present. The coral reef environment of Abaiang in the Northern Gilbert Islands includes: the occasional stand of Acropora (staghorn and table corals) and massive Porites rus; and on the western seaward reef of Abaiang are blue coral (Heliopora coerulea) and colonies of Porites cylindrica; with mixed species of Halimeda sp. (green macroalgae).
Phoenix Islands
The 2000 surveys identify that, at the time of these surveys, the reefs were in an excellent state of health, and free from the bleaching that has plagued reefs in other parts of the Pacific with no evidence of any coral diseases.
The coral reefs of the Phoenix Islands were notable for their moderate Live Coral Cover (LCC) of 20-40% and evidence of high physical breakage of coral by wave energy on the southern, eastern and northern reefs of the islands (the windward sides), which create coral rubble in the lagoons and base of the reefs. The dominant bottom cover of the lagoons was hard coral (36.0%), followed by coralline algae (red algae) (18.0%), coral rubble (16.7%), turf and fleshy algae (11.6%) and Halimeda (green macroalgae) (10.4%). The dominance of coral and coralline algae indicates healthy reef ecosystems dominated by calcifying organisms and active reef framework growth.
The effect of exposure to storms is indicated by the dominance trends with storm resistant encrusting/submassive forms in windward sites, its somewhat lower abundance at leeward sites and a corresponding increase in more delicate plate forms, and the dominance of the more fragile table and staghorn corals in protected lagoon sites. Coral species diversity is higher on the larger islands of Nikumaroro, Kanton and Orona, which indicates the importance of the larger area of reef on these islands for support of biodiversity. Carpeting soft corals (Sinularia and Lobophytum) were found at the bottom of the lagoons of Kanton and Orona, which are the only true lagoons in the Phoenix Islands.
Crown-of-thorns starfish (Acanthaster planci), cushion star and other coral predators, such as the corallivorous snail Drupella spp., are found on the reefs of the Phoenix Islands, although there has not been any indication of destructive outbreaks of those predators on the reefs.
Species of giant clam (Tridacna) occur in low numbers: Tridacna squamosa, Tridacna maxima, but not Tridacna gigas.
The 2000 surveys identified the following coral species as being the most abundant coral species at the specific sites on each atoll that was surveyed:
Line Islands
Kiritimati (Christmas Island) in the Line Islands has the greatest land area of any coral atoll in the world, at about . The atoll is about in perimeter, while the lagoon shoreline extends for over . The entire island is a Wildlife Sanctuary.
Surveys of the Northern Line Islands in 2007 identified a shifted from domination by reef-building stony corals and coralline algae (red algae) at Kingman Reef and Palmyra Atoll (both are U.S. territory), to domination by macroalgae (including species of Halimeda (green macroalgae), Caulerpa, Avrainvillea, Dictyosphaeria and Lobophora) and algal turfs at Tabuaeran and especially Kiritimati (both are part of Kiribati). Coral density tracked coral cover and was highest at Kingman Reef and lowest at Kiritimati.
Stony corals plus coralline algae strongly dominated the reefs at Kingman Reef (71% LCC) with numerous large coral colonies (primarily table and branching Acropora spp.). Cover of stony corals plus coralline algae dropped to 48% LCC at Palmyra, 38% LCC at Tabuaeran, and 21% LCC at Kiritimati. The types of coral were much more variable at Tabuaeran than the other atolls. Some sites on the reefs at Tabuaeran were dominated by coralline algae and Acropora corals (maximum 63% combined cover), whereas other sites were dominated by fleshy algae (79% combined cover of turf and macro-algae). However, turf algae were the most common group overall (36% cover), whereas dead corals carpeted by turf and macroalgae more uniformly dominated the reefs at Kiritimati (68% mean combined cover). The numbers of juvenile colonies to of Acropora, Pocillopora and Fungiidae corals, were more than 6 times higher at Kingman Reef and Palmyra than at Tabuaeran and Kiritimati.
Giant clams (Tridacna) were also more abundant at Kingman Reef than elsewhere in the Line Islands. Clams are harvested for consumption at Kiritimati.
Some coral species that remain at risk in Kiribati due to the gaps in the protection of Key Biodiversity Areas include: Acropora echinata (procumbens), Acropora vaughani, Alveopora verrilliana, and Montipora patula, all recorded only on Tabuaeran in the Line Islands.
Bleaching
There has been bleaching of the (Acropora spp.) staghorn branching corals and other corals on the reefs of Kiribati. Bleaching is a process that expels the photosynthetic algae from the corals' "stomachs" or polyps. This algae is called zooxanthellae. It is vital to the reef's life because it provides the coral with nutrients; it is also responsible for the color. The process is called bleaching because when the algae is ejected from the coral reef the animal loses its pigment. Zooxanthella densities are continually changing; bleaching is an extreme example of what naturally happens.
The bleaching was a consequence of an increase in ocean temperatures that happened during the El Niño events that occurred between 2003 and 2004, including on the reefs of Kiritimati, the reefs of the Central Gilbert Islands and the Southern Gilbert Islands, and on reefs in the lagoon of Kanton, which is in the Phoenix Islands Protected Area. Research dives in 2009 and 2012 had shown little improvement in the coral colonies of the lagoon of Kanton. Then research dives in 2015 found abundant Acropora spp staghorn branching corals.
Survey data (2004–2012) of the El Niño-influenced coral reefs in the Central Gilbert and Southern Gilbert Islands allowed for the evaluate the drivers of coral community response to, and recovery from, multiple heat stress events. The results showed more limited bleaching during the 2009–2010 El Niño event, in contrast to a similar 2004–2005 event. This difference was correlated with incoming light and historical temperature variability, rather than heat stress. The researchers concluded there was growing resistance to bleaching-level heat stress among coral communities, due to the spread of “weedy” and temperature-tolerant species (such as Porites rus) and cloudy conditions during El Niño events.
Impact of iron leaching from shipwrecks
The PIPA is in a naturally iron poor region. The introduction of iron oxides to this environment from the rusting shipwrecks and anchor gear, is linked to proliferation of turf algae and benthic bacterial communities, and degraded ‘black reefs’. Monitoring from 2000 to 2015 recorded the black reef originating at the 1929 wreck of the SS Norwich City on Nikumaroro progressing northward to sites away. The 2015 expedition to the PIPA recorded the presence of black reefs on five atolls (Kanton, Nikumaroro, McKean, Rawaki, Enderbury) and on Carondelet seamount associated with shipwreck debris. No recovery has been documented at black reefs observed between 2005 and 2015.
Bibliography
References
Kiribati
Geography of Kiribati | Coral reefs of Kiribati | [
"Biology"
] | 3,353 | [
"Biogeomorphology",
"Coral reefs"
] |
76,039,382 | https://en.wikipedia.org/wiki/BlueOS | Vivo BlueOS, or BlueOS also named Blue River OS, is a open-source distributed operating system developed by Vivo. The OS is designed to support large models and multi-modal functions in variety of inputs it supports.
BlueOS also supports the BlueXlink connection protocol, which adopts a distributed design concept, similar to HarmonyOS and compatible with industry-standard protocols. This allows data to be securely transferred and accessed between multiple devices. On the security architecture, Rust language is supported on the operating system for security advancements.
BlueOS aims to run on various devices, including devices that has low as 32 MB of RAM that targets a wide range of devices, from smart home appliances and wearables.
Vivo has not announced plans to install BlueOS on its smartphones in the early stage of the new operating system development. This meant that custom Funtouch OS and OriginOS operating systems based on AOSP remains to be the default operating systems for Vivo smartphones.
On November 13, 2023, Vivo Watch 3, becomes the first device from the company that ships with the new operating system.
It reportedly supports different hardware architectures, with multiple POSIX standards which supports Linux kernel alongside its own RTOS kernel in its multikernel architecture and similar to OpenHarmony and HarmonyOS in distributed operating systems in terms of the Kernel Abstraction Layer. It also supports application technology standards and Vivo provides developers with software development kits, BlueOS (Blue River) SDK and BlueOS Studio (Blue River Studio) IDE based on VS Code for rich applications. The operating system also contains AI service engines and multi-mode input subsystems based on large AI model capabilities, providing multi-modal input and output, among other benefits.
History
It has reportedly been in development since 2018, the operating system core is written with the Rust programming language, which is open source, released on November 1, 2023, via 2023 Vivo Developer Conference. It is independent of the Android operating system used on Vivo smartphones. The operating system is intended for lightweight IoT devices and Wearables.
It's also reported that Vivo expects that its Copilot tool with its large language model that is able to provide code, image and text generation, in addition to other capabilities for the operating system.
See also
OpenHarmony
HarmonyOS
References
External links
2023 software
Embedded operating systems
Internet of things
Wearable computers
Smartwatches
Free software operating systems
ARM operating systems | BlueOS | [
"Technology"
] | 497 | [
"Smartwatches"
] |
76,040,232 | https://en.wikipedia.org/wiki/Julian%20Sahasrabudhe | Julian Sahasrabudhe (born May 8, 1988) is a Canadian mathematician who is an assistant professor of mathematics at the University of Cambridge, in their Department of Pure Mathematics and Mathematical Statistics. His research interests are in extremal and probabilistic combinatorics, Ramsey theory, random polynomials and matrices, and combinatorial number theory.
Life and education
Sahasrabudhe grew up on Bowen Island, British Columbia, Canada. He studied music at Capilano College and later moved to study at Simon Fraser University where he completed his undergraduate degree in mathematics. After graduating in 2012, Julian received his Ph.D. in 2017 under the supervision of Béla Bollobás at the University of Memphis.
Following his Ph.D., Sahasrabudhe was a Junior Research Fellow at Peterhouse, Cambridge from 2017 to 2021. He currently holds a position as an assistant professor in the Department of Pure Mathematics and Mathematical Statistics (DPMMS) at the University of Cambridge.
Career and research
Sahasrabudhe's work covers many topics such as Littlewood problems on polynomials, probability and geometry of polynomials, arithmetic Ramsey theory, Erdős covering systems, random matrices and polynomials, etc. In one of his more recent works in Ramsey theory, he published a paper on Exponential Patterns in Arithmetic Ramsey Theory in 2018 by building on an observation made by the Alessandro Sisto in 2011. He proved that for every finite colouring of the natural numbers there exists such that the triple is monochromatic, demonstrating the partition regularity of complex exponential patterns. This work marks a crucial development in understanding the structure of numbers under partitioning.
In 2023, Sahasrabudhe submitted a paper titled An exponential improvement for diagonal Ramsey along with Marcelo Campos, Simon Griffiths, and Robert Morris. In this paper, they proved that the Ramsey number
This is the first exponential improvement over the upper bound of Erdős and Szekeres, proved in 1935.
Sahasrabudhe has also worked with Marcelo Campos, Matthew Jenssen, and Marcus Michelen on random matrix theory with the paper The singularity probability of a random symmetric matrix is exponentially small. The paper addresses a long-standing conjecture concerning symmetric matrix with entries in . They proved that the probability of such a matrix being singular is exponentially small. The research quantifies this probability as where is drawn uniformly at random from the set of all symmetric matrices and is an absolute constant.
In 2020, Sahasrabudhe published a paper named Flat Littlewood Polynomials exists, which he co-authored with Paul Ballister, Bela Bollobás, Robert Morris, and Marius Tiba. This work confirms the Littlewood conjecture by demonstrating the existence of Littlewood polynomials with coefficients of that are flat, meaning their magnitudes remain bounded within a specific range on the complex unit circle. This achievement not only validates a hypothesis made by Littlewood in 1966 but also contributes significantly to the field of mathematics, particularly in combinatorics and polynomial analysis.
In 2022, the authors worked on Erdős covering systems with the paper On the Erdős Covering Problem: The Density of the Uncovered Set. They confirmed and provided a stronger proof of a conjecture proposed by Micheal Filaseta, Kevin Ford, Sergei Konyagin, Carl Pomerance, and Gang Yu, which states that for distinct moduli within the interval , the density of uncovered integers is bounded below by a constant. Furthermore, the authors establish a condition on the moduli that provides an optimal lower bound for the density of the uncovered set.
Awards and honours
In August 2021, Julian Sahasrabudhe was awarded the European Prize in Combinatorics for his contribution to applying combinatorial methods to problems in harmonic analysis, combinatorial number theory, Ramsey theory, and probability theory. In particular, Sahasrabudhe proved theorems on the Littlewood problems, on geometry of polynomials (Pemantle's conjecture), and on problems of Erdős, Schinzel, and Selfridge.
In October 2023, Julian Sahasrabudhe was awarded with the Salem Prize for his contribution to harmonic analysis, probability theory, and combinatorics. More specifically, Sahasrabudhe improved the bound on the singularity probability of random symmetric matrices and obtained a new upper bound for diagonal Ramsey numbers.
Sahasrabudhe is a 2024 recipient of the Whitehead Prize, given "for his outstanding contributions to Ramsey theory, his solutions to famous problems in complex analysis and random matrix theory, and his remarkable progress on sphere packings".
Publications
Selected research articles
Exponential Patterns in Arithmetic Ramsey Theory (2018)
Flat Littlewood polynomials exist (2020)
The singularity probability of a random symmetric matrix is exponentially small (2021)
On the Erdős Covering Problem: the density of the uncovered set (2022)
An exponential improvement for diagonal Ramsey (2023)
References
External links
Dr Julian Sahasrabudhe – Faculty of Mathematics
Combinatorics from the zeros of polynomials – Oxford Discrete Maths and Probability Seminar
21st-century Canadian mathematicians
Combinatorialists
Cambridge mathematicians
Living people
1988 births
People from Greater Vancouver
Simon Fraser University alumni
University of Memphis alumni | Julian Sahasrabudhe | [
"Mathematics"
] | 1,062 | [
"Combinatorialists",
"Combinatorics"
] |
76,040,732 | https://en.wikipedia.org/wiki/Amir%20Sagi | Amir Sagi (Hebrew: אמיר שגיא, born May 22, 1956) is a professor of life sciences at Ben Gurion University of the Negev, whose field of expertise is crustacean biology, physiology, endocrinology, and functional genomics. He contributed to the study of sexual differentiation, cell growth and aquaculture.
Early life and education
Sagi completed his MSc, in oceanography and marine biology at The Hebrew University of Jerusalem which marked the start of his interest in crustacean reproduction strategies. and during his PhD he addressed anatomical and physiological aspects of differentiation in prawns, with special attention to the androgenic gland.
Research and career
His postdoctoral training in comparative endocrinology was at the University of Connecticut and the Marine Biological Laboratory at Woods Hole, Massachusetts. under Prof Hans Laufer. Sagi than moved to Ben Gurion University of the Negev (1992) in which he was promoted to the degree of full professor of life sciences (2005), and distinguished professor (since 2018).
He was also president of the International Society for Invertebrate Reproduction and Development (ISIRD) between 2011 and 2013, and held various roles within academic and professional committees such as Dean of the Faculty of Natural Sciences at Ben Gurion University of the Negev (2008–2011) and as a board member of the National Institute for Biotechnology in the Negev.
Sagi's group has discovered the IAG physiological sexual switch, and its associated gene expression in decapods investigating multigenic functions in crustacean reproduction and growth and the establishment of genome editing in prawns using application of CRISPR.
His group established monosex biotechnologies in crustacean culture including the application of temporal RNA interference (RNAi) in the field of aquaculture for all-male culture. Crustacean monosex technologies are applied in Vietnam, Thailand, China, Malaysia, Israel. He is a co-founder of the all-female culture biotech company Enzootic Ltd.
Prawns are efficient predators thus might serve as sustainable and responsible biocontrol agents over various invasive and pest species. The Sagi lab development of monosex prawn biotechnologies enables the application of responsible, efficient, and non-invasive biocontrol agents in various parts of the world.
Prof. Amir Sagi has received the Lifetime Achievement Award at the ACEEU Asia-Pacific Triple E Awards in Malaysia 2024, recognizing his contributions to aquaculture biotechnology over the past two decades.
Awards and honors
Vice President and Dean of R&D Award for Breakthrough Research (2022)
ICA award for leading entrepreneurship in agriculture and biotechnology (2018)
The Crustacean Society Excellence in Research Award (2015 -16)
The Landau Prize for Sciences and Arts (2014)
The Global Aquaculture Alliance's inaugural Novus Global Aquaculture Innovation Award (2013)
Lily and Sidney Oelbaum Chair in Applied Biochemistry
Lifetime Achievement Award at the ACEEU Asia-Pacific Triple E Awards, 2024.
Recognition from the Bard Foundation for his contribution to aquaculture and global food security, 2024
References
Living people
1956 births
Israeli biologists
Carcinologists
Biotechnologists | Amir Sagi | [
"Biology"
] | 659 | [
"Biotechnologists"
] |
76,042,134 | https://en.wikipedia.org/wiki/Americium%20trihydride | Americium trihydride is a binary inorganic compound of americium and hydrogen with the chemical formula .
Physical properties
The compound crystalyzes with a hexagonal crystal structure. Stable at low temperatures.
Chemical properties
Reaction of americium trihydride with nitrogen at 750 °C produces americium nitride:
References
Americium compounds
Hydrogen compounds | Americium trihydride | [
"Chemistry"
] | 76 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
76,042,182 | https://en.wikipedia.org/wiki/Cer6%20%28retrotransposon%29 | Cer6 is a LTR retrotransposon that is described from sequencing data in the chromosome III of C. elegans.
LTR retrotransposons
LTR retrotransposons are class I transposable element characterized by the presence of long terminal repeats (LTRs) directly flanking an internal coding region. As retrotransposons, they mobilize through reverse transcription of their mRNA and integration of the newly created cDNA into another location. Their mechanism of retrotransposition is shared with retroviruses, with the difference that most LTR-retrotransposons do not form infectious particles that leave the cells and therefore only replicate inside their genome of origin.
References
Further reading
Mobile genetic elements | Cer6 (retrotransposon) | [
"Chemistry",
"Biology"
] | 152 | [
"Mobile genetic elements",
"Biotechnology stubs",
"Biochemistry stubs",
"Molecular genetics",
"Biochemistry"
] |
76,042,281 | https://en.wikipedia.org/wiki/Lepiota%20decorata | Lepiota decorata, also known as the pink parasol, is an uncommon species of gilled mushroom found in North America. The cap of L. decorata usually has a speckled violet pattern, stains orange when scratched, and is about 4 to 8 cm in diameter.
Lepiota decorata is often found in rich soil and leaf litter below trees including coast live oak, alder, eucalyptus, and conifer. A similar, separate, as-yet-undescribed species is associated with Monterey cypress. Leucoagaricus roseolividus, a much more common mushroom, has a superficially similar appearance. L. decorata is possibly properly a Leucoagaricus but has not yet been moved over. Lepiota decorata was first described in Mycologia magazine by S. M. Zeller in 1929.
References
Fungi of North America
Fungi described in 1929
Fungus species
decorata
Taxa named by Sanford Myron Zeller | Lepiota decorata | [
"Biology"
] | 199 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
76,042,985 | https://en.wikipedia.org/wiki/Insignia%20%28Xbox%29 | Insignia is a non-commercial server hosting project currently in open beta that aims to restore the functionality of Xbox Live for the original Xbox. It provides a free service created via closed-source reverse engineering of the original Live server software, hosted on Insignia's own servers, and its aim is to support every title that had Xbox Live support. Some popular titles are either not supported yet or are supported on a limited basis. Games by Electronic Arts used their own servers that were not based on Xbox Live and cannot currently be supported.
Insignia can work on both unmodified and modified consoles, as well as Xbox emulators. To work on Insignia, a console has to be registered to Insignia's servers; the user can create an Xbox Live account similar to how it would have originally been done. Insignia is completely free-of-charge and has no monthly fee or initial signup price, though requires an email to register an account.
Insignia currently supports most features that worked on Xbox Live, such as matchmaking, leaderboards, friends support, game invites, clans, user generated content, voice chat, game title updates and DLC downloads for some games.
By January 2025 it has over 20,000 users registered and supports 198 of 339 games that used Xbox Live features.
History
Insignia was started in 2019 by two developers, Luke Usher and Billy, who decided to work together trying to make an Xbox Live replacement. Billy worked previously on replacement services for the Wii U and 3DS, and Luke was the lead developer of an open source Xbox emulator. Insignia was publicly announced in May 2020 and was planned to go live later that year. In July 2022, a closed alpha test was started. Insignia went into an open beta that November and supported 25 games at release; public signups had been open for one month before the beta.
By November 2022 around 7,000 people has signed up for the waiting list, and by December, 3,500 people were approved and 40 games were supported. By November 2023 it had reached up to 150 games and over 8,000 users.
A multiplayer servers for Halo 2 were launched in March 2024. Certain Affinity founder and Halo 2 map designer Max Hoberman was positive to its launch.
References
Servers (computing)
Xbox (console)
Xbox network | Insignia (Xbox) | [
"Technology"
] | 465 | [
"Computing stubs",
"Computer hardware stubs"
] |
76,043,343 | https://en.wikipedia.org/wiki/Cilium%20%28computing%29 | Cilium is a cloud native technology for networking, observability, and security. It is based on the kernel technology eBPF, originally for better networking performance, and now leverages many additional features for different use cases. The core networking component has evolved from only providing a flat Layer 3 network for containers to including advanced networking features, like BGP and Service mesh, within a Kubernetes cluster, across multiple clusters, and connecting with the world outside Kubernetes. Hubble was created as the network observability component and Tetragon was later added for security observability and runtime enforcement. Cilium runs on Linux and is one of the first eBPF applications being ported to Microsoft Windows through the eBPF on Windows project.
History
Evolution from Networking CNI (Container Network Interface)
Cilium began as a networking CNI for container workloads. It was originally IPv6 only and supported multiple container orchestrators, like Kubernetes. The original vision for Cilium was to build an intent and identity-based high-performance container networking platform. As the cloud native ecosystem expanded, Cilium added new projects and features to address new problems in the space.
The table below summarises some of the most significant milestones of this evolution:
December 2015 - Initial commit to the Cilium project
May 2016 - Network policy was added, expanding the scope beyond just networking
August 2016 - Cilium was initially announced during LinuxCon as a project providing fast IPv6 container networking with eBPF and XDP. Today, Cilium has been adopted by major cloud provider's Kubernetes offerings and is one of the most widely used CNIs.
August 2017 - ebpf-go was created as a library to read, modify, and load eBPF programs and attach them to various hooks.
April 2018 - Cilium 1.0 is the first stable release
November 2019 - Hubble was launched to provide eBPF-based observability to network flows
August 2020 - Chosen by Google as the basis for their Kubernetes Dataplane v2
September 2021 - AWS picks Cilium for Networking & Security on EKS Anywhere
October 2021 - Pwru was launched for tracing network packets in the Linux kernel with advanced filtering capabilities
October 2021 - Accepted into CNCF as an incubation level project
December 2021 - Cilium Service Mesh launched to help manage traffic between services
May 2022 - Tetragon open sourced to cover security observability and runtime enforcement
October 2022 - Chosen as CNI for Azure
April 2023 - Cilium Mesh launched to connect workloads and machines across cloud, on-prem, and edge
April 2023 - First CiliumCon hosted as a part of KubeCon
October 2023 - Cilium becomes a CNCF Graduated project
CNCF
Cilium was accepted into the Cloud Native Computing Foundation on October 13th, 2021 as an incubation-level project. It applied to become a graduated project on October 27th 2022. It became a Graduated project one year later. Cilium is one of the fastest-moving projects in the CNCF ecosystem.
Adoption
Cilium has been adopted by many large-scale production users, including over 100 that have stated it publicly, for example:
Datadog uses Cilium as their CNI and kube-proxy replacement
Ascend uses Cilium as their one CNI across multiple cloud providers
Bell Canada uses Cilium and eBPF for telco networking
Cosmonic uses Cilium for their Nomad-based PaaS
IKEA uses Cilium for their self-hosted bare-metal private cloud
S&P Global uses Cilium as its CNI
Sky uses Cilium as their CNI and for network security
The New York Times uses Cilium on EKS for multi-region multi-tenant shared clusters
Trip.com uses Cilium both on premise and in AWS
Cilium is the CNI for many cloud providers including Alibaba, APPUiO, Azure, AWS, DigitalOcean, Exoscale, Google Cloud, Hetzner, and Tencent Cloud.
Projects Overview
Cilium
Cilium began as a container networking project. With the growth of Kubernetes and container orchestration, Cilium became a CNI, providing basic things like configuring container network interfaces and Pod to Pod connectivity. From the beginning, Cilium based its networking on eBPF rather than iptables or IPVS, betting that eBPF would become the future of cloud native networking.
Cilium’s eBPF based dataplane provides a simple flat Layer 3 network with the ability to span multiple clusters in either a native routing or overlay mode with Cilium Cluster Mesh. It is Layer 7-protocol aware and can enforce network policies on Layer 3 to Layer 7 and with FQDN using an identity-based security model that is decoupled from network addressing.
Cilium implements distributed load balancing for traffic between Pods and to external services, and is able to fully replace kube-proxy, using XDP, socket-based load-balancing and efficient hash tables in eBPF. It also supports advanced functionality like integrated ingress and egress gateways, bandwidth management, a stand-alone load balancer, and service mesh.
Cilium is the first CNI to support advanced kernel features such as BBR TCP congestion control and BIG TCP for Kubernetes Pods.
Hubble
Hubble is the observability, service map, and UI of Cilium which is shipped with the CNI. It can be used to observe individual network packet flows, view network policy decisions to allow or block traffic, and build up service maps showing how Kubernetes services are communicating. Hubble can export this data to Prometheus, OpenTelemetry, Grafana, and Fluentd for further analysis of Layer 3/4 and Layer 7 metrics.
Tetragon
Tetragon is the security observability and runtime enforcement project of Cilium. Tetragon is a flexible Kubernetes-aware security observability and runtime enforcement tool that applies policy and filtering directly with eBPF. It allows users to monitor and observe the complete lifecycle of every process execution on their machine, translate policies for file monitoring, network observability, container security, and more into eBPF programs, and do synchronous monitoring, filtering, and enforcement completely in the kernel.
Go eBPF Library
ebpf-go is a pure-Go library to interact with the eBPF subsystem in the Linux kernel. It has minimal external dependencies, emphasises reliability and compatibility, and is widely deployed in production.
Pwru
pwru ("Packet, where are you?") is an eBPF-based tool for tracing network packets in the Linux kernel with advanced filtering capabilities. It allows fine-grained introspection of kernel state to facilitate debugging network connectivity issues. Under the hood, pwru attaches eBPF debugging programs to all Linux kernel functions which are responsible for processing network packets.
This gives a user finer-grained view into a packet processing in the kernel than with tcpdump, Wireshark, or more traditional tools. Also, it can show packet metadata such as network namespace, processing timestamp, internal kernel packet representation fields, and more.
Use Cases
Networking
Cilium began as a networking project and has many features that allow it to provide a consistent connectivity experience from Kubernetes workloads to virtual machines and physical servers running in the cloud, on-premises, or at the edge. Some of these include:
Container Network Interface (CNI) - Provides networking for Kubernetes clusters
Layer 4 Load Balancer - Based on Maglev and XDP for handling north/south traffic
Cluster Mesh - Combines multiple Kubernetes clusters into one network
Bandwidth and Latency Optimization - Fair Queueing, TCP Optimization, and Rate Limiting
kube-proxy replacement - Replaces iptables with eBPF hash tables
BGP - Integrates into existing networks and provides load balancing in bare metal clusters
Egress Gateway - Provides a static IP for integration into external workloads
Service Mesh - Includes ingress, TLS termination, canary rollouts, rate limiting, and circuit breaking
Gateway API - Fully conformant implementation for managing ingress into Kubernetes clusters
SRv6 - Defines packet processing in the network as a program
BBR support for Pods - Allows for better throughput and latency for Internet traffic
NAT 46/64 Gateway - Allows IPv4 services to talk with IPv6 ones and vice versa
BIG TCP for IPv4/IPv6 - Enables better performance by reducing the number of packets traversing the stack
Cilium Mesh - Connects workloads running outside Kubernetes to ones running inside it
Observability
Being in the kernel, eBPF has complete visibility of everything that is happening on a machine. Cilium leverages this with the following features:
Service Map - Provides a UI for network flows and policy
Network Flow Logs - Provides Layer 3/4 and DNS visibility connected to identity
Network Protocol Visibility - Including HTTP, gRPC, Kafka, UDP, and SCTP
Metrics & Tracing Export - Sends data to Prometheus, OpenTelemetry, or other storage system
Security
eBPF can stop events in the kernel for security. Cilium projects leverage this through the following features:
Transparent Encryption - Utilizes either IPSec or WireGuard
Network Policy - Includes Layer 3 to Layer 7 and DNS-aware policies
Runtime Enforcement - Stops processes outside of policies with default policies
File Integrity Monitoring - Tracks modification to the system
Release timeline
Support windows
The chart below visualises the period for which each Cilium community maintained release is/was supported:
Community
Cilium's official website lists online forums, messaging platforms, and in-person meetups for the Cilium user and developer community.
Conferences
Conferences dedicated to Cilium development in the past have included:
CiliumCon EU 2023, held in conjunction with KubeCon + CloudNativeCon EU 2023
CiliumCon NA 2023, held in conjunction with KubeCon + CloudNativeCon NA 2023
CiliumCon EU 2024, held in conjunction with KubeCon + CloudNativeCon EU 2024
CiliumCon NA 2024 held in conjunction with KubeCon + CloudNativeCon NA 2024
Annual Report
The Cilium community releases an annual report to cover how the community developed over the course of the year:
Cilium Annual Report 2022: Year of the CNI
Cilium Annual Report 2023: Year of Graduation
See also
Kubernetes
Cloud Native Computing Foundation
eBPF
References
External links
Cilium.io - Official Website
Cilium Repository on Github
Network software
Open-source cloud applications | Cilium (computing) | [
"Engineering"
] | 2,235 | [
"Network software",
"Computer networks engineering"
] |
76,043,408 | https://en.wikipedia.org/wiki/Ice%20Memory | Ice Memory is an international initiative which aims to constitute the first world library of archived glacier ice, to preserve this invaluable scientific heritage for the generations to come, when future techniques can obtain even more data from these samples.
In 2015, the Ice Memory project started with the meeting of Jérôme Chappellaz - CNRS - EPFL, Patrick Ginot - IRD (IGE/UGA-CNRS-IRD-G-INP) from France and Carlo Barbante (CNR/Ca’Foscari Univ. of Venice) from Italy to conduct drilling expeditions worldwide and safeguard the data present in the ice - the memory of the ice - in an sanctuary in Antarctica.
According to UNESCO and IUCN report "World Heritage glaciers: sentinels of climate change" announcing that about 30% of glaciers recognized as World Heritage Sites will disappear by 2050 and 50% by 2100 without a drastic and immediate reduction in greenhouse gases, the Ice Memory initiative has been described as urgent and meaningful for humanity wellbeing and acknowledged by UNESCO in 2017
Indeed, previous glaciology researches made by notably Claude Lorius, Glaciologist and Ice Memory first supporter, Dominique Raynaud and Jean Jouzel aimed to prove the link between atmospheric concentration of greenhouse gases and climate change while studying ice cores.
In the coming decades, it is expected that researchers will have new ideas and techniques to develop those scientific results. For instance, they may be able to isolate other information contained in the ice of which we are not aware today.
This scientific information trapped in the ice — synthesised and highlighted by the Intergovernmental Panel on Climate Change — is a useful element in the crucial decisions of how to shape international environmental and climate policy.
History
Since its beginnings in 2015, the Ice Memory project conducted nine drilling expeditions in France, Italy, Switzerland, Bolivia, Russia and Norway (Svalbard).
in 2023 at Colle del Lys / Italy, the team collected 2 ice cores of 105 and 106 m length recovering 150–200 years of planet history
in 2023 at Svalbard / Norway, the team collected 3 ice cores of 74 m length recovering 300–400 years of planet history
in 2022 at Kilimanjaro / Tanzania, the team could not reach the summit for diplomatic issues
in 2021 at Monte Rosa / Italy, the team collected 3 ice cores of 130 m length recovering 300–400 years of planet history
in 2020 at Grand Combin / Switzerland, the team collected 3 ice cores of 16, 18 and 26 m length
in 2018 at Elbrus / Russia, the team collected 2 ice cores of 150 and 120 m length recovering more than 500 years of planet history
in 2018 at Belukha / Russia, the team collected 2 ice cores of 160 and 106 m length
in 2017 at Illimani / Bolivia, the team collected 2 ice cores of 137 and 134 m length recovering 18 000 years of planet history,
in 2016 at Col du Dôme / France, the team collected 3 ice cores of 128 m length recovering more than 200 years of planet history
Ice core science
By trapping the different components of the atmosphere, ice represents an invaluable source of information for tracing our environmental past, for providing an account of past climate change, and especially for understanding our future.
Variations in temperature, atmospheric concentrations of greenhouse gases, natural aerosol emissions, pollutants produced by humans.
The science of ice cores can study the dozens of chemical compounds that are trapped in the ice: gases, acids, heavy metals, radioactivity, and water isotopes form the memory of the climates and environments of the past.
Ice Memory drillings roadmap
The objective of Ice Memory Foundation is to sample 20 glaciers in 20 years so that future generations of scientists will have access to undamaged high-quality ice cores to pursue their research and have data to understand the Earth's climate.
As of 2025, the Ice Memory Foundation would be storing glacier samples from Europe, Bolivia, and Eurasia Russia in Europe, while waiting for Antarctic storage to become available.
Co-founder of the Ice Memory Foundation, Jérome Chappellaz says that teams will collect ice from other sites, including Rocky mountains (Canada/ USA), Himalaya plateau (Tadjikistan, Pakistan, China), Andes plateau (Peru, Argentina), Heard island (Australia), as soon as possible, facing the accelerating rate of melting.
A sanctuary in Antarctica
The Ice Memory heritage ice cores will be safeguarded for centuries in Antarctica. A dedicated sanctuary will be built at the French-Italian Concordia station, an international station on the Antarctic Plateau that allows natural storage at -50 °C.
First tests of the cave have been jointly managed by IPEV and PNRA. The first cave should be available for the first Ice Memory cores in 2025. Located close to the Concordia Station, the storage site will cover a surface area equivalent to approximately twenty 20-foot containers, or approximately 300 m2.
Despite the added complexity of transporting the ice cores to Antarctica, this choice will allow a long-term preservation of the samples using natural storage with no energy consumption required for refrigeration thereby protecting the precious samples from any risk of disrupted cold chain (technical problems, economic crisis, conflict, acts of terrorism, etc.).
Difficult access to the samples, combined with restrictive Antarctic logistics will prevent an over-use of the cores. At last, the storage in a polar region managed via the Antarctic Treaty, prevents territorial claims as they are frozen, as signed by the world's major nations.
Ice Memory Foundation
The Ice Memory Foundation was officially created by seven major French, Italian, and Swiss scientific institutions in 2021: the CNRS, the IRD, University Grenoble Alpes, and the French Polar Institute (IPEV) in France; the Italian National Research Council (CNR) and Ca’ Foscari University of Venice in Italy; and the Paul Scherrer Institute (PSI) in Switzerland and is sheltered by University Grenoble Alpes Foundation.
Located in France at Université Grenoble Alpes, it aims to collect, save and manage ice cores from selected glaciers in the world currently melting, with their yielded information for decades and centuries to come.
The Foundation is directed by Anne Catherine Olhmann since 2015.
International long term governance
The Honorary President of the Ice Memory Foundation is His Serene Highness Prince Albert II of Monaco.
The Foundation's governance is international, with members from France, Italy, Switzerland, China, and the United States, including two former Intergovernmental Panel on Climate Change (IPCC) Vice Presidents, Qin Dahe and Jean Jouzel.
A long term governance over the next centuries, ensuring the preservation and the proper use of this Humanity heritage, is investigated in cooperation with International Institutions, notably UNESCO and Antarctic Treaty System (ATCM).
In 2023 at One Planet Polar Summit in Paris, the Ice Memory Law and Governance Chair was launched to establish proposals for filling existing legal gaps and to propose a legal framework for the development of the Ice Memory heritage.
References
External links
of the Ice Memory Foundation
Climate change and the environment
Library-related organizations
Environmental agencies
Environmental science | Ice Memory | [
"Environmental_science"
] | 1,461 | [
"nan"
] |
76,043,809 | https://en.wikipedia.org/wiki/Magnesium%20selenide | Magnesium selenide is an inorganic compound with the chemical formula MgSe. It contains magnesium and selenium in a 1:1 ratio. It belongs to the II-VI family of semiconductor compounds.
Structure
Three crystal structures for MgSe have been experimentally characterized. The rock-salt structure is considered to be the most stable crystal structure that has been observed in bulk samples of MgSe, and a cubic lattice constant of 0.55 nm was deduced for this structure. Although attempts at preparing pure zincblende MgSe have been unsuccessful, the lattice constant of zincblende MgSe has been extrapolated from epitaxial thin films of zincblende MgxZn1−xSySe1−x and MgxZn1−xSe grown on gallium arsenide, the latter of which was prepared with a high magnesium content (up to 95% Mg, i.e., Mg0.95Zn0.05Se). There is good agreement between these and other extrapolations that the lattice constant of pure zincblende MgSe is 0.59 nm. The wurtzite structure of MgSe has been observed, but it is unstable and slowly converts to the rock-salt structure.
NiAs- and FeSi-type crystal structures of MgSe are predicted to form by subjecting the rock-salt crystal structure to extremely high pressures.
Electronic properties
Both rock-salt and zincblende MgSe are semiconductors. On the basis of different extrapolations, a room temperature bandgap of 4.0 eV has been recommended for zincblende MgSe. A room temperature bandgap of 3.9 eV was determined for rock-salt MgSe.
Preparation
Thin films of amorphous, wurtzite and rock-salt MgSe have been prepared by vacuum deposition of Mg and Se at cryogenic temperatures, followed by heating and annealing. Compound semiconductor alloys of MgSe, such as MgxZn1−xSe, have been prepared by molecular beam epitaxy.
Reactions
Samples of pure MgSe and Mg-rich MgxZn1−xSe (x > 0.7) readily react with water and oxidize in air.
References
Magnesium compounds
Selenides
II-VI semiconductors | Magnesium selenide | [
"Chemistry"
] | 468 | [
"Semiconductor materials",
"II-VI semiconductors",
"Inorganic compounds"
] |
76,044,138 | https://en.wikipedia.org/wiki/List%20of%20boiling%20liquid%20expanding%20vapor%20explosions | The following is a list of boiling liquid expanding vapor explosion (BLEVE) accidents. It shows whether the accident occurred during dangerous goods transportation or at a fixed facility, the accident origin (e.g., storage, process reactor, rail tank car, tank truck), the material involved, its amount, the number of fatalities, and whether a fireball developed (which is typically the case if the material is flammable).
Boiler explosions are not listed here, see List of boiler explosions. Note, however, that not all boiler explosions are BLEVEs, with some being fuel–air explosions arising in the boiler furnace.
Gas cylinders explosions are listed only where many (typically tens of) canisters exploded in a single event.
List
See also
List of explosions
List of boiler explosions
List of tanker explosions
Lists of rail accidents
List of American railroad accidents
Explanatory notes
References
Sources
Gas explosions
Lists of explosions
Process safety | List of boiling liquid expanding vapor explosions | [
"Chemistry",
"Engineering"
] | 190 | [
"Gas explosions",
"Safety engineering",
"Natural gas safety",
"Process safety",
"Explosions",
"Chemical process engineering",
"Lists of explosions"
] |
76,044,342 | https://en.wikipedia.org/wiki/Arboreal%20Galois%20representation | In arithmetic dynamics, an arboreal Galois representation is a continuous group homomorphism between the absolute Galois group of a field and the automorphism group of an infinite, regular, rooted tree.
The study of arboreal Galois representations of goes back to the works of Odoni in 1980s.
Definition
Let be a field and be its separable closure. The Galois group of the extension is called the absolute Galois group of . This is a profinite group and it is therefore endowed with its natural Krull topology.
For a positive integer , let be the infinite regular rooted tree of degree . This is an infinite tree where one node is labeled as the root of the tree and every node has exactly descendants. An automorphism of is a bijection of the set of nodes that preserves vertex-edge connectivity. The group of all automorphisms of is a profinite group as well, as it can be seen as the inverse limit of the automorphism groups of the finite sub-trees formed by all nodes at distance at most from the root. The group of automorphisms of is isomorphic to , the iterated wreath product of copies of the symmetric group of degree .
An arboreal Galois representation is a continuous group homomorphism .
Arboreal Galois representations attached to rational functions
The most natural source of arboreal Galois representations is the theory of iterations of self-rational functions on the projective line. Let be a field and a rational function of degree . For every let be the -fold composition of the map with itself. Let and suppose that for every the set contains elements of the algebraic closure . Then one can construct an infinite, regular, rooted -ary tree in the following way: the root of the tree is , and the nodes at distance from are the elements of . A node at distance from is connected with an edge to a node at distance from if and only if .
The absolute Galois group acts on via automorphisms, and the induced homorphism is continuous, and therefore is called the arboreal Galois representation attached to with basepoint .
Arboreal representations attached to rational functions can be seen as a wide generalization of Galois representations on Tate modules of abelian varieties.
Arboreal Galois representations attached to quadratic polynomials
The simplest non-trivial case is that of monic quadratic polynomials. Let be a field of characteristic not 2, let and set the basepoint . The adjusted post-critical orbit of is the sequence defined by and for every . A resultant argument shows that has elements for ever if and only if for every . In 1992, Stoll proved the following theorem:
Theorem: the arboreal representation is surjective if and only if the span of in the -vector space is -dimensional for every .
The following are examples of polynomials that satisfy the conditions of Stoll's Theorem, and that therefore have surjective arboreal representations.
For , , where is such that either and or , and is not a square.
Let be a field of characteristic not and be the rational function field over . Then has surjective arboreal representation.
Higher degrees and Odoni's conjecture
In 1985 Odoni formulated the following conjecture.
Conjecture: Let be a Hilbertian field of characteristic , and let be a positive integer. Then there exists a polynomial of degree such that is surjective.
Although in this very general form the conjecture has been shown to be false by Dittmann and Kadets, there are several results when is a number field. Benedetto and Juul proved Odoni's conjecture for a number field and even, and also when both and are odd, Looper independently proved Odoni's conjecture for prime and .
Finite index conjecture
When is a global field and is a rational function of degree 2, the image of is expected to be "large" in most cases. The following conjecture quantifies the previous statement, and it was formulated by Jones in 2013.
Conjecture Let be a global field and a rational function of degree 2. Let be the critical points of . Then if and only if at least one of the following conditions hold:
The map is post-critically finite, namely the orbits of are both finite.
There exists such that .
is a periodic point for .
There exist a Möbius transformation that fixes and is such that .
Jones' conjecture is considered to be a dynamical analogue of Serre's open image theorem.
One direction of Jones' conjecture is known to be true: if satisfies one of the above conditions, then . In particular, when is post-critically finite then is a topologically finitely generated closed subgroup of for every .
In the other direction, Juul et al. proved that if the abc conjecture holds for number fields, is a number field and is a quadratic polynomial, then if and only if is post-critically finite or not eventually stable. When is a quadratic polynomial, conditions (2) and (4) in Jones' conjecture are never satisfied. Moreover, Jones and Levy conjectured that is eventually stable if and only if is not periodic for .
Abelian arboreal representations
In 2020, Andrews and Petsche formulated the following conjecture.
Conjecture Let be a number field, let be a polynomial of degree and let . Then is abelian if and only if there exists a root of unity such that the pair is conjugate over the maximal abelian extension to or to , where is the Chebyshev polynomial of the first kind of degree .
Two pairs , where and are conjugate over a field extension if there exists a Möbius transformation such that and . Conjugacy is an equivalence relation. The Chebyshev polynomials the conjecture refers to are a normalized version, conjugate by the Möbius transformation to make them monic.
It has been proven that Andrews and Petsche's conjecture holds true when .
References
Further reading
Arboreal Galois Representations Over Finite Fields
https://www.quora.com/What-is-the-significance-of-arboreal-Galois-representations
Arithmetic dynamics
Galois theory | Arboreal Galois representation | [
"Mathematics"
] | 1,245 | [
"Dynamical systems",
"Recreational mathematics",
"Arithmetic dynamics",
"Number theory"
] |
76,044,600 | https://en.wikipedia.org/wiki/Amoeboflagellate | An amoeboflagellate ( amoeboflagellates) is any eukaryotic organism capable of behaving as an amoeba and as a flagellate at some point during their life cycle. Amoeboflagellates present both pseudopodia and at least one flagellum, often simultaneously.
Occurrence
The amoeboflagellate cell type has been acquired numerous independent times across the evolution of protists (i.e. primarily unicellular eukaryotes that are not plants, fungi or animals). Some examples of protist phyla with amoeboflagellate body types are:
Cercozoa contains various examples of amoeboflagellates with filose pseudopods, thread-like cell projections also known as filopodia. The cercomonads, glissomonads and paracercomonads behave as amoeboflagellates with two flagella throughout the majority of their life cycle, and are essential predators of the soil microbiome. Among the more basal Cercozoa is Reticulamoeba, an amoeboflagellate with reticulose pseudopods (reticulopodia), filopodia that join into a net-like structure.
Amoebozoa contains several groups of amoeboflagellates with one or two flagella and lobose pseudopods, which are rounder and more blunt-ended than filopodia. Among them are the myxogastrids, a group of slime molds that behave as amoeboflagellates in various stages of their life cycle. Many species of Archamoebae, a more basal group, are anaerobic amoeboflagellates. Other examples are the dictyostelians, another group of slime molds, and the closely related varioseans, such as Phalansterium.
Breviatea, a small class related to animals, fungi and amoebozoans, is composed of anaerobic amoeboflagellates with two flagella.
Percolozoa contains amoeboflagellates with lobose pseudopods, but are differentiated by their flat mitochondrial cristae, not tubular as in Amoebozoa. A popular example is the genus Naegleria, whose members can change shape between an amoeba and a flagellate.
The amoeboflagellate phenotype is present in numerous protists that have a crucial phylogenetic position near the origin of animals and fungi, within the vast clade known as Opisthokonta. It has been described in choanoflagellates such as Salpingoeca, filastereans such as Pigoraptor, and even some early-branching fungi such as Sanchytrium, but it is absent in animals. The two species of Pluriformea have a wide range of cell types, from cellular aggregations to amoeboflagellates.
Notes
References
Motile cells
Cell biology
Amoeboids
Flagellates
Microbiology | Amoeboflagellate | [
"Chemistry",
"Biology"
] | 662 | [
"Cell biology",
"Microbiology",
"Microscopy"
] |
76,045,405 | https://en.wikipedia.org/wiki/Terbium%20nitride | Terbium nitride is a binary inorganic compound of terbium and nitrogen with the chemical formula .
Physical properties
Terbium nitride crystalyzes with cubic crystal system of the space group of F3m3.
Uses
Terbium nitride is used for high-end electronics, ceramics, luminescent materials, special metallurgy, petrochemical, artificial crystal, magnetic materials.
References
Nitrides
Terbium compounds
Nitrogen compounds | Terbium nitride | [
"Chemistry"
] | 96 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
76,045,590 | https://en.wikipedia.org/wiki/Susan%20Chomba | Susan Chomba is a Kenyan scientist and environmentalist. She is a director at the World Resources Institute.
Biography
Chomba grew up in poverty in Kirinyaga County. Chomba was largely raised by her grandmother as her mother, a single parent, was always working. Chomba's mother grew capsicum and French beans on a small plot of land owned by a step-uncle and created a farming cooperative.
When Chomba was nine, a local boarding school rejected her due to her poverty, so she attended one further away, in Western Kenya. When her mother was no longer able to afford to send her there, Chomba returned to Kirinyaga to attend the provincial high school. Each student in the school was given a patch of land to farm. Chomba experimented with organic farming, growing cabbage to withstand the cold climate.
Although Chomba had hoped to study law or agricultural economics, she was placed in a forestry course at Moi University. In her third year, when taking an agroforestry class, she found her calling.
Chomba joined the International Centre for Research in Agroforestry, where she Regreening Africa, an eight-country land restoration program that restored one million hectares of degraded land in Africa.
Chomba was a member of the first cohort to graduate with a dual European master's degree in Sustainable Tropical Forestry from Bangor University and the University of Copenhagen. She completed fieldwork in Tanzania. She continued to get her PhD in forest governance at the University of Copenhagen.
In 2021, Chomba joined the World Resources Institute as their Director of Vital Landscapes for Africa, where she leads their work on "Forests, Food systems and People." She is also a global ambassador for the Race to Zero and Race to Resilience under the UN High Level Champions for Climate Action.
Awards
Peter Henry Forestry Postgraduate Award, first recipient, Bangor University
2016: 16 Women Restoring the Earth, Global Landscapes Forum
2022: 25 women shaping climate action globally, Greenbiz
2023: 100 Women (BBC), which features 100 inspiring and influential women from around the world.
References
Kenyan scientists
Environmental scientists
Kenyan women scientists
Women agronomists
Alumni of Bangor University
University of Copenhagen alumni
Moi University alumni
Year of birth missing (living people)
Living people | Susan Chomba | [
"Environmental_science"
] | 462 | [
"Environmental scientists"
] |
76,045,846 | https://en.wikipedia.org/wiki/HD%2049434 | HD 49434 is a single star in the equatorial constellation of Monoceros. It is faintly visible to the naked eye with an apparent visual magnitude of 5.75. Based on parallax measurements the star is located at a distance of 130.5 light years from the Sun, but it is drifting closer with a radial velocity of −17 km/s.
During a study with the ELODIE spectrograph from 1998 onwards it was found to show low amplitude variations of absorption line profiles, which is an indication of non-radial pulsations. It also displays a long period, low amplitude variation in luminosity, which together suggest it is a Gamma Doradus variable. Observation of the star during the CoRoT mission showed ten pulsation frequencies, four of which are typical for Gamma Doradus variables and six higher frequencies that are characteristic of Delta Scuti variables. Hence it is classified as a hybrid pulsator.
The spectrum of HD 49434 presents as an F-type main-sequence star with stellar classification of F1V. It displays a high rotation rate with a projected rotational velocity of 86 km/s. The star has 1.55 times the mass of the Sun and 1.60 times the Sun's radius. It is radiating 7 times the luminosity of the Sun from its photosphere at an effective temperature of 7,632 K.
References
Further reading
F-type main-sequence stars
Gamma Doradus variables
Delta Scuti variables
Monoceros
2514
CoRoT
−01 1386
049434
032617 | HD 49434 | [
"Astronomy"
] | 319 | [
"CoRoT",
"Space telescopes",
"Monoceros",
"Constellations"
] |
76,047,279 | https://en.wikipedia.org/wiki/Bothe%E2%80%93Geiger%20coincidence%20experiment | In the history of quantum mechanics, the Bothe–Geiger coincidence experiment was conducted by Walther Bothe and Hans Geiger from 1924 to 1925. The experiment explored x-ray scattering from electrons to determine the nature of the conservation of energy at microscopic scales, which was contested at that time. The experiment confirmed existence of photons, the conservation of energy and the Compton scattering theory.
At that time, quantum mechanics was still under development in what was known as the old quantum theory. Under this framework, the BKS theory by Niels Bohr, Hendrik Kramers, and John C. Slater proposed the possibility that energy conservation is only true for large statistical ensembles and could be violated for small quantum systems. BKS theory also argued against the quantum nature of light. The Bothe-Geiger experiments helped disprove BKS theory, marking an end to old quantum theory, and inspiring the re-interpretation of the theory in terms of matrix mechanics by Werner Heisenberg.
The experiment used for the first time a coincidence method, thanks to the coincidence circuit developed by Bothe. Bothe received the Nobel Prize in Physics in 1954 for this development and successive experiments using this method.
Motivation
In 1923, Arthur Compton had shown experimentally that x-rays were scattered elastically by free electrons, in accordance to the conservation of energy. The scattered photon had a lower frequency than the incoming photon, according to the Planck–Einstein relation for the energy ( is Planck constant and is the angular frequency), while the remaining energy was transmitted to the recoil electron.
This discovery started a debate between those that believed that the energy was always conserved like Compton, Albert Einstein and Wolfgang Pauli, and those who believed it was only statistically valid. Bohr, Kramers and Slater published their BKS theory in February 1924 in Zeitschift fur Physik, arguing against energy conservation in individual atomic scattering events. They also considered that light could be treated classically without the need of the light quanta hypothesis of Einstein.
After finishing his doctoral degree under the supervision of Max Planck in 1913, Walther Bothe joined the radioactivity group in the Physikalisch-Technische Reichsanstalt in Charlottenburg, Berlin, to work with Hans Geiger, at that time head of the lab. Bothe studied Compton scattering with x-rays using a cloud chamber filled with hydrogen.
Shortly after the publication of the BKS theory, Hans and Geiger announced in the same journal an experiment proposal to test BKS theory.
Werner Heisenberg remained agnostic with respect to BKS theory. In a letter to Arnold Sommerfeld, he wrote:
Experiment
According to Compton scattering, if an incident photon with energy given by hits an electron, the recoil electron and the scattered photon would fly in opposite directions in the direction perpendicular to the trajectory of the incident photon.
For the experiment, a collimated x-ray beam is directed to a scattering material in a gap between two counters. The counters are placed in the line perpendicular to the beam. The two counters consist of an electron counter and a photon counter that are placed in opposite sides from the beam. Due to the minimal energy of the recoil electron, the electron detection essentially occurs at their scattering site. Thus the scattering volume must be situated within the electron counter. The whole setup was enclosed in a glass sphere filled with hydrogen at atmospheric pressure.
In Bothe–Geiger experiment, Geiger needle counters covered with thin platinum foil were used to detect scattered photons. A fraction of the photons produced a measurable electric current due to the photoelectric effect. The count detections were recorded photographically using silver bromide film, by the means of a string electrometers. The efficiency of the coincidence counting was of the order of 1 for 10 events. Bothe and Geiger observed 66 coincidences in 5 hours, of which 46 were attributed to false counts, with a statistical fluctuation of 1 in 400,000.
The measurements and data treatment took over a year. The overall experiment produced more than three kilometers of the just 1.5 centimeter-wide film that had to be analyzed manually. According to Bothe, the "film consumption however was so enormous that our laboratory with the film strips strung up for drying sometimes resembled an industrial laundry".
Any delay between the detection of the photon and the electron would be a hint of a violation of the conservation of energy. However a simultaneous detection indicated a confirmation of Compton's theory.
Results, reception and legacy
In April 1925, Bothe and Geiger reported that the photon and electron counters responded simultaneously, with a time resolution of 1 millisecond. Their result confirmed the quantum nature of light and was the first evidence against BKS theory. They argued "Our results are not in accord with Bohr's interpretation of the Compton effect ... it is recommended therefore to retain until further notice the picture of Compton and [Peter] Debye.... One must therefore probably assume that the light quantum concept possesses a high degree of validity as assumed in that theory."
Published in September of the same year, an experiment carried in parallel by Compton and Alfred W. Simon using a different technique, reached similar conclusions. The Compton–Simon experiment used cloud chamber techniques to track two different types of tracks: tracks of the recoil electron and tracks of the photoelectrons. Compton and Simon confirmed the relative angles between the tracks predicted by Compton scattering. Compton and Simon write: "the results do not appear to be reconcilable with the view of the statistical production of recoil and photo-electrons by Bohr, Kramers and Slater. They are, on the other hand, in direct support of the view that energy and momentum are conserved during the interaction between radiation and individual electrons."
The Bothe–Geiger experiment and the Compton–Simon experiment marked an end to the BKS theory. Kramers was skeptic at the beginning. In a letter to Bohr, Kramers said "I can unfortunately not survey how convincing the experiments of Bothe and Geiger actually are for the case of the Compton effect". Bohr however finished by accepting the results, in a letter to Ralph H. Fowler he wrote: "there is nothing else to do than to give our revolutionary efforts as honourable a funeral as possible".
Compton congratulated Bothe and Geiger for their results. Max von Laue said that "Physics was saved from being led astray". Science philosopher Karl Popper catalogued the result as an experimentum crucis.
In 1925 after the experiment, Bothe succeeded Geiger as the director of the lab.
The same year, Heisenberg would start to develop a new reinterpretation of quantum mechanics, based on matrix mechanics. In his 1927 paper on the uncertainty principle, he opposes the statistical interpretation of quantum mechanics, citing the Bothe–Geiger paper. Heisenberg writes to Pauli: "I argue with Bohr over the extent to which the relation p1q1~h has its origin in the wave-or the discontinuity aspect of quantum mechanics. Bohr emphasizes that in the gamma-ray microscope the diffraction of the waves is essential; I emphasize that the theory of light quanta and even the Geiger-Bothe experiments are essential."
Almost a decade later, Robert S. Shankland performed an experiment that allegedly showed some inconsistencies with photon scattering, resurfacing the idea of BKS theory. However it was later disproved by Robert Hofstadter and John A. Mcintyre with an experiment similar to the Bothe–Geiger experiment reducing the time resolution to 15 nanoseconds.
Further experiments were carried out by Bothe using his coincidence method. Geiger and Walther Müller further developed the Geiger–Müller tubes, that were used by Bothe and Werner Kolhörster experiment in 1929 to show that fast electrons detected in cloud chambers came from cosmic rays. In 1954, the Nobel Prize in Physics was split in two, half for Max Born for "for his fundamental research in quantum mechanics, especially for his statistical interpretation of the wavefunction"" and the other half for Bothe for his "for the coincidence method and his discoveries made therewith". Geiger had already died in 1945 so he was not eligible for a share of the prize.
Physics experiments
References
Experimental particle physics | Bothe–Geiger coincidence experiment | [
"Physics"
] | 1,716 | [
"Particle physics",
"Experimental physics",
"Physics experiments",
"Experimental particle physics"
] |
76,047,368 | https://en.wikipedia.org/wiki/Point-surjective%20morphism | In category theory, a point-surjective morphism is a morphism that "behaves" like surjections on the category of sets.
The notion of point-surjectivity is an important one in Lawvere's fixed-point theorem, and it first was introduced by William Lawvere in his original article.
Definition
Point-surjectivity
In a category with a terminal object , a morphism is said to be point-surjective if for every morphism , there exists a morphism such that .
Weak point-surjectivity
If is an exponential object of the form for some objects in , a weaker (but technically more cumbersome) notion of point-surjectivity can be defined.
A morphism is said to be weakly point-surjective if for every morphism there exists a morphism such that, for every morphism , we have
where denotes the product of two morphisms ( and ) and is the evaluation map in the category of morphisms of .
Equivalently, one could think of the morphism as the transpose of some other morphism . Then the isomorphism between the hom-sets allow us to say that is weakly point-surjective if and only if is weakly point-surjective.
Relation to surjective functions in Set
Set elements as morphisms from terminal objects
In the category of sets, morphisms are functions and the terminal objects are singletons. Therefore, a morphism is a function from a singleton to the set : since a function must specify a unique element in the codomain for every element in the domain, we have that is one specific element of . Therefore, each morphism can be thought of as a specific element of itself.
For this reason, morphisms can serve as a "generalization" of elements of a set, and are sometimes called global elements.
Surjective functions and point-surjectivity
With that correspondence, the definition of point-surjective morphisms closely resembles that of surjective functions. A function (morphism) is said to be surjective (point-surjective) if, for every element (for every morphism ), there exists an element (there exists a morphism ) such that ( ).
The notion of weak point-surjectivity also resembles this correspondence, if only one notices that the exponential object in the category of sets is nothing but the set of all functions .
References
Category theory
Morphisms | Point-surjective morphism | [
"Mathematics"
] | 526 | [
"Functions and mappings",
"Mathematical structures",
"Mathematical objects",
"Fields of abstract algebra",
"Category theory",
"Mathematical relations",
"Morphisms"
] |
76,047,945 | https://en.wikipedia.org/wiki/David%20W.%20Lewis%20%28mathematician%29 | David W. Lewis (21 February 1944 in Douglas, Isle of Man—20 August 2021 in Dublin) was a Manx mathematician known for his contributions to quadratic forms theory. He spent his entire career at University College Dublin (UCD), where he was head of the Department of Mathematics (now the School of Mathematics and Statistics) from 1999 until 2002. After his retirement in 2009 he remained research active for many years.
Education and career
Lewis attended Douglas High School where he developed an interest in physics and astronomy, and ultimately mathematics. He attended the University of Liverpool, and after completing his BSc degree in 1965 commenced doctoral studies in topology under the guidance of CTC (Terry) Wall. When his PhD funding ended in 1968, he started as assistant lecturer at the UCD Mathematics Department, while continuing the work on his doctoral thesis, shifting from topology to algebra and specifically to the area of quadratic and hermitian forms.
During his first decade of lecturing at UCD, he completed his PhD thesis, Hermitian Forms over Algebras with Involution, under the supervision of Professor Wall and was awarded a doctorate by the National University of Ireland in 1979. He received a DSc from NUI in 1992, and served as head of the Department of Mathematics there from 1999 until 2002.
He supervised 4 PhDs and authored one monograph.
Books
Selected papers
References
External links
The mathematics of David W. Lewis Jean-Pierre Tignol, Université catholique de Louvain, The Lewisfest, 23 July 2009
People from Douglas, Isle of Man
1944 births
2021 deaths
20th-century Manx people
20th-century British mathematicians
21st-century Manx people
21st-century British mathematicians
Algebraists
Topologists
Alumni of the University of Liverpool
Academics of University College Dublin
Alumni of the National University of Ireland | David W. Lewis (mathematician) | [
"Mathematics"
] | 364 | [
"Topologists",
"Topology",
"Algebra",
"Algebraists"
] |
76,048,229 | https://en.wikipedia.org/wiki/Reuteran | Reuteran, which is synthesized by reuteransucrase, is a complex α-glucan that is differentiated in part by the large amount of α(1-4) and α(1-6) linkages. The polysaccharide is made of repeating monosaccharide units of D-glucose. The glucose units are connected via alpha glyosidic bonds between the first carbon on one glucose to the fourth carbon on the next glucose molecule. Additional branching αlpha linkages occur between the sixth carbon of a glucose molecule and then the first carbon of the subsequent glucose molecule. These branches occur approximately every 5-7 glucose units.
Synthesis
Reuteran is synthesized by an extracellular enzyme called reuteransucrase often found in Lactobacillus reuteri which is part of the lactic acid bacteria family. Bacterial cells secrete reuteransucrase into the environment around them which then binds to sucrose and hydrolyze it into glucose and fructose. The glucose monomers are polymerized together in α(1-4) and α(1-6) glycosidic bonds. The fructose can be used for other metabolic purposes within the cell, or converted to glucose. Around 70% of the bonds formed are 1-4 linkages.
Uses
Reuteran has a low digestibility in the human digestive tract which causes it to act similar to an insoluble fiber in the human digestive tract. Similar to other exopolysaccharides produced by lactic acid bacteria it can be used in the food industry. It can be used as a thickening agent, or to add texture to food products.
References
Wikipedia Student Program
Polysaccharides | Reuteran | [
"Chemistry"
] | 361 | [
"Carbohydrates",
"Polysaccharides"
] |
76,048,956 | https://en.wikipedia.org/wiki/Vermeology | Vermeology (from Latin vermes, worms) is the field of biology dedicated to the study of worms. A person who studies vermeology is referred to as a vermeologist.
The umbrella term "vermeology" has fallen out of common use, as the animals known as worms belong to multiple phyla that are not closely related. Subfields of vermeology include nematology, the study of nematodes, oligochaetology (also called lumbricology), the study of earthworms, and helminthology, which focuses on parasitic worms, also known as helminths. The field of malacology was also historically included within vermeology.
Works
The final book that Charles Darwin published in his lifetime focused on bioturbation by earthworms.
References
Zoology
Branches of biology
Subfields of zoology
Invertebrates
Worms (obsolete taxon) | Vermeology | [
"Biology"
] | 188 | [
"Subfields of zoology",
"Animals",
"Invertebrates",
"Zoology",
"nan"
] |
76,049,179 | https://en.wikipedia.org/wiki/Sulfammox | Sulfate reduction coupled to ammonium oxidation, or sulfammox, is a novel multi-step microbial process especially pertinent to industrial wastewater treatment.
Microbial species associated with sulfammox include but are not limited to Anammoxoglobus sulfate, Bacillus benzoevorans, Candidatus_ Anammoxoglobus, Bacillus cereus SUD-1. This list includes species that may perform sulfammox alongside other microbes, though SUD-1 was shown to perform sulfammox when isolated in an experiment.
Application to wastewater treatment
Wastewater from industrial activities presents a danger to human and aquatic life as present compounds may exacerbate the eutrophication of water bodies, leading to toxic algal blooms, and may poison aquatic organisms and, by extent, humans. High levels of sulfate (SO42-) and ammonium (NH4+) are present in wastewater, contributing to its dangers and toxicity, and thus facilitating their removal via sulfammox may be important in protecting human and aquatic life. The microbial anaerobic oxidation of ammonium (anammox) has been cultivated at wastewater treatment center for years in order to remove NH4+, but the removal of SO42- has been typically treated as a separate problem requiring completely different microbial bioreactors – resulting in costly operations attempting to mitigate high SO42- and NH4+ separately. The opportunity to unify both processes into a single system – utilizing sulfammox alongside anammox – may thus be appealing as a cost-efficient alternative to removing both SO42- and NH4+ from wastewater.
One study found that “after 180 days” of facilitating sulfammox and anammox in landfill leachates, “the nitrogen and sulfate removal efficiencies of 95.7% and 24.3%, respectively, were obtained” with sulfammox accounting for “27.5% of total inorganic nitrogen removal” and anammox accounting for “65.6%”. Although sulfammox has been estimated to be less metabolically efficient than anammox, it also may consume less energy than other processes; sulfammox enhancement in a bioreactor saved “44%... in aeration energy consumption”.
Another study observed that excessively high SO42- and NH4+ – “NH4+-N was 181.62 mg·(L·d)−1, SO42--S was 323.18 mg·(L·d)−1” – was toxic to sulfammox microbes and slowed the removal of the compounds from a bioreactor. The study did reach similar removal efficiencies of NH4+ and SO42- as Zhang et al. 2023, with “94.80%” and “52.57%” removed respectively. The experiment also involved the addition of bicarbonate which may have competed with SO42- to oxidize NH4+ and impeded the analysis of nitrogen and sulfur-compound removal rates
Artificial neural networks may assist in measuring the efficiency of sulfammox across various wastewater treatment centers and conditions, leading to its future optimization in removing harmful SO42- and NH4+ from industrial wastewater.
History and possible redox background
Sulfammox was first observed by Fdz-Polanco et al. 2001 in industrial wastewater treatment centers utilizing anaerobic bioreactors and it was largely believed to be exclusive to such artificial environments. However, its presence has since been proposed and observed in natural anoxic environments – including marine sediments and anaerobic ocean waters
Though the mechanisms of sulfammox are not entirely clear, multiple studies have attempted to model the process in a series of chemical reactions. According to Liu et al. 2008, the following system of chemical reactions may represent the sulfammox pathway without organic carbon:
SO42- + NH4+ ←→ SO42- + NO2− + S + H2O (1)
NH4+ + NO2− ←→ N2 + 2H2O (2)
NH4+ + ½ SO42- ←→ ½ N2 + ½ S + 2H2O (3)
However, Bi et al. 2020 found that anammox microbes could not perform sulfammox alone under strict anaerobic conditions and that sulfammox was, rather, a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes. Specifically, Bi et al. 2020 postulated that facultatively aerobic ammonia-oxidizing bacteria, found living alongside anammox microbes and protecting them from oxygen leakage, could accomplish Equation (1) in the above system of equations representing sulfammox and provide nitrite to anammox microbes. Subsequent sulfate reduction was found to be attributed to sulfur-reducing bacteria.
Mohammed Madani et al. 2022, on the other hand, found that the SUD-1 strain of Bacillus cereus could perform sulfammox in isolation according to the model proposed by Liu et al. 2008.
Liu et al. 2021 delineates sulfammox reactions involving organic carbon and sulfides:
3SO42- + 8NH4+ ←→ 3HS− + 4N2 + 5H+ + 12H2O (4)
CH2O + 4NH4+ + 4SO42- ←→ 5CO2 + 2N2 + 4HS− + 11H2O (5)
Further models exist and multiple may partially or fully reflect present sulfammox processes both in artificial and natural environments.
Astrobiological ramifications
Both Europa and Enceladus – Jupiter’s and Saturn’s moons respectively – may have a water subsurface ocean beneath their icy surface with present ammonia and sulfate. The availability of these and other nutrients, including methane and potentially organics, have made them ideal candidates for plausible life outside of Earth. Considering certain sulfammox microbes’ preference for slightly alkaline environments (8), Enceladus’ alkaline subsurface ocean (8-11) may exhibit qualities more consistent with an environment capable of supporting sulfammox than Europa's potentially slightly acidic ocean. Extraterrestrial life is completely hypothetical, however, and many generations of work remain until humans may be capable of investigating the plausibility of life on Europa and Enceladus.
References
Sulfates
Ammonia | Sulfammox | [
"Chemistry"
] | 1,338 | [
"Sulfates",
"Salts"
] |
76,049,781 | https://en.wikipedia.org/wiki/List%20of%20exomoon%20candidates | , there have been no positive confirmations of satellites of extra-solar planets (exomoons); however, some evidence in favour of their existence has been produced.
Timeline
— It has been surmised that J1407b, a possibly planetary-mass object that eclipsed the star V1400 Centauri (aka. J1407) in 2007, may have a few moons based on gaps observed in its circumstellar disk or ring system. Later studies have since found that J1407b is most likely a free-floating sub-brown dwarf or rogue planet, possibly less than 6 Jupiter masses.
— The confirmed hot Jupiter planet WASP-12b may also possess a moon.
, — A candidate exomoon of a free-floating planet MOA-2011-BLG-262L, was announced, but due to degeneracies in the modelling of the microlensing event, the observations can also be explained as a Neptune-mass planet orbiting a low-mass red dwarf, a scenario the authors consider to be more likely. In 2024 the latter scenario was confirmed.
— researchers using the Hubble Space Telescope published observations of the candidate exomoon Kepler-1625b I, which suggest that the host planet is likely several Jupiter masses, while the exomoon may have a mass and radius similar to Neptune. The study concluded that the exomoon hypothesis is the simplest and best explanation for the available observations, though warned that it is difficult to assign a precise probability to its existence and nature.
— reanalysis concluded that the data was fit better by a planet-only model. According to this study, the discrepancy was an artifact of the data reduction, and Kepler-1625b I likely does not exist.
– A hypothesis involving potential transits of large exomoons being detached from their planets (see ploonet) was positted to explain the light flux-variations of the Tabby's Star, which were identified from the data collected by Kepler space telescope.
— A paper by Chris Fox and Paul Wiegert examined the Kepler dataset for indications of exomoons solely from transit timing variations. Eight candidate signals were found that were consistent with an exomoon, however the signals could also be explained by the presence of another planet. Fox and Wiegert's conclusion was more and higher quality transit timing data would be required to establish whether these are truly moons or not. David Kipping re-derived the timings of six of the eight targets (based on a pre-peer review version) and evaluated the TTV evidence as uncompelling. The same study finds that Kepler-1625b I remains an exomoon candidate.
— astronomers reported an habitable-zone 1.7 exomoon candidate transiting one of the components in the planetary-mass binary 2MASS J1119-1137AB.
— an exomoon candidate was reported around the planet Kepler-1708b, and because it is orbiting a planet at approximately 1.6 AU from a star that is slightly more luminous than the Sun, it too could be within the habitable zone. However, this candidate is based on limited observations (only two transits) and some consider the data to be non-convincing.
— another exomoon candidate was reported around the planet Kepler-1513b (KOI-3678.01). Unlike the previous giant exomoon candidates of Kepler-1625 and Kepler-1708, this exomoon would be terrestrial-mass, ranging from 0.76 Lunar masses to 0.34 Earth masses depending on the planet's mass and moon's orbital period.
— a follow-up study by the same team found that the observed TTVs are caused by a second planet in the system, and not by a moon.
— The exomoon candidate around Kepler-1625b was again challenged, along with the Kepler-1708b candidate. This study argues that the statistical significance of these exomoon candidates is lower than previously claimed (with false positive probabilities of 10.9% and 1.6%, respectively) and that true giant exomoons would have stronger evidence. Evidence for exomoon transits may be caused by stellar activity in the Kepler light curves. Kipping's team published a response arguing that these exomoon candidates remain possible.
— New measurements with the Very Large Telescope of the star WASP-49 gave more evidences favoring the presence of a possible volcanically active-moon around the hot Jupiter WASP-49b.
Table
References
Exomoon candidates
Exomoons | List of exomoon candidates | [
"Astronomy"
] | 945 | [
"Astronomy-related lists",
"Astronomical objects",
"Lists of astronomical objects"
] |
74,536,101 | https://en.wikipedia.org/wiki/Antimony%20nitride | Antimony nitride, also called antimony mononitride, is an inorganic compound with the chemical formula SbN. Containing only antimony and nitrogen, this binary nitride material is an interpnictogen. It is the antimony analog of phosphorus mononitride.
Antimony nitride forms when antimony trichloride dissolves in liquid ammonia.
It has been investigated as a transparent film that conducts electricity.
See also
Phosphorus mononitride
References
Nitrides
Antimony compounds | Antimony nitride | [
"Chemistry"
] | 107 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
74,536,110 | https://en.wikipedia.org/wiki/Hideyuki%20Matsumura | was a Japanese mathematician particularly known for his textbooks in commutative algebra. He received his Ph.D. in 1958 from Kyoto University under the advisory of mathematician Yasuo Akizuki.
References
External links
The Oberwolfach Photo Collection has photos of him.
1930 births
1995 deaths
20th-century Japanese mathematicians | Hideyuki Matsumura | [
"Mathematics"
] | 66 | [
"Algebra",
"Algebraists"
] |
74,536,335 | https://en.wikipedia.org/wiki/Perfect%20ideal | In commutative algebra, a perfect ideal is a proper ideal in a Noetherian ring such that its grade equals the projective dimension of the associated quotient ring.
A perfect ideal is unmixed.
For a regular local ring a prime ideal is perfect if and only if is Cohen-Macaulay.
The notion of perfect ideal was introduced in 1913 by Francis Sowerby Macaulay in connection to what nowadays is called a Cohen-Macaulay ring, but for which Macaulay did not have a name for yet. As Eisenbud and Gray point out, Macaulay's original definition of perfect ideal coincides with the modern definition when is a homogeneous ideal in a polynomial ring, but may differ otherwise. Macaulay used Hilbert functions to define his version of perfect ideals.
References
Ideals (ring theory)
Commutative algebra | Perfect ideal | [
"Mathematics"
] | 171 | [
"Fields of abstract algebra",
"Commutative algebra"
] |
74,536,549 | https://en.wikipedia.org/wiki/Grade%20%28ring%20theory%29 | In commutative and homological algebra, the grade of a finitely generated module over a Noetherian ring is a cohomological invariant defined by vanishing of Ext-modules
For an ideal the grade is defined via the quotient ring viewed as a module over
The grade is used to define perfect ideals. In general we have the inequality
where the projective dimension is another cohomological invariant.
The grade is tightly related to the depth, since
Under the same conditions on and as above, one also defines the -grade of as
This notion is tied to the existence of maximal -sequences contained in of length .
References
Ring theory
Homological algebra
Commutative algebra | Grade (ring theory) | [
"Mathematics"
] | 136 | [
"Mathematical structures",
"Ring theory",
"Fields of abstract algebra",
"Category theory",
"Commutative algebra",
"Homological algebra"
] |
74,536,896 | https://en.wikipedia.org/wiki/Project%20Thunderbird | Project Thunderbird was a 1967 United States Atomic Energy Commission (AEC) proposal to use nuclear explosives to prepare coalbeds to gasify coal in place underground in Wyoming. The project was proposed as a component of Project Plowshare, which sought ways to use nuclear devices in public works and industrial development projects. The project aimed to exploit deep coal deposits to gasify them in situ with controlled combustion in the rubble chimney resulting from a deep nuclear detonation. The project was to be located on the border of Johnson County and Campbell County, about west of Gillette, Wyoming, in the Powder River Basin.
While initial reports on the project were optimistic, subsequent analysis cast doubt on the project's viability, and the project was not pursued.
Proposal
In 1966-677, the U.S. Atomic Energy Commission was approached by Wyoming coal engineers Wold and Jenkins, of Casper, Wyoming, with the idea of extending Project Plowshare programs for the development of natural gas production using nuclear devices into coalbed areas. The project was received with interest, and was named Project Thunderbird. The Lawrence Radiation Laboratory (LRL), which administered many Plowshare programs, initiated a study to define a potential demonstration project in 1968.
The project was intended to investigate the possibility of enhancing the economic value of deeply-buried coalbeds in the Powder River Basin that could not easily be exploited by the strip mining methods used father east, where the beds approached the surface.
Project description
The project was intended to demonstrate techniques for creating a so-call "rubble chimney," a subterranean cavity, containing broken rubble and voids. Following the nuclear explosion that created the chimney, wells would be drilled to introduce oxygen and extract gas products. The pulverized coal would be ignited and fed oxygen under controlled conditions, converting the coal into combustible gas. In effect, the cavity would become a coking oven, driving off the volatile components of coal and leaving the residual carbon coke in the ground.
The project was proposed for deep coalbeds in the Fort Union-Wasatch Formation. The Roland coalbed, which was being surface mined at the Wyodak Mine to the east, lies at depths of or more at the Thunderbird project site, at thicknesses of up to .
Two possible project scopes were described. A 50-kiloton explosion was expected to create a chimney in radius and high, containing about of broken rock. About 25 percent of the contents of the cavity would be coal, which could produce the equivalent of about 1.5 million barrels of oil. A second proposal suggested a one-megaton explosion that was expected to create a chimney with a radius and a height of . This would contain seven times as much coal, and would fracture the coal beds for a greater distance beyond the chimney, with a further 10%-50% increase in gas yield. Gas from the wellhead would be processed by the Fischer-Tropsch process into gas and petroleum products. Existing gas and oil pipeline infrastructure would move the productsto market.
14 test borings were made on Wold and Jenkins leases. No other exploration has been documented, and the area has in subsequent years been extensively investigated and drilled for gas projects.
Outcome
Wold and Jenkins engineers viewed the project as potentially economically viable. A 1969 analysis by Gibbs & Hill, Inc. was less optimistic, advising the LRL that assumptions concerning development costs versus production did not yield a viable project. This opinion appears to have halted the project. No specific location for the test was identified.
References
Further reading
1968 in Wyoming
Thunderbird
Thunderbird
Thunderbird
Johnson County, Wyoming
Campbell County, Wyoming
Coal gasification technologies | Project Thunderbird | [
"Chemistry"
] | 746 | [
"Synthetic fuel technologies",
"Coal gasification technologies",
"Explosions",
"Peaceful nuclear explosions"
] |
74,536,949 | https://en.wikipedia.org/wiki/HD%20174430 | HD 174430, also designated as HR 7093 or rarely 32 G. Telescopii, is a solitary blue-hued star located in the southern constellation Telescopium near Kappa Telescopii. It has an apparent magnitude of 6.29, placing it near the limit for naked eye, even under ideal conditions. The object is located relatively far at a distance of 1,140 light-years based on Gaia DR3 parallax measurements, but it is drifitng closer with a heliocentric radial velocity of . At its current distance, HD 174430's brightness is diminished by 0.32 magnitudes due to interstellar extinction and it has an absolute magnitude of −1.80.
HD 174430 has a stellar classification of B3/5 III, indicating that it is an evolved B-type star with the characteristics of a B3 and B5 giant star. It has also been given a less evolved class of B6 V. It has 4.05 times the mass of the Sun and 5.72 times the radius of the Sun. It radiates 696 times the luminosity of the Sun from its photosphere at an effective temperature of . HD 174430 has a near solar metallicity of [Fe/H] = −0.01 and it is estimated to be 76 million years old.
References
B-type giants
Telescopium
Telescopii, 32
CD-52 08861
174430
092687
7093 | HD 174430 | [
"Astronomy"
] | 315 | [
"Telescopium",
"Constellations"
] |
74,537,750 | https://en.wikipedia.org/wiki/Thailand%20Tokamak-1 | Thailand Tokamak-1 (or TT-1) is a small research tokamak operated by the Thailand Institute of Nuclear Technology in Nakhon Nayok province, Thailand. The tokamak was built in collaboration with the Institute of Plasma Physics of the Chinese Academy of Sciences and features an upgraded design based on the HT-6M tokamak developed in 1984. The first successful test of the device occurred on 21 April 2023. TT-1 officially began operations on 25 July 2023 and became the first tokamak to operate in Southeast Asia.
References
Tokamaks
Nuclear technology in Thailand | Thailand Tokamak-1 | [
"Physics"
] | 124 | [
"Plasma physics stubs",
"Plasma physics"
] |
74,538,625 | https://en.wikipedia.org/wiki/Jean-Loup%20Delcroix | Jean-Loup Delcroix (1924–2003) was a French physicist, specializing in the physics of gases and plasmas.
Biography
Jean-Loup Delcroix received secondary education at Lycée Janson-de-Sailly in Paris and Lycée Champollion in Grenoble. He matriculated in 1944 at ENS Paris and graduated there in 1948 with outstanding rank in the agrégation in physics. He graduated in 1953 with a doctorate from the University of Paris. His thesis is entitled Étude des propriétés statiques des charges d'espace du type magnétron. Under the supervision of Yves Rocard, he participated in the construction and start-up of the linear accelerator at Orsay from 1952 until 1960. At Paris-Sud University he was a maître de conférences (MCF) from 1960 to 1965 and a professor from 1965 to 1990, when he retired as professor emeritus. In 1960 Delcroix formed Paris-Sud University's Laboratoire de Physique des Gaz et des Plasmas (LPGP), in association with the CNRS. He was the laboratory's director from 1960 to 1984. He made important contributions to the physics of gas discharges and low-temperature plasmas. During the early 1970s he led a research group on gas discharges with applications to gas laser physics.
At Paris-Sud University, Delcroix created in 1960 a graduate curriculum in plasma physics at the level of the diplôme d’études approfondies (DEA). His curriculum became a model at other French universities. His lectures on plasma physics formed the basis of three monographs originally published from 1959 to 1966. In 1961 with Jean-François Denisse, he published an important monograph on waves in plasmas. Delcroix, in collaboration with Abraham Bers (1930–2015), wrote a two-volume textbook entitled Physique des Plasmas, published in 1994.
From 1965 to 1976 Delcroix was the director of scientific research for the Direction des Recherches et Moyens d’Essai (D.R.M.E.), France's agency for development and coordination of military research. The D.R.M.E. was created in 1961 by Lucien Malavard (1910–1990). From 1978 to 1989 Delcroix was the Director General of the École supérieure d'électricité (Supélec). Under his directorship, Supélec expanded to three campuses and modernized its curriculum. From 1982 to 2003 he was France's representative to the Committee on Data of the International Science Council (CODATA). Beginning in 1975, Delacroix with several colleagues created and maintained GAPHYOR (GAz PHysique ORsay), a database and computerized retrieval system for atomic and molecular physics.
The French government appointed him Chevalier des Palmes académiques (1966), Chevalier de la Légion d'honneur (1969), Commandeur de l'ordre national du Mérite (1984), and Officier de la Legion d'honneur (1989).
He and his first wife had a son and two daughters. After divorce from his first wife, J.-L. Delcroix remarried and became the stepfather of one child. He was predeceased by his second wife.
Articles
Books
; translated into English:
; translated into English:
; translated into English:
with Abraham Bers: Physique des plasmas, EDP Sciences, 1994;
References
1924 births
2003 deaths
Plasma physicists
20th-century French physicists
École Normale Supérieure alumni
University of Paris alumni
Academic staff of Paris-Sud University
Officers of the Legion of Honour | Jean-Loup Delcroix | [
"Physics"
] | 768 | [
"Plasma physicists",
"Plasma physics"
] |
74,539,051 | https://en.wikipedia.org/wiki/Bleating%20tree%20frog | The bleating tree frog of Australia has been split into three distinct species:
Screaming tree frog (Litoria quiritatus), from northeastern Victoria to mid-coast New South Wales
Robust bleating tree frog (Litoria dentata sensu stricto), from northeastern New South Wales to the NSW/Queensland border
Slender bleating tree frog (Litoria balatus) from southeastern Queensland
Animals by common name
Amphibian common names
Frogs | Bleating tree frog | [
"Biology"
] | 92 | [
"Animals",
"Animals by common name"
] |
74,539,323 | https://en.wikipedia.org/wiki/Aaron%20Sadow | Aaron David Sadow is an American chemist.
Sadow earned a bachelor's of science degree in chemistry from Pennsylvania State University in 1997, and authored the honors thesis New Process for Synthesis of Polymers via Oxidative Carbonylation using Palladium (II) Catalysts under the direction of Ayusman Sen. Sadow completed his doctoral dissertation, Early Transition Metal Complexes in σ-Bond Metathesis: The Activation of Si–H, Si–C, and C–H Bonds, in 2003, advised by T. Don Tilley of the University of California, Berkeley, then pursued postdoctoral research at ETH Zurich. Sadow joined the Iowa State University faculty in August 2005. In 2016, he was promoted to a full professorship. Sadow is a founding researcher for the Program on Plastics, Ecosystems, and Public Health, established in 2019 and based at the Institute for Sustainability and Energy at Northwestern University. Sadow was named the director of Ames National Laboratory's Institute for Cooperative Upcycling of Plastics in 2020, one of the Energy Frontier Research Centers established that year by the United States Department of Energy. Sadow is a 2022 fellow of the American Association for the Advancement of Science.
Sadow's research includes inorganic and organometallic chemistry, particularly catalysis.
References
Pennsylvania State University alumni
University of California, Berkeley alumni
American expatriates in Switzerland
American inorganic chemists
Year of birth missing (living people)
Living people
Iowa State University faculty
Fellows of the American Association for the Advancement of Science
21st-century American chemists | Aaron Sadow | [
"Chemistry"
] | 315 | [
"American inorganic chemists",
"Inorganic chemists"
] |
74,540,613 | https://en.wikipedia.org/wiki/Germ%C3%A1n%20Sierra | Germán Sierra is a Spanish theoretical physicist, author, and academic. He is Professor of Research at the Institute of Theoretical Physics Autonomous University of Madrid-Spanish National Research Council.
Sierra's research interests span the field of physics and mathematical physics, focusing particularly on condensed matter physics, conformal field theory, exactly solved models, quantum information and computation and number theory. He has authored two books entitled, Quantum Groups in Two-dimensional Physics and Quantum electron liquids and hight-Tc Superconductivity and also has published over 200 articles.
Sierra serves as an Editor of the Journal of Statistical Mechanics: Theory and Experiment, Journal of High Energy Physics and Nuclear Physics B.
Education
Sierra earned his Baccalaureate degree in physics from the University of Complutense de Madrid in 1978, followed by a Ph.D. in physics from the same university in 1981. He then completed his Postdoc from the l’École Normale Supérieure in Paris in 1983.
Career
Following his Postdoc, Sierra began his academic career as a Titular Professor at the University of Complutense de Madrid in 1984, a position he held for
three years. In 1987 he was appointed as a research fellow at the European Council for Nuclear Research (CERN) in Geneva and as a Scientific Researcher at Spanish National Research Council in 1989. Since 2005, he has been serving as a Full Professor of Physics at the Spanish National Research Council in Spain. He has held visiting appointments at Erwin Schrödinger Institute, Kavli Institute for Theoretical Physics, Max Planck Institute for Quantum Optics, University of Sao Paulo, Princeton University, Isaac Newton Institute for Mathematical Sciences, Stony Brook University, and University of Innsbruck
From 2014 to 2017, he was a Member of the International Union of Pure and Applied Physics (IUPAP), Panel C18 on Mathematical Physics.
Research
Sierra's research focuses on quantum physics with a particular emphasis on supergravity, quantum groups, quantum many body systems, integrable models. His research has contributed to the understanding of supergravity theories, conformal field theory, superconductivity spin chains and ladders, Richardson-Gaudin model, physical models of the Riemann Zeros, quantum Hall states, inhomogeneous spin chains, infinite matrix product states, The Prime State, quantum computation, and quantum games.
Supergravity
During his early research career, Sierra worked in the area of supergravity to construct and classify the N = 2 Maxwell-Einstein Supergravity theories (MESGT). His work involved an investigation of the algebraic and geometric structures underlying these theories, as well as their compact and non-compact gaugings. In collaboration with M. Gunaydin and P.K. Townsend, he derived the magic square of Freudenthal, Rozenfeld, and Tits by utilizing the geometric principles found in a specific group of N=2 Maxwell-Einstein supergravity theories.
Quantum groups
In 1990, Sierra's research diverted toward the construction, interpretation, and application of quantum groups in the context of conformal field theories, two-dimensional physics, and renormalization groups. He demonstrated that the representation theory of the q-deformation of SU(2) offers solutions to the polynomial equations formulated by Moore and Seiberg for rational conformal field theories, as long as q is a root of unity. Together with Cesar Gomez, he defined the representation spaces of the quantum group in terms of screened vertex operators and interpreted the number of screening operators as the genuine quantum group number. He introduced a spin chain Hamiltonian that possesses integrability and invariance under 14 (sI(2)) transformations within nilpotent irreducible representations when r3 = 1. Additionally, he proved that the elliptic R-matrix of the eight vertex free fermion model is the intertwiner R-matrix of a quantum deformed Clifford-Hopf algebra that the elliptic R-matrix of the eight-vertex free fermion model corresponds to the intertwiner R-matrix of a quantum deformed Clifford-Hopf algebra. In his work, he also presented a new mathematical structure entitled, graph quantum group which merges the tower of algebras associated with a graph G with the structure of a Hopf algebra {\cal A}. Furthermore, he explored spin-anisotropy commensurable chains, a class of 2D integrable models, and described their mathematics using quantum groups with the deformation parameter as an Nth root of unity. Moreover, alongside Miguel A. Martín-Delgado, he employed real space renormalization group (RG) methods to examine the interplay between two different variants of quantum groups, exploring their relationship.
Spin chains and ladders
In 1996, Sierra started working in condensed matter physics, more concretely on spin chains, spin ladders and high-Tc superconductors. He generalized Haldane's conjecture from spin chains to spin ladders using the O(3) non-linear sigma model. He also investigated phase transitions in staggered spin ladders and three-legged antiferromagnetic ladders. In addition, he applied the variational matrix product ansatz to determine the ground state of several ladder systems. In a joint study with J. Dukelsky, M.A. Martín-Delgado and T. Nishino, he showed that the latter method is equivalent to the DMRG method introduced by S. R. White in 1992. Working together with Martín-Delgado in 1998, he proposed an extension of the variational matrix product ansatzs to two dimensions. In 2004, F. Verstraete and J.I. Cirac rediscovered the latter ansatz using quantum information techniques, designating it as PEPS.
Richardson-Gaudin models
In 1999, Sierra in collaboration with J. Dukelsky applied the DMRG method to the pairing model that describes ultrasmall superconducting grains, confirming the exact solution of the pairing model obtained by Richardson and Sherman in 1963–64. Shortly after its application, a close relationship was revealed between Richardson's solution and another set of exactly solvable models called the Gaudin magnets, collectively known as Richardson-Gaudin models. Several subsequent applications involved studying the effect of level statistics in nanograins, the connection with conformal field theory and Chern-Simons theory, as well as exploring the implications with mean-field solutions and p-wave symmetry.
Russian doll renormalization group
In 2003–04, Sierra, in conjunction with A. LeClair and J.M. Román, introduced multiple models exhibiting a Russian doll renormalization group flow, featuring a cyclic nature instead of converging to a fixed point. Among them was a BCS model with pairing scattering phases that break time-reversal symmetry, which was later demonstrated to be solvable using the algebraic Bethe ansatz. Moreover, they put forward two scattering S-matrices exhibiting a cyclic renormalization group (RG) structure, which is related to both the cycle regime of the Kosterlitz-Thouless flow and an analytic extension of the massive sine-Gordon S matrix.
Physical models of the Riemann zeros
In 2005, Sierra presented a Russian doll model of superconductivity whose spectrum contains the average Riemann zeros as missing spectral lines, and this model is connected to the xp Hamiltonian of Berry, Keating, and Connes. In addition to proposing several variations of the xp model, he collaborated with C. E. Creffield to propose a different physical realization of the Riemann zeros using periodically driven cold atoms; this idea was eventually experimentally achieved in 2021 using trapped ions.
Entanglement in quantum hall states
In 2009, Sierra and I. D. Rodríguez evaluated the entanglement entropy for integer quantum Hall states, involving the computation of the entanglement spectrum, proposed by Li and Haldane to identify topological order in non-abelian quantum Hall states.
Entanglement in conformal field theory
Sierra computed with F. C. Alcaraz and M. Ibáñez the entanglement properties of the low-lying excitations in conformal field theory in 2011 and found several applications to condensed matter systems, holography, and systems with boundaries. Furthermore, he independently discovered with J. C. Xavier and F. C Alcaraz the property of "entanglement equipartition" in conformal systems with U(1) symmetry, where the entanglement entropy is equally distributed in different charge sectors and this finding holds for more general systems up to corrections, separate from the works.
Entanglement in inhomogeneous spin chains
In 2014, Sierra, along with J. Rodríguez-Laguna and G. Ramírez, introduced an inhomogeneous spin chain model called rainbow chain that exhibits a maximal violation of the area law of entanglement entropy, in stark contrast to the behavior observed in homogeneous chains. The rainbow chain model, earlier proposed by J. I. Latorre in a separate joint work, was examined using conformal field theory techniques and was found to support symmetry-protected phases.
Infinite matrix product states and conformal field theory
In 2010, Sierra proposed a variational ansatz for the ground state of the XXZ spin chain using the chiral vertex operators of a CFT to describe the critical region of this model, resulting in a matrix product state with an infinite bond dimension to capture logarithmic entanglement entropy. The ansatz also replicated the Haldane-Shastry wave function for the XXX spin chain, notably matching a conformal block of the WZW model SU(2) at level k=1, and was later extended to any level k jointly with A. E. B. Nielsen and J. Ignacio Cirac. In two spatial dimensions, the CFT wave function demonstrated a bosonic Laughlin spin liquid state on a lattice, that was experimentally realized using optical lattices. This method was extended to other bosonic and fermionic Laughlin states, WZW model SU(N)_1, etc. The CFT wave functions described earlier were derived as tensor network states where the individual tensors are functionals of fields which allowed the analysis of the symmetries of the field tensor network states.
The prime state
Along with J. I. Latorre, Sierra proposed a quantum circuit that creates a pure state corresponding to the quantum superposition of all prime numbers less than 2^n, where n is the number of qubits of the register. They showed the construction of the Prime state using the Gover algorithm that combined with the quantum counting algorithm allows for a verification of the Riemann hypothesis for numbers far beyond the reach of any classical computer. Moreover, the Prime state turned out to be highly entangled with an entanglement spectrum intimately related to the Hardy-Littlewood constants for the pairwise distribution of primes.
Quantum computation
Through collaborative research efforts, Sierra implemented multiple quantum algorithms on the newly launched IBM quantum computers and introduced a quantum circuit capable of generating the Bethe eigenstates for the XXZ Hamiltonian. Additionally, he proposed a simple mitigation strategy for a systematic gate error in IBMQ quantum computers and demonstrated the implementation of data-driven error mitigation techniques to simulate quench dynamics on a digital quantum computer.
Quantum games
In 2022, Sierra, together with A. Bera and S. Singha Roy, demonstrated a connection between the ground state of a topological Hamiltonian and the optimal strategy in a causal order game, where the maximum violation of the classical bound is associated with a second-order quantum phase transition. Furthermore, working in conjunction with D. Centeno led to the development of several quantum versions of the Morra game, known as Chinos in Spain.
Bibliography
Books
Quantum Electron Liquids and High-Tc Superconductivity (1995)
Quantum Groups in Two-dimensional Physics (2011)
Selected articles
Günaydin, M, Sierra, G & Townsend, PK (1984). The geometry of N=2 Maxwell-Einstein supergravity and Jordan algebras. Nuclear Physics B 242 (1), 244–268.
Alvarez-Gaume, L, Gomez, C. & Sierra, G (1989). Quantum group interpretation of some conformal field theories. Physics Letters B 220 (1–2), 142–152.
Dukelsky, J., Martín-Delgado, M. A., Nishino, T., & Sierra, G. (1998). Equivalence of the variational matrix product method and the density matrix renormalization group applied to spin chains. Europhysics letters, 43(4), 457.
Dukelsky, J., Pittel, S., & Sierra, G. (2004). Colloquium: Exactly solvable Richardson-Gaudin models for many-body quantum systems. Reviews of modern physics, 76(3), 643.
Cirac, JI & Sierra, G (2010). Infinite matrix product states, conformal field theory and the Haldane-Shastry model. Physical Review B 81 (10), 104431.
Alcaraz, F. C., Berganza, M. I., & Sierra, G. (2011). Entanglement of low-energy excitations in Conformal Field Theory. Physical Review Letters, 106(20), 201601.
Latorre, J. I. & Sierra, G (2014), Quantum Computation of Prime Number Functions, Quantum Information and Computation, Vol. 14, 0577.
Ramírez, G, Rodríguez-Laguna, J & Sierra, G. (2015). Entanglement over the rainbow. Journal of Statistical Mechanics: Theory and Experiment 2015 (6), P06002.
Xavier, J. C., Alcaraz, F. C., & Sierra, G. (2018). Equipartition of the entanglement entropy. Physical Review B, 98(4), 041106.
Sierra, G (2019). The Riemann zeros as spectrum and the Riemann hypothesis. Symmetry 11 (4), 494.
References
Theoretical physicists
Complutense University of Madrid alumni
Quantum physicists
Condensed matter physicists
1955 births
Living people
Academic staff of the Complutense University of Madrid | Germán Sierra | [
"Physics",
"Materials_science"
] | 2,952 | [
"Condensed matter physicists",
"Theoretical physics",
"Quantum physicists",
"Quantum mechanics",
"Condensed matter physics",
"Theoretical physicists"
] |
74,541,237 | https://en.wikipedia.org/wiki/Travel%20alarm%20clock | A travel clock, travel alarm clock and in some cases pouch alarm clock, is an alarm clock whose primary characteristic is that it must have a size, design, and weight that make it easily transportable during a trip, so it is usually contained in a box or case. In the case of an alarm clock, the box must let the acoustic signal pass through to wake up from sleep at the set time or time and date.
History
For a long time, watches were luxury items. Most of the population's sleep ended when it got light, or the rooster crowed. The night watchman awakened the few who had to rise before dawn. However, watches with an additional alarm function have been around for as long as classic watches, that is, since the 14th century. In Dante's Divine Comedy of 1320, there is a very precise description of a clock equipped with a bell mechanism.
Descriptions of water clocks have been preserved from antiquity, where the water level in a vessel indicated the time. Most had floats inserted, which activated bells or figures through a lever when it reached a certain filling level. In 12th-century monasteries, alarm clocks with bell signals reminded people to observe prayer times. However, these "clocks" have not survived to this day, except in the form of manuscripts.
The oldest surviving alarm clocks are the wall clocks that signaled the tower guards to ring the church bells. These so-called tower clocks date from the 15th and 16th centuries. .
Renaissance and Baroque
With the invention of the flywheel and the spring as an energy reservoir, alarm clocks, including an alarm function, became portable. They were popular luxury accessories for wealthy and noble citizens. However, they were not yet to be used on the journey but only in the night barracks or at the place of arrival.
For traveling by carriage or horseback, from the 17th to the 19th centuries, a little chunky pocket watches with alarms. They indicate the intended use in their name, "carriage clocks". These carriage clocks kept reasonably accurate time despite the potholes and rocking of bumpy roads.
With the turn of the modern era, the first travel alarm clocks appeared, the "officer's alarm clocks", mainly used to wake up officers. These portable watches were valued as travel companions in wealthy circles. Therefore, they were also called "Pendule de Voyage".
From the 1860s and 1870s, the “Paris alarm clock”, initially produced in France, was very compact. Unlike its American counterpart, it still had a clockwork mechanism with solid plates and gears. This alarm clock with a short pendulum was aimed more at lower middle-class households.
Industrial era
A finals del segle XIX, els treballadors i empleats havien d'arribar a temps a la feina. Durant molt de temps, els robustos rellotges de fusta dels tallers i fàbriques de la Selva Negra van ser la forma més econòmica de despertar-se de manera fiable. Els rellotges de taula de fabricació industrial amb funció d'alarma basats en el model americà dels cottage clocks eren una mica més cars.
At the beginning of the 20th century, the travel alarm clock was adapted to the taste of the time. The attached bell disappeared, the back wall serving as a sounding board. The strong colors gave the alarm clocks a friendly look. Countless shapes were created so that everyone could find "their" alarm clock. The alarm movement was also improved: there were alarm clocks with a repeater, inflated tone, or soft movement. Thanks to railroads and automobiles, the alarm clock was often used on trips. There are travel alarm clocks with a special case for this purpose.
A wristband travel alarm clock was patented in 1908 by the Eterna company. The best-known wristband-type travel alarm clock models were Jaeger-LeCoultre's Memovox in 1950 and Pierce's Duofon in 1955. While the dwellings adapted to the contemporary taste of the society, the technology remained the same for a long time. Only with electronics did the construction of travel alarm clock mechanisms change. The quartz revolution and clock radio technology ensured that high-precision travel alarm clocks were soon available for little money.
Since the late 20th century and early 21st century, travel alarm clocks have been gradually replaced as they are incorporated as an additional feature in many devices that contain a clock, such as mobile phones or smartphones with built-in alarm systems and the travel alarm was relegated to oblivion.
Pouch travel clock
With the invention of portable clocks in the 16th century, the travel alarm clock became mobile thanks to the spring as an energy accumulator and the steering wheel. In the 1920s, travel alarm clocks were mass-produced with increasing mobility. At first, resembling the travel alarm clocks of earlier eras, they were covered in an elegant case that protected the watch while traveling. The watch was removed from its protective case at night and placed on the bedside table. Later, a hinge attached the machinery to the pouch-like sheath. So, the case protected the alarm clock and was also its support.
Digital screen
Digital travel alarm clocks have an electronic clock mechanism that can display various data through the screen. This makes it possible to integrate numerous additional functions that would be difficult or impossible to implement in mechanical or electromechanical alarm clocks. In addition to the usual tasks of digital clocks, in some models, additional alarms can be preset depending on the day of the week or an automatic alarm clock when the outside temperature drops below a specified value.
Repeat button
The repeat is used to briefly interrupt the alarm clock. The alarm sounds again after a certain period, depending on the device, after five or ten minutes. This interruption can be repeated as many times as you want. Finally, the alarm can only be turned off by deactivating the alarm button. The snooze button is generally designed to be easy to find in the dark. In addition to this button, Braun introduced several models in the 1980s whose alarm could also be stopped by "voice control"
Gallery
Manufacturers of pocket travel clocks
Europa, Micro (watches), Peter, Schatz
References
Bibliography
Emmanuelle Cournarie, La mecànica du geste, tros siècles d'histoire horlogère à Saint-Nicolas d'Aliermont, Édition PTC-Les Falaises, 2011 (francès)
Lolita Delesque i Marianne Lombardi, Armand Couaillet, horloger et inventeur de génie, Musée de l'horlogerie, juny de 2013, 44p (francès)
External links
Clocks
Travel | Travel alarm clock | [
"Physics",
"Technology",
"Engineering"
] | 1,374 | [
"Physical systems",
"Machines",
"Clocks",
"Measuring instruments"
] |
74,543,750 | https://en.wikipedia.org/wiki/Cosmological%20phase%20transition | A cosmological phase transition is a physical process, whereby the overall state of matter changes together across the whole universe. The success of the Big Bang model led researchers to conjecture possible cosmological phase transitions taking place in the very early universe, at a time when it was much hotter and denser than today.
Any cosmological phase transition may have left signals which are observable today, even if it took place in the first moments after the Big Bang, when the universe was opaque to light.
Cosmological first-order phase transitions
Phase transitions can be categorised by their order. Transitions which are first order proceed via bubble nucleation and release latent heat as the bubbles expand.
As the universe cooled after the hot Big Bang, such a phase transition would have released huge amounts of energy, both as heat and as the kinetic energy of growing bubbles. In a strongly first-order phase transition, the bubble walls may even grow at near the speed of light. This, in turn, would lead to the production of a stochastic background of gravitational waves. Experiments such as NANOGrav and LISA may be sensitive to this signal.
Shown below are two snapshots from simulations of the evolution of a first-order cosmological phase transition. Bubbles first nucleate, then expand and collide, eventually converting the universe from one phase to another.
Examples
The Standard Model of particle physics contains three fundamental forces, the electromagnetic force, the weak force and the strong force. Shortly after the Big Bang, the extremely high temperatures may have modified the character of these forces. While these three forces act differently today, it has been conjectured that they may have been unified in the high temperatures of the early universe.
Strong force phase transition
Today the strong force binds together quarks into protons and neutrons, in a phenomenon known as color confinement. However, at sufficiently high temperatures, protons and neutrons disassociate into free quarks. The strong force phase transition marks the end of the quark epoch. Studies of this transition based on lattice QCD have demonstrated that it would have taken place at a temperature of approximately 155 MeV, and would have been a smooth crossover transition.
This conclusion assumes the simplest scenario at the time of the transition, and first- or second-order transitions are possible in the presence of a quark, baryon or neutrino chemical potential, or strong magnetic fields.
The different possible phase transition types are summarised by the strong force phase diagram.
Electroweak phase transition
The electroweak phase transition marks the moment when the Higgs mechanism first activated, ending the electroweak epoch.
Just as for the strong force, lattice studies of the electroweak model have found the transition to be a smooth crossover, taking place at
The conclusion that the transition is a crossover assumes the minimal scenario, and is modified by the presence of additional fields or particles. Particle physics models which account for dark matter or which lead to successful baryogenesis may predict a strongly first-order electroweak phase transition.
Phase transitions beyond the Standard Model
If the three forces of the Standard Model are unified in a Grand Unified Theory, then there would have been a cosmological phase transition at even higher temperatures, corresponding to the moment when the forces first separated out. Cosmological phase transitions may also have taken place in a dark or hidden sector, amongst particles and fields that are only very weakly coupled to visible matter.
See also
Timeline of the early universe
Chronology of the universe
Phase transition
Physics beyond the Standard Model
References
Physical cosmology
Big Bang
Concepts in astronomy
Astronomical events
Scientific models
Particle physics | Cosmological phase transition | [
"Physics",
"Astronomy"
] | 739 | [
"Cosmogony",
"Astronomical sub-disciplines",
"Concepts in astronomy",
"Big Bang",
"Astronomical events",
"Theoretical physics",
"Astrophysics",
"Particle physics",
"Physical cosmology"
] |
74,544,407 | https://en.wikipedia.org/wiki/Ivano%20Bertini | Ivano Bertini (December 6, 1940 – July 7, 2012) was an Italian chemist recognized for his significant contributions in the field of bioinorganic chemistry, particularly in NMR spectroscopy of metalloproteins.
Early life and education
Bertini was born in Pisa, Italy, in 1940. He completed his graduation in 1964 at the University of Florence in inorganic chemistry, under the guidance of Luigi Sacconi. After graduation, he became Sacconi's assistant and started his research in inorganic physical chemistry and isomerism in coordination compounds. He had his first trips abroad to the Zurich Polytechnic in 1965 and Princeton University, where he began his studies of bioinorganic chemistry using NMR.
Career
In 1975, Bertini became a full professor of chemistry at the Faculty of Pharmacy of the University of Florence, and in 1981, at the Faculty of Mathematical, Physical and Natural Sciences. He founded the European Magnetic Resonance Center (CERM), based at the Scientific Campus of Sesto Fiorentino, in 1999.
His research on the structure of metalloproteins resulted in a significant number of publications, earning him international recognition. He received honorary degrees in chemistry from the Universities of Stockholm (1998) and Ioannina (2002), and in biology from the University of Siena (2003). In addition to other international awards, he was a member of the Academia Europaea and the National Lincei Academy.
He also served on the editorial or advisory boards of over 20 journals spanning chemistry, biochemistry, and inorganic chemistry.
His later studies made it possible to identify through NMR spectrometry a fingerprint corresponding to the metabolome in the blood and urine specific to each human being, a discovery that could have significant implications in medicine.
Death and legacy
Bertini passed away in 2012 in Florence.
He authored over 650 research papers and published over 150 protein structures.
Works
References
External links
Obituary in ChemViews
20th-century Italian chemists
University of Florence alumni
Academic staff of the University of Florence
Bioinorganic chemists
Members of the Lincean Academy
Members of Academia Europaea
People from Pisa
1940 births
2012 deaths
Bijvoet Medal recipients | Ivano Bertini | [
"Chemistry"
] | 443 | [
"Bioinorganic chemistry",
"Bioinorganic chemists"
] |
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