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66,669,731 | https://en.wikipedia.org/wiki/Antrodiella%20citrinella | Antrodiella citrinella is a species of fungus belonging to the family Phanerochaetaceae.
It is native to Europe.
References
Phanerochaetaceae
Fungus species | Antrodiella citrinella | [
"Biology"
] | 41 | [
"Fungi",
"Fungus species"
] |
66,671,811 | https://en.wikipedia.org/wiki/Dravidian%20numerals | Dravidian numerals are a numeral system that originated in ancient India and remained the usual way of writing numbers throughout Dravidian-speaking regions in South Asia. Numbers in this system are represented by combinations of letters from the various Indian scripts. In modern usage it has been replaced by Hindu-Arabic numeral systems.
References
Dravidian | Dravidian numerals | [
"Mathematics"
] | 72 | [
"Numeral systems",
"Numerals"
] |
66,672,615 | https://en.wikipedia.org/wiki/Mars%20Guy%20Fontana | Mars Guy Fontana was a corrosion engineer, professor of Metallurgical Engineering at Ohio State University. He was born April 6, 1910, in Iron Mountain, Michigan, and died February 29, 1988.
Education and other work
Mars Guy Fontana graduated with a Bachelor of Science followed by a Master of Science and then awarded a Doctor of Philosophy in the field of metallurgical engineering from the University of Michigan. He was known as a researcher/engineer who added to the field of knowledge in the fairly specialized area of corrosion and its various applications in engineering – corrosion engineering. As well as writing numerous papers he wrote the textbook Corrosion Engineering which was first published in 1967 ; there have been a number of updated editions since then. This book has been used as the primary textbook and recommended reading for at least one highly ranked University masters degree course. In his lifetime he wrote many papers in various scientific and engineering journals/periodicals. He also authored Corrosion: A Compilation.
In the late 1940s, he was given the chair in the Corrosion Center at Ohio State University. At the time it was the largest university corrosion research department in the United States. He combined the disciplines of engineering design, Material Science and Corrosion so they could be viewed together.
His contribution at the university was of such significance that he has a building named after him, the Fontana Laboratories. He also has a professorship named after him.
See also
Herbert H. Uhlig
Ulick Richardson Evans
Melvin Romanoff
Michael Faraday
Marcel Pourbaix
References
External links
Ohio State University website
AIME Website
1910 births
1988 deaths
Corrosion
University of Michigan College of Engineering alumni
Metallurgy | Mars Guy Fontana | [
"Chemistry",
"Materials_science",
"Engineering"
] | 325 | [
"Metallurgy",
"Materials science",
"Corrosion",
"Electrochemistry",
"nan",
"Materials degradation"
] |
66,672,901 | https://en.wikipedia.org/wiki/Abrothallus%20parmeliarum | Abrothallus parmeliarum is a species of lichenicolous fungus. It grows on the thallus and apothecia (fruiting bodies) of Parmelia species. The fungus was first described scientifically by the Norwegian botanist Søren Christian Sommerfelt in 1826. In 2018, a proposal was made to conserve the name Lecidea parmeliarum (later Abrothallus parmeliarum), against Endocarpon parasiticum, an older basionym dating from 1814. The conservation was recommended in 2023 by the Nomenclature Committee for Fungi due to the widespread use and recognition of Abrothallus parmeliarum as a common lichenicolous fungus, despite the priority of the lesser-used Endocarpon parasiticum. This action was supported to preserve the nomenclatural stability of what is considered the best-known species name among lichenicolous fungi.
References
parmeliarum
Fungi described in 1826
Lichenicolous fungi
Fungus species | Abrothallus parmeliarum | [
"Biology"
] | 209 | [
"Fungi",
"Fungus species"
] |
73,961,995 | https://en.wikipedia.org/wiki/Selenite%20sulfate | Selenite sulfates are mixed anion compounds containing both selenite (SeO32−) and sulfate (SO42−) anions.
They have transparent crystals that may be coloured by cations. Selenite sulfate minerals are known including pauladamsite and munakataite.
List
References
Sulfates
Selenites
Mixed anion compounds | Selenite sulfate | [
"Physics",
"Chemistry"
] | 73 | [
"Matter",
"Mixed anion compounds",
"Sulfates",
"Salts",
"Ions"
] |
73,962,054 | https://en.wikipedia.org/wiki/Trehalosamine | Trehalosamines are amino sugars in which a hydroxyl group of trehalose is replaced with an amino group. While 2-, 3-, and 4-trehalosamine derived from actinomycetes have been reported as natural compounds, 6-trehalosamine has been reported as a synthetic compound. They have weak antimicrobial activity and could be considered as a class of aminoglycoside antibiotics. The properties and functions of 4-trehalosamine have been well investigated as follows.
Protective activity
As "a trehalose possessing an amino group", trehalosamine shares many properties and characteristics in common with trehalose; in addition, unique functions due to the presence of an amino group are also suggested. Trehalose is used as a protective agent for starch, protein, cells, or tissues due to its non-reducing sugar moiety having lower non-specific reactivity than reducing sugars and high moisturizing and protective activities. In many cases, 4-trehalosamine exhibits these protective activities either comparable to or marginally higher than those of trehalose. In addition, 4-trehalosamine exhibits a strong pH buffering activity near neutrality, while trehalose does not have such ability. Therefore, it is expected to be added to foods and industrial products as a trehalose-type moisturizing and protective agent with pH buffering ability.
Effects on living organisms
Trehalose is known to exhibit autophagy-inducing activity, anti-inflammatory activity, molecular chaperone activity, or antioxidant activity in a broad sense in vivo. It is being studied for use as a treatment for neurodegenerative diseases and lifestyle-related diseases, as a medication, supplement, or as a prebiotic. However, as it is hydrolyzed in the body by trehalase, a trehalose-degrading enzyme, its physiological effect is limited. There is also concern that blood glucose levels may rise due to the generation of glucose as the degradation product. But, 4-trehalosamine is not degraded by human trehalase, and it has been confirmed in experiments with mice that it is non-toxic and does not raise blood sugar levels. For this reason, 4-trehalosamine is also attracting attention as a substitute for trehalose in these applications.
As a starting material for synthesis of trehalose derivatives
Generally, saccharides have multiple hydroxyl groups in the molecule, and to systematically synthesize specific derivatives, complicated protocols such as repeated protection and deprotection are required. Although it is limited to the amino group site, various derivatives can be synthesized relatively easily by utilizing the reactivity different from that of the hydroxyl group of trehalosamine. Low-molecular-weight derivatives such as azide, surfactant IMCTA-C14, fluorescent or biotin-labeled derivatives have been developed so far, and application to the development of polymeric compounds containing periodic trehalose structures is also expected.
References
Amino sugars
Disaccharides | Trehalosamine | [
"Chemistry"
] | 637 | [
"Amino sugars",
"Carbohydrates"
] |
73,963,628 | https://en.wikipedia.org/wiki/Sqlmap | sqlmap is a software utility for automated discovering of SQL injection vulnerabilities in web applications.
Usage
The tool was used in the 2015 data breach of TalkTalk. In 2016, the Illinois Board of Election was breached using the tool, combined with Acunetix and DirBuster.
References
External links
Computer security software
Free security software | Sqlmap | [
"Engineering"
] | 71 | [
"Cybersecurity engineering",
"Computer security software"
] |
73,963,722 | https://en.wikipedia.org/wiki/ARM%20Cortex-A520 | The ARM Cortex-A520 is a "little" CPU core model from Arm unveiled in TCS23 (total compute solution)
it serves as a successor to the CPU core ARM Cortex-A510. The Cortex-A500 CPU cores series generally focus on high efficiency, the CPU core can be paired with the other CPU cores in its family like ARM Cortex-A720 or/and Cortex-X4 in a CPU cluster.
Improvements
8% peak performance improvement over the Cortex-A510
Support only 64-bit applications
Up to 512 KiB of private L2 cache (From 256 KiB)
Add QARMA3 Pointer Authentication (PAC) algorithm support
Update to ARMv9.2
Architecture comparison
See also
ARM Cortex-X4, related high performance microarchitecture
ARM Cortex-A720, related efficient sustained performance microarchitecture
Comparison of ARMv8-A cores, ARMv8 family
References
ARM processors | ARM Cortex-A520 | [
"Technology",
"Engineering"
] | 196 | [
"Computing stubs",
"Computer engineering stubs",
"Computer engineering"
] |
73,963,826 | https://en.wikipedia.org/wiki/Marta%20Schuhmacher | Marta Schuhmacher is a distinguished professor of environmental technology at the Department of Chemical Engineering at Universitat Rovira i Virgili, Tarragona, Spain. She is known for her work linking the presence of chemicals with environmental and human health issues.
Career
Schuhmacher did her degree in Chemistry (1976), and received a B.Sc. in 1991 from UNED, and completed her Ph.D. in 1990 from University of Zaragoza, Spain. Later, she also did a master's in engineering and environmental management from School of Industrial Organization, Ministry of Industry and Energy, Madrid, Spain (1995).
She has been teaching at DEQ since 1993, and in 2009, she became a professor or Catedrática. Since 2015, she has been a distinguished professor at the University of Rovira i Virgili. She served as the director of the AGA Research Group (Environmental Analysis and Management) of the Chemical Engineering department of the Rovira i Virgili University and the Tecnatox center till 2023. As of 2024 she is a full professor of environmental technology at the Universitat Rovira i Virgili.
Research
Schuhmacher is known for her work in examining pollution, specifically suspended particulate matter, in schools. She has also examined the presence of microplastics in marine systems, and compared models used to define toxicity. Schuhmacher has focused on the development of techniques for risk assessment, and their application to new and emerging chemical compounds, and very particularly to that of mixtures.
Selected publications
Awards and honors
Schuhmacher received recognition with the President Macià Work Medal in 2023.
References
Living people
University of Zaragoza alumni
Academic staff of the University of Rovira i Virgili
Toxicologists
Women toxicologists
Spanish toxicologists
Year of birth missing (living people) | Marta Schuhmacher | [
"Environmental_science"
] | 375 | [
"Toxicologists",
"Toxicology"
] |
73,964,350 | https://en.wikipedia.org/wiki/Plancherel%E2%80%93Rotach%20asymptotics | The Plancherel–Rotach asymptotics are asymptotic results for orthogonal polynomials. They are named after the Swiss mathematicians Michel Plancherel and his PhD student Walter Rotach, who first derived the asymptotics for the Hermite polynomial and Laguerre polynomial. Nowadays asymptotic expansions of this kind for orthogonal polynomials are referred to as Plancherel–Rotach asymptotics or of Plancherel–Rotach type.
The case for the associated Laguerre polynomial was derived by the Swiss mathematician Egon Möcklin, another PhD student of Plancherel and George Pólya at ETH Zurich.
Hermite polynomials
Let denote the n-th Hermite polynomial. Let and be positive and fixed, then
for and
for and
for and complex and bounded
where denotes the Airy function.
(Associated) Laguerre polynomials
Let denote the n-th associate Laguerre polynomial. Let be arbitrary and real, and be positive and fixed, then
for and
for and
for and complex and bounded
.
Literature
References
Analysis
Asymptotic analysis
Orthogonal polynomials | Plancherel–Rotach asymptotics | [
"Mathematics"
] | 226 | [
"Mathematical analysis",
"Asymptotic analysis"
] |
73,964,415 | https://en.wikipedia.org/wiki/NATO%20Star | The NATO Star is a sculpture situated in the court of honor of the North Atlantic Treaty Organization's (NATO) headquarters in Brussels, Belgium.
The sculpture was unveiled in 1971. It symbolises the bond between Europe and North America, and is inspired by the alliance's flag, which was introduced in 1953.
At NATO's old headquarters, the star was surrounded by the flags of the NATO member countries. When NATO moved to its new headquarters, the star moved across Boulevard Leopold III to its new home on Saturday 28 May 2016.
See also
NATO headquarters
Flag of NATO
References
External links
The NATO Star Sculpture, NATO official website
NATO's Mystery Sculpture, Espionart
Buildings and structures in Brussels
Symbols of NATO
Sculptures in Belgium
Steel sculptures
Star symbols | NATO Star | [
"Mathematics"
] | 153 | [
"Symbols",
"Star symbols"
] |
73,966,198 | https://en.wikipedia.org/wiki/Sclerococcum%20gelidarium | Sclerococcum gelidarium is a species of lichenicolous fungus belonging to the family Dactylosporaceae. It has only been reported from Iceland where it grown on Placopsis gelida, from where the species got its name.
References
Eurotiomycetes
Fungi of Iceland
Fungi described in 2000
Fungus species
Taxa named by Javier Angel Etayo Salazar
Lichenicolous fungi | Sclerococcum gelidarium | [
"Biology"
] | 83 | [
"Fungi",
"Fungus species"
] |
73,966,337 | https://en.wikipedia.org/wiki/HD%20179433 | HD 179433, also known as HR 7281 or rarely 49 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a yellow-hued point of light with an apparent magnitude of 5.91. Gaia DR3 parallax measurements imply a distance of 329 light-years, and it is currently drifting closer with a heliocentric radial velocity of . At its current distance, HD 179433's brightness is diminished by interstellar extinction of 0.22 magnitudes and it has an absolute magnitude of +1.11.
HD 179433 has a stellar classification of G8 III, indicating that it is an evolved red giant. It has 2.45 times the mass of the Sun but at the age of 727 million years, it has expanded to 8.26 times the Sun's radius. It radiates 43.3 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of . HD 197433 has a near solar metallicity at [Fe/H]= −0.0004 and it spins modestly with a projected rotational velocity of .
References
G-type giants
Corona Australis
Coronae Australis, 49
CD-45 13054
179433
094556
7281 | HD 179433 | [
"Astronomy"
] | 276 | [
"Corona Australis",
"Constellations"
] |
73,966,770 | https://en.wikipedia.org/wiki/Bobkov%27s%20inequality | In probability theory, Bobkov's inequality is a functional isoperimetric inequality for the canonical Gaussian measure. It generalizes the Gaussian isoperimetric inequality.
The equation was proven in 1997 by the Russian mathematician Sergey Bobkov.
Bobkov's inequality
Notation:
Let
be the canonical Gaussian measure on with respect to the Lebesgue measure,
be the one dimensional canonical Gaussian density
the cumulative distribution function
be a function that vanishes at the end points
Statement
For every locally Lipschitz continuous (or smooth) function the following inequality holds
Generalizations
There exists a generalization by Dominique Bakry and Michel Ledoux.
References
Probabilistic inequalities | Bobkov's inequality | [
"Mathematics"
] | 145 | [
"Theorems in probability theory",
"Probabilistic inequalities",
"Inequalities (mathematics)"
] |
73,966,884 | https://en.wikipedia.org/wiki/Scutula%20stereocaulorum | Scutula stereocaulorum is a species of lichenicolous fungus in the family Ramalinaceae.
Host species
Scutula stereocaulorum can use lichens of the genus Stereocaulon as hosts. It is very common and so far the following host species have been recorded:
Stereocaulon alpinum
Stereocaulon depressum
Stereocaulon glareosum
Stereocaulon groenlandicum
Stereocaulon rivulorum
Stereocaulon saxatile
Stereocaulon tornoense
Stereocaulon vesuvianum
References
Lecanorales
Fungi described in 1865
Fungi of Europe
Taxa named by Martino Anzi
Fungus species | Scutula stereocaulorum | [
"Biology"
] | 145 | [
"Fungi",
"Fungus species"
] |
73,967,005 | https://en.wikipedia.org/wiki/Matsaev%27s%20theorem | Matsaev's theorem is a theorem from complex analysis, which characterizes the order and type of an entire function.
The theorem was proven in 1960 by Vladimir Igorevich Matsaev.
Matsaev's theorem
Let with be an entire function which is bounded from below as follows
where
and
Then is of order and has finite type.
References
Theorems in complex analysis | Matsaev's theorem | [
"Mathematics"
] | 77 | [
"Theorems in mathematical analysis",
"Theorems in complex analysis"
] |
73,968,272 | https://en.wikipedia.org/wiki/Batis%20argillicola | Batis argillicola is a species of flowering plant in the family Bataceae, native to southern New Guinea and northern Australia. It is a monoecious succulent shrub from tall, typically found in tidal flats and clay pans.
References
Brassicales
Halophytes
Succulent plants
Flora of New Guinea
Flora of Western Australia
Flora of the Northern Territory
Flora of Queensland
Plants described in 1956 | Batis argillicola | [
"Chemistry"
] | 83 | [
"Halophytes",
"Salts"
] |
73,970,876 | https://en.wikipedia.org/wiki/Cetoniacytone%20A | Cetoniacytone A is a secondary metabolite classified in the family of C7N aminocyclitols which include other natural products such as validamycin A, acarbose, and epoxyquinomicin. Cetoniacytone A was first identified from a culture of Actinomyces sp. (strain Lu 9419), an endosymbiotic Gram-positive bacillus found in the intestines of a rose chafer (Cetonia aureata). Preliminary feeding studies with [U-13C3]glycerol identified the core moiety, cetoniacytone, to be derived via the pentose phosphate pathway. Although agar plate diffusion assay studies of cetoniacytone A showed no antimicrobial activity against Gram-positive and Gram-negative bacteria, cetoniacytone A has demonstrated a significant growth inhibitory effect against human cancer cell lines including hepatocellular carcinoma (HEP G2) and breast adenocarcinoma (MCF 7).
Biosynthesis
Feeding experiments conducted by Zeeck and co-workers established the synthesis of cetoniacytone A to proceed via the pentose phosphate pathway with sedoheptulose 7-phosphate as the key intermediate. Sedoheptulose 7-phosphate first undergoes a cyclization catalyzed by 2-epi-5-epi-valiolone synthase (CetA) yielding 2-epi-5-epi-valiolone. Following the cyclization, 2-epi-5-epi-valiolone epimerase (CetB) results in an inversion of the stereochemistry of the alcohol alpha to the ketone forming 5-epi-valiolone. Next, CetL, a type of oxidoreductase, results in the oxidation of the C-4 hydroxyl group to give 2-keto-5-epi-valiolone followed by a transamination catalyzed by aminotransferases CetM to give 2-amino-5-epi-valiolone. The sequential reactions depicted in the dashed box represent putative pathways that involve oxidoreductase, dehydrogenase, and hypothetical proteins related to the cupin superfamily to yield cetoniacytone B. Lastly, cetoniacytone B is acetylated via an arylamine N-acetyltransferase (CetD) to yield cetoniacytone A.
References
Secondary metabolites
Cyclic ketones
Acetamides
Epoxides
Diols
Heterocyclic compounds with 2 rings | Cetoniacytone A | [
"Chemistry"
] | 560 | [
"Chemical ecology",
"Metabolism",
"Secondary metabolites"
] |
73,971,166 | https://en.wikipedia.org/wiki/Third%20medium%20contact%20method | The third medium contact (TMC) is an implicit formulation used in contact mechanics. Contacting bodies are embedded in a highly compliant medium (the third medium), which becomes increasingly stiff under compression. The stiffening of the third medium allows tractions to be transferred between the contacting bodies when the third medium between the bodies is compressed. In itself, the method is inexact; however, in contrast to most other contact methods, the third medium approach is continuous and differentiable, which makes it applicable to applications such as topology optimization.
History
The method was first proposed in 2013 by , Jörg Schröder, and Alexander Schwarz, where a St. Venant-Kirchhoff material was used to model the third medium. This approach required explicit treatment of surface normals and continued to be used until 2017, when Bog et al. simplified the method by applying a Hencky material with the inherent property of becoming rigid under ultimate compression. This property made the explicit treatment of surface normals redundant, transforming the third medium contact method into a fully implicit method, contrasting with the more widely used Mortar methods or Penalty methods. However, at this stage, the third medium contact method could only handle very small degrees of sliding, and a friction model for TMC had yet to be developed. The rising popularity of Mortar methods, which emerged in the same period with a rigorous mathematical foundation and rapid development and adoption, overshadowed the TMC method. Consequently, TMC was abandoned at an early stage and remained largely unknown in contact mechanics.
In 2021, the method was revived when Gore Lukas Bluhm, Ole Sigmund, and Konstantinos Poulios rediscovered it, realizing that a highly compliant void material could transfer forces in a topology optimization setting. Bluhm et al. added a new regularization to stabilize the third medium, enabling the method to contact problems involving moderate sliding and thus making it practically applicable. The use of TMC in topology optimization was refined in subsequent work and applied to more complex problems.
In 2024, Frederiksen et al. proposed a crystal plasticity-inspired scheme to include friction. This involved adding a term to the material model to contribute to high shear stresses in the contact interface, along with a plastic slip scheme to release shear stresses and accommodate sliding. During the same period, new regularization methods were proposed, and the method was extended to thermal contact by Dalklint et al. and utilized for pneumatic actuation by Faltus et al.
Principles
Material model
TMC relies on a material model for the third medium, which stiffens under compression. The most commonly applied material models are of a neo-Hookean type, characterized by a strain energy density function:
,
where is the bulk modulus, is the shear modulus, and is the deformation gradient tensor of the displacement field .
As the current material volume approaches zero, this material model exhibits the characteristic of becoming infinitely stiff. Consequently, when the third medium is compressed, its volume remains positive and finite. This ensures that if two solids are embedded in a third medium with significantly lower bulk and shear moduli, the third medium can still transfer substantial forces to deform the solids when sufficiently compressed, as its stiffness becomes comparable to that of the embedded solids.
Regularization
While the neo-Hookean material model can be stable for contact without sliding, sliding often leads to instability. To address this, regularization techniques are applied to the strain energy density function.
Regularization is typically achieved by adding a regularization term to the strain energy density function of the material model. A common approach is the HuHu regularization, expressed as:
,
where represents the augmented strain energy density of the third medium, is the regularization term representing the inner product of the spatial Hessian of by itself, and is the underlying strain energy density of the third medium, e.g. a neo-Hookean solid or another hyperelastic material.
The HuHu regularization was the first regularization method specifically developed for TMC. A subsequent refinement is known as the HuHu-LuLu regularization, expressed as:
,
where is the Laplacian of the displacement field , and is the trace of the identity matrix corresponding to the problem's dimension (2D or 3D). The LuLu term is designed to mitigate the penalization of bending and quadratic compression deformations while maintaining the penalization of excessive skew deformations, thus preserving the stabilizing properties of the HuHu regularization. This reduced penalization on bending deformations enhances the accuracy of modeling curved contacts, particularly beneficial when using coarse finite element meshes. Similarly, the reduced penalization on quadratic compression is advantageous in topology optimization applications, where finite elements with varying material densities undergo non-uniform compression.
An alternative and more complex regularization approach involves penalizing volume change and rotations, initially proposed by Faltus et al. This approach requires further extension to 3D applications. A later improvement by Wriggers et al. directly utilizes the rotation tensor instead of the approximation used in .
Friction
The integration of friction into the TMC method represents a significant advancement in simulating realistic contact conditions, addressing the previous limitations in replicating real-world scenarios. Currently, there is only one approach available for adding friction. This approach introduces shear stress to the contact and releases it through plastic slip if the contact is sliding.
When a neo-Hookean material model is used to represent the third medium, it exhibits much greater stiffness in compression compared to shear during contact. To address this and provide shear resistance, an anisotropic term is incorporated into the neo-Hookean material model. This modification rapidly builds up shear stress in compressed regions of the third medium, which is crucial for accurately modeling frictional contact.
In this formulation, the extended strain energy density expression with the added shear term is:
,
where:
is a scaling parameter,
is a unit vector parallel to the direction of sliding,
is a unit vector perpendicular to the contact interface, and
is the right Cauchy-Green tensor of the elastic deformation.
The shear extension works by penalising the contribution in associated with shear in the slip direction .
To release the shear stresses at the onset of sliding, a framework inspired by crystal plasticity is employed. This includes a yield criterion specifically designed to replicate the effects of Coulomb friction. This framework allows the model to simulate the onset of sliding when the shear stress, provided by the added anisotropic term, exceeds a certain threshold, effectively mimicking real-world frictional behavior. The yield criterion, based on the Coulomb friction model, determines when sliding occurs, initiating once the shear stress surpasses a critical value.
Applications
TMC is widely used in computational mechanics and topology optimization due to its ability to model contact mechanics in a differentiable and fully implicit manner. One of the key advantages of TMC is that it eliminates the need to explicitly define surfaces and contact pairs, thereby simplifying the modeling process.
In topology optimization, TMC ensures that sensitivities are properly handled, enabling gradient-based optimization approaches to converge effectively and produce designs with internal contact. Notable designs achieved through this approach include compliant mechanisms such as hooks, bending mechanisms, and self-contacting springs. The design of metamaterials is a common application for topology optimization, where TMC has expanded the range of possible designs. Additionally, soft springs and pneumatically activated systems, which are useful in the design of soft robots, have been modeled using TMC.
TMC has also been extended to applications involving frictional contact and thermo-mechanical coupling. These advancements enhance the method’s utility in modeling real-world mechanical interfaces.
See also
Contact mechanics
Hyperelastic materials
Topology optimization
References
Engineering
Mechanical engineering
Contact mechanics
Friction
Solid mechanics | Third medium contact method | [
"Physics",
"Chemistry",
"Engineering"
] | 1,583 | [
"Mechanical phenomena",
"Solid mechanics",
"Physical phenomena",
"Friction",
"Physical quantities",
"Force",
"Applied and interdisciplinary physics",
"Surface science",
"Mechanics",
"Mechanical engineering"
] |
73,971,739 | https://en.wikipedia.org/wiki/Praiseworld%20Radio | Praiseworld Radio is Nigeria first Gospel online radio best known for broadcasting 24/7 Urban, and Gospel hip hop music. The radio began broadcasting on June 1, 2012. In 2014, Praiseworld won the Nigerian Broadcasters Merit Awards for Best Online Radio Station. In 2019, Praiseworld won the Africa Gospel Music Awards for Online Gospel Station of Excellence.
History
Praiseworld Radio was founded in 2012 by Tola Omoniyi, a Nigerian podcaster, hosting the Telling Bible Stories podcast.
Overview
On 9 February 2013, Nikki Laoye announce her radio show titled "Girls Rock with Nikki Laoye" to air for 2 hours, weekly. From 23 March to 27 March 2020, PraiseWorld Radio held its radio conference titled: Faith Hope Love Conference 2020.
Notable shows
Present
The Praise O’Clock Show (With. TOLA)
Past
Girls Rock with Nikki Laoye
Awards and nominations
References
Products introduced in 2012
Internet radio
Nigerian music websites
Music review websites
Nigerian news websites | Praiseworld Radio | [
"Technology"
] | 192 | [
"Multimedia",
"Internet radio"
] |
73,971,837 | https://en.wikipedia.org/wiki/Erwin-F%C3%A9lix%20Lewy-Bertaut | Erwin-Félix Lewy-Bertaut (9 February 1913 – 6 November 2003), also known separately as Erwin Lewy, Félix Bertaut, and E. F. Bertaut, or Erwin Félix Lewy-Bertaut, was a German-born French materials scientist who led a former life as a law school student in Nazi Germany. He was renowned internationally for his work in magnetic crystallography, X-ray diffraction, and neutron scattering. He was a research director at CNRS, a member of the French Academy of Sciences and played an important role in the creation of Institut Laue–Langevin, a leading neutron research facility in the world.
Biography
Lewy-Bertaut was born with the name Erwin Lewy to Jewish parents in Leobschütz of Silesia (then in Germany). The year 1930 marked a significant shift as his mother passed away, prompting their entire family's relocation to Gleiwitz amidst an era of economic turmoil and the ascent of Nazism. Following this, in 1931, Lewy embarked on his legal studies first at the University of Freiburg and subsequently in University of Breslau (now Wrocław). As Hitler's ascendancy to power unfurled in Germany, instituting a "numerus clausus" that effectively precluded Jewish individuals from university access, Lewy-Bertaut left for Bordeaux, France. There, the Rothschild Foundation awarded him a scholarship, facilitating his enrollment at the University of Bordeaux, where Lewy-Bertaut studied chemical engineering, physics, and mathematics. After graduation, Lewy-Bertaut undertook roles as a mathematics and German tutor and acquired French citizenship in 1936. In 1938, Lewy-Bertaut worked as an engineer at Institut du pin and joined the French army as a military volunteer near Bordeaux. At the onset of the conflict in 1940, Colonel Faure entrusted him with the military records of a missing soldier, Félix Bertaut, and he adopted this name permanently.
Lewy-Bertaut worked as a chemical engineer between 1941 and 1943 to enhance the durability of bicycle brakes crafted from agglomerated cork. To elude police inspections and evade mandatory labor service, he went to Paris, where he collaborated with Marcel Mathieu at the Laboratoire Central des Poudres. Subsequently, he partnered with Emmanuel Grison, who tutored him in the utilization of the International Tables for Crystallography. Regrettably, a bicycle registration check by the police led to his summons to the Paris Prefecture. Lewy-Bertaut moved to Grenoble in the Italian-occupied zone to meet Louis Néel, who was temporarily withdrawn from the University of Strasbourg and has founded the Laboratoire d'Electrostatique et de Physique du Métal (LEPM, now Institut Néel) in 1946, which was the first CNRS laboratory outside the Paris region. Lewy-Bertaut also took over Erwin Lewy's qualifications in 1946 and obtained a research grant from the CNRS under his wartime identity, "Félix Bertaut". Lewy-Bertaut eventually finished his thesis under Louis Néel in 1953 and André Guinier was also an examiner. His thesis involves X-ray diffraction studies of powder granulometry, which later became known as the Bertaut-Warren-Averbach method. Immediately after his thesis, Lewy-Bertaut started establishing his group at the LEPM that formed the basis of the X-ray department to carry out research in cristallography, along with Francis Forrat and Professor René Pauthenet, distinguished themselves with their work on garnet ferrites, from which the theory of antiferromagnetism and ferrimagnetism was built up.
In 1949, Lewy-Bertaut read a one-page publication by Clifford G. Shull and J. Samuel Smart, which recovered the magnetic structure of MnO from neutron diffraction and validated Louis Néel's work on antiferromagnetism. In 1953, Lewy-Bertaut secured a Fulbright grant to visit Raymond Pepinski's laboratory at State College, Pennsylvania and accessed the neutron diffraction facilities at the Brookhaven National Laboratory, where he acquainted himself with neutron experiments under the guidance of Lester Corliss and Julius Hastings. Upon returning to Grenoble, Lewy-Bertaut was placed in charge of the development of the military facility Polygone d'Artillerie (now Polygone Scientifique) into a neutron research center, which later became the Institut Laue-Langevin, an international research facility collaboratively funded by the French and German governmental agencies. Lewy-Bertaut was CNRS research director in 1956 and the scientific director of CNRS in 1961.
Research
Lewy-Bertaut made an enormous contributions to magnetic and neutron crystallography, including the use of group theory in describing magnetic structures. When the International Union of Crystallography (IUCr) decided to finalize the volume on the symmetry of space groups in the International Tables of Crystallography, he was a member of the ad hoc committee and contributed in particular to the definition of magnetic groups. He used the symmetry of crystals to propose all possible magnetic structures. This "Bertaut method" was very useful for complex structures. Lewy-Bertaut also developed what is known as structure factor algebra and solved the structure of complex compounds such as the non-stoichiometric pyrrhotite.
Honors and distinctions
Lewy-Bertaut was a member of the IUCr executive committee between 1975 and 1981. He was co-founder of its "Neutron Diffraction" commission and co-founder and chairman of its "International Tables" and "Charge, Spin and Momentum Density" commissions. He was the IUCr representative on the Solid State Commission of the International Union of Pure and Applied Physics (IUPAP) between 1966 and 1972 and was secretary and then chairman of the Solid State Physics Section. He was editor or co-editor of numerous scientific journals. From 1958 to 1982, he was scientific advisor to various institutes, including the Commissariat à l'Energie Atomique (CEA), CNRS, ILL, and the Max Planck Institute for Metal Research in Stuttgart.
Lewy-Bertaut received the CNRS Silver Medal in 1959. He received the Knight of the Legion of Honour and Commander of the National Order of Merit. In 1979, Lewy-Bertaut was elected a full member of the Académie des Sciences. In 1986, Lewy-Bertaut received the Gregori Aminoff Prize from the Royal Swedish Academy of Sciences.
Further reading
Erwin Félix Lewy-Bertaut, Notice nécrologique de l’Académie des Sciences, J. Villain (2004).
La vie et l'oeuvre scientifique d’Erwin Félix Lewy-Bertaut, Séance publique Académie des Sciences du 8 novembre 2005, J-Cl. Pecker (2005)
Journée Scientifique « E.F. BERTAUT » May 2006, CNRS-Polygone, Grenoble.
References
1913 births
2003 deaths
Crystallographers
20th-century French physicists
Members of the French Academy of Sciences
University of Bordeaux alumni
University of Breslau alumni
Grenoble Alpes University alumni
Research directors of the French National Centre for Scientific Research
French National Centre for Scientific Research scientists
Recipients of the Legion of Honour
People from Głubczyce
Fellows of the American Physical Society | Erwin-Félix Lewy-Bertaut | [
"Chemistry",
"Materials_science"
] | 1,561 | [
"Crystallographers",
"Crystallography"
] |
73,971,918 | https://en.wikipedia.org/wiki/Malaysian%20Green%20Transition | The Malaysia Green Transition refers to the sustainable development strategy implemented by the Malaysian government to combat climate change, stimulate economic growth, and improve societal well-being. The shift towards a greener economy began in earnest in the early 2020s, with ambitious targets set to drastically reduce greenhouse gas emissions and incorporate renewable energy sources into the national grid.
Overview
Following global trends and increasing environmental concerns, Malaysia recognized the pressing need for a transition to a green, sustainable economy. The Malaysian government announced a comprehensive plan that centered on sustainable development, green technology, biodiversity preservation, and climate change mitigation. This shift, known as the Malaysia Green Transition, aims to decarbonize various sectors, promote renewable energy sources, and establish a circular economy.
In 2024, the Malaysian government launched the Energy Exchange Malaysia (Enegem), a platform designed to facilitate the cross-border trade of green electricity within the ASEAN region, aligning with global sustainability efforts and the Asean Power Grid Initiative aimed at integrating regional power systems. Enegem initiated with a 100-megawatt pilot auction to supply green electricity from Peninsular Malaysia to Singapore, targeting licensed Renewable Energy (RE) Bidders in the Singapore Electricity Market. This initiative enhances regional energy cooperation and promotes the development of renewable energy sources across Southeast Asia.
Policy framework and initiatives
Green Technology Master Plan (2021–2030)
The Green Technology Master Plan was one of the first significant policy frameworks laid out by the government to guide the green transition. This blueprint highlights six sectors: energy, manufacturing, building, transport, waste, and water. The plan set specific goals, including achieving 40% renewable energy in the electricity mix by 2035 and enhancing energy efficiency in the manufacturing and building sectors.
National Biodiversity Policy (2022–2030)
The National Biodiversity Policy seeks to protect and manage Malaysia's rich biodiversity while harnessing its potential for sustainable economic development. The policy aims to integrate biodiversity considerations into all relevant sectors and decision-making processes.
Sustainable and Circular Economy Roadmap (2023-2040)
The government introduced the Sustainable and Circular Economy Roadmap to transition the country towards a circular economy. The approach promotes the efficient use of resources, waste minimization, and the regeneration of natural systems.
Progress and achievements
Since the onset of the Malaysia Green Transition, notable progress has been made in several sectors.
The country made significant strides in expanding its renewable energy portfolio, particularly in solar and hydroelectric power. By 2023, the share of renewable energy in the national grid rose to 22%, a significant increase from the previous decade.
Energy efficiency measures have been implemented across various sectors, with considerable progress in the building and industrial sectors. Mandatory energy audits, green building index certifications, and efficient energy management systems have reduced the energy intensity of these sectors.
Malaysia has implemented several waste-to-energy projects, transforming municipal waste into energy. An increase in recycling rates and the introduction of policies targeting single-use plastics have contributed to a shift towards a circular economy.
Challenges and future directions
While the Malaysia Green Transition has seen significant achievements, it faces several challenges, including economic restructuring, financing green technologies, and public awareness and participation.
The Malaysian government plans to continue strengthening its green policies and initiatives, focusing on a just transition that ensures equitable opportunities and benefits for all citizens. Future directions include greater emphasis on nature-based solutions, blue economy, and digitalization in the green economy.
See also
Environmental issues in Malaysia
Renewable energy in Malaysia
Economy of Malaysia
Circular economy
References
Economy of Malaysia
Renewable energy in Malaysia
Climate change in Malaysia
Energy policy of Malaysia
Climate change policy
Nature conservation in Malaysia
Sustainable development
2020s in Malaysia
Emissions reduction
Renewable energy commercialization
Environmental policies approved in 2021
Environmentalism in Malaysia | Malaysian Green Transition | [
"Chemistry"
] | 752 | [
"Greenhouse gases",
"Emissions reduction"
] |
73,972,756 | https://en.wikipedia.org/wiki/Universal%20International%20Shared%20Cost%20Number | Universal International Shared Cost Number (UISCN) is part of the E.164 telephone numbering space that includes international telephone numbers where the call costs are split between the caller and the called. An international shared-cost number allows the calling party to make the call at national rates, since the costs of any international routing will be borne by the called party.
The International Telecommunication Union (ITU) has allocated the country code 808 to this service.
As of 2023, the only companies that had requested UISCN number allocation were Swisscom (Switzerland), SMSRelay (Switzerland, now defunct) and Mr Next Id (now DTMS; Germany).
See also
Shared-cost service
List of country calling codes
References
International telecommunications
Telephone numbers
Further reading | Universal International Shared Cost Number | [
"Mathematics"
] | 154 | [
"Mathematical objects",
"Numbers",
"Telephone numbers"
] |
73,973,042 | https://en.wikipedia.org/wiki/Bedford%20Green%20Wheel | The Bedford Green Wheel is a network of traffic free paths and quiet routes for cyclists and walkers in and around Bedford, England. This network included 'spokes' linking into the town centre. The network links parks, nature reserves, countryside and homes. This project was announced as part of Bedford Borough Council's Green Infrastructure Plan 2009.
The Cycling Campaign for North Bedfordshire promotes and encourages the use of the Bedford Green Wheel.
References
Cycleways in England
Sustainable transport
Transport in Bedford | Bedford Green Wheel | [
"Physics"
] | 96 | [
"Physical systems",
"Transport",
"Sustainable transport"
] |
73,973,823 | https://en.wikipedia.org/wiki/HD%20170384 | HD 170384, also known as HR 6931 or rarely 11 G. Coronae Australis, is a solitary white-hued star located in the southern constellation Corona Australis. It has an apparent magnitude of 6.02, making it barely visible to the naked eye, even under ideal conditions. The object is located relatively close at a distance of 229.1 light-years based on Gaia DR3 parallax measurements and it is drifting closer with a heliocentric radial velocity of . At its current distance, HD 170384's brightness is diminished by interstellar extinction of 0.28 magnitudes and it has an absolute magnitude of +1.86.
This object has a stellar classification of A3 V, indicating that it is an ordinary A-type main-sequence star. It has double the Sun's mass and 1.91 times the radius of the Sun. It radiates 16.7 times the luminosity of the Sun from its photosphere at an effective temperature of . HD 170384 has a near solar metallicity at [Fe/H] = −0.01 (97% solar) and it is estimated to be 544 million years old, having completed 45% of its main sequence lifetime. Like many hot stars HD 170384 spins rapidly, having a projected rotational velocity of and an estimated rotation period of 19.2 hours.
References
A-type main-sequence stars
Corona Australis
Coronae Australis, 11
CD-41 12871
170384
090759
6931 | HD 170384 | [
"Astronomy"
] | 322 | [
"Corona Australis",
"Constellations"
] |
73,974,267 | https://en.wikipedia.org/wiki/%CE%92-Cyclocitral | β-Cyclocitral (beta-cyclocitral) is an apocarotenoid derived from the C7 oxidation of β-carotene. This apocarotenoid has revived interest due to its roles in plant development. β-cyclocitral has been found endogenously in a variety of organisms including plants, cyanobacteria, fungi and animals. β-Cyclocitral is a volatile compound that contributes to the aroma of various fruits, vegetables and ornamental plants. In plants, β-cyclocitral was found to be an important regulator in root development.
Application
β-Cyclocitral is used as an analytical standard for the determination of volatile organic compounds in saffron due to its analog structure to safranal.
Because β-cyclocitral is associated with cyanobacteria death, it is an analyte that can be tracked in bodies of water to monitor cyanobacteria blooms.
It has also been found to promote the growth of roots in rice, prompting its consideration as a potential agricultural tool.
Biosynthesis
The biosynthesis of β-cyclocitral relies on the formation of β-carotene through the isoprenoid biosynthetic pathway underpinning carotenoid formation. Similar to other apocarotenoids, the formation of β-cyclocitral can occur via the enzymatic and non-enzymatic oxidative cleavage of double bonds in β-carotene. For β-cyclocitral to form, the cleavage of C7-C8 double bonds are needed. While no enzyme has been identified to have high specificity for the production of β-cyclocitral, a carotenoid cleavage dioxygenase (CCD4) has been identified as being capable of cleaving β-carotene at the needed position. 13-lipoxygenase (LOX2) has also been identified to cleave β-carotene at the C7 position. β-cyclocitral can also be formed from the direct oxidation of β-carotene by reactive oxygen species, especially singlet oxygen (1O2). In plants, 1O2 is mainly produced from excited chlorophylls in the reaction center of PSII where β-carotene serves to quench the reactive oxygen species.
References
Aldehydes
Cyclohexenes
Monoterpenes
Plant metabolism | Β-Cyclocitral | [
"Chemistry"
] | 525 | [
"Plant metabolism",
"Metabolism"
] |
73,974,319 | https://en.wikipedia.org/wiki/Phaffia | Phaffia is a genus of fungi in the order Cystofilobasidiales. The genus comprises orange-red yeasts that form basidia directly from yeast cells, lack hyphae throughout their life cycle, and produce astaxanthin, a carotenoid used as an additive in animal feed to enhance colour in shrimp, salmon, and poultry eggs and also as an antioxidant in dietary supplements.
The genus was named after the Dutch specialist Herman Phaff who first isolated the type species from slime fluxes of Japanese and North American trees in the 1960s.
The genus Xanthophyllomyces was proposed for the teleomorphic (basidia-bearing) state of Phaffia. Following changes to the International Code of Nomenclature for algae, fungi, and plants, however, the practice of giving different names to teleomorph and anamorph forms of the same fungus was discontinued, meaning that Xanthophyllomyces became a synonym of the earlier name Phaffia.
References
Tremellomycetes
Taxa described in 1976
Basidiomycota genera
Yeasts | Phaffia | [
"Biology"
] | 232 | [
"Yeasts",
"Fungi"
] |
73,975,599 | https://en.wikipedia.org/wiki/Lyngbyastatins | Lyngbyastatins 1 and 3 are cytotoxic cyclic depsipeptides that possess antiproliferative activity against human cancer cell lines. These compounds, first isolated from the extract of a Lyngbya majuscula/Schizothrix calcicola assemblage and from L. majuscula Harvey ex Gomont (Oscillatoriaceae) strains, respectively, target the actin cytoskeleton of eukaryotic cells.
Biosynthesis
Lyngbyastatins 1 and 3 are encoded for by a 52 kb biosynthetic gene cluster (BGC) containing one polyketide synthase (PKS)/non-ribosomal peptide synthetase (NRPS) hybrid (LbnA), four NRPSs (LbnB-D, LbnF), and one PKS (LbnE).
Biosynthesis commences with PKS activity — thiolation of propanoic (Lyngbyastatin 1) or butyric (Lyngbyastatin 3) acid and subsequent loading onto the ketosynthase (KS) of LbnA. An acyl unit from malonyl CoA is then coupled onto the initial substrate via an acyltransferase (AT) and then methylated at the alpha carbon through a C-methyltransferase (CMT) before an aminotransferase (AmT) conducts a transamination of the initial substrate carbonyl. The latter half of LbnA follows traditional NRPS activity containing condensation (C), adenylation (A), and thiolation (T) domains to couple 2-hydroxy-3-methylvaleric acid, which is believed to be formed from the 2-oxo analog through PKS ketoreductase (KR) activity.
LbnB, a traditional NRPS, adds glycine into the growing thioester by its amino group. LbnC is another traditional NRPS that adds L-leucine and glycine, respectively, except the L-leucine domain possesses an active N-methyltransferase (NMT) domain that methylates the nitrogen of L-leucine.
NRPS LbnD then adds L-valine, L-tyrosine, and L or D-valine, respectively to the growing molecule. PKS LbnE couples an acyl unit from malonyl-CoA onto the C-terminus of the valine residue before a C-methyltransferase methylates the carbon alpha to the thioester twice to produce a quaternary alpha carbon.
NRPS LbnF completes the biosynthesis by coupling L-alanine before the thioesterase (TE) domain conducts a head-to-tail cyclization to produce the final depsipeptide products.
References
Depsipeptides | Lyngbyastatins | [
"Chemistry",
"Biology"
] | 611 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry"
] |
69,500,010 | https://en.wikipedia.org/wiki/Puerto%20Mosquito | The Puerto Mosquito Bioluminescent Bay (), or Mosquito Bio Bay, is a bay in the island of Vieques famous for its bioluminescence produced by the dinoflagellate Pyrodinium bahamense, which glows blue when agitated. This species of phytoplankton is found in bays in the Virgin Islands, Puerto Rico and The Bahamas.
History
According to legend, Puerto Mosquito is named after the Mosquito, the name of one of pirate Roberto Cofresí's ships. The bio bay was proclaimed a National Natural Landmark in 1980.
Bioluminescence
Bioluminescence is produced by the dinoflagellate Pyrodinium bahamense, which glows blue when agitated. Although the phytoplankton responsible for the phenomenon of bioluminescence is found throughout the Antilles, Puerto Mosquito is one of the seven year-round bioluminescent bays in the Caribbean. The bioluminescence is the product of a number of factors: the water conditions and ecosystem created by the surrounding mangrove forest (mostly Rhizophora mangle), the complete lack of modern development in the lagoon, the temperature of the water and the depth of the bay.
Recreation
The bright blue hues produced by the microorganisms during nights of very little moonlight or new moon attracts tourists to the bio bay. It is one of the three bio bays in Puerto Rico; the other two are Laguna Grande in Fajardo and La Parguera in Lajas. The bay and its surrounding mangrove forest are protected by the Vieques Bioluminescent Bay Natural Reserve and no swimming is allowed. Guided tours allow visitors to kayak in the bay and observe the bioluminescence. The bio bay is located near the beach community of Esperanza, between the barrios of Puerto Ferro and Puerto Real in Vieques, Puerto Rico.
Gallery
See also
La Parguera Nature Reserve
List of National Natural Landmarks in Puerto Rico
References
External links
Bahía Mosquito "Bahía Bioluminiscente", Vieques, Puerto Rico (Spanish)
Mosquito Bioluminescent Bay|Vieques (English)
IUCN Category III
Vieques, Puerto Rico
National Natural Landmarks in Puerto Rico
Bays of Puerto Rico
Tourist attractions in Puerto Rico
Bioluminescence
1980 establishments in Puerto Rico
Protected areas established in 1980 | Puerto Mosquito | [
"Chemistry",
"Biology"
] | 477 | [
"Biochemistry",
"Luminescence",
"Bioluminescence"
] |
69,500,966 | https://en.wikipedia.org/wiki/Rainwater%20management | Rainwater management is a series of countermeasures to reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of a site, with consideration of rainwater harvesting, urban flood management and rainwater runoff pollution control.
The continuous growth of human populations and the consequent growing need for drinking water is a global problem. Rainwater is an important source of drinking water, and as a free source of water, considerable quantities can be collected from roof catchments and other surface areas for various uses. Due to water shortages, rainfall events and flooding, attention has been given to rainwater management. Rainwater management re-conceptualizes urban rainwater, transforming it from a community risk to a resource for urban development, a good rainwater management is important for the design of sanitation systems and the environment, nowadays different methods of rainwater management have been developed, including reduction of impervious surfaces, separation of rainwater and sanitary sewers, collection and reuse of rainwater, and Low-impact development (LID).
Components
Rainwater harvesting and use
Rainwater harvesting (RWH) is the process of collecting and storing rainwater rather than letting it run off. Rainwater harvesting systems are increasingly becoming an integral part of the sustainable rainwater management "toolkit" and are widely used in homes, home-scale projects, schools and hospitals for a variety of purposes including watering gardens, livestock, irrigation, home use with proper treatment and home heating. For households it is effective in reducing electricity and greenhouse gas emissions and providing domestic water; for urban agriculture, it is effective in reducing rainwater runoff and related issues; and for industry, it provides sustainability of facilities and low financial resource utilization.
Rainwater harvested from roof structures or other compact surfaces is discharged through drains into storage tank, processed by treatment systems and then deployed in use facilities to complete the beneficial use of rainwater. Rainwater so treated is mainly used for irrigation, washing, laundry, and in some countries it is also considered as drinking water after the necessary purification.
Urban flood management
Urban flood management has now become one of the highest priorities in urban development, Urban flooding has a major impact on both public transportation systems and supply chains and is an important topic in rainwater management
Gray-green infrastructure
The use of combined sewer systems to treat excess rainwater runoff is common in older urban areas. The Combined Sewer System (CSS) collects rainwater runoff, domestic sewage and industrial wastewater into a single pipe. Combined sewer overflows (CSOs) occur when untreated wastewater is discharged to surface water beyond its hydraulic capacity, when this occurs, untreated rainwater and wastewater are discharged directly into nearby streams, rivers and other water bodies. Combined sewer overflows (CSOs) contain untreated or partially treated human and industrial waste, toxic materials and debris, and rainwater. a problem that is currently a key challenge for rainwater management and can lead to public health incidents. Gray-green infrastructure is the key technology to solve this problem and is the core technology of the currently introduced "sponge city". The implementation of gray infrastructure, such as upgrading drainage networks, storage facilities or pumping stations with large diameter pipes, is critical to drain rainwater from urban catchments, while most green infrastructure handles the storage and infiltration of rainwater and drainage of gray infrastructure
Constructed wetlands
Constructed wetlands for sewer overflows treatment are currently an effective and less costly option to prevent untreated wastewater from overflowing from polluted natural water bodies, and constructed wetlands that act as retention ponds during the rainy season can collect and treat rainwater due to their natural purification function, and produce high quality water for reuse after treatment by constructed wetlands with aeration system and soils infiltration system.
Separate sewer systems
The conversion of Combined Sewer System (CSS) to separate sewer systems with retention ponds will not only increase rainwater drainage and reduce the potential for urban flooding, but their own retention ponds will also retain pollutants, thereby reducing or preventing unnecessary pollution of a single receiving waters.
Land use
The ratio of pervious to impervious surfaces is important in flood management. Building vegetated spaces, such as parks integrated with urban facilities, can increase the amount of pervious area. For new and redevelopment projects, reduce the amount of impervious surfaces, such as buildings, roads, parking lots, and other structures.
Low-impact development (LID)
Low-impact development (LID) refers to systems and practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat. Low-impact development (LID) practices provide more sustainable solutions than traditional piping and storm ponds in rainwater management. The sustainability of LID practices is achieved primarily through the use of porous pavement, bioretention, green roofs, rainwater harvesting, and other rainwater management strategies. Bioretention can effectively retain large amounts of runoff, porous pavement can effectively infiltrate rainwater runoff, and green roofs can retain rainwater under a variety of climatic conditions. These methods create and restore green space and reduce the impact of built-up areas at the site and regional scales, promoting the natural flow of water within an ecosystem or watershed. Applied over a wide range of scales, LID can maintain or restore the hydrologic and ecological functions of a watershed.
Rainwater management in agriculture
Applying rainwater management, surface runoff can be collected and stored in hand-dug farm ponds. To enhance irrigation in dry conditions, earthen ridges were constructed to collect and prevent rainwater from flowing down the hillsides and slopes. Even during periods of low rainfall, enough water can be collected for crop growth. Rainwater management can increase the productivity of smallholder farmers in arid environments. Productivity of rainfed agriculture is improved through supplemental irrigation, especially when combined with soil fertility management.
Tools
Rainwater management as a means of multi-stage control and improvement of rainwater systems needs to go through multiple steps of analysis and design, and in the new era of Low-impact development, rainwater management has become more than just a task for engineers, rainwater management projects have tended to become Integrated project delivery (IPD), designers need to consider rainwater management issues at a much earlier stage to avoid The development and use of software such as Rainwater+ is now helping designers to implement rainwater management at the design stage, its more intuitive GUI and simple workflow ensures that designers with little to no experience in hydrology can use Rainwater+, which will reduce later building construction conflicts to facilitate communication between all parties and improve construction quality.
Terminologies
Low impact development (LID)
The term Low-impact development is commonly used in North America and New Zealand, and was first used in the United States by Barlow et al.
Water sensitive urban design (WSUD)
Water sensitive urban design (WSUD) is a concept widely accepted and partially acted on throughout Australia's federal and state governments.
Integrated urban water management (IUWM)
IUWM derives from the broader term, Integrated Water Management, which involves the integrated management of all parts of the water cycle within a watershed.
Sustainable urban drainage systems (SUDS)
SUDS established in a similar but separate design manual that includes Scotland and Northern Ireland as well as England and Wales, SUDS consists of a range of techniques and technologies based on the concept of replicating the natural, pre-development drainage of the site as closely as possible, culminating in a management system.
Best management practices
Best management practices are structural, vegetative or managerial practices used to treat, prevent or reduce water pollution. Structural BMPs. Extended Detention Ponds.
See also
Integrated urban water management
Urban flooding
Constructed wetlands
Low-impact development
Water-sensitive urban design
Sponge city
References
Civil engineering
Rainwater harvesting
Water management | Rainwater management | [
"Engineering"
] | 1,592 | [
"Construction",
"Civil engineering"
] |
69,503,348 | https://en.wikipedia.org/wiki/Middle%20ear%20implant | A middle ear implant is a hearing device that is surgically implanted into the middle ear. They help people with conductive, sensorineural or mixed hearing loss to hear.
Middle ear implants work by improving the conduction of sound vibrations from the middle ear to the inner ear. There are two types of middle ear devices: active and passive. Active middle ear implants (AMEI) consist of an external audio processor and an internal implant, which actively vibrates the structures of the middle ear. Passive middle ear implants (PMEIs) are sometimes known as ossicular replacement prostheses, TORPs or PORPs. They replace damaged or missing parts of the middle ear, creating a bridge between the outer ear and the inner ear, so that sound vibrations can be conducted through the middle ear and on to the cochlea. Unlike AMEIs, PMEIs contain no electronics and are not powered by an external source.
PMEIs are the usual first-line surgical treatment for conductive hearing loss, due to their lack of external components and cost-effectiveness. However, each patient is assessed individually as to whether an AMEI or PMEI would bring more benefit. This is especially true if the patient has already had several surgeries with PMEIs.
Active middle ear implant
Parts
An active middle ear implant (AMEI) has two parts: an internal implant and an external audio processor. The microphone of the audio processor picks up sounds from the environment. The processor then converts these acoustic signals into digital signals and sends them to the implant through the skin. The implant sends the signals to the Floating Mass Transducer (FMT): a small vibratory part that is surgically fixed either on one of the three ossicles or against the round window of the cochlea. The FMT vibrates and sends sound vibrations to the cochlea. The cochlea converts these vibrations into nerve signals and sends them to the brain, where they are interpreted as sound.
Indications
AMEIs are intended for patients with mild-to-severe sensorineural hearing loss, as well as those with conductive or mixed hearing loss. They can be used by adults and children over the age of 5.
Sensorineural hearing loss
An AMEI can be beneficial for patients with mild-to-severe sensorineural hearing loss who have an intact ossicular chain and healthy middle ear, but who either cannot wear hearing aids or who do not get sufficient benefit from them. Reasons for not being able to wear hearing aids include earmold allergies, skin problems, narrow, collapsed or closed ear canals, or malformed ears. In cases of sensorineural hearing loss, the FMT is usually attached to the incus.
Conductive or mixed hearing loss
An AMEI is also indicated for patients with conductive or mixed hearing loss with bone conduction thresholds from 45 dB in the low frequencies to 65 dB in the high frequencies. In these cases, the FMT can be coupled to various parts of the middle ear, depending on the patient's pathology:
The oval window, causing stimulation of the cochlea in patients without an ossicular chain.
The round window, causing reverse stimulation of the cochlea in patients without an ossicular chain.
The mobile stapes in patients with absence or fixation of other ossicles, usually in cases of chronic otitis media or malformations.
Efficacy
AMEIs have been shown by several studies to be equal or superior to both hearing aids and bone conduction implants. Lee et al used the PBmax test to study speech intelligibility in patients before and after receiving an AMEI. All patients had used hearing aids pre-implantation. The researchers found that speech intelligibility improved with the AMEI, particularly in patients with a down-sloping hearing loss. These findings were supported by Iwasaki et al, who found that both speech intelligibility and quality of life improved after implantation with an AMEI, applied to the round window.
AMEIs can also offer improved hearing performance over bone conduction implants for patients with mixed hearing loss. Mojallal et al found that patients whose mixed hearing loss was treated with an AMEI experienced both better word recognition and speech understanding in noise than those who received a bone conduction implant, providing that their bone conduction pure-tone average (0.5 to 4 kHz) was poorer than 35 dB HL.
Passive middle ear implant
Parts
Passive middle ear implants (PMEI) are ossicular replacement prostheses designed to replace some or all of the ossicular chain in the middle ear. They create a bridge between the outer ear and the inner ear, so that sound vibrations can be conducted through the middle ear and on to the cochlea
There are two types of PMEIs: tympanoplasty implants and stapes implants. Tympanoplasty implants (also known as PORPs or TORPs) are suitable for patients with a mobile stapes footplate, ie. a stapes footplate that moves in the normal way. Either a partial or a total tympanoplasty implant can be used, depending on the condition of the stapes. If the stapes is fixed and cannot transfer vibrations to the inner ear, then a stapes implant would be used.
PMEIs are made from different materials including titanium, teflon, hydroxylapatite, platinum, and nitinol, all of which are suitable for use within the human body. Titanium implants can safely undergo MRIs of up to 7.0 Tesla.
Indications
Tympanoplasty implant
The tympanoplasty implant is indicated in cases of congenital or acquired defects of the ossicular chain, due to e.g.:
Chronic otitis media
Traumatic injury
Malformation
Cholesteatoma
It can also be used to treat patients with inadequate conductive hearing from previous middle ear surgery.
Stapes implant
The stapesplasty prosthesis is indicated in cases of congenital or acquired defects of the stapes due to e.g.:
Otosclerosis
Congenital fixation of the stapes
Traumatic injury
Malformation of the ossicular chain/middle ear
It can also be used to treat patients with inadequate conductive hearing from previous stapes surgery.
See also
Ossicular replacement prosthesis
References
Medical technology | Middle ear implant | [
"Biology"
] | 1,310 | [
"Medical technology"
] |
69,503,734 | https://en.wikipedia.org/wiki/Alexander%20Boldyrev | Alexander I. Boldyrev (December 19, 1951 - August 26, 2023) was a Russian-American computational chemist and R. Gaurth Hansen Professor at Utah State University. Professor Boldyrev is known for his pioneering works on superhalogens, superalkalis, tetracoordinated planar carbon, inorganic double helix, boron and aluminum clusters, and chemical bonding theory, especially aromaticity/antiaromaticity in all-metal structures, and development of the Adaptive Natural Density Partitioning (AdNDP) method.
Biography and Education
Alexander Boldyrev was born in the industrial Siberian city Novokuznetsk. After graduation from Specialized Educational Scientific Center at Novosibirsk University located in Siberian Akademgorodok, he was admitted to the Department of Chemistry at Novosibirsk University. While pursuing the B.Sc./M.Sc. degree, Alexander Boldyrev was doing his research at the Institute of Catalysis, USSR Academy of Sciences under Dr. Vasily Avdeev supervision. During this time, Alexander Boldyrev first encountered quantum-chemical calculations which shaped his further scientific career. After graduation from the university, he moved to another academic city, Chernogolovka, and joined Dr. Oleg Charkin's group when he worked on Non-rigid molecules and polytopic bonds. Later, he extended this study to his Ph.D. thesis which he defended in 1978. Following years, Dr. Boldyrev spent studying superhalogens and superallakis in Chernogolovka.
In 1983, Alexander joined Prof. Ovchinnikov lab at the Institute of Chemical Physics, USSR Academy of Science. In 1986, he received a Doctor of Science degree, the highest scientific degree in the USSR. In 1990, Dr. Boldyrev left USSR to join Paul von Ragué Schleyer group in Germany as a postdoc. There, he made a contribution to the theoretical chemistry of planar tetracoordinate carbon.
Further, Dr. Boldyrev moved to the United States where he worked for 7 year in Prof. Jack Simons research group. His research spanned hypervalent (“Rydberg”) molecules and stability of multiply charged anions (SO42−, PO43-) and their solvated forms. In 1999, Dr. Boldyrev became an assistant professor at Utah State University. Six years later, Alexander I. Boldyrev became a Full Professor, and in 2020 was awarded the R. Gaurth Hansen Professorship.
Research
During his academic career, Alexander Boldyrev worked on a wide range of topics related to quantum chemistry and physical chemistry. His works together with Paul von Ragué Schleyer were among the prediction of new way to achieve planar tetracoordinated carbon and participated in the first experimental conformation of such species in molecular beams with Prof. Lai-Sheng Wang. Dr. Boldyrev and Dr. Gutsev also developed the theory of superhalogens – molecules with high Electron affinity exceeding 7 eV in some cases (while the Electron affinity of halogens are 3-3.6 eV). In analogy to superhalogens, Boldyrev and Gutsev introduced superalkalis, species with extremely low Ionization potential, lower than that of a Caesium atom. Alexander Boldyrev together with Lai-Sheng Wang made a large contribution to the theory of chemical bonding, especially in the topic of Aromaticity and Antiaromaticity.
Adaptive Natural Density Partitioning Algorithm
The Adaptive Natural Density Partitioning Algorithm (AdNDP) is a theoretical tool for deciphering chemical bonding. It is generally applicable to any chemical system including molecules, clusters, mechanically bonded structures and solvated species. The algorithm was developed in 2008 by Dmitry Zubarev and Alexander Boldyrev. The AdNDP is based on the concept of occupancies of multicenter bonds. Thus, it represents the electronic structure in terms of n-center two-electron (nc-2e) bonds. AdNDP recovers both Lewis bonding elements (1c-2e and 2c-2e elements, corresponding to the lone pairs and two-center two-electron bonds, respectively) and deslocalized bonding elements, which are associated with the concepts of aromaticity and antiaromaticity. From this point of view, AdNDP achieves a seamless description of systems featuring both localized and delocalized bonding without invoking the concept of resonance (although, AdNDP is also capable of providing resonance structures). Essentially, AdNDP is a very efficient and illustrative approach for interpretation of the molecular orbital-based wave functions. AdNDP is closely related to Natural bond orbital theory but allows any number of atoms to participate in bond localization.
In 2013, a Solid State Adaptive Natural Density Partitioning (SSAdNDP), an extension of AdNDP, was introduced by Timur Galeev and Alexander Boldyrev in collaboration with Benjamin D. Dunnington and J. R. Schmidt. The algorithm enables the application of AdNDP formalism to periodic systems. As in the original AdNDP algorithm, SSAdNDP allows the interpretation of chemical bonding in systems with translational symmetry in terms of classical lone pairs, two-center bonds, as well as multi-center delocalized bonding elements.
Honors and awards
Alexander von Humboldt Fellowship, Germany, January 1990 - December 1992.
The Utah State College of Science Researcher of the Year for 2005.
The D. Wynne Thorne Career Research Award for 2009 at Utah State University.
The 2008 American Chemical Society Utah Award in Chemistry.
Fulbright Scholarship, September 1 – November 30, 2012, Comenius University, Bratislava, Slovak Republic.
Alexander von Humboldt Alumni Award, March 1 – May 31, 2013, Marburg University, Marburg, Germany.
The University Outstanding Graduate Mentor for 2017. Office of Research and Graduate Studies, Utah State University, March 21, 2017, USU.
The R. Gaurth Hansen Professor, November 2020 - November 2023, Department of Chemistry and Biochemistry, Utah State University.
American Association for the Advancement of Science Fellow, January 2022
Selected publications
“DVM-Xa Calculations on the Ionization Potentials of [MXk+1]− Complex Anions and the Electron Affinities of MXk+1 "Superhalogens"” G. L. Gutsev and A. I. Boldyrev, Chem. Phys., 56, 277, (1981).
“DVM-Xa Calculations on the Electronic Structure of "Superalkali" Cations” G. L. Gutsev and A. I. Boldyrev, Chem. Phys. Lett., 92, 262 (1982).
“Tetracoordinate Planar Carbon in the Al4C− Anion. A Combined Photoelectron Spectroscopy and Ab Initio Study.” X. Li, W. Chen, L. S. Wang, A. I. Boldyrev, and J. Simons, J. Am Chem. Soc., 121, 6033 (1999).
“Observation of All-Metal Aromatic Molecules.” X. Li, A.E. Kuznetsov, H.-F. Zhang, A.I. Boldyrev, L. S. Wang, Science, 291, 859-861 (2001).
“All-Metal Antiaromatic Molecule: Rectangular Al44- in the Li3Al4− Anion”, A.E. Kuznetsov, K.A. Birch, A.I. Boldyrev, X. Li, H.-J. Zhai, L. S. Wang, Science, 300, 622 (2003).
“Hepta- and Octacoordinated Boron in Molecular Wheels of Eight- and Nine-Atom Boron Clusters: Observation and Confirmation.” H.-J. Zhai, A. N. Alexandrova, K. A. Birch, A. I. Boldyrev, L. S. Wang, Angew. Chem. Int. Ed., 42, 6004–6008, (2003).
“Developing paradigms of chemical bonding: adaptive natural density partitioning” D. Yu. Zubarev, A. I. Boldyrev, Phys. Chem. Chem. Phys., 10, 5207–5217, (2008).
“A concentric planar doubly π-aromatic B19− cluster”, Wei Huang, Alina P. Sergeeva, Hua-Jin Zhai, Boris B. Averkiev, Lai-Sheng Wang, Alexander I. Boldyrev, Nat. Chem., 2, 202–206, (2010).
References
Computational chemistry
Utah State University faculty
Novosibirsk State University alumni
Computational chemists
1951 births
Living people | Alexander Boldyrev | [
"Chemistry"
] | 1,844 | [
"Theoretical chemistry",
"Computational chemistry",
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69,506,333 | https://en.wikipedia.org/wiki/Telefunken%20FuBK | The Telefunken FuBK (from the German Funkbetriebskommission for "Television Service Commission") is an electronic analogue television test card developed by AEG-Telefunken and Bosch Fernseh in West Germany as the successor to the monochrome T05 test card in the late-1960s and used with analogue 625-lines PAL broadcasts.
Not as popular as the Philips PM5544, nevertheless it saw widespread use in West Germany (and later reunified Germany) and some other European, Asian, South American and African countries, and by a few commercial TV stations in Australia.
Physical equipment
The test card was generated electronically by several video-signal generators, including two variations of the Philips PM5644 generator (PM5644G/50 {PAL B/G} and PM5644G/70 {YCbCr}) and the Rohde & Schwarz SGPF-B3 (the Grundig VG 1001 test signal generator has a different pattern design, but is sometimes indicated as "FuBk" because it features similar test elements). It has also been used in conjunction with digital broadcasts by means of the PT5300 from ProTeleVision/DK Technologies.
Test card features
Some elements present on the FuBK test card are:
Cross hatch - makes up the background of the table, with 19x15 white lines over a dark gray (25% luminance) background, allowing adjustment of CRT convergence and focus;
Circle - provide a way to correct vertical and horizontal raster scan geometrical distortions;
Colour bars - EBU colour bars at 75% luminance (75/0/75/0) to adjust colour saturation and purity
Grey staircase - five bars (0%, 25%, 50%, 75%, 100%) that allow setting brightness, linearity and contrast control
2T convergence cross - check for signal reflections and group delay, help with geometrical image centring
Multiburst- four grating with sine curves at 1, 2, 3 and 4.433 MHz, as a test of horizontal resolution
Black section- check for reflections, transient response and group delay
±V/ +U ramp - two lines that allow checking PAL decoder linearity with UV signals
+V/ ±U anti PAL - two achromatic fields to test the PAL decoder delay line
On PAL broadcasts, with a maximum displayable video bandwidth of around 5 MHz, individual lines should just be visible in all Multiburst gratings. In other situations, like a VHS recording with reduced bandwidth, they become more and more indistinct, merging into a grey area.
The two special achromatic fields should be displayed as grey if PAL decoding is functioning correctly. If not, colour will be seen on these areas, as shown in the off-air screen capture of ARD Das Erste test card, visible on the "Usage Gallery" at the end of this article.
Variations
4:3
A variation (used by Doordarshan in India, by PTT-NL/Nozema/NOS in the Netherlands, TVR in Romania, YLE in Finland, Sky One in the United Kingdom and in West Germany) simply omitted the centre circle. This variation is also anecdotally called "Simplified FuBK".
Another variation adds a second set of colour bars (replacing the ±V/ +U Ramp and +V/ ±U Anti PAL sections) and flips the middle downward triangle. This was used by IRIB in Iran.
Another variation that adds border castellations and changes the middle downward triangle to a simple vertical bar, used by Kanal 2 in Denmark, Rupavahini in Sri Lanka, Televerket Kabel-TV in Sweden and on some German channels. Used with further modifications and added graphics by al-Jamahiriya TV (Libya).
Another modification, again omitting the circle but including a grid cross in the middle and slightly different resolution gratings, was known to be used on some TV transmitters in Belgium and the Netherlands.
A monochrome variant, omitting the centre circle and replacing the colour bars with a black box showing the transmitter name and channel, as well as an on-screen line gauge replacing the ±V/ +U Ramp and +V/ ±U Anti PAL sections near the bottom, was used on some DBP-operated TV transmitters in West Germany in the 1970s.
While not exactly a variant, the Grundig VG 1001 pattern features many of the FuBK test elements, like the colour and grey bars, PAL check area and gratings. This allows it to be used to perform the same adjustments. This pattern was used by a few channels like BRT (Flemish Community of Belgium), SDR (southwest Germany), Polsat (Poland), MVQ-6 (Mackay Region, QLD, Australia), at the headends of many Finnish cable TV providers, on experimental satellite test transmissions involving the Orbital Test Satellite in the early-1980s, as well as on point-to-point cable and satellite feeds in the UK, France, Austria, Italy, Germany, Luxembourg and Belgium. A heavily modified version of the VG 1001 pattern was used for SECAM transmissions by Bulgarian National Television (BNT) during People's Republic of Bulgaria era and also later in PAL by NOVA from its launch in 1994.
16:9
In the 1990s, a FuBK variant in the 16:9 aspect ratio format was developed for the PALplus and (HD-)MAC standards and was used by some channels such as ARD. Crosshatch was changed to a 25x15 grid, and geometric markings for the central 4:3 safe area were included, with the other details being generally the same as on the original version. This pattern could be generated by the Grundig VG 1100 video generator, introduced around 1995 as well as the PM5644/86 and the digital PT5300 from DK Technologies (with an optional hardware upgrade).
Variation Gallery
Usage
This pattern was used by many broadcasters, including:
ARD and ZDF (Germany, ARD also used the 16:9 variation)
Norddeutscher Rundfunk (NDR Fernsehen; Northern German Broadcasting Hamburg)
Westdeutscher Rundfunk (WDR Fernsehen; West German Broadcasting Cologne)
Südwestrundfunk (SWR Fernsehen; southwest Germany)
Deutsche Bundespost, Deutsche Telekom and T-Systems (Germany)
Hessischer Rundfunk (hr-fernsehen, Germany)
Kabel Deutschland and Premiere (Germany)
Hrvatska radiotelevizija (Croatian Radiotelevision)
Argentina Televisora Color, Telefe (Argentina)
Rupavahini (Sri Lanka)
RTL9 (Luxembourg)
Rádio e Televisão de Portugal (RTP; Portuguese public broadcasting corporation)
Islamic Republic of Iran Broadcasting (IRIB; used a variation of the pattern)
RTL-TVI and VT4 (Belgium)
Canal+ (Belgium; used a modification of the pattern with grid cross)
NRK (Norwegian Broadcasting Corporation)
YLE, Kolmoskanava, MTV3 and Nelonen (Finland)
Yugoslav Radio Television (RTV Zagreb, Sarajevo)
SRG SSR (SF, TSR, TSI); Teleclub (Switzerland)
Doordarshan (Indian public television broadcaster; 4:3 version without circle)
BTV6 and GTV9 in Australia
Channel 5 and Channel 7 (Thailand)
Magyar Televízió (Hungarian public television broadcaster; replaced Philips PM5544 from 2009)
Alfa TV Budapest, TV2 Hungary
NPO 1, NPO 2, NPO 3 (Netherlands)
Nozema and Staatsbedrijf der Posterijen, Telegrafie en Telefonie (Netherlands)
Televiziunea Română (Romanian public television broadcaster; with and without circle)
Czechoslovak Television
ERTT (Tunisia)
M-Net and e.tv (South Africa)
al-Jamahiriya TV (Libya; original and modified versions)
Kanal 2 and TV 2 Zulu (Denmark)
Channel One Russia (Grundig VG 1100 variant; used from June 1, 2011 until January 31, 2023)
TVRI from 1974 until 31 December 1984, TPI from 1991 until early-2000 (Indonesia)
Televerket Kabel-TV (Sweden)
Sky One (United Kingdom)
Warszawska Telewizja Kablowa „Porion” (Poland)
Usage Gallery
Cultural references
The Telefunken FuBK test card is featured in the 2016 Finnish indie video game My Summer Car, which the player's television sets in his house and in the in-game town's jail would show during the in-game overnight broadcast break. This was done to mimic the Finnish public broadcaster YLE's test card, which was used from the 1970s until the 2000s.
See also
Philips PM5544
ETP-1
Test card
References
Test cards
Broadcast engineering | Telefunken FuBK | [
"Engineering"
] | 1,868 | [
"Broadcast engineering",
"Electronic engineering"
] |
69,506,742 | https://en.wikipedia.org/wiki/Hycean%20planet | A hycean planet ( ) is a hypothetical type of exoplanet that features a liquid water ocean underneath a hydrogen-rich atmosphere. The term hycean is a portmanteau of hydrogen and ocean.
Definition
A hycean planet is a hypothetical type of planet with liquid water oceans under a hydrogen atmosphere. The presence of extraterrestrial liquid water makes hycean planets regarded as promising candidates for planetary habitability. They are usually considered to be larger and more massive than Earth. As of 2023, there are no confirmed hycean planets, but the Kepler mission detected many candidates.
History
The term "hycean planet" was coined in 2021 by a team of exoplanet researchers at the University of Cambridge, as a portmanteau of "hydrogen" and "ocean," used to describe planets that are thought to have large oceans and hydrogen-rich atmospheres. Hycean planets are thought to be common around red dwarf stars, and are considered to be a promising place to search for life beyond Earth. The term was first used in a paper published in The Astrophysical Journal on August 31, 2021.
Life on hycean planets would probably be entirely aquatic. Their water-rich compositions imply that they can have larger sizes than comparable non-hycean planets, thus making detection of biosignatures easier. Hycean worlds could be investigated for biosignatures by terrestrial telescopes and space telescopes like the James Webb Space Telescope (JWST). In 2023, the JWST investigated K2-18b and found evidence for both a hycean atmosphere and the presence of dimethyl sulfide ─ a potential biosignature.
Properties
Hycean planets could be considerably larger than previous estimates for habitable planets, with radii reaching () and masses of (). Moreover, the habitable zone of such planets could be considerably larger than that of Earth-like planets. The planetary equilibrium temperature can reach for planets orbiting late M-dwarfs. However, mass and radius do not by themselves inform the composition of a planet, as bodies with identical mass and radius can have distinct compositions: A given planet may thus be either a hycean planet or a super-Earth.
Such planets can have many distinct atmospheric compositions and internal structures. Also possible are tidally locked "dark hycean" planets (habitable only on the side of permanent night) or "cold hycean" planets (with negligible irradiation, being kept warm by the greenhouse effect). Dark hycean worlds can form when the atmosphere does not effectively transport heat from the permanent day side to the permanent night side, thus the night side has temperate temperatures while the day side is too hot for life. Cold hycean planets may exist even in the absence of stars, e.g. rogue planets.
Although the presence of water may help them be habitable planets, their habitability may be limited by a possible runaway greenhouse effect. Hydrogen reacts differently to starlight's wavelengths than do heavier gases like nitrogen and oxygen. If the planet orbits a sun-like star at one Astronomical unit (AU), the temperature would be so high that the oceans would boil and water would become vapor. Current calculations locate the habitable zone where water would remain liquid at 1.6 AU, if the atmospheric pressure is similar to Earth's, or at 3.85 AU if it is the more likely tenfold to twentyfold pressure. All current hycean planet candidates are located within the area where oceans would boil, and are thus unlikely to have actual oceans of liquid water. Another limiting factor is that X-ray and UV radiation from the star (especially active stars) can destroy the water molecules.
Features
They are regarded to be covered in oceans.
They have hydrogen-rich atmospheres. The atmospheres on hycean planets are thought to be made up of hydrogen, helium, and water vapor.
Dark hycean planets thought to be common around red dwarf stars. Red dwarf stars are the most common type of star in the Milky Way galaxy.
They are considered to be a promising place to search for life beyond Earth. Hycean planets have the ingredients that is necessary for life, including liquid water, energy, and organic molecules.
Their atmospheres may have less methane and ammonia than comparable non-hycean Neptune-like planets, if they have water oceans.
They might have a much higher free energy availability for their ecosystems than Earth.
Hycean planets may be capable of supporting extraterrestrial life, despite their properties differing drastically from Earth's. Astronomers plan to use telescopes like the James Webb Space Telescope to search for hycean planets and to learn more about their potential for habitability.
Candidates
K2-18b
One such candidate planet is K2-18b, which orbits a faint star with a period of about 33 days. This candidate planet could have liquid water, containing a considerable high amount of hydrogen gas in its atmosphere, and is far enough from its star, such that it resides within its star's habitable zone. Such candidate planets can be studied for biomarkers.
In 2023, the James Webb Space Telescope detected carbon dioxide and methane in the atmosphere of K2-18b, but it did not detect large amounts of ammonia. This supports the hypothesis that K2-18b could indeed have a water ocean. The same observations also suggest that K2-18b's atmosphere might contain dimethyl sulfide, a compound associated with life on Earth, although this has yet to be confirmed. Another possibility is that K2-18b is a lava world with a hydrogen atmosphere.
Other candidates
K2-3b, a potential Dark hycean planet but may be too hot.
K2-3c but may be too hot.
Kepler-138d
LTT 1445 A b but may be too hot and too water-poor.
TOI-732 c but may be too hot.
TOI-1266 c but may be too hot.
TOI-175 d but may be too hot.
TOI-2136 b
TOI-270 c, a potential Dark hycean planet but may be too hot.
TOI-270 d but may be too hot.
TOI-776 b, a potential Dark hycean planet but may be too hot.
TOI-776 c but may be too hot.
See also
Hot Neptune
Exoplanet
Ocean world
References
Sources
External links
Types of planet
Hypothetical astronomical objects
Extraterrestrial water
2021 neologisms
2021 in science | Hycean planet | [
"Astronomy"
] | 1,349 | [
"Astronomical hypotheses",
"Hypothetical astronomical objects",
"Astronomical myths",
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69,509,078 | https://en.wikipedia.org/wiki/HPC5 | HPC5 is a supercomputer built by Dell and installed by Eni, capable of 51.721 petaflops, and is ranked 9th in the Top500 as of November 2021. It is located in the Green Data Center in Ferrera Erbognone, in Northern Italy. In June 2020, HPC5 ranked 6th in the Green500. HPC5 is an upgrade to the HPC4 system, which was built by Hewlett Packard Enterprise and used by Eni. It is also called as HPC4+.
HPC5 spans over 1,820 Dell EMC PowerEdge C4140 servers, each with two Intel Gold 6252 24-core processors and four Nvidia V100 GPU accelerators. In total, the system comprises 7,280 NVIDIA V100 GPUs.
See also
Supercomputing in Europe
Top500
Green500
References
External links
Official Eni website
Supercomputing in Europe | HPC5 | [
"Technology"
] | 199 | [
"Supercomputing in Europe",
"Computing stubs",
"Supercomputing",
"Computer hardware stubs"
] |
69,509,977 | https://en.wikipedia.org/wiki/Neodymium%20phosphide | Neodymium phosphide is an inorganic compound of neodymium and phosphorus with the chemical formula NdP.
Preparation
Neodymium phosphide can be obtained by reacting neodymium and phosphorus in a stoichiometric ratio:
4Nd + P4 -> 4NdP
Physical properties
Neodymium phosphide forms cubic crystals, space group Fmm, cell parameters a = 0.5838 nm, Z = 4.
Uses
The compound is a semiconductor used in high power, high frequency applications, and in laser diodes.
References
Phosphides
Neodymium(III) compounds
Semiconductors
Rock salt crystal structure | Neodymium phosphide | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
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69,512,845 | https://en.wikipedia.org/wiki/420%20Main | The 420 Main Building (previously known as Old National Bank Tower) was a 248-foot, 18-story office building located at 420 Main Street in downtown Evansville, Indiana. The building was the headquarters of the Old National Bank until the bank moved its headquarters to a new location in 2004. The building stood nearly vacant for the next 12 years, and was the tallest building in the city until its demolition in 2021.
History
The building was built as the new headquarters for Old National Bank, serving as a replacement for the Hotel Lincoln and ONB building built in 1916, the previous headquarters of Old National Bank. The ceremonial groundbreaking for the building site took place on December 15, 1967, and foundation work commenced in 1968. A topping out ceremony was held on May 24, 1969, and the building was completed in 1970.
In 2004, the bank moved its headquarters to the new Old National Place, located on One Main Street by the Ohio River riverfront. As a result, the building stood nearly vacant for the next 12 years. In 2015, the building went up for sale.
In 2017, local developers planned a $25 million project to renovate the building that would involve street-level retail, offices, and apartments on the upper floors of the building. However, this project was later abandoned.
In October 2019, the building was purchased by Domo Development, and plans were to redevelop the building into a mixed-use tower that would include a restaurant, retail, office, and residential space. The full renovation would have included a new glass curtain wall. The renovation cost was estimated to be $30 million.
In October 2020, Domo Development raised concerns about the cost of renovating the building and instead planned demolition. A residential mixed-use complex is being proposed as a replacement.
Closure and demolition
After years of disrepair and prohibitive costs to renovate the building, the building was demolished via implosion on the morning of November 21, 2021 at 7:00 AM, by Controlled Demolition, Inc.
References
1970 establishments in Indiana
2021 disestablishments in Indiana
Buildings and structures in Evansville, Indiana
Buildings and structures demolished by controlled implosion
Demolished buildings and structures in Indiana
Buildings and structures demolished in 2021
Office buildings completed in 1970
Former skyscrapers | 420 Main | [
"Engineering"
] | 459 | [
"Buildings and structures demolished by controlled implosion",
"Architecture"
] |
69,512,913 | https://en.wikipedia.org/wiki/Livestreaming%20e-commerce%20in%20China | Livestreaming e-commerce in China (also known as live commerce or livestream shopping; ) was initiated by fashion e-commerce platform Mogujie in 2016. In the same year, it was picked up and gradually made popular by Alibaba, who turned live commerce into a fixture in its annual Singles' Day shopping festivals.
Market size in China
After a three-year development period between 2016 and 2018, China’s livestreaming e-commerce industry became popular in 2019. Today, it is a well-established ecosystem which in 2020 counted over 8,800 companies and 1.23 million live hosts, known in China as Key Opinion Leaders (KOLs), according to Shanghai-based new retail research firm iResearch. In 2020, the top two KOL, Austin Li and Viya, alone, sold 9.1 Million RMB in Alibaba's Single's Day pre-sale.
According to the 47th Statistical Report on China’s Internet Development, released in February 2021 by China Internet Network Information Center (CNNIC), the number of livestream e-commerce users was 388 million by 2020, accounting for roughly 40% of the Chinese internet population.
The industry exceeded the one-trillion RMB threshold by the end of 2020, according to KPMG and AliResearch. While the growth of the sector is diminishing year after year, China’s live commerce market is forecast to continue growing. From 31 March 2020 to 31 March 2021, GMV on Taobao Live was 6.7% of the total transaction volume for Alibaba’s online marketplaces in China. In 2020, live commerce accounted for 10.6% of the country’s total online retail market.
The livestreaming trend has particularly benefited sales of agricultural products through e-commerce, with streamers presenting live tastings.
The rapid expansion of China's live streaming e-commerce industry has dramatically changed consumer buying behavior. The main reason is that the interactive nature of live streaming enhances consumer trust and engagement. At the same time, live e-commerce has promoted and influenced consumers' shopping willingness through vivid price attraction.
Chinese platforms for live commerce
The main Chinese platforms for live commerce are, according to Pandaily:
Taobao Live – the live streaming platform of Alibaba’s B2C platform Taobao, one of the earliest adopters of live e-commerce in China.
Kuaishou – a mobile app for short videos, particularly popular among the lower tier cities and rural areas.
Douyin – the short-video platform owned by ByteDance and famous outside of China as TikTok.
Multi-channel networks in China
Besides the livestream platforms, the growth of the industry is fueled by multi-channel networks (MCNs), companies who incubate live streamers, or KOLs, and connect them with brands and end-users. MCN plays two critical roles. On the one hand, MCNs are training live streamers and acting as a communication bridge between merchants and live streamers. Based on the merchant's product information, the MCN selects the suitable live streamers they have trained to prepare for live streaming sales to sell their products. In addition, the MCN will negotiate details with the merchant on behalf of the live streamer, such as deposits, commissions, and products to be sold. Most MCNs have one leading KOL in the founding team or as the main source of revenue, and tend to work with one platform. Among the most famous MCNs in China are, according to TechNode:
Regulatory interventions
In March 2021, the State Administration for Market Regulation introduced new rules targeting the development of the livestreaming e-commerce sector, giving platforms and merchants more responsibilities and addressing concerns linked to user data privacy and forced exclusivity.
In April 2021, six Chinese government agencies including the Cyberspace Administration of China rolled out additional rules requiring providers to set up a system to maintain the safety of content, verify the identity of livestream hosts and to secure users' personal information.
In August 2021, China’s Ministry of Commerce introduced new industry standards for livestream commerce, detailing how hosts should dress or speak during the live broadcasts, as well as setting guidelines for hosts and products reviews.
References
E-commerce in China
Streaming
Non-store retailing
Retailing in China | Livestreaming e-commerce in China | [
"Technology"
] | 892 | [
"Multimedia",
"Streaming"
] |
69,512,965 | https://en.wikipedia.org/wiki/V1936%20Aquilae | V1936 Aquilae is a blue supergiant and candidate Luminous blue variable located in the nebula Westerhout 51, in the constellation Aquila, about 20,000 light years away. The star was originally identified as a massive star in 2000, and was thought to be an O-type supergiant. However, subsequent analyses have shown it to be not O but B-type, as well as being possibly an LBV. The star was shown to be a variable star by Luboš Kohoutek and R. Wehmeyer in 2004.
Properties
V1936 Aquilae is a very luminous star. Recent measurements hint at a bolometric luminosity of around , assuming a distance of 6 kiloparsecs, consistent with the distance of Westerhout 51, the very large H II region (nebula) it is located in. The star likely has a temperature of around . The Stefan-Boltzmann Law suggests a radius of around 143 times that of the Sun.
References
Aquila (constellation)
Luminous blue variables
Aquilae, V1936
O-type supergiants | V1936 Aquilae | [
"Astronomy"
] | 234 | [
"Aquila (constellation)",
"Constellations"
] |
69,512,983 | https://en.wikipedia.org/wiki/School%20of%20Molecular%20Sciences | The School of Molecular Sciences is an academic unit of The College of Liberal Arts and Sciences at Arizona State University (ASU). The School of Molecular Sciences (SMS) is responsible for the study and teaching of the academic disciplines of chemistry and biochemistry at ASU.
History
Chemistry instruction at ASU can be traced back to the early 1890s. At that time, the educational institution, a Normal School for the Territory of Arizona, “acquired...a supply of chemicals” for instructional purposes. Chemistry classes were held in Old Main during the late 1800s and into the early 1900s, taught by Frederick M. Irish.
In 1927, President Arthur John Matthews hired George Bateman, the first faculty to hold a PhD who was not also a principal or president of the school. Bateman taught chemistry classes, among other things, for forty years. He oversaw the development of the physical sciences at ASU, including new science facilities and degrees.
In 1946, new majors leading to degrees were added, including Physical and Biological Science. In 1947 the State of AZ designated $525,000 for a new science building.
In 1953 the first college, the College of Arts and Sciences was established with 14 departments. In 1954 Arizona State College was restructured into 4 colleges, which went into effect in the 1955–56 academic year: the College of Liberal Arts, the College of Education, the College of Applied Arts and Sciences, and the College of Business and Public Administration.
In 1957, the Department of Chemistry first appeared in the Arizona State College Bulletin (Vol. LXXII No. 2, April 1957), listed under the Division of Physical Sciences. Early chemists, such as LeRoy Eyring helped build ASU's strong science reputation; Roland K. Robins conducted cancer research as early as 1957.
In 1958, Arizona State College was renamed Arizona State University. Chemistry was the first department to be approved to offer a doctoral degree.
In 1960, George Boyd, the university's first coordinator of research, helped secure a portion of Harvey H. Nininger’s meteorites for ASU, making it the largest university-based meteorite collection in the world.
In 1961, Geochemist Carleton B. Moore became the first director of the Center for Meteorite Studies, which at the time was housed in the Department of Chemistry.
In 1963, Peter R. Buseck, who pioneered high-resolution transmission electron microscopy (TEM) research on meteorites and terrestrial minerals.
In 1963, ASU awarded its first doctoral degrees to four students, one of whom, Jesse W. Jones, was the first Chemistry PhD of ASU and the first African American to earn a PhD at ASU. Jones went on to teach chemistry at Baylor University for over 30 years.
In 1965 Robert Pettit was hired and began developing marine-organism research that led to the creation of anti-cancer drugs and, in 1973, what became the Cancer Research Institute. Pettit taught at ASU until his retirement in 2021.
In 1967, George Bateman, after enjoying a productive forty-year career at ASU, retired. The Bateman Physical Sciences Complex was named to honor his many contributions and years of service in 1977.
In 1992 the Department of Chemistry was renamed the Department of Chemistry and Biochemistry.
In 2015 the department became the School of Molecular Sciences to recognize the fact that modern chemical science has impact well beyond the traditional disciplinary boundaries of chemistry and biochemistry. Rather than being discipline-based, the school's mission is to tackle important societal problems in medicine, technology, energy and the environment from an atomic and molecular perspective.
Chairs and Directors
George Bateman (1957–1961)
LeRoy Eyring (1961–1969)
Therald Moeller (1969–1975)
Morton Munk (1975–1986)
William Glaunsinger (1986–1989)
Morton Munk (1989–1998)
Devens Gust (1998–2002)
Robert Blankenship (2002–2006)
William Petuskey (2006–2012)
Daniel Buttry (2012–2016)
Neal Woodbury (2016–2019)
Ian Gould (2019–2021)
Tijana Rajh (2021–present)
Location
The administrative offices of the School of Molecular Sciences are located within the Bateman Science Complex on ASU's Tempe campus. Faculty labs are located in the Bateman Complex, in the Biodesign Institute, and the ISTB1 and ISTB5 buildings.
Research
Research in the School of Molecular Sciences is organized around six themes:
Materials and Nanoscience
Medicine and Health
Energy and Sustainability
Chemistry of Biology
Environmental and Biogeochemistry
Fundamental Molecular Science
Scientific Firsts
In 1969 the first measurements of carbon in Apollo Mission lunar-return samples were obtained by Carleton Moore and Charles Lewis.
In 1970 the first extraterrestrial amino acids were detected by Carleton Moore in the Murchison meteorite.
In 1975 the first quantitative chemical analyses of individual atmospheric aerosol particles was done by Peter Buseck using an electron microprobe.
In 1999 the first images of atomic orbitals were obtained from a combined electron diffraction and X-Ray diffraction study of the mineral cuprite, Cu2O, by Michael O’Keeffe and John Spence of the Department of Physics at ASU.
The first MOFs were designed and synthesized by Michael O’Keeffe and Omar Yagi, who at the time was an assistant professor of chemistry and biochemistry at ASU, opening the field of reticular chemistry.
Petra Fromme's group was part of the team that generated the first crystal structure of a protein using the X-Ray free electron laser method.
In 2017 the first fully biochemistry degree in the nation were launched by the School of Molecular Sciences, including innovative hands-on lab courses, followed in 2020 by the first fully online chemistry degree in the nation.
Notable Current and Former Faculty Members
Michael O’Keeffe
Omar Yaghi
Alex Navrotsky
Austen Angell
George "Bob" Pettit
Carleton B. Moore
Peter R. Buseck
Notable alumni
Jesse W. Jones was the first chemistry PhD and earned one of the first four doctorate degrees awarded by Arizona State University in 1963. He is a tenured Professor of Chemistry at Baylor University since 1988 and served seven two-year terms as a State Representative of Texas. In 2012 he was inducted into the African American Education Archives & History Program Hall of Fame.
Spencer Silver graduated from ASU in 1962. He was a chemist and inventor who specialized in adhesives; he is credited by 3M for creating the adhesive that is used on Post-It Notes.
Ed Pastor received his Bachelor of Arts degree in chemistry from ASU. He served as a member of the United States House of Representatives for the state of Arizona from 1991 to 2015.
Cheryl Shavers, who grew up in South Phoenix, earned both undergraduate and PhD degrees in chemistry. She subsequently worked for Motorola, Hewlett Packard, and Intel, then became Under Secretary of Commerce and Technology (1999–2001) in the Clinton administration. She was inducted into the Women in Technology International (WITI) Hall of Fame, and the Hall of Fame of ASU's College of Liberal Arts and Sciences.
Jeffrey Post earn his PhD from ASU in (date needed) and serves as the Mineralogist and Curator-in-Charge of Gems and Minerals at the National Museum of Natural History, the home of the Hope Diamond.
Laurie Leshin, Director of the NASA Jet Propulsion Laboratory, earned her bachelor's in chemistry in 1987.
References
External links
Official Website
Arizona State University
Chemistry
Biochemistry | School of Molecular Sciences | [
"Chemistry",
"Biology"
] | 1,534 | [
"Biochemistry",
"nan"
] |
69,513,035 | https://en.wikipedia.org/wiki/Container%20method | The method of (hypergraph) containers is a powerful tool that can help characterize the typical structure and/or answer extremal questions about families of discrete objects with a prescribed set of local constraints. Such questions arise naturally in extremal graph theory, additive combinatorics, discrete geometry, coding theory, and Ramsey theory; they include some of the most classical problems in the associated fields.
These problems can be expressed as questions of the following form: given a hypergraph on finite vertex set with edge set (i.e. a collection of subsets of with some size constraints), what can we say about the independent sets of (i.e. those subsets of that contain no element of )? The hypergraph container lemma provides a method for tackling such questions.
History
One of the foundational problems of extremal graph theory, dating to work of Mantel in 1907 and Turán from the 1940s, asks to characterize those graphs that do not contain a copy of some fixed forbidden as a subgraph. In a different domain, one of the motivating questions in additive combinatorics is understanding how large a set of integers can be without containing a -term arithmetic progression, with upper bounds on this size given by Roth () and Szemerédi (general ).
The method of containers (in graphs) was initially pioneered by Kleitman and Winston in 1980, who bounded the number of lattices and graphs without 4-cycles. Container-style lemmas were independently developed by multiple mathematicians in different contexts, notably including Sapozhenko, who initially used this approach in 2002-2003 to enumerate independent sets in regular graphs, sum-free sets in abelian groups, and study a variety of other enumeration problems
A generalization of these ideas to a hypergraph container lemma was devised independently by Saxton and Thomason and Balogh, Morris, and Samotij in 2015, inspired by a variety of previous related work.
Main idea and informal statement
Many problems in combinatorics can be recast as questions about independent sets in graphs and hypergraphs. For example, suppose we wish to understand subsets of integers to , which we denote by that lack a -term arithmetic progression. These sets are exactly the independent sets in the -uniform hypergraph , where is the collection of all -term arithmetic progressions in .
In the above (and many other) instances, there are usually two natural classes of problems posed about a hypergraph :
What is the size of a maximum independent set in ? What does the collection of maximum-sized independent sets in look like?
How many independent sets does have? What does a "typical" independent set in look like?
These problems are connected by a simple observation. Let be the size of a largest independent set of and suppose has independent sets. Then,
where the lower bound follows by taking all subsets of a maximum independent set. These bounds are relatively far away from each other unless is very large, close to the number of vertices of the hypergraph. However, in many hypergraphs that naturally arise in combinatorial problems, we have reason to believe that the lower bound is closer to the true value; thus the primary goal is to improve the upper bounds on .
The hypergraph container lemma provides a powerful approach to understanding the structure and size of the family of independent sets in a hypergraph. At its core, the hypergraph container method enables us to extract from a hypergraph, a collection of containers, subsets of vertices that satisfy the following properties:
There are not too many containers.
Each container is not much larger than the largest independent set.
Each container has few edges.
Every independent set in the hypergraph is fully included in some container.
The name container alludes to this last condition. Such containers often provide an effective approach to characterizing the family of independent sets (subsets of the containers) and to enumerating the independent sets of a hypergraph (by simply considering all possible subsets of a container).
The hypergraph container lemma achieves the above container decomposition in two pieces. It constructs a deterministic function . Then, it provides an algorithm that extracts from each independent set in hypergraph , a relatively small collection of vertices , called a fingerprint, with the property that . Then, the containers are the collection of sets that arise in the above process, and the small size of the fingerprints provides good control on the number of such container sets.
Graph container algorithm
We first describe a method for showing strong upper bounds on the number of independent sets in a graph; this exposition is adapted from a survey of Samotij about the graph container method, originally employed by Kleitman-Winston and Sapozhenko.
Notation
We use the following notation in the below section.
is a graph on vertices, where the vertex set is equipped with (arbitrary) ordering .
Let be the collection of independent sets of with size . Let be the number of independent sets of size .
The max-degree ordering of a vertex subset is the ordering of the vertices in by their degree in the induced subgraph .
Kleitman-Winston algorithm
The following algorithm gives a small "fingerprint" for every independent set in a graph and a deterministic function of the fingerprint to construct a not-too-large subset that contains the entire independent set
Fix graph , independent set and positive integer .
Initialize: let .
Iterate for :
Construct the max-degree ordering of
Find the minimal index such that (i.e. the vertex in of largest degree in induced subgraph )
Let , where is the neighborhood of vertex .
Output the vector and the vertex set .
Analysis
By construction, the output of the above algorithm has property that , noting that is a vertex subset that is completely determined by and not otherwise a function of . To emphasize this we will write . We also observe that we can reconstruct the set in the above algorithm just from the vector .
This suggests that might be a good choice of a fingerprint and a good choice for a container. More precisely, we can bound the number of independent sets of of some size as a sum over output sequences
,
where we can sum across to get a bound on the total number of independent sets of the graph:
.
When trying to minimize this upper bound, we want to pick that balances/minimizes these two terms. This result illustrates the value of ordering vertices by maximum degree (to minimize ).
Lemmas
The above inequalities and observations can be stated in a more general setting, divorced from an explicit sum over vectors .
Lemma 1: Given a graph with and assume that integer and real numbers satisfy .
Suppose that every induced subgraph on at least vertices has edge density at least . Then for every integer ,
Lemma 2: Let be a graph on vertices and assume that an integer and reals are chosen such that . If all subsets of at least vertices have at least edges, then there is a collection of subsets of vertices ("fingerprints") and a deterministic function , so that for every independent set , there is such that .
Hypergraph container lemma
Informally, the hypergraph container lemma tells us that we can assign a small fingerprint to each independent set, so that all independent sets with the same fingerprint belong to the same larger set, , the associated container, that has size bounded away from the number of vertices of the hypergraph. Further, these fingerprints are small (and thus there are few containers), and we can upper bound their size in an essentially optimal way using some simple properties of the hypergraph.
We recall the following notation associated to uniform hypergraph .
Define for positive integers , where .
Let be the collection of independent sets of . will denote some such independent set.
Statement
We state the version of this lemma found in a work of Balogh, Morris, Samotij, and Saxton.
Let be a -uniform hypergraph and suppose that for every and some , we have that . Then, there is a collection and a function such that
for every there exists with and .
for every and .
Example applications
Regular graphs
Upper bound on the number of independent sets
We will show that there is an absolute constant such that every -vertex -regular graph satisfies .
We can bound the number of independent sets of each size by using the trivial bound for .
For larger , take With these parameters, -regular graph satisfies the conditions of Lemma 1 and thus,
Summing over all gives
,
which yields the desired result when we plug in
Sum-free sets
A set of elements of an abelian group is called sum-free if there are no satisfying . We will show that there are at most sum-free subsets of .
This will follow from our above bounds on the number of independent sets in a regular graph. To see this, we will need to construct an auxiliary graph. We first observe that up to lower order terms, we can restrict our focus to sum-free sets with at least elements smaller than (since the number of subsets in the complement of this is at most ).
Given some subset , we define an auxiliary graph with vertex set and edge set , and observe that our auxiliary graph is regular since each element of is smaller than . Then if are the smallest elements of subset , the set is an independent set in the graph . Then, by our previous bound, we see that the number of sum-free subsets of is at most
Triangle-free graphs
We give an illustration of using the hypergraph container lemma to answer an enumerative question by giving an asymptotically tight upper bound on the number of triangle-free graphs with vertices.
Informal statement
Since bipartite graphs are triangle-free, the number of triangle free graphs with vertices is at least , obtained by enumerating all possible subgraphs of the balanced complete bipartite graph .
We can construct an auxiliary -uniform hypergraph with vertex set and edge set . This hypergraph "encodes" triangles in the sense that the family of triangle-free graphs on vertices is exactly the collection of independent sets of this hypergraph, .
The above hypergraph has a nice degree distribution: each edge of , and thus vertex in is contained in exactly triangles and each pair of elements in is contained in at most 1 triangle. Therefore, applying the hypergraph container lemma (iteratively), we are able to show that there is a family of containers that each contain few triangles that contain every triangle-free graph/independent set of the hypergraph.
Upper bound on the number of triangle-free graphs
We first specialize the generic hypergraph container lemma to 3-uniform hypergraphs as follows:
Lemma: For every , there exists such that the following holds. Let be a 3-uniform hypergraph with average degree and suppose that . Then there exists a collection of at most containers such that
for every , there exists
for all
Applying this lemma iteratively will give the following theorem (as proved below):
Theorem: For all , there exists such that the following holds. For each positive integer , there exists a collection of graphs on vertices with such that
each has fewer than triangles,
each triangle-free graph on vertices is contained in some .
Proof: Consider the hypergraph defined above. As observed informally earlier, the hypergraph satisfies for every . Therefore, we can apply the above Lemma to with to find some collection of subsets of (i.e. graphs on vertices) such that
every triangle free graph is a subgraph of some ,
every has at most edges.
This is not quite as strong as the result we want to show, so we will iteratively apply the container lemma. Suppose we have some container with at least triangles. We can apply the container lemma to the induced sub-hypergraph . The average degree of is at least , since every triangle in is an edge in , and this induced subgraph has at most vertices. Thus, we can apply Lemma with parameter , remove from our set of containers, replacing it by this set of containers, the containers covering .
We can keep iterating until we have a final collection of containers that each contain fewer than triangles. We observe that this collection cannot be too big; all of our induced subgraphs have at most vertices and average degree at least , meaning that each iteration results in at most new containers. Further, the container size shrinks by a factor of each time, so after a bounded (depending on ) number of iterations, the iterative process will terminate.
See also
Independent set (graph theory)
Szemerédi's theorem
Szemerédi regularity lemma
References
Extremal graph theory
Hypergraphs
Additive combinatorics | Container method | [
"Mathematics"
] | 2,594 | [
"Additive combinatorics",
"Graph theory",
"Combinatorics",
"Mathematical relations",
"Extremal graph theory"
] |
69,513,046 | https://en.wikipedia.org/wiki/Capital%20Plaza%20Office%20Tower%20%28Frankfort%2C%20Kentucky%29 | The Capital Plaza Office Tower was a 338-foot tall, 28-story office skyscraper located at 500 Mero Street in Frankfort, Kentucky. It was the tallest building in Frankfort and the 11th tallest building in the state of Kentucky.
History
Construction for the tower started in 1968 and completed in 1972 as part of the Capital Plaza Project, which also included the Frankfort Convention Center and Fountain Place Shoppes. The building was designed by architect Edward Durrell Stone, who was also the architect for the Aon Center (then known as the Standard Oil Building) in Chicago, Illinois, and the General Motors Building in Manhattan, New York City. The Robert E. McKee Co. of Dallas Texas was general contractor.
The building mainly housed state government offices.
By the early 2000s, the Capital Plaza Complex had fallen into disrepair including the Capital Plaza Office Tower, with sections of the plaza being closed to pedestrians due to safety. In August 2008, a Lexington-based architecture firm and city officials recommended the demolition of the Capital Plaza Office Tower and redevelopment of the site after determining it would be more cost efficient to demolish the tower and put a new building in its place.
Closure and demolition
In 2016, the building was abandoned and closed due to the structural condition of the building; the final tenants moved out by October 2016. In July 2016, the building went up for sale. Falling concrete and water leaks from the building were reported in its later years, and after two years of debate as to whether to restore or tear down the building, the decision was ultimately made to demolish the tower.
On March 11, 2018, the Capital Plaza Office Tower was demolished via implosion with 1,500 pounds of explosives by main contractor Renascent, Inc. and subcontractor Controlled Demolition, Inc. to make room for a new 5-story office building, park, and 1,100-space parking garage.
In 2019, the Mayo-Underwood Building, a new state building, opened in the same location, named after the former Mayo–Underwood School.
References
1972 establishments in Kentucky
2016 disestablishments in Kentucky
Buildings and structures in Frankfort, Kentucky
Buildings and structures demolished by controlled implosion
Demolished buildings and structures in Kentucky
Skyscraper office buildings in Kentucky
Government buildings completed in 1972
Buildings and structures demolished in 2018
Former skyscrapers | Capital Plaza Office Tower (Frankfort, Kentucky) | [
"Engineering"
] | 471 | [
"Buildings and structures demolished by controlled implosion",
"Architecture"
] |
78,325,161 | https://en.wikipedia.org/wiki/KM-391 | KM-391 is a serotonin reuptake inhibitor which was under development for the treatment of autism but was never marketed. It is taken by mouth.
Description
The drug showed activity in an animal model of autism. In this model, the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) is injected into the forebrain of newborn rat pups and this results in neonatal serotonin depletion, development of autism-like behaviors, and reduced neuroplasticity. KM-391 was able to restore brain serotonin concentrations to near-normal levels, restore normal behaviors, and increase neuroplasticity. Moreover, it was more efficacious than fluoxetine in this model. KM-391 also diminished the intensification of autism-like behaviors, such as repetitive behaviors and sensitivity to touch, that occurred when an oxytocin receptor antagonist was added in the model.
KM-391 was under development by Cellceutix Corporation (now Innovation Pharmaceuticals). It remained under development as late as 2012 and reached the preclinical research stage of development for autism. However, its development was eventually suspended.
See also
Zolmitriptan § Social deficits and aggression
References
Abandoned drugs
Drugs with undisclosed chemical structures
Serotonin reuptake inhibitors
Treatment of autism | KM-391 | [
"Chemistry"
] | 289 | [
"Drug safety",
"Abandoned drugs"
] |
78,325,418 | https://en.wikipedia.org/wiki/PKS%201622-297 | PKS 1622-297 is a blazar located in the constellation of Scorpius. It is one of the brightest objects of its type in the gamma ray region. It has a redshift of (z) 0.815. This blazar was first discovered as a compact astronomical radio source in 1970 by astronomers who were conducting interferometer observations and identified with an optical counterpart in 1984. In addition, the radio spectrum of the source appears flat, making it a flat-spectrum radio quasar (FRSQ).
Description
PKS 1622-297 produced a powerful gamma ray outburst in June and July 1995. This was detected by Energetic Gamma Ray Experiment Telescope (EGRET) in the year 1995, where its outburst in the energy range above 100 MeV lasted for a period of five weeks. However no presence of MeV emission was detected. A major flare in PKS 1622-297 was observed by EGRET, and lasted around two days. Subsequent optical observations in 1996 and 1997 as well as three nights in 2001, showed the source is much fainter. Two other flares were detected in March 2010 and July 2014.
A three-week radio, optical and X-ray campaign was conducted on PKS 1622–297 by the Rossi X-ray Timing Explorer as well as the University of Michigan Radio Astronomy Observatory and optical telescopes at Cerro Tololo Inter-American Observatory in Chile. Results indicated the object was a weak X-ray emitter and was also redder during its bright optical flux state.
Radio images made of the object via Very Long Baseline Interferometry observations showed the source having an elongated structure towards the west on parsec scales. Three components are found in a form of a bright core and two weak jet components showing superluminal motion reaching up to 12.1 h−1 c. There is a jet along the position angle of 69°, made up of a prominent component 15 mas from the core with a diffused structure extending out to 30 mas. However a VLBI Space Observatory Programme (VSOP) image shows it having a weak component and a strong core. In an Australia Telescope Compact Array (ATCA) imaging at 4.8 GHz, the source has a bright core with strong extended emission in form of two components. These components are placed in equal angular distances on sides of the core and of similar brightness and sizes.
The supermassive black hole in PKS 1622-297 is estimated to be 8 x 108 Mʘ with the limit of the Schwarzschild radius being Rg > 2.5 x 1014 centimeters.
References
External links
PKS 1622-297 on SIMBAD
PKS 1622-297 on NASA/IPAC Database
Blazars
Quasars
Scorpius
Active galaxies
2828823
Astronomical objects discovered in 1970 | PKS 1622-297 | [
"Astronomy"
] | 573 | [
"Scorpius",
"Constellations"
] |
78,325,805 | https://en.wikipedia.org/wiki/Obecabtagene%20autoleucel | Obecabtagene autoleucel, sold under the brand name Aucatzyl, is an anti-cancer medication used for the treatment of acute lymphoblastic leukemia. It is a CD19-directed genetically modified autologous T-cell immunotherapy.
The most common side effects include cytokine release syndrome, infections-pathogen unspecified, musculoskeletal pain, viral infections, fever, nausea, bacterial infectious disorders, diarrhea, febrile neutropenia, immune effector cell-associated neurotoxicity syndrome, hypotension, pain, fatigue, headache, encephalopathy, and hemorrhage.
Obecabtagene autoleucel was approved for medical use in the United States in November 2024.
Medical uses
Obecabtagene autoleucel is indicated for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia.
Side effects
The US Food and Drug Administration (FDA) approved prescribing information for obecabtagene autoleucel has a boxed warning for cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and T-cell malignancies.
The most common side effects include cytokine release syndrome, infections-pathogen unspecified, musculoskeletal pain, viral infections, fever, nausea, bacterial infectious disorders, diarrhea, febrile neutropenia, immune effector cell-associated neurotoxicity syndrome, hypotension, pain, fatigue, headache, encephalopathy, and hemorrhage.
History
Efficacy was evaluated in FELIX (NCT04404660), an open-label, multicenter, single-arm trial that enrolled adults with relapsed or refractory CD19-positive B-cell acute lymphoblastic leukemia. Enrolled participants were required to have relapsed following a remission lasting twelve months or less, relapsed or refractory acute lymphoblastic leukemia following two or more prior lines of systemic therapy, or disease that was relapsed or refractory three or more months after allogeneic stem cell transplantation.
The major efficacy outcome measures were rate and duration of complete remission achieved within three months after infusion. Additional outcome measures were rate and duration of overall complete remission which includes complete remission and complete remission with incomplete hematologic recovery, at any time. Of the 65 participants evaluable for efficacy, 27 participants (42%; 95% confidence interval [CI]: 29%, 54%) achieved complete remission within three months. The median duration of complete remission achieved within three months was 14.1 months (95% CI: 6.1, not reached).
The US Food and Drug Administration (FDA) granted the application for obecabtagene autoleucel regenerative medicine advanced therapy (RMAT) and orphan drug designations.
Society and culture
Legal status
Obecabtagene autoleucel was approved for medical use in the United States in November 2024.
Names
Obecabtagene autoleucel is the international nonproprietary name.
It is sold under the brand name Aucatzyl.
References
External links
Antineoplastic drugs
Approved gene therapies
CAR T-cell therapy
Drugs that are a gene therapy
Orphan drugs | Obecabtagene autoleucel | [
"Chemistry",
"Biology"
] | 723 | [
"Pharmacology",
"CAR T-cell therapy",
"Medicinal chemistry stubs",
"Cell therapies",
"Pharmacology stubs"
] |
78,326,431 | https://en.wikipedia.org/wiki/The%20Measure%20of%20Reality | The Measure of Reality: Quantification in Western Europe, 1250-1600 is a 1997 nonfiction historiography and macrohistory book by Alfred W. Crosby, about the role of quantification in Western civilization. It is published by Cambridge University Press.
Content
The Measure of Reality examines the origins and effects of quantitative thinking in post-medieval European history', suggesting it as a major factor in the ensuing European colonial domination of much of the rest of the world. For Crosby, this was made possible by a shift in mindset and worldview that the author collectively calls ( Bourdieu's comes to mind) toward quantitative and visual thinking fostering a superior understanding of science and technology.
To illustrate how Crosby describes the shift away from a qualitative and theological view of reality, philosopher Denis Dutton offers the example of geography:
For James D. Parr Crosby
The book is divided into three sections, where the first introduces a new view of time and space as a continuum that could be subdivided and segmented, assisted by the application of the Hindu–Arabic numeral system. The second part follows the evolution of quantification in music, painting, and bookkeeping. The third part presents the maturation of what Crosby describes as the new model of European reality, established on visualization and quantification as well as a linear and analytical but unbounded view of history driven by "progress", versus what he terms the venerable model, a more qualitative, experiential, and boundedly cyclical worldview inherited from classical antiquity.
Crosby adopts the metaphor of the striking match to illustrate how this revolution took place, with the influx of the
Aristotelian corpus into the Latin West. This took place via the Arab world starting in the thirteen century, and provided the "oxygen and combustibles" that were then "made into fire" by composers, painters, and bookkeepers in what Crosby describes as a "shift to the visual" taken by composers, painters, and bookkeepers.
The ingredients of this revolution in visualization and quantification were, in Crosby's analysis, the birth of polyphonic music at the cathedral of Notre Dame in Paris, the development of perspective in the paintings of the Italian Renaissance, and the adoption of double-entry bookkeeping among 14th-century Italian accountants.
Reception
The Measure of Reality was praised, in the journal Historia Mathematica by mathematician Frank Swetz, as "a pleasant and informative book" surveying some of the trends of quantification in European society during the period; and, by both Swetz and (in Magill's Book Reviews) by Barbara Hauser, for the breadth of the author's scholarship.' Swetz was in some measure critical, especially of the lack of depth and detail on pre-modern measurement systems; and of Crosby not very deeply exploring the idea of modern European worldview being shaped by measurement.
Hauser noted especially the book's recurrent theme in Crosby's work of conflict between the religious and sacred (more in Europe's past) and the secular (more in its future). Her summary of the book's theme:
For this reviewer Crosby discounts what previous societies achieved by way of mathematics, geometry, and measuring space, time and weights, from the introduction of the zero (Indian) to subdivision in 360 degrees and 60-minute hours
( Babylonian), the Greek Pythagorean theorem, the Julian calendar (Roman) all the way to the ancient Athenian Tholos (a bureau for the registering of weights and scales).
For John D. Wilson in Magill's Literary Annual, while the thesis upheld by Crosby was in need of a full demonstration (probably by later writers), the book was nevertheless "enjoyable and highly stimulating ... full of curious lore that encourages readers to look more closely at the habits of thought on which their way of life is built." However, Wilson (like Swetz) felt that Crosby did not really systematically argue his premise, but rather devoted most of the work to exploring examples of quantitative and visual developments without explaining their centrality to a putative new European world-view. Wilson also disputed some of Crosby's specific claims, such as that rhythmic complexity in music requires late-Western-style time quantification and notation.
While criticizing Crosby’s hasty connection between quanta and imperialism, historian of science Steven Shapin notes:
In a 2001 literature review of then-recent macrohistory works, in The American Historical Review historian Gale Stokes examines The Measure of Reality along with thematically similar works, including Guns, Germs, and Steel (1997) by Jared Diamond, The Wealth and Poverty of Nations (1998) by David Landes, ReOrient (1998) by Andre Gunder Frank, and The Great Divergence (2000) by Kenneth Pomeranz, among others. Another book to which Crosy’s is compared is Michael Adas' work Machines as a Measure of Man on the role of technology in European imperialism – the difference being that Adas’ machine and technologies are, in Crosby’s reading, all descending from the quantifying spirit of the age. While conceding that scholars are split when it comes to the methodological value of macrohistorical approaches at all, he divides these works into two general schools of thought on the rise of Europe since the Renaissance: that there was something intrinsically or situationally special about European society, versus that Europe simply "lucked into" a period of dominance through resource acquisition and exploitation at a greater rate than in Asia. Stokes classified Crosby in the first camp, and pointed out that anthropologist Jack Goody, in East in the West (1996) has held that quantification technologies were not uniquely European, but developments from China through India to the Mediterranean since the Bronze Age. Crosby's model stands out in holding European quantification to have become a progressively accelerating cultural habit.
See also
Sociology of quantification
References
External links
The Measure of Reality page at Cambridge University Press
Historiography
Quantification (science)
Science and technology studies
1997 non-fiction books
Cambridge University Press books | The Measure of Reality | [
"Mathematics",
"Technology"
] | 1,255 | [
"Quantity",
"Science and technology studies",
"Quantification (science)"
] |
78,326,909 | https://en.wikipedia.org/wiki/Africa%20Prize%20For%20Engineering%20Innovation | The Africa Prize For Engineering Innovation is an award for excellence in engineering in Sub-Saharan Africa. Eight months are set aside to help the contestants. The winner is awarded £25,000, with the second, third and fourth runners-up gaining £10,000 each.
History
The award was introduced in January 2014 by the Royal Academy of Engineering in the United Kingdom. Competitor engineers must be from Sub-Saharan Africa.
In 2024 Esther Kimani was the winner of the prize and, because it was the award's tenth year, she was awarded £50,000. She was second winner from Kenya. Kimani had developed a method of identifying diseases in crops using image analysis.
Benefits
Sixteen competitors are selected and they are given any support they need during the competition and beyond to deliver their projects. These competitors receive training and support and they get the opportunity to improve their networking. The winner receives £25,000 and the second, third and fourth places are awarded £10,000.
Award recipients
2015 Dr. Askwar Hilonga and team of Tanzania
2016 Arthur Zang of Cameroon
2017 Godwin Benson of Nigeria
2018 Brian Gitta and his team from Uganda
2019 Neo Hutiri from South Africa
2020 Charlette N'Guessan from Ghana
2021 Noël N'guessan from Ivory Coast
2022 Norah Magero from Kenya
2023 Anatoli Kirigwajjo from Uganda
2023 Edmund Wessels from South Africa
2024 Esther Kimani, Kenya
References
International awards
Awards established in 2014
Awards of the Royal Academy of Engineering
2014 establishments in the United Kingdom | Africa Prize For Engineering Innovation | [
"Technology"
] | 316 | [
"Science and technology awards",
"International science and technology awards"
] |
78,328,530 | https://en.wikipedia.org/wiki/Thomas%20Carr%20%28engineer%29 | Thomas Carr (1824–1874) was an English mechanical engineer of Montpelier, Bristol. Of his several inventions, the Carr's disintegrator was the best-known of its type.
Early life and education
Thomas Carr was born at Durham, England, on 23 January 1824. He was the third son of Rev. John Carr, professor of mathematics in the University of Durham.
Carr showed a talent for mechanics while still a child. At the age of 15, he was placed with Messrs. Bury Curtis and Kennedy of Liverpool. He remained three years, distinguishing himself through the accuracy of his drawings.
Career
Carr invented an improved steering apparatus for ships; Though is received a high approval by authorities on the subject, it was not generally adopted owing to the expense required in repairing it. Some time afterwards, he brought out a new method of drying glue, which could be used at any time -a matter of great importance in the manufacturer of this article- and it was sold to a manufacturer in Leeds. He also originated several other inventions.
His last and principal invention was the disintegrator. This machine, which he described to the Institution of Mechanical Engineers, was extensively used in various trades and manufactures especially in connection with agriculture. It was considered to be one of the most valuable inventions of its era. He also brought out a flour mill on the disintegrator principle, which was used extensively in Scotland.
Carr became a member of the Institution of Mechanical Engineers in 1872.
Death
Carr died in Bristol, England on 29 March 1874, at the age of 50.
References
External links
Thomas Carr at Grace's Guide to British Industrial History
1824 births
1874 deaths
English mechanical engineers
English inventors
People from Durham, England
Institution of Mechanical Engineers | Thomas Carr (engineer) | [
"Engineering"
] | 356 | [
"Institution of Mechanical Engineers",
"Mechanical engineering organizations"
] |
78,328,970 | https://en.wikipedia.org/wiki/Qing-Yun%20Chen | Qing-Yun Chen (; 25 January 1929 – 2 March 2023) was a Chinese organic chemist and member of the Chinese Academy of Sciences, specializing in the field of organic fluorine chemistry.
Biography
Chen was born on January 25, 1929, in Yuanjiang, Hunan Province, into a family that was not particularly wealthy. His parents attached great importance to education and did their best to ensure that he received a formal education; in 1948, Chen was admitted to Peking University, from which he graduated four years later with a degree in chemistry.
After finishing his bachelor's degree in 1952, he joined the Instrumentation Hall of the Chinese Academy of Sciences (now known as Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences) as a research assistant. In 1956, after passing the USSR entrance exam, he entered the Institute of Elemental Organic Compounds of the Academy of Sciences of the Soviet Union to obtain his master's degree. He received his Ph.D. in organofluorine chemistry in 1960 under the supervision of Ivan Knunyants and N. P. Gambaryan.
In 1960, after finishing his degree, he returned to China to study the development of fluorinated rubber, and in 1963, he was transferred to the Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences, where he continued the development of fluorinated rubber. Chen and colleagues found the chromate fog inhibitor F-53 and studied and synthesized a variety of chemicals. He then used this as a basis for a systematic study of single-electron transfer of fluoroalkyl halides. In 1993, he was elected as an academician of the Chinese Academy of Sciences. After 2000, Chen expanded his research interests to the synthesis and application of fluoroalkylated porphyrins. He developed two practical methods for the preparation of various fluoroalkylated porphyrins, the sulfinatodehalogenation reaction and the palladium-catalyzed cross-coupling reaction.
On March 2, 2023, he died at the age of 94 in Shanghai.
Personal life
In 1961, Chen married Zhi-Fen Yu and they had a son and a daughter.
References
1929 births
2023 deaths
Chemists from Hunan
Chinese organic chemists
Members of the Chinese Academy of Sciences
Peking University alumni | Qing-Yun Chen | [
"Chemistry"
] | 476 | [
"Organic chemists",
"Chinese organic chemists"
] |
78,329,089 | https://en.wikipedia.org/wiki/Casanova%27s%20Lottery | Casanova's Lottery: The History of a Revolutionary Game of Chance is a history book about the French Loterie by historian and statistician Stephen M. Stigler.
Content
Stigler's Casanova’s Lottery: The History of a Revolutionary Game of Chance tells how, thanks to the direct involvement of the Venetian Giacomo Casanova, the French Loterie was established, lasting from 1758 to 1836 – with a four-year interruption during the French Revolution in 1793–1797.
A quarter of a billion tickets were sold over that period through lottery offices all over France, thanks to which the state budget received "millions of livres (and then francs)".
The Loterie was unique because, unlike a raffle, the maximum possible winning to be disbursed by the state to the winners was not known in advance. Thus, it was considerably riskier for the French administration, be it monarchical, republican, or imperial.
Bets were made on the drawing without replacement of five random numbers out of a total of 90 numbers, each number being associated with a woman's name to make fraud more difficult. Bettors wagered on one, two or three (and later four) numbers.
The book describes the various stages of the Loterie. Initially established to fund the French École militaire – the discussions leading to the establishment of the school saw the direct involvement of the creator of the École militaire, Joseph Pâris Duverney, as well as of the French academician Jean d'Alembert, of Madame Pompadour and of Casanova – the lottery was subsequently conducted under the responsibility of the ministry of finance.
Among the interesting stories told in the volume is how Voltaire won a fortune of several million francs by participating to a scheme in an earlier French state lottery that aimed at reimbursing state debtors.
The interest of the book also comes from the author's statistical expertise. Stigler relies on Menut de Saint Mesmin's Almanach Romain sur la loterie de France, published in 1834, and intended as a guide for bettors. Since the Almanach reports the winning numbers drawn since 1758 as well as the prizes paid out, it constitutes for Stigler
Two appendices describe respectively the formulae for the calculus of probabilities relative to the lottery and a theorem from Pierre-Simon Laplace on the distribution of the number of draws needed for all 90 numbers to appear at least once.
The book won the 2023 Neumann_Prize of the British Society for the History of Mathematics.
See also
Lottery
Raffle
Game of chance
References
External links
Casanova's Lottery page at Chicago University Press
Statistics
Probability
Science and technology studies
2022 non-fiction books | Casanova's Lottery | [
"Physics",
"Mathematics",
"Technology"
] | 557 | [
"Physical quantities",
"Statistics",
"Science and technology studies",
"Probability and statistics",
"Wikipedia categories named after physical quantities",
"Probability"
] |
78,330,672 | https://en.wikipedia.org/wiki/VU0530244 | VU0530244 is a potent, selective, and putatively peripherally restricted serotonin 5-HT2B receptor antagonist which was first described in 2023. Another similar drug, VU0631019, was also described alongside VU0530244. They were identified via high-throughput screening (HTS).
The affinity () of VU0530244 for the serotonin 5-HT2B receptor was found to be 17.3nM. Its affinity () values at the serotonin 5-HT2A and 5-HT2C receptors were greater than 10,000nM (>578-fold less than for the serotonin 5-HT2B receptor). The drug is predicted to be a robust P-glycoprotein substrate and hence is expected to have very limited blood–brain barrier permeability.
Serotonin 5-HT2B receptor antagonists are of interest for potential use in medicine to treat pulmonary arterial hypertension, valvular heart disease, and related cardiopathies. However, reduced serotonin 5-HT2B receptor signaling in the central nervous system has been linked to adverse effects such as impulsivity, suicidality, and sleep disturbances, among others. Such potential side effects can be avoided with the use of peripherally restricted serotonin 5-HT2B receptor antagonists.
In addition, activation of serotonin 5-HT2B receptors is thought to be responsible for development of cardiac fibrosis and valvulopathy as well as pulmonary hypertension with certain serotonergic agents, including direct serotonin 5-HT2B receptor agonists like cabergoline, ergotamine, methysergide, and pergolide, serotonin releasing agents like chlorphentermine and aminorex, and dual serotonin 5-HT2B receptor agonists and serotonin releasing agents like fenfluramine, dexfenfluramine, benfluorex, and MDMA. Serotonergic psychedelics like lysergic acid diethylamide (LSD) and psilocybin as well as entactogens like MDMA are also potent serotonin 5-HT2B receptor agonists, and there have been concerns about chronic administration of these and related agents in medical contexts due to possible development of cardiac and other complications. Selective serotonin 5-HT2B receptor antagonism has been found to fully prevent the cardiotoxicity of dexnorfenfluramine in rodents.
In 2024, the paper that described the discovery of the VU0530244 won the 2023 Rosalind Franklin Society Special Award in Science for contributions to the journal Assay and Drug Development Technologies.
See also
BW-501C67
Xylamidine
References
4-Fluorophenyl compounds
5-HT2B antagonists
Azetidines
Benzimidazoles
Experimental drugs
Ketones
Peripherally selective drugs
Pyrazoles | VU0530244 | [
"Chemistry"
] | 653 | [
"Ketones",
"Functional groups"
] |
78,331,221 | https://en.wikipedia.org/wiki/Cold%20Regions%20Hydrological%20Modelling%20platform | The Cold Regions Hydrological Modelling (CRHM) Platform is a hydrological modelling program incorporating the seminal works of Don Gray, Raoul Granger, Pat Landine, and John Pomeroy, among others, in representing hydrological processes for small to mid-sized catchments in cold regions of the earth. Code and software development was carried out by University of Saskatchewan engineer, Tom Brown. Used extensively and supported by the University of Saskatchewan's Centre for Hydrology, CRHM has also been used in 57 Canadian and 31 organizations worldwide to build basin hydrology models. In Canada, the platform has been used to support hydrological predictions related to glacier and snow melt in the Canadian Rocky Mountains and western provinces. CRHM includes following components: Basin, Observation, Snow Transport, Interception, Radiation, Evaporation, Snowmelt, Infiltration, Soil Moisture Balance, Wetlands, Flow, Gravitational Snow Transport, Glacier Melt, and Freezing and Thawing Fronts Dynamics.
Operation
CRHM requires files (extension .obs) of high-frequency (preferably hourly) continuous time series of observed air temperature, wind speed, humidity, and precipitation. The R package CRHMr can be used to prepare these time series, including infilling missing values. CRHMr can also be used to post-process and plot CRHM outputs.
Other packages that can be used to acquire data for use by CRHM include MSCr which uses data from Meteorological Service of Canada files, Reanalysis, which creates .obs files from several types of reanalysis files, including ERA, WATCH and NARR, and WISKIr, which uses data from a Wiski web server.
Research supported by CRHM
CRHM has been used extensively in snow modelling and studies of the effects of climate change on cold regions headwater basins. Results from use of the model have also been used in studies of agricultural practices, changes in glaciers, grasslands, and boreal forests.
References
External links
Hydrology models | Cold Regions Hydrological Modelling platform | [
"Biology",
"Environmental_science"
] | 399 | [
"Hydrology",
"Environmental modelling",
"Hydrology models",
"Biological models"
] |
78,331,537 | https://en.wikipedia.org/wiki/Global%20Water%20Futures%20Program | Global Water Futures is a networked Canadian scientific research program, supported in large part by the Canada First Research Excellence Fund. The program's design and foundational data management were informed by several predecessor Canadian research programs including the Mackenzie GEWEX study (MAGS) and the Changing Cold Regions Network and were influenced by increasing awareness of climate change and development threats to Canadian water supplies and quality.
The program, designed to improve disaster warning, to predict water quantity and quality, and to develop risk management tools for water planners and managers, was set up in 2016 at the University of Saskatchewan Global Institute for Water Security with three main university partners: the University of Waterloo, Wilfrid Laurier University, and McMaster University.
Program activities were clustered under three categories:
identifying and predicting change in cold regions,
developing big data and decision support systems, and
designing user solutions.
The program's geographic coverage includes important river basins and ecological, climatological, and physiographic regions. Under the Global Institute for Water Security, Global Water Futures committed to supporting the United Nations Sustainable Development Goals. The program was intended to run for seven years: interruptions caused by the COVID-19 pandemic allowed for some extensions until 2024.
Budget
The budget of CAD 77.84 million from the Canada First Research Excellence Fund, was supplemented by CAD 223.15 million in cash and in-kind contributions, including historical data sets from collaborating research institutions, and other federal government funding. Approximate budget allocations for each of the program categories were:
identifying and predicting change in cold regions: 40%
developing big data and decision support systems: 45%
designing user solutions: 15%.
The program set out to facilitate co-production of knowledge with practitioners and other knowledge users, and to apply transdisciplinary approaches. In January 2019, recognizing the significant role that water plays in Canadian Indigenous culture and communities, the program announced funding for six Indigenous co-led projects to focus on water-related issues. Complementary to these projects was organization of a meeting in 2023 at Mistawasis Nêhiyawak, Saskatchewan of Indigenous representatives from across Canada who developed a statement and protocol that called for better co-production of water knowledge.
Outcomes
The program developed 64 projects and core teams, supported operation of 76 scientific observatories and research stations, and has trained 552 student researchers. These involved collaboration with international partners, especially in mountain hydrology. The program's work in computational hydrology is especially recognized for its work on models that are applicable internationally. Standards for data management and a common catalogue were developed to preserve access to datasets produced by individual projects.
Global Water Futures has also helped to inform development of the Canada Water Agency, a new federal institution intended to address fragmentation of water management in Canada.
Outputs from Global Water Futures findings include peer-reviewed journal articles, conference papers, datasets, and predictive models and tools related to climate that are being applied both within and outside of Canada. Six annual open science meetings allowed dissemination and discussion of the program work with academic researchers and practitioners. A special project partnered scientists with artists to create paintings and other art that reflected the themes of the Global Water Futures program.
Also of note was adaptation in 2020 of the project, Next generation solutions to ensure healthy water resources for future generations, to provide Covid-19 wastewater surveillance results to major Saskatchewan urban centres, work that continued into 2023.
Global Water Futures Observatories
In 2023, through the Canada Foundation for Innovation (CFI) Major Science Initiatives (MSI) program, the Government of Canada approved funding support for Global Water Futures Observatories to maintain until 2029 the observatories, research facilities, and data management systems developed and supported by the program.
See also
List of rivers of Canada
List of lakes of Canada
References
External links
"Water Futures for the World We Want"
Cryosphere
Science and technology in Canada | Global Water Futures Program | [
"Environmental_science"
] | 794 | [
"Cryosphere",
"Hydrology"
] |
78,333,232 | https://en.wikipedia.org/wiki/Revumenib | Revumenib, sold under the brand name Revuforj, is an anti-cancer medication used for the treatment of acute leukemias harboring lysine methyltransferase 2A gene (KMT2A) rearrangements. It is designed to disrupt the interaction between menin and KMT2A (also known as MLL), which plays a role in the pathogenesis of these leukemias. It is taken by mouth.
The most common adverse reactions include hemorrhage, nausea, increased phosphate, musculoskeletal pain, infection, increased aspartate aminotransferase, febrile neutropenia, increased alanine aminotransferase, increased intact parathyroid hormone, bacterial infection, diarrhea, differentiation syndrome, electrocardiogram QT prolonged, decreased phosphate, increased triglycerides, decreased potassium, decreased appetite, constipation, edema, viral infection, fatigue, and increased alkaline phosphatase.
Revumenib was approved for medical use in the United States in November 2024. The US Food and Drug Administration (FDA) considers it to be a first-in-class medication.
Medical uses
Revumenib is indicated for the treatment of relapsed or refractory acute leukemia with a lysine methyltransferase 2A gene (KMT2A) translocation.
History
Efficacy was evaluated in a single-arm cohort of an open-label, multicenter trial (SNDX-5613-0700, NCT04065399; AUGMENT-101) in 104 adult and pediatric participants (at least 30 days old) with relapsed or refractory (R/R) acute leukemia with a lysine methyltransferase 2A gene translocation. Participants with an 11q23 partial tandem duplication were excluded. Revumenib was administered until disease progression, unacceptable toxicity, failure to achieve morphological leukemia-free state by four cycles of treatment, or hematopoietic stem cell transplantation.
The US Food and Drug Administration (FDA) granted the application for revumenib priority review, breakthrough therapy, and orphan drug designations.
Society and culture
Legal status
Revumenib was approved for medical use in the United States in November 2024.
Names
Revumenib is the international nonproprietary name.
It is sold under the brand name Revuforj.
References
Further reading
External links
Azetidines
Benzamides
Cyclohexanes
Diaryl ethers
Fluorobenzene derivatives
Orphan drugs
Piperidines
Pyrimidines
Spiro compounds
Sulfonamides
Isopropylamino compounds | Revumenib | [
"Chemistry"
] | 558 | [
"Organic compounds",
"Spiro compounds"
] |
78,333,617 | https://en.wikipedia.org/wiki/Cuo%20%28unit%29 | A Cuo () in China or sai in Japan is a unit of volume measurement.
One cuo equals 1⁄1000 sheng.
It is 1 mL (millilitres) in China and 1.804 mL in Japan.
The word cuo () means (a) to pick up (e.g., salt) using one's fingertips, or (b) the small amount of something that can be picked up in this way.
China
Japan
Volume
For more details, please see Sheng (volume)
See also
Chinese units of measurement
Japanese units of measurement
:zh:中國度量衡
References
Units of volume
Customary units of measurement | Cuo (unit) | [
"Mathematics"
] | 135 | [
"Units of volume",
"Quantity",
"Customary units of measurement",
"Units of measurement"
] |
78,335,790 | https://en.wikipedia.org/wiki/Proceedings%20of%20Higher%20Education%20Institutions.%20Textile%20Industry%20Technology | The Proceedings of Higher Education Institutions. Textile Industry Technology (Russian: Известия высших учебных заведений. Технология текстильной промышленности) is a bimonthly peer-reviewed scientific journal covering research on textile and light industry technology. It was established in 1957 and publishes studies on innovations in textile production processes, the development of new materials, ecological and energy-saving technologies, and engineering applications in textile manufacturing.
Abstracting and indexing
The journal is abstracted and indexed in the Russian Science Citation Index, Scopus, and Chemical Abstracts Service.
References
External links
Multilingual journals
Textile journals
Academic journals established in 1957 | Proceedings of Higher Education Institutions. Textile Industry Technology | [
"Materials_science"
] | 174 | [
"Materials science journals",
"Textile journals"
] |
78,336,462 | https://en.wikipedia.org/wiki/ExxonMobil%20Beaumont%20Refinery | The ExxonMobil Refinery in Beaumont, Texas was built along the banks of the Neches River in 1903. The refinery is currently one of the largest in the world with a nameplate capacity of 634,000 bpd. The plant is also highly integrated with petrochemicals production and lubricants and is a critical part of the Texas-Louisiana gulf coast energy infrastructure. The site encompasses more than 2,700 acres and is staffed by 2,000 employees daily plus another 3,000 contractors to support maintenance and construction activities.
History
In 1903, construction started on the Burt Refining Company to capitalize on the prolific Spindletop field located just south of Beaumont. Little was known of Burt Refining's origins other than George A. Burts was the owner and was rumored to have been an agent of John D. Rockefeller. In 1909, the State of Texas seized the refinery as an illegal affiliate of Standard Oil and sold in an auction to Magnolia Petroleum Co. The refinery became Texas's third largest by 1920 under Magnolia as the company expanded throughout the region. As Magnolia Petroleum Company expanded its influence in the southwestern United States, Standard Oil Company of New York (SOCONY Mobil) began acquiring shares in the company. In December 1925, all Magnolia stock was exchanged for Standard Oil of New York shares, and the Texas assets were subsequently transferred to Magnolia Petroleum Company. The Magnolia Refinery played a key role during World War II as it stepped up production and shipped oil globally. By 1959, the operations of the Magnolia Oil Company had been merged entirely into SOCONY Mobil. The refinery further in the ensuing decades to becomes Beaumont's largest employer and eventually Mobil's largest refinery by 1980. In 1999, Exxon and Mobil merged to form the largest oil company in the world and the Beaumont Refinery became one of the 5 largest refineries in the combined company's portfolio. Following a $2 billion major capital investment program twenty five years later, including a new 250,000 bpd crude unit, Beaumont became the third largest oil refinery in North America and the largest of any of ExxonMobil's plants.
Units
Petroleum refining units
According to ExxonMobil's filings with the US DOE's Energy Information Agency, the unit capacities for the Beaumont Refinery are presented below:
The refinery has a Nelson complexity index of 9.0, making it moderately complex.
The refinery has three crude trains. The smallest is CDU A110,000 bpd. The second crude unit is CDU B 274,000 bpd. The newest CDU C was designed for lighter crude oils produced by shale crudes and light tight oils and is of 250,000 bpd of capacity.
Starting in 2019, the refinery underwent a major expansion with a 65% increase in its nameplate capacity as part of a $2 billion program. KBR was contracted to lead the work with a scope that covered offsite facilities and interconnecting units within the expansion This followed ExxonMobil's earlier contract with TechnipFMC PLC for EPC services on four new units, including an atmospheric pipe still, hydrotreater units, and a benzene recovery system.
The refinery has a large lubricants plant located on 27 acres within the refinery. The lubes plant produces 160 million gallons of lubricants across 275 product types and employs 175 employees and 163 contractors.
Electricity generation
The refinery has three power plants that are integrated to provide steam and thermal heating to the refinery, in addition to selling electricity to the grid. These are:
Petrochemical units
The refinery is also integrated with a large ExxonMobil petrochemical facility that is collocated on the same plot. Total ethylene cracking capacity for the site is currently 816,000 tons per year according to the Oil & Gas Journal Survey of Steam Crackers.
Greenhouse gas emissions history
As a major emitting facility, the ExxonMobil Beaumont Refinery and Petrochemical Site must report its complete greenhouse gas emissions to the EPA every year subject to the EPA's Greenhouse Gas Reporting Program. The Baytown site's Refinery Facility ID is 110041990913 and the Chemical Plant's is 110000464131.
Statutory reporting data is in the table below:
Labor relations
The refinery is represented by USW Local 13-243. Labor relations have been contentious at times The U.S. National Labor Relations Board (NLRB) determined that ExxonMobil's 10-month lockout of over 600 workers at the refinery and lube plant was an unlawful attempt to remove the United Steelworkers union as the workers' representative. The NLRB asked an administrative law judge to issue remedies, including back pay, potentially costing Exxon tens of millions. The lockout, which lasted from May 2021 to March 2022, continued while replacements were hired. The NLRB found that Exxon's actions, including messages to workers offering job reinstatement if they voted to decertify the union, undermined federal employee rights. Despite the company's efforts, workers voted to retain USW local 13–243 as their representative.
Operating history and accidents
On April 17, 2013, an explosion and fire at ExxonMobil's Beaumont, Texas refinery injured at least 12 people and killed two. The incident was caused by a hydrotreater heat exchanger, releasing hydrocarbons that ignited. Following the event, multiple negligence-based personal injury lawsuits were filed. ExxonMobil attributed the fire to the actions of Clean Harbors, a subcontractor responsible for cleaning operations. ExxonMobil was fined $616,000 by the U.S. Department of Justice and the Environmental Protection Agency for the fire. After a trial, a jury awarded damages to the families of the workers who died of $44 million.
In 2016, a 37-year old contract worker named Migual Barron was killed during a turnaround at the refinery when struck by a heat exchanger on the 110,000 bpd crude unit.
In 2017, a female contractor named Yesenia Espinoza was killed on while working on the same crude unit when a pipe fell and landed on her. After the accident, a judge issued a temporary restraining order to cease work on the crude unit until an investigation could be completed. The family of Espinoza sued ExxonMobil for medical, burial, funeral expenses plus damages.
See also
Atmospheric Distillation
Alkylation
Cracking
Delayed Coking
Hydrotreating
References
Oil refineries in Texas
ExxonMobil buildings and structures
Energy infrastructure completed in 1903
1903 establishments in Texas
Oil refineries in the United States
Energy infrastructure
Crude oil pipelines in the United States
Electric power
Petrochemical companies
Petrochemical industry
Beaumont, Texas | ExxonMobil Beaumont Refinery | [
"Physics",
"Chemistry",
"Engineering"
] | 1,377 | [
"Physical quantities",
"Power (physics)",
"Electric power",
"Electrical engineering",
"Petrochemical industry"
] |
78,336,912 | https://en.wikipedia.org/wiki/Darovasertib | Darovasertib is an investigational new drug that is being evaluated for the treatment of metastatic uveal melanoma and other cancers. It is a first-in-class oral, small molecule inhibitor of protein kinase C (PKC).
It selectively targets mutant forms of PKC found in tumors with GNAQ or GNA11 mutations, which are present in approximately 90% of uveal melanoma cases. The U.S. Food and Drug Administration (FDA) granted orphan drug designation to darovasertib for the treatment of uveal melanoma on May 2, 2022, highlighting its potential to address an unmet medical need in this rare and aggressive form of eye cancer. As of 2024, darovasertib is in clinical development, with ongoing phase 1/2 trials evaluating its efficacy both as a monotherapy and in combination with other agents, such as binimetinib and crizotinib.
References
Amides
Pyridines
Pyrazines
Trifluoromethyl compounds
Piperidines | Darovasertib | [
"Chemistry"
] | 222 | [
"Pharmacology",
"Functional groups",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Amides"
] |
78,337,880 | https://en.wikipedia.org/wiki/NGC%205162 | NGC5162 is a very large spiral galaxy in the constellation of Virgo. Its velocity with respect to the cosmic microwave background is 7125 ± 20km/s, which corresponds to a Hubble distance of . In addition, 11 non redshift measurements give a distance of . The galaxy was discovered by German-British astronomer William Herschel on 15 March 1784. It was also observed by Lewis Swift on 19 April 1887, resulting in the galaxy being included twice in the New General Catalogue, as both NGC 5162 and NGC 5174.
The SIMBAD database lists NGC5162 as a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms. NGC 5162 is a field galaxy, i.e. it does not belong to a larger galaxy group or cluster and hence is gravitationally alone.
Supernovae
Two supernovae have been observed in NGC 5162:
Kōichi Itagaki discovered SN2007cd (type unknown, mag. 17.5) on 27 April 2007.
The Xingming Observatory Sky Survey discovered SN2024aawh (typeII, mag. 18.11) on 10 November 2024.
See also
List of NGC objects (5001–6000)
References
External links
5162
047346
+02-34-018
08475
13269+1115
Virgo (constellation)
17840315
Discoveries by William Herschel
Spiral galaxies
Field galaxies
LINER galaxies | NGC 5162 | [
"Astronomy"
] | 312 | [
"Virgo (constellation)",
"Constellations"
] |
78,338,372 | https://en.wikipedia.org/wiki/Boris%20Bakra%C4%8D | Boris Bakrač (25 March 1912 in Požega – 29 November 1989 in Zagreb) was a Croatian civil engineer and politician. Bakrač graduated from the University of Zagreb in 1936 before starting a career in civil engineering. After the outbreak of the World War II and the Invasion of Yugoslavia, he joined the Communist Party of Yugoslavia, as its covert agent in Zagreb in 1942. A year later, the Partisan resistance command in Croatia appointed Bakrač the chief negotiator for prisoner exchanges with the Axis powers within the framework of the German–Yugoslav Partisan negotiations. He oversaw exchange of a total of 700 to 800 Axis-held prisoners of war in the process. He conducted the negotiations under the pseudonym Ivo Zuljević to conceal his identity.
In 1944, following the Belgrade offensive, Bakrač evacuated Mišo Broz, the youngest son of the Yugoslav Partisan leader Josip Broz Tito, from Zagreb to Belgrade. Mišo was born in Zagreb shortly after the outbreak of the war. He and his mother Herta Haas remained in the city and in the nearby area of Hrvatsko Zagorje aided by Partisan supporters.
After the war, Bakrač was the deputy minister and then minister of construction in the government of the People's Republic of Croatia between 1945 and 1951. From 1958 to 1963, Bakrač again became a member of the Croatian government. He was a member of the Croatian Sabor until 1974, serving as the deputy president of its Executive Committee from 1969 to 1972, and the deputy Speaker from 1972 to 1974. In 1975–1978, he was a member of the Presidnecy of Croatia tasked with international relations. Bakrač was also a member of the Assembly of Yugoslavia from 1953 to 1957, and a member of the Central Committee of the League of Communists of Croatia from 1954 to 1974.
At various times, Bakrač was the President of the Association of Engineers and Technicians of Croatia, the President of the Tourist Association of Croatia, the President of the Federal Chamber of Civil Engineers of Yugoslavia, the President of the Croatian Football Federation, the President of the Croatian Sports Association, and the President of the Yugoslav Olympic Committee. In 1960, he became a permanent member of the International Olympic Committee. In 1987, Bakrač received the Silver Olympic Order.
References
1912 births
1989 deaths
League of Communists of Croatia politicians
Croatian people of World War II
International Olympic Committee members
Recipients of the Olympic Order
Representatives in the modern Croatian Parliament
Members of the Assembly of the Socialist Federal Republic of Yugoslavia
Civil engineers
People from Požega, Croatia
University of Zagreb alumni | Boris Bakrač | [
"Engineering"
] | 523 | [
"Civil engineering",
"Civil engineers"
] |
78,339,675 | https://en.wikipedia.org/wiki/Shiquan%20River%20Sand%20Control%20Project | During the 1980s, ecological degradation and soil erosion resulted in severe sandstorms and the decline of the living conditions in Shiquanhe Town. To inhibit additional sand encroachment, the Ngari Prefecture formally initiated the Shiquan River Sand Control Project () in 1994.
Progress
Since the initiation of the sand control project, the Ngari Prefecture has consistently prioritized the Shiquanhe Town Basin biological sand control initiative as a crucial measure to advance ecological civilization, enhance and secure livelihoods. This endeavor has involved a cumulative investment of 150 million yuan, resulting in the afforestation of 22,754 acres, the planting of 4.5 million trees, and the cultivation of 6,100 acres of grass. The project has predominantly utilized local tree species such as Salix bangongensis and Tamarix ramosissima, supplemented by introduced species including Hippophae rhamnoides subsp. gyantsensis and Salix cheilophila, encompassing a total of seven tree species. The Ngari Prefecture allocates about 700,000 yuan annually for afforestation management in the town of Shiquanhe, ensuring a tree survival rate and afforestation preservation rate exceeding 80%.
The occurrence of wind and sand in Shiquanhe Town has been mitigated, the frost-free duration has grown from 83 days in 1994 to 170 days in 2017, and the annual average precipitation has risen from 76.5 millimeters in 1994 to 140 millimeters in 2017.
See also
Lhasa North and South Mountain Greening Project
Sengge Zangbo
References
Buildings and structures in Tibet
Environmental planning
Ecological processes | Shiquan River Sand Control Project | [
"Physics"
] | 336 | [
"Physical phenomena",
"Ecological processes",
"Earth phenomena"
] |
68,189,121 | https://en.wikipedia.org/wiki/Spherical%20conic | In mathematics, a spherical conic or sphero-conic is a curve on the sphere, the intersection of the sphere with a concentric elliptic cone. It is the spherical analog of a conic section (ellipse, parabola, or hyperbola) in the plane, and as in the planar case, a spherical conic can be defined as the locus of points the sum or difference of whose great-circle distances to two foci is constant. By taking the antipodal point to one focus, every spherical ellipse is also a spherical hyperbola, and vice versa. As a space curve, a spherical conic is a quartic, though its orthogonal projections in three principal axes are planar conics. Like planar conics, spherical conics also satisfy a "reflection property": the great-circle arcs from the two foci to any point on the conic have the tangent and normal to the conic at that point as their angle bisectors.
Many theorems about conics in the plane extend to spherical conics. For example, Graves's theorem and Ivory's theorem about confocal conics can also be proven on the sphere; see confocal conic sections about the planar versions.
Just as the arc length of an ellipse is given by an incomplete elliptic integral of the second kind, the arc length of a spherical conic is given by an incomplete elliptic integral of the third kind.
An orthogonal coordinate system in Euclidean space based on concentric spheres and quadratic cones is called a conical or sphero-conical coordinate system. When restricted to the surface of a sphere, the remaining coordinates are confocal spherical conics. Sometimes this is called an elliptic coordinate system on the sphere, by analogy to a planar elliptic coordinate system. Such coordinates can be used in the computation of conformal maps from the sphere to the plane.
Applications
The solution of the Kepler problem in a space of uniform positive curvature is a spherical conic, with a potential proportional to the cotangent of geodesic distance.
Because it preserves distances to a pair of specified points, the two-point equidistant projection maps the family of confocal conics on the sphere onto two families of confocal ellipses and hyperbolae in the plane.
If a portion of the Earth is modeled as spherical, e.g. using the osculating sphere at a point on an ellipsoid of revolution, the hyperbolae used in hyperbolic navigation (which determines position based on the difference in received signal timing from fixed radio transmitters) are spherical conics.
Notes
Further reading
English edition:
Republished in Journal de mathématiques pures et appliquées. Ser. 2. 5: 425-454. PDF from mathdoc.fr.
Conic sections
Spherical curves
Spherical geometry
Euclidean solid geometry
Algebraic curves
Analytic geometry | Spherical conic | [
"Physics"
] | 600 | [
"Spacetime",
"Space",
"Euclidean solid geometry"
] |
68,190,854 | https://en.wikipedia.org/wiki/Beam%20Therapeutics | Beam Therapeutics Inc. is an American biotechnology company conducting research in the field of gene therapies and genome editing. The company is headquartered in Cambridge, Massachusetts. In the development of therapies, the company relies on CRISPR and prime editing, whereby single nucleotides in a DNA sequence can be modified without cutting the DNA, theoretically reducing the likelihood of off-target effects compared to previous CRISPR-based methods.
History
Founded in 2017, the company traces its origins to the Broad Institute of the Massachusetts Institute of Technology and Harvard University. Co-founders include David R. Liu and Feng Zhang. Prior to its IPO, the company raised nearly $1 billion in venture capital from investors. In a February 2020 IPO, the company raised $180 million.
In January 2022, Pfizer and Beam Therapeutics announced a collaboration to develop therapies for rare diseases using CRISPR.
See also
CRISPR Therapeutics
Intellia Therapeutics
Editas Medicine
References
External links
American companies established in 2017
Biotechnology companies of the United States
Gene therapy
Health care companies based in Massachusetts
Pharmaceutical companies of the United States
Life sciences industry
2020 initial public offerings
Companies listed on the Nasdaq | Beam Therapeutics | [
"Engineering",
"Biology"
] | 240 | [
"Life sciences industry",
"Gene therapy",
"Genetic engineering"
] |
68,190,864 | https://en.wikipedia.org/wiki/Agricultural%20weed%20syndrome | The agricultural weed syndrome is the set of common traits which make a plant a successful agricultural weed. Most of these traits are not, themselves, phenotypes but are instead methods of rapid adaptation. So equipped, plants of various origins - invasives, natives, mildly successful marginal weeds of agriculture, weeds of other settings - accumulate other characteristics which allow them to compete in an environment with a high degree of human management.
Nonetheless, some of the syndrome traits are themselves phenotypic.
Syndrome traits
Rapid growth
Efficient use of nutrients
Seed dormancy
Effective seed dispersal, often more aggressive shattering
Vavilovian mimicry including introgression of crop alleles if there are nearby crop relatives
Herbicide resistance
Short life cycle
High fertility
Some of these are the opposite of domestication traits.
Evolution
Insufficient information is available as to the exact contribution of mutations, particular mutation types, pre-existing genetic diversity, specific genes, and introgression to syndrome acquisition. It is also unknown whether we can discern the genetic signatures of adaptation to different weed management regimes from different times.
In some cases domestication alleles may produce weeds that are weedier than the wild parent they were derived from. For example, California wild radish is weedier and more aggressive than Raphanus raphanistrum, despite being merely a combination of R. raphanistrum and R. raphanistrum'''s own subspecies R. r. sativus.
Pre-existing allelic variety which suddenly became more adaptive when the cultivated environment appeared likely has contributed to the success of Amaranthus tuberculatus, A. palmeri, Lolium rigidum and Ipomoea purpurea especially their quick development of herbicide resistance.
On the other hand, novel mutations may be the source herbicide resistance in Echinochloa crus-galli and E. oryzicola, whose worldwide combined populations have developed resistance to nine modes of action.
Some weeds are themselves the descendants of crops, while some are unrelated to any cultivated species. The origins of those arising from cultivars are variously better and worse understood: Weedy Helianthus annuus is well understood as wild/cultivar hybrids, weedy Secale cereale and O. sativa as purely feral crops, Beta vulgaris weeds are highly studied although some further analysis is called for, and at the other end of the spectrum lie Sorghum halepense and weedy races of S. bicolor, weedy congeners of cultivated S. bicolor with complicated interbreeding histories that have yet to be untangled. Recently () teosintes have begun invading Spain and France. DNA testing of Spanish teosinte shows it to be intermediate between Zea mays subsp. mays and Zea mays subsp. mexicana.
Genes
Antioxidant pigmentation:
in Oryza rufipogon and its weedy rice descendants.
Shattering:
in O. rufipogon and its weedy rice descendants, including some new alleles of similar function but entirely new origin.
Germination temperature:
Unknown in weedy rice.
Vavilovian mimicry:
alleles conveying shorter stature, slower growth, and earlier flowering, introgressed from O. sativa cultivars into weedy rice. (May or may not be adaptive, not actually confirmed.)
Herbicide resistance:
Various genes identical to genetically engineered domesticated O. sativa introgressed into weedy rice.
Codon deletion in in A. tuberculatus.
Various alleles of ALS - the acetolactate synthase gene - in a variety of species.
The same amino acid substitution in all 43 genera which have triazine resistance.
Some of these are the same genes as domestication traits, but with alleles of opposite effect.
Example speciesPolygonum aviculare, Plantago lanceolata, Spergularia rubra, Senecio vulgaris, Poa annua, weedy rice, Sorghum weeds including S. halepense and weedy races of S. bicolor, weedy Helianthus annuus''.
See also
Domestication syndrome both in animals and plants
References
Domestication
Agriculture
Weeds
Genetics | Agricultural weed syndrome | [
"Biology"
] | 868 | [
"Domestication",
"Genetics",
"Weeds",
"Pests (organism)",
"Humans and other species"
] |
68,191,120 | https://en.wikipedia.org/wiki/Barnet%20Common | Barnet Common was an area of common land to the south of the town of Chipping Barnet in what is now north London. The Common was created after a wood was cleared in the 16th century and was mostly used by local people to graze their animals. It was the location of a Digger colony and of the Barnet Physic Well at which mineral water was consumed. Part of the Common was enclosed in 1729 and the rest in 1815, leading to development on the north and south sides, and later infilling.
Extent
The Common was created by the clearance of a wood around the 16th century, possibly Southaw or Suthawe wood which at one time belonged to the Abbey of St Albans. It covered the area south of Chipping Barnet's Wood Street and Barnet Road, which run broadly east–west between the town centre and Barnet Gate, and went as far south as Ducks Island, Underhill, and the Dollis Brook.
History
Barnet Physic Well became popular during the second half of the 17th century and there was a Digger colony on the Common in 1649. In the 18th and early 19th century the Common provided pasture for grazing horses which were traded at the Barnet horse fairs.
In 1729, of the Common were enclosed by the Lord of the Manor, the Duke of Chandos. This prevented local people from grazing their animals on that part and in return for the loss of that right, the Duke set up a charity for the poor whereby some land was designated as "fuel land" and the rent from it used to buy winter fuel for the "deserving poor".
The remainder of the Common was finally enclosed in 1815 after which there was development on the north side of the Common in the Wood Street area, such as the six almshouses built by the Eleanor Palmer Trust in 1823 and the construction of the Barnet Union Workhouse in 1836–37 on Wellhouse Lane which led to the Physic Well. Housing was built on the south side at Ducks (or Duck) Island.
In 1876, James Thorne wrote in his Handbook to the Environs of London that the area around the former Common had "increased considerably" since the opening of the railway on the site of the former Barnet race course in 1872.
Later development in the area includes the construction of Barnet Hospital and its predecessors on the site of the former workhouse, and the creation of Barnet Recreation Ground in the 1880s from some of the last remaining common land. It was of a formal design with winding serpentine walks and was later renamed Ravenscroft Gardens after local philanthropist James Ravenscroft. Bell's Hill Burial Ground was opened in 1895.
Barnet Physic Well
The waters of the Barnet Physic Well, located on the Common, were recommended as a remedy for various medical complaints in William Camden's Brittania (1586) as "The Barnet Whey" but only became well-known as a source of mineral water during the second half of the 17th century. In 1652 the well was described as producing "an excellent purging water" that worked as well as that of Epsom water but with half the quantity.
A well-house was built in 1656 and in 1661 the Well was described as "famous" by Joshua Childrey in his book Natural Rarities of England, Scotland and Wales. In 1662, Thomas Fuller in Worthies of England hoped that its waters would save as many lives as were lost in the Battle of Barnet, and Samuel Pepys recorded his visits in 1664 and 1667 in his Diary, drinking five glasses of the water on his first visit which caused him to need to urinate "seven or eight times upon the road" home. The Well was also mentioned by Daniel Defoe in his Tour of the Whole Island of Britain (1720s). It was popular into the 18th century but subsequently declined until being restored in the 20th century. A new Tudor-style well-house was built in 1937 which was restored in 2018.
The well has been listed Grade II on the National Heritage List for England since 1983.
See also
Monken Hadley Common
References
External links
Common land in England
Chipping Barnet
Water wells | Barnet Common | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 832 | [
"Hydrology",
"Water wells",
"Environmental engineering"
] |
68,191,395 | https://en.wikipedia.org/wiki/Environmental%20Research%20Institute | The Environmental Research Institute (ERI) is a research institute based in the town centre of Thurso, Scotland. It is a part of North Highland College, which is one of the University of the Highlands and Islands' partners (UHI). The institute was officially opened on 9 May 2000 by Jamie Stone MSP. The project was funded by The European Regional Development Fund and the Millennium Commission. The ERI is also involved in the development and delivery of Master's and Ph.D. programmes. The institute specifically works on environmental contamination and ecological health, renewable energy and the environment, and carbon, water, climate studies.
References
External links
Research institutes in Scotland
Environmental research institutes
University of the Highlands and Islands
Thurso | Environmental Research Institute | [
"Environmental_science"
] | 149 | [
"Environmental research institutes",
"Environmental research"
] |
68,193,269 | https://en.wikipedia.org/wiki/Project%20Santa%20Barbara | Project Santa Barbara was a missile program developed under the administration of Philippine president Ferdinand Marcos (1965–86) during the Cold War. The first successful launch was in 1972. The project was discontinued due to undisclosed reasons.
Background
Project Santa Barbara was initiated by the administration of Philippine president Ferdinand Marcos and it involved the Philippine Navy and a group of scientists. It was conceived amidst the United States withdrawal of its armed forces in Indochina and in anticipation that the US would also withdraw its forces stationed in the Philippines.
Under the program, different types of missiles were developed which are intended to intercept land, sea, and air-based threats. There were also plans to export missiles developed under the program to friendly countries.
One of the missiles developed was the Bongbong rocket, named after the moniker of President Marcos' son Ferdinand Jr. The National Aeronautics and Space Administration of the United States described the weapon as the Philippines' first liquid-propellant rocket. The associated weaponry system of the Bongbong rocket is similar to the Soviet unguided artillery Katyusha. The 37 dynamic tests were conducted, with most of the test conducted on Caballo Island. Four of the test were made in Fort Magsaysay.
The first successful launch under the project involved the Bongbong rocket. The launch was made on March 12, 1972 with the rocket retrieved from the South China Sea.
The project was discontinued due to undisclosed reasons.
References
External links
https://www.youtube.com/watch?v=RxHtd1XYaCw - A 1973 parade featuring the Bongbong rocket archived in Ghostarchive.org on 3 May 2022
Rockets and missiles
Ferdinand Marcos
Experimental rockets
Philippine Army
Secret military programs | Project Santa Barbara | [
"Engineering"
] | 345 | [
"Military projects",
"Secret military programs"
] |
68,193,323 | https://en.wikipedia.org/wiki/Electrical%20device | Electrical devices or electric devices are devices that functionally rely on electric energy (AC or DC) to operate their core parts (electric motors, transformers, lighting, rechargeable batteries, control electronics). They can be contrasted with traditional mechanical devices which depend on different power sources like fuels or human physical strength. Electronic devices are a specialized kind of electrical devices in which electric power is predominantly used for data processing rather than the generation of mechanical forces. To better differentiate between both classes, electric devices that emphasize physical work are also called electromechanical. Mechatronics accentuates the intersection of both fields.
Together, electronic and electric devices, their development, maintenance, and power supply comprise the subject of electrical engineering.
The majority of electric devices in households is stationary and — due to their considerable power consumption — relies on electrical installation, especially electric outlets instead of small electric generators, batteries, rechargeable or not.
Due to their dependence on electric power sources, in general well-evolved power grids, electric devices and their power consumption pattern have moved into the focus of smart metering.
Electrical equipment
Electrical equipment includes any machine powered by electricity. It usually consists of an enclosure, a variety of electrical components, and often a power switch. Examples of these include:
Lighting
Major appliance
Small appliances
IT equipment (computers, printers etc.)
Motors, pumps and HVAC Systems
More specifically, electrical equipment refers to the individual components of an electrical distribution system. These components may involve:
Electric switchboards
Distribution boards
Circuit breakers and disconnects
Transformers
Electricity meter
See also
Electrical equipment in hazardous areas
Electrical equipment
Home appliance
Power transmission
Electrical room
Grounding kit
List of largest manufacturing companies by revenue
References
Literature
Electrical engineering
Electric power distribution | Electrical device | [
"Engineering"
] | 351 | [
"Electrical engineering",
"Electrical equipment"
] |
68,193,807 | https://en.wikipedia.org/wiki/Mustankallio%20water%20tower | Mustankallio water tower lies in the Kiveriö district of Lahti, Finland, and stands tall. Completed by a local company in 1963, it includes two water reservoirs, a penthouse meeting facility complete with sauna, and a viewing platform. The design, which features pre-stressed concrete elements and asbestos cement cladding, was a departure from the steel water tower structures commonly built in the region. When commissioned, its original name was the Metelinmäki Water Tower. It has been described as crocus-like in appearance and complimented on its elegance.
Design and construction
Water towers in the region, many of which were built in the 19th century, had previously been built from steel. They have been described as "ugly and uninspiring" and "marring the skyline". This structure, designed by Ing. Büro Paavo Simula and Company, was intended to be more aesthetic to minimise its effect on the visual environment. It stands on Mustankallio hill.
The tower was completed in 1963 by local construction firm B&K. It is constructed of pre-stressed concrete elements built locally, under license from the German Dyckerhoff & Widmann (Dywidag) company. The main body contains two drinking water reservoirs with a combined capacity of , protected from freezing by a lining of mineral wool. The exterior is clad with asbestos cement panels.
The structure stands tall; the top of the tower is above the nearby Lake Vesijärvi and above sea level. The uppermost portion of the tower is around in diameter. The structure has received praise for its "striking appearance" and "elegant lines". The design has been described as crocus-like.
Use
Lahti Aqua, a company owned by the city of Lahti, owns the tower and uses it to store water for distribution to the town. At night water is pumped into the tank from lower-level storage, during the day water is drained via gravity feed and hydrostatic pressure from the tank for distribution to Mustankallio, Kiveriö, Tonttila and Pyhättömänmäki.
The tower contains a viewing platform with good views across the town. The tower also contains a meeting room capable of housing 30 to 40 people, a sauna that can accommodate 15, a lounge, kitchen, toilet and showers. The facilities are available for rent between 8 a.m. and midnight. Small-sized lifts offer access to the facilities.
In 2015, the facade exterior panels were replaced.
It is part of the motif in the 2021 Ironman 70.3 Ironman Triathlon Finland medal.
See also
Kuwait Water Towers, for an organic "mushroom farm" look by Swedish designers and engineers
List of tallest towers
References
External links
Asbestos
Buildings and structures in Päijät-Häme
Towers completed in 1963
Water towers in Finland | Mustankallio water tower | [
"Environmental_science"
] | 585 | [
"Toxicology",
"Asbestos"
] |
68,193,810 | https://en.wikipedia.org/wiki/Super%20basin | Super basin is a term in Petroleum Geology referring to the most important basins for the oil industry. The top 30 super basin contain about 57% of the biggest oil fields in the world. The term was coined in 2016 by Bob Fryklund and Pete Stark.
Definition
In 2016, Bob Fryklund and Pete Stark defined "super basin" combining commerciality, geoscience architecture, infrastructure, and above-ground issues. According to the original paper published in IHS Markit, a basin must count with at least five barrels of oil equivalent (BBOe) produced and at the same volume of recoverable remaining reserves; two or more petroleum systems or source rocks; stacked reservoirs; existing infrastructure and oil field services; and good access to markets. A characteristic is richness measured as the total volume of hydrocarbons per square kilometer.
Location
The US Permian Basin is the archetypal onshore super basin. However, other basins are located around the world, such as South America's Neuquen Basin in 2018, which counts with favorable regulations and government support. In Mexico, there are potentially ripe basins. Offshore basins in the North Sea, Brazil, and the Gulf of Mexico are benefiting from geophysical enhancements. The top 30 super basin contain about 57% of the biggest oil fields in the world.
List of super basins
The top 30 super basin contain about 57% of the biggest oil fields in the world. Some of the super basins in the world are:
References
Petroleum_industry
Oil_exploration
Oil_fields | Super basin | [
"Chemistry"
] | 311 | [
"Chemical process engineering",
"Petroleum",
"Petroleum industry"
] |
68,194,137 | https://en.wikipedia.org/wiki/Total%20mycosynthesis | Total mycosynthesis is the combination of the use of a filamentous fungal host organism with a genetic expression system that allows the assembly and controlled expression of one or more biosynthetic genes. Total mycosynthesis involves the reconstruction and/or engineering of biosynthetic pathways for the production of secondary metabolites. It is competitive with chemical total synthesis. It can be used both for the production of known natural products, and for the engineering of pathways to produce new compounds or pathway intermediates.Examples include the total mycosynthesis of tenellin where the tenS, tenC, tenA and tenB genes were transferred from Beauveria bassiana to the expression host Aspergillus oryzae. The expression system allows the engineering of TenS to control chain-length and methylation pattern.
Examples
References
Mycology | Total mycosynthesis | [
"Biology"
] | 175 | [
"Mycology"
] |
68,194,734 | https://en.wikipedia.org/wiki/Corepresentations%20of%20unitary%20and%20antiunitary%20groups | In quantum mechanics, symmetry operations are of importance in giving information about solutions to a system. Typically these operations form a mathematical group, such as the rotation group SO(3) for spherically symmetric potentials. The representation theory of these groups leads to irreducible representations, which for SO(3) gives the angular momentum ket vectors of the system.
Standard representation theory uses linear operators. However, some operators of physical importance such as time reversal are antilinear, and including these in the symmetry group leads to groups including both unitary and antiunitary operators.
This article is about corepresentation theory, the equivalent of representation theory for these groups. It is mainly used in the theoretical study of magnetic structure but is also relevant to particle physics due to CPT symmetry. It gives basic results, the relation to ordinary representation theory and some references to applications.
Corepresentations of unitary/antiunitary groups
Eugene Wigner showed that a symmetry operation S of a Hamiltonian is represented in quantum mechanics either by a unitary operator, S = U, or an antiunitary one, S = UK where U is unitary, and K denotes complex conjugation. Antiunitary operators arise in quantum mechanics due to the time reversal operator
If the set of symmetry operations (both unitary and antiunitary) forms a group, then it is commonly known as a magnetic group and many of these are described in magnetic space groups.
A group of unitary operators may be represented by a group representation. Due to the presence of antiunitary operators this must be replaced by Wigner's corepresentation theory.
Definition
Let G be a group with a subgroup H of index 2. A corepresentation is a homomorphism into a group of operators over a vector space over the complex numbers where for all u in H the image of u is a linear operator and for all a in the coset G-H the image of a is antilinear (where '*' means complex conjugation):
Properties
As this is a homomorphism
Reducibility
Two corepresentations are equivalent if there is a matrix V
Just like representations, a corepresentation is reducible if there is a proper subspace invariant under the operations of the corepresentation. If the corepresentation is given by matrices, it is reducible if it is equivalent to a corepresentation with each matrix in block diagonal form.
If the corepresentation is not reducible, then it is irreducible.
Schur's lemma
Schur's lemma for irreducible representations over the complex numbers states that if a matrix commutes with all matrices of the representation then it is a (complex) multiple of the identity matrix, that is, the set of commuting matrices is isomorphic to the complex numbers . The equivalent of Schur's lemma for irreducible corepresentations is that the set of commuting matrices is isomorphic to , or the quaternions . Using the intertwining number over the real numbers, this may be expressed as an intertwining number of 1, 2 or 4.
Relation to representations of the linear subgroup
Typically, irreducible corepresentations are related to the irreducible representations of the linear subgroup H. Let be an irreducible (ordinary) representation of he linear subgroup H. Form the sum over all the antilinear operators of the square of the character of each of these operators:
and set for an arbitrary element .
There are three cases, distinguished by the character test eq 7.3.51 of Cracknell and Bradley.
Type(a) If S = |H| (the intertwining number is one) then D is an irreducible corepresentation of the same dimension as with
Type(b) S = -|H| (the intertwining number is four) then D is an irreducible representation formed from two 'copies' of
Type(c) If S = 0 (the intertwining number is two), then D is an irreducible corepresentation formed from two inequivalent representations and where
Cracknell and Bradley show how to use these to construct corepresentations for the magnetic point groups, while Cracknell and Wong give more explicit tables for the double magnetic groups.
Character theory of corepresentations
Standard representation theory for finite groups has a square character table with row and column orthogonality properties. With a slightly different definition of conjugacy classes and use of the intertwining number, a square character table with similar orthogonality properties also exists for the corepresentations of finite magnetic groups.
Based on this character table, a character theory mirroring that of representation theory has been developed.
See also
References
Representation theory of groups
Quantum mechanics | Corepresentations of unitary and antiunitary groups | [
"Physics"
] | 979 | [
"Theoretical physics",
"Quantum mechanics"
] |
68,195,259 | https://en.wikipedia.org/wiki/Edwin%20C.%20Webb | Edwin Clifford Webb (21 May 1921 – 17 January 2006) was a British biochemist.
Life and career
Webb was born in Dorset and educated at Poole Grammar School and Clare College, Cambridge, where he studied nerve gases and graduated with a first-class BA in Natural Sciences in 1942. He remained at Cambridge for his doctorate, where he was a Beit Fellow. There he worked in the laboratory of Malcolm Dixon, collaborating with him in the study of enzymes. Together, they wrote a classic textbook on the subject, Enzymes, which was first published by Longmans in 1958, Webb subsequently took a chair in biochemistry at the University of Queensland but continued to collaborate with Dixon on further editions. In 1970, he became the deputy vice-chancellor at Queensland and in 1975 he became the second vice-chancellor of Macquarie University. He retired in 1986 but continued to work on the enzyme list of the International Union of Biochemistry and Molecular Biology (IUBMB) while living in Townsville.
Research
Cambridge
Webb's first paper was written with Kenneth Bailey on yeast pyrophosphatase, the first of many papers on enzymes. It was followed by several papers on nerve gases, for example on British anti-lewisite with Ruth van Heyningen. Research collaboration with Malcolm Dixon began with a study of phosphotransferases, and continued with other work, both theoretical and experimental.
Queensland
After moving to Queensland Webb collaborated with Burt Zerner on Jack bean urease, starting with a study of its purification and assay, followed by other papers on the same enzyme. He also worked with Zerner on other enzymes, including carboxylesterases.
Nomenclature
Webb's interest in biochemical nomenclature started early in his career, and after the IUBMB compilation was published for the last time as a printed book he wrote a retrospective article about it.
References
1921 births
2006 deaths
Academics of the University of Cambridge
Alumni of Clare College, Cambridge
20th-century biochemists
20th-century British chemists
Academic staff of Macquarie University
People from Dorset
Academic staff of the University of Queensland
21st-century biochemists | Edwin C. Webb | [
"Chemistry"
] | 423 | [
"Biochemistry stubs",
"Biochemists",
"Biochemist stubs"
] |
68,195,735 | https://en.wikipedia.org/wiki/Matrix%20sign%20function | In mathematics, the matrix sign function is a matrix function on square matrices analogous to the complex sign function.
It was introduced by J.D. Roberts in 1971 as a tool for model reduction and for solving Lyapunov and Algebraic Riccati equation in a technical report of Cambridge University, which was later published in a journal in 1980.
Definition
The matrix sign function is a generalization of the complex signum function
to the matrix valued analogue . Although the sign function is not analytic, the matrix function is well defined for all matrices that have no eigenvalue on the imaginary axis, see for example the Jordan-form-based definition (where the derivatives are all zero).
Properties
Theorem: Let , then .
Theorem: Let , then is diagonalizable and has eigenvalues that are .
Theorem: Let , then is a projector onto the invariant subspace associated with the eigenvalues in the right-half plane, and analogously for and the left-half plane.
Theorem: Let , and be a Jordan decomposition such that corresponds to eigenvalues with positive real part and to eigenvalue with negative real part. Then , where and are identity matrices of sizes corresponding to and , respectively.
Computational methods
The function can be computed with generic methods for matrix functions, but there are also specialized methods.
Newton iteration
The Newton iteration can be derived by observing that , which in terms of matrices can be written as , where we use the matrix square root. If we apply the Babylonian method to compute the square root of the matrix , that is, the iteration , and define the new iterate , we arrive at the iteration
,
where typically . Convergence is global, and locally it is quadratic.
The Newton iteration uses the explicit inverse of the iterates .
Newton–Schulz iteration
To avoid the need of an explicit inverse used in the Newton iteration, the inverse can be approximated with one step of the Newton iteration for the inverse, , derived by Schulz(de) in 1933. Substituting this approximation into the previous method, the new method becomes
.
Convergence is (still) quadratic, but only local (guaranteed for ).
Applications
Solutions of Sylvester equations
Theorem: Let and assume that and are stable, then the unique solution to the Sylvester equation, , is given by such that
Proof sketch: The result follows from the similarity transform
since
due to the stability of and .
The theorem is, naturally, also applicable to the Lyapunov equation. However, due to the structure the Newton iteration simplifies to only involving inverses of and .
Solutions of algebraic Riccati equations
There is a similar result applicable to the algebraic Riccati equation, . Define as
Under the assumption that are Hermitian and there exists a unique stabilizing solution, in the sense that is stable, that solution is given by the over-determined, but consistent, linear system
Proof sketch: The similarity transform
and the stability of implies that
for some matrix .
Computations of matrix square-root
The Denman–Beavers iteration for the square root of a matrix can be derived from the Newton iteration for the matrix sign function by noticing that is a degenerate algebraic Riccati equation and by definition a solution is the square root of .
References
Matrix theory
Linear algebra | Matrix sign function | [
"Mathematics"
] | 667 | [
"Linear algebra",
"Algebra"
] |
68,195,873 | https://en.wikipedia.org/wiki/Boletus%20orientialbus | Boletus orientialbus is a species of porcini-like fungus native to Fujian Province in Southeastern China, where it grows under trees of the genera Lithocarpus and Castanopsis in subtropical climates.
References
orientialbus
Fungi of China
Fungi described in 2014
Fungus species | Boletus orientialbus | [
"Biology"
] | 58 | [
"Fungi",
"Fungus species"
] |
68,195,991 | https://en.wikipedia.org/wiki/Boletus%20monilifer | Boletus monilifer is a species of porcini-like fungus native to Yunnan Province in Southwestern China, where it grows under trees of the genera Lithocarpus, Quercus and Castanopsis in subtropical montane forests.
References
monilifer
Fungi of China
Fungi described in 2016
Fungus species | Boletus monilifer | [
"Biology"
] | 62 | [
"Fungi",
"Fungus species"
] |
68,198,111 | https://en.wikipedia.org/wiki/Western%20meadow%20vole | The western meadow vole (Microtus drummondii) is a species of North American vole found in western North America, the midwestern United States, western Ontario, Canada, and formerly in Mexico. It was previously considered conspecific with the eastern meadow vole (M. pennsylvanicus), but genetic studies indicate that it is a distinct species. It is sometimes called the field mouse or meadow mouse, although these common names can also refer to other species.
Distribution
It ranges from Ontario west to Alaska, and south to Missouri, north-central Nebraska, the northern half of Wyoming, and central Washington south through Idaho into north-central Utah. A disjunct subset of its range occurs from central Colorado to northwestern New Mexico. An isolated population was formerly found in Chihuahua, Mexico, but has since been extirpated. The United States portion of the Souris River is alternately known as the Mouse River because of the large numbers of field mice that lived along its banks.
Plant communities
In eastern Washington and northern Idaho, meadow voles are found in relative abundance in sedge (Carex sp.) fens, but not in adjacent cedar (Thuja sp.)-hemlock (Tsuga sp.), Douglas-fir (Pseudotsuga menziesii), or ponderosa pine (Pinus ponderosa) forests. Meadow voles are also absent from fescue (Festuca sp.)-snowberry (Symphoricarpos sp.) associations. Moisture may be a major factor in habitat use; possibly the presence of free water is a deciding factor.
In southeastern Montana, western meadow voles were the second-most abundant small mammal (after deer mice, Peromyscus maniculatus) in riparian areas within big sagebrush (Artemisia tridentata)-buffalo grass (Bouteloua dactyloides) habitats. Western meadow voles are listed as riparian-dependent vertebrates in the Snake River drainage of Wyoming. In a compilation of 11 studies on small mammals, western meadow voles were reported in only three of 29 sites in subalpine forests of the central Rocky Mountains. Their range extensions were likely to be related to irrigation practices. They are now common in hayfields, pastures, and along ditches in the Rocky Mountain states. In Pipestone National Monument, Minnesota, western meadow voles were present in riparian shrublands, tallgrass prairie, and other habitats.
Habitat
In an Iowa prairie restoration project, meadow voles experienced an initial population increase during the initial stage of vegetation succession (old field dominated by foxtail grass (Setaria spp.), red clover (Trifolium pratense), annual ragweed (Ambrosia artemisiifolia), alfalfa (Medicago sativa), and thistles (Cirsium spp.). However, populations reached their peak abundance during the perennial grass stage of succession from old field to tallgrass prairie. Meadow vole habitat devoid of tree cover and grasses dominated the herb layer. with low tolerance for habitat variation (i. e., a species that is intolerant of variations in habitat, is restricted to few habitats, and/or uses habitats less evenly than tolerant species).
In most areas, meadow voles clearly prefer habitat with dense vegetation. In tallgrass prairie at Pipestone National Monument, they were positively associated with dense vegetation and litter. The variables important to meadow vole habitat in Virginia include vegetative cover reaching a height of 8 to 16 inches (20–41 cm) and presence of litter. Meadow voles appeared to be randomly distributed within a grassland habitat in southern Quebec. Grant and Morris were not able to establish any association of meadow vole abundance with particular plant species. They were also unable to distinguish between food and cover as the determining factor in meadow vole association with dense vegetation. In South Dakota, meadow voles prefer grasslands to Rocky Mountain juniper (Juniperus scopulorum) woodlands. In New Mexico, meadow voles were captured in stands of grasses, wild rose (Rosa sp.), prickly pear (Opuntia sp.), and various forbs; meadow voles were also captured in wet areas with tall marsh grasses.
Open habitat with a thick mat of perennial grass favors voles. In west-central Illinois, they were the most common small mammals on Indian grass (Sorghastrum nutans)-dominated and switchgrass (Panicum virgatum)-dominated study plots. They were present in very low numbers on orchard grass (Dactylis glomerata)-dominated plots. The most stable population occurred on unburned big bluestem (Andropogon gerardii)-dominated plots. In Ontario, meadow voles and white-footed mice (Peromyscus leucopus) occur together in ecotones. Meadow voles were the most common small mammals in oak savanna/tallgrass prairie dominated by northern pin oak (Quercus ellipsoidalis) and grasses including bluejoint reedgrass (Calamagrostis canadensis), prairie cordgrass (Sporobolus michauxianus), big bluestem, switchgrass, and Indian grass.
In Michigan, strip clearcuts in a conifer swamp resulted in an increase in the relative abundance of meadow voles. They were most abundant in clearcut strip interiors and least abundant in uncut strip interiors. Slash burning did not appear to affect meadow vole numbers about 1.5 years after treatment.
Predators
Birds not usually considered predators of mice do take voles; examples include gulls (Larus sp.), northern shrikes (Larius borealis), black-billed magpies (Pica hudsonica), common ravens (Corvus corax), American crows (C. brachyrhynchos), great blue herons (Ardea herodias), and American bitterns (Botaurus lentiginosus).
Major mammalian predators include the badger (Taxidea taxus), striped skunk (Mephitis mephitis), weasels (Mustela and Neogale sp.), martens (Martes americana and M. caurina), domestic dogs (Canis familiaris), domestic cats (Felis catus) and mountain lions (Puma concolor). Other animals reported to have ingested voles include trout (Salmo sp.), Pacific giant salamanders (Dicampton ensatus), garter snakes (Thamnophis sp.), yellow-bellied racers (Coluber constrictor flaviventris), gopher snakes (Pituophis melanoleucas), plains rattlesnakes (Crotalus viridis), and rubber boas (Charina bottae).
In northern prairie wetlands, meadow voles are a large portion of the diets of red foxes (Vulpes vulpes), American mink (Neogale vison), short-eared owls (Asio flammeus), and northern harriers (Circus cyaneus). Voles are frequently taken by racers (Coluber sp.) since both often use the same burrows.
Management
In forest plantations in British Columbia, an apparently abundant (not measured) meadow vole population was associated with a high rate of "not sufficient regeneration"; damage to tree seedlings was attributed to meadow voles and lemmings (Synaptomys sp.).
The cycle of meadow vole abundance is an important proximate factor affecting the life histories of its major predators. Meadow voles are usually the most abundant small mammals in northern prairie wetlands, often exceeding 40% of all individual small mammals present. Numbers of short-eared owls, northern harriers, rough-legged hawks (Buteo lagopus), coyotes (Canis latrans), and red foxes were directly related to large numbers of meadow voles in a field in Wisconsin. Predator numbers are positively associated with meadow vole abundance.
Threats
The species depends heavily on mesic habitats, and in areas on the periphery of its range, which contain distinctive and divergent subspecies, populations may be lost if the wetness of the habitats changes. A distinct Pleistocene relict subspecies, M. d. chihuahuensis, the Chihuahuan vole, was also found in Chihuahua, Mexico, but has not been recorded since 1988 after its habitat was degraded by recreational activities and especially overgrazing, and eventually the marsh was completely drained by the early 2000s. This subspecies displayed notable divergence from other populations and was highly isolated from any others, and would be considered a distinctive subspecies. In addition, two other populations in New Mexico appear to have been extirpated in recent times, likely as a consequence of climate change-induced drying and overgrazing. Due to the heavy association between meadow voles and mesic habitats, they are especially at risk from drying trends in areas at the peripheries of their range, leaving many of these populations at heavy risk of extirpation.
References
Western meadow
Rodents of Canada
Rodents of the United States
Bioindicators
Fauna of Alaska
Fauna of the Plains-Midwest (United States)
Mammals described in 1854
Taxa named by John James Audubon
Taxa named by John Bachman | Western meadow vole | [
"Chemistry",
"Environmental_science"
] | 1,927 | [
"Bioindicators",
"Environmental chemistry"
] |
68,198,138 | https://en.wikipedia.org/wiki/Diana%20Northup | Diana E. Northup is an American microbiologist, speleologist, ecologist, Visiting Professor of Biology, and Professor Emerita of Library Sciences with the University of New Mexico. Her research focuses on the microbial ecology of caves around the world. Dr. Northup is a Fellow of the National Speleological Society and the Cave Research Foundation. She wrote the Wiley textbook Microbial Ecology. She was awarded the National Speleological Society Science Prize in 2013.
Early life and education
Northup was an undergraduate student at West Virginia University, where she studied political science. She moved to the University of Illinois Urbana-Champaign for graduate studies, where she earned a Master's of Library Science in 1972. Northup moved to the University of New Mexico, where she earned a Master's degree in biology in 1988. She remained at the University of New Mexico for her doctoral research, where she studied the geomicrobiology of caves.
Research and career
Northup is a visiting associate professor at the University of New Mexico where she started the Subsurface Life In Mineral Environments (SLIME) team. In particular, Northup studies the colorful ferromanganese deposits that line the walls of Lechuguilla and Spider Cave in Carlsbad Caverns National Park. Her work on the Lechuguilla Cave was featured in a PBS Nova episode, "The Mysterious Life of Caves." She is also interested in the hydrogen sulfide cave known as'Cueva de las Sardinas' or 'Cueva de Villa Luz' in Tabasco.
Northup was elected Fellow of the National Speleological Society in 1992, awarded their Science Prize in 2013, and presented a Luminary talk in 2015.
In 2011, Northup gave a TEDx talk about how she got started in caving and how that influences her mentoring of students.
Selected publications
Read, Kaitlin J.H., Melim, Leslie A., Winter, Ara S., Northup, Diana. "Bacterial Diversity in Vadose Cave Pools: Evidence for Isolated Ecosystems". Journal of Cave and Karst Studies. v. 83, no. 4, p. 163-188. DOI:10.4311/2020MB0120
Books
References
Living people
Speleologists
University of New Mexico faculty
University of New Mexico alumni
Geomicrobiologists
American women microbiologists
Geochemists
Year of birth missing (living people) | Diana Northup | [
"Chemistry"
] | 495 | [
"Geochemists"
] |
76,994,773 | https://en.wikipedia.org/wiki/Alexander%20Eibner | Alexander Paul Friedrich Eibner (1862–1935), was a German chemist, painter, and educator. He was known for his technical painting techniques.
Early life and education
Alexander Eibner, was born on September 11, 1862, in Munich. He was the son of Luise Weissenberger, and painter Friedrich Eibner. Eibner studied chemistry at the Technical University of Munich, under Wilhelm von Miller and he obtained a doctorate degree in 1892.
Career
By 1894, he qualified as a professor, and began researching aromaticity in organic chemistry. He studied the bleaching of pigment of Prussian Blue using zinc oxide. Through that research he introduced the concept of photocatalysis in 1911.
In 1903, Eibner became assistant to chemist at the newly founded Research Institute and Information Center for Painting Techniques, promoting the scientific study of the nature and the properties of painting materials. Starting in 1907, Eibner lead the Research Institute and Information Center for Painting Techniques, which closed after his death.
He died on May 1, 1935, in Munich. He is buried at Alter Südfriedhof cemetery, near his father.
References
1862 births
1935 deaths
19th-century German chemists
19th-century German painters
Academic staff of the Technical University of Munich
German male painters
German organic chemists
Scientists from Munich
Technical University of Munich alumni | Alexander Eibner | [
"Chemistry"
] | 271 | [
"Organic chemists",
"German organic chemists"
] |
76,995,097 | https://en.wikipedia.org/wiki/4D%20N%20%3D%201%20supergravity | In supersymmetry, 4D supergravity is the theory of supergravity in four dimensions with a single supercharge. It contains exactly one supergravity multiplet, consisting of a graviton and a gravitino, but can also have an arbitrary number of chiral and vector supermultiplets, with supersymmetry imposing stringent constraints on how these can interact. The theory is primarily determined by three functions, those being the Kähler potential, the superpotential, and the gauge kinetic matrix. Many of its properties are strongly linked to the geometry associated to the scalar fields in the chiral multiplets. After the simplest form of this supergravity was first discovered, a theory involving only the supergravity multiplet, the following years saw an effort to incorporate different matter multiplets, with the general action being derived in 1982 by Eugène Cremmer, Sergio Ferrara, Luciano Girardello, and Antonie Van Proeyen.
This theory plays an important role in many Beyond the Standard Model scenarios. Notably, many four-dimensional models derived from string theory are of this type, with supersymmetry providing crucial control over the compactification procedure. The absence of low-energy supersymmetry in our universe requires that supersymmetry is broken at some scale. Supergravity provides new mechanisms for supersymmetry breaking that are absent in global supersymmetry, such as gravity mediation. Another useful feature is the presence of no-scale models, which have numerous applications in cosmology.
History
Supergravity was first discovered in 1976 in the form of pure 4D supergravity. This was a theory of only the graviton and its superpartner, the gravitino. The first extension to also couple matter fields to the theory was acquired by adding Maxwell and Yang–Mills fields. Adding chiral multiplets proved harder, but the first step was to successfully add a single massless chiral multiplet in 1977. This was then extended the next year to adding more chiral multiplets in the form of the non-linear sigma model. All these theories were constructed using the iterative Noether method, which does not lend itself towards deriving more general matter coupled actions due to being very tedious.
The development of tensor calculus techniques allowed for the construction of supergravity actions more efficiently. Using this formalism, the general four-dimensional matter-coupled supergravity action was constructed in 1982 by Eugène Cremmer, Sergio Ferrara, Luciano Girardello, and Antonie Van Proeyen. It was also derived by Jonathan Bagger shortly after using superspace techniques, with this work highlighting important geometric features of the theory. Around this time two other features of the models were identified. These are the Kähler–Hodge structure present in theory and the presence and importance of no-scale models.
Overview
The particle content of a general four-dimensional supergravity consists of a single supergravity multiplet and an arbitrary number of chiral multiplets and gauge multiplets. The supergravity multiplet contains the spin-2 graviton describing fluctuations in the spacetime metric , along with a spin-3/2 Majorana gravitino , where the spinor index is often left implicit. The chiral multiplets , indexed by lower-case Latin indices , each consist of a scalar and its Majorana superpartner . Similarly, the gauge multiplets consist of a Yang–Mills gauge field and its Majorana superpartner the gaugino , with these multiplets indexed by capital Latin letters .
One of the most important structures of the theory is the scalar manifold, which is the field space manifold whose coordinates are the scalars. Global supersymmetry implies that this manifold must be a special type of complex manifold known as a Kähler manifold. Local supersymmetry of supergravity further restricts its form to be that of a Kähler–Hodge manifold.
The theory is primarily described by three arbitrary functions of the scalar fields, the first being the Kähler potential which fixes the metric on the scalar manifold. The second is the superpotential, which is an arbitrary holomorphic function that fixes a number of aspects of the action such as the scalar field F-term potential along with the fermion mass terms and Yukawa couplings. Lastly, there is the gauge kinetic matrix whose components are holomorphic functions determining, among other aspects, the gauge kinetic term, the theta term, and the D-term potential.
Additionally, the supergravity may be gauged or ungauged. In ungauged supergravity, any gauge transformations present can only act on abelian gauge fields. Meanwhile, a gauged supergravity can be acquired from an ungauged one by gauging some of its global symmetries, which can cause the scalars or fermions to also transform under gauge transformations and result in non-abelian gauge fields. Besides local supersymmetry transformations, local Lorentz transformations, and gauge transformations, the action must also be invariant under Kähler transformations , where is an arbitrary holomorphic function of the scalar fields.
Construction
Historically, the first approach to constructing supergravity theories was the iterative Noether formalism which uses a globally supersymmetric theory as a starting point. Its Lagrangian is then coupled to pure supergravity through the term which couples the gravitino to the supercurrent of the original theory, with everything also Lorentz covariantized to make it valid in curved spacetime. This candidate theory is then varied with respect to local supersymmetry transformations yielding some nonvanishing part. The Lagrangian is then modified by adding to it new terms that cancel this variation, at the expense of introducing new nonvanishing variations. More terms are the introduced to cancel these, and the procedure is repeated until the Lagrangian is fully invariant.
Since the Noether formalism proved to be very tedious and inefficient, more efficient construction techniques were developed. The first formalism that successfully constructed the general matter-coupled 4D supergravity theory was the tensor calculus formalism. Another early approach was the superspace approach which generalizes the notion of superspace to a curved superspace whose tangent space at each point behaves like the traditional flat superspace from global supersymmetry. The general invariant action can then be constructed in terms of the superfields, which can then be expanded in terms of the component fields to give the component form of the supergravity action.
Another approach is the superconformal tensor calculus approach which uses conformal symmetry as a tool to construct supergravity actions that do not themselves have any conformal symmetry. This is done by first constructing a gauge theory using the superconformal algebra. This theory contains extra fields and symmetries, but they can be eliminated using constraints or through gauge fixing to yield Poincaré supergravity without conformal symmetry.
The superconformal and superspace ideas have also been combined into a number of different supergravity conformal superspace formulations. The direct generalization of the original on-shell superspace approach is the Grimm–Wess–Zumino formalism formulated in 1979. There is also the superspace formalism proposed by Paul Howe in 1981. Lastly, the conformal superspace approach formulated in 2010 has the convenient property that any other formulation of conformal supergravity is either equivalent to it or can otherwise be obtained from a partial gauge fixing.
Symmetries
Scalar manifold and Kähler transformations
Supergravity often uses Majorana spinor notation over that of Weyl spinors since four-component notation is easier to use in curved spacetime. Weyl spinors can be acquired as projections of a Majorana spinor , with the left and right handed Weyl spinors denoted by .
Complex scalars in the chiral multiplets act as coordinates on a complex manifold in the sense of the nonlinear sigma model, known as the scalar manifold. In supersymmetric theories these manifolds are imprinted with additional geometric constraints arising from the supersymmetry transformations. In supergravity this manifold may be compact or noncompact, while for supergravities it is necessarily noncompact.
Global supersymmetry already restricts the manifold to be a Kähler manifolds. These are a type of complex manifold, which roughly speaking are manifolds that look locally like and whose transition maps are holomorphic functions. Complex manifolds are also Hermitian manifolds if they admit a well-defined metric whose only nonvanishing components are the components, where the bar over the index denotes the conjugate coordinate . More generally, a bar over scalars denotes complex conjugation while for spinors it denotes an adjoint spinor. Kähler manifolds are Hermitian manifolds that admit a two-form called a Kähler form
that is closed . A property of these manifolds is that their metric can be written in terms of the derivatives of a scalar function , where the is known as the Kähler potential. Here denotes a derivative with respect to . This potential corresponding to a particular metric is not unique and can be changed by the addition of the real part of a holomorphic function in what are known as Kähler transformations
Since this does not change the scalar manifold, supersymmetric actions must be invariant under such transformations.
While in global supersymmetry, fields and the superpotential transform trivially under Kähler transformations, in supergravity they are charged under the Kähler transformations as
where is the Majorana spinor supersymmetry transformation parameter. These transformation rules impose further restrictions on the geometry of the scalar manifold. Since the superpotential transforms by a prefactor, this implies that the scalar manifold must globally admit a consistent line bundle. The fermions meanwhile transform by a complex phase, which implies that the scalar manifold must also admit an associated principal bundle. The nondynamical connection corresponding to this principal bundle is given by
with this satisfying , where is the Kähler form. Here are holomorphic functions associated to the gauge sector, described below. This condition means that the scalar manifold in four-dimensional supergravity must be of a type which can admit a connection whose field strength is equal to the Kähler form. Such manifolds are known as Kähler–Hodge manifolds. In terms of characteristic classes, this condition translates to the requirement that where is the first Chern class of the line bundle, while is the cohomology class of the Kähler form.
An implication of the presence of an associated principal bundle on the Kähler–Hodge manifold is that its field strength must be quantized on any topologically non-trivial two-sphere of the scalar manifold, analogous to the Dirac quantization condition for magnetic monopoles. This arises due to the cocycle condition, which is the consistency of the connection across different coordinate patches. This can have various implications for the resulting physics, such as on an scalar manifold, it results in the quantization of Newton's constant.
Global symmetries of ungauged supergravity
Global symmetries in ungauged supergravity fall roughly into three classes; they are subgroups of the scalar manifold isometry group, they are rotations among the gauge fields, or they are the R-symmetry group. The exact global symmetry group depends on the details of the theory, such as the particular superpotential and gauge kinetic function, which provide additional constraints on the symmetry group.
The global symmetry group of a supergravity with abelian vector multiplets and chiral multiplets must be a subgroup of . Here is the isometry group of the scalar manifold, is the set of symmetries acting only on the vector fields, and is the R-symmetry group, with this surviving as a global symmetry only in theories with a vanishing superpotential. When the gauge kinetic matrix is a function of scalars, then the isometry group decomposes into , where the first group acts only on the scalars leaving the vectors unchanged, while the second simultaneously transforms both the scalars and vectors. These simultaneous transformations are not conventional symmetries of the action, rather they are duality transformations that leave the equations of motion and Bianchi identity unchanged, similar to the Montonen–Olive duality.
Global symmetries acting on scalars can only be subgroups of the isometry group of the scalar manifold since the transformations must preserves the scalar metric. Infinitesimal isometry transformations are described by Killing vectors , which are vectors satisfying the Killing equation , where is the Lie derivative along the direction of the Killing vector. They act on the scalars as and are the generators for the isometry algebra, satisfying the structure equation
Since the scalar manifold is a complex manifold, Killing vectors corresponding to symmetries of this manifold must also preserve the complex structure , which implies that they must be holomorphic . Therefore, the gauge group must be a subgroup of the group formed by holomorphic Killing vectors, not merely a subgroup of the isometry group. For Kähler manifolds, this condition additionally implies that there exists a set of holomorphic functions known as Killing prepotentials which satisfy , where is the interior product. The Killing prepotentials can be explicitly written in terms of the Kähler potential
where the holomorphic functions are the Kähler transformations that undo the isometry transformation, defined by
The prepotential must also satisfy a consistency condition known as the equivariance condition
where are the structure constants of the gauge algebra.
An additional restriction on global symmetries of scalars is that the superpotential must be invariant up to the same Kähler transformation that leaves the Kähler potential invariant, which imposes the condition that the only admissible superpotentials are ones satisfying
Global symmetries involving scalars present in the gauge kinetic matrix still act on the scalar fields as isometry transformations, but now these transformations change the gauge kinetic matrix. To leave the theory invariant under a scalar isometry transformation requires a compensating transformation on the vectors. These vector transformations can be expressed as transformations on the electric field strength tensors and their dual magnetic counterpart defined from the equation of motion
Writing the field strengths and dual field strengths in a single vector allows the most general transformations to be written as where the generators of these transformation are given by
Demanding that the equations of motion and Bianchi identities are unchanged restricts the transformations to be a subgroup of the symplectic group . The exact generators depend on the particular gauge kinetic matrix, with them
fixing the coefficients determining . Transformations involving , are non-perturbative symmetries that do not leave the action invariant since they map the electric field strength into the magnetic field strength. Rather, these are duality transformations that are only symmetries at the level of the equations of motion, related to the electromagnetic duality. Meanwhile, transformations with are known as generalized Peccei–Quinn shifts and they only leave the action invariant up to total derivatives. Global symmetries involving only vectors are transformations that map the field strength tensor into itself and generally belong to .
Gauge symmetry
In an ungauged supergravity, gauge symmetry only consists of abelian transformations of the gauge fields , with no other fields being gauged.
Meanwhile, gauged supergravity gauges some of the global symmetries of the ungauged theory. Since the global symmetries are strongly limited by the details of the theory present, such as the scalar manifold, the scalar potential, and the gauge kinetic matrix, the available gauge groups are likewise limited.
Gauged supergravity is invariant under the gauge transformations with gauge parameter given by
Here are the generators of the gauged algebra while are defined as the compensating Kähler transformations needed to restore the Kähler potential to its original form after performing scalar field isometry transformations, with their imaginary components fixed by the equivariance condition. Whenever a subgroup is gauged, as occurs when R-symmetry is gauged, this does not fix , with these terms then referred to as Fayet–Iliopoulos terms.
Covariant derivatives
Supergravity has a number of distinct symmetries, all of which require their own covariant derivatives. The standard Lorentz covariant derivative on curved spacetime is denoted by , with this being trivial for scalar fields, while for fermionic fields it can be written using the spin connection as
Scalars transform nontrivially only under scalar coordinate transformations and gauge transformations, so their covariant derivative is given by
where are the holomorphic Killing vectors corresponding to the gauged isometry subgroup of the scalar manifold. A hat above a derivative indicates that it is covariant with respect to gauge transformations. Meanwhile, the superpotential only transforms nontrivially under Kähler transformations and so has a covariant derivative given by
where is a derivative with respect to .
The various covariant derivatives associated to the fermions depend upon which symmetries the fermions are charged under. The gravitino transforms under both Lorentz and Kähler transformation, while the gaugino additionally also transforms under gauge transformations. The chiralino transforms under all these as well as transforming as a vector under scalar field redefinitions. Therefore, their covariant derivatives are given by
Here is the Christoffel symbol of the scalar manifold, while are the structure constants of the Lie algebra associated to the gauge group. Lastly, is the connection on the scalar manifold, with its explicit form given in terms of the Kähler potential described previously.
R-symmetry
R-symmetry of superalgebras is a global symmetry acting only on fermions, transforming them by a phase
This is identical to the way that a constant Kähler transformation acts on fermions, differing from such transformations only in that it does not additionally transform the superpotential. Since Kähler transformations are necessarily symmetries of supergravity, R-symmetry is only a symmetry of supergravity when these two coincide, which only occurs for a vanishing superpotential.
Whenever R-symmetry is a global symmetry of the ungauged theory, it can be gauged to construct a gauged supergravity, which does not necessarily require gauging any chiral scalars. The simplest example of such a supergravity is Freedman's gauged supergravity which only has a single vector used to gauge R-symmetry and whose bosonic action is equivalent to an Einstein–Maxwell–de Sitter theory.
4D N = 1 supergravity Lagrangian
The Lagrangian for 4D supergravity with an arbitrary number of chiral and vector supermultiplets can be split up as
Besides being invariant under local supersymmetry transformations, this Lagrangian also is Lorentz invariant, gauge invariant, and Kähler transformation invariant, with covariant derivatives being covariant under these. The three main functions determining the structure of the Lagrangian are the superpotential, the Kähler potential, and the gauge kinetic matrix.
Kinetic and theta terms
The first term in the Lagrangian consists of all the kinetic terms of the fields
The first line is the kinetic action for the supergravity multiplet, made up of the Einstein–Hilbert action and the covariantized Rarita–Schwinger action; this line is the covariant generalization of the pure supergravity action. The formalism used for describing gravity is the vielbein formalism, where is the vielbein while is the spin-connection. Additionally, and is the four-dimensional Planck mass.
The second line consists of the kinetic terms for the chiral multiplets, with its overall form determined by the scalar manifold metric which itself is fully fixed by the Kähler potential . The third line has the kinetic terms for the gauge multiplets, with their behaviour fixed by the real part of the gauge kinetic matrix. The holomorphic gauge kinetic matrix must have a positive definite real part to have kinetic terms with the correct sign. The slash on the covariant derivatives corresponds to the Feynman slash notation , while are the field strengths of the gauge fields .
The gauge sector also introduces a theta-like term
with this being a total derivative whenever the imaginary part of the gauge kinetic matrix is a constant, in which case it does not contribute to the classical equations of motion.
Mass and interaction terms
The supergravity action has a set of mass-like bilinear terms for its fermions given by
The D-terms are defined as
where are the holomorphic Killing prepotentials and is the holomorphic superpotential. The first line in the Lagrangian is the mass-like term for the gravitino while the remaining two lines are the mass terms for the chiralini and gluini along with bilinear mixing terms for these. These terms determine the masses of the fermions since evaluating the Lagrangian in a vacuum state with constant scalar fields reduces the Lagrangian to a set of fermion bilinears with numerical prefactors. This can be written as a matrix, with the eigenvalues of this mass matrix being the masses of the fermions in the mass basis. The mass eigenstates are in general linear combinations of the chiralini and gaugini fermions.
The next term in the Lagrangian is the supergravity generalization of a similar term found in the corresponding globally supersymmetric action that describes mixing between the gauge boson, a chiralino, and the gaugino. In the supergravity Lagrangian it is given by
Supercurrent terms
The supercurrent terms describe the coupling of the gravitino to generalizations of the chiral and gauge supercurrents from global supersymmetry as
where
These are the supercurrents of the chiral sector and of the gauge sector modified appropriately to be covariant under the symmetries of the supergravity action. They provide additional bilinear terms between the gravitino and the other fermions that need to be accounted for when going into the mass basis.
The presence of terms coupling the gravitino to the supercurrents of the global theory is a generic feature of supergravity theories since the gravitino acts as the gauge field for local supersymmetry. This is analogous to the case of gauge theories more generally, where gauge fields couple to the current associated to the symmetry that has been gauged. For example, quantum electrodynamics consists of the Maxwell action and the Dirac action, together with a coupling between the photon and the current , with this usually being absorbed into the definition of the fermion covariant derivative.
Scalar potential
The potential term in the Lagrangian describes the scalar potential as
where the first term is known as the F-term, and is a generalization of the potential arising from the chiral multiplets in global supersymmetry, together with a new negative gravitational contribution proportional to . The second term is called the D-term and is also found in a similar form in global supersymmetry, with it arising from the gauge sector.
The Kähler potential and the superpotential are not independent in supergravity since Kähler transformations allow for the shifting of terms between them. The two functions can instead be packaged into an invariant function known as the Kähler invariant function
The Lagrangian can be written in terms of this function as
Four-fermion terms
Finally, there are the four-fermion interaction terms. These are given by
Here is the scalar manifold Riemann tensor, while is the supergravity four-gravitino interaction term
that arises in the second-order action of pure supergravity after the torsion tensor has been substituted into the first-order action.
Properties
Supersymmetry transformation rules
The supersymmetry transformation rules, up to three-fermion terms which are unimportant for most applications, are given by
where
are known as fermionic shifts. It is a general feature of supergravity theories that fermionic shifts fix the form of the potential. In this case they can be used to express the potential as
showing that the fermionic shifts from the matter fields gives a positive-definite contribution, while the gravitino gives a negative definite contribution.
Spontaneous symmetry breaking
A vacuum state used in many applications of supergravity is that of a maximally symmetric spacetime with no fermionic condensate. The case when fermionic condensates are present can be dealt with similarly by instead considering the effective field theory below the condensation scale where the condensate is now described by the presence of another scalar field. There are three types of maximally symmetric spacetimes, those being de Sitter, Minkowski, and anti-de Sitter spacetimes, with these distinguished by the sign of the cosmological constant, which in supergravity at the classical level is equivalent to the sign of the scalar potential.
Supersymmetry is preserved if all supersymmetric variations of fermionic fields vanish in the vacuum state. Since the maximally symmetric spacetime under consideration has a constant scalar field and a vanishing gauge field, the variation of the chiralini and gluini imply that . This is equivalently to the condition that . From the form of the scalar potential it follows that one can only have a supersymmetric vacuum if . Additionally, supersymmetric Minkowski spacetime occurs if and only if the superpotential also vanishes . However, having a Minkowski or an anti-de Sitter solution does not necessarily imply that the vacuum is supersymmetric. An important feature of supersymmetic solutions in anti-de Sitter spacetime is that they satisfy the Breitenlohner–Freedman bound and are therefore stable with respect to fluctuations of the scalar fields, a feature that is present in other supergravity theories as well.
Supergravity provides a useful mechanism for spontaneous symmetry breaking of supersymmetry known as gravity mediation. This setup has a hidden and an observable sector that have no renormalizable couplings between them, meaning that they fully decouple from each other in the global supersymmetry limit. In this scenario, supersymmetry breaking occurs in the hidden sector, with this transmitted to the observable sector only through nonrenormalizable terms, resulting in soft supersymmetry breaking in the visible sector, meaning that no quadratic divergences are introduced. One of the earliest and simplest models of gravity mediation is the Polonyi model. Other notable spontaneous symmetry breaking mechanism are anomaly mediation and gauge mediation, in which the tree-level soft terms generated from gravity mediation are themselves subdominant.
Super-Higgs mechanism
The supercurrent Lagrangian terms consists in part of bilinear fermion terms mixing the gravitino with the other fermions. These terms can be expressed as
where is the supergravity generalization of the global supersymmetry goldstino field
This field transforms under supersymmetry transformations as , where is the positive part of the scalar potential. When supersymmetry is spontaneously broken , then one can always choose a gauge where , in which case the terms mixing the gravitino with the other fermions drops out. The only remaining fermion bilinear term involving the gravitino is the quadratic gravitino term in . When the final spacetime is Minkowski spacetime, this bilinear term corresponds to a mass for the gravitino with a value of
An implication of this procedure when calculating the mass of the remaining fermions is that the gauge fixing transformation for the goldstino leads to additional shift contributions to the mass matrix for the chiral and gauge fermions, which have to be included.
Mass sum rules
The supertrace sum of the squares of the mass matrix eigenvalues gives valuable information about the mass spectra of particles in supergravity. The general formula is most compactly written in the superspace formalism, but in the special case of a vanishing cosmological constant, a trivial gauge kinetic matrix , and chiral multiplets, it is given by
which is the supergravity generalization of the corresponding result in global supersymmetry. One important implication is that generically scalars have masses of order of the gravitino mass while fermionic masses can remain small.
No-scale models
No-scale models are models with a vanishing F-term, achieved by picking a Kähler potential and superpotential such that
When D-terms for gauge multiplets are ignored, this gives rise to the vanishing of the classical potential, which is said to have flat directions for all values of the scalar field. Additionally, supersymmetry is formally broken, indicated by a non-vanishing but undetermined mass of the gravitino. When moving beyond the classical level, quantum corrections come in to break this degeneracy, fixing the mass of the gravitino. The tree-level flat directions are useful in pheonomenological applications of supergravity in cosmology where even after lifting the flat directions, the slope is usually relatively small, a feature useful for building inflationary potentials. No-scale models also commonly occur in string theory compactifications.
Quantum effects
Quantizing supergravity introduces additional subtleties. In particular, for supergravity to be consistent as a quantum theory, new constraints come in such as anomaly cancellation conditions and black hole charge quantization. Quantum effects can also play an important role in many scenarios where they can contribute dominant effects, such as when quantum contributions lift flat directions. The nonrenormalizability of four-dimensional supergravity also implies that it should be seen as an effective field theory of some UV theory.
Quantum gravity is expected to have no exact global symmetries, which forbids constant Fayet–Iliopoulos terms as these can only arise if there are exact unbroken global symmetries. This is seen in string theory compactifications, which can at most produce field dependent Fayet–Iliopoulos terms associated to Stueckelberg masses for gauged symmetries.
Related theories
A globally supersymmetric 4D theory can be acquired from its supergravity generalization through the decoupling of gravity by rescaling the gravitino and taking the Planck mass to infinity . The pure supergravity theory is meanwhile acquired by having no chiral or gauge multiplets. Additionally, a more general version of 4D supergravity exists that also includes Chern–Simon terms.
Unlike in global supersymmetry, where all extended supersymmetry models can be constructed as special cases of the theory, extended supergravity models are not merely special cases of the theory. For example, in supergravity the relevant scalar manifold must be a quaternionic Kähler manifold. But since these manifolds are not themselves Kähler manifolds, they cannot occur as special cases of the supergravity scalar manifold.
Four-dimensional supergravity plays a significant role in Beyond the Standard Model physics, being especially relevant in string theory, where it is the resulting effective theory in many compactifications. For example, since compactification on a 6-dimensional Calabi–Yau manifold breaks 3/4ths of the initial supersymmetry, compactification of heterotic strings on such manifolds gives an supergravity, while the compactification of type II string theories gives an supergravity. But if the type II theories are instead compactified on a Calabi–Yau orientifold, which breaks even more of the supersymmetry, the result is also an supergravity. Similarly, compactification of M-theory on a manifold also results in an supergravity. In all these theories, the particular properties of the resulting supergravity theory such as the Kähler potential and the superpotential are fixed by the geometry of the compact manifold.
Notes
References
Supersymmetric quantum field theory
Theories of gravity | 4D N = 1 supergravity | [
"Physics"
] | 6,713 | [
"Supersymmetric quantum field theory",
"Theoretical physics",
"Theories of gravity",
"Supersymmetry",
"Symmetry"
] |
76,995,422 | https://en.wikipedia.org/wiki/AI%20Seoul%20Summit | The 2024 AI Seoul Summit was co-hosted by the South Korean and British governments. The Seoul Declaration was adopted to address artificial intelligence technology and related challenges and opportunities.
Background
The AI Seoul Summit is the second such meeting following the AI Safety Summit held in the United Kingdom in November 2023. In the Bletchley Declaration, the participating countries agreed to prioritize identifying AI safety risks of shared concern, a shared concern, but at the Seoul Summit, the leaders also recognized the importance of AI.
Notable attendees
The summit was attended by the leaders of Group of Seven countries, including the United States, Canada, France, and Germany, South Korea, Singapore and Australia, representatives of the United Nations, the Organisation for Economic Co-operation and Development, and the European Union.
Also in attendance were representatives of global companies such as Tesla CEO Elon Musk, Samsung Electronics Chairman Lee Jae-yong, ChatGPT maker OpenAI, Google, Microsoft, Meta, and South Korea's top portal operator Naver.
AI safety research center
Minister of Science, Lee Jong-ho said that South Korea was planning to open an AI Safety Institute in 2024. He also expressed his intention to strengthen cooperation for the development of international standards.
Outcomes
Seoul Declaration for Safe, Innovative and Inclusive AI
The Seoul Declaration was adopted at the summit by leaders representing the EU, the USA, the UK, Australia, Canada, Germany, France, Italy, Japan, South Korea, and Singapore. The declaration is a commitment to foster international cooperation to help develop AI governance frameworks that are interoperable between countries, partly by integrating the Hiroshima Process International Code of Conduct for Organizations Developing Advanced AI Systems. It advocates for the development of human-centric AI in collaboration with the private sector, academia, and civil society.
Seoul Ministerial Statement for advancing AI safety
At the ministerial meeting of the summit, the Seoul Ministerial Statement, a joint statement calling for the improvement of the safety, innovation, and inclusivity of AI technologies, was adopted by ministers from Australia, Canada, Chile, France, Germany, India, Indonesia, Israel, Italy, Japan, Kenya, Mexico, the Netherlands, Nigeria, New Zealand, the Philippines, South Korea, Rwanda, Saudi Arabia, Singapore, Spain, Switzerland, Turkey, Ukraine, the United Arab Emirates, the UK, and the USA, as well as an EU representative. It aims to develop low-power chips as the AI industry rapidly expands and massive consumption is expected.
See also
Artificial Intelligence
Foreign relations of South Korea
References
Artificial intelligence conferences
2024 conferences
May 2024 events in South Korea
Presidency of Yoon Suk Yeol
Regulation of artificial intelligence | AI Seoul Summit | [
"Technology"
] | 536 | [
"Computing and society",
"Regulation of artificial intelligence"
] |
76,995,479 | https://en.wikipedia.org/wiki/PKS%200537-286 | PKS 0537-286 (referred to QSO 0537-286), also known as QSO B0537-286, is a quasar located in the constellation Columba. With a redshift of 3.104, the object is located 11.4 billion light years away and belongs to the flat spectrum radio quasar blazar subclass (FSQR). It is one of the most luminous known high-redshift quasars.
Observation history
First detected at radio frequencies in 1975, PKS 0537-286 was observed at X-rays by the Einstein observatory. It was later studied by ASCA, ROSAT, XMM and subsequently Swift. These observations showed PKS 0537-286 as extremely luminous quasar ( Lx=1047 erg s−1 in the 0.1-2 keV range) with a particularly hard spectrum (r = 1 measured by Swift/BAT), which in the γ-ray band, it shows an energy flux of (1.44 ± 0.006) × 10−11 erg cm−2 s−1 in the fourth catalogue of Fermi-LAT active galactic nuclei. A weak iron K emission line and reflection features is also found in PKS 0537-286. Moreover, Sowards-Emmerd et al. (2004) identified the quasar as probable counterpart of the EGRET source 3EG J0531-2940.
Characteristics
PKS 0537-286 is the brightest blazar beyond z = 3.0. It shows characteristic properties of blazars, such as (rapid variability, strong polarization and high brightness) which are widely attributed to a powerful relativistic jet oriented close to the line of sight.
Moreover, in several occasions, γ-ray flares were observed when the daily flux was above 10−6 photon cm−2 s−1. This makes PKS 0537-286 the most distant γ-ray flaring blazar. The broad-band emission from PKS 0537-286 was successfully modelled within a one-zone synchrotron and external inverse Compton scenario where the excess in optical and ultraviolet bands was interpreted as emission from bright thermal accretion disc. Moreover, PKS 0537-286 shows an emission redshift of 3.11, a prominent absorption system at a redshift of 2.976, and a strong discontinuity at the Lyman-continuum edge in the absorption system.
Supermassive black hole
The central supermassive black hole in PKS 0537-286 is one of the largest and heaviest black holes known, with a high accretion rate. Based on a study published in 2010, the black hole contains a solar mass of 2 x 109.
References
Columba (constellation)
Quasars
Blazars
Active galaxies
Supermassive black holes | PKS 0537-286 | [
"Physics",
"Astronomy"
] | 600 | [
"Black holes",
"Columba (constellation)",
"Unsolved problems in physics",
"Supermassive black holes",
"Constellations"
] |
76,995,631 | https://en.wikipedia.org/wiki/TensorFloat-32 | TensorFloat-32 or TF32 is a numeric floating point format designed for Tensor Core running on certain Nvidia GPUs.
Format
The binary format is:
1 sign bit
8 exponent bits
10 fraction bits (also called mantissa, or precision bits)
The total 19 bits fits within a double word (32 bits), and while it lacks precision compared with a normal 32 bit IEEE 754 floating point number, provides much faster computation, up to 8 times on a A100 (compared to a V100 using FP32).
See also
IEEE 754
References
External links
Computer arithmetic
IEEE standards
Floating point types
Binary arithmetic | TensorFloat-32 | [
"Mathematics",
"Technology"
] | 132 | [
"Computer standards",
"Computer arithmetic",
"Arithmetic",
"Binary arithmetic",
"IEEE standards"
] |
76,995,944 | https://en.wikipedia.org/wiki/Realme%20GT%206T | The Realme GT 6T is an upper mid-range smartphone developed by Realme as a part of its Realme GT lineup. It was announced on May 22, 2024 and launched on May 29, 2024.
On the 11th of April 2024 in China, Realme introduced the Realme GT Neo 6 SE, which shares similar specifications with the Realme GT 6T, but features a different charging power.
Features
Display
The GT 6T and GT Neo 6 SE feature a 6.78-inch 1.5K LTPO AMOLED display, which supports a 120Hz refresh rate and offers up to 6000 nits peak brightness. It is protected by Corning Gorilla Glass Victus 2.
Performance
GT 6T and GT Neo6 SE are the first smartphones powered by the Qualcomm Snapdragon 7+ Gen 3 chipset. GT 6T offers configurations up to 12 GB of RAM and 512 GB of storage, supplemented by a cooling system to manage thermal performance.
Camera
The devices include a dual rear camera setup with a 50MP primary sensor and an 8MP ultra-wide sensor, along with a 32MP front camera. The main rear camera is equipped with Optical Image Stabilization (OIS).
Battery and charging
They house a 5500 mAh battery supporting 120 W SuperVOOC fast charging in GT 6T, claiming significant charge within minutes, and 100 W SuperVOOC fast charging in GT Neo6 SE.
Software
The phones run on Realme UI 5 based on Android 14, with a promise of three years of major updates and four years of security updates.
Critical response
Business Standard praised the phone's smooth performance and battery life. Fonearena praised the phone and called it a performance champ but gave average ratings to its camera. Digit gave it 7.2 out of 10 and praised its performance but criticized its design. 91mobiles gave it 8 out of 10 and praised its display and fast performance.
References
GT 6T
Android (operating system) devices
Mobile phones introduced in 2024
Mobile phones with 4K video recording
Mobile phones with multiple rear cameras
Phablets | Realme GT 6T | [
"Technology"
] | 429 | [
"Crossover devices",
"Phablets"
] |
76,997,285 | https://en.wikipedia.org/wiki/Acetamidine%20hydrochloride | Acetamidine hydrochloride is an organic compound with the formula , used in the synthesis of many nitrogen-bearing compounds. It is the hydrochloride of acetamidine, one of the simplest amidines.
Properties
Acetamidine hydrochloride is a hygroscopic solid which forms colourless monoclinic crystals. It is soluble in water and alcohol.
It releases ammonium chloride upon heating. Dry acetamidine hydrochloride releases acetonitrile, while in aqueous solution, it instead undergoes hydrolysis to acetic acid and ammonia.
As free base amidines are strong Lewis bases, acetamidine hydrochloride is a weak Lewis acid. Treatment with strong base gives free base acetamidine:
Synthesis
Acetamidine hydrochloride is synthesised in a two-step process that begins with a solution of acetonitrile in ethanol at close to . First, the mixture is treated with anhydrous hydrogen chloride in a Pinner reaction, producing crystals of acetimido ethyl ether hydrochloride:
The imino ether salt is then treated with an excess of ammonia in dry ethanol, converting the ether to the amidine:
All reagents must be thoroughly dried using a strong desiccant such as phosphorus pentoxide, as the intermediate imido ether is susceptible to hydrolysis, yielding ammonium chloride and ethyl formate. Layers of ammonium chloride can form on the imido ether salt, limiting the formation of amidine.
Applications
As a source of amidine, acetamidine hydrochloride is a precursor to the industrial and laboratory synthesis of many nitrogen compounds. It reacts with β-dicarbonyls to produce substituted pyrimidines, with acetaldehydes to form substituted imidazoles, and with imidates to form substituted triazines.
In particular, its reaction with a dicarbonyl intermediate is an early step in the synthesis of thyamine (vitamin B1) and many of its derivatives.
References
Hydrochlorides
Amidines | Acetamidine hydrochloride | [
"Chemistry"
] | 434 | [
"Bases (chemistry)",
"Amidines",
"Functional groups"
] |
76,997,330 | https://en.wikipedia.org/wiki/Coerulescine | Coerulescine is an oxindole alkaloid found in the plant Phalaris coerulescens.
It is a member of the spiroindolone class. Elacomine and horsfiline have similar chemical structures.
References
Phenol ethers
Lactams
Oxindoles
Pyrrolidine alkaloids
Spiro compounds | Coerulescine | [
"Chemistry"
] | 75 | [
"Organic compounds",
"Alkaloids by chemical classification",
"Pyrrolidine alkaloids",
"Spiro compounds"
] |
76,998,123 | https://en.wikipedia.org/wiki/Nion%20%28company%29 | Nion was a manufacturer of scanning transmission electron microscopes (STEMs) based in Kirkland, Washington State, USA.
History
Nion Co. was founded in 1997 in Washington State, USA, by Ondrej Krivanek and Niklas Dellby, with a mission to design and build advanced instruments for electron microscopy. Prior to founding Nion, Krivanek and Dellby built a working proof-of-principle aberration corrector for a STEM, in Cambridge UK. Following this success, Philip Batson of IBM TJ Watson Research Center asked them to build an aberration corrector for his STEM. Krivanek was a research professor at University of Washington at the time, and he and Dellby decided to start Nion Co. and build a redesigned corrector. The new corrector was delivered to IBM in June 2020, and demonstrated direct sub-Å resolution. Nion went on to supply the scientific community with correctors for 100 and 300 kV dedicated STEMs made by Vacuum Generators. Nion's 2004 Science article demonstrated 0.78 Å resolution and led to wide acceptance of aberration correction as the best way to achieve high spatial resolution in electron microscopy.
It soon became clear that a new, higher stability electron microscope was needed, built from the ground up so that resolutions of 0.5 Ångstroms and below could be reached. Nion developed such an instrument as its next project: a 100 kV aberration corrected, high-stability electron microscope called UltraSTEM, with resolution capability well below one Angstrom. The first deliveries of this instrument took place in 2008, to Cornell University and the SuperSTEM Daresbury Laboratory. A 200 kV version of this microscope was delivered to the Orsay STEM laboratory near Paris in 2010 and many other labs since. It is able to reach 0.5 Å resolution.
Nion went on to develop a monochromated STEM, with the first delivery to Arizona State University in 2013 and subsequent deliveries to Rutgers University, Daresbury SuperSTEM, and many other laboratories in the USA, Canada, Europe and China. In 2014, the ASU and Rutgers monochromatic STEMs showed that phonons could be detected with high spatial resolution in an electron microscope by ultra-high energy resolution electron energy loss spectroscopy (EELS). In 2018, Nion introduced a new EELS spectrometer, which improved the EELS resolution to 3 meV, and allowed the vibrations of single atoms to be studied.
Other innovations introduced by Nion and the ongoing operation under the Bruker umbrella include X-ray spectroscopy with single-atom sensitivity, imaging samples in a contamination-free ultra-high vacuum (UHV) environment, atomic resolution secondary electron imaging (SEI) of surfaces of samples held in UHV, and stable imaging at temperatures <10 K.
Awards
In 2020, co-founder of Nion, Ondrej Krivanek, shared the Kavli Prize for Nanoscience for work creating the first aberration-corrected scanning transmission electron microscope with resolution below one ångstrom (0.1 nanometers).
Acquisition
In January 2024, Nion was acquired by Bruker, which moved Bruker into the manufacture of electron microscopes.
References
Crystallography
Electron microscopy
Electron beam
Materials science | Nion (company) | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 671 | [
"Electron",
"Electron microscopy",
"Applied and interdisciplinary physics",
"Electron beam",
"Materials science",
"Crystallography",
"Condensed matter physics",
"nan",
"Microscopy"
] |
76,998,238 | https://en.wikipedia.org/wiki/Consent%20or%20pay | Consent-or-pay, also called pay-or-okay, is a compliance tactic used by certain companies, most notably Meta, to drive up the rates at which users consent to data processing under the European Union's General Data Protection Regulation (GDPR). It consists of presenting the user with a tracking consent notice, but only allowing a binary choice: either the user consents to the data processing, or they are required to pay to use the service, which is otherwise free to use if data processing is consented to. The tactic has been criticised by privacy advocates and non-governmental organisations such as NOYB and Wikimedia Europe, which claim that it is illegal under the GDPR. On 17 April 2024, the European Data Protection Board released a non-binding opinion stating that in most cases, consent-or-pay models do not constitute valid consent within the meaning of the GDPR.
Background
Under the GDPR, the processing of a natural person's personal data is only allowed under six lawful bases: consent, contractual necessity, legal obligation under EU or member state law, public interest, protection of vital interest of an individual, and the processor's legitimate interest.
When the GDPR first came into force in 2018, Meta justified its processing of personal data by claiming that its terms of use constitute a contract under which the user consented to the processing of personal data.
However, this was challenged by Max Schrems, an Austrian privacy activist, who successfully argued that contractual necessity was not a valid basis of data processing when it comes to personalised advertising.
In response to this ruling, Meta changed its lawful basis for personal data processing from contractual necessity to legitimate interest, which was also found not to be a valid basis.
Meta then changed its lawful basis to consent, but chose to implement it in a way where users who consented to personalised advertising could use the service for free, while those who did not were required to pay a monthly subscription fee to continue using the service.
Critics of this consent model have called it "pay-or-okay", claiming that the monthly fee is disproportional and that users are not able to withdraw their consent to tracking as easily as it is given, which the GDPR requires. Massimiliano Gelmi, a data protection lawyer at NOYB, has stated that "The law is clear, withdrawing consent must be as easy as giving it in the first place. It is painfully obvious that paying €251,88 per year to withdraw consent is not as easy as clicking an 'Okay' button to accept the tracking."
On 17 April 2024, the European Data Protection Board released a non-binding opinion stating that in most cases, consent-or-pay models do not constitute valid consent within the meaning of the GDPR.
European Commission investigation
On 1 July 2024, the European Commission announced that it had opened an investigation against Meta under the provisions of the Digital Markets Act (DMA), with the preliminary findings claiming that Meta's approach was not in compliance with the DMA, an assertion that Meta has disputed.
Other users
Although Meta has faced most of the scrutiny and criticism regarding the use of consent-or-pay, other companies have also utilised the tactic. The Austrian Data Protection Authority (Datenschutzbehörde) has found that Der Standard, a German-language newspaper, has acted unlawfully by using consent-or-pay on its site, while others, including Der Spiegel, Die Zeit, Heise, the Frankfurter Allgemeine Zeitung, the Kronen Zeitung, and T-Online, have been accused of doing the same.
References
Information privacy
Data protection | Consent or pay | [
"Engineering"
] | 758 | [
"Cybersecurity engineering",
"Information privacy"
] |
76,998,684 | https://en.wikipedia.org/wiki/5G%20Broadcast | 5G Broadcast (5GB), officially known as LTE-based 5G Terrestrial Broadcast, is a system for the distribution of television and other broadcast media content via terrestrial radio broadcast networks based on downlink-only LTE technology.
5G Broadcast focuses mainly on mobile use cases like smartphones and in-car radio. It does not require the use of a SIM card or cellular subscription, but only a device like a smartphone capable of receiving 5G Broadcast signals, thus bypassing telecommunication and cellular operators entirely. A stated advantage has been the ability to reduce load off mobile networks during large live broadcasts, and not requiring an internet connection. In a broadcast mode, data can be sent to multiple receivers at once (point-to-multipoint) as opposed to point-to-point.
The technology has been tested in numerous countries for a number of years, and has been tipped in Europe as the potential future for digital terrestrial television, which currently are mainly based on the DVB-T2 standard. Public broadcasters of France, Italy, Germany, the Netherlands, Ireland and Austria have signed a cooperation pact in 2023 and have stated the use of the UHF 470–694 MHz frequency band to be used for 5G Broadcast.
In September 2023 the specs of the standard was updated and published by the 3GPP organisation. It started being tested by some low-power television stations in the USA and also in Spain by UHD. In Germany, 5G Broadcast has been trialed and in May 2024 another pilot project is set to begin in the city of Halle. It is separate from the ATSC 3.0 transmission standard which is also being rolled out. In France, a trial is operated by TDF since the Paris 2024 Olympic games.
Comparison with ATSC 3.0
In comparison with ATSC 3.0, the "NextGenTV" IP-based broadcasting standard being introduced in the USA, 5G Broadcast has been criticised for lower bandwidth efficiency, and the lack of a future-proofing "bootstrap" signal to enable the introduction of new physical-level modulation profiles. However, 5G Broadcast was seen as having the advantage in most other aspects of performance.
References
Digital television
Mobile television
3GPP standards
5G (telecommunication)
Mobile telecommunications | 5G Broadcast | [
"Technology"
] | 464 | [
"Mobile telecommunications",
"Mobile television"
] |
76,998,906 | https://en.wikipedia.org/wiki/Beijing%20Institute%20of%20Tracking%20and%20Telemetry%20Technology | The Beijing Institute of Tracking and Telecommunications Technology () aka BITTT is a research institution of the Aerospace Force of the People's Liberation Army. The head office is located in the Beijing Space City in the north of Haidian district. The head of the institute, Dong Guangliang (董光亮), is also the Technical Director of the Control and Communication Systems of the Manned Space Program of the PRC since September 2015. The BITTT is an observer member of the Consultative Committee for Space Data Systems.
History
The "Research Institute for Orbit Tracking and Communication Technology" was founded in May 1965 in connection with Project 651, the program to build and launch a Chinese satellite that began in January 1965.As part of this project, the institute was initially responsible for planning the radar facilities at the Jiuquan Launch site, the facilities of the ground stations of the Chinese Space Control Network, and its headquarters, which was located in Weinan at the time. After China's first satellite, Dongfanghong 1, was successfully launched into space on 24 April 1970, the institute took on a leading role in the further expansion of the space control network, not only as a technical planning office, but also as an intermediary between the individual departments.
As of the 2020s, BITTT has established itself as the main systems design and general contracting technical unit in the field of aerospace measurement, control and communication in China, the chief designer unit of the two major systems of measurement, control and communication for the landing site and for emergency rescue of China's manned space program. It is an affiliated unit of the Spacecraft Measurement and Control Committee of the Chinese Society of Astronautics, and a Class A design unit of the communication industry approved by the state.
As a general contractor, BITTT was also responsible for the design and construction of the Inmarsat Beijing ground station, for the computer systems for the Beijing ground station of the Sinosat communication satellites and for the computer systems of the satellite control centers of Nigeria and Venezuela
Academics
BITTT has also been a teaching institution since 1985, and has had title-granting authority since 2008. Degree of "Postgraduate Specialist" (专业硕士), roughly at master level, are granted in the following four programs:
Communication and Information Systems Engineering (通信与信息系统)
Navigation, steering and control (导航、制导与控制)
Signal and Data Processing (信号与信息处理)
Applied computer science (计算机应用技术)
In a peculiarity of its status as a military unit, there are rules requiring minimum height (1.62m for men and 1.58 m for women), no short- or long-sightedness, or color blindness.
The institute has 500 scientific and technological personnel, including more than 350 with master's degrees or above, and more than 60 with doctoral degrees or above, and more than 180 senior researchers, senior engineers and equivalent technical positions. It is composed of more than 10 laboratories. It has an above-average production of patents and awards. The institute has also a quite broad set of exchange and cooperation projects with more than 20 countries.
Projects involved
Beidou Satellite Navigation System
Shenzhou program
China Moon Program
China Mars Program
References
People's Liberation Army
Military units and formations established in the 1960s
Space exploration
Telemetry
Tracking and Data Relay Satellite
Chinese scientific instrument makers | Beijing Institute of Tracking and Telemetry Technology | [
"Astronomy"
] | 687 | [
"Space exploration",
"Outer space"
] |
76,999,108 | https://en.wikipedia.org/wiki/Gliese%2012 | Gliese 12 (GJ 12) is a red dwarf star located away in the constellation Pisces. It has about 24% the mass and 26% the radius of the Sun, and a temperature of about . It is an inactive star and hosts one known exoplanet.
Planetary system
The transiting exoplanet Gliese 12 b was discovered by TESS, and two independent studies confirming it as a planet were published in May 2024. Gliese 12 b is similar in size to Earth and Venus, and completes an orbit around its star every 12.8 days. Its mass is poorly constrained but is known to be less than 4 times that of Earth.
Along with the planets of TRAPPIST-1 and LHS 1140 b, Gliese 12 b is one of the nearest known relatively temperate transiting exoplanets, and so is a promising target for the James Webb Space Telescope to determine whether it has retained an atmosphere. Gliese 12 b orbits slightly closer than the inner edge of its star's habitable zone, with an insolation between those of Earth and Venus. Its equilibrium temperature, assuming an albedo of zero, is ; if it has an atmosphere, the surface temperature would be greater than this.
References
Pisces (constellation)
M-type main-sequence stars
Planetary systems with one confirmed planet
J00154919+1333218
0012
52005579
6251 | Gliese 12 | [
"Astronomy"
] | 298 | [
"Pisces (constellation)",
"Constellations"
] |
76,999,747 | https://en.wikipedia.org/wiki/Kolchin%27s%20problems | Kolchin's problems are a set of unsolved problems in differential algebra, outlined by Ellis Kolchin at the International Congress of Mathematicians in 1966 (Moscow)
Kolchin Catenary Conjecture
The Kolchin Catenary Conjecture is a fundamental open problem in differential algebra related to dimension theory.
Statement
"Let be a differential algebraic variety of dimension
By a long gap chain we mean a chain of irreducible differential subvarieties of ordinal number length ."
Given an irreducible differential variety of dimension and an arbitrary point , does there exist a long gap chain beginning at and ending at ?
The positive answer to this question is called the Kolchin catenary conjecture.
References
Differential algebra
Dimension theory | Kolchin's problems | [
"Mathematics"
] | 147 | [
"Differential algebra",
"Fields of abstract algebra"
] |
77,002,188 | https://en.wikipedia.org/wiki/PKS%200438-436 | PKS 0438-436, also known as PKS J0440-4333, is a quasar located in constellation Caelum. With a high redshift of 2.86, the object is located 11.2 billion light-years from Earth and is classified as a blazar due to its flat-spectrum radio source, (in terms of the flux density as (Fv ~ V−a) with α < 0.5 and its optical polarization.
Characteristics
PKS 0438-436 features the second strongest known synchrotron core, in which three strong absorption lines are superposed on Lo emission, and two of them are at longer wavelengths. PKS 0438-436 is said to be t highly variable, changing from 4.7% to 1.7% with a 150 degree swing in position angle over seven months. However, the quasar has an enormous low-frequency flux density. It is 160 MHz flux density at 7.9 Jy, compared to the most luminous blazars equivalent to 151 MHz luminosity of L151 ≈ 4.5 x 1028 WH z−1 sr−1. This is the very rare object that lies near the high end of the luminosity distribution at both low frequency and high frequency (≥5 GHz).
Moreover, through the study of ROSAT PSPC spectrum, PKS 0438-436 shows an unexpected absorption of ~1 x 10^22^ cm^-2^, assuming it occurs at the source. Only one other high-luminosity quasar (of >~ 50 observed by Einstein) shows significant absorption in its X-ray spectrum. Of the common line-of-sight absorbers, only highly ionized Lyα forest clouds may be able to explain this amount of absorption. This is mainly due to primarily to heavy elements such as Oxygen, Neon, Magnesium, Silicon, Sulfur, raising the possibility of measuring early universe abundances via X-ray absorption in this and like quasars. PKS 0438-436 may be a high-redshift member of a population of quasars which can contribute to the X-ray background above 2 keV, without being detectable by previous imaging missions.
Further observation of PKS 0438-436
Researchers found there are two unusual aspects of this luminous blazar. Firstly, its the large L151, typically indicative of luminous radio lobes in which energy is stored and the lack of a detection in the gamma-rays to date.
The large-scale radio structure and the jet power
To investigate on this matter, researchers determined the radio lobe morphology and flux density to get an estimate the long-term, time-averaged radio jet power. Such estimates of instantaneous blazar jet power are often based on its radio core and γ-ray emission, according to methods of Ghisellini et al. (2010) and the estimated Doppler enhancement factor, D, can introduce very significant uncertainty. Estimating Q from the lobe luminosity of PKS 0438-436 is not instantaneous power. Yet, it has the virtue that the lobe luminosity and therefore Q not sensitive to the large uncertainty in D.
Researchers utilized the estimate of Q through the Oxford method. This was calibrated with a sample of 170 double-lobe radio sources which were selected on the basis of low-frequency emission (151 MHz–178 MHz). The calibrated estimator depends on only one parameter, a single value of flux density which is used as a surrogate for the flux density restricted to the radio lobes. This is the strength of the method; a single dish measurement at low frequency can be used to estimate Q for sources not in the calibration sample. Thus, a single-dish measurement is not applicable to blazars in general due to dilution of the lobe flux density with core and jet flux density.
As for choice of L151, it is used as a surrogate for the luminosity of the radio lobes, motivated by the assumption that the core emission is attenuated by synchrotron self-absorption at 151 MHz. (Willott et al. 1999) The energy stored in the lobes, U, can be estimated from L151 and since the lobe plasma has low velocity this value will not be strongly affected by D. They calculated the equation as Q = fUbase (L151) divided by T proposed by Willott et al. (1999), where T is the source age, Ubase(L151) is the minimum energy in the lobe assuming a low-frequency cut-off at 10 MHz, the jet axis is 60° to the line of sight (LOS), there is no protonic contribution, and 100% filling factor. The quantity f incorporates deviations of actual radio lobes from these assumptions as well as energy lost through expanding the lobe into the external medium, back flow from the head of the lobe, and kinetic turbulence.
From there, the equation relating T and Q (EQW9 hereafter) is derived by considering the evolution of the lobe dimension, R, in models of lobe head advance into an ambient medium. Differentiating EQW9 yields an equation for dR/dt (EQW10 hereafter) which is equated to the lobe advance speeds derived from the distribution of length asymmetry between the two lobes of a sample of quasars. EQW4, EQW9, and EQW10 were solved simultaneously to eliminate R and T, yielding as a function of f and L151 which is presented in a scatter plot of the calibration sample according to Willott et al. (1999) where Q ≈ 3.8 x 1045 fL 6/7151 ergs−1. There, they were able to collect the data, whom they calculated it as Q = 1.65 + 0.55 x 1047 ergs−1.
Nature of radio lobes and jet power
Researcher noted the northeast and southwest extensions in emission were detected in 327 MHz, according to Very Long Baseline Array (VLBA) observations of Kanekar et al. (2009). These features appear to be a partially resolved jet and counter-jet on scales ~100 mas from the unresolved radio core. These smaller-scale features are buried deep within the unresolved JVLA radio core (i.e., an order of magnitude smaller than the resolution of the 2.5 GHz observations). The jet and counter-jet directions detected with the VLBA are consistent with jets that connect to the extended emission. For this, they confirmed PKS 0438–436 as a classical radio source, which they assume the radio lobes is αlobe = 0.9. Using the estimated calculation of radio lobes as well as the lobe flux density at 2.5 GHz, and values of (L151 3.0 x 1028 W Hz−1 sr−1) and (Q = 1.14 + 0.38 x1047 erg s−1), this suggests the previous calculation is overestimated due to core and jet contributions to the 160 MHz flux density. The newest calculation is more accurate since the method of Willott et al. (1999) assumes that L151 is a surrogate for the lobe luminosity. If αlobe were 1.05 then the 7.9 Jy single-dish flux density at 160 MHz could be attributed entirely to the lobes. However, a spectrum this steep is an extremely rare circumstance.
Luminosity of accretion flow
Researchers then analyzed the optical spectrum to get an estimate of the thermal bolometric luminosity of the accretion flow, Lbol. This was obtained, to quantify the thermal luminosity of the accretion flow and the strength of the broad emission lines. Due to the high redshift, the ultraviolet emission line spectrum is redshifted into the optical band. The earlier spectrum (1977 November 18) is from the RGO spectrograph on the 3.9 m Anglo Australian Telescope and this observation was used in the original determination of the quasar properties and redshift.
The spectra from UVES, the Ultraviolet and Visual Echelle Spectrograph, on the VLT were retrieved from the ESO Spectral Data Products of the Phase 3 archive portal. The UVES spectrum shows the results from the combination of 11 flux-calibrated spectra. On September 14, 2002, a total of eight spectra were taken: four covering 3730 Å–5000 Å and four covering 6650 Å–10420 Å. On October 30, 2003, three spectra covering 4720 Å–6830 Å were combined. A gap is present on the blue side of the redshifted CIVλ1549, but the profile is presumably unaffected. There is also a small absolute flux mismatch around 6800 Å between 2002 and 2003. The spectral resolution of UVES is about R = λ/δλ ~ 40,000 with the slit opened to 1008. Researchers estimated the flux density of the continuum as F (6600 A) 1.2 x10−16 ergs−1 cm−2 A−1 and F (6600 A) 6.0 x 10−17 ergs−1 cm−2 A−1.
Gamma-Ray Flare
A preliminary FERMI detection of PKS 0438–436 on December 11, 2016, was observed by Large Area Telescope; it previously had no gamma-ray detections. An analysis of Fermi-LAT data was performed on PKS 0438-436 using the fermipy framework. The data were selected over a time span of six days, between 57731.0 MJD 57737.0 MJD, which researchers selected photons from a region of interest (ROI) with a radius of 10°, centered on PKS 0438–436, and built a model of the ROI using sources within 15° distance from the ROI center and reported in the Fermi-LAT Third Source Catalog (Acero et al. 2015), including both the emission from the Galactic diffuse and the isotropic backgrounds.
For the light curve extraction, researchers used bins of 18 hr, for a time range starting on MJD 57731.00 and ending on MJD 57736.25. For each bin a binned likelihood analysis was performed, using a power-law function, and freeing all the sources located within a distance of 5° from the ROI center. The light curve is shown, in which data reports the integrated photon flux in the 100 MeV–100 GeV energy range, and the corresponding apparent luminosity. The source is detected in four bins with a significance, and the flaring activity in concentrated over a time span of 54 hr centered on MJD 57734.4.
The source from PKS 0438-436 is detected with a significance of ≳10σ during the full flare period, and with a significance ranging from ≳3σ to ≳8σ, during each time bin. There is formally no detection above 10 GeV, only upper limits. The lack of detected photons arises from two conspiring issues. First is the large distance that makes for low number statistics even for this very luminous flare. Second is the EBL (extra background light) opacity. Gamma-ray extinction occurs as a consequence of pair creation in the soft background photon field.
They have calculated the EBL attenuation using the γ − γ optical depths evaluated at z = 2.85 from the template model from Finke et al. (2010). The red dotted–dashed line shows an expected attenuation, which the EBL starts to be relevant above ≈70 GeV, and the upper limits in spectral energy distributions (SEDs) starts at ≈10 GeV.
Using the SWIFT spectrum, observed two days after the flare, obtained using the Swift XRT product generator10, the X-ray spectrum is more luminous and harder than historical X-ray spectra. The data are not contemporaneous, but the strong inverse Compton γ-ray peak >5 × 1049 erg s−1 is much stronger than the synchrotron peak, ~2 × 1047 erg s−1, characteristic of strong quasar gamma-ray sources. The luminosity of the flare is ~100 times the quiescent upper limit (August 4, 2008 – July 4, 2009) in Böck et al. (2013), indicating extreme variability. Since it is rarely detected, the time-averaged γ-ray luminosity is not extreme. However, the flare is ≈55%–65% as luminous (in an 18 hr window) as the historically large flare of 3C 454.3 even though the peak of the SED is redshifted out of the FERMI observing window.
Considering D, PKS 0438-436 is of interest to estimate the intrinsic luminosity of the flare. For an unresolved source, D = δ3+a, where δ is the Doppler factor, the value of D ≈ 154 ≈ 5 x 104using the average of δ = 15, high optical polarization quasars are estimated from time variability. This implies an intrinsic luminosity of the flare. These radiation losses are easily sustainable by a jet with a power similar to the long-term time average. This findings suggest, PKS 0438-436 has only been detected once in γ-rays, likely an extreme manifestation of external Compton scattering in a relativistic jet for which the apparent luminosity is very sensitive to the geometry.
References
Quasars
Caelum
Blazars
Active galaxies
2824039 | PKS 0438-436 | [
"Astronomy"
] | 2,838 | [
"Caelum",
"Constellations"
] |
77,002,430 | https://en.wikipedia.org/wiki/Aza-Wittig%20reaction | The Aza-Wittig reaction or is a chemical reaction of a carbonyl group with an aza-ylide, also known as an iminophosphorane (). Aza-Wittig reactions are most commonly used to convert aldehydes and ketones to the corresponding imines. The conversion has also been practiced in an intramolecular sense, which is commonly used in the synthesis of N-heterocyclic compounds.
Reaction mechanism
The mechanism of the aza-Wittig reaction is analogous to that of the Wittig reaction, with the Wittig reagent replaced by an iminophosphorane.
In some cases, the iminophosphorane is not isolated but generated in situ. In this manifestation, the phosphine, carbonyl, and organic azide are combined
Scope and limitations
Besides preparing imines from aldehydes and ketones, the aza-Wittig-reaction can also convert carbon dioxide to isocyanates, carbon disulfide to organic thiocyanates, and isocyanates to carbodiimides.
There exists solid-supported modifications of the reaction.
Similar to the Wittig reaction, the reaction suffers from issues with triphenylphosphine oxide by-product removal. Such an issue is mitigated via catalytic aza-Wittig-reactions, some of which entail elements other than phosphorus, like arsenic and tellurium.
History
The reagent for the aza-Wittig reaction, iminophosphorane, was discovered in 1919 by Hermann Staudinger. The reaction itself was discovered thirty years later.
Examples
An example of the aza-Wittig-reaction being utilized in organic synthesis is the synthesis of (–)-benzomalvin A. Two intramolecular aza-Wittig-reactions were used to construct the seven-membered ring and the six-membered ring in the molecule's skeleton.
See also
Staudinger reaction
Schiff base
Wittig reaction
Imine
References
External links
Wittig reaction in Organic Syntheses, Coll. Vol. 10, p. 703 (2004); Vol. 75, p. 153 (1998). (Article)
Wittig reaction in Organic Syntheses, Coll. Vol. 5, p. 361 (1973); Vol. 45, p. 33 (1965). (Article)
Name reactions | Aza-Wittig reaction | [
"Chemistry"
] | 518 | [
"Name reactions"
] |
77,002,473 | https://en.wikipedia.org/wiki/Q%20tensor | In physics, tensor is an orientational order parameter that describes uniaxial and biaxial nematic liquid crystals and vanishes in the isotropic liquid phase. The tensor is a second-order, traceless, symmetric tensor and is defined by
where and are scalar order parameters, are the two directors of the nematic phase and is the temperature; in uniaxial liquid crystals, . The components of the tensor are
The states with directors and are physically equivalent and similarly the states with directors and are physically equivalent.
The tensor can always be diagonalized,
The following are the invariants of the tensor
the first-order invariant is trivial here. It can be shown that The measure of biaxiality of the liquid crystal is commonly measured through the parameter
Uniaxial nematics
In uniaxial nematic liquid crystals, and therefore the tensor reduces to
The scalar order parameter is defined as follows. If represents the angle between the axis of a nematic molecular and the director axis , then
where denotes the ensemble average of the orientational angles calculated with respect to the distribution function and is the solid angle. The distribution function must necessarily satisfy the condition since the directors and are physically equivalent.
The range for is given by , with representing the perfect alignment of all molecules along the director and representing the complete random alignment (isotropic) of all molecules with respect to the director; the case indicates that all molecules are aligned perpendicular to the director axis although such nematics are rare or hard to synthesize.
See also
Landau–de Gennes theory
References
Soft matter
Phase transitions
Liquid crystals | Q tensor | [
"Physics",
"Chemistry",
"Materials_science"
] | 328 | [
"Physical phenomena",
"Phase transitions",
"Soft matter",
"Phases of matter",
"Critical phenomena",
"Condensed matter physics",
"Statistical mechanics",
"Matter"
] |
77,002,567 | https://en.wikipedia.org/wiki/Landau%E2%80%93de%20Gennes%20theory | In physics, Landau–de Gennes theory describes the NI transition, i.e., phase transition between nematic liquid crystals and isotropic liquids, which is based on the classical Landau's theory and was developed by Pierre-Gilles de Gennes in 1969. The phenomonological theory uses the tensor as an order parameter in expanding the free energy density.
Mathematical description
The NI transition is a first-order phase transition, albeit it is very weak. The order parameter is the tensor, which is symmetric, traceless, second-order tensor and vanishes in the isotropic liquid phase. We shall consider a uniaxial tensor, which is defined by
where is the scalar order parameter and is the director. The tensor is zero in the isotropic liquid phase since the scalar order parameter is zero, but becomes non-zero in the nematic phase.
Near the NI transition, the (Helmholtz or Gibbs) free energy density is expanded about as
or more compactly
Further, we can expand , and with being three positive constants. Now substituting the tensor results in
This is minimized when
The two required solutions of this equation are
The NI transition temperature is not simply equal to (which would be the case in second-order phase transition), but is given by
is the scalar order parameter at the transition.
References
Soft matter
Phase transitions
Liquid crystals | Landau–de Gennes theory | [
"Physics",
"Chemistry",
"Materials_science"
] | 284 | [
"Physical phenomena",
"Phase transitions",
"Soft matter",
"Phases of matter",
"Critical phenomena",
"Condensed matter physics",
"Statistical mechanics",
"Matter"
] |
77,002,804 | https://en.wikipedia.org/wiki/Simon%20Olivier | Simon Cornelis Johannes Olivier (Amsterdam, June 13, 1879 – Wageningen, August 9, 1961) was a Dutch chemist. He was professor at the Wageningen Agricultural College (predecessor of what is currently Wageningen University) from 1919 to 1949. During the Second World War he was imprisoned for almost two years for his resistance against the German occupier.
Career
Olivier studied chemistry at the Delft University of Technology. He received his doctorate in 1913 cum laude (“with high distinction”) as a doctor of technical science for his study of “Velocity measurements in the reaction of Friedel and Crafts” [translated from Dutch]. He subsequently worked as an assistant at the National Agricultural Research Station in Groningen, and as a physics and chemistry teacher at the HBS in Nijmegen. Subsequently, he got a job at the Wageningen Agricultural College. In 1918 he was appointed professor of Organic Chemistry, the first professor of the current Laboratory of Organic Chemistry. Olivier's publications also attracted attention abroad, especially in the field of organic chemistry.
WWII
Olivier was concerned about Nazism well before the German invasion of the Netherlands. Already in 1936 he became a member of the Committee of Vigilance of Anti-National Socialist Intellectuals. He also advocated admission of Jewish refugees from Nazi Germany.
Olivier was one of the few employees of the Wageningen Agricultural College who objected when they were asked to hand in an Aryan declaration in 1940. According to him, the statement was "the introduction of discrimination against Jews in the Netherlands". When he was informed that this could give him terrorist status, he crossed out the form and completed a new questionnaire. Nevertheless, Olivier continued to speak out against National Socialist ideas.
After members of the National Socialist Movement (in Dutch: NSB) –a Dutch fascist movement that affiliated with the Nazis– had plastered Wageningen on July 18, 1941 with notes from the German V-action (the taking over of 'V=Victory' by the Germans “because Germany is winning on all fronts”) and especially the main building of the Wageningen Agricultural College, Olivier ordered a worker to remove everything. A few days later he was taken into custody. After 11 months in prison in Amersfoort, where, as he put it, “he became more closely acquainted with the methods the Germans use to bring opponents to reason”, he was dismissed from his academic position and expelled from Wageningen. He was initially locked up in the infamous Oranjehotel in Scheveningen, and subsequently imprisoned in various German concentration camps until 1943, when he was released due to his poor health. However, Olivier was banned from publishing and was no longer allowed to appear in university cities.
Post WWII
After the war, Olivier was appointed Rector Magnificus of the Wageningen Agricultural College for the year 1945-1946. He had previously been rector in Wageningen in the academic year 1923-1924. Olivier retired in 1949.
References
Dutch chemists
1879 births
1961 deaths | Simon Olivier | [
"Chemistry"
] | 613 | [
"Organic chemists"
] |
77,003,143 | https://en.wikipedia.org/wiki/Lead%28II%29%20phthalocyanine | Lead(II) Phthalocyanine (PbPc), also known as phthalocyanine lead, is a salt consisting of a lead ion and Pc2−, the conjugate base of pythalocyanine. It is a organolead dye and bright purple powder. It's also used as a near infared light absorber for photodetectors. It has a unique structural feature which is called and resembles a "shuttle cock."
References
Phthalocyanines
Macrocycles
Lead(II) compounds
Organic pigments | Lead(II) phthalocyanine | [
"Chemistry"
] | 119 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs",
"Macrocycles"
] |
77,003,769 | https://en.wikipedia.org/wiki/Ning%20Zheng | Ning Zheng is an experimental structural biologist and protein biochemist known for his pioneering work in the fields of molecular glues and targeted protein degradation. He is currently a professor in the Department of Pharmacology at the University of Washington School of Medicine and a Howard Hughes Medical Institute (HHMI) Investigator.
Education and training
The son of a Chinese biochemistry professor, Ning Zheng obtained his Ph.D. in 1997 from the University of Texas Southwestern Medical Center.
He completed his postdoctoral studies at the Memorial Sloan-Kettering Cancer Center under the mentorship of Nikola Pavletich, where he published two seminal studies on the atomic structures of prototypical human ubiquitin ligase complexes. These studies laid the foundation for his subsequent research and contributions to structural biology and protein ubiquitination.
Research
Ning Zheng’s research focuses on the molecular and structural mechanisms by which protein-protein interactions regulate eukaryotic biology and human diseases. His laboratory has made significant contributions to understanding the cullin-RING superfamily of E3 ubiquitin ligases, which is implicated in a myriad of cellular functions such as signal transduction, cell cycle regulation, transcriptional control, and DNA repair.
Zheng's recent studies have expanded to several areas of life sciences, including protein degradation, plant hormone signaling, circadian clock regulation, chromatin modification, and the structure-function relationships of ion channels and transporters. His groundbreaking work on the perception mechanism of the plant hormone auxin led to the introduction of the concept of "molecular glue." This concept describes how monovalent small molecules can promote protein-protein interactions by complementing protein interfaces, facilitating targeted-protein degradation. This conceptual advance has become instrumental in the development of novel therapeutic compounds for targeting disease-causing proteins considered undruggable. His laboratory is actively involved in drug discovery programs aimed at treating challenging human diseases, such as cancers and neurodegenerative disorders.
Awards and recognition
Throughout his career, Ning Zheng has received numerous accolades. After joining the faculty of Pharmacology at the University of Washington, he was awarded the Pew Scholar Award and the Burroughs Welcome Investigator Award in Pathogenesis of Infectious Diseases. In 2008, he became a Howard Hughes Medical Institute Investigator. He was promoted to Professor in 2012. His significant contributions to science have been recognized through his election as a Fellow of the American Association for the Advancement of Science (AAAS) in 2015 and as a member of the Washington State Academy of Science in 2020.
Selected publications
Cao, S., Kang, S., Mao, H. et al. Defining molecular glues with a dual-nanobody cannabidiol sensor. Nat Commun 13, 815 (2022). https://doi.org/10.1038/s41467-022-28507-1
Sheard, L., Tan, X., Mao, H. et al. Jasmonate perception by inositol-phosphate-potentiated COI1–JAZ co-receptor. Nature 468, 400–405 (2010). https://doi.org/10.1038/nature09430
Tan, X., Calderon-Villalobos, L., Sharon, M. et al. Mechanism of auxin perception by the TIR1 ubiquitin ligase. Nature 446, 640–645 (2007). https://doi.org/10.1038/nature05731
Angers, S., Li, T., Yi, X. et al. Molecular architecture and assembly of the DDB1–CUL4A ubiquitin ligase machinery. Nature 443, 590–593 (2006). https://doi.org/10.1038/nature05175
Goldenberg, S.J., Cascio, T.C., Shumway, S.D. et al. Structure of the Cand1-Cul1-Roc1 complex reveals regulatory mechanisms for the assembly of the multisubunit cullin-dependent ubiquitin ligases. Cell, 12;119(4):517-28. (2004). https://doi.org/10.1016/j.cell.2004.10.019
Zheng, N., Schulman, B., Song, L. et al. Structure of the Cul1–Rbx1–Skp1–F boxSkp2 SCF ubiquitin ligase complex. Nature 416, 703–709 (2002). https://doi.org/10.1038/416703a
External links
University of Washington faculty page
Howard Hughes Medical Institute profile
Lab website
References
Living people
Structural biologists
Year of birth missing (living people)
American biochemists
University of Washington faculty
Howard Hughes Medical Investigators
University of Texas Southwestern Medical Center alumni
Fellows of the American Association for the Advancement of Science | Ning Zheng | [
"Chemistry"
] | 1,029 | [
"Structural biologists",
"Structural biology"
] |
77,004,618 | https://en.wikipedia.org/wiki/List%20of%20most%20massive%20star%20clusters | Below are lists of the most massive known star clusters in solar masses () and sorted in descending order.
Methods for mass estimation
Globular cluster
Globular cluster masses can be determined by observing the proper motion of nearby stars influenced by the cluster or by estimating the cluster's relaxation time.
Open clusters
The masses of open star clusters can be estimated by measuring the falloff of radial and tangential velocities of surrounding stars at a particular distance.
List
Globular clusters
Open clusters
See also
List of largest star clusters
References
External links
The young cluster RMC 136a European Southern Observatory
Mayall II Messier Objects
Monster Super Star Cluster Discovered In Milky Way ScienceDaily
Star clusters
Astronomy-related lists | List of most massive star clusters | [
"Astronomy"
] | 145 | [
"Astronomy-related lists",
"Astronomical objects",
"Star clusters"
] |
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