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65,231,607 | https://en.wikipedia.org/wiki/MethaneSAT | MethaneSAT is an American-New Zealand space mission launched in 2024 aboard SpaceX's Transporter 10 rideshare mission. It is an Earth observation satellite that will monitor and study global methane emissions in order to combat climate change. The spacecraft will carry a high performance spectrometer methane sensing system, which will allow the spacecraft to take high resolution measurements of global methane emissions from roughly 50 major regions across Earth.
The mission is jointly funded and operated by the Environmental Defense Fund (EDF), an American non-governmental organization, and the New Zealand Space Agency. It marks New Zealand's first space science mission. The Bezos Earth Fund, founded by Jeff Bezos, announced a US$100 million grant to EDF that will support critical work including completion and launch of MethaneSAT. Sara Mikaloff-Fletcher, a National Institute of Water and Atmospheric Research (NIWA) carbon cycle expert, has been named as the mission's lead scientist.
History
The MethaneSAT program was started by MethaneSAT, LLC, a wholly owned subsidiary of the Environmental Defense Fund (EDF), with the goal of providing global high resolution data regarding methane emissions from oil and gas facilities. In January 2020, MethaneSAT announced that the spacecraft will be built using the Blue Canyon Technologies X-SAT satellite bus, with the spacecraft's methane sensing spectrometer being provided by Ball Aerospace & Technologies.
In November 2019, the New Zealand Space Agency (NZSA) joined the program, committing NZ$26 million to the program. Rocket Lab will build and operate the mission control center for the flight in Auckland, New Zealand. NZSA will also take part in launch operations and may contribute to the scientific payload.
Ball Aerospace and Blue Canyon Technologies completed an intensive technology review of their respective contributions to the mission in early 2020.
On 13 January 2021, the nonprofit MethaneSAT LLC announced that it had signed a contract with SpaceX to deliver the 350 kg MethaneSAT into orbit aboard a Falcon 9 Block 5 launch vehicle with a launch window opening on 1 October 2022.
By November 2022, the launch had been delayed to NET October 2023 by supply chain issues during the Covid-19 pandemic. The satellite launched as part of Transporter 10 on 4 March 2024.
Results
Early reports using the MethaneSat equipment mounted on a jet aircraft (MethaneAir) showed that oil and gas producers in the U.S. are emitting methane into the atmosphere at over four times the rates estimated by the Environmental Protection Agency. The largest emitter is the Permian Basin in Texas which is emitting 256 tons of methane every day, accounting for 1.9% of total gas production. This is in addition to the CO2 produced by extensive gas flaring in the region.
Across continental U.S. the aggregate methane loss rate across 12 basins amounts to 1.6% of gas produced, which is 8 times higher than the 0.2% emissions intensity target adopted by the Oil and Gas Climate Initiative.
References
Spacecraft launched in 2024
Methane
Earth observation satellites
Satellites of New Zealand
Satellites monitoring GHG emissions | MethaneSAT | [
"Chemistry"
] | 626 | [
"Greenhouse gases",
"Methane"
] |
65,231,638 | https://en.wikipedia.org/wiki/Droplet%20nucleus | Droplet nuclei are aerosols formed from the evaporation of respiratory droplets. They are generally smaller than 5 μm in diameter. Droplet nuclei are formed by the "dried residua of larger respiratory droplets". These particles are "the vehicle for airborne respiratory disease transmission, which are the dried-out residual of droplets possibly containing infectious pathogens". Diseases such as tuberculous and COVID-19 can be transmitted via droplet nuclei.
See also
Basic reproduction number
References
Disease transmission
Particulates | Droplet nucleus | [
"Chemistry"
] | 106 | [
"Particulates",
"Particle technology"
] |
65,233,966 | https://en.wikipedia.org/wiki/2020%20Narayanganj%20explosion | On 4 September 2020, an explosion in Baitus Salat Jame mosque in Narayanganj District, Bangladesh killed at least 31 people while dozens more were injured. The death toll rose to 31 on 10 September.
Causes
The explosion is presumed to have been caused by a gas leak from an underground pipeline. At around 8:30 pm local time, all the six air conditioning units installed on the ground floor exploded simultaneously. Earlier, there were power outages in the mosque and a sudden surge of electricity caused sparks on the air conditioners which may have led to the explosion.
See also
List of explosions
References
2020 disasters in Bangladesh
2020 fires in Asia
Gas explosions
Mosque fires
Explosions in 2020
Industrial fires and explosions in Bangladesh
2020 in Islam
Narayanganj Sadar Upazila
September 2020 events in Bangladesh
History of Islam in Bangladesh
Building and structure fires in Bangladesh | 2020 Narayanganj explosion | [
"Chemistry"
] | 169 | [
"Natural gas safety",
"Gas explosions"
] |
65,234,277 | https://en.wikipedia.org/wiki/Taxonomy%20of%20diatoms | Diatoms belong to a large group called the heterokonts, which include both autotrophs such as golden algae and kelp; and heterotrophs such as water moulds. The classification of heterokonts is still unsettled: they may be designated a division, phylum, kingdom, or something intermediate to those. Consequently, diatoms are ranked anywhere from a class, usually called Diatomophyceae or Bacillariophyceae, to a division (=phylum), usually called Bacillariophyta, with corresponding changes in the ranks of their subgroups.
Genera and species
An estimated 20,000 extant diatom species are believed to exist, of which around 12,000 have been named to date according to Guiry, 2012 (other sources give a wider range of estimates). Around 1,000-1,300 diatom genera have been described, both extant and fossil, of which some 250-300 exist only as fossils.
Classes and orders
Overview
For many years the diatoms—treated either as a class (Bacillariophyceae) or a phylum (Bacillariophyta)—were divided into just 2 orders, corresponding to the centric and the pennate diatoms (Centrales and Pennales; alternative names Biddulphiales and Bacillariales, as used e.g. in Lee, 1989). This classification was extensively overhauled by Round, Crawford and Mann in 1990 who treated the diatoms at a higher rank (division, corresponding to phylum in zoological classification), and promoted the major classification units to classes, maintaining the centric diatoms as a single class Coscinodiscophyceae, but splitting the former pennate diatoms into 2 separate classes, Fragilariophyceae and Bacillariophyceae (the latter older name retained but with an emended definition), between them encompassing 45 orders, the majority of them new.
Today (writing at mid 2020) it is recognised that the 1990 system of Round et al. is in need of revision with the advent of newer molecular work, however the best system to replace it is unclear, and current systems in widespread use such as AlgaeBase, the World Register of Marine Species and its contributing database DiatomBase, and the system for "all life" represented in Ruggiero et al., 2015, all retain the Round et al. treatment as their basis, albeit with diatoms as a whole treated as a class rather than division/phylum, and Round et al.'s classes reduced to subclasses, for better agreement with the treatment of phylogenetically adjacent groups and their containing taxa. (For references refer the individual sections below).
One proposal, by Linda Medlin and co-workers commencing in 2004, is for some of the centric diatom orders considered more closely related to the pennates to be split off as a new class, Mediophyceae, itself more closely aligned with the pennate diatoms than the remaining centrics. This hypothesis—later designated the Coscinodiscophyceae-Mediophyceae-Bacillariophyceae, or Coscinodiscophyceae+(Mediophyceae+Bacillariophyceae) (CMB) hypothesis—has been accepted by D.G. Mann among others, who uses it as the basis for the classification of diatoms as presented in Adl. et al.'s series of syntheses (2005, 2012, 2019), and also in the Bacillariophyta chapter of the 2017 Handbook of the Protists edited by Archibald et al., with some modifications reflecting the apparent non-monophyly of Medlin et al. original "Coscinodiscophyceae". Meanwhile, a group led by E.C. Theriot favours a different hypothesis of phylogeny, which has been termed the structural gradation hypothesis (SGH) and does not recognise the Mediophyceae as a monophyletic group, while another analysis, that of Parks et al., 2018, finds that the radial centric diatoms (Medlin et al.'s Coscinodiscophyceae) are not monophyletic, but supports the monophyly of Mediophyceae minus Attheya, which is an anomalous genus. Discussion of the relative merits of these conflicting schemes continues by the various parties involved.
Round et al., 1990
Based on the fact that pennate diatoms either do or do not have a longitudinal groove in the valve, called a raphe, a 1990 classification by Round, Crawford & Mann divides the diatoms (as Bacillarophyta) into three classes, centric (22 orders); pennate without a raphe (12 orders); and pennate with a raphe (11 orders), as follows:
Phylum Bacillarophyta (diatoms)
Class Coscinodiscophyceae Round & R.M.Crawford (centric diatoms)
Subclass Biddulphiophycidae Round & R.M.Crawford
Anaulales Round & R.M.Crawford
Biddulphiales Krieger
Hemiaulales Round & R.M.Crawford
Triceratiales Round & R.M.Crawford
Subclass Chaetocerotophycidae Round & R.M.Crawford
Chaetocerotales Round & R.M.Crawford
Leptocylindrales Round & R.M.Crawford
Subclass Corethrophycidae Round & R.M.Crawford
Corethrales Round & R.M.Crawford
Subclass Coscinodiscophycidae Round & R.M.Crawford
Arachnoidiscales Round
Asterolamprales Round
Aulacoseirales R.M.Crawford
Chrysanthemodiscales Round
Coscinodiscales Round
Ethmodiscales Round
Melosirales R.M.Crawford
Orthoseirales R.M.Crawford
Paraliales R.M.Crawford
Stictocyclales Round
Stictodiscales Round & R.M.Crawford
Subclass Cymatosirophycidae Round & R.M.Crawford
Cymatosirales Round & R.M.Crawford
Subclass Lithodesmiophycidae Round & R.M.Crawford
Lithodesmiales Round & R.M.Crawford
Subclass Rhizosoleniophycidae Round & R.M.Crawford
Rhizosoleniales Silva
Subclass Thalassiosirophycidae Round & R.M.Crawford
Thalassiosirales Glezer & Makarova
Class Fragilariophyceae Round (pennate diatoms without a raphe (araphids))
Subclass Fragilariophycidae Round
Ardissoneales Round
Climacospheniales Round
Cyclophorales Round & R.M.Crawford
Fragilariales P.C.Silva
Licmophorales Round
Protoraphidales Round
Rhabdonematales Round & R.M.Crawford
Rhaphoneidales Round
Striatellales Round
Tabellariales Round
Thalassionematales Round
Toxariales Round
Class Bacillariophyceae Haeckel, 1878, emend. D.G.Mann (pennate diatoms with a raphe (raphids))
Subclass Bacillariophycidae D.G.Mann
Achnanthales P.C.Silva
Bacillariales Hendey
Cymbellales D.G.Mann
Dictyoneidales D.G.Mann
Lyrellales D.G.Mann
Mastogloiales D.G.Mann
Naviculales Bessey
Rhopalodiales D.G.Mann
Surirellales D.G.Mann
Thalassiophysales D.G.Mann
Subclass Eunotiophycidae D.G.Mann
Eunotiales P.C.Silva
Medlin & Kaczmarska, 2004
An alternate classification for the diatoms based on molecular phylogeny was proposed by Medlin & Kaczmarska in 2004, as follows. Medlin and co-workers erected a new class, Mediophyceae (which could be re-ranked a subclass if diatoms as a whole are ranked as a class rather than a phylum) for the "polar centric" diatoms, which they consider to be more closely related to the pennate rather than to other centric diatoms, a concept which has been followed or further adapted by some (e.g. Adl et al., 2019, see below), but not all subsequent workers at this time.
Phylum Bacillariophyta (diatoms)
Subphylum Coscinodiscophytina
Class Coscinodiscophyceae ("radial centrics")
Arachnoidiscales
Asterolamprales
Aulacoseirales
Corethrales
Coscinodiscales
Chrysanthemodiscales
Ethmodiscales
Leptocylindrales
Melosirales
Orthoseirales
Rhizosoleniales
Stictocyclales
Stictodiscales
Subphylum Bacillariophytina
Class Mediophyceae ("polar centrics")
Ardissoneales
Biddulphiales
Chaetocerotales
Cymatosirales
Hemiaulales
Lithodesmiales
Thalassiosirales
Toxariales
Triceratiales
Class Bacillariophyceae (pennate diatoms)
Achnanthales
Bacillariales
Cymbellales
Dictyoneidales
Eunotiales
Fragilariales
Licmophorales
Lyrellales
Mastogloiales
Naviculales
Rhabdonematales
Rhaphoneidales
Rhopalodiales
Surirellales
Tabellariales
Thalassionematales
Thalassiophysales
Ruggiero et al., 2015
In the treatment for "all life" (down to order, extant taxa only) by Ruggiero et al., 2015, the diatoms are treated as follows. This treatment largely reflects that used by Algaebase as at 2015, and is also reflected in the current (mid 2020) treatment used in DiatomBase, the World Register of Marine Species (WoRMS) of which DiatomBase is a part, and the Catalogue of Life. This treatment is identical to that of Round et al., 1990, except that all diatoms are treated as a single class, Round et al.'s classes are reduced to subclasses, and the latter's original subclasses are omitted.
Superphylum Heterokonta (heterokonts: Ochrophyta plus other phyla))
Phylum Ochrophyta (diatoms plus other classes)
Class Bacillariophyceae (diatoms)
Subclass Bacillariophycidae
Achnanthales
Bacillariales
Cymbellales
Dictyoneidales
Eunotiales
Lyrellales
Mastogloiales
Naviculales
Rhopalodiales
Surirellales
Thalassiophysales
Subclass Coscinodiscophycidae
Anaulales
Arachnoidiscales
Asterolamprales
Aulacoseirales
Biddulphiales
Chaetocerotales
Chrysanthemodiscales
Corethrales
Coscinodiscales
Cymatosirales
Ethmodiscales
Hemiaulales
Leptocylindrales
Lithodesmiales
Melosirales
Orthoseirales
Paraliales
Rhizosoleniales
Stictocyclales
Stictodiscales
Thalassiosirales
Triceratiales
Subclass Fragilariophycidae
Ardissoneales
Climacospheniales
Cyclophorales
Fragilariales
Licmophorales
Protoraphidales
Rhabdonematales
Rhaphoneidales
Striatellales
Tabellariales
Thalassionematales
Toxariales
Adl et al., 2019
Following earlier versions in the treatments of Adl et al. 2005 and 2012, D.G. Mann, in Adl et al. 2019, presented his most recent classification of diatoms as follows, while noting: "This revision reflects numerous advances in the phylogeny of the diatoms over the last decade. Due to our poor taxon sampling outside of the Mediophyceae and pennate diatoms, and the known and anticipated diversity of all diatoms, many clades appear at a high classification level (and the higher level classification is rather flat)." This classification treats diatoms as a phylum (Diatomeae/Bacillariophyta), accepts the class Mediophyceae of Medlin and co-workers, introduces new subphyla and classes for a number of otherwise isolated genera, and re-ranks a number of previously established taxa as subclasses, but does not list orders or families. Inferred ranks have been added for clarity (Adl. et al. do not use ranks, but the intended ones in this portion of the classification are apparent from the choice of endings used, within the system of botanical nomenclature employed).
Clade Diatomista Derelle et al. 2016, emend. Cavalier-Smith 2017 (diatoms plus a subset of other ochrophyte groups)
Phylum Diatomeae Dumortier 1821 [= Bacillariophyta Haeckel 1878] (diatoms)
Subphylum Leptocylindrophytina D.G. Mann in Adl et al. 2019
Class Leptocylindrophyceae D.G. Mann in Adl et al. 2019 (Leptocylindrus, Tenuicylindrus)
Class Corethrophyceae D.G. Mann in Adl et al. 2019 (Corethron)
Subphylum Ellerbeckiophytina D.G. Mann in Adl et al. 2019 (Ellerbeckia)
Subphylum Probosciophytina D.G. Mann in Adl et al. 2019 (Proboscia)
Subphylum Melosirophytina D.G. Mann in Adl et al. 2019 (Aulacoseira, Melosira, Hyalodiscus, Stephanopyxis, Paralia, Endictya)
Subphylum Coscinodiscophytina Medlin & Kaczmarska 2004, emend. (Actinoptychus, Coscinodiscus, Actinocyclus, Asteromphalus, Aulacodiscus, Stellarima)
Subphylum Rhizosoleniophytina D.G. Mann in Adl et al. 2019 (Guinardia, Rhizosolenia, Pseudosolenia)
Subphylum Arachnoidiscophytina D.G. Mann in Adl et al. 2019 (Arachnoidiscus)
Subphylum Bacillariophytina Medlin & Kaczmarska 2004, emend.
Class Mediophyceae Jouse & Proshkina-Lavrenko in Medlin & Kaczmarska 2004
Subclass Chaetocerotophycidae Round & R.M. Crawford in Round et al. 1990, emend.
Subclass Lithodesmiophycidae Round & R.M. Crawford in Round et al. 1990, emend.
Subclass Thalassiosirophycidae Round & R.M. Crawford in Round et al. 1990
Subclass Cymatosirophycidae Round & R.M. Crawford in Round et al. 1990
Subclass Odontellophycidae D.G. Mann in Adl et al. 2019
Subclass Chrysanthemodiscophycidae D.G. Mann in Adl et al. 2019
Class Biddulphiophyceae D.G. Mann in Adl et al. 2019
Subclass Biddulphiophycidae Round and R.M. Crawford in Round et al. 1990, emend.
Biddulphiophyceae incertae sedis (Attheya)
Class Bacillariophyceae Haeckel 1878, emend.
Bacillariophyceae incertae sedis (Striatellaceae)
Subclass Urneidophycidae Medlin 2016
Subclass Fragilariophycidae Round in Round, Crawford & Mann 1990, emend.
Subclass Bacillariophycidae D.G. Mann in Round, Crawford & Mann 1990, emend.
Others
Another systematic approach to classification was proposed in 1995, the Hoek, Mann and Jahns system. Previous versions of the Adl et al., 2019 classification appeared in Adl et al. 2005 and Adl et al. 2012, also in the chapter "Bacillariophyta" by Mann, Crawford & Round in the 2017 Handbook of the Protists edited by Archibald et al., in which some groups later named as formal taxa are listed under informal names (leptocylindrids, corethrids, melosirids, etc.).
References
Taxonomy classification | Taxonomy of diatoms | [
"Biology"
] | 3,660 | [
"Diatoms",
"Algae",
"Taxonomy classification",
"Taxonomy (biology)"
] |
65,237,686 | https://en.wikipedia.org/wiki/Pulsoconn | The Pulsoconn of Dr. Gerald Macaura (also called the Macaura blood circulator) was a device that, according to Macaura, should help women to loosen up and improve their blood circulation.
Macaura patented in 1902 a blood circulator in the USA. In 1904 he settled to the United Kingdom and patented the blood circulator again in 1904. with the patent number 13932, the number which is also on the Pulsocon. The Pulsoconn was operated by turning the handcrank on one side of the device, and depending on how fast the crank was rotated, it could produce up to 5000 vibrations per minute. The device could also be equipped with additional attachments of any form required and was presented as a cure for numerous illnesses. In 1911 he entered into a cooperation with the British Appliance Manufactural Co. Ltd. in Leeds, which then produced the Pulsocon. It had a lot of success throughout a long period of time.
Fraud claims
Macaura presented the Pulsoconn in 1911 at the Royal Albert Hall, London, which led to protests by medical students who opposed the devices alleged curative effects. During his stay in Paris in 1914, the French medics argued against the effectiveness of the curative effects of the Pulsocon and Gerald Macaura was condemned to three years in jail for fraud. He also was not a doctor as he claimed. He, though, had to stay only one year in prison, and during his stay in prison, he reportedly earned $75,000 from the sale of the Pulsocon.
The Pulsoconn was to be produced either until the 1920s or until the 1950s. After the Pulsoconn became known as a vibrator in movies like Gavroche et le pulsoconn from 1913, his success diminished amongst the well established society. In the 1950s, it was reported that the device was still used as a muscle stimulator in Irish gyms.
References
Massage devices
Vibrators
Medical devices | Pulsoconn | [
"Biology"
] | 420 | [
"Medical devices",
"Medical technology"
] |
65,239,613 | https://en.wikipedia.org/wiki/Copper%20%2864Cu%29%20oxodotreotide | {{DISPLAYTITLE:Copper (64Cu) oxodotreotide}}
Copper (64Cu) oxodotreotide or Copper Cu 64 dotatate, sold under the brand name Detectnet, is a radioactive diagnostic agent indicated for use with positron emission tomography (PET) for localization of somatostatin receptor positive neuroendocrine tumors (NETs) in adults.
Common side effects include nausea, vomiting and flushing.
It was approved for medical use in the United States in September 2020.
History
The U.S. Food and Drug Administration (FDA) approved copper 64Cu dotatate based on data from two trials that evaluated 175 adults.
Trial 1 evaluated adults, some of whom had known or suspected NETs and some of whom were healthy volunteers. The trial was conducted at one site in the United States (Houston, TX). Both groups received copper 64Cu dotatate and underwent PET scan imaging.
Trial 2 data came from the literature-reported trial of 112 adults, all of whom had history of NETs and underwent PET scan imaging with copper 64Cu dotatate. The trial was conducted at one site in Denmark. In both trials, copper 64Cu dotatate images were compared to either biopsy results or other images taken by different techniques to detect the sites of a tumor. The images were read as either positive or negative for presence of NETs by three independent image readers who did not know participant clinical information.
See also
Copper-64
DOTA-TATE
References
External links
Radiopharmaceuticals
Orphan drugs
DOTA (chelator) derivatives
Copper complexes | Copper (64Cu) oxodotreotide | [
"Chemistry"
] | 328 | [
"Chemicals in medicine",
"Radiopharmaceuticals",
"Medicinal radiochemistry"
] |
65,239,889 | https://en.wikipedia.org/wiki/Cas3 | Cas3 is an ATP-dependent single-strand DNA (ssDNA) translocase/helicase enzyme that degrades DNA as part of CRISPR based immunity.
Cas3 is a "signature" protein of class 1 CRISPR systems and functions in a complex known as CASCADE, with other cas genes and a targeting RNA to degrade viral DNA.
In April 2019 Cornell University researcher Ailong Ke published a paper in the journal Molecular Cell describing a new gene editing CRISPR system, CRISPR-Cas3 which can efficiently delete long swaths of DNA from a targeted site in the human genome. This ability is superior to that achieved with the more common CRISPR-Cas9 systems.
CONAN, a CRISPR based diagnostic approach was developed utilising Cas3
Structure and function
Thermophile Thermobifida fusca Cas3 is a four domain protein with an N-terminal HD-type nuclease domain, followed by two RecA-like domains forming a superfamily 2 helicase motif, then the Cas3 specific linker and C-terminal domain. Single stranded DNA is passed 3′-to-5′ from the helicase domain to the nuclease domain where it is hydrolysed.
References
Enzymes
Immune system
Prokaryote genes | Cas3 | [
"Biology"
] | 263 | [
"Immune system",
"Organ systems",
"Prokaryotes",
"Prokaryote genes"
] |
65,240,283 | https://en.wikipedia.org/wiki/Fault%20zone%20hydrogeology | Fault zone hydrogeology is the study of how brittlely deformed rocks alter fluid flows in different lithological settings, such as clastic, igneous and carbonate rocks. Fluid movements, that can be quantified as permeability, can be facilitated or impeded due to the existence of a fault zone. This is because different mechanisms that deform rocks can alter porosity and permeability within a fault zone. Fluids involved in a fault system generally are groundwater (fresh and marine waters) and hydrocarbons (Oil and Gas).
Take notice that permeability (k) and hydraulic conductivity (K) are used interchangeably in this article for simplified understanding
Architecture
A fault zone can be generally subdivided into two major sections, including a Fault Core (FC) and a Damage Zone (DZ) (Figure 1).
The fault core is surrounded by the damage zone. It has a measurable thickness which increases with fault throw and displacement, i.e. increasing deformations.
The damage zone envelopes the fault core irregularly in a 3D manner which can be meters to few hundred meters wide (perpendicular to the fault zone). Within a large fault system, multiple fault cores and damage zones can be found. Younger fault cores and damage zones can overlap the older ones.
Different processes can alter the permeability of the fault zone in the fault core and the damage zone will be discussed respectively in the next section. In general, the permeability of a damage zone is several orders of magnitude higher than that of a fault core as damage zones typically act as conduits (will be discussed in section 3). Within a damage zone, permeability decreases further away from a fault core.
Permeability classification
There are many classifications to group fault zones based on their permeability patterns. Some terms are interchangeable; while some have different subgroups. Most of expressions are listed in the following table for comparison. Dickerson's categorisation is commonly used and easier to understand in a broad range of studies.
The classification of a fault zone can change spatially and temporally. The fault core and damage zone can behave differently to accommodate the deformations. Moreover, the fault zone can be dynamic through time. Thus, the permeability patterns can change for short-term and long-term effects.
*K = Permeability/ Hydraulic Conductivity
*fz = fault zone
*hr = host rock = Undeformed rock surrounds the fault zones
Mechanisms (permeability)
Fault zone results from brittle deformation. Numerous mechanisms can vary the permeability of a fault zone. Some processes affect the permeability temporarily. These processes enhance the permeability for a certain period, and then reduce it later on: in this case, like seismic events, the permeability is not constant through time. Physical and chemical reactions are the major types of mechanisms. Different mechanisms can occur different in fault core and damage zone since the intensities of deformation they experience are different (Table 3).
*+ = more likely to occur at
Enhancing fault zone permeability
Deformation bands
The formation of a dilation band, in unconsolidated material, is the early result of applying extensional forces. Disaggregation of mineral fabric occurs along with the band, yet no offset is accommodated by the movement of grains (Figure 3). Further deformation causes offsets of mineral grains by rotation and sliding. This is called a shear band. The pore network is rearranged by granular movements (also called particulate flow), hence moderately enhance permeability. However, continuing deformation leads to the cataclasis of mineral grains which will further reduce permeability later on (section 3.2.3) (Figure 4).
Brecciation
Brecciation refers to the formation of angular, coarse-grained fragments embedded in a fine-grained matrix. As breccia (the rock experienced brecciation) is often non-cohesive, thus, permeability can be increased up to four or five orders of magnitude. However, the void space enlarged by brecciation will lead to further displacement along the fault zone by cementation, resulting in a strong permeability reduction (Figure 5).
Fracturing
Fractures propagate along a fault zone in direction responding to the stress applied. The enhancement of permeability is controlled by the density, orientation, length distribution, aperture, and connectivity of fractures. Even fracture with aperture of a 100-250 μm can still greatly influence fluid movement (Figure 6).
Reducing fault zone permeability
Sediment mixing
Sediments, typically from distinct formations, with different grain sizes, are mixed physically by deformation, resulting in a more poorly-sorted mixture. The pore space is filled by smaller grains, increasing tortuosity (mineral scale in this case) of fluid flow across the fault system.
Clay smears
Clay minerals are phyllo-silicate, in other words, with sheet-like structure. They are effective agents that block fluid flows across a fault zone. Clay smears, deformed layers of clay, that are developed along fault zone can act as a seal of hydrocarbon reservoir i.e. extremely low permeability that nearly prohibits all fluid flows (Figure 7).
Cataclasis
Cataclasis refers to pervasive brittle fracturing and comminution of grains. This mechanism becomes dominant at depth, greater than 1 km, and with larger grains. With increasing intensity of cataclasis, fault gouge, often with the presence of clay, is formed. The largest reduction occurs on the flows that are perpendicular to the band.
Enhancing and reducing fault zone permeability successively
Compaction and cementation
Compactions and cementation generally lead to permeability reduction by losing porosity. When a large region, which consist a fault zone, experience compaction and cementation, porosity loss in host rock (undeformed rock surrounding the fault zone) can be greater than that of fault zone rock. Hence, fluids are forced to flow through a fault zone.
Dissolution and precipitation
Solute carried by fluids can either enhance or reduce permeability by dissolution or precipitation (cementation). Which process takes place depends on geochemical conditions like rock composition, solute concentration, temperature, and so on. The changes in porosity dominantly control whether the fluid-rock interaction continues or slows down as a strong feedback reaction.
For example, minerals like carbonates, quartz, and feldspars are dissolved by the fluid-rock interactions due to enhanced permeability. Further introduction of fluids can either continuously dissolve or otherwise re-precipitate minerals in the fault core, and thus alters the permeability. Therefore, whether the feedback is positive or negative heavily depends on the geochemical conditions.
Seismic event
Earthquakes can either increase or decrease permeability along fault zones, depending on the hydrogeological settings. Recorded hot spring discharges show seismic waves dominantly enhance permeability, but reductions in discharge may also result occasionally. The timescale of the changes can be up to thousands of years. Hydraulic fracturing (fracking) requires increasing the interconnectedness of the pore space (in other words, permeability) of shale to allow the gas to flow through the rock, and very small deliberately induced seismic activity of magnitudes smaller than 1 are applied to enhance rock permeability.
Taking the Chile earthquake in 2017 as an example, the discharge of streamflow temporally increased six times indicates a sixfold enhancement in permeability along the fault zone. Yet, seismic-induced effects are temporary that normally last for months, for Chile's case, it lasted for one and a half months which gradually decreased back to original discharge.
Mechanisms (porosity)
Porosity (φ) directly reflects the specific storage of rock. And brittle formation alters the pores by different mechanisms. If the pores are deformed and connected together, the permeability of rock enhances. On the other hand, if the deformed pores disconnect with each other, the permeability of rock in this case reduces.
Pore types
Enhancing porosity
Dissolution
The mineral grains can be dissolved when there is fluid flow. The spaces originally occupied by the minerals will be spare as voids, increasing the porosity of rock. The minerals that are usually dissolved are feldspar, calcite and quartz. Grain dissolution pores results from this process can enhance porosity.
Reducing porosity
Cataclasis, fracturing and brecciation
The mineral grains are broken up into smaller pieces by faulting event. Those smaller fragments will re-organise and further be compacted to form smaller pore spaces. These processes create intragranular fracture pores and transgranular fracture pores.
Important to be aware is that reducing porosity does not equal to reduction in permeability. Fracturing, bracciation and initial stage of cataclasis can connect pore spaces by cracks and dilation bands, increasing permeability.
Precipitation
The mineral grains can be precipitated when there is fluid flow. The voids in the rocks can be occupied by precipitation of mineral grains. The minerals fill the voids and hence, reducing the porosity. Overgrowth, precipitation around an existing mineral grain, of quartz are common. And overgrown minerals infill pre-existing pores, reducing porosity.
Clay deposition
Clay minerals are phyllo-silicate, in other words, with sheet-like structure. They are effective agents that block fluid flows. Kaolinite which is altered from potassium feldspar with the presence of water is a common mineral that fills pore spaces. Precipitation and infiltration only affect materials on shallow depth, hence, more clay materials infill pore spaces when they are closer to the surface. Yet, development of a fault zone introduces fluid to flow deeper. Thus, this facilitates clay deposition at depth, reducing porosity.
Lithological effects
Lithology has a dominant effect on controlling which mechanisms would take place along a fault zone, hence, changing the porosity and permeability.
*↑ = mechanism that enhance permeability
*↓ = mechanism that reduce permeability
Fault type effects
All faults can be classified into three types. They are normal fault, reverse fault (thrust fault) and strike-slip fault. These different faulting behaviours accommodate the displacement in distinct structural ways.
The differences in faulting motions might favour or disfavour certain permeability altering mechanisms to occur. However, the main controlling factor of the permeability is the rock type. Since the characteristics of rock control how a fault zone can be developed and how fluids can move. For instance, sandstone generally has a higher porosity than that of shale. A deformed sandstone in three different faulting systems should have a higher specific storage, hence permeability, than that of shale. Similar example like the strength (resistance to deform) also significantly depends on rock types instead of fault types. Thus, the geological features of rock involved in a fault zone is a more dominated factor.
On the other hand, the type of fault might not be a dominant factor but the intensity of deformation is. The higher intensity of stresses applied to the rock, the more intense the rock will be deformed. The rock will experience a greater permeability changing event. Thus, the amount of stress applied matters.
Equally important is that identifying the permeability category of the fault zones (barriers, barrier-conduits and conduits) is the main scope of study. In other words, how the fault zones behave when there are fluids pass through.
Studying approaches and methods
Surface and subsurface test
The studies of fault zones are recognised in the discipline of Structural Geology as it involves how rocks were deformed; while investigations of fluid movements are grouped in the field of Hydrology. There are mainly two types of methods used to examine the fault zone by structural geologists and hydrologists (Figure 7).
In situ test includes obtaining data from boreholes, drill cores, and tunnel projects. Normally the existence of a fault zone is found as different hydraulic properties are measured across it as fault zones are rarely drilled through (except for tunnel projects) (Figure 8).
The hydraulic properties of rocks are either obtained directly from outcrop samples or shallow probe holes/ trial pits, then the predictions of fault structure are made for the rocks at depth (Figure 8).
Example of a subsurface test
An example of a large-scale aquifer test conducted by Hadley (2020), the author used 5 wells aligned perpendicular to the Sandwich Fault Zone in the US, and the drawdowns as well as the recovery rates of water levels in every well were observed. From the evidence that the recovery rates are slower for the wells closer to the fault zone, it is suggested that the fault zone acts as a barrier for northward groundwater movement, affecting freshwater supply in the north.
Example of a surface test
From an outcrop study of the Zuccale Fault in Italy by Musumeci (2015), the surface outcrop findings and cross-cutting relationship are used to determine the number and mechanism of deformational events happened in the region. Moreover, the presences of breccias and cataclasites, that formed under brittle deformation, suggest that there was an initial stage of permeability increase, promoting an influx of -rich hydrous fluids. The fluids triggered low-grade metamorphism and dissolution-and-precipitation (i.e. pressure-solution) in mineral scale that shaped a foliated fault core, hence, enhancing the sealing effect significantly.
Other methods
Geophysics
Underground fluids, particularly groundwater, create anomalies for superconducting gravity data which help study the fault zone at depth. The method combines gravitational data and groundwater conditions to determine not only the permeability of a fault zone but also whether the fault zone is active or not.
Geochemistry
The geochemistry conditions of mineral fluids, water or gases, can be used to determine the existence of a fault zone by comparing the geochemistry of fluids' source, given that the conditions of aquifers are known. The fluids can be categorized by the concentrations of common solutes like total dissolved solids (TDS), Mg-Ca-Na/K phase, SO4-HCO3-Cl phase, and other dissolved trace elements.
Existing biases
The selection of an appropriate studying approach(es) is essential as there are biases existed when determining the fault zone permeability structure.
In crystalline rocks, the subsurface-focused investigations favor the discoveries of a conduit fault zone pattern; while the surface methods favor a combined barrier-conduit fault zone structure. The same biases, to a lesser extend, exist in sedimentary rock as well.
The biases can be related to the differences in studying scale. For structural geologists, it is very difficult to conduct outcrop study over a vast region; likewise, for hydrologists, it is expensive and ineffective to shorten borehole intervals for testing.
Economic geology
It is economically worth studying the complex system, especially for arid/ semi-arid regions, where freshwater resources are limited, and potential areas with hydrocarbon storages. Further research on the fault zone, the result of deformation, gave insights on the interactions between earthquakes and hydrothermal fluids along fault zone. Moreover, hydrothermal fluids associated with the fault zone also provide information on how ore deposits accumulated.
Artificial hydrocarbon reservoirs
Carbon sequestration is a modern method dealing with atmospheric carbon. One of the methods is pumping atmospheric carbon to specific depleted oil and gas reservoirs at depth. However, the presence of a fault zone act as either a seal or a conduit, affecting the efficiency of hydrocarbon formation.
Micro-fractures that cut along the sealing unit and the reservoir rock can greatly affect the hydrocarbon migration. The deformation band blocks the lateral (horizontal) flow of and the sealing unit keeps the from vertical migration (Gif 1). The propagation of a micro-fracture that cuts through a sealing unit, instead of having a deformation band within the sealing unit, facilitates upward migration (Gif 2). This allows fluid migrations from one reservoir to another. In this case, the deformation band still does not facilitate lateral (horizontal) fluid flow. This might lead to the loss of injected atmospheric carbon, lowering the efficiency of carbon sequestration.
A fault zone that displaces sealing units and reservoir rocks can act as a conduit for hydrocarbon migration. The fault zone itself has higher storage capacity (specific capacity) than that of the reservoir rocks, therefore, before the migration to other units, the fault zone has to be fully filled (Gif 3). This can slower and concentrate the fluid migration. The fault zone facilitates vertical downwards movement of due to its buoyancy and piezometric head differences, i.e. pressure/ hydraulic head is greater at a higher elevation, which helps store at depth.
Seismic-induced ore deposits
Regions that are or were seismic active and with the presence of fault zones might indicate there are ore deposits.
A case study in Nevada, US by Howald (2015) studied how seismic-induced fluids accumulate mineral deposits, namely sinter and gold, along spaces provided by a fault zone. Two separate seismic events were identified and dated by oxygen isotopic concentrations, followed by episodes of the upward hydrothermal fluid migrations through permeable normal fault zone. Mineralization started to take place when these hot silica-rich hydrothermal fluids met the cool meteoric water infiltrated along the fault zone until the convective flow system was shut down. In order to deposit minerals, seismic events that bring hydrothermal fluids are not the only dominant factor, the permeability of the fault zone also has to be sufficient for permitting fluid flows.
Another example taken from Sheldon (2005) also shows that development of fault zone, in this case by strike-slip faulting, facilitates mineralization. Sudden dilation happened along with strike-slip events increases the porosity and permeability along the fault zone. Larger displacement will lead to greater increase in porosity. If the faulting event cut through a sealing unit which seals a confined aquifer of over-pressured fluids, the fluids can rise through the fault zone. Then mineralization will take place along the fault zone by pressure solution, reducing the porosity of the fault zone. The fluid flow channel along the fault zone will be shut down when the pores are almost occupied by newly precipitated ore minerals. Multiple seismic events have to be occurred to form these economic ore deposit with vein structure.
See also
Carbon sequestration
Fault (geology)
Fault breccia
Fault gouge
Hydraulic conductivity
Hydrocarbons
Hydrology
Hydrogeology
Petroleum
Permeability
Structural geology
References
Hydrogeology
Faults (geology)
Porous media
Soil mechanics | Fault zone hydrogeology | [
"Physics",
"Materials_science",
"Engineering",
"Environmental_science"
] | 3,880 | [
"Hydrology",
"Applied and interdisciplinary physics",
"Porous media",
"Soil mechanics",
"Materials science",
"Hydrogeology"
] |
65,241,786 | https://en.wikipedia.org/wiki/Front%20electric%20sustainer | Front electric sustainer (FES) is a propulsion system for gliders that uses an electric motor powered by batteries and a foldable propeller. It is produced by LZ Design d.o.o. in Logatec, Slovenia.
The system uses a 22 kW compact outrunner brushless DC electric motor located in the nose of the sailplane. Power is provided by two lithium-ion battery packs. Lighter gliders are able to self-launch with FES. Heavier gliders can use it as a sustainer system, i.e. climb and cruise sufficiently high and far to avoid an out-landing. Although gliders with FES have a shorter range (70–100 km) under power than gliders with two-stroke gasoline sustainer engines (10 litres at 8.5 L/h at 100 km/h = 120 km) or jet sustaining engines (150–200 km), the electric motor can be expected to start reliably provided there is sufficient energy in the batteries.
The one-metre diameter propeller is made of carbon fibre and folds across the nose. It opens using centrifugal force when rotation starts. Each propeller blade weighs 260 grams. They are slightly bent to take the shape of the front surface of the fuselage of each type of glider to which they are fitted.
Unlike some electric gliders such as the Lange Antares and Schleicher AS 34Me, the batteries can be removed from the glider for charging off-site. No power supply is needed near the glider itself. The two battery packs each contain 28 Kokam lithium polymer cells. The cells are wired in serial and operates at a voltage range of 90–116V. The two packs contain a total of 4.2 kW⋅h of energy. Each pack weighs 15.7 kg and are mounted in a reinforced area in the fuselage behind the wings. This configuration balances the weight of the motor and propeller. Reinforced carrying cases are used to transport the battery packs to a location where they can be charged.
More than 240 gliders of eleven different types, from seven manufacturers, are already equipped with this system.
Schempp-Hirth Ventus 3 and its predecessor Schempp-Hirth Ventus 2
Schempp-Hirth Discus 2
Schempp-Hirth Duo Discus
DG Flugzeugbau DG-1000
Rolladen-Schneider LS8
LAK-17 and Mini-LAK
HPH 304
Diana Sailplanes Diana
Alisport Silent 2
Albastar AS
References
External links
LZ Design web-site
Electric motors
Slovenian brands
Electric aircraft | Front electric sustainer | [
"Technology",
"Engineering"
] | 527 | [
"Electrical engineering",
"Engines",
"Electric motors"
] |
65,242,143 | https://en.wikipedia.org/wiki/Biocuration | Biocuration is the field of life sciences dedicated to organizing biomedical data, information and knowledge into structured formats, such as spreadsheets, tables and knowledge graphs. The biocuration of biomedical knowledge is made possible by the cooperative work of biocurators, software developers and bioinformaticians and is at the base of the work of biological databases.
Biocuration as a profession
A biocurator is a professional scientist who curates, collects, annotates, and validates information that is disseminated by biological and model organism databases. It is a new profession, with the first mentions in the scientific literature dating of 2006 in the context of the work in databases like the Immune Epitope Database and Analysis Resource. Biocurators usually are PhD-level with a mix of experiences in wet lab and computational representations of knowledge (e.g. via ontologies).
The role of a biocurator encompasses quality control of primary biological research data intended for publication, extracting and organizing data from original scientific literature, and describing the data with standard annotation protocols and vocabularies that enable powerful queries and biological database interoperability. Biocurators communicate with researchers to ensure the accuracy of curated information and to foster data exchanges with research laboratories.
Biocurators are present in diverse research environments, but may not self-identify as biocurators. Projects such as ELIXIR (the European life-sciences Infrastructure for biological Information) and GOBLET (Global Organization for Bioinformatics Learning, Education and Training) promote training and support biocuration as a career path.
In 2011, biocuration was already recognized as a profession, but there were no formal degree courses to prepare curators for biological data in a targeted fashion. With the growth of the field, the University of Cambridge and the EMBL-EBI started to jointly offer a Postgraduate Certificate in Biocuration, considered as a step towards recognising biocuration as a discipline on its own. There is a perceived increase in demand of biocuration, and a need for additional biocuration training by graduate programs.
Organizations that employ biocurators, like Clinical Genome Resource (ClinGen), often provide specialized materials and training for biocuration.
Biological knowledgebases
The role of biocurators is best known among the field of biological knowledgebases. Such databases, like UniProt and PDB rely on professional biocurators to organize information. Among other things, biocurators work to improve the data quality, for example, by merging duplicated entries.
An important part of those knowledgebases are model organisms databases, which rely on biocurators to curate information regarding organisms of particular kinds. Some notable examples of model organism databases are FlyBase, PomBase, and ZFIN, dedicated to curate information about Drosophila, Schizosaccharomyces pombe and zebrafish respectively.
Curation and annotation
Biocuration is the integration of biological information into on-line databases in a semantically standardized way, using appropriate unique traceable identifiers, and providing necessary metadata including source and provenance.
Ontologies, controlled vocabularies and standard names
Biocurators commonly employ and take part in the creation and development of shared biomedical ontologies: structured, controlled vocabularies that encompass many biological and medical knowledge domains, such as the Open Biomedical Ontologies. These domains include genomics and proteomics, anatomy, animal and plant development, biochemistry, metabolic pathways, taxonomic classification, and mutant phenotypes. Given the variety of existing ontologies, there are guidelines that orient researchers on how to choose a suitable one.
The Unified Medical Language System is one such systems that integrates and distributes millions of terms used in the life sciences domain.
Biocurators enforce the consistent use of gene nomenclature guidelines and participate in the genetic nomenclature committees of various model organisms, often in collaboration with the HUGO Gene Nomenclature Committee (HGNC). They also enforce other nomenclature guidelines like those provided by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB), one example of which is the Enzyme Commission EC number.
More generally, the use of persistent identifiers is praised by the community, so to improve clarity and facilitate knowledge
DNA annotation
In genome annotation for example, the identifiers defined by the ontologists and consortia are used to describe parts of the genome. For example, the gene ontology (GO) curates terms for biological processes, which are used to describe what we know about specific genes.
Text annotation
As of 2021, life sciences communication is still done primarily via free natural languages, like English or German, which hold a degree of ambiguity and make it hard to connect knowledge. So, besides annotating biological sequences, biocurators also annotate texts, linking words to unique identifiers. This aids in disambiguation, clarifying the meaning intended, and making the texts processable by computers. One application of text annotation is to specify the exact gene a scientist is referring to.
Publicly available text annotations make it possible to biologists to take further advantage of biomedical text. The Europe PMC has an Application Programming Interface which centralizes text annotations from a variety of sources and make them available in a Graphic User Interface called SciLite. The PubTator Central also provides annotations, but is fully based on computerized text-mining and does not provide a user interface. There are also programs that allow users to manually annotate the biomedical texts they are interested, such as the ezTag system.
Variant Curation
A type of biocuration within the field of medical genetics, variant curation is a process for assessment of genetic changes according to the likelihood that they may cause disease. This is an evidence-based process that uses data from a multitude of sources. These sources can include population data, computational data, functional data, segregation data, de novo data, allelic data, among others. It is a collaborative process that can be automated, however manual curation is considered to be the gold standard.
There is no single standardised process of variant curation; different researchers and organisations use different variant curation processes. However, a set of internationally accepted standards and guidelines for the interpretation of genetic variants have been jointly developed by the American College of Medical Genetics and the Association for Molecular Pathology. These are known as the ACMG/AMP guidelines. These guidelines provide a framework for classifying genetic variants as “pathogenic”, “likely pathogenic”, “uncertain significance”, “likely benign” or “benign”, in order from most likely to cause disease to least likely to cause disease. The guidelines also list various levels of evidence ranging from very strong, strong, moderate or supporting. The combination of types of evidence found, and the levels in which those pieces of evidence exist, allows for each variant to be classified along the scale from "pathogenic" to "benign".
International Society for Biocuration (ISB)
The International Society for Biocuration (ISB) is a non-profit organisation "promotes the field of biocuration and provides a forum for information exchange through meetings and workshops." It has grown from the International Biocuration Conferences and founded in early 2009.
The ISB offers the Biocuration Career Award to biocurators in the community: the Biocurator Career Award (given annually) and the ISB Award for Exceptional Contributions to Biocuration (given biannually).
The official journal of the ISB, Database, is a venue specialized in articles about databases and biocuration.
Community curation
Traditionally, biocuration has been done by dedicated experts, which integrate data into databases. Community curation has emerged as a promising approach to improve the dissemination of knowledge from published data and provide a cost-effective way to improve the scalability of biocuration. In some cases, community help is leveraged in jamborees that introduce domain experts to curation tasks, carried during the event, while others rely on asynchronous contributions of experts and non-experts.
Biological databases
Several biological databases include author contributions in their functional curation strategy to some extent, which may range from associating gene identifiers with publications or free-text, to more structured and detailed annotation of sequences and functional data, outputting curation to the same standards as professional biocurators. Most community curation at Model Organism Databases involves annotation by original authors of published research (first-pass annotation) to effectively obtain accurate identifiers for objects to be curated, or identify data-types for detailed curation. For example:
WormBase successfully solicits first-pass annotation from users and has integrated author curation with the micropublication process. WormBase also integrates text-mining to its platform, providing suggestions to community curators.
FlyBase sends email requests to authors of new publications, inviting them to list the genes and data types described via an online tool and has also mobilized the community to write gene summary paragraphs.
Other databases, such as PomBase, rely on publication authors to submit highly detailed, ontology-based annotations for their publications, and meta-data associated with genome-wide data-sets using controlled vocabularies. A web-based tool Canto; was developed to facilitate community submissions. Since Canto is freely available, generic and highly configurable, it has been adopted by other projects. Curation is subjected to review by professional curators resulting in high quality in-depth curation of all molecular data-types.
The widely used UniProt knowledgebase has also a community curation mechanism that allows researchers to add information about proteins.
Wiki-style resources
Bio-wikis rely on their communities to provide content and a series of wiki-style resources are available for biocuration. AuthorReward, for example, is an extension to MediaWiki that quantifies researchers' contributions to biology wikis. RiceWiki was an example of a wiki-based database for community curation of rice genes equipped with AuthorReward. CAZypedia is another such wiki for community biocuration of information on carbohydrate-active enzymes (CAZys).
The WikiProteins/WikiProfessional was a project to semantically organize biological data led by Barend Mons. The 2007 project had direct contributions of Jimmy Wales, Wikipedia co-founder, and took Wikidata as an inspiration. A currently active project that runs on an adaptation of mediawiki software is WikiPathways, which crowdsources information about biological pathways.
Wikipedia
There is some overlap between the work of biocurators and Wikipedia, with boundaries between scientific databases and Wikipedia becoming increasingly blurred. Databases like Rfam and the Protein Data Bank for example make heavy use of Wikipedia and its editors to curate information. However, most databases offer highly structured data that is searchable in complex combinations, which is usually not possible on Wikipedia, although Wikidata aims at solving this problem to some extent.
The Gene Wiki project used Wikipedia for collaborative curation of thousands of genes and gene products, such as titin and insulin. Several projects also employ Wikipedia as a platform for curation of medical information.
One other way that Wikipedia is used for biocuration is via its list articles. For example, the Comprehensive Antibiotic Resistance Database integrates its assessment of databases about antibiotic resistance to a particular Wikipedia list.
Wikidata
The Wikimedia knowledge base Wikidata is increasingly being used by the biocuration community as an integrative repository across life sciences. Wikidata is being seen by some as an alternative with better prospects of maintenance and interoperability than smaller independent biological knowledge bases.
Wikidata has been used to curate information on SARS-CoV-2 and the COVID-19 pandemic and by the Gene Wiki project to curate information about genes. Data from biocuration on Wikidata is reused on external resources via SPARQL queries. Some projects use curation via Wikidata as a path to improve life-sciences information on Wikipedia.
Gamified resources
An approach to involve the crowd in biocuration is via gamified platforms that use game design principles to boost engagement. A few examples are:
Mark2Cure, a gamified platform for community curation of biomedical abstracts
Cochrane Crowd, a platform by Cochrane for curation of clinical trials and to categorize and summarize biomedical literature.
CIViC, a portal for annotation of genomic variants related to cancer which tracks scores and keeps leaderboards.
APICURON, a database to credit and acknowledge the work of biocurators, that collects and aggregates biocuration events from third party resources and generates achievements and leaderboards.
Computational text mining for curation
Natural-language processing and text mining technologies can help biocurators to extract of information for manual curation. Text mining can scale curation efforts, supporting the identification of gene names, for example, as well as for partially inferring ontologies. The conversion of unstructured assertions to structured information makes use of techniques like named entity recognition and parsing of dependencies. Text-mining of biomedical concepts faces challenges regarding variations in reporting, and the community is working to increase the machine-readability of articles.
During the COVID-19 pandemic, biomedical text mining was heavily used to cope with the large amount of published scientific research about the topic (over 50.000 articles).
The popular NLP python package SpaCy has a modification for biomedical texts, SciSpaCy, which is maintained by the Allen Institute for AI.
Among the challenges for text-mining applied to biocuration is the difficulty of accessing full texts of biomedical articles due to pay wall, linking the challenges of biocuration to those of the open-access movement.
A complementary approach to biocuration via text mining involves applying optical character recognition to biomedical figures, coupled to automatic annotation algorithms. This has been used to extract gene information from pathway figures, for example.
Suggestions to improve the written text to facilitate annotations range from using controlled natural languages to providing clear association of concepts (such as genes and proteins) with the particular species of interest.
While challenges remain, text-mining is already an integral part of the workflow of biocuration in several biological knowledgebases.
Biocreative challenges
The BioCreAtivE (Critical Assessment of Information Extraction systems in Biology) Challenge is a community-wide effort to develop and evaluate text mining and information extraction systems for the life sciences. The challenge was first launched in 2004 and has since become an important event in the biocuration and bioinformatics communities. The main goal of the challenge is to foster the development of advanced computational tools that can effectively extract information from the vast amount of biological data available.
The BioCreative Challenge is organized into several subtasks that cover various aspects of text mining and information extraction in the life sciences. These subtasks include gene normalization, relation extraction, entity recognition, and document classification. Participants in the challenge are provided with a set of annotated data to develop and test their systems, and their performance is evaluated based on various metrics, such as precision, recall, and F-score.
The BioCreative Challenge has led to the development of many innovative text mining and information extraction systems that have greatly improved the efficiency and accuracy of biocuration efforts. These systems have been integrated into many biocuration pipelines and have helped to speed up the curation process and enhance the quality of curated data.
See also
AgBase
Biological database
Digital curation
International Society for Biocuration
Model Organism Database
OBO Foundry
References
External links
International Society for Biocuration
Biocreative
Online course on biocuration at EMBL-EBI
Biological databases | Biocuration | [
"Biology"
] | 3,295 | [
"Bioinformatics",
"Biological databases"
] |
65,243,377 | https://en.wikipedia.org/wiki/Allotropes%20of%20arsenic | Arsenic in the solid state can be found as gray, black, or yellow allotropes. These various forms feature diverse structural motifs, with yellow arsenic enabling the widest range of reactivity. In particular, reaction of yellow arsenic with main group and transition metal elements results in compounds with wide-ranging structural motifs, with butterfly, sandwich and realgar-type moieties featuring most prominently.
Gray arsenic
Gray arsenic, also called grey arsenic or metallic arsenic, is the most stable allotrope of the element at room temperature, and as such is its most common form. This soft, brittle allotrope of arsenic has a steel gray, metallic color, and is a good conductor. The rhombohedral form of this allotrope is analogous to the phosphorus allotrope black phosphorus. In its α-form, As6 rings in chair confirmations are condensed into packed layers lying perpendicular to the crystallographic c axis. Within each layer, the vicinal As-As bond distances are 2.517 Å, while the layer-to-layer As-As bond distances are 3.120 Å. The overall structure displays a distorted octahedral geometry, resulting in the largely metallic properties of this allotrope. Upon sublimation at 616 °C, the gas phase arsenic molecules lose this packing arrangement and form small clusters of As4, As2, and As, though As4 is by far the most abundant in this phase. If these vapors are condensed swiftly onto a cold surface (<200 K), solid yellow arsenic (As4) results due to the lack of energy required to form the rhombohedral gray arsenic lattice. Conversely, condensation of arsenic vapors onto a heated surface generates amorphous black arsenic. The crystalline form of black arsenic can also be isolated, and the amorphous form can be annealed to return to the metallic gray arsenic form. Yellow arsenic can also be returned to the gray allotrope in a facile manner through application of light or by returning the molecule to room temperature.
Reactivity
Relatively few in-situ reactions have been reported involving gray arsenic due to its low solubility, although it reacts in air to form gaseous As2O3 . Two examples of the reactivity of gray arsenic towards transition metals are known. In these reactions, cyclopentadienyl complexes of molybdenum, tungsten and chromium proceed via loss of carbon monoxide to react with gray arsenic and form mono-, di-, and triarsenic compounds.
Black arsenic
Black, or amorphous arsenic (chemical formula Asn) is synthesized first through the sublimation of gray arsenic followed by condensation onto a heated surface. This structure is thought to be the arsenic analogue of red phosphorus. The structure of black arsenic in its crystalline phase, while not synthesized in its pure form, is by extension analogous to black phosphorus, and takes on an orthorhombic structure built from As6 rings. Black arsenic has as-yet been synthesized only in the presence of atomic impurities including mercury,
phosphorus, and oxygen, though a pure form of black arsenic was found in the Copiapó region of Chile. Mechanical exfoliation of the mineral found in Chilean caves, arsenolamprite, revealed a molecular structure with high in-phase anisotropy and potential as a semiconducting material.
Yellow arsenic
Rapid condensation of arsenic vapors on to a cold surface results in the formation of yellow arsenic (As4), consisting of four arsenic atoms arranged in a tetrahedral geometry analogous to white phosphorus. Though it is the only soluble form of arsenic known, yellow arsenic is metastable: at room temperature, or in the presence of light, the structure quickly decomposes to adopt the lower-energy configuration of gray arsenic. For this reason, extensive care is required to maintain yellow arsenic in a state suitable for reaction, including rigorous exclusion of light and maintenance of temperatures below −80 °C. Yellow arsenic is the allotrope most suited for reactivity studies, due to its solubility (low, but comparatively large relative to the metallic allotrope) and molecular nature. In comparison to its lighter congener, phosphorus, the reactivity of arsenic is relatively underexplored. Research investigating reactions with arsenic are primarily concerned with the activation of main group and transition metal compounds; in the case of transition metal complexes, As4 has demonstrated competent reactivity across the d-block of the periodic table.
Reactivity towards main group compounds
The first activation of a main group compound by yellow arsenic was reported in 1992 by West and coworkers, involving the reaction of As4 with a disilene compound, tetramesityldisilene, to generate a mixture of compounds including a butterfly structural motif of bridging arsenic atoms. Notably, the product mixture obtained in this reaction differs from the analogous reaction with P4 that produces the butterfly compound alone, highlighting that the reactivity of yellow arsenic and white phosphorus cannot be considered identical. The first organo-substituted As4 compound was produced by Scheer and coworkers in 2016 via reaction with the CpPEt radical. Analogous to the butterfly compound obtained by the West group, the product obtained in this reaction featured a bridging As4 motif that reversibly returned As4 and the parent radical in the presence of light or heat. This characteristic makes the CpPEt2As4 complex a uniquely suitable "storage" molecule for yellow arsenic, as it is stable when stored at room temperature in the dark, but can release As4 in thermal or photochemical solutions.
Other reactions of main group compounds with yellow arsenic have been shown to involve units of arsenic with more than four atoms. In reaction with the silylene compound [PhC(NtBu)2SiN(SiMe3)2], an aggregation of As4 was observed to form a cage compound of ten arsenic atoms, including a seven-membered arsenic ring at its center.
Reactivity towards transition metal compounds
Group 4 and 5 metals
Among the early (group 4 and 5) transition metal elements, few examples of arsenic activation has been reported to date. Carbon monoxide complexes of zirconium with derivatized cyclopentadienyl ligands were shown to react with yellow arsenic in boiling xylene to release CO and bind the As4 moiety in η1:1-fashion. Trace amounts of a zirconium dimer bridged by a (μ,η2:2:1-As5)-moiety were also reported in this study, which described the complexes as possible reagents for As4 transfer. In group 5, arsenic activation has been more widely explored, with complexes of both niobium and tantalum known. Investigation of the electron density topology in a phosphorus/arsenic/niobium-containing system demonstrated the unique η2-bonding configuration in these complexes, in which an arsenic-phosphorus double bond binds side-on to a niobium center.
Group 6 metals
Reactions of yellow arsenic with the group 6 transition metals largely proceed through thermolytic carbon monoxide elimination in chromium and molybdenum carbonyl complexes. Notable examples include the formation of triple-decker complexes [(CpRMo)2(μ,η6-As6)] and [{CpRCr}2(μ,η5-As5)] via reaction of the corresponding molybdenum and chromium dimers with yellow arsenic. These remarkable structures feature three planar-rings arranged in parallel fashion to result in an idealized D5h point group for the chromium complex. Both of these reactions necessitate harsh reaction conditions like boiling xylene to overcome the high barriers to activation of As4. Conversely, utilization of more sterically demanding ligands on the metal center enabled reactions in milder conditions with molybdenum and chromium. Cummins' Mo(N(tBu)Ar)3 catalyst, also known to split the N-N triple bond in dinitrogen, reacts with yellow arsenic to form a terminal arsenic moiety triple-bonded to the metal center - one of only several compounds known to contain a terminal arsenic atom. Complexes with metal-metal multiple bonds also enable mild As4 activation parameter. A chromium-chromium quintuply-bonded species reported by Kempe reacts with yellow arsenic to form a crown complex in which the four arsenic atoms form an approximately tetrahedral structure, with each chromium atom bonding to three arsenic atoms.
Group 8 and 9 metals
The metals of groups 8 and 9 feature the most extensive library of reactivity with yellow arsenic documented in the scientific literature, with particular focus on reactions of iron and cobalt complexes with As4. Much like the chromium and molybdenum sandwich complexes, (CpRFe(CO)2]2 complexes of iron react with yellow arsenic to produce analogous bimetallic products featuring "triple-decker" geometry. These reports also detail the isolation of a key intermediate, pentaarsaferrocene ([CpRFe(μ5-As5)]). This intermediate, isolobal to ferrocene, replaces one of the cyclopentadienyl ligands with a cyclic As5 ligand that features As-As bond lengths of 2.312 Å (in line with delocalized As-As double bonds). This "sandwich-forming" reactivity can be meaningfully tuned by introducing bulkier ligands. Modifying the cyclopentadienyl groups with much bulkier derivatives produces a vastly different set of products. First, a butterfly complex with a central As4 unit is formed. Irradiation with light leads to further CO elimination and the formation of a bridged butterfly complex, which then rearranges into a unique complex featuring a central As8 moiety. This ligand, formally tetraanionic, forms an eight-membered ring bridging four iron atoms in total.
Much of the same reactivity, including formation of butterfly and sandwich compounds, has been described for cobalt complexes in the presence of yellow arsenic. Beyond these compounds, the history of reactivity of cobalt and yellow arsenic dates back to 1978, when Sacconi and coworkers reported the reaction of cobalt tetrafluoroborate and yellow arsenic in the presence of 1,1,1-tris(diphenylphosphinomethyl)ethane. The resulting complex features a cyclic As3 moiety bridging two cobalt centers, of which the former is assigned formally as a 3π-electron system. The reaction of [Cp*Co(CO)]2 dimer with yellow arsenic was shown by Scherer et al. to produce a wide variety of isolable products, featuring a mixture of linking arsenic moieties including cyclobutane-like and butterfly type complexes. Analogous reactions with rhodium complexes are also known.
Group 10 and 11 metals
Among the group 10 and 11 elements, nickel and copper feature most prominently in literature reactions with yellow arsenic. Nickel tetrafluoroborate salts react analogously to cobalt complexes in the presence of triphos to form a sandwich structure with a central cyclic As3 moiety. Much like iron, the reaction of nickel cyclopentadienyl carbonyl complexes with As4 yields a variety of bi- and multi-metallic products depending on the size of the attending ligands, though the nature and geometric structure of these compounds differ from those observed with iron. These include trimers with bridging As4 and As5 moieties in cubane structural arrangements when smaller Cp ligands are employed, and distorted hexagonal prism complexes with two nickel fragments and four arsenic atoms when bulkier Cp groups are introduced.
The reaction of the copper complex [L2Cu(NCMe)] (L2 = [{N(C6H3iPr2-2,6)C(Me)}2CH]) with yellow arsenic yields the As4-bridged dimer [{L2Cu}2- (μ,η2:2-As4)]. The four-atom arsenic moiety in this complex was deemed to be "intact" yellow arsenic through the use of density functional theory calculations determining the change in bond critical points between the free and bound arsenic molecules. Specifically, only a small shift was observed in the bond critical points between arsenic atoms involved in binding to copper; the remaining bond critical points were very similar to free yellow arsenic.
See also
Allotropes of phosphorus
References
Arsenic
Arsenic | Allotropes of arsenic | [
"Physics",
"Chemistry"
] | 2,599 | [
"Periodic table",
"Properties of chemical elements",
"Allotropes",
"Materials",
"Matter"
] |
65,243,470 | https://en.wikipedia.org/wiki/Nagamori%20Awards | The Nagamori Award is an international award given by Nagamori Foundation of Kyoto, Japan. The award is to recognize outstanding researchers and engineers working on electrical and electronics engineering, especially related to motors, power generation, actuators, and energy related topics.
History
The awarded is founded by Shigenobu Nagamori in 2014, with the purpose of recognizing global researchers and engineers who have made outstanding and innovative technological advances in the area of electrical motors and power generation.
Awards details
The award is made annually to outstanding early to mid-career researchers and engineers. There will be six awards given annually, with one of the awards named as the Grand Nagamori award. The prize money of two million yen is awarded to each regular Nagamori award while the grand award comes with a cash prize of five million yen. An award ceremony is held in Kyoto, Japan around September each year, where winners will be present to receive their prizes.
Recent winners
The following are some of the recent winners.
References
International awards
Engineering awards
Electrical and electronic engineering awards
Japanese science and technology awards | Nagamori Awards | [
"Technology",
"Engineering"
] | 213 | [
"Electrical and electronic engineering awards",
"International science and technology awards",
"Engineering awards",
"Electronic engineering",
"Science and technology awards",
"Electrical engineering"
] |
61,486,154 | https://en.wikipedia.org/wiki/C16H14N2O2 | {{DISPLAYTITLE:C16H14N2O2}}
The molecular formula C16H14N2O2 (molar mass: 266.295 g/mol) may refer to:
Doliracetam
Methoxyqualone
Miroprofen
URB754
Molecular formulas | C16H14N2O2 | [
"Physics",
"Chemistry"
] | 65 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,486,283 | https://en.wikipedia.org/wiki/NGC%201374 | NGC 1374 is a low-luminosity elliptical galaxy in the southern constellation Fornax. It was discovered by John Herschel on November 29, 1837.
Location
It is at a distance of 59 million light years. The galaxy may form a pair with another nearby galaxy, NGC 1375, but this is uncertain based on the estimated distance of NGC 1375. It is a member of the Fornax Cluster, a cluster of 200 galaxies, and it is positioned near the center of the cluster and central galaxy NGC 1399, while the closest galaxy after NGC 1375, outside the pair, is NGC 1373. NGC 1374's size on the night sky is 2.7 × 2.4 which, with the galaxy's distance, gives a diameter of 50,000 light-years.
Classification
NGC 1374 is an early-type galaxy with a Hubble classification of E1, indicating a flattening of 10%, but also it shows a subtle differentiation of light about halfway out of radius, which is indicating transition to S0 classification. It has a bright core surrounded by a soft hazy halo.
Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward.
Globular clusters
NGC 1374 is rich with globular clusters, with an estimated number of cluster of 406 ± 81. There are blue and red globular clusters, although red globulars are more populous than blue ones. A similar trend is present in NGC 1379 and NGC 1387. These globular clusters, like globulars in NGC 1379 and NGC 1387, did not show any evidences of multiple populations.
References
External links
Fornax Cluster
Elliptical galaxies
1374
Fornax
013267 | NGC 1374 | [
"Astronomy"
] | 397 | [
"Fornax",
"Constellations"
] |
61,486,284 | https://en.wikipedia.org/wiki/NGC%201375 | NGC 1375 is a barred lenticular galaxy in the constellation Fornax discovered by John Herschel on November 29, 1837. It is believed to be a member of the Fornax Cluster.
Distance and diameter estimates
It is at an estimated distance of 28 million light years. This distance is calculated from its estimated recession velocity, the lowest one in the entire Fornax Cluster, about 643 km/s. This led to uncertainties about its membership in the Fornax Cluster and also means that it is uncertain whether it forms a pair with another nearby galaxy in the night sky, NGC 1374. NGC 1375 may be a foreground galaxy that has nothing to do with the Fornax Cluster.
NGC 1375 is a member of the NGC 1386 Group, which also includes NGC 1386, NGC 1389 and NGC 1396, galaxies with similar uncertainties in distance. Its position in the night sky is near the center of the cluster and central galaxy NGC 1399, while the closest galaxy after NGC 1374, outside the pair, is NGC 1373. NGC 1375's size in the night sky is 2.3 x 0.9 which, with the galaxy's distance, gives a diameter of 23,000 light-years.
Classification
NGC 1375 is an early-type galaxy with a Hubble classification of SB0 pec, indicating it is a barred lenticular galaxy.
Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward. This is an early-type lenticular galaxy, with a similar nature to early-type ellipticals.
Boxy bulge
This galaxy contains a boxy bulge. It is one of the few lenticular galaxies containing such a bulge; another is NGC 1175. Boxy bulges have been found in mostly edge-on galaxies to date. The origin of this bulge is unknown. However, recent studies show they are not possible only for edge-on galaxies but for galaxies with an inclination of less than 70°, of type S0 and Sb, like NGC 1532, also in the Fornax Cluster. Boxy bulges found in other galaxies with much less inclination include those of barred spiral galaxies NGC 3049 and IC 676.
References
External links
Fornax Cluster
1375
Lenticular galaxies
Fornax
013266 | NGC 1375 | [
"Astronomy"
] | 511 | [
"Fornax",
"Constellations"
] |
61,486,848 | https://en.wikipedia.org/wiki/Rock%20analogs%20for%20structural%20geology | This is a compilation of the properties of different analog materials used to simulate deformational processes in structural geology. Such experiments are often called analog or analogue models. The organization of this page follows the review of rock analog materials in structural geology and tectonics of Reber et al. 2020.
Materials used to simulate upper crustal deformation
These materials need to exhibit brittle deformation upon failure as well as elastic and viscous deformation before failure.
Materials that simulate upper crustal deformation
Dry granular materials
Materials used to simulate deformation of the lower crust and mantle
Various fluids are used to simulate deformation of the lower crust and mantle, such as: linear, non-linear, and yield stress fluids.
Materials used to simulate deformation of the middle crust
Composite Model Materials
Composite materials combine phases with different physical properties. A common composite mixture contains dry granular materials and fluids. These analog materials have been used:
Sediment transport (Parker et al., 1982) using low viscosity fluids
Dynamics in the middle crust (Mookerjee et al., 2017; Reber et al., 2014) employing high viscosity fluids
Stick-slip dynamics (Higashi and Sumita, 2009; Reber et al., 2014)
Strain softening and hardening processes (Panien et al., 2006)
The most commonly used granular materials in composite mixtures are:
Sand
Glass beads
Acrylic discs
Common fluids used in composite mixtures are:
Carbopol
Silicone
Wax, which can behave as a brittle or viscous material depending on the melting temperature (Mookerjee et al., 2017)
Visco-elasto-plastic model materials
Visco-elasto-plastic deformation exhibits a combination of elastic, viscous, and plastic deformation at the same time. Various asphalts and bituminous materials demonstrate visco-elasto-plastic deformation but they are rarely as modeling materials (McBirney and Best, 1961).Common modeling materials demonstrating complex rheology are;
Carbopol (Piau, 2007; Shafiei et al., 2018)
Kaolinite clay (Cooke and van der Elst, 2012)
References
Structural geology
Earth sciences
Deformation (mechanics) | Rock analogs for structural geology | [
"Materials_science",
"Engineering"
] | 446 | [
"Deformation (mechanics)",
"Materials science"
] |
61,490,894 | https://en.wikipedia.org/wiki/NGC%201400 | NGC 1400 is an elliptical galaxy in the constellation Eridanus. At a distance of 65 million light-years from Earth, it was discovered by John Herschel in 1786. It is a member of the NGC 1407 group, whose brightest member is NGC 1407. The NGC 1407 group is part of the Eridanus Cluster, a cluster of 200 galaxies.
NGC 1400 is an early-type E0 galaxy. Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward.
NGC 1400 has had star formation in the past, which was caused by NGC 1400 falling into the NGC 1407 group.
One supernova has been observed in NGC 1400: SN 2021hcz (type Ia, mag. 15.4).
Gallery
References
External links
Elliptical galaxies
Eridanus (constellation)
1400
013470
Eridanus Group | NGC 1400 | [
"Astronomy"
] | 213 | [
"Eridanus (constellation)",
"Constellations"
] |
61,491,450 | https://en.wikipedia.org/wiki/Perovskite%20nanocrystal | Perovskite nanocrystals are a class of semiconductor nanocrystals, which exhibit unique characteristics that separate them from traditional quantum dots. Perovskite nanocrystals have an ABX3 composition where A = cesium, methylammonium (MA), or formamidinium (FA); B = lead or tin; and X = chloride, bromide, or iodide.
Their unique qualities largely involve their unusual band-structure which renders these materials effectively defect tolerant or able to emit brightly without surface passivation. This is in contrast to other quantum dots such as CdSe which must be passivated with an epitaxially matched shell to be bright emitters. In addition to this, lead-halide perovskite nanocrystals remain bright emitters when the size of the nanocrystal imposes only weak quantum confinement. This enables the production of nanocrystals that exhibit narrow emission linewidths regardless of their polydispersity.
The combination of these attributes and their easy-to-perform synthesis has resulted in numerous articles demonstrating the use of perovskite nanocrystals as both classical and quantum light sources with considerable commercial interest. Perovskite nanocrystals have been applied to numerous other optoelectronic applications such as light emitting diodes, lasers, visible communication, scintillators, solar cells, and photodetectors.
Physical properties
Perovskite nanocrystals possess numerous unique attributes: defect tolerance, high quantum yield, fast rates of radiative decay and narrow emission line width in weak confinement, which make them ideal candidates for a variety of optoelectronic applications.
Bulk vs. nano
The intriguing optoelectronic properties of lead halide perovskites were first studied in single crystals and thin films.: From these reports, it was discovered that these materials possess high carrier mobility, long carrier lifetimes, long carrier diffusion lengths, and small effective carrier masses. Unlike their nanocrystal counterparts, bulk ABX3 materials are non-luminescent at room temperature, but they do exhibit bright photoluminescence once cooled to cryogenic temperatures.
Defect-tolerance
Contrary to the characteristics of other colloidal quantum dots such as CdSe, ABX3 QDs are shown to be bright, high quantum yield (above 80%) and stable emitters with narrow linewidths without surface passivation. In II-VI systems, the presence of dangling bonds on the surface results in photoluminescence quenching and photoluminescent intermittence or blinking. The lack of sensitivity to the surface can be rationalized from the electronic band structure and density of states calculations for these materials. Unlike conventional II-VI semiconductors where the band gap is formed by bonding and antibonding orbitals, the frontier orbitals in ABX3 QDs are formed by antibonding orbitals composed of Pb 6s 6p and X np orbitals (n is the principle quantum number for the corresponding halogen atom). As a result, dangling bonds (under-coordinated atoms) result in intraband states or shallow traps instead of deep mid-gap states (e.g. d in CdSe QDs. This observation was corroborated by computational studies which demonstrated that the electronic structure of CsPbX3 materials exhibits a trap-free band gap. Furthermore, band structure calculations performed by various groups have demonstrated that these are direct band gap materials at their R-point (a critical point of the Brillouin zone) with a composition dependent band gaps.
Photoluminescence
It was discovered in 2015 that the photoluminescence of perovskite nanocrystals can be post-synthetically tuned across the visible spectral range through halide substitution to obtain , , , , and ; there was no evidence of . The change in band-gap with composition can be described by Vegard's Law, which describes the change in lattice parameter as a function of the change in composition for a solid solution. However, the change in lattice parameter can be rewritten to describe the change in band gap for many semiconductors. The change in band gap directly affects the energy or wavelength of light that can be absorbed by the material and therefore its color. Furthermore, this directly alters the energy of emitted light according to the Stokes shift of the material. This quick, post-synthetic anion-tunability is in contrast to other quantum dot systems where emission wavelength is primarily tuned through particle size by altering the degree of quantum confinement.
Aside from tuning the absorption edge and emission wavelength by anion substitution, it was also observed that the A-site cation also affects both properties. This occurs as a result of the distortion of the perovskite structure and the tilting of octahedra due to the size of the A-cation. Cs, which yields a Goldschmidt tolerance factor of less than one, results in a distorted, orthorhombic structure at room temperature. This results in reduced orbital overlap between the halide and lead atoms and blue shifts the absorption and emission spectra. On the other hand, FA yields a cubic structure and results in FAPbX3 having red shifted absorption and emission spectra as compared to both Cs and MA. Of these three cations, MA is intermediate size between Cs and FA and therefore results in absorption and emission spectra intermediate between those of Cs and FA. Through the combination of both anionic and cationic tuning, the whole spectrum ranging from near-UV to near-IR can be covered.
Absorption Coefficient
Recent studies have demonstrated that CsPbBr3 nanocrystals have an absorption coefficient of 2x105 cm−1 at 335 nm and 8x104 cm−1 at 400 nm.
Single Dot Spectroscopy of Perovskite Nanocrystals
Blinking and Spectral diffusion
Spectroscopic studies of individual nanocrystals have revealed blinking-free emission and very low spectral diffusion without a passivating shell around the NCs. Studies have also demonstrated blinking-free emission at room temperature with a strongly reduced Auger recombination rate at room temperature (CsPbI3 NCs).
Exciton fine-structure and the Rashba effect
It was observed that emission from perovskite nanocrystals may be the result of a bright (optically active) triplet state. Several effects have been suggested to play a role on the exciton fine structure such as electron-hole exchange interactions, crystal field and shape anisotropy, as well as the Rashba effect. Recent reports have described the presence of the Rashba effect within bulk- and nano- and . While it has been reported that the Rashba effect contributes to the existence of a lowest energy triplet state , recent work on has indicated the presence of a lower lying dark state, which can be activated with the application of a magnetic field.
Coherent emission
Numerous quantum optical technologies require coherent light sources. Perovskite nanocrystals have been demonstrated as sources of such light as well as suitable materials for the generation of single photons with high coherence.
Self-assembly and Superfluorescence
Monodisperse perovskite nanocrystals can be assembled into cubic superlattices, which can range from a few hundreds of nanometers to tens of microns in size and show tunable photoluminescence by changing nanocrystal composition via anion exchange (for example, from green-emitting CsPbBr3 nanocrystal superlattices to yellow and orange emitting nanocrystal superlattices to red-emitting CsPbI3 ones). These superlattices have been reported to exhibit very high degree of structural order and unusual optical phenomena such as superfluorescence. In the case of these superlattices, it was reported that the dipoles of the individual nanocrystals can become aligned and then simultaneously emit several pulses of light.
Chemical properties
Synthesis
Early attempts were made to prepare MAPbX3 perovskites as nanocrystals in 2014 by non-template synthesis. It was not until 2015 that CsPbX3 nanocrystals were prepared by the Kovalenko research group at ETH Zurich. by a hot-injection synthesis. Since then numerous other synthetic routes towards the successful preparation of ABX3 NCs have been demonstrated.
Hot-injection
The majority of papers reporting on ABX3 NCs make use of a hot injection procedure in which one of the reagents is swiftly injected into a hot solution containing the other reagents and ligands. The combination of high temperature and rapid addition of the reagent result in a rapid reaction that results in supersaturation and nucleation occurring over a very short period of time with a large number of nuclei. After a short period of time, the reaction is quenched by quickly cooling to room temperature. Since 2015, several articles detailing improvements to this approach with zwitterionic ligands, branched ligands and post-synthetic treatments have been reported. Recently, soy-lecithin was demonstrated to be a ligand system for these nanocrystals that could stabilize concentrations from several ng/mL up to 400 mg/mL.
Co-precipitation
A second, popular method for the preparation of ABX3 NCs relies on the ionic nature of APbX3 materials. Briefly, a polar, aprotic solvent such as DMF or DMSO is used to dissolve the starting reagents such as PbBr2, CsBr, oleic acid, and an amine. The subsequent addition of this solution into a non-polar solvent reduces the polarity of the solution and causes precipitation of the ABX3 phase.
Microfluidics
Microfluidics have been also used to synthesize CsPbX3 NCs and to screen and study synthetic parameters. Recently, a modular microfluidic platform has been developed at North Carolina State University to further optimize the synthesis and composition of these materials.
Other routes
Outside of the traditional synthetic routes, several papers have reported that CsPbX3 NCs could be prepared on supports or within porous structures even without ligands. Dirin et al. first demonstrated that bright NCs of CsPbX3 could be prepared without organic ligands within the pores of mesoporous silica. By using mesoporous silica as a template, the size of CsPbX3 nanodomains is restricted to the pore size. This allows for greater control over emission wavelength via quantum confinement and illustrates the defect tolerant nature of these materials. This concept was later extended to the preparation of ligand-free APbX3 NCs on alkali-halide supports that could be shelled with NaBr without deteriorating their optical properties and protecting the nanocrystals against a number of polar solvents.
As a result of the low melting point and ionic nature of ABX3 materials, several studies have demonstrated that bright ABX3 nanocrystals can also be prepared by ball-milling.
With NCs, the composition can be tuned via ion exchange i.e. the ability to post-synthetically exchange the ions in the lattice for those added. This has been shown to be possible for both anions and cations.
Anion exchange
The anions in the lead halide perovskites are highly mobile. The mobility arises from the diffusion of halide vacancies throughout the lattice, with an activation barrier of 0.29 eV and 0.25 eV for CsPbCl3 and CsPbBr3 respectively. (see: physical properties). This was used by Nedelcu et al. and Akkerman et al., to demonstrate that the composition of cesium lead halide perovskite nanocrystals could be tuned continuously from CsPbCl3 to CsPbBr3 and from CsPbBr3 to CsPbI3 to obtain emission across the entire visible spectrum. While this was first observed in a colloidal suspension, this was also shown in solid pellets of alkali halide salts pressed with previously synthesized nanocrystals. This same phenomenon has also been observed for MAPbX3 and FAPbX3 NCs. The anion exchange reaction has been investigated at the single nanocrystal level. In quantum-confined nanocrystals, the anion exchange leads to a uniform bandgap energy across the nanocrystal due to the quantum confinement effect. However, in nanocrystals larger than the Bohr diameter, multiple emission sites form, resulting in iodide- or bromide-rich regions.
Cation exchange and doping
Although several reports showed that CsPbX3 NCs could be doped with Mn2+, they accomplished this through the addition of the Mn precursor during the synthesis, and not through cation exchange. Cation exchange can be used to partially exchange Pb2+ with Sn2+, Zn2+, or Cd2+ over the course of several hours. In addition to these cations, gold was also shown to be a suitable candidate for cation exchange yielding a mixed-valent, and distorted, perovskite with the composition Cs2Au(I)Au(III)Br6. A-site cation exchange has also been shown to be a viable route for the transformation of CsPbBr3 to MAPbBr3 and from CsPbI3 to FAPbI3.
Ligand-assisted reprecipitation (LARP)
Ligand-assisted reprecipitation method is dedicated for the preparation of perovskite nanoplatelets (NPls). In this method, the precursors in different solvents whether polar like Dimethylformamide and Dimethyl sulfoxide or non-polar like toluene and hexane are added in the presence of the ligands to form the perovskite NPls theough supersaturation. The NPls thickness obtained from this method depends on the concentration of the ligands as well as the chain length of the organic ligands. Therefore, the thickness can be controlled by ratio between A-cation-oleate and lead-halide precursors in the reaction medium. By adjusting the toluene and acetone during the synthesis, the NPls are crystallized and precipitated at room temperature with these two solvents, respectively.
Morphology
Nanomaterials can be prepared with various morphologies that range from spherical particles/quantum wells (0D) to wires (1D) and platelets or sheets (2D), and this has been previously demonstrated for QDs such as CdSe. While the initial report of lead halide perovskite NCs covered cubic particles, subsequent reports demonstrated that these materials could also be prepared as both platelets (2D) and wires (1D). Due to the varying degrees of quantum confinement present in these different shapes, the optical properties (emission spectrum and mean lifetime) change. As an example of the effect of morphology, cubic nanocrystals of CsPbBr3 can emit from 470 nm to 520 nm based on their size (470 nm emission requires nanocrystals with an average diameter of less than 4 nm). Within this same composition (CsPbBr3), nanoplatelets exhibit emission that is blue shifted from that of cubes with the wavelength depending on the number of monolayers contained within the platelet (from 440 nm for three monolayers to 460 nm for 5 monolayers). Nanowires of CsPbBr3, on the other hand, emit from 473 nm to 524 nm depending on the width of the wire prepared with lifetimes also in the range of 2.5 ns – 20.6 ns.
Similarly to CsPbBr3, MAPbBr3 NCs also exhibit morphologically dependent optical properties with nanocrystals of MAPbBr3 emitting from 475 nm to 520 nm and exhibiting average lifetimes on the order of 240 ns depending on their composition. Nanoplatelets and nanowires have been reported to emit at 465 nm and 532 nm, respectively.
Structure and composition
Perovskite nanocrystal all have the general composition ABX3 in which A is a large, central cation (typically MA, FA, or Cs) that sits in a cavity surrounded by corner-sharing BX6 octahedra (B = Pb, Sn; X = Cl, Br, I). Depending on the composition, the crystal structure can vary from orthorhombic to cubic, and the stability of a given composition can be qualitatively predicted by its goldschmidt tolerance factor
where t is the calculated tolerance factor and r is the ionic radius of the A, B, and X ions, respectively. Structures with tolerance factors between 0.8 and 1 are expected to have cubic symmetry and form three dimensional perovskite structures such as those observed in CaTiO3. Furthermore, tolerance factors of t > 1 yield hexagonal structures (CsNiBr3 type), and t < 0.8 result in NH4CdCl3 type structures. If the A-site cation is too large (t >1), but packs efficiently, 2D perovskites can be formed.
Distortions and Phase transitions
The corner-sharing BX6 octahedra form a three-dimensional framework through bridging halides. The angle (Φ) formed by B-X-B (metal-halide-metal) can be used to judge the closeness of a given structure to that of an ideal perovskite. Although these octahedra are interconnected and form a framework, the individual octahedra are able to tilt with respect to one another. This tilting is affected by the size of the "A" cation as well as external stimuli such as temperature or pressure.
If the B-X-B angle deviates too far from 180°, phase transitions towards non-luminescent or all-together non-perovskite phases can occur. If the B-X-B angle does not deviate very far from 180°, the overall structure of the perovskite remains as a 3D network of interconnected octahedra, but the optical properties may change. This distortion increases the band gap of the material as the overlap between Pb and X based orbitals is reduced. For example, changing the A cation from Cs to MA or FA alters the tolerance factor and decreases the band gap as the B-X-B bond angle approaches 180° and the orbital overlap between the lead and halide atoms increases. These distortions can further manifest themselves as deviations in the band gap from that expected by Vegard's Law for solid solutions.
Crystal structure and twinning in nanocrystals
The room temperature crystal structures of the various bulk lead-halide perovskites have been extensively studied and have been reported for the APbX3 perovskites. The average crystal structures of the nanocrystals tend to agree with those of the bulk. Studies have, however, shown that these structures are dynamic and deviate from the predicted structures due to the presence of twinned nanodomains.
Surface chemistry
Calculations as well as empirical observations have demonstrated that perovskite nanocrystals are defect-tolerant semiconductor materials. As a result, they do not require epitaxial shelling or surface passivation since they are insensitive to surface defect states. In general, the perovskite nanocrystal surface is considered to be both ionic and highly dynamic. However, the ionic properties caused the instability of perovskite nanocrystals in humid condition and the degradation process can be accelerated by photoirradiation, which can alter the electronic properties of nanocrystals. Initial reports utilized dynamically bound oleylammonium and oleate ligands that exhibited an equilibrium between bound and unbound states. This resulted in severe instability with respect to purification and washing, which was improved in 2018 with the introduction of zwitterionic ligands. The stability and quality of these colloidal materials was further improved in 2019 when it was demonstrated that deep traps could be generated by the partial destruction of the lead-halide octahedra, and that they could also be subsequently repaired to restore the quantum yield of nanocrystals.
Applications and Devices
Light-emitting Diodes
Perovskite NCs are promising materials for the emitting layer of light-emitting diodes (LEDs) as they offer potential advantages over organic LEDs (OLEDs) such as the elimination of precious metals (Ir, Pt) and simpler syntheses. The first report of green electroluminescence (EL) was from MAPbBr3 NCs although no efficiency values were reported. It was later observed that MAPbBr3 NCs could form in a polymer matrix when the precursors for MAPbBr3 thin films were mixed with an aromatic polyidmide precursor. The authors of this study obtained green EL with an external quantum efficiency (EQE) of up to 1.2%.
The first LEDs based on colloidal CsPbX3 NCs demonstrated blue, green and orange EL with sub-1% EQE. Since then, efficiencies have reached above 8% for green LEDs (CsPbBr3 NCs), above 7% for red LEDs (CsPbI3 NCs), and above 1% for blue LEDs ).
Lasers
Perovskite MAPbX3 thin films have been shown to be promising materials for optical gain applications such as lasers and optical amplifiers. Afterwards, the lasing properties of colloidal perovskite NCs such as CsPbX3 nanocubes, MAPbBr3 nanoplatelets and FAPbX3 nanocubes were also demonstrated. Thresholds as low as 2 uJ cm−2 have been reported for colloidal NCs (CsPbX3) and 220 nJ cm−2 for MAPbI3 nanowires. Interestingly, perovskite NCs show efficient optical gain properties not only under resonant excitation, but also under two-photon excitation where the excitation light falls into the transparent range of the active material. While the nature of optical gain in perovskites is not yet clearly understood, the dominant hypothesis is that the population inversion of excited states required for gain appears to be due to bi-excitonic states in the perovskite.
Photocatalysis
Perovskite nanocrystals have also been investigated as potential photocatalysts.
Security
Perovskite nanocrystals doped with large cations such as ethylene diamine (en) were demonstrated to exhibit hypsochromaticity concomitantly with lengthened photoluminescence lifetimes relative to their undoped counterparts. This phenomenon was utilized by researchers to generate single color luminescent QR codes that could only be deciphered by measuring the photoluminescence lifetime. The lifetime measurements were carried out utilizing both time correlated single photon counting equipment as well as a prototype time-of-flight fluorescence imaging device developed by CSEM.
Other phases
Ternary cesium lead halides have multiple stable phases that can be formed; these include CsPbX3 (perovskite), Cs4PbX6 (so called "zero-dimensional" phase due to disconnected [PbX6]4- octahedra), and CsPb2X5. All three phases have been prepared colloidally either by a direct synthesis or via nanocrystal transformations.
A rising research interest in these compounds created a disagreement within the community around the zero-dimensional Cs4PbBr6 phase. Two contradicting claims exist regarding the optical properties of this material: i) the phase exhibits high photoluminescent quantum yield emission at 510-530 nm and ii) the phase is non-luminescent in the visible spectrum. It was later demonstrated that pure, Cs4PbBr6 NCs were non-luminescent, and that these could be converted to luminescent CsPbX3 NCs and vice versa.
A similar debate had occurred regarding the CsPb2Br5 phase, which was also reported as being strongly luminescent. This phase, like the Cs4PbBr6 phase, is a wide gap semiconductor (~3.1 eV), but it is also an indirect-semiconductor and is non-luminescent. The non-luminescent nature of this phase was further demonstrated in NH4Pb2Br5.
Lead-free perovskite nanocrystals
Given the toxicity of lead, there is ongoing research into the discovery of lead-free perovskites for optoelectronics. Several lead-free perovskites have been prepared colloidally: Cs3Bi2I9, Cs2PdX6, CsSnX3. CsSnX3 NCs, although the closest lead-free analogue to the highly luminescent CsPbX3 NCs, do not exhibit high quantum yields (<1% PLQY) CsSnX3 NCs are also sensitive towards O2 which causes oxidation of Sn(II) to Sn(IV) and renders the NCs non-luminescent.
Another approach to this problem relies on the replacement of the Pb(II) cation with the combination of a monovalent and a trivalent cation i.e. B(II) replaced with B(I) and B(III). Double perovskite nanocrystals such as Cs2AgBiX6 (X = Cl, Br, I), Cs2AgInCl6 (including Mn-doped variant), and Cs2AgInxBi1−xCl6 (including Na-doped variant) have been studied as potential alternatives to lead-halide perovskites, although none exhibit narrow, high PLQY emission.
See also
Quantum Dots
Perovskites
Perovskite (structure)
Light-emitting diode (LED)
Methylammonium lead halide
nanomaterials
Semiconductors
Optoelectronics
References
Materials science
Nanomaterials
Perovskites | Perovskite nanocrystal | [
"Physics",
"Materials_science",
"Engineering"
] | 5,478 | [
"Applied and interdisciplinary physics",
"Materials science",
"nan",
"Nanotechnology",
"Nanomaterials"
] |
61,492,213 | https://en.wikipedia.org/wiki/Fortschritt%20ZT%20320 | Fortschritt ZT 320 is a series of agricultural tractors made by the East German manufacturer VEB Traktorenwerk Schönebeck. It was produced from 1983 to 1990, and succeeded the ZT 300 series. Unlike its predecessor, the ZT 320 series came in only two models, the rear-wheel drive ZT 320, and the all-wheel drive ZT 323.
Concept
The ZT 320 series was meant to be an upgrade of the existing ZT 300 series, and therefore, many at the time not obsolete ZT 300 components, like the axles, frame, and steering system, were carried over to the ZT 320 series. The main parts that were supposed to receive an upgrade were, amongst other things, the three-point linkage, powertrain, driver's cab, and to fulfill contemporary regulations, the braking system. Compared to the ZT 300 series, the ZT 320 was also designed to be much more versatile. With its upgraded braking system, it can pull trailers with a mass of up to 30,000 kg, and its enhanced gearbox allows a very low speed of only 1.4 km/h. The production was simplified by reducing the number of models to two: The ZT 320 is the rear-wheel drive only model, whereas the ZT 323 also has front-wheel drive. Special purpose models were not part of the ZT 320 series.
Technical description
The ZT 320 series is a wheeled, two-axle tractor based upon the half frame design principle. Like any mid 20th century standard tractor, the ZT 320 series has an unsprung, rear beam axle that is directly flange-mounted to the gearbox. The rear axle is also directly connected to an additional ladder frame without any spring elements or shock absorbers in between. This ladder frame, the so-called half-frame, offers high torsional stiffness, and supports the engine as well as the driver's cab. In front, it connects to the front axle, which is either a pivoted but otherwise unsprung rigid dead (ZT 320) or live (ZT 323) axle. The rear axle differential, as well as the central differential, and the front axle differential (ZT 323 only) are lockable; the differential locks are operated pneumatically. The ZT 320 series has 18.4/15−34 rear tyres and either a single circuit (ZT 320) or dual circuit (ZT 323) braking system with drum brakes.
A hydraulically operated DK 80 dual clutch transmits the torque from the engine to the gearbox. Like its predecessor, the ZT 320 series has a powershift gearbox with three ranges, but the number of gears was upgraded from three to four. Powershifting is activated pneumatically, and can be operated with a switch on the dashboard. In total, the gearbox has 12 forward, and 8 reverse gears. At input torque greater than 250 N·m, the ZT 320's gearbox can reach an efficiency of more than 90% (range I, gear 4). The tractor's rear PTO shaft can be switched and has two settings: 540 min−1, (up to 56 kW), and 1000 min−1, (up to 67 kW). It also comes with a safety system that prevents transmitting too much power to farm implements. The ZT 320 model was available with an additional front PTO as a factory option.
A standard IFA 4 VD 14,5/12-1 SRW diesel engine, which was also used in the ZT 300 series, powers the ZT 320 series tractors. The 4 VD 14,5/12-1 SRW is a naturally aspirated, straight-four, water-cooled, diesel engine, that features MAN M-System wall-guided direct injection. It displaces 6.56 dm3 and is rated 73.5 kW at 1800 min−1. To reduce fuel consumption compared to the ZT 300 version, it received inlet ports with enhanced sickle-shaped chamfers, an optimised camshaft, and new fuel injectors. These measures resulted in a 2.9% reduction in fuel consumption, as well as better exhaust gas behaviour, and enhanced engine-torque increase. A reduction in engine noise was achieved by finning the valve covers, and making the cylinder-head cover of cast iron.
The driver's cab is mounted on the half-frame using special rubber shock-and-vibration absorbers. The interior is designed ergonomically, with an air-sprung driver's seat, well-placed levers and switches, and an adjustable steering column. Despite having a huge window area of 4.6 m2, the cab includes a roll cage. A ventilation system with slightly increased cabin pressure prevents dust from entering the driver's cab. Sound-deadening measures were used to keep the sound pressure level inside the cab below 85 dB.
Technical specifications
Drawbar pull
Source
References
External links
agrartechnik, volume 34, No. 6, Berlin 1984. (in German)
Die Kraftheberregelung des Traktors ZT 320/323
Arbeitshygienische Lösungen am Traktor ZT 320/323
Arbeitsproduktivität und Kraftstoffökonomie des Traktors ZT 320/323
Technik zur Bodenbearbeitung mit den Traktoren ZT 320/323
Fortschritt ZT 320 spare parts list (includes exploded view drawings)
Tractors
IFA vehicles | Fortschritt ZT 320 | [
"Engineering"
] | 1,148 | [
"Engineering vehicles",
"Tractors"
] |
61,493,359 | https://en.wikipedia.org/wiki/NGC%204056 | NGC 4056 is an elliptical galaxy located about 340 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer Albert Marth on March 18, 1865 and is a member of the NGC 4065 Group.
Although NGC 4056 is commonly equated with PGC 38140, there is still uncertainty in its identification.
See also
List of NGC objects (4001–5000)
References
External links
4056
038140
Coma Berenices
Astronomical objects discovered in 1865
Elliptical galaxies
NGC 4065 Group | NGC 4056 | [
"Astronomy"
] | 109 | [
"Coma Berenices",
"Constellations"
] |
61,493,545 | https://en.wikipedia.org/wiki/Lactarius%20acerrimus | Lactarius acerrimus is a member of the large milk-cap genus Lactarius in the order Russulales. It was first described by Max Britzelmayr in 1893.
Description
The mushroom's cap has between 5 and 15 cm in diameter. It sometimes takes a funneled shape when old. The lamella is cream-coloured when young, taking on an ochre colour as it matures. Its edge is smooth, undulated and irregular. The stem is short and stubby, measuring between 2 and 5 cm in length, and between 0.8 and 2 cm thick.
Distribution
The species can be found mainly in Europe, but has been reported in North America and in Morocco.
See also
List of Lactarius species
References
External links
acerrimus
Fungi described in 1893
Fungi of Europe
Fungus species | Lactarius acerrimus | [
"Biology"
] | 168 | [
"Fungi",
"Fungus species"
] |
78,156,278 | https://en.wikipedia.org/wiki/Traneurocin | Traneurocin (developmental code name NA-831), also known as cycloprolylglycine (CPG), is a racetam-like drug which is under development for the treatment of COVID-19, Alzheimer's disease, fragile X syndrome, Rett syndrome, major depressive disorder, and other neurological disorders. In the case of COVID-19, it is specifically being developed for treatment of COVID-19-induced neuropathy.
Pharmacology
Pharmacodynamics
The mechanism of action of traneurocin is either unknown or undisclosed. However, it has been described as acting as a positive allosteric modulator of the AMPA receptor and has been found to increase brain-derived neurotrophic factor (BDNF) levels. It has also been found to act as a positive allosteric modulator of the GABAA receptor. The drug is described as having neuroprotective, neurogenesis-stimulating, and pro-cognitive or nootropic effects. It has also been reported to have antihypoxic and anxiolytic properties.
Pharmacokinetics
It is known to be an endogenous compound present at micromolar concentrations in the rat brain and readily crosses the blood–brain barrier.
Chemistry
Chemically, traneurocin is a synthetic cyclized dipeptide composed of the amino acids glycine and proline.
Clinical trials
As of September 2024, traneurocin is in phase 3 clinical trials for COVID-19, phase 2 clinical trials for Alzheimer's disease, fragile X syndrome, and Rett syndrome, and phase 1 clinical trials for major depressive disorder. No development has been reported for treatment of other neurological disorders. Traneurocin was first developed, under the name cycloprolylglycine (CPG), in Russia in 1991 as a drug related structurally and pharmacologically to piracetam. Cycloprolylglycine is also related to and known to be the major metabolite of omberacetam (Noopept).
Another drug, vineurocin (NA-704), is also being developed for treatment of Alzheimer's disease. This drug is described as a recombinant growth hormone with neuroprotective and neurogenic effects.
See also
List of Russian drugs
References
External links
NeuroActiva - Pipeline (Including Traneurocin)
NA-831 - BioMed
NA-831 (traneurocin) - AlzForum
AMPA receptor positive allosteric modulators
Drugs with unknown mechanisms of action
Experimental antidepressants
Experimental drugs
Experimental drugs for Alzheimer's disease
GABAA receptor positive allosteric modulators
Ketones
Neuroprotective agents
Nootropics
Russian drugs
Pyrazines
Pyrrolidines
Pyrrolopyrazines
Cyclic peptides
Dipeptides | Traneurocin | [
"Chemistry"
] | 613 | [
"Ketones",
"Functional groups"
] |
78,156,661 | https://en.wikipedia.org/wiki/NNC%2001-0687 | NNC 01-0687 (also known as ADX-10061, CEE-03-310, or NNC-687) is a selective dopamine D1-like receptor antagonist of the benzazepine group which was under development as an experimental antipsychotic for the treatment of schizophrenia but was never marketed. Its development for schizophrenia was discontinued due to lack of effectiveness in clinical trials.
Subsequently, NNC 01-0687 was developed under the code name ADX-10061 for treatment of substance dependence and was studied for smoking cessation, alcohol dependence, and cocaine dependence. It was also developed for treatment of sleep disorders. However, development for all of these indications was also discontinued, by 2007, and the drug was never marketed for any use.
NNC 01-0687 was first described in the scientific literature by 1992.
See also
Berupipam (NNC 22-0010)
Ecopipam (SCH-39166)
Odapipam (NNC 01-0756)
SCH-23390
References
Abandoned drugs
Benzazepines
Benzofurans
D1 antagonists
Nitro compounds | NNC 01-0687 | [
"Chemistry"
] | 245 | [
"Drug safety",
"Abandoned drugs"
] |
78,156,975 | https://en.wikipedia.org/wiki/Suekichi%20Kinoshita | Suekichi Kinoshita (Japanese: 木下 季吉, Kinoshita Suekichi, 14 January 1877 – 28 November 1934) was a Japanese experimental physicist and pioneer in radioactivity. His main contribution include the first observation of alpha particles using nuclear emulsion photography.
Education and career
Kinoshita was the second son in an intellectual family, where his father Sukeyuki Kinoshita was a government official. His younger brother Kumao Kinoshita (1881–1947) was a marine biologist. Kinoshita studied physics at the Tokyo Imperial University (now University of Tokyo), graduating in 1902. He left Japan and first worked as an intern under Woldemar Voigt at the University of Göttingen. He then visited Ernest Rutherford's group at the Victoria University of Manchester (now University of Manchester) in the UK, where he stayed from 1907 to 1909. His groundbreaking research on alpha particles, based on the work done at Manchester, was first presented at the meeting of the British Science Association in Winnipeg in 1909, and was published shortly afterward in 1910. Upon returning to Japan, he taught physics at the Tokyo Imperial University from 1914 to 1933.
Kinoshita was awarded the Imperial Prize of the Japan Academy in 1923 for his work on radioactive particles.
Further reading
References
1877 births
1935 deaths
University of Tokyo alumni
People associated with the Victoria University of Manchester
Japanese physicists
Experimental physicists
Academic staff of the University of Tokyo
Particle physicists | Suekichi Kinoshita | [
"Physics"
] | 295 | [
"Particle physicists",
"Experimental physics",
"Experimental physicists",
"Particle physics"
] |
78,158,535 | https://en.wikipedia.org/wiki/RG-7351 | RG-7351 is a trace amine-associated receptor 1 (TAAR1) partial agonist that is or was under development for the treatment of major depressive disorder. It reached phase 1 clinical trials for this indication in 2010. However, as of November 2023, no further recent development has been reported since July 2016. The drug was developed by Hoffmann-La Roche.
See also
Ralmitaront (RG-7906; RO-6889450)
RG-7410
Ulotaront (SEP-363856; SEP-856)
References
Drugs with undisclosed chemical structures
Experimental antidepressants
TAAR1 agonists
TAAR1 antagonists | RG-7351 | [
"Chemistry"
] | 146 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
78,159,446 | https://en.wikipedia.org/wiki/PKS%200736%2B017 | PKS 0736+017 is a blazar located in the constellation of Canis Minor. This object is also a highly polarized compact radio quasar. Its source having a radio spectrum, appears to be flat, making it a flat spectrum radio quasar. It has a redshift of (z) 0.189 and is hosted in a large elliptical galaxy with a half light radius measurement of re = 13 kiloparsecs. The black hole mass in PKS 0736+017 is 7.32+0.89-0.91 x 107 Mʘ based on a full width at half maximum (FWHM) scaling factor and virial relation.
PKS 0736+017 is found violent variable across its electromagnetic spectrum. It showed an outburst in December 2001 where its brightness level reached a maximum of 14.90 in the B band, 13.79 in the R band and 14.34 in the V band. The spectral slope remained constant while brightness level showed a sharp decrease by 0.3 magnitude during 4.5 hours.
In 2002, PKS 0736+017 exhibited multiple variability behaviors. During most nights, the quasar was in an optical faint state displaying fluctuations on a small-scale. When observed during three nights, it became more variable and brighter. In its active state, PKS 0736+017 showed a rapid flare followed by quasi-periodic low-amplitude variations. Accompanied by the flare, were complex oscillations that soon continued and clearly shown once the quasar reached its high state. One week later, another flare was observed although not rapid as the first. During the quasar's brighten state, its color variation became redder.
In February 2015, the High Energy Stereoscopic System in Namibia, detected high-energy emission from PKS 0736+017 indicating the presence of a gamma ray flare. Prior in 2014, a near-infrared flare was seen in the quasar. In 2023, renewed gamma ray activity was detected by Large Area Telescope.
The optical domain of PKS 0736+017 shows strong forbidden and permitted emission lines. Not to mention, its broad hydrogen emission lines are known to show significant disparities. Between 1978 and 1980, the H-beta line intensity in PKS 0736+017 decreased by 40 percent, with it increasing by 50 percent between 1985 and 1986. As for its H-gamma line intensity, a large fractional change is seen. In additional, its visible spectrum is found identical to 3C 273, which both quasars have iron, hydrogen and helium permitted lines but no forbidden lines.
References
External links
PKS 0736+017 on SIMBAD
PKS 0736+017 on NASA/IPAC Extragalactic Database
Quasars
Blazars
Canis Minor
2825203
Active galaxies | PKS 0736+017 | [
"Astronomy"
] | 590 | [
"Canis Minor",
"Constellations"
] |
78,159,564 | https://en.wikipedia.org/wiki/Xiao%20Cheng%20Zeng | Xiao Cheng Zeng is a scientist in physical chemistry and materials science. He currently serves as the Head of Department of Materials Science & Engineering and a Chair Professor of Materials Chemistry and Chemical Engineering at City University of Hong Kong. He is also an Emeritus Chancellor's University Professor at University of Nebraska–Lincoln (USA). He is a fellow of the American Association for the Advancement of Science, a fellow of the American Physical Society, a fellow of US Materials Research Society, a fellow of Royal Society of Chemistry, and a foreign fellow of the European Academy of Sciences. He had also held a John Simon Guggenheim fellowship.
Education
He received his bachelor degree in Physics from Peking University in 1984. He then pursued postgraduate study in US via CUSPEA program (created by Nobel Laureate in Physics Professor Tsung-Dao Lee), and received his Ph.D. in Condensed Matter Physics from the Ohio State University in 1989. Thereafter, he did his postdoctoral research in Physical Chemistry at University of Chicago (1989–1992) and UCLA (1992–1993).
Career & Reaserch
As a computational physical chemist, Zeng has made original contributions to thermodynamics and phase transition of nanoconfined water/ice, and water/surface interaction and wetting; original contributions to gold-cluster science & nanocatalysis; atmospheric reactions; and computational design of low-dimensional materials.
Low-dimensional ice/ice hydrates: Zeng opened the field of low-dimensional ice/ice hydrates. In 1997, he predicted 2D bilayer hexagonal ice, nicknamed "the Nebraska ice"., a phase of water ice that is two-dimensional. And it was confirmed by two experiments: one by the Pacific Northwest National Laboratory in 2009 and another by the Peking University in 2020. Thereafter, this 2D bilayer hexagonal ice is named 2D ice I. Moreover, his theoretical predictions of the 1D ices (1D ice-nanotubes I-III), "DNA-ice", ferroelectric ice-χ, and 2D amorphous, plastic, and superionic ices enriched ice family.
Gold-cluster science & nanocatalysis: In 2006, he discovered the first all-metal cage molecules (Au16-18). Later, he resolved size/structure/catalytic-activity relationship of 20+ gold clusters; he also developed a grand-unified model to decipher structures of 70+ ligand-covered gold clusters.
Atmospheric reactions: Since 2015, he has found several new chemical reactions on water/cloud droplets with implications to atmospheric new particle formation and haze chemistry.
Computational design of low-dimensional materials: In 2011, he predicted 20+ metallic boron monolayer structures and created systematic naming series for these monolayers, including α, β, χ, and δ series; two in these series, χ3-borophene and β12-borophene were later confirmed by experiments.
Publications & Citations
Zeng's scientific accomplishments are documented in more than 700 journal publications with 59000+ citations in Google scholar (H-index 122) and 50000+ in Web of Science (H-index 109). These publications include 7 in Nature/Science, 23 in Nature/Science Sister Journals, 26 in Proc. Natl. Acad. Sci. (PNAS), 73 in Journal of the American Chemical Society (JACS), 30 in Angewandte Chemie/Advanced Materials, 9 in Phys. Rev. Lett./Phys. Rev. X, and 4 in Joule/Chem.
Prizes and Honours
Fellow, John Simon Guggenheim Memorial Foundation (2004)
Fellow, American Physical Society (2005)
Fellow, American Association for the Advancement of Science (2007)
Outstanding Research and Creative Activity Award, University of Nebraska (System Wide) (2010)
Midwest Award, American Chemical Society (2011)
Excellence in Graduate Education, Graduate College, UNL (2012)
Outstanding Postdoc Mentor Award, UNL (2013)
Fellow, Royal Society of Chemistry (2013)
Surfaces & Interfaces Award, Royal Society of Chemistry (2017)
Fellow, Materials Research Society (2019)
Highly Cited Researcher, Clarivate Web of Science (2019, 2020, 2021, 2022, 2023, 2024)
Foreign Fellow, European Academy of Sciences, Chemistry Division (2020)
References
External links
Xiao Cheng Zeng publications indexed by Google Scholar
Xiao Cheng Zeng publications indexed by Web of Science
https://www.cityu.edu.hk/mse/people/mse-faculty/zeng-xiaocheng
Year of birth missing (living people)
Living people
Chinese scientists
Scientists by century
Scientists by century and nationality
Physical chemists
Fellows of the American Association for the Advancement of Science | Xiao Cheng Zeng | [
"Chemistry"
] | 972 | [
"Physical chemists"
] |
78,159,609 | https://en.wikipedia.org/wiki/Fen%20%28land%29 | The fen () in Mandarin, fan in Cantonese or hun in Taiwanese, is a traditional Chinese unit of measurement for land area. One fen equals 1/10th of a mu in China mainland, Hong Kong and Taiwan.
Conversions
In China mainland,
1915 ~ 1929: 1 fen = 1⁄10 mu = 61.44 square meters = 73.48 square yards
1930 ~ present: 1 fen = 1⁄10 mu = 66+2⁄3 square meters = 79.73 square yards.
In Hong Kong and Macau, 1 fen = 1⁄10 mu = 76.14 square meters = 91.06 square yards.
In Taiwan and Japan, 1 fen = 1⁄10 jia = 969.92 square meters = 10,440 square feets.
Taiwan used to be ruled by Holand and then by Japan. Its measurement system was influenced by these two countries. And 1 fen has been set to be 1/10 of a Jia instead of a mu.
For details, please see article Mu (land).
Idioms
One mu and three fen of land, or 1.3 mu of land () is a Chinese idiom that figuratively refers to someone's small personal domain or limited territory, often implying a narrow scope of influence or control.
It is also the name of a Chinese website 1Point3Acres.
See also
Chinese units of measurement
Taiwanese units of measurement
Hong Kong units of measurement
References
Units of area
Customary units of measurement | Fen (land) | [
"Mathematics"
] | 294 | [
"Quantity",
"Units of area",
"Customary units of measurement",
"Units of measurement"
] |
78,159,611 | https://en.wikipedia.org/wiki/Li%20%28area%29 | Li () is a traditional unit of measurement for land area in China mainland. One li is 1/10th of a fen or 1/100 of a mu, equals 6+2⁄3 square meters or 7.973 square yards.
Conversions
In 1929, the Nationalist government of China promulgated the Weights and Measures Act to adopt the metric system as the official standard and to limit the newer Chinese units of measurement to private sales and trade. These newer "market" units are based on rounded metric numbers, and has been effective on China mainland since 1 January 1930.
For more details, please see article Mu (land).
See also
Chinese units of measurement
References
Units of area
Customary units of measurement | Li (area) | [
"Mathematics"
] | 143 | [
"Quantity",
"Units of area",
"Customary units of measurement",
"Units of measurement"
] |
78,159,616 | https://en.wikipedia.org/wiki/Qing%20%28area%29 | Qing () is a traditional unit of measurement for land area in China mainland. One qing is 100 mu, equals 6+2⁄3 ha or 16.47 acre.
Conversions
In 1929, the Nationalist government of China promulgated the Weights and Measures Act to adopt the metric system as the official standard and to limit the newer Chinese units of measurement to private sales and trade. These newer "market" units are based on rounded metric numbers, and has been effective on China mainland since 1 January 1930.
For more details, please see article Mu (land).
See also
Chinese units of measurement
References
Units of area
Customary units of measurement | Qing (area) | [
"Mathematics"
] | 129 | [
"Quantity",
"Units of area",
"Customary units of measurement",
"Units of measurement"
] |
78,160,954 | https://en.wikipedia.org/wiki/Ana%20Guadalupe | Ana R. Guadalupe Quiñones (born 1956) is a Puerto Rican chemist and academic academic administrator who served as the chancellor of the University of Puerto Rico, Río Piedras Campus from 2009 to 2013. She researches electrochemistry, specifically in the development of electrochemical sensors, biosensors, and electrocatalysts for applications in bioelectrochemistry and environmental monitoring.
Early life and education
Guadalupe was born in 1956. She attended the University of Puerto Rico, Río Piedras Campus (UPR-RP). She earned a B.Sc. in chemistry in 1979 and a M.Sc. in analytical chemistry in 1984. Her master's thesis was titled, Polymer-Modified Electrodes: Electrochemical Characterization and Analytical Applications for the Extraction of Metal Species in Aqueous Solutions. Between 1979 and 1981, Guadalupe worked as a laboratory instructor at the Universidad del Sagrado Corazón. She was a teaching assistant at UPR-RP, from 1981 to 1984.
In 1987, Guadalupe completed a Ph.D. in analytical chemistry, specializing in electrochemistry, at Cornell University. Her doctoral research focused on the electrochemical properties of chemically modified electrodes. Her dissertation was titled, Polymer Modified Electrodes: Electrochemical Characterization and Applications. Héctor D. Abruña was her doctoral advisor. She completed a postdoctoral fellowship in bioelectrochemistry at the University of North Carolina at Chapel Hill from 1987 to 1988.
Career
In 1988, Guadalupe became an assistant professor of chemistry at UPR-RP. Her research during this period focused on electrochemical processes, specifically the study of redox reactions and the development of electrochemical sensors. In 1989, she joined a collaborative project on the use of polymer-modified electrodes in bioelectrochemical applications, which laid the groundwork for her later research on biosensors. From 1988 to 1992, she was also an instructor at Interamerican University of Puerto Rico. She investigated sensor technology, working on the electrocatalytic oxidation of malate and lactate using ruthenium complexes, and the development of biosensors for the detection of compounds like nicotinamide adenine dinucleotide (NADH).
Guadalupe was promoted to associate professor in 1992 at UPR-RP, where she continued her work on electrochemical sensors and biosensors. Her research during this time included projects on polymer-supported electrodes, the controlled release of insulin, and the use of ruthenium complexes as molecular probes for enzyme-coupled reactions. By the mid-1990s, she was recognized for her expertise in bioelectrochemistry and had secured grants from the National Institutes of Health (NIH) and the National Science Foundation (NSF). In 1994, Guadalupe was appointed coordinator of the UPR-RP chemistry graduate program, a position she held until 1998. During this period, she supervised a number of graduate theses and expanded her research into areas such as the electrochemical production of nanoparticles and their application in catalysis.
In 1998, Guadalupe was promoted to professor of chemistry. Her work on electrochemical materials and nanostructured polymers garnered further recognition, and she began collaborating on interdisciplinary projects involving materials science and sensor technology. She also served as president of the Puerto Rico Science Teachers Association from 1991 to 1993 and was a member of the American Chemical Society, where she held various leadership roles, including president of the Puerto Rico chapter in 1998. From 2001 to 2009, she served as dean of graduate studies and research at UPR-RP, where she was responsible for overseeing the university's research initiatives and securing funding for projects in science and technology. During this time, she continued her research on electrochemical sensors and biosensors, contributing to advances in detecting environmental pollutants and pathogens like Salmonella.
In October 2009, Guadalupe was appointed acting chancellor of the UPR-RP. In this role, she provided leadership during a transitional period for the university, focusing on strengthening research and academic programs. Her tenure coincided with student protests from 2010 to 2011, sparked by an annual fee imposed by the University of Puerto Rico (UPR) board of trustees. Guadalupe called for police intervention during these protests, leading to violent confrontations and arrests, which drew widespread criticism from the student body. In March 2011, she was physically and verbally attacked by students, further intensifying the tensions. She resigned in May 2013 following a reconfiguration of the university's board of trustees. Her research in the period included the development of electrochemical materials and biosensors for environmental monitoring and public health applications. She also worked on projects involving the electrochemical characterization of porous silicon and the design of sensors for detecting waterborne diseases.
In 2021, Guadalupe was considered for the interim presidency of UPR, but her candidacy was met with opposition from students due to her controversial role during the protests. She was ultimately not selected as a finalist.
References
Living people
1956 births
Place of birth missing (living people)
Puerto Rican women scientists
21st-century Puerto Rican women educators
21st-century American women scientists
21st-century American chemists
American women chemists
University of Puerto Rico, Río Piedras Campus alumni
University of Puerto Rico faculty
American women academic administrators
Puerto Rican academic administrators
Analytical chemists
Cornell University alumni | Ana Guadalupe | [
"Chemistry"
] | 1,088 | [
"Analytical chemists"
] |
78,163,020 | https://en.wikipedia.org/wiki/Acetate%20pathway | The acetate pathway, also known as the polyketide pathway, is a fundamental biosynthetic route in organisms for the production of fatty acids and polyketides. This pathway operates at the interface of central metabolism and specialized metabolite synthesis, playing a crucial role in the synthesis of both primary and secondary metabolites.
It begins with acetyl-CoA and involves the stepwise condensation of two-carbon units, typically derived from malonyl-CoA, to form increasingly longer carbon chains. In fatty acid synthesis, these chains are fully reduced after each elongation step, while in polyketide synthesis, the reduction steps may be partially or completely omitted, leading to a diverse array of complex natural products. The acetate pathway is essential for the biosynthesis of vital cellular components such as membrane lipids, as well as a wide range of bioactive secondary metabolites, including many pharmaceutically important compounds.
References
Metabolic pathways | Acetate pathway | [
"Chemistry"
] | 200 | [
"Metabolic pathways",
"Metabolism"
] |
78,163,480 | https://en.wikipedia.org/wiki/Enefexine | Enefexine (), also known as 4-(4-ethylphenyl)piperidine, is a drug of the phenylpiperidine group which is described as an antidepressant but was never marketed. It was first described in the literature by 1983. The drug was developed by Ciba-Geigy.
See also
Budipine
(+)-CPCA
Femoxetine
Gamfexine
Paroxetine
References
4-Phenylpiperidines
Abandoned drugs
Experimental antidepressants | Enefexine | [
"Chemistry"
] | 116 | [
"Drug safety",
"Abandoned drugs"
] |
78,163,821 | https://en.wikipedia.org/wiki/Timi%C8%99oara%20Astronomical%20Observatory | Timișoara Astronomical Observatory is a research institute in Timișoara, Romania, founded on 7 December 1962 by . The scientific activity is coordinated by the Astronomical Institute of the Romanian Academy, and the administrative activity by the local branch of the Romanian Academy.
The Astronomical Observatory building has a basement, a ground floor and the equatorial instrument hall covered with a rotating dome. The dome and the main instrument of the observatory were made with own resources, in Timișoara. The optical instruments placed on the equatorial mount are:
a Cassegrain telescope with a 300/1690 mm Zeiss mirror equipped with an SBIG CCD camera, used for naked-eye observations and CCD stellar photometry, and
a 100/2000 mm Zeiss scope.
Due to the development of Timișoara, the pollution and brightness of the night sky has increased, so the location of the observatory is no longer appropriate. It is desired to move it to Muntele Mic in Caraș-Severin County.
References
Astronomical observatories in Romania
Astronomy institutes and departments
Buildings and structures in Timișoara | Timișoara Astronomical Observatory | [
"Astronomy"
] | 220 | [
"Astronomy organizations",
"Astronomy institutes and departments"
] |
78,163,913 | https://en.wikipedia.org/wiki/Cinfenine | Cinfenine () is a drug described as an antidepressant and coronary vasodilator which was never marketed. It was first described in the literature by 1970. The drug is similar in chemical structure to the modafinil derivative and atypical dopamine reuptake inhibitor JJC8-016, as well as to the antihistamine and anticholinergic diphenhydramine and derivatives of diphenhydramine like ebastine. Other notable analogues acting as dopamine reuptake inhibitors have been synthesized as well.
See also
List of modafinil analogues and derivatives
References
Abandoned drugs
Amines
Benzhydryl compounds
Drugs with unknown mechanisms of action
Experimental antidepressants
Modafinil analogues
Vasodilators | Cinfenine | [
"Chemistry"
] | 168 | [
"Drug safety",
"Functional groups",
"Amines",
"Bases (chemistry)",
"Abandoned drugs"
] |
78,164,038 | https://en.wikipedia.org/wiki/Monometacrine | Monometacrine (; developmental code name SD-735), also known as desmethyldimetacrine, is a drug of the tricyclic family described as an antidepressant which was never marketed. It was first described in the literature by 1966. The drug is the N-desmethyl analogue of dimetacrine and is a metabolite of dimetacrine.
References
Abandoned drugs
Experimental antidepressants
Human drug metabolites
Tricyclic antidepressants
Benzoquinolines
Secondary amines | Monometacrine | [
"Chemistry"
] | 116 | [
"Chemicals in medicine",
"Drug safety",
"Human drug metabolites",
"Abandoned drugs"
] |
78,164,160 | https://en.wikipedia.org/wiki/Tipindole | Tipindole (), also known as typindole, is a drug of the tricyclic family described as a serotonin antagonist and monoamine oxidase inhibitor (MAOI) which was never marketed. The drug was developed by Soviet researchers and was first described by 1962.
See also
List of Russian drugs
References
Abandoned drugs
Amines
Carboxylic acids
Monoamine oxidase inhibitors
Russian drugs
Serotonin receptor antagonists
Tricyclic compounds
Dimethylamino compounds
Ethanolamines
Indoles
Sulfur heterocycles | Tipindole | [
"Chemistry"
] | 113 | [
"Carboxylic acids",
"Drug safety",
"Functional groups",
"Amines",
"Bases (chemistry)",
"Abandoned drugs"
] |
78,164,251 | https://en.wikipedia.org/wiki/Integral%20of%20a%20correspondence | In mathematics, the integral of a correspondence is a generalization of the integration of single-valued functions to correspondences.
The first notion of the integral of a correspondence is due to Aumann in 1965, with a different approach by Debreu appearing in 1967. Integrals of correspondences have applications in general equilibrium theory in mathematical economics, random sets in probability theory, partial identification in econometrics, and fuzzy numbers in fuzzy set theory.
Preliminaries
Correspondences
A correspondence is a function , where is the power set of . That is, assigns each point with a set .
Selections
A selection of a correspondence is a function such that for every .
If can be seen as a measure space and as a Banach space , then one can define a measurable selection as an -measurable function such that for μ-almost all .
Definitions
The Aumann integral
Let be a measure space and a Banach space. If is a correspondence, then the Aumann integral of is defined as
where the integrals are Bochner integrals.
Example: let the underlying measure space be , and a correspondence be defined as for all . Then the Aumman integral of is .
The Debreu integral
Debreu's approach to the integration of a correspondence is more restrictive and cumbersome, but directly yields extensions of usual theorems from the integration theory of functions to the integration of correspondences, such as Lebesgue's Dominated convergence theorem. It uses Rådström's embedding theorem to identify convex and compact valued correspondences with subsets of a real Banach space, over which Bochner integration is straightforward.
Let be a measure space, a Banach space, and the set of all its convex and compact subsets. Let be a convex and compact valued correspondence from to . By Rådström's embedding theorem, can be isometrically embedded as a convex cone in a real Banach space , in such a way that addition and multiplication by nonnegative real numbers in induces the corresponding operation in .
Let be the "image" of under the embedding defined above, in the sense that is the image of under this embedding for every . For each pair of -simple functions , define the metric .
Then we say that is integrable if is integrable in the following sense: there exists a sequence of -simple functions from to which are Cauchy in the metric and converge in measure to . In this case, we define the integral of to be
where the integrals are again simply Bochner integrals in the space , and the result still belongs since it is a convex cone. We then uniquely identify the Debreu integral of as
such that . Since every embedding is injective and surjective onto its image, the Debreu integral is unique and well-defined.
Notes
References
Functional analysis
Mathematical economics | Integral of a correspondence | [
"Mathematics"
] | 589 | [
"Functions and mappings",
"Functional analysis",
"Applied mathematics",
"Mathematical objects",
"Mathematical relations",
"Mathematical economics"
] |
78,164,376 | https://en.wikipedia.org/wiki/Botiacrine | Botiacrine (; developmental code name Mo 876) is a drug of the tricyclic family described as an antiparkinsonian agent which was either never marketed or was possibly marketed outside of the United States. It was first described in the literature by 1965. The drug is an acridine derivative and is structurally related to the tricyclic antidepressant dimetacrine.
References
Abandoned drugs
Acridines
Amines
Antiparkinsonian agents
Tricyclic compounds
Benzoquinolines
Thiocarbamates | Botiacrine | [
"Chemistry"
] | 114 | [
"Functional groups",
"Drug safety",
"Amines",
"Bases (chemistry)",
"Abandoned drugs"
] |
78,164,437 | https://en.wikipedia.org/wiki/List%20of%20textbooks%20on%20relativity | Textbooks on the theory of relativity have been published by several notable physicists and mathematicians:
Special relativity
The primary sources section of the latter article in particular contains many additional (early) publications of importance in the field.
:For a translation see: s:Translation:The Relative Motion of the Earth and the Aether. Hendrik Lorentz was a major influence on Einstein's theory of special relativity. Lorentz laid the fundamentals for the work by Einstein and the theory was originally called the Lorentz-Einstein theory. After 1905 Lorentz wrote several papers on what he called "Einstein's principle of relativity".
"On the Electrodynamics of Moving Bodies". Translation by George Barker Jeffery and Wilfrid Perrett in The Principle of Relativity, London: Methuen and Company, Ltd. (1923)
"On the Electrodynamics of Moving Bodies". Translation by Megh Nad Saha in The Principle of Relativity: Original Papers by A. Einstein and H. Minkowski, University of Calcutta, 1920, pp. 1–34:
:Introduced the special theory of relativity. Reconciled Maxwell's equations for electricity and magnetism with the laws of mechanics by introducing major changes to mechanics close to the speed of light. One of the Annus Mirabilis papers.
:English translations: "Does the Inertia of a Body Depend Upon Its Energy Content?". Translation by George Barker Jeffery and Wilfrid Perrett in The Principle of Relativity, London: Methuen and Company, Ltd. (1923).
:Used the newly formulated theory of special relativity to introduce the mass energy formula. One of the Annus Mirabilis papers.
Henri Poincaré (1906) "On the Dynamics of the Electron", Rendiconti del Circolo Matematico di Palermo
*
**English translation: The Fundamental Equations for Electromagnetic Processes in Moving Bodies. In: The Principle of Relativity (1920), Calcutta: University Press, 1-69
** Translation by Meghnad Saha, "Space and Time" (1920): Wikisource link.
: Introduced the four-vector notation and the notion of Minkowski space, which was later adopted by Einstein and others.
E. T. Whittaker (1910) A History of the Theories of Aether and Electricity
, Wikisource translation: On the Non-Euclidean Interpretation of the Theory of Relativity
Henri Poincaré (1913) "The New Mechanics", The Monist Vol. XXIII, "The Relativity of Space", The Monist, Vol. XXIII.
Émile Borel (1914) Introduction Géométrique à quelques Théories Physiques, Gauthier-Villars
:Used concepts developed in the then-current textbooks (e.g., vector analysis and non-Euclidean geometry) to provide entry into mathematical physics with a vector-based introduction to quaternions and a primer on matrix notation for linear transformations of 4-vectors. The ten chapters are composed of 4 on kinematics, 3 on quaternion methods, and 3 on electromagnetism. Silberstein used biquaternions to develop Minkowski space and Lorentz transformations.
Frank Morley (1936), "When and Where", The Criterion, edited by Thomas Stearns Eliot, volume 15, pages 200-209.
Vladimir Karapetoff (1944) "The special theory of relativity in hyperbolic functions", Reviews of Modern Physics 16:33–52, Abstract & link to pdf
Also used biquaternions.
Google Books preview
N. David Mermin (2005) It's About Time: Understanding Einstein's Relativity, Princeton University Press
General relativity
: This publication is the first complete account of a general relativistic theory.
Hermann Weyl (1918) Raum, Zeit, Materie. 5 edns. to 1922 ed. with notes by Jūrgen Ehlers, 1980. trans. 4th edn. Henry Brose, 1922 Space Time Matter, Methuen, rept. 1952 Dover. .
Max Born (1920) – Based on Born's lectures at the University of Frankfurt am Main.
Available in English under the title .
Alfred North Whitehead (1922) The Principle of Relativity with applications to Physical Science
Einstein considered this the finest description of the theory of relativity in any language.
Charles Steinmetz (1923) Four Lectures on Relativity and Space
Ludwik Silberstein (1924) The Theory of Relativity, 2nd edition, enlarged @ Internet Archive
G. D. Birkhoff (1926) Relativity and Modern Physics, Google Books snippets
Wolfgang Pauli (1926) Relativitätstheorie, Klein's encyclopedia V.19 via Internet Archive
Wolfgang Rindler (1969) Essential Relativity: Special, General, and Cosmological, second edition 2001
(1200 pages)
Paul Dirac (1975) General Theory of Relativity, 69 pages, summarises Einstein's general theory of relativity.
Robert Wald (1984) General Relativity
References
Textbooks
Relativity
Textbooks on relativity
Relativity | List of textbooks on relativity | [
"Physics"
] | 1,037 | [
"Theory of relativity"
] |
78,164,525 | https://en.wikipedia.org/wiki/Triampyzine | Triampyzine (), also known as triampyzine sulfate (; developmental code name W-3976B) in the case of the sulfate salt, as (dimethylamino)trimethylpyrazine, or as 3,5,6-trimethylampyzine, is a drug described as an anticholinergic and antisecretory agent which was never marketed. It was first described in the literature by 1966. The drug is the 3,5,6-trimethylated derivative of ampyzine (W-3580B), which is also a drug and is, conversely, described as a "central stimulant".
References
Abandoned drugs
Aminopyrazines
Anticholinergics
Dimethylamino compounds | Triampyzine | [
"Chemistry"
] | 162 | [
"Drug safety",
"Abandoned drugs"
] |
78,164,629 | https://en.wikipedia.org/wiki/Benapryzine | Benapryzine (), or benaprizine (), also known as benapryzine hydrochloride ( in the case of the hydrochloride salt and sold under the brand name Brizin, is an antiparkinsonian agent and anticholinergic which has been used in the treatment of parkinsonism. As an anticholinergic, it is specifically a muscarinic acetylcholine receptor antagonist. Structurally, benapryzine is a benzilate, and is closely related to other antimuscarinic benzilate derivatives like benactyzine. The drug was first described in the literature by 1973.
References
Abandoned drugs
Antiparkinsonian agents
Benzilate esters
Deliriants
Muscarinic antagonists
Tertiary amines
Ethanolamines | Benapryzine | [
"Chemistry"
] | 169 | [
"Drug safety",
"Abandoned drugs"
] |
78,164,770 | https://en.wikipedia.org/wiki/Novella%20Bridges | Novella Bridges is an African American chemical engineer, researcher, and an advocate for minorities in STEM. She was born in 1972, and is a prominent figure in the field of inorganic chemistry. It was during her high school years that Bridges was introduced to the subject which she later pursued in her career. She earned a ,Ph.D. from Louisiana State University and began her career at the Pacific Northwestern National Laboratory (PNNL) specializing in radiochemistry. Bridges has held roles managing projects in nuclear security, nonproliferation, and radiation detection technology for health and safety organizations. She has received numerous accolades, including being named one of the Most Distinguished Women in Chemistry/Chemical Engineering.
Early life and education
Bridges was born on August 9, 1972, in Detroit, Michigan, making her the fifth child in her family. She attended Bethany Lutheran School and Lutheran High School East, where she developed a strong interest in science. Bridges' interest in science was sparked by her high school chemistry teacher (Keith Sprow), who encouraged her to pursue a career in the field. She furthered her education at Louisiana State University (LSU), earning a Ph.D. in inorganic chemistry in 2000.
Career
Bridges began her career as a research scientist at the Pacific Northwest National Laboratory (PNNL) in 2001. She specialized in radiochemistry and heavy metal separation techniques. Some of the specific projects which Bridges focused on were hydrogen storage, cancer treatment, and a chemical catalyst for diesel fuel emissions. Bridges later transitioned to the role of project manager, overseeing various projects funded by agencies such as the National Institutes of Health (NIH), National Science Foundation (NSF), and Department of Homeland Security (DHS). She played a key role in training US Customs and Border Protection officers on the use of radiation detection equipment.
Bridges worked as a program manager in the Office of Nuclear Nonproliferation Research and Development (DNN R&D) within the National Nuclear Security Administration (NNSA). She has managed a portfolio of R&D projects focused on nuclear security by developing strategies for securing nuclear materials and preventing nuclear proliferation as well as collaborating with national laboratories and other agencies on nuclear security initiatives.
Personal life
Bridges is single and has no children. She is a member of the First Baptist Church in Washington, D.C., where she participates in the college prep ministry. Bridges has participated in panel discussions related to women's history and empowerment, frequently celebrating, mentoring, and encouraging women and minorities pursuing careers in STEM fields. Bridges, in her spare time, tutors young girls who are interested in the sciences.
Recognition and awards
Bridges received a graduate fellowship award from Energy Corporation during her doctoral studies at LSU. She was also named the top female athlete at Jackson State University during her senior year for the sport of tennis. She was recognized as one of the 23 Most Distinguished Women in Chemistry/Chemical Engineering during the International Year of Chemistry in 2011. She has received several awards including the PNNL Woman of Achievement Award, a GEM fellowship, and a Rising Star Award from CCG. Bridges received an award from the American Chemical Society (ACS) for the "Regional Industrial Innovation" category in 2004.
References
Wikipedia Student Program
1972 births
Living people
Scientists from Detroit
American chemical engineers
21st-century American engineers
21st-century American women engineers
Louisiana State University alumni
Chemical engineers
Women chemical engineers
21st-century African-American scientists | Novella Bridges | [
"Chemistry",
"Engineering"
] | 690 | [
"Chemical engineering",
"Chemical engineers"
] |
78,164,822 | https://en.wikipedia.org/wiki/Lafadofensine | Lafadofensine (), also known as (3S)-N,N-bis(4-fluorophenyl)pyrrolidin-3-amine, is a drug described as an antidepressant which has not been marketed at this time. It is said to act as a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI). The drug was first described by 2010 and its was proposed by 2021.
See also
List of investigational antidepressants
2-Diphenylmethylpyrrolidine
Desoxypipradrol
References
4-Fluorophenyl compounds
Amines
Experimental antidepressants
Pyrrolidines
Serotonin–norepinephrine–dopamine reuptake inhibitors | Lafadofensine | [
"Chemistry"
] | 172 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
78,164,918 | https://en.wikipedia.org/wiki/Etamicastat | Etamicastat (; developmental code name BIA 5-453) is a peripherally selective dopamine β-hydroxylase (DBH) inhibitor which was under development for the treatment of hypertension (high blood pressure) and heart failure but was never marketed. The peripheral selectivity of etamicastat is in contrast to the earlier DBH inhibitor nepicastat, which is centrally active and produced associated side effects. Etamicastat was found to reduce blood pressure but not affect heart rate in clinical trials. The development of etamicastat was discontinued by August 2016.
See also
Nepicastat
Zamicastat
References
Abandoned drugs
Amines
Chromanes
Dopamine beta hydroxylase inhibitors
Fluoroarenes
Imidazoles
Peripherally selective drugs | Etamicastat | [
"Chemistry"
] | 163 | [
"Drug safety",
"Functional groups",
"Amines",
"Bases (chemistry)",
"Abandoned drugs"
] |
78,165,197 | https://en.wikipedia.org/wiki/Zelandopam | Zelandopam (; developmental code names YM-435, MYD-37) is a selective dopamine D1-like receptor agonist related to fenoldopam which was under development in Japan for the treatment of hypertension and heart failure but was never marketed. The drug was being developed for use by intravenous administration. The development of zelandopam appears to have been discontinued by the early 2000s. It was first described in the scientific literature by 1991.
References
Abandoned drugs
Catechols
D1-receptor agonists
Peripherally selective drugs
Tetrahydroisoquinolines
Tetrols | Zelandopam | [
"Chemistry"
] | 129 | [
"Drug safety",
"Abandoned drugs"
] |
78,165,313 | https://en.wikipedia.org/wiki/Berupipam | Berupipam (; developmental code name NNC 22-0010) is a selective dopamine D1 receptor antagonist of the benzazepine group which was under development for the treatment of psychotic disorders but was never marketed. It reached phase 1 clinical trials prior to the discontinuation of its development.
Berupipam and closely related dopamine D1 receptor antagonists were reported to have been generally well-tolerated in clinical trials, but side effects included restlessness, drowsiness, other central nervous system-related symptoms, and orthostatic hypotension.
Berupipam, in radiolabeled form, has been studied for use in positron emission tomography (PET) imaging. The drug was first described in the scientific literature by 1994.
See also
Ecopipam (SCH-39166)
NNC 01-0687 (ADX-10061)
Odapipam (NNC 01-0756)
SCH-23390
References
Abandoned drugs
Benzazepines
Benzofurans
Bromoarenes
Chloroarenes
D1 antagonists
Experimental drugs developed for schizophrenia | Berupipam | [
"Chemistry"
] | 242 | [
"Drug safety",
"Abandoned drugs"
] |
78,165,383 | https://en.wikipedia.org/wiki/Jin%20%28mass%29 | Jin (), or gan in Cantonese, kin in Taiwanese and Japanese, also called "Chinese pound" or "catty", is a traditional Chinese unit for weight measurement in East Asia. It originated in China before being introduced to neighboring countries.
Nowaday, the mass of 1 jin ranges between 500 to 610 grams in different places: 500 grams in mainland China, 600 grams in Taiwan, Japan, Korea and Thailand,
604.78982 grams in Hong Kong, and 604.8 grams in Singapore and Malaysia.
The Jin system is mostly used in the traditional markets, and famous for measuring gold, silver and Chinese medicines.
History
China has been using its weight measurement systems since the Zhou Dynasty, mostly with jin as the base unit.
In ancient China, there was an official post called "Sima" () in charge of the military affairs. Because the management of military grain and fodder involved plenty of weighing, the units of jin, liang, qian, fen eit. were also called as "Sima Jin" (), "Sima Liang", etc. And the measuring tools were called "Sima Scales" (). This is still true in today's Hong Kong. One Sima jin is equal to sixteen Sima liang, which is how the idiom "half a jin vs eight liangs" comes from.
The actual mass of the jin has changed in different eras and regions, but its ratio to other relevant units remains unchanged: One jin is equal to sixteen liangs, or 1/120 of a shi. Starting from the late Qing Dynasty, jin was also written in English as catty or kan based on the sounds of Malay language.
Before the Qing Dynasty, various regions and industries in China had their own weight standards for jin and liang.
During the Qing Dynasty, unified weights and measures were implemented. One jin was approximately 596.816 grams, which equaled 16 liangs.
China Mainland
Chinese mass units promulgated in 1915
On 7 January 1915, the Beiyang government promulgated a measurement law to use not only metric system as the standard but also a set of Chinese-style measures based directly on the Qing dynasty definitions ().
where liang is the base unit.
Mass units in the Republic of China since 1930
On 16 February 1929, the Nationalist government adopted and promulgated The Weights and Measures Act to adopt the metric system as the official standard and to limit the newer Chinese units of measurement to private sales and trade, effective on 1 January 1930. These newer "market" units are based on rounded metric numbers. And jin became the base unit.
Mass units in the People's Republic of China since 1959
On June 25, 1959, the State Council of the People's Republic of China issued the Order on the Unified Measurement System, retaining the market system, with the statement of "The market system originally stated that sixteen liangs are equal to one jin. Due to the trouble of conversion, it should be changed to ten liangs per jin. "
Legally, 1 jin equals 500 grams, and 10 liangs equals 1 jin (that is, 1 liang equals 50 grams). The traditional Chinese medicine measurement system remains unchanged (that is, 1 jin is 605 grams, and 16 liang is 1 jin).
Taiwan
The jin, or kin, in Taiwan is called "Taiwan jin" or Taijin (). The so-called Taijin is actually the jin used throughout China during the Qing Dynasty. In 1895, Taiwan was ceded to Japan. The Japanese implemented the metric system, but the Taiwanese still followed their own habits and continued to use the old weights and measures. When mainland China no longer used the old system of the Qing Dynasty, the old system of weights used in Taiwan naturally became the so-called "Taiwan system." 1 Taiwan jin is 600 grams, which is equal to 16 Taiwan liang, and 1 Taiwan liang is equal to 37.5 grams.
Hong Kong and Macau
Hong Kong and Macau mass units
According to the original Hong Kong law, Article 22 of 1884, one jin is 1 and 1⁄3 pounds (that is, 3 jins is equal to 4 pounds). Currently, Hong Kong law stipulates that one jin is equal to one hundredth of a dan or sixteen liangs, which is 0.60478982 kilograms.
Similarly, Singapore law stipulates that one jin, or "catty", is also equal to 1 1⁄3 pounds, which is equal to sixteen liangs (or "taels") or 0.6048 kilograms. Malaysia has the same regulations as it is a former British colony.
The word "catty" comes from Malay kati, meaning "the weight". It has also been borrowed into English as caddy, meaning "a container for storing tea".
Hong Kong troy units
These are used for trading precious metals such as gold and silver.
Japan
In Japan, 1 jin, or kin in Japanese pronunciation, is equal to 600 grams, but it is rarely used. The exception is the jin that is currently measured by the large piece of bread (food bread) before slicing the toast. According to the fair competition regulations of the Japanese Bread Fair Trade Council, a jin only needs to be more than 340 grams. Therefore, 510 grams can be called 1.5 jins.
The base unit of Japanese mass is the kan, although the momme is more common. It is a recognised unit in the international pearl industry. In English-speaking countries, momme is typically abbreviated as mo.
Korea
The base unit of Korean weight is the gwan. At the time of Korea's metrification, however, the pound was in more common use. Although it was usually taken as equivalent to 600g, as with red pepper and meats, a separate pound of 400g was used for fruits and another of 375 or 200g was used for vegetables. The nyang also sees some use among Korea's vendors of traditional Chinese medicine.
The "bag" (kama) was a variable unit usually figured as 54kg of unhusked rice or 60kg of polished rice, although 90kg "bags" were also used.
Vietnam
In Vietnam, the unit of jin is called "cân ta": 1 Sima jin (cân ta) = 0.6046 kilograms = 604.6 grams.
The following table lists common units of weight in Vietnam in the early 20th century:
Notes:
The cân (lit. "scale") is also called cân ta ("our scale") to distinguish it from the kilogram (cân tây, "Western scale").
Jin, pound and kilogram
The three mass units of "jin", "pound" and "kilogram" are all currently used in China. Their meanings and conversions in Mainland China are as follows:
(Chinese jin; character-by-character translation: "market jin"): Or simply called jin, is a traditional Chinese unit of weight, equals 500 grams.
(kilogram, "common jin"): An international metric unit, equivalent to 1000 grams.
(pound, "pound"): A British Imperial unit, about 453.6 grams.
1 Chinese jin =0.5 kilograms = 1.1023 pounds in Mainland China.
Idioms
wikt:幾斤幾兩 (jǐjīnjǐliǎng)
wikt:半斤八兩 (bànjīnbāliǎng)
wikt:缺斤少兩 (quējīnshǎoliǎng)
wikt:斤斤計較 (jīnjīnjìjiào)
See also
Chinese units of measurement
Hong Kong units of measurement
Taiwanese units of measurement
Japanese units of measurement
Korean units of measurement
Vietnamese units of measurement
Notes
References
External links
中國度量衡#衡
市制
斤
Units of mass
Chinese units of measurement
Customary units of measurement | Jin (mass) | [
"Physics",
"Mathematics"
] | 1,593 | [
"Matter",
"Quantity",
"Units of mass",
"Mass",
"Customary units of measurement",
"Units of measurement"
] |
78,165,434 | https://en.wikipedia.org/wiki/Odapipam | Odapipam (; developmental code names NNC 01-0756, NNC-756, NO-756) is a selective D1 receptor antagonist of the benzazepine group which was investigated as a potential antipsychotic but was never marketed.
It has more than 5,000-fold selectivity for the dopamine D1 receptor (Ki = 0.17nM) over the dopamine D2 receptor (Ki = 942nM). Its affinities for other dopamine receptors, such as the dopamine D5 receptor, were not reported. In addition to the dopamine D1 receptor, odapipam showed relatively high affinity for the serotonin 5-HT2 receptor (Ki = 4.5nM; 26-fold lower than for the D1 receptor).
The drug was first described in the scientific literature by 1988.
See also
Berupipam (NNC 22-0010)
Ecopipam (SCH-39166)
NNC 01-0687 (ADX-10061)
SCH-23390
References
5-HT2 antagonists
Abandoned drugs
Benzazepines
Benzofurans
Chloroarenes
D1 antagonists
Experimental drugs developed for schizophrenia
Hydroxyarenes | Odapipam | [
"Chemistry"
] | 275 | [
"Drug safety",
"Abandoned drugs"
] |
78,166,160 | https://en.wikipedia.org/wiki/Electro-pneumatic%20control | Electro-pneumatic control systems are built with electrical components to control pneumatic components (for example through electrically operated valves).
Description
The working medium, compressed air, is controlled by electrical signals.
In contrast to purely pneumatic controls, electro-pneumatic controls allow significantly more complex functions, especially through the use of electronic circuits such as programmable logic controls. The advantage of pneumatics lies in the simple and cost-effective implementation of actuators, for example with pneumatic cylinders.
Examples
Pipe organs:
Electro-pneumatic action
Tubular-pneumatic action
Railway brakes
Electro-pneumatic brake system on British railway trains
Electrostatic–pneumatic activation
Electropneumatic paintball marker
References
External links
Pneumatics
Control engineering | Electro-pneumatic control | [
"Engineering"
] | 159 | [
"Control engineering"
] |
78,166,914 | https://en.wikipedia.org/wiki/List%20of%20YouTube%20features | YouTube is an online video sharing platform owned by Google, founded on February 14, 2005 by Steve Chen, Chad Hurley, and Jawed Karim, and headquartered in San Bruno, California, United States. It is the second-most visited website in the world, after Google Search.
It offers different features based on user verification, such as standard or basic features like uploading videos, creating playlists, and using YouTube Music, with limits based on daily activity (verification via phone number or channel history increases feature availability and daily usage limits); intermediate or additional features like longer videos (over 15 minutes), live streaming, custom thumbnails, and creating podcasts; advanced features like content ID appeals, embedding live streams, applying for monetization, clickable links, adding chapters, and pinning comments on videos or posts.
As of October 2024 it includes multitask with the improved miniplayer, build, share, and vote on favorite YouTube playlists, set bedtime with Sleep Timer, and an upgrade on YouTube TV.
Video technology
YouTube primarily uses the VP9 and H.264/MPEG-4 AVC video codecs, and the Dynamic Adaptive Streaming over HTTP protocol. MPEG-4 Part 2 streams contained within 3GP containers are also provided for low bandwidth connections. By January 2019, YouTube had begun rolling out videos in AV1 format. In 2021 it was reported that the company was considering requiring AV1 in streaming hardware in order to decrease bandwidth and increase quality. Video is usually streamed alongside the Opus and AAC audio codecs.
At launch in 2005, viewing YouTube videos on a personal computer required the Adobe Flash Player plug-in to be installed in the browser. In January 2010, YouTube launched an experimental version of the site that used the built-in multimedia capabilities of Web browsers supporting HTML video. This allowed videos to be viewed without requiring Adobe Flash Player or any other plug-in to be installed. On January 27, 2015, YouTube announced that HTML video would be the default playback method on supported browsers. HTML video streams use Dynamic Adaptive Streaming over HTTP (MPEG-DASH), an HTTP-based adaptive bit-rate streaming solution optimizes the bitrate and quality for the available network.
The platform can serve videos at optionally lower resolution levels starting at 144p for smoother playback in areas and countries with limited Internet speeds, improving compatibility, as well as for the preservation of limited cellular data plans. The resolution can be adjusted automatically based on detected connection speed or set manually.
From 2008 to 2017, users could add "annotations" to their videos, such as pop-up text messages and hyperlinks, which allowed for interactive videos. By 2019, all annotations had been removed from videos, breaking some videos that depended on the feature. YouTube introduced standardized widgets intended to replace annotations in a cross-platform manner, including "end screens" (a customizable array of thumbnails for specified videos displayed near the end of the video).
In 2018, YouTube became an International Standard Name Identifier (ISNI) registry, and announced its intention to begin creating ISNI identifiers to uniquely identify the musicians whose videos it features.
Users can verify their account, normally through a mobile phone, to gain the ability to upload videos up to 12 hours in length, as well as produce live streams. Users who have built sufficient channel history and have a good track record of complying with the site's Community Guidelines will also gain access to these aforementioned features as well. When YouTube was launched in 2005, it was possible to upload longer videos, but a 10-minute limit was introduced in March 2006 after YouTube found that the majority of videos exceeding this length were unauthorized uploads of television shows and films. The 10-minute limit was increased to 15 minutes in July 2010. Videos can be at most 256 GB in size or 12 hours, whichever is less. , automatic closed captions using speech recognition technology when a video is uploaded are available in 13 languages, and can be machine-translated during playback.
YouTube also offers manual closed captioning as part of its creator studio. YouTube formerly offered a 'Community Captions' feature, where viewers could write and submit captions for public display upon approval by the video uploader, but this was deprecated in September 2020.
YouTube accepts the most common container formats, including MP4, Matroska, FLV, AVI, WebM, 3GP, MPEG-PS, and the QuickTime File Format. Some intermediate video formats (i.e., primarily used for professional video editing, not for final delivery or storage) are also accepted, such as ProRes. YouTube provides recommended encoding settings.
Each video is identified by an eleven-character case-sensitive alphanumerical Base64 string in the Uniform Resource Locator (URL) which can contain letters, digits, an underscore (_), and a dash (-).
In 2018, YouTube added a feature called Premiere which displays a notification to the user mentioning when the video will be available for the first time, like for a live stream but with a prerecorded video. When the scheduled time arrives, the video is aired as a live broadcast with a two-minute countdown. Optionally, a premiere can be initiated immediately.
Quality and formats
YouTube originally offered videos at only one quality level, displayed at a resolution of 320×240 pixels using the Sorenson Spark codec (a variant of H.263), with mono MP3 audio. In June 2007, YouTube added an option to watch videos in 3GP format on mobile phones. In March 2008, a high-quality mode was added, which increased the resolution to 480×360 pixels. In December 2008, 720p HD support was added. At the time of the 720p launch, the YouTube player was changed from a 4:3 aspect ratio to a widescreen 16:9. With this new feature, YouTube began a switchover to H.264/MPEG-4 AVC as its default video compression format. In November 2009, 1080p HD support was added. In July 2010, YouTube announced that it had launched a range of videos in 4K format, which allows a resolution of up to 4096×3072 pixels. In July 2010, support for 2160p UHD was added, with the videos playing at 3840 × 2160 pixels. In June 2014, YouTube began to deploy support for high frame rate videos up to 60 frames per second (as opposed to 30 before), becoming available for user uploads in October. YouTube stated that this would enhance "motion-intensive" videos, such as video game footage. In June 2015, support for 8K resolution was added, with the videos playing at 7680×4320 pixels. In November 2016, support for HDR video was added which can be encoded with hybrid log–gamma (HLG) or perceptual quantizer (PQ). HDR video can be encoded with the Rec. 2020 color space.
YouTube videos are available in a range of quality levels. Viewers only indirectly influence the video quality. In the mobile apps, users choose between "Auto", which adjusts resolution based on the internet connection, "High Picture Quality" which will prioritize playing high-quality video, "Data saver" which will sacrifice video quality in favor of low data usage and "Advanced" which lets the user choose a stream resolution. On desktop, users choose between "Auto" and a specific resolution. It is not possible for the viewer to directly choose a higher bitrate (quality) for any selected resolution.
Since 2009, viewers have had the ability to watch 3D videos. In 2015, YouTube began natively supporting 360-degree video. Since April 2016, it allowed live streaming 360° video, and both normal and 360° video at up to 1440p, and since November 2016 both at up to 4K (2160p) resolution. Citing the limited number of users who watched more than 90-degrees, it began supporting an alternative stereoscopic video format known as VR180 which it said was easier to produce, which allows users to watch any video using virtual reality headsets.
In response to increased viewership during the COVID-19 pandemic, YouTube temporarily downgraded the quality of its videos. YouTube developed its own chip, called "Argos", to help with encoding higher resolution videos in 2021.
In April 2023, YouTube began offering some videos in an enhanced bitrate "1080p Premium" option for YouTube Premium subscribers on iOS. In August 2023, the feature became available to subscribers on desktop platforms.
In certain cases, YouTube allows the uploader to upgrade the quality of videos uploaded a long time ago in poor quality. One such partnership with Universal Music Group included remasters of 1,000 music videos.
Live streaming
YouTube carried out early experiments with live streaming, including its YouTube Live event in 2008, a concert by U2 in 2009, and a question-and-answer session with US President Barack Obama in February 2010. These tests had relied on technology from 3rd-party partners, but in September 2010, YouTube began testing its own live streaming infrastructure. In April 2011, YouTube announced the rollout of YouTube Live. The creation of live streams was initially limited to select partners. It was used for real-time broadcasting of events such as the 2012 Olympics in London. In October 2012, more than 8 million people watched Felix Baumgartner's jump from the edge of space as a live stream on YouTube.
In May 2013, creation of live streams was opened to verified users with at least 1,000 subscribers; in August of the same year the number was reduced to 100 subscribers, and in December the limit was removed. In February 2017, live streaming was introduced to the official YouTube mobile app. Live streaming via mobile was initially restricted to users with at least 10,000 subscribers, but as of mid-2017 it has been reduced to 100 subscribers. Live streams support HDR, can be up to 4K resolution at 60 fps, and also support 360° video.
User features
Comment system
Most videos enable users to leave comments, which have attracted attention for the negative aspects of their form and content. In 2006, Time praised Web 2.0 for enabling "community and collaboration on a scale never seen before", and added that YouTube "harnesses the stupidity of crowds as well as its wisdom. Some of the comments on YouTube make you weep for the future of humanity just for the spelling alone, never mind the obscenity and the naked hatred". The Guardian in 2009 described users' comments on YouTube as:
The Daily Telegraph commented in September 2008, that YouTube was "notorious" for "some of the most confrontational and ill-formed comment exchanges on the internet", and reported on YouTube Comment Snob, "a new piece of software that blocks rude and illiterate posts". The Huffington Post noted in April 2012 that finding comments on YouTube that appear "offensive, stupid and crass" to the "vast majority" of the people is hardly difficult.
Google subsequently implemented a comment system oriented on Google+ on November 6, 2013, that required all YouTube users to use a Google+ account to comment on videos. The stated motivation for the change was giving creators more power to moderate and block comments, thereby addressing frequent criticisms of their quality and tone. The new system restored the ability to include URLs in comments, which had previously been removed due to problems with abuse. In response, YouTube co-founder Jawed Karim posted the question "why the fuck do I need a google+ account to comment on a video?" on his YouTube channel to express his negative opinion of the change. The official YouTube announcement received 20,097 "thumbs down" votes and generated more than 32,000 comments in two days. Writing in the Newsday blog Silicon Island, Chase Melvin noted that "Google+ is nowhere near as popular a social media network like Facebook, but it's essentially being forced upon millions of YouTube users who don't want to lose their ability to comment on videos" and added that "Discussion forums across the Internet are already bursting with the outcry against the new comment system". In the same article Melvin goes on to say:
Later, on July 27, 2015, Google announced in a blog post that it would be removing the requirement to sign up to a Google+ account to post comments to YouTube. On November 3, 2016, YouTube announced a trial scheme which allows the creators of videos to decide whether to approve, hide or report the comments posted on videos based on an algorithm that detects potentially offensive comments. Creators may also choose to keep or delete comments with links or hashtags to combat spam. They can also allow other users to moderate their comments.
In December 2020, it was reported that YouTube would launch a new feature that will warn users who post a comment that "may be offensive to others."
Community
On September 13, 2016, YouTube launched a public beta of Community, a social media-based feature that allows users to post text, images (including GIFs), live videos and others in a separate "Community" tab on their channel. Prior to the release, several creators had been consulted to suggest tools Community could incorporate that they would find useful; these YouTubers included Vlogbrothers, AsapScience, Lilly Singh, The Game Theorists, Karmin, The Key of Awesome, The Kloons, Peter Hollens, Rosianna Halse Rojas, Sam Tsui, Threadbanger and Vsauce3.
After the feature has been officially released, the community post feature gets activated automatically for every channel that passes a specific threshold of subscriber counts or already has more subscribers. This threshold was lowered over time, from 10,000 subscribers to 1500 subscribers, to 1000 subscribers, to 500 subscribers.
Channels that the community tab becomes enabled for, get their channel discussions (previously known as channel comments) permanently erased, instead of co-existing or migrating.
TestTube
Experimental features of YouTube could be accessed in an area of the site formerly named TestTube.
For example, in October 2009, a comment search feature accessible under /comment_search was implemented as part of this program, however the feature was later removed. Later the same year, YouTube Feather was introduced as a "lightweight" alternative website for countries with limited internet speeds. Following the transition to the Polymer layout, TestTube was disabled, and the URL redirects to video playback settings. TestTube was replaced by a new system that requires users to be subscribed to YouTube Premium in order to enable or disable experiments.
Content accessibility
YouTube offers users the ability to view its videos on web pages outside their website. Each YouTube video is accompanied by a piece of HTML that can be used to embed it on any page on the Web. This functionality is often used to embed YouTube videos in social networking pages and blogs. Users wishing to post a video discussing, inspired by, or related to another user's video can make a "video response". The eleven character YouTube video identifier (64 possible characters used in each position), allows for a theoretical maximum of 6411 or around 73.8 quintillion (73.8 billion billion) unique ids.
YouTube announced that it would remove video responses for being an underused feature on August 27, 2013. Embedding, rating, commenting and response posting can be disabled by the video owner. YouTube does not usually offer a download link for its videos, and intends for them to be viewed through its website interface. A small number of videos can be downloaded as MP4 files. Numerous third-party web sites, applications and browser plug-ins allow users to download YouTube videos.
In February 2009, YouTube announced a test service, allowing some partners to offer video downloads for free or for a fee paid through Google Checkout. In June 2012, Google sent cease and desist letters threatening legal action against several websites offering online download and conversion of YouTube videos. In response, Zamzar removed the ability to download YouTube videos from its site. Users retain copyright of their own work under the default Standard YouTube License, but have the option to grant certain usage rights under any public copyright license they choose.
Since July 2012, it has been possible to select a Creative Commons attribution license as the default, allowing other users to reuse and remix the material.
Platforms
Most modern smartphones are capable of accessing YouTube videos, either within an application or through an optimized website. YouTube Mobile was launched in June 2007, using RTSP streaming for the video. Not all of YouTube's videos are available on the mobile version of the site.
Since June 2007, YouTube's videos have been available for viewing on a range of Apple products. This required YouTube's content to be transcoded into Apple's preferred video standard, H.264, a process that took several months. YouTube videos can be viewed on devices including Apple TV, iPod Touch and the iPhone.
The mobile version of the site was relaunched based on HTML video in July 2010, avoiding the need to use Adobe Flash Player and optimized for use with touch screen controls. The mobile version is also available as an app for the Android platform.
In September 2012, YouTube launched its first app for the iPhone, following the decision to drop YouTube as one of the preloaded apps in the iPhone 5 and iOS 6 operating system. According to GlobalWebIndex, YouTube was used by 35% of smartphone users between April and June 2013, making it the third-most used app.
A TiVo service update in July 2008 allowed the system to search and play YouTube videos.
In January 2009, YouTube launched "YouTube for TV", a version of the website tailored for set-top boxes and other TV-based media devices with web browsers, initially allowing its videos to be viewed on the PlayStation 3 and Wii video game consoles.
During the month of June that same year, YouTube XL was introduced, which has a simplified interface designed for viewing on a standard television screen. YouTube is also available as an app on Xbox Live.
On November 15, 2012, Google launched an official app for the Wii, allowing users to watch YouTube videos from the Wii channel. An app was available for Wii U and Nintendo 3DS, but was discontinued in August 2019. Videos can also be viewed on the Wii U Internet Browser using HTML video. Google made YouTube available on the Roku player on December 17, 2013, and, in October 2014, the Sony PlayStation 4.
YouTube launched as a downloadable app for the Nintendo Switch in November 2018.
International and localization
In early years of operation, Google faced some criticism for 'encouraging the dominance of US values', by prioritising English over other languages. On June 19, 2007, at a conference in Paris, Google CEO Eric Schmidt launched YouTube localization, with stated aims including customizing the YouTube experience by country, including country-specific comments, metrics, and video rankings. From 2007, YouTube's localization was rolled out.
A 2015 report on YouTube's localization showed it to be continuing, and expanding. In February 2023, YouTube made it possible to upload a single video in multiple languages. Prior to 2023, the only option for YouTubers to broaden their content's reach to audiences speaking different languages was to launch an entirely separate secondary channel for each language and upload dubbed versions of their videos across all those channels. MrBeast called multi-language dub tracks a “giant win” for creators. With the introduction of the dubbing localization option, many creators switched from uploading to separate channels to uploading to their main channel with dubbed versions.
YouTube localization by country
As of 2024, the interface of YouTube is available with localized versions in 109 countries, two territories (Hong Kong & Puerto Rico) and a worldwide version and continues to extend the availability of its localized version to additional countries and regions.
If YouTube is unable to identify a specific country or region according to the IP address, the default location is the United States. However, YouTube offers language and content preferences for all accessible countries, regions, and languages.
The YouTube interface suggests which local version should be chosen based on the IP address of the user. In some cases, the message "This video is not available in your country" may appear because of copyright restrictions or inappropriate content. The interface of the YouTube website is available in 76 language versions, including Amharic, Albanian, Armenian, Burmese, Haitian Creole, Kyrgyz, Malagasy, Mongolian, Persian, Samoan, Somali and Uzbek, which do not have local channel versions. Access to YouTube was blocked in Turkey between 2008 and 2010, following controversy over the posting of videos deemed insulting to Mustafa Kemal Atatürk and some material offensive to Muslims. In October 2012, a local version of YouTube was launched in Turkey, with the domain youtube.com.tr. The local version is subject to the content regulations found in Turkish law. In March 2009, a dispute between YouTube and the British royalty collection agency PRS for Music led to premium music videos being blocked for YouTube users in the United Kingdom. The removal of videos posted by the major record companies occurred after failure to reach an agreement on a licensing deal. The dispute was resolved in September 2009. In April 2009, a similar dispute led to the removal of premium music videos for users in Germany.
References
External links
YouTube-related lists
Software features | List of YouTube features | [
"Technology"
] | 4,417 | [
"Software features"
] |
78,167,539 | https://en.wikipedia.org/wiki/H1426%2B428 | H1426+428 also known as 1ES 1426+428, is a high-frequency peaked BL Lacertae object (HBL) located in the constellation of Boötes. It is located at a relatively high redshift of (z) 0.129, and was discovered in 1984 by astronomers who presented a catalogue of X-ray sources taken with the HEAO 1 satellite.
H1426+428 is classified as a blazar. It is also a distant source of TeV gamma rays. It has low power and a synchrotron peak that is above 100 KeV. Furthermore, H1426+428 is possibly hosted in an elliptical galaxy and is luminous in X-ray bands. It has a 2-6 keV luminosity of ~1044 erg s−1.
The gamma emission in H1426+428 is found to have an average flux. Its spectrum is very steep and shows a differential spectral index of γ = -3.60 ± 0.57, when observed by the Cosmic Anisotropy Telescope (CAT) in Very High energy gamma ray bands between 1998 and 2000. This steep spectrum is mainly contributed by the absorption of gamma rays in the intergalactic medium or by diffused cosmic infrared background.
In 2002, H1426+428 exhibited variability in the 3-24 keV X-ray spectra. However in 2006, it was in a period of X-ray inactivity, showing no gamma rays, when observed by CELESTE Cherenkov telescope . The Tev activity in H1426+428 only increased just before 2008, with it experiencing flare activity for four days in 2009. A long-term X-ray flare was detected in H1426+428 in January 2021 by the X-ray telescope onboard Neil Gehrels Swift Observatory. This was followed by a very high energy gamma ray flux in March 2021.
H1426+428 has a compact radio core with a ~ 17 mJy flux density. In additional, it has a faint radio jet extending towards northwest with a project position angle of -25°. There is also a faint radio halo that is surrounding the radio core as well but it has weak radio and optical polarization.
References
External links
H1423+428 on SIMBAD
H1423+428 on NASA/IPAC Extragalactic Database
BL Lacertae objects
Boötes
Blazars
Active galaxies
2203750
Astronomical objects discovered in 1984 | H1426+428 | [
"Astronomy"
] | 513 | [
"Boötes",
"Constellations"
] |
72,381,982 | https://en.wikipedia.org/wiki/L%27%C3%AEle%20du%20Gouvernement | l'île du Gouvernement is an island in the St. Brandon archipelago. The island is uninhabited, and mostly functions as a bird and turtle sanctuary.
This island was one of those recommended as part of the St. Brandon Marine Protected Area (MPA) by the World Bank in 1998. The World Bank’s Management Plan was accepted at Ministry level in its ”Blue Print for the Management of St. Brandon” (2002) which was thereafter approved by the government of Mauritius in 2004.
References
Islands of St. Brandon
Mascarene Islands
Outer Islands of Mauritius
Reefs of the Indian Ocean
Fishing areas of the Indian Ocean
Insular ecology
Important Bird Areas of Mauritius
Flora of Mauritius
Atolls of the Indian Ocean
Biodiversity
Conchology | L'île du Gouvernement | [
"Biology"
] | 149 | [
"Biodiversity"
] |
72,382,129 | https://en.wikipedia.org/wiki/L%27%C3%AEle%20du%20Sud | L'île du Sud (South Island, l'île Boisées) is an island located in the St. Brandon archipelago. It is one of the three islands (the others being Île Raphael and L'Île Coco) used as a base of operations for fishing activities by Raphael Fishing Company, the only resident fishing company in the Cargados Carajos shoals under a 1901 contract with the government of Mauritius.
Shipwrecks
On 1 February 2015, the fishing vessel, Kha Yang, with of fuel in its tanks, ran aground on the reef off L'île du Sud. Twenty crew were rescued shortly after its grounding, and a salvage operation pumped the fuel from its tanks a few weeks later.
On 5 December 2022, the Taiwanese fishing vessel, 41 FV YU FENG 67, ran aground off L'île du Sud. Its crew of 20 were later rescued by the local commercial fishing boats of Raphael Fishing Company, in the presence of the National Coast Guard. The vessel is now an effective shipwreck, and more than 20 tons of diesel were spilled into the fragile lagoon, affecting coral life and associated flora and fauna.
See also
St. Brandon
Île Raphael
Raphaël Fishing Company
Avocaré Island
L'île du Gouvernement
Île Verronge
Casting (fishing)
Fishing tournament
Fly Casting Analyzer
Constitution of Mauritius
permanent grant
Mauritian Wildlife Foundation
References
External links
Australian Bureau of Meteorology - Understanding tropical cyclone categories
Regional specialized meteorological centres
India Meteorological Department – Bay of Bengal and the Arabian Sea
Météo-France – La Reunion – South Indian Ocean from 30°E to 90°E
Tropical cyclone warning centres
Australian Bureau of Meteorology . – South Indian Ocean & South Pacific Ocean from 90°E to 160°E, south of 10°S
Islands of St. Brandon
Outer Islands of Mauritius
Reefs of the Indian Ocean
Fishing areas of the Indian Ocean
Atolls of the Indian Ocean
Marine conservation
Protected areas
Oceanography
Fisheries science
Fisheries law
2022 disasters in Africa
Maritime incidents in 2022 | L'île du Sud | [
"Physics",
"Environmental_science"
] | 404 | [
"Oceanography",
"Hydrology",
"Applied and interdisciplinary physics"
] |
72,382,191 | https://en.wikipedia.org/wiki/Collybiopsis%20confluens | Collybiopsis confluens, commonly known as the clustered toughshank, is a type of mushroom from the Omphalotaceae family. The fruiting body appears from summer until autumn in deciduous and coniferous forests. Collybiopsis confluens is not an edible mushroom.
Traits
Macroscopic traits
The thin-fleshed cap is wide, arched or flattened, and more or less convex. The cap is smooth, matte and faintly ochre or faintly brown depending on humidity. The colours turn pale to a whiteish tone when the cap is dry. Mature fruiting bodies have a wavy and slightly grooved edge.
The lamella are strikingly tightly packed and almost exposed. In early stages, they are whiteish and later turn from a cream to leather-yellow or pink-brownish colour. The spore powder is white.
The stem can be up to long, stiff, hollow, smooth and grooved along its length. It is red-brownish coloured and purple-grey and frosted with fine flakes. The tip of the stem is expanded, resembling a button, at the base of the gills. The base is covered with a white felty mycelium weave. The thin, tough flesh is cream-brownish and gives off a weak, aromatic mushroom scent. Its taste is described as mild.
Microscopic traits
The smooth, inamyloid spores are 7–10 μm long and 3.5–4.2 (–5) μm wide. They are slightly tear-shaped, ellipsoid or spindle shaped. They are not cyanophilic, meaning that they cannot be dyed with methyl blue. The club-shaped, basidia containing four spores are 22.4–26.6 μm × 5–7 μm big. Pleurocystidia are absent, but there are many 27.5–70 μm long and 2.8–5.6 μm wide cheilocystidia. They are unevenly club- or cylinder-shaped and twisting. In some instances, they can be unevenly battered or branched like coral. The inamyloid Lamellartrama is parallel to interwoven. The hypha are 3.5–7.8 (–14.8) μm wide, smooth, thin-walled and translucent. They partially contain strongly refractive lipid droplets. The Huttrama is inamyloid and loosely interwoven. The Hyphen are 5.5–13.2 μm wide. The skin of the cap (Pileipellis) is only slightly differentiated and consists of crawling, branched, and radially orientated hyphen. The hyaline and thin walled cells are 2.8–7 μm wide and mostly smooth. Occasionally, they can be spirally and unevenly encrusted by a fine, faint yellow-brown pigment. Clamp connections are present in all tissues.
Differentiation
Amateurs would find it easy to confuse Collybiopsis confluens with other types of mushrooms. Characteristic of this species are the narrow-standing lamellae, the thin-fleshed, reddish-brown and quickly-fading cap and the tough, gristly stem, which is usually noticeably hairy and quite long in relation to the diameter of the cap. The tufted growth is also typical for this species.
Gymnopus peronatus can be similar. This also has lamella far apart from each other, yellow lamella when the mushroom is young, light brown lamellae when the mushroom is old, tastes burning hot and grows fewer tufts.
Ecology
This species appears in almost every native forest, as well as in common forest communities. They mainly contain adult copper beeches. The fruiting body appears from July to November mostly in rows of clusters or fairy circles from 1 to 5 meters in diameter. As a substrate, deciduous and coniferous trees serve very well, however they grow most frequently on copper beech wood. The mushrooms appear from lowland to high mountain land.
Distribution
Collybiopsis confluens is widely spread throughout Pakistan and the Holarctic realm. In the Holoartic realm, the distribution area reaches from the meridian to the subarctic climate zone. The species has been documented in North Asia (Caucasus, Eastern Siberia, Kamchatka, China, Korea, Japan), North America (USA, Canada), and Europe. In Europe the mushroom is distributed from Spain in the South to Macedonia in the South-East. In western Europe they can be found in France, Great Britain, in the Benelux countries and northwards to the Hebrides. They appear throughout all of middle Europe, east Europe, Ukraine, Belarus and Russia. They can also be found throughout all of Fennoscandia. In the north, its distribution area reaches Sweden and Finland, to beyond the arctic circle.
Classification
The mushroom was first classified as Agaricus confluens by Christian Hendrik Persoon in 1796. In 1828, Persoon re-classified this species under the name of Agaricus archyropus. In 1828, Elias Magnus Fries gave the mushroom the name Maramius archyropus and so put it in the genus Marasmius. Indeed, he used also the younger epithet archyropus, although the older epithet confluens through the designation took precedence. This was corrected in 1898 by P. Karsten, who gave the species the name Marasmius confluens and so used the older epithet for the classification into the genus Marasmius.
In 1871, Paul Kummer placed the mushroom as Collybia confluens in the genus Collybia and in 1898 the species was classified as Chamaeceras archyropus by Otto Kuntze in the newly-founded (by Kuntze) genus of Chamaeceras.
For a long time, the species was labelled as Collybia confluens, following Paul Kummer. This name is still in use today. In 1997, V. Antonìn, R. Halling and M. Noordeloos placed the species in the genus Gymnopus. Genetic studies show however, that Collybiopsis confluens is more closely related to Marasmiellus ramealis (type species of the genus Marasmiellus) than Gymnopus fusipes (type species of the genus Gymnopus) and therefore was classified in the genus Marasmiellus.
In 2021, the Marasmiellus-species, including Marasmiellus ramealis as former type species and Marasmiellus confluens, was transferred to the 1909-established genus Collybiopsis.
Etymology
The Latin epithet means "to flow together" or "to flow into each other".
Relevance
The mushroom is not edible, even though it likely contains no poison. Due to the tough, cartilaginous stalk and the thickness of its flesh, it is hardly used for this purpose.
References
External links
Photos of the Clustered Toughshank Mushroom
Omphalotaceae
Inedible_fungi
Fungus species | Collybiopsis confluens | [
"Biology"
] | 1,446 | [
"Fungi",
"Fungus species"
] |
72,382,255 | https://en.wikipedia.org/wiki/Avocar%C3%A9%20Island | Avocaré Island (Avoquer, Avocaire, L'Avocaire) is an island located in the St Brandon archipelago.
In the World Bank Report recommending the creation of the marine protected area of St. Brandon, Avocaré Island was classified as a Group 3 Island together with Île Raphael, L'Île Coco and L'île du Sud.
In 1846, Avocaré Island was visited by British naval officer Edward Belcher aboard HMS Samarang, who confirmed that it was then a principal fishing station with fishermen catching 102 kg of fish per day. Avocaré Island is today an uninhabited bird and turtle sanctuary. Access to the island is restricted to prevent the introduction of invasive alien species.
Key Biodiversity Area
This St. Brandon island is one of at least thirty located on the Mauritian Cargados Carajos coral reef atoll system, part of a CEPF designated Key Biodiversity Area (KBA) of the Cargados Carajos in the Southwest Indian Ocean. The Cargados Carajos are closely skirted by busy Southeast Asian shipping lanes (North and South of the Archipelago) making its unique ecosystem extremely vulnerable to a variety of risks which pose threats to its long-term existence as a Key Biodiversity Area.
St. Brandon (or the Cargados Carajos shoals) is a unique, isolated barrier reef atoll in the southwest Indian Ocean.
It is a vital habitat for endangered marine and terrestrial species and faces an existential threat from shipwrecks, illegal fishing and pollution.
St. Brandon has more than 200 km2 of reef habitat and possesses possibly one of the most biodiverse ecosystems on earth holding over 25% of known marine species when these cover less than 1% of the sea floor. In the West, there is a coral bank and a fringing reef, dominated by staghorn Acropora, classified as threatened by the US National Marine Fisheries Service in 2014. To the East of the atoll, there is a greater coral diversity including a rare species of the Pavona coral. There are persistent, but as yet unproven rumours, of the presence of rare brain corals around Avocaré Island in St. Brandon waiting to be discovered and preserved for posterity.
See also
Mascarene Islands
St Brandon
Mauritius
Île Raphael
L'île du Sud
L'île du Gouvernement
L'Île Coco
References
Ile Raphael
Outer Islands of Mauritius
Reefs of the Indian Ocean
Fishing areas of the Indian Ocean
Important Bird Areas of Mauritius
Atolls of the Indian Ocean
Marine reserves
Marine conservation
Oceanography
Fisheries science
Fisheries law
Marine protected areas
Mascarene Islands
Insular ecology
Biodiversity
Conchology
Quarantine facilities
Fly fishing
Fishing tournaments
Environment of Mauritius
Natural history of Mauritius | Avocaré Island | [
"Physics",
"Biology",
"Environmental_science"
] | 551 | [
"Oceanography",
"Hydrology",
"Applied and interdisciplinary physics",
"Biodiversity"
] |
72,383,027 | https://en.wikipedia.org/wiki/Economic%20trend | Economic trend may refer to:
all the economic indicators that are the subject of economic forecasting
see also: econometrics
general trends in the economy, see: economic history.
general trends in the academic field of economics, see: history of economics
Economics and time | Economic trend | [
"Physics"
] | 55 | [
"Spacetime",
"Economics and time",
"Physical quantities",
"Time"
] |
72,383,513 | https://en.wikipedia.org/wiki/R.M.%20B%C3%A9langer%20Ltd. | R.M. Bélanger Limited, sometimes known as Bélanger Construction, is a Canadian construction company based in Chelmsford, Ontario.
The company has completed major infrastructure projects in Ontario since it was founded in 1961.
In 2021, it was twice fined for fatal accidents at work sites that the company managed.
Organization
R.M. Bélanger Ltd is a construction company with headquarters on Radisson Avenue, Chelmsford, Ontario. It operates under the brand Bélanger Construction and is owned by Mr. Bélanger. It was founded in 1961 and specialises in the construction of commercial, industrial and institutional infrastructure. In 2008, the company employed 591 staff, and in 2009 it employed 515.
History
In 2005, the company was selected to build a student residence for Laurentian University.
In 2014, the company was fined $200,000 for federal and provincial tax evasion. The company under reported workers wages by $1.242 million in the tax years of 2008 and 2009.
In 2018, the company was awarded a $30 million contract by the City of Greater Sudbury to build the 40,000-square-foot francophone arts centre Place Des Arts.
In February 2021, R.M. Bélanger Ltd was fined $210,000 after a worker was killed while working at a Greater Sudbury golf course. In July 2021, the company was fined $175,000 following the death of a construction worker in 2019. A bridge that was under construction collapsed in Marathon, Ontario. R.M. Bélanger Ltd pled guilty to not taking every precaution reasonable, breaching the Occupational Health and Safety Act.
In 2022 R.M. Bélanger Ltd was awarded a $27.9 million construction contract to rebuild part of Algonquin Boulevard in Timmins, Ontario. The contract spans three years and includes new road surface as well as the reconstruction of the water and storm drainage.
In 2022, the company was ordered by the Canadian Nuclear Safety Commission to stop using all radiation devices following its conclusion that the company had " failed to implement a radiation protection program that includes an adequate level of management oversight of work practices and personnel qualification and training."
References
External links
Official website
1961 establishments in Ontario
Construction and civil engineering companies
Companies based in Ontario
Construction and civil engineering companies established in 1961 | R.M. Bélanger Ltd. | [
"Engineering"
] | 466 | [
"Construction and civil engineering companies",
"Civil engineering organizations"
] |
72,383,834 | https://en.wikipedia.org/wiki/Silicon%20carbide%20color%20centers | Silicon carbide color centers are point defects in the crystal lattice of silicon carbide, which are known as color centers. These color centers have multiple uses, some of which are in photonics, semiconductors, and quantum applications like metrology and quantum communication. Defects in materials have a plethora of applications, but the reason defects, or color centers in silicon carbide are significant is due to many important properties of these color centers. Silicon carbide as a material has second-order nonlinearity, as well as optical transparency and low two-photon absorption. This makes silicon carbide viable to be an alternate platform for many things, including but not limited to nanofabrication, integrated quantum photonics, and quantum systems in large-scale wafers.
Fabrication
There are mainly three methods for fabricating silicon carbide color centers. The three methods are electronic irradiation, ion injection, and femtosecond laser writing.
Electronic irradiation
This technique works by exposing the material to an electron beam that is highly ionizing. This knocks off electrons in the material itself, which generates color centers (or defects). This process however, requires a large amount of energy, having 9MeV normally being the lower limit of energy in most materials.
Ion injection
Ion injection is normally used to dope semiconductors, but it can also be used to create color centers. An ion is first accelerated to a certain energy, normally in the MeV range. This ion is then accelerated into the material, which then implants the ion into the material, changing the material composition, which can create a color center.
Femtosecond laser writing
Utilizing a nonlinear laser writing process, along with the appropriate aberration correction, defects can be generated at any depth in the crystal. This process preserves spin and optical coherence properties. The way it works is from multiphoton ionization from the femtosecond laser process. This method of fabricating defects does not only work for silicon carbide, but can also work for other materials.
Other types of fabrication for defects are neutron irradiation, proton irradiation, and focused Si beams.
Currently, new methods of fabrication are also being experimented with to try and reduce the energy used, or the complication of the process. One of the new methods is a new method of utilizing a laser writing method with a nanosecond laser.
Types of defects
There are multiple types of defects in silicon carbide, some of which are listed below:
Vsi(-) (TV1-TV3)
VsiVC(0)
DV(0)
Ky5
CAV (Carbon anti-site-vacancy pair)
SiC(D1)
NCVSi(-)
Transition metal color centers:
TI(0)
Cr3+
V(-), V(0)
Mo(0)
Er3+
Studies have been done on TV1 as a qubit, which provided a better spin-photon interface than TV2. Recently however, the role of Vsi(-) as a qubit has been full identified.
Applications
Photonics
Recently, these color centers in silicon carbide have shown promise in becoming one of the best single-photon emitters for non-classical light sources. Traditionally, attenuated lasers have been the substitute for single-photon sources. This works for quantum cryptography, but they are a partial substitute, and in the end this was not a substitute for single-photon sources as they do not produce single photons. Normally, there are two main methods of generating single photons: spontaneous parametric down-conversion and epitaxial quantum dots.
In spontaneous parametric down-conversion, single photons can be produced up to a rate of 106 photons per second. The drawback to this approach is that there is no way to generate single photons on demand. This makes this type of generation hard to use practically.
Epitaxial quantum dots are shown to generate single photons exceptionally when put under electrical pumping. This however works under very low temperatures, which also makes these applications harder to do practically in experiments.
Color centers in silicon carbide, diamonds, and other related materials would be more practical that the two other traditional approaches due to the higher temperature that they can operate at when under optical and electrical pumping.
Semiconductors
Silicon carbide is currently being used in the semiconductor industry already, due to the fact that it belongs to a family of materials called complementary metal–oxide–semiconductor compatible materials, as well as its reliability in fabrication of high-quality single crystal wafers. Since semiconductors by definition already have point defects, some may be used for purposes like single-photon sources.
Quantum properties of silicon carbide color centers
When studied at the single defect level, single emitters could be isolated. As a result of this, silicon carbide color centers can be used for applications in quantum cryptography protocols. One example of this was a study on nitrogen-vacancy centers in diamonds in 2014, which are similar to color centers in silicon carbide, that showcased novel results on how in diamonds, the nitrogen-vacancy were color centers, which also are fluorescent impurities that have many applications
Quantum entanglement between the electron spin state and the single photon quantum state occurs when two conditions are met:
The quantum state of a single photon can be correlated to the electron spin state of the silicon carbide color centers
This correlation is able to be stored in nearby nuclear spins in the color centers
This quantum entanglement allows the creation of quantum networks, which leads to quantum communications, quantum memory, and metrology.
Quantum sensing
When the color centers are first brought to an excited state, a photon can be emitted from the decay from the excited state to the ground states. This photon can then interact with other sources of static and variable magnetic fields. As a result of this, the spin transition frequency and the coherence time are altered, which then this effect is used in quantum sensing.
Comparison to diamond color centers
Much of the color center research was originally performed using diamond instead of silicon carbide. For comparison, the nitrogen-vacancy in diamond has similar quantum properties to the divacancy in silicon carbide. Diamond's vacancy potentially has better quantum properties than silicon carbide's, but one of the major benefits of silicon carbide and its color centers is increased scalability and greater ease of manufacture when compared to diamond. Additionally, silicon carbide does not suffer from complications in production such as graphitization during irradiation which is possible during diamond color center manufacture.
References
Wikipedia Student Program
Crystallographic defects | Silicon carbide color centers | [
"Chemistry",
"Materials_science",
"Engineering"
] | 1,359 | [
"Crystallographic defects",
"Crystallography",
"Materials degradation",
"Materials science"
] |
72,383,856 | https://en.wikipedia.org/wiki/Column%20groups%20and%20row%20groups | In tables and matrices, a column group or row group usually refers to a subset of columns or rows, respectively. Short names or notational names include col group or colgroup, and row group or rowgroup. They can have varying uses depending on context:
In mathematics, a partitioned matrix is an interpretation of a matrix as being broken down into submatrices which may be more precisely referred to as a collection of row groups and column groups
In web development, colgroup is a standard HTML attribute and an HTML event attribute, for example used for color formatting of entire columns in HTML tables. The colgroup tag acts as a "parent container of one or more <col> elements". Rowgroup is another HTML attribute.
In reporting (including business reporting, data reporting and financial reporting), colgroups and rowgroups can be used for constructing tables and matrices which dynamically adjusts the size of their columns and rows, respectively, by displaying the set of columns in the colgroup set (which again is a subset of the underlying data).
In reporting, colgroups and rowgroups can also be used for grouping of collapsible categories in the presentation of a table (with or without aggregation for the groups). One example of a use case may be if a table contains a lot of detailed information, but there is a want to display summarizing information of groups in the same table.
See also
Column (database)
Group by (SQL)
Row (database)
Row and column vectors in mathematics
Row and column spaces in mathematics
Table (database)
References
Matrices
Data modeling | Column groups and row groups | [
"Mathematics",
"Engineering"
] | 326 | [
"Mathematical objects",
"Matrices (mathematics)",
"Data modeling",
"Data engineering",
"Matrix stubs"
] |
72,384,904 | https://en.wikipedia.org/wiki/HD%20196737 | HD 196737, also designated as HR 7893, is a solitary orange hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.47, allowing it to be faintly visible to the naked eye. The object is located relatively close at a distance of 241 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of . At its current distance, HD 196737's brightness is diminished by 0.14 magnitudes due to interstellar dust. It has an absolute magnitude of 1.17.
This is an evolved giant star with a stellar classification of K1 III. HD 196737 is estimated to be 3.4 billion years old based on asteroseismologic measurements,enough for it to cool and expand onto the red giant branch; it is now fusing a hydrogen shell around an inert helium core. It has 1.4 time the mass of the Sun and an enlarged radius of . It radiates 43.7 times the luminosity of the Sun from its photosphere at an effective temperature of . HD 196737 has a solar metallicity — what astronomers dub chemical elements heavier than helium. The star has a projected rotational velocity too low to be measured accurately.
References
K-type giants
Microscopium
Microscopii, 13
CD-33 15119
196737
102014
7893 | HD 196737 | [
"Astronomy"
] | 293 | [
"Microscopium",
"Constellations"
] |
72,386,107 | https://en.wikipedia.org/wiki/ADB-FUBIATA | ADB-FUBIATA (AD-18, FUB-ACADB, ADB-FUBIACA) is a synthetic cannabinoid compound first identified in 2021. It is closely related in structure to the older compound ADB-FUBICA but with the amide linker group extended by the addition of a methylene bridge. It started to be sold as an ingedient in grey-market synthetic cannabis blends following the introduction of legislation in China which for the first time introduced general controls on various classes of synthetic cannabinoids, but did not encompass compounds where the linker group had been extended in this fashion. ADB-FUBIATA has many times lower affinity for cannabinoid receptors than ADB-FUBICA with an EC50 of only 635 nM at CB1, but retains full agonist activity at this target, while being practically inactive at CB2.
Legality
In the United States ADB-FUBIATA is unscheduled at the federal level as of May 22, 2023 but may be considered under the federal analogue act if sold for human consumption. North Dakota has placed ADB-FUBIATA into Schedule I on 04/27/2023.
See also
ADB-FUBHQUCA
References
Cannabinoids
Indoles
4-Fluorophenyl compounds
Amides
Carboxamides | ADB-FUBIATA | [
"Chemistry"
] | 283 | [
"Amides",
"Functional groups"
] |
72,387,233 | https://en.wikipedia.org/wiki/Abrothallus%20welwitschii | Abrothallus welwitschii is a species of lichenicolous fungus in the family Abrothallaceae. It grows on species of the foliose lichen genus Sticta. The type specimen was originally collected in Portugal in 1840 by Austrian botanist Friedrich Welwitsch, and it is after him for whom the species is named. Camille Montagne described the species in 1851, but he did not published the name validly; it was published validly by Charles Tulasne a year later.
The fungus has been collected throughout Europe, Africa (Kenya), New Zealand, South America (Chile), and northern North America. Recorded hosts have been Sticta fuliginosa, S. limbata, S. nylanderiana, and S. sylvatica.
References
welwitschii
Fungi described in 1852
Lichenicolous fungi
Taxa named by Charles Tulasne
Fungi of Africa
Fungi of South America
Fungi of North America
Fungi of New Zealand
Fungus species | Abrothallus welwitschii | [
"Biology"
] | 207 | [
"Fungi",
"Fungus species"
] |
72,387,477 | https://en.wikipedia.org/wiki/Prigogine%27s%20theorem | Prigogine's theorem is a theorem of non-equilibrium thermodynamics, originally formulated by Ilya Prigogine.
The formulation of Prigogine's theorem is:
According to this theorem, the stationary state of a linear non-equilibrium system (under conditions that prevent the achievement of an equilibrium state) corresponds to the minimum entropy production. If there are no such obstacles, then the production of entropy reaches its absolute minimum - zero. A linear system means the fulfillment of linear phenomenological relationships between thermodynamic flows and driving forces. The coefficients of proportionality in the relationships between flows and driving forces are called phenomenological coefficients.
The theorem was proved by Prigogine in 1947 from the Onsager relations. Prigogine's theorem is valid if the kinetic coefficients in the Onsager relations are constant (do not depend on driving forces and flows); for real systems, it is valid only approximately, so the minimum entropy production for a stationary state is not such a general principle as the maximum entropy for an equilibrium state. It has been experimentally established that Onsager's linear relations are valid in a fairly wide range of parameters for heat conduction and diffusion processes (for example, Fourier's law, Fick's law). For chemical reactions, the linear assumption is valid in a narrow region near the state of chemical equilibrium. The principle is also violated for systems odd with respect to time reversal.
References
External links
1977 Nobel Prize lecture by Ilya Prigogine
Attribution note: early versions of this article were translated from the Russian-language Wikipedia article on this topic.
Theorems
Thermodynamics | Prigogine's theorem | [
"Physics",
"Chemistry",
"Mathematics"
] | 350 | [
"Thermodynamics stubs",
"Physical chemistry stubs",
"Thermodynamics",
"Dynamical systems"
] |
72,387,940 | https://en.wikipedia.org/wiki/Olivia%20Sanchez%20Brown | Olivia Sanchez Brown is a multimedia Chicana artist and curator in the Los Angeles area and has been active since the early 1970s.
Art
Olivia Sanchez Brown was one of the first Chicana Artists to be featured in a juried exhibition in The Woman's Building in 1973, around the time that The Woman's Building was first established. And was included in the "Madre Tierra" exhibit in collaboration with several Chicano artists.
References
External links
American artists of Mexican descent
Living people
Year of birth missing (living people)
Artists from Los Angeles
American art curators
20th-century American women artists
21st-century American women artists
Multimedia artists
Chicana feminists | Olivia Sanchez Brown | [
"Technology"
] | 133 | [
"Multimedia",
"Multimedia artists"
] |
72,388,174 | https://en.wikipedia.org/wiki/1919%20Michigan%20Event | The 1919 Michigan Event refers to a possible meteor air burst on the evening of November 26, 1919, over far northern Indiana and southern Michigan in the United States.
Overview
Shortly before 8:00 pm (local time) on November 26, 1919, dozens of eyewitnesses throughout northern Indiana and southern Michigan reported seeing a "brilliant meteor" traveling westward toward Lake Michigan; the meteor was widely reported as both extremely colorful and producing audible sounds. The meteor was also sighted in more distant locations, including Newberry, Michigan, within the state's Upper Peninsula, Lucknow, Ontario, and across Lake Michigan in Milwaukee, Wisconsin. The shockwave from the meteor created earthquake-like tremors which caused damage to telephone lines, telegraph lines, and electrical infrastructure.
Selected eyewitness reports
William Herbert Hobbs recorded this account from Leroy Milhan, from Centreville, Michigan:
Coast Guard stations on the eastern shoreline of Lake Michigan reported the following:
Hobbs recorded this account from L. L. Hamilton from Decatur, Michigan, who was driving west of Dowagiac, Michigan:
Impact Location
Newspaper accounts in the following days widely quoted a Grand Haven, Michigan lighthouse keeper, who claimed that the meteor impacted Lake Michigan. A subsequent analysis by geologist William Herbert Hobbs, published by the Michigan Academy of Science, Arts, and Letters, suggested that these reports may have been exaggerated. Hobbs interviewed witnesses throughout Michigan and northern Indiana and determined that the majority of the meteor likely exploded in the air near Pokagon, Michigan. While Hobbs was initially optimistic about finding fragments of the meteor based on his analysis of its flight path, none were ever located.
References
Meteorite falls
Meteorites found in the United States
Michigan Event
Michigan Event
20th-century astronomical events | 1919 Michigan Event | [
"Astronomy"
] | 346 | [
"Astronomical events",
"20th-century astronomical events"
] |
72,389,171 | https://en.wikipedia.org/wiki/Eliane%20R.%20Rodrigues | Eliane Regina Rodrigues is a Brazilian applied mathematician and statistician who works in Mexico as a researcher at the Institute of Mathematics of the National Autonomous University of Mexico (UNAM). Her research involves using stochastic processes including Markov chains and Poisson point processes to model phenomena such as air pollution, noise pollution, the health effects of fat taxes, and the effectiveness of vaccination.
Education
After undergraduate study in mathematics at São Paulo State University, Rodrigues earned a master's degree in probability theory from the University of Brasília, both in Brazil. She completed a PhD in applied probability from Queen Mary and Westfield College (now Queen Mary University of London) in England.
Book
Rodrigues is the coauthor, with Brazilian mathematician Jorge Alberto Achcar, of the book Applications of Discrete-time Markov Chains and Poisson Processes to Air Pollution Modeling and Studies (Springer Briefs in Mathematics, 2013).
Recognition
Rodrigues is a member of the Mexican Academy of Sciences, and an Elected Member of the International Statistical Institute.
References
Year of birth missing (living people)
Living people
Brazilian mathematicians
Brazilian women mathematicians
Brazilian statisticians
Mexican mathematicians
Mexican women mathematicians
Mexican statisticians
Applied mathematicians
Women statisticians
São Paulo State University alumni
University of Brasília alumni
Alumni of Queen Mary University of London
Members of the Mexican Academy of Sciences
Elected Members of the International Statistical Institute | Eliane R. Rodrigues | [
"Mathematics"
] | 278 | [
"Applied mathematics",
"Applied mathematicians"
] |
72,389,614 | https://en.wikipedia.org/wiki/Xiaomi%2013 | The Xiaomi 13 is a flagship smartphone from Chinese electronics company Xiaomi, released in December 2022. It is part of the Xiaomi 13 series, which also includes the Xiaomi 13 Pro and Xiaomi 13 Lite. The device features premium build quality, advanced camera systems, and top-tier performance, catering to consumers who prioritize high-end specifications in a flagship phone.
Design and Display
The Xiaomi 13 features a sleek, modern design with a glass back or silicone polymer and aluminum frame. It is available in various colors, including Black, White, and Floral Green. The front houses a 6.36-inch AMOLED display, which offers a Full HD+ resolution (2400 x 1080 pixels), with a 120Hz refresh rate for smooth scrolling and gaming. The screen supports HDR10+ and Dolby Vision, offering vibrant colors and deep contrasts, making it ideal for multimedia consumption. The back of the Xiaomi 13 is made of a silicone polymer material in the Blue color option and glass in all other color options. Limited edition color options: Starry Sky Blue, Cabernet Orange, and Ginkgo Yellow are also made with a silicone polymer material.
Performance
Powered by the Qualcomm Snapdragon 8 Gen 2 chipset, the Xiaomi 13 provides top-tier performance in terms of processing power and energy efficiency. The phone features 8GB or 12GB of RAM, paired with 128GB, 256GB, or 512GB of UFS 4.0 storage. This hardware combination ensures smooth multitasking, fast app launches, and excellent gaming performance.
The Xiaomi 13 runs on MIUI 14, based on Android 13, offering a customizable interface, enhanced privacy features, and improved system optimizations.
Camera System
The Xiaomi 13 stands out with its triple-camera setup developed in collaboration with Leica, a renowned German camera brand. The main camera system includes:
50 MP (f/1.8) main sensor with optical image stabilization (OIS)
10 MP (f/2.0) telephoto sensor with 3.2x optical zoom
12 MP (f/2.2) ultrawide sensor with a 120° field of view
The cameras are capable of shooting 8K video at 24fps and 4K video at up to 60fps, offering impressive video capabilities for content creators. The Leica branding also brings enhanced color accuracy and an improved bokeh effect for portraits.
The front camera is a 32 MP sensor, which delivers sharp and detailed selfies, as well as excellent performance in video calls.
Battery and Charging
The Xiaomi 13 comes with a 4,500 mAh battery, supporting 67W wired fast charging, which can fully charge the device in around 38 minutes. The phone also supports 50W wireless charging, allowing for quick top-ups without the need for cables, and 10W reverse wireless charging to charge other devices.
Connectivity
The Xiaomi 13 offers 5G connectivity, ensuring fast data speeds on supported networks. It also includes Wi-Fi 6, Bluetooth 5.3, NFC, and USB Type-C. The device does not have a 3.5mm headphone jack, in line with current smartphone trends favoring wireless audio solutions.
Price and Availability
Upon launch, the Xiaomi 13 was priced competitively, offering premium flagship specifications at a relatively lower price compared to other high-end smartphones from brands like Apple and Samsung. The device is available in various global markets, including China, India, and select European countries.
Reception
The Xiaomi 13 received generally positive reviews from critics and users alike. Reviewers praised its build quality, display quality, and the performance of the camera system. The device was particularly noted for its Leica collaboration, which improved the overall photography experience. However, some critics mentioned that the MIUI software could be a bit heavy for certain users, with occasional bugs and updates being a common point of feedback.
Variants
Xiaomi 13 Pro: A more premium variant of the Xiaomi 13, with a larger display, more advanced camera system (including a 1-inch sensor), and additional features.
Xiaomi 13 Lite: A lighter, more affordable version of the 13 series, featuring a less powerful chipset and a simplified camera setup.
References
External links
- Xiaomi 13
- Xiaomi 13 Pro
- Xiaomi 13 Lite
Mobile phones introduced in 2022
Mobile phones introduced in 2023
Android (operating system) devices
13
Mobile phones with multiple rear cameras
Mobile phones with 8K video recording
Discontinued flagship smartphones | Xiaomi 13 | [
"Technology"
] | 927 | [
"Discontinued flagship smartphones",
"Flagship smartphones"
] |
72,389,705 | https://en.wikipedia.org/wiki/4-HO-MALT | 4-HO-MALT (4-hydroxy-N-methyl-N-allyltryptamine) is a tryptamine derivative which has been sold as a designer drug, first being detected in Slovenia in 2021.
See also
4-HO-MiPT
4-HO-McPT
4-HO-MPT
4-HO-NALT
4-AcO-DALT
5-MeO-MALT
References
Hydroxyarenes
Tryptamines
Tertiary amines | 4-HO-MALT | [
"Chemistry"
] | 101 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
72,390,179 | https://en.wikipedia.org/wiki/Millington%20Diamond%20engine | The Millington Diamond engine family is a series of four-stroke DOHC 16-valve straight-four cylinder racing engines, designed, developed and built by Millington Racing Engines since 1990.
References
Automobile engines
Internal combustion piston engines
Straight-four engines
Gasoline engines by model
Engines by model | Millington Diamond engine | [
"Technology"
] | 58 | [
"Engines by model",
"Engines",
"Automobile engines"
] |
72,391,184 | https://en.wikipedia.org/wiki/2%20Ursae%20Majoris | 2 Ursae Majoris (2 UMa) is an Am star in the northern circumpolar constellation of Ursa Major, located 150 light-years from the Sun. It has the Bayer designation A Ursae Majoris; 2 Ursae Majoris is the Flamsteed designation. It is visible to the naked eye as a faint white star with an apparent visual magnitude of 5.5. Currently 150 light years away, it is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.
Description
2 UMa has a stellar classification of kA3hA5mA7s, meaning it has hydrogen absorption lines typical of an A5 star, calcium K lines typical of an A3 star, and other metal absorption lines typical of an A7 star. This form of spectral type is used for Am stars, stars which show an over-abundance of metal lines in their spectrum due to slow rotation that allows stratification of elements within its photosphere. The 's' suffix indicates that the lines are sharp, another indicator of slow rotation. At an estimated age of 560 million years, 2 UMa is a main sequence star, fusing hydrogen into helium within its core. The projected rotational velocity is , very slow for a hot main sequence star.
This star has 1.9 times the mass of the Sun and 1.9 times its radius. It is radiating 11 times the Sun's luminosity from its photosphere at an effective temperature of .
Nomenclature
With π1, π2, σ1, σ2, ρ and 24 Ursae Majoris, it composed the Arabic asterism Al Ṭhibā᾽, the Gazelle. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Ṭhibā were the title for seven stars : this star as Althiba I, π1 as Althiba II, π2 as Althiba III, ρ as Althiba IV, σ1 as Althiba V, σ2 as Althiba VI, and 24 UMa as Althiba VII.
References
Ursa Major
Ursae Majoris, A
Durchmusterung objects
Ursae Majoris, 2
072037
042080
3354
Am stars
A-type main-sequence stars | 2 Ursae Majoris | [
"Astronomy"
] | 480 | [
"Ursa Major",
"Constellations"
] |
72,392,242 | https://en.wikipedia.org/wiki/Nagima%20Aitkhozhina | Nagima Abenovna Aitkhozhina (; 22 February 1946 – 10 November 2020) was a Kazakh biologist who specialised in the field of molecular biology. She was engaged in the study of the structural and functional organisation of the genome of higher organisms and the molecular mechanisms of regulation of its expression. Aitkhozhina served as general director of the Institute of Molecular Biology and Biochemistry named after M.A. Aitkhozhin of the National Academy of Sciences of the Republic of Kazakhstan from 1990 to 2018, Kazakhstan's first genome laboratory. Between 1999 and 2002, she was president of the Kazakhstan Academy of Sciences. Aitkhozhina was an elected deputy of the Congress of People's Deputies of the Soviet Union from the Committee of Soviet Women from 1989 to 1991. She was decorated with the Order of Parasat in December 2001 and the Order of the Leopard, Third Class ten years later.
Early life and education
Aitkhozhina was born in the city of Petropavl on 22 February 1946. She was a 1969 graduate of the biological faculty of Al-Farabi Kazakh National University. Following her graduation, Aitkhozhina enrolled full-time at the Engelhardt Institute of Molecular Biology of the Academy of Sciences of the Soviet Union to do her post-graduate studies in 1970. She graduated in 1973. Aitkhozhina defended her Doctor of Philosophy thesis Structural and functional organisation of nuclear RNP particles containing pro-mRNA at the university in 1974 and her Doctorate of Biological Sciences thesis called Alkaloids – inhibitors of the biosynthesis of macromolecules in 1990.
Career
Between 1973 and 1983, Aitkozhina was a junior and later senior researcher at the Botany of the Academy of Sciences of the Kazakh SSR. Following the reorganisation of the educational institute, she was then the senior and lead researcher at the Institute of Molecular Biology and Biochemistry of the Academy of Sciences of the Kazakh SSR from 1983 to 1989. Aitkhozhina was acting director of the Institute of Molecular Biology and Biochemistry between 1988 and 1990. She was a member of the Interdepartmental Scientific Council for priority areas of physical and chemical biology and biotechnology of the State Committee for Science and Technology under the Council of Ministers of the USSR, Moscow from 1987 to 1991 and was a member of the Scientific and Technical Council and expert of the projects of the All-Union programme "Priority problems of genetics" in Moscow between 1990 and 1991. Aitkohzhina was a council member of the Republican Council of Women from 1995 onwards. She was a member of the Communist Party of the Soviet Union.
She founded and served as general director of the Institute of Molecular Biology and Biochemistry named after M.A. Aitkhozhin of the National Academy of Sciences of the Republic of Kazakhstan in Alma-Ata from 1990 to 2018, Kazakhstan's first genome laboratory. From 1989 to 1991, Aitkhozhina served as an elected deputy of the Congress of People's Deputies of the Soviet Union from women's councils united by the Committee of Soviet Women, serving as a member on the Science Committee of the Supreme Soviet of the Soviet Union. She became a member of the New York Academy of Sciences in 1994 and was elected Academician-Secretary of the Department of Biological and Medical Sciences of the National Academy of Science in 1996. Aitkhozhina remained in the post until 1999. From January 1999 to April 2002, she served as president of the Kazakhstan Academy of Sciences. Aitkhozhina was an Academician at the Kazakhstan Academy of Sciences in 2003. Aitkhozhina was a member of the International Union of Biochemistry and Molecular Biology.
From 1999 to 2005, she was a member of the National Commission for Family and Women Affairs under the President of the Republic of Kazakhstan and a member of the collegium of the Ministry of Education and Science of the Republic of Kazakhstan between 1999 and 2006. Aidtkohzhina was a member of the editorial board of the Molecular Biology journal from 1996 to 2008 and was an international expert for the International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union, Brussels from 1998 to 2000. She was a member of the Higher Scientific and Technical Committee (VNTK) under the Government of the Republic of Kazakhstan from 1997 to 2003.
Between 1999 and 2013, Aitkhozhina was a member of the commission that awarded the State Prizes of the Republic of Kazakhstan in science and technology. She chaired the National Coordinating Committee of the Ministry of Environmental Protection of the Republic of Kazakhstan for the development of a framework document for the Republic of Kazakhstan on the biosafety of genetically modified organisms with Global Environment Facility support from 2003 to 2005, the Doctoral Dissertation Council at the Institute in the specialty "Molecular Biology" and "Biochemistry" between 2003 and 2010 and the National Scientific Council of the Republic of Kazakhstan on the priority of "Life Sciences" from 2011 to 2014. Between 2012 and 2015, Aitkhozhina was a member of the Supervisory Board of the PI Center for Life Sciences at Nazarbayev University.
Works
Her primary areas of scientific research were biotechnology, medical genetics, molecular biology and molecular genetics. Aitkhozhina achieved the fundamental and applied results obtained in molecular biotechnology of biomedicine and plants, ethnogenomics on the structural-functions of the genome of higher organisms of humans and plants and the molecular mechanisms of its expression regulation. For the first time, the scheme of RNA bio genesis in the nuclei of eukaryotic cells was taken as a basis and experimentally proved for the first time and it became widely employed in molecular biology and resulted in the forming of the mechanism of RNA processing in higher organisms. She organised the first genome laboratory and was successful in conducting research on the structural-functional organisation of the genome for bio medicine (genomics) for human hereditary and genetic indirect atherogenic diseases, molecular mechanisms of plant resistance to phytopathogens.
Under her leadership, the mummified materials of horses and people's remains from 2,500 years ago that were preserved in artificial frozen conditions were discovered in an archaeological dig in Berel, East Kazakhstan Region. DNA molecular genetic analysis was carried out and a comparative analysis of the DNA of different Kazakh populations was conducted, enabling further research into paleogenomics and ethnogenomics, ethnic history and ethnogenesis of people in Kazakhstan.
She was the author of 92 scientific papers, half of which were published abroad, such as the Biologically active substances of plant origin – low molecular weight bioregulators of the expression of the eukaryotic genome" that Kazakh scientists prioritised. Aitkhozhina's other primary scientific publications were Nuclear ribonucleoproteins containing messenger RNA. Nature of 5,- and 3,-terminal sequences of nuclear RNP particles in 1979, co-wrote Molecular cloning and characterization of individual representatives of the "Relic" fraction of the DNA of the Triticum timopheevii genome in 1988, Selective inhibition of the polypeptide chain elongation in eucaryotic cells in 1992 and Molecular cloning and characteristics of species – specific repetitive sequences of wheat nuclear in 1995.
Aitkhozhina also wrote Biology of cultivated wheat cells exhibited aboard the Mir space station: division, morphogenesis and differentiation in 2001, Polymorphism of the promoter region of the angiotensinogen gene and the gene for angiotensin I-converting enzyme in arterial hypertension and cardiovascular disease of the Kazakh ethnic group in 2003 and Polymorphism of noncoding region of mitochondrial genome from three populations of kazakh groups inhabited territory of Kazakhstan in 2004. She died on the evening of 10 November 2020 in Almaty.
Awards
In December 2001, she was awarded the Order of Parasat from the President of Kazkhastan, and received the Order of the Leopard, Third Class from the President in December 2011. Aitkhozhina was decorated with the Diploma of the Supreme Soviet of the Kazakh SSR, the independent Platinum Tarlan award and the Badge "For merits in the development of science of the Republic of Kazakhstan".
References
Attribution
1946 births
2020 deaths
People from Petropavl
Al-Farabi Kazakh National University alumni
20th-century Kazakhstani women
20th-century Kazakhstani people
21st-century Kazakhstani women
21st-century Kazakhstani people
Kazakhstani women scientists
Soviet women biologists
Women molecular biologists
Molecular geneticists
Medical geneticists
Women biotechnologists
Soviet women chemists
Kazakhstani women in politics
Soviet women in politics
Communist Party of the Soviet Union members
Members of the Congress of People's Deputies of the Soviet Union
Recipients of the Order of Parasat
20th-century biologists
20th-century women scientists
21st-century biologists
21st-century women scientists | Nagima Aitkhozhina | [
"Biology"
] | 1,807 | [
"Molecular geneticists",
"Biotechnologists",
"Molecular genetics",
"Women biotechnologists"
] |
72,392,562 | https://en.wikipedia.org/wiki/Ramathallus | Ramathallus is a genus of sessile lobate alga that represents a probable stem-Rhodophyte from the Upper Statherian, 1600 Million years ago. The holotype of Ramathallus lobatus shows a cell structure with finger-like protrusions and a coating of non-cellular apatic. The cells have a dark granular material inside of them. The organism grew by apical growth and possessed pseudoparenchymatous thallus which in turn infer a possible affinity with the Florideophyceae. Many lobate protrusions radiated from the organisms centre composed out of pseudoparenchymatous tissue interpreted as "Cell fountains" made up of variably-sized cells. Ramathallus shares a close morphological similarity with the Ediacaran genera made up of pseudoparenchymatous, lobate fossils (Thallophyca, Thallophycoides, Paramecia and Gremiphyca) from the Doushantuo phosphorites of China .
See also
Proterozoic
Red algae
Rafatazmia
References
Florideophyceae
Red algae
Proterozoic Asia
Prehistoric eukaryote genera
Mesoproterozoic | Ramathallus | [
"Biology"
] | 253 | [
"Red algae",
"Algae"
] |
72,392,709 | https://en.wikipedia.org/wiki/Usable%20security | Usable security is a subfield of computer science, human-computer interaction, and cybersecurity concerned with the user interface design of cybersecurity systems. In particular, usable security focuses on ensuring that the security implications of interacting with computer systems, such as via alert dialog boxes, are accessible and understandable to human users. This differs from the software engineering method of secure by design in that it emphasizes human aspects of cybersecurity rather than the technical. Usable security also sits opposite the idea of security through obscurity by working to ensure that users are aware of the security implications of their decisions.
History
Usable security was first established by Computer Scientists Jerry Saltzer and Michael Schroeder in their 1975 work The Protection of Information in Computer Systems, now colloquially referred to as Saltzer and Schroeder's design principles. The principles draw attention to 'psychological acceptability', stating that the design of an interface should match the user's mental model of the system. The authors note that security errors are likely to occur when the user's mental model and underlying system operation do not match.
Despite Saltzer and Schroeder's work, the widely-held view was, and continued to be, that security and usability were inherently in conflict; being either that security through obscurity was a preferable approach, or that user discomfort and confusion was just a requirement to ensuring good security. One such example is that of user login systems. When the user enters incorrect login details, the system must reply that the username and/or login is incorrect without clarifying which contains the incorrect value. By stating which of the inputs is incorrect (either the username or password), this could be used by an attacker to determine valid users on a system who could then be targeted by password-guessing attacks or similar exploitation. While this may cause some annoyance to the user, the approach does offer a heightened level of security.
It wouldn't be until 1995 with the publication of "User-Centered Security" by Mary Ellen Zurko and Richard T. Simon, that what is now called usable security would become a distinct field of research and design. This shift largely stems from placing greater focus on usability testing, and ensuring that security aspects are understandable during the design and development process, rather than being added as an afterthought.
Scientific conferences
While research on usable security is widely accepted by many HCI and Cyber Security conferences, dedicated venues for such work include:
EuroUSEC: European Symposium on Usable Security
HAS: International Conference on Human Aspects of Information Security, Privacy, and Trust
IFIP World Conference on Information Security Education
STAST: International Workshop on Socio-Technical Aspects in Security
TrustBus: International Conference on Trust and Privacy in Digital Business
USEC: Usable Security and Privacy Symposium
See also
Information design
Information architecture
Secure by default
Secure by design
Software Security Assurance
User-centered design
User experience design
References
Security
Human–computer interaction
Usability
Technical communication | Usable security | [
"Engineering"
] | 606 | [
"Human–computer interaction",
"Human–machine interaction"
] |
72,393,403 | https://en.wikipedia.org/wiki/Aureliano%20Chaves%20building | The Aureliano Chaves Building is a commercial building inaugurated in 2014 in Belo Horizonte, Minas Gerais, Brazil, designed by Gustavo Penna Arquiteto & Associados and Trínia Arquitetura. The building is owned by Forluz (Fundação Forluminas de Seguridade Social), a pension fund for CEMIG employees, and is currently the tallest in the city of Belo Horizonte. The building is named after Aureliano Chaves, former governor of the state of Minas Gerais and former vice-president of Brazil.
Development
The new building was proposed by Forluz with the aim of creating a new headquarters for CEMIG on a parcel next to the company's current headquarters. A closed tender was held between architecture offices in Belo Horizonte. A partnership between the Trínia Arquitetura and Gustavo Penna offices won the competition and was hired to develop the project. The competition was awarded in 2007 and the project kicked off in 2008, with approvals and construction happening over a period of 6 years. The building was inaugurated in 2014.
Architecture
The building is the first in Minas Gerais to receive the Gold rating of the LEED certification (Leadership in Energy and Environmental Design). The project was consulted by Labcon, the Thermal Comfort Laboratory of the School of Architecture at the Federal University of Minas Gerais, under the coordination of architect and professor Roberta Vieira Gonçalves de Souza. Following the shift in design towards sustainability, the construction costs of the building were increased by around 7% and yielded savings of 19% in energy consumption and 40% in water consumption.
Occupying a triangular block, the building tower is oriented in an east-west axis, with blind facades at the east and west ends - the ones which receive more intense sunlight. The north and south façades, with milder insolation, are glazed to take advantage of natural lighting, and the north façade is covered with horizontal brises soleil to soften direct solar incidence during the winter.
Throughout the LEED certification process, the initial studies for the design were evaluated with concept C in envelope, D in natural lighting and B in air conditioning, with its final rating estimated as B; following adjustments made throughout the consulting process, with various adjustments to windows, building and finishing materials, the building received the triple A rating.
Usage
CEMIG initially occupied 21 of the building's 24 floors. Following retirements and a Voluntary Separation Incentive Payment (VSIP) program carried out by the company, its headquarters building, next to the Aureliano Chaves building, were able to take in all the remaining workforce, and therefore CEMIG started to vacate parts of the new building. The pension fund that owns the building then leased four floors of the property to Banco Inter in 2019. In 2021, the bank leased the entire building, with an initial contract of 5 years.
References
Pages using the Kartographer extension
Coordinates on Wikidata
Sustainable architecture
Commercial buildings in Brazil | Aureliano Chaves building | [
"Engineering",
"Environmental_science"
] | 612 | [
"Sustainable architecture",
"Environmental social science",
"Architecture"
] |
72,395,376 | https://en.wikipedia.org/wiki/Nicotelline | Nicotelline is an alkaloid first identified in 1914 as a chemical constituent of tobacco plants (Nicotiana).
The chemical structure of nicotelline wasn't elucidated until 1956, when it was determined that nicotelline is a terpyridine consisting of three linked pyridine rings. This structure was confirmed by laboratory synthesis. Nicotelline has the molecular formula . It is a crystalline solid with a melting point of 147-148 °C. It is soluble in hot water, chloroform, ethanol, and benzene.
Nicotelline has long been known to be a constituent of tobacco smoke. As such, it has recently been proposed as a biomarker or environmental tracer for tobacco smoke.
References
Alkaloids
Pyridines | Nicotelline | [
"Chemistry"
] | 162 | [
"Organic compounds",
"Biomolecules by chemical classification",
"Natural products",
"Alkaloids"
] |
72,395,407 | https://en.wikipedia.org/wiki/C15H11N3 | The molecular formula may refer to:
Nicotelline
Terpyridine | C15H11N3 | [
"Chemistry"
] | 16 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
75,174,280 | https://en.wikipedia.org/wiki/Copper%28I%29%20azide | Copper(I) azide is an inorganic chemical compound with the formula . It is composed of a copper cation () and an azide anion ().
Properties
Copper(I) azide has been used in the preparation of high-energy materials using methods with low environmental cost. These preparations were completed using systems that were high in nitrogen and without any oxygen. Like most azides, it is explosive.
CuAAC
Copper(I) azide is supported during the process of copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC).
References
azide
copper | Copper(I) azide | [
"Chemistry"
] | 130 | [
"Explosive chemicals",
"Azides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,174,818 | https://en.wikipedia.org/wiki/Chloropentammineplatinum%20chloride | Chloropentammineplatinum chloride is an inorganic compound with the formula . It is a chloride salt of the coordination complex . It is a white, water soluble solid.
The compound is prepared by treating potassium hexachloroplatinate with aqueous ammonia:
Related platinum(IV) ammines
The title complex is one of several platinum ammine complexes.
Hexaammineplatinum(IV) chloride
Trichlorotriammineplatinum(IV) chloride
cis-Tetrachlorodiammineplatinum(IV)
trans-Tetrachlorodiammineplatinum(IV) (RN 16986-23-5)
References
Platinum complexes
Inorganic compounds
Chlorides
Chloro complexes
Octahedral compounds
Ammine complexes | Chloropentammineplatinum chloride | [
"Chemistry"
] | 160 | [
"Chlorides",
"Inorganic compounds",
"Salts"
] |
75,176,445 | https://en.wikipedia.org/wiki/Reba%20Bandyopadhyay | Reba Mithua Bandyopadhyay (born 1972) is an American science policy analyst. Formerly a professional astronomer, she works as deputy executive director of the President's Council of Advisors on Science and Technology in the US Office of Science and Technology Policy, and as legislative and science policy analyst for the National Science Board of the National Science Foundation.
Astronomy
As an astronomer, Bandyopadhyay specialized in observations of the Galactic Center and of star systems containing neutron stars and black holes. She has also participated in studies of 2060 Chiron, a Solar System object combining the characteristics of comets and asteroids.
Bandyopadhyay graduated from the Massachusetts Institute of Technology in 1993. She completed a D.Phil. in 1998 at the University of Oxford in England, with the dissertation Infrared observations of X-ray binaries supervised by Phil Charles. After postdoctoral research at the Naval Research Laboratory, she worked for the Gemini Observatory from 2001 to 2004, at the observatory's Oxford office. She then became a research scientist at the University of Florida.
Science policy
From 2014 to 2015 Bandyopadhyay was a science advisor in the United States Senate, advising Brian Schatz as an American Physical Society Congressional Fellow, and from 2015 to 2017 she worked for the National Science Board as an American Association for the Advancement of Science Science & Technology Policy Executive Branch Fellow, before taking her present positions as deputy executive director of the President's Council of Advisors on Science and Technology in the US Office of Science and Technology Policy, and as legislative and science policy analyst for the National Science Board of the National Science Foundation.
Recognition
Bandyopadhyay was elected as a Fellow of the American Association for the Advancement of Science (AAAS) in 2021, in the AAAS Section on Astronomy. She was elected as a Fellow of the American Physical Society (APS) in 2023, after a nomination from the APS Forum on Physics and Society, "for outstanding contributions to the nation through informing, crafting, and advancing innovative, inclusive, and data-driven science and technology policy".
References
1972 births
Living people
21st-century American astronomers
American women astronomers
Scientists in technology assessment and policy
Massachusetts Institute of Technology alumni
Alumni of the University of Oxford
Fellows of the American Association for the Advancement of Science
Fellows of the American Physical Society | Reba Bandyopadhyay | [
"Technology"
] | 467 | [
"Scientists in technology assessment and policy"
] |
75,177,683 | https://en.wikipedia.org/wiki/Renzo%20Rosso%20%28hydrologist%29 | Renzo Rosso (Genoa, 1950) is an Italian hydrologist recognized for his contributions to water resources and environmental engineering.
Early life and education
Renzo Rosso was born in Genoa, Italy in 1950. He attended public schools for primary education and Liceo Cassini for High school in Genoa. In 1975, he received his degree in Civil Engineering from the University of Genoa.
His father was a Jazz musician in fascist Italy and a transportation engineer in the post-war period, and following in his footsteps, Rosso learned the rudiments of classical guitar by Maestro Vercelli. He later went on to become an amateur guitarist and singer, and currently plays in a band called Figli di un Rio Minore ("Children of a Lesser River").
He has been a professor at Polytechnic University of Milan since 1986.
Major contributions
Rosso was a full professor of Hydrology and Hydraulic Constructions at Politecnico di Milano for 35 years from 1986 to 2021. Since his retirement, he has continued teaching in the Civil and Environmental Engineering Department as an adjunct professor.
His research contributions include extreme-value statistics in storm and flood hydrology, fractal river geomorphology, shallow landslides, and snow and ice hydrology of Karakoram, Himalayas. His work has influenced a great number of researchers and scholars in hydrology, hydraulics, and civil engineering: he has published over 300 papers and scientific books, and his work has been cited in over 10 thousand publications. He has also been a member of several international academic evaluation
committees at universities in Canada, US, Belgium, and Sweden.
Outside of academia, Rosso has played an influential role in Italy as a hydrology and soil preservation expert, serving in numerous committees at a national level and at a regional level, primarily in the north-western maritime region of Liguria.
He served in the Observatory for the Closure of the Nuclear Cycle in Italy (2014-2018), and previously in the Regional Technical Committee for soil conservation of the Liguria regional government and of the Civil Protection Technical Committee of the Province of Savona (1998-2008).
Between 2002 and 2008, he served as the scientific expert for the Delegate Commissioner for remediation of a former industrial site in Cengio, an area in North-West Italy which had been contaminated by decades of polluting emissions by chemical dye manufacturer Acna. In 2012, he was elected Commissioner Delegate of the Presidency of the Council of Ministers for the safety of large dams in Liguria.
As of 2023, he was President of the Environmental Control Committee for the new Genoa highway, a large-scale infrastructural project long under construction, upon nomination of the Italian Ministry for the Environment.
Rosso has also contributed to several Italian newspapers on water and climate related matters: since 2014, he has written weekly blogs on water and environmental issues for Italian daily newspaper Il Fatto Quotidiano, and he has been an editorialist for Genoa-based newspaper Il Secolo XIX.
Awards
Rosso has received several awards for his engineering and research activities.
In 2002, he received the Premio Innovazione Legambiente (2002), a yearly award by Legambiente, among Italy's foremost environmental associations.
In 2005, he won the Borland Lecture Award (2005) by the American Geophysical Union (AGU), one of the most influential associations of Earth and Space sciences worldwide.
In 2010, he was awarded the Henry Darcy Medal by the European Geosciences Union “for his fundamental contributions to hydrology and water resources management”. The medal is an annual award by the Hydrological Sciences Division of EGU, Europe's most important association in the fields of Earth, planetary, and space sciences, and is given in recognition of "outstanding scientific contributions in water resources research and water resources engineering and management".
In 2015, he was named Honorary Member of the Italian Hydrological Society, a national association promoting "the progress, enhancement, and dissemination of Hydrological Sciences" in Italy.
As of 2023, he was featured among the Top Italian Scientists under the Engineering category (101-200), a platform that ranks scientists based on their H-index, a metrics often used to measure the reach and influence of a scholar's published works.
References
Polytechnic University of Milan alumni
Hydrologists
Italian scientists
Civil engineers
Italian civil engineers
Soil scientists
1950 births
20th-century Italian scientists
21st-century Italian scientists
Living people
American Geophysical Union
European Geosciences Union | Renzo Rosso (hydrologist) | [
"Engineering",
"Environmental_science"
] | 922 | [
"Hydrology",
"Civil engineering",
"Hydrologists",
"Civil engineers"
] |
75,180,389 | https://en.wikipedia.org/wiki/Ezio%20Todini | Ezio Todini (born 5 June 1943) is an Italian academic, hydrologist and civil engineer.
Early life and education
Ezio Todini born in Lucca, Italy on 5 June 1943, spent most of his early life and youth in Cairo, Egypt. In 1969, he was awarded the degree of Doctor in Hydraulic Engineering by the University of Pisa and joined the then just inaugurated IBM Pisa Scientific Centre in 1971.
Career
In 1973, he became professor of applied hydromechanics at the University of Pisa. In 1979, he was appointed professor of water resources planning at the University of Florence. Since 1980, he has held the chair of hydrology at the University of Bologna. He retired as professor in 2010. In 2009, he was the founding president of the Italian Hydrological Society. Currently he has research collaborations with several universities and serves as water resources expert for international bodies and in particular for the World Bank.
Todini is a leading scientist in the development of hydrological modeling approaches for water resources management and planning. Since the mid-1970s, he pioneered the systems approach to hydrology and crafted a direction which guided hydrologic sciences into a new level of distributed hydrologic modelling, uncertainty quantification, and optimal parameter estimation via Kalman filtering. His Mutually Interactive State Parameter (MISP) algorithm based on an approach conceptually similar to the Gibbs sampler, introduced a novel methodology to the joint estimation of state and parameters in Kalman Filters, and served not only the hydrologic community at large but other fields of communications and environmental sciences.
In hydraulics, Todini largely contributed to the enhancement of design and simulation methods for flow in looped water distribution networks (WDN). In this context he authored the global gradient algorithm for the analysis of WDN. The algorithm is at the core of the worldwide used WDN analysis freeware EPANET. Moreover, in 2000 he introduced the resilience index, as the basis for implementing multi-objective Pareto design to WDN.
Todini initiated his research career dealing with hydrological models. Initially he proposed a quadratic programming alternative to the constrained estimation of unit hydrographs as an alternative to the linear programming approach proposed by Eagleson. The work was based on the seminal work of Norbert Wiener and Norman Levinson. This gave rise to the constrained linear systems (CLS) model, which favorably compared to the existing well known hydrological models at the WMO Project on Intercomparison of Conceptual Models Used for Hydrological Forecasting.
He also developed the ARNO hydrological model. ARNO was the first soil moisture accounting model to be included into a general circulation models (GCM) such as ECHAM GCM (Hamburg climate model). As distributed precipitation evolved, Todini developed the land surface model TOPKAPI. The model is structured around grids that capture soil and precipitation variably. He used Bayesian inference to determine flood risk based on long-term TOPKAPI simulations. The use of Bayesian inference in hydrological modelling allowed to separate out parameter and input uncertainty in operational river flow forecasting.
A major contribution to hydrology is the explanation for mass losses in flow computations on mild river bed slopes using the Muskingum-Cunge routing method and the proposition of a corrective approach for making the method mass conservative.
Another important contribution are his works on the quantification of forecasting uncertainty using multiple streamflow models through meta-Gaussian correlation-based ensemble averaging, an approach known as Model-Conditional Processor (MCP).
A major component of Todini's work has been the continuous transfer of the developed scientific approaches into operational tools to be used in the solution of real-world problems. The hydrological models, the flood routing models and the uncertainty post processors were thus integrated into operational real time flood forecasting packages installed on several rivers all around the world, such as the Po, the Arno and the Tiber in Italy, the Han Jang, the Yellow river, and the Fuchun river in China, the Duero, the Tajo, the Jucar and the Segura rivers in Spain.
He also contributed to the reference Handbook of Applied Hydrology.
Between 1984 and 1991, Todini served as vice-president of the IAHS International Commission on Water Resources Systems (ICWRS), and from 1991 to 1994 as vice-president of the IAHS. Between 2009 and 2016 he served as president the Società Idrologica Italiana – Italian Hydrological Society. From 2017 he has become the honorary president of SII-IHS.
currently he acts as Honorary President of the Italian Hydrological Society and is a member of the scientific community of the World Wildlife Fund (WWF) Italy.
References
External links
Research Gate
Living people
Hydrology
Water resources management
Decision support systems
University of Bologna
Italian engineers
1943 births | Ezio Todini | [
"Chemistry",
"Technology",
"Engineering",
"Environmental_science"
] | 982 | [
"Information systems",
"Hydrology",
"Decision support systems",
"Environmental engineering"
] |
75,180,663 | https://en.wikipedia.org/wiki/TouchHLE | touchHLE is a high-level emulator for iPhone's iOS applications, targeting early versions of the system, running them on desktop PCs and Android. Currently it supports a handful of games. The project is open source and created by a developer on the nickname hikari_no_yume.
touchHLE had its first release in February 2023 supporting the game Super Monkey Ball, an iPhone app store launch title from 2008 which was considered lost media because it didn't run on supported platforms. Latest release supports other lost media games such as Doom II RPG.
References
Emulation software
IOS | TouchHLE | [
"Technology"
] | 122 | [
"Emulation software",
"History of computing"
] |
75,180,744 | https://en.wikipedia.org/wiki/Andrei%20Khlobystov | Andrei Nikolaevich Khlobystov () is a Russian-British scientist who is the Professor of Nanomaterials at the University of Nottingham. He serves as Director for Research for the School of Chemistry in the Faculty of Science and has received several awards during his career, including the European Young Investigator award and the Corday–Morgan Prize in 2015. Khlobystov is currently the Director and principal investigator of the Metal Atoms on Surfaces and Interfaces EPSRC Programme Grant.
Early life and education
Andrei Nikolaevich Khlobystov was born in Soviet Russia in 1974. He obtained a Master of Science degree in chemistry from Moscow State University in 1997, and received a PhD in 2002 from the University of Nottingham under the supervision of Martin Schröder and Neil Champness.
Career and research
Khlobystov started his post-doctoral career at the Department of Materials at the University of Oxford from 2002 until 2004 under Andrew Briggs, where he began exploring carbon nanotube as nanoscale containers for molecules. He applied transmission electron microscopy (TEM) for imaging structures of individual molecules and studying their dynamic behaviour in direct space and real time, which shed light on intermolecular interactions, and the translation and rotational motion of molecules at nanoscale. He was part of the team awarded a Guinness World Record for performing a chemical reaction inside carbon nanotubes.
In 2004, Khlobystov moved to the University of Nottingham as a Leverhulme Trust research fellow. At Nottingham, he built the Nottingham Nanocarbon Group, which has demonstrated that nanoscale confinement can lead to new products inaccessible by other synthetic methods. In 2005, his research group was awarded a European Young Investigator award and a Royal Society University Research Fellowship. Around this time, he was featured in Times Higher Education's series of emerging researchers in the physical sciences. In 2008, the Nanocarbon Group presented at the Royal Society's Summer Science Exhibition, with a display entitled "Wonder in carbon land: how do you hold a molecule?", showcasing the potential of utilising nanocages and nanotubes to control chemical reactions. Khlobystov's team has discovered mechanisms of interactions between carbon nanostructures and molecules or nanoparticles which enabled the design of nanoreactor systems with tuneable size and functionality. This research was supported by numerous grants including a European Research Council Starting Grant in 2011.
In 2016, to commemorate the opening of the nano- and micro-Research Centre (nmRC) at the University of Nottingham, Khlobystov led a team that utilised a Focused Ion Beam Scanning Electron Microscope (FIB-SEM) to etch a birthday message onto a corgi hair to commemorate Queen Elizabeth II's 90th birthday. In 2020, Khlobystov led a team that captured a video of the chemical bond between two metal atoms breaking and forming for the first time. This followed previous work which embraced the observer effect, utilising the electron beam present in an electron microscopy to provide the source of energy to drive chemical reactions and enable them to be directly observed, and was given the moniker ChemTEM.
Since 2021, Khlobystov has been PI for the MASI programme grant, which is investigating solvent-free routes to preparing and understanding single metal atoms and metal nanoclusters on surfaces for use as catalysts for electrochemical hydrogen production, ammonia synthesis and carbon dioxide reduction.
References
Academics of the University of Nottingham
Fellows of the Royal Society of Chemistry
British materials scientists
Living people
Inorganic chemists
Academics of the University of Oxford
British physical chemists
21st-century British chemists
Alumni of the University of Nottingham
Moscow State University alumni
1974 births | Andrei Khlobystov | [
"Chemistry"
] | 752 | [
"Inorganic chemists"
] |
75,182,145 | https://en.wikipedia.org/wiki/Nickel%20azide | Nickel azide is an inorganic chemical compound with the formula . It can be formed through the reaction between nickel tetracarbonyl and iodine azide.
Properties
Nickel azide water solution has high absorbance in the ultraviolet with a peak at 292 nm. The solution also contains hexaaquanickel cations with visible light absorption peaks at 394, 656, and 720 nm. A related mixed anion compound with nicotinic acid and nicotinate exhibits EO bridging coordination (μ-1,1) on the azide, and possesses an unusual angle between the nickel and nitrogen present within the complex. Like most azides, it is explosive.
References
azide
nickel | Nickel azide | [
"Chemistry"
] | 143 | [
"Explosive chemicals",
"Azides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,182,170 | https://en.wikipedia.org/wiki/Sponge%20bomb | A sponge bomb is a specialized device designed to seal the end of a tunnel. Small enough that it can be set by a single person, it is a non-explosive, chemical bomb that releases a burst of expanding foam that quickly hardens.
Development
The sponge bomb was developed by the Israel Defense Forces (IDF) to address the use of tunnels by Hamas in Gaza.
Design
Housed in a plastic container, the bomb has a metal partition that separates two liquid reagents. Once the partition is removed, the liquids mix and react, causing them to rapidly expand and then solidify, creating a physical barrier blocking the tunnel. The device is either set at its target by an individual or thrown.
In 2021, testing of sponge bombs was reportedly conducted by IDF in simulated tunnels.
During initial testing of these bombs, the liquid emulsion was found to be hazardous to work with when mishandled – some Israeli soldiers lost their eyesight.
Historical perspective
This is not the first time that sticky foam has been used by a military force. Reportedly, the U.S. Marine Corps and the U.S. Army have used streams of foam as non-lethal tools for crowd control or restraint of hostile combatants.
References
External links
Military use of non-lethal foam (at 20 seconds into video)
Bombs of Israel
Foams
Tunnel warfare
Tunnels in Palestine
Israel–Hamas war
Israeli inventions | Sponge bomb | [
"Chemistry",
"Engineering"
] | 276 | [
"Foams",
"Military engineering",
"Tunnel warfare"
] |
75,182,697 | https://en.wikipedia.org/wiki/Norman%20F.%20Ramsey%20Prize | The Norman F. Ramsey Prize in Atomic, Molecular and Optical Physics, and in Precision Tests of Fundamental Laws and Symmetries is a prize given by the American Physical Society. It is awarded for outstanding work in the field of atomic, molecular, and optical physics, especially in the precision measurement of physical constants, tests of fundamental laws and symmetries, and precision spectroscopy. Instituted in 2016, the prize pays tribute to Nobel Laureate Norman Ramsey, celebrated for pioneering contributions such as the separated oscillatory field method and the hydrogen maser. It consists of $10,000 plus travel expenses to the annual meeting of the Division of Atomic, Molecular, and Optical Physics (DAMOP) where the prize is bestowed.
Recipients
2018: Peter Zoller
2019: Jun Ye
2020: Philip H. Bucksbaum
2021: Dmitry Budker
2022: Mikhail Lukin
2023: Olga Kocharovskaya
2024: David DeMille, Gerald Gabrielse, John Doyle
2025: Alan Kostelecký
See also
List of physics awards
List of American Physical Society prizes and awards
References
Awards of the American Physical Society | Norman F. Ramsey Prize | [
"Physics",
"Chemistry",
"Technology"
] | 226 | [
" and optical physics stubs",
"Science and technology awards",
"Science award stubs",
" molecular",
"Atomic",
"Physical chemistry stubs",
" and optical physics"
] |
75,184,216 | https://en.wikipedia.org/wiki/291%20%28number%29 | 291 is the natural number following 290 and preceding 292.
In mathematics
291 is an odd composite number with two prime factors.
291 is a semiprime number meaning that it has 2 prime factors.
291 can be written as the sum of the nth prime plus n. It is the 52nd prime (239) plus 52.
291 is one of the positions of “c” in the tribonacci word abacabaab… defined by a->ab, b->ac, c->a.
291 is the sum of six 4th powers. It is the sum of 4⁴+2⁴+2⁴+1⁴+1⁴+1⁴.
References
Integers | 291 (number) | [
"Mathematics"
] | 140 | [
"Elementary mathematics",
"Integers",
"Mathematical objects",
"Numbers"
] |
75,184,224 | https://en.wikipedia.org/wiki/Desmethylzopiclone | Desmethylzopiclone, also known as SEP-174559, is an active metabolite of the sedative-hypnotic drug zopiclone.
Pharmacology
Unlike its parent compound, which is a largely non-selective benzodiazepine receptor agonist, desmethylzopiclone is a selective partial agonist at the benzodiazepine site of α3-containing GABA receptor subtypes. It is also an antagonist to nicotinic acetylcholine receptors and NMDA receptors.
Desmethylzopiclone has been described as a potential anxio-selective metabolite of zolpiclone owing to its selective affinity for the modulation of α3-containing GABA receptor subtypes. Modulation of these GABAA subtypes have been implicated as key mediators of the anxiolytic effects of benzodiazepines.
In forensic analysis
A method for the quantification of desmethylzopiclone from urine has been developed and may serve useful in forensic analysis of cases involving zolpiclone intoxication.
References
Human drug metabolites
Carbamates
Lactams
Chloropyridines
1-Piperazinyl compounds
Pyrrolopyrazines | Desmethylzopiclone | [
"Chemistry"
] | 261 | [
"Chemicals in medicine",
"Human drug metabolites"
] |
75,184,236 | https://en.wikipedia.org/wiki/304%20%28number%29 | 304 is the natural number following 303 and preceding 305.
In mathematics
304 is an even composite number with two prime factors.
304 is the sum of consecutive primes in two different ways: It is the sum of 41+43+47+53+59+61 and of 23+29+31+37+41+43+47+53.
304 is a primitive semiperfect number meaning that it is a semiperfect number that is not divisible by any other semiperfect number.
304 is an untouchable number meaning that it is not equal to the sum of any number’s proper divisors.
304 is a nontotient number meaning that it is an even number where phi(x) cannot result in that number.
References
Integers | 304 (number) | [
"Mathematics"
] | 158 | [
"Elementary mathematics",
"Integers",
"Mathematical objects",
"Numbers"
] |
75,184,637 | https://en.wikipedia.org/wiki/Cobalt%28II%29%20azide | Cobalt(II) azide is an inorganic chemical compound with the formula . It can be formed through the reaction between dicobalt octacarbonyl and iodine azide.
Properties
Aqueous solutions of cobalt(II) azide change in color when introduced to suitable organic solvents, from pink-violet to a blue shade. Like most azides, it is explosive.
References
azide
cobalt | Cobalt(II) azide | [
"Chemistry"
] | 85 | [
"Explosive chemicals",
"Azides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,184,705 | https://en.wikipedia.org/wiki/DOM%20clobbering | In internet security, DOM clobbering (where DOM stands for Document Object Model) is a type of injection attack that revolves around the attacker being able to insert benign non-script HTML code that can be used to influence the execution of JavaScript code. This enables a skilled attacker to perform a variety of unwanted behaviours, including the ability to escalate to arbitrary code execution on the website.
While the vulnerability has been known for over a decade, recent efforts to mitigate it completely have been unsuccessful due to a significant amount of usage of the underlying features across the web as of 2021. However, a few defenses have been identified that limit the effects of DOM clobbering and prevent some instances of DOM clobbering from occurring.
Vulnerability
The DOM clobbering vulnerability arises from a naming collision between the JavaScript execution context and HTML elements in the Document Object Model (DOM). When an undefined JavaScript variable is declared in the same context as an HTML element with the same name or id parameter, the browser will assign the HTML element to the undefined variable. This behaviour can be used to selectively influence the execution of JavaScript by registering HTML elements that coincide with specific variables that affect the execution of the code. In some instances, DOM clobbering can even be used to overshadow legitimate browser APIs by shadowing the property tree using HTML DOM elements. This can lead to the attacker manipulating the execution of various parts of the JavaScript code by injecting specific markup.
A skilled attacker might be able to perform arbitrary open redirections by overwriting the window.location attribute, cross-site request forgery, or even gain arbitrary code execution via careful manipulation of HTML elements. As part of a study conducted in 2023, Khodayari et al. showed that out of the top 5K websites in the world (as determined by the Tranco list), 9.8% of sites were vulnerable to this attack, including sites like Wikibooks, GitHub, Fandom, and Trello.
History
The existence of DOM clobbering has been known since at least 2010, when a paper from researchers from University of California, Berkeley and Carnegie Mellon University demonstrated an attack where an iframe called self could be used to navigate a page to a different page, violating the same-origin policy. Over the years, security researchers have found more sophisticated techniques that have allowed for much more significant impact than what was initially demonstrated.
While the existence of the attack itself was already known, the term "DOM clobbering" itself did not emerge until 2013, when it was popularized by security researcher Gareth Heyes's blog post demonstrating how the vulnerability could be used to gain arbitrary code execution. In 2015, Heiderich et al. proposed a design for a library called JSAgents, (later DOMPurify) that would be effective at sanitizing markup injection attacks such as those related to cross-site scripting and DOM clobbering.
There has been a resurgence of interest in mitigating this attack in recent years, especially after DOM clobbering vulnerabilities were found in Gmail and Google Analytics in 2020. Over 2020 and 2021, proposals were made at various web standard groups detailing defenses against DOM clobbering by disallowing named access to DOM elements at the browser level. However, these proposals were dismissed since after investigating Chrome telemetry data, it was found that over 10.5% of the web relies on the features working as per their current behaviour.
Example
To demonstrate how a DOM clobbering attack can be used to influence JavaScript execution, the following snippet of JavaScript code is taken as an example:const url = window.globalUrlConfig || { href: '/code.js' };
const scriptElem = document.createElement('script');
scriptElem.src = url.href;
document.body.appendChild(scriptElem);In this simple example, a script element is created and subsequently rendered on the page. However, this simple example is vulnerable to DOM clobbering. An attacker can inject the following HTML via cross-site scripting or other features on the website that might allow for markup injection.<a href="https://attacker.com/malicious_script.js" id="globalUrlConfig">...</a>This injection will allow the attacker to overwrite the globalUrlConfig variable with a reference to the anchor element, which in turn overwrites the url variable and subsequently the scriptElem.src parameter, (due to the fact that url.href now refers to the href parameter of the anchor element) leading to arbitrary code execution.
Threat model
The threat model for a DOM clobbering attack is similar to that of the web attacker model proposed by Akhawe et al. in 2010. This model assumes that the attacker can send emails or, by some other method, phish the victim to specific pages under their control. The model also assumes that the attacker can inject a limited set of markup into victim websites. This can be done by leveraging other attacks such as cross-site scripting or by abusing rich text rendering features on a web page (for example, Gmail's email reader and WYSIWYG editor). This is crucial since DOM clobbering depends on the attacker being able to inject potentially benign HTML into a website.
Defenses
While the optimal defence against DOM clobbering would be to turn off access to named DOM elements, this is currently not feasible due to the significant active usage of these features as per Chrome telemetry data in 2021. However, various secure coding practices can be used to mitigate the effects of DOM clobbering on JavaScript code execution.
HTML sanitization libraries
One of the most common techniques to limit DOM clobbering attacks is to use HTML sanitization libraries. In 2017, Heiderich et al. proposed a mitigation for DOM clobbering that was subsequently added to the DOMPurify library. The mitigation leveraged the use of hashes of existing functions to determine if HTML elements had overwritten them. In addition, DOMPurify parses the id and name attributes of injected elements to identify if they can collide with existing global functions. However, recent vulnerabilities related to DOM clobbering have been found in DOMPurify and similar libraries such as HTML Janitor, which indicate that these libraries only protect against specific cases of DOM clobbering and are largely unaware of the related risks.
Content security policy
Another popular method to mitigate the effects of DOM clobbering is the use of restrictive Content Security Policies (CSP). While this does not prevent DOM clobbering from altering the execution of already present code, using restrictive content security policies can make it much harder for attackers to elevate a DOM clobbering risk into a arbitrary code execution attack by limiting how scripts can be executed on a website. By leveraging the script-src CSP directive, web developers can restrict where scripts can be loaded to a predetermined set of trusted domains. This thwarts the attacker's ability to load an untrusted attacker-controlled code significantly, if they can compromise the src attribute of a script tag.
See also
Cross-site scripting
Document Object Model
References
Citations
Sources
Further reading
Client-side web security exploits
Injection exploits | DOM clobbering | [
"Technology"
] | 1,577 | [
"Computer security exploits",
"Injection exploits"
] |
75,184,823 | https://en.wikipedia.org/wiki/History%20sniffing | History sniffing is a class of web vulnerabilities and attacks that allow a website to track a user's web browsing history activities by recording which websites a user has visited and which the user has not. This is done by leveraging long-standing information leakage issues inherent to the design of the web platform, one of the most well-known of which includes detecting CSS attribute changes in links that the user has already visited.
Despite being known about since 2002, history sniffing is still considered an unsolved problem. In 2010, researchers revealed that multiple high-profile websites had used history sniffing to identify and track users. Shortly afterwards, Mozilla and all other major web browsers implemented defences against history sniffing. However, recent research has shown that these mitigations are ineffective against specific variants of the attack and history sniffing can still occur via visited links and newer browser features.
Background
Early browsers such as Mosaic and Netscape Navigator were built on the model of the web being a set of statically linked documents known as pages. In this model, it made sense for the user to know which documents they had previously visited and which they hadn't, regardless of which document was referring to them. Mosaic, one of the earliest graphical web browsers, used purple links to show that a page had been visited and blue links to show pages that had not been visited. This paradigm stuck around and was subsequently adopted by all modern web browsers.
Over the years, the web evolved from its original model of static content towards more dynamic content. In 1995, employees at Netscape added a scripting language, Javascript, to its flagship web browser, Netscape Navigator. This addition allowed users to add interactivity to the web page via executing Javascript programs as part of the rendering process. However, this addition came with a new security problem, that of these Javascript programs being able to access each other's execution context and sensitive information about the user. As a result, shortly afterwards, Netscape Navigator introduced the same-origin policy. This security measure prevented Javascript from being able to arbitrarily access data in a different web page's execution context. However, while the same-origin policy was subsequently extended to cover a large variety of features introduced before its existence, it was never extended to cover hyperlinks since it was perceived to hurt the user's ability to browse the web. This innocuous omission would manifest into one of the well known and earliest forms of history sniffing known on the web.
History
One of the first publicly disclosed reports of a history sniffing exploit was made by Andrew Clover from Purdue University in a mailing list post on BUGTRAQ in 2002. The post detailed how a malicious website could use Javascript to determine if a given link was of a specific colour, thus revealing if the link had been previously visited. While this was initially thought of to be a theoretical exploit with little real-world value, later research by Jang et al. in 2010 revealed that high-profile websites were using this technique in the wild to reveal user browsing data. As a result multiple lawsuits were filed against the websites that were found to have used history sniffing alleging a violation of the Computer Fraud and Abuse Act of 1986.
In the same year, L. David Baron from Mozilla Corporation developed a defence against the attack that all major browsers would later adopt. The defence included restrictions against what kinds of CSS attributes could be used to style visited links. The ability to add background images and CSS transitions to links was disallowed. Additionally, visited links would be treated identically to standard links, with Javascript application programming interfaces (APIs) that allow the website to query the color of specific elements returning the same attributes for a visited link as those for non-visited links. This ensured malicious websites could not simply infer a person's browsing history by querying the colour changes.
In 2011, research by then-Stanford graduate student Jonathan Mayer found that advertising company Epic Marketplace Inc. had used history sniffing to collect information about the browsing history of users across the web. A subsequent investigation by the Federal Trade Commission (FTC) revealed that Epic Marketplace had used history sniffing code as a part of advertisements in over 24,000 web domains, including ESPN and Papa Johns. The Javascript code allowed Epic Marketplace to track if a user has visited any of over 54,000 domains. The resulting data was subsequently used by Epic Marketplace to categorize users into specific groups and serve advertisements based on the websites the user had visited. As a result of this investigation, the FTC banned Epic Marketplace Inc. from conducting any form of online advertising and marketing for twenty years and was ordered to permanently delete the data it had collected.
Threat model
The threat model of history sniffing relies on the adversary being able to direct the victim to a malicious website entirely or partially under the adversary's control. The adversary can accomplish this by compromising a previously good web page, by phishing the user to a web page allowing the adversary to load arbitrary code, or by using a malicious advertisement on an otherwise safe web page. While most history sniffing attacks do not require user interactions, specific variants of the attacks need users to interact with particular elements which can often be disguised as buttons, browser games, CAPTCHAs, and other such elements.
Modern variants
Despite being partially mitigated in 2010, history sniffing is still considered an unsolved problem. In 2011, researchers at Carnegie Mellon University showed that while the defences proposed by Mozilla were sufficient to prevent most non-interactive attacks, such as those found by Jang et al., they were ineffective against interactive attacks. By showing users overlaid letters, numbers and patterns, which would only reveal themselves if a user had visited a specific website, the researchers were able to trick 307 participants into potentially revealing their browsing history via history sniffing. This was done by presenting the activities in the form of pattern solving problems, chess games and CAPTCHAs.
In 2018, researchers at the University of California, San Diego demonstrated timing attacks that could bypass the mitigations introduced by Mozilla. By abusing the CSS paint API (which allows developers to draw a background image programmatically) and targeting the bytecode cache of the browser, the researchers were able to time the amount of time it took to paint specific links. Thus, they were able to provide probabilistic techniques for identifying visited websites.
Since 2019, multiple history sniffing attacks have been found targeting various newer features browsers provide. In 2020, Sanchez-Rola et al. demonstrated that by measuring the time a server takes to respond to a request with HTTP cookies and then comparing it to how long it took for a server to respond without cookies, a website could perform history sniffing. In 2023, Ali et al. demonstrated that newly introduced browser features could be abused also to perform history sniffing. One particularly notable example highlighted was the fact that a recently introduced feature, the Private Tokens API, introduced under Google's Privacy Sandbox initiative with an intention to prevent user tracking, could allow malicious actors to exfiltrate users browsing data by using techniques similar to those used for cross-site leak attacks.
References
Web security exploits
Internet privacy
Client-side web security exploits | History sniffing | [
"Technology"
] | 1,483 | [
"Computer security exploits",
"Web security exploits"
] |
75,185,038 | https://en.wikipedia.org/wiki/Tribute%20%28sexual%20act%29 | A tribute or cum tribute is sexual activity that involves ejaculating on the picture of someone. Originating as an online sex game, this act has gained recent coverage for its use in cyberbullying as a way to spite, intimidate a victim or achieve sexual satisfaction over them with impunity.
Definition
A tribute consists of ejaculating on a portrait, and then recording the portrait and the semen together. Tributes often circulate in dedicated online communities composed of mostly of men. Sometimes, they take the form of a video, which are known as hatewank or tribute videos depending on the context. Some tributes can feature men or random objects as targets. More commonly, the targets are women. Tributed individuals can range from celebrities, to semi-public individuals like journalists, to low-profile individuals like the tributer's partner. It can be considered as a form of fetish activity.
Origins
A 2022 Vice article frames tributes as a form bukkake-by-proxy, as both portray multiple men ejaculating on one woman. The sexual practice of bukkake originates in 1980s Japan as an alternative sex act that developed due to censorship of genitals in Japanese pornography.
Around 2006, the term was slang among porn actors. At the time, it was considered a form of online sex game. As with the general definition of tribute, the act involves the target, usually a woman, soliciting tribute images online and aims to get the most replies from men browsing.
Use in cyberbullying
Starting with the Gamergate controversy, tributes have gained notoriety as a way for male communities to spite female targets. In those contexts, the images are taken from the target's social media. Victims have described feeling guilt after being subject to tributes. Cyberbullying through tributes seeks to shame the victim into leaving social media and can be combined with other forms of harassment like doxing. Such tributes often occur in group settings with internal discussion involving mockery of the victim. The superficial homage given to such tributes conflicts with their knowingly non-consensual production. Target pictures are often taken from casual settings and casting them in an explicit way serves to cause further torment to the victim. Such media of the victims in a sexual setting often cannot practically be removed from circulation.
Motive and sociological explanation
British law professor Clare McGlynn suggests that the search for social status and the need for bonding motivates men to participate in tribute communities. Non-consensual tributes are sometimes fueled by a desire to silence or degrade women that are in public life, or to express a pro-feminist stance. Alternatively, non-consensual tributes are described as a tool to satisfy sexual or fetishistic desires with impunity.
Legal challenges
As with deepfake pornography, non-consensual tributes are considered challenging to address legally since they are often created using publicly available social media images. Some false communications offense legislation exists in the United Kingdom to address tributes. Harassment or cyberbullying often co-occurring with non-consensual tributes are easier to pursue legally. The creators of tributes often remain anonymous due to the ease of creating them. Tributes targeting minors are also difficult to track and prosecute, with local police departments declining such cases due to a lack of resources. In the United States, there is no federal legislation regulating tributes or revenge pornography, hindering enforcement of local laws across state lines.
See also
Phone sex
References
Cyberbullying
Sexual acts
Sexual harassment
Sexual slang
Online sex crimes | Tribute (sexual act) | [
"Biology"
] | 739 | [
"Sexual acts",
"Behavior",
"Sexuality",
"Mating"
] |
75,185,093 | https://en.wikipedia.org/wiki/List%20of%20fires%20in%20Egypt | This is a list of major structural fires in Egypt. It includes fires with one or more confirmed fatalities in a workplace or other public place (e.g., trains), or that result in the loss of the building.
Fire inspections and regulatory enforcement are lax in Egypt, especially since the 2011 Egyptian revolution, so large and deadly fires are somewhat more common than usual. The government of Egypt said that there were nearly 50,000 reported fires, in which 203 people died and 855 people were injured, during 2022.
21st century
20th century
Musafirkhana, 1998
Khedivial Opera House, 1971
References
Industrial fires and explosions
Egypt | List of fires in Egypt | [
"Chemistry"
] | 132 | [
"Industrial fires and explosions",
"Explosions"
] |
75,185,099 | https://en.wikipedia.org/wiki/Chromium%20azide | Chromium azide is an inorganic chemical compound with the formula .
Properties
Chromium azide formation has been investigated from chromium salts and sodium azide. It was separated in 1922 through the evaporation of a dry crystalline chromium(III) nitrate solution in absolute alcohol with sodium azide. Through a spectrophotometric study, it was shown that the chromium(III) nitrate solution's green color was due to the mono-azido-chromium(III) complex. Two absorbency maxima were located at 442 and 605 nm. Chromium azide has luminescence properties from its optically active Cr3+ ions.
References
azide
chromium | Chromium azide | [
"Chemistry"
] | 151 | [
"Explosive chemicals",
"Azides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,185,459 | https://en.wikipedia.org/wiki/Interdigitation | Interdigitation is the interlinking of biological components that resembles the fingers of two hands being locked together. It can be a naturally occurring or man-made state.
Examples
Naturally occurring interdigitation includes skull sutures that develop during periods of brain growth, and which remain thin and straight, and later develop complex fractal interdigitations that provide interlocking strength. A layer of the retina where photoreception occurs is called the interdigitation zone. Adhesion or diffusive bonding occurs when sections of polymer chains from one surface interdigitate with those of an adjacent surface. In the dermis, dermal papillae (DP) (singular papilla, diminutive of Latin papula, 'pimple') are small, nipple-like extensions of the dermis into the epidermis, also known as interdigitations. The distal convoluted tubule (DCT), a portion of kidney nephron, can be recognized by several distinct features, including lateral membrane interdigitations with neighboring cells.
Some hypotheses contend that crown shyness, the interdigitation of canopy branches, leads to "reciprocal pruning" of adjacent trees.
Interdigitation is also found in biological research. Interdigitation fusion is a method of preparing calcium- and phosphate-loaded liposomes. Drugs inserted in the bilayer biomembrane may influence the lateral organization of the lipid membrane, with interdigitation of the membrane to fill volume voids. A similar interdigitation process involves investigating dissipative particle dynamics (DPD) simulations by adding alcohol molecules to the bilayers of double-tail lipids. Pressure-induced interdigitation is used to study hydrostatic pressure of bicellular dispersions containing anionic lipids.
References
Morphology (biology)
Research | Interdigitation | [
"Biology"
] | 396 | [
"Morphology (biology)"
] |
75,185,887 | https://en.wikipedia.org/wiki/VT%201137-0337 | VT 1137-0337 is a extragalactic pulsar wind nebula (possibly a magnetar nebula) that is located 395 million light years away from planet earth in the dwarf galaxy named SDSS J113706.18-033737.1, a galaxy going through a burst of star formation. It was created through the supernova of a massive star just 14-80 years ago.
Formation
VT 1137-0337 was formed 14 to 80 years ago when a massive star went supernova leaving behind a supernova remnant and a young pulsar type fast spinning neutron star.
Neutron star
The neutron star left at the center of VT 1137-0337 is fast spinning pulsar type neutron star that has a strong magnetic field creating charged particles travelling at the speed of light in the surrounding space creating a strong radio emission.
Discovery
The nebula VT 1137-0337 was spotted by using the Very Large Array Sky Survey (also called VLASS).
References
Pulsar wind nebulae
Leo (constellation)
Astronomical objects discovered in 2022 | VT 1137-0337 | [
"Astronomy"
] | 217 | [
"Leo (constellation)",
"Constellations"
] |
75,185,974 | https://en.wikipedia.org/wiki/Tremella%20rubromaculata | Tremella rubromaculata is a species of fungus in the family Tremellaceae. It produces reddish orange, lobed, gelatinous basidiocarps (fruit bodies) and is parasitic on other fungi on dead branches of broad-leaved trees. It was originally described from Guatemala.
Taxonomy
Tremella rubromaculata was first published in 1964 by American mycologist Bernard Lowy based on a collection made in Guatemala.
Description
Fruit bodies are gelatinous, bright reddish orange, up to 2.5 cm (1 in) across, and lobed. Microscopically, the basidia are tremelloid (ellipsoid, with oblique to vertical septa), 4-celled, 17 to 21 by 8 to 11 μm. The basidiospores are ellipsoid, smooth, 8 to 10.5 by 6 to 8 μm.
Similar species
Tremella dysenterica, described from Brazil, is bi-coloured (yellow and reddish orange) and similarly lobed to subfrondose, but has smaller basidia and smaller spores (5.5 to 8.5 by 4 to 5.5 μm). Elsewhere, Tremella erythrina is similarly coloured, but only known from China.
Habitat and distribution
Tremella rubromaculata is a parasite on lignicolous fungi, but its host species is unknown. It is found on dead, attached or fallen branches of broad-leaved trees.
The species was described from Guatemala and has also been reported from Brazil and Mexico.
References
rubromaculata
Fungi of Central America
Fungi of South America
Fungi described in 1964
Parasitic fungi
Fungus species | Tremella rubromaculata | [
"Biology"
] | 347 | [
"Fungi",
"Fungus species"
] |
75,186,031 | https://en.wikipedia.org/wiki/SDSS%20J113706.18-033737.1 | SDSS J113706.18-033737.1 (PGC 125758) is a dwarf starburst galaxy with a mass of 100 times the mass of the sun. This galaxy is located 395 million light years away from earth. It is currently undergoing a burst of stellar formation forming 0.5 solar masses a year.
Reference
Dwarf galaxies
Starburst galaxies
125758
Leo (constellation) | SDSS J113706.18-033737.1 | [
"Astronomy"
] | 87 | [
"Galaxy stubs",
"Leo (constellation)",
"Astronomy stubs",
"Constellations"
] |
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