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74,457,726 | https://en.wikipedia.org/wiki/Leucocoprinus%20minimus | Leucocoprinus minimus is a species of mushroom-producing fungus in the family Agaricaceae.
Taxonomy
It was first described in 1852 by the British mycologist Miles Joseph Berkeley who classified it as Hiatula minima.
In 1916, it was reclassified as Leptomyces minimus by the American mycologist William Murrill.
This was reclassified as Lepiota minima in 1952 by the British mycologist Richard William George Dennis and then as Leucocoprinus minimus in 1981 by the British mycologist David Pegler.
Description
Leucocoprinus minimus is a small dapperling mushroom with very thin white flesh that becomes pink and deliquesces with age.
Cap: 2–3 cm wide. Hemispherical with a flat umbo. The surface is white and dotted with tiny dark purple-brown scales which are denser at the centre disc. It has striations (plicato-striate) running from the cap margins halfway to the centre of the cap. Stem: 2mm thick and equal in width across the length however no length is provided in Dennis' description. It is smooth, hollow and curved with a white surface that becomes purple-brown at the base. Gills: Thin, equal, crowded and remote from the stem. They are about 2mm wide. No colour is provided in the description. Spores: 6–10 × 5–7 μm. Elliptical and hyaline. They have a red amyloid reaction when mounted in Melzer's reagent. Basidia: 4 spored.
Pegler provides more detail on the spores:
Spores: 7–9 × 5.5–6 μm. Ovoid to ellipsoid with a truncated, conspicuous apical germ pore. Dextrinoid.
Pegler also notes that the species is fragile and lacks an annulus on the stem when mature but does not otherwise add to the description.
Habitat and distribution
L. minimus is scarcely recorded and little known. The specimens studied by Berkeley were collected in Santo Domingo by M. Augustus Sallé. Murrill stated that the specimens were only known from this location. Dennis made his study based on specimens collected in the Trinidad where they were found growing gregariously on stumps in the forest. Pegler details a specimen collected on Santa Cruz Island in the Galápagos where they were found in the Miconia zone of the island on mossy roots amongst leaf litter.
Etymology
The specific epithet minimus (originally minima) is Latin for 'smallest'.
References
minimus
Fungi described in 1852
Fungus species
Fungi of North America | Leucocoprinus minimus | [
"Biology"
] | 541 | [
"Fungi",
"Fungus species"
] |
74,457,964 | https://en.wikipedia.org/wiki/Leucocoprinus%20pepinosporus | Leucocoprinus pepinosporus is a species of mushroom-producing fungus in the family Agaricaceae.
Taxonomy
It was first described in 1977 by the Belgian mycologist Paul Heinemann who classified it as Leucocoprinus pepinosporus.
Description
Leucocoprinus pepinosporus is a small dapperling mushroom. The description given by Heinemann is scant and does not provide much detail.
Cap: The surface is white with greyish-brown scales in the centre disc. The cap is submembranous with striated edges. No dimensions are provided in the description. Stem: It has a thick base and a fragile ring but no other details are provided. The colour is described as 'white then pink' but it is unclear if this is referring to pink discolouration with age, bruising or different colouration across the stem surface as it also says white stem flesh and pink below the cap. Spores: 11.2–13.5 x 7.4–8.1 μm. Amygdaliform with apical elongation but no germ pore. Cheilocystidia: 45–50 x 14–20 (28) μm. Lanceolate.
Habitat and distribution
L. pepinosporus is scarcely recorded and little known. The specimens studied by Heinemann were found growing in Zaire, now the Democratic Republic of the Congo. They were collected in Panzi, in the region of Lake Edward and Lake Kivu.
References
pepinosporus
Fungi described in 1977
Fungus species
Fungi of Africa | Leucocoprinus pepinosporus | [
"Biology"
] | 325 | [
"Fungi",
"Fungus species"
] |
74,462,180 | https://en.wikipedia.org/wiki/Simulator%20pedal | A simulator pedal, sim pedal or gaming pedal is a pedal used in a simulator for entertainment or training. Common examples are throttle and brake pedals for driving simulators, and rudder pedals for flight simulators. For minimum latency, they are often connected to a computer or gaming console via cabling, for example with USB-C.
For video game entertainment such as arcade games or for beginner sim racers, inexpensive pedals are often used, while for serious training and professional sim racing there are more expensive models, and these are sometimes coupled with a direct-drive sim racing wheel.
Although new sim racers are often more concerned with the steering wheel, many experienced racers recommend putting more money into the pedals (and a sturdy sim rig) and rather purchase a less expensive steering wheel if one has to prioritize.
Sensors
The transducer or sensor on inexpensive pedals is often based on potentiometers eller Hall effect sensors, while more expensive pedals use load cells (or sometimes load cells combined with hydraulics). Gaming pedals used with computer games are basically electronic brake-by-wire pedals and electronic throttle-by-wire pedals.
Mechanics
The pedals can be designed with complex geometries consisting of arms, springs and dampers with the intention of creating a "natural" feel with progressive and repeatable resistance so that the driver can perform more consistently in competitions. This is particularly important for the brake pedal in sim racing. For some affordable pedals, there are upgrade kits and homemade solutions available with the aim of imitating the feeling one can get with more expensive pedals.
Haptics
In 2022, the Finnish company Simucube launched ActivePedal, the world's first mass-produced simpedal with haptic technology. Co-founder and technical director Tero Kontkanen from Simucube claims that such active pedals in the long run will have a greater impact on sim racing than direct-driven sim racing wheels.
Haptic pedals can be used to give the driver of a car simulator valuable feedback (in the form of force-feedback and vibrators) based on telemetry from what happens to the car's tires against the ground in the simulator. Haptics are primarily useful for the brake pedal. In addition to giving the ability to sense the transition from static to kinetic friction when skidding, haptic pedals can also be used to simulate pulsations in the pedals of cars with anti-lock brakes or traction control.
Automotive pedals
The most common sim racing pedal setup is two asymmetric pedals with a brake pedal and an accelerator pedal. A clutch pedal can often be purchased separately as an optional extra, and can, for example, be relevant the driver desires to realistically drive historic racing cars with a manual gear stick. Some inexpensive pedal kits come with three pedals, and some sim steering wheel bundles also come with pedals included. A clutch pedal is rarely necessary in sim racing.
In case the seat and cockpit setup is to mimic a close to lying Formula style seating position it can be beneficial to be able to mount the pedals inverted such that the pedals hang downwards instead of coming up from the floor as normal. Many pedals can easily be inverted by mounting them upside down, but not all pedal sets can be inverted. As for the more common upright GT style seating position, which is more comfortable for longer sessions and therefore will be more relevant for most drivers, it is of less importance whether the pedal can be inverted or not.
Flight pedals
Rudder pedals for flight simulators simulate rudder control (and possibly toe brakes), and come in pairs with one pedal for each foot. The pedals are interconnected and synchronized so that one pedal flips out when the other is pressed in.
Bicycle pedals
There are indoor exercise bikes that can be used for computer games. Alternatively, some bicycle trainers have sensors to measure the rider's performance, including power (watts), cadence(r/min), virtual speed and heart rate, and these measurements can be connected to software or apps so that one can compete against oneself in a cycling game or against other riders over the internet. Analysis of the measurements can also help with the cyclist's training.
See also
Esports
Gaming chair
Joystick or yoke
Rudder pedals, a foot-operated interface for steering the rudder of an airplane
Sim racing wheel
Throttle pedal or throttle lever
References
Game controllers
Computer peripherals | Simulator pedal | [
"Technology"
] | 911 | [
"Computer peripherals",
"Components"
] |
74,462,933 | https://en.wikipedia.org/wiki/Pydiflumetofen | Pydiflumetofen belongs to the large family of SDHI pesticides, it is used as broad spectrum fungicide in agriculture to protect crops from fungal diseases. It was first marketed by Syngenta in 2016 using their brand name Miravis. The compound is an amide which combines a pyrazole acid with a substituted phenethylamine to give an inhibitor of succinate dehydrogenase, an enzyme that inhibits cellular respiration in almost all living organisms.
History
Inhibition of succinate dehydrogenase, the complex II in the mitochondrial respiration chain, has been known as a fungicidal mechanism of action since the first examples were marketed in the 1960s. The first compound in this class was carboxin, which had a narrow spectrum of useful biological activity, mainly on basidiomycetes and was used as a seed treatment. By 2016, at least 17 further examples of this mechanism of action were developed by crop protection companies, with the market leader being boscalid, owing to its broader spectrum of fungal species controlled. However, it lacked full control of important cereal diseases, especially septoria leaf blotch Zymoseptoria tritici.
A group of compounds which did control septoria were amides of pyrazole-4-carboxylic acid, with the most successful being derivatives with an N-methyl group and a difluromethyl group in position 3 of the ring. These include penthiopyrad and fluxapyroxad. Research chemists at Syngenta made many analogues of this type in the search for new products and by 2008 had discovered benzovindiflupyr, isopyrazam, sedaxane and pydiflumetofen.
Synthesis
Pydiflumetofen combines 3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid with a novel amine derivative which was made from 2,4,6-trichlorobenzaldehyde.
A nitrostyrene is formed in a Henry reaction between the aldehyde and nitroethane. A reduction reaction converts it to a ketone which forms an imine with methoxyamine. This, in turn, is reduced with sodium cyanoborohydride to give the amine required for amide formation with the acid chloride of the pyrazole.
Mechanism of action
Succinate dehydrogenase inhibitors (SDHI) of this type act by binding at the quinone reduction site of the enzyme complex, preventing ubiquinone from doing so. As a consequence, the tricarboxylic acid cycle and electron transport chain cannot function.
Usage
Pydiflumetofen has fungicidal effects against a wide range of crop pests. These include Alternaria, grey mould (Botrytis cinerea), Cercospora (leaf spot), septoria, powdery mildews (e.g. Uncinula necator), and scab (e.g. Venturia pyrina). As a result, it has potential use in crops including cereals, corn, soybeans, vegetables, peanut, curcubits, potato and fruit.
The compound was introduced in the US in 2018 but estimated usage that year was low at only . The compound is registered for use on peanut and fruits. the compound is also registered in Argentina, Australia, Canada and New Zealand.
Human safety
Pydiflumetofen has low acute toxicity: the Codex Alimentarius database maintained by the FAO lists the maximum residue limits for it in various food products.
Environmental effects
The compound is very persistent in field conditions and its environmental fate and consequent ecotoxicology have been reviewed. In one laboratory study, the R enantiomer of the compound was shown to be more toxic to zebrafish, which was interpreted to be owing to its higher potency as an SDHI inhibitor than the S isomer.
Resistance management
Fungal populations have the ability to develop resistance to SDHI inhibitors. This potential can be mitigated by careful management. Reports of individual pest species becoming resistant are monitored by manufacturers, regulatory bodies such as the EPA and the Fungicides Resistance Action Committee (FRAC). The risks of resistance developing can be reduced by using a mixture of two or more fungicides which each have activity on relevant pests but with unrelated mechanisms of action. FRAC assigns fungicides into classes so as to facilitate this.
Brands
Pydiflumetofen is the ISO common name for the active ingredient which is formulated into the branded product sold to end-users. Miravis is the brand name for Syngenta's suspension concentrate, which it also calls Adepidyn technology. The Miravis brand line includes other products containing pydiflumetofen mixed with other fungicidal active ingredients. These include Miravis Duo and Miravis Top (containing difenoconazole), Miravis Neo (containing propiconazole and azoxystrobin), and Miravis SBX (containing difenoconazole and azoxystrobin).
Trebuset is the brand name for Syngenta's flowable concentrate formulation for use as a seed treatment.
References
Further reading
External links
PPDB pesticides properties database entry for pydiflumetofen
Fungicides
Difluoromethyl compounds
Pyrazolecarboxamides
Phenethylamines
Chloroarenes
Methoxy compounds | Pydiflumetofen | [
"Biology"
] | 1,151 | [
"Fungicides",
"Biocides"
] |
74,465,682 | https://en.wikipedia.org/wiki/Hawking%20Fellowship | The Professor Stephen Hawking Fellowship is a prestigious annual fellowship of the Cambridge Union Society in the University of Cambridge. Awarded to an individual who has made an exceptional contribution to the STEM fields and social discourse, it is unique amongst comparable accolades in that it is conferred by the students of the University (through the Union), rather than the University itself.
Established to celebrate Hawking’s achievements and the close relationship between him and the students of Cambridge, Professor Hawking accepted the inaugural fellowship and delivered the lecture in his last public appearance before his passing. Each honouree visits the Union to commence their tenure as fellow, delivering what is known as ‘The Hawking Lecture’.
Past Fellows
References
Science and technology awards | Hawking Fellowship | [
"Technology"
] | 143 | [
"Science and technology awards"
] |
74,467,809 | https://en.wikipedia.org/wiki/Terephthalaldehyde | Terephthalaldehyde (TA) is an organic compound with the formula C6H4(CHO)2. It is one of three isomers of benzene dicarboxaldehyde, in which the aldehyde moieties are positioned in the para conformation on the benzene ring. Terephthalaldehyde appears as a white to beige solid, typically in the form of a powder. It is soluble in many organic solvents, such as alcohols (e.g., methanol or ethanol) and ethers (e.g., tetrahydrofuran or diethylether).
Preparation
Terepthalaldehyde can be synthesised from p-xylene in two steps. First, p-xylene can be reacted with bromine to create α,α,α',α'-Tetrabromo-p-xylene. Next, sulphuric acid is introduced to create terephthaldehyde. Alternative procedures also describe the conversion of similar p-xylene derivatives into terephthalaldehyde.
Reactions and applications
Terphthalaldehyde is used in the preparation of imines, which are also commonly referred to as Schiff bases, following a condensation reaction with amines. During this reaction, water is also formed. This reaction is by definition reversible, thus creating an equilibrium between aldehyde and amine on one side, and the imine and water on the other. However, due to aromatic conjugation between the imine group and benzene ring, the imines are relatively stable and will not easily hydrolyse back to the aldehyde. When in an acidic aqueous environment, however, imines will start to hydrolyse more easily. Typically, an equilibrium between the imine and aldehyde is formed, which is dependent on the concentration of the relevant compounds and the pH of the solution.
Imines from terephthalaldehyde find use in the preparation of metal-organic coordination complexes. In addition, terepthaldehyde is a commonly used monomer in the production of imine polymers, also called polyimines. It finds further use in the synthesis of covalent organic frameworks (COFs), and It is used as a precursor for the preparation of paramagnetic microporous polymeric organic frameworks (POFs) through copolymerization with pyrrole, indole, and carbazole. Due to the characteristic metal-coordinating properties of imines, terephthalaldehyde finds common use in synthesis of molecular cages.
Terephthalaldehyde is also a commonly used intermediate or starting material in the preparation of a broad variety of organic compounds, such as pharmaceuticals, dyes and fluorescent whitening agents.
Related compounds
phthalaldehyde
isophthalaldehyde
terephthalic acid
References
Benzaldehydes
Monomers
Reagents for organic chemistry | Terephthalaldehyde | [
"Chemistry",
"Materials_science"
] | 624 | [
"Monomers",
"Polymer chemistry",
"Reagents for organic chemistry"
] |
74,468,491 | https://en.wikipedia.org/wiki/Parasites%20and%20pathogens%20of%20wolves | Wolves may suffer from various pathogens, both viral and bacterial, and parasite, both external and internal. Parasitic infection in wolves is of particular concern to people. Wolves can spread them to dogs, which in turn can carry the parasites to humans. In areas where wolves inhabit pastoral areas, the parasites can be spread to livestock.
Diseases
Viral
Viral diseases carried by wolves include: rabies, canine distemper, canine parvovirus, infectious canine hepatitis, papillomatosis, and canine coronavirus. Wolves are a major host for rabies in Russia, Iran, Afghanistan, Iraq and India. In wolves, the incubation period is eight to 21 days, and results in the host becoming agitated, deserting its pack, and travelling up to a day, thus increasing the risk of infecting other wolves. Infected wolves do not show any fear of humans, most documented wolf attacks on people being attributed to rabid animals. Although canine distemper is lethal in dogs, it has not been recorded to kill wolves, except in Canada and Alaska. The canine parvovirus, which causes death by dehydration, electrolyte imbalance, and endotoxic shock or sepsis, is largely survivable in wolves, but can be lethal to pups. Wolves may catch infectious canine hepatitis from dogs, though there are no records of wolves dying from it. Papillomatosis has been recorded only once in wolves, and likely does not cause serious illness or death, though it may alter feeding behaviours. The canine coronavirus has been recorded in Alaskan wolves, infections being most prevalent in winter months.
Bacterial
Bacterial diseases carried by wolves include: brucellosis, Lyme disease, leptospirosis, tularemia, bovine tuberculosis, listeriosis and anthrax. Wolves can catch Brucella suis from wild and domestic reindeer. While adult wolves tend not to show any clinical signs, it can severely weaken the pups of infected females. Although lyme disease can debilitate individual wolves, it does not appear to significantly affect wolf populations. Leptospirosis can be contracted through contact with infected prey or urine, and can cause fever, anorexia, vomiting, anemia, hematuria, icterus, and death. Wolves living near farms are more vulnerable to the disease than those living in the wilderness, probably because of prolonged contact with infected domestic animal waste. Wolves may catch tularemia from lagomorph prey, though its effect on wolves is unknown. Although bovine tuberculosis is not considered a major threat to wolves, it has been recorded to have killed two wolf pups in Canada.
Parasitic
Wolves carry ectoparasites and endoparasites; those in the former Soviet Union have been recorded to carry at least 50 species. Most of these parasites infect wolves without adverse effects, though the effects may become more serious in sick or malnourished specimens.
Extoparasites
Wolves are often infested with a variety of arthropod exoparasites, including fleas, ticks, lice, and mites. The most harmful to wolves, particularly pups, is the mange mite (Sarcoptes scabiei), though they rarely develop full-blown mange, unlike foxes. Lice, such as Trichodectes canis, may cause sickness in wolves, but rarely death. Ticks of the genus Ixodes can infect wolves with Lyme disease and Rocky Mountain spotted fever. The tick Dermacentor pictus also infests wolves. Other ectoparasites include chewing lice, sucking lice and the fleas Pulex irritans and Ctenocephalides canis.
Endopatasites
Endoparasites known to infect wolves include: protozoans and helminths (flukes, tapeworms, roundworms and thorny-headed worms). Of 30,000 protozoan species, only a few have been recorded to infect wolves: Isospora, Toxoplasma, Sarcocystis, Babesia, and Giardia. Some wolves carry Neospora caninum, which can be spread to cattle and is correlated with bovine miscarriages.
Among flukes, the most common in North American wolves is Alaria, which infects small rodents and amphibians which are eaten by wolves. Upon reaching maturity, Alaria migrates to the wolf's intestine, but does little harm. Metorchis conjunctus, which enters wolves through eating fish, infects the wolf's liver or gall bladder, causing liver disease, inflammation of the pancreas, and emaciation. Most other fluke species reside in the wolf's intestine, though Paragonimus westermani lives in the lungs. Tapeworms are commonly found in wolves, as their primary hosts are ungulates, small mammals, and fish, which wolves feed upon. Tapeworms generally cause little harm in wolves, though this depends on the number and size of the parasites, and the sensitivity of the host. Symptoms often include constipation, toxic and allergic reactions, irritation of the intestinal mucosa, and malnutrition. Infections by the tapeworm Echinococcus granulosus in ungulate populations tend to increase in areas with high wolf densities, as wolves can shed Echinoccocus eggs in their feces onto grazing areas.
Wolves can carry over 30 roundworm species, though most roundworm infections appear benign, depending on the number of worms and the age of the host. Ancylostoma caninum attaches itself on the intestinal wall to feed on the host's blood, and can cause hyperchromic anemia, emaciation, diarrhea, and possibly death. Toxocara canis, a hookworm known to infect wolf pups in the uterus, can cause intestinal irritation, bloating, vomiting, and diarrhea. Wolves may catch Dioctophyma renale from minks, which infects the kidneys, and can grow to lengths of . D. renale causes the complete destruction of the kidney's functional tissue and can be fatal if both kidneys are infected. Wolves can tolerate low levels of Dirofilaria immitis for many years without showing any ill effects, though high levels can kill wolves through cardiac enlargement and congestive hepatopathy. Wolves probably become infected with Trichinella spiralis by eating infected ungulates. Although T. spiralis is not known to produce clinical signs in wolves, it can cause emaciation, salivation, and crippling muscle pains in dogs. Thorny-headed worms rarely infect wolves, though three species have been identified in Russian wolves: Nicolla skrjabini, Macracanthorhynchus catulinus, and Moniliformis moniliformis.
See also
Dog health
List of dog diseases
References
Bibliography
Wolves
Parasitism | Parasites and pathogens of wolves | [
"Biology"
] | 1,465 | [
"Parasitism",
"Symbiosis"
] |
69,903,455 | https://en.wikipedia.org/wiki/Kelsey%20Hightower | Kelsey Hightower (born February 27, 1981) is an American software engineer, developer advocate, and speaker known for his work with Kubernetes, open-source software, and cloud computing.
Early life and education
Hightower grew up in Long Beach, California, then moved to Atlanta, Georgia with his mother as he was beginning high school. After high school he enrolled at Clayton State University, but found the technology courses to be lacking and didn't continue. He then began courses to earn his CompTIA A+ information technology (IT) certification.
Career
When Hightower was 19 years old, after earning his CompTIA A+ certification, he got a job with BellSouth installing DSL service. He continued to work with BellSouth for several years, then began his own IT consultancy. He hired several others, and ultimately opened a store in Jonesboro, Georgia. Also in his early career, Hightower briefly worked as a technician for Google, then at Total Systems (now called TSYS).
Hightower began to give talks at Python meetups in Atlanta, where he was noticed by James Turnbull for how he and his colleagues were using Puppet, Python, and their own code to manage and automate deploys. In 2013, Puppet, Inc. invited Hightower to speak at their headquarters for a developer event, and then offered Hightower a job as a software engineer. Hightower began working for Puppet remotely from Atlanta, then moved to Portland, Oregon to work from their headquarters. Meanwhile, Hightower learned about technologies including Go and Docker containers, which he believed would be transformative to software infrastructure.
Hightower then briefly worked at a small Portland startup called Monsoon Commerce, at which he wrote , his first open-source project. He joined CoreOS as an early team member towards the beginning of 2014, and began to contribute significantly to the Kubernetes project.
Since November 2015, Hightower has worked for Google as an engineer and developer advocate in their cloud computing division. , Hightower is a distinguished engineer, level 9 (L9) as an individual contributor, with Google Cloud.
On June 26, 2023, Hightower announced his retirement from Google on Twitter, stating, among other things that "if everything goes to plan, then this is the last job [he'll] ever have."
Open source and developer advocacy
In 2014, while working for CoreOS, Hightower became an active evangelist of Kubernetes, and began to speak widely on the topic at developer conferences. He has since become one of the most well-known speakers on Kubernetes, and has also spoken on other topics, including serverless computing. In 2015, he co-founded the Kubernetes-focused conference KubeCon, which he then turned over to be managed by the Cloud Native Computing Foundation in subsequent years.
In 2017, he co-wrote a book with Kubernetes co-founders Joe Beda and Brendan Burns, titled Kubernetes Up and Running.
In 2019, Hightower was co-chair of the O'Reilly Open Source Convention and on the governing board of the Cloud Native Computing Foundation.
Publications
See also
Ian Coldwater
Brad Fitzpatrick
References
1981 births
21st-century African-American writers
21st-century American male writers
21st-century American writers
African-American computer scientists
American computer scientists
American software engineers
Google employees
Living people
Open source advocates
People from Atlanta
People from Long Beach, California
People from Portland, Oregon
People in information technology
Technology evangelists | Kelsey Hightower | [
"Technology"
] | 710 | [
"People in information technology",
"Information technology"
] |
69,906,594 | https://en.wikipedia.org/wiki/European%20Dialogue%20on%20Internet%20Governance | European Dialogue on Internet Governance (EuroDIG) is a Pan-European multi-stakeholder forum focused on Internet Governance. It is a regional sub-forum of the global Internet Governance Forum (IGF). It is an annual meeting with open participation and changing locations across European countries. Participants come from the private sector, governments, civil society, academia, and the technical community. Notable participating institutions are the European Commission and the Council of Europe.
Mission and history
EuroDIG held its first meeting on 20–21 October 2008 and was initiated by Internet enthusiasts from all stakeholder groups who shared the same vision of a space where all stakeholders from all across Europe could meet and discuss Internet governance issues. The Council of Europe was among the institutions which supported this idea from the beginning and offered to host the first meeting in the Palais de l'Europe in Strasbourg, the headquarters of the Council of Europe.
One goal of EuroDIG is to feed in European views into the global IGF, but even more it aims to reach out to all concerned groups and facilitated an inclusive debate about the governance of the internet by encouraging cooperation to solve problems and find best practices.
Organizational structure and finance
Administration and planning
The central administration of EuroDIG is its secretariat, which is responsible for coordinating the organization. The secretariat is composed of 3-4 individuals working part time as of 2022. Long-term and financial planning as well administrative oversight lies with the Multi-stakeholder Board, whose seven members are elected by the General Assembly, except the Secretary General, who is always part of the board. Members of the Board have to be so-called Core Members and are elected for up to three years. The Members should come from different stakeholder groups so that each group is represented and no group dominates the board. The General Assembly is composed of the members of the organization, though only Core Members can vote. Core Members are Founding and Full Members. All Full Members have to be accepted by the Core Members.
The annual meetings are planned in an open process in which everyone can suggest topics and participate. The program is made based on submitted topics and publicly discussed in a planning meeting, usually at the beginning of the year. The details for each session are assigned an Org Team, which organizes the session. The planning process is facilitated by the secretariat in assisting Org Teams.
Funding and institutional partners
EuroDIG is financed through donations, for the most part by corporations and institutions, but also individuals have an opportunity to support via fundraising tool. Another form of support EuroDIG receives is in the form of hosting the in-person events and providing equipment and resources needed for those, which is usually done by a partnering institution or city.
The institutional partners of EuroDIG are:
Council of Europe
European Commission
European Regional At-Large Organization (EURALO)
European Broadcasting Union (EBU)
European Telecommunications Network Operators’ Association (ETNO)
Geneva Internet Platform
Internet Corporation for Assigned Names and Numbers (ICANN)
Internet Society (ISOC)
Federal Office of Communications of Switzerland (OFCOM)
Réseaux IP Européens Network Coordination Centre (RIPE NCC)
Besides the above mentioned Institutional Partners donations are received from e.g. EURid, Google, SIDN, nic.at, denic, Centr, .fr, SWITCH, VERISIGN, UNINETT Norid, as well as the Internet Society Foundation, UNU-CRIS, RNIDS and, in a smaller amount, regional companies and private donors.
Participants
In 2021, the forum counted 703 registrations for the 3-day long virtual meeting, of which 470 actually attended the event. In addition, more people took part via live stream. For more than 50% of the participants, it was the first EuroDIG they attended. Moreover, 10% of the participants were members or representatives of governments, whereas nearly a fourth of the 470 people attended from civil society. Less than 20% of the attendants identified as academics. Also, nearly 13% of the participants came from the private sector and the technical community, each. Round about 6% of the participants represented inter-governmental organizations. In 2021, special greeting words were held by Patrick Penninckx (Head of Information Society Department, Council of Europe), Ana Persic (UNESCO), Atish Dabholkar (Director, International Centre for Theoretical Physics), Roberto Viola (Director General for Communications Networks, Content and Technology, European Commission), Tatjana Matić (Minister of Trade, Tourism and Telecommunications, Republic of Serbia), Philippe de Lombaerde (Director Ad Interim of the United Nations University Institute on Comparative Regional Integration Studies) and Delphine Ernotte (Director General France Télévisions and President of EBU). While there was a small overlap of male participants in 2021 (50,6%), nearly 45% of the attendants were females (44,1%). The remaining 5,3% of the participants did not want to state their gender.
List of meetings
Source for the table information
Activities of EuroDIG
YouthDIG
Each year, EuroDIG holds a preparatory youth event for interested individuals in the age between 18–30. In this YouthDIG the participants are taught about Internet Governance and develop policy messages which are presented at the following EuroDIG and during the IGF.
Those young people are invited to exchange as well as discuss ideas with experienced Internet policy practitioners. Also, they get the opportunity to connect with peers throughout Europe who have similar interests.
Relationship to other Internet Governance Institutions
EuroDIG was established, with support from the Council of Europe, Swiss OFCOM and other stakeholders, following the commissioning of the Internet Governance Forum (IGF) by the Secretary General of the United Nations in 2006. Its debates and messages are fed into the global forum. Similar to the IGF, EuroDIG has no executive capacity and exists only as a place for discussion.
However, EuroDIG has access to important decision makers in internet policy in Europe, including the Council of Europe, the European Commission (through DG-Connect), ICANN, and members of the European Parliament. By organising EuroDIG in another European country every year the forum built relations with local authorities and governments across Europe as well as various European-wide bodies dealing with internet government issues.
Moreover, EuroDIG supported the creation of SEEDIG ("South Easters European Dialogue on Internet Governance") which is a sub-regional IGF founded in 2015. EuroDIG offered to host the first meeting as a pre-event to EuroDIG in Sofia so that SEEDIG could build relationships between their community and key partners across Europe.
See also
Internet Governance Forum (IGF)
African Internet Governance Forum (AfIGF)
South Eastern European Dialogue on Internet Governance (SEEDIG)
References
External links
Official website
Organizations established in 2008
Internet governance organizations
Information and communication technologies for development | European Dialogue on Internet Governance | [
"Technology"
] | 1,394 | [
"Information and communications technology",
"Information and communication technologies for development"
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69,907,414 | https://en.wikipedia.org/wiki/African%20Internet%20Governance%20Forum | The African Internet Governance Forum (AfIGF) is a multistakeholder forum that facilitates dialogue on Internet governance issues. It is one of the 19 regional IGF initiatives and aims to address and discuss the issues of all 54 nations in Africa.
Mission and history
The African Internet Governance Forum was established during the global IGF held in Nairobi in 2011. 2nd to 4 September, the Council of Ministers of ICT of the African Union approved of the institution.
The first AfIGF meeting, where participants determined its terms of reference, took place in Cairo in 2012. Since then, eight other meetings have followed.
Organisational structure and finance
Secretariat
AfIGF’s secretariat is structured in a similar way to the global IGF’s secretariat. Its host is the United Nations Economic Commission for Africa (UNECA) and it also receives support from the African Union Commission. It is located in Addis Abbaba.
The secretariat’s duties include administrative, logistical and organizational tasks, promotion of the members’ AfIGF activities and maintaining AfIGF and itself. It gathers the knowledge and resources about AfIGF and manages sub-regional and national IGFs in Africa while overviewing the different sub-regional and national IGF’s needs. Moreover, the secretariat summons AfIGF meetings and provide up-to-date information about AfIGF to the public.
Bureau
The Bureau of the African Internet Governance Forum consists of the five regional IGF conveners or their designates. The host country of the last AfIGF chairs the bureau.
Funds
The AfIGF’s meetings are financed by the host country. The forum also receives funds from different organizations, such as PRIDA, UNDESA, ICANN and AFRINIC.
Participants and participation
Participants come from all African member states and Africa's subregional IGFs (WAIGF, EAIGF, SAIGF, FGIAC and NAIGF). In addition, academia, the private sector, the civil society, and regional and international organizations are also involved.
Registration to participate in an AfIGF meeting is possible online.
AfIGF meetings
The African Internet Governance Forum hosts fora annually. It also represents the African continent at global IGFs and holds workshops there. Every year, the AfIGF is hosted by another country:
AfIGF 2012, Cairo, Egypt: The first meeting of the AfIGF was hosted by the government of Egypt and held in Cairo from 2 to 4 October 2012. Three workshops were held prior to the conference. The first workshop was organized by ECA, the second was held by Google, APC and NPCA and the third by OIF. There were also reports from the five sub-regional IGFs and from several countries. The conference was rounded off with various presentations, e.g. on access and diversity, security, openness and privacy as well as the African digital representation strategy, and several recommendations were made.
AfIGF 2013, Nairobi, Kenya: The second AfIGF took place in Nairobi in Kenya from the 11th to the 13th of September, 2013 and was organized by the Government of Kenya, the AUC, UNEVCA and TESPOK. The main theme for the second meeting was "Building Bridges – Enhancing Multi-stakeholder Cooperation for Growth and Sustainable Development". Conference topics included multi-stakeholder cooperation, infrastructure development, security, openness, and access and security. The three pre-conference workshops addressed multi-stakeholder-participation in ICT policy processes in Africa, Cyber security in Africa and data protection in Francophone African countries. Several recommendations were formulated.
AfIGF 2014, Abuja, Nigeria: The third meeting of the AfIGF took place in Abuja, Nigeria, from the 10th to the 12th of July, 2014. The overall theme of the meeting was “Connecting Africa for enhanced multistakeholder Internet governance”. Organizers of the conferences were the Federal Ministry of Communications and Information Technology and the ECA, supported by other institutions. Again, there were workshops, reports and panel discussions before the forum.
AfIGF 2015, Addis Ababa, Ethiopia: The fourth AfIGF meeting was held in Addis Ababa, Ethiopia from 6 to 8 September 2015, after the Ministerial Conference on Communication and ICT. The AUC and UNECA organized the forum in cooperation with the NEPAD Agency and were supported by different entities. The objectives of the forum included discussing Africa’s common position on internet governance. Four different pre-conference workshops were held: “African Virtual Library and Information Network (AVLIN)”, “WSIS Follow up”, “UNESCO Internet Study” and “Internet and Human Rights and Capacity building needs for IG and Internet public policy dialogues”. The discussions lead to some conclusions and recommendations.
AfIGF 2016, eThekwini, Kwazulu Natal, Durban: The fifth meeting of the AfIGF was held in eThekwini, Kwazulu Natal, Durban from the 16th to the 18th of October 2016. Several presentations were presented during the main conference, covering topics such as internet innovation, security and privacy, the role of libraries, gender divide in the digital transformation and the role of internet governance concerning development goals. The meeting was streamed live with over 1200 spectators.
AfIGF 2017, Sharm El Sheikh, Egypt: The 6th AfIGF meeting took place in Sharm El-Sheikh in Egypt from the 4th to 6 December 2017 under the slogan “Enabling an Inclusive Digital Transformation of Africa”. The conference was organized by the AUC in cooperation with the National Telecom Regulatory Authority of Egypt and the NEPAD Coordination Agency. The sessions covered different topics, e.g. DNS and policy making, digital transformation, internet freedom and cybersecurity. Right before the AfIGF meeting, the African School on Internet Governance was held from November 28 to December 2, and the North Africa IGF (NAIGF) took place from 2nd to 3 December 2017.
AfIGF 2018, Khartoum, Sudan: In 2018, the seventh AfIGF meeting happened in Khartoum in Sudan from the 4th to 6 November, organized by the AUC in cooperation with the government of Sudan and supported by different entities. The annual motto was “Development of the Digital Economy and Emerging Technologies in Africa”. Parallel sessions addressed various topics, e. g. achieving more (non-discriminatory) internet access and legal issues like human rights and protection of children and youth. Other sessions included talks about “Internet shutdowns”, “African court for online conflict resolution” and “Cybersecurity for the use and harnessing of ICT”. In addition, there was a consultation meeting, an inducting session, several plenary sessions, hosted by various people.
AfIGF 2020, virtual: Due to the COVID-19 pandemic, the eighth AfIGF was held virtually from the 24th to the 27th of November, 2020. The African Youth Internet Governance Forum took place on November 24 as well. The AfIGF conference consisted of different parallel workshop sessions and plenary sessions about data (e.g. “Key issues in Data protection policy making and implementation”), economy (e.g. “The digital economy in Africa, possibilities and challenges”), inclusion (e.g. “Safe, stable and reliable internet: digital rights of citizens”), policies (e.g. “Policy Consideration for Community Networks in Africa”), youth (e.g. “E-commerce: What challenges and opportunities for entrepreneurial youth”) and more.
AfIGF 2021, virtual: The tenth meeting of the AfIGF also took place virtually from the 14th to the 16th of December 2021 with the motto “Advancing digital transformation in Africa in the face of Crisis”. The conference was organized by the government of Nigeria and supported by different partners. It consisted of parallel workshops and plenary sessions. Some workshops also addressed the pandemic, e.g. the session “Covid 19, Digital Rights and Impacts on Communities in Africa” by IGF Camaeroon or the session “Barriers and opportunities: The state of Internet access and affordability in African countries during the COVID-19 pandemic”.
African School on Internet Governance
In addition to the African Internet Governance Forum, there is the African School on Internet Governance (AfriSIG), which is co-convened by the Association for Progressive Communications, the Information Society Division of the African Union Commission (AUC) and Research ICT Africa. Its objective is promoting collaboration among various stakeholders in national to global internet policy and development. First held in Durban (South Africa) in 2013 (with 13 participants from 12 countries), the ninth annually course took place virtually from the 4th to the 15th of October 2021, addressing digitalization, internet governance and architecture, social issues like human rights and gender in the context of internet governance, cybersecurity and content-regulation. The participants were experienced in the field of internet governance or information technology and members of designated stakeholder groups.
Relationship to other internet governance institutions
As one of the 19 regional IGF initiatives, the AfIGF is connected to the global IGF. Its role is to bring in topics from the African continent to the global IGF and it is committed to ensure that all Africans benefit from a viable information society. The forum also ensures a multistakeholder representation from Africa at the global IGF and promotes exchange between different stakeholders and countries.
There are also five sub-regional Internet Governance initiatives: West Africa Internet Governance Forum (WAIGF), East Africa Internet Governance Forum (EAIGF), North Africa Internet Governance Forum (NAIGF), Southern Africa Internet Governance Forum (SAIGF) and the Forum de Gouvernance de lÌnternet en Afrique Centrale (FGI-CA).
See also
Internet Governance Forum (IGF)
United Nations Department of Economic and Social Affairs (UNDESA)
United Nations Economic Commission for Africa (UNECA)
EuroDIG
References
Internet governance organizations
Information and communication technologies for development
Internet in Africa
2011 establishments in Africa
Organizations established in 2011
Information technology organizations based in Africa | African Internet Governance Forum | [
"Technology"
] | 2,041 | [
"Information and communications technology",
"Information and communication technologies for development"
] |
69,907,759 | https://en.wikipedia.org/wiki/Racial%20diversity%20and%20discrimination%20in%20STEM%20fields | According to the National Science Foundation (NSF), women and racial minorities are underrepresented in science, technology, engineering, and mathematics (STEM). Scholars, governments, and scientific organizations from around the world have noted a variety of explanations contributing to this lack of racial diversity, including higher levels of discrimination, implicit bias, microaggressions, chilly climate, lack of role models and mentors, and less academic preparation.
Race imbalance in STEM in the United States
Racial minorities, with the exception of Asian Americans, are underrepresented through every stage of the STEM pipeline.
Education and degree attainment
Racial disparities in high school completion are a prominent reason for racial imbalances in STEM fields. While only 1.8% of Asian and 4.1% of White students drop out of high school, 5.6% of Black, 7.7% of Hispanic, 8.0% of Pacific Islander, and 9.6% of American Indian/Alaskan Native students drop out of high school. Among those that graduate high school, 67% of Whites, 62% of Blacks, and 69% of Hispanics enroll in a “degree granting college.” While there is no measurable difference in college enrollment of White, Black, and Hispanic STEM students, only 15% of Black students who initially enrolled in a STEM major received a STEM bachelor's degree at graduation, compared to 30% of White and Asian students.
Employment, occupation, and income
According to the National Science Board, which provides statistical data on the U.S. labor force, Asians represent 9%, Whites 65%, Hispanics 14%, and Blacks 9% of the STEM labor force. In particular, white men are 49% of the STEM labor force. Among different STEM fields, Blacks make up only 4% of life science, 5% of engineering, 6% of physical sciences, 7% of the computer science, 9% of math and 11% of health-related sciences. There are also significant wage gaps between women, men, and people of color, especially in STEM jobs. An example of this disadvantage is the gender pay gap and racial pay gap in computer science fields, where women earn about 74% of what men earn and the median income for White workers is approximately 23.3% more than the median income for Blacks. The gender and racial pay gaps in STEM fields are significantly greater than all regular non-STEM jobs with an even greater pay gap between these gender, racial, and ethnic groups. When first being hired, 35% of women of color reported negotiating their salaries, but nearly 50% wished that they had negotiated their salary after starting the job. Many of these women reported being initially satisfied with the salary they had been offered when being hired, but later learned that they were earning much less than other workers at their same level.
Effects of underrepresentation of people of color in STEM
Among Black workers in STEM fields, 57% feel that there too little attention being directed toward adding more racial and ethnic diversity in the workplace. This lack of diversity contributes to isolation and a lack of social support in the workplace which can increase anxiety and depression for many people of color in STEM.
Explanations for the underrepresentation for people of color
Recently, scholars have begun applying the framework of systemic racism to explain the experiences of racial minorities in STEM. Specifically, research indicates that people of color, especially blacks, experience higher levels of discrimination, incur various microaggressions, and a lack of overall mentorship and support in STEM.
Stereotypes and preconceived notions of STEM
Scientific racism of the late 19th and early 20th centuries attempted to identify biological, intellectual, and physiological differences among races. Lasting effects of the scientific racism include racial stereotypes about students of color and preconceived notions of STEM as predominantly a white, male field. A study highlighting the underrepresentation of women and racial minorities in STEM found that Asian and White candidates were viewed as more competent and hirable than Black and Latino/a candidates. Similarly, survey results from this study show that students were much more likely to recognize and name white male STEM professionals than Black or women STEM professionals. Additionally, students of color on college campus often face prevailing societal misconceptions and assumptions that they are affirmative action beneficiaries, on sport scholarships, and/or “at-risk” students. Students of color additionally must contend with stereotype threat that has been found to lower academic achievement. In particular, high-achieving Black students, attempting to combat prevailing stereotypes about their lack of intelligence, while Asian students combat the prevailing model minority stereotype presuming they are biologically predisposed to mathematical ability.
Stem identity
The development of a STEM identity increases the overall likelihood that a student will continue to develop scientific literacy and pursue a STEM career. The National Research Council's 2009 report describes students developing STEM identities as learning to “think about themselves as science learners and develop[ing] an identity as someone who knows about, uses and sometime[s] contributes to science.” Black girls are less likely to develop STEM identities in middle school because they have fewer science-related experiences outside of school and less confidence in their scientific ability than Asian-American, Latina, and White middle school girls, making them less likely to enter STEM fields in the future. Additionally, research demonstrates that beyond first-hand experience with science, societal norms, stereotypes, and interactions with peers, teachers, and family contribute to the development of a STEM identity.
Microaggressions
People of color and underrepresented minority groups in science, technology, engineering and math are more likely than whites to experience racial microaggressions. Studies show racial microaggressions that occur on college campus weaken students sense of belonging, make it difficult to form relationships with faculty, and contribute to less cultural alignment with STEM. At predominantly white institutions (PWI) environmental microaggressions are common in shared laboratory spaces among students and during meetings with faculty and advisors. Black female students are especially likely to feel alienated and isolated from their peers in STEM departments.
Implicit bias
Research on implicit bias demonstrates that as early as preschool teachers are likely to hold implicit bias against students of color, especially Black boys. While Black children make up 19% of preschool enrollment, they account for about half of preschool suspension. Implicit biases among teachers, faculty, and colleagues makes it more difficult for students of color to form relationships, network with professionals in their fields, and find valuable mentors. Judgements placed upon people of color based on implicit biases are incredibly damaging and contribute to stereotype threat, which affects their overall performances. For instance, Black women are often assumed to be underqualified forcing them to prove that they deserve to be in those spaces as was the case of Katherine Johnson depicted in Disney's "Hidden Figures".
Sense of belonging
When people do not feel welcome in a place, environment, or institution, they are less likely to feel they belong and more likely to withdraw. In particular, women and people of color often adopt individual strategies of assimilation or patriarchal bargaining in their attempt to gain acceptance. For example, Black male scientists adopt coping strategies to endure racialized interactions with colleagues and managers. Similarly, Black female undergraduates students describe coping with racism on campus by gravitating toward same-race peers, faculty, and staff. When underrepresented groups are forced to adapt or leave the field altogether, it costs STEM valuable talent and perspectives that could be used to advance scientific discoveries and advancements.
STEM pipeline
The STEM pipeline starts to narrow early as students of color face additional barriers to STEM participation in school. The following are some examples of these barriers.
Primary and secondary schools
Research indicates that racial disparities in science achievement test scores begin as early as third grade. These test score disparities were attributed to both socioeconomic status gaps between races and school qualities. In particular, Black and Hispanic students are more than double as likely to live in low-income neighborhoods compared to White students which directly contributes to less money for local public schools and indirectly less funding for STEM programs. Black and Latino/a may not always have the same access to higher level high school courses that are building blocks for success in College STEM fields. For example, those who have not taken high school trigonometry, calculus, or physics, are put at a disadvantage in terms of graduating with a STEM degree. Beyond academic preparation, experiences with STEM across various settings, including school, home, and out-of-school, help students of color see STEM careers as more possible.
College
While Black males are twice as likely as their white peers to declare a STEM major upon entering college, they are less likely to graduate with a STEM degree. Scholars point to microaggressions, a chilly climate, and lack of role models and mentors as contributing to students of color being "weeded out” of STEM majors. Additionally, one study examining Black male engineering graduate students found that microaggressions from counselors, mentors, and fellow students resulted non-normative role strain. These actors increase the likelihood that people of color leave STEM majors.
Mentorship
Because white men are still overrepresented in STEM fields there is a lack of available mentorship from faculty and scientists of color. As a result, students of color in STEM feel unheard, excluded, and lose opportunities to make connections with peers. Research does indicate that students of color at HBCU's are much more likely to perceive their mentors to be supportive and describe more positive interactions with peers.
Work
Underrepresented minorities, including women, people of color, and LGBT individuals are more vulnerable to experience discrimination, isolation, and/or harassment in their workplaces. A Pew survey of men and women in STEM indicates that 50% of women in STEM experienced gender-related discrimination at work and about 62% of Black people in STEM jobs stated they experienced racial discrimination at work. Additionally, 72% of Black STEM workers believe that facing racial discrimination is a major reason why there are not more people of color in STEM fields.
Strategies for increasing participation of people of color in STEM
Underrepresentation of people of color in STEM is a problem that is rooted to white supremacy and racism.
Bias training
Many scholars and organization recommend elimination of bias as a means to increase representation in STEM. Specifically, implicit bias, training of students, managers, faculty, and even students is seen as one way to combat stereotypes and reduce microaggressions targeting people of color. Additionally, incorporating implicit bias statements and policies can strengthen a commitment to diversity and inclusion within institutions.
Protective factors
Those in STEM fields have recognized that there is an extensive history of poor representation of women and people of color in STEM and are working to close the gap. Addressing this issue requires a coherent and sustained effort across multiple fronts. Many would argue that single intervention does not work, but that sustainable and strategic reform in education, work place, and within our communities would put our theory in to practice. Transforming our perception of STEM in the early education years for students of color necessitates celebration of the distinct contribution that women and people of color bring to science, technology, engineering, and mathematics.
Teachers
While many teachers are highly dedicated to reducing the race gap and actively striving to create equal opportunities in their classrooms, they can actually contribute to the STEM race gap. It is important that teachers understand that their actions impact students’ futures more than they may realize.
Role models
One of the most promoted solutions is the need for role models. While both female and male role models can be effective in recruiting women in STEM fields there is a lack of role models of color to mentor POC in STEM fields. When individuals have someone to look up to that looks like them, they are more willing to stay in the field and develop a sense of belonging. Opportunities to engage and connect with individuals in STEM allows for excitement to be a part of this community and the development of a stronger STEM identity.
Mentors
Mentors provide students the academic and social support they need to succeed in STEM, however, having same-race mentorship is an important step in retaining students of color in STEM. Not only do students of color report more positive interactions with same-race faculty, they are also more likely to develop stronger STEM identities.
Organized efforts
There is a growing number of organizations whose goal is to increase diversity in STEM fields by encouraging girls and women to thrive in STEM environments. An example of one of these organizations is Girls Who Code. Their mission is to successfully close the gender gap in new entry-level tech jobs by 2030. Girls Who Code focuses their work not only on gender diversity but also on young women who are historically underrepresented in computer science fields, including African American/Black, Hispanic or Latina, Bi/ Multiracial, Native American/Alaskan, and Native Hawaiian/Pacific Islander, those who come from low-income backgrounds, specifically free and/or reduced lunch eligible, and those who have had a lack of exposure or access to computer science. Girls Who Code acknowledges and values the intersections of race/ethnicity, gender identity and expression, class, sexual orientation, ability, age, national origin, and religious/spiritual identities.
Similarly, Black girls who participated in I AM STEM, a community nonprofit organization designed to increase STEM participation among underrepresented groups, engaged directly in first-hand scientific research which contributed to stronger connections to STEM.
Another great example of organizations for the underrepresented is the Society for advancement of Chicanos/Hispanics and Native Americans in Science (SACNAS). SACNAS's mission is to advance the success of Chicanos/Hispanics and Native Americans in securing advanced degrees, careers, and positions of leadership in STEM fields. The organization has been working to make sure that those most underrepresented in STEM have the support they need to attain advanced degrees, careers, and positions of leadership. SACNAS also often points out that diverse voices bring creative solutions to our world's most pressing scientific problems and that building a national network that is innovative, powerful, and inclusive is necessary.
Important scientists, engineers, and mathematicians
Katherine Johnson
West Area Computers
Dorothy Vaughan
Mary Jackson
Raychelle Burks
Jedidiah Isler
Ellen Ochoa
Ruby Hirose
Rebecca Lee Crumpler
France A. Cordova
Claudia Alexander
Susan La Flesche Picotte
Alice Ball
Janaki Ammal
Linda Garcia Cubero
Hedy Lamarr
Nadine Caron
Neil deGrasse Tyson
John Herrington
Mary G. Ross
Luis Walter Alvarez
Ella Cara Deloria
Witri Wahyu Lestari
Aaron Yazzie
Nanibaa' Garrison
See also
Racial discrimination
Imposter syndrome
Racial Diversity in United States Schools
Internalized Racism
Institutional Racism
White Privilege
Racial Wage gap
Society for the Advancement of Chicanos/Hispanics and Native Americans in Science
National Society of Black Engineers
National Organization for the Professional Advancement of Black Chemists and Chemical Engineers
Stereotype Threat
Microaggressions
Harassment
Gendered Racism
Scientific Racism
Women in STEM
STEM Pipeline
Structural Inequality in Education
Underrepresented Groups in STEM
Implicit Stereotype
Racial equality
Hidden Figures
Marginalization
Affirmative action
References
Engineering education
Science education
Women in science and technology | Racial diversity and discrimination in STEM fields | [
"Technology"
] | 3,094 | [
"Women in science and technology"
] |
69,908,110 | https://en.wikipedia.org/wiki/Elena%20Queirolo | Elena Queirolo is an Uruguayan toxicology researcher and advocate who founded the Health Clinic for Environmental Chemical Contaminants at the Pereira Rossell Hospital (Policlínica de Contaminantes Químicos Ambientales del Pereira Rossell), known as the Lead Clinic or Lead Polyclinic. She is affiliated with the Catholic University of Uruguay.
The clinic was founded in April 2001 in response to the La Teja incident, in which the public became aware of lead and other chemical exposure to children. After the incident, the clinic and Queirolo became data collectors and advocates for establishing lead exposure standards more similar to the guidelines in the US and Canada.
She has been a primary investigator on several major international studies of exposure of children to lead and other chemicals, such as arsenic.
References
Uruguayan medical researchers
Toxicologists
Year of birth missing (living people)
Living people | Elena Queirolo | [
"Environmental_science"
] | 178 | [
"Toxicologists",
"Toxicology"
] |
69,908,834 | https://en.wikipedia.org/wiki/Patrick%20Huber | Patrick Huber is a German theoretical particle physicist known for his calculation of the reactor neutrino flux, and for his work in computing sensitivity of neutrino oscillation experiments and applications of reactor neutrino detection. He is a Professor of Physics Virginia Tech and Director of Virginia Tech's Center for Neutrino Physics. In 2016 he was honored with the Breakthrough Prize in Fundamental Physics for his work on the Daya Bay Reactor Neutrino Experiment.
Education and career
Huber studied at the Technical University Munich, completing his diploma in 2000 and his Doctor rerum naturalium in theoretical Physics in 2003, under the supervision of Manfred Lindner. After completing postdoctoral appointments at the University of Wisconsin–Madison and CERN he started a faculty position in the Virginia Tech Physics Department in 2008, and received tenure in 2012. He became director of the Center for Neutrino Physics in 2017.
Awards and honours
2010 DOE Early Career Researcher Award
2016 Breakthrough Prize in Fundamental Physics
2019 Fellow of the American Physical Society
Select publications
References
External links
| Home page at Virginia Tech
| The Center for Neutrino Physics at Virginia Tech
Living people
Particle physicists
Virginia Tech faculty
21st-century German physicists
German theoretical physicists
Neutrino physicists
Fellows of the American Physical Society
Technical University of Munich alumni
Year of birth missing (living people)
People associated with CERN | Patrick Huber | [
"Physics"
] | 272 | [
"Particle physicists",
"Particle physics"
] |
69,914,127 | https://en.wikipedia.org/wiki/Javad%20Owji | Javad Owji (; born 24 July 1966) is an Iranian oil engineer and politician who served as the Minister of Petroleum of Iran from 2021 to 2024.
Early life and education
Owji was born in Shiraz in 1966. He received a bachelor's degree in oil engineering from Petroleum University of Technology in Ahvaz.
Career
From 1980 Owji worked in the oil-related public offices. He was the deputy oil minister and the head of the National Iranian Gas Company from 2009 to 2013 during the last term of President Mahmoud Ahmadinejad. He also served in various oil-related posts, including chairman of the board of supervision of production and gas refineries and vice chairman of Petro Mofid Oil and Gas Development Holding. Owji was nominated by President Ebrahim Raisi as oil minister on 11 August 2021. On 25 August Owji was confirmed by the Majlis with 198 to 70 with 18 abstentions. He succeeded Bijan Namdar Zangeneh in the post.
References
External links
20th-century Iranian engineers
21st-century Iranian engineers
21st-century Iranian politicians
1966 births
Directors of the National Iranian Oil Company
Living people
Oil ministers of Iran
Politicians from Shiraz
Petroleum University of Technology alumni
Petroleum engineers | Javad Owji | [
"Engineering"
] | 249 | [
"Petroleum engineers",
"Petroleum engineering"
] |
69,914,845 | https://en.wikipedia.org/wiki/List%20of%20species%20named%20after%20the%20COVID-19%20pandemic | A number of species have been named after the COVID-19 pandemic. The names of the new species may refer to the virus itself, to the pandemic, to the lockdowns, or to something more intricate, such as the name of a person dead from the disease.
Animals
(in alphabetical order of genera)
Achilia covidia Kurbatov, Cuccodoro & Sabella, 2021 (Insect, Coleoptera, Staphylinidae) – "the epithet of this new species refers to the COVID-19 pandemic and the periods of quarantine during which this study was carried out by the authors".
Achilia pandemica Kurbatov, Cuccodoro & Sabella, 2021 (Insect, Coleoptera, Staphylinidae) – "the epithet of this new species refers to the COVID-19 pandemic and the periods of quarantine during which this study was carried out by the authors".
Achilia quarantena Kurbatov, Cuccodoro & Sabella, 2021 (Insect, Coleoptera, Staphylinidae) – "the epithet of this new species refers to the COVID-19 pandemic and the periods of quarantine during which this study was carried out by the authors".
Allorhogas quarentenus Joele, Zaldívar-Riverón & Penteado-Dias, 2021 (Insect, Hymenoptera, Braconidae) – "The name of this species refers to the COVID-19 pandemics with its subsequent undefined quarantine, which occurred while the authors were describing it".
Carinadelius medicus Ranjith, van Achterbergan Achterberg, Samartsev & Nasser, 2021 (Insect, Hymenoptera, Braconidae) – "Named after Friedrich Kasimir Medikus (1738 – 1808), a German physician and botanist. We dedicate this species with gratitude to all doctors and nurses for their timeless and uncompromising efforts to control COVID-19".
Cephalothrips corona Alavi & Minaei, 2021 (Insect, Thysanoptera, Phlaeothripidae) – "This article was prepared during the first author's quarantine period due to his positive test for the Coronavirus diseases".
Coralliozetus clausus Hastings, 2021 (Fish, Perciformes, Chaenopsidae) – " from the Latin meaning 'enclosed' or 'having been shut off,' in reference to the restricted distribution of this species, known only from Isla del Coco, Costa Rica. The name also refers to the isolation imposed on the author by the COVID-19 pandemic, providing an opportunity to complete the description of this species whose distinctiveness had been known for some time. The common name of "Pandemic Blenny" ("" in Spanish) is suggested in light of these difficult times".
Corethrella menini Feijó, Picelli, Ríos-Velásquez & Pessoa, 2021 (Insect, Diptera, Corethrellidae) – "Corethrella menini sp. nov. is named in honor of Dr. Marcelo Menin as a tribute to his important work as a herpetologist, focused on ecology and biology of anurans. Marcelo was a professor of zoology who inspired dozens of zoology students, a beloved friend. He passed away too young during the COVID pandemic."
Epeus covid Lin, Y.J., Li, S.Q. & Pham, D.S. 2023. Taxonomic notes on some spider species (Arachnida: Araneae) from China and Vietnam.
Gigantometopus coronobtectus Kim, Taszakowski & Jung, 2021 (Insect, Hemiptera, Miridae) – "Coronobtectus from the name "coronavirus" and the Latin word , meaning covered, because the dark band on its frons resembles dark protective masks worn by people during the pandemic of COVID-19."
Humbertium covidum Justine, Gastineau, Gros, Gey, Ruzzier, Charles & Winsor, 2022 (Flatworm, Tricladida, Geoplanidae) – "the specific name covidum was chosen as homage to the numerous casualties worldwide of the COVID-19 pandemic. Furthermore, a large part of this study was written during the lockdowns"
Nisitrus rindu Robillard & Tan, 2021 (Insect, Orthoptera, Gryllidae) – "This species name refers to the word '', which means 'love' [verb] in Iban [a group of indigenous people from Borneo] language and 'home-sickness' = 'miss' [verb] in Bahasa Melayu (Malay language) and Indonesian. This new species is dedicated to the front-liners fighting against the COVID-19 pandemic who were far from their homes and loved ones during the early phase of the global pandemic (when the speciesʼ name was chosen)".
Oxymorus johnprinei Borovec & Meregalli, 2020 (Insect, Coleoptera, Curculionidae) – named "in memory of the late John Prine (1946–2020), American folk singer and songwriter who sadly passed away due to COVID-19 while the authors were completing the paper"
Parmulopsyllus iamarinoi Borges, Farias, Mácola, Neves & Johnsson, 2021 (Crustacean, Siphonostomatoida, Entomolepididae) – "named in honor of Atila Iamarino, biologist, PhD in microbiology and scientific communicator for his notorious work informing, educating and raising awareness in combating misinformation about covid- 19".
Potamophylax coronavirus Ibrahimi, 2021 (Insect, Trichoptera, Limnephilidae) – named after the coronavirus
Periclimenaeus karantina Park & De Grave, 2021 (Crustacean, Decapoda, Palaemonidae) – named from the Greek (, 'quarantine'), referring to the lifestyle of the new species within the host ascidian species. It also alludes to the quarantine of human society due to the coronavirus pandemic (COVID-19), during which time this paper was written.
Segestes nostosalgos Tan & Wahab, 2020 (Insect, Orthoptera, Tettigoniidae) – named after 'homecoming' (, 'homecoming' in Greek) and 'pain' (, 'pain, grief or distress' in Greek). The authors wrote that "the species is dedicated to those who are far away from home during the Covid-19 pandemic and any difficult times".
Sibogasyrinx clausura Kantor & Puillandre, 2021 (Mollusc, Conoidea, Cochlespiridae) – named (noun in apposition), meaning 'lockdown', "with reference to the sanitary restrictions associated with SARS-COV-2 that prevailed over much of the World when this manuscript was finalized".
Stethantyx covida Khalaim & Ruíz-Cancino, 2020 (Insect, Hymenoptera, Ichneumonidae) – "named after the Covid-19 (Coronavirus) because the taxon was described while the outbreak of this virus in Mexico."
Thoonchus covidus Zograf, Pyvlyuk, Trebukhova & Li, 2020 (Nematode, Enchelidiidae) named after the disease
Trigonopterus corona Narakusumo & Riedel, 2021 (Insect, Coleoptera, Curculionidae) – named after the coronavirus
Typhlamphiascus medici Gómez, Corgosinho & Rivera-Sánchez, 2021 (Crustacean, Harpacticoida, Miraciidae) – "The specific epithet from the Latin '', 'doctor', 'physician', is dedicated in honour and to the memory of all physicians and health personnel for their self-sacrifice during the fight against the COVID-19 pandemic."
Fungi
(in alphabetical order of genera)
Dendrostoma covidicola Samarak. & Jian K. Liu, 2021 (Diaporthales, Erythrogloeaceae) — the epithet covidicola referring to "the COVID-19 pandemic and as a tribute to the battle against COVID-19."
Diabolocovidia claustri – name of genus (Diabolocovidia) based on the virus and name of species (claustri) based on the lockdown
Laboulbenia quarantenae De Kesel & Haelew., 2020 (Laboulbeniales, Laboulbeniaceae) – named after the quarantine.
Plants
(in alphabetical order of genera)
Hypnea corona Huisman & Petrocelli, 2021 (Algae, Gigartinales, Cystocloniaceae) – the authors wrote: "The epithet is from the Latin (a crown) and refers to crown-like appearance of the propagules. This epithet was selected prior to the 2020/2021 pandemic, but its use can also serve as a reminder of this difficult period".
References
External links
Lists of eponyms
COVID-19 pandemic
Biological nomenclature
Botanical nomenclature
Impact of the COVID-19 pandemic on science and technology
Zoological nomenclature | List of species named after the COVID-19 pandemic | [
"Technology",
"Biology"
] | 2,021 | [
"Zoological nomenclature",
"Botanical nomenclature",
"Botanical terminology",
"Biological nomenclature",
"Impact of the COVID-19 pandemic on science and technology",
"History of science and technology"
] |
71,466,306 | https://en.wikipedia.org/wiki/42%20Leonis%20Minoris | 42 Leonis Minoris (42 LMi) is a solitary, bluish-white hued star located in the northern constellation Leo Minor. It has a visual apparent magnitude of 5.35, allowing it to be faintly seen with the naked eye. Parallax measurements place it at a distance of 412 light years. The object has a heliocentric radial velocity of , indicating that it is drifting away from the Solar System.
42 LMi has a general stellar classification of B9 V, indicating that it is an ordinary B-type main-sequence star. However, Cowley et al. (1969) gave a slightly cooler class of A1 Vn, indicating that it is instead an A-type main-sequence star with 'nebulous' (broad) absorption lines due to rapid rotation. Nevertheless, it has 2.77 times the mass of the Sun and a radius of . It radiates at 107 times the luminosity of the Sun from its photosphere at an effective temperature of . Its high luminosity and slightly enlarged diameter suggests that the object might be evolved. Like most hot stars, 42 LMi spins rapidly with a projected rotational velocity of .
There are two optical companions located near this star. BD+31°2181 is a 7th magnitude K2 giant star separated away along a position angle of . An 8th magnitude companion has been detected at a distance of over along a position angle of . Both have no relation to 42 LMi and is just moving with it by coincidence.
An X-ray emission with a luminosity of has been detected around the object. A-type stars are not expected to emmit X-rays, so it must be coming from an unseen companion.
References
B-type main-sequence stars
Leo Minor
Leonis Minoris, 42
093152
52638
4203
BD+31 02180 | 42 Leonis Minoris | [
"Astronomy"
] | 384 | [
"Leo Minor",
"Constellations"
] |
71,466,674 | https://en.wikipedia.org/wiki/Hydrogen%20transport | Hydrogen transport involves the use of technology to transport hydrogen from the point of generation to the point of use.
Techniques
Hydrogen can be transported in a variety of forms.
Gas
Hydrogen can be transported in gaseous form, typically in a pipeline. Because hydrogen gas is highly reactive, the pipeline or other container must be able to resist interacting with the gas. Hydrogen's low density at atmospheric pressure means that gas transport is suitable only for low volume requirements.
Liquid
Hydrogen switches to the liquid phase at . Thus, transporting liquid hydrogen requires sophisticated refrigeration technologies such as cryogenic tanker trucks and liquefaction plants.
Compound
Hydrogen can be reacted with other elements to form a variety of compounds. This allows it to be transported in either liquid (e.g., water) or solid form. One variation on this concept is to transport atomic silicon, produced using renewable energy. Mixing silicon with water separates water's oxygen from its hydrogen without requiring additional energy. The hydrogen can then be oxidixed with the oxygen (or air) to produce energy (with water as the only byproduct).
Mechanochemical
Mechanochemistry refers to chemical reactions triggered by mechanical forces as opposed to heat, light, or electric potential. Ball milling can crush material such as boron nitride or graphene, allowing hydrogen gas to be absorbed by the powder, storing the hydrogen. The hydrogen can be released by heating the powder. These techniques offer the potential of substantial net energy savings.
Safety
Hydrogen transport must address various safety threats.
It is highly flammable, requiring little energy to ignite. However, it is low density (0.0837 g/L), which allows leaked gas to rapidly dissipate, rather than accumulate as a higher density gas might, such as chlorine (3.214 g/L).
Liquid hydrogen requires such low temperatures that leaks may solidify other air components such as nitrogen and oxygen. Solid oxygen can mix with liquid hydrogen, forming a mixture that could self-ignite. A jet fire can also ignite.
At high concentrations, hydrogen gas is an asphyxiant, but is not otherwise toxic.
ISO Technical Committee 197 is developing standards governing hydrogen applications. Standards are available onboard systems, fuel tanks and vehicle refueling systems and for production (including electrolysis and steam methane reformers).
Individual jurisdictions such as Italy have developed additional standards.
See also
Hydrogen transportation
References
External links
Hazardous materials
Energy in transport | Hydrogen transport | [
"Physics",
"Chemistry",
"Technology"
] | 501 | [
"Physical systems",
"Transport",
"Materials",
"Energy in transport",
"Hazardous materials",
"Matter"
] |
71,466,819 | https://en.wikipedia.org/wiki/Octamethylenediamine | Octamethylenediamine (OMDA) is an organic chemical compound from the substance group of aliphatic diamines. It is used as a versatile reaction intermediate in the manufacture of pesticides, especially fungicides.
Manufacture
The industrial production of octamethylene diamine is carried out by the catalytic hydrogenation of suberonitrile at temperatures of 150 to 180 °C and a pressure of 50 to 180 bar in the presence of ammonia over heterogeneous cobalt unsupported catalysts:
The reaction is carried out in the liquid phase and is carried out continuously or batchwise. The catalyst is arranged as a fixed bed in a shaft, tube, or tube bundle reactor.
Characteristics
Octamethylenediamine is a combustible but difficult to ignite. It is a solid that is easily soluble in water. The aqueous solutions are strongly alkaline (pH value of 12.1 at a concentration of 10 g/L).
Use
Octamethylenediamine is used as a versatile intermediate in manufacturing pesticides, especially fungicides.
Safety instructions
While octamethylenediamine is combustible, it is difficult to ignite because it is solid at moderate temperatures. It has a lower explosive limit (LEL) of 1.1 % by volume and an upper explosive limit (UEL) of 6.8 % by volume. The ignition temperature is 280 °C The substance therefore falls into temperature class T3. With a flash point of 113 °C, the liquid is considered difficult to ignite.
References
External links
Corrosive substances
Diamines | Octamethylenediamine | [
"Chemistry",
"Technology"
] | 328 | [
"Corrosive substances",
"Corrosion"
] |
71,468,958 | https://en.wikipedia.org/wiki/Tube%20house | Tube houses (Vietnamese: nhà ống) are a vernacular architectural form of shophouse endemic to Vietnam, characterized by their narrow width and multistory structure. Common throughout the country, tube houses have proliferated as a result of limited building space and property taxation policies assessing only the first floor width of homes. In Hanoi, tube houses originated at the end of the 19th century.
See also
Row house
Shophouse
References
Architectural design
Buildings and structures in Asia
House types
Urban studies and planning terminology
Vernacular architecture | Tube house | [
"Engineering"
] | 103 | [
"Design",
"Architectural design",
"Architecture"
] |
71,469,504 | https://en.wikipedia.org/wiki/Okroy%20Cloud | The Okroy Cloud, is an intergalactic dust cloud near the Milky Way. Its intergalactic nature was first studied by Bogdan Wszolek and Solvia Massi in 1988.
See also
Local Group
Satellite galaxies of the Milky Way
References
Milky Way
Milky Way Subgroup
Virgo (constellation)
Stellar streams
?
Local Group | Okroy Cloud | [
"Astronomy"
] | 68 | [
"Virgo (constellation)",
"Galaxy stubs",
"Astronomy stubs",
"Constellations"
] |
71,470,090 | https://en.wikipedia.org/wiki/Gracilariaceae | The Gracilariaceae is a small family of red algae, containing several genera of agarophytes.
It has a cosmopolitan distribution, in which 24 species are found in China, six in Great Britain and Ireland, and some in Australia and Chile.
They are normally found in intertidal bays, backwaters, and estuaries.
The family have been extensively investigated over the last 30 years, and various studies have yielded comprehensive information on their life history, cultivation, taxonomy, and utilization (Bellorin et al. 2002, Rueness 2005). Studies on the structure of their reproductive organs and the phylogenetic relationships among species inferred from rbcL sequence analyses have produced three clades at the genus level, namely Gracilaria, Gracilariopsis, and Hydropuntia (Gurgel and Fredericq 2004).
In 2012, the University of São Paulo, Brazil set up the Gracilariaceae Germplasm Bank, to use molecule markers for the identification of species.
Genera
As accepted by GBIF;
Crassiphycus (7)
Curdiea (3)
Graacilaria (1)
Gracilaria (122)
Gracilariophila (2)
Gracilariopsis (17)
Hydropuntia (13)
Melanthalia (3)
Figures in brackets are approx. how many species per genus.
Uses
They are economically important, as Agar can be derived from many types of red seaweeds, including those from families such as Gelidiaceae, Gracilariaceae, Gelidiellaceae and Pterocladiaceae. It is a polysaccharide located in the inner part of the red algal cell wall. It is used in food material, medicines, cosmetics, therapeutic and biotechnology industries.
References
Other sources
Bellorin AM, Buriyo A, Sohrabipour J, Oliveira MC, Oliveira EC (2008) Gracilariopsis mclachlanii sp. nov. and Gracilariopsis persica sp. nov. of the Gracilariaceae (Gracilariales, Rhodophyceae) from the Indian Ocean. J Phycol 44:1022–1032
Conklin KY, O'Doberty DC, Sherwood AR (2014) Hydropuntia perplexa, n. comb. (Gracilariaceae, Rhodophyta), first record of the genus in Hawaii. Pac Sci 68:421–434
Kamiya, M., Lindstrom, S.C., Nakayama, T., Yokoyama, A., Lin, S.-M., Guiry, M.D., Gurgel, F.D.G., Huisman, J.M., Kitayama, T., Suzuki, M., Cho, T.O. & Frey, W. 2017. Rhodophyta. In: Syllabus of Plant Families, 13th ed. Part 2/2: Photoautotrophic eukaryotic Algae. (Frey, W. Eds), pp. [i]–xii, [1]–171. Stuttgart: Borntraeger Science Publishers. ISBN 978-3-443-01094-2.
Red algae families
Edible algae | Gracilariaceae | [
"Biology"
] | 692 | [
"Edible algae",
"Algae"
] |
71,470,682 | https://en.wikipedia.org/wiki/Reverse-search%20algorithm | Reverse-search algorithms are a class of algorithms for generating all objects of a given size, from certain classes of combinatorial objects. In many cases, these methods allow the objects to be generated in polynomial time per object, using only enough memory to store a constant number of objects (polynomial space). (Generally, however, they are not classed as polynomial-time algorithms, because the number of objects they generate is exponential.) They work by organizing the objects to be generated into a spanning tree of their state space, and then performing a depth-first search of this tree.
Reverse-search algorithms were introduced by David Avis and Komei Fukuda in 1991, for problems of generating the vertices of convex polytopes and the cells of arrangements of hyperplanes. They were formalized more broadly by Avis and Fukuda in 1996.
Principles
A reverse-search algorithm generates the combinatorial objects in a state space, an implicit graph whose vertices are the objects to be listed and whose edges represent certain "local moves" connecting pairs of objects, typically by making small changes to their structure. It finds each objects using a depth-first search in a rooted spanning tree of this state space, described by the following information:
The root of the spanning tree, one of the objects
A subroutine for generating the parent of each object in the tree, with the property that if repeated enough times it will eventually reach the root
A subroutine for listing all of the neighbors in the state space (not all of which may be neighbors in the tree)
From this information it is possible to find the children of any given node in the tree, reversing the links given by the parent subroutine: they are simply the neighbors whose parent is the given node. It is these reversed links to child nodes that the algorithm searches.
A classical depth-first search of this spanning tree would traverse the tree recursively, starting from the root, at each node listing all of the children and making a recursive call for each one. Unlike a depth-first search of a graph with cycles, it is not necessary to maintain the set of already-visited nodes to avoid repeated visits; such repetition is not possible in a tree. However, this recursive algorithm may still require a large amount of memory for its call stack, in cases when the tree is very deep. Instead, reverse search traverses the spanning tree in the same order while only storing two objects: the current object of the traversal, and the previously traversed object. Initially, the current object is set to the root of the tree, and there is no previous object. From this information, it is possible to determine the next step of the traversal by the following case analysis:
If there is no previous object, or the previous object is the parent of the current object, then this is the first time the traversal has reached the current object, so it is output from the search. The next object is its first child or, if it has no children, its parent.
In all other cases, the previous object must be a child of the current object. The algorithm lists the children (that is, state-space neighbors of the current object that have the current object as their parent) one at a time until reaching this previous child, and then takes one more step in this list of children. If another child is found in this way, it is the next object. If there is no next child and the current object is not the root, the next object is the parent of the current object. In the remaining case, when there is no next child and the current object is the root, the reverse search terminates.
This algorithm involves listing the neighbors of an object once for each step in the search. However, if there are objects to be listed, then the search performs steps, so the number of times it generates neighbors of objects is within a factor of two of the number of times the recursive depth-first search would do the same thing.
Applications
Examples of the problems to which reverse search has been applied include the following combinatorial generation problems:
Vertices of simple convex polytopes
If a -dimensional convex polytope is defined as an intersection of half-spaces, then its vertices can be described as the points of intersection of or more hyperplanes bounding the halfspaces; it is a simple polytope if no vertex is the intersection of more than of these hyperplanes. The vertex enumeration problem is the problem of listing all of these vertices. The edges of the polytope connect pairs of vertices that have hyperplanes in common, so the vertices and edges form a state space in which each vertex has neighbors. The simplex algorithm from the theory of linear programming finds a vertex maximizing a given linear function of the coordinates, by walking from vertex to vertex, choosing at each step a vertex with a greater value of the function; there are several standard choices of "pivot rule" that specify more precisely which vertex to choose. Any such pivot rule can be interpreted as defining the parent function of a spanning tree of the polytope, whose root is the optimal vertex. Applying reverse search to this data generates all vertices of the polytope. A similar algorithm can also enumerate all bases of a linear program, without requiring that it defines a polytope that is simple.
Cells of hyperplane arrangements
A hyperplane arrangement decomposes Euclidean space into cells, each described by a "sign vector" that describes whether its points belong to one of the hyperplanes (sign 0), are on one side of the hyperplane (sign +1), or are on the other side (sign −1). The cells form a connected state space under local moves that change a single sign by one unit, and it is possible to check that this operation produces a valid cell by solving a linear programming feasibility problem. A spanning tree can be constructed for any choice of root cell by defining a parent operator that makes the first possible change that would bring the sign vector closer to that of the root. Using reverse search for this state space and parent operator produces an algorithm for listing all cells in polynomial time per cell.
Point-set triangulations
The triangulations of a planar point set are connected by "flip" moves that remove one diagonal from a triangulation and replace it by another. If the Delaunay triangulation is chosen as the root, then every triangulation can be flipped to the Delaunay triangulation by steps in which the triangulation of some subset of four points is replaced by its Delaunay triangulation. Choosing the first Delaunay flip as the parent of each triangulation, and applying local search, produces an algorithm for listing all triangulations in polynomial time per triangulation.
Connected subgraphs
The connected subgraphs, and connected induced subgraphs, of a given connected graph form a state space whose local moves are the addition or removal of a single edge or vertex of the graph, respectively. A spanning tree of this state space can be obtained by adding the first edge or vertex (in some ordering of the edges or vertices) whose addition produces another connected subgraph; its root is the whole graph. Applying local search to this state space and parent operator produces an algorithm for listing all connected subgraphs in polynomial time per subgraph.
Other applications include algorithms for generating the following structures:
Polyominos, polyiamond prototiles, and polyhex (mathematics) hydrocarbon molecules.
Topological orderings of directed acyclic graphs, using a state space whose local moves reverse the ordering of two elements.
Spanning trees of graphs, non-crossing spanning trees of planar point sets, and more generally bases of matroids, using a state space that swaps one edge for another.
Euler tours in graphs.
The maximal independent sets of sparse graphs.
Maximal planar graphs and polyhedral graphs.
Non-crossing minimally rigid graphs on a given point set.
Surrounding polygons, polygons that have some of a given set of points as vertices and surround the rest, using a state space that adds or removes one vertex of the polygon.
Vertices or facets of the Minkowski sum of convex polytopes.
The corners (multidegrees) of monomial ideals.
References
Search algorithms
Combinatorial algorithms | Reverse-search algorithm | [
"Mathematics"
] | 1,710 | [
"Combinatorial algorithms",
"Computational mathematics",
"Combinatorics"
] |
71,470,889 | https://en.wikipedia.org/wiki/In%20Win%20Development | In Win Development, Inc. (), formerly rendered as In-Win Development and commonly shortened to In Win or InWin, is a Taiwanese computer case and computer power supply manufacturer. In Win was founded in 1985 and has since opened multiple factories and headquarters internationally.
Corporate history
In Win Development was founded by Vincent Lai in 1985 in Taoyuan, Taiwan, with an initial investment capital of $200,000. Originally only a manufacturer of computer cases, In Win added power supplies production lines to its Taoyuan facility in the late 1980s and dabbled with manufacturing disk storage equipment and joysticks in the early 1990s.
In Win has four international branch offices between the United States, the United Kingdom, the Netherlands, and China. Europe and North America represented In Win's biggest importers of computer cases, purchasing respectively 40 percent and 30 percent of their output in 2004; the rest of their output was purchased evenly between outside territories—chiefly Asia, Africa, and the Middle East. Roughly 70 percent of the company's overall products were delivered to original equipment manufacturers and original design manufacturers, including Ingram Micro, Time Computer, Toshiba, NEC, and Intel.
In Win grew from having 60 employees in its Taoyuan facility in 1990 to 2,000 total employees globally on its payroll by 2004. Its engineering department staffed 80 employees in 2003; all engineers by that point had 15 to 20 years of hands-on and computer-aided experience designing cases. The software the engineers used to design cases at that point included AutoCAD, TurboCAD, Espirit, and Pro/E. The company planned to hire up to 500 more employees by 2005 and to open up a R&D laboratory in mainland China in 2004. Having established its American headquarters in the City of Industry, California, by the late 1990s, In Win leased another 50,000 office in a different part of the city in the fourth quarter of 2002.
By 2012 the company began primarily targeting the video-gaming demographic, as well as PC case modders, although OEMs and systems integrators both remained critical customers for the company into the 2020s. The company reached a peak revenue of NT$4 billion (US$124 million) in 2008. Sales dropped 47 percent through 2016 to $2.1 billion however.
Manufacturing facilities
The company relies on steel imported from Japan and Taiwan for use in its mid- and mini-tower cases. Formerly outsourcing the injection molding of its plastic parts, In Win purchased plastic injection machinery for its own 4,600 Taoyuan factory between 1996 and 1997. In 2000, it opened up a 17,480 plant nearby this factory in Taoyuan. Four final assembly lines 120 meters in total produced 16,000 cases per daily shift in 2004. In 2002, the company opened up a 202,400 factory in Mainland China. Initially meant for the production of In Win's computer cases, this factory branched out to providing mechanical and electrical manufacturing for systems integrators and OEMs. In Win planned to provide the same OEM services out of its Taiwan facilities by 2005. The company achieved a monthly production output of 350,000 and 400,000 PC and server cases by the end of the third quarter of 2004—70 percent of which comprising tower cases, 20 percent comprising desktop and small-form-factor cases, and 10 percent comprising server and other industrial cases.
Products
In Win was noted for its ornate case designs of some models from the mid-2000s onward; for example, the company's GunDam case introduced in 2008 was inspired by the mecha franchise of the same name. Many of In Win's cases incorporate motherboard trays to facilitate upgrades and servicing. The company was also the first to incorporate USB-C ports on front panels for a barebones computer case.
Some of In Win's more elaborate cases include the H-Frame 2.0, designed around nine stacked sheets of aluminum sandwiched between tempered glass—allowing air to pass completely through the case—and the H-Tower case, which has mechanisms to open up the case via a button or a smartphone app. The company additionally sponsors PC modding competitions in the United States. In 2017, the company released another limited-edition case—quantity 200—made of cast aluminum and 5 mm-thick tempered glass, designed large enough to run extensive water-cooled setups.
In Win, as with several other computer case manufacturers, skipped over the proposed low-profile motherboard form factor NLX in the late 1990s, citing low demand. They embraced the contemporaneous microATX specification, however, and in the late 2000s designed a modicum of microATX cases designed with optimal airflow and other thermal considerations for Intel's Atom CPU family.
Reception
In Win's 901 mini-ITX case received generally positive reviews in Custom PC and Computer Shopper—the latter calling it "the rarest of things—a genuinely attractive PC case" but with "some annoyances", while the former deemed it "more of a lifestyle chassis than a high-performance one". Computer Shopper in particular praised the placement of its slimline optical drive slot underneath the power supply housing "so as not to spoil the case's smooth front" and wrote that the interior left plenty of room for large graphics cards but wrote that the matte plastic interior was vulnerable to scratching. Custom PC meanwhile found the case thermally problematic for CPUs and GPUs with the stock fans but said that aftermarket fans resolved this and were easy to install. The magazine also praised its cable management implements and wrote that the clearance for the power supply and GPU was "massive", albeit not spacious enough for large GPUs should a 120 mm water cooler be installed to the front intake mount.
Custom PC called the company's GT1 ATX case "rock-solid" in build quality but with "some sloppy design decisions", particularly regarding the front panel's cabling and the dust filters being made from "flimsy material rather than slide-out plastic". The reviewer called the interior "sensibly laid-out" and well-accommodated for cable management but found the drive cages' inability to be removed completely preventing it a 240 mm cooling radiator from being installed at the top of the chassis, although one cage could be slid out of the way for installing taller graphics cards.
In Win's Chopin line of small-form-factor mini-ITX cases were measured by Custom PC to be only slightly larger than the motherboard in surface area and requiring a custom power supply unit. The reviewer praised the build quality and quiet operation but noted that discrete GPUs were uninstallable due to its diminutive size.
See also
Corsair Gaming
Clevo
DTK Computer
Notes
Citations
References
Further reading
External links
1985 establishments in Taiwan
Computer companies of Taiwan
Computer hardware companies
Companies based in Taoyuan City
Computer companies established in 1985
Taiwanese brands
Computer enclosure companies
Electronics companies of Taiwan | In Win Development | [
"Technology"
] | 1,417 | [
"Computer hardware companies",
"Computers"
] |
71,471,342 | https://en.wikipedia.org/wiki/Louise%20Purton | Louise E. Purton is an Australian biologist who is Professor of Medicine and head of the Stem Cell Regulation Laboratory at St. Vincent's Institute of Medical Research in Melbourne. Her research considers the stem cells responsible for the production of blood cells and the regulations of haematopoietic diseases. She was awarded the International Society for Experimental Hematology McCulloch & Till Award in 2022. She has experienced profound bilateral hearing loss since the age of three and has been recognised for her work supporting Equity and Diversity, particularly amongst women and people with disability, and is a member of the AAMRI Gender, Equity and Diversity and Inclusion group GEDI.
Early life and education
Purton was raised in Balranald, NSW. At age three she became profoundly deaf after experiencing a life-threatening illness. She had Cochlear implants inserted in 2018 and 2021. Purton was an undergraduate student at the University of Melbourne. She remained there for doctoral research, where she studied the stroll cell types in bone marrow. She moved to the United States for postdoctoral research, where she worked at the Fred Hutchinson Cancer Research Center and identified that the all-trans retinoic acid enhances the renewal of hematopoietic stem cells. She returned to Australia in 2000, when she studied the roles of various retinoic acid receptors and their roles on haematopoiesis. She showed that self-renewal is regulated by Retinoic acid receptor gamma, and loss of this receptor has intrinsic and extrinsic impacts on haematopoiesis. She returned to America in 2004, where she studied cells in the bone marrow microenvironment and how they could regulate myeloproliferative-like disorders.
Research and career
Purton's research is focused on processes involved in blood cell production (haematopoietic stem cells (HSCs).
In 2008 Purton returned to Australia, where she launched the St. Vincent's Institute of Medical Research Stem Cell Regulation Unity. She investigates the processes involved in haematopoiesis, the production of blood cells. These processes involve hematopoietic stem cells, which can either self-renew or differentiate into more mature types. Issues surrounding the regulation of hematopoietic stem cells can lead to diseases such as leukaemia. Purton investigates the roles of retinoic acid receptors in haematopoiesis. She makes use of mouse models, cell assays and gene transduction. Through these studies, she identified how blood cells are produced in bone marrow, which can impact the downstream treatment of blood cancer.
Purton has studied the role of Homeobox A1 (HOXA1) in myelodysplastic syndrome (MDS), a blood cell disease that results in bone marrow failure. Around 30% of patients with MDS progress to acute myeloid leukaemia, and the only treatment is hematopoietic stem cell transplantation. She identified that altered HOXA1 genes impact the ability of haematopoietic stem cells.
Purton was appointed Associate Editor of Experimental Hematology in 2020.
Awards and honours
2011 National Health and Medical Research Council Senior Research Fellowship
2016 SVI Foundation Award
2019 University of Melbourne Professorial Fellow
2022 International Society for Experimental Hematology McCulloch & Till Award
2022 Chair, ASH Scientific Committee on Stem Cells and Regenerative Medicine.
2023 Member, Scientific Program Committee, International Society for Experimental Hematology, Member, ASH Committee for Scientific Affairs.
2023 ISEH award for Leadership in Diversity, Equity and Inclusion.
Academic service
Purton has worked to improve diversity within the scientific community. She identified and publicised inequality in the rates of funding for men and women in Australia. For example, she identified that the National Health and Medical Research Council awarded men 23% more grants ($95 million more funding) than their female counterparts. She worked with Jessica Borger to launch a petition calling for a strategic overhaul of the NHMRC funding body.
Selected publications
References
External links
Living people
Year of birth missing (living people)
Australian biologists
University of Melbourne alumni
Australian women scientists
Stem cell researchers
Women in medicine | Louise Purton | [
"Biology"
] | 846 | [
"Stem cell researchers",
"Stem cell research"
] |
78,841,934 | https://en.wikipedia.org/wiki/Kolmogorov%20population%20model | In biomathematics, the Kolmogorov population model, also known as the Kolmogorov equations in population dynamics, is a mathematical framework developed by Soviet mathematician Andrei Kolmogorov in 1936 that generalizes predator-prey interactions and population dynamics. The model was an improvement over earlier predator-prey models, notably the Lotka–Volterra equations, by incorporating more realistic biological assumptions and providing a qualitative analysis of population dynamics.
History
The development of the Kolmogorov population model was influenced by Kolmogorov's early interest in biology during his schoolboy years. Despite being primarily known for his contributions to probability theory and information theory, Kolmogorov made several large contributions to biomathematics. The model was particularly inspired by the work of Italian physicist Vito Volterra, who had developed his predator-prey equations based on observations of fish populations in the Adriatic Sea during World War I. Volterra's work showed that during the war, when fishing was reduced due to military activities, the proportion of predator fish increased while prey fish decreased.
Definition
The Kolmogorov population model is expressed as a system of differential equations
where represents the prey population, represents the predator population, and and are continuously differentiable functions describing the growth rates of the respective populations. The rates of population change decrease as predator numbers increase:
.
The system must admit invasion by predators when prey is present in isolation; that is, , where represents the carrying capacity of the prey population.
Applications
The Kolmogorov model addresses a limitation of the Volterra equations by imposing self-limiting growth in prey populations, preventing unrealistic exponential growth scenarios. It also provides a predictive model for the qualitative behavior of predator-prey systems without requiring explicit functional forms for the interaction terms.
The model's contributions to theoretical ecology were not immediately recognized, with significant appreciation only emerging in the 1960s through the work of American ecologists Michael Rosenzweig and Robert H. MacArthur. Their research demonstrated how the model can be used to understand non-transitory oscillations in ecological systems and the conditions for local stability of predator-prey interactions.
Recent research has shown that Kolmogorov systems can exhibit complex behaviors, including the existence of strange attractors and robust permanent subsystems, implying that even deterministic predator-prey interactions can lead to unpredictable long-term dynamics.
See also
Mathematical biology
Predator-prey interactions
References
Population ecology
Mathematical modeling
Ecological theories
Population dynamics
Partial differential equations | Kolmogorov population model | [
"Mathematics"
] | 507 | [
"Applied mathematics",
"Mathematical modeling"
] |
78,841,983 | https://en.wikipedia.org/wiki/Dan%20%28mass%29 | Dan (), or Daam in Cantonese, Tan in Japanese and Taiwanese, also called "Chinese hundredweight" or "picul", 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 dan equals 100 jin or 50 kg in mainland China, 60 kg in Taiwan and Japan,
and 60.478982 kg in Hong Kong, Singapore and Malaysia.
Dan is mostly used in the traditional markets.
China Mainland
On June 25, 1959, the State Council of the People's Republic of China issued the Order on the Unified Measurement System, with minor amendment to the market system. "
Legally, 1 dan equals 100 jins, 50 kg, or 110.2 lb.
Taiwan
The so-called Taiwan dan is actually the dan used throughout China during the Qing Dynasty. 1 Taiwan dan is 60 kg, equal to 100 Taiwan jin.
Hong Kong and Macau
Hong Kong law stipulates that one dan is equal to one hundred jin , which is 60.478982 kg.
Singapore and Malaysia have similar regulations as Hong Kong, as they are all former British colonies.
Japan
In Japan, 1 dan, or tan in Japanese pronunciation, is equal to 60 kg.
See also
Chinese units of measurement
Hong Kong units of measurement
Taiwanese units of measurement
Japanese units of measurement
Notes
References
Sources
, reprinted by the Louisiana State University Press at Baton Rouge in 1991.
External links
中國度量衡#衡
市制
擔
英擔
https://en.wiktionary.org/wiki/公擔#Chinese 公擔
Units of mass
Chinese units of measurement
Customary units of measurement | Dan (mass) | [
"Physics",
"Mathematics"
] | 343 | [
"Matter",
"Quantity",
"Units of mass",
"Mass",
"Customary units of measurement",
"Units of measurement"
] |
78,842,078 | https://en.wikipedia.org/wiki/Transient%20masculinization | Transient masculinization (or transient virilization) is a biological phenomenon in which female individuals of certain species temporarily exhibit physical or behavioral traits typically associated with males. Unlike permanent masculinization, which results in lifelong male-like characteristics, transient masculinization is limited to specific developmental stages or life events and often regresses over time. These traits may include altered genital morphology, increased androgen levels, or male-typical behaviors that serve adaptive purposes within specific ecological and social contexts.
The fossa (Cryptoprocta ferox), a carnivorous mammal endemic to Madagascar, is a well-documented example of transient masculinization. Juvenile female fossas develop masculinised genitalia, such as an enlarged clitoris resembling a penis, which diminishes as they reach sexual maturity. This phenomenon is hypothesized to reduce male harassment during vulnerable developmental stages, among other potential benefits.
Transient masculinization is distinct from other forms of sexual dimorphism or masculinization and has been observed in a small but ecologically diverse range of species. Studying this phenomenon sheds light on the complex interplay between hormones, behavior, and evolutionary pressures shaping sex-specific traits.
Biological Mechanisms
Transient masculinization is driven by complex hormonal processes that result in temporary expression of male-typical physical or behavioral traits in females. The phenomenon is primarily mediated by the endocrine system, particularly the secretion and regulation of androgens such as testosterone. These hormones influence the development of masculinised traits during specific life stages or contexts, and their effects diminish when hormonal levels subside, or regulatory mechanisms change.
Androgens, such as testosterone and dihydrotestosterone (DHT), play a pivotal role in masculinization. During transient masculinization, elevated androgen levels are observed in females during critical developmental windows. For instance, in juvenile female fossas (Cryptoprocta ferox), increased androgen levels drive the development of an enlarged clitoris and scrotum-like structures, which regress as androgen levels decline with maturity.
Other species, such as ring-tailed lemurs (Lemur catta), demonstrate transient increases in androgen levels during specific reproductive stages, influencing behaviors like aggression and dominance. These fluctuations are tightly regulated to ensure that masculinized traits do not interfere with reproductive capacity or other female-specific roles.
Transient masculinization typically occurs during juvenile stages or limited periods in adulthood. The timing is critical for the functional significance of these traits. For example:
In fossas, masculinization during juvenile stages may reduce male harassment, giving young females a developmental advantage.
In other species, transient masculinization during reproductive stages can enhance competitive behaviors or social dominance in females.
Unlike permanent masculinization, transient masculinization is reversible. The traits regress as hormonal levels return to baseline or as the organism transitions to a new life stage. This reversibility is believed to involve shifts in the sensitivity of androgen receptors, as well as changes in the synthesis and metabolism of androgens. Comparisons with species exhibiting permanent masculinization, such as spotted hyenas, reveal key differences. In transiently masculinised species, androgen exposure is temporary and typically does not involve structural changes to the ovaries or long-term suppression of female reproductive function. These differences suggest that transient masculinization is an adaptive, flexible response to specific ecological or social pressures.
Species Examples
Transient masculinization has been documented in a small group of species, with the fossa being the most extensively studied. Below are examples illustrating the phenomenon and its potential adaptive significance:
Fossa (Cryptoprocta ferox)
The fossa, a carnivorous mammal endemic to Madagascar, provides one of the clearest examples of transient masculinization. Juvenile female fossas exhibit masculinised genitalia, including an enlarged clitoris supported by an os clitoridis (a bony structure) and scrotum-like swellings. These traits regress as the individuals approach sexual maturity, at which point the clitoris shrinks, and the scrotum-like swellings flatten.
The adaptive function of this transient masculinization remains under study. One hypothesis suggests that it reduces sexual harassment from adult males, as masculinised traits may cause young females to be mistaken for males. This could provide developmental protection during a vulnerable life stage.
Ring-Tailed Lemur (Lemur catta)
In ring-tailed lemurs, transient masculinization is evident in seasonal fluctuations of androgen levels in females, particularly during breeding seasons. Elevated androgens correlate with increased aggression and dominance behaviors, which may enhance access to resources or mates. Unlike permanent masculinization, these traits are hormonally mediated and dissipate after the breeding season.
Evolutionary Significance and Ecological Contexts
Transient masculinization, though rare, has important evolutionary and ecological implications in species where it occurs. It is thought to serve adaptive functions related to social dynamics, reproductive success, and survival. The phenomenon provides insight into the flexible nature of sexual dimorphism and how organisms can modulate traits in response to ecological pressures. Below are key hypotheses regarding the evolutionary significance of transient masculinization:
Reduction in Sexual Harassment
One of the leading hypotheses for transient masculinization is that it reduces sexual harassment from adult males. In species like the fossa, juvenile females exhibit masculinised genitalia, which may cause confusion in adult males, leading them to mistake the females for males. This misidentification can help young females avoid unwanted mating attempts and aggression during vulnerable life stages. The regression of masculinised traits with age ensures that the female can later engage in reproduction without hindrance.
In species like the ring-tailed lemur, transient masculinization in the form of increased aggression or dominance behaviors may similarly prevent females from being marginalized in social hierarchies. This could grant females greater access to resources and mates.
Enhancing Competitive Ability
Transient masculinization may also enhance a female's ability to compete for resources or mates. In species with complex social hierarchies, such as lemurs and meerkats (Suricata suricatta), temporary masculinization (via increased androgen levels) can boost aggression, thereby increasing a female's competitive edge. During breeding seasons, these enhanced traits might facilitate access to high-quality mates, ensuring reproductive success. This temporary masculinization is often regulated to ensure that it does not disrupt the female's overall reproductive health.
Flexibility in Social Systems
Transient masculinization may reflect the adaptive flexibility of sex-specific traits within social systems. The ability to exhibit male-typical traits temporarily, without permanent changes to reproductive anatomy or function, provides a flexible strategy to navigate environmental or social pressures. For example, in species where female competition is seasonal, the ability to display male-like traits only when needed (e.g., during periods of high competition) allows females to balance their role in reproduction with social dominance.
This flexibility may be especially important in species with fluctuating social dynamics or in environments where the risk of male harassment is higher during certain times.
Evolutionary Trade-Offs
Some researchers suggest that transient masculinization could represent an evolutionary trade-off between reproductive success and survival. By temporarily displaying male-like traits, females may avoid predation or social conflict, but they might also risk reduced mate attraction or reproductive success. Such trade-offs underscore the complex interplay between evolutionary pressures on both sexes and the adaptive strategies that evolve as a response to these pressures.
Comparisons with Permanent Masculinization
While transient masculinization involves the temporary expression of male-typical traits in females, permanent masculinization refers to long-lasting or irreversible morphological and/or behavioral changes in females that align them more closely with males. The key differences between these two phenomena relate to their hormonal regulation, evolutionary significance, and impact on female reproductive health. Below are the main contrasts between transient and permanent masculinization:
Duration and Reversibility
The most significant distinction between transient and permanent masculinization is the duration of the masculinised traits. Transient masculinization is temporary, with masculinised characteristics often regressing as hormone levels return to baseline or as the individual matures. For example, in the fossa, juvenile females exhibit masculinised genitalia, which shrink as they approach sexual maturity, while in species like ring-tailed lemurs, transient masculinization occurs during specific seasonal periods or reproductive windows.
In contrast, permanent masculinization results in irreversible changes, such as in the case of the spotted hyena (Crocuta crocuta), where females possess masculinised genitalia throughout their lives, including a large, pseudopenis-like clitoris. These structural changes are maintained across all life stages.
Hormonal Regulation
Both forms of masculinization are driven by androgens such as testosterone, but the regulation and timing of androgen exposure differ. In transient masculinization, androgen levels rise temporarily during specific developmental periods or reproductive stages. For example, during the juvenile period, fossa females experience a surge in androgens, causing masculinised genitalia and behavior, but these levels drop as the individual matures. Similarly, in ring-tailed lemurs, transient masculinization correlates with seasonal hormonal fluctuations.
In contrast, permanent masculinization typically results from prolonged or consistent exposure to high androgen levels throughout the individual's life. In spotted hyenas, females are exposed to elevated androgens in utero and during early development, leading to the permanent formation of male-like genitalia. This long-term exposure to androgens may also affect the development of other male-typical behaviors such as dominance or aggression.
Evolutionary and Ecological Functions
While both forms of masculinization serve evolutionary functions, they do so in distinct ways. Transient masculinization may primarily be a response to social or environmental pressures. In species like the fossa, the temporary masculinization of juvenile females may reduce male harassment and give females more time to grow and develop without interference. Similarly, in ring-tailed lemurs, seasonal masculinization allows females to compete more effectively during breeding seasons, when reproductive competition is highest.
Permanent masculinization, on the other hand, typically evolves when consistent selective pressures favor the persistence of male-typical traits in females. In the case of spotted hyenas, the development of a pseudopenis is thought to play a role in dominance hierarchies, where females exert control over the social structure. Permanent masculinization also plays a role in reproduction, as hyena females must "give birth" through their pseudopenis, a trait that is closely linked to their reproductive physiology.
Impact on Female Reproductive Health
One of the most significant distinctions between transient and permanent masculinization is their impact on female reproductive health. In cases of transient masculinization, the hormonal changes and resulting traits are typically temporary and do not cause long-term disruption to reproductive function. For example, in the fossa, masculinization occurs during a critical growth phase but does not impede future reproductive capabilities.
Permanent masculinization, however, can affect reproductive anatomy and function. In hyenas, the pseudopenis is a result of permanent masculinization and is associated with complex reproductive and social behaviors. The presence of this structure is crucial for mating, but it can also complicate childbirth, as hyena females must give birth through their pseudopenis.
Research History
The study of transient masculinization in mammals is relatively recent, with its documentation expanding primarily in the last few decades. Although sexual dimorphism in mammals has been well established, the phenomenon of transient masculinization, in which females temporarily exhibit male-like traits, remained largely unexplored until the late 20th and early 21st centuries. Researchers have identified both ecological and hormonal mechanisms underlying these traits, though the full scope and evolutionary significance are still areas of active research.
Early Observations and Documentation
The first significant documentation of transient masculinization in a mammal came from the study of the fossa, a carnivorous mammal endemic to Madagascar. In 2002, a study observed that juvenile female fossas exhibit masculinised genitalia, including an enlarged clitoris and scrotum-like swellings, which regress as the female's approach sexual maturity. Their research provided the first clear evidence of transient masculinization in mammals and prompted further inquiries into its adaptive significance.
Theoretical Developments and Hypotheses
After the discovery in the fossa, a number of hypotheses emerged to explain the function of transient masculinization. These theories typically revolved around sexual selection, social dynamics, and reproductive strategies. The concept that transient masculinization could serve as a form of protection against sexual harassment or aggression from adult males gained traction, particularly in species with pronounced sexual dimorphism. In species like the fossa and ring-tailed lemurs, the hypothesis that masculinised traits temporarily reduce male attention during vulnerable juvenile stages became a central focus for future studies.
Research also began to focus on the role of hormonal fluctuations in regulating these temporary masculinised traits. It was recognized that androgen levels, such as testosterone, likely play a key role in driving the development of masculinised characteristics, but only during specific periods of development or reproduction.
Expanding Knowledge and Comparative Studies
In the years following the fossa study, researchers expanded the scope of transient masculinization beyond the fossa to other species. Comparative studies involving species like meerkats and ring-tailed lemurs have provided further insights into the hormonal and social factors influencing this phenomenon. These studies have allowed scientists to investigate whether transient masculinization is a widespread strategy in the animal kingdom or if it is an uncommon adaptive trait.
The development of more sophisticated endocrine assays, improved field observation techniques, and advances in molecular biology have allowed researchers to test the hormonal underpinnings of transient masculinization in greater detail. In particular, studies on female spotted hyenas, a species exhibiting permanent masculinization, have shed light on the evolutionary advantages of both permanent and transient masculinization in response to social competition and reproductive dynamics.
See also
Sexual dimorphism
Sexual selection
Evolution of sexual reproduction
Masculinization / Virilization
Comparative endocrinology
Female Masculinization Hypothesis
References | Transient masculinization | [
"Physics",
"Biology"
] | 3,069 | [
"Sex",
"Sexual dimorphism",
"Symmetry",
"Asymmetry"
] |
78,842,081 | https://en.wikipedia.org/wiki/L-687%2C414 | L-687,414 is a glycine-site NMDA receptor antagonist or low-efficacy partial agonist ( ≈ 10%) which is used in scientific research. It a close analogue of HA-966. The drug has been found to produce hyperlocomotion (a psychostimulant-like effect), analgesia or antinociceptive effects, anticonvulsant effects, and neuroprotective effects in animals. In contrast to uncompetitive NMDA receptor antagonists like ketamine and phencyclidine (PCP), L-687,414 has not been associated with the development of brain vacuoles (i.e., Olney's lesions) in animals.
Trace amine-associated receptor 1 (TAAR1) partial and full agonists, including RO5166017, RO5203648, RO5256390, and RO5263397, have been found to reverse the hyperlocomotion induced by L-687,414 as well as by other NMDA receptor antagonists like PCP in rodents. Similarly, glycine transporter 1 (GlyT1) inhibitors reverse the hyperlocomotion induced by L-687,414 in rodents. As such, TAAR1 agonists and GlyT1 inhibitors may have antipsychotic-like properties.
References
Alcohols
Amines
Experimental drugs
Ketones
NMDA receptor antagonists
Pyrrolidines | L-687,414 | [
"Chemistry"
] | 321 | [
"Ketones",
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
78,842,263 | https://en.wikipedia.org/wiki/Al-Majdi%20fi%20Ansab%20al-Talibiyyin | Al-Majdi fi Ansab al-Talibiyyin (, ) is an Arabic book written by Ali ibn Muhammad Alawi Umari known as Ibn Sufi on the subject of genealogy dating back to the fifth century AH11th century AD/CE. In this work, the author discusses the genealogy of the descendants of the Alawis and the Talebis, especially the genealogy of the first Shiite Imam, Ali and his descendants. Almost a thousand years have passed since the life of this handwritten manuscript book.
About the author
"Ali ibn Muhammad Alawi Umari" with the full name of "Najmuddin Abul-Hasan Ali ibn Abul-Ghanaim Alawi Umari" known as "Ibn Sufi" (born AD/CE AH in Basra, died AD/CE AH in Mosul) was a prominent Shiite genealogist. The famous Arabic historical genealogy book "Al-Majdi fi Ansabi al-Taalebiyin" (in , ) was his most important work in his entire lifetime.
Ibn Sufi was born and raised in Basra, and is known as "Umari" and also "Alawi" due to his ancestry to his grandfather, "Umar al-Atraf", the son of the first Shia Imam, "Ali", known as "Ibn Taghlibiyah". Ibn Sufi's father, "Abu al-Ghana'im Muhammad", known as "Ibn Mahlabiyah", was considered as an authority on the genealogy science. In fact, genealogy had a long history in Ibn Sufi's family, and even his sixth grandfather, "Muhammad Sufi", to whom Ibn Sufi is attributed and who was killed by order of Harun al-Rashid (the fifth Abbasid caliph of the Abbasid Empire), was also a genealogist. It seems that Ibn Sufi spent most, if not all, of his time in Baghdad between 1016 AD/CE to 1029 AD/CE (407 AH to 420 AH). Ibn Sufi migrated from Basra to Mosul in 1032 AD/CE (423 AH), where he married and settled down. Ibn Sufi, in his account of the lineage of Zayd ibn Ali, referred to Twelver school of thought as his own sect. According to Ibn al-Tiqtaqa (a prominent historian) in his book "Al-Asili", Ibn Sufi died in Mosul.
As Ibn Sufi himself says, from childhood he studied various sciences, especially genealogy, and benefited from the presence of great masters. Ibn Tawus (a Shiite jurist, theologian, historian and astrologer) considered Ibn Sufi as the foremost genealogist of his time, and according to Ibn Inabah (a Shiite historian and genealogist), Ibn Sufi's statement in the field of genealogy was a proof. Ibn Sufi traveled to many lands and cities to gain experience and knowledge in sciences specially in genealogy, such as Ramla, Nusaybin, Levant, Mayafarfin, Egypt, Oman, Kufa, and Ukbara. Ibn Sufi has also been introduced by some historians as a writer, poet, and jurist.
The subject of the book
The book "Al-Majdi fi Ansab al-Talibiyyin" includes the genealogy of the Islamic Prophet Muhammad and his family, especially the twelve Shiite Imams. The subject of this book is the genealogy of Sadat. Authentic Shia hadiths have been used to prove the ratios mentioned in the book.
The book "Al-Majdi fi Ansab al-Talibiyyin" was an important work on the subject of the Islamic genealogy dates back to the fifth century AH11th century AD/CE, in which the author discusses the genealogies of the descendants of the Alawites and Talebites, especially the genealogy of the first Shia Imam, Ali, and his descendants.
The content
The author first briefly discusses the lineage of the Islamic prophet Muhammad and then discusses the lineage of Abu Talib ibn Abd al-Muttalib's family. The three main parts of the book include the genealogy of the three sons of Abu Talib ibn Abd al-Muttalib, namely Ali, Jafar, and Aqil, and the description of the genealogy of the family of Ali, the first Shiite Imam, occupies a larger part.
At the beginning of the description of Ali's lineage, the author also mentions his daughters and then introduces the lineage of Ali's first son and the second Imam of the Shiites, Hassan ibn Ali, then introduces the lineage of Ali's second son and the third Imam of the Shiites, Hussein ibn Ali, then introduces the lineage of Ali's third son Muhammad ibn al-Hanafiyya, then introduces the lineage of Ali's another son Abbas ibn Ali (Abu al-Fadl), and then introduces the lineage of Ali's another son Umar al-Atraf, who is the grandfather of the author of the book. Also, in the genealogy section of the descendants of Ali's second son, Hussein ibn Ali, the genealogies of the descendants of other Shiite Imams are briefly mentioned. In describing the lineage of each Shiite Imam, the author also provides a brief description of him, with a little more explanation about the twelfth Shiite Imam, Muhammad al-Mahdi.
This book contains the genealogy of the Alawites and Talebites who migrated to lands outside the Hijaz and Iraq, some of whom gained fame and status.
The book begins with brief information about the genealogy of the Messenger of God, Islamic Prophet Muhammad. At the beginning of the book, it is mentioned that the Islamic Prophet Muhammad, was born in the year known as the Year of the Elephant (approximately equating to 570 CE) in Mecca in pre-Islamic Arabian, and his father, Abdullah ibn Abd al-Muttalib, died before his birth, and he lost his mother at the age of six, and at the age of twenty, he participated in the Battle of Fijar, and at the age of twenty-five, he married Khadija bint Khuwaylid, and at the age of sixty-three, he died of poisoning, and his tomb is in Medina.
The last section of the book is about the genealogy of the descendants of Aqil ibn Abi Talib (an elder brother of Ali). This section mentions that Aqil ibn Abi Talib's nickname is "Abu Yazid" and that he had 18 sons. The final article in the book is about the genealogy of Aqil ibn Abi Talib's grandson, "Ja'far ibn Abdullah ibn Aqil", who died in Harran in 946 CE334 AH, and the final matter in the book is about his children who lived in Aleppo, Beirut, and Egypt.
Importance of the book
The book "Al-Majdi fi Ansab al-Talibiyyin" enjoyed considerable fame and prestige during the lifetime of its author and was popular in the East and West of the Islamic world. This work is a classic and educational text in Islamic genealogy, and Islamic genealogists consider it obligatory for elders to read it. In many Islamic genealogy books dating back to the fifth and sixth century AH11th and 12th century AD/CE, the book "Al-Majdi fi Ansab al-Talibiyyin" is cited and quoted. This shows that the author of the book, Ibn Sufi, was trusted by other genealogists of the time.
About the name of the book
The book "Al-Majdi fi Ansab al-Talibiyyin" is Ibn Sufi's most important book, written in the study of the lineage of the family of the prophet of Islam Muhammad, and the Shiite Imams. Ibn Sufi traveled to Egypt in 1051 AD/CE (443 AH), where he presented some of his works to "Majd al-Dawlah Abul-Hassan Ahmad" (president of the House of Wisdom of the time), during the Fatimid Empire. "Abu Talib Muhammad", the son of "Majd al-Dawlah Abul-Hassan Ahmad", asked Ibn Sufi to write a brief book on genealogy. Ibn Sufi also attributed the book to him in recognition of the kindness of "Majd al-Dawlah" and called it "Al-Majdi" in the first phrase of the book name which means "Attributed to Majdi" or "Dedicated to Majdi". So, the book name literally means "Dedicated to Majdi in the Lineages of the Talibis Peoples". "Talibis Peoples" was a family tree in an Arab clan within the Quraysh tribe to which the Islamic prophet Muhammad Ibn Abdullah belonged. In fact, "Talibis Peoples" refers to Abi Talib's lineages and descendants.
This book is known among Islamic genealogists as the abbreviated name of "Al-Majdi".
About the citations in the book
In old Arabic manuscripts, after each matter, it was stated who and from what source the matter was quoted or narrated. This action was called "Quoting" or "Narrating" (in ). "Narrating" also means word-of-mouth transmission. In ancient Arab times, the credibility of a manuscript depended on the quotes and narrations it used. If the narrator was known in society as a truthful and trustworthy person, then his statement would be considered as a valid proof. Therefore, the manuscripts that referred to reliable people and materials enjoyed a special reputation.
The book "Al-Majdi fi Ansab al-Talibiyyin" has many citations from reliable and trustworthy persons and matters in the field of genealogy. So, the book "Al-Majdi fi Ansab al-Talibiyyin" was famous in Islamic world among genealogists because of its reliable narrations and it's trustworthy author. Ibn Sufi, the author of the book "Al-Majdi fi Ansab al-Talibiyyin", used the narrations he gave through his father, "Ibn Mahlabiyah", and through "Ubaydoli" (a reliable prominent genealogist). In the book "Al-Majdi fi Ansab al-Talibiyyin", the author has narrated from the books, manuscripts, and commentaries belonging to the following individuals too:
The remained manuscripts
The book "Al-Majdi fi Ansab al-Talibiyyin" was originally a manuscripts on the ancient handwriting paper. In fact, there have been several manuscripts of it. Some of the book's manuscripts have become defective and worn out over time, or have been burned in the fanatic conflicts. The surviving manuscripts which remains in the world include:
The academic printed version
In 1989 AD/CE (1409 AH), all the available original Arabic manuscripts of the book "Al-Majdi fi Ansab al-Talibiyyin" were collected and revived in the city of Qom (the headquarters city of the Islamic scholars in Iran), and a modern-style academic version was republished with an introduction, commentaries, footnotes, and an afterword which is written by various experts. In this version, the main genealogy matters comes in Arabic language same as the original manuscripts sources, but it is a multi-language version which has many parts such as introduction, commentaries and afterword which comes in Persian language.
In the famous version of this book which is available in the Iranian book markets, the introduction was written by Mahmoud Mar'ashi Najafi (an Iranian librarian, Bibliographer and manuscript expert), in which he describes the biography of the author, Ibn Sufi. The researches and guiding commentaries was done by Ahmad Mahdavi Damghani (an Iranian scholar and university professor), and most of the useful footnotes were mentioned by him. There is also a detailed introduction at the beginning of the book and comments and explanations at the end of the book, written by Ahmad Mahdavi Damghani too. The researcher in the field of ancient texts and the person who had an effective role in the revival of Shiite works "Abdulaziz Mohaqqiq Tabatabaei", wrote an separate book in the commentaries of the book "Al-Majdi fi Ansab al-Talibiyyin" too.
See also
Umdat al-Talib
Ibn Sufi
Ibn Inabah
Salawat
Islamic honorifics
Revelation
Atlas of Shia
Du'a al-Sabah
References
External links
Al-Majdi fi Ansab al-Talibiyyin in Google books
Al-Majdi Fi Ansab Al-Talibin on Kutub Ltd.
Al-Majidi Fi Ansab Al-Talibeen By Najm Al-Din Abi Al-Hassan Ali Bin Muhammad Bin Muhammad Al-Alawi Al-Omari Al-Nasabah
Family of Muhammad
Muslim family trees
Family trees
1400s books
2000s books
Shia Islam
Genealogy
Family history
Medieval genealogies and succession lists
Genealogy publications
Kinship and descent
Descent from antiquity
Family trees of royalty
History of Shia Islam
Shia literature
Books about Islam
11th-century books
Medieval Arabic literature
11th-century Arabic-language books
Oral history books
Religious biographical dictionaries
Books of Islamic biography | Al-Majdi fi Ansab al-Talibiyyin | [
"Biology"
] | 2,753 | [
"Behavior",
"Phylogenetics",
"Genealogy",
"Human behavior",
"Kinship and descent"
] |
78,844,718 | https://en.wikipedia.org/wiki/Ga-68-Trivehexin | 68Ga-Trivehexin is a radiotracer for positron emission tomography (PET), obtained by labeling the peptide conjugate Trivehexin with the a positron emitting radionuclide gallium-68 (68Ga). 68Ga-Trivehexin targets (i.e., binds to) the cell surface receptor αvβ6-integrin, a heterodimeric transmembrane cell adhesion receptor whose primary natural ligand is latency associated peptide (LAP) in its complex with transforming growth factor beta 1 (TGF-β1). Binding of αvβ6-integrin to LAP releases and thus, activates TGF-β1. 68Ga-Trivehexin is applied for PET imaging of medical conditions associated with elevated αvβ6-integrin expression, which are concomitant with elevated TGF-β1 activity. As an activator of the tumor suppressor TGF-β1, αvβ6-integrin is often overexpressed in tumors and fibrosis tissues, which is why 68Ga-Trivehexin PET imaging is primarily relevant in this medical context.
Chemistry
Trivehexin, the radiolabeling precursor
Like most precursors used for radiolabeling with radioactive metal cations, Trivehexin is composed of a dedicated complex ligand (a so-called chelator) for kinetically inert binding of the 68GaIII ion, and the bioligand(s) for binding to αvβ6-integrin. The chelator comprised in Trivehexin is a triazacycloalkane with 3 phosphinic acid substituents, with the basic structure 1,4,7-triazacyclononane-1,4,7-triphosphinate (frequently abbreviated TRAP). The αvβ6-integrin binding structure is a cyclic nonapeptide with the amino acid sequence cyclo(YRGDLAYp(NMe)K).
In the Trivehexin molecule, three of these cyclopeptides are covalently bound to the TRAP chelator core. Since TRAP possesses three equivalent carboxylic acids for attachment of other molecular units (so-called conjugation) via amide formation, Trivehexin is a C3-symmetrical molecule with its three peptide bioligands being fully equivalent. The peptides are attached to the chelator core via the terminal amine group of the side chains of N-methyl lysine. Actually, the conjugation is not done by amide bonding directly, but involves prior functionalization of the peptide with a short molecular extension (a linker) bearing a terminal alkyne, and of TRAP with three linkers bearing terminal azides. These components are assembled by means of copper(I) catalyzed alkyne-azide cycloaddition (CuAAC, also known as Huisgen reaction, a Click chemistry reaction), giving rise to the three 1,3-triazole linkages in the 68Ga-Trivehexin structure.
68Ga radiolabeling
68Ga-Trivehexin is a radioactive drug. The radioactive atom, gallium-68 (68Ga), decays with a half-life of approximately 68 min to the stable isotope zinc-68 (68Zn), to 89% by β+ decay whereby a positron with a maximum kinetic energy of 1.9 MeV is emitted (the remaining 11% are EC decays). Due to the short half life, 68Ga-Trivehexin can not be manufactured long before use but the 68Ga has to be introduced into the molecule shortly before application. This process is referred to as radiolabeling, and is done by complexation of the trivalent cation 68GaIII by the TRAP chelator in Trivehexin.
68GaIII is usually obtained from a dedicated mobile radionuclide source, a Gallium-68 generator, in form of a solution in dilute (0.04–0.1 M) hydrochloric acid (frequently and imprecisely referred to as "68Ga chloride solution in HCl" despite it contains no species with a Ga–Cl bond but [68Ga(H2O)6]3+ complex hydrate cations). For radiolabeling, the pH of the 68Ga containing generator eluate has to be raised from its initial value (depending on HCl concentration, pH 1–1.5) to pH 2–3.5 using suitable buffers, such as sodium acetate. Then, Trivehexin (5–10 nmol) is added to the buffered 68Ga-containing solution, and the mixture is briefly heated to 50–100 °C (usually 2–3 min) to finalize the complexation reaction.
Use as medical imaging agent
αvβ6-Integrin as molecular target
The abundance of αvβ6-Integrin on most adult human cell types and respective tissues is low. It is however overexpressed in the context of several medical conditions, such as cancer or fibrosis, particularly idiopathic pulmonary fibrosis.
In line with the finding that αvβ6-integrin is expressed by epithelial cells, an elevated density of αvβ6 is observed on the cell surfaces of many carcinomas (synonymous to cancers of epithelial origin). Hence, 68Ga-Trivehexin can be used for PET imaging of αvβ6-integrin positive cancers (i.e., those whose cells possess a sufficiently high density of αvβ6 on their surface), including but not limited to pancreatic ductal adenocarcinoma, non-small cell lung cancer, squamous cell carcinomas (SCC) of different origin (most notably, oral and esophageal SCC), as well as breast, ovarian, and bladder cancer.
68Ga-Trivehexin has a high binding affinity to αvβ6-integrin (IC50 = 0.047 nM). Its affinity to other RGD-binding integrins is much lower (IC50 for αvβ3, αvβ8, and α5β1 are 2.7, 6.2, and 22 nM, respectively; note that for IC50, higher values mean lower affinity), resulting in a high selectivity for αvβ6-integrin.
Imaging procedure
Since 68Ga is a positron emitter, 68Ga-Trivehexin is applicable for PET imaging. However, PET is rarely used as a standalone imaging technique these days because most clinics use PET/CT or even PET/MRI systems, which provide more detailed and useful medical information to the physician.
For clinical PET/CT diagnostics, an activity in the range of 80–150 MBq 68Ga-Trivehexin is injected intravenously (i.v.). The tracer then distributes in the body and specifically binds to its target αvβ6-integrin, while an excess is excreted via the kidneys and the urine. As a result, 68Ga-Trivehexin and, therefore, the positron-emitting radionuclide 68Ga, is preferably accumulated by αvβ6-integrin abundant tissues (for example, tumor tissue). Next, a PET/CT scanner is used to detect the gamma radiation which is generated by the annihilation of the positrons emitted by 68Ga (not the actual positrons, which do not leave the body but travel only a few millimetres through the tissue). The spatial distribution of the annihilation events is 'reconstructed' (calculated) from the raw detector data (referred to as listmode data), which eventually delivers a 3-dimensional representation of αvβ6-integrin positive tissues of interest. Typically, the PET/CT imaging is performed 45–60 minutes after the i.v. administration of 68Ga-Trivehexin.
PET/CT imaging of cancers
68Ga-Trivehexin has not yet obtained a marketing approval. It is used for clinical imaging of αvβ6-integrin expression in experimental settings. First-in-human application of different αvβ6-integrin radiotracers has demonstrated that 68Ga-Trivehexin performed especially well in detecting pancreatic cancer, showing high uptake in tumor lesions and low background in the gastrointestinal tract (GI tract). 68Ga-Trivehexin has been used for clinical PET/CT imaging in single cases and two cohorts (12 and 44 patients, respectively) of pancreatic ductal adenocarcinoma, as well as in cases of tonsillar carcinoma metastasized to the brain, of bronchial mucoepidermoid carcinoma,
of disseminated parathyroid adenoma in the context of the diagnosis of primary hyperparathyroidism (PHPT),
and of papillary thyroid carcinoma.
Safety
Like for other radioactive imaging agents in medicine, the applied amounts of radioactivity are so low that radiation-related adverse effects are very unlikely to occur, and have not been observed in practice. Consistent with the "tracer principle", the amount of pharmacologically active compound injected to a patient in the course of such an examination is extremely low. Adverse events, such as toxicity or allergic reactions, are thus highly improbable. No adverse or clinically detectable pharmacologic effects were observed following intravenous administration of 68Ga-Trivehexin when administered to cancer patients, and there were no significant changes in vital signs, laboratory study results, or electrocardiograms. In a study involving healthy volunteers, researchers again reported no adverse or clinically detectable pharmacologic effects and no significant changes in vital signs.
References
Positron emission tomography
Amides
Chelating agents
Nine-membered rings
Gallium
Phosphinates
Isotopes of gallium
Nonapeptides
Triazoles | Ga-68-Trivehexin | [
"Physics",
"Chemistry"
] | 2,146 | [
"Antimatter",
"Matter",
"Isotopes of gallium",
"Positron emission tomography",
"Functional groups",
"Isotopes",
"Chelating agents",
"Amides",
"Process chemicals"
] |
78,844,737 | https://en.wikipedia.org/wiki/Lenacil | Lenacil is a uracil-derived chemical herbicide used to control dicotyledons. Its formula is .
Production and synthesis
Lenacil was first patented and manufactured by DuPont in the 1960s.
The compound can be produced via a condensation reaction between ethyl-2-oxocyclopentanecarboxylate and cyclohexylurea under an environment of phosphoric acid:
Uses
Lenacil is used in the agricultural industry as a selective herbicide to protect sugar and fodder beets.
Toxicity
Lenacil is noted as a potential endocrine disrupting compound. It is not acutely toxic or genotoxic to mammals, though there is limited evidence the compound is carcinogenic. Lenacil is noted as particularly damaging to algae and aquatic plants, which is a concern if the compound leaches into groundwater when used as a pesticide.
References
Herbicides
Pyrimidinediones
Cyclopentenes
Cyclohexylamines
Ureas | Lenacil | [
"Chemistry",
"Biology"
] | 214 | [
"Organic compounds",
"Herbicides",
"Biocides",
"Ureas"
] |
78,845,077 | https://en.wikipedia.org/wiki/Capability%20Hardware%20Enhanced%20RISC%20Instructions | Capability Hardware Enhanced RISC Instructions (CHERI) is a computer processor technology designed to improve security. CHERI aims to address the root cause of the problems that are caused by a lack of memory safety in common implementations of languages such as C/C++, which are responsible for around 70% of security vulnerabilities in modern systems.
The hardware works by giving each reference to any piece of data or system resource its own access rules. This prevents programs from accessing or changing things they should not. It also makes it hard to trick a part of a program into accessing or changing something that it should be able to access, but at a different time. The same mechanism is used to implement privilege separation, dividing processes into compartments that limit the damage that a bug (security or otherwise) can do.
CHERI can be added to many different instruction set architectures including MIPS, AArch64, and RISC-V, making it usable across a wide range of platforms.
Software must be recompiled to use CHERI, but most software requires few (if any) changes to the source code. CHERI’s importance has been recognised by governments as a way to improve cybersecurity and protect critical systems. It is under active development by various business and academic organizations.
Background
CHERI is a capability architecture. Early capability architectures, such as the CAP computer and Intel iAPX 432, demonstrated secure memory management but were hindered by performance overheads and complexity. As systems became faster and more complex, vulnerabilities like buffer overflows and use-after-free errors became widespread. CHERI addresses these challenges with a design intended for modern computing environments. It enforces memory safety and provides secure sharing and isolation to handle increasing software complexity and combat cyberattacks.
Mechanism
A CHERI system operates at a hardware level by providing a hardware-enforced type (a CHERI capability) that authorises access to memory. This type includes an address and other metadata, such as bounds and permissions. Instructions such as loads, stores, and jumps, that access memory use one of these types to authorise access, whereas on traditional architectures they would simply use an address.
This metadata is stored inline, alongside the address, in the computer's memory is protected by a tagged bit, which is cleared if the capability is tampered with. This informs the computer of which areas of memory can be accessed through a specific operation and how a program can modify or read memory through that operation. This allows CHERI systems to catch cases where memory that was outside the bounds of where the program was supposed to read or write to was operated on. Associating the metadata with the value used to access memory, rather than with the memory being accessed (in contrast to a memory management unit) means that the hardware can catch cases where a program attempts to access a part of memory that it should have access to while intending to access a different piece of memory.
Implementations of CHERI systems also include modifications to the default memory allocator. A memory allocator is a component that defines that a range of addresses should be treated by the programmer as an object. On a CHERI system, it must also communicate this information to the hardware, by setting the bounds on the pointer (represented by a CHERI capability) that is returned. It may also communicate the lifetime, to prevent use-after-free or use-after-reuse bugs.
Depending on the context, CHERI systems can be used to enhance compiler-level checks, build secure enclaves, or even be used to augment existing instruction architectures. A report by Microsoft in 2019 found that CHERI’s protections could be used to mitigate over 70% of memory safety issues found in 2019 at the company. CHERI architectures are also designed to be backward compatible with existing programming languages such as C and C++. A study performed by University of Cambridge researchers found that porting six million lines of C and C++ code to CHERI required changes to 0.026% of the Lines-of-Code (LoC).
Limitations
The architecture introduces hardware complexity due to the tag-bit mechanisms and capability checks required for enforcing memory safety. Although optimisations have been implemented to minimise these impacts, the performance trade-offs can vary depending on specific workloads and specific implementations. Additionally, CHERI requires modifications to both software and hardware ecosystems. Implementations such as Morello allow unmodified binaries to run but these do not get any additional security benefits. Software must be recompiled or adapted to utilise CHERI’s capability-based model, and hardware manufacturers must incorporate CHERI extensions into their designs.
Standardisation remains an ongoing effort. While initiatives such as the CHERI Alliance and RISC-V standardisation aim to establish broader support, the lack of widely accepted industry standards for CHERI features have delayed adoption. Adapting legacy software or retrofitting existing systems to work with CHERI can be challenging, particularly for large and heterogeneous codebases. The difficulty often stems from programming practices used during the software's original development, such as implementing custom memory management, where identifying pointers from integers can be particularly problematic.
CHERI Implementations
The CHERI architecture has been implemented across multiple platforms and projects:
Morello: Developed by Arm as part of the UKRI-funded Digital Security by Design (DSbD) programme, the Morello chip is a superset architecture designed to evaluate experimental CHERI features for potential production use on the AArch64 architecture. The Morello board supports CheriBSD, custom versions of Android, and Linux. It remains a research prototype.
CHERIoT: Introduced by Microsoft in 2023 and now developed by multiple vendors, CHERIoT is a RISC-V CHERI adaptation optimised for small embedded devices. CHERIoT is a hardware-software co-designed project and builds a custom RTOS and compartment model along with specialised hardware to provide string security guarantees. It incorporates advanced memory safety features inspired by the CHERI temporal safety projects performed on Morello.
Sonata: Developed by lowRISC and manufactured by NewAE as part of the UKRI-funded Sunburst project, the Sonata platform is an FPGA-based system designed to run RISC-V architectures. The board has an open-source design, allowing researchers and developers to modify and adapt its hardware and software. Sonata is primarily designed as a prototyping system for CHERIoT.
ICENI: Announced by SCI Semiconductors in 2024, ICENI is a CHERIoT-compatible microcontroller designed for secure embedded systems.
CHERI implementations that target mainstream operating systems, are designed to accommodate both legacy and pure capability software, to allow for gradual adaptation for existing applications. CHERI has also been implemented across various hardware architectures in a research setting, including MIPS, AArch64 (via the Morello platform), and RISC-V.
History
In the 1970s and 1980s early capability architectures such as the CAP computer (developed at the University of Cambridge) and the Intel iAPX 432 demonstrated strong security properties. These systems relied on indirection tables to manage capabilities, introducing performance bottlenecks as memory access required multiple lookups. While this approach worked when processors were slow and memory was fast, it became impractical by the mid-1980s as processors became faster and memory access times lagged behind.
In 2010 DARPA launched the Clean-slate design of Resilient, Adaptive, Secure Hosts (CRASH) programme, which tasked participants with redesigning computer systems to improve security. SRI International and University of Cambridge team revisited capability architectures, seeking to address memory safety challenges inherent in conventional designs.
By 2012 early CHERI prototypes were presented, These prototypes ran a microkernel with hand-written assembly for manipulating capabilities. CHERI was designed to be easy to implement on modern superscalar pipelined architectures. Unlike earlier capability systems, CHERI eliminated the need for indirection tables, avoiding the associated performance issues and proving that modern capability architectures could be efficiently implemented.
In 2014 CHERI hardware demonstrated its ability to run a full UNIX-like operating system, FreeBSD. This demonstration showed that CHERI’s capability model can integrate with existing software ecosystems. CHERI was originally prototyped as an extension to MIPS-64. The implementation used 256-bit capabilities, containing fields for a 64-bit base, length, object type, and permissions, with some bits reserved for experimental purposes.
In 2015 CHERI introduced a new capability encoding model that separated the address (referred to as a cursor) from the bounds and permissions. This refinement allowed capabilities to function as pointers in compiled C code, improving usability. That same year, Arm joined the project and provided critical feedback, highlighting that while doubling pointer sizes might be acceptable, quadrupling them would not. This feedback led to the development of CHERI Concentrate, a compressed encoding model that reduced capability size to 128 bits by eliminating redundancy between the base, address, and top.
In 2019 CheriABI demonstrated a fully memory-safe implementation of POSIX, allowing existing desktop software to become memory safe with a single recompile.
By 2020 it became evident that software vendors were reluctant to port their software without hardware vendor support, while hardware vendors were unwilling to produce chips without sufficient customer demand. UK Research and Innovation (UKRI) launched the Digital Security by Design (DSbD) programme to address adoption barriers for CHERI. The programme allocated £70M, matched by £100M of industrial investment, to build the CHERI software ecosystem.
This initiative funded Arm’s Morello chip, a superset architecture designed to evaluate experimental CHERI features for potential production use based on AArch64. The Morello board was designed to run CheriBSD, as well as custom versions of Android and Linux. At the same time, the Cornucopia project demonstrated that CHERI could enforce both spatial and temporal memory safety, offering deterministic protection against heap object temporal aliasing (roughly, "use-after-free"). The follow-up project, Cornucopia Reloaded, showcased efficient temporal safety using page-table features in Morello, in particular, near-negligible pause times for the application making use of revocation.
In 2023 Microsoft introduced CHERIoT, a RISC-V CHERI adaptation optimised for small embedded devices. CHERIoT incorporated ideas from Cornucopia and memory colouring techniques such as SPARC ADI and Arm MTE to enhance security. As part of the UKRI-funded Sunburst project, lowRISC launched the Sonata platform to advance RISC-V-based CHERI development and support standardisation efforts. Both the CHERI RISC-V research work and CHERIoT fed into the standardisation process for an official CHERI family of RISC-V extensions. Codasip announced that they had RISC-V IP cores with CHERI extensions available to license.
By 2024 SCI Semiconductors announced ICENI, a CHERIoT-compatible chip designed specifically for secure embedded systems. Codasip is actively developing a Linux kernel implementation for the RISC-V architecture. The CHERI Alliance, a non-profit organisation based in Cambridge, UK, was established to promote the adoption of CHERI technology and its integration into secure digital products and systems, including Google as a founding member.
References
Capability systems
Computer architecture
Computer memory
Memory management
Operating system security | Capability Hardware Enhanced RISC Instructions | [
"Technology",
"Engineering"
] | 2,355 | [
"Capability systems",
"Computer engineering",
"Computer architecture",
"Computer systems",
"Computers"
] |
78,847,059 | https://en.wikipedia.org/wiki/Law%20of%20constancy%20of%20interfacial%20angles | The law of constancy of interfacial angles (; ) is an empirical law in the fields of crystallography and mineralogy concerning the shape, or morphology, of crystals. The law states that the angles between adjacent corresponding faces of crystals of a particular substance are always constant despite the different shapes, sizes, and mode of growth of crystals. The law is also named the first law of crystallography or Steno's law.
Definition
The International Union of Crystallography (IUCr) gives the following definition: "The law of the constancy of interfacial angles (or 'first law of crystallography') states that the angles between the crystal faces of a given species are constant, whatever the lateral extension of these faces and the origin of the crystal, and are characteristic of that species." The law is valid at constant temperature and pressure.
This law is important in identifying different mineral species as small changes in atomic structure can lead to large differences in the angles between crystal faces.
The sum of the interfacial angle (external angle) and the dihedral angle (internal angle) between two adjacent faces sharing a common edge is radians (180°).
History
The law of the constancy of interfacial angles was first observed by the Danish physician Nicolas Steno when studying quartz crystals (De solido intra solidum naturaliter contento, Florence, 1669), who noted that, although the crystals differed in appearance from one to another, the angles between corresponding faces were always the same.
The law was also observed by Domenico Guglielmini (Riflessioni filosofiche dedotte dalle figure de Sali, Bologna, 1688), but it was generalized and firmly established by Jean-Baptiste Romé de l'Isle (Cristallographie, Paris, 1783) who accurately measured the interfacial angles of a great variety of crystals, using the goniometer designed by Arnould Carangeot and noted that the angles are characteristic of a substance. Carangeot was a student of Romé de L’Isle at the time of his invention of the basic crystallographic measuring instrument.
A French crystallographer, René Just Haüy, showed in 1774 that the known interfacial angles could be accounted for if the crystal were made up of minute building blocks (molécules intégrantes) that correspond approximately to the present-day unit cells.
In the diagram, the green dodecahedron on the left is built from cubical units, with the faces having a Miller index of (210). Unlike the regular dodecahedron on the right, its faces are not regular pentagons, but they are close to regular in appearance. The piling of the cubical units forms the pentagonal dodecahedron of pyritohedral pyrite. The decrement of the layers is in the proportion of 2:1, which leads to a dihedral angle at the top edge pq of 126° 87′, closely corresponding to that of the empirical crystal, of 127° 56′. The diagram is based on an 1801 drawing by René Just Haüy.
Crystal structure
The phenomenon of the constancy of interfacial angles is important because it is an outward sign of the inherent symmetry and ordered arrangement of atoms, ions or molecules within a crystal structure. The faces of a crystal are parallel to the planes of the crystal lattice, and it is for this reason that the interfacial angles are the same in different crystal specimens.
The angles between the various faces of a crystal remain unchanged throughout its growth. Crystals grow by addition of material to existing faces, this material being deposited parallel to the already existing surfaces. Consequently, if more material is added to one face than to another, the faces become unalike in size and shape, nevertheless the interfacial angles between them remain the same.
Crystals generally exhibit anisotropy, that is their properties are dependent on their direction. In particular, crystals cleave in specific directions, namely those parallel to the planes of the lattice structure. Cleavage preferentially occurs parallel to higher density planes with low Miller indices.
See also
Law of rational indices
References
Crystallography
Mineralogy concepts
Scientific laws | Law of constancy of interfacial angles | [
"Physics",
"Chemistry",
"Materials_science",
"Mathematics",
"Engineering"
] | 860 | [
"Mathematical objects",
"Scientific laws",
"Equations",
"Materials science",
"Crystallography",
"Condensed matter physics"
] |
78,847,602 | https://en.wikipedia.org/wiki/Nephroarctin | Nephroarctin is a naturally occurring depside compound found in certain foliose lichens, most notably Nephroma arcticum from which it was first isolated in 1969. Along with its related compound phenarctin, it is one of two structurally unusual compounds produced by N. arcticum, both characterised by an uncommonly high number of single-carbon attachments to their core structure. This colourless crystalline substance, with the molecular formula C20H20O7, consists of two benzene rings connected by an ester linkage and plays a role in the lichen's defensive mechanisms. The compound is particularly concentrated in the thallus tips of N. arcticum and N. occultum, with levels varying seasonally in correlation with photosynthetic activity.
History
The chemical investigation of Nephroma arcticum began in the late 19th century with Hesse's isolation of usnic acid and a hydrocarbon called nephrin (C20H32). Zopf later expanded this work by identifying the triterpene compound zeorin. A significant breakthrough came in 1959 when Clifford Wetmore reported a supposed "carotenoid" compound present in 58% of examined specimens – a substance later revealed to be a nephroarctin derivative.
Nephroarctin was first isolated by Mariko Nuno from specimens collected on Mount Ontake in central Honshu, Japan. The structural elucidation was accomplished through collaborative work between the Iatrochemical Research Foundation and Takeda Chemical Industries, with assistance from the lichenologists Yasuhiko Asahina and Shoji Shibata of the University of Tokyo. The compound can be isolated from lichen thalli through a multi-step chemical process. After removal of zeorin through acetone treatment, the compound is purified using silica gel chromatography with a benzene-ethyl acetate mixture. During this separation, chloronephroarctin elutes after usnic acid but before zeorin and an unidentified compound.
Distribution and occurrence
Nephroarctin occurs primarily in two foliose lichen species. It was first discovered in Nephroma arcticum and later identified in N. occultum, where it coexists with phenarctin, usnic acid, and zeorin. Both species show identical nephroarctin patterns when analysed by thin-layer chromatography, producing characteristic spots at Rf 0.51 and 0.61 that fluoresce under ultraviolet light and show distinctive colour reactions with sulfuric acid, potassium hydroxide, and p-phenylenediamine reagents.
Within individual lichen thalli, nephroarctin's distribution is notably uneven. Concentrations are approximately 90% higher in apical thallus tips compared to basal zones. This spatial variation appears linked to type, as parts containing green algal photobionts show significantly higher concentrations (5.6 ± 0.7 mg/g) compared to cephalodial parts containing cyanobacteria (2.3 ± 0.4 mg/g). This distribution pattern suggests nephroarctin serves a protective function, defending photobiont-rich regions against lichen-eating gastropods.
The compound's presence is particularly characteristic of N. arcticum specimens containing green algal photobionts, distinguishing them from Nephroma species that contain cyanobacterial (genus Nostoc) photobionts. Temporally, nephroarctin levels show seasonal fluctuation, typically increasing from July to August in correlation with periods of higher photosynthetic activity. This pattern suggests its production may be regulated by the availability of photosynthates and the overall metabolic activity of the lichen.
Chemical structure and properties
Molecular structure
Nephroarctin is a depside compound whose structure was determined through a combination of spectroscopic analysis and X-ray crystallography. The molecule consists of two benzene rings connected by an ester linkage, with an unusually large number of C1 substituents on both rings.
Physical properties
In its purified form, nephroarctin appears as colourless prismatic crystals with a melting point originally reported as ; in a 1996 source, it is given with a broader range, .
Chemical reactivity
The compound shows fluorescence under UV light and demonstrates characteristic colour reactions in lichen spot tests: deep yellow with p-phenylenediamine (PD), reddish-brown with ferric chloride in alcohol, and yellow to orange-yellow with potassium hydroxide (K/KC). The homofluorescein reaction is "reluctantly positive".
Spectroscopic characteristics
The compound's spectroscopic profile includes UV absorption maxima at 238, 281, 315, and 379 nm, with additional maxima at 202, 254, and 344 nm
Derivatives
Several chemical derivatives of nephroarctin have been prepared and characterised:
Hexa-acetate derivative (C32H32O13): Formed through acetylation, appears as colourless crystals with a melting point of .
Monobromonephroarctin (C20H19BrO7): Produced through bromination, forms colourless prisms with a melting point of 186–187°C. The crystal structure of this derivative was instrumental in confirming the complete structure of nephroarctin, crystallising in the space group P2₁/c with unit cell parameters a = 15.25 Å, b = 14.73 Å, c = 18.18 Å, and β = 104° 15'.
Hyponephroarctin (C2OH2206): Has a melting point of .
2'-0-Methylnephroarctin: Has a melting point of .
1'-Chloronephroarctin (C20H19Cl07): Has a melting point of .
Synthesis
The first total synthesis of nephroarctin was reported in 1976, driven by interest in nephroarctin and phenarctin's unusual structural features – particularly their large number of C1 substituents, with phenarctin being the only known fully substituted depside at the time. The key step involved the condensation of 3-methoxy-2,5,6-trimethylphenol (the A-component) with 3,5-diformyl-2,4-dihydroxy-6-methylbenzoic acid (the S-component) in the presence of trifluoroacetic anhydride.
The S-component was prepared from methyl haematommate through Gattermann formylation followed by treatment with boron tribromide. The A-component was obtained by catalytic reduction of rhizinonaldehyde. The final condensation reaction proceeded with a 23% yield to give synthetic nephroarctin that was identical to the natural product.
References
Cited literature
Lichen products | Nephroarctin | [
"Chemistry"
] | 1,464 | [
"Natural products",
"Lichen products"
] |
78,848,189 | https://en.wikipedia.org/wiki/HR%203600 | HR 3600 (HD 77475) is a bluish-white hued variable star in the southern constellation of Vela. It has the variable-star designation IZ Velorum (abbreviated to IZ Vel). With an apparent magnitude of about 5.54, it is faintly visible by the naked eye under dark skies. It is located approximately distant according to Gaia EDR3 parallax measurements, and is receding from the Solar System at a heliocentric radial velocity of 22.8 km/s.
Physical properties
This is a hot, luminous B-type main-sequence star with a mass of 4.0 and a radius of 3.2 . With an effective temperature of , it shines at an absolute bolometric magnitude of −2.08, meaning it radiates 535 from its photosphere; and an absolute visual magnitude of −0.71, that is 151 released in the visual (V) band of the UBV photometric system.
This star was initially given the stellar classification B5III in 1978, indicative of a blue giant, but was reclassified as a main-sequence star of the same spectral type by Burki et al. (1982) due to similarities to other stars such as 32 Orionis, Lambda Columbae, HW Velorum, and HD 186837, all of type B5V. They simultaneously reported that it was a slowly pulsating B-type star (SPB) with three tentative periods of 9.64 days, 14.4 days, and 10.7 days, all of them with amplitudes of several mmag that produce a combined peak-to-peak amplitude of roughly 0.03 mag.
In 1986, Balona & Laing stated that HR 3600 in fact only had a single period of 1.10 days, an alias of the 9.64-day period presented by Burki et al. Citing the variable radial velocity of the star (20-30 km/s) and the low projected rotational velocity (50 km/s), they argued that it was more likely a rotating ellipsoidal variable, in which case the system would consist of a close binary orbiting each other every 2.20 days. In 1994, Balona, who continued to observe the variable, revised the period to 0.905 days (or possibly 1.81 days), which was another alias of the 9.64-day period. The 14.4-day period could not be detected. The low rotational velocity contradicts with the hypotheses that the variability is caused by either binarity or rotational modulation, so the exact nature of this star has yet to be determined.
References
B-type main-sequence stars
Slowly pulsating B-type stars
Vela (constellation)
3600
CD−41 04720
077475
044299
J09012085-4151513
Velorum, IZ | HR 3600 | [
"Astronomy"
] | 613 | [
"Vela (constellation)",
"Constellations"
] |
78,850,749 | https://en.wikipedia.org/wiki/List%20of%20Sigma%20Gamma%20Tau%20chapters | Sigma Gamma Tau is the American honor society in aerospace engineering. The society formed from the merger of Tau Omega and Gamma Alpha Rho in 1953. It has chartered more than fifty chapters in the United States. With the merger of the two societies, Sigma Gamma Tau started with fourteen chapters, renamed for their host institution. Following is a list of Sigma Gamma Tau chapters, with inactive institutions indicated in italics.
Notes
References
Engineering honor societies
Lists of chapters of former Association of College Honor Societies members by society | List of Sigma Gamma Tau chapters | [
"Engineering"
] | 100 | [
"Engineering societies",
"Engineering honor societies"
] |
78,850,791 | https://en.wikipedia.org/wiki/Pretoria-Pietersburg%20railway%20line | The Pretoria-Pietersburg railway line was built between 1897 and 1899 from Pretoria to Pietersburg (now Polokwane) by the Pretoria Pietersburg Railway Company with British capital. Five months after the railway was completed, the Second Anglo-Boer War broke out and the ZAR government took control of the railway.
After the war, it came under the control of the Central South African Railways.
Construction
Construction started in 1897 and on 1 July 1898, the first 132 km between Pretoria and Nylstroom was opened. Three months later, the next 90 km between Nylstroom and Potgietersrus was opened and on 31 May 1899, the last 63 km between Potgietersrus and Pietersburg was opened. The railway begins at Pretoria Station, where it connects to the NZASM railway network. It passes the city to the west and follows the Apies River to Hammanskraal. As the Apies River and Pienaars River turn west, the railway continues northwards to Warmbad, where it ascends to Nylstroom. It then turns northeast and follows the Nyl River to Potgietersrus. From there, it crosses the Waterberg and descends to Pietersburg.
On 31 May 1902, when the railway came under British control, its official length was 176 miles and 58 chains (284.4 km).
Second Anglo-Boer War
On 12 October 1899, a few months after the railway had been opened, the Second Anglo-Boer War broke out. The ZAR government took control of the railway and placed it under the management of the NZASM with Mauritz de Wildt as manager. De Wildt was also the chief engineer of NZASM at the time. After British forces under the command of Lord Roberts occupied Pretoria on 31 May 1900, the ZAR government moved to Machadodorp and railway carriages were used as government offices and also to store state archives.
After President Kruger left for Europe, the ZAR government moved to Pietersburg. Carriages on the Warmbad-Pietersburg section of the railway were used by the ZAR government until 30 March 1901. At the same time, repairs were made to the Pretoria Warmbad section of the line. On 1 April, Nylstroom was occupied by the Australian forces, Potgietersrus was occupied on 5 April, and Pietersburg was occupied on 8 April. The railway then came under the control of the Imperial Military Railways (IMR). In addition to normal railway services, the trains also provided a mobile post office service.
The IMR trains were attacked at least twice by Boer commandos. On 4 July 1901, a Boer commando under the command of General CF Beyers attacked a train at Tobiasspruit, 8 km north of Naboomspruit. On 10 August 1901, another Boer commando, this time under the command of Captain Jack Hindon and Captain Henri Slegtkamp, attacked an armoured train at Haartebeeslaagte, 11 km south of Naboomspruit. After the Treaty of Vereeniging (31 May 1902), the railway line came under the control of the Central South African Railways.
Financing
In 1895, a concession was granted to Hendrik Jacobus Schoeman to build and operate the railway line. In 1896, the Pretoria-Pietersburg Railway Company Limited was founded with a capital of £500,000 in the United Kingdom and listed on the London Stock Exchange to operate the concession. Further financing was obtained by issuing bonds worth .
Between 31 May 1899 and 13 October 1899, passengers and 7,402 tons of freight were transported by the railway. The income during this period was and the expenditure (excluding interest on its bonds) was .
On 14 November 1903, the company was dissolved by the British Government. The British government refunded the shareholders their original capital and also paid for the company's assets. In terms of the Hague Convention (1898), compensation was paid to them for income guaranteed by the ZAR government. The amount due in taxes was eventually settled in the English High Court in 1908.
Locomotives
The PPS ordered a total of 15 locomotives, but before the last four were delivered, the Second Boer War broke out, and the PPS merged with the NZASM. While the railway was under construction, four saddle tank locomotives were purchased for construction and shunting work. Three 26 tonner 0-6-0ST locomotives were purchased directly from the manufacturer, and one locomotive, a 0-4-0ST, was second-hand from the NGR. The PPS took delivery of six mainline locomotives – five 2-6-4T tank locomotives, which were newly purchased, and a second-hand 4-6-0T tank locomotive, which was bought from the Delagoa Bay Railway. A sixth tank locomotive was lost during the sea voyage between the United Kingdom and Southern Africa. The replacement locomotive was delivered in 1900 at Lourenco Marques.
In 1898, three 4-8-0 tender locomotives were ordered. These locomotives, based on the 7th Class of the Cape Government Railways, were delivered to the Imperial Military Railways in 1900. In 1898, a 46-ton locomotive was also obtained from NZASM. It was named "Prinsloo."
Notes
References
Rail transport in South Africa
Trains | Pretoria-Pietersburg railway line | [
"Technology"
] | 1,080 | [
"Trains",
"Transport systems"
] |
78,851,123 | https://en.wikipedia.org/wiki/BD%2B05%204868 | BD+05 4868 is a binary star consisting of a K-dwarf and an M-dwarf. Around the primary one rocky planet is detected. This planet, called BD+05 4868Ab, orbits the star so close that it disintegrates, creating a large comet-like tail, seen in transits.
BD+05 4868 was first cataloged in the Bonner Durchmusterung and in 1961 the star was identified as a proper motion star by Giclas et al. In 1984 its spectrum was observed for the first time, identifying it as a K5: type star. The star was first identified as a binary from Gaia data. The common proper motion and parallax indicate that the pair is physically bound. The binary was also detected with the Las Cumbres Observatory Global Telescope (LCOGT) 2 m Faulkes Telescope North and with Keck NIRC2.
Planetary system
The planet BD+05 4868Ab was discovered with TESS in transits. The transits are unusually deep with variable depths of 0.8-2.0%. The transits are also asymmetric, with a short ingress followed by a long egress. The researchers were also able to detect the transits in ground-based ASAS-SN and LCOGT 2m telescope data. Seven spectra of the primary were obtained with the WIYN 3.5m Telescope, detecting no radial velocity signal larger than a few m/s.
The researchers interpret the transits as a disintegrating rocky planet, similar to Kepler-1520b, KOI-2700b and K2-22b. The difference is that BD+05 4868Ab is around a relative bright (V=10.16 mag) host star and the transits are consistently deep. Other disintegrating rocky planets show weaker transits (~0.5% transit depth) that are also variable. This makes BD+05 4868Ab a compelling target for transmission spectroscopy, which could characterize exoplanet mineralogy.
The planet also has a relative low equilibrium temperature of , which could lead to differences in dust properties, when compared to other disintegrating planets. The transit shows both a leading and a trailing tail, which helped to constrain the grain sizes to be at around 1–10 μm. Comparisons to models suggest that the planet began with a mass that could be larger than the mass of Mercury. The planet lost mass due to the evaporation of minerals on the surface over several billion years. The current mass and radius of the planet is not known, but the researchers assume a mass of about (about lunar-mass) and a radius of 2,000 km (about that of Kepler-37b) in their modelling. Currently the mass-loss rate is at per billion years, meaning it will evaporate in about 2 Myrs.
References
BD+05 4868
Exoplanets discovered in 2025
Pegasus (constellation)
Transiting exoplanets
Exoplanets discovered by TESS
Sub-Earth exoplanets | BD+05 4868 | [
"Astronomy"
] | 651 | [
"Pegasus (constellation)",
"Constellations"
] |
78,852,372 | https://en.wikipedia.org/wiki/Ministry%20of%20Climate%20Change%2C%20Environment%20and%20Energy | The Ministry of Climate Change, Environment and Energy () is a Maldivian government ministry that is tasked with safeguarding and preserving the Maldives ecosystems and biodiversity as well as promoting sustainable energy resources.
It is headquartered in Dharubaaruge following the Maldives government buildings fire.
Ministers
References
Government ministries of the Maldives
Environment ministries
Energy ministries | Ministry of Climate Change, Environment and Energy | [
"Engineering"
] | 68 | [
"Energy organizations",
"Energy ministries"
] |
78,852,394 | https://en.wikipedia.org/wiki/Cobog%C3%B3 | Cobogó is the term generally given to the hollow wall-filling element present in some Brazilian buildings, typically made out of clay or cement. Its purpose is to enable increased airflow and light to enter the interior of a building, whether residential, commercial, or industrial.
The name derives from the initials of the surnames of three engineers from Recife who jointly conceptualized the blocks at the beginning of the 20th century (1929–1930): Amadeu Oliveira Coimbra, Ernest August Boeckmann, and Antônio de Góis.
In many parts of the Brazilian Northeast, the name has undergone variations, transforming into forms such as combobó, combogó, comogó, comongol, comogol, or even comungó.
Initially, cobogós were made exclusively of cement, but their popularization introduced a wider variety of materials, such as clay and glass, along with diverse forms and decorative hollow patterns.
References
History of Recife
Culture of Brazil
Architectural elements
Masonry | Cobogó | [
"Technology",
"Engineering"
] | 201 | [
"Building engineering",
"Construction",
"Architectural elements",
"Components",
"Masonry",
"Architecture"
] |
78,853,709 | https://en.wikipedia.org/wiki/Tau%20Omega | Tau Omega () was an American professional fraternity for aeronautical engineering. It was established at the University of Oklahoma in Norman, Oklahoma in 1927. Tau Omega was the first professional fraternity for aviation. In 1953, it merged with Gamma Alpha Rho to form Sigma Gamma Tau, a national aeronautical engineering society.
History
Tau Omega was established as a professional fraternity in December 1927 by students who were interested in flying instruction at the University of Oklahoma. Its founders were Warren E. Daniel, Orville Gulker, James E. "Jimmie" Haizlip, J. Court Hayes, and Earl O. Weining.
Tau Omega was the first professional fraternity for aeronautics. Haizlip was its first president. Its purpose was promoting an interest in aviation amongst college men. Membership was open to students studying aviation.
By January 1928, students at three other universities had petitioned to form a chapter of Tau Omega. In February 1928, the fraternity was chartered as a "National Honorary Aeronautical Engineering Fraternity". In 1932, Beta chapter was established at the University of Wichita.
The fraternity expanded to include nine chapters and more than 1,000 alumni. On February 28, 1953, it merged with Gamma Alpha Rho, a similar organization, to form Sigma Gamma Tau.
Symbols and traditions
The fraternity's insignia was a key shaped like a Maltese cross, with a superimposed airplane engine and propellor. On the horizontal arms of the cross were the Greek letters and . One the vertical arms of the cross were a covered wagon and lamp of learning on the cross, symbolizing the pioneering spirit and knowledge required for the field of aeronautics.
Tau Omega's motto was Quid Pro Quo. Its magazine was The Contact.
Its pledges were required to wear goggles and a white flying helmet the day before being initiated as members. Its initiation traditions included a daybreak airplane ride.
Activities
As early in as 1927, Tau Omega started the first flying school in Norman, Oklahoma; the school was not connected to the University of Oklahoma which started its own flying school in 1940.
Tau Omega members built and tested airplanes. In March 1928, members of the Alpha chapter rebuilt an airplane that belonged to the Oklahoma Air Transport Company. In December 1929, the fraternity began constructing a glider with hopes of setting a new endurance record. The glider was featured at an aerial display at the University of Oklahoma in March 1930. In April 1931, the fraternity began designing and building a monoplane to be completed in December.
In October 1931, the fraternity built a wind tunnel to be used by University of Oklahoma students for testing miniature airplane models. Members also studied engines, including a Curtis D-12 airplane engine that was loaned to the fraternity by the United States Navy in May 1933.
Chapters
Following are the chapters of Tau Omega.
Notable members
Bennett Griffin, aviator
Herbert A. Lyon, United States Air Force Major General in charge of the Space and Missile Test Center at Vandenberg Air Force Base
Clarence Syvertson, director of the Ames Research Center of the National Aeronautics and Space Administration
John Young, astronaut and lunar explorer
References
Engineering honor societies
Student organizations established in 1927
1927 establishments in Oklahoma
Merged fraternities and sororities
Professional fraternities and sororities in the United States
Student societies in the United States
Aviation organizations based in the United States
1953 disestablishments in the United States | Tau Omega | [
"Engineering"
] | 673 | [
"Engineering societies",
"Engineering honor societies"
] |
78,854,296 | https://en.wikipedia.org/wiki/Darboux%20transformation | In mathematics, the Darboux transformation, named after Gaston Darboux (1842–1917), is a method of generating a new equation and its solution from the known ones. It is widely used in inverse scattering theory, in the theory of orthogonal polynomials, and as a way of constructing soliton solutions of the KdV hierarchy. From the operator-theoretic point of view, this method corresponds to the factorization of the initial second order differential operator into a product of first order differential expressions and subsequent exchange of these factors, and is thus sometimes called the single commutation method in mathematics literature. The Darboux transformation has applications in supersymmetric quantum mechanics.
History
The idea goes back to Carl Gustav Jacob Jacobi.
Method
Let be a solution of the equation
and be a fixed strictly positive solution of the same equation for some . Then for ,
is a solution of the equation
where
Also, for ,
one solution of the latter differential equation is and its general solution can be found by d’Alembert's method:
where and are arbitrary constants.
Eigenvalue problems
Darboux transformation modifies not only the differential equation but also the boundary conditions. This transformation makes it possible to reduce eigenparameter-dependent boundary conditions to boundary conditions independent of the eigenvalue parameter – one of the Dirichlet, Neumann or Robin conditions. On the other hand, it also allows one to convert inverse square singularities to Dirichlet boundary conditions and vice versa. Thus Darboux transformations relate eigenparameter-dependent boundary conditions with inverse square singularities.
References
Theoretical physics
Ordinary differential equations | Darboux transformation | [
"Physics"
] | 334 | [
"Theoretical physics"
] |
78,854,485 | https://en.wikipedia.org/wiki/Hymenochaete%20microcycla | Hymenochaete microcycla is a species of fungus in the genus Hymenochaete.
References
Hymenochaetaceae
Fungus species
Fungi described in 1844
Taxa named by Joseph-Henri Léveillé | Hymenochaete microcycla | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
78,854,502 | https://en.wikipedia.org/wiki/Voron%202.4 | Voron 2.4 (Russian: ворон, raven) is a CoreXY 3D printer released in May 2020. It has open-source software and hardware, and requires building by the user based on parts sourced individually or in kits from third-party vendors. The printer has been described as a resurgence of the RepRap culture.
An active user community maintains the specification, shares experiences, improvements and modifications. This contributes to continuous improvement, and there are several types of adaptations, extensions and further developments (for example, the StealthBurner interchangeable tool head).
Voron 2.4 has a reputation for being complex to build and requiring considerable effort to operate. In return, its open specification and extensive use of off-the-shelf software makes it highly maintainable, modular, and extensible.
History
The Voron project was started by Russian Maks Zolin (pseudonym russiancatfood, RCF) who wanted a better, faster, and quieter 3D printer. He built a printer and started the company MZ-Bot based on open source ideology.
In 2015, the Voron Geared Extruder was released as the first design to use the Voron name. In 2015, Zolin sold the first 18 printers as kits (Voron 1.0, later renamed Voron Trident, and quite similar to the later Voron Legacy), and marked them with serial numbers. In March 2016, the first Voron printer was publicly released via the company MZ-Bot.
The V24 was an experimental model with a build volume of 24×24×24" (610×610×610 mm). Only two were built, laying the foundation for the later Voron2. By February 2019, over 100 Voron2 printers had been built and serialized, and a year later in 2020, the number had increased to 350 Voron2 printers. The Voron2.0 was never officially launched.
Zolin found that he did not want to run a company and instead decided to release his work freely, inviting others to collaborate with him. The tradition of marking new builds with serial numbers has lived on, and users who build their own Voron printer can be assigned their own serial number as proof of the hard work they have put into sourcing parts, assembling, and configuring the printer.
In May 2020, Voron2.4 was launched, and over 2500 printers were registered with serial numbers before the 2.4R2 version was launched in February 2022.
Design
The Voron 2.4 is available as standard in the 250, 300 and 350 versions, which have build volumes of 250×250×250 mm (~15 L), 300×300×300 mm (~27 L) and 350×350×350 mm (~42 L), respectively. It features a closed build chamber, which provides stable temperatures that are favorable for certain types of 3D printing filament, reduces noise, and allows for controlled exhaust emissions (HEPA filter extensions are available).
The CoreXY design results in less moving mass, allowing for higher accelerations and speeds. The belt is based on the CoreXY pattern, but with the belts stacked on top of each other and without the crossover found in some other CoreXY designs, which allows for favorable motor placement. The build manual emphasizes that the two belts should be of the same make and have exactly the same length to achieve consistent tension.
The frame is constructed from lightweight and rigid 2020 aluminum profiles with 6 mm slots, which must meet certain requirements. Linear-motion guide rails of type MGN7, MGN9 or MGN12 are used along the three axes (alternatively guide rods can be used). The recommended belts are Gates Unitta 6 mm and/or 9 mm. A single stack of F695 flange bearings is often used for belt idlers, as the bearings are much larger than standard GT2 belt idlers.
Voron 2.4 has a flying gantry, which differs from most other "pioneer" CoreXY printers (like RatRig, VzBot and Voron Trident). In other words, the 2.4 model has a stationary print plate and separate belts for moving the print head along the z-axis, while most other CoreXY printers on the other hand have a fixed gantry and a print plate that moves vertically with lead screws. A stationary print plate gives the possibility to use a heavier print plate (for example of thick steel instead of thin aluminium) that warps less when heated. It also gives a more space efficient frame, and makes it easier to calibrate the print to be parallel with the build plate (less need for bed mesh trimming). A disadvantage is that the z-axis may sag when the printer is not in use, but it shall straighten itself again when the printer is turned on.
All movement control is done with Klipper software on a Raspberry Pi, which provides great flexibility and extensibility through various parameters that can be programmed in a configuration file. The printer has the option of automatic calibration to compensate for unevenness in the build plate.
Construction and operation
The Voron 2.4 can be used for both hobby and professional small-scale production and prototyping. If using high-quality components and taking care to assemble them properly, one can achieve high speed, precision and reliability. Construction of the printer is time-consuming. Examples of things to pay attention to during construction are that the frame is square, using threadlock on screws and proper torque, using precise 3D printed parts, and connecting all the electrical components correctly.
See also
RepRap, project to create affordable 3D printers that can print most of their own components
Prusa i3, Czech open source 3D printer
Bambu Lab, Chinese manufacturer of proprietary CoreXY printers
References
3D printers
Open hardware electronic devices
RepRap project | Voron 2.4 | [
"Engineering",
"Biology"
] | 1,211 | [
"RepRap project",
"Self-replication",
"3D printers",
"Industrial machinery"
] |
78,855,977 | https://en.wikipedia.org/wiki/Gamma%20Alpha%20Rho | Gamma Alpha Rho () was an American aeronautical engineering student honor society. It was created at the Rensselaer Polytechnic Institute in Troy, New York in 1945. It merged with Tau Omega, an aeronautical professional fraternity, to create the aeronautical honor society Sigma Gamma Tau in 1953.
History
Gamma Alpha Rho was established at the Rensselaer Polytechnic Institute in Troy, New York in 1945. Its first official meeting was held on October 21, 1945. Its founders were faculty member H. Burlage Jr. and H. L. Flomenhoft, a student of aeronautical engineering. Its founding members were Flomenhoft, Clarence Cohen, and Steve Maslem.
Gamma Alpha Rho was a social and scientific honor society, created to recognize academic, achievements, and integrity in the field of aeronautical engineering. Its founders also hoped to improve professional ethics and to create a connection between students and faculty. Its first pledge class was initiated in late 1945. Dr. John R. Weske was its first academic advisor.
In the spring of 1946, Gamma Alpha Rho's members discussed becoming a national organization. A new constitution was adopted in the fall of 1946, allowing the local group to expand. Beta chapter was chartered at Virginia Tech in 1947, followed by Gamma chapter at Purdue University. In 1948, the group officially became a "national honorary aeronautical engineering society". Membership was open to juniors and seniors studying aeronautical engineering. In June 1949, Gamma Alpha Rho initiated its first female member, Edna Van Note.
The society expanded to include seven chapters and more than 1,000 members in 1952. It merged with the professional fraternity Tau Omega to form Sigma Gamma Tau on February 28, 1953.
Symbols
The Greek letters Gamma, Alpha, and Rho were selected for the society's name because those letters are commonly used in the field of aeronautical engineering. The Gamma Alpha Rho key was shaped like a Joukowsky airfoil over a circle.
Chapters
Following is a list of Gamma Alpha Rho chapters.
Notable members
Jay R. Brill, United States Air Force Brigadier and deputy for the A-10, Aeronautical Systems Division, Air Force Systems Command at Wright-Patterson Air Force Base
Herbert A. Lyon, United States Air Force Major General in charge of the Space and Missile Test Center at Vandenberg Air Force Base
Igor Sikorsky (Alpha, 1947), aviation pioneer
References
Student societies in the United States
Engineering honor societies
Student organizations established in the 1940s
1945 establishments in New York (state)
1953 disestablishments in New York (state)
Aviation organizations based in the United States
Professional fraternities and sororities
Merged fraternities and sororities | Gamma Alpha Rho | [
"Engineering"
] | 541 | [
"Engineering societies",
"Engineering honor societies"
] |
78,856,113 | https://en.wikipedia.org/wiki/Pendeloque | A pendeloque, from French pendeloque, is a hanging often drop- or pear-shaped object or pendant used as an ornamentation, such as drop-shaped pendant earrings, and specific pear- and drop-shaped parts of chandeliers. The term is also used in describing the specific pendeloque cut for gemstone cutting.
Gallery
See also
Briolette
References
Product design | Pendeloque | [
"Engineering"
] | 85 | [
"Design stubs",
"Product design",
"Design"
] |
78,856,281 | https://en.wikipedia.org/wiki/4-Mercaptobenzoic%20acid | 4-Mercaptobenzoic acid (p-mercaptobenzoic acid, ''p''-MBA) is an organosulfur compound with the formula para-. It is used as a ligand in thiolate-protected gold cluster compounds, such as .
See also
Gold cluster
References
Benzoic acids
Thiols | 4-Mercaptobenzoic acid | [
"Chemistry"
] | 73 | [
"Organic compounds",
"Thiols"
] |
78,856,485 | https://en.wikipedia.org/wiki/Dysfunctome | The dysfunctome is a proposed conceptual framework that describes a library of circuits that may become dysfunctional in the human brain as a consequence of various brain disorders. Analogous to terms like the genome (the total genetic information of an organism), the proteome (the entire set of proteins expressed) and the connectome (the parts of the entire brain and their interconnections) the dysfunctome aims to map out how disruptions—of whichever nature—contribute to disease states and pathological signs or symptoms if specific brain circuits become dysfunctional.
Description
An increasingly adopted view is that many symptoms of neurological or psychiatric diseases originate from brain circuit dysfunctions, which have also been termed 'oscillopathies' or 'disorders of the connectome'. Indeed, evidence accumulates, that the same circuit may be responsible for the same symptom as expressed by patients with different diseases. Examples include a dysfunctional circuit between cerebellar nuclei, the cerebellar receiving thalamus and primary motor cortex, which has been associated with various forms of tremor in disorders such as Parkinson's Disease, Essential Tremor, Multiple Sclerosis and other disorders. Similarly, a common circuit involved in obsessive compulsive behavior has been identified to play a role in OCD and Tourette's Syndrome.
Finally, a shared polysynaptic brain network has been associated with the occurrence of depression in Major depression, epilepsy and Parkinson's Disease.
This transnosologic view, which associates brain circuit disruption with symptoms, rather with disorders, is also reflected by the Research Domain Criteria (RDoC) concept by the National Institutes of Mental Health.
In this light, the hypothetical concept of the dysfunctome aims at constructing an exhaustive library that maps circuits, which, when dysfunctional, will lead to a given neurological or psychiatric symptom. Critically, the concept does not specify the nature of the dysfunction, which could include hyper-/hypoactivity, loss of sensible information processing, microseizures or other disruptions that could unfold along brain circuits.
Etymology
The term “dysfunctome” combines “dysfunction,” referring to the impaired or abnormal functioning of processes, with the suffix “-ome,” commonly used to denote a totality or complete set (e.g., genome, metabolome, microbiome). The concept underscores the importance of comprehensive, system-wide approaches to understanding diseases, moving beyond the study of individual brain circuits or individual pathological symptoms.
See also
Connectome
Genome
Proteome
Systems Biology
Personalized Medicine
References
Brain anatomy
Omics
Neuroscience
Neurology
Psychiatry | Dysfunctome | [
"Biology"
] | 556 | [
"Bioinformatics",
"Neuroscience",
"Omics"
] |
78,856,659 | https://en.wikipedia.org/wiki/Cryptostictic%20acid | Cryptostictic acid is a chemical compound of the depsidone class. It has the molecular formula and is a secondary metabolite of various lichens. It was first reported in 1980 as a constituent of Lobaria oregana. It has since been identified in lichens in the genera Ramalina, Oxneriaria, and Usnea, among others.
References
Carboxylic acids
Lichen products
Heterocyclic compounds with 4 rings
Benzodioxepines
Methoxy compounds
Lactones
Triols | Cryptostictic acid | [
"Chemistry"
] | 113 | [
"Carboxylic acids",
"Natural products",
"Functional groups",
"Lichen products"
] |
78,856,733 | https://en.wikipedia.org/wiki/Fragilin | Fragilin is a chemical compound of the anthraquinone class. It has the molecular formula and is a chlorinated derivative of parietin. In 1965, it was reported as a constituent of the lichens Sphaerophorus fragilis and Sphaerophorus coralloides. It has since been found in a variety of other lichens including Nephroma laevigatum, Caloplaca, Xanthoria parietina, and others.
References
Anthraquinones
Lichen products
Chlorine-containing natural products
Diols
Methoxy compounds | Fragilin | [
"Chemistry"
] | 126 | [
"Natural products",
"Lichen products"
] |
78,856,995 | https://en.wikipedia.org/wiki/OmniGraphSketcher | OmniGraphSketcher was a software application from The Omni Group for creating quantitative diagrams. It allowed users to plot data and draw freehand curves, filled areas, and text labels on a coordinate plane. It was available from March 2009 through July 2013.
History
OmniGraphSketcher had its origins in Graph Sketcher, a Mac OS X application created by Robin Stewart that was first commercially released in 2006. The software was influenced by Stewart's academic research integrating data plotting with freehand illustration user interfaces.
The Omni Group acquired Graph Sketcher in 2008 and launched OmniGraphSketcher for Mac in March 2009, followed by an iPad version in April 2010.
In July 2013, the Omni Group discontinued OmniGraphSketcher, and in January 2014 released its source code under an open-source license as GraphSketcher.
Reception
Outlets such as Macworld, MacUser, and MacNN described OmniGraphSketcher as "one of those programs that does one thing and does it very well." Most rated it 4/5, appreciating the simplicity of making graphs but noting some limitations and interface glitches with the iPad version.
References
The Omni Group
Proprietary software for macOS
Discontinued iOS software | OmniGraphSketcher | [
"Technology"
] | 256 | [
"Computing stubs",
"Software stubs"
] |
77,388,784 | https://en.wikipedia.org/wiki/Zirconium%28II%29%20iodide | Zirconium(II) iodide is an inorganic chemical compound with the chemical formula .
Synthesis
Zirconium diiodide can be prepared from the by disproportionation at 360–390°. At higher temperatures, the diiodide disproportionates to the tetraiodide and metallic zirconium.
References
Iodides
Metal halides
Zirconium(II) compounds | Zirconium(II) iodide | [
"Chemistry"
] | 93 | [
"Inorganic compound stubs",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
77,388,818 | https://en.wikipedia.org/wiki/Zirconium%20dichloride | Zirconium dichloride is an inorganic chemical compound with the chemical formula . is a black solid. It adopts a layered structure as molybdenum disulfide
The compound can be formed by heating zirconium monochloride and zirconium tetrachloride:
Related compounds
Zirconium diiodide.
References
Chlorides
Metal halides
Zirconium(II) compounds | Zirconium dichloride | [
"Chemistry"
] | 91 | [
"Chlorides",
"Inorganic compounds",
"Inorganic compound stubs",
"Salts",
"Metal halides"
] |
77,389,197 | https://en.wikipedia.org/wiki/Adam%20Kanigowski | Adam Kanigowski (born 15 April 1989) is a Polish mathematician specializing in dynamical systems and ergodic theory. He is a professor at the University of Maryland.
Education
Kanigowski was born in Toruń. He earned his master's degree in mathematics from the Nicolaus Copernicus University in Toruń in 2012, and his Ph.D. in 2015 from the Institute of Mathematics of the Polish Academy of Sciences, under the supervision of Mariusz Lemańczyk and Joanna Kułaga-Przymus. His dissertation was entitled Własności ergodyczne gładkich potoków na powierzchniach (Ergodic properties of smooth flows on surfaces) and awarded the International Stefan Banach Prize in 2016.
Career and research
After graduating, Kanigowski joined Penn State University as an S. Chowla Research Assistant Professor in 2015 and then joined UMD as an assistant professor in 2018, where he was promoted to full professor in 2024. Since December 2022, Kanigowski has led a flagship project at Jagiellonian University that partly supports a research collaboration with UMD.
Kanigowski's research interests include dynamical systems and ergodic theory as well as their interaction with number theory, geometry and probability theory. In particular, he is interested in randomness and chaos in smooth dynamical systems, classification problems in abstract ergodic theory, and non-standard ergodic theorems that find application in number theory. Together with collaborators, he solved several longstanding open problems and conjuctures, such as the Rokhlin problem, the Sarnak hypothesis, the Katok hypothesis and the Ratner problem.
Kanigowski has published more than 30 papers in premier mathematical journals including the most prestigious ones, such as Annals of Mathematics, Journal of the American Mathematical Society, and Inventiones Mathematicae. Among his collaborators are Dmitry Dolgopyat, Bassam Fayad, Giovanni Forni, Mariusz Lemańczyk, Maksym Radziwiłł, Federico Rodriguez Hertz, and Corinna Ulcigrai.
Recognition
In 2015, the Polish Mathematical Society gave Kanigowski their Prize for Young Mathematicians (he was awarded for a series of six papers in the field of ergodic theory and operator theory). He was the 2016 winner of the International Stefan Banach Prize for a doctoral dissertation in the mathematical sciences. In 2017 he received the Kazimierz Kuratowski Award from the Institute of Mathematics of the Polish Academy of Sciences and the Polish Mathematical Society. In March 2024, the Simons Foundation named Kanigowski a 2024 Simons Fellow in Mathematics, in April he received the Institute of Mathematics of the Polish Academy of Sciences Prize for outstanding scientific achievements in mathematics for his "fundamental results in the field of dynamical systems and ergodic theory", and in July he was awarded the EMS Prize for "his outstanding contributions to the spectral classification and the mixing properties of slowly chaotic dynamical systems".
Personal life
Adam Kanigowski has two daughters. In June 2024 he finished his first Ironman triathlon.
References
1989 births
Living people
Polish mathematicians
Dynamical systems theorists
Nicolaus Copernicus University in Toruń alumni
University of Maryland, College Park faculty | Adam Kanigowski | [
"Mathematics"
] | 675 | [
"Dynamical systems theorists",
"Dynamical systems"
] |
77,389,497 | https://en.wikipedia.org/wiki/Krone%20BiG%20X | The Krone BiG X is a self-propelled forage harvester manufactured by the agricultural machinery company Krone Agriculture from Spelle. Since May 2000, this vehicle has been one of Krone's main revenue generators.
History
From May 2000, Maschinenfabrik Bernard Krone produced the first generation of the BiG X forage harvester as BiG X V8 and BiG X V12. Krone initially marketed the engine power as 540 hp. According to the German agriculture magazine Agrarheute, the concept of a forage harvester the size of the BiG X, capable of reaching speeds of 40 km/h and boasting high engine power, was new at the turn of the millennium, and the company was concerned that the true engine power might be perceived as oversized. In reality, the installed V8 engine, a Mercedes-Benz OM 502, had a power output of 605 hp. The BiG X V12 model was even more powerful, equipped with an OM 444 engine capable of up to 780 hp.
In 2007, Krone introduced the second generation with the BiG X 800, which is powered by two different engines that can be synchronized when necessary. The second generation included the BiG X 1000, BiG X 650, and from 2008, the BiG X 500. The BiG X 700, 850, and 1100 models were added in 2010. Since 2007, Krone has equipped its forage harvesters with a photo-optical sensor as standard. Integrated into the corn header, this instrument detects the maturity of the plants through color matching, preserving the structure of the harvested crop and reducing the risk of secondary fermentation.
At the 2013 Agritechnica agricultural trade fair in Hanover, Krone presentend the small BiG X series, featuring the forage harvesters BiG X 480 and 580. These new models replaced the previous BiG X 500 and distinguished themselves from their predecessor primarily due to a smaller chopping unit and overall more compact dimensions.
In the same year, Krone introduced the BiG X 600 Edition 2013 featuring a V8 engine from MAN. In 2015, Krone expanded its small range of forage harvesters with the BiG X 530 and 630 models. In September 2018, Krone unveiled its new large forage harvester series with the BiG X 680, 780, 880, and 1180 models, which replaced the old series. According to Krone, the BiG X 1180 is considered the most powerful forage harvester in the world. The vehicle reportedly has a harvesting capacity of 360 t/h according to agricultural technology magazine Profi. Apart from the engine, the BiG X 1180 is identical to the BiG X 680, 780, and 880 models. Also in 2018, for the first time, Krone introduced a roller conditioner called OptiMaxx with a diameter of 305 mm as optional equipment for the BiG X 1180.
In September 2020, Krone unveiled a new generation of the small BiG X series, including the 480, 530, 580, and 630 models, featuring a new cabin, modified crop flow, and transition to emissions stage 5. The gap between the BiG X 880 and the BiG X 1180 in the larger series was filled in September 2022 with the introduction of the BiG X 980 and the BiG X 1080. Similar to the BiG X 1180, the largest forage harvester in the series, the two new models are equipped with V12 engines from Liebherr.
Krone offers two main model ranges with the small BiG X series 480, 530, 580, and 630, as well as the large BiG X series 680, 780, 880, 980, 1080, and 1180. These ranges primarily differ in engine power and, if applicable, the diameter of the kernel processors. For the BiG X 1180, a 305 mm diameter kernel processor can be installed, unlike the other models which are shipped with a kernel processor diameter of 250 mm.
Technical description
The following technical description primarily focuses on the BiG X 1180 model, which is largely identical to the BiG X 680, 780, 880, 980, and 1080 models, differing primarily in engine specifications. Reference will also be made to the smaller models in the current series where appropriate.
Basic structure
The BiG X 1180 is a self-propelled forage harvester powered by Bosch wheel motors with an independent wheel suspension for the crop feed and a 90° machine pass-through. The crop intake of the forage harvester consists of six hydraulically driven pre-compression rollers. The knives are arranged in pairs and taper V-shaped towards the front axle. The intake can be removed from the machine for maintenance purposes. The design allows access to the chopping drum which has a diameter of 660 mm and a channel width of 800 mm. It can be equipped with universal drums (MaxFlow) with configurations of 20, 28, and 36 knives and biogas drums with configurations of 40, and 48 knives. The chopping drum bottom is curved and directs the chopped material upwards to the conditioning rollers. The conditioner OptiMaxx 250 features a 5-degree angled, diagonally positioned sawtooth profile on the 250 mm large cracking rollers, which, with an additional shearing effect, also process the chopped material in the transverse direction. The OptiMaxx 305, equipped with 305 mm large rollers, is available for the models BiG X 680 through 1180. Compared to the OptiMaxx 250, it has a 20% higher peripheral speed, an 11% larger contact area, and temperature monitoring of the bearings. The two conditioning rollers, each with a 5-degree helical tooth profile, are arranged in a counter-rotating pair and condition (or crack) the chopped material through friction. Their speed difference is 30%, 40%, or 50%. Above the conditioning rollers is the accelerator, which has an adjustable throwing distance and transports the chopped material upward through the throwing channel from the forage harvester into the discharge chute. This chute has a swivel angle of 210° and a discharge height of 6000 mm.
The BiG X 1180 is available with an automatic adjustment of the counter blade, allowing the driver to adjust it from the cab. With the camera-based 3D image analysis, the Easyload automatic loading system fills each transport vehicle alongside in parallel operation or to rear loading of the machine. Additionally, the BiG X features the Variloc system, which allows the drum speed to be adjusted in less than five minutes, enabling the forage harvester to be used for both short and long cuts. The automatic data management in the BiG X is based on Krone's Smart-Connect control unit with autologging function, which transfers the automatically recorded data to the operator's office and utilizes it for transparent billing. Alternatively, an order-based data management system is offered with an app, allowing the driver to navigate directly to the field entrance.
The BiG X series 480, 530, 580 and 630 differs from the BiG X 1180 primarily in basic structure, with a narrower channel width of 630 mm instead of 800 mm. The conditioner is technically identical to that of the larger models.
Attachments
Four different attachments are available for the BiG X directly from the factory: an EasyFlow pick-up with optional working widths of 3000 or 3800 mm; an EasyCollect row-independent harvesting attachment with optional working widths of 4500, 6000, 7500, 9000, or 10500 mm; an XCollect row-independent harvesting attachment with optional working widths of 6000, 7500, or 9000 mm; and an XDisc direct cutting attachment with a working width of 6200 mm. The XCollect differs from a conventional corn header as it does not require forced cutting. The crop is cut using sickle knives and is structurally separated from the collectors that convey the crop. According to the German agricultural technology magazine Traction, this design ensures functionality even with increased wear. The sickle disc speed can be set to either 1000 or 3000 RPM. The XCollect can be folded for road transportation.
For the BiG X series 480, 530, 580 and 630, the attachments are largely identical to those of the large series, apart from the row-independent corn harvesting attachments (EasyCollect), which are not offered with a 10500 mm working width for the small series.
Krone Nir Control dual
With the optional Krone Nir Control dual system, data on moisture and the content of harvested crops such as corn, grass, and whole plant silage are captured. This data can be recorded in the machine terminal and assigned to the harvested area. The Krone Nir Control dual system is mounted on the discharge chute of the BiG X. The Nir sensor is used both for determining content in Krone's harvesting technology and in the Zunhammer company's VanControl dual system to capture ingredients in organic fertilizers.
Drive
The forage harvester BiG X has two power paths, one mechanical and one hydraulic. All flow components (the chopping drum, conditioning rollers, and accelerator) are mechanically driven by a composite V-belt from the engine. The torque output to the pulley at the engine can be engaged and disengaged via a multi-plate clutch. The V-belt directly drives the chopping drum and accelerator via a pulley, while the conditioning rollers are driven on the opposite side by a second composite V-belt running over the accelerator. Variloc, a two-stage planetary gear is integrated into the pulley of the chopping drum, enabling a chopping drum speed of either 1250 or 800 RPM. A gearbox is flanged to the engine, to which the hydraulic pump for the propulsion drive and for driving the pre-compression rollers is flanged to.
Unlike the large BiG X, the small series forage harvesters do not require a motor output gearbox for sending power to the wheels. Engagement of all flow components is done via a belt clutch.
Chassis, tires, and cabin
As described, the harvester has hydraulic power transmission to the wheels; it features hub motors made by Bosch Rexroth, and planetary gear sets. The rear axle is a sprung double wishbone axle, which can also be equipped with hub motors upon request. There are two driving modes: a field driving mode with a range from 0 to 25 km/h and a road driving mode with a range from 0 to 40 km/h; the driving speed can be continuously adjusted. From the factory, there are five different front tire combinations and four different rear tire combinations available, with front tire widths ranging from 680 to 900 mm and rim sizes of 32, 38, or 42 inches; the 500, 620, or 710 mm wide rear tires are always mounted on 30-inch rims. All tires are radial tires. The cabin is optionally height-adjustable and can be raised by up to 700 mm.
The chassis and cabin of the small series are identical to the large BiG X. The tire options range from 680 to 900 mm with rim sizes from 32 to 42 inches.
Engines
In the BiG X, conventional industrial diesel engines from various suppliers are installed, including Daimler-Chrysler, MAN, MTU, and Liebherr.
The BiG X 980/1080/1180 is equipped with a transversely mounted Liebherr D 9512 V12 diesel engine, while the models BiG X 680/780/880 feature Liebherr D 9508 V8 diesels. With a cylinder bore of 128 mm and a piston stroke of 157 mm, this results in a displacement of 24.24 liters and 16.16 liters, respectively. The engine, with exhaust turbocharging and intercooling, has overhead valves, and does not have hydraulic tappets.
According to information from the German agricultural magazine Profi, the BiG X 1180 engine has a continuous output of 850 kW (1156 hp) at 1400 to 1800 RPM. The continuous output in XPower chopping mode is reported to be 818 kW (1112 hp), according to agricultural magazine Traction. In EcoPower mode, the power is electronically limited to 441 kW (600 hp). Maintenance intervals are set at 1000 operating hours. The harvester complies with Tier 4 final emission standards; an SCR-only strategy is used, which exclusively employs an SCR catalyst without an oxidation catalyst, exhaust gas recirculation, or diesel particulate filter. The BiG X 1180 is equipped with multiple fuel tanks, with a combined capacity of either 1100 or 1500 liters. Additionally, there is a 150-liter auxiliary tank for AdBlue and a 230-liter auxiliary tank for silage additive, with an option for an additional 275-liter silage additive tank.
Technical Specifications (As of 2018)
Sources:
Sources:
References
External links
Homepage Krone Agriculture
Krone Agriculture forage harvesters
Krone Group
Agricultural machinery
Engineering vehicles
Heavy equipment | Krone BiG X | [
"Engineering"
] | 2,648 | [
"Engineering vehicles"
] |
77,389,501 | https://en.wikipedia.org/wiki/Zirconium%20difluoride | Zirconium difluoride is an inorganic chemical compound with the chemical formula .
Synthesis
Zirconium difluoride can be prepared by the action of atomic hydrogen on thin layers of zirconium tetrafluoride, at a temperature of approximately 350°C.
Physical properties
forms black crystals of the orthorhombic system, with unit cell parameters a = 0.409 nm, b = 0.491 nm, c = 0.656 nm.
The compound readily ignites and burns to form zirconium dioxide.
Chemical properties
disproportionates when heated to 800 °C:
References
Fluorides
Metal halides
Zirconium(II) compounds | Zirconium difluoride | [
"Chemistry"
] | 146 | [
"Inorganic compounds",
"Salts",
"Inorganic compound stubs",
"Metal halides",
"Fluorides"
] |
77,389,536 | https://en.wikipedia.org/wiki/Zirconium%20trifluoride | Zirconium trifluoride is an inorganic chemical compound with the chemical formula . This is a salt of zirconium and hydrofluoric acid, forms black crystals.
Synthesis
Zirconium difluoride can be prepared by the action of atomic hydrogen on thin layers of zirconium tetrafluoride, at a temperature of approximately 350°.
Zirconium (III) fluoride can be obtained by reacting hydrogenated zirconium with a mixture of hydrogen fluoride and hydrogen at 750 °C.
It is also possible to prepare it by reducing with hydrogen at 650 °C.
Physical properties
forms black crystals of cubic system, in the space group Pm3m.
It is slightly soluble in hot water, slightly soluble in hot acids. Insoluble in caustic soda and ammonia solution. Its crystal structure corresponds to that of rhenium(VI) oxide.
Chemical properties
disproportionates to the tetrafluoride when heated to 1300 °C:
References
Fluorides
Metal halides
Zirconium(III) compounds | Zirconium trifluoride | [
"Chemistry"
] | 225 | [
"Inorganic compounds",
"Salts",
"Inorganic compound stubs",
"Metal halides",
"Fluorides"
] |
77,390,020 | https://en.wikipedia.org/wiki/Kotzig%27s%20conjecture | Kotzig's conjecture is an unproven assertion in graph theory which states that finite graphs with certain properties do not exist.
A graph is a -graph if each pair of distinct vertices is connected by exactly one path of length .
Kotzig's conjecture asserts that for there are no finite -graphs with two or more vertices.
The conjecture was first formulated by Anton Kotzig in 1974.
It has been verified for , but remains open in the general case (as of November 2024).
The conjecture is stated for because -graphs do exist for smaller values of .
-graphs are precisely the complete graphs.
The friendship theorem states that -graphs are precisely the (triangular) windmill graphs (that is, finitely many triangles joined at a common vertex; also known as friendship graphs).
History
Kotzig's conjecture was first listed as an open problem by Bondy & Murty in 1976, attributed to Kotzig and dated to 1974.
Kotzig's first own writing on the conjecture appeared in 1979.
He later verified the conjecture for and claimed solution, though unpublished, for .
The conjecture is now known to hold for due to work of Alexandr Kostochka.
Kostochka stated that his techniques extend to , but a proof of this has not been published.
A survey on -graphs was written by John A. Bondy, including proofs for many statements previously made by Kotzig without written proof.
In 1990 Xing & Hu claimed a proof of Kotzig's conjecture for .
This seemed to resolve the conjecture at the time, and still today leads many to believe that the problem is settled.
However, Xing and Hu's proof relied on a misunderstanding of a statement proven by Kotzig. Kotzig showed that a -graph must contain a -cycle for some , which Xing and Hu used in the form that cycles of all these lengths must exist.
In their paper Xing and Hu show that for a -graph must not contain a -cycle.
Since this is in contradiction to their reading of Kotzig's result, they conclude (incorrectly) that -graphs with cannot exist.
This mistake was first pointed out by Roland Häggkvist in 2000.
Kotzig's conjecture is mentioned in Proofs from THE BOOK in the chapter on the friendship theorem.
It is stated that a general proof for the conjecture seems "out of reach".
Properties of -graphs
A -graph on vertices contains precisely paths of length .
Since the two end-vertices of an edge in a -graph are connected by a unique -path, each edge is contained in a unique -cycle. Consequently, the graph has a unique decomposition into edge disjoint -cycles, and there are no other -cycles besides these. In particular, -graphs are Eulerian.
-graphs are not bipartite: if is odd and are vertices in the same bipartition class, no -path can connect them. Likewise, if is even and are vertices in different bipartition classes, no -path can connect them.
Even cycles form important substructures in -graphs. A lollipop (sometimes also monocle) is the union of an even -cycle with a path that intersects the cycles in precisely one of its end vertices. The path must be shorter than as it would otherwise give rise to two -paths with the same end vertices. Therefore, the existence and distribution of lollipops, and more generally, of even cycles, has been studied extensively. It is known that there must exist an even cycle of length for some , and that there cannot exist even cycles of lengths , , , , or .
A -graph cannot contain a cycle (even or odd) of length at least . At the same time, there must exist a cycle of length at least . Combining these constraints yield .
Any two -cycles in a -graph must have at least three and at most vertices in common. In particular, is 2-connected. Kotzig furthermore claims that any two -cycles have at least seven vertices in common, though no proof has been published.
Let denote the number of -cycles in a given -graph. Then . If is even, then . If is odd, then . Consequently, the number of edges in a -graph (for odd) is bounded, and since -graphs are connected, so is the number of vertices.
References
Graph theory
Unsolved problems in mathematics | Kotzig's conjecture | [
"Mathematics"
] | 915 | [
"Unsolved problems in mathematics",
"Mathematical problems",
"Unsolved problems in graph theory"
] |
77,390,149 | https://en.wikipedia.org/wiki/Balanced%20group | In group theory, a balanced group is a topological group whose left and right uniform structres coincide.
Definition
A topological group is said to be balanced if it satisfies the following equivalent conditions.
The identity element has a local base consisting of neighborhoods invariant under conjugation (i.e., ones for which for all ).
The right uniform structure and the left uniform structure of are the same.
The group multiplication is uniformly continuous, with respect to the right uniform structure of .
The group multiplication is uniformly continuous, with respect to the left uniform structure of .
Properties
The completion of a balanced group with respect to its uniform structure admits a unique topological group structure extending that of . This generalizes the case of abelian groups and is a special case of the two-sided completion of an arbitrary topological group, which is with respect to the coarsest uniform structure finer than both the left and the right uniform structures.
For a unimodular group (i.e., a Hausdorff locally compact group whose left and right Haar measures coincide) , the following two conditions are equivalent.
is balanced.
In the left von Neumann algebra of , every element having a left inverse has a right inverse.
Examples
Trivially every Abelian topological group is balanced. Every compact topological group (not necessarily Hausdorff) is balanced, which follows from the Heine–Cantor theorem for uniform spaces. Neither of these two sufficient conditions is necessary, for there are non-Abelian compact groups (such as the orthogonal group ) and there are non-compact abelian groups (such as ).
References
Topological groups | Balanced group | [
"Mathematics"
] | 326 | [
"Topological spaces",
"Space (mathematics)",
"Topological groups"
] |
77,390,810 | https://en.wikipedia.org/wiki/Technetium%28III%29%20bromide | Technetium tribromide is a binary inorganic chemical compound of technetium metal and bromine with the chemical formula .
Synthesis
can be synthesized by reaction of Tc metal with elemental bromine at 400 °C.
Physical properties
crystallizes in the orthorhombic space group Pmmn (a = 11.0656(2) Å, b = 5.9717(1) Å, c = 6.3870(1) Å.
Technetium tribromide is isomorphous with and .
The compound is stable in air for weeks and insoluble in common organic solvents.
References
Technetium compounds
Bromides
Metal halides | Technetium(III) bromide | [
"Chemistry"
] | 139 | [
"Bromides",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
77,391,228 | https://en.wikipedia.org/wiki/Xooduovirus | Xooduovirus is a genus of double-stranded DNA viruses in the family Mesyanzhinovviridae. It was named for the type species Xanthomonas phage Xoo-sp2, which is now called Xooduovirus Xoosp2. That species is a lytic bacteriophage that affects Xanthomonas oryzae pv. oryzae.
References
Further reading
Virus genera
Bacteriophages
Caudovirales | Xooduovirus | [
"Biology"
] | 103 | [
"Virus stubs",
"Viruses"
] |
77,391,914 | https://en.wikipedia.org/wiki/Hering%27s%20Paradox | Hering's paradox describes a physical experiment in the field of electromagnetism that seems to contradict Maxwell's equation in general, and Faraday's Law of Induction and the flux rule in particular. In his study on the subject, Carl Hering concluded in 1908 that the usual statement of Faraday's Law (at the turn of the century) was imperfect and that it required to be modified in order to become universal.
Since then, Hering's paradox has been used repeatedly in physics didactics to demonstrate the application of Faraday's Law of Induction, and it can be considered to be completely understood within the theory of classical electrodynamics. Grabinski criticizes, however, that most of the presentations in introductory textbooks were problematical. Either, Faraday's Law was misinterpreted in a way that leads to confusion, or solely such frames of reference were chosen that avoid the need of an explanation. In the following, Hering's paradox is first shown experimentally in a video and -- in a similar way as suggested by Grabinski -- it is shown, that when carefully treated with full mathematical consistency, the experiment does not contradict Faraday's Law of Induction. Finally, the typical pitfalls of applying Faraday's Law are mentioned.
Experiment
The experiment is shown in the video on the right side. In the experiment, a slotted iron core is used, where a coil fed with a direct current generates a constant magnetic field in the core and in its slot.
Two different experiments are carried out in parallel:
*In the lower part, an ordinary conductor loop is passed through the slot of the iron core. As there is a magnetic field in this slot, a voltage is generated at the ends of the conductor loop, which is amplified and displayed in the lower oscilloscope image.
*A modified conductor loop is realized in the upper part. The conductor loop is split at one point and the split ends are fitted with a metal wheel. During the experiment, the metal wheels move around the magnetic core and exert a certain contact pressure on each other and on the core, respectively. As the magnetic core is electrically conductive, there is always an electrical connection between the wheels and therefore between the separated ends of the loop. The oscilloscope does not show any voltage despite the otherwise identical conditions as in the first experiment.
In both experiments, the same change in magnetic flux occurs at the same time. However, the oscilloscope only shows a voltage in one experiment, although one would expect the same induced voltage to be present in both experiments. This unexpected result is called Hering's paradox, named after Carl Hering.
Explanation
Moving wires/oscilloscope, magnet at rest
The easiest way to understand the outcome of the experiment is to view it from the rest frame of the magnet, i. e. the magnet is at rest, and the oscilloscope and the wires are at motion. In this frame of reference, there is no reason for a voltage to arise, because the set-up consists of a magnet at rest and some wires moving in a field free space around the magnet, which scratch the magnet a little.
To conclude, there is
* no change of the magnetic field anywhere () and thus no current-driving force on the charges in the circuit due to rest induction,
* and those parts of the circuit having charges being at motion () are not exposed to a magnetic field () and vice versa, so that there is no magnetic force on the charges anywhere in the circuit.
Moving magnet, wires/oscilloscope at rest
While the perspective from the rest frame of the magnet causes no difficulties in understanding, this is not the case when viewed from a frame of reference in which the oscilloscope and the cables are at rest and an electrically conductive permanent magnet moves into a conductor loop at a speed of . Under these circumstances, there is rest induction due to the movement of the magnet ( at the front edge of the magnet), and beyond that, the magnet is also a moving conductor. The double function of the magnet as a conductor at motion on the one hand, and as the root cause for the magnetic field on the other hand raises an essential question: Does the magnetic field of the magnet exert a Lorentz force on the charges inside the magnet? The correct answer to this question is "Yes, it does", and it is one of the pitfalls concerning the application of Faraday's Law. For some people it is contraintuitive to assume that a Lorentz force is exerted to a charge although there is no relative motion between the magnet and the charge.
An essential step of solving the paradox is the realization that the inside of the conductive moving magnet is not field-free, but that a non-zero electric field strength prevails there. If this field strength is integrated along the line , the result is the desired induced voltage. However, the induced voltage is not localized in the oscilloscope, but in the magnet.
The equation can be derived from the consideration that there is obviously no current-driving force acting on any section of the circuit. Since the absence of forces also applies in particular to the inside of the magnet, the total electromagnetic force for a charge located inside the magnet equals . If we assume that the charge moves “slip-free” with the magnet (), the following also applies: . The last equation, however, is mathematically equivalent to .
Finally, the following electric field strengths result for the various sections of the conductor loop:
To check whether the outcome of the experiment is compatible with Maxwell's equations, we first write down the Maxwell Faraday equation in integral notation:
Here is the induction surface, and is its boundary curve, which is assumed to be composed of the (stationary) sections , , and , respectively. The dot indicates the dot product between two vectors. The direction of integration (clockwise) and the surface orientation (pointing into the screen) are right-handed to each other as assumed in the Maxwell Faraday equation.
Considering the electrical field strengths shown in the table, the left side of the Maxwell Faraday equation can be written as:
The minus sign is due to the fact that the direction of integration is opposite to the direction of the electric field strength ().
To calculate the right-hand side of the equation, we state that within the time the magnetic field of the induction surface increases from to () within a strip of length and width ().
Thus the right side of the equation equals
The right and left sides of the equation are obviously identical. This shows that Hering's paradox is in perfect agreement with the Maxwell Faraday equation.
Note that the speed of the boundary curve has no physical importance whatsoever. This can be seen most easily in the differential notation of the Maxwell-Faraday equation where neither the induction area nor its boundary occurs. From a mathematical point of view, the boundary curve is just an imaginary line that had to be introduced to convert the Maxwell-Faraday equation to its integral notation such as to establish a relationship to electical voltages.
Because the boundary curve is physically of no importance, the outcome of an experiment does not depends on the speed of this curve and it is not affected by whether or not the speed of the boundary curve corresponds to the speed of a conductor wire being located at the same place. For reasons of simplicity, the speed of the boundary curve is assumed to be zero in this article.
The movement that actually counts is the movement of the (electrically conducting) magnet. It affects the value of the electric field strength inside the magnet and is thus accounted for in the Maxwell-Faraday equation via the numerical value of the vector field .
Pitfalls
The difficulties in understanding Hering's paradox and similar problems are usually based on three misunderstandings:
(1) the lack of distinction between the velocity of the boundary curve and the velocity of a conductor present at the location of the boundary curve,
(2) the uncertainty as to whether the term in the Maxwell-Faraday equation is just an imaginary boundary line or a conductor (correct is: is a boundary curve without any physical properties) and
(3) ignoring the fact that in an ideal conductor moving in a magnetic field with flux density , there is a non-zero electric field strength .
If these points are consistently considered, Hering's paradox turns out to be in perfect agreement to Faraday's law of induction (given by the Maxwell Faraday equation) viewed from any frame of reference whatsoever. Furthermore, the difficulties in understanding the (thought) experiments described in the chapter "Exceptions to the flow rule" in the "Feynman Lectures" are due to the same misunderstandings.
References
Faraday's law of electromagnetic induction
Michael Faraday
Maxwell's equations
de:Heringsches Paradoxon | Hering's Paradox | [
"Physics",
"Mathematics"
] | 1,808 | [
"Electrodynamics",
"Maxwell's equations",
"Equations of physics",
"Dynamical systems"
] |
77,393,836 | https://en.wikipedia.org/wiki/NGC%201585 | NGC 1585 is a spiral galaxy in the constellation of Caelum. Its velocity with respect to the cosmic microwave background is 4,635 ± 31km/s, which corresponds to a Hubble distance of 68.4 ± 4.8Mpc (∼223million light-years). It was discovered by British astronomer John Herschel on 1 December 1837.
The SIMBAD database lists NGC1585 as a Seyfert I Galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.
One supernova has been observed in NGC1585: SN2023vio (type Iax [02cx-like], mag.19.053) was discovered by ATLAS on 17 October 2023.
See also
List of NGC objects (1001–2000)
References
External links
1585
015150
04259-4216
Caelum
18371201
Discoveries by John Herschel
-07-10-006
Unbarred spiral galaxies | NGC 1585 | [
"Astronomy"
] | 231 | [
"Caelum",
"Constellations"
] |
77,393,972 | https://en.wikipedia.org/wiki/NGC%201320 | NGC 1320 is a spiral galaxy located in the constellation Eridanus. Its speed relative to the cosmic microwave background is 2,620 ± 15 km/s, which corresponds to a Hubble distance of 38.6 ± 2.7 Mpc (∼126 million ly). It was discovered by the German-British astronomer William Herschel in 1784.
The luminosity class of NGC 1320 is I and it is an active Seyfert 2 galaxy. NGC 1320 is a galaxy whose core shines in the ultraviolet region. It is listed in the Markarian catalog under the symbol Mrk 607 (MK 607).
To date, a non-redshift-based measurement gives a distance of approximately 37,700 Mpc (∼123 million ly). This value is within the Hubble distance values.
Supermassive black hole
According to the authors of a paper published in 2002, the mass of the central black hole of NGC 1230 is 1.51 x 107 𝑀⊙. A study carried out in 2007 on 90 Seyfert 2 type galaxies using velocity dispersion made it possible to estimate the mass of their central supermassive black holes. For NGC 1320, the mass of the black hole is 15 ×106 𝑀⊙.
According to another study published in 2012 and based on the dispersion of the velocities of the central region of NGC 3982, the mass of the central black hole would be 19.5 million 𝑀⊙.
Supernova
One supernova has been observed in NGC 1320: SN1994aa (typeIa, mag. 17) was discovered by the Scottish-Australian astronomer Robert H. McNaught on 11 September 1994.
See also
List of spiral galaxies
List of NGC objects (1001–2000)
External links
NGC 1320 at NASA/IPAC
NGC 1320 at SIMBAD
NGC 1320 at LEDA
References
Unbarred spiral galaxies
Seyfert galaxies
Eridanus (constellation)
Astronomical objects discovered in 1784
Discoveries by William Herschel
1320
Markarian galaxies
12756 | NGC 1320 | [
"Astronomy"
] | 424 | [
"Eridanus (constellation)",
"Constellations"
] |
77,393,973 | https://en.wikipedia.org/wiki/NGC%201340 | NGC 1340 is an elliptical galaxy located in the constellation Fornax. Its speed relative to the cosmic microwave background is 1,126 ± 17 km/s, which corresponds to a Hubble Distance of 16.6 ± 1.2 Mpc (∼54.1 million ly). It was discovered by the German-British astronomer William Herschel in 1790, but it was added to the New General Catalog under the designation NGC 1344 later.
This galaxy was later observed by the British astronomer John Herschel on November 19, 1835, and it is this observation that was added to the New General Catalog under the designation NGC 1340.
To date, 34 non-redshift measurements yield a distance of 18.688 ± 3.160 Mpc (∼61 million ly), which is within the Hubble distance range.
NGC 1399 group
NGC 1340 (NGC 1344 in Garcia's article) is part of the NGC 1399 group. This group is part of the Fornax cluster and it includes at least 42 galaxies, including NGC 1326, NGC 1336, NGC 1339, NGC 1351, NGC 1366, NGC 1369, NGC 1373, NGC 1374, NGC 1379, NGC 1387, NGC 1399, NGC 1406, NGC 1419, NGC 1425, NGC 1427, NGC 1428, NGC 1436 (NGC 1437), NGC 1460, IC 1913 and IC 1919.
See also
List of NGC objects (1001–2000)
External links
NGC 1340 at NASA/IPAC
NGC 1340 at SIMBAD
NGC 1340 at LEDA
References
Elliptical galaxies
Fornax Cluster
Fornax
Astronomical objects discovered in 1790
Discoveries by William Herschel
1340
12923
ESO objects
-05-09-005 | NGC 1340 | [
"Astronomy"
] | 367 | [
"Fornax",
"Constellations"
] |
77,394,414 | https://en.wikipedia.org/wiki/Skin%20lightening%20in%20the%20Middle%20East | Skin lightening is a common practice in several Middle Eastern countries, particularly among women. The use of skin lightening products among Middle Eastern women has been attributed to the perceived association between light skin and beauty, as well as marriage and employment opportunities. Furthermore, the portrayal of light skin as the beauty ideal in popular media has contributed to the use of skin lightening products among Middle Eastern women.
History
Palestinian scholar Sonia Nimr has stated that the preference for lighter skin can be found in old Arabic and pre-Islamic poetry, stating: For centuries there’s been an image that if you’re pale or whiter, it means you’re a lady. You don’t have to go out of the tent to do hard work.
By country
Jordan
In a 2010 study conducted among 318 Jordanian women at selected pharmacy stores, 60.7% of the women reported using skin lightening products at some point in their lives.
Palestine
In 2009, a correspondent from The Christian Science Monitor investigated the use of skin lightening products among women in the city of Ramallah, by interviewing users of skin lightening products, as well as businesses which sold these products.
When interviewed, an employee at a beauty salon expressed the following sentiment:Palestinians believe that white skin is beautiful. In the West, they sunbathe to get darker skin, but here, people like to lighten their skin and they hide from the sun at all costs.A 2023 study found that Palestinian women from urban areas and those with a bachelor's degree were more likely to use skin lightening products.
Saudi Arabia
Skin lightening is prevalent among Saudi women, as indicated by several studies.
A 2019 study conducted among 760 Saudi female students found that 56.2% of the participants had used skin lightening products at some point in their lives. Women with lower socioeconomic status were more likely to use skin lightening products.
In another 2019 study, 605 Saudi women were asked about their use of skin lightening products. 63.1% of the participants reported using skin lightening products at some point in their lives.
Media
The portrayal of light skin as the beauty ideal in Middle Eastern popular media has contributed to the use of skin lightening products among Middle Eastern women. An investigation by a correspondent from The Christian Science Monitor conducted in the Palestinian city of Ramallah found that Lebanese singers with European features, including Haifa Wehbe and Nancy Ajram are widely considered beauty icons. Furthermore, Sudanese-born writer Nesrine Malik stated Lebanese standards of beauty and complexion have taken the Arab world by storm since the resurgence of the Lebanese in media ... further limiting the accepted definition of beauty as light-skinned, catty-eyed and slim-nosed.
See also
Human skin color
Colorism
References
Physical attractiveness
Human skin color
Skin whitening | Skin lightening in the Middle East | [
"Biology"
] | 565 | [
"Human skin color",
"Pigmentation"
] |
77,395,139 | https://en.wikipedia.org/wiki/Emily%20Bugeja | Emily Claire Bugeja (born 30 April 1999) is a Canadian kitefoiler who was sixth in the Pan American Games in 2023. She was nominated to compete for Canada at the 2024 Olympics.
Life
Bugeja was born in North Vancouver in 1999. By the age of eight she was beginning her commitment to sailing on an Optimist dinghy. In 2016 she went to New Zealand to sail at the 2016 Youth Worlds. In 2017 she was competing in the 29er class dinghy at the 2017 Canada Games where she won a bronze medal.
Bugeja took up Formula Kite and three years later she was in Santiago in 2023 when she came sixth in the Pan American Games that was held in Chile. She was also the highest placed Canadian at the Trofeo Princesa Sofia regatta. This result meant that Canada had a reserved place for Formula Kite at the 2024 Olympics. Only one athlete is allowed from any one country and Canada's place went to Bugeja as she had scored slightly more highly that her rival kite foiler Marie-Ève Mayrand.
She studied Electrical Engineering in Ontario at Queen's University at Kingston where her interest was in robotics.
The places to join the first Olympic Formula Foil competition at the 2024 Olympics were highly valued. The "last chance" contest (French Olympic Week) was held in Hyères in April 2024 when the last five Olympic places were the prizes for kitefoilers. By this time the chosen competitors representing different continents included not only Bugeja, but Justina Kitchen from New Zealand, Fawn Jantawan from Thailand, Catalina Turienzo from Argentina, Julie Paturau from Mauritius and the Spaniard Gisela Pulido. She was 40th in the overall standings at the 2024 Formula Kite World Championships at Hyères in May 2024. She was chosen to be Canada's athlete joining five others identified for Canada's sailing team over Nataliya Leshko and Martyna Dakowicz. In June 2024, Bugeja was named to Canada's 2024 Olympic team.
References
1999 births
Living people
People from North Vancouver
Canadian female sailors (sport)
Electrical engineers
Queen's University at Kingston alumni
29er class sailors
Olympic sailors for Canada
Sailors at the 2024 Summer Olympics
21st-century Canadian sportswomen | Emily Bugeja | [
"Engineering"
] | 472 | [
"Electrical engineering",
"Electrical engineers"
] |
77,395,174 | https://en.wikipedia.org/wiki/Pellet%20%28steel%20industry%29 | Pellets are a processed form of iron ore utilized in the steel industry, specifically designed for direct application in blast furnaces or direct reduction plants. These pellets are spherical in shape, with diameters ranging from 8 to 18 millimeters.
The production of iron ore pellets involves several steps, including grinding the ore, mixing it with binders, and then forming and heating the pellets. The iron content of the pellets generally ranges from 62% to 66%. This enrichment process improves the iron concentration and imparts specific chemical and mechanical properties that enhance the efficiency of steel production.
History
The pelletizing of powdered iron ores was first introduced at the end of the nineteenth century, utilizing tar as a binding agent, comprising 1% by weight. This method involved firing the mixture in a rotating drum to create pellets suitable for blast furnaces, while also facilitating the removal of undesirable elements such as sulfur and arsenic through the emitted fumes.
During this period, pellet sintering developed alongside grate sintering as an alternative process to address the agglomeration challenges faced by high-quality iron ore products. The concept of pellet agglomeration was initially patented by A. Anderson in Sweden in 1912, followed by a similar patent in Germany in 1913. The resultant product was named "GEROELL", derived from the German word for "rolling." Pellets produced through this method demonstrated faster reduction rates compared to calibrated ores and agglomerates made from the same feedstock. In 1926, an industrial pilot plant was constructed by Krupp in Rheinhausen to explore the potential of this pelletizing technology. However, the plant was later dismantled to make way for the installation of a large-scale grate sintering line, which emerged as a competing process in the industry.
Pellet sintering has remained a viable method for processing iron ore. In the United States, this technique was employed to process fine concentrates from the Mesabi Range during World War II. This was necessary as naturally rich iron ores (containing over 50% iron) were being depleted. The development of pelletizing fine magnetite ores, which typically have less than 44 mm in size and are around 85% iron, began around 1943 with support from the University of Minnesota. The process was later adopted in Europe, particularly in Sweden, to facilitate the production of pre-reduced iron ore.
Pellet production saw substantial growth between 1960 and 1980 but eventually plateaued at approximately 300 million tons annually. The following data illustrates pellet production over several years:
In 1984, global pellet production reached 189 million tons, with North America producing 90 million tons, the USSR 63 million tons, and other regions 36 million tons.
By 1992, production had increased to 264 million tons.
In 2008, production further rose to 313 million tons.
However, in 2009, production decreased to 215 million tons due to the economic crisis.
In 2010, production rebounded to 388 million tons.
Production
Pellets are produced directly at the extraction site by mining companies and are marketed as a distinct product, unlike agglomerates which are typically manufactured at blast furnace sites through the mixing of iron ores from various sources. Pellets are generally more robust and better suited to handling compared to agglomerates, which are relatively fragile. The production process for pellets can vary significantly depending on the local characteristics of the iron ore, and some facilities may include additional stages, such as arsenic removal. The pellet production process involves several key stages:
Crushing: The iron ore is first finely crushed to separate the valuable iron ore from non-valuable gangue materials.
Enrichment: Depending on the ore's characteristics, enrichment is achieved through grinding (which can be conducted in multiple phases and may use either dry or wet methods) and by employing magnetic separation and flotation techniques.
Blending: The ore concentrate may be mixed with additives to achieve the desired chemical composition. Common additives include dolomite, olivine, and quartzite, which typically account for 3 to 3.5% of the pellet's weight.
Binding: To ensure cohesion during the pelletizing process, an additional binder, usually wet bentonite combined with maize flour or polyacrylamide, is added.
These processes ensure that the pellets are produced to meet specific quality standards and can withstand the demands of handling and transportation.
The ore concentrate is formed into pellets through a compaction process. This can be performed using various types of mixing equipment, though saucers are the most commonly employed tool. Before being subjected to sintering, the pellets are referred to as "green" or "raw" pellets, and their typical diameter ranges from 5 to 20 mm.
Following pellet formation, they are either sent to a consumption plant or directed to a cooking oven. Due to their inherent fragility, which persists despite the binder used, pellets are generally more suitable for processing in a cooking oven rather than a consumption plant. After cooking, the pellets are cooled.
The cooking process involves passing the pellets through a chain of contiguous ovens, where they are heated to temperatures of up to 1,200°C. This can be achieved using different methods: a straight grate process for a single, uninterrupted chain or a grate kiln process that includes a rotating cooling tray at the end of the chain. The required heat for this process is supplied by burners, which can either add fuel to the ore concentrate or facilitate the oxidation of the ore, depending on the specific type of ore being processed.
Benefits and limitations
Benefits
Pelletizing ore enhances the efficiency of blast furnaces and direct reduction plants by providing several advantages over raw iron ore:
Handling Resistance: Pellets are more resilient to handling, including in wet conditions, and do not cause clogging in storage hoppers.
Uniform Composition: The consistent and known composition of pellets facilitates a more streamlined process for converting them into iron.
Optimal Porosity: The porosity of pellets enables effective gas-solid chemical reactions within the furnace. This porosity helps maintain the material’s mechanical strength and chemical reactivity, even in the furnace’s highest temperature zones.
Efficient Reduction: The controlled oxidation state of iron oxides in pellets allows carbon monoxide to more effectively reduce Fe2O3 compared to less oxidized compounds like Fe3O4.
Pellets generally contain a higher iron content than agglomerated ore, leading to increased plant productivity and reduced fuel consumption. They are also more durable and capable of withstanding repeated handling. Despite their higher cost—typically about 70% more than raw ore—the benefits they offer in terms of efficiency and performance justify the expense. In steelmaking, pellets are often mixed with sinter in varying proportions to optimize the process.
Similar to sinter, the high-temperature roasting and sintering of pellets effectively eliminate undesirable elements such as sulfur. It is also an efficient method for removing zinc, which can otherwise hinder the operation of blast furnaces. With a vaporization temperature of 907°C, zinc is effectively removed during the roasting process, making pelletizing a suitable method for this application.
Limitations
Pellets are vulnerable to sulfur-induced damage during the reduction process in blast furnaces. Even low levels of sulfur dioxide (SO₂) can interfere with furnace operations, with effects observed at concentrations as low as 5 to 50 parts per million (ppm) in the reduction gas. The detailed mechanism behind this issue was only fully understood towards the end of the 20th century. Initially, sulfur accelerates the extraction of oxygen from the iron oxide, but this effect reverses once metallic iron begins to form, significantly slowing the oxygen extraction process. This unusual behavior is attributed to sulfur's strong affinity for the metallic iron that forms on the pellet surface, which inhibits the penetration of carbon.
Furthermore, the reaction between wustite (FeO) and carbon monoxide (CO) occurs not only on the surface of FeO but also beneath the surface of the reduced iron. Due to iron's superior absorption characteristics, a substantial portion of gas transport happens at the iron/iron oxide phase boundary. This process depends on the iron's ability to absorb sufficient carbon (carburization). If sulfur obstructs carbon absorption, reduction is limited to the surface of the iron oxide. This restriction results in the formation of elongated, fibrous iron crystals, as iron crystallization can only proceed in the direction of the reducing iron oxide. Consequently, the structure of the granules becomes reinforced and can expand to two or three times their original volume. This expansion, or "swelling," of the granules can lead to blockage or significant damage to the blast furnace, highlighting the challenges associated with using pellets in blast furnace operations.
Composition
Pellets, similar to agglomerates, are classified based on their chemical properties as either acidic or basic. To determine the basicity index (ic), the following ratio of mass concentrations is used:
This ratio helps in assessing the relative basicity of the pellets, which is important for optimizing their use in blast furnaces and other metallurgical processes.
In practice, a simplified basicity index (i) is commonly used to classify pellets based on their chemical properties. This index is calculated using the ratio of calcium oxide (CaO) to silicon dioxide (SiO2):
i=\frac{CaO}{SiO2}
Pellets with an index (i) less than 1 are classified as acidic.
Pellets with an index (i) greater than 1 are categorized as basic.
Pellets with an index (i) equal to 1 are referred to as self-melting.
Pellets can contain high levels of hematite, but the proportion must be controlled. Excessive hematite can weaken the pellet structure during reduction, leading to the pellets breaking down into dust under the weight of stacked charges. This is due to the fact that a high hematite content can cause the pellets to disintegrate, compromising their integrity and usability in the reduction process.
Acid pellets
Acid pellets are produced without the addition of additives, resulting in a specific chemical composition. Typically, the composition of acid pellets is as follows: 2.2% SiO2 and 0.2% CaO. In the United States during the 1990s, the typical characteristics of acid pellets were:
Chemical Composition: 66% Fe, 4.8% SiO2, 0.2% MgO, and a CaO/SiO2 ratio of 0.04.
Compressive Strength: 250 kg.
ISO Reducibility: 1.0.
Swelling Ratio: 16%.
Softening Temperature: 1290°C, with a difference of 230°C between the softening and melting temperatures.
Unlike agglomerated ores, which may include basic fluxes like silicates in the binder during pelletizing, acid pellets maintain their acidic composition due to their solid spherical shape. This design helps preserve their mechanical properties and reduces the risk of disintegration.
Acid pellets exhibit notable mechanical strength with a crush resistance exceeding 250 kg per pellet. However, their reducibility could be improved. Additionally, they are prone to swelling when exposed to lime, especially when the basicity index (i = CaO / SiO2) exceeds 0.25, which may potentially cause issues in a blast furnace.
Self-melting pellets
Self-melting pellets, also known as basic pellets, are a type of iron ore pellet that was developed in the United States in the 1990s. These pellets are designed for use in blast furnaces and are produced by adding lime (calcium oxide) and magnesia (magnesium oxide) to iron ore concentrate, enhancing their metallurgical properties. Self-melting pellets typically have the following properties:
Iron (Fe) content: 63%
Silicon dioxide (SiO2) content: 4.2%
Magnesium oxide (MgO) content: 1.6%
Calcium oxide to silicon dioxide ratio (CaO/SiO2): 1.10
Compressive strength: 240 kg per pellet
ISO reducibility: 1.2
Expansion ratio: 15%
Softening temperature: 1,440°C, with a difference of 80°C between the softening and melting temperatures
These pellets are recognized for their high compressive strength and ease of reduction, making them well-suited for blast furnace operations. The production process of self-melting pellets involves incorporating limestone into the iron ore concentrate. This inclusion affects the productivity of pellet plants due to the calcination process, which involves the endothermic process of limestone. As a result, the overall productivity of the pellet plant can decrease by approximately 10 to 15% compared to the production of acid pellets, which do not include lime. Self-melting pellets are appreciated for their enhanced performance in blast furnaces but require consideration of the trade-offs in production efficiency.
Pellets with low silica content
These pellets are designed for use in direct reduction plants. The typical composition of the pellets includes: 67.8% iron (Fe), 1.7% silicon dioxide (SiO2 ), 0.40% aluminum oxide (Al2O3), 0.50% calcium oxide (CaO), 0.30% magnesium oxide (MgO), and 0.01% phosphorus (P).
Low-silica pellets, when doped with lime, can self-fuse. A typical composition for these self-fusing pellets is: 65.1% iron (Fe), 2.5% silicon dioxide (SiO2), 0.45% aluminum oxide (Al2O3 ), 2.25% calcium oxide (CaO), 1.50% magnesium oxide (MgO), and 0.01% phosphorus (P).
Other types of pellets
To cater to specific customer needs, manufacturers have developed alternative pellet types that offer distinct properties and performance characteristics:
Self-Reducing Pellets: Self-reducing pellets are composed of iron ore and coal, which serve as an internal reducing agent during smelting. This design allows the pellets to undergo reduction without the need for additional reducing materials, enhancing efficiency in certain metallurgical processes.
Magnesian Pellets: Magnesian pellets are created by adding minerals such as olivine or serpentine, which increase the magnesia (MgO) content to approximately 1.5%. These pellets are characterized by their balanced performance in blast furnaces, with an average cold crush resistance of around 180 kg per pellet. The added magnesia helps improve the metallurgical properties of the pellets, making them suitable for specific reduction conditions.
These alternative pellet types are designed to address different operational requirements and enhance the flexibility of iron-making processes.
Notes
References
Bibliography
Related articles
Agglomerate (steel industry)
Metallurgy
Minerals
Steel industry | Pellet (steel industry) | [
"Chemistry",
"Materials_science",
"Engineering"
] | 3,151 | [
"Metallurgy",
"Materials science",
"nan"
] |
77,395,673 | https://en.wikipedia.org/wiki/Zirconium%20dibromide | Zirconium dibromide is an inorganic chemical compound with the chemical formula .
Synthesis
The compound can be prepared by reacting both elements:
Also, there is a method for obtaining zirconium dibromide by thermal disproportionation of ZrBr at 550 °C.
References
Bromides
Metal halides
Zirconium(II) compounds | Zirconium dibromide | [
"Chemistry"
] | 76 | [
"Inorganic compounds",
"Salts",
"Inorganic compound stubs",
"Bromides",
"Metal halides"
] |
77,396,324 | https://en.wikipedia.org/wiki/Georg%20Thomas%20Sabler | Georg Thomas Sabler (Russian: Его́р Его́рович Са́блер or Георг Заблер, Lithuanian: Georgas Tomas Sableris; – 7 December 1865) was an astronomer and geodesist of Baltic German origin active in territories of modern-day Estonia, Lithuania, Ukraine, and Russia (then all part of the Russian Empire).
A student of Friedrich Georg Wilhelm von Struve, Sabler studied theology and mathematics at the University of Tartu. Fascinated by Struve's lectures of astronomy, Sabler participated in an expedition that measured the difference of sea levels in the Black Sea and Caspian Sea. Sabler then worked as an astronomer at Tartu Observatory and Pulkovo Observatory, and later became the director of the Vilnius University Astronomical Observatory, which received its own photoheliograph due to Sabler's efforts. The telescope was the second one produced in the world. Sabler and his assistant Matvey Gusev pioneered the photography and research of sunspots.
He was described as the "creator and pioneer of new astrophysical research at the Vilnius observatory". Sabler also constructed a star catalog, took care of the methodology of observations, and constructed various astronomical instruments such as achromatic lenses. Notably, Sabler participated in determining the Struve Geodetic Arc in Finland, Lithuania, Ukraine, and Bessarabia. Sabler was the first to find a way to determine the angle of refraction in transparent media.
Biography
Early life and studies
Georg Thomas Sabler was born on in Haljala, now part of Lääne-Viru County, Estonia. His father, Georg Christian Sabler (1776–1819), was a Lutheran pastor. At first, Sabler studied privately. Later, Sabler graduated from the Tartu Evangelical Cathedral's gymnasium. Sabler studied theology (1828–1832) and mathematics (1832–1839) at the University of Tartu. He developed an interest in natural sciences, especially in astronomy, which was lectured by Friedrich Georg Wilhelm von Struve. During his study years, Sabler was engaged in astronomical observations, particularly of binary stars. Some of his works were published in the scientific press. For his scientific aptitude, von Struve ensured that Sabler began working at the Tartu Observatory as an assistant to its director until 1839.
In 1836–1837 Sabler participated in an expedition that determined the difference between the sea levels of the Black Sea and Caspian Sea. He also edited the material collected during the expedition and published it in German under the title "Beschreibung der zur Ermittelung des Höhenunterschiedes zwischen dem Schwarzen und dem Caspischen Meere... in den Jahren 1836 und 1837 von Gr. Fuss, A. Sawitsch und G. Sabler ausgeführten Messungen... zusammengestellt von G. Sabler. Im Auftrage der Akademie herausgegeben von W. Struve". For his work, which he wrote about in 1839, he received a doctoral degree, and subsequently graduated that same year.
Astronomer
From 1839 to 1854 Sabler worked as an assistant and senior astronomer at the Pulkovo Observatory near St. Petersburg, where Struve was the director. Actively partaking in astronomical research, Sabler was then assigned the task of measuring the exact coordinates of stars using a large meridian circle. From 1844 to 1853, Sabler and Carl Friedrich Tenner participated in the construction of the Struve Geodetic Arc in modern-day Finland, Bessarabia, and Ukraine. In Ukraine, specifically the Khotynsky district, the scientists chose the prevailing heights of the area, which were located near the villages of Romankivtsi, Shebutyntsi, Selishche, and Hrubno. Sabler lived in Romankivtsi for more than a week. The results of the research were published in the bulletin of the Imperial Russian Geographical Society, the journal of the Ministry of National Education, and others.
Sabler also participated in measuring the longitude difference between the Pulkovo Observatory and Altona Observatory. In his free time, Sabler polished lenses, successfully making quality achromatic lenses using two glasses of crown glass between which lay a transparent liquid with the appropriate refractive and light scattering coefficients. The lenses were described in the St. Petersburg Academy of Sciences's newsletter. One of Sabler's prism lenses has survived to this day and is an exhibition in the Vilnius University Science Museum.
Activity in Vilnius
After coming to Vilnius, Sabler determined the geographical position of one of the points used for measuring the Struve Geodetic Arc near the village of Nemėžis. From 1854 to 1865, Sabler was director of the Vilnius University Astronomical Observatory. Sabler sent his assistant and fellow astronomer Matvey Gusev for an internship to England in 1858–1860, where they learned of the appliance of photography in astronomy in Kew Observatory, famously pioneered by astronomer Warren De la Rue. On 19 April 1861, Sabler participated in a meeting hosted by the St. Petersburg Academy of Sciences' physics and mathematics department in Pulkovo. In the meeting, Sabler argued that the university's observatory required a solar telescope, emphasizing that the observatory should direct all efforts for astrophysics research of sunspots and star photometry instead of traditional astrometry.
In 1862–1864, while in Great Britain, Sabler observed the development of the solar telescope. He successfully ordered one of the solar telescopes after negotiations with John Henry Dallmeyer and permission from Struve. In 1864, the Vilnius observatory successfully received its own solar telescope and produced one of the first pictures of sunspots. The telescope would be destroyed in a fire in 1876. Sabler used a method of coating the photographic plate with collodion, which was a method invented in 1850. Firstly, the glass would be filled with a nitrocellulose solution enriched with iodides and bromides and dried. Before photographing, the plate would be further sensitized by dipping it in a solution of silver nitrate and silver iodide. The prepared photographic plate had to be exposed for 10 or 15 minutes and developed immediately.
The establishment of a new solar telescope meant a reconstruction of the observatory's towers. However, as Sabler became increasingly sick, he made Gusev responsible for the continuation of his works. Sabler traveled to St. Petersburg for treatment, after which he became less ill, but only for a short time. In autumn of 1865 the illness, which was a brain tumor, began to rapidly progress. Sabler's scientific work continued to be worked upon in the observatory by Gusev and Pyotr Smyslov.
Death
Sabler died on 7 December 1865 in Vilnius. He was buried in the Vilnius Evangelical Lutheran Cemetery. The grave was destroyed during the Soviet occupation of Lithuania.
Remembrance
A commemorative plaque was uncovered in his home village of Haljala on 24 June 1991.
References
1810 births
1865 deaths
University of Tartu alumni
Baltic-German people
Astronomers
Geodesists from the Russian Empire | Georg Thomas Sabler | [
"Astronomy"
] | 1,476 | [
"Astronomers",
"People associated with astronomy"
] |
77,396,603 | https://en.wikipedia.org/wiki/Mini-puberty | Mini-puberty is a transient hormonal activation of the hypothalamic-pituitary-gonadal (HPG) axis that occurs in infants shortly after birth. This period is characterized by a surge in the secretion of gonadotropins (LH and FSH) and sex steroids (testosterone in males and estradiol in females), similar to but less intense than the hormonal changes that occur in puberty during adolescence. Mini-puberty plays a crucial role in the early development of the reproductive system and the establishment of secondary sexual characteristics.
Physiology
Hypothalamic-pituitary-gonadal axis activation
Mini-puberty begins within the first few days or weeks of life and typically lasts until 6–12 months of age. The HPG axis is temporarily reactivated, resulting in increased secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. GnRH stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn stimulate the gonads (testes in males and ovaries in females) to produce sex steroids.
Hormonal changes
Males: There is a significant increase in testosterone levels, peaking around 1–3 months of age and leveling off around 6 months. This rise in testosterone is essential for the development of male genitalia, testicular descent, and the proliferation of Sertoli and Leydig cells.
Females: There is an increase in estradiol and FSH levels, although less pronounced compared to the hormonal changes in males. This rise in estradiol is involved in the maturation of ovarian follicles and the growth of the uterus and levels off around 2 years of life. FSH peaks at 1–3 months, similar to boys, but may remain elevated for 3–4 years of life.
Clinical significance
Developmental role
Mini-puberty is crucial for several developmental processes, including:
Sexual differentiation: In males, the surge in testosterone supports the continued development of male genitalia and other secondary sexual characteristics.
Growth and metabolism: The hormonal changes may have effects on growth patterns, bone maturation, and overall metabolism.
Neurodevelopment: Sex steroids play a role in brain development and may influence behaviors and cognitive functions, including language development.
Diagnostic marker
Mini-puberty can serve as a valuable diagnostic window for identifying congenital abnormalities of the HPG axis or gonads. Conditions such as congenital hypogonadotropic hypogonadism and certain forms of intersex can be diagnosed during this period by evaluating hormone levels and gonadal response.
Potential disorders
Disruptions in the mini-puberty process can lead to various clinical conditions, including:
Delayed or absent mini-puberty: This may indicate underlying issues with the HPG axis or gonads, requiring further investigation and potential intervention.
Environmental influences
Environmental factors, such as exposure to Endocrine Disrupting Chemicals (EDCs), have been shown to impact mini-puberty. EDCs are widespread in daily life and can be found in products such as pesticides and personal care items. Bisphenol A (BPA) and many phthalates are known to interfere with the earlier HPG axis activation during pregnancy for boys, affecting testosterone levels during mini-puberty, anogenital distance (AGD), and testicular descent.
More recently, BPA and phthalate exposure during mini-puberty have been shown to interfere with HPG axis activation and testosterone levels during that same time frame, suggesting that mini-puberty is a particularly vulnerable window for EDC exposure. Such disruptions may lead to long-term consequences, including delayed or precocious puberty, reproductive health issues, and increased risk of conditions like polycystic ovary syndrome (PCOS), breast cancer and prostate cancer.
In a small study, it was shown that "PCDD/Fs and PCBs measured in breast milk collected within the first 3 weeks following birth were more strongly associated with sexually dimorphic outcomes than exposures measured in maternal blood collected between weeks 28 and 43" of pregnancy, adding evidence that EDC exposure during mini-puberty may interfere with endocrine and neurological development.
Research and future directions
Although the phenomenon has been known for over 40 years, research into mini-puberty continues to uncover its broader implications for long-term health and development. The potential impact of environmental factors and endocrine disruptors on mini-puberty is an area of active investigation. At the same time, researchers also investigate if mini-puberty may be a window to treat certain disorders, e.g. treating micropenis using gonadotropin (testosterone) injections.
See also
Development of the endocrine system
References
Endocrine system
Human biology | Mini-puberty | [
"Biology"
] | 1,015 | [
"Organ systems",
"Endocrine system",
"Human biology"
] |
77,396,736 | https://en.wikipedia.org/wiki/Cross-cockpit%20collimated%20display | A cross-cockpit collimated display (CCCD) is a display system used in full flight simulators (FFS) to provide the crew with a high-fidelity out-the-window (OTW) view of the simulated environment around the aircraft. It is called cross-cockpit collimated because the light from a projected distant object is composed of rays that remain parallel or near-parallel across the cockpit (which typically sits two pilots side-by-side). Therefore, the projected object appears to both pilots to be realistically located in the distance, where the real object would be.
The technology was developed in the early 1980s by the British electronics company Rediffusion, and has since become the industry standard for FFS visual systems.
Design
In the real world, the rays of light emitted by a distant source are virtually parallel to each other when they reach two observers standing side-by-side (Figure 1). This also means that the same observer moving around from one position to the other, or simply moving their head, will see the distant object as stationary within their field of view, with its light always coming from the same direction.
Early digital visual systems for flight simulators consisted in one or more translucent screens, directly illuminated by one or more projectors from the opposite side to the observer (Figure 2). From the observer's point of view, it is as if the source of light lay on the screen, much like what happens with a TV screen. Since the screen is only a few meters away from the observer, the light from the image of the distant object will appear to come from different directions as the observer moves around, giving the impression that the object is close by instead of far away.
In a typical CCCD, instead, the screen is replaced by a curved mirror, which reflects the image from the translucent back-projection screen, now placed above the cockpit (Figure 3). Thank to the properties of parabolic mirrors, the rays of light from the screen are reflected by the mirror largely all in the same direction; that is they become collimated, and will give the observer the impression that the object represented is indeed distant.
History
The cross-cockpit collimated display was first developed by British firm Rediffusion in Crawley, West Sussex, under the direction of development manager Stuart Anderson. Launched in 1981, the system was patented under the name WIDE – Wide-angle Infinity Display Equipment. After the patent expired, it was adopted by full flight simulator manufacturers worldwide, and remains to this day the standard for FFS visual systems.
References
External links
Display technology | Cross-cockpit collimated display | [
"Materials_science",
"Engineering"
] | 528 | [
"Glass engineering and science",
"Electronic engineering",
"Optical devices",
"Display technology"
] |
77,397,263 | https://en.wikipedia.org/wiki/NGC%206649 | NGC 6649 is an open cluster in the constellation Scutum. It was discovered by William Herschel on 10 July, 1787. The cluster is about 40–60 million years old and it is located 4,500 light years away. Cepheid variable V367 Scuti is a member of the cluster.
NGC 6649 is a rich cluster with more than a thousand members with apparent magnitude over 20 extending at a radial distance of about 21 arcminutes, with the core of the cluster having a radius of 2.4 arcminutes, which corresponds to 1.4 parsecs at the distance of the cluster. The tidal radius of the cluster is estimated to be arcminutes, which corresponds to about 21 parsecs at the distance of the cluster, indicating a cluster with a dense core and an extended halo. Two smaller clusters have been detected in the vicinity of the cluster, forming a triple system.
The turnoff point of NGC 6649 is estimated to be at 4.8 , which corresponds to a spectral type of B5. A total of 59 stars are estimated to be of spectral type B, indicating an original star mass of about 2,600 . Two red supergiants are also members of the cluster based on the reddening, along with a Cepheid variable, V367 Scuti. Seven members of the cluster are found to be Be stars, and the cluster hosts two blue straggler star candidates. The metallicity of the cluster is estimated to be [Fe/H] = +0.02 ± 0.07, slightly below the expected value based on the mean galactic gradient.
References
External links
Open clusters
Scutum (constellation)
6649
Astronomical objects discovered in 1787
Discoveries by William Herschel | NGC 6649 | [
"Astronomy"
] | 361 | [
"Scutum (constellation)",
"Constellations"
] |
77,397,330 | https://en.wikipedia.org/wiki/NGC%205626 | NGC 5626 is a lenticular galaxy in the constellation of Hydra. Its velocity with respect to the cosmic microwave background is 7,120 ± 20km/s, which corresponds to a Hubble distance of 105.0 ± 7.4Mpc (∼342million light-years). It was discovered by British astronomer John Herschel on 30 March 1835.
One supernova has been observed in NGC5626: SN2023kyb (type Ia, mag.17.679) was discovered by ATLAS on 17 June 2023.
See also
List of NGC objects (5001–6000)
References
External links
5626
051794
-05-34-015
Lenticular galaxies
Hydra (constellation)
18350330
Discoveries by John Herschel | NGC 5626 | [
"Astronomy"
] | 155 | [
"Hydra (constellation)",
"Constellations"
] |
77,397,554 | https://en.wikipedia.org/wiki/Faraoni%20Thermal%20Excursion | The Faraoni Thermal Excursion (FTX) was a hyperthermal event that occurred during the Hauterivian stage of the Cretaceous period, being induced by flood basalt volcanism. It is associated with an oceanic anoxic event (OAE).
Causes
The FTX is associated with a pulse of large igneous province (LIP) activity indicated by increased environmental mercury loading, suggesting that massive volcanism was its cause like other Cretaceous OAEs. The OAE was exacerbated by enhanced recycling of sedimentary phosphorus back into the water column under anoxic conditions, which acted as a positive feedback loop that facilitated more eutrophication and deoxygenation.
Timing and duration
The FTX occurred around 131 Ma. The burst of LIP volcanism that kickstarted the FTX occurred about 375 kyr before the deposition of organic-rich layers associated with oceanic deoxygenation.
Anoxia
The FTX caused an anoxic event, which was initially believed to be limited to the Tethys Ocean but has since been found to have affected other marine regions. In some studied sections, there was only dysoxia and not outright anoxia.
Biotic effects
Planktonic foraminifera with elongated chambers radiated during the FTX, with their radiation driven not just by increased incidence of anoxia in the upper water column but also by increased productivity, seasonality, and stratification.
See also
Weissert Event
Selli Event
Paquier Event
Amadeus Event
Breistroffer Event
Bonarelli Event
References
Anoxic events
Hauterivian Stage | Faraoni Thermal Excursion | [
"Chemistry"
] | 327 | [
"Chemical oceanography",
"Anoxic events"
] |
77,398,474 | https://en.wikipedia.org/wiki/Carlo%20Floriani | Carlo Floriani was an inorganic chemist who gained renown for contributions to organometallic and coordination chemistry. He was born in Casalmaggiore, Cremona (Italy) in 1940 and died in 2005. He held positions at the University of Pisa, Columbia University, and Ecole Polytechnique, Lausanne. He had been a protoge of Fausto Calderazzo.
His contributions included small molecule activation including carbon dioxide complexes and dinitrogen complexes. He prepared several transition metal mesityl complexes such as tetramesityldiiron and gold mesityl.
He was recognized with the Centenary Prize, Royal Society of Chemistry.
References
1940 births
2005 deaths
Inorganic chemists
Italian chemists
Metal carbon dioxide complex | Carlo Floriani | [
"Chemistry"
] | 148 | [
"Inorganic chemists"
] |
77,398,579 | https://en.wikipedia.org/wiki/Fausto%20Calderazzo | Fausto Calderazzo was an Italian inorganic chemist. He gained renown from numerous contributions in inorganic chemistry and organometallic chemistry. Hr was born in Parma, on March 8, 1930, where his father served in the Royal Italian army. He died in Pisa on June 1, 2014, at the age of 84.
Life and education
Fausto Calderazzoe entered the University of Florence, in November 1947. He worked in the laboratory of Luigi Sacconi. After the compulsory military service, Calderazzo joined the research group of Giulio Natta, a future Nobel laureate in Milan. He was a postdoctoral fellow with F. A. Cotton. His first independent position was at the Cyanamid European Research Institute in Geneva (1963-1968). There he was part of a team of future eminent scholars, including Carlo Floriani. For most of his career he was professor at the University of Pisa.
Research
Metal carbonyl chemistry
While in Milan, he discovered V(CO)6. He made seminal contributions to the mechanism of migratory insertion reactions, with emphasis on the stereochemical course of the carbonylation of CH3Mn(CO)5. His team later (in Pisa) developed syntheses of Na[Nb(CO)6] and Na[Ta(CO6)].
He contributed to the so-called "non classical" carbonyl compounds through studies on gold complexes.
Metal halides
Calderazzo extended his interest in carbonyl chemistry of the late transition metals halides. His group reported Au4Cl8, a simple mixed-valence gold chloride.
Early metal complexes
Many of his contributions focused on early transition metals. He carried out research on carbon dioxide complexes.
Starting with the preparation of V(η6-1,3,5-C6H3Me3)2, his group prepared many bis-mesitylene derivatives.
Awards and titles
Calderazzo was a member of the editorial or advisor board of international scientific journals. He was a member of the Société Royale de Chemie (1987), Società Chimica Italiana and Accademia Nazionale dei Lincei (1989). He received the A. Miolati award in Inorganic Chemistry in 1988 and the L. Sacconi Medal in 1998.
References
1930 births
2014 deaths
Inorganic chemists
Italian chemists | Fausto Calderazzo | [
"Chemistry"
] | 478 | [
"Inorganic chemists"
] |
77,398,814 | https://en.wikipedia.org/wiki/Musical%20escapism | Musical escapism is a psychological phenomenon characterized by the use of music to elicit vivid daydreams and imaginative scenarios, facilitating a temporary disconnection from immediate surroundings. This practice, a subset of the broader concept of escapism, involves active cognitive engagement, wherein listeners become participants in self-constructed narratives inspired by and synchronized with musical stimuli. The term was coined by Dorsa Rohani at the University of Toronto.
Variety of daydreaming
Musical escapism exists on a spectrum, ranging from casual, brief episodes to more immersive, prolonged experiences.
The phenomenon primarily serves as a medium for entertainment and creative expression to cope with subconscious stressors and anxieties. However, it is not entirely confined to those seeking solace from adversity; rather, it is a diverse phenomenon with broad appeal, engaging individuals across various life circumstances and psychological states. It involves constructing vivid, imaginative scenarios synchronized with the auditory experience. These mental constructs may include self-projections, original characters, or adaptations of existing fictional entities within various contexts. The scenarios can range from purely fantastical narratives to idealized representations of real-life situations.
Musical escapism in media
Musical escapism is not officially recognized as a mental disorder, and has attracted significant attention from social media outlets since 2020. Around the same time, a trend known as "reality shifting" appeared on TikTok. This trend, similar to intense daydreaming and frequently set to music, became an extremely prevalent internet phenomenon.
Musical escapism vs. maladaptive daydreaming
Maladaptive daydreaming is a psychological condition marked by excessive and immersive fantasies that interfere with daily functioning, leading to concentration difficulties, social withdrawal, and neglect of responsibilities. In contrast, musical escapism is a controlled psychological response to music driven by emotion and occasionally subconscious stress, typically without impairing daily life.
The primary differences between maladaptive daydreaming and musical escapism lie in the nature of the activity, degree of control, and individual impact. Maladaptive daydreaming involves uncontrollable and immersive fantasy, leading to significant functional impairment and distress, whereas musical escapism is a controlled activity that generally influences and is influenced by emotional well-being, and can have both positive and negative psychological effects.
See also
Absorption (psychology)
Dissociation (psychology)
Escapism (disambiguation)
Fantasy-prone personality
Musicology
References
Cognitive psychology
Human activities
Music psychology
Musicology
Psychological concepts
Psychology | Musical escapism | [
"Biology"
] | 518 | [
"Human activities",
"Behavior",
"Human behavior",
"Behavioural sciences",
"Cognitive psychology",
"Psychology"
] |
77,400,132 | https://en.wikipedia.org/wiki/Nonperson%20treatment | Nonperson treatment is a level of social interaction at which one person does not acknowledge the presence of another person. The concept was introduced by American sociologist, social psychologist Erving Goffman. For comparison, Goffman describes two other levels of social interaction: " civil inattention", whereby some form of subtle, implicit acknowledgement is provided, and "encounter", which is an explicit engagement.
Goffman gives examples of people commonly subject to nonperson treatment: "... it may be seen in our society in the way we sometimes treat children, servants, Negroes, and mental patients." Panhandlers are another category of people who receive the nonperson treatment. Goffman, in his 1953 Ph.D. thesis writes:
We are familiar with treatment of a person as virtually absent in many situations. Domestic servants and waitresses, in certain circumstances, are treated as not present and act, ritually speaking, as if they were not present. The young and, increasingly, the very old,
may be discussed “to their faces” in the tone we would ordinarily use
for a person only if he were not present. Mental patients are often
given similar non-person treatment. Finally, there is an increasing
number of technical personnel who are given this status (and take
the non-person alignment) at formally organized interplays. Here we
refer to stenographers, cameramen, reporters, plainclothes guards,
and technicians of all kinds.
Following the theory of Goffman for nonperson treatment as a technique of diminishing the social status of a person, Roscoe Scarborough applies it to inequal treatment of contingent faculty in American higher education and Jon Frederickson and James F. Rooney do the same for free-lance musicians.
Chapter 7 of the book Absentees: On Variously Missing Persons by Daniel Heller-Roazen contains a discussion of Erving Goffman’s work on social participation and exclusion, in particular, the concept of "nonperson treatment".
See also
capitis deminutio
civil death
unperson from Nineteen Eighty-Four: a person who has been executed or has fallen out of favor; whose entire history has been erased.
Personhood
Untouchability
References
Interpersonal relationships
Erving Goffman | Nonperson treatment | [
"Biology"
] | 464 | [
"Behavior",
"Interpersonal relationships",
"Human behavior"
] |
77,400,235 | https://en.wikipedia.org/wiki/NGC%205416 | NGC 5416 is a spiral galaxy and radio galaxy located in the constellation Boötes. Its speed relative to the cosmic microwave background is 6,499 ± 18 km/s, which corresponds to a Hubble distance of 95.9 ± 6.7 Mpc (∼313 million ly). NGC 5416 was discovered by German-British astronomer William Herschel in 1784.
The luminosity class of NGC 5416 is III-IV and it has a broad HI line. According to the SIMBAD database, NGC 5416 is a radio galaxy.
To date, 25 non-redshift measurements yield a distance of 80.152 ± 12.462 Mpc (∼261 million ly), which is within the Hubble distance values. Note that it is with the average value of independent measurements, when they exist, that the NASA/IPAC database calculates the diameter of a galaxy and that consequently the diameter of NGC 5416 could be approximately 41, 8 kpc (∼136,000 ly) if we used the Hubble distance to calculate it.
NGC 5423 group
NGC 5416 is part of the NGC 5423 group, the brightest galaxy in this group. This group of galaxies has at least four members. The other three galaxies in the group are NGC 5409, NGC 5423 and NGC 5424.
See also
List of NGC objects (5001–6000)
List of spiral galaxies
External links
NGC 5416 at NASA/IPAC
NGC 5416 at SIMBAD
NGC 5416 at LEDA
NGC 5416 at SEDS
NGC 5416 (DSS2) at WikiSky
NGC 5416 (SDSS) at WikiSky
NGC 5416 (GALEX) at WikiSky
NGC 5416 at Seligman
References
08944
049991
Astronomical objects discovered in 1784
+02-36-014
5416
Unbarred spiral galaxies
Radio galaxies
Boötes
Discoveries by William Herschel | NGC 5416 | [
"Astronomy"
] | 394 | [
"Boötes",
"Constellations"
] |
77,400,500 | https://en.wikipedia.org/wiki/NGC%20682 | NGC 682 is a lenticular galaxy in the constellation of Cetus. Its velocity with respect to the cosmic microwave background is 5,338 ± 26km/s, which corresponds to a Hubble distance of 78.7 ± 5.5Mpc (∼257million light-years). It was discovered by German-British astronomer William Herschel on 30 December 1785.
One supernova has been observed in NGC682: SN2023xtg (type Ia, mag.18.1) was discovered by Kōichi Itagaki on 14 November 2023.
See also
List of NGC objects (1–1000)
References
External links
0682
006663
Cetus
17851230
Discoveries by William Herschel
-03-05-022
lenticular galaxies | NGC 682 | [
"Astronomy"
] | 159 | [
"Cetus",
"Constellations"
] |
77,400,508 | https://en.wikipedia.org/wiki/Hecke%20eigensheaf | In mathematics, a Hecke eigensheaf is any sheaf whose value is based on an eigenfunction. It is an object that is a tensor-multiple of itself when formed under the integral transform of a Hecke correspondence. Hecke eigensheaves are part of the geometric Langlands correspondence.
References
Sheaf theory | Hecke eigensheaf | [
"Mathematics"
] | 72 | [
"Mathematical structures",
"Topology stubs",
"Sheaf theory",
"Topology",
"Category theory"
] |
77,400,517 | https://en.wikipedia.org/wiki/NGC%203447 | NGC 3447 is a barred Magellanic spiral galaxy located in the constellation Leo. Its speed relative to the cosmic microwave background is 1,405 ± 34 km/s, which corresponds to a Hubble distance of 20.7 ± 1.5 Mpc (∼67.5 million ly). It was discovered by the British astronomer John Herschel in 1836.
NGC 3447 shows a broad HI line.
With a surface brightness equal to 15.61 mag/am^2, NGC 3443 is classified as a low surface brightness galaxy (LSB). LSB galaxies are diffuse galaxies with a surface brightness less than one magnitude lower than that of the ambient night sky.
To date, four non-redshift measurements yield a distance of 13.730 ± 9.802 Mpc (∼44.8 million ly), which is slightly outside the range values of Hubble.
NGC 3447A
NGC 3447A, also known as UGC 6007, is an irregular galaxy in contact with NGC 3447. It has roughly the same apparent magnitude, and has a slightly lower surface brightness. Due to gravitational forces, it has become distorted, showing disrupted spiral arms and remnants of its spiral structure, hinting it might have been a spiral galaxy in the past.
Supernova
The supernova SN 2012ht (type Ia, mag. 18.6) was discovered in NGC 3447 by Koichi Nishiyama and Fujio Kabashima on December 18, 2012.
NGC 3447 group
NGC 3447 is the largest galaxy in a group of galaxies named after it. The NGC 3447 group includes at least 4 other galaxies: NGC 3447A, NGC 3457, UGC 6022 and UGC 6035.
See also
List of NGC objects (3001–4000)
List of spiral galaxies
External links
NGC 3447 at NASA/IPAC
NGC 3447 at SIMBAD
NGC 3447 at LEDA
NGC 3447 at SEDS
NGC 3447 (DSS2) at WikiSky
NGC 3447 (SDSS) at WikiSky
NGC 3447 (GALEX) at WikiSky
NGC 3447 at Seligman
References
Magellanic spiral galaxies
Barred spiral galaxies
Interacting galaxies
Discoveries by John Herschel
Astronomical objects discovered in 1836
3447
06006
32694
IRAS catalogue objects
Leo (constellation) | NGC 3447 | [
"Astronomy"
] | 476 | [
"Leo (constellation)",
"Constellations"
] |
77,400,682 | https://en.wikipedia.org/wiki/NGC%203187 | NGC 3187, also known as HGC 44D, is a large barred spiral galaxy located in the constellation Leo. Its velocity relative to the cosmic microwave background is 1,901 ± 22 km/s, which corresponds to a Hubble distance of 28.0 ± 2.0 Mpc (∼91.3 million ly). NGC 3187 was discovered by Irish physicist George Stoney in 1850.
The luminosity class of NGC 3187 is III and it has a broad HI line. It also contains regions of ionized hydrogen.
With a surface brightness equal to 15.30 mag/am^2, NGC 3187 is classified as a low surface brightness galaxy (LSB). LSB galaxies are diffuse galaxies with a surface brightness less than one magnitude lower than that of the ambient night sky.
To date, eight non-redshift measurements yield a distance of 25,700 ± 10,409 Mpc (∼83.8 million ly), which is within the Hubble distance range.
Hickson 44
NGC 3185 (HCG 44c), NGC 3187 (HCG 44d), NGC 3190 (HCG 44a) and NGC 3193 (HCG 44b) form the Hickson Compact Group HCG 44. The galaxies NGC 3187, NGC 3190 and NGC 3193 appear in the Atlas of Peculiar Galaxies under the designation Arp 316.
See also
Leo II Groups
List of spiral galaxies
External links
NGC 3187 at NASA/IPAC
NGC 3187 at SIMBAD
NGC 3187 at LEDA
NGC 3187 at SEDS
References
Barred spiral galaxies
Leo (constellation)
3187
30068
05556
316
Astronomical objects discovered in 1850
Hickson Compact Groups | NGC 3187 | [
"Astronomy"
] | 351 | [
"Leo (constellation)",
"Constellations"
] |
74,469,613 | https://en.wikipedia.org/wiki/WELL%20Building%20Standard | WELL Building Standard (WELL) is a healthy building certification program, developed by the International WELL Building Institute PCB (IWBI), a California registered public benefit corporation.
History
The WELL Building Standard began in 2013 by Paul Scialla of Delos company, becoming the first well-being focused standard. By 2016, over 200 projects in 21 countries adopted the certification. In 2014, Green Business Certification Inc. began to provide third-party certification for WELL. By 2024, WELL is being used across more than 5 billion square feet of space in 130 countries, supporting an estimated 25 million occupants in nearly 74,000 commercial and residential locations.
Principles & concepts
WELL v2 met best practices on four tenets: evidence-based, verifiable, implementable, and feedback-focused. The principles in WELL v2 are equitable, global, evidence-based, technically robust, customer-focused, and resilient. WELL is a performance-based system which Performance Verification is completed by an authorized WELL Performance Testing Agent.
Certification
There are two types of certifications, the WELL Certification for Owner-occupied and the WELL Core Certification.
The WELL Core is for the building that provide tenant occupation more than 75%, and not needed to achieve minimum points from every subjects.
The WELL Silver, Gold, and Platinum level must achieve at least 1, 2, and 3 points per subject, but the WELL Bronze has no minimum points' rule. For WELL core, there are no minimum point.
The optimization point requirement from the WELL Bronze, Silver, Gold, and Platinum are ranging from 40, 50, 60, and 80 points. The rating system limits 12 points per subject, except the Innovation which limit under 10 points. Total points must not be over 100.
Assessment
The WELL certificated buildings must pass all precondition requirements and they could get optimization points available from extension subjects.
Air
Because users spend 90% time in interior, they can expose to indoor air pollutions that lead to headaches, dry throat, eye irritation, runny nose, asthma attacks, infection with legionella bacteria and carbon monoxide poisoning. It leads to thousands of cancer death and 100,000 of respiratory issues annually. Avoidable costs in the U.S. could be over 100 billion dollars annually 45% from radon and tobacco and 45% from lost productivity, and 10% respiratory diseases. Combustion sources such as candles, tobacco, stoves, furnaces, fireplaces producing carbon monoxide, nitrogen dioxide, and small particles are common. Furnishings, fabrics, cleaning product emit volatile organic compound (VOCs). It could be resolved by eliminate problem sources and design solutions. Air pollution leads to 7 millions premature deaths, around 600,000 of those were children under 5 years old in 2012.
A01-A04 Precondition
A01 Air Quality topic, the WELL conducts to limit level of particulate matter both PM2.5 and PM10 under 15 and 50 for normal region or 25 and 50 microgram/cubic metre or 30% of 24–48 hours average of outdoor levels for polluted region and thresholds for volatile organic compound (VOC) such as benzene, formaldehyde, toluene to 10, 50, and 300 microgram/cubic metre or total VOC of 500 microgram/cubic metre. Inorganic gases such as carbon monoxide and ozone are also limited to 10 milligram per cubic metre and 100 microgram/cubic metre. Radon is limited under 0.15 Becquerel/Litre. WELL makes sure that all air quality shall be monitored with a digital platform, except for radon parameter.
A02 Smoke-free Environment topic, smoking and using of electronic cigarette indoor is not allowed, except for outdoors at only ground level further than 7.5 m from project apertures including air-intake area.
A03 Ventilation Design topic, the WELL assured building to have existing or new mechanical ventilation systems following ASHRAE 62.1-2 or EN standard 16798-1 or AS 1668.2 or CIBSE Guide A: Environmental Design. Naturally ventilation can also be used without mechanical ventilation system if the design follows Natural Ventilation Procedure in ASHRAE 62.1, CIBSE AM10, AS 1668.4 at least 90% of the project area. Ventilation monitoring can be only solution if carbon dioxide level is met under 900 ppm indoor and 500 ppm outdoor.
A04 Construction Pollution Management topic, the contractor is to ensure that ducts are cleaned and protected from contamination. Contractor shall filter with more than 70% efficiency for particles 3-10 micrometers on the installed ventilation system during construction. Contractor must implement dust and moisture management such as using of temporary barriers, dust guards for saws, walk-off mats on entryway.
A05 - A14 Optimization
A05 Enhanced Air Quality topic, enhancing threshold of particulate matter both PM2.5 and PM10 under 12 and 30 for 1 point, 10 and 20 for 2 points. Enhancing volatile organic compound such as benzene, formaldehyde, toluene under 3, 9, 300 microgram/cubic metre and additional acetaldehyde, acrylonitrile, caprolactam, naphthalene under 140, 5, 2.2, 9 microgram/cubic metre would receive 1 point. Inorganic gases such as carbon monoxide and nitrogen dioxide under 7 milligram per cubic metre and 40 microgram per cubic metre receives additional 1 point.
A06 Enhanced Ventilation Design topic threshold of mechanical and natural ventilation or with demand controlled ventilation (DCV) or engineered natural ventilation system to keep CO2 levels low, or at least 50% of workstations are supplied in the breathing zone with an airspeed under 50 fpm at user's head receives 2 points. Displacement ventilation system implement or air diffusers located 2.8 m above the floor receives additional 1 points.
A07 Operable Windows, providing openable windows to access to outdoor air, available to access outdoor air by 75% of regularly occupied areas or 4% of the occupied areas of there are many floors receives 1 point, another 1 point, if there is outdoor air quality for PM2.5, temperature, relative humidity display near windows.
A08 Air quality monitoring and Awareness topic, installing air quality sensor and submitting data to WELL provides 1 point and display screens available in the building to promote awareness provides another 1 point.
A09 Pollution Infiltration Management topic, entrance way design such as 3 meters' air door and to slow movement of air from outdoor to indoor by building vestibule or revolving doors, air curtain and management by wet cleaning once a week, vacuuming once a day provides 1 point and envelope of building that is designed to mitigate outside air pollution provides another 1 point.
A10 Combustion Minimization topic, combustion restriction indoor or keeping away from building 3.3 meter and vehicle running limitation of 30 seconds.
A11 Source Separation topic by to remove the sources by design separately closed door, negatively pressurized or exhaust fans such as the return air to outdoor of all bathrooms, kitchens, cleaning and chemical storage, high-volume printers and copiers provides 1 point.
A12 Air Filtration topic by using media filters in ventilation system or standalone device by appropriate efficiency to filter outdoor air, the higher PM2.5, the higher efficiency from 35% to 95% and keep replacing annually provides 1 point.
A13 Enhanced Supply Air topic by ventilating occupied spaces with all outdoor air or cleaning devices such as activated carbon filter with efficiency of 75% or media filter or Ultraviolet germicidal irradiation (UVGI) under UL 2998 Zero Ozone Emissions Validation or Intertek Zero Ozone Verification provides 1 point.
A14 Microbe and Mold Control topic by implement ultraviolet radiation system for HVAC coil each provides 1 point.
Water
WELL Water aims to increase the rate of adequate hydration in building and reduce risks due to contaminated water. Human's body is two-thirds water, recommended water intake around 2 - 3.7 litres per day to let respiration, perspiration and excretion works. Water with high nitrate can impair oxygen transport in infants, causing neurodevelopment impair. Trihalomethane (THMs) and haloacetic acids (HAAs) in water can cause cancer. Legionella control is needed in cooling systems and hot tubs. Materials must not support mold growth. Well bathroom design, better hand washing leads to reduce risks enteric and respiratory diseases.
W01 - W03 Precondition
For W01 Water Quality Indicators, WELL conducts by performance test to limit turbidity of water under 1.0 Nephelometric Turbidity Unit (NTU) or Formazin Turbidity Unit (FTU) or Formazin Nephelometric Units (FNU). Water sample of any 100 ml shall have zero coliform bacteria.
For W02 Drinking Water Quality, the project requires drinking water that limits chemical contamination of arsenic, cadmium, chromium, copper, fluoride, lead, mercury, nickel, nitrate, nitrite, chlorine, trihalomethane, and haloacetic acids. Pesticide contamination has to be controlled such as aldrin and dieldrin, atrazine, carbofuran, chlordane, 2,4-Dichlorophenoxyacetic acid, DDT, lindane, pentachlorophenol. Organic contaminants are also limit, such as benzene, benzo(a)pyrene, carbon tetrachloride, 1,2-Dichloroethane, tetrachloroethene, toluene, trichloroethylene, 2,4,6-Tribromophenol, vinyl chloride, and xylene.
For W03, Basic Water Management, annually monitoring is required such as turbidity, pH, residual free chlorine. Legionella management must be determined in the building.
W04 - W08 Optimization
For W04, Enhanced Water Quality, enhancing threshold of drinking water contamination level provides 1 point.
W05, Drinking Water Quality Management provides total 3 points. For 2 points, the project needs pre-testing water quality on the farthest water dispenser for every 10 floors such as turbidity, coliform bacteria, pH, total dissolved solids (TDS), chlorine, residual (free) chlorine, arsenic, lead, copper, nitrate, benzene at least one month before Performance Verification and monitoring piped water that delivers drinking water, testing water from dispensers quarterly. Turbidity must be equal or less than 1.0 NTU. pH must be between 6.5 and 9.0. TDS must be equal or less than 500 mg/L. Total Chlorine must be equal or less than 5 mg. L. Residual (free) chlorine must be equal or less than 5 mg/L. Total Coliforms must not be detected in a 100 ml sample. Lead must be equal or less than 1 micro gram/L. Sampling frequency can be reduced to once a year, if the results are under limit two consecutive times. Copper must be equal or less than 2 mg/L. Sampling frequency can be reduced to two a year. If the results are under limit four consecutive times, then there is no need to monitor anymore. The test result must be submitted to WELL annually. Last part is display of water management information to promote drinking water transparency provides another 1 point.
For W06, Drinking Water Promotion, encouraging people to drink water easily by provide water dispenser minimum one per floor within 30 meter of all users and in all dining areas, designing for water bottle-refilling with maintenance provides 1 point.
W07, Moisture Management provides total 3 points, to limit the bacteria and mold growth, the project needs building envelope that incorporates site drainage and storm water management, air tightness testing, vapor pressure differentials, entryway strategies to minimize water permeation, drainage plane from interior to exterior cladding, limiting wicking in porous materials by using non-porous materials such as closed-cell foams, waterproofing membranes, metal between porous meterials or free-draining spaces, provides 1 point. Using protection or implementing measures to eliminate condensation on cold surfaces such as basement, slab-on-grade floor and liquid water as interior housewrap such as basement, bathroom, kitchen provides another 1 point. Label or manual at point-of-connection to shut-off pipe and all water treatment devices need backflow prevention system such as air gap or backflow preventer valve. The last 1 point is to manage moisture by scheduling inspection, notification system in the building and to submit all inspection result to WELL annually.
W08 Hygiene Support, the highest points in the Water subject, total 4 points. Part 1, 1 point, bathroom needs trash receptacle in toilet stall if toilet paper cannot be flushed, free of 50% subsidized sanitary pads, storage support in toilet stalls, at least one bathroom has wheelchair bathroom, one bathroom per project for infant changing table, syringe drop box, single-user bathroom needs occupancy signage, self-primed liquid-seal trap in floor drain. For public projects such as airport, family bathroom are required, containing changing table for infant, child size toilet and sinks, motion sensor for lights, slip-resistant floor, grab bars, hook or shelf for bags in toilet stall, wheelchair accessibility by local code. Part 2, 1 point, bathroom needs hands-free flushing toilet, contactless soap dispenser and hand-drying, hands-free exiting door, sensor-activated, programmable line-purge faucet. Part 3, 1 point, faucet design avoiding flowing directly into the drain, splash limited inside the sink, minimum width of 23 cm sink size, flowing column of water minimum 20 cm and at least 7.5 cm away from sink edge. Part 4, 1 point, handwashing supply must has fragrance-free liquid soap through sealed dispensers, paper towels or hand dryers with HEPA filter or fabric towel rolls and signage with proper hand washing steps.
Nourishment
WELL Nourishment concept supports healthy and sustainable eating patterns by accessing to fruits and vegetables more and limiting highly processed foods, nudging users to choose better choices. Poor nutrition responses to one in five people death globally. Unhealthy eating is worse than combining of drug, alcohol, and tobacco. Diets usually is low in fruits, vegetables, whole grains, nuts, seeds, but instead flood with highly processed foods such as refined sugars and oils. In 2019, the EAT-Lancet Commission developed best food option. By developing environment conditions that influence users to change diets with holistic approach, supportive policies.
N01 - N02 Precondition
N01 Fruits and Vegetables, WELL ensures to operate food outlet for at least two varieties of fruits and non-fried vegetables that would be clearly be seen by users. Each food outlets are at least 50% of food options are fruits or non-fried vegetables.
N02, Nutritional Transparency, other type of foods such as packaged food and beverage must display the total calories per serving, macronutrient, and sugar content. Owner must communicates users on food allergy. High sugar foods or over than 25 grams of sugar per serving is banned from the menu in dining spaces or at least identified in the items for users to make a decision.
N03 - N13 Optimization
N03 Refined Ingredients, restriction of sugars by limit beverage under 25 g of sugar per container, at least 25% of beverages contain no sugar, and non-beverage food except fruit contain sugar under 25 gram per serving receives 1 point. Whole grains promotion by 50% of grain-based food contains whole grain the most receives another 1 point.
N04 Food Advertising, eliminating sugar drink, deep-fried food advertising, and sale area promotes water, fruits and vegetables consumption instead, receives 1 point.
N05 Artificial Ingredients, phasing out or restrict of artificial ingredients such as colorings, sweeteners, food preservation, fats and oils by clearly labeled on packaging or signage receives 1 point.
N06 Portion Sizes, dining space promoting healthy size of food receives 1 point by limiting portion below 650 kCal or over 650 kcal menu under 50%, and dish or bowl size must not be over certain area or volume. Primary school students, secondary school students, and adults plate size are no more than 20, 25, and 30 cm diameter.
N07 Nutrition Education, providing nutritional knowledge by cooking demonstration or dietary education learning by nutritionist or gardening workshop receives 1 point.
N08 Mindful Eating provides 2 points by dedicating eating space within 200 meters walking distance of the boundary of the project that contains tables and chairs to 25% of users at peak, protects from outdoor climate hazard, provides variety of seating options from small to large group of people, and if there is employees or students then they would provides daily 30 minutes break for meal.
N09 Special Diets, alternative food providing to food allergen person, total 2 points. For part 1, 1 point, providing food at least does not include peanut and tree nuts or gluten and wheat or soy or sesame or animal products including seafood, dairy, and eggs. For part 2, 1 point, clearly labeling on packaging, menus, signage that the food contains peanut, fish, shellfish, soy, milk, egg, wheat, tree nuts, sesame, gluten.
N10 Food Preparation, providing space for user's meal such as cold storage, countertop, sink for dish and hand washing, microwave or toaster, reusable plates, garbage bin receives 1 point.
N11 Responsible Food Sourcing, sourcing 50% foods that are certified organic and 25% animal product lines that are certified organic by Gran Sasso Science Institute (GSSI) or Seafood Certification Scheme by labeling for sustainable receives 1 point.
N12 Food Production receives 2 points by providing garden or greenhouse with food-bearing plants or edible landscape or hydroponic or aeroponic farming which is accessible to users in regular hours and growing area both horizontal and vertical at least 0.09 sq. m per user or 0.05 sq. m per student, except hydroponic and aeroponic farming can be half of normal system, and users can access to food growing tools, in which the area is within 400 meter walking distance.
N13 Local Food Environment, supporting local food by locating the project near fruit and vegetable supermarket or farmers' market that open at least once a week within 400 meters walk distance, or serving local agriculture program or hosting weekly sale of fruits and vegetables receives 1 point.
Light
WELL Lighting concept aims to create lighting that reduces circadian disruption to improve sleep quality and mood and productivity. Humans are diurnal driving by circadian systems or internal clock. Disruption of it leads to obesity, diabetes, depression, breast cancer, metabolic and sleep disorders. Insufficient light can lead to disruption.
L01 - L02 Precondition
L01 Light Exposure, daylighting design hugely integrates in a project by daylight simulation such as the Spatial Daylight Analysis that shows how much daylight illuminates throughout working hours. Adequate daylighting level can be decided on the interior layout or the building design such as a distance from windows. For the project that finds it difficult for daylight access, circadian lighting design can replace daylight such as an Intrinsically photosensitive retinal ganglion cell (ipRGC) receiving enough light at least 150 Melanopic Lux (EML)
L02 Visual Lighting Design, WELL still keeps visual lighting design which is conventional lighting method for user's visual comfort and acuity. Lighting design standard in WELL follows Illuminating Engineering Society Lighting Library or EN standard 12464-1&2 or ISO 8995-1 or Chinese Standard GB 50034 or CIBSE SLL Code for Lighting. Alternately WELL allows light level threshold from U.S. General Services Administration's facilities standards.
L03 - L09 Optimization
L03 Circadian Lighting Design, if the project chose precondition part of circadian lighting, the project receives 1 point automatically. For the project that achieves at least 275 Melanopic Lux (EML), the project receives more 2 points.
L04 Electric Light Glare Control, limiting glare from indoor artificial light, receiving 2 points, by using 100% upward lighting or fixture classified Unified Glare Rating (UGR) equal or under 16 or all fixtures does not exceed 6,000 candela/sq.m at angle between 45 and 90 degrees from bottom, it can be done in lighting calculation software that results in UGR equal or under 16.
L05 Daylight Design Strategies, providing daylight exposure indoors through design strategies. Daylight plan for the project receives 1 point for workstations near the window within 7.5 meters, but if positioned within 5.5 meters, it receives 2 points instead. Integrating of solar shading system with manual control receives 1 point, or with automated control system throughout year receives 2 points instead.
L06 Daylight Simulation, daylight calculation that results equal or higher than 55% of project occupancy area, receiving 300 lux more than 50% of annual time of use, is received 1 point. If it results equal or higher than 75%, then it will be received 2 points.
L07 Visual Balance receives 1 point by either design by at least three of five parameters of luminance ratio of horizontal and vertical plane at maximum 10 times, 0.4 ratio of minimum illuminance and average illuminance on horizontal task plane, using automation system by changing light characters at least light levels over a period at least 10 minutes, using consistent Correlated color temperature (CCT) plus and minus 200 Kelvin, or the project is designed by lighting professional that takes those ratios in account.
L08 Electric Light Quality, for quality of light fixtures, total 3 points, all light fixture, except decorative lights and emergency lights, that color rendering is equal or over color rendering index (CRI) of 90 or CRI of 80 with R9 equal or over than 50 or TM-30 of color rendering fidelity (Rf) equal or more than 78 and color rendering gamut (Rg) equal or more than 100 with Rcs,h1 from -1% to 15%, will receive 1 point, and that flicker of luminaires classified as "reduced flicker operation" or defined 1, 2, 3 recommended practices by IEEE standard 1789-2015 LED or short term light flicker (Pst LM) and Stroboscopic Visibility Measure (SVM) equal or under 1.0 and 0.6 per NEMA 77-2017, will receive 2 points.
L09 Occupant Lighting Control, providing individual control of light for one per 60 sq.m. or one per 10 occupants will be received 1 point, but if there are one per 30 sq.m. or one per 5 occupants, then it will be received 2 points, with the project has lighting control in each zone was setup at least three lighting levels, able to change group of lights with different light beams or color or CCT, all users be able to control light manually by keypad or digital interface, and separately control of lighting for presentation. Task light provided with no cost to employees and light levels and direction can be controlled by users independently under shielded light source receives 1 point.
Movement
To promote physical activity by creating opportunities through spaces is a substantial impact to decrease risk of death by 10% and 25%, which more than half a million and one million people globally would not have died because of inactivity. Global lifespan could increase by 0.68 years. Physical inactivity leads to pre-mature death and chronic illness, type II diabetes, cardiovascular disease, depression, stroke, dementia and cancer. 23% of adult globally are inactive caused by rising urbanization and economic development. Sitting or sedentary globally average 3–9 hours daily among adults that linked to mentioned illnesses.
V01 - V02 Precondition
V01 Active Buildings and Communities, the summary of optimization points which WELL requires the project to achieve as least one point from four optimization features specifically V03 Circulation Network for visible, open to access and aesthetic stair circulation, V04 Facilities for Active Occupants such as cycling network with bike parking or showers, lockers and changing rooms, V05 Site Planning and Selection such as pedestrian-friendly environment or mass transit within walking distance, V08 Physical Activity Spaces and Equipment such as free sport opportunities and facilities or green space for outdoor activities.
V02, Ergonomic Workstation Design, intended for users to adjust furniture freely such as monitor position, work surface height, chair, standing desk and foot support including user's orientation or instruction.
V03 - V10 Optimization
V03 Circulation Network provides total 3 points, designing aesthetic staircase by music, artwork, designed to have light levels of at least 215 lux in use, windows or skylights that provide daylight or nature views, natural design elements, gamification receives 1 point. Integrating point-of-decision signage on stair area such as motivational element receives 1 point. Promoting visible stair that close to the entrance receives 1 point.
V04 Facilities for Active Occupants, providing cycling network and parking for bikes with shortterm and longterm with basic bike maintenance tools and minimum Bike Score® of 50, 200 m walk distance of an existing cycling network receives 2 points, and with showers, lockers, and changing facilities 16 places plus one for every 1,000 occupants receives another 1 point.
V05 Site Planning and Selection, site planning for walking and connection to public transportation minimum Walk Score® of 70 or within a 400 m distance of the project boundary, by selecting sites with friendly streets and friendly footpath receives 2 points, and with walkable distance to mass transit receives another 2 points.
V06 Physical Activity Opportunities, providing physical activity for occupants at no cost, by qualified professional, not in form of punishment by at least one 30-minute event per week or one 60-minute per week for school students receives 1 point, and for not less than total 150 minutes per week or not less 60 minutes per day for school students receive 2 points.
V07 Active Furnishings, providing at least manual or electric work surface or treadmill or stationary bicycle or step machine, and with 50% ot 90% of workstations receives 1 point ot 2 points in this active furnishing.
V08 Physical Activity Spaces and Equipment, providing indoor fitness space at no cost receives 2 points either the space includes two types of exercises or equipment that allow use by at least 5% of occupants at any time or has minimum size of 25 sq. m plus 0.1 sq. m per occupant until 930 sq. m, but WELL also allows if the project gives free pass to access fitness facility within 200 meters walking distance instead.
V09 Physical Activity Promotion receives only 1 point, if the project offer at least two of five activities to employees such as prize from sport competition, subsidy for employee sport member, reducing of health care cost, flexible work hours, paid time off at least four days per year physical activity, and either utilization of incentive program for 50% or improvement at least 10%, and if students are in account, it needs program to reduce TV viewing, computer or smartphone use, gaming, and to teaching physical activity or movement or physical activity breaks.
V10 Self-Monitoring Support, receive only 1 point by providing free fitness tracker at no cost or at least 50%, measuring at least two physical activities and at least one additional activity such as sleep or mindfulness.
Thermal comfort
Holistic approach and intervention to help design building that focus on individual thermal discomfort, which is subjective under the same conditions. One-size-fits all does not suit for large people. Personal thermal control should be used to improve productivity and decrease sick building syndrome. Due to large number of people, thermal comfort conditions should create baseline satisfaction for the largest number of people. It is greatly influencing users and one of the biggest impact to motivation, alertness, focus and mood. It should provide acceptable thermal environment to minimum 80% of users, in fact only 11% met accepted human satisfaction in the U.S., and 41% were dissatisfaction which detrimental to business. Employees perform 15% poorer in hot conditions and 14% poorer in cold conditions.
T01 Thermal Performance Precondition
The first part, WELL ensures thermal indoor environment to be controlled. For HVAC control system (mechanically conditioned space), acceptable thermal comfort by PMV/PPD model must be in between -0.5 and 0.5 over 90% of regularly occupied spaces. For naturally conditioned system, the minimum prevailing mean outdoor temperature (tpma (out)), calculated from average outdoor temperature entire day, must be 10 degrees Celsius and indoor temperature of 31% of the tpma (out) plus 14.3 degrees Celsius. The maximum tpma (out) must be under 33.5 degrees Celsius and indoor temperature of 31% of the tpma (out) plus 21.3 degrees Celsius. For example, the tpma (out) 33.5 degrees Celsius, the indoor temperature shall not be over 31.7 degrees Celsius. If tpma (out) is over than 33.5 degrees Celsius then a mechanically conditioned space would be in place. WELL allows the project to use optimization points from T06 Thermal Comfort Monitoring with dry-bulb temperature data or it can be only thermal comfort surveys by achieving 2 points from T02 Verified Thermal Comfort, 80% satisfaction survey of thermal comfort.
The second part, semi-annual testing on summer and winter for dry-bulb temperature and relative humidity, air speed, and mean radiant temperature or it can only achieve T06 Thermal Comfort Monitoring feature.
T02 - T07 Optimization
T02 Verified Thermal Comfort, if surveying from user results in 80% satisfaction receives 2 points, and 90% satisfaction receives 3 points, with responses significant 35% of 45 users or 15 from 20 users or 80% of 20 users with sample template.
T03 Thermal Zoning, providing thermostat control point one per 60 sq. m and per 30 sq. m or one per 10 users and 5 users would receives 1 and 2 points, by presenting with digital interface on computer or phone, with temperature sensors apart from exterior wall, windows, doors, direct sunlight, air supply diffusers, mechanical fans, heaters, other significant sources of heat or cold.
T04 Individual Thermal Control, giving personal thermal control for both heating and cooling receives each 1 point, for cooling, implementing user-adjustable thermostat, desk fan or ceiling fan, chair with mechanical cooling system, other solution that affecting PMV change of -0.5 within 15 minutes without changing the PMV for other occupants, for heating, implementing user-adjustable thermostat, electric parabolic space heater, electric heated chair or foot warmers, personal or shared blankets, other solution that affecting PMV change of -0.5 within 15 minutes without changing the PMV for other occupants, thus allowing flexible dress code receives another 1 point.
T05 Radiant Thermal Comfort, radiant thermal comfort management for both heating and cooling receives each 1 point by implement radiant ceilings, walls, floors, radiant panels at least 50% of regularly occupied project area.
T06 Thermal Comfort Monitoring such as dry-bulb temperature and relative humidity receives 1 point with display screen and website or mobile application every 500 sq. m of regularly occupied space, and submitting data annually to WELL with proof of calibration.
T07 Humidity Control, control of humidity receives 1 point by having mechanical system that can maintain relative humidity 30% to 60% at all times or submitting document that modeled relative humidity levels in space from 30% to 60% for at least 98% of all business hours or by meeting thermal comfort monitoring (T06) with relative humidity levels from 30% to 60% except high-humidity spaces.
Sound
Providing holistic approach to address acoustical comfort of a space, measuring satisfaction of users by human response to mechanical vibrations through a medium, such as air. Sleep disturbance, hypertension, reduction of mental arithmetic skills in children are caused by exterior noise and HVAC, appliances noises. Myocardial infarction risk can be cause by traffic noise at night. Bad reverberation times and background sound levels can affect speech intelligibility in educational areas where aural comprehension is vital for memory retention. The planning and commissioning of an isolated and balanced HVAC system is firm baseline for anticipated background noise level. Adding facade elements such as mass and glazing, sealing gaps and providing airspace between enclosed spaces can increase occupant comfort. Replacing hard surfaces with absorptive materials improve speech projection and acoustical privacy. Consistent background sound levels is provided by sound masking system, increase the signal-to-noise ratio to increase privacy.
S01 Sound Mapping Precondition
For labeling acoustic zone, interior design must have a design of acoustics zoning label such as loud zone, quiet zone, mixed zone, and circulation zone to mitigate a sound transmission from loud zones to quiet zones.
For providing acoustic design plan, the design concept shall incorporate acoustical comfort, background noise, speech privacy, and reverberation time and/or impact noise within the project boundary, or it can be an acoustical engineering professional in acoustic to evaluate existing sounds and to recommend solutions and measurements.
S02 - S06 Optimization
S02 Maximum Noise Levels, limiting background noise levels over period of five minutes and average sound pressure levels do not exceed tier 1, receiving 1 point, that average Sound pressure level (SPL) for category 1 to 4, 40 dBA to 55 dBA and 60 dBC to 75 dBC, and maximum SPL from 50 to 65 dBA or 70 to 85 dBC. For tier 2, receiving 3 points instead, that average SPL for category 1 to 4, 35 to 50 dBA and 55 dBC to 70 dBC, and maximum SPL from 45 to 60 dBA or 65 to 80 dBC.
S03 Sound Barriers, sound barriers that designed for sound isolation at walls and doors meets Sound transmission class (STC) or Weighted Sound Reduction (Rw) values from minimum 40 STC to 60 STC, and doors with minimum 30 STC would receives 1 point. Achieving minimum Noise Isolation Class (NIC) or Weight Difference Level (Dw) for each wall type from minimum 35 NIC to 55 NIC, or the sum of NIC or Dw combined with Noise Criteria Rating (NC) or Weighted Sound Pressure Level (LAeq) with minimum 70 to 85 NIC + NC or Dw + LAeq would receive 2 points.
S04 Reverberation Time, maintain persistence of voices in the room receives 2 points, for example, area for music rehearsal for maximum 1.1 seconds, area for learning for maximum 0.6 seconds that could be verified by technical document or performance test.
S05 Sound Reducing Surfaces, furnishing quality surfaces of room that meets criteria of tier 1 or 2, receiving 1 or 2 points, for example, open workspaces, minimum noise reduction coefficient (NRC) OR Alpha-w of 0.75 or 0.90 and minimum furniture height and NRC OR Alpha-w with minimum height of 1.2 m above finished floor and minimum 0.70, cumulatively at least 10% of occupied project area.
S06 Minimum Background Sound, artificial background sound by making sound masking system receives 1 point to increase privacy that produce 1/3 octave band output signal and minimum frequency spectrum of 100 Hz to 5 Hz. Providing enhanced speech reduction automatically receives 1 point by achieving 2 points from S03 or S05, and S06 part 1.
Materials
Promoting the use of low-hazard cleaning products and practices that reduce health impact, mitigation of contamination and public health, management of waste, low-hazard pesticides. For some toxic, prone to bioaccumulation materials carrying old chemicals such as lead that accounted of a one million deaths in 2017. CCA in wood structures can leach arsenic in soil where children can be exposed. New materials such as perfluorinated alkyl compounds (PFCs), orthophthalates, some heavy metals and halogenated flame retardants (HFRs) are superior but cause negative health impact. Volatile organic compound (VOCs) are so common in insulation, paints, coatings, adhesives, furniture and furnishings, composite wood products and flooring that cause respiratory issue and cancer risks. Two solutions are to increase knowledge of materials and to promote assessment and selection to minimize impacts.
X01 - X03 Precondition
For X01 Material Restrictions, Asbestos level in newly installed products is limit under 1,000 ppm by weight or area. Mercury content for fluorescent lamp and sodium-vapor lamp is limit to 2.5 mg to 32 mg or passed the Restriction of Hazardous Substances Directive (RoHS). For fire alarms, meters, sensors, relays, thermostats, and load break switches is limit to no more than 1000 ppm of mercury by weight and 100 ppm of lead or certified the RoHS. For newly installed paints, lead content shall not be over than 100 ppm by weight and certified by the Living Building Challenge's Red List or the Cradle-to-cradle design list or Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) and Candidate List of Substances of Very High Concern (SHVC) lists. Drinking water pipes are limit to 0.25% of lead, or labeled as American National Standards Institute (ANSI) or NSF.
For X02 Interior Hazardous Materials Management, if the building was constructed before the enactment of asbestos banning law, an inspector must qualifies for asbestos containing materials (ACM) and performs polarized light microscopy (PLM) or transmission electron microscopy (TEM). ACM must be removed from the project if it was found. Same as an asbestos management, removing process needs to be done if lead containing materials were found in paints. Polychlorinated biphenyl (PCB) is restricted especially in a caulk, it needs to be removed.
For X03 CCA and Lead Management, outdoor materials such as chromated copper arsenate (CCA) is banned. Lead hazard over the limit in bare soil, turf, artificial turf, recycled tire, and paint shall be examined and be removed or replaced.
X04 - X11 Optimization
X04 Site Remediation, assess and mitigate site hazards by remediation process of a risk-based approach to sustainable remediation receives 1 point.
X05 Enhanced Material Restrictions, material of at least 50% of furniture, millwork, fixture is limited 100 Parts-per notation (ppm) of halogenated flame retardants (HFR), polyfluoroalkyl substances (PFAS), lead, cadmium, mercury, or do not contain textiles and plastic at all, and all electrical products have RoHS restrictions would be awarded 1 point. For flooring products are limited 100 ppm of HFR, PFAS, orthophthalates, and insulation products are limited 100 ppm of HFR, and ceiling and wall panels are limited 100 ppm of HFR and orthophthalates, and pipe and fittings are limited 100 ppm of orthophthalates would receive 1 point.
X06 VOC Restrictions, Volatile organic compound restriction from wet-applied products and furniture, architectural and interior products receives 4 points.
X07 Materials Transparency, selecting products with disclosed ingredients, enhanced ingredient disclosure, and third-party verified ingredients receives 1 point for each, total 3 points.
X08 Materials Optimization, at least 25 distinct products having ingredients inventoried to 100 ppm and free of compound listed in the Living Building Challenge's Red List or the Cradle-to-cradle design list or REACH Restriction and Substance of very high concern (SVHC) lists, or products purchased for future repair would receive 1 point. For optimized products, at least 15 distinct products are certified under the Cradle to Cradle Certified, the Living Product Challenge, and the Global GreenTag.
X09 Waste Management, implementing a waste management plan by identification of roles, sources, protocols to clean and track wastes receives 1 point.
X10 Pest Management and Pesticide Use, implementing integrated pest management (IPM) for indoor and outdoor space receives 1 point.
X11 Cleaning Products and Protocols, developing cleaning plan receives 2 points.
Mind
Mental health issue is estimated 14.3% of deaths worldwide, 8 million death per year, including substance use affect 13% of the global burden of disease and 32% of years lived with disability. Alcohol and drug use is significantly premature death, alcohol alone affect 3.3 million deaths and 5% global burden of disease. Depression and anxiety ranking first and sixth place global burden of disease, with depression accounting for 4% global burden of disease and caused the largest disability worldwide.
Global economy lost from depression and anxiety 1 trillion dollars due to lost productivity, 18% of adults experience the condition, over 30% of adults will experience it during their lifetime, despite that, spending to fight the issue were less than 2 dollars per person. High income and low income country, people experience the issue 35-50% and 76-85% without treatment which causes suicide more than 800,000 deaths per years worldwide. Even that, people with the issue have mortality rate 2.2 times higher than normal and a median loss of 10 years life.
The issue could be mitigated by policies, programs, design in workplace promotion, prevention, interventions. Reducing stigma, promoting positive work environments, stress management programs, and strategies, substance services and treatment, optimal sleep, increasing nature contact can improve overall mental health.
M01 - M02 Precondition
For M01 Mental Health Promotion, WELL ensures that users receive at least two from five options such as education on mental health quarterly, trainings annually, mindfulness program weekly, healthy working hours, a space for relaxation. The project also sends users some form of communication such as annual communication and onboarding to address mental health and well-being benefits with resources.
For M02 Nature and Place, common spaces, rooms, and circulation routes must integrate natural elements related subjects such as natural shape material, plants, water, nature views. The project must designed to provide a celebration of culture and social cognition, celebration of place, integration of art, and human delight that connect to place, by Living Building Challenge 4.0, Core Imperative 19 - Beauty + Biophilia hypothesis topic.
M03 - M11 Optimization
M03 Mental Health Services, offering mental health screening for depression and substance use, providing licensed mental health professional, guidance process for next step for 1 point. Mental health services such as clinical screening, inpatient treatment, outpatient treatment, prescription medication at no cost or subsidy, information on benefits coverage, consultation receives 1 point. Supporting sick leave, shortterm and longterm leave, interpersonal support, adjustment work schedule, adjustment of workplace to quieter area receives 1 point. Mental health recovery by trauma-focus psychotherapy, psychological first aid (PFA), bereavement counseling, information on benefits coverage to additional services receives 1 point.
M04 Mental Health Education, mental health education for regular occupants by managing personal mental health at work, providing in-person or virtually education receives 1 point, and health education for managers by reducing workplace stress, burnout, motivation receives additional 1 point.
M05 Stress Management, develop stress management plan by assessing overwork by more than 48 hours per week, absenteeism, not using paid time off, performance, turnover rates, survey results, improvement of employee stress to change of organization, employee participation receives 2 points.
M06 Restorative Opportunities, supporting healthy working hours by provide minimum 11 consecutive resting hours per day, 24 consecutive hours off per week, 48 hours for those who in shift work, and for eligible employees, minimum 20 days paid time off per year, no work during time off, sick to vacation clearly defined, accrual policy is defined, and for school, do not start earlier than 8:30 am receives 1 point, and additional 1 point for nap allowing and good acoustically separated nap area for 1% of eligible employee at least 30 minutes.
M07 Restorative Spaces, providing break space for users to restorative and encourage relief from fatigue with minimum 7 sqm plus 0.1 sqm per regular users or 186 sqm, with calming adjustable lighting, sound intervention of natural features, thermal control, movable lightweight chars, cushions, natural elements, subdued colors, visual privacy including signage explaining its purpose receives 1 point.
M08 Restorative Programming, for restorative programming such as mindfulness training course, yoga, digital mindfulness offering receives 1 point.
M09 Enhanced Access to Nature, floor plan that at least 75% of workstations have a sight to natural elements winthin 10 meters receives 1 point, and providing outdoor nature access and to one green space or blue space within 200 meter walk distance from boundary, and total green space at least 0.5 hectare receives additional 1 point.
M10 Tobacco Cessation, providing resources and motivation, rewarding, counseling, tobacco prescription for tobacco quitting and limiting of tobacco receives 3 points.
M11 Substance Use Services, education of drug use receives 1 point, and additional 1 point for clinical services.
Community
Estimated 235 million urban families live in low standard housing, leading to poor health outcomes like asthma, infectious disease and cardiovascular. Only 55% of U.S. companies see diversity as a priority, in UK, women earns 80.2% of men's. Spaces usually are not design for diverse needs. Surveying can bring more returns on investment. Fostering civic engagement and espouse can increase employee rentiontion and attraction and financial returns. Design plays critical role to let all users access.
C01 - C04 Precondition
C01 Health and well-being promotion by provides WELL feature guide and regularly communicates to the users.
C02 Integrative design by incorporating all stakeholders to set the health and well-being goals for the project.
C03 Emergency preparedness by implementing emergency management planning and post-occupancy evaluation are also required.
C04 Occupant survey by implement survey program to users.
C05 - C14 Optimization
C05 Enhanced Occupant Survey, total 4 points by using additional survey and analysis for 1 point, using comparison pre and post survey for 1 point, implementing aspirational satisfaction and unmet satisfaction plan for 1 point, focus group activity by interview and evaluate result for 1 point.
C06 Health Services and Benefits, providing employees with a health benefits policy at no cost or subsidized, offering on-demand health services, offering sick leave, supporting vaccinate program receives each 1 point, total 4 points.
C07 Enhanced Health and Well-Being Promotion, promoting culture of health by communications and promotion group receives 1 point. Having at least one dedicated executive-level employee to plan and promote heathy activities receives 1 point.
C08 New Parent Support, offering new parent leave support receives 1, 2, 3 points for paid leave at least 12, 18, 30 weeks. For breastfeeding support, such as break time and giving insulated cooler or refrigerator access receives 1 point. C09 New Mother Support, providing lactation room at least 2.1 x 2.1 m with appropriated elements in the building receives 2 points.
C10 Family Support, childcare support services, offering family leave, offering bereavement support receives each 1 point, total 3 points.
C11 Civic Engagement, promoting community engagement and community space for employees receives each 1 point, total 2 points.
C12 Diversity and Inclusion by creating Diversity, equity, and inclusion (DEI) assessment and action plan, DEI system, DEI hiring practives each receives 1 point, total 3 points.
C13 Accessibility and Universal Design, implementing universal design receives 2 points.
C14 Emergency Resources, providing emergency information or procedures, building notification system, Automated external defibrillator (AEDs), first aid kit, and emergency training for medical emergencies and security team or Cardiopulmonary resuscitation (CPR), first aid, AED usage trainings receives 1 point. Providing opioid pain relieve kit for emergency such as naloxone receives 1 point.
Innovation
I01 - I05 Optimization
This category has no requirement but it can provide additional points such as new intervention for maximum 10 topics, each receives 1 point. If one member of the project team has WELL AP, it automatically receives 1 point. Offering WELL educational tours at least six times per year receives 1 point. If the project commits in any well-being or health program that approved by IWBI and it was completed within three years, it receives 1 point. If the project achieve any green building certification that approved by IWBI, it receives 5 points of rating.
Performance
Scientific research provides information about the standard’s performance. Existing research focuses on the evaluation of indoor environmental quality (IEQ) parameters. The certification requires post-occupancy evaluation, which allows occupants to provide feedback to building owners and management on these IEQ parameters. For buildings with 10 or more occupants, the Occupant Indoor Environmental Quality (IEQ) Survey from the Center for the Built Environment at UC Berkeley (or an approved alternative) is completed by a representative sample of at least 30% of occupants at least once per year. The survey covers the following topics: acoustics, thermal comfort, furnishings, workspace light levels and quality, odors and air quality, cleanliness and maintenance, and layout.
In 2020, researchers analyzed 1,121 post-occupancy evaluation surveys conducted in nine offices, two WELL-certified and seven not WELL-certified. Results of the study were mixed, with higher occupant satisfaction in the WELL-certified buildings for spatial comfort, thermal comfort, noise and privacy, personal control, and workspace comfort, but lower satisfaction for visual comfort and connection to the outside in comparison with non-WELL certified buildings. These findings may be attributable to the types of non-WELL certified buildings used in the comparison, as they may already be high-performance buildings in other regards which do not necessarily satisfy all of the WELL certification’s criteria.
In 2021, another study on surveys compared the results of three rounds of occupant IEQ satisfaction surveys reported by three groups of employees who moved from three non-WELL (two BREEAM and one non-certified) to three WELL-certified office buildings. For two out of the three building pairs, there was a statistically significant increase in building and workspace satisfaction after relocation to WELL buildings. However, for 55% of certification parameters for the three compared cases, there was an insignificant difference upon relocation. Results found higher occupant satisfaction for building cleanliness and furniture but no increase in satisfaction with noise and visual comfort.
Another 2021 study investigated indoor air quality (IAQ) before and after relocation to WELL-certified office buildings. The results indicated there was no significant concentration difference for the majority of measured air pollutants between non-WELL and WELL buildings.
In 2022, researchers conducted a pre- versus post-occupancy evaluation of approximately 1,300 workers transitioning to WELL-certified offices from non-WELL certified offices. Using pre- and post-occupancy surveys, overall satisfaction rates improved from 42% (pre-occupancy) to 70% (post-occupancy) across all parameters. The largest increases in satisfaction were for cleanliness and access to nature, while occupants were most satisfied with maintenance and lighting in WELL-certified offices.
In 2023, researchers analyzed 1,403 post-occupancy evaluation surveys from 14 open-plan offices (10 of which were WELL-certified and four of which were uncertified) in Australia, New Zealand, and Hong Kong. The five offices that achieved the highest satisfaction in interior design, indoor air quality, privacy and connection to the outdoor environment were WELL-certified. No significant differences in health were found between WELL-certified and non-WELL certified buildings as quantified by questions about physical and mental health presented in the post-occupancy evaluation surveys.
In 2024, researchers used a statistical matching approach to compare occupant satisfaction from 3,268 surveys from 20 WELL-certified and 49 LEED-certified buildings. Overall building and workplace satisfaction was found to be high in WELL-certified buildings (94% and 87%). Statistical analysis revealed that there is a 39% higher probability of finding an occupant that is satisfied with the building overall in a WELL-certified building than a LEED-certified building. Although satisfaction was found to be higher in WELL-certified buildings, satisfaction in LEED-certified buildings with the building, workspace, and most IEQ parameters was still relatively high. Temperature and sound privacy in LEED-certified buildings are the only parameters with mean satisfaction values less than “neutral” amongst all studied parameters in LEED- and WELL-certified buildings.
References
Building biology
Building engineering
Environment of the United States
Environmental design
Sustainable building in the United States
Sustainable building rating systems | WELL Building Standard | [
"Engineering"
] | 11,085 | [
"Environmental design",
"Building engineering",
"Civil engineering",
"Design",
"Building biology",
"Architecture"
] |
74,469,739 | https://en.wikipedia.org/wiki/Shirtwaist%20%28architecture%29 | A Shirtwaist house is a variation of the American Four Square architectural style, predominantly built at the beginning of the 20th century. It is characterized by a first floor of exposed brick or limestone and siding-wrapped second and third floors. The style developed and is most commonly found in Kansas City. It is named for the higher-waisted women's fashion popular during that period.
References
Foursquare architecture in the United States
American architectural styles | Shirtwaist (architecture) | [
"Engineering"
] | 91 | [
"Architecture stubs",
"Architecture"
] |
74,470,076 | https://en.wikipedia.org/wiki/Coulomb%20gas | In statistical physics, a Coulomb gas is a many-body system of charged particles interacting under the electrostatic force. It is named after Charles-Augustin de Coulomb, as the force by which the particles interact is also known as the Coulomb force.
The system can be defined in any number of dimensions. While the three-dimensional Coulomb gas is the most experimentally realistic, the best understood is the two-dimensional Coulomb gas. The two-dimensional Coulomb gas is known to be equivalent to the continuum XY model of magnets and the sine-Gordon model (upon taking certain limits) in a physical sense, in that physical observables (correlation functions) calculated in one model can be used to calculate physical observables in another model. This aided the understanding of the BKT transition, and the discoverers earned a Nobel Prize in Physics for their work on this phase transition.
Formulation
The setup starts with considering charged particles in with positions and charges . From electrostatics, the pairwise potential energy between particles labelled by indices is (up to scale factor)
where is the Coulomb kernel or Green's function of the Laplace equation in dimensions, so
The free energy due to these interactions is then (proportional to) , and the partition function is given by integrating over different configurations, that is, the positions of the charged particles.
Coulomb gas in conformal field theory
The two-dimensional Coulomb gas can be used as a framework for describing fields in minimal models. This comes from the similarity of the two-point correlation function of the free boson ,
to the electric potential energy between two unit charges in two dimensions.
See also
Sine-Gordon equation
XY model
References
Statistical mechanics | Coulomb gas | [
"Physics"
] | 362 | [
"Statistical mechanics"
] |
74,471,367 | https://en.wikipedia.org/wiki/Pneumatic%20anti-ice%20system | A pneumatic anti-ice system is a technology that uses air or another gas to prevent ice buildup on ships sailing in icy waters. It is housed below the waterline on the ship's hull. Pneumatic anti-ice systems use compressed air or engine exhaust as the working gas, which is vented overboard through a series of ejectors from bow to amidships. Since the ejectors are located below the waterline or near the keel, the airflow streaming from them forms a water/air curtain along the hull.
History
The concept of a ship anti-icing system in the form of a water-air boundary layer was introduced in 1966 in the USSR. Variants of a heated steam-air system in the waterline area were considered, and the prospects for its use as a thruster to increase maneuverability were studied. The modern form was proposed by Wärtsilä in 1969 and was first installed on Finnish cargo ferry Finncarrier. It was tested in the Baltic Sea in 1970. The first icebreaker on which the pneumatic anti-ice system was installed was the Yermak, built in 1974.
Performance
The adhesion of ice to the hull has thermal and electrostatic aspects. The ongoing processes develop too quickly to warm above-the-waterline ice to the ambient water temperature, as a result of which it freezes or sticks to the hull. Air flushing reduces the contact area of the ice with the hull and increases the temperature by creating an upstream current of warmer water at greater depth, thereby solving the first problem. Another mechanism is the accumulation of an electrostatic charge in the ice when it cracks and breaks. When the state of underwater paint coating of the hull is unsatisfactory, it can become ineffective against preventing ice from sticking.
Referencesiocde
Transport safety
Ice in transportation | Pneumatic anti-ice system | [
"Physics"
] | 374 | [
"Physical systems",
"Transport",
"Ice in transportation",
"Transport safety"
] |
74,472,639 | https://en.wikipedia.org/wiki/Deaf%20flag | The Deaf flag is a flag that symbolises the Deaf community (especially the signing Deaf community), and is used as a form of visibility for a socio-cultural minority that is often discriminated against in various areas.
The flag was designed by the French Deafblind artist Arnaud Balard. It depicts a large open turquoise hand on another yellow hand (of which only the profile around the turquoise hand is visible). The tips of the fingers are outside the flag, so that the fingers "stretch out" indefinitely. The background colour is navy blue.
Symbolism
There are several different symbols that are included in the flag (based on what is indicated by its creator):
The hands represent the signing Deaf community and Sign language.
The infinite fingers allude to the projection of the use of Sign language in the world, with more than 200 existing Sign Languages. The fingers also symbolise the connection with the five continents (in order from top to bottom): Europe, the Americas, Asia, Oceania and Africa.
The colour turquoise is the world color of Sign language, Deaf culture, and the signing Deaf community (Deaf, Deafblind, CODA, Sign Language interpreters, family members).
The colour yellow symbolizes light, life, the awakened mind, coexistence.
The colour navy blue (dark blue) symbolises planet Earth, humanity, and is the color adopted to represent deafness (represented by a blue ribbon). In this way, non-signing Deaf and Deafblind people (oralists) would be included.
The design aims for the flag to be a symbol of openness, inclusiveness and union, rather than isolation or segregation.
History
At the beginning of the 21st century, the World Federation of the Deaf initiated a process to define the Deaf flag.
The Swedish proposal
In 2009, during the Congress of the Swedish Confederation of the Deaf in Leksand, the Swedish National Association of the Deaf (, SDR) was commissioned to present a flag at the 16th World Congress of the World Federation of the Deaf, held from 18 to 24 July 2011 in Durban (South Africa).
At the XVIII General Assembly of the World Federation of the Deaf, held in Durban on 16 and 17 July 2011, the Swedish National Association of the Deaf made a motion for the recognition of a flag representing the Deaf community. Sweden proposed an abstract flag made up of different vertical stripes of different widths, in turquoise and different shades of blue, and a white stripe. This flag represents the five continents (by the five colours of the flag) as well as the sky and water (symbolised by blue) and the Deaf (by turquoise). The Swedish National Association of the Deaf proposed that the income generated by the flag should go to the World Federation of the Deaf.
The idea of having a Deaf flag was largely accepted by the ordinary members (consisting of a national Deaf organisation), but the World Federation of the Deaf postponed the discussion on the design of the flag and its position on supporting the use of the flag proposed by Sweden to the next board meeting, to be held in Norway in November 2011. In the end, no position was taken.
There were many opinions against the design of the Swedish flag, various controversies and parodies on social networks, comparing it to pyjamas, a shower curtain or a barcode.
The World Federation of the Deaf decided to postpone the issue to the II International Conference of the World Federation of the Deaf held in Sydney (Australia) from 16 to 20 October 2013. In the corresponding vote, an absolute majority was not reached, so the proposal was rejected with the following results:
Yes: 21 votes.
No: 11 votes.
The French proposal
In March 2013, French Deafblind artist (with Usher syndrome) Arnaud Balard designed a flag symbolising Sign Language, which he calls the "Deaf and Sign Union Flag" or, in its shorter version, "Deaf Union Flag" or "Sign Union Flag" (preferred by a large part of the Deaf community because it includes the term "sign", which identifies that community, and because it is inclusive of all Sign Language users; instead of the term "Deaf", which is often understood and used as "disease"). Before designing the flag, he spent two years studying the various existing flags and learning vexillology.
The sign given by the flag designer himself is configured as follows:
dominant hand stretched out, fingers spread, palm facing the signer.
non-dominant hand with only the index finger extended, the tip of which rests on the inside of the wrist of the dominant hand.
Arnaud Balard registered and protected his design with the INPI () in France before publicly displaying his flag. He then registered his design for international protection with the WIPO (World Intellectual Property Organisation).
On , the "Sign Union Flag" was first displayed during the first ASL (American Sign Language) and Deaf Pride parade in Washington D.C., and was used by Audism Free America.
On , the French National Federation of the Deaf (, FNSF), one of the ordinary members of the World Federation of the Deaf, recognised and approved the flag designed by Balard.
During the XIX General Assembly of the World Federation of the Deaf held in Istanbul (Turkey) on 26 and 27 July 2015, the French National Federation of the Deaf presented the flag designed by Arnaud Balard to propose its recognition as a Deaf flag for international use. After voting, the proposal was rejected with the following results:
Yes: 32 votes.
No: 20 votes.
Abstention: 12.
As the absolute majority in favour (33 votes) required to approve the proposal was not reached, the proposal was rejected.
One of the reasons for the lack of support for the French proposal was that the World Federation of the Deaf would not have exclusive rights to the flag.
Recognised by the Deaf community, this flag has been displayed on various French official buildings (for example, in 2016 in front of Montpellier City Hall, in 2019 on the façade of Poitiers City Hall, at the Espace Tuilerie of Montchanin, or on the esplanade in front of Massy City Hall), and distributed in several countries, including the United States, Italy, Morocco, Scotland and Colombia.
Approval by the World Federation of the Deaf
At the 2015 General Assembly, following the vote (where the votes in favour did not exceed an absolute majority), the World Federation of the Deaf established a "Deaf Flag Committee" consisting of five ordinary members: France, Iran, Nepal, the Russian Federation, and Sweden. The objective was to select one or more design proposals for the Deaf flag to be presented and voted on by the ordinary members of the World Federation of the Deaf at the XX General Assembly in Paris (France) in 2019.
In January 2018, the committee, with the support of the board of the World Federation of the Deaf, called for graphic designers to join the Deaf Flag Design Review Committee (candidates must be nominated by an ordinary member).
In December 2018, the World Federation of the Deaf launched a call for design proposals for a Deaf flag. The deadline for submitting designs was .
In addition to the Sign Union Flag, several proposals for flag designs were submitted for a vote in July 2019.
At the XX General Assembly held in Paris (France) in July 2019, the representatives of the ordinary members of the World Federation of the Deaf debated France's motion for a deaf flag, but the proposal for a deaf flag was rejected with the following voting results:
Yes: 31 votes.
No: 47 votes.
Having failed to approve a deaf flag, a particular flag was no longer voted on.
Although the issue of the Deaf flag was raised at the General Assemblies in 2011, 2015 and 2019, without any of the proposed designs being adopted, the Board of the World Federation of the Deaf decides to reopen the process: in November 2022, the World Federation of the Deaf launches a call for design proposals for a Deaf flag, to be presented and voted on at the XXI General Assembly in Jeju Island (South Korea). Participation is only allowed through national organisations of deaf people that are members of the World Federation of the Deaf, and the deadline for submitting designs is the .
On the , during the XXI General Assembly of the World Federation of the Deaf, to be held on 9–10 July 2023 on Jeju Island (South Korea), the "approval of the idea of having a deaf flag" was put to a vote, with the following results:
Yes: 54 votes.
No: 12 votes.
The vote was 81.82% in favour of having a Deaf flag.
The flag proposals received from three ordinary members of the World Federation of the Deaf were then presented, discussed and voted on: Lebanon, Russia, and France.
The proposal by the Lebanese Federation of the Deaf (, LFD) consists of two hands, a blue hand on a white hand (representing different cultures and symbolising Sign language and the Deaf signing community), two white brackets, one on each side (symbolising a circle around the Deaf community, which is interconnected and a small world), and a blue background.
The proposal of the Russian Society of the Deaf () consisted of two palms open from the centre, one turquoise and the other blue (symbolising Sign language), both surrounded by a golden outline. The background of the blue hand is turquoise and the background of the turquoise hand is blue.
The voting for the "selection of the design of a Deaf flag" had the following results:
France: 25 votes.
Lebanon: 23 votes.
Russia: 17 votes.
A second vote was taken, with the following results:
France: 36 votes.
Lebanon: 31 votes.
The French proposal was finally approved as the new Deaf flag and a debate ensued as to what the flag should be called: Deaf flag or Sign Union flag. The name Deaf flag was chosen as the other option had little support.
Before the flag vote, there was a controversy over the resemblance of the Russian flag's design to that of the French flag.
Nepal also submitted a flag proposal, but it was rejected as it failed to meet the submission deadlines.
References
External links
Arnaud Balard's website
Official website of the FNSF – Fédération Nationale des Sourds de France ("National Federation of the Deaf of France")
Official website of the WFD – World Federation of the Deaf, in English with translation into other languages
Official website of the SDR – Sveriges Dövas Riksförbund ("Swedish National Association of the Deaf")
Deaf culture
Flags
Flags introduced in 2023
Flags introduced in 2014 | Deaf flag | [
"Mathematics"
] | 2,173 | [
"Symbols",
"Flags"
] |
74,473,135 | https://en.wikipedia.org/wiki/Takao%20Hayashi | Takao Hayashi (born 1949) is a Japanese mathematics educator, historian of mathematics specializing in Indian mathematics. Hayashi was born in Niigata, Japan. He obtained Bachelor of Science degree form Tohoku University, Sendai, Japan in 1974, Master of Arts degree from Tohuku University, Sendai, Japan in 1976 and a postgraduate degree from Kyoto University, Japan in 1979. He secured the Doctor of Philosophy degree from Brown University, USA in 1985 under the guidance of David Pingree.
He was a researcher at Mehta Research Institute for Mathematics and Mathematical Physics, Allahabad, India during 1982–1983, a lecturer at Kyoto Women's College during 1985–1987. He joined Doshisha University, Kyoto as a lecturer in history of science in 1986 and was promoted as professor in 1995. He has also worked in various universities in Japan in different capacities.
Publications
Hayashi has a large number of research publications relation to the history of Indian mathematics. He has also contributed chapters to several encyclopedic publications. The books he has published include:
The Bakhshali Manuscript: An Ancient Indian Mathematical Treatise, Egbert Forsten Publishing, 1995
(jointly with S. R. Sarma, Takanori Kusuba and Michio Yano), Gaṇitasārakaumudī: The Moonlight of the Essence of Mathematics by Thakkura Pherū, Manohar Publishers and Distributors, 2009
Kuṭṭā̄kāraśiromaṇi of Devarāja: Sanskrit Text with English Translation, Indian National Science Academy, 2012
Gaṇitamañjarī of Gaṇeśa, Indian National Science Academy, 2013
(jointly with Clemency Montelle, K. Ramasubramanian) Bhāskara-prabhā, Springer Singapore, 2018
Awards/Prizes
The awards and prizes conferred on Hayashi include:
The Salomon Reinach Foundation Prize, Institut de France (2001)
Kuwabara Prize, the History of Mathematics Society of Japan (2005)
Publication Prize, Mathematical Society of Japan (2005)
References
1949 births
Living people
Historians of astronomy
Historians of mathematics
Indian mathematics
Historians of India
Japanese expatriates in India
Japanese Indologists | Takao Hayashi | [
"Astronomy"
] | 439 | [
"People associated with astronomy",
"Historians of astronomy",
"History of astronomy"
] |
74,473,174 | https://en.wikipedia.org/wiki/Chinese%20character%20components | In Written Chinese, components () are building blocks of characters, composed of strokes.
In most cases, a component consists of more than one stroke, and is smaller than the whole of the character. For example, the character consists of two components: and . These can be further decomposed: can be analyzed as the sequence of strokes , and as the sequence .
There are two methods for Chinese character component analysis, hierarchical dividing and plane dividing. Hierarchical dividing separates layer by layer from larger to smaller components, and finally gets the primitive components. Plane dividing separates out the primitive components at one time.
The structure of a Chinese character is the pattern or rule in which the character is formed by its (first level) components. Chinese character structures include single-component structure, left-right structure, up-down structure and surrounding structure.
Analysis
Chinese characters may be analyzed in terms of smaller components. This analysis is generally based on graphical forms, without considering aspects like pronunciation and meaning.
Component analysis is very helpful for learning Chinese characters. For example:
→+
→+
→+
Through component analysis, one may learn characters in an easier way. If a student learns first, the knowledge will help with the learning or review of , , and . Obviously, learning by component analysis is much more efficient than learning by analyzing each character to strokes. Component analysis is also used in Chinese character encoding for computer input.
There are two methods for Chinese character dividing, hierarchical dividing and plane dividing. Hierarchical dividing separates layer by layer from large to small components, and finally gets the primitive components. Plane dividing separates out the primitive components at one time. Hierarchical dividing can display the external structure of Chinese characters, while plane splitting can be regarded as omitting the higher splitting levels, and directly writing out the final separating result of primitive components.
Rules for division
The rules for hierarchical dividing include:
The separation space ditch/gap () is an obvious boundary, where the character (or bigger component) is split into (smaller) components.
If there is only one separation ditch, split into two components along the separation ditch. For example: →+, →+.
When there is more than one separation ditch, divide along the longer one first. For example: → + →+, to get the hierarchical structure of ((+)+) with two layers of components.
When several separation ditches are parallel and equal in length, divide along all of them. For example: →++.
Intersecting stroke groups are not divided, for example, and are primitive components.
The lower bound of dividing is generally greater than single strokes, and components with only two strokes, such as "", are not to be separated.
Hierarchical analysis should conform to the basic structure of Chinese characters. For example: the outermost layer of "" is in a left-right structure, so the left and right separation is employed first: →+, followed by the inside-outside division (→+), although the latter's L-shaped separation ditch may be longer.
A character containing multi-level components are divided from larger to smaller sizes to generate first-level components, second-level components, third-level components, etc.
An example
The hierarchical analysis of character in (1) bracketed representation:
(((+(+))+(⿱)(+(+(+))))+), 5 layers of components.
or in tree structure:
/ \
/ \
(⿱)
/ \ / \
/ \ / \
/ \
The level to which a Chinese character is to be analyzed or divided depends on actual applications.
In plane analysis, only components on the tree-leaves are presented, i.e.,
: ,,,,,,,.
Analysis data of the Cihai
The following is the analysis data of Cihai (), with a character set of 16,339 traditional and simplified Chinese characters.
In most cases, a component is larger than a stroke and smaller than the whole character (combines with some other components to form the character). The condition for a single stroke to be a component is: occupies a relatively independent location usually occupied by a multiple-stroke component in a character. For example: the top stroke in character , the bottom in , the left in , the right ㇟ in , the central ㇔ in , and the outer ㇆ in . In the special cases of one-stroke characters, such as and , a stroke is a component and is a character.
Classification of components
Character components and non-character components
A component that can independently form a character is a character component, or a component of independent character formation (). For example, component formed character independently, and is a component in characters , and ; and component is also a character by itself, and a component in , and .
A component that can not independently form a character is a non-character component, or a component of dependent character formation (). For example, component in character , and ; and component in , and . Neither nor is a character in modern Chinese.
Primitive components and Compound components
A component that cannot be (further) divided into smaller components by the rules is a primitive component, or basic component (, ). Primitive components are the final-level components of hierarchical dividing. For example, components and in character , and in character .
A component composed of two or more primitive components is a compound component (). For example, component in character , and , and component in , and .
Hierarchy of components
A component divided out at the first level is called a level-one component, a component divided out at the second level is called a level-two component, and so on. A component divided out at the final level is called a final-level component, i.e., primitive component. For example, in the example of character ,
/ \
(level-one components)
/ \
(⿱) (level-two components)
/ \ / \
(level-three components)
/ \ / \
(level-four components)
/ \
(level-five components)
where the leaf components , , , , , , and are final-level components or primitive components.
Single-stroke components and multi-stroke components
A component formed by one stroke is called a single-stroke component. For example,
stroke in character
stroke ㇑ in character
stroke ㇓ in character
stroke ㇔ in character
stroke ㇆ in character .
A component formed by more than one stroke is called a multi-stroke component. For example,
component in character , in character , and of .
Primitive components
Among the 16,339 traditional, simplified and unsimplified characters in Cihai, there are 675 primitive components; among the 11,834 characters excluding the simplified traditional characters, there are 648 primitive components.
In Chinese Character Information Dictionary, among the 7,785 China Mainland standard characters, a total of 623 primitive components have been divided out.
(Divided from 11,834 simplified and unsimplified characters from Cihai).
Component standards
Chinese character components are widely used in Chinese character keyboard encoding input methods. Different encoding input methods have different ways for component separation. Therefore, it is necessary to formulate norms or standards related to Chinese character components.
"Chinese Character Component Standard of GB13000.1 Character Set for Information Processing" (GB13000.1) is a standard released on February 1, 1997, by the National Language Commission of China. It includes a "List of Chinese Character Primitive Components". The list contains 560 primitive components. All the 20,902 CJK Chinese characters in the GB13000.1 character set can be formed with these components. This standard is mainly for Chinese information processing.
Another important standard is the " Specification of Common Modern Chinese Character Components and Component Names" () formulated by the National Language Commission in 2009. It includes a list of 514 primitive components of commonly-used characters and component names. This standard is mainly for Chinese character education and dictionary collation.
Component naming
The rules for component naming include the following:
If the component is a character, then call it by this character, for example: (kǒu) and (tǔ). If the character has more than one sounds, then use the more common one, such as: component "" is called zhōng, not zhòng.
If the component is not a character, then if it has a name, then use the existing name. For example, (tí shǒu, ) and (bǎo gài, ). If the component has more than one name, then use the name commonly used, for example, is rather called shuāng lì rén () than shuāngrén páng ().
For a component without a name, a colloquial and reasonable name should be determined. One way is to refer to the component by its position in common characters. For example: "the head of character " (, ), "the frame of character " (, ).
Chinese character structures
The structure of a Chinese character is the pattern or rule in which the character is formed by its (first level) components. Chinese character structures include
Single-component structure: The character is formed by a single primitive component, such as , and .
Left-right structure (⿰): The character is formed by a component on the left and another one on the right, such as , and .
Left-middle-right structure (⿲): The character is formed by a component on the left, a component on the right and a component in the middle, such as , and .
Up-down structure (⿱): The character is formed by a component above another component, such as , and .
Up-middle-down structure (⿳): The character is formed by a component at the top, a component at the bottom and a component in the middle, such as , and .
Complete-surrounding (⿴ ): such as , and .
Left-top-right-surrounding (⿵): such as , and .
Top-left-bottom-surrounding (⿷): such as , and .
Left-bottom-right surrounding (⿶): such as , and .
Top-left surrounding (⿸): such as , and .
Top-right surrounding (⿹): such as , and .
Left-bottom surrounding (⿺): such as , and .
overlapping (⿻), or multi-frame surrounding: such as , , , .
The principles of Chinese character first-level structure analysis can be extended to other levels. For example, character is in left-right structure, where the left component is in up-down structure.
Deformation of components
Sometimes in order to make the glyph more beautiful and reasonable in structure, a component may need to be changed in form according to the character environment.
The deformation of the components can be made in two ways:
Change the shape of individual strokes.
The entire component is flattened or narrowed.
Stroke deformation within a component
Stroke deformation includes the following situations:
When the bottom stroke of a left component is ㇐ (heng, horizontal) or ㇐ intersected with ㇑ (shu, vertical), the ㇐ is usually changed to ㇀ (ti ). For example: , exception: .
When "" is used as the left component, the last stroke ㇑(shu) should be changed to ㇓(pie). For example: "".
If the last stroke of a component is ㇏ (na), and the component is on the left side or in a surrounding structure, then ㇏ often needs to be changed to ㇔ (dian, dot). Such as: "".
When adjacent strokes have two or more (parallel) ㇏ (na), generally only keep one ㇏, and change the rest to ㇔ (dots). Such as: "".
When component "" is on another component, the hook should be removed. For example: "".
When "" is on the left side of other components, the horizontal bending hook is often changed to lifting. For example: "".
When the last stroke of the left radical is a ㇟(vertical bend hook), it is often changed to a ㇙ (vertical lift). For example: "".
When "" (hand) is used on the left side, the vertical hook may be changed to ㇓ (pie). For example: "".
Narrowing or flattening of components
The narrowing or flattening of components is to make the structure of the whole character harmonious and well-proportioned. Take "" (dog) as an example:
In the upper and lower structures, to be flattened. For example: "".
In the left and right structure, to be narrowed. For example: "".
Pianpang and radicals
Pianpangs () and radicals () are components.
Originally, the left side of a combined Chinese character was called pian, and the right side was called pang. Nowadays, it is customary to refer to the left and right, upper and lower, outer and inner parts of combined characters as pianpangs. Therefore, the pianpang analysis of combined characters is similar to the first-level component analysis.
Piangpang generally carry sound or meaning information. They are called "sound side" (also called "sound symbol") and "meaning side" (also called "meaning symbol") respectively.
Radicals are components used for sorting and retrieving Chinese characters. According to the glyph structure of Chinese characters, the common components of a group of characters are taken as the basis for character sorting and searching. And these components are called radicals.
In pictophonetic characters, the radicals are mostly pianpangs representing the meaning.
Component optimization
Hu Qiaomu said:
"The (primitive) components of Chinese characters should be reduced, and the components of Chinese characters should be made independent characters as many as possible; those that cannot be characters should be universal and easy to say. This may be more important than reducing the number of strokes and characters.
Some simplified characters have added new components of Chinese characters. For example, '' and so on. Although the traditional character has more strokes, it is very clear to say: '+ '.
When we simplify Chinese characters, we should avoid new unspeakable and uncommon components. "
Components are important structural units of Chinese characters. Optimizing the components of Chinese characters to make them more concise, standardized, and easy to learn and use is an important task for Chinese character optimization, and there is a long way to go.
See also
Chinese character strokes
Chinese whole characters
Chinese character structures
Modern Chinese characters
:zh:漢字部件
Notes
References
Citations
Works cited | Chinese character components | [
"Technology"
] | 2,984 | [
"Components",
"Chinese character components"
] |
74,473,339 | https://en.wikipedia.org/wiki/%C3%87akmak%20Line | The Çakmak Line () is a defense line established by Turkey, first on the Kırklareli-Edirne line and then in Çatalca in order to deter and counter any attack by the Germans on the Eastern Thrace border. It was built in anticipation of the outbreak of World War II. It stretched from the Sea of Marmara to the Black Sea.
History
The Chief of the General Staff, Marshal Fevzi Çakmak, used the French Maginot Line as an example, and prepared plans for a fixed defensive line constructed of concrete and steel in Thrace. Fevzi Çakmak wanted to give this line of defense his last name. However, President Mustafa Kemal Atatürk opposed his plan and said:War is always fought on the ground and it is won or lost on the ground. No matter how powerful the Çakmak Line is, its lifespan is as short as that of a battle. I do not bury my people's money under the ground for a whim. After the death of Atatürk on November 10, 1938, İsmet İnönü became the president. During his presidency, and in anticipation of the outbreak of World War II, the General Staff established the Çakmak Line, as proposed by Çakmak, in the north of Kırklareli in order to resist any attack that might come from the Balkans on the Thrace border. In February 1941, the Germans invaded Bulgaria and reached the Turkish border. Thereupon, it was decided to draw the line to Çatalca. It was considered doubtful that this plan would be successful in the face of modern tactics used by the Germans.
The Çakmak Line was built in two lines starting from Terkos Lake (Durusu) to Büyükçekmece. On these lines, there are military bunkers, some of which are large and some of which are small. This position is connected to each other with wall wire and iron barriers. Çakmak Line Construction could not progress due to lack of cement and iron. Only 380,000 tons of cement could be produced annually, and it was found in these factories in places that could be easily destroyed.
After Nazi Germany invaded Greece, the Çakmak Line lost its defensive function, as it was arranged against attacks from Bulgaria, whereas Germany could now invade Turkey via Western Thrace. If the enemy forces attacked directly from the lower part of the Meriç river, İsmet İnönü had the Çakmak Line evacuated and pulled the army to the Çatalca line, since the Çakmak Line, which stretched along the northern border of Thrace, would cease to meet with the back part. Many soldiers lost their lives in the Cakmak Line due to the cold. In Çatalca, on the other hand, the people in the villages suffered and some of them even migrated to Anatolia. Today, the bunkers belonging to the Çakmak Line can still be seen in Eastern Thrace.
References
Turkey in World War II
World War II defensive lines
Military installations of Turkey
Eastern Thrace | Çakmak Line | [
"Engineering"
] | 631 | [
"World War II defensive lines",
"Fortification lines"
] |
74,473,344 | https://en.wikipedia.org/wiki/Fuh-Sheng%20Shieu | Fuh-Sheng Shieu (; born 22 August 1959) is a Taiwanese academic administrator and politician who served as the Minister of Environment of Taiwan from 22 August 2023 to 20 May 2024.
Education and academic career
Shieu earned a doctorate in materials science and engineering from Cornell University in 1990, advised by Steve Sass. He worked for the Dow Chemical Company in Michigan for three years, then returned to Taiwan. Shieu began teaching at National Chung Hsing University in 1993, and successively led the College of Engineering and Office of Research and Development at NCHU prior to replacing Der-Tsai Lee as university president. Shieu assumed the NCHU presidency on 1 August 2015. During his presidential tenure, the university started a breakfast program to entice its students to awaken earlier, and established the first Academy of Circular Economy in Taiwan. Shieu is the founding leader of the National University System of Taiwan.
Political career
Shieu was named the head of the Ministry of Environment in July 2023. He took office on 22 August 2023. In April 2024, Shieu confirmed that he would step down from his governmental position after the incoming William Lai administration had taken office.
Honors
Shieu is a fellow of the Institution of Engineering and Technology, the Institute of Materials, Minerals and Mining, and the Australian Institution of Energy.
Personal life
Fuh-Sheng Shieu is married to Chi Mei-lih.
Notes
References
1959 births
Living people
Cornell University alumni
Presidents of universities and colleges in Taiwan
Ministers of environment of Taiwan
Academic staff of the National Chung Hsing University
Taiwanese expatriates in the United States
Fellows of the Institute of Materials, Minerals and Mining
Taiwanese university and college faculty deans
Fellows of the Institution of Engineering and Technology
Dow Chemical Company employees | Fuh-Sheng Shieu | [
"Engineering"
] | 355 | [
"Institution of Engineering and Technology",
"Fellows of the Institution of Engineering and Technology"
] |
74,475,802 | https://en.wikipedia.org/wiki/Harparskog%20Line | Harparskog Line was the main defense station and military fortification built by the Finns after the Winter War of 1940–1941 on the border of Hanko.
Details
This line was not fully completed at the beginning of the Continuation War and remained unused at the Battle of Hanko. But the existence of this defense line made it possible to transfer troops from the Hanko area to the east in July–August 1941. Major Komola was responsible for the construction of this line. The line ran from Westerwick in Wetlax Brumarrow west to east south of Cerlanted Island to Bagu District.
By the end of May 1941, 46 concrete shelters on the Harparskog line were ready for operation and 141 trenches were under construction. There were also 46 ready cannons, 13 cannons under construction and 113 machine gun positions under construction. A total of 57.8 km of barbed wire barriers and 3.8 km of tank barriers were built in this line.
The structures of the Harparskog line are largely preserved. The monument to the line is located at the place where Carl Gustav Emil Mannerheim crossed on 15 December 1941. The name of this line is taken from the village it passes through.
References
Forts in Finland
History of Uusimaa
World War II defensive lines | Harparskog Line | [
"Engineering"
] | 264 | [
"World War II defensive lines",
"Fortification lines"
] |
75,765,840 | https://en.wikipedia.org/wiki/Cothenius%20Medal | Cothenius Medal is a medal awarded by the German National Academy of Sciences Leopoldina (known as the Leopoldina) for outstanding scientific achievement during the life of the awardee. The medal was created to honour Christian Andreas Cothenius, who was the personal physician to Frederick the Great. In 1743, Cothenius became a fellow of the Leopoldina, later president of the learned society that had been created by Emperor Leopold I. When Cothenius died, he left a sum of money in his will to the society with the condition that the interest on the money should be used to award a gold medal, every two years by answering a question in medicine whereby some new truth could be established. Up until 1864, the award came with a prize but was then converted into an award for the promotion of research over the whole period of a person's life. Each medal bears the Latin inscription "Praemium virtutis salutem mortalium provehentibus sancitum" (Created in recognition of the ability of those who promote the good of mortals).
Cothenius Medal awardees, 1959–2023
Cothenius Medal awardees, 1864–1953
Cothenius Medal awardees, 1792–1861
References
Cothenius Medal
Awards established in 1792
Biology awards
Chemistry awards
Physics awards
1743 in science
Geology awards | Cothenius Medal | [
"Technology"
] | 269 | [
"Biology awards",
"Cothenius Medal",
"Chemistry awards",
"Science and technology awards",
"Physics awards"
] |
75,766,808 | https://en.wikipedia.org/wiki/Penoxsulam | Penoxsulam is sulfonamide and triazolopyrimidine herbicide that acts as an acetolactate synthase inhibitor. It is primarily used for rice production.
References
Herbicides
Triazolopyrimidines
Sulfonamides
Methoxy compounds
Trifluoromethyl compounds | Penoxsulam | [
"Chemistry",
"Biology"
] | 67 | [
"Herbicides",
"Biocides"
] |
75,767,608 | https://en.wikipedia.org/wiki/Sulcus%20primigenius | The (Latin for "initial furrow") was the ancient Roman ritual of plowing the boundary of a new cityparticularly formal coloniesprior to distributing its lots or erecting its walls. The Romans considered the ritual extremely ancient, believing their own founder Romulus had introduced it from the Etruscans, who had also fortified most of their cities. The ritual had the function of rendering the course of the city wall sacrosanct but, owing to the necessity of some profane traffic such as the removal of corpses to graveyards, the city gates were left exempted from the ritual.
Ritual
According to surviving classical sources, the needed to occur on an auspicious day of the Roman calendar, further confirmed by augury or similar consultation of omens. The magistrate or other official in charge of the ceremony personally set a bronze plowshare on a wooden ard, which was then attached to a yoked pair of cattle. All literary sources state that the team should consist of a cow on the left and a bull on the right, driven counterclockwise so that the cow was to the inside and the bull to outside, although surviving numismatic evidence appears to show only bulls or standard oxen instead. The ritual was solemn enough that it needed to be performed togate and with covered head () but, as it required the use of both hands, the magistrate's toga was worn wrapped tightly and cinched in Gabine style. In this manner, the magistrate whipped the cattle around the entire course of the future city walls. All of the clods of earth raised by the plow were supposed to fall to the inside, which was accomplished by keeping the plow crooked and by men following the magistrate and plow. This procedure simultaneously established an initial city wall () from the clods and its protective ditch () from the furrow itself. This course was considered sacred and inviolable, which required that the plow be lifted across the locations of the future city gates so that it would be religiously permissible to enter and leave the town, particularly with profane cargo such as corpses or waste. The cattle were sacrificed at the end of the procedure. The city wall was subsequently raised over the earth beside the furrow, whose inner boundary set the outer limits for subsequent auspices performed by the city.
In Latin, the verb used to describe performing this ritual was ("to trace"). The Romans considered it an inheritance from Etruscan religion, meaning that it was presumably included among the sections on the founding of cities in the now-lost Books of Ritual (). For the Romans, the was the essential establishment of a city to the point that Roman law held as late as Justinian that the furrow of the plow was the formal delimitation of a city's territory. In like manner, plows were used to deconsecrate walls, undoing any former ritual and removing any religious stigma from their destruction.
Rome
Plutarch relates the Roman legend that Romulus was guided in the foundation of Rome by Etruscan priests. The daythe 30th of an early Roman month, a new moonwas supposedly marked by a conjunction of the sun and moon producing an eclipse, although modern scholars consider this a mistaken backward application of celestial tables of Plutarch's time and no actual eclipse occurred within a century of the suggested date. After creating a circular pit or trench (), Romulus had the city's initial settlers throw soil from their homelands into it along with representative sacrifices of the necessities and luxuries of settled life. Plutarch places this in a valley at the Comitium, although most accounts placed Romulus's settlement on the Palatine Hill. Romulus then plowed the , establishing Rome's quadrangular first walls and initial sacred boundary. In his discussion of Claudius's later expansion of the pomerium, Tacitus relates that his own belief was that Romulus's furrow and Rome's initial boundarythough unmarked by the 1st century when he was writinghad included the Altar of Hercules in the Forum Boarium and then ran east along the base of the Palatine to the Altar of Consus before turning north to include the Curia Hostilia and the shrine of the Lares Praestites at the Regia and ending at the Forum Romanum; this is only two sides of the course butsince he ascribes the inclusion of the Forum and the Capitol to Titus Tatiusit presumably would have run along the other two sides of the Palatine. (Lanciani notes several problems with this proposed course, which in the archaic period would have probably run through marshland.) Dionysius of Halicarnassus, possibly overstating the point, states that Romulus's furrow was continuous rather than leaving the necessary spaces at the wall's gates. Dionysius then states that Romulus offered sacrifices and provided public games. Before the settlers could enter the city and build their houses, he lit fires before their tents, which they leapt over to expiate any previous guilt or offense and to purify themselves. They then offered their own sacrifices, each as well as they were able. (Against this, Plutarch held the Parilia festival was long kept without any sacrifice at all to commemorate the sanctity of the event of the city's founding.) When the city's walls were later expanded by Rome's kings and under the Republic, the formal sacred boundary was marked with boundary stones. Varro noted the same had been done at Aricia.
Other settlements
The Romans thought many of the Latin towns had been established by the same ritual and used it for all of their formal colonies. Under influence from the Etruscans and Greeks, such colonies were typically established with Hippodamian grids or similar centuriation, meaning their walls' gates were typically placed at each end of major thoroughfares known as and . The walls frequently varied from perfect squares or rectangles, however, owing to local topography.
The was a common reverse type for coins issued by the colonies, often appearing with their first issues but sometimes continuing in use for centuries thereafter. The typical form was to show a magistrate goading a team of oxen with a raised whip. The design was sometimes localized through the inclusion of legionary vexillas or adjusting the cattle to reflect the size of local livestock. Nearly 30 examples of such issues are known, ranging from Iulia Constantia Zilil in Mauretania to Rhesaina in Mesopotamia.
Literature
In Vergil's Aeneid, the hero Aeneas sees the Carthaginians following the ritual and later lays out Lavinium in Italy with his own plow.
As noted by Varro, Pomponius, Isidore, and St. Augustine, the Romans generally derived the etymology of ("city") itself from ("sphere") with regard to the ritual furrow established at its creation.
See also
Agriculture in ancient Rome
Ancient Roman defensive walls
Glossary of Roman religion
References
Citations
Bibliography
Ancient sources
.
, now lost but cited in Servius and Isidore.
.
, an epitome of Flaccus's now lost De Verborum Significatione.
.
.
.
.
, now lost but cited in Tribonian & al.
.
.
.
.
, Books I & V.
Modern sources
.
.
.
.
.
Ancient Roman city planning
Roman agriculture
Roman law
Topography of the ancient city of Rome
Ancient Roman religious practices
Ancient Roman architecture
Ancient Roman geography
Urban geography
Urban design
City founding
Religious rituals
Animal festival or ritual
State ritual and ceremonies
Rituals attending construction | Sulcus primigenius | [
"Engineering"
] | 1,568 | [
"Construction",
"Rituals attending construction"
] |
75,767,733 | https://en.wikipedia.org/wiki/Thea%20Energy | Thea Energy is an American fusion power company founded in 2022 after a spin-out from the Princeton Plasma Physics Laboratory (PPPL). Its original name was Princeton Stellarators, Inc (PSI). Thea Energy's approach to commercial fusion is based on the stellarator approach using a unique set of all-planar electromagnetic coils. This all-planar coil approach was developed by PPPL and licensed by Thea Energy.
History
Thea Energy was founded in 2022 as Princeton Stellarators, Inc, based on technology licensed from PPPL.
Thea Energy received two United States Department of Energy INFUSE awards in 2022 and one in 2023.
In May 2023, Thea was one of eight companies chosen for the United States Department of Energy Milestone-Based Fusion Development Program.
Approach
Thea Energy's approach is a variant of the stellarator in which the complex, modular electromagnetic coils are replaced by an array of small, simple, planar electromagnetic coils. This approach simplifies the design, allows for precise 3D control of the resultant magnetic field, and allows for increased access for system maintenance.
As an intermediate step towards a fusion power plant, Thea is building Eos, a neutron source based on the same technology. Eos is intended to demonstrate the technology and generate near-term revenue. It is expected to run sub-breakeven with respect to energy, but produce large numbers of neutrons for the creation of radioisotopes such as tritium and medical radioisotopes. The fuel for the neutron source will be deuterium rather than a mixture of deuterium and tritium.
See also
Wendelstein 7-X
Plasma stability
References
External links
Thea Energy presentations and publications page~~
Fusion power companies
Nuclear technology companies | Thea Energy | [
"Engineering"
] | 366 | [
"Nuclear technology companies",
"Engineering companies"
] |
75,768,013 | https://en.wikipedia.org/wiki/Cost-sensitive%20machine%20learning | Cost-sensitive machine learning is an approach within machine learning that considers varying costs associated with different types of errors. This method diverges from traditional approaches by introducing a cost matrix, explicitly specifying the penalties or benefits for each type of prediction error. The inherent difficulty which cost-sensitive machine learning tackles is that minimizing different kinds of classification errors is a multi-objective optimization problem.
Overview
Cost-sensitive machine learning optimizes models based on the specific consequences of misclassifications, making it a valuable tool in various applications. It is especially useful in problems with a high imbalance in class distribution and a high imbalance in associated costs
Cost-sensitive machine learning introduces a scalar cost function in order to find one (of multiple) Pareto optimal points in this multi-objective optimization problem.
Cost Matrix
The cost matrix is a crucial element within cost-sensitive modeling, explicitly defining the costs or benefits associated with different prediction errors in classification tasks. Represented as a table, the matrix aligns true and predicted classes, assigning a cost value to each combination. For instance, in binary classification, it may distinguish costs for false positives and false negatives. The utility of the cost matrix lies in its application to calculate the expected cost or loss. The formula, expressed as a double summation, utilizes joint probabilities:
Here, denotes the joint probability of actual class and predicted class , providing a nuanced measure that considers both the probabilities and associated costs. This approach allows practitioners to fine-tune models based on the specific consequences of misclassifications, adapting to scenarios where the impact of prediction errors varies across classes.
Applications
Fraud Detection
In the realm of data science, particularly in finance, cost-sensitive machine learning is applied to fraud detection. By assigning different costs to false positives and false negatives, models can be fine-tuned to minimize the overall financial impact of misclassifications.
Medical Diagnostics
In healthcare, cost-sensitive machine learning plays a role in medical diagnostics. The approach allows for customization of models based on the potential harm associated with misdiagnoses, ensuring a more patient-centric application of machine learning algorithms.
Challenges
A typical challenge in cost-sensitive machine learning is the reliable determination of the cost matrix which may evolve over time.
Literature
Cost-Sensitive Machine Learning. USA, CRC Press, 2011.
Abhishek, K., Abdelaziz, D. M. (2023). Machine Learning for Imbalanced Data: Tackle Imbalanced Datasets Using Machine Learning and Deep Learning Techniques. (n.p.): Packt Publishing.
References
Machine learning | Cost-sensitive machine learning | [
"Engineering"
] | 540 | [
"Artificial intelligence engineering",
"Machine learning"
] |
75,769,708 | https://en.wikipedia.org/wiki/C44H34O22 | {{DISPLAYTITLE:C44H34O22}}
The molecular formula C44H34O22 may refer to:
Theasinensin A
Theasinensin D | C44H34O22 | [
"Chemistry"
] | 39 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
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