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72,590,787 | https://en.wikipedia.org/wiki/Martha%20Anderson | Martha Carol Anderson is research scientist with the United States Department of Agriculture. She is known for her work in using satellite imagery to track droughts and their impact on crops. In 2022, she was elected a fellow of the American Geophysical Union. In 2024, she was elected a fellow of the National Academy of Engineering.
Education and career
Anderson has a B.A. from Carleton College (1987), and she earned her Ph.D. from the University of Minnesota in 1993. Following her Ph.D., she moved to the University of Wisconsin-Madison where she worked first as a postdoctoral researcher and then as an associate researcher and assistant scientist. In 2005, she moved to the Agricultural Research Service as a research physical scientist.
Research
Anderson conducted her Ph.D. research in the field of observational astrophysics, focusing on the investigation of supernovae. She then changed her research focus to the interactions between soils, plants, and the atmosphere and how this is detected using remote sensing. She uses data from satellites to develop models that are used to predict droughts and soil moisture stress, and the subsequent impacts on crops.
Selected publications
Awards and honors
In 2022, Anderson was elected a fellow of the American Geophysical Union. In 2022, she also received the John Dalton medal from the European Geosciences Union in recognition of her work on "multi-scale thermal remote sensing to evapotranspiration and drought impact assessments."
References
External links
Living people
Carleton College alumni
University of Minnesota alumni
Remote sensing professionals
Hydrologists
United States Department of Agriculture people
Year of birth missing (living people) | Martha Anderson | [
"Environmental_science"
] | 328 | [
"Hydrology",
"Hydrologists"
] |
72,591,228 | https://en.wikipedia.org/wiki/Greta%20Hammarsten | Greta Hammarsten (née Norrbin) (March 22, 1896 – July 17, 1964) was a Swedish medical doctor and a pioneer of clinical chemistry in Scandinavia.
Education and career
Hammarsten was born in the Maria Magdalena parish in Stockholm. She left grammar school early and worked for Skandia from 1914 till 1918. From 1919, she started working as an assistant at the Karolinska Institute, where she stayed until 1927. During this time, she also studied microchemical analysis at the University of Graz in 1924 and chemistry at the Carlsberg Laboratory in Copenhagen from 1927 to 1928 and from 1930 to 1931, where she worked for S. P. L. Sørensen and Kaj Linderstrøm-Lang. She enrolled at Lund University in 1930 and became a medical licentiate and doctor of medicine in 1940. Her doctoral thesis was titled Eine experimentelle Studie über Calciumoxalat als Steinbildner in den Harnwegen : speziell mit Rücksicht auf die Bedeutung des Magnesiums, in which she examined the formation of kidney stones from calcium oxalate in the urinary tract, also known as renal lithiasis. She was an assistant at Lund University's medical-chemical department between 1930 and 1938. She worked at the medical clinic at Lund University between 1938 and 1939 and as an assistant physician at Hässleby sanatorium in 1940.
Hammarsten was an associate professor in medical and physiological chemistry at Lund University between 1940 and 1941, in clinical chemistry at the Karolinska Institute from 1946 onwards. Hammarsten moved to the Serafimerlasarettet in 1940 and to Södersjukhuset in Stockholm in 1945, where she served as the director of the central laboratory of clinical chemistry . In this role, she oversaw the expansion of the laboratory and made it a hub for scientific activity within the hospital. Her research interests extended beyond kidney stone diseases to include blood and liver diseases, as well as Rheumatoid arthritis. She was also known for her expertise in the field of blood diseases and conducted several experimental physiological studies in collaboration with Swedish and Danish colleagues.
Research
Hammarsten published over 80 papers in physical and physiological chemistry and nutritional physiology. In 1947, Hammarsten published a voluminous guide to clinical chemistry analysis methods (Kliniska laborationsmetoder), which became a standard reference for laboratories in the Nordic countries. This work was updated and expanded in a second edition published in 1955, with contributions from other colleagues. In 1957, an appendix titled "Laboratory Tests" was added to the guide, including chapters on anticoagulation therapy, fluid balance, cystinuria, and B12 analysis.
Personal life
Hammarsten married Swedish physician and pharmacist Einar Hammarsten in 1918; the marriage ended in 1928. She died in the Kungsholm parish in Stockholm. She was buried at the Northern Cemetery outside Stockholm.
References
1964 deaths
1896 births
Burials at Norra begravningsplatsen
Swedish biochemists
University of Graz alumni
Lund University alumni
Academic staff of the Karolinska Institute
Carlsberg Laboratory staff
Women biochemists | Greta Hammarsten | [
"Chemistry"
] | 649 | [
"Biochemists",
"Women biochemists"
] |
72,592,334 | https://en.wikipedia.org/wiki/Collaborative%20combat%20aircraft | Collaborative combat aircraft (CCA) is a US program for unmanned combat air vehicles (UCAVs) that is considered broadly equivalent to a loyal wingman. CCAs are intended to operate in collaborative teams with the next generation of manned combat aircraft, including sixth-generation fighters and bombers such as the Northrop Grumman B-21 Raider. Unlike the conventional UCAVs, the CCA incorporates artificial intelligence (AI), denoted an "autonomy package", increasing its survivability on the battlefield. It is still expected to cost much less than a manned aircraft with similar capabilities. The US Air Force plans to spend more than $8.9 billion on its CCA programs from fiscal years 2025 to 2029, with an additional $661 million planned for fiscal year 2024. The success of the CCA program may lessen the need for additional manned squadrons.
Characteristics
A CCA is a military drone with an onboard AI control system and capability to carry and deliver a significant military weapons load. Its AI system is envisaged as being significantly lighter and lower-cost than a human pilot with their associated life support systems, but offering comparable capability in flying the aircraft and in mission execution.
Role
The principal application is to elevate the role of human pilots to mission commanders, leaving AIs to operate under their tactical control as high-skill operators of relatively low-cost robotic craft.
CCAs can perform other missions as well, as "a sensor, as a shooter, as a weapons carrier, as a cost reducer".
Capabilities
Although a CCA will be a fraction of the cost of a manned fighter, they would not be considered expendable or even vulnerable to attrition. A CCA would have sufficient intelligence and onboard defense systems to survive on the battlefield. US Air Force Secretary Frank Kendall has described them as playing perhaps "100 roles": remotely controlled versions of targeting pods, electronic warfare pods or weapons carriers to provide additional sensors and munitions; to balance affordability and capability.
The price point of a CCA will determine how many types of missions a single airframe can perform, with more expensive designs able to be multirole aircraft, while cheaper designs could be modular to perform different tasks on different days which can afford to be lost in combat. Two increments are planned: increment 1 CCAs will have sensor and targeting systems to focus on carrying additional munitions for manned aircraft; increment 2 CCAs will have greater stealth and autonomy to perform missions including EW, SEAD, and potentially act as decoys. It's possible two distinct solutions could emerge from this stage, one high end and "exquisite" and the other more basic and inexpensive oriented around a single mission. Service officials started out developing the increment 2 CCA as a high-end, stealthy platform, but wargames showing that large numbers of low-end aircraft would be more effective than small numbers of high-end versions in a simulated Pacific conflict influenced them to rethink their approach.
The USAF is seeking CCAs with greater thrust than the current MQ-28 and the XQ-58.
History
The concept of the CCA arose in the early 2000s. CCA programs include the USAF Next Generation Air Dominance (NGAD) program. The US Navy and USAF plan to be able to control the CCAs and NGADs of either service. The CCA is being developed in collaborative fashion by multiple commands of the USAF: MG Heather L. Pringle of the Air Force Research Laboratory (AFRL); MG R. Scott Jobe of Air Combat Command (ACC); LTG Dale R. White, program executive officer (PEO) for fighters and advanced aircraft; and BG Joseph Kunkel, DCS, Plans and Programs. All four generals agreed on the need to put CCAs into the Joint Simulation Environment.
Defense policy expert Heather Penney has identified five key elements for the collaborative development of crewed-uncrewed teaming of autonomous loyal wingmen, remote pilots of unmanned aerial vehicles (UAVs), and pilots flying separately in manned aircraft (also called manned-unmanned teaming).
Create concepts that will maximize the strengths of both CCA and piloted aircraft working as a team.
Include operators in CCA development to ensure they understand how they will perform in the battlespace.
Warfighters must be able to depend on CCA autonomy.
Warfighters must have assured control over CCA in highly dynamic operations.
Human workloads must be manageable.
The Autonomous Core System, Skyborg's autonomy package, was shown to be portable across multiple airframes; this has led Skyborg to become a Program of Record with a Program Executive Officer (PEO) for acquisition. Skyborg will continue to serve as a science and technology platform.
Most UAVs are remotely piloted, but an AI program piloting a collaborative combat aircraft would need a mission commander for crewed-uncrewed teaming. —Heather Penney. In 2020, The Defense Advanced Research Projects Agency (DARPA) AlphaDogfight test program established that AI programs that fly fighter aircraft will overmatch human pilots, to the extent that the AI agents even flew with fine motor control. An autonomy package on the VISTA testbed has demonstrated dogfighting capability. US Air Force Secretary Frank Kendall flew in the X-62A VISTA, which was under AI control. The NGAD is anticipated to use loyal wingmen (CCAs). Air Force Secretary Frank Kendall envisions these uncrewed aircraft as performing parts of a larger mission; CCA development can be conducted in parallel with NGAD development, which has to take into account a larger set of requirements. Up to five autonomous CCAs would operate with an NGAD.
Air Force Research Laboratory (AFRL) will test their Skyborg manned-unmanned programs such as Autonomous Air Combat Operations (AACO), and DARPA will test its Air Combat Evolution (ACE) artificial intelligence program. The System for Autonomous Control of Simulation (SACS) software for human interface is being developed by Calspan.
DARPA's Longshot is an air-launched UAV meant to extend the range of a mission and reduce the risk to manned aircraft, which could then remain at standoff range; if Longshot were to use Air Combat Evolution (ACE), missiles launched from that Longshot could more effectively select targets. On March 6, 2023, DARPA chose General Atomics Aeronautical Systems (GA-ASI) to carry out the design of the air-launched Longshot drone through Critical Design Review (CDR); a LongShot would itself carry an AMRAAM or Sidewinder missile, which greatly extends the range of these missiles. In this way, a Boeing F-15EX Eagle II or similar 4th-generation fighter can greatly increase their survivability, when armed with a LongShot. GA-ASI is developing a core package (Gambit) for the CCA market.
On 9 December 2022, the Air Force Test Pilot School tested its General Dynamics X-62 VISTA, a modified F-16 Fighting Falcon which can fly autonomously, with 2 different AI packages. By 16 December 2022 the VISTA had flown eight sorties using ACE, and six sorties using AACO, at a rate of two sorties per day. Six F-16s from Eglin AFB will be fitted with autonomy agents, to establish the foundation of the Collaborative Combat Aircraft (CCA) program. The CCA lines of effort were:
Developing the Collaborative combat aircraft platform itself,
developing the autonomy package that will fly a CCA, and
figuring out how to organize, train, equip, and supply the CCA program
On 24 January 2024, the US Air Force awarded contracts to five contractor teams led by Anduril, Boeing, General Atomics, Lockheed Martin, and Northrop Grumman for the development of collaborative combat aircraft.
On 24 April 2024, the US Air Force announced that they had eliminated Boeing, Lockheed Martin, and Northrop Grumman from the Increment I competition and that the Anduril Fury and General Atomics Gambit would be moving forward with development. The Air Force expects to make a final decision between the two companies' offerings by 2026. As the CCA program is expected to result in multiple types of aircraft with varying capabilities and costs, all companies are expected to bid again for follow-on Increments.
On 19 September 2024, General Atomics displayed a full-scale model of a CCA. One such CCA version is a 'missile truck', which would augment the capabilities of a crewed/uncrewed mission. Anduril, a competing CCA vendor also displayed a full-scale model.
Funding
A CCA is estimated to cost between one-half and one-quarter as much as $80 million Lockheed Martin F-35 Lightning II; the desired cost is between $25-30 million per airframe. US Air Force Secretary Frank Kendall is aiming for an initial fleet of 1,000 CCAs. As elements of a crewed-uncrewed team, two CCAs could be teamed with an NGAD or F-35, say two for each of the 200 NGAD platforms, and two for each of the 300 F-35s, in order to work out concepts to integrate them into the service, but the full inventory could be twice that size. As of 3 July 2024, the Air Force requested reprogramming an additional $150 million for CCA development in 2024. This is a 40% increase over the $392 million budget previously requested; the FY2025 budget request will reflect an additional increment; the money for NGAD was adjusted appropriately.
The 26th Secretary of the US Air Force listed CCAs among his top seven priorities for the fiscal year (FY) 2024 budget request to its Chief of staff: Collaborative combat aircraft are entering the FY2024 presidential budget request; Collaborative Combat Aircraft (CCA) projects are estimated to be $500 million for perhaps "100 roles" in USAF missions in FY2024. The US Air Force plans to spend more than $6 billion on its CCA programs over the next five years (2023 to 2028).
List of CCAs
Several CCAs are or have been under development.
Examples include:
GA-ASI Gambit
General Atomics XQ-67
General Dynamics X-62 VISTA
Kratos XQ-58 Valkyrie
Skyborg Vanguard program entrants.
Boeing MQ-28 Ghost Bat
See also
Loyal wingman
Index of aviation articles
Notes and references
Unmanned military aircraft of the United States
Robotics
Command and control | Collaborative combat aircraft | [
"Engineering"
] | 2,181 | [
"Robotics",
"Automation"
] |
72,592,525 | https://en.wikipedia.org/wiki/Floating%20cable-stayed%20bridge | A floating cable-stayed bridge is a type of cable-stayed bridge where the towers float on tension-leg submerged material, tethered to the seabed for buoyancy. No floating cable-stayed bridge has been made or planned yet, a floating suspension bridge has been planned in Norway. This bridge could be more stable horizontally across the bridge than floating suspension bridges, the lateral movement force from the wind and current in the water is a problem trying to be resolved by placing the tethered cables at different angles from the floating platform to the seabed.
See also
Cable-stayed suspension bridge
Floating suspension bridge
List of cable-stayed bridges in the United States
List of longest cable-stayed bridge spans
List of longest suspension bridge spans
List of straits
References
Bridges by structural type
Structural engineering | Floating cable-stayed bridge | [
"Engineering"
] | 159 | [
"Structural engineering",
"Civil engineering",
"Construction"
] |
72,596,545 | https://en.wikipedia.org/wiki/Barbara%20Frisken | Barbara Frisken a Canadian physicist who is a professor at the Simon Fraser University. Her research considers soft matter and the realisation of Polymer Electrolyte Membrane Fuel Cells. She was President of the Canadian Association of Physicists.
Early life and education
Frisken is from Canada. Her father William Frisken, was a professor of Particle Physics at York University. She was an undergraduate student at Queen's University at Kingston, and moved to Northwestern University for a graduate degree. Frisken earned her doctorate at the University of British Columbia in 1990. Her doctoral research involved investigating the behaviour of nematic liquid crystals in electromagnetic fields. She moved to University of California, Santa Barbara, where she worked as a postdoctoral scholar.
Research and career
Frisken joined the faculty of Simon Fraser University in 1992, where she studies soft matter, and looks to uncover structure-property relationships in molecular systems. Frisken has studied gels, polymers and colloidal materials. She developed dynamic light scattering, a technique used to characterise the size of nanoparticles.
Frisken worked on novel polymeric materials for using in Polymer Electrolyte Membrane Fuel Cells. High conductivity in polymeric materials is related to the morphology and nanostructure. These materials can be designed to conduct anions or protons. Frisken has shown that continuity of the hydrophilic regions is critical to improving conductivity, whilst the hydrophobic regions contain the membrane size. Her research combines characterisation techniques such as small-angle X-ray scattering and neutron scattering with molecular dynamics simulations to understand and optimise polymeric materials.
In 2012, Chris Hadfield took some of Frisken's materials to the International Space Station to study crystallisation dynamics in space.
Academic service
In 2006, Frisken was made Chair of the Department of Physics at Simon Fraser University. She revamped undergraduate teaching, and continues to serve on their curriculum committee. She has held various positions in the Canadian Association of Physicists, including overseeing their Condensed Matter Physics division, the committee to Encourage Women in Physics and Committee on Academic Affairs. She was elected vice president in 2021, and President in 2022.
Selected publications
References
Year of birth missing (living people)
Living people
Canadian women physicists
20th-century Canadian physicists
20th-century Canadian women scientists
21st-century Canadian physicists
21st-century Canadian women scientists
Queen's University at Kingston alumni
Northwestern University alumni
University of British Columbia alumni
University of California, Santa Barbara people
Academic staff of Simon Fraser University
Women materials scientists and engineers
Canadian materials scientists
Polymer scientists and engineers
Presidents of the Canadian Association of Physicists | Barbara Frisken | [
"Chemistry",
"Materials_science",
"Technology"
] | 533 | [
"Polymer scientists and engineers",
"Physical chemists",
"Materials scientists and engineers",
"Polymer chemistry",
"Women materials scientists and engineers",
"Women in science and technology"
] |
72,596,889 | https://en.wikipedia.org/wiki/Hydrogen%20ozonide | Hydrogen ozonide () is a radical molecule consisting of a hydrogen atom covalently bonded to an ozonide unit.
It is possibly produced in the reaction of the hydroxyl radical with dioxygen: OH• + O2 → HO3•.
It has been detected in a mass spectrometer experiment using (protonated ozone) as precursor.
References
Extra reading
Oxoacids
Ozonides | Hydrogen ozonide | [
"Chemistry"
] | 87 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
72,597,265 | https://en.wikipedia.org/wiki/Liposome%20extruder | A liposome extruder is a device that prepares cell membranes, exosomes and also generates nanoscale liposome formulations. The liposome extruder employs the track-etched membrane to filter huge particles and achieve sterile filtration.
Function
A liposome is made up of phospholipid bilayers, with the liposome being a spherical vesicle. Phospholipid bilayers have both hydrophobic and hydrophilic properties, which are important characteristics of cell membranes. The hydrophobic ends of phospholipid molecules are constrained, often to each other, creating spherical liposomes that are smaller when the hydrophobic ends are exposed to a solution that is aqueous in nature. The preparation of liposomes results in the formation of the liposome extruder. A liposome extruder is characterized by the uniform, narrow size distribution of its output, and has a particle-size control mechanism that is highly precise. Complex, toxic, injectable products such as the antifungal liposomal Amphotericin B, or the liposomal cytotoxic anticancer agents doxorubicin, paclitaxel, irinotecan, Adriamycin, and cytarabine contain liposomes which are prepared using the liposome extruder.
The technology for extruding liposomes relies on the performance and structural characteristics of the lipid bilayers in the liposomal phospholipids. An external extrusion force pushes the vesicles of liposomes that are large through the polycarbonate membranes with pore sizes that are specific when the transition temperature of the phospholipids rises slightly due to the change in operating temperature. Re-polymerization of the multiple compartments pr liposomes that are large in particle size occurs, and smaller liposomes are created due to the rupturing of the membrane pores. Extrusion of liposomes occurs at a uniform size, based on the pore size in the polycarbonate membrane. This happens when the big vesicles are passed through the cell membrane with a nanopore size specified in size several times due to the extrusion of polycarbonate membranes having uniform and vertical nanopore distribution on the surface of the membrane.
Application
Liposome extruders are applied in the formulation of liposomes of homogeneous size distributions.
Types
Hand-Driven liposome extruders
This type of liposome extruder is primarily used in research laboratories, as it can process mini-sample volumes between 0.25 ml and 2.5 ml. The hand-driven liposome extruders are further categorized into liposome extruders with a thermal-jacketed option and liposome extruders under ambient temperature. They are operated by manually by pushing a plunger. Liposome extruders under ambient temperature can be fitted with a cooling jacket to regulate temperatures during liposome extrusion.
Jacketed liposome extruders
Jacketed liposome extruders are applied in laboratories and in pilot-scale research phases. They process volumes between 2 mL and 3 L. The jacketed extruders are fitted with barrels to regulate the temperatures of the samples. To drive this extruder, a compressed nitrogen cylinder is used.
Online liposome extruders
Online liposome extruders process volumes of between 2 ml and 20L. They are driven by a high-pressure electric pump, making them appropriate for use in pilot-scale liposome production.
Multiple liposome extruder system
A multiple liposome extruder system is fitted with pressure and temperature sensors and a control panel to regulate liposome production. it processes capacities of between 1L and 200L.
Gallery
References
Membrane biology
Drug delivery devices
Dosage forms
Applied genetics | Liposome extruder | [
"Chemistry"
] | 818 | [
"Pharmacology",
"Membrane biology",
"Drug delivery devices",
"Molecular biology"
] |
72,598,166 | https://en.wikipedia.org/wiki/Alma%20Y.%20Alan%C3%ADs | Alma Yolanda Alanís García (born 1980) is a Mexican electrical engineer and control theorist specializing in intelligent control, and in particular in the use of artificial neural networks for applications including the control of electric motors, robot manipulators, and unmanned aerial vehicles. She is a chair professor and researcher in the Department of Computational Sciences at the University of Guadalajara.
Education and career
Alanís was born in Durango in 1980, and earned an electrical engineering degree from the Durango Institute of Technology in 2002. She did her graduate study in electrical engineering at the Guadalajara unit of CINVESTAV, earning a master's degree in 2004 and completing her doctorate in 2007. Her dissertation, Discrete-time Neural Control: Application to Induction Motors, was jointly supervised by Edgar N. Sanchez and Alexander G. Loukianov.
She took her present position at the University of Guadalajara in 2008.
Books
Alanís is the coauthor of books including:
Discrete-Time High Order Neural Control: Trained with Kalman Filtering (with Edgar N. Sanchez and Alexander G. Loukianov, Springer Studies in Computational Intelligence 112, 2008)
Decentralized Neural Control: Application to Robotics (with Ramon García-Hernández, Michel López-Franco, Edgar N. Sanchez, and José A. Ruz-Hernández, Springer Studies in Systems, Decision and Control 96, 2017)
Discrete-Time Neural Observers: Analysis and Applications (with Edgar N. Sanchez, Academic Press, 2017)
Bio-inspired Algorithms for Engineering (with Nancy Arana-Daniel and Carlos López-Franco, Elsevier, 2018)
Neural Networks for Robotics: An Engineering Perspective (with Nancy Arana-Daniel and Carlos López-Franco, CRC Press, 2019)
Neural Networks Modeling and Control: Applications for Unknown Nonlinear Delayed Systems in Discrete Time (with Jorge D. Ríos, Nancy Arana-Daniel, Carlos López-Franco, Academic Press, 2020)
She is also co-editor of:
Artificial Neural Networks for Engineering Applications (with Nancy Arana-Daniel and Carlos López-Franco, Elsevier, 2019)
Recognition
Alanis is a member of the Mexican Academy of Sciences, elected in 2017.
References
External links
1980 births
Living people
People from Durango City
Mexican engineers
Mexican women engineers
Control theorists
Academic staff of the University of Guadalajara
Members of the Mexican Academy of Sciences | Alma Y. Alanís | [
"Engineering"
] | 467 | [
"Control engineering",
"Control theorists"
] |
74,007,634 | https://en.wikipedia.org/wiki/Operational%20design%20domain | Operational design domain (ODD) is a term for a particular operating context for an automated system, often used in the field of autonomous vehicles. The context is defined by a set of conditions, including environmental, geographical, time of day, and other conditions. For vehicles, traffic and roadway characteristics are included. Manufacturers use ODD to indicate where/how their product operates safely. A given system may operate differently according to the immediate ODD.
The concept presumes that automated systems have limitations. Relating system function to the ODD it supports is important for developers and regulators to establish and communicate safe operating conditions. Systems should operate within those limitations. Some systems recognize the ODD and modify their behavior accordingly. For example, an autonomous car might recognize that traffic is heavy and disable its automated lane change feature.
ODD is used for cars, for ships, trains, agricultural robots, and other robots.
Definitions
Various regulators have offered definitions of related terms:
Examples
In 2022, Mercedes-Benz announced a product with an ODD of Level 3 autonomous driving at 130 km/h.
See also
Scenario (vehicular automation)
References
Vehicular automation
Technical specifications
Robotics engineering | Operational design domain | [
"Technology",
"Engineering"
] | 231 | [
"Computer engineering",
"Robotics engineering",
"Vehicular automation",
"Automation",
"nan"
] |
74,008,312 | https://en.wikipedia.org/wiki/List%20of%20bombings%20during%20the%20War%20in%20Iraq%20%282013%E2%80%932017%29 | This article lists significant bombings during the Iraqi Civil War (2013–2017).
Bombings
This article lists all major bombings between 30 December 2013 and 9 December 2017. For bombings that occurred prior this date see List of bombings during the Iraq War or List of bombings during the Iraqi insurgency (2011–2013)
References
Insurgency
Lists of explosions | List of bombings during the War in Iraq (2013–2017) | [
"Chemistry"
] | 67 | [
"Lists of explosions",
"Explosions"
] |
74,009,456 | https://en.wikipedia.org/wiki/Prognosis%20of%20autism | There is currently no evidence of a cure for autism. The degree of symptoms can decrease, occasionally to the extent that people lose their diagnosis of autism; this occurs sometimes after intensive treatment and sometimes not. It is not known how often this outcome happens, with reported rates in unselected samples ranging from 3% to 25%. Although core difficulties tend to persist, symptoms often become less severe with age. Acquiring language before age six, having an IQ above 50, and having a marketable skill all predict better outcomes; independent living is unlikely in autistic people with higher support needs.
Developmental course
There are two possible developmental courses of autism. One course of development is more gradual in nature, with symptoms appearing fairly early in life and persisting. A second course of development is characterized by normal or near-normal development before onset of regression or loss of skills, which is known as regressive autism.
Gradual autism development
Most parents report that the onset of autism features appear within the first or second year of life. This course of development is fairly gradual, in that parents typically report concerns in development over the first two years of life and diagnosis can be made around 3–4 years of age. Overt features gradually begin after the age of six months, become established by age two or three years, and tend to continue through adulthood, although often in more muted form. Some of the early signs of autism in this course include decreased attention at faces, failure to obviously respond when name is called, failure to show interests by showing or pointing, and delayed imaginative play.
Regressive autism development
Regressive autism occurs when a child appears to develop typically but then starts to lose speech and social skills and is subsequently diagnosed with ASD. Other terms used to describe regression in children with autism are autism with regression, autistic regression, setback-type autism, and acquired autistic syndrome.
Within the regressive autism developmental course, there are two patterns. The first pattern is when developmental losses occur in the first 15 months to 3 years. The second pattern, childhood disintegrative disorder (a diagnosis now included under ASD in the DSM, but not the ICD), is characterized by regression after normal development in the first 3 to 4, or even up to 9 years of life.
After the regression, the child follows the standard pattern of autistic neurological development. The term regressive autism refers to the appearance that neurological development has reversed; it is actually only the affected developmental skills, rather than the neurology as a whole, that regresses.
Usually, the apparent onset of regressive autism can be surprising and distressing to parents, who often initially suspect severe hearing loss. Attribution of regression to environmental stress factors may result in a delay in diagnosis.
There is no standard definition for regression. Some children show a mixture of features, with some early delays and some later losses; and there is evidence of a continuous spectrum of behaviors, rather than, or in addition to, a black-and-white distinction, between autism with and without regression. There are several intermediate types of development, which do not neatly fit into either the traditional early onset or the regressive categories, including mixtures of early deficits, failures to progress, subtle diminishment, and obvious losses.
Regression may occur in a variety of domains, including communication, social, cognitive, and self-help skills; however, the most common regression is loss of language. Some children lose social development instead of language; some lose both. Skill loss may be quite rapid, or may be slow and preceded by a lengthy period of no skill progression; the loss may be accompanied by reduced social play or increased irritability. The temporarily acquired skills typically amount to a few words of spoken language, and may include some rudimentary social perception.
The prevalence of regression varies depending on the definition used. If regression is defined strictly to require loss of language, it is less common; if defined more broadly, to include cases where language is preserved but social interaction is diminished, it is more common. Although regressive autism is often thought to be a less common (compared with gradual course of autism onset described above), this remains an area of ongoing debate; some evidence suggests that a pattern of regressive autism may be more common than previously thought. There are some who believe that regressive autism is simply early-onset autism which was recognized at a later date. Researchers have conducted studies to determine whether regressive autism is a distinct subset of ASD, but the results of these studies have contradicted one another.
Differential outcomes
There continues to be a debate over the differential outcomes based on these two developmental courses. Some studies suggest that regression is associated with poorer outcomes and others report no differences between those with early gradual onset and those who experience a regression period. While there is conflicting evidence surrounding language outcomes in autism, some studies have shown that cognitive and language abilities at age may help predict language proficiency and production after age 5. Overall, the literature stresses the importance of early intervention in achieving positive longitudinal outcomes.
Academic performance
The number of students identified and served as eligible for autism services in the United States has increased from 5,413 children in 1991–1992 to 370,011 children in the 2010–2011 academic school year. The United States Department of Health and Human Services reported approximately 1 in 68 children are diagnosed with autism at age 8, and onset is typically between ages 2 and 4.
The increasing number of students diagnosed with autism in the schools presents significant challenges to teachers, school psychologists, and other school professionals. These challenges include developing a consistent practice that best support the social and cognitive development of the increasing number of autistic students. Although there is considerable research addressing assessment, identification, and support services for autistic children, there is a need for further research focused on these topics within the school context. Further research on appropriate support services for students with ASD will provide school psychologists and other education professionals with specific directions for advocacy and service delivery that aim to enhance school outcomes for students with ASD.
Attempts to identify and use best intervention practices for students with autism also pose a challenge due to over dependence on popular or well-known interventions and curricula. Some evidence suggests that although these interventions work for some students, there remains a lack of specificity for which type of student, under what environmental conditions (one-on-one, specialized instruction or general education) and for which targeted deficits they work best. More research is needed to identify what assessment methods are most effective for identifying the level of educational needs for students with ASD. Additionally, children living in higher resources settings in the United States tend to experience earlier ASD interventions than children in lower resource settings (e.g. rural areas).
A difficulty for academic performance in students with autism is the tendency to generalize learning. Learning is different for each student, which is the same for students with autism. To assist in learning, accommodations are commonly put into place for students with differing abilities. The existing schema of these students works in different ways and can be adjusted to best support the educational development for each student.
The cost of educating a student with autism in the US would be about $20,600 while educating an average student would be about $12,000.
Though much of the focus on early childhood intervention for autism has centered on high-income countries like the United States, some of the most significant unmet needs for autistic individuals are in low- and middle-income countries. In these contexts, research has been more limited but there is evidence to suggest that some comprehensive care plans can be successfully delivered by non-specialists in schools and in the community.
Adulthood
Many autistic people face significant obstacles in transitioning to adulthood. Autistic people may face socialization issues, which may impact relationships such as community participation, employment, independent living, friendships, dating and marriage, and having children. Some autistic adults are unable to live independently.
Employment
The majority of the economic burden of autism is caused by lost productivity in the job market. Compared to the general population, autistic people are more likely to be unemployed and to have never had a job. About half of people in their 20s with autism are not employed.
In various developed countries, the autism unemployment rate can range from 62% to as high as 85%., although in some it can be as low as 25%. While employers state hiring concerns about productivity and supervision, experienced employers of autistics give positive reports of above average memory and detail orientation as well as a high regard for rules and procedure in autistic employees.
From the perspective of the social model of disability, much of this unemployment is caused by the lack of understanding from employers and coworkers. Adding content related to autism in existing diversity training can clarify misconceptions, support employees, and help provide new opportunities for autistic people. As of 2021, new autism employment initiatives by major employers in the United States continue to grow, as the initiative "Autism at Work" grew to 20 of the largest companies in the United States. However, special hiring programs remain largely limited to entry-level technology positions, such as software testing, and exclude those who have talents outside of technology. An alternative approach is systemic neurodiversity inclusion. Developing organizational systems with enough flexibility and fairness to include autistic employees improves the work experience of all employees.
References
Developmental psychology
Learning disabilities | Prognosis of autism | [
"Biology"
] | 1,928 | [
"Behavioural sciences",
"Behavior",
"Developmental psychology"
] |
74,009,921 | https://en.wikipedia.org/wiki/Scenario%20%28vehicular%20automation%29 | In the field of vehicular automation a scenario denotes a sequence of snapshots of the environment and the actions of a vehicle. Scenarios are created to represent real-world situations and are used for development, testing, and validation purposes.
Standards
Operational design domain
According to ASAM's OpenODD concept paper, scenarios are related to operational design domain. However, they are not the same. Defining the appropriate behavior of actors within an ODD creates a scenario that is not dependent on any ODD definition.
History
In 2022, Netherlands Organisation for Applied Scientific Research announced scenario-based safety validation of self-driving trucks in cooperation with Torc Robotics.
See also
Verification and validation
References
Vehicular automation
Robotics
Technical specifications | Scenario (vehicular automation) | [
"Technology",
"Engineering"
] | 145 | [
"Robotics",
"Vehicular automation",
"Automation",
"nan"
] |
74,010,797 | https://en.wikipedia.org/wiki/Kialo | Kialo is an online structured debate platform with argument maps in the form of debate trees. It is a collaborative reasoning tool for thoughtful discussion, understanding different points of view, and collaborative decision-making, showing arguments for and against claims underneath user-submitted theses or questions.
The deliberative discourse platform is designed to present hundreds of supporting or opposing arguments in a dynamic argument tree and is streamlined for rational civil debate on topics such as philosophical questions, policy deliberations, entertainment, ethics, science questions, and unsolved problems or subjects of disagreement in general.
Argument-boxes are structured into hierarchical branches where the root is the main thesis (or theses) of the debate, enabling deliberation and navigable debates between opposing perspectives. A debate is divided into Pro (supporting) and Con (refuting or devaluing) columns where registered users can add arguments and rate the of the parent claim. The arguments .
Its argument tree structure enables detailed scrutiny of claims at all levels of the tree and allows users to for example quickly understand why a decision was made or which of the aggregated arguments swayed it this way. Newcomers can join a debate at any time and look back at the structured discussion history, and then weigh in at the right place with their new argument or their comment on a specific argument. The design presets a structure on debates "that allows participants to easily see, process, and ultimately assess the many facets of competing claims".
The word Kialo is Esperanto for "reason". The platform is the world's largest argument mapping and structured debate site.
Overview
Users can comment on every Pro or Con, for example for requesting sources or expansions. Recent activities of a debate are shown in a panel on the right side of the respective debate. Debates can be found through the search or on the Explore page through their descriptions and topic-tags.
Mere comments that do not make a constructive point (a self-contained argument backed by reasoning) are not allowed and are picked up by other users and moderators. "Civil language and sensible observations from opposing perspectives" can be seen also in debates about controversial topics. The site by-design incentivizes fair, rigorous, open-minded dialogue. Contributors making claims often also write counterpoints to their own contribution. Claims need to be shorter than 500 characters and can link to external sources.
Debate trees can also start off with multiple theses – such as or hypotheses. Claims can link to related debates or include segments of them. In the discussion tab of each claim, users can make edit proposals (e.g. for accuracy, improving sources, or changing scope), decide if the argument should be moved or copied to another branch, call for archiving a claim, and ask for extra evidence or clarification.
Debates can grow large and complex for which a sunburst diagram and the search functionality can be useful. Each debate also has a chat-box. In cases where e.g. a "Con" is a point against multiple in the "Pros", users – through moderators – can link these arguments at the respective places to avoid duplication of content and allowing a clean chain for people to understand which points are arguments against each other. Contributions of users are tracked, enabling a board of thought-leaders for every debate. Other gamification elements include a feature to thank users for their contributions.
The "Perspectives" feature allows users to see 'Impact' ratings of supporters and opposers of a thesis as well as of the debate's moderators and individual contributors. It thereby enables participants to see a debate from other participants' perspectives and to sort by them. In Kialo Edu, this feature lets teachers view votes for a whole class, individuals, or supporters/opponents of a specific thesis. Users in both versions of Kialo can vote on the overall debate topic as well as on individual claims to express their perspectives or conclusions, with the rationale (i.e. the main causal arguments) why they voted on the veracity of the thesis as they did not being captured. Voting can be done by any registered user while navigating through any debate that has voting enabled or via using the Guided Voting wizard user interface that automatically walks through branches.
As of 2021, Kialo doesn't have a mobile app.
Contents
A 2018 report stated the collaborative argument platform hosts more than 10,000 debates in various languages. It also hosts private debates. The website claims that it has over 18,000 public debates as of July 2023, as well as over 1 million votes and over 720,000 claims. Debates can be found via the site's internal search and up to six tags per debate.
Preprint studies have scraped public debates on over 1.4K issues with over 130K statements as of October 2019 and 1628 debates, related to over 1120 categories, with 124,312 unique claims as of June 26, 2020.
Kialo Inc.
The site is run by Kialo Inc. It was founded by German-born entrepreneur and London School of Economics and Political Science graduate Errikos Pitsos in August 2017 and is based in Brooklyn and Berlin. According to a 2018 report, the site does not show advertisements and does not sell user's data. The for-profit company was founded in 2011, Pitsos began to develop the concept in 2012 and described various specifics of the system in 2014. In 2018, he stated that they intend to make money by selling the platform to companies as a deliberation and decision-making tool. The site is free to use for the public and in education. According to the site, as of 2023 Kialo.com is a non-revenue generating site with no ads and no reselling of user data.
Applications and adoption
Adopted applications
Applications of its content or the platform in society include:
Teachers and professors, especially in high schools – including the universities Harvard and Princeton, are using Kialo for class discussions and exercises in critical thinking and reasoning, as consolidating understanding of materials covered in recent classes, more useful and engaging learning experiences, for remote/e-learning, for clearing up misconceptions, teaching logical fallacies and rational argumentation, for academic dialogue, teaching media literacy, and for teaching to sufficiently reflect or research before posting online. Like for debaters of the main site, access for schools and universities is free. is the custom version of Kialo specifically designed for classroom use where debates are private and locked to invited students.
Kialo allows teachers to provide feedback to students on their ideas, argument structure, and research quality while it is left to other students to rate the impacts of their peers' arguments.
Students can be allowed to contribute anonymously which may be useful for controversial issues as well as for safeguarding privacy in education.
Students are or can be encouraged to back up their claims with evidence which can foster digital literacy and research skills.
Students and teachers can use it to arrange their thoughts when structuring an essay or project.
The site's name was decided on internally using the software.
Prototypical and theoretical applications
Potential, theoretical, prototypical or little-used applications include:
Education
Improving critical thinking skills of society at large as well as facilitating deep or efficient thinking and deepening research and debates where e.g. discussions are less shallow and the well-known or many arguments have already been made and in many cases aren't unreasonably over- or underrated.
Pitsos claimed that "we're training students to be very good test-takers instead of critical thinkers", suggesting teaching people to think things through may be more important or neglected compared to essay writing skills.
Many young people and adults are "submerged into a sea of dispersed information", "[b]rowsing and engaging in superficial thinking activities". Kialo could counteract this issue and help people develop good sane reasoning.
Academia, R&D and policy
Three scholars from three prestigious U.S. universities outlined possible benefits in this domain, including applications beyond higher education such as for academic communication. They suggest the debate platform could be used for structuring the communication of open peer-review by helping those giving feedback to "hone in on[sic] core arguments and pieces of evidence in an even more direct way" than annotated commenting.
It could be used to evaluate extracted argument structures and sequences from raw texts, as in a Semantic Web for arguments. Such "argument mining", to which Kialo is the largest structured source so far, could e.g. be used to assess the completeness and effectiveness of an argumentative discussion or to augment it (with additional arguments, contextual information, assessments, refuting evidence or supporting data).
A security studies paper suggested it could be used for "managing arguments more effectively than traditional paragraph/bullet-point approaches". It claims that "complexity demands adaptation" but also notes that "Kialo's simplicity does pose some weaknesses and limitations, and in general current systems cannot reliably automate analysis or synthesis of arguments in the same way that statistical packages can automate analysis of data".
The site could be used by companies and government organizations as "intuitive debate software for internal discussions and decision-making".
It could aid in the search for the best policies and course of action, including for 'wicked problems' and issues where there is a large polarization. This may include "experiments of deliberative democracy inside local governments".
With a platform like Kialo, users provide "both data on what they see is in the landscape of relevant arguments but also some indication of what they think is important [or has priority] in determining their policy preferences" and "also shows which arguments the individual did not find persuasive, and possibly which rebuttals to a particular argument [was] used to discard it." Current functionality of the site may still be insufficient for the latter outside of experiments.
It could increase efficiency in knowledge acquisition, including concerning information overload on social media.
Policy-makers and scientists could use platforms and debates like these to engage with each other as well as the public if they were aware of it and used it. Considering only argument trees beneath theses, its arguments-crowdsourcing and revision principles are not or less vulnerable to framing-issues, intentionally placed attackable segments, weak or missing arguments, straw man points, oversimplification, agenda-setting and other issues that may be common in contemporary public political debates.
The debate trees can be used to identify arguments that are seen as most credible, as well as reveal which areas of argumentation lack support, precedent, or evidence, which may be useful for subsequent work or more efficient and useful science (as in identifying little-supported assumptions, providing key missing data, or researching key open questions).
General
Writers in general, as well as possibly major other opinion leaders, could populate a Kialo debate with their arguments and release it alongside the traditional linear written format, albeit such would mean the arguments would be open to scrutiny, with such being more accessible than large and fans-dominated unstructured comment sections or may already be part of an existing debate tree. They could also use the site in other ways such as for selecting questions to pose to interviewees or for selecting unexplored questions to investigate and report on.
It could be used for legal cases.
Websites could embed read-only argument trees (or branches) from the site.
More broadly, the site's content could be used for reflective brainstorming, and as a crowdsourcing resource for points to use in other media (e.g. long-form text). It enables detailed exploration of some theses or topics as the visual reasoning through tree-based structure allows for many levels of depth and for follow-up questions in the discussion tab of each claim. The founder stated that "The public debates are basically supposed to become a site where people can go and inform themselves. If a debate has over 2,000 unique arguments, it's going to be hard to find an argument that's not in there already. You can go there, similar to Wikipedia, and read."
Research
Kialo is a subject of research studies and its data has been used in research as there are datasets of its contents and the site allows exporting CSV files as well as crawling and filtering debates.
Computational research on argumentation
The platform has gained attention in computational research on argumentation because of its high-quality arguments and elaborate argument trees. Its data has been used to train and to evaluate natural language processing AI systems such as, most commonly, BERT and its variants. This includes argument extraction, conclusion generation, argument assessment, machine argumentative debate generation or participation, surfacing most relevant previously overlooked viewpoints or arguments, argumentative writing support (incl. sentence attackability scores), automatic real-time evaluation of how truthful or convincing a sentence is (similar to fact-checking), language model fine tuning (incl. chatbots), argument impact prediction, argument classification and polarity prediction.
Content analysis in social science and belief studies
The contents can also be analyzed to e.g. show the most common Con rationale-types and factors in general, or reveal the most contested arguments where ratings diverge the most for a given topic.
The site's founder proposed the types of arguments and ways people reason could be investigated as well as the "performance of Kialo versus long-form text in making people change their minds". One study suggests arguers seem to change their viewpoints more readily when a fact they believe has evidence and is undermined when compared to prior beliefs without .
The platform as a subject
A study showed that when evaluating policies via Kialo debates, "reading comments from most to least liked, on average, displays more [winning arguments] than reading comments earliest first". Kialo has a set of different permissions that participants can have in a given debate. A preprint study makes suggestions regarding "interface design as a scalable solution to conflict management" to prevent adversarial beliefs and values of moderators to have negative impacts on the site.
Reception, motivation and distinction from alternatives
In 2022, MakeUseOf named the site as one of the five best "debate sites to civilly and logically argue online about opinions" and in 2019 as one of the "100+ best websites on the Internet".
Online discourse quality
The site aims to be a hub for civilized debate where shouting, rudeness or irrationality aren't allowed. This has been described as remarkable in an "age of Trumpian tweeting". The site's founder stated that he noticed early on that the Web became "ideal for bad conversations, with prominence given to the most outrageous conversations" and that he "wondered if there wasn't a better method of online discourse", claiming the site's mission is to "empower reason and to make the world more thoughtful", describing it as a "platform where people with opposing views can meet and understand each other's thinking". As of 2023, there are major concerns about online irrational or misinformation-fueled debate – for example, a researcher affirmed that "Twitter was not designed or intended to be a digital town square" as part of a "functioning democracy", addressing Elon Musk's comments about the site in 2022. Instead, she claims it to be a "space for millions of town criers, but not a town square for people to come together and debate". Reports suggest the site may present a more complete and complex view of reality than some other sites where "it's easy to get trapped in echo-chambers of like-minded people where your beliefs are never [meaningfully] challenged" as it shows you "the best arguments on both sides of a debate".
Communication formats
e.g. "tend to only allow a linear progression of arguments in a stream-of-discussion format". On many websites, "circuitous comment threads [often] render meaningful discussion impossible" and "formats that we use to communicate shape the way we communicate". On the site, users contribute to a debate tree rather than engaging in argumentative back-and-forth commenting.
Kialo may be more appropriate especially for discussions that are relatively complex and hard to visualize or oversee otherwise and allows for public ideation and structured interaction among different types of stakeholders. Linking to supporting evidence is encouraged, but not as strictly required as for example on Wikipedia. Kialo has advantages over structured knowledge bases and Wikipedia in "that it includes many debatable statements; many attacked sentences are subjective judgments, so fact-based knowledge sources may have limited utility". Chains of reasoning can be followed "from beginning to end" with relatively little text to read, nearly no repetition or unexplained statements and without having it derailed by for example "name-calling and directionless ranting". Online debates "have grown so large and acrimonious that no one realistically has the time to read everything and hence get a sense of the actually winning arguments (winners) after all points have been considered" and there is research into how to efficiently calculate the winning arguments or arguments weights and the overall conclusions. Moreover, argumentations on the site are less fleeting and repetitive than debates on social media sites – they are commonly read and actively contributed to over the span of years.
Criticisms and current limitations
One preprint study stated that "[t]hough kialo is designed for scale, and therefore has to be not only robust but also both easy and appealing to use, it has simplified its notion of argument structure so much that there is very little flexibility left. As a commercial entity, its data [not reusable] and platform [not open source] are also closed, making wide-scale application at the science-policy interface more challenging."
One study found that "Kialo's simplicity does pose some weaknesses and limitations" and found the functionality of current systems including Kialo for "synthesis of arguments" to be insufficient. One study suggests the platform is structured in a way that gives insufficient capacity for users to do anything else other than to either agree or disagree with a side, with there e.g. only being options to rate the veracity of the main thesis but not for proposing concrete alternatives and middle-grounds such as more nuanced policies or specifying conditional critical considerations (e.g. exceptions, applicable scopes and limitations) of one's veracity rating of the main thesis, which tend to be very brief and rarely revised.
One study points out that without 'Writer' permissions in a debate, the arguments have "to get past the gatekeepers" of it, which can in some cases be problematic as moderators' beliefs and values may play a role. For instance, such can lead to some users feeling like certain perspectives (or arguments) are being excluded from a debate or getting positioned inappropriately (such as not being visible at the level most relevant). There may be issues relating to framing and argument positioning, whereby for example a false claim (with or without a source) can be added as supporting a thesis which is then only addressed by a later countering claim stating the opposite beneath it – which may reduce the former's 'Impact' rating but is not shown directly at the tree level above as an 'countering' argument. Instead, only the false or weak supporting argument can be seen at the level above in such a case. Impact rating votes do not require reading the arguments beneath but voting can be turned off until the argument map has had time to sufficiently develop.
Complementarity
The founder clarified key distinctions and complementarity of the site saying "We're going to just be an added place. We're not competing with anybody out there with regards to thoughtful discourse. There are a couple of sites that are question-and-answer sites, or commenting sites, or sharing sites, but there's not a single [major] site for collaborative reasoning — a repository of the why". He states that Wikipedia – another peer production site to which Kialo is sometimes compared with due to argumentative discussions on Talk pages and its public collaborative knowledge integration – "tells you the what and we tell you the why".
See also
Evidence-based practices – potential uses
Public awareness of science – platform use can expose people to most relevant counterarguments and data
Internet manipulation#Countermeasures – related risks
Knowledge integration – argument integration
List of logical fallacies – potential way to classify arguments or removals
Socratic method – related educational concept
The medium is the message – importance of platform structure-design
Causal inference – related to identification of data needs
r/changemyview – an unstructured debate website
Project Debater – an AI system
References
External links
Kialo Edu blog, guides and ideas for applications in education
Structured online debate and conclusion-making, images and related projects
The Role of Pragmatic and Discourse Context in Determining Argument Impact, 2019, R&D on determining argument impact
2017 establishments in New York City
2017 in science
Argument mapping
Argument technology
Companies based in Brooklyn
Software companies established in 2017
Computational linguistics
Collaborative projects
Collective intelligence
Crowdsourcing
Debate websites
Educational software
Government by algorithm
Online companies of the United States
Open government
Philosophy websites
Semantic Web
Virtual communities
Web 2.0 | Kialo | [
"Technology",
"Engineering"
] | 4,358 | [
"Natural language and computing",
"Computational linguistics",
"Government by algorithm",
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74,011,624 | https://en.wikipedia.org/wiki/Vidmeter | Vidmeter was a viral video analytics service that launched in 2007. The site tracked the top 100 Internet videos across multiple Internet video websites such as YouTube and Vimeo. During the lawsuit Viacom International Inc. v. YouTube, Inc., Vidmeter published a study showing Viacom videos accounted for a relatively small portion of YouTube's view count. In 2008, Vidmeter was acquired by Visible Measures for an undisclosed sum.
References
Websites | Vidmeter | [
"Technology"
] | 92 | [
"Computing stubs",
"World Wide Web stubs"
] |
74,011,849 | https://en.wikipedia.org/wiki/Centre%20Port | Centre Port is a proposed development across The Wash in Eastern England, which would link Norfolk and Lincolnshire by road. The plan is to link Hunstanton in Norfolk, with Gibraltar Point in Lincolnshire, creating an road, with a port and a railway at the midway point. Additionally the development would be a tidal barrage to prevent sea flooding, and would use tidal power to create enough electricity to power 600,000 homes. Whilst no formal plans have yet been submitted, the scheme has come under widespread criticism from those living in the area and from wildlife groups.
History
The Wash is a large tidal area between the counties of Lincolnshire and Norfolk on the eastern coast of England. The Wash is fed by several major watercourses, the main ones are: (anticlockwise from the north) the Steeping River, River Witham, River Welland, River Nene and the River Great Ouse, and covers an area of . The Nene, Ouse, Walland and Witham, collectively discharge an average flow of ( per day.) fresh water into The Wash. The sea area of The Wash is significantly smaller than it was in the 16th century, as much of the land has been reclaimed - places such as Wisbech, now far inland, were subjected to flooding such as in 1236 when hundreds died in a massive sea-storm. A large swathe of land bordered by Boston in the north, Peterborough in the west, Wisbech and Ely in the south, and King's Lynn in the east which fringes the coastline of The Wash is still below sea level. The Wash is an estuary (or embayment) which has deep channels, intertidal sandbanks and mudflats, while the coastline fringing the two counties of Lincolnshire and Norfolk has extensive saltmarshes.
The proposal to build a barrage across the wash was first mooted in the 1960s, however, the plan then was that it would involve reclaiming some of land and the diversion of fresh water spilling into the wash to feed water requirements in the south-east of England, particularly for agricultural needs. This would require a sea wall some in depth, releasing of fresh water per day. The scheme was costed between £150 million and £287 million, saving an annual bill of £300,000 on sea wall repairs in The Wash area. The project was dropped when the approval for a large on-land reservoir (Rutland Water) passed in Parliament.
Plans were also announced in the 1970s with a barrage much further south in The Wash, but the consultant engineers stated that the project was beyond their technology, something with which a team of Dutch engineers agreed. However, the Wash Water Storage Scheme was developed to determine the project's feasibility, in terms of its geological, and ecological impacts. Further schemes were mooted in 2008, and again in 2019 when the Environment Agency suggested such a plan to protect flooding damage to King's Lynn.
In 2023, The Wash, and other associated wetlands in Britain which are part of the East Atlantic Flyway, were nominated for UNESCO World Heritage status. The Wash estuary has several recognised protections, notably EMS (European Marine Site), NNR, RAMSAR, SAC, SSSI, and SPA.
The 2022 proposal
Developer Port Evo announced plans in November 2022 to develop a tidal barrage across The Wash. This would include a causeway with an road along the entire length of the barrage, and also include:
a container port known as Centre Port, capable of handling ships carrying 23,000 twenty-foot equivalent units
a railway linking onto the Poacher Line in Lincolnshire
a tidal energy scheme to generate electricity for 600,000 homes
sea flood prevention of The Wash area
The port would provide a deep-water trans-shipment point for container traffic by rail. This would feed into the line between and , providing a quicker route into the Midlands and Northern England than the current route from the East Anglian ports. The road would be a dual-carriageway from the container port area to Wainfleet, and a single-carriage road from the port to Hunstanton in the south in what would be a 20-minute journey end-to-end. The project has an initial estimate of 2028 for completion.
Support
The energy firm Centrica announced their support and funding towards a feasibility study. The managing director of the firm said "We’re excited to help Centre Port explore their ambitious plans for The Wash. The project represents one of the largest tidal power schemes anywhere in the world and would provide a reliable source of green energy to the UK."
Objections
In November 2022, the National Trust stated "The Wash is one of the most important estuaries in the UK. Therefore, news of a potential new container terminal and tidal scheme in an area designated for its importance to wildlife, is deeply concerning." They also said: "Some bold claims are being made about ecology and we are keen to seek further information on the detailed plans and data to back these up. We are ready to scrutinise these plans and hold developers to account on their promises."
Greenpeace were similarly critical of the effect on wildlife. Their chief scientist was quoted as saying: "Greenpeace remains highly sceptical that a tidal barrage on the Wash is a useful project, and it should certainly not be a priority for government support. Given the environmental impacts, needs for port infrastructure or flood defence should be met in a more targeted way." The RSPB labelled the project as "outlandish, [and] unworkable."
Both the Lincolnshire Wildlife Trust, and the Wild Ken Hill nature reserve in Norfolk object to the scheme. The latter pointed out that "...The way the Wash works is it’s quite a dynamic wilderness, so you get very complex movements of water and sediment which creates a mosaic of mudflats, salt marsh, channels, tidal streams … and that is what makes it so great for wildlife. Over 2 million birds visit a year, it hosts 50% of Europe’s common seals, and it has eels which are critically endangered globally. To interfere with those processes is highly likely to be very damaging."
See also
Cardiff Bay Barrage
Mersey Barrage
Outer Trial Bank - a trial for fresh water storage in The Wash in the 1970s
Severn Barrage
Notes
References
Sources
External links
Map of reclaimed land around The Wash
Tidal barrages
Proposed tidal power stations
Power stations in Lincolnshire
Coastal construction
Geography of Lincolnshire
Flood barriers
Proposed renewable energy power stations in England
Flood control in the United Kingdom
Proposed infrastructure in England | Centre Port | [
"Engineering"
] | 1,330 | [
"Construction",
"Coastal construction"
] |
74,012,932 | https://en.wikipedia.org/wiki/Macromolecular%20Crystallographic%20Information%20File | The Macromolecular Crystallographic Information File (mmCIF) also known as PDBx/mmCIF is a standard text file format for representing macromolecular structure data, developed by the International Union of Crystallography (IUCr) and the Protein Data Bank It is an extension of the Crystallographic Information File (CIF), specifically for macromolecular data, such as proteins and nucleic acids, incorporating elements from the PDB file format.
mmCIF is intended as an alternative to the Protein Data Bank (PDB) format and is now the default format used by the Protein Data Bank.
mmCIF was designed to address limitations of the PDB format in terms of capacity and flexibility, especially with the increasing size and complexity of macromolecular structures being determined.
The format is part of the larger Crystallographic Information Framework, a system of exchange protocols based on data dictionaries and relational rules expressible in different machine-readable manifestations, including, but not restricted to, the original Crystallographic Information File and XML.
Example
An example of the mmCIF file format is key-value style is:
_cell.entry_id 4HHB
_cell.length_a 63.150
_cell.length_b 83.590
_cell.length_c 53.800
_cell.angle_alpha 90.00
_cell.angle_beta 99.34
_cell.angle_gamma 90.00
_cell.Z_PDB 4
External links
International Union of Crystallography
wwPDB: mmCIF Resources
PDBx/mmCIF conversion service
References
Chemical file formats
Computer file formats
Crystallography
Biological sequence format | Macromolecular Crystallographic Information File | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering",
"Biology"
] | 351 | [
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"Chemistry software",
"Materials science",
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"Bioinformatics",
"Crystallography",
"Condensed matter physics",
"Biological sequence format",
"Chemical file formats"
] |
74,014,106 | https://en.wikipedia.org/wiki/IEEE%20P80 | IEEE standard P80 is a technical standard of the Institute of Electrical and Electronics Engineers (IEEE), governing outdoor AC substations (although under special circumstances it may also be applied to indoor AC substations). It was last approved on the 28th September, 2017. The standard governs requirements for the grounding and insulation of substations for safety purposes. The standard, along with IEEE P81, is widely used within the industry in power applications.
Specifications
For AC currents at the frequency used for power grids (i.e. 50 or 60 Hz), the threshold of lethality for current passing through the human body is only 0.1 A, although this value can be much higher for short surges, or for higher frequencies. As a result, the standard recommends an emphasis on fast fault clearing time in order to reduce both the probability and duration of any potential exposure of humans to dangerous fault current.
In general, a system of horizontal grid conductors and vertical rods and electrodes is recommended. Ths is to reduce the aforementioned fault clearing time, as well as ensuring that there are multiple paths for a high fault current to dissipate, ensuring that ground potential gradients dangerous to those standing near the substation will not occur. An example implementation given consists of copper rods buried 0.3-0.5m below ground, and spaced 3-7m apart. In situations where space is at a premium, or other difficulties prevent the construction of a proper grounding grid, ground rods may be driven in deeper, and a wire mat may also be used.
References
IEEE standards | IEEE P80 | [
"Technology"
] | 325 | [
"Computer standards",
"IEEE standards"
] |
74,014,119 | https://en.wikipedia.org/wiki/Candelariella%20lichenicola | Candelariella lichenicola is a rare species of lichenicolous (lichen-dwelling) fungus in the family Candelariaceae. This species was first found in Sonora, Mexico, and is characterised by its distinct spore shape and chemical composition. It is typically found growing on the lichen species Candelina submexicana, and while not widespread, it contributes to the ecological diversity of the regions it inhabits.
Taxonomy
Candelariella lichenicola was first described by Swedish lichenologist Martin Westberg in 2007. The specific epithet lichenicola is derived from Latin, with lichen referring to its habitat and cola meaning "dweller" – together indicating that this species "dwells on lichens". The type specimen was found by Thomas Hawkes Nash III in 1975 in a canyon above the mining town of Trinidad, located in Sonora, Mexico, at an elevation of . This fungus belongs to the family Candelariaceae, which is known for a characteristic apical in the ascus of the fungi.
Description
While many species of fungi feature a thallus, or vegetative tissue, Candelariella lichenicola does not. Instead, it is defined by its distinctive apothecia, which are tiny, cup-shaped structures that contain the spore-producing organs. These emerge from the of its host lichen, with a diameter up to 0.25 mm. Its , the sexual spores within the asci, are more or less citriform (lemon-shaped) with pointed ends, and have typical dimensions of 11.5–14.0 by 4.5–5.0 μm.
The , the outermost layer of the fungal tissue, is reddish yellow to yellow-brown in colour, while the hymenium (the layer beneath the epihymenium) is colourless. The hymenium is moderately tall, ranging between 45 and 55 μm.
Two main secondary chemicals have been found in this species: calycin and pulvic acid lactone. These compounds are found at rates of 80% and 20% respectively. In terms of standard chemical spot tests, C. lichenicola is K+ (reddish), KC−, and C−.
Candelariella lichenicola shares many traits with other members of its genus, the vast majority of which are lichens. The unique spore shape of this species, while unusual, is not entirely unique within Candelariella and can be found in a few other species such as C. citrina. Similarly, while the (a type of cell in the hymenium) in most Candelariella species are or sparingly branched near the apices, in C. lichenicola, most paraphyses are branched in the mid-hymenium.
Habitat and distribution
Candelariella lichenicola appears to exclusively grow on Candelina submexicana, a species of lichen that prefers siliceous rocks found in southwestern North America's interior desert and at high altitudes. This fungus is currently known from three locations in northwestern Mexico. The lichenicolous fungus does not seem to inflict any damage on the host lichen, with no noticeable discolouration or other visible effects on the thallus.
Despite Candelina submexicana being common across southwestern North America, C. lichenicola is not widespread. The fungus is diminutive, easily overlooked, and seems to be a rare species, contributing to its limited observed distribution.
References
lichenicola
Fungi of Mexico
Fungi described in 2007
Lichenicolous fungi
Fungus species | Candelariella lichenicola | [
"Biology"
] | 750 | [
"Fungi",
"Fungus species"
] |
74,014,351 | https://en.wikipedia.org/wiki/Clandestinotrema%20portoricense | Clandestinotrema portoricense is a rare species of corticolous (bark-dwelling) crustose lichen in the family Graphidaceae. Found in Puerto Rico, it was described as a new species in 2014. It is characterised by its white, slightly shiny thallus that can span several centimetres in diameter, and its rounded that are immersed in the thallus. Unlike most of its genus counterparts, C. portoricense possesses septated (partitioned) spores and a carbonised (blackened) and , effectively distinguishing it from similar species.
Taxonomy
Clandestinotrema portoricense was first formally described by lichenologists Joel Mercado-Díaz, Robert Lücking, and Sittiporn Parnmen. The holotype, the initial specimen that serves as the basis for its description, was discovered by the first author in Canóvanas, Puerto Rico. The species name, portoricense, pays homage to the island of Puerto Rico, the locale of its discovery.
Description
The thallus, or body, of Clandestinotrema portoricense, can span up to in diameter. The thallus, which can be either thinly epiperidermal or partially endoperidermal, is white, slightly shiny, and smooth to uneven in texture. No prothallus is present in this species. The lichen's , responsible for photosynthesis, is a green alga from genus Trentepohlia, with cells that are rounded to irregular in outline and grouped together in a yellowish-green colour.
What makes this species unique are the ascomata – reproductive structures where spores are produced – that are rounded and immersed with a lateral . The are 3-septate to often somewhat , with an additional, longitudinal septum in the upper segment. They are hyaline, and with diamond-shaped .
No substances were detected in this species using thin-layer chromatography.
Similar species
While most species of Clandestinotrema have regularly (sub-)muriform ascospores, C. portoricense stands out due to its seemingly 3-septate ascospores that may form an additional, longitudinal septum in the thicker proximal segment. This characteristic differentiates it from the other species in the genus, such as C. analorenae, C. maculatum, and C. protoalbum, all of which have regularly 3-septate ascospores. Apart from its unique ascospore septation, Clandestinotrema portoricense also differs in the of the and , providing further distinguishing features.
Habitat and distribution
This lichen species was discovered in the shaded understory of a Palo Colorado forest in El Yunque National Forest, Puerto Rico, specifically on the living trunk of an unidentified tree.
References
Graphidaceae
Lichen species
Lichens described in 2014
Lichens of the Caribbean
Taxa named by Robert Lücking
Species known from a single specimen | Clandestinotrema portoricense | [
"Biology"
] | 609 | [
"Individual organisms",
"Species known from a single specimen"
] |
74,014,923 | https://en.wikipedia.org/wiki/Eli%C3%A9cer%20%C3%81vila | Eliécer Ávila Cicilia (born in 1985 in Puerto Padre, Las Tunas, Cuba) is a Cuban computer scientist and dissident. Founder and former president of the Cuban political party Somos Más. Known in Cuba for leading an incident in 2008 while he was a student at the University of Information Science (UCI), in which he asked a series of questions (according to Eliécer, "of great concern for young Cubans") to the then president of the National Assembly of Popular Power, Ricardo Alarcón de Quesada.
UCI (Universidad de Ciencias Informáticas, "University of Informatic Sciences") Incident
Students' Q&A session with Ricardo Alarcón de Quesada
Eliécer Ávila was widely known in Cuba as a result of his intervention on January 28, 2008, at the University of Information Science of Cuba (UCI), where the then president of the National Assembly of the Popular Power of Cuba, Ricardo Alarcón de Quesada, had given a round of questions and answers after a talk with computer science students. Eliécer took his turn after another student, Alejandro Rafael Hernández Real, of whose intervention the final fragment was also included in a video that was spread clandestinely within Cuba.
Eliécer asked four questions during his speech, delving into their economic and political implications, such as the quality of public transport, misinformation in the population, the rule of law of the Cuban people and the lack of Internet connectivity. The answers given by Alarcón were widely criticized by the Cuban population, both inside and outside Cuba, once the video was broadcast. It was said that Alarcón did not respond to any of the questions that were put to him, and rather addressed at length problems that existed in the period prior to 1959. Especially criticized was Alarcón's justification for regulating the departure of Cubans abroad: "If the 6 billion people in the world were allowed to travel, they would create a tremendous entanglement in the airs."
Video recordings of Eliécer's questions and Alarcón's respective answers were copied and widely disseminated hand-by-hand among the Cuban population through USB flash drives. The video also received a great deal of international attention, especially from the Cuban exile community. Several Cuban-in-exile opinion outlets have speculated that Ricardo Alarcón's political replacement in 2013 and his subsequent low profile were caused by his responses at this particular conference.
Declarations on Cuban state-run mass media
After the video had a great impact both inside and outside of Cuba, an unusual political debate arose among the Cuban population and rumors began to emerge regarding his personal situation and an alleged imprisonment and punishment for political reasons. In response to these rumors, on February 11, 2008, the state news agency Cubadebate conducted an interview with five young people who had participated in the conference with Alarcón, including Eliécer. The students interviewed denied having suffered negative repercussions from the Cuban authorities, and classified the speculation in this regard as "criminal manipulation" and "media warfare." Eliécer said he regretted that his image was the object of distortions and, like his other colleagues, clarified that his objective in asking those questions was not to question the legitimacy of the Cuban government:
In the first place [I would like] to explain that the fact that some students have exposed some issues, some controversies [...] is to better build socialism, and not to destroy it. And for the things that have to be fixed, that have to be changed, that have to be reviewed; we will do it within Revolution.
The following day, the National Newscast of the Cuban Television also broadcast a news clip that included a brief interview with Eliécer Ávila and Alejandro Rafael Hernández, where both once again denied any negative repercussions after the incident. The video recording from the Q&A session between the students and Ricardo Alarcón was never broadcast on Cuban television.
Dissidence and political activism
Interview with Estado de SATS
Eliecer Ávila made a public appearance again in 2011, 4 years after the UCI incident, in an interview with Antonio Rodiles, coordinator of the independent art and news platform Estado de SATS. During the two-hours-long interview, Eliécer commented to Rodiles that he felt "scammed by the Cuban government." Eliécer said that the attitude of the Cuban government towards him changed radically after the interview with Cubadebate in 2008. He accused the Cuban government of having sent him to work in precarious conditions at a Youth Computer Club without Internet access in his hometown municipality, Puerto Padre, and having been denied a permanent stay in Havana in retaliation for his questioning of state policies and the Minister of Culture Ricardo Alarcón de Quesada. Eliécer also said that when he was about to graduate he was sanctioned by the university for accepted to participate in an interview with an "independent journalist" (i.e., not affiliated with the Cuban state media) after the video with his questions to Alarcón became popular; although he ultimately managed to get a computer science degree.
Eliécer also said to his interviewer that, after graduating, he reflected deeply on the political situation in Cuba, which he argued was something he wasn't able to do while studying due to "lack of time and information." He criticized and accused the Communist Party of Cuba of monopolizing power, persecuting other political currents and not allowing the free discussion of ideas. He held him responsible for the poor prospects for the youth and the country's lack of prosperity, and described the Cuban electoral system as "a laughing matter" due to its vertical structure and lack of institutional transparency.
References
Cuban political people
Computer scientists
21st-century Cuban people
Cuban journalists
Cuban dissidents
1985 births
Living people | Eliécer Ávila | [
"Technology"
] | 1,201 | [
"Computer science",
"Computer scientists"
] |
74,016,321 | https://en.wikipedia.org/wiki/SenseGlove | SenseGlove is a Dutch technology company that develops and manufactures wearable hand haptic products for use in virtual reality (VR), VR/AR training, research and other applications. The company is headquartered in Delft, Netherlands.
Overview
SenseGlove develops force and haptic feedback gloves that enable to emulate natural feelings for users interacting with virtual objects. This includes the sense of its size, stiffness, and resistance.
Their products are mainly used for enterprise training in automotive, aviation, defense, healthcare and research sectors.
History
SenseGlove was initially a graduation project of its two founders, Johannes Luijten and Gijs den Butter, at the Delft University of Technology. The initial working prototype was introduced in 2017 when developers aimed to create a rehabilitation device for stroke victims. The company's first haptic force-feedback glove, SenseGlove DK1, was designed as an exoskeleton for hands that was capable of providing haptic sensations and had the functions of fingers tracking, vibrotactile feedback and force-feedback. It was mainly used for research and telerobotics applications.
In 2021, SenseGlove announced SenseGlove Nova, a new version of haptic force-feedback gloves designed for VR training purposes. It was redesigned to be wireless and more compact than DK1.
In 2022, DK1 has been used in a project that won Ana Avatar XPrize by X Prize Foundation.
In his Dope Tech review in 2022, Marques Brownlee, an American tech commentator, reviewed the SenseGlove and praised the technology behind the product. While CNET observer after testing the SenseGlove Nova commented that haptic technology is yet to become a common fixture in home VR setups.
In May 2023 SenseGlove announced the second generation of Nova – the “Nova 2.” The Nova 2 features palm feedback to simulate a feeling inside the user's hand and provide an increased level of realism in virtual training, research, and social multiplayer interactions.
Products
SenseGlove Nova is a wireless haptic glove that is able to provide force feedback (by applying resistance through its magnetic friction brakes). Its vibrotactile feedback renders the feeling of realistic button clicks, vibrations, and impact simulations.
SenseGlove Nova 2 is equipped with active contact feedback, a feature that comes in addition to force-feedback and vibrotactile-feedback which are already key features of the Nova. This function, as developers describe it, impact user's palms physically depending on the virtual objects being carried that makes one feel it even more realistic.
References
Companies of the Netherlands
Information technology
Virtual reality companies
Virtual reality accessories
Virtual reality | SenseGlove | [
"Technology"
] | 547 | [
"Information and communications technology",
"Information technology"
] |
74,016,598 | https://en.wikipedia.org/wiki/Lecanactis%20borbonica | Lecanactis borbonica is a rare species of corticolous (bark-dwelling), lichen in the family Roccellaceae. Found exclusively in Réunion, it forms a crustose thallus and is characterised by its rounded ascomata and the presence of specific chemical compounds.
Taxonomy
The lichen species Lecanactis borbonica was first formally described by lichenologists Damien Ertz and Anders Tehler. The type specimen was collected by the first author from La Réunion, south of Saint-Denis in the Roche Écrite nature reserve, at an altitude between . The species epithet borbonica refers to the historical name of Réunion, Île Bourbon.
Description
Lecanactis borbonica forms a crustose, white to pale cream thallus, which is 100–240 μm thick. The is the green algal genus Trentpohlia, with cell sizes ranging from 12 to 20 by 8–11 μm. The prothallus, a dark brown structure, is and 0.5–2 mm wide. The ascomata are brown, sessile, and rounded, with a diameter of 0.5–1.5 mm.
The thallus of Lecanactis borbonica is chemically characterised by the presence of lecanoric and lepraric acids. These lichen products are useful for distinguishing this species from other related lichens. For example, it can be distinguished from Lecanactis platygraphoides by the presence of lecanoric and lepraric acids, and the absence of schizopeltic acid and an unknown substance.
Habitat and distribution
Lecanactis borbonica has been documented only from its type collection in La Réunion, where it was found growing on bark.
References
Roccellaceae
Lichen species
Lichens described in 2011
Lichens of Réunion
Species known from a single specimen | Lecanactis borbonica | [
"Biology"
] | 395 | [
"Individual organisms",
"Species known from a single specimen"
] |
74,016,618 | https://en.wikipedia.org/wiki/Lichenopeltella%20heppiae | Lichenopeltella heppiae is a rare species of lichenicolous (lichen-dwelling) fungus in the family Lichenopeltella. It grows on the thallus and apothecia of Heppia despreauxii.
Taxonomy
Lichenopeltella heppiae was first described by Dutch lichenologist Pieter van den Boom as a new species in 2012. The type specimen was found in the Algarve region of Portugal, northeast of Albufeira, growing on Heppia despreauxii. The species name, heppiae, is derived from the host genus of the fungus.
Description
Lichenopeltella heppiae is characterized by its black, spherical ascomata that are in the form of , which measure 100 to 150 μm in diameter. The asci are cylindrical to narrowly and 8-spored, measuring 35–55 by 15–18 μm. The hyaline ascospores are clavate (club-shaped), contain a single septum, measure 14–17 by 5.5–7 μm, and feature three pairs of curved at the top.
have not been observed in Lichenopeltella heppiae. The fungus is not known to cause any damage to its host, Heppia despreauxii.
Similar species
Lichenopeltella species are generally host-specific. While Lichenopeltella heppiae shares some characteristics with other known Lichenopeltella species, it is most closely related to Lichenopeltella arctomiae. Both species have setulae at the tips of the upper cell of the ascospores; however, L. arctomiae has longer ascospores, typically measuring 17–18.6–20 by 5–5.9–6.5 μm.
Habitat and distribution
Lichenopeltella heppiae has only been found at its type locality in the Algarve region of Portugal. It grows abundantly on the terricolous (ground-dwelling) host species Heppia despreauxii in a wide, open, gently sloping area among low calcareous outcrops. Other lichens observed in the same habitat include Epiphloea terrena, Heppia echinulata, Heppia solorinoides, Squamarina cartilaginea, and Squamarina concrescens.
References
Microthyriales
Fungi of Europe
Fungi described in 2012
Lichenicolous fungi
Fungus species | Lichenopeltella heppiae | [
"Biology"
] | 520 | [
"Fungi",
"Fungus species"
] |
74,017,634 | https://en.wikipedia.org/wiki/Thioquinanthrene | Thioquinanthrene, also known as thiochinathren, is an aromatic organic chemical compound. It has the chemical formula C18H10N2S2 and reacts with alcoholates or alkoxides. One of the key uses is to act as a catalyst poison in the Rosenmund reduction. It has the IUPAC name of 2,13-dithia-10,21-diazapentacyclo[12.8.0.03,12.04,9.015,20]docosa-1(14),3(12),4,6,8,10,15,17,19,21-decaene.
Rosenmund catalyst poison
In the Rosenmeund reaction, an acid chloride is reduced to an aldehyde. Continuing the reduction produces an alcohol. This further reaction is undesirable as the alcohol will now react with the acyl chloride to produce the unwanted ester product. For this reaction (over reduction) to be prevented, the catalyst needs to be poisoned. Thioquinanthrene was used initially, although other materials have been used since.
References
Aromatic compounds
Catalysis
Heterocyclic compounds with 5 rings
Dithiins
Nitrogen heterocycles
Quinolines | Thioquinanthrene | [
"Chemistry"
] | 264 | [
"Catalysis",
"Aromatic compounds",
"Chemical kinetics",
"Organic compounds"
] |
74,018,311 | https://en.wikipedia.org/wiki/Predicted%20Aligned%20Error | The Predicted Aligned Error (PAE) is a quantitative output produced by AlphaFold, a protein structure prediction system developed by DeepMind. PAE estimates the expected positional error for each residue in a predicted protein structure if it were aligned to a corresponding residue in the true protein structure. This measurement helps scientists assess the confidence in the relative positions and orientations of different parts of the predicted protein model.
Structure
PAE is presented as a two-dimensional (2D) interactive plot where the color at coordinates (x, y) represents the predicted position error at residue x if the predicted and true structures were aligned on residue y. Lower PAE values for residue pairs from different domains suggest well-defined relative positions and orientations in the prediction, while higher PAE values indicate uncertainty in the relative positions or orientations.
Users can download the raw PAE data for all residue pairs in a custom JSON format for further analysis or visualization using a programming language such as Python. The format of the JSON file is as follows:
[
{
"predicted_aligned_error": [[0, 1, 4, 7, 9, ...], ...],
"max_predicted_aligned_error": 31.75
}
]
In the JSON file, the field predicted_aligned_error provides the PAE value for each residue pair (rounded to the nearest integer), and the field max_predicted_aligned_error gives the maximum possible PAE value, which is capped at 31.75 Å. The PAE is measured in Ångströms.
A separately developed 3D viewer of PAE allows for more intuitive visualization.
Interpretation
Interpretation of PAE values allows scientists to understand the level of confidence in the predicted structure of a protein:
Lower PAE values between residue pairs from different domains indicate that the model predicts well-defined relative positions and orientations for those domains.
Higher PAE values for such residue pairs suggest that the relative positions and/or orientations of these domains in the 3D structure are uncertain and should not be interpreted.
Caveats
Although PAE provides valuable information, users should note that it is asymmetric; the PAE value for (x, y) may differ from the value for (y, x), particularly between loop regions with highly uncertain orientations. Moreover, while AlphaFold can make useful inter-domain predictions, intra-domain prediction accuracy is expected to be more reliable based on CASP14 validation.
External links
PAE 3D viewer
References
Bioinformatics
Computer file formats | Predicted Aligned Error | [
"Engineering",
"Biology"
] | 516 | [
"Bioinformatics",
"Biological engineering"
] |
74,020,014 | https://en.wikipedia.org/wiki/Vector%20database | A vector database, vector store or vector search engine is a database that can store vectors (fixed-length lists of numbers) along with other data items. Vector databases typically implement one or more Approximate Nearest Neighbor algorithms, so that one can search the database with a query vector to retrieve the closest matching database records.
Vectors are mathematical representations of data in a high-dimensional space. In this space, each dimension corresponds to a feature of the data, with the number of dimensions ranging from a few hundred to tens of thousands, depending on the complexity of the data being represented. A vector's position in this space represents its characteristics. Words, phrases, or entire documents, as well as images, audio, and other types of data, can all be vectorized.
These feature vectors may be computed from the raw data using machine learning methods such as feature extraction algorithms, word embeddings or deep learning networks. The goal is that semantically similar data items receive feature vectors close to each other.
Vector databases can be used for similarity search, semantic search, multi-modal search, recommendations engines, large language models (LLMs), object detection, etc.
Vector databases are also often used to implement retrieval-augmented generation (RAG), a method to improve domain-specific responses of large language models. The retrieval component of a RAG can be any search system, but is most often implemented as a vector database. Text documents describing the domain of interest are collected, and for each document or document section, a feature vector (known as an "embedding") is computed, typically using a deep learning network, and stored in a vector database. Given a user prompt, the feature vector of the prompt is computed, and the database is queried to retrieve the most relevant documents. These are then automatically added into the context window of the large language model, and the large language model proceeds to create a response to the prompt given this context.
Techniques
The most important techniques for similarity search on high-dimensional vectors include:
Hierarchical Navigable Small World (HNSW) graphs
Locality-sensitive Hashing (LSH) and Sketching
Product Quantization (PQ)
Inverted Files
and combinations of these techniques.
In recent benchmarks, HNSW-based implementations have been among the best performers. Conferences such as the International Conference on Similarity Search and Applications, SISAP and the Conference on Neural Information Processing Systems (NeurIPS) host competitions on vector search in large databases.
Implementations
See also
References
External links
Machine learning
Types of databases | Vector database | [
"Engineering"
] | 512 | [
"Artificial intelligence engineering",
"Machine learning"
] |
65,458,141 | https://en.wikipedia.org/wiki/Cryopreservation%20of%20testicular%20tissue | Cryopreservation of testicular tissue is an experimental method being used to preserve fertility in pre-pubescent males, or males who cannot produce sperm, to allow them the option of having biological children.
Current first line treatment for fertility maintenance in men undergoing treatment which damages testicular tissue is cryopreservation of sperm. In boys yet to start producing sperm this is not possible, so cryopreservation of testicular tissue has been proposed as alternative therapy. This method is still experimental and not widely clinically available, and how to restore fertility with cryopreserved tissue is unknown and experimental.
Indications
One cause of infertility in males is the medical treatment used to treat cancer (chemotherapy or radiotherapy), as it can have a toxic effect on the sperm producing tissue in the testes. For prepubertal boys undergoing cancer treatment who haven’t yet begun producing sperm, preservation of sperm itself is not an option. Instead, cryopreservation of testicular tissue prior to cancer treatment can be offered to preserve fertility. This is available in a limited number of research centres. Later in life, if the affected individual decides they want biological children, their tissue can be retrieved from a tissue bank.
Another cause of male infertility is Klinefelter syndrome. This is a chromosomal abnormality (XY individual with extra X chromosomes) which causes germ cell loss early in life. Current research suggests that cryopreserving testicular tissue for prepubertal individuals can have promising results for using the tissue to produce sperm later in life, but is less likely to be effective if the testicular tissue is taken from older individuals.
In the future, cryopreservation of testicular tissue has the potential to be used to help transgender women have children. Again, in a scenario where a transgender women begins transitioning before spermarche (the beginning of sperm production, on average at 13.5 years), sperm producing tissue can be preserved instead. The sperm produced from this tissue can be used in artificial fertilisation. However, there have been no pregnancies yet reported using this method.
Procedure
For pre-pubertal boys undergoing chemotherapy, or any other treatment which may be significantly gonadotoxic, options to preserve fertility include cryopreservation of testicular tissue (TT). This procedure is ideally done before the commencement of any treatments to avoid mutagenic effects of this on the germ cells being preserved. These procedures are still experimental and clear guidelines on the restoring of fertility after cryopreservation of TT have yet to be published.
Testicular fragments are retrieved during surgery and immediately placed into a transport medium at 4 – 8 °C to reduce contamination. It is possible to freeze either whole tissue or cell suspensions from the TT extracted, although whole tissue preserves the ability to pursue both cell or tissue-based therapies in the future and is therefore more widely used. TT is then placed into cryotubes, most often containing sucrose; a non-penetrating cryoprotective agent (CPA). CPAs are added to increase membrane stability during the dehydration phase and reduce damage to the cell structure when cryopreserving tissue. Cryopreservation can either be done by slow freezing or vitrification.
Slow freezing and vitrification
Slow freezing allows the temperature of the cells and surrounding medium to be modified in a controlled way, maximising the dehydration of the cells before temperatures are reached which cause intracellular ice to form – this reduces the likelihood of damage from ice crystals. Vitrification freezes the tissue at an ‘ultrafast’ rate, using a higher concentration of CPAs to stabilise the tissue. This method allows fast cooling of the cells without mechanical disruption to the cell body.
Current challenges
Procedure
There have been numerous challenges identified in cryopreserving testicular tissue many of which are due to very little tissue being available for research and the lack of long-term studies. Testicular biopsies for cryopreservation have been performed among many research centres leading to variation in procedure and optimal procedure is yet to be determined.
Transport
After the tissue for cryopreservation is biopsied it needs to be transported. The tissue must remain viable during this process. There are many important variables such as temperature, biopsy size, transport time and storage medium. All of these may affect the future viability of the tissue but there are currently no long-term studies or optimal guidelines.
Generation of Sperm
The purpose of cryopreserving testis tissue is to generate viable sperm. There have not yet been sperm generated using human cryopreserved testis tissue so we do not know if this would be successful. We have however generated functional sperm capable of fertilising oocytes using animal models including primates.
Malignant contamination
Contamination of the testicular tissue for cryopreservation by malignant cells is a concern. In a rodent model it has been shown that if malignant cells are present in the cryopreserved tissue, it can cause relapse of the malignancy transplanted into the host. There have been methods trialled to remove the malignant cells from the tissue, but these are still only experimental and not reliable.
Genetic stability
It is important to consider the genetic stability of the gametes which will be produced following the transplantation of the cryopreserved tissue. In mouse studies there have been some epigenetic changes observed which seem to be insignificant. In human culture, epigenetic changes in methylation status of several imprinted genes were observed but the significance of this has not yet been determined.
Ethical considerations
Due to the nature of the cryopreservation of testicular tissue, ethical concerns must be eliminated before this technique can be used clinically. The experimental intervention in prepubertal boys lies a central concern with fertility preservation. Since children are involved a thorough consideration into the risks vs the benefits must be looked at. However, the lack of proven data on the efficacy of the technique raises questions of medical ethics. Additionally, structural and social ethical issues must be considered, such as the financial costs and accessibility of the procedure.
Future applications
Spermatogonial stem cell (SSC) transplantation, in vitro spermatogenesis and testicular tissue grafting are three methods in development for the fertility restoration of cryopreserved testicular tissue. Firstly, SSC transplantation, the only technique to allow natural conception to happen involves isolating testicular cells from the cryopreserved tissue in an attempt to grow the SSC number These SSCs are then transplanting into the testis where they will carry out spermatogenesis, producing sperm continuously. Testicular tissue grafting, an alternative approach involves grafting fragments of testicular tissue to homotypic or ectopic locations. Lastly, in vitro spermatogenesis is an approach which could be used in patients with malignant haematological diseases to reduce the chance of reintroducing malignant cells back into the body, this requires more research into the experimental conditions.
References
Cryopreservation
Reproduction | Cryopreservation of testicular tissue | [
"Chemistry",
"Biology"
] | 1,457 | [
"Behavior",
"Reproduction",
"Biological interactions",
"Cryopreservation",
"Cryobiology"
] |
65,458,150 | https://en.wikipedia.org/wiki/Artificial%20ovary | An artificial ovary is a potential fertility preservation treatment that aims to mimic the function of the natural ovary.
Conventional fertility preservation for females involves oocyte cryopreservation or ovarian tissue cryopreservation. However, there are drawbacks to these treatments. Oocyte cryopreservation is not possible for those with pre-pubertal cancer or premature ovarian insufficiency. Ovarian tissue cryopreservation also poses a risk of reintroducing malignant cells after cancer recovery, particular in those with previous leukaemia.
Artificial ovaries could be an effective alternative in fertility preservation. The artificial ovary aims to replicate its natural counterpart by producing oocytes and releasing steroid hormones. To date, no human oocytes have been fertilised or used to produce offspring using an artificial ovary and it is unlikely that this will occur until further research has been completed and bioethical concerns have been considered.
Ideally, the artificial ovary should contain follicles or oocytes obtained from ovarian tissue cryopreservation, as well as other ovarian cells to provide growth factors. Isolated follicles are then transplanted (either at the normal site of the ovary or elsewhere in the body) in a delivery scaffold. An ideal biocompatible scaffold would cause minimal inflammation, be suitable for neo-angiogenesis, and degrade after transplantation.
There are some limitations to artificial ovaries. From an ethical perspective, there is the issue of justice of who would qualify to receive artificial ovaries (except in autologous transplant) as there is limited availability. There is also a bioethical concerns around pre-implantation diagnosis and genetic manipulation of artificial ovaries. If a patient's own ovarian tissue is used for generating artificial ovaries, the risk of reintroducing malignancy is still present, although this risk would be lowered if only oocytes were used.
One area of future research in this field will look at the source of oocytes for artificial ovaries. There is potential for induced pluripotent stem cells (iPSCs) to be used as an alternative source to a patient's own gametes. Although this has not yet been tested with human stem cells, mice transplanted with these cells were able to successfully reproduce through in vitro maturation and fertilisation. However, human iPSCs are known to have mitochondrial DNA mutations even when isolated from healthy donors, therefore there is still more work to be done with this area.
How they are made
The ovarian tissue will undergo sequential culture steps to (hopefully) produce fertilisable mature oocytes:
Culture the cortical ovarian tissue to enhance primordial follicle (immature follicle) growth and isolate the primordial and primary follicles
Culture the growing ovarian follicles within a 3D microenvironment
Isolate and culture the immature oocytes in an attempt to produce mature oocytes which are ready for IVF or cryopreservation
Culturing of cortical ovarian tissue and isolation of follicles
A common source of ovarian tissue used comes from tissue excised from the patient prior to cancer treatment, which is then cryopreserved. The tissue is then cultured to activate the primordial follicles and allow them to develop. To isolate the follicles, a combination of enzymatic and mechanical tissue digestion has shown to be the most effective method to yield a high quantity of follicles whilst maintaining their quality. The enzymes used, liberase DH and DNase, are produced by good manufacturing practice (GMP) to fully comply with GMP guidelines to ensure future application to patients. The enzymatic digestion process is inactivated every 30 minutes and the suspension is filtered to allow fully isolated follicles to be removed and reduce unnecessary enzyme exposure which may lead to damage of their basement membrane and their death.
When recovering the isolated follicles, malignant cells may be inadvertently retrieved, which poses the risk of re-introducing malignant cells into the patient. To minimise the risk of contamination, the isolated follicles undergo a washing step which involves rinsing the follicles with fresh dissecting media, three times, to separate them from surrounding isolated cells.
Culturing the growing follicles within a 3D microenvironment
The isolated follicles are then encapsulated within a 3D matrix and cultured for up to 4 weeks. The material used has to meet biosafety and clinically compatible standards, such as adequate protection and support of the follicles and adaptability to human body temperature, if artificial ovaries are to be transplanted into a patient. Potential materials are divided into synthetic polymers and natural polymers. Synthetic polymers tend to be more predictable than natural polymers in terms of their rate of degradation and their mechanical properties can be tailored to the specific clinical requirements. Although they contain no essential molecules for cell adhesion, bioactive factors can be incorporated to stimulate this. The only synthetic polymer utilised so far has been poly(ethylene glycol), which developed immature mouse follicles into antral follicles and corpora lutea.
Natural polymers have bioactive molecules which play a role in cell adhesion, migration, proliferation and differentiation. However, they lack mechanical strength and the adaptability that synthetic polymers have. Unlike synthetic polymers, there has been a success with a wider range of natural polymers: collagen, plasma clots, fibrin, alginate and decellularized ovarian tissue.
The microenvironment of the structure should mimic that of the natural ovary, so the artificial ovary should support the follicles structurally, but also cellularly. Ovarian stromal cells are integrated into the microenvironment as they play an important role in early development of the follicles. They release various factors which positively regulate the transition of primordial follicles to primary follicles, but also release other cells which will differentiate into theca cells; those that play a supportive role for growing follicles and produce sex steroids such as androstenedione and testosterone. This can be achieved by isolating them from a second fresh ovarian biopsy once the patient has completed their cancer treatment, thus avoiding potential contamination. Endothelial cells should also be co-transported as they are key to promoting angiogenesis of the artificial ovary.
Oocyte culture
The immature oocytes are retrieved from the artificial ovary and cultured in vitro for a further 24–48 hours, allowing them to mature oocytes which are ready for IVF or vitrification (cryopreservation).
Mouse models
Initial experiments
The majority of knowledge we have about the artificial ovary has been discovered through the use of mouse models. Initial experiments in the 1990s were performed on mice that saw the grafting of preantral follicles onto an artificial ovary made with collagen. The preantral follicles were shown to undergo in vitro growth (IVG) therefore suggesting that a collagen matrix could be of good use for an artificial ovary. Despite the positive results, the growth was accompanied by atresia of antral follicles meaning that it was necessary to look for other alternatives to collagen that allowed follicle growth when the artificial ovary was implanted back into the mouse.
Natural matrices in the mouse model
Since then, a range of different natural matrices have been tested for their usefulness as an artificial ovary. Included in these are fibrin, alginate and decellularized human ovary which have shown in vitro maturation, ovary-like structure production and the production of offspring when transplanted into mice. In addition to these events being observed separately, the full process of development from the grafting of preantral follicles to the ovary through to the birth of live offspring has been demonstrated in the mouse model.
Synthetic matrices in the mouse model
In addition to these natural matrices a range of synthetic matrices have also been tested in mice. Synthetic matrices have the advantage that they can be made in bulk quantities and kept for a long time. However they do not contain biological factors needed for cell adhesion, therefore adding another layer of complexity to their creation. It is hoped that the knowledge we have gained using mouse models may one day be applied clinically, whether that be through the use of natural or synthetic matrices.
Restoration of puberty in mice
Not only have artificial ovaries shown the ability to restore fertility, they have further been linked to the complete restoration of hormone production leading to puberty. Transplantation of a human decellularized artificial ovary containing murine primary follicles has been shown to induce puberty in mice without oocytes by promoting oestradiol and inhibin B production. Mice were then shown to be able to produce viable offspring suggesting that artificial ovaries could be useful in women who have not undergone puberty.
Human models
There could be many possible applications of human artificial ovaries.
In vitro matured oocytes in IVF and cryopreservation
One emerging application of human artificial ovaries would be the use of oocytes which have undergone in vitro maturation (IVM) in IVF or cryopreservation. Oocyte retrieval followed by IVM does not require hormonal stimulation and can be a quick procedure, therefore would be advantageous in fertility preservation of cancer patients – especially where chemotherapy must start as soon as possible.
Re-transplantation of ovarian follicles grown in vitro
Another possible clinical application of human artificial ovaries is re-transplanting ovarian follicles which have been grown in vitro. In animal models, pre-antral ovarian follicles have been grown in vitro, then isolated and implanted into a biodegradable 3D artificial ovary for re-transplantation back into the animal ovary. This method has shown potential success in animal models, but in humans remains a theoretical concept for now.
Re-transplantation of ovarian tissue activated in vitro
A third possible clinical application is the re-transplantation of in vitro activated ovarian tissue. This would enable ovarian tissue to be removed from a patient, activated in vitro and then auto-transplanted into the same patient. However, this treatment is not advised for patients who have cancers that may metastasise in the ovaries (e.g. leukaemia) or those with ovarian carcinomas, due to concerns that the cancer cells may be re-implanted back into the patient. Auto-transplantation of the activated ovarian tissue into the broad ligament of the uterus, ovarian fossa or the remaining ovary can be completed by laparoscopy or mini-laparoscopy procedures. This procedure has resulted in healthy offspring being born to patients who suffered from premature ovarian insufficiency.
Future possibilities
Further research is needed to enable the procedures outlined above to become more successful. One area research is progressing in is that of the 3D printed ovary. A 3D printed microporous hydrogel scaffold could be created, into which isolated ovarian follicles could be implanted. This would support further follicular growth in vivo after transplantation. Full endocrine and reproductive ovarian function was restored in sterilised mice using this method.
See also
Artificial organs
References
Ovary | Artificial ovary | [
"Biology"
] | 2,395 | [
"Artificial organs"
] |
65,458,362 | https://en.wikipedia.org/wiki/Primordial%20germ%20cell%20migration | Primordial germ cell (PGC) migration is the process of distribution of primordial germ cells throughout the embryo during embryogenesis.
Process
Primordial germ cells are among the first lineages that are established in development and they are the precursors for gametes. It is thought that the process of primordial germ cell migration itself has been conserved rather than the specific mechanisms within it, as chemoattraction and repulsion seem to have been borrowed from blood cells, neurones, and the mesoderm. For most organisms, PGC migration starts in the posterior (back end) of the embryo.
This process is in most cases distinct from PGC proliferation, with the exception of mammals in which both processes occur at the same time. In most mammals, specification occurs first, followed by migration, and then the proliferation process begins in the gonads. PGCs interact with a wide range of cell types as they move from the epiblast to the gonads. The PGCs move passively (without the need for energy) with underlying somatic cells, cross epithelial barriers, and respond to cues from their environment during active migration. An epithelium must be crossed in many species during germ cell migration, and changes in adhesion are observed in PGCs during their exit from the endoderm and during the initiation of active migration. Active migration takes place as PGCs move towards the developing somatic gonad. Effective migration requires cell elongation and polarity. Environmental guidance cues are required for the PGCs to initiate and sustain their mobility. Specific molecular pathways are activated to give PGCs motility.
Function
One of the functions of PGC migration is to allow them to reach the gonad, where they will go on to form sperm or oocytes. However, an additional function that this migration is thought to serve is as quality control for PGCs. Migration occurs early in gametogenesis, but PGCs could contain defects that could have a negative impact on later development - genetic mutations may be acquired because of proliferation in the blastocyst. This is done via a negative selection process – PGCs that are unable to complete migration are removed and those that are able to correctly respond to migration cues are preferred. PGCs that are able to migrate the fastest and reach the gonad are more likely to colonise it and give rise to future gametes. The PGCs that go off route or don’t reach the gonad undergo programmed cell death (apoptosis). It is thought that every step after specification may function as a selective mechanism to ensure germ cells are of the highest quality. The selective mechanisms may also be important for removing PGCs with abnormal epigenetic marks and in doing so preserving the germline.
Primordial germ cell migration in invertebrates
In Drosophila, the whole migration process has been estimated to take 10 hours. It begins with the formation of PGCs; from dividing nuclei becoming encircled by cell membranes, occurring at the posterior pole of the embryo. Division of the nuclei stops once they have a cell membrane. PGCs’ transcription process is also thought to be actively subdued once formed.
In Drosophila, PGC migration begins with passive movement along the dorsal side of the embryo, during gastrulation. This is followed by more passive movement, due to the invagination of the posterior midgut primordium, which leads to the PGCs in the centre of the embryo, surrounded by epithelial cells that have been folded back on themselves. There is then a split into two groups, left and right respectively, as they actively migrate laterally across the epithelium to exit the gut, facilitated by fibroblast growth factor (FGF) signalling and a repulsion-based mechanism using enzymes encoded by the Wunen gene. This is followed by active movement dorsally along the basal side of the embryo. Through directional migration - which requires multiple genes to work, one being the Columbus (clb) gene, which codes for Drosophila HMG CoA reductase - the germ cells move towards the somatic gonadal precursor cells and associate with them. These two associated cell types then migrate together anteriorly, until they coalesce into the embryonic gonad at the future site of the mature gonad.
Primordial germ cell migration in vertebrates
In vertebrate development, the location where primordial germ cells are specified and the subsequent migratory paths that they take differs among species.
Chicken
Chicken primordial germ cells are initially specified in the area pellucida (a one-cell thick layer of epiblast lying above the sub-germinal space). Following the formation of the primitive streak, the germ cells are carried to the germinal crescent region. Unlike most model organisms where germ cell migration is predominantly via the gut epithelium, chicken PGCs migrate through the embryonic vascular epithelium. Once they have exited the capillary vessels, the final stage of migration is along the dorsal mesentery to the developing gonad.
Mice
In mice, PGCs are specified in the proximal epiblast and subsequently migrate through the primitive streak towards the endoderm. The PGCs then embed themselves within the epithelium of the hind-gut and from there will migrate towards the mesoderm via the dorsal mesentery. There is then bilateral migration of the PGCs to the developing gonadal ridges which follows a pattern very similar to that found in Drosophila.
Zebrafish
Zebrafish PGCs are specified at four different locations within the early embryo via inheritance of germ plasm (a mixture of RNA and protein often associated with mitochondria). Germ cells from these four locations will then migrate dorsally after down-regulation of the rgs14a G-protein which regulates E-cadherin. Down-regulation will result in reduced cell-cell adhesion which allows the germ cells to separate and begin the migration process. Migration of the PGCs then continues towards the developing somites 1-3. This movement is coordinated by the expression of the chemo-attractant SDF1A (stromal derived factor 1a). The final migration towards the developing gonad occurs 13 hours-post-fertilisation after which point the germ cells coalesce with the somatic gonadal precursor cells. The entire process takes around 24 hours.
Infidelity of PGCs
PGCs are described as the dedicated cells in early embryonic development, responsible for reaching the developing gonad. During their migration however, heterogeneity of cellular behaviour is observed due to change in cellular morphology from the time of specification to colonization. By the end of PGC migration, around 5% of migratory cells remain outside the gonad and later undergo apoptosis.
The apoptotic route during the migratory period is occurring via an intrinsic pathway; nonetheless, the elimination of PGCs can be unsuccessful and result in tumour formation known as teratomas, derivatives of the three germ layers. Mutations in Pten, CyclinD1, Dmrt1 and Dnd1 oncogenes in mice resulted in testicular teratomas, and variants are related with the same tumours in humans. Tumour formation (neoplasm) from foetal gonocytes suggests that they are incapable of maintaining proliferative arrest and resistance to further differentiation.
Even so, the origin of these teratomas could be distinct from the PGCs failing in migration. Extragonadal germ cell tumours (GCTs) evolve due to a lesion along the midline of the body, prior to the migratory PGCs movement through the hindgut and the medial mesentery to the gonads. Therefore, human GCTs originate from early embryo stem cells and the germ line, and unlike most tumours they seldom have somatic mutations, but instead are driven by unsuccessful control of their developmental potential, resulting in their reprogramming.
References
Cells
Developmental biology | Primordial germ cell migration | [
"Biology"
] | 1,671 | [
"Behavior",
"Developmental biology",
"Reproduction"
] |
65,458,823 | https://en.wikipedia.org/wiki/Resumption%20of%20meiosis | Resumption of meiosis occurs as a part of oocyte meiosis after meiotic arrest has occurred. In females, meiosis of an oocyte begins during embryogenesis and will be completed after puberty. A primordial follicle will arrest, allowing the follicle to grow in size and mature. Resumption of meiosis will resume following an ovulatory surge (ovulation) of luteinising hormone (LH).
Meiotic arrest
Meiosis was initially discovered by Oscar Hertwig in 1876 as he examined the fusion of the gametes in sea urchin eggs. In 1890, August Weismann, concluded that two different rounds of meiosis are required and defined the difference between somatic cells and germ cells.
Studies regarding meiotic arrest and resumption have been difficult to attain because, within females, the oocyte is inaccessible. The majority of research was conducted by removing the follicles and artificially maintaining the oocyte in meiotic arrest. Despite this allowing the gain of knowledge on meiosis in oocytes, the results of this methodology may be difficult to interpret and apply to humans.
During oogenesis, meiosis arrests twice. The main arrest occurs during the diplotene stage of prophase 1, this arrest lasts until puberty. The second meiotic arrest then occurs after ovulation during metaphase 2 and lasts for a much shorter time than the first arrest. Meiotic arrest occurs mainly due to increased cAMP levels in the oocyte, which regulates key regulator cyclin kinase complex maturation promoting factor (MPF). cGMPs produced by somatic follicular cells further regulate cAMP concentration in the oocyte.
Meiotic resumption in mammals
Meiotic resumption is visually manifested as “germinal vesicle breakdown” (GVBD), referring to the primary oocyte nucleus. GVBD is the process of nuclear envelope dissolution and chromosome condensation similar to mitotic prophase.
In females, the process of folliculogenesis begins during fetal development. Folliculogenesis is the maturation of ovarian follicles. Primordial germ-cells (PGC’S) undergo meiosis leading to the formation of primordial follicles. At birth, meiosis arrests at the diplotene phase of prophase I. Oocytes will remain in this state until the time of puberty. At the time of ovulation a surge of LH initiates the resumption of meiosis and oocytes enter the second cycle, which is known as oocyte maturation. Meiosis is then arrested again during metaphase 2 until fertilisation. At fertilisation meiosis then resumes which results in the disassociation from the 2nd polar body, meaning maturation of the oocyte is now complete.
Meiotic resumption signalling
Cyclic adenosine monophosphate levels (cAMP)
Elevated concentrations of intra-oocyte cAMP regulates meiotic arrest and prevents meiotic resumption. Intracellular cAMP constantly activates PKA, which then activates nuclear kinase Weel/MtyI. Weel/Mtyl inhibits cell division cycle 25B (CDC25B) which is a main activator for Cyclin-dependent kinase (CDK). This leads to the inactivation of maturation promoting factor (MPF) as MPF comprises CDK and Cyclin B.
MPF is an essential regulator for M-phase transition and plays a key role in meiotic resumption in oocytes and its post-GVBD activities. Hence, a high level of cAMP indirectly inactivates MPF, preventing meiotic resumption.
GPCR3-Gs-ADCY Cascade
The production of cAMP is maintained by the intra-oocyte GPCR-GS-ADCY cascade.
Inhibition of Gs protein in mouse oocyte leads to meiotic resumption. Gs protein-coupled receptor 3 (GPCR3) KO mice was found to present with spontaneous meiotic resumption as well, which was preventable with the administration of GPCR3 RNA into the oocyte. GPCR3 can be found to be present in the oocyte membrane and functions to sustain a minimal level of cAMP, preventing meiotic resumption.
In the oocyte, the effector enzyme of GPR is adencylate cyclase (ADCY). It acts as a catalyst converting adenosine triphosphate (ATP) to cAMP, maintaining cAMP levels within the oocyte, preventing meiotic resumption.
Somatic follicular cells and cyclic guanosine monophosphate (cGMP)
The removal of oocyte from the follicle results in spontaneous meiotic resumption which implicates the role of somatic follicular cells in meiotic arrest.
cGMP is produced by guanylyl cyclase present the granulosa cells, in particular, natriuretic peptide receptor 2 (NPR2) and natriuretic peptide precursor-C (NPPC) that can be found in the cumulus and mural granulosa cells respectively (in mice, pigs and human).
cGMP produced by these granulosa cells rapidly diffuse into the oocyte through gap junctions and inhibits cAMP-phosphodiesterase 3A (cAMP-PDE3A). cAMP-PDE3A functions as a catalyst for the breakdown of cAMP to AMP within the oocyte. Hence, somatic follicular cells produce cGMP inhibit cell resumption via maintain intra-oocyte cAMP levels.
Inosine 5’ monophosphate (IMP) dehydrogenase (IMPDH)
Previous studies have demonstrated that treatment of mouse oocytes with IMPDH inhibitors induced gonadotropin-independent meiotic resumption in vivo.
IMPDH is a rate limiting enzyme that catalyses IMP to xanthosine monophosphate (XMP). It can induce meiotic resumption as XMP produced is ultimately converted to cGMP through a series of enzymatic activities.
In addition, IMPDH maintains hypoxanthine (HX) levels in the follicular fluid. The HX concentration inhibits cAMP-PDE activity in vitro.
Lutensing Hormone (LH)
It is commonly known that monthly surge of preovulatory LH from the pituitary gland promotes meiotic resumption.
First, LH signaling dephosphorylates and inactivates NPR2 guanylyl cyclase. This results in a rapid decrease in cGMP levels in the granulosa cells and the oocytes through the gap junctions. PDE5 is also activated, increasing cGMP hydrolysis. In mouse follicles, the concentration of cGMP drops from ~2-5 μM to ~100nM within a minute from exposure to LH.
The decreasing cGMP concentration occurs in a sequential fashion, from the mural granulosa cells, the cumulus granulosa cells and finally the oocyte. The diffusion of cGMP out of the oocyte promotes meiotic resumption. It proposed that the diffusion of cGMP away from the oocyte occurs before LH-induced closure of gap junctions between somatic cells, could be an “augment step to further guarantee a low level of cGMP within the oocyte or cumulus granulosa”.
It is also believed that LH-induced cGMP decrease in granulosa cells is only part of the mechanism, with the full mechanism remaining unexplained.
Further reading
Essential Reproduction. Martin H. Johnson. Chichester; Hoboken, N.J.: Wiley-Blackwell; 2013; 7th edition
Developmental Biology. Michael J F Barresi, Scott F Gilbert. Sinauer Associates Is an Imprint of Oxford University Press; 12th ed. edition.
References
Meiosis | Resumption of meiosis | [
"Biology"
] | 1,674 | [
"Molecular genetics",
"Meiosis",
"Cellular processes"
] |
65,460,149 | https://en.wikipedia.org/wiki/Ovorubin | Ovorubin (PcOvo or PcPV1) is the most abundant perivitellin (>60 % total protein) of the perivitelline fluid from Pomacea canaliculata snail eggs. This glyco-lipo-caroteno protein complex is a approx. 300 kDa multimer of a combination of multiple copies of six different ~30 kDa subunits.
Together with the other perivitellins from Pomacea canaliculata eggs, ovorubin serves a nutrient source for developing embryos, notably to the intermediate and late stages. Moreover, after hatching, the protein is still detected in the lumen of the digestive gland ready to be endocytosed, therefore, acting as a nutrient source for the newly hatched snail.
Ovorubin contains carbohydrates and carotenoid pigments as main prosthetic groups, which are related to many physiological roles on Pomacea aerial egg-laying strategy. Given that carbohydrates tend to retain water, the high glycosylation of ovorubin (~17 % w/w) was proposed as an embryo defense against water loss. The carotenoid pigments stabilized by ovorubin also provide the eggs of antioxidant and photoprotective capacities, crucial roles to cope with the harsh conditions of the aerial environment. The presence of carotenoid pigments is also responsible for the brightly reddish coloration of Ovorubin, and therefore snail eggs, which was related to a warning coloration (aposematism) advertising predators about the presence of deterrents. In fact, field evidence of egg unpalatability is provided by the fact that most animals foraging in habitats where the apple snails live ignore these eggs.
Like most other studied perivitellins from Pomacea snails, ovorubin is highly stable in a wide range of pH values and withstands gastrointestinal digestion, characteristics associated with an antinutritive defense system that deters predation by lowering the nutritional value of the eggs.
References
Proteins | Ovorubin | [
"Chemistry"
] | 437 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
65,461,406 | https://en.wikipedia.org/wiki/Peter%20Harzem | Peter Harzem (January 5, 1930 – May 26, 2008) was a Turkish-American psychologist who specialised in the field of behavior analysis.
Life
Peter Harzem was born in Istanbul, Turkey, on January 5, 1930. His parents were Sukru and Saime Harzem. He initially worked as a newspaper reporter.
After the war he moved to London to complete his education. He was awarded a BSc Psychology from the University of London. He was strongly influenced by Harry Hurwitz who had established an operant laboratory at Birkbeck College. Harzem conducted a student project in this laboratory.
He then moved to the University College of North Wales which later became Bangor University where he completed his PhD and obtained a faculty position.
He moved to the United States in 1978 where he became Hudson Professor of Psychology at Auburn University, Alabama.
He died on May 26, 2008.
Work
Harzem established a reputation for his work on behaviour analysis. At Bangor University, he published an influential volume (Harzem & Miles, 1978). He was also concerned with the role of language. In his later years he became interested in what he termed the discrediting of John B. Watson (Harzem, 1993; 2001). Following on from Hurwitz, Harzen had a continuing interest in the nature of science (Harzem, 2007).
Positions
Associate editor, Journal of the Experimental Analysis of Behavior.
Publications
Harzem P. (2007). A brief history of knowledge: Science and non-science in the understanding of human nature. In: Ribes-Inesta E, Burgos J.E, editors. Knowledge, cognition, and behavior: Proceedings of the ninth Biannual Symposium on the Science of Behavior. Guadalajara, Mexico: Universidad de Guadalajara. pp. 11–30.
Harzen, P.E. (2004). Behaviorism for new psychology: What was wrong with behaviorism and what is wrong with it now. Behavior and Philosophy, 32, 5–12.
Harzen, P.E. (2001). The Intellectual Dismissal of John B. Watson: Notes on a Dark Cloud in the History of the Psychological Sciences. Behavioral Development Bulletin, 10(1), 15–16.
Harzem, P. (1993). The discrediting of John Broadus Watson. Mexican Journal of Behavior Analysis, 19, 39–66.
Zeiler M.D, Harzem P. (Eds.) (1983). Biological factors in learning. New York: Wiley.
Harzem, P.E. (Ed.)(1981). Predictability, Correlation, and Contiguity New York: Wiley
Zeiler M.D, Harzem P. (Eds.) (1979). Reinforcement and the organization of behavior. New York: Wiley.
Harzem, P.E., & Miles, T.R. (1978) Conceptual Issues In Operant Psychology. Chichester: Wiley.
References
1930 births
2008 deaths
Health professionals from Istanbul
Turkish psychologists
Turkish emigrants to the United States
20th-century American psychologists
Behaviourist psychologists
Alumni of Bangor University
Auburn University faculty | Peter Harzem | [
"Biology"
] | 652 | [
"Behaviourist psychologists",
"Behavior",
"Behaviorism"
] |
65,462,225 | https://en.wikipedia.org/wiki/List%20of%20pteridophytes%20of%20South%20Africa | This listing contains taxa of plants in the division Pteridophyta, recorded from South Africa. A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden. Ferns, horsetails (often treated as ferns), and lycophytes (clubmosses, spikemosses, and quillworts) are all pteridophytes. However, they do not form a monophyletic group because ferns (and horsetails) are more closely related to seed plants than to lycophytes. "Pteridophyta" is thus no longer a widely accepted taxon, but the term pteridophyte remains in common parlance, as do pteridology and pteridologist as a science and its practitioner, respectively. Ferns and lycophytes share a life cycle and are often collectively treated or studied, for example by the International Association of Pteridologists and the Pteridophyte Phylogeny Group.
23,420 species of vascular plant have been recorded in South Africa, making it the sixth most species-rich country in the world and the most species-rich country on the African continent. Of these, 153 species are considered to be threatened. Nine biomes have been described in South Africa: Fynbos, Succulent Karoo, desert, Nama Karoo, grassland, savanna, Albany thickets, the Indian Ocean coastal belt, and forests.
The 2018 National Biodiversity Assessment plant checklist lists 35,130 taxa in the phyla Anthocerotophyta (hornworts (6)), Anthophyta (flowering plants(33534)), Bryophyta (mosses (685)), Cycadophyta (cycads (42)), Lycopodiophyta (Lycophytes(45)), Marchantiophyta (liverworts (376)), Pinophyta (conifers (33)), and Pteridophyta {cryptograms(408)).
Listing
Abrodictyum pseudorigidum Bauret & Dubuisson, indigenous
Acrostichum aureum L. indigenous
Actiniopteris dimorpha Pic.Serm. indigenous
Actiniopteris dimorpha Pic.Serm. subsp. dimorpha indigenous
Actiniopteris radiata (J.Konig ex Sw.) Link, indigenous
Adiantum aethiopicum L. indigenous
Adiantum capillus-veneris L. indigenous
Adiantum hispidulum Sw. indigenous
Adiantum hispidulum Sw. var. hispidulum indigenous
Adiantum incisum Forssk. indigenous
Adiantum lunulatum Burm.f. indigenous
Adiantum poiretii Wikstr. indigenous
Adiantum raddianum C.Presl
Alsophila capensis (L.f.) J.Sm. indigenous
Alsophila dregei (Kunze) R.M.Tryon, indigenous
Amauropelta bergiana (Schltdl.) Holttum, indigenous
Amauropelta bergiana (Schltdl.) Holttum var. bergiana, indigenous
Amauropelta knysnaensis (N.C.Anthony & Schelpe) Parris, endemic
Amauropelta oppositiformis (C.Chr.) Holttum, indigenous
Ampelopteris prolifera (Retz.) Copel. indigenous
Anemia dregeana Kunze, indigenous
Anemia simii Tardieu, indigenous
Anogramma leptophylla (L.) Link, indigenous
Arachniodes foliosa (C.Chr.) Schelpe
Arachniodes webbiana (A.Braun) Schelpe, indigenous
Arachniodes webbiana (A.Braun) Schelpe subsp. foliosa (C.Chr.) Gibby, Rasbach, Reichst., Widen & Via, indigenous
Arthropteris monocarpa (Cordem.) C.Chr. indigenous
Aspidium athamanticum Kunze, indigenous
Aspidium falcatum (L.f.) Sw.
Aspidium inaequale Schltdl. indigenous
Aspidium inaequale Schltdl. var. montanum Kunze, indigenous
Aspidium pentagonum (T.Moore) Kuhn, indigenous
Aspidium squamisetum (Hook.) Kuhn, indigenous
Asplenium adiantum-nigrum L. indigenous
Asplenium adiantum-nigrum L. var. adiantum-nigrum indigenous
Asplenium adiantum-nigrum L. var. solidum (Kunze) J.P.Roux, endemic
Asplenium aethiopicum (Burm.f.) Bech. indigenous
Asplenium aethiopicum (Burm.f.) Bech. subsp. dodecaploideum A.F.Braithw. indigenous
Asplenium aethiopicum (Burm.f.) Bech. subsp. filare (Forssk.) A.F.Braithw. indigenous
Asplenium aethiopicum (Burm.f.) Bech. subsp. tripinnatum (Baker) A.F.Braithw. indigenous
Asplenium anisophyllum Kunze, indigenous
Asplenium blastophorum Hieron. indigenous
Asplenium boltonii Hook. ex Brause & Hieron. indigenous
Asplenium capense (Kunze) Bir, Fraser-Jenk. & Lovis, indigenous
Asplenium christii Hieron. indigenous
Asplenium cordatum (Thunb.) Sw. indigenous
Asplenium dregeanum Kunze indigenous
Asplenium erectum Bory ex Willd. indigenous
Asplenium erectum Bory ex Willd. var. erectum, indigenous
Asplenium erectum Bory ex Willd. var. usambarense (Hieron.) Schelpe, indigenous
Asplenium friesiorum C.Chr. indigenous
Asplenium gemmiferum Schrad. indigenous
Asplenium hypomelas Kuhn, indigenous
Asplenium inaequilaterale Bory ex Willd. indigenous
Asplenium lividum Mett. ex Kuhn, indigenous
Asplenium lobatum Pappe & Rawson, indigenous
Asplenium lobatum Pappe & Rawson var. lobatum, indigenous
Asplenium lobatum Pappe & Rawson var. pseudo-abyssinicum N.C.Anthony & Schelpe, indigenous
Asplenium lunulatum Sw. indigenous
Asplenium monanthes L. indigenous
Asplenium multiforme Krasser, indigenous
Asplenium obscurum Blume, indigenous
Asplenium phillipsianum (Kummerle) Bir, Fraser-Jenk. & Lovis, indigenous
Asplenium platyneuron (L.) Britten, Sterns & Poggenb. indigenous
Asplenium preussii Hieron. ex Brause, indigenous
Asplenium prionitis Kunze, indigenous
Asplenium protensum Schrad. indigenous
Asplenium rutifolium (P.J.Bergius) Kunze, indigenous
Asplenium sandersonii Hook. indigenous
Asplenium schelpei A.F.Braithw. indigenous
Asplenium simii A.F.Braithw. & Schelpe, indigenous
Asplenium splendens Kunze, indigenous
Asplenium splendens Kunze subsp. drakensbergense A.F.Braithw. near endemic
Asplenium splendens Kunze subsp. splendens, indigenous
Asplenium stoloniferum Bory, indigenous
Asplenium theciferum (Humb., Bonpl. & Kunth) Mett. indigenous
Asplenium theciferum (Humb., Bonpl. & Kunth) Mett. var. concinnum (Schrad.) Schelpe, indigenous
Asplenium trichomanes L. indigenous
Asplenium trichomanes L. subsp. quadrivalens D.E.Mey. indigenous
Asplenium varians Wall. ex Hook. & Grev. indigenous
Asplenium varians Wall. ex Hook. & Grev. subsp. fimbriatum (Kunze) Schelpe, indigenous
Asplenium x flexuosum Schrad. indigenous
Athyrium crassicaule J.P.Roux, near endemic
Athyrium newtonii Baker, indigenous
Athyrium schimperi Moug. ex Fee, indigenous
Azolla cristata Kaulf. invasive
Azolla filiculoides Lam. invasive
Azolla microphylla Kaulf.
Azolla pinnata R.Br. indigenous
Azolla pinnata R.Br. subsp. africana (Desv.) R.M.K.Saunders & K.Fowler, indigenous
Azolla pinnata R.Br. subsp. asiatica R.M.K.Saunders & K.Fowler, invasive
Blechnum attenuatum (Sw.) Mett. indigenous
Blechnum attenuatum (Sw.) Mett. var. giganteum (Kaulf.) Bonap.
Blechnum australe L. indigenous
Blechnum australe L. subsp. australe, indigenous
Blechnum capense Burm.f. indigenous
Blechnum inflexum (Kunze) Kuhn, indigenous
Blechnum punctulatum Sw. indigenous
Blechnum punctulatum Sw. var. atherstonei (Pappe & Rawson) Sim, indigenous
Blechnum punctulatum Sw. var. intermedium (Sim) Sim, endemic
Blechnum punctulatum Sw. var. krebsii (Kunze) Sim, endemic
Blechnum punctulatum Sw. var. punctulatum, indigenous
Blechnum tabulare (Thunb.) Kuhn, indigenous
Blotiella glabra (Bory) R.M.Tryon, indigenous
Blotiella natalensis (Hook.) R.M.Tryon, indigenous
Bolbitis heudelotii (Bory ex Fee) Alston, indigenous
Cephalomanes rigidum (Sw.) K.Iwats. indigenous
Ceratopteris thalictroides (L.) Brongn. indigenous
Ceterach cordatum (Thunb.) Desv. indigenous
Cheilanthes bergiana Schltdl. indigenous
Cheilanthes botswanae Schelpe & N.C.Anthony, indigenous
Cheilanthes buchananii (Baker) Domin, indigenous
Cheilanthes capensis (Thunb.) Sw. indigenous
Cheilanthes ceterachoides A.W.Klopper & Klopper, endemic
Cheilanthes contracta (Kunze) Mett. ex Kuhn, endemic
Cheilanthes deltoidea Kunze, indigenous
Cheilanthes deltoidea Kunze subsp. deltoidea, indigenous
Cheilanthes deltoidea Kunze subsp. silicicola Klopper & A.E.van Wyk, endemic
Cheilanthes depauperata Baker, endemic
Cheilanthes dolomiticola (Schelpe) Schelpe & N.C.Anthony, indigenous
Cheilanthes eckloniana (Kunze) Mett. indigenous
Cheilanthes hastata (L.f.) Kunze, indigenous
Cheilanthes hirta Sw. indigenous
Cheilanthes hirta Sw. var. brevipilosa W.Jacobsen & N.Jacobsen forma brevipilosa, indigenous
Cheilanthes hirta Sw. var. brevipilosa W.Jacobsen & N.Jacobsen forma laxa, indigenous
Cheilanthes hirta Sw. var. brevipilosa W.Jacobsen & N.Jacobsen forma waterbergensis, endemic
Cheilanthes hirta Sw. var. hirta, indigenous
Cheilanthes hirta Sw. var. hyaloglandulosa (W.Jacobsen & N.Jacobsen) J.E.Burrows, indigenous
Cheilanthes hirta Sw. var. inferacampestris W.Jacobsen & N.Jacobsen, indigenous
Cheilanthes hirta Sw. var. nemorosa W.Jacobsen & N.Jacobsen, indigenous
Cheilanthes hyaloglandulosa W.Jacobsen & N.Jacobsen, indigenous
Cheilanthes inaequalis (Kunze) Mett. indigenous
Cheilanthes inaequalis (Kunze) Mett. var. buchananii (Baker) Schelpe, indigenous
Cheilanthes induta Kunze, endemic
Cheilanthes involuta (Sw.) Schelpe & N.C.Anthony, indigenous
Cheilanthes involuta (Sw.) Schelpe & N.C.Anthony var. involuta, indigenous
Cheilanthes involuta (Sw.) Schelpe & N.C.Anthony var. obscura (N.C.Anthony) N.C.Anthony, indigenous
Cheilanthes kunzei Mett. indigenous
Cheilanthes marlothii (Hieron.) Domin, indigenous
Cheilanthes multifida (Sw.) Sw. indigenous
Cheilanthes multifida (Sw.) Sw. subsp. lacerata N.C.Anthony & Schelpe, indigenous
Cheilanthes multifida (Sw.) Sw. var. multifida, indigenous
Cheilanthes namaquensis (Baker) Schelpe & N.C.Anthony, indigenous
Cheilanthes nielsii W.Jacobsen, indigenous
Cheilanthes parviloba (Sw.) Sw. indigenous
Cheilanthes pentagona Schelpe & N.C.Anthony, indigenous
Cheilanthes quadripinnata (Forssk.) Kuhn, indigenous
Cheilanthes rawsonii (Pappe) Mett. ex Kuhn, indigenous
Cheilanthes robusta (Kunze) R.M.Tryon, indigenous
Cheilanthes viridis (Forssk.) Sw. indigenous
Cheilanthes viridis (Forssk.) Sw. var. glauca (Sim) Schelpe & N.C.Anthony, indigenous
Cheilanthes viridis (Forssk.) Sw. var. macrophylla (Kunze) Schelpe & N.C.Anthony, indigenous
Cheilanthes viridis (Forssk.) Sw. var. viridis, indigenous
Christella altissima Holttum, endemic
Christella buchananii (Schelpe) J.P.Roux, indigenous
Christella chaseana (Schelpe) Holttum, indigenous
Christella dentata (Forssk.) Brownsey & Jermy, indigenous
Christella gueinziana (Mett.) Holttum, indigenous
Christella hispidula (Decne.) Holttum, indigenous
Crepidomanes borbonicum (Bosch) J.P.Roux, indigenous
Crepidomanes inopinatum (Pic.Serm.) J.P.Roux, indigenous
Crepidomanes melanotrichum (Schltdl.) J.P.Roux, indigenous
Ctenitis lanuginosa (Willd. ex Kaulf.) Copel. indigenous
Cyathea capensis (L.f.) Sm. indigenous
Cyathea cooperi (Hook. ex F.Muell.) Domin.
Cyathea dregei Kunze, indigenous
Cyclosorus guenzianus (Mett.) J.P.Roux, indigenous
Cyclosorus interruptus (Willd.) H.Ito, indigenous
Cyrtomium falcatum (L.f.) C.Presl
Cyrtomium luctuosum J.P.Roux, indigenous
Cyrtomium pseudocaryotideum J.P.Roux, endemic
Cystopteris fragilis (L.) Bernh. indigenous
Cystopteris fragilis (L.) Bernh. subsp. fragilis, indigenous
Davallia chaerophylloides (Poir.) Steud. indigenous
Davallia denticulata (Burm.f.) Mett. ex Kuhn, indigenous
Davallia denticulata (Burm.f.) Mett. ex Kuhn var. denticulata, indigenous
Deparia japonica (Thunb.) M.Kato, invasive
Dicksonia antarctica Labill. cultivated
Dicranopteris linearis (Burm.f.) Underw. indigenous
Dicranopteris linearis (Burm.f.) Underw. var. linearis, indigenous
Didymochlaena truncatula (Sw.) J.Sm. indigenous
Didymoglossum erosum (Willd.) Beentje, indigenous
Didymoglossum reptans (Sw.) C.Presl, indigenous
Diplazium esculentum (Retz.) Sw. invasive
Diplazium zanzibaricum (Baker) C.Chr. indigenous
Doodia caudata (Cav.) R.Br.
Doryopteris concolor (Langsd. & Fisch.) Kuhn, indigenous
Doryopteris pilosa (Poir.) Kuhn, indigenous
Doryopteris pilosa (Poir.) Kuhn var. gemmifera J.E.Burrows & S.E.Strauss, indigenous
Dryopteris antarctica (Baker) C.Chr. indigenous
Dryopteris athamantica (Kunze) Kuntze, indigenous
Dryopteris buchananii (Baker) Kuntze, indigenous
Dryopteris callolepis C.Chr. indigenous
Dryopteris dracomontana Schelpe & N.C.Anthony, indigenous
Dryopteris esterhuyseniae Schelpe & N.C.Anthony, endemic
Dryopteris falcata (L.f.) Kuntze
Dryopteris inaequalis (Schltdl.) Kuntze, indigenous
Dryopteris lewalleana Pic.Serm. indigenous
Dryopteris pentheri (Krasser) C.Chr. indigenous
Dryopteris pentheri (Krasser) C.Chr. var. montana (Kunze) Alston, indigenous
Dryopteris squamiseta (Hook.) Kuntze, indigenous
Elaphoglossum acrostichoides (Hook. & Grev.) Schelpe, indigenous
Elaphoglossum angustatum (Schrad.) Hieron. indigenous
Elaphoglossum aubertii (Desv.) T.Moore, indigenous
Elaphoglossum conforme (Sw.) J.Sm. indigenous
Elaphoglossum drakensbergense Schelpe, near endemic
Elaphoglossum hybridum (Bory) Brack. indigenous
Elaphoglossum macropodium (Fee) T.Moore, indigenous
Elaphoglossum petiolatum (Sw.) Urb. var. rupestre (Sim) Sim, indigenous
Elaphoglossum spathulatum (Bory) T.Moore, indigenous
Elaphoglossum spathulatum (Bory) T.Moore var. spathulatum, indigenous
Equisetum hyemale L. invasive
Equisetum ramosissimum Desf. indigenous
Equisetum ramosissimum Desf. subsp. ramosissimum, indigenous
Gleichenia polypodioides (L.) Sm. indigenous
Gleichenia umbraculifera (Kunze) T.Moore, indigenous
Grammitis poeppigiana (Mett.) Pic.Serm. indigenous
Grammitis rigescens (Bory ex Willd.) Lellinger
Histiopteris incisa (Thunb.) J.Sm. indigenous
Hymenophyllum aeruginosum (Poir.) Carmich. indigenous
Hymenophyllum capense Schrad. indigenous
Hymenophyllum capillare Desv. indigenous
Hymenophyllum capillare Desv. var. alternialatum (Pic.Serm.) Faden, indigenous
Hymenophyllum marlothii Brause, indigenous
Hymenophyllum peltatum (Poir.) Desv. indigenous
Hymenophyllum tunbridgense (L.) Sm. indigenous
Hypodematium crenatum (Forssk.) Kuhn, indigenous
Hypolepis sparsisora (Schrad.) Kuhn, indigenous
Hypolepis villosa-viscida (Thouars) Tardieu, indigenous
Lastrea athamantica (Kunze) T.Moore, indigenous
Lastrea buchananii (Baker) Bedd., indigenous
Lastrea inaequalis (Schltdl.) C.Presl, indigenous
Lastrea pentagona T.Moore, indigenous
Lastrea plantii T.Moore, indigenous
Lepisorus excavatus (Bory ex Willd.) Ching, indigenous
Lepisorus schraderi (Mett.) Ching, indigenous
Lindsaea ensifolia Sw. indigenous
Loxogramme abyssinica (Baker) M.G.Price, indigenous
Lunathyrium japonicum (Thunb.) Sa.Kurata,
Lygodium japonicum (Thunb.) Sw.
Lygodium kerstenii Kuhn, indigenous
Lygodium microphyllum (Cav.) R.Br. indigenous
Macrothelypteris torresiana (Gaudich.) Ching
Marattia fraxinea Sm. indigenous
Marattia fraxinea Sm. var. salicifolia (Schrad.) C.Chr. indigenous
Marsilea aegyptiaca Willd. indigenous
Marsilea apposita Launert, indigenous
Marsilea burchellii (Kunze) A.Braun, indigenous
Marsilea capensis A.Braun, indigenous
Marsilea coromandelina Willd. indigenous
Marsilea ephippiocarpa Alston, indigenous
Marsilea farinosa Launert, indigenous
Marsilea farinosa Launert subsp. arrecta J.E.Burrows, indigenous
Marsilea farinosa Launert subsp. farinosa, indigenous
Marsilea fenestrata Launert, indigenous
Marsilea macrocarpa C.Presl, indigenous
Marsilea minuta L. indigenous
Marsilea minuta L. var. minuta, indigenous
Marsilea mutica Mett.
Marsilea nubica A.Braun, indigenous
Marsilea schelpeana Launert, endemic
Marsilea villifolia Bremek. & Oberm. ex Alston & Schelpe, indigenous
Megalastrum lanuginosum (Willd. ex Kaulf.) Holttum, indigenous
Melpomene flabelliformis (Poir.) A.R.Sm. & R.C.Moran, indigenous
Microgramma mauritiana (Willd.) Tardieu, indigenous
Microlepia speluncae (L.) T.Moore, indigenous
Microsorum ensiforme (Thunb.) Schelpe, indigenous
Microsorum pappei (Mett. ex Kuhn) Tardieu, indigenous
Microsorum punctatum (L.) Copel. indigenous
Microsorum scandens (G.Forst.) Tindale
Microsorum scolopendria (Burm.f.) Copel. indigenous
Mohria caffrorum (L.) Desv. endemic
Mohria caffrorum (L.) Desv. var. ferruginea J.E.Burrows & S.M.Burrows
Mohria hirsuta J.P.Roux
Mohria marginalis (Savigny) J.P.Roux, indigenous
Mohria nudiuscula J.P.Roux, indigenous
Mohria rigida J.P.Roux, indigenous
Mohria saxatilis J.P.Roux, endemic
Mohria vestita Baker, indigenous
Nephrodium antarcticum Baker, indigenous
Nephrodium athamanticum (Kunze) Hook. indigenous
Nephrodium buchananii Baker, indigenous
Nephrodium inaequale (Schltdl.) Hook. indigenous
Nephrodium squamisetum Hook. indigenous
Nephrolepis biserrata (Sw.) Schott indigenous
Nephrolepis cordifolia (L.) C.Presl
Nephrolepis cordifolia (L.) C.Presl var. cordifolia indigenous
Nothoperanema squamiseta (Hook.) Ching indigenous
Oleandra distenta Kunze, indigenous
Ophioglossum bergianum Schltdl. endemic
Ophioglossum caroticaule J.E.Burrows, indigenous
Ophioglossum convexum J.E.Burrows, indigenous
Ophioglossum costatum R.Br. indigenous
Ophioglossum gomezianum Welw. ex A.Braun, indigenous
Ophioglossum gracile Pocock ex J.E.Burrows, endemic
Ophioglossum gracillimum Welw. ex Hook. & Baker, indigenous
Ophioglossum lusoafricanum Welw. ex Prantl, indigenous
Ophioglossum nudicaule L.f. endemic
Ophioglossum polyphyllum A.Braun, indigenous
Ophioglossum polyphyllum A.Braun var. angustifolium Pocock ex J.E.Burrows, indigenous
Ophioglossum polyphyllum A.Braun var. polyphyllum, indigenous
Ophioglossum reticulatum L. indigenous
Ophioglossum rubellum Welw. ex A.Braun, indigenous
Ophioglossum vulgatum L. indigenous
Ophioglossum vulgatum L. subsp. africanum Pocock ex J.E.Burrows var. africanum, indigenous
Ophioglossum vulgatum L. subsp. kilimandscharicum (Hieron.) J.E.Burrows, indigenous
Osmunda regalis L. indigenous
Pellaea boivinii Hook. indigenous
Pellaea boivinii Hook. var. boivinii, indigenous
Pellaea calomelanos (Sw.) Link, indigenous
Pellaea calomelanos (Sw.) Link var. calomelanos, indigenous
Pellaea calomelanos (Sw.) Link var. leucomelas (Mett. ex Kuhn) J.E.Burrows, indigenous
Pellaea dura (Willd.) Hook. indigenous
Pellaea dura (Willd.) Hook. var. dura, indigenous
Pellaea leucomelas (Mett. ex Kuhn) Baker, endemic
Pellaea pectiniformis Baker, indigenous
Pellaea pteroides (L.) Prantl, endemic
Pellaea rufa A.F.Tryon, endemic
Phanerophlebia falcata (L.f.) Copel. indigenous
Phlebodium aureum (L.) J.Sm.
Phymatosorus ensiformis (Thunb.) Pic.Serm.
Phymatosorus scandens (G.Forst.) Pic.Serm.
Phymatosorus scolopendria (Burm.f.) Pic.Serm.
Pilularia bokkeveldensis N.R.Crouch, endemic
Pilularia dracomontana N.R.Crouch & J.Wesley-Smith, endemic
Pityrogramma argentea (Willd.) Domin, indigenous
Pityrogramma calomelanos (L.) Link var. aureoflava (Hook.) Weath. ex Bailey,
Platycerium bifurcatum (Cav.) C.Chr. cultivated, invasive
Pleopeltis bampsii Pic.Serm.
Pleopeltis excavata (Bory ex Willd.) Sledge
Pleopeltis macrocarpa (Bory ex Willd.) Kaulf. indigenous
Pleopeltis polypodioides (L.) E.G.Andrews & Windham subsp. ecklonii (Kunze) J.P.Roux, indigenous
Pleopeltis schraderi (Mett.) Tardieu, indigenous
Pleopeltis x simiana (Schelpe & N.C.Anthony) N.R.Crouch & Klopper subsp. simiana, indigenous
Pneumatopteris unita (Kunze) Holttum, indigenous
Polyphlebium borbonicum (Bosch) Ebihara & Dubuisson, indigenous
Polypodium aureum L. invasive
Polypodium ensiforme Thunb. endemic
Polypodium falcatum L.f.
Polypodium polypodioides (L.) Watt subsp. ecklonii (Kunze) Schelpe, indigenous
Polypodium vulgare L. indigenous
Polystichum alticola Schelpe & N.C.Anthony, indigenous
Polystichum dracomontanum Schelpe & N.C.Anthony, near endemic
Polystichum falcatum (L.f.) Diels
Polystichum inaequale (Schltdl.) Keyserl. indigenous
Polystichum incongruum J.P.Roux, endemic
Polystichum luctuosum (Kunze) T.Moore, indigenous
Polystichum macleae (Baker) Diels, indigenous
Polystichum monticola N.C.Anthony & Schelpe, indigenous
Polystichum pungens (Kaulf.) C.Presl, indigenous
Polystichum sinense (Christ) Christ, indigenous
Polystichum transkeiense W.Jacobsen, indigenous
Polystichum transvaalense N.C.Anthony, indigenous
Polystichum wilsonii Christ, indigenous
Polystichum x saltum J.P.Roux, endemic
Pseudocyclosorus pulcher (Bory ex Willd.) Holttum, indigenous
Psilotum nudum (L.) P.Beauv. indigenous
Pteridium aquilinum (L.) Kuhn, indigenous
Pteridium aquilinum (L.) Kuhn subsp. capense (Thunb.) C.Chr. indigenous
Pteris buchananii Baker ex Sim, indigenous
Pteris catoptera Kunze, indigenous
Pteris catoptera Kunze var. horridula Schelpe, indigenous
Pteris cretica L. indigenous
Pteris dentata Forssk. indigenous
Pteris friesii Hieron. indigenous
Pteris tremula R.Br. endemic
Pteris vittata L. indigenous
Ptisana fraxinea (Sm.) Murdock, indigenous
Ptisana fraxinea (Sm.) Murdock var. salicifolia (Schrad.) Murdock, indigenous
Pyrrosia africana (Kunze) F.Ballard, indigenous
Pyrrosia schimperiana (Mett. ex Kuhn) Alston, indigenous
Pyrrosia schimperiana (Mett. ex Kuhn) Alston var. schimperiana, indigenous
Rumohra adiantiformis (G.Forst.) Ching, indigenous
Salvinia minima Baker, invasiv
Salvinia molesta D.S.Mitch. invasive
Schizaea pectinata (L.) Sw. indigenous
Schizaea tenella Kaulf. indigenous
Sphaerocionium aeruginosum (Poir.) Pic.Serm. indigenous
Sphaerocionium capillare (Desv.) Copel. indigenous
Sphaeropteris cooperi (Hook. ex F.Muell.) R.M.Tryon, cultivated, invasive
Stegnogramma pozoi (Lag.) K.Iwats. indigenous
Stenochlaena tenuifolia (Desv.) T.Moore, indigenous
Sticherus umbraculiferus (Kunze) Ching, indigenous
Tectaria gemmifera (Fee) Alston, indigenous
Thelypteris altissima (Holttum) Vorster
Thelypteris bergiana (Schltdl.) Ching
Thelypteris chaseana Schelpe
Thelypteris confluens (Thunb.) C.V.Morton, indigenous
Thelypteris dentata (Forssk.) E.P.St.John
Thelypteris gueinziana (Mett.) Schelpe
Thelypteris interrupta (Willd.) K.Iwats
Thelypteris knysnaensis N.C.Anthony & Schelpe
Thelypteris madagascariensis (Fee) Schelpe
Thelypteris oppositiformis (C.Chr.) Ching
Thelypteris pozoi (Lag.) C.V.Morton
Thelypteris pulchra (Bory ex Willd.) Schelpe
Todea barbara (L.) T.Moore, indigenous
Trichomanes borbonicum Bosch
Trichomanes dregei Bosch, indigenous
Trichomanes erosum Willd. var. aerugineum (Bosch) C.Chr. ex Bonap. indigenous
Trichomanes inopinatum (Pic.Serm.) J.E.Burrows
Trichomanes melanotrichum Schltdl.
Trichomanes reptans Sw. indigenous
Vittaria isoetifolia Bory, indigenous
Woodsia angolensis Schelpe, indigenous
Woodsia burgessiana Gerrard ex Hook. & Baker, indigenous
Woodsia montevidensis (Spreng.) Hieron. var. burgessiana (Gerrard ex Hook. & Baker) Schelpe,
See also
References
South African plant biodiversity lists
Ferns | List of pteridophytes of South Africa | [
"Biology"
] | 7,418 | [
"Ferns",
"Plants"
] |
65,462,416 | https://en.wikipedia.org/wiki/Exoplanet%20Explorers | Exoplanet Explorers was a Zooniverse citizen science project aimed at discovering new exoplanets with Kepler data from the K2 mission. The project was launched in April 2017 and reached 26,281 registered volunteers. Two campaigns took place, the first one containing 148,061 images and the second one 56,794 images.
A total of 9 exoplanets were found through the project: K2-138 b, c, d, e, f and g (initially referred to as EE-1b, EE-1c, EE-1d, and EE-1e), K2-233 b, c, and d, and K2-288Bb. K2-288Bb is considered to be potentially habitable with a radius of 1.91 Earth radii and a temperature of 206 K.
Several other candidates in size groups were also found: Jupiters: 44, Neptunes: 72, super-Earths: 53, Earths: 15.
See also
Planet Hunters
Planet Patrol
References
Astronomy | Exoplanet Explorers | [
"Astronomy"
] | 214 | [
"nan"
] |
65,462,618 | https://en.wikipedia.org/wiki/Planet%20Patrol%20%28project%29 | Planet Patrol is a NASA citizen science project available in Zooniverse and aimed at discovering new exoplanets with data from the TESS telescope.
The project is built on results produced by a computer algorithm. The algorithm measures the center-of-light of the images and automatically compares it to the catalog position of the corresponding star.
The main difference with Planet Hunters is that Planet Patrol looks at objects that represent a detected planet candidate in TESS data, whereas Planet Hunters searches through all the stars in the TESS databases and asks humans to find such candidates.
As of September 2020, there are 1370 volunteers and 72,938 classifications have been done.
The images representing a possible exoplanet transit show a single bright source near the middle of the image with a dot at the center.
Results
Two papers were published by Planet Patrol, vetting 1998 TESS Objects of Interest (TOIs). Of these TOIs 1461 passed as planet candidates, 286 were ruled out as false-positive and 251 were labelled as potential false-positive. The resulting catalog is named TESS Triple 9 (TT9), named after the number of vetted TOIs in each paper being 999.
The second TT9 paper describes interesting planet candidates, such as TIC 396720998.01 (TOI 709.01), a sub-Jovian around a hot subdwarf, named LB 1721. The planet candidate produces a V-shaped transit, which is different from the U-shaped transits that most planets produce. TOI 709.01 was previously classified as a false-positive by TRICERATOPS, another vetting tool. Because this tool uses pre-existing knowledge of its host star and transit shape, this tool might have been confused by the small size of the host star and the resulting V-shape of a transit. TOI 709.01 would be the second transiting planet around a degenerate star if confirmed. The first transiting planet around a white dwarf was WD 1856+534 b.
The paper also describes two planet candidates in the habitable zone: TOI 715.01 and the already confirmed TOI 1227 b.
See also
Planet Hunters
Exoplanet Explorers
References
astronomy | Planet Patrol (project) | [
"Astronomy"
] | 455 | [
"nan"
] |
65,463,358 | https://en.wikipedia.org/wiki/Project%20Isabela | The Project Isabela () was an environmental restoration project in the Galápagos Islands of Ecuador that took place between 1997 and 2006, initiated by the Charles Darwin Foundation and the Galápagos National Park. Species introduced in the 16th and 17th centuries to the islands, mainly goats and some donkeys and pigs, brought ecological devastation to the islands and posed as a threat to the Galápagos tortoise that was by the 1990s near extinction. By 1997, plans had been officially implemented to eradicate these introduced species in northern Isabela, Santiago, and Pinta islands. Skilled park rangers used helicopters to hunt, and sterilized Judas goats fitted with radio collars, to track down the feral goats. The initiative was brought into action in 1999, and by 2006, 150,000 goats alone were eradicated. As of 2011, the project was the world's largest ecological island restoration effort ever.
See also
List of animals in the Galápagos Islands
References
Galápagos Islands
Nature conservation in Ecuador
Pest control campaigns
Conservation projects
Ecological restoration | Project Isabela | [
"Chemistry",
"Engineering"
] | 211 | [
"Ecological restoration",
"Environmental engineering"
] |
65,465,467 | https://en.wikipedia.org/wiki/List%20of%20accredited%20HIM%20programs%20in%20the%20United%20States%20and%20Canada | In the United States, there are 352 accredited health information management (HIM) and health informatics (HI) programs. Most of these programs are in the associate degree level. In Canada, there are 19 different HIM programs, mostly in the diploma level. However, all these programs are subjected to an accreditation review by their respective organizations: The Commission on Accreditation for Health Informatics and Information Management Education (CAHIIM in the US) and the Canadian College of Health Information Management (CCHIM in Canada).
United States
The CAHIIM has given full accreditation to the following list of HIM and HI programs. However, the master's degree level programs listed makes little or no difference, in terms of whether it is a HIM, a HI, or even both together.
Associate degree
There are currently 255 American universities and colleges in this list.
Alabama
Bishop State Community College in Mobile (Campus based and online)
Wallace State Community College in Hanceville (Campus based and online)
Alaska
University of Alaska Southeast in Sitka (online only)
Arizona
Bryan University in Tempe (online only)
Central Arizona College in Coolidge (online only)
Phoenix College in Phoenix (Campus based and online)
Arkansas
Arkansas Tech University–Ozark Campus in Ozark (Campus based only)
National Park College in Hot Springs (Campus based and online)
Northwest Arkansas Community College in Bentonville (Campus based and online)
California
City College of San Francisco in San Francisco (Campus based and online)
Cosumnes River College in Sacramento (online only)
Cypress College in Cypress (Campus based and online)
East Los Angeles College in Monterey Park (Campus based only)
Saddleback College in Mission Viejo (online only)
San Diego Mesa College in San Diego (Campus based and online)
Santa Barbara City College in Santa Barbara (online only)
Shasta College in Redding (online only)
Colorado
Arapahoe Community College in Littleton (online only)
Front Range Community College in Westminster (Campus based and online)
Connecticut
Middlesex Community College in Middletown (Campus based only)
Delaware
Delaware Technical Community College in Wilmington (Campus based only)
Florida
Broward College in Fort Lauderdale (Campus based only)
College of Business and Technology in Miami (Cutler Bay location) (Campus based only)
College of Central Florida in Ocala (Campus based and online)
Daytona State College in Daytona Beach (Campus based only)
Florida Gateway College in Lake City (Campus based and online)
Florida SouthWestern State College in Fort Myers (Campus based and online)
Florida State College at Jacksonville in Jacksonville (Campus based and online)
Indian River State College in Fort Pierce (online only)
Miami Dade College in Miami (Campus based only)
Palm Beach State College in Lake Worth Beach (Campus based and online)
Pensacola State College in Pensacola (Campus based and online)
Santa Fe College in Gainesville (online only)
Seminole State College of Florida in Sanford (online only)
St. Johns River State College in St. Augustine (online only)
St. Petersburg College in St. Petersburg (online only)
Ultimate Medical Academy in Tampa (online only)
Valencia College in Orlando (online only)
Georgia
Albany State University in Albany (online only)
Athens Technical College in Athens (Campus based only) (Web site is currently offline)
Atlanta Technical College in Atlanta (Campus based only)
Augusta Technical College in Augusta (Campus based only)
Georgia Northwestern Technical College in Walker County (online only)
Gwinnett Technical College in Lawrenceville (Campus based only)
Lanier Technical College in Gainesville (Campus based and online)
Ogeechee Technical College in Statesboro (online only)
West Georgia Technical College in Waco (Campus based only)
Wiregrass Georgia Technical College in Valdosta (Campus based and online)
Hawaii
Leeward Community College in Pearl City (Campus based only)
Idaho
Idaho State University in Pocatello (online only)
Illinois
College of DuPage in Glen Ellyn (Campus based only)
College of Lake County in Grayslake (Campus based only)
Danville Area Community College in Danville (Campus based only)
DeVry University in Naperville (online only)
Harper College in Palatine (Campus based and online)
Joliet Junior College in Joliet (Campus based and online)
McHenry County College in Crystal Lake (Campus based and online)
Moraine Valley Community College in Palos Hills (Campus based only)
Northwestern College in Bridgeview (Campus based and online)
Oakton Community College in Des Plaines (Campus based only)
Richland Community College in Decatur (online only)
Southwestern Illinois College in Belleville (Campus based and online)
Indiana
Indiana Institute of Technology in Fort Wayne (online only)
Indiana University Northwest in Gary (Campus based and online)
Ivy Tech Community College of Indiana in Indianapolis and Fort Wayne (Campus based and online respectively)
Vincennes University in Vincennes (Campus based and online)
Iowa
Indian Hills Community College in Ottumwa (online only)
Northeast Iowa Community College in Calmar (Campus based and online)
Scott Community College in Riverdale (online only)
Kansas
Hutchinson Community College in Hutchinson (online only)
Neosho County Community College in Chanute (online only)
Washburn University in Topeka (online only)
Kentucky
American National University in Louisville (Campus based only)
Gateway Community and Technical College in Covington (Campus based and online)
Hazard Community and Technical College in Hazard (online only)
Jefferson Community and Technical College in Louisville (online only)
Sullivan University in (online only) at the following locations:
Louisa and Mayfield
Louisiana
Delgado Community College in New Orleans (Campus based and online)
Southern University at Shreveport in Shreveport (Campus based and online)
Maine
Beal College in Bangor (Campus based only)
Kennebec Valley Community College in Fairfield (Campus based and online)
Maryland
Baltimore City Community College in Baltimore (Campus based only)
Community College of Baltimore County in Baltimore County (Campus based and online)
Montgomery College in Montgomery County (Campus based and online)
Prince George's Community College in Largo (Campus based and online)
Massachusetts
Fisher College in Boston (online only)
Springfield Technical Community College in Springfield (Campus based only)
Michigan
Davenport University in Grand Rapids (online only)
Ferris State University in Big Rapids (Campus based only)
Macomb Community College in Warren (Campus based and online)
Schoolcraft College in Livonia (Campus based only)
Southwestern Michigan College in Dowagiac (Campus based only)
Minnesota
Anoka Technical College in Anoka (online only)
Minnesota State Community and Technical College in (all online only) at the following locations:
Moorhead, Fergus Falls, Detroit Lakes, and Wadena
Minnesota West Community and Technical College in (all online only) at the following locations:
Canby, Granite Falls, Jackson, Pipestone, and Worthington
Rasmussen College in (Campus based and online) at the following locations:
Bloomington, Brooklyn Park, Aurora and Rockford, and Green Bay
Ridgewater College in Willmar (online only)
Rochester Community and Technical College in Rochester (online only)
Saint Paul College in Saint Paul (Campus based and online)
St. Cloud Technical and Community College in St. Cloud (Campus based and online)
Mississippi
Hinds Community College in Raymond (Campus based and online)
Itawamba Community College in Tupelo (Campus based and online)
Meridian Community College in Meridian (Campus based and online)
Southwest Mississippi Community College in Summit (Campus based and online)
Missouri
East Central College in Union (online only)
Jefferson College in Hillsboro (Campus based and online)
Metropolitan Community College in Kansas City (Campus based and online)
Ozarks Technical Community College in Springfield (online only)
St. Charles Community College in St. Charles (online only)
St. Louis Community College at Forest Park in St. Louis (Campus based and online)
State Fair Community College in Sedalia (online only)
Montana
Great Falls College Montana State University in Great Falls (online only)
Nebraska
Central Community College in Grand Island (online only)
Clarkson College in Omaha (online only)
Metropolitan Community College in Omaha (online only)
Northeast Community College in Norfolk (Campus based and online)
Western Nebraska Community College in Scottsbluff (online only)
Nevada
College of Southern Nevada in Clark County (Campus based and online)
New Jersey
Camden County College in Blackwood (online only)
Passaic County Community College in Paterson (Campus based and online)
Raritan Valley Community College in Branchburg (online only)
Rowan College at Burlington County in Mount Laurel (Campus based and online)
New Mexico
Central New Mexico Community College in Albuquerque (online only)
San Juan College in Farmington (online only)
The University of New Mexico in Gallup (Campus based and online)
New York
Alfred State College in Alfred (online only)
Borough of Manhattan Community College in New York City (Campus based only)
SUNY Erie in Williamsville (Campus based and online)
Mohawk Valley Community College in Utica (online only)
Nassau Community College in Garden City (Campus based only)
Onondaga Community College in Syracuse (Campus based and online)
Plaza College in Forest Hills, Queens (New York City) (Campus based only)
Suffolk County Community College in Selden (Campus based and online)
SUNY Broome Community College in Binghamton (Campus based and online)
North Carolina
Brunswick Community College in Bolivia (Campus based only)
Catawba Valley Community College in Hickory (Campus based only)
Central Carolina Community College in Harnett County (online only)
Central Piedmont Community College in Charlotte (online only)
Craven Community College in New Bern (Campus based and online)
Davidson County Community College in Davidson County (Campus based and online)
Durham Technical Community College in Durham (Campus based and online)
Edgecombe Community College in Tarboro (online only)
McDowell Technical Community College in Marion (Campus based and online)
Pitt Community College in Winterville (online only)
Southwestern Community College in Sylva (Campus based and online)
North Dakota
North Dakota State College of Science in Wahpeton (online only)
Ohio
Cincinnati State Technical and Community College in Cincinnati (online only)
Columbus State Community College in Columbus (online only)
Cuyahoga Community College in Cuyahoga County (Campus based only)
Eastern Gateway Community College in Steubenville (Campus based and online)
Lakeland Community College in Kirtland (Campus based only)
Marion Technical College in Marion (online only)
Mercy College of Ohio in Toledo (online only)
Owens Community College in Toledo (Campus based and online)
Sinclair Community College in Dayton (Campus based and online)
Stark State College in North Canton (Campus based and online)
Terra State Community College in Fremont (Campus based and online)
University of Cincinnati in Cincinnati (online only)
University of Northwestern Ohio in Lima (Campus based and online)
Zane State College in Zanesville (online only)
Oklahoma
Rose State College in Midwest City (Campus based only)
Tulsa Community College in Tulsa (Campus based and online)
Oregon
Central Oregon Community College in Bend (Campus based only)
Chemeketa Community College in Salem (online only)
Lane Community College in Eugene (online only)
Portland Community College in Portland (online only)
Pennsylvania
Community College of Allegheny County in Allegheny County (Campus based only)
Lehigh Carbon Community College in Schnecksville (Campus based and online)
Peirce College in Philadelphia (Campus based and online)
South Hills School of Business & Technology in (Campus based only) at the following locations:
State College & Altoona
Puerto Rico
Huertas College in Caguas (Campus based only and in Spanish)
South Carolina
Florence–Darlington Technical College in Florence (Campus based only)
Greenville Technical College in Greenville (Campus based and online)
Trident Technical College in Charleston (Campus based only)
South Dakota
Dakota State University in Madison (Campus based and online)
National American University in Rapid City (online only)
Tennessee
Concorde Career College in Memphis (Campus based only)
Dyersburg State Community College in Dyersburg (online only)
Roane State Community College in Harriman (online only)
Volunteer State Community College in Gallatin (Campus based and online)
Walters State Community College in Morristown (online only)
Texas
Austin Community College District in Austin (Campus based only)
Blinn College in Brenham (online only)
College of the Mainland in Texas City (Campus based and online)
Collin College in Collin County (online only)
Del Mar College in Corpus Christi (Campus based and online)
El Paso Community College in El Paso (Campus based and online)
Houston Community College in Houston (Campus based and online)
Lamar Institute of Technology in Beaumont (online only)
Lee College in Baytown (Campus based and online)
Lone Star College–North Harris in Harris County (online only)
McLennan Community College in Waco (online only)
Midland College in Midland (online only)
Panola College in Carthage (Campus based and online)
San Jacinto College in Houston (Campus based and online)
South Texas College in McAllen (Campus based and online)
St. Philip's College in San Antonio (online only)
Tarrant County College in Fort Worth (Campus based only)
Texas State Technical College in Abilene (online only)
Tyler Junior College in Tyler (online only)
Vernon College in Vernon (Campus based and online)
Wharton County Junior College in Wharton (online only)
Utah
Weber State University in Ogden (Campus based and online)
Virginia
ECPI University in Newport News and Richmond (online only)
Lord Fairfax Community College in Middletown (online only)
Mountain Empire Community College in Big Stone Gap (Campus based and online)
Northern Virginia Community College in Springfield (Campus based and online)
Tidewater Community College in Virginia Beach (Campus based only)
Washington
Shoreline Community College in Shoreline (online only)
Spokane Community College in Spokane (Campus based and online)
Tacoma Community College in Tacoma (online only)
West Virginia
Blue Ridge Community and Technical College in Martinsburg (Campus based and online)
Mountwest Community and Technical College in Huntington (Campus based and online)
Pierpont Community and Technical College in Fairmont (Campus based only)
West Virginia Northern Community College in Wheeling (Campus based and online)
Wisconsin
Chippewa Valley Technical College in Eau Claire (Campus based and online)
Fox Valley Technical College in Grand Chute (Campus based and online)
Gateway Technical College in Kenosha (online only)
Herzing University in Milwaukee (online only)
Lakeshore Technical College in Cleveland (Campus based and online)
Mid-State Technical College in Marshfield (online only)
Moraine Park Technical College in Fond du Lac (online only)
Northeast Wisconsin Technical College in Green Bay (online only)
Southwest Wisconsin Technical College in Fennimore (online only)
Waukesha County Technical College in Pewaukee (Campus based and online)
Western Technical College in La Crosse (Campus based and online)
Wisconsin Indianhead Technical College in Shell Lake (online only)
Bachelor's degree
There are currently 73 American universities and colleges in this list.
A
Alabama State University in Montgomery (Campus based only)
American Public University System in Charles Town (online only)
Arkansas Tech University in Russellville (Campus based only)
Ashford University in San Diego (online only)
Augusta University in Augusta (Campus based and online)
C
Charter Oak State College in New Britain (online only)
Chicago State University in Chicago (Campus based only)
Clarkson College in Omaha (online only)
Coppin State University in Baltimore (Campus based and online)
CUNY School of Professional Studies in New York City (online only)
D
Dakota State University in Madison (Campus based and online)
Davenport University in Grand Rapids (online only)
DeVry University in Naperville (online only)
E
East Carolina University in Greenville (Campus based only)
Eastern Kentucky University in Richmond (Campus based only)
F
Ferris State University in Big Rapids (Campus based and online)
Fisher College in Boston (online only)
Florida A&M University in Tallahassee (Campus based only)
Franklin University in Columbus (online only)
G
Grand Valley State University in Allendale (Campus based only)
H
Herzing University in Milwaukee (online only)
I
Illinois State University in Normal (Campus based and online)
Indiana University in Indianapolis (Campus based and online)
Indiana University Northwest in Gary (Campus based and online)
K
Keiser University in Fort Lauderdale (online only)
L
Loma Linda University in Loma Linda (Campus based and online)
Long Island University (LIU Post) in Brookville (Campus based and online)
Louisiana Tech University in Ruston (Campus based and online)
M
Missouri Western State University in St. Joseph (online only)
P
Parker University in Dallas (online only)
Peirce College in Philadelphia (Campus based and online)
R
Rasmussen College in Bloomington (online only)
Rutgers University in New Brunswick (online only)
S
Saint Joseph's College of Maine in Standish (online only)
Saint Louis University in St. Louis (Campus based only)
San Diego Mesa College in San Diego (Campus based and online)
Shasta College in Redding (online only)
Southern New Hampshire University in Manchester (online only)
Southern University at New Orleans in New Orleans (Campus based and online)
Southwestern Oklahoma State University in Weatherford (online only)
Stephens College in Columbia (online only)
SUNY Polytechnic Institute in Albany (online only)
T
Tacoma Community College in Tacoma (online only)
Temple University in Philadelphia (Campus based only)
Tennessee State University in Nashville (Campus based and online)
Texas Southern University in Houston (Campus based only)
Texas State University in San Marcos (Campus based and online)
The College of St. Scholastica in Duluth (Campus based and online)
The Ohio State University in Columbus (Campus based only)
U
University of Central Florida in Orange County (Campus based and online)
University of Cincinnati in Cincinnati (online only)
University of Detroit Mercy in Detroit (Campus based and online)
University of Illinois at Chicago in Chicago (Campus based and online)
University of Kansas Medical Center in Kansas City (Campus based and online)
University of Louisiana at Lafayette in Lafayette (Campus based only)
University of Mississippi Medical Center in Jackson (online only)
University of Pittsburgh in Pittsburgh (Campus based only)
University of Puerto Rico, Medical Sciences Campus in San Juan (Campus based only) (Web site is currently offline)
University of Saint Mary in Leavenworth (Campus based only)
University of South Carolina Upstate in Spartanburg (online only)
University of Toledo in Toledo (online only)
University of Washington in Seattle (Campus based only)
University of Wisconsin in (all online only):
University of Wisconsin–Green Bay in Green Bay
University of Wisconsin–Parkside in Somers
University of Wisconsin–Stevens Point in Stevens Point
W
Weber State University in Ogden (Campus based and online)
Western Governors University in Salt Lake City (online only)
Western Kentucky University in Bowling Green (online only)
William Carey University in Hattiesburg (Campus based only)
Master's degree in health information management
Dakota State University in Madison (online only)
Davenport University in Grand Rapids (online only)
Texas State University in San Marcos (online only)
The College of St. Scholastica in Duluth (online only)
University of Tennessee Health Science Center in Memphis (online only)
Master's degree in health informatics
Boston University in Boston (Campus based and online)
Drexel University in Philadelphia (online only)
East Carolina University in Greenville (Campus based and online)
Florida International University in University Park (online only)
George Mason University in Fairfax County (Campus based and online)
Indiana University in Indianapolis (Campus based and online)
Louisiana Tech University in Ruston (online only)
Marshall University in Huntington (Campus based only)
Medical University of South Carolina in Charleston (Campus based and online)
Oregon Health & Science University in Portland (online only)
Southern Illinois University Edwardsville in Edwardsville (online only)
Temple University in Philadelphia (Campus based and online)
The College of St. Scholastica in Duluth (online only)
University of Alabama at Birmingham in Birmingham (online only)
University of Central Florida in Orange County (online only)
University of Illinois at Chicago in Chicago (online only)
University of Maryland Global Campus in Adelphi (online only)
University of Mississippi Medical Center in Jackson (online only)
University of Pittsburgh in Pittsburgh (Campus based only)
University of South Carolina in Columbia (Campus based and online)
University of Texas Health Science Center at Houston in Houston (Campus based and online)
University of Washington in Seattle (Campus based only)
Canada
In Canada, the Canadian College of Health Information Management (CCHIM) has listed the following accredited Canadian institutions.
Certificate
: Bow Valley College in Calgary
: CanScribe Career College in Kelowna
: Manitoba Institute of Trades and Technology in Winnipeg
: 3M Clinical Documentation Improvement Specialist Program
: Fanshawe College in London
: HealthCareCAN/CHA Learning Health Information Coding Specialist in Ottawa
: HealthCareCAN/CHA Learning Health Information Management (in conjunction with Algonquin College) in Ottawa
Certificate or Diploma
: McMaster University in Hamilton
Diploma
: Southern Alberta Institute of Technology in Calgary
: Ashton College in Vancouver
: Western Community College in Abbotsford or Surrey
: Red River College Polytechnic in Winnipeg
: College of the North Atlantic in Stephenville
: Centre for Distance Education (CD-ED) in Sydney
: Nova Scotia Community College in Halifax
: Algonquin College in Ottawa
: Anderson College in London
: Fleming College in Peterborough
: George Brown College in Toronto
: Georgian College in Barrie
: St. Clair College in Windsor
: St. Lawrence College in Kingston
: Sheridan College in Mississauga
: TriOS College
: Collège Laflèche in Trois-Rivières (in French)
: Saskatchewan Polytechnic in Regina
Postbaccalaureate diploma
: Douglas College in Coquitlam
Postgraduate certificate
: University of Victoria in Victoria
: Mohawk College in Hamilton
Bachelor's degree
: Conestoga College in Kitchener
: Toronto Metropolitan University in Toronto
Master's degree
: Johnson Shoyama Graduate School of Public Policy (with the University of Regina) in Regina
References
Healthcare in the United States
Healthcare in Canada
Health informatics | List of accredited HIM programs in the United States and Canada | [
"Biology"
] | 4,422 | [
"Health informatics",
"Medical technology"
] |
65,465,813 | https://en.wikipedia.org/wiki/YGL%20motif | The YGL motif (or the amino acids in sequence of Tyrosine-Glycine-Leucine) is an integrin-binding motif present in several viral glycoproteins including Equine Herpes Virus (EHV) 1, EHV-4, and in rotavirus VP4.
References
Protein structural motifs | YGL motif | [
"Biology"
] | 74 | [
"Protein structural motifs",
"Protein classification"
] |
65,466,889 | https://en.wikipedia.org/wiki/Crude%20oil%20stabilisation | Crude oil stabilisation (or stabilization) is a partial distillation process that renders crude oil suitable for storage in atmospheric tanks, or of a quality suitable for sales or pipeline transportation. Stabilization is achieved by subjecting ‘live’ crude to temperature and pressure conditions in a fractionation vessel, which drives off light hydrocarbon components to form a ‘dead’ or stabilized crude oil with a lower vapor pressure.
Specification
Typically, the live crude from an oil production installation would have a vapor pressure of 120 psia at 100 °F (726 kPa at 37.8 °C) or 125 psig at 60 °F (862 kPa at 15.5 °C). After stabilisation dead crude would have a Reid vapor pressure of 9 – 10 psig at 100 °F (62 – 69 kPa at 37.8 °C).
The stabilization process
Live crude is heated in a furnace or heat exchanger to an elevated temperature. The crude oil is fed to a stabilizer which is typically a tray or packed tower column that achieves a partial fractionation or distillation of the oil. The heavier components, pentane (C5H12), hexane (C6H14), and higher hydrocarbons (C7+), flow as liquid down through the column where the temperature is increasingly higher. At the bottom of the column, some of the liquid is withdrawn and circulated through a reboiler which adds heat to the tower. Here the lighter fractions are finally driven off as a gas, which rises up through the column. At each tray or stage, the rising gas strips the light ends from heavy ends, and the rising gas becomes richer in the light components and leaner in the heavy ends.
Alternatively, if a finer separation is required the column may be provided with an upper section reflux system making it similar to a distillation column. As the reflux liquid flows down through the column it becomes leaner in light components and richer in heavy ends. Overhead gas from the stabilizer passes through a back pressure control valve that maintains the pressure in the stabilizer.
The stabilised crude oil, comprising pentane and higher hydrocarbons (C5+), is drawn from the base of the stabilizer and is cooled. This may be by heat exchange with the incoming live crude and by cooling water in a heat exchanger. The dead, stabilized crude flows to tanks for storage or to a pipeline for transport to customers such as an oil refinery.
The stabilization tower may typically operate at approximately 50 to 200 psig (345 – 1378 kPa). Where the crude oil contains high levels of hydrogen sulphide (H2S) a sour stabilization is undertaken. This entails operating the stabilizer at the lower end of the pressure range, whereas sweet (low H2S) stabilization would take place at a higher pressure.
Gas processing
The light hydrocarbons stripped from the crude are usually processed to yield useful products. Gas from the top of the stabilizer column is compressed and fed to a de-methanizer column. This column separates the lightest hydrocarbons, methane (CH4) and ethane (C2H6), from the heavier components. Methane and ethane are withdrawn from the top of the column and are used as fuel gas in the plant. Excess gas may be flared.
Liquid from the base of the de-methanizer is routed to the de-ethanizer. Gas from the top is principally ethane and is compressed and returned to the de-methanizer.
Liquid from the base of the de-ethanizer is routed to the de-propanizer. Gas from the top is principally propane (C3H8) and is compressed or chilled for storage and sales.
Liquid from the base of the de-propanizer is principally butane (C4H10) and some heavier components. Butane is stored and sold, and the heavier fraction is sold or spiked into the stabilized crude.
See also
Oil production plant
Oil platform
Upstream (oil industry)
Oil industry
Flotta oil terminal
Sullom Voe terminal
References
Petroleum technology
Oil refining
Distillation | Crude oil stabilisation | [
"Chemistry",
"Engineering"
] | 849 | [
"Separation processes",
"Petroleum engineering",
"Petroleum technology",
"Distillation",
"Oil refining"
] |
65,467,021 | https://en.wikipedia.org/wiki/Lion%20algorithm | Lion algorithm (LA) is one among the bio-inspired (or) nature-inspired optimization algorithms (or) that are mainly based on meta-heuristic principles. It was first introduced by B. R. Rajakumar in 2012 in the name, Lion’s Algorithm.. It was further extended in 2014 to solve the system identification problem. This version was referred as LA, which has been applied by many researchers for their optimization problems.
Inspiration from lion’s social behaviour
Lions form a social system called a "pride", which consists of 1–3 pair of lions. A pride of lions shares a common area known as territory in which a dominant lion is called as territorial lion. The territorial lion safeguards its territory from outside attackers, especially nomadic lions. This process is called territorial defense. It protects the cubs till they become sexually matured. The maturity period is about 2–4 years. The pride undergoes survival fights to protect its territory and the cubs from nomadic lions. Upon getting defeated by the nomadic lions, the dominating nomadic lion takes the role of territorial lion by killing or driving out the cubs of the pride. The lioness of the pride give birth to cubs though the new territorial lion. When the cubs of the pride mature and considered to be stronger than the territorial lion, they take over the pride. This process is called territorial take-over. If territorial take-over happens, either the old territorial lion, which is considered to be laggard, is driven out or it leaves the pride. The stronger lions and lioness form the new pride and give birth to their own cubs
Terminology
In the LA, the terms that are associated with lion’s social system are mapped to the terminology of optimization problems. Few of such notable terms are related here.
Lion: A potential solution to be generated or determined as optimal (or) near-optimal solution of the problem. The lion can be a territorial lion and lioness, cubs and nomadic lions that represent the solution based on the processing steps of the LA.
Territorial lion: The strongest solution of the pride that tends to meet the objective function.
Nomadic lion: A random solution, sometimes termed as nomad, to facilitate the exploration principle
Laggard lion: Poor solutions that are failed in the survival fight.
Pride: A pool of potential solutions i.e. a lion, lioness and their cubs, that are potential solutions of the search problem.
Fertility evaluation: A process of evaluating whether the territorial lion and lioness are able to provide potential solutions in the future generations i.e. It ensures that the lion or lioness converge at every generation.
Survival fight: It is a greedy selection process, which is often carried out between the pride and nomadic lion.
Algorithm
The steps involved in LA are given below:
Pride Generation: Generate , and
Determine , ,
Initialize as and as 0
Memorize and
Apply Fertility evaluation Process
Generation of cubpool by mating
Gender clustering: Define and
Initialize as zero
Apply Cub growth function
Territorial defense: If (or pride) fails in the survival fight i.e. defeats the pride, go to step 4, else continue
Increase by 1 and check whether cub attains maturity i.e., if , go to Step 9, else continue
Territorial takeover: If and are found to be closer to optimal solution, update and
Increment by 1
Repeat from Step 5, if termination criterion is not violated, else return as the near-optimal solution
Variants
The LA has been further taken forward to adopt in different problem areas. According to the characteristics of the problem area, significant amendment has been done in the processes and the models used in the LA. Accordingly, diverse variants have been developed by the researchers. They can be broadly grouped as hybrid LAs and non-hybrid LAs. Hybrid LAs are the LAs that are amended by the principle of other meta-heuristics, whereas the Non-hybrid LAs take any scientific amendment inside its operation that are felt to be essential to attend the respective problem area.
Applications
LA is applied in diverse engineering applications that range from network security, text mining, image processing, electrical systems, data mining and many more. Few of the notable applications are discussed here.
Networking applications: In WSN, LA is used to solve the cluster head selection problem by determining optimal cluster head. Route discovery problem in both the VANET and MANET are also addressed by the LA in the literature. It is also used to detect attacks in advanced networking scenarios such as Software-Defined Networks (SDN)
Power Systems: LA has attended generation rescheduling problem in a deregulated environment, optimal localization and sizing of FACTS devices for power quality enhancement and load-frequency controlling problem
Cloud computing: LA is used in optimal container-resource allocation problem in cloud environment and cloud security
References
Algorithms | Lion algorithm | [
"Mathematics"
] | 972 | [
"Algorithms",
"Mathematical logic",
"Applied mathematics"
] |
65,467,710 | https://en.wikipedia.org/wiki/HC-067047 | HC-067047 is a drug which acts as a potent and selective antagonist for the TRPV4 receptor. It has been used to investigate the role of TRPV4 receptors in a number of areas, such as regulation of blood pressure, bladder function and some forms of pain, as well as neurological functions.
See also
JWH-147
RN-9893
SET2
ZINC17988990
References
Pyrroles | HC-067047 | [
"Chemistry"
] | 93 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
65,468,359 | https://en.wikipedia.org/wiki/PmPV1 | Pomacea maculata perivitellin-1 (PmPV1) is the most abundant perivitellin found in the perivitelline fluid from Pomacea maculata snail eggs. This glyco-lipo-caroteno protein is an approx. 294 kDa multimer of a combination of multiple copies of six different~30 kDa subunits. PmPV1 account >60% of the total proteins found in the Pomacea maculata eggs.
PmPV1 is an orthologous of ovorubin and scalarin, sharing most of the structural features with the former protein and cross-reacting with anti-ovorubin polyclonal antibodies. Like ovorubin and scalarin, PmPV1 is highly glycosylated (~13% w/w) and carries carotenoid pigments, indicating that this perivitellin would probably have the antioxidant, photoprotective, aposematic and water retention functions described for its orthologous.
PmPV1 is a kinetically stable protein that, like most other studied perivitellins from Pomacea snails, is highly stable in a wide range of pH values and withstands gastrointestinal digestion, characteristics associated with an antinutritive defense system that deters predation by lowering the nutritional value of the eggs. Remarkably, and in agreement with this antinutritive activity, PmPV1 withstands in vivo digestion, being recovered structurally unaltered from mice feces after trespassing the whole digestive system.
References
Proteins | PmPV1 | [
"Chemistry"
] | 340 | [
"Biomolecules by chemical classification",
"Protein stubs",
"Biochemistry stubs",
"Molecular biology",
"Proteins"
] |
65,468,475 | https://en.wikipedia.org/wiki/Scalarin | Scalarin (PsSC) is the most abundant perivitellin of the perivitelline fluid from Pomacea scalaris eggs. This glyco-lipo-caroteno protein is an approx. 380 kDa multimer combining multiple copies of six different 24-35 kDa subunits.
As part of the petivitelline fluid, PsSC is probably playing a role as a nutrient source for the developing embryo in Pomacea scalaris eggs. As its orthologous ovorubin and PmPV1, this protein carries and stabilizes carotenoid pigments. As a consequence, this perivitellin absorbs light throughout the visible range, a characteristic related to a photoprotective role in these aerially deposited eggs. The presence on its structure of carotenoid pigments is also associated with protective antioxidative properties.
Like most other studied perivitellins from Pomacea snails, PsSC is highly stable in a wide range of pH values and withstands gastrointestinal digestion, characteristics associated with an antinutritive defense system that deters predation by lowering the nutritional value of the eggs.
Unlike ovorubin and PmPV1, PsSC is an active, strong lectin, recognizing glycosphingolipids (notably, the gangliosides GD1b, GT1b, and GD1a) and AB0 group antigens. Due to this activity, PsSC agglutinates red blood cells (notably those from rabbits and human A and B groups) as well as Gram-negative bacteria, indicating a putative immune role of this perivitellin. PsSC also binds to intestinal cells in culture and, when ingested, alters the morphophysiology of rat intestinal mucosa increasing its absorptive surface by elongating and narrowing villi, further supporting its role in a defense system against predation.
References
Proteins | Scalarin | [
"Chemistry"
] | 417 | [
"Biomolecules by chemical classification",
"Protein stubs",
"Biochemistry stubs",
"Molecular biology",
"Proteins"
] |
65,468,597 | https://en.wikipedia.org/wiki/Perivitellin-2 | Perivitellin-2 (PV2) is a pore-forming toxin present in the egg perivitelline fluid of the apple snails Pomacea maculata (PmPV2) and Pomacea canaliculata (PcPV2). This protein, called perivitellin, is massively accumulated in the eggs (~20 % total protein). As a toxin PV2 protects eggs from predators, but it also nourishes the developing snail embryos.
Structure and stability
These ~172-kDa proteins are dimers of AB toxins, each composed of a carbohydrate-binding protein of the tachylectin family (targeting module) disulfide-linked to a pore-forming protein of the Membrane Attack Complex and Perforin (MACPF) family (toxic unit). Like most other studied perivitellins from Pomacea snails, PV2s are highly stable in a wide range of pH values and withstand gastrointestinal digestion, characteristics associated with an antinutritive defense system that deters predation by lowering the nutritional value of the eggs.
Functions
As part of the perivitelline fluid, perivitellin-2 constitutes a nutrient source for the developing embryo, notably in the last stages where it is probably used as an endogenous source of energy and structural molecules during the transition to the free life. PV2s also play a role in a complex defense system that protects the embryos against predation.
PV2s have both lectin and perforin activities, associated to the two subunits of their particular structures. As a lectin, PV2s can agglutinate rabbit red blood cells and bind to the plasma membrane of intestinal cells both in vitro and in vivo. As a perforin, PV2s are able to disrupt intestinal cells altering the plasma membrane conductance and to form large pores in artificial lipid bilayers. An interesting issue with these perivitellins is that the combination of two immune proteins (lectin and perforin) gave rise to a new toxic entity, an excellent example of protein exaptation. This binary structure includes PV2s within “AB-toxins”, a group of toxins mostly described in bacteria and plants. In PV2 toxins, the lectin would bind to target membranes through the recognition of specific glycans, acting as a delivery “B” subunit, and then the pore-forming “A” subunit would disrupt lipid bilayers forming large pores and leading to cell death, therefore constituting a true pore-forming toxin.
Toxicity toward mammals
PV2 toxins proved to be highly toxic to mice when it enters the bloodstream (LD50, 96 h 0.25 mg/kg, i.p.) and those receiving sublethal doses displayed neurological signs including weakness and lethargy, low head and bent down position (ortopneic), half-closed eyes, taquipnea, hirsute hair, extreme abduction of the rear limbs, paresia and were not able to support their body weight (tetraplegic), among others. Histopathological analyses of affected mice showed that PV2 toxins affect the dorsal horn of the spinal cord, particularly on the 2nd and 3rd gray matter laminas, where alters the calcium metabolism and causes neuron apoptosis. Apart from its neurotoxicity, it has been recently shown that PV2s are also enterotoxic to mice when ingested, a function that had never been ascribed to animal proteins. At the cellular level, PV2 is cytotoxic to intestinal cells, on which it causes changes in their surface morphology increasing the membrane roughness. At the system level, oral administration of PV2 induces large morphological changes on mice intestine mucosa, reducing its absorptive surface. Additionally, PV2 reaches the Peyer's patches where it activates lymphoid follicles and triggers apoptosis.
Evolution of a pore-forming toxin
Proteomic analysis indicates that the MACPF and the Tachylectins are among the most abundant proteins in Pomacea eggs but are minor proteins in the genera laying eggs below the water. According to the fossil record, some 3 MYA, when Pomacea diverged from Marisa and began laying eggs above the water, these two genes were subjected to extensive duplication and these unrelated proteins were combined by a covalent bond resulting in the dimerization into PV2 AB toxin that co-opted to new roles. This new structure rendered a novel toxin that is non-digestible, enterotoxic and neurotoxic.
References
Proteins
Storage proteins
Neurotoxins
Toxins | Perivitellin-2 | [
"Chemistry",
"Environmental_science"
] | 996 | [
"Biomolecules by chemical classification",
"Toxicology",
"Molecular biology",
"Toxins",
"Proteins",
"Neurochemistry",
"Neurotoxins"
] |
65,469,204 | https://en.wikipedia.org/wiki/Harry%20Hurwitz%20%28psychologist%29 | Harry M.B. Hurwitz (died 2018) was a Canadian psychologist who specialised in the field of behavior analysis.
Life
Harry Hurwitz was born in Berlin, Germany to a Jewish family. With the rise of fascism in the 1930s, the family fled to South Africa where he obtained his first degree in philosophy and psychology. He then moved to England where he obtained a PhD from the Birkbeck, University of London in 1953 for a thesis entitled Studies in operant chaining.
He was a lecturer at Birkbeck College for twelve years (1953-1965) where he established an operant psychology laboratory. He invited many behaviourist psychologists, including B.F. Skinner, to the laboratory and it became a centre for discussion on behaviourism. It was here that Hurwitz established the British Experimental Analysis of Behaviour Group. Peter Harzem was influenced by these discussions and conducted some early research in this laboratory before going on to further develop these ideas.
Hurwitz then moved to North America, first to the University of Tennessee (1964-1971) and then to the University of Guelph, Canada (1971-1983) where he became Chair of Psychology. He remained there until he retired as Emeritus Professor in 1983.
He died in Toronto in 2018.
Work
Harzem established a reputation for his work on behaviour analysis. He also had a continuing interest in the philosophy of science.
Positions
Editorial Board, Psychologische Forschung/Psychological Research
President, Ontario Council of Academic Psychologists
Publications
Hurwitz, H. M. B. & Davis, H. (1983). The description and analysis of conditioned suppression: A critique of the conventional suppression ratio. Animal Learning & Behavior, 11, 383–390.
Davis, H., & Hurwitz, H. (eds)(1977). Operant-Pavlovian Interactions. Hillsdale, N.J.: Lawrence Erlbaum Associates.
Roberts, A.E., Greenway, L., & Hurwitz, H.M.B. (1970). Extinction of free operant avoidance behavior with and without feedback. Psychonomic Science,20,282-285.
Hurwitz, H.M.B., & Roberts, A.E. (1971). Time-out as a determinant of rate of response and rate of avoidance Psychonomic Science, 24, 131–133.
Hurwitz, H.M.B., Roberts, A.E., & Greeway, L. (1972). Extinction and maintenance of avoidance behavior using response-independent shocks. Psychonomic Science, 28(3), 176–178.
References
2018 deaths
People from Berlin
20th-century Canadian psychologists
Behaviourist psychologists | Harry Hurwitz (psychologist) | [
"Biology"
] | 565 | [
"Behaviourist psychologists",
"Behavior",
"Behaviorism"
] |
65,469,473 | https://en.wikipedia.org/wiki/Holdfast%20%28artillery%29 | A holdfast or hold fast is a means by which artillery is fixed firmly to the ground.
One type of holdfast is a concrete base or plinth that a gun is bolted to. These were used, for example, to secure coastal battery guns in pillboxes during World War II.
References
Artillery components | Holdfast (artillery) | [
"Technology"
] | 65 | [
"Artillery components",
"Components"
] |
65,470,508 | https://en.wikipedia.org/wiki/Quadratic%20Fourier%20transform | In mathematical physics and harmonic analysis, the quadratic Fourier transform is an integral transform that generalizes the fractional Fourier transform, which in turn generalizes the Fourier transform.
Roughly speaking, the Fourier transform corresponds to a change of variables from time to frequency (in the context of harmonic analysis) or from position to momentum (in the context of quantum mechanics). In phase space, this is a 90 degree rotation. The fractional Fourier transform generalizes this to any angle rotation, giving a smooth mixture of time and frequency, or of position and momentum. The quadratic Fourier transform extends this further to the group of all linear symplectic transformations in phase space (of which rotations are a subgroup).
More specifically, for every member of the metaplectic group (which is a double cover of the symplectic group) there is a corresponding quadratic Fourier transform.
References
Fourier analysis
Integral transforms
Time–frequency analysis | Quadratic Fourier transform | [
"Physics"
] | 187 | [
"Spectrum (physical sciences)",
"Time–frequency analysis",
"Frequency-domain analysis",
"Quantum mechanics",
"Quantum physics stubs"
] |
65,471,441 | https://en.wikipedia.org/wiki/Froissart%20bound | In particle physics the Froissart bound, or Froissart limit, is a generic constraint that the total scattering cross section of two colliding high-energy particles cannot increase faster than , with c a normalization constant and s the square of the center-of-mass energy (s is one of the three Mandelstam variables).
See also
S-matrix theory
Regge theory
Further reading
The Froissart bound on scholarpedia, by M. Froissart
References
Scattering theory | Froissart bound | [
"Physics",
"Chemistry"
] | 107 | [
"Particle physics stubs",
"Scattering",
"Scattering theory",
"Particle physics"
] |
65,471,496 | https://en.wikipedia.org/wiki/Ripper%20Method | The Ripper Method, developed in 1898, is an analytical chemistry technique used to determine the total amount of sulfur dioxide (SO2) in a solution. This technique uses iodine standard and a starch indicator to titrate the solution and determine the concentration of free SO2. The titration is done again with a new sample of the solution, but the sample is pretreated with sodium hydroxide (NaOH) to release bound SO2. The result of these two titrations can then be used to determine the bound, free, and total amount of SO2 in the solution. Instead of using a starch indicator, an electrode can be used to determine the presence of free iodine. This technique is widely used in wine making.
Chemical Equilibria
The first reaction of iodine with SO2 and water is as follows:
SO2+I2+2H2O→H2SO4+2HI
As the reaction proceeds, all available SO2 will be consumed and the starch indicator added to the solution will bind with the unconsumed iodine, turning the solution black.
The second step of the reaction requires pretreating with solution with NaOH to release bound SO2. The reaction with iodine can then be done.
HSO3−⇌H2SO3⇌SO2
Applications
The Ripper Method is commonly used in wine making applications as SO2 is often added to wine to maintain its freshness and the concentration needs to be determined. The technique is not precise and is prone to systematic error as well. This limits its use, despite being a fast and inexpensive test.
References
Titration | Ripper Method | [
"Chemistry"
] | 337 | [
"Instrumental analysis",
"Titration"
] |
65,472,459 | https://en.wikipedia.org/wiki/MACD%20operations | MACD operations are basic actions (Move, Add, Change, Delete) taken by computer network or telecom service agents in the support of hardware and services. It can also refer to the "hours" spent and billed doing those kinds of support tasks.
See also
Call center
Customer service
Technical support
References
Computer networks
Telecommunications | MACD operations | [
"Technology"
] | 65 | [
"Information and communications technology",
"Computing stubs",
"Telecommunications"
] |
65,472,779 | https://en.wikipedia.org/wiki/Kovner%E2%80%93Besicovitch%20measure | In plane geometry the Kovner–Besicovitch measure is a number defined for any bounded convex set describing how close to being centrally symmetric it is. It is the fraction of the area of the set that can be covered by its largest centrally symmetric subset.
Properties
This measure is one for a set that is centrally symmetric, and less than one for sets whose closure is not centrally symmetric. It is invariant under affine transformations of the plane. If is the center of symmetry of the largest centrally-symmetric set within a given convex body , then the centrally-symmetric set itself is the intersection of with its reflection across .
Minimizers
The convex sets with the smallest possible Kovner–Besicovitch measure are the triangles, for which the measure is 2/3. The result that triangles are the minimizers of this measure is known as Kovner's theorem or the Kovner–Besicovitch theorem, and the inequality bounding the measure above 2/3 for all convex sets is the Kovner–Besicovitch inequality. The curve of constant width with the smallest possible Kovner–Besicovitch measure is the Reuleaux triangle.
Computational complexity
The Kovner–Besicovitch measure of any given convex polygon with vertices can be found in time by determining a translation of the reflection of the polygon that has the largest possible overlap with the unreflected polygon.
History
Branko Grünbaum writes that the Kovner–Besicovitch theorem was first published in Russian, in a 1935 textbook on the calculus of variations by Mikhail Lavrentyev and Lazar Lyusternik, where it was credited to Soviet mathematician and geophysicist . Additional proofs were given by Abram Samoilovitch Besicovitch and by István Fáry, who also proved that every minimizer of the Kovner–Besicovitch measure is a triangle.
See also
Estermann measure, a measure of central symmetry defined using supersets in place of subsets
References
External links
A Measure of Central Symmetry, Tanya Khovanova's Math Blog, September 2, 2012
Euclidean symmetries | Kovner–Besicovitch measure | [
"Physics",
"Mathematics"
] | 447 | [
"Functions and mappings",
"Euclidean symmetries",
"Mathematical objects",
"Mathematical relations",
"Symmetry"
] |
65,472,780 | https://en.wikipedia.org/wiki/Estermann%20measure | In plane geometry the Estermann measure is a number defined for any bounded convex set describing how close to being centrally symmetric it is. It is the ratio of areas between the given set and its smallest centrally symmetric convex superset. It is one for a set that is centrally symmetric, and less than one for sets whose closure is not centrally symmetric. It is invariant under affine transformations of the plane.
Properties
If is the center of symmetry of the smallest centrally-symmetric set containing a given convex body , then the centrally-symmetric set itself is the convex hull of the union of with its reflection across .
Minimizers
The shapes of minimum Estermann measure are the triangles, for which this measure is 1/2. The curve of constant width with the smallest possible Estermann measure is the Reuleaux triangle.
History
The Estermann measure is named after Theodor Estermann, who first proved in 1928 that this measure is always at least 1/2, and that a convex set with Estermann measure 1/2 must be a triangle. Subsequent proofs were given by Friedrich Wilhelm Levi, by István Fáry, and by Isaak Yaglom and Vladimir Boltyansky.
See also
Kovner–Besicovitch measure, a measure of central symmetry defined using subsets in place of supersets
References
Euclidean symmetries | Estermann measure | [
"Physics",
"Mathematics"
] | 275 | [
"Functions and mappings",
"Euclidean symmetries",
"Mathematical objects",
"Mathematical relations",
"Symmetry"
] |
66,765,338 | https://en.wikipedia.org/wiki/Red%20Bull%20Powertrains | Red Bull Powertrains, abbreviated as RBPT, is a Formula One power unit manufacturing company owned by the Austrian Red Bull GmbH and based in the United Kingdom. The company was formed in to take over the operation of Formula One power units developed by Honda from onwards following the Japanese manufacturer's withdrawal from the sport after 2021. Honda continued to support the Red Bull-owned teams in 2022 and will do so until the end of 2025. Honda assembles the power units and provides trackside and race operation support. The power units remain Honda's intellectual property, and due to a development freeze, Red Bull Powertrains will not develop them.
Red Bull Powertrains will take full responsibility for engine supply and operations from 2026, when the company will be renamed to Red Bull Ford Powertrains, following a partnership with Ford Motor Company. Red Bull Powertrains operates in a 5,000-square-foot facility near to the Red Bull Racing chassis department in Milton Keynes.
History
In February 2021, Red Bull Advanced Technologies signed an exclusive distribution agreement for Formula One engines with Honda to start in the 2022 season, after the Japanese automaker left Formula One at the end of the 2021 season. The engines will be purchased and renamed Red Bull Powertrains, and supplied to its two teams currently competing in Formula One, Red Bull Racing and AlphaTauri, starting in 2022.
On 23 April 2021 Red Bull Powertrains announced the hiring of Ben Hodgkinson as technical director. Hodgkinson had been head of mechanical engineering at Mercedes AMG High Performance Powertrains since 2017, and had worked at the Brixworth factory for 20 years. On 6 May 2021, Red Bull Racing announced the hiring of five more senior Mercedes engine employees: Steve Blewett (who will be the production director of the Red Bull power unit), Omid Mostaghimi (chief engine, electronics and energy recovery), Pip Clode (head of mechanical design for energy recovery), Anton Mayo (head of combustion power unit design) and Steve Brodie (leader of combustion engine operations). On 2 October 2022, Honda announced the extension of their technical support to Red Bull Racing until 2025. Honda's agreement with Red Bull Racing does not involve power unit development. Honda's logo will also appear on Red Bull Racing's and AlphaTauri's car from the 2022 Japanese Grand Prix onwards.
On 4 February 2023, Red Bull Racing and Ford Motor Company announced a strategic partnership that will see Ford return to Formula One in 2026 following new engine regulations. Ford will provide "expertise in areas including battery cell and electric motor technology as well as power unit control software and analytics" and "combustion engine development," and the company will be renamed to "Red Bull Ford Powertrains."
RBPTH001
The RBPTH001 was, despite its name, developed, produced, and maintained by Honda. It was a derivative of the Honda RA621H, with different ignition timing, cylinder pressure, and MGU-H to account for the new E10 fuels. The crankshaft and cylinder block geometry were also modified to ensure reliability when running on E10 fuels, and a specialised coating developed by Honda's motorcycle division was applied to the walls of the cylinders. The injection system, exhaust, and the turbocharger's compressor and turbine were all optimised for E10 fuel. The changes meant that the RBPTH001 weighed more than the RA621H, but the dimensions of the engines are virtually identical save for the exhaust and intake layout and the electrical components. The new engine could also run at noticeably higher temperatures compared to the RA621H. Despite the reduced energy density of the 2022 fuels, the RBPTH001 had greater thermal efficiency than its predecessor.
Formula One engine results
Notes
† – Retired before completion, but classified as more than 90% of the race distance was completed.
References
Formula One engine manufacturers
Red Bull Racing | Red Bull Powertrains | [
"Engineering"
] | 817 | [
"Automotive engineering",
"Automotive engineers"
] |
66,766,502 | https://en.wikipedia.org/wiki/Bill%20Sample | Bill Sample (born April 16, 1946) was a state legislator in Arkansas.
Career
A Republican, he served in the Arkansas Senate between 2011 and 2023, representing Hot Springs, after having served three terms in the Arkansas House of Representatives beginning in 2005. He lives near Village, Arkansas. In 2022, he was narrowly defeated in the Republican primary by county commissioner Matt McKee, who would go on to win the general election.
Sample owned a pest control business. He was a Vice President for the Arkansas Pest Management Association in 2004 after serving as Regional Director in 2002.
References
1946 births
Living people
Republican Party members of the Arkansas House of Representatives
21st-century members of the Arkansas General Assembly
People from Columbia County, Arkansas
Pest control
Republican Party Arkansas state senators | Bill Sample | [
"Biology"
] | 153 | [
"Pests (organism)",
"Pest control"
] |
66,768,301 | https://en.wikipedia.org/wiki/Global%20Partnership%20on%20Artificial%20Intelligence | The Global Partnership on Artificial Intelligence (GPAI, pronounced "gee-pay") is an international initiative established to guide the responsible development and use of artificial intelligence (AI) in a manner that respects human rights and the shared democratic values of its members. The partnership was first proposed by Canada and France at the 2018 44th G7 summit, and officially launched in June 2020. GPAI is hosted by the Organisation for Economic Co-operation and Development (OECD).
GPAI seeks to bridge the gap between theory and practice by supporting research and applied activities in areas that are directly relevant to policymakers in the realm of AI. It brings together experts from industry, civil society, governments, and academia to collaborate on the challenges and opportunities presented by artificial intelligence.
History
The Global Partnership on Artificial Intelligence was announced on the margins of the 2018 G7 Summit by Canadian Prime Minister Justin Trudeau and French President Emmanuel Macron. It officially launched on June 15, 2020 with fifteen founding members: Australia, Canada, France, Germany, India, Italy, Japan, Mexico, New Zealand, the Republic of Korea, Singapore, Slovenia, the United Kingdom, the United States, and the European Union.
The Organisation for Economic Co-operation and Development (OECD) hosts a dedicated secretariat to support GPAI's governing bodies and activities. UNESCO joined the partnership in December 2020 as an observer. On November 11, 2021, Czechia, Israel and few more EU countries also joined the GPAI, bringing the total membership to 25 countries. Since the November 2022 summit, the list of members stands at 29.
Austria, Chile, Finland, Malaysia, Norway, Slovakia and Switzerland were invited. The seven, however, are pending membership approval.
Membership
The following 29 members of the GPAI are:
Argentina
Australia
Belgium
Brazil
Canada
Czech Republic
Denmark
France
Germany
India
Ireland
Israel
Italy
Japan
Mexico
Netherlands
New Zealand
Poland
Republic of Korea
Senegal
Serbia
Singapore
Slovenia
Spain
Sweden
Turkey
United Kingdom
United States
European Union
Invited members:
Austria (pending membership approval)
Chile (pending membership approval)
Finland (pending membership approval)
Malaysia (pending membership approval)
Norway (pending membership approval)
Slovakia (pending membership approval)
Switzerland (pending membership approval)
Organization
GPAI's experts collaborate across several Working Groups themes: Responsible AI (including an ad-hoc subgroup on AI and Pandemic Response), Data Governance, Future of Work, and Innovation & Commercialization. GPAI's Working Groups are supported by two Centres of Expertise: one in Montreal that supports the first two Working Groups, and one in Paris that supports the latter two. It also has a Steering Committee, the elected chair of which has also been to date elected chair of the Multi Stakeholder Group (MEG). These chairs have been:
Jordan Zed and Baroness Joanna Shields (Shields, MEG chair; 2020-2021),
Joanna Shields and Renaud Vedel (Shields, MEG chair; 2021-2022),
Yoichi Iida and Inma Martinez (Martinez, MEG chair; 2023-2024)
GPAI has a rotating presidency and host (much like the G7). The presidencies to date have been:
(2020)
(2021)
(2022)
(2023)
References
External links
Artificial intelligence associations
Organizations established in 2020
Regulation of artificial intelligence | Global Partnership on Artificial Intelligence | [
"Technology"
] | 666 | [
"Computing and society",
"Regulation of artificial intelligence"
] |
66,768,404 | https://en.wikipedia.org/wiki/Candido%27s%20identity | __notoc__
Candido's identity, named after the Italian mathematician Giacomo Candido, is an identity for real numbers. It states that for two arbitrary real numbers and the following equality holds:
The identity however is not restricted to real numbers but holds in every commutative ring.
Candido originally devised the identity to prove the following identity for Fibonacci numbers:
Proof
A straightforward algebraic proof can be attained by simply completely expanding both sides of the equation. The identity however can also be interpreted geometrically. In this case it states that the area of square with side length equals twice the sum of areas of three squares with side lengths , and . This allows for the following proof due to Roger B. Nelsen:
.
Further reading
S. Melham: "'YE OLDE FIBONACCI CURIOSITY SHOPPE REVISITED". In: Fibonacci Quarterly, 2004, 2, pp. 155–160
Zvonko Cerin: "ON CANDIDO LIKE IDENTITIES". In: Fibonacci Quarterly, Volume 55, No. 5, 2017, pp. 46–51
Claudi Alsina, Roger B. Nelsen: "On Candido's Identity". In: Mathematics Magazine, Band 80, Nr. 3 (June, 2007), pp. 226-228 (JSTOR)
External links
Candido's identity at cut-the-knot.org
References
Algebraic identities
Fibonacci numbers
Articles containing proofs | Candido's identity | [
"Mathematics"
] | 302 | [
"Recurrence relations",
"Algebraic identities",
"Fibonacci numbers",
"Golden ratio",
"Mathematical relations",
"Articles containing proofs",
"Mathematical identities"
] |
66,768,914 | https://en.wikipedia.org/wiki/Space%20industry%20of%20India | India's Space Industry is predominantly driven by the national Indian Space Research Organisation (ISRO). The industry includes over 500 private suppliers and other various bodies of the Department of Space in all commercial, research and arbitrary regards. There are relatively few independent private agencies, though they have been gaining an increased role since the start of the 21st century. In 2023, the space industry of India accounted for $9 billion or 2%-3% of the global space industry and employed more than 45,000 people.
In 2021, the Government of India launched the Indian Space Association (ISpA) to open the Indian space industry to private sectors and start-ups. Several private companies like Larsen & Toubro, Nelco (Tata Group), OneWeb, MapmyIndia, Walchandnagar Industries are founding members of this organisation. Lieutenant General Anil Kumar Bhatt was appointed as the Director General of ISpA.
The Government of India forayed into space exploration when scientists started to launch sounding rockets from Thumba Equatorial Rocket Launching Station (TERLS), Thiruvananthapuram. The establishment of the space agency lead to the development of small launch vehicles SLV-3 and ASLV, followed by larger PSLV and GSLV rockets in the 90s, which allowed India to shift larger payloads and undertake commercial launches for the international market. Private firms started to emerge later as subcontractors for various rocket and satellite components. Reforms liberalising the space sector and nondisclosure agreements came in the late 2010s, leading to the emergence of various private spaceflight companies.
By 2019, India had launched more than 300 satellites for various foreign states. There were more than 40 startups in India in early 2021 in various stages of developing their own launch vehicles, designing satellites and other allied activities.
History
Early decades
India's interest in space travel began in the early 1960s, when scientists launched a Nike-Apache rocket from TERLS, Kerala. The Indian National Committee for Space Research was subsequently set up, which later became the Indian Space Research Organisation (ISRO) functioning under a new independent Department of Space (DoS) in the 1970s under the Prime Minister of India.
ISRO joined the Interkosmos program to launch its first satellite, Aryabhata, from the former Soviet Union in 1975.
SLV-3, a locally developed space rocket, was introduced in 1979, enabling India to undertake orbital launches. Experience gained from SLV-3 was used to develop an Augmented Satellite Launch Vehicle to develop technologies for launching satellites in geostationary orbit, but this ended up having very limited success and was eventually discontinued. However, the study of a homegrown medium-lift launch vehicle went on, which lead to the realisation of the Polar Satellite Launch Vehicle (PSLV).
Introduction of PSLV and commercial space missions
Antrix Corporation was set up in 1992 to market ISRO's technology, launch services and transfer technology to Indian private firms, dawning the commercial space sector in India. The PSLV rocket, introduced in 1993, enabled India to launch its polar satellites. Despite initial failures in its first two flights, PSLV had no further failures and emerged as ISRO's primary workhorse for launching domestic and foreign satellites. The development of GSLV and GSLV Mk III subsequently began in the 1990s and 2000s to attain the capability to launch communication satellites. However, the launchers didn't become operational until decades later, as India initially faced a great problem in the development of cryogenic engines. Later, NewSpace India Limited (NSIL) replaced Antrix as the commercial arm of ISRO.
Emergence of the private sector
The Indian space program emerged as an economic sector with government-backed investments with official institutions in the military and civilian administrations over decades of engineering. Over four decades, ISRO continued transferring technologies to small and medium enterprises (SMEs), leading to there being over 500 suppliers of various components in 2017.
India's IT industry started engaging in this sector in the 1990s. The Department of Space actively promoted the growth of the sector, leading to the establishment of the manufacturing of various systems. Large mapping projects for various civilian and military requirements were outsourced by the government, which drove the growth of India's private space sector. However, the private sector still played a supporting role, while the government continued to dominate the space sector.
In the late 2010s, a large number of startups started to emerge throughout the country with their own proposals and concepts to develop various satellite technologies and rockets.
A range of initiatives to deregulate the private space sector were introduced by Narendra Modi's cabinet in June 2020, and the Indian National Space Promotion and Authorisation Centre (INSPACe) was established for incubating technology into private firms, known as Non-Government Private Entities (NGPEs) by DOS. NGPEs were included as a crucial part of ISRO's Space Communication Policy draft issued in October 2020. As of 2021, a new Space Activities Bill and a space policy are being drafted by NALSAR Centre for Aerospace and Defence laws to regulate space manufacturing and the legal aspects of the industry in India.
An amendment was made in the FDI policy for space sector through a gazette notification dated April 16, 2024, called the Foreign Exchange Management (Non-debt Instruments) (Third Amendment) Rules, 2024. The liberalized entry routes under the amended policy are aimed at attracting potential investors in the Indian companies in space. As per them, up to 74 per cent FDI for satellite manufacturing & operation, satellite data products and ground segment & user segment are allowed under automatic route. Beyond 74 per cent these activities are under government route. FDI up to 49 per cent is allowed for launch vehicles and associated systems or subsystems, creation of spaceports for launching and receiving spacecraft are under automatic route but beyond 49 per cent government permission would be required. The cabinet on February 21 had allowed 74% foreign direct investment (FDI) under automatic route for satellite manufacturing, upto 49% under automatic route for launch vehicles, and upto 100% under automatic route for manufacturing of components and systems.
The new rules will come into effect from April 16 2024.
Throughout this time, various nondisclosure agreements and tech transfers have been taking place between ISRO and private entities.
In July 2024, Minister of Finance Nirmala Sitharaman announced that the Indian government will form a $119 million venture capital find for space startups in India. The Union Cabinet of India approved the creation of the venture capital fund in October 2024. India has more than 400 private space enterprises as of 2024, up from 54 in 2020.
Industry overview
ISRO and DoS continue to remain dominant in the national space sectFDr, having launched more than 100 domestic and more than 300 foreign satellites for 33 countries, while private firms have gradually been gaining ground. In 2019, the space industry of India accounted for $7 billion or 2% of the global space industry and employed more than 45,000 people. Antrix Corporation expects the industry to grow up to $50 billion by 2024 if provided with appropriate policy support.
In February 2020, there were 35 startups that came up in the space sector, of which three focused on designing rockets, 14 on designing satellites, and the rest on drone-based applications and services sector. The number further grew to over 40 in January 2021. Two companies, Skyroot Aerospace and AgniKul Cosmos, have tested their own engines and are in advanced stages of developing their own launch vehicles, while others have their launchers in the production pipeline and have launched satellites using ISRO rockets.
The space industry has contributed $60 billion to India's gross domestic product (GDP) between 2014 and 2024. It created 96,000 direct jobs and 4.7 million indirect jobs, according to the Socio-Economic Impact Analysis of Indian Space Programme Report. India now has the eighth-largest space economy in the world, with space sector earnings reaching $6.3 billion as of 2023.
The Indian economy has benefited from a multiplier effect of $2.54 for every dollar earned by the Indian space industry, according to the European consulting firm Novaspace, with India's space industry workforce being 2.5 times more productive than the country's wider industrial workforce. At a compound annual growth rate (CAGR) of 6%, the Indian space economy which is valued at approximately ₹6,700 crore ($8.4 billion) as of 2024 is projected to reach $13 billion by 2025, accounting for 2% to 3% of the worldwide space economy. The entire amount of money invested in ISRO over the past 55 years since its founding is less than NASA's annual budget. Compared to CNSA, which receives over $18 billion, and NASA, which works with a budget surpassing $25 billion, ISRO's annual budget in 2024 is approximately $1.6 billion.
India's space industry aims to focus on various niches in the space domain, which include retrieving space data, constructing small satellites and cheap launches into orbit.
List of notable companies
See also
List of private spaceflight companies
List of Indian satellites
List of foreign satellites launched by India
Commercialization of space
Space manufacturing
Space colonisation
Defence industry of India
Economy of India
References
Sources
Space industry
Space programme of India
Indian Space Research Organisation
Indian private spaceflight companies
Economy of India | Space industry of India | [
"Astronomy"
] | 1,930 | [
"Space industry",
"Outer space"
] |
66,769,197 | https://en.wikipedia.org/wiki/Sabine%20Werner | Sabine Werner (born 5 September 1960) is a German biochemist and professor.
Biography
Sabine Werner was born on 5 September 1960 in Tübingen, Germany. She attended Universities of Tubingen and Munich where she studied Biochemistry. Her PhD was in cancer research at the Max Planck Institute of Biochemistry, completed in 1989. Werner then went to the University of California San Francisco working on growth factor action and tissue repair. Werner took a position as group leader at the Max-Planck-Institute from 1993 to 1999 while also working as an Associate Professor in the Ludwig-Maximilians-University of Munich.In 1999 Werner became the Professor of Cell Biology at ETH Zürich. Werner was awarded the Pfizer Academic Award in 1998.
Research
Werner is known for her research on tissue regeneration, especially focusing on growth factors and reactive oxygen species. Her research has potential applications to the study of cancer.
Selected publications
Awards
Elected member, European Academy of Sciences (2020)
Elected member, European Molecular Biology Organization (2012)
Elected member, German National Academy of Sciences Leopoldina (2011)
Sources
German biochemists
1960 births
Living people
Scientists from Tübingen
Academic staff of ETH Zurich
Max Planck Society alumni | Sabine Werner | [
"Chemistry"
] | 236 | [
"Biochemistry stubs",
"Biochemists",
"Biochemist stubs"
] |
66,770,656 | https://en.wikipedia.org/wiki/Ipsita%20Roy | Ipsita Roy is a British-Indian materials scientist who is a professor at the University of Sheffield. Her research considers natural polymers of bacterial origin for medical applications. She was elected to the New York Academy of Sciences in 1997 and serves as the Editor of the Journal of Chemical Technology & Biotechnology.
Early life and education
Roy was an undergraduate student Delhi University. She was awarded a Inlaks Scholarship and the Overseas Research Students Award to complete her doctoral research at the University of Cambridge. Whilst at Cambridge, she was awarded the Churchill College Fellowship and the University of Cambridge Philosophical Society Fellowship. Roy was a postdoctoral student at the University of Minnesota, where she worked in fatty acid synthesis.
Research and career
Roy started her independent career at the Indian Institutes of Technology in 1996, where she started to explore biodegradable polymers, which she formed from Streptomyces. After four years as an assistant professor at the IIT, Roy moved to the United Kingdom, where she joined the University of Westminster. She led the Applied Biotechnology Research Group in the School of Life Sciences. Roy moved to the University of Sheffield in 2019, where she is Professor of Biomaterials.
Roy investigates polyhydroxyalkanoates (PHAs), biocompatible, biodegradable polymers that are produced by bacteria. She has shown it is possible to form PHAs from Gram-positive bacteria which do not degrade into acidic products like polylactic acid or PLGA. At the same time, PHAs do not degrade in the bulk but on the surface, making them more stable than other biopolymers. Such polymers exist at two different molecular weights, which have very different materials properties; with short-chains being brittle and mid length chains being elastomeric. In regenerative medicine, PHAs with precise molecular weights can be used for different tissue types. This makes PHAs useful for medical applications such as tissue engineering and wound healing.
Roy has worked alongside Sian Harding, Carolyn Carr and Molly Stevens at Imperial College London on the design of cardiac patches based on PHAs as platforms for cell engraftment and the controlled delivery of pharmaceuticals using PHA microspheres.
Selected publications
References
Living people
Year of birth missing (living people)
Women materials scientists and engineers
Academics of the University of Sheffield
Delhi University alumni
Alumni of the University of Cambridge | Ipsita Roy | [
"Materials_science",
"Technology"
] | 477 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
66,771,918 | https://en.wikipedia.org/wiki/Tissiflashmob | Tissiflashmob (Finnish for "tits flash mob") was a demonstration organised by Sandra Marins and Säde Vallarén, which was held for the first time in June 2019 at the Hietaniemi beach in Helsinki, Finland. The organisers held the demonstration in criticism for a previous event where a woman had been removed from a beach for sunbathing topless.
The demonstration was held for a second time in 2020 in eight different cities and also online. This time the demonstration was held by the feminist activist group Cult Cunth.
References
Demonstrations
Nudity
Feminist protests
2019 in Finland
2020 in Finland
2010s in Helsinki
2020s in Helsinki
Feminism in Finland
Events in Helsinki
Protests in Finland
2019 protests
2020 protests
Breast
Sun tanning
Flash mob
Finnish words and phrases
2019 in women's history
2020 in women's history | Tissiflashmob | [
"Chemistry"
] | 170 | [
"Sun tanning",
"Ultraviolet radiation"
] |
66,771,994 | https://en.wikipedia.org/wiki/Chemical%20Society%20of%20Nigeria | The Chemical Society of Nigeria is the professional organisation supporting the chemical sciences in Nigeria and a learned society promoting the science and practice of chemistry.
The Pan Africa Chemistry Network has a center of excellence in analytical chemistry in Nigeria.
References
Chemistry societies
Chemistry education | Chemical Society of Nigeria | [
"Chemistry"
] | 50 | [
"Chemistry societies",
"nan",
"Chemistry organization stubs"
] |
66,773,986 | https://en.wikipedia.org/wiki/Agreeable%20subset | An agreeable subset is a subset of items that is considered, by all people in a certain group, to be at least as good as its complement. Finding a small agreeable subset is a problem in computational social choice.
An example situation in which this problem arises is when a family goes on a trip and has to decide which items to take. Since their car is limited in size, they cannot pick all items, so they have to agree on a subset of items which are most important. If they manage to find a subset of items such that all family members agree that it is at least as good as the subset of items remaining at home, then this subset is called agreeable.
Another use case is when the citizens in some city want to elect a committee from a given pool of candidates, such that all citizens agree that the subset of elected candidates is at least as good as the subset of non-elected ones. Subject to that, the committee size should be as small as possible.
Definitions
Agreeable subset
There is a set S containing m objects. There are n agents who have to choose a subset of S. Each agent is characterized by a preference-relation on subsets of S. The preference-relation is assumed to be monotone - an agent always weakly prefers a set to all its subsets. A subset T of S is called agreeable if all agents prefer T to S\T.
If an agent's preference relation is represented by a subadditive utility function u, then for any agreeable subset T, u(T) ≥ u(S)/2.
As an example, suppose there are two objects - bread and wine, and two agents - Alice and George. The preference-relation of Alice is {bread,wine} > {bread} > {wine} > {}. If the preference-relation of George is the same, then there are two agreeable subsets: {bread,wine} and {bread}. But if George's preference-relation is {bread,wine} > {wine} > {bread} > {}, then the only agreeable subset is {bread,wine}.
Necessarily-agreeable subset
If the agents' preference relations on the subsets are given, it is easy to check whether a subset is agreeable. But often, only the agents' preference relations on individual objects are given. In this case, it is often assumed that the agents' preferences are not only monotone but also responsive. A subset T of S is called necessarily agreeable if all agents prefer T to S\T according to the responsive set extension of their preferences on individual objects.
A closely related property of subsets is:
(*) For every k in 1, ..., m, the subset T contains at least k/2 of the best k objects for agent i.
To satisfy property (*), the subset T should contain the best object in S; at least two of the three best objects in S; at least three of the five best objects in S; etc.
If a subset T satisfies (*) for all agents, then it is necessarily-agreeable. The converse implication holds if the agents' preference relations on indivisible objects are strict.
Worst-case bounds on agreeable subset size
What is the smallest agreeable subset that we can find?
Agreeable subsets
Consider first a single agent. In some cases, an agreeable subset should contain at least objects. An example is when all m objects are identical. Moreover, there always exists an agreeable subset containing objects. This follows from the following lemma:
For every agent i, if two subses V1 and V2 are disjoint, then at least one of S\V1 or S\V2 is agreeable to i.
(this is because S\V1 contains V2 and S\V2 contains V1 and the preferences are monotone).
This can be generalized: For any n agents and m objects, there always exists an agreeable subset of size , and it is tight (for some preferences this is the smallest size of an agreeable subset). The proof for two agents is constructive. The proof for n agents uses a Kneser graph. Let , and let G be the Kneser graph , that is, the graph whose vertices are all subsets of m-k objects, and two subsets are connected iff they are disjoint. If there is a vertex V such that all agents prefer S\V to V, then S\V is an agreeable subset of size k. Otherwise, we can define a color for each agent and color each vertex V of G with an agent who prefers V to S\V. By the theorem on chromatic number of Kneser graphs, the chromatic number of G is ; this means that, in the n-coloring just defined, there are two adjacent vertices with the same color. In other words, there are two disjoint subsets such that, a single agent i prefers each of them to its complement. But this contradicts the above lemma. Hence there must be an agreeable subset of size k.
When there are at most three agents, and their preferences are responsive, an agreeable subset of size can be computed in polynomial time, using polynomially-many queries of the form "which of these two subsets is better?".
When there are any number of agents with additive utilities, or a constant number of agents with monotone utilities, an agreeable subset of size can be found in polynomial time using results from consensus halving.
Necessarily-agreeable subsets
When there are two agents with responsive preferences, a necessarily-agreeable subset of size exists and can be computed in polynomial time.
When there are n ≥ 3 agents with responsive preferences, a necessarily-agreeable subset of this size might not exist. However, there always exists a necessarily-agreeable subset of size , and such a set can be computed in polynomial time. On the other hand, for every m which is a power of 3, there exist ordinal preferences of 3 agents such that every necessarily-agreeable subset has size at least . Both proofs use theorems on Discrepancy of permutations.
There exists a randomized algorithm that computes a necessarily-agreeable subset of size .
Computing a smallest agreeable subset
In many cases, there may exist an agreeable subset that is much smaller than the worst-case upper bound.
For agents with general monotone preferences, there is no algorithm that computes a smallest agreeable set using a polynomial number of queries. Moreover, for every constant c, there is no algorithm that makes at most mc/8 queries and finds an agreeable subset with expected size at most m/(c log m) of the minimum, even with only one agent. This is tight: there exists a polynomial-time algorithm that finds an agreeable subset with size at most O(m / log m) of the minimum.
Even for agents with additive utilities, deciding whether there exists an agreeable subset of size m/2 is NP-hard; the proof is by reduction from the balanced partition problem. For any fixed of additive agents, there exists a pseudopolynomial time for this problem; but if the number of agents is not fixed, then the problem is strongly NP-hard. There exists a polynomial-time O(log n) approximation algorithm.
Extensions
The agreeable subset problem was studied with additional constraint represented by a matroid.
See also
Envy-free item allocation
Participatory budgeting algorithm
Multiwinner elections
Consensus halving
Fair division among groups - a variant of fair division in which the pieces of the resource are given to pre-determined groups rather than to individuals.
References
Fair item allocation
Social choice theory
Discrepancy theory | Agreeable subset | [
"Mathematics"
] | 1,610 | [
"Discrepancy theory",
"Combinatorics"
] |
66,774,284 | https://en.wikipedia.org/wiki/RN-9893 | RN-9893 is a drug which acts as a potent and selective blocker of the TRPV4 ion channel. It has been used to investigate the role of TRPV4 channels in the function of heart valves.
See also
HC-067047
SET2
References
Piperazines
Nitrobenzene derivatives
Sulfonamides
Amides
Isopropyl compounds
Trifluoromethyl compounds | RN-9893 | [
"Chemistry"
] | 86 | [
"Pharmacology",
"Functional groups",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Amides"
] |
66,774,578 | https://en.wikipedia.org/wiki/Direct%20laser%20interference%20patterning | In materials science, Direct Laser Interference Patterning (DLIP) is a laser-based technology that uses the physical principle of interference of high-intensity, coherent laser pulses to produce functional periodic microstructures. To achieve interference, the beam is divided by a beam splitter, specialized prisms, or other elements. The beams are then overlapped on amaterial surface to form an interference pattern. If the power of the laser beam is sufficiently high, material removal can occur at the interference maxima through processes such as remelting, evaporation and ablation, while the material at the interference minima remains mostly intact. In this way, a large variety of periodic patterns can be created on the surface of the material. Depending on the lasers used, DLIP can be applied to almost any material and can change the properties of surfaces in many technological areas with regard to electrical and optical properties, tribology (friction and wear), light absorption and wettability.
History
In the 1990s, Frank Mücklich learned about Martin Stutzmann's method for local crystallization of amorphous layers from him at the Technical University of Munich. The method he utilized was based on the interference principle using laser radiation. Mücklich, who had already gained intensive theoretical and experimental experience with interference phenomena during his doctorate, decided to use it by applying high laser intensity for the development of local and periodic variation of the microstructure due to metallurgical effects. With the help of funding he got from the Alfried Krupp sponsorship in 1997, he was able to realise this concept in the laboratories of his Chair for Functional Materials at Saarland University, by acquiring a nanosecond laser and the necessary optical equipment.
What was noticeable in the experiments, however, was that in addition to the local metallurgical effects observed, i.e. microstructural changes in the material (like grain size distribution, orientation), also the micro-topography of the surface could be controlled. Furthermore, the geometry of the periodic pattern depended on the number of interfering laser beams, their angle with respect to the materia’s surface and the beam polarization. In this way, the history of Direct Laser Interference Patterning started.
Inspired by Nachtigall's bionics research, the joint idea initially arose of reproducing the surface structures that were typical in living natural systems and evolutionarily optimised for the respective "functionalities" in plants and animals within the framework of the interdisciplinary research topic of "Biologically Composed Materials". The work with his doctoral student at the time, Andrés Lasagni, was particularly inspiring and achieved rapid successes: in 2006, Lasagni received his doctorate as the best doctoral student of the year for structuring by laser interference metallurgy in the micro/nano range ("Advanced design of periodical structures by laser interference metallurgy in the micro/nano scale on macroscopic areas"). For their successful publications, the jury of the International Journal of Materials Research - IJMR awarded Frank Mücklich, Andrés Lasagni and Claus Daniel the Werner Koester Prize of the DGM.
In 2008, after his postdoctoral stay as a Humboldt Fellow in the USA, Lasagni returned to Germany with a Fraunhofer Attract Grant and established a research team on "Surface Functionalization" at the Fraunhofer IWS, in Dresden. There he developed many compact optics which are crucial for the robust application of today's DLIP technology, while Mücklich and his team in Saarbrücken continued to open up new materials engineering application fields for surface functionalisation through DLIP and in 2009 opened the Material Engineering Center Saarland, where direct industry collaborations promoted the technology transfer.
In 2013, Andrés Lasagni received the DGM's Masing Memorial Award for his extraordinary achievements.
Later in 2016, Mücklich’s and Lasagni’s teams were awarded the Berthold Leibinger Innovation Prize for the development of direct laser interference patterning (DLIP) for their joint innovative laser technology platform and uniquely successful cooperation.
Together with Dominik Britz and Ralf Zastrau, Mücklich and Lasagni founded the company SurFunction GmbH to commercialise the technology on the market for the first time.
Pros and Cons of the method
DLIP offers several advantages and disadvantages compared to other methods for the creation of defined micropatterns:
Advantages:
Compared to direct laser writing (DLW) where a laser beam creates each surface feature individually, DLIP can create thousands of surface features (e.g. dots, pillars, lines) with a single laser pulse and can therefore realize much faster process speeds.
Since the size of the surface features is determined by the shape of the interference pattern, the ability to focus the laser beam as a whole (Abbe limit) does not present a limiting factor. This makes it possible to create features in the micrometer and sub-micrometer range. For instance, line structures with spatial periods as small as 180 nm were achieved in DLC coatings using UV laser radiation.
DLIP is a single step technique that can be implemented "in-line" without the need for extensive pre- or post-treatment.
Disadvantages:
To ensure controlled interference between the laser beams, it is crucial that these beams are coherent. This requirement makes the design of the optical setup for DLIP relatively challenging, as disturbances to one or more sub-beams can lead to a loss of coherence, causing distortions in the interference pattern or even its complete loss.
As DLIP is ideally used to pattern relatively large areas per laser pulse (compared to DLW), the lasers used generally require relatively high pulse energies, which can make them comparatively expensive to acquire.
Types of beam splitters
The coherent laser beams required for the technique are generally produced by splitting a primary beam into two or more sub-beams. As both beams originate from the same source, coherence is ensured as long as the subsequent optics do not disturb it.
There are a variety of methods to split the primary laser beam:
prisms
laser beam dividers
diffraction gratings
DOEs (diffractive optical elements)
Lloyd (based on perpendicularly placed and connected mirrors)
The process
Figuratively, the electromagnetic waves of a laser beam can overlap similar to water waves, forming intensity patterns. This principle is called interference. If a wave crest of the first propagating wave meets a wave crest of the overlapping, second wave, this results in the formation of a larger wave, called constructive interference. If a wave trough meets a wave crest, this results in the extinction of the wave, called destructive interference.
In this way, overlapping coherent laser beams are used to create intensity patterns that are projected onto a component surface. The material is melted or evaporated in areas of constructive interference, depending on the pulse length, while it remains almost unaffected in areas of destructive interference. The number and arrangement of the beams in relation to each other determines the type of pattern applied. This can be, for example, a line pattern, cross pattern, dot pattern or almost any periodic surface texture.
Higher complexities of surface patterns can be created with an increasing number of beams. The angle between the overlapping laser beams and the wavelength of the used laser determine the structure size (period) of the applied periodic intensity distribution.
In contrast to other laser-based processing methods, such as direct laser writing, the laser beam diameter has not to be focused. This means that a significantly larger area can be processed per laser pulse. At the same time, microscopic small structures, which are even smaller than the diffraction limit (which determines the smallest possible beam diameter at the focal position), can be created quickly and without contact.
Therefore, DLIP combined with a high-frequency laser, can achieve throughputs in the range of >1 m2/min.
The DLIP process has a very high depth of focus compared to laser writing, as DLIP does not rely on precise focusing of the laser beam, but creates an "interference volume" within which the surface is equally structured with the corresponding interference pattern.
DLIP offers a effectively infinite variety of structuring possibilities through the use of nano-, pico- or femtosecond lasers, as well as by varying the number of used interfering laser beams, their geometrical configuration as well as the wavelength of the radiation used.
Prominent research projects
More than 500 publications (as of 2022) have been published on research involving DLIP technology.
Projects related to research in space are an important topic area to investigate the potential for the hygienic properties of surface texturing by DLIP. The impact of biofilms is greater in space than on Earth because, on the one hand, crew life and mission success depend on the nominal operation of mechanical systems, which can be interrupted by material damage associated with biofilm growth, and, on the other hand, the isolated, confined environment of spaceflight can increase disease transmission rates. In the case of the International Space Station (ISS), biofilms are a problem of the Environmental Control and Life Support System (ECLSS), in particular the Water Processor Unit (WPA). The aim is to understand the behaviour of microorganisms and the formation of biofilms, since they have an impact on the health (of the astronauts) as well as the fact that biofilms lead to material damage, which should be minimised for reasons of sustainability and to improve the longevity of products and materials in industry and in many sectors also on Earth.
The following space projects in cooperation with NASA and ESA received special media attention:
Touching surfaces (Testing antimicrobial surfaces for space-flight and earth applications): In this experiment, novel surfaces with and without active antimicrobial properties are being tested for their antimicrobial efficacy under space conditions in combination with bacteria contact-control surface structuring by DLIP. The contact surfaces were touched by astronauts on board the ISS. The microbes on them will then be examined on Earth with regard to biofilm formation.
Biofilms (Testing Laser Structured Antimicrobial Surfaces Under Space Conditions): The BIOFILMS project investigates biofilm formation on various antimicrobial surfaces under space conditions. These surfaces consist of different metals with and without active bactericidal properties, which were additionally surface-structured by ultra-short pulsed DLIP on the scale of single bacterial cells. In this way, the bacterial strains used in the experiment are offered improved or worsened contact conditions. The influence of these surface properties on bacterial biofilm formation is thereby investigated in the context of variable gravity by rotation in a centrifuge within the ISS for the Moon, Mars and Earth."
Space Biofilms: In late 2019, the Space Biofilms experiment launched to the ISS to investigate the specifics of biofilms formed in space compared to their corresponding counterpart on Earth. In addition to the expression of antimicrobial resistance genes, novel materials, including those based on DLIP technology, were tested here as potential biofilm containment strategies for future critical ECLSS components.
ConTACTS Concordia: The Concordia experiment ConTACTS is designed to analyse antimicrobial surfaces as a strategy to reduce the microbial load on contact surfaces and actively track microbial spread. The Concordia Station in Antarctica serves here as a model environment within the hibernation phase of several months in the Arctic winter to investigate the special conditions within spatially closed artificial habitats. In the ConTACTS Concordia project, sample carriers with antimicrobial functionalised surfaces are placed in different areas of Concordia Station during the wintering period of several months. These locations are expected to vary in their environmental conditions, such as temperature and humidity, and in the frequency of human presence. The touch arrays include antimicrobial copper-based metallic surfaces with and without additional topographic surface texturing with DLIP. The surfaces are be exposed to both direct daily contact and pure airflow exposure in different atmospherically varying areas of the station. The properties produced by DLIP are expected to remain intact despite the extreme environmental conditions. The project helps to understand microbial dispersal in enclosed habitats, including through frequently touched surfaces, and to test optimised containment strategies.
Other prominent projects:
Photovoltaic project by Fraunhofer IWS and IAPP: In order to enhance the efficiency of thin film photovoltaic systems, flexible polymer materials were textured by DLIP in 2011, reaching an enhanced electrical performance of 21% compared to untreated foils. This improvement was possible due to the produced periodic structure, which increases the optical path in to the active material of the cells. Thus, DLIP was identified to have a great potential for the development of high-efficiency solar cells for organic as well as other thin-film solar technologies.
Prizes related to DLIP
Masing Memorial Prize 2020 to Andreas Rosenkranz
Transfer Prize of the Steinbeis Foundation | Löhn Prize (2019) to Mücklich and the Material Engineering Center Saarland (MECS) together with TE Connectivity
Materials Science and Technology Prize of the FEMS (2017) to Andrés Lasagni
Berthold Leibinger Innovation Prize (2016) to the Direct Laser Interference Patterning project groups of Mücklich and Lasagni for the best laser innovation
Masing Memorial Prize 2012 to Andrés Lasagni
German High Tech Champions Award (2011) to Andrés Lasagni for research on increasing the efficiency of photovoltaic systems
Werner Köster Prize (2006) to Frank Mücklich, Andrés Lasagni and Claus Daniel for the best publication of the year in the International Journal of Materials Research
Fraunhofer Attract Award to Andrés Lasagni for "Micro/nano" Fabrication of Surface Architectures using Direct Laser Interference Patterning
References
Materials science | Direct laser interference patterning | [
"Physics",
"Materials_science",
"Engineering"
] | 2,831 | [
"Applied and interdisciplinary physics",
"Materials science",
"nan"
] |
66,775,160 | https://en.wikipedia.org/wiki/Discovery%20system%20%28AI%20research%29 | A discovery system is an artificial intelligence system that attempts to discover new scientific concepts or laws. The aim of discovery systems is to automate scientific data analysis and the scientific discovery process. Ideally, an artificial intelligence system should be able to search systematically through the space of all possible hypotheses and yield the hypothesis - or set of equally likely hypotheses - that best describes the complex patterns in data.
During the era known as the second AI summer (approximately 1978-1987), various systems akin to the era's dominant expert systems were developed to tackle the problem of extracting scientific hypotheses from data, with or without interacting with a human scientist. These systems included Autoclass, Automated Mathematician, Eurisko, which aimed at general-purpose hypothesis discovery, and more specific systems such as Dalton, which uncovers molecular properties from data.
The dream of building systems that discover scientific hypotheses was pushed to the background with the second AI winter and the subsequent resurgence of subsymbolic methods such as neural networks. Subsymbolic methods emphasize prediction over explanation, and yield models which works well but are difficult or impossible to explain which has earned them the name black box AI. A black-box model cannot be considered a scientific hypothesis, and this development has even led some researchers to suggest that the traditional aim of science - to uncover hypotheses and theories about the structure of reality - is obsolete. Other researchers disagree and argue that subsymbolic methods are useful in many cases, just not for generating scientific theories.
Discovery systems from the 1970s and 1980s
Autoclass was a Bayesian Classification System written in 1986
Automated Mathematician was one of the earliest successful discovery systems. It was written in 1977 and worked by generating a modifying small Lisp programs
Eurisko was a Sequel to Automated Mathematician written in 1984
Dalton is a still maintained program capable of calculating various molecular properties initially launched in 1983 and available in open source since 2017
Glauber is a scientific discovery method written in the context of computational philosophy of science launched in 1983
Modern discovery systems (2009–present)
After a couple of decades with little interest in discovery systems, the interest in using AI to uncover natural laws and scientific explanations was renewed by the work of Michael Schmidt, then a PhD student in Computational Biology at Cornell University. Schmidt and his advisor, Hod Lipson, invented Eureqa, which they described as a symbolic regression approach to "distilling free-form natural laws from experimental data". This work effectively demonstrated that symbolic regression was a promising way forward for AI-driven scientific discovery.
Since 2009, symbolic regression has matured further, and today, various commercial and open source systems are actively used in scientific research. Notable examples include Eureqa, now a part of DataRobot AI Cloud Platform, AI Feynman, and QLattice.
References
External links
The AI revolution in scientific research
Applications of artificial intelligence
Data mining
Machine learning | Discovery system (AI research) | [
"Engineering"
] | 595 | [
"Artificial intelligence engineering",
"Machine learning"
] |
66,775,226 | https://en.wikipedia.org/wiki/Marl%20lake | A marl lake is a type of alkaline lake whose bottom sediments include large deposits of marl, a mixture of clay and carbonate minerals. The term is particularly applied to lakes that have been dredged or mined for marl, often for manufacturing Portland cement.
Marl lakes are found around the Great Lakes of North America, in Britain, and in other areas that were once glaciated. They support distinctive ecological communities that are vulnerable to damage from silting, nutrient pollution, drainage, and invasive species.
Description
Marl lakes typically are found in areas that were recently glaciated, and they often fill kettle depressions left behind by melting glaciers. Their most distinctive characteristic is that they deposit sediments rich in calcium carbonate. More precisely, a marl lake is a lake in which calcium carbonate makes up at least 50% of the dry weight of the inorganic fraction of the surface sediments. In some lakes, the sediments are almost pure calcium carbonate.
The calcium carbonate precipitates from lake water that is alkaline, typically with a pH 8.0 or greater, and has a high concentration of divalent ions and is low in dissolved organic compounds. The concentration of calcium carbonate in the lake water usually exceeds 100 mg per liter. Young marl lakes are sometimes visually stunning, with very fine suspended crystals of calcium carbonate giving the water an opaque light blue color.
In Britain, marl lakes are of glacial origin and are shallow (less than deep). They are associated with carbonate bedrock or bedrock of the Old Red Sandstone. Their concentration of calcium carbonate is 140 mg/L, typical of temperate limestone groundwater.
The precipitation of calcium carbonate from marl lakes is a consequence of removal of carbon dioxide by photosynthesis (particularly by Chara, stonewort, which becomes encrusted with low-magnesium calcite during the summer) or outgassing of saturated groundwater, or as a result of the common-ion effect.
Higgins Lake, in central Michigan, US, is the only known location of freshwater oolites. These are found in a narrow band between a beach rich in clastic sediments and deeper water below wave base.
Ecology
Marl lakes of the upper Great Lakes region have a very low biological productivity. They typically are very sparse in macrophytes (macroscopic plants and algae), and their productivity is dominated by one macrophyte species, Scirpus subterminalis (water bulrush), which is responsible for an average of 79% of the total biomass. Chara (stonewort) accounts for 12% of the biomass but limited to the most shallow, protected parts of the lake. Potamogeton (pondweed) provides most of the remaining biomass.
Marl lakes often contain lakemounts. These are thought to begin with thin patches in the original kettle ice, which were colonized by Najas, Potamogeton, and Chara. These locally enhanced the sediment deposition rate to build up the lakemounts to near the lake surface. The lakes are often surrounded by beachrock composed of cemented pisoliths (calcite concretions) and gastropod shells. The shallow beachrock slopes are inhabited by Chara.
British marl lakes are dominated by Chara, which is the source of the marl. By contrast with marl lakes of the Great Lakes region, they have a rich emergent and submerged macrophyte community. They are also home to many gastropods and crustaceans.
Iron is a limiting nutrient in marl lakes, as it is practically insoluble in oxygenated, alkaline water. To be available at all, it must be chelated by organic matter. But because the primary productivity is low, organic matter is scarce; this means there is little chelation of iron, which keeps primary productivity low in a vicious cycle. Phosphate, another essential nutrient, is precipitated along with carbonates, further reducing the supply of nutrients.
Some mare lakes are meromictic lakes in which bottom water never mixes with surface water. Green Lake, at Fayetteville, New York, is a meromictic marl lake containing a cyanobacterial thrombolitic bioherm.
Marl lakes are ecologically important, but are vulnerable to damage by silting, nutrient pollution, drainage, and invasive species. To some extent, the high calcium content of marl lake water buffers it against phosphate, but the native ecological community is sensitive even to small changes in chemistry and the introduction of nutrient pollution renders the lake more hospitable to invasive species. Eventually a threshold is reached at which the lake rapidly loses its marl characteristics and flowering plants replace Chara. In Britain, only the marl lakes of the more remote parts of northern Scotland are likely to remain pristine into the near future. Many are transient or eutrophic, and at least half those in Britain have been affected by nutrient pollution.
As records of climate changes
Marl ponds steadily deposit sediments that can be dated by carbon-14. They also contain proxies for local climate. For example, the sediments of Pretty Lake in Indiana, USA, contain chlorophyll degradation products from which its history of biological productivity can be estimated. This record shows a peak in productivity during the Boreal Age (9 to 7.6 thousand years ago) and another peak at about 6000 years ago.
Wallywash Great Pond in Jamaica is an unusual tropical marl lake whose sediments also record climate fluctuations. Cores of the bottom sediments show deposition of marls during wet periods and sea highstands; organic-rich sediments during intervals of swampy conditions; and calcareous brown mud suggesting periods when the pond was an ephemeral lake. These cores record climate from the last interglacial, around 120,000 years ago, to nearly the present.
Exploitation
The carbonate-rich sediments deposited by marl lakes is a mixture of clay and carbonate minerals described as marl. Marl lakes have frequently been dredged or mined for marl, often used for manufacturing Portland cement.
References
Glacial landforms
Lakes | Marl lake | [
"Environmental_science"
] | 1,246 | [
"Lakes",
"Hydrology"
] |
66,775,515 | https://en.wikipedia.org/wiki/Nikolaev%20Institute%20of%20Inorganic%20Chemistry | Nikolaev Institute of Inorganic Chemistry of the Siberian Branch of the RAS () is a research institute in Akademgorodok, Novosibirsk, Russia. It was founded in 1957.
Activities
Its field includes the chemistry of inorganic compounds, chemical thermodynamics of inorganic systems, crystal chemistry and electronic structure of inorganic substances.
References
Research institutes in Novosibirsk
1957 establishments in the Soviet Union
Research institutes established in 1957
Inorganic chemistry
Research institutes in the Soviet Union
Chemical research institutes | Nikolaev Institute of Inorganic Chemistry | [
"Chemistry"
] | 101 | [
"nan",
"Chemical research institutes",
"Chemistry organization stubs"
] |
78,383,621 | https://en.wikipedia.org/wiki/TOI-6883%20b | TOI-6883 b is a Jupiter-like extrasolar planet orbiting TOI-6883, a Sun-like star in the Delphinus constellation 307 light years (94.17 pc) from Earth.
Discovery
It was discovered in 2024 by Italian amateur astronomers Giuseppe Conzo and Mara Moriconi using the transit method with TESS data. At the beginning, a single transit event was identified, so the extrasolar planet was first classified as a candidate with TOI-6883.01 nomenclature. The discovery describes a planet with a radius of 1.087 times that of Jupiter, but without details of the orbital period.
The planet was confirmed by the professional astronomers of SETI team led by Lauren Sgro, who fully characterised it using the radial velocity method and the orbital period was identified. TOI-6883 b revolves around its star in about 16.25 days at a distance of 0.123 AU (astronomical units) with a very eccentric orbit.
See also
HD 80606 b
Upsilon Andromedae b
Hot Jupiter
References
External links
NASA – TESS Mission
TOI-6883 b at The Extrasolar Planets Encyclopaedia
TIC 393818343 b at NASA Exoplanet Archive
Delphinus
Exoplanets discovered in 2024
Transiting exoplanets
Exoplanets discovered by TESS | TOI-6883 b | [
"Astronomy"
] | 284 | [
"Delphinus",
"Constellations"
] |
78,384,104 | https://en.wikipedia.org/wiki/Kodak%20Komstar | The Kodak Komstar is a laser beam-based, dry-processing micrographics system made by the Eastman Kodak Company that enables computer output microfilm and microfiche (COM) from either a magnetic tape reel or via direct connection to an IBM System/370 mainframe. Introduced in 1977, the product line consisted of three models, the Komstar 100, 200, and 300. It remained in use at customer sites into the 1990s.
Background
Kodak's previous COM offering was the KOM 90, an off-line wet-solution system. It was most suitable for COM uses involving large reports that were not intended for immediate reading or that were intended to go straight to archival storage. Moreover, KOM 90 found resistance from customers who did not want to bring it into raised-floor computer rooms for fear the processing chemicals would leak out and damage wiring and cabling underneath the floor.
Product line
The Komstar was introduced in 1977. Unlike its predecessor, the Komstar employed a laser beam and a dry processing approach using Kodak's new Recordak Dacomatic DL SO-030 film. It worked by moving the laser beam to compose characters in a 7-by-9 point matrix, then write the columns of the matrix onto the film while proceeding line by line through a page. It could produce either 105mm microfiche or 16mm microfilm.
The Komstar was intended to require minimal supervision on the part of computer operators. Compared to wet-solution systems, it represented a considerable labor simplification and also allowed units to be placed in computer rooms without worry, with one customer reporting that it occupied only a third of the space as before.
The Komstar product line was available in three models:
Komstar 100 – operates on-line in an IBM System/370 environment, controlled by Kodak Starlink I or II software running on the IBM mainframe;
Komstar 200 – operates on-line in an IBM System/370 environment, controlled by Kodak Starlink III software running on the Komstar's internal processor;
Komstar 300 – operates off-line, using a magnetic tape reel as input.
All three models were priced at over $100,000. The software was included with the hardware purchase.
Use with IBM mainframes
The Komstar could be connected to an IBM System/370 via byte-multiplexer, block-multiplexor, or selector. The Starlink software was built to mimic the interface characteristics of an IBM line printer, and came with its own User's Guide. Training to customers who needed to program to, or operate, the Komstar and the Starlink software was conducted in Kodak training centers in various cities.
As with a printer, the Komstar made use of IBM's forms control buffer (FCB) mechanism; IBM mainframe shops might store the source for the forms control information used to build FCB images for both their printer and the Komstar into their own partitioned data set such as ACME.SOURCE.FCBIMAGE, while load modules would go into SYS1.IMAGELIB. The Komstar system also had the ability to be directed with respect to forms overlay, line spacing, and character spacing, and for the Komstar 200, the ability to format print files on its processor instead of on the mainframe. Shops might create their own programmer catalogued procedures such as FCBIMAGE to encapsulate some of these choices and operations.
The Komstar was immediately compatible with follow-on systems in the IBM mainframe environment, such as the IBM 4300 series. It was also possible to spool print files to the Komstar from other IBM computer systems, such as the midrange IBM System/34 and distributed IBM 8100 systems.
Ongoing product
The Komstar was manufactured by the Kodak Apparatus Division in Rochester, New York. The division was not located at the well-known Kodak Park complex, but rather at the separate-but-also-large Elmgrove site. Some progressive management techniques were used there, including workers taking greater responsibility for planning decisions; they signed the individual Komstar machines they made and entered into discussions with the customers using those particular machines.
In May 1985, the Komstar Microimage Processor IV was announced. which was billed as a fourth-generation solution. It could write barcodes on microfiche masters and use those to generate duplicate and collated microfiche. That processing was done inline within the mainframe environment, and the Komstar equipment could generate them at the rate of 1,800 per hour.
COM equipment was often used together with computer aided retrieval (CAR) systems, and Kodak's offerings in that domain were known as "KAR". In 1985, the KAR-8800 was announced. An earlier CAR capability was part of the Kodak Oracle product.
Despite the microform industry having become low growth by the early 1990s, the Komstar product line was a profitable one for Kodak. It was still being manufactured into those early 1990s, as part of Kodak's Office Imaging Group, and Kodak's other COM-based solutions were still being made and marketed then as well.
End
However, those early 1990s saw computer output to laser disc becoming a replacement technology. Sales of COM units went into a steep decline. Nonetheless, Kodak Komstar systems were still in operation at some sites into the late 1990s.
References
External links
"Kodak Office Imaging" – Rick Swenton's account of how the Komstar worked interally and how maintenance was done for it
"Creating the Kodak KOMSTAR Interface Program" – Rocket Software's instructions for Mobius z/OS v10.1
Kodak
Computer-related introductions in 1977
Computer peripherals
Archival technology | Kodak Komstar | [
"Technology"
] | 1,201 | [
"Computer peripherals",
"Components"
] |
78,384,881 | https://en.wikipedia.org/wiki/Bentranil | Bentranil is a postemergent herbicide used to control annual weeds in cereal crops, maize, and rice. of bentranil was used in the US in 1974. Bentranil has excellent selectivity on germinaceous crops, potatoes and soybeans, but was never commercialised due to the high doses needed to control broadleaf weeds.
Bentranil is synthesised from 2-iodobenzoic acid and benzonitrile.
Medical potential
Bentranil derivates show promise as highly selective Cytochrome P450 inhibitors, which is desirable to prevent and treat cancer, as P450 is highly expressed in tumours and is implicated to drug resistance.
Derivatives
Fluorobentranil (bentranil that has undergone fluorine substitution) showed good broad-leaf activity and selectivity on rice, cereals and maize. The 5-fluoro derivative showed triple the standard herbicidal activity. The fluorine's electronegativity strengthens binding to enzymes.
References
Herbicides
Benzoxazines
Lactones | Bentranil | [
"Biology",
"Environmental_science"
] | 220 | [
"Herbicides",
"Biocides",
"Toxicology",
"Pesticides"
] |
78,384,896 | https://en.wikipedia.org/wiki/Ukrainian%20energy%20crisis | In 2024, Ukraine faced an energy infrastructure crisis unprecedented in its national history as a result of sustained Russian military attacks on its power generation facilities and transmission networks, in addition to disconnection from the Russian and Belarusian energy grid. The situation created significant challenges during the 2024 winter season, with the country's generating capacity severely compromised and facing widespread blackouts, leading to difficulties in heating Ukrainian households as well as further economic challenges to the nation. The crisis was referred to by energy and geopolitical experts as one of the most severe disruptions to a national power system in recent history.
Background
The first eight months of 2024 saw more than 400 missiles and drones targeting Ukraine's energy infrastructure, with particularly intensive attacks in March and August. The August 26 assault was especially severe, involving 127 Russian missiles and 109 Shahed drones. While high-voltage substations demonstrated resilience with many being quickly repaired, the attacks significantly reduced the country's power generation capacity from the required 18 gigawatts (GW) to approximately 12-13 GW.
In addition, the Russian occupation of the Zaporizhzhia nuclear power plant alone removed six gigawatts of generating capacity from Ukraine's grid. Approximately 70% of the country's thermal generation amount was either damaged or under occupation by May 2024.
Crisis
As a result of the constant Russian attacks and takeovers of critical Ukrainian facilities, roughly half of all high-voltage substations sustained damage, along with extensive portions of the distribution network. The heating network faced comparably severe impacts, with eighteen major combined heat and power plants and over 800 boiler houses rendered inoperable. The financial toll was enormous, with damage to the electric power sector alone exceeding US$11.4 billion by mid-2024. Experts estimated that restoration costs would approach $30 billion.
The International Energy Agency estimated that 2024 winter peak demand would reach 18.5 GW, marking a dramatic increase from summer 2024's 12 GW requirement. Even with many nuclear units returning to service combined with anticipated imports of 1.7 GW from the European Union, analysts predicted a potential supply shortfall of 6 GW— equivalent to Denmark's entire average peak demand. This deficit threatened to extend the duration of rolling blackouts that had already become part of daily life in the summer, potentially disrupting essential services including centralized water supply. Urban centers were considered to be most vulnerable to energy deficits due to holding about 70% of Ukraine's population, and due to the necessity of power for high-rise buildings to maintain heating, elevator function, and running water.
The August 26 Russian assault caused the energy crisis to reach an apex at the time, leaving about eight million Ukrainian households without power and triggering the first unscheduled blackout in Kyiv since November 2022.
In September 2024, CEO of Ukrainian state energy company Ukrenergo Volodymyr Kudrytskyi was dismissed by the Ministry of Energy, which in turn resulted in two Ukrenergo Supervisory Board members' resignations.
Matthias Schmale, the UN's resident and humanitarian coordinator in Ukraine, stated in mid-November 2024 that Russian forces had destroyed approximately 65% of Ukraine's energy production capacity, creating what he estimated would likely be the most difficult winter period of conflict so far.
Following extensive Russian airstrikes on 17 November, several districts in Odesa Oblast, including Bolhrad and Podilsk, suffered from power outages in their critical infrastructure. Later, emergency power cuts were planned to be instated across all of Ukraine on November 18 from 6 am to 10 pm, with restrictions on energy consumption issued in tandem.
Impact
The crisis fundamentally transformed energy consumption patterns across Ukraine. Industrial power usage plummeted by 50%, while residential consumption declined by 20%, primarily due to population displacement. Despite this reduction in household usage, it became the largest share of energy demand. Summer 2024 reached 2.3 GW below the 12 GW peak demand. Severe power shortages occurred throughout Summer 2024 as a result, with Kyiv experiencing several blackouts lasting up to 16 hours in July.
Analysts warned of a potential humanitarian crisis caused by the energy crisis and its impacts, potentially forcing population movements within Ukraine and across borders as certain areas became uninhabitable due to heating limitations.
Economic
Ukrenergo, Ukraine's national power grid operator, faced a potential technical default by November 2024 due to the energy crisis. Corporate governance issues complicated efforts to secure international investment and implement financial solutions towards upholding the electrical grid. Ukraine accumulated substantial debt amid the conflict, with the Ukrainian Cabinet of Ministers' restructuring of the national debt resulting in delayed government bond payments. This in turn negatively impacted several state-owned companies due to their inability to pay off their bonds. Ukrenergo was left unable to pay off its bonds in early November 2024 necessary to prevent technical default. This, in addition to the dismissal of its CEO and subsequent resignation of two Supervisory Board members, made investments towards the ailing energy sector less attractive to potential investors and international allies.
Electrical utilities further struggled with revenue losses from reduced economic activity caused by the war, while facing additional costs from infrastructure repairs and debris removal. As a result, Ukrainian energy companies accumulated substantial debt, and government subsidies for heating costs placed severe strain on its fiscal resources.
Education
The energy crisis posed significant challenges to the Ukrainian education sector, as schools required substantial infrastructure upgrades to maintain operations during power outages. The demand for increasingly low-in-supply battery systems and solar panels significantly increased, particularly due to the impossibility of conducting online education during blackouts.
Heating
Several geopolitical analysts noted that the most substantial impacts of the energy crisis could come during the winter of 2024 due to the damaged energy infrastructure's inability to fully heat Ukrainian households. Analysts stated that while Summer 2024's warm weather and extended daylight hours partially masked the full extent of its infrastructure damage, the approaching winter— with average temperatures ranging from -4.8°C to 2°C while reaching as low as -20°C between December and March— threatened to starkly expose the system's vulnerabilities.
The International Energy Agency projected that heating capabilities would be worst impacted by regions near the conflict's front lines. Kharkiv Oblast lost several major heat-generating facilities, including the Kharkiv TEC-5 plant and the Zmiivska thermal power plant in March 2024 attacks. Similar challenges faced other war-impacted oblasts including Donetsk, Zaporizhzhia, Sumy, Chernihiv, and Mykolaiv. Even Kyiv, where 98% of residents relied on district heating, faced significant projected risks despite its three large and operational CHP plants.
It also estimated that the winter would increase household heating requirements by 25%, necessitating an additional 1.5 billion cubic meters of natural gas. The anticipated cessation of Russian gas transit through Ukraine in January 2025 further complicated the situation, eliminating possibilities for virtual gas reverse flows from the European Union and potentially increasing procurement costs.
International impact
Baltic States
The planned decoupling of Baltic states' electricity systems from Russia and Belarus on February 7, 2025 in conjunction with Ukraine's energy constraints and limited shipment of energy supplies resulted in potential risks to their regional energy security. While Baltic transmission system operators had long prepared for independent operation, the temporary reliance on a lone synchronous interconnection with Poland until 2030 introduced additional vulnerabilities to the synchronous grid of Continental Europe.
Moldova
The expected cessation of Russian gas transit through Ukraine threatened to disrupt Moldova's energy supply arrangements, especially regarding the Transnistria region's gas supply and its electricity generation for the whole of the nation. This situation required approximately 600 to 650 megawatts of interconnection capacity with Romania, exceeding current allocations and potentially threatening its regional stability.
Southern Europe
Market dynamics also faced potential disruption due to the limiting of Russian gas and oil transit via Ukraine. Southeast Europe was considered to be particularly vulnerable, where electricity prices remained elevated compared to pre-war levels due to the region's dependence on natural gas and having "tight gas markets [that] have combined with congested energy corridors, warm weather and low hydropower generation, resulting in notable price disparities with the rest of Europe".
Responses
Ukraine's energy sector underwent a radical transformation focusing on strategic energy resilience and redundancy in order to work around impacted sections of the energy grid. This included a shift toward decentralized power generation, with nearly 1,500 megawatts of consumer-installed solar power becoming operational by early 2024. Authorities implemented various protective measures, including the installation of emergency power systems for critical facilities, development of emergency response protocols, and the implementation of rolling blackouts to manage supply shortages.
Several Ukrainian cities implemented various contingency measures to maintain essential services during potential blackouts. Major metropolitan areas including Kyiv, Kharkiv, Odesa, and Zhytomyr developed emergency power systems for critical infrastructure, focusing on maintaining water supply, heating, and sanitation services. Healthcare facilities installed solar power systems and power generators into their electrical systems to allow for redundancy in case of power outages.
International
During the conflict, allies to Ukraine provided approximately US$2 billion in technical assistance to Ukraine's energy sector, with Ukrenergo receiving more than $1.5 billion of these funds. However, governance issues and market instability significantly exacerbated by the war hindered the effective utilization of this support towards rebuilding energy infrastructure and relieving energy constraints.
Europe
Ukraine began integration with the continental European grid. This connection provided access to up to 1.7 gigawatts of import capacity and emergency support capabilities following Ukraine's disconnection from the Russian and Belarusian power system. The integration proved especially important given the severe impact on Ukraine's domestic heating infrastructure, which had previously served over one-third of households through district heating networks, predominantly fueled by natural gas.
United Nations
United Nations officials condemned Russian targeting of civilian energy infrastructure as a direct violation of international humanitarian law which threatened to create a humanitarian crisis. The UN noted that residents of high-rise urban buildings, disabled individuals, elderly citizens, and the 3.6 million internally displaced people within Ukraine were especially vulnerable during extended power outages in sub-zero conditions. UN officials urged that European nations and the United States continue their current humanitarian assistance to prevent the worsening of healthcare failure, civilian casualties, and psychological trauma caused by Russian destruction of energy infrastructure and its impacts.
See also
EU natural gas price cap
Lukoil oil transit dispute
Moldovan energy crisis
References
Energy crises
2024 in Ukraine
Energy in Ukraine
Economic history of Ukraine
Events affected by the Russian invasion of Ukraine
Energy policy
2024 in economic history
Attacks on electrical infrastructure in Ukraine
Infrastructure in Ukraine | Ukrainian energy crisis | [
"Environmental_science"
] | 2,221 | [
"Environmental social science",
"Energy policy"
] |
78,385,053 | https://en.wikipedia.org/wiki/Keller%27s%20reagent%20%28metallurgy%29 | In metallurgy, Keller's reagent is a mixture of nitric acid, hydrochloric acid, and hydrofluoric acid, used to etch aluminum alloys to reveal their grain boundaries and orientations. It is also sometimes called Dix–Keller reagent, after E. H. Dix, Jr., and Fred Keller of the Aluminum Corporation of America, who pioneered the use of this technique in the late 1920s and early 1930s.
Safety
Keller's reagent contains oxidizing nitric acid and toxic hydrofluoric acid. The reagent and its fumes may be lethal via contact, inhalation of its fumes, etc. Hydrogen produced on contact with some metals may pose a fire hazard.
See also
Aqua regia
References
Metallurgy
Chemical mixtures | Keller's reagent (metallurgy) | [
"Chemistry",
"Materials_science",
"Engineering"
] | 169 | [
"Metallurgy",
"Chemical mixtures",
"Materials science",
"nan"
] |
78,385,062 | https://en.wikipedia.org/wiki/Keller%27s%20reagent%20%28organic%29 | In organic chemistry, Keller's reagent is a mixture of anhydrous (glacial) acetic acid, concentrated sulfuric acid, and small amounts of ferric chloride, used to detect alkaloids. Keller's reagent can also be used to detect other kinds of alkaloids via reactions in which it produces products with a wide range of colors. Cohn describes its use to detect the principal components of digitalis (note that they may not be alkaloids). The reaction with this reagent is also known as the Keller–Kiliani reaction, after C. C. Keller and H. Kiliani, who both used it to study digitalis in the late 19th century. It can be used for digitoxin's quantitative analysis.Another method of visualizing the Keller-Kiliani reaction is to treat the test solution with ferric chloride-containing glacial acetic acid, followed by the addition of concentrated sulfuric acid, which sinks to the bottom (like in the brown ring test for nitrates). A brown ring in the interface indicates the presence of cardenolides.
List of color changes with various compounds
Digoxin: olive-brown without red traces
Digitoxin: green, then blue
Digoxigenin: greenish-yellow
Vindolicine: bright blue
Uleine: yellow-brown
Hunteria eburnea alkaloid J (C39H46N4O2): pale red, later blue violet
See also
Dische test
Baljet reaction
References
Chemical mixtures
Organic reactions | Keller's reagent (organic) | [
"Chemistry"
] | 323 | [
"Chemical mixtures",
"nan",
"Organic reactions"
] |
78,385,491 | https://en.wikipedia.org/wiki/Joslynn%20Lee | Joslynn Lee is an Native American biochemist and an assistant professor at Fort Lewis College in Durango, Colorado whose research focuses on computational biology and molecular modeling. She advocates for indigenous students and established major institutional changes by inspiring a deconstruction of offensive plaques that white-washed the history of violence and ethnocide toward Native students on the college's land.
Early life
Lee grew up in Farmington, New Mexico. She is Native American, identifying as Navajo, Laguna Pueblo, and Acoma Pueblo. When she was young, her grandmother would pick plants to make natural dyes which later inspired Lee to connect her native heritage with science.
Career
In 2014, Joslynn Lee received a Ph.D. in chemistry from Northeastern University and then worked briefly as a postdoctoral researcher at the University of Minnesota Medical School, during which she worked with faculty to analyze their sequencing data. In 2015, she took up a position as a data science educator at Cold Spring Harbor Laboratory. There, she trained undergraduates to incorporate computational biology and chemistry into their curricula, visiting institutions throughout the United States to train their faculty how to implement her curriculum. Later she joined the Howard Hughes Medical Institute in order to develop an undergraduate research for analyzing microbial communities.
In Fall 2019, Joslynn Lee became a chemistry professor at Fort Lewis College. In the same year, she launched the Monitoring Environmental Microbiome program which focused on the mining impacts on the San Juan Watershed, hoping to encourage Native American and underrepresented students to explore data science and scientific computing. Lee encourages the use of indigenous languages such as her own, Diné, in the classroom in order to create a safe space for other Native students. She identifies with the six percent of indigenous faculty employed at Fort Lewis, despite almost over half of students also having native ancestors. She also runs the Fort Lewis Equity Group that was launched in 2022 with a $25,000 grant.
Legacy and impact
Joslynn Lee is the first Native American to become a chemistry professor at Fort Lewis College. When she began her faculty position, Lee wrote letters to Fort Lewis College's president, Tom Stritikus, advocating for the removal of the historical markers on a clock tower at the center of campus. The markers were inscribed with inaccurate information on the history of the college's past as a previous Native American boarding school. In response to Lee's efforts, the school's administration held over a year of listening sessions before removing them on September 6th, 2021.
Publications
Bolyen, E.; Rideout, J.R.; Dillon, M.R.; Bokulich, N.A.; Abnet, C.; Al-Ghalith, G.A.; Alexander, H.; Alm, E.J.; Arumugam, M.; Asnicar, F.; et al. (2019) Reproducible, interactive, scalable and extensible microbiome data science using QIIME 2. doi:10.1038/s41587-019-0209-9. PMID 31341288 S2CID 198496880
Bolyen E, Rideout JR, Dillon MR, Bokulich NA, Abnet CC, Al-Ghalith GA, Alexander H, Alm EJ, Arumugam M, Asnicar F,; et al. (2019) Author Correction: Reproducible, interactive, scalable and extensible microbiome data science using QIIME 2. Nat Biotechnol. Erratum for: Nat Biotechnol. 2019 Aug;37(8):852-857. doi: 10.1038/s41587-019-0252-6. PMID: 31399723. S2CID 199519152
Lacher, S.E., Lee, J.S., Wang, X., Campbell, M.R., Bell, D.A., & Slattery, M. (2015). Beyond antioxidant genes in the ancient Nrf2 regulatory network. Free radical biology & medicine, 88 Pt B, 452-465 . doi:10.1016/j.freeradbiomed.2015.06.044. PMID 26163000 S2CID 13781789
Zhang, Y., Lee, J.K., Toso, E.A., Lee, J.S., Choi S.H., Slattery, M.G., Aihara, H., Kyba, M. (2016). DNA-binding sequence specificity of DUX4. Skelet Muscle 6(8). doi:10.1186/s13395-016-0080-z. PMID 26823969 S2CID 3514854
Parasuram, R., Lee, J. S., Yin, P., Somarowthu, S., Ondrechen, MJ. (2010) Functional Classification of Protein 3D Structures From Predicted Local Interaction Sites. Journal of Bioinformatics and Computational Biology. 8, SI1, 1-15. doi:10.1142/s0219720010005166. PMID 21155016 S2CID 20328014
Awards and recognition
Joslynn Lee was awarded the 2023 National Science Foundation Graduate Research Fellowship. Lee was also selected as a Kavli Frontiers in Science fellow, which provides career development for potential leaders in science.
References
Wikipedia Student Program
People from New Mexico
21st-century Native American scientists
Navajo scientists
21st-century Native American women
Women biochemists
Northeastern University alumni
Fort Lewis College faculty
Year of birth missing (living people)
Living people | Joslynn Lee | [
"Chemistry"
] | 1,208 | [
"Biochemists",
"Women biochemists"
] |
78,385,640 | https://en.wikipedia.org/wiki/Glyphosine | Glyphosine is a plant growth regulator used on sugar beet and sugarcane. It inhibits fiber production, causing the plant to divert more dry matter to sucrose storage. of glyphosine were used in the US in 1974. It was first registered in 1972, though now is considered largely obsolete. In other plants, e.g. maize, it causes chlorosis by inhibiting plasmid RNA synthesis. It can be synthesized from chloroacetic acid and N,N-bis(phosphonomethyl)amine. Metals form complexes with glyphosine.
Chemically, glyphosine is a tertiary amine, a glycine derivative and a phosphonic acid.
It has been manufactured by CCA Biochemical and Monsanto, and sold under the "Polaris" trademark.
References
Links
Herbicides
Acetic acids
Tertiary amines
Phosphonic acids
Plant growth regulators | Glyphosine | [
"Biology"
] | 197 | [
"Herbicides",
"Biocides"
] |
78,385,764 | https://en.wikipedia.org/wiki/Metapenaeopsis%20barbata | Metapenaeopsis barbata, commonly known as the whiskered velvet shrimp, is a species of prawn in the family Penaeidae. It is benthic, living in the depth range of 20–70 m. M. barbata grows up to 108 mm in length.
Distribution
Metapenaeopsis barbata is found in the Indo-west Pacific, from Japan through to Indonesia.
Anatomy
Metapenaeopsis barbata can be differentiated from similar species through its anatomical features. Its stridulating organ is strongly upcurved with between 18 and 23 ridges, and it has a large pterygostomial spine. It usually has 6–7 rostral teeth.
Mating
Specimens of M. barbata have been recorded to lay between 2,600 and 26,400 eggs during season.
References
Biota of Asia
Penaeidae
Crustaceans described in 1891 | Metapenaeopsis barbata | [
"Biology"
] | 186 | [
"Biota of Asia",
"Biota by continent"
] |
78,386,092 | https://en.wikipedia.org/wiki/Baljet%20reaction | The Baljet reaction is a qualitative and quantitative method of analysis published by Henri Baljet in 1918. This chemical reaction is used for the detection and colorimetric determination of cardenolides. To the sample, an aqueous hydroxide solution and an ethanolic picric acid solution is combined and added, with a positive test turning orange or red. The mechanism involves cardenolides 1 reacting in alkaline solution with picric acid 2 to form stabilized Meisenheimer complexes, as shown with the resonance form 3a to 3c:
See also
Keller's reagent (organic)
Dische test
References
Chemical reactions
Analytical chemistry | Baljet reaction | [
"Chemistry"
] | 133 | [
"Chemical reaction stubs",
"nan"
] |
78,389,788 | https://en.wikipedia.org/wiki/Eranga%20Weeraratne | Eranga Udesh Weeraratne is a Sri Lankan politician, engineer, and business executive who was appointed as a National List Member of Parliament in 2024 under the National People's Power (NPP) government. Subsequently he was appointed as deputy minister of Digital Economy.
Early life and education
Eranga is the eldest of three siblings. His sister, Chamindi, works in the real estate industry, and his brother, Suranga, serves as the Head of Finance and Administration at Omobio.
Weeraratne completed his primary education at Mahinda College and secondary education at Mahanama College. In 1990, he achieved 7 Distinctions and 1 Credit in the General Certificate of Education Ordinary Level (G.C.E. O/L) examination. Subsequently, in 1993, he obtained 2 A-grades and 2 B-grades in Physical Science at the General Certificate of Education Advanced Level (G.C.E. A/L).
In 2000, he graduated from the University of Moratuwa with a Bachelor's degree in Computer Science and Engineering.
Career
After graduating with a degree in Computer Science and Engineering, Weeraratne joined Infotechs Limited as an e-Business engineer during the early growth of internet technologies. He spearheaded the development of *OmniBIS*, the first Sri Lankan portal offering comprehensive digital collaboration tools. These innovative services included free email, online calendar, instant messaging, file storage, and personal organization—predating similar platforms like Gmail and Dropbox. A distinctive feature of OmniBIS was its capability to send and receive emails via SMS.
Subsequently, he became a founding member of WaveNET, a software development company specializing in telecom-based products and services. Initially launched with just three members, WaveNET has since expanded to a robust team of over 120 professionals. Weeraratne served as the CTO at WaveNET from 2003 to 2010.
In 2012, he assumed dual roles as CEO and CTO of Omobio Pvt. Ltd. Under his leadership, the Omobio team has been committed to creating innovative solutions with a positive global impact. The company has garnered numerous prestigious accolades, including National Best Quality ICT Awards for the Dialog Self-Care Application, Customer-Care Application, and TEAM – SMS Box platform solutions. Omobio has successfully served more than twenty telecom operators and service providers across twenty countries.
Weeraratne's strategic vision has positioned Omobio as a global leader in technological innovation, particularly in artificial intelligence (AI), machine learning (ML), and Internet of Things (IoT) solutions. The company has established international offices and continues to pursue expansion into Europe, Africa, and the Americas.
From 2010 to 2013, he concurrently held the position of CTO at Telfinity Systems (Pvt) Ltd.
Beyond his role at Omobio, Weeraratne has diversified his professional portfolio by assuming leadership positions in various organisations:
Chairman/Director at eimSky (Pvt) Ltd
Director at Textware (Pvt) Ltd
Chairman at Matrix Plantations
Chairman/Director at Spiceyaya (Pvt) Ltd
Chairman/Director at Spice Fortress (Pvt) Ltd
Director at E-Lottery Solutions (Pvt) Ltd
Political career
In 2019, Eranga entered active politics through the National Intellectuals Organisation (NIO), an organization of which he is a founding member. NIO is affiliated with the NPP party.
Weeraratne was appointed to the 17th Parliament of Sri Lanka as part of the NPP's National List in 2024. His selection reflects the party's emphasis on including experienced professionals and innovative leaders to guide policy and national development.
His appointment was received postively by the IT industry in Sri Lanka.
Personal life
Eranga is married to Prabhashini Herath, and they have two children.
Controversies
In 2012, social media posts and a gossip article alleged that Eranga Weeraratne was involved in a legal controversy regarding the theft of a laptop belonging to the late Professor Gihan Wikramanayake, then Director of the University of Colombo’s Computer Studies Institute (UCSC). The claims also suggested that 74 CDs and DVDs, including content alleged to be pornographic, were recovered from Weeraratne's residence during a police investigation and that a case was filed in the Fort Magistrate’s Court.
In December 2024, a detailed investigation by the fact-checking organization Fact Crescendo Sri Lanka concluded that these allegations were entirely fabricated. The findings revealed:
No official records or mainstream media reports exist to substantiate the claims.
The University of Colombo Computer Studies Institute confirmed that no such theft occurred, nor were any police complaints filed regarding the alleged incident.
Dr. D.A.S. Athukorala, the current director of the institute, stated that neither Weeraratne nor the co-accused were staff members of the institute.
The allegations appear to have originated from an old gossip article published in 2012, and no credible evidence supports them.
Fact Crescendo further suggested that the false narrative might have been a smear campaign by rival businesses in the software industry. The Digital Deputy Minister’s office also denied the allegations, confirming that Weeraratne was not affiliated with the University of Colombo at the time.
See also
National People's Power
Parliament of Sri Lanka
References
Members of the 17th Parliament of Sri Lanka
National People's Power politicians
Sri Lankan engineers
Sri Lankan business executives
Alumni of the University of Moratuwa
People in information technology
1974 births
Living people | Eranga Weeraratne | [
"Technology"
] | 1,128 | [
"People in information technology",
"Information technology"
] |
78,389,810 | https://en.wikipedia.org/wiki/96P%20sungrazer%20family | The 96P sungrazer family is a small group of sungrazing comets, originating from the comet 96P/Machholz. It is only observed by LASCO corongraphs aboard SOHO (Solar and Heliospheric Observatory) probe. It contains three subgroups: Marsden, Kracht and Kracht II.
96P type is the rarest among all objects recorded by SOHO: just 3% of all belong to this group.
The 5000th comet observed by this probe belongs to the Marsden group, and was discovered on 25 March 2024.
Source and discovery
It is suggested that this group comes from fragments detached from the Macholz comet about 800 to 1,200 years ago. The orbit is very similar to the parent body with slightly different gravitational contacts with Jupiter and lower perihelion distance as well as inclination.
The Marsden subgroup was discovered by British astronomer Brian G. Marsden and the same as Meyer group, it was announced on 18 February 2002. Kracht I and II were discovered by Rainer Kracht in 2002 after analysing orbits and finding similarities between a pair of comets.
Characteristics and frequency
These objects show up at intervals averaging around 6 years: their approximate orbital period. They are often observed in clusters of two or more objects, showing up within few days after each other. Peak brightness typically occurs a few hours after perihelion, and the apparent magnitude typically ranges from 7 to 8 magnitude, although the brightest ones can reach apparent magnitude 5.
During passage near the Sun, fragmentation takes place, creating smaller objects. The 96P complex will likely become extinct in the near future.
The size range is not well known; they are probably larger than Kreutz group comets, which are usually a few tens of meters wide.
References
Astronomy
Cometary objects | 96P sungrazer family | [
"Astronomy"
] | 366 | [
"Cometary objects",
"Astronomical objects",
"nan"
] |
78,389,911 | https://en.wikipedia.org/wiki/NGC%201285 | NGC1285 is a barred spiral galaxy in the constellation of Eridanus. Its velocity with respect to the cosmic microwave background is 5081 ± 12km/s, which corresponds to a Hubble distance of . However, three non-redshift measurements give a distance of . It was discovered by Heinrich Louis d'Arrest on 28 October 1865.
Supernovae
Three supernovae have been observed in NGC 1285:
SN 2004F (typeIIn-pec, mag. 17.8) was discovered by the Lick Observatory Supernova Survey on 16 January 2004.
SN 2013el (typeIb-pec, mag. 15.5) was discovered by Stu Parker on 11 July 2013.
SN 2017fvf (typeIIP, mag. 17.81) was discovered by the Gaia Photometric Science Alerts programme on 30 July 2017.
See also
List of NGC objects (1001–2000)
References
External links
1285
012259
-01-09-026
03154-0728
Eridanus (constellation)
18651028
Discoveries by Heinrich Louis d'Arrest
barred spiral galaxies | NGC 1285 | [
"Astronomy"
] | 234 | [
"Eridanus (constellation)",
"Constellations"
] |
78,395,415 | https://en.wikipedia.org/wiki/Resonating%20device | A resonating device is a structure used by an animal that improves the quality of its vocalizations through amplifying the sound produced via acoustic resonance. The benefit of such an adaptation is that the call's volume increases while lessening the necessary energy expenditure otherwise required to make such a sound. The resulting sound may also radiate more efficiently throughout the environment.
The resonator may take the form of a hollow (a resonant space), a chamber (referred to as a resonating chamber), or an otherwise air-filled cavity (such as an air sac) which may be part of, or adjacent to, the animal's sound-producing organ, or it may be a structure entirely outside of the animal's body (part of the environment). Such structures use a similar principle to wind instruments, in that both utilize a resonator to amplify the soundwave that will ultimately be uttered.
Such structures are widespread throughout the animal kingdom, as sound production is important in the social lives of various animals. Arthropods developed their resonating devices from various parts of their anatomy; bony fish often utilize their swim bladders as a resonating chamber; various tetrapods developed resonating devices in parts of their respiratory tract, and evidence suggests that dinosaurs possessed them as well. Vocalizations produced through zoological resonating devices act as mating calls, territorial calls, and other communication calls.
In arthropods
Insects
Cicadas produce songs as part of their courtship display; the males of a number of species possess an abdomen that is largely hollow. The sound producing organ, the tymbals, are connected to the abdomen, and as a consequence their calls are amplified significantly; cicadas have been recorded to emit sounds of around 100 decibels, which is enough to cause hearing loss after 15 minutes. A large australian species, Cyclochila australasiae, produces sounds of up to 120 decibels at close range. In contrast, the basal hairy cicadas (Tettigarcta) do not emit an audible, airborne sound; like related leafhoppers, they instead transmit their vibrations through their substrate, turning the plants they perch upon into resonators.
A species of aquatic bug, Micronecta scholtzi, has been recorded to produce sounds of 105 dB, the "highest ratio dB/body size". This sound is produced via stridulation of the paramere (genital appendage) on an abdominal ridge, and may be amplified by reflections and refractions within the layer of trapped air the bug uses as an air supply, though the use of the air bubble as such has not been proven.
Tree crickets (specifically, Oecanthus henryi) were found to create baffles by selecting appropriately sized leaves, then chewing a hole near the centre that was about the size of their wings. By calling from inside of these baffles, they were able to prevent acoustic short-circuiting and effectively increasing the loudness of its calls.
In osteichthyans
Bony fish possess an air-filled organ called the swim bladder that is primarily used to regulate buoyancy. However, a number of species have adapted their swimbladders to be a part of a sound-producing organ. The sound-producing apparatus consists of fast-contracting striated muscles that vibrate the swim bladder, either entirely attached to the swimbladder or also attaching to adjacent structures like the vertebral column or occipital bones.
The drums or croakers, family Sciaenidae, are named after the sounds that they produce through their specialized vocal apparati consisting of their swim bladder, which is surrounded by special sonic muscle fibers that vibrate against the resonant swim bladder.
A number of catfish, including those in the families doradidae and pimelodidae, such as Platydoras and Pimelodus, also possess specialized drumming muscles attached to their swimbladders in order to produce sound.
The minute cyprinids of the genus Danionella, such as Danionella cerebrum, are able to create sounds in excess of 140 decibels through a mechanism that "shoots" a drumming cartilage at the swimbladder at over 2000 g. This all occurs in a fish measuring up to in length, being one of the smallest extant vertebrates.
Other families of fish which have sound-generating mechanisms involving the swim bladder include:
Mormyrids
Characids
Batrachoidids
Triglids
Gadids
In amphibians
Frogs possess vocal sacs which serve to enhance their nuptial calls. To call, the frog closes its mouth, then expels air from its lungs, through its larynx, and into the vocal sac; the larynx's vibration causes the vocal sac to resonate. Additionally, some frogs may call from inside structures that further amplify their calls; Metaphrynella sundana call from inside tree hollows with water pooling at the bottom, tuning their own calls to the resonant frequency of their specific tree hollow. Mientien tree frogs (Kurixalus idiootocus) residing in urban areas utilize storm drains to improve their calls; frogs calling within the drains called louder and for longer periods.
In amniotes
Mammals
Primates
The larynx is the primary vocal organ of mammals. In humans, it acts as a resonator only for high frequencies, due to its small volume; the pharynx, oral-, and nasal cavities, descending in order, are the most important resonators in humans.
Several non-human primates are adapted to producing loud calls, and they often rely on resonance chambers to produce it. The howler monkeys possess extralaryngeal airsacs along with a pneumatized (hollow) hyoid bone; it is suggested that the hollow hyoid acts as a resonating chamber, allowing the howler monkey to produce its namesake call. Gibbons are also well known for their loud territorial calls; the siamang has a particularly well developed gular sac that acts as a resonating chamber. Male orangutans also use their throat pouches for the purpose of enhancing their calls.
Male gorillas' airways have air sacs that penetrate into the soft tissue of the chest. These airsacs amplify the sound produced by his percussive chest-beating.
Laurasiatheres
Horseshoe bats (of the family Rhinolophidae) are a bat genus that possess air pouches, or chambers, around their larynx which act as Helmholtz resonators. The male hammerhead bat has an extremely large larynx that extends through most of his thoracic cavity, displacing his other internal organs. A pharyngeal air sac connects to a large sinus in the bat's snout; these structures act as resonating chambers to further amplify the bat's voice. So specialized are these structures that scientists Herbert Lang and James Chapin remarked; "In no other mammal is everything so entirely subordinated to the organs of voice".
Pinnipeds have been noted to employ this structure; the expanded nasal chambers of elephant and hooded seals act as resonant spaces that enhance their calls. The expanded laryngeal lumen of California sea lions, the pharyngeal pouch of walrus, and the tracheal sacs of various phocids may also function in a similar manner.
Mysticetes, such as the blue whale, use their greatly expanded larynx as a resonant cavity. Even in juveniles, the larynx is bigger than either one of the whale's lungs. This organ, along with the nasal passages, act as resonant spaces that produce the signature drawn-out calls of the baleen whales.
Sauropsida
Crocodylians
The ghara of the indian gharial is a specialized organ that acts as a resonating chamber; as a result, the call of a mature male can be heard up to away.
Lambeosaurines
The crests of a number of lambeosaurine dinosaurs have been hypothesized to act as resonating chambers; reconstructed upper airways, specifically, the nasal passsages of Parasaurolophus, Lambeosaurus, Hypacrosaurus and Corythosaurus have been examined, and they were concluded to be able to enhance the vocalizations in life, and the different cranial crest shapes would have distinguished the sounds produced between genera.
Birds
The avian syrinx is the primary vocal organ in most birds, with the trachea being the primary resonator in the system. In some birds, the trachea is grossly elongated, coiling or looping within the thorax; the trumpet manucode's trachea is 20 times longer than is predicted for birds of a comparable size. This condition of tracheal elongation (TE) is known in several orders of birds, and it seems to have been evolved independently a number of times. W. T. Fitch hypothesizes that the function of such elongated trachea in birds may be to "exaggerate its apparent [body] size", through the lowering of the frequency (Hz) of its calls; larger individuals are preferentially selected as mates, and thus a "deeper" voice is selected for. Additionally, lower frequency calls travel further, attracting mates from a wider area.
Additionally, the air sac system, which is part of the respiratory system in birds, may be an important resonator in certain birds, as is the inflated crop of columbiform pigeons and doves.
References
External Links
Fossils Reveal When Animals Started Making Noise, Michael B. Habib for Scientific American
Organs (anatomy)
Ethology
Zoology
Paleontology | Resonating device | [
"Biology"
] | 2,044 | [
"Behavioural sciences",
"Ethology",
"Behavior",
"Zoology"
] |
78,395,532 | https://en.wikipedia.org/wiki/I-PRO | i-PRO is a company established in Japan in 2019, originating from a division of Panasonic. The company manufactures video protection cameras with advanced AI video data analytics, as well as specialized camera modules integrated into medical devices, catering to security surveillance, public safety, medical imaging, and industrial applications.
History
Panasonic had been in the semiconductor industry since 1957, with their semiconductor technologies used in various applications, including video surveillance cameras. IP network camera business started in 2001.
In 2019, Panasonic sold its security systems (security camera) businesses. Panasonic i-PRO Sensing Solutions Co., Ltd. was established as an independent entity, spun off from Panasonic’s Security Systems Business Division, with co-investment from Polaris Capital Group Co., Ltd. Since 2019, it has been providing surveillance camera systems. Since July 2020, the company has been offering network cameras with artificial intelligence (AI) capabilities directly integrated into the devices. In the spring of 2021, i-PRO took another step by including AI by default in its mid-range camera lineup.
The company established itself in Amsterdam, Netherlands in 2021 for the European market and in Houston for the US market. R&D facilities are located in Fukuoka.
Starting in 2023, it is developing products in the industrial sector to reduce the management workload of factory production lines, using artificial intelligence. In the same year, it signed the United Nations Global Compact.
Products
Its technology uses artificial intelligence to analyze metadata captured on video in real time. When a person or vehicle is detected on the screen captured by the camera, it is surrounded by a blue frame. If the object enters a restricted area, the color of the frame instantly changes to red and an alarm sounds. To simplify the management of its cameras' AI capabilities, i-PRO also launched Multi-AI software (Active Guard), a plug-in that allows for the supervision of data analysis from multiple cameras within a video management system.
References
External links
Official website
Companies established in 2019
Japanese companies established in 2019
Security companies
Electronics companies
Video surveillance companies | I-PRO | [
"Engineering"
] | 421 | [
"Electronics companies",
"Engineering companies"
] |
78,396,381 | https://en.wikipedia.org/wiki/Gennaro%20Maria%20D%27Afflitto | Gennaro Maria D'Afflitto (1618 – 1673) was an Italian Dominican friar and military engineer who worked under Philip IV and Charles II of Spain.
Biography
Gennaro Maria D'Afflitto was born into a noble family in Naples in 1618. On 16 September 1633, he entered the Dominican convent of Santa Maria della Sanità, Naples. He received a good scientific and humanistic education, and developed a keen interest in mathematics. In 1647 he met Don John Joseph of Austria, who had been sent to Naples to quell the rebellion of Masaniello. He followed him in the campaign to recapture Orbetello and Porto Longone (1650) and later served as military engineer in the Spanish Army in Catalonia, Portugal and the Southern Netherlands. In 1663 the Supreme Council of War appointed him as professor of mathematics in the Real Academia de Matemáticas, Artillería y Fortificación of Madrid. He was in charge of the chair until 1665. In the following years, he came under the service of Ferdinando II of Tuscany again as a teacher of mathematics and military engineer. At the end of 1667 he became an advisor to the Republic of Genoa on engineering matters, and worked on the fortifications of Savona and Vado Ligure. D'Afflitto is also credited with fortification works in Cuneo and Nizza Marittima on behalf of the House of Savoy. He died at Naples in 1673.
Works
D'Afflitto published at Madrid a treatise on fortifications in two volumes, De Munitione et Fortificatione, Libri duo. The first volume is dedicated to Don John Joseph of Austria. Abstracts of this work were published at Florence in 1665, by Captain Giovanni Battista Sergiuliani, and in 1667 by Filippo Domenico Mazzenghi. Likewise, he is the author of Compendio de modernas fortificaciones (Compendium of Modern Fortifications), translated into Spanish in 1657 by Baltasar Siscara. D'Afflitto wrote also a treatise on fire and explosive weapons, De igne et ignivomis (Zaragoza, 1661). The work is divided into two parts: the first deals with the nature of fire and the different kinds of fuels; the second describes various types of explosives. He left in manuscript Terra seu quadripartites orbis, Compendio della Sfera universale, and a number of poems and miscellaneous tracts on philosophical and theological topics. Jonas Moore considered D'Afflitto, together with Francesco Tensini and Pietro Sardi, one of Italy's foremost experts on fortification.
Published works
De munitione et fortificatione (Matriti s. d.)
References
Bibliography
Italian engineer stubs
Italian engineers
Military engineering
Engineers from Naples
1618 births
1673 deaths | Gennaro Maria D'Afflitto | [
"Engineering"
] | 578 | [
"Construction",
"Military engineering"
] |
78,396,435 | https://en.wikipedia.org/wiki/Operation%3A%20Tango | Operation: Tango is a cooperative first-person video game, created by the Canadian studio Clever Plays. Two players take control of either an Agent or a Hacker and must work together to solve puzzles to bring down a hi-tech global menace.
Premise and gameplay
Announced in 2020, Operation: Tango is an asymmetrical co-operative game that puts the player in control of either Angel, a field operative, or Alistair, a top hacker, tasked with saving the world by investigating and locating a global cyber-criminal named Cypher.
Reception
Critical response
The Xbox Series X version of Operation: Tango received generally favorable reviews according to review aggregator Metacritic. Jerome Joffard of Jeuxvideo.com generally praised Operation: Tango for its unique and innovative gameplay, particularly the asymmetric cooperative experience where players assume the roles of Agent and Hacker. However, he criticized the game's repetitiveness and unclear objectives in later missions, which he felt could frustrate players. In their review of Operation: Tango, Zheng Yi of Geek Culture praised the futuristic world, comparing it with the cyberpunk aesthetic of Keiichi Matsuda's Hyper-Reality and the distinctive style of Robert Valley. Thomas Heath of TheGamer applauded the game for its engaging gameplay and globe-trotting setting, which he believes make it a thrilling co-op experience. He does however note that the game's relatively short length might leave some players wanting more.
Awards
Operation: Tango has won a number of awards since its release, including "Best Game Design Award Winner" at the Tokyo Game Show 2021 Sense of Wonder Night, "Best Multiplayer Game Winner" at the Gamescom 2021 Indie Arena Booth, and "Grand Winner PC Game - Multiplayer Game" at the NYX Game Awards 2021.
References
External links
Asymmetrical multiplayer video games
Cooperative video games
First-person video games
Puzzle video games
2021 video games
Indie games
Windows games
PlayStation 4 games
Xbox One games | Operation: Tango | [
"Physics"
] | 395 | [
"Asymmetrical multiplayer video games",
"Symmetry",
"Asymmetry"
] |
78,396,500 | https://en.wikipedia.org/wiki/Great%20Big%20Game%20Show | Great Big Game Show is an interactive, live-action game show where participants are cast as contestants, competing in teams. It combines elements of traditional game shows with interactive gameplay.
Concept and Gameplay
Great Big Game Show was designed by the team behind The escape game to simulate the experience of a televised game show, allowing participants to step onto a sound stage with lighting, music, and a live host. Each game session involves two teams competing in a series of rounds, with game play that changes in style and difficulty. Players may encounter a variety of challenges, including trivia questions, puzzle-solving, minute-to-win-it challenges, games of chance, and physical prop-based activities.
Locations and Expansion
The Great Big Game Show launched in July 2023 at Opry Mills Mall in Nashville, Tennessee. Due to growing popularity, a second location opened at Grandscape in The Colony, Texas, in November 2023. It has since expanded to additional locations, including the Mall of America in Bloomington, Minnesota; Fisherman's Wharf in San Francisco, California; and CityCentre in Houston, Texas.
External links
Official Website
References
Entertainment in the United States
Tourist attractions in Texas
Puzzle competitions
Play (activity)
Video game culture | Great Big Game Show | [
"Biology"
] | 248 | [
"Play (activity)",
"Behavior",
"Human behavior"
] |
78,396,540 | https://en.wikipedia.org/wiki/Tanguy%20Rivoal | Tanguy Rivoal (born 1972) is a French mathematician specializing in number theory and related fields. He is known for his work on transcendental numbers, special functions, and Diophantine approximation. He currently holds the position of Directeur de recherche (Research Director) at the Centre National de la Recherche Scientifique (CNRS) and is affiliated with the Université Grenoble Alpes.
Education
Rivoal obtained his Ph.D. from the Université de Caen Normandie in 2001 under the supervision of Francesco Amoroso. His dissertation was titled Propriétés diophantiennes de la fonction zêta de Riemann aux entiers impairs (Diophantine properties of the Riemann zeta function at odd integers).
Research
Rivoal's research focuses on several areas of mathematics, including Diophantine approximation, Padé approximation, arithmetic Gevrey series, values of the Gamma function, transcendental number theory, and E-function. His notable contributions include the proof that there is at least one irrational number among nine numbers ζ(5), ζ(7), ζ(9), ζ(11), ..., ζ(21), where ζ is the Riemann zeta function.
Together with Keith Ball, Rivoal proved that an infinite number of values of ζ at odd integers are linearly independent over , for which he was elected an Honorary Fellow of the Hardy-Ramanujan Society. They also proved that there exists an odd number j such that 1, ζ(3), and ζ(j) are linear independent over where 2 < j < 170, a specific case of the more general folklore conjecture stating that , ζ(3), ζ(5), ζ(7), ζ(9), ..., are algebraically independent over , which is a consequence of Grothendieck's period conjecture for mixed Tate motives.
See also
Apéry's constant
Apéry's theorem
Particular values of the Riemann zeta function
Wadim Zudilin
References
External links
Tanguy Rivoal's homepage
Tanguy Rivoal's list of published works
French mathematicians
Number theorists
Living people
Year of birth missing (living people) | Tanguy Rivoal | [
"Mathematics"
] | 468 | [
"Number theorists",
"Number theory"
] |
78,397,114 | https://en.wikipedia.org/wiki/Chunwei%20Song | Chunwei Song is a Chinese mathematician who specializes in combinatorics, graph theory, and intellectual history. He is a professor of mathematics at Peking University.
Education and career
Song received his Ph.D. in 2004 from the University of Pennsylvania, with the dissertation Combinatorial Theory of -Schröder Polynomials, Parking Functions and Trees under the supervision of Professor James Haglund.
Prior to joining Peking University, Song held visiting faculty positions at Boston College in Massachusetts and Tokyo Institute of Technology in Japan. From 2005 to 2006, he served as a visiting associate professor in the Department of Mathematical and Computing Science at the Tokyo Institute of Technology (now Science Tokyo). In 2010, he was a visiting associate professor at the University of Delaware.
Research contributions
Song is the author of Lattice Path Combinatorics and Special Counting Sequences: From an Enumerative Perspective, CRC Press, Boca Raton, ISBN 978-1032671758.
Coauthored with Chen Dayue () and Xu Zhongqin (), Song is a main editor of the tribute volume Ding Shisun and Chinese Mathematics (《丁石孙与中国数学》).
Song also has scholarly interests in Chinese and East Asian intellectual history. He is the author of Heroes Brought Buddhism to the East of the Sea: A Fully Annotated Translation of The Preface of Haedong Kosŭng Chŏn, published in Sino-Platonic Papers (Issue 183).
Academic talks
In 2014, Song gave a talk at Academia Sinica titled The Art of Lattice Path Combinatorics and Combinatorial Statistics.
In 2021, Song delivered an invited talk at the 14th International Congress on Mathematical Education (ICME 14) at its Thematic Afternoon activities.
In 2022, he gave a Plenary Address at the 11th National Forum on Mathematics Culture organized by the Chinese Mathematical Society.
Editorial boards
Song is on the editorial boards of Enumerative Combinatorics and Applications,
Advances and Applications in Discrete Mathematics,
Frontiers of Mathematics,
and several other academic journals.
Ph.D. students
By 2024, Song had supervised seven doctoral students in the field of mathematics at Peking University, including one (Dr. Yong Zhang, with the dissertation A Study on the Early History of Homotopy Theory: From Brouwer to Hurewicz) on mathematical history co-advised with Prof. Wu Guosheng .
Recognition and influences
Song was a Council Member of both the 12th and the 13th Councils of the Chinese Mathematical Society.
In 2023, Song became an elected delegate of the Beijing Municipal People's Congress.
As a scholar, he contributes opinion pieces to prominent media outlets such as Phoenix Weekly, Southern Metropolis Daily, and The Daily Pakistan. His writings engage diverse audiences across various countries, offering insightful and impactful perspectives on a wide range of themes.
References
Living people
20th-century Chinese mathematicians
20th-century American mathematicians
21st-century American mathematicians
Combinatorialists
Peking University
University of Pennsylvania
Year of birth missing (living people) | Chunwei Song | [
"Mathematics"
] | 605 | [
"Combinatorialists",
"Combinatorics"
] |
65,475,016 | https://en.wikipedia.org/wiki/Damoctocog%20alfa%20pegol | Damoctocog alfa pegol, sold under the brand name Jivi is a recombinant DNA-derived, Factor VIII concentrate used to treat hemophilia A.
The most common side effects include headache, cough, nausea, and fever.
Damoctocog alfa pegol was approved for medical use in the United States in August 2018, and in the European Union in November 2018.
Medical uses
In the United States damoctocog alfa pegol is indicated for use in previously treated people twelve years of age and older with hemophilia A (congenital Factor VIII deficiency) for on-demand treatment and control of bleeding episodes; perioperative management of bleeding; or routine prophylaxis to reduce the frequency of bleeding episodes.
In the European Union, damoctocog alfa pegol is indicated for the treatment and prophylaxis of bleeding in previously treated people twelve years of age and older with hemophilia A (congenital factor VIII deficiency).
References
External links
Antihemorrhagics
Recombinant proteins | Damoctocog alfa pegol | [
"Biology"
] | 220 | [
"Recombinant proteins",
"Biotechnology products"
] |
65,475,791 | https://en.wikipedia.org/wiki/Project%20Negin | Negin () is the tentative title of an upcoming class of warship designed by Iran, unveiled in November 2019. The design of the vessel resembles littoral combat ship (LCS) in the American terminology, though Iranians have identified it as a 'heavy destroyer'.
Design and construction
The vessels in the class are to displace between 5,000 and 7,000 tons, according to what Iranian officials told press in November 2019. In April 2020, Iran announced that the design phase has been concluded and the construction of the lead ship will begin shortly.
Analyses
The project is described as an attempt to improve blue-water capabilities of the Islamic Republic of Iran Navy, by Farzin Nadimi of The Washington Institute for Near East Policy. Military journalist David Axe is skeptical that Iran can build such a warship.
See also
List of naval ship classes of Iran
List of military equipment manufactured in Iran
References
Ship classes of the Islamic Republic of Iran Navy
Military projects | Project Negin | [
"Engineering"
] | 194 | [
"Military projects"
] |
63,939,762 | https://en.wikipedia.org/wiki/Phage-assisted%20continuous%20evolution | Phage-assisted continuous evolution (PACE) is a phage-based technique for the automated directed evolution of proteins. It relies on relating the desired activity of a target protein with the fitness of an infectious bacteriophage which carries the protein's corresponding gene. Proteins with greater desired activity hence confer greater infectivity to their carrier phage. More infectious phage propagate more effectively, selecting for advantageous mutations. Genetic variation is generated using error-prone polymerases on the phage vectors, and over time the protein accumulates beneficial mutations. This technique is notable for performing hundreds of rounds of selection with minimal human intervention.
Principle
The central component of PACE is a fixed-volume vessel known as the “lagoon”. The lagoon contains M13 bacteriophage vectors carrying the gene of interest (known as the selection plasmid, or SP), as well as host E. coli cells that allow the phage to replicate. The lagoon is constantly diluted via the addition and draining of liquid media containing E. coli cells. The liquid flow rate is set such that the dilution rate is faster than the rate of E. coli reproduction but slower than the rate of phage reproduction. Hence, a fresh supply of E. coli cells is constantly present in the lagoon, but phage can only be retained via sufficiently fast replication.
Phage replication requires E. coli infection, which, for M13 phage, relies on protein III (pIII). When using PACE, the phage vectors lack the gene to produce pIII. Instead, the production of pIII is tied with the activity of the protein of interest via a mechanism that varies per use case, oftentimes involves an extra plasmid containing the pIII-expressing gene III (gIII) known as the accessory plasmid, or AP. Notably, production of infectious phage scales with the production of pIII. Hence, the better the activity of the protein, the higher the rate of pIII production, and the more infectious phage are generated for that particular gene.
Using error-prone polymerases (encoded on the mutagenesis plasmid, or MP), genetic variation is introduced into the protein gene portion of the phage vectors. Due to the selective pressures applied by the constant draining of the lagoon, only phages that can replicate fast enough can be retained in the lagoon, so over time beneficial mutations accumulate in phage replicating in the lagoon. In this manner, rounds of evolution are continuously performed, allowing hundreds of rounds to elapse with little human intervention.
Applications
Polymerase promoter specificity
In the initial paper pioneering this technique, T7 RNA polymerases were evolved to recognize different promoters, such as the T3 or SP6 promoters. This was done by making the target promoter the sole promoter for gIII. Hence, mutant polymerases with greater specificity for the desired promoter caused greater pIII production. This resulted in polymerases with ~3-4 orders of magnitude greater activity for the target promoter than the original T3 promoter.
While this original PACE system only performed positive selection, a variant was developed that allowed for negative selection as well. This is done by linking undesired activity to the production of non-functional pIII, which decreases the amount of infectious phage made.
Protease substrate specificity
Proteases have been evolved to cut different peptides using PACE. In these systems, the desired protease cut site is used to link a T7 RNA polymerase and a T7 lysozyme. The T7 lysozyme prevents the T7 polymerase from transcribing gIII. When the peptide linker is cleaved, the T7 polymerase is activated, allowing for the transcription of the pIII gene. This method was used to create a TEV protease with a significantly different peptide substrate.
Orthogonal Aminoacyl-tRNA Synthetases
Using PACE, aminoacyl-tRNA synthetases (aaRSs) were evolved for noncanonical amino acids as well. Activity of an aaRS is linked to pIII production by the addition of a TAG stop codon in the middle of gIII. Synthetases that aminoacylate the TAG codon's suppressor tRNA prevents stop codon activity, allowing for production of functional pIII. Using this system, aaRSs were evolved that utilize non-canonical amino acids p-nitro-phenyalanine, iodophenylalanine, and Boc-lysine.
Protein-Protein Interactions
Protein-protein interactions have been evolved using PACE as well. Under this scheme, the target protein is fused with a DNA binding protein, which binds to a target sequence placed upstream of the gIII promoter. The protein undergoing evolution is fused with an RNA polymerase. The better the protein-protein interaction, the more transcription of pIII occurs, allowing the evolution of the protein-protein interaction under PACE conditions. This method was used to evolve Bacillus thuringiensis endotoxin variants that can overcome insect toxin resistance.
Base Editors
PACE was used to evolve APOBEC1 for greater soluble expression. APOBEC1 is a cytidine deaminase that has found use in base editors to catalyze the single nucleotide edit C-->T. In E. coli, APOBEC1 usually falls out of solution into the insoluble fraction. To evolve APOBEC1 for better soluble expression, the N-terminus of a T7 polymerase was fused to APOBEC1, with the remaining portion of the polymerase separately expressed. The T7 polymerase can only function when the N-terminus portion can bind to the rest of the polymerase. Since APOBEC1 must be properly folded for the N-terminus portion to be exposed properly, T7 polymerase activity is correlated to APOBEC1 folding. As follows, pIII transcription and production is linked with APOBEC1 soluble expression via the T7 polymerase. Using this approach, the soluble expression of APOBEC1 was increased by 4 fold with no change in function.
PACE was also used to create a more catalytically active deoxyadenosine deaminase. Deoxyadenosine deaminase is used in base editors to perform the single nucleotide edit A-->T. This was done by placing adenosine-containing stop codons in the gene for T7 polymerase. If the base editor is able to correct the error, functional T7 polymerase is produced, allowing production of pIII. Using this system, they evolved a deoxyadenosine deaminase with 590 fold activity compared to wild type.
References
Evolutionary biology | Phage-assisted continuous evolution | [
"Biology"
] | 1,393 | [
"Evolutionary biology"
] |
63,940,009 | https://en.wikipedia.org/wiki/Sacred%20groves%20of%20Biodiversity%20Park%2C%20Visakhapatnam | The sacred groves is a zone of Biodiversity Park, Visakhapatnam located in the premises of Rani Chandramani Devi Government Hospital. It has more than 100 sacred plant species, which are medicinal herbs with religious importance. Many sacred plants are becoming rare and endangered. Hence they are to be reared, protected, and conserved. The zone was inaugurated on February 5, 2017, by Kambhampati Hari Babu, a member of parliament from Visakhapatnam, Andhra Pradesh.
Sacred plant species of the park in general
More than 300 tree species mentioned in holy books (Bhagvad Gita, Ramayana, Mahabharata, Bible, Quran, Tripitaka, Zend-Avesta, Guru Granth Sahib) related to different religions (Hinduism, Christianity, Islam, Jainism, Buddhism,
and Sikhism) are reared in different zones of the Biodiversity Park. Many tree species are commonly seen in more than one religion. For example, fig (Ficus carica) is almost common to all religions. Date palm (Phoenix dactylifera), olive (Olea europaea), pomegranate (Punica granatum), cypress (Cupressus sempervirens) are common to Christians and Muslims. Neem (Azadirachta indica), sacred fig or peepal or bodhi (Ficus religiosa), sal (Shorea robusta), sandal wood (Santalum album), bilva (Aegle marmelos) are common to Hindus, Buddhists and Jains. Banyan (Ficus bengalensis) and sacred fig (Ficus religiosa) are common to Hinduism, Buddhism, Jainsism, Judaism and Christianity. The maidenhair tree (Ginkgo biloba) is viewed as a sacred tree in all religions of China, Korea and Japan.
Some of the notable sacred plant species of the park are: maidenhair tree (Ginkgo biloba), Christmas tree (Araucaria excelsa), peepal/sacred fig/aswaddha (Ficus religiosa), banyan/marri/vata (Ficus benghalensis), ashoka tree (Saraca asoca), date palm (Phoenix dactylifera), Indian cedar / devadar (Cedrus deodara), cypress (Cupressus sempervirens), olive (Olea europaea), neem (Azadirachta indica), mango (Mangifera indica), kadamba (Anthocephalus cadamba), sandal wood (Santalum album), sami or jammi (Prosopis cineraria), bel, bilva or maredu (Aegle marmelos), moduga/flame of the forest (Butea monosperma), holy cross / calabash tree (Crescentia cujete), Indian lotus or padmam (Nelumbo nucifera), basilicum / tulasi (Ocimum sanctum), and rudraksha (Elaeocarpus ganitrus).
Sacred plant categories of the Sacred Grove Zone
The Sacred Groves Zone of the Biodiversity Park contains more than 100 plants under five categories namely Ganesha vana, Nakshatra vana, Raasi vana, Saptarishi vana and Navagraha vana. The pictures are shown in the gallery. Some plants or trees are common to more than one vana or garden. For example, raavi / peepal / sacred fig (Ficus religiosa) is common to Ganesha vana, Raasi vana, Saptarishi vana and Nakshtra vana. Similarly sandra / chandra / kachu (Acacia catechu) is common to Nakshatra vana, Navagraha vana and Raasi vana. Samee / jemmi (Prosopis cineraria) / (Prosopis spicigera) is common to Ganesha vana, Nakshatra vana, Navagraha vana and Raasi vana. Bilva / maredu / bael (Aegle marmelos) is common to Ganesha vana, Nakshatra vana and Saptarishi vana.
Ganesha vana – Ganesha garden with 21 plants
This consists of 21 leaves (Aeakavimshathi patraha) of 21 plant species connected with the worship of Lord Ganesha.
This might also be the same as the Siddhivinayak Mandala Vaatika, where the garden is designed as per sacred geometry dedicated to SiddhiVinayak, another name for Lord Ganesha.
A Mandala Vaatika, simply put, is a garden that is structured like a Mandala (i.e. in a circular geometric designs). However, in Vedic times, these gardens were created as per very specific mathematical calculations, patterns and measurements. Each deity and planet has their own unique Mandala geometry. These gardens were treated as sacred groves where one could meditate and experience the vibrations of these deities.
So, in ancient India one could meditate in a Rudra Mandala Vaatika, a Durga Mandala Vaatika, a Murugan Mandala Vaatika, a Varamahalakshmi Mandala Vaatika or even a Saptarishi Mandala Vaatika dedicated to the 7 most revered sages.
Nakshatra vana - garden with plants for 27 stars
The nakshatra vana comprises plant species connected with the 27 stars or star constellations of Indian astrology.
Raasi vana - garden with plants for 12 zodiac signs
This comprises plant species connected with the 12 signs in the zodiac system.
Saptarishi vana - garden of plants for seven great Indian sages
This comprises plant species connected with seven great Indian sages or rishis.
Navagraha vana - garden with plants for nine planets
This comprises nine plant species connected with nine planets or celestial bodies.
Gallery
Some notable sacred plant species:
See also
Biodiversity Park, Visakhapatnam
Dolphin Nature Conservation Society
References
Sacred groves
Botanical gardens in India
Medicinal plants
Biodiversity Heritage Sites of India
2017 establishments in Andhra Pradesh | Sacred groves of Biodiversity Park, Visakhapatnam | [
"Biology"
] | 1,300 | [
"Biodiversity Heritage Sites of India",
"Biodiversity"
] |
63,940,168 | https://en.wikipedia.org/wiki/WASP-29 | WASP-29 is a binary star system away in the constellation of Phoenix. The primary star is a K-type main-sequence star. Its comoving companion, a red dwarf star, was discovered in 2021. The star system kinematically belongs to the thin disk of the Milky Way. The primary is an old star with small starspot activity and low x-ray flux.
Planetary system
The "hot Saturn" class planet WASP-29b was discovered around WASP-29 in 2010. The planet would have an equilibrium temperature of 960 K. The planetary atmosphere has abundant carbon monoxide but likely lacks methane and sodium, although the high and dense cloud deck of WASP-29b prevents high-quality spectroscopic measurements.
A study in 2018 revealed the stability of planetary orbits in the habitable zone of WASP-29 is significantly affected by the WASP-29b planet.
References
Phoenix (constellation)
Planetary systems with one confirmed planet
Binary stars
K-type main-sequence stars
M-type main-sequence stars
Planetary transit variables
J23513108-3954241
CD-40 15273
192
183537452
29 | WASP-29 | [
"Astronomy"
] | 230 | [
"Constellations",
"Phoenix (constellation)",
"Astronomy organizations",
"Wide Angle Search for Planets"
] |
63,940,707 | https://en.wikipedia.org/wiki/Avian%20sleep | In birds, sleep consists of "periods of eye closure interrupted by short periods of eye-opening." During the short periods of eye-opening, electroencephalographic (EEG) studies indicate that the birds are still sleeping; the voltage level in the brain is identical. Birds restore their arousal thresholds during sleep. During their short eye-open periods, sleeping birds can mobilize almost instantaneously when threatened by a predator. Avian species have been found to rely on flock size and height for predatory precautions. Between the eye-opening and group sleep, these precautions allow sleep to be beneficial and safe.
The amount of sleep necessary to function can vary by species. Pectoral sandpipers migrate from the Southern Hemisphere to the Arctic Circle, their mating ground (where they breed during daylight. Since the sandpipers are polygamous, they mate (or search for a mate) for the duration of daylight. Males do not require as much sleep during this time; some have been observed to give up 95 percent of their sleep time during the nineteen mating days. Most act similarly to humans when sleep-deprived, getting them into potentially life-threatening situations or slowing their migration speed.
Comparative anatomy of avian brain and nervous system
The typical avian nervous system is similar to that of mammals. The central nervous system includes the brain and spinal cord, and a peripheral nervous system consists of nerves and sensory organs. Key attributes have evolved compared to other species, especially vision; avian visual capabilities are believed to be more advanced than any other group of vertebrates. In addition to larger eyes, birds have larger-than-average optic lobes. With a larger, more intricate optic lobe, some bird species can view the ultraviolet (UV) spectrum (beyond the visual range of the human eye). This UV visual capability facilitates hunting, as seen in nighthawks. UV-sensitive cone opsin is typically responsible for avian ability to see UV, but some species have circumvented this; owls can see UV light, but lack opsins. They compensate for this with essential enzymes which allow heightened rod sensitivity. UV is seen by several other animal groups, including cats and insects (where it has appeared to evolve in response to predator-prey relationships).
Trade-offs in anatomy and physiology are common, and this is seen in the olfactory lobes of most avian species. Possibly due to the larger-than-average optic lobes, avian olfactory lobes are relatively small; few bird species use smell to find food. Falcons and eagles do not tend to have larger cerebellums for flying. According to comparative neuroanatomy researcher Ludwig Edinger, avian brains consist mostly of basal ganglia (responsible for instinctive behavior, rather than behavioral plasticity). Scientists have challenged some of Edinger's findings, and called for the renaming of avian nervous-system organs to reflect their similarity to those of mammals.
REM and slow-wave sleep
Avian sleep shares two similarities with that of mammals: rapid eye movement (REM) and slow-wave sleep (SWS). REM sleep is believed to have an important effect on motor functions and memory storage. EEGs show high-amplitude and low-frequency waves during REM sleep; SWS tends toward lower-amplitude, higher-frequency waves, and is believed to be a form of deep sleep. During SWS, membrane potentials in the neurons of the neocortex oscillate slowly.
A number of avian species exhibit unihemispheric slow-wave sleep: the ability to rest one half of the brain in SWS, while the other half appears to be awake. This type of sleep has also been seen in dolphins and whales. The organism is typically able to keep one eye open during this process, which allows added vigilance in high-predation environments. The evolution of this trait in birds and aquatic mammals is of interest to researchers because of the pressures involved. Unihemispheric SWS is thought to have evolved in aquatic mammals because they must return to the surface for oxygen; it is believed to help birds avoid predation, demonstrating homoplasy in the two groups.
Dove experiment
In a study of how the Barbary dove's sleep patterns are affected by flock size, D. W. Lendrum intended to prove that larger flocks reduced overall vigilance, and the apparent increase in predation risk of a smaller flock would harm the doves' sleep cycle. At the beginning of the study, the doves were caged alone or in pairs of cages containing two, three or six. They were then placed in one of two environments. In the calm environment, Lendrum walked alone past the cage between 10 am and noon; in the aggressive environment, Lendrum walked past the cage with a domesticated ferret at the same time of day. Lendrum discovered that the birds in the calm environment spent substantially more time with their eyes closed than those in the aggressive environment.
Lendrum collected data on the doves' opened- and closed-eye sleep; flocking was associated with an increase in a bird's overall eye-closure time and a decrease in its amount of eye-opening. In the presence of a predator, Lendrum found that the doves exhibited higher levels of individual vigilance and increase in open-eye sleep; this reduced the active-sleep component of their total sleep time.
Perch height
Predators are believed to play a large role in an organism's sleeping patterns. To adapt to predation, two common techniques have evolved: positioning oneself out of harm's way while sleeping, and sleeping more lightly (such as unihemispheric sleep). In birds, perch height is believed to play a significant role in sleep; lower perch height has been shown to reduce the number and length of REM sleep episodes in pigeons, and a higher perch increases REM sleep and decreases slow-wave sleep. Findings also suggest that the time spent awake by pigeons increases when nesting on lower perches. Lower perch height correlates to a higher risk of predation; REM sleep would place the pigeon in more danger, since it is a less reactive form of sleep.
Light pollution
Light is one of the more common threats to sufficient sleep for birds living in anthropogenic environments, known as "artificial light pollution at night" (ALAN). ALAN eliminates darkness, a necessity for rest. Disrupting the birds' light and dark cycles can impact circadian rhythms, eventually harming sleep patterns. Biologist Thomas Raap conducted a study which suggested that exposure to ALAN affected the sleep behavior of Eurasian blue tits (Cyanistes caeruleus). In this study, birds woke up earlier due to ALAN factors such as seasonal timekeeping. Because light usually indicates a day's passage to birds, exposure to light pollution disrupts their ability to measure the length of a day. Outside densely-populated areas, there is normally about a five-percent drop in sleep duration for blue-tit females during their nesting period. The researchers found a 50-percent reduction in the females' sleep duration during this period in urban centers, and suggested that the effects of ALAN were responsible.
References
Sleep
Birds
Bird behavior | Avian sleep | [
"Biology"
] | 1,485 | [
"Behavior by type of animal",
"Behavior",
"Animals",
"Birds",
"Sleep",
"Bird behavior"
] |
63,941,558 | https://en.wikipedia.org/wiki/WASP-26 | WASP-26 is a yellow main sequence star in the constellation of Cetus.
Star characteristics
WASP-26 is an old star close to leaving the main sequence and is part of a wide binary. The binary's projected separation is 3800 astronomical units, its companion star being a red dwarf with an effective temperature of 4600K and a visual magnitude of 13.6. WASP-26 produces a large amount of ultraviolet light due to frequent flares, with an average ultraviolet flux close to the F7 class main-sequence star WASP-1.
Planetary system
The "Hot Jupiter" class planet WASP-26b was discovered around WASP-26 in 2010. The planet would have an equilibrium temperature of 1660 K, but measured temperatures are slightly higher at 1775K and no noticeable difference exists between the day-side and the night-side of the planet. A 2011 study using the Rossiter-McLaughlin effect failed to determine the inclination of the planetary orbit to the equatorial plane of the parent star due to high stellar noise, but an initial constraint of -34° was published in 2012.
References
Planetary systems with one confirmed planet
Cetus
G-type subgiants
Planetary transit variables
26
J00182469-1516022 | WASP-26 | [
"Astronomy"
] | 248 | [
"Constellations",
"Cetus",
"Astronomy organizations",
"Wide Angle Search for Planets"
] |
63,942,140 | https://en.wikipedia.org/wiki/Mechanical%20Workshops%20Wilhelm%20Albrecht | The Mechanical Workshops Wilhelm Albrecht (MWA) () were founded in 1926 by the innovator, engineer, and entrepreneur, Wilhelm Albrecht in Berlin-Tempelhof. The logo he designed became an internationally known trademark for complete device systems for image-synchronous sound recording and processing in film and television studios since the 1950s.
History of MWA
Early years
Initially, the company developed and produced kits for radio receivers and supplied them to end users, subsequently – in advanced versions - to industrial radio manufacturers such as Blaupunkt.
In 1936, the company moved to larger premises at Juliusstrasse in Berlin's Neukölln district. In the following years, development and manufacturing concentrated on equipment for communication technology. In 1944, the factory was partially damaged by a bomb attack.
The first post-war years
In the remaining workshops and with the inventory of materials and machinery saved after the end of the war, items for everyday’s use at that time were manufactured (e. g. tobacco cutting machines). In addition, repairs of damaged industrial equipment were carried out.
Entry into film sound engineering
In this context, Albrecht came into contact with remaining companies of the Berlin film industry. As early as 1946, MWA received an order from Berlin-based Kaudel-Film to design and manufacture an optical sound camera (LTK 1) and other devices for sound recording and processing of feature films in sync with the picture. In addition, the company developed and manufactured stationary and portable sound mixing consoles for film studios.
However, Albrecht soon realized that the future of film sound recording and processing would not be the optical sound technology that had been used until then, but the magnetic sound process, which had already been experimented with in the USA. He developed the first magnetic film sound device in Europe, the so-called magnetic sound camera (MTK 1).
Development from 1950
At the beginning of 1950, MWA delivered the MTK 1 to the UFA studios in Berlin-Tempelhof where it was used for dubbing feature films and for sound recording of new productions until 1970. After a public presentation of the MTK 1, the UFA praised it as a “masterpiece of modern film equipment construction, and also in a new area of sound film technology” (see letter from the UfA dated April 4, 1950).
In terms of technology, this was already the breakthrough, but an unrestricted delivery to film studios all over the world could only take place after a protracted patent dispute had ended. Numerous further developments followed, from the MTK 1 to the MR 10 travel model, also supplemented by the KT 2 camera table as well as e. g. amplifiers and sound deleting devices (de-magnetizers). The column-shaped magnetic film recorders/reproducers were a major adaptation to the needs in studios - starting in 1950 with the MB 1, followed by numerous successor models up to the MB 51, which were used in film and television studios worldwide for decades.
In parallel to the constant further development of devices using magnetic sound technology - later also for the new medium of television - Albrecht even participated in significant constructions for phonograph technology .
In 1956, the company was transformed into a GmbH (in English: Ltd.). Wilhelm Albrecht and his wife Helene, who had headed the commercial division since 1945, were appointed managing directors with sole authorization, engineer Günter Kieß was appointed Technical Manager. The latter held this position until 1991. He extensively documented MWA equipment and systems.
In 1961, the company moved to larger premises on Maybachufer in Berlin-Neukölln. After the death of the company’s founder in 1962, his widow Helene Albrecht became general manager, a position which she held until 1974.
The continuous and innovative further development of the sound devices, which were soon supplemented by picture film transports and film scanners as well as complementary control systems was groundbreaking for the changing sophisticated production processes in film and television studios and consolidated the company's position on the international market.
In 1974, Margret Albrecht, daughter of Wilhelm and Helene Albrecht, took over the general management of the company.
After expanding the development capacities – due to its significance supported by state funding for research and development - and enlarging the production premises, as well as optimizing the operational procedures and creating additional sales channels, the production and delivery capacities were doubled within six years. In 1980, Wilhelm Albrecht GmbH was included in the ADAC travel guide listing technical places of interest in Germany.
History from the 80s
In 1984, Helene Kunow-Albrecht and Margret Nilsson-Albrecht sold their shares to Berliner Elektro Beteiligungen, which enabled the successful flotation as Berliner Elektro Holding AG (stock company).
Soon it became evident that digital technology would also largely replace the conventional analogue magnetic sound process. As a result, under the control of engineer Peter Stroetzel (general manager since 1990), the laser optical sound camera (LLK 3) for the production of optical sound negatives was developed, manufactured and, from 1996, sold to film studios and film laboratories all around the world. However, after the traditional medium film with added optical sound track was replaced by digital video technology, this market soon became saturated.
In 2002, Stroetzel, who had taken over the company shares from Berliner Elektro Holding AG in 1997, applied for insolvency, the business was finally taken over by the MWA Nova GmbH. The logo, then over 75 years old, has been preserved.
Literature
1979: Hans Borgelt: Filmstadt Berlin, Nicolaische Verlagsbuchhandlung Berlin, , pp. 58–59 and 60, see: http://d-nb.info/790229765
1980: Willi Paul: Technical Places of Interest in Germany, Volume V, Berlin, ADAC Verlag GmbH,
References
External links
Wilhelm Albrecht and his MWA
MWA - product history
Filmsound Sweden
Sven Fahlén, Europa Film Stockholm
Mobile travel magnetic sound camera (photo, around 1950)
1926 establishments in Germany
1997 disestablishments in Germany
Audio engineering | Mechanical Workshops Wilhelm Albrecht | [
"Engineering"
] | 1,258 | [
"Electrical engineering",
"Audio engineering"
] |
63,942,274 | https://en.wikipedia.org/wiki/C/2019%20Y1%20%28ATLAS%29 | C/2019 Y1 (ATLAS) is a comet with a near-parabolic orbit discovered by the ATLAS survey on 16 December 2019. It passed perihelion on 15 March 2020 at 0.84 AU from the Sun. Its orbit is very similar to C/1988 A1 (Liller), C/1996 Q1 (Tabur), C/2015 F3 (SWAN) and C/2023 V5 (Leonard), suggesting they may be fragments of a larger ancient comet.
Observations
The comet passed close to Earth in early May 2020. It was visible in the northern hemisphere sky in the spring of 2020.
References
External links
TheSkyLive Comet C/2019 Y1 (ATLAS)
astro.vanbuitenen.nl 2019Y1
Universe Today 25 March 2020 by David Dickinson
Non-periodic comets
Discoveries by ATLAS
20191216
Comets in 2019
Comets in 2020 | C/2019 Y1 (ATLAS) | [
"Astronomy"
] | 181 | [
"Astronomy stubs",
"Comet stubs"
] |
63,942,582 | https://en.wikipedia.org/wiki/WASP-25 | WASP-25 is a yellow main sequence star in the constellation of Hydra.
Star characteristics
WASP-25 is slightly metal-poor (85% of Solar amount) and is probably a young star which has just entered the main sequence.
Planetary system
The "Hot Jupiter" class planet WASP-25b was discovered around WASP-25 in 2010. The planet would have an equilibrium temperature of 1212 K.
A Rossiter-McLaughlin effect based study in 2011 found a modest misalignment of the planetary orbit to the rotational axis of the parent star, equal to 14.6 degrees. A habitability study in 2018 found WASP-25b does not adversely affect the stability of planetary orbits in the habitable zone of WASP-25.
References
Planetary systems with one confirmed planet
Hydra (constellation)
G-type main-sequence stars
Planetary transit variables
25
J13012637-2731199 | WASP-25 | [
"Astronomy"
] | 182 | [
"Constellations",
"Hydra (constellation)",
"Astronomy organizations",
"Wide Angle Search for Planets"
] |
63,942,809 | https://en.wikipedia.org/wiki/CM-4620 | CM-4620 is a drug which acts as a selective inhibitor of the calcium channel ORAI1. It has antiinflammatory effects and is being researched for the treatment of pancreatitis.
References
Anti-inflammatory agents
Calcium channel blockers
Aminopyrimidines
Benzodioxoles | CM-4620 | [
"Chemistry"
] | 64 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
63,942,956 | https://en.wikipedia.org/wiki/XL-413 | XL-413 is a drug which acts as a selective inhibitor of the enzyme cell division cycle 7-related protein kinase (CDC7). It is being researched for the treatment of some forms of cancer, and also has applications in genetic engineering.
References
Experimental cancer drugs
Enzyme inhibitors
Genetic engineering
Pyrrolidines
Pyrimidones
Chloroarenes | XL-413 | [
"Chemistry",
"Engineering",
"Biology"
] | 75 | [
"Pharmacology",
"Biological engineering",
"Bioengineering stubs",
"Biotechnology stubs",
"Genetic engineering",
"Medicinal chemistry stubs",
"Molecular biology",
"Pharmacology stubs"
] |
63,943,822 | https://en.wikipedia.org/wiki/Ethylene%20%28plant%20hormone%29 | Ethylene (=) is an unsaturated hydrocarbon gas (alkene) acting as a naturally occurring plant hormone. It is the simplest alkene gas and is the first gas known to act as a hormone. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, the abscission (or shedding) of leaves and, in aquatic and semi-aquatic species, promoting the 'escape' from submergence by means of rapid elongation of stems or leaves. This escape response is particularly important in rice farming. Commercial fruit-ripening rooms use "catalytic generators" to make ethylene gas from a liquid supply of ethanol. Typically, a gassing level of 500 to 2,000 ppm is used, for 24 to 48 hours. Care must be taken to control carbon dioxide levels in ripening rooms when gassing, as high temperature ripening () has been seen to produce CO2 levels of 10% in 24 hours.
History
Ethylene has a long history of use in agriculture. Ancient Egyptians would gash figs in order to stimulate ripening (wounding stimulates ethylene production by plant tissues). The ancient Chinese would burn incense in closed rooms to enhance the ripening of pears. In the 19th century, city dwellers noticed that gas leaks from street lights led to stunting of growth, death of flowers and premature leaf fall. In 1874, it was discovered that smoke caused pineapple fields to bloom. Smoke contains ethylene, and once this was realized the smoke was replaced with ethephon or naphthalene acetic acid, which induce ethylene production.
The scientific study of ethylene as a factor in plant physiology started in the late 19th century. In 1896, Russian botanist Dimitry Neljubow studied the response pea to illuminating gas to which they showed movement. He discovered ethylene as the active component in the light source that stimulated pea behaviour. He reported his discovery in 1901. Sarah Doubt also showed in 1917 that ethylene from illuminating gas stimulated abscission. Farmers in Florida would commonly get their crops to ripen in sheds by lighting kerosene lamps, which was originally thought to induce ripening from the heat. In 1924, Frank E. Denny discovered that it was the molecule ethylene emitted by the kerosene lamps that induced the ripening. Reporting in the Botanical Gazette, he wrote:Ethylene was very effective in bringing about the desired result, concentrations as low as one part (by volume) of ethylene in one million parts of air being sufficient to cause green lemons to turn yellow in about six to ten days... Furthermore, coloring with either ethylene or gas from the kerosene stoves caused the loss of the "buttons" (calyx, receptacle, and a portion of the peduncle)... Yellowing of the ethylene treated fruit became visible about the third or fourth day, and full yellow color was developed in six to ten days. Untreated fruit remained green during the same period of time.The same year, Denny published the experimental details separately, and also experimentally showed that use of ethylene was more advantageous than that of kerosene.
In 1934, British biologist Richard Gane discovered that the chemical constituent in ripe bananas could cause ripening of green bananas, as well as faster growth of pea. He showed that the same growth effect could be induced by ethylene. Reporting in Nature that ripe fruit (in this case Worcester Pearmain apple) produced ethylene he said:The amount of ethylene produced [by the apple] is very small—perhaps of the order of 1 cubic centimetre during the whole life-history of the fruit; and the cause of its prodigious biological activity in such small concentration is a problem for further research. Its production by apple ceases or is very much reduced in the absence of oxygen. He subsequently showed that ethylene was produced by other fruits as well, and that obtained from apple could induce seed germination and plant growth in different vegetables (but not in cereals). His conclusions were not universally accepted by other scientists. They became more convincing when William Crocker, Alfred Hitchcock, and Percy Zimmerman reported in 1935 that ethylene acts similar to auxins in causing plant growth and senescence of vegetative tissues. This established that ethylene is a plant hormone.
Ethylene biosynthesis in plants
Ethylene is produced from essentially all parts of higher plants, including leaves, stems, roots, flowers, fruits, tubers, and seeds.
Ethylene production is regulated by a variety of developmental and environmental factors. During the life of the plant, ethylene production is induced during certain stages of growth such as germination, ripening of fruits, abscission of leaves, and senescence of flowers. Ethylene production can also be induced by a variety of external aspects such as mechanical wounding, environmental stresses, and certain chemicals including auxin and other regulators. The pathway for ethylene biosynthesis is named the Yang cycle after the scientist Shang Fa Yang who made key contributions to elucidating this pathway.
Ethylene is biosynthesized from the amino acid methionine to S-adenosyl-L-methionine (SAM, also called Adomet) by the enzyme Met adenosyltransferase. SAM is then converted to 1-aminocyclopropane-1-carboxylic acid (ACC) by the enzyme ACC synthase (ACS). The activity of ACS determines the rate of ethylene production, therefore regulation of this enzyme is key for the ethylene biosynthesis. The final step requires oxygen and involves the action of the enzyme ACC-oxidase (ACO), formerly known as the ethylene forming enzyme (EFE). Ethylene biosynthesis can be induced by endogenous or exogenous ethylene. ACC synthesis increases with high levels of auxins, especially indole acetic acid (IAA) and cytokinins.
Ethylene perception in plants
Ethylene is perceived by a family of five transmembrane protein dimers such as the ETR1 protein in Arabidopsis. The genes encoding ethylene gasoreceptors have been cloned in the reference plant Arabidopsis thaliana and many other plants. Ethylene gasoreceptors are encoded by multiple genes in plant genomes. Dominant missense mutations in any of the gene family, which comprises five gasoreceptors in Arabidopsis and at least six in tomato, can confer insensitivity to ethylene. Loss-of-function mutations in multiple members of the ethylene-gasoreceptor family result in a plant that exhibits constitutive ethylene responses. DNA sequences for ethylene gasoreceptors have also been identified in many other plant species and an ethylene binding protein has even been identified in Cyanobacteria.
Ethylene response to salt stress
A large portion of the soil has been affected by over salinity and it has been known to limit the growth of many plants. Globally, the total area of saline soil was 397,000,000 ha and in continents like Africa, it makes up 2 percent of the soil. The amount of soil salinization has reached 19.5% of the irrigated land and 2.1% of the dry-land agriculture around the world. Soil salinization affects the plants using osmotic potential by net solute accumulation. The osmotic pressure in the plant is what maintains water uptake and cell turgor to help with stomatal function and other cellular mechanisms. Over generations, many plant genes have adapted, allowing plants’ phenotypes to change and built distinct mechanisms to counter salinity effects.
The plant hormone ethylene is a combatant for salinity in most plants. Ethylene is known for regulating plant growth and development and adapted to stress conditions through a complex signal transduction pathway. Central membrane proteins in plants, such as ETO2, ERS1 and EIN2, are used for ethylene signaling in many plant growth processes. ETO2, Ethylene overproducer 2, is a protein that, when mutated, will gain a function to continually produce ethylene even when there is no stress condition, causing the plant to grow short and stumpy. ERS1, Ethylene response sensor 1, is activated when ethylene is present in the signaling pathway and when mutated, it loses a function and cannot bind to ethylene. This means a response is never activated and the plant will not be able to cope with the abiotic stress. EIN2, Ethylene insensitive 2, is a protein that activates the pathway and when there is a mutation here the EIN2 will block ethylene stimulation and an ethylene response gene will not be activated. Mutations in these proteins can lead to heightened salt sensitivity and limit plant growth. The effects of salinity have been studied on Arabidopsis plants that have mutated ERS1 and EIN4 proteins. These proteins are used for ethylene signaling again certain stress conditions, such as salt and the ethylene precursor ACC is allowing suppress of any sensitivity to the salt stress. Mutations in these pathways can cause lack of ethylene signaling, causing stunt in plant growth and development.
Environmental and biological triggers of ethylene
Environmental cues such as flooding, drought, chilling, wounding, and pathogen attack can induce ethylene formation in plants. In flooding, roots suffer from lack of oxygen, or anoxia, which leads to the synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC). ACC is transported upwards in the plant and then oxidized in leaves. The ethylene produced causes nastic movements (epinasty) of the leaves, perhaps helping the plant to lose less water in compensation for an increase in resistance to water transport through oxygen-deficient roots.
Corolla senescence
The corolla of a plant refers to its set of petals. Corolla development in plants is broken into phases from anthesis to corolla wilting. The development of the corolla is directed in part by ethylene, though its concentration is highest when the plant is fertilized and no longer requires the production or maintenance of structures and compounds that attract pollinators. The role of ethylene in the developmental cycle is as a hormonal director of senescence in corolla tissue. This is evident as ethylene production and emission are maximized in developmental phases post-pollination, until corolla wilting. Ethylene-directed senescence of corolla tissue can be observed as color change in the corolla or the wilting/ death of corolla tissue. At the chemical level, ethylene mediates the reduction in the amount of fragrance volatiles produced. Fragrance volatiles act mostly by attracting pollinators. Ethylene's role in this developmental scenario is to move the plant away from a state of attracting pollinators, so it also aids in decreasing the production of these volatiles.
Ethylene production in corolla tissue does not directly cause the senescence of corolla tissue, but acts by releasing secondary products that are consistent with tissue ageing. While the mechanism of ethylene-mediated senescence are unclear, its role as a senescence-directing hormone can be confirmed by ethylene-sensitive petunia response to ethylene knockdown. Knockdown of ethylene biosynthesis genes was consistent with increased corolla longevity; inversely, up-regulation of ethylene biosynthesis gene transcription factors were consistent with a more rapid senescence of the corolla.
List of plant responses to ethylene
Seedling triple response, thickening and shortening of hypocotyl with pronounced apical hook.
Stimulation of Arabidopsis hypocotyl elongation
In pollination, when the pollen reaches the stigma, the precursor of the ethylene, ACC, is secreted to the petal, the ACC releases ethylene with ACC oxidase.
Stimulates leaf senescence
Controls root growth inhibition in compacted soils
Stimulates senescence of mature xylem cells in preparation for plant use
Induces leaf abscission
Induces seed germination
Induces root hair growth — increasing the efficiency of water and mineral absorption
Induces the growth of adventitious roots during flooding
Stimulates survival under low-oxygen conditions (hypoxia) in submerged plant tissues
Controls adaptive Translation (biology) dynamics during plant submergence
Stimulates epinasty — leaf petiole grows out, leaf hangs down and curls into itself
Stimulates fruit ripening
Induces a climacteric rise in respiration in some fruit which causes a release of additional ethylene.
Affects gravitropism
Stimulates nutation
Inhibits stem growth and stimulates stem and cell broadening and lateral branch growth outside of seedling stage (see Hyponastic response)
Interference with auxin transport (with high auxin concentrations)
Inhibits shoot growth and stomatal closing except in some water plants or habitually submerged species such as rice, Callitriche (e.g., C. platycarpa), and Rumex, where the opposite occurs to achieve an adaptive escape from submergence.
Induces flowering in pineapples
Inhibits short day induced flower initiation in Pharbitus nil and Chrysanthemum morifolium
Commercial issues
Ethylene shortens the shelf life of many fruits by hastening fruit ripening and floral senescence. Ethylene will shorten the shelf life of cut flowers and potted plants by accelerating floral senescence and floral abscission. Flowers and plants which are subjected to stress during shipping, handling, or storage produce ethylene causing a significant reduction in floral display. Flowers affected by ethylene include carnation, geranium, petunia, rose, and many others.
Ethylene can cause significant economic losses for florists, markets, suppliers, and growers. Researchers have developed several ways to inhibit ethylene, including inhibiting ethylene synthesis and inhibiting ethylene perception. Aminoethoxyvinylglycine (AVG), Aminooxyacetic acid (AOA), and silver salts are ethylene inhibitors. Inhibiting ethylene synthesis is less effective for reducing post-harvest losses since ethylene from other sources can still have an effect. By inhibiting ethylene perception, fruits, plants and flowers don't respond to ethylene produced endogenously or from exogenous sources. Inhibitors of ethylene perception include compounds that have a similar shape to ethylene, but do not elicit the ethylene response. One example of an ethylene perception inhibitor is 1-methylcyclopropene (1-MCP).
Commercial growers of bromeliads, including pineapple plants, use ethylene to induce flowering. Plants can be induced to flower either by treatment with the gas in a chamber, or by placing a banana peel next to the plant in an enclosed area.
Chrysanthemum flowering is delayed by ethylene gas, and growers have found that carbon dioxide 'burners' and the exhaust fumes from inefficient glasshouse heaters can raise the ethylene concentration to 0.05 ppmv, causing delay in flowering of commercial crops.
See also
Gas sensor protein (Gasoreceptor).
References
Further reading
External links
International Chemical Safety Card 0475
Aging-related substances in plants
Monomers
Plant hormones
GABAA receptor positive allosteric modulators
Gaseous signaling molecules
Plant growth regulators | Ethylene (plant hormone) | [
"Chemistry",
"Materials_science",
"Biology"
] | 3,333 | [
"Signal transduction",
"Senescence",
"Gaseous signaling molecules",
"Aging-related substances in plants",
"Polymer chemistry",
"Monomers"
] |
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