id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
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78,149,844 | https://en.wikipedia.org/wiki/EfficientNet | EfficientNet is a family of convolutional neural networks (CNNs) for computer vision published by researchers at Google AI in 2019. Its key innovation is compound scaling, which uniformly scales all dimensions of depth, width, and resolution using a single parameter.
EfficientNet models have been adopted in various computer vision tasks, including image classification, object detection, and segmentation.
Compound scaling
EfficientNet introduces compound scaling, which, instead of scaling one dimension of the network at a time, such as depth (number of layers), width (number of channels), or resolution (input image size), uses a compound coefficient to scale all three dimensions simultaneously. Specifically, given a baseline network, the depth, width, and resolution are scaled according to the following equations:subject to and . The condition is such that increasing by a factor of would increase the total FLOPs of running the network on an image approximately times. The hyperparameters , , and are determined by a small grid search. The original paper suggested 1.2, 1.1, and 1.15, respectively.
Architecturally, they optimized the choice of modules by neural architecture search (NAS), and found that the inverted bottleneck convolution (which they called MBConv) used in MobileNet worked well.
The EfficientNet family is a stack of MBConv layers, with shapes determined by the compound scaling. The original publication consisted of 8 models, from EfficientNet-B0 to EfficientNet-B7, with increasing model size and accuracy. EfficientNet-B0 is the baseline network, and subsequent models are obtained by scaling the baseline network by increasing .
Variants
EfficientNet has been adapted for fast inference on edge TPUs and centralized TPU or GPU clusters by NAS.
EfficientNet V2 was published in June 2021. The architecture was improved by further NAS search with more types of convolutional layers. It also introduced a training method, which progressively increases image size during training, and uses regularization techniques like dropout, RandAugment, and Mixup. The authors claim this approach mitigates accuracy drops often associated with progressive resizing.
See also
Convolutional neural network
SqueezeNet
MobileNet
You Only Look Once
References
External links
EfficientNet: Improving Accuracy and Efficiency through AutoML and Model Scaling (Google AI Blog)
Machine learning
Computer vision
Artificial neural networks
Google software | EfficientNet | [
"Engineering"
] | 489 | [
"Artificial intelligence engineering",
"Packaging machinery",
"Machine learning",
"Computer vision"
] |
78,150,207 | https://en.wikipedia.org/wiki/Palmophyllum%20umbracola | Palmophyllum umbracola is a species of algae. It is found in New Zealand waters particularly the Kermadec and Three Kings Islands, the northeastern part of the North Island of New Zealand, and the West coast of North America.
Palmophyllum umbracola grows in the form of thalli attached to substrates such as rocks and algae. The thalli are formed from spherical green cells in a gelatinous matrix. Its habitat is subtidal on rock in shallow waters extending to more than 70 meters deep.
The holotype is held at the Museum of New Zealand Te Papa Tongarewa.
References
External links
Species described in 1986
Palmophyllophyceae
Green algae species | Palmophyllum umbracola | [
"Biology"
] | 142 | [
"Algae stubs",
"Algae"
] |
78,150,693 | https://en.wikipedia.org/wiki/GeoNet%20%28New%20Zealand%29 | GeoNet is a natural hazards monitoring system in New Zealand that monitors earthquakes, large landslides, volcanoes, tsunami, and movement of land. Earthquakes and other natural hazards are automatically listed on the GeoNet website and app, and app users are given notifications to be warned about natural hazards. GeoNet was founded in 2001 by GNS Science, the Earthquake Commission and Land Information New Zealand.
Monitoring
GeoNet monitors earthquakes, large landslides, volcanoes, tsunami, and movement of land. This monitoring is done using over 1,000 instruments across the country, with data being transmitted from its sensors to GNS Science's computers in Wellington and Wairākei. On average, the monitoring system detects over 20,000 earthquakes per year. Detected earthquakes that pass a certain threshold are automatically listed on the GeoNet website. GeoNet also forecasts earthquake aftershocks for major earthquakes, such as the 2016 Kaikōura earthquake. The GeoNet app sends notifications about natural hazards to its users. An example of this is the 2016 Kaikōura earthquake, where the app had sent a total of over 109 million notifications within two days. GeoNet also posts about natural hazards on their social media pages, which are followed by over 200,000 people.
History
GeoNet was founded in 2001 by GNS Science, the Earthquake Commission and Land Information New Zealand. GeoNet was "relatively [obscure]" until the 2010 and 2011 Christchurch earthquakes occurred, when people started paying attention to the monitoring system. In December 2016 GeoNet got a funding boost of up to $3 million to improve its monitoring of and responses to natural hazards. This followed criticism of the response to the 2016 Kaikōura earthquake, especially the time it took for a tsunami alert to be issued.
In January 2019 an earthquake occurred in the Kermadec Islands and another occurred a few minutes later in Whanganui. Because it takes a few minutes for the wave forms to travel to the mainland, the monitoring system detected the two earthquakes at the same time, and was tricked into thinking that a magnitude 6 earthquake had occurred in the East Coast. A similar error occurred in 2012.
Felt reports
The GeoNet website allows people to submit felt reports and to describe the intensity of the shaking. People can choose to submit a "detailed" felt report which consists of 40 questions. After the report is submitted, a coloured square is placed on a map, at the user's location. Most people make correct submissions, although some people purposefully make false reports or make mistakes, such as a VPN causing the website to not retrieve the user's location correctly. Aucklanders have a reputation for describing small earthquakes, including ones that cannot be felt in Auckland, as having "strong" or "extreme" shaking. Sometimes people try to draw images on the map using the coloured squares, such as a phallus. Earthquakes are not the only felt reports that the website receives. It also receives reports of tsunami, with over 17,000 reports by 2020.
In 2023, GeoNet introduced a "shaking layers" map. Rather than showing squares at the locations of felt reports, it shows the median shaking at a given location. This includes locations where no one has submitted a felt report, and avoids showing possible false reports. Shortly after a large earthquake, Civil Defence may use the felt reports to gather information, such as power and communications outages, before the agency can gather information from other sources. An example of this is after the 2016 Kaikōura earthquake, where there was a lack of felt reports in Kaikōura, which suggested that there were outages there. The earthquake with the most felt reports on GeoNet had a magnitude of 6.0 and was located north-west of Paraparaumu, which gathered 60,688 felt reports in 2023.
References
2001 in New Zealand
Emergency population warning systems
Science and technology in New Zealand
Earth sciences
Earthquakes in New Zealand
Tsunamis in New Zealand
Volcanoes of New Zealand | GeoNet (New Zealand) | [
"Technology"
] | 804 | [
"Warning systems",
"Emergency population warning systems"
] |
78,150,842 | https://en.wikipedia.org/wiki/Pi%20Epsilon%20Tau | Pi Epsilon Tau () is an American honor society for petroleum engineering students. Its purpose is to maintain the standards and high ideals of the petroleum engineering profession and to build a bond between its members and the industry. The society was established in 1947 at the University of Oklahoma.
History
Faculty member Paul S. Johnson established Pi Epsilon Tau at the University of Oklahoma in November 1947 as an honor society for petroleum engineering students. It was officially recognized by the university of January 7, 1948. The honor society's purpose is to maintain the standards and high ideals of the petroleum engineering profession and to build a bond between its members and the industry.
Pi Epsilon Tau's founders planned to expand it to other campuses, creating a national honor society. Its Beta chapter was established at the University of Tulsa in 1948. Gamma was formed in 1949 at Texas Tech University in 1949. Other chapters were established at colleges across the United States.
It is governed through a national council of five membersand a national convention.
Symbols
The emblem or key of Pi Epsilon Tau is shaped like an oil derick, standing on the base of an isosceles triangle. Its flag features the emblem on top of a three-leaf clover that symbolizes Saint Patrick.
The society's colors are black and gold. Its flower is the red rose. Its pledges are called "roustabouts".
Membership
Membership in Pi Epsilon Tau is open to juniors, seniors, and graduate students studying petroleum engineeing based on academic achievement, leadership, and sociability. Pi Epsilon Tau has three class of members: active (students), honorary, and alumnus.
Chapters
Following are the chapters of Pi Epsilon Tau, with active chapters indicated in bold and inactive chapters in italics.
References
1947 establishments in Oklahoma
Student organizations established in 1947
Petroleum engineering
Engineering honor societies | Pi Epsilon Tau | [
"Engineering"
] | 364 | [
"Engineering societies",
"Petroleum engineering",
"Energy engineering",
"Engineering honor societies"
] |
78,151,021 | https://en.wikipedia.org/wiki/Conditioned%20avoidance%20response%20test | The conditioned avoidance response (CAR) test, also known as the active avoidance test, is an animal test used to identify drugs with antipsychotic-like effects. It is most commonly employed as a two-way active avoidance test with rodents. The test assesses the conditioned ability of an animal to avoid an unpleasant stimulus. Drugs that selectively suppress conditioned avoidance responses without affecting escape behavior are considered to have antipsychotic-like activity. Variations of the test, like testing for enhancement of avoidance and escape responses, have also been used to assess other drug effects, like pro-motivational and antidepressant-like effects.
Dopamine D2 receptor antagonists, like most classical antipsychotics, are active in the CAR test once occupancy of the dopamine D2 receptor reaches around 70%. Dopamine D2 receptor partial agonists like aripiprazole are likewise active in the test. Serotonin 5-HT2A receptor antagonists can enhance suppression of conditioned avoidance responses in the test. Various other types of drugs have also been found to be active in the CAR test. The effects of drugs that are active in the test are thought to be mediated by inhibition of signaling in the nucleus accumbens or ventral striatum of the mesolimbic pathway. This is a major brain area involved in behavioral activation and motivation.
The CAR test was developed in the 1950s soon after the discovery of antipsychotics. It is one of the oldest animal tests of antipsychotic-like activity. Other animal tests that are used to evaluate antipsychotic-like activity include inhibition of drug-induced hyperactivity or stereotypy, reversal of drug-induced prepulse inhibition deficits, and restoration of latent inhibition.
Description
There are several variations of the CAR test. The most common form of the test is the two-way active avoidance test (also known as the two-way discriminated shuttle box procedure). Other variations of the test include the one-way active avoidance test (also known as the one-way discriminated pole jump procedure or the pole-jumping test) and the non-discriminated operant continuous avoidance procedure (also known as the continuous avoidance test, the Sidman avoidance test, or simply the Sidman procedure).
In the two-way active avoidance test, an animal is placed in a two-compartment shuttle box with an open doorway. Then, the animal is trained to avoid an aversive stimulus (unconditioned stimulus), usually an electric footshock, on presentation of a neutral stimulus (conditioned stimulus), usually an auditory or visual stimulus like a tone or light, that shortly precedes it. The animal does this by performing a specific behavioral response, like moving to the other compartment of the box, and this response is referred to as "avoidance" or "conditioned avoidance". If the animal is late in performing the avoidance, the aversive stimulus is presented until the animal responds by moving to the compartment. This is referred to as "escape". If the animal does not escape within a certain amount of time, it is designated "escape failure". As such, there are three variables that can be measured in the CAR test: avoidance, escape, and escape failure.
Drugs that are considered to show antipsychotic-like effects selectively suppress the avoidance response without affecting escape behavior. Conversely, drugs that are not considered to have antipsychotic-like effects either have no effect in the CAR test or suppress both avoidance behavior and escape behavior at the same doses. Examples of drugs that inhibit both avoidance and escape responses include sedatives like benzodiazepines, barbiturates, and meprobamate and antidepressants like many tricyclic antidepressants (TCAs).
The CAR test is considered to have high predictive validity in the identification of potential antipsychotics and is frequently used in drug development. However, its face validity and construct validity have been described as low or absent. Moreover, a described major limitation of the model is that drugs active in the test work by impairing a normal self-preservation function; that is, avoiding an unpleasant or painful stimulus.
Another limitation of the CAR test is that selective suppression of avoidance responses by drugs is procedure-specific. In procedures besides the one-way discriminated pole jump procedure and the two-way active avoidance test, such as the Sidman procedure, antipsychotics block avoidance behavior and escapes at almost the same doses. Conversely, benzodiazepines selectively suppress avoidance behavior without affecting escape behavior in the Sidman procedure. This is opposite to what is generally described as reflecting antipsychotic-like activity. Hence, selective suppression of avoidance responses is not a specific predictor of antipsychotic efficacy, or at best, selective suppression of avoidance responses as a predictor of antipsychotic activity is dependent on the specific CAR procedure employed.
Drugs affecting the test
Active drugs
The test can detect antipsychotic-like activity both in the case of dopamine D2 receptor antagonists and in the case of drugs lacking D2 receptor antagonism. The occupancy of the D2 receptor by antagonists of this receptor required to inhibit the CAR is around 65 to 80%, which is similar to the occupancy at which therapeutic antipsychotic effects occur in humans with these drugs. Both typical antipsychotics and atypical antipsychotics are active in the CAR test. Similarly to dopamine D2 receptor antagonists, dopamine depleting agents like reserpine and tetrabenazine suppress conditioned avoidance responses and hence are active in the CAR test.
Selective serotonin 5-HT2A receptor antagonists like volinanserin (MDL-100907) and ritanserin can enhance the suppression of conditioned avoidance responses by dopamine D2 receptor antagonists. Serotonin 5-HT1A receptor agonism, for instance with buspirone, 8-OH-DPAT, or antipsychotics with concomitant 5-HT1A receptor agonism, may also enhance suppression of conditioned avoidance responses. Dopamine D2 receptor partial agonists like aripiprazole, brexpiprazole, and bifeprunox suppress conditioned avoidance responses in the CAR test similarly to dopamine D2 receptor antagonists.
Other drugs that may produce or enhance suppression of conditioned avoidance responses include serotonin 5-HT2C receptor agonists like CP-809101, WAY-163909, and meta-chlorophenylpiperazine (mCPP); α1-adrenergic receptor antagonists like prazosin; α2-adrenergic receptor antagonists like idazoxan; norepinephrine reuptake inhibitors like reboxetine; acetylcholinesterase inhibitors (and hence indirect cholinergics) like galantamine; the muscarinic acetylcholine receptor agonist xanomeline (used clinically as xanomeline/trospium); κ-opioid receptor agonists like spiradoline; AMPA receptor antagonists like GYKI-52466 and tezampanel (LY-326325); metabotropic glutamate mGlu2 and mGlu3 receptor agonists like pomaglumetad (LY-404039); and phosphodiesterase inhibitors like the PDE4 inhibitor rolipram and the PDE10A inhibitors papaverine, mardepodect (PF-2545920), and balipodect (TAK-063).
Dopamine D1 receptor antagonists have either shown no effect in the CAR, for instance ecopipam (SCH-39166), or have inhibited both avoidance and escape responses at the same doses, such as SCH-23390. However, different findings have also been reported, for instance ecopipam being effective in the CAR test. In contrast to dopamine D2 receptor antagonists, clinical trials of dopamine D1 receptor antagonists, including ecopipam and NNC 01-0687, have found that they were ineffective in the treatment of psychosis.
Inactive drugs
Various antidepressants, like tricyclic antidepressants (TCAs) as well as the selective serotonin reuptake inhibitor (SSRI) fluoxetine, reduce both avoidance and escape responses in the CAR test and hence are not considered to be active since they are not selective for avoidance responses.
Reversal agents
Dopaminergic agents, like the dopamine precursor levodopa (L-DOPA), the dopamine releasing agents amphetamine and methamphetamine, the dopamine reuptake inhibitors methylphenidate, bupropion, and nomifensine, the non-selective dopamine receptor agonist apomorphine, and the indirect dopaminergic agent amantadine, can all markedly reverse the effects of drugs like reserpine that are active in the CAR test and restore conditioned avoidance responses. Selective dopamine D1 receptor agonists. like SKF-38,393, and selective dopamine D2 receptor agonists, like quinpirole, are only weakly effective in reversing the effects of reserpine in suppressing conditioned avoidance responses when given individually. However, they are synergistic and robustly effective when administered in combination. Similarly, anticholinergics like atropine and scopolamine increase rates of conditioned avoidance responses. In contrast to dopaminergic agents, non-dopaminergic antidepressants, like many tricyclic antidepressants (TCAs), are generally ineffective in antagonizing agents that are active in the test.
Mechanism
The effects of drugs that are active in the CAR test, suppression of conditioned avoidance responses without affecting escape behavior, are thought to be mediated specifically by modulation of signaling in the nucleus accumbens shell or ventral striatum, part of the mesolimbic pathway. This area of the brain plays a major role in behavioral activation and in appetitive and aversive motivational processes. Drugs active in the CAR test may work by dampening behavioral responses to motivationally salient stimuli.
Some academics, such as Joanna Moncrieff and David Healy, maintain that antipsychotics do not actually directly treat psychotic symptoms or delusions, but rather simply induce a state of psychic indifference or blunted emotions and resultant behavioral suppression (e.g., of agitation), thereby helping to reduce the functional consequences of psychotic symptoms. This interpretation is notably consistent with the behavioral effects of antipsychotics in the CAR test, in which treated animals lose their interest or motivation in preemptively avoiding an unpleasant stimulus.
History
The CAR test was developed in the 1950s soon after the discovery of antipsychotics. It is one of the oldest and most classical tests of antipsychotic-like activity. The test was originally performed as the one-way active avoidance or pole-jumping test, but subsequently the two-way active avoidance test was introduced and became more commonly used. By 1998, the popularity of the CAR test had declined somewhat, but it continues to be frequently employed.
Test of other drug effects
The CAR test can additionally be used to assess behavioral activity or drive and associated learning. The dopamine depleting agent tetrabenazine can strongly and almost completely inhibit acquisition of conditioned avoidance responses in the shuttle box and also results in a very high rate of escape failures. Dopaminergic agents, like the catecholaminergic activity enhancers selegiline, phenylpropylaminopentane (PPAP), and benzofuranylpropylaminopentane (BPAP), can reverse the effects of tetrabenazine and enhance learning in this test.
In addition, the CAR test, by testing the capacity of drugs to enhance escape responses and thereby reverse learned helplessness, has been used as a test of antidepressant-like activity. κ-Opioid receptor antagonists like norbinaltorphimine have been found to be active in this test.
Acquisition of conditioned avoidance responses has been used as a test of anxiolytic and anxiogenic drug effects.
Since there is a learning (acquisition) phase, there have also been attempts to use the CAR test to assess activity of drugs in enhancing learning and memory. However, there have been no consistent data for this use. In addition, the CAR test may be inducing more of a behavioral reflex rather than involving higher-order memory associated with areas like the prefrontal cortex.
Other tests of antipsychotic-like activity
Other animal tests used to evaluate antipsychotic-like activity of drugs include inhibition of drug-induced stereotypy, inhibition of drug-induced hyperlocomotion or climbing behavior, and reversal of drug-induced prepulse inhibition or startle response deficits. Drugs that induce such effects include dopaminergic agents like amphetamine and apomorphine and NMDA receptor antagonists like dizocilpine (MK-801). Another test of antipsychotic-like activity is restoration of latent inhibition.
See also
Animal model of schizophrenia
Dopamine hypothesis of schizophrenia
References
Animal testing techniques
Neuroscience of schizophrenia
Psychology experiments
Schizophrenia research | Conditioned avoidance response test | [
"Chemistry"
] | 2,838 | [
"Animal testing",
"Animal testing techniques"
] |
78,151,610 | https://en.wikipedia.org/wiki/WASP-132 | WASP-132 is a star located about away in the constellation of Lupus. It is known to be orbited by two exoplanets and one more awaiting confirmation. With an apparent magnitude of 11.938, it is far too faint to be visible by the naked eye from Earth, but can be observed using a 60-mm aperture telescope as an orangish star.
Stellar characteristics
WASP-132 is a K-type main-sequence star with a spectral type of K4V, corresponding to its effective temperature of . It is about three-fourths as large as the Sun both in radius and mass, and radiates roughly a quarter of the luminosity of the Sun from its photosphere. The star is metal-rich with a metallicity (Fe/H) of . Its age estimate varies wildly between publications from Gyr to Gyr. The same goes for its rotational velocity, with presented values of and .
In 2017, a hot Jupiter exoplanet (b) was discovered to orbit the star, followed by a hot super-Earth (c) in 2022 and a cold super-Jupiter (d) in 2024, the latter being in the process of review as of October 2024. If the confirmation of planet d is accepted, this makes WASP-132 one of the only stars with planets both near a hot Jupiter and much farther out, alongside WASP-47.
Planetary system
WASP-132b
In 2017, the discovery of WASP-132b was announced alongside that of six other hot Jupiters. It was found through the analysis of transit photometry data obtained between May 2006 and June 2012 by WASP-South at the South African Astronomical Observatory, and was subsequently confirmed by radial velocity observations by the Swiss 1.2-metre Leonhard Euler Telescope's CORALIE spectrograph (March 2014 – March 2016) and transit photometry observations at TRAPPIST (5 May 2014).
The planet is relatively small for a hot Jupiter, having a mass less than half of Jupiter's and a radius 10% smaller. Due to the host star's dimness, it was the second least irradiated hot Jupiter discovered by WASP at the time of discovery, with an equilibrium temperature of (); only WASP-59b was colder at ().
WASP-132c
From TESS observations conducted in 2019, a new transit signal was found to occur every , which was confirmed to be caused by a planet with a radius 1.85 times that of Earth in 2022. Archived radial velocity data from CORALIE indicates that the mass of the planet is no more than 37.35 .
The existence of this planet implies that the nearby WASP-132b is improbable to have formed via high-eccentricity migration, the way most hot-Jupiters form. This scenario involves a giant planet that formed beyond the ice line falling into an eccentric orbit due to gravitational perturbations, which takes the planet closer to the star. Over time, the orbit circularizes much closer in than the original orbit. This is deemed unlikely to have happened to WASP-132b, since the migration would leave other nearby planets scattered or even ejected from the system as the eccentric Jupiter sweeps the vicinity of its orbit clean with its gravitational influence.
WASP-132d
In June 2024, an additional planet was reported to have been discovered in a orbit with a semi-major axis of 2.71 AU, much farther out than the previous two planets and roughly where the main belt would be in the Solar System. This planet was discovered via doppler spectroscopy (aka the radial velocity method), through the analysis of CORALIE and HARPS radial velocity data, taking into account the Rossiter-McLaughlin effect caused by the other two planets. This planet has a minimum mass of 5.16 , easily making it a super-Jupiter.
Possible distant companion
In WASP-132d's discovery paper, also described is a linear trend in the CORALIE radial velocity curves, hinting at the existence of an object located even farther out. Should it exist, it would have a minimum mass of roughly 18.5 , likely making it a brown dwarf or low-mass star, and orbit WASP-132 with a period of >18 years.
See also
WASP-84
References
K-type main-sequence stars
Lupus (constellation)
J14302619-4609330
Planetary systems with three confirmed planets
Planetary transit variables | WASP-132 | [
"Astronomy"
] | 904 | [
"Constellations",
"Lupus (constellation)",
"Astronomy organizations",
"Wide Angle Search for Planets"
] |
78,151,972 | https://en.wikipedia.org/wiki/Balipodect | Balipodect (, ; developmental code name TAK-063) is a selective phosphodiesterase 10A (PDE10A) inhibitor which was under development by Takeda for the treatment of schizophrenia.
It is active in animal models of antipsychotic-like activity, including inhibition of hyperlocomotion induced by the NMDA receptor antagonist dizocilpine (MK-801) or the dopamine releasing agent methamphetamine, inhibition of conditioned avoidance responses, and reversal of prepulse inhibition deficits.
The drug reached phase 2 clinical trials for this indication but its development was discontinued. It was reported to be poorly effective or ineffective for schizophrenia in clinical trials.
See also
Mardepodect
MK-8189
Osoresnontrine
Papaverine
Rolipram
Tofisopam
References
Abandoned drugs
Experimental drugs developed for schizophrenia
Fluoroarenes
Ketones
PDE10 inhibitors
Pyrazoles
Pyridazines | Balipodect | [
"Chemistry"
] | 201 | [
"Ketones",
"Functional groups",
"Drug safety",
"Abandoned drugs"
] |
78,152,344 | https://en.wikipedia.org/wiki/Death%20clock%20calculator | The death clock calculator is a conceptual idea of a predictive algorithm that uses personal socioeconomic, demographic, or health data (such as gender, age, or BMI) to estimate a person's lifespan and provide an estimated time of death.
Recent research
In December 2023, Nature Computational Science published a paper introducing the life2vec algorithm, developed as part of a scientific research project. Life2vec is a transformer-based model, similar to those used in natural language processing (e.g., ChatGPT or Llama), trained to analyze life trajectories. The project leverages rich registry data from Denmark, covering six million individuals, with event data related to health, demographics, and labor, recorded at a day-to-day resolution. While life2vec aims to provide insights into early mortality risks and life trends, it does not predict specific death dates, and it is not publicly available as of 2024.
Some media outlets and websites misrepresented the intent of life2vec by calling it a death clock calculator, leading to confusion and speculation about the capabilities of the algorithm. This misinterpretation has also led to fraudulent calculators pretending to use AI-based predictions, often promoted by scammers to deceive users.
References
Life expectancy
Actuarial science
Demographic economics
Senescence
Demography
Population
Duration | Death clock calculator | [
"Physics",
"Chemistry",
"Mathematics",
"Biology",
"Environmental_science"
] | 288 | [
"Duration",
"Life expectancy",
"Physical quantities",
"Time",
"Applied mathematics",
"Senescence",
"Actuarial science",
"Cellular processes",
"Demography",
"Spacetime",
"Environmental social science",
"Metabolism"
] |
78,153,053 | https://en.wikipedia.org/wiki/1ES%201959%2B650 | 1ES 1959+650 is a BL Lacertae object or a BL Lac object located in the eastern constellation of Draco, about 676 million light years from Earth. It was first discovered as an astronomical radio source in 1987 by Green Bank Radio Telescope and further categorized as both a flat-spectrum radio source and an X-ray source during the Einstein IPC Slew Survey conducted in the early 1990s.
Characteristics
1ES 1959+650 has an active galactic nucleus. It is classified as a high energy-peaked BL Lac object or a synchrotron peaked blazar with a synchrotron peak of the spectral energy distribution appearing in ultraviolet and X-ray bands.
The host galaxy of 1ES 1959+650 is a gas-rich elliptical galaxy with a dust lane located 0.8" north of its nucleus. Its structure is complex, indicating a past galaxy merger. The supermassive black hole in the center of 1ES 1959+650 is estimated to be ~ 1.3 x 108 Mʘ.
1ES 1959+650 is violently variable. It exhibits multiple outburst episodes across its electromagnetic spectrum, In its low flux state between 2000 and 2001, 1ES 1959+650 was observed with HEGRA Atmospheric Cherenkov Telescope system, which it showed a Crab flux of 5.3%. During its flaring state in May 2002, the blazar's flux level increased significantly as high as 2.2 Crab. Furthermore, an orphan flare, not accompanied by increasing activity in spectral bands, was also shown. The gamma emission in 1ES 1959+650 displays 'softer-when-brighter' evolution in a 0.1-300 GeV band while the X-ray emission showed 'harder-when-brighter' evolution in a 0.6-10 KeV band.
In addition to its variability, 1ES 1959+650 shows gamma ray flares from short to long timescales. X-ray flares were also detected in the blazar, apart from gamma ray flares. Between August 2015 and January 2016, a powerful and prolonged X-ray flare was detected in 1ES 1959+650. That same year, the second strongest X-ray flare occurred with a 5.5 month interval separation after the first flare.
The source in 1ES 1959+650 is unresolved on a kiloparsec scale. By looking at a parsec scale, it is found to be dominated by a luminous core. There is also presence of some extended unpolarized emission to the north, which the electric vector position angle is found parallel to it while the core polarization on the other hand, is roughly 1.5 percent. This suggests a component emerging towards north with average polarization of 4 percent.
References
External links
1ES 1959+650 on SIMBAD
BL Lacertae objects
Draco (constellation)
Blazars
Active galaxies
2674942
Astronomical objects discovered in 1987 | 1ES 1959+650 | [
"Astronomy"
] | 598 | [
"Constellations",
"Draco (constellation)"
] |
78,153,179 | https://en.wikipedia.org/wiki/Examples%20of%20anonymous%20functions |
Examples of anonymous functions
Numerous languages support anonymous functions, or something similar.
APL
Only some dialects support anonymous functions, either as dfns, in the tacit style or a combination of both.
f←{⍵×⍵} As a dfn
f 1 2 3
1 4 9
g←⊢×⊢ As a tacit 3-train (fork)
g 1 2 3
1 4 9
h←×⍨ As a derived tacit function
h 1 2 3
1 4 9
C (non-standard extension)
The anonymous function is not supported by standard C programming language, but supported by some C dialects, such as GCC and Clang.
GCC
The GNU Compiler Collection (GCC) supports anonymous functions, mixed by nested functions and statement expressions. It has the form:
( { return_type anonymous_functions_name (parameters) { function_body } anonymous_functions_name; } )
The following example works only with GCC. Because of how macros are expanded, the l_body cannot contain any commas outside of parentheses; GCC treats the comma as a delimiter between macro arguments.
The argument l_ret_type can be removed if __typeof__ is available; in the example below using __typeof__ on array would return testtype *, which can be dereferenced for the actual value if needed.
#include <stdio.h>
//* this is the definition of the anonymous function */
#define lambda(l_ret_type, l_arguments, l_body) \
({ \
l_ret_type l_anonymous_functions_name l_arguments \
l_body \
&l_anonymous_functions_name; \
})
#define forEachInArray(fe_arrType, fe_arr, fe_fn_body) \
{ \
int i=0; \
for(;i<sizeof(fe_arr)/sizeof(fe_arrType);i++) { fe_arr[i] = fe_fn_body(&fe_arr[i]); } \
}
typedef struct
{
int a;
int b;
} testtype;
void printout(const testtype * array)
{
int i;
for ( i = 0; i < 3; ++ i )
printf("%d %d\n", array[i].a, array[i].b);
printf("\n");
}
int main(void)
{
testtype array[] = { {0,1}, {2,3}, {4,5} };
printout(array);
/* the anonymous function is given as function for the foreach */
forEachInArray(testtype, array,
lambda (testtype, (void *item),
{
int temp = (*( testtype *) item).a;
(*( testtype *) item).a = (*( testtype *) item).b;
(*( testtype *) item).b = temp;
return (*( testtype *) item);
}));
printout(array);
return 0;
}
Clang (C, C++, Objective-C, Objective-C++)
Clang supports anonymous functions, called blocks, which have the form:
^return_type ( parameters ) { function_body }
The type of the blocks above is return_type (^)(parameters).
Using the aforementioned blocks extension and Grand Central Dispatch (libdispatch), the code could look simpler:
#include <stdio.h>
#include <dispatch/dispatch.h>
int main(void) {
void (^count_loop)() = ^{
for (int i = 0; i < 100; i++)
printf("%d\n", i);
printf("ah ah ah\n");
};
/* Pass as a parameter to another function */
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), count_loop);
/* Invoke directly */
count_loop();
return 0;
}
The code with blocks should be compiled with -fblocks and linked with -lBlocksRuntime
C++ (since C++11)
C++11 supports anonymous functions (technically function objects), called lambda expressions, which have the form:
[ captures ] ( params ) specs requires (optional) { body }
where "specs" is of the form "specifiers exception attr trailing-return-type in that order; each of these components is optional". If it is absent, the return type is deduced from return statements as if for a function with declared return type auto.
This is an example lambda expression:
[](int x, int y) { return x + y; }
C++11 also supports closures, here called captures. Captures are defined between square brackets [and ] in the declaration of lambda expression. The mechanism allows these variables to be captured by value or by reference. The following table demonstrates this:
[] // No captures, the lambda is implicitly convertible to a function pointer.
[x, &y] // x is captured by value and y is captured by reference.
[&] // Any external variable is implicitly captured by reference if used
[=] // Any external variable is implicitly captured by value if used.
[&, x] // x is captured by value. Other variables will be captured by reference.
[=, &z] // z is captured by reference. Other variables will be captured by value.
Variables captured by value are constant by default. Adding mutable after the parameter list makes them non-constant.
C++14 and newer versions support init-capture, for example:
std::unique_ptr<int> ptr = std::make_unique<int>(42);
[ptr]{ /* ... */ }; // copy assignment is deleted for a unique pointer
[ptr = std::move(ptr)]{ /* ... */ }; // ok
auto counter = [i = 0]() mutable { return i++; }; // mutable is required to modify 'i'
counter(); // 0
counter(); // 1
counter(); // 2
The following two examples demonstrate use of a lambda expression:
std::vector<int> some_list{ 1, 2, 3, 4, 5 };
int total = 0;
std::for_each(begin(some_list), end(some_list),
[&total](int x) { total += x; });
// Note that std::accumulate would be a way better alternative here...
This computes the total of all elements in the list. The variable total is stored as a part of the lambda function's closure. Since it is a reference to the stack variable total, it can change its value.
std::vector<int> some_list{ 1, 2, 3, 4, 5 };
int total = 0;
int value = 5;
std::for_each(begin(some_list), end(some_list),
[&total, value, this](int x) { total += x * value * this->some_func(); });
This will cause total to be stored as a reference, but value will be stored as a copy.
The capture of this is special. It can only be captured by value, not by reference. However in C++17, the current object can be captured by value (denoted by *this), or can be captured by reference (denoted by this). this can only be captured if the closest enclosing function is a non-static member function. The lambda will have the same access as the member that created it, in terms of protected/private members.
If this is captured, either explicitly or implicitly, then the scope of the enclosed class members is also tested. Accessing members of this does not need explicit use of this-> syntax.
The specific internal implementation can vary, but the expectation is that a lambda function that captures everything by reference will store the actual stack pointer of the function it is created in, rather than individual references to stack variables. However, because most lambda functions are small and local in scope, they are likely candidates for inlining, and thus need no added storage for references.
If a closure object containing references to local variables is invoked after the innermost block scope of its creation, the behaviour is undefined.
Lambda functions are function objects of an implementation-dependent type; this type's name is only available to the compiler. If the user wishes to take a lambda function as a parameter, the parameter type must be a template type, or they must create a std::function or a similar object to capture the lambda value. The use of the auto keyword can help store the lambda function,
auto my_lambda_func = [&](int x) { /*...*/ };
auto my_onheap_lambda_func = new auto([=](int x) { /*...*/ });
Here is an example of storing anonymous functions in variables, vectors, and arrays; and passing them as named parameters:
#include <functional>
#include <iostream>
#include <vector>
double eval(std::function<double(double)> f, double x = 2.0) {
return f(x);
}
int main() {
std::function<double(double)> f0 = [](double x) { return 1; };
auto f1 = [](double x) { return x; };
decltype(f0) fa[3] = {f0, f1, [](double x) { return x * x; }};
std::vector<decltype(f0)> fv = {f0, f1};
fv.push_back([](double x) { return x * x; });
for (size_t i = 0; i < fv.size(); i++) {
std::cout << fv[i](2.0) << std::endl;
}
for (size_t i = 0; i < 3; i++) {
std::cout << fa[i](2.0) << std::endl;
}
for (auto& f : fv) {
std::cout << f(2.0) << std::endl;
}
for (auto& f : fa) {
std::cout << f(2.0) << std::endl;
}
std::cout << eval(f0) << std::endl;
std::cout << eval(f1) << std::endl;
std::cout << eval([](double x) { return x * x; }) << std::endl;
}
A lambda expression with an empty capture specification ([]) can be implicitly converted into a function pointer with the same type as the lambda was declared with. So this is legal:
auto a_lambda_func = [](int x) -> void { /*...*/ };
void (* func_ptr)(int) = a_lambda_func;
func_ptr(4); //calls the lambda.
Since C++17, a lambda can be declared constexpr, and since C++20, consteval with the usual semantics. These specifiers go after the parameter list, like mutable. Starting from C++23, the lambda can also be static if it has no captures. The static and mutable specifiers are not allowed to be combined.
Also since C++23 a lambda expression can be recursive through explicit this as first parameter:
auto fibonacci = [](this auto self, int n) { return n <= 1 ? n : self(n - 1) + self(n - 2); };
fibonacci(7); // 13
In addition to that, C++23 modified the syntax so that the parentheses can be omitted in the case of a lambda that takes no arguments even if the lambda has a specifier. It also made it so that an attribute specifier sequence that appears before the parameter list, lambda specifiers, or noexcept specifier (there must be one of them) applies to the function call operator or operator template of the closure type. Otherwise, it applies to the type of the function call operator or operator template. Previously, such a sequence always applied to the type of the function call operator or operator template of the closure type making e.g the [[noreturn]] attribute impossible to use with lambdas.
The Boost library provides its own syntax for lambda functions as well, using the following syntax:
for_each(a.begin(), a.end(), std::cout << _1 << ' ');
Since C++14, the function parameters of a lambda can be declared with auto. The resulting lambda is called a generic lambda and is essentially an anonymous function template since the rules for type deduction of the auto parameters are the rules of template argument deduction. As of C++20, template parameters can also be declared explicitly with the following syntax:
[ captures ] < tparams > requires (optional) ( params ) specs requires (optional) { body }
C#
In C#, support for anonymous functions has deepened through the various versions of the language compiler. The language v3.0, released in November 2007 with .NET Framework v3.5, has full support of anonymous functions. C# names them lambda expressions, following the original version of anonymous functions, the lambda calculus.
// the first int is the x' type
// the second int is the return type
//
Func<int,int> foo = x => x * x;
Console.WriteLine(foo(7));
While the function is anonymous, it cannot be assigned to an implicitly typed variable, because the lambda syntax may be used for denoting an anonymous function or an expression tree, and the choice cannot automatically be decided by the compiler. E.g., this does not work:
// will NOT compile!
var foo = (int x) => x * x;
However, a lambda expression can take part in type inference and can be used as a method argument, e.g. to use anonymous functions with the Map capability available with System.Collections.Generic.List (in the ConvertAll() method):
// Initialize the list:
var values = new List<int>() { 7, 13, 4, 9, 3 };
// Map the anonymous function over all elements in the list, return the new list
var foo = values.ConvertAll(d => d * d) ;
// the result of the foo variable is of type System.Collections.Generic.List<Int32>
Prior versions of C# had more limited support for anonymous functions. C# v1.0, introduced in February 2002 with the .NET Framework v1.0, provided partial anonymous function support through the use of delegates. C# names them lambda expressions, following the original version of anonymous functions, the lambda calculus. This construct is somewhat similar to PHP delegates. In C# 1.0, delegates are like function pointers that refer to an explicitly named method within a class. (But unlike PHP, the name is unneeded at the time the delegate is used.) C# v2.0, released in November 2005 with the .NET Framework v2.0, introduced the concept of anonymous methods as a way to write unnamed inline statement blocks that can be executed in a delegate invocation. C# 3.0 continues to support these constructs, but also supports the lambda expression construct.
This example will compile in C# 3.0, and exhibits the three forms:
public class TestDriver
{
delegate int SquareDelegate(int d);
static int Square(int d)
{
return d * d;
}
static void Main(string[] args)
{
// C# 1.0: Original delegate syntax needed
// initializing with a named method.
SquareDelegate A = new SquareDelegate(Square);
System.Console.WriteLine(A(3));
// C# 2.0: A delegate can be initialized with
// inline code, called an "anonymous method". This
// method takes an int as an input parameter.
SquareDelegate B = delegate(int d) { return d * d; };
System.Console.WriteLine(B(5));
// C# 3.0. A delegate can be initialized with
// a lambda expression. The lambda takes an int, and returns an int.
// The type of x is inferred by the compiler.
SquareDelegate C = x => x * x;
System.Console.WriteLine(C(7));
// C# 3.0. A delegate that accepts one input and
// returns one output can also be implicitly declared with the Func<> type.
System.Func<int,int> D = x => x * x;
System.Console.WriteLine(D(9));
}
}
In the case of the C# 2.0 version, the C# compiler takes the code block of the anonymous function and creates a static private function. Internally, the function gets a generated name, of course; this generated name is based on the name of the method in which the Delegate is declared. But the name is not exposed to application code except by using reflection.
In the case of the C# 3.0 version, the same mechanism applies.
ColdFusion Markup Language (CFML)
Using the keyword:
fn = function(){
// statements
};
Or using an arrow function:
fn = () => {
// statements
};
fn = () => singleExpression // singleExpression is implicitly returned. There is no need for the braces or the return keyword
fn = singleParam => { // if the arrow function has only one parameter, there's no need for parentheses
// statements
}
fn = (x, y) => { // if the arrow function has zero or multiple parameters, one needs to use parentheses
// statements
}
CFML supports any statements within the function's definition, not simply expressions.
CFML supports recursive anonymous functions:
factorial = function(n){
return n > 1 ? n * factorial(n-1) : 1;
};
CFML anonymous functions implement closure.
D
D uses inline delegates to implement anonymous functions. The full syntax for an inline delegate is
return_type delegate(arguments){/*body*/}
If unambiguous, the return type and the keyword delegate can be omitted.
(x){return x*x;}
delegate (x){return x*x;} // if more verbosity is needed
(int x){return x*x;} // if parameter type cannot be inferred
delegate (int x){return x*x;} // ditto
delegate double(int x){return x*x;} // if return type must be forced manually
Since version 2.0, D allocates closures on the heap unless the compiler can prove it is unnecessary; the scope keyword can be used for forcing stack allocation.
Since version 2.058, it is possible to use shorthand notation:
x => x*x;
(int x) => x*x;
(x,y) => x*y;
(int x, int y) => x*y;
An anonymous function can be assigned to a variable and used like this:
auto sqr = (double x){return x*x;};
double y = sqr(4);
Dart
Dart supports anonymous functions.
var sqr = (x) => x * x;
print(sqr(5));
or
print(((x) => x * x)(5));
Delphi
Delphi introduced anonymous functions in version 2009.
program demo;
type
TSimpleProcedure = reference to procedure;
TSimpleFunction = reference to function(const x: string): Integer;
var
x1: TSimpleProcedure;
y1: TSimpleFunction;
begin
x1 := procedure
begin
Writeln('Hello World');
end;
x1; //invoke anonymous method just defined
y1 := function(const x: string): Integer
begin
Result := Length(x);
end;
Writeln(y1('bar'));
end.
PascalABC.NET
PascalABC.NET supports anonymous functions using lambda syntax
begin
var n := 10000000;
var pp := (1..n)
.Select(x -> (Random, Random))
.Where(p -> Sqr(p[0]) + Sqr(p[1]) < 1)
.Count / n * 4;
Print(pp);
end.
Elixir
Elixir uses the closure fn for anonymous functions.
sum = fn(a, b) -> a + b end
sum.(4, 3)
#=> 7
square = fn(x) -> x * x end
Enum.map [1, 2, 3, 4], square
#=> [1, 4, 9, 16]
Erlang
Erlang uses a syntax for anonymous functions similar to that of named functions.
% Anonymous function bound to the Square variable
Square = fun(X) -> X * X end.
% Named function with the same functionality
square(X) -> X * X.
Go
Go supports anonymous functions.
foo := func(x int) int {
return x * x
}
fmt.Println(foo(10))
Haskell
Haskell uses a concise syntax for anonymous functions (lambda expressions). The backslash is supposed to resemble λ.
\x -> x * x
Lambda expressions are fully integrated with the type inference engine, and support all the syntax and features of "ordinary" functions (except for the use of multiple definitions for pattern-matching, since the argument list is only specified once).
map (\x -> x * x) [1..5] -- returns [1, 4, 9, 16, 25]
The following are all equivalent:
f x y = x + y
f x = \y -> x + y
f = \x y -> x + y
Haxe
In Haxe, anonymous functions are called lambda, and use the syntax function(argument-list) expression; .
var f = function(x) return x*x;
f(8); // 64
(function(x,y) return x+y)(5,6); // 11
Java
Java supports anonymous functions, named Lambda Expressions, starting with JDK 8.
A lambda expression consists of a comma separated list of the formal parameters enclosed in parentheses, an arrow token (->), and a body. Data types of the parameters can always be omitted, as can the parentheses if there is only one parameter. The body can consist of one statement or a statement block.
// with no parameter
() -> System.out.println("Hello, world.")
// with one parameter (this example is an identity function).
a -> a
// with one expression
(a, b) -> a + b
// with explicit type information
(long id, String name) -> "id: " + id + ", name:" + name
// with a code block
(a, b) -> { return a + b; }
// with multiple statements in the lambda body. It needs a code block.
// This example also includes two nested lambda expressions (the first one is also a closure).
(id, defaultPrice) -> {
Optional<Product> product = productList.stream().filter(p -> p.getId() == id).findFirst();
return product.map(p -> p.getPrice()).orElse(defaultPrice);
}
Lambda expressions are converted to "functional interfaces" (defined as interfaces that contain only one abstract method in addition to one or more default or static methods), as in the following example:
public class Calculator {
interface IntegerMath {
int operation(int a, int b);
default IntegerMath swap() {
return (a, b) -> operation(b, a);
}
}
private static int apply(int a, int b, IntegerMath op) {
return op.operation(a, b);
}
public static void main(String... args) {
IntegerMath addition = (a, b) -> a + b;
IntegerMath subtraction = (a, b) -> a - b;
System.out.println("40 + 2 = " + apply(40, 2, addition));
System.out.println("20 - 10 = " + apply(20, 10, subtraction));
System.out.println("10 - 20 = " + apply(20, 10, subtraction.swap()));
}
}
In this example, a functional interface called IntegerMath is declared. Lambda expressions that implement IntegerMath are passed to the apply() method to be executed. Default methods like swap define methods on functions.
Java 8 introduced another mechanism named method reference (the :: operator) to create a lambda on an existing method. A method reference does not indicate the number or types of arguments because those are extracted from the abstract method of the functional interface.
IntBinaryOperator sum = Integer::sum;
In the example above, the functional interface IntBinaryOperator declares an abstract method int applyAsInt(int, int), so the compiler looks for a method int sum(int, int) in the class java.lang.Integer.
Differences compared to Anonymous Classes
Anonymous classes of lambda-compatible interfaces are similar, but not exactly equivalent, to lambda expressions.
To illustrate, in the following example, and are both instances of that add their two parameters:
IntegerMath anonymousClass = new IntegerMath() {
@Override
public int operation(int a, int b) {
return a + b;
}
};
IntegerMath lambdaExpression = (a, b) -> a + b;
The main difference here is that the lambda expression does not necessarily need to allocate a new instance for the , and can return the same instance every time this code is run.
Additionally, in the OpenJDK implementation at least, lambdas are compiled to instructions, with the lambda body inserted as a static method into the surrounding class, rather than generating a new class file entirely.
Java limitations
Java 8 lambdas have the following limitations:
Lambdas can throw checked exceptions, but such lambdas will not work with the interfaces used by the Collection API.
Variables that are in-scope where the lambda is declared may only be accessed inside the lambda if they are effectively final, i.e. if the variable is not mutated inside or outside of the lambda scope.
JavaScript
JavaScript/ECMAScript supports anonymous functions.
alert((function(x){
return x * x;
})(10));
ES6 supports "arrow function" syntax, where a => symbol separates the anonymous function's parameter list from the body:
alert((x => x * x)(10));
This construct is often used in Bookmarklets. For example, to change the title of the current document (visible in its window's title bar) to its URL, the following bookmarklet may seem to work.
document.title=location.href;
However, as the assignment statement returns a value (the URL itself), many browsers actually create a new page to display this value.
Instead, an anonymous function, that does not return a value, can be used:
(function(){document.title=location.href;})();
The function statement in the first (outer) pair of parentheses declares an anonymous function, which is then executed when used with the last pair of parentheses. This is almost equivalent to the following, which populates the environment with f unlike an anonymous function.
var f = function(){document.title=location.href;}; f();
Use void() to avoid new pages for arbitrary anonymous functions:
void(function(){return document.title=location.href;}());
or just:
void(document.title=location.href);
JavaScript has syntactic subtleties for the semantics of defining, invoking and evaluating anonymous functions. These subliminal nuances are a direct consequence of the evaluation of parenthetical expressions. The following constructs which are called immediately-invoked function expression illustrate this:
(function(){ ... }()) and
(function(){ ... })()
Representing "function(){ ... }" by f, the form of the constructs are
a parenthetical within a parenthetical (f()) and a parenthetical applied to a parenthetical (f)().
Note the general syntactic ambiguity of a parenthetical expression, parenthesized arguments to a function and the parentheses around the formal parameters in a function definition. In particular, JavaScript defines a , (comma) operator in the context of a parenthetical expression. It is no mere coincidence that the syntactic forms coincide for an expression and a function's arguments (ignoring the function formal parameter syntax)! If f is not identified in the constructs above, they become (()) and ()(). The first provides no syntactic hint of any resident function but the second MUST evaluate the first parenthetical as a function to be legal JavaScript. (Aside: for instance, the ()'s could be ([],{},42,"abc",function(){}) as long as the expression evaluates to a function.)
Also, a function is an Object instance (likewise objects are Function instances) and the object literal notation brackets, {} for braced code, are used when defining a function this way (as opposed to using new Function(...)). In a very broad non-rigorous sense (especially since global bindings are compromised), an arbitrary sequence of braced JavaScript statements, {stuff}, can be considered to be a fixed point of
(function(){( function(){( ... {( function(){stuff}() )} ... )}() )}() )
More correctly but with caveats,
( function(){stuff}() ) ~=
A_Fixed_Point_of(
function(){ return function(){ return ... { return function(){stuff}() } ... }() }()
)
Note the implications of the anonymous function in the JavaScript fragments that follow:
function(){ ... }() without surrounding ()'s is generally not legal
(f=function(){ ... }) does not "forget" f globally unlike (function f(){ ... })
Performance metrics to analyze the space and time complexities of function calls, call stack, etc. in a JavaScript interpreter engine implement easily with these last anonymous function constructs. From the implications of the results, it is possible to deduce some of an engine's recursive versus iterative implementation details, especially tail-recursion.
Julia
In Julia anonymous functions are defined using the syntax (arguments)->(expression),
julia> f = x -> x*x; f(8)
64
julia> ((x,y)->x+y)(5,6)
11
Kotlin
Kotlin supports anonymous functions with the syntax {arguments -> expression},
val sum = { x: Int, y: Int -> x + y }
sum(5,6) // returns 11
val even = { x: Int -> x%2==0}
even(4) // returns true
Lisp
Lisp and Scheme support anonymous functions using the "lambda" construct, which is a reference to lambda calculus. Clojure supports anonymous functions with the "fn" special form and #() reader syntax.
(lambda (arg) (* arg arg))
Common Lisp
Common Lisp has the concept of lambda expressions. A lambda expression is written as a list with the symbol "lambda" as its first element. The list then contains the argument list, documentation or declarations and a function body. Lambda expressions can be used inside lambda forms and with the special operator "function".
(function (lambda (arg) (do-something arg)))
"function" can be abbreviated as #'. Also, macro lambda exists, which expands into a function form:
; using sharp quote
#'(lambda (arg) (do-something arg))
; using the lambda macro:
(lambda (arg) (do-something arg))
One typical use of anonymous functions in Common Lisp is to pass them to higher-order functions like mapcar, which applies a function to each element of a list and returns a list of the results.
(mapcar #'(lambda (x) (* x x))
'(1 2 3 4))
; -> (1 4 9 16)
The lambda form in Common Lisp allows a lambda expression to be written in a function call:
((lambda (x y)
(+ (sqrt x) (sqrt y)))
10.0
12.0)
Anonymous functions in Common Lisp can also later be given global names:
(setf (symbol-function 'sqr)
(lambda (x) (* x x)))
; which allows us to call it using the name SQR:
(sqr 10.0)
Scheme
Scheme's named functions is simply syntactic sugar for anonymous functions bound to names:
(define (somename arg)
(do-something arg))
expands (and is equivalent) to
(define somename
(lambda (arg)
(do-something arg)))
Clojure
Clojure supports anonymous functions through the "fn" special form:
(fn [x] (+ x 3))
There is also a reader syntax to define a lambda:
#(+ % %2%3) ; Defines an anonymous function that takes three arguments and sums them.
Like Scheme, Clojure's "named functions" are simply syntactic sugar for lambdas bound to names:
(defn func [arg] (+ 3 arg))
expands to:
(def func (fn [arg] (+ 3 arg)))
Lua
In Lua (much as in Scheme) all functions are anonymous. A named function in Lua is simply a variable holding a reference to a function object.
Thus, in Lua
function foo(x) return 2*x end
is just syntactical sugar for
foo = function(x) return 2*x end
An example of using anonymous functions for reverse-order sorting:
table.sort(network, function(a,b)
return a.name > b.name
end)
Wolfram Language, Mathematica
The Wolfram Language is the programming language of Mathematica. Anonymous functions are important in programming the latter. There are several ways to create them. Below are a few anonymous functions that increment a number. The first is the most common. #1 refers to the first argument and & marks the end of the anonymous function.
#1+1&
Function[x,x+1]
x \[Function] x+1
So, for instance:
f:= #1^2&;f[8]
64
#1+#2&[5,6]
11
Also, Mathematica has an added construct to make recursive anonymous functions. The symbol '#0' refers to the entire function. The following function calculates the factorial of its input:
If[#1 == 1, 1, #1 * #0[#1-1]]&
For example, 6 factorial would be:
If[#1 == 1, 1, #1 * #0[#1-1]]&[6]
720
MATLAB, Octave
Anonymous functions in MATLAB or Octave are defined using the syntax @(argument-list)expression. Any variables that are not found in the argument list are inherited from the enclosing scope and are captured by value.
>> f = @(x)x*x; f(8)
ans = 64
>> (@(x,y)x+y)(5,6) % Only works in Octave
ans = 11
Maxima
In Maxima anonymous functions are defined using the syntax lambda(argument-list,expression),
f: lambda([x],x*x); f(8);
64
lambda([x,y],x+y)(5,6);
11
ML
The various dialects of ML support anonymous functions.
OCaml
Anonymous functions in OCaml are functions without a declared name. Here is an example of an anonymous function that multiplies its input by two:
fun x -> x*2
In the example, fun is a keyword indicating that the function is an anonymous function. We are passing in an argument x and -> to separate the argument from the body.
F#
F# supports anonymous functions, as follows:
(fun x -> x * x) 20 // 400
Standard ML
Standard ML supports anonymous functions, as follows:
fn arg => arg * arg
Nim
Nim supports multi-line multi-expression anonymous functions.
var anon = proc (var1, var2: int): int = var1 + var2
assert anon(1, 2) == 3
Multi-line example:
var anon = func (x: int): bool =
if x > 0:
result = true
else:
result = false
assert anon(9)
Anonymous functions may be passed as input parameters of other functions:
var cities = @["Frankfurt", "Tokyo", "New York"]
cities.sort(
proc (x, y: string): int = cmp(x.len, y.len)
)
An anonymous function is basically a function without a name.
Perl
Perl 5
Perl 5 supports anonymous functions, as follows:
(sub { print "I got called\n" })->(); # 1. fully anonymous, called as created
my $squarer = sub { my $x = shift; $x * $x }; # 2. assigned to a variable
sub curry {
my ($sub, @args) = @_;
return sub { $sub->(@args, @_) }; # 3. as a return value of another function
}
# example of currying in Perl programming
sub sum { my $tot = 0; $tot += $_ for @_; $tot } # returns the sum of its arguments
my $curried = curry \&sum, 5, 7, 9;
print $curried->(1,2,3), "\n"; # prints 27 ( = 5 + 7 + 9 + 1 + 2 + 3 )
Other constructs take bare blocks as arguments, which serve a function similar to lambda functions of one parameter, but do not have the same parameter-passing convention as functions -- @_ is not set.
my @squares = map { $_ * $_ } 1..10; # map and grep don't use the 'sub' keyword
my @square2 = map $_ * $_, 1..10; # braces unneeded for one expression
my @bad_example = map { print for @_ } 1..10; # values not passed like normal Perl function
PHP
Before 4.0.1, PHP had no anonymous function support.
PHP 4.0.1 to 5.3
PHP 4.0.1 introduced the create_function which was the initial anonymous function support. This function call makes a new randomly named function and returns its name (as a string)
$foo = create_function('$x', 'return $x*$x;');
$bar = create_function("\$x", "return \$x*\$x;");
echo $foo(10);
The argument list and function body must be in single quotes, or the dollar signs must be escaped.
Otherwise, PHP assumes "$x" means the variable $x and will substitute it into the string (despite possibly not existing) instead of leaving "$x" in the string.
For functions with quotes or functions with many variables, it can get quite tedious to ensure the intended function body is what PHP interprets.
Each invocation of create_function makes a new function, which exists for the rest of the program, and cannot be garbage collected, using memory in the program irreversibly. If this is used to create anonymous functions many times, e.g., in a loop, it can cause problems such as memory bloat.
PHP 5.3
PHP 5.3 added a new class called Closure and magic method __invoke() that makes a class instance invocable.
$x = 3;
$func = function($z) { return $z * 2; };
echo $func($x); // prints 6
In this example, $func is an instance of Closure and echo $func($x) is equivalent to echo $func->__invoke($x).
PHP 5.3 mimics anonymous functions but it does not support true anonymous functions because PHP functions are still not first-class objects.
PHP 5.3 does support closures but the variables must be explicitly indicated as such:
$x = 3;
$func = function() use(&$x) { $x *= 2; };
$func();
echo $x; // prints 6
The variable $x is bound by reference so the invocation of $func modifies it and the changes are visible outside of the function.
PHP 7.4
Arrow functions were introduced in PHP 7.4
$x = 3;
$func = fn($z) => $z * 2;
echo $func($x); // prints 6
Prolog's dialects
Logtalk
Logtalk uses the following syntax for anonymous predicates (lambda expressions):
{FreeVar1, FreeVar2, ...}/[LambdaParameter1, LambdaParameter2, ...]>>Goal
A simple example with no free variables and using a list mapping predicate is:
| ?- meta::map([X,Y]>>(Y is 2*X), [1,2,3], Ys).
Ys = [2,4,6]
yes
Currying is also supported. The above example can be written as:
| ?- meta::map([X]>>([Y]>>(Y is 2*X)), [1,2,3], Ys).
Ys = [2,4,6]
yes
Visual Prolog
Anonymous functions (in general anonymous predicates) were introduced in Visual Prolog in version 7.2. Anonymous predicates can capture values from the context. If created in an object member, it can also access the object state (by capturing This).
mkAdder returns an anonymous function, which has captured the argument X in the closure. The returned function is a function that adds X to its argument:
clauses
mkAdder(X) = { (Y) = X+Y }.
Python
Python supports simple anonymous functions through the lambda form. The executable body of the lambda must be an expression and can't be a statement, which is a restriction that limits its utility. The value returned by the lambda is the value of the contained expression. Lambda forms can be used anywhere ordinary functions can. However these restrictions make it a very limited version of a normal function. Here is an example:
>>> foo = lambda x: x * x
>>> foo(10)
100
In general, the Python convention encourages the use of named functions defined in the same scope as one might typically use an anonymous function in other languages. This is acceptable as locally defined functions implement the full power of closures and are almost as efficient as the use of a lambda in Python. In this example, the built-in power function can be said to have been curried:
>>> def make_pow(n):
... def fixed_exponent_pow(x):
... return pow(x, n)
... return fixed_exponent_pow
...
>>> sqr = make_pow(2)
>>> sqr(10)
100
>>> cub = make_pow(3)
>>> cub(10)
1000
R
In R the anonymous functions are defined using the syntax function(argument-list)expression , which has shorthand since version 4.1.0 \, akin to Haskell.
> f <- function(x)x*x; f(8)
[1] 64
> (function(x,y)x+y)(5,6)
[1] 11
> # Since R 4.1.0
> (\(x,y) x+y)(5, 6)
[1] 11
Raku
In Raku, all blocks (even those associated with if, while, etc.) are anonymous functions. A block that is not used as an rvalue is executed immediately.
fully anonymous, called as created
{ say "I got called" };
assigned to a variable
my $squarer1 = -> $x { $x * $x }; # 2a. pointy block
my $squarer2 = { $^x * $^x }; # 2b. twigil
my $squarer3 = { my $x = shift @_; $x * $x }; # 2c. Perl 5 style
currying
sub add ($m, $n) { $m + $n }
my $seven = add(3, 4);
my $add_one = &add.assuming(m => 1);
my $eight = $add_one($seven);
WhateverCode object
my $w = * - 1; # WhateverCode object
my $b = { $_ - 1 }; # same functionality, but as Callable block
Ruby
Ruby supports anonymous functions by using a syntactical structure called block. There are two data types for blocks in Ruby. Procs behave similarly to closures, whereas lambdas behave more analogous to an anonymous function. When passed to a method, a block is converted into a Proc in some circumstances.
# Example 1:
# Purely anonymous functions using blocks.
ex = [16.2, 24.1, 48.3, 32.4, 8.5]
=> [16.2, 24.1, 48.3, 32.4, 8.5]
ex.sort_by { |x| x - x.to_i } # Sort by fractional part, ignoring integer part.
=> [24.1, 16.2, 48.3, 32.4, 8.5]
# Example 2:
# First-class functions as an explicit object of Proc -
ex = Proc.new { puts "Hello, world!" }
=> #<Proc:0x007ff4598705a0@(irb):7>
ex.call
Hello, world!
=> nil
# Example 3:
# Function that returns lambda function object with parameters
def multiple_of?(n)
lambda{|x| x % n == 0}
end
=> nil
multiple_four = multiple_of?(4)
=> #<Proc:0x007ff458b45f88@(irb):12 (lambda)>
multiple_four.call(16)
=> true
multiple_four[15]
=> false
Rust
In Rust, anonymous functions are called closures. They are defined using the following syntax:
|<parameter-name>: <type>| -> <return-type> { <body> };
For example:
let f = |x: i32| -> i32 { x * 2 };
With type inference, however, the compiler is able to infer the type of each parameter and the return type, so the above form can be written as:
let f = |x| { x * 2 };
With closures with a single expression (i.e. a body with one line) and implicit return type, the curly braces may be omitted:
let f = |x| x * 2;
Closures with no input parameter are written like so:
let f = || println!("Hello, world!");
Closures may be passed as input parameters of functions that expect a function pointer:
// A function which takes a function pointer as an argument and calls it with
// the value '5'.
fn apply(f: fn(i32) -> i32) -> i32 {
// No semicolon, to indicate an implicit return
f(5)
}
fn main() {
// Defining the closure
let f = |x| x * 2;
println!("{}", apply(f)); // 10
println!("{}", f(5)); // 10
}
However, one may need complex rules to describe how values in the body of the closure are captured. They are implemented using the Fn, FnMut, and FnOnce traits:
Fn: the closure captures by reference (&T). They are used for functions that can still be called if they only have reference access (with &) to their environment.
FnMut: the closure captures by mutable reference (&mut T). They are used for functions that can be called if they have mutable reference access (with &mut) to their environment.
FnOnce: the closure captures by value (T). They are used for functions that are only called once.
With these traits, the compiler will capture variables in the least restrictive manner possible. They help govern how values are moved around between scopes, which is largely important since Rust follows a lifetime construct to ensure values are "borrowed" and moved in a predictable and explicit manner.
The following demonstrates how one may pass a closure as an input parameter using the Fn trait:
// A function that takes a value of type F (which is defined as
// a generic type that implements the 'Fn' trait, e.g. a closure)
// and calls it with the value '5'.
fn apply_by_ref<F>(f: F) -> i32
where F: Fn(i32) -> i32
{
f(5)
}
fn main() {
let f = |x| {
println!("I got the value: {}", x);
x * 2
};
// Applies the function before printing its return value
println!("5 * 2 = {}", apply_by_ref(f));
}
// ~~ Program output ~~
// I got the value: 5
// 5 * 2 = 10
The previous function definition can also be shortened for convenience as follows:
fn apply_by_ref(f: impl Fn(i32) -> i32) -> i32 {
f(5)
}
Scala
In Scala, anonymous functions use the following syntax:
(x: Int, y: Int) => x + y
In certain contexts, like when an anonymous function is a parameter being passed to another function, the compiler can infer the types of the parameters of the anonymous function and they can be omitted in the syntax. In such contexts, it is also possible to use a shorthand for anonymous functions using the underscore character to introduce unnamed parameters.
val list = List(1, 2, 3, 4)
list.reduceLeft( (x, y) => x + y )
// Here, the compiler can infer that the types of x and y are both Int.
// Thus, it needs no type annotations on the parameters of the anonymous function.
list.reduceLeft( _ + _ )
// Each underscore stands for a new unnamed parameter in the anonymous function.
// This results in an even shorter equivalent to the anonymous function above.
Smalltalk
In Smalltalk anonymous functions are called blocks and they are invoked (called) by sending them a "value" message. If several arguments are to be passed, a "value:...value:" message with a corresponding number of value arguments must be used.
For example, in GNU Smalltalk,
st> f:=[:x|x*x]. f value: 8 .
64
st> [:x :y|x+y] value: 5 value: 6 .
11
Smalltalk blocks are technically closures, allowing them to outlive their defining scope and still refer to the variables declared therein.
st> f := [:a|[:n|a+n]] value: 100 .
a BlockClosure
"returns the inner block, which adds 100 (captured in "a" variable) to its argument."
st> f value: 1 .
101
st> f value: 2 .
102
Swift
In Swift, anonymous functions are called closures. The syntax has following form:
{ (parameters) -> returnType in
statement
}
For example:
{ (s1: String, s2: String) -> Bool in
return s1 > s2
}
For sake of brevity and expressiveness, the parameter types and return type can be omitted if these can be inferred:
{ s1, s2 in return s1 > s2 }
Similarly, Swift also supports implicit return statements for one-statement closures:
{ s1, s2 in s1 > s2 }
Finally, the parameter names can be omitted as well; when omitted, the parameters are referenced using shorthand argument names, consisting of the $ symbol followed by their position (e.g. $0, $1, $2, etc.):
{ $0 > $1 }
Tcl
In Tcl, applying the anonymous squaring function to 2 looks as follows:
apply {x {expr {$x*$x}}} 2
# returns 4
This example involves two candidates for what it means to be a function in Tcl. The most generic is usually called a command prefix, and if the variable f holds such a function, then the way to perform the function application f(x) would be
{*}$f $x
where {*} is the expansion prefix (new in Tcl 8.5). The command prefix in the above example is
apply {x {expr {$x*$x}}} Command names can be bound to command prefixes by means of the interp alias command. Command prefixes support currying. Command prefixes are very common in Tcl APIs.
The other candidate for "function" in Tcl is usually called a lambda, and appears as the {x {expr {$x*$x}}} part of the above example. This is the part which caches the compiled form of the anonymous function, but it can only be invoked by being passed to the apply command. Lambdas do not support currying, unless paired with an apply to form a command prefix. Lambdas are rare in Tcl APIs.
Vala
In Vala, anonymous functions are supported as lambda expressions.
delegate int IntOp (int x, int y);
void main () {
IntOp foo = (x, y) => x * y;
stdout.printf("%d\n", foo(10,5));
}
Visual Basic .NET
Visual Basic .NET 2008 introduced anonymous functions through the lambda form. Combined with implicit typing, VB provides an economical syntax for anonymous functions. As with Python, in VB.NET, anonymous functions must be defined on one line; they cannot be compound statements. Further, an anonymous function in VB.NET must truly be a VB.NET Function - it must return a value.
Dim foo = Function(x) x * x
Console.WriteLine(foo(10))
Visual Basic.NET 2010 added support for multiline lambda expressions and anonymous functions without a return value. For example, a function for use in a Thread.
Dim t As New System.Threading.Thread(Sub ()
For n As Integer = 0 To 10 'Count to 10
Console.WriteLine(n) 'Print each number
Next
End Sub
)
t.Start()
References
Functions and mappings | Examples of anonymous functions | [
"Mathematics"
] | 12,349 | [
"Mathematical analysis",
"Functions and mappings",
"Mathematical relations",
"Mathematical objects"
] |
78,153,188 | https://en.wikipedia.org/wiki/Carotenoid%20biosynthesis | Carotenoids are a class of natural pigments synthesized by various organisms, including plants, algae, and photosynthetic bacteria. They are characterized by their vibrant yellow, orange, and red colors, which contribute significantly to the coloration of fruits and vegetables. Carotenoids play essential roles in photosynthesis and offer various health benefits, such as antioxidant properties and serving as precursors to vitamin A.
Biosynthetic pathway
Carotenoid biosynthesis occurs primarily in the plastids of plant cells, particularly within chloroplasts and chromoplasts. The biosynthetic pathway initiates with the condensation of two molecules of geranylgeranyl pyrophosphate (GGPP), a 20-carbon isoprenoid precursor. The key steps in this pathway are as follows:
Formation of phytoene: The enzyme phytoene synthase (PSY) catalyzes the condensation of two GGPP molecules to produce phytoene, a colorless carotenoid.
Desaturation to lycopene: Phytoene undergoes a series of desaturation reactions facilitated by enzymes such as phytoene desaturase (PDS) and ζ-carotene isomerase (Z-ISO), resulting in the formation of lycopene, a red carotenoid.
Cyclization to carotenoids: Lycopene is cyclized into various carotenoids, including α-carotene and β-carotene, through the action of lycopene cyclase (LCY), which catalyzes cyclization at the ends of the lycopene molecule.
Further modifications: Subsequent modifications, such as hydroxylation and oxidation, lead to the formation of xanthophylls (e.g., lutein and zeaxanthin) and other derivatives.
Key enzymes
Several enzymes play critical roles in the carotenoid biosynthetic pathway:
Phytoene synthase (PSY): Catalyzes the first committed step in carotenoid biosynthesis, converting GGPP into phytoene.
Phytoene desaturase (PDS): Introduces double bonds into phytoene, facilitating its conversion into lycopene.
Lycopene cyclase (LCY): Responsible for the cyclization of lycopene into α-carotene or β-carotene.
Carotenoid hydroxylases: Enzymes such as lutein epoxide cyclase (LUT) introduce hydroxyl groups into carotenoids, leading to the formation of xanthophylls.
Regulation
The regulation of carotenoid biosynthesis is influenced by various factors, including:
Gene Expression: Many carotenoid biosynthetic genes are upregulated by light, enhancing the expression of PSY and subsequently increasing carotenoid production.
Hormonal Regulation: Phytohormones such as auxins and abscisic acid modulate carotenoid biosynthesis. Notably, abscisic acid enhances carotenoid accumulation under stress conditions.
Environmental Factors: Stressors like drought or pathogen attack can trigger carotenoid accumulation as a protective response, thereby enhancing plant resilience.
Significance
In plants
Carotenoids play roles in photosynthetic organisms by:
Protecting chlorophyll from photodamage.
Scavenging reactive oxygen species (ROS).
Attracting pollinators and seed dispersers through their bright colors.
In human health
Carotenoids, especially provitamin A carotenoids such as β-carotene, are essential for human health. Their benefits include:
Supporting vision, particularly in low-light conditions.
Enhancing immune function.
Contributing to skin health.
Providing antioxidant properties that may reduce the risk of chronic diseases, including cardiovascular diseases and certain cancers.
References
Carotenoids
Biosynthesis | Carotenoid biosynthesis | [
"Chemistry",
"Biology"
] | 849 | [
"Biomarkers",
"Carotenoids",
"Biosynthesis",
"Chemical synthesis",
"Metabolism"
] |
78,154,154 | https://en.wikipedia.org/wiki/Hwatsing%20Technology | Hwatsing Technology (Hwatsing; ) is a partially state-owned publicly listed Chinese company headquartered in Tianjin that manufactures semiconductor chip production equipment.
Its most notable product offerings are in chemical-mechanical polishing (CMP) machines.
Background
In 2000 at Tsinghua University, Luo Jianbin and Lu Xinchun began their research on CMP technology.
In April 2013, Tsinghua Holdings and the Tianjin Municipal Government established Hwatsing to commercialize the technology developed from the CMP project. Hwatsing produced China's first 12-inch CMP machine.
On 9 June 2022, Hwatsing held its initial public offering becoming a listed company after listing on the Shanghai Stock Exchange STAR Market. The offering raised $540 million and the shares rose 64% on its trading debut.
In August 2024, it was reported that Hwatsing would invest $237.2 million to build a new plant in Shanghai.
In December 2024, Hwatsing was targeted in a new round of US export controls and added to the United States Department of Commerce's Entity List.
Business operations
Hwatsing's main product offerings are CMP machines. It has also expanded into other business lines such as grinders and wafer regeneration.
Hwatsing has been touted to break the monopoly of Applied Materials in China. Clients of Hwatsing include Semiconductor Manufacturing International Corporation, Hua Hong Semiconductor and Yangtze Memory Technologies.
See also
Chemical-mechanical polishing
Tsinghua Holdings
Semiconductor industry in China
References
External links
Tsinghua University
2013 establishments in China
2022 initial public offerings
Companies based in Tianjin
Companies listed on the Shanghai Stock Exchange
Electronics companies established in 2013
Equipment semiconductor companies
Government-owned companies of China
Semiconductor companies of China | Hwatsing Technology | [
"Engineering"
] | 353 | [
"Equipment semiconductor companies",
"Semiconductor fabrication equipment"
] |
78,154,172 | https://en.wikipedia.org/wiki/Bersacapavir | Bersacapavir is an experimental drug for the treatment of hepatitis B. It prevents hepatitis B virus (HBV) from replicating by inhibiting the formation of its capsid. It is also being studied for use in combination with JNJ-73763989, a small interfering RNA that targets HBV RNAs.
It can be synthesized beginning with N-methylpyrrole.
References
Experimental antiviral drugs
Nitriles
Pyrroles
Sulfonamides
Trifluoromethyl compounds
Fluoroarenes
Anilides | Bersacapavir | [
"Chemistry"
] | 117 | [
"Nitriles",
"Functional groups"
] |
78,155,640 | https://en.wikipedia.org/wiki/C11H15N5O5 | {{DISPLAYTITLE:C11H15N5O5}}
The molecular formula C11H15N5O5 (molar mass: 298.28 g/mol) may refer to:
7-Methylguanosine
Nelarabine | C11H15N5O5 | [
"Chemistry"
] | 56 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
78,155,708 | https://en.wikipedia.org/wiki/Feelie | A feelie is a physical item included to supplement a video game. Likely deriving their name from the fictional media in Aldous Huxley's 1932 novel Brave New World, feelies were popularized by the American video game company Infocom in the 1980s and subsequently adopted by such companies as Origin Systems and Sierra Entertainment in the United States and Namco and ASCII in Japan. Becoming less prevalent since the rise of digital distribution, feelies are now limited primarily to deluxe editions that are sold at a premium.
Feelies may take various forms, with common ones including reproductions of game objects, printed materials, cosmetics, and figurines. Historically, feelies allowed video game developers to implement copy protection and minimize the amount of digital space used for supplemental materials while simultaneously distinguishing their products from those of competitors. For players, feelies could provide assistance during gameplay, opportunities for continued play elsewhere, and improved immersion. Scholars have explored feelies as paratexts, while video game journalists have recalled them fondly.
Definition
The word "feelie" was used by the video game company Infocom to refer to the physical items packaged with its games. It had previously been used to describe a form of entertainment that also stimulates the senses of touch and smell by Aldous Huxley in his novel Brave New World (1932), which likely provides the etymology. In a 2013 interview, Infocom founder Dave Lebling recalled the team as having drawn inspiration from the board games of Dennis Wheatley, which had included dossiers, interviews, and even locks of hair.
Common feelies include reproductions of objects from games, printed materials (such as comic books and novels), and cosmetics for game controllers. Some feelies are integrated into game packaging; the packaging itself may also constitute a feelie. Figurines are common feelies in deluxe editions, and may assume a static pose or come with articulated joints that allow for play. Other recorded feelies have included tissues and dry pasta (Infogrames' Murders in Venice, 1989), as well as a cotton ball and a plastic bag said to contain a "microscopic space fleet" (Infocom's The Hitchhiker's Guide to the Galaxy, 1984).
The video game scholar Ian Peters divides feelies into two categories, artefacts and collectibles. He defines artefacts as objects that "seem to have been yanked from the immaterial world into the material one", thereby providing players with a tangible link to the game world. Collectibles, meanwhile, are understood as generally scaled-down objects that represent elements of the game world without being offered as examples of items contained therein.
Uses
For companies
In many games, feelies were historically used as a means of copy protection. By associating puzzle solutions with physical items, game developers disincentivized the distribution of bootleg copies; without the accompanying feelies, players could not complete the game. Examples include Lucasfilm Games' The Secret of Monkey Island (1990), which locked solutions behind a "Dial-a-Pirate" wheel, and Infocom's Return to Zork (1993), which came with an Encyclopaedia Frobozzica answering in-game questions. Such an approach, according to Lebling, was attractive in the 1980s due to the difficulty of using on-disc protection.
Infocom developer Steve Meretzky notes that, in the early years of video gaming when limited space was available for interactive digital media, feelies benefitted the production team by freeing space for other content. Remembering the production of Deadline (1982), Lebling contrasted the game with detective stories. Where novels had space for pages of exposition, such space was not available in contemporary media, and thus the Infocom team had developed a dossier to provide players with the necessary context and information to play the game.
As marketing material, feelies create a sense of added value, giving the impression that games are luxury items. Such upselling has become particularly commonplace with the practice of issuing deluxe editions of video games that contain the games themselves as well as supplemental materials. These special editions, partly due to the size of the figurines and other merchandise contained therein, have distinctive packaging that distinguishes them from other games. After purchase, such packaging may be displayed as artwork.
For players
Feelies have commonly served as extensions of games, allowing for play outside the video game world. Some game packages, especially in the 1980s, advised players as to potential uses for the feelies contained therein. Others have not included such information, allowing players to make their own interpretations.
Some feelies provide players with information that could be used to solve puzzles during gameplay, as in Infocom's Deadline and Cutthroats (1984). Other feelies are used to provide general guidance, such as the cloth maps included with Sierra Entertainment's Ultima II: The Revenge of the Enchantress (1982) and subsequent instalments. Some, such as the pin included with The Hitchhiker's Guide to the Galaxy (1984), offer accessories with which players can indicate their interests to others.
Feelies can also contribute to player immersion. This is achieved, in part, through their contribution to worldbuilding. The Witness (1983), for instance, included the fictitious magazine National Detective Gazette as well as a modified copy of the Santa Ana Register, thereby introducing players to game characters as well as the general context of 1930s California. Similarly, Deadline practised worldbuilding through a series of documents that players were instructed to read before beginning the game. Art books and behind-the-scenes videos are sometimes included with collectors' editions, providing insight into the production process.
Feelies provide a physical object that can stimulate the sense of touch even as the other senses are occupied elsewhere. Some feelies, such as the brochure for the Famous Adventurer's Correspondence School (FACS) that was packaged with Sierra Entertainment's Quest for Glory: So You Want to Be a Hero (1989), explicitly identify the player as a potential hero, thereby drawing them into the narrative. Others, such as the Goku wig included with Dragon Ball Z: For Kinect (2012), invited players to dress as game characters. Such feelies may be used for role-playing purposes.
History
Infocom and early feelies
Early video games were released as physical objects, with their packaging commonly considered ephemera. The American company Infocom, established in 1979, used the packaging of its early games as part of its marketing efforts; Starcross (1982), for instance, was packaged in a flying saucer. Other games were accompanied by large items reflective of their themes, such as the mask that came with Suspended (1983). Games published by Infocom after 1984 tended to use standardized packaging, but continued to include physical supplements. Deadline (1982) was the first Infocom game to include such materials.
Infocom's American competitors Origin Systems and Sierra Entertainment also began to include physical items with their releases in the 1980s, including the headband shipped with Origin's Moebius: The Orb of Celestial Harmony (1985) and the FACS brochure shipped with Sierra's Quest for Glory. Japanese companies also began to ship physical goods with their releases. For (1987), Namco produced a decoder for the game's runes, while ASCII shipped its strategy game Fleet Commander (1988) alongside a map and miniature ships with which players could track fleet movements.
Such feelies increased the production cost of games, at times resulting in tension between developers and publishing teams. Regarding the Ultima series, Origin vice-president Dallas Snell recalled that developer Richard Garriott would argue for high quality feelies with every instalment, despite the financial burden imposed on the company; conversely, the publishing team would suggest using paper instead of cloth and plastic instead of metal. Lebling considered the cost factor the main reason for Activision abandoning feelies after it acquired Infocom.
Feelies and deluxe editions
Following the advent of the CD-Rom in the 1990s, some forms of feelie began to be replaced with digital versions. Supplemental written materials, for example, were offered as emails and websites for In Memoriam (2003). Elsewhere, deluxe editions of video games were produced that shipped with physical objects. Examples include Spectrum HoloByte's Star Trek: The Next Generation – A Final Unity (1995), which came with a poster and an LCD pin depicting the USS Enterprise, and Vicious Cycle Software's Robotech: Battlecry (2002), which shipped with an art book, dog tags, a t-shirt, and the game's soundtrack.
Since the 2010s, digitally distributed video games have become more prevalent than physical releases. Where physical copies of games are released, they generally have limited supplemental materials. Most feelies are included in deluxe editions of video games. Compared to the feelies produced by Infocom and its contemporaries, these objects are generally of higher material quality. The game boxes may be shaped like in-game objects, such as the batarang case used for the deluxe edition of Rocksteady Studios's Batman: Arkham Asylum (2009). Some releases contain special steel cases for the games contained therein.
Other approaches to integrating video game content with merchandise have also been adopted. Some games, such as the Webkinz series, allowed players to include their real-world purchases stuffed animals in case of Webkinz into video games. Others, such as Mass Effect 3 (2012), included codes for downloadable content with merchandise and figurines. The video games scholar Carly Kocurek writes that, although these items are not identified as feelies, they "all fit the general purpose" by integrating merchandise and gameplay. Merchandise may also be offered as a pre-order bonus.
Some companies, such as Limited Run Games (LRG), have developed a business model of publishing physical releases of games, both standard and deluxe editions, with limited production runs. These are sold at a higher price than digital releases and may include a range of feelies; for instance, LRG's re-release of Digital Pictures' Night Trap (1992) was issued with a manual, fold-out poster, cassette tape, and embroidered patch. Others have sought to develop feelies to complement video games released elsewhere. The since-closed website feelies.org, for instance, produced physical items to accompany works of interactive fiction by writers such as Neil deMause, Emily Short, Stephen Granade, and Robb Sherwin.
Analysis and reception
Kocurek argues that, rather than be considered ephemera, feelies particularly those included with games by default served as "physical artefacts of a cultural form we too often think of as entirely digital" and were integrated into games' narratives. Consequently, such materials should be preserved as paratextual elements of the game. Peters argues that feelies offer insight into the concept of play, and research into the subject which he characterizes as lacking would allow for a better understanding of the texts they generate. This, he suggests, is particularly important as emulation is incapable of recreating the use of feelies in original game releases.
The feelies shipped with deluxe editions, Peters argues, may be understood as signifying the achievements of their owners. Such objects are ascribed a rarity and expense that, among video game collectors, is viewed positively. Indeed, the cases included with deluxe editions may be used as display objects, and various feelies including figurines and props are designed for a similar purpose.
Video game journalists have expressed fondness for feelies. Writing for PC Gamer, Andy Chalk described them as bringing games "to life in ways that digital just can't replicate." Adam Rosenberg, writing for Digital Trends, recalled the feelies of the 1980s with fondness, describing them as his biggest attraction when purchasing Bureaucracy (1987). In Rock, Paper, Shotgun, Alice O'Connor recalled that "feelies especially could blur the edges of reality and draw the world close around you", considering them potentially one of the best parts of gaming. Writing in the magazine Eye, Tom Hartshorn described feelies as creating "a layer of joyous interaction between the world we inhabit and the digital worlds we were tentatively exploring", thereby increasing players' emotional investment.
See also
Explanatory notes
References
Works cited
Video game accessories
Promotion and marketing communications
Video game marketing | Feelie | [
"Technology"
] | 2,534 | [
"Video game accessories",
"Components"
] |
67,980,941 | https://en.wikipedia.org/wiki/Coordination%20sequence | In crystallography and the theory of infinite vertex-transitive graphs, the coordination sequence of a vertex is an integer sequence that counts how many vertices are at each possible distance from . That is, it is a sequence
where each is the number of vertices that are steps away from . If the graph is vertex-transitive, then the sequence is an invariant of the graph that does not depend on the specific choice of . Coordination sequences can also be defined for sphere packings, by using either the contact graph of the spheres or the Delaunay triangulation of their centers, but these two choices may give rise to different sequences.
As an example, in a square grid, for each positive integer , there are grid points that are steps away from the origin. Therefore, the coordination sequence of the square grid is the sequence
in which, except for the initial value of one, each number is a multiple of four.
The concept was proposed by Georg O. Brunner and Fritz Laves and later developed by Michael O'Keefe. The coordination sequences of many low-dimensional lattices and uniform tilings are known.
The coordination sequences of periodic structures are known to be quasi-polynomial.
References
Crystallography
Infinite graphs
Integer sequences | Coordination sequence | [
"Physics",
"Chemistry",
"Materials_science",
"Mathematics",
"Engineering"
] | 251 | [
"Sequences and series",
"Integer sequences",
"Mathematical structures",
"Recreational mathematics",
"Mathematical objects",
"Infinity",
"Infinite graphs",
"Combinatorics",
"Materials science",
"Crystallography",
"Condensed matter physics",
"Numbers",
"Number theory"
] |
67,981,364 | https://en.wikipedia.org/wiki/Redheffer%20star%20product | In mathematics, the Redheffer star product is a binary operation on linear operators that arises in connection to solving coupled systems of linear equations. It was introduced by Raymond Redheffer in 1959, and has subsequently been widely adopted in computational methods for scattering matrices. Given two scattering matrices from different linear scatterers, the Redheffer star product yields the combined scattering matrix produced when some or all of the output channels of one scatterer are connected to inputs of another scatterer.
Definition
Suppose are the block matrices
and
,
whose blocks have the same shape when
.
The Redheffer star product is then defined by:
,
assuming that are invertible,
where is an identity matrix conformable
to or , respectively.
This can be rewritten several ways making use of the so-called
push-through identity
.
Redheffer's definition extends beyond matrices to
linear operators on a Hilbert space .
.
By definition, are linear endomorphisms of ,
making linear endomorphisms of ,
where is the direct sum.
However, the star product still makes sense as long as the transformations are compatible,
which is possible when
and
so that .
Properties
Existence
exists if and only if
exists.
Thus when either exists, so does the Redheffer star product.
Identity
The star identity is the identity on ,
or .
Associativity
The star product is associative, provided all of the relevant matrices are defined.
Thus .
Adjoint
Provided either side exists, the adjoint of a Redheffer
star product is .
Inverse
If is the left matrix inverse of such that
, has a right inverse, and
exists, then .
Similarly, if is the left matrix inverse of such
that , has a right inverse, and
exists, then .
Also, if and has a left inverse
then .
The star inverse equals the matrix inverse and both can be computed with
block inversion as
.
Derivation from a linear system
The star product arises from solving multiple linear systems of equations that share
variables in common.
Often, each linear system models the behavior of one subsystem in a physical process
and by connecting the multiple subsystems into a whole, one can eliminate variables
shared across subsystems in order to obtain the overall linear system.
For instance, let be elements of a Hilbert space
such that
and
giving the following equations in variables:
.
By substituting the first equation into the last we find:
.
By substituting the last equation into the first we find:
.
Eliminating by substituting the two preceding equations
into those for results in the Redheffer star product
being the matrix such that:
.
Connection to scattering matrices
Many scattering processes take on a form that motivates a different
convention for the block structure of the linear system of a scattering matrix.
Typically a physical device that performs a linear transformation on inputs, such as
linear dielectric media on electromagnetic waves or in quantum mechanical scattering,
can be encapsulated as a system which interacts with the environment through various
ports, each of which accepts inputs and returns outputs. It is conventional to use a different notation for the Hilbert space, , whose subscript
labels a port on the device.
Additionally, any element, , has an additional superscript labeling the direction of travel (where + indicates moving from port i to i+1 and - indicates the reverse).
The equivalent notation for a Redheffer transformation,
,
used in the previous section is
.
The action of the S-matrix,
,
is defined with an additional flip compared to Redheffer's definition:
,
so
.
Note that for in order for the off-diagonal identity matrices to be defined,
we require be the same underlying Hilbert space.
(The subscript does not imply any difference, but is just a label for bookkeeping.)
The star product, ,
for two S-matrices, , is given by
,
where
and ,
so .
Properties
These are analogues of the properties of for
Most of them follow from the correspondence
.
, the exchange operator, is also the S-matrix star identity defined below.
For the rest of this section, are S-matrices.
Existence
exists when either
or
exist.
Identity
The S-matrix star identity, , is
.
This means
Associativity
Associativity of follows from associativity of and of matrix multiplication.
Adjoint
From the correspondence between and ,
and the adjoint of , we have that
Inverse
The matrix that is the S-matrix star product inverse of
in the sense that
is where is the ordinary matrix inverse
and is as defined above.
Connection to transfer matrices
Observe that a scattering matrix can be rewritten as a
transfer matrix, , with action
,
where
.
Here the subscripts relate the different directions of propagation at each port.
As a result, the star product of scattering matrices
,
is analogous to the following matrix multiplication of transfer matrices
,
where
and ,
so .
Generalizations
Redheffer generalized the star product in several ways:
Arbitrary bijections
If there is a bijection given by
then an associative star product can be defined by:
.
The particular star product defined by Redheffer above is obtained from:
where .
3x3 star product
A star product can also be defined for 3x3 matrices.
Applications to scattering matrices
In physics, the Redheffer star product appears when constructing a total
scattering matrix from two or more subsystems.
If system has a scattering matrix and system
has scattering matrix , then the combined system
has scattering matrix .
Transmission line theory
Many physical processes, including radiative transfer, neutron diffusion, circuit theory, and others are described by scattering processes whose formulation depends on the dimension of the process and the representation of the operators. For probabilistic problems, the scattering equation may appear in a Kolmogorov-type equation.
Electromagnetism
The Redheffer star product can be used to solve for the propagation of electromagnetic fields in stratified, multilayered media. Each layer in the structure has its own scattering matrix and the total structure's scattering matrix can be described as the star product between all of the layers. A free software program that simulates electromagnetism in layered media is the
Stanford Stratified Structure Solver.
Semiconductor interfaces
Kinetic models of consecutive semiconductor interfaces can use a scattering matrix formulation to model the motion of electrons between the semiconductors.
Factorization on graphs
In the analysis of Schrödinger operators on graphs, the scattering matrix of a graph can be obtained as a generalized star product of the scattering matrices corresponding to its subgraphs.
References
Scattering theory
Scattering, absorption and radiative transfer
Hilbert spaces
Matrices
Mathematical physics | Redheffer star product | [
"Physics",
"Chemistry",
"Mathematics"
] | 1,340 | [
"Scattering theory",
" absorption and radiative transfer (optics)",
"Applied mathematics",
"Theoretical physics",
"Mathematical objects",
"Quantum mechanics",
"Matrices (mathematics)",
"Scattering",
"Hilbert spaces",
"Mathematical physics"
] |
67,982,033 | https://en.wikipedia.org/wiki/Romeo%20V.%20Turcan | Romeo V. Turcan (born 24 April 1970) is a professor at Aalborg University Business School. His research interests include creation and legitimation of new sectors and new organizations; Late-globalization, de-globalization, de-internationalization; Bubbles, collective behavior; High impact international entrepreneurship; and Cross-disciplinary theory building.
Education and career
Turcan holds a degree in mechanical engineering from the Air Force Engineering Military Academy, Riga, Latvia (1992) and in Philology from the Department of Post-University Studies, Moldova State University, Chișinău, Moldova (1995). In 2000, he received his MSc in International Marketing from the Department of Marketing, University of Strathclyde, Glasgow, United Kingdom; and in 2006, he received his PhD in International Entrepreneurship from the Hunter Centre for Entrepreneurship, University of Strathclyde.
Prior to commencing his academic career, Turcan worked in a range of posts involving public policy intervention in restructuring, rationalizing and modernizing business and public sectors such as power, oil, military high-tech, management consulting, information and communications technology (ICT) and higher education. In addition, he is the co-founder and former Executive Director of the International Association of Business and Parliament – Moldova.
He has also been a member of various boards including the board of Enterprise and Parliamentary Dialogue International, London, UK (2013-2019) and the board of The International Society of Markets and Development (2019-). He is chairman of the Organization of Moldovans in Denmark.
He is currently the project coordinator for the ERASMUS + Strategic Partnership project (2019-2023) and the H2020 Marie S. Curie project (2020-2024). In addition, he is the Founder and Coordinator of the Theory Building Research Program (2012-).
Honors
Since 2012, Turcan has been the main applicant and coordinator of four EU funded projects, incl., Marie S. Curie ITN, with a total value of more than 7.3 mil EUR:
"Legitimation of Newness and Its Impact on EU Agenda for Change", Marie S. Curie project (2020-2023, main applicant and coordinator)
"International Entrepreneurship Network for PhD and PhD Supervisor Training", Strategic Partnership (Erasmus+) project (2019-2022, main applicant and coordinator)
"PBLMD-TOPUP", ERASMUS+ Learning Mobility of Individuals (2017-2018, main applicant and coordinator)
"Introducing Problem Based Learning in Moldova: Toward Enhancing Students’ Competitiveness and Employability", ERASMUS+ Capacity Building national project (2015-2019, main applicant and coordinator)
"Enhancing University Autonomy in Moldova", ERASMUS+ Capacity Building structural project (2012-2015, main applicant and coordinator)
Publications
References
Academic staff of Aalborg University
People from Drochia District
1970 births
Living people
Moldovan engineers
Mechanical engineers | Romeo V. Turcan | [
"Engineering"
] | 586 | [
"Mechanical engineers",
"Mechanical engineering"
] |
67,983,082 | https://en.wikipedia.org/wiki/Pearl.com | Pearl.com is an "online paid question-and-answer service" based in San Francisco. "People aren't always willing to wait" in "legal, medical and other advice" led to "a growing number of those help-seekers are getting their guidance online."
History
Pearl.com began in 2003 as JustAnswer. Founder Andy Kurtzig had previously begun (and subsequently sold) a software company automating newspaper classifieds called Anser, a pun on his mother's ASK Group's name. The time period from attempting to obtaining funding until attaining significant revenue was described as "unusually long:" nine years. Once up and running, their offerings included traditionally high-priced fields such as law and medicine, but also "assistance from computer technicians and relationship counselors." By 2014, based on "the regulatory landscape involved" Pearl undertook to "overhaul" their expert teams.
Controversy
Regarding providing legal advice for "$30 to $40" and glossing over "details that could more easily emerge face to face" founder Andy Kurtzig conceded that an in-person followup may be needed. He said to The Wall Street Journal his service enables "to get key insights that will cut your appointment time from three hours to less than an hour.”
References
History of software | Pearl.com | [
"Technology"
] | 266 | [
"History of software",
"History of computing"
] |
67,983,178 | https://en.wikipedia.org/wiki/BIOTESC | BIOTESC (Biotechnology Space Support Center) is a space research centre working on behalf of the European Space Agency and attached to the Lucerne University of Applied Sciences and Arts (HSLU). BIOTESC is specialized in space research and biotechnologies:. On behalf of the European Space Agency, the centre offers assistance for the preparation, execution and post-flight analysis of many space experiments generally related to biotechnologies or information technologies.
History
BIOTESC is part of the Space Biology Group, founded in 1977 at the ETH Zurich. In January 2013, the group moved to Lucerne University. They relocated from Zurich to Hergiswil, where they moved into their own building. In 2018 they relocated in another place but stayed in the same city.
Payloads and Experiments
On board the International Space Station BIOTESC is responsible for several payloads in the European module Columbus: the CIMON robot, AstroPi computers, Kubik, an incubator for biological experiments, and the Biolab.
Several experiments on the ISS have been managed from the center as of 2021; including research on rotifer organisms and Arthrospira (Cyanobacterias)
BIOTESC is one of the several ESA User Support and Operations Centers (USOCs) in Europe.
References
Space research
European space programmes
European Space Agency | BIOTESC | [
"Engineering"
] | 273 | [
"Space programs",
"European space programmes"
] |
67,983,416 | https://en.wikipedia.org/wiki/Praseodymium%28III%29%20nitride | Praseodymium(III) nitride is a binary inorganic compound of praseodymium and nitrogen. Its chemical formula is . The compound forms black crystals, and reacts with water.
Preparation
Praseodymium(III) nitride can be prepared by the reaction of nitrogen and metallic praseodymium on heating:
It can also be prepared from the reaction of ammonia and praseodymium metal on heating:
Properties
Praseodymium(III) nitride forms black crystals of a cubic system. The space group is Fm3m, with cell parameter a = 0.5165 nm, Z = 4, its structure similar to that of sodium chloride (NaCl).
The compound is readily hydrolyzed with water and reacts with acids.
Applications
The compound is used in high-end electric and semiconductor products, and as a raw material to produce phosphor. Also it is used as a magnetic material and sputtering target material.
References
Nitrides
Praseodymium(III) compounds
Inorganic compounds
Rock salt crystal structure | Praseodymium(III) nitride | [
"Chemistry"
] | 223 | [
"Inorganic compounds"
] |
67,984,129 | https://en.wikipedia.org/wiki/Praseodymium%28IV%29%20fluoride | Praseodymium(IV) fluoride (also praseodymium tetrafluoride) is a binary inorganic compound, a highly oxidised metal salt of praseodymium and fluoride with the chemical formula PrF4.
Synthesis
Praseodymium(IV) fluoride can be prepared by the effect of krypton difluoride on praseodymium(IV) oxide:
Praseodymium(IV) fluoride can also be made by the dissolution of sodium hexafluoropraseodymate(IV) in liquid hydrogen fluoride:
Properties
Praseodymium(IV) fluoride forms light yellow crystals. The crystal structure is anticubic and isomorphic to that of uranium tetrafluoride UF4. It decomposes when heated:
Due to the high normal potential of the tetravalent praseodymium cations (Pr3+ / Pr4+: +3.2 V), praseodymium(IV) fluoride decomposes in water, releasing oxygen, O2.
See also
Praseodymium(III) fluoride
Uranium tetrafluoride
References
Fluorides
Praseodymium compounds
Inorganic compounds
Lanthanide halides | Praseodymium(IV) fluoride | [
"Chemistry"
] | 273 | [
"Fluorides",
"Inorganic compounds",
"Salts"
] |
67,984,176 | https://en.wikipedia.org/wiki/Shataranji | Shataranji () is a weaving technique traditionally used in the Rangpur region of Bangladesh. In 2021, it was declared a Geographical Indication Product of Bangladesh. It is used to produce carpets that are fashionable, artistic, and practical, especially when used as a blanket. Due to the expense involved in its production, Shataranji has historically been considered a symbol of aristocracy.
History
Shataranji is believed to date back to the Mughal Empire by locals, however, the exact origin of Shataranji is unknown. The weaving techniques are passed down from generation to generation among the same weaver families. In the 1830s, Ms. Nisbet, a British civil servant and then Collector of Rangpur, visited the village of Peerpur, nearby Rangpur. This led to his discovery of local villages where locals weaved using Shataranji. Impressed by the product, Nisbet used his government influence to promote it; the region was named Nisbetganj in his honor. During British rule, Shataranji carpets became commonplace throughout the Indian subcontinent, being exported to various locations in Sri Lanka, Burma, Indonesia, Thailand and Malaysia. After the Partition of India, Shataranji started losing popularity, nearly becoming extinct. It has seen a resurgence in the past few decades due to demand increase, the appreciation for handloom process and increased marketing.
Weaving style
Shataranji is a handloom process; no modern technology is used. The most common materials used to weave Shataranji are cotton yarn, jute yarn, wool, among others. Ropes made out of fibers are woven in geometrical patterns, typically measured by hand. During this process, specialized techniques and different colors are used to create unique geometrical patterns and designs. Designs represent the weaver's own expertise, techniques, and style, and typically draw on local traditions from northern India.
Typically, a Shataranji measures at least 30 x 20 inches, with the largest being 30 x 20 feet. A 6 x 9 foot carpet requires two workers to work for two full days, while a 1.5 x 3-foot carpet requires one weaver to work for 3 hours.
References
External links
Geographical indications in Bangladesh
Culture of Bangladesh
Floors
Bangladeshi handicrafts
Asian folk art
Culture of Bengal
Arts in Bangladesh
Bangladeshi art | Shataranji | [
"Engineering"
] | 470 | [
"Structural engineering",
"Floors"
] |
67,986,120 | https://en.wikipedia.org/wiki/HD%2026764 | HD 26764, also known as HR 1314 or rarely 14 H. Camelopardalis, is a solitary white hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.19, making it faintly to the naked eye if viewed under good conditions. Gaia DR3 parallax measurements place the object at a distance of 266 light years and is drifting closer with a poorly constrained heliocentric radial velocity of . At its current distance, HD 26764's brightness is diminished by 0.26 magnitudes due to interstellar dust.
HD 26764 has a stellar classification of either A2 Vn or A1 Vn. Both classes indicate that the object is an A-type main-sequence star with broad (nebulous) absorption lines due to rapid rotation. At present it has 2.74 times the mass of the Sun and 3.4 times the Sun's radius. It radiates 94 times the luminosity of the Sun from its photosphere at an effective temperature of . At the age of 388 million years, HD 26764 is a rather evolved dwarf star, having completed 91.2% of its main sequence lifetime. Like many hot stars, it spins rapidly with a projected rotational velocity of . An X-ray emission with a luminosity of has been detected around the star. A-type stars are not expected to produce X-rays, so it must be coming from an unseen companion.
References
A-type main-sequence stars
1314
019949
026764
Camelopardalis
Durchmusterung objects | HD 26764 | [
"Astronomy"
] | 333 | [
"Camelopardalis",
"Constellations"
] |
67,987,267 | https://en.wikipedia.org/wiki/The%20Equidistribution%20of%20Lattice%20Shapes%20of%20Rings%20of%20Integers%20of%20Cubic%2C%20Quartic%2C%20and%20Quintic%20Number%20Fields | The Equidistribution of Lattice Shapes of Rings of Integers of Cubic, Quartic, and Quintic Number Fields: An Artist's Rendering is a mathematics book by Piper Harron (also known as Piper H and Piper Harris), based on her Princeton University doctoral thesis of the same title. It has been described as "feminist", "unique", "honest", "generous", and "refreshing".
Thesis and reception
Harron was advised by Fields Medalist Manjul Bhargava, and her thesis deals with the properties of number fields, specifically the shape of their rings of integers. Harron and Bhargava showed that, viewed as a lattice in real vector space, the ring of integers of a random number field does not have any special symmetries. Rather than simply presenting the proof, Harron intended for the thesis and book to explain both the mathematics and the process (and struggle) that was required to reach this result.
The writing is accessible and informal, and the book features sections targeting three different audiences: laypeople, people with general mathematical knowledge, and experts in number theory. Harron intentionally departs from the typical academic format as she is writing for a community of mathematicians who "do not feel that they are encouraged to be themselves". Unusually for a mathematics thesis, Harron intersperses her rigorous analysis and proofs with cartoons, poetry, pop-culture references, and humorous diagrams. Science writer Evelyn Lamb, in Scientific American, expresses admiration for Harron for explaining the process behind the mathematics in a way that is accessible to non-mathematicians, especially "because as a woman of color, she could pay a higher price for doing it." Mathematician Philip Ording calls her approach to communicating mathematical abstractions "generous".
Her thesis went viral in late 2015, especially within the mathematical community, in part because of the prologue which begins by stating that "respected research math is dominated by men of a certain attitude". Harron had left academia for several years, later saying that she found the atmosphere oppressive and herself miserable and verging on failure. She returned determined that, even if she did not do math the "right way", she "could still contribute to the community". Her prologue states that the community lacks diversity and discourages diversity of thought. "It is not my place to make the system comfortable with itself", she concludes.
A concise proof was published in Compositio Mathematica in 2016.
Author
Harron earned her doctorate from Princeton in 2016. In the academic year 2023-2024 she was a teacher at Philips Exeter Academy. She has changed her name to Piper Harris. In 2017 in an American Mathematical Society blog she asked white cisgender men to leave their job, because they are "taking up room that should go to someone else".
References
External links
The Equidistribution of Lattice Shapes of Rings of Integers of Cubic, Quartic, and Quintic Number Fields (Harron's PhD thesis)
The Liberated Mathematician
AMS.Blogs
2021 non-fiction books
English-language non-fiction books
Birkhäuser books
Feminist books
Literature by African-American women
Mathematical proofs
Mathematics books
Theses | The Equidistribution of Lattice Shapes of Rings of Integers of Cubic, Quartic, and Quintic Number Fields | [
"Mathematics"
] | 669 | [
"nan"
] |
67,989,719 | https://en.wikipedia.org/wiki/Crohns%20MAP%20Vaccine | The Crohns MAP Vaccine is an experimental Viral vector vaccine intended to prevent or treat Crohn's disease, by provoking an immune response to one possible causative agent of the disease, Mycobacterium avium subsp. paratuberculosis. The vaccine is currently about to begin Phase 2 of its development. One of the scientists involved with this research is Thomas Borody, known for his work in developing the 'Triple Therapy' for treating ulcers caused by Helicobacter pylori.
References
Vaccines | Crohns MAP Vaccine | [
"Biology"
] | 115 | [
"Vaccination",
"Vaccines"
] |
67,991,589 | https://en.wikipedia.org/wiki/Zden%C4%9Bk%20Hedrl%C3%ADn | Zdeněk Hedrlín (1933 – April 22, 2018) was a Czech mathematician, specializing in universal algebra and combinatorial theory, both in pure and applied mathematics.
Zdeněk Hedrlín received his PhD from Prague's Charles University in 1963. His thesis on commutative semigroups was supervised by Miroslav Katětov. Hedrlín held the title of Docent (associated professor) at Charles University. There he worked at the Faculty of Mathematics and Physics for over 60 years until he died at age 85. He was among the first Czech mathematicians to do research on category theory.
In 1970 Hedrlín was an Invited Speaker at the International Congress of Mathematicians in Nice. In the later part of his career, he focused on applications of relational structures and led very successful special and interdisciplinary seminars. Applications to biological cell behavior earned him and his students a European grant. (He and his students worked on computational cell models of cancer.)
Hedrlín was a member of the editorial board of the Journal of Pure and Applied Algebra. His Erdős number is 1. His doctoral students include Vojtěch Rödl.
Selected publication
(over 160 citations)
References
20th-century Czech mathematicians
21st-century Czech mathematicians
Czech mathematicians
Category theorists
Combinatorialists
Charles University alumni
Academic staff of Charles University
1933 births
2018 deaths | Zdeněk Hedrlín | [
"Mathematics"
] | 269 | [
"Mathematical structures",
"Combinatorics",
"Combinatorialists",
"Category theory",
"Category theorists"
] |
66,465,134 | https://en.wikipedia.org/wiki/Fragilariforma | Fragilariforma is a genus of diatoms belonging to the family Fragilariaceae.
The genus was first described by D. M. Williams and Round in 1988.
The genus has cosmopolitan distribution.
Species:
Fragilariforma bicapitata
Fragilariforma neoproducta
Fragilariforma virescens
Fragilariforma virescens
References
Diatoms
Diatom genera | Fragilariforma | [
"Biology"
] | 88 | [
"Diatoms",
"Algae"
] |
66,467,002 | https://en.wikipedia.org/wiki/June%202123%20lunar%20eclipse | A total lunar eclipse will occur at the Moon’s ascending node of orbit on Wednesday, June 9, 2123, with an umbral magnitude of 1.7488. It will be a central lunar eclipse, in which part of the Moon will pass through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 1.4 days after apogee (on June 7, 2123, at 19:20 UTC), the Moon's apparent diameter will be smaller.
This dramatic total eclipse, lasting 106 minutes and 6 seconds, will plunge the full Moon into deep darkness as it passes right through the center of the Earth's umbral shadow. While the visual effect of a total eclipse is variable, the Moon may be stained a deep orange or red colour at maximum eclipse. This will be a great spectacle for everyone who sees it. The partial eclipse will last for 3 hours and 56 minutes in total. The penumbral eclipse lasts for 6 hours and 14 minutes. This will be the longest total lunar eclipse since July 16, 2000 (106 minutes, 25 seconds), and the longest one until May 12, 2264 (106 minutes, 13 seconds) and July 27, 3107 (106 minutes, 21 seconds), though the eclipse on June 19, 2141 will be nearly identical in all aspects. This will also be the longest of the 22nd century and the second longest of the 3rd millennium. The eclipse on June 19, 2141 will be the second longest of the 22nd century and the third longest of the third millennium (at 106 minutes 5 seconds).
Visibility
The eclipse will be completely visible over eastern and central North America, South America, and Antarctica, seen rising over western North America, eastern Australia, and the central Pacific Ocean and setting over Europe, Africa, and the Middle East.
Eclipse details
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
Eclipse season
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight. The first and last eclipse in this sequence is separated by one synodic month.
Related eclipses
Eclipses in 2123
A partial solar eclipse on May 25.
A total lunar eclipse on June 9.
A partial solar eclipse on June 23.
A partial solar eclipse on November 18.
A total lunar eclipse on December 3.
Metonic
Preceded by: Lunar eclipse of August 20, 2119
Followed by: Lunar eclipse of March 28, 2127
Tzolkinex
Preceded by: Lunar eclipse of April 27, 2116
Followed by: Lunar eclipse of July 21, 2130
Half-Saros
Preceded by: Solar eclipse of June 3, 2114
Followed by: Solar eclipse of June 13, 2132
Tritos
Preceded by: Lunar eclipse of July 9, 2112
Followed by: Lunar eclipse of May 8, 2134
Lunar Saros 132
Preceded by: Lunar eclipse of May 28, 2105
Followed by: Lunar eclipse of June 19, 2141
Inex
Preceded by: Lunar eclipse of June 28, 2094
Followed by: Lunar eclipse of May 18, 2152
Triad
Preceded by: Lunar eclipse of August 7, 2036
Followed by: Lunar eclipse of April 10, 2210
Lunar eclipses of 2121–2125
This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.
The penumbral lunar eclipses on February 2, 2121 and July 30, 2121 occur in the previous lunar year eclipse set, and the penumbral lunar eclipses on April 18, 2125 and October 12, 2125 occur in the next lunar year eclipse set.
Saros 132
Tritos series
Half-Saros cycle
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros). This lunar eclipse is related to two total solar eclipses of Solar Saros 139.
References
2123-06
2123-06
2123-06 | June 2123 lunar eclipse | [
"Astronomy"
] | 1,016 | [
"Future astronomical events",
"Future lunar eclipses"
] |
66,467,501 | https://en.wikipedia.org/wiki/Phylogenetic%20Assignment%20of%20Named%20Global%20Outbreak%20Lineages | The Phylogenetic Assignment of Named Global Outbreak Lineages (PANGOLIN) is a software tool developed by Dr. Áine O'Toole and members of the Andrew Rambaut laboratory, with an associated web application developed by the Centre for Genomic Pathogen Surveillance in South Cambridgeshire. Its purpose is to implement a dynamic nomenclature (known as the Pango nomenclature) to classify genetic lineages for SARS-CoV-2, the virus that causes COVID-19. A user with a full genome sequence of a sample of SARS-CoV-2 can use the tool to submit that sequence, which is then compared with other genome sequences, and assigned the most likely lineage (Pango lineage). Single or multiple runs are possible, and the tool can return further information regarding the known history of the assigned lineage. Additionally, it interfaces with Microreact, to show a time sequence of the location of reports of sequenced samples of the same lineage. This latter feature draws on publicly available genomes obtained from the COVID-19 Genomics UK Consortium and from those submitted to GISAID. It is named after the pangolin.
Context
PANGOLIN is a key component underpinning the Pango nomenclature system.
As described in Andrew Rambaut et al. (2020), a Pango lineage is described as a cluster of sequences that are associated with an epidemiological event, for instance an introduction of the virus into a distinct geographic area with evidence of onward spread. Lineages are designed to capture the emerging edge of the pandemic and are at a fine-grain resolution suitable to genomic epidemiological surveillance and outbreak investigation.
Both the tool and the PANGOLIN nomenclature system have been used extensively during the COVID-19 pandemic.
Description
Lineage designation
Distinct from the PANGOLIN tool, Pango lineages are regularly, manually curated based on the current globally circulating diversity. A large phylogenetic tree is constructed from an alignment containing publicly available SARS-CoV-2 genomes, and sub-clusters of sequences in this tree are manually examined and cross-referenced against epidemiological information to designate new lineages; these can be designated by data producers, and lineage suggestions can be submitted to the Pango team via a GitHub issue request.
Model training
These manually curated lineage designations, and the associated genome sequences, are the input into the machine learning model training. This model, both the training and the assignment, has been termed 'pangoLEARN'. The current version of pangoLEARN uses a classification tree, based on the scikit-learn implementation of a decision tree classifier.
Lineage assignation
Originally, PANGOLIN used a maximum-likelihood-based assignment algorithm to assign query SARS-CoV-2 the most likely lineage sequence. Since the release of Version 2.0 in July 2020, however, it has used the 'pangoLEARN' machine-learning-based assignment algorithm to assign lineages to new SARS-CoV-2 genomes. This approach is fast and can assign large numbers of SARS-CoV-2 genomes in a relatively short time.
Availability
PANGOLIN is available as a command-line-based tool, downloadable from Conda and from a GitHub repository, and as a web-application with a drag-and-drop graphical user interface. The PANGOLIN web application has assigned more than 512,000 unique SARS-CoV-2 sequences as of January 2021.
Creators and developers
PANGOLIN was created by Áine O'Toole and the Rambaut lab and released on 5 April 2020. The main developers of PANGOLIN are Áine O'Toole and Emily Scher; many others have contributed to various aspects of the tool, including Ben Jackson, J.T. McCrone, Verity Hill, and Rachel Colquhoun of the Rambaut Lab.
The PANGOLIN web application was developed by the Centre for Genomic Pathogen Surveillance, namely Anthony Underwood, Ben Taylor, Corin Yeats, Khali Abu-Dahab, and David Aanensen.
See also
Colloquial names of COVID-19 variants
Variants of SARS-CoV-2
Nextstrain
INSDC
References
External links
pango.network — information on the Pango system rules, governance committee, and lineage designation committee
Phylogenetics software
Genome databases
Medical software
Medical responses to the COVID-19 pandemic | Phylogenetic Assignment of Named Global Outbreak Lineages | [
"Biology"
] | 902 | [
"Medical software",
"Medical technology"
] |
66,468,324 | https://en.wikipedia.org/wiki/Sparsity%20matroid | A sparsity matroid is a mathematical structure that captures how densely a multigraph is populated with edges. To unpack this a little, sparsity is a measure of density of a graph that bounds the number of edges in any subgraph. The property of having a particular matroid as its density measure is invariant under graph isomorphisms and so it is a graph invariant.
The graphs we are concerned with generalise simple directed graphs by allowing multiple same-oriented edges between pairs of vertices. Matroids are a quite general mathematical abstraction that describe the amount of indepdendence in, variously, points in geometric space and paths in a graph; when applied to characterising sparsity, matroids describe certain sets of sparse graphs. These matroids are connected to the structural rigidity of graphs and their ability to be decomposed into edge-disjoint spanning trees via the Tutte and Nash-Williams theorem. There is a family of efficient algorithms, known as pebble games, for determining if a multigraph meets the given sparsity condition.
Definitions
-sparse multigraph. A multigraph is -sparse, where and are non-negative integers, if for every subgraph of , we have .
-tight multigraph. A multigraph is -tight if it is -sparse and .
-sparse and tight multigraph. A multigraph is -sparse if there exists a subset such that the subgraph is -sparse and the subgraph is -sparse. The multigraph is -tight if, additionally, .
-sparsity matroid. The -sparsity matroid is a matroid whose ground set is the edge set of the complete multigraph on vertices, with loop multiplicity and edge multiplicity , and whose independent sets are -sparse multigraphs on vertices. The bases of the matroid are the -tight multigraphs and the circuits are the -sparse multigraphs that satisfy .
The first examples of sparsity matroids can be found in. Not all pairs induce a matroid.
Pairs (k,l) that form a matroid
The following result provides sufficient restrictions on for the existence of a matroid.
Theorem. The -sparse multigraphs on vertices are the independent sets of a matroid if
and ;
and ; or
or and .
Some consequences of this theorem are that -sparse multigraphs form a matroid while -sparse multigraphs do not. Hence, the bases, i.e., -tight multigraphs, must all have the same number of edges and can be constructed using techniques discussed below. On the other hand, without this matroidal structure, maximally -sparse multigraphs will have different numbers of edges, and it is interesting to identify the one with the maximum number of edges.
Connections to rigidity and decomposition
Structural rigidity is about determining if almost all, i.e. generic, embeddings of a (simple or multi) graph in some -dimensional metric space are rigid. More precisely, this theory gives combinatorial characterizations of such graphs. In Euclidean space, Maxwell showed that independence in a sparsity matroid is necessary for a graph to be generically rigid in any dimension.
Maxwell Direction. If a graph is generically minimally rigid in -dimensions, then it is independent in the -sparsity matroid.
The converse of this theorem was proved in -dimensions, yielding a complete combinatorial characterization of generically rigid graphs in . However, the converse is not true for , see combinatorial characterizations of generically rigid graphs.
Other sparsity matroids have been used to give combinatorial characterizations of generically rigid multigraphs for various types of frameworks, see rigidity for other types of frameworks. The following table summarizes these results by stating the type of generic rigid framework in a given dimension and the equivalent sparsity condition. Let be the multigraph obtained by duplicating the edges of a multigraph times.
The Tutte and Nash-Williams theorem shows that -tight graphs are equivalent to graphs that can be decomposed into edge-disjoint spanning trees, called -arborescences. A -arborescence is a multigraph such that adding edges to yields a -arborescence. For , a -sparse multigraph is a -arborescence; this was first shown for sparse graphs. Additionally, many of the rigidity and sparsity results above can be written in terms of edge-disjoint spanning trees.
Constructing sparse multigraphs
This section gives methods to construct various sparse multigraphs using operations defined in constructing generically rigid graphs. Since these operations are defined for a given dimension, let a -extension be a -dimensional -extension, i.e., a -extension where the new vertex is connected to distinct vertices. Likewise, a -extension is a -dimensional -extension.
General (k,l)-sparse multigraphs
The first construction is for -tight graphs. A generalized -extension is a triple , where edges are removed, for , and the new vertex is connected to the vertices of these edges and to distinct vertices. The usual -extension is a -extension.
Theorem. A multigraph is -tight if and only if it can be constructed from a single vertex via a sequence of - and -extensions.
This theorem was then extended to general -tight graphs. Consider another generalization of a -extension denoted by , for , where edges are removed, the new vertex is connected to the vertices of these edges, loops are added to , and is connected to other distinct vertices. Also, let denote a multigraph with a single node and loops.
Theorem. A multigraph is -tight for
if and only if can be constructed from via a sequence of -extensions, such that and ;
if and only if can be constructed from via a sequence of -extensions, such that and .
Neither of these constructions are sufficient when the graph is simple. The next results are for -sparse hypergraphs. A hypergraph is -uniform if each of its edges contains exactly vertices. First, conditions are established for the existence of -tight hypergraphs.
Theorem. There exists an such that for all , there exist -uniform hypergraphs on vertices that are -tight.
The next result extends the Tutte and Nash-Williams theorem to hypergraphs.
Theorem. If is a -tight hypergraph, for , then is a arborescence, where the added edges contain at least two vertices.
A map-hypergraph is a hypergraph that admits an orientation such that each vertex has an out-degree of . A -map-hypergraph is a map-hypergraph that can be decomposed into edge-disjoint map-hypergraphs.
Theorem. If is a -tight hypergraph, for , then is the union of an -arborescence and a -map-hypergraph.
(2,3)-sparse graphs
The first result shows that -tight graphs, i.e., generically minimally rigid graphs in have Henneberg-constructions.
Theorem. A graph is -tight if and only if it can be constructed from the complete graph via a sequence of - and -extensions.
The next result shows how to construct -circuits. In this setting, a -sum combines two graphs by identifying two subgraphs in each and then removing the combined edge from the resulting graph.
Theorem. A graph is a -circuit if and only if it can be constructed from disjoint copies of the complete graph via a sequence of -extensions within connected components and -sums of connected components.
The method for constructing -connected -circuits is even simpler.
Theorem. A graph is a -connected -circuit if and only if it can be constructed from the complete graph via a sequence of -extensions.
These circuits also have the following combinatorial property.
Theorem. If a graph is a -circuit that is not the complete graph , then has at least vertices of degree such that performing a -reduction on any one of these vertices yields another -circuit.
(2,2)-sparse graphs
The next results shows how to construct -circuits using two different construction methods. For the first method, the base graphs are shown in Figure 2 and the three join operations are shows in Figure 2. A -join identifies a subgraph in with an edge of a subgraph in , and removes the other two vertices of the . A -join identifies an edge of a subgraph in with an edge of a subgraph in , and removes the other vertices on both subgraphs. A -join takes a degree vertex in and a degree vertex in and removes them, then it adds edges between and such that there is a bijection between the neighbors of and .
The second method uses -dimensional vertex-splitting, defined in the constructing generically rigid graphs, and a vertex-to- operation, which replace a vertex of a graph with a graph and connects each neighbor of to any vertex of the .
Theorem. A graph is a -circuit if and only if
can be constructed from disjoint copies of the base graphs via a sequence of -extensions within connected components and -, -, and - sums of connected components;
can be constructed from via a sequence of - and -extensions, vertex-to-, and -dimensional vertex-splitting operations
(2,1)-sparse graphs
The following result gives a construction method for -tight graphs and extends the Tutte and Nash-Williams theorem to these graphs. For the construction, the base graphs are with an edge removed or the -sum of two graphs (the shared edge is not removed), see the middle graph in Figure 2. Also, an edge-joining operation adds a single edge between two graphs.
Theorem. A graph is -tight if and only if
can be obtained from with an edge removed or the -sum of two graphs via a sequence of - and -extensions, vertex-to-, -dimensional vertex-splitting, and edge-joining operations;
is the edge-disjoint union of a spanning tree and a spanning graph in which every connected component contains exactly one cycle.
Pebble games
There is a family of efficient network-flow based algorithms for identifying -sparse graphs, where . The first of these types of algorithms was for -sparse graphs. These algorithms are explained on the Pebble game page.
References
Graph invariants | Sparsity matroid | [
"Mathematics"
] | 2,104 | [
"Graph invariants",
"Mathematical relations",
"Graph theory"
] |
66,468,679 | https://en.wikipedia.org/wiki/Seega%20%28game%29 | Seega is an abstract strategy game that originated in Egypt. It can be played on boards with cells in a 5×5, 7×7 or 9×9 disposition. Other names include Seejeh, Siga and Sidjah.
The board starts out empty, and players take turns placing two pieces in any empty cell, excluding the center cell. Then, players move their pieces trying to bound their opponent's pieces to remove them.
The game has been described in literature since at least 1836.
Rules
The game is played by two players, one with dark pieces and the other with clear pieces. Both start with the same number of pieces, equal to half the number of cells in the board minus one cell. Therefore, if the board has 25 cells, each player starts with 12 pieces. If the board has 49 cells, each player starts with 24 pieces. Some Seega boards have an X in the center cell.
Similar to Yoté, the Seega board starts empty, and players may place their pieces in the cells of their own choice.
The game has two stages. In the first, the positioning stage, players place their pieces in the board cells, and cannot place any piece in the center cell. In each turn, each player places two pieces, until they have placed all their pieces.
In the second stage, the moving stage, players move their pieces and capture their opponent's pieces. The first move of player 1 must be moving a piece to the center of the board. Pieces can be moved horizontally or vertically, never diagonally, and cannot jump over other pieces.
To capture a piece, a player must move one of their pieces in such way as to "bound" an opponent piece in one way (either vertically or horizontally). That is, if moving a dark piece results in a clear piece having a dark piece to its right and to its left (that is, the piece that has just been moved and another one), the clear piece will be removed. Same thing happens if the clear piece has a dark piece below and above it. If a player places one of its pieces between two opponent's pieces, nothing happens: captures only occur when a player bounds the pieces of the opponent.
After capturing an opponent's piece, the player can move again if that results in another capture.
Variants
There are many rules that describe what happen if a player can not move a piece. In one variant, the player can skip their turn, and their opponent plays again. In another, the player that can't make a move can make their opponent remove a piece that will allow the player to make a move. In another one, the player that can't make a move loses the game, except if it happens immediately after the first move of player one. That is, if after player 1 moves for the first time leaving player 2 with no moves, player 1 must remove one of its pieces adjacent to the cell which the first piece moved came from, so that player 2 can move. In another variant, it is player 2 that chooses which piece from player 1 will be removed.
In some versions, the game is over when one player has only one piece left. In others, the game is only over when one player has lost their final piece.
History
The book An Account Of The Manners And Customs Of The Modern Egyptians (1st edition from 1836) by Edward William Lane mentions the game. According to him, the 5×5 board is called "khamsáwee seega", the 7×7 board is called "seb'áwee", and the 9×9 board is called "tisáwee". The first move of each player is predetermined, as described in the image. The board and game of Seega must not be confused with the board and game called "táb" (also called "Seega") which has four rows of nine to fifteen cells, and is also described by Lane.
Another mention of the game is from an 1890 paper published in the Journal of American Folklore. In the paper, H. Carrington Bolton says he was camping by Mount Sinai and saw Egyptians and bedouins playing in holes dug in the sand. Bolton describes variants with 5×5, 7×7 and 9×9 cells. According to him, the game was called "seegà", and the pieces "kelb".
See also
Polis (board game)
Senet
References
External links
Board games
Mathematical games
Culture of Egypt | Seega (game) | [
"Mathematics"
] | 911 | [
"Recreational mathematics",
"Mathematical games"
] |
66,468,809 | https://en.wikipedia.org/wiki/List%20of%20recipients%20of%20the%20St%20Peter%27s%20Medal | This is a list of recipients of the St Peter's Medal, the highest award of the British Association of Urological Surgeons (BAUS).
1949-1959
1960-1969
1970-1979
1980-1989
1990-1999
2000-2009
2010-2020
2021-2024
References
Urology
Medicine awards
Recipients of the St Peter's Medal | List of recipients of the St Peter's Medal | [
"Technology"
] | 70 | [
"Science and technology awards",
"Medicine awards"
] |
66,472,311 | https://en.wikipedia.org/wiki/Vanadium%20cycle | The global vanadium cycle is controlled by physical and chemical processes that drive the exchange of vanadium between its two main reservoirs: the upper continental crust and the ocean. Anthropogenic processes such as coal and petroleum production release vanadium to the atmosphere.
Sources
Natural sources
Vanadium is a trace metal that is relatively abundant in the Earth (~100 part per million in the upper crust). Vanadium is mobilized from minerals through weathering and transported to the ocean. Vanadium can enter the atmosphere through wind erosion and volcanic emissions and will remain there until it is removed by precipitation.
Anthropogenic sources
Human activity has increased the amount of vanadium emissions to the atmosphere. Vanadium is abundant in fossil fuels because it is incorporated in porphyrins during organic matter degradation. Coal and petroleum factory pollution release significant vanadium to the atmosphere. Vanadium is also mined and using for industrial purposes including for steel reinforcement, electronics, and batteries.
Sink
Vanadium is removed from the ocean by burial marine sediments and incorporation into iron oxides at hydrothermal vents.
Biological processes
Biological processes play a relatively minor role in the global vanadium cycle. Vanadium bromoperoxidase is present in some marine bacteria and algae. Vanadium can also takes the place of molybdenum in alternative nitrogenases.
References
Vanadium
Biogeochemical cycle | Vanadium cycle | [
"Chemistry"
] | 291 | [
"Biogeochemical cycle",
"Biogeochemistry"
] |
66,473,899 | https://en.wikipedia.org/wiki/Glonium | Glonium is a genus of fungi belonging to the family Gloniaceae.
The genus was first described by Gotthilf Heinrich Ernst Muhlenberg in 1813.
Species:
Glonium graphicum
Glonium lineare
References
Mytilinidiales | Glonium | [
"Biology"
] | 53 | [
"Fungus stubs",
"Fungi"
] |
66,474,041 | https://en.wikipedia.org/wiki/Supernova%20neutrinos | Supernova neutrinos are weakly interactive elementary particles produced during a core-collapse supernova explosion. A massive star collapses at the end of its life, emitting on the order of 1058 neutrinos and antineutrinos in all lepton flavors. The luminosity of different neutrino and antineutrino species are roughly the same. They carry away about 99% of the gravitational energy of the dying star as a burst lasting tens of seconds. The typical supernova neutrino energies are . Supernovae are considered the strongest and most frequent source of cosmic neutrinos in the MeV energy range.
Since neutrinos are generated in the core of a supernova, they play a crucial role in the star's collapse and explosion. Neutrino heating is believed to be a critical factor in supernova explosions. Therefore, observation of neutrinos from supernovae provides detailed information about core collapse and the explosion mechanism. Further, neutrinos undergoing collective flavor conversions in a supernova's dense interior offers opportunities to study neutrino-neutrino interactions. The only supernova neutrino event detected so far is SN 1987A. Nevertheless, with current detector sensitivities, it is expected that thousands of neutrino events from a galactic core-collapse supernova would be observed. The next generation of experiments are designed to be sensitive to neutrinos from supernova explosions as far as Andromeda or beyond. The observation of supernovae will broaden our understanding of various astrophysical and particle physics phenomena. Further, coincident detection of supernova neutrino in different experiments would provide an early alarm to astronomers about a supernova.
History
Stirling A. Colgate and Richard H. White, and independently W. David Arnett, identified the role of neutrinos in core collapse, which resulted in the subsequent development of the theory of supernova explosion mechanism. In February 1987, the observation of supernova neutrinos experimentally verified the theoretical relationship between neutrinos and supernovae. The Nobel Prize-winning event, known as SN 1987A, was the collapse of a blue supergiant star Sanduleak -69° 202, in the Large Magellanic Cloud outside our Galaxy, 51 kpc away. About lightweight weakly-interacting neutrinos were produced, carrying away almost all of the energy of the supernova. Two kiloton-scale water Cherenkov detectors, Kamiokande II and IMB, along with a smaller Baksan Observatory, detected a total of 25 neutrino-events over a period of about 13 seconds. Only electron-type neutrinos were detected because neutrino energies were below the threshold of muon or tau production. The SN 1987A neutrino data, although sparse, confirmed the salient features of the basic supernova model of gravitational collapse and associated neutrino emission. It put strong constraints on neutrino properties such as charge and decay rate. The observation is considered a breakthrough in the field of supernova and neutrino physics.
Properties
Neutrinos are fermions, i.e. elementary particles with a spin of 1/2. They interact only through weak interaction and gravity. A core-collapse supernova emits a burst of ~ neutrinos and antineutrinos on a time scale of tens of seconds. Supernova neutrinos carry away about 99% of the gravitational energy of the dying star in the form of kinetic energy. Energy is divided roughly equally between the three flavors of neutrinos and three flavors of antineutrinos. Their average energy is of the order 10 MeV. The neutrino luminosity of a supernova is typically on the order of or . The core-collapse events are the strongest and most frequent source of cosmic neutrinos in the MeV energy range.
During a supernova, neutrinos are produced in enormous numbers inside the core. Therefore, they have a fundamental influence on the collapse and supernova explosions. Neutrino heating is predicted to be responsible for the supernova explosion. Neutrino oscillations during the collapse and explosion generate the gravitational wave bursts. Furthermore, neutrino interactions set the neutron-to-proton ratio, determining the nucleosynthesis outcome of heavier elements in the neutrino driven wind.
Production
Supernova neutrinos are produced when a massive star collapses at the end of its life, ejecting its outer mantle in an explosion. Wilson's delayed neutrino explosion mechanism has been used for 30 years to explain core collapse supernova.
Near the end of life, a massive star is made up of onion-layered shells of elements with an iron core. During the early stage of the collapse, electron neutrinos are created through electron-capture on protons bound inside iron-nuclei:
The above reaction produces neutron-rich nuclei, leading to neutronization of the core. Therefore, this is known as the neutronization phase. Some of these nuclei undergo beta-decay and produce anti-electron neutrinos:
The above processes reduce the core energy and its lepton density. Hence, the electron degeneracy pressure is unable to stabilize the stellar core against the gravitational force, and the star collapses. When the density of the central region of collapse exceeds , the diffusion time of neutrinos exceeds the collapse time. Therefore, the neutrinos become trapped inside the core. When the central region of the core reaches nuclear densities (~ 1014 g/cm3), the nuclear pressure causes the collapse to deaccelerate. This generates a shock wave in the outer core (region of iron core), which triggers the supernova explosion. The trapped electron neutrinos are released in the form of neutrino burst in the first tens of milliseconds. It is found from simulations that the neutrino burst and iron photo-disintegration weaken the shock wave within milliseconds of propagation through the iron core. The weakening of the shock wave results in mass infall, which forms a neutron star. This is known as the accretion phase and lasts between few tens to few hundreds of milliseconds. The high-density region traps neutrinos. When the temperature reaches 10 MeV, thermal photons generate electron–positron pairs. Neutrinos and antineutrinos are created through weak-interaction of electron–positron pairs:
The luminosity of electron flavor is significantly higher than for non-electrons. As the neutrino temperature rises in the compressionally heated core, neutrinos energize the shock wave through charged current reactions with free nucleons:
When the thermal pressure created by neutrino heating increases above the pressure of the infalling material, the stalled shock wave is rejuvenated, and neutrinos are released. The neutron star cools down as the neutrino-pair production and neutrino release continues. Therefore, it is known as the cooling phase. The Luminosities of different neutrino and antineutrino species are roughly the same. The supernova neutrino luminosity drops significantly after several tens of seconds.
Oscillation
The knowledge of flux and flavor content of the neutrinos behind the shock wave is essential to implement the neutrino-driven heating mechanism in computer simulations of supernova explosions. Neutrino oscillations in dense matter is an active field of research.
Neutrinos undergo flavor conversions after they thermally decouple from the proto-neutron star. Within the neutrino-bulb model, neutrinos of all flavors decouple at a single sharp surface near the surface of the star. Also, the neutrinos travelling in different directions are assumed to travel the same path length in reaching a certain distance R from the center. This assumption is known as single angle approximation, which along with spherical symmetricity of the supernova, allows us to treat neutrinos emitted in the same flavor as an ensemble and describe their evolution only as a function of distance.
The flavor evolution of neutrinos for each energy mode is described by the density matrix:
Here, is the initial neutrino luminosity at the surface of a proto-neutron star which drops exponentially. Assuming decay time by , the total energy emitted per unit time for a particular flavor can be given by . represents average energy. Therefore, the fraction gives the number of neutrinos emitted per unit of time in that flavor. is normalized energy distribution for the corresponding flavor.
The same formula holds for antineutrinos too.
Neutrino luminosity is found by the following relation:
The integral is multiplied by 6 because the released binding energy is divided equally between the three flavors of neutrinos and three flavors of antineutrinos.
The evolution of the density operator is given by Liouville's equation:
The Hamiltonian covers vacuum oscillations, charged current interaction of neutrinos from electrons and protons, as well as neutrino–neutrino interactions. Neutrino self-interactions are non-linear effects that result in collective flavor conversions. They are significant only when interaction frequency exceeds vacuum oscillation frequency. Typically, they become negligible after a few hundred kilometers from the center. Thereafter, Mikheyev–Smirnov–Wolfenstein resonances with the matter in the stellar envelope can describe the neutrino evolution.
Detection
There are several different ways to observe supernova neutrinos. Almost all of them involves the inverse beta decay reaction for the detection of neutrinos. The reaction is a charged current weak interaction, where an electron antineutrino interacts with a proton produces a positron and a neutron:
The positron retains most of the energy of the incoming neutrino. It produces a cone of Cherenkov light, which is detected by photomultiplier tubes (PMT's) arrayed on the walls of the detector. Neutrino oscillations in the Earth matter may affect the supernova neutrino signals detected in experimental facilities.
With current detector sensitivities, it is expected that thousands of neutrino events from a galactic core-collapse supernova would be observed. Large-scale detectors such as Hyper-Kamiokande or IceCube can detect up to events. Unfortunately, SN 1987A is the only supernova neutrino event detected so far. There have not been any galactic supernova in the Milky Way in the last 120 years, despite the expected rate of 0.8-3 per century. Nevertheless, a supernova at 10 kPc distance will enable a detailed study of the neutrino signal, providing unique physics insights. Additionally, the next generation of underground experiments, like Hyper-Kamiokande, are designed to be sensitive to neutrinos from supernova explosions as far as Andromeda or beyond. Further they are speculated to have good supernova pointing capability too.
Significance
Since supernova neutrinos originate deep inside the stellar core, they are a relatively reliable messenger of the supernova mechanism. Due to their weakly interacting nature, the neutrino signals from a galactic supernova can give information about the physical conditions at the center of core collapse, which would be otherwise inaccessible. Furthermore, they are the only source of information for core-collapse events which don't result in a supernova or when the supernova is in a dust-obscured region. Future observations of supernova neutrinos will constrain the different theoretical models of core collapse and explosion mechanism, by testing them against the direct empirical information from the supernova core.
Due to their weakly interacting nature, near light speed neutrinos emerge promptly after the collapse. In contrast, there may be a delay of hours or days before the photon signal emerges from the stellar envelope. Therefore, a supernova will be observed in neutrino observatories before the optical signal, even after travelling millions of light years. The coincident detection of neutrino signals from different experiments would provide an early alarm to astronomers to direct telescopes to the right part of the sky to capture the supernova's light. The Supernova Early Warning System is a project which aims to connect neutrino detectors around the world, and trigger the electromagnetic counterpart experiments in case of a sudden influx of neutrinos in the detectors.
The flavor evolution of neutrinos, propagating through the dense and turbulent interior of the supernova, is dominated by the collective behavior associated with neutrino-neutrino interactions. Therefore, supernova neutrinos offer an opportunity to examine neutrino flavor mixing under high-density conditions. Being sensitive to neutrino mass ordering and mass hierarchy, they can provide information about neutrino properties. Further, they can act as a standard candle to measure cosmic distance as the neutronization burst signal does not depend on its progenitor.
Diffused supernova neutrino background
The Diffuse Supernova Neutrino Background (DSNB) is a cosmic background of (anti)neutrinos formed by the accumulation of neutrinos emitted from all past core-collapse supernovae. Their existence was predicted even before the observation of supernova neutrinos. DSNB can be used to study physics on the cosmological scale. They provide an independent test of the supernova rate. They can also give information about neutrino emission properties, stellar dynamics and failed progenitors. Super-Kamiokande has put the observational upper limit on the DSNB flux as above 19.3 MeV of neutrino energy. The theoretically estimated flux is only half this value. Therefore, the DSNB signal is expected to be detected in the near future with detectors like JUNO and SuperK-Gd.
Notes
References
Supernovae
Neutrino astronomy | Supernova neutrinos | [
"Chemistry",
"Astronomy"
] | 2,902 | [
"Supernovae",
"Neutrino astronomy",
"Astronomical events",
"Explosions",
"Astronomical sub-disciplines"
] |
66,476,391 | https://en.wikipedia.org/wiki/Lonicera%20%C3%97%20purpusii | Lonicera × purpusii, the Purpus honeysuckle, is a hybrid species of flowering plant in the family Caprifoliaceae. It originated as a cross of garden origin between two Chinese species, L. fragrantissima and L. standishii.
Growing to tall and broad, it is a somewhat untidy shrub with ovate leaves and small paired cream/yellow flowers in winter. The flowers are strongly fragrant with the typical honeysuckle scent. It is extremely hardy, tolerating temperatures down to and a wide range of conditions. In a favourable environment it may be evergreen but is otherwise deciduous. In the latter case, the flowers are borne on the bare branches.
The widely grown cultivar 'Winter Beauty' is a recipient of the Royal Horticultural Society's Award of Garden Merit. It flowers best in full sun.
References
purpusii
Hybrid plants
Plants described in 1923
Taxa named by Alfred Rehder | Lonicera × purpusii | [
"Biology"
] | 196 | [
"Hybrid plants",
"Plants",
"Hybrid organisms"
] |
66,477,454 | https://en.wikipedia.org/wiki/November%202060%20lunar%20eclipse | A penumbral lunar eclipse will occur at the Moon’s ascending node of orbit on Monday, November 8, 2060, with an umbral magnitude of −0.9356. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into the Earth's penumbra. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. Occurring only about 11 hours after perigee (on November 7, 2060, at 17:15 UTC), the Moon's apparent diameter will be larger.
This eclipse will be too small to be visually perceptible.
Visibility
The eclipse will be completely visible over North and South America, west Africa, Europe, and northern Russia.
Eclipse details
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
Eclipse season
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight. The first and last eclipse in this sequence is separated by one synodic month.
Related eclipses
Eclipses in 2060
A penumbral lunar eclipse on April 15.
A total solar eclipse on April 30.
A penumbral lunar eclipse on October 9.
An annular solar eclipse on October 24.
A penumbral lunar eclipse on November 8.
Lunar Saros 156
Preceded by: Lunar eclipse of October 28, 2042
Followed by: Lunar eclipse of November 19, 2078
Triad
Followed by: Lunar eclipse of September 9, 2147
Lunar eclipses of 2056–2060
Metonic series
This eclipse is the fifth and final of five Metonic cycle lunar eclipses on the same date, November 8–9, each separated by 19 years:
References
2060-11
2060-11 | November 2060 lunar eclipse | [
"Astronomy"
] | 472 | [
"Future astronomical events",
"Future lunar eclipses"
] |
66,478,194 | https://en.wikipedia.org/wiki/Cayley%20configuration%20space | In the mathematical theory of structural rigidity, the Cayley configuration space of a linkage over a set of its non-edges , called Cayley parameters, is the set of distances attained by over all its frameworks, under some -norm. In other words, each framework of the linkage prescribes a unique set of distances to the non-edges of , so the set of all frameworks can be described by the set of distances attained by any subset of these non-edges. Note that this description may not be a bijection. The motivation for using distance parameters is to define a continuous quadratic branched covering from the configuration space of a linkage to a simpler, often convex, space. Hence, obtaining a framework from a Cayley configuration space of a linkage over some set of non-edges is often a matter of solving quadratic equations.
Cayley configuration spaces have a close relationship to the flattenability and combinatorial rigidity of graphs.
Definitions
Cayley configuration space
Definition via linkages. Consider a linkage , with graph and -edge-length vector (i.e., -distances raised to the power, for some -norm) and a set of non-edges of . The Cayley configuration space of over in under the for some -norm, denoted by , is the set of -distance vectors attained by the non-edges over all frameworks of in . In the presence of inequality -distance constraints, i.e., an interval , the Cayley configuration space is defined analogously. In other words, is the projection of the Cayley-Menger semialgebraic set, with fixed or , onto the non-edges , called the Cayley parameters.
Definition via projections of the distance cone. Consider the cone of vectors of pairwise -distances between points. Also consider the -stratum of this cone , i.e., the subset of vectors of -distances between points in . For any graph , consider the projection of onto the edges of , i.e., the set of all vectors of -distances for which the linkage has a framework in . Next, for any point in and any set of non-edges of , consider the fiber of in along the coordinates of , i.e., the set of vectors of -distances for which the linkage has a framework in .
The Cayley configuration space is the projection of this fiber onto the set of non-edges , i.e., the set of -distances attained by the non-edges in over all frameworks of in . In the presence of inequality -distance constraints, i.e., an interval , the Cayley configuration space is the projection of a set of fibers onto the set of non-edges .
Definition via branching covers. A Cayley configuration space of a linkage in is the base space of a branching cover whose total space is the configuration space of the linkage in .
Oriented Cayley configuration space
For a 1-dof tree-decomposable graph with base non-edge , each point of a framework of a linkage in under the -norm can be placed iteratively according to an orientation vector , also called a realization type. The entries of are local orientations of triples of points for all construction steps of the framework. A -oriented Cayley configuration space of over , denoted by is the Cayley configuration space of over restricted to frameworks respecting . In other words, for any value of in , corresponding of frameworks of respect and are a subset of the frameworks in .
Minimal complete Cayley vector
For a 1-dof tree-decomposable graph with low Cayley complexity on a base non-edge , a minimal Cayley vector is a list of non-edges of such that the graph is generically globally rigid.
Properties
Single interval property
A pair , consisting of a graph and a non-edge , has the single interval property in under some -norm if, for every linkage , the Cayley configuration space is a single interval.
Inherent convexity
A graph has an inherent convex Cayley configuration space in under some norm if, for every partition of the edges of into and and every linkage , the Cayley configuration space is convex.
Genericity with respect to convexity
Let be a graph and be a nonempty set of non-edges of . Also let be a framework in of any linkage whose constraint graph is and consider its corresponding -edge-length vector in the cone , where . As defined in Sitharam & Willoughby, the framework is generic with respect to the property of convex Cayley configuration spaces if
There is an open neighborhood of in the -stratum (corresponding to a neighborhood around of frameworks in ); and
is convex if and only if, for all , is convex.
Theorem. Every generic framework of a graph in has a convex Cayley configuration space over a set of non-edges if and only if every linkage does.
Theorem. Convexity of Cayley configuration spaces is not a generic property of frameworks.
Proof. Consider the graph in Figure 1. Also consider the framework in whose pairwise -distance vector assigns distance 3 to the unlabeled edges, 4 to , and 1 to and the 2-dimensional framework whose pairwise -distance vector assigns distance 3 to the unlabeled edges, 4 to , and 4 to . The Cayley configuration space is 2 intervals: one interval represents frameworks with vertex on the right side of the line defined by vertices and and the other interval represents frameworks with vertex on the left side of this line. The intervals are disjoint due to the triangle inequalities induced by the distances assigned to the edges and . Furthermore, is a generic framework with respect to convex Cayley configuration spaces over in : there is a neighborhood of frameworks around whose Cayley configuration spaces are 2 intervals.
On the other hand, the Cayley configuration space is a single interval: the triangle-inequalities induced by the quadrilateral containing define a single interval that is contained in the interval defined by the triangle inequalities induced by the distances assigned to the edges and . Furthermore, is a generic framework with respect to convex Cayley configuration spaces over in : there is a neighborhood of frameworks around whose Cayley configuration spaces over in are a single interval. Thus, one generic framework has a convex Cayley configuration space while another does not.
Generic completeness
A generically complete, or just complete, Cayley configuration space is a Cayley configuration of a linkage over a set of non-edges such that each point in this space generically corresponds to finitely many frameworks of and the space has full measure. Equivalently, the graph is generically minimally-rigid.
Results for the Euclidean norm
The following results are for Cayley configuration spaces of linkages over non-edges under the -norm, also called the Euclidean norm.
Single interval theorems
Let be a graph. Consider a 2-sum decomposition of , i.e., recursively decomposing into its 2-sum components. The minimal elements of this decomposition are called the minimal 2-sum components of .
Theorem. For , the pair , consisting of a graph and a non-edge , has the single interval property in if and only if all minimal 2-sum components of that contain are partial 2-trees.
The latter condition is equivalent to requiring that all minimal 2-sum components of that contain are 2-flattenable, as partial 2-trees are exactly the class of 2-flattenable graphs (see results on 2-flattenability). This result does not generalize for dimensions . The forbidden minors for 3-flattenability are the complete graph and the 1-skeleton of the octahedron (see results on 3-flattenability). Figure 2 shows counterexamples for . Denote the graph on the left by and the graph on the right by . Both pairs and have the single interval property in : the vertices of can rotate in 3-dimensions around a plane. Also, both and are themselves minimal 2-sum components containing . However, neither nor is 3-flattenable: contracting in yields and contracting in yields .
Example. Consider the graph in Figure 3 whose non-edges are and . The graph is its own and only minimal 2-sum component containing either non-edge. Additionally, the graph is a 2-tree, so is a partial 2-tree. Hence, by the theorem above both pairs and have the single interval property in .
The following conjecture characterizes pairs with the single interval property in for arbitrary .
Conjecture. The pair , consisting of a graph and a non-edge , has the single interval property in if and only if for any minimal 2-sum component of that contains and is not -flattenable, must be either removed, duplicated, or contracted to obtain a forbidden minor for -flattenability from .
1-dof tree-decomposable linkages in R2
The following results concern oriented Cayley configuration spaces of 1-dof tree-decomposable linkages over some base non-edge in . Refer to tree-decomposable graphs for the definition of generic linkages used below.
Theorem. For a generic 1-dof tree-decomposable linkage with base non-edge the following hold:
An oriented Cayley configuration space is a set of disjoint closed real intervals or empty;
Any endpoint of these closed intervals corresponds to the length of in a framework of an extreme linkage; and
For any vertex or any non-edge of , the maps from to the coordinates of or the length of in the frameworks of are continuous functions on each of these closed intervals.
This theorem yields an algorithm to compute (oriented) Cayley configuration spaces of 1-dof tree-decomposable linkages over a base non-edge by simply constructing oriented frameworks of all extreme linkages. This algorithm can take time exponential in the size of the linkage and in the output Cayley configuration space. For a 1-dof tree-decomposable graph , three complexity measures of its oriented Cayley configuration spaces are:
Cayley size: the maximum number of disjoint closed real intervals in the Cayley configuration space over all linkages ;
Cayley computational complexity: the maximum time complexity to obtain these intervals over all linkages ; and
Cayley algebraic complexity: the maximum algebraic complexity of describing each endpoint of these intervals over all linkages .
Bounds on these complexity measures are given in Sitharam, Wang & Gao. Another algorithm to compute these oriented Cayley configuration spaces achieves linear Cayley complexity in the size of the underlying graph.
Theorem. For a generic 1-dof tree-decomposable linkage , where the graph has low Cayley complexity on a base non-edge , the following hold:
There exist at most two continuous motion paths between any two frameworks of ,
and the time complexity to find such a path, if it exists, is linear in the number of interval endpoints of the oriented Cayley configuration space over that the path contains; and
There is an algorithm that generates the entire set of connected components of the configuration space of frameworks of ,
and the time complexity of generating each such component is linear in the number of interval endpoints of the oriented Cayley configuration space over that the component contains.
An algorithm is given in Sitharam, Wang & Gao to find these motion paths. The idea is to start from one framework located in one interval of the Cayley configuration space, travel along the interval to its endpoint, and jump to another interval, repeating these last two steps until the target framework is reached. This algorithm utilizes the following facts: (i) there is a continuous motion path between any two frameworks in the same interval, (ii) extreme linkages only exist at the endpoints of an interval, and (iii) during the motion, the low Cayley complexity linkage only changes its realization type when jumping to a new interval and exactly one local orientation changes sign during this jump.
Example. Figure 4 shows an oriented framework of a 1-dof tree-decomposable linkage with base non-edge , located in an interval of the Cayley configuration space, and two other frameworks whose orientations are about to change. The vertices corresponding to construction steps are labelled in order of construction. More specifically, the first framework has the realization type . There is a continuous motion path to the second framework, which has the realization type . Hence, this framework corresponds to an interval endpoint and jumping to a new interval results in the realization type . Likewise, the third framework is corresponds to an interval endpoint with the realization type and jumping to a new interval results in the realization type .
Theorem. (1) For a generic 1-path, 1-dof tree-decomposable linkage with low Cayley complexity, there exists a bijective correspondence between the set of frameworks of and points on a 2-dimensional curve, whose points are the minimum complete Cayley distance vectors. (2) For a generic 1-dof tree-decomposable linkage with low Cayley complexity, there exists a bijective correspondence between the set of frameworks of and points on an -dimensional curve, whose points are the minimum complete Cayley distance vectors, where is the number of last level vertices of the graph .
Results for general p-norms
These results are extended to general -norms.
Theorem. For general -norms, a graph has an inherent convex Cayley configuration space in if and only if is -flattenable.
The "only if" direction was proved in Sitharam & Gao using the fact that the distance cone is convex. As a direct consequence, -flattenable graphs and graphs with inherent convex Cayley configuration spaces in have the same forbidden minor characterization. See Graph flattenability for results on these characterizations, as well as a more detailed discussion on the connection between Cayley configuration spaces and flattenability.
Example. Consider the graph in Figure 3 with both non-edges added as edges. The resulting graph is a 2-tree, which is 2-flattenable under the and norms, see Graph flattenability. Hence, the theorem above indicates that the graph has an inherent convex Cayley configuration space in under the and norms. In particular, the Cayley configuration space over one or both of the non-edges and is convex.
Applications
The EASAL algorithm makes use of the techniques developed in Sitharam & Gao for dealing with convex Cayley configuration spaces to describe the dimensional, topological, and geometric structure of Euclidean configuration spaces in . More precisely, for two sets of points and in with interval distance constraints between pairs of points coming from different sets, EASAL outputs all the frameworks of this linkage such that no pair of constrained points is too close together and at least one pair of constrained points is sufficiently close together. This algorithm has applications in molecular self-assembly.
References
Mathematics of rigidity | Cayley configuration space | [
"Physics"
] | 3,146 | [
"Mathematics of rigidity",
"Mechanics"
] |
66,478,319 | https://en.wikipedia.org/wiki/IRAS%2000500%2B6713 | IRAS 00500+6713 is the catalogued infrared source for an unusual nebula in Cassiopeia, while the central star has a designation WD J005311, with the whole system designated as Pa 30. The central star and its surrounding shell were created by the supernova seen in the year 1181 (SN 1181) as reported by Chinese and Japanese observers. Both the nebula and central star have unique and extreme properties, pointing to their creation by a rare type Iax supernova, where two ultra-dense white dwarfs in-spiral to a collision and explosion.
The Pa 30 system was discovered in 2013 by amateur astronomer Dana Patchick. It was independently discovered by Dr. Vasili Gvaramadze and colleagues who first realized that the central star has extreme properties and proposed that it was created from a merger of two white dwarfs. The star exhibits record-breaking wind speeds of 16,000 km/s and temperatures near 200,000 K. The central star, might be a rapidly-rotating super-Chandrasekhar white dwarf with a mass .
The central star is surrounded by a nebula packed with hot gas and warm dust. X-ray observations with the XMM-Newton telescope established that the star and its circumstellar nebula are strong X-ray sources. Analysis of X-ray spectra allowed for the first time to determine the chemical composition of the nebula. It was proposed that the nebula is a remnant of a rare type of supernova (SN Iax), and that the SN happened some 1000 years ago.
It has been linked to the historic supernova SN 1181. The star is possibly highly unstable, too massive to remain as a white dwarf, and it is predicted to collapse into a neutron star within ten thousand years.
Both the central star and the nebula contain large amounts of neon, magnesium, silicon, and sulfur (but no hydrogen, helium, or nitrogen), with such requiring an origin in a recent supernova. The surrounding shell has a unique structure with long radial filaments that have expansion velocities of around 1100 km/s. Apparently, the filaments are the tattered remains of the original `slow' supernova ejecta, fragmented and streamed into long wakes by the on-going very fast stellar wind emanating from the central white dwarf.
References
White dwarfs
Cassiopeia (constellation)
IRAS catalogue objects
Supernova remnants | IRAS 00500+6713 | [
"Astronomy"
] | 498 | [
"Cassiopeia (constellation)",
"Constellations"
] |
76,788,023 | https://en.wikipedia.org/wiki/Azadiradione | Azadiradione is a naturally occurring compound found in several plants, most notably the neem tree (Azadirachta indica). It is a tetracyclic triterpenoid.
Sources
Azadiradione is the principal active ingredient in neem oil, which is extracted from the seeds of the neem tree. Smaller quantities of azadiradione can also be found in other plants like Cedrela odorata (Spanish cedar), Chisocheton siamensis, Xylocarpus granatum (cannonball mangrove) and Azalea indica (common azalea).
Applications
Azadiradione acts as an antioxidant and has been used in traditional medicine in Asia, Africa and the Middle East for ages.
Research suggests azadiradione may have properties that fight microbes (bacteria, fungi, viruses), reduce inflammation, protect cells from damage, and even have anti-cancer effects.
Azadiradione may also act as a natural pesticide, potentially controlling some insects and pests.
References
Terpenes and terpenoids
Secondary metabolites
Triterpenoids
Acetate esters
3-Furyl compounds | Azadiradione | [
"Chemistry"
] | 248 | [
"Biomolecules by chemical classification",
"Natural products",
"Chemical ecology",
"Secondary metabolites",
"Organic compounds",
"Terpenes and terpenoids",
"Metabolism"
] |
76,788,084 | https://en.wikipedia.org/wiki/Tetrapropylammonium | Tetrapropylammonium (TPA) is a quaternary ammonium cation with the formula , also denoted (where Pr = propyl group). It is a precursor to several significant industrial and laboratory catalysts.
Properties
TPA is chemically similar to other quaternary ammonium cations with saturated alkyl groups. As such, it is highly electrochemically stable, degrading only in the presence of particularly strong bases and nucleophiles.
It is isoelectronic with tetrapropyltin and the tetrapropylboranuide anion.
Synthesis
Like other quaternary ammonium cations, TPA is prepared by the alkylation of the corresponding ammonia analogue, tripropylamine. Treatment of the amine with a primary propyl halide such as n-bromopropane yields the corresponding TPA halide salt in a Menshutkin reaction:
The halide salts are then converted to the more industrially valuable hydroxide by reaction with aqueous silver oxide, electrolysis, ion-exchange resin, or electrodialysis.
Applications
The tetrapropylammonium cation is used as a structure-directing agent in the production of synthetic zeolites, in particular ZSM-5 and titanium-bearing TS-1 catalysts. After synthesis, TPA is removed by thermolysis.
The TPA salt tetrapropylammonium perruthenate (TPAP) is an effective and highly selective oxidiser, with numerous applications in organic synthesis. Combined with a cooxidant, it serves as a catalyst for the oxidation of primary and secondary alcohols to aldehydes and ketones.
References
Quaternary ammonium compounds
Propyl compounds
Cations | Tetrapropylammonium | [
"Physics",
"Chemistry"
] | 368 | [
"Cations",
"Ions",
"Matter"
] |
76,788,356 | https://en.wikipedia.org/wiki/Mesokaryote | A mesokaryote or mesokaryotic organism is a single-celled eukaryote that shows intermediate resemblance to both prokaryotes and 'higher' eukaryotes. The term originates from a 1965 hypothesis by John David Dodge, who proposed that certain eukaryotes (mainly dinoflagellates) with closed mitosis and other traits considered 'primitive' were an intermediate step between prokaryotes and the remaining eukaryotes. This idea originated in the late 20th century, and was later disproven by more detailed ultrastructural studies in the following decades.
History
The first investigations of the dinoflagellate nucleus, during the 1950s-1960s, revealed a fine nucleus and chromosome structure that was completely different from other nucleated organisms or eukaryotes, lacking histones and with a permanently condensed chromatin. Based on these findings, the phycologist John David Dodge proposed in 1965 the concept of Mesocaryota (or mesokaryotes) under the hypothesis that these features were an intermediate nuclear organization between prokaryotes and eukaryotes. This hypothesis led to the theory that dinoflagellates were the first to evolve from the split with prokaryotes, followed by the remaining eukaryotes. The traits considered by Dodge to define Mesocaryota were: lack of detectable histones; absence of a mitotic spindle; continuous DNA synthesis; chromatin fibrils arranged in arched swirls as in bacterial nucleoids; and chromosomes permanently condensed persistently adhered to the nuclear envelope, which remains intact throughout mitosis (i.e., it is a closed mitosis).
The mesokaryote hypothesis was disproven in the following decades through more detailed observations of the criteria listed above. For example, detailed studies on the parasitic Syndinium demonstrated the presence of an unconventional type of basic histone-like proteins and of an extranuclear mitotic spindle in dinoflagellates, similarly to 'higher' eukaryotes. Dinoflagellates remained considered a group of ancient but true eukaryotes. With the improvement of molecular phylogenetics, dinoflagellates, like other groups that exhibited closed mitosis, were instead revealed to be derived, branching within the Alveolata, whose members have conventional nuclei. Thus, these traits were reinterpreted as highly derived. Due to its short lifespan, the mesokaryote hypothesis has had little impact.
References
Eukaryotes
Obsolete biology theories | Mesokaryote | [
"Biology"
] | 537 | [
"Tree of life (biology)",
"Eukaryotes",
"Biology theories",
"Obsolete biology theories"
] |
76,788,845 | https://en.wikipedia.org/wiki/Obligate%20mutualism | Obligate mutualism is a special case of mutualism where an ecological interaction between species mutually benefits each other, and one or all species are unable to survive without the other. In some obligate relationships, only one species is dependent on the relationship. For example, a parasite may require a host in order to reproduce and survive, while the host does not depend at all on the parasite. Fig and fig wasps are an example of a co-obligate relationship, where both species are totally dependent on the relationship. The fig plant is entirely dependent on the fig wasp for pollination, and the fig wasp requires the fig plant for reproductive purposes. Many insect-fungi relationships are also co-obligate: the insect disperses, and in some cases protects, the fungi while the fungi provide nutrients for the insects. This interaction allows insects and fungi to, as a group, inhabit previously inhospitable or unreachable environments. Though obligate relationships need not be limited to two species, they are often discussed as such, with the relationship being made up of a host and a symbiont, though the terms are often attributed arbitrarily.
Evolution of obligate mutualism
Obligate mutualistic relationships, where species are entirely dependent on each other for survival, can evolve through different pathways. In some cases, a free-living symbiont may be engulfed by a host organism and subsequently passed down through vertical transmission, resulting in an obligate dependency. However, it is more common for facultative mutualisms, where the mutualist can exist independently or in association with a host, to act as an intermediary step toward the evolution of obligate or co-obligate mutualism. In this second case, the evolution of obligate mutualism can be divided into three steps: formation, maintenance, and transformation.
Formation
The formation of the facultative mutualism requires that the species involved all benefit from their mutual cooperation. This mutualism, though it is to the benefit of said species, is best understood as co-exploitation. Facultative mutualism occurs when species' interests align, so that each may reciprocally exploit the other to the benefit of both.
Maintenance
In order for facultative relationships to turn into obligate relationships, the facultative mutualism must be maintained and continued across generations. There are two methods for the relationship to be carried through generations: vertical and horizontal transmission. Vertical transmission involves the passage of symbionts from parent to offspring hosts. Horizontal transmission involves the passage of symbionts between unrelated hosts. It is proposed that vertical transmission makes for a more stable relationship, because in vertical transmission a host is paired with the same symbiont in every generation, thus the host and symbiont have more chance for co-adaption. In vertical transmission, the hosts and symbionts also share reproductive fate and therefore both suffer from cheating.
A cheater is a mutualist who gains more than they get. An extreme example would be an organism who gains from a relationship without giving anything, such as an insect that feeds on nectar without contributing to pollination. Cheaters are thought to destabilize mutualistic relationships, both when they arrive as a third exploitative party and when they result as mutants within pre-existing mutualistic relationships. Horizontal transmission, where there can be multiple symbionts, can result in competition between symbionts and exploitation of the host.
There are many obligate relationships involving horizontal transmission. And it has also been found that mutualist/exploiter co-existence is not uncommon. Cheaters often exist alongside mutualistic relationships, and in obligate mutualism the presence of third party explorers early in the formation of the relationship may protect the host-symbiont relationship from further exploitation later on.
Transformation
Once a mutualistic group has reached a point of stability, where both species are benefiting and there is not a destabilizing problem with cheaters, the third stage, transformation, can occur. In this stage, the mutualists lose the ability to survive independently of one another and thus form a new superorganism. In this case, each symbiont has become so specialized within the mutualistic group that they are now fully dependent on the relationship.
Physiological and behavioral changes can evolve as consequences of obligate dependency. In insect-fungi mutualistic groups, for example, fungal spore-carrying organs in insects and the production of increasingly nutrient rich, asexually reproductive spores in fungi appear as part of the co-obligate relationship. In the fig and wasps co-obligate relationship, female wasps have developed morphological traits, such as elongated heads and easily detachable antennae and wings, that allow them to enter the fig ostile and lay eggs and collect pollen, and likewise, as the fig matures it produces nourishment for the wasp larvae.
Evolutionary consequences
Obligate dependency links the evolutionary fate of the organisms involved, this coupling has the potential to result in both negative and positive consequences. This coupling can enhance the ability of the organism to evolve because natural selection can influence two genomes at once, meaning there are more opportunities for a mutation to positively impact both species. This coupling also has the potential to negatively affect species evolution by limiting the ability of one species to react to environmental selective pressures, tying the organism with the higher fitness to an organism with now lower fitness, this is called the weakest link hypothesis.
Studying obligate mutualism
Understanding how obligate dependency affects the evolution of involved species as well as being able to properly identify and understand obligate relationships is important in predicting and perhaps guardian against the impacts of climate change on ecological communities. It is not easy to study or identify obligate species and the number of species involved in obligate relationships, as hosts and symbionts lose and gain traits in their relationship, making it hard to determine their taxonomic relationships with other species. Studying obligate relationships is also difficult, as they do not respond well to experimental interference.
References
Mutualism (biology)
Biological interactions
Ethology | Obligate mutualism | [
"Biology"
] | 1,261 | [
"Behavior",
"Symbiosis",
"Biological interactions",
"Behavioural sciences",
"Mutualism (biology)",
"nan",
"Ethology"
] |
76,793,082 | https://en.wikipedia.org/wiki/Amy%20Betz | Amy Rachel Betz is an American materials scientist whose research investigates the effects of water-attracting and water-repelling surfaces on heat transfer and on icing of aircraft surfaces. She is an associate professor of mechanical and nuclear engineering at Kansas State University, where she also serves as assistant dean for retention, diversity and inclusion.
Education and career
Betz has a 2006 bachelor's degree in mechanical engineering from George Washington University. She went to Columbia University for graduate study in mechanical engineering, earning a master's degree in 2008 and completing her Ph.D. in 2011. Her doctoral dissertation, Multiphase Microfluidics for Convective Heat Transfer and Manufacturing, was supervised by Daniel Attinger.
Before she completed her studies, Betz worked in hotel management. She joined the Kansas State University faculty in 2011, She became assistant dean for retention, diversity and inclusion in the Kansas State University College of Engineering in 2019.
Recognition
Betz's efforts to encourage women in engineering were recognized by the K-State Office for the Advancement of Women in Science and Engineering, which gave her their KAWSE Award in 2016, and again in 2023.
In 2017, the American Society of Mechanical Engineers (ASME) International Conference on Nanochannel, Microchannels, and Minichannels gave her their Outstanding Leadership Award. She was elected as an ASME Fellow in 2022.
References
External links
Home page (not regularly updated since 2016)
Q&A with Betz, Engineergirl
Year of birth missing (living people)
Living people
American materials scientists
American women engineers
Women materials scientists and engineers
George Washington University alumni
Columbia University alumni
Kansas State University faculty
Fellows of the American Society of Mechanical Engineers | Amy Betz | [
"Materials_science",
"Technology"
] | 341 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
76,793,346 | https://en.wikipedia.org/wiki/Attribute%20blocks | Attribute blocks, also called logic blocks, are mathematical manipulatives used to teach logic.
Each block in a set has a unique combination of four attributes, namely size, color, shape, and thickness.
References
Mathematical manipulatives | Attribute blocks | [
"Mathematics"
] | 50 | [
"Recreational mathematics",
"Mathematical manipulatives"
] |
76,794,264 | https://en.wikipedia.org/wiki/NGC%203750 | NGC 3750 is a lenticular galaxy with a bar located in the constellation of Leo. It is located 450 million light-years from the Solar System and was discovered by Ralph Copeland on February 9, 1874.
NGC 3750 has a surface brightness of magnitude 23.7 and is classified a LINER galaxy by SIMBAD, meaning it has a nucleus, presenting an emission spectrum characterized by broad lines of weakly ionized atoms.
Copeland Septet
NGC 3750 is a member of the Copeland Septet which is made up of 7 seven galaxies discovered by Copeland. The other members are NGC 3745, NGC 3746, NGC 3748, NGC 3751, NGC 3753 and NGC 3754.
Halton Arp noticed the galaxies in the group, whom he published in his article in 1966. This group is designated as Arp 320 along with another galaxy, PGC 36010.
This group was also observed by Paul Hickson whom he included in his article in 1982. The group is known as Hickson 57, in which NGC 3750 is designated is HCG 57C.
References
3750
036011
Leo (constellation)
Lenticular galaxies
Discoveries by Ralph Copeland
Astronomical objects discovered in 1874
036011
320
Hickson Compact Groups
2MASS objects
SDSS objects
+04-28-008
Copeland Septet | NGC 3750 | [
"Astronomy"
] | 265 | [
"Leo (constellation)",
"Constellations"
] |
76,794,436 | https://en.wikipedia.org/wiki/NGC%203748 | NGC 3748 is a lenticular galaxy with a bar located in the Leo constellation. It is located 440 million light-years away from the Solar System and was discovered by Ralph Copeland on April 5, 1874, but also observed by Hermann Kobold, Lawrence Parsons and John Louis Emil Dreyer.
Like NGC 3746, NGC 3748 also has a recessed core (RET). It is described as, "moderately bright, fairly small, slightly elongated NW-SE, 0.4'x0.3' with a small bright core".
Copeland Septet
NGC 3748 is a member of the Copeland Septet which is made up of 7 galaxies which were discovered by Copeland in 1874. The other members are NGC 3745, NGC 3746, NGC 3750, NGC 3751, NGC 3753 and NGC 3754.
Halton Arp noticed the galaxies in this group in an article that was published in 1966. This group is known as Arp 320 along with another galaxy, PGC 36010.
This group was observed by Paul Hickson whom he included in his article in 1982. The group is known as Hickson 57, in which NGC 3748 is designated as HCG 57E.
References
3748
36007
LEDA objects
2MASS objects
Discoveries by Ralph Copeland
Astronomical objects discovered in 1874
Leo (constellation)
Lenticular galaxies
320
Hickson Compact Groups
Copeland Septet | NGC 3748 | [
"Astronomy"
] | 284 | [
"Leo (constellation)",
"Constellations"
] |
76,794,511 | https://en.wikipedia.org/wiki/10-Hydroxyketotifen | 10-Hydroxyketotifen (WR621365) is a biologically inactive metabolite of ketotifen. Despite the mainstream scientific consensus that 10-hydroxyketotifen is a biologically inactive compound, its pharmacological properties are not very well studied outside the context of ketotifen, therefore, 10-hydroxyketotifen may still possess biological activity similarly to norketotifen, another metabolite of ketotifen.
Metabolic role
Ketotifen is an antihistamine medication which metabolizes to several compounds, including 10-hydroxyketotifen. Ketotifen, like other antihistamines, is mainly metabolized by the cytochrome P450 (CYP) enzymes, especially CYP3A4 in the liver. The CYP enzymes are responsible for the oxidation and demethylation of ketotifen, producing the major metabolites norketotifen and 10-hydroxyketotifen. Norketotifen is pharmacologically active and has a similar potency as ketotifen, while 10-hydroxyketotifen is inactive. The metabolites are then conjugated with glucuronic acid or sulfate and excreted in the urine and feces.
The definition and measurement of biological activity of drugs can be complex: biological activity is often defined in terms of the ability of a molecule to effect a change in a biological process, which can be quantified and measured in various ways; as such, even if 10-hydroxyketotifen is currently deemed inactive, it is possible that under certain conditions or within specific biological assays, some level of activity might be observed.
References
Benzocycloheptathiophenes
Tricyclic compounds
Metabolic intermediates
Piperidines
Secondary alcohols | 10-Hydroxyketotifen | [
"Chemistry"
] | 395 | [
"Metabolic intermediates",
"Metabolism",
"Biomolecules"
] |
76,794,581 | https://en.wikipedia.org/wiki/NGC%203754 | NGC 3754 is a small barred spiral galaxy located in Leo. It is located 447 million light-years away from the Solar System and was discovered on April 5, 1874, by Ralph Copeland.
The luminosity class of NGC 3754 is II and it is listed as a LINER galaxy by SIMBAD, meaning, a nucleus presenting an emission spectrum characterized by broad lines of weak ionized atoms.
Copeland Septet
NGC 3754 is a member of the Copeland Septet which is made up of 7 galaxies discovered by Copeland in 1874. The other members of the group, are NGC 3745, NGC 3746, NGC 3748, NGC 3750, NGC 3751 and NGC 3753.
Halton Arp noticed the 7 galaxies in an article published in 1966. This group is designated as Arp 320 in which PGC 36010 is part of them.
The 7 galaxies were also observed by Paul Hickson, in which he included them inside his article in 1982. This group is known as Hickson 57, in which NGC 3754 is designated as HCG 57D.
References
3746
036018
Leo (constellation)
Barred spiral galaxies
Discoveries by Ralph Copeland
Astronomical objects discovered in 1874
036018
SDSS objects
2MASS objects
320
Hickson Compact Groups
Copeland Septet | NGC 3754 | [
"Astronomy"
] | 260 | [
"Leo (constellation)",
"Constellations"
] |
76,794,975 | https://en.wikipedia.org/wiki/IC%201189 | IC 1189 is a S0-a lenticular galaxy with a ring structure located in Hercules. It is located 557 million light-years away from the Solar System and has an approximate diameter of 145,000 light-years. IC 1189 was discovered on June 7, 1888, by Lewis Swift. It is a member of the Hercules Cluster.
IC 1189 has an active galactic nucleus and is classified as a starburst galaxy meaning to say, it is a powerhouse star factory making stars at a rate hundred of times greater compared to the Milky Way. Additionally, it falls into the Markarian galaxies category as Mrk 300, in which its core shines in ultraviolet rays.
References
1189
Lenticular galaxies
Starburst galaxies
Hercules (constellation)
057135
2MASS objects
SDSS objects
Discoveries by Lewis Swift
Astronomical objects discovered in 1888
Markarian galaxies
+03-41-119
IRAS catalogue objects
Hercules Cluster | IC 1189 | [
"Astronomy"
] | 189 | [
"Hercules (constellation)",
"Constellations"
] |
76,795,092 | https://en.wikipedia.org/wiki/IC%201192 | IC 1192 is an edge-on barred spiral galaxy located in Hercules. It is located 543 million light-years from the Solar System and has a diameter of approximately 90,000 light-years. IC 1192 was discovered by Stephane Javelle on August 13, 1892. It is a member of the Hercules Cluster.
The luminosity class of IC 1192 is II and it has an active galaxy nucleus. It is specifically described as a LINER galaxy according to SIMBAD, meaning its nucleus presents an emission spectrum characterized by broad lines of weak ionized atoms.
References
1192
057157
057157
SDSS objects
Astronomical objects discovered in 1892
Hercules (constellation)
Hercules Cluster
Barred spiral galaxies | IC 1192 | [
"Astronomy"
] | 145 | [
"Hercules (constellation)",
"Constellations"
] |
76,800,402 | https://en.wikipedia.org/wiki/Planon | Planon is a developer and supplier of software for building management, including real estate and facilities management, such as IWMS, CMMS and CAFM systems.
Planon is based in Nijmegen, the Netherlands, and has more than 20 offices in Europe, North America and Asia. Planon’s software is used worldwide.
History
Planon was founded in 1982 by Pierre Guelen and rapidly grew to become the computer-aided facility management (CAFM) software market leader in the Netherlands. In the late 1990s, Planon began to expand abroad. The software has been repeatedly rated as global market leader by analyst reports such as Verdantix , IDC MarketScape, Gartner and Frost & Sullivan.
In 2020, it was announced that the French multinational company Schneider Electric would take a minority stake in Planon. In 2024, Schneider Electric signed an agreement to increase its stake in Planon to a majority interest of 80%.
In 2023, Planon and SAP announced that they have formed a strategic partnership with Planon.
In May 2024, Peter Ankerstjerne (former Chief Strategy Officer) was named as the successor to Pierre Guelen as CEO, set to take over in June 2024, following the founder's 42-year tenure.
References | Planon | [
"Technology"
] | 266 | [
"Computer industry",
"IT service management"
] |
76,803,556 | https://en.wikipedia.org/wiki/NGC%203745 | NGC 3745 is a lenticular galaxy with a bar structure located in the constellation of Leo. NGC 3745 is located 471 million light-years away from the Solar System and was discovered by Ralph Copeland on April 5, 1874, but also observed by Hermann Kobold, Lawrence Parsons and John Louis Emil Dreyer.
Copeland Septet
NGC 3745 is a member of the Copeland Septet. The other members of the group are NGC 3746, NGC 3748, NGC 3750, NGC 3751, NGC 3753 and NGC 3754.
Halton Arp noticed the group when he published the article in 1966. The group is designated as Arp 320 in which another galaxy PGC 36010, is part of it.
This group was also observed by Paul Hickson, in which he included them inside his article in 1982. This group is known as Hickson 57, in which NGC 3745 is designated as HCG 57G.
References
3745
36001
Discoveries by Ralph Copeland
Astronomical objects discovered in 1874
+04-28-004
2MASS objects
SDSS objects
Leo (constellation)
320
Hickson Compact Groups
Lenticular galaxies
Copeland Septet | NGC 3745 | [
"Astronomy"
] | 235 | [
"Leo (constellation)",
"Constellations"
] |
76,803,836 | https://en.wikipedia.org/wiki/NGC%203751 | NGC 3751 is a type E-S0 lenticular galaxy located in the Leo constellation. It is located 450 million light-years away from the Solar System and was discovered by Ralph Copeland on April 5, 1874.
To date, a non-redshift measurement gives a distance of approximately 138,000 Mpc (450 million light-years) for NGC 3751. This value is within the Hubble Distance values.
Copeland Septet
NGC 3751 is a member of the Copeland Septet. The other members are NGC 3745, NGC 3746, NGC 3748, NGC 3750, NGC 3753 and NGC 3754.
Halton Arp noticed the 7 galaxies in which he published inside his article in 1966. This group is known as Arp 320 in which another galaxy, PGC 36010 is part of it.
This group was also observed by Paul Hickson, in which he included them inside his article which was published in 1982. It is noted that this group is designated as Hickson 57. NGC 3751 is known as HCG 57F.
References
3751
036017
06601
Leo (constellation)
Discoveries by Ralph Copeland
Astronomical objects discovered in 1874
Lenticular galaxies
2MASS objects
SDSS objects
320
Hickson Compact Groups
Copeland Septet | NGC 3751 | [
"Astronomy"
] | 259 | [
"Leo (constellation)",
"Constellations"
] |
76,804,246 | https://en.wikipedia.org/wiki/IC%202759 | IC 2759 is a small type E elliptical galaxy located in the constellation of Leo. It is located 350 million light-years away from the Solar System and was discovered on April 24, 1897, by Guillaume Bigourdan. Sometimes IC 2759 is confused with the spiral galaxy, PGC 34882 which is located south of the galaxy.
Supernova
One supernova has been discovered in IC 2759 so far: SN 2020lyo.
SN 2020lyo
SN 2020lyo was discovered in IC 2759 by astronomer, Dr. David Bersier on 8 June 2020 from All Sky Automated Survey for SuperNovae (ASAS-SN). via a Liverpool Telescope. It was 0".5 west and 0".0 south of the nucleus and located at redshift of 0.027. The supernova was Type Ia.
Hickson 51
IC 2759 is a member of Hickson 51. It was one of the galaxies observed by Paul Hickson, when he published his article in 1982. The other galaxies in Hickson 51, are NGC 3651, PGC 34882, NGC 3653, PGC 34907, PGC 34899 or NGC 3651 NED02 and PGC 34901. IC 2759 in this case, is listed as HCG 51E.
References
2759
Elliptical galaxies
Hickson Compact Groups
Discoveries by Guillaume Bigourdan
Astronomical objects discovered in 1897
034881
034881
2MASS objects
Leo (constellation)
SDSS objects | IC 2759 | [
"Astronomy"
] | 317 | [
"Leo (constellation)",
"Constellations"
] |
76,804,399 | https://en.wikipedia.org/wiki/Astronomical%20Observatory%20University%20of%20Warsaw | The Astronomical Observatory University of Warsaw (Polish: Obserwatorium Astronomiczne Uniwersytetu Warszawskiego) is an institute that conducts research and teaching in astronomy. It is a part of the Faculty of Physics University of Warsaw. The Observatory provides astronomy classes for BSc, MSc, and PhD students. Student telescope activities take place at the observing station in Ostrowik. The scientific research is conducted in a wide range of topics including two main observing projects that are long-term optical sky surveys: OGLE and ASAS. Both these surveys take sky images using dedicated telescopes located at the Las Campanas Observatory, Chile. Scientific staff takes part in large astrophysical collaborations, both ground-based (H.E.S.S., CTA, and LIGO/VIRGO) and satellite (Planck and Gaia).
History
The Observatory building was opened in 1825 and the first director was Franciszek Armiński. The building is situated inside Botanical Garden University of Warsaw and next to Łazienki Park. Early on, the main equipment of the Observatory were meridian circles that were used for astrometric observations, geodetic measurements, and time keeping. At the onset of the World War I, part of the equipment was moved to Russia.
In 1937, an observing station run by the Observatory was opened at the Pip Ivan peak (currently in Ukraine) as a part of the White Elephant building. The White Elephant was built by the Airborne and Antigas Defence League. The main instrument at this observing station was 33 cm astrograph build by the Grubb Parsons company. The building was abandoned just after the Soviet aggression on Poland in September 1939. There was only a single research paper published based on observations from Pip Ivan and the station was not used for astronomical research later on.
After the German invasion of Poland, the University of Warsaw was closed but the Observatory was re-opened by the occupant. Very limited research was allowed and the main activity was time keeping. During the Warsaw Uprising the Observatory staff was forced to leave Warsaw and the building was burned by German soldiers. In February 1945, the Observatory was re-established in Kraków. Over next few years, the building in Warsaw was rebuilt and astronomers moved back. At the same time an observing station was established at Ostrowik village near Warsaw. In 1973 the 60 cm telescope was opened in Ostrowik. The research interests of the Observatory after the World War II changed to astrophysics. The first post-war professors were Włodzimierz Zonn and Stefan Piotrowski (starting in 1950s). Their most well known junior colleague was Bohdan Paczyński.
The Observatory hosted a PDP-11/45 computer from 1975 till 1978. The computer was owned by the Polish Academy of Sciences and it was moved to a newly established Nicolaus Copernicus Astronomical Center of the PAS.
The observing capabilities of the Observatory astronomers improved significantly with an advancement of the CCD cameras in astronomy. The first CCD camera in Poland was built for Ostrowik 60 cm telescope by Andrzej Udalski in 1991. The next year, Warsaw astronomers led by Andrzej Udalski and supported by Bohdan Paczyński (at the Princeton University then) started the OGLE project. The OGLE observations were first taken with the Swope telescope at the Las Camapanas Observatory (Chile). In 1996, a 1.3 m telescope dedicated to the OGLE project was opened. At the same time, another Warsaw astronomer, Grzegorz Pojmański, started ASAS survey, which was an implementation of an idea proposed by Paczyński.
Notable employees and students
Adam Prażmowski – first astronomer who observed polarization of solar corona during a total eclipse, which proved that the corona is associated with Sun, not Moon.
Jan Gadomski – employee, active observer, a lunar crater was named after him.
Elena Kazimirtchak-Polonskaïa – the only PhD recipient during the interwar period, studied comets.
Bohdan Paczyński – astrophysicist known for his works on microlensing, stellar evolution, and gamma ray bursts.
Krzysztof Stanek – alumnus known for his research on massive stars and supernovae explosions; one of the leaders of ASAS-SN survey.
Andrzej Udalski – head of the OGLE survey.
Anna Żytkow – alumnus known for suggesting, jointly with Kip Thorne, that there could exist a giant star with a neutron star in its core, called Thorne–Żytkow object.
Gallery
References
Astronomical observatories in Poland
Astronomy institutes and departments
University of Warsaw
Ujazdów, Warsaw
University and college astronomical observatories | Astronomical Observatory University of Warsaw | [
"Astronomy"
] | 979 | [
"Astronomy organizations",
"Astronomy institutes and departments"
] |
76,804,936 | https://en.wikipedia.org/wiki/Toka%20Diagana | Toka Diagana (also published as Tocka Diagana) is a Mauritanian-American mathematician, a professor of mathematics and chair of mathematics at the University of Alabama in Huntsville, and the editor-in-chief of the journal Nonautonomous Dynamical Systems. The topics of his research include functional analysis, stochastic processes, differential equations, dynamical systems, and operator theory.
Education and career
Diagana is originally from Kaédi, in southern Mauritania, a country in Northwest Africa. After attending a top high school in Kaédi, he went north to Tunisia for undergraduate studies at the of Tunis El Manar University. There, his interests in mathematical analysis and topology were sparked by Abdenabi Achour and Said Zarati. At the suggestion of Achour, he traveled to France for doctoral study in mathematics, at Claude Bernard University Lyon 1. He earned a diploma of advanced studies (master's degree) there in 1995, and completed his Ph.D. in 1999, under the direction of Jean-Bernard Baillon, also working in Lyon with Étienne Ghys.
After a brief stint as a secondary school teacher in Thoissey, France, Diagana came to Howard University in the US as a lecturer in 2000, and obtained an assistant professorship there in 2002. He was quickly promoted to associate professor in 2004, and then to full professor in 2007. He moved to his present position as professor and chair at the University of Alabama in Huntsville in 2018.
Contributions
Diagana founded the African Diaspora Journal of Mathematics, and is the editor-in-chief of the journal Nonautonomous Dynamical Systems.
His 13 authored and edited books include both mathematical monographs and multiple compilations of mathematics from researchers of the African diaspora.
Despite many academic publications, in a profile on Mathematically Gifted & Black, he describes his greatest accomplishment as his mentorship of eight African Americans to doctorates in mathematics, including two women, countering the historic underrepresentation of people from these groups in mathematics.
Recognition
Diagana is a 2006 recipient of the Prix Chinguitt, a Mauritanian national prize given annually for excellence in science research. He is a Fellow of the African Academy of Sciences, elected in 2009.
References
External links
Home page
Year of birth missing (living people)
Living people
Mauritian scientists
American mathematicians
African-American mathematicians
Mathematical analysts
Tunis El Manar University alumni
University of Lyon alumni
Howard University faculty
University of Alabama in Huntsville faculty | Toka Diagana | [
"Mathematics"
] | 516 | [
"Mathematical analysis",
"Mathematical analysts"
] |
76,805,178 | https://en.wikipedia.org/wiki/Filter%20and%20refine | Filter and Refine Principle (FRP) is a general computational strategy in computer science.
FRP is used broadly across various disciplines, particularly in information retrieval, database management, and pattern recognition, which efficiently processes large sets of objects through a two-stage approach: filtering and refinement.
The filtering stage quickly eliminates less promising or irrelevant objects from a large set using efficient, less resource-intensive algorithms. This stage is designed to reduce the volume of data that needs to be processed in the more resource-demanding refinement stage.
Following filtering, the refinement stage applies more complex and computationally expensive techniques to the remaining objects to achieve higher accuracy via finer-grained processing. This stage is essential for obtaining the desired quality and precision in the results.
FRP is a general method for completing a computationally intensive task as quickly as possible (Filter and Refine Strategy), which is important in scenarios where managing the inherent trade-offs between speed and accuracy is crucial. Its implementations span various fields and applications, from database indexing/query processing, and information retrieval to machine learning and big data analytics. Its implementation helps in optimizing systems to better manage the inherent trade-offs between speed and accuracy.
Overview
FRP follows a two-step processing strategy:
Filter: an efficient filter function is applied to each object in the dataset . The filtered subset is defined as for value-based tasks, where is a threshold value, or for type-based tasks, where is the target type(s).
Refine: a more complex refinement function is applied to each object in , resulting in the set , or likewise, , as the final output.
This strategy balances the trade-offs between processing speed and accuracy, which is crucial in situations where resources such as time, memory, or computation are limited.
Applications in Specific Fields
Reinforcement Learning
In the domain of artificial intelligence, Reinforcement Learning (RL) demonstrates the Filter and Refine Principle (FRP) through the processes of policy and value function estimation. In RL, agents learn to make decisions by exploring the environment and receiving feedback in the form of rewards. For example, in AlphaZero, the filtering stage in RL involves narrowing down the set of possible actions at each state by using a policy network, which predicts potentially rewarding actions based on previous experiences. This approach reduces the search space significantly, enabling more efficient learning processes.
The refinement stage in RL involves more detailed simulations or deeper analysis through techniques like Monte Carlo tree search (MCTS) or temporal difference learning, which refine the policy and value estimates to optimize long-term rewards. This step is crucial for fine-tuning the strategy to achieve optimal performance, particularly in complex environments where numerous possible actions and outcomes exist. RL's application of FRP is critical in scenarios requiring both quick decision-making and high accuracy, such as in autonomous vehicles and gaming.
Mixture of Experts
The mixture of experts (MoE) is a machine learning paradigm that incorporates FRP by dividing a complex problem into simpler, manageable sub-tasks, each handled by a specialized expert. In the filtering stage, a gating mechanism—acting as a filter that determines the most suitable expert for each specific part of the input data based on the data's characteristics. This stage is critical as it allows the system to allocate resources more efficiently by engaging only the most relevant experts for each task.
During the refinement stage, each chosen expert applies its specialized knowledge to process the input more thoroughly. This approach enhances the overall system's performance by combining the strengths of various experts tailored to different aspects of the data. The refinement ensures that each segment of the input is processed optimally, leading to improved accuracy and adaptability of the model across diverse scenarios. MoE models are particularly effective in tasks where different types of expertise are beneficial, such as in complex decision-making systems and large-scale classification problems.
Cascading Classifiers
Cascading classifiers in computer vision exemplify the Filter and Refine Principle (FRP) by employing a hierarchical arrangement of classifiers, each increasing in complexity and precision. Initial classifiers quickly filter out clearly irrelevant data, significantly reducing the dataset's volume for processing by subsequent stages. This early filtering allows for a rapid reduction in data size, streamlining the process.
As the dataset moves through each stage of the cascade, the remaining data becomes progressively smaller and consists of increasingly complex cases. Later classifiers refine the decisions by focusing intensively on these challenging cases, ensuring high accuracy while minimizing computational demands. This technique is especially effective in real-time scenarios such as face detection in video streams, where fast processing is critical. The cascading approach not only accelerates processing speeds but also enhances the system's capability to manage complex tasks efficiently under tight resource constraints.
Query Processing
Query processing in large databases and information retrieval systems frequently employ the FRP to handle vast amounts of data efficiently. Initially, a query processor filters data through mechanisms like query optimization, where queries are reformulated and simplified to reduce the computational cost. This process might involve selecting the most efficient query plan or utilizing statistical estimates to quickly prune large data sections that do not match the query criteria. This initial filtering stage is crucial to ensure that the system uses its resources effectively, preparing the ground for more detailed examination
In the refinement stage of query processing, the system performs a detailed execution of the chosen query plan. This involves accessing the actual data, applying more complex filters, and performing operations such as joins, aggregations, and sorts on the narrowed-down data set. This stage refines the results to meet the query's exact specifications, ensuring high precision and relevance. This dual-stage processing is fundamental in environments with large, complex data sets where performance and accuracy are critical, such as in online transaction processing systems and large-scale analytical queries.
History and Development
The principles underlying FRP can be traced back to early efforts in optimizing database systems. The principle is the main optimization strategy of indices, where indices serve as a means to retrieve a subset of data quickly without scanning a large portion of the database, and do a thorough check on the subset of data upon retrieval. The core idea is to reduce both disk I/O and computational cost. The principle is used in query processing and data intensive applications. For example, in Jack A. Orenstein's 1986 SIGMOD paper, “Spatial Query Processing in an Object-Oriented Database System,” proposed concepts related to FRP as the study explores efficient methods for spatial query processing within databases.
Further formalization of FRP was explicitly proposed in the 1999 paper by Ho-Hyun Park et al., “Early Separation of Filter and Refinement Steps in Spatial Query Optimization”.
This paper systematically applied the FRP strategy to enhance spatial query optimization, marking a significant point in the history of FRP's application in computational tasks.
The Filter and Refine Principle (FRP) has been a cornerstone in the evolution of computational systems. Its origins can be traced back to early computing practices where efficiency and resource management were critical, leading to the development of algorithms and systems that implicitly used FRP-like strategies. Over the decades, as computational resources expanded and the complexity of tasks increased, the need for formalizing such a principle became evident. This led to a more structured application of FRP across various domains, from databases and operating systems to network design and machine learning, where trade-offs between speed and accuracy are continuously managed.
FRP as a distinct principle has been increasingly cited in academic literature and industry practices as systems face growing volumes of data and demand for real-time processing. This recognition is a testament to the evolving nature of technology and the need for frameworks that can adaptively manage the dual demands of efficiency and precision. Today, FRP is integral to the design of scalable systems that require handling large datasets efficiently, ensuring that it remains relevant in the era of big data, artificial intelligence, and beyond.
References
External links
Early Separation of Filter and Refinement Steps in Spatial Query Optimization in Proceedings. 6th International Conference on Advanced Systems for Advanced Applications. IEEE, 1999.
Fast Filter-and-refine Algorithms for Subsequence Selection in Proceedings International Database Engineering and Applications Symposium. IEEE, 2002.
Filter and Refine Strategy: Wood, J. (2017). Encyclopedia of GIS. Springer, Cham.
Computer science | Filter and refine | [
"Technology"
] | 1,730 | [
"Computer science"
] |
76,807,453 | https://en.wikipedia.org/wiki/Mass%20injection%20flow | Mass injection flow ( Limbach Flow) refers to inviscid, adiabatic flow through a constant area duct where the effect of mass addition is considered. For this model, the duct area remains constant, the flow is assumed to be steady and one-dimensional, and mass is added within the duct. Because the flow is adiabatic, unlike in Rayleigh flow, the stagnation temperature is a constant. Compressibility effects often come into consideration, though this flow model also applies to incompressible flow.
For supersonic flow (an upstream Mach number greater than 1), deceleration occurs with mass addition to the duct and the flow can become choked. Conversely, for subsonic flow (an upstream Mach number less than 1), acceleration occurs and the flow can become choked given sufficient mass addition. Therefore, mass addition will cause both supersonic and subsonic Mach numbers to approach Mach 1, resulting in choked flow.
Theory
The 1D mass injection flow model begins with a mass-velocity relation derived for mass injection into a steady, adiabatic, frictionless, constant area flow of calorically perfect gas:
where represents a mass flux, . This expression describes how velocity will change with a change in mass flux (i.e. how a change in mass flux drives a change in velocity ). From this relation, two distinct modes of behavior are seen:
When flow is subsonic () the quantity is negative, so the right-hand side of the equation becomes positive. This indicates that increasing mass flux will increase subsonic flow velocity toward Mach 1.
When flow is supersonic () the quantity is positive, so the right-hand side of the equation becomes negative. This indicates that increasing mass flux will decrease supersonic flow velocity towards Mach 1.
From the mass-velocity relation, an explicit mass-Mach relation may be derived:
Derivations
Although Fanno flow and Rayleigh flow are covered in detail in many textbooks, mass injection flow is not. For this reason, derivations of fundamental mass flow properties are given here. In the following derivations, the constant is used to denote the specific gas constant (i.e. ).
Mass-Velocity Relation
We begin by establishing a relationship between the differential enthalpy, pressure, and density of a calorically perfect gas:
From the adiabatic energy equation () we find:
Substituting the enthalpy-pressure-density relation () into the adiabatic energy relation () yields
Next, we find a relationship between differential density, mass flux (), and velocity:
Substituting the density-mass-velocity relation () into the modified energy relation () yields
Substituting the 1D steady flow momentum conservation equation (see also the Euler equations) of the form into () yields
From the ideal gas law we find,
and from the definition of a calorically perfect gas we find,
Substituting expressions () and () into the combined equation () yields
Using the speed of sound in an ideal gas () and the definition of the Mach number () yields
This is the mass-velocity relationship for mass injection into a steady, adiabatic, frictionless, constant area flow of calorically perfect gas.
Mass-Mach Relation
To find a relationship between differential mass and Mach number, we will find an expression for solely in terms of the Mach number, . We can then substitute this expression into the mass-velocity relation to yield a mass-Mach relation. We begin by relating differential velocity, mach number, and speed of sound:
We can now re-express in terms of :
Substituting () into () yields,
We can now re-express in terms of :
By substituting () into (), we can create an expression completely in terms of and . Performing this substitution and solving for yields,
Finally, expression () for in terms of may be substituted directly into the mass-velocity relation ():
This is the mass-Mach relationship for mass injection into a steady, adiabatic, frictionless, constant area flow of calorically perfect gas.
See Also
Fanno flow
Rayleigh flow
Compressible flow
Choked flow
Fanno flow
Inviscid flow
Adiabatic process
Gas dynamics
References
Fluid mechanics
Fluid dynamics
Aerodynamics
Thermodynamic processes | Mass injection flow | [
"Physics",
"Chemistry",
"Engineering"
] | 874 | [
"Chemical engineering",
"Thermodynamic processes",
"Aerodynamics",
"Civil engineering",
"Thermodynamics",
"Aerospace engineering",
"Piping",
"Fluid mechanics",
"Fluid dynamics"
] |
76,808,462 | https://en.wikipedia.org/wiki/Supersilver%20ratio | In mathematics, the supersilver ratio is a geometrical proportion close to . Its true value is the real solution of the equation
The name supersilver ratio results from analogy with the silver ratio, the positive solution of the equation , and the supergolden ratio.
Definition
Two quantities are in the supersilver ratio-squared if
The ratio is here denoted
Based on this definition, one has
It follows that the supersilver ratio is found as the unique real solution of the cubic equation
The decimal expansion of the root begins as .
The minimal polynomial for the reciprocal root is the depressed cubic thus the simplest solution with Cardano's formula,
or, using the hyperbolic sine,
is the superstable fixed point of the iteration
Rewrite the minimal polynomial as , then the iteration results in the continued radical
Dividing the defining trinomial by one obtains , and the conjugate elements of are
with and
Properties
The growth rate of the average value of the n-th term of a random Fibonacci sequence is .
The defining equation can be written
The supersilver ratio can be expressed in terms of itself as fractions
Similarly as the infinite geometric series
in comparison to the silver ratio identities
For every integer one has
From this an infinite number of further relations can be found.
Continued fraction pattern of a few low powers
The supersilver ratio is a Pisot number. Because the absolute value of the algebraic conjugates is smaller than 1, powers of generate almost integers. For example: After ten rotation steps the phases of the inward spiraling conjugate pair – initially close to – nearly align with the imaginary axis.
The minimal polynomial of the supersilver ratio has discriminant and factors into the imaginary quadratic field has class number Thus, the Hilbert class field of can be formed by adjoining
With argument a generator for the ring of integers of , the real root of the Hilbert class polynomial is given by
The Weber-Ramanujan class invariant is approximated with error by
while its true value is the single real root of the polynomial
The elliptic integral singular value has closed form expression
(which is less than 1/294 the eccentricity of the orbit of Venus).
Third-order Pell sequences
These numbers are related to the supersilver ratio as the Pell numbers and Pell-Lucas numbers are to the silver ratio.
The fundamental sequence is defined by the third-order recurrence relation
with initial values
The first few terms are 1, 2, 4, 9, 20, 44, 97, 214, 472, 1041, 2296, 5064,... .
The limit ratio between consecutive terms is the supersilver ratio.
The first 8 indices n for which is prime are n = 1, 6, 21, 114, 117, 849, 2418, 6144. The last number has 2111 decimal digits.
The sequence can be extended to negative indices using
The generating function of the sequence is given by
The third-order Pell numbers are related to sums of binomial coefficients by
.
The characteristic equation of the recurrence is If the three solutions are real root and conjugate pair and , the supersilver numbers can be computed with the Binet formula
with real and conjugates and the roots of
Since and the number is the nearest integer to with and
Coefficients result in the Binet formula for the related sequence
The first few terms are 3, 2, 4, 11, 24, 52, 115, 254, 560, 1235, 2724, 6008,... .
This third-order Pell-Lucas sequence has the Fermat property: if p is prime, The converse does not hold, but the small number of odd pseudoprimes makes the sequence special. The 14 odd composite numbers below to pass the test are n = 3, 5, 5, 315, 99297, 222443, 418625, 9122185, 3257, 11889745, 20909625, 24299681, 64036831, 76917325.
The third-order Pell numbers are obtained as integral powers of a matrix with real eigenvalue
The trace of gives the above
Alternatively, can be interpreted as incidence matrix for a D0L Lindenmayer system on the alphabet with corresponding substitution rule
and initiator . The series of words produced by iterating the substitution have the property that the number of and are equal to successive third-order Pell numbers. The lengths of these words are given by
Associated to this string rewriting process is a compact set composed of self-similar tiles called the Rauzy fractal, that visualizes the combinatorial information contained in a multiple-generation three-letter sequence.
Supersilver rectangle
Given a rectangle of height , length and diagonal length The triangles on the diagonal have altitudes each perpendicular foot divides the diagonal in ratio .
On the right-hand side, cut off a square of side length and mark the intersection with the falling diagonal. The remaining rectangle now has aspect ratio (according to ). Divide the original rectangle into four parts by a second, horizontal cut passing through the intersection point.
The parent supersilver rectangle and the two scaled copies along the diagonal have linear sizes in the ratios The areas of the rectangles opposite the diagonal are both equal to with aspect ratios (below) and (above).
If the diagram is further subdivided by perpendicular lines through the feet of the altitudes, the lengths of the diagonal and its seven distinct subsections are in ratios
Supersilver spiral
A supersilver spiral is a logarithmic spiral that gets wider by a factor of for every quarter turn. It is described by the polar equation with initial radius and parameter If drawn on a supersilver rectangle, the spiral has its pole at the foot of altitude of a triangle on the diagonal and passes through vertices of rectangles with aspect ratio which are perpendicularly aligned and successively scaled by a factor
See also
Solutions of equations similar to :
Silver ratio – the only positive solution of the equation
Golden ratio – the only positive solution of the equation
Supergolden ratio – the only real solution of the equation
References
Cubic irrational numbers
Mathematical constants
History of geometry
Integer sequences | Supersilver ratio | [
"Mathematics"
] | 1,284 | [
"Sequences and series",
"Integer sequences",
"Mathematical structures",
"History of geometry",
"Recreational mathematics",
"Mathematical objects",
"Combinatorics",
"nan",
"Geometry",
"Mathematical constants",
"Numbers",
"Number theory"
] |
69,377,164 | https://en.wikipedia.org/wiki/Nordic%20Rheology%20Society | The Nordic Rheology Society (NRS) is a professional organization that promotes and propagates rheology in the Nordic countries and beyond. The NRS provides a forum for academic and industrial researchers to discuss their ideas and to present their research.
History
The predecessor of the NRS, Swedish Society of Rheology, was founded in 1956 as a part of the Swedish National Committee for Mechanics. Erik Forslind was elected as the first president, Hilding Faxén as vice-president and Josef Kubát as secretary. The Swedish Society of Rheology became a full member of the International Committee on Rheology (ICR) in 1969, and it organized the VIIth International Congress on Rheology in Gothenburg in 1976.
The name Swedish Society of Rheology was changed to Nordic Rheology Society in 1992 with the aim of increased Nordic cooperation. The first president of the NRS was Carl Klason. Since 1992, the NRS has annually organized the Nordic Rheology Conference. In addition, the NRS has hosted the Annual European Rheology Conference (AERC) in 2010 (Gothenburg), 2017 (Copenhagen) and 2021 (online). During the COVID-19 pandemic, the NRS pioneered the use of avatar-based virtual event platforms in scientific conferences.
Conferences and publications
The annual scientific meeting of the NRS, Nordic Rheology Conference (NRC), circulates between the Nordic countries. It typically features scientific presentations from various fields of rheology, a technical exhibition, a rheology short course, as well as social program. The Annual Transactions of the Nordic Rheology Society is the official publication of the NRS and it features papers presented at NRCs.
Furthermore, the NRS occasionally organizes local rheology seminars in the Nordic countries.
Awards
The NRS presents two awards for outstanding rheologists who are active in the Nordic countries:
The Carl Klason Rheology Award
The Young Rheologists Rheology Award
References
External links
NRS website
Rheology
Scientific organizations established in 1992
1992 establishments in Sweden
Scientific organizations based in Sweden | Nordic Rheology Society | [
"Chemistry"
] | 435 | [
"Rheology",
"Fluid dynamics"
] |
69,378,275 | https://en.wikipedia.org/wiki/Flag%20algebra | Flag algebras are an important computational tool in the field of graph theory which have a wide range of applications in homomorphism density and related topics. Roughly, they formalize the notion of adding and multiplying homomorphism densities and set up a framework to solve graph homomorphism inequalities with computers by reducing them to semidefinite programming problems. Originally introduced by Alexander Razborov in a 2007 paper, the method has since come to solve numerous difficult, previously unresolved graph theoretic questions. These include the question regarding the region of feasible edge density, triangle density pairs and the maximum number of pentagons in triangle free graphs.
Motivation
The motivation of the theory of flag algebras is credited to John Adrian Bondy and his work on the Caccetta-Haggkvist conjecture, where he illustrated his main ideas via a graph homomorphism flavored proof to Mantel's Theorem. This proof is an adaptation on the traditional proof of Mantel via double counting, except phrased in terms of graph homomorphism densities and shows how much information can be encoded with just density relationships.
Theorem (Mantel): The edge density in a triangle-free graph is at most . In other words,
As the graph is triangle-free, among 3 vertices in , they can either form an independent set, a single induced edge , or a path of length 2 . Denoting as the induced density of a subgraph in , double counting gives:
Intuitively, since a just consists of two s connected together, and there are 3 ways to label the common vertex among a set of 3 points. In fact, this can be rigorously proven by double counting the number of induced s. Letting denote the number of vertices of , we have:
where is the path of length 2 with its middle vertex labeled, and represents the density of s subject to the constraint that the labeled vertex is used, and that is counted as a proper induced subgraph only when its labeled vertex coincides with . Now, note that since the probability of choosing two s where the unlabeled vertices coincide is small (to be rigorous, a limit as should be taken, so acts as a limit function on a sequence of larger and larger graphs . This idea will be important for the actual definition of flag algebras.)
To finish, apply the Cauchy–Schwarz inequality to get
Plugging this back into our original relation proves what was hypothesized intuitively. Finally, note that so
The important ideas from this proof which will be generalized in the theory of flag algebras are substitutions such as , the use of labeled graph densities, considering only the "limit case" of the densities, and applying Cauchy at the end to get a meaningful result.
Definition
Fix a collection of forbidden subgraphs and consider the set of graphs of -free graphs. Now, define a type of size to be a graph with labeled vertices . The type of size 0 is typically denoted as .
First, we define a -flag, a partially labeled graph which will be crucial for the theory of flag algebras:
Definition: A -flag is a pair where is an underlying, unlabeled, -free graph, while defines a labeled graph embedding of onto the vertices . Denote the set of -flags to be and the set of -flags of size to be . As an example, from the proof of Mantel's Theorem above is a -flag where is a type of size 1 corresponding to a single vertex.
For -flags satisfying , we can define the density of the -flags onto the underlying graph in the following way:
Definition: The density of the -flags in is defined to be the probability of successfully randomly embedding into such that they are nonintersecting on and are all labeled in the exact same way as on .
More precisely, choose pairwise disjoint at random and define to be the probability that the -flag is isomorphic to for all .
Note that, when embedding into , where are -flags, it can be done by first embedding into a -flag of size and then embedding into , which gives the formula: . Extending this to sets of -flags gives the Chain Rule:
Theorem (Chain Rule): If are -flags, are naturals such that fit in , fit in a -flag of size , and a -flag of size combined with fit in , then .
Recall that the previous proof for Mantel's involved linear combinations of terms of the form . The relevant ideas were slightly imprecise with letting tend to infinity, but explicitly there is a sequence such that converges to some for all , where is called a limit functional. Thus, all references to really refer to the limit functional. Now, graph homomorphism inequalities can be written as linear combinations of with different s, but it would be convenient to express them as a single term. This motivates defining , the set of formal linear combinations of -flags over , and now can be extended to a linear function over .
However, using the full space is wasteful when investigating just limit functionals, since there exist nontrivial relations between densities of certain -flags. In particular, the Chain Rule shows that
is always true. Rather than dealing with all of these elements of the kernel, let the set of expressions of the above form (i.e. those obtained from Chain Rule with a single -flag) as and quotient them out in our final analysis. These ideas combine to form the definition for a flag algebra:
Definition (Flag Algebras): A flag algebra is defined on the space of linear combinations of -flags equipped with bilinear operator for and any natural such that fit in a -flag of size , extending the operator linearly to .
It remains to check that the choice of does not matter for a pair provided it is large enough (this can be proven with Chain Rule) as well as that if then , meaning that the operator respects the quotient and thus forms a well-defined algebra on the desired space.
One important result of this definition for the operator is that multiplication is respected on limit functionals. In particular, for a limit functional , the identity holds true. For example, it was shown that in our proof for Mantel's, and this result is just a corollary of this statement. More generally, the fact that is multiplicative means that all limit functionals are algebra homomorphisms between and .
The downward operator
The definition above provides a framework for dealing with -flags, which are partially labeled graphs. However, most of the time, unlabeled graphs, or -flags, are of greatest interest. To get from the former to the latter, define the downward operator.
The downward operator is defined in the most natural way: given a -flag , let to be the -flag resulting from forgetting the labels assigned to . Now, to define a natural mapping between -flags and unlabeled graphs, let be the probability that an injective map taken at random has image isomorphic to , and define . Extending linearly to gives a valid linear map which sends combinations of -flags to combinations of unlabeled ones.
The most important result regarding is its averaging properties. In particular, fix a -flag and unlabeled graph with , then choosing an embedding of on at random defines random variable . It can be shown that
Optimization with flag algebras
All linear functionals, are algebra homomorphisms . Furthermore, by definition, for any -flag since represents a density limit. Thus, say that a homomorphism is positive if and only if , and let be the set of positive homomorphisms. One can show that the set of limit functionals is exactly the set of positive homomorphisms , so it suffices to understand the latter definition of the set.
In order for a linear combination to yield a valid graph homomorphism inequality, it needs to be nonnegative over all possible linear functionals, which will then imply that it is true for all graphs. With this in mind, define the semantic cone of type , a set such that
Once again, is the case of most interest, which corresponds to the case of unlabeled graphs. However, the downward operator has the property of mapping to , and it can be shown that the image of under is a subset of , meaning that any results on the type semantic cone readily generalize to unlabeled graphs as well.
Just by naively manipulating elements of , numerous elements of the semantic cone can be generated. For example, since elements of are nonnegative for -flags, any conical combination of elements of will yield an element of . Perhaps more non-trivially, any conical combination of squares of elements of will also yield an element of the semantic cone.
Though one can find squares of flags which sum to nontrivial results manually, it is often simpler to automate the process. In particular, it is possible to adapt the ideas in sum-of-squares optimization for polynomials to flag algebras. Define the degree of a vector to be the largest flag with nonzero coefficient in the expansion of , and let the degree of to be the minimum degree of a vector over all choices in . Also, define as the canonical embedding sending to itself for all . These definitions give rise to the following flag-algebra analogue:
Theorem: Given , , then there exist for some if and only if there is a positive semidefinite matrix such that .
With this theorem, graph homomorphism problems can now be relaxed into semidefinite programming ones which can be solved via computer. For example, Mantel's Theorem can be rephrased as finding the smallest such that . As is poorly understood, it is difficult to make progress on the question in this form, but note that conic combinations of -flags and squares of vectors lie in , so instead take a semidefinite relaxation. In particular, minimize under the constraint that where is a conic combination of -flags and is positive semi-definite. This new optimization problem can be transformed into a semidefinite-programming problem which is then solvable with standard algorithms.
Generalizations
The method of flag algebras readily generalizes to numerous graph-like constructs. As Razborov wrote in his original paper, flags can be described with finite model theory instead. Instead of graphs, models of some nondegenerate universal first-order theory with equality in a finite relational signature with only predicate symbols can be used. A model , which replaces our previous notion of a graph, has ground set , whose elements are called vertices.
Now, defining sub-models and model embeddings in an analogous way to subgraphs and graph embeddings, all of the definitions and theorems above can be nearly directly translated into the language of model theory. The fact that the theory of flag algebras generalizes well means that it can be used not only to solve problems in simple graphs, but also similar constructs such as, but not limited to, directed graphs and hypergraphs.
References
Graph theory | Flag algebra | [
"Mathematics"
] | 2,281 | [
"Discrete mathematics",
"Mathematical relations",
"Graph theory",
"Combinatorics"
] |
69,378,663 | https://en.wikipedia.org/wiki/Ministry%20of%20Energy%20%28Chile%29 | The Ministry of Energy () is an entity created during the late part of the first presidency of Michelle Bachelet (2006−2010) after the releasing of the N°20.402 Decrete of Law on 1 February 2010.
Since that date, the current minister was separated from the Ministry of Mining. Its current minister is Diego Pardow Lorenzo.
List of representatives
References
External links
Government ministries of Chile | Ministry of Energy (Chile) | [
"Engineering"
] | 86 | [
"Energy organizations",
"Energy ministries"
] |
69,378,928 | https://en.wikipedia.org/wiki/Cytosis%20%28board%20game%29 | Cytosis is a cell biology worker placement board game designed by John Coveyou and published in 2017 by Genius Games. The game's development was funded via a crowdfunding campaign on Kickstarter.
Gameplay
The objective of the game is to ensure the health of a human cell by managing its operations. The board represents a cell in which are located various organelles that are sites of player actions. Around the edge of the board is a scoring track. There are coloured cubes representing various macromolecules within the cell: carbohydrates (green), lipids (yellow), messenger RNA (mRNA, black), and proteins (red). The sets of cards are split into Cell Component cards, Event cards, and Goal cards.
The cards are separated by type and shuffled, then four Cell Component cards are placed on the appropriate area of the game board, three to five randomly selected Goal cards are placed at the top of the game board, and players place one of their tokens at the zero space of the scoring track. The starting player receives two adenosine triphosphate (ATP) tokens, and each subsequent player one more ATP token than the player preceding them. Each player also selects to keep one of the three Cell Component cards that were dealt to them, shuffling the others into the draw pile.
Each turn, a player places their flask token on a chosen organelle and executes the prescribed action. These actions enable the player to collect resources such as carbohydrates or ATP, or to acquire Cell Component cards. This requires multiple steps and multiple turns to simulate the process of protein synthesis.
Players acquire health points by completing the actions listed on Cell Component cards, such as assembling enzymes and hormones or hormone receptors. These are then deployed to defend the cell from viral infection. Health points are the game's victory points.
Expansion
The Virus expansion set includes additional Cell Component, Event, and Goal cards, and also includes pink antibody cubes, dice, and player mats.
Reception
The game has been endorsed by the Journal of Cell Science.
Alex Rosenwald, in a review for Board Game Quest, stated that the concept of protein synthesis "shines through in all facets of gameplay", with the game mechanics and organelle cell functions aligning into an "immersive experience of creating and transporting various chemicals in and out of the cells". He also stated that the game's basis in science is "hit-or-miss" amongst players, with "no real grey area for ambivalence".
In a review for Meeple Mountain, David McMillan stated the gameplay distracts players from the background educational aspect of the game, and that it "performs brilliantly" in terms of both appeal and engagement.
References
Further reading
External links
Cytosis at Genius Games
Board games introduced in 2017
Worker placement board games
Cell biology
Biology-themed board games | Cytosis (board game) | [
"Biology"
] | 592 | [
"Cell biology"
] |
69,380,218 | https://en.wikipedia.org/wiki/Hypergraph%20regularity%20method | In mathematics, the hypergraph regularity method is a powerful tool in extremal graph theory that refers to the combined application of the hypergraph regularity lemma and the associated counting lemma. It is a generalization of the graph regularity method, which refers to the use of Szemerédi's regularity and counting lemmas.
Very informally, the hypergraph regularity lemma decomposes any given -uniform hypergraph into a random-like object with bounded parts (with an appropriate boundedness and randomness notions) that is usually easier to work with. On the other hand, the hypergraph counting lemma estimates the number of hypergraphs of a given isomorphism class in some collections of the random-like parts. This is an extension of Szemerédi's regularity lemma that partitions any given graph into bounded number parts such that edges between the parts behave almost randomly. Similarly, the hypergraph counting lemma is a generalization of the graph counting lemma that estimates number of copies of a fixed graph as a subgraph of a larger graph.
There are several distinct formulations of the method, all of which imply the hypergraph removal lemma and a number of other powerful results, such as Szemerédi's theorem, as well as some of its multidimensional extensions. The following formulations are due to V. Rödl, B. Nagle, J. Skokan, M. Schacht, and Y. Kohayakawa, for alternative versions see Tao (2006), and Gowers (2007).
Definitions
In order to state the hypergraph regularity and counting lemmas formally, we need to define several rather technical terms to formalize appropriate notions of pseudo-randomness (random-likeness) and boundedness, as well as to describe the random-like blocks and partitions.
Notation
denotes a -uniform clique on vertices.
is an -partite -graph on vertex partition .
is the family of all -element vertex sets that span the clique in . In particular, is a complete -partite -graph.
The following defines an important notion of relative density, which roughly describes the fraction of -edges spanned by -edges that are in the hypergraph. For example, when , the quantity is equal to the fraction of triangles formed by 2-edges in the subhypergraph that are 3-edges. Definition [Relative density]. For , fix some classes of with . Suppose is an integer. Let be a subhypergraph of the induced -partite graph . Define the relative density .What follows is the appropriate notion of pseudorandomness that the regularity method will use. Informally, by this concept of regularity, -edges () have some control over -edges (). More precisely, this defines a setting where density of edges in large subhypergraphs is roughly the same as one would expect based on the relative density alone. Formally,Definition [()-regularity]. Suppose are positive real numbers and is an integer. is ()-regular with respect to if for any choice of classes and any collection of subhypergraphs of satisfying we have .Roughly speaking, the following describes the pseudorandom blocks into which the hypergraph regularity lemma decomposes any large enough hypergraph. In Szemerédi regularity, 2-edges are regularized versus 1-edges (vertices). In this generalized notion, -edges are regularized versus -edges for all . More precisely, this defines a notion of regular hypergraph called -complex, in which existence of -edge implies existence of all underlying -edges, as well as their relative regularity. For example, if is a 3-edge then ,, and are 2-edges in the complex. Moreover, the density of 3-edges over all possible triangles made by 2-edges is roughly the same in every collection of subhypergraphs.Definition [-regular -complex]. An -complex is a system of -partite graphs satisfying . Given vectors of positive real numbers , , and an integer , we say -complex is -regular if
For each , is -regular with density .
For each , is ()-regular with respect to .The following describes the equitable partition that the hypergraph regularity lemma will induce. A -equitable family of partition is a sequence of partitions of 1-edges (vertices), 2-edges (pairs), 3-edges (triples), etc. This is an important distinction from the partition obtained by Szemerédi's regularity lemma, where only vertices are being partitioned. In fact, Gowers demonstrated that solely vertex partition can not give a sufficiently strong notion of regularity to imply Hypergraph counting lemma. Definition [-equitable partition]. Let be a real number, be an integer, and , be vectors of positive reals. Let be a vector of positive integers and be an -element vertex set. We say that a family of partitions on is -equitable if it satisfies the following:
is equitable vertex partition of . That is .
partitions so that if and then is partitioned into at most parts, all of which are members .
For all but at most -tuples there is unique -regular -complex such that has as members different partition classes from and .Finally, the following defines what it means for a -uniform hypergraph to be regular with respect to a partition. In particular, this is the main definition that describes the output of hypergraph regularity lemma below.Definition [Regularity with respect to a partition]. We say that a -graph is -regular with respect to a family of partitions if all but at most edges of have the property that and if is unique -complex for which , then is regular with respect to .
Statements
Hypergraph regularity lemma
For all positive real , , and functions , for there exists and so that the following holds. For any -uniform hypergraph on vertices, there exists a family of partitions and a vector so that, for and where for all , the following holds.
is a -equitable family of partitions and for every .
is regular with respect to .
Hypergraph counting lemma
For all integers the following holds: and there are integers and so that, with , , and ,
if is a -regular complex with vertex partition and , then
.
Applications
The main application through which most others follow is the hypergraph removal lemma, which roughly states that given fixed and large -uniform hypergraphs, if contains few copies of , then one can delete few hyperedges in to eliminate all of the copies of . To state it more formally,
Hypergraph removal lemma
For all and every , there exists and so that the following holds. Suppose is a -uniform hypergraph on vertices and is that on vertices. If contains at most copies of , then one can delete hyperedges in to make it -free. One of the original motivations for graph regularity method was to prove Szemerédi's theorem, which states that every dense subset of contains an arithmetic progression of arbitrary length. In fact, by a relatively simple application of the triangle removal lemma, one can prove that every dense subset of contains an arithmetic progression of length 3.
The hypergraph regularity method and hypergraph removal lemma can prove high-dimensional and ring analogues of density version of Szemerédi's theorems, originally proved by Furstenberg and Katznelson. In fact, this approach yields first quantitative bounds for the theorems.
This theorem roughly implies that any dense subset of contains any finite pattern of . The case when and the pattern is arithmetic progression of length some length is equivalent to Szemerédi's theorem. Furstenberg and Katznelson Theorem
Source:
Let be a finite subset of and let be given. Then there exists a finite subset such that every with contains a homothetic copy of . (i.e. set of form , for some and )
Moreover, if for some , then there exists such that has this property for all .Another possible generalization that can be proven by the removal lemma is when the dimension is allowed to grow. Tengan, Tokushige, Rödl, and Schacht Theorem
Let be a finite ring. For every , there exists such that, for , any subset with contains a coset of an isomorphic copy of (as a left -module).
In other words, there are some such that , where , is an injection.
References
Graph theory | Hypergraph regularity method | [
"Mathematics"
] | 1,765 | [
"Discrete mathematics",
"Mathematical relations",
"Graph theory",
"Combinatorics"
] |
69,381,426 | https://en.wikipedia.org/wiki/Rho%20Octantis | Rho Octantis, Latinized from ρ Octantis, is a star located in the southern circumpolar constellation Octans. With an apparent magnitude of 5.57, its faintly visible to the naked eye under ideal conditions. The star is located 215 light years away from the Solar System, but is drifting closer with a radial velocity of .
Rho Octantis has a classification of A1/2 V, which states its a star with the traits of an A1 and A2 main-sequence star. It has nearly twice the mass of the Sun, and has a radius of 2.19 solar radii. The star radiates at a luminosity 21 times greater than the Sun from its photosphere at an effective temperature of , which gives it a white hue. Like many A-type stars, Rho Octantis rotates rapidly, with a projected rotational velocity of 128 km/s; it is 431 million years old. Rho Octantis has a common proper motion K0 companion 65.7” away.
References
Octantis, ρ
Octantis, 24
076996
5729
137333
A-type main-sequence stars
Durchmusterung objects
Octans | Rho Octantis | [
"Astronomy"
] | 253 | [
"Octans",
"Constellations"
] |
69,381,645 | https://en.wikipedia.org/wiki/Quasirandom%20group | In mathematics, a quasirandom group is a group that does not contain a large product-free subset. Such groups are precisely those without a small non-trivial irreducible representation. The namesake of these groups stems from their connection to graph theory: bipartite Cayley graphs over any subset of a quasirandom group are always bipartite quasirandom graphs.
Motivation
The notion of quasirandom groups arises when considering subsets of groups for which no two elements in the subset have a product in the subset; such subsets are termed product-free. László Babai and Vera Sós asked about the existence of a constant for which every finite group with order has a product-free subset with size at least . A well-known result of Paul Erdős about sum-free sets of integers can be used to prove that suffices for abelian groups, but it turns out that such a constant does not exist for non-abelian groups.
Both non-trivial lower and upper bounds are now known for the size of the largest product-free subset of a group with order . A lower bound of can be proved by taking a large subset of a union of sufficiently many cosets, and an upper bound of is given by considering the projective special linear group for any prime . In the process of proving the upper bound, Timothy Gowers defined the notion of a quasirandom group to encapsulate the product-free condition and proved equivalences involving quasirandomness in graph theory.
Graph quasirandomness
Formally, it does not make sense to talk about whether or not a single group is quasirandom. The strict definition of quasirandomness will apply to sequences of groups, but first bipartite graph quasirandomness must be defined. The motivation for considering sequences of groups stems from its connections with graphons, which are defined as limits of graphs in a certain sense.
Fix a real number A sequence of bipartite graphs (here is allowed to skip integers as long as tends to infinity) with having vertices, vertex parts and , and edges is quasirandom if any of the following equivalent conditions hold:
For every bipartite graph with vertex parts and , the number of labeled copies of in with embedded in and embedded in is Here, the function is allowed to depend on
The number of closed, labeled walks of length 4 in starting in is
The number of edges between and is for any pair of subsets and
, where denotes the number of common neighbors of and
The largest eigenvalue of 's adjacency matrix is and all other eigenvalues have magnitude at most
It is a result of Chung–Graham–Wilson that each of the above conditions is equivalent. Such graphs are termed quasirandom because each condition asserts that the quantity being considered is approximately what one would expect if the bipartite graph was generated according to the Erdős–Rényi random graph model; that is, generated by including each possible edge between and independently with probability
Though quasirandomness can only be defined for sequences of graphs, a notion of -quasirandomness can be defined for a specific graph by allowing an error tolerance in any of the above definitions of graph quasirandomness. To be specific, given any of the equivalent definitions of quasirandomness, the term can be replaced by a small constant , and any graph satisfying that particular modified condition can be termed -quasirandom. It turns out that -quasirandomness under any condition is equivalent to -quasirandomness under any other condition for some absolute constant
The next step for defining group quasirandomness is the Cayley graph. Bipartite Cayley graphs give a way from translating quasirandomness in the graph-theoretic setting to the group-theoretic setting.
Given a finite group and a subset , the bipartite Cayley graph is the bipartite graph with vertex sets and , each labeled by elements of , whose edges are between vertices whose ratio is an element of
Definition
With the tools defined above, one can now define group quasirandomness. A sequence of groups with (again, is allowed to skip integers) is quasirandom if for every real number and choice of subsets with , the sequence of graphs is quasirandom.
Though quasirandomness can only be defined for sequences of groups, the concept of -quasirandomness for specific groups can be extended to groups using the definition of -quasirandomness for specific graphs.
Properties
As proved by Gowers, group quasirandomness turns out to be equivalent to a number of different conditions.
To be precise, given a sequence of groups , the following are equivalent:
is quasirandom; that is, all sequences of Cayley graphs defined by are quasirandom.
The dimension of the smallest non-trivial representation of is unbounded.
The size of the largest product-free subset of is
The size of the smallest non-trivial quotient of is unbounded.
Cayley graphs generated from pseudorandom groups have strong mixing properties; that is, is a bipartite -graph for some tending to zero as tends to infinity. (Recall that an graph is a graph with vertices, each with degree , whose adjacency matrix has a second largest eigenvalue of at most )
In fact, it can be shown that for any -quasirandom group , the number of solutions to with , , and is approximately equal to what one might expect if was chosen randomly; that is, approximately equal to This result follows from a direct application of the expander mixing lemma.
Examples
There are several notable families of quasirandom groups. In each case, the quasirandomness properties are most easily verified by checking the dimension of its smallest non-trivial representation.
The projective special linear groups for prime form a sequence of quasirandom groups, since a classic result of Frobenius states that its smallest non-trivial representation has dimension at least In fact, these groups are the groups with the largest known minimal non-trivial representation, as a function of group order.
The alternating groups are quasirandom, since its smallest non-trivial representation has dimension
Any sequence of non-cyclic simple groups with increasing order is quasirandom, since its smallest non-trivial representation has dimension at least , where is the order of the group.
References
Graph theory
Group theory | Quasirandom group | [
"Mathematics"
] | 1,312 | [
"Discrete mathematics",
"Graph theory",
"Combinatorics",
"Group theory",
"Fields of abstract algebra",
"Mathematical relations"
] |
69,381,702 | https://en.wikipedia.org/wiki/Ramsey-Tur%C3%A1n%20theory | Ramsey-Turán theory is a subfield of extremal graph theory. It studies common generalizations of Ramsey's theorem and Turán's theorem. In brief, Ramsey-Turán theory asks for the maximum number of edges a graph which satisfies constraints on its subgraphs and structure can have. The theory organizes many natural questions which arise in extremal graph theory. The first authors to formalize the central ideas of the theory were Erdős and Sós in 1969, though mathematicians had previously investigated many Ramsey-Turán-type problems.
Ramsey's theorem and Turán's theorem
Ramsey's theorem for two colors and the complete graph, proved in its original form in 1930, states that for any positive integer there exists an integer large enough that for any coloring of the edges of the complete graph using two colors has a monochoromatic copy of . More generally, for any graphs , there is a threshold such that if and the edges of are colored arbitrarily with colors, then for some there is a in the th color.
Turán's theorem, proved in 1941, characterizes the graph with the maximal number of edges on vertices which does not contain a . Specifically, the theorem states that for all positive integers , the number of edges of an -vertex graph which does not contain as a subgraph is at most and that the maximum is attained uniquely by the Turán graph .
Both of these classic results ask questions about how large a graph can be before it possesses a certain property. There is a notable stylistic difference, however. The extremal graph in Turán's theorem has a very strict structure, having a small chromatic number and containing a small number of large independent sets. On the other hand, the graph considered in Ramsey problems is the complete graph, which has large chromatic number and no nontrivial independent set. A natural way to combine these two kinds of problems is to ask the following question, posed by Andrásfai:
Problem 1: For a given positive integer , let be an -vertex graph not containing and having independence number . What is the maximum number of edges such a graph can have?
Essentially, this question asks for the answer to the Turán problem in a Ramsey setting; it restricts Turán's problem to a subset of graphs with less orderly, more randomlike structure. The following question combines the problems in the opposite direction:
Problem 2: Let be fixed graphs. What is the maximum number of edges an -edge colored graph on vertices can have under the condition that it does not contain an in the th color?
General problem
The backbone of Ramsey-Turán theory is the common generalization of the above problems.
Problem 3: Let be fixed graphs. Let be an -edge-colored -vertex graph satisfying (1) (2) the subgraph defined by the th color contains no . What is the maximum number of edges can have? We denote the maximum by .
Ramsey-Turán-type problems are special cases of problem 3. Many cases of this problem remain open, but several interesting cases have been resolved with precise asymptotic solutions.
Notable results
Problem 3 can be divided into three different cases, depending on the restriction on the independence number. There is the restriction-free case, where , which reduces to the classic Ramsey problem. There is the "intermediate" case, where for a fixed . Lastly, there is the case, which contains the richest problems.
The most basic nontrivial problem in the range is when and Erdős and Sós determined the asymptotic value of the Ramsey-Turán number in this situation in 1969: The case of the complete graph on an even number of vertices is much more challenging, and was resolved by Erdős, Hajnal, Sós and Szemerédi in 1983: Note that in both cases, the problem can be viewed as adding the extra condition to Turán's theorem that . In both cases, it can be seen that asymptotically, the effect is the same as if we had excluded instead of or .
References
Graph theory | Ramsey-Turán theory | [
"Mathematics"
] | 837 | [
"Mathematical relations",
"Graph theory",
"Extremal graph theory"
] |
69,381,990 | https://en.wikipedia.org/wiki/Puccinia%20porri | Puccinia porri (previously known as Puccinia allii) is a species of rust fungus that causes leek rust. It affects leek, garlic, onion, and chives, and usually appears as bright orange spots on infected plants.
Fungus
Puccinia porri is autoecious, meaning that all stages of its life cycle occur on the host plant. While P. porri and P. mixta were originally thought to be separate species, by 1984 they were all generally categorized under P. allii. The fungus causes leek rust, but it also affects garlic, onion, and chives. In 2016, Alistair McTaggart and colleagues used molecular phylogenetic analysis to sort out collections of fungi labeled as Puccinia allii occurring in Australia, and placed this name in synonymy with Puccinia porri.
Conditions for growth
Leek rust appears seasonally, starting in the middle of August. It develops more quickly in warmer weather, so conversely, cold spells can reduce the onset of symptoms. If a leek reaches maturation closer to winter, it is more susceptible to infection, whereas a leek that matures earlier in the fall must be wet to endure a heavy attack. According to the Royal Horticultural Society, there are no fungicides approved for use by amateur gardeners to combat leek rust. However, in practice there are different fungicides that are recommended for use in different countries, depending on the Allium crop. For example, in Ethiopia, the fungicides mancozeb, propiconazole, tebuconazole or azoxystrobin are approved for use to control the fungus. They will control the rust if sprayed on the plant at 10-day intervals.
Symptoms of infection
On leeks, P. porri manifests as bright orange or yellow pustules on the upper parts of the leaves, usually between veins. Sometimes, the pustules grow to network with each other and spread to the base of the leaf. The aeciospores are between 19 and 28 micrometers in diameter, with yellow walls 1 to 2 micrometers in length. The urediniospores are more elliptical in shape, with a major axis diameter of 22–32 micrometers and a minor axis diameter of 20–26 micrometers. The teliospores are also elliptical, with a major axis diameter of 28–45 micrometers and a minor axis diameter of 20–26 micrometers.
Economic damage
An infected leek's discolouring can cause it to lose market value, as there is an expectation the vegetables do not have visual defects or flaws. The infection can also slow and reduce the growth of the plant. In addition, Uma (1984) writes that P. porri has caused significant losses for garlic farmers in California, Israel, South Africa, and Brazil.
References
porri
Fungi described in 1809
Fungal plant pathogens and diseases
Fungi of Africa
Fungi of North America
Fungi of South America
Taxa named by James Sowerby
Fungus species | Puccinia porri | [
"Biology"
] | 621 | [
"Fungi",
"Fungus species"
] |
69,383,671 | https://en.wikipedia.org/wiki/Global%20catastrophe%20scenarios | Scenarios in which a global catastrophic risk creates harm have been widely discussed. Some sources of catastrophic risk are anthropogenic (caused by humans), such as global warming, environmental degradation, and nuclear war. Others are non-anthropogenic or natural, such as meteor impacts or supervolcanoes. The impact of these scenarios can vary widely, depending on the cause and the severity of the event, ranging from temporary economic disruption to human extinction. Many societal collapses have already happened throughout human history.
Anthropogenic
Experts at the Future of Humanity Institute at the University of Oxford and the Centre for the Study of Existential Risk at the University of Cambridge prioritize anthropogenic over natural risks due to their much greater estimated likelihood. They are especially concerned by, and consequently focus on, risks posed by advanced technology, such as artificial intelligence and biotechnology.
Artificial intelligence
The creators of a superintelligent entity could inadvertently give it goals that lead it to annihilate the human race. It has been suggested that if AI systems rapidly become super-intelligent, they may take unforeseen actions or out-compete humanity. According to philosopher Nick Bostrom, it is possible that the first super-intelligence to emerge would be able to bring about almost any possible outcome it valued, as well as to foil virtually any attempt to prevent it from achieving its objectives. Thus, even a super-intelligence indifferent to humanity could be dangerous if it perceived humans as an obstacle to unrelated goals. In Bostrom's book Superintelligence, he defines this as the control problem. Physicist Stephen Hawking, Microsoft founder Bill Gates, and SpaceX founder Elon Musk have echoed these concerns, with Hawking theorizing that such an AI could "spell the end of the human race".
In 2009, the Association for the Advancement of Artificial Intelligence (AAAI) hosted a conference to discuss whether computers and robots might be able to acquire any sort of autonomy, and how much these abilities might pose a threat or hazard. They noted that some robots have acquired various forms of semi-autonomy, including being able to find power sources on their own and being able to independently choose targets to attack with weapons. They also noted that some computer viruses can evade elimination and have achieved "cockroach intelligence". They noted that self-awareness, as depicted in science-fiction, is probably unlikely, but there are other potential hazards and pitfalls. Various media sources and scientific groups have noted separate trends in differing areas which might together result in greater robotic functionalities and autonomy, and which pose some inherent concerns.
A survey of AI experts estimated that the chance of human-level machine learning having an "extremely bad (e.g., human extinction)" long-term effect on humanity is 5%. A 2008 survey by the Future of Humanity Institute estimated a 5% probability of extinction by super-intelligence by 2100. Eliezer Yudkowsky believes risks from artificial intelligence are harder to predict than any other known risks due to bias from anthropomorphism. Since people base their judgments of artificial intelligence on their own experience, he claims they underestimate the potential power of AI.
Biotechnology
Biotechnology can pose a global catastrophic risk in the form of bioengineered organisms (viruses, bacteria, fungi, plants, or animals). In many cases the organism will be a pathogen of humans, livestock, crops, or other organisms we depend upon (e.g. pollinators or gut bacteria). However, any organism able to catastrophically disrupt ecosystem functions, e.g. highly competitive weeds, outcompeting essential crops, poses a biotechnology risk.
A biotechnology catastrophe may be caused by accidentally releasing a genetically engineered organism from controlled environments, by the planned release of such an organism which then turns out to have unforeseen and catastrophic interactions with essential natural or agro-ecosystems, or by intentional usage of biological agents in biological warfare or bioterrorism attacks. Pathogens may be intentionally or unintentionally genetically modified to change virulence and other characteristics. For example, a group of Australian researchers unintentionally changed characteristics of the mousepox virus while trying to develop a virus to sterilize rodents. The modified virus became highly lethal even in vaccinated and naturally resistant mice. The technological means to genetically modify virus characteristics are likely to become more widely available in the future if not properly regulated. In December 2024, a broad coalition of scientists warned that mirror life, organisms that use the mirror images of naturally occurring chiral biomolecules, should not be created because if it escapes into the environment, it would evade predation by natural organisms and compete against it for non-chiral nutrients.
Biological weapons, whether used in war or terrorism, could result in human extinction. Terrorist applications of biotechnology have historically been infrequent. To what extent this is due to a lack of capabilities or motivation is not resolved. However, given current development, more risk from novel, engineered pathogens is to be expected in the future. Exponential growth has been observed in the biotechnology sector, and Noun and Chyba predict that this will lead to major increases in biotechnological capabilities in the coming decades. They argue that risks from biological warfare and bioterrorism are distinct from nuclear and chemical threats because biological pathogens are easier to mass-produce and their production is hard to control (especially as the technological capabilities are becoming available even to individual users). In 2008, a survey by the Future of Humanity Institute estimated a 2% probability of extinction from engineered pandemics by 2100.
Noun and Chyba propose three categories of measures to reduce risks from biotechnology and natural pandemics: Regulation or prevention of potentially dangerous research, improved recognition of outbreaks, and developing facilities to mitigate disease outbreaks (e.g. better and/or more widely distributed vaccines).
Chemical weapons
By contrast with nuclear and biological weapons, chemical warfare, while able to create multiple local catastrophes, is unlikely to create a global one.
Choice to have fewer children
The world population may decline through a preference for fewer children. If developing world demographics are assumed to become developed world demographics, and if the latter are extrapolated, some projections suggest an extinction before the year 3000. John A. Leslie estimates that if the reproduction rate drops to the German or Japanese level the extinction date will be 2400. However, some models suggest the demographic transition may reverse itself due to evolutionary biology.
Climate change
Human-caused climate change has been driven by technology since the 19th century or earlier. Projections of future climate change suggest further global warming, sea level rise, and an increase in the frequency and severity of some extreme weather events and weather-related disasters. Effects of global warming include loss of biodiversity, stresses to existing food-producing systems, increased spread of known infectious diseases such as malaria, and rapid mutation of microorganisms.
A common belief is that the current climate crisis could spiral into human extinction. In November 2017, a statement by 15,364 scientists from 184 countries indicated that increasing levels of greenhouse gases from use of fossil fuels, human population growth, deforestation, and overuse of land for agricultural production, particularly by farming ruminants for meat consumption, are trending in ways that forecast an increase in human misery over coming decades. An October 2017 report published in The Lancet stated that toxic air, water, soils, and workplaces were collectively responsible for nine million deaths worldwide in 2015, particularly from air pollution which was linked to deaths by increasing susceptibility to non-infectious diseases, such as heart disease, stroke, and lung cancer. The report warned that the pollution crisis was exceeding "the envelope on the amount of pollution the Earth can carry" and "threatens the continuing survival of human societies". Carl Sagan and others have raised the prospect of extreme runaway global warming turning Earth into an uninhabitable Venus-like planet. Some scholars argue that much of the world would become uninhabitable under severe global warming, but even these scholars do not tend to argue that it would lead to complete human extinction, according to Kelsey Piper of Vox. All the IPCC scenarios, including the most pessimistic ones, predict temperatures compatible with human survival. The question of human extinction under "unlikely" outlier models is not generally addressed by the scientific literature. Factcheck.org judges that climate change fails to pose an established "existential risk", stating: "Scientists agree climate change does pose a threat to humans and ecosystems, but they do not envision that climate change will obliterate all people from the planet."
Cyberattack
Cyberattacks have the potential to destroy everything from personal data to electric grids. Christine Peterson, co-founder and past president of the Foresight Institute, believes a cyberattack on electric grids has the potential to be a catastrophic risk. She notes that little has been done to mitigate such risks, and that mitigation could take several decades of readjustment.
Environmental disaster
An environmental or ecological disaster, such as world crop failure and collapse of ecosystem services, could be induced by the present trends of overpopulation, economic development, and non-sustainable agriculture. Most environmental scenarios involve one or more of the following: Holocene extinction event, scarcity of water that could lead to approximately half the Earth's population being without safe drinking water, pollinator decline, overfishing, massive deforestation, desertification, climate change, or massive water pollution episodes. Detected in the early 21st century, a threat in this direction is colony collapse disorder, a phenomenon that might foreshadow the imminent extinction of the Western honeybee. As the bee plays a vital role in pollination, its extinction would severely disrupt the food chain.
An October 2017 report published in The Lancet stated that toxic air, water, soils, and workplaces were collectively responsible for nine million deaths worldwide in 2015, particularly from air pollution which was linked to deaths by increasing susceptibility to non-infectious diseases, such as heart disease, stroke, and lung cancer. The report warned that the pollution crisis was exceeding "the envelope on the amount of pollution the Earth can carry" and "threatens the continuing survival of human societies".
A May 2020 analysis published in Scientific Reports found that if deforestation and resource consumption continue at current rates they could culminate in a "catastrophic collapse in human population" and possibly "an irreversible collapse of our civilization" within the next several decades. The study says humanity should pass from a civilization dominated by the economy to a "cultural society" that "privileges the interest of the ecosystem above the individual interest of its components, but eventually in accordance with the overall communal interest." The authors also note that "while violent events, such as global war or natural catastrophic events, are of immediate concern to everyone, a relatively slow consumption of the planetary resources may be not perceived as strongly as a mortal danger for the human civilization."
Evolution
Some scenarios envision that humans could use genetic engineering or technological modifications to split into normal humans and a new species – posthumans. Such a species could be fundamentally different from any previous life form on Earth, e.g. by merging humans with technological systems. Such scenarios assess the risk that the "old" human species will be outcompeted and driven to extinction by the new, posthuman entity.
Experimental accident
Nick Bostrom suggested that in the pursuit of knowledge, humanity might inadvertently create a device that could destroy Earth and the Solar System. Investigations in nuclear and high-energy physics could create unusual conditions with catastrophic consequences. All of these worries have so far proven unfounded.
For example, scientists worried that the first nuclear test might ignite the atmosphere. Early in the development of thermonuclear weapons there were some concerns that a fusion reaction could "ignite" the atmosphere in a chain reaction that would engulf Earth. Calculations showed the energy would dissipate far too quickly to sustain a reaction.
Others worried that the RHIC or the Large Hadron Collider might start a chain-reaction global disaster involving black holes, strangelets, or false vacuum states. It has been pointed out that much more energetic collisions take place currently in Earth's atmosphere.
Though these particular concerns have been challenged, the general concern about new experiments remains.
Mineral resource exhaustion
Romanian American economist Nicholas Georgescu-Roegen, a progenitor in economics and the paradigm founder of ecological economics, has argued that the carrying capacity of Earth—that is, Earth's capacity to sustain human populations and consumption levels—is bound to decrease sometime in the future as Earth's finite stock of mineral resources is presently being extracted and put to use; and consequently, that the world economy as a whole is heading towards an inevitable future collapse, leading to the demise of human civilization itself. Ecological economist and steady-state theorist Herman Daly, a student of Georgescu-Roegen, has propounded the same argument by asserting that "all we can do is to avoid wasting the limited capacity of creation to support present and future life [on Earth]."
Ever since Georgescu-Roegen and Daly published these views, various scholars in the field have been discussing the existential impossibility of allocating Earth's finite stock of mineral resources evenly among an unknown number of present and future generations. This number of generations is likely to remain unknown to us, as there is no way—or only little way—of knowing in advance if or when mankind will ultimately face extinction. In effect, any conceivable intertemporal allocation of the stock will inevitably end up with universal economic decline at some future point.
Nanotechnology
Many nanoscale technologies are in development or currently in use. The only one that appears to pose a significant global catastrophic risk is molecular manufacturing, a technique that would make it possible to build complex structures at atomic precision. Molecular manufacturing requires significant advances in nanotechnology, but once achieved could produce highly advanced products at low costs and in large quantities in nanofactories of desktop proportions. When nanofactories gain the ability to produce other nanofactories, production may only be limited by relatively abundant factors such as input materials, energy and software.
Molecular manufacturing could be used to cheaply produce, among many other products, highly advanced, durable weapons. Being equipped with compact computers and motors these could be increasingly autonomous and have a large range of capabilities.
Chris Phoenix and Treder classify catastrophic risks posed by nanotechnology into three categories:
From augmenting the development of other technologies such as AI and biotechnology.
By enabling mass-production of potentially dangerous products that cause risk dynamics (such as arms races) depending on how they are used.
From uncontrolled self-perpetuating processes with destructive effects.
Several researchers say the bulk of risk from nanotechnology comes from the potential to lead to war, arms races, and destructive global government. Several reasons have been suggested why the availability of nanotech weaponry may with significant likelihood lead to unstable arms races (compared to e.g. nuclear arms races):
A large number of players may be tempted to enter the race since the threshold for doing so is low;
The ability to make weapons with molecular manufacturing will be cheap and easy to hide;
Therefore, lack of insight into the other parties' capabilities can tempt players to arm out of caution or to launch preemptive strikes;
Molecular manufacturing may reduce dependency on international trade, a potential peace-promoting factor;
Wars of aggression may pose a smaller economic threat to the aggressor since manufacturing is cheap and humans may not be needed on the battlefield.
Since self-regulation by all state and non-state actors seems hard to achieve, measures to mitigate war-related risks have mainly been proposed in the area of international cooperation. International infrastructure may be expanded giving more sovereignty to the international level. This could help coordinate efforts for arms control. International institutions dedicated specifically to nanotechnology (perhaps analogously to the International Atomic Energy Agency IAEA) or general arms control may also be designed. One may also jointly make differential technological progress on defensive technologies, a policy that players should usually favour. The Center for Responsible Nanotechnology also suggests some technical restrictions. Improved transparency regarding technological capabilities may be another important facilitator for arms-control.
Gray goo is another catastrophic scenario, which was proposed by Eric Drexler in his 1986 book Engines of Creation and has been a theme in mainstream media and fiction. This scenario involves tiny self-replicating robots that consume the entire biosphere (ecophagy) using it as a source of energy and building blocks. Nowadays, however, nanotech experts—including Drexler—discredit the scenario. According to Phoenix, a "so-called grey goo could only be the product of a deliberate and difficult engineering process, not an accident".
Nuclear war
Some fear a hypothetical World War III could cause the annihilation of humankind. Nuclear war could yield unprecedented human death tolls and habitat destruction. Detonating large numbers of nuclear weapons would have an immediate, short term and long-term effects on the climate, potentially causing cold weather known as a "nuclear winter" with reduced sunlight and photosynthesis that may generate significant upheaval in advanced civilizations. However, while popular perception sometimes takes nuclear war as "the end of the world", experts assign low probability to human extinction from nuclear war. In 1982, Brian Martin estimated that a US–Soviet nuclear exchange might kill 400–450 million directly, mostly in the United States, Europe and Russia, and maybe several hundred million more through follow-up consequences in those same areas. In 2008, a survey by the Future of Humanity Institute estimated a 4% probability of extinction from warfare by 2100, with a 1% chance of extinction from nuclear warfare.
The scenarios that have been explored most frequently are nuclear warfare and doomsday devices. Mistakenly launching a nuclear attack in response to a false alarm is one possible scenario; this nearly happened during the 1983 Soviet nuclear false alarm incident. Although the probability of a nuclear war per year is slim, Professor Martin Hellman has described it as inevitable in the long run; unless the probability approaches zero, inevitably there will come a day when civilization's luck runs out. During the Cuban Missile Crisis, U.S. president John F. Kennedy estimated the odds of nuclear war at "somewhere between one out of three and even". The United States and Russia have a combined arsenal of 14,700 nuclear weapons, and there is an estimated total of 15,700 nuclear weapons in existence worldwide.
World population and agricultural crisis
The Global Footprint Network estimates that current activity uses resources twice as fast as they can be naturally replenished, and that growing human population and increased consumption pose the risk of resource depletion and a concomitant population crash. Evidence suggests birth rates may be rising in the 21st century in the developed world. Projections vary; researcher Hans Rosling has projected population growth to start to plateau around 11 billion, and then to slowly grow or possibly even shrink thereafter. A 2014 study published in Science asserts that the human population will grow to around 11 billion by 2100 and that growth will continue into the next century.
The 20th century saw a rapid increase in human population due to medical developments and massive increases in agricultural productivity such as the Green Revolution. Between 1950 and 1984, as the Green Revolution transformed agriculture around the globe, world grain production increased by 250%. The Green Revolution in agriculture helped food production to keep pace with worldwide population growth or actually enabled population growth. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (natural gas), pesticides (oil), and hydrocarbon-fueled irrigation. David Pimentel, professor of ecology and agriculture at Cornell University, and Mario Giampietro, senior researcher at the National Research Institute on Food and Nutrition (INRAN), place in their 1994 study Food, Land, Population and the U.S. Economy the maximum U.S. population for a sustainable economy at 200 million. To achieve a sustainable economy and avert disaster, the United States must reduce its population by at least one-third, and world population will have to be reduced by two-thirds, says the study.
The authors of this study believe the mentioned agricultural crisis will begin to have an effect on the world after 2020 and will become critical after 2050. Geologist Dale Allen Pfeiffer claims that coming decades could see spiraling food prices without relief and massive starvation on a global level such as never experienced before.
Since supplies of petroleum and natural gas are essential to modern agriculture techniques, a fall in global oil supplies (see peak oil for global concerns) could cause spiking food prices and unprecedented famine in the coming decades.
Wheat is humanity's third-most-produced cereal. Extant fungal infections such as Ug99 (a kind of stem rust) can cause 100% crop losses in most modern varieties. Little or no treatment is possible and the infection spreads on the wind. Should the world's large grain-producing areas become infected, the ensuing crisis in wheat availability would lead to price spikes and shortages in other food products.
Human activity has triggered an extinction event often referred to as the sixth "mass extinction", which scientists consider a major threat to the continued existence of human civilization. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services, published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, asserts that roughly one million species of plants and animals face extinction from human impacts such as expanding land use for industrial agriculture and livestock rearing, along with overfishing. A 1997 assessment states that over a third of Earth's land has been modified by humans, that atmospheric carbon dioxide has increased around 30 percent, that humans are the dominant source of nitrogen fixation, that humans control most of the Earth's accessible surface fresh water, and that species extinction rates may be over a hundred times faster than normal. Ecological destruction which impacts food production could produce a human population crash.
Non-anthropogenic
Of all species that have ever lived, 99% have gone extinct. Earth has experienced numerous mass extinction events, in which up to 96% of all species present at the time were eliminated. A notable example is the K-T extinction event, which killed the dinosaurs. The types of threats posed by nature have been argued to be relatively constant, though this has been disputed. A number of other astronomical threats have also been identified.
Asteroid impact
An impact event involving a near-Earth object (NEOs) could result in localized or widespread destruction, including widespread extinction and possibly human extinction.
Several asteroids have collided with Earth in recent geological history. The Chicxulub asteroid, for example, was about ten kilometers (six miles) in diameter and is theorized to have caused the extinction of non-avian dinosaurs at the end of the Cretaceous. No sufficiently large asteroid currently exists in an Earth-crossing orbit; however, a comet of sufficient size to cause human extinction could impact the Earth, though the annual probability may be less than 10−8. Geoscientist Brian Toon estimates that while a few people, such as "some fishermen in Costa Rica", could plausibly survive a ten-kilometer (six-mile) meteorite, a hundred-kilometer (sixty-mile) meteorite would be large enough to "incinerate everybody". Asteroids with around a 1 km diameter have impacted the Earth on average once every 500,000 years; these are probably too small to pose an extinction risk, but might kill billions of people. Larger asteroids are less common. Small near-Earth asteroids are regularly observed and can impact anywhere on the Earth injuring local populations. As of 2013, Spaceguard estimates it has identified 95% of all NEOs over 1 km in size. None of the large "dinosaur-killer" asteroids known to Spaceguard pose a near-term threat of collision with Earth.
In April 2018, the B612 Foundation reported "It's a 100 per cent certain we'll be hit [by a devastating asteroid], but we're not 100 per cent sure when." Also in 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, and has developed and released the "National Near-Earth Object Preparedness Strategy Action Plan" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched.
Planetary or interstellar collision
In April 2008, it was announced that two simulations of long-term planetary movement, one at the Paris Observatory and the other at the University of California, Santa Cruz, indicate a 1% chance that Mercury's orbit could be made unstable by Jupiter's gravitational pull sometime during the lifespan of the Sun. Were this to happen, the simulations suggest a collision with Earth could be one of four possible outcomes (the others being Mercury colliding with the Sun, colliding with Venus, or being ejected from the Solar System altogether).
Collision with or a near miss by a large object from outside the Solar System could also be catastrophic to life on Earth. Interstellar objects, including asteroids, comets, and rogue planets, are difficult to detect with current technology until they enter the Solar System, and could potentially do so at high speed.
If Mercury or a rogue planet of similar size were to collide with Earth, all life on Earth could be obliterated entirely: an asteroid 15 km wide is believed to have caused the extinction of the non-avian dinosaurs, whereas Mercury is 4,879 km in diameter. The destabilization of Mercury's orbit is unlikely in the foreseeable future.
A close pass by a large object could cause massive tidal forces that triggered anything from minor earthquakes to liquification of the Earth's crust to Earth being torn apart, becoming a disrupted planet.
Stars and black holes are easier to detect from a longer distance, but are much more difficult to deflect. Passage through the solar system could result in the destruction of the Earth or the Sun by being directly consumed. Astronomers expect the collision of the Milky Way Galaxy with the Andromeda Galaxy in about four billion years, but due to the large amount of empty space between them, most stars are not expected to collide directly.
The passage of another star system into or close to the outer reaches of the Solar System could trigger a swarm of asteroid impacts as the orbit of objects in the Oort Cloud is disturbed, or objects orbiting the two stars collide. It also increases the risk of catastrophic irradiation of the Earth. Astronomers have identified fourteen stars with a 90% chance of coming within 3.26 light years of the Sun in the next few million years, and four within 1.6 light years, including HIP 85605 and Gliese 710. Observational data on nearby stars was too incomplete for a full catalog of near misses, but more data is being collected by the Gaia spacecraft.
Physics hazards
Strangelets, if they exist, might naturally be produced by strange stars, and in the case of a collision, might escape and hit the Earth. Likewise, a false vacuum collapse could be triggered elsewhere in the universe.
Gamma-ray burst
Another interstellar threat is a gamma-ray burst, typically produced by a supernova when a star collapses inward on itself and then "bounces" outward in a massive explosion. Under certain circumstances, these events are thought to produce massive bursts of gamma radiation emanating outward from the axis of rotation of the star. If such an event were to occur oriented towards the Earth, the massive amounts of gamma radiation could significantly affect the Earth's atmosphere and pose an existential threat to all life. Such a gamma-ray burst may have been the cause of the Ordovician–Silurian extinction events. This scenario is unlikely in the foreseeable future. Astroengineering projects proposed to mitigate the risk of gamma-ray bursts include shielding the Earth with ionised smartdust and star lifting of nearby high mass stars likely to explode in a supernova. A gamma-ray burst would be able to vaporize anything in its beams out to around 200 light-years.
The Sun
A powerful solar flare, solar superstorm or a solar micronova, which is a drastic and unusual decrease or increase in the Sun's power output, could have severe consequences for life on Earth.
The Earth will naturally become uninhabitable due to the Sun's stellar evolution, within about a billion years. In around 1 billion years from now, the Sun's brightness may increase as a result of a shortage of hydrogen, and the heating of its outer layers may cause the Earth's oceans to evaporate, leaving only minor forms of life. Well before this time, the level of carbon dioxide in the atmosphere will be too low to support plant life, destroying the foundation of the food chains. See Future of the Earth.
About 7–8 billion years from now, if and after the Sun has become a red giant, the Earth will probably be engulfed by an expanding Sun and destroyed.
Uninhabitable universe
The ultimate fate of the universe is uncertain, but is likely to eventually become uninhabitable, either suddenly or gradually. If it does not collapse into the Big Crunch, over very long time scales the heat death of the universe may render life impossible. The expansion of spacetime could cause the destruction of all matter in a Big Rip scenario.
If our universe lies within a false vacuum, a bubble of lower-energy vacuum could come to exist by chance or otherwise in our universe, and catalyze the conversion of our universe to a lower energy state in a volume expanding at nearly the speed of light, destroying all that is known without forewarning. Such an occurrence is called vacuum decay, or the "Big Slurp".
Extraterrestrial invasion
Intelligent extraterrestrial life, if it exists, could invade Earth, either to exterminate and supplant human life, enslave it under a colonial system, exploit the planet's resources, or destroy it altogether.
Although the existence of sentient alien life has never been conclusively proven, scientists such as Carl Sagan have posited it to be very likely. Scientists consider such a scenario technically possible, but unlikely.
An article in The New York Times Magazine discussed the possible threats for humanity of intentionally sending messages aimed at extraterrestrial life into the cosmos in the context of the SETI efforts. Several public figures such as Stephen Hawking and Elon Musk have argued against sending such messages, on the grounds that extraterrestrial civilizations with technology are probably far more advanced than, and could therefore pose an existential threat to, humanity.
Invasion by microscopic life is also a possibility. In 1969, the "Extra-Terrestrial Exposure Law" was added to the United States Code of Federal Regulations (Title 14, Section 1211) in response to the possibility of biological contamination resulting from the U.S. Apollo Space Program. It was removed in 1991.
Natural pandemic
A pandemic involving one or more viruses, prions, or antibiotic-resistant bacteria. Epidemic diseases that have killed millions of people include smallpox, bubonic plague, influenza, HIV/AIDS, COVID-19, cocoliztli, typhus, and cholera. Endemic tuberculosis and malaria kill over a million people each year. Sudden introduction of various European viruses decimated indigenous American populations. A deadly pandemic restricted to humans alone would be self-limiting as its mortality would reduce the density of its target population. A pathogen with a broad host range in multiple species, however, could eventually reach even isolated human populations. U.S. officials assess that an engineered pathogen capable of "wiping out all of humanity", if left unchecked, is technically feasible and that the technical obstacles are "trivial". However, they are confident that in practice, countries would be able to "recognize and intervene effectively" to halt the spread of such a microbe and prevent human extinction.
There are numerous historical examples of pandemics that have had a devastating effect on a large number of people. The present, unprecedented scale and speed of human movement make it more difficult than ever to contain an epidemic through local quarantines, and other sources of uncertainty and the evolving nature of the risk mean natural pandemics may pose a realistic threat to human civilization.
There are several classes of argument about the likelihood of pandemics. One stems from history, where the limited size of historical pandemics is evidence that larger pandemics are unlikely. This argument has been disputed on grounds including the changing risk due to changing population and behavioral patterns among humans, the limited historical record, and the existence of an anthropic bias.
Another argument is based on an evolutionary model that predicts that naturally evolving pathogens will ultimately develop an upper limit to their virulence. This is because pathogens with high enough virulence quickly kill their hosts and reduce their chances of spreading the infection to new hosts or carriers. This model has limits, however, because the fitness advantage of limited virulence is primarily a function of a limited number of hosts. Any pathogen with a high virulence, high transmission rate and long incubation time may have already caused a catastrophic pandemic before ultimately virulence is limited through natural selection. Additionally, a pathogen that infects humans as a secondary host and primarily infects another species (a zoonosis) has no constraints on its virulence in people, since the accidental secondary infections do not affect its evolution. Lastly, in models where virulence level and rate of transmission are related, high levels of virulence can evolve. Virulence is instead limited by the existence of complex populations of hosts with different susceptibilities to infection, or by some hosts being geographically isolated. The size of the host population and competition between different strains of pathogens can also alter virulence.
Neither of these arguments is applicable to bioengineered pathogens, and this poses entirely different risks of pandemics. Experts have concluded that "Developments in science and technology could significantly ease the development and use of high consequence biological weapons", and these "highly virulent and highly transmissible [bio-engineered pathogens] represent new potential pandemic threats".
Natural climate change
Climate change refers to a lasting change in the Earth's climate. The climate has ranged from ice ages to warmer periods when palm trees grew in Antarctica. It has been hypothesized that there was also a period called "snowball Earth" when all the oceans were covered in a layer of ice. These global climatic changes occurred slowly, near the end of the last Major Ice Age when the climate became more stable. However, abrupt climate change on the decade time scale has occurred regionally. A natural variation into a new climate regime (colder or hotter) could pose a threat to civilization.
In the history of the Earth, many Ice Ages are known to have occurred. An ice age would have a serious impact on civilization because vast areas of land (mainly in North America, Europe, and Asia) could become uninhabitable. Currently, the world is in an Interglacial period within a much older glacial event. The last glacial expansion ended about 10,000 years ago, and all civilizations evolved later than this. Scientists do not predict that a natural ice age will occur anytime soon. The amount of heat-trapping gases emitted into Earth's oceans and atmosphere will prevent the next ice age, which otherwise would begin in around 50,000 years, and likely more glacial cycles.
On a long time scale, natural shifts such as Milankovitch cycles (hypothesized quaternary climatic oscillations) could create unknown climate variability and change.
Volcanism
A geological event such as massive flood basalt, volcanism, or the eruption of a supervolcano could lead to a so-called volcanic winter, similar to a nuclear winter. Human extinction is a possibility. One such event, the Toba eruption, occurred in Indonesia about 71,500 years ago. According to the Toba catastrophe theory, the event may have reduced human populations to only a few tens of thousands of individuals. Yellowstone Caldera is another such supervolcano, having undergone 142 or more caldera-forming eruptions in the past 17 million years.
A massive volcano eruption would eject extraordinary volumes of volcanic dust, toxic and greenhouse gases into the atmosphere with serious effects on global climate (towards extreme global cooling: volcanic winter if short-term, and ice age if long-term) or global warming (if greenhouse gases were to prevail).
When the supervolcano at Yellowstone last erupted 640,000 years ago, the thinnest layers of the ash ejected from the caldera spread over most of the United States west of the Mississippi River and part of northeastern Mexico. The magma covered much of what is now Yellowstone National Park and extended beyond, covering much of the ground from Yellowstone River in the east to Idaho falls in the west, with some of the flows extending north beyond Mammoth Springs.
According to a recent study, if the Yellowstone caldera erupted again as a supervolcano, an ash layer one to three millimeters thick could be deposited as far away as New York, enough to "reduce traction on roads and runways, short out electrical transformers and cause respiratory problems". There would be centimeters of thickness over much of the U.S. Midwest, enough to disrupt crops and livestock, especially if it happened at a critical time in the growing season. The worst-affected city would likely be Billings, Montana, population 109,000, which the model predicted would be covered with ash estimated as 1.03 to 1.8 meters thick.
The main long-term effect is through global climate change, which reduces the temperature globally by about 5–15 °C for a decade, together with the direct effects of the deposits of ash on their crops. A large supervolcano like Toba would deposit one or two meters thickness of ash over an area of several million square kilometers. (1000 cubic kilometers is equivalent to a one-meter thickness of ash spread over a million square kilometers). If that happened in some densely populated agricultural area, such as India, it could destroy one or two seasons of crops for two billion people.
However, Yellowstone shows no signs of a supereruption at present, and it is not certain that a future supereruption will occur.
Research published in 2011 finds evidence that massive volcanic eruptions caused massive coal combustion, supporting models for the significant generation of greenhouse gases. Researchers have suggested that massive volcanic eruptions through coal beds in Siberia would generate significant greenhouse gases and cause a runaway greenhouse effect. Massive eruptions can also throw enough pyroclastic debris and other material into the atmosphere to partially block out the sun and cause a volcanic winter, as happened on a smaller scale in 1816 following the eruption of Mount Tambora, the so-called Year Without a Summer. Such an eruption might cause the immediate deaths of millions of people several hundred kilometers (or miles) from the eruption, and perhaps billions of death worldwide, due to the failure of the monsoons, resulting in major crop failures causing starvation on a profound scale.
A much more speculative concept is the verneshot: a hypothetical volcanic eruption caused by the buildup of gas deep underneath a craton. Such an event may be forceful enough to launch an extreme amount of material from the crust and mantle into a sub-orbital trajectory.
See also
Great Filter
Notes
References
Works cited
.
Existential risk
Man-made disasters
International responses to disasters
Doomsday scenarios
Apocalyptic fiction | Global catastrophe scenarios | [
"Biology"
] | 8,186 | [] |
69,385,263 | https://en.wikipedia.org/wiki/Arthropodicide | An arthropodicide is a pesticide which acts upon arthropods. The vast majority of arthropodicides used are
Insecticides
however there are other types. The second most common class is
Acaricides/miticides. | Arthropodicide | [
"Biology"
] | 53 | [
"Biocides",
"Arthropodicides"
] |
69,385,764 | https://en.wikipedia.org/wiki/EmojiGrid | The EmojiGrid is an affective self-report tool consisting of a rectangular grid that is labelled with emojis. It is trademark of Kikkoman. The facial expressions of the emoji labels vary from disliking via neutral to liking along the x-axis, and gradually increase in intensity along the y-axis. To report their affective appraisal of a given stimulus, users mark the location inside the grid that best represents their impression. The EmojiGrid can either be used as a paper or computer-based response tool. The images needed to implement the EmojiGrid are freely available from the OSF repository.
Applications
The EmojiGrid was inspired by Russell's Affect Grid and was originally developed and validated for the affective appraisal of food stimuli, since conventional affective self-report tools (e.g., the Self-Assessment Manikin) are frequently misunderstood in that context. It has since been used and validated for the affective appraisal of a wide range of affective stimuli such as images, audio and video clips, 360 VR videos, touch events, food, and odors. It has also been used for the affective analysis of architectural spaces to assess affective experience of trail racing, and to assess the emotional face evaluation capability of people with early dementia. Since it is intuitive and language independent, the EmojiGrid is also suitable for cross-cultural research.
Implementation
In a computer-based response paradigm, only the image area inside the horizontal and vertical grid borders should be responsive (clickable), so that users can report their affective response by pointing and/or clicking inside the grid. In practice, this may be achieved by superimposing (1) a clickable image of the unlabeled grid area on top of (2) a larger image showing the grid area together with the emoji labels. The images needed to implement the EmojiGrid are freely available from the OSF repository. An implementation of the EmojiGrid rating task in the Gorilla experiment builder is freely available from the Gorilla Open Materials platform.
See also
Affect measures
Emotion classification
Self-report inventory
PAD emotional state model
Valence (psychology)
Arousal
Further reading
References
Emotion
Personality tests
Emoji | EmojiGrid | [
"Biology"
] | 467 | [
"Emotion",
"Behavior",
"Human behavior"
] |
69,387,329 | https://en.wikipedia.org/wiki/Future%20Soldier%20%28British%20Army%29 | Future Soldier is a reform of the British Army resulting from the Integrated Review of Security, Defence, Development and Foreign Policy ("Global Britain in a Competitive Age") published in March 2021. The aim of the reform is to create a more lethal, agile and expeditionary force, able to fight and win wars and to operate in the grey-zone between peace and war. Future Soldier was published on 25 November 2021 and deals with the organizational changes of the British Army, with changes to personnel and equipment were set out in the Defence in a Competitive Age paper published on 22 March 2021.
The British Army will be reduced to 73,000 regular personnel by 2025. The reserves will be kept at the current level.
Allied Rapid Reaction Corps
The Allied Rapid Reaction Corps (ARRC) is a high readiness corps-level command tasked to lead NATO’s Response Force (NRF).
Allied Rapid Reaction Corps (ARRC), in Innsworth
1st Signal Brigade
1st Signal Brigade provides communications elements to Allied Rapid Reaction Corps (ARRC), Permanent Joint Headquarters (PJHQ), Joint Helicopter Command (JHC), Joint Task Force HQ (JTFHQ), and other government departments.
1st Signal Brigade, in Innsworth
10 Signal Regiment, Royal Corps of Signals, in Corsham (Communication and Information Support)
16 Signal Regiment, Royal Corps of Signals, in Stafford (Sustainment Signals Support Regiment)
22 Signal Regiment, Royal Corps of Signals, in Stafford (HQ ARRC Signal Regiment)
30 Signal Regiment, Royal Corps of Signals, in Bramcote (JHC/JTFHQ Signals Regiment)
32 Signal Regiment, Royal Corps of Signals, in Glasgow (Signal Regiment - Reserve)
39 Signal Regiment, Royal Corps of Signals, in Bristol (Signal Regiment - Reserve)
Gurkha ARRC Support Battalion, in Innsworth (Logistics and Force Protection for HQ ARRC)
299 Signal Squadron, Royal Corps of Signals, in Bletchley (Special Communications)
104 Theatre Sustainment Brigade
104 Theatre Sustainment Brigade is a theatre logistic enabling formation that operates strategic and operational Lines of Communications.
104 Theatre Sustainment Brigade, in South Cerney
9 Supply Regiment, Royal Logistic Corps, in Hullavington (Theatre Support Regiment)
17 Port and Maritime Regiment, Royal Logistic Corps, in Marchwood (Port and Maritime Regiment)
29 Postal Courier and Movement Regiment, Royal Logistic Corps, in South Cerney (Movement Control Regiment)
9 Theatre Support Battalion, Royal Electrical and Mechanical Engineers, in Aldershot (Equipment Support; unit to be established by 2025)
2 Operational Support Group, Royal Logistic Corps, in Grantham (Logistics Operational Support Group; moves to Cottesmore in 2025)
152 Logistic Regiment, Royal Logistic Corps, in Belfast (Fuel Support Regiment - Reserve)
162 Logistic Regiment, Royal Logistic Corps, in Nottingham (Movement Control and Communications Regiment - Reserve)
165 Port and Maritime Regiment, Royal Logistic Corps, in Plymouth (Port and Maritime Regiment - Reserve)
167 Regiment, Royal Logistic Corps, in Grantham (Catering Support Regiment - Reserve; moves to Cottesmore by 2027)
Field Army
Field Army, in Andover
1st (UK) Division, in York
3rd (UK) Division, in Bulford
6th (UK) Division, in Upavon
Field Army Troops, in Andover
1st (UK) Division
1st (UK) Division is the British Army's main contributor for land operations outside the Euro-Atlantic area and operations on NATO's flanks.
1st (UK) Division, in York (Moves to Catterick by 2028)
4th Light Brigade Combat Team
4th Light Brigade Combat Team consists of Light Infantry formations.
4th Light Brigade Combat Team, in Catterick
Light Dragoons, in Catterick (Light Cavalry)
1st Battalion, Coldstream Guards, in Windsor (Light Infantry)
1st Battalion, Grenadier Guards, in Aldershot (Light Infantry)
1st Battalion, Duke of Lancaster's Regiment, in Cyprus (Light Infantry; moves to Blackpool in 2024)
2nd Battalion, Royal Gurkha Rifles, in Folkestone (Light Infantry)
2nd Battalion, Royal Regiment of Scotland, in Edinburgh (Light Infantry)
2nd Battalion, The Rifles, in Lisburn (Light Infantry)
103 Regiment, Royal Artillery, in St Helens (Close Support Light Artillery - Reserve)
75 Engineer Regiment, Royal Engineers, in Warrington (Close Support Engineers - Reserve)
154 (Scottish) Logistic Regiment, Royal Logistic Corps, in Dunfermline (Transport Regiment - Reserve)
102 Battalion, Royal Electrical and Mechanical Engineers, in Newton Aycliffe (Close Support - Reserve)
7th Light Mechanised Brigade Combat Team
7th Light Mechanised Brigade Combat Team is a high readiness and highly mobile formation.
7th Light Mechanised Brigade Combat Team, in Cottesmore
Royal Scots Dragoon Guards, in Leuchars (Light Cavalry)
1st Battalion, Scots Guards, in Catterick (Light Mechanised Infantry)
1st Battalion, Royal Yorkshire Regiment, in Catterick (Light Mechanised Infantry)
1st Battalion, The Rifles, in Cyprus (Light Mechanised Infantry; moves to Chepstow in 2025)
2nd Battalion, Royal Anglian Regiment, in Cottesmore (Light Mechanised Infantry)
4th Battalion, Royal Regiment of Scotland, in Catterick (Light Mechanised Infantry)
4th Regiment, Royal Artillery, in Topcliffe (Close Support Light Artillery)
105 Regiment, Royal Artillery, in Edinburgh (Close Support Light Artillery - Reserve)
32 Engineer Regiment, Royal Engineers, in Catterick (Close Support Engineers)
6 Regiment, Royal Logistic Corps, in Dishforth (Close Support Logistics)
3 Medical Regiment, Royal Army Medical Corps, in Catterick (Close Support Medical Regiment)
1 Battalion, Royal Electrical and Mechanical Engineers, in Catterick (Close Support)
16 Air Assault Brigade Combat Team
16 Air Assault Brigade Combat Team, in Colchester
2nd Battalion, Parachute Regiment, in Colchester (Airborne Infantry)
3rd Battalion, Parachute Regiment, in Colchester (Airborne Infantry)
4th Battalion, Parachute Regiment, in Leeds (Airborne Infantry - Reserve)
1st Battalion, Royal Irish Regiment, in Ternhill (Light Recce Strike Infantry; will move to Edinburgh by 2027)
1st Battalion, Royal Gurkha Rifles, in Brunei (Air Assault Infantry)
7th Parachute Regiment, Royal Horse Artillery, in Colchester (Airborne Close Support Artillery)
23 Parachute Engineer Regiment, Royal Engineers, in Woodbridge (Close Support Air Manoeuvre Engineers)
13 Air Assault Regiment, Royal Logistic Corps, in Colchester (Air Assault Logistics)
16 Medical Regiment, Royal Army Medical Corps, in Colchester (Air Manoeuvre Medical Regiment)
216 Signal Squadron, Royal Corps of Signals, in Colchester (Communication and Information Support)
Pathfinders, in Colchester
11th Security Force Assistance Brigade
11th Security Force Assistance Brigade trains and mentors allied and partner nations' ground units.
11th Security Force Assistance Brigade, in Aldershot
1st Battalion, Irish Guards, in Aldershot (Security Force Assistance)
1st Battalion, Royal Anglian Regiment, in Cottesmore (Security Force Assistance)
3rd Battalion, The Rifles, in Edinburgh (Security Force Assistance; moves to Blackpool by 2027)
3rd Battalion (Black Watch), Royal Regiment of Scotland, in Inverness (Security Force Assistance)
4th Battalion, Princess of Wales's Royal Regiment, in Redhill (Light Infantry - Reserve)
Outreach Group, in Hermitage (Outreach and Cultural Support; moves to Pirbright in 2027)
19th Brigade
19th Brigade, in York (Reactivated in 2022)
Scottish and North Irish Yeomanry, in Edinburgh (Light Cavalry - Reserve)
Queen's Own Yeomanry, in Newcastle upon Tyne (Light Cavalry - Reserve)
2nd Battalion, Royal Irish Regiment, in Lisburn (Infantry - Reserve)
3rd Battalion, Royal Anglian Regiment, in Bury St Edmunds (Infantry - Reserve)
4th Battalion, Royal Yorkshire Regiment, in York (Infantry - Reserve)
4th Battalion, Duke of Lancaster's Regiment, in Preston (Infantry - Reserve)
6th Battalion, The Rifles, in Exeter (Infantry - Reserve)
6th Battalion, Royal Regiment of Scotland, in Glasgow (Infantry - Reserve)
7th Battalion, Royal Regiment of Scotland, in Perth (Infantry - Reserve)
8th Battalion, The Rifles, in Bishop Auckland (Infantry - Reserve)
8 Engineer Brigade
8 Engineer Brigade commands the army's two engineer specialist groups: 12 Group provides land and air force support engineering. 29 Group provides Explosive Ordnance Disposal, and Counter-Chemical Biological Radiological and Nuclear capabilities.
8 Engineer Brigade, in Minley
12 Force Support Group, at RAF Wittering
36 Regiment, Royal Engineers, in Maidstone (Force Support Engineers; moves to Cottesmore by 2028)
39 Regiment, Royal Engineers, in Kinloss Barracks (Force Support (Air) Engineers)
71 Regiment, Royal Engineers, in Leuchars (Force Support Engineers - Reserve)
20 Works Group, Royal Engineers, at RAF Wittering (Specialist Air Infrastructure Support)
62 Works Group, Royal Engineers, in Chilwell (Infrastructure Support; moves to Stafford in 2026)
63 Works Group, Royal Engineers, in Chilwell (Infrastructure Support; moves to Stafford in 2026)
65 Works Group, Royal Engineers, in Chilwell (Infrastructure Support - Reserve; moves to Stafford in 2026)
66 Works Group, Royal Engineers, in Chilwell (Infrastructure Support; moves to Stafford in 2026)
29 EOD & Search Group, in Aldershot
11 EOD Regiment, Royal Logistic Corps, in Didcot (EOD and Search Regiment)
28 Regiment, Royal Engineers, in Woodbridge (Counter CBRN)
33 Regiment, Royal Engineers, in Wimbish (EOD and Search Regiment)
35 Regiment, Royal Engineers, in Wimbish (EOD and Search Regiment)
101 (City of London) Regiment, Royal Engineers, in Catford (EOD and Search Regiment - Reserve)
1st Military Working Dog Regiment, in Cottesmore (Military working dogs)
102 Operational Sustainment Brigade
102 Operational Sustainment Brigade moves troops and equipment to the battle area and logistically sustains fighting formations.
102 Operational Sustainment Brigade, in Grantham (Will move to York in 2024)
7 Regiment, Royal Logistic Corps, in Abingdon (Force Logistic Regiment)
150 Regiment, Royal Logistic Corps, in Kingston upon Hull (Transport Regiment - Reserve)
158 Regiment, Royal Logistic Corps, in Peterborough (Aviation Support Regiment - Reserve)
159 Regiment, Royal Logistic Corps, in Coventry (Supply & Transport Regiment - Reserve)
2 Battalion, Royal Electrical and Mechanical Engineers, in Leuchars (Force Support)
101 Battalion, Royal Electrical and Mechanical Engineers, in Keynsham (Force Support - Reserve)
1st Divisional Integrated Effects Group
1st Divisional Integrated Effects Group, in Catterick
1 Military Intelligence Battalion, Intelligence Corps, in Catterick (Military Intelligence)
5 Military Intelligence Battalion, Intelligence Corps, in Edinburgh (Military Intelligence - Reserve)
2 Signal Regiment, Royal Corps of Signals, in York (Communication and Information Support; will move to Catterick by 2028)
37 Signal Regiment, Royal Corps of Signals, in Redditch (Signal Regiment - Reserve)
3rd (UK) Division
3rd (UK) Division, in Bulford
12th Armoured Brigade Combat Team
12th Armoured Brigade Combat Team, in Bulford
King's Royal Hussars, in Tidworth (Armoured Cavalry)
Royal Tank Regiment, in Tidworth (Armoured)
Royal Wessex Yeomanry, in Bovington (Armoured - Reserve)
1st Battalion, Mercian Regiment, in Bulford (Mechanised Infantry)
4th Battalion, Mercian Regiment, in Wolverhampton (Infantry - Reserve)
1st Battalion, Royal Welsh, in Tidworth (Mechanised Infantry)
3rd Battalion, Royal Welsh, in Cardiff (Infantry - Reserve)
4 Regiment, Royal Logistic Corps, in Abingdon (Close Support Logistics; will move to Catterick in 2028)
4 Battalion, Royal Electrical and Mechanical Engineers, in Tidworth (Armoured Close Support)
2 Medical Regiment, Royal Army Medical Corps, in Tidworth (Close Support Medical Regiment)
20th Armoured Brigade Combat Team
20th Armoured Brigade Combat Team, in Bulford
Royal Dragoon Guards, in Warminster (Armoured Cavalry)
Queen's Royal Hussars, in Tidworth (Armoured)
1st Battalion, Princess of Wales's Royal Regiment, in Woolwich to Cyprus, then Bulford / Tidworth (Mechanised Infantry)
3rd Battalion, Princess of Wales's Royal Regiment, in Canterbury (Infantry - Reserve)
1st Battalion, Royal Regiment of Fusiliers, in Tidworth (Mechanised Infantry)
5th Battalion, Royal Regiment of Fusiliers, in Alnwick (Infantry - Reserve)
5th Battalion, The Rifles, in Bulford (Mechanised Infantry)
7th Battalion, The Rifles, in Kensington (Infantry - Reserve)
1 Regiment, Royal Logistic Corps, in Bicester (Close Support Logistics)
3 Battalion, Royal Electrical and Mechanical Engineers, in Tidworth (Armoured Close Support)
1 Medical Regiment, Royal Army Medical Corps, in Tidworth (Close Support Medical Regiment)
1st Deep Recce Strike Brigade Combat Team
1st Deep Recce Strike Brigade Combat Team, in Tidworth
Household Cavalry Regiment, in Bulford (Armoured Cavalry)
Royal Lancers, in Catterick (Armoured Cavalry; will move to Tidworth in 2026)
1st Queen's Dragoon Guards, in Swanton Morley (Light Cavalry; will move to Caerwent by 2027)
Royal Yeomanry, in Leicester (Light Cavalry - Reserve)
1st Regiment, Royal Horse Artillery, in Larkhill (Armoured Close Support Artillery)
3rd Regiment, Royal Horse Artillery, in Newcastle upon Tyne (Deep Fires)
5th Regiment, Royal Artillery, in Catterick (Surveillance and Target Acquisition)
19 Regiment, Royal Artillery, in Larkhill (Armoured Close Support Artillery)
26 Regiment, Royal Artillery, in Larkhill (Deep Fires)
101 Regiment, Royal Artillery, in Gateshead (Deep Fires - Reserve)
104 Regiment, Royal Artillery, in Newport (Close Support Artillery - Reserve)
6 Armoured Close Support Battalion, Royal Electrical and Mechanical Engineers, in Tidworth (Close Support)
7 Air Defence Group
7 Air Defence Group, in Thorney Island
12 Regiment, Royal Artillery, in Thorney Island (Short Range Air Defence)
16 Regiment, Royal Artillery, in Thorney Island (Medium Range Air Defence)
106 Regiment, Royal Artillery, in London (Air Defence - Reserve)
25 (Close Support) Engineer Group
25 (Close Support) Engineer Group, in Bulford
21 Engineer Regiment, Royal Engineers, in Ripon (Force Support Engineers; will move to Catterick in 2025)
22 Engineer Regiment, Royal Engineers, in Perham Down (Close Support Engineers)
26 Engineer Regiment, Royal Engineers, in Perham Down (Close Support Engineers)
Royal Monmouthshire Royal Engineers, in Monmouth (Engineers - Reserve)
101 Operational Sustainment Brigade
101 Operational Sustainment Brigade, in Aldershot
10 Queen's Own Gurkha Logistic Regiment, in Aldershot (Divisional Support Logistics)
27 Regiment, Royal Logistic Corps, in Aldershot (Divisional Support Logistics)
151 Regiment, Royal Logistic Corps, in Croydon (Transport Regiment - Reserve)
156 Regiment, Royal Logistic Corps, in Liverpool (Supply Regiment - Reserve)
157 (Welsh) Regiment, Royal Logistic Corps, in Cardiff (Transport Regiment - Reserve)
5 Battalion, Royal Electrical and Mechanical Engineers, in Lyneham (Force Support)
103 Battalion, Royal Electrical and Mechanical Engineers, in Northampton (Force Support - Reserve)
7 Signals Group
7 Signals Group, in Bulford
1 Signal Regiment, Royal Corps of Signals, in Perham Down (Communication and Information Support)
3 Signal Regiment, Royal Corps of Signals, in Bulford (Communication and Information Support)
15 Signal Regiment, Royal Corps of Signals, in Perham Down (Communication and Information Support)
71 Signal Regiment, Royal Corps of Signals, in Bexley Heath (Signal Regiment - Reserve)
3rd UK Divisional Integrated Effects Group
3rd UK Divisional Integrated Effects Group, in Bulford
4 Military Intelligence Battalion, Intelligence Corps, in Bulford (Military Intelligence)
7 Military Intelligence Battalion, Intelligence Corps, in Bristol (Military Intelligence - Reserve)
6th (UK) Division
6th (UK) Division, in Upavon
Army Special Operations Brigade
Army Special Operations Brigade, in Aldershot
1st Battalion, Ranger Regiment, in Belfast (Army Rangers; former 1st Battalion, Royal Regiment of Scotland)
2nd Battalion, Ranger Regiment, in Aldershot (Army Rangers; former 2nd Battalion, Princess of Wales's Royal Regiment)
3rd Battalion, Ranger Regiment, in Pirbright (Army Rangers; former 2nd Battalion, Duke of Lancaster's Regiment; will move to Aldershot in 2027)
4th Battalion, Ranger Regiment, in Aldershot (Army Rangers; former 4th Battalion, The Rifles)
255 Signal Squadron, Royal Corps of Signals, in Perham Down (Communication and Information Support; will move to Aldershot in 2027)
77th Brigade
77th Brigade, in Hermitage (Will move to Pirbright in 2026)
Staff Corps, in Hermitage (Capacity Building; will move to Pirbright in 2026)
Deployed Information Activities, in Hermitage (Deployed Information Activity; will move to Pirbright in 2026)
Stand-off Information Activities, in Hermitage (Stand-off Information Activity; will move to Pirbright in 2026)
6 Military Intelligence Battalion, Intelligence Corps, in Manchester (Military Intelligence, hybrid active/reserve unit; will move to Pirbright by 2026)
The Honourable Artillery Company, in London (Surveillance and Target Acquisition - Reserve)
Field Army Troops
Field Army Troops, in Andover
Intelligence, Surveillance and Reconnaissance Group
Intelligence, Surveillance and Reconnaissance Group, in Upavon
32 Regiment, Royal Artillery, in Larkhill (Miniature Un-crewed Aerial Systems: Puma and Wasp AE)
47 Regiment, Royal Artillery, in Larkhill (Tactical Un-crewed Aerial Systems: Watchkeeper WK450)
2 Military Intelligence Battalion, Intelligence Corps, in Upavon (Intelligence Exploitation, hybrid active/reserve unit)
3 Military Intelligence Battalion, Intelligence Corps, in London (Military Intelligence - Reserve)
Specialist Group Military Intelligence, in Hermitage (Military Intelligence - Reserve; will move to Aldershot by 2026)
Land Intelligence Fusion Centre, in Hermitage (Will move to Andover in 2027)
2nd Medical Group
2nd Medical Group, in Strensall
21 Multi-Role Medical Regiment, in Strensall (Restructured 34 Field Hospital)
22 Multi-Role Medical Regiment, in Preston (Restructured 22 Field Hospital; will move to Strensall by 2026)
202 (Midlands) Multi-Role Medical Regiment, in Birmingham (Reserve; restructured 202 Field Hospital)
203 (Welsh) Multi-Role Medical Regiment, in Cardiff (Reserve; restructured 203 Field Hospital)
206 (North-West) Multi-Role Medical Regiment, in Manchester and Liverpool (Reserve; merged and restructured 207 and 208 field hospitals)
210 (North Irish) Multi-Role Medical Regiment, in Belfast (Reserve; merged and restructured 204 Field Hospital and 253 Medical Regiment)
214 (North-East) Multi-Role Medical Regiment, in Newcastle upon Tyne and Sheffield (Reserve; merged and restructured 201 and 212 field hospitals)
215 (Scottish) Multi-Role Medical Regiment, in Glasgow (Reserve; merged and restructured 205 Field Hospital and 225 Medical Regiment)
243 (Wessex) Multi-Role Medical Regiment, in Keynsham (Reserve; restructured 243 Field Hospital)
254 (East of England) Multi-Role Medical Regiment, in Cambridge (Reserve; restructured 254 Medical Regiment)
256 (London and South-East) Multi-Role Medical Regiment, in Walworth (Reserve; restructured 256 Field Hospital)
306 Hospital Support Regiment, in Strensall (Hospital Support Regiment - Reserve)
335 Medical Evacuation Regiment, in Strensall (Medical Evacuation - Reserve)
Medical Operations Support Unit, in Strensall (Medical Operations Support Unit - Reserve)
Cyber and Electro Magnetic Activities Effects Group
Cyber and Electro Magnetic Activities Effects Group, in Andover
13 Signal Regiment, Royal Corps of Signals, in Blandford (Cyber; will move to Corsham by 2028)
14 Signal Regiment, Royal Corps of Signals, in Brawdy (Electronic Warfare; will move to Innsworth by 2028)
21 Signal Regiment, Royal Corps of Signals, in Colerne (Electronic Warfare; will move to Innsworth by 2028)
Land Warfare Centre
Land Warfare Centre, in Warminster
Collective Training Group
British Army Training Unit Suffield (BATUS), in Suffield (Canada)
British Army Training Unit Kenya (BATUK), in Nanyuki (Kenya)
British Army Training and Support Unit Belize (BATSUB), in Ladyville (Belize)
Command, Staff and Tactical Training Group (CSTTG)
Mission Ready Training Centre (MRTC), in Royston
Combat Ready Training Centre
Army Schools
1 Royal School of Military Engineering Regiment, in Chatham
2 Training Regiment, Army Air Corps, at AAC Middle Wallop
3 Royal School of Military Engineering Regiment, in Minley Manor
14 Regiment, Royal Artillery, in Larkhill
25 Training Regiment, Royal Logistic Corps, in Leconfield
Experimentation and Trials Group
Infantry Trials and Development Unit (ITDU)
Armoured Trials and Development Unit (ATDU)
Royal Artillery Trials and Development Unit (RA TDU)
Royal Engineers Trials and Development Unit (RE TDU)
Combat Service Support Training and Development Unit (CSS TDU)
2nd Battalion, Royal Yorkshire Regiment, in Catterick
Home Command
Home Command, in Aldershot
Army Personnel Centre (APC), in Glasgow
Army Personnel Services Group (APSG)
Arms and Services
Army Recruiting and Initial Training Command
Army Recruiting and Initial Training Command (ARITC), in Upavon
Army Officer Selection Board (AOSB), in Westbury (Officer Selection)
Recruiting Group (RG), in Upavon (Recruit enlistment)
School of Infantry (SCHINF), in Catterick (Infantry training)
Initial Training Group (ITG), in Pirbright and Grantham (Phase One training)
Army Adventurous Training Group (Army) (ATG(A), in Upavon (Adventurous training)
Royal Military Academy Sandhurst Group
Royal Military Academy Sandhurst Group, in Sandhurst
Royal Military Academy Sandhurst (RMAS)
University Officer Training Corps (UOTC)
General Staff Centre (GSC)
Centre for Army Leadership (CAL)
London District
London District (LONDIST), in Westminster
Household Cavalry Mounted Regiment, at Hyde Park Barracks in Knightsbridge (Public Duties and State Ceremonial)
King's Troop, Royal Horse Artillery, at Royal Artillery Barracks in Woolwich (Public Duties and State Ceremonial)
1st Battalion, Welsh Guards, in Windsor (Light Infantry)
1st Battalion, London Guards, in Battersea (Infantry - Reserve)
Public Duties Teams, at Wellington Barracks in London (Public Duties and State Ceremonial)
Nijmegen Company, Grenadier Guards
No. 7 Company, Coldstream Guards
F Company, Scots Guards
No. 9 Company, Irish Guards (Until 2027)
No. 12 Company, Irish Guards (Until 2027)
Household Division Bands
Mounted Band of the Household Cavalry
Band of the Grenadier Guards
Band of the Coldstream Guards
Band of the Scots Guards
Band of the Irish Guards
Band of the Welsh Guards
Countess of Wessex's String Orchestra
Regional Bands
Band of the Royal Regiment of Scotland
Band and Bugles of The Rifles
Band of the Brigade of Gurkhas
Prince of Wales Band
Catterick Band
Tidworth Band
Sandhurst Band
Regional Command
Regional Command (RC), in Aldershot
Regional Point of Command (RPoC) South East, in Aldershot
Regional Point of Command South West, in Tidworth
Regional Point of Command North (Its exact location remains subject to further work.)
Regional Point of Command Centre, in Cottesmore
38 (Irish) Brigade, in Lisburn
51st Infantry Brigade and Headquarters Scotland, in Edinburgh
Balaklava Company, 5th Battalion, The Royal Regiment of Scotland, in Edinburgh
160th (Welsh) Brigade, in Brecon
Joint Helicopter Command
Joint Helicopter Command, in Andover
Army Aviation Centre, at AAC Middle Wallop
Watchkeeper Force HQ, at AAC Middle Wallop
1st Aviation Brigade Combat Team
1st Aviation Brigade Combat Team, at AAC Middle Wallop
1 Regiment, Army Air Corps, at RNAS Yeovilton (Aviation Reconnaissance)
3 Regiment, Army Air Corps, at Wattisham Flying Station (Attack Aviation)
4 Regiment, Army Air Corps, at Wattisham Flying Station (Attack Aviation)
5 Regiment, Army Air Corps, at Aldergrove Flying Station (Aviation Reconnaissance)
6 Regiment, Army Air Corps, in Bury St Edmunds (Aviation Support Regiment - Reserve)
7 AS Battalion, Royal Electrical and Mechanical Engineers, at Wattisham Flying Station (Aviation Close Support)
Provost Marshal (Army)
Provost Marshal (Army) polices the army and undertakes activities concerned with investigations, custodial matters and security in the UK. The 1st Royal Military Police Group provides police support to the force at an operational level, which includes operational detention, and support to security and stability policing.
Provost Marshal (Army), in Andover
1st Royal Military Police Group
1st Royal Military Police Group, in Andover
1 Regiment, Royal Military Police, in Catterick (Military Police, hybrid active/reserve unit)
3 Regiment, Royal Military Police, in Bulford (Military Police, hybrid active/reserve unit)
Special Investigation Branch, in Bulford (Special Investigations Branch)
Special Operations Unit, in Southwick Park (Specialist Operations)
Military Provost Staff Corps, in Colchester (Military Police)
Army units in other parts of Defence
Army units assigned to other parts of Defence:
Navy Command
3 Commando Brigade, in Plymouth
29 Commando Regiment, Royal Artillery, in Plymouth (Commando Artillery)
24 Commando Regiment, Royal Engineers, in Chivenor (Commando Engineers)
Air Command
No. 22 Group, at RAF High Wycombe
11 Signal Regiment, Royal Corps of Signals, in Blandford (Defence School of Communications and Information Systems)
8 Training Battalion, Royal Electrical and Mechanical Engineers, in Lyneham (REME Training Battalion)
UK Strategic Command
Defence Intelligence, in London
42 Engineer Regiment (Geographic), Royal Engineers, at RAF Wyton (Geographical Support)
Director Overseas Basing, in London
Royal Gibraltar Regiment, in Gibraltar (Light Infantry)
Graphic overview
Unit changes
The following are the units that will be raised, disbanded, amalgamated, re-designated, and re-roled under the reforms:
Units raised
No 9 Company, Irish Guards
No 12 Company, Irish Guards
Coriano Company, Royal Gurkha Rifles
Falklands Company, Royal Gurkha Rifles
9 Equipment Support Battalion, Royal Electrical and Mechanical Engineers
Disbandment
3 Medical Regiment
3 Regiment, Royal Logistic Corps
Amalgamations
Infantry
1st and 2nd Battalions of the Mercian Regiment, as the 1st Battalion.
Royal Army Medical Corps
207 (Manchester) Field Hospital and 208 (Liverpool) Field Hospital to form 206 (North West) Multi-Role Medical Regiment.
204 (North Irish) Field Hospital and 253 (North Irish) Medical Regiment to form 210 (North Irish) Multi-Role Medical Regiment.
201 (Northern) Field Hospital and 212 (Yorkshire) Field Hospital to form 214 (North East) Multi-Role Medical Regiment.
205 (Scottish) Field Hospital and 225 (Scottish) Medical Regiment to form 215 (Scottish) Multi-Role Medical Regiment.
Re-designations
Infantry
London Regiment to become the London Guards.
Royal Scots Borderers, 1st Battalion, Royal Regiment of Scotland to become 1st Battalion, Ranger Regiment.
2nd Battalion, Princess of Wales's Royal Regiment to become 2nd Battalion, Ranger Regiment.
2nd Battalion, Duke of Lancaster's Regiment to become 3rd Battalion, Ranger Regiment.
4th Battalion, The Rifles to become 4th Battalion, Ranger Regiment.
3rd Battalion, Royal Gurkha Rifles not formed, with personnel instead forming reinforcement companies for Ranger Regiment
Royal Army Medical Corps
22 Field Hospital to become 22 Multi-Role Medical Regiment.
34 Field Hospital to become 21 Multi-Role Medical Regiment.
202 (Midlands) Field Hospital to become 202 (Midlands) Multi-Role Medical Regiment.
203 (Welsh) Field Hospital to become 203 (Welsh) Multi-Role Medical Regiment.
243 (The Wessex) Field Hospital to become 243 (Wessex) Multi-Role Medical Regiment.
254 (East of England) Medical Regiment to become 254 (East of England) Multi-Role Medical Regiment.
256 (City of London) Field Hospital to become 256 (London and South East) Multi-Role Medical Regiment.
Re-role
Infantry
1st Battalion, Irish Guards from Light Role Infantry to Security Force Assistance.
1st Battalion, Royal Anglian Regiment from Light Role Infantry to Security Force Assistance.
3rd Battalion, The Rifles from Light Mechanised Infantry to Security Force Assistance.
Black Watch, 3rd Battalion, Royal Regiment of Scotland from Light Mechanised Infantry to Security Force Assistance.
1st Battalion, Welsh Guards from Light Mechanised Infantry to Light Role Infantry.
1st Battalion, The Rifles from Light Role Infantry to Light Mechanised Infantry.
2nd Battalion, Royal Anglian Regiment from Light Role Infantry to Light Mechanised Infantry.
1st Battalion, Royal Yorkshire Regiment from Armoured Infantry to Light Mechanised Infantry.
The Highlanders, 4th Battalion, Royal Regiment of Scotland from Armoured Infantry to Light Mechanised Infantry.
1st Battalion, Princess of Wales's Royal Regiment from Light Role Infantry to Mechanised Infantry.
Royal Armoured Corps
King's Royal Hussars from Armoured to Armoured Cavalry.
Notes
References
21st-century history of the British Army | Future Soldier (British Army) | [
"Engineering"
] | 6,041 | [
"Military projects",
"Future Soldier"
] |
69,388,599 | https://en.wikipedia.org/wiki/Polyhedral%20map%20projection | A polyhedral map projection is a map projection based on a spherical polyhedron. Typically, the polyhedron is overlaid on the globe, and each face of the polyhedron is transformed to a polygon or other shape in the plane. The best-known polyhedral map projection is Buckminster Fuller's Dymaxion map. When the spherical polyhedron faces are transformed to the faces of an ordinary polyhedron instead of laid flat in a plane, the result is a polyhedral globe.
Often the polyhedron used is a Platonic solid or Archimedean solid. However, other polyhedra can be used: the AuthaGraph projection makes use of a polyhedron with 96 faces, and the myriahedral projection allows for an arbitrary large number of faces.
Although interruptions between faces are common, and more common with an increasing number of faces, some maps avoid them: the Lee conformal projection only has interruptions at its border, and the AuthaGraph projection scales its faces so that the map fills a rectangle without internal interruptions. Some projections can be tesselated to fill the plane, the Lee conformal projection among them.
To a degree, the polyhedron and the projection used to transform each face of the polyhedron can be considered separately, and some projections can be applied to differently shaped faces. The gnomonic projection transforms the edges of spherical polyhedra to straight lines, preserving all polyhedra contained within a hemisphere, so it is a common choice. The Snyder equal-area projection can be applied to any polyhedron with regular faces. The projection used in later versions of the Dymaxion map can be generalized to other equilateral triangular faces, and even to certain quadrilaterals.
Polyhedral map projections are useful for creating discrete global grids, as with the quadrilateralized spherical cube and Icosahedral Snyder Equal Area (ISEA) grids.
History
The earliest known polyhedral projection is the octant projection developed by Leonardo da Vinci or his associate around 1514, which transforms the faces of an octahedron to Reuleaux triangles.
Christian Gottlieb Reichard created a polyhedral globe based on the cube in 1803. An icosahedral globe appeared in 1851. Polyhedral globes cheaply constructed from cardboard were popular for a time in Europe.
Projections based on dihedra begin appearing with the Peirce quincuncial projection in 1879, Guyou hemisphere-in-a-square projection in 1887, and Adams hemisphere-in-a-square projection in 1925. Although the dihedra are not traditional polyhedra they are spherical polyhedra, and the methods used in these projections are also used in other polyhedral projections. In the same work as the hemisphere-in-a-square projection, Adams created maps depicting the entire globe in a rhombus, hexagon, and hexagram.
Bernard J. S. Cahill invented the "butterfly map", based on the octahedron, in 1909. This was generalized into the Cahill–Keyes projection in 1975 and the Waterman butterfly projection in 1996. Cahill's work was also influential on Fuller's Dymaxion maps: Fuller's first version, based on a cuboctahedron, was published in 1943, and his second, based on an icosahedron, was published in 1954.
In 1965, Wellman Chamberlin (also known for his Chamberlin trimetric projection) and Howard E. Paine of the National Geographic Society designed a polyhedral map based on the 12 equal pentagon faces of a dodecahedron. 20 years later, Chamberlin and Paine used that polyhedral map in "Global Pursuit", a board game intended to teach geography to children.
The quadrilateralized spherical cube was devised in 1975 for the Cosmic Background Explorer project.
Gallery
See also
HEALPix, which is not strictly a polyhedral map projection
List of map projections
References
Map projections | Polyhedral map projection | [
"Mathematics"
] | 817 | [
"Map projections",
"Coordinate systems"
] |
73,816,427 | https://en.wikipedia.org/wiki/Blow%20Up%20%28Dutch%20TV%20series%29 | Blow Up is a Dutch television show in which contestants compete in balloon modelling. Martijn Krabbé and Chantal Janzen presented the first season of the show in 2022. Krabbé and Leonie ter Braak presented the second season of the show.
Balloon artist Guido Verhoef served as judge in the first season of the show, together with a guest judge in each episode.
The format of the show was sold to Australia and Germany. The Australian version is hosted by Stephen Curry and Becky Lucas.
References
2022 Dutch television series debuts
Dutch-language television shows
RTL 4 original programming
Dutch reality television series
2020s reality television series
Balloons | Blow Up (Dutch TV series) | [
"Chemistry"
] | 134 | [
"Balloons",
"Fluid dynamics"
] |
73,816,507 | https://en.wikipedia.org/wiki/5%20Leonis%20Minoris | 5 Leonis Minoris (5 LMi), commonly referred to as HD 75332, is a yellow-white star in the northern constellation of Lynx, close to the border with Cancer. With an apparent magnitude of 6.210, it is near the limit for naked eye observation, and can be seen faintly under very dark skies. As such, the Bright Star Catalogue lists it as HR 3499. It is located at a distance of according to Gaia EDR3 parallax measurements, and is moving farther away at a heliocentric radial velocity of 4.212 km/s.
Properties
This is an ordinary F-type main-sequence star with the stellar classification F7V, meaning it is fusing hydrogen into helium at its core to generate energy. It is 24% larger than the Sun and 21% more massive, emitting 2.11 times the luminosity of the Sun from its photosphere at an effective temperature of . It is roughly 40% the age of the Solar System at 1.88 billion years old. Its physical properties are similar to that of some of the hotter exoplanet-hosting stars, such as Iota Horologii, HD 52265, and HD 209458.
Compared to the Sun, the star is overall slightly more enriched in elements heavier than hydrogen and helium, with a metallicity measured at [M/H] = dex (i.e., % richer). It is about 120 times richer in lithium ([Li/H]= dex), and also substantially enhanced in calcium, scandium, titanium, iron, and nickel, but somewhat poor in nitrogen (10−0.11 ≈ 78% the solar abundance). Due to its high metal content, it was predicted in 2001 that a giant planet will almost certainly be found around 5 LMi. Likewise, a 2019 paper gave a 65% chance that the star is orbited by a planet with a mass greater than 0.0945 . However, no exoplanets have been discovered in orbit as of January 2021.
Stellar activity
In 2019, the star was discovered to exhibit cyclical chromospheric activity, measured by the Mount Wilson S-index, with a period of approximately 180 days. This is much shorter than the 11-year activity cycle of the Sun and bears resemblance to that displayed by other F-type stars including Tau Boötis, HD 16673, HD 49933, and 89 Leonis. A follow-up study in 2021 confirmed the short-term periodicity (~193.5 days), together with two longer cycles each lasting ~3.9 years and ~31.5 years. Additionally, their observations of the stellar magnetic field showed a rapid cycle with a period of approximately 1.06 years, also much shorter than the Sun's. In this regard it is again akin to τ Boo, which harbors a hot Jupiter (b), whereas 5 LMi does not. Such cycles are probably innate to late F-type stars and caused by their thin convection zones.
See also
List of star systems within 85–90 light-years
Notes
References
F-type main-sequence stars
Lynx (constellation)
Leonis Minoris, 05
BD+33 01765
075332
043410
3499
J08503222+3317061 | 5 Leonis Minoris | [
"Astronomy"
] | 687 | [
"Lynx (constellation)",
"Constellations"
] |
73,816,805 | https://en.wikipedia.org/wiki/Zygosaccharomyces%20rouxii | Zygosaccharomyces rouxii is a species of yeast in the genus Zygosaccharomyces. Initially described as Saccharomyces rouxii by Boutroux in 1883, it was then moved to the genus Zygosaccharomyces in the work of Barnett et al. It is remarkably tolerant of high concentrations of sugar or salt, making it a spoilage agent of otherwise stable foods, but also present in fermentation of products such as soy sauce or balsamic vinegar.
Description
It is a diploid, homothallic, and osmophilic (capable of withstanding high osmotic pressures, such as high concentrations of sugar) yeast. It produces ethanol by alcoholic fermentation.
It is found on grapes, in urine, fermented foods, syrups (maple), honey, grape juice concentrate, marzipan, candied fruit, miso, marmalade, and wine.
It is capable of fermenting dextrose (D-glucose) and maltose but has no fermentation activity on sucrose and lactose. Cells are small, round or oval and linked together in chains. It is particularly tolerant of a wide range of acidity and sugar and salt concentration but is sensitive to temperatures above 35°C unless protected by a small amount of sugar in the medium.
In lab, is grown on malt extract agar. After 3 days at 25°C, cells are spheroidal to cylindrical, either singly or in pairs or sometimes in small clumps.
History
Two collaborators of Louis Pasteur are the origin of the discovery of this new yeast: it was isolated by Émile Roux from fermenting fruit juice and was described as Saccharomyces rouxi by Léon Boutroux in 1883.
It has been described multiple times under different names. See the Catalogue of Life checklist.
It has been genetically sequenced in 2009.
Usage
In food, this yeast is used in the fermentation of soybeans during the manufacture of soy sauce and miso where it plays an important role in the development of aromas. It is also present in the fermentation of traditional Italian balsamic vinegar.
In the manufacture of soy sauce, soybeans and grain are inoculated with mold cultures such as Aspergillus oryzae to make what is called koji, then it is put in brine and seeded with the lactic acid bacteria Tetragenococcus halophilus (=Pediococcus halophilus) which produces lactic acid then with Zygosaccharomyces rouxii which ferments alcohol.
Miso is obtained from a cereal koji seeded with a mold (Aspergillus oryzae) which is then salted and fermented by lactic acid bacteria. (Enterococcus, Pediococcus...) and yeasts like Z. rouxii.
Z. rouxii produces alcoholic fermentation and hydrolyzes various amino acids into their respective alcohols. It synthesises aromatic components HEMF and HDMF.
Z. rouxii can cause spoilage of certain high-sugar and high-salt foods such as condensed milk, fruit juices, jam, pastries and salad dressings. It causes alcoholic fermentation: the alteration of the product is manifested by an alcoholic taste and especially by an intense gas release which makes the drink fizzy and which can cause the packaging to swell.
Notes
References
External links
Osmophiles
Saccharomycetaceae
Yeasts
Fungi described in 1883
Fungus species | Zygosaccharomyces rouxii | [
"Biology"
] | 751 | [
"Yeasts",
"Fungi",
"Fungus species"
] |
73,817,188 | https://en.wikipedia.org/wiki/Global%20Human%20Settlement%20Layer | The Global Human Settlement Layer (GHSL) is a project from the European Commission that creates global geographical data about the evolution of human habitation on Earth. This in the form of population density maps, built-up maps, and settlement maps. This information is produced using new geographic data mining tools and knowledge and analytics based on empirical data.
The GHSL processing framework uses a range of data, including census data, archives of fine-scale global satellite imagery, and voluntarily provided geographic information. Data is processed automatically to produce analytics and knowledge that methodically and objectively describe the existence of people and developed infrastructure. The GHSL maps human presence on Earth, sourcing information from 1975 and up to 2030.
Background
In 2010–2011, the JRC Directorate E "Space, Security & Migration" developed the initial version of the GHSL concept, which was used to create the Atlases of the Human Planet. The JRC is currently supporting GHSL activities through its scientific working plans and is collaborating with the Directorate-General for Regional and Urban Policy (DG REGIO) and the Directorate-General for Defence Industry and Space (DG DEFIS) to develop a routine and operational monitoring system.
References
External links
Official Website
World Population Density Interactive Map of urban settlements stretching from Washington to Boston
GHSL at developers.google.com
Satellite imagery
Global Human Settlement Layer
Global Human Settlement Layer
European Commission projects
Population ecology
Demography
Data mapping | Global Human Settlement Layer | [
"Technology",
"Engineering",
"Environmental_science"
] | 294 | [
"Data mapping",
"Data engineering",
"Data",
"Demography",
"Geographic data and information",
"Environmental social science"
] |
73,817,693 | https://en.wikipedia.org/wiki/Blanton%20Forest | Blanton Forest is a nature preserve and old-growth forest in the U.S. state of Kentucky, located in the Appalachian Mountains and protecting 3,510 acres of forest, including 2,200 acres that have never been logged. The dominant plant community is the Appalachian mixed mesophytic forest.
History
Blanton Forest was purchased in 1928 by Grover and Oxie Blanton, for whom the forest is named, and was inherited by their daughters with the understanding that the forest would be protected from logging. In 1995 the Kentucky Natural Lands Trust formed to continue the Blanton family's legacy by protect the old-growth forest, which is the largest in the state of Kentucky and one of only 13 large tracts of old-growth forest remaining in the eastern USA.
In 2016 the forest was recognized as part of the Old-Growth Forest Network.
References
Old-growth forests
Forests of Kentucky
Protected areas of Kentucky | Blanton Forest | [
"Biology"
] | 188 | [
"Old-growth forests",
"Ecosystems"
] |
73,818,146 | https://en.wikipedia.org/wiki/V692%20Coronae%20Australis | V692 Coronae Australis (HD 166596; HR 6804; 3 G. CrA), or simply V692 CrA, is a whitish-blue hued variable star located in the southern constellation Corona Australis. It has a maximum apparent magnitude of 5.46, making it faintly visible to the naked eye. The object is located relatively far at a distance of approximately 1,900 light years based on Gaia DR3 parallax measurements, but it is approaching the Solar System with a fairly constrained heliocentric radial velocity of . At its current distance, V692 CrA's brightness is heavily diminished by 0.46 magnitudes due to extinction due to interstellar dust. Its absolute magnitude depends on the source: Westin (1985) gave a value of −6.44 while the extended Hipparcos catalogue gave a value of −2.26.
Astronomers Carlos and Mercedes Jaschek along with a colleague listed HD 166596 as a Be star in 1964. However, its status as an Ap star was not observed until 1979 by astronomers N. Vogt and A.M Faundez. A year later, HD 166596 was observed to be variable and it had a period of 1.67 days. In 1981, its variability was confirmed and it was given the variable star designation V692 Coronae Australis—the 692nd variable star in Corona Australis. The star might have a shorter period of 49.8 hours.
V692 CrA has a stellar classification of B2 III or B1.5 IIIp, both indicating that it is a slightly evolved B-type giant star. The second classification indicates that V692 CrA has peculiarities in its spectrum. It has 7.35 times the mass of the Sun and 12.6 times the Sun's radius. It radiates at a bolometric luminosity 4,181 times that of the Sun from its photosphere at an effective temperature of . V692 CrA is estimated to be 31.6 million years old and it spins rapidly with a projected rotational velocity of .
References
B-type giants
Ap stars
SX Arietis variables
Coronae Australis, V692
Corona Australis
Coronae Australis, 3
CD-41 12534
166596
089290
6804
Be stars | V692 Coronae Australis | [
"Astronomy"
] | 490 | [
"Corona Australis",
"Constellations"
] |
73,818,274 | https://en.wikipedia.org/wiki/UK%20Young%20Academy | The UK Young Academy (UKYA) is a national interdisciplinary membership organisation that brings together UK-based early career researchers, professionals and innovators from a wide range of sectors, enabling them to collaborate to make a positive difference in the UK and globally. Its work programmes include member-led activities and initiatives that work to address the challenges the world is facing at a national and international level.
Launch
The Royal Society launched the academy in June 2022, in collaboration with seven senior partner academies across the UK and Ireland. The Royal Society solicited applications for membership. These academies are:
The Royal Society
The British Academy
The Academy of Medical Sciences
The Learned Society of Wales
The Royal Academy of Engineering
The Royal Irish Academy
The Royal Society of Edinburgh
Operation
It is currently operating under the auspices of the Royal Society in first instance. It joins the global initiative of Young Academies, with the UK Young Academy becoming the 50th to join the movement. Its founding cohort of 67 members started in January 2023. The second cohort of 32 were announced in March 2024. Membership is free, through a competitive selection process, and lasts for five-year terms.
An Executive Group, comprising elected representatives of the membership, forms the leadership team and is responsible for working with the members to implement the Young Academy’s strategy and work programmes. The Executive Group seven members, announced in 2023, are:
Jahangir Alom, Barts Health NHS Trust
Sandeep Sandhu, Innovate UK Business Connect
Denis Newman-Griffis, University of Sheffield
Linda Oyama, Queen's University Belfast
Edward Pyzer-Knapp, IBM
Sophoe Meekings, University of York
Amy Vincent, Newcastle University
See also
Global Young Academy
World Association of Young Scientists
Young Academy of Europe
Young Academy of Scotland
References
Organisations based in the United Kingdom
2022 establishments in the United Kingdom
National academies of sciences
Scientific organisations based in the United Kingdom
Youth organisations based in the United Kingdom
British Academy
Royal Academy of Engineering
Royal Irish Academy
Royal Society
Royal Society of Edinburgh
Youth science | UK Young Academy | [
"Engineering"
] | 411 | [
"Royal Academy of Engineering",
"National academies of engineering"
] |
73,818,409 | https://en.wikipedia.org/wiki/Grassroots%20innovation | Grassroots Innovation is the voluntary generation and development of innovations by any member of an organization,
regardless of function or seniority.
It is considered a form of bottom-up innovation (see Top-down and bottom-up design), whereby innovation resides 'deep in the bowels' of an organization, i.e., it is seen as a responsibility of all members of an organization.
Advantages
Grassroots innovation offers several benefits to companies:
Caters to employees' need for self-determination, boosting their intrinsic motivation
Leverages the creativity of employees that would otherwise not contribute to innovation efforts
Helps employees learn how to generate, mature and implement innovation ideas
Stimulates networking and connections among employees who may not often work together
Leverages cross-functional synergies and frontline knowledge to generate more customer-centric innovations
Risks
Grassroots innovation is, however, associated with two important risks:
Higher autonomy means employees may drift from firm-wide goals
High coordination costs, which means that without a careful process design, companies may become disappointed with the results
Hard to keep all ideators motivated and properly incentivized
Other uses of the term
Researchers in the fields of sustainability and technology have used the term grassroots innovation to refer to "a network of activists and organizations generating novel bottom-up solutions for sustainable development and sustainable consumption; solutions that respond to the local situation and the interests and values of the communities involved", or as innovations generated by economically disadvantaged people who find practical and creative solutions for the needs of people at the bottom of the pyramid. These definitions are logically consistent with the definition above but refer to the society or community as the macro-unit of analysis, rather than a firm or organization. As such, they are a direct manifestation of the broader concept of grassroots movements in society.
References
Innovation
Workplace programs
Organizational behavior
Workplace
Employee relations | Grassroots innovation | [
"Biology"
] | 366 | [
"Behavior",
"Organizational behavior",
"Human behavior"
] |
73,818,522 | https://en.wikipedia.org/wiki/Bich-Yen%20Nguyen | Bich-Yen Nguyen is a Vietnamese electronics engineer specializing in advanced materials and technologies for integrated circuits. Educated in the US, she works in France as a senior fellow for Soitec, working on silicon on insulator technology.
Education and career
Nguyen is the daughter of a South Vietnamese soldier who died when she was young, leaving her family poor. Despite this hardship, her mother continued to send her to a boarding school, and then to the University of Texas at Austin in the US for her university education. While she was there, the Fall of Saigon in 1975 left the rest of her family as refugees, and she helped them resettle in the US. She graduated in 1977, with a bachelor's degree in chemical engineering.
After working briefly for the city of Austin, Texas, she began working for Motorola in 1980. Her work there included the development of the multiple-independent-gate field-effect transistor (MIGFET), as well as CMOS technology. As head of advanced transistor development activities at 2004 Motorola spinoff Freescale Semiconductor, she participated in the Crolles Alliance, an international collaboration on CMOS that extended from 2002 to 2007. She was hired by Soitec as a substrate design engineer in 2007.
Recognition
Before leaving Motorola, Nguyen was a Motorola Distinguished Innovator and Dan Noble Fellow. She was one of the winners of the 2004 Women of Color Technology Awards. Her work as a vice president of Soitec was highlighted in the 2010 video production Paris by Night 99, honoring successful Vietnamese expatriates worldwide.
She was named an IEEE Fellow, in the 2020 class of fellows, "for contributions to silicon on insulator technology".
References
External links
Year of birth missing (living people)
Living people
Vietnamese engineers
Electronics engineers
Women electrical engineers
University of Texas at Austin alumni
Fellows of the IEEE | Bich-Yen Nguyen | [
"Engineering"
] | 375 | [
"Electronics engineers",
"Electronic engineering"
] |
73,818,852 | https://en.wikipedia.org/wiki/Agaricus%20lanatoniger | Agaricus lanatoniger is an agaric fungus in the family Agaricaceae, endemic to New Zealand.
Taxonomy
A. lanatoniger was first described in 1974 by Belgian mycologist Paul Heinemann and collected by Egon Horak in December 1967. The holotype specimen was collected in the Westland Province, of New Zealand by Lake Haupiri, underneath red beech (Nothofagus fusca) and rimu (Dacrydium cupressinum) trees. The original paper reference number was incorrect, but is correctly listed as PDD 27107 in a report on New Zealand Agaricus species in 1999.
Description
The pileus of Agarcius lanatoniger can vary from a spherical to a convex shape. Smaller specimens tend to have more spherical pileus, while larger are more flattened convex shape, although both have round shape when viewed from above. The dark brown, felt-like pileus or cap can be up to wide in diameter.
The gills consist of thin pink filaments, stemming from the underside of the pileus without touching the stem. This forms a small ring around the stem less than long. About a third of the length of the stem is a thick skirt. This extends out from the stem. Above the skirt, the stem is tan or pale colour. While underneath, the colour transitions from light brown to dark brown or black like the cap's colour.
The spores are opaque chocolate brown, ellipsoid and 5,3-6,0(6,5) X 3,4-3,7 μm in size. The basidia are 18-24 X 6,5-7,2 μm, transparent and have 4 spores each. The gills have abundant transparent cheilocystidia which are pear to club shaped and 20-25 X 7-12 μm.
The stem ranges from in length and with a diameter of , generally thicker toward the base. Inside the stem is a white, hollow column beginning at gill level but sealed at the bottom. Beneath the ground, the bulbous shape has many small root-like filaments. The stem's insides are white with a hollow center.
Similarity to Agaricus purpureoniger
The sequence of A. lanatoniger, when compared to A. purpureoniger differed only by one nucleotide, suggesting that they be the same species. When physically compared, the A. purpureoniger is more purple. However, over the last three decades, all samples of A. purpureoniger have been found in similar locations as A. lanatoniger, specifically in the northwestern regions of both the New Zealand islands.
Habitat
Agaricus lanatoniger has been found in nine different terrestrial locations primarily in New Zealand The mean annual temperature for all locations ranges from . Due to New Zealand's temperate climate, this fluctuates throughout its four distinct seasons. Most samples show A. lanatoniger in the ground of forests, however, the type of forest has not been noted.
Etymology
Lanatoniger originates from the Latin "lanatus" (adj) meaning wooly or downy. This refers to the felt-like texture of its pileus.
References
lanatoniger
Edible fungi
Fungi described in 1974
Fungi of New Zealand
Fungus species | Agaricus lanatoniger | [
"Biology"
] | 680 | [
"Fungi",
"Fungus species"
] |
73,820,067 | https://en.wikipedia.org/wiki/St.%20Lucia%20Electricity%20Services | The St. Lucia Electricity Services Limited (LUCELEC) is an electric utility company of Saint Lucia.
History
The company was established in 1964. The company went public on 11 August 1994.
Finance
In 2022, the company revenue reached EC$134,189,000.
Power stations
Cul De Sac Power Station
References
External links
1964 establishments in Saint Lucia
Companies of Saint Lucia
Electric power companies
Electric power in Saint Lucia
Public utilities established in 1964 | St. Lucia Electricity Services | [
"Engineering"
] | 90 | [
"Electrical engineering organizations",
"Electric power companies"
] |
73,820,108 | https://en.wikipedia.org/wiki/Roam%20%28software%29 | Roam is a California-based productivity and note-taking application developed by Roam Research Inc. The system is built on a directed graph, which frees it from the constraints of the classic filesystem tree. It is viewed as a competitor to Notion.
See also
Collaborative real-time editor
Document collaboration
Obsidian (software)
Notion
References
External links
Note-taking software
Collaborative real-time editors
Collaborative software
Proprietary wiki software
Software companies based in California
Business software | Roam (software) | [
"Technology"
] | 92 | [
"Collaborative real-time editors"
] |
73,820,750 | https://en.wikipedia.org/wiki/Trihydrogen%20oxide | Trihydrogen oxide is a predicted inorganic compound of hydrogen and oxygen with the chemical formula . This is still a hypothetical compound, one of the unstable hydrogen polyoxides. It is hypothesized that the compound could constitute a thin layer of metallic liquid around the cores of Uranus and Neptune, and that this could be the source of their magnetic fields. Calculations indicate the stability of in solid, superionic, and fluid metallic states at the deep interior conditions of these planets.
Synthesis
Trihydrogen oxide has not been observed experimentally as of 2023, but its existence is predicted by calculation using the CALYPSO method. The compound should be stable in the pressure range 450–600 GPa and could be produced by the reaction:
Physical properties
The compound is considered not a true molecular trihydrogen oxide compound. Instead, each oxygen atom is linked by a strong (covalent) bond to only two hydrogen atoms, as a water molecule, and there are molecules of dihydrogen inserted in the voids of the water molecules network. Structurally, it is thus a stoichiometric combination.
At 600 GPa and 7000 K, the compound density is calculated to be 4.3 g/cm3. Molecular dynamics simulations were carried out at constant density for different temperatures:
At 1000 K, is an orthorhombic crystalline solid (space group Cmca).
At 1250 K, this solid passes into a superionic state.
The compound liquefies at 5250 K, and the liquid should have metallic-like electrical conductivity.
In the Solar system
The magnetic fields of both Uranus and Neptune are special—non-dipolar and non-axisymmetric. This fact can be explained if the magnetic fields are produced by dynamo effect within a sufficiently thin conductive layer. However, the origin of the fields is still problematic because the cores of these planets are probably solid (thus too rigid), and the thick mantles of ice are too poorly conductive to create the effect.
References
Inorganic compounds
Oxides
Polyoxides
Oxoacids
Hypothetical chemical compounds
Theoretical chemistry | Trihydrogen oxide | [
"Chemistry"
] | 430 | [
"Inorganic compounds",
"Oxides",
"Hypotheses in chemistry",
"Salts",
"Theoretical chemistry",
"nan",
"Hypothetical chemical compounds"
] |
73,823,969 | https://en.wikipedia.org/wiki/Cyber%20Resilience%20Act | The Cyber Resilience Act (CRA) is an EU regulation for improving cybersecurity and cyber resilience in the EU through common cybersecurity standards for products with digital elements in the EU, such as required incident reports and automatic security updates. Products with digital elements mainly are hardware and software whose "intended and foreseeable use includes direct or indirect data connection to a device or network".
After its proposal on 15 September 2022 by the European Commission, multiple open source organizations criticized CRA for creating a "chilling effect on open source software development". The European Commission reached political agreement on the CRA on 1 December 2023, after a series of amendments. The revised bill introduced the "open source steward", a new economic concept, and received relief from many open source organizations due to its exception for open-source software, while Debian criticized its effect on small businesses and redistributors. The CRA agreement received formal approval by the European Parliament in March 2024. It was adopted by the Council on 10 October 2024.
Purposes and motivations
The background, purposes and motivations for the proposed policy include:
Consumers increasingly become victims to security flaws of digital products (e.g. vulnerabilities), including of Internet of Things devices or smart devices.
Ensuring that digital products in the supply chain are secure is important for businesses, and cybersecurity often is a "full company risk issue".
Potential impacts of hacking include "severe disruption of economic and social activities across the internal market, undermining security or even becoming life-threatening".
Secure by default principles would impose a duty of care for the lifecycle of products, instead of e.g. relying on consumers and volunteers to establish a basic level of security. The new rules would "rebalance responsibility towards manufacturers".
Cyberattacks have led "to an estimated global annual cost of cybercrime of €5.5 trillion by 2021".
The rapid spread of digital technologies means rogue states or non-state groups could more easily disrupt critical infrastructures such as public administration and hospitals.
According to The Washington Post, the CRA could make the EU a leader on cybersecurity and "change the rules of the game globally".
Implementation and mechanisms
The policy requires software that are "reasonably expected" to have automatic updates should roll out security updates automatically by default while allowing users to opt out. When feasible, security updates should be separated from feature updates. Companies need to conduct cyber risk assessments before a product is put on the market and retain its data inventory and documentation throughout the 10 years after being put on market or its support period, whichever is longer. Companies would have to notify EU cybersecurity agency ENISA of any incidents within 24 hours of becoming aware of them, and take measures to resolve them. Products carrying the CE marking would "meet a minimum level of cybersecurity checks".
About 90% of products with digital elements fall under a default category, for which manufacturers will self-assess security, write an EU declaration of conformity, and provide technical documentation. The rest are either "important" or "critical". Security-important products are categorized into two classes of risks. Products assessed as 'critical' will need to undergo external audits.
Once the law has passed, manufacturers would have two years to adapt to the new requirements and one year to implement vulnerability and incident reporting. Failure to comply could result in fines of up to €15 million or 2.5 percent of the offender's total worldwide annual turnover for the preceding financial year. Fines do not apply to non-commercial open-source developers.
Euractiv has reported on novel drafts or draft-changes that includes changes like the "removal of time obligations for products' lifetime and limiting the scope of reporting to significant incidents". The first compromise amendment will be discussed on 22 May 2023 until which groups reportedly could submit written comments. Euractiv has provided a summary overview of the proposed changes.
The main political groups in the European Parliament are expected to agree on the Cyber Resilience Act at a meeting on 5 July 2023. Lawmakers will discuss open source considerations, support periods, reporting obligations, and the implementation timeline. The committee vote is scheduled for 19 July 2023.
The Spanish presidency of the EU Council has released a revised draft that simplifies the regulatory requirements for connected devices. It would reduce the number of product categories that must comply with specific regulations, mandate reporting of cybersecurity incidents to national CSIRTs, and include provisions for determining product lifetime and easing administrative burdens for small companies. The law also clarifies that spare parts with digital elements supplied by the original manufacturer are exempt from the new requirements.
The Council text further stipulates that prior to seeking compulsory certification, the European Union executives must undertake an impact assessment to evaluate both the supply and demand aspects of the internal market, as well as the member states' capacity and preparedness for implementing the proposed schemes.
On June 25, 2024, the Czech National Office for Cyber and Information Security (NÚKIB) announced steps to implement the Cyber Resilience Act (CRA), including a regulation expected in autumn 2024, with enforcement starting in late 2027 after a three-year transition. This regulation will require manufacturers of digital products to enhance cybersecurity throughout the product lifecycle. NÚKIB will also hold consultations with manufacturers of significant and critical products from June 25 to July 17, 2024, to develop technical specifications and gather feedback.
Reception
Initially, the proposed act was heavily criticized by open-source advocates.
Multiple open source organizations like the Eclipse Foundation, the Open Source Initiative (OSI), and The Document Foundation have signed the open letter "Open Letter to the European Commission on the Cyber Resilience Act", asking policy-makers to change the under-representation of the open source community. It finds that with the policy "[free and open source software,] more than 70% of the software in Europe[,] is about to be regulated without an in-depth consultation" and if implemented as written (as of April) would have a "chilling effect on open source software development as a global endeavour, with the net effect of undermining the EU's own expressed goals for innovation, digital sovereignty, and future prosperity". The Apache Software Foundation published a similar statement, and the OSI submitted this information to the European Commission's request for input.
Although Mozilla "welcome[s] and support[s] the overarching goals of the CRA", it also criticised the proposal for unclear references to "commercial activity" that could include many open source projects (a viewpoint Ilkka Turunen of Computer Weekly repeated), misalignment with other EU rules, and requirements for the disclosure of unmitigated vulnerabilities.
Steven J. Vaughan-Nichols of The Register argued the CRA's "underlying assumption is that you can just add security to software" while "[m]any open source developers have neither the revenue nor resources to secure their programs to a government standard".
CCIA Europe warned that "the resulting red tape from the approval process could hamper the roll-out of new technologies and services in Europe".
Amendments were released on 1 December 2023, as part of political agreement between co-legislators, to the acclaim of many open-source advocates. As Mike Milinkovich, executive director of the Eclipse foundation, wrote:
The OSI noted Debian's statement that many small businesses and solo developers would have trouble navigating the act when redistributing open source software remained unaddressed. Apache reviewed the changes positively while worrying about applicability of the CRA on potentially critical open-source components and stressing the importance of collaboration with international standards bodies to ease certification of software.
See also
Artificial Intelligence Act
Cyber Security and Resilience Bill—proposed UK legislation
Consumer protection
Cyber self-defense
List of data breaches
List of security hacking incidents#
Sustainable design
Standardization
References
External links
Cyber Resilience Act on EUR-Lex
Cyber Resilience Act Shaping Europe's digital future landing page of the EU Commission (DG CONNECT)
Procedure 2022/0272/COD on EUR-Lex
Procedure 2022/0272(COD) on ŒIL
European Union data protection law
Computing legislation
2024 in law
Computer security
Internet of things
IT infrastructure
2024 in politics
2024 in computing | Cyber Resilience Act | [
"Technology"
] | 1,731 | [
"Information technology",
"IT infrastructure"
] |
73,824,591 | https://en.wikipedia.org/wiki/Attachment%20Play | Attachment Play is a term created by developmental psychologist, Aletha Solter and the title of one of her books. It is one aspect of her Aware Parenting approach. The term refers to nine specific kinds of parent/child play that can strengthen attachment, solve behavior problems, and help children recover from traumatic experiences. These forms of play incorporate many traditional play therapy techniques as well as some newer ones.
Research basis
The forms of play are based on attachment theory, and their effectiveness is supported by research in child development, neurobiology, and psychotherapy. For example, nondirective child-centered play has been studied for decades and has been shown to help children become less aggressive. It can also help to reduce learning difficulties while increasing social competence. Symbolic play with specific props or themes is based on exposure therapy techniques and can help children overcome traumatic experiences.
Contingency play is an important activity in helping traumatized children feel empowered, and the therapeutic value of separation games such as peek-a-boo has been recognized for decades. Playful activities with body contact can strengthen parent/child attachment and meet children's need for touch, which reduces stress while stimulating growth and healing. Cooperative games and activities (with or without touch) are especially effective in fostering cooperative behavior in children.
Laughter is an important component of several of these forms of play. In addition to strengthening parent/child attachment, laughter can help reduce anxiety and strengthen the immune system., Nonsense play (humor based on exaggeration, mistakes, or general silliness) has been shown to decrease a child's anxiety during medical interventions. Power-reversal play (such as a pillow fight in which the adult lets the child “win”) also involves laughter and can help to strengthen attachment while reducing anger and aggressive behavior.
A controlled pilot study was conducted in Australia to evaluate the effectiveness of three kinds of Attachment Play in a brief parent education program. The researchers found that the program increased parents’ feelings of self-efficacy Another pilot study was done in Ireland to teach Attachment Play to social workers, who then trained parents to implement the approach with their children. The training helped parents engage playfully with children, strengthen attachment, enhance cooperation, reduce behavior problems, and avoid the use of punishment.
References
External links
Attachment theory
Play (activity)
Child development | Attachment Play | [
"Biology"
] | 465 | [
"Play (activity)",
"Behavior",
"Human behavior"
] |
73,825,961 | https://en.wikipedia.org/wiki/Network%20Coordinate%20System | A Network Coordinate System (NC system) is a system for predicting characteristics such as the latency or bandwidth of connections between nodes in a network by assigning coordinates to nodes. More formally, It assigns a coordinate embedding to each node in a network using an optimization algorithm such that a predefined operation estimates some directional characteristic of the connection between node and .
Uses
In general, Network Coordinate Systems can be used for peer discovery, optimal-server selection, and characteristic-aware routing.
Latency Optimization
When optimizing for latency as a connection characteristic i.e. for low-latency connections, NC systems can potentially help improve the quality of experience for many different applications such as:
Online Games
Forming game groups such that all the players are close to each other and thus have a smoother overall experience.
Choosing servers as close to as many players in a given multiplayer game as possible.
Automatically routing game packets through different servers so as to minimize the total latency between players who are actively interacting with each other in the game map.
Content delivery networks
Directing a user to the closest server that can handle a request to minimize latency.
Voice over IP
Automatically switch relay servers based on who is talking in a few-to-many or many-to-many voice chat to minimize latency between active participants.
Peer-to-peer networks
Can use the latency-predicting properties of NC systems to do a wide variety of routing optimizations in peer-to-peer networks.
Onion routing networks
Choose relays such as to minimize the total round trip delay to allow for a more flexible tradeoff between performance and anonymity.
Physical positioning
Latency correlates with the physical distances between computers in the real world. Thus, NC systems that model latency may be able to aid in locating the approximate physical area a computer resides in.
Bandwidth Optimization
NC systems can also optimize for bandwidth (although not all designs can accomplish this well). Optimizing for high-bandwidth connections can improve the performance of large data transfers.
Sybil Attack Detection
Sybil attacks are of much concern when designing peer-to-peer protocols. NC systems, with their ability to assign a location to the source of traffic can aid in building systems that are Sybil-resistant.
Design Space
Landmark-Based vs Decentralized
Almost any NC system variant can be implemented in either a landmark-based or fully decentralized configuration. Landmark-based systems are generally secure so long as none of the landmarks are compromised, but they aren't very scalable. Fully decentralized configurations are generally less secure, but they can scale indefinitely.
Euclidean Embedding
This design assigns a point in -dimensional euclidean space to each node in the network and estimates characteristics via the euclidean distance function where represents the coordinate of node .
Euclidean Embedding designs are generally easy to optimize.
The optimization problem for the network as a whole is equivalent to finding the lowest energy state of a spring-mass system where the coordinates of the masses correspond to the coordinates of nodes in the network and the springs between the masses represent measured latencies between nodes.
To make this optimization problem function work in a decentralized protocol, each node exchanges its own coordinates with those of a fixed set of peers and measures the latencies to those peers, simulating a miniature spring-mass system where all the masses representing the coordinates of the peers and each mass is connected via a single spring to the node's own "mass" which when simulated, gives a more optimal value for the node's coordinate. All these individual updates allow the network as a whole to form a predictive coordinate space by collaboratively.
The laws of Euclidean space require certain characteristics of the distance function to hold true, such as symmetry (measuring from should give the same result as from ) and the triangle inequality . No real-world network characteristics completely satisfy these laws, but some do more than others and NC systems using euclidean embedding are somewhat accurate when run on datasets containing violations of these laws.
Notable Papers: GNP, PIC Vivaldi, Pharos
Matrix Factorization
The matrix factorization design imagines the entire network as represented by an incomplete matrix where is the total number of nodes in the network, and any element of the matrix at the intersection between row and column of the matrix represents a directional latency measurement from node to node . The goal is to estimate the numbers in the unfilled squares of the matrix using the squares that are already filled in, i.e. performing matrix completion.
To estimate a specific latency between two nodes, this method uses the dot product where / represents a point in a -dimensional inner product space.
NC system designs using matrix factorization are generally more complicated than their euclidean counterparts.
In the centralized variant, matrix completion can be performed directly on a set of landmarks which have measured latency to every other landmark in a set, thus creating a complete matrix representing the landmark network. This matrix can then be factored on a single computer using non-negative matrix factorization (NNMF) into two matrices and such that . Since matrix multiplication is essentially doing the dot product for each row and column of the input matrices, coordinates for each landmark can be represented by two "in" and "out" vectors ( and ) taken respectively from the th row of and the th column of . With this, latencies between two landmarks can be approximates by a simple dot product: . Any node that wants to figure out their own coordinates can simply measure the latency to some subset of all the landmarks, re-create a complete matrix using the landmark's coordinates, and then perform NNMF to calculate their own coordinate. This coordinate can then be used with any other node (landmark or otherwise) to estimate latency to any other coordinate that was calculated via the same set of landmarks.
The decentralized variant is decidedly simpler. For a given node, the goal is to minimize the absolute difference (or squared difference) between the measured latencies to the peers and the predicted latencies to the peers. The predicted latency is given by the same equation where is the outgoing vector of node and is the incoming vector of node . This goal (or loss function) can then be minimized using stochastic gradient descent with line search.
Notable Papers: IDES, Phoenix, DMFSGD
Tensor Factorization
Notable Papers: TNDP Leverage Sampling + Personal Devices
Relative Coordinates
Notable Papers: RMF
Alternatives
Network Coordinate Systems are not the only way to predict network properties. There are also methods such as iPlane and iPlane Nano which take a more analytical approach and try to mechanistically simulate the behavior of internet routers to predict by what route some packets will flow, and thus what properties a connection will have.
In The Wild
Vuze - BitTorrent Client
References
Computer networking
Peer-to-peer computing | Network Coordinate System | [
"Technology",
"Engineering"
] | 1,396 | [
"Computer networking",
"Computer science",
"Computer engineering"
] |
73,826,270 | https://en.wikipedia.org/wiki/%282-Nitrophenyl%29acetic%20acid | 2-Nitrophenylacetic acid is an organic compound used in organic synthesis that has also been used as an herbicide. It is a derivative of phenylacetic acid, containing a phenyl functional group, a carboxylic acid functional group, and a nitro functional group. It is an important reagent for many organic reactions, especially for the formation of heterocycles.
Synthesis
This compound may be prepared by the nitration of phenylacetic acid.
Applications
In organic synthesis, 2-nitrophenylacetic acid can be used as a protecting group for primary alcohols. The alcohol is esterified with 2-nitrophenylacetic acid, proceeding through the acid chloride or acid anhydride. The acid itself can also protect the alcohol through the Mitsunobu reaction: reacting the alcohol and the acid with diethyl azidocarboxylate and triphenylphosphine in dichloromethane. The protecting group is selectively removed using zinc and ammonium chloride, and is compatible with other existing alcohol protecting groups.
In addition, 2-nitrophenylacetic acid is a precursor for many heterocycles. Complete reduction of 2-nitrophenylacetic acid yields anilines, which quickly cyclize to form lactams. Partial reductive cyclization of the acids using weaker reducing agents forms hydroxamic acids.
Both of these processes are useful in the synthesis of many biologically active molecules. 2-nitrophenylacetic acid is a precursor of quindoline, which although it does not have many practical applications on its own, quindoline derivatives and modifications can be treated as enzyme inhibitors and anticancer agents.
Derivatives of 2-nitrophenylacetic acids are useful in total synthesis for their ability to form heterocycles. 2-nitrophenylacetic acid is a precursor to (−)-phaitanthrin D, a clinically useful molecule originally isolated from the Phaius mishmensis orchid. The carboxylic acid on the 2-nitrophenylacetic acid is first protected using menthol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCl), hydroxybenzotriazole(HOBt) and N,N-iisopropylethylamine(DIPEA). A pattern of reducing the nitro group to an amino group and subsequently forming amides by the addition to carboxylic acids (namely nitrobenzoic acid) occurs. Reductive cyclization of the subsequent product using hexamethyldisilazane, zinc chloride and dimethylformamide forms the disubstituted heterocycle present in the (−)-phaitantrin D molecule.
Outside of organic synthesis, 2-nitrophenylacetic acid has been used as an herbicide, as it displays selective herbicidal properties. It has also been used as an internal standard for measurement of salicylamide-O-acetic acid (an anti-asthma drug) using high performance liquid chromatography.
References
Phenylacetic acids
2-Nitrophenyl compounds
Herbicides | (2-Nitrophenyl)acetic acid | [
"Biology"
] | 698 | [
"Herbicides",
"Biocides"
] |
73,829,144 | https://en.wikipedia.org/wiki/Chuntex%20Electronic | Chuntex Electronic Co., Ltd., also known as CTX International, is a Taiwanese computer display manufacturer.
History
Chuntex Electronic Co., Ltd. was founded in 1981. Initially only a domestic manufacturer of cathode-ray-tube computer monitors within Taiwan, Chuntex expanded globally in 1986, establishing CTX International—their United States and primary international export subsidiary—that year, placing its headquarters in the City of Industry, California. In the United Kingdom, meanwhile, Chuntex established European offices in the Netherlands and the United Kingdom (Watford), employing 75 between them in 2004. Between the late 1980s to the late 1990s, the company acquired several overseas companies in the field of computer monitors and hardware, helping CTX grow to become one of the largest brands and OEM suppliers of monitors. In the early 1990s, they established their Opto subsidiary, which manufactured LCD monitors and projectors.
Chuntex's largest export market in 1995 was the United States (62 percent), compared with Asia (19 percent) and Europe (15 percent). Between fall 1992 and fall 1993, sales in CTX's wares grew from US$15.5 million to $27.2 million. The company earned US$11.5 million in profit on sales of roughly $250 million in 1998. By 1999, the company had 5,000 employees globally.
In August 1994, Chuntex purchased a 51-percent stake in Veridata Electronics, a computer company in Taiwanese, with Chuntex seeking the latter's laptop-manufacturing factory lines and workforce. After acquiring an even larger stake in Veridata, Chuntex then began selling computers branded under their own CTX name, as well as for other computer vendors, such as CompUSA in 1996, on an OEM basis. Though CTX was a relatively small name in the personal computer market at the time, the company initially earned a respectable profit from these systems, which included the sub-brands EzNote for their laptops and Nutopia for their desktop computers. However, in April 1999, the company reported losses equal to roughly half of their market capitalization, which the company attributed in large part to their laptop business. These losses put CTX in the red; in the process, they were the first major Taiwanese company to go bankrupt in 1999. Chuntex shortly after filed for reorganization protection in Taiwan. A few months later, the company announced that they would abandon manufacturing complete computer systems, in favor of focusing solely on monitor production while still selling some systems, albeit built by other companies and rebadged as CTX machines.
CTX remains active in Taiwan .
References
1981 establishments in Taiwan
1986 establishments in California
Companies based in Taipei
Computer companies established in 1981
Taiwanese brands
Computer monitors
Computer companies of Taiwan
Computer hardware companies | Chuntex Electronic | [
"Technology"
] | 575 | [
"Computer hardware companies",
"Computers"
] |
73,829,146 | https://en.wikipedia.org/wiki/Pluteus%20microspermus | Pluteus microspermus is a saprotrophic, mushroom-like (agaricoid) fungi in the Section Pluteus. It is often confused with Pluteus concentricus, a species endemic to New Zealand because P. concentricus also has concentric ridges on its cap (pileus). P. microspermus and P. concentricus can be differentiated by microscopy as the spores are different sizes. P. concentricus also has rougher material on its stipe.
Taxonomy
Pluteus microspermus was originally described by E. Horak in 1981 but first published in Volume 5 of The Fungi of New Zealand (2008). The holotype specimen was collected by E. Horak in 1981 from rotten wood or bark in the Waitākere Ranges near Piha, in New Zealand. The holotype is stored at The New Zealand Fungarium - Te Kohinga Hekaheka o Aotearoa in Auckland, New Zealand.
Description
Pluteus microspermus has concentric ridges on its cap (pileus). The pileus can be light or dark brown with a sooty appearance and is large, between 40 and 100 mm in diameter. The pileus is slightly curved at the margin with a broad central lump (umbonate), but older mushrooms may have a central depression. The margin of the pileus is not curled under. The center of the pileus may feel velvety to touch.
The gills (lamellae) are not attached to the stipe and change colour, from a pale white through to pink and finally dark brown on the edges. The lamellae are ventricose, extending downward from the cap, appearing swollen. They are fine and tufty at the edges (floccose-fimbriate). The spore print is pink, like other species in the Pluteus genus. The spores themselves are small (5-6 x 3-3.35 μm) and smooth and contribute to etymology.
The stipe can be 50–100 mm tall. The base of the stipe is bulbous (18 mm diameter) and narrows to around 7-10mm diameter near the cap. The stipe is white to light grey but covered with rough brown fibrous material (fibrils) that look scaley.
Habitat and distribution
Pluteus microspermus can be found growing on native broadleaf trees' rotten wood and bark, including Leptospermum, Kunzea, Fuscospora fusca and Lophozonia menziesii. P. microspermus is native and indigenous to New Zealand. It is found in both the North and South Islands. Its DNA sequence has also been observed in Argentina via soil samples. Fruit bodies (Basidiocarps) can be found during January to May (Summer to Autumn in New Zealand).
Etymology
The genus name Pluteus translates roughly to "shield", "shed" or "screen". The specific epithet microspermus means little (micro) spores (spermus).
Conservation status
Pluteus microspermus status is currently unknown due to a lack of data.
References
External links
Hidden Forest
Holotype photo
Fungi of New Zealand
Fungi described in 2008
microspermus
Fungus species | Pluteus microspermus | [
"Biology"
] | 677 | [
"Fungi",
"Fungus species"
] |
73,829,782 | https://en.wikipedia.org/wiki/John%20J.%20Monaghan | John J. Monaghan is a British mass spectrometrist and former editor of Rapid Communications in Mass Spectrometry.
Early life and career
Monaghan attended the University of Glasgow, where he completed his undergraduate degree in chemistry. He then undertook a PhD with Durward Cruickshank involving the study of gas-phase electron diffraction. After completing his studies he moved to work at Imperial Chemical Industries in Blackley site under the direction of mass spectrometrist John Beynon focusing on the analysis of textile dyestuffs. He was an early adopter and enthusiast of the Fast Atom Bombardment technique developed at the nearby UMIST by Mickey Barber and Don Sedgwick.
Other interests
Monaghan is an active member of the British Mass Spectrometry Society and has been given life membership for making a significant contribution to the practice of mass spectrometry in the UK. In 2003 the BMSS made John its first President with responsibility to promote the work done by the Society, particularly on the international stage and beyond the core MS community.
Monaghan has also been a member and president of the Peterloo Speakers Club in Manchester. He is also a keen cricketer and football referee.
References
Living people
Year of birth missing (living people)
British chemists
Mass spectrometrists
People associated with the University of Manchester
People associated with the University of Glasgow
Alumni of the University of Glasgow | John J. Monaghan | [
"Physics",
"Chemistry"
] | 288 | [
"Biochemists",
"Mass spectrometry",
"Spectrum (physical sciences)",
"Mass spectrometrists"
] |
73,829,878 | https://en.wikipedia.org/wiki/Spherical%20collapse%20model | The spherical collapse model describes the evolution of nearly homogeneous matter in the early Universe into collapsed virialized structures - dark matter halos. This model assumes that halos are spherical and dominated by gravity which leads to an analytical solution for several of the halos' properties such as density and radius over time.
The framework for spherical collapse was first developed to describe the infall of matter into clusters of galaxies. At this time, in the early 1970s, astronomical evidence for dark matter was still being collected, and it was believed that the Universe was dominated by ordinary, visible matter. However, it is now thought that dark matter is the dominating species of matter.
Derivation and key equations
The simplest halo formation scenario involves taking a sufficiently overdense spherical patch, which we call a proto-halo (e.g., Descjacques et al. 2018), of the early Universe and tracking its evolution under the effect of its self-gravity. Once the proto-halo has collapsed and virialized, it becomes a halo.
Since the matter outside this sphere is spherically symmetric, we can apply Newton's shell theorem or Birkhoff's theorem (for a more general description), so that external forces average to zero and we can treat the proto-halo as isolated from the rest of the Universe. The proto-halo has a density , mass , and radius (given in physical coordinates) which are related by .
To model the collapse of the spherical region, we can either use Newton's law or the second Friedmann equation, giving
The effect of the accelerated expansion of the Universe can be included if desired, but it is a subdominant effect.
The above equation admits the explicit solution
where is the maximum radius, assumed to occur at time , and is the quantile function of the Beta distribution, also known as the inverse function of the regularized incomplete beta function . The time
is the free-fall time, where .
Long before the derivation of this explicit solution, the spherical collapse equation has been known to admit a parametric solution
in terms of a parameter . The origin of time, , now occurs at a vanishing radius, and the time increases with increasing . The coefficients are given by the energy contents of the sphere (cf. equation 5.89 in Dodelson et al.). Initially the sphere expands at the rate of the Universe (), but then it slows down, turns around (), and ultimately collapses ().
If we split the density into a background and perturbation by , we can solve for the fully nonlinear perturbation
Initially , at the turn-around point , and at collapse .
Alternatively, if one considers linear perturbations, or equivalently small times , the above equation gives us an expression for linear perturbations
We can then extrapolate the linear perturbation into nonlinear regimes (more on the usefulness of this below). At turn-around and at collapse we get the spherical collapse threshold
Although the halo does not physically have an overdensity of 1.69 at collapse, the above collapse threshold is nevertheless useful. It tells us that if we model the initial (linear) density field and extrapolate into the future, wherever can be thought of as a collapsing region that will form a halo.
See also
Press–Schechter formalism – A mathematical model used to predict the number of dark matter halos of a certain mass.
References
Galaxies
Dark matter | Spherical collapse model | [
"Physics",
"Astronomy"
] | 703 | [
"Dark matter",
"Unsolved problems in astronomy",
"Concepts in astronomy",
"Galaxies",
"Unsolved problems in physics",
"Exotic matter",
"Astronomical objects",
"Physics beyond the Standard Model",
"Matter"
] |
73,832,482 | https://en.wikipedia.org/wiki/Locked%20On%20Podcast%20Network | The Locked On Podcast Network is a circle of more than 150 commercial sports podcasts produced in the United States providing daily news and commentary at the team and league level about American football, baseball, basketball, and ice hockey. The network also provides coverage of collegiate athletics for approximately 30 American institutions of higher learning.
Initially launched in 2016 by David Locke, radio play-by-play announcer for the Utah Jazz of the National Basketball Association, Locked On Sports was purchased in 2021 by Tegna, an offshoot of the Gannett newspaper group.
History
Origins
The Locked On Podcast Network — also commonly known as Locked On Sports — was established in June 2016 by David Locke, the radio voice of the Utah Jazz of the National Basketball Association. The network began as a single audio podcast, Locked On Jazz, the name of the show (and eventually the network) being an obvious play on the surname of the founder and host.
In a 2019 interview, Locke observed that after having been named play-by-play announcer of the Utah Jazz, he came to realize that "the job had changed" and that he could no longer simply call 82 games without fan interaction. He indicates that Locked On Jazz emerged as a vehicle to "create a relationship with the fan base, year-round, so that you’re talking to them on game day but also communicating with them on Twitter or Facebook."
The company established headquarters in Park City, Utah.
Development
Locked On Sports was largely a self-financed enterprise by founder David Locke, with only a single infusion of $750,000 of venture capital announced in 2019. Investors in the fledgling network included Bruce Gordon, formerly the chief financial officer of Disney Interactive Media Group, focused podcast investor Podfund, and Summit Capital, a Utah-based private equity firm.
The Locked On network grew to encompass podcasts targeted to fans of every individual team in the National Football League (NFL), National Basketball Association (NBA), National Hockey League (NHL), and Major League Baseball (MLB) as well as to the sports programs of more than 30 American universities.
Sale to Tegna
In January 2021 the Locked On Podcast Network was sold to communications giant Tegna, a digital and broadcasting spin-off of the Gannett newspaper group. Terms of the purchase were not disclosed at the time of sale.
Under terms of the sale, Locked On's CEO David Locke, COO Carl Weinstein, and four other full-time staff members were hired by Tegna. Locke remained president of the Locked on Podcast Network as of early 2022.
Move to YouTube
In May 2021 Locked On Sports expanded from audio to video podcasting when it launched its first YouTube channel. The move spurred growth of the network, with Tegna reporting a 48 percent gain in audience during 2021, for a total of 115 million podcast listens and views. During that year Locked On Sports produced about 700 podcast episodes per week.
Footnotes
External links
Locked On Podcast Network company website
Locked On Sports on Twitter
Matt Pacenza, "David Locke: The Voice of the Jazz (And Sports Fans Everywhere)," Salt Lake Magazine, September-October 2021.
New media
2016 podcast debuts
YouTube channels launched in 2021
Audio podcasts
Video podcasts
Interview podcasts
Talk show podcasts | Locked On Podcast Network | [
"Technology"
] | 656 | [
"Multimedia",
"New media"
] |
65,229,823 | https://en.wikipedia.org/wiki/GP%20%28nerve%20agent%29 | GP is an organophosphate nerve agent of the G-series, with a relatively slow rate of hydrolysis, and thus high stability and persistence in the environment.
References
G-series nerve agents
Acetylcholinesterase inhibitors
Methylphosphonofluoridates | GP (nerve agent) | [
"Chemistry"
] | 57 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
65,229,877 | https://en.wikipedia.org/wiki/EA-1356 | EA-1356 is an organophosphate nerve agent of the G-series. It is highly resistant to enzymatic degradation in the body. The nerve agent was tested at Edgewood Arsenal in Maryland (the "EA" in "EA-1356") among many other chemicals tested on humans. A novel enzyme was patented by the US Army in 2018 to break down EA-1356. It is a schedule 1 substance by the Chemical Weapons Convention standards. It is under the category of munitions of ML7.b.1.a.
References
G-series nerve agents
Acetylcholinesterase inhibitors
Methylphosphonofluoridates | EA-1356 | [
"Chemistry"
] | 135 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
65,230,548 | https://en.wikipedia.org/wiki/Dimethyl%28trifluoromethylthio%29arsine | Dimethyl(trifluoromethylthio)arsine is an arsenical compound developed by the United States military chemical weapon research program, which is described as "one of the most potent lung irritants known."
See also
Cacodyl
Cacodyl cyanide
Diphenylchlorarsine
Lewisite
Methyldichloroarsine
Tetrachlorodinitroethane
Bis(trifluoromethyl) disulfide
References
Arsenical vesicants
Arsenic(III) compounds
Vomiting agents
Trifluoromethylthio compounds
Cacodyl compounds | Dimethyl(trifluoromethylthio)arsine | [
"Chemistry"
] | 126 | [
"Chemical weapons",
"Organic compounds",
"Vomiting agents",
"Organic compound stubs",
"Organic chemistry stubs"
] |
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