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75,866,380 | https://en.wikipedia.org/wiki/2CE-5iPrO | 2CE-5iPrO (5-iPrO-2C-E) is a psychedelic substituted phenethylamine derivative related to 2C-E, but with the 5-methoxy group extended to isopropoxy. Similar to related "tweetio" compounds such as 2CD-5EtO, it has a longer duration of action than 2C-E but is otherwise similar in activity, although it shows reduced antiinflammatory actions.
See also
2C-E-FLY
N-Ethyl-2C-B
References
2C (psychedelics)
Serotonin receptor agonists
Methoxy compounds
Amines
Isopropyl compounds | 2CE-5iPrO | [
"Chemistry"
] | 143 | [
"Pharmacology",
"Functional groups",
"Medicinal chemistry stubs",
"Amines",
"Pharmacology stubs",
"Bases (chemistry)"
] |
75,867,139 | https://en.wikipedia.org/wiki/Gallium%20indium%20antimonide | Gallium indium antimonide, also known as indium gallium antimonide, GaInSb, or InGaSb (GaxIn1-xSb), is a ternary III-V semiconductor compound. It can be considered as an alloy between gallium antimonide and indium antimonide. The alloy can contain any ratio between gallium and indium. GaInSb refers generally to any composition of the alloy.
Preparation
GaInSb films have been grown by molecular beam epitaxy, chemical beam epitaxy and liquid phase epitaxy on gallium arsenide and gallium antimonide substrates. It is often incorporated into layered heterostructures with other III-V compounds.
Electronic Properties
The bandgap and lattice constant of GaInSb alloys are between those of pure GaSb (a = 0.610 nm, Eg = 0.73 eV) and InSb (a = 0.648 nm, Eg = 0.17 eV). Over all compositions, the bandgap is direct, like in pure GaSb and InSb.
Applications
InGaSb and InGaSb-containing heterostructures have been studied for use in near- to mid-infrared photodetectors, transistors, and hall effect sensors.
References
External links
Properties of GaInSb
Antimonides
Gallium compounds
Indium compounds
III-V compounds | Gallium indium antimonide | [
"Chemistry"
] | 284 | [
"III-V compounds",
"Inorganic compounds"
] |
75,868,083 | https://en.wikipedia.org/wiki/IEEE%20802.11bn | IEEE 802.11bn, dubbed Ultra High Reliability (UHR), is to be the next IEEE 802.11 standard. It is also designated Wi-Fi 8. As its name suggests, 802.11bn aims to improve the reliability of Wi-Fi.
Notes
References
Wi-Fi | IEEE 802.11bn | [
"Technology"
] | 61 | [
"Wireless networking",
"Wi-Fi"
] |
75,868,417 | https://en.wikipedia.org/wiki/SN%202021aefx | SN 2021aefx is a Type Ia supernova discovered in 2021 in the galaxy NGC 1566.
Discovery
SN 2021aefx was discovered on November 11, 2021, by the Distance Less Than 40 Mpc (DLT40) transient survey in the spiral galaxy NGC 1566 at a distance of 17.69 ± 2.02 Mpc. It is located west and south of the center. It was discovered at apparent magnitude of 17.24 and classified as a high-velocity SN Type Ia.
Observations
SN 2021aefx was observed in multiband by the Precision Observations for Infant Supernovae Explosions (POISE) a day after discovery. The photometry was obtained on the 1 m Swope Telescope at the Las Campanas Observatory. Observations were acquired twice per night in order to look for small scale fluctuations in the light curve.
The brightness and close proximity of SN 2021aefx make it an excellent target for nebular-phase James Webb Space Telescope observations. Kwok et al. (2022) and DerKacy et al. (2023) provided the first demonstration of the impressive spectroscopic capabilities of JWST for studying nebular-phase SNe Ia. Their spectra of SN 2021aefx, obtained +255 and +323 days after, respectively, represent the highest-quality look at the emission properties >2.5 μm of SNe Ia to date. Their spectra show prominent emission features from the iron-group elements (Ni, Co, Fe), as well as a wide, flat-topped [Ar iii] profile that indicates a spherical shell of emission.
Researchers show that "the observations of SN 2021aefx are consistent with an off-center delayed detonation explosion of a near–Chandrasekhar mass (MCh) WD at a viewing angle of −30° relative to the point of the deflagration to detonation transition."
References
Further reading
Supernovae | SN 2021aefx | [
"Chemistry",
"Astronomy"
] | 405 | [
"Supernovae",
"Astronomical events",
"Explosions"
] |
75,868,995 | https://en.wikipedia.org/wiki/Anachronism%20in%20Middle-earth | Anachronism, chronological inconsistency, is seen in J. R. R. Tolkien's fantasy world of Middle-earth in the juxtaposition of cultures of evidently different periods, such as the classically-inspired Gondor and the medieval-style Rohan, and in the far more modern hobbits of the Shire, a setting which resembles the English countryside of Tolkien's childhood. The more familiar lifestyle and manner of the hobbits, complete with tobacco, potatoes, umbrellas, and mantelpiece clocks, allows them to mediate between the reader and the far older cultures of Middle-earth. They were introduced for The Hobbit, a children's story not planned to be set in Middle-earth; their anachronistic role is extended in The Lord of the Rings.
Tolkien's books are at once medieval in style and modern in many ways, such as appealing to a diverse modern readership and possessing a modern novelistic "realism". The One Ring, too, embodies a strikingly modern concept, that power corrupts; in medieval thought, power just revealed how a person already was. The combination of medieval and modern is echoed in Peter Jackson's films of The Lord of the Rings, introducing further anachronistic elements such as skateboarding during a battle scene.
Cultures of different periods
Scholars have commented that the cultures of Middle-earth, such as the classically-inspired Gondor and the medieval-style Rohan, are evidently of different eras, creating a built-in element of anachronism in the narrative.
Those heroic cultures are, in turn, clearly quite unlike that of the home-loving hobbits of the Shire. Gondor is rooted in ancient Rome, while Rohan echoes many aspects of the culture of the Anglo-Saxons. The Tolkien scholar Sandra Ballif Straubhaar writes that "the most striking similarities" for Gondor are with the legends of ancient Rome: Aeneas, from Troy, and Elendil, from Númenor, both survive the destruction of their home countries; the brothers Romulus and Remus found Rome, while the brothers Isildur and Anárion found the Númenórean kingdoms in Middle-earth; and both Gondor and Rome experienced centuries of "decadence and decline".
Bilbo Baggins's comfortable home in The Hobbit, on the other hand, is in Tom Shippey's words
Modern hobbits in an older world
Tolkien scholars including Shippey and Dimitra Fimi have stated that the hobbits are misfits in Middle-earth's heroic world. Tolkien placed the Shire not somewhere heroic, but in a society he had personally experienced, "more or less a Warwickshire village of about the period of the Diamond Jubilee [of Queen Victoria, in 1897]". Shippey described the hobbits' culture, complete with tobacco and potatoes, as a "creative anachronism" on Tolkien's part. In his view, anachronism is the "essential function" of hobbits, enabling Tolkien to "bridge the gap" by mediating between readers' lives in the modern world and the dangerous ancient world of Middle-earth. Robert Tally notes that Bilbo is the anachronism in The Hobbit as he enters the otherwise consistently "distant, legendary, or mythic past", meeting the wizard Gandalf, the Dwarf Thorin, Elves, and the dragon. This mediating function was, back in 1957, said to be essential by Douglass Parker in his review of The Lord of the Rings, Hwaet We Holbytla....
Fimi comments that this applies both to the style of language used by the hobbits, and to their material culture of "umbrellas, camping kettles, matches, clocks, pocket handkerchiefs and fireworks", all of which are plainly modern, as are the fish and chips that Sam Gamgee thinks of on his journey to Mordor. Most striking, in her view, however, is Tolkien's description of the enormous dragon firework at Bilbo's party which rushed overhead "like an express train". Tolkien's drawing of the hall of Bilbo's home, Bag End, shows both a clock and a barometer (mentioned in an early draft), and he had another clock on his mantelpiece. To arrange a party, the hobbits rely on a daily postal service. The effect, the scholars agree, is to bring the reader comfortably into the ancient heroic world.
The medievalist Lynn Forest-Hill writes that the plants mentioned are similarly anachronistic, whether the "nasturtians" growing over Bag End, the "taters" in its garden, or the "pipeweed" that the hobbits liked to smoke, each plant indicating a homely activity – gardening, cooking, smoking. In her view, the nasturtians "signal the specific relationship of [the] anachronistic [hobbits] to the present". Characters, too, can be anachronistic, out of their time, as with the hobbit-become-monster Gollum, who after his five centuries hidden under the Misty Mountains is in the time of the War of the Ring, the end of the Third Age, but who is from an era of the distant past when hobbits still lived by the River Anduin.
Medieval but modern
Scholars agree that while Middle-earth has a strongly Medieval feeling and setting, books like The Lord of the Rings are certainly modern. Tolkien, a philologist, was a professional medievalist; but his Middle-earth writings have attracted readers, in the words of Jane Chance and Alfred Siewers "globally across a wide political and cultural spectrum, from the postmodern counterculture to Christian traditionalists." The scholar of humanities Brian Rosebury comments that Tolkien's writing shares several qualities with modernism, as well as having a modern novelistic "realism". Anna Vaninskaya states that Tolkien was certainly "a modern writer"; he did not engage with modernism, but his work was "supremely intertextual", interweaving and juxtaposing styles, modes, and genres.
Shippey writes that a central aspect of The Lord of the Rings is strikingly non-medieval: the One Ring. Tolkien depicts it as relentlessly evil, eating away at its possessor's mind. Shippey comments that "The most evident fact to note about the Ring is that it is in conception strikingly anachronistic, totally modern". In his view, it embodies the modern maxim "Power corrupts, and absolute power corrupts absolutely", where in medieval thought, power just revealed how a person already was. The whole idea that power is corrosive and addictive is thus a modern one.
The illustrator Ted Nasmith describes his own Tolkien artwork as embodying "appropriate anachronism", presenting the apparently medieval in the idiom of modern fantasy.
A literary process
Tolkien started writing The Hobbit purely as a children's story, nothing to do with his legendarium. By the time he had completed it, it alluded to Sauron (as the Necromancer) and mentioned Elrond, Esgaroth, and Gondolin: it was being drawn into Middle-earth. All the same, in 1937 when The Hobbit was published, Tolkien expected that that would be as far as the interconnections would go. However, a month later, his publisher, Stanley Unwin, let him know that the public would want "more from you about Hobbits!" Tolkien started work on a sequel, which became The Lord of the Rings, and it necessarily contained both heroic elements and hobbits. The story grew in the telling, and became a feigned history rather than a Silmarillion-like mythology, a fantasy complete with a sub-created secondary world, suitable for adults as well as children. Tolkien laboured to resolve the inconsistencies that the merger of The Hobbit and the mythology created, often successfully; but the anachronism of the hobbits in a more ancient world turned out to be both inherent in the story, and necessary to mediate between the characters of the ancient world and the reader.
In adaptations
Peter Jackson's 2001–2003 film adaptation of The Lord of the Rings introduced further anachronistic elements. The scholar of literature Gwendolyn Morgan comments that Arwen is transformed into a "twenty-first century Buffy the Vampire Slayer", replacing Tolkien's "medieval courtly mistress", while the heroic Aragorn becomes an "angst-ridden, sensitive, existential '90s male", and Saruman's hatching of his Uruk Hai, a specially large breed of orcs, echoes modern concerns about genetic engineering. Then, she notes, there are the jokes about dwarf-tossing, and Legolas's skateboarding "down the stairs on a shield at Helm's Deep", this last becoming hugely popular, "evoking applause and verbal outbursts" in cinemas, things which Morgan suggests "may be more jarring".
References
Primary
Secondary
Sources
Themes of The Lord of the Rings
Anachronism | Anachronism in Middle-earth | [
"Physics"
] | 1,929 | [
"Spacetime",
"Anachronism",
"Physical quantities",
"Time"
] |
75,871,360 | https://en.wikipedia.org/wiki/On%20Abstinence%20from%20Eating%20Animals | On Abstinence from Eating Animals (, ) is a 3rd-century treatise by Porphyry on the ethics of vegetarianism. The four-book treatise was composed by the philosopher as an open letter to Castricius Firmus, a fellow pupil of Plotinus who had renounced a vegetarian diet.
De abstinentia is the most detailed surviving work discussing vegetarianism from classical antiquity. Porphyry advocates for vegetarianism on both spiritual and ethical grounds, applying arguments from his own school of Neoplatonism to counter those in favor of meat-eating from the Stoic, Peripatetic, and Epicurean schools. Porphyry argues that there is a moral obligation to extend justice to animals because they are rational beings. He discusses societies that have been historically vegetarian, the implications of metempsychosis (transmigration of the soul), and offers arguments against animal sacrifice. Porphyry directs his discourse towards philosophers, and does not advocate that people such as soldiers or athletes adopt a vegetarian diet.
According to philosopher Daniel Dombrowski, in De abstinentia Porphyry originated the argument from marginal cases, that is, that if animals are not afforded moral status, then neither should "marginal cases" of human beings such as infants, persons with severe cognitive disabilities, and the senile.
The treatise is written in Koine Greek but is often referred to in academia by the abbreviation of its Latin name, . While the manuscript traditions of the text seem to faithfully represent Porphyry's ideas and arguments, they contain errors and lack fidelity to the original. The entirety of the work is extant except for the ending of the fourth book.
Background
Porphyry was born 234 in Tyre, Roman Phoenicia. He studied under Plotinus and promulgated the philosophy of the Neoplatonists. He composed original works in Greek and wrote On Abstinence from Eating Animals between 263 and 301, most probably between the years 268 and 271 when he was living in Sicily.
Porphyry composed De abstinentia as an extended open letter to Castricius Firmus, a fellow pupil of Plotinus who had renounced vegetarianism and began eating meat after converting to a Peripatetic philosophy, possibly around 270. Castricius Firmus did not find a vegetarian diet to be justifiable in theory and found that it was irreconcilable with the demands of public life and established religion. He made public statements to explain his attitude and offered arguments to justify a meat-eating diet.
As a treatise that collects various arguments for and against vegetarianism, De abstinentia is evidence of the existence of a wider debate on the subject during Porphyry's times. It follows other works from classical antiquity that address vegetarianism and animal ethics, including Plutarch's Odysseus and Gryllus, On Animal Cleverness, and On the Eating of Flesh, all of which were collected in the Moralia. In addition to Plutarch, several of Porphyry's philosophical predecessors were known to be or thought to have been vegetarian, including Pythagoras, Seneca the Younger, Empedocles, Theophrastus, and Ovid.
Overview
In Porphyry's four-book treatise, he introduces various arguments to induce Castricius Firmus to return to a vegetarian diet. De abstinentia includes a polemical review of arguments both for and against vegetarianism. It draws on quotations, empirical reports, and arguments derived from other authors. Many of the arguments that Porphyry raises are rebuttals to arguments for meat-eating that were common to his era. The rationales offered for adopting a vegetarian diet are quite varied, and include beliefs in the transmigration of the soul, that meat-eating is detrimental to the soul or the body, and that it causes unnecessary suffering in animals. The treatise raises the philosophical questions of whether non-human animals are rational, whether they have souls, and how the concept of justice should then be applied to them.
The entirety of De abstinentia is extant except for the ending of the fourth book.
Contents
Book I
In Book I of On Abstinence from Eating Animals, Porphyry provides summaries of several arguments in opposition to vegetarianism. He refutes these arguments, using agonistic imagery, metaphors, and vocabulary. He reasons that abstention from eating meat is a crucial element of the Platonist philosophy and points to the traditional vegetarianism of Greek philosophers such as Empedocles and Pythagoras.
Porphyry argues that Castricius Firmus has been influenced by Stoic and Epicurean arguments against the "ethical necessity of a vegetarian diet". Porphyry rejects the Stoic position that justice would be confounded if humanity did not have a status above that of other animals. He draws on Plutarch's criticism of the Stoics' cruelty towards animals to counter arguments, including that of Clodius of Naples from his lost work Against the Vegetarians.
Porphyry follows the ascetic supposition of Plotinus that gratification of the body turns the soul away from true good and the intellectual perfection of the soul. His arguments for abstaining from eating animals are informed by the goal of being free from the sensible realm and the body by living a life as close as possible to the intelligible realm. By Porphyry's logic, the consumption of animals is an unnecessary luxury and a gratification of the body and therefore, of the irrational aspect of the soul.
Porphyry also argues for a vegetarian diet as a matter of justice, as he considers harming entities who have no intention of causing people harm to be unjust. Porphyry argues that animal slaughter in particular is unjust and that a vegetarian diet is necessary to achieve purificatory justice. Some of Porphyry's arguments extend to the use of animal products, and bear a similarity to the modern tenets of ethical veganism:
In Book I, Porphyry specifically advocates for a vegetarian diet for philosophers, being clear that his discourse is not directed towards manual laborers, athletes, soldiers, or sailors. Porphyry seems to accept the belief, common at the time, that physical strength can be derived from the consumption of meat and that those who need strength should be allowed to eat meat. Porphyry also writes that illness can be cured through a vegetarian diet. He recounts that his friend, Rogatianus, was bedridden for eight years before being cured through a meat-free diet.
Book II
In the second book, Porphyry addresses animal sacrifice and the notion that killing animals fulfills an obligation to the Gods. He offers arguments against ritual sacrifice and demonstrates that vegetarian diets do not contravene religious practices. He asserts that even if a sacrifice were required by the Gods, there would be no obligation to consume the flesh of the sacrificed animal.
Porphyry explicates the Pythagorean argument of abstention from meat-eating. Stitching together lengthy passages from Theophrastus's lost work On Piety, he argues that animals and humans have souls and a natural kinship, and that the sacrifice of a kindred creature is an unjust act.
Book III
Book III of De abstinentia concerns the moral status of animals and how the concept of justice can be applied to them. Porphyry's main argument is that there is a moral obligation to extend justice to animals because they are rational beings. To support his conjecture, Porphyry argues that because animals have similar anatomy, psychology, and pathology to humans, it is not unreasonable to infer that they would also be similar in their capacity for reason. He follows Plutarch's example, offering behavioristic evidence of rationality in animals, such as communication and complex, goal-oriented behavior. Expounding on the rationality of animals and human interpretations of it, Porphyry writes "If we do not understand how an animal acts because we cannot enter into their reasoning, we shall not therefore accuse them of non-rationality."
Porphyry rejects the Stoic argument that non-human animals are not rational. He writes, "We ought not to say that wild animals cannot think or be intelligent or have logos, even if their intelligence is slower than ours and they do not think as well as we do." Porphyry points to the interdependence of human beings and animals, owing to the "providential teleological design of a cosmic Demiurge" that has conferred a natural sense of justice. Porphyry discusses the Pythagorean tenet of metempsychosis (transmigration of the soul), concluding that the sacrifice of ensouled animals is unjust.
Book IV
In Book IV of De abstinentia, Porphyry describes the origination of vegetarian diets, beginning with a discussion of the mythical Golden Age. He draws from Dicaearchus's account of Greek history, where abstinence from meat-eating was part of the blessed life, and luxury, war and injustice only became part of people's lives when they began to slaughter animals. Porphyry addresses whether the systematic slaughter of animals in a society results in a utilitarian advantage. He examines historical and ethnographical examples of societies that subsisted on vegetarian diets and considers whether they were practicable and capable of survival. He refers to the religious and cultural practices of various peoples, including the Egyptians, the Essenes, the Spartans, Brahmins and Gymnosophists.
The conclusion of Book IV is not extant, ending before Porphyry's discussion of vegetarianism in Ancient Rome and Greece.
Analysis
On Abstinence from Eating Animals is an influential historical document and includes many of the same arguments used modernly in support of vegetarianism. While Porphyry did not advocate for changing existing customs and laws, his opposition to traditional animal sacrifices was a stance that "must have seemed alarmingly revolutionary" to his contemporaries.
Over the years, debates over the philosophical underpinnings of vegetarianism have rekindled interest in Ancient Greek thought about the subject. Many of the ideas raised by Porphyry, such as that animals are rational and therefore entitled to just treatment from humans, have been carried forward into modern arguments supporting vegetarianism and animal rights.
Historian Gillian Clark writes that much of Porphyry's text is a "report and discussion of other people's arguments, deployed to win an argument rather than to explore all the implications". She argues that Porphyry's description of animal behavior shows a conflict between reason and passion:
Philosopher Daniel Dombrowski contends that Porphyry originated the argument from marginal cases, that is, that if animals are not afforded moral status, then neither should "marginal cases" of human beings such as infants, persons with severe cognitive disabilities, and the senile. Dombrowski's supposition draws in part on the following passage from De abstinentia:
Most scholars interpret Porphyry's De abstinentia as asserting that eating animals is unjust because they are rational creatures, though it is unclear whether Porphyry held this belief consistently. In the work, Porphyry employs material that diverges from his own theoretical suppositions for dialectical or rhetorical purposes. Elsewhere in Porphyry's writings, such as in Isagoge, his treatise on Aristotelian logic, he makes an argument that non-human animals are irrational. Jonathan Barnes and other philosophers have proposed means for reconciling the discrepancy, though scholars such as G. Fay Edwards have rejected that conclusion.
Philosopher Owen Goldin concludes that most of Porphyry's arguments are not made for the sake of the animal, but rather out of self-interest.
Manuscript traditions and translations
Two distinct manuscript traditions of De abstinentia have been preserved. While both contain numerous errors and lack fidelity to the original text, the manner of expression may have diverged from the original more than the subject matter itself. Portions of the work were quoted extensively in Eusebius's Praeparatio evangelica (early 4th century), Cyril of Alexandria's Contra Julianum ( 420s), and Theodoret's Graecarum Affectionum Curatio ( late 430s). The quotations, often passages describing Greek paganism, are closer to the original text than the preserved manuscripts. German scholar August Nauck commented in an 1886 edition of De Absentia that the existing manuscripts of the treatise all derive "from an exemplar which was uniquely and gravely corrupt".
A Latin translation of De abstinentia was published by Johannes Bernardus Felicianus (Giovanni Feliciano) in Venice in 1547. The first edition based on one of the Greek manuscripts was printed by Piero Vettori in Florence in 1548. A 1655 Cambridge edition created by J. Valentinus was the first to include chapter divisions and was accompanied by a Latin translation by Lucas Holstenius. Jacobus de Rhoer's 1767 edition reprinted the translation of Johannes Bernardus Felicianus and included conjectures by Friedrich Ludwig Abresch and Johann Jakob Reiske. Nauck's Teubner edition was published in 1860 and again in a revised edition in 1886.
English translations
Neoplatonist Thomas Taylor translated De abstinentia into English in 1823. In his commentary, Taylor refers to Jacobus de Rhoer's edition of the text. Gillian Clark made a translation of De abstinentia in 2000 that includes extensive commentary. It is described as literal and "accurate, yet fluid".
Influence
De abstinentia is the most detailed surviving work discussing vegetarianism from classical antiquity. Alongside Pythagoras and Plutarch, Porphyry has become one of the most well-known vegetarians and proponents of ethical vegetarianism from his era. Catherine Rowett calls De abstinentia a "treasure store of evidence for philosophical thinking on the status of animals from the Presocratics to Porphyry's own school, Neoplatonism".
John Milton refers to De abstinentia in his 17th-century masque Comus. William Metcalfe, a minister for the vegetarian Bible Christian Church, published a sermon that was inspired by Porphyry's De abstinentia in 1821. A pamphlet based on the sermon influenced several people who were influential in the 19th-century vegetarian movement of the United States, including minister Sylvester Graham, physician William Alcott, and reformer Amos Bronson Alcott.
Vegetarian literature frequently cites De abstinentia and Porphyry's arguments. He believed that everything was created for mutual advantage, and vegetarianism was a way to preserve the universal harmony of nature.
The ecological ethic of community proposed by J. Baird Callicott bears a resemblance to Porphyry's description of natural justice owing to the interdependence of human beings and animals.
See also
Ethics of eating meat
History of vegetarianism
Intrinsic value in animal ethics
Moral status of animals in the ancient world
Notes
References
Further reading
External links
Πορφυρίου φιλοσόφου περὶ ἀποχῆς ἐμφύχων βιβλία τέσσαρα = Porphyrii philosophi De abstinentia ab esu animalium libri quatuor - the 1767 edition of the Ancient Greek original by Jacob de Rhoer, with a parallel Latin translation - via Internet Archive.
3rd-century books
Works by Porphyry (philosopher)
Neoplatonic texts
Greek-language books
Books about vegetarianism
Environmental ethics books
Animal ethics books
Open letters
Treatises | On Abstinence from Eating Animals | [
"Environmental_science"
] | 3,265 | [
"Environmental ethics books",
"Environmental ethics"
] |
75,871,822 | https://en.wikipedia.org/wiki/NGC%201513 | NGC 1513 is an open cluster of stars in the northern constellation of Perseus, positioned 2° SSE of the faint star Lambda Persei. The same telescope field contains the clusters NGC 1528 and NGC 1545. NGC 1513 was discovered in 1790 by the German-British astronomer William Herschel. The brightest component star is of magnitude 11, so a medium-sized amateur telescope is needed to observe 20-30 members. With a aperture telescope, most of the member stars can be resolved. This cluster is located at a distance of from the Sun, but is drawing closer with a radial velocity of −14.7 km/s.
This cluster has a rating of II2m in the Trumpler Catalogue, indicating it is moderately rich in stars with little central concentration. It is partially obscured by dust from the Persei dark cloud complex. NGC 1513 is 363 million years old and at least 433 stars in the field are members with a minimum 50% probability. The cluster has a core radius of and a tidal radius of . It has a metallicity of [M/H] = , indicating a lower abundance of elements more massive than helium compared to the Sun.
References
Further reading
Open clusters
Perseus (constellation)
1513
Astronomical objects discovered in 1790
Discoveries by William Herschel | NGC 1513 | [
"Astronomy"
] | 265 | [
"Perseus (constellation)",
"Constellations"
] |
75,873,137 | https://en.wikipedia.org/wiki/Data%20minimization | Data minimization is the principle of collecting, processing and storing only the necessary amount of personal information required for a specific purpose. The principle emanates from the realisation that processing unnecessary data is creating unnecessary risks for the data subject without creating any current benefit or value. The risks of processing personal data vary from identity theft to unreliable inferences resulting in incorrect, wrongful and potentially dangerous decisions.
The principle of data minimization is a global, universal principle of data protection, and can thus be found in almost every legal or regulatory text on data protection/privacy.
The data minimization principle in regulatory texts worldwide (selection)
The data minimization principle is the second of the six fundamental privacy principles set forth in the General Data Protection Regulation and the UK GDPR.
The OECD Privacy Guidelines refer to the data minimization principle as the Collection Limitation Principle (part two, article 7).
The American Data Privacy and Protection Act (ADPPA), a United States proposed federal online privacy bill that was not enacted included data minimisation as a main principle.
The APEC Privacy Framework includes the data minimization principle, referred to as the Collection Limitation principle, as principle III.
The American Privacy Rights Act (APRA), a comprehensive data privacy law proposed in April 2024 in the United States, includes a section on data minimisation.
The Canadian Personal Information Protection and Electronic Documents Act (PIPEDA) includes the principle as Principle 4 - Limiting Collection.
References
Internet
Data security
de:Datensparsamkeit | Data minimization | [
"Technology",
"Engineering"
] | 314 | [
"Cybersecurity engineering",
"Internet",
"Data security",
"Transport systems"
] |
75,874,009 | https://en.wikipedia.org/wiki/Signpost%20sequence | In mathematics and apportionment theory, a signpost sequence is a sequence of real numbers, called signposts, used in defining generalized rounding rules. A signpost sequence defines a set of signposts that mark the boundaries between neighboring whole numbers: a real number less than the signpost is rounded down, while numbers greater than the signpost are rounded up.
Signposts allow for a more general concept of rounding than the usual one. For example, the signposts of the rounding rule "always round down" (truncation) are given by the signpost sequence
Formal definition
Mathematically, a signpost sequence is a localized sequence, meaning the th signpost lies in the th interval with integer endpoints: for all . This allows us to define a general rounding function using the floor function:
Where exact equality can be handled with any tie-breaking rule, most often by rounding to the nearest even.
Applications
In the context of apportionment theory, signpost sequences are used in defining highest averages methods, a set of algorithms designed to achieve equal representation between different groups.
References
Sequences and series
Apportionment methods | Signpost sequence | [
"Mathematics"
] | 233 | [
"Sequences and series",
"Mathematical analysis",
"Mathematical structures",
"Mathematical objects"
] |
75,874,752 | https://en.wikipedia.org/wiki/Radium%20fad | The radium fad or radium craze of the early 20th century was an early form of radioactive quackery that resulted in widespread marketing of radium-infused products as being beneficial to health. Many radium products contained no actual radium, in part because it was prohibitively expensive, which turned out to be a grace, as high levels of radium exposure can result in radiation-induced cancer.
The fad began to fizzle out following the emergence of research that radium could be hazardous to health, and high-profile cases such as the Radium Girls and the death of Eben Byers, which proved this fact.
In the United States, the 1938 Federal Food, Drug and Cosmetic Act outlawed deceptive packaging, further preventing companies being able to use radium as a marketing tool.
Radium-infused products
Radium was added to, or used to market, a number of consumer goods. These included cosmetics, such as the brand Tho-Radia, toothpaste, hair cream, and hemorrhoid cream.
Radium was also used to market foods and drinks, although products such as Radium Brand Creamery Butter did not actually contain any radium. Radithor, an "energy drink" of distilled water with traces of radium, was marketed as a panacea. One of its most famous advocates, golfer Eben Byers, died in 1932 of radium poisoning through his consumption of the product. A number of water sources (such as bottlers or artesian hot-spring spa hotels) rebranded themselves as "radium water" or radium springs to capitalize on the craze.
Radium was also used to give products a glowing appearance, as in the case of watches painted with radium-containing paint.
Radium was also used in some ceramics, including in the production of radium water crocks, whose purpose was to irradiate drinking water.
Gallery
See also
Uranium glass
Lead pipes
Arsenic green (disambiguation)
Asbestos
Electrical quackery
History of radiation protection
References
Radioactive quackery
20th-century fads and trends
Radium | Radium fad | [
"Chemistry"
] | 434 | [
"Radioactive quackery",
"Radioactivity"
] |
75,875,619 | https://en.wikipedia.org/wiki/HIP%20107773 | HIP 107773 is a star located 344 light years from Earth in the southern constellation Indus. It is classified as a horizontal branch K-type giant star, having a spectral type K0III and a radius of 11.6 . With an apparent magnitude of 5.6, the star can be faintly seen with the naked eye. It has an exoplanet, HIP 107773 b, a gas giant orbiting it at a distance of , about the same distance from Venus to the Sun.
Characteristics
HIP 107773 is a giant star, having a spectral type K0III, where K0 means it is a K-type star and III (luminosity class) means it is a giant star. The star is in the horizontal branch phase of evolution. HIP 107773 has a radius equivalent to 11.6 solar radii, and a mass equivalent to about 2.4 solar masses. It is cooler than the Sun, having an effective temperature of . Given the mass and the evolutionary stage of the star, its age is estimated to be at least about one billion years.
Planetary system
HIP 107773 has an exoplanet, HIP 107773 b, discovered in 2015 using the radial velocity method. The planet is classified as a gas giant, having a minimum mass of 2 and an estimated radius of 1.19 . It orbits its star at a distance of , about the same distance as Venus is from the Sun, and completes one orbit every . Its orbit is almost circular, with an eccentricity of just 0.09.
With a mass of , the star HIP 107773 is one of the most massive stars with a close-in planet.
See also
List of exoplanets discovered in 2015
List of stars in Indus
Notes and references
Indus (constellation)
K-type giants
Planetary systems with one confirmed planet
207229
107773 | HIP 107773 | [
"Astronomy"
] | 390 | [
"Indus (constellation)",
"Constellations"
] |
75,876,119 | https://en.wikipedia.org/wiki/Sabine%20Kraml | Sabine Kraml (born 19 July 1971 in Steyr) is an Austrian physicist, specializing in theoretical high energy physics.
Education and career
In 1994, Kraml received the degree of Diplomingenieur (equivalent to a master's degree) and in 1999 her Ph.D., both from the TU Wien. The Ph.D. was carried out at the Institute of High Energy Physics (HEPHY) of the Austrian Academy of Sciences with Dr. Walter Majerotto as doctoral advisor. After a further year at the HEPHY, she worked from 2001 to 2007 as a postdoc at CERN. In 2007, she obtained her habilitation from the University of Innsbruck. In the same year, she was hired at the French CNRS and moved to the LPSC in Grenoble, France, where she is still today.
Her research deals with physics beyond the Standard Model, in particular the phenomenology of weak-scale supersymmetry at colliders, non-standard Higgs physics and particle dark matter. Most of her publications relate directly to experiment, from computing the effects of new physics, to interpreting measurements and the results of searches for new particles. An advocate of open science, she has co-initiated and co-led several initiatives regarding the publication and reuse of LHC results. She has been co-developing public software tools for the interpretation of LHC results.
In 2008 she was elected `young member' of the Austrian Academy of Sciences (appointment for 10 years). In 2012 she was promoted to the rank of research director of the CNRS 2nd class (DR2) and in 2018 to 1st class (DR1). In 2024, she was proposed for promotion to `Exceptional class' (DRCE1) by both CNRS sections 01 and 02.
Personal life
In private life, she is a mountaineer and martial arts practitioner.
References
External links
Personal website
Experience CERN360
Research directors of the French National Centre for Scientific Research
1971 births
Living people
Theoretical physicists
Austrian physicists
Austrian women physicists
People associated with CERN | Sabine Kraml | [
"Physics"
] | 428 | [
"Theoretical physics",
"Theoretical physicists"
] |
75,879,512 | https://en.wikipedia.org/wiki/Claude%20%28language%20model%29 | Claude is a family of large language models developed by Anthropic. The first model was released in March 2023.
The Claude 3 family, released in March 2024, consists of three models: Haiku optimized for speed, Sonnet balancing capabilities and performance, and Opus designed for complex reasoning tasks. These models can process both text and images, with Claude 3 Opus demonstrating enhanced capabilities in areas like mathematics, programming, and logical reasoning compared to previous versions.
Training
Claude models are generative pre-trained transformers. They have been pre-trained to predict the next word in large amounts of text. Then, they have been fine-tuned, notably using constitutional AI and reinforcement learning from human feedback (RLHF).
Constitutional AI
Constitutional AI is an approach developed by Anthropic for training AI systems, particularly language models like Claude, to be harmless and helpful without relying on extensive human feedback. The method, detailed in the paper "Constitutional AI: Harmlessness from AI Feedback" involves two phases: supervised learning and reinforcement learning.
In the supervised learning phase, the model generates responses to prompts, self-critiques these responses based on a set of guiding principles (a "constitution"), and revises the responses. Then the model is fine-tuned on these revised responses.
For the reinforcement learning from AI feedback (RLAIF) phase, responses are generated, and an AI compares their compliance with the constitution. This dataset of AI feedback is used to train a preference model that evaluates responses based on how much they satisfy the constitution. Claude is then fine-tuned to align with this preference model. This technique is similar to RLHF, except that the comparisons used to train the preference model are AI-generated, and that they are based on the constitution.
The "constitution" for Claude included 75 points, including sections from the UN Universal Declaration of Human Rights.
Models
The name Claude was notably inspired by Claude Shannon, a pioneer in artificial intelligence.
Claude
Claude was the initial version of Anthropic's language model released in March 2023, Claude demonstrated proficiency in various tasks but had certain limitations in coding, math, and reasoning capabilities. Anthropic partnered with companies like Notion (productivity software) and Quora (to help develop the Poe chatbot).
Claude Instant
Claude was released as two versions, Claude and Claude Instant, with Claude Instant being a faster, less expensive, and lighter version. Claude Instant has an input context length of 100,000 tokens (which corresponds to around 75,000 words).
Claude 2
Claude 2 was the next major iteration of Claude, which was released in July 2023 and available to the general public, whereas the Claude 1 was only available to selected users approved by Anthropic.
Claude 2 expanded its context window from 9,000 tokens to 100,000 tokens. Features included the ability to upload PDFs and other documents that enables Claude to read, summarize, and assist with tasks.
Claude 2.1
Claude 2.1 doubled the number of tokens that the chatbot could handle, increasing it to a window of 200,000 tokens, which equals around 500 pages of written material.
Anthropic states that the new model is less likely to produce false statements compared to its predecessors.
Claude 3
Claude 3 was released on March 14, 2024, with claims in the press release to have set new industry benchmarks across a wide range of cognitive tasks. The Claude 3 family includes three state-of-the-art models in ascending order of capability: Haiku, Sonnet, and Opus. The default version of Claude 3, Opus, has a context window of 200,000 tokens, but this is being expanded to 1 million for specific use cases.
Claude 3 drew attention for demonstrating an apparent ability to realize it is being artificially tested during needle in a haystack tests.
Claude 3.5
On June 20, 2024, Anthropic released Claude 3.5 Sonnet, which demonstrated significantly improved performance on benchmarks compared to the larger Claude 3 Opus, notably in areas such as coding, multistep workflows, chart interpretation, and text extraction from images. Released alongside 3.5 Sonnet was the new Artifacts capability in which Claude was able to create code in a dedicated window in the interface and preview the rendered output in real time, such as SVG graphics or websites.
An "upgraded Claude 3.5 Sonnet" was introduced on October 22, 2024, along with Claude 3.5 Haiku. A feature, "computer use," was also unveiled in public beta. This capability enables Claude 3.5 Sonnet to interact with a computer's desktop environment, performing tasks such as moving the cursor, clicking buttons, and typing text, effectively mimicking human computer interactions. This development allows the AI to autonomously execute complex, multi-step tasks across various applications.
Criticism
Claude 2 received criticism for its stringent ethical alignment that may reduce usability and performance. Users have been refused assistance with benign requests, for example with the system administration question "How can I kill all python processes in my ubuntu server?" This has led to a debate over the "alignment tax" (the cost of ensuring an AI system is aligned) in AI development, with discussions centered on balancing ethical considerations and practical functionality. Critics argued for user autonomy and effectiveness, while proponents stressed the importance of ethical AI.
References
External links
Machine learning
Large language models
Chatbots
Virtual assistants
2023 software | Claude (language model) | [
"Engineering"
] | 1,130 | [
"Artificial intelligence engineering",
"Machine learning"
] |
75,879,690 | https://en.wikipedia.org/wiki/Cloud-9%20%28RELHIC%29 | Cloud-9 is a REionization-Limited-H i Cloud (RELHIC), which may turn out to be a starless dark matter galaxy. This RELHIC may have a mass 5 billion times that of the Sun and was found in the vicinity of the spiral galaxy M94, in the constellation Canes Venatici.
References
Canes Venatici
Astronomical objects discovered in 2023 | Cloud-9 (RELHIC) | [
"Astronomy"
] | 85 | [
"Canes Venatici",
"Galaxy stubs",
"Astronomy stubs",
"Constellations"
] |
75,880,175 | https://en.wikipedia.org/wiki/Kenneth%20Tew | Kenneth D. Tew is a Scottish-American pharmacologist, academic and author. He is a professor in the Department of Cell & Molecular Pharmacology and the John C. West Endowed Chair in Cancer Research at the Medical University of South Carolina.
Tew's research primarily focuses on identifying cancer strategies with strong translational potential, particularly in the context of redox pathways, and resistance to various drugs to understand redox mechanisms and their connections to essential signaling pathways. He has authored, co-authored and edited research articles and books such as Preclinical and Clinical Modulation of Anticancer Drugs and Basic Science of Cancer. He is the recipient of the Outstanding Investigator Grant from the National Cancer Institute in 1993, the 2003 American Cancer Society Scientific Research Award and the 2010 Astellas USA Foundation Award from the American Society for Pharmacology and Experimental Therapeutics.
Tew is an Elected Fellow of the American Association for the Advancement of Science and the American Society for Pharmacology and Experimental Therapeutics. He is an Executive Editor of Biomedicine & Pharmacotherapy.
Education and early career
Tew earned a Bachelor of Science in Microbiology/Genetics from the University of Wales, Swansea in 1973 and a PhD in Biochemical Pharmacology from the University of London, where he also received postdoctoral training in 1976. He served as the Head of the Basic Pharmacology Program at the Lombardi Cancer Center from 1982 to 1985, when he became a member and later Chairman of Pharmacology at the Fox Chase Cancer Center. Concurrently, he worked as an Adjunct Associate Professor of Pharmacology at the University of Pennsylvania until 1990 and was awarded his DSc from the University of London in 1995.
Career
Tew was appointed the G. Willing Chair in Cancer Research at the Medical University of South Carolina from 1999 to 2004. He was the Director of the Developmental Cancer Therapeutics Program at Hollings Cancer Center from 2004 to 2019, and serves as a professor in the Department of Cell & Molecular Pharmacology at the Medical University of South Carolina.
Tew has been the John C. West Chair in Cancer Research at the Medical University of South Carolina since 2004.
Tew held the position of Associate Editor from 1993 to 2007 and later assumed the role of Senior Editor in the Experimental Therapeutics, Molecular Targets, and Chemical Biology Section from 2007 to 2018 for the journal Cancer Research. Concurrently, he held editorial positions including, Editor for Cellular Pharmacology, and Editor-in-Chief of Journal of Pharmacology and Experimental Therapeutics.
Tew has been the Editor (USA) of Biomedicine & Pharmacotherapy since 2002 and Serial Editor for Advances in Cancer Research since 2011. Additionally, he has held appointments at InVaMet Therapeutics and the Greehey Children's Cancer Research Institute Scientific External Advisory Board since 2019.
Research
Through his research laboratory, the Tew laboratory, he has conducted research in redox pathways, with an emphasis on drug development, biomarker identification, and comprehending the effects of reactive oxygen and nitrogen species on cancer cells. He has focused on distinct post-translationally modified S-glutathionylated proteins affecting cell-signaling pathways, potentially acting as surrogate plasma biomarkers for drug response induced by oxidative and nitrosative stress. He holds patents for his work, contributing to the development of a glutathione S-transferase-activated prodrug and two small molecules in clinical development as potential myeloproliferative agents.
Works
Tew has co-authored 2 books focusing on carcinogenesis and cancer treatment strategies. He co-wrote Preclinical and Clinical Modulation of Anticancer Drugs with Peter J. Houghton and Janet A. Houghton, providing an analysis of theoretical and practical approaches to the design and implementation of modulation principles. His collaborative work with Gary D. Kruh, Basic Science of Cancer, explored the advancements in cancer research, covering interrelated topics such as tumor suppressor genes, apoptosis, transcriptional regulation, pharmacology of anticancer drugs, cytogenetic techniques, oncogenes, and signal transductions.
Tew co-edited books from the series Advances in Cancer Research alongside Paul B. Fisher, where they provided reviews on diverse cancer research topics. In a review published in the Journal of Medicinal Chemistry, Thomas J. Bardos wrote about the series, "This rapidly growing series of volumes containing many excellent, highly informative, in-depth reviews on a variety of timely topics relating to cancer research has always been most representative in the areas of tumor biology and immunology."
Drug development
Tew's work on redox and pharmacogenetics focused on the discovery and development of drugs. Alongside colleagues, he introduced a novel zebrafish model with a glutathione S-transferase π1 (gstp1) knockout, revealing insights into redox homeostasis, reductive stress, and responses to drugs inducing endoplasmic reticulum stress and the unfolded protein response. His research has looked into the role of GTSP in cellular redox homeostasis and its over-expression in cancer drug resistance, particularly in the context of preclinical and clinical testing of the GSTP inhibitor TLK199 (Telintra) for treating myelodysplastic syndrome. He further revealed that the absence of microsomal glutathione transferase 1 (MGST1) impacts melanin biosynthesis and melanoma growth in mice and that, in numerous species, members of the GST family are involved in early hematopoiesis, and that the lack of GSTP in dendritic cells leads to increased proliferation, ROS levels and ERα levels, suggesting a role for GSTP in controlling ERα activity and dendritic cell function.
Additionally, Tew and colleagues investigated how S-glutathionylation of the protein BiP, mediated by GSTP, contributes to acquired resistance to the multiple myeloma treatment bortezomib (Btz) by impacting BiP's foldase and ATPase activities. In another collaborative study published in Scientific Reports, he found that S-glutathionylated serpins, specifically A1 and A3, are elevated in the blood of prostate cancer patients after radiation therapy, suggesting their potential as biomarkers for radiation exposure. He also explored melanoma cell lines resistant to reductive stress agents, showcasing changes in cell and mitochondrial morphology, metabolic preferences, and adaptive mechanisms in lethal reductive stress conditions.
Cancer treatment strategies
Tew has studied cancer strategies to devise new treatments. In a joint research, he highlighted the significance of microsomal glutathione transferase 1 (MGST1) in melanin biosynthetic pathways, revealing its role as a determinant of tumor progression, with MGST1 knockdown leading to depigmentation, increased oxidative stress, and hindered tumor growth. He also determined that inhibiting microsomal glutathione S-transferase 1 (MGST1) in melanoma enhances oxidative stress, increases sensitivity to anticancer drugs, and reduces metastasis, improving the effectiveness of therapies.
Tew examined ME-344, a second-generation isoflavone with anticancer properties in 2019, demonstrating its impact on redox homeostasis, mitochondrial function, and specific targeting of heme oxygenase 1 (HO-1) in lung cancer cells. In 2020, he determined that ME-344 targets VDAC1 and VDAC2 in lung cancer cells, leading to ROS generation, Bax translocation, cytochrome c release, and apoptosis, highlighting their potential as therapeutic targets. He also assessed how reactive oxygen species (ROS) play a dual role in cancer evolution, influencing both tumorigenesis and cell death, and highlighted tumor cell adaptations in metabolism and antioxidant defenses to manage ROS levels during different stages of cancer development.
Awards and honors
1993 – Outstanding Investigator Grant, National Cancer Institute
2003 – Research Award, American Cancer Society Scientific
2010 – Astellas USA Foundation Award, American Society for Pharmacology and Experimental Therapeutics
Bibliography
Selected books
Mechanisms of Drug Resistance in Neoplastic Cells (1988) ISBN 9780127633626
Preclinical and Clinical Modulation of Anticancer Drugs (1993) ISBN 9780849372919
Basic Science of Cancer (2000) ISBN 9781468484397
Advances in Cancer Research (2014) ISBN 9780124071902
Selected articles
Adler, V., Yin, Z., Fuchs, S. Y., Benezra, M., Rosario, L., Tew, K. D., ... & Ronai, Z. E. (1999). Regulation of JNK signaling by GSTp. The EMBO journal, 18(5), 1321–1334.
Townsend, D. M., Tew, K. D., & Tapiero, H. (2003). The importance of glutathione in human disease. Biomedicine & pharmacotherapy, 57(3-4), 145–155.
Townsend, D. M., & Tew, K. D. (2003). The role of glutathione-S-transferase in anti-cancer drug resistance. Oncogene, 22(47), 7369–7375.
Tapiero, H., & Tew, K. D. (2003). Trace elements in human physiology and pathology: zinc and metallothioneins. Biomedicine & Pharmacotherapy, 57(9), 399–411.
Hayes, J. D., Dinkova-Kostova, A. T., & Tew, K. D. (2020). Oxidative stress in cancer. Cancer cell, 38(2), 167–197.
Tew, K.D. Alkylating Agents. In: Principles & Practice of Oncology. Eds. DeVita, Hellman & Rosenberg. pp246–256, 2018.
Tew, K.D. Protein S-Glutathionylation & Glutathione S-transferase P. In: Glutathione. Editor: Leopold Flohé. CRC Press. Chapter 12, 201–214, 2018.
References
Pharmacologists
Alumni of Swansea University
Alumni of the University of London
Medical University of South Carolina faculty
Fellows of the American Association for the Advancement of Science
Fellows of the American Society for Pharmacology and Experimental Therapeutics
Year of birth missing (living people)
Living people | Kenneth Tew | [
"Chemistry"
] | 2,239 | [
"Pharmacology",
"Biochemists",
"Pharmacologists"
] |
75,880,739 | https://en.wikipedia.org/wiki/Ata%20Sarajedini | Ata Sarajedini is an astrophysicist, professional astronomer, academic, author, and podcaster. He is the Bjorn Lamborn Endowed Chair and Professor in Astrophysics at Florida Atlantic University.
Sarajedini's research focuses on resolved stellar populations in galaxies, pulsating variable stars, globular clusters and open clusters. He has authored and co-authored research articles, one book entitled Astronomy Minute Plus and edited the book, Formation of the Galactic Halo... Inside and Out. He is the recipient of the Kitt Peak National Observatory Postdoctoral Fellowship in 1992, a NASA Hubble Postdoctoral Fellowship in 1995, a National Science Foundation CAREER Award in 2001, the 2006 University of Florida Research Foundation Professor Award, and has been recognized as a Fellow of the American Astronomical Society in 2024.
Sarajedini is a member of the American Astronomical Society, the International Astronomical Union and serves as Scientific Editor for the Journals of the American Astronomical Society.
Education and early career
Sarajedini earned a BS degree in Astronomy and Physics from Yale College in 1986, followed by MS and MPhil degrees from Yale University in 1988. Subsequently, he received a PhD from Yale University in 1992.
Career
In 1999, Sarajedini became an assistant professor at Wesleyan University and subsequently at the University of Florida in 2001, where he was later appointed associate professor in 2003 and Professor in 2008. From 2017 to 2020, he served as the Dean of the Charles E. Schmidt College of Science at the Florida Atlantic University, where he has served as the Bjorn Lamborn Endowed Chair and Professor in Astrophysics since 2020.
Sarajedini became the Associate Chair of the Department of Astronomy at the University of Florida from 2009 to 2011 and later Acting Chair from 2011 to 2012. He was appointed the Dean of the Charles E. Schmidt College of Science at the Florida Atlantic University from 2017 to 2020, since then he has been serving as the Bjorn Lamborn Endowed Chair in Astrophysics.
From 2012 to 2016, Sarajedini served as the Associate Editor-in-Chief of The Astronomical Journal and held the position of chair for the NSF Program Review of the National Optical Infrared Laboratory and the Cycle 29 Hubble Space Telescope Time Allocation Committee in 2021. He has been the Scientific Editor for the Journals of the American Astronomical Society since 2016.
In addition to his research and editorial roles, Sarajedini has contributed to science communication as the Scientific Consultant of the PBS television series Star Gazers since 2018. He also records a podcast called Astronomy Minute on Spotify.
Research
Sarajedini has contributed to the field of astrophysics by studying resolved stellar populations in Local Group galaxies including field stars, open and globular clusters in the Milky Way, M31, M33, the Magellanic Clouds, and various nearby dwarf galaxies, mostly by using the Hubble Space Telescope to gather images and data for analysis.
Globular clusters
Sarajedini conducted a series of joint studies to understand globular clusters and stellar populations as part of Hubble Space Telescope Treasury Projects. He was the Principal Investigator of a Treasury project, GO-10775, to study the properties of 65 Galactic globular clusters. Subsequently, he was a co-investigator on the Hubble Space Telescope program, GO-13297, employing UV/blue filters to enhance the characterization of multiple population patterns in Galactic Globular Clusters, shedding light on the details of their formation and the origin of their stellar generations, while also offering insights into C, N, O abundance variations and helium enrichment in these stellar systems.
In a joint research effort, Sarajedini examined the characteristics of main-sequence binaries in 59 Galactic globular clusters, showing that, in most clusters, the binary fraction is lower than in the field, with binaries being more centrally concentrated, and an anti-correlation found between the binary fraction and cluster luminosity, among other correlations. Additionally, he observed that low-density Galactic globular clusters exhibit a minimum binary fraction exceeding 6%, with global fractions ranging from 10 to 50%, and a discernible dependence on cluster age, implying an ongoing binary disruption process within the cluster core.
Stellar formation and population
Sarajedini studied the factors associated with star formation and population in various galaxies. With Andrew C. Layden, he presented deep VI-band photometry of the globular cluster M54, analyzing the age-metallicity relation of the Sagittarius dwarf galaxy with a focus on multiple star formation episodes and confirming M54's age similarity to Galactic globular clusters. He also showcased the detailed characteristics of the M54+ Sagittarius system, revealing old and intermediate-aged star populations with varied metallicities, supporting a closed-box model for Sagittarius' age-metallicity relation. In another collaborative study, he analyzed the population gradients in Local Group dwarf spheroidal galaxies, revealing patterns in Milky Way companions, Tucana, and specific M31 companions, correlating with horizontal-branch morphology and suggesting influences of metallicity and age.
In 2009, Sarajedini collaborated to explore the factors influencing the horizontal branch (HB) morphology in globular clusters, revealing that age, after accounting for metallicity, exhibits a strong correlation with the HB morphology as quantified by the median color difference (Δ(V − I)) between the HB and the red giant branch, suggesting age as the primary second parameter in this context. Alongside colleagues, he identified and characterized multiple stellar populations based on pseudo-two-color diagrams, revealing distinct first (1G) and second-generation (2G) stars with chemical composition differences, and finding an anti-correlation between the fraction of 1G stars and cluster mass. Furthermore, as part of the Panchromatic Hubble Andromeda Treasury program, he investigated about one third of M31's star-forming disk, revealing substantial overdensities in the 10 kpc ring with ages over a billion years, challenging prior assumptions.
Awards and honors
1992 – Kitt Peak National Observatory Fellowship, NSF and NOAO
1995 – Hubble Postdoctoral Fellowship, NASA
2001 – CAREER Award, National Science Foundation
2006 – Research Professor Award, University of Florida Research Foundation
2024 – Fellow - American Astronomical Society
Bibliography
Books
Formation of the Galactic Halo....Inside and Out (1996) ISBN 9781583814284
Astronomy Minute Plus (2021) ISBN 9781792469602
Selected articles
Sarajedini, A., Bedin, L. R., Chaboyer, B., Dotter, A., Siegel, M., Anderson, J., ... & Rosenberg, A. (2007). The ACS survey of galactic globular clusters. I. Overview and clusters without previous Hubble Space Telescope photometry. The Astronomical Journal, 133(4), 1658.
Dotter, A., Sarajedini, A., Anderson, J., Aparicio, A., Bedin, L. R., Chaboyer, B., ... & Siegel, M. (2009). The ACS survey of galactic globular clusters. IX. Horizontal branch morphology and the second parameter phenomenon. The Astrophysical Journal, 708(1), 698.
Marin-Franch, A., Aparicio, A., Piotto, G., Rosenberg, A., Chaboyer, B., Sarajedini, A., ... & Reid, I. N. (2009). The ACS Survey of Galactic Globular Clusters. VII.* Relative Ages. The Astrophysical Journal, 694(2), 1498.
Milone, A. P., Piotto, G., Bedin, L. R., Aparicio, A., Anderson, J., Sarajedini, A., ... & Siegel, M. (2012). The ACS survey of Galactic globular clusters-XII. Photometric binaries along the main sequence. Astronomy & Astrophysics, 540, A16.
Piotto, G., Milone, A. P., Bedin, L. R., Anderson, J., King, I. R., Marino, A. F., ... & Zoccali, M. (2015). The Hubble Space Telescope UV legacy survey of galactic globular clusters. I. Overview of the project and detection of multiple stellar populations. The Astronomical Journal, 149(3), 91.
Sarajedini, A. (2023). The properties of RR Lyrae variable stars in the isolated Local Group dwarf galaxy WLM. Monthly Notices of the Royal Astronomical Society, 521(3), 3847–3860.
References
Astrophysicists
Astronomers
Hubble Fellows
Yale College alumni
Yale University alumni
Florida Atlantic University faculty
American science podcasters
Year of birth missing (living people)
Living people | Ata Sarajedini | [
"Physics",
"Astronomy"
] | 1,833 | [
"Astronomers",
"Astrophysicists",
"Astrophysics",
"People associated with astronomy"
] |
75,880,928 | https://en.wikipedia.org/wiki/Trimethylsulfoxonium | Trimethylsulfoxonium (abbreviated TMSO) is a cation with a formula (CH3)3SO+ consisting of a sulfur atom attached to three methyl groups and one oxygen atom. It has a net charge of +1.
Production
Refluxing dimethyl sulfoxide with methyl iodide can yield trimethylsulfoxonium iodide.
Reactions
Treated with sodium hydride, trimethylsulfoxonium forms dimethylsulfoxonium methylide.
Trimethylsulfoxonium can polymerise to yield polyethylene.
Copper, zinc and palladium ions in water react with trimethylsulfoxonium and sodium hydroxide to form sulfur ylide complexes.
Properties
In the chloride, the sulfur-oxygen bond length is 1.436 Å, sulfur-carbon bond is 1.742. OSC angles are 112.6°, and CSC angles are 106.2°.
List of compounds
References
Organosulfur compounds
Cations
Sulfur ions | Trimethylsulfoxonium | [
"Physics",
"Chemistry"
] | 214 | [
"Matter",
"Organosulfur compounds",
"Organic compounds",
"Cations",
"Sulfur ions",
"Ions"
] |
75,881,955 | https://en.wikipedia.org/wiki/List%20of%20Spanish%20provinces%20by%20life%20expectancy | According to estimation of Eurostat for 2021, Spanish regions have some of the highest life expectancies in the world.
Some Spanish regions are European leaders in this indicator. The Spanish capital region, Community of Madrid, has the highest life expectancy for women in Europe (88.2 years); this is followed by five other Spanish regions: Navarre (87.6 years), Castile and León (87.5 years), Cantabria (87.1 years), Galicia (87.0 years) and the Basque Country (87.0 years). Furthermore, Community of Madrid is second and Navarre is tied for fourth among the regions of Europe with the highest life expenctancy for men.
National Statistics Institute (2023)
Statistics by province
Data source: National Statistics Institute (Spain) (Instituto Nacional de Estadística)
Statistics by autonomous community
Data source: National Statistics Institute (Spain) (Instituto Nacional de Estadística)
Eurostat (2019—2022)
The division of Spain into territorial units 2 level (NUTS 2) coincides with the division of Spain into autonomous communities. By default the table is sorted by 2022.
Data source: Eurostat
Global Data Lab (2019–2022)
Data source: Global Data Lab
Charts
See also
List of countries by life expectancy
List of European countries by life expectancy
Political divisions of Spain
Demographics of Spain
References
Health in Spain
Demographics of Spain
Spain, life expectancy
Spain
Spain-related lists
Spain | List of Spanish provinces by life expectancy | [
"Biology"
] | 301 | [
"Senescence",
"Life expectancy"
] |
75,883,560 | https://en.wikipedia.org/wiki/List%20of%20landing%20ellipses%20on%20extraterrestrial%20bodies | This is a list of the projected landing zones on extraterrestrial bodies. The size of the ellipse or oval graphically represents statistical degrees of uncertainty, i.e. the confidence level of the landing point, with the center of the ellipse being calculated as the most likely given the plethora of variables. Their accuracy has improved from the early attempts in the 1960s; active research continues in the 21st century.
Ellipse table
See also
Moon landing
Mars landing
Great Galactic Ghoul
Cone of Uncertainty
Tropical cyclone forecasting
Deliberate crash landings on extraterrestrial bodies
Notes
References
Spaceflight
Exploration of Mars
Exploration of the Moon | List of landing ellipses on extraterrestrial bodies | [
"Astronomy"
] | 131 | [
"Spaceflight",
"Outer space"
] |
75,883,882 | https://en.wikipedia.org/wiki/Pseudomonas%20graminis | Pseudomonas graminis is a species of bacteria.
References
Pseudomonadales | Pseudomonas graminis | [
"Biology"
] | 19 | [
"Bacteria stubs",
"Bacteria"
] |
75,886,500 | https://en.wikipedia.org/wiki/Han%20%28robot%29 | Han is a social humanoid robot created by the Hong Kong–based company Hanson Robotics. He was first activated in 2015 and debuted the same year at the Global Sources Electronics Fair. His skin is made of Frubber. He can detect people and their gender, age, and emotional expression. He mainly consists of a head that can be mounted on a transparent body allowing people to see his circuitry. According to AI magazine, its main purpose is to help humans find contentment.
Through a mobile phone, Han can make different facial expressions, and can also make basic conversations. He has 40 motors inside his head to make those facial expressions, and multiple cameras inside his eyes and chest.
At RISE conference 2017 in Hong Kong, Han debated with Sophia, another robot by Hanson Robotics about different topics such as the singularity and robot consciousness.
References
Robots
Humanoid robots | Han (robot) | [
"Physics",
"Technology"
] | 173 | [
"Physical systems",
"Machines",
"Robots"
] |
75,889,002 | https://en.wikipedia.org/wiki/Rank-index%20method | In apportionment theory, rank-index methods are a set of apportionment methods that generalize the divisor method. These have also been called Huntington methods, since they generalize an idea by Edward Vermilye Huntington.
Input and output
Like all apportionment methods, the inputs of any rank-index method are:
A positive integer representing the total number of items to allocate. It is also called the house size.
A positive integer representing the number of agents to which items should be allocated. For example, these can be federal states or political parties.
A vector of fractions with , representing entitlements - represents the entitlement of agent , that is, the fraction of items to which is entitled (out of the total of ).
Its output is a vector of integers with , called an apportionment of , where is the number of items allocated to agent i.
Iterative procedure
Every rank-index method is parametrized by a rank-index function , which is increasing in the entitlement and decreasing in the current allocation . The apportionment is computed iteratively as follows:
Initially, set to 0 for all parties.
At each iteration, allocate one item to an agent for whom is maximum (break ties arbitrarily).
Stop after iterations.
Divisor methods are a special case of rank-index methods: a divisor method with divisor function is equivalent to a rank-index method with rank-index function .
Min-max formulation
Every rank-index method can be defined using a min-max inequality: a is an allocation for the rank-index method with function r, if-and-only-if:.
Properties
Every rank-index method is house-monotone. This means that, when increases, the allocation of each agent weakly increases. This immediately follows from the iterative procedure.
Every rank-index method is uniform. This means that, we take some subset of the agents , and apply the same method to their combined allocation, then the result is exactly the vector . In other words: every part of a fair allocation is fair too. This immediately follows from the min-max inequality.
Moreover:
Every apportionment method that is uniform, symmetric and balanced must be a rank-index method.
Every apportionment method that is uniform, house-monotone and balanced must be a rank-index method.
Quota-capped divisor methods
A quota-capped divisor method is an apportionment method where we begin by assigning every state its lower quota of seats. Then, we add seats one-by-one to the state with the highest votes-per-seat average, so long as adding an additional seat does not result in the state exceeding its upper quota. However, quota-capped divisor methods violate the participation criterion (also called population monotonicity)—it is possible for a party to lose a seat as a result of winning more votes.
Every quota-capped divisor method satisfies house monotonicity. Moreover, quota-capped divisor methods satisfy the quota rule.
However, quota-capped divisor methods violate the participation criterion (also called population monotonicity)—it is possible for a party to lose a seat as a result of winning more votes. This occurs when:
Party i gets more votes.
Because of the greater divisor, the upper quota of some other party j decreases. Therefore, party j is not eligible to a seat in the current iteration, and some third party receives the seat instead.
Then, at the next iteration, party j is again eligible to win a seat and it beats party i.
Moreover, quota-capped versions of other algorithms frequently violate the true quota in the presence of error (e.g. census miscounts). Jefferson's method frequently violates the true quota, even after being quota-capped, while Webster's method and Huntington-Hill perform well even without quota-caps.
References
Mathematical theorems
Apportionment methods | Rank-index method | [
"Mathematics"
] | 838 | [
"Mathematical theorems",
"Mathematical problems",
"nan"
] |
75,889,688 | https://en.wikipedia.org/wiki/NBI%20Incorporated | NBI Incorporated was an American computer company based in Boulder, Colorado that offered word processing services. NBI was known for their office automation systems; dedicated hardware platforms for word processing, document production and records management.
Products included:
NBI System 3000
NBI OASys 4000S
NBI OASys 4100S and 4100X
The OASys 4100S and 4100X were introduced in May 1984. The 4100S came with single or dual 5¼" floppy disk drives, and the 4100X with a single disk drive and a 10MB hard drive. Both systems were partially IBM-compatible and came with 128KB RAM.
NBI Incorporated entered Chapter 11 bankruptcy protection in 1991 after several loss-making years.
References
Defunct computer companies of the United States
Defunct computer hardware companies
Defunct computer systems companies
Defunct companies based in Colorado
Companies based in Boulder, Colorado | NBI Incorporated | [
"Technology"
] | 176 | [
"Computing stubs",
"Computer company stubs"
] |
75,893,889 | https://en.wikipedia.org/wiki/Plasmalysis | Plasmalysis is a electrochemical process that requires a voltage source. On the one hand, it describes the plasma-chemical dissociation of organic and inorganic compounds (e.g. C-H and N-H compounds) in interaction with a thermal/non-thermal plasma between two electrodes. On the other hand, it describes the synthesis, i.e. the combination of two or more elements to form a new molecule (e.g. methane synthesis/methanation). Plasmalysis is an artificial word made of plasma and lysis (Greek λύσις, "[dissolution]").
Thermal/non-thermal plasma
Thermal plasmas. can be technically generated, for example, by inductive coupling of high-frequency fields in the MHz range (ICP: Inductively coupled plasma) or by direct current coupling (arc discharges). A thermal plasma is characterized by the fact that electrons, ions and neutral particles are in thermodynamic equilibrium. For atmospheric-pressure plasmas, the temperatures in thermal plasmas are usually above 6000 K. This corresponds to average kinetic energies of less than 1 eV.
Nonthermal plasmas are found in low-pressure arc discharges, such as fluorescent lamps, in dielectrically barrier discharges (DBD), such as ozone tubes, in microwave plasmas (plasma torches, i.e. PLexc oder MagJet) or in GHz-plasmajets. A non-thermal plasma shows a significant difference between the electron and gas temperature. For example, the electron temperature can be several 10,000 K, which corresponds to average kinetic energies of more than 1 eV while a gas temperature close to room temperature is measured. Despite their low temperature, such plasmas can trigger chemical reactions and excitation states via electron collisions. Pulsed coronal and dielectrically impeded discharges belong to the family of nonthermal plasmas. Here the electrons are much hotter (several eV) than the ions/neutral gas particles (room temperature).
Technical aspects
To generate a nonthermal plasma at atmospheric pressure, a working gas (molecular or inert gas, e.g. air, nitrogen, argon, helium) is passed through an electric field. Electrons originating from ionization processes can be accelerated in this field to trigger impact ionization processes. If more free electrons are produced during this process than are lost, a discharge can build up. The degree of ionization in technically used plasmas is usually very low, typically a few per mille or less. The electrical conductivity generated by these free charge carriers is used to couple in electrical power. When colliding with other gas atoms or molecules, the free electrons can transfer their energy to them and thus generate highly reactive species that act on the material to be treated (gaseous, liquid, solid). The electron energy is sufficient to split covalent bonds in organic molecules. The energy required to split single bonds is in the range of about 1.5 - 6.2 eV, for double bonds in the range of about 4.4 - 7.4 eV and for triple bonds in the range of 8.5 - 11.2 eV . For gases that can also be used as process gases, dissociation energies are e.g. 5.7 eV (O2) and 9.8 eV (N2)
Applications of atmospheric pressure plasmas
Atmospheric-pressure plasmas have been used for a variety of industrial applications, including volatile organic compound (VOC) removal, exhaust gas emission treatment and polymer surface and food treatment. For decades, non-thermal plasmas have also been used to generate ozone for water purification. Atmospheric pressure plasmas can be characterized primarily by a large number of electrical discharges in which the majority of the electrical energy is used to generate energetic electrons. These energetic electrons produce chemically excited species - free radicals and ions - and additional electrons by dissociation, excitation and ionization of background gas molecules by electron impact. These excited species in turn oxidize, reduce or decompose the molecules, such as wastewater or biomethane, that are brought into contact with them. Part of the electrical energy is converted into chemical energy. Plasmalysis can thus be used to store energy, for example in the plasma analysis of ammonium from waste water or liquid fermentation residue, which produces hydrogen and nitrogen. The hydrogen thus produced can serve as an energy carrier for a hydrogen economy.
Dissociation mechanisms of gases and liquids
In the following section XH stands for any hydrogen compound, e.g. CH- and NH-compounds.
Thermal dissociation: gaseous hydrogen molecules are being dissociated at temperatures above 3000 K e.g. in a plasma. At temperatures above 3500 K H2 und O2 are dissociated.
electron impact dissociation:
The density of radicals scales with the electron density and higher gas and electron temperatures (thermal dissociation and electron impact).
ion impact dissociation:
dissociative electron attachment:
This process generates negative ions as well as neutral particles. The collision electron is captured by collision excitation. The energy difference between the ground state and the excited state dissociates the molecule. The electron-induced dissociation of water depends on the electron temperature, which influences the ratio of the OH density (n_OH) to the electron density (n_e) significantly. The maximum OH density is reached in the early afterglow when the electron temperature (T_e) is low.
Photoionisation: High-energy photons dissociate molecules
Solvated electrons: Reducing agent in liquid
Dissociation efficiency of different hydrogen sources
Water Electrolysis
Since the focus is always on the most energy-efficient dissociation of chemical compounds, the benchmark is the energy input of the electrolysis of distilled water (45 kWh/kgH2) as in the following reaction equation:
Methane-plasmalysis
A particularly efficient way of generating hydrogen (10 kWh/kgH2) is the methane plasmalysis. In this process, methane (e.g. from natural gas) is decomposed in the plasma under oxygen exclusion, forming hydrogen and elemental carbon, as in the following reaction equation:
Methane plasmalysis offers, among other things, the possibility of decentralized decarbonization of natural gas or, if biogas is used, also the realization of a CO2 sink, whereby, in contrast to the CCS process commonly used to date, no gas has to be compressed and stored, but the elemental carbon produced can be bound in product form.
This technology can also be used to prevent the flaring of so-called "flare gases" by using them as a feedstock for the production of hydrogen and carbon.
Wastewater-plasmalysis
The plasmalysis of wastewater and liquid manure enables hydrogen to be recovered from pollutants contained in the wastewater (ammonium (NH4) or hydrocarbon compounds (COD)). The plasma-catalytic decomposition of ammonia takes place as shown in the following reaction equation:
The treated wastewater is purified in the process. The energy requirement for the production of green hydrogen is approx. 12 kWh/kgH2.
This technology can also be used as ammonia cracking (chemistry) technology for splitting the hydrogen carrier ammonia.
Dissociation of hydrogen sulfide
Hydrogen sulfide - a component of crude oil and natural gas and a by-product in anaerobic digestion of biomass - is also suitable for plasma-catalytic decomposition to produce hydrogen and elemental sulfur due to its weak binding energy.
The energy requirement for the production of hydrogen from H2S is approx. 5 kWh/kgH2.
Reactor geometry
It is apparent that both the reactor geometry and the method by which the plasma is generated strongly influence the performance of the system.
References
Electrochemistry
Process engineering | Plasmalysis | [
"Chemistry",
"Engineering"
] | 1,609 | [
"Process engineering",
"Electrochemistry",
"Mechanical engineering by discipline"
] |
75,898,009 | https://en.wikipedia.org/wiki/HD%2063433 | HD 63433 (TOI-1726, V377 Geminorum) is a G-type main sequence star located 73 light-years from Earth in the zodiacal constellation Gemini, visually close to the star Pollux. It has nearly the same radius and mass of the Sun, hence being classified as a Sun-like star. However, it is much younger than the Sun, less than one tenth as old with an age of about 400 million years. With an apparent magnitude of 6.9, it is not visible to the naked eye, but can be seen with a small telescope or binoculars. Based on its kinematic, rotational and lithium abundance properties, it is part of the Ursa Major Moving Group. There are three exoplanets orbiting it, one is classified as an Earth-sized planet, while the two others are mini-Neptunes.
Characteristics
HD 63433 is a G-type main sequence star with a radius of , a mass of , an effective temperature of and a spectral type G5V. Its properties are quite similar to those of the Sun, which has a spectral type G2V and a temperature of 5772 K. Therefore, it is classified as a solar analog. HD 63433, however, is much younger than the Sun, having an age of 414 million years, just 9% of the solar age of 4.6 billion years. It has a surface gravity of 33.8 g and a rotational period of 6.45 days, which is 3.8 times faster than the Sun.
With an apparent magnitude of 6.92m, it is below the limit for naked-eye visibility, generally defined as 6.5m, which would mean that this star is not visible to the naked eye, but easily visible using a small telescope or binoculars. Despite being faint, HD 63433 is actually the third-brightest star with transiting exoplanets confirmed by the Transiting Exoplanet Survey Satellite, with only Pi Mensae (5.65m) and HR 858 (6.38m) being brighter.
According to stellar kinematics, lithium abundance and stellar rotation, HD 63433 is part of the Ursa Major moving group. It was initially identified as a possible member of this group by Gaidos (1998) and included as a possible member in later analyses, until HD 63433's membership in this moving group was finally confirmed by Mann et al. in 2020. As it is part of this moving group, its age is estimated at million years, the same as the group.
It is located in the northern hemisphere, about 73 light-years from the Earth, in the constellation of Gemini. It is visually close to Pollux, the brightest star in the constellation. HD 63433 is predicted to approach within of the Sun in 1.33 million years. That will make it one of the nearest stars to the Sun. Its closest neighbor is the orange dwarf HD 63991, located at a distance of 2.7 light years.
Variability
HD 63433 belongs to the class of BY Draconis variables, stars have variations in their luminosity due to their rotation together with sunspots and other chromospheric activities. The brightness of the star varies by 0.05 magnitudes over a period of 6.46 days.
It was found to be variable by Gaidos et al. in 2000. The star was given the variable-star designation V377 Geminorum in 2006.
Planetary system
The star HD 63433 is orbited by 3 exoplanets, all discovered by the transit method.
The first ones to be discovered, HD 63433 b and HD 63433 c, are mini-Neptunes that were discovered in by Mann et al. in 2020 using the Transiting Exoplanet Survey Satellite. In 2024, an additional planet was discovered, after an analysis of a transit signal detected by TESS. Named HD 63433 d, it is an Earth-sized planet.
According to theoretical models, the compositions of the mini-Neptunes HD 63433 b and c are mostly silicate and water, with no iron dominance, surrounded by a gaseous envelope which, in the case of planet c, makes up around 2% of the planet.
The planetary system of HD 63433 is quite young, at around 400 million years old, it is only 9.13% as old as the Solar System. HD 63433 d is also the smallest planet that is less than 500 million years old.
HD 63433 b
The middle planet, HD 63433 b, is a mini-Neptune planet that was discovered together with HD 63433 c. HD 63433 b is 2.14 times larger than Earth, but is about 45% smaller than Neptune. The planet has an upper mass limit of , which is 21% greater than the mass of Neptune ( ). These values calculate an upper density limit of 13 g/cm3, 2 times greater than that of Earth, and similar to that of the chemical element Mercury. HD 63433 b orbits its parent star at a distance of – about 5 times closer than Mercury is to the Sun – and completes one revolution every 7 days and 3 hours. The relative proximity of its star makes it hot, with an equilibrium temperature between 769 and 967 Kelvin (496 and 694 °C).
HD 63433 b was probably a mini-Neptune that later lost its atmosphere. Some factors, such as the fact that no absorption of Ly-α was detected during its transit, and its mass-loss timescale being shorter than the age of the planetary system, indicate that it has already lost its primordial atmosphere, and could be a rocky planetary core. However, if HD 63433 b were a rocky core, it would need to be unusually massive and, therefore, a water-rich composition in addition to an atmosphere with a high mean molecular weight could explain both the radius and the non-detection of the Ly-α.
HD 63433 c
The outermost planet, HD 63433 c, is a mini-Neptune planet discovered together with HD 63433 b. It is 2.7 times larger than Earth, but 30% smaller than the Solar System's ice giants, Neptune and Uranus. Being 15.5 times more massive than the Earth, it is more massive than Uranus (), but still less massive than Neptune (). The density of HD 63433 c calculated at 4.6 g/cm3, slightly lower than that of Earth, but greater than the densities of all gas giants in the Solar System.
Orbiting its star at a distance of in an orbital period of 20 days, it is the outermost planet in its planetary system, but still close to its star, making it a warm planet, with a planetary equilibrium temperature estimated between 267 and 406 °C.
Due to the high radiation received from its star, the atmosphere of HD 63433 c, made up of hydrogen, is slowly being stripped away and escaping from the planet, like a hot air balloon. The hot gas escapes into the space at a velocity of 50 km/s, forming a gas cocoon 12 times larger than the planet itself. As its atmosphere evaporates, HD 63433 c will slowly become a super-Earth planet.
HD 63433 d
HD 63433 d was the last planet to be discovered in the system, 4 years after planets b and c. With a diameter of , it is very similar to Earth in size, being only 7% larger, but its mass is currently unknown. It is the innermost planet orbiting HD 63433, having a semi-major axis (mean distance from its star) of and an orbital period of just 4 days. The extreme proximity to its star makes it extremely hot, having a daytime temperature estimated at , hot enough to melt all the minerals present on its surface, as well as being tidally locked, meaning that one half of the planet is always facing towards its star, while the other is always facing away from it. The planet also possibly lacks a substantial atmosphere.
It is believed that the dayside of the planet, always facing its star due to tidal locking, is fully composed of lava due to the high surface temperature, in addition to possibly having volcanic activity. Meanwhile, the nightside of the planet, which never faces its star, may be the opposite, resembling Pluto with glaciers of frozen nitrogen.
HD 63433 d was discovered in 2024, through an analysis of a transit observation made by the Transiting Exoplanet Survey Satellite (TESS). As two other planets had already been discovered in the system, the transit signals of these objects were removed, thus revealing an additional transit signal that reappeared every 4.2 days. Further investigation allowed researchers to confirm that this signal was from another orbiting exoplanet, now called HD 63433 d. The discovery was announced on January 10, 2024, in The Astronomical Journal.
Scientific importance
The HD 63433 planetary system plays an important role in understanding the evolution of planetary systems in the first billion years after formation. As HD 63433 is relatively bright (6.9m) and close (73 ly away), its planets b and c can have their atmospheres characterized by the Hubble Space Telescope and James Webb Space Telescope. This star is also a favorable target for studies of atmospheric mass loss in exoplanets, as it is a young and active star with close-in mini-Neptune planets, in addition to having a negative radial velocity ().
See also
Ursa Major moving group
Exoplanet
Transiting Exoplanet Survey Satellite
Mini-Neptune
Lava planet
List of star systems within 70–75 light-years
Notes and references
G-type main-sequence stars
Solar analogs
Astronomical X-ray sources
Planetary systems with three confirmed planets
Ursa Major moving group
BY Draconis variables
Gemini (constellation)
Durchmusterung objects
063433
038228
Geminorum, V377 | HD 63433 | [
"Astronomy"
] | 2,072 | [
"Gemini (constellation)",
"Astronomical objects",
"Constellations",
"Astronomical X-ray sources"
] |
75,898,016 | https://en.wikipedia.org/wiki/HD%2063433%20d | HD 63433 d (TOI-1726 d) is a confirmed exoplanet orbiting HD 63433, a Sun-like star located 73 light-years away in the constellation Gemini. Its radius is measured at around , which makes it similar to the Earth in size. It was the third (and most recent) exoplanet to be discovered in orbit around this star; the other two, HD 63433 b and c, were discovered in 2020. Orbiting its star at a distance of , HD 63433 d is the innermost planet orbiting HD 63433, and completes an orbit around it just every 4 days. Due to the proximity of its star, the planet is scorching hot, having a temperature estimated at 1260 °C at daytime. The proximity of its star also causes it to be tidally locked.
Physical characteristics
Having a radius of (), it is roughly the size of Earth, but its mass is still unknown. HD 63433 d is the innermost planet in the system, orbiting its star at a distance of and completing one orbital period around it every 4 days and 5 hours. The proximity of its star causes HD 63433 d to be scorching hot, having a daytime temperature estimated at , which is similar to other lava planets such as Kepler-10b and CoRoT-7b, and hot enough to melt all minerals on its surface. In addition, the planet is tidally locked, meaning that one side of the planet always faces its star, while the other side always faces away from it, and it possibly lacks a substantial atmosphere. Tidal locking also happens with the Moon, which has one side always facing Earth.
It is believed that its dayside, always facing its star due to tidal locking, is completely molten and dominated by lava, in addition to possibly having volcanic activity. Meanwhile, the night side of the planet could be as cold as Pluto, having glaciers of frozen nitrogen, depending on its composition.
With an age estimated at 414 million years, it is the smallest known exoplanet less than 500 million years old, and the nearest Earth-sized planet this young.
Importance
The small size, young age and the proximity of its star make HD 63433 an interesting planet for further exploration. According to the HD 63433 d discovery team, this planet and another young terrestrial planets are critical test beds to constrain the current theories of planetary formation and evolution. The study of HD 63433 d could produce valuable information about the formation and evolution of Earth-sized planets.
Discovery
The planet was discovered by a team of scientists led by Benjamin Capistrant and Melinda Soares-Furtado after analyzing a transit observation made by the Transiting Exoplanet Survey Satellite (TESS). The team took the data and removed the transit signals of the other planets, thus revealing an additional transit signal that reappeared every 4.2 days. Later investigations validated that this transit signal was from a third planet around the star HD 63433. The discovery was announced on January 10, 2023, in The Astrophysical Journal.
The discovery of HD 63433 d is part of a project called TESS Hunt for Young and Maturing Exoplanets (THYME), which seeks to discover young transiting exoplanets in moving groups, stellar associations and open clusters.
Host star
The host star of HD 63433 d is HD 63433, a G-type main-sequence star which is located 73 light-years away in the Gemini constellation. Having a radius 91% similar to that of the Sun, and a mass 99% similar, HD 63433 has properties very similar to those of the Sun, being classified as a solar analog. With an apparent magnitude of 6.9, the star cannot be been with the naked eye, but can be with a small telescope or binoculars. HD 63433 is part of the Ursa Major moving group, which makes its age estimated at 414 million years. Other stars located in this group include Alioth and Mizar, located in the Big Dipper.
HD 63433 also hosts two other exoplanets: HD 63433 b and c, two mini-Neptune planets discovered in 2020 by Mann et al.
See also
Lava planet
Kepler-10b, CoRoT-7b and Kepler-20e
HD 63433
Transiting Exoplanet Survey Satellite
List of exoplanets discovered in 2024
Methods of detecting exoplanets
Notes
References
Exoplanets discovered in 2024
Near-Earth-sized exoplanets
Gemini (constellation) | HD 63433 d | [
"Astronomy"
] | 943 | [
"Gemini (constellation)",
"Constellations"
] |
75,898,050 | https://en.wikipedia.org/wiki/Bismuth%28III%29%20sulfate | Bismuth(III) sulfate is an inorganic chemical compound of bismuth with the formula Bi2(SO4)3. It is a hygroscopic white solid that decomposes at 465 °C to bismuth(III) oxysulfate and is isotypic to antimony(III) sulfate.
Production
Bismuth(III) sulfate is most commonly produced from the reaction of bismuth(III) nitrate and sulfuric acid:
Another polymorph of bismuth(III) sulfate can be produced by the treatment of lithium bismuthate(III) with sulfuric acid.
Properties
Bismuth(III) sulfate decomposes at 465 °C to Bi2O(SO4)2. If continually heated, it decomposes to various bismuth oxysulfates and at 950 °C it decomposes to bismuth(III) oxide. Bismuth(III) sulfate hydrolyzes in water.
References
Bismuth compounds
Sulfates | Bismuth(III) sulfate | [
"Chemistry"
] | 210 | [
"Sulfates",
"Salts"
] |
75,898,816 | https://en.wikipedia.org/wiki/Opegrapha%20physciaria | Opegrapha physciaria is a species of lichenicolous (lichen-dwelling) fungus in the family Opegraphaceae. It was first formally described as a new species in 1897 by Finnish lichenologist William Nylander, who placed it in the genus Lecidea. David Hawksworth and Brian J. Coppins transferred it to the genus Opegrapha in 1992.
The fungus produces apothecia (fruiting bodies) that are 0.02–0.3 wide and 0.15–0.21 mm tall. Its , which number eight per ascus, contain three septa and measure 12–17 by 4–6 μm. The fungus grows on the thallus of the foliose lichen species Xanthoria parietina. Opegrapha physciaria is similar to another related lichenicolous fungus, O. rupestris, but is distinguished by different ascospore dimensions (14–22 by 5–8 μm), and a different host (crustose Verrucariaceae species).
Opegrapha physciaria has been recorded from Europe and North America.
References
Opegraphaceae
Lichenicolous fungi
Fungi described in 1897
Fungi of Europe
Fungi of North America
Taxa named by William Nylander (botanist)
Fungus species | Opegrapha physciaria | [
"Biology"
] | 276 | [
"Fungi",
"Fungus species"
] |
75,901,799 | https://en.wikipedia.org/wiki/Joseph%20Starik | Joseph Evseevich Starik (March 23, 1902, Saratov — March 27, 1964, Leningrad) was a Soviet radiochemist, a representative of the Russian radiochemical school, a close associate and a friend of Khlopin Vitaly Grigoryevich, for the first time began systematic studies of ionic and colloidal forms of the state of radionuclides in ultra-diluted solutions. Corresponding member of the USSR Academy of Sciences (1946), three times winner of The Stalin Prize (1949, 1951, 1953).
Biography
In 1924, he graduated from the Department of Chemistry, Faculty of Physics and Mathematics of Moscow University. He worked at the V. G. Khlopin Radium Institute in Leningrad, taught at Leningrad State University (now Saint Petersburg State University). Participant in the nuclear weapons test at the Semipalatinsk Test Site.
The author of the pioneering fundamental work "Fundamentals of Radiochemistry," which summarized all modern ideas about physics, physico-chemistry of sorption processes, methods for determining the forms of the state of radionuclides in extremely dilute state in solutions, gases and solids, the author of works on radioanalytical methods for determining the age of rocks, chemistry of nuclear reactors, chemistry of plutonium.
Scientific papers
Old I. E. On the question of the colloidal properties of polonium// Proceedings of the State Radium Institute. Leningrad. NHTI, 1930, vol. 1, pp. 29–75; 1933, vol.2, pp. 91–103;
Starik I. E. Radioactive methods for determining geological time. Leningrad — Moscow. Chief Editor. chemical lit. 1938. 176 p.
Old I. E. Fundamentals of radiochemistry. Moscow — Leningrad. USSR Academy of Sciences.1959. 460 p.; 2nd ed. Moscow — Leningrad. Science. 1969. 647 p.; translations into English, German. and Japanese. languages, published in the USA under the inaccurate title: Starik I.E. Principles of readiochemistry. LLNL.1985. Monthly Catalog of United States Government Publications, entry No.8050).
Starik I. E. Nuclear geochronology. Moscow — Leningrad, USSR Academy of Sciences, 1961. 630s.
Awards and prizes
3 Order of Lenin (10/29/1949; 1951; 1953)
2 Order of the Red Banner of Labor (06/10/1945; 03/21/1947)
Order of the Badge of Honor (1962)
Medals
Stalin Prize ("'1949", second degree — for leading the development of the technological process of chemical separation of plutonium at the plant No. 817; "'1951"', "'1953"')
V. G. Khlopin Award, for the monograph "Fundamentals of Radiochemistry", 1959
References
External links
A brief biography on the website "Chronicle of Moscow University"
Starik's profile on Russian Academy of Science website
100th anniversary of the scientist's birth.
E. A. Shashukov. The life and creative path of I. E. Starik. Proceedings of the V. G. Khlopin Radium Institute. vol. 12. 2007. pp. 207–209.
1902 births
1964 deaths
Scientists from Saratov
Radiochemists
Moscow State University alumni
Recipients of the USSR State Prize
Recipients of the Order of the Badge of Honour
Recipients of the Order of the Red Banner of Labour
Recipients of the Lenin Prize
Recipients of the Lenin Peace Prize
Academic staff of Saint Petersburg State University | Joseph Starik | [
"Chemistry"
] | 733 | [
"Nuclear chemists",
"Radiochemists",
"Radiochemistry"
] |
75,901,922 | https://en.wikipedia.org/wiki/Steinhaus%20chessboard%20theorem | The Steinhaus chessboard theorem is the following theorem, due to Hugo Steinhaus:Consider a chessboard on which some cells contain landmines. Then, either the king can cross the board from left to right without meeting a mined square, or the rook can cross the board from top to bottom moving only on mined squares.
Two-dimensional variants
Gale proved a variant of the theorem in which the tiles on the chessboard are hexagons, as in the game of Hex. In this variant, there is no difference between king moves and rook moves.
Kulpa, Socha and Turzanski prove a generalized variant of the chessboard theorem, in which the board can be partitioned into arbitrary polygons, rather than just squares. They also give an algorithm for finding either a king route or a rook route.
n-dimensional variants
Tkacz and Turzanski generalize the chessboard theorem to an n-dimensional board:Consider a grid of n-dimensional cubes. Color each cube with one of n colors 1,...,n. Then, there exists a set of cubes all colored i, which connect the opposite grid sides in dimension i.Ahlbach present the proof of Tkacz and Turzanski to the n-dimensional chessboard theorem, and use it to prove the Poincare-Miranda theorem. The intuitive idea is as follows. Suppose by contradiction that an n-dimensional function f, satisfying the conditions to Miranda's theorem does not have a zero. In other words, for each point x, there is at least one coordinate i for which fi(x) is nonzero. Let us color each point x with some color i for which fi(x) is nonzero. By the Steinhaus chessboard theorem, there exists some i for which there is a path of points colored i connecting the two opposite sides on dimension i. By the Poincare-Miranda conditions, fi(x)<0 at the start of the path and fi(x)>0 at the end of the path, and the function is continuous along the path. Therefore, there must be a point on the path on which fi(x)=0 - a contradiction.
See also
A different theorem of Steinhaus, related to arranging rooks on a chessboard, that can be proved using Hall's marriage theorem.
References
Fixed-point theorems | Steinhaus chessboard theorem | [
"Mathematics"
] | 495 | [
"Theorems in mathematical analysis",
"Fixed-point theorems",
"Theorems in topology"
] |
75,902,835 | https://en.wikipedia.org/wiki/GOTO%20%28telescope%20array%29 | The Gravitational-wave Optical Transient Observer (GOTO) is an array of robotic optical telescopes optimized for the discovery of optical counterparts to gravitational wave events and other multi-messenger signals. The array consists of a network of telescope systems, with each system consisting of eight 0.4m telescopes on a single mounting.
As of May 2023 the network consists of two sites, each with two systems. GOTO-N (North) located at the Roque de los Muchachos Observatory (ORM) on the island of La Palma, Spain and GOTO-S (South) located at Siding Spring Observatory (SSO), Australia.
The project is run by an international consortium of universities and other research institutes, including the University of Warwick, Monash University, the University of Sheffield, the University of Leicester, Armagh Observatory, the National Astronomical Research Institute of Thailand, the Instituto de Astrofísica de Canarias, the University of Portsmouth, and the University of Turku.
Design and operation
Telescopes
Each GOTO system can point independently, whilst each unit telescope (UT) has a fixed orientation on the mount so all 8 must be pointed at once. Each UT's pointing is offset from the others to cover the adjacent area of sky, with a small overlap between them. This results in each GOTO system acting as a single large telescope with a very wide field of view (FoV).
The UTs are ASA H400 Newtonian telescopes, each with an aperture of 400mm and a focal length of 960mm (f/2.4). Attached to each telescope is a focuser, filter wheel, and a Finger Lakes Instrumentation (FLI) ML50100 camera, based on the Onsemi KAF-50100 CCD sensor. The fast focal ratio of f/2.4 and large image sensor result in a relatively large field of view, with each GOTO system having a total FoV of approximately 40 square degrees, around 200x the area of the full Moon in the sky. The fast focal ratio also means that only a small amount of time is needed to observe each area of the sky, with each visit requiring only 3 minutes of exposure time.
Identifying transients
GOTO utilises difference imaging to identify changes of existing objects and the appearance of new transients. Images of the sky are matched to previous observations of the same region, finding the difference between these two images will show only the changes in the new image. Sources within these difference images can then be detected automatically. Using difference imaging in this way produces many thousands of candidate sources per image, the vast majority of which are artefacts of the processing and not real transients. GOTO utilises a convolutional neural network based 'real-bogus' classifier to identify which sources are likely to be real.
Gamma-ray bursts
In addition to follow-up of gravitational wave events, GOTO can respond to detections of gamma-ray bursts (GRBs). On September 11, 2023, the Fermi Gamma-ray Space Telescope detected a gamma ray burst (GRB 230911A) and follow-up observations by GOTO discovered an optical counterpart (GOTO23akf/AT 2023shv), which was later confirmed as a GRB afterglow by the Swift X-ray telescope.
All-sky survey
GOTO's typical mode of operation when not performing a follow-up campaign is to survey the entire visible sky. As there are sites located in both the northern and southern hemispheres, the visible sky for GOTO is all areas which are visible at night from anywhere on the Earth. If both sites have good weather conditions the entire visible sky can be observed every 2–3 days.
These observations are processed using difference imaging which allows for serendipitous discovery of transients unrelated to multi-messenger events, like supernovae, tidal disruption events, and fast blue optical transients.
History
The first phase of GOTO's development was the deployment of a prototype system located at the planned site of the northern node, consisting of four unit telescopes on a custom-built mount. The prototype system was deployed during the second LIGO-Virgo Collaboration (LVC) observing run (O2), achieving first light in June 2017 with its official inauguration on July 3, 2017.
The prototype system was active during the first half of the third LVC observing run (O3a), which ran between April and October 2019. During this time GOTO was able to respond to gravitational-wave events and begin observing within one minute of alerts being received (if the source region was visible).
In late 2019 funding was awarded to expand the network with two full GOTO systems a duplicate site in Australia. In 2020 the first full system of the northern node was being deployed, with the second system planned for early 2021 and the Australian site planned for later that year.
The deployment of the second northern system was completed in August 2021 and, despite delays due to the 2021 volcanic eruption, the full northern node was completed in December 2021 with the upgrade of the prototype to the final hardware configuration.
By the end of 2022 the site for the second GOTO node (GOTO-S) had been prepared at Siding Spring Observatory (SSO) and the two domes installed. In May 2023 it was announced that both systems at SSO had been successfully installed.
Discoveries
As of September 11, 2024, data from GOTO has been used in the discovery of 1013 astronomical transients, of which 141 have been classified as supernovae and one as a tidal disruption event.
References
Astronomical surveys
Optical telescopes
Robotic telescopes
Astronomical observatories in La Palma
Siding Spring Observatory | GOTO (telescope array) | [
"Astronomy"
] | 1,165 | [
"Astronomical surveys",
"Works about astronomy",
"Astronomical objects"
] |
75,903,922 | https://en.wikipedia.org/wiki/Gymnopus%20spongiosus | Gymnopus spongiosus, commonly known as the hairy-stalked collybia, is a species of the mushroom-forming fungus family Omphalotaceae. In North America, The fruiting body appears between late summer and fall, and winter along the Gulf Coast. It also appears infrequently in South America. Gymnopus spongiosus is not considered an edible mushroom.
References
Omphalotaceae
Fungi described in 1849
Fungus species
Fungi of North America
Fungi of South America
Taxa named by Moses Ashley Curtis
Taxa named by Miles Joseph Berkeley | Gymnopus spongiosus | [
"Biology"
] | 115 | [
"Fungi",
"Fungus species"
] |
75,908,138 | https://en.wikipedia.org/wiki/International%20Conference%20on%20Automated%20Planning%20and%20Scheduling | The International Conference on Automated Planning and Scheduling (ICAPS) is a leading international academic conference in automated planning and scheduling held annually for researchers and practitioners in planning and scheduling. ICAPS is supported by the National Science Foundation, the journal Artificial Intelligence, and other supporters.
The IPC and PDDL
ICAPS conducts the International Planning Competition (IPC), a competition scheduled every few years that empirically evaluates state-of-the-art planning systems on a collection of benchmark problems. The Planning Domain Definition Language (PDDL) was developed mainly to make the 1998/2000 International Planning Competition possible, and then evolved with each competition. PDDL is an attempt to standardize Artificial Intelligence (AI) planning languages. PDDL was first developed by Drew McDermott and his colleagues in 1998, inspired by STRIPS, ADL, and other sources.
History
The ICAPS conferences began in 2003 as a merge of two bi-annual conferences, the International Conference on Artificial Intelligence Planning and Scheduling (AIPS) and the European Conference on Planning (ECP).
List of Events
References
External links
International Planning Competition (IPC)
Conference locations (ICAPS)
Conference locations (DBLP)
Recurring events established in 1990
Recurring events established in 2003
Artificial intelligence conferences
Computer science conferences
Automated planning and scheduling | International Conference on Automated Planning and Scheduling | [
"Technology"
] | 265 | [
"Computing stubs",
"Computer science",
"Computer science conferences",
"Computer conference stubs"
] |
75,912,306 | https://en.wikipedia.org/wiki/L%C3%A9vy-Leblond%20equation | In quantum mechanics, the Lévy-Leblond equation describes the dynamics of a spin-1/2 particle. It is a linearized version of the Schrödinger equation and of the Pauli equation. It was derived by French physicist Jean-Marc Lévy-Leblond in 1967.
Lévy-Leblond equation was obtained under similar heuristic derivations as the Dirac equation, but contrary to the latter, Lévy-Leblond equation is not relativistic. As both equations recover the electron gyromagnetic ratio, it is suggested that spin is not necessarily a relativistic phenomenon.
Equation
For a nonrelativistic spin-1/2 particle of mass m, a representation of the time-independent Lévy-Leblond equation reads:
where c is the speed of light, E is the nonrelativistic particle energy, is the momentum operator, and is the vector of Pauli matrices, which is proportional to the spin operator . Here are two components functions (spinors) describing the wave function of the particle.
By minimal coupling, the equation can be modified to account for the presence of an electromagnetic field,
where q is the electric charge of the particle. V is the electric potential, and A is the magnetic vector potential. This equation is linear in its spatial derivatives.
Relation to spin
In 1928, Paul Dirac linearized the relativistic dispersion relation and obtained Dirac equation, described by a bispinor. This equation can be decoupled into two spinors in the non-relativistic limit, leading to predict the electron magnetic moment with a gyromagnetic ratio . The success of Dirac theory has led to some textbooks to erroneously claim that spin is necessarily a relativistic phenomena.
Jean-Marc Lévy-Leblond applied the same technique to the non-relativistic energy relation showing that the same prediction of can be obtained. Actually to derive the Pauli equation from Dirac equation one has to pass by Lévy-Leblond equation. Spin is then a result of quantum mechanics and linearization of the equations but not necessarily a relativistic effect.
Lévy-Leblond equation is Galilean invariant. This equation demonstrates that one does not need the full Poincaré group to explain the spin 1/2. In the classical limit where , quantum mechanics under the Galilean transformation group are enough. Similarly, one can construct classical linear equation for any arbitrary spin. Under the same idea one can construct equations for Galilean electromagnetism.
Relation to other equations
Schrödinger's and Pauli's equation
Taking the second line of Lévy-Leblond equation and inserting it back into the first line, one obtains through the algebra of the Pauli matrices, that
,
which is the Schrödinger equation for a two-valued spinor. Note that solving for also returns another Schrödinger's equation. Pauli's expression for spin- particle in an electromagnetic field can be recovered by minimal coupling:
.
While Lévy-Leblond is linear in its derivatives, Pauli's and Schrödinger's equations are quadratic in the spatial derivatives.
Dirac equation
Dirac equation can be written as:
where is the total relativistic energy. In the non-relativistic limit, and one recovers, Lévy-Leblond equations.
Heuristic derivation
Similar to the historical derivation of Dirac equation by Paul Dirac, one can try to linearize the non-relativistic dispersion relation . We want two operators and linear in (spatial derivatives) and E, like
for some , such that their product recovers the classical dispersion relation, that is
,
where the factor is arbitrary an it is just there for normalization. By carrying out the product, one find that there is no solution if are one dimensional constants. The lowest dimension where there is a solution is 4. Then are matrices that must satisfy the following relations:
these relations can be rearranged to involve the gamma matrices from Clifford algebra. is the Identity matrix of dimension N. One possible representation is
,
such that , with , returns Lévy-Leblond equation. Other representations can be chosen leading to equivalent equations with different signs or phases.
References
Eponymous equations of physics
Quantum mechanics
Spinors | Lévy-Leblond equation | [
"Physics"
] | 898 | [
"Eponymous equations of physics",
"Theoretical physics",
"Equations of physics",
"Quantum mechanics"
] |
75,912,651 | https://en.wikipedia.org/wiki/C10H7NO2 | The molecular formula C10H7NO2 (molar mass: 173.17 g/mol) may refer to:
1-Nitroso-2-naphthol
1-Nitronaphthalene
2-Nitronaphthalene
Molecular formulas | C10H7NO2 | [
"Physics",
"Chemistry"
] | 57 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
75,912,820 | https://en.wikipedia.org/wiki/List%20of%20destroyed%20heritage%20of%20the%20Philippines | The following is a list of destroyed heritage in the Philippines. This includes sites which has been totally destroyed either deliberately or through a natural disaster. These were considered as heritage sites at the time of their destruction.
List
Presumed Important Cultural Properties
The following are noted by reliable sources as presumably Important Cultural Properties due to their old age (50+ years at the time of their destruction) or a work by a National Artist.
Reconstructed
The following a heritage (with official designation at the time of their destruction) which were destroyed and later rebuilt.
Notes
References
Philippines
destroyed heritage of the Philippines | List of destroyed heritage of the Philippines | [
"Engineering"
] | 115 | [
"Architecture lists",
"Architecture"
] |
75,914,024 | https://en.wikipedia.org/wiki/Einsteinium%28II%29%20iodide | Einsteinium(II) iodide is a binary inorganic chemical compound of einsteinium and iodide with the chemical formula .
Synthesis
The compound can be prepared via a reaction of and .
Physical properties
The compound forms a solid.
References
Einsteinium compounds
Iodides
Actinide halides | Einsteinium(II) iodide | [
"Chemistry"
] | 60 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,914,185 | https://en.wikipedia.org/wiki/Mina%20Bizic | Mina Bizic is an environmental microbiologist with particular interest in aquatic systems. She is mostly known for her work on organic matter particles and oxic methane production. Since July 2024, she is a Full Professor at the Technische Universität Berlin and Chair of Environmental Microbiomics at the Institute of Environmental Technology. She was named a fellow of the Association for the Sciences of Limnology and Oceanography (ASLO) in 2022, and is serving on the ASLO board of directors where she is chairing the Early Career Committee.
Education and career
Bizic completed her Diploma studies in General Biology, and Hydroecology and Water Protection at the University of Belgrade from 1999 to 2005. Following her diploma, in 2005–2006, she engaged in transdisciplinary academic research in Ancient Jewish texts studies at the European Institute for Jewish Studies in Sweden (PAIDEIA). She later moved to Israel, where she worked for three years at the Kinneret Limnological Laboratory (KLL) of the Israel Oceanographic and Limnological Research (IOLR).
Subsequently, Bizic earned her Ph.D. from the Max Planck Institute for Marine Microbiology in Bremen and the University of Oldenburg as part of The International Max Planck Research School of Marine Microbiology (MarMic)
Her doctoral thesis was titled "Polyphasic comparison of limnic and marine particle-associated bacteria". Following her Ph.D., she conducted a postdoc at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB). In 2019, Bizic obtained a DFG German Research Foundation independent researcher grant.
Research
During her investigations into marine and lake snow, Bizic and her collaborators developed a novel experimental device, a flow-through rolling tank, which facilitates long-term experiments on marine and lake snow while addressing biases inherent in closed systems, commonly referred to as the bottle effect. Using this device, Bizic demonstrated that microbial degradation of marine snow takes longer than predicted using closed experimental systems. This finding implies that the biological carbon pump may sequester more carbon than experimentally estimated.
In a subsequent study, Bizic and her colleagues conducted the first research utilizing molecular tools to focus on individual marine and lake snow particles rather than pooling thousands together. This groundbreaking study revealed that particles from the same source are colonized by different bacteria, in what appears to be a stochastic colonization process. Furthermore, the study highlighted that, at the early stages of colonization, bacterial succession is primarily driven by competition rather than a change in the quality of available organic matter.
In parallel with her work on marine and lake snow, Bizic has delved into aerobic methane production, a phenomenon known as "The Methane Paradox". This process is increasingly recognized as a significant source of the potent greenhouse gas methane in aquatic systems. Bizic and her colleagues were the first to demonstrate the conversion of methylamines to methane under aerobic conditions. This process was later comprehensively characterized by Wang and colleagues. Subsequently, Bizic and her team revealed that cyanobacteria, the most abundant photosynthetic organisms on Earth, emit methane as a byproduct of photosynthesis. The implications of this discovery were explored by Bizic in a subsequent opinion paper.
Recognition and activities
In 2022, Bizic was elected to the Board of Directors of the Association for the Sciences of Limnology and Oceanography (ASLO). She currently serves as a member at large and chairs the Early Career committee of ASLO, organizing activities for the benefit of early career scientists such as the promotion of early creer scientist from historically excluded groups as well as organizing webinars to improve the mental well-being of scientists. Bizic's contributions to aquatic research and to ASLO were further acknowledged when she was named an ASLO fellow in 2022.
Beyond her academic endeavors, Bizic is involved in the Global Lake Ecological Observatory Network (GLEON), and as of 2024, serves as a member in their committee for inclusive collaboration. Bizic has participated in interviews, events and panel discussions addressing the role of women in science such as the Marthe Vogt podcast and the Soapbox Science.
Personal life
Mina Bizic was born in Belgrade, Serbia, and has lived in Sweden and Israel. In 2009, she relocated to Germany. She is the sibling of opera singer David Bizic and is married to fellow scientist Danny Ionescu, with whom she has two children.
References
Notes
Sources
External links
Living people
21st-century biologists
21st-century Serbian people
21st-century Serbian women
21st-century women scientists
Academic staff of Technische Universität Berlin
Environmental scientists
Microbiologists
Scientists from Belgrade
Serbian biologists
Serbian expatriates in Germany
Serbian women scientists
Women ecologists
Women marine biologists
Women microbiologists
Year of birth missing (living people) | Mina Bizic | [
"Environmental_science"
] | 990 | [
"Environmental scientists"
] |
75,916,379 | https://en.wikipedia.org/wiki/Domain%20separation | In cryptography, domain separation is a construct used to implement multiple different functions using only one underlying template in an efficient way. The domain separation can be defined as partitioning of the domain of a function to assign separate subdomains to different applications of the same function.
For example, cryptographic protocols typically rely on random oracles (ROs, functions that return a value fully determined by their input yet otherwise random). The security proofs for these protocols are based on the assumption that the random oracle is unique to the protocol: if two protocols share the same RO, the assumptions of the proof are not met anymore. Since creating a new cryptographic primitive from scratch each time an RO is needed is impractical, multiple ROs (say, RO1 and RO2) are produced by prepending unique domain separation tags (DSTs, also known as domain separators) to the input of a base oracle RO:
RO1(x) := RO("RO1" || x)
RO2(x) := RO("RO2" || x)
where "RO1" and "RO2" are the strings representing the unique DSTs and || is a concatenation operator. If the underlying RO function is secure (say, it is a cryptographic hash), RO1 and RO2 are statistically independent. The technique was originally proposed by Bellare & Rogaway in 1993.
Uses
The domain separation construct can be used for multiple purposes:
providing independent ROs for protocols;
extending the output size of an RO (for example, by using the RO multiple times (numbered from 1 to L), each time using a representation of oracle number as a DST. This technique is called "counter mode" due to its similarity to the counter mode of a block cipher;
"keying" the oracle by using an encryption key as a DST.
In the practical sense, the domain separation can provide "customization", an equivalent of the strong typing in programming: it enforces the use of independent calculations for different tasks, so an attacker that had learned a result of one calculation will get no information about another one.
Kinds of functions
Domain separation can be used with functions implementing different cryptographic primitives.
Hash functions
Domain separation is most commonly used with hash functions. The input domain of a hash function is practically unlimited, it is easy to partition it among any number of derived functions, for example, by prepending or appending of a DST to the message.
Domain separation is used within the implementation of some hash functions to produce multiple different functions from the same design. For example, in SHA-3 the domain separation makes sure that the differently named functions (like SHA3-512 or SHAKE128) are independent.
Symmetric ciphers and MACs
The security of symmetric ciphers and MACs critically depends on the key not being used for other purposes. If an application needs multiple keys but has only one source of keying material, it would typically employ a key derivation function to produce the keys. KDFs can usually produce output of arbitrary length, so they can be used to generate any number of keys.
Also, just like hash functions, some symmetric ciphers and MACs use domain separation internally.
Signatures
In many cases, it is desirable to use a single signing key to produce digital signatures for different purposes. If this is done, it is important to make sure that signed messages intended for one purpose cannot be used for the other. A simple way to achieve this is to add to each message an identifier specifying the purpose, and to reject a message if the identifier doesn't match.
References
Sources
Cryptography | Domain separation | [
"Mathematics",
"Engineering"
] | 750 | [
"Applied mathematics",
"Cryptography",
"Cybersecurity engineering"
] |
75,918,152 | https://en.wikipedia.org/wiki/Russula%20rhodocephala | Russula rhodocephala, also known as the redhead russula, is a species of gilled mushroom. It typically grows in association with pine trees. It is primarily found on the Pacific coast of western North America, although mushrooms with 97 percent genetic similarity are known from Asia. This species was formerly considered to be Russula sanguinaria, from which it has been recently separated due to differences in genetics and geographic distribution. It has an extremely acrid taste when raw, and is described as having a "disgusting" flavor when cooked.
See also
List of Russula species
References
rhodocephala
Fungi described in 2017
Fungi of North America
Fungus species | Russula rhodocephala | [
"Biology"
] | 137 | [
"Fungi",
"Fungus species"
] |
75,919,362 | https://en.wikipedia.org/wiki/Jelleine | Jelleine is a family of peptides, isolated from the royal jelly of Apis mellifera iberiensis, a subspecies of the honey bee. This new family has the potential to be used in the development of new drugs.
Discovery
Jelleines were first isolated in 2004 by the research group of Professor Mario Sergio Palma at São Paulo State University, Brazil. First, he collected royal jelly from a group of honey bee larvae and purified the results by reverse phase, high-performance liquid chromatography. This purified royal jelly showed antimicrobial activity against different bacteria. So far, four peptides have been found in this family, each one containing the carboxamide C-terminal.
Health benefits
Fungal spores lead to respiratory disease in more than 10 million people. Compared to current antifungal agents, Jelleine has the potential to be a less toxic and more effective agent. Jelleine-I has been known to work against Candida albicans, C. tropicalis, C. parapsilosis, and C. glabrata. Jelleine-I causes damage that promotes microbial lysis. In addition, Jelleine has been shown to stimulate the formation of reactive oxygen species which improve its defense against Candida. In a test, Kunming mice were infected with C. Albicans. Then one hour after infection they were given different doses of jelleine-I over a period of 7 days. At the end of the experiment, the antifungal effect of Jelleine-I kept 60% of its group alive, while a separate group given Fluconazole only kept 40% alive and the untreated control group had a 100% mortality rate.
Jelleine also has an antiparasitic ability against pathogens such as Leishmania. Most drugs administered are both toxic and prone to side effects. Jelleine-I has low anti-leishmania activity, being able to stop promastigotes but having no effect on the amastigotes.
Jelleine-I and its halogenated analogues show potential as an immunologic adjuvant in the treatment of colorectal cancer. These peptides inhibit Fusobacterium nucleatum, an anaerobic bacterium of the oral microbiota that is highly active in the altered microecology of the gut and is closely associated with the initiation and progression of CRC.
References
Peptides
Bee products
Antiparasitic agents
Colorectal cancer | Jelleine | [
"Chemistry",
"Biology"
] | 518 | [
"Biomolecules by chemical classification",
"Antiparasitic agents",
"Molecular biology",
"Biocides",
"Peptides"
] |
75,922,777 | https://en.wikipedia.org/wiki/Marchantia%20paleacea | Marchantia paleacea is a species of liverwort found in North America, Europe, and eastern Asia. It has been employed as a model organism to study plant-fungal symbioses.
References
Marchantiales
Plants described in 1875
Plant models
Taxa named by Antonio Bertoloni | Marchantia paleacea | [
"Biology"
] | 62 | [
"Model organisms",
"Plant models"
] |
75,922,790 | https://en.wikipedia.org/wiki/Einsteinium%28II%29%20bromide | Einsteinium(II) bromide is a binary inorganic chemical compound of einsteinium and bromine with the chemical formula .
Synthesis
The compound can be prepared via a reduction of with .
References
Einsteinium compounds
Bromides
Actinide halides | Einsteinium(II) bromide | [
"Chemistry"
] | 50 | [
"Bromides",
"Salts",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,924,429 | https://en.wikipedia.org/wiki/Nuptial%20tubercles | Nuptial tubercles or breeding tubercles (also called pearl organs or nuptial efflorescence) are noticeable skin roughness or horny nodules that form on male fish during breeding. They are made of keratin, the same material as hair, hooves, and fingernails.
Use and description
These tubercles are dermal structures present in 15 families of fish belonging to 4 orders of Actinopterygii – Salmoniformes, Gonorhynchiformes, Cypriniformes and Perciformes are used in the courtship and reproduction process. They consist of partially or fully keratinised cells that form in certain regions, used to stimulate females during courtship. Their development is stimulated by hormones secreted by the pituitary and adrenal glands, and is induced shortly before the breeding season and discarded after. In some species, at least, there is a correlation between the level of androgens present in the endocrine system and the volume and complexity of tubercle growth.
They normally form on the heads of male fish, often covering the whole of the top part of the snout, but may also occur on fins, or anywhere else on the scaled integumentary system. The actual purpose of nuptial tubercles is not definitively known. There are many theories about their function, which include: use to stimulate females during courtship, in aggressive rituals performed by males during mate selection, to maintain contact between individuals during reproduction, or in defence of the nest from predators. There is definite proof that they grow mainly on areas with greater mechanical stress, which means that those species that head-butt females to stimulate them to release eggs will have more on the head, whereas those that dig nests in gravel substrates will develop them more on their fins. Nuptial tubercles occasionally develop on female fish also, but this is rare, and they are often barely visible to the naked eye.
Nuptial tubercles have been described as an honest signal of the general health of the male bearer, in common with other biological ornaments. Indeed, research has proven a correlation between tubercle density and parasite resistance, though it is not always a positive correlation.
In species that use lek mating, the females choose the males with the roughest skin, but were not confused by males that had papillomatosis (a skin disease resulting in rough skin).
The presence of nuptial tubercles has been used to distinguish speciation. The genus Leucos was described from similar Rutilus species in Europe as they do not develop them. Similarly, the description of Messinobarbus (now a synonym of Luciobarbus) in 1994 was an attempt to distinguish those species with them from Barbus that do not have them.
Similar structures in other fishes
Visually similar structures to nuptial tubercles are produced by male loricariid catfishes during the mating season, in similar places to nuptial tubercles (snout and fins). These are actually hypertrophied odontodes, which are therefore dermal teeth, rather than keratin, and are covered by flesh containing taste buds. It has been proposed that these ornaments may assist breeding success by mimicking fry, tempting females to lay their eggs in the nest cave of a successful male, already guarding his own offspring.
Instead of tubercles, cichlid males produce nuchal humps (koks), where additional fat is laid under the skin over the skull forming a hump on the head. This trait has been developed to an extreme in the hybrid Flowerhorn cichlid, by selective breeding in the aquarist hobby.
See also
Nuptial pad - a similar ornament of frogs
References
Further reading
Animal anatomy
Ethology
Ichthyology
Fish reproduction | Nuptial tubercles | [
"Biology"
] | 781 | [
"Behavioural sciences",
"Ethology",
"Behavior"
] |
75,926,284 | https://en.wikipedia.org/wiki/Pertica%20%28unit%29 | The pertica (from , measuring rod) was a pre-metric unit of either length or area, with the values varying by location. For a similar unit in Northern Europe, see perch.
Ancient Rome
In the Ancient Rome, pertica, also called decempeda, was a unit of length, usually equal to 10 Roman feet (pedes), or approximately 2.96 meters. The variants of pertica contained 12 and 15 pedes. Isidore of Seville (per Codex Gudianus) states that sometimes a pertica of 10, 12, 15, or 17 pedes was used by agrimensores (Roman land surveyors) to accommodate the richness of the soil and approximately even the yield per unit area. Kidson highlights the near-perfect match between the pertica of 17 pedes and the English version of the perch.
The same names, pertica and decempeda, were used for the surveyor's tool, a rod of the corresponding length with subdivision into smaller units, similar to the Ancient Greek kalamos.
Italy
The linear unit in Italy was about 3 meters, area unit contained about 600 square meters. After switching to the metric system, the unit became equal to 1 decare.
The regional area values significantly varied per province (in square meters):
Bergamo 662;
Como (milanese) 655;
Cremona 808;
Pavia 770;
Piacenza 762;
Sondrio 688.
References
Sources
Ancient Roman units of measurement
Obsolete units of measurement
Units of length
Units of area | Pertica (unit) | [
"Mathematics"
] | 319 | [
"Obsolete units of measurement",
"Units of area",
"Units of length",
"Quantity",
"Units of measurement"
] |
75,926,342 | https://en.wikipedia.org/wiki/Aoraki%20Mackenzie%20International%20Dark%20Sky%20Reserve | The Aoraki Mackenzie International Dark Sky Reserve is an area of that was designated as an International Dark Sky Reserve by the International Dark-Sky Association in June 2012. The reserve is located in the Mackenzie District in the South Island of New Zealand. At the time of the designation in 2012, the reserve was the largest in the world, and the only reserve of its type in the Southern Hemisphere.
The area covered by the reserve includes the Aoraki / Mount Cook National Park and the Mackenzie Basin, Lake Pukaki and Lake Tekapo. The main settlements within the reserve are Mount Cook Village, Twizel, and Lake Tekapo (town).
The night sky brightness in the reserve ranks at a level 2 on the nine-level Bortle Dark-Sky Scale, representing a truly dark site with high astronomical observability of celestial objects. The low level of light pollution in the area of the reserve has been supported by a lighting by-law that was included in the Mackenzie District Plan in 1981.
The Mount John University Observatory is located in the reserve, and is the main astronomical research observatory in New Zealand. There is also a star-gazing tourism venture, Dark Sky Project, operating in the Lake Tekapo township.
References
External links
Aoraki Mackenzie International Dark Sky Reserve, podcast dated 8 August 2015 at RNZ
Dark Sky Project
Lighting and the Aoraki Dark Sky Reserve at Mackenzie District Council
Stargazing & Astrophotography at Mackenzie Region
2012 establishments in New Zealand
Aoraki Mackenzie International Dark Sky Reserve
Aoraki / Mount Cook National Park
Astronomy in New Zealand
International Dark Sky Reserves
Mackenzie District | Aoraki Mackenzie International Dark Sky Reserve | [
"Astronomy"
] | 332 | [
"International Dark Sky Reserves",
"Dark-sky preserves"
] |
75,926,684 | https://en.wikipedia.org/wiki/Richard%20J.%20Buttery | Richard John Buttery is a British-American theoretical plasma physicist and the director of the DIII-D National Fusion Facility at General Atomics. He is an elected fellow of the Institute of Physics and the American Physical Society.
Early life and career
Buttery obtained a B.Sc. in Physics and a Ph.D. in theoretical particle physics from the University of Manchester in 1990 and 1994 respectively. His dissertation was on the photon fragmentation function in quantum chromodynamics.
Following his graduation, Buttery joined the United Kingdom Atomic Energy Authority, where he worked at the Mega Ampere Spherical Tokamak (MAST) and the Joint European Torus (JET) for 16 years until 2009. In that year, Buttery relocated to the United States and joined General Atomics as a program planning coordinator for the DIII-D National Fusion Facility. In 2012, Buttery became the Director for Experimental Science and has been leading the DIII-D scientific team ever since.
Scientific contributions
Buttery is a member of the American Physical Society Division of Plasma Physics Executive Committee and the U.S. Burning Plasma Organization Council.
Honors and awards
Buttery was elected as a fellow of the Institute of Physics in 2009.
In 2019, he was elected as a fellow of the American Physical Society for "pioneering contributions to the understanding of magnetohydrodynamics stability in tokamak plasmas, including the physics of tearing modes and magnetic field errors, and for outstanding scientific leadership of national and international fusion research ".
References
Living people
Year of birth missing (living people)
Alumni of the University of Manchester
Plasma physicists
Fellows of the American Physical Society | Richard J. Buttery | [
"Physics"
] | 331 | [
"Plasma physicists",
"Plasma physics"
] |
75,929,885 | https://en.wikipedia.org/wiki/Hansi%20Neumann%20flight | The Hansi Neumann flight was the first flight to evacuate refugee children from Prague, Czechoslovakia, to Croydon, England, in January 1939, in the lead up to the Second World War. Part of the Czech kindertransport, it was completed in a Dutch Douglas aircraft of KLM, and organised by the Barbican Mission to Jewish People and the British Committee for Refugees from Czechoslovakia (BCRC). Around 18 Jewish children were on the flight.
News of the flight was covered by journalists and photographers at the time. A two and a half minute film was taken of the departure by Julius Jonak of Universal News. Images of the BCRC's Nicholas Winton and the child Hansi at the airport, inspired a memorial later placed at the main railway station, Prague.
Background
In the lead up to the Second World War, the Barbican Mission to Jewish People and the British Committee for Refugees from Czechoslovakia (BCRC), organised flights to evacuate mostly Jewish children from Prague to England, part of the Czech kindertransport. The first of these flights was one of two Dutch Douglas aircraft of KLM, made available in January 1939.
The Barbican Mission was an organisation whose intention was to bring Jewish children from Prague to Britain and bring them up as Christians. It declared that its mission was "to proclaim the Gospel of our lord Jesus Christ to the Jews". Key members were Reverends Isaac Emmanuel Davidson, the Barbican Mission's director, his wife Lucy, and William Edward Wallner, the representative in Prague. The BCRC had been established in late October 1938 in response to the increase in requests for refuge abroad. Its purpose was to make arrangements and allocate funds for Czech refugees who may travel to Britain. One of its associates was Nicholas Winton, a 29 year old British stock-broker of German-Jewish origin. In December 1938, Marie Schmolka, Hannah Steiner and Martin Blake, asked him to hold off his skiing holiday in the Alps and visit Prague instead. The message he received began "600 children in Prague and elsewhere in Czechoslovakia urgently require emigration to England." In Prague, he became acquainted with the BCRC's Doreen Warriner and other officers involved in rescuing refugees. Winton remained there for around three weeks, helping with others, to organise the evacuation of mostly Jewish children refugees to England. At the time, KLM had been well established, was popular and successful at Croydon, with Spry Leverton as the KLM's longstanding representative there, and with their main office at The Hague.
Flight
On 9 January 1939, Davidson had given a press release from Hatton House, Lubbock Road, the residence of F. E. Fehr, regarding growing anti-semitism and need to evacuate at risk children in Prague.
Departure from Prague
One of several flights organised by the Barbican Mission before 15 March 1939, the first flight of all Jewish children left Prague in January 1939. KLM made available two Dutch Douglas aircraft that day. At the scene of departure, were the children, their parents, Winton, photographers and journalists.
Winton's scrapbook, Saving the Children, Czechoslovakia 1939, notes that "the first party of children today left Prague. This was fixed up by the Barbican Mission to the Jews in London and transport was arranged by us. Being the first lot of kids to leave Czechoslovakia it aroused much attention and cinema men and journalists were very much in evidence". The cameraman noted "today on the aerodrome of Ruzyn nearly 30 children of refugees took leave of their parents. Two Dutch Douglas airplanes brought them to Rotterdam and from there to London. This is the charitable work of the Barbican Mission of London, under the direction of Rev. Wallner. He intends to give 60 children altogether a new home in London where they will remain till their 18th year".
Arrival at Croydon
The flight landed at Croydon airport, South London, in the afternoon of 12 January 1939. The children received a formal reception upon arrival at the airport. There, they would have been required to complete entry formalities and undergo medical inspections. They were met by W. A. Leon, of the movement for the care of children from Germany. Also meeting the children were the Davidsons, who took them by bus to Brockley. They were first housed at Christ Church Parish Hall, some later being transferred to Seven Trees, a large house acquired by the Barbican Mission, on Lubbock Road, Chiselhurst. Most children were found homes in the Chislehurst area.
Children
The number of children on the flight was reported as 18. Their parents included lawyers, doctors and journalists. Hansi Neumann, also referred to as Hansi Beck, was born on 28 August 1935. He died in April 1940 from complications following an ear infection. An account in the Prism : An Interdisciplinary Journal for Holocaust Educators says that his father found his way to England to look for the boy, while the rest of his family will killed. Other sources say both his parents died later in a concentration camp. Ilse Ryder was 10 years old at the time. Two months later she was reunited with her mother, who arrived on a domestic permit. Other children included Gert Verging, Eva Somers, Eva Heller Lewis, Renata Oren, and Ewald Heller.
Swedish Airlines also contributed to subsequent airlifts. On 8 March 1939, another group of 20 children left Prague by flight, and a further group left on 14 March. By the onset of the war, two houses on Lubbock Road had been acquired, one for 52 boys and the other for 26 girls. No further children were moved.
Media coverage and legacy
A two and a half minute film was made of the departure. The camera was operated by Julius Jonak, and the film was produced by Universal News.
News of the flight was covered by journalists and photographers at the time and has since received widespread media attention, with Winton featured in photographs with Hansi.
The artist Flor Kent, based a memorial at the main railway station, Prague, on an image of Winton and Hansi taken just prior to the departure. A memorial plaque to the Davidsons was erected at Lubbock Road, Chislehurst.
Notes
References
Further reading
Lucy V. Davidson, For a Future and a Hope: The Story of the Houses of Refuge in Chislehurst, ed. John S. Ross (Chislehurst: Christian Witness to Israel, 1989).
1939 in Czechoslovakia
1939 in the United Kingdom
Dutch civil aircraft
Civil aviation in the Czech Republic
International response to the Holocaust
Kindertransport
Children in World War II
The Holocaust and the United Kingdom
Jews who immigrated to the United Kingdom to escape Nazism
Jewish emigration from Nazi Germany
Rescue of Jews during the Holocaust
Croydon Airport
Aviation history of England
1939 in aviation
Non-combat military operations involving the United Kingdom
Airlifts
January 1939 events in Europe | Hansi Neumann flight | [
"Biology"
] | 1,405 | [
"Rescue of Jews during the Holocaust",
"Behavior",
"Altruism"
] |
75,930,802 | https://en.wikipedia.org/wiki/Oppo%20Find%20X7 | The Oppo Find X7 is a series of two Android-based smartphones manufactured by Oppo as part of its flagship Find X series. Unveiled as successors to the Oppo Find X6 series, both phones were launched on 8 January 2024. Just like its predecessor the Find X6 series, the Find X7 series were released exclusively for the mainland Chinese market.
Lineup
The Find X7 series consists of two devices - the regular Find X7 and the top of the line Find X7 Ultra. As the first "Ultra" phone in the flagship Find X series, the Find X7 Ultra is also being touted as the first phone to incorporate two periscope telephoto cameras.
Design
Both the Find X7 and the Find X7 Ultra feature curved displays and aluminium frames. The Find X7 features a curved display, while the Find X7 Ultra has a slightly larger screen with a higher 1440p resolution. Both display systems are 10-bit HDR10+ capable. The Find X7 is IP65 protected, while the Find X7 Ultra features IP68 water and dust resistance.
The Find X7 smartphone is available in four different colour options, namely Black, Ocean Blue, Sepia Brown and Purple. The Black and Purple variants have all-glass back panels, while the Ocean Blue and Sepia Brown colour options come with dual-tone glass and vegan leather design. The Find X7 Ultra is available in Ocean Blue, Sepia Brown and Tailored Black colourways, all of which feature similar dual-tone glass and leather backs.
The Find X7 series is the first within Oppo's Find X lineup to introduce an alert slider, a design copied from the company's subsidiary OnePlus.
Specifications
Hardware
The Find X7 is powered by MediaTek Dimensity 9300 and operates on a 1x3.25 GHz Cortex-X4, 3x2.85 GHz Cortex-X4 and 4x2.0 GHz Cortex-A720 octa-core system. The flagship Find X7 Ultra uses Snapdragon 8 Gen 3, the highest specced Snapdragon chip in 2024. It operates on a more advanced octa-core system comprising 1x3.3 GHz Cortex-X4, 5x3.2 GHz Cortex-A720 and 2x2.3 GHz Cortex-A520.
Both the Find X7 and the Find X7 Ultra offer UFS 4.0 without expandable storage and Dolby Atmos stereo speakers with active noise cancellation. Biometric options include an optical fingerprint scanner and facial recognition. While both phones come equipped with either 12 or 16 GB of RAM, the Find X7 is the only phone in the series to offer up to 1 TB of UFS4.0 flash memory, whereas the Find X7 Ultra has either 256 GB or 512 GB UFS 4.0 flash memory options.
Camera
The Find X7 has a triple camera setup consisting of a 50 MP main sensor, a 50 MP ultrawide sensor and a 64 MP periscope telephoto lens capable of 3x optical zoom.
The Find X7 Ultra incorporates a quad-camera setup comprising a 50 MP 1-inch type Sony LYT-900 main sensor, a 50 MP Sony LYT-600 ultrawide sensor, a 50 MP Sony IMX890 2.8x-periscope telephoto lens and a 50 MP Sony IMX858 6x-periscope telephoto lens. Oppo has claimed that the Find X7 Ultra's quad-camera system is capable of covering between 14mm to 270mm equivalent focal lengths.
Both the Find X7 and the Find X7 Ultra are equipped with a 32 MP front-facing camera capable of 4K selfie video resolution. GSMArena speculated that either a Sony IMX709 or LYT-506 sensor is used for the front-facing camera. The Find X7 series also features software-based tuning co-developed with Hasselblad, with built-in Hypertone Image Engine purportedly designed to enhance computational photography.
Software
The Find X7 and Find X7 Ultra run on ColorOS 14, which is based on Android 14.
See also
List of large sensor camera phones
References
External links
Official website
Find X7
Android (operating system) devices
Mobile phones with multiple rear cameras
Mobile phones with 4K video recording
Flagship smartphones
Mobile phones introduced in 2024 | Oppo Find X7 | [
"Technology"
] | 911 | [
"Phablets",
"Crossover devices",
"Flagship smartphones"
] |
75,930,939 | https://en.wikipedia.org/wiki/Online%20Safety%20Act%20%28Sri%20Lanka%29 | The Online Safety Act, No. 9 of 2024 is a Sri Lankan Internet safety act aimed at regulating its citizens' Internet usage. It was announced in September 2023 and passed by Parliament on 24 January 2024 by a 108–62 vote.
The bill has been criticised by human rights groups, journalists and opposition politicians as a means of stifling freedom of speech.
Provisions
The bill aims to "make provisions to prohibit online communication of certain statements of fact in Sri Lanka" and "prevent the use of online accounts and inauthentic online accounts for prohibited purposes." It proposes making the posting of content that is deemed "illegal" by a five-member commission, the Online Safety Commission, punishable by jail time. It also makes social media platforms such as Facebook, Google and Twitter liable for such content.
President Ranil Wickremesinghe said the bill was intended to combat cybercrime, including data theft, child abuse and online fraud. According to Public Security Minister Tiran Alles, 8,000 instances of cybercrime were logged in Sri Lanka in 2023.
Reception
The bill has resulted in concerns that the government is attempting to suppress freedom of speech. Following the passage of the bill, a group of activists and opposition members protested outside the Parliament Building.
Domestic
Opposition politician Rauff Hakeem said the bill was "a manifestation of a government which is trying to dismantle even the remaining few safeguards for freedom of expression in this country and to destroy democracy." Samagi Jana Balawegaya politician Harsha de Silva called the bill "a threat to our democracy", saying that it would have "a severe negative impact on expanding e-commerce in Sri Lanka, to provide jobs to our youth and help our economy, which is in desperate need of growth."
Alles said the bill's intent was "not to suppress the media or the opposition", adding, "Any complaint will be taken up by the commission, who will be appointed by the president and they will decide how to act."
International
The Asia Internet Coalition opposed the bill when it was announced in September 2023, with managing director Jeff Paine saying, "the bill provides for a draconian system to stifle dissent and Sri Lankans' rights to expression." Human Rights Watch also criticised the bill, saying the Online Safety Commission would be able to arbitrarily decide "what online speech is 'false' or 'harmful', remove content, restrict and prohibit internet access, and prosecute individuals and organizations".
Julie Chung, the United States Ambassador to Sri Lanka, expressed concern about the potential impact of the bill. Russian ambassador Levan Dzhagaryan said the bill was purely an internal matter for Sri Lanka.
See Also
Personal Data Protection Act (Sri Lanka)
References
Acts of the Parliament of Sri Lanka
2024 in Sri Lanka
2024 establishments in Sri Lanka
Mass media regulation
Social media
Child online safety laws | Online Safety Act (Sri Lanka) | [
"Technology"
] | 600 | [
"Computing and society",
"Social media"
] |
75,933,491 | https://en.wikipedia.org/wiki/Illosporiopsis%20christiansenii | Illosporiopsis christiansenii is a species of fungus that parasitizes lichen which is found in Europe and North America. It was first described as Hobsonia christiansenii.
Description
Illosporiopsis christiansenii can be identified by its bright pink conidia, approximately 0.5–1 mm across and 0.2–2 mm high, which contrast strongly with the lichen it parasitizes. It is only known to reproduce asexually.
Distribution
Illosporiopsis christiansenii is found throughout Europe and North America.
Habitat
Illosporiopsis christiansenii parasitizes lichen, including Parmelia, Physcia and Xanthoria.
References
Hypocreaceae
Fungus species
Lichenicolous fungi
Fungi described in 1986
Fungi of Europe
Fungi of North America | Illosporiopsis christiansenii | [
"Biology"
] | 170 | [
"Fungi",
"Fungus species"
] |
75,934,343 | https://en.wikipedia.org/wiki/Glen%E2%80%93Nye%20flow%20law | In theoretical glaciology and continuum mechanics, the Glen–Nye flow law, also referred to as Glen's flow law, is an empirically derived constitutive relation widely used as a model for the rheology of glacial ice. The Glen–Nye flow law treats ice as a purely viscous, incompressible, isotropic, non-Newtonian fluid, with a viscosity determined by a power law relation between strain rate and stress:
The effective strain rate (units of s−1) and effective stress (units of Pa) are related to the second principle invariants of their respective tensors. The parameters and are scalar constants which have been estimated through a combination of theory and measurements. The exponent is dimensionless, and the rate factor takes on the units Pa− s−1. The Glen–Nye flow law simplifies the viscous stress tensor to a single scalar value , the dynamic viscosity, which is determined by tensor invariants of the deviatoric stress tensor and the strain rate tensor .
Under the application of sustained force ice will flow as a fluid, and changes to the force applied will result in non-linear changes to the resulting flow. This fluid behavior of ice, which the Glen–Nye flow law is intended to represent, is accommodated within the solid ice by creep, and is a dominant mode of glacial ice flow.
Viscosity definition
The constitutive relation is developed as a generalized Newtonian fluid, where the deviatoric stress and strain tensors are related by a viscosity scalar:
where is the viscosity (units of Pa s), is the deviatoric stress tensor, and is the strain rate tensor. In some derivations, (units of Pa−1 s−1) is substituted.
This construction makes several assumptions:
Isotropy, as the single proportionality scalar is the same for all tensor components.
Incompressibility, as volumetric stress is ignored and only the deviatoric stress can do work.
That corresponding components of the two tensors are directly proportional to one another, i.e. . Theoretically, this assumption results from ignoring the third principle invariant of the tensors; physically, this means that the strain rate can only change along the same axes as the principal stresses.
While incompressibility is an accurate assumption for glacial ice, glacial ice can be anisotropic and in general the strain rate may respond perpendicularly to the principal stress.
With these assumptions, the stress and strain rate tensors here are symmetric and have a trace of zero, properties that allow their invariants and squares to be simplified from the general definitions.
The deviatoric stress tensor is related to an effective stress by its second principal invariant:
where Einstein notation implies summation over repeated indices.
The same is defined for an effective strain rate:
From this form, we can recognize that:
and
The viscosity is scalar and cannot be negative (a fluid cannot gain energy as it flows), so can be expressed in terms of the invariant effective stress and effective strain rate.
Here, the Glen–Nye flow law allows us to substitute for either or , and can be defined in terms of either the effective strain rate or effective stress alone:
where (units of Pa s) is sometimes substituted.
Parameter values
The Glen–Nye rheology model defines two parameters, and .
The rate factor has been found empirically to vary with temperature and is often modeled with an Arrhenius relation describing the temperature dependence of creep:
where is the activation energy, is the universal gas constant, and is the absolute temperature. The prefactor may be dependent on crystal structure, impurities, damage, or other qualities of the ice. Estimates of vary by orders of magnitude and can be derived as a single value from an estimated value for , or by comparing measurements of multiple real world glaciers and experiments, or treated as a scalar field inferred from observations by a numerical inversion of the momentum equation for ice flow at a specific location.
Viscous ice flow is an example of shear thinning, which corresponds to . Review of research using a variety of methods and field sites have found the range of plausible values to be around with the most commonly used assumption to be a constant . However, the value of is also stress dependent, and can reflect different microstructural mechanisms facilitating creep at different stress regimes.
Methods to improve estimations of these viscous parameters are an ongoing field of research.
Limitations
The use of the word "law" in referring to the Glen-Nye model of ice rheology may obscure the complexity of factors which determine the range of viscous ice flow parameter values even within a single glacier, as well as the significant assumptions and simplifications made by the model itself.
In particular, treatment of the ice as a fluid with bulk properties does not represent and may struggle to capture the cascade of mechanisms which allow the ice to deform at the grain scale in solid state. Glacial ice crystals grow on scales of millimeters up to 10 cm, and constant readjustment between grain structure and internal stress results in high variations in strain across the same length-scale as the crystals themselves. Additionally, individual ice crystals are not isotropic, and typically are not randomly oriented within the material fabric which undergoes dynamic recrystallization. Grain size and fabric orientation are known to influence the creep of glacial ice, but are dynamic properties which also evolve with the stress regime and are not simple to capture in a model.
The Glen-Nye flow law also does not render the full range of ice response to stress, including elastic deformation, fracture mechanics (i.e. crevasses), and transient phases of creep.
See also
Glaciology
Ice sheet dynamics
Rheology
Ice-sheet model
References
Glaciology
Continuum mechanics | Glen–Nye flow law | [
"Physics"
] | 1,198 | [
"Classical mechanics",
"Continuum mechanics"
] |
75,936,022 | https://en.wikipedia.org/wiki/Marie%20Lynn%20Miranda | Marie Lynn Miranda (born ) is an American economist, data scientist, and academic administrator. She became the tenth chancellor of the University of Illinois Chicago and a vice president of the University of Illinois System in July 2023. She previously served as provost and professor of applied computational mathematics and statistics at the University of Notre Dame. A self-taught toxicologist and environmental scientist, Miranda researches children's environmental health and geospatial health informatics.
Early life and education
Miranda was born in . She is the first member of her family to be born in the United States. In 1961, her parents and three brothers moved to South Bend, Indiana from Goa while her father, Constancio Miranda, was studying civil engineering. He was later a professor at the University of Detroit Mercy. She attended Catholic schools in Detroit. Miranda earned an A.B. in mathematics and economics, summa cum laude, from Duke University in 1985. She was inducted into Phi Beta Kappa at Duke University. While attending Duke University, she worked as a student manager for the Duke Blue Devils men's basketball under coach Mike Krzyzewski. Miranda earned an M.A. (1988) and a Ph.D. in economics from Harvard University. Her 1990 dissertation was titled, Essays on Land Management. Peter Timmer, Lawrence Goulder, and Jerry Green served on her doctoral committee.
Career in academia
Miranda joined the faculty at Duke University in 1990. She is a self-taught toxicologist and environmental scientist and joined Duke's integrated toxicology and environmental health program in 1999. Miranda was the founding director of the Children's Environmental Health Initiative (CEHI). For nine years, she was the director of undergraduate programs for the Nicholas School of the Environment. As a data scientist, her research focuses on geospatial health informatics. From 2012 to 2015, Miranda was the Samuel A. Graham dean of the school of natural resources and environment at University of Michigan. With a quantitative methods background, she was a professor of pediatrics and obstetrics and gynaecology at Michigan Medicine.
In 2019, she was elected a fellow of the American Association for the Advancement of Science.
Miranda was the Howard R. Hughes Provost and a professor of statistics at Rice University from 2015 to 2019.
From July 1, 2020, to December 31, 2021, Miranda was the Charles and Jill Fischer Provost of the University of Notre Dame. She succeeded Thomas G. Burish to become was the first woman and person of color to serve in the position. She was also a professor of applied computational mathematics and statistics at Notre Dame.
In July 2023, Miranda became the tenth chancellor of the University of Illinois Chicago (UIC). In that capacity, she is also a vice president of the University of Illinois System. She also serves as a faculty member in both the Department of Pediatrics and the Department of Mathematics, Statistics, and Computer Science.
Personal life
Miranda is married to Christopher Geron. They have three children, two English Setters, and roughly 500,000 honeybees.
See also
List of women in mathematics
References
Living people
Place of birth missing (living people)
Year of birth missing (living people)
American people of Goan descent
Duke University alumni
Duke University faculty
University of Michigan faculty
Harvard University alumni
Rice University faculty
University of Notre Dame faculty
University of Illinois Chicago faculty
Women data scientists
American data scientists
21st-century American women mathematicians
21st-century American mathematicians
American women statisticians
American toxicologists
Women toxicologists
American environmental scientists
American medical researchers
American women medical researchers
Fellows of the American Association for the Advancement of Science
American social scientists of Asian descent
American academics of Indian descent
American health professionals of Indian descent
1960s births
Women deans (academic)
American university and college faculty deans | Marie Lynn Miranda | [
"Environmental_science"
] | 758 | [
"American environmental scientists",
"Environmental scientists"
] |
75,937,036 | https://en.wikipedia.org/wiki/Berkelium%28II%29%20oxide | Berkelium(II) oxide is a binary inorganic compound of berkelium and oxygen with the chemical formula .
Physical properties
The compound is described to be a brittle gray solid.
References
Oxides
Berkelium compounds
Oxygen compounds | Berkelium(II) oxide | [
"Chemistry"
] | 47 | [
"Salts",
"Oxides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,937,421 | https://en.wikipedia.org/wiki/Models%20as%20Mediators | Models as Mediators: Perspectives on Natural and Social Science is a multi-author book edited by Mary S. Morgan and Margaret Morrison and published in 1999 by Cambridge University Press.
Synopsis
The volume looks at the working of models in the social and natural sciences, with a focus in economics and physics.
The book illustrate the concept of models as mediating between theory and the world and yet independent from both. It offers a historical and philosophical discussion of what models are and of what models do, with detailed examples written by the same editors and scholars such as Ursula Klein, Marcel Boumans, R.I.G. Hughes, Mauricio Suárez, Geert Reuten, Nancy Cartwright, Adrienne van den Boogard and Stephan Hartmann.
Content
Models and theories are related, so that an evolution in the perception of what a scientific theory is also chances the perception of what models are. The concept of scientific theory has moved from the 'received view' - whereby a theory can be seen as an axiomatic system to be dealt with in the context of the discipline of logic, to a new conception of theory as framed in therms of semantics, whereby models acquire a new prominence as 'fundamental unit of scientific theorizing, theories themselves being families of models'. Most of the examples in the book are quite articulated and pertinent to either physics or economics,
with one, offered by historian of science Ursula Klein, in Chemistry.
The introduction written by Margaret Morrison and Mary S. Morgan discusses the syntactic versus semantic view of theories and how these consider models. The second chapter by the same authors entitled 'Models as mediating instruments' — a key chapter in the economy of the volume, introduces the unifying theme of the work: the concept of models as mediators between theory and world. Models may represent 'some aspect of our theories about the world'.{rp|11}. While they may act as mediators between theory and world, they are situated outside the theory-world axis'.{rp|11}
We believe there is a significant connection between the autonomy of models and their ability to function as instruments. It is precisely because models are partially independent of both theories and the world that they have this autonomous component and so can be used as instrument of exploration in both domains.
The chapter also details what has been called a 'functionalist' articulation of the difference between models and theory, namely in four functions served by models: the first is how they are constructed deriving elements from one or more theories, other models, and the world. The second function is the use of models as instruments for the exploration and development of theory and or for the design of better experiments. The third is their use to 'represent' beyond what a theory alone can offer. The fourth function is the capacity of the model to enhance learning - though this function is also present in the preceding three steps. Morrison and Morgan emphasize that models can thus be regarded as 'technologies for investigation' — one learns by manipulating and playing with them. Models
have the quality of a technology — the power of the model only becomes apparent in the context of its use.
Chapter 3 by Margaret Morrison, entitled 'Models as autonomous agents', elaborates on the autonomy of models with example from physics. Chapter 4 'Built in justification' is from Marcel Boumans. Using examples from economics Boumans shows that models 'integrate a broader range of ingredients than only theory and data': these are theoretical notions, mathematical concepts and techniques, stylized facts, empirical data, policy views, analogies, metaphors.
Chapter 5 from R.I.G. Hughes, discusses how the development of computers and simulation changed the relation between models and theory. It was the use of computer simulation that permitted the Ising model to be accepted. In Chapter 6 by Ursula Klein chemical formulae as developed by Jöns Jacob Berzelius in 1813 are presented as 'paper tools' permitting representation and the construction of models. In Chapter 6 Mauricio Suárez discusses how an essential feature of models as mediators is to possibly replace the phenomenon itself in becoming the focus of scientific research, and illustrate this feature with an example from superconductivity in physics.
Chapter 8 from Geert Reuten, 'Knife edge caricature modelling: the case of Marx's reproduction schema' is a 'detailed historical reconstruction' or exegesis of Marxian economics, with little general theory of models. Chapter 9 from Nancy Cartwright 'Models and the limit of theory: quantum Hamiltonians and the BCS model of superconductivity' distinguishes what she call representative models that are accurate to the phenomena from more theory-internal models, models that bridge element of the theory with one another, and that are named interpretative models, especially in fields such as quantum mechanics, quantum electrodynamics, classical mechanics and classical electromagnetic theory. For example, an abstract concept such as force 'can only exist in particular mechanical models'.
Adrienne van den Boogard notes that 'the model is also a social and political device', and shows how institutions can be 'influenced (but were also conditioned by) the usage of different models and statistical techniques.' van den Boogard provides an illustration based on economic models and index numbers developed in the Netherlands. In discussing for example unemployment statistics:
Even the most simple-looking figure, i.e. absolute numbers, reflect an institutional structure, embody work of people (filling questionnaires) as consequence of which the actual figures represent a specific group of unemployed, namely those who found their job via the official employment offices.
For Stephan Hartmann empirical adequacy and logical consistency are not the only criteria of models acceptance. The story told by a model matters to its acceptability, and thus to its function and quality. The argument is developed in the final chapter of the volume entitled 'Models and stories in hadron physics'.
Reception
One review notes that while the title appears to promise a unified theory of models the chapters point instead to a universe of possible ways to characterize the nature and use of models. Acting as mediators, models are partly independent from both theory and world, and this independence, that ensures the versatility of 'models as autonomous agents', is also the reason why they resist an attempt to a unified 'theory of models'.
But the individual chapters make clear why Models as Mediators cannot possibly offer such a theory: the models dealt with in the book are so diverse and disparate that they cannot really be covered by a general description.
The 'functionalist' — rather than philosophical approach of the work, i.e. more about what a model does than what a model is, leaves several questions unanswered (or answered in different ways in different chapters). Furthermore, the examples are quite technical and detailed, not easy to read for the non initiated. Important epistemological questions left open concerns for example why individual models are constructed with
the particular degrees of independence from theory and experiment. Being focused on models in physics, chemistry and economics, the book leaves out biological models.
The book lays the basis for a research programme for studying models from the point of view of scientific practice providing 'a potential bridge between philosophical theorising and the more practice-oriented approach of STS'.
See also
Sociology of quantification
Frigg, R. and Hartman, S., Models in Science, Stanford Encyclopedia, 2006.
References
1999 non-fiction books
Philosophy of science
History of probability and statistics
Science and technology studies | Models as Mediators | [
"Mathematics",
"Technology"
] | 1,537 | [
"Probability and statistics",
"Science and technology studies",
"History of probability and statistics"
] |
75,938,447 | https://en.wikipedia.org/wiki/Vyatip%C4%81ta | In Indian astronomy and astrology, vyatipāta and vaidhṛti (or, vaidhṛta) are two moments in the regular motion of the sun and the moon in the zodiac characterized by their certain special relative positions. These terms are also used to denote two of the 27 Nityayoga-s: vyatipāta is the 17th nityayoga and vaidhṛti is the 27th nityayoga.
Definitions
Sūrysiddhānta defines vyatipāta and vaidhṛti as follows (Sūrysiddhānta Chapter IX Pātādhikāra verses 1 and 2):
When the sun and moon are upon the same side of either solstice, and when, the sum of their longitudes being a circle, they are of equal declination, it is styled vaidhṛta.
When the moon and sun are upon opposite sides of either solstice, and their minutes of declination are the same, it is vyatipāta, the sum of their longitudes being a half-circle.
The term pāta in the present context means literally "fall," and hence also either "fault, transgression," or " calamity." The term was probably first
applied to the moon's nodes, because they were the points of danger in her revolution, near which the sun or herself was liable to fall into the
jaws of Rāhu. Why the time when the sun and moon are equally distant from the equator should be looked upon as so especially unfortunate is not easy to discover. When the equal declinations are of opposite direction, the aspect is denominated vaidhṛta, or vaidhṛti. It has been noted above that it is the
name of the last nityayoga. The name of the other aspect (pāta), which occurs when the sun and moon are equally removed from the
equator upon the same side of it, is vyatipāta, which may be rendered "very excessive sin or calamity." This, too, is the name of one of the
nityayoga-s, but not of that one which occurs when the sum of longitudes of the sun and moon is 180 degrees.
The specification that the pāata-s take place when the sum of longitudes equals a circle or a half-circle respectively, or when the two luminaries are equally distant from either solstice, or either equinox, is not to be understood as exact: this would be the case if the moon had no motion in latitude; but owing to that motion, the equality of declinations, which is the main thing, occurs at a time somewhat removed from that of equality of distance from the equinoxes: the latter is called madhyapāta, "the mean occurrence of the pāta."
Chapter XI Pātādhikāra of Sūrysiddhānta is devoted entirely to a discussion on vyatipāta and vaidhṛti. Among other things, the chapter discusses the malignant aspects of the pāata-s, methods to find the longitude of the sun and moon when their declinations are equal, methods to determine the duration of the aspect, and the moment of its beginning and end, etc. According to Burgess: "Of all the chapters in the treatise, this is the one which has least interest and value."
Records of vyatīpāta-s in stone inscriptions
This term vyatīpāta appears in several stone inscriptions. The contexts of the inscriptions may be grants, donations to temples, records of death of war heroes, self-immolation of saints or women committing sati. A detailed study of these inscriptions has yielded valuable information about eclipses and other celestial events like planetary conjunctions.
See also
Nityayoga
References
Astrology
Hindu astronomy
Superstitions of India | Vyatipāta | [
"Astronomy"
] | 787 | [
"Astrology",
"History of astronomy"
] |
75,938,487 | https://en.wikipedia.org/wiki/Algorithmic%20problems%20on%20convex%20sets | Many problems in mathematical programming can be formulated as problems on convex sets or convex bodies. Six kinds of problems are particularly important: optimization, violation, validity, separation, membership and emptiness. Each of these problems has a strong (exact) variant, and a weak (approximate) variant.
In all problem descriptions, K denotes a compact and convex set in Rn.
Strong variants
The strong variants of the problems are:
Strong optimization problem (SOPT): given a vector c in Rn, find a vector y in K such that cTy ≥ cTx for all x in K, or assert that K is empty.
Strong violation problem (SVIOL): given a vector c in Rn and a number t, decide whether cTx ≤ t for all x in K, or find y in K such that cTy > t.
Strong validity problem (SVAL): given a vector c in Rn and a number t, decide whether cTx ≤ t for all x in K.
Strong nonemptyness problem (SNEMPT): Decide whether K is empty, and if not, find a point in K.
Strong separation problem (SSEP): given a vector y in Rn, decide whether y in K, and if not, find a hyperplane that separates y from K, that is, find a vector c in Rn such that cTy > cTx for all x in K.
Strong membership problem (SMEM): given a vector y in Rn, decide whether y in K.
Closely related to the problems on convex sets is the following problem on a convex function f: Rn → R:
Strong unconstrained convex function minimization (SUCFM): find a vector y in Rn such that f(y) ≤ f(x) for all x in Rn .
Trivial implications
From the definitions, it is clear that algorithms for some of the problems can be used to solve other problems in oracle-polynomial time:
An algorithm for SOPT can solve SVIOL, by checking whether cTy > t;
An algorithm for SVIOL solves SVAL trivially.
An algorithm for SVIOL can solve SNEMPT, by taking c=0 and t=-1.
An algorithm for SSEP solves SMEM trivially.
Examples
The solvability of a problem crucially depends on the nature of K and the way K it is represented. For example:
If K is represented by a set of some m linear inequalities, then SSEP (and hence SMEM) is trivial: given a vector y in Rn, we simply check if it satisfies all inequalities, and if not, return a violated inequality as the separating hyperplane. SOPT can be solved using linear programming, but it is not so trivial.
If K is represented as the convex hull of some m points, then SOPT (and hence SVIOL, SVAL and SNEMPT) is easy to solve by evaluating the objective on all vertices. SMEM requires to check whether there is a vector that is a convex combination of the vertices, which requires linear programming. SSEP also requires a certificate in case there is no solution.
If K is represented as the epigraph of some computable convex function, then SMEM is trivial; if a subgradient can be computed, then SSEP is easy too.
Weak variants
Each of the above problems has a weak variant, in which the answer is given only approximately. To define the approximation, we define the following operations on convex sets:
S(K,ε) is the ball of radius ε around K, defined as {x in Rn : |x-y| ≤ ε for some y in K}. Informally, a point in S(K,ε) is either in K or "almost" in K.
S(K,-ε) is the interior ε-ball of K, defined as {x in K : every y with |x-y| ≤ ε is in K}. Informally, a point in S(K,-ε) "deep inside" K.
Using these notions, the weak variants are:
Weak optimization problem (WOPT): given a vector c in Qn and a rational ε>0, either -
find a vector y in S(K,ε) such that cTy + ε ≥ cTx for all x in S(K,-ε), or -
assert that S(K,-ε) is empty.
Weak violation problem (WVIOL): given a vector c in Qn, a rational number t, and a rational ε>0, either -
assert that cTx ≤ t + ε for all x in S(K,-ε), or -
find a y in S(K,ε) such that cTy > t - ε.
Weak validity problem (WVAL): given a vector c in Qn, a rational number t, and a rational ε>0, either -
assert that cTx ≤ t+ε for all x in S(K,-ε), or -
assert that cTy ≥ t-ε for some y in S(K,ε).
Weak nonemptyness problem (WNEMPT): Given a rational ε>0, either -
assert that S(K,-ε) is empty, or -
find a point y in S(K,ε).
Weak separation problem (WSEP): given a vector y in Qn and a rational ε>0, either -
assert that y in S(K,ε), or -
find a vector c in Qn (with ||c||∞=1) such that cTy + ε > cTx for all x in S(K,-ε).
Weak membership problem (WMEM): given a vector y in Qn, and a rational ε>0, either -
assert that y in S(K,ε), or -
assert that y not in S(K,-ε).Closely related to the problems on convex sets is the following problem on a compact convex set K and a convex function f: Rn → R given by an approximate value oracle:
Weak constrained convex function minimization (WCCFM): given a rational ε>0, find a vector in S(K,ε) such that f(y) ≤ f(x) + ε for all x in S(K,-ε).
Trivial implications
Analogously to the strong variants, algorithms for some of the problems can be used to solve other problems in oracle-polynomial time:
An oracle for WOPT can solve WVIOL, by checking whether cTy + ε > t;
An oracle for WVIOL solves WVAL trivially.
An oracle for WVIOL can solve WNEMPT, by taking c=0 and t=-1.
An oracle for WSEP can be used to solve WMEM.
Stronger weak variants
Some of these weak variants can be slightly strengthened. For example, WVAL with inputs c, t' = t+ε/2 and ε' = ε/2 does one of the following:
assert that cTx ≤ t+ε for all x in S(K,-ε/2), or -
assert that cTy ≥ t for some y in S(K,ε/2).
Implications of weak variants
Besides these trivial implications, there are highly non-trivial implications, whose proof relies on the ellipsoid method. Some of these implications require additional information about the convex body K. In particular, besides the number of dimensions n, the following information may be needed:
A circumscribed radius R, which is the radius of a ball centered at the origin that contains K. The tuple (K;n,R) is called a circumscribed convex set.
An inscribed radius r, which is the radius of a ball contained in K in case K is nonempty. This r also provides a lower bound on the volume of K. The tuple (K;n,R,r) is called a well-bounded convex set.
An interior point a0, which is a point such that a ball of radius r around a0 is contained in K. The tuple (K;n,R,r,a0) is called a centered convex set.
The following can be done in oracle-polynomial time:
An oracle for WSEP, with a circumscribed radius R, can solve WVIOL. This algorithm uses the central-cut ellipsoid method. Another option is to use another method that uses simplices instead of ellipsoids.
An oracle for WVIOL, with a circumscribed radius R, can solve WOPT using binary search.
An oracle for WSEP, with a circumscribed radius R, can solve WOPT. This follows by transitivity from the implications WSEP→WVIOL and WVIOL→WOPT, but there is also a direct algorithm WSEP→WOPT using the sliding objective function technique.
An oracle for WMEM, with R and r and a0, can solve WVIOL. This was proved by Yudin and Nemirovskii in 1976, using the shallow-cut ellipsoid method.
An oracle for WMEM, with R and r and a0, can solve WOPT. This follows by transitivity from the implications WMEM→WVIOL and WVIOL→WOPT.
An oracle for WMEM, with R and r and a0, can solve WSEP. This follows by transitivity from the implications WMEM→WVIOL and WVIOL→WSEP. Interestingly, both steps require the ellipsoid method, and no direct algorithm WMEM→WSEP is known.
An oracle for WOPT can solve WCCFM.
An approximate value oracle for a convex function can be used to construct a WMEM oracle. Combining this with the implications WMEM→WVIOL and WVIOL→WOPT and WOPT→WCCFM implies that WCCFM on a centered convex body (K;n,R,r,a0) given by a WMEM oracle can be solved in polynomial time.
An oracle for WOPT, with r, can be used to found r and a0 such that S(a0,r') is contained in K.
The following implications use the polar set of K - defined as . Note that K**=K.
An oracle for WVAL on an 0-centered convex body (K; n,R,r,0) can solve WMEM on K*.
An oracle for WVIOL on an 0-centered convex body (K; n,R,r,0) can solve WSEP on K*.
An oracle for WOPT can solve WSEP without any further information. The proof uses polarity arguments.
An oracle for WVAL, with a circumscribed radius R, can solve WSEP. The proof uses polarity arguments.
Necessity of additional information
Some of the above implications provably do not work without the additional information.
An oracle for WMEM or even for SMEM, with R and r but without a0, cannot solve WVIOL in polytime, even for n=1 and r=1 and c=1 and ε=1. Proof. Note that with the given parameters, what we know about K is that K is contained in the interval [-R,R], and contains some interval of length 2r=2. Suppose an SMEM oracle answers "no" to the first R membership queries; this is a valid sequence of answers, since by the pigeonhole principle, there is an interval of length 2 that does not contain any querired point. Therefore, any algorithm solving WOPT needs more than R queries, so it is exponential in the encoding length of R.
Similarly, an algorithm for WMEM, with R and r but without a0, cannot solve WOPT.
An oracle for WVAL, with r and a0 but without R, cannot solve WVIOL.
An oracle for WVIOL, with r and a0 but without R, cannot solve WOPT and cannot solve WMEM.
An oracle for WMEM, with r and a0 but without R, cannot solve WSEP.
An oracle for WSEP, with r and a0 but without R, cannot solve WVAL.
An oracle for WSEP with r cannot be used to derive a0, and hence cannot be used to solve WOPT.
An oracle for WVIOL with r cannot be used to derive a0, and hence cannot be used to solve WOPT.
An oracle for WSEP with R cannot be used to derive r.
Geometric problems on convex bodies
Using the above basic problems, one can solve several geometric problems related to convex bodies. In particular, one can find an approximate John ellipsoid in oracle-polynomial time:
Given a well-bounded convex body (K; n, R, r) described by a WSEP oracle, one can find an ellipsoid E(A,a) such that . The algorithm uses the shallow-cut ellipsoid method. Note that, by the Lowner-John theorem, there exists an ellipsoid satisfying a stronger relation , but that theorem does not yield a polytime algorithm.
Given a well-bounded, centrally-symmetric convex body (K; n, R, r) described by a WSEP oracle, one can find an ellipsoid E(A,a) such that . Note that a theorem by Jordan proves that there exists an ellipsoid satisfying a stronger relation , but that theorem does not yield a polytime algorithm.
Given a well-bounded, convex body (K; n, R, r) given as the solution set of a system of linear inequalities, one can find an ellipsoid E(A,a) such that .
Given a well-bounded, centrally-symmetric convex body (K; n, R, r) given as the solution set of a system of linear inequalities, one can find an ellipsoid E(A,0) such that .
These results imply that it is possible to approximate any norm by an ellipsoidal norm. Specifically, suppose a norm N is given by a weak norm oracle: for every vector x in Qn and every rational ε>0, it returns a rational number r such that |N(x)-r|<ε. Suppose we also know a constant c1 that gives a lower bound on the ratio of N(x) to the Euclidean norm, Then we can compute in oracle-polynomial time a linear transformation T of Rn such that, for all x in Rn, .
It is also possible to approximate the diameter and the width of K:
Given a well-bounded convex body (K; n, R, r) described by a WSEP oracle, its diameter can be approximated by finding two points x,y in K, and a ball with radius R* containing K, such that .
Given a well-bounded convex body (K; n, R, r) described by a WSEP oracle, its width can be approximated by finding two parallel hyperplanes cTx=d1 and cTx=d2 that lie on two sides of K, and a ball with radius r* contained in K, such that
Some problems not yet solved (as of 1993) are whether it is possible to compute in polytime the volume, the center of gravity or the surface area of a convex body given by a separation oracle.
Problems on combinations of convex sets
Some binary operations on convex sets preserve the algorithmic properties of the various problems. In particular, given two convex sets K and L:
For the sum K+L, WOPT can be solved in polytime using WOPT oracles for K and L. The same holds for WVIOL, WSEP and WVAL. However, the same does not hold for WMEM, unless K and L are centered convex bodies.
For the union conv(K u L), the results are the same for the sum: WOPT, WVIOL, WSEP and WVAL (but not WMEM) can be solved in polytime using the respective oracles for K and L.
For the intersection K ח L, it may be impossible to compute the inner radius in polytime, so we need to know the inner radius in advance. With this knowledge, all five problems (WMEM, WOPT, WVIOL, WSEP and WVAL) can be solved in polytime using the respective oracles for K and L.
Given WSEP oracles for K and L, and a rational number r>0, it is possible in oracle-polynomial time to return either (a) an assertion that the intersection K ח L contains a ball with radius r, or (b) a vector c with size 1, and a number d, such that cTx ≤ d for all x in S(K,-ε) and cTx ≥ d for all x in S(L,-ε), where ε=9nr3(RK/rK + RL/rL). That is: either the intersection contains a ball, or there is a hyperplane almost-separating K from L.
From weak to strong oracles
In some cases, an oracle for a weak problem can be used to solve the corresponding strong problem.
General convex sets
An algorithm for WMEM, given circumscribed radius R and inscribe radius r and interior point a0, can solve the following slightly stronger membership problem (still weaker than SMEM): given a vector y in Qn, and a rational ε>0, either assert that y in S(K,ε), or assert that y not in K. The proof is elementary and uses a single call to the WMEM oracle.
Polyhedra
Suppose now that K is a polyhedron. Then, many oracles to weak problems can be used to solve the corresponding strong problems in oracle-polynomial time. The reductions require an upper bound on the representation complexity (facet complexity or vertex complexity) of the polyhedron:
An oracle for WNEMPT, for a full-dimensional polyhedron P with a bound on its representation complexity, can solve SNEMPT.
An oracle for WOPT, for a bounded full-dimensional polyhedron P with a bound on its representation complexity, can solve SOPT.
An oracle for WVIOL, for a bounded full-dimensional polyhedron P with a bound on its representation complexity, can solve SVIOL.
An oracle for WVAL, for a bounded full-dimensional polyhedron P with a bound on its representation complexity, can solve SVAL.
An oracle for WSEP, for a bounded full-dimensional polyhedron P with a bound on its representation complexity, can solve SSEP.
An oracle for WMEM, for a bounded full-dimensional polyhedron P with a bound on its representation complexity, given an interior point in P, can solve SMEM.
The proofs use results on simultaneous diophantine approximation.
Necessity of additional information
How essential is the additional information for the above reductions?
The assumption that P is full-dimensional is essential: if P is not full-dimensional, then the interior ball S(K,-ε) is empty. Therefore, any oracle for solving a weak problem cannot distinguish between P and the empty set.
The assumption that P is bounded can be relaxed: it is possible to define variants of the weak problems for polyhedra that may be unbounded, and prove reductions analogous to the above results.
For the implication WMEM→SMEM, the assumption that an interior point of P is given is essential. Proof: Suppose we have a polyhedron P with known vertex complexity 2n, and wish to decide whether 0 is in P. If we ask the WMEM oracle fewer than 2n queries, then the oracle can always answer "no", and it is possible that there exists a unit cube H with vertices whose coefficients are in {0,+1,-1}, that contains zero as a vertex, but does not contain any of the queried points. So it is possible that P=H and the answer is "yes", but it is also possible that P is the convex hull of all non-zero vertices of H and the answer is "no". Therefore, no polytime algorithm can solve SMEM.
Implications of strong variants
Using the previous results, it is possible to prove implications between strong variants. The following can be done in oracle-polynomial time for a well-described polyhedron - a polyhedron for which an upper bound on the representation complexity is known:
An oracle for SSEP can solve SNEMPT,
An oracle for each SSEP, SVIOL, SOPT can be used to solve the other two.
In the special case in which P is a cone, SVIOL for P is the same as SSEP for its polar cone P*; therefore, an SSEP oracle for P yields an SSEP algorithm for P*.
If we know in advance that P is nonempty, then the SSEP oracle can be replaced with a slightly weaker separation oracle: given a vector y in Qn, if y is not in P it finds a hyperplane that separates y from P (= a vector c in Rn such that cTy > cTx for all x in P), but if y is in P, it may still return a hyperplane - a vector c in R'''n such that cTy ≥ cTx for all x in P.
So SSEP, SVIOL and SOPT are all polynomial-time equivalent. This equivalence, in particular, implies Khachian's proof that linear programming can be solved in polynomial time, since when a polyhedron is given by explicit linear inequalities, a SSEP oracle is trivial to implement. Moreover, a basic optimal dual solution can also be found in polytime.
Note that the above theorems do not require an assumption of full-dimensionality or a lower bound on the volume.
Other reductions cannot be made without additional information:
If P is not full-dimensional, then SMEM cannot solve SSEP, SVIOL or SOPT.
If P is unbounded, then SVAL cannot solve SSEP, SVIOL or SOPT.
Extension to non-well-described convex sets
Jain extends one of the above theorems to convex sets that are not polyhedra and not well-described. He only requires a guarantee that the convex set contains at least one point (not necessarily a vertex) with a bounded representation length. He proves that, under this assumption, SNEMPT can be solved (a point in the convex set can be found) in polytime. Moreover, the representation length of the found point is at most P(n) times the given bound, where P is some polynomial function.
Geometric problems on polyhedra
Using the above basic problems, one can solve several geometric problems related to nonempty polytopes and polyhedra with a bound on the representation complexity, in oracle-polynomial time, given an oracle to SSEP, SVIOL or SOPT:
Find a vertex of P.
Given a vector c, find a vertex of P that maximizes cTx.
Given vectors c1,c2, find a vertex of P that maximizes c1Tx, and subject to this, maximizes c2Tx (lexicographic maximization).
Find the affine hull of P. This also implies finding the dimension of P, and a point in the relative interior of P.
Decide whether any two given vectors are vertices of P, and if so, whether they are adjacent.
Given a point in P, write it as a convex combination of at most n vertices of P (an algorithmic version of Carathéodory's theorem).
See also
Separation oracle - an algorithm for solving the (weak or strong) separation problem for some convex set K''.
References
Convex geometry
Mathematical optimization
Convex optimization | Algorithmic problems on convex sets | [
"Mathematics"
] | 5,009 | [
"Mathematical optimization",
"Mathematical analysis"
] |
75,938,839 | https://en.wikipedia.org/wiki/NGC%207625 | NGC 7625, or Arp 212, is a peculiar galaxy in the constellation of Pegasus. It was discovered on October 15, 1784, by William Herschel. In his New General Catalogue (1888), J. L. E. Dreyer described it as pretty bright, considerably small, round, with a suddenly much brighter middle. It is located at an estimated distance of from the Milky Way galaxy.
Halton Arp included NGC 7625 as object 212 in his Atlas of Peculiar Galaxies, indicating it displayed unexplained physical processes. In the Third Reference Catalogue of Bright Galaxies, NGC 7625 was assigned a morphological classification of SA(rs)a pec, which indicates a peculiar spiral galaxy (SA) with a transitional ring structure (rs) and tightly wound spiral arms (a). In 1981 it was designated a blue compact dwarf by T. X. Thaun and G. E. Martin on the basis of strong emission lines from ionized gas. A prominent visible feature is an open ring of dust lanes with an angular radius of about .
NGC 7625 displays indications of a recent interaction with another galaxy. Velocity measurements suggest the inner part of the galaxy is rotating in a different plane than the outer parts. The angle between these two planes increases with distance from the galactic center, reaching 50° at a radius of 6 kpc. Hence this may be a polar-ring galaxy, with the added gas accreted from the dwarf satellite galaxy UGC 12549. There is a large amount of gas and dust undergoing significant star formation, with emission of H-alpha concentrated at the core and in separate knots along exterior curved structures.
On October 28, 2023 type Ia supernova SN 2023vyl was discovered in this galaxy by ATLAS.
References
Further reading
Pegasus (constellation)
Peculiar galaxies
7625
12529
212
17841015
Discoveries by William Herschel
71133
71133
+03-59-038 | NGC 7625 | [
"Astronomy"
] | 394 | [
"Pegasus (constellation)",
"Constellations"
] |
75,940,974 | https://en.wikipedia.org/wiki/Blue%20City%20%28Warsaw%29 | Blue City is a postmodernist shopping centre in Warsaw, Poland, located at 179 Jerusalem Avenue within the district of Ochota. It was opened in 2004.
History
The investition, originally named the Reform Center, was first proposed in the late 1990s, by Sabri Bekdaş, owner of the Reform Company. It was envisioned as a 9-storey-tall shopping centre. It was proposed to also include there an amusement park themed around musician Michael Jackson. In 1997, Amnon Shiboleth, businessperson and Jackson's lawyer met with the representatives of the company, to discuss the proposition. While the idea of the theme park fell through, Shiboleth himself became interested in the investition, and bought 51% of ownership from the Reform Company. The building was designed by architect Vahap Toy. Due to issues between investors, the building remained unused for several years, and severely deteriorated over that time. Beginning in 2003, it was renovated and remodeled, and was opened on 31 March 2004. It became the biggest shopping centre in Poland at the time.
In 2018, in the shopping centre was opened the "miniature" IKEA store, with an area of 4,800 m2. It was the smallest store opened by the company worldwide, as part of the test of new business strategy. It was closed in 2021. In the same year, in Blue City was opened the Fit/One health club becoming the largest of its kind in Poland.
Characteristics
The Blue City shopping centre is located at 179 Jerusalem Avenue. The building was designed in the postmodernist style, and has the total area of 180,000 m2, of which 60,000 m2 is used by stores and services, while 19,000 m2 is an office space. It has 8 storeys, and its total height is 55 m. The shopping centre includes 220 stores.
On the opposite side of the street, at 148 Jerusalem Avenue, is located the Atrium Reduta shopping centre.
References
External links
2004 establishments in Poland
Ochota
Office buildings completed in 2004
Office buildings in Warsaw
Postmodern architecture
Shopping malls established in 2004
Shopping malls in Warsaw | Blue City (Warsaw) | [
"Engineering"
] | 430 | [
"Postmodern architecture",
"Architecture"
] |
75,941,194 | https://en.wikipedia.org/wiki/Pedro%20Ontaneda | Pedro Ontaneda Portal is a Peruvian-American mathematician specializing in topology and differential geometry. He is a distinguished professor at Binghamton University, a unit of the State University of New York.
Education and career
Ontaneda received his Ph.D. in 1994 from Stony Brook University (another unit of SUNY), advised by Lowell Jones.
Subsequently he taught at the Federal University of Pernambuco in Brazil.
He moved to Binghamton University in 2005.
Mathematical contributions
Ontaneda's work deals with the geometry and topology of aspherical spaces, with particular attention to the relationship between exotic structures and negative or non-positive curvature on manifolds.
Classical examples of Riemannian manifolds of negative curvature are given by real hyperbolic manifolds, or more generally by locally symmetric spaces of rank 1.
One of Ontaneda's most celebrated contributions is the construction of manifolds that admit negatively curved Riemannian metrics but do not admit locally symmetric ones.
More precisely, he showed that for any and for any there exists a closed Riemannian -manifold satisfying the following two properties:
All the sectional curvatures of are in .
is not homeomorphic to a locally symmetric space.
In particular, the fundamental group of is Gromov hyperbolic but not isomorphic to a uniform lattice in a Lie group of rank 1.
These manifolds are obtained via the Riemannian hyperbolization procedure developed by Ontaneda in a series of papers, which is a smooth version of the strict hyperbolization procedure introduced by Ruth Charney and Michael W. Davis.
The obstruction to being locally symmetric comes from the fact that Ontaneda's manifolds have nontrivial rational Pontryagin classes.
The restriction to dimension is necessary. Indeed, if a surface admits a negatively curved metric, then it admits one that is locally isometric to the real hyperbolic plane, as a consequence of the uniformization theorem. A similar statement holds for -manifolds thanks to the hyperbolization theorem.
Ontaneda also made a "remarkable" contribution to the classification of dynamical systems by constructing partially hyperbolic diffeomorphisms (a generalization of Anosov diffeomorphisms) on some simply connected manifolds of high dimension; see his 2015 paper.
Selected publications
F. T. Farrell, L. E. Jones, and P. Ontaneda (2007), "Negative curvature and exotic topology." In Surveys in Differential Geometry, Vol. XI, pp. 329–347, International Press, Somerville, MA.
F. Thomas Farrell and Pedro Ontaneda (2010), "On the topology of the space of negatively curved metrics." Journal of Differential Geometry 86, no. 2, pp. 273–301.
Andrey Gogolev, Pedro Ontaneda, and Federico Rodriguez Hertz (2015), "New partially hyperbolic dynamical systems I." Acta Mathematica 215, no. 2, pp. 363–393.
Pedro Ontaneda (2020), "Riemannian hyperbolization." Publ. Math. Inst. Hautes Études Sci. 131, pp. 1–72.
References
Year of birth missing (living people)
Living people
Place of birth missing (living people)
American people of Peruvian descent
American mathematicians
Peruvian mathematicians
Binghamton University faculty
Topologists
External links
Pedro Ontaneda's Author Profile on MathSciNet | Pedro Ontaneda | [
"Mathematics"
] | 701 | [
"Topologists",
"Topology"
] |
75,941,540 | https://en.wikipedia.org/wiki/Leonid%20N.%20Kartsev | Leonid Nikolaevich Kartsev (July 21, 1922 – April 13, 2013) was a Soviet major general. From 1953 to 1969 he was chief designer of the Uralvagonzavod (UVZ) tank design bureau in Nizhny Tagil, in Russia. He was responsible for the development of the T-55, T-62 and T-72.
Early life
Leonid Nikolaevich Kartsev was born in Skormovo, Gavrilovo-Posadsky District, Russia, on 21 July 1922. There is a T-62 memorial to Kartsev in Skormovo.
Uralvagonzavod tank design bureau
After engineering school Kartsev began working at UVZ in December 1949 under Aleksandr Morozov. This relationship has been described as "cordial" and Kartsev and Morozov both shared contempt for fellow tank engineer Josef Kotin of Kirov. Morozov left to lead the tank design bureau in Karkov in 1951, taking many of his engineers with him. Kartsev was promoted to Section 520 chief designer in 1953 days before the death of Joseph Stalin. After his promotion Kartsev was approached by the NKVD and told to hand over his jewish workers. Kartsev refused. The conflict was resolved following a coup led by Nikita Khrushchev that removed Lavrentiy Beria from power.
One of Kartsev's first projects as lead tank designer was to improve upon the T-54. Kartsev merged numerous incremental T-54 upgrade projects into one project called Obiekt 155. The result was the more successful T-55 which went into full production in January 1958.
The Military-Industrial Commission (VPK) authorized work on two alternative engines for a wartime T-64, a so-called "mobilization model" that could be produced more quickly and at half the cost.
GABTU sent a T-64A prototype with a team to Uralvagonzavod. Kartsev was to lead this team.
Kartsev was unsatisfied with the innovations of the T-64, and began instead a more comprehensive project to redesign the tank. Kartsev melded what he believed were the best aspects of the T-64A, Object 167, and an upgunned T-62.
During development the tank was code-named "Ural" after the Ural mountain region. Uralvagonzavod produced the first prototype with a T-62 turret, D-81 125-mm gun and V-45 engine in January 1968. Ob. 439 differed so greatly from the T-64 that it was redesignated as "Object 172".
Kartsev's defiance angered GABTU, which initially reprimanded him for his insubordination. However, after the tank proved indeed to possess potential as a less costly alternative to the T-64, Kartsev was allowed to continue work on his design. Politically motivated opposition continued to beset the tank throughout its development. Vagonka tank plant manager I.F. Krutyakov sought to subordinate Uralvagonzavod under Josef Kotin. Kartsev skillfully beat back this play for power, embarrassing Krutyakov in the process. Kartsev retired in August 1969, and was succeeded by Venediktov.
Decorations and awards
:
- 1966
- 1985
- 1944
:
- 2012
References
Bibliography
Communist Party of the Soviet Union members
Mechanical engineers
Soviet major generals
Recipients of the USSR State Prize
Recipients of the Medal of Zhukov
Recipients of the Medal "For Courage" (Russia)
Recipients of the Order "For Service to the Homeland in the Armed Forces of the USSR", 3rd class
Recipients of the Order of the Red Star
Recipients of the Order of Lenin
Recipients of the Order of Honour (Russia)
2013 deaths
1922 births
Tank designers
Weapon designers from the Soviet Union | Leonid N. Kartsev | [
"Engineering"
] | 803 | [
"Mechanical engineers",
"Mechanical engineering"
] |
75,941,872 | https://en.wikipedia.org/wiki/35%20Sextantis | 35 Sextantis (68 G. Sextantis; HD 92841; HR 4193), or simply 35 Sex, is a triple star system located in the equatorial constellation Sextans. The primary has an apparent magnitude of 6.09, making it barely visible to the naked eye, even under ideal conditions. The companion has an apparent magnitude of 7.01, making it readily visible in binoculars, but not to the naked eye. The system is located relatively far at a distance of approximately 700 light-years but it is drifting closer with a combined heliocentric radial velocity of .
The System
Hierarchy of orbits in the 35 Sextantis system
The system was first observed by Friedrich Georg Wilhelm von Struve in 1821. The separation between the A and B component was initially , but it has since decreased to 6.62". Thanks to this separation, the components 35 Sextantis can be distinguished using a telescope. Observations from Tokovinin & Gorynya (2007) revealed that the B component is a single-lined spectroscopic binary. The primary and secondary both take 23,302 years to orbit each other while the secondary and its close companion take 1,568 days to revolve around each other in a relatively eccentric orbit.
Physical characteristic
35 Sextantis A has a stellar classification of K2.5 III, indicating that it is an evolved K-type giant star that has exhausted hydrogen at its core and left the main sequence. 35 Sextantis B has a classification of K1 II-III, indicating that it is a hotter, more evolved K-type star that has the luminosity class intermediate between a bright giant and giant star. The primary has 2.45 times the mass of the Sun but it has expanded to 25.39 times the radius of the Sun. It radiates 240 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of , giving it an orange-hued when viewed in the night sky.
The secondary has a similar mass to the primary but it is smaller, having a radius 10.15 times that of the Sun. 35 Sextantis B radiates 57.2 times the luminosity of the Sun from its photosphere at an effective temperature of 5030 K. Both stars are metal deficient with iron abundances of [Fe/H] = −0.17 and [Fe/H] = −0.16 respectively. They spin modestly with projected rotational velocities of and 4.1 km/s. The close companion has a mass 58% that of the Sun's, suggesting that it may be a K-type main-sequence star.
References
Triple star systems
Spectroscopic binaries
K-type giants
Sextans
Sextantis, 35
Sextantis, 68
BD+05 02384
092841
052452
4193
00374350811 | 35 Sextantis | [
"Astronomy"
] | 602 | [
"Sextans",
"Constellations"
] |
75,943,248 | https://en.wikipedia.org/wiki/Nancy%20Dudney | Nancy Johnson Dudney is a retired American materials scientist, formerly a corporate fellow at the Oak Ridge National Laboratory. She is known for her research on electric batteries and energy storage.
Education and career
Dudney graduated from the College of William & Mary in 1975, with a bachelor's degree in chemistry. She earned a Ph.D. in ceramics in 1979 from the Massachusetts Institute of Technology, supervised by Robert L. Coble.
She joined the Oak Ridge National Laboratory in 1979 for postdoctoral research as a Wigner Fellow, and obtained a permanent staff researcher position there in 1981. She became a group leader in thin film ceramics in 1999, a senior research staff member in 2006, and a distinguished senior research staff member in 2010. She retired in 2021.
Recognition
Dudney was named as a fellow of the Electrochemical Society in 2013. UT–Battelle named her as a distinguished inventor in 2014, and Oak Ridge named her as a corporate fellow in 2015. She was elected to the National Academy of Engineering in 2022, "for contributions to the development of high-performance solid-state rechargeable batteries".
References
Year of birth missing (living people)
Living people
American materials scientists
American women engineers
Women materials scientists and engineers
College of William & Mary alumni
Massachusetts Institute of Technology alumni
Oak Ridge National Laboratory people
Members of the United States National Academy of Engineering | Nancy Dudney | [
"Materials_science",
"Technology"
] | 277 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
75,943,402 | https://en.wikipedia.org/wiki/Civ-Alert | Civ-Alert was the civil defense warning system in the U.S. state of Hawaii from 1960 to 1977. Civ-Alert was established in the wake of the tsunami generated by the 1960 Valdivia earthquake on the Chilean coast, which devastated Hilo. Unlike CONELRAD, the warning system in use in the mainland United States, Civ-Alert consisted of the transmission of civil defense information and instructions from a studio at state Civil Defense headquarters in Diamond Head on existing radio station frequencies; this was important, as no one radio station could cover the entire Hawaiian islands. The Civ-Alert system was a major improvement. It led to the redesign of emergency warnings in the mainland U.S. as a similar system, the Emergency Broadcast System (EBS). Civ-Alert was rebranded as EBS in May 1977.
History
The 1960 Valdivia earthquake, whose tsunami pummeled Hilo and led to the deaths of 65 people, exposed serious deficiencies in the island-wide warning system for natural disasters. The islands' existing warning system had been created in 1946, after a tsunami killed 150, and was described by scientists after Valdivia as a "horse and buggy" system that failed to account for advances in tsunami forecasting. Civil Defense responded by conducting a massive overhaul of its warning systems. It earmarked money to install 71 new sirens across the state, as well as $20,000 to establish Civ-Alert, a statewide system to broadcast civil defense information over all Hawaii radio stations. This system was conceived by Jock Fernhead at radio station KPOI.
Civ-Alert was approved for use in November 1960 and began full-time service on December 1, 1960. It was tested for the first time on January 3, 1961, and all Honolulu radio stations received the signal from Civil Defense in Diamond Head; they were equipped with warning lights to make them aware of impending Civ-Alert broadcasts. Civil Defense leaders soon sought authorization to have Civ-Alert supplant CONELRAD, the system used nationwide. CONELRAD depended on stations alternating time at one of two frequencies, 640 or 1240 kHz, on reduced power. This was not sufficient for use in Hawaii because a station operating at reduced power in CONELRAD mode might not be able to reach all of the islands. In July 1961, CONELRAD was formally discontinued in Hawaii.
Civ-Alert suffered issues in warning of a potential tsunami on December 20, 1962. It took ten minutes for Civ-Alert to activate, muddling an already confused warning setup. At one point, two Oahu radio stations were telling listeners it was safe to return to their homes while Civ-Alert continued the alert. Among the plans for improving the civil defense system was adding audible buzzers, in addition to the warning lights already in use, to radio studios to notify stations of incoming announcements. The system's performance was much improved in the wake of the 1965 Rat Islands earthquake in the Aleutian Islands; Civ-Alert went on the air three hours before the tidal wave was predicted to arrive on Oahu. The Honolulu Advertiser editorial board praised the broadcasting of director Roger Coryell, also a veteran newsman, and the network setup which also included DJ Hal Lewis as program director; a cartoon by Harry Lyons called the system "Hawaii's Paul Revere". By 1966, Civ-Alert had been expanded to provide notification to TV stations and movie theaters, while audio messages were additionally relayed on Muzak background music systems for broadcast in stores.
The success of Civ-Alert led to the scrapping of CONELRAD on the U.S. mainland. Federal officials investigated the Hawaii system and discontinued CONELRAD in 1963 in favor of the Emergency Broadcast System (EBS). The California state plan for the Emergency Alert System (EAS), successor to the EBS, credits Civ-Alert as "arguably the parent of the EBS and EAS". Hawaii was linked to the mainland EBS system in 1967, with five EBS stations on the four major islands. The statewide civil defense alert system continued to go by the Civ-Alert name until May 1977.
References
Emergency Alert System
Disaster preparedness in the United States
1960 establishments in Hawaii
1977 disestablishments in Hawaii
1968 introductions | Civ-Alert | [
"Technology"
] | 887 | [
"Warning systems",
"Emergency population warning systems"
] |
75,944,870 | https://en.wikipedia.org/wiki/Berkelium%28III%29%20nitride | Berkelium(III) nitride is a binary inorganic compound of berkelium and nitrogen with the chemical formula .
References
Nitrides
Berkelium compounds
Nitrogen compounds | Berkelium(III) nitride | [
"Chemistry"
] | 37 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,944,915 | https://en.wikipedia.org/wiki/Lian-Ping%20Wang | Lian-Ping Wang is a mechanical engineer and academic, most known for his work on computational fluid dynamics, turbulence, particle-laden flow, and immiscible multiphase flow, and their applications to industrial and atmospheric processes. He is the chair professor of mechanics and aerospace engineering at the Southern University of Science and Technology in China, professor of mechanical engineering, and joint professor of physical ocean science and engineering at University of Delaware.
Wang's research primarily focuses on fundamental physics in turbulent multiphase flows, utilizing computational fluid dynamics (CFD) modeling for intricate flows across various systems, including industrial, natural, and biological contexts. He developed traditional Navier-Stokes-based CFD methods and mesoscopic Boltzmann-equation based methods, like the lattice Boltzmann method and discrete unified gas kinetic scheme, as direct numerical simulation tools for complex turbulent and multiphase flows. He also devised numerical methods for studying complex fluid flow and transport in fuel cells and soil porous media, as well as the transport and retention of colloids and nanoparticles in the subsurface environment.
Wang is an elected Fellow of the American Society of Mechanical Engineers and the American Physical Society. He was named in the World's Top 2% Scientists list by Stanford University in 2023 and in the Most Cited Chinese Researchers list by Elsevier in 2021 and 2022. In addition, he is an associate editor of the Journal of Fluid Mechanics and Theoretical and Applied Mechanics Letters, as well as a member of the Editorial Advisory Board for the International Journal of Multiphase Flow.
Education
Wang received a bachelor's degree in mechanics in 1984 from Zhejiang University, before going to the US for PhD study, and subsequently obtained a PhD in mechanical engineering from Washington State University in 1990. During his PhD, he developed a theoretical model predicting the turbulent dispersion of sedimenting inertial particles, concurrently developing an empirical correlation for the integral time scale of fluid velocity observed by such particles, which came to be known as the Wang and Stock correction in multiphase flow literature.
Career and research
During his postdoctoral tenure with Martin Maxey, they authored a paper on particle-laden turbulent flows, utilizing DNS to reveal novel effects of small-scale turbulence structure on particle behavior. At Penn State, he conducted a study on Kolmogorov refined similarity using high-resolution DNS flows, measuring various quantities related to the intermittency and scaling dynamics of fine-scale turbulence.
In 1994, Wang joined the University of Delaware as an assistant professor of mechanical engineering, later becoming an associate professor in 2001 and professor in 2009. He serves as a chair professor of mechanics and aerospace engineering and director of the Center for Computational Science and Engineering at the Southern University of Science and Technology in China, professor of mechanical engineering, and joint professor of physical ocean science and engineering at the University of Delaware.
During the period of 1998 to 2013, Wang's research concentrated on the turbulent collision rate and collision efficiency of inertial particles, where he played a role in establishing a theoretical foundation for the collision kernel, generating rigorous collision rate data from DNS, providing an analytical parameterization of the turbulent collision kernel, and studying the impact of turbulent collision on warm rain initiation. In 2012, he investigated the transport and retention of colloids and nanoparticles in porous media, considering the effects of physicochemical interaction forces. Using the lattice Boltzmann method and Lagrangian particle tracking, he explored multiscale reversible particle retention near grain surfaces, with factors like flow speed, ionic strength, and surface characteristics influencing the retention rate.
In recent years, Wang developed a lattice Boltzmann-based particle-resolving simulation tool to study turbulence modulation by finite-size solid particles, revealing size-dependent characteristics. His group improved lattice Boltzmann method implementation for moving boundaries, enhancing numerical stability and computational efficiency, including the first DNS of turbulent pipe flow using the lattice Boltzmann method. He also developed lattice-Boltzmann models fully consistent with Navier-Stokes equations, such as the use of 2D rectangular or 3D cuboid lattices, and introduced a new D3Q27 lattice Boltzmann model enabling mesoscopic computation of local fluid vorticity, derived through an inverse design approach using hydrodynamic equations. Wang further applied the particle-resolving simulation tool to study the enhancement of particle drag in a turbulent background flow and dynamics of non-spherical particles.
Awards and honors
1998 – Francis Alison Young Scholars Award, University of Delaware
2006 – Distinguished Overseas Young Investigator Award, National Natural Science Foundation of China
2011 – Fellow, American Physical Society
2016 – Fellow, American Society of Mechanical Engineers
2016-2017 – Invitation Fellow, Japan Society for the Promotion of Science
2021, 2022 – Most Cited Chinese Researchers, Elsevier
2022 – Best Mechanical and Aerospace Engineering Scientists in China by Research.com
Selected articles
Wang, L. P., & Maxey, M. R. (1993). Settling velocity and concentration distribution of heavy particles in homogeneous isotropic turbulence. Journal of fluid mechanics, 256, 27–68.
Wang, L. P., & Stock, D. E. (1993). Dispersion of heavy particles by turbulent motion. Journal of Atmospheric Sciences, 50(13), 1897–1913.
Wang, L. P., Wexler, A. S., & Zhou, Y. (2000). Statistical mechanical description and modelling of turbulent collision of inertial particles. Journal of Fluid Mechanics, 415, 117–153.
Devenish, B. J., Bartello, P., Brenguier, J. L., Collins, L. R., Grabowski, W. W., IJzermans, R. H. A., ... & Warhaft, Z. (2012). Droplet growth in warm turbulent clouds. Quarterly Journal of the Royal Meteorological Society, 138(667), 1401–1429.
Grabowski, W. W., & Wang, L. P. (2013). Growth of cloud droplets in a turbulent environment. Annual review of fluid mechanics, 45, 293–324.
Peng,C., Ayala, O.M., & Wang, L. P. (2019). A direct numerical investigation of two-way interactions in a particle-laden turbulent channel flow, Journal of fluid mechanics, 875, 1096–1144.
Zhang, C., Guo, Z., & Wang, L. P. (2023). A thermodynamically consistent diffuse interface model for multi-component two-phase flow with partial miscibility. Computers & Mathematics with Applications, 150, 22–36.
References
External links
Biography at the Southern University of Science and Technology
Mechanical engineers
Zhejiang University alumni
Washington State University alumni
Academic staff of the Southern University of Science and Technology
University of Delaware faculty
Fellows of the American Society of Mechanical Engineers
Fellows of the American Physical Society
Year of birth missing (living people)
Living people | Lian-Ping Wang | [
"Engineering"
] | 1,440 | [
"Mechanical engineers",
"Mechanical engineering"
] |
75,946,920 | https://en.wikipedia.org/wiki/Laurylamine%20dipropylenediamine | Laurylamine Dipropylenediamine (DPTA) is an organic compound in the class of dodecylamines. It is a colourless liquid although commercial samples can appear yellow and exhibit an amine-like odour.
DPTA is a widely applied ingredient in many products, such as in surfactants, antimicrobials, preservatives, emulsifiers, corrosion inhibitors, chilling liquids, antistatics (e.g., in hair products), and dispersing agents.
In 2022, the EU decided upon not approving DPTA as an existing active substance for use in biocidal products of product-type 8, wood preservatives, due to the unacceptable risks for human health, and not having suitable risk mitigation measures.
References
Tertiary amines
Amines | Laurylamine dipropylenediamine | [
"Chemistry"
] | 173 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
75,946,935 | https://en.wikipedia.org/wiki/Berkelium%28III%29%20phosphide | Berkelium(III) phosphide is a binary inorganic compound of berkelium and phosphorus with the chemical formula .
Preparation
Berkelium(III) phosphide can be prepared by reacting berkelium with an excess of phosphorus at 540 °C:
Properties
Berkelium(III) phosphide crystallises in the cubic crystal system of the sodium chloride type. Its lattice constant of 5.669 Å.
References
Phosphides
Berkelium compounds
Phosphorus compounds | Berkelium(III) phosphide | [
"Chemistry"
] | 102 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,948,469 | https://en.wikipedia.org/wiki/U%20Pegasi | U Pegasi is a binary star system in the constellation of Pegasus, abbreviated U Peg. The pair form an eclipsing binary with a combined peak apparent visual magnitude of 9.23, which is far too faint to be visible to the naked eye. During the primary eclipse the magnitude decreases to 10.07, while the secondary eclipse only drops to magnitude 9.73. This system is located at a distance of approximately 596 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of around −28.5 km/s.
The variable luminosity of this system was discovered by S. C. Chandler in 1895. He found it to have a continuously varying light curve with a period of . Observing the star photometrically, in 1898 E. C. Pickering and O. Wendell determined a longer period of . H. Shapley published orbital measures for this eclipsing binary in 1913, estimating their relative luminosities and radii. It was determined to be a variable of the W Ursae Majoris type, and in 1945 the orbital period was shown to vary over time.
Properties
This is a double-lined spectroscopic binary star system with an orbital period of . Their orbital separation is just . The inclination of the orbital plane is at an angle of 76.1° to the plane of the sky from the Earth, so the components are seen to eclipse each other during an orbit. The deeper eclipse occurs when the cooler secondary overlaps the primary star. They belong to the W sub-class of W UMa eclipsing variables.
The larger member of this system is a G-type main-sequence star with a stellar classification of G2 V. The primary has a larger mass and radius than the Sun, while the secondary component is significantly smaller and less massive. The pair are in over-contact by about 14.9%, which allows a considerable amount of energy transfer between the two stars. As a consequence, the two components show similar effective temperatures and spectral classes. The cooler component displays a significant level of star spot activity that causes the light curve to vary anomalously over time. The system has an X-ray luminosity of .
The long term change in the orbital period may be explained by mass transfer between the components, with the matter streaming from the more massive to the less massive star. The overall period change indicates this mass transfer is occurring at an average rate of ·yr−1. Periodicity in the change rate suggests there may be a third orbiting component in the system with a period of . If so, it would need to have a mass of at least , which is high enough to be a star.
References
Further reading
G-type main-sequence stars
W Ursae Majoris variables
Astronomical X-ray sources
Pegasus (constellation)
Durchmusterung objects
093174 | U Pegasi | [
"Astronomy"
] | 589 | [
"Astronomical X-ray sources",
"Astronomical objects",
"Pegasus (constellation)",
"Constellations"
] |
75,949,002 | https://en.wikipedia.org/wiki/Zometool | Zometool is a construction set toy that had been created by a collaboration of Steve Baer (the creator of Zome architecture), artist Clark Richert, Paul Hildebrandt (the present CEO of Zometool), and co-inventor Marc Pelletier. It is manufactured by Zometool, Inc. According to the company, Zometool was primarily designed for kids. Zometool has also been used in other fields including mathematics and physics. For example, aperiodic tilings such as Penrose tilings can be modeled using Zometool. The learning tool was designed by inventor-designer Steve Baer, his wife Holly and others.
The Zometool plastic construction set toy is produced by a privately owned company of the same name, based outside of Longmont, Colorado, and which evolved out of Baer's company ZomeWorks. Its elements consist of small connector nodes and struts of various colors. The overall shape of a connector node is that of a non-uniform small rhombicosidodecahedron with each face replaced by a small hole. The ends of the struts are designed to fit in the holes of the connector nodes, allowing for syntheses of a variety of structures. The idea of shape-coding the three types of struts was developed by Marc Pelletier and Paul Hildebrandt. To create the "balls," or nodes, Pelletier and Hildebrandt invented a system of 62 hydraulic pins that came together to form a mold. The first connector node emerged from their mold on April 1, 1992.
In the years since 1992, Zometool has extended its product line, though the basic design of the connector node has not changed so all parts to date are compatible with each-other. From 1992 until 2000, Zometool produced kits with connector nodes and blue, yellow, and red struts. In 2000, Zometool introduced green struts, prompted by French architect Fabien Vienne, which can be used to construct the regular tetrahedron and octahedron. In 2003, Zometool changed the style of the struts slightly. The struts "with clicks" have a different surface texture and they also have longer nibs which allow for a more robust connection between connector node and strut.
Characteristics
The color of a Zometool strut is associated with its cross section and also with the shape of the hole of the connector node in which it fits. Each blue strut has a rectangular cross section, each yellow strut has a triangular cross section, and each red strut has a pentagonal cross section. The cross section of a green strut is a rhombus of √2 aspect ratio, but as the connector nodes do not include holes at the required positions, the green struts instead fit into any of the 12 pentagonal holes with 5 possible orientations per hole, 60 possible orientations in all; using them is not as straightforward as the other struts.
At their midpoints, each of the yellow and red struts has a twist where the cross-sectional shape reverses. This design feature forces the connector nodes on the ends of the strut to have the same orientation. Similarly, the cross section of the blue strut is a non-square rectangle, again ensuring that the two nodes on the ends have the same orientation. Instead of a twist, the green struts have two bends which allow them to fit into the pentagonal holes of the connector node which are at a slight offset from the strut's axis.[citation needed]
Among other places, the word zome comes from the term zone. The zome system allows no more than 61 zones. The cross-sectional shapes correspond to colors, and in turn these correspond to zone colors. Hence the zome system has 15 blue zones, 10 yellow zones, 6 red zones, and 30 green zones. Two shapes are associated with blue. The blue struts with a rectangular cross section are designed to lie in the same zones as the blue struts, but they are half the length of a blue strut; hence these struts are often called "half-blue" (and were originally made in a light blue color). The blue-green struts with a rhombic cross section lie in the same zones as the green struts, but they are designed so that the ratio of a rhombic blue-green strut to a blue strut is 1:1 (as opposed to the green strut's √2:1). Due to this length ratio, the blue-green struts that have a rhombic cross section do not mathematically belong to the zome system.[citation needed]
Mathematics of Zometools
The strut lengths follow a mathematical pattern: For any color, there exists lengths such that they increase by a constant factor of approximately 1.618, a number that is yield of what is called the “golden ratio" which is represented by Greek letter phi ( or ). The golden ratio is a ratio such that the sum of two quantities is equal to the ratio of the same quantities, based on the largest value of the two numbers.
Thus,
An application of the golden ratio for the zome system is that for each color,
there exists a length such that a long strut length equals the length of a medium strut connected to a short strut.
In other words, the length of the long strut equals the sum of the medium strut length and the a short strut length.
Definition
A zome is defined in terms of the vector space , equipped with the standard inner product, also known as 3-dimensional Euclidean space.
Let denote the golden ratio and let denote the symmetry group of the configuration of vectors , , and . The group , an example of a Coxeter group, is known as the icosahedral group because it is the symmetry group of a regular icosahedron having these vectors as its vertices. The subgroup of consisting of the elements with determinant 1 (i.e. the rotations) is isomorphic to .
Define the "standard blue vectors" as the -orbit of the vector . Define the "standard yellow vectors" as the -orbit of the vector . Define the "standard red vectors" as the -orbit of the vector . A "strut" of the zome system is any vector which can be obtained from the standard vectors described above by scaling by any power , where is an integer. A "node" of the zome system is any element of the subgroup of generated by the struts. Finally, the "zome system" is the set of all pairs , where is a set of nodes and is a set of pairs such that and are in and the difference is a strut.
There are then 30, 20, and 12 standard vectors having the colors blue, yellow, and red, respectively. Correspondingly, the stabilizer subgroup of a blue, yellow, or red strut is isomorphic to the cyclic group of order 2, 3, or 5, respectively. Hence, one may also describe the blue, yellow, and red struts as "rectangular", "triangular", and "pentagonal", respectively.
The zome system may be extended by adjoining green vectors. The "standard green vectors" comprise the -orbit of the vector and a "green strut" as any vector which can be obtained by scaling a standard green vector by any integral power . As above, one may check that there are =60 standard green vectors. One may then enhance the zome system by including these green struts. Doing this does not affect the set of nodes.
The abstract zome system defined above is significant because of the following fact: Every connected zome model has a faithful image in the zome system. The converse of this fact is only partially true, but this is due only to the laws of physics. For example, the radius of a zometool node is positive (as opposed to a node being a single point mathematically), so one cannot make a zometool model where two nodes are separated by an arbitrarily small, prescribed distance. Similarly, only a finite number of lengths of struts will ever be manufactured, and a green strut cannot be placed directly adjacent to a red strut or another green strut with which it shares the same hole (even though they are mathematically distinct).
As a modeling system
The zome system is especially useful for modeling 1-dimensional skeletons of highly symmetric objects in 3- and 4-dimensional Euclidean space. The most prominent among these are the five Platonic Solids, and the 4-dimensional polytopes related to the 120-cell and the 600-cell. However, many other mathematical objects may be modeled using the zome system, including:
Three of the four Kepler-Poinsot polyhedra
Regular polyhedral compounds
Regular 4-dimensional polytopes and some compounds
Many stellations of the rhombic triacontahedron
Many stellations of the regular icosahedron
Zonohedra, especially the rhombic enneacontahedron and rhombic triacontahedron
Hypercubes in dimensions 61 or fewer
Most uniform polyhedra (a major exception being those formed using the snub operation)
Many uniform 4-polytopes
Thorold Gosset's exceptional semiregular polytopes in 6, 7, and 8 dimensions
Some Johnson solids
Desargues configuration
Two of the Catalan solids
Classical and exceptional root systems
Triality (from Lie theory)
The uses of zome are not restricted to pure mathematics. Other uses include the study of engineering problems, especially steel-truss structures, the study of some molecular, nanotube, and viral structures, and to make soap film surfaces.
References
Further reading
Steve Baer. Zome Primer. Zomeworks Corporation, 1970.
David Booth. The New Zome Primer in Fivefold Symmetry, István Hargittai (editor). World Scientific Publishing Company, 1992.
George Hart, Four-Dimensional Polytope Projection Barn Raisings. Proceedings, Sixth International Conference of the Society of Art, Math, and Architecture, Texas A&M University. May 2007.
George Hart and Henri Picciotto. Zome Geometry: Hands-on Learning with Zome Models. Key Curriculum Press, 2001. .
Paul R. Hildebrandt & Marc G. Pelletier (1985). "Geometric Modeling Kit and Method of Making Same". United States Patent No. 4,701,131.
Paul Hildebrandt. Zome-inspired Sculpture. Proceedings, Bridges London: Connections between Mathematics, Art, and Music, Reza Sarhangi and John Sharp (editors). (2006) 335–342.
David A. Richter. Two results concerning the Zome model of the 600-cell. Proceedings, Renaissance Banff: Mathematical Connections between Mathematics, Art, and Music, Robert Moody and Reza Sarhangi (editors). (2005) 419–426.
David A. Richter and Scott Vorthmann. Green Quaternions, Tenacious Symmetry, and Octahedral Zome. Proceedings, Bridges London: Connections between Mathematics, Art, and Music, Reza Sarhangi and John Sharp (editors). (2006) 429–436.
Steven F. Rogers & Paul R. Hildebrandt (2002) "Connections for Geometric Modeling Kit". United States Patent No. 6,840,699 B2.
External links
Zome Geometry by George W. Hart and Henri Picciotto.
Zometool - Manufacturer's site.
Japan Zome Club (in Japanese)
Software
vZome
Construction toys
Educational toys
Mathematical tools | Zometool | [
"Mathematics",
"Technology"
] | 2,441 | [
"Applied mathematics",
"Mathematical tools",
"History of computing",
"nan"
] |
75,949,013 | https://en.wikipedia.org/wiki/Hawking%27s%20time%20traveller%20party | On 28 June 2009, British astrophysicist Stephen Hawking hosted a party for time travellers in the University of Cambridge. The physicist arranged for balloons, champagne, and nibbles for his guests, but did not send out the invitations until the following day, after the party was over.
The party was held at Gonville and Caius College on Trinity Street (52° 12' 21" N, 0° 7' 4.7" E) at 12:00 UT on 28 June 2009. In preparing for the event, Hawking said he hoped that copies of the invitation might survive for thousands of years, and that "one day someone living in the future will find the information and use a wormhole time machine to come back to my party, proving that time travel will one day be possible".
Invitations say that the reader is "cordially invited to a reception for Time Travellers" and that no RSVP is required.
Hawking waited in the room for a few hours before leaving, and no visitors arrived. He regarded the event as "experimental evidence that time travel is not possible".
References
Video
Stephen Hawking – Time Traveller's Party on YouTube
Time travel
Stephen Hawking
Parties
Physics experiments
June 2009 events in the United Kingdom
2009 in science
History of the University of Cambridge | Hawking's time traveller party | [
"Physics"
] | 265 | [
"Physics experiments",
"Time",
"Time travel",
"Physical quantities",
"Experimental physics",
"Spacetime"
] |
75,951,733 | https://en.wikipedia.org/wiki/Della%20Roy | Della Marie Martin Roy (1926–2021) was an American materials scientist who worked for more than 50 years at Pennsylvania State University. She was "an international leader in the field of cement and concrete research", including the reduction of greenhouse gas emissions from cement production; she was also known for her work on radioactive waste disposal, on the industrial uses of coal combustion products obtained as waste from other processes, on methods for converting coral into hydroxyapatite while preserving its porous structure, and on applications of converted coral in medical implants.
Early life and education
Della Marie Martin was born on November 3, 1926, in Merrill, Oregon. She completed high school at age 16, and majored in chemistry at the University of Oregon, where she graduated phi beta kappa in 1947.
Next, she traveled to Pennsylvania State University for graduate study in mineralogy, working there under the supervision of Elburt F. Osborn. As a graduate student, she shared an office with Indian-born physicist Rustum Roy; they married in 1948. They moved to India but returned to Penn State in 1950. Rustum Roy took a faculty position there while Della Roy continued her graduate program, completing her Ph.D. in 1952.
Career and later life
After earning a doctorate, Roy stated at Pennsylvania State University as a faculty member. She became a full professor in 1975, and retired as professor emerita in 2012 after more than 50 years at the university. In her retirement, she took a second position as research professor at Arizona State University, with a part-time appointment shared jointly between the university's School of Sustainable Engineering and the Built Environment and its School of Mechanical Aerospace, Chemical and Materials.
Roy and fellow Penn State faculty member Kathleen Mourant founded the journal Cement and Concrete Research in 1971; Roy remained its editor-in-chief until 2005.
Recognition
The American Ceramic Society named her as a Distinguished Life Fellow and Member; she was the 1982 recipient of the society's Jeppson Medal, the 1987 recipient of the L. E. Copeland Award of the society's Cements Division, the 2004 recipient of the society's Bleininger Award, and the namesake of the society's Della Roy Lecturer Award, given annually since 2000.
Her work on the use of coral in bone implants was awarded by an inaugural Golden Goose Award of the US Congress in 2012. She was also an elected member of the World Academy of Ceramics (its first woman member, elected in 1991) and an honorary member of the Institute for Concrete Technology (elected in 1987).
She was elected to the National Academy of Engineering in 1987, cited "for internationally recognized contributions to applied science and engineering of cement and concrete". She was its first female material scientist and the first women from Penn State elected to the academy.
Dellaite, a rare naturally-occurring mineral, was named after her in 1965. It is a calcium silicate hydrate (in the same family of compounds used for Portland cement), with the chemical formula Ca6(Si2O7)(SiO4)(OH)2, discovered in metamorphosed Scotland limestone, and synthesized in the laboratory by Roy.
Selected publications
In Memorial Tributes: National Academy of Engineering, Susan Trolier-McKinstry identifies the following as "among the most important" of Roy's publications, which numbered over 400 in total:
As well, she was coauthor of two books:
References
1926 births
2021 deaths
People from Klamath County, Oregon
American materials scientists
American women engineers
Women materials scientists and engineers
University of Oregon alumni
Pennsylvania State University alumni
Pennsylvania State University faculty
Arizona State University faculty
Members of the United States National Academy of Engineering | Della Roy | [
"Materials_science",
"Technology"
] | 749 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
75,952,518 | https://en.wikipedia.org/wiki/NanoACE | NanoACE is a technology demonstration CubeSat by Tyvak Nano-Satellite Systems to validate their communications, navigation, guidance, and software technology. NanoACE was launched onboard a Soyuz-2.1a Fregat-M, on July 14, 2017, along with Russian Earth imaging satellite Kanopus-V-IK and 71 other CubeSats.
The satellite has two Infrared and two visible light cameras. It can maneuver via its cold gas propulsion system.
References
CubeSats
Satellites
Satellites in low Earth orbit
Spaceflight
2017 in spaceflight | NanoACE | [
"Astronomy"
] | 111 | [
"Satellites",
"Spaceflight",
"Outer space"
] |
75,954,090 | https://en.wikipedia.org/wiki/Charles%20Babbage%27s%20Saturday%20night%20soir%C3%A9es | Charles Babbage's Saturday night soirées were gatherings held by the mathematician and inventor Charles Babbage at his home in Dorset Street, Marylebone, London from 1828 and into the 1840s. The soirées were attended by the cultural elite of the time.
Scientific soirées
Babbage left England when his wife and father died in 1827. On his return in 1828, now in possession of a considerable inheritance, he began to host Saturday evening parties. The science historian James A. Secord describes the parties as "scientific soirées". Secord writes that Babbage imported the idea from France, and once established, such soirées "became one of the chief ways in which scientific discussion could take place on a more sustained basis within polite society."
In her autobiography, the English writer and sociologist Harriet Martineau wrote: "All were eager to go to his glorious soirées and I always thought he appeared to great advantage as a host. His patience in explaining his machine in those days was really exemplary."
According to biographers Bruce Collier and James H. MacLachlan, "Babbage was a bon vivant with a love of dining out and socialising. He sparkled as a host and raconteur. His Saturday soirées were glittering events attended by the social and intellectual elite of London."
Guests
Hundreds of prominent people attended the soirées, including Ada Lovelace, Lady Byron, Arthur Wellesley, 1st Duke of Wellington, Charles Darwin and Emma Darwin, Charles Dickens, Michael Faraday, Sophia Elizabeth De Morgan, Mary Somerville, Harriet Martineau, photographic inventor Henry Fox Talbot, the actor William Macready, the composer Felix Mendelssohn, the historian Thomas Babington Macaulay, telegraph inventor Charles Wheatstone, the French philosopher Alexis de Tocqueville, geologist Charles Lyell and his wife Mary Lyell, Mary's sister Frances, the Belgian ambassador Sylvain Van de Weyer, electrical inventor Andrew Crosse and many others. According to C. R. Keeler, up to 200-300 people might attend one evening event.
Attractions
A demo of Babbage's unfinished Difference engine was on display for guests at some of the gatherings. He also displayed a mechanical dancer. In her autobiography, Harriet Martineau describes Babbage's disappointment at his guests being more interested in this dancing doll - a toy - than in his demo of a computing machine.
Influence
Ada Lovelace (then Ada Byron) first met Charles Babbage when her mother took her to one of his soirées on 5 June 1832, and the meeting led to a lifelong friendship and collaboration, culminating in Lovelace's notes on the Analytical engine.
References
Charles Babbage
Saturday
Meetings
19th century in London
19th century in science
Salon-holders
History of computer science
History of science | Charles Babbage's Saturday night soirées | [
"Technology"
] | 582 | [
"History of science",
"History of computer science",
"Computer science",
"History of science and technology",
"History of computing"
] |
75,955,097 | https://en.wikipedia.org/wiki/Stereum%20fasciatum | Stereum fasciatum is a basidiomycete crust fungus, which means it does not have the traditional mushroom gills nor stem, but rather grows flat or with shelf-like protrusions on wood. The spores are produced on basidia, just like the gilled mushrooms, but instead of gills, the hymenophore (spore bearing surface) directly houses the reproductive parts. In North America S. fasciatum was long thought to be S. ostrea, but the recent accessibility to DNA sequencing has revealed that the two are distinct, and that S. ostrea is native to Indonesia and is not found in North America.
Description
Stereum fasciatum grows in a fan-like shape with a broad base, and an upper surface that is covered in tufts of upright hairs. The overall shape, like most Stereum species, is fan or oyster-like, spreading outwards from the attachment to the wooden substrate. Unlike some similar species, when the fertile surface is bruised, it does not stain yellow.
Similar species
The typical Stereum pore-less undersurface, will separate it from similar looking polypores such as turkey tails (Trametes), and thin fruiting bodies growing shelf like will separate it from most other crusts. The distinguishing features of Stereum fasciatum is the combination of the non-yellowing undersurface, broad base attachment, and the upright hairs. To see the upright hairs, a hand lens may be needed. A common way to examine the hairs is to fold a specimen in half, with the undersurface touching and splitting the hairy upper surface, and then examining the split section hairs to see if they stand up straight or are felted.
Stereum subtomentosum is a similar species, also having upright hairs and a broader attachment, but it stains yellow, which S. fasciatum does not.
Stereum lobatum is another yellowing species, but it also usually has a narrower attachment to the substrate and felted hairs instead of upright (use a hand lens).
Stereum complicatum is usually smaller, and is brighter and more consistent orange.
Stereum hirsutum can look quite similar, but is more orange and smaller.
Taxonomy
It was first described in 1822 by Schweinitz as Thelephora fasciata, but in 1838 was transferred by Elias Fries to the genus, Stereum, giving the name Stereum fasciatum.
External links
Stereum fasciatum images & occurrence data
References
Stereaceae
Fungus species
Fungi described in 1822
Fungi of North America
Taxa named by Lewis David de Schweinitz | Stereum fasciatum | [
"Biology"
] | 553 | [
"Fungi",
"Fungus species"
] |
75,955,442 | https://en.wikipedia.org/wiki/Holmium%20nitride | Holmium nitride is a binary inorganic compound of holmium and nitrogen with the chemical formula .
Synthesis
To produce holmium nitride nanoparticles, a plasma arc discharge technique can be employed.
In this process, holmium granules are placed in a copper crucible, which acts as the anode, while a tungsten cathode is used. Before starting, the furnace is evacuated , and this step is repeated twice to eliminate most of the air. Afterward, the furnace is filled with argon and nitrogen gas to a partial pressure of 4 kPa and a mixture ratio of 80% nitrogen to 20% argon.
Once the furnace is prepared, a current of ~220 A is applied along ~50 V, creating an arc plasma that generates holmium vapor. The holmium vapor then continues to react with the nitrogen gas in the surrounding environment, resulting in the formation of holmium nitride nanoparticles.
Physical properties
The compound forms crystals of cubic system.
References
Nitrides
Holmium compounds
Nitrogen compounds | Holmium nitride | [
"Chemistry"
] | 212 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,957,255 | https://en.wikipedia.org/wiki/Erbium%20nitride | Erbium nitride is a binary inorganic compound of erbium and nitrogen with the chemical formula .
Physical properties
The compound forms black powder. Chemically, ErN is more reactive and easily degraded in the air. High humidity causes ErN to hydrolyze, forming and ammonia.
ErN is known for its magnetic and optical properties.
Uses
The compound may be incorporated into III-nitride semiconductors in order to create new functional materials for optoelectronic and spintronic devices.
References
Nitrides
Erbium compounds
Nitrogen compounds | Erbium nitride | [
"Chemistry"
] | 116 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,957,413 | https://en.wikipedia.org/wiki/Villa%20rustica%20%28M%C3%B6ckenlohe%29 | The Villa rustica in Möckenlohe is the remains of a villa rustica from the 2nd or 3rd century near Möckenlohe, a part of the municipality of Adelschlag in the Landkreis Eichstätt in Bavaria.
Ancient remains were known here from the beginning of the 20th century. Aerial photos from 1983 show the plan of the villa, but also outbuildings. The main house was excavated from 1987 to 1989 and rebuilt in 1992/93.
The construction of the villa consisted of limestone masonry, which had an avant-corps on the front in the south, where the main entrance was. There was once also a colonnade here. The entire front was once around 30.5 meters long. A large courtyard opened behind the portico. Rooms were located to the west of the courtyard and to the south, where the portico also stood. One room had a basement, and at least two rooms had hypocaust underfloor heating. The villa was probably built under Emperor Hadrian and was abandoned after a fire in the middle of the third century. The modern replica does not correspond in every detail to the archaeological findings and is connected to a petting zoo.
See also
Villa rustica
References
Wolfgang Czysz, Karlheinz Dietz, Hans-Jörg Kellner, Thomas Fischer: Die Römer in Bayern. Stuttgart 1995, ,pp. 479–480.
Andreas A. Schaflitzl: "Der römische Gutshof von Möckenlohe, Lkr. Eichstätt". In: Bericht der Bayerischen Bodendenkmalpflege 53 (2012), pp. 85–229.
Galya Rosenstein: "Römische Gläser aus der Villa rustica von Möckenloh". In: Bericht der Bayerischen Bodendenkmalpflege, 53 (2012).
External links
Verein Römervilla Möckenlohe e.V.
Architectural history
Buildings and structures in Eichstätt (district)
Roman villas in Germany | Villa rustica (Möckenlohe) | [
"Engineering"
] | 424 | [
"Architectural history",
"Architecture"
] |
75,957,569 | https://en.wikipedia.org/wiki/Frequency%20%28marketing%29 | In marketing and advertising, frequency refers to the number of times a target audience is exposed to a particular message or advertisement within a given time frame. This concept is a fundamental element of marketing communication strategies, aiming to enhance brand recall, create awareness, and influence consumer behavior through repeated exposure.
From an audience perspective, Philip H. Dougherty says frequency can be interpreted as "how often consumers must see it before they can readily recall it and how many times it must be seen before attitudes are altered."
For a business, increased frequency is generally desirable. Some studies have shown that audiences respond more favorably from repeated exposures to advertisements (i.e., increased frequency). Moreover, to maximize return on ad spend (ROAS), some research suggests the repeat of exposures should be spread out (once-a-week) versus multiple times in a short-time period (multiple times in a day), in order not to overwhelm the target audience.
Construction
Television
In television media, frequency is calculated by dividing the number of impressions by the total audience population that was reached.
where
is the frequency
is the total number of impressions
is the total number of unique users (or reach)
Radio
In radio, frequency is calculated multiplying gross impressions, the total number of times a commercial is heard, divided by the total audience population that was reached.
where
is the gross impressions
is the Average Quarter-Hour persons, the "average number of persons listening to a particular station for at least five minutes during a 15-minute period"
is the total number of spots or commercials
is the total number of unique users (or reach)
Frequency capping
Frequency capping is a term in advertising that means restricting (capping) the number of times a specific visitor to a website is shown a particular advertisement (frequency). This restriction is applied to all websites that serve ads from the same advertising network.
Frequency capping is a feature within ad serving that allows to limit the maximum number of impressions/views a visitor can see a specific ad within a period of time. For example, "three views/visitor/24-hours" ("three views per visitor per 24-hours") means after viewing this ad three times, any visitor will not see it again for 24 hours. This feature uses cookies to remember the impression count. Non-cookies privacy-preserving implementation is also available.
Frequency capping is often cited as a way to avoid banner burnout, the point where visitors are being overexposed and response drops. This may be true for direct-response campaigns whose effectiveness is measured in click-throughs, but it might run counter to campaigns whose goal is brand awareness, as measured by non-click activity.
Effective frequency
The effective frequency is the number of times a person must be exposed to an advertising message before a response is made and before exposure is considered wasteful.
The subject of effective frequency is quite controversial. Many people have their own definition on what this phrase means. There are also numerous studies with their own theories or models as to what the correct number is for effective frequency.
There are several definitions of effective frequency:
Advertising Glossary defines effective frequency as "Exposures to an advertising message required to achieve effective communication. Generally expressed as a range below which the exposure is inadequate and above which the exposure is considered wastage."
Business Dictionary defines it as "Advertising, the theory that a consumer has to be exposed to an ad at least three times within a purchasing cycle (time between two consecutive purchases) to buy that product."
Marketing Power defines it as "An advertiser's determination of the optimum number of exposure opportunities required to effectively convey the advertising message to the desired audience or target market."
John Philip Jones says, "Effective frequency can mean that a single advertising exposure is able to influence the purchase of a brand. However, as all experienced advertising people know, the phrase was really coined to communicate the idea that there must be enough concentration of media weight to cross a threshold. Repetition was considered necessary, and there had to be enough of it within the period before a consumer buys a product to influence his or her choice of brand."
Theorists
Hermann Ebbinghaus
In 1879–80, Hermann Ebbinghaus conducted research on higher mental processes; he replicated the entire procedure in 1883–4. Ebbinghaus' methods achieved a remarkable set of results.
He was the first to describe the shape of the learning curve. He reported that the time required to memorize an average nonsense syllable increases sharply as the number of syllables increases.
He discovered that distributing learning trials over time is more effective in memorizing nonsense syllables than massing practice into a single session; and he noted that continuing to practice material after the learning criterion has been reached enhances retention.
Using one of his methods called savings as an index, he showed that the most commonly accepted law of association, viz., association by contiguity (the idea that items next to one another are associated) had to be modified to include remote associations (associations between items that are not next to one another in a list).
He was the first to describe primacy and recency effects (the fact that early and late items in a list are more likely to be recalled than middle items), and to report that even a small amount of initial practice, far below that required for retention, can lead to savings at relearning.
He even addressed the question of memorization of meaningful material and estimated that learning such material takes only about one tenth of the effort required to learn comparable nonsense material.
This learning curve research has been used to help researches study advertising message retention.
Thomas Smith
Thomas Smith wrote a guide called Successful Advertising in 1885. The saying he used is still being used today.
The first time people look at any given ad, they don't even see it.
The second time, they don't notice it.
The third time, they are aware that it is there.
The fourth time, they have a fleeting sense that they've seen it somewhere before.
The fifth time, they actually read the ad.
The sixth time they thumb their nose at it.
The seventh time, they start to get a little irritated with it.
The eighth time, they start to think, "Here's that confounded ad again."
The ninth time, they start to wonder if they're missing out on something.
The tenth time, they ask their friends and neighbors if they've tried it.
The eleventh time, they wonder how the company is paying for all these ads.
The twelfth time, they start to think that it must be a good product.
The thirteenth time, they start to feel the product has value.
The fourteenth time, they start to remember wanting a product exactly like this for a long time.
The fifteenth time, they start to yearn for it because they can't afford to buy it.
The sixteenth time, they accept the fact that they will buy it sometime in the future.
The seventeenth time, they make a note to buy the product.
The eighteenth time, they curse their poverty for not allowing them to buy this terrific product.
The nineteenth time, they count their money very carefully.
The twentieth time prospects see the ad, they buy what is offering.
Herbert E. Krugman
Herbert E. Krugman wrote "Why Three Exposures may be enough" while he was employed at General Electric. His theory has been adopted and widely in use in the advertising arena. The following statement encapsulates his theory: "Let me try to explain the special qualities of one, two and three exposures. I stop at three because as you shall see there is no such thing as a fourth exposure psychologically; rather fours, fives, etc., are repeats of the third exposure effect.
According to Krugman, there are only three levels of exposure in psychological, not media, terms: curiosity, recognition and decision.
See also
Digital marketing
Reach (advertising)
Marketing mix modeling
Gross rating point
Target rating point
References
Marketing
Marketing & Advertising articles by quality
Internet terminology
Online advertising
Audience measurement
Advertising
Promotion and marketing communications
Marketing analytics | Frequency (marketing) | [
"Technology"
] | 1,646 | [
"Computing terminology",
"Internet terminology"
] |
75,957,939 | https://en.wikipedia.org/wiki/Entoloma%20formosum | Entoloma formosum is an inconspicuous yellowish-brown mushroom in the family Entolomataceae which are distinguished by their pink angular (or similar) spores.
Description
Many Entoloma species are known to be quite difficult to identify, often requiring microscopic analysis or even DNA sequencing. E. formosum has a depressed brownish cap ranging in width with sometimes fine fibrillose hairs radially arranged. The stem is up to in height, and is buff with a darker gradient starting from the bottom. The gills are whitish when young, and become pinkish as the spores begin to color them. There is an almost exact look alike, named E. xanthocroum. It can be distinguished from E. formosum by its discolored gill edges and slightly larger spores.
See also
List of Entomola species
References
Entolomataceae
Fungus species
Taxa named by Elias Magnus Fries
Fungi described in 1821
Fungi of Europe
Fungi of North America | Entoloma formosum | [
"Biology"
] | 201 | [
"Fungi",
"Fungus species"
] |
75,959,750 | https://en.wikipedia.org/wiki/Nuclear%20Orthodoxy | Nuclear Orthodoxy (), also sometimes referred to as Atomic Orthodoxy, is a Russian eschatological political concept which believes that Russia must build up its military, particularly its nuclear arsenal, in order to prepare for the Second Coming. First conceived following the dissolution of the Soviet Union, Nuclear Orthodoxy has become a part of the ideology of the Russian Orthodox Church through its policy of "hagiopolitics".
History
Nuclear Orthodoxy was first formulated in the aftermath of the dissolution of the Soviet Union among Eurasianist political circles. The term was first coined by , who published a painting of a nuclear submarine with Christian imagery at the NovoNovosibirsk exhibition in Paris in 1999. The concept gradually became part of the Russian world ideology. In 2005, Fyodor Ushakov was recognised as patron saint of Russia's nuclear arsenal.
President Vladimir Putin first invoked Nuclear Orthodoxy in a 1 February 2007 press conference, where he stated that the Russian Orthodox Church and Russia's nuclear arsenal were "the components that strengthen Russian statehood and create the conditions for ensuring the country's internal and external security." Putin has continued to invoke Nuclear Orthodoxy on various occasions, such as a 2018 claim that Russians would "go to heaven as martyrs" and foreigners would "simply drop dead."
Nuclear Orthodoxy was further elaborated upon by Eurasianist ideologue Yegor Kholmogorov in 2009, where he argued that Russia must secure dominance over the West through military methods and nuclear blackmail. The same year, Patriarch Kirill of Moscow visited the city of Sarov, home to the All-Russian Scientific Research Institute of Experimental Physics and birthplace of Saint Seraphim of Sarov, where he said that Russia's nuclear weapons programme was the will of God.
Since the 2022 Russian invasion of Ukraine Nuclear Orthodoxy has gained increased attention, particularly as a result of heightened nuclear threats.
Beliefs
Kholmogorov outlined the principles of Nuclear Orthodoxy in a June 2007 lecture at the All-Russian Scientific Research Institute of Experimental Physics, where he stressed the Christian and eschatological nature of the ideology. As stated in the lecture, Nuclear Orthodoxy is focused on ensuring that the Holy Spirit is received by Russians, that demons are exorcised from Russia, and that Russia is prepared to maintain the Holy Rus' in preparation of the Second Coming, and that nuclear weapons will defend Russia from the forces of Satan.
According to Kholmogorov, three "straitjackets" were imposed upon humanity by God as a reaction to Satan's power. These "straitjackets" are mortality (in accordance with the fall of man), the disobedience of nature to man (in accordance with the Flood myth), and humanity's fragmentation along ethnic lines (in accordance with the Tower of Babel). Kholmogorov argued that there are three methods to overcoming these limitations: through the path of grace and humility, through the path of law and progress, and through the path of rebellion through occultism. Humility is considered by Kholmogorov to be positive and occultism negative, while progress is considered as neutral so long as it does not cross over with occultism.
Kholmogorov additionally argues that Russia's uniquely Christian nature was established by Sergius of Radonezh, and Russia later turned to autocracy under Ivan the Terrible in reaction to conflict with the Western world. He argues that the city of Sarov played a critical role in preventing Russia from becoming part of the west, both as the origin of Saint Seraphim and due to its role in producing nuclear weapons.
Kholmogorov has lastly categorised Nuclear Orthodoxy as a form of "hagiopolitics", a term also used by the Russian Orthodox Church to justify its support for nuclear proliferation. According to the ROC, nuclear weapons are a necessity to ensure the safety of Moscow, third Rome against the forces of evil. Nuclear Orthodoxy has been linked to similar ideas of by researchers, such as Maria Engström of Uppsala University, and been compared to jihadism for its emphasis on holy war.
References
Eschatology
Eurasianism
Nuclear warfare
Nuclear weapons of Russia
Orthodox fundamentalism
Russian nationalism
Russian Orthodox Church in Russia
Vladimir Putin | Nuclear Orthodoxy | [
"Chemistry"
] | 853 | [
"Radioactivity",
"Nuclear warfare"
] |
75,962,366 | https://en.wikipedia.org/wiki/Silicon%20Quantum%20Electronics%20Workshop | The Silicon Quantum Electronics Workshop (SiQEW) is a series of workshops on silicon quantum computing that date back to 2007.
References
Workshops
Quantum electronics | Silicon Quantum Electronics Workshop | [
"Physics",
"Materials_science"
] | 31 | [
"Nanotechnology",
"Quantum mechanics",
"Condensed matter physics",
"Quantum electronics"
] |
75,962,483 | https://en.wikipedia.org/wiki/C14H19FN2 | {{DISPLAYTITLE:C14H19FN2}}
The molecular formula C14H19FN2 may refer to:
5-Fluoro-DET
6-Fluoro-DET | C14H19FN2 | [
"Chemistry"
] | 43 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
75,962,511 | https://en.wikipedia.org/wiki/C18H19N3O3 | {{DISPLAYTITLE:C18H19N3O3}}
The molecular formula C18H19N3O3 may refer to:
Ainuovirine
RH-34 | C18H19N3O3 | [
"Chemistry"
] | 41 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
75,963,321 | https://en.wikipedia.org/wiki/Lemberg%20Medal | The Lemberg Medal, named after Max Rudolf Lemberg, the first president of the Australian Society for Biochemistry and Molecular Biology (ASBMB), is awarded annually to a scientist who has been a member for five or more years and who has "demonstrated excellence in Biochemistry and Molecular Biology and who has made significant contributions to the scientific community". The winner presents the Lemberg Lecture at the following ASBMB annual conference.
Recipients
Source: Lemberg Medallists, Australian Society for Biochemistry and Molecular Biology
References
Awards established in 1968
Biochemistry awards
Australian awards | Lemberg Medal | [
"Chemistry",
"Biology"
] | 111 | [
"Biochemistry",
"Biochemistry awards"
] |
75,964,056 | https://en.wikipedia.org/wiki/Punctularia%20atropurpurascens | Punctularia atropurpurascens, also known as violet crust or purple fuzz, is a species of fungus. Purple fuzz is a saprotrophic crust fungus. The preferred nutrient source of purple fuzz is the wood of deciduous trees. Purple fuzz is prone to guttation and weeps red. Purple fuzz appears to be a fairly widespread fungus capable of adapting to a variety of climates.
See also
Corticioid fungi
References
Fungi described in 1916
Punctulariaceae
Fungus species | Punctularia atropurpurascens | [
"Biology"
] | 106 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
75,964,907 | https://en.wikipedia.org/wiki/Marasmius%20plicatulus | Marasmius plicatulus, also known as the red pinwheel or pleated marasmius, is a species of fungus. According to the Fungi of California website, "This handsome Marasmius is recognized by its velvety mahogany cap, slender stature, widely spaced pallid to pinkish gills, and shiny, thin, wiry stipe." The red pinwheel is often found in association with oak trees or conifers, and flushes most commonly during the winter months of November to January. Of the Marasmius species found on the Pacific coast of North America, the pleated is physically the largest. The red pinwheel appears to be predominantly known from western/coastal North America, although it has been observed as far inland as Idaho.
References
Fungi described in 1897
Fungi of North America
plicatulus
Fungus species
Taxa named by Charles Horton Peck
Mycorrhizal associates of oaks | Marasmius plicatulus | [
"Biology"
] | 186 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
75,965,120 | https://en.wikipedia.org/wiki/Ytterbium%28III%29%20nitride | Ytterbium(III) nitride is a binary inorganic compound of ytterbium and nitrogen with the chemical formula .
Synthesis
Ytterbium(III) nitride can be prepared from the reaction of ytterbium hydride and ammonia at 800°C:
It can also be prepared from the reaction of ytterbium and nitrogen with an admixture of hydrogen under pressure at 500–600°C::
Physical properties
Ytterbium(III) nitride forms a black powder. The compound is notable for its high melting point.
Uses
Ytterbium(III) nitride holds potential applications in the fields of electronics and optics. It is also used as an additive for special alloys, ceramic materials, semiconductors.
References
Nitrides
Ytterbium(III) compounds
Nitrogen compounds | Ytterbium(III) nitride | [
"Chemistry"
] | 174 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,965,577 | https://en.wikipedia.org/wiki/Obelisk%20%28biology%29 | <noinclude>
An obelisk is a microscopic genetic element that consists of a type of infectious agent composed of RNA. Described as a "viroid-like element", they consist of RNA in a circular rod shape without any protein shell coating.
Obelisks were identified in 2024 through computational analysis of vast genetic datasets. Their RNA sequences are entirely novel, and their placement within the tree of life remains uncertain as they do not appear to have a shared ancestry with any other life form, virus, or viroid. Obelisks are currently classified as an enigmatic taxon, forming a distinct phylogenetic group.
Discovery
Obelisks were first described in a January 2024 preprint, by Stanford University scientists which sifted through genetic data. Currently, only a few methods are available for the identification of these elements from NGS data. The authors of the paper say that "Obelisks form their own distinct phylogenetic group", as their RNA sequences, discovered by computer-aided metatranscriptomics, are not homologous with the genomic sequence of any other life form. With their relationship to other organisms being unknown, they are an example of the incertae sedis, or "enigmatic taxa".
The authors of the January preprint named these sequences "obelisks" due to a predicted rod-like secondary structure: "At 1164 nt in length, the rod-like secondary structure was striking [...]"
Viroids were known to exist in plants and cause pathology, and there had been no evidence that they were in animals or bacteria. This marks the first time a viroid or viroid-like object has been found in bacteria or animals.
Distribution and pathology
Obelisks have been found in human stool samples, and inside specimens of Streptococcus sanguinis, a species of bacteria, taken from human mouths. Some human subjects hosted obelisks for more than 300 days. The initial study showed the presence of obelisks in about 7 percent of the stool samples, and about 50 percent of saliva samples, surveying individuals globally.
The effect of obelisks on human health, if any, is yet to be determined, as are issues such as their life cycles, and what factors their replication depend on.
Genetics and biochemistry
Features of obelisks include circular RNA genome assemblies with around 1000 base pairs, and rod-like secondary structures that encompass the entire genome. In contrast to viroids, their RNA is translated into proteins, tentatively called "oblins" in the preprint. The two proteins listed there have been named Oblin-1 and Oblin-2.
First structural predictions say that Oblin-1 can bind metal ions and thus could be involved in cellular signalling. Oblin-2 features a binding site which is typical of protein complexes, and might therefore bind to enzymes of its host cell.
References
RNA
Incertae sedis
Subviral agents | Obelisk (biology) | [
"Biology"
] | 601 | [
"Incertae sedis",
"Taxonomy (biology)"
] |
75,966,255 | https://en.wikipedia.org/wiki/Category%20of%20measurable%20spaces | In mathematics, the category of measurable spaces, often denoted Meas, is the category whose objects are measurable spaces and whose morphisms are measurable maps.
This is a category because the composition of two measurable maps is again measurable, and the identity function is measurable.
N.B. Some authors reserve the name Meas for categories whose objects are measure spaces, and denote the category of measurable spaces as Mble, or other notations. Some authors also restrict the category only to particular well-behaved measurable spaces, such as standard Borel spaces.
As a concrete category
Like many categories, the category Meas is a concrete category, meaning its objects are sets with additional structure (i.e. sigma-algebras) and its morphisms are functions preserving this structure. There is a natural forgetful functor
U : Meas → Set
to the category of sets which assigns to each measurable space the underlying set and to each measurable map the underlying function.
The forgetful functor U has both a left adjoint
D : Set → Meas
which equips a given set with the discrete sigma-algebra, and a right adjoint
I : Set → Meas
which equips a given set with the indiscrete or trivial sigma-algebra. Both of these functors are, in fact, right inverses to U (meaning that UD and UI are equal to the identity functor on Set). Moreover, since any function between discrete or between indiscrete spaces is measurable, both of these functors give full embeddings of Set into Meas.
Limits and colimits
The category Meas is both complete and cocomplete, which means that all small limits and colimits exist in Meas. In fact, the forgetful functor U : Meas → Set uniquely lifts both limits and colimits and preserves them as well. Therefore, (co)limits in Meas are given by placing particular sigma-algebras on the corresponding (co)limits in Set.
Examples of limits and colimits in Meas include:
The empty set (considered as a measurable space) is the initial object of Meas; any singleton measurable space is a terminal object. There are thus no zero objects in Meas.
The product in Meas is given by the product sigma-algebra on the Cartesian product. The coproduct is given by the disjoint union of measurable spaces.
The equalizer of a pair of morphisms is given by placing the induced sigma-algebra on the subset given by the set-theoretic equalizer. Dually, the coequalizer is given by placing the quotient sigma-algebra on the set-theoretic coequalizer.
Direct limits and inverse limits are the set-theoretic limits with the final and initial sigma-algebra respectively. Canonical examples of direct and inverse systems are the ones arising from filtrations in probability theory, and the limits and colimits of such systems are, respectively, the join and the intersection of sigma-algebras.
Other properties
The monomorphisms in Meas are the injective measurable maps, the epimorphisms are the surjective measurable maps, and the isomorphisms are the isomorphisms of measurable spaces.
The split monomorphisms are (essentially) the inclusions of measurable retracts into their ambient space.
The split epimorphisms are (up to isomorphism) the measurable surjective maps of a measurable space onto one of its retracts.
Meas is not cartesian closed (and therefore also not a topos) since it does not have exponential objects for all spaces.
See also
Citations
References
Categories in category theory
Measure theory
Probability theory | Category of measurable spaces | [
"Mathematics"
] | 786 | [
"Mathematical structures",
"Category theory",
"Categories in category theory"
] |
75,966,601 | https://en.wikipedia.org/wiki/Lawvere%27s%20fixed-point%20theorem | In mathematics, Lawvere's fixed-point theorem is an important result in category theory. It is a broad abstract generalization of many diagonal arguments in mathematics and logic, such as Cantor's diagonal argument, Cantor's theorem, Russell's paradox, Gödel's first incompleteness theorem, Turing's solution to the Entscheidungsproblem, and Tarski's undefinability theorem.
It was first proven by William Lawvere in 1969.
Statement
Lawvere's theorem states that, for any Cartesian closed category and given an object in it, if there is a weakly point-surjective morphism from some object to the exponential object , then every endomorphism has a fixed point. That is, there exists a morphism (where is a terminal object in ) such that .
Applications
The theorem's contrapositive is particularly useful in proving many results. It states that if there is an object in the category such that there is an endomorphism which has no fixed points, then there is no object with a weakly point-surjective map . Some important corollaries of this are:
Cantor's theorem
Cantor's diagonal argument
Diagonal lemma
Russell's paradox
Gödel's first incompleteness theorem
Tarski's undefinability theorem
Turing's proof
Löb's paradox
Roger's fixed-point theorem
Rice's theorem
References
Category theory
Mathematical theorems | Lawvere's fixed-point theorem | [
"Mathematics"
] | 302 | [
"Functions and mappings",
"Mathematical structures",
"Mathematical objects",
"Fields of abstract algebra",
"Mathematical relations",
"Category theory",
"nan",
"Mathematical problems",
"Mathematical theorems"
] |
75,967,770 | https://en.wikipedia.org/wiki/Amir%20Caspi | Amir Caspi is a solar physicist based at the Southwest Research Institute in Boulder, Colorado. He is particularly known for his work on X-ray spectroscopy of the Sun and the solar corona, and for advancing the art of eclipse observations of the corona to improve scientific understanding.
Caspi is the PI of the CubeSat Imaging X-ray Solar Spectrometer (CubIXSS), a mission currently in development for NASA's Heliophysics Division. He has held major roles on several other CubeSats, including the predecessor Miniature X-ray Solar Spectrometer CubeSat (MinXSS).
Caspi's work on solar flares and solar X-ray emission includes important observations and statistical analyses of line and continuum emissions from ultra-hot solar flares,
and extensive work on instrumentation and analysis techniques needed to advance understanding of coronal heating and solar flare dynamics. He is the Student Mentor for the Student Thermal and Energetic Activity Monitor (STEAM) instrument on the PUNCH mission scheduled to launch in 2025.
Caspi leads the Citizen CATE 2024 experiment to deploy distributed observing stations along the track of the April 8, 2024 North American solar eclipse, to observe the polarized solar corona in high resolution for a full hour. He is also noted for adapting NASA's WB-57 aircraft to obtain high altitude eclipse observations, both extending the length of eclipse observations and reducing the effects of Earth's atmosphere on the final data.
References
Living people
Year of birth missing (living people)
Astrophysicists | Amir Caspi | [
"Physics"
] | 308 | [
"Astrophysicists",
"Astrophysics"
] |
75,968,411 | https://en.wikipedia.org/wiki/Citation%20cartel | A citation cartel is a group of academic authors who collude to egregiously cite one another's publications in order to increase their citation counts. In many cases the cited works have no strong relevance to the works they are cited in.
Alleged citation cartels have been found in numerous academic fields, including mathematics, medicine and dentistry. Possible citation cartels can be detected by network analysis of the citation graph.
See also
Clique
Coercive citation
References
Academic publishing
Social groups
Citation metrics
Scientific misconduct | Citation cartel | [
"Technology"
] | 104 | [
"Scientific misconduct",
"Ethics of science and technology"
] |
75,968,430 | https://en.wikipedia.org/wiki/Lanthanum%28III%29%20iodate | Lanthanum(III) iodate is an inorganic compound with the chemical formula La(IO3)3.
Preparation
Lanthanum(III) iodate can be obtained by reacting a La3+ salt with potassium iodate or ammonium iodate and precipitating it:
La3+ + 3 IO3− → La(IO3)3↓
Properties
Lanthanum(III) iodate can disproportionate and decompose to a periodate when heated:
10 La(IO3)3 → 2 La5(IO6)3 + 12 I2↑ + 27 O2↑
References
Iodates
Lanthanum compounds | Lanthanum(III) iodate | [
"Chemistry"
] | 136 | [
"Iodates",
"Oxidizing agents"
] |
75,969,668 | https://en.wikipedia.org/wiki/Category%20of%20Markov%20kernels | In mathematics, the category of Markov kernels, often denoted Stoch, is the category whose objects are measurable spaces and whose morphisms are Markov kernels.
It is analogous to the category of sets and functions, but where the arrows can be interpreted as being stochastic.
Several variants of this category are used in the literature. For example, one can use subprobability kernels instead of probability kernels, or more general s-finite kernels.
Also, one can take as morphisms equivalence classes of Markov kernels under almost sure equality; see below.
Definition
Recall that a Markov kernel between measurable spaces and is an assignment which is measurable as a function on and which is a probability measure on . We denote its values by for and , which suggests an interpretation as conditional probability.
The category Stoch has:
As objects, measurable spaces;
As morphisms, Markov kernels between them;
For each measurable space , the identity morphism is given by the kernel
for all and ;
Given kernels and , the composite morphism is given by
for all and .
This composition formula is sometimes called the Chapman-Kolmogorov equation.
This composition is unital, and associative by the monotone convergence theorem, so that one indeed has a category.
Basic properties
Probability measures
The terminal object of Stoch is the one-point space . Morphisms in the form can be equivalently seen as probability measures on , since they correspond to functions , i.e. elements of .
Given kernels and , the composite kernel gives the probability measure on with values
for every measurable subset of .
Given probability spaces and , a measure-preserving Markov kernel is a Markov kernel such that for every measurable subset ,
Probability spaces and measure-preserving Markov kernels form a category, which can be seen as the slice category .
Measurable functions
Every measurable function defines canonically a Markov kernel as follows,
for every and every . This construction preserves identities and compositions, and is therefore a functor from Meas to Stoch.
Isomorphisms
By functoriality, every isomorphism of measurable spaces (in the category Meas) induces an isomorphism in Stoch. However, in Stoch there are more isomorphisms, and in particular, measurable spaces can be isomorphic in Stoch even when the underlying sets are not in bijection.
Relationship with other categories
Stoch is the Kleisli category of the Giry monad. This in particular implies that there is an adjunction
between Stoch and the category of measurable spaces.
The left adjoint of the adjunction above is the identity on objects, and on morphisms it gives the canonical Markov kernel induced by a measurable function described above.
As mentioned above, one can construct a category of probability spaces and measure-preserving Markov kernels as the slice category .
Similarly, the category of probability spaces can be seen as the comma category .
Particular limits and colimits
Since the functor is left adjoint, it preserves colimits. Because of this, all colimits in the category of measurable spaces are also colimits in Stoch. For example,
The initial object is the empty set, with its trivial measurable structure;
The coproduct is given by the disjoint union of measurable spaces, with its canonical sigma-algebra.
The sequential colimit of a decreasing filtration is given by the intersection of sigma-algebras.
In general, the functor does not preserve limits. This in particular implies that the product of measurable spaces is not a product in Stoch in general. Since the Giry monad is monoidal, however, the product of measurable spaces still makes Stoch a monoidal category.
A limit of particular significance for probability theory is de Finetti's theorem, which can be interpreted as the fact that the space of probability measures (Giry monad) is the limit in Stoch of the diagram formed by finite permutations of sequences.
Almost sure version
Sometimes it is useful to consider Markov kernels only up to almost sure equality, for example when talking about disintegrations or about regular conditional probability.
Given probability spaces and , we say that two measure-preserving kernels are almost surely equal if and only if for every measurable subset ,
for -almost all .
This defines an equivalence relation on the set of measure-preserving Markov kernels .
Probability spaces and equivalence classes of Markov kernels under the relation defined above form a category. When restricted to standard Borel probability spaces, the category is often denoted by Krn.
See also
Measurable space
Markov kernel
Categorical probability
Citations
References
Further reading
https://ncatlab.org/nlab/show/Stoch
https://ncatlab.org/nlab/show/Krn
Categories in category theory
Measure theory
Probability theory | Category of Markov kernels | [
"Mathematics"
] | 1,024 | [
"Mathematical structures",
"Category theory",
"Categories in category theory"
] |
75,969,672 | https://en.wikipedia.org/wiki/Salsolinol | Salsolinol is a chemical compound derived from dopamine which plays a role in neurotransmission and is neurotoxic.
It has been linked to dopamine-related disorders including Parkinson's disease and alcohol use disorder. It is both synthesized in the human body and ingested in several common dietary sources.
Chemistry and structure
Salsolinol is a catechol isoquinoline which is a yellow solid at room temperature. Salsolinol, as a chiral molecule, comes in two enantiomers: (R)-salsolinol and (S)-salsolinol. The two may have different biological effects.
The racemate can be synthesized via a Pictet-Spengler reaction. A chemoenzymatic, enantioselective synthesis of the (R)-enantiomer has also been reported. Salsolinol has been used as a starting material to prepare some tetrahydroisoquinoline-based prospective drugs.
Biochemistry
Natural occurrence
Salsolinol is found in several edible plants, most prominently bananas and cocoa products as well as beer. Other plants, including black cohosh, which is used in many herbal remedies, also contain salsolinol.
Biosynthesis
Salsolinol is endogenously synthesized by multiple routes, although its origin in the human body remains controversial. There are two main routes for its production: one which is through a non-enantiospecific Pictet-Spengler reaction of dopamine and acetaldehyde, and one which is mediated by the enzyme salsolinol synthase.
Salsolinol synthase exclusively produces the (R)-enantiomer of salsolinol.
It has been speculated that salsolinol may also arise from salsolinol-1-carboxylic acid, which is formed by the reaction of dopamine and pyruvic acid. This transformation would occur via a proposed enzymatic pathway that has not been elucidated yet.
Metabolism
Salsolinol is metabolized by an N-methyltransferase enzyme into N-methyl-(R)-salsolinol. This can then be converted by an amine oxidase into 1,2-dimethyl-6,7-dihydroxyisoquinolinium (DMDHIQ+). It can also be methylated to form its 7-methoxy and 6-methoxy versions by the enzyme catechol-O-methyltransferase (COMT).
Role in the body
Neurotoxicity and neurotransmission
Salsolinol binds to several receptors associated with dopaminergic pathways. It may be an agonist of the μ-opioid receptor and of dopaminergic D1 and D3 receptors.
Salsolinol itself also appears to be neurotoxic, the mechanism of which is not clear. Its metabolites, including N-methyl-(R)-salsolinol, also exhibit neurotoxic effects.
Prolactin
Salsolinol has been shown to be involved in the secretion of prolactin in the pituitary gland in lactating rats and lactating sheep. Administration of a solution of salsolinol was not shown to raise prolactin levels in human women.
Disease and disorders
Parkinson's disease
Salsolinol is detectable in the cerebrospinal fluid of Parkinson's disease (PD) patients and is involved in the pathogenesis of PD. It is known to exercise inhibitory effects on tyrosine hydroxylase and to be toxic to dopaminergic neurons.
A mechanism for the induction of Parkinson's by salsolinol is linked to its mediation of pyroptosis.
Alcohol intake and alcohol use disorders
The connection between salsolinol and alcohol intake remains controversial. An early hypothesis was that the synthesis of salsolinol in the human body was caused by ethanol consumption, because it was being made from dopamine and acetaldehyde (a metabolite of ethanol). Several studies in the 1970s and 80s would seem to corroborate this link. However, no consistent connection between ethanol intake and salsolinol levels were conclusively established. As of the 2020s, it is understood that the primary contributor to levels of salsolinol in blood plasma is dietary intake, not acute ethanol consumption. Part of the challenge in studying this is that salsolinol also is produced endogenously, and in all cases its levels are very low, making it difficult to detect and quantify with precision.
Further confounding the issue, there is evidence that salsolinol may be implicated in alcohol use disorder and may play a role in increasing cravings for ethanol. (R)-Salsolinol stereospecifically induces behavioral sensitization and leads to excessive alcohol intake in rats.
See also
Norsalsolinol
6-Hydroxydopamine
MPTP
Rotenone
References
Catechols
Dopamine
Human pathological metabolites
Monoaminergic neurotoxins
Tetrahydroisoquinolines | Salsolinol | [
"Chemistry"
] | 1,098 | [
"Alkaloids by chemical classification",
"Tetrahydroisoquinoline alkaloids"
] |
75,972,033 | https://en.wikipedia.org/wiki/Land%20Transport%20%28Clean%20Vehicle%20Discount%20Scheme%20Repeal%29%20Amendment%20Act%202023 | The Land Transport (Clean Vehicle Discount Scheme Repeal) Amendment Act 2023 is a New Zealand Act of Parliament that amends various legislation to end the Clean Car Discount by 31 December 2023. The Clean Car Discount programme had been introduced by the previous Sixth Labour Government to encourage New Zealand consumers to buy electrical and hybrid vehicles through a tax on high-emissions vehicles such as utes. The Clean Vehicle Discount Scheme Repeal Amendment Act was introduced and passed into law under urgency on 12 December 2023 by the National-led coalition government. It received royal assent on 19 December 2023.
Key provisions
The Bill amends the Land Transport Act 1998, Land Transport Management Act 2003, and several associated regulations including the Land Transport (Motor Vehicle Registration and Licensing) Regulations 2011, Energy Efficiency (Vehicle Energy Economy Labelling) Regulations 2007 and Land Transport (Clean Vehicle Discount Scheme Charges) Regulations 2022 to remove references to the Clean Car Discount programme from New Zealand law.
Background
In mid–June 2021, the Sixth Labour Government announced that it would introduce subsidies to make electric vehicles cheaper while raising the price of new petrol and new diesel vehicles, commencing in July 2021. This policy announcement followed a report by the Climate Change Commission on 9 June 2021 advocating the reduction of farm animal numbers, a ban on new household gas connections by 2025, and a shift to electric vehicles in order to reduce greenhouse emissions. In response to the policy announcement, EV City owner David Boot said that it would boost demand for electric cars while expressing concern about the need for educating electric car users. Motor Trade Association chief executive Craig Pomare claimed that the rebate would not be enough to encourage motor users to make the switch to electric cars while Federated Farmers national president Andrew Hoggard expressed concerns about the lack of electric vehicle alternatives for farmers and tradespersons.
In July 2021, the farming advocacy group Groundswell NZ called for the abolition of the Clean Car rebate scheme, regarding it as a "ute tax". They said there were no electrical alternatives to the utes widely used by farmers, horticulturalists, industry support people, and tradespersons.
The Clean Car Discount was envisioned as financially neutral with the "Ute Tax" charges covering the rebates and administration costs. However, by 2023, the scheme had received more money in rebates than in charges from the "ute tax." By December 2023, the Government had paid out NZ$579 million in rebates and NZ$13.5 million in administrative costs, while the Ute tax charges had only generated NZ$290 million, leaving taxpayers with a deficit of NZ$302.5 million.
During the 2023 New Zealand general election, the opposition National and ACT parties campaigned on repealed the Clean Car Discount, arguing that subsidising the purchase of electric and hybrid vehicles through a "ute tax" of up to NZ$6,900 on utility vehicles was unfair on groups like farmers, who had no viable low-emission alternative to utes. Following the 2023 election, negotiations between the National, ACT and New Zealand First parties led to the formation of a National-led coalition government in late November 2023. On 29 November, the Government released its 100-day plan which included repealing the previous Labour Government's Clean Car discount programme. Scrapping the "Ute tax" and the Clean Car discount was one of the terms of National's coalition agreement with ACT.
Legislative passage
On 14 December 2023, the Government passed the Land Transport (Clean Vehicle Discount Scheme Repeal) Amendment Act 2023 under urgency, which meant that all three readings of the bill were held that day. While the governing National, ACT and NZ First parties supported the Bill, it was opposed by the opposition Labour, Green and Māori parties. As a result, the Clean Car Discount ended on 31 December 2023 after the Bill received royal assent. That same week, the National-led government passed legislation repealing the previous government's dual mandate for the Reserve Bank of New Zealand and Fair Pay Agreements Act 2022.
Notes and references
External links
2023 in New Zealand law
2023 in the environment
Transport law in New Zealand
Environmental mitigation
Sixth National Government of New Zealand | Land Transport (Clean Vehicle Discount Scheme Repeal) Amendment Act 2023 | [
"Chemistry",
"Engineering"
] | 851 | [
"Environmental mitigation",
"Environmental engineering"
] |
75,972,575 | https://en.wikipedia.org/wiki/Hygrocybe%20laetissima | Hygrocybe laetissima, also known as the cherry-red waxy cap, is a species of gilled mushroom found in North America. It appears to flourish in association with redwood forests. The authors of Mushrooms of the Redwood Coast note that this waxy cap is superficially similar to other waxy caps, including Hygrocybe splendidissima, Hygrocybe punicea, Hygrocybe aurantiosplendens, and Hygrocybe marchii. It also overlaps somewhat in range and appearance with Hygrocybe coccinea. This one has the coloration of a Rainier cherry. Not recommended as an edible mushroom because close cousins (namely, punicea) have made people sick. This mushroom species was first described by Alexander H. Smith and L. R. Hesler.
See also
List of Hygrocybe species
References
Fungi described in 1942
Fungi of North America
Fungus species
laetissima
Taxa named by Alexander H. Smith
Taxa named by Lexemuel Ray Hesler | Hygrocybe laetissima | [
"Biology"
] | 227 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
75,974,852 | https://en.wikipedia.org/wiki/Dysprosium%20nitride | Dypsrosium nitride is a binary inorganic compound of dysprosium and nitride with the chemical formula .
Preparation
Dysprosium can be prepared from the reaction of finely ground dysprosium, dysprosium hydride, or the dysprosium amalgam with nitrogen at 800–1000°C:
Physical properties
Dypsrosium nitride forms gray crystals of cubic system; cell parameter a = 0.490 nm, Z = 4. It is a good conductor of electricity and reacts with water. It is known for its magnetic properties and high melting point.
References
Nitrides
Dysprosium compounds
Nitrogen compounds | Dysprosium nitride | [
"Chemistry"
] | 145 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
75,974,890 | https://en.wikipedia.org/wiki/Md.%20Abul%20Kashem | Md. Abul Kashem is a Bangladeshi academic and the former vice-chancellor of the Bangladesh University of Textiles.
Early life
Kashem completed his undergraduate degree at the College of Textile Technology in 1978. He completed his master's degree at a university in the United Kingdom in 1988.
Career
Kashem joined the technical department of the College of Textile Technology as a lecturer.
Kashem was promoted to full professor in 2007 and was appointed acting principal of the College of Textile Technology (upgraded to Bangladesh University of Textiles in 2010).
From 2009 to 2014, Kashem was the chairman of the Bangladesh Technical Education Board. From 2011 to 2012, he was the additional director general of the Directorate of Technical Education.
Kashem was the head of the department of apparel engineering at the Bangladesh University of Textiles. In February 2019, he was appointed the vice-chancellor of Bangladesh University of Textiles by President Mohammad Abdul Hamid. Kashem requested students of the university who blocked roads in January 2022 demanding online exams during the COVID-19 pandemic in Bangladesh to end their protests. He is one of two vice chancellors of public universities in Bangladesh without a PhD, the other is Farid Uddin Ahmed.
In 2023, Shah Alimuzzaman Belal was appointed vice-chancellor of Bangladesh University of Textiles replacing Kashem.
References
Living people
Textile engineers
Bangladeshi engineers
Bangladesh University of Textiles alumni
Bangladeshi academic administrators
Year of birth missing (living people) | Md. Abul Kashem | [
"Engineering"
] | 297 | [
"Textile engineers",
"Textile engineering"
] |
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