id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
62,762,777 | https://en.wikipedia.org/wiki/CALLISTO | CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss-back Operations) is a reusable VTVL demonstrator propelled by a small 40 kN Japanese LOX-LH2 rocket engine. It is being developed jointly by the French (CNES), German (DLR) and Japanese (JAXA) national space agencies.
The goals for CALLISTO are to mature and demonstrate the technologies which are necessary to build and operate a reusable launch vehicle, but also to better assess the operational cost of such a vehicle. The first flight was originally planned to occur in late 2020; it has since been postponed to 2025 at the earliest. Following the programme's conclusion, the experiences and technologies gained through CALLISTO will be harnessed to benefit other ongoing and future space programmes, such as the development of the European reusable launcher Ariane Next.
Development
During the 2010s, various aerospace entities, both in the public and private sector, became increasingly interested in the aspect of reusability, in particular Vertical takeoff, vertical landing (VTVL) rocket elements, as a means of reducing the cost of space-based activities. Companies such as SpaceX had demonstrated their own progress in the field, leading to agencies in Russia, China, and Europe announcing their own reusable rocket projects. By the mid-2010s, development of the pan-European Ariane 6 launcher was well-underway, and incorporated a reusable engine. However, some officials in both France and Germany felt that greater emphasis on reusability was necessary, and that future rockets needed to go beyond what was then underway. According, these nations begun to collaborate on a tentative research effort that would crystalise as CALLISTO; a test rocket aimed at investigating, demonstrating, and maturing relevant technologies in the field of reusability.
A major focus area for CALLISTO is to evaluate the maintenance, repair, and overhaul of the vehicle between flights; it is hoped that it could perform at least eight launches within six months. It is also sought to perform at least one landing with a minimum non-gravitational acceleration of 1.3g, as well as to demonstrate a large and rapid manoeuvre at low dynamic pressure and a vertical landing which includes both a boostback manoeuver and an unpowered aerodynamic manoeuver. The economics involved in all such operations are also to be stringently evaluated.
Upon the project's launch in 2015, CALLISTO was not driven by the European Space Agency (ESA); instead, it was originally a joint project between the CNES and DLR alone. In June 2017, the JAXA opted to join the CALLISTO partnership; around this time, it was agreed that Japan will provide the engine for the rocket, that being the 40 kN re-ignitable LOx/LH2 engine developed by JAXA for its Reusable Sounding Rocket programme. It will be modified to generate 15 percent greater thrust and to provide a throttling range from 16 to 46 kN, permitting adequate control of the vehicle during the landing phase.
Various aspects of the project have been divided between the partner agencies: the CNES is responsible for the hydrogen peroxide thrusters, telemetry, neutralisation system, ground segment, and will also perform final assembly of the equipment bay; the DLR is responsible for the fairing, navigation, fins, equipment bay structure, hydrogen tank, and the landing system; and at last, the JAXA is responsible for the oxygen tank, aft bay structure, power supply, and propulsion. All three organisations will work on the onboard computer and flight software. Experience and technologies are being drawn from multiple existing programmes, including the Vega expendable launch system and the Space Rider lifting body spaceplane.
Following the project's preliminary design review in late 2019, the vehicle's configuration was frozen. Possessing a height of 13.5 m and a diameter of 1.1 m, CALLISTO is a relatively compact rocket, a feat aided by its role as a demonstrator rather that an end product in and of itself. It will have a dry mass of 1,520 kg and a take-off mass of 3,600 kg. The flight control system incorporates a total of four deployable fins, along with two electromechanical actuators to gimble the engine, and eight hydrogen peroxide thrusters amongst other elements. It is furnished with four deployable landing legs for use during the landing phase.
In comparison to the established Ariane programme, CALLISTO has been described as being a relatively austere effort, operating on a budget between 1 and 2 percent of that allocated to Ariane. In 2018, it was stated that the project's timetable had scheduled the first flight of the rocket to take place sometime in late 2020, as well as for flight testing to be completed by the end of 2021. The flight test programme was set to be entirely performed at the newly-built commercial launch facility at the Guiana Space Centre, although considerations were made towards the use of alternative landing sites on both land and sea (the latter using barges).
Launch delayed from 2020
By mid 2019, flight tests were expected to start in 2022.
In 2021, CALLISTO reportedly passed its System Design Key Point, confirming the definition of the preliminary system design review. Numerous flight-worthiness reviews are anticipated to take place in 2024 ahead of a decision to proceed with flight testing.
, the first test flight is expected to take place in the 2025–2026 timeframe.
See also
References
Reusable launch systems
Partially reusable space launch vehicles
Space launch vehicles of Europe
Space programs
European space programmes
Spaceflight technology | CALLISTO | [
"Astronomy",
"Engineering"
] | 1,152 | [
"Space programs",
"Rocketry stubs",
"European space programmes",
"Astronomy stubs"
] |
62,763,473 | https://en.wikipedia.org/wiki/Zanardinia | Zanardinia is a monotypic genus of seaweed in the brown algae (class Phaeophyceae). The only species, Zanardinia typus, commonly known as penny weed, is native to the northeastern Atlantic Ocean and the Mediterranean Sea.
The genus was circumscribed by Giovanni Domenico Nardo ex Giovanni Antonia Maria Zanardini in Mem. Real. Accad. Sci. Torino ser.2, vol.4 on page 236 in 1841.
The genus name of Zanardinia is in honour of Giovanni Antonio Maria Zanardini (1804–1878), who was an Italian physician and botanist who specialized in the field of phycology.
Description
This brown alga is loosely secured to the rock by the felted rhizoids on the underside. Young individuals are circular and have a smooth surface and a double fringe of short hairs round the margin. Older individuals may be up to across and be fan-shaped or have broad blades with irregular margins. The consistency of the thallus is cartilaginous or leathery, and the colour is yellowish-brown or olive brown. Portions that become detached and wash up on the shore may crinkle as they dry and resemble pieces of blackish leather. This species could be confused with Cutleria adspersa, but that species tends to grow in brightly-lit, very shallow places while Z. typus prefers deeper, shadier habitats. Also, the upper and lower surfaces of the thallus of C. adspersa appear similar, but Z. typus has a distinctively-felted under surface.
Distribution and habitat
Zanardinia typus is found in the northeastern Atlantic Ocean and the Mediterranean Sea, its range including southwestern Britain and Ireland, the Atlantic coast of France, Spain and Portugal, the western Mediterranean Sea, the Adriatic Sea and the Black Sea. It grows on rock and silty boulders in the shallow subtidal zone at depths down to about .
Biology
Growth in this species is "trichothallic", meaning that it occurs at the base of the marginal hairs. The edge of the thallus is two cells thick, and in the growth zone, the cells divide several times to form a thickened area with an upper cortex with about five rows of cells, a central parenchyma composed of long, thick-walled cells, and a lower cortex, with one or two rows of cells from which the rhizoids emerge. There is an alternation of generations in this brown alga into sporophytes and gametophytes, although these are similar in appearance. The reproductive organs differentiate on the upper surface of the thallus. The alga can also reproduce vegetatively, with cup-shaped new growths developing on old fronds.
References
Brown algae
Monotypic brown algae genera
Taxa named by Giovanni Domenico Nardo | Zanardinia | [
"Biology"
] | 581 | [
"Algae",
"Brown algae"
] |
62,763,880 | https://en.wikipedia.org/wiki/Norman%20Laurence%20Gilbreath | Norman Laurence Gilbreath (born 1936) is an American magician and author known for originating the Gilbreath shuffle. He is also known for Gilbreath's conjecture concerning prime numbers.
Life and career
Gilbreath got a BS in mathematics at University of California, Los Angeles (UCLA). Following graduate work in applied mathematics, which saw him work under C. C. Chang, he spent his entire career at the Rand Corporation as an expert on compilers and optimization tasks. His book Magic for an Audience was published in 1989 as a series of three articles in Genii Magazine. He lives in Los Angeles and performed regularly in the 2000s at Hollywood's Magic Castle.
The Gilbreath shuffle is a method of shuffling a deck of cards, by riffling two packs of cards after reversing one of them. Unlike a standard riffle, it preserves certain properties of the sequence of cards, leading to its use in magic tricks.
Gilbreath introduced the Gilbreath principle the basis of card tricks using the Gilbreath shuffle in 1958 in an article in Genii magazine. In 1966 he published a generalization that is now called the Second Gilbreath principle. But the principal only became well known after Martin Gardner wrote about it in his July 1972 "Mathematical Games column" in Scientific American.
In number theory, he is known for Gilbreath's conjecture, an unproven pattern in the difference sequences of prime numbers. Gilbreath found this as a student in 1958 at UCLA. Two other students, R. B. Killgrove and K. E. Ralston, took advantage of the state-of-the-art SWAC computer installed at UCLA and confirmed it for the first 63419 primes. Unknown to them, the same pattern had been observed many years earlier by François Proth, but it is by Gilbreath's name that the conjecture is now known.
Books
Magic for an Audience, Genii Magazine, Vol. 52, No. 09-10-11, Spring 1989.
Beyond Imagination, Publisher: H&R Magic Books (2014).
References
External links
Norman Gilbreath Live
American magicians
Recreational mathematicians
American applied mathematicians
1936 births
Living people | Norman Laurence Gilbreath | [
"Mathematics"
] | 449 | [
"Recreational mathematics",
"Recreational mathematicians"
] |
62,766,022 | https://en.wikipedia.org/wiki/2218%20aluminium%20alloy | 2218 aluminium alloy is an alloy in the wrought aluminium-copper family (2000 or 2xxx series). It is one of the most complex grades in the 2000 series, with at least 88.4% aluminium by weight. Unlike most other aluminium-copper alloys, 2218 is a high work-ability alloy, with relatively low for 2xxx series alloy yield strength of 255 MPa. Despite being highly alloyed, it have a good corrosion and oxidation resistance due sacrificial anode formed by magnesium inclusions, similar to marine-grade 5xxx series alloys. Although 2218 is wrought alloy, owing to granular structure it can be used in casting and been precisely machined after casting. It is easy to weld, coat, or glue.
Good workability, thermal conductivity and dimensional stability make 2218 alloy a material of choice whenever high-precision parts subject to thermal shocks (especially piston engine cylinders and cylinder heads) are needed.
2218 alloy can be heat treated to increase tensile strength in expense of workability, with most common grades been F, T61, T71 and T72.
Alternative names for 2218 alloy are A2218 and A92218.
Chemical Composition
The chemical composition of 2218 alloy is poorly standardized, with several variants in production. All variants include both copper (4%) and magnesium (1.5%) as major alloying elements. Common alloy variants also include 2% of nickel.
The alloy composition of 2218 aluminium is:
Aluminium: 91.35 to 92.95%
Copper: 3.5 to 4.5%
Magnesium: 1.2 to 1.8%
Nickel: 1.7 to 2.3%
Iron: 1% max
Silicon: 0.9% max
Zinc: 0.25% max
Manganese: 0.5% max
Tin: 0.25% max
Chromium: 0.1% max
See also
Y alloy (precursor of A2218 with same major alloying elements)
References
Aluminium alloy table
Aluminium alloys
Aluminium–copper alloys | 2218 aluminium alloy | [
"Chemistry"
] | 422 | [
"Alloys",
"Aluminium alloys"
] |
62,766,198 | https://en.wikipedia.org/wiki/Ina%20Kersten | Ina Kersten (born 1946) is a German mathematician and former president of the German Mathematical Society. Her research concerns abstract algebra including the theory of field extensions and algebraic groups. She is a professor emerita at the University of Göttingen.
Kersten was born in Hamburg, and earned her Ph.D. at the University of Hamburg in 1977. Her dissertation, p-Algebren über semilokalen Ringen, was supervised by Ernst Witt.
She completed a habilitation at the University of Regensburg in 1983.
Kersten was president of the German Mathematical Society from 1995 to 1997, which meant she was the first woman to head the society. Under her leadership, the society founded the journal Documenta Mathematica.
References
External links
Home page
1946 births
Living people
20th-century German mathematicians
German women mathematicians
Algebraists
University of Hamburg alumni
Academic staff of the University of Göttingen
Presidents of the German Mathematical Society | Ina Kersten | [
"Mathematics"
] | 188 | [
"Algebra",
"Algebraists"
] |
62,766,227 | https://en.wikipedia.org/wiki/TOI-700 | TOI-700 is a red dwarf 101.4 light-years away from Earth located in the Dorado constellation that hosts TOI-700 d, the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS).
Nomenclature and history
The acronym "TOI" refers to stars and exoplanets studied by TESS, and is short for: "Transiting Exoplanet Survey Satellite Object of Interest".
Stellar characteristics
TOI-700 is a red dwarf of spectral class M (much redder, cooler, and dimmer than the sun) that is 40% the mass, 40% the radius and 55% of the temperature of the Sun. The star is bright with low levels of stellar activity. Over the 11 sectors observed with TESS, the star does not show a single white-light flare. The low rotation rate is also an indicator of low stellar activity.
Planetary system
Four exoplanets have been detected by TESS to be orbiting the host star TOI-700. All four exoplanets may be tidally locked to TOI-700.
Three papers describe the validation of the planetary system, the follow-up observations of TOI-700 d with the Spitzer Space Telescope and the characterization of TOI-700 d.
The composition of planets b and d is more likely rocky and the composition of planet c is more likely similar to that of Neptune.
The two inner planets might have grown faster and accreted significant gaseous envelopes, but the outer planet formed more slowly and accreted less gas. The innermost planet may later have lost its envelope due to photoevaporation. Another scenario that could explain the arrangement of densities in this system is long-term planetary migration. Planet c might have migrated inwards, but this scenario is more plausible if future studies show that planet c is significantly more massive than planet b or d.
Potentially habitable planets
TOI-700 d
TOI-700 d lies in the habitable zone. It receives 35 times more EUV photons than Earth, but also 50 times less than TRAPPIST-1 e. The host star has low stellar activity. The atmosphere of a planet with an Earth-like pressure would survive for longer than 1 Gyr. Simulations of the planet have shown that TOI-700 d is a robust candidate for a habitable world. The simulated spectral feature depths from transmission spectra and the peak flux and variations from synthesized phase curves do not exceed 10 ppm. This will likely prohibit JWST from characterizing the atmosphere of TOI-700 d.
TOI-700 e
In November 2021, a fourth possible planet, Earth-sized and receiving approximately 30% more flux from TOI-700 than Earth does from the Sun, was found at the inner edge of the habitable zone of TOI-700. In January 2023 the existence of this planet, designated 700 e, was confirmed.
Discovered in 2023, TOI-700 e is a terrestrial exoplanet that NASA claims to be an "earth-like" planet, with 95 percent of the Earth’s radius. Discovered by NASA's TESS (Transitioning Exoplanet Survey Satellite), TOI-700 e has a mass of about 0.818 Earths and takes 27.8 days to orbit once around its star. The planet is in a habitable zone distance from the M-type star TOI-700 it orbits, leading NASA scientists to believe that there is potential for liquid water on its surface. Ten percent smaller than its neighboring planet TOI-700 d, both are at a distance from their sun to be considered habitable, however, TESS requires an additional year to acquire more data about the exoplanets. Being one in only about a dozen habitable zone planets known, further research and data collection of the TOI-700 solar system is important for understanding Earth-like planets.
Near orbital resonance
The system is near (but not in) orbital resonance: from planets b to d, period ratios are approximately 5:8, 4:7, 3:4.
See also
Kepler-62f
Kepler-186f
Kepler-442b
LHS 1140 b
List of potentially habitable exoplanets
Proxima Centauri b
TRAPPIST-1e
Notes
References
External links
TESS – Official WebSite
ExoFOP TIC 150428135 TOI 700 in the Exoplanet Follow-up Observing Program website
The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System, Emily A. Gilbert et al., 3 Jan 2020
The First Habitable Zone Earth-Sized Planet From TESS II: Spitzer Confirms TOI-700 d, Joseph E. Rodriguez et al., 3 Jan 2020
The First Habitable Zone Earth-sized Planet from TESS. III: Climate States and Characterization Prospects for TOI-700 d, Gabrielle Suissa et al., 3 Jan 2020
Dorado
M-type main-sequence stars
700, TOI
J06282325-6534456
Planetary systems with four confirmed planets
Planetary transit variables | TOI-700 | [
"Astronomy"
] | 1,060 | [
"Dorado",
"Constellations"
] |
62,766,523 | https://en.wikipedia.org/wiki/TOI-700%20d | TOI-700 d is a dense, rocky, near-Earth-sized exoplanet orbiting within the habitable zone of the red dwarf TOI-700. It is located roughly away from Earth in the constellation of Dorado and is the outermost of 4 confirmed exoplanets around its star. The exoplanet is the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS).
TOI-700 d orbits its star at a distance of from its host star with an orbital period of roughly 37.4 days and has a radius of around 1.19 times that of Earth. It has been estimated that the planet receives about 88% the energy that the Earth receives from the Sun.
It was discovered in early January 2020 by the Transiting Exoplanet Survey Satellite (TESS).
Physical characteristics
Mass, radius and temperature
TOI-700 d is slightly larger than Earth with a radius of about . However, it is significantly more massive at about with a density around . The planet's high density indicates a rocky composition with a higher fraction of iron than Earth and may be explained by high-energy giant impact events during its formation.
The planet has an equilibrium temperature would be about and receives 88% as much sunlight as Earth does from the Sun. The surface temperature of TOI-700d is likely higher if it has an atmosphere. A small chance of a runaway greenhouse effect exists.
Host star
TOI-700 is a red dwarf of spectral class M that is about 40% the mass and radius, and very roughly 50% of the temperature of the Sun. The star is bright with low levels of stellar activity. Over the 11 sectors observed with TESS, the star does not show a single white-light flare. The low rotation rate is also an indicator of low stellar activity.
Orbit
TOI-700 d orbits its host star with an orbital period of 37.42 days. It has an orbital radius of about , less than half of that of Mercury to the Sun in the Solar System. It receives about 88% of Earth's sunlight from its host star.
Habitability
TOI-700 d orbits in the habitable zone of its host star. The solar wind ram pressure and intensity of the interplanetary magnetic field are expected to be similar to the Earth's, therefore retention of the planetary atmosphere is likely. The presence of an extended hydrogen/helium envelope on TOI-700c indicates the star's high energy emission was insufficient to strip its atmosphere. Therefore TOI-700d, which receives less than half the insolation as c, may have been able to maintain a secondary high mean molecular weight atmosphere even less susceptible to photoevaporation.
History and discovery
TOI-700 d was discovered by a team of astronomers led by Emily Gilbert using the Transiting Exoplanet Survey Satellite (TESS) in early January 2020. This was the first Earth-sized exoplanet in the habitable zone discovered by TESS.
See also
Kepler-62f
Kepler-186f
Kepler-442b
LHS 1140 b
List of potentially habitable exoplanets
Proxima Centauri b
TRAPPIST-1 e
References
External links
TESS – Official WebSite
NASA Exoplanet Archive System Overview page for TOI-700 d
ExoFOP TIC 150428135 TOI-700 in the Exoplanet Follow-up Observing Program website
Exoplanets discovered by Planet Hunters
Exoplanets discovered by TESS
Exoplanets discovered in 2020
Near-Earth-sized exoplanets in the habitable zone
Transiting exoplanets
Dorado
Extraterrestrial water | TOI-700 d | [
"Astronomy"
] | 761 | [
"Dorado",
"Constellations"
] |
62,766,621 | https://en.wikipedia.org/wiki/Vespamantoida%20wherleyi | Vespamantoida wherleyi is a species of praying mantis that mimics a wasp. It was discovered in 2013 at a research station near the Amazon River in northern Peru. The discovery resulted in erecting a new genus, Vespamantoida. This mantis has a red/orange colored body and black pattern. Besides the coloration, it has the body shape of and displayed walking and antenna movements similar to a wasp. This mantis is closely related to Mantoida toulgoeti as both species have a distinct foreleg synapomorphy.
References
Mantoididae
Biota of Peru
Insects described in 2019 | Vespamantoida wherleyi | [
"Biology"
] | 133 | [
"Biota by country",
"Biota of Peru"
] |
62,766,720 | https://en.wikipedia.org/wiki/Large%20Interferometer%20For%20Exoplanets | Large Interferometer For Exoplanets (LIFE) is a project started in 2017 to develop the science, technology and a roadmap for a space mission to detect and characterize the atmospheres of dozens of warm, terrestrial extrasolar planets. The current plan is for a nulling interferometer operating in the mid-infrared.
The LIFE space observatory concept is different from previous space missions, which covered a similar wavelength regime in the mid-infrared (MIR). This includes recent missions such as James Webb Space Telescope, Spitzer Space Telescope, and older missions such as ISO, IRAS, and AKARI.
Atmospheric Biosignatures
When present in sufficient quantities in the atmosphere, chemicals that are indicators of life are known as atmospheric biomarkers. The LIFE Mission is designed to observe in the mid-infrared light, where many of these molecules show spectral features.
LIFE research papers
Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
Signal simulation, signal extraction and fundamental exoplanet parameters from single epoch observations
Spectral resolution, wavelength range and sensitivity requirements based on atmospheric retrieval analyses of an exo-Earth
Diagnostic potential of a mid-infrared space-interferometer for studying Earth analogs
Ideal kernel-nulling array architectures for a space-based mid-infrared nulling interferometer
Practical implementation of a kernel-nulling beam combiner with a discussion on instrumental uncertainties and redundancy benefits
References
External links
Exoplanet science with a space-based mid-infrared nulling interferometer, Sascha P. Quanz, Jens Kammerer, Denis Defrère, Olivier Absil, Adrian M. Glauser, Daniel Kitzmann, 9 Aug 2018
See also
Astrobiology
Biosignature
Space telescopes
Exoplanet search projects
Proposed satellites | Large Interferometer For Exoplanets | [
"Astronomy"
] | 374 | [
"Astronomy projects",
"Exoplanet search projects",
"Space telescopes"
] |
62,768,627 | https://en.wikipedia.org/wiki/Kennedy%20Space%20Center%20Launch%20Complex%2048 | Launch Complex 48 (LC-48) is a multi-user launch site for small launchers and spacecraft. It is located south of Launch Complex 39A and north of Space Launch Complex 41.
The construction of LC-48 began in November 2019 but was halted in March 2020 due to the ongoing COVID-19 pandemic. Construction was resumed in June 2020, with the completion of the first pad in October 2020.
LC-48 is designed as a "clean pad" to support multiple launch systems with differing propellant needs. While initially only planned to have a single pad, the complex is capable of being expanded to two at a later date. With another pad constructed, LC-48 could support up to 104 launches per year, though actual usage is expected to be well below that.
NASA had previously constructed LC-39C within the bounds of LC-39B with the purpose of serving small launchers, but the operational constraints of sharing the site on a non-interference basis with both the Space Launch System and OmegA (now canceled) launch vehicles, along with greater interest by commercial parties than originally anticipated, led NASA to pursue the construction of a dedicated launch site for this class of vehicles.
As of August 2024, LC-48 has seen no launches, and none are currently planned from the complex. And as mentioned earlier, this is now a clean pad and thus there is no heavy infrastructure.
See also
Rocket Lab Launch Complex 1
List of Cape Canaveral and Merritt Island launch sites
Pacific Spaceport Complex – Alaska
References
Citations
Sources
External links
Exploration Ground Systems website at NASA.gov
Kennedy Space Center Master Plan at KSC.NASA.gov
Spaceport Development – Space Florida at SpaceFlorida.gov
LC-48 Completed at floridaytoday.com
Kennedy Space Center launch sites | Kennedy Space Center Launch Complex 48 | [
"Astronomy"
] | 363 | [
"Outer space stubs",
"Astronomy stubs",
"Outer space"
] |
62,769,306 | https://en.wikipedia.org/wiki/Molecular%20fragmentation%20methods | Molecular fragmentation (mass spectrometry), or molecular dissociation, occurs both in nature and in experiments. It occurs when a complete molecule is rendered into smaller fragments by some energy source, usually ionizing radiation. The resulting fragments can be far more chemically reactive than the original molecule, as in radiation therapy for cancer, and are thus a useful field of inquiry. Different molecular fragmentation methods have been built to break apart molecules, some of which are listed below.
Background
A major objective of theoretical chemistry and computational chemistry is the calculation of the energy and properties of molecules so that chemical reactivity and material properties can be understood from first principles. As a practical matter, the aim is to complement the knowledge we gain from experiments, particularly where experimental data may be incomplete or very difficult to obtain.
High-level ab-initio quantum chemistry methods are known to be an invaluable tool for understanding the structure, energy, and properties of small up to medium-sized molecules. However, the computational time for these calculations grows rapidly with increased size of molecules. One way of dealing with this problem is the molecular fragmentation approach which provides a hierarchy of approximations to the molecular electronic energy. In this approach, large molecules are divided in a systematic way to small fragments, for which high-level ab-initio calculation can be performed with acceptable computational time.
The defining characteristic of an energy-based molecular fragmentation method is that the molecule (also cluster of molecules, or liquid or solid) is broken up into a set of relatively small molecular fragments, in such a way that the electronic energy, , of the full system is given by a sum of the energies of these fragment molecules:
where is the energy of a relatively small molecular fragment,. The are simple coefficients (typically integers), and is the number of fragment molecules. Some of the methods also require a correction to the energies evaluated from the fragments. However, where necessary, this correction, , is easily computed.
Methods
Different methods have been devised to fragment molecules. Among them you can find the following energy-based methods:
Electrostatically Embedded Generalized Molecular Fractionation with Conjugate Caps (EE-GMFCC)
Generalized Energy-Based Fragmentation (GEBF)
Molecular Tailoring Approach (MTA)
Systematic Molecular Fragmentation (SMF)
Combined Fragmentation Method (CFM)
Kernel Energy Method (KEM)
Many-Overlapping-Body (MOB) Expansion
Generalized Many-Body Expansion (GMBE) Method
References
Molecular biology
Molecular physics
Molecular genetics | Molecular fragmentation methods | [
"Physics",
"Chemistry",
"Biology"
] | 506 | [
"Molecular physics",
"Biochemistry",
"Molecular biology stubs",
"Molecular genetics",
" molecular",
"nan",
"Molecular biology",
"Atomic",
"Molecular physics stubs",
" and optical physics"
] |
62,769,759 | https://en.wikipedia.org/wiki/Newman%27s%20conjecture | In mathematics, specifically in number theory, Newman's conjecture is a conjecture about the behavior of the partition function modulo any integer. Specifically, it states that for any integers and such that , the value of the partition function satisfies the congruence for infinitely many non-negative integers . It was formulated by mathematician Morris Newman in 1960. It is unsolved as of .
History
Oddmund Kolberg was probably the first to prove a related result, namely that the partition function takes both even and odd values infinitely often. The proof employed was of elementary nature and easily accessible, and was proposed as an exercise by Newman in the American Mathematical Monthly.
1 year later, in 1960, Newman proposed the conjecture and proved the cases m=5 and 13 in his original paper, and m=65 two years later.
Ken Ono, an American mathematician, made further advances by exhibiting sufficient conditions for the conjecture to hold for prime . He first showed that Newman's conjecture holds for prime if for each between 0 and , there exists a nonnegative integer such that the following holds:
He used the result, together with a computer program, to prove the conjecture for all primes less than 1000 (except 3). Ahlgren expanded on his result to show that Ono's condition is, in fact, true for all composite numbers coprime to 6.
Three years later, Ono showed that for every prime greater than 3, one of the following must hold:
Newman's conjecture holds for , or
for all nonnegative integers , and .
Using computer technology, he proved the theorem for all primes less than 200,000 (except 3).
Afterwards, Ahlgren and Boylan used Ono's criterion to extend Newman's conjecture to all primes except possibly 3. 2 years afterwards, they extended their result to all prime powers except powers of 2 or 3.
Partial progress and solved cases
The weaker statement that has at least 1 solution has been proved for all . It was formerly known as the Erdős–Ivić conjecture, named after mathematicians Paul Erdős and Aleksandar Ivić. It was settled by Ken Ono.
References
Unsolved problems in number theory
Analytic number theory | Newman's conjecture | [
"Mathematics"
] | 446 | [
"Analytic number theory",
"Unsolved problems in mathematics",
"Unsolved problems in number theory",
"Mathematical problems",
"Number theory"
] |
62,770,432 | https://en.wikipedia.org/wiki/List%20of%20astronomy%20awards | This list of astronomy awards is an index to articles about notable awards for contributions to astronomy. The list is organized by region and country of the sponsoring organization, but awards are not necessarily limited to people from that country.
Americas
Asia
Europe
Oceania
See also
Lists of awards
Lists of science and technology awards
References
Astronomy | List of astronomy awards | [
"Astronomy",
"Technology"
] | 62 | [
"Science and technology awards",
"Astronomy prizes"
] |
62,770,451 | https://en.wikipedia.org/wiki/List%20of%20agriculture%20awards | This list of agriculture awards is an index to articles about notable awards given for contributions to agriculture. Awards may be limited to people from the country in which the award is given, or may be open to worldwide contributions.
Awards
See also
Lists of awards
Lists of science and technology awards
List of cannabis competitions
References
Agriculture | List of agriculture awards | [
"Technology"
] | 63 | [
"Science and technology awards",
"Agriculture awards"
] |
62,770,467 | https://en.wikipedia.org/wiki/List%20of%20biochemistry%20awards | This list of biochemistry awards is an index to articles on notable awards for contributions to biochemistry, the study of chemical processes within and relating to living organisms. The list gives the country of the organization that gives the award, but the award may not be limited to people from that country.
Awards
See also
Lists of awards
Lists of science and technology awards
List of biology awards
List of chemistry awards
References
biochemistry | List of biochemistry awards | [
"Chemistry",
"Technology",
"Biology"
] | 80 | [
"Science and technology awards",
"Lists of science and technology awards",
"Biochemistry",
"Biochemistry awards"
] |
62,770,471 | https://en.wikipedia.org/wiki/List%20of%20biology%20awards | This list of biology awards is an index to articles about notable awards for biology. It includes a general list and lists of ecology, genetics and neuroscience awards. It excludes awards for biochemistry, biomedical science, medicine, ornithology and paleontology, which are covered by separate lists.
General awards
International
Americas
Asia
Europe
Oceania
Ecology
Genetics
Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.
Neuroscience
See also
Competitions and prizes in biotechnology
Lists of awards
Lists of science and technology awards
List of biochemistry awards
List of biomedical science awards
List of awards in bioinformatics and computational biology
List of fellows of the AACR Academy
List of medicine awards
List of ornithology awards
List of paleontology awards
References
Awards
biology | List of biology awards | [
"Technology"
] | 157 | [
"Science and technology awards",
"Biology awards",
"Lists of science and technology awards"
] |
62,770,507 | https://en.wikipedia.org/wiki/List%20of%20chemistry%20awards | This list of chemistry awards is an index to articles about notable awards for chemistry. It includes awards by the Royal Society of Chemistry, the American Chemical Society, the Society of Chemical Industry and awards by other organizations.
Awards of the Royal Society of Chemistry
The Royal Society of the United Kingdom offers a number of awards for chemistry.
Awards of the American Chemical Society
The American Chemical Society of the United States offers a number of awards related to chemistry.
Awards of the Society of Chemical Industry
The Society of Chemical Industry was established in 1881 by scientists, inventors and entrepreneurs. It offers a number of awards related to chemistry.
Other awards
See also
Lists of awards
Lists of science and technology awards
List of biochemistry awards
References
History of the chemical industry
Chemistry | List of chemistry awards | [
"Chemistry",
"Technology"
] | 147 | [
"Science and technology awards",
"Chemistry awards",
"History of the chemical industry",
"Lists of science and technology awards"
] |
62,770,515 | https://en.wikipedia.org/wiki/List%20of%20engineering%20awards | This list of engineering awards is an index to articles about notable awards for achievements in engineering. It includes aerospace engineering, chemical engineering, civil engineering, electrical engineering, electronic engineering, structural engineering and systems science awards. It excludes computer-related awards, computer science awards, industrial design awards, mechanical engineering awards, motor vehicle awards, occupational health and safety awards and space technology awards, which are covered by separate lists.
The list is organized by the region and country of the organizations that sponsor the awards, but some awards are not limited to people from that country.
International
Africa
Americas
Asia
Europe
Oceania
See also
List of computer science awards
List of computer-related awards
List of mechanical engineering awards
List of motor vehicle awards
List of space technology awards
Lists of awards
Lists of science and technology awards
References
Awards
Engineering | List of engineering awards | [
"Technology"
] | 160 | [
"Science and technology awards",
"Lists of science and technology awards",
"Engineering awards"
] |
62,770,538 | https://en.wikipedia.org/wiki/List%20of%20geology%20awards | This list of geology awards is an index to articles on notable awards for geology, an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon.
The list is organized by region and country of the organization that sponsors the award, but awards are not always restricted to people from that country.
See list of earth sciences awards for awards for earth sciences in general, and for other branches of earth science.
Americas
Canada
Chile
United States
Europe
Other regions
See also
Lists of awards
Lists of science and technology awards
List of earth sciences awards
List of geography awards
List of geophysics awards
References
Geology | List of geology awards | [
"Technology"
] | 154 | [
"Science and technology awards",
"Lists of science and technology awards"
] |
62,770,548 | https://en.wikipedia.org/wiki/List%20of%20geophysics%20awards | This list of geophysics awards is an index to articles on notable awards for contributions to geophysics, the branch of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis.
The list gives the country of the organization that sponsors the award, but the awards are not necessarily limited to people from that country.
International
Americas
Asia
Europe
See also
Lists of awards
Lists of science and technology awards
List of earth sciences awards
References
Geophysics | List of geophysics awards | [
"Technology"
] | 103 | [
"Science and technology awards",
"Lists of science and technology awards"
] |
62,770,572 | https://en.wikipedia.org/wiki/List%20of%20medicine%20awards | This list of medicine awards is an index to articles about notable awards for contributions to medicine, the science and practice of establishing the diagnosis, prognosis, treatment, and prevention of disease. The list is organized by region and country of the organization giving the award, but the awards may be available to people from around the world.
International
Americas
Asia
Europe
United Kingdom
Oceania
See also
Lists of awards
Lists of science and technology awards
List of biomedical science awards
List of psychology awards
Competitions and prizes in biotechnology
References
Medicine | List of medicine awards | [
"Technology"
] | 102 | [
"Science and technology awards",
"Medicine awards",
"Lists of science and technology awards"
] |
62,770,607 | https://en.wikipedia.org/wiki/List%20of%20physics%20awards | This list of physics awards is an index to articles about notable awards for physics.
The list is organized by region and country of the organization that gives the award. Awards are not necessarily restricted to people from the country of the award giver.
International
Americas
Asia
Europe
Oceania
See also
Lists of awards
Lists of science and technology awards
References
physics | List of physics awards | [
"Technology"
] | 68 | [
"Science and technology awards",
"Lists of science and technology awards",
"Physics awards"
] |
62,770,690 | https://en.wikipedia.org/wiki/List%20of%20environmental%20awards | This list of environmental awards is an index to articles about notable environmental awards for activities that lead to the protection of the natural environment. The list is organized by the region and country of the organization that sponsors the award. The awards may be open to the global community or limited to a particular country or field of work.
International
Americas
Asia
Europe
Oceania
See also
Lists of awards
Lists of science and technology awards
References
Environmental | List of environmental awards | [
"Technology"
] | 83 | [
"Science and technology awards",
"Lists of science and technology awards"
] |
62,771,354 | https://en.wikipedia.org/wiki/XM1100%20Scorpion | The XM1100 Scorpion, formerly known as the Intelligent Munitions System, was an anti-vehicle, smart ground munition developed by Textron Defense Systems as a safer alternative to traditional landmines. The Scorpion was originally a component of the Future Combat Systems program. It was a remotely controlled, integrated system of lethal and non-lethal munitions, ground sensors, and communication technology that could autonomously detect, track, and destroy light-wheeled to heavy-tracked vehicles.
Overview
The XM1100 Scorpion consists of a control station and a dispensing module containing the munitions. Each dispensing module can cover a minimum lethal area of 35 meters in diameter, which can be arranged to overlap the fields of other dispensing modules in order to expand the total range of surveillance. An operator supervising a single XM1100 Scorpion control station can control the activity of its corresponding dispensing module at a range of up to 3 kilometers. Unlike traditional landmines, the activity of the XM1100 Scorpion munitions can be remotely turned on or off by the operator, allowing friendly vehicles to pass through the lethal area unharmed if necessary. However, once activated, the XM1100 Scorpion can fire four anti-vehicle smart munitions into the air, releasing a guided warhead on the target. The system is also connected to the Army Battle Command Network, which allows military personnel to monitor enemy and non-combatant activity as well as prevent unwanted or unused munitions from becoming buried and forgotten.
Development
Development for the XM1100 Scorpion began as a response to the U.S. landmine policy directive of 2004, which banned the use of persistent landmines. In July 2006, the U.S. Department of Defense (DoD) awarded Textron Defense Systems with a $115 million contract for the design and development of the XM1100 Scorpion and the similarly smart XM-7 Spider landmine system as part of the DoD's Future Combat Systems (FCS) acquisition program. However, decreases in the Army's funding and the high cost of developing the munition system caused the DoD to delete the project from the FCS contract, and the XM1100 Scorpion was established as a stand-alone program in January 2007 under the supervision of the Army's Project Manager for Close Combat Systems (PM-CCS).
During its development, the XM1100 Scorpion underwent multiple performance tests and design reviews. In 2009, a test series of the system at Fort Benning, Georgia evaluated the XM1100 Scorpion's ability to identify and engage targets in urban environments. Scientists in the Survivability Lethality Analysis Directorate (SLAD) at the U.S. Army Research Laboratory (ARL) also conducted a series of live firing demonstrations at White Sands Missile Range in New Mexico and determined that the XM1100 Scorpion had achieved a “mobility kill,” demonstrating its capabilities in identifying and engaging remote-controlled, mobile targets. In 2010, successful performance testing at Yuma Proving Ground in Arizona showed that the XM1100 Scorpion had verified its operational reliability across all operational environments. However, the XM1100 Scorpion still faced termination risk due to lack of funding. In contrast, the development of the XM-7 Spider continued unhindered due to a $34 million contract awarded by Picatinny Arsenal in 2011. By 2013, the XM1100 Scorpion was integrated into the XM-7 Spider program.
See also
M7 Spider
References
Area denial weapons
Explosive weapons
Ammunition
Proposed weapons
United States Army equipment | XM1100 Scorpion | [
"Engineering"
] | 731 | [
"Area denial weapons",
"Military engineering"
] |
62,771,625 | https://en.wikipedia.org/wiki/Walter%20Burke%20Institute%20for%20Theoretical%20Physics | The Walter Burke Institute for Theoretical Physics is a research center at the California Institute of Technology focused on high-energy physics, condensed matter physics, astrophysics, general relativity, and cosmology. It was founded in 2014.
History
The Institute was founded in 2014 with grants from the Sherman Fairchild Foundation, the Gordon and Betty Moore Foundation, and funding from the California Institute of Technology itself. It had an initial endowment of over $70 million, a significant amount, particularly when placed in the context of Department of Energy funding for high-energy physics. It is named after Walter Burke, a trustee of Caltech and president of the Sherman Fairchild Foundation. Its inaugural director is Hirosi Ooguri, a string theorist.
References
See also
Institute for Theoretical Physics (disambiguation)
Center for Theoretical Physics (disambiguation)
Theoretical physics institutes
Physics research institutes
California Institute of Technology | Walter Burke Institute for Theoretical Physics | [
"Physics"
] | 181 | [
"Theoretical physics",
"Theoretical physics institutes"
] |
62,772,581 | https://en.wikipedia.org/wiki/Berkeley%20Center%20for%20Theoretical%20Physics | The Berkeley Center for Theoretical Physics (BCTP) is a research center for theoretical particle physics, cosmology, string theory and quantum gravity at the University of California at Berkeley.
About
The BCTP houses theoretical physics research at Berkeley and has close links to Lawrence Berkeley National Laboratory (LBNL). It is located in Old LeConte Hall on the Berkeley campus. Though the BCTP itself was founded at the turn of the 21st century, Berkeley has a rich history in the field of theoretical particle physics, with prominent former physicists including Manhattan project director Robert Oppenheimer; Nobel Laureates Steven Weinberg, Sheldon Glashow, and David Gross; Breakthrough Prize winners John Schwarz, Joseph Polchinski, and Nima Arkani-Hamed; Sakurai Prize winners Mary Gaillard, Leonard Susskind, and Lisa Randall; as well as Dirac Medal winners Bruno Zumino and Stanley Mandelstam. The current senior members consist of 10 UC Berkeley faculty and 4 LBNL staff members.
References
See also
Institute for Theoretical Physics (disambiguation)
Center for Theoretical Physics (disambiguation)
University of California, Berkeley
Theoretical physics institutes
Physics research institutes | Berkeley Center for Theoretical Physics | [
"Physics"
] | 242 | [
"Theoretical physics",
"Theoretical physics institutes"
] |
62,773,591 | https://en.wikipedia.org/wiki/V%20Sagittae | V Sagittae or V Sge is a cataclysmic variable in the constellation Sagitta. The system is composed of a main sequence star of about 3.3 solar masses and a white dwarf of about 0.9 solar masses; the fact that the white dwarf is less massive than its companion is highly unusual for a cataclysmic variable, and V Sge is the only super soft X-ray source nonmagnetic cataclysmic variable found so far.
Material from the larger star is accreting onto the white dwarf at an exponentially increasing rate, generating a huge stellar wind. The doubling time for the accretion rate, and hence for the system luminosity, is about years. It is predicted that the system will erupt as a nova some time between 2067 and 2099, at which point it will become one of the brightest stars in the sky.
References
Cataclysmic variable stars
Sagitta
Sagittae, V
Eclipsing binaries
21st century in outer space
2083 in science | V Sagittae | [
"Astronomy"
] | 221 | [
"Sagitta",
"Constellations"
] |
61,791,014 | https://en.wikipedia.org/wiki/Standards%20for%20Reporting%20Enzymology%20Data | Standards for Reporting Enzymology Data (STRENDA) is an initiative as part of the Minimum Information Standards which specifically focuses on the development of guidelines for reporting (describing metadata) enzymology experiments. The initiative is supported by the Beilstein Institute for the Advancement of Chemical Sciences. STRENDA establishes both publication standards for enzyme activity data and STRENDA DB, an electronic validation and storage system for enzyme activity data. Launched in 2004, the foundation of STRENDA is the result of a detailed analysis of the quality of enzymology data in written and electronic publications.
Organization
The STRENDA project is driven by 15 scientists from all over the world forming the STRENDA Commission and supporting the work with expertises in biochemistry, enzyme nomenclature, bioinformatics, systems biology, modelling, mechanistic enzymology and theoretical biology.
Reporting guidelines
The STRENDA Guidelines propose those minimum information that is needed to comprehensively report kinetic and equilibrium data from investigations of enzyme activities including corresponding experimental conditions.
This minimum information is suggested to be addressed in a scientific publication when enzymology research data is reported to ensure that data sets are comprehensively described. This allows scientists not only to review, interpret and corroborate the data but also to reuse the data for modelling and simulation of biocatalytic pathways. In addition, the guidelines support researchers making their experimental data reproducible and transparent.
As of March 2020, more than 55 international biochemistry journal included the STRENDA Guidelines in their authors' instructions as recommendations when reporting enzymology data.
The STRENDA project is registered with FAIRsharing.org and the Guidelines are part of the FAIRDOM Community standards for Systems Biology.
Applications
STRENDA DB
STRENDA DB is a web-based storage and search platform that has incorporated the Guidelines and automatically checks the submitted data on compliance with the STRENDA Guidelines thus ensuring that the manuscript data sets are complete and valid. A valid data set is awarded a STRENDA Registry Number (SRN) and a fact sheet (PDF) is created containing all submitted data. Each dataset is registered at Datacite and assigned a DOI to refer and track the data. After the publication of the manuscript in a peer-reviewed journal the data in STRENDA DB are made open accessible.
STRENDA DB is a repository recommended by re3data and OpenDOAR. It is harvested by OpenAIRE.
The database service is recommended in the authors' instructions of more than 10 biochemistry journals, including Nature, The Journal of Biological Chemistry, eLife, and PLoS. It has been referred as a standard tool for the validation and storage of enzyme kinetics data in multifold publications
A recent study examining eleven publications, including Supporting Information, from two leading journals revealed that at least one omission was found in every one of these papers. The authors concluded that using STRENDA DB in the current version would ensure that about 80% auf the relevant information would be made available.
Data Management
STRENDA DB is considered a tool for research data management by the research community (e.g. EU project CARBAFIN).
References
External References
Record in FAIRSharing.org for STRENDA DB, https://fairsharing.org/FAIRsharing.ekj9zx
Biochemistry
Proteins
Enzymes
Standards
Biological databases | Standards for Reporting Enzymology Data | [
"Chemistry",
"Biology"
] | 678 | [
"Biomolecules by chemical classification",
"Bioinformatics",
"nan",
"Molecular biology",
"Biochemistry",
"Proteins",
"Biological databases"
] |
61,791,166 | https://en.wikipedia.org/wiki/Generation%20expansion%20planning | Generation expansion planning (also known as GEP) is finding an optimal solution for the planning problem in which the installation of new generation units satisfies both technical and financial limits. GEP is a challenging problem because of the large scale, long-term and nonlinear nature of generation unit size. Due to lack of information, companies have to solve this problem in a risky environment because the competition between generation companies for maximizing their benefit make them to conceal their strategies. Under such an ambiguous condition, various nonlinear solutions have been proposed to solve this sophisticated problem. These solutions are based on different strategies including: game theory, two-level game model, multi-agent system, genetic algorithm, particle swarm optimization and so forth.
See also
Demand response
power system
References
Electric power generation
Planning
Power engineering | Generation expansion planning | [
"Engineering"
] | 159 | [
"Power engineering",
"Electrical engineering",
"Energy engineering"
] |
61,791,659 | https://en.wikipedia.org/wiki/Almadena%20Chtchelkanova | Almadena Yurevna Chtchelkanova is a Russian-American scientist. She is a program director in the Division of Computing and Communication Foundations at the National Science Foundation.
Education
Chtchelkanova completed a Ph.D. in physics from Moscow State University in 1988. In 1996, she earned a M.A. in the department of computer sciences at University of Texas at Austin. Her master's thesis was titled The application of object-oriented analysis to sockets system calls library testing. James C. Browne was her advisor.
Career
She worked as a senior scientist for Strategic Analysis, Inc. which provided support to DARPA. She provided support and oversight of the Spintronics, Quantum Information Science and Technology (QuIST) and Molecular Observation and Imaging programs. She worked at the United States Naval Research Laboratory for 4 years in the laboratory for computational physics and fluid dynamics. Chtchelkanova joined the National Science Foundation in 2005. She is a program director in the Division of Computing and Communication Foundations and oversees programs involving high performance computing.
References
External links
United States National Science Foundation officials
University of Texas at Austin College of Natural Sciences alumni
Moscow State University alumni
20th-century Russian women scientists
21st-century American women scientists
Russian women computer scientists
Women physicists
Computational physicists
21st-century American physicists
20th-century Russian physicists
Year of birth missing (living people)
Living people | Almadena Chtchelkanova | [
"Physics"
] | 282 | [
"Computational physicists",
"Computational physics"
] |
61,793,228 | https://en.wikipedia.org/wiki/Individualized%20cancer%20immunotherapy | Individualized cancer immunotherapy, also referred to as individualized immuno-oncology, is a novel concept for therapeutic cancer vaccines that are truly personalized to a single individual.
The human immune system is generally able to recognize and fight cancer cells. However, this ability is usually insufficient and the cancer continues to spread. Cancer immunotherapy is based on harnessing and potentiating the ability of the immune system to fight cancer.
Each tumor has its own individual genetic fingerprint, the mutanome, that includes numerous genetic alterations. As opposed to a preformed drug, individualized cancer vaccination is a therapy that targets specific cancer mutations of the individual patient's tumor. The production of vaccines tailored to match a person's individual constellation of cancer mutations has become a new field of research.
The concept of individualized cancer immunotherapy aims to identify individual mutations in the tumor of a patient, that are crucial for the proliferation, survival or metastasis of tumor cells. For this purpose, the individual genetic blueprint of the tumor is decrypted by sequencing and, using this blueprint as a template, a synthetic vaccine tailored to the tumor of the individual patient is prepared. This vaccine is designed to control and train the body's immune system to fight the cancer.
Background
Cancer is characterized by an accumulation of genetic alterations. A tumor may acquire up to thousands of different somatic mutations during the process of initiation and progression. A smaller number of cancer mutations interfere with normal cell regulation and help to drive cancer growth.
Somatic mutations in the tumor genome can cause tumors to express mutant proteins (neoantigens) that are recognized by autologous T cells as foreign and constitute cancer vaccine targets. Tumor Mutational Burden (TMB, the number of mutations within a targeted genetic region in the cancerous cell's DNA) have been thus suggested to correlate with patient survival post immunotherapy, although the findings are disputed.
Such neoantigens are specifically expressed by tumor tissue and are not found on the surface of normal cells. They can upregulate tumor-specific T cells in patients without killing normal cells.
T cells are key effectors of anticancer immunity. They are capable of distinguishing tumor cells from normal ones by recognizing HLA-bound cancer-specific peptides. A requirement for the recognition of neoantigens by the immune system is that the neoantigens and their antigenic determinants, the neoepitopes, are processed and presented by human leukocyte antigen (HLA) molecules. These molecules may be recognized by CD8+ cytotoxic T lymphocytes as foreign neoepitopes and, with the help of CD4+ T lymphocytes, trigger an immune response leading to tumor-specific killing. CD8+ T cells are specialized for direct tumor cell killing. CD4+ T cells can interact with antigen-presenting cells such as dendritic cells to recruit other immune cells or stimulate effector cells.
Most cancer neoantigens in humans arise from unique mutations. A patient's cancer is intra- as well as interlesionally heterogeneous and changes its composition over time. Each patient has an individual mutational signature (mutanome), and only a very small portion of the mutations are shared between patients. A concept is therefore that an immunotherapy directed at neoantigens needs to be individualized.
The development of sequencing technology has improved the accuracy of identification and localization of neoantigens. With the advent of next-generation sequencing (NGS), it has become possible to systematically predict cancer neoantigens for individual patients.
Preclinical research
In animal models, several independent studies have shown that vaccines consisting of computationally predicted neoepitopes mediated anti-tumor activity in mice.
First-in-human clinical trials
The translation of individualized neoepitope vaccines into clinical oncology is under investigation. Formats under consideration for individualized vaccines are synthetic peptides, messenger RNA, DNA plasmids, viral vectors, engineered bacteria, and antigen-loaded dendritic cells.
Patients with melanoma
In 2015, a first step towards individualized neoantigen vaccination was achieved by treating three melanoma patients with autologous dendritic cells loaded with a personalized mixture of seven peptides (neoantigens) that were predicted to bind to human leukocyte antigens (HLA). The neoantigen-loaded dendritic cells were cultured in vitro for autologous transfusion. Results showed that the vaccine enhanced the existing immune response and elicited a neoantigen-specific T cell response that was not detected prior to injection.
Sahin et al. were the first to identify suitable neoantigens using next generation sequencing (NGS) and used them to produce customized RNA vaccines capable of encoding these neoantigens. A total of 13 patients with melanoma received the RNA vaccine, eight of which had no tumor development during the follow-up. Immune surveillance analysis of peripheral blood mononuclear cells (PBMCs) in patients demonstrated that the RNA vaccines expanded preexisting T cells and induced de novo T cell responses against neoepitopes not recognized prior to vaccination.
Another study group (Ott et al.) identified neoantigens in six melanoma patients and used them to create a customized vaccine for each patient with long peptides representing up to 20 mutations per patient. After surgical resection of the tumor, the vaccine was injected. The results showed that the tumor did not reappear in four patients during an observation period of 32 months after vaccination.
Patients with glioblastoma
Hilf et al. administered individualized neoantigen vaccines to 15 patients with glioblastoma. The vaccine triggered T cell immune responses to the predicted neoantigens.
Keskin et al. investigated individualized neoantigen vaccines in eight glioblastoma patients after surgical resection and conventional radiotherapy. The study group observed that the vaccine increased the number of tumor-infiltrating T cells that migrated from the peripheral blood into the brain.
Manufacturing process of mutation-based vaccines
Individualized cancer vaccines typically consist of multiple predicted neoepitopes. The manufacturing process involves several steps.
Tumor biopsies and healthy tissue (e.g., peripheral blood cells) of a patient diagnosed with cancer are examined by NGS. Tumor-specific mutations in protein-coding genes are then identified by comparison of sequences from tumor and normal DNA. Computational tools classify these mutations for the highest likelihood of immunogenicity, that is, for the predicted expression and binding affinity of neoepitopes on HLA molecules. The top rankers are then used for the production of the vaccine.
The intended output is an on-demand vaccine with a unique composition tailored to the patient's individual cancer mutanome.
Individualized NeoAntigen Specific Immunotherapy (iNeST)
The research approach to mobilize an immune response tailored to the individual tumor of a patient is also referred to as individualized neoantigen-specific immunotherapy (iNeST).
iNeST is based on the specific tumor mutations (neoantigens) of a single patient, with the aim of triggering high-affinity immune responses of T cells to the individual patient-specific cancer. The development of iNeST is driven by biotech companies
References
Medical genetics
Biotechnology
Applied genetics
Genomics
Vaccines
Cancer vaccines | Individualized cancer immunotherapy | [
"Biology"
] | 1,555 | [
"nan",
"Vaccination",
"Vaccines",
"Biotechnology"
] |
61,793,916 | https://en.wikipedia.org/wiki/Strip%20packing%20problem | The strip packing problem is a 2-dimensional geometric minimization problem.
Given a set of axis-aligned rectangles and a strip of bounded width and infinite height, determine an overlapping-free packing of the rectangles into the strip, minimizing its height.
This problem is a cutting and packing problem and is classified as an Open Dimension Problem according to Wäscher et al.
This problem arises in the area of scheduling, where it models jobs that require a contiguous portion of the memory over a given time period. Another example is the area of industrial manufacturing, where rectangular pieces need to be cut out of a sheet of material (e.g., cloth or paper) that has a fixed width but infinite length, and one wants to minimize the wasted material.
This problem was first studied in 1980. It is strongly-NP hard and there exists no polynomial-time approximation algorithm with a ratio smaller than unless . However, the best approximation ratio achieved so far (by a polynomial time algorithm by Harren et al.) is , imposing an open question of whether there is an algorithm with approximation ratio .
Definition
An instance of the strip packing problem consists of a strip with width and infinite height, as well as a set of rectangular items.
Each item has a width and a height .
A packing of the items is a mapping that maps each lower-left corner of an item to a position inside the strip.
An inner point of a placed item is a point from the set .
Two (placed) items overlap if they share an inner point.
The height of the packing is defined as .
The objective is to find an overlapping-free packing of the items inside the strip while minimizing the height of the packing.
This definition is used for all polynomial time algorithms. For pseudo-polynomial time and FPT-algorithms, the definition is slightly changed for the simplification of notation. In this case, all appearing sizes are integral. Especially the width of the strip is given by an arbitrary integer number larger than 1. Note that these two definitions are equivalent.
Variants
There are several variants of the strip packing problem that have been studied. These variants concern the objects' geometry, the problem's dimension, the rotateability of the items, and the structure of the packing.
Geometry: In the standard variant of this problem, the set of given items consists of rectangles.
In an often considered subcase, all the items have to be squares. This variant was already considered in the first paper about strip packing.
Additionally, variants where the shapes are circular or even irregular have been studied. In the latter case, it is referred to as irregular strip packing.
Dimension:
When not mentioned differently, the strip packing problem is a 2-dimensional problem. However, it also has been studied in three or even more dimensions. In this case, the objects are hyperrectangles, and the strip is open-ended in one dimension and bounded in the residual ones.
Rotation: In the classical strip packing problem, the items are not allowed to be rotated. However, variants have been studied where rotating by 90 degrees or even an arbitrary angle is allowed.
Structure:
In the general strip packing problem, the structure of the packing is irrelevant.
However, there are applications that have explicit requirements on the structure of the packing. One of these requirements is to be able to cut the items from the strip by horizontal or vertical edge-to-edge cuts.
Packings that allow this kind of cutting are called guillotine packing.
Hardness
The strip packing problem contains the bin packing problem as a special case when all the items have the same height 1.
For this reason, it is strongly NP-hard, and there can be no polynomial time approximation algorithm that has an approximation ratio smaller than unless .
Furthermore, unless , there cannot be a pseudo-polynomial time algorithm that has an approximation ratio smaller than , which can be proven by a reduction from the strongly NP-complete 3-partition problem.
Note that both lower bounds and also hold for the case that a rotation of the items by 90 degrees is allowed.
Additionally, it was proven by Ashok et al. that strip packing is W[1]-hard when parameterized by the height of the optimal packing.
Properties of optimal solutions
There are two trivial lower bounds on optimal solutions.
The first is the height of the largest item.
Define .
Then it holds that
.
Another lower bound is given by the total area of the items.
Define then it holds that
.
The following two lower bounds take notice of the fact that certain items cannot be placed next to each other in the strip, and can be computed in .
For the first lower bound assume that the items are sorted by non-increasing height. Define . For each define the first index such that . Then it holds that
.
For the second lower bound, partition the set of items into three sets. Let and define , , and . Then it holds that
, where for each .
On the other hand, Steinberg has shown that the height of an optimal solution can be upper bounded by
More precisely he showed that given a and a then the items can be placed inside a box with width and height if
, where .
Polynomial time approximation algorithms
Since this problem is NP-hard, approximation algorithms have been studied for this problem.
Most of the heuristic approaches have an approximation ratio between and .
Finding an algorithm with a ratio below seems complicated, and
the complexity of the corresponding algorithms increases regarding their running time and their descriptions.
The smallest approximation ratio achieved so far is .
Bottom-up left-justified (BL)
This algorithm was first described by Baker et al. It works as follows:
Let be a sequence of rectangular items.
The algorithm iterates the sequence in the given order.
For each considered item , it searches for the bottom-most position to place it and then shifts it as far to the left as possible.
Hence, it places at the bottom-most left-most possible coordinate in the strip.
This algorithm has the following properties:
The approximation ratio of this algorithm cannot be bounded by a constant. More precisely they showed that for each there exists a list of rectangular items ordered by increasing width such that , where is the height of the packing created by the BL algorithm and is the height of the optimal solution for .
If the items are ordered by decreasing widths, then .
If the item are all squares and are ordered by decreasing widths, then .
For any , there exists a list of rectangles ordered by decreasing widths such that .
For any , there exists a list of squares ordered by decreasing widths such that .
For each , there exists an instance containing only squares where each order of the squares has a ratio of , i.e., there exist instances where BL does not find the optimum even when iterating all possible orders of the items. In 2024 this lower bound has been improved by Hougardy and Zondervan to .
Next-fit decreasing-height (NFDH)
This algorithm was first described by Coffman et al. in 1980 and works as follows:
Let be the given set of rectangular items.
First, the algorithm sorts the items by order of nonincreasing height.
Then, starting at position , the algorithm places the items next to each other in the strip until the next item will overlap the right border of the strip.
At this point, the algorithm defines a new level at the top of the tallest item in the current level and places the items next to each other in this new level.
This algorithm has the following properties:
The running time can be bounded by and if the items are already sorted even by .
For every set of items , it produces a packing of height , where is the largest height of an item in .
For every there exists a set of rectangles such that
The packing generated is a guillotine packing. This means the items can be obtained through a sequence of horizontal or vertical edge-to-edge cuts.
First-fit decreasing-height (FFDH)
This algorithm, first described by Coffman et al. in 1980, works similar to the NFDH algorithm.
However, when placing the next item, the algorithm scans the levels from bottom to top and places the item in the first level on which it will fit.
A new level is only opened if the item does not fit in any previous ones.
This algorithm has the following properties:
The running time can be bounded by , since there are at most levels.
For every set of items it produces a packing of height , where is the largest height of an item in .
Let . For any set of items and strip with width such that for each , it holds that . Furthermore, for each , there exists such a set of items with .
If all the items in are squares, it holds that . Furthermore, for each , there exists a set of squares such that .
The packing generated is a guillotine packing. This means the items can be obtained through a sequence of horizontal or vertical edge-to-edge cuts.
The split-fit algorithm (SF)
This algorithm was first described by Coffman et al.
For a given set of items and strip with width , it works as follows:
Determinate , the largest integer such that the given rectangles have width or less.
Divide into two sets and , such that contains all the items with a width while contains all the items with .
Order and by nonincreasing height.
Pack the items in with the FFDH algorithm.
Reorder the levels/shelves constructed by FFDH such that all the shelves with a total width larger than are below the more narrow ones.
This leaves a rectangular area of with , next to more narrow levels/shelves, that contains no item.
Use the FFDH algorithm to pack the items in using the area as well.
This algorithm has the following properties:
For every set of items and the corresponding , it holds that . Note that for , it holds that
For each , there is a set of items such that .
Sleator's algorithm
For a given set of items and strip with width , it works as follows:
Find all the items with a width larger than and stack them at the bottom of the strip (in random order). Call the total height of these items . All the other items will be placed above .
Sort all the remaining items in nonincreasing order of height. The items will be placed in this order.
Consider the horizontal line at as a shelf. The algorithm places the items on this shelf in nonincreasing order of height until no item is left or the next one does not fit.
Draw a vertical line at , which cuts the strip into two equal halves.
Let be the highest point covered by any item in the left half and the corresponding point on the right half. Draw two horizontal line segments of length at and across the left and the right half of the strip. These two lines build new shelves on which the algorithm will place the items, as in step 3. Choose the half which has the lower shelf and place the items on this shelf until no other item fits. Repeat this step until no item is left.
This algorithm has the following properties:
The running time can be bounded by and if the items are already sorted even by .
For every set of items it produces a packing of height , where is the largest height of an item in .
The split algorithm (SP)
This algorithm is an extension of Sleator's approach and was first described by Golan.
It places the items in nonincreasing order of width.
The intuitive idea is to split the strip into sub-strips while placing some items.
Whenever possible, the algorithm places the current item side-by-side of an already placed item .
In this case, it splits the corresponding sub-strip into two pieces: one containing the first item and the other containing the current item .
If this is not possible, it places on top of an already placed item and does not split the sub-strip.
This algorithm creates a set S of sub-strips. For each sub-strip s ∈ S we know its lower left corner s.xposition and s.yposition, its width s.width, the horizontal lines parallel to the upper and lower border of the item placed last inside this sub-strip s.upper and s.lower, as well as the width of it s.itemWidth.
function Split Algorithm (SP) is
input: items I, width of the strip W
output: A packing of the items
Sort I in nonincreasing order of widths;
Define empty list S of sub-strips;
Define a new sub-strip s with s.xposition = 0, s.yposition = 0, s.width = W, s.lower = 0, s.upper = 0, s.itemWidth = W;
Add s to S;
while I not empty do
i := I.pop(); Removes widest item from I
Define new list S_2 containing all the substrips with s.width - s.itemWidth ≥ i.width;
S_2 contains all sub-strips where i fits next to the already placed item
if S_2 is empty then
In this case, place the item on top of another one.
Find the sub-strip s in S with smallest s.upper; i.e. the least filled sub-strip
Place i at position (s.xposition, s.upper);
Update s: s.lower := s.upper; s.upper := s.upper+i.height; s.itemWidth := i.width;
else
In this case, place the item next to another one at the same level and split the corresponding sub-strip at this position.
Find s ∈ S_2 with the smallest s.lower;
Place i at position (s.xposition + s.itemWidth, s.lower);
Remove s from S;
Define two new sub-strips s1 and s2 with
s1.xposition = s.xposition, s1.yposition = s.upper, s1.width = s.itemWidth, s1.lower = s.upper, s1.upper = s.upper, s1.itemWidth = s.itemWidth;
s2.xposition = s.xposition+s.itemWidth, s2.yposition = s.lower, s2.width = s.width - s.itemWidth, s2.lower = s.lower, s2.upper = s.lower + i.height, s2.itemWidth = i.width;
S.add(s1,s2);
return
end function
This algorithm has the following properties:
The running time can be bounded by since the number of substrips is bounded by .
For any set of items it holds that .
For any , there exists a set of items such that .
For any and , there exists a set of items such that .
Reverse-fit (RF)
This algorithm was first described by Schiermeyer.
The description of this algorithm needs some additional notation.
For a placed item , its lower left corner is denoted by and its upper right corner by .
Given a set of items and a strip of width , it works as follows:
Stack all the rectangles of width greater than on top of each other (in random order) at the bottom of the strip. Denote by the height of this stack. All other items will be packed above .
Sort the remaining items in order of nonincreasing height and consider the items in this order in the following steps. Let be the height of the tallest of these remaining items.
Place the items one by one left aligned on a shelf defined by until no other item fit on this shelf or there is no item left. Call this shelf the first level.
Let be the height of the tallest unpacked item. Define a new shelf at . The algorithm will fill this shelf from right to left, aligning the items to the right, such that the items touch this shelf with their top. Call this shelf the second reverse-level.
Place the items into the two shelves due to First-Fit, i.e., placing the items in the first level where they fit and in the second one otherwise. Proceed until there are no items left, or the total width of the items in the second shelf is at least .
Shift the second reverse-level down until an item from it touches an item from the first level. Define as the new vertical position of the shifted shelf. Let and be the right most pair of touching items with placed on the first level and on the second reverse-level. Define .
If then is the last rectangle placed in the second reverse-level. Shift all the other items from this level further down (all the same amount) until the first one touches an item from the first level. Again the algorithm determines the rightmost pair of touching items and . Define as the amount by which the shelf was shifted down.
If then shift to the left until it touches another item or the border of the strip. Define the third level at the top of .
If then shift define the third level at the top of . Place left-aligned in this third level, such that it touches an item from the first level on its left.
Continue packing the items using the First-Fit heuristic. Each following level (starting at level three) is defined by a horizontal line through the top of the largest item on the previous level. Note that the first item placed in the next level might not touch the border of the strip with their left side, but an item from the first level or the item .
This algorithm has the following properties:
The running time can be bounded by , since there are at most levels.
For every set of items it produces a packing of height .
Steinberg's algorithm (ST)
Steinbergs algorithm is a recursive one. Given a set of rectangular items and a rectangular target region with width and height , it proposes four reduction rules, that place some of the items and leaves a smaller rectangular region with the same properties as before regarding of the residual items.
Consider the following notations: Given a set of items we denote by the tallest item height in , the largest item width appearing in and by the total area of these items.
Steinbergs shows that if
, , and , where ,
then all the items can be placed inside the target region of size .
Each reduction rule will produce a smaller target area and a subset of items that have to be placed. When the condition from above holds before the procedure started, then the created subproblem will have this property as well.
Procedure 1: It can be applied if .
Find all the items with width and remove them from .
Sort them by nonincreasing width and place them left-aligned at the bottom of the target region. Let be their total height.
Find all the items with width . Remove them from and place them in a new set .
If is empty, define the new target region as the area above , i.e. it has height and width . Solve the problem consisting of this new target region and the reduced set of items with one of the procedures.
If is not empty, sort it by nonincreasing height and place the items right allinged one by one in the upper right corner of the target area. Let be the total width of these items. Define a new target area with width and height in the upper left corner. Solve the problem consisting of this new target region and the reduced set of items with one of the procedures.
Procedure 2: It can be applied if the following conditions hold: , , and there exist two different items with , , , and .
Find and and remove them from .
Place the wider one in the lower-left corner of the target area and the more narrow one left-aligned on the top of the first.
Define a new target area on the right of these both items, such that it has the width and height .
Place the residual items in into the new target area using one of the procedures.
Procedure 3: It can be applied if the following conditions hold: , , , and when sorting the items by decreasing width there exist an index such that when defining as the first items it holds that
as well as
Set .
Define two new rectangular target areas one at the lower-left corner of the original one with height and width and the other left of it with height and width .
Use one of the procedures to place the items in into the first new target area and the items in into the second one.
Note that procedures 1 to 3 have a symmetric version when swapping the height and the width of the items and the target region.
Procedure 4: It can be applied if the following conditions hold: , , and there exists an item such that .
Place the item in the lower-left corner of the target area and remove it from .
Define a new target area right of this item such that it has the width and height and place the residual items inside this area using one of the procedures.
This algorithm has the following properties:
The running time can be bounded by .
For every set of items it produces a packing of height .
Pseudo-polynomial time approximation algorithms
To improve upon the lower bound of for polynomial-time algorithms, pseudo-polynomial time algorithms for the strip packing problem have been considered.
When considering this type of algorithms, all the sizes of the items and the strip are given as integrals. Furthermore, the width of the strip is allowed to appear polynomially in the running time.
Note that this is no longer considered as a polynomial running time since, in the given instance, the width of the strip needs an encoding size of .
The pseudo-polynomial time algorithms that have been developed mostly use the same approach. It is shown that each optimal solution can be simplified and transformed into one that has one of a constant number of structures. The algorithm then iterates all these structures and places the items inside using linear and dynamic programming. The best ratio accomplished so far is . while there cannot be a pseudo-polynomial time algorithm with ratio better than unless
Online algorithms
In the online variant of strip packing, the items arrive over time. When an item arrives, it has to be placed immediately before the next item is known. There are two types of online algorithms that have been considered. In the first variant, it is not allowed to alter the packing once an item is placed. In the second, items may be repacked when another item arrives. This variant is called the migration model.
The quality of an online algorithm is measured by the (absolute) competitive ratio
,
where corresponds to the solution generated by the online algorithm and corresponds to the size of the optimal solution.
In addition to the absolute competitive ratio, the asymptotic competitive ratio of online algorithms has been studied. For instances with it is defined as
.
Note that all the instances can be scaled such that .
The framework of Han et al. is applicable in the online setting if the online bin packing
algorithm belongs to the class Super Harmonic. Thus, Seiden's online bin packing algorithm
Harmonic++ implies an algorithm for online strip packing with asymptotic ratio 1.58889.
References
Mathematical analysis
Packing problems
Strongly NP-complete problems | Strip packing problem | [
"Mathematics"
] | 4,786 | [
"Mathematical analysis",
"Mathematical problems",
"Packing problems"
] |
61,795,792 | https://en.wikipedia.org/wiki/Hand%E2%80%93eye%20calibration%20problem | In robotics and mathematics, the hand–eye calibration problem (also called the robot–sensor or robot–world calibration problem) is the problem of determining the transformation between a robot end-effector and a sensor or sensors (camera or laser scanner) or between a robot base and the world coordinate system. It is conceptually analogous to biological hand–eye coordination (hence the name). It takes the form of , where A and B are two systems, usually a robot base and a camera, and and are unknown transformation matrices. A highly studied special case of the problem occurs where , taking the form of the problem . Solutions to the problem take the forms of several types of methods, including separable closed-form solutions, simultaneous closed-form solutions, and iterative solutions. The covariance of in the equation can be calculated for any randomly perturbed matrices and .
The problem is an important part of robot calibration, with efficiency and accuracy of the solutions determining the speed accuracy of the calibrations of robots.
Methods
Many different methods and solutions developed to solve the problem, broadly defined as either separable, simultaneous solutions. Each type of solution has specific advantages and disadvantages as well as formulations and applications to the problem. A common theme throughout all of the methods is the common use of quaternions to represent rotations.
Separable solutions
Given the equation , it is possible to decompose the equation into a purely rotational and translational part; methods utilizing this are referred to as separable methods. Where represents a 3×3 rotation matrix and a 3×1 translation vector, the equation can be broken into two parts:
The second equation becomes linear if is known. As such, the most frequent approach is to solve for and using the first equation, then using to solve for the variables in the second equation. Rotation is represented using quaternions, allowing for a linear solution to be found. While separable methods are useful, any error in the estimation for the rotation matrices is compounded when being applied to the translation vector. Other solutions avoid this problem.
Simultaneous solutions
Simultaneous solutions are based on solving for both and at the same time (rather than basing the solution of one part off of the other as in separable solutions), propagation of error is significantly reduced. By formulating the matrices as dual quaternions, it is possible to get a linear equation by which is solvable in a linear format. An alternative way applies the least-squares method to the Kronecker product of the matrices . As confirmed by experimental results, simultaneous solutions have less error than separable quaternion solutions.
Iterative solutions
Iterative solutions are another method used to solve the problem of error propagation. One example of an iterative solution is a program based on minimizing . As the program iterates, it will converge on a solution to independent to the initial robot orientation of . Solutions can also be two-step iterative processes, and like simultaneous solutions can also decompose the equations into dual quaternions. However, while iterative solutions to the problem are generally simultaneous and accurate, they can be computationally taxing to carry out and may not always converge on the optimal solution.
The AX=XB case
The matrix equation , where is unknown, has an infinitive number of solutions that can be easily studied by a geometrical approach. To find it is necessary to consider a simultaneous set of 2 equations and ; the matrices have to be dermined by experiments to be performed in an optimized way.
The 2D laser profile scanner case
where represents the unknown coordinate of the point in the robot base system, represent the known relationship between the robot base system and end-effector, are the unknown relationship between the end-effector and the scanner, and is the known coordinate of the point in the local scanner system. Methods are as follows,
Straight edges
There is a method using straight edges for hand-eye calibration.
References
Robot control | Hand–eye calibration problem | [
"Engineering"
] | 816 | [
"Robotics engineering",
"Robot control"
] |
67,082,723 | https://en.wikipedia.org/wiki/Rhodium%28III%29%20nitrate | Rhodium(III) nitrate is a inorganic compound, a salt of rhodium and nitric acid with the formula Rh(NO3)3. This anhydrous complex has been the subject of theoretical analysis but has not been isolated. However, a dihydrate and an aqueous solution are known with similar stoichiometry; they contain various hexacoordinated rhodium(III) aqua and nitrate complexes. A number of other rhodium nitrates have been characterized by X-ray crystallography: Rb4[trans-[Rh(H2O)2(NO3)4][Rh(NO3)6] and Cs2[-[Rh(NO3)5]. Rhodium nitrates are of interest because nuclear wastes, which contain rhodium, are recycled by dissolution in nitric acid.
Uses
Rhodium(III) nitrate is used as a precursor to synthesize rhodium.
References
Rhodium(III) compounds
Nitrates
Hypothetical chemical compounds
Hydrates | Rhodium(III) nitrate | [
"Chemistry"
] | 224 | [
"Inorganic compounds",
"Hydrates",
"Nitrates",
"Salts",
"Inorganic compound stubs",
"Oxidizing agents",
"Hypotheses in chemistry",
"Theoretical chemistry",
"Hypothetical chemical compounds"
] |
67,082,792 | https://en.wikipedia.org/wiki/Chemical%20Workers%27%20Industrial%20Union | The Chemical Workers' Industrial Union (CWIU) was a trade union representing workers in chemical and related industries in South Africa.
History
The union was founded on 24 November 1974, on the initiative of the General Factory Workers' Benefit Fund. By the end of the year, it had about 1,000 members and had affiliated to the Trade Union Advisory and Co-ordinating Council. It developed a strategy of focusing on mass organisation in a small number of factories, mostly Revertex and Henkel. It declined to only 500 members in 1979, but that year became a founding affiliate of the Federation of South African Trade Unions. It expanded into the Transvaal in 1980, and by 1981 had grown to 4,200 members.
The union absorbed the Glass and Allied Workers' Union in December 1982. It was a founding affiliate of the Congress of South African Trade Unions in 1985, and by 1986 had grown further, to 29,859 members. In 1999, it merged with the Paper, Printing and Allied Workers' Union, to form the Chemical, Energy, Paper, Printing, Wood and Allied Workers' Union.
General Secretaries
1970s: Nombuso Dlamini
1980s: Rod Crompton
1991: Muzi Buthelezi
References
Chemical industry
Trade unions established in 1974
Trade unions disestablished in 1999
Trade unions in South Africa
1974 establishments in South Africa
1999 disestablishments in South Africa | Chemical Workers' Industrial Union | [
"Chemistry"
] | 284 | [
"nan"
] |
67,085,886 | https://en.wikipedia.org/wiki/Selenide%20borate | Selenide borates, officially known as borate selenides, are chemical mixed anion compounds that contain any kind of borate and selenide ions. They are distinct from selenoborates in which selenium atoms replace oxygen in borates. There are also analogous borate sulfides, with sulfur ions instead of selenium.
List
References
Borates
Selenides
Mixed anion compounds | Selenide borate | [
"Physics",
"Chemistry"
] | 87 | [
"Ions",
"Matter",
"Mixed anion compounds"
] |
67,088,019 | https://en.wikipedia.org/wiki/Saint%20Paul%27s%20Well | Saint Paul's Well is a water well in Tarsus, Turkey, claimed to have belonged to Paul the Apostle (then named Saul) when he lived there. The well, along with Saint Paul's Church, is on the UNESCO Tentative list of World Heritage Sites in Turkey and is under the control of the public authorities.
Tarsus, currently a part of Mersin Province, was an important Roman city in the first century. The ruins of Saint Paul's house, as well as the still-serviceable well in the old quarters of Tarsus, were unearthed during a rescue excavation in 1999. Restored old houses and the ancient road in Tarsus are located nearby.
The well, made of mostly rectangular-cut stone, measures in diameter at the top and has a depth of .
References
Tarsus, Mersin
Paul the Apostle
Water wells
Archaeological sites of classical Anatolia
Archaeological sites in Mersin Province, Turkey
World Heritage Tentative List for Turkey
Christian pilgrimage sites | Saint Paul's Well | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 194 | [
"Hydrology",
"Water wells",
"Environmental engineering"
] |
67,090,228 | https://en.wikipedia.org/wiki/Threshold%20dose | Threshold dose is the minimum dose of drug that triggers minimal detectable biological effect in an animal. At extremely low doses, biological responses are absent for some of the drugs. The increase in dose above threshold dose induces an increase in the percentage of biological responses. Several benchmarks have been established to describe the effects of a particular dose of drug in a particular species, such as NOEL(no-observed-effect-level), NOAEL(no-observed-adverse-effect-level) and LOAEL(lowest-observed-adverse-effect-level). They are established by reviewing the available studies and animal studies. The application of threshold dose in risk assessment safeguards the participants in human clinical trials and evaluates the risks of chronic exposure to certain substances. However, the nature of animal studies also limits the applicability of experimental results in the human population and its significance in evaluating potential risk of certain substances. In toxicology, there are some other safety factors including LD50, LC50 and EC50.
Dose levels
Threshold dose is a dose of drug barely adequate to produce a biological effect in an animal. In dose-response assessment, the term ‘threshold dose’ is refined into several terminologies, such as NOEL, NOAEL, and LOAEL. They define the limits of doses resulting in biological responses or toxic effects. Common responses are alterations in structures, growth, development and average lifespan of the treated group of organisms. The changes are found by comparing the observations between the treated and control groups. Both groups are of the same species and have the same environment of exposure in the trial. The only difference is that the treated group receives the experimental substance while the control group does not.
For the drugs administered by oral and dermal route, the units of threshold dose are mg/kg body-weight/day (dose of the drug in mg per body weight in kg per day) or ppm (parts per million), while the threshold dose of drugs by inhalation delivery has the unit of mg/L 6h/day (amount of drug in mg in 1L of air, for 6 hours per day).
NOEL
NOEL is no-observed-effect-level. It is the maximum dose of a substance that has no observable effect on the treated group in human clinical trials or animal experimental trials. In some literature, NOEL is the only dose level referred by the terminology ‘threshold dose’.
NOAEL
NOAEL is no-observed-adverse-effect-level. It is the maximum dose of a substance that has no observable adverse effect on the treated group in human clinical trials or animal experimental trials.
LOAEL
LOAEL is lowest-observed-adverse-effect-level. It is the minimum dose of a substance that produces an observable adverse effect on the treated group in human clinical trials or animal experimental trials. There is a biologically or statistically significant increase in the prevalence of adverse effect in the treated group above this level.
Establishment of dose levels
Factors affecting threshold dose
The dose-response relationship is dependent on various factors. They include the physicochemical properties of the drug, route of administration or exposure, duration of exposure, population size, and the characteristics of the studied organism such as their species, sex, ages, etc. The type of biological responses is also a significant factor for the variations of a dose-response relationship. Each response corresponds to one unique relationship. As it is not practical to establish the dose-response relationships for all possible responses, the studies usually narrow down the scopes to a few responses. All available studies examining the correlation between the target drug and its biological responses will be reviewed. The selection criteria for the critical responses for assessment is that the dose required to produce that particular response is the lowest. The precursor of a biological effect can also be the response for assessment. For instance, the risk factors of a disease may eventually precipitate the disease. In the study of the relationship between a drug and the development of a particular cardiovascular disease, the risk factors of the disease can be considered as the responses for measurement as well.
Process to evaluate threshold dose
A two-step process is adopted to evaluate the specific dose levels, NOAEL and LOAEL. The first step is to carry out reviews of available studies or animal studies to obtain data on the effect of different doses of the target drug. They allow the establishment of dose-response relationships over the range of doses reported in the data collected. Often the data collected is inadequate to produce a range wide enough to observe the dose in which biological responses are not induced in humans. The dose which is sufficiently low to prevent the occurrence of the response in humans cannot be evaluated and therefore paves the way to the second step, extrapolation of the dose-response relationship. The results beyond the range covered by the available data are estimated. It attempts to make inferences of the region that the critical dose levels such as NOAEL and LOAEL fell within. Thus the doses starting to trigger adverse effects in humans can be evaluated.
For step one, the two common approaches for evaluating threshold doses are qualitative examination of available studies and animal studies.
Qualitative examination of available studies
The effects of the target drug at different doses are obtained from available studies. The dose-response relationship will be identified and extrapolation is often required to make inferences about the dose levels below the range of data collected.
Animal Studies
Animal studies are conducted when the data collected from qualitative examination of available studies is scarce. It is for expanding the range of doses. Also, animal studies allow the manipulation of the study design, such as the age and gender of treated animals. Animal study is therefore less susceptible to the influences of confounders than observational studies and therefore contributes to a more rigorous dose-response assessment. As the assessed animals exhibit variation in characteristics with humans such as body size, extrapolation should be carried out to estimate the dose-response relationship in humans.
A common animal study is repeated dose toxicity testing. The participating species are divided into 4 groups, receiving placebo, low dose, mid-dose and high dose of the drugs respectively. Within the same group, the same dose is given on a daily basis for a specified period, such as 28 days or 90 days. Subsequent to the specified period, necropsy or tissue samples collection allows identification of the dose levels bring about certain effects and therefore establishment of NOAEL and LOAEL.
Significance
The threshold doses such as NOAEL, LOAEL and NOEL are essential values in risk assessment. The maximum safe starting doses of different drugs can be obtained from them prior to human clinical trials. Another application is to assess the safe dose for chronic exposure. They are utilized to estimate the daily exposure which does not induce detrimental effects in humans in their lifetime, which is also known as the Reference Dose (RfD).
The variations between different species and the extrapolation of dose-response relationship generated from animal studies to that for humans introduce uncertainties into the analysis of dose-response. Humans also manifest intra-variation of sensitivity towards a particular substance among the population. As a result, 10-fold uncertainty factors (UF) are applied to convert NOAEL to the reference dose. The UFinter and UFintra account for the inter- and intra-species variation respectively.
Limitations
Inapplicability
For carcinogenic substances, theoretically NOAEL and LOAEL do not exist as there is no safe dose for the carcinogens. A linear no-threshold model is commonly used for illustrating the probability of cancer development from radiation. There is no threshold value at which stochastic health effects start emerging. Only for non-cancer health outcomes, there is an assumption of the presence of a safety margin below which no negative biological effect is expected.
Inconsistency
Most dose-response models are obtained from animal experiments out of ethical concerns. Therefore, the results might not be consistent with that of the human population. Individual differences also arise among people in terms of age, weight, gender, health status, etc. Thus, in most circumstances, the threshold dose serves as a reference to evaluate the probable outcome of a certain dosage of a substance for the general population, while great deviations might exist in special populations such as immunocompromised patients, pregnant women and young children.
Incomprehensiveness
The threshold dose is only a measure of acute toxicity since the drug or toxic substance investigated is administered at once. The consequence of long-term administration remains unknown. As the threshold dose is the measured minimal response, its accuracy heavily depends on the machinery used. It is possible that further refinement is needed. Furthermore, the threshold dose only reflects the dose required for a minimum detectable response but it should not be misunderstood that health effects are absolutely absent in the doses below the threshold dose.
Other safety factors
LD50, LC50
The median lethal dose (LD50) of a substance is defined as the dose that leads to death in 50% of the tested population. It is a significant parameter in toxicology study and indicates the acute toxicity of a particular substance. LD50 is usually expressed in the weight of the chemical administered in milligram per unit of body weight (mg/kg). In the discussion of environmental toxins, as there is no direct administration of toxic materials, a similar parameter LC50 will be mentioned instead. LC50 is the concentration of substance in air that kills half of the tested population during the experimental period.
EC50
The median effective concentration (EC50) is the concentration of a drug required to reach 50% of the maximal biological effect the drug can exert. It is a reflection of the potency of a drug and is expressed in molar units such as mol/L. The value of EC50 greatly depends on the affinity of the drug for its receptor, as well as the efficacy of the drug, which conveys receptor occupancy and the ability of the drug to trigger a biological response. EC50 is incorporated in the Hill's Equation, a function that demonstrates the relationship between agonist concentration and ligand binding. EC50 is mathematically given as the inflection point of the equation.
References
Clinical pharmacology
Concentration indicators | Threshold dose | [
"Chemistry"
] | 2,077 | [
"Pharmacology",
"Clinical pharmacology"
] |
67,091,356 | https://en.wikipedia.org/wiki/Clostridium%20carnis | Clostridium carnis is a species of bacteria in the genus Clostridium.
References
carnis | Clostridium carnis | [
"Biology"
] | 24 | [
"Bacteria stubs",
"Bacteria"
] |
67,092,078 | https://en.wikipedia.org/wiki/Women%20in%20Data%20Science%20Initiative | In the field of AI and data science, companies lag in their ability to attract and retain talent, innovate, and meet shareholder/stakeholder expectations. As a significant portion of the population, the immense potential of women's talent is still excluded. Women in Data Science (WiDS) addresses the gender imbalance in data science/AI and works to remove barriers along the woman's journey – from her secondary school years to becoming a leader in her field. WiDS was sparked at Stanford University, California by Dr. Margot Gerritsen, Karen Matthys, and Dr. Esteban Arcaute, as the Women in Data Science (WiDS) Worldwide Initiative. Their mission is to achieve 30% representation for women in the field of data science by 2030, with a long-term vision of full and equal representation in decision-making, economic prosperity, and opportunities. WiDS's position on being able to create impact is with a strong network of universities, a global ambassador model, holistic programs addressing data science barriers, and nine years of experience with educational resources, this initiative provides scalable, culturally sensitive support and reaches over 150,000 women worldwide.
Impact
WiDS holds a Women in Data Science Worldwide conference annually, spotlighting only women speakers. These conferences are intended to inspire, educate, and sustain data science worldwide. In 2020, over 30,000 people participated, from 50 different countries. WiDs has reached over 100,000 women around the world. The Pune, India chapter of WiDS, for example, has over 5,000 members. Sucheta Dhere, ambassador of the WiDS Pune Chapter noted that computer vision, natural language processing, and machine learning "have a huge hiring potential in India," particularly for women. In 2019, more than 250 women convened in Madrid for the WIDS conference, which brought together women working on artificial intelligence and robotics. The Cambridge WiDS event was held at the Massachusetts Institute of Technology in 2020. Its signature event was a panel discussion on data science and fake news called “Data Weaponized, data Scrutinized: a war on information".
WiDS elevates women on the WiDS Platform through workshops, webinars, podcasts (on topics ranging from actionable ethics, automating machine learning, data analysis for health, and exploring artificial intelligence) and stories to raise visibility and inspire, while educating and lowering barriers to entry through programs like the Datathon and NextGen Data Days. Additionally, WiDS has global ambassadors which they empower by supporting and amplifying their efforts and providing opportunities for lifelong learning, career development, and progression, including through the WiDS UpLink job platform.
In 2024, WiDS has reached over 150,000 participants globally, including 5,000+ Datathon participants (75% women) from 100 countries, 2,300+ live workshop viewers, 1,000+ ambassadors across 77 countries, and 200 events worldwide, with 54% of ambassadors affiliated with universities or colleges.
Additionally, WiDS offers multiple ways to participate: Collaborators and sponsors support WiDS through active participation and funding of events, initiatives, and programs, while participants engage by attending conferences, workshops, and Datathons, and following WiDS across media platforms. Volunteers assist leadership and ambassadors in executing activities, while speakers, instructors, and podcast guests inspire by sharing knowledge. Ambassadors organize global events, advisors offer expert insights, and the central team leads in developing original content and resources for the community.
WiDS is also available to connect with across multiple social media platforms such as LinkedIn and Facebook Groups, Instagram, and their YouTube channel where they have a variety of content. WiDS also has a website that features blogs, events, monthly newsletters, and programs and resources they have to offer.
References
Stanford University
Facial recognition software
Diversity in computing | Women in Data Science Initiative | [
"Technology"
] | 786 | [
"Computing and society",
"Diversity in computing"
] |
67,093,003 | https://en.wikipedia.org/wiki/Andr%C3%A9%20Lichnerowicz%20Prize | The André Lichnerowicz Prize for Poisson geometry is a mathematics distinction awarded since 2008 to reward notable contributions to Poisson geometry.
Description of the prize
The prize is assigned once every two years during the International Conference on Poisson Geometry in Mathematics and Physics to one or two young researchers who obtained their doctorate in the eight years before the Conference.
It is awarded by a jury composed by members of the scientific and advisory committees of the conference, and its amount is financed by one of the hosting institutions or funding bodies.
The 2020 edition of the Poisson conference was postponed to 2021 and then cancelled due to the COVID-19 pandemic; accordingly, the André Lichnerowicz Prize for 2020 was assigned online on May 27, 2021, in occasion of the Global Poisson Webinar.
The prize is named in memory of André Lichnerowicz (1915-1998), whose works have been fundamental in establishing Poisson geometry as a branch of modern mathematics.
Laureates
2024: Ana Balibanu and Francis Bischoff
2022: Yiannis Loizides and Álvaro del Pino Gómez
2020: Pavel Safronov and Xiaomeng Xu
2018: Brent Pym and Chelsea Walton
2016: Pavel Mnev and Travis Schedler
2014: David Li-Bland and Ioan Mărcuţ
2012: Thomas Willwacher
2010: Marco Gualtieri and Xiang Tang
2008: Marius Crainic and Henrique Bursztyn.
References
Mathematics awards | André Lichnerowicz Prize | [
"Technology"
] | 300 | [
"Science and technology awards",
"Mathematics awards"
] |
67,093,097 | https://en.wikipedia.org/wiki/Gas%20chromatography-olfactometry | Gas chromatography-olfactometry (GC-O) is a technique that integrates the separation of volatile compounds using a gas chromatograph with the detection of odour using an olfactometer (human assessor). It was first invented and applied in 1964 by Fuller and co-workers. While GC separates volatile compounds from an extract, human olfaction detects the odour activity of each eluting compound. In this olfactometric detection, a human assessor may qualitatively determine whether a compound has odour activity or describe the odour perceived, or quantitatively evaluate the intensity of the odour or the duration of the odour activity. The olfactometric detection of compounds allows the assessment of the relationship between a quantified substance and the human perception of its odour, without instrumental detection limits present in other kinds of detectors. Compound identification still requires use of other detectors, such as mass spectrometry, with analytical standards.
Olfactory perception
The properties of a compound relating to human olfactory perception includes its odour quality, threshold and intensity as a function of its concentration.
The odour quality of a (odour-active) compound is assessed using odour descriptors in sensory descriptive analyses. It shows the sensory–chemical relationship in volatile compounds. The odour quality of a compound may change with its concentration.
The absolute threshold of a compound is the minimum concentration at which it can be detected. In a mixture of volatile compounds, only the proportion of compounds present at concentrations above their threshold contribute to the odour. This property can be represented by the odour threshold (OT), the minimum concentration at which the odour is perceived by 50% of a human panel without determining its quality, or the recognition threshold, the minimum concentration at which the odour is perceived and can be described by 50% of a human panel.
The intensity of perception of a compound is positively correlated with its concentration. It is represented by the unique psychometric or concentration-response function of the compound. A psychometric function with a log concentration–perceived intensity plot is characterised by its sigmoidal shape, with its initial baseline representing the compound at concentrations below its threshold, a slow rise in response around the inflection point representing the threshold, an exponential rise in response as the concentration exceeds the threshold, a deceleration of the response to a flat region as the zone of saturation or the point at which the change in intensity is no longer perceived is reached. On the other hand, a log concentration–log perceived intensity plot, using Steven's power law, forms a linear line with the exponent characterising the relationship between the two variables.
Experimental design
The apparatus consists of a gas chromatograph equipped with an odour port (ODP), in place of or in addition to conventional detectors, from with human assessors sniff the eluates. The odour port is characterised by its nose-cone design connected to the GC instrument by a transfer line. The odour port is commonly glass or polytetrafluoroethylene. It is generally placed 30–60 cm away from the instrument, extending from the side such that it is not affected by the hot GC oven. The deactivated silica transfer line is generally heated to prevent the condensation of less-volatile compounds. It is flexible so that the assessor can adjust it according to their comfortable sitting position. As traditional warm and dry carrier gases may dehydrate the mucous membrane of the nose, volatiles are delivered via auxiliary gas or humidified carrier gas, with relative humidity (RH) of 50–75%, to ease the dehydration.
The olfactometric detector may be coupled with, or connected in parallel to, a flame ionization detector (FID) or mass spectrometer (MS). Moreover, multiple odour ports may be set-up. In these cases, the eluate is generally split evenly between the detectors to allow it to reach the detectors simultaneously.
Methods of detection
In a GC-O analysis, various methods are used to determine the odour contribution of a compound or the relative importance of each odorant. The methods can be categorised as (i) detection frequency, (ii) dilution to threshold and (iii) direct intensity.
Detection frequency
The GC-O analysis is carried out by a panel of 6–12 assessors to count the number of participants who perceive an odour at each retention time. This frequency is then used to represent the relative importance of an odorant in the extract. It is also presumed to relate to the intensity of the odorant at the particular concentration, based on the assumption that individual detection thresholds are normally distributed.
Two different kinds of data can be reported by this method depending on the data collected. First, if only frequency data is available, it is reported as the nasal impact frequency (NIF) or the peak height of the olfactometric signal. It is zero if no assessor senses the odour and added with one each time an assessor senses an odour. Second, if both frequency of detection and duration of odour are collected, the surface of NIF (SNIF) or the peak area corresponding to the product of frequency of detection (%) and duration of odour (s) can be interpreted. SNIF allows further interpretation of odour compounds other than just peak height.
The detection frequency method benefits from its simplicity and lack of requirement for trained assessors, as the signal recorded is binary (presence/absence of odour). On the other hand, a drawback of this method is the limitation to the assumption of the relationship between frequency and perceived odour intensity. Odour-active compounds in food samples are often present at concentrations above their detection thresholds. This means that a compound may be detected by all assessors and therefore reach the limit of 100% detection in spite of increases in intensity.
Dilution to threshold
A dilution series of a sample or extract is prepared and assessed for presence of odour. The result can be described as the odour potency of a compound.
One kind of analysis is to measure the maximum dilution in the series in which odour is still perceived. The resulting value is called the flavour dilution (FD) factor in the aroma extraction dilution analysis (AEDA) developed in 1987 by Schieberle and Grosch. On the other hand, another kind of analysis is to also measure the duration of the perceived odour to compute peak areas. The peak areas are known as Charm values in the CharmAnalysis developed in 1984 by Acree and co-workers. The former can then be interpreted as the peak height of the latter. Because the odour threshold of a compound is intended to be measured from a prepared series of dilution (commonly by a factor of 2–3 with 8–10 dilutions), the precision and variation in data can be determined from the dilution factors used.
Due to time demand requirements from this method and the general requirement for multiple assessors to minimise errors, having the column split into multiple odour ports would be beneficial for the method.
Direct intensity
This method adds to the dilution to threshold method by considering the perceived intensity of the compounds as well. Assessors can report this based on a predetermined scale.
The posterior intensity method measures the maximum intensity perceived for each eluting compound. A panel of assessors is recommended to be used to obtain an averaged signal. On the other hand, the dynamic time-intensity method measures
the intensity at different points in time starting from the time of elution, allowing a continuous measurement of onset, maximum, and decline of the odour intensity. This is used in the Osme (Greek word for odour) method developed in 1992 by Da Silva. An aromagram can then be constructed in a similar way as an FID chromatogram whereby intensity is plotted as a function of retention time. The peak height corresponds to the maximum intensity perceived whereas the peak width corresponds to the duration of the odour perceived.
The time requirement maybe high for this particular method regarding the essentials of assessor training, as lack of training may result in inconsistencies in scale usage. However, with a trained panel of assessors, the analysis can be done in a relatively short amount of time with high precision.
Variations
Gas chromatography/mass spectrometry-olfactometry (GC/MS-O)
GC-recomposition-olfactometry (GC-R)
Multi-gas chromatography-olfactometry
References
External links
Gas Chromatography–Olfactometry: Principles, Practical Aspects and Applications in Food Analysis
Analytical chemistry
Laboratory techniques | Gas chromatography-olfactometry | [
"Chemistry"
] | 1,853 | [
"Chromatography",
"Gas chromatography"
] |
67,093,341 | https://en.wikipedia.org/wiki/CD-73%C2%B0375 | CD-73°375 is a binary star located in the constellation Volans about away. The two components, HR 2979 and HR 2980, are separated by two arc-seconds. The pair has a combined apparent magnitude of 6.34. It has a radial velocity of about , which means it drifting away from the Solar System.
Properties
The two stars making up CD-73°375 are both B9 subgiants with almost identical properties. HR 2979 is generally designated as the primary because of its higher mass, although HR 2980 is marginally brighter at magnitude 7.02. They are apart and have an assumed orbit of 3,760 years.
Each star has a mass about three and a half times the Sun's and a temperature of about .
References
Volans
B-type subgiants
Binary stars
2979 80
62153 4
036914
Durchmusterung objects | CD-73°375 | [
"Astronomy"
] | 187 | [
"Volans",
"Constellations"
] |
41,329,158 | https://en.wikipedia.org/wiki/CBR96-doxorubicin%20immunoconjugate | cBR96-doxorubicin immunoconjugate (BMS-182248/SGN-15; also known as cBR96-Dox) is an antibody-drug conjugate or (ADC) directed to the Lewis-Y antigen designed for the treatment of cancer. The payload is the chemotherapy drug doxorubicin which is connected with a hydrazone linker to cysteine residues of the Lewis-Y specific (chimeric) monoclonal antibody BR96. Following internalization, the hydrazone is hydrolyzed within the acidic environment of target cell endosomes and lysosomes to release active cytotoxic drug.
Clinical Development
In clinical trials cBR96-Dox was found to be highly active in regressing large human tumor xenografts implanted in mice or rats. Multiple tumor models including lung, breast and colon were evaluated, and cBR96-Dox was found to have broad and potent anti-tumor activity, even in doxorubicin-resistant tumors.
References
Monoclonal antibodies
Unnamed monoclonal antibodies
Antibody-drug conjugates | CBR96-doxorubicin immunoconjugate | [
"Biology"
] | 247 | [
"Antibody-drug conjugates"
] |
41,330,159 | https://en.wikipedia.org/wiki/WR%20134 | WR 134 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus, surrounded by a faint bubble nebula blown by the intense radiation and fast wind from the star. It is five times the radius of the sun, but due to a temperature over it is 400,000 times as luminous as the Sun.
WR 134 was one of three stars in Cygnus observed in 1867 to have unusual spectra consisting of intense emission lines rather than the more normal continuum and absorption lines. These were the first members of the class of stars that came to be called Wolf-Rayet stars (WR stars) after Charles Wolf and Georges Rayet who discovered their unusual appearance. It is a member of the nitrogen sequence of WR stars, while the other two (WR 135 and WR 137) are both members of the carbon sequence that also have OB companions. WR 134 has a spectrum with NIII and NIV emission between two and five times stronger than NV, leading to the assignment of a WN6 spectral type. The spectrum also shows strong HeII emission and weaker lines of HeI and CIV.
WR 134 is classified as an Algol type eclipsing variable and given the designation V1769 Cygni, but the variation is not strictly periodic and brightness changes occur on timescales of hours to days. It has been investigated several times to search for companions. Morel reported a 2.25 day primary period but considered the variations to be due to rotational modulation rather than the effects of a companion. Rustamov suggests a 1.887 day orbital period with a K-M dwarf companion, but with additional optical variations.
Both hard and soft X-rays have been detected from WR 134 but the sources are not fully explained. The emissions do not match a single star of the expected temperature, are not sufficient for colliding winds between two hot stars, and any compact source such as a neutron star or cool dwarf would be in an unlikely orbit.
WR 134 is less than a degree away from WR 135 and the two are believed to lie at approximately the same distance from Earth within the Cygnus OB3 association. Both stars lie within a shell of hydrogen thought to have been swept up from the interstellar medium when one or both stars were on the main sequence. The shell is over forty parsecs wide and contains about of hydrogen. It is unclear which of the two stars is primarily responsible for creating the shell.
References
External links
Wolf Rayet shells
NOAO page
WR134 and WR135
Cygnus (constellation)
Wolf–Rayet stars
Cygni, V1769
Durchmusterung objects
191765
Algol variables
099377 | WR 134 | [
"Astronomy"
] | 554 | [
"Cygnus (constellation)",
"Constellations"
] |
41,330,767 | https://en.wikipedia.org/wiki/Accelerationism | Accelerationism is a range of revolutionary and reactionary ideas in left-wing and right-wing ideologies that call for the drastic intensification of capitalist growth, technological change, infrastructure sabotage and other processes of social change to destabilize existing systems and create radical social transformations, otherwise referred to as "acceleration". It has been regarded as an ideological spectrum divided into mutually contradictory left-wing and right-wing variants, both of which support the indefinite intensification of capitalism and its structures as well as the conditions for a technological singularity, a hypothetical point in time at which technological growth becomes uncontrollable and irreversible.
Various ideas, including Gilles Deleuze and Félix Guattari's idea of deterritorialization, Jean Baudrillard's proposals for "fatal strategies", and aspects of the theoretical systems and processes developed by English philosopher and later Dark Enlightenment commentator Nick Land, are crucial influences on accelerationism, which aims to analyze and subsequently promote the social, economic, cultural, and libidinal forces that constitute the process of acceleration. While originally used by the far-left, the term has, in a manner strongly distinguished from original accelerationist theorists, been used by right-wing extremists such as neo-fascists, neo-Nazis, white nationalists and white supremacists to increasingly refer to an "acceleration" of racial conflict through assassinations, murders and terrorist attacks as a means to violently achieve a white ethnostate.
While predominantly a political strategy suited to the industrial economy, acceleration has recently been discussed in debates about humanism and artificial intelligence. Yuk Hui and Louis Morelle consider acceleration and the "singularity hypothesis". James Brusseau discusses acceleration as an ethics of innovation where humanistic dilemmas caused by artificial intelligence (AI) innovation are resolved by still more innovation, as opposed to limiting or slowing the technology. A movement known as effective accelerationism (abbreviated to e/acc) advocates for technological progress "at all costs".
Background and precursors
The term "accelerationism" was first used as a critique of techno-optimism in Robert Musil's 1930 book The Man Without Qualities. It also appears in sci-fi author Roger Zelazny's third novel, 1967's Lord of Light.
The term was popularized by professor and author Benjamin Noys in his 2010 book The Persistence of the Negative to describe the trajectory of certain post-structuralists who embraced unorthodox Marxist and counter-Marxist overviews of capitalist growth, such as Gilles Deleuze and Félix Guattari in their 1972 book, Anti-Oedipus, Jean-François Lyotard in his 1974 book Libidinal Economy and Jean Baudrillard in his 1976 book Symbolic Exchange and Death.
English right-wing philosopher and writer Nick Land, commonly credited with creating and inspiring accelerationism's basic ideas and concepts, cited a number of philosophers who express anticipatory accelerationist attitudes in his 2017 essay "A Quick-and-Dirty Introduction to Accelerationism". Firstly, Friedrich Nietzsche argued in a fragment in The Will to Power that "the leveling process of European man is the great process which should not be checked: one should even accelerate it." Then, taking inspiration from this notion for Anti-Oedipus, Deleuze and Guattari speculated on an unprecedented "revolutionary path" to further perpetuate capitalism's tendencies that would later become a central idea of accelerationism:
Land also cited Karl Marx, who, in his 1848 speech "On the Question of Free Trade", anticipated accelerationist principles a century before Deleuze and Guattari by describing free trade as socially destructive and fuelling class conflict, then effectively arguing for it:
Land attributed the increasing speed of the modern world, along with the associated decrease in time available to think and make decisions about its events, to unregulated capitalism and its ability to exponentially grow and self-improve, describing capitalism as "a positive feedback circuit, within which commercialization and industrialization mutually excite each other in a runaway process." He argued that the best way to deal with capitalism is to participate more to foster even greater exponential growth and self-improvement via creative destruction, believing such acceleration of those abilities and technological progress to be intrinsic to capitalism but impossible for non-capitalist systems, stating that "capital revolutionizes itself more thoroughly than any extrinsic 'revolution' possibly could."
Contemporary accelerationism
The Cybernetic Culture Research Unit (CCRU), an experimental theory collective that existed from 1995 to 2003 at the University of Warwick, included Land as well as other influential social theorists such as Mark Fisher and Sadie Plant as members. Prominent contemporary left-wing accelerationists include Nick Srnicek and Alex Williams, authors of the "Manifesto for an Accelerationist Politics"; and the Laboria Cuboniks collective, who authored the manifesto "Xenofeminism: A Politics for Alienation". For Mark Fisher, writing in 2012, "Land's withering assaults on the academic left [...] remain trenchant", although problematic since "Marxism is nothing if it is not accelerationist". Aria Dean notably synthesized the analysis of racial capitalism with accelerationism, arguing that the binary between humans, and machines and capital, is already blurred by the scars of the Atlantic slave trade. Benjamin H. Bratton's book The Stack: On Software and Sovereignty has been described as concerning accelerationist ideas, focusing on how information technology infrastructures undermine modern political geographies and proposing an open-ended "design brief". Tiziana Terranova's "Red Stack Attack!" links Bratton's stack model and left-wing accelerationism.
Left-wing accelerationism
Left-wing accelerationism, commonly referred to as "L/Acc", is often attributed to Mark Fisher, a prior CCRU member and mentor for Srnicek and Williams. Left-wing accelerationism seeks to explore, in an orthodox and conventional manner, how modern society has the momentum to create futures that are equitable and liberatory. While both strands of accelerationist thinking remain rooted in a similar range of thinkers, left accelerationism appeared with the intent to use their ideas for the goal of achieving an egalitarian future. In response to this strand of accelerationism and its optimism for egalitarianism and liberation, which departs from prior interests in experimentation and delirium, Land rebuked its ideas in an interview with The Guardian, saying that "the notion that self-propelling technology is separable from capitalism is a deep theoretical error".
Other uses of the term
Since "accelerationism" was coined in 2010, the term has taken on several new meanings, particularly by right-wing extremist movements and terrorist organizations, that has led the term to be sensationalized on multiple occasions. Several commentators have used the label accelerationist to describe a controversial political strategy articulated by the Slovenian philosopher, Freudo-Marxist theorist, and writer Slavoj Žižek. An often-cited example of this is Žižek's assertion in a November 2016 interview with Channel 4 News that were he an American citizen, he would vote for former U.S. president Donald Trump as the candidate more likely to disrupt the political status quo in that country.
Far-right accelerationist terrorism
Despite its originally Marxist philosophical and theoretical interests, since the late 2010s, international networks of neo-fascists, neo-Nazis, White nationalists, and White supremacists have increasingly used the term "accelerationism" to refer to right-wing extremist goals, and have been known to refer to an "acceleration" of racial conflict through violent means such as assassinations, murders, terrorist attacks and eventual societal collapse, to achieve the building of a White ethnostate. Far-right accelerationism has been widely considered as detrimental to public safety. The inspiration for this distinct variation is occasionally cited as American Nazi Party and National Socialist Liberation Front member James Mason's newsletter Siege, where he argued for sabotage, mass killings, and assassinations of high-profile targets to destabilize and destroy the current society, seen as a system upholding a Jewish and multicultural New World Order. His works were republished and popularized by the Iron March forum and Atomwaffen Division, right-wing extremist organizations strongly connected to various terrorist attacks, murders, and assaults. According to the Southern Poverty Law Center (SPLC), which tracks hate groups and files class action lawsuits against discriminatory organizations and entities, "on the case of white supremacists, the accelerationist set sees modern society as irredeemable and believe it should be pushed to collapse so a fascist society built on ethnonationalism can take its place. What defines white supremacist accelerationists is their belief that violence is the only way to pursue their political goals."
Brenton Harrison Tarrant, the perpetrator of the 15 March 2019 Christchurch mosque shootings that killed 51 people and injured 49 others, strongly encouraged right-wing accelerationism in a section of his manifesto titled "Destabilization and Accelerationism: Tactics". Tarrant's manifesto influenced John Timothy Earnest, the perpetrator of both the 24 March 2019 Escondido mosque fire at Dar-ul-Arqam Mosque in Escondido, California, and the 27 April 2019 Poway synagogue shooting which resulted in one dead and three injured; and it also influenced Patrick Crusius, the perpetrator of the 3 August 2019 El Paso Walmart shooting that killed 23 people and injured 23 others. Tarrant and Earnest, in turn, influenced Juraj Krajčík, the perpetrator of the 2022 Bratislava shooting that left dead two patrons of a gay bar. Sich Battalion urged its members to buy a copy of Tarrant's manifesto, encouraging them to "get inspired" by it.
Although these right-wing extremist variants and their connected strings of terrorist attacks and murders are regarded as certainly uninformed by critical theory, which was a prime source of inspiration for Land's original ideas that led to accelerationism, Land himself became interested in the Atomwaffen-affiliated theistic Satanist organization Order of Nine Angles (ONA), that adheres to the ideology of Neo-Nazi terrorist accelerationism, describing the ONA's works as "highly-recommended" in a blog post. Since the 2010s, the political ideology and religious worldview of the Order of Nine Angles, founded by the British neo-Nazi leader David Myatt in 1974, have increasingly influenced militant neo-fascist and neo-Nazi insurgent groups associated with right-wing extremist and White supremacist international networks, most notably the Iron March forum.
Fascist accelerationist organizations
Active Club Network is decentralized Clandestine cell system of white nationalists. It promotes mixed martial arts to fight against what it asserts is a system that is targeting the white race, as well as a "warrior spirit" to prepare for a forthcoming race war. Some extremism researchers have characterized the network as a "shadow or stand-by army" which is awaiting activation as the need for it arises.
Atomwaffen Division is a neo-Nazi terror organization found in 2013 by Brandon Russell responsible for multiple murders and mass casualty plots. Atomwaffen has been proscribed as a terror organization in United Kingdom, Canada and Australia.
The Base is a neo-Nazi, white supremacist paramilitary hate group and training network, formed in 2018 by Rinaldo Nazzaro and active in the United States, Canada, Australia, South Africa, and Europe. it is considered a terrorist organization in Canada, Australia, New Zealand, and the United Kingdom.
Combat 18 is a neo-Nazi organization that has been proscribed in Canada and Germany and is tied to the assassination of Walter Lübcke and the 2009 Vítkov arson attack.
The Manson Family was a doomsday cult, led by Charles Manson, responsible for the Tate–LaBianca murders, in which seven people were murdered between August 8 and August 10, 1969. Manson was a white supremacist and neo-Nazi who prophesized about a race war in which African-Americans would rise up and exterminate all white people in the United States, with him and his followers hiding in safety. Afterward, the Family would rule over the Black population, with Manson as their "master," as he believed that Black people were not intelligent enough to govern themselves. The Tate–LaBianca murders were an attempt to bring this scenario closer to reality, with Manson believing that the killing of people who he considered "pigs" would inspire Black people to do the same.
Nordic Resistance Movement is a pan-Nordic neo-Nazi organization that adheres to accelerationism and is tied to ONA and multiple terror plots and murders, like the murder of an antifascist in Helsinki in 2016. There has been an international effort to proscribe NRM as a terrorist organization, and it was banned as such in Finland in 2019. On 14 June 2024, the United States Department of State designated NRM and its leaders as Specially Designated Global Terrorists (SDGT).
Order of Nine Angles is a neo-Nazi satanist organization that has been connected to multiple murders and terror plots. There has been an international effort to proscribe ONA as a terror organization. Further, the ONA is connected to the Atomwaffen and the Base, and the founder of ONA David Myatt was a one-time leader of the C18.
Russian Imperial Movement is a white supremacist organization founded in Russia and proscribed as a terror organization in the United States and Canada for its connection to neo-fascist terrorists. People trained by RIM have gone on to commit a series of bombings and joined the separatist militants in Donbas.
See also
Christian Identity#Revolutionary violence
Ecofascism#Association with violence
References
2010s neologisms
Anti-capitalism
Anti-fascism
Critical theory
Far-left politics
Right-wing terrorism
Ideologies of capitalism
Marxism
Neo-Nazism
Reactionary
Revolution terminology
Singularitarianism
Social theories
Social change
Transhumanism
Philosophy of technology | Accelerationism | [
"Technology",
"Engineering",
"Biology"
] | 2,910 | [
"Existential risk from artificial general intelligence",
"Philosophy of technology",
"Science and technology studies",
"Genetic engineering",
"Transhumanism",
"Ethics of science and technology"
] |
41,331,583 | https://en.wikipedia.org/wiki/Erbium%20tetraboride | Erbium tetraboride is a boride of the lanthanide metal erbium.
It is hard and has a high melting point. Industrial applications of erbium boride include use in semiconductors, the blades of gas turbines, and the nozzles of rocket engines.
References
Borides
Erbium compounds | Erbium tetraboride | [
"Chemistry"
] | 70 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
41,331,720 | https://en.wikipedia.org/wiki/Weyr%20canonical%20form | In mathematics, in linear algebra, a Weyr canonical form (or, Weyr form or Weyr matrix) is a square matrix which (in some sense) induces "nice" properties with matrices it commutes with. It also has a particularly simple structure and the conditions for possessing a Weyr form are fairly weak, making it a suitable tool for studying classes of commuting matrices. A square matrix is said to be in the Weyr canonical form if the matrix has the structure defining the Weyr canonical form. The Weyr form was discovered by the Czech mathematician Eduard Weyr in 1885. The Weyr form did not become popular among mathematicians and it was overshadowed by the closely related, but distinct, canonical form known by the name Jordan canonical form. The Weyr form has been rediscovered several times since Weyr’s original discovery in 1885. This form has been variously called as modified Jordan form, reordered Jordan form, second Jordan form, and H-form. The current terminology is credited to Shapiro who introduced it in a paper published in the American Mathematical Monthly in 1999.
Recently several applications have been found for the Weyr matrix. Of particular interest is an application of the Weyr matrix in the study of phylogenetic invariants in biomathematics.
Definitions
Basic Weyr matrix
Definition
A basic Weyr matrix with eigenvalue is an matrix of the following form: There is an integer partition
of with
such that, when is viewed as an block matrix , where the block is an matrix, the following three features are present:
The main diagonal blocks are the scalar matrices for .
The first superdiagonal blocks are full column rank matrices in reduced row-echelon form (that is, an identity matrix followed by zero rows) for .
All other blocks of W are zero (that is, when ).
In this case, we say that has Weyr structure .
Example
The following is an example of a basic Weyr matrix.
In this matrix, and . So has the Weyr structure . Also,
and
General Weyr matrix
Definition
Let be a square matrix and let be the distinct eigenvalues of . We say that is in Weyr form (or is a Weyr matrix) if has the following form:
where is a basic Weyr matrix with eigenvalue for .
Example
The following image shows an example of a general Weyr matrix consisting of three basic Weyr matrix blocks. The basic Weyr matrix in the top-left corner has the structure (4,2,1) with eigenvalue 4, the middle block has structure (2,2,1,1) with eigenvalue -3 and the one in the lower-right corner has the structure (3, 2) with eigenvalue 0.
Relation between Weyr and Jordan forms
The Weyr canonical form is related to the Jordan form by a simple permutation for each Weyr basic block as follows: The first index of each Weyr subblock forms the largest Jordan chain. After crossing out these rows and columns, the first index of each new subblock forms the second largest Jordan chain, and so forth.
The Weyr form is canonical
That the Weyr form is a canonical form of a matrix is a consequence of the following result: Each square matrix over an algebraically closed field is similar to a Weyr matrix which is unique up to permutation of its basic blocks. The matrix is called the Weyr (canonical) form of .
Computation of the Weyr canonical form
Reduction to the nilpotent case
Let be a square matrix of order over an algebraically closed field and let the distinct eigenvalues of be . The Jordan–Chevalley decomposition theorem states that is similar to a block diagonal matrix of the form
where is a diagonal matrix, is a nilpotent matrix, and , justifying the reduction of into subblocks . So the problem of reducing to the Weyr form reduces to the problem of reducing the nilpotent matrices to the Weyr form. This is leads to the generalized eigenspace decomposition theorem.
Reduction of a nilpotent matrix to the Weyr form
Given a nilpotent square matrix of order over an algebraically closed field , the following algorithm produces an invertible matrix and a Weyr matrix such that .
Step 1
Let
Step 2
Compute a basis for the null space of .
Extend the basis for the null space of to a basis for the -dimensional vector space .
Form the matrix consisting of these basis vectors.
Compute . is a square matrix of size − nullity .
Step 3
If is nonzero, repeat Step 2 on .
Compute a basis for the null space of .
Extend the basis for the null space of to a basis for the vector space having dimension − nullity .
Form the matrix consisting of these basis vectors.
Compute . is a square matrix of size − nullity − nullity.
Step 4
Continue the processes of Steps 1 and 2 to obtain increasingly smaller square matrices and associated invertible matrices until the first zero matrix is obtained.
Step 5
The Weyr structure of is where = nullity.
Step 6
Compute the matrix (here the 's are appropriately sized identity matrices).
Compute . is a matrix of the following form:
.
Step 7
Use elementary row operations to find an invertible matrix of appropriate size such that the product is a matrix of the form .
Step 8
Set diag and compute . In this matrix, the -block is .
Step 9
Find a matrix formed as a product of elementary matrices such that is a matrix in which all the blocks above the block contain only 's.
Step 10
Repeat Steps 8 and 9 on column converting -block to via conjugation by some invertible matrix . Use this block to clear out the blocks above, via conjugation by a product of elementary matrices.
Step 11
Repeat these processes on columns, using conjugations by . The resulting matrix is now in Weyr form.
Step 12
Let . Then .
Applications of the Weyr form
Some well-known applications of the Weyr form are listed below:
The Weyr form can be used to simplify the proof of Gerstenhaber’s Theorem which asserts that the subalgebra generated by two commuting matrices has dimension at most .
A set of finite matrices is said to be approximately simultaneously diagonalizable if they can be perturbed to simultaneously diagonalizable matrices. The Weyr form is used to prove approximate simultaneous diagonalizability of various classes of matrices. The approximate simultaneous diagonalizability property has applications in the study of phylogenetic invariants in biomathematics.
The Weyr form can be used to simplify the proofs of the irreducibility of the variety of all k-tuples of commuting complex matrices.
References
Linear algebra
Matrix theory
Matrix normal forms
Matrix decompositions | Weyr canonical form | [
"Mathematics"
] | 1,398 | [
"Linear algebra",
"Algebra"
] |
41,331,733 | https://en.wikipedia.org/wiki/Girth%20%28geometry%29 | In three-dimensional geometry, the girth of a geometric object, in a certain direction, is the perimeter of its parallel projection in that direction. For instance, the girth of a unit cube in a direction parallel to one of the three coordinate axes is four: it projects to a unit square, which has four as its perimeter.
Surfaces of constant girth
The girth of a sphere in any direction equals the circumference of its equator, or of any of its great circles. More generally,
if is a surface of constant width , then every projection of is a curve of constant width, with the same width . All curves of constant width have the same perimeter, the same value as the circumference of a circle with that width (this is Barbier's theorem). Therefore, every surface of constant width is also a surface of constant girth: its girth in all directions is the same number . Hermann Minkowski proved, conversely, that every convex surface of constant girth is also a surface of constant width.
Projection versus cross-section
For a prism or cylinder, its projection in the direction parallel to its axis is the same as its cross section, so in these cases the girth also equals the perimeter of the cross section. In some application areas such as shipbuilding this alternative meaning, the perimeter of a cross section, is taken as the definition of girth.
Application
Girth is sometimes used by postal services and delivery companies as a basis for pricing. For example, Canada Post requires that an item's length plus girth not exceed a maximum allowed value. For a rectangular box, the girth is 2 * (height + width), i.e. the perimeter of a projection or cross section perpendicular to its length.
References
Euclidean solid geometry | Girth (geometry) | [
"Physics"
] | 363 | [
"Spacetime",
"Space",
"Euclidean solid geometry"
] |
41,331,931 | https://en.wikipedia.org/wiki/Vadastuximab%20talirine | Vadastuximab talirine is an antibody-drug conjugate (ADC) directed to CD33 (siglec-3) which is a transmembrane receptor expressed on cells of myeloid lineage. The experimental drug, being developed by Seattle Genetics, was in clinical trials for the treatment of acute myeloid leukemia (AML).
Development of vadastuximab talirine was discontinued in 2017 after a pivotal phase III clinical trial.
Target, mAb, linker, and cytotoxin
The drug target, CD33, is expressed on most AML cells. The CD33 antibody is attached to a highly potent DNA binding agent, a pyrrolobenzodiazepine (PBD) dimer (SGD-1882), via a proprietary site-specific conjugation chemistry via a cleavable (valine-alanine dipeptide as cathepsin B cleavage site) maleimidocaproyl type linker, to a monoclonal antibody with engineered cysteines (EC-mAb). Vadastuximab talirine contains two site-specific drug attachment engineered cysteines. This use of engineered cysteine residues at the sites of drug linker attachment results in a drug loading of approximately 2 PBD dimers per antibody. PBD dimers are significantly more potent than systemic chemotherapeutic drugs and the site-specific conjugation technology (EC-mAb) allows uniform drug-loading of the cell-killing PBD agent to the anti-CD33 antibody.
Clinical trials
The drug has concluded phase I clinical trials for acute myeloid leukemia. Interim results were presented in Dec 2014. and published April 2015.
Based on interim data from ongoing phase I clinical trials presented at the 57th Annual Meeting of the American Society of Hematology (ASH), researchers at Seattle Genetics have planned a phase III clinical trial to begin in 2016. This phase III study is expected to evaluate vadastuximab talirine in combination with hypomethylating agents (HMAs; azacitidine, decitabine) in previously untreated older AML patients. The drug is also being evaluated broadly across multiple lines of therapy in patients with myeloid malignancies, including in ongoing and planned phase I and II clinical trials for newly diagnosed or relapsed AML and for newly diagnosed myelodysplastic syndrome or MDS.
A phase III clinical trial of Vadastuximab talirine in combination with hypomethylating agents, was terminated, however, in June 2017 due to a higher rate of deaths resulting from fatal infections.
Orphan drug designation
Vadastuximab talirine was granted orphan drug designation by both the U.S. Food and Drug Administration (FDA) and the European Commission for the treatment of AML.
References
Antibody-drug conjugates
Monoclonal antibodies
Pyrrolobenzodiazepines | Vadastuximab talirine | [
"Biology"
] | 621 | [
"Antibody-drug conjugates"
] |
41,332,572 | https://en.wikipedia.org/wiki/Erbium%28III%29%20iodide | Erbium(III) iodide is an iodide of lanthanide metal erbium. The compound is insoluble in water and is white to slightly pink in appearance.
Preparation
Erbium(III) iodide can be produced by the reaction of elemental iodine and finely divided erbium by the following equation:
Properties
Erbium(III) iodide has a trigonal crystal structure with space group R (space group no. 148).
References
Erbium compounds
Iodides
Lanthanide halides | Erbium(III) iodide | [
"Chemistry"
] | 115 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
41,332,848 | https://en.wikipedia.org/wiki/N-Vinylacetamide | N-Vinylacetamide (NVA) is a non-ionic monomer. Copolymers made of NVA and other monomers can exhibit practical characteristics in addition to those common with the existing hydrophilic polymers.
History
NVA is an amphipathic monomer. It was introduced and compounded in the U.S. in 1967. Today, it is recognized as a monomer that does polymerize; however, Showa Denko K.K. succeeded in its industrialization in 1997.
Properties
NVA is soluble in water, various organic solvents and liquid vinyl monomers. It is polymerizable by various radical polymerization processes, depending on the objective. Since NVA itself is a solvent, it can act as a dissolution agent for poorly soluble substances.
References
Acetamides
Amide solvents
Plasticizers
Monomers
Vinyl compounds | N-Vinylacetamide | [
"Chemistry",
"Materials_science"
] | 177 | [
"Monomers",
"Polymer chemistry"
] |
41,332,950 | https://en.wikipedia.org/wiki/Barium%20hexaboride | Barium hexaboride is a hard material with a high melting point. It can be formed by passing a barium vapour at >750 °C over boron crystals:
However, it can also be formed by reacting barium chloride with boron in two stages: firstly at 900 °C for 30 minutes and then at 1,500 °C for 60 minutes.
Potential applications
Barium hexaboride has been considered as a candidate for use in hot-cathode electron guns.
References
Barium compounds
Borides | Barium hexaboride | [
"Chemistry"
] | 107 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
41,333,269 | https://en.wikipedia.org/wiki/Robin%20Ferrier | Robert John Ferrier FRSNZ, FNZIC, (7 August 1932 – 11 July 2013) was an organic chemist who discovered two chemical reactions, the Ferrier rearrangement and the Ferrier carbocyclization. Originally from Edinburgh, he moved to Wellington, New Zealand, in 1970.
Early life and education
Ferrier was born in Edinburgh on 7 August 1932. Following the family's idiosyncratic naming tradition, although he was named Robert John, he was always known as Robin. Likewise his father Edward was known as William and his mother Sophia was known as Rita. William was a policeman and became head of Edinburgh CID, while Rita was a housewife.
His only sibling was a fraternal twin sister Dr Barbara M. Ferrier (d. 2006), known as Ray, who likewise became an organic chemist, becoming professor emeritus of the Department of Biochemistry and Biomedical Sciences at McMaster University. A polycyclic ketone "barbaralone", related to bullvalene was named after her.
Ferrier attended George Heriot's School for all of his schooling, apart from a brief time in Traquair, to where he was evacuated during the war with his mother and sister.
He gained a Bachelor of Science with first class honours in 1954 and a PhD in plant polysaccharides in 1957, under Professor Gerald Aspinall.
Academic career
Appointed to a teaching position at Birkbeck College, University of London, Ferrier's focus turned from polysaccharides to monosaccharides. New laboratory tools and methods enabled their reactions and mechanisms to be studied like normal organic compounds, rather than a separate field, and he pioneered this approach. In the early 1960s as a NATO Post Doctoral Fellow, he worked in Professor Melvin Calvin’s group at the University of California, Berkeley. They were exciting times. While Ferrier was there, Calvin was awarded the Nobel Prize for Chemistry, and he also met Carolyn Tompkins, the pair marrying in Edinburgh in 1962.
Arriving in New Zealand in 1970 as Victoria University’s first chair of organic chemistry, Ferrier continued to lead work on the monosaccharides, specialising in their use as starting materials for the synthesis of non-carbohydrate compounds of pharmaceutical interest. He had previously clarified the mechanism of the Fischer glycosidation and discovered an allylic rearrangement reaction of glycals, now known as the Ferrier rearrangement – the first of two reactions that bear his name. Many of Ferrier's best discoveries were made by following up unexpected chemical observations, which often led him into uncharted territory. His second ‘name’ reaction, the Ferrier carbocyclization, was the result of this approach.
He served on the Toxic Substances Board in the 1980s and the leadership of the RSNZ report Lead in the Environment that confirmed the toxic effects of lead and began the phase-out of leaded petrol.
After his retirement from Victoria University in 1998, he became an emeritus professor. Ferrier then entered what he referred to as his 'supposed retirement', working with the carbohydrate chemists at Industrial Research Ltd. Here he continued to foster the next generation of carbohydrate chemists in New Zealand – his 'grandchildren', instilling his rigorous approach to chemistry with mentoring and assistance with the group's publications.
Ferrier Research Institute
The Ferrier Research Institute at Victoria University of Wellington was named for Ferrier. It was created on 6 January 2014 to accommodate the group of carbohydrate chemists who left Callaghan Innovation on that date. (Callaghan Innovation was previously Industrial Research Ltd.)
Ferrier Lecture
In August 2012, Ferrier celebrated his 80th birthday and retired a second time. Later that year, the Ferrier Trust was set up in his honour, to bring a scientist to New Zealand each year, to engage with chemistry students and lecture. Peppi Prasit, a Ferrier PhD graduate and founder of Amira Pharmaceuticals and Inception Sciences in the US, was the trust's foundation donor. He was able to attend the inaugural Ferrier Lecture in March 2013.
Publications
In his 50-year career, Ferrier published 180 papers, reviews and books, and gave 10 invited plenary lectures at international symposia. His reviews were of particular benefit to the chemical community but perhaps of most value was the book "Monosaccharide Chemistry, written with Dr Peter Collins in 1972 and majorly updated as "Monosaccharides: Their chemistry and their roles in natural products in 1995.
Awards
Ferrier was elected Fellow of the Royal Society of New Zealand (1977) and the New Zealand Institute of Chemistry (1972) and awarded a DSc (London, 1968).
References
1932 births
2013 deaths
Scottish chemists
Organic chemists
People educated at George Heriot's School
Academic staff of Victoria University of Wellington
Scottish twins
Scottish emigrants to New Zealand
Academics of the University of London
Fellows of the Royal Society of New Zealand
Fellows of the New Zealand Institute of Chemistry
Scientists from Edinburgh
Alumni of the University of Edinburgh
University of California, Berkeley faculty
Scottish expatriates in the United States | Robin Ferrier | [
"Chemistry"
] | 1,058 | [
"Organic chemists",
"New Zealand organic chemists"
] |
41,335,850 | https://en.wikipedia.org/wiki/UNESCO%20Niels%20Bohr%20Medal | The UNESCO Niels Bohr Medal was first minted in 1985 to commemorate the 100th anniversary of the birth of the Danish nuclear physicist Niels Bohr. It is awarded by UNESCO to recognise those who have made outstanding contributions to physics through research that has or could have a significant influence on the world.
The medal
In 1985, the 100th anniversary of the birth of Niels Bohr, UNESCO minted a gold medal to commemorate the father of quantum physics and one of the most eminent scientists of the 20th century. Sculpted by Siv Holme-Muse of Sweden, the medal bears the profile of Bohr while the rear depicts his drawing of electrons orbiting around an atomic structure, his formula E2-E1=hy2 representing electrons in relation to hydrogen, and his signature. It also bears the inscription: Contraria sunt complementa (Opposites are complementary), Bohr's principle of complementarity.
2013 awards
Jimmy Wales of Wikipedia was one of the three celebrities who were presented with the medal for 2013 at an event in honour of the 100th anniversary of Bohr's atomic model. The other two were the German particle physicist and director of CERN Rolf-Dieter Heuer, who accepted the medal on behalf of the CERN laboratory, and the French physicist Alain Aspect, noted for his work on quantum entanglement. The medals were presented at the University of Copenhagen conference on "An Open World" on 5 December 2013 by Princess Marie of Denmark. In connection with the ceremony, Wales participated in the session "The Internet: A Global Infrastructure of Openness?" with a presentation titled "Wikipedia, Democracy and the Internet".
Recipients
Recipients of the UNESCO gold medal include:
1998
Vitaly Ginzburg
Walter Kohn
2005
Martin Rees
Herwig Schopper
Peter Zoller
2010
John Pendry
Timothy Berners-Lee
Kip S. Thorne
2013
Alain Aspect
CERN (presented to Rolf-Dieter Heuer)
Jimmy Wales
See also
List of engineering awards
List of physics awards
Niels Bohr International Gold Medal
References
Engineering awards
Physics awards
Awards established in 1955
UNESCO awards | UNESCO Niels Bohr Medal | [
"Technology"
] | 422 | [
"Science and technology awards",
"Engineering awards",
"Physics awards"
] |
41,336,215 | https://en.wikipedia.org/wiki/ACG%20%28subculture%29 | ACG ("Animation, Comics, and Games") is a term used in some subcultures of Greater China and East Asia. Because there is a strong economic and cultural interlinkage that exists between anime, manga, and games in Japanese and East Asian culture at large, the term ACG is used to describe this phenomenon in relative fields. The term refers in particular to Japanese anime, manga, and video games. The term is not normally translated into Chinese; if the meaning needs to be translated, it is usually "two-dimensional space" (, Èr cìyuán; )
Etymology
In 1995, a Taiwanese fan of animation and comics using the name "AIplus" established a board at National Sun Yat-sen University's BBS; the board was named the "ACG_Review Board", referring to animation, comics, and games. It is considered the first appearance of the term "ACG". Popularizing by Taiwanese anime and comics critique group Shuffle Alliance, the arrangement of the three letters was stabilized, and the term became popular in Mainland China, Hong Kong, Macau and Taiwan.
After light novels, which are often adapted into anime, comics, and video games, became more popular, the term "ACGN" was coined. However, the term ACG is still used in the majority of situations and is generally thought to include light novels even without "N."
In other regions
Japanese do not use the term ACG, though a similar concept is "MAG", meaning "Manga, Anime, and Games". Japanese speakers usually use to refer to a series of anime and manga culture (containing light novels and garage kits). The refers to the related subculture, while refers to related industries.
In India, "AVGC" is used instead, meaning "Animation, Visual Effects, Gaming, and Comics".
Though the term is common in Sinophone-speaking areas and East Asia, it is not prevalent in the Anglosphere.
See also
Anime and manga fandom
Cosplay
Doujin
Glossary of anime and manga
Otaku
References
Anime and manga terminology
Chinglish
Comics terminology
National Sun Yat-sen University
Video game terminology | ACG (subculture) | [
"Technology"
] | 444 | [
"Computing terminology",
"Video game terminology"
] |
41,336,517 | https://en.wikipedia.org/wiki/DelFly | The DelFly is a fully controllable camera-equipped flapping wing Micro Air Vehicle or Ornithopter developed at the Micro Air Vehicle Lab of the Delft University of Technology in collaboration with Wageningen University.
The DelFly project focuses on fully functioning systems and follows a top-down approach toward ever smaller and more autonomous flapping wing MAVs.
The DelFly Micro with its 10 cm wing span and 3.07 grams is the smallest free flying controllable flapping
wing MAV equipped with a camera and video transmitter. Smaller flapping wing MAVs exist, but then without an onboard camera. In particular, a hobbyist from Albany NY, built a flapping
wing MAV of 920 mg and just 60mm wing span, which is the world's smallest free flying flapper till date.
The 28 centimeter 16 gram DelFly II was capable of vertical take-off and landing and demonstrated simplified forms of autonomous flight, mainly using off-board processing.
The DelFly Explorer measures 28 centimeter while weighing 20 grams and is equipped with a miniature stereo vision system for autonomous flight in buildings.
The DelFly Nimble is a very agile, tailless flapping wing MAV. It steers by modifying the motions of its wings, which allows it to perform high-speed maneuvers such as 360-degree flips. One of its uses is in studying insect flight; mimicking the extremely fast escape maneuvers of fruit flies revealed a new aerodynamic mechanism that helps to make rapid banked turns. The startup company Flapper Drones is developing a commercial version of the DelFly Nimble for applications within the entertainment sector (drone shows, festivals, theme parks).
History
The DelFly project started in 2005 as a Design Synthesis Exercise for a group of Bachelor of Science students at the Faculty of Aerospace Engineering of the TU Delft. The flapping wing design was mentored by Wageningen University, the remote control and micro camera integration by Ruijsink Dynamic Engineering, and the real-time image processing by the TU Delft. The result of this exercise was the DelFly I, a 50 cm wingspan, 21 grams flapping wing MAV equipped with a camera. The DelFly I was
able to fly both fast and perform slow hovering flight while providing reasonably stable camera images.
In 2007, the DelFly II was created: a 28 cm wing span 16 gram flapping wing MAV equipped with onboard camera. This version was not only smaller, but it had a much broader flight envelope ranging from 7 m/s forward flight to near hovering flight and even backward flight at -1 m/s. In contrast to the DelFly I, the DelFly II could take-off and land vertically. The flight time of the DelFly II was around 15 minutes.
The DelFly II was followed in 2008 by the DelFly Micro, a 10 cm wing span, 3.07 gram flapping wing MAV, also equipped with camera. The DelFly Micro
is fully steerable with 3 controls for the throttle, elevator and rudder. Given the limited onboard energy, the flight time of the DelFly Micro was around 2 to 3 minutes. The DelFly Micro featured in the Guinness book of records 2009 as the smallest airplane in the world equipped with a camera.
The DelFly participated in the 2005, 2007, 2008, 2010 and 2013 editions of the Micro Air Vehicle Competitions and was the first vehicle to demonstrate fully autonomous indoor flight.
The DelFly Explorer was created in 2013. It has a stereo vision system that allows autonomous obstacle avoidance even in unknown and unprepared environments.
The DelFly Nimble, presented in 2018, is the first tailless DelFly. It is much more agile than earlier designs; it can hover and fly in any direction up until 7 m/s in forward flight. It has a relatively simple design and is based on commercially of the shelf components and 3D printed parts.
In 2019, a technological spinoff of the Delft University of Technology Flapper Drones developing a commercial version of the DelFly Nimble was founded.
Influence
The DelFly is based on scaling relations for the aerodynamic design of flapping wings, which were discovered in the Dickinson lab at Caltech in collaboration with Wageningen University. Earlier research in the Dickinson lab also inspired The Robobee, both the Robobee and the DelFly design originated from research with robot models of flying insects. The DelFly influenced the TechJect Dragonfly UAV and FlyTech Dragonfly among many others refer to DelFly developments.
Design challenges
The design of autonomous, light-weight, less than 20 grams flapping wing MAVs poses challenges in various domains, including materials, electronics, control, aerodynamics, computer vision and artificial intelligence. All these domains feed into each other. For example, studies on the design and aerodynamics of the wings have enhanced the efficiency of flight and the amount of generated lift. This allows for a larger payload to be taken on board, such as more onboard sensors and processing. In turn, such onboard processing can be used to perform automatic maneuvers in a wind tunnel, helping to create better models the DelFly and its low Reynolds aerodynamics.
Applications
Flapping wing MAVs have a natural appearance and are inherently safe by means of their low weight and low speeds of the wings. This makes them particularly suitable for indoor flight, also in the presence of humans. Further, flapping wing MAVs can be used as (augmented reality) toys, but other possible applications include inspection of indoor industrial structures or video streaming of the crowd during indoor events. The DelFly flies well indoors with the air conditioning turned off, and outdoors under very low wind conditions.
The exceptional flight capabilities of the DelFly Nimble, combined with its inherent safety and natural appearance, opened up new applications within the entertainment sector. The startup company Flapper Drones is developing the technology further for drone shows during concerts, festivals and within theme parks.
References
2013 robots
Unmanned aerial vehicles of the Netherlands
Robotic animals
Ornithopters
Audiovisual introductions in 2005
Micro robots
Aerial photography | DelFly | [
"Materials_science",
"Biology"
] | 1,226 | [
"Micro robots",
"Animals",
"Robotic animals",
"Microtechnology"
] |
41,336,594 | https://en.wikipedia.org/wiki/Monochromatic%20wavelength%20dispersive%20x-ray%20fluorescence | Monochromatic wavelength dispersive x-ray fluorescence (MWD XRF) is an enhanced version of conventional wavelength-dispersive X-ray spectroscopy (WDXRF) elemental analysis. The key difference is that MWD XRF uses a doubly curved crystal X-ray optic between the X-ray source and the sample resulting in monochromatic excitation. This additional optic creates a high-intensity X-ray beam on a small spot size without increasing the power of the X-ray source. An MWD XRF instrument is constructed from a low-power X-ray tube, a point-to-point focusing optic for excitation, a sample cell, a focusing optic that collects the fluorescence from the sample, and an X-ray detector. By using an optic between the X-ray source and the sample, a monochromatic beam free of bremsstrahlung, excites the sample, eliciting the secondary fluorescence X-rays needed for elemental analysis. By restricting the band of wavelengths used for excitation, a much higher signal to background ratio is achieved. This type of excitation allows much lower limits of detection and faster reading times.
References
X-ray spectroscopy | Monochromatic wavelength dispersive x-ray fluorescence | [
"Physics",
"Chemistry",
"Astronomy"
] | 257 | [
"Spectroscopy stubs",
"Spectrum (physical sciences)",
"Astronomy stubs",
"X-ray spectroscopy",
"Molecular physics stubs",
"Spectroscopy",
"Physical chemistry stubs"
] |
41,336,612 | https://en.wikipedia.org/wiki/Provisional%20Low%20Temperature%20Scale%20of%202000 | The Provisional Low Temperature Scale of 2000 (PLTS-2000) is an equipment calibration standard for making measurements of very low temperatures, in the range of 0.9 mK (millikelvin) to 1 K, adopted by the International Committee for Weights and Measures in October 2000. It is based on the melting pressure of solidified helium-3.
At these low temperatures, the melting pressure of helium-3 varies from about 2.9 MPa to nearly 4.0 MPa. At the temperature of approximately 315 mK, a minimum of pressure (2.9 MPa) occurs. Although this gives a disadvantage of non-monotonicity, in that two different temperatures can give the same pressure, the scale is otherwise robust since the melting pressure of helium-3 is insensitive to many experimental factors.
See also
International Temperature Scale of 1990 (ITS-90) — the calibration standard used for all temperatures above 0.6 K
Leiden scale
References
Temperature
Scales of temperature | Provisional Low Temperature Scale of 2000 | [
"Physics",
"Chemistry",
"Mathematics"
] | 203 | [
"Scales of temperature",
"Temperature",
"Scalar physical quantities",
"Thermodynamic properties",
"Physical quantities",
"SI base quantities",
"Intensive quantities",
"Quantity",
"Thermodynamics",
"Wikipedia categories named after physical quantities"
] |
41,336,708 | https://en.wikipedia.org/wiki/German%20Centre%20for%20Integrative%20Biodiversity%20Research%20%28iDiv%29 | The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig is a DFG research center with staff and members at its main locations in Halle, Jena and Leipzig. It is a central facility of Leipzig University, and is run together with the Martin Luther University Halle-Wittenberg and Friedrich Schiller University Jena, as well as in cooperation with the Helmholtz Centre for Environmental Research - UFZ. In addition, seven non-university research institutions belong to the iDiv consortium. iDiv was founded in 2012 and is funded by the DFG.
History
Due to a great need for research to facilitate implementation of the National Strategy on Biological Diversity, the DFG developed the idea of having its own collaborative research centre for biodiversity. Finally, an institution in the form of a DFG research centre was decided upon.
In the time leading up to October 2010, 15 universities applied to the DFG for establishment of the research centre. The concepts of the FU Berlin, the University of Göttingen, the University Network Halle-Jena-Leipzig and the University of Oldenburg were preselected in July 2011 by the DFG Senate. The FU Berlin and the University Network Halle-Jena-Leipzig were then shortlisted.
On April 27, 2012, came the decision in favour of the University Network Halle-Jena-Leipzig and for the establishment of the core centre at the Leipzig location. At its meeting in Bonn, the DFG's central committee selected the joint application of the Universities of Halle, Jena and Leipzig on the recommendation of the DFG Senate. The scientific and structural conditions at the three neighbouring locations are excellent, and the fact that they already had a strong reputation and had conducted numerous, in some instances internationally oriented research projects in the field of biodiversity science before the opening of the research centre influenced the DFG in its decision. In addition, eight non-university research institutions are involved in the new centre: the Helmholtz Centre for Environmental Research - UFZ, the Max Planck Institute for Biogeochemistry, the Max Planck Institute for Chemical Ecology, the Max Planck Institute for Evolutionary Anthropology, the Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, the Leibniz Institute of Plant Biochemistry, the Leibniz Institute of Plant Genetics and Crop Plant Research and the Leibniz Institute Senckenberg Museum of Natural History Görlitz (SMNG).
In autumn 2012, the centre moved to the Biocity at Deutscher Platz 5 in the southeast of the city of Leipzig.
iDiv moved into a new building at the Alte Messe area in 2021.
Financing
The DFG funds iDiv in the current, second funding period (2016-2020) with approximately 9 million euros annually. This represents an increase of 32 percent compared to the first funding period. In addition, the partners in the iDiv consortium make their own contributions and there are also third-party grants for individual research projects. The DFG usually funds DFG research centres such as iDiv for three four-year periods.
Research
Biodiversity research at iDiv takes place against the backdrop of the current biodiversity crisis. The magnitude of it, the underlying processes and consequences for humanity are often unknown. In order to better understand the complex interactions, iDiv research prioritises synthesis, theory and transdisciplinarity. iDiv has two missions:
First, to provide a scientific basis for the sustainable use of our planet's biodiversity.
Second, to develop a new field of research: ‘Integrative Biodiversity Research’
Staff and structure
iDiv has four speakers, which are currently Christian Wirth (representing Leipzig University), Nicole van Dam (representing Friedrich Schiller University Jena), Henrique Miguel Pereira (representing Martin Luther University Halle-Wittenberg) and Tiffany M. Knight (representing the Helmholtz Centre for Environmental Research – UFZ).
To date, nine full professors have been appointed:
• Experimental Interaction Ecology (Nico Eisenhauer)
• Biodiversity Conservation (Henrique Miguel Pereira)
• Ecosystem Services (Aletta Bonn)
• Molecular Interaction Ecology (Nicole van Dam)
• Physiological Diversity (Stanley Harpole)
• Biodiversity Synthesis (Jonathan Chase)
• Theory in Biodiversity Sciences (Ulrich Brose)
• Spatial Interaction Ecology (Tiffany M. Knight)
In addition, there are several other units operating at iDiv: In the sDiv Synthesis Centre, scientists from all over the world come together in so-called working groups in order to gain new insight from existing knowledge and data. The aim of the graduate school, yDiv (Young BioDiversity Research Training Group) is to train a new generation of interdisciplinary biodiversity scientists. Scientific coordination promotes integration among the working groups and iDiv members who are located throughout Central Germany. IT Support, Bioinformatics (BIU) and Biodiversity Informatics (BDU) ensure the storage, provision and analysis of data. The administration team takes care of purchasing, finance, human resources and infrastructure. The Department of Media and Communication promotes dialogue with politics and society.
References
External links
Biodiversity | German Centre for Integrative Biodiversity Research (iDiv) | [
"Biology"
] | 1,039 | [
"Biodiversity"
] |
41,336,858 | https://en.wikipedia.org/wiki/Inhibitor%20cystine%20knot | An inhibitor cystine knot (also known as ICK or Knottin) is a protein structural motif containing three disulfide bridges. Knottins are one of three folds in the cystine knot motif; the other closely related knots are the growth factor cystine knot (GFCK) and the cyclic cystine knot (CCK; cyclotide). Types include a) cyclic mobius, b) cyclic bracelet, c) acyclic inhibitor knottins. Cystine knot motifs are found frequently in nature in a plethora of plants, animals, and fungi and serve diverse functions from appetite suppression to anti-fungal activity.
Along with the sections of polypeptide between them, two disulfides form a loop through which the third disulfide bond (linking the 3rd and 6th cysteine in the sequence) passes, forming a knot. The motif is common in invertebrate toxins such as those from arachnids and molluscs. The motif is also found in some inhibitor proteins found in plants, but the plant and animal motifs are thought to be a product of convergent evolution. The ICK motif is a very stable protein structure which is resistant to heat denaturation and proteolysis.
CK peptide components of venoms target voltage-gated ion channels but members of the family also act as antibacterial and haemolytic agents. Plant ICK proteins are often protease inhibitors.
Knottins have high stability to pH, heat, and enzymes. Because of their stability and their favorable pharmacodynamic properties, knottins are becoming increasingly popular as protein engineering scaffolds. Moreover, engineered knottins have shown significant promise as therapeutics, imaging agents, and targeting agents for chemotherapy.
The mammalian proteins Agouti signalling peptide and Agouti related peptide are the only known mammalian examples of this motif. Both are neuropeptides involved in cell signalling. The former is responsible for hair (fur) colouration.
The motif is similar to the cyclic cystine knot or cyclotide, but lacks the cyclisation of the polypeptide backbone which is present in the latter family. The growth factor cystine knot (GFCK) is similar to the ICK but its topology is such that it is the bond between the first and fourth disulfide which threads through the loop.
Proteins which contain the ICK motif
Agouti related peptide
Agouti signalling peptide
Albumin I
Covalitoxin-II
DkTx
Grammotoxin
GsMTx-4
Guangxitoxin
Hainantoxin
Hanatoxin
Heteroscodratoxin-1
Huwentoxin
Maurocalcine
Theraphosa leblondi toxin
δ-Palutoxin
Phrixotoxin
Psalmotoxin
Robustoxin
Stromatoxin
Tachystatin
Vanillotoxin
Vejocalcin
References
External links
The cyclotide webpage
The KNOTTIN Database
Protein structure
Neurotoxins
Ion channel toxins
Protein folds
Cysteine-rich proteins | Inhibitor cystine knot | [
"Chemistry",
"Biology"
] | 633 | [
"Neurotoxins",
"Protein classification",
"Cysteine-rich proteins",
"Structural biology",
"Neurochemistry",
"Protein structure"
] |
41,337,332 | https://en.wikipedia.org/wiki/Azenta | Azenta, (formerly Brooks Automation) was founded in 1978, and is based in Chelmsford, Massachusetts, United States. The company is a provider of life sciences services including genomics, cryogenic storage, automation, and informatics.
History
Brooks Automation was set up in 1978, and incorporated in 1994.
Brooks acquired the German company Jenoptik-Infab GmbH, subsidiary of M+W Zander, in 1999 to incorporate its mini-environment technology for 300 mm wafer handling.
In 2002, Brooks Automation, Inc. completed the acquisition of Intelligent Automation Systems, Inc. of Cambridge, Massachusetts, a custom automation company with technology and products for the semiconductor, photonics and life sciences industries.
Brooks Automation acquired the Celigo automated Cell Cytometer product line from Cyntellect, Inc in 2011. The same year, Brooks acquired Nexus Biosystems, which produced compound and sample management systems. The following year the company acquired intangible assets from Intevac, Inc. and acquired Crossing Automation Inc.
In October 2012, Brooks Automation entered into an agreement to acquire Crossing Automation Inc.
In April 2014, Brooks Automation entered into an agreement to sell its Granville-Phillips division to MKS Instruments.
Brooks closed the sale of Granville-Phillips to MKS Instruments on May 30, 2014.
Brooks automation announced the acquisition of Biostorage Technologies on 1 December 2015.
In 2017, Brooks acquired 4titude, a maker of scientific tools and consumables, while in 2018, Brooks acquired GENEWIZ, a genomics services provider as part of their life sciences division's expansion.
In November 2021, Brooks Automation Inc. split into two entities, Brooks Automation and Azenta Life Sciences. The latter will focus exclusively on their life science division.
In August 2022, Azenta Life Sciences has come to a definitive agreement to acquire B Medical Systems S.á.r.l., in a transaction of approx. €410 million (with an additional €50 million in future performance milestones) is expected to be completed by October 2022.
Business
Brooks Automation operates in three segments: Brooks Product Solutions, Brooks Global Services, and Brooks Life Science Systems.
Brooks Automation provides mainly four kinds: semiconductor automation and life science systems equipment, gas analysis and vacuum measurement, cryopumps, cryochillers and compressors, asset tracking equipment. The company features in developing and building the handling system and related technology. Automation products are used to support both atmospheric and vacuum based processes while the company's focus remains on improving performance and productivity. The company provides vacuum pumps and instrumentation to maintain pressure consistency of the known process gas. The Brooks Life Science Systems provides automated sample management systems and equipment, such as automated blood fractionation equipment, cellular imaging, and consumables parts.
Research and development
In January 2012, Brooks Automation announced that it had acquired the Celigo Cell Cytometer product line from Cyntellect Inc. Celigo had an advantage in cell imaging systems based on its unique combination of high-throughput, ease-of-use, and affordability.
In April 2012, Brooks Automation announced the Polycold Systems XC Cryochiller (a multi-purpose cooler) product line and set a new standard in the industry. With the new production line put into use in vacuum and thermal management applications, it would greatly increase water vapor pumping speed and decrease the operating costs.
In July 2013, Brooks Automation announced that it had signed a definitive agreement to acquire the assets and business of Matrical, Inc.($10 million) to expand the Brooks Life Science Systems business. Matrical focuses on biological sample preparation, management, and storage solutions.
Awards
Brooks Automation won the R&D 100 award (100 most technologically significant new products introduced) by R&D Magazine for its Model 830 Vacuum Quality Monitor (VQMTM). VQMTM was used to determine gas composition with an electrostatic autoresonant ion trap.
References
External links
Life science companies based in Massachusetts
Technology companies based in Massachusetts
Manufacturing companies based in Massachusetts
Companies based in Middlesex County, Massachusetts
Manufacturing companies established in 1978
Technology companies established in 1978
1978 establishments in Massachusetts
Companies listed on the Nasdaq | Azenta | [
"Biology"
] | 864 | [
"Life science companies based in Massachusetts",
"Life sciences industry"
] |
41,337,449 | https://en.wikipedia.org/wiki/MoFEM%20JosePH | MoFEM (Mesh Orientated Finite Element Method) is an open source finite element analysis code developed and maintained at the University of Glasgow. MoFEM is tailored for the solution of multi-physics problems with arbitrary levels of approximation, different levels of mesh refinement and optimised for high-performance computing. MoFEM is the blend of the Boost (C++ libraries) MultiIndex containers, MOAB (Mesh Oriented Database) and PETSc (Portable, Extensible Toolkit for Scientific Computation). MoFEM is developed in C++ and it is open-source software under the GNU Lesser General Public License (GPL).
Motivation
Building a scientific simulation environment for finite element methods is a complicated task. The longest part of finite element code development is in dealing with technical problems related to software implementation, rather than resolving the underlying physics that the code is intended to tackle.
The demand for accurate solutions of increasingly complicated real-world problems means that the underlying data structures also become increasingly complicated. This is particularly evident with multi-physics, hp-adaptivity, and/or evolving geometries (e.g. crack propagation). Established commercial software is often limited in this respect, or can be relatively slow to adopt new innovations. Working around these problems has been the main motivation for the development of MoFEM, recognising that it is increasingly necessary for engineers, scientists and mathematicians to carry out calculations using several mesh refinements, different approximation orders, multiple degrees of freedom and/or different scales.
History
MoFEM evolved from YAFEMS (2008), a general and open source finite element code developed at the University of Glasgow.
In 2013 YAFEMS was re-written from scratch and named MoFEM. MoFEM was initiated by two projects. EPSRC founded a project for Providing Confidence in Durable Composites (DURACOMP) in a consortium of three institutions: University of Warwick, University of Glasgow, Newcastle University and several industrial partners. The second project was funded by IAA-EPSRC: Simulation of fracture in nuclear graphite: from academic setting to commercial application and EDF Energy.
Main features
Solves various linear and nonlinear problems from structural, thermal and fluid mechanics
Efficient parallel processing support based on domain decomposition and message passing paradigms.
Direct as well as iterative solvers are available. Interfaces to PETSc third party linear, nonlinear at time dependent solvers.
Adaptive mesh refinement base on edge based refinement algorithm
Supports hierarchical approximation basis for L2, H1, H-div and H-curl spaces
Calculate stress intensity factors and crack propagation based on configurational mechanics
Arbitrary Lagrangian Formulation with Mesh Smoothing Algorithms based on Volume-Length quality tetrahedral element measure with barrier
License
MoFEM is free, open source software, released under the GNU Lesser General Public License as published by the Free Software Foundation.
References
External links
MoFEM Bitbucket Repository
MOAB
Engineering and Physical Sciences Research Council
Finite element software
Scientific simulation software
Free computer-aided design software
Free software programmed in C++
Computational physics
Free science software
Finite element software for Linux
University of Glasgow | MoFEM JosePH | [
"Physics"
] | 640 | [
"Computational physics"
] |
41,337,508 | https://en.wikipedia.org/wiki/Fireboats%20of%20Jamaica | The Jamaican Fire Brigade operates several fireboats of Jamaica.
According to a 2003 article in the Jamaica Gleaner the three fireboats then nominally operated by the Fire Brigade were all in a state of disrepair, and had all been out of service for months—or in the case of one vessel—years. According to another Gleaner article the stations were dangerously over-run with rats and other vermin.
In 2005 the Jamaica Star reported that after the fireboat assigned to the Kingston Fire Boat Station had been out of service for most of 2004—being sent for repair four separate times, the staff were assigned to other duties when the fireboat was placed permanently offline.
By 2012, the fireboat that served Montego Bay, Jamaica's second most important port, had been without a fireboat for over five years, as the previous boat had been written off as not worth repairing, but had yet to be replaced.
Both the mayor of Montego Bay, Glendon Harris, and Jamaica Senator Robert Montague have called for the urgent supply of new fireboats.
In November 2013 Alrick Hacker a Senior Deputy Superintendent of the Fire Brigade, defended the Brigade's replacement plans and outlined the interim measures in place until the new boats were in service.
Jamaica's three new Jamaican Coast Guard patrol cutters all mount a water cannon in their bow, and Hacker said the Coast Guard had been requested to help out until the Brigade's new fireboats were ready. He said the Police Marine units also had some firefighting capability, and they too had been asked to help out. He asserted that modern cruise ships, the foreign vessels of most acute concern, were built more fire-safe than in the past, and had the capability to fight their own fires, to a certain extent.
Hacker asserted that new technology would allow the Fire Brigade to replace their older, relatively large vessels with smaller, faster, more capable vessels, that would be cheaper to operate and to maintain.
In 2018 the Fire Brigade acquired two new fireboats.
References
Fire | Fireboats of Jamaica | [
"Chemistry"
] | 411 | [
"Combustion",
"Fire"
] |
41,337,708 | https://en.wikipedia.org/wiki/Perfluorotributylamine | Perfluorotributylamine (PFTBA), also referred to as FC43, is an organic compound with the chemical formula . It is a colorless liquid. A molecule of this chemical compound consists of three butyl groups connected to one nitrogen atom, in which all of the hydrogen atoms are replaced with fluorine atoms. The compound is produced for the electronics industry, along with other perfluoroalkylamines. The high degree of fluorination significantly reduces the basicity of the central amine due to electron-withdrawing effects.
Preparation
It is prepared by electrofluorination of tributylamine using hydrogen fluoride as solvent and source of fluorine:
Uses
The compound has two commercial uses.
It is used as an ingredient in Fluosol, artificial blood. This application exploits the high solubility of oxygen and carbon dioxide in the solvent, as well as the low viscosity and toxicity. It is also a component of Fluorinert coolant liquids. CPUs of some computers are immersed in this liquid to facilitate cooling.
Niche
The compound is used as a calibrant in gas chromatography when the analytical technique uses mass spectrometry as a detector to identify and quantify chemical compounds in gases or liquids. When undergoing ionization in the mass spectrometer, the compound decomposes in a repeatable pattern to form fragments of specific masses, which can be used to tune the mass response and accuracy of the mass spectrometer. Most commonly used ions are those with approximate mass of 69, 131, 219, 414 and 502 atomic mass units.
Safety
Fluorofluids are generally of very low toxicity, so much that they have been evaluated as synthetic blood.
Environmental impact
It is a greenhouse gas with warming properties more than 7,000 times that of carbon dioxide over a 100-year period, and, as such, is one of the most potent greenhouse gasses ever discovered. Its concentration in the atmosphere is approximately 0.18 parts per trillion. The compound can persist in the atmosphere for up to 500 years.
See also
Perfluorotripentylamine
References
Greenhouse gases
Perfluorinated compounds
Amines
Coolants | Perfluorotributylamine | [
"Chemistry",
"Environmental_science"
] | 455 | [
"Environmental chemistry",
"Functional groups",
"Greenhouse gases",
"Amines",
"Bases (chemistry)"
] |
41,337,714 | https://en.wikipedia.org/wiki/Far%20Cry%204 | Far Cry 4 is a 2014 first-person shooter game developed by Ubisoft Montreal and published by Ubisoft. It is the successor to the 2012 video game Far Cry 3, and the fourth main installment in the Far Cry series. Set in the fictional Himalayan country of Kyrat, the game follows Ajay Ghale, a young Kyrati-American, who becomes caught in a Civil war between Kyrat's Royal Army, controlled by the tyrannical king Pagan Min, and a rebel movement called the Golden Path. The gameplay focuses on combat and open world exploration; players battle enemy soldiers and dangerous wildlife using a wide array of weapons. The game features many elements found in role-playing games, such as a branching storyline and side quests. The game also features a map editor and both cooperative and competitive multiplayer modes.
Announced in May 2014, development on Far Cry 4 began immediately after the shipment of Assassin's Creed III in late 2012. The team originally intended to develop a direct sequel to Far Cry 3 that continues the narrative, but the idea was later scrapped and the team decided to develop a new setting and story for the game. Certain aspects of Far Cry 4 were inspired by the Nepalese Civil War, and the design of the game's antagonist Pagan Min was inspired by Japanese films Ichi the Killer and Brother. Troy Baker was hired to portray Pagan Min. The game's competitive multiplayer was created by Red Storm Entertainment while the Shangri-La segments in the campaign were handled by Ubisoft Toronto.
Far Cry 4 was released worldwide for PlayStation 3, PlayStation 4, Windows, Xbox 360, and Xbox One in November 2014. It received mostly positive reviews, with critics praising the open-world design, visuals, soundtrack, and characters as well as new gameplay additions and the wealth of content. However, some reviewers disliked the story and found the game too similar to its predecessor. The game sold over 10 million units by March 2020. Several releases of downloadable content were subsequently published. A spin-off title, Far Cry Primal, was released in February 2016. A successor, Far Cry 5, was released in March 2018.
Gameplay
Far Cry 4 is a first-person action-adventure game. Players assume control of Ajay Ghale, a Kyrati-American who is on a quest to spread his deceased mother's ashes in the fictional country of Kyrat. Ajay may utilize various short and long-range firearms, including pistols, revolvers, shotguns, assault rifles, submachine guns, bows, a flamethrower, rocket launchers, grenade launchers, and sniper rifles. More powerful versions of these weapons become available after considerable progress through the game. Throwable weapons include fragmentation grenades, Molotov cocktails, and throwing knives. The game allows players to take cover to avoid gunfights and to perform melee takedowns from above or up-close. Unlike previous installments in the series, Far Cry 4 gives players the ability to kick objects and the ability to hide the corpses of enemies.
Players can use a variety of methods to approach missions. For instance, players can utilize stealth to evade enemies and complete objectives without being noticed, or they also have the option to assault enemies with firearms and vehicles. The player character is equipped with a digital camera, which allows him to mark and highlight all visible enemies, animals, and loot. Players are also able to ride on elephants, which serve as tank-like offensive weapons. Players can throw bait towards enemies, which attracts nearby wildlife that is hostile to both the player and enemies. Players can also hunt and skin animals.
The game features an open world environment that is free for players to explore. It features several environments, including forests, rivers, and mountains. To allow players to travel between places faster, the game features various vehicles, including buggies, trucks, and water vehicles like speedboats. Players can drive and shoot at the same time and can enable auto-drive, in which the game's artificial intelligence takes over the role of controlling the vehicle and guides players to their objectives. Players can also hijack other vehicles while driving. The Buzzer, an aerial, gyrocopter-like vehicle, is introduced in the game, allowing players to gain a tactical advantage from the air. Parachutes, wingsuits, and grappling hooks are also featured in the game; these items help players swing across cliffs and quickly navigate the environment. Parts of the game take place in Shangri-La, a mystical dreamland where players battle demons as the Kyrati warrior Kalinag. While in Shangri-La, players are accompanied by an injured tiger which serves as their companion. Players can issue commands to the tiger, which assists them in battle.
The game world is divided into two halves: North and South Kyrat. Players start in South Kyrat and are free to explore it almost immediately, but can only unlock North Kyrat over the course of the story. The map is progressively opened by liberating bell towers, freeing them from Pagan Min's influence and allowing the Golden Path to expand. These towers help players reveal new areas and mark new locations of interest on the map. The world is scattered with outposts controlled by Pagan Min, which can be infiltrated by players. Four larger outposts, or fortresses, can also be found, and feature stronger defenses and more difficult combinations of enemies. If players successfully liberate these outposts, they will serve as fast-travel points, allowing quick navigation through the game's world. Additional missions and quests also become available. There are many side-missions that can be completed, including hostage rescues, bomb disposal quests, and hunting missions. The collected animals' parts can then be used for crafting new pouches and belts.
Like its predecessors, the game features some role-playing elements. Players can earn experience points by completing missions and defeating enemies, and these experience points can then be spent on performance boosts and upgrades. There are two sets of abilities for players to choose from, called The Tiger and The Elephant. The Tiger upgrades mainly improve players' offensive abilities, while The Elephant upgrades improve players' defensive skills. A variety of random events and hostile encounters take place throughout the game; for example, the player may unexpectedly be attacked by an eagle, be hit by a car, or witness an animal attack. Players can accumulate karma by performing kind actions towards the rebels, such as by assisting them in battles when they are attacked by wildlife or enemies. Doing so will give players discounts when purchasing new items at trading posts, and will allow players to call in support and back-up from members of the Golden Path. Players can also gain experience by collecting items like masks, propaganda posters, and prayer wheels. There is also an Arena mode, in which players battle human enemies and animals for additional experience points and rewards.
Multiplayer
Far Cry 4 features a co-operative multiplayer mode known as "Guns for Hire", which supports up to two players. The mode is separated from the game's campaign, and players are free to explore the game's world, defeat enemies, and infiltrate outposts with their companion. In addition to the co-operative mode, players can gain access to several competitive multiplayer modes which have an asymmetrical structure. Players play as either a Rakshasa or a Golden Path member. The Rakshasa are equipped with bows and arrows and have the ability to teleport and summon wildlife to assist them and gain transparency, while Golden Path members are equipped with guns and explosives, and have access to armored vehicles. Known as "Battles of Kyrat", players fight against each other in three modes, called Outpost, Propaganda, and Demon Mask. Far Cry 4 also contains a Map Editor that allows users to create and share custom content. Similar to that of Far Cry 3, players can create their maps by customizing landscapes, and by placing buildings, trees, wildlife, and vehicles. However, the Map Editor did not support competitive multiplayer levels at launch. Multiplayer support was added to the game on February 3, 2015.
Plot
After the death of his mother Ishwari, Ajay Ghale (James A. Woods) returns to his home country of Kyrat to carry out Ishwari's final wish by returning her ashes to Lakshmana. However, his mission is interrupted when the bus he is traveling on is attacked by the Royal Army and he is greeted by Pagan Min (Troy Baker), the country's eccentric and violent king. Min apologizes, brutally kills a soldier for shooting the bus, and acts warmly toward Ajay before kidnapping him and his tour guide and taking them to a dinner party at Lieutenant Paul De Pleur's mansion. After his guide is taken to be interrogated, Ajay flees with the aid of Sabal (Naveen Andrews), a commander in the Golden Path, a rebel movement established by Ajay's father, Mohan Ghale. Ajay is not able to leave the country as the Royal Army has taken control of Kyrat's only airport and sealed the borders.
In the twenty-odd years since Ishwari and Ajay fled Kyrat, the rebellion has stagnated, with the Golden Path now fighting for their very existence. As the son of Mohan Ghale, Ajay becomes a symbol for the Golden Path to rally around. After freeing a group of hostages and liberating territory held by Pagan, the Golden Path plan on breaking Pagan's stranglehold on power by targeting his three regional governors: Paul "De Pleur" Harmon (Travis Willingham), who oversees opium production and runs Pagan's torture chambers; Noore Najjar (Mylène Dinh-Robic), who runs poaching and prostitution rings and who became a victim of Pagan's cruelty herself after he kidnapped her family; and Yuma Lau (Gwendoline Yeo), Min's adopted sister and trusted general who is obsessed with uncovering the secrets of the mystical realm of Shangri-La.
However, the Golden Path's newfound momentum is threatened by deep divisions between its commanders, Sabal, who favors traditional values, and Amita (Janina Gavankar), who argues for progress, which includes relying heavily on producing drugs for export. Ajay is forced to intervene on several occasions, with his decisions influencing the direction the Golden Path takes. The first governor to fall is De Pleur, after Noore helps Ajay find a way to infiltrate De Pleur's stronghold, allowing the rebellion to capture him. Amita and Sabal later task Ajay with confronting and killing Noore. She dies in her fighting arena, either with Ajay killing her, or with Noore committing suicide upon learning Pagan had her family executed years beforehand.
As the Golden Path secures Kyrat's southern provinces, Ajay is contacted by Willis Huntley (Alain Goulem), a CIA agent who offers intelligence for the rebels and pages from his father's diary in exchange for killing Yuma's lieutenants. After Ajay kills several of them, Huntley admits they were in fact CIA assets, and that he was sent to clean up after the CIA as the agency did not see Pagan as a threat anymore. Huntley betrays Ajay to Pagan just as the Golden Path prepares to push into Northern Kyrat.
Ajay ends up in Yuma's mountain prison, where he is drugged and suffers terrifying hallucinations, but manages to escape. In the process, he finds out that Yuma has started despising Pagan, primarily because of his affection toward Ajay's late mother. The Golden Path pushes into the north, and while Ajay attempts to reconnect with another faction of the rebels, Pagan, aware of Yuma's plotting against him, betrays Yuma to the Golden Path. Ajay is drawn into a confrontation with her and prevails, but tensions between Amita and Sabal reach new heights, and Ajay is forced to make a final decision as to who will lead the Golden Path. Whichever leader he chooses then sends Ajay to kill the other to prevent them from starting another civil war, and Ajay can choose to either kill them as ordered or let them go. With the Golden Path now united under a single leader, Ajay joins them for an attack on Pagan's fortress and pushes on alone to Pagan's palace while the Golden Path holds off the military.
Endings
Ajay encounters Pagan, who chastises him for fleeing at the start of the game, claiming that he only ever intended to help Ajay. Pagan offers Ajay a final decision: shoot him now or listen to him. If Ajay shoots Pagan, the game ends immediately and the credits roll. If Ajay instead chooses to listen, Pagan reveals that Mohan sent Ishwari to spy on Pagan in the early days of the Golden Path, but they fell in love and had a daughter together: Lakshmana, Ajay's half-sister. Mohan killed Lakshmana for Ishwari's betrayal, and Ishwari killed him in turn before leaving the country with the infant Ajay. Pagan shows Ajay to a shrine containing Lakshmana's ashes, and Ajay places Ishwari's ashes inside. Pagan then boards a helicopter and departs peacefully, leaving the country in Ajay's hands. The player can choose to shoot down Pagan's helicopter as it flies away, killing Pagan in the process.
In the aftermath, the Golden Path seizes control of Kyrat. The final ending depends on which leader Ajay ultimately sided with. If Amita is placed in charge, she turns Kyrat into an authoritarian drug state, forcing villagers into work in factories and drug fields, and conscripting children into the group as soldiers to bolster their ranks against the remnants of the Royal Army; Ajay also learns that she has had her sister, Bhadra, taken away, "never to come again". If Sabal is placed in charge, Kyrat becomes a patriarchal fundamentalist theocracy where all of Amita's supporters are executed, women are denied fundamental political rights, and Bhadra is anointed as a religious symbol for the country to rally around. The player has the choice to kill the Golden Path's leader or leave them alive.
An Easter egg ending can be found at the beginning of the game. To trigger it, Ajay must simply wait at the dinner table in Pagan's mansion; when Pagan returns, he thanks Ajay for being a "gentleman" and leads him to Lakshmana's shrine, telling Ajay of his family history. After Ajay plants his mother's ashes at the shrine, Pagan invites Ajay to join him to "finally shoot some goddamn guns".
Development
The game's development was led by Ubisoft Montreal, which took over the development of the Far Cry franchise after the release of Far Cry: Instincts in 2005. Additional development was handled by four other in-house Ubisoft studios, Ubisoft Toronto, Red Storm Entertainment, Ubisoft Shanghai, and Ubisoft Kyiv. The Montreal studio worked on the game's campaign, the Toronto studio worked on the Shangri-La segments of the campaign, Red Storm handled the development of the competitive multiplayer, the Shanghai studio worked on the hunting missions, and the Kyiv studio developed the game's PC version. Development of the game began in late 2012, after the shipment of Assassin's Creed III. The game's creative director is Alex Hutchinson, who had previously worked on Maxis's Spore as well as Assassin's Creed III. The game runs on an upgraded version of the Dunia 2 engine that was used in Far Cry 3.
Gameplay design
When brainstorming ideas for the new Far Cry game, the development team originally planned on developing a direct sequel to Far Cry 3. The sequel would be set on the same tropical island, would expand upon the protagonist's story, and would bring back characters, such as Far Cry 3's secondary antagonist, Vaas Montenegro. However, after four days, the team found that a sequel was not what they wanted to achieve. As a result, they decided to scrap the idea and build a brand new game with a new setting and a new set of characters. The team adapted a "we want it all" approach, in which they hoped to experiment with all kinds of ideas. Some team members hoped that the game would allow players to fly, which led to the game's verticality. The game's director also hoped that players would be able to ride a rampaging elephant, in a place with "exotic mountainsides" and "unique culture". This led to the concept of a mountainous setting and the introduction of elephants in the game. The developers aimed for players to consider Far Cry 4 a standalone experience, and therefore they avoided bringing back any characters from Far Cry 3 except for Willis and Hurk. The decision to bring the two back was made because the team thought that they should provide some references to previous games in the series, as all of the games are set in the same universe even though they are not directly related.
Some of the gameplay elements were directly taken from Far Cry 3. Exotic locations, hunting, and the freedom for players to complete missions through different approaches were maintained in Far Cry 4. The team hoped that by incorporating and expanding upon these ideas, while introducing new features, they could make Far Cry 4 an evolution for the series. As a result, the size of the game's outposts became larger and players were given more options to customize their weapons. The team also realized that players spent a lot of time interacting with the open world of Far Cry 3, and decided to put more effort and resources into the world's design and add more quests to the game.
Setting and characters
The game's setting, Kyrat, is a fictional country in the Himalayas region. When building Kyrat, the developers merged elements from real-world regions including India, Nepal and Tibet, but exaggerated those elements. The map's size is similar to that of Far Cry 3, but is more dense, diverse, and features more varied environments. The developers hoped that players could experience a sense of exploration when traveling between different terrains. The team also hoped that the new location could be believable while remaining interesting for players. As a result, they created an identity for Kyrat by doing such things as adding different signboards to the game and creating a fictional mythology and religion for Kyrat. The game's world was also designed to accommodate new features such as the helicopter and the grappling hook. In an effort to make the world feel real, the team added improvements to the design of side-quests. Instead of simply being activities for players to complete, the quests are narrative-driven, which was done to increase the connection between them and the world. In order to increase the credibility of the game's world, the studio sent a team to Nepal to experience and record the local culture, so that they could bring those ideas back to the studio. According to the developer, the trip changed the game's design; the focus shifted from the game's civil war, which is inspired by the real-world Nepalese Civil War, to developing unique and interesting characters.
One of the game's most critically acclaimed characters is its major antagonist Pagan Min, a foreign interloper who usurps the rule of Kyrat by its royal family and names himself after the historical Burmese king within series lore. The team hoped that players would be "shocked, amazed and intrigued" by him in every encounter. Min has a complex relationship with the playable character, Ghale, as the team wanted players to guess Min's intentions and add a layer of mystery to him. The team originally hoped to have a villain that had a "punk-rock mentality", but the idea was abandoned as the team thought that the concept was not original. The pink costume Min wears throughout the game was inspired by Beat Takeshi, a character from Brother, and Kakihara, a character from Ichi the Killer. Min is designed to be sadistic yet confident, and the team hired Troy Baker to provide the voice for Min, as they thought that Baker's voice is charismatic enough to suit Min. According to Baker, Ubisoft gave him a script for the audition but he chose not to follow it, and instead decided to threaten to cut off the face of an assistant using Min's tone. The interviewer was very pleased with Baker's performance and decided to sign him for the job. As for Ghale, he was designed to be "thin", and his backstory was designed to be revealed as players progressed through the game's story. According to the game's narrative director, Mark Thompson, Ghale learns the history and culture of Kyrat along with players. The developers also hoped that Ghale could be an accessible character for players.
In hindsight, the team considered the story of Far Cry 3 "great", even though they thought that it was separated from the game's world. In order to increase players' agency and make the story feel more connected to the world for players, the team introduced a branching storyline that required players to make choices that would lead to different results and alter the game's ending. The team hoped that by adding choices, they could add additional depth and meaning to the game's campaign. Thompson added that they twisted the story of Far Cry 3 for Far Cry 4, and made outsiders the villains instead of the heroes. The team considered it a "risk", but they wanted to try something different.
For the Shangri-La mission, the team wanted to have a structure similar to Far Cry 3s mushroom missions; a game within a game. The Shangri-La missions are not related to Kyrat, but play an important role in the game's narrative. When creating these segments, the team put a lot of emphasis on the use of colors. They hoped that the artistic vision for Far Cry 4 would not feature any resemblance to other typical shooter games. It was originally designed to be a small open world but was later converted into a linear experience due to time constraints and huge creative differences between developers. The team later decided to simplify it, and re-imagined it into an "ancient, natural world". It is made up of five different colors. The main color of Shangri-La is gold; the developers thought that using gold as the foundation added "warmth" to the dreamland. Meanwhile, red was used heavily to add a sense of strangeness, as well as for establishing a tie to the game's narrative and story. Orange was used as a color of interaction, while white was used to add purity to the world. Blue is the last of Shangri-La's main colors and represents danger and honor.
Multiplayer
Ubisoft promised that Far Cry 4 would have much more of a multiplayer element than Far Cry 3. Some elements that were scrapped for Far Cry 3 due to time constraints were featured in Far Cry 4, such as the "Guns for Hire" co-operative multiplayer mode. Building a cooperative experience was the team's goal starting from the beginning of the game's development. Originally intended to be a separate mode, it was later made to be seamlessly integrated into the main campaign. The game's competitive multiplayer was designed to give players freedom, allowing players to progress and defeat enemies in a variety of different ways. Red Storm Entertainment also considered players' feedback from the multiplayer aspect of Far Cry 3, and decided to include vehicles in the game. The company chose an asymmetrical structure for this mode so that players could have different experiences in different matches, as well as to make matches feel more chaotic. The developers originally planned to feature female playable characters, but the plan was scrapped due to animation problems. Ubisoft announced a 'Keys to Kyrat' offer for players that owned a copy of the game for the PlayStation 3 or PlayStation 4. It allows those owners to send out game keys to up to ten other people who do not own a copy of the game. Players who are offered a key can join the person that sent them the key and play the cooperative mode for two hours.
Music
Cliff Martinez was hired to work on the game's soundtrack. A two-disc edition was released that contained 30 tracks heard in the game, and a deluxe edition was released that contained 15 extra tracks. The album was released just before the release of the game and received positive reviews. Particular praise was directed towards the usage of traditional Nepalese instruments which, combined with electronic samples, suggested high octane action and mystical wondering.
Release
With Far Cry 3 being a commercial success, Ubisoft considered the Far Cry series one of their most important brands, and they hinted that a sequel was in development in June 2013. On October 3, 2013, Martinez mentioned that he was working on the soundtrack for the game. In March 2014 the game's setting and features were leaked. The game was officially announced on May 15, 2014, and the first gameplay footage was revealed during Electronic Entertainment Expo 2014. The game's cover art, which shows the light-skinned Pagan Min resting his hand on a dark-skinned person, caused controversy and accusation of racism. Hutchinson later responded and clarified by saying that Pagan Min is not a white person and that the other person depicted is not the game's protagonist. Hutchinson added that the reaction of the community regarding the cover art was "uncomfortable".
In addition to the standard version, a Limited Edition of the game is able to be purchased. This edition features additional in-game missions and an Impaler Harpoon Gun. The Limited Edition was a free upgrade for players who pre-ordered the game. A Kyrat Edition was also announced and it contains a collector's box, a poster, a journal, a map of Kyrat, a figurine of Pagan Min, and the missions from the Limited Edition. Players can also purchase a season pass for the game, which grants them access to additional content, including a new competitive multiplayer mode, a mission called "the Syringe", the missions from the Limited Edition, and the two other pieces of downloadable content. Far Cry 4: Arena Master, developed by Ludomade, was released alongside the game itself, as a companion app for the iOS and Android.
Far Cry 4 was released worldwide on November 18, 2014, for PlayStation 3, PlayStation 4, Windows, Xbox 360 and Xbox One. The PlayStation 4, Windows, and Xbox One versions feature higher visual fidelity, such as having a higher texture resolution and more animal fur. The game was supported by downloadable content upon launch. The first DLC, Escape From Durgesh Prison, featuring a new mission set during the main campaign, was released on January 13, 2015. It can be played solo or with another player. The Overrun DLC, which added new maps, a new vehicle, and a new mode to the game's competitive multiplayer, was released on February 10, 2015, for the consoles, and February 12, 2015, for PC. The Hurk Deluxe Pack was released on January 28, 2015, and added several story missions and weapons. The last downloadable content, Valley of the Yetis, features a new region and new story missions which can be played solo or co-operatively with another player. Valley of the Yetis was released on March 10, 2015, in North America and March 11, 2015, in Europe. The game was made available on Amazon Luna on November 23, 2020.
Reception
Far Cry 4 received "generally favorable" reviews, according to review aggregator Metacritic.
The game's story received mixed responses. Chris Carter from Destructoid praised the personality of Ajay Ghale, which is "less in-your-face" than that of Far Cry 3'''s protagonist Jason Brody. He also praised the villain, Pagan Min, who he considered took the spotlight every time he appeared in the game. Nick Tan, from Game Revolution, also praised Min's personality, but he complained that the character appeared too seldom in the game. Shacknews reviewer, Steven Wong, however, thought most characters are multilayered and interesting. As the examples he gives Pagan Min's chief interrogator, Pagan Min himself, and the main character's mother. Josh Harmon from Electronic Gaming Monthly thought that the characters in this game had more depth and that the choices made by players throughout the game were meaningful. Aoife Wilson from Eurogamer thought that the game's characters were memorable, but was disappointed by the story. JeuxVideo reviewer liked neither plot nor the characters, as they wrote: "If the main plot left us a little hungry [...], it is quite sad to note that our Nemesis Pagan also disappointed us" and "The key characters of this episode are unfortunately a little too caricatured and predictable". Edwin Evans-Thirlwell, writing for GamesRadar, thought that the story grew tiresome as players progressed, even though some of its characters were interesting. He further criticized the game's writing, which he thought was lackluster. Mike Splechta from GameZone praised the game's voice acting and applauded its storyline, calling it "much more satisfying".
The game's setting received positive responses. Carter thought that the vertical nature of the game's map created obstacles for players when they were traveling between places. However, he praised the interesting lore and wildlife found within the world, as well as the game's long draw distance. Harmon had similar comments, praising the game's graphics and Kyrat's culture. Harmon thought that the hilly landscape of the game's world gave players a sense of exploration, and hence made traversal enjoyable. Wilson thought, however, that the game's setting was not as compelling as the tropical setting of Far Cry 3. Furthermore, she thought that most of the time vast territories in Far Cry 4 are similar everywhere. Nevertheless, she praised the Shangri-la section, which, according to her, was one of the exceptions. She also notes that what the game "may lack in looks", "it makes up for by being positively stuffed with things to do". Matt Bertz from Game Informer praised the game's setting, which he thought was vibrant, varied and rich. Ludwig Kietzmann from Joystiq praised the content found within the world, and thought that the world itself was absorbing and interesting. ShackNews reviewer Steven Wong liked that as the player travels from southern to northern territories, the music and soldiers change from Indian to Chinese.
The game's design also received acclaim. Carter from Destructoid thought that the fortress and the outpost system provided players with a sense of accomplishment and success, and he considered having the freedom to use different ways to approach and complete missions one of the greatest parts of the game. In addition, Carter applauded the game's driving mechanics and the auto-drive feature, which he considered a significant improvement for the series. However he criticized the upgrade system, which he thought was directly converted from Far Cry 3 and was uninspiring. Electronic Gaming Monthly's Harmon thought that the introduction of the helicopter was dull. Mitch Dyer, from IGN, praised the game's economy system, which he thought was satisfying. He added that it gives players motivation to complete side-quests. GameSpot reviewer calls the game's economy "excellent" and enjoys the fact that it forces you to upgrade your wallet, so it can hold more money, and to craft a bigger backpack. Justin McElroy of Polygon praised the introduction of the grappling hook and the vertical map design, which he thought had allowed players to develop a strategy before taking action. He also praised the game for allowing players to use multiple approaches toward a single objective. GameSpots reviewer writes that after liberating an outpost and leaving it, the game may inform the player that it is already under another attack, when the player comes back to defend it and leaves again, he meets the same message that the outpost is under attack.
The game's multiplayer mode received a mixed response. Carter compared the competitive multiplayer to that of Tomb Raider, and called it "skippable". He considered the cooperative multiplayer a fun addition to the game but was disappointed by its limitations. He also added that the game would still be a strong title without these multiplayer elements. Bertz from Game Informer also found the multiplayer shallow and poorly-executed. He also criticized the lack of a large player pool and dedicated servers. Evans-Thirlwell of GamesRadar thought that the cooperative multiplayer was fun to play, but the asymmetrical competitive multiplayer was easy to forget. In contrast, GameZone Splechta thought that the competitive multiplayer mode was "a surprise" for him. Dyer echoed a similar statement, and he thought that it had successfully captured the scale and freedom offered by both the game's co-op and campaign. JeuxVideo wrote about multiplayer in the game: "You will understand that exploring Kyrat is honestly funny for two, assuming we are not likely to get tired in the long run".
Harmon thought that Far Cry 4 was an improvement over Far Cry 3, but he thought that the game felt and played too similarly to Far Cry 3, and he added that the game was unambitious. Bertz thought that Ubisoft Montreal's vision for Far Cry 4 is not as bold as its predecessors, and also thought that the experience delivered by Far Cry 4 did not stray far away from Far Cry 3. Tan also noted that the game's open world design felt not only similar to Far Cry 3, but also other Ubisoft franchises like Assassin's Creed and Watch Dogs. Evans-Thirlwell thought that the experience offered by Far Cry 4 was hollow as it had failed to innovate or reinvent its wheel. Dyer thought that the game was not ambitious, but the experience delivered was still gratifying and rewarding.
Sales
Ubisoft expected the game to sell at least six million copies in its first year of release. Far Cry 4 became the fastest-selling game and the most successful launch in the series in the first week of release. Far Cry 4 was the second best selling game in the United Kingdom for all-formats during the week of its release, only behind Grand Theft Auto V''. It was also the sixth best selling game in the US according to The NPD Group. As of December 31, 2014, the game has shipped seven million copies. The game sold more than 10 million copies during the eighth generation of video game consoles.
Awards
Notes
References
External links
Far Cry 4 at MobyGames
2014 video games
Asymmetrical multiplayer video games
Far Cry games
First-person shooters
Multiplayer and single-player video games
Open-world video games
PlayStation 3 games
PlayStation 4 games
Fiction about rebellions
Ubisoft games
Video game sequels
Video games developed in Canada
Video games scored by Cliff Martinez
Video games set in fictional countries
Video games set in mountains
Video games set in South Asia
Windows games
Xbox 360 games
Xbox One games
Video games using Havok
Works about the Nepalese Civil War
BAFTA winners (video games)
Red Storm Entertainment games
The Game Awards winners | Far Cry 4 | [
"Physics"
] | 7,266 | [
"Asymmetrical multiplayer video games",
"Symmetry",
"Asymmetry"
] |
41,337,731 | https://en.wikipedia.org/wiki/Howard%20Vollum%20Award | The Howard Vollum Award for Distinguished Accomplishment in Science and Technology is an annual award that was created by Reed College and endowed in 1975 by a grant from the Millicent Foundation, now a part of the M.J. Murdock Charitable Trust.
The award was created as a tribute to the late C. Howard Vollum, a 1936 Reed graduate and lifelong friend of the college. For his senior thesis project, Vollum built an oscilloscope; he later went on to co-found Tektronix, which revolutionized oscilloscope design and became a world leader in test, measurement, and monitoring technology. The award "recognizes and celebrates the exceptional achievement of one or more members of the scientific and technical community of the Northwest." Winners are selected for "the perseverance, creative imagination, ability to work with people, and fresh approach to problem solving that characterized Howard Vollum's career." Past recipients include Steve Jobs, Bill Gates, and Leroy Hood.
Recipients
2022 - Kevan M. Shokat
2018 - Mary Ruckelshaus
2017 - Geraldine (Geri) Richmond
2015 - Mary-Claire King
2014 - Ivan E. Sutherland
2013 - Kip S. Thorne
2012 - Edward D. Lazowska
2011 - Lynn M. Riddiford
2010 - Brian Druker
2009 - Carl E. Wieman
2008 - B. Kenneth Koe
2007 - Stanley Fields
2006 - Daniel Bump
2005 - Linus Torvalds
2004 - Warren M. Washington
2003 - Leroy Hood
2002 - Kenneth Raymond
2000 - James T. Russell
1999 - Jane Lubchenco
1997 - Russell J. Donnelly
1996 - Edwin G. Krebs
1995 - Adele Goldberg
1994 - Brian W. Matthews
1993 - Lynwood W. Swanson
1992 - Jerry F. Franklin
1991 - Steve Jobs
1990 - Lewis H. Kleinholz
1989 - Michael L. Posner
1988 - Harold K. Lonsdale
1987 - Gertrude F. Rempfer
1986 - David Powell Shoemaker
1985 - Howard S. Mason
1984 - Bill Gates and George Streisinger
1983 - Paul Lutus
1982 - Victor Klee
1981 - M. Lowell Edwards and Albert Starr
1980 - Paul H. Emmett
1979 - Linus C. Pauling
1978 - C. Norman Winningstad
1977 - Arthur F. Scott
1976 - John M. Fluke
1975 - Douglas C. Strain
References
American awards
Reed College
Awards established in 1975 | Howard Vollum Award | [
"Technology"
] | 488 | [
"Science and technology awards",
"Science award stubs"
] |
41,338,107 | https://en.wikipedia.org/wiki/List%20of%20recipients%20of%20the%20Pour%20le%20M%C3%A9rite%20for%20Sciences%20and%20Arts | This is a list of recipients of the Pour le Mérite for Sciences and Arts (), a German and formerly Prussian honor given since 1842 for achievement in the humanities, sciences, or arts.
Bibliography
References
External links
Science and technology award winners
Pour le Mérite for Sciences and Arts
Lists of German award winners | List of recipients of the Pour le Mérite for Sciences and Arts | [
"Technology"
] | 63 | [
"Science and technology awards",
"Science and technology award winners"
] |
57,550,988 | https://en.wikipedia.org/wiki/Source%20code%20editors%20for%20Erlang | Erlang is an open source programming language. Multiple development environments (including IDEs and source code editors with plug-ins adding IDE features) have support for Erlang.
Integrated Development Environments (IDEs)
Syntax, parsing, code-assist
Goto, searching
Code generation
Build, debug, run
References
Integrated development environments | Source code editors for Erlang | [
"Technology"
] | 69 | [
"Software comparisons",
"Computing comparisons"
] |
57,551,418 | https://en.wikipedia.org/wiki/Stepping%20feet%20illusion | The stepping feet illusion is a motion perception phenomenon involving two "buses," one blue and one yellow, moving horizontally across a "street" consisting of black and white stripes. Although both of the buses move at a constant speed, their perceived speed varies dramatically.
When the blue bus lies on the white stripes, the contrast is high (dark blue vs. white) and easily visible, so it appears to move faster than its actual speed. On the contrary, when the blue bus is against the black stripes, the contrast is low (dark blue vs. black) and harder to see, so the movement looks slower (see figs. 1 and 2). The opposite effects occur for the yellow bus. The two buses resemble a pair of moving of feet, giving the illusion its name.
Overall, the higher-contrast movements look faster than those with lower contrast. The effect disappears when the street's striped texture is removed because there is no contrast remaining, showing how an object's background can have a significant effect on its perceived speed.
Historical background
The stepping feet illusion was initially demonstrated by Stuart Anstis in 2003. He proposed that the contrast effect was experienced by drivers in foggy conditions in which the difference in brightness between the car and its surroundings is generally less than a sunny day. As a result, people tended to misjudge that the speed of their cars was moving slower than the actual speed and felt that other cars were becoming less visible. While in foggy conditions, other cars were reduced in contrast, thus appearing slower than they really were.
Causes
Contrast effect
Theoretically, the stepping feet illusion is influenced by the contrast between moving objects and their background. Contrast refers to the measured stimulus property of luminance differences. While the background has black and white stripes, the contrast changes from one line to the next. Both black and white lines have different patterns in contrast, for the dark object (blue bus), high contrast object against white lines and low contrast objects against black lines. In contrary for the light object (yellow bus), high contrast object against black lines and low contrast object against white lines. It is noted that not just any color can be paired for contrast, but there must be a luminance difference between the two, one of which must be bright, while the other must be dark.
Amplitude motion
Contrast not only modifies latency, but also the amplitude of perceived motion. Any difference in latency between different edges will move the diamond along the upright ellipse, but will not tilt the path from the vertical. Contrast modifies the perceived motion amplitudes of each side before edge motion coupled with boundary intersections.
Contrast effects not only real smooth movement, but also stroboscopic clear movement. A blue bus and a yellow bus placed one on top of another, surging back and forth horizontally over a quarter of the square. Around the dark, yellow bus appears to jump through more distances, because they have a higher contrast. Around the light or white stripes, the blue bus seems to leap through a further distance, because now the square had a higher contrast. Here, contrast affects the apparent amplitude of motion, not its speed.
Visual codes for motion coding
Anstis considers the stepping feet illusion as a motion analogue of the Bezold–Brücke color intensity effect on color vision. Bezold–Brucke illusions may show the same scheme for motion coding, i.e. reflecting non-linearity in which a cone in one cone, or more likely in one colored path, increase faster with its luminance than the other. The contrast illusion depicted in the illusion of footsteps may be just the analogue movement of the Bezold–Brucke effect, when two hypothetical neurons are tuned respectively for fast and slow motion. At low contrast, the speed of a particular medium simulates both channels equally.
If the contrast (not the luminance) increases, then both fast and slow channels will increase their firing rate, ideally by the same amount. In the model, however, non-linearity creeps in, and the advantages of fast channels increase with more contrast than slow channel acquisition. As a result, at high contrast, the same medium speed as before stimulates discharge channels disproportionately over slow channels and the movement looks more quickly subjectively.
Additional research
Jun On, Akiyasu Tomoeda, and Kokichi Sugihara (2014) won the best illusion of the year contest. They made a version of the "kickback illusion" which is closely related to the stepping feet illusion. In this illusion a rectangle moving at a constant speed in front of stripes generates apparent reverse motion, this apparent motion is similar to the action of a neck when the pigeon walks.
References
Optical illusions | Stepping feet illusion | [
"Physics"
] | 966 | [
"Optical phenomena",
"Physical phenomena",
"Optical illusions"
] |
57,551,451 | https://en.wikipedia.org/wiki/Thelymitra%20%C3%97%20mackibbinii | Thelymitra × mackibbinii, also known as Thelymitra mackibbinii and commonly known as the brilliant sun orchid, is a species of orchid that is endemic to Victoria. It has a single narrow, dark green leaf and one or two violet flowers with purplish tips and darker veins, and a yellow lobe on top of the anther.
Description
Thelymitra × mackibbinii is a tuberous, perennial herb with a single dark green, linear leaf long and wide. One or two violet-coloured flowers with purplish tips and darker veins wide are arranged on a flowering stem tall. The sepals and petals are long and wide. The column is deep violet, long and about wide. The lobe on the top of the anther is small, bright yellow and warty. The side lobes are yellow and curve forwards with rough or hairy edges. Flowering occurs from September to October.
Taxonomy and naming
Thelymitra × mackibbinii was first formally described in 1881 by Ferdinand von Mueller and the description was published in the Australasian Chemist and Druggist from a specimen collected near Maryborough. The specific epithet (mackibbinii) honours "John M'Kibbon, Esq." who collected the type specimen. John McKibbon was a schoolteacher and orchidologist.
This orchid was previously known as a natural hybrid but is currently recognised as the species Thelymitra mackibbinii.
Distribution and habitat
The brilliant sun orchid grows in open forest and woodland in the goldfields region of Victoria, near Stawell, St Arnaud and Maryborough. There is a single doubtful record from Port Elliot in South Australia from 1896.
Conservation
Fewer than thirty plants of the brilliant sun orchid were known in 2003. The species was probably more common before exploration for gold exploration and mining. The main threats to the species at present are trampling caused by recreational vehicles and grazing by both native and invasive species. Thelymitra mackibbinii is listed as "vulnerable" under the Victorian Government Flora and Fauna Guarantee Act 1988 and as "endangered" in the Australian Government Environment Protection and Biodiversity Conservation Act 1999.
References
mackibbinii
Endemic orchids of Australia
Orchids of Victoria (state)
Plants described in 1881
Hybrid plants
Taxa named by Ferdinand von Mueller | Thelymitra × mackibbinii | [
"Biology"
] | 469 | [
"Hybrid plants",
"Plants",
"Hybrid organisms"
] |
57,551,456 | https://en.wikipedia.org/wiki/Cartesian%20genetic%20programming | Cartesian genetic programming is a form of genetic programming that uses a graph representation to encode computer programs. It grew from a method of evolving digital circuits developed by Julian F. Miller and Peter Thomson in 1997. The term ‘Cartesian genetic programming’ first appeared in 1999 and was proposed as a general form of genetic programming in 2000. It is called ‘Cartesian’ because it represents a program using a two-dimensional grid of nodes.
Miller's keynote explains how CGP works. He edited a book entitled Cartesian Genetic Programming, published in 2011 by Springer.
The open source project dCGP implements a differentiable version of CGP developed at the European Space Agency by Dario Izzo, Francesco Biscani and Alessio Mereta able to approach symbolic regression tasks, to find solution to differential equations, find prime integrals of dynamical systems, represent variable topology artificial neural networks and more.
See also
Genetic programming
Gene expression programming
Grammatical evolution
Linear genetic programming
Multi expression programming
References | Cartesian genetic programming | [
"Biology"
] | 199 | [
"Genetics techniques",
"Genetic programming"
] |
57,551,585 | https://en.wikipedia.org/wiki/Pyxis%20Corporation | Pyxis Corporation was a San Diego company co-founded by Ronald R. Taylor and investor Tim Wollaeger in 1987. The company is the first to develop MedStation products in 1990 and is also a market leader for automated medication management, developing an automated dispensing cabinet under the name Pyxis.
History
Pyxis went public in 1992. The company continued to grow, eventually reaching 1,500 employees, and in 1996, it was bought by Cardinal Health for $867 million in stock.
In 2009 Cardinal Health completed the spin-off of its clinical and medical products businesses based in the previous Pyxis Corporation products into an independent medical technology company named Carefusion, with David Schlotterbeck as CEO. Carefusion continued the development of Pyxis systems.
In October 2014, Becton Dickinson bought Carefusion for a price of $12.2 billion in cash and stock. Since then, BD has been the developer of Carefusion and its Pyxis Systems.
Automated dispensing cabinet
The company created an automated dispensing cabinet called MedStation, a system of inventoried and connected cabinets and pharmacy units, allowing a safe delivery and reception from point to point between pharmacies to pharmacies, pharmacies to medication units and medication units to pharmacies. Pyxis products allowed healthcare personnel to avoid the manual recording of drugs dispensed or used by nurses and pharmacies based in a computerized and interconnected infrastructure, and allowed for the development of decentralized medication storages.
See also
List of unicorn startup companies
References
Pharmacies of the United States
Automation organizations
Medical technology companies of the United States
Companies established in 1987
Companies disestablished in 1996 | Pyxis Corporation | [
"Engineering"
] | 353 | [
"Automation organizations",
"Automation"
] |
57,552,007 | https://en.wikipedia.org/wiki/Fostriecin | Fostriecin is a type I polyketide synthase (PKS) derived natural product, originally isolated from the soil bacterium Streptomyces pulveraceus. It belongs to a class of natural products which characteristically contain a phosphate ester, an α,β-unsaturated lactam and a conjugated linear diene or triene chain produced by Streptomyces. This class includes structurally related compounds cytostatin and phoslactomycin. Fostriecin is a known potent and selective inhibitor of protein serine/threonine phosphatases, as well as DNA topoisomerase II. Due to its activity against protein phosphatases PP2A and PP4 (IC50 1.5nM and 3.0nM, respectively) which play a vital role in cell growth, cell division, and signal transduction, fostriecin was looked into for its antitumor activity in vivo and showed in vitro activity against leukemia, lung cancer, breast cancer, and ovarian cancer. This activity is thought to be due to PP2A's assumed role in regulating apoptosis of cells by activating cytotoxic T-lymphocytes and natural killer cells involved in tumor surveillance, along with human immunodeficiency virus-1 (HIV-1) transcription and replication.
Biosynthesis
The gene cluster for fostriecin consists of 21 open reading frames (ORFs) that encode for six modular type I polyketide synthases and seven tailoring enzymes. These enzymes within the fos gene have the nomenclature FosA-FosM, though not all are used in the biosynthesis of the target molecule. The six modular PKSs encoded in FosA-FosF give rise to a loading module, eight elongation modules, and a thioesterase domain.
Conventional polyketide synthase pathway
The loading module starts out the biosynthetic pathway by tethering to an acyl group of the acyl carrier protein (ACP).This starter unit then gets carried to module 1 where a malonyl group gets added on by malonyl-CoA followed by the β-carbonyl getting reduced to a hydroxyl group by a ketoreductase (KR) enzyme that then undergoes dehydration to a trans double bond by a dehydratase enzyme (DH). In this first module, there is an enoyl reductase enzyme (ER), but it is inactive. This chain then goes through two more elongations in module 2 and module 3 which are similar to module 1, only they result in cis double bonds at their respective β-carbons. The now 8-carbon chain then goes through another extension by malonyl-CoA in module 4, followed by a reduction by a KR domain. In module 5, an elongation is performed by methylmalonyl-CoA in which the chain undergoes another reduction to a hydroxyl group. The polyketide intermediate is then passed on to module 6 where another malonyl-CoA is loaded, and here, a reduction, then dehydration of the β-carbon form the final double bond of the linear chain. The growing chain is almost completely synthesized at this point and is taken through two elongations of 2 carbons in modules 7 and 8, each of which contain KRs to produce the final two hydroxyl groups in the alkyl chain. The linear carbon chain is now fully synthesized and hydrolyzed off of ACP by a thioesterase domain (TE) to undergo post-synthetic tailoring steps.
Post-synthetic tailoring
The post-synthetic tailoring enzymes for the production of fostriecin add on the four functionalities not originally included in the PKS pathway of the linear molecule. These enzymes include two cytochrome P450 enzymes (FosJ and FosK), one homoserine kinase (FosH), and one NAD-dependent epimerase/dehydratase family protein (FosM). The first step after the thioesterase domain, which forms a six-membered lactone ring, is the oxidation at C8 by FosJ, followed by a phosphorylation at C9 by FosH. This is then followed by an oxidation at the terminal carbon by FosK, and finally, a loss of malonic acid by FosM yields the desired natural product.
References
Polyketides
Phospholipids | Fostriecin | [
"Chemistry"
] | 960 | [
"Biomolecules by chemical classification",
"Phospholipids",
"Natural products",
"Signal transduction",
"Polyketides"
] |
57,552,333 | https://en.wikipedia.org/wiki/Health%20effects%20of%20Bisphenol%20A | Bisphenol A controversy centers on concerns and debates about the biomedical significance of bisphenol A (BPA), which is a precursor to polymers that are used in some consumer products, including some food containers. The concerns began with the hypothesis that BPA is an endocrine disruptor, i.e. it mimics endocrine hormones and thus has the unintended and possibly far-reaching effects on people in physical contact with the chemical.
Since 2008, several governments have investigated its safety, which prompted some retailers to withdraw polycarbonate products. The U.S. Food and Drug Administration (FDA) ended its authorization of the use of BPA in baby bottles and infant formula packaging, based on market abandonment, not safety. The European Union and Canada have banned BPA use in baby bottles.
The U.S. FDA states "BPA is safe at the current levels occurring in foods" based on extensive research, including two more studies issued by the agency in early 2014. The European Food Safety Authority (EFSA) reviewed new scientific information on BPA in 2008, 2009, 2010, 2011 and 2015: EFSA's experts concluded on each occasion that they could not identify any new evidence which would lead them to revise their opinion that the known level of exposure to BPA is safe; however, the EFSA does recognize some uncertainties, and will continue to investigate them.
In February 2016, France announced that it intends to propose BPA as a REACH Regulation candidate substance of very high concern (SVHC). The European Chemicals Agency agreed to the proposal in June 2017.
Production
The BPA controversy has gained momentum because of the quantity of BPA produced by the chemical industry. World production capacity of BPA was 1 million tons in the 1980s, and more than 2.2 million tons in 2009. It is a high production volume chemical. In 2003, U.S. consumption was 856,000 tons, 72% of which used to make polycarbonate plastic and 21% going into epoxy resins. In the U.S., less than 5% of the BPA produced is used in food contact applications, but remains in the canned food industry and printing applications such as sales receipts. On 20 February 2018, Packaging Digest reported that "At least 90%" of food cans no longer contained BPA.
Occurrence
BPA is rarely encountered in industrial products: it is invariably bound in a polymeric structure. Concerns therefore about exposure focus on the degradation, mainly by hydrolysis, of these polymers and the plastic objects derived therefrom.
Polycarbonate plastic, which is formed from BPA, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillings sealants, CDs and DVDs, household electronics, eyeglass lenses, foundry castings, and the lining of water pipes.
BPA is also used in the synthesis of polysulfones and polyether ketones, as an antioxidant in some plasticizers, and as a polymerization inhibitor in PVC. Epoxy resins derived from bisphenol A are used as coatings on the inside of almost all food and beverage cans; however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film.
Bisphenol A is a preferred color developer in carbonless copy paper and thermal point of sale receipt paper. When used in thermal paper, BPA is present as "free" (i.e., discrete, non-polymerized) BPA, which is likely to be more available for exposure than BPA polymerized into a resin or plastic. Upon handling, BPA in thermal paper can be transferred to skin, and there is some concern that residues on hands could be ingested through incidental hand-to-mouth contact. Furthermore, some studies suggest that dermal absorption may contribute some small fraction to the overall human exposure. European data indicate that the use of BPA in paper may also contribute to the presence of BPA in the stream of recycled paper and in landfills. Although there are no estimates for the amount of BPA used in thermal paper in the United States, in Western Europe, the volume of BPA reported to be used in thermal paper in 2005/2006 was 1,890 tonnes per year, while total production was estimated at 1,150,000 tonnes per year. (Figures taken from 2012 EPA draft paper.) Studies document potential spreading and accumulation of BPA in paper recycling, suggesting its presence for decades in paper recycling loop even after a hypothetical ban. Epoxy resin may or may not contain BPA, and is employed to bind gutta percha in some root canal procedures.
Biomedical history
In the early 1930s, the British biochemist Edward Charles Dodds tested BPA as an artificial estrogen, but found it to be 37,000 times less effective than estradiol. Dodds eventually developed a structurally similar compound, diethylstilbestrol (DES), which was used as a synthetic estrogen drug in women and animals until it was banned due to its risk of causing cancer; the ban on use of DES in humans came in 1971 and in animals, in 1979. BPA was never used as a drug. BPA's ability to mimic the effects of natural estrogen derives from the similarity of phenol groups on both BPA and estradiol, which enable this synthetic molecule to trigger estrogenic pathways in the body. Typically phenol-containing molecules similar to BPA are known to exert weak estrogenic activities, thus it is also considered an endocrine disruptor (ED) and estrogenic chemical. Xenoestrogens is another category the chemical BPA fits under because of its capability to interrupt the network that regulates the signals which control the reproductive development in humans and animals.
In 1997, adverse effects of low-dose BPA exposure in laboratory animals were first proposed. Modern studies began finding possible connections to health issues caused by exposure to BPA during pregnancy and during development. See Public health regulatory history in the United States and Chemical manufacturers' reactions to bans. As of 2014, research and debates are ongoing as to whether BPA should be banned or not.
A 2007 study investigated the interaction between bisphenol A's and estrogen-related receptor γ (ERR-γ). This orphan receptor (endogenous ligand unknown) behaves as a constitutive activator of transcription. BPA seems to bind strongly to ERR-γ (dissociation constant = 5.5 nM), but only weakly to the ER. BPA binding to ERR-γ preserves its basal constitutive activity. It can also protect it from deactivation from the SERM 4-hydroxytamoxifen (afimoxifene). This may be the mechanism by which BPA acts as a xenoestrogen. Different expression of ERR-γ in different parts of the body may account for variations in bisphenol A effects. For instance, ERR-γ has been found in high concentration in the placenta, explaining reports of high bisphenol accumulation in this tissue. BPA has also been found to act as an agonist of the GPER (GPR30).
Safety
Health effects
In 2017 the European Chemicals Agency concluded that BPA should be listed as a substance of very high concern due to its properties as an endocrine disruptor. In 2023, the European Food Safety Authority re-evaluated the safety of BFA and significantly reduced tolerable daily intake (TDI) to 0.2 nanograms (0.2 billionths of a gram), 20,000 times lower than the previous TDI. The European Food Safety Authority concluded that consumers with both average and high exposure to BPA in all age groups exceeded the new TDI, indicating health concerns.
In 2012, the United States' Food and Drug Administration (FDA) banned the use of BPA in baby bottles intended for children under 12 months. The Natural Resources Defense Council called the move inadequate, saying the FDA needed to ban BPA from all food packaging. The FDA maintains that the agency continues to support the safety of BPA for use in products that hold food.
In 2011, Andrew Wadge, the chief scientist of the United Kingdom's Food Standards Agency, commented on a 2011 U.S. study on dietary exposure of adult humans to BPA, saying, "This corroborates other independent studies and adds to the evidence that BPA is rapidly absorbed, detoxified, and eliminated from humans – therefore is not a health concern."
The Endocrine Society said in 2015 that the results of ongoing laboratory research gave grounds for concern about the potential hazards of endocrine-disrupting chemicals – including BPA – in the environment, and that on the basis of the precautionary principle these substances should continue to be assessed and tightly regulated. A 2016 review of the literature said that the potential harms caused by BPA were a topic of scientific debate and that further investigation was a priority because of the association between BPA exposure and adverse human health effects including reproductive and developmental effects and metabolic disease.
United States expert panel conclusions
In 2007, the U.S. federal government invited experts to Chapel Hill, North Carolina to perform a scientific assessment of literature on BPA. Thirty-eight experts in fields involved with bisphenol A gathered in Chapel Hill, North Carolina to review several hundred studies on BPA, many conducted by members of the group. At the end of the meeting, the group issued the Chapel Hill Consensus Statement, which stated "BPA at concentrations found in the human body is associated with organizational changes in the prostate, breast, testis, mammary glands, body size, brain structure and chemistry, and behavior of laboratory animals." The Chapel Hill Consensus Statement stated that average BPA levels in people were above those that cause harm to many animals in laboratory experiments. It noted that while BPA is not persistent in the environment or in humans, biomonitoring surveys indicate that exposure is continuous. This is problematic because acute animal exposure studies are used to estimate daily human exposure to BPA, and no studies that had examined BPA pharmacokinetics in animal models had followed continuous low-level exposures. The authors added that measurement of BPA levels in serum and other body fluids suggests the possibilities that BPA intake is much higher than accounted for or that BPA can bioaccumulate in some conditions (such as pregnancy). Following the Chapel Hill Statement, the US National Toxicology Program – Center for the Evaluation of Risks to Human Reproduction (NTP – CERHR), sponsored another literature assessment. The report, released in 2008, noted that "the possibility that bisphenol A may alter human development cannot be dismissed". Despite this report, the US Food and Drug Administration (FDA) BPA Task Force (formed in April 2008), concluded that products containing BPA were safe. In 2009, the FDA Science Board Subcommittee on Bisphenol A, an external committee assigned to review the FDA's report "concluded that the FDA failed to conduct a rigorous or extensive exposure assessment", leading the US Environmental Protection Agency (EPA) to conduct their own assessment.
The United States Federal Interagency Working Group (FIW) included a goal to reduce BPA exposure in the 2 December 2010 release of their 2020 Healthy People national objectives for improving the health of all Americans.
Metabolic disease
Numerous animal studies have demonstrated an association between endocrine disrupting chemicals (including BPA) and obesity. However, the relationship between bisphenol A exposure and obesity in humans is unclear. Cohort studies have shown there has been an association of prenatal BPA exposure and increased body fat percentage at age 7 and increased BMI by age 9. Not all studies have shown a positive relationship between BPA exposure and obesity, further studies on the effects of BPA on metabolic diseases need to take diet into consideration to remove any influence it might have on the outcome. Proposed mechanisms for BPA exposure to increase the risk of obesity include BPA-induced thyroid dysfunction, activation of the PPAR-gamma receptor, and disruption of neural circuits that regulate feeding behavior. BPA works by imitating the natural hormone 17B-estradiol. In the past BPA has been considered a weak mimicker of estrogen but newer evidence indicates that it is a potent mimicker. When it binds to estrogen receptors it triggers alternative estrogenic effects that begin outside of the nucleus. This different path induced by BPA has been shown to alter glucose and lipid metabolism in animal studies.
There are different effects of BPA exposure during different stages of development. During adulthood, BPA exposure modifies insulin sensitivity and insulin release without affecting weight.
Thyroid function
A 2007 review concluded that bisphenol-A has been shown to bind to thyroid hormone receptor and perhaps has selective effects on its functions.
A 2009 review about environmental chemicals and thyroid function raised concerns about BPA effects on triiodothyronine and concluded that "available evidence suggests that governing agencies need to regulate the use of thyroid-disrupting chemicals, particularly as such uses relate exposures of pregnant women, neonates and small children to the agents".
A 2009 review summarized BPA adverse effects on thyroid hormone action.
A 2016 case control study found that there was a significant association between urinary BPA levels and increased TSH levels (Thyroid- stimulating hormone) in a group of adult women.
Neurological effects
Limited epidemiological evidence suggests that exposure to BPA in the uterus and during childhood is associated with poor behavioral outcomes in humans. Exposure may be associated with higher levels of anxiety, depression, hyperactivity, and aggression in children. A panel convened by the National Toxicology Program (NTP) of the U.S. National Institutes of Health determined that there was "some concern" about BPA's effects on fetal and infant brain development and behavior. In January 2010, based on the NTP report, the FDA expressed the same level of concern.
A 2007 literature review concluded that BPA, like other chemicals that mimic estrogen (xenoestrogens), should be considered as a player within the nervous system that can regulate or alter its functions through multiple pathways. A 2008 review of animal research found that low-dose BPA maternal exposure can cause long-term consequences for the neurobehavioral development in mice.
A 2009 review raised concerns about a BPA effect on the anteroventral periventricular nucleus.
Disruption of the dopaminergic system
A 2008 review of human participants has concluded that BPA mimics estrogenic activity and affects various dopaminergic processes to enhance mesolimbic dopamine activity resulting in hyperactivity, attention deficits, and a heightened sensitivity to drugs of abuse.
Cancer
According to the WHO's INFOSAN, carcinogenicity studies conducted under the U.S. National Toxicology Program have shown increases in leukemia and testicular interstitial cell tumors in male rats. However, according to the note, "these studies have not been considered as convincing evidence of a potential cancer risk because of the doubtful statistical significance of the small differences in incidences from controls."
A 2010 review concluded that bisphenol A may increase cancer risk.
Several studies show evidence that the formation of prostate cancer in men is directly proportional to BPA exposure. Male subject diagnosed with prostate cancer were found to have higher urine concentration of BPA as opposed to the concentrations found in the control group's. This correlation may be due to BPA's ability to induce cell proliferation of the prostate cancer cells.
Breast cancer
Higher susceptibility to breast cancer has been found in many studies of rodents and primates exposed to BPA. However, it is the impact BPA has on breast cancer development in humans is unclear, as it is difficult to quantify an individual's BPA exposure over their lifetime. BPA, which includes a phenolic structure, has shown an association with agonist and antagonistic endocrine receptors that facilitate endocrine disorders such as breast and prostate cancer. Other endocrine disorders include infertility, polycystic ovary syndrome, and precocious puberty.
More oxidative stress in breast cancer cells were found to be directly proportional to BPA exposure as per the findings in several in vitro studies. Additionally, work related exposure to BPA, and women who are postmenopausal have suggested an increase in breast cancer incidence.
Mechanism of action
BPA is an endocrine disruptor, meaning BPA has a similar structure to oestrogen (ligand) and can bind to the oestrogen receptor ERα and ERβ and activate it.
Oestrogen is hydrophobic and is able to diffuse through the plasma membrane and into the target cell. Oestradiol binding to the oestrogen receptor releases the heat shock protein from the ligand binding domain of the receptor causing dimerization. The nuclear localisation signal targets the ligand-receptor complex to the nucleus where it can bind oestrogen response elements within the promoter of target genes on DNA. Subsequently, various cofactors are recruited allowing transcription of genes including those involved in cell proliferation.
When BPA is exposed to high temperatures or changes in pH, the ester bond linking BPA monomers is hydrolysed. Free BPA then competes with oestrogen for ERα and ERβ binding sites. When BPA successfully binds the receptor, it interacts with ERE and increases expression of target genes like WNT-4 and RANKL; two key players in stem cell proliferation and carcinogenesis. BPA was also shown to inactivate p53 which prevents tumour formation as it triggers apoptosis.
Fertility
As of 2022, current evidence shows a possible positive correlation between BPA levels, lower sperm quality, decreased motility and an increase in sperm immaturity. There is tentative evidence to support the idea that BPA exposure has negative effects on human fertility. Few studies have investigated whether recurrent miscarriage is associated with BPA levels. Exposure to BPA does not appear to be linked with higher rates of endometrial hyperplasia. Exposure to BPA does not appear to be linked with higher rates of endometrial hyperplasia. A 2009 cohort study linked urinary BPA concentration of women undergoing IVF egg retrieval, with an inverse correlation to oocyte release. The study found that for each unit increase in day 3 FSH (IU/L), there was an average decrease of 9% in the number of oocytes retrieved. The positive correlations found in animal studies warrants the continued research of BPA for couple fecundity.
Ubiquitous in environment through consumer products such as reusable plastics, food and beverage container liners, baby bottles, water resistant clothing. It has been identified as an EDC and found in urine, blood, amniotic fluid, breast milk and cord blood. Comparing blood BPA and phthalate levels between fertile and infertile women between the ages of 20–40, using gas chromatographic-mass spectrometry to analyze the amount of BPA, phthalate and their metabolites in peripheral venous blood, showed significantly elevated serum BPA level in infertile women, as well as women with PCOS (polycystic ovarian syndrome) and women with endometriosis
BPA is shown to have transgenerational effect by targeting ovarian function by changes in the structural integrity of microtubules that constitute meiotic spindles. BPA contaminants pass through amniotic fluid can alter steroidogenesis in fetal development. This will result if oocyte maturation failure as well as fertility This in turn will result in transgenerational effect and affect the third generation of offspring
Sexual function
Higher BPA exposure has been associated with increased self-reporting of decreased male sexual function but few studies examining this relationship have been conducted.
Asthma
Studies in mice have found a link between BPA exposure and asthma; a 2010 study on mice has concluded that perinatal exposure to 10 μg/mL of BPA in drinking water enhances allergic sensitization and bronchial inflammation and responsiveness in an animal model of asthma. A study published in JAMA Pediatrics has found that prenatal exposure to BPA is also linked to lower lung capacity in some young children. This study had 398 mother-infant pairs and looked at their urine samples to detect concentrations of BPA. They study found that every 10-fold increase in BPA was tied to a 55% increase in the odds of wheezing. The higher the concentration of BPA during pregnancy were linked to decrease lung capacity in children under four years old but the link disappeared at age 5. Associate professor of pediatrics at the University of Maryland School of Medicine said, "Exposure during pregnancy, not after, appears to be the critical time for BPA, possibly because it's affecting important pathways that help the lung develop."
In 2013, research from scientists at the Columbia Center for Children's Environmental Health also found a link between the compound and an increased risk for asthma. The research team reported that children with higher levels of BPA at ages 3, 5 and 7 had increased odds of developing asthma when they were between the ages of 5 and 12. The children in this study had about the same concentration of BPA exposure as the average U.S. child. Dr. Kathleen Donohue, an instructor at Columbia University Medical Center said, "they saw an increased risk of asthma at fairly routine, low doses of BPA." Kim Harley, who studies environmental chemicals and children's health, commented in the Scientific American journal saying while the study does not show that BPA causes asthma or wheezing, "it's an important study because we don't know a lot right now about how BPA affects immune response and asthma...They measured BPA at different ages, measured asthma and wheeze at multiple points, and still found consistent associations."
Animal research
The first evidence of the estrogenicity of bisphenol A came from experiments on rats conducted in the 1930s, but it was not until 1997 that adverse effects of low-dose exposure on laboratory animals were first reported.
Bisphenol A is an endocrine disruptor that can mimic estrogen and has been shown to cause negative health effects in animal studies. Bisphenol A closely mimics the structure and function of the hormone estradiol by binding to and activating the same estrogen receptor as the natural hormone. Early developmental stages appear to be the period of greatest sensitivity to its effects,
A study from 2008 concluded that blood levels of bisphenol A in neonatal mice are the same whether it is injected or ingested.
The current U.S. human exposure limit set by the EPA is 50 μg/kg/day.
In a 2010 commentary a group of scientists criticized a study designed to test low dose BPA exposure published in "Toxicological Sciences" and a later editorial by the same journal, which claimed the rats used in the study were insensitive to estrogen and that had other problems like the use of BPA-containing polycabonate cages while the authors disagreed.
Different expression of ERR-γ in different parts of the body may account for variations in bisphenol A effects. For instance, ERR-γ has been found in high concentration in the placenta, explaining reports of high bisphenol accumulation in this tissue.
Environmental effects
In 2010, the U.S. Environmental Protection Agency reported that over one million pounds of BPA are released into the environment annually. BPA can be released into the environment by both pre-consumer and post-consumer leaching. Common routes of introduction from the pre-consumer perspective into the environment are directly from chemical plastics, coat and staining manufacturers, foundries who use BPA in casting sand, or transport of BPA and BPA-containing products . Post-consumer BPA waste comes from effluent discharge from municipal wastewater treatment plants, irrigation pipes used in agriculture, ocean-borne plastic trash, indirect leaching from plastic, paper, and metal waste in landfills, and paper or material recycling companies. Despite a rapid soil and water half-life of 4.5 days, and an air half-life of less than one day, BPA's ubiquity makes it an important pollutant. BPA has a low rate of evaporation from water and soil, which presents issues, despite its biodegradability and low concern for bio-accumulation. BPA has low volatility in the atmosphere and a low vapor pressure between 5.00 and 5.32 Pascals. BPA has a high water solubility of about 120 mg/L and most of its reactions in the environment are aqueous. An interesting fact is that BPA dust is flammable if ignited, but it has a minimal explosive concentration in air. Also, in aqueous solutions, BPA has shown absorption of wavelengths greater than 250 nm.
The ubiquitous nature of BPA makes the compound an important pollutant to study as it has been shown to interfere with nitrogen fixation at the roots of leguminous plants associated with the bacterial symbiont Sinorhizobium meliloti. A 2013 study also observed changes in plant health due to BPA exposure. The study exposed soybean seedlings to various concentrations of BPA and saw changes in root growth, nitrate production, ammonium production, and changes in the activities of nitrate reductase and nitrite reductase. At low doses of BPA, the growth of roots were improved, the amount of nitrate in roots increased, the amount of ammonium in roots decreased, and the nitrate and nitrite reductase activities remained unchanged. However, at considerably higher concentrations of BPA, the opposite effects were seen for all but an increase in nitrate concentration and a decrease in nitrite and nitrate reductase activities. Nitrogen is both a plant nutritional substance, but also the basis of growth and development in plants. Changing concentrations of BPA can be harmful to the ecology of an ecosystem, as well as to humans if the plants are produced to be consumed.
The amount of absorbed BPA on sediment was also seen to decrease with increases in temperature, as demonstrated by a study in 2006 with various plants from the XiangJiang River in Central-South China. In general, as temperature increases, the water solubility of a compound increases. Therefore, the amount of sorbate that enters the solid phase will lower at the equilibrium point. It was also observed that the adsorption process of BPA on sediment is exothermic, the molar formation enthalpy, ΔH°, was negative, the free energy ΔG°, was negative, and the molar entropy, ΔS°, was positive. This indicates that the adsorption of BPA is driven by enthalpy. The adsorption of BPA has also been observed to decrease with increasing pH.
A 2005 study conducted in the United States had found that 91–98% of BPA may be removed from water during treatment at municipal water treatment plants. A more detailed explanation of aqueous reactions of BPA can be observed in the Degradation of BPA section below. Nevertheless, a 2009 meta-analysis of BPA in the surface water system showed BPA present in surface water and sediment in the United States and Europe. According to Environment Canada in 2011, "BPA can currently be found in municipal wastewater. […]initial assessment shows that at low levels, bisphenol A can harm fish and organisms over time."
BPA affects growth, reproduction, and development in aquatic organisms. Among freshwater organisms, fish appear to be the most sensitive species. Evidence of endocrine-related effects in fish, aquatic invertebrates, amphibians, and reptiles has been reported at environmentally relevant exposure levels lower than those required for acute toxicity. There is a widespread variation in reported values for endocrine-related effects, but many fall in the range of 1μg/L to 1 mg/L.
A 2009 review of the biological impacts of plasticizers on wildlife published by the Royal Society with a focus on aquatic and terrestrial annelids, molluscs, crustaceans, insects, fish and amphibians concluded that BPA affects reproduction in all studied animal groups, impairs development in crustaceans and amphibians and induces genetic aberrations.
Vertebrates
BPA is known as an endocrine disruptor compound (EDC) and has major neurological effects on vertebrates. Depending on the vertebrate species studied, the documented effects of ingestion and exposure to BPA may differ. In species such as Zebrafish, BPA affects the lateral line which is crucial for sensory perception and may affect the expression of genes that are controlling heart and skeletal muscle metabolism, as well as insulin secretion control. Aquatic vertebrates are especially impacted by BPA in reproduction. In the broad- snouted caiman, Caiman latirostris, gender is normally determined by the temperature at which the egg is incubated at. A study was conducted where their eggs were exposed to BPA. The first set was exposed at about 1000 μg/egg and all of the offspring were female. When the eggs were exposed at a lower concentration at about 90 μg/egg, the offspring produced were males. These male offspring exhibited disrupted seminiferous tubules. In mice, maternal diet has been studied and found to have a major effect on the offspring that were exposed to BPA during certain developmental stages. There are no direct studies on humans, however, studies on the vertebrates suggest the potential harm it may have.
Reproductive effects
Bisphenol A (BPA) is an environmental contaminant that disrupts the ecosystem, with the most profound effects observed in vertebrates. BPA infiltrates the environment by running off of landfills so because of this, it is mostly found in water. Aquatic vertebrates are thus the most affected by this form of pollution. After the aquatic vertebrates inhale BPA through their gills or skin, they are mainly affected by BPA at the cellular level, affecting their estrogen levels. BPA binds to the estrogen receptors and has an antagonist effect, which means that it decreases the amount of estrogen produced. To regulate reproductive functions, Gonadotropin releasing hormone (GnRH) is released. This helps with maturation of the sex organs in both males and females. Another study found that Barbus sp., immature barbels, in a river with traces of BPA expressed intersex characteristics. They had gonads with oogonia, spermatogonia and spermatocytes. Researchers concluded that BPA did not induce but did contribute to these intersex morphological expressions. After being exposed to 1μg/L BPA, Salmo trutta, brown trout, had reduced sperm density and mobility. In Pimephales promelas, fathead minnows, there was a reduction of sperm production. Both species were also exposed to 2 μg/L and 5 μg/L of BPA and it resulted in delayed ovulation or no ovulation for the fish.
A study was conducted using adult female Gobiocypris rarus, a rare minnow. The fish were exposed to 5 μg/L, 15μg/L and 50 μg/L of BPA for 14 days and 35 days. The results showed the group exposed to the highest amount of BPA (50 μg/L) for 35 days showed suppressed effects on oocyte development. It also showed that all groups had a stimulatory effect on the hepatic vitellogenin transcription (VTG). VTG is an indicator that the vertebrate has become exposed to environmental estrogens. The groups exposed to a lower concentration of BPA (5 μg/L & 15μg/L) showed an increase in expressed ovarian steroidogenic genes. Meanwhile, the group exposed to a higher concentration of BPA (50 μg/L) showed a decrease in expressed ovarian steroidogenic genes.
Although aquatic vertebrates are most commonly affected by BPA exposure in natural settings, researchers often learn how BPA effects other vertebrates using experimental mice models. In a study conducted twenty years ago, there was an accidental BPA exposure. This resulted in an increase in chromosomally abnormal eggs. This led researchers to question what other effects this has on mammals. It showed that BPA leads to meiotic changes such as fertility and maturation of sex organs. Scientists started to realize that this type of exposure could lead to mutations and affect multiple generations. Because of this, "BPA free" products started to be made but to do this, BPS was being used. A study was conducted showing that exposure to BPS increased mutations before zygotic development showing that it is just as dangerous as BPA.
Behavioral effects
BPA has major effects on the behavior of vertebrates, especially in their sensory processing systems. In zebrafish BPA can disrupt the signaling in the endocrine system and affect auditory development and function. Similar to a human ear, the zebrafish have a sensory organ called the lateral line that detects different forms of vibration. The hair cells within the lateral line are very sensitive to the toxic effects of BPA and are most commonly killed from BPA; fish are able to regrow hair cells but BPA has decreased their ability to reproduce them as efficiently. Fish without a fully functioning lateral line have behavioral changes such as: higher risk of predation, lowered prey detection and possible reproduction abilities. Unlike fish, mammals have a threat to go deaf if exposed directly.
As well as an endocrine disruptor compound (EDC), BPA has been found to inhibit nerve conduction. In the sciatic nerve of a frog (Rana tigrina), BPA inhibits the fast-conducting compound action potential (CAP). Estrogen receptors found in the plasma membrane of the sciatic nerve are affected by the BPA and inhibit CAP. However, estrogen receptors are not the only reason for inhibition, BPA is able to inhibit nerve functions without affecting estrogen.
A study in mice shows that BPA as an EDC acts as an agonist/antagonist for behavioral effects. BPA caused a decrease in exploratory and spatial behaviors in male mice who were exposed in the developmental state. In order to expose the males, pregnant females were fed with BPA in food the mice were compared to males whose mothers were fed with a phytoestrogen-free CTL diet. Males with the BPA exposure in developmental stages were less likely to be territorial when the other male mice were present. BPA exposure changed the behavior of sex and species-dependent behavior. These conclusions are suggestions to support the idea that BPA can cause sexually selected traits. Furthermore, maternal diet and exposing the developmental mice to BPA, may cause harm and lead to sexually dimorphic responses.
Positions of national and international bodies
World Health Organization
In November 2009, the WHO announced to organize an expert consultation in 2010 to assess low-dose BPA exposure health effects, focusing on the nervous and behavioral system and exposure to young children. The 2010 WHO expert panel recommended no new regulations limiting or banning the use of bisphenol-A, stating that "initiation of public health measures would be premature."
United States
In 2013, the FDA posted on its web site: "Is BPA safe? Yes. Based on FDA's ongoing safety review of scientific evidence, the available information continues to support the safety of BPA for the approved uses in food containers and packaging. People are exposed to low levels of BPA because, like many packaging components, very small amounts of BPA may migrate from the food packaging into foods or beverages." FDA issued a statement on the basis of three previous reviews by a group of assembled Agency experts in 2014 in its "Final report for the review of literature and data on BPA" that said in part, "The results of these new toxicity data and studies do not affect the dose-effect level and the existing NOAEL (5 mg/kg bw/day; oral exposure)."
Australia and New Zealand
In 2009 the Australia and New Zealand Food Safety Authority (Food Standards Australia New Zealand) did not see any health risk with bisphenol A baby bottles if the manufacturer's instructions were followed, as levels of exposure were very low and would not pose a significant health risk. It added that "the move by overseas manufacturers to stop using BPA in baby bottles is a voluntary action and not the result of a specific action by regulators." In 2008 it had suggested the use of glass baby bottles if parents had concerns.
In 2012 the Australian Government introduced a voluntary phase out of BPA use in polycarbonate baby bottles.
Canada
In April 2008, Health Canada concluded that, while adverse health effects were not expected, the margin of safety was too small for formula-fed infants and proposed classifying the chemical as "'toxic' to human health and the environment." The Canadian Minister of Health announced Canada's intent to ban the import, sale, and advertisement of polycarbonate baby bottles containing bisphenol A due to safety concerns, and investigate ways to reduce BPA contamination of baby formula packaged in metal cans. Subsequent news reports from April 2008 showed many retailers removing polycarbonate drinking products from their shelves.
On 18 October 2008, Health Canada noted that "bisphenol A exposure to newborns and infants is below levels that cause effects" and that the "general public need not be concerned".
In 2010, Canada's department of the environment declared BPA to be a "toxic substance" and added it to schedule 1 of the Canadian Environmental Protection Act, 1999.
European Union
The 2008 European Union Risk Assessment Report on , published by the European Commission and European Food Safety Authority (EFSA), concluded that -based products, such as polycarbonate plastic and epoxy resins, are safe for consumers and the environment when used as intended. By October 2008, after the Lang Study was published, the EFSA issued a statement concluding that the study provided no grounds to revise the current Tolerable Daily Intake (TDI) level for BPA of bodyweight.
On 22 December 2009, the EU Environment ministers released a statement expressing concerns over recent studies showing adverse effects of exposure to endocrine disruptors.
In September 2010, the European Food Safety Authority (EFSA) concluded after a "comprehensive evaluation of recent toxicity data […] that no new study could be identified, which would call for a revision of the current TDI". The Panel noted that some studies conducted on developing animals have suggested BPA-related effects of possible toxicological relevance, in particular biochemical changes in brain, immune-modulatory effects and enhanced susceptibility to breast tumours but considered that those studies had several shortcomings so the relevance of these findings for human health could not be assessed.
On 25 November 2010, the European Union executive commission said it planned to ban the manufacturing by and ban the marketing and market placement of polycarbonate baby bottles containing the organic compound by , according to John Dalli, commissioner in charge of health and consumer policy. This was backed by a majority of EU governments. The ban was called an over-reaction by Richard Sharpe, of the Medical Research Council's Human Reproductive Sciences Unit, who said to be unaware of any convincing evidence justifying the measure and criticized it as being done on political, rather than scientific grounds.
In January 2011 use of in baby bottles was forbidden in all EU-countries.
After reviewing more recent research, in 2012 EFSA made a decision to re-evaluate the human risks associated with exposure to BPA. They completed a draft assessment of consumer exposure to BPA in July 2013 and at that time asked for public input from all stakeholders to assist in forming a final report, which is expected to be completed in 2014.
In January 2014, EFSA presented a second part of the draft opinion which discussed the human health risks posed by BPA. The draft opinion was accompanied by an eight-week public consultation and also included adverse effects on the liver and kidney as related to BPA. From this it was recommended that the current TDI to be revised. In January 2015 EFSA indicated that the TDI was reduced from 50 to 4 μg/kg body weight/day – a recommendation, as national legislatures make the laws.
The EU Commission issued a new regulation regarding the use of in thermal paper on 12 December 2016. According to this new regulation, thermal paper containing cannot be placed on the EU market after 2 January 2020. This regulation came into effect on 2 January 2017 but there is a transition period of three years.
On 12 January 2017, BPA was added to the candidate list of substances of very high concern (SVHC). Candidate SVHC listing is a first step towards restricting the importing and use of a chemical in the EU. If the European Chemical Agency assigns SVHC status, the presence of BPA in a product at a concentration above 0.1% must be disclosed to a purchaser (with different rules for consumer and business purchasers). In February 2016, France had announced that it intended to propose BPA as a candidate SVHC by 8 August 2016.
Denmark
In May 2009, the Danish parliament passed a resolution to ban the use of BPA in baby bottles, which had not been enacted by April 2010. In March 2010, a temporary ban was declared by the Health Minister.
Belgium
In March 2010, senator Philippe Mahoux proposed legislation to ban BPA in food contact plastics. In May 2011, senators Dominique Tilmans and Jacques Brotchi proposed legislation to ban BPA from thermal paper.
France
On 5 February 2010, the French Food Safety Agency (AFSSA) questioned the previous assessments of the health risks of BPA, especially in regard to behavioral effects observed in rat pups following exposure in utero and during the first months of life. In April 2010, the AFFSA suggested the adoption of better labels for food products containing BPA.
On 24 March 2010, the French Senate unanimously approved a proposition of law to ban BPA from baby bottles. The National Assembly (Lower House) approved the text on 23 June 2010, which has been applicable law since 2 July 2010. On 12 October 2011, the French National Assembly voted a law forbidding the use of Bisphenol A in products aimed at less than 3-year-old children for 2013, and 2014 for all food containers.
On 9 October 2012, the French Senate adopted unanimously the law proposition to suspend manufacture, import, export and marketing of all food containers that include bisphenol A for 2015. The ban of bisphenol A in 2013 for food products designed for children less than 3-years-old was maintained.
Germany
On 19 September 2008, the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) stated that there was no reason to change the current risk assessment for bisphenol A on the basis of the Lang Study.
In October 2009, the German environmental organization Bund für Umwelt und Naturschutz Deutschland requested a ban on BPA for children's products, especially pacifiers, and products that make contact with food. In response, some manufacturers voluntarily removed the problematic pacifiers from the market.
Netherlands
On 3 March 2016, the (NVWA) issued cautionary recommendations to the Minister of Health, Welfare, and Sport and the Secretary for Economic Affairs, on the public intake of BPA, especially for vulnerable groups such as women who are pregnant or breastfeeding, and those with developing immune systems such as children below the age of 10. This was done in response to recent published research, and conclusions reached by the European Food Safety Authority. It also called for the concentration of BPA in drinking water to be lowered below 0.2 μg/L, in line with the maximum tolerable intake they recommend.
Switzerland
In February 2009, the Swiss Federal Office for Public Health, based on reports of other health agencies, stated that the intake of bisphenol A from food represents no risk to the consumer, including newborns and infants. However, in the same statement, it advised for proper use of polycarbonate baby bottles and listed alternatives.
Sweden
By 26 May 1995, the Swedish Chemicals Agency asked for a BPA ban in baby bottles, but the Swedish Food Safety Authority prefers to await the expected European Food Safety Authority's updated review. The Minister of Environment said to wait for the EFSA review but not for too long.
From March 2011 it is prohibited to manufacture babybottles containing bisphenol A and from July 2011 they can not be bought in stores. On 12 April 2012, the Swedish government announced that Sweden will ban BPA in cans containing food for children under the age of three.
Since January 2, 2020, BPA has been banned in thermal receipts as a consequence of the EU wide ban.
Since September 1, 2016, it is prohibited to use BPA when relining water pipes with CIPP.
United Kingdom
In December 2009, responding to a letter from a group of seven scientists that urged the UK Government to "adopt a standpoint consistent with the approach taken by other Governments who have ended the use of BPA in food contact products marketed at children", the UK Food Standards Agency reaffirmed, in January 2009, its view that "exposure of UK consumers to BPA from all sources, including food contact materials, was well below levels considered harmful".
Turkey
As of 10 June 2011, Turkey banned the use of BPA in baby bottles and other PC items produced for babies.
Japan
Between 1998 and 2003, the canning industry voluntarily replaced its BPA-containing epoxy resin can liners with BPA-free polyethylene terephthalate (PET) in many of its products. For other products, it switched to a different epoxy lining that yielded much less migration of BPA into food than the previously used resin. In addition, polycarbonate tableware for school lunches was replaced by BPA-free plastics.
Human exposure sources
The major human exposure route to BPA is diet, including ingestion of contaminated food and water.
It is especially likely to leach from plastics when they are cleaned with harsh detergents or when they contain acidic or high-temperature liquids. BPA is used to form epoxy resin coating of water pipes; in older buildings, such resin coatings are used to avoid replacement of deteriorating pipes. In the workplace, while handling and manufacturing products which contain BPA, inhalation and dermal exposures are the most probable routes. There are many uses of BPA for which related potential exposures have not been fully assessed including digital media, electrical and electronic equipment, automobiles, sports safety equipment, electrical laminates for printed circuit boards, composites, paints, and adhesives. In addition to being present in many products that people use on a daily basis, BPA has the ability to bioaccumulate, especially in water bodies. In one review, it was seen that although BPA is biodegradable, it is still detected after wastewater treatment in many waterways at concentrations of approximately 1 ug/L. This study also looked at other pathways where BPA could potentially bioaccumulate and found "low-moderate potential...in microorganisms, algae, invertebrates, and fish in the environment" suggesting that some environmental exposures are less likely.
In November 2009, the Consumer Reports magazine published an analysis of BPA content in some canned foods and beverages, where in specific cases the content of a single can of food could exceed the FDA "Cumulative Exposure Daily Intake" limit.
The CDC had found bisphenol A in the urine of 95% of adults sampled in 1988–1994 and in 93% of children and adults tested in 2003–04. The USEPA Reference dose (RfD) for BPA is 50 μg/kg/day which is not enforceable but is the recommended safe level of exposure. The most sensitive animal studies show effects at much lower doses, and several studies of children, who tend to have the highest levels, have found levels over the EPA's suggested safe limit figure.
A 2009 Health Canada study found that the majority of canned soft drinks it tested had low, but measurable levels of bisphenol A. A study conducted by the University of Texas School of Public Health in 2010 found BPA in 63 of 105 samples of fresh and canned foods, including fresh turkey sold in plastic packaging and canned infant formula. A 2011 study published in Environmental Health Perspectives, "Food Packaging and Bisphenol A and Bis(2-Ethyhexyl) Phthalate Exposure: Findings from a Dietary Intervention," selected 20 participants based on their self-reported use of canned and packaged foods to study BPA. Participants ate their usual diets, followed by three days of consuming foods that were not canned or packaged. The study's findings include: 1) evidence of BPA in participants' urine decreased by 50% to 70% during the period of eating fresh foods; and 2) participants' reports of their food practices suggested that consumption of canned foods and beverages and restaurant meals were the most likely sources of exposure to BPA in their usual diets. The researchers note that, even beyond these 20 participants, BPA exposure is widespread, with detectable levels in urine samples in more than an estimated 90% of the U.S. population. Another U.S. study found that consumption of soda, school lunches, and meals prepared outside the home were statistically significantly associated with higher urinary BPA.
A 2011 experiment by researchers at the Harvard School of Public Health indicated that BPA used in the lining of food cans is absorbed by the food and then ingested by consumers. Of 75 participants, half ate a lunch of canned vegetable soup for five days, followed by five days of fresh soup, while the other half did the same experiment in reverse order. "The analysis revealed that when participants ate the canned soup, they experienced more than a 1,000 percent increase in their urinary concentrations of BPA, compared to when they dined on fresh soup."
A 2009 study found that drinking from polycarbonate bottles increased urinary bisphenol A levels by two-thirds, from 1.2 μg/g creatinine to 2 μg/g creatinine. Consumer groups recommend that people wishing to lower their exposure to bisphenol A avoid canned food and polycarbonate plastic containers (which shares resin identification code 7 with many other plastics) unless the packaging indicates the plastic is bisphenol A-free. To avoid the possibility of BPA leaching into food or drink, the National Toxicology Panel recommends avoiding microwaving food in plastic containers, putting plastics in the dishwasher, or using harsh detergents.
Besides diet, exposure can also occur through air and through skin absorption. Free BPA is found in high concentration in thermal paper and carbonless copy paper, which would be expected to be more available for exposure than BPA bound into resin or plastic. Popular uses of thermal paper include receipts, event and cinema tickets, labels, and airline tickets. A Swiss study found that 11 of 13 thermal printing papers contained (BPA). Upon dry finger contact with a thermal paper receipt, roughly BPA () was transferred to the forefinger and the middle finger. For wet or greasy fingers approximately more was transferred. Extraction of BPA from the fingers was possible up to after exposure. Further, it has been demonstrated that thermal receipts placed in contact with paper currency in a wallet for 24 hours cause a dramatic increase in the concentration of BPA in paper currency, making paper money a secondary source of exposure. Another study has identified BPA in all of the waste paper samples analysed (newspapers, magazines, office paper, etc.), indicating direct results of contamination through paper recycling. Free BPA can readily be transferred to skin, and residues on hands can be ingested. Bodily intake through dermal absorption (99% of which comes from handling receipts) has been shown for the general population to be 0.219 ng/kg bw/day (occupationally exposed persons absorb higher amounts at 16.3 ng/kg bw/day) whereas aggregate intake (food/beverage/environment) for adults is estimated at 0.36–0.43 μg/kg bw/day (estimated intake for occupationally exposed adults is 0.043–100 μg/kg bw/day).
A study from 2011 found that Americans of all age groups had twice as much BPA in their bodies as Canadians; the reasons for the disparity were unknown, as there was no evidence to suggest higher amounts of BPA in U.S. foods, or that consumer products available in the U.S. containing BPA were BPA-free in Canada. According to another study it may have been due to differences in how and when the surveys were done, because "although comparisons of measured concentrations can be made across populations, this must be done with caution owing to differences in sampling, in the analytical methods used and in the sensitivity of the assays."
Comparing data from the National Health and Nutrition Examination Surveys (NHANES) from four time periods between 2003 and 2012, urinary BPA data the median daily intake for the overall population is approximately 25 ng/kg/day and below current health based guidelines. Additionally, daily intake of BPA in the United States has decreased significantly compared to the intakes measured in 2003–2004. Public attention and governmental action during this time period may have decreased the exposure to BPA somewhat but these studies did not include children under the age of six. According to the Endocrine Society, age of exposure is an important factor in determining the extent to which endocrine disrupting chemicals will have an effect, and the effects on developing fetuses or infants is quite different than an adult.
Fetal and early-childhood exposures
A 2009 study found higher urinary concentrations in young children than in adults under typical exposure scenarios. In adults, BPA is eliminated from the body through a detoxification process in the liver. In infants and children, this pathway is not fully developed so they have a decreased ability to clear BPA from their systems. Several recent studies of children have found levels that exceed the EPAs suggested safe limit figure.
Infants fed with liquid formula are among the most exposed, and those fed formula from polycarbonate bottles can consume up to 13 micrograms of bisphenol A per kg of body weight per day (μg/kg/day; see table below). In the U.S. and Canada, BPA has been found in infant liquid formula in concentrations varying from 0.48 to 11 ng/g. BPA has been rarely found in infant powder formula (only 1 of 14). The U.S. Department of Health & Human Services (HHS) states that "the benefit of a stable source of good nutrition from infant formula and food outweighs the potential risk of BPA exposure". BPA is present in human breast milk, having been found by several studies in 62–75% of breast milk samples. This is presumably due to the mothers being exposed to BPA since it is not naturally produced by the body.
Children may be more susceptible to BPA exposure than adults (see health effects).
A 2010 study of people in Austria, Switzerland, and Germany has suggested polycarbonate (PC) baby bottles as the most prominent role of exposure for infants, and canned food for adults and teenagers. In the United States, the growing concern over BPA exposure in infants in recent years has led the manufacturers of plastic baby bottles to stop using BPA in their bottles. The FDA banned the use of BPA in baby bottles and sippy cups (July 2012) as well as the use of epoxy resins in infant formula packaging. However, babies may still be exposed if they are fed with old or hand-me-down bottles bought before the companies stopped using BPA.
One often overlooked source of exposure occurs when a pregnant woman is exposed, thereby exposing the fetus. Animal studies have shown that BPA can be found in both the placenta and the amniotic fluid of pregnant mice. Since BPA was also "detected in the urine and serum of pregnant women and the serum, plasma, and placenta of newborn infants" a study to examine the externalizing behaviors associated with prenatal exposure to BPA was performed which suggests that exposures earlier in development have more of an effect on the behavior outcomes and that female children (2-years-old) are impacted more than males. A study of 244 mothers indicated that exposure to BPA before birth could affect the behavior of girls at age 3. Girls whose mother's urine contained high levels of BPA during pregnancy scored worse on tests of anxiety and hyperactivity. Although these girls still scored within a normal range, for every 10-fold increase in the BPA of the mother, the girls scored at least six points lower on the tests. Boys did not seem to be affected by their mother's BPA levels during pregnancy. After the baby is born, maternal exposure can continue to affect the infant through transfer of BPA to the infant via breast milk. Because of these exposures that can occur both during and after pregnancy, mothers wishing to limit their child's exposure to BPA should attempt to limit their own exposures during that time period.
While the majority of exposures have been shown to come through the diet, accidental ingestion can also be considered a source of exposure. One study conducted in Japan tested plastic baby books to look for possible leaching into saliva when babies chew on them. While the results of this study have yet to be replicated, it gives reason to question whether exposure can also occur in infants through ingestion by chewing on certain books or toys.
Regulation
Public health regulatory history in the United States
Charles Schumer introduced a 'BPA-Free Kids Act of 2008' to the U.S. Senate seeking to ban BPA in any product designed for use by children and require the Center for Disease Control to conduct a study about the health effects of BPA exposure. It was reintroduced in 2009 in both Senate and House, but died in committee each time.
In 2008, the FDA reassured consumers that current limits were safe, but convened an outside panel of experts to review the issue. The Lang study was released, and co-author David Melzer presented the results of the study before the FDA panel. An editorial accompanying the Lang study's publication criticized the FDA's assessment of bisphenol A: "A fundamental problem is that the current ADI [acceptable daily intake] for BPA is based on experiments conducted in the early 1980s using outdated methods (only very high doses were tested) and insensitive assays. More recent findings from independent scientists were rejected by the FDA, apparently because those investigators did not follow the outdated testing guidelines for environmental chemicals, whereas studies using the outdated, insensitive assays (predominantly involving studies funded by the chemical industry) are given more weight in arriving at the conclusion that BPA is not harmful at current exposure levels." The FDA was criticized that it was "basing its conclusion on two studies while downplaying the results of hundreds of other studies." Diana Zuckerman, president of the National Research Center for Women and Families, criticized the FDA in her testimony at the FDA's public meeting on the draft assessment of bisphenol A for use in food contact applications, that "At the very least, the FDA should require a prominent warning on products made with BPA".
In March 2009 Suffolk County, New York became the first county to pass legislation to ban baby beverage containers made with bisphenol A. By March 2009, legislation to ban bisphenol A had been proposed in both House and Senate.
In the same month, Rochelle Tyl, author of two studies used by FDA to assert BPA safety in August 2008, said those studies did not claim that BPA is safe, because they were not designed to cover all aspects of the chemical's effects. In May 2009, Minnesota and Chicago were the first U.S. jurisdictions to pass regulations limiting or banning BPA. In June 2009, the FDA announced its decision to reconsider the BPA safety levels. Grassroots political action led Connecticut to become the first U.S. state to ban bisphenol A not only from infant formula and baby food containers, but also from any reusable food or beverage container. In July 2009, the California Environmental Protection Agency's Developmental and Reproductive Toxicity Identification Committee in the California Office of Environmental Health Hazard Assessment unanimously voted against placing Bisphenol A on the state's list of chemicals that are believed to cause reproductive harm. The panel was concerned over the growing scientific evidence showing BPA's reproductive harm in animals, found that there was insufficient data of the effects in humans. Critics pointed out that the same panel failed to add second-hand smoke to the list until 2006, and only one chemical was added to the list in the last three years. In September, the U.S. Environmental Protection Agency announced that it was evaluating BPA for an action plan development. In October, the NIH announced $30,000,000 in stimulus grants to study the health effects of BPA. This money was supposed to result in many peer-reviewed publications.
On 15 January 2010, the FDA expressed "some concern", the middle level in its scale of concerns, about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants, and young children, and announced that it was taking reasonable steps to reduce human exposure to BPA in the food supply. However, the FDA was not recommending that families change the use of infant formula or foods, as it saw the benefit of a stable source of good nutrition as outweighing the potential risk from BPA exposure. On the same date, the Department of Health and Human Services released information to help parents to reduce children's BPA exposure. As of 2010 many U.S. states were considering some sort of BPA ban.
In June 2010 the 2008–2009 Annual Report of the President's Cancer Panel was released and recommended: "Because of the long latency period of many cancers, the available evidence argues for a precautionary approach to these diverse chemicals, which include (…) bisphenol A". In August 2010, the Maine Board of Environmental Protection voted unanimously to ban the sale of baby bottles and other reusable food and beverage containers made with bisphenol A as of January 2012. In February 2011, the newly elected governor of Maine, Paul LePage, gained national attention when he spoke on a local TV news show saying he hoped to repeal the ban because, "There hasn't been any science that identifies that there is a problem" and added: "The only thing that I've heard is if you take a plastic bottle and put it in the microwave and you heat it up, it gives off a chemical similar to estrogen. So the worst case is some women may have little beards." In April 2011, the Maine legislature passed a bill to ban the use of BPA in baby bottles, sippy cups, and other reusable food and beverage containers, effective 1 January 2012. Governor LePage refused to sign the bill.
In October 2011, California banned BPA from baby bottles and toddlers' drinking cups, effective 1 July 2013. By 2011, 26 states had proposed legislation that would ban certain uses of BPA. Many bills died in committee. In July 2011, the American Medical Association (AMA) declared feeding products for babies and infants that contain BPA should be banned. It recommended better federal oversight of BPA and clear labeling of products containing it. It stressed the importance of the FDA to "actively incorporate current science into the regulation of food and beverage BPA-containing products."
In 2012, the FDA concluded an assessment of scientific research on the effects of BPA and stated in the March 2012 Consumer Update that "the scientific evidence at this time does not suggest that the very low levels of human exposure to BPA through the diet are unsafe" although recognizing "potential uncertainties in the overall interpretation of these studies including route of exposure used in the studies and the relevance of animal models to human health. The FDA is continuing to pursue additional research to resolve these uncertainties." Yet on 17 July 2012, the FDA banned BPA from baby bottles and sippy cups. A FDA spokesman said the agency's action was not based on safety concerns and that "the agency continues to support the safety of BPA for use in products that hold food." Since manufacturers had already stopped using the chemical in baby bottles and sippy cups, the decision was a response to a request by the American Chemistry Council, the chemical industry's main trade association, who believed that a ban would boost consumer confidence. The ban was criticized as "purely cosmetic" by the Environmental Working Group, which stated that "If the agency truly wants to prevent people from being exposed to this toxic chemical associated with a variety of serious and chronic conditions it should ban its use in cans of infant formula, food and beverages." The Natural Resources Defense Council called the move inadequate saying, the FDA needs to ban BPA from all food packaging.
As of 2014, 12 states have banned BPA from children's bottles and feeding containers.
Environmental regulation in the United States
On 30 December 2009 EPA released a so-called action plan for four chemicals, including BPA, which would have added it to the list of "chemicals of concern" regulated under the Toxic Substances Control Act. In February 2010, after lobbyists for the chemical industry had met with administration officials, the EPA delayed BPA regulation by not including the chemical.
On 29 March 2010, EPA published a revised action plan for BPA as "chemical of concern". In October 2010 an advanced Notice of Proposed Rulemaking for BPA testing was published in the Federal Register July 2011. After more than 3 years at the Office of Information and Regulatory Affairs (OIRA), part of the Office of Management and Budget (OMB), which has to review draft proposals within 3 months, OIRA had not done so.
In September 2013 EPA withdrew its 2010 draft BPA rule. saying the rule was "no longer necessary", because EPA was taking a different track at looking at chemicals, a so-called "Work Plan" of more than 80 chemicals for risk assessment and risk reduction. Another proposed rule that EPA withdrew would have limited industry's claims of confidential business information (CBI) for the health and safety studies needed, when new chemicals are submitted under TSCA for review. The EPA said it continued "to try to reduce unwarranted claims of confidentiality and has taken a number of significant steps that have had dramatic results... tightening policies for CBI claims and declassifying unwarranted confidentiality claims, challenging companies to review existing CBI claims to ensure that they are still valid and providing easier and enhanced access to a wider array of information."
The chemical industry group American Chemistry Council commended EPA for "choosing a course of action that will ultimately strengthen the performance of the nation's primary chemical management law." Richard Denison, senior scientist with the Environmental Defense Fund, commented "both rules were subject to intense opposition and lobbying from the chemical industry" and "Faced presumably with the reality that [the Office of Information and Regulatory Affairs] was never going to let EPA even propose the rules for public comment, EPA decided to withdraw them."
On 29 January 2014 EPA released a final alternatives assessment for BPA in thermal paper as part of its Design for the Environment program.
Chemical manufacturers reactions to bans
In March 2009 the six largest U.S. producers of baby bottles decided to stop using bisphenol A in their products. The same month Sunoco, a producer of gasoline and chemicals, refused to sell BPA to companies for use in food and water containers for children younger than 3, saying it could not be certain of the compound's safety.
In May 2009, Lyndsey Layton from the Washington Post accused manufacturers of food and beverage containers and some of their biggest customers of the public relations and lobbying strategy to block government BPA bans. She noted that, "Despite more than 100 published studies by government scientists and university laboratories that have raised health concerns about the chemical, the Food and Drug Administration has deemed it safe largely because of two studies, both funded by a chemical industry trade group". In August 2009 the Milwaukee Journal Sentinel investigative series into BPA and its effects showed the Society of the Plastics Industry plans of a major public relations blitz to promote BPA, including plans to attack and discredit those who report or comment negatively on BPA and its effects.
BPA free, unknown substitute
The chemical industry over time responded to criticism of BPA by promoting "BPA-free" products. For example, in 2010, General Mills announced it had found a "BPA-free alternative" can liner that works with tomatoes. It said it would begin using the BPA-free alternative in tomato products sold by its organic foods subsidiary Muir Glen with that year's tomato harvest. As of 2014, General Mills has refused to state which alternative chemical it uses, and whether it uses it on any of its other canned products.
BPA free, epoxyfree
A minority of companies have stated what alternative compound(s) they use. Following an inquiry by Representative Edward Markey (D-Mass) seventeen companies replied saying they were going BPA-free, including Campbell Soup Company and General Mills Inc. None of the companies said they are or were going to use Bisphenol S; only four stated the alternative to BPA that they will be using. ConAgra stated in 2013 "alternate liners for tomatoes are vinyl...New aerosol cans are lined with polyester resin". Eden Foods stated that only their "beans are canned with a liner of an oleoresinous c-enamel that does not contain the endocrine disruptor BPA. Oleoresin is a mixture of oil and resin extracted from plants such as pine or balsam fir". Hain Celestial Group will use "modified polyester and/ or acrylic … by June 2014 for our canned soups, beans, and vegetables". Heinz stated in 2011 it "intend[s] to replace epoxy linings in all our food containers…. We have prioritized baby foods", and in 2012 "no BPA in any plastic containers we use".
BPA substitute BPS
Some "BPA free" plastics are made from epoxy containing a compound called bisphenol S (BPS). BPS shares a similar structure and versatility to BPA and has been used in numerous products from currency to thermal receipt paper. Widespread human exposure to BPS was confirmed in an analysis of urine samples taken in the U.S., Japan, China, and five other Asian countries. Researchers found BPS in all the receipt paper, 87 percent of the paper currency and 52 percent of recycled paper they tested. The study found that people may be absorbing 19 times more BPS through their skin than the amount of BPA they absorbed, when it was more widely used.
In a 2011 study researchers looked at 455 common plastic products and found that 70% tested positive for estrogenic activity. After the products had been washed or microwaved the proportion rose to 95%. The study concluded: "Almost all commercially available plastic products we sampled, independent of the type of resin, product, or retail source, leached chemicals having reliably-detectable EA [endocrine activity], including those advertised as BPA-free. In some cases, BPA-free products released chemicals having more EA than BPA-containing products." A systematic review published in 2015 found that "based on the current literature, BPS and BPF are as hormonally active as BPA, and have endocrine disrupting effects."
Phenol-based substitutes
Among potential substitutes for BPA, phenol-based chemicals closely related to BPA have been identified. The non-extensive list includes bisphenol E (BPE), bisphenols B (BPB), 4-cumylphenol (HPP) and bisphenol F (BPF), with only BPS being currently used as main substitute in thermal paper.
Degradation of BPA
Microbial degradation
The enzyme 4-hydroxyacetophenone monooxygenase, which can be found in Pseudomonas fluorescens, uses (4-hydroxyphenyl)ethan-1-one, NADPH, H+ and O2 to produce 4-hydroxyphenyl acetate, NADP+, and H2O.
The fungus Cunninghamella elegans is also able to degrade synthetic phenolic compounds like bisphenol A.
Plant degradation
Portulaca oleracea efficiently removes bisphenol A from a hydroponic solution. How this happens is unclear.
Photodegradation
Photodegradation is BPA's main method of natural weathering in the environment, via the Photo Fries rearrangement. Experimentally, BPA has been shown to photodegrade in reactions catalyzed by zinc oxide, titanium dioxide, and tin dioxide, as methods of water decontamination procedures. The Photo Fries degradation is a complex rearrangement of the aromatic carbonate backbone of BPA into phenyl salicylate and dihydroxybenzophenone derivatives before the energized ring releases carbon dioxide. In aqueous solution, BPA shows UV absorption of wavelengths between 250 nm and 360 nm, and the Photo Fries degradation occurs at wavelengths less than 300 nm. The reaction begins by an alpha cleavage between the carbonyl carbon and the oxygen in the carbonate linkage, with the subsequent Photo Fries rearrangement of the products. Seen is the mechanism of the photodegradation of BPA by the Photo Fries reaction:
Combustion of BPA
Hydroxyl radicals are powerful oxidants that transform BPA into different forms of phenolic group compounds. The advanced photocatalytic oxidation of BPA, using compounds like sodium hypochlorite, NaOCl, as the oxidizing agent, can accelerate the degradation efficiency by releasing oxygen into the water. This decomposition occurs when BPA is exposed to UV irradiation. This release of oxygen, another strong oxidant, also causes BPA disintegration in aqueous conditions to produce carbon dioxide and water. The dissolved carbon dioxide in the water results in an increase of carbonic acid, therefore causing an acidification of the water.
Oxidation of BPA by ozone
During water treatment, BPA can be removed through ozonation. A 2008 study has identified the degradation products of this reaction, through the use of liquid chromatography and mass spectrometry. The reaction of BPA and ozone is seen below:
Solutions of BPA and water decreased in pH after the ozonation process was completed. pH drops from 6.5 to 4.5 pH units were observed. This is likely because of the formation of carboxylic acids. These products were produced when the solution was 20±2 °C. The products have high molecular weight. Also, ozone is electrophilic, so reactions were between ozone and aromatic rings by electrophilic substitution.
Kinetics of BPA degradation
In 1991, the first explanation of the rate of BPA degradation through ozonation was determined.
This relates the concentration of BPA to time by the apparent dissociation constant, concentration of BPA, and the concentration of ozone.
References
Further reading
External links
International Chemical Safety Cards – Bisphenol A NIOSH, partly updated in October 2005. Retrieved 8 April 2015
Bisphenol A (BPA) in food FDA, November 2014. Retrieved 8 April 2015
BPA Data Gap Analysis FDA, undated. Retrieved 8 April 2015
Bisphenol A website Polycarbonate/BPA Global Group, American Chemistry Council. Retrieved 8 April 2015
Bisphenol A articles Environmental Health Perspectives by NIEHS. Retrieved 8 April 2015 (200 articles)(open access)
Bisphenol A ChemSub Online. Retrieved 8 April 2015
How to Protect Your Baby from BPA (Bisphenol A) Brochure, 2 pages, 2009, Massachusetts Department of Public Health. Retrieved 8 April 2015
Plastic Not Fantastic with Bisphenol A 19 February 2008 By David Biello, www.scientificamerican.com. Retrieved 8 April 2015
Hazard in a bottle. The plastics industry's Pyrrhic victory Attempt to regulate BPA in California defeated, The Economist, 22 August 2008
Alternatives to BPA containers not easy for U.S. foodmakers to find Lyndsey Layton. Washington Post, 23 February 2010. Retrieved 8 April 2015
Hand sanitizer may increase BPA absorption in Science Friday, 24 October 2014.
bisphenol A U.S. FDA statement, 2008
Endocrine disruptors
Medical controversies
Nonsteroidal antiandrogens
Plasticizers
Xenoestrogens | Health effects of Bisphenol A | [
"Chemistry"
] | 16,056 | [
"Endocrine disruptors"
] |
57,553,626 | https://en.wikipedia.org/wiki/Glycerol%202-phosphate | Glycerol 2-phosphate is the conjugate base of phosphoric ester of glycerol. It is commonly known as β-glycerophosphate or BGP. Unlike glycerol 1-phosphate and glycerol 3-phosphate, this isomer is not chiral. It is also less common.
Applications
β-Glycerophosphate is an inhibitor of the enzyme serine-threonine phosphatase. It is often used in combination with other phosphatase/protease inhibitors for broad spectrum inhibition.
β-Glycerophosphate is also used to drive osteogenic differentiation of bone marrow stem cells in vitro.
β-Glycerophosphate is used to buffer M17 media for Lactococcus culture in recombinant protein expression.
Notes
Organophosphates | Glycerol 2-phosphate | [
"Chemistry",
"Biology"
] | 185 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry"
] |
57,554,421 | https://en.wikipedia.org/wiki/Pomeranchuk%20instability | The Pomeranchuk instability is an instability in the shape of the Fermi surface of a material with interacting fermions, causing Landau’s Fermi liquid theory to break down. It occurs when a Landau parameter in Fermi liquid theory has a sufficiently negative value, causing deformations of the Fermi surface to be energetically favourable. It is named after the Soviet physicist Isaak Pomeranchuk.
Introduction: Landau parameter for a Fermi liquid
In a Fermi liquid, renormalized single electron propagators (ignoring spin) are
where capital momentum letters denote four-vectors and the Fermi surface has zero energy; poles of this function determine the quasiparticle energy-momentum dispersion relation. The four-point vertex function describes the diagram with two incoming electrons of momentum and two outgoing electrons of momentum and and amputated external lines: Call the momentum transfer When is very small (the regime of interest here), the T-channel dominates the S- and U-channels. The Dyson equation then offers a simpler description of the four-point vertex function in terms of the 2-particle irreducible which corresponds to all diagrams connected after cutting two electron propagators: Solving for shows that, in the similar-momentum, similar-wavelength limit the former tends towards an operator satisfying where The normalized Landau parameter is defined in terms of as where is the density of Fermi surface states. In the Legendre eigenbasis the parameter admits the expansion Pomeranchuk's analysis revealed that each cannot be very negative.
Stability criterion
In a 3D isotropic Fermi liquid, consider small density fluctuations around the Fermi momentum where the shift in Fermi surface expands in spherical harmonics as The energy associated with a perturbation is approximated by the functional where Assuming , these terms are, and so
When the Pomeranchuk stability criterion is satisfied, this value is positive, and the Fermi surface distortion requires energy to form. Otherwise, releases energy, and will grow without bound until the model breaks down. That process is known as Pomeranchuk instability.
In 2D, a similar analysis, with circular wave fluctuations instead of spherical harmonics and Chebyshev polynomials instead of Legendre polynomials, shows the Pomeranchuk constraint to be In anisotropic materials, the same qualitative result is true—for sufficiently negative Landau parameters, unstable fluctuations spontaneously destroy the Fermi surface.
The point at which is of much theoretical interest as it indicates a quantum phase transition from a Fermi liquid to a different state of matter Above zero temperature a quantum critical state exists.
Physical quantities with manifest Pomeranchuk criterion
Many physical quantities in Fermi liquid theory are simple expressions of components of Landau parameters. A few standard ones are listed here; they diverge or become unphysical beyond the quantum critical point.
Isothermal compressibility:
Effective mass:
Speed of first sound:
Unstable zero sound modes
The Pomeranchuk instability manifests in the dispersion relation for the zeroth sound, which describes how the localized fluctuations of the momentum density function propagate through space and time.
Just as the quasiparticle dispersion is given by the pole of the one-particle propagator, the zero sound dispersion relation is given by the pole of the T-channel of the vertex function near small Physically, this describes the propagation of an electron hole pair, which is responsible for the fluctuations in
From the relation and ignoring the contributions of for the zero sound spectrum is given by the four-vectors satisfying Equivalently, where and
When the equation () can be implicitly solved for a real solution , corresponding to a real dispersion relation of oscillatory waves.
When the solution is pure imaginary, corresponding to an exponential change in amplitude over time. For the imaginary part damping waves of zeroth sound. But for and sufficiently small the imaginary part implying exponential growth of any low-momentum zero sound perturbation.
Nematic phase transition
Pomeranchuk instabilities in non-relativistic systems at cannot exist. However, instabilities at have interesting solid state applications. From the form of spherical harmonics (or in 2D), the Fermi surface is distorted into an ellipsoid (or ellipse). Specifically, in 2D, the quadrupole moment order parameter has nonzero vacuum expectation value in the Pomeranchuk instability. The Fermi surface has eccentricity and spontaneous major axis orientation . Gradual spatial variation in forms gapless Goldstone modes, forming a nematic liquid statistically analogous to a liquid crystal. Oganesyan et al.'s analysis of a model interaction between quadrupole moments predicts damped zero sound fluctuations of the quadrupole moment condensate for waves oblique to the ellipse axes.
The 2d square tight-binding Hubbard Hamiltonian with next-to-nearest neighbour interaction has been found by Halboth and Metzner to display instability in susceptibility of d-wave fluctuations under renormalization group flow. Thus, the Pomeranchuk instability is suspected to explain the experimentally measured anisotropy in cuprate superconductors such as LSCO and YBCO.
See also
Kohn anomaly
Pomeranchuk's theorem
Lindhard theory
References
Fermions | Pomeranchuk instability | [
"Physics",
"Materials_science"
] | 1,089 | [
"Fermions",
"Subatomic particles",
"Condensed matter physics",
"Matter"
] |
57,554,825 | https://en.wikipedia.org/wiki/Climate%20Policy%20Initiative | The Climate Policy Initiative (CPI) is an independent non-profit research group and international climate policy organization based in San Francisco, California with other offices worldwide. CPI is supported primarily by philanthropic organizations and government development finance.
With over 100 analysts and advisors the climate think tank works to improve energy and land use policies around the world, with a particular focus on finance. It is considered a leader expert group in tracking global climate finance.
Beginning with the Landscape of Climate Finance (2011), CPI has published a series of annual reports which examine both public and private financial flows worldwide. CPI also publishes in-depth case studies on the public sector's mobilization of private
investment.
As of 2021, CPI reported that flows of climate-related finance in and between countries account for only about 0.7% of the world’s GDP, far below the amount that is projected to be needed for climate mitigation and adaptation. The San Giorgio Group (SGG), a working group established by CPI and others in 2011, focuses on ways in which financing can support green low-emissions investment.
History
Founded in 2009 by Thomas Heller,
CPI is headquartered in San Francisco (United States). It also has offices in Rio de Janeiro (Brazil), New Delhi (India), Jakarta (Indonesia), and London (United Kingdom).
As of 2020, the Global Managing Director of the Climate Policy Institute is Barbara Buchner.
Current fields of research
Renewable energy & energy efficiency
Policy & institutions
Carbon finance
Climate & development (for the scientific journal see Climate and Development)
Forestry & land use
Publications
CPI has published about 200 studies on the previously listed fields of research, mainly in English, with some in Portuguese and Bahasa Indonesia (Malay). The studies are freely downloadable in its publications web page.
See also
Climate Finance
Global warming
External links
Climate Policy Initiative official website
References
Environmental research institutes
Climate change
Climate change organizations based in the United States
Economic research institutes
Nonpartisan organizations in the United States
Political and economic think tanks in the United States
Non-profit organizations based in San Francisco
Natural resource management
Organizations established in 2009 | Climate Policy Initiative | [
"Environmental_science"
] | 420 | [
"Environmental research institutes",
"Environmental research"
] |
57,557,150 | https://en.wikipedia.org/wiki/Donna%20Huryn | Donna M. Huryn is an American medicinal and organic chemist. She received her B.A. (chemistry) from Cornell University, and Ph.D. in organic chemistry from the University of Pennsylvania. She is on the faculty at the University of Pittsburgh’s school of pharmacy, holds an adjunct appointment in the department of chemistry at the University of Pennsylvania, is the principal investigator of the University of Pittsburgh Chemical Diversity Center, and was a visiting fellow in the summer of 2017 at the University of Bologna. She is a fellow of the American Chemical Society, recipient of the ACS Philadelphia Local Section Award, has held a number of elected positions within the American Chemical Society at both the local and national levels, and is 2015 Chair of the Division of Organic Chemistry. Huryn also formed, along with a number of other scientists, the Empowering Women in Organic Chemistry Conferences in 2019. The goal was to empower and bring the research and career of all marginalized individuals in chemistry-related fields to the forefront of the scientific community. Huryn noticed how there was not enough women pursuing and maintaining a career in organic chemistry, and thus founded this organization. The Empowering Women in Organic Chemistry Conferences allowed for women leaders to present their scientific findings and hear the stories of how eminent women in the field of organic chemistry overcame the challenges they faced being female. She is associate editor of ACS Medicinal Chemistry Letters. She in also an editor of the journal Organic Reactions and co-authored the textbook Medicinal Chemistry and the article "Medicinal Chemistry: Where Are All the Women?" which appeared in the ACS Medicinal Chemistry Letters Journal. Huryn’s research focuses on the design and synthesis of small molecules probes and drugs to treat cancer, neurodegenerative and infectious diseases.
References
Year of birth missing (living people)
Living people
University of Pennsylvania alumni
University of Pennsylvania faculty
Fellows of the American Chemical Society
Cornell University alumni
American organic chemists
American women chemists
American academic journal editors
University of Pittsburgh faculty
21st-century American chemists
21st-century American women scientists
American women academics
Chemistry
Organic chemistry | Donna Huryn | [
"Chemistry"
] | 418 | [
"Organic chemists",
"nan",
"American organic chemists"
] |
57,557,766 | https://en.wikipedia.org/wiki/Zaltoprofen | Zaltoprofen (JAN; trade name Soleton) is a nonsteroidal anti-inflammatory drug (NSAID) used as an analgesic, antipyretic, and anti-inflammatory agent. It is a selective COX-2 inhibitor and also inhibits bradykinin-induced pain responses without blocking bradykinin receptors.
It was approved for use in Japan in 1993.
References
COX-2 inhibitors
Nonsteroidal anti-inflammatory drugs
Carboxylic acids | Zaltoprofen | [
"Chemistry"
] | 100 | [
"Carboxylic acids",
"Functional groups"
] |
57,557,791 | https://en.wikipedia.org/wiki/Azuqua | Azuqua is an American cloud-based integration and automation company headquartered in Seattle, Washington. As such, they integrate SaaS applications and create automations that are designed to eliminate manual work. Azuqua's platform has the ability to set up workflows between multiple applications so disparate teams can stay in the loop. Azuqua's customers include companies such as Charles Schwab, General Electric, General Motors, HubSpot, and Airbnb.
History
Nikhil Hasija and Craig Unger founded Azuqua in 2011.
In 2013, the team participated in Techstars Microsoft's Windows Azure Accelerator, a Seattle-based incubator that helps entrepreneurs gain traction through deep mentor engagement and rapid iteration cycles.
Azuqua announced in 2014 that they have received their Series A funding from Ignition Partners which amounted to $5 million.
2017 included a 65% growth in new customers, a doubling of new SaaS connectors, and a 50% growth in overall employee headcount. Azuqua also received their Series B funding which totaled to $10.8 million. This funding was led by Insight Ventures Partners, with DFJ and Ignition Partners also joining the round
As of March 2018, Azuqua hired Todd Owens as CEO. Owens was previously CEO of Appuri, a customer data platform. Hasija has transitioned to the role of Chief Product Officer.
Azuqua also hired on Dan Kogan who has taken on the role of Chief Marketing Officer. Kogan previously worked at Tableau, a BI and analytics company, as a Senior Director of Product Marketing.
Okta acquired Azuqua in 2019.
Product Description/Features
Logic Library: Logic functions that can be used for data processing, branching logic, and business rules
Drag and Drop Visual Designer: No-code visual designer
Use of API's for each cloud service a business is using to allow the various apps to communicate and share data
API Publishing: Integrations and automations can be made available as secure endpoints, webhooks, or open services
Connector Builder: Build a connector to an application
Connector Library: Pre-built connectors to SaaS applications
Error Handling: Automations that execute when an error is detected
References
External links
https://azuqua.com/
https://www.rentabiliweb-group.com/
2011 establishments in Washington (state)
American companies established in 2011
Privately held companies based in Washington (state)
Data management | Azuqua | [
"Technology"
] | 504 | [
"Data management",
"Data"
] |
57,559,457 | https://en.wikipedia.org/wiki/Kevin%20Lynch%20Award | The Kevin Lynch Award of the Massachusetts Institute of Technology's Department of Urban Studies and Planning, established in 1988, is named in honor of the urban planner and author Kevin A. Lynch. It is given to individuals or organizations which contribute to research in city form.
Honorees
Starting in 2014, the awards have been presented in five categories. Earlier awards have been retroactively assigned to these categories.
Past winners:
Technology and Media in City Imaging
Jennifer Pahlka and Code for America (2014)
Manuel Castells (2001)
Richard Saul Wurman (1991)
Ecological Sustainability in City Form
Randolph T. Hester (2011)
Richard M. Daley (2005)
Preservation and Change in City Image
Barnaby Evans and William D. Warner (2003)
Allan Jacobs (1999)
William L. MacDonald (1989)
Justice and Efficiency in City Design
City of Vancouver Planning Department (2007)
Allan Heskin (1990s)
Eric Wolf (1989)
Urban Events and Ephemera
Barnaby Evans (2003)
Boston’s First Night (1990)
External links
Official site
Notes
Urban planning
Awards established in 1988
1988 establishments in Massachusetts
Massachusetts Institute of Technology | Kevin Lynch Award | [
"Engineering"
] | 229 | [
"Urban planning",
"Architecture"
] |
57,560,460 | https://en.wikipedia.org/wiki/Affect%20as%20information%20hypothesis | In cognitive psychology, the affect-as-information hypothesis, or 'approach', is a model of evaluative processing, postulating that affective feelings provide a source of information about objects, tasks, and decision alternatives. A goal of this approach is to understand the extent of influence that affect has on cognitive functioning. It has been proposed that affect has two major dimensions, namely affective valence and affective arousal, and in this way is an embodied source of information. Affect is thought to impact three main cognitive functions: judgement, thought processing and memory. In a variety of scenarios, the influence of affect on these processes is thought to be mediated by its effects on attention. The approach is thought to account for a wide variety of behavioural phenomena in psychology.
Informative functions of affect: reaction vs. arousal
The affect as information hypothesis emphasises significance of the information that affect communicates, rather than the affective feelings themselves. Affective reactions or 'responses' provide an embodied source of information about 'value' or valence, as well as affective arousal provides an embodied source of information about importance. More specifically, affective reactions are pleasant or unpleasant reactions that provide information on positive ('good') and negative ('bad') value, respectively. Objects, task situations, and other stimuli or targets- if experienced as the source of an affective reaction- take on the positive or negative affect value. Affective arousal involves implicit (stress hormonal response such as from the adrenergic system) or explicit responses (subjective experience) that provide information on relevance, urgency, or importance. Both dimensions are thought to affect cognitive functioning through influencing judgements and decision making, processing, and memory, and in a variety of situations this is thought to be mediated through its influences on attention.
Affect on judgement and decision making
Affective reaction
A finding by Schwarz and Clore (1988) has been noted in literature (for example,), wherein individuals are thought to review and attend to their affective reactions when making evaluative judgements and decisions. They typically ask themselves, "How do I feel about it". A broad example of this (which may be applied to a variety of situations) is when considering how much we like something. Our judgements are based on how we feel about a particular stimulus as opposed to the attributes or characteristics of the said stimulus. Essentially, if the object, task situation, or other stimulus is experienced as the source of an affective reaction and takes on the affect value, then a judgement or decision may be made about the stimulus based on these attributed feelings. Positive and negative affect typically lead to positive and negative judgements, respectively.
Affective arousal
Affective arousal is thought to intensify positive and negative affective reactions and, as a result, judgemental evaluations- as if relying on affective arousal to indicate how strongly one feels about something. An empirical example of this is findings of intensified evaluations under high affective arousal when watching advertisements. Advertisements with positive and negative affective tone were evaluated as more positive and negative respectively, under conditions of high affective arousal relative to under conditions of low affective arousal.
Attribution of affect
Affect may be elicited by the stimulus or situation of relevance, which is referred to as integral affect. Conversely, affect may be momentary and coincide in time with the presence of the relevant stimulus, but be unrelated to the stimulus. This is referred to as incidental affect. Integral affect provides meaningful, relevant information about a target stimulus on which a judgement or decision can be made. Incidental affect may lead to affective feelings being subsequently mis-attributed to the stimulus at hand and thus provide mistaken information about the stimulus, from which a mislead judgement or decision is formed.
Research examples
There is a variety of research investigating the influence of affect on judgement, and the misattribution of affect. One study in the area investigated affective valence. They induced positive and negative affective states based on a life event (happy versus sad), and the weather (sunny versus rainy). Induced positive affective states (good experiences, sunny weather) lead to more positive evaluations of ratings of general well-being, relative to in an induced negative affective state (sad experiences, rainy weather), which lead to more negative life evaluations. They also found that negative life evaluations from an induced negative affective state was removed when the state was induced to be attributed to an irrelevant source (not to life satisfaction). This misattribution did not occur when in an induced positive affective state. Their conclusion was that the results indicate that affective state indirectly influenced judgements of life satisfaction through the type of information conveyed by affective feelings associated with life satisfaction.
Another study in the area illustrates misattribution, and an effect of affective arousal on judgement. They induced high affective arousal in the experimental condition where participants had to cross a high bridge, and a low affective arousal state in the control condition where participants had to cross a low bridge. All participants were male, and met an attractive female demonstrator on the other side of the bridge. They found that participants in the induced high affective arousal condition contacted the attractive demonstrator after the experiment significantly more than those in the induced low affective arousal condition. Males with a high affective arousal state had amplified attraction to the woman, as they misattributed their feelings of arousal caused by the bridge, to feelings of affective arousal caused by the attractive woman.
Affect on cognitive processing
Affect has been indicated to provide information about how benign versus problematic a situation or task is, which is dependent on the type of affective reaction or arousal. Consequently, this influences the type of information processing style that is used to interpret the situation.
Affective reaction
If the affect is attributed as a response to a situation or stimulus then positive affect signals a benign situation that promotes relational processing which involves primarily top down processing of information. Conversely, negative affect signals a problematic situation, inhibiting processing associated with positive affect and promoting referential processing which is associated primarily with bottom up processing.
Global vs. local processing
An example of the influence of affect on processing style is that of its influence on the use of a global versus a local focus. Positive affect is thought to induce a more global processing style (processing of wholes). Conversely, negative affect reduces global processing and enhances a more local processing style (processing of parts or details).
Other research in this area has illustrated that the informative influence of affective valence is dependent on the accessibility of these global and local processing styles. In situations when either a global or local style was more accessible, positive affect lead to a greater increase in global or local processing respectively, compared to negative affect.
Stereotypical thought processing
Affective valence has also been indicated to have informative effects on stereotypical thought processing. Positive affect is thought to lead to increased stereotypical thought processing, illustrated in research where participants in an induced positive mood were more likely than those in an induced neutral mood or negative mood to make a stereotypical judgement. This was suggested to be due to stereotypical thought elicited from the positive affect. Additionally, negative affect has been demonstrated to lead to decreased stereotypical thought processing.
Affective arousal
As in the effect of arousal in judgement, affective arousal is proposed to intensify cognitive processing that has been induced as a result of information provided by affective valence. An illustration is that empirical research on false memories showed with high affective arousal, more false memories were produced within different valence conditions (positive, negative, neutral) than with low affective arousal.
Affect on memory
Affective reaction
Affective arousal has predominantly been discussed with regard to the informative influence of affect on memory. However, the influence of affective valence on memory has been demonstrated in research, such as at memory retrieval. It was illustrated that after exposure to pleasant or unpleasant odours to induce positive or negative affective valence respectively, those with induced positive affect provided significantly more positive ratings (rated as happy memory) of a retrieved memory than those with induced negative affect. Affective valence has also been implicated at memory encoding.
Affective arousal
Affective arousal has been indicated to influence memory as it redirects or narrows attention towards potentially important or salient factors such as environmental stimuli, thus influencing what information gets encoded in to memory. As mentioned, this effect is mediated by implicit and explicit affective arousal responses, indicative of the level of importance in a situation. Affective arousal has also been implicated in consolidation of long-term memory through the mediating effects of stress hormones of the adrenergic system as shown by functional connectivity between the amygdala and the hippocampus- whose functions include memory consolidation.
Research example
Empirical research investigating both affective valence and arousal found effects on different aspects of memory. In their research, they investigated the effect of induced positive versus negative affective valence, and induced high and low arousal on memory encoding using picture slides, in a delayed (to assess long-term memory) and immediate free-recall task. In both free recall conditions, high arousal at encoding lead to better memory performance than low arousal at encoding. A similar finding occurred for affective valence where positive affect at encoding lead to better memory performance, however only for the immediate free-recall condition. They concluded that their results indicate the influence of both dimensions of affect at encoding, and involvement of affective arousal in long-term memory.
History
Development of the early theory
A researcher in the field of cognitive psychology by the name of Norbert Schwarz was interested in the informative function of feelings. He commenced research alongside Robert Wyer and Gerald Clore. Building off the ideas of earlier works, one he summarised was that current feelings elicited increase the availability of information congruent with that feeling. He recognised that these ideas were developed upon by the earlier researchers; Isen, Shalker, Clark, and Karp (1978), and Bower (1981), who were researching affect and cognitive functioning. Additionally, the influential idea in this field stemming from the work of Wyer and Carlston (1979) was that a function of affect is to provide information about a target. Their investigation into the functions of feelings gave further insight into the informative functions of feelings, from which they derived core postulates of their theory. Development of the theory and postulates derived are detailed and summarised in Schwarz's (2010) 'Feelings as information theory'.
References
Cognitive psychology
Psychological theories | Affect as information hypothesis | [
"Biology"
] | 2,155 | [
"Behavioural sciences",
"Behavior",
"Cognitive psychology"
] |
57,560,504 | https://en.wikipedia.org/wiki/Hitchhiker%201 | Hitchhiker 1 (or Hitchhiker P-11 4201) was a satellite launched by U.S. Air Force on June 27, 1963. It was launched with the aim of studying and measuring cosmic radiation. The satellite was the first successful satellite of the P-11 program, following the failure of the first Hitchhiker satellite in March 1963.
Instruments
1 Geiger tube (40-4 MeV)
1 Faraday cup plasma
1 Electron detector (0.3-5.0 MeV)
1 Proton detector (0.7-5.3 MeV)
2 electrostatic analysers (4-100 keV)
See also
Corona program
References
1963 in spaceflight
Derelict satellites orbiting Earth | Hitchhiker 1 | [
"Astronomy"
] | 146 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
57,561,448 | https://en.wikipedia.org/wiki/NOTCH2NL | Notch homolog 2 N-terminal-like is a family of proteins that in humans consists of 3 proteins (NOTCH2NLA, NOTCH2NLB, and NOTCH2NLC) and is encoded by NOTCH2NL gene. It appears to play a key role in the development of the prefrontal cortex, a part of the brain.
NOTCH2NL increases the number of cortical stem cells, which while delaying the generation of neurons ultimately leads to a greater number of neurons and larger brains. NOTCH2NL copy number loss and gain is associated with various neurological disorders, and they showed that loss of NOTCH2NL in cortical organoids leads to the organoids being smaller, while resulting in premature differentiation of cortical stem cells into neurons. The role of NOTCH2NL in the development of the human brain together with the evolutionary history of NOTCH2NL genes, suggests that the emergence of NOTCH2NL genes may have contributed to the increase in size of the human neocortex which tripled over the last two million years.
References
Population genetics
Phylogenetics | NOTCH2NL | [
"Biology"
] | 219 | [
"Bioinformatics",
"Phylogenetics",
"Taxonomy (biology)"
] |
57,561,498 | https://en.wikipedia.org/wiki/Isaac%20Newton%20Gargoyle | Isaac Newton Gargoyle is an outdoor 1988–1989 hammered copper sheet relief depicting Isaac Newton by Wayne Chabre, installed on the exterior of Willamette Hall on the University of Oregon campus, in Eugene, Oregon. The sculpture is part of the collection of the Oregon Arts Commission, and administered by the University of Oregon. It was surveyed by the Smithsonian Institution's "Save Outdoor Sculpture!" program in 1994.
The piece is one of a series by Chabre at the Eugene campus that includes scientists and mathematicians Albert Einstein (Einstein Gargoyle, 1986), Marie Curie (Marie Curie Gargoyle, 1989), James Clerk Maxwell (Maxwell & Demon Gargoyle, 1989), Alan Turing (Alan Turing, 1988), John von Neumann (John von Neumann, 1987), and Thomas Condon; a fruit fly (Drosophila Fly Head, 1988); and a school of zebrafish.
References
1989 sculptures
Copper sculptures in Oregon
Cultural depictions of Isaac Newton
Outdoor sculptures in Eugene, Oregon
Sculptures by Wayne Chabre
Sculptures of men in Oregon
University of Oregon campus | Isaac Newton Gargoyle | [
"Astronomy"
] | 221 | [
"Cultural depictions of Isaac Newton",
"Cultural depictions of astronomers"
] |
57,561,917 | https://en.wikipedia.org/wiki/Trancitor | The trancitor as the combined word of a "transfer-capacitor" is to be considered as another active-device category besides the transistor as a "transfer-resistor". As observed in the table shown, four kinds of active devices are theoretically deduced. Among them, trancitors are missing to be the third and fourth kinds, whereas transistors, such as bipolar junction transistor (BJT) and field-effect transistor (FET), were already invented as the first and second kinds, respectively. Unlike the transistor switching the current at its output (i.e., current source), the trancitor transfers its input to the voltage output (i.e., voltage source), so an inverse relationship with each other.
History
The term, trancitor, and its concept were first conceived by Sungsik Lee, a professor at the Department of Electronics Engineering, Pusan National University, South Korea, through his article, entitled A Missing Active Device — Trancitor for a New Paradigm of Electronics, in arXiv uploaded on 30 April 2018, and published on 23 August 2018 in IEEE Access. And the supplementary video was also publicised. This story was first featured by the MIT Technology Review on 23 May 2018, entitled Another "Missing" Component could Revolutionize Electronics. Since then, it has been distributed and discussed by many other internet media and communities.
See also
Electrical element
Memristor
References
External links
Professor Sungsik Lee's homepage
Electrical components
Semiconductor devices
Non-invented electrical components | Trancitor | [
"Technology",
"Engineering"
] | 325 | [
"Electrical engineering",
"Electrical components",
"Components"
] |
57,563,051 | https://en.wikipedia.org/wiki/Institute%20of%20Forestry%20and%20Environmental%20Sciences | Institute of Forestry and Environmental Sciences, CU (IFESCU) was established in 1976 as Institute of Forestry with the help of Ministry of Environment and Forest, and Bangladesh Forest Department, under University of Chittagong, Bangladesh. It's the pioneer institute for forestry education in Bangladesh. Later, it was renamed as Institute of Forestry and Environmental Sciences in 1996. The Institute started providing in-service training (Master of Forestry) to newly recruited ACF (Assistant Conservator of Forests) in 1977–78, regular 4-year B.Sc. (Hons.) in Forestry in 1978–79, M.Sc. in Forestry in 1996, B.Sc. (Hons.) in Environmental Science in 2000-2001 and M.Sc. in Environmental Science in 2004.
See also
Forestry in Bangladesh
References
External links
University of Chittagong
Forestry education
Forestry in Bangladesh
Environmental research institutes
Research institutes in Bangladesh | Institute of Forestry and Environmental Sciences | [
"Environmental_science"
] | 186 | [
"Environmental research institutes",
"Environmental research"
] |
51,374,589 | https://en.wikipedia.org/wiki/Slovak%20Organisation%20for%20Space%20Activities | Slovak Organization for Space Activities - SOSA () is non-governmental organization based in Bratislava, Slovakia that promotes space-related research and technologies nationally. The organization supports Slovak activities with the European Space Agency (ESA) and the European Southern Observatory (ESO), developed skCUBE, the first Slovak satellite, and organizes events to promote space-related research and industry.
Goals
SOSA promotes space-related research and technologies within the Slovak Republic. Its members include specialists, professionals and students. SOSA has used meteorological balloons to perform experiments at the edge of space. It organises space-themed educational projects and competitions, and enabled students to work on the development of its first probe skCube.
Projects
Stratospheric Balloon - skBalloon
SOSA's first project started in 2008, sending meteorological balloons to the stratosphere. The project was named skBalloon. Its goal was to develop a re-usable probe that could be flown to near space, an altitude of 35–40 km, with a payload of technical experiments. The project became a commercial venture in 2013 under the company name GoSpace.
First Slovak Satellite - skCUBE
skCube is SOSA's project to design, construct, launch, operate and analyze data from CubeSat 1U. The satellite is 10x10x10cm in size and weighs 1056g. Slovak specialists participated in the development of Magion class satellites in the 1970s and space probes have components built in Slovakia. The goal was to launch a probe which will be designed, constructed and managed from Slovakia, which would be the country's first satellite launched since independence in 1993. The satellite was successfully launched on board a PSLV rocket from Sriharikota, India on June 23, 2017.
References
External links
Evidence of Civil Associations: Ministry of Interior of the Slovak Republic, [2013-01-05] Available online
Primary website
skCube website
Articles about astronautics
Slovakian discussion forum about astronautics
Organisations based in Bratislava
Science and technology in Slovakia
Scientific organisations based in Slovakia
Space organizations | Slovak Organisation for Space Activities | [
"Astronomy"
] | 418 | [
"Astronomy organizations",
"Space organizations"
] |
51,376,302 | https://en.wikipedia.org/wiki/Glivenko%27s%20theorem%20%28probability%20theory%29 | In probability theory, Glivenko's theorem states that if , are the characteristic functions of some probability distributions respectively and almost everywhere, then in the sense of probability distributions.
References
Theory of probability distributions
Probability theorems | Glivenko's theorem (probability theory) | [
"Mathematics"
] | 46 | [
"Theorems in probability theory",
"Mathematical theorems",
"Mathematical problems"
] |
51,376,356 | https://en.wikipedia.org/wiki/Huangguan%20Escalator | The Huangguan Escalator (, also known as the Lianglukou Escalator) is an escalator in Chongqing, China.
Constructed in 1993 and completed in 1996, the Huangguan Escalator was the highest single-grading escalator in China and Asia when it was built. Currently, it is the third highest escalator in Asia, after the escalator in Rustaveli station in the Tbilisi Metro (60 meters high) and an escalator in Pyongyang, North Korea. It is long and wide, with a height of about , and connects the Chongqing railway station at Caiyuanba to Lianglukou metro station. Due to the hilly nature of the terrain, the Lianglukou metro station is at the top of the escalator while the Chongqing railway station is at the bottom.
The escalator replaced an earlier funicular railway. The material used for building the escalator was imported, and the design and construction were directed by a local engineer, who also directed the construction of Chongqing Amusement Park.
There is a small charge for using the escalator, and it is monitored by a supervisor at each end. It takes 2.5 minutes for a passenger to finish a one-way trip on the escalator.
The escalator plays a key role in the civil transportation of the mountainous city Chongqing.
References
Yuzhong District
Vertical transport devices
Transport in Chongqing | Huangguan Escalator | [
"Technology"
] | 299 | [
"Vertical transport devices",
"Transport systems"
] |
51,377,115 | https://en.wikipedia.org/wiki/Dell%20Technologies | Dell Technologies Inc. is an American multinational technology company headquartered in Round Rock, Texas. It was formed as a result of the September 2016 merger of Dell and EMC Corporation (which later became Dell EMC). Dell Technologies ranked 48th on the 2024 Fortune 500 rankings of the largest United States corporations based on its 2023 revenue; its products include personal computers, servers, monitors, computer software, computer security and network security, as well as information security services.
History
Dell Technologies' predecessor Dell Inc. had returned to private ownership in 2013, claiming that it faced bleak prospects and would need several years out of the public eye to rebuild its business.
EMC was being pressured by Elliott Management Corporation, a hedge fund holding 2.2% of EMC's stock, to reorganize the unusual "Federation" structure, in which EMC's divisions were effectively being run as independent companies. Elliott argued this structure deeply undervalued EMC's core "EMC II" data storage business, and that increasing competition between EMC II and VMware products was confusing the market and hindering both companies.
The Wall Street Journal estimated that in 2014 Dell had revenue of $27.3 billion from personal computers and $8.9 billion from servers, while EMC had $16.5 billion from EMC II, $1bn from RSA Security, $6bn from VMware, and $230 million from Pivotal Software.
On October 12, 2015, Dell announced its intent to acquire EMC Corporation, an enterprise software and storage company, in a $67 billion transaction. It was then the largest acquisition in technology sector history. In addition to Michael Dell, Singapore's Temasek Holdings and Silver Lake Partners were major Dell shareholders that supported the transaction. The deal to buy EMC was closed on September 7, 2016. It reportedly generated about $40 billion in debt for Dell.
The Dell Services, Dell Software Group, and the Dell EMC Enterprise Content Divisions were sold shortly thereafter for proceeds of $7.0 billion, which was used to repay debt. In October 2017, It was reported that Dell would invest $1 billion in IoT research and development.
EMC owned around 80% of the stock of VMware. The acquisition maintained VMware as a separate company, held via a new tracking stock, while the rest of EMC were rolled into Dell.
The acquisition required Dell to publish quarterly financial results, having ceased these on going private in 2013.
In 2018, Dell had a racing partnership with British racing team McLaren, providing processing power to support the large amounts of racing data generated by McLaren's Formula 1 program.
On April 15, 2021, it was reported that Dell Technologies would spin out the remainder of its VMware shares to shareholders. The two companies would continue to operate without major changes for at least five years.
As of FY 2024, approximately 50% of the company's revenue is derived in the United States.
IPO
On January 29, 2018, it was reported that Dell Technologies was considering a reverse merger with its VMware subsidiary to take the company public.
On December 28, 2018, Dell Technologies became a public company, bypassing the traditional IPO process by buying back shares that tracked the financial performance of VMware.
Business
Dell Technologies has products and services in the field of scale-out architecture, converged infrastructure and private cloud computing.
Dell operates under two divisions:
Dell Client Solutions Group (55.3% of fiscal 2024 revenues) – produces desktop PCs, notebooks, tablets, and peripherals, such as monitors, printers, and projectors under the Dell brand name
Dell Infrastructure Solutions Group (38.3% of fiscal 2024 revenues) – servers, storage, and networking
References
External links
2016 establishments in Texas
American companies established in 2016
2018 initial public offerings
Cloud computing providers
Companies based in Round Rock, Texas
Companies listed on the New York Stock Exchange
Computer companies established in 2016
Computer companies of the United States
Computer hardware companies
Computer storage companies
Consumer electronics brands
Display technology companies
Electronics companies established in 2016
Home computer hardware companies
Manufacturing companies based in Texas
Manufacturing companies established in 2016
Mobile phone manufacturers
Multinational companies headquartered in the United States
Netbook manufacturers
Networking hardware companies
Private equity portfolio companies
Silver Lake (investment firm) companies
Family-owned companies of the United States | Dell Technologies | [
"Technology"
] | 879 | [
"Computer hardware companies",
"Computers"
] |
51,379,294 | https://en.wikipedia.org/wiki/John%20Devonshire%20Ellis | John Devonshire Ellis (20 April 1824 – 11 November 1906) was a steelmaker from Sheffield, England. He developed armour-plating for warships, and worked on the Bessemer process of steelmaking.
Early life
Ellis was born in Handsworth on 20 April 1824, son of Charles Ellis, a Birmingham brass manufacturer, and was educated at King Edward VI School, Birmingham. He obtained a practical knowledge of the manufacture and working of brass in his father's works, and in 1848 became a partner in the firm.
On 5 December 1848 he married Elizabeth Parsons Bourne of Childs Ercall, Shropshire.
Armour-plate for warships
In 1854 he purchased with John Brown and William Bragge the Atlas engineering works in Sheffield, then a modest establishment covering about three acres. Shortly after the partners took over the works, the adoption of armour for warships in France (1858) led the company to produce iron plates by a new and cheaper process of rolling welding them. Four-inch plates made by this process were fitted to and , the earliest ironclads of the British Royal Navy.
For several years Ellis was occupied in devising appliances for the manufacture of thicker plates to protect ships against guns and projectiles. Steel was tried, but was not found to have the necessary toughness under the impact of shot. After many experiment Ellis perfected a process for uniting a hard steel face with a wrought-iron backing. Such compound armour was used until about 1893, the s being protected with an 18-inch belt of this on the water-line. Meanwhile, as early as 1871, Ellis had turned his attention to the process of cementation, and in that year he took out a patent relating to it; but it was not until the chilling process devised by Captain T. J. Tresidder (in which the heated surface of a plate was chilled by means of water under pressure) was applied in conjunction with cementation, that satisfactory results were obtained. The first Ellis-Tresidder chilled compound plate was tried with success at Shoeburyness in 1891.
Bessemer process and other developments
Ellis was largely instrumental in promoting the success of the Bessemer process. Sir Henry Bessemer established works close to the Atlas works, and Ellis, adopting at an early stage the new process, then established at the Atlas works the first plant in England outside the inventor's own works.
In conjunction with William Eaves he introduced the Ellis-Eaves system of induced draught, and he devised a mill for rolling the ribbed boiler-flues of the Purves and other types, and also in connection with the manufacture of Serve tubes.
The Atlas works soon acquired a worldwide reputation for mechanical engineering of all kinds. The concern was formed into a limited liability company in 1864. The capital rose to nearly three millions sterling; about 10,000 men were employed at Ellis's death, and the output exceeded 100,000 tons of steel per annum. Ellis was managing director from 1864 until 1905, when he became chairman of the company. Brown retired in 1870 and Bragge died in 1884, when Ellis acquired sole charge. In 1899 the Clydebank Shipbuilding and Engineering Works, employing 8000 men, were taken over by the concern.
Awards and later life
In 1867 Ellis was decorated with the Cross of the Order of Vasa in recognition of his aid in certain fortifications in Sweden. From the Iron and Steel Institute, of which he was a member from 1875, a member of council in 1888, and a vice-president in 1901, he received the Bessemer Gold Medal in 1889, when Sir Henry Bessemer acknowledged Ellis's services in establishing the process. He was elected a member of the Institution of Civil Engineers on 8 January 1884. He took little part in the public affairs of Sheffield, but was a magistrate for the West Riding, and was for ten years chairman of the South Yorkshire Coalowners' Association.
He died at his residence in Worksop on 11 November 1906 and was buried at Carlton in Lindrick.
His son William Henry Ellis was also a steelmaker in Sheffield.
References
Attribution
External links
The Devonshire Ellis family
1824 births
1906 deaths
Businesspeople from Birmingham, West Midlands
English industrialists
English metallurgists
Bessemer Gold Medal
Institution of Civil Engineers
People from Worksop
People from Handsworth, West Midlands
19th-century English businesspeople | John Devonshire Ellis | [
"Chemistry"
] | 883 | [
"Bessemer Gold Medal",
"Chemical engineering awards"
] |
51,380,802 | https://en.wikipedia.org/wiki/Eulerian%20coherent%20structure | In applied mathematics, objective Eulerian coherent structures (OECSs) are the instantaneously most influential surfaces or curves that exert a major influence on nearby trajectories in a dynamical system over short time-scales, and are the short-time limit of Lagrangian coherent structures (LCSs). Such influence can be of different types, but OECSs invariably create a short-term coherent trajectory pattern for which they serve as a theoretical centerpiece. While LCSs are intrinsically tied to a specific finite time interval, OECSs can be computed at any time instant regardless of the multiple and generally unknown time scales of the system.
In observations of tracer patterns in nature, one readily identifies short-term variability in material structures such as emerging and dissolving coherent features. However, it is often the underlying structure creating these features that is of interest. While individual tracer trajectories forming coherent patterns are generally sensitive with respect to changes in their initial conditions and the system parameters, OECSs are robust and reveal the instantaneous time-varying skeleton of complex dynamical systems. Despite OECSs are defined for general dynamical systems, their role in creating coherent patterns is perhaps most readily observable in fluid flows. Therefore, OECSs are suitable in a number of applications ranging from flow control to environmental assessment such as now-casting or short-term forecasting of pattern evolution, where quick operational decisions need to be made. Examples include floating debris, oil spills, surface drifters, and control of unsteady flow separation.
References
Dynamical systems
Fluid dynamics | Eulerian coherent structure | [
"Physics",
"Chemistry",
"Mathematics",
"Engineering"
] | 329 | [
"Dynamical systems",
"Chemical engineering",
"Mechanics",
"Piping",
"Fluid dynamics"
] |
51,381,753 | https://en.wikipedia.org/wiki/B-H%20analyzer | A B-H Analyzer is an instrument that measures the AC magnetic characteristics of soft magnetic materials. It measures residual flux density BR and coercive force HC. It has applications in manufacturing magnetic-related products such as hard disks and magnetic tape, and in analysis of cast irons.
See also
B field and H field
Magnetic hysteresis
Saturation (magnetic)
References
External links
Photograph of the SY-8218, a common B-H Analyzer
Scientific Devices
Magnetism
Measuring instruments
Laboratory equipment | B-H analyzer | [
"Technology",
"Engineering"
] | 103 | [
"Measuring instruments"
] |
39,938,812 | https://en.wikipedia.org/wiki/AANAT%20%28gene%29 | AANAT is a gene that encodes an enzyme aralkylamine N-acetyltransferase. It is the key regulator of day-night cycle (circadian rhythm). It is found in all animals. In humans it is present on chromosome 17, in chimpanzees chromosome 17, in mouse and sheep chromosome 11, in rat chromosome 10, and in chicken chromosome 18.
Function
The protein encoded by this gene belongs to the acetyltransferase superfamily. It is the penultimate enzyme in melatonin synthesis and controls the night/day rhythm in melatonin production in the vertebrate pineal gland. Melatonin is essential for the function of the circadian clock that influences activity and sleep. This enzyme is regulated by cAMP-dependent phosphorylation that promotes its interaction with 14-3-3 proteins and thus protects the enzyme against proteasomal degradation.
Clinical significance
This gene may contribute to numerous genetic diseases such as delayed sleep phase syndrome.
References
Circadian rhythm
External links | AANAT (gene) | [
"Biology"
] | 213 | [
"Behavior",
"Sleep",
"Circadian rhythm"
] |
39,939,294 | https://en.wikipedia.org/wiki/Magnesium%20chromate | Magnesium chromate is a chemical compound, with the formula . It is a yellow, odorless, water-soluble salt with several important industrial uses. This chromate can be manufactured as a powder.
History
Before 1940, the literature about magnesium chromate and its hydrates was sparse, but studies starting in that year looked at its properties and solubility.
Uses
It is available commercially in a variety of powders, from nanoscale to micron-sized, either as an anhydrous or hydrated form.
As a hydrate, it is useful as a corrosion inhibitor and pigment, or as an ingredient in cosmetics.
In 2011, an undecahydrate (containing 11 molecules of water) of this compound was discovered by scientists at the University College London.
Hazards
Magnesium chromate hydrate should be stored at room temperature, and there is no current therapeutic use. It is a confirmed carcinogen, and can cause acute dermititis, and possibly kidney and liver damage if inhaled, so it should be treated as a hazardous waste.
References
Magnesium compounds
Chromates | Magnesium chromate | [
"Chemistry"
] | 225 | [
"Chromates",
"Oxidizing agents",
"Salts"
] |
39,939,331 | https://en.wikipedia.org/wiki/Janis%20Bubenko | Janis Askolds Bubenko junior (; 3February 193515January 2022) was a Swedish computer scientist and professor emeritus at the Department of Computer and Systems Science, Royal Institute of Technology and Stockholm University.
Biography
Born 1935 in Riga, Latvia, Bubenko fled with his family to Sweden at the end of World War II in 1944. He received his MSc in civil engineering from the Chalmers University of Technology in Gothenburg, Sweden, in 1958, his Licentiate of Technology in structural mechanics also from the Chalmers University of Technology in 1958. In 1973 he received his Ph.D. in information systems from the Royal Institute of Technology in Stockholm in 1973, and his habilitation in 1974.
In 1961 Bubenko started his career as a manager in Univac Scandinavia, a branch of the U.S. computer company Univac. In 1965 he started as an assistant professor at the Royal Institute of Technology, where in 1969 he founded the research group Computer Aided Design of Information Systems (CADIS). From 1977 to 1981 he was a professor of computer and systems sciences at University of Gothenburg and Chalmers University of Technology, and from 1981 to 2000 professor at the Royal Institute of Technology and University of Stockholm.
Bubenko has chaired multiple information systems conferences since the late 1970s. He is member of Association for Computing Machinery (ACM), the Institute of Electrical and Electronics Engineers (IEEE) Computer Society, and the International Federation for Information Processing (IFIP) Working Group 8.1.
Bubenko died on 15 January 2022 in Lund, Sweden, at the age of 86.
Publications
Bubenko authored and co-authored more than 140 articles, and seven textbooks in the fields of "Information Systems Development Methods, Performance Analysis of Data Processing Systems, Operating Systems, and Conceptual Modelling Methods". Books, a selection:
1971. Computer-aided information systems analysis and design. The first Scandinavian workshop. With Arne Sølvberg and Börje Langefors (Eds).
1973. Contributions to formal description, analysis and design of data processing systems. Stockholm. Libris
2000. Information systems engineering: state of the art and research themes. With Sjaak Brinkkemper, Eva Lindencrona and Arne Sølvberg.
2003. Working Conference on the History of Nordic Computing (1st : 2003 : Trondheim, Norway) History of Nordic computing : IFIP WG9.7 First Working Conference on the History of Nordic Computing (HiNC1), June 16–18, 2003, Trondheim, Norway. Edited with Arne Sølvberg and John Impagliazzo.
Articles, a selection:
2007. "From Information Algebra to Enterprise Modelling and Ontologies - a Historical Perspective on Modelling for Information Systems". In: Conceptual Modelling in Information Systems Engineering. John Krogstie et al. eds. pp 1–18
References
External links
Janis A. Bubenko jr at Royal Institute of Technology in Stockholm
1935 births
Information systems researchers
Swedish computer scientists
Academic staff of the KTH Royal Institute of Technology
Chalmers University of Technology alumni
Latvian emigrants to Sweden
Latvian World War II refugees
2022 deaths | Janis Bubenko | [
"Technology"
] | 649 | [
"Information systems",
"Information systems researchers"
] |
39,940,749 | https://en.wikipedia.org/wiki/NGC%203185 | NGC 3185 is a spiral galaxy located 20.4 Mpc away in the Leo constellation. NGC 3185 is a member of a four-galaxy group called HCG 44. It is also a member of the NGC 3190 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.
References
External links
Barred spiral galaxies
3190
05554
030059
+04-24-024
10148+2156
Leo (constellation)
185001?? | NGC 3185 | [
"Astronomy"
] | 118 | [
"Leo (constellation)",
"Constellations"
] |
39,941,202 | https://en.wikipedia.org/wiki/G-strain | In EPR spectroscopy, g-strain refers to broadening of g-values owing to small sample inhomogeneity owing to slight variations in the orientation of the paramagnetic centers. The phenomenon is indicated by broadening of the g-values that depends on the frequency of the spectrometer, such as X- or Q-band. If the line width were determined only by hyperfine coupling (which are field-independent), then the line widths would also be field independent, but they often are not. In iron-sulfur proteins, some other metalloproteins, as well as some solids, g-strain can be substantial.
References
Spectroscopy | G-strain | [
"Physics",
"Chemistry"
] | 139 | [
"Instrumental analysis",
"Molecular physics",
"Spectroscopy",
"Spectrum (physical sciences)"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.