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54,321,473 | https://en.wikipedia.org/wiki/Chalconatronite | Chalconatronite is a carbonate mineral and rare secondary copper mineral that contains copper, sodium, carbon, oxygen, and hydrogen, its chemical formula is Na2Cu(CO3)2•3(H2O). Chalconatronite is partially soluble in water, and only decomposes, although chalconatronite is soluble while cold, in dilute acids. The name comes from the mineral's compounds, copper ("chalcos" in Greek) and natron, naturally forming sodium carbonate. The mineral is thought to be formed by water carrying alkali carbonates (possibly from soil) reacting with bronze. Similar minerals include malachite, azurite, and other copper carbonates. Chalconatronite has also been found and recorded in Australia, Germany, and Colorado.
Bronze Disease
Most chalconatronite formed on bronze and silver that have been treated with either sodium sesquicarbonate or sodium cyanide to prevent corrosion and bronze disease. The mineral has also been proven to form on the surface of copper artifacts after being treated with aqueous sodium carbonate. This formation by using sodium sesquicarbonate is undesirable by many antique collectors, as the mineral changes the patinas of copper artifacts. When the mineral forms, it can replace copper salts within the patina, and turn the color from a rich green to a blue-green or even black.
Historical Occurrence
The mineral was recorded in 1955 on three bronze artifacts from ancient Egypt, which were being held in the Fogg Art Museum at Harvard. Chalconatronite was found inside of two bronze figures (one depicting a seated Sekhmet, and another one depicting a group of cats and kittens) from around the late Nubian Dynasty or early Saite Period. Another chalconatronite specimen was found under a bronze censer from the late Coptic Period. The chalconatronite found on the censer formed over cuprite and some atacamite crystals, which are associated minerals.
Chalconatronite was also found on iron and copper Roman armor in 1982 at a site in Chester, England. Some of the mineral was found on a copper pin in St. Mark's Basilica, Venice and in two different Mayan paintings. Along with pseudomalachite, chalconatronite was found on an illuminated manuscript from the sixteenth century. Synthetic chalconatronite could have possibly been made in ancient China as a form of pigment, named "synthetic malachite". It was made by taking copper oxide and boiling it with white alum in a "sufficient amount of water". After the result is cooled, a natron solution would be added to precipitate a synthetic form of chalconatronite, as sodium copper carbonate.
See also
Atacamite
Cuprite
Patina
Botallackite
Bronze disease
References
Carbonate minerals
Copper(II) minerals
Corrosion
Minerals | Chalconatronite | [
"Chemistry",
"Materials_science"
] | 601 | [
"Metallurgy",
"Electrochemistry",
"Materials degradation",
"Corrosion"
] |
54,322,333 | https://en.wikipedia.org/wiki/Django%20Girls | Django Girls is an international non-profit organization started by two Polish women, Ola Sitarska and Ola Sendecka, to inspire women from all backgrounds to get interested in technology and to become programmers, offering a safe and friendly environment. It is known for the free workshops it hosts to help women to learn to program and for its Django tutorial. It is often supported by the Python Software Foundation, and they often hold sessions at the Python Conference.
History
The first Django Girls workshop, which kicked off Django Girls, happened during EuroPython 2014, in Berlin. Ola Sitarska and Ola Sendecka decided to use Django and Python because both are open source code platforms, which may help women developing their own ideas. Since then, the initiative has spread worldwide, reaching countries like Argentina, Australia, Bolivia, Brazil, Colombia, Ecuador, Ghana, Nigeria, United Kingdom, Peru, United States, Zimbabwe and many others.
Tutorial
The tutorial, which teaches how to create and deploy a blog application using Django, is maintained and updated by the Django Girls community, using Github. As of May 2018, the Django Girls tutorial has been published online in 14 languages besides its original English version. As of May 2018, more than 1,000,000 users have visited its website.
Django Girls workshops
Using a manual provided by the organization, Django Girls volunteers offer free one or two days workshops in many cities of the world, usually held during weekends. It is aimed at complete beginners, teaching about HTML, CSS, Python and Django. As of May 2018, 414 cities across 90 countries have hosted Django Girls workshops, with Accra, Athens, Florence, Kathmandu, Lagos, Lahore, Oxford, and São José dos Campos among them. As of May 2018, over 14,000 women have attended Django Girls workshops held across the globe.
References
External links
Organizations for women in science and technology
Python (programming language)
Women in science and technology
Computer science education
Women in computing | Django Girls | [
"Technology"
] | 421 | [
"Computer science education",
"Computer science",
"Organizations for women in science and technology",
"Women in science and technology"
] |
54,322,356 | https://en.wikipedia.org/wiki/Indonesian%20Food%20and%20Drug%20Authority | The Indonesian Food and Drug Authority (), Badan POM/BPOM, or Indonesian FDA is a government agency of Indonesia responsible for protecting public health through the control and supervision of prescription and over-the-counter pharmaceutical drugs (medication), vaccines, biopharmaceuticals, dietary supplements, food safety, traditional medicine and cosmetics. The task and purposes of this agency is similar to the USFDA.
History
The predecessor of BPOM was formed during the colonial period and was named (DVG). Operating under the auspices of the Dutch pharmaceutical company, DVG itself was in charge of producing chemical drugs as well as operating a pharmaceutical research center. In 1964, during the Guided Democracy era, DVG was nationalized and became the Pharmacy Inspectorate () of the Indonesian Ministry of Health. Three years later, it was renamed the Inspectorate of Pharmaceutical Affairs (). In 1976, it was again renamed the Directorate General Drug and Food Control (, Ditjen POM).
In accordance with Presidential Decree No. 166/2000, the Directorate-General of Drug and Food Control was officially divested from the Ministry of Health to become an independent agency which reports directly to the president, though it continues to coordinate with the Ministry. Since 2017, BPOM has been regulated by Presidential Decree No. 80/2017.
In 2020, the head of BPOM issued a decree regarding the standardization of English-language nomenclature used in reference to BPOM, which includes an official translation of the agency name in English. The agency was previously known in English as the National Agency for Drug and Food Control.
Task and function
Task
As stipulated in article 2 of Presidential Decree No. 80/2017, BPOM was tasked to execute government role in the field of drug and food control.
Function
According to article 3 of Presidential Decree No. 80/2017, BPOM has the following functions:
Drafting and executing national policy in drug and food control;
Drafting and establish norms, standard, procedure, and criterion in supervision on before and after obtaining marketing authorisation;
Executing supervision before and after obtaining marketing authorisation;
Coordinating drug and food control within the central and regional governments;
Providing technical assistance and supervision in drug and food control;
Enforcing the law in regards to the field of drug and food control;
Coordinating execution, supervision and administrative support for all entity within BPOM;
Managing state assets within BPOM;
Overseeing task and functions execution within BPOM.
Organization
Based on article 5 of Presidential Decree No. 80/2017, and as expanded by BPOM Decrees No. 21/2020 and 13/2022, BPOM is organized into the following:
Head of Indonesian Food and Drug Authority
Secretariat General
Deputy for Drug Control, Narcotics, Psychotropics, Precursors and Addictive Substances Supervision
Directorate of Pharmaceutical, Narcotics, Precursors and Addictive Substances Standardization
Directorate of Pharmaceutical Registration
Directorate of Pharmaceutical, Narcotics, Psychotropics, and Precursors Production Supervision
Directorate of Pharmaceutical, Narcotics, Psychotropics, and Precursors Distribution Supervision
Directorate of Pharmaceutical, Narcotics, Psychotropics, Precursors, and Addictive Substances Safety, Quality, and Export-Import Supervision
Deputy for Traditional Medicines, Health Supplements, and Cosmetics Supervision
Directorate of Traditional Medicines, Health Supplements, and Cosmetics Standardization
Directorate of Traditional Medicines, Health Supplements, and Cosmetics Registration
Directorate of Traditional Medicines and Health Supplements Supervision
Directorate of Cosmetics Supervision
Directorate of Public and Business Empowerment in Traditional Medicines, Health Supplements, and Cosmetics
Deputy for Processed Food Supervision
Directorate of Processed Food Standardization
Directorate of Processed Food Registration
Directorate of Processed Food Production Supervision
Directorate of Processed Food Distribution Supervision
Directorate of Public and Business Empowerment in Processed Food
Deputy for Law Enforcement
Directorate of Prevention
Directorate of Food and Drug Intelligence
Directorate of Food and Drug Cyber
Directorate of Food and Drug Investigation
Inspectorate General
BPOM has four centers, those are:
Center of Drug and Food Data and Information
Center of Drug and Food Human Resource Development
Center of National Drug and Food Testing Development
Center of Drug and Food Policy Analysis
BPOM has several Technical Implementation Units (TIUs) which spread across Indonesia. TIUs in NAFDC are Bureau () and Office ().
References
External links
National Agency for Drug and Food Control of Indonesia
Government agencies of Indonesia
Government agencies established in 1936
1936 establishments in the Dutch East Indies
National agencies for drug regulation | Indonesian Food and Drug Authority | [
"Chemistry"
] | 869 | [
"National agencies for drug regulation",
"Drug safety"
] |
54,323,077 | https://en.wikipedia.org/wiki/LeDock | LeDock is a molecular docking software, designed for protein-ligand interactions, that is compatible with Linux, macOS, and Windows.
The software can run as a standalone programme or from Jupyter Notebook. It supports the Tripos Mol2 file format.
Methodology
LeDock utilizes a simulated annealing and genetic algorithm approach for facilitating the docking process of ligands with protein targets. The software employs a knowledge-based scoring scheme that is derived from extensive prospective virtual screening campaigns. It is categorized as a flexible docking method.
Performance
In a study involving 2,002 protein-ligand complexes, LeDock demonstrated a notable level of accuracy in predicting molecular poses. The Linux version contains command line tools to run automated virtual screening of different large molecular libraries in the cloud.
In a performance evaluation of ten docking programs, LeDock demonstrated strong sampling power when compared against other commercial and academic alternatives. According to a review from 2017, LeDock was noted for its effectiveness in sampling ligand conformational space, identifying near-native binding poses, and having a flexible docking protocol. The Linux version includes tools for high-throughput virtual screening in the cloud.
See also
Drug design
Macromolecular docking
Molecular mechanics
Molecular modelling
Protein structure
Protein design
List of software for molecular mechanics modeling
List of protein-ligand docking software
Molecular design software
Lead Finder
Virtual screening
Scoring functions for docking
References
External links
Official website
Medicinal chemistry
Drug discovery
Molecular modelling software | LeDock | [
"Chemistry",
"Biology"
] | 286 | [
"Molecular modelling software",
"Computational chemistry software",
"Drug discovery",
"Life sciences industry",
"Molecular modelling",
"nan",
"Medicinal chemistry",
"Biochemistry"
] |
54,323,368 | https://en.wikipedia.org/wiki/Morphism%20of%20algebraic%20stacks | In algebraic geometry, given algebraic stacks over a base category C, a morphism of algebraic stacks is a functor such that .
More generally, one can also consider a morphism between prestacks (a stackification would be an example).
Types
One particular important example is a presentation of a stack, which is widely used in the study of stacks.
An algebraic stack X is said to be smooth of dimension n - j if there is a smooth presentation of relative dimension j for some smooth scheme U of dimension n. For example, if denotes the moduli stack of rank-n vector bundles, then there is a presentation given by the trivial bundle over .
A quasi-affine morphism between algebraic stacks is a morphism that factorizes as a quasi-compact open immersion followed by an affine morphism.
Notes
References
Stacks Project, Ch, 83, Morphisms of algebraic stacks
Algebraic geometry | Morphism of algebraic stacks | [
"Mathematics"
] | 189 | [
"Fields of abstract algebra",
"Algebraic geometry"
] |
54,323,612 | https://en.wikipedia.org/wiki/Gliese%20877 | Gliese 877 (GJ 877 / HIP 113229 / LHS 531) is a red dwarf located in the southern constellation of Octans, near the boundary with Indus.
Gliese 877's bolometric luminosity is just 2.3% of the Sun's. It shines with an apparent magnitude of +10.22, so it cannot be seen with the naked eye. Nevertheless, it is considerably brighter than other red dwarfs, such as Proxima Centauri, the closest red dwarf to the Solar System; in particular, it is almost 14 times more luminous than Proxima. Of spectral type M3V, its effective temperature is 3390 K. It does not appear to be a variable star.
Gliese 877 is 28.1 light years from the Solar System. Known stars close to it are β Hydri and ζ Tucanae, respectively 4.5 and 6.2 light years.
See also
List of star systems within 25–30 light-years
References
0877
113229
Octans
M-type main-sequence stars | Gliese 877 | [
"Astronomy"
] | 231 | [
"Octans",
"Constellations"
] |
54,324,926 | https://en.wikipedia.org/wiki/Conserved%20oligomeric%20Golgi%20complex | The conserved oligomeric Golgi complex (COG) is a multiprotein complex found in the Golgi apparatus structure and involved in intracellular transport and glycoprotein modification.
Earlier names for this complex were: the Golgi transport complex (GTC), the LDLC complex, which is involved in glycosylation reactions, and the SEC34 complex, which is involved in vesicular transport. These 3 complexes are identical and are termed the conserved oligomeric Golgi (COG) complex.
Structure
The COG protein complex consists of eight subunits, in two lobes; Lobe A consists of COG1, COG2, COG3, COG4 and lobe B consists of COG5, COG6, COG7, COG8.
Function
The conserved oligomeric Golgi complex plays important roles in maintaining structure and transport mechanisms within the Golgi apparatus.
References
Protein complexes
External links
Role of the conserved oligomeric Golgi (COG) complex in protein glycosylation. Smith & Lupashin. 2008
The conserved oligomeric Golgi complex is required for fucosylation of N-glycans in Caenorhabditis elegans. 2012 | Conserved oligomeric Golgi complex | [
"Chemistry"
] | 265 | [
"Biochemistry stubs",
"Protein stubs"
] |
54,325,825 | https://en.wikipedia.org/wiki/Esso%20Research%20Centre | The Esso Research Centre was a research centre in Oxfordshire.
History
The site was Esso's main European technical centre for fuels and lubricants. The site was extended in 1957. Operations ceased in the early 2000s.
Structure
The site had the staff of Esso Research, with around 500 scientists and engineers.
Function
It conducted research into chemistry.
Location
It was situated on the western side of the A4130 (the original A34 trunk route) on Milton Hill, above Steventon, Oxfordshire. On disposal the site was split in two, between the headquarters of Infineum and the Milton Hill Business and Technology Centre. By 2018 the site had been cleared.
External links
Photos of pump/water tower in 2018 and 2013.
References
Engineering research institutes
Earth science research institutes
History of the petroleum industry in the United Kingdom
Petroleum organizations
Research institutes in Oxfordshire
Vale of White Horse
Energy research institutes
2000s disestablishments in England
ExxonMobil buildings and structures | Esso Research Centre | [
"Chemistry",
"Engineering"
] | 196 | [
"Engineering research institutes",
"Petroleum",
"Petroleum organizations",
"Energy research institutes",
"Energy organizations"
] |
52,999,026 | https://en.wikipedia.org/wiki/Junction-mediating%20and%20regulatory%20protein | Junction-mediating and regulatory protein, or JMY, is a 110 kDa protein that interacts with p300 and has a role in regulating p53 activity. Additionally, JMY is a member of the WASp family of actin nucleators.
References
Proteins | Junction-mediating and regulatory protein | [
"Chemistry"
] | 57 | [
"Biomolecules by chemical classification",
"Protein stubs",
"Biochemistry stubs",
"Molecular biology",
"Proteins"
] |
52,999,366 | https://en.wikipedia.org/wiki/Monoamine%20receptor | A monoamine receptor is a receptor for the monoamine neurotransmitters and/or trace amines, endogenous small-molecule signaling molecules with a monoamine structure. The monoamine receptors are almost all G protein-coupled receptors, with the serotonin 5-HT3 receptor being a notable exception as a ligand-gated ion channel. Monoamine receptors are the biological targets of many drugs; such drugs may be referred to as "monoaminergic".
List of receptors
Monoamine receptors include the following classes:
Adrenergic receptors – bound by epinephrine (adrenaline) and norepinephrine (noradrenaline)
Dopamine receptors – bound by dopamine
Histamine receptors – bound by histamine
Melatonin receptors – bound by melatonin
Serotonin receptors – bound by serotonin (5-HT)
Trace amine-associated receptors – bound by trace amines, thyronamines, monoamine neurotransmitters (TAAR1 only), and trimethylamine (TAAR5 only)
References
Transmembrane receptors | Monoamine receptor | [
"Chemistry"
] | 236 | [
"Transmembrane receptors",
"Signal transduction"
] |
52,999,847 | https://en.wikipedia.org/wiki/Clonophycus | Clonophycus is a genus of fossil microalgae. The type species, C. elegans, was found in the Barney Creek Formation (McArthur Group), of the Middle Proterozoic of Northern Australia. The authors are uncertain if the microalgae are prokaryotic cyanobacteria or eukaryotic green or red algae.
Species
†Clonophycus belium Late Sinian to Early Cambrian
†Clonophycus bellus Late Sinian to Early Cambrian
†Clonophycus biattina Middle Proterozoic to Late Proterozoic - Australia (N.Territory) China(Hupei)
†Clonophycus dissides Late Precambrian
†Clonophycus elegans (type) Middle Proterozoic - Australia
†Clonophycus guizhouensis Late Sinian to Early Cambrian
†Clonophycus inaequimagnus Late Precambrian
†Clonophycus laceyi Proterozoic
†Clonophycus maximus Early Cambrian
†Clonophycus ostiolum Middle Proterozoic
†Clonophycus refringens Middle Proterozoic
†Clonophycus vacus Sinian
†Clonophycus vulgaris Middle Proterozoic
References
External links
Clonophycus at paleobotany.ru
Incertae sedis
Proterozoic Oceania
Proterozoic life | Clonophycus | [
"Biology"
] | 297 | [
"Algae stubs",
"Algae",
"Incertae sedis",
"Taxonomy (biology)"
] |
53,000,969 | https://en.wikipedia.org/wiki/Acetryptine | Acetryptine (INN) (developmental code name W-2965-A), also known as 5-acetyltryptamine (5-AT), is a drug described as an antihypertensive agent which was never marketed. Structurally, acetryptine is a substituted tryptamine, and is closely related to other substituted tryptamines like serotonin (5-hydroxytryptamine). It was developed in the early 1960s. The binding of acetryptine to serotonin receptors does not seem to have been well-investigated, although it was assessed at the 5-HT1A and 5-HT1D receptors and found to bind to them with high affinity. The drug may also act as a monoamine oxidase inhibitor (MAOI); specifically, as an inhibitor of MAO-A.
See also
5-Benzyloxytryptamine
5-Carboxamidotryptamine
5-Ethoxy-DMT
5-Methoxytryptamine
5-Methyltryptamine
5-(Nonyloxy)tryptamine
Azepindole
Indorenate
Metralindole
Pargyline
Pirlindole
Sumatriptan
Tetrindole
References
Antihypertensive agents
Serotonin receptor agonists
Tryptamines
Ketones | Acetryptine | [
"Chemistry"
] | 280 | [
"Ketones",
"Functional groups"
] |
53,001,602 | https://en.wikipedia.org/wiki/List%20of%20countries%20by%20net%20oil%20exports | This is a list of countries by net oil exports in barrels per day based on The World Factbook and other sources. "Net export" refers to the export minus the import. Note that the net export is approximate, since the import and export data are generally not for same year (though year-to-year changes are generally small). Many countries are missing data for either imports or exports, but this generally indicates that the missing number is small.
See also
List of countries by oil imports
List of countries by oil exports
References
Energy-related lists by country
Exports, net
Trade by commodity
List of countries by oil imports
Lists of countries
International trade-related lists | List of countries by net oil exports | [
"Chemistry"
] | 134 | [
"Petroleum",
"Petroleum by country"
] |
53,002,210 | https://en.wikipedia.org/wiki/Bouncing%20ball | The physics of a bouncing ball concerns the physical behaviour of bouncing balls, particularly its motion before, during, and after impact against the surface of another body. Several aspects of a bouncing ball's behaviour serve as an introduction to mechanics in high school or undergraduate level physics courses. However, the exact modelling of the behaviour is complex and of interest in sports engineering.
The motion of a ball is generally described by projectile motion (which can be affected by gravity, drag, the Magnus effect, and buoyancy), while its impact is usually characterized through the coefficient of restitution (which can be affected by the nature of the ball, the nature of the impacting surface, the impact velocity, rotation, and local conditions such as temperature and pressure). To ensure fair play, many sports governing bodies set limits on the bounciness of their ball and forbid tampering with the ball's aerodynamic properties. The bounciness of balls has been a feature of sports as ancient as the Mesoamerican ballgame.
Forces during flight and effect on motion
The motion of a bouncing ball obeys projectile motion. Many forces act on a real ball, namely the gravitational force (FG), the drag force due to air resistance (FD), the Magnus force due to the ball's spin (FM), and the buoyant force (FB). In general, one has to use Newton's second law taking all forces into account to analyze the ball's motion:
where m is the ball's mass. Here, a, v, r represent the ball's acceleration, velocity, and position over time t.
Gravity
The gravitational force is directed downwards and is equal to
where m is the mass of the ball, and g is the gravitational acceleration, which on Earth varies between and . Because the other forces are usually small, the motion is often idealized as being only under the influence of gravity. If only the force of gravity acts on the ball, the mechanical energy will be conserved during its flight. In this idealized case, the equations of motion are given by
where a, v, and r denote the acceleration, velocity, and position of the ball, and v0 and r0 are the initial velocity and position of the ball, respectively.
More specifically, if the ball is bounced at an angle θ with the ground, the motion in the x- and y-axes (representing horizontal and vertical motion, respectively) is described by
The equations imply that the maximum height (H) and range (R) and time of flight (T) of a ball bouncing on a flat surface are given by
Further refinements to the motion of the ball can be made by taking into account air resistance (and related effects such as drag and wind), the Magnus effect, and buoyancy. Because lighter balls accelerate more readily, their motion tends to be affected more by such forces.
Drag
Air flow around the ball can be either laminar or turbulent depending on the Reynolds number (Re), defined as:
where ρ is the density of air, μ the dynamic viscosity of air, D the diameter of the ball, and v the velocity of the ball through air. At a temperature of , and .
If the Reynolds number is very low (Re < 1), the drag force on the ball is described by Stokes' law:
where r is the radius of the ball. This force acts in opposition to the ball's direction (in the direction of ). For most sports balls, however, the Reynolds number will be between 104 and 105 and Stokes' law does not apply. At these higher values of the Reynolds number, the drag force on the ball is instead described by the drag equation:
where Cd is the drag coefficient, and A the cross-sectional area of the ball.
Drag will cause the ball to lose mechanical energy during its flight, and will reduce its range and height, while crosswinds will deflect it from its original path. Both effects have to be taken into account by players in sports such as golf.
Magnus effect
The spin of the ball will affect its trajectory through the Magnus effect. According to the Kutta–Joukowski theorem, for a spinning sphere with an inviscid flow of air, the Magnus force is equal to
where r is the radius of the ball, ω the angular velocity (or spin rate) of the ball, ρ the density of air, and v the velocity of the ball relative to air. This force is directed perpendicular to the motion and perpendicular to the axis of rotation (in the direction of ). The force is directed upwards for backspin and downwards for topspin. In reality, flow is never inviscid, and the Magnus lift is better described by
where ρ is the density of air, CL the lift coefficient, A the cross-sectional area of the ball, and v the velocity of the ball relative to air. The lift coefficient is a complex factor which depends amongst other things on the ratio rω/v, the Reynolds number, and surface roughness. In certain conditions, the lift coefficient can even be negative, changing the direction of the Magnus force (reverse Magnus effect).
In sports like tennis or volleyball, the player can use the Magnus effect to control the ball's trajectory (e.g. via topspin or backspin) during flight. In golf, the effect is responsible for slicing and hooking which are usually a detriment to the golfer, but also helps with increasing the range of a drive and other shots. In baseball, pitchers use the effect to create curveballs and other special pitches.
Ball tampering is often illegal, and is often at the centre of cricket controversies such as the one between England and Pakistan in August 2006. In baseball, the term 'spitball' refers to the illegal coating of the ball with spit or other substances to alter the aerodynamics of the ball.
Buoyancy
Any object immersed in a fluid such as water or air will experience an upwards buoyancy. According to Archimedes' principle, this buoyant force is equal to the weight of the fluid displaced by the object. In the case of a sphere, this force is equal to
The buoyant force is usually small compared to the drag and Magnus forces and can often be neglected. However, in the case of a basketball, the buoyant force can amount to about 1.5% of the ball's weight. Since buoyancy is directed upwards, it will act to increase the range and height of the ball.
Impact
When a ball impacts a surface, the surface recoils and vibrates, as does the ball, creating both sound and heat, and the ball loses kinetic energy. Additionally, the impact can impart some rotation to the ball, transferring some of its translational kinetic energy into rotational kinetic energy. This energy loss is usually characterized (indirectly) through the coefficient of restitution (or COR, denoted e):
where vf and vi are the final and initial velocities of the ball, and uf and ui are the final and initial velocities of the impacting surface, respectively. In the specific case where a ball impacts on an immovable surface, the COR simplifies to
For a ball dropped against a floor, the COR will therefore vary between 0 (no bounce, total loss of energy) and 1 (perfectly bouncy, no energy loss). A COR value below 0 or above 1 is theoretically possible, but would indicate that the ball went through the surface (), or that the surface was not "relaxed" when the ball impacted it (), like in the case of a ball landing on spring-loaded platform.
To analyze the vertical and horizontal components of the motion, the COR is sometimes split up into a normal COR (ey), and tangential COR (ex), defined as
where r and ω denote the radius and angular velocity of the ball, while R and Ω denote the radius and angular velocity the impacting surface (such as a baseball bat). In particular rω is the tangential velocity of the ball's surface, while RΩ is the tangential velocity of the impacting surface. These are especially of interest when the ball impacts the surface at an oblique angle, or when rotation is involved.
For a straight drop on the ground with no rotation, with only the force of gravity acting on the ball, the COR can be related to several other quantities by:
Here, K and U denote the kinetic and potential energy of the ball, H is the maximum height of the ball, and T is the time of flight of the ball. The 'i' and 'f' subscript refer to the initial (before impact) and final (after impact) states of the ball. Likewise, the energy loss at impact can be related to the COR by
The COR of a ball can be affected by several things, mainly
the nature of the impacting surface (e.g. grass, concrete, wire mesh)
the material of the ball (e.g. leather, rubber, plastic)
the pressure inside the ball (if hollow)
the amount of rotation induced in the ball at impact
the impact velocity
External conditions such as temperature can change the properties of the impacting surface or of the ball, making them either more flexible or more rigid. This will, in turn, affect the COR. In general, the ball will deform more at higher impact velocities and will accordingly lose more of its energy, decreasing its COR.
Spin and angle of impact
Upon impacting the ground, some translational kinetic energy can be converted to rotational kinetic energy and vice versa depending on the ball's impact angle and angular velocity. If the ball moves horizontally at impact, friction will have a "translational" component in the direction opposite to the ball's motion. In the figure, the ball is moving to the right, and thus it will have a translational component of friction pushing the ball to the left. Additionally, if the ball is spinning at impact, friction will have a "rotational" component in the direction opposite to the ball's rotation. On the figure, the ball is spinning clockwise, and the point impacting the ground is moving to the left with respect to the ball's center of mass. The rotational component of friction is therefore pushing the ball to the right. Unlike the normal force and the force of gravity, these frictional forces will exert a torque on the ball, and change its angular velocity (ω).
Three situations can arise:
If a ball is propelled forward with backspin, the translational and rotational friction will act in the same directions. The ball's angular velocity will be reduced after impact, as will its horizontal velocity, and the ball is propelled upwards, possibly even exceeding its original height. It is also possible for the ball to start spinning in the opposite direction, and even bounce backwards.
If a ball is propelled forward with topspin, the translational and rotational friction act will act in opposite directions. What exactly happens depends on which of the two components dominate.
If the ball is spinning much more rapidly than it was moving, rotational friction will dominate. The ball's angular velocity will be reduced after impact, but its horizontal velocity will be increased. The ball will be propelled forward but will not exceed its original height, and will keep spinning in the same direction.
If the ball is moving much more rapidly than it was spinning, translational friction will dominate. The ball's angular velocity will be increased after impact, but its horizontal velocity will be decreased. The ball will not exceed its original height and will keep spinning in the same direction.
If the surface is inclined by some amount θ, the entire diagram would be rotated by θ, but the force of gravity would remain pointing downwards (forming an angle θ with the surface). Gravity would then have a component parallel to the surface, which would contribute to friction, and thus contribute to rotation.
In racquet sports such as table tennis or racquetball, skilled players will use spin (including sidespin) to suddenly alter the ball's direction when it impacts surface, such as the ground or their opponent's racquet. Similarly, in cricket, there are various methods of spin bowling that can make the ball deviate significantly off the pitch.
Non-spherical balls
The bounce of an oval-shaped ball (such as those used in gridiron football or rugby football) is in general much less predictable than the bounce of a spherical ball. Depending on the ball's alignment at impact, the normal force can act ahead or behind the centre of mass of the ball, and friction from the ground will depend on the alignment of the ball, as well as its rotation, spin, and impact velocity. Where the forces act with respect to the centre of mass of the ball changes as the ball rolls on the ground, and all forces can exert a torque on the ball, including the normal force and the force of gravity. This can cause the ball to bounce forward, bounce back, or sideways. Because it is possible to transfer some rotational kinetic energy into translational kinetic energy, it is even possible for the COR to be greater than 1, or for the forward velocity of the ball to increase upon impact.
Multiple stacked balls
A popular demonstration involves the bounce of multiple stacked balls. If a tennis ball is stacked on top of a basketball, and the two of them are dropped at the same time, the tennis ball will bounce much higher than it would have if dropped on its own, even exceeding its original release height. The result is surprising as it apparently violates conservation of energy. However, upon closer inspection, the basketball does not bounce as high as it would have if the tennis ball had not been on top of it, and transferred some of its energy into the tennis ball, propelling it to a greater height.
The usual explanation involves considering two separate impacts: the basketball impacting with the floor, and then the basketball impacting with the tennis ball. Assuming perfectly elastic collisions, the basketball impacting the floor at 1 m/s would rebound at 1 m/s. The tennis ball going at 1 m/s would then have a relative impact velocity of 2 m/s, which means it would rebound at 2 m/s relative to the basketball, or 3 m/s relative to the floor, and triple its rebound velocity compared to impacting the floor on its own. This implies that the ball would bounce to 9 times its original height.
In reality, due to inelastic collisions, the tennis ball will increase its velocity and rebound height by a smaller factor, but still will bounce faster and higher than it would have on its own.
While the assumptions of separate impacts is not actually valid (the balls remain in close contact with each other during most of the impact), this model will nonetheless reproduce experimental results with good agreement, and is often used to understand more complex phenomena such as the core collapse of supernovae, or gravitational slingshot manoeuvres.
Sport regulations
Several sports governing bodies regulate the bounciness of a ball through various ways, some direct, some indirect.
AFL: Regulates the gauge pressure of the football to be between and .
FIBA: Regulates the gauge pressure so the basketball bounces between 1035 mm and 1085 mm (bottom of the ball) when it is dropped from a height of 1800 mm (bottom of the ball). This corresponds to a COR between 0.758 and 0.776.
FIFA: Regulates the gauge pressure of the soccer ball to be between of and at sea level (61 to 111 kPa).
FIVB: Regulates the gauge pressure of the volleyball to be between to (29.4 to 31.9 kPa) for indoor volleyball, and to (17.2 to 22.1 kPa) for beach volleyball.
ITF: Regulates the height of the tennis ball bounce when dropped on a "smooth, rigid and horizontal block of high mass". Different types of ball are allowed for different types of surfaces. When dropped from a height of , the bounce must be for Type 1 balls, for Type 2 and Type 3 balls, and for High Altitude balls. This roughly corresponds to a COR of 0.735–0.775 (Type 1 ball), 0.728–0.762 (Type 2 & 3 balls), and 0.693–0.728 (High Altitude balls) when dropped on the testing surface.
ITTF: Regulates the playing surface so that the table tennis ball bounces approximately 23 cm when dropped from a height of 30 cm. This roughly corresponds to a COR of about 0.876 against the playing surface.
NBA: Regulates the gauge pressure of the basketball to be between 7.5 and 8.5 psi (51.7 to 58.6 kPa).
NFL: Regulates the gauge pressure of the American football to be between 12.5 and 13.5 psi (86 to 93 kPa).
R&A/USGA: Limits the COR of the golf ball directly, which should not exceed 0.83 against a golf club.
The pressure of an American football was at the center of the deflategate controversy. Some sports do not regulate the bouncing properties of balls directly, but instead specify a construction method. In baseball, the introduction of a cork-based ball helped to end the dead-ball era and trigger the live-ball era.
See also
Bouncy ball
List of ball games
Quantum bouncing ball
Notes
References
Further reading
Balls
Sports rules and regulations
Classical mechanics
Kinematics
Dynamical systems
Motion (physics) | Bouncing ball | [
"Physics",
"Mathematics",
"Technology"
] | 3,618 | [
"Machines",
"Kinematics",
"Physical phenomena",
"Classical mechanics",
"Physical systems",
"Motion (physics)",
"Space",
"Mechanics",
"Spacetime",
"Dynamical systems"
] |
53,003,796 | https://en.wikipedia.org/wiki/OTE%20Pathfinder | The OTE Pathfinder (for Optical Telescope Element Pathfinder), or James Webb Space Telescope Pathfinder, is a technology demonstrator and test article for the James Webb Space Telescope. It is a non-flight replica of the actual backplane, but only includes the center section, not the two "wings" on the side that extend and have additional segments on the actual JWST. It has been used for various tests and has some different configurations, but some of the major tests have been practicing installing mirror segments with non-flight hardware as well as thermal tests. The Pathfinder has also been tested in conjunction with flight hardware including the Aft Optics System. One of the goals and uses of the pathfinder is risk reduction for JWST program. The pathfinder allows practicing integration and testing procedures, and for risk mitigation With the Pathfinder it was possible to test phasing two mirrors together and also to do tests with the Aft Optical System. The OTE Pathfinder was part of the plan for integration and testing of JWST, and in particular supported the Optical Telescope Element (primary mirror, backplane, etc.).
The OTE pathfinder uses two additional mirror segments and an additional secondary mirror, and puts together various structures to allow testing of various aspects of the section, including Ground Support Equipment. This supports the GSE's use on the JWST itself later on, and allows testing of mirror integration. OTE pathfinder has 12 rather than 18 cells compared to the full telescope, but it does include a test of the backplane structure. The pathfinder allowed practicing installing mirror segments with a non-flight mirror and non-flight backplane. Mirror installation is a task that necessitated practice due to the high-precision required.
The Pathfinder backplane was completed in 2011. Three tests planned for the OTE Pathfinder were Optical Ground Support Equipment 1 (OGSE1), Optical Ground Support Equipment 2 (OGSE2), and Thermal Pathfinder.
The Pathfinder was used with the Beam Image Analyzer (BIA) and another important related device is the AOS Source Plate Assembly (ASPA). ASPA provides infrared sources for doing optical testing.
California
The flight-replica backplane was assembled in Redondo Beach, California, at the NASA contractor Northrop Grumman facility there. The flight backplane has two wings and a center section, whereas the pathfinder just as center section. The backplane was transported across country (see Continental United States) in a C-5 Galaxy transport aircraft to Joint Base Andrews, and to GSC by road. The section is contained with the Space Telescope Transporter for Air Road and Sea (STTARS), which was designed for the project. This facilitates hauling items around the country for different tests or assembly for the JWST project.
The backplane is constructed out of graphite composite, titanium, and invar. Invar is an iron-nickel alloy with a low coefficient of thermal expansion (CTE or α), which means it does not significantly change size during temperature changes. One of the important features of the backplane is that it is thermally stable at low temperatures, because it is holding the main mirror, it must change size less than one-ten-thousandth of a human hair (32 nm) at . Another test of the backplane design was the Backplane Structure Test Article, which was a one sixth portion of the full backplane.
Maryland (Goddard Spaceflight Center)
In 2014 the pathfinder was transported from California to Maryland. In Maryland it was used for practicing mirror installation at Goddard Space Flight Center. It arrived at GSC in Maryland in July 2014. Mirror segments were installed on the Pathfinder, which allowed the procedure to be practiced.
At Goddard Spaceflight Center the two spare main mirror segments and a spare secondary mirror were installed on the pathfinder. The full James Webb Space Telescope main mirror has 18 segments (primary). It was considered to use silver, however gold is more durable than silver as a coating even though it is used for reflecting down to 400 nm wavelength light; JWST is primarily for 800 nm to 29000 nm.
The Pathfinder weighed about after the mirrors were installed.
Texas (Johnson Space Center)
After the work done in Maryland at Goddard, the pathfinder was taken to Johnson Space Center in Texas, for cold environment testing. The Pathfinder was delivered to JSC by early February 2015. In preparation for its arrival, in 2014 Optical Ground Support Equipment was installed at the cryogenic test chamber at Johnson Space Center. The ground support equipment was tested during the OGSE-1 in Chamber A at JSC, after which the Aft Optical Subsystem and Beam analyzer were installed and tested in OGSE-2. The first test was completed by June 2015, and the second test was completed by November 2015. The third major test, which involves even more modifications to pathfinder is called Thermal Pathfinder. During the optical tests the mirrors had to be "phased" or aligned to a distance less than the wavelength of light, thousands of times smaller than the thickness of a human hair at a temperature hundreds of degree below zero.
By the end of October 2015 the second round of testing with JWST was completed. The flight Aft Optics System was tested with the Pathfinder, and it was delivered for testing in May 2015. The Aft Optics System is part of the Optical Telescope Element in the flight telescope.
In 2016 the pathfinder was used for the Pathfinder Thermal Test at Johnson Space Center in Texas. At this time it had two spare flight-rated beryllium mirrors (one gold-coated) and ten non-flight gold-coated aluminum test segments functioning as thermal simulators. In 2016 the pathfinder underwent thermal and vacuum tests that the actual JWST was planned to also go through in 2017. The test chamber was originally built to test Apollo program hardware, but was refurbished for testing in the JWST program. The thermal test will take similar hardware on cool down time line, which allows heat flow to be studied. The flight JWST primary mirror is designed to be cooled down to for operation, and the thermal tests on the pathfinder support this goal. The pathfinder had to be modified for the thermal tests, including the thermal simulators to stand in for the mirrors, but also insulation. There is also an Aft Optical Subsystem Geometry Simulator and an ISIM Electronics Compartment Simulator. The thermal test also demonstrates the Space Vehicle Thermal Simulator (SVTS) and the Deep Space Edge Radiation Sinks (DSERS).
Components
As a test article the exact configuration has varied somewhat as it undergoes various tests.
Components have included:
Test version of the backplane (full-size engineering model)
Two spare beryllium mirror segments
Spare secondary mirror
Ten gold-coated aluminum thermal simulator segments
See also
Thermal radiation
Thermal conductivity
References
External links
Use of a pathfinder optical telescope element for James Webb Space Telescope risk mitigation
James Webb Space Telescope Thermal Pathfinder Test Development
Successful Completion of the JWST OGSE2 Cryogenic Test at JSC Chamber-A while Managing Numerous Challenges
James Webb Space Telescope
Technology demonstrations | OTE Pathfinder | [
"Astronomy"
] | 1,459 | [
"Space telescopes",
"James Webb Space Telescope"
] |
53,004,829 | https://en.wikipedia.org/wiki/ERICH2 | Glutamate Rich Protein 2 is a protein in humans encoded by the gene ERICH2. This protein is expressed heavily in male tissues specifically in the testes, and proteins are specifically found in the nucleoli fibrillar center and the vesicles of these testicular cells. The protein has multiple protein interactions which indicate that it may play a role in histone modification and proper histone functioning.
Gene
ERICH2 is located on human Chromosome 2, at 2q31.1. It contains 10 distinct exons. The gene itself is 28,930 base pairs long and is flanked by the EIF2S2P4 and GAD1 genes. There are no known paralogs of the ERICH2 gene.
mRNA
ERICH2 transcription produces three validated distinct mRNA variants. The longest transcript variant is 1,388 base pairs in length, 1,311 of which are coding. The second variant differs from the first in its 5' UTR. It also has coding sequence differences and a distinct N-terminus compared to variant 1. Variant 3 lacks several exons, has a distinct 3' UTR and C- terminus coding region. This variant is also shorter than the other two at 1,063 base pairs.
Protein
The ERICH2 protein is 436 amino acids in length, and has a molecular weight of approximately 48,000 kD, with an isoelectric point of approximately 5. The protein is determined to be rich in the amino acid proline and low in tyrosine and glycine.
Motifs and domains
Two known motifs were found in the human ERICH2 protein. The KKNT motif functions in cAMP- and cGMP- dependent protein phosphorylation, this protein motif was found only in primates. There is also a FGRR motif conserved in mammals that is defined as an amidation site. Finally the ERICH2 protein contains the PHA03247 domain that is 32 amino acids long. This domain is not generally conserved through orthologs and the function is unknown. It is present in the proteins that make up the herpes virion.
Structure and localization
Secondary structure prediction shows one alpha helix and one beta strand formation. The alpha helix encompasses the entire conserved section as seen in the cartoon of the ERICH2 protein. The beta strand is predicted 12 amino acids down from the amidation site and encompasses 4 amino acids. Four nuclear localization signals were found in the protein, two pat4 signals and two pat7 signals, their locations are shown in the cartoon. It is predicted in the 78th percent that the protein resides in the nucleus.
Expression
ERICH2 is not ubiquitously expressed. It however, has been shown to be expressed narrowly in the choroid plexus of a developing fetus and in the testes of adults. Lung and female tissue expression were also present but expression was greatly decreased. Proteins are specifically located in the nucleoli fibrillar center and the vesicles within cells.
Regulation of expression
Many phosphorylation sites are predicted for the ERICH2 protein. None are predicted on tyrosines only on serines and the threonines. There is also a predicted acetylation site at the N-terminus of the protein, specifically it is predicted on the third amino acid. Many SOX/SRY-sex/testis determining and related HMG box factor transcription factors and estrogen related transcription factors are predicted to bind and regulate transcription of ERICH2.
Function
Interacting proteins
ERICH2 interacts with proteins in the H2A family. The H2A proteins specifically play a role in the octamer structure of histone. ERICH2 is specifically known to interact with the H2AFY protein, which plays a key role in the stable X chromosome inactivation and can function by replacing a normal H2A in certain nucleosomes and thus repressing transcription.
ERICH2 is also known to interact with the protein SDCB1 which functions in vesicle trafficking and the regulation of growth and proliferation of certain cancer cells.
The IWS1 protein also interacts with ERICH2. This protein functions as a transcription factor and plays a key role in defining the composition of the RNA polymerase II elongation complex. This complex then plays a role in histone modification and proper splicing.
Two-hybrid assays and other protein interaction methods have shown an interaction with the PSORS1C2 protein, but the function of this protein remains unknown.
Homology
No paralogs for the ERICH2 protein are known. ERICH2 has 124 known orthologs spanning multiple taxa.
References
Proteins | ERICH2 | [
"Chemistry"
] | 940 | [
"Proteins",
"Biomolecules by chemical classification",
"Molecular biology"
] |
57,631,467 | https://en.wikipedia.org/wiki/%CE%91-O | α-O (alpha-oxygen) is a reactive oxygen species formed from an oxygen-atom abstraction (OAT) from nitrous oxide (N2O) by alpha-iron (α-Fe) catalysts. The latter is defined as a high spin (S=2) divalent iron(II) ion in a constrained square planar coordination with an accessible axial coordination position. The stabilization of α-O requires structural strain on the equatorial ligand field to maintain the reactive oxygen atom in the axial position and it is this forced geometry, similar to the 'entatic state' known in metalloproteins, that lies at the basis of its reactivity in inert C-H bond activation.
The alpha-oxygen site was first discovered and named in 1990 by researchers from the Boreskov Institute of Catalysis in the ZSM-5 zeolite, and was later described in detail by researchers from Stanford University and KU Leuven in the beta zeolite.
See also
Carbon–hydrogen bond activation
Catalysis
References
Reactive oxygen species
Reactive intermediates | Α-O | [
"Chemistry"
] | 221 | [
"Organic compounds",
"Reactive intermediates",
"Physical organic chemistry"
] |
57,631,953 | https://en.wikipedia.org/wiki/List%20of%20business%20and%20financial%20search%20engines | This is a list of vertical search engines focusing on business and financial content.
Defunct Business Search Engines
Business.com
References
External links
IFACnet
Lexis Nexis
Domain-specific search engines
Information retrieval systems | List of business and financial search engines | [
"Technology"
] | 43 | [
"Information technology",
"Information retrieval systems"
] |
57,632,169 | https://en.wikipedia.org/wiki/H3K9me2 | H3K9me2 is an epigenetic modification to the DNA packaging protein Histone H3. It is a mark that indicates the di-methylation at the 9th lysine residue of the histone H3 protein. H3K9me2 is strongly associated with transcriptional repression. H3K9me2 levels are higher at silent compared to active genes in a 10kb region surrounding the transcriptional start site. H3K9me2 represses gene expression both passively, by prohibiting acetylation as therefore binding of RNA polymerase or its regulatory factors, and actively, by recruiting transcriptional repressors. H3K9me2 has also been found in megabase blocks, termed Large Organised Chromatin K9 domains (LOCKS), which are primarily located within gene-sparse regions but also encompass genic and intergenic intervals. Its synthesis is catalyzed by G9a, G9a-like protein, and PRDM2. H3K9me2 can be removed by a wide range of histone lysine demethylases (KDMs) including KDM1, KDM3, KDM4 and KDM7 family members. H3K9me2 is important for various biological processes including cell lineage commitment, the reprogramming of somatic cells to induced pluripotent stem cells, regulation of the inflammatory response, and addiction to drug use.
Nomenclature
H3K9me2 indicates dimethylation of lysine 9 on histone H3 protein subunit:
Lysine methylation
This diagram shows the progressive methylation of a lysine residue. The di-methylation (third from left) denotes the methylation presentpresent in H3K9me2.
Understanding histone modifications
The genomic DNA of eukaryotic cells is wrapped around special protein molecules known as histones. The complexes formed by the looping of the DNA are known as chromatin. The basic structural unit of chromatin is the nucleosome: this consists of the core octamer of histones (H2A, H2B, H3 and H4) as well as a linker histone and about 180 base pairs of DNA. These core histones are rich in lysine and arginine residues. The carboxyl (C) terminal end of these histones contribute to histone-histone interactions, as well as histone-DNA interactions. The amino (N) terminal charged tails are the site of the post-translational modifications, such as the one seen in H3K9me2.
Epigenetic implications
The post-translational modification of histone tails by either histone modifying complexes or chromatin remodelling complexes are interpreted by the cell and lead to complex, combinatorial transcriptional output. It is thought that a histone code dictates the expression of genes by a complex interaction between the histones in a particular region. The current understanding and interpretation of histones comes from two large scale projects: ENCODE and the Epigenomic roadmap. The purpose of the epigenomic study was to investigate epigenetic changes across the entire genome. This led to chromatin states which define genomic regions by grouping the interactions of different proteins and/or histone modifications together.
Chromatin states were investigated in Drosophila cells by looking at the binding location of proteins in the genome. Use of chromatin immunoprecipitation (ChIP)-sequencing revealed regions in the genome characterised by different banding. Different developmental stages were profiled in Drosophila as well, an emphasis was placed on histone modification relevance. A look in to the data obtained led to the definition of chromatin states based on histone modifications. Certain modifications were mapped and enrichment was seen to localize in certain genomic regions. Five core histone modifications were found with each respective one being linked to various cell functions.
H3K4me3-promoters
H3K4me1- primed enhancers
H3K36me3-gene bodies
H3K27me3-polycomb repression
H3K9me3-heterochromatin
H3K9me2-facultative heterochromatin
The human genome was annotated with chromatin states. These annotated states can be used as new ways to annotate a genome independently of the underlying genome sequence. This independence from the DNA sequence enforces the epigenetic nature of histone modifications. Chromatin states are also useful in identifying regulatory elements that have no defined sequence, such as enhancers. This additional level of annotation allows for a deeper understanding of cell specific gene regulation.
Clinical significance
Addiction
Chronic addictive drug exposure results in ΔFosB-mediated repression of G9a and reduced H3K9 dimethylation in the nucleus accumbens, which in turn causes dendritic arborization, altered synaptic protein expression, and increased drug seeking behavior. In contrast, accumbal G9a hyperexpression results in markedly increased H3K9 dimethylation and blocks the induction of this neural and behavioral plasticity by chronic drug use, which occurs via H3K9me2-mediated repression of transcription factors for ΔFosB and H3K9me2-mediated repression of various ΔFosB transcriptional targets (e.g., CDK5). Due to the involvement of H3K9me2 in these feedback loops and the central pathophysiological role of ΔFosB overexpression as the mechanistic trigger for addiction, the reduction of accumbal H3K9me2 following repeated drug exposure directly mediates the development of drug addictions.
Friedreich's ataxia
R-loop's are found with H3K9me2 mark at FXN in Friedreich's ataxia cells.
Cardiovascular disease
H3K9me2 is present at a subset of cardiovascular disease-associated gene promoters in vascular smooth muscle cells to block binding of NFκB and AP-1 (activator protein-1) transcription factors. Reduced levels of H3K9me2 have been observed in vascular smooth muscle cells from human atherosclerotic lesions compared to healthy aortic tissue in patients. Vascular smooth muscle cells from diabetic patients display reduced levels of H3K9me2 compared to non-diabetic controls; it has therefore been suggested that dysregulation of H3K9me2 might underlie the vascular complications associated with diabetes. Loss of H3K9me2 in vascular smooth muscle cells exacerbates upregulation of a subset of cardiovascular disease-associated genes in vascular disease models.
Methods
Histone modifications, including H3K9me2, can be detected using a variety of methods:
Chromatin Immunoprecipitation Sequencing (ChIP-sequencing) measures the amount of DNA enrichment once bound to a targeted protein and immunoprecipitated. It results in good optimization and is used in vivo to reveal DNA-protein binding occurring in cells. ChIP-Seq can be used to identify and quantify various DNA fragments for different histone modifications along a genomic region.
CUT&RUN(Cleavage Under Targets and Release Using Nuclease). In CUT&RUN, targeted DNA-protein complexes are isolated directly from the cell nucleus rather than following a precipitation step. To perform CUT&RUN, a specific antibody to the DNA-binding protein of interest and ProtA-MNase is added to permeabilised cells. MNase is tethered to the protein of interest through the ProtA-antibody interaction and MNase cleaves the surrounding, unprotected DNA to release protein-DNA complexes, which can then be isolated and sequenced. CUT&RUN is reported to give a much higher signal to noise ratio compared to traditional ChIP. CUT&RUN therefore requires one tenth of the sequencing depth of ChIP and permits genomic mapping of histone modifications and transcription factors using extremely low cell numbers.
Modification-specific intracellular antibody probes. Sensitive fluorescent genetically encoded histone modification-specific intracellular antibody (mintbody) probes can be used to monitor changes in histone modifications in living cells.
See also
Histone methylation
Histone methyltransferase
Methyllysine
References
Δ
Epigenetics
Post-translational modification | H3K9me2 | [
"Chemistry"
] | 1,751 | [
"Post-translational modification",
"Gene expression",
"Biochemical reactions"
] |
57,633,087 | https://en.wikipedia.org/wiki/Compact%20object%20%28mathematics%29 | In mathematics, compact objects, also referred to as finitely presented objects, or objects of finite presentation, are objects in a category satisfying a certain finiteness condition.
Definition
An object X in a category C which admits all filtered colimits (also known as direct limits) is called compact if the functor
commutes with filtered colimits, i.e., if the natural map
is a bijection for any filtered system of objects in C. Since elements in the filtered colimit at the left are represented by maps , for some i, the surjectivity of the above map amounts to requiring that a map factors over some .
The terminology is motivated by an example arising from topology mentioned below. Several authors also use a terminology which is more closely related to algebraic categories: use the terminology finitely presented object instead of compact object. call these the objects of finite presentation.
Compactness in ∞-categories
The same definition also applies if C is an ∞-category, provided that the above set of morphisms gets replaced by the mapping space in C (and the filtered colimits are understood in the ∞-categorical sense, sometimes also referred to as filtered homotopy colimits).
Compactness in triangulated categories
For a triangulated category C which admits all coproducts, defines an object to be compact if
commutes with coproducts. The relation of this notion and the above is as follows: suppose C arises as the homotopy category of a stable ∞-category admitting all filtered colimits. (This condition is widely satisfied, but not automatic.) Then an object in C is compact in Neeman's sense if and only if it is compact in the ∞-categorical sense. The reason is that in a stable ∞-category, always commutes with finite colimits since these are limits. Then, one uses a presentation of filtered colimits as a coequalizer (which is a finite colimit) of an infinite coproduct.
Examples
The compact objects in the category of sets are precisely the finite sets.
For a ring R, the compact objects in the category of R-modules are precisely the finitely presented R-modules. In particular, if R is a field, then compact objects are finite-dimensional vector spaces.
Similar results hold for any category of algebraic structures given by operations on a set obeying equational laws. Such categories, called varieties, can be studied systematically using Lawvere theories. For any Lawvere theory T, there is a category Mod(T) of models of T, and the compact objects in Mod(T) are precisely the finitely presented models. For example: suppose T is the theory of groups. Then Mod(T) is the category of groups, and the compact objects in Mod(T) are the finitely presented groups.
The compact objects in the derived category of R-modules are precisely the perfect complexes.
Compact topological spaces are not the compact objects in the category of topological spaces. Instead these are precisely the finite sets endowed with the discrete topology. The link between compactness in topology and the above categorical notion of compactness is as follows: for a fixed topological space , there is the category whose objects are the open subsets of (and inclusions as morphisms). Then, is a compact topological space if and only if is compact as an object in .
If is any category, the category of presheaves (i.e., the category of functors from to sets) has all colimits. The original category is connected to by the Yoneda embedding . For any object of , is a compact object (of ).
In a similar vein, any category can be regarded as a full subcategory of the category of ind-objects in . Regarded as an object of this larger category, any object of is compact. In fact, the compact objects of are precisely the objects of (or, more precisely, their images in ).
Non-examples
Derived category of sheaves of Abelian groups on a noncompact X
In the unbounded derived category of sheaves of Abelian groups for a non-compact topological space , it is generally not a compactly generated category. Some evidence for this can be found by considering an open cover (which can never be refined to a finite subcover using the non-compactness of ) and taking a mapfor some . Then, for this map to lift to an elementit would have to factor through some , which is not guaranteed. Proving this requires showing that any compact object has support in some compact subset of , and then showing this subset must be empty.
Derived category of quasi-coherent sheaves on an Artin stack
For algebraic stacks over positive characteristic, the unbounded derived category of quasi-coherent sheaves is in general not compactly generated, even if is quasi-compact and quasi-separated. In fact, for the algebraic stack , there are no compact objects other than the zero object. This observation can be generalized to the following theorem: if the stack has a stabilizer group such that
is defined over a field of positive characteristic
has a subgroup isomorphic to
then the only compact object in is the zero object. In particular, the category is not compactly generated.
This theorem applies, for example, to by means of the embedding sending a point to the identity matrix plus at the -th column in the first row.
Compactly generated categories
In most categories, the condition of being compact is quite strong, so that most objects are not compact. A category is compactly generated if any object can be expressed as a filtered colimit of compact objects in . For example, any vector space V is the filtered colimit of its finite-dimensional (i.e., compact) subspaces. Hence the category of vector spaces (over a fixed field) is compactly generated.
Categories which are compactly generated and also admit all colimits are called accessible categories.
Relation to dualizable objects
For categories C with a well-behaved tensor product (more formally, C is required to be a monoidal category), there is another condition imposing some kind of finiteness, namely the condition that an object is dualizable. If the monoidal unit in C is compact, then any dualizable object is compact as well. For example, R is compact as an R-module, so this observation can be applied. Indeed, in the category of R-modules the dualizable objects are the finitely presented projective modules, which are in particular compact. In the context of ∞-categories, dualizable and compact objects tend to be more closely linked, for example in the ∞-category of complexes of R-modules, compact and dualizable objects agree. This and more general example where dualizable and compact objects agree are discussed in .
References
Category theory | Compact object (mathematics) | [
"Mathematics"
] | 1,415 | [
"Functions and mappings",
"Mathematical structures",
"Mathematical objects",
"Fields of abstract algebra",
"Mathematical relations",
"Category theory"
] |
57,634,074 | https://en.wikipedia.org/wiki/Lori%20Passmore | Lori Anne Passmore is a Canadian/British cryo electron microscopist and structural biologist who works at the Medical Research Council (MRC) Laboratory of Molecular Biology (LMB) at the University of Cambridge. She is known for her work on multiprotein complexes involved in gene expression and development of new supports for cryo-EM.
Education
Lori Passmore graduated from the University of British Columbia, Canada in 1999. She obtained a PhD in 2003 from University of London for research supervised by David Barford at the Institute of Cancer Research. She performed in vitro biochemical characterisation of the activity of the anaphase-promoting complex (APC) and used cryo-EM to study the APC structure.
Career and research
Passmore worked as a postdoctoral researcher at the MRC-LMB. She worked with Venki Ramakrishnan and Richard Henderson, using cryo-EM to determine the structure of the eukaryotic ribosome bound to initiation factors. Passmore became a group leader at the MRC-LMB in 2009. Her group uses in vitro reconstitution, biochemical assays and cryo-EM to understand the function of multiprotein complexes that regulate gene expression at the level of mRNA. Her group has developed new sample grids for cryo-EM that reduce specimen movement during imaging. In collaboration with Ketan J. Patel, Passmore is also actively studying the molecular mechanisms underlying Fanconi anemia.
Grants, awards and honours
2005 Beit Memorial Fellowship for Medical Research
2009 Fellow of Clare Hall, Cambridge
2010 European Research Council (ERC) starting grant
2015 EMBO Young Investigator Program
2016 Suffrage Science award
2017 ERC consolidator grant
2018 Member, European Molecular Biology Organisation (EMBO)
2023 Elected Fellow of the Royal Society
References
Year of birth missing (living people)
Living people
Microscopists
University of British Columbia alumni
Members of the European Molecular Biology Organization
Fellows of the Royal Society | Lori Passmore | [
"Chemistry"
] | 400 | [
"Microscopists",
"Microscopy"
] |
57,636,367 | https://en.wikipedia.org/wiki/Butyrolactol%20A | Butyrolactol A is an organic chemical compound of interest for its potential use as an antifungal antibiotic.
One of a number of potentially useful substances derived from the bacteria Streptomyces rochei, it demonstrates broad antimicrobial activity against fungi, including Candida albicans. Butyrolactol A is a polyketide featuring a tert-butyl group linked to a long hydrophobic carbon chain followed by 8 polyol groups. Research has shown that, using isotopic labeling of media and spectroscopic techniques to identify precursor products which are eventually incorporated into the final product, it can be created via a biosynthetic pathway. Further analysis of gene clusters encoding for biosynthetic enzymes confirmed the presence of polyketide synthesizing genes that are involved with the aforementioned pathways for this molecule.
Biosynthesis
Acetate pathway
The long carbon chain contained in Butyrolactol A was determined to originate from the acetate pathway by carbon-14 labeling acetate, the two carbon precursor for polyketide synthase. The presence of PKS genes from the Streptomyces family further confirmed the mechanism of acetyl-group based chain elongation. Carbons 1-8 were confirmed to originate from glycolytic pathway intermediate hydroxymalonyl-ACP (Figure). This is supported by 13C labeling, where 13C-13C couplets were present for the aforementioned carbons, as well as gene sequencing, which found genes coding for enzymes involved in hydroxymalonyl-ACP formation in zwittermicin biosynthesis.
tert-Butyl group
The tert-butyl functional group is a unique moiety in this compound: two of the three carbons were found to originate from the amino acid valine, which contains an isopropyl alkyl side chain. This was determined by deuteration of valine supplied in the media, where mass spectroscopy identified mass/charge ratio reflecting the replacement of 8 hydrogens with deuterium in valine. The final alkyl group in the tert-butyl group was found to be from methionine, likely from SAM. The order in which these precursor units are synthesized has not been confirmed.
References
Polyketides
Polyols
Lactones
Dienes
Tert-butyl compounds | Butyrolactol A | [
"Chemistry"
] | 492 | [
"Biomolecules by chemical classification",
"Natural products",
"Polyketides"
] |
57,637,484 | https://en.wikipedia.org/wiki/Maunakea%20Spectroscopic%20Explorer | The Maunakea Spectroscopic Explorer (MSE) is a collaborative project by a new and enlarged partnership to revitalize the Canada-France-Hawai‘i Telescope (CFHT) observatory through replacing the existing 1970-vintage optical telescope with a modern segmented-mirror telescope and dedicated science instrumentation, while substantially re-using the existing Maunakea summit building and facility. At the highest level the objectives of MSE are to enhance scientific research and education for the partner communities. MSE will use an 11.25 meter aperture telescope and dedicated multiobject fibre spectroscopy instrumentation to perform survey science observations, collecting spectra from more than 4,000 astronomical targets simultaneously.
The project completed a conceptual design in early 2018. The project schedule anticipates receiving permission in 2021 to proceed to final design and construction phases, leading to a start of science commissioning in 2029.
Background
Partnership and funding
The MSE project initially took shape through a feasibility study led by the National Research Council of Canada, which showed the strength of the science case for a large aperture dedicated multiobject spectroscopic facility, as well as the technical feasibility of such a facility as an upgrade to CFHT. In 2014, the CFHT established a project office in Waimea HI, to lead and develop the project through to the start of construction. The MSE participants in 2018 consists of national-level or state-level organizations in Canada, France, Hawai‘i, Australia, China and India, with CFHT Corp as the executive agency for the project. University groups in Spain also played a key design role in earlier phases of the project. The project is governed by a Management Group of members from each of the participants. The project design work is funded through cash managed by the Management Group and disbursed by CFHT Corp, as well as through in-kind work by most of the participants.
Construction approval process
Lead documents in the management of the Maunakea lands are the Mauna Kea Science Reserve Master Plan (June 2000) and the Mauna Kea Comprehensive Management Plan (2009 and 2010). The Master Plan explicitly recognizes CFHT as one of the summit sites that will be redeveloped, while the Comprehensive Management Plan prescribes the development and approval process. Although planned changes for MSE are of smaller impact than those categorized as “redevelopment” in the Master Plan and the state's Administrative Rules, MSE is subject to the approval processes that is defined in these documents and managed by Hawai‘i's Department of Land and Natural Resources (DLNR).
CFHT occupies the a site on Maunakea under a sublease to General Lease S-4191 between the State of Hawai‘i and the University of Hawai‘i (UH). The General Lease confers upon UH the rights and obligations to operate in and to manage the Mauna Kea Science Reserve until 31 December 2033. The UH is currently in the process of seeking a renewal of the General Lease. Before MSE will enter a construction phase, the project must have both the project approved by DLNR, as well as the ability to operate beyond 2033 under a renewed General Lease for the Maunakea Science Reserve.
Project objectives
Science objectives
The science objectives for MSE were developed by a broadly based international science team, and are described in MSE's Detailed Science Case. The Detailed Science Case develops and justifies the science case for 12 observational surveys, each addressing a key science question, and groups those 12 cases into three science themes:
The Origin of Stars, Stellar Systems and the Stellar Populations of the Galaxy,
Linking Galaxies to the Large Scale Structure of the Universe, and
Illuminating the Dark Universe.
A set of six survey programs that are uniquely possible with MSE [ref] are used to define and constrain the technical characteristics of the observatory.
1. Exoplanets and stellar astrophysics
MSE will provide spectroscopic characterization at high spectral resolution and high signal to noise ratio of the faint end (g ~16) of the PLATO target distribution, to allow for statistical analysis of the properties of planet-hosting stars as a function of stellar and chemical parameters. This will allow for highly complete statistical studies of the prevalence of stellar multiplicity into the regime of hot Jupiters for this and other samples, and also directly measure binary fractions away from the Solar Neighbourhood.
2. Chemical tagging in the outer Milky Way
MSE will focus on understanding the outer components of the Galaxy: the halo, thick disk and outer disk - which are inaccessible to 4 metre class telescopes - largely through the use of its unique capability for chemical tagging experiments. Chemistry has the potential to be used in addition to, or instead of, phase space to reveal the stellar associations that represent the remnants of the building blocks of the Galaxy. MSE will push these techniques forward to help realize Freeman and Bland-Hawthorne's “New Galaxy"
3. Probing the dynamics of dark matter
MSE will probe the dynamics of dark matter over all astronomical spatial scales. For Milky Way dwarf galaxies, MSE will obtain complete samples of tens of thousands of member stars to very large radius and with multiple epochs to identify and remove binary stars. Such analyses will allow the internal dark matter profile to be derived with high accuracy and will probe the outskirts of the dark matter halos that account for external tidal perturbations as the dwarfs orbit the Galaxy. In the Galactic halo, high precision radial velocity mapping of every known stellar stream will reveal the extent of heating through interactions with dark sub-halos and place strong limits on the mass function of dark sub-halos around an L* galaxy. On cluster scales, MSE will use galaxies, planetary nebulae and globular clusters as dynamical tracers to provide a fully consistent portrait of dark matter halos across the mass function.
4. Examining the connection between galaxies and the large scale structure of the Universe
MSE will measure how galaxies evolve and grow relative to the dark matter structure in which they are embedded. This is done through mapping the distribution of stellar populations and supermassive black holes to the dark matter haloes and filamentary structures that dominate the mass density of the Universe, and doing so over all mass and spatial scales. MSE will provide a breakthrough in extragalactic astronomy by linking the formation and evolution of galaxies to the surrounding large-scale structure, across the full range of relevant spatial scales (from kiloparsecs to megaparsecs).
5. Following time-variable events
MSE will perform spectroscopic follow-up of time-variable events discovered by LSST, SKA and other all-sky transient surveys. With its large multiplex advantage and good sky overlap with other surveys, MSE can provide large-aperture followup of faint transient events using a few fibres while simultaneously continuing uninterrupted observation of main survey programs with the remainder of the installed fibre set.
6. The growth of supermassive black holes
MSE will undertake an extragalactic time domain program to measure directly the accretion rates and masses of a large sample of supermassive black holes through reverberation mapping. This information is essential for understanding accretion physics and tracing black hole growth over cosmic time. Reverberation mapping is the only distance-independent method of measuring black hole masses applicable at cosmological distances. MSE will greatly extend the few 10s of relatively low-luminosity AGN that currently have measurements of their black hole masses based on this technique.
Education and social responsibility
Complementing its science objectives MSE will enhance education, particularly STEM [Science, Technology, Engineering, and Mathematics] education, within the partner communities. While details of how MSE will be used to support education are being developed within those communities, CFHT has a proven track record with a number of innovative educational and community outreach programs, such as the Maunakea Scholars program, that engage the Hawai‘i community. Concepts proven through CFHT's existing projects have a broader applicability to the entire international partnership. Such programs will provide the basis for extending development projects into other STEM fields of study.
Observatory design
Telescope and enclosure
The MSE telescope will use an altitude-azimuth telescope mount supporting a segmented primary mirror with an effective aperture diameter of 10 meters. The mount concept is executed as a yoke-type structure and open space-frame telescope tube providing very good mechanical performance. The telescope is optically designed to be a prime focus telescope using a segmented primary mirror of 60 1.44m segments, delivering a circumscribed 11.25 meter aperture, and with a five element widefield corrector providing 1.5 square degrees of corrected field of view at the prime focus optical focal surface of the telescope. Compensation for atmospheric dispersion is an integral function of the widefield corrector optics. MSE's 11.25 meter aperture diameter necessitates replacing Canada-France-Hawai‘i Telescope's enclosure, designed for a 3.6 meter aperture telescope, with one that provides a suitable enclosure aperture while still being of a mass that the current building can support. A calotte style enclosure has been chosen as one that meets performance requirements, including good control of ventilation, while staying within the allowed mass and fiscal budgets.
The instrumentation package at the circular optical field of view is dominated by a hexagonal array of more than 4300 robotic fibre positioners, each of which samples the light at the focal surface with the tip of an optical fibre. Located in the outer chords between the hexagonal array of fibre positioners and the circular field of view are three imaging cameras used for telescope pointing acquisition, guidance, and focus measurement. A mechanical de-rotator stage keeps the instrumentation package stable in the sky coordinate system as the parallactic angle changes during observations.
Science instrumentation
Science data can be acquired in two possible spectral resolution modes: a high resolution of about R = 20,000 | 40,000, and a low/moderate resolution mode spanning R = 2,000 to R = 6,000. MSE is designed to be able to take spectra in both modes simultaneously during any observation. A fibre optic transmission system relays light gathered into the fibre tips at the telescope optical focal plane, to two banks of spectrometers that will measure the spectrum of the light gathered by each fibre. The fibre tips are positioned precisely at the position of astronomical interest in the focal plane by the array of remotely commandable tilting spine fibre positioners, each responsible for one fibre delivering light to one of the two spectrometer banks. The fibre transmission system uses high numeric aperture fibres to optically directly match the telescope focal ratio, and to provide good mechanical stability and optical throughput while minimizing focal-ratio degradation. The fibre core diameter, which sets the size of the sky sampled by each fibre tip, is different in those fibres used in the high resolution mode from those used in the low/moderate resolution mode, due to the difference in angular size of astronomical targets anticipated in each mode.
MSE's high resolution spectrometers are located within the concrete pier beneath the telescope. This bank of spectrometers measures spectra of light delivered by 1000 or more fibres, each dispersed in three spectral windows distributed over the visible light range of the instrument (360 nm to 900 nm). The low/moderate resolution spectrometers are located on the telescope, on outrigger platforms on the azimuth structure. This bank of spectrometers measures spectra of light delivered by 3200 or more fibres, each dispersed in four spectral windows. The windows provide continuous wavelength coverage over the visible and near-infrared bands from 360 nm to about 1.8 um when operated in their lowest resolution (a resolution of about 3,000), or about one-half the wavelength coverage when operated with moderate resolution (a resolution of about 6,000).
Science exposures are calibrated using both on-telescope and off-telescope lamps, and the twilight sky. During the observing night, on-telescope lamps illuminate the fibre inputs with lamps which give a broad continuum of energy over the wavelength range ("flats") and lamps which have a number of narrow-band emission lines ("arcs") such as hollow-cathode lamps. Lamp flat and arc calibration measurements are taken in the nighttime using the on-telescope calibration system, before and after every science observation, with the telescope mount and fibre positioner in the same observing configuration as used in the science observation. Lamp flat and arc calibration measurements are also taken in the daytime using the off-telescope calibration system, which can provide a measurement with higher signal to noise ratio. Lamp flats are also taken in a reference configuration of the telescope and positioner, to measure the relative energy of the twilight flats and the lamp flats. Twilight flat calibration measurements are used to give a more accurate representation of the energy distribution that the telescope sees during observation, than is possible with lamp calibration measurements alone.
Data
Scheduling MSE in an optimal way is a complex multi-faceted problem. Each "observing matrix" (one observation made at a single telescope pointing and suite of associated fibre positions) targets spectra from more than 4300 fibres pointing at objects selected from a few simultaneous surveys as well as calibration targets and targets of opportunity, and with spectrographs and indeed arms of spectrographs configured differently in each observing matrix. Objects are selected to be included in any observing matrix on the bases of science priority, time criticality, observing conditions, source brightness, sky brightness, calibration needs, and fibre yield (the fraction of fibre tips that can be placed on useful science objects). Software tools are being defined to automate steps in the operations sequence, going from survey definition to the delivery of science data. The final data product that MSE will deliver are 2-dimensional images of spectra, and 1-dimensional spectra, corrected for observatory signature, spectrally calibrated, and co-added where multiple measurements of the same object at the same resolution have been made. The data release policy will be finalized as the project approaches the start of construction, and is expected to include an immediate release of data to partner organization scientists and survey teams, and a later release to the public.
Maunakea summit facility
MSE is designed to achieve its science objectives with the least impact possible on the Maunakea summit both during construction and when operating the resultant observatory. The project is an upgrade to the existing CFHT facility, and predominantly is a replacement of the telescope, dome and instrumentation within the current building and re-using the current foundations without alterations. Some re-arrangement of equipment and space within the current building is necessary to meet the needs of MSE as well as those of building regulatory changes since the original construction, but the design objective is a building that looks substantially identical to the current CFHT summit building. The building internal structure will be improved to provide better performance during seismic events, and to accommodate the new enclosure and larger telescope. Other changes involve relocating equipment and labs to better exhaust heat away from the observing environment, and providing space for segmented mirror routine cleaning and coating operations.
While MSE will be operated remotely from the Waimea headquarters building for all nighttime operations, the summit building will continue to provide facilities for telescope and enclosure control during daytime engineering and maintenance work, as well as meeting workplace comfort and emergency staff safe haven needs.
References
External links
Official home page
MSE documents and publications
Telescopes | Maunakea Spectroscopic Explorer | [
"Astronomy"
] | 3,185 | [
"Telescopes",
"Astronomical instruments"
] |
57,638,150 | https://en.wikipedia.org/wiki/Algorithmic%20entities | Algorithmic entities refer to autonomous algorithms that operate without human control or interference. Recently, attention is being given to the idea of algorithmic entities being granted (partial or full) legal personhood. Professor Shawn Bayern and Professor Lynn M. LoPucki popularized through their papers the idea of having algorithmic entities that obtain legal personhood and the accompanying rights and obligations.
Legal algorithmic entities
Academics and politicians have been discussing over the last few years whether it is possible to have a legal algorithmic entity, meaning that an algorithm or AI is granted legal personhood. In most countries, the law only recognizes natural or real persons and legal persons. The main argument is that behind every legal person (or layers of legal persons), there is eventually a natural person.
In some countries there have been made some exceptions to this in the form of the granting of an environmental personhood to rivers, waterfalls, forests and mountains. In the past, some form of personhood also existed for certain religious constructions such as churches and temples.
Certain countries – albeit for publicity purposes – have shown willingness to grant (some form of) legal personhood to robots. On the 27th of October 2017, Saudi Arabia became to first country in the world to grant citizenship to a robot when it gave “Sophia” a passport. In the same year, official residency status was granted to a chatbot named “Shibuya Mirai” in Tokyo, Japan.
The general consensus is that AI in any case cannot be regarded as a natural or real person and that granting AI (legal) personhood at this stage is unwanted from a societal point of view. However, the academic and public discussions continue as AI software becomes more sophisticated and companies are increasingly implementing artificial intelligence to assist in all aspects of business and society. This leads to some scholars to wonder whether AI should be granted legal personhood as it is not unthinkable to one day have a sophisticated algorithm capable of managing a firm completely independent of human interventions.
Brown argues that the question of whether legal personhood for AI may be granted is tied directly to the issue of whether AI can or should even be allowed to legally own property. Brown “concludes that that legal personhood is the best approach for AI to own personal property.” This is an especially important inquiry since many scholars already recognize AI as having possession and control of some digital assets or even data. AI can also create written text, photo, art, and even algorithms, though ownership of these works is not currently granted to AI in any country because it is not recognized as a legal person.
United States
Bayern (2016) argues that this is already possible currently under US law. He states, that, in the United States, creating an AI controlled firm without human interference or ownership is already possible under current legislation by creating a “zero member LLC”:
Sherer (2018) argues – after conducting an analysis on New York's (and other states’) LLC law(s), the Revised Uniform Limited Liability Company Act (RULLCA) and US case law on fundamentals of legal personhood – that this option is not viable, but agrees with Bayern on the existence of a ‘loophole’ whereby an AI system could “effectively control a LLC and thereby have the functional equivalent of legal personhood”. Bayern's loophole of “entity cross-ownership” would work as follows:
Unlike the zero member LLC, the entity cross-ownership would not trigger a response by the law for having a memberless entity as what remains are two entities each having one member. In corporations, this sort of situations is often prevented by formal provisions in the statutes (predominantly for voting rights for shares), however, such limitations do not seem to be in place for LLCs as they are more flexible in arranging control and organization.
Europe
In Europe, certain academics from different countries have started to look at the possibilities in their respective jurisdictions. Bayern et al. (2017) compared the UK, Germany and Switzerland to the findings of Bayern (2016) earlier for the US to see whether such “loopholes” in the law exist there as well to set up an algorithmic entity.
Some smaller jurisdiction are going further and adapting their laws for the 21st century technological changes. Guernsey has granted (limited) rights to electronic agents and Malta is currently busy creating a robot citizenship test.
While it is unlikely the EU would allow for AI to receive legal personality at this moment, the European Parliament did however request the European Commission in a February 2017 resolution to “creating a specific legal status for robots in the long run, so that at least the most sophisticated autonomous robots could be established as having the status of electronic persons responsible for making good any damage they may cause, and possibly applying electronic personality to cases where robots make autonomous decisions or otherwise interact with third parties independently”.
Not all parts of the supranational European bodies agreed as the European Economic and Social Committee gave in its own initiative an opposing opinion given May 2017: “The EESC is opposed to any form of legal status for robots or AI (systems), as this entails an unacceptable risk of moral hazard. Liability law is based on a preventive, behavior-correcting function, which may disappear as soon as the maker no longer bears the liability risk since this is transferred to the robot (or the AI system). There is also a risk of inappropriate use and abuse of this kind of legal status.”
In reaction to the European Parliament's request, the European Commission set up a High Level Expert Group to tackle issues and take initiative in a number of subjects relating to automation, robotics and AI. The High Level Expert Group released a draft document for AI ethical guidelines and a document defining AI in December 2018. The document on ethical guidelines was opened for consultation and received extensive feedback. The European Commission is taking a careful approach legislating AI by emphasizing on ethics, but at the same time – as the EU is behind in AI research to the United States and China – focusing on how to narrow the gap with competitors by creating a more inviting regulatory framework for AI research and development. Giving (limited) legal personality to AI or even allow certain forms of algorithmic entities might create an extra edge.
References
Existential risk from artificial general intelligence
Regulation of robots
Regulation of artificial intelligence | Algorithmic entities | [
"Technology"
] | 1,268 | [
"Computing and society",
"Existential risk from artificial general intelligence",
"Regulation of artificial intelligence"
] |
57,638,273 | https://en.wikipedia.org/wiki/Gloeoporus%20africanus | Gloeoporus africanus is a species of crust fungus in the family Irpicaceae. Found in Africa, it was described as a new species in 2018 by Paul Jung and Young Wood Lim. The type collection was made in Bwindi Impenetrable National Park, Uganda, where it was found growing on a fallen branch. It is somewhat similar in appearance to Bjerkandera adusta, but is distinguished from that fungus by its angular pores and the white edges of the actively growing pore surface. G. africanus has a monomitic hyphal system, and its generative hyphae have clamp connections. Its spores are sausage-shaped (allantoid), measuring 3.8–4.2 by 0.6–0.7 μm.
References
Fungi described in 2018
Fungi of Africa
Irpicaceae
Fungus species | Gloeoporus africanus | [
"Biology"
] | 179 | [
"Fungi",
"Fungus species"
] |
57,638,316 | https://en.wikipedia.org/wiki/Gloeoporus%20orientalis | Gloeoporus orientalis is a species of crust fungus in the family Irpicaceae. Found in East Asia, it was described as a new species in 2018 by Paul Jung and Young Wood Lim. The type collection was made in Geojedo, Korea, where it was found growing on a fallen angiosperm trunk.
Gloeoporus orientalis has a monomitic hyphal system, and its generative hyphae have clamp connections. Its spores are sausage-shaped (allantoid), measuring 3.0–3.6 by 0.6–0.8 μm, while the basidia are club shaped and measure 11.4–12.5 by 2.5–2.8 μm. G. dichrous is similar in appearance to G. orientalis, but can the former can be distinguished by its larger pores, larger basidia, and the more cylindrical shape of its spores. G. orientalis has been found in China, Taiwan, Korea, and Japan.
References
Fungi described in 2018
Fungi of Asia
Irpicaceae
Fungus species | Gloeoporus orientalis | [
"Biology"
] | 226 | [
"Fungi",
"Fungus species"
] |
57,638,831 | https://en.wikipedia.org/wiki/NGC%203315 | NGC 3315 is a lenticular galaxy located about 185 million light-years away in the constellation Hydra. It was discovered by astronomer Edward Austin on March 24, 1870. It is a member of the Hydra Cluster.
See also
List of NGC objects (3001–4000)
NGC 3305
References
External links
Hydra Cluster
Hydra (constellation)
Lenticular galaxies
3315
31540
Astronomical objects discovered in 1870
Discoveries by Edward Austin | NGC 3315 | [
"Astronomy"
] | 85 | [
"Hydra (constellation)",
"Constellations"
] |
57,638,895 | https://en.wikipedia.org/wiki/Unseen%20species%20problem | The unseen species problem in ecology deals with the estimation of the number of species represented in an ecosystem that were not observed by samples. It more specifically relates to how many new species would be discovered if more samples were taken in an ecosystem. The study of the unseen species problem was started in the early 1940s, by Alexander Steven Corbet. He spent two years in British Malaya trapping butterflies and was curious how many new species he would discover if he spent another two years trapping. Many different estimation methods have been developed to determine how many new species would be discovered given more samples.
The unseen species problem also applies more broadly, as the estimators can be used to estimate any new elements of a set not previously found in samples. An example of this is determining how many words William Shakespeare knew based on all of his written works.
The unseen species problem can be broken down mathematically as follows: If independent samples are taken, , and then if more independent samples were taken, the number of unseen species that will be discovered by the additional samples is given by
with being the second set of samples.
History
In the early 1940s Alexander Steven Corbet spent 2 years in British Malaya trapping butterflies. He kept track of how many species he observed, and how many members of each species were captured. For example, there were 74 different species of which he captured only 2 individual butterflies.
When Corbet returned to the United Kingdom, he approached biostatistician Ronald Fisher and asked how many new species of butterflies he could expect to catch if he went trapping for another two years; in essence, Corbet was asking how many species he observed zero times.
Fisher responded with a simple estimation: for an additional 2 years of trapping, Corbet could expect to capture 75 new species. He did this using a simple summation (data provided by Orlitsky in the table from the Example below:
Here corresponds to the number of individual species that were observed times. Fisher's sum was later confirmed by Good–Toulmin.
Estimators
To estimate the number of unseen species, let be the number of future samples () divided by the number of past samples (), or . Let be the number of individual species observed times (for example, if there were 74 species of butterflies with 2 observed members throughout the samples, then ).
Good–Toulmin estimator
The Good–Toulmin (GT) estimator was developed by Good and Toulmin in 1953. The estimate of the unseen species based on the Good–Toulmin estimator is given by
The Good–Toulmin Estimator has been shown to be a good estimate for values of The Good–Toulmin estimator also approximately satisfies
This means that estimates to within as long as
However, for , the Good–Toulmin estimator fails to capture accurate results. This is because, if increases by for with meaning that if grows super-linearly in but can grow at most linearly with Therefore, when grows faster than and does not approximate the true value.
To compensate for this, Efron and Thisted in 1976 showed that a truncated Euler transform can also be a usable estimate (the "ET" estimate):
with
where and
where is the location chosen to truncate the Euler transform.
Smoothed Good–Toulmin estimator
Similar to the approach by Efron and Thisted, Alon Orlitsky, Ananda Theertha Suresh, and Yihong Wu developed the smooth Good–Toulmin estimator. They realized that the Good–Toulmin estimator failed because of the exponential growth, and not its bias. Therefore, they estimated the number of unseen species by truncating the series
Orlitsky, Suresh, and Wu also noted that for distributions with , the driving term in the summation estimate is the term, regardless of which value of is chosen. To solve this, they selected a random nonnegative integer , truncated the series at , and then took the average over a distribution about . The resulting estimator is
This method was chosen because the bias of shifts signs due to the coefficient. Averaging over a distribution of therefore reduces the bias. This means that the estimator can be written as the linear combination of the prevalence:
Depending on the distribution of chosen, the results will vary. With this method, estimates can be made for , and this is the best possible.
Species discovery curve
The species discovery curve can also be used. This curve relates the number of species found in an area as a function of the time. These curves can also be created by using estimators (such as the Good–Toulmin estimator) and plotting the number of unseen species at each value for .
A species discovery curve is always increasing, as there is never a sample that could decrease the number of discovered species. Furthermore, the species discovery curve is also decelerating the more samples taken, the fewer unseen species are expected to be discovered. The species discovery curve will also never asymptote, as it is assumed that although the discovery rate might become infinitely slow, it will never actually stop. Two common models for a species discovery curve are the logarithmic and the exponential function.
Example: Corbet's butterflies
As an example, consider the data Corbet provided Fisher in the 1940s. Using the Good–Toulmin model, the number of unseen species is found using
This can then be used to create a relationship between and .
{| class="wikitable"
|+ Data provided to Fisher by Corbet
!Number of observed members,
!1
!2
!3
!4
!5
!6
!7
!8
!9
!10
!11
!12
!13
!14
!15
|-
|Number of species,
|118
|74
|44
|24
|29
|22
|20
|19
|20
|15
|12
|14
|6
|12
|6
|}
This relationship is shown in the plot below.
From the plot, it is seen that at , which was the value of that Corbet brought to Fisher, the resulting estimate of is 75, matching what Fisher found. This plot also acts as a species discovery curve for this ecosystem and defines how many new species will be discovered as increases (and more samples are taken).
Other uses
There are numerous uses for the predictive algorithm. Knowing that the estimators are accurate, it allows scientists to extrapolate accurately the results of polling people by a factor of 2. They can predict the number of unique answers based on the number of people that have answered similarly. The method can also be used to determine the extent of someone's knowledge.
Example: How many words did Shakespeare know?
Based on research of Shakespeare's known works done by Thisted and Efron, there are 884,647 total words. The research also found that there are at total of different words that appear more than 100 times. Therefore, the total number of unique words was found to be 31,534. Applying the Good–Toulmin model, if an equal number of works by Shakespeare were discovered, then it is estimated that unique words would be found. The goal would be to derive for . Thisted and Efron estimate that , meaning that Shakespeare most likely knew over twice as many words as he actually used in all of his writings.
See also
Species discovery curve
Alexander Steven Corbet
Ronald Fisher
German tank problem
References
Ecology
Biostatistics | Unseen species problem | [
"Biology"
] | 1,535 | [
"Ecology"
] |
57,639,032 | https://en.wikipedia.org/wiki/Dihydromaltophilin | Dihydromaltophilin, or heat stable anti-fungal factor (HSAF), is a secondary metabolite of bacteria in the genera Streptomyces and Lysobacter. HSAF is a polycyclic tetramate lactam containing a single tetramic acid unit and a 5,5,6-tricyclic system. HSAF has been shown to have anti-fungal activity mediated through the disruption of a ceramide synthase that is unique to fungi.
Biosynthesis
The backbone of HSAF is formed through a hybrid PKS-NRPS cluster containing one nonribosomal peptide synthase (NRPS) module and one polyketide synthase (PKS) module. The single PKS module functions in a non-canonical fashion in that it is an iterative type I PKS responsible for the generation of the two unique polyketides needed in the backbone of HSAF using malonyl-CoA as both the starter and extender unit, while the NRPS module is responsible for the linking of the polyketides to an L-ornithine unit and the initial cyclization to create the tetramate back bone. The coding region related to HSAF production contains a PKS-NRPS with a total of 9 domains, (KS-AT-DH-KR-ACP-C-A-PCP-TE), while a cascade of FAD-dependent redox reactions (OX1-OX4) flank the PKS-NRPS cluster proposed to be responsible for formation of the 5,5,6-tricyclic system, there are additional coding regions for a putative regulator, an arginase for L-ornithine production from Arginine, and a transporter which flank the PKS-NRPS.
References
Polyketides | Dihydromaltophilin | [
"Chemistry"
] | 391 | [
"Biomolecules by chemical classification",
"Natural products",
"Polyketides"
] |
57,639,170 | https://en.wikipedia.org/wiki/Cembratrienol | Cembratrienol (CBTol) is a tertiary alcohol produced in the leaves of tobacco plants. It acts as an insect repellent.
History
In 2018 researchers isolated the sections of the tobacco genome that produce CBTol molecules. They incorporated those genes into Escherichia coli bacteria. When fed wheat bran, those bacteria produced CBTol. The chemical was extracted via centrifugal separation chromatography and incorporated into a biodegradable, non-toxic and environmentally-friendly repellent that can be sprayed directly onto crops. In laboratory tests, aphids avoided treated crops. One side benefit was that it kills multiple types of gram-positive bacteria that are harmful to humans.
See also
Crop protection
Insecticide
Pesticide
References
External links
Insect repellents
Tobacco
Cyclic compounds
Tertiary alcohols
Unsaturated compounds
Diterpenes
Isopropyl compounds | Cembratrienol | [
"Chemistry"
] | 182 | [
"Organic compounds",
"Unsaturated compounds"
] |
70,052,455 | https://en.wikipedia.org/wiki/David%20Fowler%20%28physicist%29 | David Fowler (born 1 June 1950) is a British environmental physicist, recognized as an authority on atmospheric pollution. He specializes in micrometeorology, the land-atmosphere exchange of trace gases and particles, and the effects of pollutants on vegetation.
Education and career
Fowler gained a B.Sc. in environmental physics at the University of Nottingham in 1972, followed by a Ph.D. at the same university in 1976, before moving to the Institute of Terrestrial Ecology in Edinburgh (later incorporated into the Centre for Ecology & Hydrology), where he spent the next four decades of his career. He has authored around 250 peer-reviewed papers.
Policy work
Apart from scientific research, Fowler has also worked on the application of air quality science to public policy in both the UK and Europe. He has been a member of around two dozen scientific committees, including the Royal Society Global Environmental Research Committee (of which he has been chair since 2011), and the Air Quality Expert Group, of which he is an ad-hoc member.
In 2008, Fowler chaired a committee of European air pollution experts to produce a major study of ground-level ozone for the Royal Society, which concluded "that existing emission controls will not be sufficient to reduce ozone concentrations to levels acceptable for human health and environmental protection" and called "for renewed global action to address ozone and its precursors".
Awards
Fowler became an honorary professor of the University of Nottingham in 1991, was elected a Fellow of the Royal Society of Edinburgh in 1999, and a Fellow of the Royal Society of London in 2002. He was awarded the CBE in 2005 for services to atmospheric sciences.
Selected publications
References
External links
Living people
1950 births
English physicists
Commanders of the Order of the British Empire
Fellows of the Royal Society
Fellows of the Royal Society of Edinburgh
Alumni of the University of Nottingham
British civil servants
Academics of the University of Nottingham
Environmental scientists
Air pollution in the United Kingdom | David Fowler (physicist) | [
"Environmental_science"
] | 384 | [
"Environmental scientists",
"British environmental scientists"
] |
70,052,788 | https://en.wikipedia.org/wiki/Neurospora%20sitophila | Neurospora sitophila is a species of fungus also known as red bread fungus or orange bread fungus. It is a mold that spoils various foods and is responsible for occupational asthma in the wood and cork industry.
Classification
Chrysonilia sitophila is the anamorphic counterpart of Neurospora sitophila (teleomorph). Its position in the classification is:
Sordariaceae, Sordariales, Sordariomycetidae, Sordariomycetes, Ascomycota, Fungi.
History
At the time of its discovery, in 1843, this fungus was named "Penicillium sitophilum" by Montagne and "Oïdium aurantiacum" by Léveillé, but it is now considered not to belong to either genus Oidium nor Penicillium.
In 1848, Anselme Payen reported that it resisted temperatures above 100 degrees, a fact which played a role in discussions of spontaneous generation.
In 2010, Chrysonilia sitophila, the asexual state of neurospora sitophilia, was found to be linked to a case of occupational asthma in a worker exposed to ground coffee.
References
Bibliography
Montagne, C. "Quatrième centurie de plantes cellulaires exotiques nouvelles." Annales des Sciences Naturelles, Botanique, 2e sér., vol. 20, 1843, pp. 352–379.
Payen, A. (rapporteur) "Extrait d'un rapport adressé à M. Le Maréchal Duc de Dalmatie, Ministre de la Guerre, Président du Conseil, sur une altération extraordinaire du pain de munition", Annales de Chimie et de Physique, 3e sér., t. 9, 1843, pp. 5–21.
Payen, A. "Températures que peuvent supporter les sporules de l'Oïdium aurantiacum sans perdre leur faculté végétative", Comptes rendus de l'Académie des Sciences, 27, 1848, pp. 4–5.
Payen, A., in Milne Edwards, "Remarques sur la valeur des faits qui sont considérés par quelques naturalistes comme étant propres à prouver l'existence de la génération spontanée des animaux", Payen's intervention, Comptes rendus de l'Académie des Sciences, session of January 3, 1859, vol. 48, 1859, pp. 23–36, online.
Pasteur, L. 1862. " L'influence de la température sur la fécondité des spores de Mucédinées. ", Comptes rendus de l'Académie des sciences, t. 52, 1861, p. 16-19.
Gauthier de Claubry, « Sur quelques points de l'histoire de l'oïdium aurantiacum », dans Comptes rendus de l'Académie des Sciences, t. 73 (1871), pp. 725–726, online.
D.D. Perkins, " The first published scientific study of Neurospora, including a description of photoinduction of carotenoids ", Fungal Genetics Stock Center
Tarlo S. M. ; Wai Y. ; Dolovich J. ; Summerbell R., " Occupational asthma induced by Chrysonilia sitophila in the logging industry ", Journal of allergy and clinical immunology, 1996, vol. 97, n° 6, pp. 1409–1413.
Sordariomycetes
Fungus species | Neurospora sitophila | [
"Biology"
] | 781 | [
"Fungi",
"Fungus species"
] |
70,053,019 | https://en.wikipedia.org/wiki/Molvizarin | Molvizarin is a cytotoxic acetogenin derivate with the molecular formula C35H62O7 which has been isolated from the bark of the plant Annona cherimolia. Molvizarin has in vitro activity against tumor cells.
References
Polyketides
Lactones | Molvizarin | [
"Chemistry"
] | 67 | [
"Biomolecules by chemical classification",
"Natural products",
"Organic compounds",
"Polyketides",
"Organic compound stubs",
"Organic chemistry stubs"
] |
70,053,407 | https://en.wikipedia.org/wiki/III%20Zw%202 | III Zw 2 is a Seyfert 1 galaxy located in the Pisces constellation. It has a redshift of 0.089 and is notable as the first of its kind to exhibit a superluminal jet.
Discovery
III Zw 2 was first discovered by Fritz Zwicky via a 48-inch Schmidt survey as a stellar object with faint wisps. However, it was confirmed to have a Seyfert morphology with classical broadline characteristic based on further spectroscopic studies. It was also included in Palomar Green quasar sample.
Characteristics
The host galaxy of III Zw 2 was initially classified as a spiral galaxy. However according to a recent study made on its budge and disk decomposition via Hubble Space Telescope in 2009, it has since been reclassified as an elliptical galaxy. It has a star-forming tidal bridge feature indicating a merger with a companion galaxy. Furthermore, III Zw 2 belongs to a class of radio-intermediate quasars and is a member of a triple galaxy system.
Active nucleus
The nucleus of III Zw 2 is active. In additional, to its superluminal jet, the galaxy shows two distinctive γ-ray flares happening between November 2009 and May 2010, according to observations by Fermi-LAT. It is also known to have a highly variable radio core flux density between factor of 20-30.
Black hole
III Zw 2 contains a supermassive black hole of 7.4 × 108 M⊙. The black hole is responsible for producing an ionized wind outflow with a velocity of (−1780 ± 670) km s−1. Approximately every five years the galaxy emits dramatic radio outbursts.
References
Quasars
Pisces (constellation)
Seyfert galaxies
000737
1501
Active galaxies | III Zw 2 | [
"Astronomy"
] | 366 | [
"Pisces (constellation)",
"Constellations"
] |
70,053,471 | https://en.wikipedia.org/wiki/Merle%20Gold | Merle Eleanor Gold (née Tuberg) (7 March 1921- 29 September 2017) was an American astrophysicist, best known for her study of the Sun with Nobel Laureate Subrahmanyan Chandrasekhar.
Early life and education
Merle Gold was born on 7 March 1921 and grew up in Rochester, Minnesota to Nathaniel and Eleanor Tuberg. She graduated high school in 1939 as Valedictorian of her class. She trained as a medical secretary at Mayo Clinic for two years before undertaking her undergraduate degree at University of Chicago. After graduating, she went on to complete her PhD in astrophysics under Subrahmanyan Chandrasekhar at Yerkes Observatory. Her thesis was on how absorption lines detected from the Sun vary across the solar disk.
Research and career
In 1946, Merle was awarded a post-doctoral fellowship at University of Cambridge. She published one research paper after her thesis on the lifetimes of clusters of nebulae outside the Milky Way. In 1971, she became an editor at Cornell School of Agriculture where she worked until her retirement.
Personal life
She married astronomer Thomas Gold in 1947 and they had 3 children together before divorcing in 1971. Merle died in Ithaca, New York on 29 September 2017.
Notable publications
Merle Tuberg. (November 1943). "On the Lifetime of Clusters of Extragalactic Nebulae". Astrophysical Journal. 98. 501–503. doi: 10.1086/144582
Merle Tuberg. (March 1946). "The Variations of Absorption-Line Contours across the Solar Disc". Astrophysical Journal. 103. 145. doi:10.1086/144799
References
1921 births
2017 deaths
American women astrophysicists
Women astronomers
University of Chicago alumni
20th-century American astronomers | Merle Gold | [
"Astronomy"
] | 362 | [
"Women astronomers",
"Astronomers"
] |
70,053,543 | https://en.wikipedia.org/wiki/Misha%20%28Mandaeism%29 | In Mandaeism, misha () is anointing sesame oil used during rituals such as the masbuta (baptism) and masiqta (death mass), both of which are performed by Mandaean priests.
Etymology
The Mandaic word miša shares the same root with Mšiha ("Messiah"; ). However, Mandaeans do not use the word mšiha to refer to Mandaeans who have been anointed during rituals, in order to distance themselves from Christianity.
In the Qulasta
Several prayers in the Qulasta are recited over the oil, including prayers 48, 63, and 73. In some prayers, misha referred to as misha dakia, or "pure oil."
See also
Holy anointing oil
Oil of catechumens
Riha (incense)
References
Mandaic words and phrases
Oils
Mandaean religious objects | Misha (Mandaeism) | [
"Chemistry"
] | 186 | [
"Oils",
"Carbohydrates"
] |
70,055,352 | https://en.wikipedia.org/wiki/IRAS%2018357%E2%80%930604 | IRAS 18357–0604 is a yellow hypergiant (YHG) star located in the constellation of Scutum, estimated to be about 19,600 light years, or 6,000 parsecs, away. IRAS 18357–0604 is remarkably similar to IRC +10420, another yellow hypergiant in the constellation of Aquila.
Position
A distance of 6,000 parsecs (inferred from the systemic velocity of the star) would place IRAS 18357–0604 within the red supergiant (RSG) "association" in the Scutum-Centaurus arm, which contains clusters such as RSGC1 and RSGC2. The luminosity derived from the distance is consistent with IRAS 18357–0604 being formed from the same star formation burst as that which created the red supergiants in the area. The star is also located about 14 arcminutes from RSGC2, so the possibility of it being a runaway from the cluster cannot be excluded, but replicating its properties in such a scenario would require an unexpectedly extreme mass-loss rate during its preceding red supergiant phase.
Properties
IRAS 18357–0604 is likely to be a very luminous star, like all YHGs. Assuming a distance of 6,000 parsecs, the star would have a bolometric luminosity of about . Based on its spectrum, the star likely has a temperature of about . Applying the Stefan-Boltzmann law to these parameters means that the star has a radius of about .
Evolutionary Status
In the RSG agglomerate of which IRAS 18357–0604 may be a part, RSGC1 and RSGC2 represent the youngest and oldest clusters in the area. This suggests that star formation in the area peaked over the last 10-20 million years, which means that evolved stars in the area have initial masses between and . If this age and mass range is applicable to the wider RSG association, the parameters of IRAS 18357–0604 are consistent with membership of the association. Theoretical models of rotating stars are able to reproduce IRAS 18357–0604's parameters assuming an initial mass of and an age comparable to that of RSGC1 (~12 Myr). If IRAS 18357's initial mass is closer to , it may be the progenitor of a core-collapse type IIb supernova, and it might explode in the relatively near future. Instead, if its initial mass is closer to , it may evolve through an LBV stage and get slightly hotter before exploding in a type IIb supernova.
Notes
References
Scutum (constellation)
A-type hypergiants
IRAS catalogue objects | IRAS 18357–0604 | [
"Astronomy"
] | 573 | [
"Scutum (constellation)",
"Constellations"
] |
70,057,643 | https://en.wikipedia.org/wiki/YJK | YJK is a proprietary color space implemented by the Yamaha V9958 graphic chip on MSX2+ computers. It has the advantage of encoding images by implementing less resolution for color information than for brightness, taking advantage of the human visual systems' lower acuity for color differences. This saves memory, transmission and computing power.YJK is composed of three components: , and . is similar to luminance (but computed differently), and are the chrominance components (representing the red and green color differences). The component is a 5-bit value (0 to 31), specified for each individual pixel. The and components are stored together in 6 bits (-32 to 31) and shared between 4 nearby pixels (4:2:0 chroma sub-sampling).
This arrangement allows for the encoding of 19,268 different colors.
While conceptually similar to YUV, chroma sampling, numerical relationship between the components, and transformation to and from RGB are different in YJK.
Formulas
The three component signals are created from an original RGB (red, green and blue) source. The weighted values of , and are added together to produce a single signal, representing the overall brightness of that pixel. The signal is then created by subtracting the from the red signal of the original RGB, and then scaling; and by subtracting the from the green, and then scaling by a different factor.
These formulae approximate the conversion between the RGB color space and YJK:
From RGB to YJK:
From YJK to RGB:
The component of YJK is not true luminance, since the green component has less weight than the blue component. Also, contrary to YUV where chrominance is based on Red-Blue differences, on YJK its calculated based on Red-Green differences.
References
See also
YUV
MSX2+
Color space
MSX hardware
MSX2+ microcomputer | YJK | [
"Mathematics"
] | 402 | [
"Color space",
"Space (mathematics)",
"Metric spaces"
] |
70,057,902 | https://en.wikipedia.org/wiki/HD%2022676 | HD 22676 (HR 1109) is a solitary star in the southern circumpolar constellation Mensa. It has an apparent magnitude of 5.67, making it faintly visible to the naked eye and is currently located at a distance of . However, it is recceding from the sun with a radial velocity of .
HD 22676 has a stellar classification of G8 III, which indicates that is an evolved late G-type giant star currently on the horizontal branch, specifically the red clump region. At an age of 700 million years, it has expanded to 9.33 times the radius of the Sun. It has 2.36 times the Sun's mass and radiates at approximately 58 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,109 K, which gives it a yellow glow. HD 22676 is slightly metal enriched with an iron abundance 115% that of the Sun and spins lesuirely with a projected rotational velocity of .
References
Mensa (constellation)
G-type giants
022676
016290
1109
Mensa, 1
Horizontal-branch stars
Durchmusterung objects | HD 22676 | [
"Astronomy"
] | 243 | [
"Mensa (constellation)",
"Constellations"
] |
70,058,377 | https://en.wikipedia.org/wiki/Bebtelovimab | Bebtelovimab is a monoclonal antibody developed by AbCellera and Eli Lilly as a treatment for COVID-19.
Possible side effects include itching, rash, infusion-related reactions, nausea and vomiting.
Bebtelovimab works by binding to the spike protein of the virus that causes COVID-19, similar to other monoclonal antibodies that have been authorized for the treatment of high-risk people with mild to moderate COVID-19 and shown a benefit in reducing the risk of hospitalization or death. Bebtelovimab is a neutralizing human immunoglobulin G1 (IgG1) monoclonal antibody, isolated from a patient who has recovered from the Coronavirus disease 2019 (COVID-19), directed against the spike (S) protein of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), that can potentially be used for immunization against COVID-19.
, bebtelovimab is not authorized for emergency use in the US because it is not expected to neutralize Omicron subvariants BQ.1 and BQ.1.1.
Medical uses
Bebtelovimab was granted an emergency use authorization (EUA) by the US Food and Drug Administration (FDA) in February 2022, and revoked it in November 2022. The EUA for bebtelovimab is for the treatment of mild to moderate COVID-19 in people aged 12 years of age and older weighing at least with a positive COVID-19 test, and who are at high risk for progression to severe COVID-19, including hospitalization or death, and for whom alternative COVID-19 treatment options approved or authorized by the FDA are not accessible or clinically appropriate.
Bebtelovimab is not authorized for people who are hospitalized due to COVID-19 or require oxygen therapy due to COVID-19. Treatment with bebtelovimab has not been studied in people hospitalized due to COVID-19.
Bebtelovimab is not expected to neutralize Omicron subvariants BQ.1 and BQ.1.1.
History
Bebtelovimab emerged from a collaboration between Eli Lilly and AbCellera. Bebtelovimab was discovered by AbCellera and the National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center.
Society and culture
Legal status
Bebtelovimab was authorized for medical use in the United States via an emergency use authorization in February 2022.
, bebtelovimab is not authorized for emergency use in the US because it is not expected to neutralize Omicron subvariants BQ.1 and BQ.1.1. Eli Lilly and its authorized distributors have paused commercial distribution of bebtelovimab until further notice by the U.S. Food and Drug Administration (FDA).
Names
Bebtelovimab is the proposed international nonproprietary name (pINN).
References
External links
Antiviral drugs
Experimental monoclonal antibodies
COVID-19 drug development | Bebtelovimab | [
"Chemistry",
"Biology"
] | 657 | [
"Antiviral drugs",
"COVID-19 drug development",
"Biocides",
"Drug discovery"
] |
70,059,154 | https://en.wikipedia.org/wiki/Pixel%207 | The Pixel 7 and Pixel 7 Pro are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line. They serve as the successor to the Pixel 6 and Pixel 6 Pro, respectively. The phones were first previewed in May 2022, during the Google I/O keynote. They are powered by the second-generation Google Tensor chip, and feature a design similar to that of the Pixel 6 series. They shipped with Android 13.
The Pixel 7 and Pixel 7 Pro were officially announced on October 6, 2022, at the annual Made by Google event, and were released in the United States on October 13. They were succeeded by the Pixel 8 and Pixel 8 Pro in 2023.
History
The Pixel 7 and Pixel 7 Pro were previewed by Google on May 11, 2022, during the 2022 Google I/O keynote. During the keynote, the company confirmed that the phones would feature the second-generation Google Tensor system-on-chip (SoC), which had been in development by October 2021. The phones were approved by the Federal Communications Commission (FCC) in August 2022. Google officially announced the phones on October 6, 2022, alongside the Pixel Watch smartwatch, at the annual Made by Google event, and became available in 17 countries on October 13. A portion of the phones were manufactured by Foxconn in Vietnam, shifting production from southern China. Google requested approximately eight million Pixel 7 units from suppliers, with the goal of increasing its sales numbers twofold. During the launch event, Google also announced the phones' official cases, which became available for pre-order on the same day with three color options for each phone. Pre-orders for the phones began on the same day as the announcement.
Specifications
Design
The Pixel 7 and Pixel 7 Pro both feature the two-tone back color scheme and large camera bar introduced in the Pixel 6 and Pixel 6 Pro, with the camera bar now made of aluminum. The front of the phones also retain the Pixel 6 series' centered hole-punch display notch. They are each available in three colors:
Hardware
The Pixel 7 has a FHD+ 1080p OLED display at 416 ppi with a pixel resolution and a 20:9 aspect ratio, while the Pixel 7 Pro has a QHD+ 1440p LTPO OLED curved-edge display at 512 ppi with a pixel resolution and a 19.5:9 aspect ratio. The Pixel 7 has a 90 Hz refresh rate while the Pixel 7 Pro has a 120 Hz variable refresh rate. Both phones contain a 50 megapixel wide rear camera and a 12 megapixel ultrawide rear camera, with the Pixel 7 Pro featuring an additional 48 megapixel telephoto 5× optical zoom rear camera. The front camera on both phones contains a 10.8 megapixel ultrawide lens. The phones bring back the Pixel 4 and Pixel 4 XL's Face Unlock facial recognition system, except the feature is now solely powered by the front camera rather than Project Soli radar technology.
The Pixel 7 has a 4355 mAh battery, while the Pixel 7 Pro has a 5000 mAh battery. Both phones support fast charging, Qi wireless charging, as well as reverse wireless charging. The Pixel 7 is available in 128 or 256 GB of storage and 8 GB of RAM, and the Pixel 7 Pro is available in 128, 256, or 512 GB of storage and 12 GB of RAM. In addition to the second-generation Tensor chip, both phones are also equipped with the Titan M2 security module, along with an under-display optical fingerprint scanner, stereo speakers, and Gorilla Glass Victus. Counterpoint Research calculated that the Pixel 7 Pro cost an estimated to manufacture.
Software
The Pixel 7 and Pixel 7 Pro shipped with Android 13 and version 8.7 of the Google Camera app at launch. It was originally set to receive three years of major OS upgrades and five years of security updates, but the former was later increased to five years, with support extending to 2027. In addition to enhancements to Night Sight and Real Tone, camera features introduced on the Pixel 7 and Pixel 7 Pro include Guided Frame, Photo Unblur, and Cinematic Blur. A macro photography mode is also available on the Pixel 7 Pro to accompany its additional telephoto lens, as are upgrades to Super Res Zoom. The Direct My Call feature and Recorder app both received performance upgrades, while Google announced that its VPN service from Google One would be bundled with the Pixel 7 series at no additional charge. The Pixel 7 and Pixel 7 Pro only run apps that have 64-bit binaries, the first Android smartphones with such a restriction. As part of a partnership with Google, Snapchat and TikTok announced support for 10-bit HDR video on the Pixel 7 series.
Marketing
Similar to the previous year, Pixel 7-themed potato chips were made available in Japan weeks prior to the phones' launch event. In October 2022, Google partnered with the NBA to produce a series of advertisements for the Pixel lineup featuring multiple NBA athletes. In February 2023, Google released a commercial titled "Fixed on Pixel" which advertised the Pixel 7's Magic Eraser feature, ahead of its airing during Super Bowl LVII. Featuring Amy Schumer, Doja Cat, and Giannis Antetokounmpo, the 90-second commercial marked Google's second Super Bowl spot in a row to market the Pixel. The song "We Run This" by Missy Elliot is used in the commercial. "Fixed on Pixel" was positively received by viewers, with Northwestern University's Kellogg School of Management placing it among the highest-ranked spots of Super Bowl LVII. People and Teen Vogue both named it as one of the best commercials of the event, while CBS Sports ranked it as second-best and Tom's Guide labeled it as the best. It was the fifth most-watched Super Bowl LVII commercial on YouTube, and was ranked 12th on USA Today Super Bowl Ad Meter, scoring 5.81 points on a scale of 10. In June 2023, the Pixel 7 Pro and Pixel Fold were featured in a series of comparative advertisements targeting the iPhone.
Reception
Critical response
Following the Pixel 7 and Pixel 7 Pro's reveal at the 2022 Google I/O, Sean Hollister of The Verge praised Google's development of a distinctive Pixel design language with the continuation of the Pixel 6 and Pixel 6a's camera bar. Both phones were well received after their launch. Julian Chokkattu of Wired and Max Buondonno of CNN Underscored lauded the phones' competitive pricing, displays, and camera capabilities. Dave LeClair of PCMag commended the Pixel 7's price and performance, while praising the Pixel 7 Pro's display and photography-related features. Gizmodo Florence Ion acclaimed the phones' camera system, and Marques Brownlee highlighted their software features. Mark Knapp and Kevin Lee of IGN viewed the phones as marginally superior to the Pixel 6 series, but praised Google's refinements nonetheless. The Verge Allison Johnson concurred, but found some of the new AI features "underwhelming". Lisa Eadicicco and Andrew Lanxon of CNET hailed the phones' incremental improvements as a reflection of Google's successful product formula, praising their design and features but criticizing the battery life. Engadget reviewer Sam Rutherford had a more positive experience with battery life, also praising the phones' upgraded designs. Mashable Alex Perry eulogized the larger phone's camera, but had reservations about the smaller Pixel 7 and lamented the loss of the Pixel 6 series' two-toned back design. Writing for TechRadar, Alex Walker-Todd applauded the Pixel 7's design and camera, while his colleague Philip Berne had mixed feelings about the Pixel 7 Pro's software features.
Commercial reception
During Google parent company Alphabet's quarterly earnings investor call in February 2023, Google and Alphabet CEO Sundar Pichai touted the Pixel 6a, 7, and 7 Pro as Google's "best-selling generation of phones", allowing Google to gain market share in all of its markets. Additionally, a survey conducted by market research firm Wave7 in January 2023 further indicated that the Pixel 7 series, especially the Pro model, experienced stronger numbers than the Pixel 6 series. The Pixel 7 series, alongside the Pixel 6a, were principally responsible for the Pixel's 87 percent year-over-year growth globally. Data from the International Data Corporation showed that Google sold around 10 million Pixel phones during the 2022–2023 fiscal year.
Future
The Pixel 7 and Pixel 7 Pro were succeeded by the Pixel 8 and Pixel 8 Pro in October 2023.
References
Further reading
External links
Pixel 7 (archived)
Pixel 7 Pro (archived)
Made by Google 2022 (archived)
Android (operating system) devices
Discontinued flagship smartphones
Foxconn
Google hardware
Google Pixel
Mobile phones introduced in 2022
Mobile phones with 4K video recording
Mobile phones with multiple rear cameras | Pixel 7 | [
"Technology"
] | 1,859 | [
"Discontinued flagship smartphones",
"Flagship smartphones"
] |
70,060,173 | https://en.wikipedia.org/wiki/Sum%20of%20four%20cubes%20problem | The sum of four cubes problem asks whether every integer is the sum of four cubes of integers. It is conjectured the answer is affirmative, but this conjecture has been neither proven nor disproven. Some of the cubes may be negative numbers, in contrast to Waring's problem on sums of cubes, where they are required to be positive.
Partial results
The substitutions , , and in the identity
lead to the identity
which shows that every integer multiple of 6 is the sum of four cubes. (More generally, the same proof shows that every multiple of 6 in every ring is the sum of four cubes.)
Since every integer is congruent to its own cube modulo 6, it follows that every integer is the sum of five cubes of integers.
In 1966, proved that any integer that is congruent neither to 4 nor to −4 modulo 9 is the sum of four cubes of integers. For this, he used the following identities:
These identities (and those derived from them by passing to opposites) immediately show that any integer which is congruent neither to 4 nor to −4 modulo 9 and is congruent neither to 2 nor to −2 modulo 18 is a sum of four cubes of integers. Using more subtle reasonings, Demjanenko proved that integers congruent to 2 or to −2 modulo 18 are also sums of four cubes of integers.
The problem therefore only arises for integers congruent to 4 or to −4 modulo 9. One example is
but it is not known if every such integer can be written as a sum of four cubes.
18x±2 case
According to Henri Cohen's translation of Demjanenko's paper, these identities
together with their complementary identities leave the 108x±38 case, proving the proposition. He also proves the 108x±38 case in his paper.
See also
Sums of three cubes
Notes and references
Diophantine equations
Unsolved problems in mathematics | Sum of four cubes problem | [
"Mathematics"
] | 413 | [
"Unsolved problems in mathematics",
"Mathematical objects",
"Equations",
"Diophantine equations",
"Mathematical problems",
"Number theory"
] |
70,061,567 | https://en.wikipedia.org/wiki/Topical%20drug%20delivery | Topical drug delivery (TDD) is a route of drug administration that allows the topical formulation to be delivered across the skin upon application, hence producing a localized effect to treat skin disorders like eczema. The formulation of topical drugs can be classified into corticosteroids, antibiotics, antiseptics, and anti-fungal. The mechanism of topical delivery includes the diffusion and metabolism of drugs in the skin. Historically, topical route was the first route of medication used to deliver drugs in humans in ancient Egyptian and Babylonian in 3000 BCE. In these ancient cities, topical medications like ointments and potions were used on the skin. The delivery of topical drugs needs to pass through multiple skin layers and undergo pharmacokinetics, hence factor like dermal diseases minimize the bioavailability of the topical drugs. The wide use of topical drugs leads to the advancement in topical drug delivery. These advancements are used to enhance the delivery of topical medications to the skin by using chemical and physical agents. For chemical agents, carriers like liposomes and nanotechnologies are used to enhance the absorption of topical drugs. On the other hand, physical agents, like micro-needles is other approach for enhancement ofabsorption. Besides using carriers, other factors such as pH, lipophilicity, and drug molecule size govern the effectiveness of topical formulation.
History
In ancient times, human skin was used as a layer for self-expression by painting cosmetic products on it. They used those products as a protection for their skin from the sun and dry environment. Later on in 2000 BCE, the Chinese used topical remedies that wrap in bandages to treat skin diseases. The contact between these topical remedies and skin deliver its therapeutic effect on the skin. The newer development of topical drugs occurred between 130 and 200 AD. This development was made by Claudius Galenus, a Greek physician. He first loaded the herb medication to Western medicine and formulated it as cream. More recently in the 1920s, some observations were made when applying topical skin, such as to determine its systemic effects. In 1938, Zondek successfully managed urogenital infections after applying chloroxylenol on the skin by the use of disinfectant in ointment form. After some years, observations were made from various experiments. These experiments led to the development of skin toxicology in the mid-1970s, including symptoms like irritation, skin inflammation, and skin photo-toxicity upon application of topical drugs. After the development of toxicology, a mathematical model was also created for skin diffusion coefficient formulated by Michaels. This formulation suggests how they related to the aqueous solubility and partition coefficient in skin.
Skin absorption
Skin layers
The human body's largest organ is the skin layers, which protects against foreign particles. Human skin contains several layers, including the subcutaneous layer, the dermis, the epidermis, the stratum corneum, and the appendages. Each of these layers have an effect on the absorption of topical drug. When the topical drug is applied to the skin, it must pass via the stratum corneum, which is the outermost skin layer. Stratum corneum's function includes prevention of water loss in skin and inhibit the penetration of foreign molecules into the dermal layers. Hence, it also prevents the hydrophilic molecules to get absorbed into the skin since it is made out of bilayered lipids. With this barrier, stratum corneum affects the permeability of topical drugs. Another part of the skin is called the appendages, and it is known as the “shortcut” for topical drug delivery. The shortcut pathway allows the drug molecules to first pass the stratum corneum barrier via hair follicles.
Diffusion
When drugs are applied to skin topically, the drug molecules will undergo passive diffusion. This process occurs down the concentration gradient when drug molecules move to one area to another region. Diffusion is described by a mathematical equation. The drug molecule (J), known as flux and it represents the entry of topical drug molecules across the skin membrane. The skin membrane is the area (A) for the topical drug molecules to travel across. The skin membrane thickness is known as (h) in the expression, and it determines the diffusion path length. The (C) is the concentration of the diffusing substance across the skin layers and the (D) is the diffusion coefficient. The expression illustrates the transportation of topical drug molecules across the stratum corneum membrane through diffusion.
Diffusion expression:
Mechanism
Upon application of the topical drug on the skin, it will diffuse to the outer layer of the skin, known as stratum corneum. There are three routes possible for the drugs to cross the skin. The first route is through the appendages. It is known as the "first cut" where the drug molecules will be partitioned into the sweat gland to bypass the stratum corneum barrier. If the drug molecules is not transported via the "first cut", it is usually remains in the stratum corneum's bilayered lipids, where the drug molecules transport through either the transcellular route or paracellular route into the deeper area of the skin like subcutaneous layer. For the paracellular route, it means that the solutes transport via the junction between the cell. When the topical drug molecules transport via the paracellular route, it needs to travel across the stratum corneum, which is a highly fat region, but between the cells. On the other hand, the topical drug molecules may travel through the transcellular route. This route allows molecules to be transported via the cell. Transcellular route transports the drug molecule into the bilayered lipid cells found in stratum corneum. Inside of the bilayered lipids in the stratum corneum is a water-soluble environment, and the drug molecules will diffuse through these bilayered lipids into deeper area of the skin. During the transportation of the topical drug molecules, it can bind to the keratin that exists as one of the skin components in the stratum corneum.
Skin metabolism
The activities of skin metabolism are commonly occurring on the skin surface, appendages, the stratum corneum, and the viable epidermis. This process comprises phase one hydrolysis, reduction, and oxidation, also known as functionalization phase. If phase one is insufficient to metabolize the drugs, phase two conjugation reaction occurs. This phase includes glucuronidation, sulfation, and acetylation. It is found that phase two activities are lower than phase two in the skin. One common example is thearylamine-type hair dye, after it is applied topically, it will undergo metabolism in the skin through enzyme N-acetyltransferase, thus resulting in a N-acetylated metabolite. These metabolic enzymes cause the loss of topical drug activities, thus reducing its bioavailability. They may eventually form atoxic compound that reaches to the systemic circulation and causes damage to the skin layers. The longer the topical drug remains in the skin, the greater amount of it will be metabolized by the underlying enzymes. To reduce such an effect, the topical drug needs to remain on the skin for a shorter period of time. Also, certain amount of topical molecules needs to be applied to the skin and cause metabolic enzymes saturation.
Factors affect topical absorption
The amount of topical drug molecules being delivered to the skin is affected solely by the physicochemical properties of the topical drug. The first factor is the weight of the drug molecule. The smaller of the drug molecular weight or particle size, the higher rate of its diffusion and absorption into the skin. The second factor is the lipophilicity of the drug molecules, since the three pathways for absorption are quite lipophilic. The higher lipophilicity of it, the easier of the drug molecules to be absorbed when compared to the hydrophilic drug molecules. The third parameter is the pH level of the skin. The pH of the skin layers are basic, hence basic topical drugs will be absorbed better than acidic topical drugs. These factors are vital to determine the permeability of topical drug delivery.
Skin permeability enhancers
Colloidal System
Colloidal system is one of the techniques used for topical drug delivery into the skin and functions as skin permeability enhancers. They are known as carriers and can be classified into nanoparticles, liposomes, and nanoemugel.
Liposome
Liposomes contain a bilayer of phospholipids in a sphere shape that may exist as one or more than one bilayer of phospholipids. With this structure, its function is to trap hydrophilic or lipophilic drug molecules within the spherical bilayers. The hydrophilic drug molecule sticks to the hydrophilic head since it is polar and favours water. On the other hand, the lipophilic drug molecules will be entrapped in the phospholipid tails of the bilayer due to its lipophilic nature. With these mechanisms, liposomes will behave like carriers and carry the lipophilic or hydrophilic drug molecules into the stratum corneum and release them into deeper layers of the skin by interacting with the bilayers lipids found in stratum corneum. The Use of liposome as carrier enhances the overall permeability of topical drug into the skin to reach the target site. For example, a drug like amphotericin B, is used to treat fungal infections. The drug is loaded into liposome and this carrier enhances the penetration of amphotericin B into the skin, regardless of its molecular weight.
Nanoemulgel
Nanoemulgel is another type of enhancer for delivery of topical drugs into the skin. The formulation process for nanoemulgel is produced by incorporating the nanoemulsion into a gel matrix. The gels are made out of aqueous bases and it allows for a more rapid release of drugs through dissolution. The use of nanoemulgel enhances patient compliance because the use of gel is less greasy than traditional cream or ointment, hence there is less incident in skin irritation. Nanoemulgel increases the topical drug bioavailability by inserting the lipophilic drug molecules into the oil droplet of the nanoemulgel and it will travel through the skin layers. With its high dissolution rate, the nanoemulgel produces a high concentration gradient toward the skin, thus allowing for a rapid uptake of oil droplet into the stratum corneum. Also, the surfactant being incorporated into the nanoemulgel has the ability to penetrate through the bilayer lipid by interrupting the hydrogen bond between the lipid in the skin to further enhance its permeability. In terms of treatment, the use of nanoemulgel is against cancer cells and useful in skin cancer. Also, the formulation of nanoemulgel with methoxsalen is used to treat psoriasis. The carrier enhances both the penetration and accumulation of methoxsalen in the skin layers.
Physical Agents
Micro-needles
Micro-needle belongs to the physical enhancer to improve absorption of topical drug molecules into the skin. It is known as ‘poke and patch’ because it uses tiny needles and stick into the skin across the stratum corneum. These tiny needles ensure that they will not contact the nerve endings or cutaneous blood vessels under the skin, hence they can be removed easily from the skin. There are several types of micro-needle, the first one is solid micro-needles. The solid micro-needles are used to project into the skin. Once the needles are removed after insertion, the topical drugs are applied to skin. This enhances the ability of drugs to diffuse across the viable epidermis. The second type is the dissolvable micro-needle. These types of needles are composed of materials that allow them to dissolve after poking into the skin, hence no need to remove the needles after injection. The third type of micro-needle is the swell-able micro-needles, which consist of hydrogel. After poking its needle into the skin, it allows the skin interstitial fluid diffuse into the micro-needles, thus it will swell to diffuse the drug molecules across the skin. It is found that micro-needles are safe and effective in enhancing skin permeability.
References
Routes of administration
Drug delivery devices | Topical drug delivery | [
"Chemistry"
] | 2,584 | [
"Pharmacology",
"Drug delivery devices",
"Routes of administration"
] |
65,704,644 | https://en.wikipedia.org/wiki/Ranitidine%20bismuth%20citrate | Ranitidine bismuth citrate - drug, which has antisecretory and bactericidal action.
Group affiliation: H2-histamine receptor blocker.
Shape
Physical
Pills. The film-coated tablet contains ranitidine bismuth citrate 400 mg; in a blister 14 pcs., in a box 1, 2 or 4 blisters.
Chemical
N- / 2 - /// 5 - / (Dimethylamino) methyl / -2-furanyl / methyl / thio / ethyl / -N'-methyl-2-nitro-1,1-ethenediamine bismuth citrate.
Pharmacological properties
Antiulcer, which is mediated by two active ingredients. Ranitidine - a blocker of H2-histamine receptors, suppresses basal and stimulated, day and night gastric acid secretion, reducing both the volume of its secretion and the concentration hydrochloric acid and pepsin are secreted. Bismuth citrate in vitro has a bactericidal effect on Helicobacter pylori, a protective effect on the gastric mucosa.
Indications
Stomach ulcer and duodenal ulcer, including those associated with Helicobacter pylori (in combination with amoxicillin or clarithromycin ohm).
Prospects for repurposing
Ranitidine bismuth citrate may also be effective against coronavirus and SARS-CoV-2, since it exhibits low cytotoxicity and is able to protect cells from infection with the SARS-CoV-2 virus, with a selectivity index of several times higher than that of remdesivir a. This is due to the fact that it inhibits the activity required for viral replication helicase Nsp13 SARS-CoV-2 due to irreversible displacement of zinc (II) ions from enzyme and bismuth ions ( III)
Contraindications
Hypersensitivity, acute porphyria, chronic renal failure (CC less than 25 ml / min), childhood (up to 14 years), pregnancy, lactation.
Side effects
From the digestive system: gastralgia, diarrhea or constipation, increased activity of "hepatic" transaminases, hepatitis (hepatocellular, cholestatic or mixed, with or without jaundice, usually reversible), acute pancreatitis. From the side of the cardiovascular system: decrease BP, bradycardia, AV block, chest pain, asystole (with injection). On the part of the hematopoietic organs: anemia, leukopenia, thrombocytopenia, agranulocytosis, pancytopenia, aplasia bone marrow. From the nervous system and sensory organs: headache, dizziness, depression, hallucinations, in severe and elderly patients - impaired visual perception (associated with a violation of accommodation); violation of taste; tremor, confusion. From the side of the musculoskeletal system: arthralgia, myalgia. Allergic reactions: pruritus, urticaria, angioedema, bronchospasm, anaphylactic shock, anaphylactoid reactions. Others: gynecomastia in men.
Overdose. Symptoms: neuro- and nephrotoxicity. Treatment: gastric lavage, symptomatic therapy. Ranitidine and bismuth can be removed from the bloodstream by hemodialysis a.
Method of administration and dosage
Inside, regardless of food intake, 2 times a day (morning and evening). In the treatment and prevention of benign gastric and duodenal ulcers, as well as for the eradication of Helicobacter pylori and the relief of concomitant symptoms of dyspepsia, the following combination therapy regimens are used. Within 7 days - 3 drugs: Scheme 1. 2 times a day - ranitidine bismuth citrate 400 mg, clarithromycin 500 mg, metronidazole 400 mg or amoxicillin 1 g. Scheme 2. 2 times a day - ranitidine bismuth citrate 400 mg, clarithromycin 250 mg, metronidazole 400 or 500 mg or tinidazole 500 mg. Scheme 3. Ranitidine bismuth citrate 400 mg 2 times a day, metronidazole 500 mg 3 times a day, tetracycline 500 mg 4 times a day. Scheme 4. 2 times a day - ranitidine bismuth citrate 400 mg, tinidazole 500 mg, amoxicillin 1 g. Within 14 days - 2 drugs: Scheme 5. Ranitidine bismuth citrate 400 mg 2 times a day and clarithromycin 500 mg 2 or 3 times a day. Scheme 6. Ranitidine bismuth citrate 400 mg 2 times a day and amoxicillin 500 mg 4 times a day. To stimulate regeneration processes in ulcerative diseases of the stomach and duodenal ulcer - 800 mg / day (for 2 doses) for 28 days. For the treatment of duodenal ulcers - 800 mg / day (for 2 doses) for 4 weeks (can be extended up to 8 weeks if necessary); with a stomach ulcer - 8 weeks.
Special instructions
Before starting therapy, the possibility of gastric ulcer malignancy is excluded, since ranitidine bismuth citrate can mask the symptoms of carcinoma of the stomach. Patients with mild or moderate renal impairment with CC of at least 50 ml / min do not require dose adjustment. In elderly patients with CC more than 25 ml / min, the dose is not changed. Dose changes in liver failure are not required, since ranitidine and bismuth are excreted mainly by the kidneys. H 2 -histamine receptor blockers should be taken 2 hours after taking itraconazole a or ketoconazole a to avoid a significant decrease in their absorption. H 2 -histamine receptor blockers can counteract the effects of pentagastrin a and histamine a on gastric acid-forming function, so use H 2 blockers within 24 hours prior to the test -histamine receptors are not recommended. H 2 -histamine receptor blockers can suppress the cutaneous reaction to histamine, thus resulting in to false negative results (it is recommended to discontinue the use of H 2 -histamine receptor blockers before performing diagnostic skin tests to detect an immediate allergic skin reaction). As with the use of other medicines containing bismuth, darkening of feces and blackening of the tongue are possible. The drug is taken with food or regardless of food intake.
Interaction
Clarithromycin increases the absorption of ranitidine. The concentration of clarithromycin in plasma does not change when combined with ranitidine bismuth citrate. With the simultaneous administration of ranitidine bismuth citrate with antacids, the absorption of bismuth does not change. Medicines that depress the bone marrow increase the risk of neutropenia. Reduces the absorption of itraconazole and ketoconazole due to an increase in pH in the gastrointestinal tract.
Notes
References
H2 receptor antagonists
Bactericides | Ranitidine bismuth citrate | [
"Biology"
] | 1,592 | [
"Bactericides",
"Biocides"
] |
65,704,821 | https://en.wikipedia.org/wiki/Giorgio%20Carta%20%28engineer%29 | Giorgio Carta is an Italian chemical engineer.
Biography
Carta completed a bachelor's of science degree in chemical engineering at the University of Cagliari in 1980, then pursued doctoral study in the subject at the University of Delaware. Upon obtaining his PhD in 1984, Carta joined the University of Virginia faculty, where he was later named Lawrence R. Quarles Professor of Chemical Engineering. He became a member of the organizing committee for the PREP International Symposium, Exhibition and Workshops on Preparative and Process Chromatography, Ion Exchange, Adsorption Processes and Related Separation Techniques in 1997, and has chaired or co-chaired the body since 2009. Carta was elected to fellowship of the American Institute for Medical and Biological Engineering in 2002, and was similarly honored by the American Institute of Chemical Engineers in 2007.
References
Living people
Italian expatriates in the United States
20th-century Italian engineers
21st-century Italian engineers
University of Virginia faculty
University of Delaware alumni
University of Cagliari alumni
Expatriate academics in the United States
Chemical engineering academics
Italian chemical engineers
Fellows of the American Institute of Chemical Engineers
Year of birth missing (living people)
Fellows of the American Institute for Medical and Biological Engineering | Giorgio Carta (engineer) | [
"Chemistry"
] | 243 | [
"Chemical engineering academics",
"Chemical engineers"
] |
65,704,869 | https://en.wikipedia.org/wiki/KELT-10 | KELT-10, also known as CD−47°12635, is a sun-like star in the southern constellation Telescopium. It has an apparent magnitude of 10.62, making it readily visible in telescopes, but not to the naked eye. Parallax measurements from the Gaia spacecraft place the star at a distance of 617 light years; it is currently receding with a radial velocity of .
KELT-10 has a stellar classification of G0 V, indicating that it is a yellow dwarf like the Sun. However, the object is 7% more massive and 21% larger. It is also slightly hotter, with an effective temperature of compared to the Sun's of . The star has a similar age, with an age of 4.5 billion years and more luminous, having a luminosity 40% greater. KELT-10's iron abundance is 123% that of the Sun, consistent with a planetary host. However, this amount is poorly constrained.
Planetary System
In 2015, a "hot Jupiter" orbiting the star was discovered by the KELT-South telescope. KELT-10b orbits at a distance 10 time closer than Mercury orbits the Sun, and is bloated due to its orbit.
References
G-type main-sequence stars
Telescopium
TIC objects
Planetary systems with one confirmed planet
Durchmusterung objects | KELT-10 | [
"Astronomy"
] | 285 | [
"Telescopium",
"Constellations"
] |
65,705,586 | https://en.wikipedia.org/wiki/Proof%20of%20personhood | Proof of personhood (PoP) is a means of resisting malicious attacks on peer to peer networks, particularly, attacks that utilize multiple fake identities, otherwise known as a Sybil attack. Decentralized online platforms are particularly vulnerable to such attacks by their very nature, as notionally democratic and responsive to large voting blocks. In PoP, each unique human participant obtains one equal unit of voting power, and any associated rewards.
The term is used in for cryptocurrency and blockchains as a parallel to proof of work, proof of stake, and other consensus mechanisms which attempt to distribute voting power and rewards to participants proportionately to an investment of resources.
Background
The problem of Sybil attacks using many virtual identities has been recognized for decades as a fundamental challenge for distributed systems that expect each human user to have only one account or identity. CAPTCHAs attempt to rate-limit automated Sybil attacks by using automated Turing tests to distinguish humans from machines creating accounts or requesting services. Even when successful in this goal, however, CAPTCHAs allow one human to obtain multiple accounts or shares of a resource simply by solving multiple CAPTCHAs in succession, and thus do not satisfy the one-per-person goal in proof of personhood. Aside from CAPTCHAs allowing people to obtain multiple users, there are additional complications. Many users who are visually impaired or have learning disabilities may struggle to complete the puzzles. Additionally, some recently developed AI has succeeded in solving the CAPTCHA issue.
Distributed systems could require users to authenticate using strong identities verified by a government or trusted third party, using an identity verification service or self-sovereign identity system for example, but strong identification requirements conflict with the privacy and anonymity, and increase barriers to entry. One approach proposed to create anonymous but one-per-person credentials for use in distributed systems is pseudonym parties, in which participants gather periodically at in-person events and leverage the fact that humans can physically be in only one place at a time.
In 2014, Vitalik Buterin proposed the problem of creating a "unique identity system" for cryptocurrencies, which would give each human user one and only one anti-Sybil participation token. In 2017, the term "proof of personhood" was proposed for an approach based on pseudonym parties.
Approaches
A variety of approaches to implementing proof of personhood have been proposed, some in experimental deployment.
In-person events
The approach originally proposed by Borge et al. was to use in-person pseudonym parties as a basis to create anonymous one-per-person tokens periodically without requiring any form of identity verification. The encointer project adapts this approach by asking participants to meet in small groups simultaneously at randomly-chosen places, to verify each other's physical presence.
One drawback of this approach is the inconvenience to participants of going to designated physical locations at specific times, especially for participants with conflicting responsibilities at those times. Another issue is the challenge of organizing federated pseudonym parties in multiple locations simultaneously while allowing each group to verify that all other groups are organized honestly without inflating the number of digital credentials they issue.
Social networks
Another approach, related to the PGP Web of Trust, relies on users forming a social network to verify and attest to each other's identities. UniqueID incorporates biometric verification into the social network approach.
One criticism of the social network approach is that there is no straightforward way for a participant to verify that a social connection has not created other Sybil identities connected to and verified by other, disjoint sets of social contacts. A related challenge is that Sybil detection based on graph analysis make certain assumptions about the behavior of a Sybil attacker, and it is not clear that real-world social networks satisfy these assumptions. Finally, graph-based Sybil detection algorithms tend to be able to detect only large, densely-clustered groups of Sybil nodes in a social network, leaving small-scale attacks difficult or impossible to distinguish by graph structure alone from legitimate users' connectivity structures.
Strong identities
Another approach requires participants to have verified identities, but to hide or anonymize those identities in subsequent use. One criticism of this approach is the privacy and surveillance risks inherent in such databases, especially biometric databases, and the level of trust users must place in the verification service for both Sybil protection and privacy of their identity information. Other critics highlight that facial recognition systems fail on a global scale due to insufficient facial entropy.
Apple, who are known for implementing a facial recognition feature into the iPhone, attempts to protect users' privacy with the Secure Enclave. The mathematical structure of a user's face captured by the TrueDepth camera does not leave the user's device, increasing the privacy and protection of personal information. However, some concerns have been raised in regards to the level of security of the facial recognision on the devices. For example, there have been cases where family members were mistakenly recognized as their siblings.
Even with decentralized privacy protections, a criticism of this approach is the inconvenience and cost to users of verifying strong identities, and the risk of potential exclusion of users who do not readily have or cannot afford the requisite identity documents, are reluctant to participate due to privacy and surveillance concerns, or are wrongly excluded by errors in biometric tests.
Crypto-biometrics
To resolve the security concerns over using biometrics for proof of human existence, only encrypting the biometrics data through cryptographic models is not enough. For this purpose, a new technique is proposed to use homomorphic encryption along with zero-knowledge proof to encrypt biometrics data in a way that original biometrics data never leaves the device of the user. Instead, the decentralized network is provided only with the relevant information to verify if a person is a real human being through liveness detection and is registered on a network.
Online Turing tests
Another proposed class of approach extends the CAPTCHA principle of using Turing tests to the unique human verification problem. The Idena network, for example, assigns participants to verify each other using flip tests.
Criticisms of this approach include the inconvenience to users of solving Turing tests, and whether artificial intelligence and deepfake technologies will soon be able to solve such tests automatically or convince real participants that a synthetic user is human during a verification interaction.
Use cases
One proposed use for proof of personhood is to ensure that voting power in permissionless consensus algorithms is widely distributed, and to avoid the re-centralization that has been observed in proof of work mining pools, and predicted in proof of stake systems.
Another proposed use is to facilitate democratic governance in decentralized online systems, including blockchains and cryptocurrencies, that wish to enforce a "one person, one vote" rule.
See also
Proof of authority
Proof of space
References
Turing tests
Cryptography
Cryptocurrencies | Proof of personhood | [
"Mathematics",
"Engineering"
] | 1,407 | [
"Cybersecurity engineering",
"Cryptography",
"Applied mathematics",
"Artificial intelligence engineering",
"Turing tests"
] |
65,706,578 | https://en.wikipedia.org/wiki/Suhail%20%28star%29 | Suhail, from , is the common name of a number of stars typically seen near the southern horizon.
It is part of the traditional names of three stars in the constellation Argo Navis.
Lambda Velorum, now officially named Suhail by the IAU Working Group on Star Names, was called in , but later shortened to just Suhail.
Gamma Velorum has the traditional name Al Suhail al Muhlif, also known as Regor.
Zeta Puppis, in the constellation of Puppis, is traditionally known as Suhail Hadar ().
In addition to these, the star Canopus (α Carinae), the second-brightest star in the night sky, is called in or in .
Argo Navis
Carina (constellation)
Puppis
Vela (constellation) | Suhail (star) | [
"Astronomy"
] | 169 | [
"Carina (constellation)",
"Vela (constellation)",
"Puppis",
"Constellations"
] |
65,708,925 | https://en.wikipedia.org/wiki/FactorDaily | FactorDaily is an Indian digital media publication founded in 2016 by Pankaj Mishra and Jayadevan PK. Mishra was formerly an Editor at TechCrunch and the Economic Times. The digital publication was launched with an intent to produce stories on the impact of technology on life in India.
History
FactorDaily began publishing in May 2016, with daily reported stories on technology, culture and life in India.
Prior to its launch, the company had raised $1 million in seed funding from Accel India, Blume Ventures, Girish Mathrubootham of Freshdesk, Vijay Shekhar Sharma of PayTm, and Jay Vijayan of Tekion.
Josey Puliyenthuruthel John, formerly Managing Editor at Business Today and National Corporate Editor at Mint, later joined the company as a Consulting Editor.
In January 2017, FactorDaily launched its first Podcast called The Outliers. The inaugural episode featured a conversation with Manish Sharma of Printo on his journey starting up.
Awards
The FactorDaily team won the Bengaluru Editors Lab 2017, a journalism hackathon organised by the Global Editors Network (GEN).
The story titled "India has 3,800 psychiatrists for 1.2bn people. Can tech step in to manage mental health?" won the first prize in the online category of the fifth Schizophrenia Research Foundation’s (SCARF) ‘Media for Mental Health’ awards.
The story titled 'The dark hand of tech that stokes sex trafficking in India', won the Stop Slavery media Awards by the Thomson Reuters Foundation for the year 2020.
References
Digital media | FactorDaily | [
"Technology"
] | 328 | [
"Multimedia",
"Digital media"
] |
65,708,939 | https://en.wikipedia.org/wiki/Evansia%20%28journal%29 | Evansia is a quarterly, peer-reviewed scientific journal, publishing research on issues in biology and environmental preservation related to lichenology and bryology, primarily in North America. It is published quarterly by the American Bryological and Lichenological Society (ABLS) and serves as the information bulletin of the ABLS. Articles are frequently popular or semi-technical rather than technical and intended for both amateurs and professionals. There are reports on local flora and presentations of techniques for studying and curating lichens, bryophytes, and hepatics. The ABLS named the journal in honor of Alexander William Evans.
References
Botany journals
Academic journals established in 1984
Quarterly journals
English-language journals
Bryology
Lichenology | Evansia (journal) | [
"Biology"
] | 149 | [
"Lichenology"
] |
65,708,989 | https://en.wikipedia.org/wiki/Wallemia%20mellicola | Wallemia mellicola is a xerophilic fungus of the phylum Basidiomycota, described in 2015 upon taxonomic revision of the species Wallemia sebi. A large amount of published research referring to W. sebi was likely actually performed on W. mellicola. An example of this is the sequencing of the W. mellicola genome, which was published under the name of W. sebi.
It has a worldwide distribution and is often found in habitats with low accessibility of water, from food preserved with high concentrations of sugar, salt or with drying, to dried straw and house dust. It has rarely been reported as the cause of human infections.
Like other species of the same genus, W. mellicola grows at low water activity, however it is not obligately xerophilic and can grow without additional solute in the growth medium. It grows at salt concentrations up to 24% NaCl, 13% MgCl2 and at temperatures between 10 °C and 34 °C.
W. mellicola has a compact genome of 9.8 Mb with few repeats, which is one of the smallest genomes in Basidiomycota and in Agaricomycota. Three gene family expansions that were observed in W. mellicola were considered significant, including heat shock protein, stress responsive alpha-beta barrel, and amino acid transporter, and they may be responsible for the survival W. mellicola at low water activity. Genes involved in High Osmolarity Glycerol signalling pathway were also found and were suggested to play an important role in the adaptation to osmotic stress. Wallemia mellicola also have a large number of transporters that allow it to survive in hyperosmotic conditions. After sequencing the genomes of additional 25 strains of W. mellicola, these was found to form a relatively homogeneous and widespread population. According to population genomic data the species is at least occasionally recombining. Two versions of a putative mating-type locus have been found in the sequenced genomes, each present in approximately half of the strains.
References
Wallemiales
Fungi described in 2015
Fungus species | Wallemia mellicola | [
"Biology"
] | 448 | [
"Fungi",
"Fungus species"
] |
65,709,137 | https://en.wikipedia.org/wiki/Ethinylestradiol/megestrol%20acetate | Ethinylestradiol/megestrol acetate (EE/MGA), sold under the brand name Volidan among others, was a combination of ethinylestradiol (EE), an estrogen, and megestrol acetate (MGA), a progestin, which was used as a birth control pill to prevent pregnancy in women. It was taken by mouth and contained 50 to 100 μg EE and 1 to 5 mg MGA per tablet. MGA-containing birth control pills were withdrawn after reports in the early 1970s of a high incidence of venous thromboembolism in association with the preparations.
See also
List of combined sex-hormonal preparations § Estrogens and progestogens
References
Abandoned drugs
Combined oral contraceptives | Ethinylestradiol/megestrol acetate | [
"Chemistry"
] | 165 | [
"Drug safety",
"Abandoned drugs"
] |
65,709,782 | https://en.wikipedia.org/wiki/Lesley-Ann%20L.%20Dupigny-Giroux | Lesley-Ann L. Dupigny-Giroux is the Vermont State Climatologist, president of the American Association of State Climatologists, Inc., and a professor of Geography at the University of Vermont.
Early life and education
Dupigny-Giroux was born in Trinidad. Her exploration of the small island gave her an early appreciation for place and geography, and their connections to history.
Dupigny-Giroux earned her Bachelor of Science degree from the University of Toronto in 1989, double majoring in physical geography and development studies. She earned both her Master of Science (1992) and Doctor of Philosophy (1996) degrees from McGill University. Her Master's degree was in climatology and hydrology, with a thesis on rainfall and runoff in drainage basins in Trinidad. Her doctoral degree was in climatology and geographic information systems (GIS), with a thesis on drought and rainfall over northern Brazil. Early in her graduate studies, Dupigny-Giroux spent a summer at the National Center for Atmospheric Research (1990) analyzing rainfall and runoff data using spectral analysis methods with Warren Washington and Harry van Loon and later (1992) participated in the National Oceanic and Atmospheric Administration (NOAA) colloquium on operational and environmental prediction, where she learned techniques in climate monitoring, weathering analysis, and hydrologic and oceanographic prediction.
Dupigny-Giroux worked as a research assistant and lecturer while at McGill University and taught at the Southern Illinois University at Edwardsville as an assistant professor (1996-1997) before joining the University of Vermont and becoming Vermont State Climatologist in 1997.
Research career
Dupigny-Giroux has served as Vermont State Climatologist and worked at the University of Vermont since 1997. She has authored more than 40 peer-reviewed publications and reports on hydrology, remote sensing, climate change and variability, extreme weather, and climate literacy.
Notable publications include work with the US Global Change Research Program, where Dupigny-Giroux served as contributing author on Climate Change in the Northeast: A Sourcebook, a technical input for the Northeast chapter of the third National Climate Assessment (NCA3), and as chapter lead of the Northeast chapter of the fourth National Climate Assessment (NCA4). The Northeast chapter of NCA4 included information on how climate change would affect rural economies, natural resources, and human health in the Northeast United States. She also served as lead editor of the book Historical climate variability and impacts in North America, which uses instrumental and historical data to reconstruct and analyze climate change in North America between the 17th and 19th centuries.
Dupigny-Giroux has also conducted research on North Atlantic Ocean tropical cyclones, including disaster mitigation research to reduce wind damage to residential infrastructure and construction in the Caribbean.
University of Vermont
At the University of Vermont, Dupigny-Giroux served as an Assistant Professor from 1997 - 2003, Associate Professor from 2003 - 2014, Chair of the Department of Geography from 2015 - 2018, and Professor beginning in 2014, with secondary appointments in Department of Geology, the College of Education & Social Services, and Rubenstein School of Environment & Natural Resources. She teaches courses in meteorology, climatology, physical geography, remote sensing, and land-surface processes.
Vermont State Climatologist
In her work as State Climatologist for Vermont, Dupigny-Giroux uses her expertise hydrology and extreme weather, such as floods, droughts, and storms, to keep the residents of Vermont informed on how climate change will affect their homes, health, and livelihoods. She assists other state agencies in preparing for and adapting to current and future impacts of climate change on Vermont's transportation system, emergency management planning, and agriculture and forestry industries. For example, she has published analyses of the impacts of climate change on the health of Vermont's sugar maples, a hardwood species of key economic and cultural importance to the state. As co-chair of Vermont's State’s Drought Task Force, she played a key role in developing the 2018 Vermont State Hazard Mitigation Plan.
Dupigny-Giroux served as Secretary for the American Association of State Climatologists from 2010-2011 and President Elect from 2019-2020. In June 2020, she was elected as President of the American Association of State Climatologists, which is a two-year term.
Climate literacy
In addition to her research on climate change, Dupigny-Giroux is known for her efforts to research and promote climate literacy. Climate literacy is an understanding of the influences of and influences on the climate system, including how people change the climate, how climate metrics are observed and modelled, and how climate change affects society. “Being climate literate is more critical than ever before,” Lesley-Ann Dupigny-Giroux stated for a 2020 article on climate literacy. “If we do not understand weather, climate and climate change as intricate and interconnected systems, then our appreciation of the big picture is lost.”
Dupigny-Giroux is known for her climate literacy work with elementary and high school teachers and students. She co-founded the Satellites Weather and Climate (SWAC) project in 2008, which is a professional development program for K-12 teachers designed to promote climate literacy and interest in the STEM (Science, Technology, Engineering and Mathematics) careers. Dupigny-Giroux is also a founding member of the Climate Literacy and Energy Awareness Network (CLEAN; formerly Climate Literacy Network), a community-based effort to support climate literacy and communication.
In a 2016 interview, Dupigny-Giroux stated: “Sharing knowledge and giving back to my community are my two axioms in life. Watching students mature and flourish in their four years with us is a great privilege and the best part about being a teacher-scholar here at UVM [University of Vermont].”
Diversity in climate sciences
Lesley-Ann Dupigny-Giroux is the co-founder of the Diversity Climate Network (D-ClimNet), which was funded by a National Science Foundation (NSF) award (2009-2013) to enhance diversity, equity, and inclusion in the field of climatology. The Diversity Climate Network aims to train the next generation of racially and gender diverse scientists by providing mentoring and networking opportunities to high school students interested in climate science or geoscience. In 2010, Dupigny-Giroux was the Franklin Visiting Scholar for Inclusion and Diversity Leadership at the University of Georgia.
Awards and recognition
Fellow - University of Vermont Gund Institute for Environment (2020)
University of Vermont, College of Arts & Sciences Scholar Teacher Award (2020) given to faculty who have consistently demonstrated the ability to translate their professional knowledge and skill into exciting classroom experiences for their students and who meet the challenge of being both excellent teachers and highly respected professionals in their own discipline
Fellow - American Meteorological Society (2020)
Association of Women Geoscientists (AWG) Professional Excellence Award for distinguished contributions in her profession (2018)
International Joint Commission, Lake Champlain-Richelieu River Study Board, US Chair, Public Advisory Board (2016-2017)
Fellow - Vermont Academy of Science and Engineering (2015)
Goddard College scholar of residence (2015)
Fellow - American Association of University Women (AAUW) Educational Foundation Shirley Farr (2003)
American Association for the Advancement of Science (AAAS) Women's International Science Collaboration (WISC) Program (2002)
References
External links
Faculty page
Hydrology
McGill University Faculty of Science alumni
University of Toronto alumni
Geosciences WikiProjects
University of Vermont faculty
Women climatologists
Trinidad and Tobago climatologists
Southern Illinois University faculty
Year of birth missing (living people)
Living people
21st-century Trinidad and Tobago women | Lesley-Ann L. Dupigny-Giroux | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 1,586 | [
"Hydrology",
"Environmental engineering"
] |
65,710,822 | https://en.wikipedia.org/wiki/Entomoculture | Entomoculture is the subfield of cellular agriculture which specifically deals with the production of insect tissue in vitro. It draws on principles more generally used in tissue engineering and has scientific similarities to Baculovirus Expression Vectors or soft robotics. The field has mainly been proposed because of its potential technical advantages over mammalian cells in generating cultivated meat. The name of the field was coined by Natalie Rubio at Tufts University.
Process
Entomoculture functions along the same principles as cellular agriculture in general. First, embryonic cells are derived from an insect. Embryonic stem cells are totipotent cells, meaning they retain the capacity to differentiate into any or all of the different kinds of specialized cells. These cells can either be taken from primary cultures (directly from the animal) or from cryopreserved secondary cultures. These stem cells are then immersed into a culture medium so that they can proliferate. Culture media consist of basal media, which is a composition of the various nutrients essential to cell growth. This mixture diffuses into the cell and once it consumes enough, it divides and the population multiplies. To optimize growth, this culture media is generally supplemented with other proteins and growth factors. Such additives are frequently produced by recombinant protein production—translating the respective genes into bacteria that are then fermented to produce several copies of the protein. The proliferated number of stem cells can then be seeded onto a scaffold to initiate a larger composition or can be placed directly into a bioreactor. The bioreactor replicates the environmental characteristics that would otherwise be emulated in vivo, including temperature and osmolarity, to promote cell differentiation into muscle tissue.In the bioreactor, stem cells undergo myogenesis—the differentiation into muscle tissue. This is a complex process involving the formation of founder cells and fusion-competent myoblasts. About 4–25 of the fusion-competent myoblasts then fuse with one founder cell to create multinucleated myofibers, which collectively become larval muscle.
When muscle tissue is developed in vivo, the larval muscle is destroyed during metamorphosis. A similar process transpires involving the adult muscle precursors, which use the old larval muscle as a template to create the mature muscle. However this process is not of significant relevance in in vitro cultivation, as development is stopped prior to metamorphosis.
Comparison to mammalian cell culture
In terms of cultured meat, entomoculture has mainly been proposed due to its potential advantages over mammalian cell culture. Such advantages can be ascribed to the differences in biology between the two cell types that enable insect cells to tolerate conditions more favourable for industrial production.
Temperature. Mammalian cells developing in vivo are incubated at 37 degrees Celsius. Simulating such a warm climate in a bioreactor requires energy inputs which thus increase production costs. Insect tissue can be grown to scale at room temperature or colder with little to no hindrance in cell development.
Culture conditions. As mammalian cells digest and metabolize glucose, they produce byproducts such as lactic acid which accumulate and acidify the cell's environment. The ability that cells have to uptake nutrients depends on the pH of the environment—it must be within a certain window for optimal growth. Lactic acid accumulation leads to inferior growth conditions for the cell. As such, the environment must be "rebalanced"—which is typically accomplished by replacing the entire culture medium as frequently as every 2–3 days. However, the saturated culture media may still contain viable nutrients, which makes the practise wasteful and expensive. Insect cells in part circumvent lactate production but are also tolerant to more acidic environments. When insect cell growth was compared at a pH of 5.5, 6.5 and 7.5, negligible difference was noted. As a result, insect cultures can have their media replaced at intervals as long as 90 days. This is compounded by the fact that insect cells do not deplete added nutrients as fast as mammalian cells. They consume triglycerides, glucose and proteins at a slower rate, suggesting that they have more efficient metabolic pathways. Additionally, insect cell cultures are typically contaminated with lipid cells called trophocytes or vitellophages, which are precursors to insect egg yolk cells. These cells are a natural source of fat that other insect cells can consume.
Osmolarity. Mammalian cells also require a relatively precise measure of carbon dioxide and oxygen to grow — as such, cultures are usually supplemented with an extra 5% carbon dioxide. Insects can go without this supplement.
Serum-free culture media. Culture media is an instrumental part of cellular agriculture and generating cultured tissue because it is effectively what allows scientists to begin with a relatively small sample of animal stem cells and end up with enough to constitute an entire tissue. To proliferate, a cell does not only require essential nutrients and macromolecules but also growth factors. When mammalian cells grow in vivo, these growth factors are supplied by the animal's blood. To replicate this, the culture medium usually consists of a basal mixture supplemented with extra growth factors. The basal medium makes up the bulk of the culture and contains most of the nutrients while the growth factors are added in trace amounts. As a result, the natural starting point is combining Fetal Bovine Serum (FBS) into the culture media.
FBS is somewhat controversial because it comes from the blood of a dairy cow fetus. The two issues with this is that it is a) reliant on animals, hence defeating the goal of cellular agriculture and b) expensive because it is so inaccessible. Additionally, from a scientific perspective, FBS is chemically undefined, meaning that its composition varies between animals. For the sake of research consistency, this is not desirable. The ideal culture medium is one that is simple, can stimulate proliferation, is unreliant on animals, is accessible and is cheap. However, because mammalian cells rely on a complex array of growth factors, finding a culture medium that satisfies all five of these criteria is an ongoing challenge. Insect cells on the other hand, are biologically simpler organisms than mammals. They contain a fluid called hemolymph rather than blood, so they do not rely on all the same growth factors as mammalian cells. Instead, insect cell medium typically uses a basal medium (such as Eagle's Medium, Grace's Insect Medium or Schneider's Drosophila Medium), which is supplemented with plant based additives such as yeastolate, primatone RL, hydrolysates, pluronic lipids and peptides.
Suspension cultures. When mammalian muscle cells grow in vivo, a fundamental part of their proliferation relies on their attachment to the extracellular matrix (ECM). To replicate this relationship, mammalian cells are usually cultured in adherent monolayers — cultures where the cells grow on a substrate in layers only one cell thick. This necessitates using bioreactors with a lot of surface area that, when scaled up to the industrial level, is unfeasible. The alternative is to use microcarriers, which are small pieces of material that float in the culture medium to increase the overall surface area the cells can attach to. This also introduces the need to vascularize. When mammalian cells are grown in adherent cultures, the cells not in direct contact with culture medium stop growing, forming necrotic centres. Unlike mammalian cells, insect cells are also able to grow unattached to anything — or in suspension cultures. This means that bioreactors do not need a large surface area, and can instead be produced in much more practical shapes.
References
Agriculture
Cellular agriculture | Entomoculture | [
"Engineering",
"Biology"
] | 1,588 | [
"Biological engineering",
"Cellular agriculture"
] |
65,711,212 | https://en.wikipedia.org/wiki/Defected%20ground%20structure | In printed circuit board manufacturing, a defected ground structure (DGS) is a purposefully-created defect on the ground plane of a printed microstrip board. It is typically created in the form of an etched-out pattern on the ground plane. DGS is a simplified form of an electromagnetic band gap (EBG) structure. This EBG is a periodic pattern featuring a band-stop property in microstrip transmission line and circuit applications, but the DGS comprises a single defect or a very limited number of defects with periodic/aperiodic configurations.
History
Kim et al. first conceived a limited form of EBG and coined the term ‘DGS’. They used a single unit of dumbbell-shaped defect beneath a microstrip line to use its stop-band characteristics within which it impedes the propagation of electromagnetic (EM) down the line over a range of frequencies. The compact feature and ease of implementation made it popular and several other shapes of DGS evolved very fast for various microwave circuit applications. Printed circuit filter is one of them. Apart from that, DGS has also been used in the circuits of an amplifier, rat-race coupler, branch-line coupler, Wilkinson power divider, etc. DGS was also employed underneath the feed lines to integrated microstrip antenna in order to filter out any unwanted harmonics.
Ideas for antenna applications
A new concept of its application to microstrip antenna was first reported in 2005 by Guha et al. The main focus was to suppress the cross-polarized radiations in a circular microstrip patch. DGS was strategically used to weaken the cross-pol generating higher-order TM21 mode. The important and necessary condition is that the deployed DGS should not influence or disturb the main resonance, i.e. the primary radiation mode. That work indeed introduced a non-resonant DGS and proved the concept. Subsequently, several advancements both in DGS type, geometry, and cross-polar performance have been achieved.
Yet another idea of patch-DGS integration has advanced the microstrip antenna array design. The issue of mutual coupling among the array elements can be reduced by integrating simple DGS- first reported in 2006. This technique has been matured to address the practical issue of "scan blindness" of large arrays.
This DGS-technique has been proved to be a very useful commercially viable tool to minimize two major issues like scan blindness and cross-polar radiations in phased arrays. New generation airborne and space-borne radars are now being developed using this DGS technology.
References
Antennas
Microwave transmission | Defected ground structure | [
"Engineering"
] | 535 | [
"Antennas",
"Telecommunications engineering"
] |
65,714,685 | https://en.wikipedia.org/wiki/Jennifer%20Nemhauser | Jennifer Lyn Nemhauser is an American biologist and a Professor of Developmental Biology at the University of Washington in Seattle, Washington. She specializes in synthetic biology, genomics, and signaling dynamics in plants.
Early life and education
Nemhauser was an undergraduate student at Wellesley College, where she majored in biological sciences. Her honors thesis considered the Arabidopsis thaliana Linoleate 9S-lipoxygenase (LOX1) promoter. After graduating, Nemhauser worked as a research assistant at the Whitehead Institute. She was a doctoral researcher in the group of Patricia Zambryski at the University of California, Berkeley. She moved to the Salk Institute for Biological Studies for her postdoctoral studies, where she worked in the laboratory of Joanne Chory. During her postdoctoral research she was first introduced to genomics, where she began to use genomic tools to better understand plant hormone signaling.
Research and career
In 2006, Nemhauser moved to Seattle, where she joined the University of Washington. Her research combines molecular genetics and synthetic biology. Primarily, Nemhauser looks to understand how the regulation of cellular function (e.g. division, differentiation and communication) allows for multi-cellular life. She develops novel tools to investigate the signaling dynamics of plants, including the transmission of the plant hormone auxin. Her data on auxins has been used as an example in an introductory biology textbook showing regulation of growth in plants. Nemhauser has extensively studied the model plant Arabidopsis thaliana to understand how seedlings adapt to their environments and how seedlings respond to light.
Select publications
Personal life
Nemhauser is also an active supporter of the arts. She sees art as a medium that helps scientists connect with the public. With funding from the NSF, Nemhauser brings local artists into her lab to produce art inspired by work in the laboratory. In 2016, artist Claire Cowie spent three months in Nemhauser's lab shadowing scientists and learning their stories. "Terminology I" is one of Cowie's works inspired by her residency in the lab. Extending beyond the lab, Nemhauser and her partner (Seattle painter Matthew Offenbacher) purchased seven works of art and donated them to the Seattle Art Museum, using Offenbacher's winnings from the 2015 Neddy Artist awards, stewarded by Cornish College. Nemhauser is also a member of 500 Queer Scientists and has described herself as being bi/pansexual.
References
External links
American women biologists
University of Washington faculty
Synthetic biologists
Wellesley College alumni
University of California alumni
American LGBTQ scientists
Year of birth missing (living people)
Living people
American women academics
21st-century American women | Jennifer Nemhauser | [
"Biology"
] | 558 | [
"Synthetic biology",
"Synthetic biologists"
] |
65,716,436 | https://en.wikipedia.org/wiki/Pip-Boy | The Pip-Boy is a fictional wearable computer in the post-apocalyptic Fallout video game franchise. Manufactured by RobCo Industries prior to the apocalyptic nuclear Great War, it is capable of numerous functions, depending on the model. In the Fallout games, it functions as a diegetic way for the player to access the menu and manage their inventory, as well as equip certain items when necessary.
The Pip-Boy has been named one of the most iconic tools of Fallout and video games as a whole, and is praised for its design, as well as being compared with real wearable computers. In 2015, Bethesda released a replica Pip-Boy as part of a limited run of collector's editions of Fallout 4. This replica could house a smartphone, allowing the player to control their in-game device through a phone application. A Pip-Boy 2000 Mark VI replica D.I.Y kit was sold to commemorate the release of Fallout 76.
Characteristics
In the Interplay Fallout titles, the Pip-Boy serves as a stand-in for a menu screen. In the Bethesda titles, it is attached to the player character's arm and is looked at from a first-person perspective. The newer Pip-Boy models contains a map, quest tracker, a radio and a light-up screen function, serving as a sort of flashlight.
Development
Leonard Boyarsky, one of the lead designers of Fallout at Interplay, stated that he designed the Pip-Boy more towards his personal preference for "old, clunky technology" than any trend towards retrofuturism. The design was meant to seem like it "wasn't all that dependable" and "kind of hacked together" to show that "the world wasn't quite working". The user interface was meant to feel like an in-universe object, which was rare at the time. Anthony Postma, another Interplay designer, created the device's layout.
When Bethesda Softworks acquired the franchise, they increased its retrofuturistic themes. The redesigned Pip-Boy 3000 reflected the Streamline Moderne aesthetic, and looked sleeker and more polished, while still being relatively bulky. The new Pip-Boy also lacked the drawn mascot and exposed vacuum tubes of the original, in order to make it fit on the player's arm. These elements, however, make a return with Fallout 76's Pip-Boy 2000 Mark VI.
Reception
The Pip-Boy is a defining symbol of the Fallout series. Khee Hoon Chan of USgamer called the Pip-Boy "one of the most iconic tools in video game history", also stating that "the gadget's transformation is [...] emblematic of the series' divergence."
Much of the notoriety of the Pip-Boy has stemmed from its design, which has reflected the rise of later real-world wearable technology, and has also directly inspired the creation of functioning devices, both by fans and engineers. In 2010, Sean Hollister of Engadget compared the General Dynamics Itronix GD300 wrist-mounted GPS unit with the design of the Pip-Boy, saying, "no word on whether it will pick up post-apocalyptic radio stations as your mission unfolds". Similarly, the prototype wrist-mounted OLED screens developed by L-3 Display Systems for use in the United States Army were compared to Pip-Boys by Mike Fahey of Kotaku, who called them "just another fine example of PIPBoy technology in real life".
Fans have created numerous working replicas, utilizing technology such as Raspberry Pi. In 2014, a team of coders created a working replica for NASA's SpaceWearables: Fashion Designer to Astronauts' challenge. Replicas were also built for commercial sale, with ThinkGeek designing a "Deluxe Bluetooth Edition".
At Bethesda's first E3 media briefing in 2015, Todd Howard stated that Bethesda would be releasing a deluxe version of Fallout 4 containing a Pip-Boy, stating, "The Pip-Boy is an important part of Fallout and we love it so much we made a real one." However, this led to criticism when it was revealed that the Pip-Boy was a non-functional plastic enclosure for a smartphone, which would operate as the Pip-Boy's display. Timothy J. Seppala of Engadget called it a "glorified smartphone case", and said that while it was comfortable to wear, the Pip-Boy app functioned better on a larger screen, stating that while "cosplayers (and eBay resellers) will likely eat this up [...] once the novelty of the Pip-Boy wears off, the rest of us won't use it much." The limited availability of the Pip-Boy Edition was also criticized, as the replicas sold out almost as soon as they were put on sale, angering fans and quickly being listed on eBay by scalpers. However, as a replacement, some fans created 3D-printable Pip-Boys with space for a custom computer inside and a working tape deck. The fact that it did not work with larger phones was cited as an additional hurdle in getting the replica to function properly.
References
External links
Pip-Boy at Nukapedia, the Fallout Fandom wiki
Pip-Boy at the independent Fallout wiki
Fictional computers
Fallout (franchise)
Video game objects
Fictional elements introduced in 1997 | Pip-Boy | [
"Technology"
] | 1,119 | [
"Fictional computers",
"Computers"
] |
65,716,722 | https://en.wikipedia.org/wiki/Eganelisib | Eganelisib (USAN), codenamed IPI-549, is an experimental drug being investigated as a possible treatment for cancer. It is a highly selective phosphoinositide 3-kinase inhibitor, and thus works by inhibiting the enzyme PIK3CG, disrupting the PI3K/AKT/mTOR signaling pathway which plays important roles in the development of cancer.
Eganelisib is being developed by Infinity Pharmaceuticals. Early clinical trial results were published in September 2016. On September 29, 2020, it was granted Fast Track designation by the United States Food and Drug Administration (FDA) as a treatment for inoperable, locally advanced, or metastatic triple-negative breast cancer, combined with a checkpoint inhibitor and chemotherapy.
, five phase I/II clinical trials were ongoing in the United States, and one in Europe.
Eganelisib has also been explored for its potential use in the treatment of COVID-19 and MRSA. Early, pre-clinical in vitro studies published in 2024 suggested eganelisib's ability to inhibit PI3Kγ, an enzyme involved in myeloid cell movement into infected tissues, could reduce excessive immune system activity that can damage tissues. By inhibiting PI3Kγ, eganelisib may prevent myeloid cells from entering and damaging tissue in patients with COVID-19 or MRSA, thereby reducing inflammation and the risk of cytokine storms. The study also indicated eganelisib may inhibit the main protease (Mpro) protein of the SARS-CoV-2 virus, a crucial enzyme required for viral replication, potentially offering another therapeutic avenue against COVID-19.
References
Further reading
Catherine A. Evans*, Tao Liu, André Lescarbeau, Somarajan J. Nair, Louis Grenier, Johan A. Pradeilles, Quentin Glenadel, Thomas Tibbitts, Ann M. Rowley, Jonathan P. DiNitto, Erin E. Brophy, Erin L. O'Hearn, Janid A. Ali, David G. Winkler, Stanley I. Goldstein, Patrick O'Hearn, Christian M. Martin, Jennifer G. Hoyt, John R. Soglia, Culver Cheung, Melissa M. Pink, Jennifer L. Proctor, Vito J. Palombella, Martin R. Tremblay, and Alfredo C. Castro*. Discovery of a Selective Phosphoinositide-3-Kinase (PI3K)-γ Inhibitor (IPI-549) as an Immuno-Oncology Clinical Candidate ACS Med. Chem. Lett. 2016, 7, 9, 862–867; https://doi.org/10.1021/acsmedchemlett.6b00238
Antineoplastic drugs
Experimental drugs
Phosphoinositide 3-kinase inhibitors
Pyrazoles
Amines
Amides
Pyrimidines | Eganelisib | [
"Chemistry"
] | 612 | [
"Amines",
"Amides",
"Bases (chemistry)",
"Functional groups"
] |
65,716,952 | https://en.wikipedia.org/wiki/Puccinia%20cnici-oleracei | Puccinia cnici-oleracei is a plant pathogen that causes rust on species in the Asteraceae family.
See also
List of Puccinia species
References
External links
Index Fungorum
Fungal plant pathogens and diseases
cnici-oleracei
Fungus species | Puccinia cnici-oleracei | [
"Biology"
] | 56 | [
"Fungi",
"Fungus species"
] |
65,717,009 | https://en.wikipedia.org/wiki/Calliotoxin | Calliotoxin is a venom produced only by the blue coral snake of Southeast Asia. Calliotoxin is a short-chained neurotoxin that causes the victim's sodium channels to have delayed inactivation, causing them to remain open. This causes all of the neurons to fire at once and producing complete physical paralysis and a rapid death. There is no known antidote, though it is hoped that the venom may eventually become useful in creating painkillers for the management of chronic pain in humans.
References
Neurotoxins
Sodium channel blockers
Snake toxins | Calliotoxin | [
"Chemistry"
] | 119 | [
"Neurochemistry",
"Neurotoxins"
] |
65,717,922 | https://en.wikipedia.org/wiki/Evolveo | Evolveo is a Czech consumer electronics brand established in 2005. It is owned by Abacus Electric company based in České Budějovice, which has been a distributor in the field of information technology since 1992. At first, it operated only in Central Europe. Until 2013, it was named Evolve, and after entering English-speaking countries, it was renamed Evolveo.
Operations
The Abacus Electric company deals with the distribution of computer components, it is the largest distributor of computer cases in the Czech Republic and the largest Czech manufacturer of servers. Under its Evolveo brand, various consumer electronics products are manufactured. The brand's main products include rugged mobile phones, Smartwatches, fitness trackers, computer cases, keyboards, mice, Wireless speakers, headphones, Robotic vacuum cleaners, set-top boxes, antennas and other electrical material. The brand operates in more than ten countries.
References
External links
Evolveo.com/
Computer hardware companies
Consumer electronics brands
Mobile phone manufacturers
Czech brands
Czech companies established in 2005
Electronics companies established in 2005 | Evolveo | [
"Technology"
] | 210 | [
"Computer hardware companies",
"Computers"
] |
62,844,189 | https://en.wikipedia.org/wiki/Radio%20Corporation%20of%20America%20v%20China | Radio Corporation of America v China was a 1935 arbitration ruling, determining whether a 1928 concession granted by the government of China (specifically the Chinese National Council of Reconstruction) to the Radio Corporation of America (RCA), for operation of communication by a radio link between the United States and China, was exclusive, and could be considered to prohibit a similar concession granted in 1932 to the Mackay Radio and Telegraph Company. The arbitration ruling concluded that the additional concession was valid, because the RCA concession could not be considered exclusive.
Background
RCA was founded in 1919. At the time all radio and telegraphic traffic between China and the US, including official messages, were sent through either German radio or British cable links. Therefore, the US Navy lobbied a reluctant RCA to seek a concession for radio link to China (even though RCA's other Asian concessions were operating at a loss). RCA agreed, and in 1928 received a concession from China which began operation that year.
The Mackay Radio and Telegraph Company of California, also an American interest, signed a similar agreement with China in 1932. RCA claimed this was a breach of contract, on the grounds that its 1928 agreement gave it the exclusive right for the link.
Arbitration decision
The dispute was decided by a three-member arbitration panel, based in The Hague, under the provisions of the 1907 Convention for the Pacific Settlement of International Disputes. In 1935 it issued its opinion, concluding that the language of the RCA concession could not be construed as limiting the Chinese government's ability to authorize additional concessions:
The Chinese Government can certainly sign away a part of its liberty of action, and this also in the field of international radio-telegraphic communications, and of its cooperation therein. It can do so as well in an implicit manner, if a reasonable construction of its undertakings leads up to that conclusion. It will, as any other party, be bound by law and by any obligations, legally accepted. But as a sovereign government, on principle free in its restriction of its freedom of action, unless the acceptance can be ascertained distinctly and beyond a reasonable doubt.
References
Permanent Court of Arbitration cases
RCA
Concessions in China
Radio communications | Radio Corporation of America v China | [
"Engineering"
] | 434 | [
"Telecommunications engineering",
"Radio communications"
] |
62,844,407 | https://en.wikipedia.org/wiki/Envy-free%20pricing | Envy-free pricing is a kind of fair item allocation. There is a single seller that owns some items, and a set of buyers who are interested in these items. The buyers have different valuations to the items, and they have a quasilinear utility function; this means that the utility an agent gains from a bundle of items equals the agent's value for the bundle minus the total price of items in the bundle. The seller should determine a price for each item, and sell the items to some of the buyers, such that there is no envy. Two kinds of envy are considered:
Agent envy means that some agent assigns a higher utility (a higher difference value-price) to a bundle allocated to another agent.
Market envy means that some agent assigns a higher utility (a higher difference value-price) to any bundle.
The no-envy conditions guarantee that the market is stable and that the buyers do not resent the seller. By definition, every market envy-free allocation is also agent envy-free, but not vice versa.
There always exists a market envy-free allocation (which is also agent envy-free): if the prices of all items are very high, and no item is sold (all buyers get an empty bundle), then there is no envy, since no agent would like to get any bundle for such high prices. However, such an allocation is very inefficient. The challenge in envy-free pricing is to find envy-free prices that also maximize one of the following objectives:
The social welfare - the sum of buyers' utilities;
The seller's revenue (or profit) - the sum of prices paid by buyers.
Envy-free pricing is related, but not identical, to other fair allocation problems:
In envy-free item allocation, monetary payments are not allowed.
In the rental harmony problem, monetary payments are allowed, and the agents are quasilinear, but all objects should be allocated (and each agent should get exactly one object).
Results
A Walrasian equilibrium is a market-envy-free pricing with the additional requirement that all items with a positive price must be allocated (all unallocated items must have a zero price). It maximizes the social welfare.However, a Walrasian equilibrium might not exist (it is guaranteed to exist only when agents have gross substitute valuations). Moreover, even when it exists, the sellers' revenue might be low. Allowing the seller to discard some items might help the seller attain a higher revenue.
Maximizing the seller's revenue subject to market-envy-freeness
Many authors studied the computational problem of finding a price-vector that maximizes the seller's revenue, subject to market-envy-freeness.
Guruswami, Hartline, Karlin, Kempe, Kenyon and McSherry (who introduced the term envy-free pricing) studied two classes of utility functions: unit demand and single-minded. They showed:
Computing market-envy-free prices to maximize the seller's revenue is APX-hard in both cases.
There is a logarithmic approximation algorithm for the revenue in both cases.
There are polynomial-time algorithms for some special cases.
Balcan, Blum and Mansour studied two settings: goods with unlimited supply (e.g. digital goods), and goods with limited supply. They showed that a single price, selected at random, attains an expected revenue which is a non-trivial approximation of the maximum social welfare:
With unlimited supply, a random single price achieves a log-factor approximation to the maximum social welfare. This is true even with general (not monotone) valuations. For a single agent and m item types, the revenue is at least 4 log (2m) of the maximum welfare; for n buyers, it is at least O(log (n) + log (m)) of the maximum welfare.
With limited supply, for subadditive valuations, a random single price achieves revenue within 2O(√(log n loglog n)) of the maximum welfare.
In the multi-unit case, when no buyer requires more than a 1-ε fraction of the items, a random single price achieves revenue within O(log n) of the maximum welfare.
A lower bound for fractionally subadditive buyers: any single price has approximation ratio 2Ω(log1/4n).
Briest and Krysta focused on goods with unlimited supply and single-minded buyers - each buyer wants only a single bundle of goods. They showed that:
The problem is weakly NP-hard even when the wanted bundles are nested.
The problem is APX-hard even for very sparse instances.
There is a log-factor approximation algorithm.
Briest focused on unit-demand min-pricing buyers. Each such buyer has a subset of wanted items, and he would like to purchase the cheapest affordable wanted-item given the prices. He focused on the uniform-budget case. He showed that, under some reasonable complexity assumptions:
The unit-demand min-buying pricing problem with uniform budgets cannot be approximated in polytime for some ε> 0.
A slightly more general problem, in which consumers are given as an explicit probability distribution, is even harder to approximate.
All the results apply to single-minded buyers too.
Chen, Ghosh and Vassilvtskii focused on items with metric substitutability - buyer i’s value for item j is vi − ci,j, and the substitution costs ci,j, form a metric. They show that
With metric substitutability, the problem can be solved exactly in polynomial time.
When the substitution costs are only approximately a metric (i.e., they satisfy the triangle inequality approximately), the problem becomes NP-hard.
Wang, Lu and Im study the problem with supply constraints given as an independence system over the items, such as matroid constraints. They focus on unit-demand buyers.
Chen and Deng study multi-item markets: there are m indivisible items with unit supply each and n potential buyers where each buyer wants to buy a single item. They show:
A polytime algorithm to compute a revenue maximizing EF pricing when every buyer evaluates at most two items at a positive valuation (they use the Strong Perfect Graph Theorem).
The problem becomes NP-hard if some buyers are interested in at least three items.
Cheung and Swamy present polytime approximation algorithms for single-minded agents with limited supply. They approximate the revenue w.r.t. the maximum social welfare.
Hartline and Yan study revenue-maximization using prior-free truthful mechanisms. They also show the simple structure of nvy-free pricing and its connection to truthful mechanism design.
Chalermsook, Chuzhoy, Kannan and Khanna study two variants of the problem. In both variants, each buyer has a set of "wanted items".
Unit-demand min-buying pricing: each buyer buys his cheapest wanted item if its price is ≤ the agent's budget; otherwise he buys nothing.
Single-minded pricing: each buyer buys all his wanted items if their price is ≤ the agent's budget; otherwise he buys nothing.
They also study the Tollbooth Pricing problem - a special case of single-minded pricing in which each item is an edge in a graph, and each wanted-items set is a path in this graph.
Chalermsook, Laekhanukit and Nanongkai prove approximation hardness to a variant called k-hypergraph pricing. They also prove hardness for unit-demand min-buying and single-minded pricing.
Demaine, Feige, Hajiaghayi and Salavatipour show hardness-of-approximation results by reduction from the unique coverage problem.
Anshelevich, Kar and Sekar study EF pricing in large markets. They consider both revenue-maximization and welfare-maximization.
Bilo, Flammini and Monaco study EF pricing with sharp demands—where each buyer is interested in a fixed quantity of an item.
Colini-Baldeschi, Leonardi, Sankowski and Zhang and Feldman, Fiat, Leonardi and Sankowski study EF pricing with budgeted agents.
Monaco, Sankowski and Zhang study multi-unit markets. They study revenue maximization under both market-envy-freeness and agent-envy-freeness. They consider both item-pricing and bundle-pricing.
Relaxed notions of envy-freeness
Chen and Rudra consider a relaxation of Walrasian equilibrium, in which only the winners must be envy-free. The goal is to maximize the number of envy-free buyers.
Alon, Mansour and Tennenholtz and Amanatidis, Fulla, Markakis and Sornat consider a relaxation of market-envy-freeness, in which buyers are arranged in a social network, the prices should be similar only between nodes that are adjacent on the network, and the losers must not envy.
Flammini, Mauro and Tonelly consider a relaxation of market-envy-freeness in which each agent sees only the items of neighboring agents (on a given social network).
Elbassioni, Fouz and Swamy consider a relaxation of agent-envy-freeness, in which only the winners must not envy. They consider bundle-pricing.
Bérczi, Codazzi, Golak and Grigoriev explore the concept of dynamic pricing where prices can adapt to market conditions to maintain fairness among consumers, extending traditional notions of envy-freeness beyond static scenarios.
See also
Demand oracle - an oracle that is often used in algorithms for envy-free pricing.
References
Pricing
Fair division | Envy-free pricing | [
"Mathematics"
] | 1,993 | [
"Recreational mathematics",
"Game theory",
"Fair division"
] |
62,844,572 | https://en.wikipedia.org/wiki/Journal%20of%20Computing%20in%20Civil%20Engineering | The Journal of Computing in Civil Engineering is a bimonthly peer-reviewed scientific journal published by the American Society of Civil Engineers. It covers research specific to computing as it relates to civil engineering.
Abstracting and indexing
The journal is abstracted and indexed in Ei Compendex, Science Citation Index Expanded, ProQuest databases, Civil Engineering Database, Inspec, Scopus, and EBSCO databases.
References
External links
Civil engineering journals
American Society of Civil Engineers academic journals
Academic journals established in 1987 | Journal of Computing in Civil Engineering | [
"Engineering"
] | 105 | [
"Civil engineering journals",
"Civil engineering"
] |
62,844,657 | https://en.wikipedia.org/wiki/Guanitoxin | Guanitoxin (GNT), formerly known as anatoxin-a(S) "Salivary", is a naturally occurring cyanotoxin commonly isolated from cyanobacteria (specifically of the genus Anabaena). It is a potent covalent acetylcholinesterase inhibitor, and thus a potent rapid acting neurotoxin which in cases of severe exposure can lead to death. Guanitoxin was first structurally characterized in 1989, and consists of a cyclic N-hydroxyguanidine organophosphate with a phosphate ester moiety.
Toxicity and treatment
The main mechanism of action for guanitoxin is by irreversibly inhibiting the active site of acetylcholinesterase leading to excess acetylcholine in the parasympathetic and peripheral nervous systems; inducing poisoning via nicotinic and muscarinic cholinergic receptor stimulation. The clinical signs of high level guanitoxin exposure consists mainly of excessive salivation, lacrimation, chromodacryorrhea (in rats), urinary incontinence, muscular weakness, muscle twitching, convulsion, including opisthotonus, and respiratory distress and/or failure, and death.
Treatment of afflicted case by atropine has attested to suppress the muscarinic mediated toxicity; which prevents the namesake salivation that similarly reacts to prevent the toxin's other poisoning symptoms which include lacrimation, urinary incontinence and defecation. Atropine will not, however, counter another mechanism of the compounds toxicity as it also mediates a nicotinic adverse toxicity affecting muscle tremors, fasciculation, convulsions and respiratory failure.
Stability and degradation
Guanitoxin is generally labile. It decomposes rapidly in basic solutions, but is relatively stable in neutral or acidic solutions (pH 3-5). When stored at -20˚C, it slowly undergoes hydrolysis giving pre-guanitoxin N-oxide and monomethyl-phosphate, and more slowly, formation of pre-guanitoxin. Furthermore, air evaporation of guanitoxin solutions resulted in significant hydrolysis to pre-guanitoxin N-oxide.
See also
Anatoxin-a – a cyanotoxin that shares some clinical exposure signs, and also relates to the same cyanobacteria genera, but with a different chemical structure and toxic mechanism of action
Paraoxon – A synthetic pesticide with an analogous mechanism of action
Footnotes
References
Acetylcholinesterase inhibitors
Neurotoxins
Guanidine alkaloids
Organophosphates
Methyl esters
Cyanotoxins
Nitrogen heterocycles
Dimethylamino compounds
Bacterial alkaloids | Guanitoxin | [
"Chemistry"
] | 575 | [
"Neurochemistry",
"Alkaloids by chemical classification",
"Guanidine alkaloids",
"Neurotoxins"
] |
62,844,685 | https://en.wikipedia.org/wiki/Journal%20of%20Cold%20Regions%20Engineering | The Journal of Cold Regions Engineering is a quarterly peer-reviewed scientific journal published by the American Society of Civil Engineers. It covers civil engineering related to cold regions.
Abstracting and indexing
The journal is abstracted and indexed in Ei Compendex, Science Citation Index Expanded, ProQuest databases, Civil Engineering Database, Inspec, Scopus, and EBSCO databases.
References
External links
Civil engineering journals
American Society of Civil Engineers academic journals
Academic journals established in 1987
Glaciology journals | Journal of Cold Regions Engineering | [
"Engineering"
] | 103 | [
"Civil engineering journals",
"Civil engineering"
] |
62,844,809 | https://en.wikipedia.org/wiki/Journal%20of%20Energy%20Engineering | The Journal of Energy Engineering is a quarterly peer-reviewed scientific journal published by the American Society of Civil Engineers. It covers civil engineering as related to the production, distribution, and storage of energy.
Abstracting and indexing
The journal is abstracted and indexed in:
Ei Compendex,
Science Citation Index Expanded,
ProQuest databases,
Civil Engineering Database,
Inspec,
Scopus, and
EBSCO databases.
History
The journal has been known by several names:
Journal of the Power Division (1956-1978)
Journal of the Energy Division (1979-1982)
Journal of Energy Engineering (1983–present)
References
External links
Civil engineering journals
American Society of Civil Engineers academic journals
Academic journals established in 1956 | Journal of Energy Engineering | [
"Engineering"
] | 145 | [
"Civil engineering journals",
"Civil engineering"
] |
62,847,188 | https://en.wikipedia.org/wiki/Sijbren%20Otto | Sybren Otto (Groningen, 3 August 1971) is Professor of Systems chemistry at the Stratingh Institute for Chemistry, University of Groningen.
Career
Otto studied chemistry at the University of Groningen and in 1994, he received his Master's degree, focusing on physical organic chemistry and biochemistry, with the distinction cum laude. In 1998, he obtained his PhD, again with the distinction cum laude, from his supervisor Prof. Jan B.F.N. Engberts for his thesis entitled Catalysis of Diels-Alder reactions in water.
After his subsequent research in both the United States (in 1998, with Prof. Steven L. Regen) at Lehigh University and in the United Kingdom (first with Prof. Jeremy K.M. Sanders and then, from 2001 onwards, as a Royal Society University Research Fellow, both at the University of Cambridge), he was appointed assistant professor at the University of Groningen in 2009. In 2011, he was promoted to associate professor and in 2016, to full professor. From 2014 to 2019, he coordinated the master's degree programme in chemistry.
Alongside his work at the university, Otto is also one of the six principal investigators of the Dutch national gravity programme for functional molecular systems (FMS; €26 million, over 10 years, 2013–2023). The ambition of this programme is to gain control over molecular self-assembly. With this technology, nanomotors could be made, for example, or biomaterials to repair damaged bodily tissues.
Otto was the lead applicant and chair of the European Cooperation in Science & Technology (COST) Action CM1304 (Emergence and Evolution of Complex Chemical Systems), which united more than 95 European research groups. He is the chair of the Gordon Research Conference on Systems Chemistry 2020 and is editor-in-chief of the Journal of Systems Chemistry.
Otto is a member of the Royal Dutch Chemical Society (KNCV), fellow of the Royal Society of Chemistry and member of the American Chemical Society. He is member of the steering committee of the Origins Center. The Origins Center is a Dutch research platform for scientists who are involved in the key questions of the Dutch Research Agenda on the origin, evolution and future of life on Earth and in the universe. Otto is active on several fronts in both the Netherlands and abroad. Otto was elected a member of the Royal Netherlands Academy of Arts and Sciences in 2020.
Research
The research conducted by Otto and his research group is focused on various fields, varying from the origin of life (self-replicating systems and the Darwinian evolution thereof), to materials chemistry (self-synthesizing fibres, hydrogels and nanoparticle surfaces).
Specific interests include self-replicating molecules, foldamers, catalysis, molecular recognition of biomolecules and self-synthesizing materials (materials of which their self-assembly drives the synthesis of the molecules that assemble). The complex chemical mixtures that are designed, made and researched often display new properties that are relevant to understanding how new traits are able to arise in nature. The final goal of all of this research is the de novo synthesis of new forms of life via the integration of self-replicating systems with metabolism and compartmentalization. His 114 publications have been cited a total of 8,873 times by other scientists. His h-index is 51.
Grants and prizes
1999 Marie Curie Fellowship, University of Cambridge, United Kingdom.
2000 Junior Research Fellowship, Wolfson College, Cambridge, United Kingdom.
2001 Royal Society University Research Fellowship, University of Cambridge, United Kingdom.
2011 ERC Starting Grant (subsidy) from the European Research Council for research into: Self-replication in dynamic molecular networks
2013 Vici grant from the Dutch Research Council (NWO) for research into: the Darwinian evolution of molecules. (Vici grants are intended for excellent senior researchers who can demonstrably develop their own innovative research lines and who are suitable for coaching early-career researchers.
2013 Appointed as Fellow of the Royal Society of Chemistry.
2013 Visiting professor, University of Strasbourg, France.
2017 ERC Advanced Grant (subsidy) from the European Research Council.
2018 Visiting professor, Ludwig Maximilian University of Munich, Germany.
2018 Supramolecular chemistry prize of the Royal Society of Chemistry.
2020 Member of the Royal Dutch Academy of Science (link).
2023 ERC Synergy Grant (subsidy) from the European Research Council.
References
External links
Sijbren Otto's Staff page (University of Groningen website)
An overview of Sijbren Otto's work on making life in the lab
Overview of Otto's publications
Website of the Otto Research Group
Can we make life in the lab? Presentation by Sijbren Otto (YouTube)
''Self Replication: How molecules can make copies of themselves'' (YouTube)
1971 births
Living people
21st-century Dutch chemists
Members of the Royal Netherlands Academy of Arts and Sciences
Organic chemists
University of Groningen alumni
Academic staff of the University of Groningen
Scientists from Groningen (city) | Sijbren Otto | [
"Chemistry"
] | 1,023 | [
"Organic chemists"
] |
62,847,528 | https://en.wikipedia.org/wiki/John%20H.%20Lienhard%20V | John Henry Lienhard V (born 1961) is the Abdul Latif Jameel Professor of Water and Mechanical Engineering at the Massachusetts Institute of Technology. His research focuses on desalination, heat transfer, and thermodynamics. He has also written several engineering textbooks.
Childhood and education
Lienhard was born in 1961 in Pullman, Washington, where his father, John H. Lienhard IV, was a professor at Washington State University. His mother, Carol Ann Bratton, a violinist, was a member of the Washington State University String Quartet. The family moved to Lexington, Kentucky in 1967 when his father took a position at the University of Kentucky. Lienhard attended primary school and high school in Lexington.
Lienhard enrolled at the University of Kentucky when he was 16. He completed his bachelor's degree in engineering, summa cum laude, at the University of California, Los Angeles in 1982, and he took his master's degree in heat and mass transfer at UCLA in 1984 for research on Rayleigh–Bénard instability.
He then transferred to the University of California, San Diego, where he wrote his doctoral dissertation on wind tunnel measurements of strongly stratified turbulent flow, finishing in 1988. Lienhard's doctoral experiments encompassed Brunt–Väisälä frequencies up to 2.4 s−1 and required the development of hot-wire anemometry usable in the presence of large temperature fluctuations.
Career
Lienhard joined the mechanical engineering faculty of the Massachusetts Institute of Technology in 1988, immediately after graduating from UCSD. He has spent his entire professional career at MIT.
Lienhard's initial research at MIT focused on cooling by liquid jet impingement. This work included fundamental convection problems, droplet splattering, free-surface turbulence interactions, and pattern-formation in the hydraulic jump.
The thin boundary layer at a jet's stagnation point also provided an attractive avenue to high-heat-flux engineering. In 1993, Lienhard's group reported the highest
steady-state fluxes to that date removed from a macroscopic area, achieved using a high-speed water jet (≈40 kW/cm2). They later extended this approach to arrays of jets, allowing larger areas to be cooled at high flux. In 1998, they used an array of water jets at 46 m/s to remove 1.7 kW/cm2 by convection alone over areas of several cm2.
In the 2000s, Lienhard refocused his research on the problem of clean water supply and scarcity, particularly around desalination technologies. He approached this area through his background in thermal engineering and transport phenomena, making energy efficiency a central aim.
His group's desalination research has spanned a broad range of topics including humidification-dehumidification,
forward and reverse osmosis, membrane distillation,
produced water,
electrodialysis, nanofiltration, solar desalination,
and thermophysical properties.
The seawater thermophysical property database developed by his group has been widely used by other researchers.
Lienhard has written hundreds of peer-reviewed research publications and has been issued more than 35 US patents. The patents have facilitated several start-up companies formed by his former students.
Lienhard has been responsible for launching a number of major research programs at MIT. He was the founding director of the Center for Clean Water and Clean
Energy (2008–2017), a multi-million dollar research collaboration with King Fahd University of Petroleum and Minerals (KFUPM) involving dozens of faculty members at KFUPM and MIT.
He was the founding director of the Ibn Khaldun Fellowship program for Saudi Arabian Women,
which has brought dozens of PhD-level women to MIT for research collaborations. He is also the founding director of the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) at MIT.
J-WAFS funds diverse research on water and food, across all of MIT's schools, to address the needs of a rapidly growing population on a changing planet.
Lienhard is a committed educator, recognized with awards for teaching and mentoring. He has written textbooks on measurement and instrumentation, on heat transfer, and on thermal modeling. He has long collaborated with his father on A Heat Transfer Textbook. In 2001, they made the decision to distribute the work primarily as an ebook, one of the first textbooks to adopt this format. The ebook, which is free of charge, has since been downloaded hundreds of thousands of times across the world.
Selected awards and honors
Lienhard has received a number of honors and awards, including the following:
Donald Q. Kern Award of the American Institute of Chemical Engineers (AIChE), 2022
Fellow of the American Society of Thermal and Fluid Engineers, elected in 2021
Edward F. Obert Award of the American Society of Mechanical Engineers (ASME), November 2019
Chief Guest (commencement speaker) of the Convocation of the Indian Institute of Technology Ropar, December 2018
Fellow of the American Association for the Advancement of Science (AAAS), elected in 2018
John R. Freeman Lecturer, Boston Society of Civil Engineers, 2016
Heat Transfer Memorial Award of the American Society of Mechanical Engineers (ASME), November 2015
Technical Communities Globalization Medal of the American Society of Mechanical Engineers (ASME), November 2012
J. P. Den Hartog Distinguished Educator Award of MIT, 2003
Fellow of the American Society of Mechanical Engineers (ASME), elected in 2000
Ralph R. Teetor Educational Award, Society of Automotive Engineers (SAE), 1992
Presidential Young Investigator Award, US National Science Foundation, 1988
In addition, Lienhard's research group has received many best paper, poster, and presentation awards for their work in desalination and heat transfer.
Textbooks
Thomas G. Beckwith, Roy D. Marangoni, and John H. Lienhard Mechanical Measurements, 5th edition, Addison-Wesley, Reading MA, 1993.
John H. Lienhard, IV and John H. Lienhard, V A heat transfer textbook, 3rd edition, Phlogiston Press, Cambridge, MA, 2001.
Thomas G. Beckwith, Roy D. Marangoni, and John H. Lienhard Mechanical Measurements, 6th edition, Prentice-Hall, Upper Saddle River NJ, 2007.
John H. Lienhard, IV and John H. Lienhard, V A heat transfer textbook, 4th edition, Dover Publications, Mineola NY, 2011.
Leon R. Glicksman and John H. Lienhard, V Modeling and approximation in heat transfer, Cambridge University Press, Cambridge, 2016.
John H. Lienhard, IV and John H. Lienhard, V A heat transfer textbook, 5th edition, Dover Publications, Mineola NY, 2019.
References
External links
MIT MechE People: John Lienhard
A Heat Transfer Textbook, 5/e, free ebook.
Abdul Latif Jameel Water & Food Systems Lab
Living people
1961 births
People from Pullman, Washington
People from Lexington, Kentucky
University of California, Los Angeles alumni
University of California, San Diego alumni
MIT School of Engineering faculty
American mechanical engineers
Fellows of the American Society of Mechanical Engineers
Fellows of the American Association for the Advancement of Science
Thermodynamicists | John H. Lienhard V | [
"Physics",
"Chemistry"
] | 1,489 | [
"Thermodynamics",
"Thermodynamicists"
] |
62,848,042 | https://en.wikipedia.org/wiki/Ordered%20Key-Value%20Store | An Ordered Key-Value Store (OKVS) is a type of data storage paradigm that can support multi-model database. An OKVS is an ordered mapping of bytes to bytes. An OKVS will keep the key-value pairs sorted by the key lexicographic order. OKVS systems provides different set of features and performance trade-offs. Most of them are shipped as a library without network interfaces, in order to be embedded in another process. Most OKVS support ACID guarantees. Some OKVS are distributed databases. Ordered Key-Value Store found their way into many modern database systems including NewSQL database systems.
History
The origin of Ordered Key-Value Store stems from the work of Ken Thompson on dbm in 1979. Later in 1991, Berkeley DB was released that featured a B-Tree backend that allowed the keys to stay sorted. Berkeley DB was said to be very fast and made its way into various commercial product. It was included in Python standard library until 2.7. In 2009, Tokyo Cabinet was released that was superseded by Kyoto Cabinet that support both transaction and ordered keys. In 2011, LMDB was created to replace Berkeley DB in OpenLDAP. There is also Google's LevelDB that was forked by Facebook in 2012 as RocksDB. In 2014, WiredTiger, successor of Berkeley DB was acquired by MongoDB and is since 2019 the primary backend of MongoDB database.
Other notable implementation of the OKVS paradigm are Sophia and SQLite3 LSM extension. Another notable use of OKVS paradigm is the multi-model database system called ArangoDB based on RocksDB.
Some NewSQL databases are supported by Ordered Key-Value Stores. JanusGraph, a property graph database, has both a Berkeley DB backend and FoundationDB backend.
Key concepts
Lexicographic encoding
There are algorithms that encode basic data types (boolean, string, number) and composition of those data types inside sorted containers (tuple, list, vector) that preserve their natural ordering. It is possible to work with an Ordered Key-Value Store without having to work directly with bytes. In FoundationDB, it is called the tuple layer.
Range query
Inside an OKVS, keys are ordered, and because of that it is possible to do range queries. A range query allow to retrieve all keys between two keys such as all keys that are fetched are ordered.
Subspaces
Key composition
One can construct key spaces to build higher level abstractions. The idea is to construct keys, that takes advantage of the ordered nature of the top level key space. When taking advantage of the ordered nature of the key space, one can query ranges of keys that have particular pattern.
Denormalization
Denormalization, as in, repeating the same piece of data in multiple subspace is common practice. It allows to create secondary representation, also called indices, that will allow to speed up queries.
Higher level abstractions
The following abstraction or databases were built on top Ordered Key-Value Stores:
Timeseries database,
Record Database, also known as Row store databases, they behave similarly to what is dubbed RDBMS,
Tuple Stores, also known as Triple Store or Quad Store but also Generic Tuple Store,
Document database, that mimics MongoDB API,
Full-text search
Geographic Information Systems
Property Graph
Versioned Data
Vector space database for Approximate Nearest Neighbor
All those abstraction can co-exist with the same OKVS database and when ACID is supported, the operations happens with the guarantees offered by the transaction system.
Feature matrix
See also
Key–value_database
Wide-column store
Multi-model database
References
Types of databases
Database theory
Databases
Associative arrays
Data management
Data analysis
NoSQL
Structured storage
Transaction processing | Ordered Key-Value Store | [
"Technology"
] | 763 | [
"Data management",
"Data"
] |
62,848,542 | https://en.wikipedia.org/wiki/Tantalum%28III%29%20chloride | Tantalum(III) chloride or tantalum trichloride is non-stoichiometric chemical compound with a range of composition from TaCl2.9 to TaCl3.1 Anionic and neutral clusters containing Ta(III) chloride include [Ta6Cl18]4− and [Ta6Cl14](H2O)4.
Formation
Tantalum(III) chloride is formed by reducing tantalum(V) chloride with tantalum metal. this is done by heating tantalum(III) chloride to 305 °C, passing the vapour over tantalum foil at 600°, and condensing the trichloride at 365 °C. If the condensing region is kept at too high a temperature, then TaCl2.5 deposits instead.
The trichloride can also be prepared by thermal decomposition of TaCl4, with removal of volatile TaCl5. TaCl5 can be vapourised leaving behind TaCl3.
"Salt-free reduction" of a toluene solution of TaCl5 with 1,4-disilyl-cyclohexadiene in the presence of ethylene produces a complex of TaCl3:
Properties
Above 500 °C, TaCl3 disproportionates further releasing TaCl5. TaCl3 is insoluble in room temperature water, or dilute acid, but dissolves in boiling water. A blue-green solution is formed.
Complexes
Tantalum(III) chloride can form complexes with some ligands as a monomer or dimer.
Complexes include Ta(=C-CMe3)(PMe3)2Cl3, [TaCl3(P(CH2C6H5)3THF]2μ-N2 and [TaCl3THF2]2μ-N2 (dinitrogen complexes).
As a dimer, complexes include Ta2Cl6(SC4H8)3 (SC4H8=tetrahydrothiophene). Ta2Cl6(SMe2)3, Ta2Cl6(thiane)3 and Ta2Cl6(thiolane)3 have a double bond between the two tantalum atoms, and two bridging chlorides, and a bridging ligand.
References
Tantalum compounds
Chlorides
Non-stoichiometric compounds | Tantalum(III) chloride | [
"Chemistry"
] | 500 | [
"Non-stoichiometric compounds",
"Chlorides",
"Inorganic compounds",
"Salts"
] |
62,850,634 | https://en.wikipedia.org/wiki/Circuit%20breaker%20analyzer | A circuit breaker analyzer is an instrument that measures the parameters of a circuit breaker.
In 1984, Megger patented a digital circuit breaker analyzer, controlled by a microprocessor. in 2020 few companies develop software to control circuit breaker analyzers from different devices such as computers, tablet computer, smartphones and others.
The following tests can be carried out on the circuit breaker: mechanical, thermal, dielectric, short-circuit.
The analyzer operates the circuit breaker under fault current conditions. After finishing the test of the breaker, the system measures currents, voltages and other main parameters of the breaker and through a set algorithm diagnoses the condition of the device under different conditions. The final result of the analysis give information about trip times, essential synchronism of the poles in the different operations of the circuit breaker.
Measured values
Timing measurements
Motion measurements
Coil currents
Dynamic resistance measurement (DRM)
Vibration analysis
Dynamic capacitance measurement
Static and dynamic resistance measurement
References
Electronic test equipment
Product testing
Measuring instruments | Circuit breaker analyzer | [
"Technology",
"Engineering"
] | 207 | [
"Electronic test equipment",
"Measuring instruments"
] |
62,852,112 | https://en.wikipedia.org/wiki/Gareth%20Brenton | A. Gareth Brenton FLSW. is a Welsh physicist and chemist known for his work in mass spectrometry.
Early life and education
Gareth was born in South Wales. He went on to attend the University of Wales at Swansea (now Swansea University) in the early 1970s. He received a Ph.D. in physics in 1979.
Career and research
Gareth took a position as Professor of Mass Spectrometry in Swansea University in 1982. He was Director of the Institute of Mass Spectrometry and Director of the EPSRC National Mass Spectrometry Facility at Swansea University until 2016.
Awards and honours
Gareth won the International Mass Spectrometry Society Curt Brunnée Award in 1994, and the BMSS Medal in 'Recognition of outstanding and sustained contributions to the British Mass Spectrometry Society in the promotion of Mass Spectrometry' in 2016. He was editor of Rapid Communications in Mass Spectrometry. Gareth was BMSS chairman between 2002 and 2004
In 2012, Gareth was elected a Fellow of the Learned Society of Wales.
Key publications
Beynon, J. H., and A. G. Brenton. An Introduction to Mass Spectrometry / by J.H. Beynon and A.G. Brenton. Cardiff: U of Wales, 1982. Print.
References
Year of birth missing (living people)
Living people
Welsh physicists
Mass spectrometrists
Alumni of Swansea University
Academics of Swansea University
Fellows of the Learned Society of Wales | Gareth Brenton | [
"Physics",
"Chemistry"
] | 305 | [
"Biochemists",
"Mass spectrometry",
"Spectrum (physical sciences)",
"Mass spectrometrists"
] |
62,852,640 | https://en.wikipedia.org/wiki/Chemical%20Workers%27%20Union%20%28Austria%29 | The Chemical Workers' Union (, GdC) was a trade union representing workers in the chemical industry in Austria.
The union was founded in 1945 by the Austrian Trade Union Federation. By 1998, it had 37,941 members. In 2009, it merged with the Metal-Textile-Food Union, to form PRO-GE.
Presidents
1945: Robert Pipelka
1949: Eduard Schwab
1962: Georg Grossauer
1975: Wilhelm Hrdlitschka
Josef Eder
2001: Wilhelm Beck
References
Chemical industry trade unions
Trade unions established in 1945
Trade unions disestablished in 2009
Trade unions in Austria
1945 establishments in Austria
2009 disestablishments in Austria | Chemical Workers' Union (Austria) | [
"Chemistry"
] | 135 | [
"Chemical industry trade unions"
] |
62,853,123 | https://en.wikipedia.org/wiki/Paleobiota%20of%20the%20Posidonia%20Shale | The Sachrang Formation or "Posidonienschiefer" Formation (common name the "Posidonia Shale") is a geological formation of southwestern Germany, northern Switzerland, northwestern Austria, southeast Luxembourg and the Netherlands, that spans about 3 million years during the Early Jurassic period (early Toarcian stage). It is known for its detailed fossils, especially sea fauna, listed below. Composed mostly by black shale, the formation is a Lagerstätte, where fossils show exceptional preservation (Including exquisite soft tissues), with a thickness that varies from about 1 m to about 40 m on the Rhine level, being on the main quarry at Holzmaden between 5 and 14 m. Some of the preserved material has been transformed into fossil hydrocarbon Jet, specially wood remains, used for jewelry. The exceptional preservation seen on the Posidonia Shale has been studied since the late 1800s, finding that a cocktail of chemical and environmental factors let to such an impressive conservation of the marine fauna. The most common theory is the changes in the oxygen level, where the different anoxic events of the Toarcian left oxygen-depleted bottom waters, with the biota dying and falling to the bottom without any predator able to eat the dead bodies.
Biological interactions
Several animal behaviours have been recovered on the Posidonia Shale. The Monotis-Dactylioceras bed is one of them, as it shows an accumulation of the bivalves Meleagrinella substriata and the ammonite Dactylioceras, that were the most abundant representatives of its group on the Altdorf region, and were probably washed to near epicontinental waters by a rapid event, or as result of a large succession of events. This assemblage has been compared with modern Brazilian coastal Mangroves and also linked to Tsunami events.
Related to the Ammonite fauna, on Holzmaden there have been found several empty shells of this cephalopods, with associated crustaceans inside. The original specimen was reported in 1995 and consisted on a possible member of the genus Paleastacus inside a chamber of a Harpoceras. Other epizoans are found related to the decayed Ammonite shells, such as Serpulid Annelids and Bivalves, creating what was denominated as "benthic islands" as reference at be isolated benthic units that attracted fauna. The Decapod is related to the family Erymidae, that are considered as possible bottom-dweller carnivorous or carrion feeders. The associated fossil has several spherical structures that had been interpreted as decapod coprolites, implying that the animal lived for a long period on the shell, and maybe changes on the bottom oxygen stopped the process. More recent studies had recovered new data about the inquilinism of decapods inside ammonites, this time, however, recovering three Eryonoidea lobsters together within a body chamber. The lobsters most likely used the ammonoid as some kind of shelter, where was excluded the possibility of transportation into the body chamber by bottom currents. There are several theories about the gregarious inquilinism showed by this specimens, such as that the shell was and ideal location to molt, as has not been proved to be corpses or molts; that the shell provided protection against predators; the decomposing soft body of the ammonoid was a source of food that attracted the decapods or that was used as a long-term shelter. One key aspect found was that the muddy bottom was not suitable for burrowing, implying that the decapods look for a different shelter due to being unable to make their own.
Beyond trace fossils, several vertebrate specimens show associations with crustacean exoskeletal remains such as GPIT-PV-31586 and SMNS 58389 (Pachycormus macropterus) with necrophagous interaction as well SMNS 55934 (Stenopterygius quadriscissus) or SMNS 95401 (Metopacanthus sp.).
The genus Clarkeiteuthis and its predatory behaviour, found associated with fishes of the genus Leptolepis. Based on the position of prey and predator, was suggested that the coeloid cephalopods caught and killed the fishes while the schools still in well-oxygenated waters and then descended into oxygen-depleted water layers where the cephalopod suffocated and died attached to its prey. The fish measured , while the coeloid 21 and it was measured by the fossilized arms of 14 specimens of coeloids that the hunting specimens arms where contracted over the fish, probably quickly killing it by cutting its spine.
Several Geotheutis have been reported with eumelanin preserved along with its ink sacs.
A specimen of Jeletzkyteuthis found on Ohmden has appeared predating a Parabelopeltis. The association of this 2 genera shows the predatory behaviour of this group when lived on Epicontinental seas, being rather different than extant Vampyromorphs.
A Pabulite (fossilized meal when it never entered the digestive tract) was recovered on Holzmaden, being composed by an associated Passaloteuthis laevigata with its arms embracing an exuvia of a crustacean. The own Belemnnite can be the remnant of a failed prey of a Hybodus, corroborating a possible tropic chain.
One of the most complex organism interactions on the Posidonia Shale where the crinoid megarafts, that group a wide variety of animals, creating large floating ecosystems, being the longest surviving communities to exist in the fossil record. The largest megaraft found measured , and is based on an Agathoxylon trunk, where different animals were attached. The first attached animals would have been the growing community of oysters, bivalves and crinoids, that would suppose and small weight to the raft about . The presence of this megaraft was in part possible due to the absence of marine wood worms, that destroy tree logs on less than 3 years along without the presence of modern raft wood predators (that appeared on the Bathonian) those rafts can last up to 5 years, being that the main reason the crinoids attached were able to reach huge sizes. Probably where also essential to distribute animals along the sea basins. Seirocrinus & Pentacrinites where various of the main crinoid colonizers of the floating rafts. Seirocrinus is the main representative of the pelagic crinoids, being among the tallest animals know, with a size of 26 m the largest documented specimen. The ecology of the genus is widely known, where is known that the smallest stems were among the first animals to colonize the rafts, with at least 2 generations of crinoids found per raft, where the hydrodynamic changes of the log influenced the settlement of the crinoids. It is believed that Seridocrinus had a seasonal reproduction, linked to the monsoonal conditions that sent new logs to the sea. The large crinoids would have feed on pelagic micronutrients, and afer fall on the bottom, all the colony would have died.
Thoracic cirripedes of the genus Toarcolepas became the oldest epiplanktonic cirripede known on the fossil record, probably motivated by the appearance of the giant crinoid rafts. It has been found in situ associated with fossil wood.
The shark Hybodus includes specimens with the gastric contents, being full of belemnnite fragments. That implied active predatory behaviour by the genus of several kinds of belemnnites, such as Youngibelus.
A Spienballen, a regurgitated mass composed of indigestible stomach contents had been found on the Holzmaden quarry. The Speinballen measures 285 mm length with a diameter of 160 mm, and consists of 4 members of the genus Dapedium (Dapediidae) and a jaw identified as Lepidotes (Semionotidae). The animals capable of it had been suggested as sharks like Hybodus, actinopterygians and several marine reptiles. Hybodus, being was able to reach nearly 3 meters long and with a dentition suitable to hunt fish, although its stomach contents suggest it is a mostly invertebrate hunter. Actinopterygians like Saurostomus grew up to 2 m long, and have been found with fishes, coeloids and ammonites in its stomach contents, however, not the fishes present on this Spienballen. Marine reptiles included marine crocodiles, such as Platysuchus or Pelagosaurus, associated to the fishes of the Speinballen, although are proven to have eaten gastroliths to improve buoyancy and digestion. Ichthyosaurs, whose diet is among the best studied of the Posidonia Shale, with Dapedium specimens in juvenile stomachs, along with coeloids. Temnodontosaurus, measuring between , would have been able to do such a large Speinballen. Plesiosaurs were disaccredited due to the study of its teeth, that proves a diet based on soft-body prey, such as fishes of the genus Leptolepis and coeloids. Dapedium and Lepidotes, with a heavy and solid squamation can be excluded.
A specimen of Pachycormus has been found with stomach contents that include hooks similar to the ones found on genera like Clarkeiteuthis.
Another specimen of Pachycormus macropterus preserves an ammonite inside its gut, likely swallowed by accident and directly responsible for the fish’s death.
SMNS 51144 (Saurostomus esocinus) was found with Chondrites isp. burrows in the abdominal cavity, what indicates a possible opportunistic scavenger. Other Chondrites isp. includes SMNS 17500 and MHH 1981/25 (Stenopterygius uniter) that can either suggest ichthyosaurs were preserved immediately below one such bioturbation horizon or scavenger association.
The know specimens of Toarcocephalus are evidence of successful predation events, as the head of one was isolated likely as product of a decapitation and other preserved within a regurgitated mass.
One of the most emblematic finds of the formation its that of a mother Stenopterygius giving birth living young, like the modern dolphins and marine mammals, being born with the tails first. Other specimens have been found with Embryos inside, but with the bones of them scattered, partly beyond the body limits of the mother. There have been various theories about this scenario: the bones of embryos had been deposited before the body of the adult went to the sea floor, covering the embryo bones and implying that the adult would not be the mother of the embryos. Another option is that a pregnant ichthyosaur on its last moments sank to the bottom and may have struggled for life, given untimely birth to some of the foetuses. Other option follows the presence of foetus bones outside the mother body, where a dead female sank to the bottom, with the water warm enough, helping the putrefaction gases to start to develop while the hydrostatic pressure was too high to be prevented by the body. Scavengers must have started eating from the dead body, until the chamber retaining the pressure was to thin and exploded. These theories where however contested after the study, where it was criticised the absence of the presence of the bottom-current activity in the epicontinental sea covering Central Europe during the Toarcian, pointing that the mother carcass should have been translated after it sank to the bottom floor, probably exploding or expelling its embryos first, that would be transported along.
Specimen SMNS 53363 (Eurhinosaurus?) from Aichelberg was found with two encrusted large oysters (Liostrea) on the right pterygoid, considered to be part of a reef stage over bones.
SMNS 80234 (Stenopterygius quadriscissus) represents another female with embryos, yet also shows ribs broken perimortem that can be either of intraspecific aggression or a predation attempt. This specimen has several taxa associated: ammonite aptychi and two ophiuroids (Sinosura brodiei) and a articulated echinoid (Diademopsis crinifera), indicating a short-lived deadfall community.
SMNS 81841 (Stenopterygius quadriscissus) represents one of the most clear examples of deadfall communities described in the formation: the skeleton is associated with serpulids surrounded by a mass of disarticulated ophiuroid remains, indeterminate echinoid tests, an isolated crinoid ossicle, the byssate bivalve Oxytoma inaequivalvis, the pectinid Propeamussium pumilus, Eopecten strionatis, Plagiostoma sp., Meleagrinella sp., "Cucullaea" muensteri, with the genera Parainoceramya dubia and Liostrea associated with the carcass. As many of this bivalves shown overgrowth likely the community persisted for some time. Fossil traces of Gastrochaenolites isp. attributed to mechanical bivalve borers are abundant implicating prolonged exposure of the skeleton on the seafloor.
SMNS 81719 (Stenopterygius uniter) includes Liostrea, Propeamussium pumilus, Plagiostoma sp. and Parainoceramya dubia, with other invertebrates found (?) not being part of the deadfall community, such as several ammonites and Parainoceramya valves stratigraphically below the specimen. This specimen includes also traces of scavenging activity, possibly by crustaceans.
SMNS 80113, (Stenopterygius triscissus) was found populated by Parainoceramya, a specimen of Eopecten strionatis and an unexpected specimen of the small infaunal lucinid Mesomiltha pumila, equivocal evidence for the sulfophilic stage.
Local ichthyosaur soft tissues include skin enough well preserved to infer coloration and appearance on the living animal, as well evidence for homeothermy and crypsis.
Gut contents of the local pterosaurs are know: Campylognathoides preserves hooks of the coeloid Clarkeiteuthis being the one of the few teuthophaous pterosaursy, while Dorygnathus preserves remains of Leptolepis.
Microbial activity
Non-fenestrate Stromatolite crusts formed in Aphotic deep-water environments during intervals of very low sedimentation are recovered in places such as Teufelsgraben, Hetzles. The Stromatolites of this region have evidence of live on a deeper shelf environment with a quietwater deposit which suffered repeated phases of stagnant bottom waters, where a depth water habitat developed, probably at more than 100 meters depth. There is a thin, southern widespread Stromatolite crust on the Top of the Sachrang Formation, called "Wittelshofener Bank", that has made rethink the depth of the major southern basin of the formation, where with the absence of phototrophic calcareous benthic organisms (probably due to the lack of light), shows the depth character of the basin. On the "Wittelshofener Bank" there is also the only occurrence of Ooids, presumably formed in the same deep-water environment.
Cyanobacteria
Rhizaria
Foraminifera
Dinoflagellata
Dinoflagellate cysts
The evolutionary burst of the Toarcian Dinoflajellates led the first appearance and rapid radiation of the Phallocystaceae (Susainium, Parvocysta, Phallocysta, Moesiodinium and related forms). This occurred at the time of a widespread Lower Toarcian bituminous anoxia-derived shale of the Posidonienschiefer Formation. Is recovered on the Posidonienschiefer, Pozzale, Italy, Asturias, Spain, Bornholm, Denmark, the Lusitanian Basin of Portugal, the Jet Rock Formation in Yorkshire and to the "Schistes Carton" in northern France. Whether there is a causal connection in this co-occurrence of Phallocystaceae and bituminous facies is a problem still to be resolved. This family has its acme in diversity and quantity in the latest Toarcian and became less important in the Aalenian.
Algae
Includes abundant variety of algae, such as the genus of colonial Green algae Botryococcus, or the unicellular algal bodies Tasmanites, and other small examples. Algae are a good reference for changes on the oxygen conditions along the Toarcian.
Algae Acritarchs
Haptophyta
Chlorophyta
Fungi
Fungal Spores, hypae and undeterminated remains are a rare element of the otherwise openmarine deposits of the Posidonienschiefer formation, but where recovered at Dormettingen. This fungal remains are composed mostly by indeterminate spores and indicate oxygenated environments and suitable transportation by rivers.
Incertae sedis
Ichnofossils
The major ichnological analyses of the Posidonian Shale come from Dotternhausen/Dormettingen, where the ichnogenus Phymatoderma formed the so-called Tafelfleins and Seegrasschiefer. The Tafelflein bed was deposited under anoxic bottom and pore water, where a recover of oxygen allow the Phymatoderma-producers return. The two organic-rich layers (Tafelfleins and Seegrasschiefer) are characterized by the dense occurrence of trace fossils such as Chondrites and Phymatoderma, done episodically due to the fall of the oxygen levels. The Coeval more nearshore Swiss deposits referred Posidonian Shale (Rietheim Member) hosted similar trace fossils asthose recovered on SW Germany. Tougth this setting apparently evolved faster to more oxic-to-dysoxic bottom waters.
At Unken, laminated deposits of red limestone suggest well oxygenated active waters (as lack shale), where high amounts of Chondrites are found.
Invertebrata
Porifera
In the non-bituminous facies located on Obereggenen im Breisgau (Shore of the Black Forest High), especially the lower semicelatum subzone, pyritized individual needles of silica sponges (Demospongiae and Hexactinellida) are found, rarely on pelagic layers to very often on the low depth marine deposits. They are usually associated with radiolarian stone cores. In Dusslingen and Reutlingen, these sponge needles could be barytized in phosphorites of the Haskerense subzone and are much more common here than in any other zone of the Lower Toarcian. These needles are absent in the bituminous horizons of the entire Lower Toarcian.
Increased amounts of Sponge needles (dominated by Hexactinellida) are also found on the arenaceous facies of the nearshore unit that is the Unken member, being the only section if its region hosts them, probably due to be an active and well oxygenated bottom. The location of this member as a possible bay on the south of the vindelician land probably allow to the development of more pre-Toarcian AOE conditions, hence the presence of biota otherwise rare on bituminous layers.
Annelida
Lophophorata
Bryozoa
Brachiopoda
Mollusca
Bivalvia
Gastropoda
Cephalopoda
Arthropoda
Cycloidea
Ostracoda
Malacostraca
Thoracica
Arachnida
Insecta
Insects are a common terrestrial animals that were probably washed into the sea due to monsoon conditions present on the Sachrang Formation.
Echinodermata
Echinoderm debris is pretty abundant on the shale-free Unken and Salzburg members, including Crinoid skeleton elements, also that of the Ophiurida; the Echinoids take their place, where really blossomed at that time. That's why Pedicellaria are observed very often.
Asterozoa
Echinoidea
Holothuroidea
Crinoidea
Vertebrata
Fishes
Chondrichthyes
Actinopterygii
Sarcopterygii
Amniota
Ichthyosauria
Inderminate specimens are known.
Plesiosauria
Sphenodontia
Testudinata
Crocodylomorpha
Pterosauria
{| class = "wikitable"
|-
! Genus
! Species
! Location
! Material
! Notes
! Images
|-
|
Campylognathoides
|
C. zitteli
C. liasicus
C. cf. C. liasicus
C. sp.
|
Banz
Altdorf
Mistelgau
Hondelange
Holzmaden
Ohmden
Dotternhausen
|
Complete Specimens
Partial Specimens
Isolated Remains
|
A Novialoidean Pterosaur, type genus of the family Campylognathoidea. Mark Witton suggests the construction of Campylognathoides''' extremely robust forelimbs, with proportionally long wing fingers, could be a specialization for a fast aerial lifestyle comparable to those of Falcons and mastiff bats, being more probably an insect & vertebrate hunter and living on nearshore environments.
|
|-
|Dorygnathus|D. banthensisD. cf.banthensisD. mistelgauensisD. sp.|
Banz
Altdorf
Mistelgau
Schandelah
Hondelange
Beienrode
Holzmaden
Ohmden
Dotternhausen
|
Complete Specimens
Partial Specimens
Isolated Remains
Non-mineralized tissues
Fur/Feather-like filaments
Possible coloration traces
|
A Rhamphorhynchinae Pterosaur. It is one of the best known Early Jurassic Pterosaurs. Unlike Campylognthoides, Dorygnathus was an oceanic hunter, with teeth disposed to catch marine prey, such as Belemnittes and several species of fishes. Dorygnathus mistelgauensis is considered a junior synonym until more data can be recovered from the specimen, held on a private collection.
|
|-
|
"Schandelopterus"
|
Indeterminate
|
Schandelah
|
Pelvis and several vertebrae.
|
A Novialoidean Pterosaur, probably a member of the family Campylognathoidea. Has been assigned to the genus Campylognathoides, although it is clearly different than any other pterosaur from the Sachrang Formation. The name "Schandelopterus" is invalid and lacks any study, assigned without species to refer to the specimen on private German Fossil Groups. The pelvis indicates a laterally, slightly upwardly directed orientation of the acetabula which does not support a bird-like bipedal locomotion of this pterosaur as has been suggested on the past.
|
|-
|Parapsicephalus|cf. P. purdoni|
Altdorf
|
Skull
|
A Rhamphorhynchinae Pterosaur. Has been assigned to the genus Dorygnathus. It has a really complete skull that can help to explain the status of the genus Parapsicephalus.
|
|-
|}
Dinosauria
Plantae
The macroflora of the Posidonia slate can be described as extremely poor in species. Apart from the remains of Horsetails, it is without exception the remains of coarse branches and fronds from gymnosperms, in which one has a certain can assume transport resistance. Remains of Ferns are completely missing, except for tall arboreal ferns (Peltaspermales). Mostly of the flora was reported from the area of Braunschweig. The major explanation for the flora could be that the plants in question are mono-or oligotypic stands on the edge of the waters that flow into the Posidonienschiefer sea, probably tear away in the course of flood events, easily fragmented during transport and wave waves, possibly especially in the occasional storm events postulated. In terms of taphonomy, this would result in a comparison with today's reed Phragmites'', which can form extensive stocks on the edge of shallower and slowly flowing waters ("Reed belts"). The Wood remnants clearly indicate one higher diversity of Coniferous flora in the delivery area than the remains of leafy branches. This fact is likely to be proportionate, similar to that frequent occurrence of charcoalized or gagged trunks, mostly of them are believed to be "driftwoods" that only take a long time drifting also suggests a frequent settlement with mussels and full-grown Sea Lilies. The deposition settings are at large distance from the nearest coastline (for southern Germany about 100 kilometers), making only plants strong to transportation able to resist enough to get deposited. At Irlbach and Kheleim, NE of Regensburg, where the Posidonienschiefer has its near mainland deposit with abundant sand, a rich deposit filled with plant remains of different kind (Seds, Reproductive organs, Leafs, Stems, Cuticles and wood) with traces of coal was recovered, however, it was never studied in depth. Of all the plant material expected only a few Bennetites leafs and two conifer branches with leaves where cited and none studied.
At the Austrian realm The sachrang Member was developed in the basinal area, while the Unken Member, sandwiched between red, often condensed limestones, represents the marginal facies. Due to be more marginal and connected with the southern Vindelician land, the most diverse palynological assemblages of the formation are found, transported from zonas with moldanuvian granites as proven by the feldspar accumulations.
Phytoclasts
Phytoclasts have been recovered from several sections on the formation, but only studied in depth from the Dotternhausen and specially Dormettingen. Here two kinds of Phytoclasts where recovered, opaque phytoclasts (charcoal, indicator of wildfire activity on nearby landmasses, indicator of seasonal alterations of the water column) and translucent phytoclasts (indicator of proximal landmasses with high availability of wood and other plant material, as well transport conditions). On the lowermost part of the section opaque phytoclasts are low (15% of the total organic matter) while translucent are incredibly abundant (40%), lowering its abundance to a 20-10% on the next section. The Exaratum Subzone is the only one with an inverse trend and more abundance of opaque phytoclasts. On the Bifrons level, both types reach between a 15% and a 30%, showing a rapid increase, to decrease on the end of the section to values of less than 10%. Opaque Phytoclasts, for a supposed marine deposit are relatively abundant on some sections, whose decreasing on others suggest (along with increasing levels of Kaolinite) an increased delivery of land plant material by rivers, from areas with wetter climate and less frequent fires, while its rise suggest the opposite, nearby continental setting with dry climate and continuous wildfire activity.
Palynology
Equisetaceae
Pteridospermatophyta
Bennettitales
Ginkgoales
Pinophyta
Fossil wood
Fossil Wood increases on the marginal Unken Member, with great amounts of logs and fragments of more than 1 m. Surface studies suggest relationships with the wood genera identified on the coeval Úrkút Manganese Ore Formation.
References
External links
Images of fossils in the Urwelt-Museum Hauff (Holzmaden)
Jurassic Germany
Posidonia | Paleobiota of the Posidonia Shale | [
"Biology"
] | 5,908 | [
"Mesozoic paleobiotas",
"Prehistoric biotas"
] |
62,853,650 | https://en.wikipedia.org/wiki/Corsia%20ornata | Corsia ornata is a species of flowering plant in the genus Corsia of the small family Corsiaceae, part of the monocot order Liliales. They are saprophytes (Myco-heterotrophs), lacking the ability to photosynthesise, being dependent on other organisms for their nutrition. The plant lives underground, sending up purplish stems above ground in order to flower. The leaves are reduced to scales. One of the six petal-like tepals named the labellum (a little lip), is specialised, being enlarged and hanging protectively over the reproductive organs. It was discovered in New Guinea in 1875, but has since been sighted in Queensland, Australia.
Description
The Corsiaceae lack chlorophyll and hence the ability to photosynthesise, instead being mycoheterotrophic (deriving nutrition as parasites on fungi). C. ornata, although perennial, only appears above ground when flowering, arising from short creeping rhizomes, reaching up to 25 cm in height. From the rhizomes, arise long, cylindrical and finely corrugated, unbranched and upright growing stems that are terete (almost circular in cross section) and narrowly ribbed. The above ground portion of the plant is a purplish to purplish-red in color. Leaves are reduced to acute (sharply pointed) sheath-shaped scales 1–2 cm in length, arranged alternately on the stem, with 3–5 nerves and similar bracts. The pedicels are glabrous and 2.5–4 cm long.
The upright individual flowers are terminal and stand on flower stems that are 2.5–4 cm long. Of the six tepals (in two whorls), five are linear, obtuse and pale yellow in colour, 11–13 millimeters long, one-nerved and hairless. The sixth, outer tepal, called the labellum, is either light yellow to light purple with a darker purple veins nerve or purplish brown. It is greatly enlarged (1.2–1.8 cm long, 1–1.6 cm wide) and cordate (heart-shaped) and obtuse, with a cordate base. The labellum initially surrounds the flower bud and, after opening, protects the other flower organs. It has a basal callus that is white, broadly shell-shaped, 2–3.5 mm long and around 2.5 mm wide, with a tip that is rounded or slightly acuminate, finely papillate at the margins with 8 or 9 lateral nerves that are variously branched and 16–18 short lamellae radiating from the basal callus that are distinctly pilose. At the base, the labellum overhangs the reproductive organs umbrella-like, the 1 mm long gynostemium (fused stamens and pistil). The 1.5 mm filaments are dark purple, the anthers dark purple to pink, 0.5 by 1 mm. The style is about 1.5 mm in length and the capsule 2.5–3.5 cm.
Taxonomy
Corsia ornata was first described by Odoardo Beccari in February 1875, and therefore bears his name (Becc.) as the botanical authority. It was the first species of the genus to be discovered and is therefore considered its type species. It is classified in the section Sessilis (named for their sessile labellum), the larger of the two sections of that genus, as one of 19 species.
Distribution and habitat
Corsia ornata is found at a number of widely spaced locations in the western part of New Guinea, particularly on Bird's Head Peninsula. One sighting in Queensland, Australia, makes it the only species found outside of New Guinea. Corsia ornata occurs in forests, between 400 and 2,100 m, in humus rich soils.
References
Bibliography
Books
Articles
Websites
External links
Corsiaceae
Parasitic plants
Parasites of fungi
Taxa named by Odoardo Beccari | Corsia ornata | [
"Biology"
] | 844 | [
"Fungi",
"Parasites of fungi"
] |
62,853,988 | https://en.wikipedia.org/wiki/Intermodal%20railfreight%20in%20Great%20Britain | Intermodal railfreight in Great Britain is a way of transporting containers between ports, inland ports and terminals in England, Scotland and Wales, by using rail to do so. Initially started by British Rail in the 1960s, the use of containers that could be swapped between different modes of transport goes back to the days of the London, Midland & Scottish Railway.
The transport of containers from ship to rail is classified by the UK government as Lo-Lo traffic (lift-on, lift-off). Volumes of intermodal traffic in the United Kingdom have been rising since 1998, with an expectation of further growth in the years ahead; by 2017, railfreight was moving one in four of containers that entered the United Kingdom. However, the movement of containers through the Channel Tunnel has been labelled as disappointing, but this has suffered myriad problems such as migrant issues and safety problems. Since privatisation of the railways in the 1990s, the market has grown from one initial operator (Freightliner), to four main operators, DB Cargo, Direct Rail Services and GB Railfreight, although other entrants have tried to run intermodal trains.
Many of the older terminals opened by British Rail have closed down, with the focus on strategic rail freight interchanges (SRFIs), which will focus on a wider area or region with good onward road, or water, transport links.
History
As a transfer container service, Freightliner was set up by British Rail as a separate company, with the first train running in November 1965. It was one of the reformative ideas put forward under the aegis of Richard Beeching as part of the rationalisation of the railway network in the 1960s. The idea of trains moving containers pre-dated the Beeching cuts, with some suggestions being put forward in the 1950s when the railway was under the control of the British Transport Commission. In the 1950s, British Rail ran a Condor service (an Anglo-Scottish container train that ran on two axle-wagons). The first service of Condor containers ran in March 1959, consisting of roller-bearing flat wagons that containers could be moved on and off with ease.
Even further back, the swapping of containers between modes of transport was utilised in the 19th century, when wooden containers were used, but after the railways were grouped in 1921, the London Midland & Scottish Railway (LMS) introduced this type of system with steel and aluminium containers.
Initially, the new Freightliner service was intended for the domestic movement of freight in containers between points in the Great Britain, with 16 terminals in operation in 1968, and Southampton and Tilbury under construction. However, in 1968 a London to Paris working was started which relied upon the Dover to Dunquerke train ferry, and by 1969, the service was linked into ports with a short-sea and a deep-sea service to other countries. By the end of the 1960s, liner trains (united transport) were carrying per year. By the end of 1978, this average was . In 1969, British Rail transferred ownership of Freightliner to the National Freight Corporation, but with BR supplying the wagons and locomotives. It was returned to BR in 1978.
By 1981, Freightliner was operating to 43 terminals, 25 of their own and 18 privately used locations. In 1982, the Port of Felixstowe was despatching three daily freight trains with containers on. In 1983, a second terminal opened (Felixstowe North), and between the two terminals, the amount of containers transhipped to and from rail was about 80,000 per year (20%). When a third terminal was opened in 2013 (named Felixstowe North, with the previous one being renamed Felixstowe Central), over 40 million TEUs (twenty-foot equivalent units) with 36 daily departures carrying containers were being handled. In 1986 and 1987, several terminals were closed, including four in Scotland (Aberdeen, Clydeport [Greenock], Dundee and Edinburgh) despite the potential for long-distance services from these terminals. British Rail deemed it more efficient to load containers at Coatbridge in Glasgow, and use electric traction south on the West Coast Main Line. Before the closures, Freightliner operated 35 terminals, including ports, compared with 19 under privatisation.
In 1988, Freightliner, Speedlink and Railfreight International, were amalgamated into one entity by British Rail, called Railfreight Distribution. A large section of the business that these three separate arms dealt with, were loss-making and the combined efforts were a way in which it was hoped to turn the businesses around. In 1992, it was assessed that Freightliner was making a 50% loss on its £70 million turnover, and the business was only serving nine locations. One of the problems causing this was that the deep-sea nature of the traffic carried was increasingly geared up to using the containers, which required gauge enhancement or specially adapted wagons to be carried on the British railway system.
The advent of the Channel Tunnel opening, led to a resurgence in container traffic terminals being opened. These were separated into sites away from the main railfreight business as operated between UK terminals and deep-sea ports such as Southampton and Felixstowe. New European freight terminals were built at Trafford Park in Manchester, Wakefield in West Yorkshire and Willesden in North West London. After this, the intermodal services in Britain could be subdivided into three streams; traffic to and from ports, Channel Tunnel traffic and domestic flows, of which much Anglo-Scottish traffic falls into the latter. This is a complete modal shift of the domestic nature of the Freightliner network as instigated in the mid 1960s which initially envisaged the market being domestic traffic dominating. One suggestion for the change in traffic origin has been that containers entering ports have a lower transport cost, as they only need onward road transport to their final destination, as opposed to the domestic traffic which needs to be road-hauled, railed and then road-hauled again.
The opening of Daventry International Rail Freight Terminal (DIRFT) in July 1997, heralded another new venture into the intermodal business. The site is located on the Northampton Loop of the West Coast Main Line, and close to the M1 motorway and the A45 road. The land had been designated as a "motorway orientated growth point" in 1978, and so was ideally situated for this type of interchange and delivery point for intermodal traffic. In 1997, services through the Channel Tunnel operated between Birmingham Landor Street, Daventry, Mossend, Seaforth, Trafford Park, Wakefield and Willesden in the United Kingdom, with terminals in Europe (Avignon, Barcelona, Lyon, Melzo, Metz, Muizen, Novara, Oleggio, Paris, Perpignan, Rogoredo and Turin). Even so, the volumes of intermodal traffic (and other commodities) shifted by railfreight through the channel Tunnel have been low compared with forecasted freight volumes. Whilst some problems range from the physical; migrants using the services to cross and at one point, invading the railway yard at Frethun, other problems have been strikes by French workers and fires in the tunnel which hampered pathing trains through.
Binliners and other traffic
Binliners are so named because they carry waste traffic in containers on the same type of wagons used to carry (freight)liner trains, (binliner being a portmanteau of the words bin and liner, so it sounds like a binliner).
The carrying of waste on the railway network, used to involve slow moving wagons, but in the 1970s, terminals began opening which would take compacted waste in containers direct to a landfill site. Whilst this traffic is not routinely grouped under the intermodal umbrella, its use of containers makes it an intermodal railfreight service, even if no onward road transport was used at the destination. Most binliners would run as block trains, but occasional special traffics would be railed to its final destination via the wagonload network, such as spent shot blast from Falmouth to Brindle Heath in Greater Manchester.
Most destinations were former quarrying or mining operations that had applications to take landfill. The main sites were at Forders in Bedfordshire, Calvert in Buckinghamshire, Appleford in Oxfordshire, Roxby Gullet in Lincolnshire and Appley Bridge in Greater Manchester. The main authorities using these sites were Greater London for Forders and Calvert, Avon for Calvert and Appleford, with Greater Manchester utilising first Appley Bridge, then Roxby when Appley Bridge was full. A similar operation was used on the Powderhall Branch in Edinburgh, which used to take compacted waste to exhausted quarry workings at the cement works at Oxwellmains in the Scottish Borders.
As an adaptation of the binliner trains, a landfill tax introduced in the 2010s, prompted some authorities to send their waste to be burnt in an energy from waste plant (EfW). Merseyside waste is burnt at the Wilton EfW plant, and some waste from London (loaded at Brentford) is burnt at the Severnside EfW plant.
Other commodities have been sent via containers such as desulphogypsum from power stations to gypsum processing plants, however, the containers are used solely for this purpose and not used as a generic swap container service available for different goods. Containers are used on the desulphogypsum traffic as it is sticky, so the use of hopper wagons would not work, and the use of tippler wagons would have been more expensive.
Rail versus other modes
In many areas of freight transport, rail loses out to road (or water transport), typically in smaller consists which has led to the demise of the wagonload network in Great Britain due to the small tonnages involved. Many containers are transferred between ports in Britain by water transport, mostly at sea using coastal shipping, but some on the canal or river systems. In 2018, the movement of Ro-Ro shipping traffic (which accounts for containers transported by sea, instead of the sea to land designation, which is Lo-Lo), equated to 3.3 billion tonne kilometres, in and around the United Kingdom. Even so, one of four containers that enter the United Kingdom, are then transported/part transported onwards by the use of railfreight.
Where rail transport has been beneficial, it has been over long distances such as Felixstowe to Coatbridge (Glasgow). Short distance flows are deemed uneconomic unless they can either be back filled, or be given a guaranteed full load on each train. An example of this was the Wilton to Doncaster Railport service in the 1990s/early 2000s, which carried containerised chemicals a distance of just . A similar service operates between Tees Dock and Doncaster iPort, which has an out and back run of only , and as such, the train and locomotive can be utilised twice in one day, making greater use of the resources. A service between Grangemouth on the Firth of Forth, and Elderslie in Renfrewshire, travelled a distance of only in the one direction. Whilst it normally loaded to 100% going eastbound (from Elderslie), it was only very lightly loaded westbound (from Grangemouth). However, its ability to deliver containers the short distance and avoid the congested M8, M80, M876 and M9 motorways, meant that it afforded customers a better transit time. The wagons and locomotive were used on additional freight services in between its intermodal run.
The movement of railfreight is measured in net tonne kilometres (NTK). The figures for intermodal railfreight between 1998 and 2018 are given below. Between 1975 and 1995, the NTK for intermodal traffic steadily decreased from 3.1 billion to 2.3 billion. Post 1996 (privatisation of the railfreight companies), this has seen a steady rise.
Operational enhancements
Constraints on the movement of containers across the UK rail network have been the loading gauge of the railway lines themselves, with most lines being able to accommodate containers. Only a few lines can handle the larger containers which has led to some lines being adapted to accept the larger gauge, while other routes have used 'pocket' wagons, where the container sits lower down in the wagon. Due to the steady year-on-year increase of intermodal traffic volumes, Network Rail, the owner and infrastructure manager of the UK rail network, has undertaken a series of schemes to allow easier pathing and the removal of gauge restrictions on core routes across the network.
Additionally, due to the increase in billion tonne kilometres travelled, and intermodal slowly gaining a larger market share of railfreight tonnage moved, there have been several key network enhancement operations to enable smoother running of intermodal trains. Outside of the development of STRI's and general improvements in terminals and ports, the key programmes are listed below.
2000 (onwards) - Felixstowe branch line - a programme of engineering works to improve pathing availability on what was largely a single-track branch line in the early days of privatisation. The 2019 engineering works saw a new passing loop installed to a length of . The electrification of the line between Felixstowe and is designated as a "priority route(s) to support electrification of railfreight services."
2004 - Ipswich tunnel enhancement - work to lower the floor of the tunnel, thus allowing containers to be carried through the tunnel. This was part of a wider £30 million Strategic Rail Authority programme to enhance the gauge between Felixstowe and Birmingham via London.
2010–2011 - Gauge enhancement on the route between Southampton and the West Midlands.
2012 - Nuneaton North Chord - previous to the chord being built at , freight trains had to cross the tracks on the flat at Nuneaton station. The new chord allows northbound trains to access the down line without conflicting movements of other trains on the busy West Coast Main Line.
2014 - Ipswich Chord - a new chord going from east to north allowing trains to access the Peterborough line from the Port of Felixstowe (and vice versa) without having to reverse in Ipswich yard.
2021 Werrington Dive Under - works undertaken at Werrington Junction north of to allow freight trains to access/egress the Lincoln line and the March line without conflicting with fast passenger trains on the East Coast Main Line.
2030 (possible) - a gauge enhancement of the Northallerton–Eaglescliffe line to bring that line, the Stillington line and beyond to to W12 gauge clearance.
Network Rail have other schemes in the proposal category that can affect intermodal traffic. One of these is known as the Castlefield corridor, a section of track between Castlefield Junction in West Manchester, and Manchester Picadilly railway station. Both Trafford Park intermodal terminals have east facing connections that lead onto the Castlefield Corridor, and so must traverse the bottleneck through and . After the Ordsall Chord opened in West Manchester, more trains were diverted to go through this bottleneck causing delays and cancellations, with Network Rail going so far as to label the stretch of line as "congested infrastructure".
Some suggestions have been to have a west facing connection to the intermodal terminals so that they can access the West Coast Main Line via a new curve in the Warrington area. Another proposal, put forward by Railfuture, is to relocate the Manchester intermodal terminals on the old Carrington Branch, and therefore freeing up paths through Castlefield for passenger trains, or to add flex to the operational capacity of the corridor.
Open terminals
Mothballed/unused terminals
The following are either not in use as intermodal terminals at present, but remain connected to the national network. Most will still be in use for rail business, but not handling containers.
Closed terminals
This section relates to former terminals which had dedicated services, and infrastructure such as gantry cranes, which have now closed. It does not include such terminals such as those at ports which operated a service previously. For example, in the early part of the 2000s, containers of car parts were transferred from Avonmouth to Tyne Dock for Nissan. Both these freight terminals still operate, but not necessarily in an intermodal capacity.
Future and proposed sites
There are proposals to also open SRFIs (Strategic Rail Freight Interchanges) at Skypark in Devon, Parkside in Lancashire, Etwall in Derbyshire, Burbage, Peterborough and SIFE (Slough International Freight Exchange) with a connection on the Colnbrook branch.
Operators
Intermodal trains were operated by British Rail from its inception until Privatisation in 1996. Immediately after Privatisation, the main company providing intermodal services was Freightliner, though EWS carried containers on their Enterprise wagonload service, and had started an initial service between Harwich and Doncaster to rival services run by Freightliner from Felixstowe. Later, other operators took on their own services, oftentimes running to their own unique locations, though with the gradual increase in Strategic Railfreight Interchanges (SFRI), many operators would rail containers to the same destinations from the same point of origin.
DIRFT, which opened in 1997, had ten departures daily operated by Freightliner, DB Cargo (previously EWS), and Direct Rail Services. Five of those trains went to Scotland going to their own loading points for each company; typically Coatbridge for Freightliner, Mossend for DB Cargo and either Mossend, Elderslie or Grangemouth for DRS.
Advenza Freight; 2004–2009
British Rail 1967–1997
Direct Rail Services 2001–present
DB Cargo 1996–present
Fastline Freight 2006–2010
Freightliner 1995–present
GB Railfreight 2002–present
See also
Rail freight in Great Britain
Notes
References
Sources
External links
British Rail freight services
Freight transport | Intermodal railfreight in Great Britain | [
"Physics"
] | 3,648 | [
"Physical systems",
"Transport",
"Intermodal transport"
] |
62,854,237 | https://en.wikipedia.org/wiki/Symmetry%20energy | In nuclear physics, the symmetry energy reflects the variation of the binding energy of the nucleons in the nuclear matter depending on its neutron to proton ratio as a function of baryon density. Symmetry energy is an important parameter in the equation of state describing the nuclear structure of heavy nuclei and neutron stars.
References
Nuclear physics | Symmetry energy | [
"Physics"
] | 65 | [
"Nuclear and atomic physics stubs",
"Nuclear physics"
] |
62,855,000 | https://en.wikipedia.org/wiki/Monument%20to%20Jos%C3%A9%20de%20Anchieta | The Monument to José de Anchieta in La Laguna, Tenerife, is a monumental statue of Joseph of Anchieta by Bruno Giorgi. Inaugurated in 1960, it is 5 metres tall, and is located in the square that bears its name, next to the Padre Anchieta roundabout at the entrance to the city.
Description
The monumental sculpture is dedicated to Joseph of Anchieta, who was born in La Laguna in 1534, before going to Brazil as a missionary in 1553. The bronze sculpture is approximately tall, and is on a concrete pedestal. The statue's position is described as "walking towards the sea and looking at La Laguna". It is one of La Laguna's emblematic symbols.
History
The creation of the monument was promoted by a pro-monument commission of the Ayuntamiento of La Laguna, at the prompting of Celso Ferreira da Cunha in the late 1950s.
The monument was created by Bruno Giorgi, and was funded by the Federal government of Brazil. Constructed in Brazil, it was moved to Tenerife in 1960 on the ocean liner Cabo de San Vicente. It was inaugurated on 27 November 1960 at the Brazil roundabout in La Laguna, popularly known as Padre Anchieta roundabout, above the Autopista TF-5. The location was chosen by the artist, and was a wide oval of grass at the time. A decade later, the TF-5 was widened due to increased traffic, and the monument was relocated.
In the 2000s, the roundabout was again reformed, with the creation of a tunnel for the TF-5 and the construction of a new roundabout on top of the tunnel. and the statue was temporarily relocated to the campus of the University of La Laguna. It was moved back to the original location on Saturday 14 July 2007, with the relocation taking around 1.5 hours. In 2013, complaints were made about the statue being hidden by flora, which was later trimmed back, and that it was not illuminated at night.
In 2014, concerns were raised by Tomás Oropesa Hernández that vehicle fumes may be corroding the statue. , it is possible that the monument will move again to permit additional works at the roundabout, which will change the road layout and create an elevated pedestrian walkway, to a new square to be created in the parking lot of the Faculty of Biology.
A small tactile model of the monument was made in 2020.
It was moved to the gardens of the University of La Laguna on 30 March 2022 due to the works taking place at the TF5 roundabout.
In April 2024 the sculpture was installed in the aforementioned new square next to the parking lot of the Faculty of Biology.
References
Buildings and structures in Tenerife
Monuments and memorials in the Canary Islands
1960 sculptures
San Cristóbal de La Laguna
Outdoor sculptures in the Canary Islands
Sculptures in Spain
Colossal statues | Monument to José de Anchieta | [
"Physics",
"Mathematics"
] | 588 | [
"Quantity",
"Colossal statues",
"Physical quantities",
"Size"
] |
62,855,072 | https://en.wikipedia.org/wiki/Log%20%28unit%29 | A log (Hebrew לוג or וג, Romanized lōḡ) is a biblical and halakhic unit of liquid volume.
The word log occurs in the Bible, in Lev. 14:10, 15, 21 which prescribes the korban (asham, "guilt-offering") of a poor metzorah:
And if he be poor, and his means suffice not, then he shall take one he-lamb for a guilt-offering to be waved, to make atonement for him, and one tenth part of an ephah of fine flour mingled with oil for a meal-offering, and a log of oil;
Unit definition, conversion, mnemonics and supports
The Talmud, citing the gematria of an extra scriptural word ZeH "this," which equals twelve (seven plus five), explains that one hin is twelve log:
:
The Gemara elaborates: Now, one hin is twelve log, as it is written: “And of olive oil a hin” (Exodus 30:24), and it is written afterward in the same verse: “Sacred anointing oil, this [zeh] shall be for Me, throughout your generations.” The numerical value [gematria] of zeh is twelve.
The Mishnah immediately preceding, which this Gemara comes to explain, states that a half-hin is six log. Thus a hin is twelve log.
A list of conversions follows:
1 hin (הִין hîn) = 12 logs
1 log = 6 Beitzah (egg)
The log is believed to have been equal to a little over ; thus, a hin was a little over .
See also
Biblical and Talmudic units of measurement
References
Units of volume
Obsolete units of measurement | Log (unit) | [
"Mathematics"
] | 371 | [
"Units of volume",
"Obsolete units of measurement",
"Quantity",
"Units of measurement"
] |
62,856,263 | https://en.wikipedia.org/wiki/Finite%20algebra | In abstract algebra, an associative algebra over a ring is called finite if it is finitely generated as an -module. An -algebra can be thought as a homomorphism of rings , in this case is called a finite morphism if is a finite -algebra.
Being a finite algebra is a stronger condition than being an algebra of finite type.
Finite morphisms in algebraic geometry
This concept is closely related to that of finite morphism in algebraic geometry; in the simplest case of affine varieties, given two affine varieties , and a dominant regular map , the induced homomorphism of -algebras defined by turns into a -algebra:
is a finite morphism of affine varieties if is a finite morphism of -algebras.
The generalisation to schemes can be found in the article on finite morphisms.
References
See also
Finite morphism
Finitely generated algebra
Finitely generated module
Commutative algebra
Algebraic geometry
Algebras | Finite algebra | [
"Mathematics"
] | 197 | [
"Mathematical structures",
"Algebras",
"Fields of abstract algebra",
"Algebraic structures",
"Algebraic geometry",
"Commutative algebra"
] |
62,856,495 | https://en.wikipedia.org/wiki/Vichy%20Catal%C3%A1n | Vichy Catalán is a Spanish brand of carbonated mineral water bottled from its homonymous thermal spring in Caldes de Malavella, Girona. It is the leading carbonated mineral water in Spain, with 40% market share. The brand is owned by Grup Vichy Catalan («Premium Mix Group S.L.») ) by the physician and surgeon Modest Furest i Roca after buying the lands of the water spring in Caldes de Malavella, and discovering the mineral-medicinal properties of its thermal waters. In 2022, the global revenue of the beverage subsidiary amounted to 133.5 million euros, with a profit of 1.58 million euros and a workforce of 410 people.
Composition
Bibliography
Content in this edit is translated from the existing Catalan Wikipedia article at Grup Vichy Catalan; see its history for attribution.
References
External links
Official site
La Tienda Vichy
Manantial de Sant Hilari
Mineral water
Spanish brands | Vichy Catalán | [
"Chemistry"
] | 192 | [
"Mineral water"
] |
62,856,519 | https://en.wikipedia.org/wiki/List%20of%20biomedical%20science%20awards | This list of biomedical science awards is an index to notable awards for biomedical sciences, a set of sciences applying portions of natural science or formal science, or both, to knowledge, interventions, or technology that are of use in health care or public health.
Awards
See also
Lists of awards
Lists of science and technology awards
List of biology awards
List of medicine awards
References
biomedicine | List of biomedical science awards | [
"Technology"
] | 77 | [
"Science and technology awards",
"Lists of science and technology awards"
] |
62,856,556 | https://en.wikipedia.org/wiki/Avibase | Avibase is an online taxonomic database that organizes bird taxonomic and distribution data globally. The database relies on the notion of taxonomic concepts rather than taxonomic names. Avibase incorporates and organizes taxonomic data from the main avian taxonomic publishers (The Clements Checklist of Birds of the World, Handbook of the Birds of the World, BirdLife International, IOC Checklist and the Howard and Moore Complete Checklist of the Birds of the World) and other regional sources (e.g. all editions of the American Ornithological Society Checklist of North American Birds since 1886). Taxonomic concepts in over 230 different taxonomic sources have been mapped and cross-referenced to Avibase concepts.
The website also offers checklists for more than 20,000 geographic regions of the world, species pages with taxonomic information and synonyms, and tools for observers to maintain their own sightings and obtain reports, such as a map showing countries or eBird hotspots with target species.
History and purpose
Avibase was created and is maintained by Denis Lepage, currently senior director, data science and technology at Birds Canada. The data contained in Avibase has been gathered starting around 1991. The Avibase website was launched in June 2003 and has been hosted by Birds Canada (formerly Bird Studies Canada) since its inception.
Features
Taxonomic concepts. The database is organized primarily around a table of unique taxonomic concepts. A taxonomic concept is a way of grouping similar taxa together in a database in a more flexible way as compared to specific species names. Each concept represents a unique biological circumscription and has been assigned a unique alphanumeric ID called Avibase ID. Avibase IDs allow the tracking of congruent taxonomic concepts among publication sources. There are approximately 58,000 unique taxonomic concepts described in Avibase. These include concepts traditionally recognized as species and subspecies, but also other taxonomic groupings (subspecies groups), various alternative taxonomic treatments recognized historically, and other concepts representing hybrids, color morphs and invalid or dubious forms.
Nomenclature data. Each scientific name is described to include citation data and the name associated with the original description. Approximately 87,000 scientific names have been recorded in Avibase, and various types of synonyms are also available.
Regional species checklists are available for more than 20,000 regions of the world. This includes all countries, territories and dependencies, and most regions defined in the GADM subnational layers such as provinces, states, prefectures, counties, departments, municipalities and districts (GADM levels 1 and 2), as well as over 2,500 islands. Regional checklists are available in several taxonomic formats and can incorporate common names in a variety of languages. Data for regional checklists originates from multiple of sources, such as the eBird EBD dataset and forums such as the Facebook Global Rare Bird Alert.
Common names and synonyms are available in 271 different languages and regional variants, and there are 21 languages that have a coverage greater than 85% of species with a known common name.
MyAvibase, launched in 2013, provides free tools for users to maintain their life lists and generate reports that are focused on finding target species that the observer has not yet seen, or general regional statistics (e.g. total number of species by country).
Notes
References
External links
Ornithological citizen science
regional bird checklists
Biodiversity databases
Citizen science | Avibase | [
"Biology",
"Environmental_science"
] | 687 | [
"Biodiversity databases",
"Environmental science databases",
"Biodiversity"
] |
68,569,449 | https://en.wikipedia.org/wiki/Westerlund%201-243 | Westerlund 1-243 or Wd 1-243 is a luminous blue variable (LBV) star undergoing an eruptive phase located within the outskirts of the super star cluster Westerlund 1. Located about from Earth, it has a luminosity of 0.73 million making it one of the most luminous stars known.
Observation
Westerlund 1-243 is the second brightest star in Westerlund 1, behind only Westerlund 1-4.
It is one of several different hypergiant stars in Westerlund 1. It may also have a companion star, possibly an O-type supergiant.
Spectrum
Westerlund 1-243 displays a complex, time-varying spectrum with emission lines of hydrogen, helium and Lyman-α pumped metals, forbidden lines of nitrogen and iron, and a large number of absorption lines from neutral and singly-ionized metals. Many lines are complex emission/absorption blends, with significant spectral evolution occurring on timescales of just a few days.
Properties
Westerlund 1-243 has a temperature of ~8,500 K determined from modelling the absorption line spectrum. It has expanded to a radius of , and a Rosseland radius of . It is radiating at a luminosity of . It is losing mass at a rate of /yr.
Evolution
Westerlund 1-243 is believed to be either in an advanced pre-red supergiant LBV phase, or has evolved through the RSG phase and returned to the blue side of the HR diagram. In the future it is expected to evolve toward a WR phase. The K-band spectrum also implies a higher temperature than that of a typical yellow hypergiant and suggests that Westerlund 1-243 may be evolving back towards a hotter state.
References
Ara (constellation)
Luminous blue variables
A-type hypergiants | Westerlund 1-243 | [
"Astronomy"
] | 377 | [
"Constellations",
"Ara (constellation)"
] |
68,570,848 | https://en.wikipedia.org/wiki/Dioicy | Dioicy () is a sexual system in non-vascular plants where archegonia (female organs) and antheridia (male organs) are produced on separate plants in the gametophyte phase. It is one of the two main sexual systems in bryophytes, the other being monoicy. Both dioicous () and monoicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte.
Description
Dioicy promotes outcrossing. Sexual dimorphism is commonly found in dioicous species. Dioicy is correlated with reduced sporophyte production, due to spatial separation of male and female colonies, scarcity or absence of males.
The term dioecy is inapplicable to bryophytes because it refers to the sexuality of vascular plant sporophytes. Nonetheless dioecy and dioicy are comparable in many respects.
Etymology
The words dioicous and di(o)ecious are derived from οἶκος or οἰκία and δι- (di-), twice, double. ((o)e is the Latin way of transliterating Greek οι, whereas oi is a more straightforward modern way.) Generally, the term and "dioicous" have been restricted to description of haploid sexuality (gametophytic sexuality), and are thus primarily to describe bryophytes in which the gametophyte is the dominant generation. Meanwhile, "dioecious" is used to describe diploid sexuality (sporophytic sexuality), and thus is used to describe tracheophytes (vascular plants) in which the sporophyte is the dominant generation.
Occurrence
Sixty-eight percent of liverwort species, 57% to 60% of moss species, and 40% of hornwort species are dioicous. Dioicy also occurs in algae such as Charales and Coleochaetales.It is also prevalent in brown algae.
In all cases sex determination is genetic.
Evolution of dioicy
The ancestral sexual system in bryophytes is unknown but it has been suggested monoicy and dioicy evolved several times. It has also been suggested that dioicy is a plesiomorphic character for bryophytes. In order for dioicy to evolve from monoicy it needs two mutations, a male sterility mutation and a female sterility mutation.
Hornworts have gone through twice as many transitions from dioicy to monoicy than monoicy to dioicy.
Among moss species the transition from monoicy to dioicy is more common than dioicy to monoicy with there being at least 133 transitions from monoicy to dioicy in moss. Sexual specialization has been used as an explanation for this recurring evolution of dioicy in mosses.
References
Bryophytes
Plant sexuality
Sexual system | Dioicy | [
"Biology"
] | 624 | [
"Behavior",
"Plants",
"Plant sexuality",
"Sex",
"Sexual system",
"Bryophytes",
"Sexuality"
] |
68,571,110 | https://en.wikipedia.org/wiki/Psychoplastogen | Psychoplastogens are a group of small molecule drugs that produce rapid and sustained effects on neuronal structure and function, intended to manifest therapeutic benefit after a single administration. Several existing psychoplastogens have been identified and their therapeutic effects demonstrated; several are presently at various stages of development as medications including ketamine, MDMA, scopolamine, and the serotonergic psychedelics, including LSD, psilocin (the active metabolite of psilocybin), DMT, and 5-MeO-DMT. Compounds of this sort are being explored as therapeutics for a variety of brain disorders including depression, addiction, and PTSD. The ability to rapidly promote neuronal changes via mechanisms of neuroplasticity was recently discovered as the common therapeutic activity and mechanism of action.
Etymology and nomenclature
The term psychoplastogen comes from the Greek roots - (mind), - (molded), and - (producing) and covers a variety of chemotypes and receptor targets. It was coined by David E. Olson in collaboration with Valentina Popescu, both at the University of California, Davis.
The term neuroplastogen is sometimes used as a synonym for psychoplastogen, especially when speaking to the biological substrate rather than the therapeutic.
Chemistry
Psychoplastogens come in a variety of chemotypes and chemical families, but, by definition, are small-molecule drugs. Ketamine has been described as, "the prototypical psychoplastogen".
Pharmacology
Psychoplastogens exert their effects by promoting structural and functional neural plasticity through diverse targets including, but not limited to, 5-HT2A, NMDA, and muscarinic receptors. Some are biased agonists. While each compound may have a different receptor binding profile, signaling appears to converge at the tyrosine kinase B (TrkB) and mammalian target of rapamycin (mTOR) pathways. Convergence at TrkB and mTOR parallels that of traditional antidepressants with known efficacies, but with more rapid onset.
Due to their rapid and sustained effects, psychoplastogens could potentially be dosed intermittently. In addition to the neuroplasticity effects, these compounds can have other epiphenomena including sedation, dissociation, and hallucinations.
Psychedelics show complex effects on neuroplasticity and can both promote and inhibit neuroplasticity depending on the circumstances. Single doses of DMT, 5-MeO-DMT, psilocybin, and DOI have been found to produce robust and long-lasting increases in neuroplasticity in animals. Likewise, repeated doses of LSD for 7days increased neuroplasticity. However, chronic intermittent administration of DMT for several weeks resulted in dendritic spine retraction, suggesting physiological homeostatic compensation in response to overstimulation. In addition, DOI has been found to decrease brain-derived neurotrophic factor (BDNF) levels in the hippocampus. The effects of psychedelics on neuroplasticity appear to be dependent on serotonin 5-HT2A receptor activation, as they are abolished in 5-HT2A receptor knockout mice. Non-hallucinogenic serotonin 5-HT2A receptor agonists, like tabernanthalog and lisuride, have also been found to increase neuroplasticity, and to a magnitude comparable to psychedelics.
In terms of neurogenesis, DOI and LSD showed no impact on hippocampal neurogenesis, while psilocybin and 25I-NBOMe decreased hippocampal neurogenesis. 5-MeO-DMT however has been found to increase hippocampal neurogenesis, and this could be blocked by sigma σ1 receptor antagonists.
Approved medical uses
Several psychoplastogens have either been approved or are in development for the treatment of a variety of brain disorders associated with neuronal atrophy where neuroplasticity can elicit beneficial effects.
Esketamine, sold under the brand name Spravato and produced by Janssen Pharmaceuticals, was approved by the FDA in March 2019 for the treatment of Treatment-Resistant Depression (TRD) and suicidal ideation. As of 2022, it is the only psychoplastogen approved in the US for the treatment of a neuropsychiatric disorder. Esketamine is the S(+) enantiomer of ketamine and functions as an NMDA receptor antagonist.
Clinical development
Other psychoplastogens that are being investigated in the clinic include:
MDMA-assisted psychotherapy is being investigated for treatment of PTSD. A recent placebo controlled Phase 3 trial found that 67% of participants in the MDMA+therapy group no longer met the diagnostic criteria for PTSD whereas 32% of those in the placebo+therapy group no longer met PTSD threshold. MDMA-assisted psychotherapy is also currently in Phase 2 trials for eating disorders, anxiety associated with life-threatening illness, and social anxiety in autistic adults.
Psilocybin, a compound in psilocybin mushrooms that serves as a prodrug for psilocin, is currently being investigated in clinical trials of Hallucinogen-Assisted Therapy for a variety of neuropsychiatric disorders. To date studies have explored the utility of psilocybin in a variety of diseases, including TRD, smoking addiction, and anxiety and depression in people with cancer diagnoses.
LSD is being tested in phase 2 trials for cluster headaches and anxiety.
DMT is being studied for depression.
5-MeO-DMT is being studied for depression and eating disorders.
Ibogaine and Noribogaine are being studied for addiction.
List of known psychoplastogens
Substituted tryptamines: psilocin (including psilocybin and psilacetin), DMT, 5-MeO-DMT
Ergolines: LSD, lisuride
Substituted phenethylamines: DOI, MDMA and mescaline
Dissociatives: ketamine (including esketamine, arketamine),
Iboga-derivatives: ibogaine, noribogaine, tabernanthine and tabernanthalog
AAZ-A-154
Scopolamine
Rapastinel
Tropoflavin (7,8-DHF) (including R7, R13)
LY-341495
Isoflurane
See also
Ariadne (drug)
Neuroplasticity
Notes
References
Neuropharmacology | Psychoplastogen | [
"Chemistry"
] | 1,402 | [
"Pharmacology",
"Neuropharmacology"
] |
68,571,139 | https://en.wikipedia.org/wiki/Point-pair%20separation | In a cyclic order, such as the real projective line, two pairs of points separate each other when they occur alternately in the order. Thus the ordering a b c d of four points has (a,c) and (b,d) as separating pairs. This point-pair separation is an invariant of projectivities of the line.
The concept was described by G. B. Halsted at the outset of his Synthetic Projective Geometry:
Given any pair of points on a projective line, they separate a third point from its harmonic conjugate.
A pair of lines in a pencil separates another pair when a transversal crosses the pairs in separated points.
See also
Separation relation
References
G. B. Halsted (1906) Synthetic Projective Geometry, Introduction, p. 7 via Internet Archive
Edward V. Huntington and Kurt E. Rosinger (1932) "Postulates for Separation of Point-Pairs (Reversible order on a closed line)", Proceedings of the American Academy of Arts and Sciences 67(4): 61–145,
Bertrand Russell (1903) The Principles of Mathematics, Separation of couples via Internet Archive
Projective geometry | Point-pair separation | [
"Mathematics"
] | 232 | [
"Order theory"
] |
68,572,267 | https://en.wikipedia.org/wiki/Method%20of%20moments%20%28electromagnetics%29 | The method of moments (MoM), also known as the moment method and method of weighted residuals, is a numerical method in computational electromagnetics. It is used in computer programs that simulate the interaction of electromagnetic fields such as radio waves with matter, for example antenna simulation programs like NEC that calculate the radiation pattern of an antenna. Generally being a frequency-domain method, it involves the projection of an integral equation into a system of linear equations by the application of appropriate boundary conditions. This is done by using discrete meshes as in finite difference and finite element methods, often for the surface. The solutions are represented with the linear combination of pre-defined basis functions; generally, the coefficients of these basis functions are the sought unknowns. Green's functions and Galerkin method play a central role in the method of moments.
For many applications, the method of moments is identical to the boundary element method. It is one of the most common methods in microwave and antenna engineering.
History
Development of boundary element method and other similar methods for different engineering applications is associated with the advent of digital computing in the 1960s. Prior to this, variational methods were applied to engineering problems at microwave frequencies by the time of World War II. While Julian Schwinger and Nathan Marcuvitz have respectively compiled these works into lecture notes and textbooks, Victor Rumsey has formulated these methods into the "reaction concept" in 1954. The concept was later shown to be equivalent to the Galerkin method. In the late 1950s, an early version of the method of moments was introduced by Yuen Lo at a course on mathematical methods in electromagnetic theory at University of Illinois.
In the 1960s, early research work on the method was published by Kenneth Mei, Jean van Bladel and Jack Richmond. In the same decade, the systematic theory for the method of moments in electromagnetics was largely formalized by Roger Harrington. While the term "the method of moments" was coined earlier by Leonid Kantorovich and Gleb Akilov for analogous numerical applications, Harrington has adapted the term for the electromagnetic formulation. Harrington published the seminal textbook Field Computation by Moment Methods on the moment method in 1968. The development of the method and its indications in radar and antenna engineering attracted interest; MoM research was subsequently supported United States government. The method was further popularized by the introduction of generalized antenna modeling codes such as Numerical Electromagnetics Code, which was released into public domain by the United States government in the late 1980s. In the 1990s, introduction of fast multipole and multilevel fast multipole methods enabled efficient MoM solutions to problems with millions of unknowns.
Being one of the most common simulation techniques in RF and microwave engineering, the method of moments forms the basis of many commercial design software such as FEKO. Many non-commercial and public domain codes of different sophistications are also available. In addition to its use in electrical engineering, the method of moments has been applied to light scattering and plasmonic problems.
Background
Basic concepts
An inhomogeneous integral equation can be expressed as:
where denotes a linear operator, denotes the known forcing function and denotes the unknown function. can be approximated by a finite number of basis functions ():
By linearity, substitution of this expression into the equation yields:
We can also define a residual for this expression, which denotes the difference between the actual and the approximate solution:
The aim of the method of moments is to minimize this residual, which can be done by using appropriate weighting or testing functions, hence the name method of weighted residuals. After the determination of a suitable inner product for the problem, the expression then becomes:
Thus, the expression can be represented in the matrix form:
The resulting matrix is often referred as the impedance matrix. The coefficients of the basis functions can be obtained through inverting the matrix. For large matrices with a large number of unknowns, iterative methods such as conjugate gradient method can be used for acceleration. The actual field distributions can be obtained from the coefficients and the associated integrals. The interactions between each basis function in MoM is ensured by Green's function of the system.
Basis and testing functions
Different basis functions can be chosen to model the expected behavior of the unknown function in the domain; these functions can either be subsectional or global. Choice of Dirac delta function as basis function is known as point-matching or collocation. This corresponds to enforcing the boundary conditions on discrete points and is often used to obtain approximate solutions when the inner product operation is cumbersome to perform. Other subsectional basis functions include pulse, piecewise triangular, piecewise sinusoidal and rooftop functions. Triangular patches, introduced by S. Rao, D. Wilton and A. Glisson in 1982, are known as RWG basis functions and are widely used in MoM. Characteristic basis functions were also introduced to accelerate computation and reduce the matrix equation.
The testing and basis functions are often chosen to be the same; this is known as the Galerkin method. Depending on the application and studied structure, the testing and basis functions should be chosen appropriately to ensure convergence and accuracy, as well as to prevent possible high order algebraic singularities.
Integral equations
Depending on the application and sought variables, different integral or integro-differential equations are used in MoM. Radiation and scattering by thin wire structures, such as many types of antennas, can be modeled by specialized equations. For surface problems, common integral equation formulations include electric field integral equation (EFIE), magnetic field integral equation (MFIE) and mixed-potential integral equation (MPIE).
Thin-wire equations
As many antenna structures can be approximated as wires, thin wire equations are of interest in MoM applications. Two commonly used thin-wire equations are Pocklington and Hallén integro-differential equations. Pocklington's equation precedes the computational techniques, having been introduced in 1897 by Henry Cabourn Pocklington. For a linear wire that is centered on the origin and aligned with the z-axis, the equation can be written as:
where and denote the total length and thickness, respectively. is the Green's function for free space. The equation can be generalized to different excitation schemes, including magnetic frills.
Hallén integral equation, published by E. Hallén in 1938, can be given as:
This equation, despite being more well-behaved than the Pocklington's equation, is generally restricted to the delta-gap voltage excitations at the antenna feed point, which can be represented as an impressed electric field.
Electric field integral equation (EFIE)
The general form of electric field integral equation (EFIE) can be written as:
where is the incident or impressed electric field. is the Green function for Helmholtz equation and represents the wave impedance. The boundary conditions are met at a defined PEC surface. EFIE is a Fredholm integral equation of the first kind.
Magnetic field integral equation (MFIE)
Another commonly used integral equation in MoM is the magnetic field integral equation (MFIE), which can be written as:
MFIE is often formulated to be a Fredholm integral equation of the second kind and is generally well-posed. Nevertheless, the formulation necessitates the use of closed surfaces, which limits its applications.
Other formulations
Many different surface and volume integral formulations for MoM exist. In many cases, EFIEs are converted to mixed potential integral equations (MFIE) through the use of Lorenz gauge condition; this aims to reduce the orders of singularities through the use of magnetic vector and scalar electric potentials. In order to bypass the internal resonance problem in dielectric scattering calculations, combined-field integral equation (CFIE) and Poggio—Miller—Chang—Harrington—Wu—Tsai (PMCHWT) formulations are also used. Another approach, the volumetric integral equation, necessitates the discretization of the volume elements and is often computationally expensive.
MoM can also be integrated with physical optics theory and finite element method.
Green's functions
Appropriate Green's function for the studied structure must be known to formulate MoM matrices: automatic incorporation of the radiation condition into the Green's function makes MoM particularly useful for radiation and scattering problems. Even though the Green function can be derived in closed form for very simple cases, more complex structures necessitate numerical derivation of these functions.
Full wave analysis of planarly-stratified structures in particular, such as microstrips or patch antennas, necessitate the derivation of Green's functions that are peculiar to these geometries. This can be achieved in two different methods. In the first method, known as spectral-domain approach, the inner products and convolution operation for MoM matrix entries are evaluated in the Fourier space with analytically-derived spectral-domain Green's functions through Parseval's theorem. The other approach is based on the use of spatial-domain Green's functions. This involves the inverse Hankel transform of the spectral-domain Green's function, which is defined on the Sommerfeld integration path. Nevertheless, this integral cannot be evaluated analytically, and its numerical evaluation is often computationally expensive due to the oscillatory kernels and slowly-converging nature of the integral. Common approaches for evaluating these integrals include tail extrapolation approaches such as weighted-averages method.
Other approaches include the approximation of the integral kernel. Following the extraction of quasi-static and surface pole components, these integrals can be approximated as closed-form complex exponentials through Prony's method or generalized pencil-of-function method; thus, the spatial Green's functions can be derived through the use of appropriate identities such as Sommerfeld identity. This method is known in the computational electromagnetics literature as the discrete complex image method (DCIM), since the Green's function is effectively approximated with a discrete number of image dipoles that are located within a complex distance from the origin. The associated Green's functions are referred as closed-form Green's functions. The method has also been extended for cylindrically-layered structures.
Rational-function fitting method, as well as its combinations with DCIM, can also be used to approximate closed-form Green's functions. Alternatively, the closed-form Green's function can be evaluated through method of steepest descent. For the periodic structures such as phased arrays and frequency selective surfaces, series acceleration methods such as Kummer's transformation and Ewald summation is often used to accelerate the computation of the periodic Green's function.
See also
Boundary element method
Characteristic mode analysis
Discrete dipole approximation
Fast multipole method
Finite element method
Multilevel fast multipole method
Notes
References
Bibliography
Computational electromagnetics
Numerical differential equations | Method of moments (electromagnetics) | [
"Physics"
] | 2,209 | [
"Computational electromagnetics",
"Computational physics"
] |
68,572,415 | https://en.wikipedia.org/wiki/Daniel%20O%27Leary%20%28chemist%29 | Daniel J. O'Leary is an American organic chemist. He is the Carnegie Professor of Chemistry at Pomona College in Claremont, California, and runs a lab that uses nuclear magnetic resonance spectroscopy to study compounds.
References
External links
Faculty page at Pomona College
Year of birth missing (living people)
Living people
Pomona College faculty
American organic chemists
Linfield University alumni
University of California, Los Angeles alumni | Daniel O'Leary (chemist) | [
"Chemistry"
] | 82 | [
"Organic chemists",
"American organic chemists"
] |
68,572,474 | https://en.wikipedia.org/wiki/Cynthia%20Selassie | Cynthia Rachel D. Selassie is an American bio-organic and medicinal chemist known for her work with quantitative structure-activity relationships (QSAR). She is the Blanche and Frank R. Seaver Professor of Science and professor of chemistry at Pomona College in Claremont, California.
Early life and education
Selassie was a student of Corwin Hansch, who pioneered the concept of QSAR. She studied at Mount St. Mary's College, Duke University, and the University of Southern California, where she received her doctorate.
Career
Selassie began teaching at Pomona College in 1990. She currently holds the Blanche and Frank R. Seaver Professor of Science and Professor of Chemistry endowed chair.
References
External links
Faculty page at Pomona College
Year of birth missing (living people)
Living people
Pomona College faculty
American women chemists
American organic chemists
American pharmacologists
Women pharmacologists
21st-century American women | Cynthia Selassie | [
"Chemistry"
] | 190 | [
"Organic chemists",
"American organic chemists"
] |
68,572,841 | https://en.wikipedia.org/wiki/Planctomycetaceae | Planctomycetaceae is the only family in the order Planctomycetales within the Bacteria. Species within this family are mostly spherical, inhabiting a vast array of aquatic environments with the majority being in marine ecosystems. Planctomycetaceae species are generally aerobic, but are uniquely classified by fatty acid synthesis and stalk-like formations.
Morphology
When compared to other species of the order Planctomycetales, species of the Planctomycetaceae family have very few unique characteristics that can taxonomically distinguish them from other related families. Planctomycetaceae species typically form colonies of a pink or white hue. Their cell structure has been recorded to be spherical, but many species are elliptical or pear-shaped; all species range from 0.4 micrometers to 2.5 micrometers in size.
When reproducing, cell structures of Planctomycetaceae are usually observed to be in either a rosette or aggregate grouping; the species Thalassoglobus neptunius is the only known example in this family capable of growing in chains. Some members of Planctomycetaceae (including other taxonomic groups of Planctomycetota) develop stalk-like projections. The species Planctomyces bekefii is well-known in this family for its stalks, using them to connect newly produced cells.
Physiology
Families in Planctomycetales that have more research conducted have been noted to undergo anaerobic respiration, with the family Brocadiaceae being well known for its anaerobic ammonium redox (anammox) capabilities. Planctomycetaceae is one of the many families of Planctomycetales that is both aerobic and cannot do anammox reactions.
Similar to other families, members of Planctomycetaceae are capable of motility using flagella with some having cycles of motile and immotile lifestyles. Standing out from other bacteria, this group has been able to utilize its stalk-like structures to aid in biofilm production, providing a second source of adherence than usual extracellular polymeric substances.
Fatty acids and lipids synthesized by Planctomycetaceae are similar in composition to other families of the order Planctomycetales, but are unique enough to be considered taxonomically critical. Phosphocholine, phosphatidylcholine, and phosphatidylglycerol are considered the major lipids of this family, which only some other families are capable of synthesizing. Most notably, fatty acid C18:1-ω9C is synthesized only within this family of Planctomycete bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). As of 2022, researchers have discovered that there are currently 14 genera and 29 species within Planctomycetaceae.
Genera incertae sedis:
Planctomyces Gimesi 1924
"Rhodopilula" Frank 2011
"Stratiformator" Kumar et al. 2023
"Thermopirellula" Liu et al. 2012
References
Planctomycetota
Bacteria families | Planctomycetaceae | [
"Biology"
] | 681 | [
"Bacteria stubs",
"Bacteria"
] |
68,572,920 | https://en.wikipedia.org/wiki/Gemmataceae | Gemmataceae is a family of bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
References
Planctomycetota
Bacteria families | Gemmataceae | [
"Biology"
] | 58 | [
"Bacteria stubs",
"Bacteria"
] |
68,572,963 | https://en.wikipedia.org/wiki/Isosphaeraceae | Isosphaeraceae is a family of bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
References
Planctomycetota
Bacteria families | Isosphaeraceae | [
"Biology"
] | 60 | [
"Bacteria stubs",
"Bacteria"
] |
68,572,993 | https://en.wikipedia.org/wiki/Pirellulales | Pirellulales is an order of bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
See also
List of bacterial orders
List of bacteria genera
References
Planctomycetota
Bacteria orders
Taxa described in 2020 | Pirellulales | [
"Biology"
] | 73 | [
"Bacteria stubs",
"Bacteria"
] |
68,573,019 | https://en.wikipedia.org/wiki/Lacipirellulaceae | Lacipirellulaceae is a family of bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
See also
List of bacterial orders
List of bacteria genera
References
Planctomycetota
Bacteria families
Taxa described in 2020 | Lacipirellulaceae | [
"Biology"
] | 75 | [
"Bacteria stubs",
"Bacteria"
] |
68,573,057 | https://en.wikipedia.org/wiki/Thermoguttaceae | Thermoguttaceae is a family of bacteria.
See also
List of bacterial orders
List of bacteria genera
References
Planctomycetota | Thermoguttaceae | [
"Biology"
] | 31 | [
"Bacteria stubs",
"Bacteria"
] |
68,573,081 | https://en.wikipedia.org/wiki/Pirellulaceae | The Pirellulaceae are a family of bacteria.
Phylogeny
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
See also
List of bacterial orders
List of bacteria genera
References
Planctomycetota
Bacteria families | Pirellulaceae | [
"Biology"
] | 70 | [
"Bacteria stubs",
"Bacteria"
] |
68,573,862 | https://en.wikipedia.org/wiki/Br%C3%ADd%20Ryan | Bríd M. Ryan is an Irish biomedical scientist and cancer researcher. She was an investigator at the National Cancer Institute from 2013 to 2021.
Early life and education
Ryan grew up on a farm and dairy in Ireland. She has five sisters. Ryan always enjoyed science and decided she wanted to be a cancer researcher as a teenager. She completed her undergraduate training in biochemistry at University College Cork in 2001.
Ryan received her Ph.D. in Cancer Biology from St. Vincent’s University Hospital and UCD School of Medicine and in 2005 was accepted into the National Cancer Institute (NCI) Cancer Prevention Fellowship Program. In 2007, she completed a Masters of Public Health at School of Public Health and Population Sciences, University College Dublin. Ryan worked under the mentorship of Curtis C. Harris during her postdoctoral training at the NCI.
As a postdoc at NCI, she was involved in research that bridged both basic science and translational molecular epidemiology. Initially, Ryan studied populations of European descent, but it became clear that, within the United States, significant disparities in incidence and survival existed across populations.
Career
In 2013, Ryan became a National Institutes of Health (NIH) Stadtman Investigator in the Laboratory of Human Carcinogenesis at the NCI Center for Cancer Research (CCR). Her work focused on health disparities related to lung cancer across different populations.
Ryan left NIH in April 2021 and joined MiNA Therapeutics, where she is VP, Oncology and Immunology Research.
Ryan was among the first to demonstrate asymmetric division of DNA in cancer. This process is thought to underpin how tumors self-renew and regenerate. Since then, her studies have examined the roles of the tumor microenvironment and p53 in regulating this process in lung cancer. Her lab oversees an integrative and translational approach to lung cancer research, examining the genetic, environmental, and biological contributions to racial disparities in lung cancer incidence. Her research program also developed biomarkers for the early detection of lung cancer.
Works
References
External links
Living people
Year of birth missing (living people)
Place of birth missing (living people)
21st-century Irish women scientists
Irish medical researchers
Women medical researchers
Cancer researchers
National Institutes of Health people
Irish emigrants to the United States
Alumni of University College Cork
Alumni of University College Dublin
Irish biochemists
Irish women chemists
Women biochemists
21st-century biochemists
21st-century Irish chemists
Irish women in health professions | Bríd Ryan | [
"Chemistry"
] | 509 | [
"Biochemists",
"Women biochemists"
] |
68,577,665 | https://en.wikipedia.org/wiki/Lak%20wettability%20index | In petroleum engineering, Lak wettability index is a quantitative indicator to measure wettability of rocks from relative permeability data. This index is based on a combination of Craig's first rule. and modified Craig's second rule
where
: Lak wettability index (index values near -1 and 1 represent strongly oil-wet and strongly water-wet rocks, respectively)
: Water relative permeability measured at residual oil saturation
: Water saturation at the intersection point of water and oil relative permeability curves (fraction)
: Residual oil saturation (in fraction)
: Irreducible water saturation (in fraction)
: Reference crossover saturation (in fraction) defined as:
and and are two constant coefficients defined as:
and if
and if
and if
To use the above formula, relative permeability is defined as the effective permeability divided by the oil permeability measured at irreducible water saturation.
Craig's triple rules of thumb
Craig proposed three rules of thumb for interpretation of wettability from relative permeability curves. These rules are based on the value of interstitial water saturation, the water saturation at the crossover point of relative permeability curves (i.e., where relative permeabilities are equal to each other), and the normalized water permeability at residual oil saturation (i.e., normalized by the oil permeability at interstitial water saturation).
According to Craig's first rule of thumb, in water-wet rocks the relative permeability to water at residual oil saturation is generally less than 30%, whereas in oil-wet systems this is greater than 50% and approaching 100%. The second rule of thumb considers a system as water-wet, if saturation at the crossover point of relative permeability curves is greater than water saturation of 50%, otherwise oil-wet. The third rule of thumb states that in a water-wet rock the value of interstitial water saturation is usually greater than 20 to 25% pore volume, whereas this is generally less than 15% pore volume (frequently less than 10%) for an oil-wet porous medium.
Modified Craig's second rule
In 2021, Abouzar Mirzaei-Paiaman investigated the validity of Craig's rules of thumb and showed that while the third rule is generally unreliable, the first rule is suitable. Moreover, he showed that the second rule needed a modification. He pointed out that using 50% water saturation as a reference value in the Craig's second rule is unrealistic. That author defined a reference crossover saturation (RCS). According to the modified Craig's second rule, the crossover point of relative permeability curves lies to the right of RCS in water-wet rocks, whereas for oil-wet systems, the crossover point is expected to be located at the left of the RCS.
Modified Lak wettability index
Modified Lak wettability index exists which is based on the areas below water and oil relative permeability curves.
where
: modified Lak wettability index (index values near -1 and 1 represent strongly oil-wet and strongly water-wet rocks, respectively)
: Area under the oil relative permeability curve
: Area under the water relative permeability curve
See also
Wetting
Amott test
Relative permeability
TEM-function
USBM wettability index
References
Petroleum geology
Surface science
Fluid mechanics | Lak wettability index | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 719 | [
"Surface science",
"Petroleum",
"Civil engineering",
"Condensed matter physics",
"Petroleum geology",
"Fluid mechanics"
] |
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