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54,248,584 | https://en.wikipedia.org/wiki/Optimal%20instruments | In statistics and econometrics, optimal instruments are a technique for improving the efficiency of estimators in conditional moment models, a class of semiparametric models that generate conditional expectation functions. To estimate parameters of a conditional moment model, the statistician can derive an expectation function (defining "moment conditions") and use the generalized method of moments (GMM). However, there are infinitely many moment conditions that can be generated from a single model; optimal instruments provide the most efficient moment conditions.
As an example, consider the nonlinear regression model
where is a scalar (one-dimensional) random variable, is a random vector with dimension , and is a -dimensional parameter. The conditional moment restriction is consistent with infinitely many moment conditions. For example:
More generally, for any vector-valued function of , it will be the case that
.
That is, defines a finite set of orthogonality conditions.
A natural question to ask, then, is whether an asymptotically efficient set of conditions is available, in the sense that no other set of conditions achieves lower asymptotic variance. Both econometricians and statisticians have extensively studied this subject.
The answer to this question is generally that this finite set exists and have been proven for a wide range of estimators. Takeshi Amemiya was one of the first to work on this problem and show the optimal number of instruments for nonlinear simultaneous equation models with homoskedastic and serially uncorrelated errors. The form of the optimal instruments was characterized by Lars Peter Hansen, and results for nonparametric estimation of optimal instruments are provided by Newey. A result for nearest neighbor estimators was provided by Robinson.
In linear regression
The technique of optimal instruments can be used to show that, in a conditional moment linear regression model with iid data, the optimal GMM estimator is generalized least squares. Consider the model
where is a scalar random variable, is a -dimensional random vector, and is a -dimensional parameter vector. As above, the moment conditions are
where is an instrument set of dimension (). The task is to choose to minimize the asymptotic variance of the resulting GMM estimator. If the data are iid, the asymptotic variance of the GMM estimator is
where .
The optimal instruments are given by
which produces the asymptotic variance matrix
These are the optimal instruments because for any other , the matrix
is positive semidefinite.
Given iid data , the GMM estimator corresponding to is
which is the generalized least squares estimator. (It is unfeasible because is unknown.)
References
Further reading
Econometric modeling
Moment (mathematics) | Optimal instruments | [
"Physics",
"Mathematics"
] | 557 | [
"Mathematical analysis",
"Moments (mathematics)",
"Physical quantities",
"Moment (physics)"
] |
54,248,805 | https://en.wikipedia.org/wiki/Stock%20sampling | Stock sampling is sampling people in a certain state at the time of the survey. This is in contrast to flow sampling, where the relationship of interest deals with duration or survival analysis. In stock sampling, rather than focusing on transitions within a certain time interval, we only have observations at a certain point in time. This can lead to both left and right censoring. Imposing the same model on data that have been generated under the two different sampling regimes can lead to research reaching fundamentally different conclusions if the joint distribution across the flow and stock samples differ sufficiently.
Stock sampling essentially leads to a sample selection problem. This selection issue is akin to the truncated regression model where we face selection on the basis of a binary response variable, but the problem has been referred to as length-biased sampling in this specific context. Consider, for example, the figure below that plots some duration data. If a researcher would revert to stock sampling and only sample and survey individuals at the survey dates (i.e. the survey data, 12 months after the survey date, etc.), there is a high likelihood the short duration spells will be omitted from the sample, as some durations shorter than 12 months are necessarily omitted from the sample:
A number of methods to adjust for these sampling issues have been proposed. One can appropriately adjust the maximum likelihood estimation for censored flow data for the sample selection, or use nonparametric estimation methods for censored flow data for the sample selection, or use nonparametric estimation methods for censored data.
References
Sampling (statistics)
Design of experiments
Actuarial science
Single-equation methods (econometrics)
Regression models
Mathematical and quantitative methods (economics)
Medical statistics
Clinical trials
Epidemiology | Stock sampling | [
"Mathematics",
"Environmental_science"
] | 350 | [
"Epidemiology",
"Applied mathematics",
"Actuarial science",
"Environmental social science"
] |
54,248,882 | https://en.wikipedia.org/wiki/NanoCLAMP | In the medical field of immunology, nanoCLAMP (CLostridal Antibody Mimetic Proteins) affinity reagents are recombinant 15 kD antibody mimetic proteins selected for tight, selective and gently reversible binding to target molecules. The nanoCLAMP scaffold is based on an IgG-like, thermostable carbohydrate binding module family 32 (CBM32) from a Clostridium perfringens hyaluronidase (Mu toxin). The shape of nanoCLAMPs approximates a cylinder of approximately 4 nm in length and 2.5 nm in diameter, roughly the same size as a nanobody (). nanoCLAMPs to specific targets are generated by varying the amino acid sequences and sometimes the length of three solvent exposed, adjacent loops that connect the beta strands making up the beta-sandwich fold, conferring binding affinity and specificity for the target.
Properties
nanoCLAMPs are the first antibody mimetics described to be polyol-responsive, meaning they release their targets upon exposure to a non-chaotropic salt and a polyol, such as propylene glycol. This property has been shown to be useful for purifying functional proteins and protein complexes by affinity purification. nanoCLAMPs are easily produced in the cytoplasm of E. coli, with typical yields in the range of 50 to 300 mg/L culture. Because nanoCLAMPs are devoid of cysteines, an engineered C-terminal cysteine can be used for site-directed conjugation of entities like fluorophores or resins using thiol-chemistry.
Development and applications
nanoCLAMPs were developed in the laboratories of Nectagen. nanoCLAMP phage display libraries were constructed that contained variations on 16 surface amino acids in three loops with function diversities of approximately 109 variants. These libraries have been screened for binders to target proteins and peptides, typically yielding between 1 and 30 unique binders to the target.
Purified nanoCLAMPs containing a single C-terminal cysteine can be easily conjugated to halo-acetyl activated agarose resins under native or denaturing conditions, and the resulting thioether bond renders the resins leach-proof. Targets can be purified to apparent homogeneity in a single-step. The polyol-responsive nature of the resins allows the targets to be eluted with 0.75 M ammonium sulfate and 40% propylene glycol at pH 7.9, conditions which have been shown to preserve native structure and protein complexes.
nanoCLAMPs have been produced that target green fluorescent protein (GFP), mCherry, SUMO (SMT3), NusA, avidin, NeutrAvidin, maltose-binding protein (MBP), thioredoxin 1, beta-galactosidase, SlyD, and others. Typical binding capacities of resins range from 1 to 4 mg/ml resin. Because nanoCLAMPs readily refold, nanoCLAMP resins can be regenerated multiple times using guanidinium chloride to clean the resin.
References
External links
Nectagen, Inc., the developer
Antibody mimetics | NanoCLAMP | [
"Chemistry"
] | 674 | [
"Antibody mimetics",
"Molecular biology"
] |
54,249,143 | https://en.wikipedia.org/wiki/Khaled%20A.%20Mahdi | Khaled A. Mahdi (Arabic: خالد مهدي; born 1 January 1970) held the position of the Secretary-General of the General Secretariat of the Supreme Council for Planning and Development (GSSCPD) of Kuwait in 2016 till 2024. He succeeded Mr. Hashem Alrefee (2014 - 2015) and Dr. Adel Alweqayan (2014 - 2007). The GSSCPD steers the long-term Kuwait National Development Plan (KNDP), part of the vision for New Kuwait by His Highness the Emir of Kuwait, Sabah Al-Ahmad Al-Jaber Al-Sabah, which "mobilizes development efforts across seven pillars with the aim of transforming Kuwait into a financial, cultural, and institutional leader in the region by 2035".
Early life and education
Mahdi was born on 1 January 1970. He received his Bachelor's degree in chemical engineering from University of Toronto, Canada, and his Master's in the same field from the Illinois Institute of Technology, USA. Mahdi received his PhD in chemical engineering from Northwestern University, USA, where he specialized on applications of statistical mechanics on complex thermodynamic systems working with Professor Monica Olvera de la Cruz research group.
Career
Mahdi starting his academic career working in the Water Resource Division in the Kuwait Institute for Scientific Researches before moving to Kuwait University to become Associate Professor of Chemical Engineering, where he taught 30 different courses in general engineering, chemical engineering as well as management sciences. He received Kuwait University's Best Teaching Award in 2009 among other honors and awards. Mahdi has authored or co-authored more than 75 journal articles, book chapters, conference papers, patents, and books in different fields. His primary interest is the study of modeling complex systems and process optimization. Mahdi and collaborators also established SYNERGY with Prof. Maytham Safar, Computer Engineering Department at Kuwait University. He is a senior member of the American Institute of Chemical Engineers (AIChE) and several other professional societies.
Supreme Council for Planning and Development
Under Mahdi's directorship, the Secretariat has been keen "on implementing the Sustainable Development Goals (SDGs), or the 2030 Agenda, adopted by the UN in September 2015," and have already "achieved a considerable part of the Sustainable Development Goals" for Post-2015.
A key mission of the KNDP is to create stronger integration between Kuwait's public and private sectors, and in an interview with the Oxford Business Group as part of their Kuwait 2017 report, Mahdi shared that "the government stated very clearly its intentions to transition its role in the economy from an operator to regulator, from wealth distribution to wealth creation, and to entrust the economy to the private sector." Additionally, Mahdi oversees the GSSCPD's engagement in development programming and support of the national development agenda, working with various sectors and segments of the population.
In Mahdi's own words about the implementation of the national plan, the Secretariat looks to build "a solid commercial and financial infrastructure, and this cements us as a financial and commercial hub", through projects like the Knowledge Transfer and Small and Medium Enterprises (SME) expo, The knowledge Economy Forum and the Kuwait Public Policy Center (KPPC).
Government and public sector work
Since 2016, Mahdi as served as the Secretary-General of the Supreme Council for Planning and Development in the Government of Kuwait. Prior to this appointment, he was the Assistant Secretary General for the Follow-up and Future Forecasting besides being the Acting Assistant Secretary General for Planning.
Mahdi sits in several government boards and higher committees, mainly the Public Authority for Industry (PAI), Kuwait Institute for Scientific Research (KISR), Public Authority for Civil Information (PACI), and the Public Authority for Housing and Welfare (PAHW).He is a member of the Supreme Council for Education and is on the Board of Trustees of the National Center for Education Development (NCED). He serves as member in high-level committees such as the Economic and Fiscal Reform Monitoring Committee , the Humanitarian Foreign Aid Committee, Fiscal Budgeting Framework, Kuwait Demographic Disparities Committee, the Development of Kuwait Islands Committee, the Executive Committee of the Silk City, Kuwait Master Plan 2040 Committee, Kuwait Bond Debut Roadshow, and the Kuwait University Mega Projects Committee.
He also serves other government sub-committees and leading government work groups, and has spoken extensively at national and international conferences, such as the Kuwait Housing & Residential Development Forum and Kuwait Infrastructure Week in 2017.
Mahdi chairs the Consultants Selection Committee during the period 2016-2017 and is the National Director of the Country Program Action Plan of the United Nations Development Programme in Kuwait, and currently presides over the National Committee for the Implementation of Agenda 2030.
Mahdi steers chairs the national SDGs 2030 permanent standing committee and leads the vision of the state, “New Kuwait 2035”. He established the Kuwait Public Policy Center (KPPC) and its Nudge Unit; also oversees the research centers including The National Knowledge Economy Center, the National Sustainable Development Observatory and the National Development Research Center. He also led the initiative to produce Kuwait’s first Macro-Economic Model by collaborating with Oxford Economics. He has also hosted the IPIECA’s report “the Mapping the Oil and Gas Industry to the SDGs: An Atlas”, and the World Energy Outlook 2018’s report of the IEO. Mahdi has also developed strategic partnerships with local, regional and international organizations to support knowledge sharing and development.
Awards and honours
In October 2018, Dr. Khaled received the People First Leader GCC HR Award for his government services at the 6th Annual GOV HR Summit. Abu Dhabi, UAE.
References
Illinois Institute of Technology alumni
1970 births
Living people
Northwestern University alumni
Academic staff of Kuwait University
Kuwaiti engineers
Chemical engineers
University of Toronto alumni | Khaled A. Mahdi | [
"Chemistry",
"Engineering"
] | 1,196 | [
"Chemical engineering",
"Chemical engineers"
] |
54,249,535 | https://en.wikipedia.org/wiki/Corps%20Commander | Corps Commander, or "Corps Commander: Operational Manoeuvre Group" is a set of micro-armour Miniature wargaming rules designed by Bruce Rea Taylor and Andy Ashton and published in the UK by Tabletop games copyrighted by B. A. Rea Taylor, A. Ashton & Tabletop Games July 1986.
These rules simulates modern warfare between forces of up to Corps or Army Level in any future war on the Central Front in Europe.
The basic elements (units) in the game are tank and mechanised infantry platoons, infantry companies, and artillery batteries. All aspects of modern warfare are covered including helicopters, air power, NBC, logistics and electronics. A Divisional Level assault can easily be played on a standard 8' x 6' table, whilst a heliborne assault on a vital bridge can be played on a 2' x 2' table. Thus allowing several campaign battles to take place in one evening.
Overview
Bruce Rea Taylor and Andy Ashton originally intended that Corps Commander would be the start of a family of rules, each covering a period and location, as can be seen by the quote from the Rules.
Operational Manoeuvre Group was the first of the Corps Commander / Korps Commander publications. Bruce Rea Taylor died three years after the publication of these rules (1989), at the age of 40. I was unable to find any evidence Andy Ashton made any plans to continue this project.
Bruce Rea Taylor gives a special mention to the Wallasey Wargames Club in the Introduction of the Korps Commander Rules. he used wargaming clubs as a method to play test his rules system.
The primary significance of these rules was it was one of the first game systems which used a scale of 1-2 base(s) per company. The reason why a scale of 1 base per company was not used was to allow for small formations, such as 1-2 SP-AA weapons allocated to a HQ and to ensure the record keeping for the standard company sized formations was not too difficult. However, apart from this, the rules attempted to use a 1 Base = 1 company scale, which allowed players to command one, or more, divisions. Compared with the most common rules used in this period, this was unusual.
In practice the detail and complexity of the rules precluded any possibility of playing a corps level game within a reasonable time frame. Most games would typically field 50 bases, or elements, per side. This represents a force of 25 companies per side. A game of this size which consisted of 12 game-turns, or one game day duration, could be completed within a 4-8 hour period.
History
Bruce Rea Taylor and Andy Ashton published Corps Commander in July 1986. This used the same game system as Korps Commander and can be considered the first of the Corps/Korps Commander system publications. In October 1986 "Digest #3, Engineering Equipment Data, Engineering Lists, Engineering Scenarios" was published, this contained additional material for Corps Commander. In June 1988 "Corps Commander: By Air & Sea" was published, containing yet more supporting material for Corps Commander. The final publication in this family was in August 1988 when "Korps Commander" was published.
While Bruce Rea Taylor published a number of additional books after August 1988, they were all dated after his death on 3 March 1989. No additional Corp/Korps Commander books were published after August 1988. These post August 1988 publications are listed here:
Digest #4, Ultra Modern Army Lists for Challenger II Rules, Apr 1989 (For Challenger II)
Digest #5, Ultra Modern Army Lists for Challenger II Rules, June 1989 (For Challenger II)
There is strong evidence Bruce Rea Taylor built on his earlier rules, Challenger and Firefly, when developing the Corp/Korps Commander Rules. This is especially evident in the equipment specification.
Development
Corps Commander was published in July 1986. Shortly after this an errata sheet was published which was printed on the inside cover of the rules. Digest #3, published in Oct 1986, and contained some additional supporting information, but no changes to the rules. The Air & Sea supplement, printed in June 1988, contained a large number of additional rules, as well as some minor changes to the base rules. The publishing of Korps Commander, in August 1988, contained a large number of changes to the rules. A number of these were as a result of the period, such as the game scale, however a number represents corrections to the original Corps Commander rules.
A number of unusual tactics were available to players of the original Corps Commander rules, which Korps Commander eliminated. In additional to this a number of other changes were implemented which improved the accuracy of the rules. These included;
Rocket artillery could affect more than a single element.
A single forward observer could not bring down an unlimited number of fire support missions in a single game-turn.
The fire effects of a fire combat could affect future fire combats in the same phase, thus an element could, in a limited manner, react to fire before subsequent fire was directed against it.
Elements in concentrated mode could not take advantage of fortification.
MMG indirect fire was added.
Addition of battalion level command, especially for fire support purposes.
Troops mounted in soft transports could no longer conduct close combat more effectively than if dismounted.
The Lorry was added, this was a truck not designed for troops to fight from or around. It represent a large vehicle which was difficult to dismount from and unwise to fight from.
Some additional rules around orders, such as attack, defend, manoeuvre and retreat.
Addition moral modifiers were added to make it harder for element to fight until they were eliminated.
Building fortifications took a lot longer.
Reconnaissance missions could be intercepted by enemy CAP.
Observation missions used standard observation rules to locate targets.
It is likely that these changes were intended to be added to corps commander in a possible future publication, however this never occurred.
Scale
Ground Scale (1/300 scale) : Each centimetre represents 100 metres (1:10000)
Game-Turn Scale : Each daylight Turn represents 1 hour of actual time. Each night Turn represents 2 hour of actual time.
Base/Stand Scale - Each base represents a company, part of a company or a platoon. A Base can have a maximum of 9 Strength points. (If there are more than 9 vehicles or Gun's in a Company, the Company is split into two bases, each of which are similar in strength. This system allows a base to also represent a platoon, such as a support platoon attached to a Headquarters company.)
Vehicle Scale : Each AFV Strength point represents 1 AFV.
Artillery Scale : Each Artillery Strength point represents 1 weapon.
Infantry Scale : Each Infantry Strength Point represents approximately 10 combat troops, or 1 heavy weapon.
Aircraft Scale : Each Aircraft Strength Points represents 1 aircraft.
Base Size (1/300 scale) - A Base which has 1 to 5 strength points has a size of 20mm by 30mm. A Base with more than 5 strength points has a size of 30mm by 30mm.
For comparison purposes the later Korps Commander used a Ground scale of 5 cm = 1 km (1:5000) and a Daylight Game Turn = 1/2 hour. Lightning War - Red Storm uses a base size of 30 cm x 30 cm, a ground scale of 1 cm = 100, (1:10000), a Daylight Game Turn = 2 hours. Panzer Korps, while designed for 15mm/20mm, uses a Ground Scale of 1 cm = 50m (1:5000) for 1/300 scale.
Significance
The primary significance of these rules is the use of a 1 Company = 1-2 Base(s) scale. In 1986/1988 this was unusual. Examples of other similar scaled rules are, Great Battles of WWII Vol. 1 (1995), Panzer Korps (2004). and Lightning War - Red Storm (2001-2008).
1973: Wargame Rules Armour & Infantry 1925 to 1950 v1 Squad / Vehicle
1974: Wargames Rules for Armoured Warfare 1950 to 1985 v1 Squad / Vehicle
1975: Wargame Rules Armour & Infantry 1925 to 1950 v2 Squad / Vehicle
1978: Cambrai to Sinai Squad / Vehicle
1978: Combat Commander 1973-1983 v1 Squad / Vehicle
1979: Combat Commander 1973-1983 v2 Squad / Vehicle
1979: Wargames Rules for Armoured Warfare 1950 to 1985 v2 Squad / Vehicle
1980: Combat Commander 1973-1983 v3 Squad / Vehicle
1983: Challenger Squad / Vehicle
1983: Combined Arms - Rules for WWII inf-Arm Actions Squad / Vehicle
1986: Corps Commander Coy / Platoon *
1987: Firefly Squad / Vehicle
1988: Korps Commander Coy / Platoon *
1988: Combined Arms - Modern Miniature Wargaming Platoon *
The most common scale in the late 80's was 1 Vehicle = 1 Base, later rules used scales of 1 Platoon = 1 Base. The primary issue with the increase of the scale was related to the combat specifications of a base. When a base represents a common vehicle or gun, its speed and combat capabilities are based on the figure itself. When a base represents a mix of vehicles or guns, its speed and combat capabilities may differ from the figure on the base.
Example : A Base which contains 5 x Pz I and 2 x Pz II compared with another base which contains 5 x Pz I and 2 x Pz III. Both would be represented by a Pz I, but would differ in combat capabilities.
Players may be required to keep track of the combat capabilities of individual bases by the use of separate written records, or a value printed on the base. In this case the use of a Board-Game system may be preferable.
Corps/Korps Commander resolved this issue by giving each a Base a value, representing the number of common vehicles or guns. When there were different vehicles or guns in a company, the company would be represented by more than 1 base. Each Base would contain the same vehicle/guns and its value would be the number of vehicle/gun in each base.
See also
Miniature wargaming
References
Miniature wargames
Scale modeling
Playscale miniaturism | Corps Commander | [
"Physics"
] | 2,080 | [
"Scale modeling"
] |
54,250,075 | https://en.wikipedia.org/wiki/Carboalkoxylation | In industrial chemistry, carboalkoxylation is a process for converting alkenes to esters. This reaction is a form of carbonylation. A closely related reaction is hydrocarboxylation, which employs water in place of alcohols.
A commercial application is the carbomethoxylation of ethylene to give methyl propionate:
The process is catalyzed by . Under similar conditions, other Pd-diphosphines catalyze formation of polyethyleneketone.
Methyl propionate ester is a precursor to methyl methacrylate, which is used in plastics and adhesives.
Carboalkoxylation has been incorporated into various telomerization schemes. For example carboalkoxylation has been coupled with the dimerization of 1,3-butadiene. This step produces a doubly unsaturated C9-ester:
Hydroesterification
Related to carboalkoxylation is hydroesterification, the insertion of alkenes and alkynes into the H-O bond of carboxylic acids. Vinyl acetate is produced industrially by the addition of acetic acid to acetylene in the presence of zinc acetate catalysts: Presently, zinc acetate is used as the catalyst:
Further reading
References
Chemical reactions
Carbon monoxide | Carboalkoxylation | [
"Chemistry"
] | 277 | [
"nan"
] |
54,250,570 | https://en.wikipedia.org/wiki/Authepsa | In classical antiquity, an or (, ; from + , "self-boiling", "self-cooking") was a vessel used for water heating. Basically, it was a vase with a central tube used to keep coals.
Dictionary of Greek and Roman Antiquities describes it as follows:
AUTHEPSA (), or “self-boiler”, was a vessel used for heating water or keeping it hot. As is well known, both hot and cold water were served by the attendants at well-appointed Roman tables (, Juv. 5.63, with Mayor's note). For this purpose vessels were used which cannot have differed much in construction from our modern tea-urns (Böttiger, Sabina, 2.30), and like them might be made of costly materials and in artistic designs (, Cic. pro Rose. Amer. 46.133; , Lamprid. Heliog. 19).
Many ingenious contrivances for economical and portable cooking have been found at Pompeii and Herculaneum, and are now in the Museo Nazionale (formerly Borbonico) at Naples. It is probable, however, that the , unlike the and , was not used for cooking; and it is rather to be identified with a utensil from the same collection (Mus. Borbon. vol. iii. pl. 63) in the first cut above. This vessel is in bronze, and of very tasteful workmanship: the cylinder in the centre was filled with charcoal, and has a grating which allowed the air to enter and the ashes to escape. The second cut, from Mus. Borbon. vol. v. pl. 44, shows another of more elaborate construction.
The Russian samovar is likewise explained to mean “self-boiler”, and appears to be little different from the .
References
Heaters
Boilers
Classical antiquity | Authepsa | [
"Chemistry"
] | 396 | [
"Boilers",
"Pressure vessels"
] |
54,250,929 | https://en.wikipedia.org/wiki/Hyperbranched%20aminosilica | Hyperbranched aminosilica is a white powdery substance. The compound, also referred to as HAS can capture and keep CO2 gas due to its branch-like properties that enable amino sites at the tips of the branches to collect the gas. It is made from aziridine and mesoporous silica.
References
Silicon compounds
Amines | Hyperbranched aminosilica | [
"Chemistry"
] | 71 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
54,252,064 | https://en.wikipedia.org/wiki/Resource%20selection%20function | Resource selection functions (RSFs) are a class of functions that are used in spatial ecology to assess which habitat characteristics are important to a specific population or species of animal, by assessing a probability of that animal using a certain resource proportional to the availability of that resource in the environment.
Modeling
Resource Selection Functions require two types of data: location information for the wildlife in question, and data on the resources available across the study area. Resources can include a broad range of environmental and geographical variables, including categorical variables such as land cover type, or continuous variables such as average rainfall over a given time period. A variety of methods are used for modeling RSFs, with logistic regression being commonly used.
RSFs can be fit to data where animal presence is known, but absence is not, such as for species where several individuals within a study area are fitted with a GPS collar, but some individuals may be present without collars.
When this is the case, buffers of various distances are generated around known presence points, with a number of available points generated within each buffer, which represent areas where the animal could have been, but it is unknown whether they actually were. These models can be fit using binomial generalized linear models or binomial generalized linear mixed models, with the resources, or environmental and geographic data, as explanatory variables.
Scale
Resource selection functions can be modeled at a variety of spatial scales, depending on the species and the scientific question being studied. (insert one more sentence on scale)
Most RSFs address one of the following scales, which were defined by Douglas Johnson in 1980 and are still used today:
First order selection: The entire range of a species
Second order selection: The home range of an individual or group of animals
Third order selection: Resource or habitat usage within an individual's or group's home range
Fourth order selection: The procurement of specific resources, such as food, at specific sites
References
Ecology
Mathematical modeling | Resource selection function | [
"Mathematics",
"Biology"
] | 394 | [
"Applied mathematics",
"Mathematical modeling",
"Ecology"
] |
54,252,098 | https://en.wikipedia.org/wiki/High%20flux%20reactor | A High Flux Reactor is a type of nuclear research reactor.
High Flux Isotope Reactor (HFIR), in Oak Ridge, Tennessee, United States of America,
High Flux Australian Reactor (HIFAR), Australia's first nuclear reactor,
High-Flux Advanced Neutron Application Reactor (HANARO), in South Korea.
The High Flux Reactor at Institut Laue–Langevin in France.
High Flux Reactor (HFR) at Petten in the Netherlands
Nuclear research reactors | High flux reactor | [
"Physics"
] | 97 | [
"Nuclear and atomic physics stubs",
"Nuclear physics"
] |
54,253,065 | https://en.wikipedia.org/wiki/NOC%20%28software%29 | NOC is an open-source operations support system for telecommunications service providers. It can maintain network inventory, manage virtual circuits, maintain distributed DNS configuration and manage IP address blocks.
NOC Project is mentioned in the Configuration management and backup tools section of the 2019 GEANT SIG-NOC Tools Survey among other tools used by the community.
See also
Comparison of open-source configuration management software
Infrastructure as code (IaC)
Infrastructure as Code Tools
References
Python (programming language) software
Network management
Software using the BSD license | NOC (software) | [
"Engineering"
] | 107 | [
"Computer networks engineering",
"Network management"
] |
54,253,797 | https://en.wikipedia.org/wiki/Sphinx%20%28home%20automation%20system%29 | The Sphinx () was an experimental Soviet project for a home automation system, commissioned by the State Committee for Science and Technology and designed by Dmitry Azrikan, in collaboration with A. Kolotushkin and V. Goessen, in 1987. Sphinx, an acronym for Super Functional Integrated Communication System (), was intended to be an ensemble of modules that would allow consumers to easily interact with information systems.
The home environment, as described in a 1987 issue of Soviet magazine Technical Aesthetics (), would be composed of "spherical speakers, a detachable monitor, headphones, a handheld remote control with a removable display, a diskette drive, a processor with three memory blocks and more". The modules were designed to be used collectively, or individually by family members, and the number of memory blocks was supposed to be possibly increased endlessly according to the needs of the household so different family members could activate different programs simultaneously.
According to Sergey Moiseyev, Head the VNIITE (Russian design research institute):
The configuration of the Sphinx station, with detachable monitors and speakers, prefigured the environment of computer stations with peripheral touch pads and accessories that characterises informatics systems in the beginnings of the 21st century.
References
Science and technology in the Soviet Union
History of computing
Product design | Sphinx (home automation system) | [
"Technology",
"Engineering"
] | 266 | [
"Product design",
"Design",
"Computers",
"History of computing"
] |
54,253,818 | https://en.wikipedia.org/wiki/Amphenone%20B | Amphenone B, or simply amphenone, also known as 3,3-bis(p-aminophenyl)butan-2-one, is an inhibitor of steroid hormone and thyroid hormone biosynthesis which was never marketed but has been used as a tool in scientific research to study corticosteroids and the adrenal glands. It acts as competitive inhibitor of 11β-hydroxylase, 17α-hydroxylase, 17,20-lyase, 21-hydroxylase, and 3β-hydroxysteroid dehydrogenase, as well as of cholesterol side-chain cleavage enzyme, thereby inhibiting the production of steroid hormones including glucocorticoids, mineralocorticoids, androgens, and estrogens. In addition, amphenone B inhibits the production of thyroxine by a thiouracil-like mechanism, specifically via inhibition of organic binding of iodine and uptake of iodide by the thyroid gland.
Amphenone B was first synthesized in 1950 and is a diphenylmethane derivative that was derived from the insecticide 2,2-di(p-chlorophenyl)-1,1-dichloroethane (p,p'-DDD), which in 1949 had been found to selectively induce adrenal atrophy. In contrast to p,p'-DDD, which has direct cytotoxic effects on the adrenal glands via an unknown mechanism, amphenone B does not have cytotoxic effects, and instead causes adrenal and thyroid gland hypertrophy due to respective inhibition of corticosteroid and thyroxine biosynthesis, subsequent loss of negative feedback on the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes, and consequent hypersecretion of adrenocorticotropic hormone (ACTH) and thyroid-stimulating hormone (TSH) from the pituitary gland.
Amphenone B has also been found to produce progesterone-like progestogenic effects, including uterine hypertrophy and mammary lobuloalveolar development. These effects occurred even in animals that had been ovariectomized and hypophysectomized, suggesting that amphenone B might be acting directly on the target organs. However, it was found that adrenalectomy abolished the progesterone-like effects of amphenone B on the uterus, whereas those of progesterone were retained in the same experimental conditions, supporting the notion that amphenone B was not actually acting directly on the uterus. Conversely, the progesterone-like effects of amphenone B on the mammary glands were found to persist even in adrenalectomized and ovariectomized animals.
Amphenone B was tested in humans in the mid-1950s as a potential treatment for cortisol-dependent conditions such as Cushing's syndrome and adrenocortical carcinoma. In healthy subjects and patients with adrenocortical carcinoma, the drug was found to be effective in decreasing circulating levels of corticosteroids including cortisol, corticosterone, and aldosterone, as well as in decreasing circulating levels of androgens and estrogens. Moreover, due to reduced aldosterone secretion, it caused marked diuresis and increased urinary sodium excretion. Unfortunately, amphenone B also caused many side effects, some severe, including drowsiness, gastrointestinal disturbances such as heartburn, nausea, and vomiting, morbilliform and pruritic rashes, methemoglobinemia, and hepatotoxicity including impaired liver function and hepatomegaly, and these toxicities, as well as the diversity of its effects on various organs (e.g., also possessing antithyroid and even anesthetic activity), precluded its therapeutic use.
Subsequently, analogues of amphenone B with reduced toxicity and improved specificity were developed. One of the most potent of these was metyrapone (2-methyl-1,2-di(pyridin-3-yl)propan-1-one), a selective inhibitor of 11β-hydroxylase, which was selected for clinical development and was eventually approved and marketed in 1958 as a diagnostic agent for Cushing's syndrome. Another was mitotane (o,p'-DDD, or 1,1-(dichlorodiphenyl)-2,2-dichloroethane), an inhibitor of cholesterol side-chain cleavage enzyme and to a lesser extent of other steroidogenic enzymes, which additionally has selective and direct cytotoxic effects on the adrenal glands similarly to p,p'-DDD, and was introduced in 1960 for the treatment of adrenocortical carcinoma. Aminoglutethimide (3-(4-aminophenyl)-3-ethylpiperidine-2,6-dione), which was originally introduced as an anticonvulsant in 1960, is closely related structurally to amphenone B, and following its introduction, was found to cause adrenal insufficiency in patients due to inhibition of cholesterol side-chain cleavage enzyme and suppression of corticosteroid production. The drug was subsequently repurposed for use in the treatment of metastatic breast cancer and Cushing's syndrome.
Amphenone B was originally thought to be 1,2-bis(p-aminophenyl)-2-methylpropan-1-one, but it was discovered in 1957 that the synthesis of amphenone B was accompanied by an unexpected molecular rearrangement and that the drug was actually 3,3-bis-(p-aminophenyl)butan-2-one. As such, early publications of amphenone B, and some subsequent publications, refer to the drug by the incorrect structure.
See also
Steroidogenesis inhibitor
References
11β-Hydroxylase inhibitors
21-Hydroxylase inhibitors
4-Aminophenyl compounds
Antiestrogens
Antiglucocorticoids
Antimineralocorticoids
Antithyroid drugs
CYP17A1 inhibitors
Hepatotoxins
Ketones
Nonsteroidal antiandrogens | Amphenone B | [
"Chemistry"
] | 1,375 | [
"Ketones",
"Functional groups"
] |
54,254,092 | https://en.wikipedia.org/wiki/Edgar%20Silinsh | Edgar Imant Silinsh (, , Edgar Aleksandrovich Silinsh; 21 March 1927 – 26 May 1998) was a Soviet and Latvian scientist in the field of semiconductor physics and philosophy of science, academician of the Latvian Academy of Sciences (1992).
Biography
Edgar Silinsh was born the 4th child in a family of prosperous farmer Aleksandrs Siliņš (1875—1934) on the "Veclapsas" farmstead in Līgatne municipality of Riga district. During his school years, he was mostly interested in literature and history rather than in physical sciences. Due to the start of World War II and the death of his mother in 1943, E. Silinsh was forced to discontinue his education; nevertheless, in 1946 he took secondary school exams and enrolled at the Faculty of Chemistry of the State University of Latvia (SUL). The choice for natural sciences was rooted in Edgar's awareness of humanities being ideologically constrained in the Soviet Union. Yet he was forced to cease his studies even in the field of chemistry during the Stalinist repressions of 1949, because of class-based mistreatment. After that, E. Silinsh worked as a laborant for 14 years, and for last 12 of these he was employed at the Central Laboratory of the Riga Plant of Electrical Machine Building (). At this institution, E. Silinsh could for the first time perform actual scientific research, mostly in the field of atomic spectroscopy. In 1958, his two messages were included in the X All-Union Spectroscopy Conference in Lvov. In total, Edgar Silinsh published 26 scientific and technical papers in the field of atomic and molecular spectroscopy during his years at RER, as well as 16 technical and technological publications of other kinds. During the "Khrushchev Thaw", Edgar Silinsh was finally able to enroll (in 1957) and graduate (in 1961) the Faculty of Physics and Mathematics of the University of Latvia. In 1962, he began his extramural studies for the Candidate of Sciences degree (equivalent to the Western PhD) at the S. Vavilov State Optical Institute in Leningrad and defended in June 1965. His Candidate thesis topic was influence of plasma and contact discharge on the emission spectra of metal atoms (doctoral advisor K. Taganov).
In 1963, the founder of Latvian Institute of Organic Synthesis Solomons Hillers proposed to create a joint research group of chemists and physicists in Riga to study electrophysical properties of organic compounds. Edgar Silinsh was appointed the head of this research group. Between 1963 and 1967 he was a researcher at the Laboratory of Semiconductor Physics Problems, SUL, whereas beginning with the year 1967 he led the Laboratory of Physics of Organic Semiconductors (later the Laboratory of Organic Solid State Physics and Molecular Electronics) at the Institute of Physical Energetics, Latvian Academy of Science. Until 1975, a new model was developed under his lead, describing the physical nature of local structure-determined charge-carrier trapping centers in organic molecular crystals. The most important publication of this period (71 Scopus citations) ushered in the collaboration with professor of the New York University Martin Pope and professor of Japanese National Institute of Natural Sciences , later also with professor of the University of West Bohemia in Plzeň, Stanislav Nešpůrek.
In the following years, Edgar Silinsh took interest in the problems of organic solid state energetics and proved that the conventional band theory is inapplicable to molecular solids. A new, improved phenomenological model was also developed to describe these peculiarities. In 1978, these conclusions were summarized in a monograph, year later E. Silinsh defended his Doctor of Science thesis (equivalent to Western habilitation) on the topic, and in 1980 the improved and updated monograph was published by Springer, now available for Western readers. The last one is the most cited work of Edgar Silinsh in his whole life (218 citations as of June 2017), and Silinsh himself was once credited as the most cited Latvian author.
In the early 1980s, Edgar Silinsh was interested particularly in photogeneration mechanisms in organic semiconductors. In 1985, E. Silinsh published the molecular polaron model describing the lattice polarization effect on charge carriers; together with coworkers A. Jurģis and G. Šlihta developed the modified Sano—Mozumder model to describe the transfer of charge-carriers in the molecular semiconductor. Scientific endeavor of Edgar Silinsh embraced vast collaboration with the chemists of Riga Polytechnical Institute (later Riga Technical University) led by professor O. Neilands, as well as with the chemists of the Latvian Institute of Organic Synthesis, led by professor J. Freimanis. Total number of Edgar Silinsh's publications and scientific reports exceeds 200, in addition to six monographs, talks at over 20 scientific conferences and more than 50 lectures in the scientific establishments abroad. He has 710 citations listed in Scopus and h-index of 15. Edgar Silinsh was a member of American Physical Society, the Rotary club and some other international organizations; since 1992 — full member of the Latvian Academy of Sciences (LAS).
Edgars Imants Siliņš died on 26 May 1998, and is buried at the Līgatne cemetery. In the same year, the Prize in the field of Physics devoted to him was established by the LAS. In 2004, in front of the Institute of Physical Energetics (Aizkraukles St. 21, Riga) a monument to Edgar Silinsh was erected, designed by sculptors Juris Rapa and Zigrīda Rapa.
Views and works in philosophy of science
Edgar Silinsh had much interest in Oriental philosophy (daoism, zen-buddhism), as well as in the traditional Japanese culture. He also revered the works of Niels Bohr in the field of philosophy of science, as well as (in the philosophical context) works of Dutch graphic artist Maurits Escher. In the year following the death of E. Silinsh, Jumava publishing house put in print his collection of essays on the matter, named "The Quest for the Great Truths" ().
List of monographs
О. Нейланд, Я. Страдынь, Э. Силиньш и др. Строение и таутомерные превращения β–дикарбонильных соединений. Зинатне: Рига, 1977, 444.с.
Э. Силиньш. Электронные состояния органических молекулярных кристаллов. Зинатне: Рига, 1978, 344.с.
E. A. Silinsh. Organic Molecular Crystals. Their Electronic States. Springer: Berlin/Heidelberg, 1980, 389 p.
В. Андреев, M. Kурик, С. Нешпурек, Э. Силиньш, И. Чaпек и др. (под общей редакцией Э. Силиньша). Электронные процессы в органических молекулярных кристаллах: Явление поляризации и локализации. Зинатне: Рига, 1988, 329.с.
Э. Силиньш, M. Kурик, И. Чaпек. Электронные процессы в органических молекулярных кристаллах: Перенос, захват, спиновые эффекты. Зинатне: Рига, 1992, 363.с.
E. Siliņš, V. Čapek. Organic Molecular Crystals: Interaction, Localization, and Transport Phenomena. AIP Press, New York, 1994, 402 p.
Lielo patiesību meklējumi. Esejas. Jumava: Rīga, 1999, 511 lpp. (Latvian)
Awards
Grand Medal of the Latvian Academy of Sciences "for establishing a new field and a school of physics of organic solid state, as well as for organizing efforts for the science of Latvia" (1997);
M. Keldysh Prize by Latvian SSR Academy of Science (1984);
An Edgar Silinsh Prize in Physics was established after his death in 1998 by the Latvian Academy of Sciences.
Quotes
Revealing the truth is the end in itself of the science, as well as the justification of its existence. Hence a scientist must never lie. Lies shatter confidence in the statements of another scientist. Whereas without this confidence, collective collaboration in science is impossible. (1971)
References
1927 births
1998 deaths
People from Cēsis Municipality
Latvian physicists
Semiconductor physicists
Theoretical physicists
Soviet physicists | Edgar Silinsh | [
"Physics"
] | 2,010 | [
"Theoretical physics",
"Theoretical physicists"
] |
54,254,209 | https://en.wikipedia.org/wiki/Benzyl%20iodide | Benzyl iodide is an organic compound with the chemical formula . The compound consists of a benzene ring with an attached iodidemethyl group. The substance is an alkyl halide and is a constitutional isomer of the iodotoluenes.
Synthesis
Benzyl iodide can be obtained via the Finkelstein reaction from benzyl chloride and sodium iodide in acetone.
Properties
Benzyl iodide forms colorless to yellow needles, melting at 24.5 °C. As a liquid, the compound has the high refractive index of 1.6334. Benzyl iodide is also a powerful lachrymator.
See also
Benzyl bromide
Benzyl chloride
Benzyl fluoride
References
Organoiodides
Benzyl compounds
Lachrymatory agents | Benzyl iodide | [
"Chemistry"
] | 164 | [
"Lachrymatory agents",
"Chemical weapons"
] |
54,255,225 | https://en.wikipedia.org/wiki/2017%20Bank%20of%20the%20Philippine%20Islands%20systems%20glitch | On June 7, 2017, the Bank of the Philippine Islands (BPI) suspended its online transaction and automatic teller machine services amidst reports of money missing from its account holders. There was speculation that BPI was compromised by hackers but the bank claimed that the problem was caused by an internal data processing error. The scope of the issue was nationwide according to the bank and also said that only a small portion of its customers were affected and that most of them were in Metro Manila.
It was reported that the value of some transactions made from April 27 to May 3, 2017, were doubled. The bank issued a statement that they were resolving the issue and assured that its clients would not lose any money.
BPI's stocks in the Philippine Stock Exchange remained unaffected in response to the incident. Luis Limlingan, head of research and sales at Regina Capital Development Corporation viewed that most investors could have seen the incident as a one-off event that could be resolved. According to Limlingan the real problem was how BPI dealt with its disgruntled customers.
BPI announced that they resolved the issue at 9 p.m. on June 8, 2017. The Bangko Sentral ng Pilipinas, the country's central bank, launched a probe on the incident.
See also
2012 RBS Group computer system problems
2021 Banco de Oro hack
References
2010s in economic history
June 2017 events in the Philippines
Software anomalies
Corporate scandals | 2017 Bank of the Philippine Islands systems glitch | [
"Technology"
] | 291 | [
"Computer errors",
"Technological failures",
"Software anomalies"
] |
54,256,008 | https://en.wikipedia.org/wiki/Choreocolax%20polysiphoniae | Choreocolax polysiphoniae is a minute marine parasitic alga in the division Rhodophyta.
Description
This small parasitic alga grows on the red alga Polysiphonia lanosa. It grows as an irregular sphere on the fronds of the alga, reaching no more than 1 mm in extent.
Habitat
Parasitic on Polysiphonia lanosa, the filaments grow into the host.
Distribution
The species has been reported from North Russia and the Pacific. In Ireland it has been confidently recorded from counties Down, Antrim and Waterford and at scattered sites around the British Isles including the Shetland Islands.
Reproduction
Cruciate tetrasporangia are produced all year round in the cortex. The gametangial are dioecious and are produced in spring and summer.
References
Ceramiales
Parasitic eukaryotes
Species described in 1875 | Choreocolax polysiphoniae | [
"Biology"
] | 178 | [
"Parasitic eukaryotes",
"Eukaryotes"
] |
54,256,085 | https://en.wikipedia.org/wiki/Weapons%20of%20Math%20Destruction | Weapons of Math Destruction is a 2016 American book about the societal impact of algorithms, written by Cathy O'Neil. It explores how some big data algorithms are increasingly used in ways that reinforce preexisting inequality. It was longlisted for the 2016 National Book Award for Nonfiction but did not make it through the shortlist. The book has been widely reviewed,
and won the Euler Book Prize.
Overview
O'Neil, a mathematician, analyses how the use of big data and algorithms in a variety of fields, including insurance, advertising, education, and policing, can lead to decisions that harm the poor, reinforce racism, and amplify inequality. According to National Book Foundation:
She posits that these problematic mathematical tools share three key features: they are opaque, unregulated, and difficult to contest. They are also scalable, thereby amplifying any inherent biases to affect increasingly larger populations. WMDs, or Weapons of Math Destruction, are mathematical algorithms that supposedly take human traits and quantify them, resulting in damaging effects and the perpetuation of bias against certain groups of people.
Reception
The book received widespread praise for elucidating the consequences of reliance on big data models for structuring socioeconomic resources. Clay Shirky from The New York Times Book Review said "O'Neil does a masterly job explaining the pervasiveness and risks of the algorithms that regulate our lives," while pointing out that "the section on solutions is weaker than the illustration of the problem". Kirkus Reviews praised the book for being "an unusually lucid and readable" discussion of a technical subject.
In 2019, the book won the Euler Book Prize of the Mathematical Association of America.
See also
Decomputing
Resisting AI
References
External links
Presentation by O'Neil on Weapons of Mass Destruction, September 20, 2016, C-SPAN
2016 non-fiction books
Books about race and ethnicity
English-language non-fiction books
American non-fiction books
Data activism
Crown Publishing Group books | Weapons of Math Destruction | [
"Technology"
] | 409 | [
"Data",
"Data activism"
] |
54,256,334 | https://en.wikipedia.org/wiki/Hager%20Group | Hager Group is a manufacturer of electrical installations in residential, commercial and industrial buildings based in Blieskastel, Germany. The company has been family-run and owned ever since its foundation in 1955.
Hager Group provides products and services ranging from energy distribution and cable management to intelligent building automation and security systems, under the brand Hager. Hager Group also owns the brands Berker, Bocchiotti, Daitem, Diagral, Elcom and E3/DC. In 2018, Hager Group was the world market leader in electrical installation systems. In August 2019, the group was ranked number 128 in the top 500 family-owned businesses in Germany according to the magazine Die Deutsche Wirtschaft.
History
In 1955, Hager oHG, elektrotechnische Fabrik was founded by brothers Oswald and Hermann Hager, together with their father Peter Hager in Ensheim in the Saarland region of Germany. Since 1945, Saarland had been under the economic control of France and had no access to the German market. However, Hager wanted to gain a foothold in both markets. In 1959, the Hager brothers founded their first foreign subsidiary, Hager Electro S. A., in Obernai, Alsace, in north-eastern France.
In 1966, Hager began systematical training of its electricians, whose expertise has created a culture of customer loyalty, something that continues to this day. Hager’s modular rotary fuse carrier was patented in Germany in 1968 and in France in 1970. At the same time, the first mass-produced distribution board, the Hager-Rapid-System, was launched on the French market. In 1973, Hager achieved sales of 43 million Deutsche Marks in Germany and in 1974 the company reached a turnover of 22 million francs in France.
In 1976, Hager launched the mini Gamma enclosure, in 1982 the company started producing the first Residual-current circuit breakers (RCCB) in Germany. A new production facility with a high-bay warehouse was opened in Blieskastel.
Hager Group began to market itself as a complete service provider for electrical installations in buildings in the 1980s, setting up sales companies in Europe (Switzerland and Great Britain). In the mid-1990s, Hager set up distribution channels in the United Arab Emirates (Dubai), Singapore, Malaysia, Hong Kong, China, Australia and New Zealand.
In 2007, Hager Group became a European Company: Hager SE.
Locations
Hager Group has 22 manufacturing sites in 10 countries across the world. Components for the respective markets are manufactured at the local production facilities in order to accommodate local installation requirements. The biggest production site is in Obernai, France. Hager Forum was established there in 2015 as a training and meeting place for partners, customers and employees of the company.
Acquisitions
In 1992, the group acquired Lumetal, a manufacturer of distribution boards from Porcia, Italy. Hager Group acquired the German company Tehalit in 1996, a manufacturer of cable management systems and cable ducts.
In 1998, the group acquired the French electronic timer manufacturer Flash, whose registered office was in Saverne. Prior to this, Hager Group manufactured only mechanical timers. The same year, the company also acquired British manufacturer Ashley & Rock from Ulverston, whose products were manufactured according to British Standards.
In 2002, the Polish company Polo, whose registered office was in Tychy, was integrated into the company, in 2004, Hager Group acquired Swiss company Weber AG and French manufacturer Atral. In addition to Hager brand security systems, Atral also manufactures products for the brands Diagral, Daitem and Logisty.
In 2006, Hager entered the Brazilian market when it acquired 100 % of the shares in Eletromar. Hager Group opened a plant in Pune, India in 2008 and on 30 September of the same year, the foundation stone for a new Eletromar production site in Brazil was laid. On 1 January 2009, Hager acquired Electraplan Solutions GmbH, and in 2010, Hager acquired Berker, a German manufacturer of switches, whose registered offices were in Schalksmühle and Ottfingen.
2012 Hager gained the German family firm Elcom, a producer of intercoms.
In 2018, it acquired E3/DC GmbH, a German developer of inverters and energy storage systems.
Brands and products
Hager brand offers services for electrical installations in residential, commercial and industrial buildings. In 2009, the previous brands Tehalit, Weber, Lume, Klik, Flash, Polo, Ashley & Rock and Logisty were combined under Hager brand. Alarms and security systems are sold under Daitem and Diagral. Berker manufactures switches and switch systems as part of Hager Group. Bocchiotti/Iboco, the Italian market leader in cable management and room distribution systems, is also part of Hager Group whilst Elcom produces intercom systems for residential and office buildings.
There are four different areas of application for Hager Group’s products and services:
Energy distribution and metering systems, including energy management and VDI concepts for electrical installation
Cable management systems for power and data distribution
Switch ranges and building control
Security systems
Since 2018, Hager Group has been working on electromobility with Audi AG. The aim of the collaboration is to connect the Audi e-Tron model with Hager Group’s Home Energy Management System (HEMS).
Brands
Bocchiotti/Iboco, Italian producer of room distribution systems
Berker, German brand for electrical installation applications, switches and switch systems
Daitem
Diagral
Corporate culture
6% of sales are invested in research and development. In 2019, the company filed around 3,000 patents. The group employs around 800 people in research and development, which mainly focuses on electromobility, intelligent building technology (for smart homes) and energy efficiency. Between October 2010 and June 2014, Hager Group sponsored football club 1. FC Saarbrücken, with a focus on promoting young talent. Since 2017, the group has been supporting the French football club Racing Club Strasbourg Alsace. This sponsorship lasts for three years.
References
Electronics companies of Germany
Security engineering
Security technology
Security equipment manufacturers
Energy technology
Energy engineering
German companies established in 1955
Electronics companies established in 1955
Companies based in Saarland
German brands | Hager Group | [
"Engineering"
] | 1,298 | [
"Systems engineering",
"Security engineering",
"Energy engineering"
] |
54,257,079 | https://en.wikipedia.org/wiki/NGC%207022 | NGC 7022 is a barred lenticular galaxy located about 95 million light-years away from Earth in the constellation Indus. The galaxy was discovered by astronomer John Herschel on October 2, 1834.
See also
Barred lenticular galaxy
List of NGC objects (7001–7840)
NGC 16
NGC 2787
References
External links
Barred lenticular galaxies
Indus (constellation)
7022
66224
Astronomical objects discovered in 1834 | NGC 7022 | [
"Astronomy"
] | 84 | [
"Indus (constellation)",
"Constellations"
] |
54,257,099 | https://en.wikipedia.org/wiki/266P/Christensen | 266P/Christensen is a periodic comet in the Solar System. It will next come to perihelion in December 2026. It has been suggested as the source of the 1977 "Wow! Signal".
References
External links
Orbital simulation from JPL (Java) / Horizons Ephemeris
266P on Seiichi Yoshida's comet list
Elements and Ephemeris for 266P/Christensen – Minor Planet Center
Periodic comets
0266
266P
20061027 | 266P/Christensen | [
"Astronomy"
] | 98 | [
"Astronomy stubs",
"Comet stubs"
] |
54,257,777 | https://en.wikipedia.org/wiki/List%20of%20Microsoft%20Surface%20accessories | The Microsoft Surface touchscreen Windows computers and interactive whiteboards designed and developed by Microsoft. Since its release in 2012, there have been various Surface accessories over the years. Most prominently, are the Surface keyboard covers and the Surface Pen, which were both introduced at launch. While the keyboard covers have all been sold independently of the Surface devices, the initial release of the Surface and Surface Pro had bundle options, which bundled the black Touch Cover. The Surface Pen has been included with all Surface line and Surface Pro line devices up until the release of the fifth-generation Surface Pro, where Microsoft decided to unbundle the Surface Pen.
Accessories
Surface Touch Cover
The original touch cover came with 80 touch sensors and was pressure sensitive. With the release of the Surface 2 a Touch Cover 2 was announced which increased the number of sensors to 1,092 and added backlit keys while being thinner than the original Touch Cover. In addition, the Touch Cover 2 also supported key gestures and was backwards compatible with the first generation Surface devices. Microsoft never made another Touch Cover after the release of the Surface Pro 3.
It is compatible with the Surface 2.
Type Cover
With the release of the first generation Surface Pro, Microsoft launched the Type Cover which has tactile keys. It was upgraded along with the second generation Surfaces to the Type Cover 2 which substituted the plastic material for the felt-like material found on the Type Covers. The Type Cover 2 is thinner and features back-lit keys. With the release of the Surface Pro 3, a newer cover called the Surface Pro 3 Type Cover was released to fit the bigger screen. The Surface Pro 3 Type Cover features a second magnetized strip that can be rested against the screen to prop the keyboard up at an angle. The Surface Pro 3 Type Cover has a touchpad with glass beads replacing the felt-like material used in previous generations. When the Surface 3 was announced, a smaller version, the Surface 3 Type Cover was released. Both Surface 3 and Pro 3 Type Covers have a loop to house the Surface Pen.
On October 6, 2015, Microsoft updated the Surface Pro Type Cover with a new teal color in addition to the existing black, red, blue, and bright blue colors. Also introduced was a function lock light, separated keys, and a 40% larger touchpad than previous models. A "Fingerprint ID" version was also announced but is only available in the color black. Both are backwards compatible with the Surface Pro 3, though both are designed for the Surface Pro 4. A Signature Type Cover designed out of grey Alcantara was announced on April 12, 2016.
With the launch of the fifth-generation Surface Pro, Microsoft expanded the Surface Pro Signature Type Cover line to include burgundy, cobalt blue, and platinum with a release date of June 15, 2017.
|Surface Pro 3Surface Pro 4Surface Pro (5th generation)Surface Pro 6
Power Cover
A Power Cover, introduced alongside the Surface Pro 2, is a non back-lit Type Cover with a built-in battery to extend the Surface's battery life. It is compatible with the Surface Pro and later, due to the additional pins required on the Surface spine. A Wireless Adapter for the keyboards, called the Wireless Adapter for Typing Covers, was also manufactured so that the keyboards can be used at a distance. It was introduced in September 2013 and has been discontinued on March 26, 2014.
Surface Keyboard
In 2018, Microsoft launched the Surface Keyboard alongside the Surface Mouse, which is compatible with any Bluetooth enabled device
Surface Mouse
Two mice have also been released for the Surface including the Wedge Touch and Arc Touch mice. On July 10, 2018, Microsoft launched the Surface Mouse alongside the Surface Keyboard. It is compatible with any Bluetooth-enabled device.
Surface Pen
Most Surface tablets have an active pen that allows users to write directly onto the screen of the tablet. The Surface Pen for the Surface Pro and Surface Pro 2 use Wacom technology, while its successor released alongside the Surface Pro 3 and newer devices use that of N-trig, which has since been acquired by Microsoft. The Surface Pen was specifically designed to minimize latency (lag time), eliminate parallax issues, which occur when the point where the tip touches the screen does not match up with the spot where the ink actually appears on the device, and provide a more natural-feeling 'pen-on-paper' user experience. The Surface also features palm rejection which allows the user to rest his or her palm on the screen while using the Surface Pen without triggering an unwanted input.
It is compatible with any Bluetooth-enabled device.
Surface Dock
There are various Docking Stations for different Surface Laptop devices, which are optional non-included accessories. They each extend the Surface with a number of USB ports, additional audio sockets, a Gigabit Ethernet port and a selection of ports to connect external displays. As of April 2023, while the only two discontinued Docks are for Surface Pro 1-3 and Surface 3, the latest model is the Surface Thunderbolt 4 Dock.
Prior Surface Docks (Surface Pro 1/2/3, Surface 3 only)
The initial design of the Surface Dock had a diagonal tablet stand permanently set at 60 degrees for the device to rest in while two arms slid together to secure the device and plug into all of the tablet ports. Of note, the Surface Dock for Surface 3 and Surface Pro 3 used a new 40-pin interconnect on the right arm of the dock to join the device to the docking station for charging and port replication use. The port featured in several generations of Surface Devices afterward.
Surface Dock (Brick)
With the announcement of the Surface Pro 4 and Surface Book, Microsoft revealed a new Surface Dock accessory in a brick form factor which is compatible with Surface 3 and the Surface Pro 3. This docking accessory connects to the proprietary 40-pin side port which got the new nameSurface Connect. Unlike the prior docks, the Surface Dock offered two Mini-DisplayPort outputs, but had a limit of SD/HD/2K video at 60Hz or 4K video at 30Hz, regardless of the screens used. Surface Dock compatibility includes all Pro devices from Surface Pro 3 up to and including Surface Pro 9. It also includes Surface Book 1 & 2, and all initial Surface Laptops, Surface Go, and Surface Laptop Go devices.
A Microsoft Garage incubator team designed ergonomic VESA-mounted portrait docking stations as part of the Company hackathon, released a YouTube demo video, open-source plans on GitHub, and made ready-to-use kits available on a web store.
Surface Dock 2
An update to the first brick Surface Dock, the Surface Dock 2 was released in 2021 and replaced the Mini-DP video outputs with USB-C DP-Alt Mode outputs. Devices starting with the Surface Book 3, Surface Pro 7-9, Surface Pro X, Surface Laptop 3-5 and Surface Laptop Studio all have 4K at 60Hz support on up to two displays with Surface Dock 2. It also offered the same compatibility to older devices that worked on Surface Dock 1, however, the same limitations in video output on Surface Dock 2 remained (2K at 60Hz, 4K at 30Hz) due largely to integrated video output limits on reduced voltage.
Surface Travel Hub
A USB-C "travel dock" was released at the same time as Surface Dock 2 with lower power usage and five ports: Ethernet, HDMI, VGA, USB-A and USB-C (charging limited to 12W.) Unlike the Surface Docks, the Travel Hub connects to Surface Devices with USB-C ports including the Surface Pro 7, Surface Book 2, Surface Go, Surface Laptop Go, Surface Laptop 3, and Surface Laptop Studio.
Surface Thunderbolt 4 Dock
The third brick Surface Dock was released in 2023, which introduced a new USB-C Upstream cable permanently attached to the dock to replace the 40-pin Surface Connect plug. This dock is compatible with select USB-C devices starting with Surface Pro 7-9, Surface Pro X, Surface Laptop 3-5, Surface Book 3, Surface Laptop Go 1-2, Surface Go 2-3, and Surface Laptop Studio. Not all of these devices actually offer Thunderbolt 4. Surface Laptop 5, Surface Pro 8-9 and Surface Laptop Studio are the only four devices with TB4/USB4 support.
Devices older than these models are not supported on the Surface Thunderbolt 4 Dock, notably the Surface Book 2 (which has a USB-C port that does not support Thunderbolt connectivity).
Surface Connect to USB-C Adapter
In addition to the Surface Dock, Microsoft has released a USB-C adapter that allows the Surface Pro and Surface Laptop to use generic USB-C docking stations with the Surface Connect port. The adapter, styled the same as the Surface Dock "brick" supports USB 3, Display Port alternate mode, and charging via USB Power Delivery. Charging requires USB power sources that output 12V, 15V, or 20V. Most cell phone and tablet chargers at the time did not support these voltage levels, however USB-PD Chargers sold today that offer at least 45W output are able to charge lower-voltage Surface devices while in use. The adapter could also maintain power to Surface Book models and Surface Laptop 3-5 while powered on (maximum USB-PD output to device is 40W).
Microsoft Wireless Display Adapter
Microsoft created and released the Wireless Display Adapter accessory in 2014 along with Surface 3 and Surface Pro 3 that uses Miracast (Wi-Fi Direct) to display an HDMI-quality Wireless Video connection from a Surface device. It also works any device that supports Miracast, including laptops that were formerly certified with Intel's WiDi technology.
The Wireless Display Adapter cannot transmit video from a desktop computer (or any other hardware not certified by Miracast before public sale) or on any device sold by a manufacturer who does not participate in the Miracast hardware standard. This includes all Apple laptops and devices, all Google Chromebooks, and Android devices starting with Android 8. However, individual handset manufacturers using Android can still certify a device to work with Miracast, such as Samsung's Galaxy S line.
To maintain HDCP support, devices that do not have current software driver updates will not connect to the Wireless Display Adapter (even if Miracast is supported).
Version 1 (long HDMI stick and short USB dongle) was released in 2014, which supported 1080p video at 30fps wirelessly, and HDMI-CEC control to automatically power on a TV and change input to the adapter when used.
Version 2 (HDMI and USB dongles both equal length, clear cap to plug both into each other for storage) released in 2016 added 1080/60fps support, control modes for gaming, video and work settings, and control channel support on touchpanel IFP displays such as ViewSonic, Benq, and Promethean (touchscreen input can control a Miracast device wirelessly from the display same as mouse/pen input.)
Version 3 (rectangular with individual HDMI and USB wires) was made available in 2020 with a longer USB wire to enable better reach on TVs with USB ports further away from HDMI input. Version 3 also added 4K support (3840x2160 at 30fps).
Surface Dial
With the introduction of the Surface Studio on 26 October 2016, Microsoft announced a new type of computing device called the Surface Dial. The promoted Surface Dial's purpose is to be used to control functions that artists might find useful, such as pen color or thickness. The Surface Dial is set with standard commands that can be used without being program or app specific. These commands include toggling sound volume, scrolling, zooming, brightness, and undo/redo. However, an app developer can customize the wheel's abilities, when developing apps. Some third-party applications that were included in the Surface Dial launch include Drawboard PDF, Sketchable, StaffPad and Mental Canvas Player. The Surface Dial works on the screen of the Surface Studio, Surface Book 2 and Surface Pro 2017 and off-screen with other Windows 10 devices (that support Bluetooth 4.0 LE) as well including the Surface Book and Surface Pro 4. Microsoft's Terry Myerson told Engadget that a firmware update will be released in early-2017 for the Surface Book and Surface Pro 4 that will allow the on-screen functions to work with those devices.
Surface Dial, like the Surface Pen, utilize non-rechargeable batteries, though the Dial requires the two included AAA alkaline batteries, and the Surface Pen requires a single AAAA battery. Surface Dial requires the Windows 10 "Anniversary Update" in order to function.
The Dial is compatible with the Surface Pro 4, Surface Studio, Surface Pro (2017), and Surface Book 2.
Surface Headphones
On October 2, 2018, Microsoft unveiled Bluetooth-compatible Surface Headphones alongside the Surface Pro 6, Surface Laptop 2 and Surface Studio 2. The noise-cancelling Bluetooth headphones feature Cortana integration and four beam-forming microphones.
On August 15, 2020, Microsoft introduced Surface Headphones 2, compatible with Windows 10 and Windows 11 Home/Pro with the latest updates. It's also compatible with Bluetooth 4.1/4.2/5.0, IOS 12 or 13, Android 9 or 10.
Surface Earbuds
Microsoft released wireless earbuds in 2019 that feature a "dish-looking apparatus" on the outside for touch interactions. The earbuds can also live transcribe a PowerPoint presentation from a connected computer. Like the aforementioned headphones, these are compatible to Bluetooth.
Other accessories
There are many other accessories for the Microsoft Surface.
Microsoft launched a Surface HD Digital A/V Adapter which works with micro-HDMI to HDMI for the Surface and Surface 2, and a Surface VGA adapter which also works with Surface and Surface 2 going from the built-in micro-HDMI to VGA.
For the Surface Pro series, a Display Port to HD A/V (HDMI) and a Display Port to VGA adapter was created. For the first generation Surface, a 32 watt power supply was included, which was upgraded with the Surface 2 to feature a larger indicator light to show the Surface was charging. The Surface Pro and Pro 2 feature a 48 watt power supply with a USB (power only) port on the charging brick. As with the Surface 2's power supply, the Pro 2's power supply features a larger indicator light. Microsoft redesigned the power supply for the Surface Pro 3 with a new "fin" connector and a 36 watt rating.
The Surface 3 launched with another redesigned power supply using a micro-USB connector and having a 13 watt rating.
Two Ethernet adapters have been released to work with the Surface Pro line including the Ethernet Adapter for USB 2.0 with a speed rating of 100 Mbit/s and a Surface Ethernet Adapter for USB 3.0 with a speed of 1 Gbit/s.
For the Surface Pro 8 series and newer devices, a Surface Slim Pen Charging Cradle has been released for users to charge the slim pen without a Touch Keyboard attached. The charger uses USB-C at the base. The cradle charges a Slim Pen wirelessly with any USB-PD charging adapter that is capable of at least 5W.
References
External links
Microsoft Surface
Surface accessories
Microsoft | List of Microsoft Surface accessories | [
"Technology"
] | 3,162 | [
"Computing-related lists",
"Microsoft lists"
] |
54,258,034 | https://en.wikipedia.org/wiki/335P/Gibbs | 335P/Gibbs is a periodic comet in the Solar System. It last came to perihelion in August 2022. Together with 266P/Christensen, it was proposed as the source of the 1977 "Wow! Signal".
References
External links
Orbital simulation from JPL (Java) / Horizons Ephemeris
335P on Seiichi Yoshida's comet list
Elements and Ephemeris for 335P/Gibbs – Minor Planet Center
Periodic comets
0335
335P
20081231 | 335P/Gibbs | [
"Astronomy"
] | 103 | [
"Astronomy stubs",
"Comet stubs"
] |
54,258,115 | https://en.wikipedia.org/wiki/Diploporita | Diploporita is an extinct group of blastozoans that ranged from the Ordovician to the Devonian. These echinoderms are identified by a specialized respiratory structure, called diplopores. Diplopores are a double pore system that sit within a depression on a single thecal (body) plate; each plate can contain numerous diplopore pairs.
Taxonomy
While once considered to be a formal class, the diploporitans likely represent a polyphyletic group. The evidence for this claim lies within the highly morphologically diverse body plans of the diploporitans: there are major differences in the makeup of the attachment structure (e.g., stem or holdfast), in the makeup of the feeding grooves, and even major differences in the construction of the group-defining diplopore respiratory structures.
As of 2019 the only available phylogenetic analysis of Diploporita to date indicates that Diploporita is not a natural evolutionary group. Rather, it is an artificial grouping based on the presence of diplopores, that have re-evolved multiple times throughout the echinoderm evolutionary tree.
Ancestry
At this time, it is not clear to which group Diploporita is most closely related. It has been suggested that the paraphyletic group Eocrinoidea could have given rise to diploporitans, as well as other groups of blastozoans, but the evidence for this is inconclusive at this time.
Major sub-groups
There are three major groups of Diploporita that have been traditionally proposed: the Asteroblastida, Glyptosphaeritida, and the Sphaeronitida. These three groups, which are markedly different from one another, are found in approximately the same age strata in the Early Ordovician of the Prague Basin.
Of these proposed groups, only one has been thought to be monophyletic: the Sphaeronitida. This group is characterized by short ambulacral feeding grooves and holdfasts that cement directly to a hard substrate, instead of a stem.
The following cladogram, representing a strict consensus of the 18 most parsimonious trees with a length of 99 steps, shows the monophyly of Sphaeronitida and (within it) Holocystidae. Most of the glyptosphaeritids shown are paraphyletic with respect to the sphaeronitids, and are in a polytomy with the representative of the paracrinoids and a complex clade. This complex clade includes a branch of rhombiferans, blastoids, parabloastoids (as sister to the lone asteroblastid diploporitan available for the study), and crinoids (as sister to an additoinal glyptosphaeritid diploporitan). Two eocrinoids form the outgroup, with the ascocystitid eocrinoid closer to the diploporitans than the gogiid.
{{barlabel|style=font-size:85%;line-height:85%;
|size=28
|at1=2.5 |bar1=purple |label1=Asteroblastid Diploporitan
|at2=5 |bar2=indigo |label2=Glyptosphaeritid Diploporitan
|at3=11 |bar3=indigo |label3=Glyptosphaeritid Diploporitans
|cladogram={{clade
|1=Gogia spiralus (Gogiid Eocrinoid)
|2={{clade
|1=Rhopalocystis destombesi (Ascocystitid Eocrinoid)
|2={{clade
|1=
|2=Canadocystis barrandei (Paracrinoid)
|3=Dactylocystis schmidti |barbegin3=indigo
|4=Fungocystites rarissimus |bar4=indigo
|5=Estonocystis antropoffi |bar5=indigo
|6=Glyptosphaerites leuchtenbergi |bar6=indigo
|7={{clade
|1=Tristomiocystis globossus |barend1=indigo
|label2=Sphaeronitida
|sublabel2=
|2=}} }} }} }} }}
Distribution
Information concerning the distribution of diploporitan fossils is constantly changing, as more field sites are found and fossils from these are described. This description of diploporitan fossil occurrences is only meant to be a general introduction and is not an exhaustive list.
Ordovician
Diploporitans in the Ordovician were very diverse, with one source noting 168 species. Diploporitans are routinely found preserved from the Ordovician in Gondwana (i.e., southern Europe, northern Africa, the Middle East), Baltica, South China, and European Laurentia (e.g., United Kingdom). Ordovician occurrences of diploporitans in North American Laurentia are limited to only a very small number of instances. The Late Ordovician Bromide Formation is one of the few, and likely the most well-known, outcrops of diploporitan fossils, Eumorphocystis multiporata.
Silurian
The end-Ordovician extinction represented a large-scale extinction for diploporitans. The majority of diploporitan species went extinct during this period and they never returned to their high species numbers after this time. During the Silurian, there was a much larger presence of diploporitans in North American than during the Ordovician. These diploporitans, called the Holocystites Fauna, appeared in North America during the middle of the Silurian. These diploporitans, representing multiple genera, all share the same basic features: reduced food grooves, large plates to support feeding structures that branched off of the surface of the body, and specialized diplopore respiratory structures, called humatipores (diplopores that are connected by multiple canals below the surface of the plate). The Holocystites Fauna is mostly found in the midcontinental United States (e.g., Indiana, Wisconsin, Tennessee) and does not survive past the end of the Silurian.
Other Silurian occurrences of diploporitans worldwide are rare and limited to only a few species (e.g., Eucystis''). These occurrences are largely restricted to southern Europe.
Devonian
Devonian occurrences of diploporitans are also quite rare. Most examples of this are, similar to the Silurian, limited to a few species in southern Europe. It was thought that diploporitans likely went extinct during the Early Devonian. However, a recent discovery found a new genus of diploporitan from the Middle Devonian, 50 million years after the last known diploporitan occurrence, in Kentucky, USA (Laurentia)
References
Works cited
Blastozoa
Polyphyletic groups
Fossil taxa described in 1854 | Diploporita | [
"Biology"
] | 1,531 | [
"Phylogenetics",
"Polyphyletic groups"
] |
67,094,287 | https://en.wikipedia.org/wiki/Dye-ligand%20affinity%20chromatography | Dye-ligand affinity chromatography is one of the Affinity chromatography techniques used for protein purification of a complex mixture. Like general chromatography, but using dyes to apply on a support matrix of a column as the stationary phase that will allow a range of proteins with similar active sites to bind to, refers to as pseudo-affinity. Synthetic dyes are used to mimic substrates or cofactors binding to the active sites of proteins which can be further enhanced to target more specific proteins. Follow with washing, the process of removing other non-target molecules, then eluting out target proteins out by changing pH or manipulate the salt concentration. The column can be reused many times due to the stability of immobilized dyes. It can carry out in a conventional way by using as a packed column, or in high-performance liquid chromatography (HPLC) column.
Discovery
The discovery of dye-ligand ability is from a blue dye called blue dextran. The blue dye is used as a void volume (V0) marker for a gel filtration column. It has shown that the dye has a property to bind to some certain proteins like pyruvate kinase and elute out with the void volume. Later on, it was found that "cibacron blue FG3-A", reactive dye link to dextran, is responsible for the interaction with the proteins.
Dye immobilization
The dyes are immobilized on the column matrix effectively, since usually the dyes link to a monochlorotriazine or dichlorotriazine ring (triazine dye). This type of dyes works especially well on a support matrix with hydroxyl group. The commonly used supporting matrix would be cross-linked agarose (sepharose), sephadex, polyacrylamide, and silica.
An example for triazine linkage immobilization is Blue Sepharose, resulting from Cibacron blue FG3-A with monochlorotriazine covalently coupled with OH group of sepharose. This reaction form an ether linkage and also hydrogen chloride.
C29H20ClN7O11S3 + C24H38O19 → C53H57N7O30S3 + HCl
Cibacron Blue FG3-A + Sepharose → Blue Sepharose + HCl
Reactive dyes
The dyes used in this type of chromatography are inexpensive and generally available as they are from textile industries called reactive dye. It contains chromophores that are often attached to a triazine ring. In textile industries, reactive dyes are used to dye material like cotton which is cellulose.
Commonly used reactive dyes for chromatography can be separated according to their color index name or functional group. Noted that each company has different trade names and slightly different formulas of the reactive dyes. Usually available commercially with sepharose as the supporting matrix in the form of packed columns.
Blue reactive dyes
Cibacron Blue F3GA
Cibacron Blue F3GA, Procion Blue HB, or Reactive blue 2 is a purinergic receptor antagonist, such as P2Y purinoceptor, and also an ATP receptor channels antagonist. It has a formula of C29H20ClN7O11S3 and a molecular weight of 774.2 g/mol. Cibacron blue is soluble in water and DMSO, however insoluble in ethanol. In water, saturated concentration is reached at 12.92 mM with the help of sonication. Cibacron Blue F3GA has a wide specificity for nucleotide-binding proteins or just a stereoselectivity electrostatic binding. It can be used to purify interferons, dehydrogenases, kinases, and serum albumin. For example, interferon purification from human gingival fibroblast extract using Cibacron Blue F3G-A on poly(2-hydroxyethyl methacrylate), the supporting matrix, in the form of cryogels. It has shown 97.6% purity of interferon.
Blue MX-R
Blue MX-R or Reactive Blue 4 has a formula of C23H14Cl2N6O8S2 and a molecular weight of 637.4 g/mol. It contains dichlorotriazine ring to the chromophore unlike Cibacron Blue F3GA. For a large scale protein purification, Blue MX-R can be used to purify protein such as lactate dehydrogenase (LDH). In fast-protein liquid chromatography (FPLC) using Blue MX-R immobilized on poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads, it was seen to separate lysozyme and bovine serum albumin (BSA), purified lysozyme from chicken albumin.
Red reactive dyes
Red HE-3B
Red HE-3B or Reactive Red 120 has a formula of C44H30Cl2N14O20S6 and a molecular weight of 1338.1 g/mol, containing two monochlorotriazine rings. It is highly soluble in water. The dehydrogenases binding ability of Red HE-3B is greater to NADP+ dependent dehydrogenases than NAD+ dependent dehydrogenases, vice versa for Cibacron Blue F3G-A. It can be used to purify enterotoxins A, B, and C2 from Staphylococcus aureus using Procion Red HE-3B on sepharose, eluting out with 60 mM and 150 mM phosphate.
Yellow reactive dyes
Yellow H-A
Yellow H-A or Reactive Yellow 3 has a formula of C21H17ClN8O7S2 and a molecular weight of 593 g/mol, containing a monochlorotriazine ring. On agarose as supporting matrix, it was seen to purify cholesteryl ester transfer protein.
Brown reactive dyes
Brown MX-5BR
Brown MX-5BR or Reactive Brown 10 has a formula of C40H19Cl4CrN12Na2O12S2 and a molecular weight of 1163.6 g/mol, containing two dichlorotriazine rings. Brown MX-5BR, for example, can be used to purify lysozyme, phosphinothricin acetyltransferase. It also shown that it can elute tryptophanyl-tRNA synthetase using Trp as eluant, however, tryptophanyl-tRNA and tyrosyl-tRNA synthetase are the only t-RNA that can be elute out using Brown MX-5BR.
References
Chromatography | Dye-ligand affinity chromatography | [
"Chemistry"
] | 1,479 | [
"Chromatography",
"Separation processes"
] |
67,094,405 | https://en.wikipedia.org/wiki/Comparison%20of%20user%20features%20of%20operating%20systems | Comparison of user features of operating systems refers to a comparison of the general user features of major operating systems in a narrative format. It does not encompass a full exhaustive comparison or description of all technical details of all operating systems. It is a comparison of basic roles and the most prominent features. It also includes the most important features of the operating system's origins, historical development, and role.
Overview
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers.
, the dominant general-purpose desktop operating system is Microsoft Windows with a market share of around 72.91%. macOS by Apple Inc. is in second place (14.93%), and the varieties of Linux are collectively in third place (4.04%). In the mobile sector, including both smartphones and tablets, Android is dominant with a market share of 71%, followed by Apple's iOS with 28%; for smartphones alone, Android has 72% and iOS has 28%. Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems (special-purpose operating systems)), such as embedded and real-time systems, exist for many applications. Security-focused operating systems also exist. Some operating systems have low system requirements (i.e. light-weight Linux distribution). Others may have higher system requirements.
Some operating systems require installation or may come pre-installed with purchased computers (OEM-installation), whereas others may run directly from media (i.e. live cd) or flash memory (i.e. USB stick).
MS-DOS
Overview
MS-DOS (acronym for Microsoft Disk Operating System) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and some operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS" (which is also the generic acronym for disk operating system). MS-DOS was the main operating system for IBM PC compatible personal computers during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
IBM licensed and re-released it in 1981 as PC DOS 1.0 for use in its PCs. Although MS-DOS and PC DOS were initially developed in parallel by Microsoft and IBM, the two products diverged after twelve years, in 1993, with recognizable differences in compatibility, syntax, and capabilities.
During its lifetime, several competing products were released for the x86 platform, and MS-DOS went through eight versions, until development ceased in 2000. Initially, MS-DOS was targeted at Intel 8086 processors running on computer hardware using floppy disks to store and access not only the operating system, but application software and user data as well. Progressive version releases delivered support for other mass storage media in ever greater sizes and formats, along with added feature support for newer processors and rapidly evolving computer architectures. Ultimately, it was the key product in Microsoft's development from a programming language company to a diverse software development firm, providing the company with essential revenue and marketing resources. It was also the underlying basic operating system on which early versions of Windows ran as a GUI.
Microsoft Windows
Overview
Microsoft Windows, commonly referred to as Windows, is a group of several proprietary graphical operating system families, all of which are developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. Active Microsoft Windows families include Windows NT and Windows IoT; these may encompass subfamilies, (e.g. Windows Server or Windows Embedded Compact) (Windows CE). Defunct Microsoft Windows families include Windows 9x, Windows Mobile, and Windows Phone.
Microsoft announced an operating environment named Windows on 10 November 1983, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs); Windows 1.0 first shipped on 20 November 1985. Microsoft Windows came to dominate the world's personal computer (PC) market with over 90% market share, overtaking Mac OS, which had been introduced in 1984, while Microsoft has in 2020 lost its dominance of the consumer operating system market, with Windows down to 30%, lower than Apple's 31% mobile-only share (65% for desktop operating systems only, i.e. "PCs" vs. Apple's 28% desktop share) in its home market, the US, and 32% globally (77% for desktops), where Google's Android leads.
Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh (eventually settled in court in Microsoft's favor in 1993). , on PCs, Windows is still the most popular operating system in all countries. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold. This comparison, however, may not be fully relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows (that are comparable to competitors) show one third market share, similar to that for end user use.
, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10, version 20H2. The most recent version for server computers is Windows Server, version 20H2. A specialized version of Windows also runs on the Xbox One video game console.
Windows 95
Windows 95 introduced a redesigned shell based around a desktop metaphor; File shortcuts (also known as shell links) were introduced and the desktop was re-purposed to hold shortcuts to applications, files and folders, reminiscent of Mac OS.
In Windows 3.1 the desktop was used to display icons of running applications. In Windows 95, the currently running applications were displayed as buttons on a taskbar across the bottom of the screen. The taskbar also contained a notification area used to display icons for background applications, a volume control and the current time.
The Start menu, invoked by clicking the "Start" button on the taskbar or by pressing the Windows key, was introduced as an additional means of launching applications or opening documents. While maintaining the program groups used by its predecessor Program Manager, it also displayed applications within cascading sub-menus.
The previous File Manager program was replaced by Windows Explorer and the Explorer-based Control Panel and several other special folders were added such as My Computer, Dial Up Networking, Recycle Bin, Network Neighborhood, My Documents, Recent documents, Fonts, Printers, and My Briefcase among others. AutoRun was introduced for CD drives.
The user interface looked dramatically different from prior versions of Windows, but its design language did not have a special name like Metro, Aqua or Material Design. Internally it was called "the new shell" and later simply "the shell". The subproject within Microsoft to develop the new shell was internally known as "Stimpy".
In 1994, Microsoft designers Mark Malamud and Erik Gavriluk approached Brian Eno to compose music for the Windows 95 project. The result was the six-second start-up music-sound of the Windows 95 operating system, The Microsoft Sound and it was first released as a startup sound in May 1995 on Windows 95 May Test Release build 468.
When released for Windows 95 and Windows NT 4.0, Internet Explorer 4 came with an optional Windows Desktop Update, which modified the shell to provide several additional updates to Windows Explorer, including a Quick Launch toolbar, and new features integrated with Internet Explorer, such as Active Desktop (which allowed Internet content to be displayed directly on the desktop).
Some of the user interface elements introduced in Windows 95, such as the desktop, taskbar, Start menu and Windows Explorer file manager, remained fundamentally unchanged on future versions of Windows.
Windows 10
A new iteration of the Start menu is used on the Windows 10 desktop, with a list of places and other options on the left side, and tiles representing applications on the right. The menu can be resized, and expanded into a full-screen display, which is the default option in Tablet mode. A new virtual desktop system was added. A feature known as Task View displays all open windows and allows users to switch between them, or switch between multiple workspaces. Universal apps, which previously could be used only in full screen mode, can now be used in self-contained windows similarly to other programs. Program windows can now be snapped to quadrants of the screen by dragging them to the corner. When a window is snapped to one side of the screen, Task View appears and the user is prompted to choose a second window to fill the unused side of the screen (called "Snap Assist"). Windows' system icons were also changed.
Charms have been removed; their functionality in universal apps is accessed from an App commands menu on their title bar. In its place is Action Center, which displays notifications and settings toggles. It is accessed by clicking an icon in the notification area, or dragging from the right of the screen. Notifications can be synced between multiple devices. The Settings app (formerly PC Settings) was refreshed and now includes more options that were previously exclusive to the desktop Control Panel.
Windows 10 is designed to adapt its user interface based on the type of device being used and available input methods. It offers two separate user interface modes: a user interface optimized for mouse and keyboard, and a "Tablet mode" designed for touchscreens. Users can toggle between these two modes at any time, and Windows can prompt or automatically switch when certain events occur, such as disabling Tablet mode on a tablet if a keyboard or mouse is plugged in, or when a 2-in-1 PC is switched to its laptop state. In Tablet mode, programs default to a maximized view, and the taskbar contains a back button and hides buttons for opened or pinned programs by default; Task View is used instead to switch between programs. The full screen Start menu is used in this mode, similarly to Windows 8, but scrolls vertically instead of horizontally.
Apple Macintosh
Apple Classic MacOS
Overview
The classic Mac OS (System Software) is the series of operating systems developed for the Macintosh family of personal computers by Apple Inc. from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The Macintosh operating system is credited with having popularized the graphical user interface concept. It was included with every Macintosh that was sold during the era in which it was developed, and many updates to the system software were done in conjunction with the introduction of new Macintosh systems.
Apple released the original Macintosh on 24 January 1984. The first version of the system software, which had no official name, was partially based on the Lisa OS, which Apple previously released for the Lisa computer in 1983. As part of an agreement allowing Xerox to buy shares in Apple at a favorable price, it also used concepts from the Xerox PARC Alto computer, which former Apple CEO Steve Jobs and other Lisa team members had previewed. This operating system consisted of the Macintosh Toolbox ROM and the "System Folder", a set of files that were loaded from disk. The name Macintosh System Software came into use in 1987 with System 5. Apple rebranded the system as Mac OS in 1996, starting officially with version 7.6, due in part to its Macintosh clone program. That program ended after the release of Mac OS 8 in 1997. The last major release of the system was Mac OS 9 in 1999.
Initial versions of the System Software ran one application at a time. With the Macintosh 512K, a system extension called the Switcher was developed to use this additional memory to allow multiple programs to remain loaded. The software of each loaded program used the memory exclusively; only when activated by the Switcher did the program appear, even the Finder's desktop. With the Switcher, the now familiar Clipboard feature allowed cut and paste between the loaded programs across switches including the desktop.
With the introduction of System 5, a cooperative multitasking extension called MultiFinder was added, which allowed content in windows of each program to remain in a layered view over the desktop, and was later integrated into System 7 as part of the operating system along with support for virtual memory. By the mid-1990s, however, contemporary operating systems such as Windows NT, OS/2, and NeXTSTEP had all brought pre-emptive multitasking, protected memory, access controls, and multi-user capabilities to desktop computers, The Macintosh's limited memory management and susceptibility to conflicts among extensions that provide additional functionality, such as networking or support for a particular device, led to significant criticism of the operating system, and was a factor in Apple's declining market share at the time.
After two aborted attempts at creating a successor to the Macintosh System Software called Taligent and Copland, and a four-year development effort spearheaded by Steve Jobs' return to Apple in 1997, Apple replaced Mac OS with a new operating system in 2001 named Mac OS X; the X signifying the underlying Unix system family base shared with Jobs' development of the NeXTSTEP operating systems on the NeXT computer. It retained most of the user interface design elements of the classic Mac OS, and there was some overlap of application frameworks for compatibility, but the two operating systems otherwise have completely different origins and architectures.
The final updates to Mac OS 9 released in 2001 provided interoperability with Mac OS X. The name "Classic" that now signifies the historical Mac OS as a whole is a reference to the Classic Environment, a compatibility layer that helped ease the transition to Mac OS X (now macOS).
Apple macOS
Overview
macOS (previously Mac OS X and later OS X) is a series of proprietary graphical operating systems developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS, after Microsoft Windows.
macOS is the direct successor to the classic Mac OS, the line of Macintosh operating systems with nine releases from 1984 to 1999. macOS adopted the Unix kernel and inherited technologies developed between 1985 and 1997 at NeXT, the company that Apple co-founder Steve Jobs created after leaving Apple in 1985. Releases from Mac OS X 10.5 Leopard and thereafter are UNIX 03 certified. Apple's mobile operating system, iOS, has been considered a variant of macOS.
Mac OS X 10.0 (code named Cheetah) was the first major release and version of macOS, Apple's desktop and server operating system. Mac OS X 10.0 was released on 24 March 2001 for a price of US$129. It was the successor of the Mac OS X Public Beta and the predecessor of Mac OS X 10.1 (code named Puma).
Mac OS X 10.0 was a radical departure from the classic Mac OS and was Apple's long-awaited answer for a next generation Macintosh operating system. It introduced a brand new code base completely separate from Mac OS 9's as well as all previous Apple operating systems, and had a new Unix-like core, Darwin, which features a new memory management system. Unlike releases of Mac OS X 10.2 to 10.8, the operating system was not externally marketed with the name of a big cat.
Apple MacOS Components
The Finder is a file browser allowing quick access to all areas of the computer, which has been modified throughout subsequent releases of macOS. Quick Look has been part of the Finder since version 10.5. It allows for dynamic previews of files, including videos and multi-page documents without opening any other applications. Spotlight, a file searching technology which has been integrated into the Finder since version 10.4, allows rapid real-time searches of data files; mail messages; photos; and other information based on item properties (metadata) and/or content. macOS makes use of a Dock, which holds file and folder shortcuts as well as minimized windows.
Apple added Exposé in version 10.3 (called Mission Control since version 10.7), a feature which includes three functions to help accessibility between windows and desktop. Its functions are to instantly display all open windows as thumbnails for easy navigation to different tasks, display all open windows as thumbnails from the current application, and hide all windows to access the desktop. FileVault is optional encryption of the user's files with the 128-bit Advanced Encryption Standard (AES-128).
Features introduced in version 10.4 include Automator, an application designed to create an automatic workflow for different tasks; Dashboard, a full-screen group of small applications called desktop widgets that can be called up and dismissed in one keystroke; and Front Row, a media viewer interface accessed by the Apple Remote. Sync Services allows applications to access a centralized extensible database for various elements of user data, including calendar and contact items. The operating system then managed conflicting edits and data consistency.
All system icons are scalable up to 512×512 pixels as of version 10.5 to accommodate various places where they appear in larger size, including for example the Cover Flow view, a three-dimensional graphical user interface included with iTunes, the Finder, and other Apple products for visually skimming through files and digital media libraries via cover artwork. That version also introduced Spaces, a virtual desktop implementation which enables the user to have more than one desktop and display them in an Exposé-like interface; an automatic backup technology called Time Machine, which allows users to view and restore previous versions of files and application data; and Screen Sharing was built in for the first time.
In more recent releases, Apple has developed support for emoji characters by including the proprietary Apple Color Emoji font. Apple has also connected macOS with social networks such as Twitter and Facebook through the addition of share buttons for content such as pictures and text. Apple has brought several applications and features that originally debuted in iOS, its mobile operating system, to macOS in recent releases, notably the intelligent personal assistant Siri, which was introduced in version 10.12 of macOS.
Unix and Unix-like systems
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.
Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley (BSD), Microsoft (Xenix), Sun Microsystems (SunOS/Solaris), HP/HPE (HP-UX), and IBM (AIX). In the early 1990s, AT&T sold its rights in Unix to Novell, which then sold its Unix business to the Santa Cruz Operation (SCO) in 1995. The UNIX trademark passed to The Open Group, an industry consortium founded in 1996, which allows the use of the mark for certified operating systems that comply with the Single UNIX Specification (SUS). However, Novell continues to own the Unix copyrights, which the SCO Group, Inc. v. Novell, Inc. court case (2010) confirmed.
Unix systems are characterized by a modular design that is sometimes called the "Unix philosophy". According to this philosophy, the operating system should provide a set of simple tools, each of which performs a limited, well-defined function. A unified filesystem (the Unix filesystem) and an inter-process communication mechanism known as "pipes" serve as the main means of communication, and a shell scripting and command language (the Unix shell) is used to combine the tools to perform complex workflows.
Unix distinguishes itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language, which allows Unix to operate on numerous platforms.
macOS, described above, is a Unix-like system, and, beginning with Mac OS X Leopard, is certified to comply with the SUS.
Linux
Linux is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on 17 September 1991, by Linus Torvalds. Linux is typically packaged in a Linux distribution.
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy.
Popular Linux distributions include Debian, Fedora, and Ubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers may omit graphics altogether, or include a solution stack such as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any purpose.
Linux was originally developed for personal computers based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system. Because of the dominance of the Linux-based Android on smartphones, , Linux also has the largest installed base of all general-purpose operating systems. Although it is, , used by only around 2.9 percent of desktop computers, the Chromebook, which runs the Linux kernel-based ChromeOS, dominates the US K–12 education market and represents nearly 20 percent of sub-$300 notebook sales in the US. Linux is the leading operating system on servers (over 96.4% of the top 1 million web servers' operating systems are Linux), leads other large systems such as mainframe computers, and is the only OS used on TOP500 supercomputers (since November 2017, having gradually eliminated all competitors).
Linux also runs on embedded systems, i.e. devices whose operating system is typically built into the firmware and is highly tailored to the system. This includes routers, automation controls, smart home technology (such as Google Nest), televisions (Samsung and LG Smart TVs use Tizen and WebOS, respectively), automobiles (for example, Tesla, Audi, Mercedes-Benz, Hyundai, and Toyota all rely on Linux), digital video recorders, video game consoles, and smartwatches. The Falcon 9's and the Dragon 2's avionics use a customized version of Linux.
Linux is one of the most prominent examples of free and open-source software collaboration. The source code may be used, modified and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the GNU General Public License.
90% of all cloud infrastructure is powered by Linux including supercomputers and cloud providers. 74% of smartphones in the world are Linux-based.
KDE Plasma 5
KDE Plasma 5 is the fifth and current generation of the graphical workspaces environment created by KDE primarily for Linux systems. KDE Plasma 5 is the successor of KDE Plasma 4 and was first released on 15 July 2014. It includes a new default theme, known as "Breeze", as well as increased convergence across different devices. The graphical interface was fully migrated to QML, which uses OpenGL for hardware acceleration, which resulted in better performance and reduced power consumption.
FreeBSD
FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular open-source BSD operating system, accounting for more than three-quarters of all installed simply, permissively licensed BSD systems.
FreeBSD has similarities with Linux, with two major differences in scope and licensing. First, FreeBSD maintains a complete system, i.e. the project delivers a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties for system software. Second, FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux.
The FreeBSD project includes a security team overseeing all software shipped in the base distribution. A wide range of additional third-party applications may be installed using the pkg package management system or FreeBSD Ports, or by compiling source code.
Much of FreeBSD's codebase has become an integral part of other operating systems such as Darwin (the basis for macOS, iOS, iPadOS, watchOS, and tvOS), TrueNAS (an open-source NAS/SAN operating system), and the system software for the PlayStation 3 and PlayStation 4 game consoles.
Google ChromeOS
ChromeOS (formerly Chrome OS, sometimes styled as chromeOS) is a Gentoo Linux-based operating system designed by Google. It is derived from the free software ChromiumOS and uses the Google Chrome web browser as its principal user interface. However, ChromeOS is proprietary software.
Google announced the project in July 2009, conceiving it as an operating system in which both applications and user data reside in the cloud: hence ChromeOS primarily runs web applications. Source code and a public demo came that November. The first ChromeOS laptop, known as a Chromebook, arrived in May 2011. Initial Chromebook shipments from Samsung and Acer occurred in July 2011.
ChromeOS has an integrated media player and file manager. It supports Chrome Apps, which resemble native applications, as well as remote access to the desktop. Reception was initially skeptical, with some observers arguing that a browser running on any operating system was functionally equivalent. As more ChromeOS machines have entered the market, the operating system is now seldom evaluated apart from the hardware that runs it.
Android applications started to become available for the operating system in 2014, and in 2016, access to Android apps in Google Play's entirety was introduced on supported ChromeOS devices. Support for a Linux terminal and applications, known as Project Crostini, was released to the stable channel in ChromeOS 69. This was made possible via a lightweight Linux kernel that runs containers inside a virtual machine.
ChromeOS is only available pre-installed on hardware from Google manufacturing partners, but there are unofficial methods that allow it to be installed in other equipment. Its open-source upstream, ChromiumOS, can be compiled from downloaded source code. Early on, Google provided design goals for ChromeOS, but has not otherwise released a technical description.
See also
Comparison of operating systems
Hypervisor
Interruptible operating system
List of operating systems
List of pioneers in computer science
Live CD
Glossary of operating systems terms
Microcontroller
Mobile device
Mobile operating system
Network operating system
Object-oriented operating system
Operating System Projects
System Commander
System image
Timeline of operating systems
Usage share of operating systems
Notes
References
Operating systems
Operating systems | Comparison of user features of operating systems | [
"Technology"
] | 5,740 | [
"Software comparisons",
"Computing comparisons"
] |
67,096,543 | https://en.wikipedia.org/wiki/S%C3%B6derala%20vane | The Söderala vane () is a weather vane dating from the Viking Age, richly ornamented and made of gilt bronze. It derives its name from in Söderala, Sweden, where it was used as a weather vane during the 18th century. It was most probably originally used as a vane on a Viking ship, and shows signs of wear. On stylistic grounds, it has been dated to 1050. It is today part of the collections of the Swedish History Museum. A copy of the vane is in Söderala.
History
In 1916, bought the vane from a farmer. At the time it was attached to an iron rod from the 17th century, and the small figure of an animal attached to the top of the vane was kept separately. The farmer who sold the vane to the museum also had a receipt from the late 18th century, showing that the vane had at that time been bought from where it had been used as a weather vane. The farmer was paid 50 Swedish crowns for the vane, which was subsequently sold to the Swedish History Museum in Stockholm, where it has remained part of the collections of the museum since. A copy is in Söderala. The weather vane is older than the church, which is the earliest known location of the vane. On stylistic grounds it has been dated to 1050, and scholars believe it was originally made to be used as a weather vane on a Viking ship. Comparisons with other Viking-age vanes and analysis of mentions of such vanes in the Icelandic sagas indicate that a vane of this size and splendour may have been made for a large ship like a longship.
Description
The Söderala vane consists of a triangular plate, made of gilt bronze and reinforced by smaller bronze plates and rivets in some places. A small sculpture of an animal, kept separately from the vane when it was bought by the museum, was originally attached to the top end of the bronze plate. The curved edge of the plate is pierced by several small holes, in which some kind of loosely hanging decorations may once have been attached. The plate itself is decorated with depictions of three beasts, interlaced with each other and with other purely decorative elements such as spirals, in a style closely related to that of Swedish burial monuments from the middle of the 11th century. The main decorative element is a depiction of a Norse dragon with wings, its forelegs and neck stretched somewhat like a horse about to rise. Its back is comparatively small. The dragon is very similar to a dragon depicted on a tombstone from the mid-11th century from Sundby Church in Södermanland, Sweden. Another creature lies coiled around the forelegs of the dragon, while the third, legless, is wrapped around the body of the dragon.
The vane has traces of continuous use as a weather vane, presumably on a ship, and had been repaired before it was converted for use as a church weather vane. Apart from wear, it has also been somewhat buckled as a result of considerable violence, possibly by being hit by projectiles during some battle.
It is not known where the vane was made. It is comparable with other Viking art objects from the same time from Sweden, but there are also details in the vane which show similarities with insular art, particularly Irish art. For instance, the wing and head of the dragon are comparable with similar ornamentation known from the British Isles, and the animal crowning the vane is similar to one depicted on an Irish crosier. It has therefore been speculated that the vane could have been made in present-day Sweden but also that it may have been made by Norse settlers on the British Isles.
References
Sources cited
External links
Viking art
Viking ships
Meteorological instrumentation and equipment
11th-century sculptures
Bronze sculptures in Sweden
Söderhamn Municipality
Collection of the Swedish History Museum | Söderala vane | [
"Technology",
"Engineering"
] | 779 | [
"Meteorological instrumentation and equipment",
"Measuring instruments"
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67,097,332 | https://en.wikipedia.org/wiki/Ajamxanthone | Ajamxanthone is a chemical compound which is produced by the fungus Aspergillus stellatus. Ajamxanthone forms yellow needles. Its synonyms are (+)-ajamxanthone and CTK8I3902.
References
Further reading
Mycotoxins
Xanthones | Ajamxanthone | [
"Chemistry"
] | 66 | [] |
67,097,838 | https://en.wikipedia.org/wiki/Rc-o319 | Rc-o319 is a bat-derived strain of severe acute respiratory syndrome–related coronavirus collected in little Japanese horseshoe bats (Rhinolophus cornutus) from sites in Iwate, Japan. Its has 81% similarity to SARS-CoV-2 and is the earliest strain branch of the SARS-CoV-2 related coronavirus.
References
SARS-CoV-2
Bat virome
Coronaviridae
Animal virology
Sarbecovirus
Zoonoses | Rc-o319 | [
"Biology"
] | 102 | [
"Virus stubs",
"Viruses"
] |
67,098,893 | https://en.wikipedia.org/wiki/Terrein | Terrein is a fungal metabolite of Aspergillus species. Terrein forms pale yellow crystal needles. Terrein has a strong cytotoxic activity against cells with colorectal carcinoma. The strain S020 from the fungus Aspergillus terreus has the highest rate in producing terrein.
References
Mycotoxins
Cyclopentenes | Terrein | [
"Chemistry"
] | 79 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
67,099,434 | https://en.wikipedia.org/wiki/Net%20Neutrality%20II | "Net Neutrality II" is the second segment of the HBO news satire television series Last Week Tonight with John Oliver devoted to net neutrality in the United States. It aired on May 7, 2017, for 19 minutes, as part of the eleventh episode of the fourth season, and the 100th episode overall.
During this segment, comedian John Oliver discusses the threat to net neutrality. Under the previous administration of President Barack Obama, the Federal Communications Commission (FCC) was considering two options for net neutrality in early 2014, which Oliver covered in a previous segment entitled "Net Neutrality". The FCC proposed permitting fast and slow broadband lanes, which would compromise net neutrality, but was also considering reclassifying broadband as a telecommunication service, which would preserve net neutrality. After a surge of comments supporting net neutrality that were inspired by Oliver's episode, the FCC voted to reclassify broadband as a utility in 2015.
The second episode dealt with a resurgence of the same problem, except under the administration of Donald Trump. The FCC was proposing to eliminate the 2015 rules that classified broadband as a utility, thereby allowing the implementation of slow and fast lanes. Despite another surge of comments following the second episode, the FCC proceeded with its plans to eliminate the 2015 regulations.
Plot
Oliver recaps his previous "Net Neutrality" episode and its aftermath. Afterward, Oliver describes the reason for his second episode: the Trump administration is rolling back Obama-era regulations, including Wheeler's net-neutrality rules. The comedian says, "I genuinely would not be surprised if one night Trump went on TV just to tell us that he personally killed every [Thanksgiving] turkey Obama ever pardoned".
Oliver shows a clip of YouTube personality Tay Zonday, who summarizes the concept of net neutrality. Zonday says that under net neutrality laws, ISPs have to treat all web traffic the same, and as an example, he says that an ISP cannot favor one search engine by slowing down traffic that uses other search engines. After the clip ends, Oliver paraphrases what Zonday just said: that under the concept of net neutrality, ISPs cannot impact or restrict people's online actions, and big companies cannot prevent competition from small companies. Oliver says that in the case of the latter, "Ancestry.com could easily crush my new site JustTellMeIfImRelatedToANazi.com. It's like ancestry.com except you get to skip all the bullshit." He then notes that major ISPs like Charter, Cox, and Comcast have all published statements that endorsed "a free and open internet", and that Verizon even made a video explaining that the change would "put the open Internet rules in an enforceable way on a different legal footing".
The comedian next explains Titles I and II of the Communications Act of 1934; the ruling provided by Comcast v. FCC; and Pai's appointment by President Trump. Oliver says that based on this context, Verizon's bid for a "different legal footing" was akin to "O. J. Simpson asking why you won't let him hold any of your samurai swords". He continues that the new FCC chairman's promise that the current rules' "days were numbered" and his vow to "take a weed whacker" to the current rules was like "serial killer talk". Pai's easygoing attitude, casual quotations of The Big Lebowski on his Twitter account, and affinity for his large Reese's-branded coffee mug made him personable, and according to Oliver, even more dangerous. Oliver says that Pai is a former lawyer for Verizon who has said that "we were not living in some digital dystopia before the partisan imposition of a massive plan hatched in Washington saved all of us", to which the comedian adds, "Except for Pizza Rat".
Oliver then takes a serious tone, saying that reclassification of ISPs was the only way to regulate them, and points out that Pai had erroneously said that there is no evidence of throttling by cable companies. Oliver refutes Pai's statement with a Bloomberg News article about how Verizon, AT&T, and T-Mobile had blocked their respective subscribers from accessing Google Wallet on their phones because it competed with their Isis Mobile Wallet service.
The comedian says that Pai has also proposed "laughably lacking" alternatives to net neutrality. One alternative stipulated that ISPs simply include a voluntary statement in their terms of service indicating that they would not throttle or block content, which Oliver says would "make net neutrality as binding as a proposal on The Bachelor". Pai's other rationales for reclassifying ISPs was that the new rules already resulted in decreased investment in broadband networks. Brian Schatz, a Democratic U.S. Senator representing Hawaii and the ranking member of the Senate Commerce Subcommittee on Communications, Technology, Innovation, and the Internet, said that Pai's claim of decreased investment was untrue. Oliver then quotes a 2014 phone call from Francis J. Shammo, the chief financial officer of Verizon, in which the latter says that the new net-neutrality rules did not affect Verizon's business. Oliver says, "that doesn't really sound like net neutrality was jeopardizing investment at all".
The ISPs' position on the net neutrality issue is that protections could be retained by an Act of Congress, but Oliver says that he does not trust Congress to go through. He also expresses distrust of President Trump, who had claimed that Obama's net-neutrality protections would "target conservative media", when in fact, that could only be achieved by the opposite scenario: a lack of net-neutrality protections. At the end of the segment, Oliver urges viewers to go to GoFCCYourself.com, a website redirecting to the specific FCC proposal. He says, "Every Internet group needs to come together like you successfully did three years ago … gamers; YouTube celebrities; Instagram models; Tom from MySpace, if you're still alive. We need all of you. You cannot say you are too busy when 540,000 of you commented on Beyonce's pregnancy announcement."
Web exclusive
In a segment posted only on YouTube the following week, Oliver talks about an update at the FCC. He describes how gofccyourself.com started trending on Twitter after the Net Neutrality II segment aired. Ultimately, the FCC website got 1.6 million extra comments as a result of the segment. Oliver shows a video of a news anchor describing this fact while using an image of Stephen Colbert, another comedian.
Oliver then reads off a comment from a person claiming to be from the International Space Station who complained about his porn website access being interrupted, to which he responds, "There is no one up there who has any use for porn, and I'll tell you why: they are way too busy space fucking". He also noted that several comments were using fake names like Homer Simpson, Barack Obama, and Michael Jackson, then said that "Michael Jackson" is a very common name, although one commenter writing under that name had listed an address of "420 Buthole st"—a reference to cannabis culture and posteriors. Oliver describes that some media had doubts about this net-neutrality drive, with one news anchor alleging that there were 128,000 spambot comments with fake names. He then says that some of the comments were racist, saying, "Let me just say, if any of those came from anyone who watches this show, stop it! Writing racist things on the Internet is not how you win the net neutrality debate, it's how you win the presidency." The comedian concludes by calling on viewers to refrain from adding any more comments, since the FCC stopped taking any comments a week before their May 18 vote on the issue.
Effects and reception
Oliver's segment was thought to have caused viewers to submit an extra 150,000 comments on the net neutrality proposal. As with the previous "Net Neutrality" segment, the FCC site was thought to have crashed temporarily as a result of the surge in commenting. However, the FCC later stated that the site was unavailable due to distributed denial-of-service (DDoS) attacks that were unrelated to the Oliver segments. HBO also denied having initiated the DDoS attacks. Engadget noted that apart from the specific page about the net-neutrality proposal, the rest of the FCC site was working at normal speeds. Several Congressional Democrats doubted that the cause of the FCC website's outage was a DDoS attack, and they called on the FCC to investigate the issue. BuzzFeed journalist Kevin Collier filed a lawsuit against the FCC after it refused to publish data related to the outage under the Freedom of Information Act.
In response to the segment, Ajit Pai made a video in which he read and responded to mean tweets about himself in the style of a Jimmy Kimmel Live! "Mean Tweets" segment. Pai read several tweets that mentioned several things that John Oliver had talked about in "Net Neutrality II", such as The Big Lebowski quotes and the Reese's mug, but he did not read any tweets referring to net neutrality itself. Gizmodo criticized Pai's video, saying that he refused to debate Oliver's points and instead "addresses a bunch of Twitter eggs", anonymous user profiles, "with the implication that anyone who opposes his cash grab for corporations is a moron".
Commenting period closes and FCC votes
As a result of the surge in comments, the public commenting period was extended by two weeks to August 30. A poll in mid-August found that 60% of Americans supported the rules while 17% opposed them. The ratio of support was consistent for voters from both the Democratic and Republican parties.
By the time the commenting period closed, the FCC had received 22 million comments on the issue, which was the highest number of comments for any FCC proposal to date. However, this included over 1 million comments from a spambot, most of which were made in support of the proposal to repeal net neutrality. One estimate placed the total number of fake comments in excess of 7 million, using variations from seven email templates. The fake emails used duplicate and temporary email addresses, submitted under names such as "The Internet", and at one point, 500,000 comments were sent in the span of a single second. Because the legitimacy of so many of the comments was questioned, the FCC considered disregarding every comment. Following this revelation, Pai refused to investigate the fake comments, so New York Attorney General Eric Schneiderman set up his own webpage to help the public determine whether their names and information were used in any of the fake comments.
Despite the 22 million comments, the FCC announced plans to repeal net neutrality anyway in November 2017. After this announcement, several news media made references to the John Oliver segments about the issue. On December 14, 2017, the FCC voted in favor of repealing these policies.
References
External links
2017 American television episodes
Last Week Tonight with John Oliver segments
Net neutrality | Net Neutrality II | [
"Engineering"
] | 2,287 | [
"Net neutrality",
"Computer networks engineering"
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67,099,557 | https://en.wikipedia.org/wiki/Moon%20J.%20Park | Moon Jeong Park (박문정) is a Korean chemical engineer who is a Professor of Chemistry at Pohang University of Science and Technology. She is interested in polymers for energy storage and transport. She studies the transport in charge-containing polymeric materials. She is the second non-American recipient to be awarded the American Physical Society John D. Dillion Medal and the 2016 Hanwha Total IUPAC Young Scientist Award.
Early Career and education
Park was born in 1977 in South Korea. Park completed her Ph.D. the Seoul National University in 2006. She was advised by Kookheon Char. In 2009, she was a postdoctoral research fellow with Nitash P. Balsara at University of California, Berkeley.
Research and career
Park joined as assistant professor to the department of chemistry at Pohang University of Science and Technology in 2009. She was promoted to associate professor in 2013. Her research interests includes understanding the thermodynamics and transport in charge-containing polymeric materials. Park specifically focuses on developing polymeric materials that are more efficient, predictable, and sustainable for energy storage and transport. She has developed a lithium sulfur battery technology to increased charging speeds and have longer battery life. Her main contributions have been in ionic-liquid containing polymers, design of self-assembled polymer electrolytes, organic-organics nano-hybrids for enhanced ion/charge transport, and chemical sensors based on ionic polymers. She also works on electric responsive actuators to create artificial muscles.
Park is an associate editor of Macromolecules. She also on the editorial board of Journal of Polymer Science: Polymer Physics and Journal of Applied Polymer Science.
Awards and honors
2021 Fellow of the American Physical Society, "for creative and insightful experiments to elucidate the roles of molecular architecture and self-assembled nanostructure on the electrical, ion transport, and mechanical properties of charged polymers"
2017 American Physical Society John H. Dillion Medal
2016 20th Young Scientist Award, Ministry of Science and Technology (South Korea). ICT and Future Planning of Korea
2016 Hanwha Total-IUPAC Young Polymer Scientist Award
2015 Woman Scientist/Engineer of the Year Award
2011 Asia Excellence Award Young Scientists, Society of Polymer Science Japan
2011 Chong-Am Science Fellowship, POSCO (formerly Pohang Iron and Steel Company), TJ Park Foundation
2004 Best Paper Award, IUPAC World Polymer Congress
References
1977 births
Living people
Materials scientists and engineers
21st-century South Korean scientists
Academic staff of Pohang University of Science and Technology
Seoul National University alumni
Fellows of the American Physical Society | Moon J. Park | [
"Materials_science",
"Engineering"
] | 528 | [
"Materials scientists and engineers",
"Materials science"
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67,099,709 | https://en.wikipedia.org/wiki/Kepler-174 | Kepler-174 is a K-type main-sequence star located in the Milky Way galaxy at a distance of about away from the Sun. It is located inside the boundaries of the Lyra constellation, but it is too dim to be visible to the unaided eye and is not part of the main outline.
Planetary system
Kepler-174 has three confirmed super-Earth planets orbiting it, Kepler-174b, Kepler-174c and Kepler-174d, discovered by the Kepler space telescope using the transit method. The discovery of all three planets was announced in 2014 by a team led by Jason F. Rowe, as part of a study validating hundreds of Kepler planets. Kepler-174d is notable as it is within the star's habitable zone, meaning it is potentially habitable.
In popular culture
The planet Kepler-174d is mentioned in the Star Trek: Discovery episode, Terra Firma, Part 1. in which it is inhabited and is referred to as "quite beautiful".
References
Lyra
K-type main-sequence stars
Planetary systems with three confirmed planets
0518
J19094540+4349555
158434144 | Kepler-174 | [
"Astronomy"
] | 236 | [
"Lyra",
"Constellations"
] |
67,100,427 | https://en.wikipedia.org/wiki/Biology%20of%20Sex%20Differences | Biology of Sex Differences is an online-only open access scientific journal covering the biological basis of sex differences in humans and other animals. It was established in 2010 and is published by BioMed Central on behalf of the Organization for the Study of Sex Differences, of which it is the official journal, as well as the Society for Women's Health Research. The editor-in-chief is Jill Becker (University of Michigan). According to the Journal Citation Reports, the journal has a 2021 impact factor of 8.811.
References
External links
Sexual dimorphism
BioMed Central academic journals
Academic journals established in 2010
English-language journals
Biology journals
Sexology journals | Biology of Sex Differences | [
"Physics",
"Biology"
] | 134 | [
"Sex",
"Sexual dimorphism",
"Symmetry",
"Asymmetry"
] |
67,100,525 | https://en.wikipedia.org/wiki/Headless%20commerce | Headless commerce is an e-commerce architecture where the front-end (head) is decoupled from the back-end commerce functionality and can thus be updated or edited without interfering with the back-end, similar to a headless content management system (CMS). The term was coined by Dirk Hoerig, co-founder of Commercetools, in 2013.
History
Headless commerce was arguably born out of a 2013 Forrester Research report that bemoaned e-commerce vendors falling behind user experience trends and recommended “loosely” coupling the back- and front-ends of e-commerce stores.
Architecture
Headless commerce architecture passes requests between a platform's presentation and application layers. The presentation layer is connected with the e-commerce functionality via REST APIs, or application programming interfaces, which define interactions between multiple software intermediaries. This allows businesses to change customer-facing experiences without disrupting backend functionality and to update, edit or change products and distribute via API to multiple front-ends. REST APIs are the backbone of this architecture.
Coupled e-commerce vs headless e-commerce
Headless commerce is distinct from coupled, traditional or “monolithic” e-commerce in that the latter relies on a front-end and back-end that function together and the former comprises solely a back-end which communicates with front-ends via APIs.
Headless commerce platforms offer advantages over traditional e-commerce platforms in that changes to data and functionality only need to be made in a single back-end, with all front-ends then having immediate access to those changes. Likewise, each front-end can then be changed and deployed without impacting the back-end. Another difference is that many traditional e-commerce platforms come with predefined front-end templates or customization, whereas headless commerce can power any front-end via APIs.
Headless commerce platforms require more work and customization than traditional platforms and are often not suitable for smaller businesses. Such platforms lack predesigned templates and do not provide all-in-one solutions. Headless commerce platforms also require developers to build or buy a separate front-end.
Headless commerce may be preferred from a quality assurance perspective, as traditional e-commerce platforms face a higher risk of making changes that could disrupt operations, since the front end and back end are coupled. Because headless commerce communicates with the front-end via APIs and there is no code intertwined with the backend database that stores content, frontend developers can adapt endpoint layout as needed with no disruptions to the customer experience.
Flexibility
The front-ends and back-ends of a headless system are decoupled, making it possible to change the content layer without disrupting business. This creates flexibility to allow the front- and back-ends to work independently and create new user experiences without compromising old ones. There is also no confining code that restricts delivery to internet of things devices, applications, web browsers or other end points.
Speed
The decoupled architecture of headless commerce enables developers to make quick changes, such as implementing new functionalities and integrations without disrupting the back end.
Personalization
Headless commerce allows for the creation of customized designs and layouts for different endpoints, since front-end design can be changed without impacting the back-end.
Unified user experience
Headless commerce allows a business to control all customer touchpoints at once. This creates a consistent customer experience across different front-ends that enable customers to complete a purchase at any touch point.
Headless commerce providers
Dynamics 365 Commerce
Brink Commerce
Swell
Shogun
Commerce.js
Oracle CX Commerce
Shopify
Magento
Commercetools
Crystallize
Fabric
Salesforce Commerce Cloud
Nacelle
BigCommerce
Slatwall Commerce
Bagisto
Slixta
bl!nk
Pcommerce
VetrinaLive
ElasticPath
SAP Commerce Cloud
Rierino
TheShop Management
References
See also
Headless content management system
Shopping cart software
Content management systems
E-commerce
E-commerce software | Headless commerce | [
"Technology"
] | 825 | [
"Information technology",
"E-commerce"
] |
67,101,100 | https://en.wikipedia.org/wiki/Indaziflam | Indaziflam is a preemergent herbicide especially for grass control in tree and bush crops.
History
In 1991, the Japanese company Idemitsu Kosan filed a patent to 2-amino 6-fluoroalkyl triazine derivatives as herbicides. One of these compounds was subsequently given the ISO common name triaziflam but had limited success as a commercial herbicide. Bayer scientists subsequently investigated this area of chemistry and identified indaziflam as having superior properties, which they patented and developed under the code number BCS-AA10717. The compound was first registered for use in the USA in 2010.
Mechanism of action
Indaziflam is an inhibitor of cellulose biosynthesis. This mechanism of action was theorized to be responsible for indaziflam's effect in 2009 and proven in 2014. The cellulose biosynthesis inhibitors (CBIs) are identified as Class 29 by the Weed Science Society of America/Herbicide Resistance Action Committee.
Resistance
there are no resistant populations known and none for the broader CBI class (discounting quinclorac).
Brand names
Indaziflam composes all or part of the a.i. of several herbicides from Bayer Environmental Science (now owned by Cinven, aka Envu, per Bayer's and Envu's websites),
including Rejuvra, the Esplanade line (sometimes mixed with diquat dibromide and glyphosate isopropylamine), Marengo, Specticle, and Bayer CropScience (the inventor of the ingredient), like Alion.
Uses
Indaziflam is approved in the United States for hops, Rubus spp., Coffea spp., bushberries, tropical crops, drupes/stone fruit, and tree nuts. It is used as a preemergent.
References
Herbicides
Triazines
Organofluorides
Amines | Indaziflam | [
"Chemistry",
"Biology"
] | 406 | [
"Herbicides",
"Functional groups",
"Amines",
"Biocides",
"Bases (chemistry)"
] |
67,101,254 | https://en.wikipedia.org/wiki/Photoautotroph | Photoautotrophs are organisms that can utilize light energy from sunlight and elements (such as carbon) from inorganic compounds to produce organic materials needed to sustain their own metabolism (i.e. autotrophy). Such biological activities are known as photosynthesis, and examples of such organisms include plants, algae and cyanobacteria.
Eukaryotic photoautotrophs absorb photonic energy through the photopigment chlorophyll (a porphyrin derivative) in their endosymbiont chloroplasts, while prokaryotic photoautotrophs use chlorophylls and bacteriochlorophylls present in free-floating cytoplasmic thylakoids or, in rare cases, membrane-bound retinal derivatives such as bacteriorhodopsin. The vast majority of known photoautotrophs perform photosynthesis that produce oxygen as a byproduct, while a small minority (such as haloarchaea and sulfur-reducing bacteria) perform anoxygenic photosynthesis.
Origin and the Great Oxidation Event
Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. Oxygenic photosynthesis was the primary source of free oxygen and led to the Great Oxidation Event roughly 2.4 to 2.1 billion years ago during the Neoarchean-Paleoproterozoic boundary. Although the end of the Great Oxidation Event was marked by a significant decrease in gross primary productivity that eclipsed extinction events, the development of aerobic respiration enabled more energetic metabolism of organic molecules, leading to symbiogenesis and the evolution of eukaryotes, and allowing the diversification of complex life on Earth.
Prokaryotic photoautotrophs
Prokaryotic photoautotrophs include Cyanobacteria, Pseudomonadota, Chloroflexota, Acidobacteriota, Chlorobiota, Bacillota, Gemmatimonadota, and Eremiobacterota.
Cyanobacteria is the only prokaryotic group that performs oxygenic photosynthesis. Anoxygenic photosynthetic bacteria use PSI- and PSII-like photosystems, which are pigment protein complexes for capturing light. Both of these photosystems use bacteriochlorophyll. There are multiple hypotheses for how oxygenic photosynthesis evolved. The loss hypothesis states that PSI and PSII were present in anoxygenic ancestor cyanobacteria from which the different branches of anoxygenic bacteria evolved. The fusion hypothesis states that the photosystems merged later through horizontal gene transfer. The most recent hypothesis suggests that PSI and PSII diverged from an unknown common ancestor with a protein complex that was coded by one gene. These photosystems then specialized into the ones that are found today.
Eukaryotic photoautotrophs
Eukaryotic photoautotrophs include red algae, haptophytes, stramenopiles, cryptophytes, chlorophytes, and land plants. These organisms perform photosynthesis through organelles called chloroplasts and are believed to have originated about 2 billion years ago. Comparing the genes of chloroplast and cyanobacteria strongly suggests that chloroplasts evolved as a result of endosymbiosis with cyanobacteria that gradually lost the genes required to be free-living. However, it is difficult to determine whether all chloroplasts originated from a single, primary endosymbiotic event, or multiple independent events. Some brachiopods (Gigantoproductus) and bivalves (Tridacna) also evolved photoautotrophy.
References
Trophic ecology
Biology terminology
Photosynthesis | Photoautotroph | [
"Chemistry",
"Biology"
] | 829 | [
"Biochemistry",
"Photosynthesis",
"nan"
] |
67,101,774 | https://en.wikipedia.org/wiki/Asus%20Transformer%20Pad%20TF103C | The Asus Transformer Pad TF103C is a 2-in-1 detachable tablet from the Asus Transformer Pad series.
Features
It has a 1.86 GHz quad-core Intel Atom Bay Trail processor, 1GB of RAM, 16GB of internal storage, and a microSD card slot, which accepts cards of capacities up to 64GB. It has a 10.1 inch display of 1280x800.
Docking keyboard
It includes a keyboard dock.
Software
It includes Asus Zen interface.
It has Android 4 by default but can optionally be upgraded to Android 5.
In January 2022, mainline Linux support was added for the TF103C.
See also
Asus Transformer Pad TF701T
Asus Transformer Pad TF300T
References
2-in-1 PCs
Android (operating system) devices
Asus products | Asus Transformer Pad TF103C | [
"Technology"
] | 181 | [
"Crossover devices",
"2-in-1 PCs"
] |
67,102,862 | https://en.wikipedia.org/wiki/List%20of%20HyperCard%20viruses | Soon after the release of HyperCard in 1987, computer viruses appeared that targeted the application. The viruses were written in the HyperTalk programming language and typically spread by infecting the Home stack and then infecting other stacks from there.
List of viruses
References
Classic Mac OS viruses
Computing-related lists | List of HyperCard viruses | [
"Technology"
] | 62 | [
"Computing-related lists"
] |
67,102,966 | https://en.wikipedia.org/wiki/Proprietary%20drug | Proprietary drug are chemicals used for medicinal purposes which are formulated or manufactured under a name protected from competition through trademark or patent. The invented drug is usually still considered proprietary even if the patent expired. When a patent expires, generic drugs may be developed and released legally. Some international and national governmental organizations have set up laws to enforce intellectual property to protect proprietary drugs, but some also highlight the importance of public health disregarding legal regulations. Proprietary drugs affect the world in various aspects including medicine, public health and economy.
Not all proprietary drugs have their generic replacements available. Biologics are often produced by in vivo preparation and direct extraction of substances from living organisms. Pharma is not extensively involved in searching for ready-to-sell generic biologics due to the complexity of manufacture and hurdles in extraction processes. Besides vaccines, these endogenous origin chemicals are prescribed to patients with severe conditions, such as complications including asthma, rheumatoid arthritis, or cancer. Patients taking a particular brand of biologics are unable to interchange between one and another to prevent underlying exposure to more side effects and/or suboptimal treatment. It is believed that generic biopharmaceutical products will not be released in the near future until all technical difficulties are overcome.
The table below shows some examples of pharma and their past/current proprietary medications:
Terminology
Brand name drugs
Broadly defined as drugs that are marketed under trade names and have patents, which can be a synonym of proprietary drugs in daily use. Strictly speaking, every drug with a trade name is a brand name drug, such as Panadol, a GSK branded paracetamol.
Generic drugs
Generic drugs are drugs that have the same active ingredient with a patent-expired drug, and are virtually bio-equivalent. The official names are often used to market these drugs, which are called unbranded generic drug, such as Panamax, a generic form of paracetamol.
Off-patent drugs
A term specifically used to describe past proprietary drugs by referring to their off-patent status.
Regulations
To support scientific investigation and protect intellectual properties, patents are granted to companies and individuals who invented the drug. Most entities in the world have established corresponding agendas legally. Global and regional governmental organizations have various extents of advancements and approaches in their intellectual property rights protection laws. Below are some examples for comparison:
World Trade Organization (WTO)
TRIPS Agreement
The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS Agreement) set up in 1994 suggested a standard on Intellectual Property Rights, which proprietary drug, a type of pharmaceutical and scientific inventions, is covered in this agreement. Basic principles such as the minimal duration of patent and part of the exclusive rights of patent owners are included by WTO member states in their respective national regulations. By 5 years and 10 years after the effectiveness of TRIPS Agreement, developed countries and developing countries were required to comply with it.
Doha Declaration
Trying to alleviate worldwide divide in accessibility of medical resources, members from the WTO endorsed the Doha Declaration on the TRIPS Agreement and Public Health in 2001. The basics of this Declaration is that "the TRIPS Agreement does not and should not prevent Members from taking measures to protect public health". It legalized the participating members to ignore the restriction from the patent of the proprietary medicine when they are controlling a significant public health crisis, namely human immunodeficiency virus (HIV), malaria and tuberculosis. Thus, affordable generic medicine can be provided for the populations in the developing countries in emergency situations.
United States
In the United States, proprietary drugs are associated with two status: patent and exclusivity. Patent is managed by the United States Patent and Trademark Office, granting inventors of new drugs rights for 20 years. It is open to all drugs, regardless of its research or commercialization status. To enjoy the benefits brought by patenting, pharmaceutical companies are obliged to disclose all research data on that drug to the public for further progression. Exclusivity, given by the U.S. Food and Drug Association (FDA), means a period of time in which no other competitor drugs can be approved. Commercialized and clinically used drugs are the targets of exclusivity. The length of exclusivity depends on the nature of application, and ranges from one to seven years. Practically exclusivity is granted for proprietary drugs that have been granted with patents, but it is not mandatory. Legalwise, generic counterparts have to wait for at least 2 decades for patent expiration to sell a copy . This system is said to aim for a balance between gaining public access to generic drugs and encouraging drug research and development.
Litigation
Despite the US having a legal system regarding to drug patenting, litigation have taken place. In the past, it is common for drug manufacturers challenging the validity of patents. In 2018, Mylan attempted to revoke the patent of Symbicort owned by AstraZeneca through the court. Now pharma suing on deliberately infringing generic drugs has become more prominent. AstraZeneca then took follow-up actions against Mylan for premature submission of Abbreviated New Drug Application (ANDA) for generic Symbicort and won the lawsuit. The introduction of biopharmaceuticals and the subsequent establishment of new drug laws may also bring more litigation.
India
According to the Patent Law in India, drug can apply for a patent since 2005. Registering a drug for patents in India is more limiting than developed countries. India was removed from the least developed member states list of the WTO and is therefore no longer eligible for the waiver, it has modified its patent law to satisfy TRIPS Agreement with its intellectual property rights legal system. An Indian patent lasts for 20 years. To ensure the interest of public, a compulsory license can be issued by the government if a pharma is suspected for violating the public health principles.
Litigation
Introducing new drug patenting regulations after 35 years could possibly lead to today's disputes, such as the Novartis v. Union of India incident. Generic Gleevec, a formulation that can substitute Glivec, were distributed in the local market since 1993. Novartis had filed a patent for Glivec in 1997. An exclusive marketing right was also granted for Novartis in 2003 and the application were approved in 2005 . In 2013, the Supreme Court of India upheld the rejection of the patent application of Glivec by Novartis, ending the 10-years battle between the proprietary drug tycoon and the local patent law. Since 1993, Novartis has started to register patent for Glivec and its active ingredients worldwide without defeats. However, the Supreme Court of India rejected the patent registration of Glivec on 2006 according to the interpretations on the patent law and TRIPS agreement by the Court. By then, the local generic drugs in India are protected. This incident is referred as a challenge to the intellectual property laws.
Patent cliff
Patent cliff refers to a dramatic dip in the revenue of a merchandise upon patent expiry. It is a prominent phenomenon in the proprietary drug industry due to the vast gap of prices between the proprietary drug and the generic drug. Since 2010, numerous pharmaceutical board busters have started to become off-patent. As seen in the figure below, the top five off-patent proprietary drug before 2017 have a combined lifetime sale of around US$588.4 Billion, which is enormous enough to surpass the bottom 5% countries' GDP in 2020.
Figure 1: Five best-selling proprietary drug which lost their patents before 2017
Proprietary drug is a substantial business protected by its respective patent. They are usually sold at a higher price, to compensate for the clinical trial cost and sometimes for the manufacturing of new technology. For example, an widely used average proprietary drug is 18 times more expensive than a common generic drug. Lyrica, a recent off-patent painkiller for nervous systems, had a sale of 5B USD in 2019, out of the 51.8B USD annual sale of the corresponding company.
However, once the proprietary drug become off-patent, there will soon be immense competition from the generic drugs produced by their business rivals. As cheaper pharmaceutical alternatives are launched, the surge in supply disrupts the market supply-and-demand status. The declining dependence on the original proprietary drug will cause its sales decreases. On top of that, the original company usually will have their prices tuned down for improving competitiveness. Resulting in a significant drop of revenue of the proprietary drug.
Below showed the graph which represented the yearly revenue of Lipitor, a proprietary drug which lost its patent on 2011. As it can be seen, a significant patent cliff happened from 2011 to 2012(58.8% drop in yearly revenue) and it is very possibly due to its newly off-patent status.
Figure 2: The yearly revenue of Lipitor by Pfizer (million US dollars) from 2004 to 2019
Benefits
Promoting influx of income to pharmaceutical research industry
Proprietary drug market is protected by its patent. As a result, its market exclusivity basis allows proprietary drugs to be highly profitable and commercially successful. Usually, pharmaceutical research is a lengthy, highly demanding, rarely successful, costly and risky investment. It is usually associated with a disinterested merchandise in the economic world. However, once a successful experimental drug candidate is registered as a proprietary drug product, the patent legally ensures a long-term dominance in the exclusive market which is free of imitative generic drug. Generating a stable and considerable net income to cover the cost.
The huge earning of the proprietary drug can circulate back to fund future medical research. Providing more resources and manpower to the research and development of another drug candidates. As well as attracting new investments to the pharmaceutical research industry due to its exclusive market potential. They encourage efforts on biopharmaceutical innovations and newborn medical breakthroughs.
Guiding future medical progresses by referencing of product knowledge
Being required for successful patent registration, detailed pharmaceutical formulations of the proprietary drug are disclosed on its patent registration application, which promote the spillover of research efforts among the medical world. In order to inspect the safety and efficacy of the proprietary drug candidate, pharmaceutical companies need to list all clinical trial data and formulation method as detailed as possible to prove the drug candidate's validity to the patent registration committee. Once the patent is rewarded, these data will later be published on medical literature and public domains as common knowledge.
Researchers can capitalise on the previous successes and establish their own project on top of the current statistics. These cooperatively help exploit more unknown drug candidates without repeating previous progresses. Speeding up future medical advancements.
Criticisms
Hindering of equitable access to medicine
According to World Health Organisation(WHO), equitable access to medicines refers to an affordable and reasonable ability for patients to get their required drug to achieve health. WHO member states shall fulfill their moral responsibility to improve the delivery of and access to the needed drugs.
However, the monopolisation of some expensive proprietary drug in the market is hindering poor patients' access to their best available medications. Leading to suboptimal treatments of diseases and lowering of health standard of these patients. This phenomenon is very prominent in the underdeveloped countries which usually have a large proportion of underprivileged citizens.
Some proprietary drugs(mainly speciality proprietary drug) are criticised for their price-gouging commercial tactics. To illustrate, the world's most expensive drug, Zolgensma, costs over US$2.1 million per year of treatment, which are generally considered as unaffordable. Since Zolgensma is the only approved drug for curing Spinal Muscular Atrophy in childhood, patients who cannot afford Zolgensma will be physically disabled for the rest of their lives. Creating inequity among patients with varying financial capacitances.
Abusing of patent extension system
According to the TRIPS Agreement, the term of patent of the proprietary drug usually can last for 20 years counting from the filing date. After that, approved generic drugs can enter the market legally with fair competition.
However, in order to achieve longer dominance in the market, pharmaceutical manufacturer (especially big pharma) may apply for patent extension or even new patent registration based on various reasons. Including modifying the formulations, dosage form or maneuvering legal system. To illustrate, AbbVie, a pharmaceutical tycoon, had attempted 247 proprietary drug patent extension applications for extending their exclusivity for 39 years in the USA on 2018 alone. Among them, 137 applications were successful in extending the patent.
The abusing of patent extension system leads to a much longer terms of patent than that stated in both local regulations and TRIPS Agreement. Providing a long period of competition-free market to their proprietary drug. It creates an unfair competition environment in the pharmaceutical market. Since the generic drug companies are excluded from that particular market, they cannot release new pharmaceutical products for public use on the same field. Resulting enduring monopolisation of proprietary drug market by the big pharma which are already stockpiling proprietary drug.
See also
Doha Declaration
Medicines Patent Pool
Generic drug
Generic brand
Intellectual property
Novartis v. Union of India & Others incident
Patent
Patent Cliff
Pharmaceutical Industry
Trademark
TRIPS agreement
References
Drugs | Proprietary drug | [
"Chemistry"
] | 2,692 | [
"Pharmacology",
"Chemicals in medicine",
"Drugs",
"Products of chemical industry"
] |
67,103,631 | https://en.wikipedia.org/wiki/Kamal%20Benslama | Kamal Benslama is a Moroccan-Swiss experimental particle physicist. He is a professor of physics at Drew University, a visiting experimental scientist at Fermilab, and a guest scientist at Brookhaven National Laboratory. He worked on the ATLAS experiment, at the Large Hadron Collider (LHC) at CERN in Switzerland. Currently, he is a member of the Mu2e experiment at Fermilab.
Biography
Originally from Morocco, Benslama studied physics at Geneva University. He obtained a bachelor and a master's degree in high-energy physics from Geneva University. In 1998, he completed a PhD at the department of High Energy Physics at the University of Lausanne.
After a short post-doc at the University of Lausanne, Benslama moved to North America in 1999. He first worked as a post-doc on the CLEO experiment at Cornell University in the US, and while at Cornell he collaborated with Syracuse University and the University of Illinois Urbana-Champaign. Then he became a research associate at the University of Montreal before becoming a post-doctoral research scientist at Columbia University in New York and associate scientist on the ATLAS experiment at Large Hadron Collider (LHC) at CERN. from 2006 to 2012, he was a professor of physics at the University of Regina in Canada. During this time, Benslama founded and led an international research group in experimental high-energy physics. He worked on the ATLAS experiment at CERN where he was a principal investigator and a team leader. He also was a member of the international ATLAS collaboration board and a member of the Liquid Argon representative board.
Benslama started his research activities at CERN in 1992, he first worked on ATLAS, then on NOMAD, (Neutrino Oscillation search with a MAgnetic Detector) which was designed to search for neutrino oscillation. His thesis was on the construction, installation and simulation of a preshower particle detector as well as on data analysis using data from the NOMAD experiment.
Benslama contributed to many aspects of the ATLAS experiment. He worked on a readout system for a silicon detector for the ATLAS experiment, then he worked on the Liquid Argon Calorimeter, the High Level Trigger and Data Quality and Monitoring. He also led several efforts on searches for physics beyond the standard model at the LHC, in particular searches for doubly charged higgs, extra-dimensions and leptoquarks. He was heavily involved in the exotics physics program at the LHC.
Before joining Drew University as a faculty, Benslama was a visiting professor at Loyola University Maryland and later he was a Senior Lecturer and Research Professor at Towson University
Private life
Kamal Benslama has three children and lives in New Jersey.
Selected work
Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
Prospects for the search for a doubly charged Higgs in the left–right symmetric model with ATLAS - G. Azuelos, K. Benslama, J. Ferland, 10 March 2005, J.Phys.G32:73-92,2006
Exploring Little Higgs Models with ATLAS at the LHC - Azuelos, G; Benslama, K. Benslama et al. - Eur. Phys. J., C 39 (2005) 13-24
Design and implementation of the Front End Board for the readout of the ATLAS liquid argon calorimeters - N.~J.~Buchanan et al. - JINST 3, P03004 (2008)
Search for pair production of first or second generation leptoquarks in proton-proton collisions at √s=7 TeV using the ATLAS detector at the LHC
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at sqrt(s)=7 TeV
Measurement of the W → ℓν and Z/γ* → ℓℓ production cross sections in proton-proton collisions at sqrt(s)=7TeV with the ATLAS detector
Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton–proton collision data
Measurements of charmless hadronic two-body B meson decays and the ratio B(B to DK)/B(B to DPi)
Liste de publications et citations
References
External links
FermiLab
The ATLAS Experiment
Large Hadron Collider at CERN
20th-century births
20th-century Swiss physicists
21st-century Swiss physicists
Moroccan physicists
Particle physicists
Living people
Experimental physicists
University of Lausanne alumni
Year of birth missing (living people)
University of Geneva alumni
People associated with CERN
Swiss people of Moroccan descent
Swiss expatriates in the United States
Cornell University staff
Columbia University staff
Academic staff of the University of Regina
Drew University faculty | Kamal Benslama | [
"Physics"
] | 989 | [
"Experimental physicists",
"Particle physicists",
"Particle physics",
"Experimental physics"
] |
57,567,075 | https://en.wikipedia.org/wiki/Prodiamine | Prodiamine is a preemergent herbicide of the dinitroaniline class. Prodiamine is used with crops such as soybeans, alfalfa, cotton, and ornamental crops. Prodiamine inhibits the formation of microtubules.
Prodiamine was developed by Sandoz AG and marketed beginning in 1987.
Prodiamine can be obtained starting from 2,4-dichlorobenzotrifluoride.
References
Herbicides
Trifluoromethyl compounds
Anilines
Nitrobenzene derivatives
Preemergent herbicides | Prodiamine | [
"Biology"
] | 119 | [
"Herbicides",
"Biocides"
] |
57,568,981 | https://en.wikipedia.org/wiki/Hiba%20Mohamed | Hiba Salah-Eldin Mohamed (, born 18 January 1968) is a Sudanese molecular biologist who works at the University of Khartoum. She won the 2007 Royal Society Pfizer Award.
Early life and education
Hiba studied zoology at the University of Khartoum, earning a Bachelors in 1993 and a Masters in 1998. She moved to the University of Cambridge Institute for Medical Research (CIMR) for her PhD in 2002. Her doctoral research, "The role of Host Genetics in Susceptibility to Kala-azar in The Sudan", was under the supervision of Jenefer Blackwell. She remained at the CIMR as a postdoctoral fellow.
Research
Hiba was awarded a Wellcome Trust Research Development Award, and moved back to the University of Khartoum to be a professor in the Department of Molecular Biology. Her research focuses on understanding the genetics of Visceral leishmaniasis.
She was awarded the 2007 Royal Society Pfizer Award for her research into the disease, which is transmitted by sandfly bites. There is no vaccine or effective treatment, and up to 350 million people are at risk worldwide. Hiba was part of the Royal Society Africa Week celebrations in 2008. In 2010, Hiba was appointed a Fellow of the Global Young Academy.
Selected publications
Blackwell, Jenefer M; Searle, Susan; Mohamed, Hiba; White, Jacqueline K (2003-01-22). Divalent cation transport and susceptibility to infectious and autoimmune disease: continuation of the Ity/Lsh/Bcg/Nramp1/Slc11a1 gene story. Immunology Letters. 85 (2): 197–203. doi:10.1016/S0165-2478(02)00231-6. ISSN 0165-2478.
Mohamed, Hiba Salah; Ibrahim, Muntaser Eltayeb; Miller, Elinor Nancy; White, Jacqueline Katie; Cordell, Heather Jane; Howson, Joanna McCammond McGill; Peacock, Christopher Sean; Khalil, Eltahir Awad Gasim; El Hassan, Ahmed Mohamed; Blackwell, Jenefer Mary (2004-01). SLC11A1 (formerly NRAMP1) and susceptibility to visceral leishmaniasis in The Sudan. European Journal of Human Genetics. 12 (1): 66–74. doi:10.1038/sj.ejhg.5201089. ISSN 1476-5438.
Blackwell, J. M.; Fakiola, M.; Ibrahim, M. E.; Jamieson, S. E.; Jeronimo, S. B.; Miller, E. N.; Mishra, A.; Mohamed, H. S.; Peacock, C. S.; Raju, M.; Sundar, S.; Wilson, M. E. (2009-05). Genetics and visceral leishmaniasis: of mice and man. Parasite Immunology. 31 (5): 254–266. doi:10.1111/j.1365-3024.2009.01102.x. PMC 3160815. PMID 19388946.
Mohamed, H. S.; Ibrahim, M. E.; Miller, E. N.; Peacock, C. S.; Khalil, E. a. G.; Cordell, H. J.; Howson, J. M. M.; El Hassan, A. M.; Bereir, R. E. H.; Blackwell, J. M. (2003-07). Genetic susceptibility to visceral leishmaniasis in The Sudan: linkage and association with IL4 and IFNGR1. Genes & Immunity. 4 (5): 351–355. doi:10.1038/sj.gene.6363977. ISSN 1476-5470
See also
Sultan Hassan
Nashwa Eassa
Layla Zakaria Abdel Rahman
References
External links
1968 births
Living people
Sudanese women academics
Molecular biologists
Sudanese scientists | Hiba Mohamed | [
"Chemistry"
] | 864 | [
"Molecular biologists",
"Biochemists",
"Molecular biology"
] |
57,569,150 | https://en.wikipedia.org/wiki/Lopharia%20cinerascens | Lopharia cinerascens is a species of crust fungus in the family Polyporaceae. It was first described by botanist Lewis David de Schweinitz in 1832 as Thelephora cinerascens. Gordon Herriot Cunningham transferred it to Lopharia in 1956. It is widely distributed in Africa, Asia, Australasia, and North America; it is less common in Europe and South America.
References
Fungi described in 1832
Fungi of Africa
Fungi of Asia
Fungi of Australia
Fungi of Europe
Fungi of New Zealand
Fungi of North America
Fungi of South America
Polyporaceae
Taxa named by Lewis David de Schweinitz
Fungus species | Lopharia cinerascens | [
"Biology"
] | 131 | [
"Fungi",
"Fungus species"
] |
57,569,173 | https://en.wikipedia.org/wiki/Kim%20Jelfs | Kim E. Jelfs is a computational chemist based at Imperial College London who was one of the recipients of the Harrison-Meldola Memorial Prizes in 2018. She develops software to predict the structures and properties of molecular systems for renewable energy.
Early life and education
Jelfs studied chemistry at University College London. For her final year project, Jelfs worked at the Royal Institution. She earned her PhD in 2010, working with Ben Slater on modelling the growth of zeolitic materials.
Research and career
After completing her PhD Jelfs joined the University of Barcelona, working with Stefan Bromley. She moved to the University of Liverpool, working as a postdoctoral researcher with Matthew Rosseinsky and Andrew Ian Cooper. At the University of Liverpool Jelfs characterised the structure of porous materials. She was funded by an Engineering and Physical Sciences Research Council Programme Grant.
In 2013 she joined Imperial College London as a Royal Society University Research Fellow. In 2015 she was awarded a European Research Council Starting Grant, which provides €1.5 million funding for five years of materials discovery. Her research will consider porous molecules, organic small molecules and polymers. She uses computational models to predict the relationships between structure and properties. The models can also be used to predict the properties of amorphous frameworks and porous molecules. Her group identified the 20 most probable topologies for porous cage molecules, which can be synthesised through dynamic covalent chemistry.
In 2018 Jelfs was awarded the Harrison-Meldola Memorial Prize from the Royal Society of Chemistry. She was also awarded an Imperial College London President's Award for Outstanding Early Career Research. In 2019, she was awarded a Philip Leverhulme Prize in Chemistry.
References
computational chemists
living people
year of birth missing (living people) | Kim Jelfs | [
"Chemistry"
] | 360 | [
"Computational chemistry",
"Theoretical chemists",
"Computational chemists"
] |
57,569,328 | https://en.wikipedia.org/wiki/Vela%201A | Vela 1A (or Vela 1) was a military satellite developed to detect nuclear detonations to monitor compliance with the 1963 Partial Test Ban Treaty by the Soviet Union.
Launch
Vela 1A was launched on October 17, 1963 from the Cape Canaveral Air Force Station, Florida, by an Atlas-Agena launch vehicle. Vela 1A was launched along with Vela 1B and with ERS 12.
Mission
Vela 1A was a spin-stabilized 124-kg satellite comprising the first launch in a series of six Vela launches. Together with its twin Vela 1B, their objectives were to monitor nuclear weapons explosions in space and to study x-rays, gamma-rays, neutrons, and charged particles as the satellites passed through interplanetary space, the bow shock, the magnetosheath, and the magnetotail.
See also
Vela (satellite)
References
1963 in spaceflight
Military space program of the United States | Vela 1A | [
"Astronomy"
] | 191 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
57,569,622 | https://en.wikipedia.org/wiki/Espruino | Espruino is an open-source JavaScript interpreter for single-board microcontrollers. It is designed for devices with small amounts of RAM (as low as 8 kiB).
Overview
Espruino was created by Gordon Williams in 2012 as an attempt to make microcontroller development truly multiplatform. Though initially not open-source, the Espruino firmware was offered as a free download for STM32 microcontrollers. It was made open-source in 2013 after a successful Kickstarter campaign for a development board running the software. Since the original Espruino board, there have been a number of new official development boards including the small USB thumb-drive-sized Espruino Pico, the Wifi-equipped Espruino WiFi, the Puck.js with built-in Bluetooth and the Pixl.js with a built-in LC display and Arduino shield compatibility. Espruino is the operating system used on the BangleJS and BangleJS2 smartwatches. In addition to the official boards, Espruino runs on approximately 40 other types of development boards including the ESP8266.
There is a large body of reference material for Espruino including over 100 tutorials as well as the book Making Things Smart which contains a selection of hardware projects that can be created with Espruino-based microcontrollers.
To achieve maximal memory efficiency, Espruino executes code from source directly inside the parser, without the use of an Abstract Syntax Tree or intermediate bytecode.
Hardware
The first official development board was the Original Espruino. Later boards are available in a variety of form factors. The Original Espruino was followed by the Espruino Pico, Espruino WiFi, Puck.js and Pixl.js. A breakout board featuring the MDBT42Q Bluetooth LE module, the same used in the Puck.js and Pixl.js, is also available.
Software
Espruino programs are written using JavaScript. The Espruino IDE is available as a web-based app, a Google Chrome App and as a native Windows application. Alternative methods of programming Espruino boards include using terminal programs such as PuTTY on Windows.
License
All of Espruino is open source. The different parts are licensed as follows:
Espruino Firmware - Mozilla Public License, version 2.0
Espruino Code Samples - MIT License
Espruino Documentation - Creative Commons Attribution-ShareAlike 3.0
Espruino Hardware Design Files - Creative Commons Attribution-ShareAlike 3.0
See also
MicroPython
References
JavaScript
Microcontrollers
Microcontroller software
Physical computing
Internet of things | Espruino | [
"Engineering"
] | 601 | [
"Physical computing",
"Robotics engineering"
] |
57,569,740 | https://en.wikipedia.org/wiki/Open%20microfluidics | Microfluidics refers to the flow of fluid in channels or networks with at least one dimension on the micron scale. In open microfluidics, also referred to as open surface microfluidics or open-space microfluidics, at least one boundary confining the fluid flow of a system is removed, exposing the fluid to air or another interface such as a second fluid.
Types of open microfluidics
Open microfluidics can be categorized into various subsets. Some examples of these subsets include open-channel microfluidics, paper-based, and thread-based microfluidics.
Open-channel microfluidics
In open-channel microfluidics, a surface tension-driven capillary flow occurs and is referred to as spontaneous capillary flow (SCF). SCF occurs when the pressure at the advancing meniscus is negative. The geometry of the channel and contact angle of fluids has been shown to produce SCF if the following equation is true.
Where pf is the free perimeter of the channel (i.e., the interface not in contact with the channel wall), and pw is the wetted perimeter (i.e., the walls in contact with the fluid), and θ is the contact angle of the fluid on the material of the device.
Paper-based microfluidics
Paper-based microfluidics utilizes the wicking ability of paper for functional readouts. Paper-based microfluidics is an attractive method because paper is cheap, easily accessible, and has a low environmental impact. Paper is also versatile because it is available in various thicknesses and pore sizes. Coatings such as wax have been used to guide flow in paper microfluidics. In some cases, dissolvable barriers have been used to create boundaries on the paper and control the fluid flow. The application of paper as a diagnostic tool has shown to be powerful because it has successfully been used to detect glucose levels, bacteria, viruses, and other components in whole blood. Cell culture methods within paper have also been developed. Lateral flow immunoassays, such as those used in pregnancy tests, are one example of the application of paper for point of care or home-based diagnostics. Disadvantages include difficulty of fluid retention and high limits of detection.
Thread-based microfluidics
Thread-based microfluidics, an offshoot from paper-based microfluidics, utilizes the same capillary based wicking capabilities. Common thread materials include nitrocellulose, rayon, nylon, hemp, wool, polyester, and silk. Threads are versatile because they can be woven to form specific patterns. Additionally, two or more threads can converge together in a knot bringing two separate ‘streams’ of fluid together as a reagent mixing method. Threads are also relatively strong and difficult to break from handling which makes them stable over time and easy to transport. Thread-based microfluidics has been applied to 3D tissue engineering and analyte analysis.
Capillary filaments in open microfluidics
Open capillary microfluidics are channels that expose fluids to open air by excluding the ceiling and/or floor of the channel. Rather than rely on using pumps or syringes to maintain flow, open capillary microfluidics uses surface tension to facilitate the flow. The elimination of and infusion source reduces the size of the device and associated apparatus, along with other aspects that could obstruct their use. The dynamics of capillary-driven flow in open microfluidics are highly reliant on two types of geometric channels commonly known as either rectangular U-grooves or triangular V-grooves. The geometry of the channels dictates the flow along the interior walls fabricated with various ever-evolving processes.
Capillary filaments in U-groove
Rectangular open-surface U-grooves are the easiest type of open microfluidic channel to fabricate. This design can maintain the same order of magnitude velocity in comparison to V-groove. Channels are made of glass or high clarity glass substitutes such as polymethyl methacrylate (PMMA), polycarbonate (PC), or cyclic olefin copolymer (COC). To eliminate the remaining resistance after etching, channels are given hydrophilic treatment using oxygen plasma or deep reactive-ion etching(DRIE).
Capillary filaments in V-groove
V-groove, unlike U-groove, allows for a variety of velocities depending on the groove angle. V-grooves with sharp groove angle result in the interface curvature at the corners explained by reduced Concus-Finn conditions. In a perfect inner corner of a V-groove, the filament will advance indefinitely in the groove allowing the formation of capillary filament depending on the wetting conditions. The width of the groove plays an important role in controlling the fluid flow. The narrower the V-groove is, the better the capillary flow of liquids is even for highly viscous liquids such as blood; this effect has been used to produce an autonomous assay. The fabrication of a V-groove is more difficult than a U-groove as it poses a higher risk for faulty construction, since the corner has to be tightly sealed.
Advantages
One of the main advantages of open microfluidics is ease of accessibility which enables intervention (i.e., for adding or removing reagents) to the flowing liquid in the system. Open microfluidics also allows simplicity of fabrication thus eliminating the need to bond surfaces. When one of the boundaries of a system is removed, a larger liquid-gas interface results, which enables liquid-gas reactions. Open microfluidic devices enable better optical transparency because at least one side of the system is not covered by the material which can reduce autofluorescence during imaging. Further, open systems minimize and sometimes eliminate bubble formation, a common problem in closed systems.
In closed system microfluidics, the flow in the channels is driven by pressure via pumps (syringe pumps), valves (trigger valves), or electrical field. An example of one of these methods for achieving low flow rates using temperature-controlled evaporation has been described for an open microfluidics system, allowing for long incubation hours for biological applications and requiring small sample volumes. Open system microfluidics enable surface-tension driven flow in channels thereby eliminating the need for external pumping methods. For example, some open microfluidic devices consist of a reservoir port and pumping port that can be filled with fluid using a pipette. Eliminating external pumping requirements lowers cost and enables device use in all laboratories with pipettes.
Materials Solutions
Thankfully, while many problems exist with PDMS, many solutions have also been developed. To address the negative hydrophobicity and porosity that PDMS exhibits, researchers have started to use coatings such as BSA (bovine serum albumin) or charged molecules to create a layer between the native PDMS and the cells. Other researchers have successfully employed several of the Pluronic surfactants, a tri-block copolymer that has two hydrophilic blocks surrounding a hydrophobic core often used to increase the hydrophilic nature of numerous substrates, and even borosilicate glass coatings to address the hydrophobicity problem. Interestingly, treatment with either of the prior two compounds can result in prevention of non-specific protein adsorption, as they (and other coatings) form stable adsorption interactions with the PDMS, which aides in reducing PDSM interference with cell culture media. These compounds and materials can affect surface properties and should be carefully tested to note the impact on cultured cells. Researchers developed 3D scaffolding systems to mimic in vivo environments so that more cells and cell types can grow in an effort to address the problem that not all cell types can grow on PDMS. Like coating the PDMS, 3D scaffolding systems employ alternatives materials like ECM (extracellular matrix) proteins so rather than not binding the native PDMS, cells are more likely to bind to the proteins. Lastly, researchers have addressed the permeability of PDMS to water vapor using some elegant solutions. For example, a portion of the microfluidic system can be designated for humidification and cast in PDMS, or other material like glass.
Disadvantages
Some drawbacks of open microfluidics include evaporation, contamination, and limited flow rate. Open systems are susceptible to evaporation which can greatly affect readouts when fluid volumes are on the microscale. Additionally, due to the nature of open systems, they are more susceptible to contamination than closed systems. Cell culture and other methods where contamination or small particulates are a concern must be carefully performed to prevent contamination. Lastly, open systems have a limited flow rate because induced pressures cannot be used to drive flow.
Materials
Polydimethylsiloxane (PDMS) is an ideal material to fabricate microfluidic devices for cell culture applications due to several advantageous properties such as low processing costs, ease of manufacture, rapid prototyping, ease of surface modification, and cellular non-toxicity. While there are several benefits that arise from using native Polydimethylsiloxane (PDMS), there are also some drawbacks that researchers must account for in their experiments. First, PDMS is both hydrophobic and porous, meaning that small molecules or other hydrophobic molecules can be adsorbed onto it. Such molecules include anything from methyl- or alkyl-containing molecules, and even certain dyes like Nile Red. Researchers identified in 2008 that plasma could be used to reduce the hydrophobicity of PDMS, though it returned about two weeks after treatment. Some researchers postulate that integrating removable polycaprolactone (PCL) fiber-based electrospun scaffolds under NaOH treatment enhances hydrophilicity as well as mitigating hydrophobicity, while promoting more efficient cell communication. Another problem that arises with PDMS is that it can interfere with the media that circulates in the channels. Incomplete curing of PDMS channels can lead to PDMS leaching into the media and, even when complete curing takes place, components of the media can still unintentionally attach to free hydrophobic sites on the PDMS walls. Yet another problem arises with the gas permeability of PDMS. Most researchers take advantage of this to oxygenate both the PDMS and the circulating media, but this trait also makes the microfluidic system especially vulnerable to water vapor loss. Lastly, not all cell types can grow, or will grow at the same levels, on native PDMS. For instance, high levels of rapid cell death in two fibroblast types grown on native PDMS were observed as early as 1994, which posed problems for the widespread use of PDMS in microfluidic cell culture.
Applications
Like many microfluidic technologies, open system microfluidics has been applied to nanotechnology, biotechnology, fuel cells, and point of care (POC) testing. For cell-based studies, open-channel microfluidic devices enable access to cells for single cell probing within the channel. Other applications include capillary gel electrophoresis, water-in-oil emulsions, and biosensors for POC systems. Suspended microfluidic devices, open microfluidic devices where the floor of the device is removed, have been used to study cellular diffusion and migration of cancer cells. Suspended and rail-based microfluidics have been used for micropatterning and studying cell communication.
Materials Solutions Applications
Applications of these solutions are still in use today, as seen by the following examples. In 2014, Lei et al. was testing the impedance of human oral cancer cells in the presence of cisplatin, a known anti-cancer drug, by molding the cells into a 3D scaffolding. The authors had noted from previous studies that cellular impedance could be correlated to cellular viability and proliferation in 2D cell culture and hoped to translate that correlation into 3D cell culture. Using agarose to create the 3D scaffolding, the researchers measured the growth and proliferation of human oral cancer cells in the presence and absence of cisplatin using fluorescent DNA assays and observed that there was indeed a correlation like that observed in 2D model. Not only did this prove that principles from 2D cell culture could be translated to 3D open microfluidic cell culture, but it also potentially lays the foundation for a more personalized treatment plan for cancer patients. They postulated that future developments could transform this method into an assay that could test patient cancer cell response to known anti-cancer drugs.
Another group used a similar method, but instead of creating a 3D scaffolding, they employed several different PDMS coatings to determine the best option for studying cancer stem cells. The group looked at BSA and ECM proteins and found that, while their experimental evidence supported BSA as the best coating for circulating cancer cells (CSC's), phenotypic changes did occur to the cells (namely, elongation), but did not impact the cells’ ability to perform normal cell functions. A key caveat to note here is that BSA is not a blanket solution that works for every cell type- different coatings work better or worse for certain cell types and these differences should be considered when developing an experiment.
References
Cell culture techniques
Microfluidics | Open microfluidics | [
"Chemistry",
"Materials_science",
"Biology"
] | 2,795 | [
"Biochemistry methods",
"Microfluidics",
"Cell culture techniques",
"Microtechnology"
] |
57,569,754 | https://en.wikipedia.org/wiki/Dentocorticium%20sulphurellum | Dentocorticium sulphurellum is a species of crust fungus in the family Polyporaceae. It is characterized by its toothed surface, its sulphur-yellow colour, and microscopically by the presence of dendrohyphidia in the hymenium. Charles Horton Peck originally described it in 1879 as Hydnum sulphurellum; it was transferred to Dentocorticium in 1974. It is found in North America and Japan.
References
Fungi described in 1879
Fungi of Japan
Fungi of North America
Polyporaceae
Taxa named by Charles Horton Peck
Fungus species | Dentocorticium sulphurellum | [
"Biology"
] | 120 | [
"Fungi",
"Fungus species"
] |
57,570,857 | https://en.wikipedia.org/wiki/Howard%20Carmichael | Howard John Carmichael (born 17 January 1950) is a British-born New Zealand theoretical physicist specialising in quantum optics and the theory of open quantum systems. He is the Dan Walls Professor of Physics at the University of Auckland and a principal investigator of the Dodd-Walls Centre. Carmichael has played a role in the development of the field of quantum optics and is particularly known for his Quantum Trajectory Theory (QTT) which offers a more detailed view of quantum behaviour by making predictions of single events happening to individual quantum systems. Carmichael works with experimental groups around the world to apply QTT to experiments on single quantum systems, including those contributing to the development of quantum computers. He is a Fellow of Optical Society of America, the American Physical Society and the Royal Society of New Zealand. He was awarded the Max Born Award in 2003, the Humboldt Research Award in 1997 and the Dan Walls Medal of the New Zealand Institute of Physics in 2017. In 2015, he was recognised as an Outstanding Referee by the American Physical Society.
Biography and education
Carmichael was born in Manchester England on January 17, 1950 and emigrated to New Zealand. He gained a BSc in physics and mathematics in 1971, and an MSc in physics in 1973 at the University of Auckland. It was here that Carmichael met New Zealand physicist Dan Walls, who supervised Carmichael's MSc in Auckland, and later his PhD at the University of Waikato from 1972 to 1977. Having just returned from PhD and postdoctoral studies with Roy Glauber at Harvard University and Hermann Haken at the University of Stuttgart, Walls brought the rapidly growing field of Quantum Optics to New Zealand, established a major research centre with an active strategy of collaborating with quantum optics groups around the world. During Carmichael's PhD studies, he and Walls made seminal contributions to the theoretical foundations of quantum optics. He then travelled to the United States for further postgraduate studies.
After post-doctoral positions at the City University of New York, and at the University of Texas at Austin (1979–1981) Carmichael was appointed as an assistant professor and later associate professor at the University of Arkansas. He was a visiting scientist at the Royal Signal and Radar Establishment in Malvern in 1984, visiting professor at the University of Texas at Austin in 1988 and at Caltech in 1989. In 1989 he was made associate professor, and in 1991 full professor, at the University of Oregon. He returned to New Zealand in 2002 to join the University of Auckland, becoming the inaugural Dan Walls Professor of Physics, a position he still holds today.
Research
Carmichael has made seminal contributions to the field of quantum optics and open quantum systems over more than four decades. He is known particularly for his development of quantum trajectory theory (1993), which offers a way to describe the evolution of a quantum system as it interacts with its environment. In 1993 he developed (at the same time as a separate formulation by Crispin Gardiner) the theory and application of cascaded quantum systems, in which the optical output of one quantum system becomes the optical input for another quantum system. He has also contributed to advances in the theory of nonclassical light and quantum correlation, quantum optical measurements, quantum fluctuations and noise in radiative processes, nonlinear physics and multi-photon processes, cavity quantum electrodynamics, quantum statistical methods and quantum entanglement.
Antibunched light
In 1976, while Carmichael was still a graduate student, he and his doctoral supervisor Dan Walls published a seminal paper that predicted photon antibunching, which led to the experimental demonstration of the quantum nature of light. The paper was based on their work with master equation techniques to describe open quantum systems, which Carmichael began during his masters. They had decided to investigate resonance fluorescence because it seemed like a good application of their master equations to two coupled open quantum systems. There was considerable international interest among the fledgling quantum optics community, in both experimental and theoretical resonance fluorescence. Using their newly developed master equation techniques, Walls and Carmichael derived the form of the fluorescence spectrum that agreed with previous experimental results. They went on to calculate the second-order correlation function to explore the statistics of resonance fluorescence. They were able to use the correlation function to explain how jumps of an emitting atom imprint on the emitted photon stream. They predicted that the correlation function should drop to zero at zero time delay and suggested a Quantum Electrodynamics (QED) experiment to test their predictions. These experiments were performed shortly afterwards providing evidence of the quantum character of the light emitted in resonance fluorescence.
Quantum trajectory theory (QTT)
Carmichael developed quantum trajectory theory (QTT) in the early 1990s, around the same time as the separate formulations by Dalibard Castin & Mølmer, and by Zoller, Ritsch & Dum). QTT (also known as quantum jump method or Monte Carlo wave function (MCWF)) is a formulation of quantum mechanics that tracks the path that a quantum object takes through the space of all its possible states as it is measured.
QTT is compatible with the standard formulation of quantum theory, as described by the Schrödinger equation, but offers a more detailed view. The Schrödinger equation, is a probabilistic theory. It gives the probability of finding a quantum system in each of its possible states should a measurement be made. This is useful for predicting average measurements of large ensembles of quantum objects but it does not describe the behaviour of individual particles. QTT fills this gap by offering a way to describe the trajectories of individual quantum particles that obey the probabilities given by the Schrödinger equation. QTT also works with open quantum systems that interact with their environment unlike the Schrödinger equation which only describes a quantum system in isolation. QTT has become particularly popular since the technology has become available to efficiently control and monitor individual quantum systems as it can predict how individual quantum objects such as particles will behave when they are observed.
In QTT open quantum systems are modelled as scattering processes, with classical external fields corresponding to the inputs and classical stochastic processes corresponding to the outputs (the fields after the measurement process). The mapping from inputs to outputs is provided by a quantum stochastic process that is set up to account for a particular measurement strategy (eg., photon counting, homodyne/heterodyne detection, etc).
QTT addresses the measurement problem in quantum mechanics by providing a detailed description of what happens during the so-called "collapse of the wave function". It reconciles the concept of a quantum jump with the smooth evolution described by the Schrödinger equation. The theory suggests that "quantum jumps" are not instantaneous but happen in a coherently driven system as a smooth transition through a series of superposition states. This prediction was tested experimentally in 2019 by a team at Yale University led by Michel Devoret and Zlatko Minev in collaboration with Carmichael and others at Yale University and the University of Auckland. In their experiment they used a superconducting artificial atom to observe a quantum jump in detail, confirming that the transition is a continuous process that unfolds over time. They were also able to detect when a quantum jump was about to occur and intervene to reverse it, sending the system back to the state in which it started. This experiment, inspired and guided by QTT, represents a new level of control over quantum systems and has potential applications in correcting errors in quantum computing in the future.
Books
Howard Carmichael (1999, 2002) An Open Systems Approach to Quantum Optics 1; Springer, Berlin Heidelberg ( )
H J Carmichael (1999, 2002) Statistical Methods in Quantum Optics 1: Master Equations and Fokker‐Planck Equations; Springer, Berlin Heidelberg ( )
H J Carmichael (2008) Statistical Methods in Quantum Optics 2: Non-Classical Fields; Springer, Berlin Heidelberg ( )
H J Carmichael, R J Glauber and M O Scully (Eds) (2001) Directions in Quantum Optics; Springer, Berlin Heidelberg ()
Honours and awards
Dan Walls Medal of the New Zealand Institute of Physics (2017)
Fellow of the Royal Society of New Zealand (2006)
The Max Born Award of the Optical Society of America (2003)
Humboldt Research award for Senior United States Scientists, Alexander Humboldt Foundation (1997)
Fellow of the American Physical Society (1995)
Fellow of the Optical Society of America (1990)
References
1950 births
Living people
Optical physicists
Quantum physicists
Theoretical physicists
University of Auckland alumni
Fellows of the American Physical Society
Fellows of Optica (society)
Fellows of the Royal Society of New Zealand
20th-century New Zealand physicists
21st-century New Zealand physicists | Howard Carmichael | [
"Physics"
] | 1,741 | [
"Theoretical physics",
"Quantum physicists",
"Theoretical physicists",
"Quantum mechanics"
] |
57,574,496 | https://en.wikipedia.org/wiki/Contracted%20Bianchi%20identities | In general relativity and tensor calculus, the contracted Bianchi identities are:
where is the Ricci tensor, the scalar curvature, and indicates covariant differentiation.
These identities are named after Luigi Bianchi, although they had been already derived by Aurel Voss in 1880. In the Einstein field equations, the contracted Bianchi identity ensures consistency with the vanishing divergence of the matter stress–energy tensor.
Proof
Start with the Bianchi identity
Contract both sides of the above equation with a pair of metric tensors:
The first term on the left contracts to yield a Ricci scalar, while the third term contracts to yield a mixed Ricci tensor,
The last two terms are the same (changing dummy index n to m) and can be combined into a single term which shall be moved to the right,
which is the same as
Swapping the index labels l and m on the left side yields
See also
Bianchi identities
Einstein tensor
Einstein field equations
General theory of relativity
Ricci calculus
Tensor calculus
Riemann curvature tensor
Notes
References
Concepts in physics
Tensors
General relativity | Contracted Bianchi identities | [
"Physics",
"Engineering"
] | 220 | [
"Tensors",
"General relativity",
"Relativity stubs",
"nan",
"Theory of relativity"
] |
57,574,752 | https://en.wikipedia.org/wiki/The%20Hitching%20Stone | The Hitching Stone is a gritstone erratic block on Keighley Moor, North Yorkshire, near Earl Crag and the village of Cowling. It is very close to the border between North Yorkshire and West Yorkshire and the border between Yorkshire and Lancashire.
It is said to be the largest boulder in Yorkshire at long, wide and high. It is also said to weigh a lot more than 1000 tonnes.
Geography
The Hitching Stone is from the town of Keighley and is at an elevation of .
History
The Hitching Stone and all the other erratic boulders on Keighley Moor were put in place thousands to possibly millions of years ago during the Pleistocene Epoch. The Hitching Stone most likely originally came from Earl Crag during this time. As a result of the fact that The Hitching Stone lies at the borders of historic counties, ancient councils and parliaments met at the stone and markets, fairs, and other gatherings were also held at the stone, with the last fair being held in 1870.
Gallery
See also
List of individual rocks
Lund’s Tower
Wainman’s Pinnacle
References
Further reading
T. Sharpe, The Pendle Zodiac, Thomas Sharpe, February 20, 2012. Exploring the Sacred Geometry, Ley alignments and recent Landscape Zodiac discoveries of Pendle - in the Rose County of Lancashire - from the perspective of Spiritual Science.
Stones
Sandstone formations | The Hitching Stone | [
"Physics"
] | 274 | [
"Stones",
"Physical objects",
"Matter"
] |
57,575,944 | https://en.wikipedia.org/wiki/Proteinase%20inhibitors%20in%20plants | In plant biology, proteinase inhibitors are a family of small proteins that serve an integral role in the plant’s defense mechanisms against herbivory from insects or microorganisms that may compromise the integrity of the plant.
Functionality
The proteinase inhibitors work to disrupt the enzymatic ability of the digestive or microbial enzymes that are present in the stomach of the attacker resulting in the inability to properly digest the plant material. This causes an interference of proper growth and discourages further wounding of the plant by the attacker. Studies have also recently revealed that some proteinase inhibitors also provide defense for the plant through the possession of antimicrobial properties providing for the inhibition of pathogen growth.
Wounding
While proteinase inhibitors are present in plants naturally, production of these proteins for defense is often induced by either wounding of the plant or by chemical signaling through molecules such as methyl jasmonate. Both wounding of the plant as well as signaling molecules result in the formation of jasmonic acid, which then induces the gene expression of proteinase inhibitors. Many other signal cascades as well as the translocation of signal molecules through the phloem and xylem of the plant are also necessary for the production of these inhibitors.
Once the proteinase inhibitor has been ingested by the insect, it presents itself as a normal substrate for the digestive enzymes binding to the active site on the enzyme. This binding of the inhibitor to the proteinase creates a new complex that is very unlikely to dissociate. Once bound, the active site can no longer be accessed by any other substrate and the enzyme can no longer digest the amino acids of the plant. Without proper digestion, the insect is unable to grow, and may starve if it chooses to remain at the wounded plant. Similar inhibition of growth can be seen in pathogens that interact with these inhibitors.
Tomato experiment
In order to discover how the production of the inhibitors was induced, scientists exposed tomato plants to different forms of methyl jasmonate and then assayed using radial immunodiffusion for proteinase inhibitors in leaf juices. A group of tomato plants was sprayed with a solution containing methyl jasmonate, while another group of tomato plants was exposed to methyl jasmonate vapor in air-tight glass chambers. Control groups were sprayed with a solution or exposed to a vapor that did not contain methyl jasmonate. Both experimental groups revealed increased proteinase inhibitor production as a result of exposure to volatile methyl jasmonate in comparison to control groups.
Defense behavior
The production of proteinase inhibitors reveals that plants have the ability to alter their defense behavior in response to a threat or direct attack on plant integrity. This complex defense mechanism serves to not only protect the plant from being eaten, but also from pathogen infection requiring both coordination and communication.
References
Botany
Plant physiology
Protease inhibitors | Proteinase inhibitors in plants | [
"Biology"
] | 573 | [
"Plant physiology",
"Plants",
"Botany"
] |
57,575,956 | https://en.wikipedia.org/wiki/Mycorrhizal%20bioremediation | Mycorrhizal amelioration of heavy metals or pollutants is a process by which mycorrhizal fungi in a mutualistic relationship with plants can sequester toxic compounds from the environment, as a form of bioremediation.
Mycorrhizae-plant partners
These symbiotic relationships are generally between plants and arbuscular mycorrhizae in the Glomeromycota clade of fungi. Other types of fungi have been documented. For example, there is a case where zinc phytoextraction from willows was increased after the Basidiomycete fungus Paxillus involutus was inoculated in the soil.
Mechanisms of the symbiosis
The mycorrhizae allow the plants to increase their biomass, which increases their tolerance to heavy metals. The fungi also stimulate the uptake of heavy metals (such as manganese and cadmium) with the enzymes and organic acids (such as acetic acid and malic acid) that they excrete into their surroundings in order to digest them.
Mycorrhizae on plant toleration
The fungi can prevent heavy metals from traveling past the roots of the plant. They can also store heavy metals in their vacuoles. However, in some cases, the fungi do not decrease the uptake of heavy metals by plants but increase their tolerance. In some cases, this is done by increasing the overall biomass of the plant so that there is a lower concentration of metals. They can also modify the response of the plant to heavy metals at the level of plant transcription and translation.
Colonization of barren soil
Mycorrhizae remain functional underground following extreme conditions, such as a forest fire. Researchers believe that this allows them to obtain minerals and nutrients that are released during a fire before they are leached out of the soil. This likely increases the ability to recover quickly after forest fires.
Serpentine soils are in part characterized by a low calcium-to-magnesium ratio. Studies indicate that arbuscular mycorrhiza helps plants increase their magnesium uptake in soils with low amounts of magnesium. However, plants in serpentine soils inoculated with fungus either showed no effect on magnesium concentration or decreased magnesium uptake.
Resistance to toxicity
Studies show that mycorrhizal symbionts of poplar seedlings are capable of preventing heavy metals reaching vulnerable parts of the plant by keeping the toxins in the rhizosphere. Another study demonstrates that Arctostaphylos uva-ursi plants in symbiotic relationships were more resistant to toxins because the fungi helped the plants grow below toxic layers of soil.
Application in bioremediation
In China's provinces of Guizhou, Yunnan and Guangxi, rocky desertification is expanding and is not well controlled. This area is characterized by soil depletion, soil erosion and droughts. It is very difficult for plants to grow in this region, and it is mostly filled with drought-resistant plants, lithophytes and calciphilopteris plants. Morus alba, commonly known as a mulberry, is a drought-resistant tree that can tolerate barren soils. It has been found that mulberry inoculated with arbuscular mycorrhiza has increased survivability in karst desert areas and, therefore, an increased rate of soil improvement and reduced erosion.
In 1993, artist Mel Chin collaborated with USDA agronomist Dr. Rufus Chaney in an effort to detoxify Pigs Eye Landfill, a superfund site in Saint Paul, Minnesota. The team planted Thlaspi, which had been selected for increased uptake and sequestration of heavy metals. Analysis showed elevated cadmium concentrations in Thlaspi biomass. It has been found that Thlaspi has a significant arbuscular mycorrhiza association.
Slovakia has many heavy metal mines, which have caused significant regional soil contamination. Samples of Thlaspi harvested in Slovakia from contaminated soils near a lead mine showed increased levels of cadmium, lead, and zinc. Furthermore, Thlaspi growing in contaminated regions had higher rates of certain arbuscular mycorrhizal fungi when compared to non-contaminated Thlaspi. Since manual clean-up is usually inefficient and expensive, mycorrhiza colonized Thlaspi may be useful in bioremediation efforts.
See also
Bioremediation
Mycoremediation
Phytoremediation
References
Bioremediation | Mycorrhizal bioremediation | [
"Chemistry",
"Biology",
"Environmental_science"
] | 920 | [
"Biodegradation",
"Ecological techniques",
"Environmental soil science",
"Bioremediation"
] |
57,576,285 | https://en.wikipedia.org/wiki/Pump%20dispenser | A pump dispenser is used on containers of liquids to help dispensing. They might be used on bottles, jars, or tubes. Often the contents are viscous liquids such as creams and lotions. Some are metered to provide uniform usage. Some mix contents from two or more sources prior to dispensing.
Typical products
Liquid soap
Moisturizer
Toothpaste
Lotion
Cosmetics
Pharmaceuticals
Functioning
Several types of pumps and dispensing systems have been developed.
Some of the pumps are similar to those of spray bottles.
Examples
See also
Pump
Toothpaste pump dispenser
Drum pump
Further reading
Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, pp 275–276, 2009,
Soroka, W, "Fundamentals of Packaging Technology", IoPP, 2002,
Standards, ASTM International
D3890 Standard Test Method for Number of Strokes to Prime a Mechanical Pump Dispenser
D4333 Test Method for the Compatibility of Mechanical Pump Dispenser Components
D4334 Standard Test Method for the Determination of the Dip Tube Retention of a Mechanical Pump Dispenser
D4335 Standard Test Method for Determination of Component Retention of a Mechanical Pump Dispenser
D4336 Standard Test Methods for Determination of the Output Per Stroke of a Mechanical Pump Dispenser
D6534 Standard Test Method for Determining the Peak Force-to-Actuate a Mechanical Pump Dispenser
D6535 Standard Test Method for Determining the Dip Tube Length of a Mechanical Pump Dispenser
D6536 Standard Test Method for Measuring the Dip Tube Length of a Mechanical Pump Dispenser
D6633 Standard Test Method for Basic Functional Stability of a Mechanical Pump Dispenser
D6654 Standard Test Method for Basic Storage Stability of a Mechanical Pump Dispenser
References
Packaging
Pumps | Pump dispenser | [
"Physics",
"Chemistry"
] | 379 | [
"Physical systems",
"Hydraulics",
"Turbomachinery",
"Pumps"
] |
57,577,163 | https://en.wikipedia.org/wiki/Crispin%20Gardiner | Crispin William Gardiner (born 18 October 1942) is a New Zealand physicist, who has worked in the fields of quantum optics, ultracold atoms and stochastic processes. He has written about 120 journal articles and several books in the fields of quantum optics, stochastic processes and ultracold atoms.
Education
Born in Hastings New Zealand, Crispin Gardiner completed his undergraduate studies at the University of Auckland (B. Sc. 1964, M. Sc. 1965). He was awarded a research scholarship by the Royal Commission for the Exhibition of 1851 in 1965, under which received his DPhil in 1968 from the Oxford University for research in elementary particle physics.
Career
Following his DPhil, Gardiner completed postdoctoral research in the group of
George Sudarshan at the Syracuse University.
University of Waikato, 1970–1995
Gardiner was appointed to the faculty of the Physics Department of the University of Waikato in 1970, and was awarded a personal chair in physics in 1992, a position held until 1995.
When Gardiner arrived, the University of Waikato was only 5 years old, while the School of Science, which covered Physics, Mathematics, Chemistry, Biology and Earth Science, had only commenced teaching at the beginning of 1970, and no research facilities had been established.
Dan Walls took up a position at Waikato in 1972, and, working together, he and Gardiner established a major research centre for theoretical quantum optics at Waikato, building active and productive collaborations with groups throughout the world.
During this period
He and Peter Drummond developed the positive P-representation
He and Matthew Collett developed the input-output formalism for damped quantum systems, which they used to predict and describe the spectrum of squeezed light.
He wrote the first (1985) edition of the book Stochastic Methods, now seen as a standard text in the field of applied stochastic processes.
In 1986 he predicted the inhibition of atomic phase decays for a two-level atom coupled to a squeezed optical reservoir. While challenging to realise in optical systems, the phenomenon was eventually observed in a superconducting qubit system affording sufficient reservoir control.
He wrote the first (1991) edition of the book Quantum Noise, (later editions were written in collaboration with Peter Zoller) which has become a standard text in the fields of quantum optics and quantum stochastic methods.
In 1993 he developed (at the same time as a separate formulation by Howard Carmichael) the theory and application of cascaded quantum systems, in which the optical output of one quantum system becomes the optical input for another quantum system.
Work in early childhood education, 1971–1991
A very significant part of Gardiner's activity over the years 1971-1991 was as a parent activist, administrator and government consultant in New Zealand early childhood education. During this period very significant expansion of recognition, provision and government funding for early childhood education occurred.
In particular
He was one of the group which founded the "Campus Creche Society" in 1971, of which he was the secretary until 1974. The Campus Creche Society, advocated, and established the first Childcare Centre in the University of Waikato.
He was elected to the executive of the N.Z. Childcare Association in 1975, becoming Vice President 1983–1984.
In 1976 he organised the Hamilton Day Care Centres Trust, which operated childcare services in Hamilton, and administered the government Childcare Subsidy in the full Waikato region. He was chairman of The Trust 1976–1984.
He worked for the Government in the development of policies and funding mechanisms for Early Childhood Education, as a member of several official boards and working parties, or as a consultant to the Ministry of Education.
Independent researcher at Victoria University of Wellington, 1995–2005
In 1995 he left the University of Waikato and for the next nine years worked as an independently funded researcher affiliated to Victoria University of Wellington. This was funded by the New Zealand R&D system, which was willing to fund individuals outside established institutions, and was motivated by the opportunity to leave the increasingly bureaucratic New Zealand University system.
During this period his work concentrated on the physics of Ultracold atoms, developing a collaboration with Rob Ballagh of the University of Otago. They produced number of influential scientific publications, mainly concentrating on kinetic processes in Bose–Einstein condensates, funded by successive research contracts with the Marsden Fund
and in particular seven papers on quantum kinetic theory
.
Gardiner characterised this period as "In terms of productivity, it has been the best 10 years research of my life."
University of Otago, 2005–2013
In 2005 he was appointed as a Research Professor at the University of Otago. In this period he was active in developing the University of Otago as a major research centre in ultracold atoms, photonics and quantum optics, which was named the Jack Dodd Centre, after former Otago professor Jack Dodd. During this period there was a major reorganisation of government research funding, commencing in 2006, which he and Rob Ballagh strongly criticised, on the grounds that this would exclude university research from any major funding. Ultimately this aspect of the funding reform was not implemented, and in 2007 the Jack Dodd Centre was awarded a $6.4 million research contract by the Foundation for Research, Science and Technology.
From that time on, as director of the Jack Dodd Centre, his role developed more into that of a research leader until his retirement in early 2013.
Retirement
On retirement he became an honorary professor at the University of Otago and in 2016 he accepted a position as visiting fellow at the Institute for Quantum Optics and Quantum Information (IQOQI) in Innsbruck.
During this period he and Peter Zoller wrote the three books of The Quantum World of Ultra-Cold Atoms and Light.
Books
C W Gardiner: A Handbook of Stochastic Methods; Springer, Berlin Heidelberg, 1st ed. 1983; 2nd ed. 1985, 1989, 1998, 2001; 3rd Ed 2004, Russian Edition 1986 (Mir, Moscow)
Crispin Gardiner: Stochastic Methods; Springer, Berlin Heidelberg, 2009 (A rewritten and updated 4th edition of A Handbook of Stochastic Methods)
Crispin Gardiner: Elements of Stochastic Methods; AIP Publishing (online), Melville, New York, 2021, available at: https://doi.org/10.1063/9780735423718
C W Gardiner: Quantum Noise; Springer, Berlin Heidelberg, 1st ed. 1991
C W Gardiner and Peter Zoller: Quantum Noise; Springer, Berlin Heidelberg, 2nd ed. 1999, 3rd ed. 2004
Crispin Gardiner and Peter Zoller: The Quantum World of Ultra-Cold Atoms and Light Book I: Foundations of Quantum Optics, Imperial College Press, London and Singapore 2014.
Crispin Gardiner and Peter Zoller: The Quantum World of Ultra-Cold Atoms and Light Book II: Physics of Quantum Optical Devices, Imperial College Press, London and Singapore 2015.
Crispin Gardiner and Peter Zoller: The Quantum World of Ultra-Cold Atoms and Light Book III: Ultra-Cold Atoms, World Scientific, London and Singapore 2014.
Awards and honours
1983 Fellow of the New Zealand Institute of Physics
1984 Fellow of the American Physical Society
1990 Fellow of the Royal Society of New Zealand (Until 2011)
2000 Honorary Dr. Rer. Nat. from the University of Innsbruck: In recognition of his outstanding scientific merit in the field of theoretical quantum optics
References
1942 births
Living people
People from Hastings, New Zealand
Optical physicists
Quantum physicists
Theoretical physicists
University of Auckland alumni
Alumni of Linacre College, Oxford
Academic staff of the University of Otago
Academic staff of the University of Waikato
Fellows of the Royal Society of New Zealand
Fellows of the American Physical Society
20th-century New Zealand physicists
21st-century New Zealand physicists | Crispin Gardiner | [
"Physics"
] | 1,557 | [
"Theoretical physics",
"Quantum physicists",
"Theoretical physicists",
"Quantum mechanics"
] |
57,577,573 | https://en.wikipedia.org/wiki/Simon%20problems | In mathematics, the Simon problems (or Simon's problems) are a series of fifteen questions posed in the year 2000 by Barry Simon, an American mathematical physicist. Inspired by other collections of mathematical problems and open conjectures, such as the famous list by David Hilbert, the Simon problems concern quantum operators. Eight of the problems pertain to anomalous spectral behavior of Schrödinger operators, and five concern operators that incorporate the Coulomb potential.
In 2014, Artur Avila won a Fields Medal for work including the solution of three Simon problems. Among these was the problem of proving that the set of energy levels of one particular abstract quantum system was, in fact, the Cantor set, a challenge known as the "Ten Martini Problem" after the reward that Mark Kac offered for solving it.
The 2000 list was a refinement of a similar set of problems that Simon had posed in 1984.
Context
Background definitions for the "Coulomb energies" problems ( non-relativistic particles (electrons) in with spin and an infinitely heavy nucleus with charge and Coulombic mutual interaction):
is the space of functions on which are asymmetrical under exchange of the spin and space coordinates. Equivalently, the subspace of which is asymmetrical under the exchange of the factors.
The Hamiltonian is . Here is the coordinate of the -th particle, is the Laplacian with respect to the coordinate . Even if the Hamiltonian does not explicitly depend on the state of the spin sector, the presence of spin has an effect due to the asymmetry condition on the total wave-function.
We define , that is, the ground state energy of the system.
We define to be the smallest value of such that for all positive integers ; it is known that such a number always exists and is always between and , inclusive.
The 1984 list
Simon listed the following problems in 1984:
In 2000, Simon claimed that five of the problems he listed had been solved.
The 2000 list
The Simon problems as listed in 2000 (with original categorizations), are:
See also
Almost Mathieu operator
Lieb–Thirring inequality
External links
References
unsolved problems in mathematics
Unsolved problems in physics
Mathematical physics | Simon problems | [
"Physics",
"Mathematics"
] | 456 | [
"Unsolved problems in mathematics",
"Applied mathematics",
"Theoretical physics",
"Unsolved problems in physics",
"Mathematical problems",
"Mathematical physics"
] |
57,578,128 | https://en.wikipedia.org/wiki/Courage%20to%20Care | Courage to Care (also known as B'nai B'rith Courage to Care) is an organization based in Australia founded by the Jewish service organization B'nai B'rith. The group's mission is to prevent discrimination and bullying through educational programs.
The organisation's programme is student-centred, focused exclusively on the stories of people who rescued Jews during the Holocaust. The programme's aim is to convey community tolerance and living in harmony.
Courage to Care has three divisions, one based in Sydney, New South Wales (covering the states of New South Wales and Queensland), one in Melbourne, Victoria, and one based in Perth, Western Australia.
Activities
Courage to Care operates a traveling exhibition featuring stories of Holocaust survivors and those who rescued them.
Other activities include programs and workshops for schools and workplaces.
In 2016, the program was delivered for new recruits at the Queensland Police Service.
See also
Courage to Care Award
The Courage to Care (film)
Ernie Friedlander - anti-racism activist associated with B'nai B'rith and Courage to Care
Moving Forward Together
Alan Gold (author) - former Vice-President of Courage to Care
Anti-Defamation Commission
References
External links
Courage to Care NSW / QLD website
Courage to Care Victoria website
Courage to Care Perth website
Educational organisations based in Australia
Jewish organisations based in Australia
The Holocaust
Organisations based in Sydney
Organisations based in Melbourne
Organisations based in Perth, Western Australia | Courage to Care | [
"Biology"
] | 289 | [
"Rescue of Jews during the Holocaust",
"Behavior",
"Altruism"
] |
57,578,297 | https://en.wikipedia.org/wiki/NGC%203312 | NGC 3312 is a large and highly inclined spiral galaxy located about 194 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 26, 1835. It was later rediscovered by astronomer Guillaume Bigourdan on February 26, 1887. NGC 3312 was later listed and equated with IC 629 because the two objects share essentially the same celestial coordinates. NGC 3312 is the largest spiral galaxy in the Hydra Cluster and is also classified as a LINER galaxy.
Physical characteristics
NGC 3312 appears to be highly distorted with sharp dust lanes. There are sharp filamentary extensions to the north and an internal ringlike structure in the galaxy. The interstellar matter in the galaxy also appears highly disturbed. These features caused astronomer De Vaucouleurs to suggest that NGC 3312 was distorted by the giant elliptical galaxies NGC 3309 and NGC 3311 which are the dominant ellipticals in the Hydra Cluster. However, NGC 3309 and NGC 3311 are too distant and their relative velocity differences too large for either elliptical to cause the filamentary extensions observed in NGC 3312. It is more likely that NGC 3312 is interacting with the intracluster medium causing ram-pressure stripping which is stripping the interstellar medium of the galaxy. This may have caused the filamentary extensions observed in NGC 3312 as evidenced by the location of the galaxy near the cluster core. As a result, this galaxy can be considered part of a rare class of galaxies, known as jellyfish galaxies.
Star formation
Although NGC 3312's morphological structure resembles that of anemic galaxies, its mean surface-brightness profile hints that star formation may be quite active. The northwest filamentary extension from NGC 3312 has high surface brightness and has the knotted texture characteristic of active star-forming regions in spiral arms. Also, the internal dust lane of NGC 3312 is ringed with bright condensations.
Radio source
NGC 3312 contains an unresolved strong radio source in its core with a strength of 27 mJy and radio emission in the disk with a strength of 24 mJy mostly being confined to the spiral arms of the galaxy or regions of star formation.
See also
List of NGC objects (3001–4000)
Messier 90
NGC 4921
References
External links
Hydra Cluster
Hydra (constellation)
Peculiar galaxies
LINER galaxies
Unbarred spiral galaxies
3312
31513
IC objects
Astronomical objects discovered in 1835
Discoveries by John Herschel | NGC 3312 | [
"Astronomy"
] | 501 | [
"Hydra (constellation)",
"Constellations"
] |
57,578,813 | https://en.wikipedia.org/wiki/Feodor%20Ivanovich%20Vilesov | Feodor Ivanovich Vilesov (; 13 November 1925 – 8 February 1978) was a Soviet experimental physicist whose main contributions are in the field of chemical physics.
Education and early life
Vilesov was born in Belyukovo village near Kudymkar, in Komi-Permyak Okrug (autonomous national district), Perm region, Russian SFSR, Soviet Union, on November 13, 1925, to a couple of: Ivan Ilvich Vilesov and Vassa Vasilievna Vilesova. During 1943 -1950 he served in the Soviet Army. In 1950 he entered the Department of Physics, Leningrad State University, from which he graduated with an honorable diploma (master's degree) in 1955. He continued with his Ph. D. studies at the Institute of Physics, Leningrad State University, in the department of photonics led by Professor A. N. Terenin and in 1959 he defended his thesis “The Study of Photoionization of vapors of organic molecules and interrogation of the influence of adsorbed layers on photoelectric Emission from Semiconductor Catalysts”. He obtained his Doctor of Physical and Mathematical Sciences (a "higher doctorate") degree in 1966 for a thesis on the development of photoelectron spectroscopy in the gas phase and molecular solids entitled: “Photoionization of Organic Molecules”
Career
From 1955 to 1978, he worked at the Institute for Physics of the Leningrad State University. Since 1964, he was the head of the department of photonics (photochemistry). In 1967 he becomes a professor in physics at Leningrad State University. In 1977-1978 he served as the dean of sciences of the Leningrad State University.
In a series of works in 1960–1962, Vilesov and his colleagues performed the first experiments on Ultraviolet Photoelectron Spectroscopy (UPS) of molecular solids and gases. Since then Ultraviolet Photoelectron Spectroscopy has been widely applied to study valence energy levels and chemical bonding, especially the bonding character of molecular orbitals.
Honors and awards
Vilesov was awarded the USSR State Prize in 1985, —for the development of the method of photoelectron spectroscopy and its application in science and technology, published in 1961–1985.
Personal life
Vilesov was the son of Ivan Ivanovich Vilesov (1906-1967) and Vassa Vasilievna (1905-1984). He was married to Vera Konstantinovna Adamchuk (1933-2016) and had 1 child, Andrey Feodorovich Vilesov.
He died on 8 February 1978 at the age of 52.
References
1925 births
1978 deaths
Soviet physicists
Experimental physicists
Soviet inventors | Feodor Ivanovich Vilesov | [
"Physics"
] | 533 | [
"Experimental physics",
"Experimental physicists"
] |
62,773,982 | https://en.wikipedia.org/wiki/Radcliffe%20wave | The Radcliffe wave is a neighbouring coherent gaseous structure in the Milky Way, dotted with a related high concentration of interconnected stellar nurseries. It stretches about 8,800 light years. This structure runs with the trajectory of the Milky Way arms.
It lies at its closest (the Taurus Molecular Cloud) at around 400 light-years and at its farthest about 5,000 light-years (the Cygnus X star complex) from the Sun, always within the Local Arm (Orion Arm) itself, spanning about 40% of its length and on average 20% of its width. Its discovery was announced in January 2020, and its proximity surprised astronomers.
Formation
Scientists do not know how the undulation of dust and gas formed. It has been suggested that it could be a result of a much smaller galaxy colliding with the Milky Way, leaving behind "ripples", or could be related to dark matter. Inside the dense clouds, gas can be so compressed that new stars are born. It has been suggested that this may be where the Sun originated.
Many of the star-forming regions found in the Radcliffe wave were thought to be part of a similar-sized but somewhat helio-centric ring which contained the Solar System, the "Gould Belt". It is now understood the nearest discrete relative concentration of sparse interstellar matter instead forms a massive wave.
Discovery
The wave was discovered by an international team of astronomers including Catherine Zucker and João Alves. It was announced by co-author Alyssa A. Goodman at the 235th meeting of the American Astronomical Society, held at Honolulu and published in the journal Nature on 7 January 2020. The discovery was made using data collected by the European Space Agency's Gaia space observatory.
The wave was invisible in 2D, requiring new 3D techniques of mapping interstellar matter to reveal its pattern using Glue (software). The proximity of the wave surprised astronomers. It is named after the Radcliffe Institute for Advanced Study in Cambridge, Massachusetts, the place of study of the team.
Structure and movement
The Radcliffe wave contains four of the five Gould Belt clouds:
Orion molecular cloud complex
Perseus molecular cloud
Taurus molecular cloud
Cepheus OB2
The cloud not within its scope is the Rho Ophiuchi Cloud complex, part of a linear structure parallel to the Radcliffe wave.
Other structures in the wave, further from the local star system, are Canis Major OB1, the North America Nebula and Cygnus X.
The mass of this structure is on the scale of . It has a length of 8,800 light-years (2,700 parsecs) and an amplitude of 520 light-years (160 parsecs). The Radcliffe wave occupies about 20% of the width and 40% of the length of the local arm (Orion Arm). The latter is more dispersed as to its interstellar medium than the wave and has further large star-forming regions such as Monoceros OB1, California Nebula, Cepheus Far, and Rho Ophiuchi.
A 2024 paper announced the discovery that the Radcliffe wave is oscillating in the form of a traveling wave.
See also
Antlia 2, another giant ripple across the Milky Way's disc found in data from the Gaia space telescope
List of nearby stellar associations and moving groups
Great Rift (astronomy)
Serpens-Aquila Rift
References
Further reading
External links
Interactive map of the Radcliffe wave on the sky
The Radcliffe Wave informational site created by Harvard University
Star formation
Stellar astronomy
Star-forming regions
Milky Way
Astronomical objects discovered in 2020 | Radcliffe wave | [
"Astronomy"
] | 723 | [
"Astronomical sub-disciplines",
"Stellar astronomy"
] |
62,774,758 | https://en.wikipedia.org/wiki/Frances%20Kuo | Frances Y. Kuo is an applied mathematician known for her research on low-discrepancy sequences and quasi-Monte Carlo methods for numerical integration and finite element analysis. Originally from Taiwan, she was educated in New Zealand, and works in Australia as a professor in applied mathematics at the University of New South Wales.
Education and career
Kuo is originally from Taipei, and went to high school in Taiwan. She moved to New Zealand in 1994, and became a student at the University of Waikato, completing a bachelor of computing and mathematical sciences with honours in 1998, and a PhD in 2001. Her dissertation, Constructive approaches to quasi-Monte Carlo methods for multiple integration, was supervised by Stephen Joe.
After a year as an assistant lecturer at Waikato, Kuo moved to the University of New South Wales (UNSW) to do postdoctoral research with Ian Sloan. She remained as an ARC QEII Fellow and in 2012 became a senior lecturer at UNSW. She became an ARC Future Fellow in 2013 and a professor in 2019.
Recognition
In 2011, Kuo won the JH Michell Medal of ANZIAM, given annually to outstanding new researchers. The award cited her leadership in "theory and applications of high dimensional integration and approximation, Monte-Carlo methods and information-based complexity" and her interest in "applications in finance, statistics and porous media flow". She was the 2014 winner of the Joseph F. Traub Prize for Achievement in Information-Based Complexity.
References
External links
Home page
Year of birth missing (living people)
Living people
21st-century Taiwanese mathematicians
Australian mathematicians
Women mathematicians
Australian women mathematicians
Applied mathematicians
University of Waikato alumni
Academic staff of the University of Waikato
Academic staff of the University of New South Wales | Frances Kuo | [
"Mathematics"
] | 352 | [
"Applied mathematics",
"Applied mathematicians"
] |
62,777,640 | https://en.wikipedia.org/wiki/Nikolay%20V.%20Kuznetsov | Nikolay Vladimirovich Kuznetsov (; born 13 May 1979 in Leningrad, USSR) is a specialist in nonlinear dynamics and control theory.
Academic career
He graduated from the St. Petersburg University, Department of Theoretical Cybernetics chaired by V.A. Yakubovich, in 2001. In 2004 he received Candidate of Science degree (supervisor G.A. Leonov) and in 2016 Doctor of Science degree (Habilitation) from St. Petersburg University. From 2003 Nikolay Kuznetsov has been working in St. Petersburg University and now he is Full professor (tenured) and Head of the Department of Applied Cybernetics there. Since 2018 the research group chaired by Kuznetsov has been awarded the status of the Leading Scientific School (Center of Excellence) of Russia in the field of mathematics and mechanics. In 2020 he was named Professor of the Year in the field of mathematics and physics in Russia.
Since 2018, Kuznetsov is Head of the Laboratory of information and control systems at the Institute for Problems in Mechanical Engineering of the Russian Academy of Science. In 2022, Nikolay Kuznetsov was elected a member of the Russian Academy of Science.
In 2008, Kuznetsov defended his Ph.D. degree at the University of Jyväskylä, Finland (supervisors P. Neittaanmäki, G.A. Leonov).
After the defense, he has been working at the University of Jyväskylä as the Academy of Finland postdoc,
then as a part-time professor at the IT Faculty: from 2014 he is Adjunct Docent and from 2017 – Visiting Professor.
He is co-chair of the Finnish-Russian educational & research program organized in 2007
by the University of Jyväskylä and St. Petersburg University. As a recognition, University of Jyväskylä awarded him a medal for his distinguished merits in the field of applied mathematics and training doctoral students, in 2020 he got the Finnish Information Processing Association (TIVIA) award and was elected a foreign member of the Finnish Academy of Science and Letters (becoming its youngest foreign member at the time of election). In 2021, the joint educational & research program was expanded to include the Lappeenranta-Lahti University of Technology, where Kuznetsov was offered the position of Visiting Professor. The experience of the program he used in 2013 when organizing the first
defenses to the Ph.D. degree granted by St. Petersburg University,
instead of the Candidate of Sciences degrees awarded by the State Supreme Certification Commission.
Scientific work
Kuznetsov’s research interests are in dynamical systems and applied mathematics. In his works, a combination of rigorous analytical and reliable numerical methods allowed for both the advancement in solving previously known fundamental unsolved problems as well as the development of modern engineering technologies. N. Kuznetsov introduced the concept of self-excited and hidden attractors, laying out the foundations for the theory of hidden oscillations. Among his main results are the discovery of a hidden Chua attractor in Chua circuits, revealing of coexisting hidden attractors in electomechanical models with Sommerfeld effect, solutions to the Egan problem on the pull-in range and to the Gardner problem on the lock-in range for phase-locked loops, nonlinear analysis of the CP-PLL and validation of the Gardner conjecture, counterexamples with self-excited and hidden attractors to the classical describing function method,
developed effective analytical-numerical methods for the construction of counterexamples to
the Kalman conjecture on the absolute stability of control systems,
provided justification of time-varying linearization and analysis of
Perron effects of the Lyapunov exponent sign reversal, effective analytical-numerical method for
the finite-time and exact Lyapunov dimension computation, and proof of the Eden conjecture for a number of dynamical systems.
The Web of Science Group proclaimed Kuznetsov a Highly Cited Researcher in Russia twice over two consecutive years (2016-2017) and included him in the worldwide list of Highly Cited Researchers in 2019
(where he was among 3 scientists from St. Petersburg University and the only one from the University of Jyväskylä), 2020, and 2021.
He was awarded the St. Petersburg University Prize in 2020, the Afraimovich Award of NSC society in 2021, and the Andronov Prize of the Russian Academy of Science in 2024 for the theory of hidden oscillations and stability of dynamical systems.
Additional information
N.V. Kuznetsov at Google scholar
N.V. Kuznetsov at Scopus
N.V. Kuznetsov at Web of Science
N.V. Kuznetsov at Mathematics Genealogy Project
World Top Mathematics Scientists
Mathematician Nikolay Kuznetsov at St. Petersburg University. St. Petersburg University News. 10 Jan 2022
Abramovich S., Kuznetsov N., Razov A., G.A. Leonov: eminent scholar, admired teacher and unconventional administrator, Journal of Physics: Conference Series, Vol. 1864, 2021, art. num. 012066.
S. Abramovich, N. Kuznetsov, G. Leonov. V. A. Yakubovich — mathematician, “father of the field”, and herald of intellectual democracy in science and society, IFAC-PapersOnLine, 48(11), 2015, 1–3 (video)
Selected lectures
N.Kuznetsov, Keynote lecture Hidden attractors in science and technologies, General meeting of the Finnish Academy of Science and Letters, Finland, 2021
N.Kuznetsov, Invited lecture The theory of hidden oscillations and stability of dynamical systems, Int. Workshop on Applied Mathematics, Czech Republic, 2021
N. Kuznetsov, Afraimovich award plenary lecture The theory of hidden oscillations and stability of dynamical systems, Int. Conference on Nonlinear Dynamics and Complexity, USA, 2021
Selected publications: books and surveys
References
1979 births
Living people
Saint Petersburg State University alumni
University of Jyväskylä alumni
Chaos theorists
Hidden oscillation
Members of the Finnish Academy of Science and Letters | Nikolay V. Kuznetsov | [
"Mathematics"
] | 1,268 | [
"Hidden oscillation",
"Dynamical systems"
] |
62,777,873 | https://en.wikipedia.org/wiki/TOI-1338 | TOI-1338 is a binary star system located in the constellation Pictor, about 1,320 light-years from Earth. It is orbited by two known circumbinary planets, TOI-1338 b, discovered by the Transiting Exoplanet Survey Satellite (TESS) and BEBOP-1c, discovered by the Binaries Escorted By Orbiting Planets project.
Discovery and nomenclature
The circumbinary planet TOI-1338 b was found in the summer of 2019 by Wolf Cukier, a 17-year-old attending Scarsdale High School in New York at the time, who joined the Goddard Space Flight Center as a summer intern. The acronym TOI stands for "TESS Objects of Interest." Cukier studied data provided by volunteers of the Planet Hunters citizen science project, looking through data that had been flagged as an eclipsing binary. Cukier and six of the Planet Hunter volunteers are co-authors of the publication regarding the planet. Cukier then attended Princeton University as an undergraduate student in the Department of Astrophysical Sciences and graduated in 2024.
The discovery of TOI-1338 b was announced in early January 2020 at the 235th American Astronomical Society meeting in Honolulu, Hawaii. In February 2021, a petition was launched calling for TOI-1338 b to be renamed SOPHIE in honor of late Scottish musician Sophie. The petition was supported by Charli XCX and Caroline Polachek. The petition was unsuccessful in renaming TOI-1338 b, however, the International Astronomical Union announced that the minor planet 1980 RE1 was given the permanent name Sophiexeon in June 2021.
In June 2023, a second circumbinary planet within the system was announced to have been discovered, named BEBOP-1c. It was the first circumbinary planet to be found using the radial velocity method.
Stellar binary
TOI-1338 is a single-lined spectroscopic binary system, consisting of an F8 star and a red dwarf of spectral type M. The system has an age of 4.4 billion years. The two stars with masses of 1.13 and 0.313 revolve around each other every 14.6 days. The red dwarf is about nine magnitudes fainter than the primary star and cannot be detected in the spectrum.
The orbit of the two stars is inclined at 89.7° to the plane of the sky (so edge-on) and both primary and secondary eclipses can be observed, although the brightness changes are very small. The primary eclipse occurs when the hotter primary star is partially occulted by the cooler secondary. It lasts about five hours and the brightness decreases by about 4%. The secondary eclipses occur when the cooler star is occulted by the hotter star. They also last about five hours but the brightness drops by less than half a percent.
Planetary system
The planet TOI-1338 b is between Neptune and Saturn in size, and has an orbit that is within ~1° coplanar with the binary. The most recent and precise estimate of its mass is roughly 11 times that of Earth, indicating a low density similar to that of circumbinary planet Kepler-47c. The spin of the primary star also aligns with the orbits of the binary and the planet (spin-orbit angle β = °). This is the second time the Rossiter–McLaughlin effect was measured for a star hosting a circumbinary planet. Kepler-16 was the first system with such a measurement. The measurement of the alignment for TOI-1338 suggests that the planet formed from a single circumbinary disk.
TOI-1338 c, or BEBOP-1c, is a gas giant about 75 times the mass of Earth. It is also coplanar (or nearly so) with the binary stars and planet b.
See also
TOI-700
TOI-849 b
References
External links
TESS – Official WebSite
NASA Telescope Discovers Its First Planet Orbiting Two Stars
TOI 1338 at ExoFOP TESS
The TOI 1338 subject at Planet Hunters, as mentioned in the paper
Exoplanets discovered by Planet Hunters
Planetary systems with two confirmed planets
1338, TOI
Pictor
Eclipsing binaries
F-type main-sequence stars
M-type main-sequence stars | TOI-1338 | [
"Astronomy"
] | 894 | [
"Pictor",
"Constellations"
] |
62,777,988 | https://en.wikipedia.org/wiki/LC3%20%28codec%29 | LC3 (Low Complexity Communication Codec) is an audio codec specified by the Bluetooth Special Interest Group (SIG) for the LE Audio audio protocol introduced in Bluetooth 5.2. It's developed by Fraunhofer IIS and Ericsson as the successor of the SBC codec.
LC3 provides higher audio quality and better Packet loss concealment than SBC, G.722 and Opus, according to subjective testing by the Bluetooth Special Interest Group and ETSI. The conclusion regarding Opus is disputed as the test only included speech audio, but the comparison was made to version 1.1.4 of the reference Opus encoder, using complexity level 0 at 32 kbps and relying on CELT (general audio) instead of the FEC-capable SILK (speech); the test also did not take into account the newer version 1.2 of the Opus encoder released in 2017, where significant improvements were made to low bitrate streams.
Supported systems:
Android 13; Google's liblc3 codec is open-source as a standalone GitHub project
Windows 11
Zephyr OS
Linux via bluez-alsa or BlueZ + PipeWire
LC3plus
LC3plus High Resolution mode is a codec defined by ETSI and is not compatible with the LC3 defined by Bluetooth SIG. It's included in the 2019 DECT standard.
On November 9, 2022, the Japan Audio Society (JAS) released a statement certifying LC3plus with the "Hi-Res AUDIO WIRELESS" logo. LC3plus is the 4th codec to receive this, alongside SCL6 (formerly known as MQair), LDAC and LHDC codecs.
The ETSI implementation of LC3plus is source-available software, subject to a ETSI Intellectual Property Rights Policy and the usual patent restrictions.
Fraunhofer defines a way to use LC3plus over A2DP.
See also
SBC (codec)
AptX
LDAC (codec)
LHDC (codec)
References
Audio codecs
Bluetooth | LC3 (codec) | [
"Technology"
] | 439 | [
"Wireless networking",
"Bluetooth"
] |
62,778,239 | https://en.wikipedia.org/wiki/Camp%20Sibert | Camp Sibert was a U.S. Army chemical weapons training facility in Etowah, and St. Clair Counties, Alabama, during the World War II era. Covering 32,000 acres, the land for the camp was acquired by the Army in 1942. The site has been redeveloped, including a residential community, but concerns over chemical contamination and unexploded ordnance remain. The camp was named for Major General William L. Sibert, first commander of the Army's Chemical Warfare Service, and coincidentally an Etowah County native.
From September 1942 to March 1945, the camp was commanded by Brigadier General Haig Shekerjian, an Armenian-American graduate of the West Point class of 1911. Private A. Baligian of the U.S. Army visited Camp Sibert and conducted a brief interview with Shekerjian for the June 16, 1943, issue of Hairenik Weekly (later renamed the Armenian Weekly).
Further reading
This is Camp Sibert Alabama "Chemical Warfare Service", 32 pages, including photographs (1944)
Referencesnced
Chemical warfare facilities
1942 establishments in Alabama
Buildings and structures in Etowah County, Alabama
Buildings and structures in St. Clair County, Alabama | Camp Sibert | [
"Chemistry"
] | 245 | [
"Chemical warfare facilities"
] |
62,781,020 | https://en.wikipedia.org/wiki/NearlyFreeSpeech | NearlyFreeSpeech is a privately funded, US-based, low cost web hosting provider and domain name registrar that began in 2002. It was started in response to concerns about the entry of large companies into Internet publishing, and to promote freedom of speech.
History
In September 2006, Jeffrey D. Wheelhouse registered the NearlyFreeSpeech trademark.
Endorsements
By 2008, Michael Hemmingson of San Diego Reader wrote that the Electronic Frontier Foundation suggested using services such as NearlyFreeSpeech.net and Tor software to avoid being fired for blogging. In 2009 Shawn Powers of Linux Journal reviewed Nearly Free Speech and recommended them over GoDaddy even after having some technical issues. In 2010 Jason Fitzpatrick of LifeHacker.com listed Nearly Free Speech as first of "Five Best Personal Web Hosts" and said they were unusual because of their incremental billing based on usage. In a similar 2012 "top five" list by Alan Henry of LifeHacker.com, Nearly Free Speech was given "honorable mention" and he said they offer exceptional hosting plans for as low as $0.25, and promise to only make you pay for what you use.
In 2010 in "Twitter Application Development For Dummies", Dusty Reagan recommended Nearly Free Speech for learning PHP development. In 2010 Cody Fink of MacStories.net, describing how to install Fever in 10 minutes, called Nearly Free Speech, "an amazing hosting solution that's relatively cheap, especially for light use." In 2012 in "Handbook of Research on Didactic Strategies and Technologies for Education" Nearly Free Speech was cited as a "pay as you go" service, which could reduce costs significantly. In 2013, Nearly Free Speech was used for a low-cost promotion involving the posting of indie Zelda-alike game Anodyne on The Pirate Bay.
Controversies
BugMeNot controversy
In 2004 Matt Hines of CNET said Nearly Free Speech supported BugMeNot against take-down attempts. Kevin Newcomb of clickz.com wrote that Texas-based NearlyFreeSpeech.net spokesman Jeff Wheelhouse said, "NearlyFreeSpeech.NET supports and defends the free expression rights of www.bugmenot.com and all our members to the very limit of its terms of service."
BugMeNot's move to the Nearly Free Speech provider, which also hosts a number of highly controversial sites, prompted BugMeNot's creator to say, "Personally, I don't care if I'm sharing a server with neo-Nazis. I might not agree with what they have to say, but the whole thing about freedom of speech is that people are free to speak."
Badger Killers website controversy
In 2012, Kelly Fiveash of The Register said US-based hosting firm Nearly Free Speech resisted UK government attempts to take down the Badger-Killers website, which had personal details of persons deemed to be badger cull supporters, including politicians, farmers and professors.
Alt-right and other controversies
In 2017, Ali Breland of theHill.com described how NearlyFreeSpeech's commitment was tested in the 2012 badger culling website case. She also quoted the CEO of alt-right Twitter alternative Gab, who said that NearlyFreeSpeech might be a "safe haven" for his website after their web host gave them five days to transfer their domain. In 2017 in Media Law, Ethics, and Policy in the Digital Age, NearlyFreeSpeech's policy of not shutting down site services without a court order made them the hosting choice for Crocels News after other services shutdown their services during a defamation dispute. In 2019 in Technical Blogging: Amplify Your Influence, Antonio Cangiano "wholeheartedly" recommended Nearly Free Speech as registrar and webhost for controversial content.
In January 2021, NearlyFreeSpeech published a statement on their response to a surge in business and communications from "racists." The statement was intended to clarify their positions on "free speech," refusal to host illegal content, careful cooperation with law enforcement, and opposition of racism, hatred and bigotry.
References
External links
Employee-owned companies of the United States
Web hosting
File hosting
Domain name registrars
Cloud platforms
Internet properties established in 2002 | NearlyFreeSpeech | [
"Technology"
] | 866 | [
"Cloud platforms",
"Computing platforms"
] |
65,631,074 | https://en.wikipedia.org/wiki/Jamulus | Jamulus is open source (GPL) networked music performance software that enables live rehearsing, jamming and performing with musicians located anywhere on the internet. Jamulus is written by Volker Fischer and contributors using C++. The Software is based on the Qt framework and uses the OPUS audio codec. It was known as "llcon" until 2013.
One of the problems with music playing over the internet in real time is latency - the time lag that occurs while (compressed) audio streams travel to and from each musician. Although the precedence effect means that small delays (up to around 40 ms) can be perceived as synchronous, longer delays make it practically impossible to play live together. A further problem is jitter, a type of packet delay due to changes in latency over time, which results in choppy or distorted sound. Long delays can even lead to packet loss (perceived as a 'blackout'). These can be alleviated by delay buffers or jitter buffers (both of which are present in Jamulus) - but these then add to the overall round-trip delay, so need to be balanced.
Popular video conferencing software such as Zoom or Teams is unsuited to this task as the latency can be much higher (Zoom recommends "a latency of 150ms or less" and jitter of "40ms or less", and in some 2020 tests was shown to have an average latency of 135 ms; the "Audio poor quality metrics" for Teams include having "Round-trip time >500 ms" and "Jitter >30 ms"). In addition, most such software is optimized for speech rather than music, so sustained musical notes can be misidentified as background noise and filtered out (although this can be alleviated to an extent via settings such as "Enable Original Sound"). Conferencing software is also often designed for one person to be heard at a time (the speaker gets 'focus'), to stop people talking over each other, but this makes playing music together impossible. In addition, conferencing software does not normally allow detailed setting of individual audio streams' volume or panning on the user side, both of which are integral features of Jamulus.
To reduce latency as much as possible, Jamulus makes use of compressed audio and the UDP protocol to transmit audio data. Total latency is composed of:
network latency due to delays within the network - every 300km is responsible for at least 1 ms extra latency since the speed of light limits the data transport on internet.
conversion latency - if analog-to-digital conversion or digital-to-analog conversion is not handled by special hardware, these conversions will add additional latency;
audio latency from sound traveling through air, if the microphone and/or loudspeakers are not in immediate proximity. Every meter of distance adds around 3 ms delay due to the limitation of the speed of sound.
Jamulus is client-server based; each client transmits its own compressed audio to a server on the internet. The server mixes the (decompressed) audio stream for each user separately and re-transmits the individual compressed mix to each client. Each client has its own mixing console which controls its mix on the server.
Servers can be either public or private (termed "Registered" and "Unregistered", since Jamulus has no built-in user authentication mechanism), the former being listed by "directories" from which users can choose a server with the lowest latency for them.
Usage
Already in 2018, Jamulus was attracting attention as a way for classical ensembles such as string quartets to rehearse at a distance, but its usage increased dramatically in 2020 due to the COVID-19 pandemic. In April 2020 it was being downloaded two thousand times per day, with the trend increasing. It was elected SourceForge 'Project of the Month' in June 2020. Jamulus Storband, Sweden's first "virtual big band" with over 20 members, also started that month. Many changes were later made to support larger groups, such as choirs with as many as 98 members as well as WorldJam, an initiative allowing musicians from all over the world to play together on a regular basis.
Having a synchronized metronome for participants of a session can be key to helping musicians keep the pace of the song and be in sync with each other. Numerous online metronomes are available, or other OpenSource tools may be used: as one example, Sychronome uses NTP (Network Time Protocol) with a network time server to sync metronomes for each Jamulus client via smartphones.
See also
LoLa
JamKazam
Ninjam / Ninbot
SonoBus
HPSJam
Koord
Comparison of Remote Music Performance Software
References
Audio software
2006 software
Music software
Audio software with JACK support | Jamulus | [
"Engineering"
] | 1,012 | [
"Audio engineering",
"Audio software"
] |
65,634,459 | https://en.wikipedia.org/wiki/Vacuum%20arc%20thruster | A vacuum arc thruster (VAT) is a form of electric spacecraft propulsion. It uses a vacuum arc discharge, across an insulator, between two electrodes to produce thrust. A metal plasma is produced from micrometer-size cathodic spots. Thus, whereas the insulator is used as propellant in a pulsed plasma thruster, in a VAT the metallic cathode is consumed as propellant.
See also
Pulsed plasma thruster
Vacuum arc
References
External links
Ion engines | Vacuum arc thruster | [
"Physics",
"Chemistry",
"Astronomy"
] | 100 | [
"Matter",
"Outer space",
"Ion engines",
"Astronomy stubs",
"Outer space stubs",
"Ions"
] |
65,634,774 | https://en.wikipedia.org/wiki/Allosorus%20pulchellus | Allosorus pulchellus is a species name of a fern, which may refer to:
Allosorus pulchellus (Bory & Willd.) C.Presl, combination made in 1836, now Oeosporangium pulchellum
Allosorus pulchellus M.Martens & Galeotti, described in 1842, an invalid later homonym of the above, now called Argyrochosma formosa
Pteridaceae | Allosorus pulchellus | [
"Biology"
] | 100 | [
"Set index articles on plants",
"Set index articles on organisms",
"Plants"
] |
65,635,219 | https://en.wikipedia.org/wiki/Trioecy | Trioecy , also spelled triecy, is a sexual system characterized by the coexistence of males, females, and hermaphrodites. It has been found in both plants and animals. Like androdioecy and gynodioecy, trioecy is a mixed mating systems.
Terminology
Trioecy is also called tridioecy and subdioecy .
The term trioecy comes from the Neo-Latin word Trioecia, a former order of trioecious plants.
Evolution of trioecy
Trioecy may be an unstable transient state associated with evolutionary transitioning from gynodioecy to dioecy. In brachiopod species, trioecy usually breaks into androdioecy or gynodioecy. Other studies show that trioecious populations originated from gonochoristic ancestors which were invaded by a mutant selfing hermaphrodite, creating a trioecious population. It has been suggested that chromosomal duplication plays an important part in the evolution of trioecy.
But one study found that trioecy can be stable under nucleocytoplasmic sex determination. Another theoretical analysis indicates that trioecy could be evolutionary stable in plant species if a large amount of pollinators vary geographically.
Occurrence
Trioecy is a relatively common sexual system in plants, estimated to occur in about 3.6% of flowering plant species, although most reports of trioecy could be misinterpretations of gynodioecy. It is rare as well as poorly understood in animals.
Species that exhibit trioecy
The following species have been observed to exhibit a trioecious breeding system.
Plants
Buddleja sessiliflora
Buddleja americana
Coccoloba cereifera
Garcinia indica
Fragaria virginiana
Fraxinus excelsior
Fuchsia procumbens
Mercurialis annua
Opuntia robusta
Pachycereus pringlei
Pleodorina starrii
Animals
Aiptasia diaphana
Auanema rhodensis
Auanema freiburgensis
Hydra viridissima
Thor manningi
Semimytilus algosus Pacific mussel
See also
Dioecy
Gynodioecy
Androdioecy
Hermaphrodite
Monoicy
References
Reproductive system
Fertility
Sex
Sexual system | Trioecy | [
"Biology"
] | 489 | [
"Behavior",
"Reproductive system",
"Sex",
"Reproduction",
"Sexual system",
"Organ systems"
] |
65,635,377 | https://en.wikipedia.org/wiki/Seawind%20Ocean%20Technology | Seawind Ocean Technology B.V., a Netherlands based company, is a manufacturer (OEM) of integrated floating wind turbine and green hydrogen systems. Seawind is developing two-bladed floating wind turbines (6.2 MW and 12.2 MW) suitable for installation in all seas, including hurricane regions and ultra-deep waters. Founded on original research and development work by NASA, Hamilton Standard (now United Technologies Corporation/Raytheon Technologies), Enel, and Aeritalia; Seawind's offshore wind power turbines with integrated foundations have been patented, proven at 1.5 MW, and achieved Type D DNV certification in December 2019. The company is now planning the launch of its Seawind 6 demonstrator to be followed by the pre-series Seawind 12, a project earmarked for installation as early as 2024-25 that seeks to obtain DNV's highest certification level.
Overview
Seawind Ocean Technology is developing offshore wind energy solutions that meet the needs of large and small installations to support global decarbonization. Seawind's technology stems from Glidden Doman’s flexible two-bladed turbine system design that is compliant with the forces of nature rather than resistant to them. Seawind's robust design simplicity, which supports higher turbine rotation speeds, achieves lower torque, lower fatigue, a lighter drive train, and a longer life due to the teetering hub technology. The company's teetering hub technology works in conjunction with a yaw power control system that eliminates all blade pitch control mechanisms.
Seawind's floating wind turbines, which allow for increased accessibility through its nacelle helideck, do not require pile driving, cranes, and heavy vessels for installation at sea. Seawind's system design results in a simpler turbine with fewer parts that significantly reduces overall weight. The Seawind 12.2 MW turbine has a 640-ton turbine head weight, which is 210 tons lower than its nearest comparable competitor. This weight disparity substantially increases the power generated per ton, making it a highly efficient turbine. Reducing design complexity and the turbine head weight on top a floating wind turbine system is critical to ensure structural stability and technology optimization.
Seawind calculates the levelized cost of energy (LCOE) for the energy produced by its two-bladed floating wind turbines to be more than 25% lower than state-of-the-art three-bladed offshore wind energy technologies. Seawind states that its projected LCOE advantage will also accelerate the company's target objectives for offshore and onshore green hydrogen production.
History
Helicopter innovations
Evolution of Seawind's floating wind turbine technology can be traced back to World War II when Sikorsky Aircraft (now United Technologies Corporation) hired American engineer Glidden Doman to address helicopter structural and dynamic problems including blade failures. Igor Sikorsky developed and flew the first successful helicopter in the United States during 1939.
Doman's successful efforts for Sikorsky led to the filing of patents and the establishment of Doman Helicopters, Inc., one of America's original six helicopter companies, on August 31, 1945. In 1947, Doman Helicopters purchased a Sikorsky R-6 from the United States Army Air Corps to test its new rotor design and control system, which featured an unorthodox gimbaled rotor head system that eliminated rotor hinges and dampers while including blades of soft-in-plane dynamic design. Doman's initial helicopter, the LZ-1A - a Sikorsky R-6 converted to a Doman rotor and control system, first flew in 1947. The LZ-1A was followed in development by the larger LZ-4 in 1950. Doman Helicopters' crowning achievement was the Doman LZ-5/YH-31 eight-place helicopter, which achieved FAA certification on December 30, 1955. The unique feature of this helicopter was its hinge-less but gimbaled, tilting rotor hub that greatly reduced stress and vibration in the blades and in the whole helicopter.
Doman Helicopters, Inc operated for 25 years by applying its engineering concepts and manufacturing capabilities to a number of applications beyond helicopters. Pilots that have flown Doman's helicopters note the exceptional hovering stability, significant reduction in vibrations, and the ‘finger-tip control’ with which they could fly the machines.
Two-bladed helicopters
Two-bladed, teetering hinge rotor designs have been used extensively in helicopters, most notably in numerous models and many thousands of helicopters built by the Bell Helicopter company. The Bell 47, with its distinctive "soap bubble" cockpit canopy windshield, was used in the Korean War (e.g. MEDEVAC missions, in M*A*S*H series, and one is on display at the Museum of Modern Art in New York) and the Bell 204 was used extensively in the Vietnam War.
Bell's two-bladed rotor with a teetering hinge and Doman Helicopters' four-bladed rotor with a gimbaled hinge, offered similar benefits in reducing stresses in the rotor blades and preventing much of the stress from being transmitted to the fuselage. Glidden Doman believed that the four-bladed rotor was smoother during a helicopter's forward flight, but since wind turbines are not involved in forward flight, the two-bladed wind turbine design offered the same benefits with greater simplicity.
Two of Doman's helicopters, the converted Sikorsky R-6 (Doman LZ-1A) and a Doman LZ-5/YH-31, are on display at the New England Air Museum in Windsor Locks, Connecticut. Glidden Doman was one of the first to transfer knowledge of helicopter rotor dynamics technology to wind turbines.
NASA research and development
In 1973, the Middle East oil embargo escalated interest in wind energy technology development. From 1974 - 1981, the NASA Glenn Research Center, formerly the Lewis Research Center in Cleveland, Ohio, initiated a US wind energy program for the development of utility-scale horizontal-axis wind turbines.
A 1975 National Science Foundation (NSF) contract provided Glidden Doman with funding to explore wind turbine structural dynamics with the objective to eliminate the possibility of wind turbine blade failures due to turbulence. Boeing's MOD-2 with the Doman-conceived flexible design, two-bladed wind turbine with a teeter hinge, became a flagship achievement in this 7-year NASA managed wind energy program for the U.S. Department of Energy and the U.S. Department of the Interior.
Two-bladed wind turbines
Hamilton Standard
In 1978, Glidden Doman was hired by Hamilton Standard (now a United Technologies Corporation company) to design wind turbines. In 1982, Hamilton Standard installed the WTS-4, a 4.2 MW two-bladed wind turbine with a teetering hub, soft steel tower, and pitch power control in Medecine Bow, Wyoming. In 1983, the Karlskronavarvet shipyard installed the WTS-3, a 3 MW two-bladed, downwind design wind turbine in Maglarp, Sweden. The WTS-3 design, which was developed in cooperation with US based Hamilton Standard, also featured a soft steel tower that has become the standard for multi-MW wind turbines.
To this day, the WTS-4 is the most powerful wind turbine to have operated onshore in the US and it held the world record for power output for over 20 years. Toward the end of this project, NASA provided Doman with funding to explore broad range variable speed on the WTS-4. The outcome of Doman's work was a strong patent in his name and the conclusion that such a variable speed system (i.e. the Gamma turbine) should be developed.
After an extensive due diligence review, Enel (Italy's largest utility) and Aeritalia bought a license from United Technologies and moved Doman to Italy where the Gamma 60 technology was designed and demonstrated under Wind Energy Systems Taranto SpA (WEST).
Gamma 60
Gamma, the Italian acronym for WEST's (Wind Energy Systems Taranto SpA) project - “Advanced Multi Megawatt Wind Generator”, began in 1987 and explored all available technology to create a turbine design optimized for economic performance. Gamma's technology is based on Doman's design philosophy of compliance with the forces of nature in its flexible tower, teetered hub, low-modulus blade material, and broad-range variable-speed power train rather than resistance to these forces which is prevalent in 3-bladed Danish turbine designs.
Doman's work was further inspired by German aerospace engineer Kurt Hohenemser who declared that wind turbines should be two-bladed, fixed pitch, and controlled by yawing to achieve the highest reliability. Dr. Hohenemser, along with his mentor Anton Flettner, developed helicopters for the U.S. military after being among the first German immigrants in the United States after World War II.
The 1.5 MW Gamma 60 horizontal-axis wind turbine began operations at Alta Nurra, Sardinia, Italy in 1992. Power from the Gamma 60 turbine is controlled by yawing the rotor, a maneuver made possible by the load alleviation resulting from the soft-system design. Features including the teeter hinge that eliminate major vibratory loading, allow a Gamma system to be very lightweight and longer lived than its competitors. Broad range variable speed allows the Gamma 60 wind turbine to operate at rotational speeds proportional to the wind speed. This allows the Gamma turbine to be very quiet when the wind is moderate and to run faster under high wind conditions. The Gamma 60 wind turbine operated successfully in Sardinia, Italy from 1992 – 1997.
Doman successfully replicated the benefits associated with the four-bladed helicopter rotor with a gimbal hinge, while also recognizing advantages inherent in two-bladed helicopter rotors, in the development of the Gamma 60 two-bladed rotor with a teetering hinge. The Gamma 60 was the world's first variable speed wind turbine with a teeter hinge.
In 1997, Italian nuclear mechanical engineer Silvestro Caruso, who was assigned by Finmeccanica (now Leonardo S.p.A.) for an independent review of the Gamma 60 turbine, concludes that Gamma technology has great potential. Commercialization of the Gamma 60 prototype was planned, including a conditional investment for 10 Gamma turbines by a US utility, but legal disputes and contractual claims between WEST and Enel, the privatization of Enel, and tumbling oil prices in 1998 resulted in the program's cancellation. These factors created the opportunity for Doman, Caruso, and the other shareholders to launch a new company. In 2004, Gamma Ventures, Inc was formed by Glidden Doman and Silvestro Caruso after the company acquired two yet to be completed 2 MW Gamma turbines and the technology rights from the successful Italian Gamma venture.
Floating wind turbines
In 2004, Martin Jakubowski founded Blue H Technologies B.V. to develop floating wind turbines. Sky Saver Srl, the Italian subsidiary of Blue H Technologies, files for a grant and permission to install a two-bladed wind turbine on a floating tension-leg platform (TLP) off the coast of Southern Italy in the Strait of Otranto.
In December 2007, Blue H Technologies deployed the world's first floating wind turbine, 21.3 kilometers (13.2 miles) off the coast of Apulia, Italy. The prototype was installed in waters 113 meters (371 ft) deep in order to gather test data on wind and sea conditions, and was decommissioned at the end of 2008. The turbine utilized a tension-leg platform design and a two-bladed turbine.
In 2007, Blue H Technologies acquired the Gamma 60 turbine and manufacturing rights from Gamma Ventures, Inc.
In January 2009, the Energy Technologies Institute (ETI) invested £3.3m in Project Deep Water to examine the economic and technical feasibility of a tension-leg platform design using a two-bladed teeter hinge 5 MW floating wind turbine with hybrid concrete/steel floater and concrete counter weight. This project, which was led by Blue Technologies, included BAE Systems, Romax, CEFAS, EDF Energy, PAFA Consulting Engineers and Sea & Land Power, and Energy Ltd. Project Deep Water determined that two-bladed teetered turbines with tension-leg platforms could help reduce the costs of offshore wind in the UK and helped shape the next stage of ETI's Offshore Wind program.
In May 2010, Blue H USA LLC, the US affiliate of Blue H Technologies B.V., secured the first permit in North America for a full-scale floating deep water offshore wind energy platform (United States Army Corps of Engineers Permit Number: NAE-2007-02626).
In 2010, Blue H Technologies shareholders decline funding for additional development of the two-bladed floating offshore wind turbine. Martin Jakubowski and Silvestro Caruso, with support from Gamma Ventures, Inc, establish Condor Wind Energy Ltd after acquiring all relevant assets from Blue H to further develop its proprietary two-bladed teetering hinge offshore wind energy technology.
In 2014, Condor Wind Energy Ltd operations decline after internal differences.
Seawind Ocean Technology corporate structure
In 2014, Martin Jakubowski and Silvestro Caruso established Seawind Ocean Technology B.V. in The Netherlands. In 2015, Seawind Ocean Technology signed an agreement to buy back all assets of Condor Wind Energy Ltd, including most importantly, all technological and intellectual property. In 2017, all shareholders of Gamma Ventures, Inc became shareholders of Seawind Ocean Technology Holding B.V.
In 2019, Seawind Ocean Technology Ltd was created in the UK to develop a British legal entity to support the growing offshore wind industry in UK waters.
In December 2019, Seawind's 6.2 MW and 12.2 MW two-bladed floating wind turbines receive ‘Technology Qualification’ status from DNV GL. DNV GL has agreed to an accelerated schedule resulting in Type A certification for the Seawind 6.2 MW wind turbine in 2025 and the Seawind 12.2 MW turbine in 2026.
Seawind Ocean Technology offshore wind turbines
Seawind 6-126
The Seawind 6-126 wind turbine is a lightweight offshore two-bladed upwind configuration with a teeter hub and active yaw control. Its nacelle is reinforced with rafters, like a ship's hull, and is linked to a central circular-shape helicopter landing deck that can accommodate large twin-engine-helicopters. Seawind's two-bladed teeter hub, which rigidly attaches the two blades to a flexible structure with limited pivoting capability, provides stability and reduces overall system fatigue.
Seawind's teetering hinge introduces an additional degree of freedom to the running rotor (blades and hub). This degree of freedom, decoupling the rotor from the drivetrain, greatly reduces the aerodynamic cyclic loads transferred by the rotor to the drivetrain and greatly reduces the torque necessary to yaw the nacelle around the tower axis. Therefore, Seawind's turbine design can eliminate all blade pitch control mechanisms with its yaw power control system.
Target markets for the Seawind 6-126 include hurricane-prone regions and remote islands.
Seawind 12-225
The Seawind 12-225 wind turbine is a lightweight offshore two-bladed upwind configuration with a teeter hub and active yaw control that has a turbine head mass 203 tons lower than its nearest comparable competitor. Power converters, MV-transformers, and switchgears for the Seawind 6-126 and Seawind 12-225 offshore wind turbines are placed inside the integrated support structure base below water level. This design supports service accessibility, passive seawater cooling, reduces vibration-related power electronics risks, and decreases nacelle mass. The Seawind 12-225 and Seawind 6-126 offshore wind turbine sister models were developed for a design life of more than 25 years.
Seawind's two-bladed offshore wind turbine with teetering hinge is designed to survive hurricane conditions. In the case of extreme wind speeds, Seawind's two-bladed rotor can be positioned horizontally with the blades aligned with the direction of the wind. This configuration, with the flexibility provided by the elastic hinge, is effective to reduce the wind loads on the blades and other components. In extreme wind conditions, the loads are only slightly higher than the maximum loads in normal operations.
Target markets for the Seawind 12-225 include high-wind projects in Europe and the US.
Offshore wind turbine specifications
(*) At rated power
See also
Glidden Doman
Gamma 60 wind turbine
NASA wind turbines
Floating wind turbine
Anton Flettner
Kurt Hohenemser
Variable speed wind turbine
Offshore wind power
References
Wind turbine manufacturers
Dutch companies established in 2014
Renewable resource companies established in 2014
Floating wind turbines
Wind power companies | Seawind Ocean Technology | [
"Engineering"
] | 3,446 | [
"Floating wind turbines",
"Offshore engineering"
] |
65,635,504 | https://en.wikipedia.org/wiki/Kenmotsu%20manifold | In the mathematical field of differential geometry, a Kenmotsu manifold is an almost-contact manifold endowed with a certain kind of Riemannian metric. They are named after the Japanese mathematician Katsuei Kenmotsu.
Definitions
Let be an almost-contact manifold. One says that a Riemannian metric on is adapted to the almost-contact structure if:
That is to say that, relative to the vector has length one and is orthogonal to furthermore the restriction of to is a Hermitian metric relative to the almost-complex structure One says that is an almost-contact metric manifold.
An almost-contact metric manifold is said to be a Kenmotsu manifold if
References
Sources
Differential geometry
Riemannian geometry
Riemannian manifolds
Smooth manifolds | Kenmotsu manifold | [
"Mathematics"
] | 151 | [
"Riemannian manifolds",
"Space (mathematics)",
"Metric spaces"
] |
65,635,605 | https://en.wikipedia.org/wiki/Way%20%28machine%20tool%20element%29 | A way (sometimes known as a slideway, guideway, or bedway) is a type of linear bearing, specifically a linear plain bearing, in a machine tool. It facilitates precise linear motion along a given axis. A way is ground, scraped, or (less often) molded to be very flat, and ways often come in pairs to ensure a flat plane for the carriage or sliding element (slide) to move along smoothly. Ways are usually lubricated with way oil (a kind of machine oil specially made to adhere to the ways while vertical).
Ways have been used since the 19th century and are a critical part of manufacturing processes, especially those requiring low tolerances such as machining. They have been made of various materials over the years, ranging from wood to cast iron, and nowadays including plastic alloys and special polymer materials. They are crafted with painstaking precision, usually being scraped into near total flatness with hand tools. This flatness is required to both provide good results in the manufactured parts, as well as prevent the stick-slip phenomenon (jerking motion due to friction at low speeds). In recent years they have started to be phased out by rolling-element bearings ("ball" bearings), or are forgone entirely in some CNC machines.
Materials
The material the way is made from has differed and evolved since their invention.
Though ways have also been made from wood, the most common material for ways is cast iron, which provides a rigid and durable base for the ways to be formed on. Ways made from cast iron usually have to be scraped into the final dimensions by hand, which is a long and laborious process.
In the late 20th century, composite materials have started to come into use, such as the plastics Turcite and Rulon. These materials are applied to the ways in strips with adhesive, acting as a sacrificial surface that wears instead of the iron, while keeping the same degree of flatness. The composite materials help to reduce friction between the way and the slide, further reducing maintenance costs and downtime.
Geometry
The geometry of the way can vary depending on the situation. The most common types are flat, vee, and dovetail ways.
Flat ways are used when there is little requirement for the slide to be constrained perpendicular to the axis of movement, or the constraint is being provided by another component or otherwise not needed, such as on the carriage of a lathe.
Vee (V-shaped) ways provide constraint to the perpendicular horizontal axis, but do little to prevent the slide from being lifted vertically.
Dovetail ways provide constraint in both perpendicular axes, and are usually used when the slide is lifted vertically along the ways and must be prevented from falling off. This type usually has an adjustable tightness to the way using a gib-strip (a metal piece placed on one side of a dovetail to tighten the fit).
The precise and accurate geometry of the ways (that is, their shape, size, and flatness) is produced via any combination of milling (for roughing and semifinishing), grinding (for any stage up through finishing), lapping (in some cases, for final finishing), or hand scraping (in many cases but not all), with comparison against surface plates as reference standards for the flatness, as well as any other similar reference standards (e.g., precision cylindrical standards or rings) if concave or convex cylindrical ways are needed.
Features
The ways are often fitted with additional features to decrease wear and ease maintenance.
The way is lubricated with way oil, which is specially formulated to reduce friction, but has an additive that makes it adhere to the ways, even vertically. The oil is applied to the ways with either grease fittings, or is sometimes continuously pumped through ducts machined into the face of the ways. The latter was commonly used on shapers, where the entire way is covered by some part of the sliding element at all times. The ends of the ways are fitted with felt wipers to prevent oil from leaking out as the slide overhangs the ways.
Protective guards are sometimes fitted to prevent metal shavings or dropped objects from damaging the ways.
See also
Linear-motion bearing
Plain bearing
References
External links
https://www.aetnaplastics.com/products/d/Turcite
Machine tools | Way (machine tool element) | [
"Engineering"
] | 890 | [
"Machine tools",
"Industrial machinery"
] |
65,635,767 | https://en.wikipedia.org/wiki/Microwave%20electrothermal%20thruster | Microwave electrothermal thruster, also known as MET, is a propulsion device that converts microwave energy (a type of electromagnetic radiation) into thermal (or heat) energy. These thrusters are predominantly used in spacecraft propulsion, more specifically to adjust the spacecraft’s position and orbit. A MET sustains and ignites a plasma in a propellant gas. This creates a heated propellant gas which in turn changes into thrust due to the expansion of the gas going through the nozzle. A MET’s heating feature is like one of an arc-jet (another propulsion device); however, due to the free-floating plasma, there are no problems with the erosion of metal electrodes, and therefore the MET is more efficient.
Mechanism description
The MET contains key features and parts that contribute to its efficiency. The parts include: two endplates (nozzle and antenna), plasma, and a dielectric separation plate.
The resonant cavity is the round overlapping section waveguide that is shorted by the two endplates. The cavity is near the separation plate. There are two end plates inside the MET: the nozzle and the antenna. The nozzle’s function is to convert the gaseous plasma into thrust. The antenna is used to input the microwave power. Although most of the power is absorbed by the plasma, some of it is reflected. Another part of the MET is the plasma. In some cases, plasma is also referred to as the fourth state of matter. The plasma is the main portion of the MET. It is created inside of the system by heating the propellant and is exhausted to generate thrust. The last part of the MET is the dielectric separation plate. This piece of the MET allows both parts of the cavity to be controlled at various pressures.
Principle of operation
Description
In order for the MET to create thrust, it must go through a 4 step process of converting electrical energy into heat energy.
The propellant gas is first injected tangentially into the MET through the nozzle, which allows the plasma to form.
By doing so tangentially, there will be a vortex flow (circular flow) in the system, which creates a cool environment for the plasma to be stabilized.
In order for the plasma to ignite at low levels of electromagnetic power to create thrust, it must be at a low pressure; however, if the plasma has already been ignited, it will be able to survive in the high pressures.
The free-flowing plasma is heated and released through the nozzle, thereby creating thrust.
During this process, the antenna section is held at atmospheric pressure to ensure that there is no plasma formation close to the antenna. It also ensures that the separation plates are not held at two significantly different pressures, which would put stress upon the two plates.
The physical process for what takes place on a molecular level can also be explained in the following manner:
The microwave electrical field causes the electrons to speed up, which then causes them to have collisions with the molecules and atoms inside the plasma.
Through the collisions, there is a transfer of energy to the atoms and molecules in the plasma.
The energy is then converted into heat energy by having inelastic collisions.
Mathematically
Thrust
Thrust is the force that is applied on the rocket caused by when the propellant is released. The formula for thrust is given as:
Where thrust is given as in Newtons(N), as mass flow rate in kilograms/second(kg/s), as exhaust velocity in meters/second(m/s), as exit pressure, as atmospheric pressure, and as nozzle exit area in meters^2(m^2).
Specific impulse
Specific impulse is how efficiently the fuel of the MET is used to create thrust. The formula for specific impulse is given as:
Where is given as specific impulse, as thrust in N, as mass flow rate in kg/s, and as the gravitational acceleration of the earth.
Mass relationship
When applying the conservation of momentum law, the relationship between mass of propellant and initial mass of the spacecraft can be shown as:
Where is given as propellant mass, as initial spacecraft mass, as change in velocity, is as specific impulse, and as earth’s gravity.
Application
Space
The MET’s main purpose is spacecraft propulsion. The energy that is created is meant to be converted into kinetic energy, which will produce thrust in space. Some tasks include orbit raising and stationkeeping. Orbit raising is changing the orbit of a ship using propulsion systems, while stationkeeping is maintaining a spacecraft’s position in relation to other spacecraft. This includes the maintenance of satellites at certain positions.
Developments
Control system
In August 2020, a control system based on the MET was devised. When the MET changes the energy from electromagnetic waves to propellant, it allows for the small impulses of the MET to provide autonomous control over the satellite.
In-space electrothermal propulsion
The MET was adapted for in-space electrothermal propulsion. In order to control the altitude of a satellite/spacecraft and for primary propulsion, the tunable frequency MET was provided. Instead of a magnetron (microwave generating device), there were alternative constructional features which included using generators and semiconductors. This made it more efficient allowing the thruster to operate at two separate frequencies.
Pros and cons
Pros
Relative to other electrothermal thrusters, the MET ranks higher than resistojets and some claim that they may be able to achieve similar performance to arc-jets. This is based on the supposition that the MET provides higher specific impulse, or in simpler terms more thrust for the amount of fuel. Another advantage is that because microwaves can be collected and fed directly into the thrust chamber, the MET is extremely compatible with space transport. Finally, the MET can be run on water vapor as a propellant, which is abundant throughout the cosmos.
Cons
In general, electrothermal thrusters have the lowest efficiency among most other electric propulsion systems. MET ranks lower than most electrostatic thrusters such as ion thrusters. Another disadvantage is that the MET has relatively low thrust compared to chemical rocket engines (although this is true for electric propulsion in general).
References
Ion engines | Microwave electrothermal thruster | [
"Physics",
"Chemistry",
"Astronomy"
] | 1,250 | [
"Matter",
"Outer space",
"Ion engines",
"Astronomy stubs",
"Outer space stubs",
"Ions"
] |
65,636,147 | https://en.wikipedia.org/wiki/House%20%26%20Home | House & Home magazine (also known as Canadian House & Home magazine) is a decorating, design and lifestyle publication that is published by the Toronto-based company House & Home Media.
The publication's title has a long history that goes back as far as 1952, although the magazine's current ownership, direction and subject matter commenced in 1986, when the publication was purchased by publisher Lynda Reeves and re-launched as the eponymous publication of the House & Home brand.
House & Home, The Magazine of Building (also styled House + Home) was originally a monthly architecture magazine published by Time Inc. from 1952 to 1964. The first issue was an offshoot of Architectural Forum and sent to 100,000 subscribers. The original editor and publisher was P.I. Prentice, and Douglas Haskell was editorial chairman. The illustrated monthly carried feature articles on home building, planning, and building materials. The magazine was sold to McGraw-Hill in 1964 and renamed Housing in 1978. That magazine merged with Builder magazine in 1982. Toronto, Canada - based interior designer Lynda Reeves purchased the magazine in 1986 and resurrected the original name. The magazine has a French language counterpart called Maison & Demeure.
House & Home is a registered trademark in Canada and the US, and has been used by House & Home Media on branded merchandise sold across Canada at the Bay, Home Outfitters and Zellers stores. The House & Home: Style for Living branded merchandise is currently sold across Canada at The TJX Companies Inc. stores such as Winners, Homesense and Marshalls. The House & Home brand has given rise to a website, Houseandhome.com, a retail shopping website, Shophouseandhome.com, and a television series, House & Home with Lynda Reeves, which was broadcast on CTV and GlobalTV before being distributed internationally.
References
Architecture magazines
Magazines established in 1952
Magazines disestablished in 1982
Magazines established in 1986 | House & Home | [
"Engineering"
] | 395 | [
"Architecture stubs",
"Architecture"
] |
65,636,614 | https://en.wikipedia.org/wiki/General%20Association%20of%20Engineers%20of%20Romania | The General Association of Engineers of Romania () is a non-governmental professional organization of engineers in Romania, with the objectives of promoting industrial culture and supporting the professional activity of engineers by highlighting achievements.
History
Professional associations of engineers were established in Romania as early as the 19th century, when in 1876 the Society of Engineers and Architects was created, but the first viable association was the Polytechnic Society, established in 1881 on the occasion of the inauguration of the Buzău-Mărășești railway, the first railway in Romania designed and executed by Romanian engineers. The first president of the Polytechnic Society was Ștefan Fălcoianu, honorary president being Dimitrie Sturdza. Subsequently, among the presidents of the society were personalities such as Anghel Saligny and Elie Radu.
In 1918, the General Association of Engineers of Romania was established in Iași. The stated aim was to "organizse and increase the knowledge and working power of engineers (...), in order to make the most use in the work of restoring the country (...), solidarity and support for their professional interests". The first president of AGIR was Gheorghe Balș,and one of the next was Nicolae Vasilescu-Karpen.
In 1949 the two associations merged under the name of the Scientific Association of Technicians (AST), president being the academic Nicolae Profiri, who at that time was the president of both the Polytechnic Society and AGIR. The name of the association was changed from 1951 to 1962 to the Scientific Association of Engineers and Technicians (ASIT), and from 1962 to 1989 to the National Council of Engineers and Technicians (CNIT).
In 1990 the association resumed its name as the "General Association of Engineers of Romania".
Over the years, engineering associations have been supported by personalities such as Spiru Haret, Ion I. C. Brătianu, Vintilă I.C. Brătianu, Constantin F. Robescu, Traian Lalescu, Gheorghe Țițeica, Nicolae Zane, and George Nestor.
Current Activity
The General Association of Engineers of Romania is registered in the European Commission's database as a potential partner in projects covering the engineering and educational fields. It has a library with 22,000 titles, including The Encyclopædia Britannica, the Romanian Technical Lexicon. It has the following publications:
Univers ingineresc newspaper, bimonthly information publication.
Buletinul A.G.I.R., quarterly edited by the AGIR Publishing House, containing works presented from various scientific events.
The A.G.I.R. Year,c.R.,containing material about aGIR-related events.
Symposia
Scientific Symposium of Romanian Engineers Everywhere
The Scientific Symposium of Romanian Engineers of Everywhere (SINGRO) is a scientific communication session organized every two years, with the aim of facilitating the exchange of experience between Romanian engineers in the world, without excluding other people with compatible concerns.
The 12th session of SINGRO, having the theme "Solutions for an intelligent city”, was organized in Craiova, on September 8-9 2016, in cooperation with the University of Craiova. Engineers from Romania, the Republic of Moldova, France, Switzerland and Bulgaria took part.
AGIR Awards
The General Association of Engineers of Romania recognizes meritorious activity in engineering by the following awaerds:
The AGIR prize, established in 1995, awarded every year on September 14, on the "day of the engineer”, for works of high technical and scientific level.
The Excellence Prize Medal awarded to persons having substantial contributions to the development of the association.
The AGIR Medal, awarded to persons with exceptional activity within the association or in the field of engineering.
References
External links
Civil engineering professional associations
Organizations established in 1918
1918 establishments in Romania | General Association of Engineers of Romania | [
"Engineering"
] | 785 | [
"Civil engineering professional associations",
"Civil engineering organizations"
] |
65,639,408 | https://en.wikipedia.org/wiki/Manifold%20injection | Manifold injection is a mixture formation system for internal combustion engines with external mixture formation. It is commonly used in engines with spark ignition that use petrol as fuel, such as the Otto engine, and the Wankel engine. In a manifold-injected engine, the fuel is injected into the intake manifold, where it begins forming a combustible air-fuel mixture with the air. As soon as the intake valve opens, the piston starts sucking in the still forming mixture. Usually, this mixture is relatively homogeneous, and, at least in production engines for passenger cars, approximately stoichiometric; this means that there is an even distribution of fuel and air across the combustion chamber, and enough, but not more air present than what is required for the fuel's complete combustion. The injection timing and measuring of the fuel amount can be controlled either mechanically (by a fuel distributor), or electronically (by an engine control unit). Since the 1970s and 1980s, manifold injection has been replacing carburettors in passenger cars. However, since the late 1990s, car manufacturers have started using petrol direct injection, which caused a decline in manifold injection installation in newly produced cars.
There are two different types of manifold injection:
the multi-point injection (MPI) system, also known as port injection, or dry manifold system
and the single-point injection (SPI) system, also known as throttle-body injection (TBI), central fuel injection (CFI), electronic gasoline injection (EGI), and wet manifold system
In this article, the terms multi-point injection (MPI), and single-point injection (SPI) are used. In an MPI system, there is one fuel injector per cylinder, installed very close to the intake valve(s). In an SPI system, there is only a single fuel injector, usually installed right behind the throttle valve. Modern manifold injection systems are usually MPI systems; SPI systems are now considered obsolete.
Description
In a manifold injected engine, the fuel is injected with relatively low pressure (70...1470 kPa) into the intake manifold to form a fine fuel vapour. This vapour can then form a combustible mixture with the air, and the mixture is sucked into the cylinder by the piston during the intake stroke. Otto engines use a technique called quantity control for setting the desired engine torque, which means that the amount of mixture sucked into the engine determines the amount of torque produced. For controlling the amount of mixture, a throttle valve is used, which is why quantity control is also called intake air throttling. Intake air throttling changes the amount of air sucked into the engine, which means that if a stoichiometric () air-fuel mixture is desired, the amount of injected fuel has to be changed along with the intake air throttling. To do so, manifold injection systems have at least one way to measure the amount of air that is currently being sucked into the engine. In mechanically controlled systems with a fuel distributor, a vacuum-driven piston directly connected to the control rack is used, whereas electronically controlled manifold injection systems typically use an airflow sensor, and a lambda sensor. Only electronically controlled systems can form the stoichiometric air-fuel mixture precisely enough for a three-way catalyst to work sufficiently, which is why mechanically controlled manifold injection systems such as the Bosch K-Jetronic are now considered obsolete.
Main types
Single-point injection
As the name implies, a single-point injected (SPI) engine only has a single fuel injector. It is usually installed right behind the throttle valve in the throttle body. Single-point injection was a relatively low-cost way for automakers to reduce exhaust emissions to comply with tightening regulations while providing better "driveability" (easy starting, smooth running, freedom from hesitation) than could be obtained with a carburetor. Many of the carburetor's supporting components - such as the air cleaner, intake manifold, and fuel line routing - could be used with few or no changes. This postponed the redesign and tooling costs of these components. However, single-point injection does not allow forming very precise mixtures required for modern emission regulations, and is thus deemed an obsolete technology in passenger cars. Single-point injection was used extensively on American-made passenger cars and light trucks during 1980–1995, and in some European cars in the early and mid-1990s.
Single-point injection has been a known technology since the 1960s, but has long been considered inferior to carburettors, because it requires an injection pump, and is thus more complicated. Only with the availability of inexpensive digital engine control units (ECUs) in the 1980s did single-point injection become a reasonable option for passenger cars. Usually, intermittently injecting, low injection pressure (70...100 kPa) systems were used that allowed the use of low-cost electric fuel injection pumps. A very common single-point injection system used in many passenger cars is the Bosch Mono-Jetronic, which German motor journalist Olaf von Fersen considers a "combination of fuel injection and carburettor".
The system was called Throttle-body Injection or Digital Fuel Injection by General Motors, Central Fuel Injection by Ford, PGM-CARB by Honda, and EGI by Mazda).
Multi-point injection
In a multi-point injected engine, every cylinder has its own fuel injector, and the fuel injectors are usually installed in close proximity to the intake valve(s). Thus, the injectors inject the fuel through the open intake valve into the cylinder, which should not be confused with direct injection. Certain multi-point injection systems also use tubes with poppet valves fed by a central injector instead of individual injectors. Typically though, a multi-point injected engine has one fuel injector per cylinder, an electric fuel pump, a fuel distributor, an airflow sensor, and, in modern engines, an engine control unit. The temperatures near the intake valve(s) are rather high, the intake stroke causes intake air swirl, and there is much time for the air-fuel mixture to form. Therefore, the fuel does not require much atomisation. The atomisation quality is relative to the injection pressure, which means that a relatively low injection pressure (compared with direct injection) is sufficient for multi-point injected engines. A low injection pressure results in a low relative air-fuel velocity, which causes large, and slowly vapourising fuel droplets. Therefore, the injection timing has to be precise to minimise unburnt fuel (and thus HC emissions). Because of this, continuously injecting systems such as the Bosch K-Jetronic are obsolete. Modern multi-point injection systems use electronically controlled intermittent injection instead.
From 1992 to 1996 General Motors implemented a system called Central Port Injection or Central Port Fuel Injection. The system uses tubes with poppet valves from a central injector to spray fuel at each intake port rather than the central throttle body. Fuel pressure is similar to a single-point injection system. CPFI (used from 1992 to 1995) is a batch-fire system, while CSFI (from 1996) is a sequential system.
Injection controlling mechanism
In manifold injected engines, there are three main methods of metering the fuel, and controlling the injection timing.
Mechanical controlling
In early manifold injected engines with fully mechanical injection systems, a gear-, chain- or belt-driven injection pump with a mechanic "analogue" engine map was used. This allowed injecting fuel intermittently, and relatively precisely. Typically, such injection pumps have a three-dimensional cam that depicts the engine map. Depending on the throttle position, the three-dimensional cam is moved axially on its shaft. A roller-type pick-up mechanism that is directly connected to the injection pump control rack rides on the three-dimensional cam. Depending upon the three-dimensional cam's position, it pushes in or out the camshaft-actuated injection pump plungers, which controls both the amount of injected fuel, and the injection timing. The injection plungers both create the injection pressure, and act as the fuel distributors. Usually, there is an additional adjustment rod that is connected to a barometric cell, and a cooling water thermometer, so that the fuel mass can be corrected according to air pressure, and water temperature. Kugelfischer injection systems also have a mechanical centrifugal crankshaft speed sensor. Multi-point injected systems with mechanical controlling were used until the 1970s.
No injection-timing controlling
In systems without injection-timing controlling, the fuel is injected continuously, thus, no injection timing is required. The biggest disadvantage of such systems is that the fuel is also injected when the intake valves are closed, but such systems are much simpler and less expensive than mechanical injection systems with engine maps on three-dimensional cams. Only the amount of injected fuel has to be determined, which can be done very easily with a rather simple fuel distributor that is controlled by an intake manifold vacuum-driven airflow sensor. The fuel distributor does not have to create any injection pressure, because the fuel pump already provides pressure sufficient for injection (up to 500 kPa). Therefore, such systems are called "unpowered", and do not need to be driven by a chain or belt, unlike systems with mechanical injection pumps. Also, an engine control unit is not required. "Unpowered" multi-point injection systems without injection-timing controlling such as the Bosch K-Jetronic were commonly used from the mid-1970s until the early 1990s in passenger cars, although examples had existed earlier, such as the Rochester Ramjet offered on high-performance versions of the Chevrolet small-block engine from 1957 to 1965.
Electronic control unit
Engines with manifold injection, and an electronic engine control unit are often referred to as engines with electronic fuel injection (EFI). Typically, EFI engines have an engine map built into discrete electronic components, such as read-only memory. This is both more reliable and more precise than a three-dimensional cam. The engine control circuitry uses the engine map, as well as airflow, throttle valve, crankshaft speed, and intake air temperature sensor data to determine both the amount of injected fuel, and the injection timing. Usually, such systems have a single, pressurised fuel rail, and injection valves that open according to an electric signal sent from the engine control circuitry. The circuitry can either be fully analogue, or digital. Analogue systems such as the Bendix Electrojector were niche systems, and used from the late 1950s until the early 1970s; digital circuitry became available in the late 1970s, and has been used in electronic engine control systems since. One of the first widespread digital engine control units was the Bosch Motronic.
Air mass determination
In order to mix air and fuel correctly so a proper air-fuel mixture is formed, the injection control system needs to know how much air is sucked into the engine, so it can determine how much fuel has to be injected accordingly. In modern systems, an air-mass meter that is built into the throttle body meters the air mass, and sends a signal to the engine control unit, so it can calculate the correct fuel mass. Alternatively, a manifold vacuum sensor can be used. The manifold vacuum sensor signal, the throttle position, and the crankshaft speed can then be used by the engine control unit to calculate the correct amount of fuel. In modern engines, a combination of all these systems is used. Mechanical injection controlling systems as well as unpowered systems typically only have an intake manifold vacuum sensor (a membrane or a sensor plate) that is mechanically connected to the injection pump rack or fuel distributor.
Injection operation modes
Manifold injected engines can use either continuous or intermittent injection. In a continuously injecting system, the fuel is injected continuously, thus, there are no operating modes. In intermittently injecting systems however, there are usually four different operating modes.
Simultaneous injection
In a simultaneously intermittently injecting system, there is one single, fixed injection timing for all cylinders. Therefore, the injection timing is ideal only for some cylinders; there is always at least one cylinder that has its fuel injected against the closed intake valve(s). This causes fuel evaporation times that are different for each cylinder.
Group injection
Systems with intermittent group injection work similarly to the simultaneously injection systems mentioned earlier, except that they have two or more groups of simultaneously injecting fuel injectors. Typically, a group consists of two fuel injectors. In an engine with two groups of fuel injectors, there is an injection every half crankshaft rotation, so that at least in some areas of the engine map no fuel is injected against a closed intake valve. This is an improvement over a simultaneously injecting system. However, the fuel evaporation times are still different for each cylinder.
Sequential injection
In a sequentially injecting system, each fuel injector has a fixed, correctly set, injection timing that is in sync with the spark plug firing order, and the intake valve opening. This way, no more fuel is injected against closed intake valves.
Cylinder-specific injection
Cylinder-specific injection means that there are no limitations to the injection timing. The injection control system can set the injection timing for each cylinder individually, and there is no fixed synchronisation between each cylinder's injector. This allows the injection control unit to inject the fuel not only according to firing order, and intake valve opening intervals, but it also allows it to correct cylinder charge irregularities. This system's disadvantage is that it requires cylinder-specific air-mass determination, which makes it more complicated than a sequentially injecting system.
History
The first manifold injection system was designed by Johannes Spiel at Hallesche Maschinenfabrik. Deutz started series production of stationary four-stroke engines with manifold injection in 1898. Grade built the first two-stroke engine with manifold injection in 1906; the first manifold injected series production four-stroke aircraft engines were built by Wright and Antoinette the same year (Antoinette 8V). In 1912, Bosch equipped a watercraft engine with a makeshift injection pump built from an oil pump, but this system did not prove to be reliable. In the 1920s, they attempted to use a Diesel engine injection pump in a petrol-fuelled Otto engine. However, they were not successful. In 1930 Moto Guzzi built the first manifold injected Otto engine for motorcycles, which eventually was the first land vehicle engine with manifold injection. From the 1930s until the 1950s, manifold injections systems were not used in passenger cars, despite the fact that such systems existed. This was because the carburettor proved to be a simpler and less expensive, yet sufficient mixture formation system that did not need replacing yet.
In ca. 1950, Daimler-Benz started development of a petrol direct injection system for their Mercedes-Benz sports cars. For passenger cars however, a manifold injection system was deemed more feasible. Eventually, the Mercedes-Benz W 128, W 113, W 189, and W 112 passenger cars were equipped with manifold injected Otto engines.
From 1951 until 1956, FAG Kugelfischer Georg Schäfer & Co. developed the mechanical Kugelfischer injection system. It was used in many passenger cars, such as the Peugeot 404 (1962), Lancia Flavia iniezione (1965), BMW E10 (1969), Ford Capri RS 2600 (1970), BMW E12 (1973), BMW E20 (1973), and the BMW E26 (1978).
In 1957, Bendix Corporation presented the Bendix Electrojector, one of the first electronically controlled manifold injection systems. Bosch built this system under licence, and marketed it from 1967 as the D-Jetronic. In 1973, Bosch introduced their first self-developed multi-point injection systems, the electronic L-Jetronic, and the mechanical, unpowered K-Jetronic. Their fully digital Motronic system was introduced in 1979. It found widespread use in German luxury saloons. At the same time, most American car manufacturers stuck to electronic single-point injection systems. In the mid-1980s, Bosch upgraded their non-Motronic multi-point injection systems with digital engine control units, creating the KE-Jetronic, and the LH-Jetronic. Volkswagen developed the digital "Digijet" injection system for their "Wasserboxer" water-cooled engines, which evolved into the Volkswagen Digifant system in 1985.
Cheap single-point injection systems that worked with either two-way or three-way catalyst converters, such as the Mono-Jetronic introduced in 1987, enabled car manufacturers to economically offer an alternative to carburettors even in their economy cars, which helped the extensive spread of manifold injection systems across all passenger car market segments during the 1990s. In 1995, Mitsubishi introduced the first petrol direct injection Otto engine for passenger cars, and the petrol direct injection has been replacing the manifold injection since, but not across all market segments; several newly produced passenger car engines still use multi-point injection.
References
Engine components
Fuel injection systems | Manifold injection | [
"Technology"
] | 3,525 | [
"Engine components",
"Engines"
] |
65,639,409 | https://en.wikipedia.org/wiki/Bendix%20Electrojector | The Bendix Electrojector is an electronically controlled manifold injection (EFI) system developed and made by Bendix Corporation. In 1957, American Motors (AMC) offered the Electrojector as an option in some of their cars; Chrysler followed in 1958. However, it proved to be an unreliable system that was soon replaced by conventional carburetors. The Electrojector patents were then sold to German car component supplier Bosch, who developed the Electrojector into a functioning system, the Bosch D-Jetronic, introduced in 1967.
Description
The Electrojector is an electronically controlled multi-point injection system that has an analogue engine control unit, the so-called "modulator" that uses the intake manifold vacuum and the engine speed for metering the right amount of fuel. The fuel is injected intermittently, and with a constant pressure of . The injectors are spring-loaded active injectors, actuated by a modulator-controlled electromagnet. Pulse-width modulation is used to change the amount of injected fuel: since the injection pressure is constant, the fuel amount can only be changed by increasing or decreasing the injection pulse duration. The modulator receives the injection pulse from an injection pulse generator that rotates in sync with the ignition distributor. The modulator converts the injection pulse into a correct injection signal for each fuel injector primarily by using the intake manifold and crankshaft speed sensor signals. It uses analogue transistor technology (i. e. no microprocessor) to do so. The system also supports setting the correct idle speed, mixture enrichment, and coolant temperature using additional resistors in the modulator.
History
The Electrojector was first offered by American Motors Corporation (AMC) in 1957. The Rambler Rebel was used to promote AMC's new engine. The Electrojector-injected engine was an option and rated at . It produced peak torque 500 rpm lower than the equivalent carburetor engine The cost of the EFI option was US$395 and it was available on 15 June 1957. According to AMC, the price would be significantly less than Chevrolet's mechanical fuel injection option. Initial problems with the Electrojector meant only pre-production cars had it installed so very few cars were sold and none were made available to the public. The EFI system in the Rambler worked well in warm weather, but was difficult to start in cooler temperatures.
Chrysler offered Electrojector on the 1958 Chrysler 300D, DeSoto Adventurer, Dodge D-500, and Plymouth Fury. The early electronic components were not reliable in an underhood environment and were not easily modified as engine control requirements advanced. Most of the 35 vehicles originally equipped with Electrojector were retrofitted with 4-barrel carburetors. The Electrojector patents were subsequently sold to Bosch.
Bosch developed their D-Jetronic (D for Druckfühlergesteuert, German for "pressure-sensor-controlled"), from the Electrojector, which was first used on the VW 1600TL/E in 1967. This was a speed/density system, using engine speed and intake manifold air density to calculate "air mass" flow rate and thus fuel requirements. This system was adopted by VW, Mercedes-Benz, Porsche, Citroën, Saab, and Volvo. Lucas licensed the system for production in Jaguar cars, initially in D-Jetronic form, before switching to L-Jetronic in 1978 on the XK6 engine.
References
Fuel injection systems
Embedded systems
Power control
Engine technology
Automotive technology tradenames
Bendix Corporation | Bendix Electrojector | [
"Physics",
"Technology",
"Engineering"
] | 735 | [
"Physical quantities",
"Computer engineering",
"Engines",
"Embedded systems",
"Computer systems",
"Engine technology",
"Power (physics)",
"Computer science",
"Power control"
] |
65,641,790 | https://en.wikipedia.org/wiki/MSU-DOE%20Plant%20Research%20Laboratory | The MSU-DOE Plant Research Laboratory (PRL), commonly referred to as Plant Research Lab,
is a research institute funded to a large extent by the U.S. Department of Energy Office of Science and located at Michigan State University (MSU)
in East Lansing, Michigan. The Plant Research Lab was founded in 1965, and it currently includes twelve laboratories that conduct collaborative basic research
into the biology of diverse photosynthetic organisms, including plants, bacteria, and algae, in addition to developing new technologies towards
addressing energy and food challenges.
History
1964-1978
The contract for the establishment of the MSU-DOE Plant Research Laboratory was signed on March 6, 1964, between the U.S. Atomic Energy Commission (AEC) and Michigan State University. The institute was initially funded by the AEC's Division of Biology and Medicine, which saw a need for improving the state of plant sciences in the United States. The Division aimed to create a new program at one or more universities where student interest in plant research could be fostered.
The contract signed between AEC and Michigan State University provided for a comprehensive research program in plant biology and related education and training at the graduate and postgraduate levels. The program was to draw strongly on related disciplines such as biochemistry, biophysics, genetics, microbiology, and others.
In 1966, personnel of the new program - called MSU-AEC Plant Research Laboratory at that time - moved into their new quarters in the Plant Biology Laboratories building at Michigan State University. The first research projects generally focused on problems specific to plants, such as cell growth and its regulation by plant hormones, cell wall structure and composition, and the physiology of flower formation; other research projects addressed general biological problems, such as the regulation of enzyme formation during development and cellular and genetic aspects of hormone action.
In the 1970s, federal funding of the Plant Research Lab changed hands a number of times. The AEC was abolished following the Energy Reorganization Act of 1974, and its functions were assigned to two new agencies. In 1975, the Plant Research Lab thus found itself supported by the newly formed Energy Research and Development Administration, which in turn, was consolidated into the U.S. Department of Energy (DOE) in 1978. The institute's name was modified in step with the changes at the federal level, finally settling on its current name, MSU-DOE Plant Research Laboratory.
1978-2006
The DOE broadened the laboratory's mandate to look at basic plant processes, especially regarding the growth of plants as a renewable resource, with the focus of research shifting to modern plant molecular biology. During that period, Plant Research Lab scientists were among the pioneers who introduced the use of the model plant, Arabidopsis thaliana, into plant biology.
Starting in the 1990s, the Plant Research Lab initiated a culture of group projects, which combined the talents of Plant Research Lab faculty members with scientists from other departments at Michigan State University, in order to tackle difficult and risky research projects. Projects included the biosynthesis of cell wall components, establishing a genetic system for the nitrogen-fixing actinomycete Frankia, studying the molecular basis of flower induction, studying membrane-tethered transcription factors, and others.
2006-present
In 2006, the Plant Research Lab's research mission was redirected to match the new priorities of the DOE's Office of Basic Energy Sciences (DOE-BES). The DOE program was undergoing reorganization, and the goals now focused on fundamental aspects of energy and carbon capture, conversion, and deposition in energy-rich molecules in both plants and microbes.
This change in research direction led to a reconfiguration of group research projects and to new faculty hires. In 2013, the group project model, first adopted in the 1990s, became the fundamental research model - "research teams addressing research themes" - for all DOE-BES funded research. Three primary research projects were initiated (go to section) to understand the basic science of photosynthetic organisms, including the exploration of photosynthetic processes across multiple scales of biological organization,
ranging from subcellular (e.g. photoactive compounds, enzymes, protein complexes and bacterial microcompartments, the thylakoid membrane), to the overall integration of photosynthesis in cells and organisms in their environments. Another aim is to understand photosynthesis in 'real life,' how it is regulated by changes in the natural environment and in response to environmental challenges. The long-term goal uniting these research areas is to improve photosynthetic efficiency and to develop new industrial technological applications.
As of 2020, the Plant Research Lab had over 900 alumni worldwide, many of whom have assumed important academic, industrial, and governmental positions. Since its inception, 18 Plant Research Lab scientists have been elected members of the U.S. National Academy of Sciences, a prestigious honor for scientists in the United States; 21 have been elected American Association for the Advancement of Science Fellows; and 23 have been elected American Society of Plant Biologists Fellows.
Research
Department of Energy Grant
DOE-funded collaborative projects drive the research conducted at the MSU-DOE Plant Research Laboratory. The projects involve all twelve labs at the Plant Research Lab and rely on their diverse areas of expertise to tackle key problems too large to study in individual labs. The research addresses some of today's most challenging scientific questions, with implications for renewables, food sustainability, and medical and industrial technologies.
One research area examines how photosynthesis adapts to changing environmental conditions, focusing on the functions of genes and pathways involved in enhancing photosynthetic robustness in dynamic environments. The research tackles this problem by developing new scientific instruments that test plants and photosynthetic bacteria under a wide range of realistic conditions and identify undiscovered processes that tune photosynthetic activity rates; and by creating automated big data processing streams and bioinformatic pipelines.
A second research area addresses how photosynthetic organisms sense and regulate the proportioning of energy and carbon between growth and other metabolic processes, such as protection against abiotic and biotic stresses, for example. The vision for this project is to holistically understand these photosynthetic and metabolic processes over a wide range of spatial and temporal scales and to develop models that describe how these processes interact.
A third research area encompasses structural and functional studies of proteins that are used to construct subcellular microcompartments in cyanobacteria, with the long-term goal of repurposing these natural compartments to engineer improvements in photosynthesis, new renewable energy sources, and new compounds and molecular structures for medical or industrial uses.
Other Research and Developed Technologies
In addition to the collaborative projects funded by the DOE, individual laboratories conduct molecular research in diverse areas, including algal biofuels, plant resistance to biotic and abiotic threats, secretory membrane dynamics, dynamics of energy organelles (ie, mitochondria, peroxisomes, and chloroplasts), and molecular genetic and biochemical analyses of photomorphogenesis.
The Plant Research Lab has also developed innovative technologies and methods to help address new research questions. Current examples include:
Synthetic biology toolboxes to study and modify bacterial microcompartments or to develop synthetic microbial consortia or to engineer bacteria, algae, and plants as production systems for biofuels and other valuable medical or industrial compounds.
Dynamic Environmental Photosynthetic Imaging growth chambers which capture a variety of environmental conditions seen in the field, such as light intensities or weather patterns, and replay them in a laboratory setting. The chambers are equipped with cameras that produce real-time heat maps of photosynthetic activity, down to the level of individual leaves.
PhotosynQ, a platform that combines a hand-held device with cloud-based storage and analytical capabilities that allow users to measure plant health at a fundamental level in the field and to collect data anywhere in the world.
Environmental Photobioreactors which enable scientists to study algae under the same conditions found in outdoor ponds, but in the much more controlled setting of the laboratory.
Operations and governance
Michigan State University operates the MSU-DOE Plant Research Laboratory under a contract with the Department of Energy. The institute director reports to both to Michigan State University's College of Natural Sciences and the U.S. Department of Energy, Office of Science, Basic Energy Sciences program.
The Plant Research Lab is located on Michigan State University's East Lansing campus and has groups in both the Plant Biology Laboratory and Molecular Plant Sciences buildings. The institute consists of twelve research laboratories, each headed by a tenure-track faculty member, and has around 150 employees. Its twelve tenure-track faculty also hold appointments in academic departments and programs at Michigan State University.
The Plant Research Lab is solely a research institute and does not grant academic degrees to its students. Consequently, graduate students at the Plant Research Lab are appointed to both the institute and at least one of the affiliated academic departments or programs, the latter of which grant Ph.D. degrees. Postdoctoral associates are appointed to the Plant Research Lab with Michigan State University privileges, such as healthcare and funding.
Laboratory directors
Anton Lang (1965-1978)
Hans Kende (1978-1980)
Charles Arntzen (1980-1984)
Hans Kende (1984-1988)
Peter Wolk (1988-1992)
Kenneth Keegstra (1993-2006)
Michael Thomashow (2006-2015)
Christoph Benning (2015–present)
References
External links
Official Website
Biological research institutes in the United States
Botany
Michigan State University
East Lansing, Michigan
University and college laboratories in the United States
United States Department of Energy
United States Atomic Energy Commission
1965 establishments in Michigan | MSU-DOE Plant Research Laboratory | [
"Biology"
] | 1,967 | [
"Plants",
"Botany"
] |
65,642,306 | https://en.wikipedia.org/wiki/11-Ketoandrosterone | 11-Ketoandrosterone is an endogenous steroid.
Function
11-Ketoandrosterone is an androgen. Androgens are sex hormones that stimulate or control the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. However, the potency of 11-ketoandrosterone as an agonist of androgen receptors was not known .
Structure
11-Ketoandrosterone is a 11-keto form and a metabolite of androsterone.
11-Ketoandrosterone belongs to a group of 11-oxyandrogens, i.e. 11-oxygenated (oxygen atom on C11 position forms a ketone group) 19-carbon steroids. 11-oxyandrogens are potent and clinically relevant agonists of the androgen receptors. Potency of 11-ketotestosterone, an 11-oxyandrogen, is similar to that of testosterone. 11-ketotestosterone, derived from 11β-hydroxyandrostenedione, may serve as the main androgen for healthy women.
Clinical relevance
11-Ketoandrosterone is a metabolite that may be biosynthesized within the androgen backdoor pathway, a metabolic pathway for androgen synthesis that bypasses testosterone as an intermediate product.
SRD5A2 catalyzes the 5α-reduction of 11-ketotestosterone that terminates at 11-ketoandrosterone, but only causes a small amount of 11-ketotestosterone inactivation. However, since the metabolism of the glucocorticoid cortisol also produces 11-ketocholosterone, 11-ketoandrosterone may be considered as a more specific urinary marker for the production of 11-ketotestosterone.
See also
Androgen backdoor pathway
Androsterone
References
Human metabolites
Secondary alcohols
Anabolic–androgenic steroids
Androstanes
Hormones of the suprarenal cortex
Ketones | 11-Ketoandrosterone | [
"Chemistry"
] | 442 | [
"Ketones",
"Functional groups"
] |
65,642,628 | https://en.wikipedia.org/wiki/Tst26 | The Tst26 toxin is a voltage-gated potassium channel blocker present in the venom of Tityus stigmurus, a species of Brazilian scorpion. Tst26 selectively blocks Kv1.2 and Kv1.3 channels.
Etymology
Tst26 is named after the species it was discovered from and a characteristic of the process in which it was obtained. Venom from Tityus stigmurus was analysed using high-performance liquid chromatography (HPLC). Peptides were separated based on the elution time from HPLC, and when the sample which elutes at 26 minutes was sequenced a distinct amino acid sequence was discovered. When this sequence was further characterized, it was revealed to be a unique potassium blocker and was named Tst26. Tst was derived from the abbreviation of the species of scorpion it was discovered from, Tityus stigmurus, and 26 was derived from the elution time of the sample it was obtained from. Tst26 has high sequence similarity with other peptides from the α-KTx 4 family and therefore this toxin has the systematic name α-KTx 4.6.
Sources
This toxin was discovered in the venom of the Tityus stigmurus. Tityus stigmurus is a species of Brazilian scorpion found predominantly in the northeastern regions of Brazil.
Chemistry
The chemical structure of Tst26 is similar to the structure of other potassium blocking peptides from scorpion venom. Tst26 comprises 37 amino acids that are tightly connected through three disulfide bridges. The peptide's experimental molecular mass of 3941.0 Da corresponds very well with its theoretical molecular mass of 3940.8 Da. The presence of lysine and tyrosine at position 27 and 36 respectively allows for potassium channel recognition.
Target
Tst26 selectively blocks Kv1.2 and Kv1.3 voltage gated potassium channels and has high affinity to both channels. It has an affinity (Kd) of 1.9 nM for Kv1.2 and of 10.7 nM for Kv1.3. Tst26 did not affect any of the other tested channels Kv1.1, Kv1.4, Kv1.5, hERG, IKCa1, BKCa and Nav1.5.
Mode of action
Tst26 selectively blocks Kv1.2 and Kv1.3 receptors, and it is assumed that Tst26 blocker works as a pore blocker owing to its similarity with other blockers in its family. This toxin does not affect the voltage-dependence of (steady state) activation or inactivation of the potassium channels but did slow down the inactivation of Kv1.3 channels.
References
Ion channel toxins
Neurotoxins
Scorpion toxins
Potassium channel blockers | Tst26 | [
"Chemistry"
] | 581 | [
"Neurochemistry",
"Neurotoxins"
] |
65,642,922 | https://en.wikipedia.org/wiki/Estofado | Estofado () is an artistic technique that imitates the appearance of gold brocade. The term comes from the Italian "stoffa" (fabric) in reference to the fine textiles it seeks to reproduce. Its origin is found in the Gothic period, its use became more popular during the renaissance and baroque periods, particularly in Spain and its cultural sphere of influence, where it became prevalent. While estofado is mostly used for wooden sculpture, either statuary in the round or reliefs, it is can also be used on other mediums, such as stone sculptures or panel paintings.
In 1777 the "Real Academia de Bellas Artes de San Fernando" assumes the authority to approve all designs for new altarpieces, and according to the new Neoclassical tastes, required that polychrome woulld should be replaced with "marble or other suitable stones". This shift in style caused the technique to be relegated to a secondary level, and was seen as common or popular by the cultured society.
Gallery
References
Roman, Rolf, Baroque: Architecture, Sculpture, Painting, 2007
Explanation of the "Estofado" technique on the Getty Museum website
Definition from glosarioarquitectonico.com
Definition of Estofado by Merriam-Webster
Artistic techniques
Gold
Metal plating | Estofado | [
"Chemistry"
] | 263 | [
"Metallurgical processes",
"Coatings",
"Metal plating"
] |
65,644,428 | https://en.wikipedia.org/wiki/Simons%27%20formula | In the mathematical field of differential geometry, the Simons formula (also known as the Simons identity, and in some variants as the Simons inequality) is a fundamental equation in the study of minimal submanifolds. It was discovered by James Simons in 1968. It can be viewed as a formula for the Laplacian of the second fundamental form of a Riemannian submanifold. It is often quoted and used in the less precise form of a formula or inequality for the Laplacian of the length of the second fundamental form.
In the case of a hypersurface of Euclidean space, the formula asserts that
where, relative to a local choice of unit normal vector field, is the second fundamental form, is the mean curvature, and is the symmetric 2-tensor on given by .
This has the consequence that
where is the shape operator. In this setting, the derivation is particularly simple:
the only tools involved are the Codazzi equation (equalities #2 and 4), the Gauss equation (equality #4), and the commutation identity for covariant differentiation (equality #3). The more general case of a hypersurface in a Riemannian manifold requires additional terms to do with the Riemann curvature tensor. In the even more general setting of arbitrary codimension, the formula involves a complicated polynomial in the second fundamental form.
References
Footnotes
Books
Articles
Differential geometry of surfaces
Riemannian manifolds | Simons' formula | [
"Mathematics"
] | 298 | [
"Riemannian manifolds",
"Space (mathematics)",
"Metric spaces"
] |
65,644,883 | https://en.wikipedia.org/wiki/Maria%20Uriarte | María Uriarte is an ecologist who specializes in the processes that drive tropical forest dynamics, especially after extreme weather events. She is currently a professor in the Department of Ecology, Evolution, and Environmental Science at Columbia University and serves as adjunct faculty in the Department of Ecology at the University of São Paulo, Brazil. She conducts research primarily in Puerto Rico and Brazil and is associated with the Next Generation Ecosystem Experiments (NGEE) tropics and ForestGeo research groups.
Education and career
Uriarte joined the Peace Corps in The Gambia, West Africa in 1989, where she worked with women's agricultural cooperatives in vegetation production improvement. She earned her M.S. in Environmental Studies from Yale School of Forestry and her Ph.D. in Ecology from Cornell University. She did her postdoctoral work at the Cary Institute of Ecosystem Studies, where she studied how forest recover from hurricane disturbances by developing different statistical tools.
Research
Several of Uriarte's projects have been featured in population media outlets, such as The New York Times, PBS and CNN. Much of the covered work on these and other media outlets surrounds the effects of Hurricane Maria on Puerto Rican forest dynamics, and highlights the potential for stronger hurricanes to have adverse effects on forests and accelerate climate change. Other highlighted work included projects that use Artificial Intelligence to identify tropical tree species using aerial photos collected by NASA in El Yunque National Forest, Puerto Rico.
Honors and awards
María Uriarte received the Leopold Leadership Fellowship from the Woods Institute for the Environment, Stanford University and a Science without Borders Fellowship from the Brazilian government.
References
External links
Faculty page
Uriarte lab website
Year of birth missing (living people)
Living people
Ecologists
Women ecologists
Peace Corps people
Yale School of Forestry & Environmental Studies alumni
Cornell University alumni
Academic staff of the University of São Paulo
Columbia University faculty | Maria Uriarte | [
"Environmental_science"
] | 368 | [
"Ecologists",
"Environmental scientists"
] |
65,644,929 | https://en.wikipedia.org/wiki/K2-315b | K2-315b is an exoplanet located 185.3 light years away from Earth in the southern zodiac constellation Libra. It orbits the red dwarf K2-315.
Discovery
K2-315b was discovered in 2020 by astronomers in an observatory using the Kepler space telescope. It is also nicknamed the "Pi Earth" because it takes approximately 3.14 days to orbit the host star.
Physical properties
The planet is thought to be a small rocky planet, even though composition is unknown. Since it orbits very close to its star, it is too hot to host life, due to it having a scorching temperature of 450 K. Not much is known about it because it was just discovered, but it is similar to Earth, having a radius 95% that of Earth, very similar to Venus, but has 81% Earth's mass.
Host star
K2-315 is a star in the southern zodiac constellation Libra. It has an apparent magnitude of 17.67, requiring a powerful telescope to be seen. The star is relatively close at a distance of 185 light years but is receding with a radial velocity of .
K2-315 has a stellar classification of M3.5 V, indicating that it is a M-type main-sequence star (with 14% uncertainty). It has 17.4% the mass of the Sun and 20% its radius. Typical for red dwarves, it has a luminosity less than 1% of the Sun, which yields an effective temperature of 3,300 K. Unlike most planetary hosts, K2-315 is metal-deficient, with an iron abundance only 57% that of the Sun. It is estimated to be over a billion years old, and has a projected rotational velocity less than .
References
Libra (constellation)
Exoplanets discovered in 2020
Exoplanets discovered by K2 | K2-315b | [
"Astronomy"
] | 380 | [
"Libra (constellation)",
"Constellations"
] |
49,054,091 | https://en.wikipedia.org/wiki/Westerly%20wind%20burst | A westerly wind burst (WWB) or westerly wind event (WWE)https://glossary.ametsoc.org/wiki/Westerly_wind_burst is a phenomenon commonly associated with El Niño events, whereby the typical east-to-west trade winds across the equatorial Pacific shift to west-to-east.
Definition
A westerly wind burst is defined by Harrison and Vecchi (1997) as sustained winds of over a period of 5–20 days. However, no concrete definition has been determined, with Tziperman and Yu (2007) defining them as having winds of and lasting "at least a few days".
On average, three of these events take place each year, but are significantly more common during El Niño years. They have been linked to various mesoscale phenomena, including tropical cyclones, mid-latitude cold surges, and the Madden–Julian oscillation. Their connection with Kelvin waves also indicate a connection with the onset of El Niño events, with every major occurrence since the 1950s featuring a westerly wind burst upon their onset.
Studies
Recent studies, including Yu et al. (2003), have indicated some correlation between westerly wind bursts and the El Niño–Southern Oscillation (ENSO). These events occur more frequently when the equatorial Pacific warm pool is extended by ENSO events. A significant relationship exists between the frequency of westerly wind bursts and the central equatorial Pacific sea surface temperatures, with events commonly taking place when temperatures were present. The wind bursts also traveled along with the warm pool, propagating west to east.
Cyclones
A westerly wind burst event can often result in the formation of twin tropical cyclones in the Pacific, with events occurring annually on average. These events spur counter-clockwise rotation in the Northern Hemisphere and clockwise rotation in the Southern Hemisphere—a key component of low pressure systems. For example, during July 2015 Typhoon Chan-hom and Cyclone Raquel developed simultaneously over the Northwestern and Southwestern Pacific, respectively, in conjunction with a westerly wind burst. This was also the only known instance of twin cyclones during July and attributed to the record strength of the 2014–16 El Niño event. Another unusually strong wind burst led to the atypical formations of Tropical Depression Nine-C and Hurricane Pali in late December 2015 and early January 2016, respectively along with the formation of Cyclone Ula in the Central and Southwestern Pacific.
Similarly, the formation of twin cyclones along the equatorial Pacific can spur the formation of a westerly wind burst and enhance El Niño events. In May 2002, a strong westerly wind burst moved from west to east across the Indian Ocean, producing two separate sets of twin cyclones. It first led to the development of Cyclone Kesiny in the south-west Indian Ocean and a storm that struck Oman, and later spawned a deep depression that struck Myanmar and Tropical Storm Errol to the southwest of Indonesia.
See also
Trade winds
References
Tropical meteorology
Tropical cyclone meteorology
Weather hazards | Westerly wind burst | [
"Physics"
] | 606 | [
"Weather",
"Physical phenomena",
"Weather hazards"
] |
49,055,689 | https://en.wikipedia.org/wiki/IEEE%20802.11ay | IEEE 802.11ay, Enhanced Throughput for Operation in License-exempt Bands above 45 GHz, is a follow-up to IEEE 802.11ad WiGig standard which quadruples the bandwidth and adds MIMO up to 8 streams. Development started in 2015 and the final standard IEEE 802.11ay-2021 was approved in March 2021.
Technical details
802.11ay is a type of WLAN in the IEEE 802.11 family of Wi-Fi WLANs. It is an improvement on IEEE 802.11ad rather than a new standard. It uses the 60 GHz band and has a transmission rate of 20–40 Gbit/s and an extended transmission distance of 300–500 meters. It includes mechanisms for channel bonding and MU-MIMO technologies. It was originally expected to be released in 2017, but was delayed until 2021.
Where 802.11ad uses a maximum of 2.16 GHz bandwidth, 802.11ay bonds four of those channels together for a maximum bandwidth of 8.64 GHz. MIMO is also added with a maximum of four streams. The link-rate per stream is 44 Gbit/s, with four streams this goes up to 176 Gbit/s. Higher order modulation is also added, probably up to 256-QAM.
Applications could include replacement for Ethernet and other cables within offices or homes, and provide backhaul connectivity outside for service providers.
802.11ay should not be confused with the similarly named 802.11ax that was officially approved in 2021. The 802.11ay standard is designed to run at much higher frequencies. The lower frequency of 802.11ax enables it to penetrate walls somewhat, while 802.11ay is generally blocked by walls.
Draft versions
Draft version 0.1 of 802.11ay was released in January 2017, followed by draft version 0.2 in March 2017. Draft version 1.0 was made available in November 2017, and draft 1.2 was available as of April 2018.
Draft version 7.0 was released in December 2020 and the Final 802 Working Group Approval was received in February 2021.
See also
List of WLAN channels
IEEE
References
External links
IEEE 802.11ay-2021 — IEEE Standard for Information Technology — Telecommunications and Information Exchange between Systems Local and Metropolitan Area Networks — Specific Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 2: Enhanced Throughput for Operation in License-exempt Bands above 45 GHz.
FAQ: What is 802.11ay wireless technology?
Status of IEEE 802.11 Next Generation 60 GHz (NG60) Study Group" at IEEE802
Wireless networking | IEEE 802.11ay | [
"Technology",
"Engineering"
] | 537 | [
"Wireless networking",
"Computer networks engineering"
] |
49,057,371 | https://en.wikipedia.org/wiki/Oxalotrophic | Oxalotrophic bacteria are bacteria capable of using oxalate as their sole source of carbon and energy. Oxalate is the anion of a salt of oxalic acid; oxalotrophs often consume calcium oxalate. Oxalotrophic bacteria are often facultative methylotrophs.
References
Bacteria
Bacteriology | Oxalotrophic | [
"Biology"
] | 71 | [
"Bacteria stubs",
"Prokaryotes",
"Microorganisms",
"Bacteria"
] |
49,057,618 | https://en.wikipedia.org/wiki/C21H22N2O3 | {{DISPLAYTITLE:C21H22N2O3}}
The molecular formula C21H22N2O3 (molar mass: 350.41 g/mol, exact mass: 350.1630 u) may refer to:
NNC-711
Perakine
Vomilenine
Molecular formulas | C21H22N2O3 | [
"Physics",
"Chemistry"
] | 68 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
49,058,288 | https://en.wikipedia.org/wiki/WPGMA | WPGMA (Weighted Pair Group Method with Arithmetic Mean) is a simple agglomerative (bottom-up) hierarchical clustering method, generally attributed to Sokal and Michener.
The WPGMA method is similar to its unweighted variant, the UPGMA method.
Algorithm
The WPGMA algorithm constructs a rooted tree (dendrogram) that reflects the structure present in a pairwise distance matrix (or a similarity matrix). At each step, the nearest two clusters, say and , are combined into a higher-level cluster . Then, its distance to another cluster is simply the arithmetic mean of the average distances between members of and and and :
The WPGMA algorithm produces rooted dendrograms and requires a constant-rate assumption: it produces an ultrametric tree in which the distances from the root to every branch tip are equal. This ultrametricity assumption is called the molecular clock when the tips involve DNA, RNA and protein data.
Working example
This working example is based on a JC69 genetic distance matrix computed from the 5S ribosomal RNA sequence alignment of five bacteria: Bacillus subtilis (), Bacillus stearothermophilus (), Lactobacillus viridescens (), Acholeplasma modicum (), and Micrococcus luteus ().
First step
First clustering
Let us assume that we have five elements and the following matrix of pairwise distances between them :
In this example, is the smallest value of , so we join elements and .
First branch length estimation
Let denote the node to which and are now connected. Setting ensures that elements and are equidistant from . This corresponds to the expectation of the ultrametricity hypothesis.
The branches joining and to then have lengths (see the final dendrogram)
First distance matrix update
We then proceed to update the initial distance matrix into a new distance matrix (see below), reduced in size by one row and one column because of the clustering of with .
Bold values in correspond to the new distances, calculated by averaging distances between each element of the first cluster and each of the remaining elements:
Italicized values in are not affected by the matrix update as they correspond to distances between elements not involved in the first cluster.
Second step
Second clustering
We now reiterate the three previous steps, starting from the new distance matrix :
Here, is the smallest value of , so we join cluster and element .
Second branch length estimation
Let denote the node to which and are now connected. Because of the ultrametricity constraint, the branches joining or to , and to are equal and have the following length:
We deduce the missing branch length:
(see the final dendrogram)
Second distance matrix update
We then proceed to update the matrix into a new distance matrix (see below), reduced in size by one row and one column because of the clustering of with :
Of note, this average calculation of the new distance does not account for the larger size of the cluster (two elements) with respect to (one element). Similarly:
The averaging procedure therefore gives differential weight to the initial distances of matrix . This is the reason why the method is weighted, not with respect to the mathematical procedure but with respect to the initial distances.
Third step
Third clustering
We again reiterate the three previous steps, starting from the updated distance matrix .
Here, is the smallest value of , so we join elements and .
Third branch length estimation
Let denote the node to which and are now connected.
The branches joining and to then have lengths (see the final dendrogram)
Third distance matrix update
There is a single entry to update:
Final step
The final matrix is:
So we join clusters and .
Let denote the (root) node to which and are now connected.
The branches joining and to then have lengths:
We deduce the two remaining branch lengths:
The WPGMA dendrogram
The dendrogram is now complete. It is ultrametric because all tips ( to ) are equidistant from :
The dendrogram is therefore rooted by , its deepest node.
Comparison with other linkages
Alternative linkage schemes include single linkage clustering, complete linkage clustering, and UPGMA average linkage clustering. Implementing a different linkage is simply a matter of using a different formula to calculate inter-cluster distances during the distance matrix update steps of the above algorithm. Complete linkage clustering avoids a drawback of the alternative single linkage clustering method - the so-called chaining phenomenon, where clusters formed via single linkage clustering may be forced together due to single elements being close to each other, even though many of the elements in each cluster may be very distant to each other. Complete linkage tends to find compact clusters of approximately equal diameters.
See also
Neighbor-joining
Molecular clock
Cluster analysis
Single-linkage clustering
Complete-linkage clustering
Hierarchical clustering
References
Bioinformatics algorithms
Computational phylogenetics
Cluster analysis algorithms | WPGMA | [
"Biology"
] | 1,025 | [
"Genetics techniques",
"Computational phylogenetics",
"Bioinformatics algorithms",
"Bioinformatics",
"Phylogenetics"
] |
49,058,608 | https://en.wikipedia.org/wiki/Prostanoic%20acid | Prostanoic acid (7-[(1S,2S)-2-octylcyclopentyl]heptanoic acid) is a saturated fatty acid which contains a cyclopentane ring. Its derivatives are prostaglandins - physiologically active lipid substances. Prostanoic acid is not found in nature, but it can be synthesized in vitro.
Synthesis
For the first time the synthesis of prostanoic acid from 1-formylcyclopentene was considered in detail in the scientific literature in 1975 by a group of French pharmacists. One year later, a group of Japanese scientists, who worked in the central research laboratory of the "Sankyo Co., Ltd." company (Shinagawa, Tokyo), published another method for obtaining prostanoic acid from 2-[4-hydroxy-5-(methoxymethyl)cyclopent-2-en-1-yl] acetic acid. In 1986, a group of Japanese scientists from Kyushu University in Fukuoka proposed their own scheme for obtaining prostanoic acid from limonene.
See also
Prostaglandin
Saturated fat
Fatty acid
Fatty acid synthesis
List of saturated fatty acids
List of unsaturated fatty acids
References
Fatty acids
Lipids
Prostaglandins | Prostanoic acid | [
"Chemistry"
] | 271 | [
"Biomolecules by chemical classification",
"Organic compounds",
"Organic compound stubs",
"Lipids",
"Organic chemistry stubs"
] |
49,059,554 | https://en.wikipedia.org/wiki/Clay%20chemistry | Clay chemistry is an applied subdiscipline of chemistry which studies the chemical structures, properties and reactions of or involving clays and clay minerals. It is a multidisciplinary field, involving concepts and knowledge from inorganic and structural chemistry, physical chemistry, materials chemistry, analytical chemistry, organic chemistry, mineralogy, geology and others.
The study of the chemistry (and physics) of clays and clay minerals is of great academic and industrial relevance as they are among the most widely used industrial minerals, being employed as raw materials (ceramics, pottery, etc.), adsorbents, catalysts, additives, mineral charges, medicines, building materials and others.
The unique properties of clay minerals including: nanometric scale layered construction, presence of fixed and interchangeable charges, possibility of adsorbing and hosting (intercalating) molecules, ability of forming stable colloidal dispersions, possibility of tailored surface and interlayer chemical modification and others, make the study of clay chemistry a very important and extremely varied field of research.
Many distinct fields and knowledge areas are impacted by the physico-chemical behavior of clay minerals, from environmental sciences to chemical process engineering, from pottery to nuclear waste management.
Their cation exchange capacity (CEC) is of great importance in the balance of the most common cations in soil (Na+, K+, NH4+, Ca2+, Mg2+) and pH control, with direct impact on the soil fertility. It also plays an important role in the fate of most Ca2+ arriving from land (river water) into the seas.
The ability to change and control the CEC of clay minerals offers a valuable tool in the development of selective adsorbents with applications as varied as chemical sensors or pollution cleaning substances for contaminated water, for example.
The understanding of the reactions of clay minerals with water (intercalation, adsorption, colloidal dispersion, etc.) are indispensable for the ceramic industry (plasticity and flow control of ceramic raw mixtures, for example). Those interactions also influence a great number of mechanical properties of soils, being carefully studied by building and construction engineering specialists.
The interactions of clay minerals with organic substances in the soil also plays a vital role in the fixation of nutrients and fertility, as well as in the fixation or leaching of pesticides and other contaminants. Some clay minerals (kaolinite) are used as carrier material for fungicides and insecticides.
The weathering of many rock types produce clay minerals as one of its last products. The understanding of these geochemical processes is also important for the understanding of geological evolution of landscapes and macroscopic properties of rocks and sediments. Presence of clay minerals in Mars, detected by the Mars Reconnaissance Orbiter in 2009 was another strong evidence of the existence of water on the planet in previous geological eras.
The possibility to disperse nanometric scaled clay mineral particles into a matrix of polymer, with the formation of an inorganic-organic nanocomposite has prompted a large resurgence in the study of these minerals from the late 1990s.
In addition, study of clay chemistry is also of great relevance to the chemical industry, as many clay minerals are used as catalysts, catalyst precursors or catalyst substrates in a number of chemical processes, like automotive catalysts and oil cracking catalysts.
See also
References
Pottery
Bricks
Clay
Chemistry
Geochemistry
Soil-based building materials | Clay chemistry | [
"Chemistry"
] | 702 | [
"nan"
] |
49,060,043 | https://en.wikipedia.org/wiki/Zimmermann%20reagent | The Zimmermann reagent is used as a simple spot-test used in chromatography to presumptively identify alkaloids, especially benzodiazepines, as well as other compounds. It is therefore used in drugs testing.
It is a two-component reagent, with the first component composed of 1,3-dinitrobenzene (1% w/v) in methanol and the second component composed of 15% potassium hydroxide in water.
One drop of each component is added to the sample being tested and the resulting colour change is observed to give an indication of the identity of the compound.
The reagent works by forming a reddish-purple Meisenheimer complex at C3 for diazepines with a carbonyl at C2 and an alkyl group at N1. Without these groups it is not possible to form the methylene compound which reacts with dinitrobenzene but triazolo compounds may react.
It is named for the American biochemist Robert Zimmermann (b.1937).
See also
Drug checking
Dille–Koppanyi reagent
Folin's reagent
Liebermann reagent
Mandelin reagent
Marquis reagent
Mecke reagent
Simon's reagent
Zwikker reagent
Froehde reagent
References
External links
Testing Steroids
Chemical tests
Analytical reagents
Drug testing reagents | Zimmermann reagent | [
"Chemistry"
] | 298 | [
"Drug testing reagents",
"Analytical reagents",
"Chemical tests"
] |
49,060,071 | https://en.wikipedia.org/wiki/Fove | FOVE is the first virtual reality headset to utilize built-in eye tracking technology. It was created by a Tokyo-based startup founded by Yuka Kojima (CEO) and Lochlainn Wilson (CTO). Announced in 2014, FOVE's technology uses infrared sensors within the headset to accurately track the user's pupils and eye movements with low latency, allowing the user to target and interact with objects by making eye contact with them.
Kickstarter Campaign for FOVE began in May, 2015, with an initial funding goal of $250,000. The goal was reached in less than 4 days. Backers who contributed $349+ were originally promised to receive a FOVE HMD in May, 2016. FOVE's Kickstarter campaign ultimately raised a total of $480,650.
Features
Eye tracking with an accuracy of 1/20 of a degree
Foveated rendering – The user's gaze is tracked and calculated so the graphical resources are allocated to where he or she is looking. The different areas of VR world sharpens and blurs depending on where the eyes are focusing.
Move the head naturally – With eye tracking, users can avoid unnecessary head movements and minimize simulator sickness.
Aim with the eyes – The user can target and interact with objects by glancing at them. They can use their gaze to aim weapon crosshairs in compatible FPS games, or create contextual menus for a gaze-based interface.
Make eye contact – The user can easily make eye contact with virtual characters in-game, which could potentially be used to communicate emotions. Characters' behaviors and reactions could change when they are watched.
Hardware
FOVE will utilize SteamVR's Lighthouse technology for positional tracking.
Developer
FOVE SDK - integrates content from Unity, Unreal Engine and Cryengine. Developers can port existing VR content into FOVE or create new content.
API for Foveated rendering.
History
September 9, 2014 - FOVE was revealed at Tech Crunch Disrupt SF 2014.
May 19, 2015 - Kickstarter Campaign began.
May 23, 2015 - Kickstarter Goal of $250,000 was reached
June 25, 2015 - FOVE announced that it received an undisclosed amount of funding from Samsung Ventures, the venture capital arm of the Korean conglomerate.
June 25, 2015 - FOVE announced that it will use SteamVR's Lighthouse for positional tracking.
March 23, 2016 - FOVE closed an $11 million Series A funding round, but delayed shipment to Fall 2016 because of difficulty sourcing components.
References
Head-mounted displays | Fove | [
"Biology"
] | 525 | [
"Medical technology companies",
"Life sciences industry"
] |
49,060,551 | https://en.wikipedia.org/wiki/Pholiota%20adiposa | Pholiota adiposa is a slimy, scaly, yellow-brown mushroom. It is edible, and found in North America, Europe, and Asia. It grows parasitically or saprotrophically, most often on beech species, fruiting in bunches between August and November. Several compounds produced by this mushroom, for example methyl gallate, are of interest for their medicinal properties.
Taxonomy
It was originally described by German naturalist August Batsch in 1786 as a species of Agaricus. Paul Kummer transferred it to the genus Pholiota in 1871.
Description
P. adiposa produces a mushroom. The cap is a yellow to brown ochre with dark, concentrically arranged scales, producing a brown spore print. The name adiposa comes from the slimy, oily appearance of the cap. The fungus is fasciculate, meaning it grows in bunches. Gills are crowded and yellow to brown colored. The stipe is cylindrical, broadening slightly at the base. It is typically 5-20 x .8-2.5 cm, has scales, and is sometimes curved. All tissues of this fungus have clamp connections. It is edible, and regularly consumed in many parts of Asia[7],[8].
Spores are ovoid to ellipsoid, smooth, brown colored, and around 7.5-9.5 x 5-6.3 μm in size. These spores are carried on cylindrical or clavate basidia with 4 sterigmata, however occasionally only 2-3 are present. P. adiposa has Chrysocystidia (25-56 x 7.5-11 μm) and Cheilocystidia (20-50 x 5-17 μm). Cheilocystidia of P. adiposa can be fusiform, cylindrical, clavate, lageniform, or obovoid.
P. adiposa and two closely related species, P. aurivella and P. limonella, are sometimes referred to as the P. adiposa complex. These species are morphologically very similar, however identifications can be made based on spore size or substrate the fungus is growing on.
Habitat and Ecology
P. adiposa has been documented in North America, Europe, and Asia. It can grow parasitically on live stems of trees, or as a saprotroph on dead wood. Substrates can be various beech species, poplar, and willow trees. Fruitification occurs between August and November, most commonly between September and October. P. adiposa grows above ground, as opposed to fungi which prefer buried wood. It can grow in temperature ranges between 10-30°C, with an optimal temperature of 25°C. Mycelial growth is severely suppressed below 5°C or above 35°C. In growth media. P. adiposa can grow in a pH of 5-9, growing the best at a pH of 6.
Bioactive Compounds
P. adiposa produces many bioactive compounds that are of interest for potential medicinal properties. These include methyl gallate, Angiotensin 1-converting Enzyme (ACE) inhibitory peptide, and various polysaccharides with antitumor and antioxidant properties. The purported health benefits of this fungus has generated interest in improving the yields of commercially cultivated P. adiposa.
Methyl Gallate
P. adiposa is the first fungus from which methyl gallate has been extracted. Methyl gallate has been studied for its antioxidant and related HIV-1 treatment properties. Antioxidants isolated from natural sources are desired due to their generally low cytotoxicity. Methyl Gallate was shown to preferentially scavenge superoxide (O2-) ions, which have been hypothesized to be involved in HIV-LTR activation.
Polysaccharides
Various polysaccharides isolated from P. adiposa have been shown to have anti tumor effects in mice. One dubbed SPAP2-1 interfered with the cell cycle and induced apoptosis in HeLa cells. Another called PAP-1a was combined with gold nanoparticles, increasing the macrophage count in mice. Other polysaccharides have been isolated which exhibit antioxidant effects. An overview of the literature on P. adiposa polysaccharides has suggested their antitumor abilities are closely tied to their antioxidant abilities.
See also
List of Pholiota species
References
External links
Strophariaceae
Fungi of Europe
Fungi described in 1786
Taxa named by August Batsch
Fungus species | Pholiota adiposa | [
"Biology"
] | 960 | [
"Fungi",
"Fungus species"
] |
49,062,556 | https://en.wikipedia.org/wiki/Kepler-419c | Kepler-419c (also known by its Kepler Object of Interest designation KOI-1474.02) is a super-Jupiter exoplanet orbiting within the habitable zone of the star Kepler-419, the outermost of two such planets discovered by NASA's Kepler spacecraft. It is located about 3,400 light-years (1040 parsecs )from Earth in the constellation Cygnus. The exoplanet was found by using the transit timing variation method, in which the variations of transit data from an exoplanet are studied to reveal a more distant companion.
Physical characteristics
Mass, radius and temperature
Kepler-419c is a super-Jupiter, an exoplanet that has a radius and mass greater than that of the planet Jupiter. It has a temperature of , somewhat cooler than the equilibrium temperature of the Earth. It has a mass of 7.2 , and a likely radius of around 1.13 , based on its high mass.
Host star
The planet orbits an (F-type) star named Kepler-419. The star has a mass of 1.39 and a radius of 1.75 . It has a surface temperature of 6430 K and is 2.8 billion years old. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 12. It is too dim to be seen with the naked eye.
Orbit
Kepler-419c orbits its host star with 270% of the Sun's luminosity (2.7 ) about every 675 days (around 1.84 years) at a distance of 1.61 AU (compared to the orbital distance of Mars, which is 1.52 AU). It has a slightly eccentric orbit, with an eccentricity of 0.184. It receives about 95% of the amount of sunlight that Earth does.
Habitability
Kepler-419c resides in the circumstellar habitable zone of the parent star. The exoplanet, with a mass of 7.28 , is too massive to be rocky, and because of this the planet itself may not be habitable. However, Kepler-419c is listed as one of the candidates that may harbor potentially habitable moons, where, with the right atmospheric pressure and temperature, liquid water might exist on the surface of the moon.
Hypothetically, for a stable orbit the ratio between the moon's orbital period Ps around its primary and that of the primary around its star Pp must be < 1/9, e.g. if a planet takes 90 days to orbit its star, the maximum stable orbit for a moon of that planet is less than 10 days. Simulations suggest that a moon with an orbital period less than about 45 to 60 days will remain safely bound to a massive giant planet or brown dwarf that orbits 1 AU from a Sun-like star. In the case of Kepler-419c, this would be practically the same to have a stable orbit, albeit a bit longer, around 65 days.
Discovery
In 2009, NASA's Kepler spacecraft was completing observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In this last test, Kepler observed stars in the Kepler Input Catalog, including Kepler-419, the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Observations for the potential exoplanet candidates took place between 13 May 2009 and 17 March 2012. After observing the respective transits, the first planet, Kepler-419b, was announced.
Further investigations were made into the transit data of Kepler-419b, which was shown to be varying slightly, caused by a more distant orbiting planet. Data revealed that the responsible companion was about 7.3 times more massive than Jupiter and orbiting at a distance of 1.68 AU. The discovery was then announced on June 12, 2014.
See also
Kepler-47c
HD 69830 d
Kepler-90h
References
External links
NASA – Kepler Mission.
NASA – Kepler Discoveries – Summary Table.
NASA – Kepler-419c at The NASA Exoplanet Archive.
NASA – Kepler-419c at The Exoplanet Data Explorer.
NASA – Kepler-419c at The Extrasolar Planets Encyclopaedia.
Exoplanets discovered by the Kepler space telescope
Giant planets
Exoplanets discovered in 2014
Transiting exoplanets
Giant planets in the habitable zone
Cygnus (constellation) | Kepler-419c | [
"Astronomy"
] | 976 | [
"Cygnus (constellation)",
"Constellations"
] |
47,314,106 | https://en.wikipedia.org/wiki/Keiichi%20Itakura | is an organic chemist and a Professor in the Department of Molecular and Cellular Biology at the Beckman Research Institute at City of Hope National Medical Center.
Biography
Itakura was born in Tokyo, Japan on February 18, 1942. He obtained a PhD in Organic Chemistry at Tokyo Pharmaceutical College in 1970. He then accepted a fellowship with Saran A. Narang at the Division of Biological Sciences, National Research Council of Canada, to work on DNA synthesis.
In 1975, Itakura joined the City of Hope National Medical Center. There he was part of a team of scientists including Arthur Riggs who developed recombinant DNA technology. By 1976, the first artificial gene had been synthesized, by Har Gobind Khorana at MIT, and the possibility of synthesizing insulin through bacterial fermentation by incorporating a gene for insulin into a bacterium such as E. coli had been suggested.
Itakura and others succeeded in synthesizing a plasmid containing chemically synthesized lac operator in 1976, using a technique they called "linker technology".
In 1977, Itakura successfully synthesized the gene for somatostatin. Production of somatostatin, a hormone produced in the human brain, was not expected to be commercially significant. However, the work was considered a possible first step towards the creation of a synthetic insulin. Building on Khorana's work, Itakura developed a technique that reduced the time involved in successful synthesis from years to weeks. He then inserted the gene for somatostatin into E. coli. This was the first demonstration of a foreign gene inserted into E. coli.
By 1978 Herbert Boyer's biotechnology startup Genentech had contracted with Riggs and Itakura, and Boyer and Itakura had created a plasmid coded for human insulin. Genentech signed a joint-venture agreement with Eli Lilly and Company to develop and market the technology. Their product, Humulin, approved in 1982 by the FDA, was the first biotechnology product to be marketed. Genentech patented techniques that list Itakura and Riggs as the inventors, and are known as the Riggs-Itakura patents. As their principal organic chemist, Keiichi Itakura was essential to the success of Genentech's development of synthetic insulin. His work on recombinant DNA technology has had a significant impact in molecular biology and biochemistry.
Keiichi Itakura became a senior research scientist at City of Hope in 1980. In 1982, he formed the Department of Molecular Genetics (later the Department of Molecular and Cellular Biology). Itakura became director of City of Hope's genetics laboratory in 1989. he continues to work and teach at City of Hope.
Awards and honours
1991, Member, New York Academy of Sciences
1979, David Rumbough Scientific Award, Juvenile Diabetes Research Foundation
References
Living people
1942 births
History of biotechnology
Japanese molecular biologists | Keiichi Itakura | [
"Biology"
] | 595 | [
"History of biotechnology"
] |
47,314,514 | https://en.wikipedia.org/wiki/Interval%20edge%20coloring | In graph theory, interval edge coloring is a type of edge coloring in which edges are labeled by the integers in some interval, every integer in the interval is used by at least one edge, and at each vertex the labels that appear on incident edges form a consecutive set of distinct numbers.
History
The concept of consecutive edge-coloring was introduced with the terminology 'interval edge coloring' by Asratian and Kamalian in 1987 in their paper "Interval colorings of edges of a multigraph". Since interval edge coloring of graphs was introduced mathematicians have been investigating the existence of interval edge colorable graphs as not all graphs allow interval edge coloring. A simple family of graphs that allows interval edge coloring is complete graph of even order and a counter example of family of graphs includes complete graphs of odd order. The smallest graph that does not allow interval colorability. There are even graphs discovered with 28 vertices and maximum degree 21 that is not interval colorable by Sevast’janov though the interval colorability of graphs with maximum degree lying between four and twelve is still unknown.
proved that if a graph is interval colorable then the edge chromatic number is less than or equal to one less than its number of vertices and also noted that if G is r-regular, then G has an interval coloring if and only if G has a proper r-edge-coloring.
Interval edge coloring is investigated in regular graphs.bipartite graphs which are regular and not regular, planar graphs, among the other extensions that has been initiated in interval edge coloring.
Definition
Let G be a simple interval graph. An edge-colouring of a graph G with colours 1, 2, . . . , t is called an ""interval t-colouring"" if for each i ∈ {1, 2, . . . , t} there is at least one edge of G coloured by i and the colours of edges incident to any vertex of G are distinct and form an interval of integers. Alternatively an interval edge coloring defined as: An edge-colouring of a graph G with colours 1. . . t is an 'interval t-colouring' if all colours are used, and the colours of edges incident to each vertex of G are distinct and form an interval of integers. A graph G is "interval colourable" if G has an interval t-colouring for some positive integer t. Let N be the set of all interval colourable graphs. For a graph G ∈ N, the least and the greatest values of t for which G has an interval t-colouring are denoted by w(G) and W(G), respectively. An interval edge coloring of a graph is said to be equitable interval edge coloring if any two color classes of a graph differ by at most one.
The set of colors of edges incident with a vertex (x) is called a spectrum of (x). We say that a subset R of vertices of G has an i-property if there is a proper edge t-coloring of G which is interval over R.
A few results
If a triangle-free graph G=(V,E) has an interval t-coloring, then t ≤ |V|−1. Asratyan and Kamalian proved if G is interval color-able then χ'(G)=∆(G).
Petrosyan investigated interval colorings of complete graphs and n-dimensional cubes and showed if n ≤ t ≤ n(n+1)/2,then the n-dimensional cube Qn has an interval t-coloring. Axenovich proved that all outerplanar triangulations with more than three vertices and without separating triangles are interval colorable. If G is regular graph w(G)=∆(G) and G has an interval t-coloring for every t, w(G) ≤ t ≤ W(G).
Interval edge coloring of complete graph
Complete graph is interval colorable if and only if the number of its vertices is even.
If n=p2q, where p is odd, q is nonnegative, and 2n−1≤t≤4n−2−p−q, then the complete graph K2n has an interval t-coloring.
If F is a set of at least n edges incident to one vertex v of the complete graph K2n+1, then K2n+1−F has an interval coloring.
If F is a maximum matching of the complete graph K2n+1 with n≥2, then K2n+1−F has no interval coloring.
If n ≤ t ≤ , then the n-dimensional cube Qn has an interval t-coloring.
Interval edge coloring of bipartite graphs
For any m, n ∈ N, the complete bipartite graph Km,n is interval colorable, and
(1) w (Km,n) = m + n − gcd(m, n),
(2) W (Km,n) = m + n − 1,
(3) if w (Km,n) ≤ t ≤ W (Km,n),
then Km,n has an interval t-coloring.
If G is a bipartite graph, then χ′(G) = ∆(G).
If G ∈ N, then G[Km,n] ∈ N for any m, n ∈ N. Moreover, for any m, n ∈ N,we have
w (G[Km,n]) ≤ (w(G) + 1)(m + n) − 1 and W (G[Km,n]) ≥ (W(G) + 1)(m + n) − 1.
If G is a connected bipartite graph and G ∈ N, then W(G) ≤ diam(G) (∆(G) − 1) + 1.
Interval edge coloring of Planar graphs
Interval edge-colorings of outerplanar graphs were investigated by Giaro and Kubale and proved all the outer planar bipartite graphs are interval colorable.
IfG=G1eG2 where G1 and G2 have interval colorings in which e has an external label. Then G has an interval coloring.
Proof: Let c1 be an interval coloring of 'G1' such that e=xy gets the smallest label among edges incident to x and y.Take c1(e)=0. Consider an interval coloring c1 ofG1 where e gets the largest label among edges incident to x and y.Say,c2(e)=i. Then we construct an interval coloring c of G as c(e')=c1(e') if (e')∈E(G1) or c(e')=c2(e')-i if (e')∈ E(G1).
If G is an outerplanar graph of order at least 4 without separating triangles then it has an interval coloring.
Let G be a graph obtained by deleting some dividing edges under some interval coloring of a graph H. Then G is an interval colorable.
let H be an outerplanar triangulation with no separate triangles and let H=H1,-----Hm be decomposition with connecting edges e1,----,em-1.If G is obtained from H by deleting some connecting edges, then G has an interval coloring.
For any planar interval colorable graph G on n vertices t(G)≤(11/6)n.
Interval edge coloring of biregular bipartite graphs with small vertex degrees
A bipartite graph is (a, b)-biregular if everyvertex in one part has degree a and every vertex in the other part has degree b. It has been conjectured that all such graphs have interval colorings. Hansen proved that every bipartite graph G with ∆(G) ≤ 3 is interval colorable.
Equitable K-interval edge coloring
A k-interval edge coloring of a graph is said to be equitable k-interval edge coloring if its edge set E is partitioned into K subsets E1,E2,...,Ek such that Ei is an independent set and the condition -1 ≤ Ei ≤ Ej ≤ 1 holds for all 1 ≤i ≤k,1 ≤j ≤k. The smallest integer k for which G is equitable interval edge coloring is known as the equitable chromatic number of interval edge coloring of G and is denoted by .
Applications
Interval edge coloring has wide applications in various fields of science and scheduling.
One of the basic applications of interval edge coloring is the scheduling of the timetable for classes without clashes, in this application the class hours become the vertices and they share an edge if both share a time interval.The number of colors needed to color the edges are the number of classes needed to conduct classes without clashes. This is used in all instances where two or more events need to be organized avoiding clashes.
A similar application is found in the time scheduling of the run time of the processors.E.g. scheduling file transfers in a distributed network or scheduling diagnostic tests in a multicomputer system as well as scheduling tasks in an open shop system.Various algorithms are being developed for this purpose.
Interval edge colorability of complete graphs helps in scheduling 2n plays in a tournament such that each team plays with each other.
Many other applications are arising with the study of interval edge colorability of planar graphs and bipartite graphs.
Conjectures
For any m,n∈N, K1,m,n ∈ N if and only if gcd(m+1, n+1) = 1.
If G is a planar graph on n vertices then the maximal number of colors used in an interval coloring of G is at most (3/2)n.
An outerplanar graph obtained from an outerplanar triangulation with no separating triangles by deleting internal edges is interval colorable.
References
See also
Path coloring
Defective coloring
L(h, k)-coloring
Incidence coloring
Total coloring
Radio coloring
Acyclic coloring
Star coloring
Harmonious coloring
Sum coloring
Edge coloring
Graph coloring | Interval edge coloring | [
"Mathematics"
] | 2,090 | [
"Graph coloring",
"Mathematical relations",
"Graph theory"
] |
47,314,706 | https://en.wikipedia.org/wiki/Rate%20sensor | A rate sensor is a sensor that measures a rate (or rate of change). It may refer to:
Angular rate sensor
Rate gyro
Yaw-rate sensor
Heart rate sensor
Breath rate sensor
Oxygen transmission rate sensors
Moisture vapor transmission rate sensors
See also
Sensor based Variable Rate Application
Sensors | Rate sensor | [
"Technology",
"Engineering"
] | 59 | [
"Sensors",
"Measuring instruments"
] |
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