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https://en.wikipedia.org/wiki/Parsimonious%20reduction | In computational complexity theory and game complexity, a parsimonious reduction is a transformation from one problem to another (a reduction) that preserves the number of solutions. Informally, it is a bijection between the respective sets of solutions of two problems. A general reduction from problem to problem is a transformation that guarantees that whenever has a solution also has at least one solution and vice versa. A parsimonious reduction guarantees that for every solution of , there exists a unique solution of and vice versa.
Parsimonious reductions are commonly used in computational complexity for proving the hardness of counting problems, for counting complexity classes such as #P. Additionally, they are used in game complexity, as a way to design hard puzzles that have a unique solution, as many types of puzzles require.
Formal definition
Let be an instance of problem . A Parsimonious reduction from problem to problem is a reduction such that the number of solutions to is equal to the number of solutions to problem . If such a reduction exists, and if we have an oracle that counts the number of solutions to which is an instance of , then we can design an algorithm that counts the number of solutions to , the corresponding instance of . Consequently, if counting the number of solutions to the instances of is hard, then counting the number of solutions to must be hard as well.
Applications
Just as many-one reductions are important for proving NP-completeness, parsimonious reductions are important for proving completeness for counting complexity classes such as #P. Because parsimonious reductions preserve the property of having a unique solution, they are also used in game complexity, to show the hardness of puzzles such as sudoku where the uniqueness of the solution is an important part of the definition of the puzzle.
Specific types of parsimonious reductions may be defined by the computational complexity or other properties of the tra |
https://en.wikipedia.org/wiki/Hub%20labels | In computer science, hub labels or the hub-labelling algorithm is a method that consumes much fewer resources than the lookup table but is still extremely fast for finding the shortest paths between nodes in a graph, which may represent, for example, road networks.
This method allows at the most with two SELECT statements and the analysis of two strings to compute the shortest path between two vertices of a graph.
For a graph that is oriented like a road graph, this technique requires the prior computation of two tables from structures constructed using the method of the contraction hierarchies.
In the end, these two computed tables will have as many rows as nodes present within the graph. For each row (each node), a label will be calculated.
A label is a string containing the distance information between the current node (the node of the row) and all the other nodes that can be reached with an ascending search on the relative multi-level structure. The advantage of these distances is that they all represent the shortest paths.
So, for future queries, the search of a shortest path will start from the source on the first table and the destination on the second table, from which it will search within the labels for the common nodes with the associated distance information. Only the smallest sum of distances will be kept as the shortest path result.
References
Mathematical logic
Theoretical computer science |
https://en.wikipedia.org/wiki/Survivalcraft | Survivalcraft is a 2011 open sandbox video game developed by Marcin Igor Kalicinski under the brand Candy Rufus Games. Following early test versions, it was released on 16 November 2011 for the Windows Phone, and is also available for Android, iOS, and Microsoft Windows. The game is set on a deserted island in an open world, where the player collects resources and items that can be made into survival tools. The game has six different game modes: Survival, Challenging, Cruel, Harmless, Adventure, and Creative. of which the first four involve the player gathering necessary resources to stay alive. The Creative mode gives the player unlimited items and health. And the Adventure mode is used for quest maps and parkours.
Kalicinski was inspired by Minecraft, and originally only worked on the game for fun, with his son as the sole pre-release tester. The game was compared to Minecraft by various reviews, with most reviews stating that the game is either better than or supplements its source of inspiration. The game became one of the most downloaded games for Windows Phone and iPad in 2013 and 2014. The sequel Survivalcraft 2 followed in December 2016, and allows players to create their own blocks.
Gameplay
Survivalcraft is a three-dimensional (3D) sandbox game that is set on a deserted island. The game begins with the player generating an open world, based on parameters such as the average temperature and humidity. After setting up the world, the player character is shown marooned on an island, as the crew on a nearby ship announces they will not return for them.
After the dialogue ends, the player is pushed by the necessity to collect resources and items to survive. The player may start by cutting down a tree to obtain timber and, in turn, creating a workbench, which can then be used to create more items and blocks. The items that could be crafted in the workbench, as well as the prerequired items and the methods to craft them, could be seen in the Recipaedia. The p |
https://en.wikipedia.org/wiki/Wireless%20onion%20router | A wireless onion router is a router that uses Tor to connect securely to a network. The onion router allows the user to connect to the internet anonymously creating an anonymous connection. Tor works using an overlaid network which is free throughout the world, this overlay network is created by using numerous relay points created using volunteer which helps the user hide personal information behind layers of encrypted data like layers of an onion. Routers are being created using Raspberry Pi adding a wireless module or using its own inbuilt wireless module in the later versions.
This router provides encryption at the seventh layer (application layer) of the OSI model, which makes it transparent encryption, the user does not have to think about how the data will be sent or received. The encrypted data includes the destination and origin IP address of the data and the current relay point only knows the previous and the next hop of the encrypted packet. These relay points are selected in a random order and can only decrypt a single layer before forwarding it to the next hop where is the procedure is followed unless it is the destination point.
Applications
A wireless router which can use the onion router network can be used to keep the user safe from hackers or network sniffers. The data captured by them won't make any sense as it will only look like messed up text. These are small and handy which will give the user a freedom to carry this tool and connect to the network from anywhere. This setup does not require installation of Tor browser on the work station. Whistle blowers and NGO workers use this network to pass information or to talk to their family without disclosing any information. The applications of wireless onion router are common to a normal router, it provides access that allows it to be placed at a site and users can get connected.
Tor can be used in security focused Operating Systems, messengers, browsers. These can be anonymised using Tor network.
|
https://en.wikipedia.org/wiki/Hand%20in%20Hand%3A%20A%20Benefit%20for%20Hurricane%20Relief | Hand in Hand: A Benefit for Hurricane Relief was a one-hour, commercial-free benefit concert television special that aired simulcast in the United States on September 12, 2017, at 8 p.m. ET/CT live from New York City, Nashville, San Antonio, and Los Angeles and tape delayed MT and PT.
During the hour it was on the air, the special raised $14 million for the relief efforts from the aftermath of Hurricane Harvey and Hurricane Irma. By evening's end the total was up to $44 million.
Organizations benefitting the relief include the United Way of Greater Houston, Rebuild Texas Fund, ASPCA, Habitat for Humanity, Best Friends, Direct Relief, Save the Children, Feeding Texas, Feeding Florida, and the Mayor's Fund for Hurricane Harvey Relief. On October 17, 2017, it was announced that benefits would now also go to the victims of Hurricane Maria, which occurred the week after the concert. The Hand in Hand Fund is managed by Comic Relief, Inc.
The concert was produced Scooter Braun and SB Projects, the same team who organized the One Love Manchester benefit with Ariana Grande.
To date, the benefit has raised over $55 million in donations.
Musical performances
"Lean on Me" – Stevie Wonder with Victoria White, Marquist Taylor and Houston gospel choir
"Stand by Me" – Usher and Blake Shelton
"Hallelujah" (bilingual in the John Cale arrangement) – Tori Kelly and Luis Fonsi
"Mercy" – Dave Matthews
"With a Little Help From My Friends" (in the Joe Cocker arrangement) – Demi Lovato, Brad Paisley, Darius Rucker, and CeCe Winans
"Texas" and "I Believe" – George Strait, Miranda Lambert, Chris Stapleton, Lyle Lovett, and Robert Earl Keen
Spoken segments
Beyoncé
Justin Bieber
Cher
George Clooney
Billy Crystal
Robert De Niro
Leonardo DiCaprio
Jimmy Fallon
Jamie Foxx
Jennifer Garner
Selena Gomez
Tom Hanks
Taraji P. Henson
Dwayne Johnson
Nicole Kidman
Matthew McConaughey
Dennis Quaid
Julia Roberts
Will Smith
Gwen Stefani
Barbra Streisand
Justin Timberlake
Sofía Vergara
Kerry Washin |
https://en.wikipedia.org/wiki/High%20frequency%20data | High frequency data refers to time-series data collected at an extremely fine scale. As a result of advanced computational power in recent decades, high frequency data can be accurately collected at an efficient rate for analysis. Largely used in financial analysis and in high frequency trading, high frequency data provides intraday observations that can be used to understand market behaviors, dynamics, and micro-structures.
High frequency data collections were originally formulated by massing tick-by-tick market data, by which each single 'event' (transaction, quote, price movement, etc.) is characterized by a 'tick', or one logical unit of information. Due to the large amounts of ticks in a single day, high frequency data collections generally contain a large amount of data, allowing high statistical precision. High frequency observations across one day of a liquid market can equal the amount of daily data collected in 30 years.
Use
Due to the introduction of electronic forms of trading and Internet-based data providers, high frequency data has become much more accessible and can allow one to follow price formation in real-time. This has resulted in a large new area of research in the high frequency data field, where academics and researchers use the characteristics of high frequency data to develop adequate models for predicting future market movements and risks. Model predictions cover a wide range of market behaviors including volume, volatility, price movement, and placement optimization.
There is an ongoing interest in both regulatory agencies and academia surrounding transaction data and limit order book data, of which greater implications of trade and market behaviors as well as market outcomes and dynamics can be assessed using high frequency data models. Regulatory agencies take a large interest in these models due to the fact that liquidity and price risks are not fully understood in terms of newer forms of automated trading applications.
High |
https://en.wikipedia.org/wiki/Co-Hopfian%20group | In the mathematical subject of group theory, a co-Hopfian group is a group that is not isomorphic to any of its proper subgroups. The notion is dual to that of a Hopfian group, named after Heinz Hopf.
Formal definition
A group G is called co-Hopfian if whenever is an injective group homomorphism then is surjective, that is .
Examples and non-examples
Every finite group G is co-Hopfian.
The infinite cyclic group is not co-Hopfian since is an injective but non-surjective homomorphism.
The additive group of real numbers is not co-Hopfian, since is an infinite-dimensional vector space over and therefore, as a group .
The additive group of rational numbers and the quotient group are co-Hopfian.
The multiplicative group of nonzero rational numbers is not co-Hopfian, since the map is an injective but non-surjective homomorphism. In the same way, the group of positive rational numbers is not co-Hopfian.
The multiplicative group of nonzero complex numbers is not co-Hopfian.
For every the free abelian group is not co-Hopfian.
For every the free group is not co-Hopfian.
There exists a finitely generated non-elementary (that is, not virtually cyclic) virtually free group which is co-Hopfian. Thus a subgroup of finite index in a finitely generated co-Hopfian group need not be co-Hopfian, and being co-Hopfian is not a quasi-isometry invariant for finitely generated groups.
Baumslag–Solitar groups , where , are not co-Hopfian.
If G is the fundamental group of a closed aspherical manifold with nonzero Euler characteristic (or with nonzero simplicial volume or nonzero L2-Betti number), then G is co-Hopfian.
If G is the fundamental group of a closed connected oriented irreducible 3-manifold M then G is co-Hopfian if and only if no finite cover of M is a torus bundle over the circle or the product of a circle and a closed surface.
If G is an irreducible lattice in a real semi-simple Lie group and G is not a virtually free group then G is co-Hopfian. E.g. this |
https://en.wikipedia.org/wiki/Female%20education%20in%20STEM | Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and |
https://en.wikipedia.org/wiki/Icelandic%20Junior%20College%20Mathematics%20Competition | Icelandic Junior College Mathematics Competition () is an annual mathematical olympiad first held in the winter of 1984–1985. It is hosted by the Icelandic Mathematical Organization () and the Natural Sciences's Teacher Association, and the largest competition of its kind in the country. Its goals include increasing the interest of Icelandic secondary school students towards mathematics, and other fields built on a mathematical foundation.
The contest is held in two parts every winter. First, a qualifier held in October of every year on two difficulty levels; upper level, and lower level. The lower level is intended for first year secondary school students, and the upper level for older students. Those who do well in the qualifier are invited to the final competition, held in March.
Alongside honours and awards, the top students are selected to perform in various mathematical olympiads, including the Baltic Way, the Nordic Mathematical Contest, and the International Mathematical Olympiad.
References
Mathematics competitions
International Mathematical Olympiad
Recurring events established in 1984 |
https://en.wikipedia.org/wiki/Zetron | Zetron, Inc. is an American company that manufactures integrated communications systems. Founded in 1980, formerly a subsidiary of JVCKenwood, in May 2021 it was purchased by Codan Communications. Its products are for use by Emergency and Public Safety Agencies (Fire, Ambulance and Police), Utilities and Transportation Companies.
Products
Radio Dispatch Systems
E-9-1-1 Call Taking Systems
Fire station alerting and Dispatch Systems
CAD and GIS Mapping System - Computer-aided Dispatch (CAD) & Geographic Information System (GIS) Systems
Specialized integrated communications
Paging Systems
History
1980: Zetron is founded by Milt Zeutschel and John Reece.
1981: Introduces paging products for volunteer fire departments (CE-1000).
1987: Introduces Series 4000, the first user programmable microprocessor-based radio dispatch console.
1990: Opens European office.
1996: Introduces the first integrated radio dispatch and 9-1-1 call taking solution.
2000: Zetron acquired the ACOM Business Unit from Plessey Asia Pacific Pty Ltd
2001: The Advanced Communication System (Acom) is introduced, expanding to large-scaled dispatch center capability.
2002: ACOM based VSCS is fully commissioned as the communications component of The Australian Advanced Air Traffic System
2004: IP-based interface is delivered between Acom and M/A-Com's OpenSky.
2007: Acquired by the Japanese company Kenwood Corporation (now JVCKenwood).
2007: Zetron becomes the first vendor to support the P25 CSSI Console interface.
2008: New IP-based Fire Station Alerting system begins shipping.
2017: Established the strategic partnership with Harris Corporation company for emergency dispatch console system.
2020: Celebrates 40 years in business.
2021: Purchased by Codan Communications, the communications subsidiary of the Codan Group.
Notes
Radio technology
Amateur radio companies
Companies based in Redmond, Washington
Electronics companies established in 1980
Electronics companies of the |
https://en.wikipedia.org/wiki/.cloud | .cloud is a generic top-level domain (gTLD) delegated by ICANN. It is managed by the Italian company Aruba PEC SpA, a wholly owned subsidiary of the same Aruba S.p.A., one of the largest distributors of Hostings and Providers in Europe.
The back-end services are provided by ARI Registry Services. The proposed application succeeded and was delegated to the DNS root zone on 26 Jun 2015.
The .cloud domain doesn't have any restriction.
See also
List of Internet top-level domains
References
External links
.cloud – ICANNWiki
Cloud computing
Generic top-level domains |
https://en.wikipedia.org/wiki/Post-mortem%20privacy | Post-mortem privacy is a person's ability to control the dissemination of personal information after death. An individual's reputation and dignity after death is also subject to post-mortem privacy protections. In the US, no federal laws specifically extend post-mortem privacy protection. At the state level, privacy laws pertaining to the deceased vary significantly, but in general do not extend any clear rights of privacy beyond property rights. The relative lack of acknowledgment of post-mortem privacy rights has sparked controversy, as rapid technological advancements have resulted in increased amounts of personal information stored and shared online.
Law
United States
Under common law, the right to privacy is considered a personal right, meaning it applies only to the living and, consequently, does not recognize the privacy interests of the deceased. Because of this, defamation and privacy torts that are used to prevent unjust damage to individuals' reputations cannot be extended post-mortem. For example, a family cannot file suit for invasion of privacy on behalf of a deceased relative as a personal right; it can only be exerted by the person whose rights are being infringed upon. In addition, the deceased do not qualify for privacy protections held in constitutional and statutory rights, such as those noted in the Fourth and Fourteenth Amendments. Judicial justification for the termination of privacy rights at death is centered on two main points: firstly, the deceased can no longer be active agents, and secondly, the deceased are incapable of being harmed by invasion of privacy or defamation. The only clear extension of postmortem privacy rights under federal law are those pertaining to property. Via Will, private property and some personal information can be passed on to heirs in accordance with the decedent's wishes.
Most post-mortem privacy protection occurs on the state level. Thus, legislation and the degree of protection varies widely from state t |
https://en.wikipedia.org/wiki/Klexikon | Klexikon is a German online encyclopedia for children aged six to twelve years. It was launched in December 2014. The name Klexikon is a portmanteau combining the two German words Kinder [children] and Lexikon [encyclopedia]. Like its role model Wikipedia, the site was created as a wiki using the MediaWiki software. The text content is available under a Creative Commons By Attribution Share-alike version 3.0 licence while free media is taken from Wikimedia Commons. Special rules were implemented to ensure that all content is suitable for children. Moreover, all editors are required to register with an email address.
History
The Klexikon encyclopedia was founded by journalist Michael Schulte and historian Ziko van Dijk, who was the chairman of Wikimedia Netherlands from 2011 to 2014. The website is owned by non-profit association Zentrale für Unterrichtsmedien im Internet [online educational media centre] which also hosts other types of Wikis.
One year after its launch, Klexikon consisted of 1,000 articles and 1,500 articles had been created after two years. The Klexikon community of editors decides per consensus which articles should be created next so as to assure that the most important topics, school subjects and areas of interest of children are covered.
Klexikon was supported by Wikimedia Germany in creating the concept of an online encyclopedia for children. The concept was then refined by cooperating with Technical University of Dortmund and Technical University of Cologne.
Reception
The German Federal Ministry of Family Affairs, Senior Citizens, Women and Youth considers the site a "useful" children's encyclopedia. According to the voluntary self control association of German television, Klexikon's advantage is that unlike Wikipedia it is specifically written for children. The Austrian School Portal wrote that Klexikon was a "great work of reference" which provided content that was specifically balanced for children. The Merz magazine noted that Klexikon |
https://en.wikipedia.org/wiki/Landau%E2%80%93Levich%20problem | In fluid dynamics, Landau–Levich flow or the Landau–Levich problem describes the flow created by a moving plate which is pulled out of a liquid surface. Landau–Levich flow finds many applications in thin film coating. The solution to the problem was described by Lev Landau and Veniamin Levich in 1942. The problem assumes that the plate is dragged out of the liquid slowly, so that the three major forces which are in balance are viscous force, the force due to gravity, and the force due to surface tension.
Problem
Landau and Levich split the entire flow regime into two regimes, a lower regime and an upper regime. In the lower regime closer to the liquid surface, the flow is assumed to be static, leading to the problem of the Young–Laplace equation (a static meniscus). In the upper region far away from the liquid surface, the thickness of the liquid layer attaching to the plate is very small and also the since the velocity of the plate is small, this regime comes under the approximation of lubrication theory. The solution of these two problems are then matched using method of matched asymptotic expansions.
References
Flow regimes
Fluid dynamics
Thin film deposition
Lev Landau |
https://en.wikipedia.org/wiki/Fundamental%20groupoid | In algebraic topology, the fundamental groupoid is a certain topological invariant of a topological space. It can be viewed as an extension of the more widely-known fundamental group; as such, it captures information about the homotopy type of a topological space. In terms of category theory, the fundamental groupoid is a certain functor from the category of topological spaces to the category of groupoids.
Definition
Let be a topological space. Consider the equivalence relation on continuous paths in in which two continuous paths are equivalent if they are homotopic with fixed endpoints. The fundamental groupoid assigns to each ordered pair of points in the collection of equivalence classes of continuous paths from to . More generally, the fundamental groupoid of on a set restricts the fundamental groupoid to the points which lie in both and . This allows for a generalisation of the Van Kampen theorem using two base points to compute the fundamental group of the circle.
As suggested by its name, the fundamental groupoid of naturally has the structure of a groupoid. In particular, it forms a category; the objects are taken to be the points of and the collection of morphisms from to is the collection of equivalence classes given above. The fact that this satisfies the definition of a category amounts to the standard fact that the equivalence class of the concatenation of two paths only depends on the equivalence classes of the individual paths. Likewise, the fact that this category is a groupoid, which asserts that every morphism is invertible, amounts to the standard fact that one can reverse the orientation of a path, and the equivalence class of the resulting concatenation contains the constant path.
Note that the fundamental groupoid assigns, to the ordered pair , the fundamental group of based at .
Basic properties
Given a topological space , the path-connected components of are naturally encoded in its fundamental groupoid; the observation is |
https://en.wikipedia.org/wiki/Intel%20Ultra%20Path%20Interconnect | The Intel Ultra Path Interconnect (UPI) is a point-to-point processor interconnect developed by Intel which replaced the Intel QuickPath Interconnect (QPI) in Xeon Skylake-SP platforms starting in 2017.
Interconnect
UPI is a low-latency coherent interconnect for scalable multiprocessor systems with a shared address space. It uses a directory-based home snoop coherency protocol with a transfer speed of up to 10.4 GT/s. Supporting processors typically have two or three UPI links.
Comparing to QPI, it improves power efficiency with a new low-power state, improves transfer efficiency with a new packetization format, and improves scalability with protocol layer that does not require preallocation of resources.
UPI only supports directory-based coherency, unlike previous QPI processors which supported multiple snoop modes (no snoop, early snoop, home snoop, and directory).
A combined caching and home agent (CHA) handles resolution of coherency across multiple processors, as well as snoop requests from processor cores and local and remote agents. Separate physical CHAs are placed within each processor core and last level cache (LLC) bank to improve scalability according to the number of cores, memory controllers, or the sub-NUMA clustering mode. The address space is interleaved across different CHAs, which act like a single logical agent.
See also
HyperTransport
Front-side bus
References
External links
Intel® Xeon® Processor Scalable Family Technical Overview
Computer buses
UltraPath Interconnect
Serial buses |
https://en.wikipedia.org/wiki/Coherent%20algebra | A coherent algebra is an algebra of complex square matrices that is closed under ordinary matrix multiplication, Schur product, transposition, and contains both the identity matrix and the all-ones matrix .
Definitions
A subspace of is said to be a coherent algebra of order if:
.
for all .
and for all .
A coherent algebra is said to be:
Homogeneous if every matrix in has a constant diagonal.
Commutative if is commutative with respect to ordinary matrix multiplication.
Symmetric if every matrix in is symmetric.
The set of Schur-primitive matrices in a coherent algebra is defined as .
Dually, the set of primitive matrices in a coherent algebra is defined as .
Examples
The centralizer of a group of permutation matrices is a coherent algebra, i.e. is a coherent algebra of order if for a group of permutation matrices. Additionally, the centralizer of the group of permutation matrices representing the automorphism group of a graph is homogeneous if and only if is vertex-transitive.
The span of the set of matrices relating pairs of elements lying in the same orbit of a diagonal action of a finite group on a finite set is a coherent algebra, i.e. where is defined as for all of a finite set acted on by a finite group .
The span of a regular representation of a finite group as a group of permutation matrices over is a coherent algebra.
Properties
The intersection of a set of coherent algebras of order is a coherent algebra.
The tensor product of coherent algebras is a coherent algebra, i.e. if and are coherent algebras.
The symmetrization of a commutative coherent algebra is a coherent algebra.
If is a coherent algebra, then for all , , and if is homogeneous.
Dually, if is a commutative coherent algebra (of order ), then for all , , and as well.
Every symmetric coherent algebra is commutative, and every commutative coherent algebra is homogeneous.
A coherent algebra is commutative if and only if it is the Bose– |
https://en.wikipedia.org/wiki/Single%20colour%20reflectometry | Single colour reflectometry (SCORE), formerly known as imaging Reflectometric Interferometry (iRIf) and 1-lambda Reflectometry, is a physical method based on interference of monochromatic light at thin films, which is used to investigate (bio-)molecular interactions. The obtained binding curves using SCORE provide detailed information on kinetics and thermodynamics of the observed interaction(s) as well as on concentrations of the used analytes. These data can be relevant for pharmaceutical screening and drug design, biosensors and other biomedical applications, diagnostics, and cell-based assays.
Principle
The underlying principle corresponds to that of the Fabry-Pérot interferometer, which is also the underlying principle for the white-light interferometry.
Realisation / setup
Monochromatic light is illuminated vertically on the rear side of a transparent multi-layer substrate. The partial beams of the monochromatic light are transmitted and reflected at each interphase of the multi-layer system. Superimposition of the reflected beams result in destructive or constructive interference (depending on wavelength of the used light and the used substrate/multi-layer system materials) that can be detected in an intensity change of the reflected light using a photodiode, CCD, or CMOS element.
The sensitive layer on top of the multi-layer system can be (bio-)chemically modified with receptor molecules, e.g. antibodies. Binding of specific ligands to the immobilised receptor molecules results in a change refractive index n and physical thickness d of the sensitive layer. The product of n and d results in the optical thickness (n*d) of the sensitive layer.
Monitoring the change of the reflected intensity of the used light over time results in binding curves that provide information on:
concentration of used ligand
binding kinetics (association and dissociation rate constants) between receptor and ligand
binding strength (affinity) between receptor and ligand
speci |
https://en.wikipedia.org/wiki/Wuest%20type%20herringbone%20gear | A Wuest type herringbone gear, invented by Swiss engineer Caspar Wüst-Kunz in early 1900s, is a special type of herringbone gear wherein "the teeth on opposite sides of the center line are staggered by an amount equal to one half the circular pitch". By having the teeth of two sides staggered, the gear wears more evenly at the slight cost of strength.
References
Gears |
https://en.wikipedia.org/wiki/George%20Szpiro | George Geza Szpiro (born 18 February 1950 in Vienna) is an Israeli–Swiss author, journalist, and mathematician. He has written articles and books on popular mathematics and related topics.
Life and career
Szpiro was born in Vienna in 1950, and moved to Zug, Switzerland, in 1961. He obtained a master's degree in mathematics and physics from ETH Zurich. He also obtained an MBA from Stanford University, in 1975. Afterward, he worked as a management consultant at McKinsey & Company. In 1984, he obtained a Ph.D. in mathematical economics from Hebrew University.
Szpiro was an assistant professor at the Wharton School of the University of Pennsylvania, during 1984–1986. He was a lecturer in mathematical economics at Hebrew University, during 1986–1992. He also taught at the University of Zurich. He has published research papers related to mathematics, finance, and statistics.
Since 1986, Szpiro has worked as a journalist at Neue Zürcher Zeitung. At NZZ, he has been the Israel correspondent and mathematics columnist. For his mathematics columns, Szpiro was awarded the Prix Média by the Swiss Academy of Natural Sciences, in 2003. He was also awarded the Media Prize by the German Mathematical Society, in 2006. Beside writing for NZZ, he has also written non-research mathematics columns for journals such as Nature and Notices of the American Mathematical Society.
Szpiro married in 1979. He and his wife, Fortuna, have three children.
Books
Kepler's Conjecture: How Some of the Greatest Minds in History Helped Solve One of the Oldest Math Problems in the World (John Wiley & Sons, 2003)
The Secret Life of Numbers: 50 Easy Pieces on How Mathematicians Work and Think (Joseph Henry Press, 2006)
Poincaré's Prize: The Hundred-Year Quest to Solve One of Math's Greatest Puzzles (Dutton, 2007)
Numbers Rule: The Vexing Mathematics of Democracy, from Plato to the Present (Princeton University Press, 2010)
A Mathematical Medley: Fifty Easy Pieces on Mathematics (American Mathe |
https://en.wikipedia.org/wiki/Seriation%20%28statistics%29 | In combinatorial data analysis, seriation is the process of finding an arrangement of all objects in a set, in a linear order, given a loss function. The main goal is exploratory, to reveal structural information.
References
Combinatorics
Data analysis |
https://en.wikipedia.org/wiki/Echinobase | Echinobase is a Model Organism Database (MOD). It supports the international research community by providing a centralized, integrated web based resource to access the diverse and rich, functional genomics data of echinoderm evolution, development and gene regulatory networks.
Genomic research data and tools are available for searching, browsing and bioinformatic analysis of genomes, genes, and transcripts.
Echinobase provides a critical data sharing infrastructure for other NIH-funded projects and enhances the availability and visibility of echinoderm data to the broader biomedical research community.
Supported Species
Echinobase offers two levels of integration for supported echinoderm species. Full support includes full genome integration in the database, including gene pages, as well as availability of the genomes to BLAST, browsing via JBrowse, and genome download. Partial support provides BLAST, JBrowse, and download options, but no gene page integration.
Current level one supported species (at various stages of integration) are:
Strongylocentrotus purpuratus (Purple sea urchin)
Patiria miniata (Bat star)
Lytechinus variegatus (Green variegated sea urchin)
Acanthaster planci (Crown-of-thorns starfish)
Current level two supported species (at various stages of integration) are:
Lytechinus pictus (painted urchin)
Anneissia japonica (Feather star, a crinoid)
Asterias rubens (Sugar star)
Software, Hardware and Platform
Echinobase runs in a cloud environment. Its virtual machines are running in a VMware vSphere environment on two servers, with automatic load balancing and fault tolerance. Its software uses Java, JSP, JavaScript, AJAX, XML, and CSS. It also uses Apache Tomcat and the IBM Db2 database. Echinobase is developed in tandem with Xenbase.
Functional Genomics
Echinobase is a resource for genomics research that is organized by gene models and represented using gene pages. Each gene page has a tremendous amount of gene specific information. |
https://en.wikipedia.org/wiki/Data%20shadow | Data shadows refer to the information that a person leaves behind unintentionally while taking part in daily activities such as checking their e-mails, scrolling through social media or even by using their debit or credit card.
The term data shadow was coined in 1972 by Kerstin Anér, a member of the Swedish legislature.
The generated information has the potential to create a vastly detailed record of an individual's daily trails, which includes the individual's thoughts and interests, whom they communicate with, information about the organizations with which they work or interact with and so forth. This information can be dispersed to a dozen organizations and servers depending on their use. Along with Individuals, the activities of institutions and organizations are also tracked. Data Shadows are closely linked with data footprints, which are defined as the data that has been left behind by the individual themselves through various activities such as online activities, communication information, and transactions.
In a chapter for the book Geography and Technology, researcher Matthew Zook and his co-authors note that data shadows have come as a result of people becoming "digital individuals" and that these shadows are continually evolving and changing. They are used to model and predict political opinions, and make inferences about a person's political values or susceptibility to advertising.
Digital footprint
The data or digital footprints are obtained from monitoring and tracking individuals’ digital activities. Digital footprints provide a drive for companies such as Facebook and Google to invest in obtaining data generated from these footprints, in order to be sold to marketers. As illustrated by Bodle, users are willing to give up their information to companies they trust.
Although collecting individuals’ data raises several ethical concerns, it can be valuable for the healthcare data analytics and new health services. For instance, access to such data ca |
https://en.wikipedia.org/wiki/Cancelling%20out | Cancelling out is a mathematical process used for removing subexpressions from a mathematical expression, when this removal does not change the meaning or the value of the expression because the subexpressions have equal and opposing effects. For example, a fraction is put in lowest terms by cancelling out the common factors of the numerator and the denominator. As another example, if a×b=a×c, then the multiplicative term a can be canceled out if a≠0, resulting in the equivalent expression b=c; this is equivalent to dividing through by a.
Cancelling
If the subexpressions are not identical, then it may still be possible to cancel them out partly. For example, in the simple equation 3 + 2y = 8y, both sides actually contain 2y (because 8y is the same as 2y + 6y). Therefore, the 2y on both sides can be cancelled out, leaving 3 = 6y, or y = 0.5. This is equivalent to subtracting 2y from both sides.
At times, cancelling out can introduce limited changes or extra solutions to an equation. For example, given the inequality ab ≥ 3b, it looks like the b on both sides can be cancelled out to give a ≥ 3 as the solution. But cancelling 'naively' like this, will mean we don't get all the solutions (sets of (a, b) satisfying the inequality). This is because if b were a negative number then dividing by a negative would change the ≥ relationship into a ≤ relationship. For example, although 2 is more than 1, –2 is less than –1. Also if b were zero then zero times anything is zero and cancelling out would mean dividing by zero in that case which cannot be done. So in fact, while cancelling works, cancelling out correctly will lead us to three sets of solutions, not just one we thought we had. It will also tell us that our 'naive' solution is only a solution in some cases, not all cases:
If b > 0: we can cancel out to get a ≥ 3.
If b < 0: then cancelling out gives a ≤ 3 instead, because we would have to reverse the relationship in this case.
If b is exactly zero: then the equa |
https://en.wikipedia.org/wiki/Reinforcement%20%28speciation%29 | Reinforcement is a process of speciation where natural selection increases the reproductive isolation (further divided to pre-zygotic isolation and post-zygotic isolation) between two populations of species. This occurs as a result of selection acting against the production of hybrid individuals of low fitness. The idea was originally developed by Alfred Russel Wallace and is sometimes referred to as the Wallace effect. The modern concept of reinforcement originates from Theodosius Dobzhansky. He envisioned a species separated allopatrically, where during secondary contact the two populations mate, producing hybrids with lower fitness. Natural selection results from the hybrid's inability to produce viable offspring; thus members of one species who do not mate with members of the other have greater reproductive success. This favors the evolution of greater prezygotic isolation (differences in behavior or biology that inhibit formation of hybrid zygotes). Reinforcement is one of the few cases in which selection can favor an increase in prezygotic isolation, influencing the process of speciation directly. This aspect has been particularly appealing among evolutionary biologists.
The support for reinforcement has fluctuated since its inception, and terminological confusion and differences in usage over history have led to multiple meanings and complications. Various objections have been raised by evolutionary biologists as to the plausibility of its occurrence. Since the 1990s, data from theory, experiments, and nature have overcome many of the past objections, rendering reinforcement widely accepted, though its prevalence in nature remains unknown.
Numerous models have been developed to understand its operation in nature, most relying on several facets: genetics, population structures, influences of selection, and mating behaviors. Empirical support for reinforcement exists, both in the laboratory and in nature. Documented examples are found in a wide range of or |
https://en.wikipedia.org/wiki/Secondary%20contact | Secondary contact is the process in which two allopatricaly distributed populations of a species are geographically reunited. This contact allows for the potential for the exchange of genes, dependent on how reproductively isolated the two populations have become. There are several primary outcomes of secondary contact: extinction of one species, fusion of the two populations back into one, reinforcement, the formation of a hybrid zone, and the formation of a new species through hybrid speciation.
Extinction
One of the two populations may go extinct due to competitive exclusion after secondary contact. This tends to happen when the two populations have strong reproductive isolation and significant overlap in their niche. A possible way to prevent extinction is if there is an advantage to being rare. For example, sexual imprinting and male-male competition may prevent extinction.
The population that goes extinct may leave behind some of its genes in the surviving population if they hybridize. For example, the secondary contact between Homo sapiens and Neanderthals, as well as the Denisovans, left traces of their genes in modern human. However, if hybridization is so common that the resulting population received significant amount of genetic contribution from both populations, the result should be considered a fusion.
Fusion
The two populations may fuse back into one population. This tends to occur when there is little to no reproductive isolation between the two. During the process of fusion a hybrid zone may occur. This is sometimes called introgressive hybridization or reverse speciation. Concerns have been raised that the homogenizing of the environment may contribute to more and more fusion, leading to the loss of biodiversity.
Hybrid zones
A hybrid zone may appear during secondary contact, meaning there would be an area where the two populations cohabitate and produce hybrids, often arranged in a cline. The width of the zone may vary from tens of meters |
https://en.wikipedia.org/wiki/Stride%20%28software%29 | Stride was a cloud-based team business communication and collaboration tool, launched by Atlassian on 7 September 2017 to replace the cloud-based version of HipChat. Stride software was available to download onto computers running Windows, Mac or Linux, as well as Android, iOS smartphones, and tablets. Stride was bought by Atlassian's competitor Slack Technologies and was discontinued on February 15, 2019.
The features of Stride include chat rooms, one-on-one messaging, file sharing, 5 GB of file storage, group voice and video calling, built-in collaboration tools, and up to 25,000 of searchable message history. Premium features include unlimited file storage, users, group chat rooms, file sharing and storage, apps, and history retention. The premium version, priced at $3/user/month, also includes advanced meeting functionality like group screen sharing, remote desktop control, and dial-in/dial-out capabilities. Stride offered integrations with Atlassian's other products as well as other third-party applications listed in the Atlassian Marketplace, such as GitHub, Giphy, Stand-Bot and Google Calendar.
Stride offered additional features beyond messaging to improve efficiency and productivity. It aimed to reduce collaboration noise by introducing a "focus" mode, and eliminates the divisions between text chat, voice meetings, and videoconferencing, by simplifying transitioning between these modes in the same channel.
On July 26, 2018, Atlassian announced that HipChat and Stride would be discontinued February 15, 2019, and that it had reached a deal to sell their intellectual property to Slack. Slack will pay an undisclosed amount over three years to assume the user bases of the services, and Atlassian will take a minority investment in Slack. The companies also announced a commitment to work on integration of Slack with Atlassian services.
See also
List of collaborative software
References
External links
Web applications
Chat websites
Instant messaging
At |
https://en.wikipedia.org/wiki/Jaswant%20Singh%E2%80%93Bhattacharji%20stain | Jaswant Singh–Bhattacharji stain, commonly referred to as JSB stain, is a rapid staining method for detection of malaria. It is useful for the diagnosis of malaria in thick smear samples of blood. The JSB stain is commonly used throughout India, but rarely used in other countries.
Composition
The JSB stain consists of two solutions which are used in sequence to stain various parts of the sample. The first solution consists of methylene blue, potassium dichromate, and sulfuric acid diluted in water. This solution is heated for several hours to oxidize the methylene blue. The second solution is eosin dissolved in water.
See also
Giemsa stain
Wright stain
References
Microscopy
Microbiology techniques
Laboratory techniques
Histopathology
Histotechnology
Staining dyes
Staining
Romanowsky stains |
https://en.wikipedia.org/wiki/Fastly | Fastly is an American cloud computing services provider. It describes its network as an edge cloud platform, which is designed to help developers extend their core cloud infrastructure to the edge of the network, closer to users. The Fastly edge cloud platform includes their content delivery network (CDN), image optimization, video and streaming, cloud security, and load balancing services. Fastly's cloud security services include denial-of-service attack protection, bot mitigation, and a web application firewall. Fastly's web application firewall uses the Open Web Application Security Project ModSecurity Core Rule Set alongside its own ruleset. The company follows up on unsolicited emails with VOIP phone calls spoofing local phone numbers.
The Fastly platform is built on top of Varnish. As of December 2021, Fastly transfers 50–100 Tbps of data.
History
Fastly was founded in 2011 by the Swedish-American entrepreneur Artur Bergman, previously chief technical officer at Wikia (now Fandom). In June 2013, Fastly raised $10 million in Series B funding. In April 2014, the company announced that it had acquired CDN Sumo, a CDN add-on for Heroku. In September 2014, Fastly raised a further $40 million in Series C funding, followed by a $75 million Series D round in August 2015.
In September 2015, Google partnered with Fastly and other content delivery network providers to offer services to its users. In April 2017, Fastly launched its edge cloud platform along with image optimization, load balancing, and a web application firewall.
Fastly raised $50 million in funding in April 2017, and another $40 million in July 2018. The company filed for an initial public offering (IPO) in April 2019 and debuted on the New York Stock Exchange on May 17, 2019. In February 2020, Bergman stepped down as CEO and assumed the role of chief architect and executive chairperson; Joshua Bixby took over the CEO role.
In August 2020, Fastly announced it was acquiring cybersecurity company Signa |
https://en.wikipedia.org/wiki/Precious%20Plastic | Precious Plastic is an open hardware plastic recycling project and is a type of open source digital commons project. The project was started in 2013 by Dave Hakkens and is now in its fourth iteration. It relies on a series of machines and tools which grind, melt, and inject recycled plastic, allowing for the creation of new products out of recycled plastic on a small scale.
History
In 2012, Dave Hakkens started working on Precious Plastic as a part of his studies at the Design Academy in Eindhoven. The project was released in 2013 as Version 1.0.
The work on version 2 was started in 2015 and was released in March 2016. In 2016, Precious Plastic also created a marketplace called Bazar for selling machines and products targeted to DIY designers to recycle plastic.
The team started working on version 3.0 from early 2017 and was launched in October 2017.
In May 2018, Precious Plastic received the Famae award of €300,000 to further develop the project. The city of Eindhoven also provided them a big workspace free of charge. In October 2018, Precious Plastic project officially opened its doors at the VDMA building in Eindhoven. The work on Version 4.0 was started in September 2018.
In 2019 Hakkens and Precious Plastic were involved in disagreement over whether to burn or recycle plastics collected from the oceans.
The version 4, which includes business models and starter kits for creating recycling systems, was announced in January 2020.
In December 2020, One Army was launched as an umbrella organization for a growing collection of projects including Precious Plastic, Project Kamp, PhoneBloks, Fixing Fashion, and Story Hopper.
Fixing Fashion was launched in March 2021.
Description
Precious Plastic is an open hardware plastic recycling project and is a type of open source digital commons project. It relies on a series of machines and tools which grind, melt, and inject recycled plastic, allowing for the creation of new products out of recycled plastic on a small |
https://en.wikipedia.org/wiki/Keybase | Keybase is a key directory that maps social media identities to encryption keys (including, but not limited to PGP keys) in a publicly auditable manner. Additionally it offers an end-to-end encrypted chat and cloud storage system, called Keybase Chat and the Keybase Filesystem respectively. Files placed in the public portion of the filesystem are served from a public endpoint, as well as locally from a filesystem mounted by the Keybase client.
Keybase supports publicly connecting Twitter, GitHub, Reddit, and Hacker News identities, including websites and domains under one's control, to encryption keys. It also supports Bitcoin, Zcash, Stellar, and QRL wallet addresses. Keybase has supported Coinbase identities since initial public release, but ceased to do so on March 17, 2017, when Coinbase terminated public payment pages. In general, Keybase allows for any service with public identities to integrate with Keybase.
On May 7, 2020, Keybase announced it had been acquired by Zoom, as part of Zoom's "plan to further strengthen the security of [its] video communications platform".
Identity proofs
Keybase allows users to prove a link between certain online identities (such as a Twitter or Reddit account) and their encryption keys. Instead of using a system such as OAuth, identities are proven by posting a signed statement as the account a user wishes to prove ownership of. This makes identity proofs publicly verifiable – instead of having to trust that the service is being truthful, a user can find and check the relevant proof statements themselves, and the Keybase client does this automatically.
App
In addition to the web interface, Keybase offers a client application for Windows, Mac, Android, iOS, and most desktop Linux distributions, written in Go with an Electron front end. The app offers additional features to the website, such as the end-to-end encrypted chat, teams feature, and the ability to add files to and access private files in their personal and team K |
https://en.wikipedia.org/wiki/Fragmentarium | Fragmentarium (Digital Research Laboratory for Medieval Manuscript Fragments) is an online database to collect and collate fragments of medieval manuscripts making them available to researchers, collectors and historians worldwide. It is an international collaboration of major libraries and collections including the British Library, Bibliothèque nationale de France, Martin Schøyen Collection, Bavarian State Library, Harvard, Yale and the Vatican. It is based in Switzerland and the project's current director is Professor Christoph Flüeler from the University of Fribourg and the Virtual Manuscript Library, Switzerland.
History
The Fragmentarium project was first proposed in October 2013 and the first planning meeting took place in Cologny in 2014. It was supported initially by representatives of 12 institutions, its goal being to study the field of manuscript fragment research and look at worldwide cataloguing standards. Fragmentarium was officially launched on 1 September 2017, by the Medieval Institute of the University of Fribourg at Abbey Library of St. Gall in St. Gallen, Switzerland.
Historians and librarians are now able to upload images to the Fragmentarium where they will be made available for research and encouraged to publish images under a Creative Commons public domain license. The library currently operates as a closed system and will open up public resources gradually from 2018.
Method
Fragmentarium follows an established Swiss codex digitisation system known as e-codices and aims to promote cooperative research and discussion between researchers and scholars from multiple institutions. As more fragments are uploaded it will be possible to reunite fragments which have become separated and compare analyses of similar manuscript pieces. Some fragments have been analysed using the Cornell High Energy Synchrotron Source (CHESS) to identify pigments, creating a unique "fingerprint" to enable it to be matched to corresponding fragments elsewhere in the wor |
https://en.wikipedia.org/wiki/Genetic%20ecology | Genetic ecology is the study of the stability and expression of varying genetic material within abiotic mediums. Typically, genetic data is not thought of outside of any organism save for criminal forensics. However, genetic material has the ability to be taken up by various organisms that exist within an abiotic medium through natural transformations that may occur. Thus, this field of study focuses on interaction, exchange, and expression of genetic material that may not be shared by species had they not been in the same environment.
History
E.B. Ford was the first geneticist to begin work in this field of study. E.B. Ford worked mostly during the 1950s and is most noted for his work with Maniola jurtina and published a book entitled Ecological Genetics in 1975. This type of evolutionary biological study was only possible after gel electrophoresis had been designed in 1937. Prior to this, a high throughput method for DNA analysis did not exist. This field of study began to become more popular following the 1980s with the development of polymerase chain reaction (PCR 1985) and poly-acrylamide gel electrophoresis (p. 1967). With this technology, segments of DNA could be sequenced, amplified, and proteins produced using bacterial transformations. The genetic material along with the proteins could be analyzed and more correct phylogenetic trees could be created.
Since E.B. Ford's research, multiple other genetic ecologists have continued study within the field of genetic ecology such as PT Hanford Alina von Thaden, and many others.
Gene transfer
Genetic information may transfer throughout an ecosystem in multiple ways. The first of which, on the smallest scale, being bacterial gene transfer (see bacterial transformations). Bacteria have the ability to exchange DNA. This DNA exchange, or horizontal gene transfer, may provide various species of bacteria with the genetic information they need to survive in an environment. This can help many bacterial species surviv |
https://en.wikipedia.org/wiki/Housing%20%28engineering%29 | In engineering, a housing or enclosure is a container, a protective exterior (e.g. shell) or an enclosing structural element (e.g. chassis or exoskeleton) designed to enable easier handling, provide attachment points for internal mechanisms (e.g. mounting brackets for electrical components, cables and pipings), maintain cleanliness of the contents by shielding dirt/dust, fouling and other contaminations, or protect interior mechanisms (e.g. delicate integrated electrical fittings) from structural stress and/or potential physical, thermal, chemical, biological or radiational damages from the surrounding environment. Housing may also be the body of a device, vital to its function.
Description
Housing is an exterior case or enclosure used to protect an interior mechanism. The housing prevents the interior mechanism from being fouled by outside debris. It may also have integrated fittings or brackets to keep internal components in place; sometimes a housing is the body of the device, vital to its function.
Design
Housings are most commonly made of metal or plastic. The design of housing is specific to the item and its use. Housing may provide a number of functions.
Contamination control
Housing prevents the interior mechanism from being fouled by outside debris. Housings are sometimes made watertight, especially when the interior mechanisms contain electronics.
Containment
Housings are commonly used to protect gearboxes, where the housing also is responsible for containing the lubricant. Housings can also play a safety role, by providing a barrier between people and dangerous or fast-moving mechanisms.
Interface
Housing may need to provide a user interface for the internal devices, such as for televisions and video game controllers.
Decoration
Housing may include decorative elements. When these elements are removable and replaceable panels, they may be known as faceplates. Interchangeable faceplates provide a method to update the cosmetics of the housing without |
https://en.wikipedia.org/wiki/Atmospheric%20Chemistry%20Suite | The Atmospheric Chemistry Suite (ACS) is a science payload consisting of three infrared spectrometer channels aboard the ExoMars Trace Gas Orbiter (TGO) orbiting Mars since October 2016. The three channels are: the near-infrared channel (NIR), the mid-infrared channel (MIR), and the far infrared channel (FIR, also called TIRVIM).
The ACS was proposed in 2011 by Russian Academy Section and eventually accepted by the European Space Agency (ESA) and Roscosmos as one of two Russian instruments onboard TGO. The instrument was funded by Roscosmos and Centre national d'études spatiales (CNES) of France, and has components of both Russia and France. Its development and fabrication was under Russian leadership. The functionality of all the three channels was confirmed during cruise to Mars.
Objectives
The main objective of the ACS suite is to make an inventory and map minor atmospheric species or trace gases in the atmosphere of Mars. This will allow scientists to profile the upper limits on the methane contents, and to possibly to detect sulfur dioxide (), a gas of volcanic origin.
Channels
The near-infrared channel (NIR), is a compact spectrometer operating in the range of 0.7–1.7 μm
with a resolving power of λ/Δλ ~ 20,000 and with a spectral range of 10–20 nm. It is designed to operate in nadir and in solar occultation modes.
The mid-infrared channel (MIR) is an echelle spectrometer with crossed dispersion, designed exclusively
for solar occultation measurements in the 2.2–4.4 μm spectral range with a resolving power of approximately 50,000.
The far-infrared channel covers the thermal infrared spectroscopy; it is a Fourier spectrometer called the TIRVIM. It has an aperture of ~5 cm and it measures the spectrum of 1.7–17 μm. Its main task will be for temperature sounding of the Martian atmosphere in the 15-μm band. TIRVIM has 10 times higher
performances than the PFS spectrometer of Mars Express orbiter.
Methane
Of particular interest to this astrobiology mis |
https://en.wikipedia.org/wiki/Infinite-order%20hexagonal%20tiling | In 2-dimensional hyperbolic geometry, the infinite-order hexagonal tiling is a regular tiling. It has Schläfli symbol of {6,∞}. All vertices are ideal, located at "infinity", seen on the boundary of the Poincaré hyperbolic disk projection.
Symmetry
There is a half symmetry form, , seen with alternating colors:
Related polyhedra and tiling
This tiling is topologically related as a part of sequence of regular polyhedra and tilings with vertex figure (6n).
See also
Hexagonal tiling
Uniform tilings in hyperbolic plane
List of regular polytopes
References
External links
Hyperbolic and Spherical Tiling Gallery
Hyperbolic tilings
Infinite-order tilings
Isogonal tilings
Isohedral tilings
Hexagonal tilings
Regular tilings |
https://en.wikipedia.org/wiki/Order-6%20apeirogonal%20tiling | In geometry, the order-6 apeirogonal tiling is a regular tiling of the hyperbolic plane. It has Schläfli symbol of {∞,6}.
Symmetry
The dual to this tiling represents the fundamental domains of [∞,6*] symmetry, orbifold notation *∞∞∞∞∞∞ symmetry, a hexagonal domain with five ideal vertices.
The order-6 apeirogonal tiling can be uniformly colored with 6 colored apeirogons around each vertex, and coxeter diagram: , except ultraparallel branches on the diagonals.
Related polyhedra and tiling
This tiling is also topologically related as a part of sequence of regular polyhedra and tilings with six faces per vertex, starting with the triangular tiling, with Schläfli symbol {n,6}, and Coxeter diagram , with n progressing to infinity.
See also
Tilings of regular polygons
List of uniform planar tilings
List of regular polytopes
References
John H. Conway, Heidi Burgiel, Chaim Goodman-Strauss, The Symmetries of Things 2008, (Chapter 19, The Hyperbolic Archimedean Tessellations)
External links
Hyperbolic and Spherical Tiling Gallery
KaleidoTile 3: Educational software to create spherical, planar and hyperbolic tilings
Hyperbolic Planar Tessellations, Don Hatch
Apeirogonal tilings
Hyperbolic tilings
Isogonal tilings
Isohedral tilings
Order-6 tilings
Regular tilings |
https://en.wikipedia.org/wiki/List%20of%20oldest%20fathers | This is a list of persons reported to have become father of a child at or after 75 years of age. These claims have not necessarily been verified.
Medical considerations
According to a 1969 study, there is a decrease in sperm concentration as men age. The study reported that 90% of seminiferous tubules in men in their 20s and 30s contained spermatids, whereas men in their 40s and 50s had spermatids in 50% of their seminiferous tubules. In the study, only 10% of seminiferous tubules from men aged > 80 years contained spermatids. In a random international sample of 11,548 men confirmed to be biological fathers by DNA paternity testing, the oldest father was found to be 66 years old at the birth of his child; the ratio of DNA-confirmed versus DNA-rejected paternity tests around that age is in agreement with the notion of general male infertility greater than age 65-66.
List of claims
See also
List of oldest birth mothers
List of people with the most children
List of multiple births
Pregnancy
Abraham and his son Isaac
Genealogies of Genesis including multiple accounts of super-aged fathers
References
External links
Well Known Fathers After 50
Who's broody now?
Older men who want to go from here to paternity
Fathers
Gerontology
Sexuality and age
Lists of men
Fatherhood
Human pregnancy
Biological records
Oldest things
Parenting-related lists |
https://en.wikipedia.org/wiki/Proper%20generalized%20decomposition | The proper generalized decomposition (PGD) is an iterative numerical method for solving boundary value problems (BVPs), that is, partial differential equations constrained by a set of boundary conditions, such as the Poisson's equation or the Laplace's equation.
The PGD algorithm computes an approximation of the solution of the BVP by successive enrichment. This means that, in each iteration, a new component (or mode) is computed and added to the approximation. In principle, the more modes obtained, the closer the approximation is to its theoretical solution. Unlike POD principal components, PGD modes are not necessarily orthogonal to each other.
By selecting only the most relevant PGD modes, a reduced order model of the solution is obtained. Because of this, PGD is considered a dimensionality reduction algorithm.
Description
The proper generalized decomposition is a method characterized by
a variational formulation of the problem,
a discretization of the domain in the style of the finite element method,
the assumption that the solution can be approximated as a separate representation and
a numerical greedy algorithm to find the solution.
Variational formulation
The most implemented variational formulation in PGD is the Bubnov-Galerkin method, although other implementations exist.
Domain discretization
The discretization of the domain is a well defined set of procedures that cover (a) the creation of finite element meshes, (b) the definition of basis function on reference elements (also called shape functions) and (c) the mapping of reference elements onto the elements of the mesh.
Separate representation
PGD assumes that the solution u of a (multidimensional) problem can be approximated as a separate representation of the form
where the number of addends N and the functional products X1(x1), X2(x2), ..., Xd(xd), each depending on a variable (or variables), are unknown beforehand.
Greedy algorithm
The solution is sought by applying a greedy alg |
https://en.wikipedia.org/wiki/Tamarin%20Prover | Tamarin Prover is a computer software program for formal verification of cryptographic protocols. It has been used to verify Transport Layer Security 1.3, ISO/IEC 9798, and DNP3 Secure Authentication v5.
References
External links
Tamarin Prover official website
David Wong created an introductory video on the Tamarin Prover.
Cryptographic software
Free software |
https://en.wikipedia.org/wiki/Quantum%20image | Quantum computation, which exploits quantum parallelism, is in principle faster than a classical computer for certain problems.
Quantum image is encoding the image information in quantum-mechanical systems instead of classical ones and replacing classical with quantum information processing may alleviate some of these challenges.
Humans obtain most of their information through their eyes. Accordingly, the analysis of visual data is one of the most important functions of our brain and it has evolved high efficiency in processing visual data. Currently, visual information like images and videos constitutes the largest part of data traffic in the internet. Processing of this information requires ever-larger computational power.
The laws of quantum mechanics allow one to reduce the required resources for some tasks by many orders of magnitude if the image data are encoded in the quantum state of a suitable physical system. The researchers discuss a suitable method for encoding image data, and develop a new quantum algorithm that can detect boundaries among parts of an image with a single logical operation. This edge-detection operation is independent of the size of the image. Several other algorithms are also discussed. It is theoretically and experimentally demonstrated that they work in practice. This is the first experiment to demonstrate practical quantum image processing. It contributes a substantial progress towards both theoretical and experimental quantum computing for image processing, it will stimulate future studies in the field of quantum information processing of visual data.
See also
Quantum computing
Quantum image processing
References
Quantum computing |
https://en.wikipedia.org/wiki/OpenHPC | OpenHPC is a set of community-driven FOSS tools for Linux based HPC. OpenHPC does not have specific hardware requirements.
History
A birds-of-a-feather panel discussion titled "Community Supported HPC Repository & Management Framework" convened at the 2015 edition of the International Supercomputing Conference. The panel discussed the common software components necessary to build linux compute clusters and solicited feedback on community interest in such a project. Following the response, the OpenHPC project was announced at SC 2015 under the auspices of the Linux Foundation.
Releases
Design
OpenHPC provides an integrated and tested collection of software components that, along with a supported standard Linux distribution, can be used to implement a full-featured compute cluster. Components span the entire HPC software ecosystem including provisioning and system administration tools, resource management, I/O services, development tools, numerical libraries, and performance analysis tools. The architecture of OpenHPC is intentionally modular to allow end users to pick and choose from the provided components, as well as to foster a community of open contribution. The project provides recipes for building clusters using CentOS (v8.3) and openSUSE Leap (v15.2) on x86_64 as well as aarch64 architectures.
See also
Cluster manager
Comparison of cluster software
List of cluster management software
References
External links
OpenHPC: A Comprehensive System Software Stack
Next Platform – OpenHPC Pedal Put To The Compute Metal
HPCwire – OpenHPC Pushes to Prove its Openness and Value at SC16
High Performance Computing: 32nd International Conference
OpenHPC Slack channel
Cluster computing
High-availability cluster computing
Job scheduling
Parallel computing |
https://en.wikipedia.org/wiki/Digital%20Rights%20Watch | Digital Rights Watch is an Australian charity organisation founded in 2016 that aims to educate and uphold the digital rights of Australian citizens.
History
In 2016, largely in response to the introduction of Australia's mandatory metadata retention scheme, Digital Rights Watch was created at a meeting of representatives from Australian human rights organisations, activists, political advisers, technology consultants and academics. To coordinate a civil society response to the metadata retention scheme as well as other key digital rights violations, a new organisation was founded with the aim of aligning and supporting existing efforts.
Focus
Digital Rights Watch's mission is to ensure that Australian citizens are equipped, empowered and enabled to uphold their digital rights. The organisation works on advocacy, policy reform and public-facing campaigns that push for ethical data use by corporations, good digital government practices and policies, a rights-based legal system, and empowered and informed citizens.
Structure
Digital Rights Watch is an incorporated Association, registered as a national charity with the Australian Charities and Not-For-Profits Commission. It is a member-run organisation, with a board of directors elected once a year at its Annual General Meeting. The organisation also operates an Advisory Council, which informs and advises on policy and strategy.
Digital Rights Watch is a member of the CIVICUS World Alliance for Citizen Participation, the Australian Digital Inclusion Alliance, and the global Keep It On campaign. In October 2017, Digital Rights Watch's Chair Tim Singleton Norton received a special mention in the Access Now Global Heroes and Villains of Human Rights Awards.
Digital Rights Watch often works in partnerships with other Australian digital or human rights organisations such as the Human Rights Law Centre, Amnesty International Australia, Electronic Frontiers Australia, the Australian Privacy Foundation, ACFID and othe |
https://en.wikipedia.org/wiki/SAP%20Converged%20Cloud | SAP Converged Cloud is a private managed cloud developed and marketed by SAP.
It is a set of cloud computing services that offer managed private cloud, based on the OpenStack technology-based public cloud. It is used by SAP's organization for their own internal IT resources to create a mix of different cloud computing environments made up of the OpenStack services.
It offers compute, storage, and platform services that are accessible to SAP.
History
In 2012, SAP promoted aspects of cloud computing. In October 2012, SAP announced a platform as a service called the SAP Cloud Platform.
In May 2013, a managed private cloud called the S/4HANA Enterprise Cloud service was announced.
SAP Converged Cloud was announced in January 2015. SAP Converged Cloud is managed under The Converged Cloud unit, an SAP business unit established in 2015 headed by Markus Riedinger as Unit manager.
The Converged Cloud BETA went live in May 2017, included OpenStack technology-based storage, compute network components, and shared new services made by SAP: Later, Designate (DNS as a Service) was added as well.
In 2020, SAP donated spare GPUs and CPUs from its cloud data center to Folding@Home to aid in their COVID-19 research efforts.
Cloud computing challenges
Moving between clouds
Business organizations that want to use cloud computing have a choice of using a private cloud, which is a cloud infrastructure run specifically for a single organization that it built itself or by a third party, or a public cloud, whereby a service provider makes available applications, storage, and other resources to the general public. The decision of which to use is based on a number of factors, such as whether the company operates in a highly regulated sector, such as the pharmaceuticals industry that must comply with rules regarding the control and security of data, or if the business must bring services to market quickly, such as a web applications developer.
Employing a hybrid delivery cloud strate |
https://en.wikipedia.org/wiki/Ovarian%20follicle%20activation | Ovarian follicle activation can be defined as primordial follicles in the ovary moving from a quiescent (inactive) to a growing phase. The primordial follicle in the ovary is what makes up the “pool” of follicles that will be induced to enter growth and developmental changes that change them into pre-ovulatory follicles, ready to be released during ovulation. The process of development from a primordial follicle to a pre-ovulatory follicle is called folliculogenesis.
Activation of the primordial follicle involves the following: a morphological change from flattened to cuboidal granulosa cells, proliferation of granulosa cells, formation of the protective zona pellucida layer, and growth of the oocyte.
It is widely understood that androgens act primarily on preantral follicles and that this activity is important for preantral follicle growth. Additionally, it is thought that androgens are involved in primordial follicle activation. However, the influence of androgens on primordial follicle recruitment and whether this response is primary or secondary is still uncertain.
Activation of Primordial Follicle Development
Primordial follicles are activated to grow into antral follicles. Communication between the oocytes and the surrounding somatic cells, such as the granulosa cells and the theca cells, is involved in the control of primordial follicle activation. There are various activator signalling pathways that are involved in the control of ovarian follicle activation, including: Neurotropin, nerve growth factor (NGF) and its tyrosine receptor kinase (NTRK1), neurotrophin 4 (NT4), brain-derived neurotrophic factor (BDNF) and their receptor NTRK2. Additional ligands have a role in facilitating primordial follicle activation such as transforming growth factor-beta (TGF-B), growth differentiation factor 9 (GDF9) and bone morphogenic protein 15 (BMP15).
GDF9
Follicular activation rate is increased in experiments where recombinant GDF9 is added. Additionally, in vitro |
https://en.wikipedia.org/wiki/History%20of%20magnetic%20resonance%20imaging | The history of magnetic resonance imaging (MRI) includes the work of many researchers who contributed to the discovery of nuclear magnetic resonance (NMR) and described the underlying physics of magnetic resonance imaging, starting early in the twentieth century. MR imaging was invented by Paul C. Lauterbur who developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients in September 1971; he published the theory behind it in March 1973. The factors leading to image contrast (differences in tissue relaxation time values) had been described nearly 20 years earlier by physician and scientist Erik Odeblad and Gunnar Lindström. Among many other researchers in the late 1970s and 1980s, Peter Mansfield further refined the techniques used in MR image acquisition and processing, and in 2003 he and Lauterbur were awarded the Nobel Prize in Physiology or Medicine for their contributions to the development of MRI. The first clinical MRI scanners were installed in the early 1980s and significant development of the technology followed in the decades since, leading to its widespread use in medicine today.
Nuclear magnetic resonance
In 1950, spin echoes and free induction decay were first detected by Erwin Hahn and in 1952, Herman Carr produced a one-dimensional NMR spectrum as reported in his Harvard PhD thesis.
The next step (from spectra to imaging) was proposed by Vladislav Ivanov in Soviet Union, who filed in 1960 a patent application for a Magnetic Resonance Imaging device. Ivanov's main contribution was the idea of using magnetic field gradient, combined with a selective frequency excitation/readout, to encode the spatial coordinates. In modern terms, it was only proton-density (not relaxation times) imaging, which was also slow, since only one gradient direction was used at a time and the imaging had to be done slice-by-slice. Nevertheless, it was a true magnetic resonance imaging procedure. Originally rejected as "improbable", I |
https://en.wikipedia.org/wiki/Tianchi%20basin | Tianchi basins were meteorological measuring instruments used to gather and measure the amount of liquid precipitation over a period of time during the Song Dynasty. The instrument was devised by the Song Chinese mathematician and inventor Qin Jiushao in 1247.
History and usage
As precipitation was for important agriculture and food production, the Song Chinese mathematician and inventor Qin Jiushao developed a precipitation gauge that was widely used in 1247 during the Southern Song dynasty to gather meteorological data. Qin Jiushao later records application of rainfall measurements in the mathematical treatise Mathematical Treatise in Nine Sections. The book also discusses problems using large snow gauges made from bamboo situated in mountain passes and uplands which are speculated to be first referenced to snow measurement.
Tianchi basins were installed at provincial and district capitals and bamboo snow gauges were situated in mountain passes. The rain gauges were bowl-shaped with one being installed at each provincial and district capital in China. In the treatise, Qin Jiushao also discusses how point measurements were converted to real averages. These averages were important as they postulated indicators of natural disasters such as flooding, since river flooding has always been a problem in China.
Notes
Chinese inventions
Measuring instruments
Meteorological instrumentation and equipment
Rain
Song dynasty |
https://en.wikipedia.org/wiki/IObit%20Malware%20Fighter | IObit Malware Fighter (introduced in 2004) is an anti-malware and anti-virus program for the Microsoft Windows operating system (Windows XP and later). It is designed to remove and protect against malware, including, but not limited to Trojans, rootkits, and ransomware.
Overview
IObit Malware Fighter has a freeware version, which can run alongside the user's existing anti-virus solution. In the paid edition, the product comes with anti-virus protection. As of version 6, released in 2018, the product includes the Bitdefender engine in its commercial version, along with its anti-malware engine. New features of the latest release includes an improved user interface called "Safe Box" created to protect specific folders from unauthorized access, and "MBR Guard" which protects the user's system from malicious attacks such as Petya and cryptocurrency mining scripts.
Releases
In 2010, the first beta for IObit Malware Fighter 1.0 was released to the public.
In 2013, IObit Malware Fighter 2 was released. In this version, IObit debuted its "cloud security" component, in which the user can upload a file to the cloud to determine whether it is malicious or not. In 2015, version 3 was released, and then, in 2016, version 4, which added the Bitdefender anti-virus engine in its commercial edition.
In 2017, version 5 was released. Among new features was an anti-ransomware component. Version 6 was released in May 2018.
In 2018, version 6 was released. It added new features, including Safe Box, and MBR Guard.
Reception
In November 2011, the free and paid versions of IObit Malware Fighter were reviewed by Bright Hub, in which the reviewer was unable to recommend the product, citing poor malware protection.
In May 2013, IObit Malware Fighter received a "dismal" score, half a star out of five, for its paid version by PC Magazine.
In December 2013, the paid version of IObit Malware Fighter received a 1 out of 5-star rating from Softpedia.
In March 2015, the commercial version of I |
https://en.wikipedia.org/wiki/Highway%20network | In machine learning, the Highway Network was the first working very deep feedforward neural network with hundreds of layers, much deeper than previous artificial neural networks.
It uses skip connections modulated by learned gating mechanisms to regulate information flow, inspired by Long Short-Term Memory (LSTM) recurrent neural networks.
The advantage of a Highway Network over the common deep neural networks is that it solves or partially prevents the vanishing gradient problem, thus leading to easier to optimize neural networks.
The gating mechanisms facilitate information flow across many layers ("information highways").
Highway Networks have been used as part of text sequence labeling and speech recognition tasks.
An open-gated or gateless Highway Network variant called Residual neural network was used to win the ImageNet 2015 competition. This has become the most cited neural network of the 21st century.
Model
The model has two gates in addition to the H(WH, x) gate: the transform gate T(WT, x) and the carry gate C(WC, x). Those two last gates are non-linear transfer functions (by convention Sigmoid function). The H(WH, x) function can be any desired transfer function.
The carry gate is defined as C(WC, x) = 1 - T(WT, x). While the transform gate is just a gate with a sigmoid transfer function.
Structure
The structure of a hidden layer follows the equation:
References
Machine learning |
https://en.wikipedia.org/wiki/Criticism%20of%20Spotify | Spotify, a music streaming company, has attracted significant criticism since its 2006 launch, mainly over artist compensation. Unlike physical sales or downloads, which pay artists a fixed price per song or album sold, Spotify pays royalties based on the artist's "market share"—the number of streams for their songs as a proportion of total songs streamed on the service. Spotify distributes approximately 70% of its total revenue to rights holders, who then pay artists based on their individual agreements. Multiple artists have criticised the policy, most notably Thom Yorke and Taylor Swift, who temporarily withdrew their music from the service.
Spotify faces particular scrutiny due to its free service tier, which allows users to listen free with advertisements between tracks. The tier has led to a variety of major album releases being delayed or withdrawn from the service. Spotify claims it benefits the industry by migrating users away from piracy and less monetized platforms and encouraging them to upgrade to paid accounts. Record labels keep a large amount of Spotify earnings.
Spotify has also attracted media attention for several security breaches, as well as for controversial moves including a significant change to its privacy policy, "pay-for-play" practices based on receiving money from labels for putting specific songs on popular playlists, and allegedly creating "fake artists" for prominent playlist placement, which Spotify denies.
Spotify CEO Daniel Ek was also criticized for making donations through his investment company to military research of artificial intelligence.
Business practices
Allegations of unfair artist compensation
Spotify, together with the music streaming industry in general, faces criticism from some artists and producers, claiming they are being unfairly compensated for their work as music sales decline and music streaming increases. Unlike physical sales or legal downloads, which pay artists a fixed price per song or album sold, S |
https://en.wikipedia.org/wiki/Meat%20Research%20Institute | The Meat Research Institute was a research institute in North Somerset. It was founded in 1967 to provide research for the British meat industry.
History
In the late 1950s there was a need in the UK for a meat research institute, but no further plans. In March 1962 there was a meeting with thirty one meat producers and representatives from the government and it was decided to build a meat research institute, costing around £500,000 and annual running costs of around £100,000. The first director was appointed in February 1963, before the building construction had begun, who came from the Low Temperature Research Station in Cambridge. It was decided to put the research institute next to the veterinary school. Planning permission for the site was issued in May 1963.
To pay for the cost of the institute, the government put a levy on livestock, later administered by the Meat and Livestock Commission. In October 1966, a new £1m Food Research Institute was announced to be built at Norwich, similarly next to the university. The institute in Somerset was hoped to open in the autumn of 1967. In November 1967 staff moved in.
The Queen, with the Duke of Northumberland and Henry Somerset, 10th Duke of Beaufort, officially opened the new institute on 19 April 1968, also opening new buildings of the veterinary school next door. Buglers played The Roast Beef of Old England.
It became part of the IFR in Norfolk in 1985, when merged with the National Institute for Research in Dairying, which is now the Quadram Institute Bioscience. In 1990 the government decided to stop funding to the research institute, and the research institute closed in December 1990.
Structure
It was at Lower Langford in North Somerset. It was situated next to the Langford House School of Veterinary Science, on the B3133 (for Congresbury), north of the A38.
See also
British Meat Processors Association
References
External links
Research site
1967 establishments in the United Kingdom
1990 disestablishme |
https://en.wikipedia.org/wiki/Ocean%20Worlds%20Exploration%20Program | The Ocean Worlds Exploration Program (OWEP) is a NASA program to explore ocean worlds in the outer Solar System that could possess subsurface oceans to assess their habitability and to seek biosignatures of simple extraterrestrial life.
Prime targets include moons that harbor hidden oceans beneath a shell of ice: Europa, Enceladus, and Titan. A host of other bodies in the outer Solar System are inferred by a single type of observation or by theoretical modeling to have subsurface oceans.
The US House Appropriations Committee approved the bill on May 20, 2015, and directed NASA to create the Ocean Worlds Exploration Program. The "Roadmaps to Ocean Worlds" (ROW) was started in 2016, and was presented in January 2019. The formal program is being implemented within the agency by supporting the Europa Clipper orbiter mission to Europa, and the Dragonfly mission to Titan. The program is also supporting concept studies for a proposed Europa Lander, and concepts to explore the moon Triton. Amanda Hendrix and Terry A. Hurford are the co-leads of the NASA Roadmaps to Oceans World Group.
History
The chief author of NASA's budget proposal is John Culberson, who was at the time the head of the science subcommittee in the House of Representatives. In Spring 2015 he presented a budget request, creating the possibility of an all-new NASA mission program. The House Appropriations Committee approved its version of the FY2016 House Appropriations Commerce-Justice-Science (CJS) bill on May 20, 2015. Therefore, the Committee directed NASA to create the Ocean Worlds Exploration Program whose primary goal is to discover extant life on another world using a mix of Discovery, New Frontiers and Flagship class missions consistent with the recommendations of current and future Planetary Science Decadal Surveys.
In the FY2017 Budget Request, the committee recommended $348 million for "Outer Planets" and "Ocean Worlds," of which not less than $260 million is for the Europa Clipper orbiter a |
https://en.wikipedia.org/wiki/Roger%20Kemp%20%28engineer%29 | Roger John Kemp is a professorial fellow in engineering at Lancaster University. He was engineering manager for the Docklands Light Railway in London and managed the design and development team at Eurostar.
References
External links
Lancaster University – Roger Kemp
Lancaster University researchdirectory – Professor Roger Kemp MBE BSc FREng CEng FIET
Living people
Academics of Lancaster University
Members of the Order of the British Empire
Alumni of the University of Sussex
English railway mechanical engineers
Fellows of the Royal Academy of Engineering
Year of birth missing (living people) |
https://en.wikipedia.org/wiki/Gas%20immersion%20laser%20doping | Gas immersion laser doping (GILD) is a method of doping a semiconductor material such as silicon.
In the case of doping silicon with boron to create a P-type semiconductor material, a thin wafer of silicon is placed in a containment chamber and is immersed in boron gas. A pulsed laser is directed at the silicon wafer and this results in localised melting and subsequent recrystallisation of the silicon wafer material, allowing boron atoms in the gas to diffuse into the molten sections of the silicon wafer. The result of this process is a silicon wafer with boron impurities, creating a P-type semiconductor.
References
Further reading
Semiconductor device fabrication |
https://en.wikipedia.org/wiki/M%C3%B8lmer%E2%80%93S%C3%B8rensen%20gate | In quantum computing, Mølmer–Sørensen gate scheme (or MS gate) refers to an implementation procedure for various multi-qubit quantum logic gates used mostly in trapped ion quantum computing. This procedure is based on the original proposition by Klaus Mølmer and Anders Sørensen in 1999-2000.
This proposal was an alternative to the 1995 Cirac–Zoller controlled-NOT gate implementation for trapped ions, which requires that the system be restricted to the joint motional ground state of the ions.
In an MS gate, entangled states are prepared by illuminating ions with a bichromatic light field. Mølmer and Sørensen identified two regimes in which this is possible:
A weak-field regime, where single-photon absorption is suppressed and two-photon processes interfere in a way that makes internal state dynamics insensitive to the vibrational state
A strong-field regime where the individual ions are coherently excited, and the motional state is highly entangled with the internal state until all undesirable excitations are deterministically removed toward the end of the interaction.
In both regimes, a red and blue sideband interaction are applied simultaneously to each ion, with the red and blue tones symmetrically detuned by from the sidebands. This results in laser detunings , where is the motional mode frequency.
When an MS gate is applied globally to all ions in a chain, multipartite entanglement is created, with the form of the gate being a sum of local XX (or YY, or XY depending on experimental parameters) interactions applied to all qubit pairs. When the gate is performed on a single pair of ions, it reduces to the RXX gate. Thus, the CNOT gate can be decomposed into an MS gate and combination of single particle rotations.
History
Trapped ions were identified by Ignacio Cirac and Peter Zoller at the University of Innsbruck, Austria in 1995, as the first realistic system with which to implement a quantum computer, in a proposal which included a procedure for imp |
https://en.wikipedia.org/wiki/Vaginamuseum | The virtual Vaginamuseum is an international internet project, founded by the Austrian artist, Kerstin Rajnar, in 2014. It consists in a virtual gallery and a virtual archive containing background information about the female sex and femininity. Various representations of female sexual organs indicate the existence of a female role model in social systems and allow conclusions to be drawn as to the importance of women in different environments. This project aims at promoting the artistic creation and debate about the female sex. It supports the positive meanings and appreciation of the words and body parts such as the vagina, vulva, and clitoris. The museum is considered the first to be devoted to the vagina.
About
The Vaginamuseum communicates informations and is an educational platform. Experts of art history, health care, medical science, as well as artists of all disciplines, are creating this platform. The archive displays conceptual and historical texts and other articles and contributions about the vagina, the vulva and the clitoris. The curated gallery shows selected artworks which stimulate new thinking about the female genital and lead to new perspectives. Rajnar's vision is that the museum can help improve people's negative attitudes about the vagina which are shaped through culture and media.
The Vaginamuseum elaborated concepts on the topic: Art and Culture and Life and Limb _ the positive Power of Feminity.
Vaginamuseum is registered at the European Union Intellectual Property Office (EUIPO).
Exhibitions in the gallery
Vagina 2.0
The virtual opening exhibition curated by the media artist and curator Doris Jauk-Hinz broaches the issue of current terms and subjective meanings of the female sexual organs. Reflections in dealing with the term vagina are based on ideas, expectations, attributions, associations and emotions by means of art. The artistic inputs range from earlier depictions of vulva symbols in different civilizations and times to the l |
https://en.wikipedia.org/wiki/CRISPR%20activation | CRISPR activation (CRISPRa) is a type of CRISPR tool that uses modified versions of CRISPR effectors without endonuclease activity, with added transcriptional activators on dCas9 or the guide RNAs (gRNAs).
Like for CRISPR interference, the CRISPR effector is guided to the target by a complementary guide RNA. However, CRISPR activation systems are fused to transcriptional activators to increase expression of genes of interest. Such systems are usable for many purposes including but not limited to, genetic screens and overexpression of proteins of interest.
The most commonly-used effector is based on Cas9 (from Type II systems), but other effectors like Cas12a (Type V) have been used as well.
Components
dCas9
Cas9 Endonuclease Dead, also known as dead Cas9 or dCas9, is a mutant form of Cas9 whose endonuclease activity is removed through point mutations in its endonuclease domains. Similar to its unmutated form, dCas9 is used in CRISPR systems along with gRNAs to target specific genes or nucleotides complementary to the gRNA with PAM sequences that allow Cas9 to bind. Cas9 ordinarily has 2 endonuclease domains called the RuvC and HNH domains. The point mutations D10A and H840A change 2 important residues for endonuclease activity that ultimately results in its deactivation. Although dCas9 lacks endonuclease activity, it is still capable of binding to its guide RNA and the DNA strand that is being targeted because such binding is managed by other domains. This alone is often enough to attenuate if not outright block transcription of the targeted gene if the gRNA positions dCas9 in a way that prevents transcriptional factors and RNA polymerase from accessing the DNA. However, this ability to bind DNA can also be exploited for activation since dCas9 has modifiable regions, typically the N and C terminus of the protein, that can be used to attach transcriptional activators.
Guide RNA
See: Guide RNA, CRISPR
A small guide RNA (sgRNA), or gRNA is an RNA with around |
https://en.wikipedia.org/wiki/Payconiq | Payconiq International S.A. is a Luxembourg-based company developing a mobile payment and payment processing platform, active in Luxembourg and Belgium. The company had the initial support of ING Bank, which was joined later by Belgian banks KBC Bank and Belfius, and launched its first minimum-viable product in Belgium, in 2015. The company discontinued its services in the Netherlands on 1 January 2022. The less complete mobile app is today a more fleshed-out platform offering multi-country payment solutions in Benelux, through different types of integration: stand-alone apps, bank app integrations and more.
Luxembourg
Payconiq International established its headquarters in Luxembourg through the acquisition of the Luxembourgish fintech startup Digicash Payments, in 2017.
In 2019, the company received its Payment Initiation Service license from the Luxembourgish regulator CSSF and some extra financing from its shareholders, amounting to EUR 20 million.
In 2020, the five Digicash apps were rebranded to Digicash by Payconiq, as the company made all its mobile solutions in the Benelux area interoperable. In 2021, the Digicash merchants have started migrating to the Payconiq platform.
Belgium
Payconiq Belgium and the Belgian payment system announced in March 2018 their intention to merge. The merger was finalized in July 2018 and the company is currently named Bancontact Payconiq Company. The new company got a capital injection of €17,6 million from its five major shareholders Belfius, BNP Paribas Fortis, ING, KBC and AXA. It then also merged its two existing payment apps called 'Payconiq' and 'Bancontact' into one app called 'Payconiq by Bancontact' which was supported by 20 Belgian banks and 290.000 stores in Belgium.
In 2019, the Payconiq payment solution was integrated in KBC's mobile bank app, followed by ING Belgium, in 2020.
The Netherlands
Payconiq Netherlands was established in 2018, when the Payconiq mobile payment app was launched into the market, |
https://en.wikipedia.org/wiki/ArchLabs | ArchLabs Linux is a lightweight rolling release Linux distribution based on a minimal Arch Linux operating system with the Openbox window manager. ArchLabs is inspired by BunsenLabs.
Features
The ArchLabs distribution contains a text-based installer, "AL-Installer" as its installation method, as well as baph, an AUR helper. The installer gives the user the ability to choose from 16 different assorted Desktop Environments and Window Managers as well as a selection of extra software, Linux Kernels, Display Managers and shells.
History
Initial releases used the Calamares installer. Early versions of ArchLabs started to become bloated with many unnecessary applications and programs. This sparked a change in direction. A slim down of the ISO size from over 2Gb in size down to approximately 580mb made download times a lot quicker.
Mínimo was the first of this minimal release with a change from the traditional Openbox panel, Tint2 to Polybar. Also introduced in this release was the original welcome script, named "AL-Hello" which was a nod to the "brother" distribution BunsenLabs. Mínimo was also the final release to have a release name, following releases followed a numbering pattern of YYYY.MM.
2018.02 release brought a new and improved AL-Hello welcome script and many additions and refining to the ArchLabs experience.
2018.07 saw more improvements to the newly written AL-Installer.
With the release of 2018.12 came the removal of the live environment and the post install script "AL-Hello". Options for choosing desktops and window managers as well as a selection of apps have been added to AL-Installer (ALI). Also introduced in this 2018.12 release was the in house AUR (Arch User Repository) Helper, baph (Basic AUR Package Helper).
2019.10.29 was ArchLabs third release for 2019 (After 2019.1.20 & 2019.10.28). Many changes were made including additional desktop environments and window managers added to the installer. Most notably, awesomewm and jwm.
ArchLabs firs |
https://en.wikipedia.org/wiki/Japanese%20army%20and%20diplomatic%20codes | Japanese army and diplomatic codes. This article is on Japanese army and diplomatic ciphers and codes used up to and during World War II, to supplement the article on Japanese naval codes. The diplomatic codes were significant militarily, particularly those from diplomats in Germany.
Japanese army (IJA) and diplomatic codes were studied at Arlington Hall (US), Bletchley Park (UK), Central Bureau or CBB (Australian, US; in Melbourne, then Brisbane), the FECB (British Far East Combined Bureau) at Hong Kong, Singapore, Kilindi then Colombo and the British Wireless Experimental Centre in Delhi.
Japanese Army codes and ciphers
Arlington Hall had initially delayed study of the Army codes until 1942 because of the "high payoff" from diplomatic codes, but were not successful until 1943. Then, with success on Army codes in April, the increasing workload was put under Solomon Kullback in branch B-II in September. Other mainly diplomatic work was put under Frank Rowlett in B-III. Branch B-I translated Japanese.
Initially, "brute-force" IBM runs on Army codes from April 1942 to the end of the year did not work. but U.S. Army Sgt. Joe Richard noticed that the system for 2468 changed every three weeks, so the messages could be arranged by IBM tabulators by group and time period. Richard was assisted at Central Bureau by Major Harry Clark and by the head, Abraham "Abe" Sinkov, and broke 2468 on 6 April 1943, for which he was awarded the Legion of Merit. Wilfrid Noyce at the Wireless Experimental Centre had realised that the first letter of the third group of each message was not random and that other groups were paired in "doublets".
At first, Arlington Hall could not find the non-randomness until Richard told them it changed about every four weeks. With this tip Arlington Hall broke the code, as did the Wireless Experimental Centre. It used a 10×10 conversion square with the plaintext digits 0-9 across the top, key digits down the side, and the table contained the cipher t |
https://en.wikipedia.org/wiki/Comparison%20of%20API%20simulation%20tools | The tools listed here support emulating or simulating APIs and software systems. They are also called API mocking tools, service virtualization tools, over the wire test doubles and tools for stubbing and mocking HTTP(S) and other protocols. They enable component testing in isolation.
In alphabetical order by name (click on a column heading to sort by that column):
See also
Test double
Service virtualization
References
Computing comparisons |
https://en.wikipedia.org/wiki/Gemini%20Wing | Gemini Wing is a vertically scrolling shooter created by Tecmo and released in arcades in 1987. One or two players control a futuristic aircraft flying over terrain and shooting enemies of an animalistic or insectoid design.
Home conversions were released for the ZX Spectrum, Commodore 64, Amstrad CPC, Amiga, Atari ST, MSX, and X68000.
Reception
In Japan, Game Machine listed Gemini Wing on their December 15, 1987 issue as being the eighth most-successful table arcade unit of the month.
References
External links
Gemini Wing at Lemon Amiga
Gemini Wing at Atari Mania
Tecmo games
1987 video games
Arcade video games
Vertically scrolling shooters
Amiga games
Amstrad CPC games
Atari ST games
Commodore 64 games
ZX Spectrum games
MSX games
Nintendo Switch games
PlayStation 4 games
SCi Games games
X68000 games
Video games developed in Japan
Video games scored by Barry Leitch
Hamster Corporation games
Multiplayer and single-player video games |
https://en.wikipedia.org/wiki/Geometry%20and%20the%20Imagination | Geometry and the Imagination is the English translation of the 1932 book by David Hilbert and Stefan Cohn-Vossen.
The book was based on a series of lectures Hilbert made in the winter of 1920–21. The book is an attempt to present some then-current mathematical thought to "contribute to a more just appreciation of mathematics by a wider range of people than just the specialists." It differentiates between two tendencies in mathematics and any other scientific research: on the one hand, toward abstraction and logical relations, correlating the subject matter in a systematic and orderly manner, and on the other hand an intuitive approach, which moves toward a more immediate grasp of and a "live rapport" with the same material. Further he asserts that intuitive understanding actually plays a major role for the researcher as well as anyone who wishes to study and appreciate Geometry.
Contents
Topics covered by the chapters in the book include the Leibniz formula for , configurations of points and lines with equally many points on each line and equally many lines through each point,
curvature and non-Euclidean geometry, mechanical linkages, the classification of manifolds by their Euler characteristic, and the four color theorem.
Response
The Mathematical Association of America said about the book, "this book is a masterpiece — a delightful classic that should never go out of print". Physics Today called it "a readable exposition of modern geometry and its relation to other branches of mathematics". The Scientific Monthly said about it "has been a classic for twenty years . . . Although it deals with elementary topics, it reaches the fringe of our knowledge in many directions".
References
External links
Geometry and the Imagination at the Internet Archive
1952 non-fiction books
Books about mathematics
1932 non-fiction books |
https://en.wikipedia.org/wiki/Locally%20nilpotent%20derivation | In mathematics, a derivation of a commutative ring is called a locally nilpotent derivation (LND) if every element of is annihilated by some power of .
One motivation for the study of locally nilpotent derivations comes from the fact that some of the counterexamples to Hilbert's 14th problem are obtained as the kernels of a derivation on a polynomial ring.
Over a field of characteristic zero, to give a locally nilpotent derivation on the integral domain , finitely generated over the field, is equivalent to giving an action of the additive group to the affine variety . Roughly speaking, an affine variety admitting "plenty" of actions of the additive group is considered similar to an affine space.
Definition
Let be a ring. Recall that a derivation of is a map satisfying the Leibniz rule for any . If is an algebra over a field , we additionally require to be -linear, so .
A derivation is called a locally nilpotent derivation (LND) if for every , there exists a positive integer such that .
If is graded, we say that a locally nilpotent derivation is homogeneous (of degree ) if for every .
The set of locally nilpotent derivations of a ring is denoted by . Note that this set has no obvious structure: it is neither closed under addition (e.g. if , then but , so ) nor under multiplication by elements of (e.g. , but ). However, if then implies and if , then .
Relation to -actions
Let be an algebra over a field of characteristic zero (e.g. ). Then there is a one-to-one correspondence between the locally nilpotent -derivations on and the actions of the additive group of on the affine variety , as follows.
A -action on corresponds to an -algebra homomorphism . Any such determines a locally nilpotent derivation of by taking its derivative at zero, namely where denotes the evaluation at .
Conversely, any locally nilpotent derivation determines a homomorphism by
It is easy to see that the conjugate actions correspond to conjugat |
https://en.wikipedia.org/wiki/Civil%20Engineering%20Database | The Civil Engineering Database (CEDB) was created in 1994, and is maintained by American Society of Civil Engineers (ASCE). It is a free bibliographic database, containing 270,000-entries, for all ASCE publications including journals, conference proceedings, books, standards, manuals, magazines, and newspapers on all the disciplines of civil engineering. The coverage dates back to 1872.
See also
List of academic databases and search engines
References
Civil engineering
American Society of Civil Engineers |
https://en.wikipedia.org/wiki/SaferVPN | SaferVPN was a VPN service developed by Safer Social, Ltd.
History
SaferVPN was released in 2013 by Amit Bareket and Sagi Gidali. SaferVPN network infrastructure served as the basis of Bareket's and Gidali's next company, Perimeter 81. The service was acquired by J2 Global in 2019 Q3 and was eventually merged into StrongVPN.
Technology
SaferVPN utilized the protocols OpenVPN, PPTP, L2TP and IKEv2.
See also
Comparison of virtual private network services
References
Virtual private network services |
https://en.wikipedia.org/wiki/Genetic%20rescue | Genetic rescue is seen as a mitigation strategy designed to restore genetic diversity and reduce extinction risks in small, isolated and frequently inbred populations. It is largely implemented through translocation, a type of demographic rescue and technical migration that adds individuals to a population to prevent its potential extinction. This demographic rescue may be similar to genetic rescue, as each increase population size and/or fitness. This overlap in meaning has led some researchers to consider a more detailed definition for each type of rescue that details 'assessment and documentation of pre- and post-translocation genetic ancestry'. Not every example of genetic rescue is clearly successful and the current definition of genetic rescue does not mandate that the process result in a 'successful' outcome. Despite an ambiguous definition, genetic rescue is viewed positively, with many perceived successes.
History
The conceptual foundation of genetic rescue can be traced back to the work of geneticist Sewall Wright, who studied the effect of immigration among populations linked by gene flow. More recently, genetic rescue has been defined by scientific reviews as: "when population fitness, inferred from some demographic vital rate or phenotypic trait, increases by more than can be attributed to the demographic contribution of immigrants." Genetic mixing leading to fitness recovery could be described as "genetic rescue", but perpetuates the unclear differences between genetic rescue and pollution.
Genetic processes
When a species' population becomes too small, they are subject to genetic processes such as inbreeding depression from a lack of gene flow, allelic fixation from genetic drift, and loss of diversity. In combination these can lead to a decrease in population fitness, and increase the risk of extinction. Genetic rescue is a conservation tool which tries to address these genetic factors by moving genes from one population to another to increase |
https://en.wikipedia.org/wiki/Pixel%20Buds | The Pixel Buds is a line of wireless earbuds developed and marketed by Google. The first-generation Pixel Buds were launched on October 4, 2017, at the Made by Google launch event, and became available for preorder on the Google Store the same day. They have the Google Assistant built-in and support Google Translate.
The second-generation Pixel Buds (sometimes known as Pixel Buds 2 or Pixel Buds 2020 to distinguish them from the first-generation earbuds) were announced at the Pixel 4 hardware event on October 15, 2019. They were released on April 27, 2020 and debuted to positive reviews.
In June 2021, Google announced the Pixel Buds A-Series, a mid-range variant of the second-generation Pixel Buds. In May 2022, Google announced the Pixel Buds Pro, a premium variant of the Pixel Buds with additional features including active noise cancellation.
First-generation
The Pixel Buds were announced at Google's annual hardware event on October 4, 2017, alongside its second-generation Pixel 2 smartphone. Color choices for the Pixel Buds complemented the Pixel 2, and carried the same names: Just Black, Clearly White, and Kinda Blue, referring to the color of the circular plastic cap visible in the ear. After the second-generation Pixel Buds were announced in October 2019, Google removed the first-generation from its store.
Physical design
The industrial design team was led by Gina Reimann.
The first-generation Pixel Buds consist of two earbuds linked by a fabric-covered cord, which connect wirelessly over a Bluetooth 4.2 connection. The earbuds are an "open-air" design, where the driver rests just outside the user's ear canal, and there is relatively little isolation from outside sounds. Each earbud is secured physically into the user's concha by a short loop of the cord; the length of the loop is individually adjustable to better fit each user. The earbuds are powered by a 120 mA-hr battery stored in the left earbud, and provide five hours of listening time before needin |
https://en.wikipedia.org/wiki/EPrivacy%20Regulation | The ePrivacy Regulation (ePR) is a proposal for the regulation of various privacy-related topics, mostly in relation to electronic communications within the European Union. Its full name is "Regulation of the European Parliament and of the Council concerning the respect for private life and the protection of personal data in electronic communications and repealing Directive 2002/58/EC (Regulation on Privacy and Electronic Communications)." It would repeal the Privacy and Electronic Communications Directive 2002 (ePrivacy Directive) and would be lex specialis to the General Data Protection Regulation. It would particularise and complement the latter in respect of privacy-related topics. Key fields of the proposed regulation are the confidentiality of communications, privacy controls through electronic consent and browsers, and cookies.
The history of the regulation goes back to January 2017 when the European Commission proposed the ePrivacy Regulation. The intention was that it would sit alongside the EU GDPR (General Data Protection Regulation) when it was introduced on 25 May 2018. The scope is still under discussion. According to some proposals, it would apply to any business that processes data in relation to any form of online communication service, uses online tracking technologies, or engages in electronic direct marketing.
The proposed penalties for noncompliance would be up to €20 million or, in the case of an undertaking, up to 4% of the total worldwide annual turnover, whichever is higher. The ePrivacy Regulation originally was intended to come in effect on 25 May 2018, together with the GDPR, but has still not been adopted.
Difference between Regulation and Directive
The (new) ePrivacy Regulation will repeal the (current) ePrivacy Directive.
Contrary to an EU Directive, an EU Regulation is a legal act of the European Union that becomes immediately effective as law in all member states simultaneously.
The current ePrivacy Directive is a legal act of |
https://en.wikipedia.org/wiki/BBE-like%20enzymes | Berberine bridge enzyme-like (BBE-like enzymes) form a subgroup of the superfamily of FAD-linked oxidases (SCOPe d.58.32), structurally characterized by a typical fold observed initially for vanillyl-alcohol oxidase (VAO). This proteins are part of a multigene family (PF08031) that can be found in plants, fungi and bacteria.
BBE-like enzymes family form a large subgroup that have a special C-terminal structural element adjacent to the substrate binding region. An homonym of this family is the (S)-reticuline oxidase or berberine bridge enzyme from California poppy (Eschscholzia californica), the responsible of catalyzing the conversion of (S)-reticuline to (S)-scoulerine. This conversion is made by an oxidative ring closure reaction. The product of this reaction is the C-C bond and is referred to as the berberine bridge. Also, marks a branch point in the biosynthesis of benzylisoquinoline alkaloids.
As mentioned above, BBE-like enzymes are in the large family of FAD-linked oxidases. Regarding the structure of this particular family, they have a FAD binding module formed by the N- and C- terminal parts of the protein. There is a substrate binding module that, in collaboration with isoalloxazine ring of FAD, disposes the environment for efficient substrate binding and oxidation.
Purification process
Cell cultures of Berberis beaniana (B. beaniana), which in this certain experiment are taken as an example, were harvested 10–12 days, contained large amounts of proto-berberines, mainly jatrorrhizine. These quaternary alkaloids have a strong inhibitory effect on the BBE, so they had to be removed. In order to eliminate most of these interfering cationic substances, the enzyme solution was treated first with carboxymethyl-Sepharose and subsequently with dextrancoated charcoal.
After that, the resulting solution was fractionated using standard procedures and generated, after isoelectric focusing, a single protein band in SDS gel electrophoresis. In the end, the obtained |
https://en.wikipedia.org/wiki/BT.1120 | BT.1120 is a digital interface standard for HDTV studio signals published by the International Telecommunication Union. , the current version of BT.1120 is BT.1120-8.
References
Video signal
High-definition television
Television technology
Television terminology |
https://en.wikipedia.org/wiki/Advances%20in%20Group%20Theory%20and%20Applications | Advances in Group Theory and Applications (AGTA) is a peer reviewed, open access research journal in mathematics, specifically group theory. It was founded in 2015 by the council of the no-profit association AGTA - Advances in Group Theory and Applications, and is published by Aracne.
The journal is composed of three sections. The main one contains mathematical research papers, while the two other sections are respectively devoted to historical papers and open problems.
The journal is published as a diamond open access journal, meaning that the content is immediately freely available to the readers, and the authors do not have to pay any author publication fees.
The journal is abstracted and indexed by Mathematical Reviews and Zentralblatt MATH.
Sections
ADV – The History behind Group Theory
The purpose of this section is to present historical documents, biographical notes and discussions on relevant aspects of group theory and its applications.
ADV – Perspectives in Group Theory
The open problems submitted to the journal are published in this section.
Reinhold Baer Prize sponsorship
The journal started co-sponsoring the Reinhold Baer Prize in 2017.
References
External links
Advances in Group Theory and Applications at Aracne
Journal website
Mathematics journals
Open access journals
Academic journals established in 2015 |
https://en.wikipedia.org/wiki/Reception%20and%20criticism%20of%20WhatsApp%20security%20and%20privacy%20features | This article provides a detailed chronological account of the historical reception and criticism of security and privacy features in the WhatsApp messaging service.
2011
On May 20, 2011, an unidentified security researcher from the Netherlands under the pseudonym "WhatsappHack" published a method to hijack WhatsApp accounts using a flaw in the authentication process, to the Dutch websites Tweakers.net and GeenStijl. The method involved trying to log in to a person's account from another phone number and intercepting the verification text message that would be sent out. "WhatsappHack" provided methods to accomplish this on both Symbian and Android operating systems. One day after the publication of the articles, WhatsApp issued a patch to both the Android and Symbian clients.
In May 2011, another security hole was reported which left communication through WhatsApp susceptible to packet analysis. WhatsApp communications data was sent and received in plaintext, meaning messages could easily be read if packet traces were available.
2012
In May 2012 security researchers noticed that new updates of WhatsApp sent messages with encryption, but described the cryptographic method used as "broken." In August of the same year, the WhatsApp support staff stated that messages sent in the "latest version" of the WhatsApp software for iOS and Android (but not BlackBerry, Windows Phone, and Symbian) were encrypted, but did not specify the cryptographic method.
On January 6, 2012, an unknown hacker published a website that made it possible to change the status of any WhatsApp user, so long as the phone number associated with the user's account was known. On January 9, WhatsApp reported that it had resolved the problem. In reality, WhatsApp's solution had been to block the website's IP address, which had allowed a Windows tool to be made that could accomplish the same thing. This problem has since been resolved by the institution of an IP address check on currently logged-in sess |
https://en.wikipedia.org/wiki/ABACABA%20pattern | The ABACABA pattern is a recursive fractal pattern that shows up in many places in the real world (such as in geometry, art, music, poetry, number systems, literature and higher dimensions). Patterns often show a DABACABA type subset. AA, ABBA, and ABAABA type forms are also considered.
Generating the pattern
In order to generate the next sequence, first take the previous pattern, add the next letter from the alphabet, and then repeat the previous pattern. The first few steps are listed here. A generator can be found here
ABACABA is a "quickly growing word", often described as chiastic or "symmetrically organized around a central axis" (see: Chiastic structure and Χ). The number of members in each iteration is , the Mersenne numbers ().
Gallery
See also
Arch form
Farey sequence
Rondo
Sesquipower
Notes
References
External links
Naylor, Mike: abacaba.org
Fractals |
https://en.wikipedia.org/wiki/Datatron | The Datatron is a family of decimal vacuum tube computers developed by ElectroData Corporation and first shipped in 1954. The Datatron was later marketed by Burroughs Corporation after Burroughs acquired ElectroData in 1956. The Burroughs models of this machine were still in use into the 1960s.
History
Consolidated Electrodynamics Corporation (CEC), ElectroData's parent corporation, first pre-announced the Datatron in 1952 as the "CEC 30-201". Known also as CEC 30-203 (ElectroData 203), ElectroData 204 or 205, Burroughs 205 (different names signify the development and addition of new peripherals).
The first systems were equipped with an "Electrodata 203" processor and were shipped to the Jet Propulsion Laboratory
(JPL) and the National Bureau of Standards (NBS) in 1954. That same year design began on the "30-240" processor, enhanced to support magnetic tape. The name "Datatron" was first used in 1955.
Description
The Datatron has a word size of ten decimal digits plus a sign. Character data occupies two digits per character. A magnetic drum is used for memory. The drum rotates at 3570 rotations per minute (RPM) and stores 4000 words on 20 tracks (called bands). It weighed about . A later model, the Burroughs 220, added a small amount of magnetic core memory. A later model, the Datatron 205 was sold by Burroughs as the Burroughs 205.
References
External links
Photo of Datatron system at Georgia Institute of Technology in 1959
ElectroData/Burroughs Datatron 205 Emulator
1950s computers
Vacuum tube computers
Decimal computers |
https://en.wikipedia.org/wiki/Howson%20property | In the mathematical subject of group theory, the Howson property, also known as the finitely generated intersection property (FGIP), is the property of a group saying that the intersection of any two finitely generated subgroups of this group is again finitely generated. The property is named after Albert G. Howson who in a 1954 paper established that free groups have this property.
Formal definition
A group is said to have the Howson property if for every finitely generated subgroups of their intersection is again a finitely generated subgroup of .
Examples and non-examples
Every finite group has the Howson property.
The group does not have the Howson property. Specifically, if is the generator of the factor of , then for and , one has . Therefore, is not finitely generated.
If is a compact surface then the fundamental group of has the Howson property.
A free-by-(infinite cyclic group) , where , never has the Howson property.
In view of the recent proof of the Virtually Haken conjecture and the Virtually fibered conjecture for 3-manifolds, previously established results imply that if M is a closed hyperbolic 3-manifold then does not have the Howson property.
Among 3-manifold groups, there are many examples that do and do not have the Howson property. 3-manifold groups with the Howson property include fundamental groups of hyperbolic 3-manifolds of infinite volume, 3-manifold groups based on Sol and Nil geometries, as well as 3-manifold groups obtained by some connected sum and JSJ decomposition constructions.
For every the Baumslag–Solitar group has the Howson property.
If G is group where every finitely generated subgroup is Noetherian then G has the Howson property. In particular, all abelian groups and all nilpotent groups have the Howson property.
Every polycyclic-by-finite group has the Howson property.
If are groups with the Howson property then their free product also has the Howson property. More generally, the Howson property i |
https://en.wikipedia.org/wiki/PostmarketOS | postmarketOS (abbreviated as pmOS) is an operating system primarily for smartphones, based on the Alpine Linux distribution.
postmarketOS was launched on 26 May 2017 with the source code available on GitHub before migrating to GitLab in 2018. It is capable of running different X and Wayland based user interfaces, such as Plasma Mobile, MATE, GNOME 3, and XFCE; later updates added support for Unity8 and Phosh. It is also capable of running Docker, if the device specific kernel has cgroups and relevant configs enabled. The project aims to provide a ten-year lifecycle for smartphones.
Architecture
Unlike many other projects porting conventional Linux distributions to Android phones, postmarketOS does not use the Android build system or userspace. Each phone has only one unique package, and flashable installation images are generated using the pmbootstrap tool. The project intends to support the mainline Linux kernel on all phones in the future, instead of the often outdated Android-specific fork, to reduce the potential for security exploits. A few devices can boot into the mainline kernel already. The project aims to support Android apps, originally through the use of Anbox, which was replaced by Waydroid since postmarketOS v21.12.
Alpine Linux was chosen as the base distribution due to its low storage requirements, making it more suitable for older devices. Excluding the kernel, a base installation takes up approximately 6 MB.
State of development
Features
Different tools have been published by the project, including:
pmbootstrap, a utility to help the process of development with cross compilation;
osk-sdl, a virtual keyboard to allow decryption of a password during startup (on a device with full disk encryption);
charging-sdl, an application contained in the initramfs to display an animation when the phone is charging while off.
Device support
As of May 2020, over two hundred devices are able to boot the operating system, including 92 with WiFi support. |
https://en.wikipedia.org/wiki/Orchid%20mycorrhiza | Orchid mycorrhizae are endomycorrhizal fungi which develop symbiotic relationships with the roots and seeds of plants of the family Orchidaceae. Nearly all orchids are myco-heterotrophic at some point in their life cycle. Orchid mycorrhizae are critically important during orchid germination, as an orchid seed has virtually no energy reserve and obtains its carbon from the fungal symbiont.
The symbiosis starts with a structure called a protocorm. During the symbiosis, the fungus develops structures called pelotons within the root cortex of the orchid.
Many adult orchids retain their fungal symbionts throughout their life, although the benefits to the adult photosynthetic orchid and the fungus remain largely unexplained.
Seed germination
Orchids have several life stages. The first stage is the non-germinated orchid seed, the next stage is the protocorm, and the following stage is the adult orchid. Orchid seeds are very small (0.35mm to 1.50mm long), spindle-shaped, and have an opening at the pointed end. Each seed has an embryo that is undifferentiated and lacks root and shoot meristems. An orchid seed does not have enough nutritional support to grow on its own. Instead, it gets nutrients needed for germination from fungal symbionts in natural habitats. When the orchid seeds germinate they form intermediate structures called protocorms, young plants which have germinated but lack leaves and which consist mainly of parenchyma cells. Infected protocorms tend to develop an active meristem within a few days. In the adult stage, many orchids have a small amount of thick unbranched roots which results in a root system with a small surface area that is favorable to potentially mycotrophic tissue.
Orchids lacking chlorophyll, called achlorophyllous mycoheterotrophs, will retain their fungal symbionts their entire lives, relying on the fungus for carbon. The debate over whether fungal symbiosis is necessary for the orchid is an old one, as Noel Bernard first proposed orc |
https://en.wikipedia.org/wiki/Biology%20of%20trust | The biology of trust is the study of physiological mechanisms involved in mediating trust in social attachments. It has been studied in terms of genetics, endocrinology and neurobiology.
Trust is the intentional choice to believe the input of strangers because one believes they know the truth and have one's best interest at heart. Trust is important in creating social attachments.
Social bonds is a characteristic present in many mammals and other vertebrae species. However, there exists a paradox in the formation of social bonds in humans- while there are benefits, drawbacks, such as judgment, vulnerabilities to harmful physical and emotional hurt do exist. And overarching all of this is trust, which is marked by the intentional choice to rely on another individual for an underlying purpose, despite drawbacks- a factor in social bonds with biological implications.
Neural Mechanisms
Neuropeptides, specifically oxytocin (OT) and arginine-vasopressin (AVP), have been shown to be involved in physiological mechanisms of social behavior. Sex hormones, have also been correlated. The involvement of OT and AVP in trust and social attachment can be attributed the fact that both molecules can be released as neurotransmitters or hormones throughout the body. OT and AVP act as neurotransmitters when released directly by the hypothalamus; they act as neurohormones when released peripherally by the pituitary gland. So, both AVP and OT are peripheral (functioning throughout the body) and central (functioning within the brain).
Both social bonding and social attachment involve OT. In female rats that had OT injected directly into the brain, studies found that the OT rats exhibited full maternal behavior towards foster pups. In studies involving human subjects, increases in OT were observed in subjects who received intentional trust signals in a controlled trust game. When an OT receptor antagonist was injected in rats, it was found that there was a decrease in social recognit |
https://en.wikipedia.org/wiki/Prometheus%20%28rocket%20engine%29 | The Prometheus rocket engine is an ongoing European Space Agency (ESA) development effort begun in 2017 to create a reusable methane-fueled rocket engine for use on the Themis reusable rocket demonstrator and Ariane Next, the successor to Ariane 6, and possibly a version of Ariane 6 itself.
Prometheus is a backronym from the original French project designation PROMETHEE, standing for "Precursor Reusable Oxygen Methane cost Effective propulsion System", and for the Titan Prometheus, from Greek mythology, creator of humanity, and god of fire, known for giving fire to humanity in defiance of the gods.
By 2020, the development program was funded, and is being developed for the ESA by Ariane Group.
The engine is aimed to be reusable with substantially lower costs than traditional engines manufactured in Europe. The cost goal is to manufacture the Prometheus engine at one-tenth the cost of the Ariane 5's first-stage engine.
General characteristics
The engine is planned to have the following features:
Methane–oxygen propellant.
Extensive use of metal 3D printing (up to 50% of the engine).
Open gas-generator cycle.
980 kN of thrust (~100 tonnes), variable from 30% to 110% thrust.
chamber pressure.
360 s specific impulse (I).
Reusable 3 to 5 times.
Around 1 million euros production cost.
History
The European Space Agency (ESA) began funding Prometheus engine development in June 2017 with provided through the Future Launchers Preparatory Programme, 63% of which coming from France.
By June 2017, Patrick Bonguet, lead of the Ariane 6 launch vehicle program at Arianespace, indicated that it was possible the Prometheus engine could find a use on a future version of the expendable Ariane 6 launcher. In this scenario, a "streamlined version of Vulcain rocket engine called Vulcain 2.1 would have the same performance as Vulcain 2". The expendable Ariane 6 was then expected to make an initial launch in 2020.
By June 2020, the ESA was on board with this plan and ha |
https://en.wikipedia.org/wiki/Developmental%20bioelectricity | Developmental bioelectricity is the regulation of cell, tissue, and organ-level patterning and behavior by electrical signals during the development of embryonic animals and plants. The charge carrier in developmental bioelectricity is the ion (a charged atom) rather than the electron, and an electric current and field is generated whenever a net ion flux occurs. Cells and tissues of all types use flows of ions to communicate electrically. Endogenous electric currents and fields, ion fluxes, and differences in resting potential across tissues comprise a signalling system. It functions along with biochemical factors, transcriptional networks, and other physical forces to regulate cell behaviour and large-scale patterning in processes such as embryogenesis, regeneration, and cancer suppression.
Overview
Developmental bioelectricity is a sub-discipline of biology, related to, but distinct from, neurophysiology and bioelectromagnetics. Developmental bioelectricity refers to the endogenous ion fluxes, transmembrane and transepithelial voltage gradients, and electric currents and fields produced and sustained in living cells and tissues. This electrical activity is often used during embryogenesis, regeneration, and cancer suppression—it is one layer of the complex field of signals that impinge upon all cells in vivo and regulate their interactions during pattern formation and maintenance. This is distinct from neural bioelectricity (classically termed electrophysiology), which refers to the rapid and transient spiking in well-recognized excitable cells like neurons and myocytes (muscle cells); and from bioelectromagnetics, which refers to the effects of applied electromagnetic radiation, and endogenous electromagnetics such as biophoton emission and magnetite.
The inside/outside discontinuity at the cell surface enabled by a lipid bilayer membrane (capacitor) is at the core of bioelectricity. The plasma membrane was an indispensable structure for the origin and evolut |
https://en.wikipedia.org/wiki/Iodine%20Satellite | Iodine Satellite (iSat) is a technology demonstration satellite of the CubeSat format that will undergo high changes in velocity (up to 300 meters/second) from a primary propulsion system by using a Hall thruster with iodine as the propellant. The spacecraft will also perform changes of its orbital altitude, and demonstrate deorbit capabilities to reduce space junk.
iSat was being developed by NASA's Glenn Research Center, and was initially planned as a secondary payload for launch in mid-2018, but launch was delayed to allow for the propulsion system development to mature. The mission is planned to last one year before deorbit.
Spacecraft
Electrically powered spacecraft propulsion uses electricity, typically from solar panels, to accelerate the propellant and produce thrust. The technology can be scaled up to be used on small satellites up to . iSat will also demonstrate advanced power management and thermal control capabilities developed for spacecraft of its size.
The satellite is a 12U CubeSat format, with dimensions of about 20 cm × 20 cm × 30 cm. Its solar arrays aim to produce 100 W.
Propulsion
The propulsion maturation is a partnership between NASA and the U.S. Air Force. iSat's iodine propulsion system consists of a 200 watt Hall thruster (BHT-200-I) developed by Busek Co, a cathode, a tank to store solid iodine, a power processing unit (PPU) and the feed system to supply the iodine. The cathode technology is planned to enable heaterless cathode conditioning, significantly increasing total system efficiency.
A key advantage to using iodine as a propellant is that it provides a high density times specific impulse, it is three times as fuel efficient as the commonly flown xenon, it may be stored in the tank as an unpressurized solid, and it is not a hazardous propellant. 1U with 5 kg of iodine on a 12U vehicle can provide a change of velocity of 4 km/s ΔV, perform a 20,000km altitude change, 30° inclination change from LEO, or an 80° inclination ch |
https://en.wikipedia.org/wiki/Post%20War%20Building%20Studies | The Post-War Building Studies are a set of technical reports published by the British Ministry of Works starting in 1944. The Directorate of Post-War Building was established in 1941 under Sir James West. The Directorate was charged with coordinating solutions for construction of housing to replace homes that had been destroyed as well as homes that had been deferred due to war. The Directorate reported to the Minister of Works, initially Lord Reith then later Lord Portal. The publications were produced by various committees (such as the Burt Committee) composed of architects, engineers, and representatives from the building industry. The studies standardized non-traditional methods of building construction including the use of pre-fabricated elements and poured concrete. A new standard system for wiring homes for electricity was described in report no. 11. The reports had a significant impact on the design and construction of buildings in the UK after the war and continue to be cited as references, though their recommendations on fire safety were later found to be insufficient as apartment buildings became taller. However, the BS 1363 power socket (another product of the studies) has proved long-lasting and is still in use in British homes today. While not made part of mandatory building codes and regulations, the reports provided technical guidance and information on application of non-traditional building techniques and materials while overcoming material and labour shortages.
Based on the experience following World War I, it was expected that housing construction demand would be very high after WWII ended, both due to pent-up demand that had not been fulfilled and also due to replacement or repair of housing that had been bombed during the war. Labour and material were expected to be in short supply. Interest in industrial methods, pre-fabrication and new materials was high during the period between the wars, and such publications as the Tudor Walters Rep |
https://en.wikipedia.org/wiki/Lug%20%28hinge%29 | Lugs are the loops (or protuberances) that exist on both arms of a hinge, featuring a hole for the axis of the hinge.
Hinges |
https://en.wikipedia.org/wiki/%C8%98tefan%20Emilian | Ștefan Emilian (August 8, 1819 – November 1899) was an Imperial Austrian-born Romanian mathematician and architect.
Born in Bonchida, Kolozs County (now Bonțida, Cluj County), in the Principality of Transylvania, he was given the surname Kertész as a child, although his birth name was Emilian. He attended high school in Sibiu. Then, from 1841 to 1845, he studied at the Academy of Fine Arts Vienna, graduating with an architect's degree. Additionally, from 1841 to 1843, he took courses at the Vienna Polytechnic Institute. Emilian returned home shortly before 1848, in time for the Transylvanian Revolution. Pursued by the authorities, he sought refuge in Wallachia. By 1850, he was back in Transylvania, where he taught mathematics at Brașov's Greek Orthodox High School. He remained there until 1858, a period during which he designed the new school building. Additionally, he was the architect for the first paper factory in Zărnești.
In 1858, he was invited to Iași, the capital of Moldavia, in order to teach drawing and geometry to the upper classes of Academia Mihăileană. Emilian remained there for two years, until the founding of the University of Iași. Additionally, he taught at the military officers' school and the technical school of arts and professions. At the new university, he was named full professor of descriptive geometry and linear perspective, remaining from October 1860 to October 1892, when he had to retire. Meanwhile, he designed the Iași anatomy institute, the Lipovan Church, and the church in Bosia. A single published book of his is known: the 1886 Curs practic de perspectivă liniară. Emilian's funeral eulogy was delivered by Alexandru Dimitrie Xenopol.
He married Cornelia Ederlly de Medve.
Notes
1819 births
1899 deaths
People from Cluj County
Romanian people in the Principality of Transylvania (1711–1867)
Emigrants from Austria-Hungary to Romania
Romanian mathematicians
Romanian architects
Romanian schoolteachers
Romanian revolutionaries
Romanian t |
https://en.wikipedia.org/wiki/Quantum%20Computation%20and%20Quantum%20Information | Quantum Computation and Quantum Information is a textbook about quantum information science written by Michael Nielsen and Isaac Chuang, regarded as a standard text on the subject. It is informally known as "Mike and Ike", after the candies of that name. The book assumes minimal prior experience with quantum mechanics and with computer science, aiming instead to be a self-contained introduction to the relevant features of both. (Lov Grover recalls a postdoc disparaging it with the remark, "The book is too elementary – it starts off with the assumption that the reader does not even know quantum mechanics.") The focus of the text is on theory, rather than the experimental implementations of quantum computers, which are discussed more briefly.
, the book has been cited over 39,000 times on Google Scholar. In 2019, Nielsen adapted parts of the book for his Quantum Country project.
Table of Contents (Tenth Anniversary Edition)
Chapter 1: Introduction and Overview
Chapter 2: Introduction to Quantum Mechanics
Chapter 3: Introduction to Computer Science
Chapter 4: Quantum Circuits
Chapter 5: The Quantum Fourier Transform and its Applications
Chapter 6: Quantum Search Algorithms
Chapter 7: Quantum Computers: Physical Realization
Chapter 8: Quantum Noise and Quantum Operations
Chapter 9: Distance Measures for Quantum Information
Chapter 10: Quantum Error-Correction
Chapter 11: Entropy and Information
Chapter 12: Quantum Information Theory
Appendix 1: Notes on Basic Probability Theory
Appendix 2: Group Theory
Appendix 3: The Solovay–Kitaev Theorem
Appendix 4: Number Theory
Appendix 5: Public Key Cryptography and the RSA Cryptosystem
Appendix 6: Proof of Lieb's Theorem
Bibliography
Index
Reviews
Peter Shor called the text "an excellent book". Lov Grover called it "the bible of the quantum information field". Scott Aaronson said about it, Mike and Ike' as it's affectionately called, remains the quantum computing textbook to which all others are compared. |
https://en.wikipedia.org/wiki/Cross%20section%20%28electronics%29 | In electronics, a cross section, cross-section, or microsection, is a prepared electronics sample that allows analysis at a plane that cuts through the sample. It is a destructive technique requiring that a portion of the sample be cut or ground away to expose the internal plane for analysis. They are commonly prepared for research, manufacturing quality assurance, supplier conformity, and failure analysis. Printed wiring boards (PWBs) and electronic components and their solder joints are common cross sectioned samples. The features of interest to be analyzed in cross section can be nanometer-scale metal and dielectric layers in semiconductors up to macroscopic features such as the amount of solder that has filled into a large, 0.125in (3.18mm) diameter plated through hole.
Preparation
Cross sections can be prepared by several methods typically chosen based on the scale of the feature of interest because the technique affects the smoothness of the final polish. Smoother polishes allow an analysis of smaller features but can also take longer or be more expensive to prepare. Cross sectioning hard materials such as alumina might require a different technique than a soft material like gold or soft plastic.
Mechanical grinding and polishing
Mechanical grinding and polishing is a common method of preparation to analyze features on the order of 1s to 10s of microns to macroscopic features. Samples may first be cut down in size, for example, around a via in a PWB or around a ceramic capacitor soldered to a PWB. Samples may be prepared by encapsulation in a rigid material such as epoxy to keep the sample intact during grinding and with a vacuum step to fill in air gaps and create a solid sample with no voids. However, cross sections of some samples can be prepared with no encapsulation.
Encapsulated samples are prepared using a rough grinding medium to remove material from the sample until just before the plane of interest is reached. Equipment can help automate the proce |
https://en.wikipedia.org/wiki/Mobirise | Mobirise is a freeware web design application that allows users to design and publish bootstrap websites without coding. Mobirise is essentially a drag and drop website builder, featuring various website themes. It is headquartered in Eindhoven, Netherlands.
History
On May 19, 2015 the first beta version 1.0 was released with the focus on no-coding web design and compliance to the Google mobile-friendly update.
On September 30, 2015, version 2.0 was released, which added drop-down menus, contact forms, animations, support for 3rd-party themes and extensions. Since version 3.0, added some new themes and extension and introduced support for Bootstrap 4.
On June 16, 2017, version 4.0 was released, which presented the new core engine, new interface and new default website theme.
In May 2018, there was released the updated 4.4 Android version of Mobirise.
On June 27, 2022, Mobirise developers released version 5.6.11 as their latest stable release.
References
External links
Mobirise on GitHub
HTML editors
Web development software
Freeware
2015 software
Responsive web design
Web design
Mobile web
MacOS software
Windows software
Cross-platform software |
https://en.wikipedia.org/wiki/International%20Ideographs%20Core | International Ideographs Core (IICore) is a subset of up to ten thousand CJK Unified Ideographs characters, which can be implemented on devices with limited memories and capability that make it not feasible to implement the full ISO 10646/Unicode standard.
History
The IICore subset was initially raised in the 21st meeting of the Ideographic Rapporteur Group (IRG) in Guilin during 17th-20 November in 2003, and is subsequently passed in the group's 22nd meeting in Chengdu in May 2004.
See also
Chinese character encoding
Han unification
References
External links
International Ideographs Core (IICORE) Comparison Utility
IICore development information
Chinese-language computing
Encodings of Japanese
Korean language
Unicode
Natural language and computing
Character encoding
Mobile computers |
https://en.wikipedia.org/wiki/Codewars | Codewars is an educational community for computer programming. On the platform, software developers train on programming challenges known as kata. These discrete programming exercises train a range of skills in a variety of programming languages, and are completed within an online integrated development environment. On Codewars the community and challenge progression is gamified, with users earning ranks and honor for completing kata, contributing kata, and quality solutions.
The platform is owned and operated by Qualified, a technology company that provides a platform for assessing and training software engineering skills.
History
Founded by Nathan Doctor and Jake Hoffner in November 2012, the project initially began at a Startup Weekend competition that year, where it was prototyped. It was awarded first place in that competition, drawing the attention of engineers, and funding interest from two of the judges Paige Craig (angel investor) and Brian Lee (entrepreneur).
After building the first production iteration of the platform, it was launched to the Hacker News community, receiving significant attention for its challenge format and signing up approximately 10,000 users within that weekend.
See also
CodeFights
CodinGame
Competitive programming
HackerRank
External links
AngelList profile
Programming contests
Computer programming
American educational websites
References |
https://en.wikipedia.org/wiki/Erwin%20Lutwak | Erwin Lutwak (born 9 February 1946, Chernivtsi, now Ukraine), is a mathematician. Lutwak is professor emeritus at the Courant Institute of Mathematical Sciences at New York University in New York City. His main research interests are convex geometry and its connections with analysis and information theory.
Biography
He spent the earliest years of his childhood in the Soviet Union, Romania, Israel, Italy, and Venezuela before he settled in Brooklyn when he was ten. He graduated from the Polytechnic Institute of Brooklyn, now New York University Tandon School of Engineering with a B.S. in 1968, a M.S. in 1972 and with a Ph.D. in 1974. Before he became professor at the Courant Institute at NYU, he was a professor at New York University Tandon School of Engineering. His first position in 1975 was at the Polytechnic Institute of New York (which was created as a result of the merger of the Polytechnic Institute of Brooklyn and the NYU School of Engineering).
He is a member of the editorial boards of the Advances in Mathematics,
the Canadian Journal of Mathematics, the Canadian Mathematical Bulletin, and the Cambridge University Press Encyclopedia of Mathematics and its Applications.
He is an Honorary Editor at Advanced Nonlinear Studies (De Gruyter).
Work
Erwin Lutwak is known for his Dual Brunn Minkowski Theory,
his notion of intersection body and his contribution to the solution of the Busemann–Petty problem, for proving the long-conjectured upper-semicontinuity of affine surface area, his contributions to the Lp Brunn Minkowski Theory and, in particular, his Lp Minkowski problem and its solution in important cases.
Honors
Lutwak became an Inaugural Fellow of the American Mathematical Society in 2012.
He received an honorary doctorate of the TU Wien in 2014.
Personal life
Dr. Lutwak is married to Nancy Lutwak, M.D.. They have one daughter, Hope Lutwak, who graduated with a Bachelor of Science in 2018 from the Massachusetts Institute of Technology. The family r |
https://en.wikipedia.org/wiki/Antisperm%20antibodies | Antisperm antibodies (ASA) are antibodies produced against sperm antigens.
Types
Antisperm antibodies are immunoglobulins of IgG, IgA, and/or IgM, which are directed against sperm antigens. ASA can be detected in ejaculate, cervical mucus, follicular fluid, and blood serum of both males and females. While IgG and IgA might be present in blood serum and/or genital tract fluids, IgM is only present in blood serum. IgG occurring in genital tract fluids is either produced locally or transuded from blood serum, whereas IgA (secretory type) is always produced locally.
Causes
Traditionally, the breakdown of the blood-testis barrier had been established as the cause of ASA production. This mechanism had been advocated in testicular trauma and surgery, orchitis (mumps), varicocele, bacterial infections (epididymitis, prostatitis), testicular cancer, and unprotected anal intercourse. However, the association between aforementioned conditions and ASA production is controversial. Only chronic obstruction, most typically represented by vasectomy followed by vasectomy reversal, is the only one condition leading constantly to high and permanent ASA titers. Apart from breaching of blood-testis barrier, epididymal distension, raised intraluminal pressure, and sperm granuloma formation leading spermatozoal phagocytosis seem to be contributing factors.
As of 2017, it is unclear how or why women generally do not develop ASA, and why some women do develop them; the clearest correlations are that women whose male partners have ASA in their semen are more likely to have ASA, and women with ASA tend to react only to their partner's sperm and not to other men's sperm. The hypotheses for how women form ASA, as of 2017, includes cross-reactivity with microbial antigens, antibodies raised against ASA in their partner's semen, and a cytokine-driven immune response to ASA in their partner's semen. In women, spermatozoa in the genital tract after intercourse are not a factor in the producti |
https://en.wikipedia.org/wiki/Boolean%20differential%20calculus | Boolean differential calculus (BDC) (German: (BDK)) is a subject field of Boolean algebra discussing changes of Boolean variables and Boolean functions.
Boolean differential calculus concepts are analogous to those of classical differential calculus, notably studying the changes in functions and variables with respect to another/others.
The Boolean differential calculus allows various aspects of dynamical systems theory such as
automata theory on finite automata
Petri net theory
supervisory control theory (SCT)
to be discussed in a united and closed form, with their individual advantages combined.
History and applications
Originally inspired by the design and testing of switching circuits and the utilization of error-correcting codes in electrical engineering, the roots for the development of what later would evolve into the Boolean differential calculus were initiated by works of Irving S. Reed, David E. Muller, David A. Huffman, Sheldon B. Akers Jr. and (, ) between 1954 and 1959, and of Frederick F. Sellers Jr., Mu-Yue Hsiao and Leroy W. Bearnson in 1968.
Since then, significant advances were accomplished in both, the theory and in the application of the BDC in switching circuit design and logic synthesis.
Works of , Marc Davio and in the 1970s formed the basics of BDC on which , and further developed BDC into a self-contained mathematical theory later on.
A complementary theory of Boolean integral calculus (German: ) has been developed as well.
BDC has also found uses in discrete event dynamic systems (DEDS) in digital network communication protocols.
Meanwhile, BDC has seen extensions to multi-valued variables and functions as well as to lattices of Boolean functions.
Overview
Boolean differential operators play a significant role in BDC. They allow the application of differentials as known from classical analysis to be extended to logical functions.
The differentials of a Boolean variable models the relation:
There are no constraint |
https://en.wikipedia.org/wiki/Bitcoin%20Gold | Bitcoin Gold (BTG) is a cryptocurrency. It is a hard fork of Bitcoin, the open source cryptocurrency. It is an open source, decentralized digital currency without a central bank or intermediary that can be sent from user to user on the peer-to-peer Bitcoin Gold network.
The stated purpose of the hard fork is to change the proof of work algorithm so that ASICs (Application-Specific Integrated Circuits) which are used to mine Bitcoin cannot be used to mine the Bitcoin Gold blockchain in the hopes that enabling mining on commonly available graphics cards will democratize and decentralize the mining and distribution of the cryptocurrency.
The project began as a community-driven effort with six co-founders, half of whom continue to serve on the project's Board (including Lead Developer, Hang Yin.)
History
Bitcoin Gold hard forked from the Bitcoin blockchain on October 24, 2017, at block height 491407.
In July 2018, Bitcoin Gold implemented a new mining algorithm. The actual algorithm that was developed by Zcash (now, Electric Coin Company) was based on parameter set <200,9>. Bitcoin Gold has modified this algorithm and is now adopting parameter set <144,5>. This new algorithm is called Equihash-BTG. The new algorithm requires more memory than the one that was originally developed by Zcash.
Network attacks
Soon after the launch, the website came under a distributed denial of service attack, and received criticism from Coinbase and Bittrex for being hastily put together, as well as including a developer pre-mine.
In May 2018, Bitcoin Gold was hit by a 51% hashing attack by an unknown actor. This type of attack makes it possible to manipulate the blockchain ledger on which transactions are recorded, and to spend the same digital coins more than once. During the attack, 388,000 BTG (worth approximately US$18 million) was stolen from several cryptocurrency exchanges. Bitcoin Gold was later delisted from Bittrex, after the team refused to help pay some damages.
Bitco |
https://en.wikipedia.org/wiki/DeaDBeeF | DeaDBeeF is an audio player software available for Windows, Linux and other Unix-like operating systems. An ad-supported Android version is available, but has not been updated since 2017. DeaDBeeF is free and open-source software, except on Android.
History
The player was first published in August 2009. Its author cited dissatisfaction with existing music players under Linux as the main reason for writing DeaDBeeF. The name is a reference to the magic number 0xDEADBEEF.
Characteristics
Among DeaDBeeF's functionalities are included:
Support for formats MP3, FLAC, APE, TTA, Vorbis, WavPack, Musepack, AAC, ALAC, WMA, WAV, DTS, audio CD, many forms of module files and music from game consoles. TAK and Opus are supported via ffmpeg/libav.
Cuesheet support, both in built-in format and external files. iso.wv support.
Character encodings Windows-1251 and ISO 8859-1 are supported in addition to UTF-8.
The program doesn't have any dependencies on GNOME, KDE or gstreamer.
Plug-in architecture.
Gapless playback.
Customizable systemd notifications (OSD).
Read and write support for playlists in format M3U and PLS.
Network playback of podcasts using SHOUTcast, Icecast, MMS, HTTP and FTP.
Customizable global keyboard shortcuts.
Tag support (read and write) for ID3v1, ID3v2, APEv2, Vorbis comments, iTunes.
Mass tagging and flexible tagging (custom tags).
High-quality resampling.
Bit-perfect output under certain configurations.
Sound output via ALSA, PulseAudio and OSS.
Scrobbling to last.fm, libre.fm or any GNU FM server.
En masse transcoder.
ReplayGain support.
Multi-channel playback.
18-band equalizer.
Simple command-line user interface as well as graphical user interface implemented in GTK+ (version 2 or 3). The GUI is fully customizable.
See also
Comparison of audio player software
References
External links
DeaDBeeF Player on Google Play
Audio players
2009 software
Android (operating system) software
Free software programmed in C
Audio player |
https://en.wikipedia.org/wiki/KRACK | KRACK ("Key Reinstallation Attack") is a replay attack (a type of exploitable flaw) on the Wi-Fi Protected Access protocol that secures Wi-Fi connections. It was discovered in 2016 by the Belgian researchers Mathy Vanhoef and Frank Piessens of the University of Leuven. Vanhoef's research group published details of the attack in October 2017. By repeatedly resetting the nonce transmitted in the third step of the WPA2 handshake, an attacker can gradually match encrypted packets seen before and learn the full keychain used to encrypt the traffic.
The weakness is exhibited in the Wi-Fi standard itself, and not due to errors in the implementation of a sound standard by individual products or implementations. Therefore, any correct implementation of WPA2 is likely to be vulnerable. The vulnerability affects all major software platforms, including Microsoft Windows, macOS, iOS, Android, Linux, OpenBSD and others.
The widely used open-source implementation wpa_supplicant, utilized by Linux and Android, was especially susceptible as it can be manipulated to install an all-zeros encryption key, effectively nullifying WPA2 protection in a man-in-the-middle attack. Version 2.7 fixed this vulnerability.
The security protocol protecting many Wi-Fi devices can essentially be bypassed, potentially allowing an attacker to intercept sent and received data.
Details
The attack targets the four-way handshake used to establish a nonce (a kind of "shared secret") in the WPA2 protocol. The standard for WPA2 anticipates occasional Wi-Fi disconnections, and allows reconnection using the same value for the third handshake (for quick reconnection and continuity). Because the standard does not require a different key to be used in this type of reconnection, which could be needed at any time, a replay attack is possible.
An attacker can repeatedly re-send the third handshake of another device's communication to manipulate or reset the WPA2 encryption key. Each reset causes data to be encry |
https://en.wikipedia.org/wiki/Qualified%20website%20authentication%20certificate | A qualified website authentication certificate (QWAC certificate) is a qualified digital certificate under the trust services defined in the European Union eIDAS Regulation.
A 2016 European Union Agency for Cybersecurity report proposed six strategies and twelve recommended actions as an escalated approach that targets the most important aspects viewed as critical for improving the website authentication market in Europe and successfully introducing qualified website authentication certificates as a means to increase transparency in this market.
QWAC in the context of other standards
There are different types of website authentication certificates, which is distinguished by the content contained within the Subject of the certificate: Domain Validated (DV), Organization Validated (OV) and Extended Validation (EV).
Another distinction that can be made is the number of domains that are secured by the certificate: Single domain, wildcard, multi domain. Extended Validation certificates have a distinct set of issuance policies, requiring an enhanced level of certificate subscriber identity verification as prescribed by the CA/Browser Forum, thus they have the highest level of identity assurance of all TLS certificates in the marketplace. The EV certificate was distinguished in the browser by the presence of a green address bar, green text, and presence of legal business name in URL depending on which browser was used. Research conducted by Google and UC Berkeley identified that users didn't notably alter behavior based on the presence or absence of these indicators. The results of this research motivated Google, which commanded significant browser market share, to discontinue differentiation between the different certificate types. The EU approached the CABF in 2018 requesting to partner on updating existing EV requirements to include additional Subject information within the EV certificate. Google, followed by other browsers, was already in the process of deprecating |
https://en.wikipedia.org/wiki/Dye-and-pry | Dye-n-Pry, also called Dye And Pry, Dye and Pull, Dye Staining, or Dye Penetrant, is a destructive analysis technique used on surface mount technology (SMT) components to either perform failure analysis or inspect for solder joint integrity. It is an application of dye penetrant inspection.
Method
Dye-n-Pry is a useful technique in which a dye penetrant material is used to inspect for interconnect failures in integrated circuits (IC). This is mostly commonly done on solder joints for ball grid array (BGA) components, although in some cases it can be done with other components or samples. The component of interest is submerged in a dye material, such as red steel dye, and placed under vacuum. This allows the dye to flow underneath the component and into any cracks or defects. The dye is then dried in an oven (preferably overnight) to prevent smearing during separation, which could lead to false results. The part of interest is mechanically separated from the printed circuit board (PCB) and inspected for the presence of dye. Any fracture surface or interface will have dye present, indicating the presence of cracks or open circuits. IPC-TM-650 Method 2.4.53 specifies a process for dye-n-pry.
Use in failure analysis of electronics
Dye-n-Pry is a useful failure analysis technique to detect cracking or open circuits in BGA solder joints. This has some practical advantages over other destructive techniques, such as cross sectioning, as it can inspect a full ball grid array which may consist of hundreds of solder joints. Cross sectioning, on the other hand, may only be able to inspect a single row of solder joints and requires a better initial idea of the failure site.
Dye-n-pry can be useful for detecting several different failure modes. This includes pad cratering or solder joint fracture from mechanical drop/shock, thermal shock, or thermal cycling. This makes it useful technique to incorporate into a reliability test plan as part of the post test failure inspection. |
https://en.wikipedia.org/wiki/Bison%20industrialised%20building%20system | The Bison industrialised building system is a precast concrete building system used in high rise flats, developed by Bison Manufacturing Ltd, Dartford, Kent which had been founded in 1919 to build military pill-boxes.
The Bison wall-frame construction system was a construction method used in tower block construction. It was launched in 1963 by Concrete Ltd who set up factories across the UK to pre-fabricate the parts it.
It was not a frame structure as such, instead pre-cast concrete panels formed the structure of high rise blocks. It evolved into a rapid construction method.
In tower blocks over 12 storeys in height, all of the walls were loadbearing - external and internal. Whilst there were no partition walls, the internal walls were still thinner at 6 inches in thickness. Two-bedroom flats could be constructed out of 21 pre-cast concrete pieces. The bathroom and toilet elements could be constructed from a similarly few number of pre-fabricated pieces. The lift shaft and staircases could be constructed out of pieces that were 3 storeys high. The method was limited in that it was only really practical for two and three-bedroom flats.
See also
Chelmsley Wood
References
External links
Company heritage page
Contains text from an article on wikia cc-by-sa
Building engineering |
https://en.wikipedia.org/wiki/List%20of%20quantum%20processors | This list contains quantum processors, also known as quantum processing units (QPUs). Some devices listed below have only been announced at press conferences so far, with no actual demonstrations or scientific publications characterizing the performance.
Quantum processors are difficult to compare due to the different architectures and approaches. Due to this, published qubit numbers do not reflect the performance levels of the processor. This is instead achieved through benchmarking metrics such as quantum volume, randomized benchmarking or circuit layer operations per second (CLOPS).
Circuit-based quantum processors
These QPUs are based on the quantum circuit and quantum logic gate-based model of computing.
Annealing quantum processors
These QPUs are based on quantum annealing, not to be confused with digital annealing.
Analog quantum processors
These QPUs are based on analog Hamiltonian simulation.
See also
Quantum programming
Timeline of quantum computing and communication
References
Quantum computing
quantum processors |
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