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https://en.wikipedia.org/wiki/Paul%20Yeboah | Paul Yeboah (1970 – 2021) was an educator, farmer, permaculturist, community developer, and social entrepreneur. Yeboah founded and coordinated the Ghana Permaculture Institute and Network in Techiman, Ghana, West Africa. It is located in the Brong-Ahafo Region of Ghana. The purpose of the Institute is to build and maintain a stable food system, to take care of the local ecosystems, and to improve the quality of life in the rural areas. The GPN trains students and community in sustainable ecological farming techniques. They support projects throughout Ghana; women groups, micro-finance projects; teach growing moringa; mushroom production; alley cropping, food forests development and Agroforestry.
Permaculture is based on natural sustainable design systems. An agricultural system that uses practices to keep soil fertile, crops and livestock healthy. It encourages protection of the environment and an environmental lifestyle; so as to maintain environmental stability and maintain environmental resources for the future. It rehabilitates eroded and deforested land. The Permaculture Network encourages the practice of permaculture at home. The Permaculture Network's mission is to encourage, educate, and promote the use of permaculture by farmers and people in Ghana, which will contribute to the environmental soundness, and stability of the country's future.
They host international volunteers, interns, and students. The Ghana Permaculture Network and Institute is a member of the Ghana Ecovillage Network. Which is an organization of sustainable development leaders and projects. Paul Yeboah is Vice President of the GEN which works towards promoting Indigenous Initiatives and Sustainability in Ghana. Permaculture is transforming communities in Ghana through education, food production, outreach, skills development, self-sufficiency, and creating small business enterprises.
Background
At the age of 22 Paul Yeboah was concerned with rural and urban poverty. He received an A |
https://en.wikipedia.org/wiki/Developmental%20signaling%20center | A developmental signaling center is defined as a group of cells that release various morphogens which can determine the fates, or destined cell types, of adjacent cells. This process in turn determines what tissues the adjacent cells will form. Throughout the years, various development signaling centers have been discovered.
Spemann-Mangold organizer
In 1924, Hans Spemann and Hilde Mangold discovered a region in the dorsal blastopore lip of an amphibian embryo that induced certain neighboring cells into becoming neural tissue. This Spemann-Mangold organizer was the first time that a developmental organizer region was identified and studied. Since then many analogous organizers have been found in other organisms. The Spemann-Mangold organizer is important to developmental biology because it was the first proof that particular cell populations influenced the differentiation of other cells through signaling molecules.
Nieuwkoop center
The Nieuwkoop center, named after the developmental biologist Pieter Nieuwkoop, is a cluster of dorsal vegetal cells in a blastula which produce both mesoderm-inducing and dorsalizing signals. Signals from the Nieuwkoop center induce the Spemann-Mangold organizer, thus the Nieuwkoop Center is known as the organizer of the organizer. Even with the BCNE center (Blastula chordin and noggin expression center) removed from the blastula, the Nieuwkoop Center is able to induce formation of the Spemann-Mangold organizer. Transplant of the Nieuwkoop Center causes formation of an embryonic axis with an endodermal fate which contains dorsal mesoderm.
Due to difficulty defining definitive Nieuwkoop regions, little is known about the molecular composition of the Nieuwkoop signal. However, cells from the Nieuwkoop Center express potent mesoderm inducers as well as the secreted protein, Cerberus (CER1), which contributes to the formation of the head, heart, and asymmetry of internal organs. Furthermore, a homeobox gene, nieuwkoid, was named after |
https://en.wikipedia.org/wiki/Hedlundia%20hybrida | Hedlundia hybrida, the oakleaf mountain ash, Swedish service-tree or Finnish whitebeam, is a species of whitebeam native to Norway, eastern Sweden, south-western Finland, and locally in Latvia.
Description
Hedlundia hybrida is a medium-sized deciduous tree growing to 10–15 m tall with a stout trunk up to 60 cm in diameter, and grey bark. The crown is columnar or conic in young trees, becoming rounded with age, with branches angled upwards. The leaves are green above, and densely hairy with white hairs beneath. 7–12 cm long and 5–8 cm broad, the leaves are lobed, with six to nine oval lobes on each side of the leaf. These lobes are broadest near the base with the two basal pairs of lobes cut right to the midrib as separate leaflets, rounded at the apex, with finely serrated margins. The autumn colour is dull rusty brown. The flowers are 20 mm in diameter, with five white petals and 20 yellowish-white stamens; they are produced in corymbs 6–11 cm in diameter in late spring. The fruit is a globose pome 12–15 mm in diameter, bright red, maturing in mid-autumn. The fruit is succulent, and eaten by thrushes and waxwings, which disperse the seeds.
Taxonomy
It is a tetraploid species of hybrid origin between the European rowan (Sorbus aucuparia) and the Swedish whitebeam (Scandosorbus intermedia), the latter being a tetraploid triple hybrid between S. aucuparia, the wild service tree (Torminalis glaberrima), and the common whitebeam (Aria edulis) or one of its close relatives. S. intermedia differs from H. hybrida in having the leaves less deeply lobed with no separate leaflets. Closely related Hedlundia meinichii is a triploid or tetraploid species of hybrid origin between H. hybrida and S. aucuparia and differs in having the basal four to six pairs of lobes cut right to the midrib as separate leaflets. All three polyploid species are apomictic species which breed true without pollination.
Cultivation
Hedlundia hybrida is grown as an ornamental tree in northern Europe, |
https://en.wikipedia.org/wiki/Weapon%20target%20assignment%20problem | The weapon target assignment problem (WTA) is a class of combinatorial optimization problems present in the fields of optimization and operations research. It consists of finding an optimal assignment of a set of weapons of various types to a set of targets in order to maximize the total expected damage done to the opponent.
The basic problem is as follows:
There are a number of weapons and a number of targets. The weapons are of type . There are available weapons of type . Similarly, there are targets, each with a value of . Any of the weapons can be assigned to any target. Each weapon type has a certain probability of destroying each target, given by .
Notice that as opposed to the classic assignment problem or the generalized assignment problem, more than one agent (i.e., weapon) can be assigned to each task (i.e., target) and not all targets are required to have weapons assigned. Thus, we see that the WTA allows one to formulate optimal assignment problems wherein tasks require cooperation among agents. Additionally, it provides the ability to model probabilistic completion of tasks in addition to costs.
Both static and dynamic versions of WTA can be considered. In the static case, the weapons are assigned to targets once. The dynamic case involves many rounds of assignment where the state of the system after each exchange of fire (round) is considered in the next round. While the majority of work has been done on the static WTA problem, recently the dynamic WTA problem has received more attention.
In spite of the name, there are nonmilitary applications of the WTA. The main one is to search for a lost object or person by heterogeneous assets such as dogs, aircraft, walkers, etc. The problem is to assign the assets to a partition of the space in which the object is located to minimize the probability of not finding the object. The "value" of each element of the partition is the probability that the object is located there.
Formal mathematical definiti |
https://en.wikipedia.org/wiki/Alspach%27s%20conjecture | Alspach's conjecture is a mathematical theorem that characterizes the disjoint cycle covers of complete graphs with prescribed cycle lengths. It is named after Brian Alspach, who posed it as a research problem in 1981. A proof was published by .
Formulation
In this context, a disjoint cycle cover is a set of simple cycles, no two of which use the same edge, that include all of the edges of a graph. For a disjoint cycle cover to exist, it is necessary for every vertex to have even degree, because the degree of each vertex is two times the number of cycles that include that vertex, an even number. And for the cycles in a disjoint cycle cover to have a given collection of lengths,
it is also necessary for the sum of the given cycle lengths to equal the total number of edges in the given graph. Alspach conjectured that, for complete graphs, these two necessary conditions are also sufficient: if is odd (so that the degrees are even) and a given list of cycle lengths (all at most ) adds to (the number of edges in the complete graph) then the complete graph can always be decomposed into cycles of the given length. It is this statement that Bryant, Horsley, and Pettersson proved.
Generalization to even numbers of vertices
For complete graphs whose number of vertices is even, Alspach conjectured that it is always possible to decompose the graph into a perfect matching and a collection of cycles of prescribed lengths summing to . In this case the matching eliminates the odd degree at each vertex, leaving a subgraph of even degree, and the remaining condition is again that the sum of the cycle lengths equals the number of edges to be covered. This variant of the conjecture was also proven by Bryant, Horsley, and Pettersson.
Related problems
The Oberwolfach problem on decompositions of complete graphs into copies of a given 2-regular graph is related, but neither is a special case of the other.
If is a 2-regular graph, with vertices, formed from a disjoint union of cy |
https://en.wikipedia.org/wiki/Differential%20GPS | Differential Global Positioning Systems (DGPSs) supplement and enhance the positional data available from global navigation satellite systems (GNSSs). A DGPS for GPS can increase accuracy by about a thousandfold, from approximately to .
DGPSs consist of networks of fixed position, ground-based reference stations. Each reference station calculates the difference between its highly accurate known position and its less accurate satellite-derived position. The stations broadcast this data locally—typically using ground-based transmitters of shorter range. Non-fixed (mobile) receivers use it to correct their position by the same amount, thereby improving their accuracy.
The United States Coast Guard (USCG) previously ran DGPS in the United States on longwave radio frequencies between and near major waterways and harbors. It was discontinued in March of 2022. The USCG's DGPS was known as NDGPS (Nationwide DGPS) and was jointly administered by the Coast Guard and the Army Corps of Engineers. It consisted of broadcast sites located throughout the inland and coastal portions of the United States including Alaska, Hawaii and Puerto Rico. The Canadian Coast Guard (CCG) also ran a separate DGPS system, but discontinued its use on December 15, 2022. Other countries have their own DGPS.
A similar system which transmits corrections from orbiting satellites instead of ground-based transmitters is called a Wide-Area DGPS (WADGPS) Satellite Based Augmentation System.
History
When GPS was first being put into service, the US military was concerned about the possibility of enemy forces using the globally available GPS signals to guide their own weapon systems. Originally, the government thought the "coarse acquisition" (C/A) signal would give only about , but with improved receiver designs, the actual accuracy was . Starting in March 1990, to avoid providing such unexpected accuracy, the C/A signal transmitted on the L1 frequency () was deliberately degraded by offsetting its cl |
https://en.wikipedia.org/wiki/List%20of%20model%20car%20brands | This page lists model car brand names past and present. The list is inclusive with slush mold, tinplate, pressed steel, diecast zamac, white metal, plastic and resin models and toys from all over the world. A few are even made of crystal, glass, wood, coal or other materials. Some of the brands here are more toy-like and others are purely for adult collectors. Some are from design model organizations and were never intended for sale. The price of some when new was less than 50 cents, while others cost hundreds or thousands of dollars. Some are kits, some are kits that are specially handbuilt, but many are factory preassembled. Some are promotional in approach while others are solidly set in the retail realm. Some are stationary and do not roll while others roll or have friction or pull-back motors. At a different end of the spectrum, many are remote control. Models of all different sizes are represented, but the typical range is between 1:18 (about 11 inches) to 1:87 (about an inch and a half).
A
AB Minicars – Diecast model cars made in Thailand.
AB-Models – AutoBarn Models
Abrex Kovove Modely Aut – Czech firm, Škoda models in 1:43, 1:24 & some 1:18. Also 1:18 scale Jawa motorcycles.
A.C. Gilbert Company – American manufacturer of 1:32 scale slot cars and sets, 1930s–1960s, though mostly made erector sets.
Academy Plastic Model – Korean plastic model maker, mostly military vehicles. Associated with dinky
Accurate Miniatures – Molded kits made for this company by Monogram. 1:24 scale.
ACME – Hong Kong maker of plastic toys
Action Collectibles – Mainly NASCAR, other stock car diecast, drag racing cars.
Agama Racing – 1:8 radio-controlled buggy specialist
Agat (previously known as Tantal and Mossar) – Soviet/Russian model car brand from Saratov, making 1:43 scale metal models of Soviet and Russian car brands
Airfix – British plastic car and airplane kits. Some built plastic HO military and other toys.
Almost Real
Aluminum Metal Toys (AMT) – American promoti |
https://en.wikipedia.org/wiki/Reverb%20effect | A reverb effect, or reverb, is an audio effect applied to a sound signal to simulate reverberation. It may be created through physical means, such as echo chambers, or electronically through audio signal processing.
The American producer Bill Putnam is credited for the first artistic use of artificial reverb in music, on the 1947 song "Peg o' My Heart" by the Harmonicats. Spring reverb, created with a series of mounted springs, is popular in surf music and dub reggae. Shimmer reverb, which alters the pitch of the reverberated sound, is often used in ambient music. Gated reverb became a staple of 1980s pop music, used by drummers including Phil Collins.
Varieties
Echo chambers
The first reverb effects, introduced in the 1930s, were created by playing recordings through loudspeakers in reverberating spaces and recording the sound. The American producer Bill Putnam is credited for the first artistic use of artificial reverb in music, on the 1947 song "Peg o' My Heart" by the Harmonicats. Putnam placed a microphone and loudspeaker in the studio bathroom to create an echo chamber, adding an "eerie dimension".
Plate reverb
A plate reverb system uses an electromechanical transducer, similar to the driver in a loudspeaker, to create vibrations in a large plate of sheet metal. The plate's motion is picked up by one or more contact microphones whose output is an audio signal which may be added to the original "dry" signal. Plate reverb was introduced in the late 1950s by Elektromesstechnik with the EMT 140.
Spring reverb
Spring reverbs, introduced by Bell Labs, use a set of springs mounted inside a box. They work similarly to plate reverb, with a transducer and pickup placed at either end of the spring. They were popular in the 1960s, and were first used by the Hammond company to add reverb to Hammond organs. They became popular with guitarists, including surf musicians such as Dick Dale, as they could easily be built into guitar amplifiers. They were also used by |
https://en.wikipedia.org/wiki/Comparison%20matrix | In linear algebra, let be a complex matrix. The comparison matrix of complex matrix A is defined as
See also
Hurwitz matrix
P-matrix
Perron–Frobenius theorem
Z-matrix
L-matrix
M-matrix
H-matrix (iterative method) |
https://en.wikipedia.org/wiki/Percutaneous%20epididymal%20sperm%20aspiration | Percutaneous epididymal sperm aspiration (PESA) is a technique used to determine sperm counts in the event of a possible blockage of the vas deferens. It is an alternative to microepidydimal sperm aspiration (MESA), and aims to address the technical difficulty and cost of MESA. A small needle is inserted through the skin of the scrotum to collect sperm from the epididymis, where sperm are usually stored after production in the testes. It can also be used to extract sperm for intracytoplasmic sperm injection (ICSI). |
https://en.wikipedia.org/wiki/Progressive%20function | In mathematics, a progressive function ƒ ∈ L2(R) is a function whose Fourier transform is supported by positive frequencies only:
It is called super regressive if and only if the time reversed function f(−t) is progressive, or equivalently, if
The complex conjugate of a progressive function is regressive, and vice versa.
The space of progressive functions is sometimes denoted , which is known as the Hardy space of the upper half-plane. This is because a progressive function has the Fourier inversion formula
and hence extends to a holomorphic function on the upper half-plane
by the formula
Conversely, every holomorphic function on the upper half-plane which is uniformly square-integrable on every horizontal line
will arise in this manner.
Regressive functions are similarly associated with the Hardy space on the lower half-plane .
Hardy spaces
Types of functions |
https://en.wikipedia.org/wiki/Median%20filter | The median filter is a non-linear digital filtering technique, often used to remove noise from an image or signal. Such noise reduction is a typical pre-processing step to improve the results of later processing (for example, edge detection on an image). Median filtering is very widely used in digital image processing because, under certain conditions, it preserves edges while removing noise (but see the discussion below), also having applications in signal processing.
Algorithm description
The main idea of the median filter is to run through the signal entry by entry, replacing each entry with the median of neighboring entries. The pattern of neighbors is called the "window", which slides, entry by entry, over the entire signal. For one-dimensional signals, the most obvious window is just the first few preceding and following entries, whereas for two-dimensional (or higher-dimensional) data the window must include all entries within a given radius or ellipsoidal region (i.e. the median filter is not a separable filter).
Worked one-dimensional example
To demonstrate, using a window size of three with one entry immediately preceding and following each entry, a median filter will be applied to the following simple one-dimensional signal:
x = (2, 3, 80, 6, 2, 3).
So, the median filtered output signal y will be:
y1 = med(2, 3, 80) = 3, (already 2, 3, and 80 are in the increasing order so no need to arrange them)
y2 = med(3, 80, 6) = med(3, 6, 80) = 6, (3, 80, and 6 are rearranged to find the median)
y3 = med(80, 6, 2) = med(2, 6, 80) = 6,
y4 = med(6, 2, 3) = med(2, 3, 6) = 3,
i.e. y = (3, 6, 6, 3).
Boundary issues
When implementing a median filter, the boundaries of the signal must be handled with special care, as there are not enough entries to fill an entire window. There are several schemes that have different properties that might be preferred in particular circumstances:
When calculating the median of a value near the boundary, missing values are f |
https://en.wikipedia.org/wiki/Pipeline%20%28Unix%29 | In Unix-like computer operating systems, a pipeline is a mechanism for inter-process communication using message passing. A pipeline is a set of processes chained together by their standard streams, so that the output text of each process (stdout) is passed directly as input (stdin) to the next one. The second process is started as the first process is still executing, and they are executed concurrently.
The concept of pipelines was championed by Douglas McIlroy at Unix's ancestral home of Bell Labs, during the development of Unix, shaping its toolbox philosophy. It is named by analogy to a physical pipeline. A key feature of these pipelines is their "hiding of internals" (Ritchie & Thompson, 1974). This in turn allows for more clarity and simplicity in the system.
This article is about anonymous pipes, where data written by one process is buffered by the operating system until it is read by the next process, and this uni-directional channel disappears when the processes are completed. This differs from named pipes, where messages are passed to or from a pipe that is named by making it a file, and remains after the processes are completed. The standard shell syntax for anonymous pipes is to list multiple commands, separated by vertical bars ("pipes" in common Unix verbiage):
command1 | command2 | command3
For example, to list files in the current directory (), retain only the lines of output containing the string (), and view the result in a scrolling page (), a user types the following into the command line of a terminal:
ls -l | grep key | less
The command ls -l is executed as a process, the output (stdout) of which is piped to the input (stdin) of the process for grep key; and likewise for the process for less. Each process takes input from the previous process and produces output for the next process via standard streams. Each | tells the shell to connect the standard output of the command on the left to the standard input of the command on the right by |
https://en.wikipedia.org/wiki/Vampirella | Vampirella () is a fictional vampire superheroine created by Forrest J Ackerman and comic book artist Trina Robbins in Warren Publishing's black-and-white horror comics magazine Vampirella #1 (Sept. 1969), a sister publication of Creepy and Eerie.
Writer-editor Archie Goodwin later developed the character from horror-story hostesses, in which capacity she remained through issue #8 (Nov. 1970), to a horror-drama leading character. The magazine was published continuously until 1983, when Warren Publishing ceased operations and its assets were bought by Harris Publications. Vampirella comics, both new and reprints, have continued through various publishers into the 21st century.
Publication history
Warren Publishing
Vampirella initially appeared in Warren Publishing's black-and-white horror-comics magazine Vampirella #1 (Sept. 1969), running to issue #112 (March 1983), plus a 1972 annual reprinting stories from the series, and a 1977 special with color reprints of José González stories. The title was a sister magazine of Warren's horror anthologies Creepy and Eerie. Like those magazines' respective mascots, Uncle Creepy and Cousin Eerie, Vampirella hosted horror stories, though unlike them, she would also star in her own story, which would headline each issue. Vampirella was initially edited by Bill Parente. It would later be edited by Archie Goodwin (issues #7–12, 34–35), Billy Graham (#13–16), Bill DuBay (#21–50, 87–95, 101–102) and Louise Jones (#51–86).
According to comics historian Richard J. Arndt, "Forrest Ackerman created, or at least had a strong hand in creating, Vampirella and he clearly had a major influence in shaping the lighthearted bad-girl story style of this issue as well." Her costume and hair style were designed by comics artist Trina Robbins. The character's first story artist was Tom Sutton. Artist Frank Frazetta's first-issue cover was a substitute for the original cover by European artist Aslan.
José González became the character's primary |
https://en.wikipedia.org/wiki/NetTop | NetTop is an NSA project to run Multiple Single-Level systems with a Security-Enhanced Linux host running VMware with Windows as a guest operating system.
NetTop has .
External links
NSA web page on NetTop
VMware PR page on NetTop
HP NetTop web page
TCS Trusted Workstation based on NetTop
Linux security software
National Security Agency operations |
https://en.wikipedia.org/wiki/Nancy%20Blachman | Nancy Blachman (born 1956 in Palo Alto, CA) is an American educator, supporter of recreational mathematics and mathematical outreach, software book author, and supporter of indie documentary films. In 2007, she founded the Julia Robinson Mathematics Festival (JRMF), which has grown into a successful math enrichment enterprise for teenagers in the USA and beyond. She is a former chair of Gathering 4 Gardner and is still an active board member. She is currently Chair of the Advisory Board of Berkeley’s Industrial Engineering and Operations Research Department (IEOR).
Education and career
Nancy Blachman was born in 1956 in Palo Alto, California, her father Nelson being an electrical engineer. The family spent some time living in Spain in the 1960s, and Nancy's interest in mathematics began during high school back in Palo Alto when she took a course based on George Polya's
Mathematics and Plausible Reasoning. She was also inspired by the mathematics contest produced by Saint Mary's College of California then popular with secondary schools throughout the San Francisco Bay Area.
Blachman did undergraduate work at University of California, San Diego (1974 to 1976), got honours B.Sc. in applied mathematics from the University of Birmingham in the UK (1978), an M.S. in operations research from University of California, Berkeley (1979) and an M.S. in computer science at Stanford University (1988).
She taught a course in problem solving with Mathematica at Stanford from 1990 to 1997.
In 2004 she created Google Guide, an online interactive tutorial and reference about the capabilities of Google.
In 2005 while attending an education forum that promoted STEM [Science, Technology, Engineering, and Math] she remembered how the Saint Mary's College Mathematics Contest had inspired her as a student. Working with Joshua Zucker and Jim Sotiros she decided to revive the structure and spirit of this long defunct competition. This led to the founding of the Julia Robinson Mathematic |
https://en.wikipedia.org/wiki/Tepidisphaera | Tepidisphaera is a genus of bacteria from the family of Planctomycetaceae with one known species (Tepidisphaera mucosa). Tepidisphaera mucosa has been isolated from a hot spring from the Lake Baikal in Kamchatka in Russia. |
https://en.wikipedia.org/wiki/Fast%20Green%20FCF | Fast Green FCF, also called Food green 3, FD&C Green No. 3, Green 1724, Solid Green FCF, and C.I. 42053, is a turquoise triarylmethane food dye. Its E number is E143.
Fast Green FCF is recommended as a replacement of Light Green SF yellowish in Masson's trichrome, as its color is more brilliant and less likely to fade. It is used as a quantitative stain for histones at alkaline pH after acid extraction of DNA. It is also used as a protein stain in electrophoresis. Its absorption maximum is at 625 nm.
Fast Green FCF is poorly absorbed by the intestines. Its use as a food dye is prohibited in the European Union and some other countries. It can be used for tinned green peas and other vegetables, jellies, sauces, fish, desserts, and dry bakery mixes at level of up to 100 mg/kg. In the United States, Fast Green FCF is the least used of the seven main FDA approved dyes.
Toxicology
A reevaluation of Fast Green FCF published by the World Health Organization in 2017 concluded that it has low toxicity and is not carcinogenic or genotoxic, and that there were no health concerns with consumption of Fast Green FCF at the previously established allowable daily intake (which itself is much higher than estimates of actual dietary exposure to Fast Green FCF).
Notes
Biochemistry detection methods
Triarylmethane dyes
Staining dyes
Food colorings
Anilines
Phenols
Benzenesulfonates |
https://en.wikipedia.org/wiki/Hill%20climbing | In numerical analysis, hill climbing is a mathematical optimization technique which belongs to the family of local search. It is an iterative algorithm that starts with an arbitrary solution to a problem, then attempts to find a better solution by making an incremental change to the solution. If the change produces a better solution, another incremental change is made to the new solution, and so on until no further improvements can be found.
For example, hill climbing can be applied to the travelling salesman problem. It is easy to find an initial solution that visits all the cities but will likely be very poor compared to the optimal solution. The algorithm starts with such a solution and makes small improvements to it, such as switching the order in which two cities are visited. Eventually, a much shorter route is likely to be obtained.
Hill climbing finds optimal solutions for convex problems – for other problems it will find only local optima (solutions that cannot be improved upon by any neighboring configurations), which are not necessarily the best possible solution (the global optimum) out of all possible solutions (the search space). Examples of algorithms that solve convex problems by hill-climbing include the simplex algorithm for linear programming and binary search. To attempt to avoid getting stuck in local optima, one could use restarts (i.e. repeated local search), or more complex schemes based on iterations (like iterated local search), or on memory (like reactive search optimization and tabu search), or on memory-less stochastic modifications (like simulated annealing).
The relative simplicity of the algorithm makes it a popular first choice amongst optimizing algorithms. It is used widely in artificial intelligence, for reaching a goal state from a starting node. Different choices for next nodes and starting nodes are used in related algorithms. Although more advanced algorithms such as simulated annealing or tabu search may give better results |
https://en.wikipedia.org/wiki/Paul%20Milgrom | Paul Robert Milgrom (born April 20, 1948) is an American economist. He is the Shirley and Leonard Ely Professor of Humanities and Sciences at the Stanford University School of Humanities and Sciences, a position he has held since 1987. He is a professor in the Stanford School of Engineering as well and a Senior Fellow at the Stanford Institute for Economic Research. Milgrom is an expert in game theory, specifically auction theory and pricing strategies. He is the winner of the 2020 Nobel Memorial Prize in Economic Sciences, together with Robert B. Wilson, "for improvements to auction theory and inventions of new auction formats".
He is the co-creator of the no-trade theorem with Nancy Stokey. He is the co-founder of several companies, the most recent of which, Auctionomics, provides software and services for commercial auctions and exchanges.
Milgrom and his thesis advisor Wilson designed the auction protocol the FCC uses to determine which phone company gets what cellular frequencies. Milgrom also led the team that designed the broadcast incentive auction between 2016 and 2017, which was a two-sided auction to reallocate radio frequencies from TV broadcast to wireless broadband uses.
Early life and education
Paul Milgrom was born in Detroit, Michigan, April 20, 1948, the second of four sons to Jewish parents Abraham Isaac Milgrom and Anne Lillian Finkelstein. His family moved to Oak Park, Michigan, and Milgrom attended the Dewey Elementary School and then Oak Park High School.
Milgrom graduated from the University of Michigan in 1970 with an AB in mathematics. He worked as an actuary for several years in San Francisco at the Metropolitan Insurance Company and then at the Nelson and Warren consultancy in Columbus, Ohio. Milgrom became a Fellow of the Society of Actuaries in 1974. In 1975, Milgrom enrolled for graduate studies at Stanford University and earned an MS in statistics in 1978 and a PhD in business in 1979.
Academic career
Milgrom assumed a teaching |
https://en.wikipedia.org/wiki/Builder%27s%20Old%20Measurement | Builder's Old Measurement (BOM, bm, OM, and o.m.) is the method used in England from approximately 1650 to 1849 for calculating the cargo capacity of a ship. It is a volumetric measurement of cubic capacity. It estimated the tonnage of a ship based on length and maximum beam. It is expressed in "tons burden" (, ), and abbreviated "tons bm".
The formula is:
where:
Length is the length, in feet, from the stem to the sternpost;
Beam is the maximum beam, in feet.
The Builder's Old Measurement formula remained in effect until the advent of steam propulsion. Steamships required a different method of estimating tonnage, because the ratio of length to beam was larger and a significant volume of internal space was used for boilers and machinery. In 1849, the Moorsom System was created in the United Kingdom. The Moorsom system calculates the cargo-carrying capacity in cubic feet, another method of volumetric measurement. The capacity in cubic feet is then divided by 100 cubic feet of capacity per gross ton, resulting in a tonnage expressed in tons.
History and derivation
King Edward I levied the first tax on the hire of ships in England in 1303 based on tons burthen. Later, King Edward III levied a tax of 3 shillings on each "tun" of imported wine, equivalent to about £126.30 in 2021. At that time a "tun" was a wine container of 252 wine gallons, approx weighing about , a weight known today as a long ton or imperial ton. In order to estimate the capacity of a ship in terms of 'tun' for tax purposes, an early formula used in England was:
where:
Length is the length (undefined), in feet
Beam is the beam, in feet.
Depth is the depth of the hold, in feet below the main deck.
The numerator yields the ship's volume expressed in cubic feet.
If a "tun" is deemed to be equivalent to 100 cubic feet, then the tonnage is simply the number of such 100 cubic feet 'tun' units of volume.
100 the divisor is unitless, so tonnage would be expressed in 'ft3 of tun'.
In 1678 |
https://en.wikipedia.org/wiki/Hidden%20node%20problem | In wireless networking, the hidden node problem or hidden terminal problem occurs when a node can communicate with a wireless access point (AP), but cannot directly communicate with other nodes that are communicating with that AP. This leads to difficulties in medium access control sublayer since multiple nodes can send data packets to the AP simultaneously, which creates interference at the AP resulting in no packet getting through.
Although some loss of packets is normal in wireless networking, and the higher layers will resend them, if one of the nodes is transferring a lot of large packets over a long period, the other node may get very little goodput.
Practical protocol solutions exist to the hidden node problem. For example, Request To Send/Clear To Send (RTS/CTS) mechanisms where nodes send short packets to request permission of the access point to send longer data packets. Because responses from the AP are seen by all the nodes, the nodes can synchronize their transmissions to not interfere. However, the mechanism introduces latency, and the overhead can often be greater than the cost, particularly for short data packets.
Background
Hidden nodes in a wireless network are nodes that are out of range of other nodes or a collection of nodes. Consider a physical star topology with an access point with many nodes surrounding it in a circular fashion: each node is within communication range of the AP, but the nodes cannot communicate with each other.
For example, in a wireless network, it is likely that the node at the far edge of the access point's range, which is known as A, can see the access point, but it is unlikely that the same node can communicate with a node on the opposite end of the access point's range, C. These nodes are known as hidden.
Another example would be where A and C are either side of an obstacle that reflects or strongly absorbs radio waves, but nevertheless they can both still see the same AP.
The problem is when nodes A and C start |
https://en.wikipedia.org/wiki/Community%20greens | Community Greens, sometimes referred to as backyard commons, urban commons, or pocket neighborhoods, are shared open green spaces on the inside of city blocks, created either when residents merge backyard space or reclaim underutilized urban land such as vacant lots and alleyways. These shared spaces are communally used and managed only by the residents whose homes abut them. They are not a public park, a private backyard, or a community garden; however, they can function as all three.
Community Greens
Community Greens is an organization concerned with the development of shared green spaces in residential neighborhoods in American cities. These green spaces are community greens. The Community Greens movement believes that such an approach presents the best opportunity to add usable green space to American cities, by converting under utilized backyards and dysfunctional alleys into functional and beautiful shared green spaces that are owned, managed, and enjoyed by the people who live around them.
This has led communities in numerous American cities, including Boston, Sacramento, Baltimore, New York, and San Francisco, taking down their backyard fences, to create backyard commons.
Community Greens are multi-functional spaces for gardening, recreation, and leisure which are designed to provide social, economic, and environmental benefits to urban residents. The creation of backyard commons can lead to an increased interaction with neighbors throughout the planning and implementation process, which may result in a stronger overall sense of community. Other possible social benefits that are claimed include decreased crime, from having more eyes on the street, and safe places where children can play and adults relax. Community Greens, like other types of urban green spaces, can significantly improve the ecological functioning of urban habitats. Vegetation and permeable pavement can slow storm water runoff and increase groundwater, which in turn can reduce pollutant |
https://en.wikipedia.org/wiki/Q15X25 | Q15X25 is a communications protocol for sending data over a radio link. It was designed by amateur radio operator Pawel Jalocha, SP9VRC, to be an open communications standard. Like all amateur radio communications modes, this protocol uses open transmissions which can be received and decoded by anyone with similar equipment. Q15X25 is a form of packet radio. It can be used to interconnect local VHF AX.25 packet networks over transcontinental distances. Anyone can design or adapt the open-source software to develop their own Q15X25 system.
Q15X25 is a digital signal processor-intensive mode designed to pass AX.25 packets on HF with speed and reliability much greater than traditional HF ARQ modems. It uses 15 QPSK modulated carriers separated by 125 Hertz, each modulated at 83.333 baud. Q15X25 uses forward error correction (FEC), and like MT63, uses time- and frequency-interleaving in order to avoid most error sources. The raw transmission data rate is typically 2500 bit/s.
Typically the DSP based receiver and transmitter modulator or codec is implemented as PC software that uses a sound card to connect directly to an SSB transceiver. Linux implementations are usually called "newpsk" or "newqpsk". MixW, a multipurpose communications control and digital modes package on Windows can implement Kiss and/or "TCP/IP over X.25" on either traditional 300 baud, 1200 baud and 2400 baud FSK packet "modems" implemented as DSP via sound card or over Q15X25. The "FlexNet" Windows packet software also has a newqpsk / Q15X25 option.
As with any amateur radio transmission, anyone can listen/decode Q15X25 transmissions, but an amateur radio operation license is required for transmission.
Frequencies (all USB) in use are (MixW center about 1350 Hz higher):
See also
Radioteletype
Shortwave
External links
ARRL description of Q15X25
MixW
Quantized radio modulation modes
Packet radio |
https://en.wikipedia.org/wiki/San%20Luis%20National%20Wildlife%20Refuge%20Complex | The San Luis National Wildlife Refuge Complex is located in the northern San Joaquin Valley, within Merced County and Stanislaus County of California. The complex, with four federal National Wildlife Refuges, is managed by the U.S Fish & Wildlife Service.
Introduction
The complex is composed of the San Luis National Wildlife Refuge, Merced National Wildlife Refuge, San Joaquin River National Wildlife Refuge, and the Grasslands Wildlife Management Area. The complex consists of nearly of wetlands, grasslands, and riparian habitats, as well as over of conservation easements on private lands for the protection and benefit of wildlife. The complex is headquartered in Los Banos, California and uses the Sierra National Forest Emergency Communication Center located in Fresno, California for emergency dispatch.
The complex is located within the Pacific Flyway, a major route for migrating birds, including waterfowl. The extensive wetlands of the complex and surrounding lands provide habitat for up to a million waterfowl that arrive here each winter. Of the 30 species of waterfowl using the complex, the most common include Ross's geese, Aleutian cackling geese, snow geese, green-winged teal, mallards, northern pintails, gadwalls, American wigeons, northern shovelers, and greater white-fronted geese.
The complex is an integral part of a mosaic of federal, state, and private lands in Merced and Stanislaus Counties that together constitute the largest contiguous freshwater wetlands remaining in California. This area has been recognized as a Ramsar Wetland of International Importance, an Audubon Important Bird Area, and as a Western Hemisphere Shorebird Reserve Network site.
Wildlife refuge units
San Luis National Wildlife Refuge
The San Luis National Wildlife Refuge encompasses over of wetlands, riparian forests, native grasslands and vernal pools. A thriving population of tule elk is showcased by one of three auto tour routes. The refuge is host to significant assem |
https://en.wikipedia.org/wiki/Game%20accessibility | Within the field of human–computer interaction, accessibility of video games is considered a sub-field of computer accessibility, which studies how software and computers can be made accessible to users with various types of impairments. It can also include tabletop RPGs, board games, and related products.
In spring 2020, the COVID-19 pandemic caused a massive boom of the video game industry. With an increasing number of people interested in playing video games and with video games increasingly being used for other purposes than entertainment, such as education, rehabilitation or health, game accessibility has become an emerging field of research, especially as players with disabilities could benefit from the opportunities video games offer the most. A 2010 study estimated that 2% of the U.S. population is unable to play a game at all because of an impairment and 9% can play games but suffers from a reduced gaming experience. A study conducted by casual games studio PopCap games found that an estimated one in five casual video gamers have a physical, mental or developmental disability. As games are increasingly used as education tools, there may be a legal obligation to make them accessible, as Section 508 of the Rehabilitation Act mandates that schools and universities that rely on federal funding must make their electronic and information technologies accessible. , the U.S. Federal Communications Commission (FCC) requires in-game communication between players on consoles to be accessible to players with sensory disabilities. In 2021, video game developers attempted to improve accessibility through every possible avenue. This includes reducing difficulty and enabling auto fire.
Outside of being used as education or rehabilitation tools video games are used as identification aspects leading disabled people to work much harder to attach additional meaning when gaming. This transforms the very nature of playing video games into a fight against a digitally divided c |
https://en.wikipedia.org/wiki/Balanitis | Balanitis is inflammation of the glans penis. When the foreskin is also affected, the proper term is balanoposthitis. Balanitis on boys still in diapers must be distinguished from redness caused by ammoniacal dermatitis. The word balanitis is from the Greek βάλανος , literally meaning 'acorn', used because of the similarity in shape to the glans penis.
Signs and symptoms
Small red erosions on the glans (first sign)
Redness of the foreskin
Redness of the penis
Other rashes on the head of the penis
Foul smelling discharge
Painful foreskin and penis
Complications
Recurrent bouts of balanitis may cause scarring of the preputial orifice; the reduced elasticity may lead to pathologic phimosis. Further complications may include:
Stricture of urinary meatus
Phimosis
Paraphimosis
Cause
Inflammation has many possible causes, including irritation by environmental substances, certain medications, physical trauma, and infection such as bacterial, viral, or fungal. Some of these infections are sexually transmitted diseases.
It is less common among people who are circumcised, as in many cases, a dysfunction of the foreskin is a causal or contributing factor. Both not enough cleaning and too much cleaning can cause problems.
Diagnosis
Diagnosis may include careful identification of the cause with the aid of a good patient history, swabs and cultures, and pathological examination of a biopsy.
Types
Zoon's balanitis, also known as Balanitis Circumscripta Plasmacellularis or plasma cell balanitis (PCB), is an idiopathic, rare, benign penile dermatosis for which circumcision is often the preferred treatment. Zoon's balanitis has been successfully treated with the carbon dioxide laser; and more recently, Albertini and colleagues report the avoidance of circumcision and successful treatment of Zoon's balanitis with an Er:YAG laser. Another study, by Retamar and colleagues, found that 40 percent of those treated with CO2 laser relapsed.
Circinate balanitis, also known |
https://en.wikipedia.org/wiki/The%20Gap%20%28book%29 | The Gap is a 2013 nonfiction book by Thomas Suddendorf that discusses what cognitive qualities separate humans from other animals, and how they evolved.
The Gap: The Science of What Separates Us From Other Animals. Basic Books: New York
Reviews
Anil Ananthaswamy (27 January 2014). What separates us from other animals? New Scientist Retrieved October 5, 2014, from https://www.newscientist.com/article/mg22129531.100-what-separates-us-from-other-animals.html
Robyn Williams (March 2014). The science of what separates us from other animals. Australian Book Review. Retrieved on October 5, 2014, from http://www.australianbookreview.com.au/abr-online/current-issue/113-march-2014-no-359/1859-the-gap
Joseph Maldonado (2013). The Gap: The Science of What Separates Us from Other Animals. Psych Central. Retrieved on October 5, 2014, from http://psychcentral.com/lib/the-gap-the-science-of-what-separates-us-from-other-animals/00018372
Steven Mithen (3 April 2013). Most of Us Are Part Neanderthal. The New York Review of Books. Retrieved on October 5, 2014, from http://www.nybooks.com/articles/archives/2014/apr/03/most-us-are-part-neanderthal/?page=2
Wray Herbert (10 February 2014). Social Animals - Pondering the limits of anthropomorphism. The Weekly Standard Vol. 19, No. 21. Retrieved on October 5, 2014, from http://www.weeklystandard.com/articles/social-animals_775990.html
David Barash (15 November 2013). Book Review: 'The Gap' by Thomas Suddendorf - What makes humans unique—tools? Language? Cooking?. The Wall Street Journal. Retrieved on October 5, 2014, from https://www.wsj.com/articles/SB10001424052702304527504579169670682265630
Nina Bai (17 October 2013). MIND Reviews: The Gap. Scientific American Mind volume 24 issue 5. Retrieved on October 5, 2014, from http://www.scientificamerican.com/article/mind-reviews-the-gap/
Eric Michael Johnson (20 March 2014). The Gap: The Science of What Separates Us From Other Animals, by Thomas Suddendorf. The Times Higher Education. |
https://en.wikipedia.org/wiki/Primitive%20ideal | In mathematics, specifically ring theory, a left primitive ideal is the annihilator of a (nonzero) simple left module. A right primitive ideal is defined similarly. Left and right primitive ideals are always two-sided ideals.
Primitive ideals are prime. The quotient of a ring by a left primitive ideal is a left primitive ring. For commutative rings the primitive ideals are maximal, and so commutative primitive rings are all fields.
Primitive spectrum
The primitive spectrum of a ring is a non-commutative analog of the prime spectrum of a commutative ring.
Let A be a ring and the set of all primitive ideals of A. Then there is a topology on , called the Jacobson topology, defined so that the closure of a subset T is the set of primitive ideals of A containing the intersection of elements of T.
Now, suppose A is an associative algebra over a field. Then, by definition, a primitive ideal is the kernel of an irreducible representation of A and thus there is a surjection
Example: the spectrum of a unital C*-algebra.
See also
Dixmier mapping
Notes |
https://en.wikipedia.org/wiki/Harvard%20Mark%20I | The Harvard Mark I, or IBM Automatic Sequence Controlled Calculator (ASCC), was one of the earliest general-purpose electromechanical computers used in the war effort during the last part of World War II.
One of the first programs to run on the Mark I was initiated on 29 March 1944 by John von Neumann. At that time, von Neumann was working on the Manhattan Project, and needed to determine whether implosion was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables, which had been the initial goal of British inventor Charles Babbage for his "analytical engine" in 1837.
The Mark I was disassembled in 1959; part of it was given to IBM, part went to the Smithsonian Institution, and part entered the Harvard Collection of Historical Scientific Instruments. For decades, Harvard's portion was on display in the lobby of the Aiken Computation Lab. About 1997, it was moved to the Harvard Science Center. In 2021, it was moved again, to the lobby of Harvard's new Science and Engineering Complex in Allston, Massachusetts.
Origins
The original concept was presented to IBM by Howard Aiken in November 1937. After a feasibility study by IBM engineers, the company chairman Thomas Watson Sr. personally approved the project and its funding in February 1939.
Howard Aiken had started to look for a company to design and build his calculator in early 1937. After two rejections, he was shown a demonstration set that Charles Babbage’s son had given to Harvard University 70 years earlier. This led him to study Babbage and to add references to the Analytical Engine to his proposal; the resulting machine "brought Babbage’s principles of the Analytical Engine almost to full realization, while adding important new features."
The ASCC was developed and built by IBM at their Endicott plant and shipped to Harvard in February 1944. It began computations for the US Navy Bureau of Ships in May and was officially prese |
https://en.wikipedia.org/wiki/Distributed%20System%20Security%20Architecture | Distributed System Security Architecture or (DSSA) is a computer security architecture that provides a suite of functions including login, authentication, and access control in a distributed system. To differ from other similar architectures, the DSSA architecture offers the ability to access all these functions without the trusted server (known as a certificate authority) being active.
In DSSA, security objects are handled by owners and access is controlled by the central, universally trusted, certificate authority.
DSSA/SPX
DSSA/SPX is the authentication protocol of DSSA. The CDC is a certificate granting server while the certificate is a ticket signed by CA which contains the public key of the party being certified. Since the CDC is merely distributing previously signed certificates, it is not necessary for it to be trusted.
External links
Tromsø University
Gasser (1989)
Cryptographic protocols |
https://en.wikipedia.org/wiki/Lymphovascular%20invasion | Lymphovascular invasion (LVI or lymphovascular space invasion) is the invasion of a cancer to the blood vessels and/or lymphatics.
Terminology
Lymph: A clear or white fluid that travels through vessels, moves within tissues and work to keep all the parts of the body clean.
Vascular: The body's network of blood vessels.
When cancer spreads to lymph and vascular system, it is thus termed as Lymphovascular Invasion.
Pathology
Lymphovascular invasion, especially in carcinomas, usually precedes spread to the lymph nodes that drain the tissue in which the tumour arose. Conversely, cancers with lymph node spread (known as a lymph node metastases), usually have lymphovascular invasion. Lymph node metastases usually precede secondary tumours, i.e. distant metastases.
The absence of LVI in the context of proven lymph node metastasis is usually thought to be due to sampling error.
Prognostic significance
The predictive value and prevalence of lymphovascular invasion is strongly dependent on the type of cancer. In other words, LVI in one type of cancer may be much less important than LVI in another type of cancer.
Generally speaking, it is associated with lymph node metastases which themselves are predictive of a poorer prognosis. In the context of (histologically) proven lymph node metastases, LVI may have less prognostic significance or no prognostic significance.
Breast cancer
Whether LVI is a significant prognostic factor in breast cancer is widely debated, and there is no clear consensus.
Urothelial carcinoma
In urothelial carcinoma, LVI is an independent predictor of a poorer prognosis that has more predictive power than tumour stage.
Colorectal cancer
In sporadic colorectal carcinoma, LVI of a poorer prognosis.
See also
Perineural invasion
Malignancy |
https://en.wikipedia.org/wiki/Brahmagupta%27s%20problem | This problem was given in India by the mathematician Brahmagupta in 628 AD in his treatise Brahma Sputa Siddhanta:
Solve the Pell's equation
for integers .
Brahmagupta gave the smallest solution as
.
See also
Brahmagupta
Indian mathematics
List of Indian mathematicians
Pell's equation
Indeterminate equation
Diophantine equation
External links
Brahmagupta
Diophantine equations |
https://en.wikipedia.org/wiki/Center%20channel | Center channel refers to an audio channel common to many surround sound formats. It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program. The speaker(s) connected to the center channel are placed in the center of and behind the perforated projection screen, to give the effect that sounds from the center channel are coming from the screen. In many home surround sound units, the center channel is positioned above or below the video screen.
In the post-production process of filmmaking and video production sound editing, dialogue can be mapped to other speakers when story action and direction require it, such as when the person talking is off-screen, but it is rare that there is vocal content that is completely absent from the center channel.
In material without accompanying visuals (e.g. music), the center channel simply reproduces sound intended to come from immediately in front of the listener, which usually includes the lead vocals, which are rarely panned hard left or right.
The center channel also anchors the sound field, eliminating phantom images such as those that plagued quadraphonic sound if the speakers were not precisely placed.
The center channel eliminates the need of creating a phantom center with left and right stereo speakers. The center channel provides image stabling effects and is considered the most important channel for film production.
History
The need for a center speaker to locate screen-centered sounds has been recognised since the Bell labs experiments in stereo sound from the 1930s, and multi-channel cinema sound systems, starting with the first commercial stereophonic film (Fantasia-1941) have always included one. Post-war stereo sound in theaters initially came from separate magnetic film reproducers synchronised to the picture, but in the 1950s systems using magnetic stripes on the film itself came into use. Cinemascope used four such tracks (left, center, right and surrou |
https://en.wikipedia.org/wiki/Modulin | Modulin may refer to:
Modulen, The brand of dietary supplement by Nestlé designed for persons with Crohn's disease
Phenol-soluble modulin, a family of protein toxins
Toll-like receptor and TLR 2, proteins of which some were previously classified as "modulins"
A musical instrument that is a monophonic analogue homebuilt theremin/violin-esque synthesizer, invented by the band Wintergatan
Proteins |
https://en.wikipedia.org/wiki/Major%20urinary%20proteins | Major urinary proteins (Mups), also known as α2u-globulins, are a subfamily of proteins found in abundance in the urine and other secretions of many animals. Mups provide a small range of identifying information about the donor animal, when detected by the vomeronasal organ of the receiving animal. They belong to a larger family of proteins known as lipocalins. Mups are encoded by a cluster of genes, located adjacent to each other on a single stretch of DNA, that varies greatly in number between species: from at least 21 functional genes in mice to none in humans. Mup proteins form a characteristic glove shape, encompassing a ligand-binding pocket that accommodates specific small organic chemicals.
Urinary proteins were first reported in rodents in 1932, during studies by Thomas Addis into the cause of proteinuria. They are potent human allergens and are largely responsible for a number of animal allergies, including to cats, horses and rodents. Their endogenous function within an animal is unknown but may involve regulating energy expenditure. However, as secreted proteins they play multiple roles in chemical communication between animals, functioning as pheromone transporters and stabilizers in rodents and pigs. Mups can also act as protein pheromones themselves. They have been demonstrated to promote aggression in male mice, and one specific Mup protein found in male mouse urine is sexually attractive to female mice. Mups can also function as signals between different species: mice display an instinctive fear response on the detection of Mups derived from predators such as cats and rats.
Discovery
Humans in good health excrete urine that is largely free of protein. Therefore, since 1827 physicians and scientists have been interested in proteinuria, the excess of protein in human urine, as an indicator of kidney disease. To better understand the etiology of proteinuria, some scientists attempted to study the phenomenon in laboratory animals. Between 1932 and 19 |
https://en.wikipedia.org/wiki/Talimogene%20laherparepvec | Talimogene laherparepvec, sold under the brand name Imlygic, is a biopharmaceutical medication used to treat melanoma that cannot be operated on; it is injected directly into a subset of lesions which generates a systemic immune response against the recipient's cancer. The final four year analysis from the pivotal phase 3 study upon which TVEC was approved by the FDA showed a 31.5% response rate with a 16.9% complete response (CR) rate. There was also a substantial and statistically significant survival benefit in patients with earlier metastatic disease (stages IIIb-IVM1a) and in patients who hadn't received prior systemic treatment for melanoma. The earlier stage group had a reduction in the risk of death of approximately 50% with one in four patients appearing to have met, or be close to be reaching, the medical definition of cure. Real world use of talimogene laherparepvec have shown response rates of up to 88.5% with CR rates of up to 61.5%.
Around half of people treated with talimogene laherparepvec in clinical trials experienced fatigue and chills; around 40% had fever, around 35% had nausea, and around 30% had flu-like symptoms as well as pain at the injection site. The reactions were mild to moderate in severity; 2% of people had severe reactions and these were generally cellulitis.
Talimogene laherparepvec is a genetically engineered herpes virus (an oncolytic herpes virus). Two genes were removed – one that shuts down an individual cell's defenses, and another that helps the virus evade the immune system – and a gene for human GM-CSF was added. The drug works by replicating in cancer cells, causing them to burst; it was also designed to stimulate an immune response against the patient's cancer, which has been demonstrated by multiple pieces of data, including regression of tumors which have not been injected with talimogene laherparepvec.
The drug was created and initially developed by BioVex, Inc. and was continued by Amgen, which acquired BioVex i |
https://en.wikipedia.org/wiki/Enzyme%20replacement%20therapy | Enzyme replacement therapy (ERT) is a medical treatment which replaces an enzyme that is deficient or absent in the body. Usually, this is done by giving the patient an intravenous (IV) infusion of a solution containing the enzyme.
ERT is available for some lysosomal storage diseases: Gaucher disease, Fabry disease, MPS I, MPS II (Hunter syndrome), MPS VI and Pompe disease. ERT does not correct the underlying genetic defect, but it increases the concentration of the enzyme that the patient is lacking. ERT has also been used to treat patients with severe combined immunodeficiency (SCID) resulting from an adenosine deaminase deficiency (ADA-SCID).
Other treatment options for patients with enzyme or protein deficiencies include substrate reduction therapy, gene therapy, and bone-marrow derived stem cell transplantation.
History
ERT was developed in 1964 by Christian de Duve and Roscoe Brady. Leading work was done on this subject at the Department of Physiology at the University of Alberta by Mark J. Poznansky and Damyanti Bhardwaj, where a model for enzyme therapy was developed using rats. ERT was not used in clinical practice until 1991, after the FDA gave orphan drug approval for the treatment of Gaucher disease with Alglucerase. ERTs were initially manufactured by isolating the therapeutic enzyme from human placenta. The FDA has approved ERTs that are derived from other human cells, animal cells (i.e. Chinese hamster ovary cells, or CHO cells), and plant cells.
Medical uses
Lysosomal storage diseases are a group of diseases and a main application of ERT. Lysosomes are cellular organelles that are responsible for the metabolism of many different macromolecules and proteins. They use enzymes to break down macromolecules, which are recycled or disposed. As of 2012, there are 50 lysosomal storage diseases, and more are still being discovered. These disorders arise because of genetic mutations that prevent the production of certain enzymes used in the lysoso |
https://en.wikipedia.org/wiki/Cyclotron | A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying electric field. Lawrence was awarded the 1939 Nobel Prize in Physics for this invention.
The cyclotron was the first "cyclical" accelerator. The primary accelerators before the development of the cyclotron were electrostatic accelerators, such as the Cockcroft–Walton generator and the Van de Graaff generator. In these accelerators, particles would cross an accelerating electric field only once. Thus, the energy gained by the particles was limited by the maximum electrical potential that could be achieved across the accelerating region. This potential was in turn limited by electrostatic breakdown to a few million volts. In a cyclotron, by contrast, the particles encounter the accelerating region many times by following a spiral path, so the output energy can be many times the energy gained in a single accelerating step.
Cyclotrons were the most powerful particle accelerator technology until the 1950s, when they were surpassed by the synchrotron. Nonetheless they are still widely used to produce particle beams for nuclear medicine and basic research. As of 2020, close to 1,500 cyclotrons were in use worldwide for the production of radionuclides for nuclear medicine. In addition, cyclotrons can be used for particle therapy, where particle beams are directly applied to patients.
History
In 1927, while a student at Kiel, German physicist Max Steenbeck was the first to formulate the concept of the cyclotron, but he was discouraged from pursuing the idea further. In late 1928 and early 1929, Hungarian physicist Leo Szilárd filed patent applications in Germany for the linear accelerator |
https://en.wikipedia.org/wiki/Product%20category | In the mathematical field of category theory, the product of two categories C and D, denoted and called a product category, is an extension of the concept of the Cartesian product of two sets. Product categories are used to define bifunctors and multifunctors.
Definition
The product category has:
as objects:
pairs of objects , where A is an object of C and B of D;
as arrows from to :
pairs of arrows , where is an arrow of C and is an arrow of D;
as composition, component-wise composition from the contributing categories:
;
as identities, pairs of identities from the contributing categories:
1(A, B) = (1A, 1B).
Relation to other categorical concepts
For small categories, this is the same as the action on objects of the categorical product in the category Cat. A functor whose domain is a product category is known as a bifunctor. An important example is the Hom functor, which has the product of the opposite of some category with the original category as domain:
Hom : Cop × C → Set.
Generalization to several arguments
Just as the binary Cartesian product is readily generalized to an n-ary Cartesian product, binary product of two categories can be generalized, completely analogously, to a product of n categories. The product operation on categories is commutative and associative, up to isomorphism, and so this generalization brings nothing new from a theoretical point of view. |
https://en.wikipedia.org/wiki/Just%20enough%20operating%20system | Just enough operating system (JeOS, pronounced "juice" according to SUSE) is a paradigm for customizing operating systems to fit the needs of a particular application such as for a software appliance. The platform only includes the operating system components required to support a particular application and any other third-party components contained in the appliance (e.g., the kernel). This makes the appliance smaller, faster (to boot and to execute the particular application) and potentially more secure than an application running under a full general-purpose OS.
Common implementations
Typically, a JeOS will consist of the following:
JeOS media (OS core [kernel, virtual drives, login])
OS minimum maintenance tools
Minimum user space tools
Packages repository (DVD or network based)
It is important to differentiate between true fully minimalized OS install profiles forced, for example, with security hardening tools or representing Recovery Console images and JeOS richer install profiles which are designed and built for wider audience usage, so VM/VA creators and their users can easily perform needed installation or configuration tasks.
Differences between minimialist, lightweight and appliance
Light-weight Linux distribution
minimalist e.g. Porteus (operating system)
See also
BareMetal
Container Linux (discontinued)
OpenELEC (JeOS software appliance with Kodi Media Center)
LibreELEC (JeOS software appliance with Kodi Media Center)
Ubuntu JeOS
Containerization (computing) (modern retake on JeOS) |
https://en.wikipedia.org/wiki/List%20of%20router%20firmware%20projects | List of software created and maintained by people other than the manufacturer of the product. The extent of support for (and testing on) particular hardware varies from project to project.
Embedded
Notable custom-firmware projects for wireless routers.
Many of these will run on various brands such as Linksys, Asus, Netgear, etc.
OpenWrt – Customizable FOSS firmware written from scratch; features a combined SquashFS/JFFS2 file system and the package manager opkg with over 3000 available packages (Linux/GPL); now merged with LEDE.
LEDE – A fork of the OpenWrt project that shared many of the same goals; merged back into OpenWrt as of v. 18.06 (2018).
Commotion Wireless – FOSS mesh networking.
DD-WRT – Based on OpenWrt kernel since v. 23 (Dec. 2005), paid and free versions available.
Gargoyle – A free OpenWrt-based Linux distribution for a range of Broadcom and Atheros chipset based wireless routers.
LibreCMC – An FSF-endorsed derivation of OpenWRT with the proprietary blobs removed
Roofnet – A now defunct experimental 802.11 based mesh network project developed at the MIT Computer Science and Artificial Intelligence Laboratory. The technology developed by the Roofnet project formed the basis for the company Meraki, now owned by Cisco.
DebWRT – A discontinued project that combines the Linux kernel from OpenWrt and the package management system from Debian (Linux/GPL).
HyperWRT – Early power-boosting firmware project to stay close to the official WRT54G and WRT54GS firmware but add features such as transmit power, port triggers, scripts, telnet, etc.
Tomato – The successor to HyperWRT, features advanced QoS as well as Ajax and SVG graphs.
Asuswrt
Asuswrt-Merlin
Other
Software distributions for routers with >5 GB Storage and >1 GB RAM
FreeBSD
m0n0wall - m0n0wall is abandoned, but it was built on FreeBSD and boots off of flash storage or CD ROM media in under 12 megabytes.
pfsense - an open source firewall/router computer software distribution based on Free |
https://en.wikipedia.org/wiki/Carlo%20Ghezzi | Carlo Ghezzi is an emeritus professor and former chair of software engineering at the Politecnico di Milano, Italy, and an adjunct professor at the Università della Svizzera italiana (USI), Switzerland. At the Politecnico, he has been the Rector's Delegate for research, department chair, head of the PhD program, and member of the academic senate and of the board of governors of Politecnico.
Education and academic career
He received his Dr.Eng. degree in electrical engineering from the Politecnico di Milano, where he spent most of his professional life, as assistant, associate, and full professor. He also taught and did research in other institutions: University of California, Los Angeles, US (1976), University of North Carolina at Chapel Hill, USA (1979–80), Università degli Studi di Padova, Italy (1980–81), Escuela Superior Latinoamericana de Informática, Argentina (1990), University of California, Santa Barbara, US (1991), Technical University of Vienna, Austria (1996), and University of Klagenfurt, Austria (1996).
Ghezzi is a 1999 ACM fellow (citation: "Numerous research contributions from compiler theory to real-time systems to software processes. A strong contributor to the software engineering community in Europe and worldwide.") and 2006 IEEE Fellow (citation: "for contributions to programming languages and software engineering"). In 2006, he was awarded the ACM SIGSOFT Distinguished Service Award. He is a Member of Istituto Lombardo Accademia di Scienze e Lettere.
Professional service
He is a regular member of the program committee of important conferences of the software engineering field, such as the International Conference on Software Engineering (ICSE) and the Foundations of Software Engineering (FSE) conference, jointly held in conjunction with the European Software Engineering Conference (ESEC).
He has been chairing such conferences as program co-chair (ICSE 1991), program chair (ESEC/FSE '99), general chair (ICSE 2000), and general co-chair ( |
https://en.wikipedia.org/wiki/Least%20squares | The method of least squares is a standard approach in regression analysis to approximate the solution of overdetermined systems (sets of equations in which there are more equations than unknowns) by minimizing the sum of the squares of the residuals (a residual being the difference between an observed value and the fitted value provided by a model) made in the results of each individual equation.
The most important application is in data fitting. When the problem has substantial uncertainties in the independent variable (the x variable), then simple regression and least-squares methods have problems; in such cases, the methodology required for fitting errors-in-variables models may be considered instead of that for least squares.
Least squares problems fall into two categories: linear or ordinary least squares and nonlinear least squares, depending on whether or not the residuals are linear in all unknowns. The linear least-squares problem occurs in statistical regression analysis; it has a closed-form solution. The nonlinear problem is usually solved by iterative refinement; at each iteration the system is approximated by a linear one, and thus the core calculation is similar in both cases.
Polynomial least squares describes the variance in a prediction of the dependent variable as a function of the independent variable and the deviations from the fitted curve.
When the observations come from an exponential family with identity as its natural sufficient statistics and mild-conditions are satisfied (e.g. for normal, exponential, Poisson and binomial distributions), standardized least-squares estimates and maximum-likelihood estimates are identical. The method of least squares can also be derived as a method of moments estimator.
The following discussion is mostly presented in terms of linear functions but the use of least squares is valid and practical for more general families of functions. Also, by iteratively applying local quadratic approximation to the lik |
https://en.wikipedia.org/wiki/Rubus%20tricolor | Rubus tricolor () is an evergreen prostrate shrub, native to southwestern China. Leaves are dark green above, pale green below, and stems have red bristles. It has white flowers in summer and edible red fruit. It grows approximately high and usually forming a vigorously spreading, dense mat. In cultivation, it is mainly used as groundcover. Common names include Chinese bramble, groundcover bramble, creeping bramble, Korean raspberry, Himalayan bramble, and groundcover raspberry. In Chinese, it is called ("").
Description
Morphology
The growth habit is prostrate/procumbent (trailing along the ground), but also climbing. It is usually stated to be an evergreen shrub, but sometimes said to be semi-evergreen, or deciduous. This is because it is normally evergreen but can shed its leaves in severe winters. The long stems arch between 30 cm (~1 ft) and 60 cm (~2 ft) high, although it may get higher if it grows over itself or other shrubs. The tips root when they touch the ground. It grows at a fast rate, spreading up to 2 m (6 ft 6 inches) per year. It tends to form a dense, creeping mat, of sprawling shrubs growing into each other.
The stems are tomentose, having dense yellow-brown bristles, but are not prickly. Leaf petioles are 1.5-4 cm long, and similarly bristled, with glandular hairs and persistent stipules approximately 1–2 cm by 4–8 mm.
Leaves are alternate (each leaf arises at a different node). Leaf shape is simple (undivided blade) or slightly undulate (3-5 shallow lobes), ovate to oblong, with base subrounded to cordate and apex shortly acuminate (see: Leaf shapes). More simply, leaves have a heart-shaped base and a pointed tip. The margins of the leaf are described as unevenly coarsely sharply serrate (see: Leaf margin). Leaves are approximately 6–12 by 3–8 cm in size. On the abaxial (under) surface, the colour is yellow-grey and there are bristles, particularly on the veins which are raised. Adaxially (upper surface), the leaf is dark green, glossy an |
https://en.wikipedia.org/wiki/Allen%20Telescope%20Array | The Allen Telescope Array (ATA), formerly known as the One Hectare Telescope (1hT), is a radio telescope array dedicated to astronomical observations and a simultaneous search for extraterrestrial intelligence (SETI). The array is situated at the Hat Creek Radio Observatory in Shasta County, northeast of San Francisco, California.
The project was originally developed as a joint effort between the SETI Institute and the Radio Astronomy Laboratory (RAL) at the University of California, Berkeley (UC Berkeley), with funds obtained from an initial 12.5 million donation by the Paul G. Allen Family Foundation and Nathan Myhrvold. The first phase of construction was completed and the ATA finally became operational on 11 October 2007 with 42 antennas (ATA-42), after Paul Allen (co-founder of Microsoft) had pledged an additional $13.5 million to support the construction of the first and second phases.
Although overall Allen has contributed more than $30 million to the project, it has not succeeded in building the 350 6.1 m (20 ft) dishes originally conceived, and the project suffered an operational hiatus due to funding shortfalls between April and August 2011, after which observations resumed. Subsequently, UC Berkeley exited the project, completing divestment in April 2012. The facility is now managed by SRI International (formerly Stanford Research Institute), an independent, nonprofit research institute. As of 2016, the SETI Institute performs observations with the ATA between the hours of 6 pm and 6 am daily.
In August 2014, the installation was threatened by a forest fire in the area and was briefly forced to shut down, but ultimately emerged largely unscathed.
Overview
First conceived by SETI pioneer Frank Drake, the idea has been a dream of the SETI Institute for years. However, it was not until early 2001 that research and development began, after a donation of $11.5 million by the Paul G. Allen Family Foundation. In March 2004, following the successful comple |
https://en.wikipedia.org/wiki/Weighted%20matroid | In combinatorics, a branch of mathematics, a weighted matroid is a matroid endowed with function with respect to which one can perform a greedy algorithm.
A weight function for a matroid assigns a strictly positive weight to each element of . We extend the function to subsets of by summation; is the sum of over in . A matroid with an associated weight function is called a weighted matroid.
Spanning forest algorithms
As a simple example, say we wish to find the maximum spanning forest of a graph. That is, given a graph and a weight for each edge, find a forest containing every vertex and maximizing the total weight of the edges in the tree. This problem arises in some clustering applications. If we look at the definition of the forest matroid above, we see that the maximum spanning forest is simply the independent set with largest total weight — such a set must span the graph, for otherwise we can add edges without creating cycles. But how do we find it?
Finding a basis
There is a simple algorithm for finding a basis:
Initially let be the empty set.
For each in
if is independent, then set to .
The result is clearly an independent set. It is a maximal independent set because if is not independent for some subset of , then is not independent either (the contrapositive follows from the hereditary property). Thus if we pass up an element, we'll never have an opportunity to use it later. We will generalize this algorithm to solve a harder problem.
Extension to optimal
An independent set of largest total weight is called an optimal set. Optimal sets are always bases, because if an edge can be added, it should be; this only increases the total weight. As it turns out, there is a trivial greedy algorithm for computing an optimal set of a weighted matroid. It works as follows:
Initially let be the empty set.
For each in , taken in (monotonically) decreasing order by weight
if is independent, then set to .
This algorithm finds a basis, since it |
https://en.wikipedia.org/wiki/Relativistic%20speed | Relativistic speed refers to speed at which relativistic effects become significant to the desired accuracy of measurement of the phenomenon being observed. Relativistic effects are those discrepancies between values calculated by models considering and not considering relativity. Related words are velocity, rapidity, and celerity which is proper velocity. Speed is a scalar, being the magnitude of the velocity vector which in relativity is the four-velocity and in three-dimension Euclidean space a three-velocity. Speed is empirically measured as average speed, although current devices in common use can estimate speed over very small intervals and closely approximate instantaneous speed. Non-relativistic discrepancies include cosine error which occurs in speed detection devices when only one scalar component of the three-velocity is measured and the Doppler effect which may affect observations of wavelength and frequency. Relativistic effects are highly non-linear and for everyday purposes are insignificant because the Newtonian model closely approximates the relativity model. In special relativity the Lorentz factor is a measure of time dilation, length contraction and the relativistic mass increase of a moving object.
See also
Lorentz factor
Relative velocity
Relativistic beaming
Relativistic jet
Relativistic mass
Relativistic particle
Relativistic plasma
Relativistic wave equations
Special relativity
Ultrarelativistic limit |
https://en.wikipedia.org/wiki/Stable%20model%20category | In category theory, a branch of mathematics, a stable model category is a pointed model category in which the suspension functor is an equivalence of the homotopy category with itself.
The prototypical examples are the category of spectra in the stable homotopy theory and the category of chain complex of R-modules. On the other hand, the category of pointed topological spaces and the category of pointed simplicial sets are not stable model categories.
Any stable model category is equivalent to a category of presheaves of spectra. |
https://en.wikipedia.org/wiki/Pelolinea | Pelolinea is a bacteria genus from the family of Anaerolineaceae with one known species (Pelolinea submarina). Pelolinea submarina has been isolated from marine sediments from the Shimokita Peninsula. |
https://en.wikipedia.org/wiki/JIS%20encoding | In computing, JIS encoding refers to several Japanese Industrial Standards for encoding the Japanese language. Strictly speaking, the term means either:
A set of standard coded character sets for Japanese, notably:
JIS X 0201, the Japanese version of ISO 646 (ASCII) containing the base 7-bit ASCII characters (with some modifications) and 64 half-width katakana characters.
JIS X 0208, the most common kanji character set containing 6,879 characters, including 6,355 kanji and 524 other characters (one 94 by 94 plane)
JIS X 0212, a supplement for JIS X 0208 which adds 5,801 kanji, totaling 12,156 kanji (a second 94 by 94 plane)
JIS X 0213, which extends JIS X 0208 (two planes)
JIS X 0202 (also known as ISO-2022-JP), a set of encoding mechanisms for sending JIS character data over transmission mediums that only support 7-bit data.
In practice, "JIS encoding" usually refers to JIS X 0208 character data encoded with JIS X 0202. For instance, the IANA uses the JIS_Encoding label to refer to JIS X 0202, and the ISO-2022-JP label to refer to the profile thereof defined by .
Other encoding mechanisms for JIS characters include the Shift JIS encoding and EUC-JP. Shift JIS adds the kanji, full-width hiragana and full-width katakana from JIS X 0208 to JIS X 0201 in a backward compatible way. Shift JIS is perhaps the most widely used encoding in Japan, as the compatibility with the single-byte JIS X 0201 character set made it possible for electronic equipment manufacturers (such as cash register manufacturers) to offer an upgrade from older cheaper equipment that was not capable of displaying kanji to newer equipment while retaining character-set compatibility.
EUC-JP is used on UNIX systems, where the JIS encodings are incompatible with POSIX standards.
A more recent alternative to JIS coded characters is Unicode (UCS coded characters), particularly in the UTF-8 encoding mechanism.
Encoding comparison
The following table compares the features of the three main encodin |
https://en.wikipedia.org/wiki/Quantum%20Experiments%20using%20Satellite%20Technology | Quantum Experiment using Satellite Technology launched in 2017 by Raman Research Institute in February 2021 demonstrated Quantum communication for 50 m apart and on 19 March 2021 for 300 m apart inline of sight in Space Applications Centre in coordination with Indian Space Research Organisation ,Indian Institute of Science and Tata Institute of Fundamental Research,. India 's first project on satellite based long distance Quantum communication,
Technical specifications
Indigenously developed NAVIC receiver for time synchronization
Gimbal mechanism system instead of large aperture telescope for optical alignment.
Shared Quantum secure text.
Shared image transmission.
Quantum assisted two ways video conferencing at Space Applications Centre and Physical Research Laboratory
It used robust and high brightness entangled photon source, used BBM92 protocol implementation NAVIC enabled synchronization polarization compensation technique.
It is hack proof as it uses Quantum key distribution.
It uses Quantum cryptography and carried out by Quantum information and computing (QuIC) lab . |
https://en.wikipedia.org/wiki/P-adic%20modular%20form | In mathematics, a p-adic modular form is a p-adic analog of a modular form, with coefficients that are p-adic numbers rather than complex numbers. introduced p-adic modular forms as limits of ordinary modular forms, and shortly afterwards gave a geometric and more general definition. Katz's p-adic modular forms include as special cases classical p-adic modular forms, which are more or less p-adic linear combinations of the usual "classical" modular forms, and overconvergent p-adic modular forms, which in turn include Hida's ordinary modular forms as special cases.
Serre's definition
Serre defined a p-adic modular form to be a formal power series with p-adic coefficients that is a p-adic limit of classical modular forms with integer coefficients. The weights of these classical modular forms need not be the same; in fact, if they are then the p-adic modular form is nothing more than a linear combination of classical modular forms. In general the weight of a p-adic modular form is a p-adic number, given by the limit of the weights of the classical modular forms (in fact a slight refinement gives a weight in Zp×Z/(p–1)Z).
The p-adic modular forms defined by Serre are special cases of those defined by Katz.
Katz's definition
A classical modular form of weight k can be thought of roughly as a function f from pairs (E,ω) of a complex elliptic curve with a holomorphic 1-form ω to complex numbers, such that f(E,λω) = λ−kf(E,ω), and satisfying some additional conditions such as being holomorphic in some sense.
Katz's definition of a p-adic modular form is similar, except that E is now an elliptic curve over some algebra R (with p nilpotent) over the ring of integers R0 of a finite extension of the p-adic numbers, such that E is not supersingular, in the sense that the Eisenstein series Ep–1 is invertible at (E,ω). The p-adic modular form f now takes values in R rather than in the complex numbers. The p-adic modular form also has to satisfy some other conditions analog |
https://en.wikipedia.org/wiki/Ni%20Wei-tou | Ni Wei-tou (; born 1944 in Zhenhai, Ningbo, Zhejiang) is a Taiwanese physicist, who graduated from the Department of Physics of National Taiwan University (NTU), and got his PhD of Physics & Mathematics from California Institute of Technology. After his retirement on 1 October 2000, he is now appointed as a professor emeritus of the Department of Physics of National Tsing Hua University (NTHU) at Hsinchu, Taiwan, since 2006.
He is an expert of theoretical and experimental gravitational physics, astrophysics, cosmology, particle physics, and quantum optics etc. He is famous for his alternative theories of gravitation to general relativity, such as Ni (1972), Ni (1973), and Lee, Lightman & Ni (1974). He has been devoted to popular science in Taiwan.
Books
2017 One Hundred Years of General Relativity: From Genesis and Empirical Foundations to Gravitational Waves, Cosmology and Quantum Gravity (The 2 Volumes) |
https://en.wikipedia.org/wiki/Intransitive%20dice | A set of dice is intransitive (or nontransitive) if it contains three dice, A, B, and C, with the property that A rolls higher than B more than half the time, and B rolls higher than C more than half the time, but it is not true that A rolls higher than C more than half the time. In other words, a set of dice is intransitive if the binary relation – rolls a higher number than more than half the time – on its elements is not transitive. More simply, A normally beats B, B normally beats C, but A does not normally beat C.
It is possible to find sets of dice with the even stronger property that, for each die in the set, there is another die that rolls a higher number than it more than half the time. This is different in that instead of only "A does not normally beat C" it is now "C normally beats A". Using such a set of dice, one can invent games which are biased in ways that people unused to intransitive dice might not expect (see Example).
Example
Consider the following set of dice.
Die A has sides 2, 2, 4, 4, 9, 9.
Die B has sides 1, 1, 6, 6, 8, 8.
Die C has sides 3, 3, 5, 5, 7, 7.
The probability that A rolls a higher number than B, the probability that B rolls higher than C, and the probability that C rolls higher than A are all , so this set of dice is intransitive. In fact, it has the even stronger property that, for each die in the set, there is another die that rolls a higher number than it more than half the time.
Now, consider the following game, which is played with a set of dice.
The first player chooses a die from the set.
The second player chooses one die from the remaining dice.
Both players roll their die; the player who rolls the higher number wins.
If this game is played with a transitive set of dice, it is either fair or biased in favor of the first player, because the first player can always find a die that will not be beaten by any other dice more than half the time. If it is played with the set of dice described above, however, the g |
https://en.wikipedia.org/wiki/Proofs%20of%20Fermat%27s%20little%20theorem | This article collects together a variety of proofs of Fermat's little theorem, which states that
for every prime number p and every integer a (see modular arithmetic).
Simplifications
Some of the proofs of Fermat's little theorem given below depend on two simplifications.
The first is that we may assume that is in the range . This is a simple consequence of the laws of modular arithmetic; we are simply saying that we may first reduce modulo . This is consistent with reducing modulo , as one can check.
Secondly, it suffices to prove that
for in the range . Indeed, if the previous assertion holds for such , multiplying both sides by yields the original form of the theorem,
On the other hand, if or , the theorem holds trivially.
Combinatorial proofs
Proof by counting necklaces
This is perhaps the simplest known proof, requiring the least mathematical background. It is an attractive example of a combinatorial proof (a proof that involves counting a collection of objects in two different ways).
The proof given here is an adaptation of Golomb's proof.
To keep things simple, let us assume that is a positive integer. Consider all the possible strings of symbols, using an alphabet with different symbols. The total number of such strings is , since there are possibilities for each of positions (see rule of product).
For example, if and , then we can use an alphabet with two symbols (say and ), and there are strings of length 5:
, , , , , , , ,
, , , , , , , ,
, , , , , , , ,
, , , , , , , .
We will argue below that if we remove the strings consisting of a single symbol from the list (in our example, and ), the remaining strings can be arranged into groups, each group containing exactly strings. It follows that is divisible by .
Necklaces
Let us think of each such string as representing a necklace. That is, we connect the two ends of the string together and regard two strings as the same necklace if we can rotate one string to obtain the sec |
https://en.wikipedia.org/wiki/List%20of%20incomplete%20proofs | This page lists notable examples of incomplete published mathematical proofs. Most of these were accepted as correct for several years but later discovered to contain gaps. There are both examples where a complete proof was later found and where the alleged result turned out to be false.
Results later proved rigorously
Euclid's Elements. Euclid's proofs are essentially correct, but strictly speaking sometimes contain gaps because he tacitly uses some unstated assumptions, such as the existence of intersection points. In 1899 David Hilbert gave a complete set of (second order) axioms for Euclidean geometry, called Hilbert's axioms, and between 1926 and 1959 Tarski gave some complete sets of first order axioms, called Tarski's axioms.
Isoperimetric inequality. For three dimensions it states that the shape enclosing the maximum volume for its surface area is the sphere. It was formulated by Archimedes but not proved rigorously until the 19th century, by Hermann Schwarz.
Infinitesimals. In the 18th century there was widespread use of infinitesimals in calculus, though these were not really well defined. Calculus was put on firm foundations in the 19th century, and Robinson put infinitesimals in a rigorous basis with the introduction of nonstandard analysis in the 20th century.
Fundamental theorem of algebra (see History). Many incomplete or incorrect attempts were made at proving this theorem in the 18th century, including by d'Alembert (1746), Euler (1749), de Foncenex (1759), Lagrange (1772), Laplace (1795), Wood (1798), and Gauss (1799). The first rigorous proof was published by Argand in 1806.
Dirichlet's theorem on arithmetic progressions. In 1808 Legendre published an attempt at a proof of Dirichlet's theorem, but as Dupré pointed out in 1859 one of the lemmas used by Legendre is false. Dirichlet gave a complete proof in 1837.
The proofs of the Kronecker–Weber theorem by Kronecker (1853) and Weber (1886) both had gaps. The first complete proof was given |
https://en.wikipedia.org/wiki/Television%20channel%20frequencies | The following tables show the frequencies assigned to broadcast television channels in various regions of the world, along with the ITU letter designator for the system used. The frequencies shown are for the analogue video and audio carriers. The channel itself occupies several megahertz of bandwidth. For example, North American channel 1 occupies the spectrum from 44 to 50 MHz. See Broadcast television systems for a table of signal characteristics, including bandwidth, by ITU letter designator.
International normalization for analog TV systems
International broadcasting television frenquencies are divided in two part of the spectrum; the Very high frequency or "VHF“ band and the Ultra high frequency or "UHF“ band.
VHF
Americas (most countries), South Korea, Taiwan, Myanmar, and the Philippines
During World War II, the frequencies originally assigned as channels 13 to 18 were appropriated by the U.S. military, which still uses them to this day. It was also decided to move the allocation for FM radio from the 42-50 MHz band to a larger 88-106 MHz band (later extended to the current 88-108 MHz FM band). This required a reassignment of the VHF channels to the plan currently in use.
Assignments since February 25, 1946
System M 525 lines (most countries in the Americas and Caribbean, South Korea, Taiwan and the Philippines)
System N 625 lines (used in Argentina, Paraguay and Uruguay)
FM channel 200, 87.9 MHz, overlaps TV 6. This is used only by K200AA. Channel 6A is only used in South Korea and the Philippines.
TV 6 analog audio can be heard on FM 87.75 on most broadcast radio receivers as well as on a European TV tuned to channel 4A or channel C, but at lower volume than wideband FM broadcast stations, because of the lower deviation.
Channel 1 audio is the same as European Channel 2 audio and the video is the same as European Channel 2A. Channel 2 video is the same as European Channel 3 video.
Japan
The frequency spacing for each channel is 6 MHz as th |
https://en.wikipedia.org/wiki/Rybicki%20Press%20algorithm | The Rybicki–Press algorithm is a fast algorithm for inverting a matrix whose entries are given by , where and where the are sorted in order. The key observation behind the Rybicki-Press observation is that the matrix inverse of such a matrix is always a tridiagonal matrix (a matrix with nonzero entries only on the main diagonal and the two adjoining ones), and tridiagonal systems of equations can be solved efficiently (to be more precise, in linear time). It is a computational optimization of a general set of statistical methods developed to determine whether two noisy, irregularly sampled data sets are, in fact, dimensionally shifted representations of the same underlying function. The most common use of the algorithm is in the detection of periodicity in astronomical observations, such as for detecting quasars.
The method has been extended to the Generalized Rybicki-Press algorithm for inverting matrices with entries of the form . The key observation in the Generalized Rybicki-Press (GRP) algorithm is that the matrix is a semi-separable matrix with rank (that is, a matrix whose upper half, not including the main diagonal, is that of some matrix with matrix rank and whose lower half is also that of some possibly different rank matrix) and so can be embedded into a larger band matrix (see figure on the right), whose sparsity structure can be leveraged to reduce the computational complexity. As the matrix has a semi-separable rank of , the computational complexity of solving the linear system or of calculating the determinant of the matrix scales as , thereby making it attractive for large matrices.
The fact that matrix is a semi-separable matrix also forms the basis for library, which is a library for fast and scalable Gaussian process regression in one dimension with implementations in C++, Python, and Julia. The method also provides an algorithm for generating samples from a high-dimensional distribution. The method has found attractive applications |
https://en.wikipedia.org/wiki/Eremosphaera | Eremosphaera is a genus of green algae in the family Oocystaceae. |
https://en.wikipedia.org/wiki/Metabiaugmented%20hexagonal%20prism | In geometry, the metabiaugmented hexagonal prism is one of the Johnson solids (). As the name suggests, it can be constructed by doubly augmenting a hexagonal prism by attaching square pyramids () to two of its nonadjacent, nonparallel equatorial faces. Attaching the pyramids to opposite equatorial faces yields a parabiaugmented hexagonal prism. (The solid obtained by attaching pyramids to adjacent equatorial faces is not convex, and thus not a Johnson solid.)
See also
Hexagonal prism
External links
Johnson solids |
https://en.wikipedia.org/wiki/Vaginal%20flora%20in%20pregnancy | The vaginal flora in pregnancy, or vaginal microbiota in pregnancy, is different from the vaginal flora (the population of microorganisms that resides in the vagina) before sexual maturity, during reproductive years, and after menopause. A description of the vaginal flora of pregnant women who are immunocompromised is not covered in this article. The composition of the vaginal flora significantly differs in pregnancy. Bacteria or viruses that are infectious most often have no symptoms.
Normal microbiota
Microbiota in pregnancy
In normal pregnancy, the resident vaginal flora is thought to provide protection against infection. The microbiota during pregnancy are predominantly Lactobacillus species. Microbiota composition can change during the course of the pregnancy. If the microbiota populations become more diverse, indicating that the normal Lactobacillus-dominated population has changed to a bacterial vaginosis population, risks of adverse pregnancy outcomes increase. Vaginal discharge is common during pregnancy but is not an indicator of bacterial vaginosis or abnormal microbiota. The treatment of abnormal vaginal microbiota populations with lactobacilli and estriol during pregnancy was found to restore the microbiota to a normal state.
Bacterial vaginosis and pregnancy
Bacterial vaginosis in pregnancy is an alteration of the normal vaginal microbiota of pregnancy. Intrauterine infections in pregnancy are caused by bacteria that cause inflammation. The women may experience few or no symptoms. This sometimes leads to chorioamnionitis and other negative pregnancy outcomes. Chorioamnionitis is due to the presence of bacteria such as Ureaplasma parvum and Mycoplasma species this generates the release of proinflammatory cytokines and chemokines, IL-8 which causes cervical ripening and can result in premature birth. When there are high bacterial counts in of the vagina during pregnancy is typically due to the presence of the following organisms:
Gardnerella vaginali |
https://en.wikipedia.org/wiki/Clinical%20metagenomic%20sequencing | Clinical metagenomic next-generation sequencing (mNGS) is the comprehensive analysis of microbial and host genetic material (DNA or RNA) in clinical samples from patients by next-generation sequencing. It uses the techniques of metagenomics to identify and characterize the genome of bacteria, fungi, parasites, and viruses without the need for a prior knowledge of a specific pathogen directly from clinical specimens. The capacity to detect all the potential pathogens in a sample makes metagenomic next generation sequencing a potent tool in the diagnosis of infectious disease especially when other more directed assays, such as PCR, fail. Its limitations include clinical utility, laboratory validity, sense and sensitivity, cost and regulatory considerations.
Outside of clinical medicine, similar work is done to identify genetic material in environmental samples, such as ponds or soil.
Definition
Next-generation sequencing uses the techniques of metagenomics to identify and characterize the genome of bacteria, fungi, parasites, and viruses without the need for a prior knowledge of a specific pathogen directly from clinical specimens. The capacity to detect all the potential pathogens in a sample makes metagenomic next generation sequencing a potent tool in the diagnosis of infectious disease especially when other more directed assays, such as PCR, fail.
Laboratory workflow
A typical mNGS workflow consists of the following steps:
Sample acquisition: the most commonly used samples for metagenomic sequencing are blood, stool, cerebrospinal fluid (CSF), urine, or nasopharyngeal swabs. Among these, blood and CSF are the cleanest, having less background noise, while the others are expected to have a great amount of commensals and/or opportunistic infections and thus have more background noise. Samples should be collected with much caution as surgical specimens could be contaminated during handling of the biopsy; for example, lumbar punctures to obtain CSF specimens may b |
https://en.wikipedia.org/wiki/Pharyngobasilar%20fascia | The pharyngobasilar fascia is a fascia of the pharynx. It is situated between the mucous and muscular layers of the pharynx. It is formed as a thickening of the pharyngeal mucosa superior to the superior pharyngeal constrictor muscle. It attaches to the basilar part of occipital bone, the petrous part of the temporal bone (medial to the pharyngotympanic tube), the (posterior border of the) medial pterygoid plate, and the pterygomandibular raphe. It diminishes in thickness inferiorly. Posteriorly, it is reinforced by the pharyngeal raphe. It reinforces the pharyngeal wall where muscle is deficient.
Additional images
See also
Buccopharyngeal fascia |
https://en.wikipedia.org/wiki/Structured%20cabling | In telecommunications, structured cabling is building or campus cabling infrastructure that consists of a number of standardized smaller elements (hence structured) called subsystems. Structured cabling components include twisted pair and optical cabling, patch panels and patch cables.
Overview
Structured cabling is the design and installation of a cabling system that will support multiple hardware uses and be suitable for today's needs and those of the future. With a correctly installed system, current and future requirements can be met, and hardware that is added in the future will be supported
Structured cabling design and installation is governed by a set of standards that specify wiring data centers, offices, and apartment buildings for data or voice communications using various kinds of cable, most commonly category 5e (Cat 5e), category 6 (Cat 6), and fiber optic cabling and modular connectors. These standards define how to lay the cabling in various topologies in order to meet the needs of the customer, typically using a central patch panel (which is normally 19-inch rack-mounted), from where each modular connection can be used as needed. Each outlet is then patched into a network switch (normally also rack-mounted) for network use or into an IP or PBX (private branch exchange) telephone system patch panel.
Lines patched as data ports into a network switch require simple straight-through patch cables at each end to connect a computer. Voice patches to PBXs in most countries require an adapter at the remote end to translate the configuration on 8P8C modular connectors into the local standard telephone wall socket. No adapter is needed in North America as the 6P2C and 6P4C plugs most commonly used with RJ11 and RJ14 telephone connections are physically and electrically compatible with the larger 8P8C socket. RJ25 and RJ61 connections are physically but not electrically compatible, and cannot be used. In the United Kingdom, an adapter must be present at |
https://en.wikipedia.org/wiki/TRIAC | A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three-terminal electronic component that conducts current in either direction when triggered. The term TRIAC is a genericised trademark.
TRIACs are a subset of thyristors (analogous to a relay in that a small voltage and current can control a much larger voltage and current) and are related to silicon controlled rectifiers (SCRs). TRIACs differ from SCRs in that they allow current flow in both directions, whereas an SCR can only conduct current in a single direction. Most TRIACs can be triggered by applying either a positive or negative voltage to the gate (an SCR requires a positive voltage). Once triggered, SCRs and TRIACs continue to conduct, even if the gate current ceases, until the main current drops below a certain level called the holding current.
Gate turn-off thyristors (GTOs) are similar to TRIACs but provide more control by turning off when the gate signal ceases.
The bidirectionality of TRIACs makes them convenient switches for alternating-current (AC). In addition, applying a trigger at a controlled phase angle of the AC in the main circuit allows control of the average current flowing into a load (phase control). This is commonly used for controlling the speed of a universal motor, dimming lamps, and controlling electric heaters. TRIACs are Bipolar devices.
Operation
To understand how TRIACs work, consider the triggering in each of the four possible combinations of gate and MT2 voltages with respect MT1. The four separate cases (quadrants) are illustrated in Figure 1. Main Terminal 1 (MT1) and Main Terminal (MT2) are also referred to as Anode 1 (A1) and Anode 2 (A2) respectively.
The relative sensitivity depends on the physical structure of a particular triac, but as a rule, quadrant I is the most sensitive (least gate current required), and quadrant 4 is the least sensitive (most gate current required).
In quadrants 1 and 2, MT2 is |
https://en.wikipedia.org/wiki/Gramme%20machine | A Gramme machine, Gramme ring, Gramme magneto, or Gramme dynamo is an electrical generator that produces direct current, named for its Belgian inventor, Zénobe Gramme, and was built as either a dynamo or a magneto. It was the first generator to produce power on a commercial scale for industry. Inspired by a machine invented by Antonio Pacinotti in 1860, Gramme was the developer of a new induced rotor in form of a wire-wrapped ring (Gramme ring) and demonstrated this apparatus to the Academy of Sciences in Paris in 1871. Although popular in 19th century electrical machines, the Gramme winding principle is no longer used since it makes inefficient use of the conductors. The portion of the winding on the interior of the ring cuts no flux and does not contribute to energy conversion in the machine. The winding requires twice the number of turns and twice the number of commutator bars as an equivalent drum-wound armature.
Description
The Gramme machine used a ring armature, with a series of armature coils, wound around a revolving ring of soft iron. The coils are connected in series, and the junction between each pair is connected to a commutator on which two brushes run. Permanent magnets magnetize the soft iron ring, producing a magnetic field which rotates around through the coils in order as the armature turns. This induces a voltage in two of the coils on opposite sides of the armature, which is picked off by the brushes.
Earlier electromagnetic machines passed a magnet near the poles of one or two electromagnets, or rotated coils wound on double-T armatures within a static magnetic field, creating brief spikes or pulses of DC resulting in a transient output of low average power, rather than a constant output of high average power.
With more than a few coils on the Gramme ring armature, the resulting voltage waveform is practically constant, thus producing a near direct current supply. This type of machine needs only electromagnets producing the magnetic field |
https://en.wikipedia.org/wiki/Persin | Persin is a fungicidal toxin present in the avocado. Persin is an oil-soluble compound structurally similar to a fatty acid, and it leaches into the body of the fruit from the seeds.
The relatively low concentrations of persin in the ripe pulp of the avocado fruit is generally considered harmless to humans. Negative effects in humans are primarily in allergic individuals. When persin is consumed by domestic animals through the leaves or bark of the avocado tree, or skins and seeds of the avocado fruit, it is toxic and dangerous.
Pathology
Consumption of the leaves and bark of the avocado tree, or the skin and pit of the avocado fruit have been shown to have the following effects:
In birds, which are particularly sensitive to the avocado toxin, the symptoms are: increased heart rate, myocardial tissue damage, labored breathing, disordered plumage, unrest, weakness, and apathy. High doses cause acute respiratory syndrome (asphyxia), with death approximately 12 to 24 hours after consumption.
Lactating rabbits and mice: non-infectious mastitis and agalactia after consumption of leaves or bark.
Rabbits: cardial arrhythmia, submandibular edema and death after consumption of leaves.
Cows and goats: mastitis, decreased milk production after consumption of leaves or bark.
Horses: clinical effects occur mainly in mares, and includes noninfectious mastitis, as well as occasional gastritis and colic.
Cats, dogs: mild stomach upset may occur, with potential to cause heart damage.
Hares, pigs, rats, sheep, ostriches, chickens, turkeys and fish: symptoms of intoxication similar those described above. The lethal dose is not known; the effect is different depending upon the animal species.
Mice: non-fatal injury to the lactating mammary gland from 60 to 100 mg/kg Persin. Necrosis of myocardial fibres with 100 mg/kg Persin. 200 mg/kg lethal.
Diagnosis
Diagnosis of avocado toxicosis relies on history of exposure and clinical signs. There are no readily available specific tests |
https://en.wikipedia.org/wiki/Chebyshev%20distance | In mathematics, Chebyshev distance (or Tchebychev distance), maximum metric, or L∞ metric is a metric defined on a vector space where the distance between two vectors is the greatest of their differences along any coordinate dimension. It is named after Pafnuty Chebyshev.
It is also known as chessboard distance, since in the game of chess the minimum number of moves needed by a king to go from one square on a chessboard to another equals the Chebyshev distance between the centers of the squares, if the squares have side length one, as represented in 2-D spatial coordinates with axes aligned to the edges of the board. For example, the Chebyshev distance between f6 and e2 equals 4.
Definition
The Chebyshev distance between two vectors or points x and y, with standard coordinates and , respectively, is
This equals the limit of the Lp metrics:
hence it is also known as the L∞ metric.
Mathematically, the Chebyshev distance is a metric induced by the supremum norm or uniform norm. It is an example of an injective metric.
In two dimensions, i.e. plane geometry, if the points p and q have Cartesian coordinates
and , their Chebyshev distance is
Under this metric, a circle of radius r, which is the set of points with Chebyshev distance r from a center point, is a square whose sides have the length 2r and are parallel to the coordinate axes.
On a chessboard, where one is using a discrete Chebyshev distance, rather than a continuous one, the circle of radius r is a square of side lengths 2r, measuring from the centers of squares, and thus each side contains 2r+1 squares; for example, the circle of radius 1 on a chess board is a 3×3 square.
Properties
In one dimension, all Lp metrics are equal – they are just the absolute value of the difference.
The two dimensional Manhattan distance has "circles" i.e. level sets in the form of squares, with sides of length r, oriented at an angle of π/4 (45°) to the coordinate axes, so the planar Chebyshev distance can be viewed |
https://en.wikipedia.org/wiki/Saw%20palmetto%20extract | Saw palmetto extract is an extract of the fruit of the saw palmetto. It is marketed as a dietary supplement that may help with benign prostatic hyperplasia, but there is no clinical evidence that it is effective for this purpose.
Uses and research
Saw palmetto extract is commonly sold as a dietary supplement intended to improve symptoms of benign prostatic hyperplasia (BPH)—also called prostate gland enlargement—which is a common condition among men as they age. An enlarged prostate may cause increased frequency or urgency of urination, difficulty initiating urination, weak urine stream or a stream that stops and starts, dribbling at the end of urination, and inability to completely empty the bladder.
Saw palmetto extract has been studied in clinical trials as a possible treatment for people with prostate cancer and for men with lower urinary tract symptoms associated with BPH. , there is insufficient scientific evidence that saw palmetto extract is effective for treating cancer or BPH and its symptoms.
One 2016 review of clinical studies with a standardized extract of saw palmetto (called Permixon) found that the extract was safe and may be effective for relieving BPH-induced urinary symptoms compared with a placebo.
Folk medicine
Saw palmetto was used in folk medicine to treat coughs or other disorders.
Precautions and contraindications
Children
The use of saw palmetto extract is not recommended in children under 12 years old because it may affect the metabolism of androgen and estrogen hormones.
Pregnancy and lactation
Saw palmetto extract should not be used during pregnancy because it may affect androgen and estrogen metabolism. As there is no rationale for using saw palmetto during pregnancy, it should be avoided when pregnant or while breastfeeding.
PSA test interference
Saw palmetto has been shown to reduce the levels of PSA in the blood, a hormone produced by the prostate and used as a marker by healthcare providers to evaluate the presence of pro |
https://en.wikipedia.org/wiki/Faraday%20constant | In physical chemistry, the Faraday constant (symbol , sometimes stylized as ℱ) is a physical constant defined as the quotient of the total electric charge (q) by the amount (n) of elementary charge carriers in any given sample of matter: Fq/n; it is expressed in units of coulombs per mole (C/mol).
As such, it represents the "molar elementary charge", i.e., the electric charge of one mole of elementary carriers (e.g., protons).
It is named after the English scientist Michael Faraday. Since the 2019 redefinition of SI base units, the Faraday constant has an exactly defined value, the product of the elementary charge (e, in coulombs) and the Avogadro constant (NA, in reciprocal moles):
.
Derivation
The Faraday constant can be thought of as the conversion factor between the mole (used in chemistry) and the coulomb (used in physics and in practical electrical measurements), and is therefore of particular use in electrochemistry. Because 1 mole contains exactly entities, and 1 coulomb contains exactly elementary charges, the Faraday constant is given by the quotient of these two quantities:
.
One common use of the Faraday constant is in electrolysis calculations. One can divide the amount of charge (the current integrated over time) by the Faraday constant in order to find the chemical amount of a substance (in moles) that has been electrolyzed.
The value of was first determined by weighing the amount of silver deposited in an electrochemical reaction in which a measured current was passed for a measured time, and using Faraday's law of electrolysis.
Other common units
96.485 kJ per volt–gram-equivalent
23.061 kcal per volt–gram-equivalent
26.801 A·h/mol
Faraday – a unit of charge
Related to the Faraday constant is the "faraday", a unit of electrical charge. Its use is much less common than of the coulomb, but is sometimes used in electrochemistry. One faraday of charge is the charge of one mole of elementary charges (or of negative one mole of electrons), |
https://en.wikipedia.org/wiki/Spectrum%20of%20a%20theory | In model theory, a branch of mathematical logic, the spectrum of a theory
is given by the number of isomorphism classes of models in various cardinalities. More precisely,
for any complete theory T in a language we write I(T, κ) for the number of models of T (up to isomorphism) of cardinality κ. The spectrum problem is to describe the possible behaviors of I(T, κ) as a function of κ. It has been almost completely solved for the case of a countable theory T.
Early results
In this section T is a countable complete theory and κ is a cardinal.
The Löwenheim–Skolem theorem shows that if I(T,κ) is nonzero for one infinite cardinal then it is nonzero for all of them.
Morley's categoricity theorem was the first main step in solving the spectrum problem: it states that if I(T,κ) is 1 for some uncountable κ then it is 1 for all uncountable κ.
Robert Vaught showed that I(T,ℵ0) cannot be 2. It is easy to find examples where it is any given non-negative integer other than 2. Morley proved that if I(T,ℵ0) is infinite then it must be ℵ0 or ℵ1 or 2ℵ0. It is not known if it can be ℵ1 if the continuum hypothesis is false: this is called the Vaught conjecture and is the main remaining open problem (in 2005) in the theory of the spectrum.
Morley's problem was a conjecture (now a theorem) first proposed by Michael D. Morley that I(T,κ) is nondecreasing in κ for uncountable κ. This was proved by Saharon Shelah. For this, he proved a very deep dichotomy theorem.
Saharon Shelah gave an almost complete solution to the spectrum problem. For a given complete theory T, either I(T,κ) = 2κ for all uncountable cardinals κ, or for all ordinals ξ (See Aleph number and Beth number for an explanation of the notation), which is usually much smaller than the bound in the first case. Roughly speaking this means that either there are the maximum possible number of models in all uncountable cardinalities, or there are only "few" models in all uncountable cardinalities. Shelah also gave a de |
https://en.wikipedia.org/wiki/Integer%20circuit | In computational complexity theory, an integer circuit is a circuit model of computation in which inputs to the circuit are sets of integers and each gate of the circuit computes either a set operation or an arithmetic operation on its input sets.
As an algorithmic problem, the possible questions are to find if a given integer is an element of the output node or if two circuits compute the same set. The decidability is still an open question, but there are results on restriction of those circuits. Finding answers to some questions about this model could serve as a proof to many important mathematical conjectures, like Goldbach's conjecture.
It is a natural extension of the circuits over sets of natural numbers when the considered set contains also negative integers, the definitions, which does not change, will not be repeated on this page. Only the differences will be mentioned.
Complexity of the membership problem
The membership problem is the problem of deciding, given an integer circuit C, an input to the circuit X, and a specific integer n, whether the integer n is in the output of the circuit C when provided with input X. The computational complexity of this problem depends on the type of gates allowed in the circuit C. The table below summarizes the computational complexity of the membership problem for various classes of integer circuits.
Here, MF(O) denotes the classes defined by O-formulae, which are O-circuits with maximal fan-out 1. |
https://en.wikipedia.org/wiki/Prevotella%20intermedia | Prevotella intermedia (formerly Bacteroides intermedius) is a gram-negative, obligate anaerobic pathogenic bacterium involved in periodontal infections, including gingivitis and periodontitis, and often found in acute necrotizing ulcerative gingivitis. It is commonly isolated from dental abscesses, where obligate anaerobes predominate.
P. intermedia is thought to be more prevalent in patients with noma.
P. intermedia use steroid hormones as growth factors, so their numbers are higher in pregnant women. It has also been isolated from women with bacterial vaginosis.
See also
Oral microbiology
List of bacterial vaginosis microbiota |
https://en.wikipedia.org/wiki/Version%206%20Unix | Sixth Edition Unix, also called Version 6 Unix or just V6, was the first version of the Unix operating system to see wide release outside Bell Labs. It was released in May 1975 and, like its direct predecessor, targeted the DEC PDP-11 family of minicomputers. It was superseded by Version 7 Unix in 1978/1979, although V6 systems remained in regular operation until at least 1985.
AT&T Corporation licensed Version 5 Unix to educational institutions only, but licensed Version 6 also to commercial users for $20,000, and it remained the most widely used version into the 1980s. An enhanced V6 was the basis of the first ever commercially sold Unix version, INTERACTIVE's IS/1. Bell's own PWB/UNIX 1.0 was also based on V6, where earlier (unreleased) versions were based on V4 and V5. Whitesmiths produced and marketed a (binary-compatible) V6 clone under the name Idris.
Source code
V6 Unix was released as a distribution including the full source code. Since source code was available and the license was not explicit enough to forbid it, V6 was taken up as a teaching tool, notably by the University of California, Berkeley, Johns Hopkins University and the University of New South Wales (UNSW).
UC Berkeley distributed a set of add-on programs called the First Berkeley Software Distribution or 1BSD, which later became a complete operating system distribution.
UNSW professor John Lions' famous Commentary on UNIX 6th Edition was an edited selection of the main parts of the kernel as implemented for a Digital PDP-11/40, and was the main source of kernel documentation for many early Unix developers. Due to license restrictions on later Unix versions, the book was mainly distributed by samizdat photo-copying.
The source code for the original V6 Unix was later made available as free software under a BSD License from the SCO Group.
Portability
Interdata 7/32
In 1977, Richard Miller and Ross Nealon, working under the supervision of professor Juris Reinfelds at Wollongong University |
https://en.wikipedia.org/wiki/Chaim%20Goodman-Strauss | Chaim Goodman-Strauss (born June 22, 1967 in Austin, Texas) is an American mathematician who works in convex geometry, especially aperiodic tiling. He is on the faculty of the University of Arkansas and currently serves as outreach mathematician for the National Museum of Mathematics. He is co-author with John H. Conway and Heidi Burgiel of The Symmetries of Things, a comprehensive book surveying the mathematical theory of patterns.
Education and career
Goodman-Strauss received both his B.S. (1988) and Ph.D. (1994) in mathematics from the University of Texas at Austin. His doctoral advisor was John Edwin Luecke. He joined the faculty at the University of Arkansas, Fayetteville (UA) in 1994 and served as departmental chair from 2008 to 2015. He held visiting positions at the National Autonomous University of Mexico and Princeton University.
During 1995 he did research at The Geometry Center, a mathematics research and education center at the University of Minnesota, where he investigated aperiodic tilings of the plane.
Goodman-Strauss has been fascinated by patterns and mathematical paradoxes for as long as he can remember. He attended a lecture about the mathematician Georg Cantor when he was 17 and says, "I was already doomed to be a mathematician, but that lecture sealed my fate." He became a mathematics writer and popularizer. From 2004 to 2012, in conjunction with KUAF 91.3 FM, the University of Arkansas NPR affiliate, he presented "The Math Factor," a podcast website dealing with recreational mathematics. He is an admirer of Martin Gardner and is on the advisory council of Gathering 4 Gardner, an organization that celebrates the legacy of the famed mathematics popularizer and Scientific American columnist, and is active in the associated Celebration of Mind events. In 2022 Goodman-Strauss was awarded the National Museum of Mathematics' Rosenthal Prize, which recognizes innovation and inspiration in math teaching.
Aperiodic monotiles
On Mar 20, 2023 Straus |
https://en.wikipedia.org/wiki/Mathematical%20Methods%20of%20Classical%20Mechanics | Mathematical Methods of Classical Mechanics is a textbook by mathematician Vladimir I. Arnold. It was originally written in Russian, and later translated into English by A. Weinstein and K. Vogtmann. It is aimed at graduate students.
Russian original and translations
The original Russian first edition Математические методы классической механики was published in 1974 by Наука. A second edition was published in 1979, and a third in 1989. The book has since been translated into a number of other languages, including French, German, Japanese and Mandarin.
Reviews
The Bulletin of the American Mathematical Society said, "The [book] under review [...] written by a distinguished mathematician [...is one of] the first textbooks [to] successfully to present to students of mathematics and physics, [sic] classical mechanics in a modern setting."
A book review in the journal Celestial Mechanics said, "In summary, the author has succeeded in producing a mathematical synthesis of the science of dynamics. The book is well presented and beautifully translated [...] Arnold's book is pure poetry; one does not simply read it, one enjoys it."
See also
List of textbooks in classical and quantum mechanics |
https://en.wikipedia.org/wiki/SafeNet | SafeNet, Inc. was an information security company based in Belcamp, Maryland, United States, which was acquired in August 2014 by the French security company Gemalto. Gemalto was, in turn, acquired by Thales Group in 2019. The former SafeNet's products include solutions for enterprise authentication, data encryption, and key management. SafeNet's software monetization products are sold under the Thales Sentinel brand.
SafeNet was notably one of the largest suppliers of encryption technology to the United States Government.
On 8 August 2014, Gemalto announced that it had signed a definitive agreement to acquire 100% of the share capital of SafeNet from Vector Capital for US$890 million on a debt free/cash free basis. A subsequent acquisition of Gemalto by French rival Thales Group was completed on 2 April 2019.
History
1983: SafeNet, Inc is founded in 1983 in Timonium, MD as Industrial Resource Engineering by two former NSA engineers, Alan Hastings and technical visionary Douglas Kozlay.
1986: Anthony A. Caputo becomes a silent investor in the company.
1987: Anthony Caputo takes the helm of the company as CEO and changes the name to Information Resource Engineering.
1988: Lawrence Livermore Labs becomes IRE's first major customer. The company moves its operations to White Marsh, MD.
1989: IRE goes public in an IPO initially trading on the OTC pink sheets.
1989: IRE rapidly becomes the leader in banking communications security with seven of the top ten U.S. banks as customers and encryption devices used by SWIFT (global interbank transfer system). An end-to-end encryption system was developed that secured data over an X.25 public network, providing the world's first "virtual private network." Early adopters included the Bank of Montreal and Citibank.
1994: IRE acquires Connective Strategies, Inc., a manufacturer of voice and data ISDN products founded by its CEO, Charles Brown.
October 1995: IRE acquires Swiss crypto manufacturer Gretag Data System |
https://en.wikipedia.org/wiki/Machine | A machine is a physical system using power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolecules, such as molecular machines. Machines can be driven by animals and people, by natural forces such as wind and water, and by chemical, thermal, or electrical power, and include a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors that monitor performance and plan movement, often called mechanical systems.
Renaissance natural philosophers identified six simple machines which were the elementary devices that put a load into motion, and calculated the ratio of output force to input force, known today as mechanical advantage.
Modern machines are complex systems that consist of structural elements, mechanisms and control components and include interfaces for convenient use. Examples include: a wide range of vehicles, such as trains, automobiles, boats and airplanes; appliances in the home and office, including computers, building air handling and water handling systems; as well as farm machinery, machine tools and factory automation systems and robots.
Etymology
The English word machine comes through Middle French from Latin , which in turn derives from the Greek (Doric , Ionic 'contrivance, machine, engine', a derivation from 'means, expedient, remedy'). The word mechanical (Greek: ) comes from the same Greek roots. A wider meaning of 'fabric, structure' is found in classical Latin, but not in Greek usage. This meaning is found in late medieval French, and is adopted from the French into English in the mid-16th century.
In the 17th century, the word machine could also mean a scheme or plot, a meaning now expressed by the derived machination. The modern meaning develops out of specialized application of the term to st |
https://en.wikipedia.org/wiki/Size%E2%80%93weight%20illusion | The size–weight illusion, also known as the Charpentier illusion, is named after the French physician Augustin Charpentier because he was the first to demonstrate the illusion experimentally.
It is also called De Moor's illusion, named after Belgian physician Jean Demoor (1867–1941).
Description
The illusion occurs when a person underestimates the weight of a larger object (e.g. a box) when compared to a smaller object of the same mass. The illusion also occurs when the objects are not lifted against gravity, but accelerated horizontally, so it should be called a size-mass illusion. Similar illusions occurs with differences in material and colour: metal containers feel lighter than wooden containers of the same size and mass, and darker objects feel heavier than brighter objects of the same size and mass. These illusions have all been described as contrast with the expected weight, although the size-weight illusion occurs independent of visual estimates of the volume of material and the illusion does not depend on expectations, but occurs also if visual size information is only provided while already lifting. The expected weight or density can be measured by matching visible and hidden weights, lifted in the same manner. This gives an expected density of about 1.7 for metal canisters and 0.14 for polystyrene blocks. Density expectations may assist in selecting suitable objects to throw.
Explanation
An early explanation of these illusions was that people judge the weight of an object from its appearance and then lift it with a pre-determined force. They expect a larger object to be heavier and therefore lift it with greater force: the larger object is then lifted more easily than the smaller one, causing it to be perceived as lighter. This hypothesis was disproved by an experiment in which two objects of the same mass, same cross section, but different height were placed on observers' supported hands, and produced a passive size–weight illusion. Recent studies ha |
https://en.wikipedia.org/wiki/Coefficient%20of%20variation | In probability theory and statistics, the coefficient of variation (CV), also known as Normalized Root-Mean-Square Deviation (NRMSD), Percent RMS, and relative standard deviation (RSD), is a standardized measure of dispersion of a probability distribution or frequency distribution. It is defined as the ratio of the standard deviation to the mean (or its absolute value, , and often expressed as a percentage ("%RSD"). The CV or RSD is widely used in analytical chemistry to express the precision and repeatability of an assay. It is also commonly used in fields such as engineering or physics when doing quality assurance studies and ANOVA gauge R&R, by economists and investors in economic models, and in psychology/neuroscience.
Definition
The coefficient of variation (CV) is defined as the ratio of the standard deviation to the mean ,
It shows the extent of variability in relation to the mean of the population.
The coefficient of variation should be computed only for data measured on scales that have a meaningful zero (ratio scale) and hence allow relative comparison of two measurements (i.e., division of one measurement by the other). The coefficient of variation may not have any meaning for data on an interval scale. For example, most temperature scales (e.g., Celsius, Fahrenheit etc.) are interval scales with arbitrary zeros, so the computed coefficient of variation would be different depending on the scale used. On the other hand, Kelvin temperature has a meaningful zero, the complete absence of thermal energy, and thus is a ratio scale. In plain language, it is meaningful to say that 20 Kelvin is twice as hot as 10 Kelvin, but only in this scale with a true absolute zero. While a standard deviation (SD) can be measured in Kelvin, Celsius, or Fahrenheit, the value computed is only applicable to that scale. Only the Kelvin scale can be used to compute a valid coefficient of variability.
Measurements that are log-normally distributed exhibit stationary CV; in c |
https://en.wikipedia.org/wiki/Simulation%20for%20Automatic%20Machinery | Simulation for Automatic Machinery or SAM were two unique minicomputers built by the Norwegian Defence Research Establishment (NDRE) in the mid-1960s. SAM 1, built between 1962 and 1964, was the first Norwegian-built programmable computer. It featured 4,096 14-bit words of memory and 14 registers and was used in-house at NDRE. SAM 2 was built between 1966 and 1967 and was used for analysis of satellite imagery at Tromsø Satellite Station. A third-generation computer, it was among the first three in the world to use integrated circuits.
NDRE's first computer had been Lydia which was used for anti-submarine warfare. When it was completed in 1962, the design group led by Yngvar Lundh started working on SAM 1. After it was completed, NDRE convinced the satellite station to procure a Norwegian computer, despite that it had yet to be developed. Key people in the SAM 2 development were Lars Monrad-Krohn, Per Bjørge and Rolf Skår. On the basis of SAM 2 they established Norsk Data and developed the Nord-1 minicomputer.
Development
The first attempts by NDRE to build a computer were made by the mathematics division in the early 1950s. There were two main intended uses: calculation of orbital mechanics for ballistic missiles and for the dimensions for Kjeller Reactor. The background was that NDRE had a keypunch machine, but there were no commercially available digital computers. In 1953 NDRE was offered a digital Ferranti computer via the Norwegian Intelligence Service and the agency thus terminated its own computer development and instead focused on software.
The development of SAM arose in the NDRE's servo division. Led by Karl Holberg, it was working on Terne, an anti-submarine warfare system. The system relied on an analogue electromechanical computer and NDRE saw the possibility of using digital computers instead. Yngvar Lundh wrote his master's thesis in engineering at NDRE in 1957 and then studied at Massachusetts Institute of Technology in the US where he encounter |
https://en.wikipedia.org/wiki/BASIC%20Atom | Basic Atom refers to a line of self-contained microcontrollers from Basic Micro.
Like the Basic stamp, the Basic Atom line is based upon various microchips pre-programmed with an interpreter, making it easy to change "programs", as they are only "data" being interpreted. A compiler converts a high level language into the interpretive "code" which is then loaded in as data, and run.
The product line consists of:
Basic Atom - Basic Stamp 2 compatible devices, claiming faster execution
Basic Atom Nano, a series of pre-programmed chips for those that want to integrate the functionality into other products without adding other boards
Basic Atom Pro, a line of higher capacity devices.
Board-level products, such as for robotic control, etc.
Accessories such as power supplies.
Basic Atom chips may be added to other projects via the familiar Dual in-line package style, or the higher density TQFP.
One small Basic Atom Pro is implemented as a Single in-line package thus taking very little area on a board, at the expense of greater height.
Atoms |
https://en.wikipedia.org/wiki/Heme%20O | Heme O (or haem O) differs from the closely related heme A by having a methyl group at ring position 8 instead of the formyl group. The isoprenoid chain at position 2 is the same.
Heme O, found in the bacterium Escherichia coli, functions in a similar manner to heme A in mammalian oxygen reduction.
See also
Heme |
https://en.wikipedia.org/wiki/Indexation%20of%20contracts | In statistics relating to national economies, the indexation of contracts also called "index linking" and "contract escalation" is a procedure when a contract includes a periodic adjustment to the prices paid for the contract provisions based on the level of a nominated price index. The purpose of indexation is to readjust contracts to account for inflation. In the United States, the consumer price index (CPI), producer price index (PPI) and Employment Cost Index (ECI) are the most frequently used indexes.
See also
Indexation
Purchasing power
Bureau of Labor Statistics |
https://en.wikipedia.org/wiki/Haematopoietic%20system | The haematopoietic system is the system in the body involved in the creation of the cells of blood.
Structure
Stem cells
Haematopoietic stem cells (HSCs) reside in the medulla of the bone (bone marrow) and have the unique ability to give rise to all of the different mature blood cell types and tissues. HSCs are self-renewing cells: when they differentiate, at least some of their daughter cells remain as HSCs, so the pool of stem cells is not depleted. This phenomenon is called asymmetric division. The other daughters of HSCs (myeloid and lymphoid progenitor cells) can follow any of the other differentiation pathways that lead to the production of one or more specific types of blood cell, but cannot renew themselves. The pool of progenitors is heterogeneous and can be divided into two groups; long-term self-renewing HSC and only transiently self-renewing HSC, also called short-terms. This is one of the main vital processes in the body.
Development
In developing embryos, blood formation occurs in aggregates of blood cells in the yolk sac, called blood islands. As development progresses, blood formation occurs in the spleen, liver and lymph nodes. When bone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism. However, maturation, activation, and some proliferation of lymphoid cells occurs in the spleen, thymus, and lymph nodes. In children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.
Function
Haematopoiesis (from Greek αἷμα, "blood" and ποιεῖν "to make"; also hematopoiesis in American English; sometimes also haemopoiesis or hemopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult person, approximately 1011–1012 new blood cells are produced daily in order to maintain steady state levels in the per |
https://en.wikipedia.org/wiki/History%20of%20evolutionary%20thought | Evolutionary thought, the recognition that species change over time and the perceived understanding of how such processes work, has roots in antiquity—in the ideas of the ancient Greeks, Romans, Chinese, Church Fathers as well as in medieval Islamic science. With the beginnings of modern biological taxonomy in the late 17th century, two opposed ideas influenced Western biological thinking: essentialism, the belief that every species has essential characteristics that are unalterable, a concept which had developed from medieval Aristotelian metaphysics, and that fit well with natural theology; and the development of the new anti-Aristotelian approach to modern science: as the Enlightenment progressed, evolutionary cosmology and the mechanical philosophy spread from the physical sciences to natural history. Naturalists began to focus on the variability of species; the emergence of palaeontology with the concept of extinction further undermined static views of nature. In the early 19th century prior to Darwinism, Jean-Baptiste Lamarck (1744–1829) proposed his theory of the transmutation of species, the first fully formed theory of evolution.
In 1858 Charles Darwin and Alfred Russel Wallace published a new evolutionary theory, explained in detail in Darwin's On the Origin of Species (1859). Darwin's theory, originally called descent with modification is known contemporarily as Darwinism or Darwinian theory. Unlike Lamarck, Darwin proposed common descent and a branching tree of life, meaning that two very different species could share a common ancestor. Darwin based his theory on the idea of natural selection: it synthesized a broad range of evidence from animal husbandry, biogeography, geology, morphology, and embryology. Debate over Darwin's work led to the rapid acceptance of the general concept of evolution, but the specific mechanism he proposed, natural selection, was not widely accepted until it was revived by developments in biology that occurred during the 19 |
https://en.wikipedia.org/wiki/Cruciate%20anastomosis | The cruciate anastomosis is a circulatory anastomosis in the upper thigh formed by the inferior gluteal artery, the lateral and medial circumflex femoral arteries, the first perforating artery of the deep femoral artery, and the anastomotic branch of the posterior branch of the obturator artery.
The cruciate anastomosis is clinically relevant because if there is a blockage between the femoral artery and external iliac artery, blood can reach the popliteal artery by means of the anastomosis. The route of blood is through the internal iliac, to the inferior gluteal artery, to a perforating branch of the deep femoral artery, to the lateral circumflex femoral artery, then to its descending branch into the superior lateral genicular artery and thus into the popliteal artery.
Structure
The cruciate anastomosis is so-called because it resembles a cross.
Its four components are:
Inferior gluteal artery
Transverse branches of the lateral circumflex femoral artery and the medial circumflex femoral artery
Ascending branch of the first perforating artery from the deep femoral artery
See also
Trochanteric anastomosis |
https://en.wikipedia.org/wiki/Version%20vector | A version vector is a mechanism for tracking changes to data in a distributed system, where multiple agents might update the data at different times. The version vector allows the participants to determine if one update preceded another (happened-before), followed it, or if the two updates happened concurrently (and therefore might conflict with each other). In this way, version vectors enable causality tracking among data replicas and are a basic mechanism for optimistic replication. In mathematical terms, the version vector generates a preorder that tracks the events that precede, and may therefore influence, later updates.
Version vectors maintain state identical to that in a vector clock, but the update rules differ slightly; in this example, replicas can either experience local updates (e.g., the user editing a file on the local node), or can synchronize with another replica:
Initially all vector counters are zero.
Each time a replica experiences a local update event, it increments its own counter in the vector by one.
Each time two replicas and synchronize, they both set the elements in their copy of the vector to the maximum of the element across both counters: . After synchronization, the two replicas have identical version vectors.
Pairs of replicas, , , can be compared by inspecting their version vectors and determined to be either: identical (), concurrent (), or ordered ( or ). The ordered relation is defined as: Vector if and only if every element of is less than or equal to its corresponding element in , and at least one of the elements is strictly less than. If neither or , but the vectors are not identical, then the two vectors must be concurrent.
Version vectors or variants are used to track updates in many distributed file systems, such as Coda (file system) and Ficus, and are the main data structure behind optimistic replication.
Other mechanisms
Hash Histories avoid the use of counters by keeping a set of hashes of each upd |
https://en.wikipedia.org/wiki/Radium%20dial | Radium dials are watch, clock and other instrument dials painted with luminous paint containing radium-226 to produce radioluminescence. Radium dials were produced throughout most of the 20th century before being replaced by safer tritium-based luminous material in the 1970s and finally by non-toxic, non-radioactive strontium aluminate–based photoluminescent material from the middle 1990s.
History
Radium was discovered by Marie and Pierre Curie in 1898 and was soon combined with paint to make luminescent paint, which was applied to clocks, airplane instruments, and the like, to be able to read them in the dark.
In 1914, Dr. Sabin Arnold von Sochocky and Dr. George S. Willis founded the Radium Luminous Material Corporation. The company made luminescent paint. The company later changed its name to the United States Radium Corporation. The use of radium to provide luminescence for hands and indices on watches soon followed.
The Ingersoll Watch division of the Waterbury Clock Company, a nationally-known maker of low-cost pocket and wristwatches, was a leading popularizer of the use of radium for watch hands and indices through the introduction of their "Radiolite" watches in 1916. The Radiolite series, made in various sizes and models, became a signature of the Connecticut-based company.
Radium dials were typically painted by young women, who used to 'point' their brushes by licking and shaping the bristles prior to painting the fine lines and numbers on the dials. This practice resulted in the ingestion of radium, which caused serious jaw-bone degeneration and malignancy and other dental diseases. The disease, radium-induced osteonecrosis, was recognized as an occupational disease in 1925 after a group of radium painters, known as the Radium Girls, from the United States Radium Corporation sued. By 1930, all dial painters stopped pointing their brushes by mouth. Stopping this practice drastically reduced the amount of radium ingested and therefore, the incidence o |
https://en.wikipedia.org/wiki/Fr%C3%A9chet%20inequalities | In probabilistic logic, the Fréchet inequalities, also known as the Boole–Fréchet inequalities, are rules implicit in the work of George Boole and explicitly derived by Maurice Fréchet that govern the combination of probabilities about logical propositions or events logically linked together in conjunctions (AND operations) or disjunctions (OR operations) as in Boolean expressions or fault or event trees common in risk assessments, engineering design and artificial intelligence. These inequalities can be considered rules about how to bound calculations involving probabilities without assuming independence or, indeed, without making any dependence assumptions whatsoever. The Fréchet inequalities are closely related to the Boole–Bonferroni–Fréchet inequalities, and to Fréchet bounds.
If are logical propositions or events, the Fréchet inequalities are
Probability of a logical conjunction ()
Probability of a logical disjunction ()
where P( ) denotes the probability of an event or proposition. In the case where there are only two events, say A and B, the inequalities reduce to
Probability of a logical conjunction ()
Probability of a logical disjunction ()
The inequalities bound the probabilities of the two kinds of joint events given the probabilities of the individual events. For example, if A is "has lung cancer", and B is "has mesothelioma", then A & B is "has both lung cancer and mesothelioma", and A ∨ B is "has lung cancer or mesothelioma or both diseases", and the inequalities relate the risks of these events.
Note that logical conjunctions are denoted in various ways in different fields, including AND, &, ∧ and graphical AND-gates. Logical disjunctions are likewise denoted in various ways, including OR, |, ∨, and graphical OR-gates. If events are taken to be sets rather than logical propositions, the set-theoretic versions of the Fréchet inequalities are
Probability of an intersection of events
Probability of a union of events
Numerical example |
https://en.wikipedia.org/wiki/Allistatin | Allistatin is the collective name for two chemicals, allistatin I and allistatin II, which are found in garlic. It is a sulfur-free chemical and plays an active role within garlic. It is most likely a flavonoid.
There is no experimental evidence of the structure of allistatin; some studies claim it is similar to cyanidin, while others found it shared similarities with garlicin (but not allicin). |
https://en.wikipedia.org/wiki/Ediacaran%20biota | The Ediacaran (; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (). These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, . This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate.
The organisms of the Ediacaran Period first appeared around and flourished until the cusp of the Cambrian , when the characteristic communities of fossils vanished. A diverse Ediacaran community was discovered in 1995 in Sonora, Mexico, and is approximately 555 million years in age, roughly coeval with Ediacaran fossils of the Ediacara Hills in South Australia and the White Sea on the coast of Russia. While rare fossils that may represent survivors have been found as late as the Middle Cambrian (510–500 Mya), the earlier fossil communities disappear from the record at the end of the Ediacaran leaving only curious fragments of once-thriving ecosystems. Multiple hypotheses exist to explain the disappearance of this biota, including preservation bias, a changing environment, the advent of predators and compe |
https://en.wikipedia.org/wiki/Rakuten%20Rewards | Rakuten Rewards (), formerly known as Ebates, is a cash-back and shopping rewards company. Its revenue comes from affiliate network links. Members of the site click through affiliate links before shopping at a retailer's site. Once the member makes a purchase, Rakuten Rewards receives an affiliate commission from the retailer which is then shared with the member. The company publishes links both on its website and through a browser extension as well as a mobile app.
History
Rakuten Rewards was founded as Ebates in 1998 in Menlo Park, California, by two former deputy district attorneys, Alessandro Isolani and Paul Wasserman. Funded by the venture capital firm Foundation Capital, Ebates.com was launched on 3 May 1999, offering up to 25% cash back from about 40 online retailers.
In September 2014, Ebates was acquired by the Japanese e-commerce company Rakuten for US$1 billion. In 2019, the Ebates brand was phased out and replaced with Rakuten Rewards.
Acquisitions
Services/tools
Logos |
https://en.wikipedia.org/wiki/Antiresonance | In the physics of coupled oscillators, antiresonance, by analogy with resonance, is a pronounced minimum in the amplitude of an oscillator at a particular frequency, accompanied by a large, abrupt shift in its oscillation phase. Such frequencies are known as the system's antiresonant frequencies, and at these frequencies the oscillation amplitude can drop to almost zero. Antiresonances are caused by destructive interference, for example between an external driving force and interaction with another oscillator.
Antiresonances can occur in all types of coupled oscillator systems, including mechanical, acoustical, electromagnetic, and quantum systems. They have important applications in the characterization of complicated coupled systems.
The term antiresonance is used in electrical engineering for a form of resonance in a single oscillator with similar effects.
Antiresonance in electrical engineering
In electrical engineering, antiresonance is the condition for which the reactance vanishes and the impedance of an electrical circuit is very high, approaching infinity.
In an electric circuit consisting of a capacitor and an inductor in parallel, antiresonance occurs when the alternating current line voltage and the resultant current are in phase. Under these conditions the line current is very small because of the high electrical impedance of the parallel circuit at antiresonance. The branch currents are almost equal in magnitude and opposite in phase.
Antiresonance in coupled oscillators
The simplest system in which antiresonance arises is a system of coupled harmonic oscillators, for example pendula or RLC circuits.
Consider two harmonic oscillators coupled together with strength and with one oscillator driven by an oscillating external force . The situation is described by the coupled ordinary differential equations
where the represent the resonance frequencies of the two oscillators and the their damping rates. Changing variables to the complex parameter |
https://en.wikipedia.org/wiki/Trajectory%20%28fluid%20mechanics%29 | In fluid mechanics, meteorology and oceanography, a trajectory traces the motion of a single point, often called a parcel, in the flow.
Trajectories are useful for tracking atmospheric contaminants, such as smoke plumes, and as constituents to Lagrangian simulations, such as contour advection or semi-Lagrangian schemes.
Suppose we have a time-varying flow field, . The motion of a fluid parcel, or trajectory, is given by the following system of ordinary differential equations:
While the equation looks simple, there are at least three concerns when attempting to solve it numerically. The first is the integration scheme. This is typically a Runge-Kutta, although others can be useful as well, such as a leapfrog. The second is the method of determining the velocity vector, at a given position, , and time, t. Normally, it is not known at all positions and times, therefore some method of interpolation is required. If the velocities are gridded in space and time, then bilinear, trilinear or higher-dimensional linear interpolation is appropriate. Bicubic, tricubic, etc., interpolation is used as well, but is probably not worth the extra computational overhead.
Velocity fields can be determined by measurement, e.g. from weather balloons, from numerical models or especially from a combination of the two, e.g. assimilation models.
The final concern is metric corrections. These are necessary for geophysical fluid flows on a spherical Earth. The differential equations for tracing a two-dimensional, atmospheric trajectory in longitude-latitude coordinates are as follows:
where, and are, respectively, the longitude and latitude in radians, r is the radius of the Earth, u is the zonal wind and v is the meridional wind.
One problem with this formulation is the polar singularity: notice how the denominator in the first equation goes to zero when the latitude is 90 degrees—plus or minus. One means of overcoming this is to use a locally Cartesian coordinate system close |
https://en.wikipedia.org/wiki/U.S.-Vietnam%20Dialogue%20Group%20on%20Agent%20Orange/Dioxin | The U.S.-Vietnam Dialogue Group on Agent Orange/Dioxin was formally established in February 2007 as an initiative of prominent private citizens, scientists and policy-makers on both the Vietnamese and US sides, working on issues that the two countries’ governments have found difficult to address. It is not an implementing agency nor a fundraising organization. Its role has been to call attention to the need for five key actions to be undertaken in a humanitarian spirit: to establish treatment and education centers for Vietnamese with disabilities; cooperate with the U.S. and Vietnamese governments to contain and clean up dioxin, beginning at three priority airport "hot spots"; set up a modern dioxin testing laboratory in Vietnam; foster programs for training of trainers in restoration and management of damaged landscapes; and educate the U.S. public on the issues. Leading the Vietnamese side is Ambassador Ngo Quang Xuan, vice chair of the Vietnamese National Assembly's Foreign Affairs Committee, and leading the U.S. side is Walter Isaacson, president and CEO of the Aspen Institute. The convener of the group is Susan Berresford, former President of the Ford Foundation.
Additional members include: Christine Todd Whitman, President, Whitman Strategy Group; William Mayer, President & CEO, Park Avenue Equity Partners; Mary Dolan-Hogrefe, Vice President and Senior Advisor, National Organization on Disability; Dr. Vaughan Turekian, Chief International Officer, American Association for the Advancement of Science; Professor Vo Quy, Center for Natural Resources & Environmental Studies, Vietnam National University, Ho Chi Minh City; Dr. Nguyen Thi Ngoc Phuong, Chief, Obstetrics & Gynecology, Medical University of Ho Chi Minh City; Do Hoang Long, Director, People to People Relations Department, Party External Relations Committee; and Lt. General Phung Khac Dang, Vice President, Vietnam Veterans Association.
On June 16, 2010, members of the U.S.-Vietnam Dialogue Group on Agent |
https://en.wikipedia.org/wiki/External%20sphincter%20muscle%20of%20female%20urethra | The external sphincter muscle of female urethra is a muscle which controls urination in females. The muscle fibers arise on either side from the margin of the inferior ramus of the pubis. They are directed across the pubic arch in front of the urethra, and pass around it to blend with the muscular fibers of the opposite side, between the urethra and vagina.
The term "urethrovaginal sphincter" ("sphincter urethrovaginalis") is sometimes used to describe the component adjacent to the vagina.
The "compressor urethrae" is also considered a distinct, adjacent muscle by some sources,
Function
The muscle helps maintain continence of urine along with the internal urethral sphincter which is under control of the autonomic nervous system. The external sphincter muscle prevents urine leakage as the muscle is tonically contracted via somatic fibers that originate in Onuf's nucleus and pass through sacral spinal nerves S2-S4 then the pudendal nerve to synapse on the muscle.
Voiding urine begins with voluntary relaxation of the external urethral sphincter. This is facilitated by inhibition of the somatic neurons in Onuf's nucleus via signals arising in the pontine micturition center and traveling through the descending reticulospinal tracts.
See also
External sphincter muscle of male urethra
Internal urethral sphincter
Levator ani |
https://en.wikipedia.org/wiki/Marine%20biogeochemical%20cycles | Marine biogeochemical cycles are biogeochemical cycles that occur within marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. These biogeochemical cycles are the pathways chemical substances and elements move through within the marine environment. In addition, substances and elements can be imported into or exported from the marine environment. These imports and exports can occur as exchanges with the atmosphere above, the ocean floor below, or as runoff from the land.
There are biogeochemical cycles for the elements calcium, carbon, hydrogen, mercury, nitrogen, oxygen, phosphorus, selenium, and sulfur; molecular cycles for water and silica; macroscopic cycles such as the rock cycle; as well as human-induced cycles for synthetic compounds such as polychlorinated biphenyl (PCB). In some cycles there are reservoirs where a substance can be stored for a long time. The cycling of these elements is interconnected.
Marine organisms, and particularly marine microorganisms are crucial for the functioning of many of these cycles. The forces driving biogeochemical cycles include metabolic processes within organisms, geological processes involving the earth's mantle, as well as chemical reactions among the substances themselves, which is why these are called biogeochemical cycles. While chemical substances can be broken down and recombined, the chemical elements themselves can be neither created nor destroyed by these forces, so apart from some losses to and gains from outer space, elements are recycled or stored (sequestered) somewhere on or within the planet.
Overview
Energy flows directionally through ecosystems, entering as sunlight (or inorganic molecules for chemoautotrophs) and leaving as heat during the many transfers between trophic levels. However, the matter that makes up living organisms is conserved and recycled. The six most common elements associated with organic molecules—carbon, nitrogen, hydrogen, oxy |
https://en.wikipedia.org/wiki/Timing%20mark | A timing mark is an indicator used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel. These have the largest radius rotating at crankshaft speed and therefore are the place where marks at one degree intervals will be farthest apart.
On older engines it is common to set the ignition timing using a timing light, which flashes in time with the ignition system (and hence engine rotation). Shining the light on the timing marks makes them appear stationary due to the stroboscopic effect. The ignition timing can then be adjusted to fire at the correct point in the engine's rotation, typically a few degrees before top dead centre and advancing with increasing engine speed. The timing can be adjusted by loosening and slightly rotating the distributor in its seat.
Modern engines usually use a crank sensor directly connected to the engine management system.
The term can also be used to describe the tick marks along the length of an optical mark recognition sheet, used to confirm the location of the sheet as it passes through the reader. See, for example, U.S. Patent 3,218,439 (filed 1964, granted 1965), which refers to a timing track down the left side of the form, and U.S. Patent 3,267,258 (filed 1963, granted 1966), which refers to a column of timing marks on the right side of the form.
The term can also be used to describe the timing patterns used in some barcodes, such as PostBar, Data Matrix, Aztec Code, etc. |
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