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🔗 Physics 🔗 Skepticism

Polywater was a hypothesized polymerized form of water that was the subject of much scientific controversy during the late 1960s. By 1969 the popular press had taken notice and sparked fears of a "polywater gap" in the US.

Increased press attention also brought with it increased scientific attention, and as early as 1970 doubts about its authenticity were being circulated. By 1973 it was found to be illusory, being just water with any number of common organic compounds contaminating it.

Today, polywater is best known as an example of pathological science.

🔗 United States 🔗 Mathematics 🔗 Education 🔗 United States/Massachusetts 🔗 Higher Education

Math 55 is a two-semester long first-year undergraduate mathematics course at Harvard University, founded by Lynn Loomis and Shlomo Sternberg. The official titles of the course are Honors Abstract Algebra (Math 55a) and Honors Real and Complex Analysis (Math 55b). Previously, the official title was Honors Advanced Calculus and Linear Algebra.

🔗 United States 🔗 Biography 🔗 Women's History 🔗 Christianity 🔗 Gender Studies 🔗 United States/Rhode Island 🔗 Christianity/Religious Society of Friends (Quakers)

The Public Universal Friend (born Jemima Wilkinson; November 29, 1752 – July 1, 1819) was an American preacher born in Cumberland, Rhode Island, to Quaker parents. After suffering a severe illness in 1776, the Friend claimed to have died and been reanimated as a genderless evangelist named the Public Universal Friend, and afterward shunned both birth name and gendered pronouns. In androgynous clothes, the Friend preached throughout the northeastern United States, attracting many followers who became the Society of Universal Friends.

The Public Universal Friend's theology was broadly similar to that of most Quakers. The Friend stressed free will, opposed slavery, and supported sexual abstinence. The most committed members of the Society of Universal Friends were a group of unmarried women who took leading roles in their households and community. In the 1790s, members of the Society acquired land in Western New York where they formed the township of Jerusalem near Penn Yan, New York. The Society of Universal Friends ceased to exist by the 1860s. Many writers have portrayed the Friend as a woman, and either a manipulative fraudster, or a pioneer for women's rights; others have viewed the preacher as transgender or non-binary and a figure in trans history.

🔗 Computing

Constraint logic programming is a form of constraint programming, in which logic programming is extended to include concepts from constraint satisfaction. A constraint logic program is a logic program that contains constraints in the body of clauses. An example of a clause including a constraint is A(X,Y) :- X+Y>0, B(X), C(Y). In this clause, X+Y>0 is a constraint; A(X,Y), B(X), and C(Y) are literals as in regular logic programming. This clause states one condition under which the statement A(X,Y) holds: X+Y is greater than zero and both B(X) and C(Y) are true.

As in regular logic programming, programs are queried about the provability of a goal, which may contain constraints in addition to literals. A proof for a goal is composed of clauses whose bodies are satisfiable constraints and literals that can in turn be proved using other clauses. Execution is performed by an interpreter, which starts from the goal and recursively scans the clauses trying to prove the goal. Constraints encountered during this scan are placed in a set called constraint store. If this set is found out to be unsatisfiable, the interpreter backtracks, trying to use other clauses for proving the goal. In practice, satisfiability of the constraint store may be checked using an incomplete algorithm, which does not always detect inconsistency.

🔗 India 🔗 Organizations 🔗 India/Uttar Pradesh

The Uttar Pradesh Association of Dead People (Hindi: उत्तर प्रदेश मृतक संघ, Uttar Pradesh Mritak Sangh) is an Indian pressure group based in Azamgarh, Uttar Pradesh that seeks to reclaim the legal rights of those falsely listed by the Uttar Pradesh State government as being dead.

In the overcrowded regions of Uttar Pradesh, many have resorted to bribing officials to have the owner of a plot of land declared deceased and the title transferred to their ownership. The process to undo this is long, arduous, as well as often inefficient and corrupt. The Association seeks to reverse the declarations, call attention to the problem and prevent others from being exploited in similar fashion.

The founder and president is Lal Bihari, who was "dead" from 1976 to 1994 and used the word Mritak (Hindi: मृतक, transl. Dead) in his name during the period.

After being inspired by the story of Bihari, Indian film director Satish Kaushik made a movie Kaagaz, starring Pankaj Tripathi, based on his life. It was released on ZEE5 on 7 January 2021.

🔗 Mathematics

Fractional calculus is a branch of mathematical analysis that studies the several different possibilities of defining real number powers or complex number powers of the differentiation operator D

${\displaystyle Df(x)={\frac {d}{dx}}f(x)\,,}$

and of the integration operator J

${\displaystyle Jf(x)=\int _{0}^{x}f(s)\,ds\,,}$

and developing a calculus for such operators generalizing the classical one.

In this context, the term powers refers to iterative application of a linear operator D to a function f, that is, repeatedly composing D with itself, as in ${\displaystyle D^{2}(f)=(D\circ D)(f)=D(D(f))}$.

For example, one may ask for a meaningful interpretation of:

${\displaystyle {\sqrt {D}}=D^{\frac {1}{2}}}$

as an analogue of the functional square root for the differentiation operator, that is, an expression for some linear operator that when applied twice to any function will have the same effect as differentiation. More generally, one can look at the question of defining a linear functional

${\displaystyle D^{a}}$

for every real-number a in such a way that, when a takes an integer value n ∈ ℤ, it coincides with the usual n-fold differentiation D if n > 0, and with the −nth power of J when n < 0.

One of the motivations behind the introduction and study of these sorts of extensions of the differentiation operator D is that the sets of operator powers { D^a |a ∈ ℝ } defined in this way are continuous semigroups with parameter a, of which the original discrete semigroup of { Dⁿ | n ∈ ℤ } for integer n is a denumerable subgroup: since continuous semigroups have a well developed mathematical theory, they can be applied to other branches of mathematics.

Fractional differential equations, also known as extraordinary differential equations, are a generalization of differential equations through the application of fractional calculus.

🔗 Physics 🔗 Philosophy 🔗 Skepticism 🔗 History of Science 🔗 Science

Some of the major unsolved problems in physics are theoretical, meaning that existing theories seem incapable of explaining a certain observed phenomenon or experimental result. The others are experimental, meaning that there is a difficulty in creating an experiment to test a proposed theory or investigate a phenomenon in greater detail.

There are still some deficiencies in the Standard Model of physics, such as the origin of mass, the strong CP problem, neutrino mass, matter–antimatter asymmetry, and the nature of dark matter and dark energy. Another problem lies within the mathematical framework of the Standard Model itself—the Standard Model is inconsistent with that of general relativity, to the point that one or both theories break down under certain conditions (for example within known spacetime singularities like the Big Bang and the centers of black holes beyond the event horizon).

🔗 Technology 🔗 Electronics 🔗 Engineering 🔗 Industrial design

Muntzing is the practice and technique of reducing the components inside an electronic appliance to the minimum required for it to sufficiently function in most operating conditions, reducing design margins above minimum requirements toward zero. The term is named after the man who invented it, Earl "Madman" Muntz, a car and electronics salesman, who was not formally educated or trained in any science or engineering discipline.

In the 1940s and 1950s, television receivers were relatively new to the consumer market, and were more complex pieces of equipment than the radios which were then in popular use. TVs often contained upwards of 30 vacuum tubes, as well as transformers, rheostats, and other electronics. The consequence of high cost was high sales pricing, limiting potential for high-volume sales. Muntz expressed suspicion of complexity in circuit designs, and determined through simple trial and error that he could remove a significant number of electronic components from a circuit design and still end up with a monochrome TV that worked sufficiently well in urban areas, close to transmission towers where the broadcast signal was strong. He carried a pair of wire clippers, and when he felt that one of his builders was overengineering a circuit, he would begin snipping out some of the electronics components. When the TV stopped functioning, he would have the technician reinsert the last removed part. He would repeat the snipping in other portions of the circuit until he was satisfied in his simplification efforts, and then leave the TV as it was without further testing in more adverse conditions for signal reception.

As a result, he reduced his costs and increased his profits at the expense of poorer performance at locations more distant from urban centers. He reasoned that population density was higher in and near the urban centers where the TVs would work, and lower further out where the TVs would not work, so the Muntz TVs were adequate for a very large fraction of his customers. And for those further out, where the Muntz TVs did not work, those could be returned at the customer's additional effort and expense, and not Muntz's. He focused less resources in the product, intentionally accepting bare minimum performance quality, and focused more resources on advertising and sales promotions.

🔗 Television

Mechanical television or mechanical scan television is a television system that relies on a mechanical scanning device, such as a rotating disk with holes in it or a rotating mirror, to scan the scene and generate the video signal, and a similar mechanical device at the receiver to display the picture. This contrasts with modern television technology, which uses electronic scanning methods, for example electron beams in cathode ray tube (CRT) televisions, and liquid-crystal displays (LCD), to create and display the picture.

Mechanical-scanning methods were used in the earliest experimental television systems in the 1920s and 1930s. One of the first experimental wireless television transmissions was by John Logie Baird on November 25, 1925, in London. By 1928 many radio stations were broadcasting experimental television programs using mechanical systems. However the technology never produced images of sufficient quality to become popular with the public. Mechanical-scan systems were largely superseded by electronic-scan technology in the mid-1930s, which was used in the first commercially successful television broadcasts which began in the late 1930s in Great Britain.

A mechanical television receiver is also called a televisor in some countries.

🔗 Canada 🔗 Minnesota 🔗 Canada/Geography of Canada 🔗 National Register of Historic Places

The northwesternmost point of the Lake of the Woods was a critical landmark for the boundary between U.S. territory and the British possessions to the north. This point was referred to in the Treaty of Paris in 1783 and in later treaties including the Treaty of 1818. This point lies at the corner of the Northwest Angle of Minnesota and is thus the northernmost point in the lower 48 United States. After Canadian Confederation, the point became the basis for the border between Manitoba and Ontario.

The "northwesternmost point" of the lake had not yet been identified when it was referenced in treaties defining the border between the US and Britain; it was simply an easily described abstraction based on a large landmark. The best maps at the time of the original negotiation depicted the lake as a simple oval. However, although the southern portion of the lake is easily mapped, to the north it becomes a complex tangle of bays, peninsulas, and islands, with many adjacent bodies of water separated or connected by narrow isthmuses or straits. An 1822 survey crew declared the referenced point impossible to determine. In 1824, British explorer David Thompson was hired to identify it. Thompson mapped the lake and found four possibilities, but did not conclusively declare one location.

In 1825, German astronomer in British service Dr. Johann Ludwig Tiarks surveyed the lake. Tiarks identified two possibilities for the northwesternmost point on the lake, based on Thompson's maps: the Angle Inlet and Rat Portage. To determine which point was the most northwestern, he drew a line from each point in the southwest-northeast direction. If the line intersected the lake at any point, it was not the most northwestern point, as shown in the example diagram here. Tiarks determined that the only such line that did not intersect the lake was at the edge of a pond on the Angle Inlet. (A 1940 academic study documents this point as being in the immediate vicinity of 49°23′51.324″N 95°9′12.20783″W (NAD83).)

Under the 1783 treaty, the international border would have run due west from this point to the Mississippi River. As this was determined to be geographically impossible (the Mississippi begins further south), under the 1818 treaty the international border instead ran from the point determined by Tiarks, to the 49th parallel. (It was not known at the time whether that was to the north or – in fact – the south.) From there it ran due west to the Rocky Mountains (and later, the Pacific coast).

Tiarks' point, however, created problems, because the 1818 treaty called for the border to run directly north–south from it. South of that point, the channel of the Northwest Angle Inlet meandered east and west, crossing the border five times, thereby creating two small enclaves of water areas totaling two and a half acres that belonged to the United States but were surrounded by Canadian waters. A 1925 treaty addressed this by adopting the southernmost of the points where the channel and the border intersected – approximately 5,000 ft (1,500 m) south of Tiarks' point – as the new "northwesternmost point". The new northwesternmost point thus became 49°23′4.14″N 95°9′11.34″W, based on the NAD27 datum, which is equivalent to 49°23′4.12373″N 95°9′12.20783″W under the modern NAD83 datum.