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🔗 History of Science 🔗 Sweden

Ytterby (Swedish pronunciation: [ˈʏ̂tːɛrˌbyː]) is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes.

The Swedish name of the village translates literally into "outer village". Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium (Tb), erbium (Er), and ytterbium (Yb) are all named after Ytterby, and the elements holmium (Ho), scandium (Sc), thulium (Tm), tantalum (Ta), and gadolinium (Gd) were also first discovered there.

Local roads connect Ytterby to county road 274 and hence the mainland. Except for the winter months, passenger ships of the Waxholmsbolaget call at a pier in Ytterby, providing a connection to Vaxholm town and Stockholm. Ytterby is as well served by several local bus lines of the north east SL district, connecting the area directly to Stockholms Östra station.

🔗 United States 🔗 California 🔗 India 🔗 Pakistan 🔗 Ethnic groups 🔗 United States/Asian Americans 🔗 California/Southern California 🔗 United States/Mexican-Americans

The Punjabi Mexican American community, the majority of which is localized to Yuba City, California, is a distinctive ethnicity holding its roots in a migration pattern that occurred almost a century ago. The first meeting of these cultures occurred in the Imperial and Central Valleys in 1907, near the largest irrigation system in the Western Hemisphere.

🔗 Food and drink 🔗 Guild of Copy Editors 🔗 Food and drink/Cheeses

Pizza cheese encompasses several varieties and types of cheeses and dairy products that are designed and manufactured for use specifically on pizza. These include processed and modified cheese such as mozzarella-like processed cheeses and mozzarella variants. The term can also refer to any type of cheese suitable for use on pizza. The most popular cheeses used in the preparation of pizza are mozzarella (accounting for about 30%), provolone, cheddar and Parmesan. Emmental, Romano and ricotta are often used as toppings, and processed pizza cheeses manufactured specifically for pizza are mass-produced. Some mass-produced pizza cheeses are frozen after manufacturing and shipped frozen.

Processed pizza cheese is manufactured to produce optimal qualities in browning, melting, stretchiness and fat and moisture content. Several studies and experiments have analyzed the impact of vegetable oil, manufacturing and culture processes, denatured whey proteins and other changes to create ideal and economical pizza cheeses. In 1997, it was estimated that annual production of pizza cheese products was 2 billion pounds in the United States and 200 million pounds in Europe, and in 2000 demand for the product in Europe was increasing by 8% per year. The trend of steadily-increasing production and consumption of mozzarella and pizza cheese continued into the first decade of the 21st century in the United States.

🔗 Climate change 🔗 Environment 🔗 Volcanoes

The 1808 mystery eruption was a large volcanic eruption conjectured to have taken place in late 1808, possibly in the southwest Pacific. A VEI-6 eruption, comparable to the 1883 eruption of Krakatoa, is suspected of having contributed to a period of global cooling that lasted for years, analogous to how the 1815 eruption of Mount Tambora (VEI-7) led to the Year Without a Summer in 1816.

🔗 Biology 🔗 Skepticism 🔗 Solar System

Panspermia (from Ancient Greek πᾶν (pan), meaning 'all', and σπέρμα (sperma), meaning 'seed') is the hypothesis that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, planetoids, and also by spacecraft carrying unintended contamination by microorganisms. Distribution may have occurred spanning galaxies, and so may not be restricted to the limited scale of solar systems.

Panspermia hypotheses propose (for example) that microscopic life-forms that can survive the effects of space (such as extremophiles) can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. Under certain ideal impact circumstances (into a body of water, for example), and ideal conditions on a new planet's surfaces, it is possible that the surviving organisms could become active and begin to colonize their new environment. At least one report finds that endospores from a type of Bacillus bacteria found in Morocco can survive being heated to 420 °C (788 °F), making the argument for Panspermia even stronger. Panspermia studies concentrate not on how life began, but on methods that may distribute it in the Universe.

Pseudo-panspermia (sometimes called "soft panspermia" or "molecular panspermia") argues that the pre-biotic organic building-blocks of life originated in space, became incorporated in the solar nebula from which planets condensed, and were further—and continuously—distributed to planetary surfaces where life then emerged (abiogenesis). From the early 1970s, it started to become evident that interstellar dust included a large component of organic molecules. Interstellar molecules are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. The dust plays a critical role in shielding the molecules from the ionizing effect of ultraviolet radiation emitted by stars.

The chemistry leading to life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the Universe was only 10 to 17 million years old. Though the presence of life is confirmed only on the Earth, some scientists think that extraterrestrial life is not only plausible, but probable or inevitable. Probes and instruments have started examining other planets and moons in the Solar System and in other planetary systems for evidence of having once supported simple life, and projects such as SETI attempt to detect radio transmissions from possible extraterrestrial civilizations.

🔗 Biography 🔗 France 🔗 Physics 🔗 Skepticism 🔗 Physics/Biographies 🔗 Physics/Publications

The Bogdanov affair was an academic dispute regarding the legitimacy of a series of theoretical physics papers written by French twins Igor and Grichka Bogdanov (alternately spelt Bogdanoff). These papers were published in reputable scientific journals, and were alleged by their authors to culminate in a proposed theory for describing what occurred at and before the Big Bang.

The controversy began in 2002, with an allegation that the twins, celebrities in France for hosting science-themed TV shows, had obtained PhDs with nonsensical work. Rumours spread on Usenet newsgroups that their work was a deliberate hoax intended to target weaknesses in the peer review system that physics journals use to select papers for publication. While the Bogdanov brothers continued to defend the veracity of their work, the debate over whether or not it represented a contribution to physics spread from Usenet to many other Internet forums, eventually receiving coverage in the mainstream media. A Centre national de la recherche scientifique (CNRS) internal report later concluded that their theses had no scientific value.

The incident prompted criticism of the Bogdanovs' approach to science popularization, led to multiple lawsuits, and provoked reflection among physicists as to how and why the peer review system can fail.

🔗 Mathematics 🔗 Physics

Shor's algorithm is a polynomial-time quantum computer algorithm for integer factorization. Informally, it solves the following problem: Given an integer ${\displaystyle N}$, find its prime factors. It was invented in 1994 by the American mathematician Peter Shor.

On a quantum computer, to factor an integer ${\displaystyle N}$, Shor's algorithm runs in polynomial time (the time taken is polynomial in ${\displaystyle \log N}$, the size of the integer given as input). Specifically, it takes quantum gates of order ${\displaystyle O\!\left((\log N)^{2}(\log \log N)(\log \log \log N)\right)}$ using fast multiplication, thus demonstrating that the integer-factorization problem can be efficiently solved on a quantum computer and is consequently in the complexity class BQP. This is almost exponentially faster than the most efficient known classical factoring algorithm, the general number field sieve, which works in sub-exponential time — ${\displaystyle O\!\left(e^{1.9(\log N)^{1/3}(\log \log N)^{2/3}}\right)}$. The efficiency of Shor's algorithm is due to the efficiency of the quantum Fourier transform, and modular exponentiation by repeated squarings.

If a quantum computer with a sufficient number of qubits could operate without succumbing to quantum noise and other quantum-decoherence phenomena, then Shor's algorithm could be used to break public-key cryptography schemes, such as the widely used RSA scheme. RSA is based on the assumption that factoring large integers is computationally intractable. As far as is known, this assumption is valid for classical (non-quantum) computers; no classical algorithm is known that can factor integers in polynomial time. However, Shor's algorithm shows that factoring integers is efficient on an ideal quantum computer, so it may be feasible to defeat RSA by constructing a large quantum computer. It was also a powerful motivator for the design and construction of quantum computers, and for the study of new quantum-computer algorithms. It has also facilitated research on new cryptosystems that are secure from quantum computers, collectively called post-quantum cryptography.

In 2001, Shor's algorithm was demonstrated by a group at IBM, who factored ${\displaystyle 15}$ into ${\displaystyle 3\times 5}$, using an NMR implementation of a quantum computer with ${\displaystyle 7}$ qubits. After IBM's implementation, two independent groups implemented Shor's algorithm using photonic qubits, emphasizing that multi-qubit entanglement was observed when running the Shor's algorithm circuits. In 2012, the factorization of ${\displaystyle 15}$ was performed with solid-state qubits. Also, in 2012, the factorization of ${\displaystyle 21}$ was achieved, setting the record for the largest integer factored with Shor's algorithm.

🔗 Games

Nim is a mathematical game of strategy in which two players take turns removing (or "nimming") objects from distinct heaps or piles. On each turn, a player must remove at least one object, and may remove any number of objects provided they all come from the same heap or pile. Depending on the version being played, the goal of the game is either to avoid taking the last object, or to take the last object.

Variants of Nim have been played since ancient times. The game is said to have originated in China—it closely resembles the Chinese game of 捡石子 jiǎn-shízi, or "picking stones"—but the origin is uncertain; the earliest European references to Nim are from the beginning of the 16th century. Its current name was coined by Charles L. Bouton of Harvard University, who also developed the complete theory of the game in 1901, but the origins of the name were never fully explained.

Nim is typically played as a misère game, in which the player to take the last object loses. Nim can also be played as a normal play game, where the player taking the last object wins. This is called normal play because the last move is a winning move in most games, even though it is not the normal way that Nim is played. In either normal play or a misère game, when the number of heaps with at least two objects is exactly equal to one, the next player who takes next can easily win. If this removes either all or all but one objects from the heap that has two or more, then no heaps will have more than one object, so the players are forced to alternate removing exactly one object until the game ends. If the player leaves an even number of non-zero heaps (as the player would do in normal play), the player takes last; if the player leaves an odd number of heaps (as the player would do in misère play), then the other player takes last.

Normal play Nim (or more precisely the system of nimbers) is fundamental to the Sprague–Grundy theorem, which essentially says that in normal play every impartial game is equivalent to a Nim heap that yields the same outcome when played in parallel with other normal play impartial games (see disjunctive sum).

While all normal play impartial games can be assigned a Nim value, that is not the case under the misère convention. Only tame games can be played using the same strategy as misère Nim.

Nim is a special case of a poset game where the poset consists of disjoint chains (the heaps).

The evolution graph of the game of Nim with three heaps is the same as three branches of the evolution graph of the Ulam-Warburton automaton.

At the 1940 New York World's Fair Westinghouse displayed a machine, the Nimatron, that played Nim. From May 11, 1940 to October 27, 1940 only a few people were able to beat the machine in that six week period; if they did they were presented with a coin that said Nim Champ. It was also one of the first ever electronic computerized games. Ferranti built a Nim playing computer which was displayed at the Festival of Britain in 1951. In 1952 Herbert Koppel, Eugene Grant and Howard Bailer, engineers from the W. L. Maxon Corporation, developed a machine weighing 23 kilograms (50 lb) which played Nim against a human opponent and regularly won. A Nim Playing Machine has been described made from TinkerToy.

The game of Nim was the subject of Martin Gardner's February 1958 Mathematical Games column in Scientific American. A version of Nim is played—and has symbolic importance—in the French New Wave film Last Year at Marienbad (1961).

🔗 United States 🔗 Politics 🔗 Women's History 🔗 United States/U.S. presidential elections 🔗 United States/District of Columbia 🔗 Current events 🔗 Joe Biden 🔗 Women in Red

The inauguration of Joe Biden as the 46th President of the United States took place on January 20, 2021, before noon (EST), marking the commencement of the four-year term of Joe Biden as president and Kamala Harris as vice president. The inaugural ceremony took place on the West Front of the United States Capitol in Washington, D.C. and was the 59th presidential inauguration. Biden took the presidential oath of office, before which Harris took the vice presidential oath of office.

The inauguration took place amidst extraordinary political, public health, economic, and national security crises, including outgoing President Donald Trump's attempts to overturn the 2020 United States presidential election, which incited a storming of the Capitol, Trump's unprecedented second impeachment, and a threat of widespread civil unrest, which stimulated a nationwide law enforcement response. Festivities were sharply curtailed by efforts to prevent the spread of COVID-19 and mitigate the potential for violence near the Capitol. The live audience was limited to members of the 117th United States Congress and, for each, one guest of their choosing, resembling a State of the Union address. Public health measures such as mandatory face coverings, testing, temperature checks, and social distancing were used to protect participants in the ceremony.

"America United" and "Our Determined Democracy: Forging a More Perfect Union"—a reference to the Preamble to the United States Constitution—served as the inaugural themes.

🔗 Software 🔗 Software/Computing

Venix is a discontinued version of the Unix operating system for low-end computers, developed by VenturCom, a "company that specialises in the skinniest implementations of Unix".