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πŸ”— False Vacuum

πŸ”— Physics

In quantum field theory, a false vacuum is a hypothetical vacuum that is relatively stable, but not in the most stable state possible. In this condition it is called metastable. It may last for a very long time in this state, but could eventually decay to the more stable one, an event known as false vacuum decay. The most common suggestion of how such a decay might happen in our universe is called bubble nucleation – if a small region of the universe by chance reached a more stable vacuum, this "bubble" (also called "bounce") would spread.

A false vacuum exists at a local minimum of energy and is therefore not completely stable, in contrast to a true vacuum, which exists at a global minimum and is stable.

πŸ”— Solutrean Hypothesis

πŸ”— Archaeology πŸ”— Indigenous peoples of North America

The Solutrean hypothesis on the peopling of the Americas claims that the earliest human migration to the Americas took place from Europe, with Solutreans traveling along pack ice in the Atlantic Ocean. This hypothesis contrasts with the mainstream academic narrative that the Americas were first populated by people crossing the Bering Strait to Alaska by foot on what was land during the Last Glacial Period or by following the Pacific coastline from Asia to America by boat.

The Solutrean hypothesis posits that around 21,000 years ago a group of people from the SolutrΓ© region of France, who are historically characterized by their unique lithic technique, migrated to North America along pack ice in the Atlantic Ocean. Once they made it to North America, their lithic technique dispersed around the continent (c. 13,000 years ago) to provide the basis for the later popularization of Clovis lithic technology. The premise behind the Solutrean Hypothesis is that the similarities between Clovis and Solutrean lithic technologies are evidence that the Solutreans were the first people to migrate to the Americas, dating far before mainstream scientific theories of the peopling of the Americas.

Originally proposed in the 1970s, the theory has received some support in the 2010s, notably by Dennis Stanford of the Smithsonian Institution and Bruce Bradley of the University of Exeter. However, according to David Meltzer, "[f]ew if any archaeologistsβ€”or, for that matter, geneticists, linguists, or physical anthropologistsβ€”take seriously the idea of a Solutrean colonization of America." The evidence for the hypothesis is considered more consistent with other scenarios. In addition to an interval of thousands of years between the Clovis and Solutrean eras, the two technologies show only incidental similarities. There is no evidence for any Solutrean seafaring, far less for any technology that could take humans across the Atlantic in an ice age. Genetic evidence supports the theory of Asian, not European, origins for the peopling of the Americas.

πŸ”— Montessori Education

πŸ”— Psychology πŸ”— Education πŸ”— Homeschooling πŸ”— Alternative education

The Montessori method of education is a type of educational method that involves children's natural interests and activities rather than formal teaching methods. A Montessori classroom places an emphasis on hands-on learning and developing real-world skills. It emphasizes independence and it views children as naturally eager for knowledge and capable of initiating learning in a sufficiently supportive and well-prepared learning environment. It discourages some conventional measures of achievement, such as grades and tests.

The method was started in the early 20th century by Italian physician Maria Montessori, who developed her theories through scientific experimentation with her students; the method has since been used in many parts of the world, in public and private schools alike.

A range of practices exist under the name "Montessori", which is not trademarked. Popular elements include mixed-age classrooms, student freedom (including their choices of activity), long blocks of uninterrupted work time, specially trained teachers and prepared environment. Scientific studies regarding the Montessori method are mostly positive, with a 2017 review stating that "broad evidence" exists for its efficacy.

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πŸ”— Circulation of Elites

πŸ”— Sociology

The circulation of elites is a theory of regime change described by Italian sociologist Vilfredo Pareto (1848–1923).

Changes of regime, revolutions, and so on occur not when rulers are overthrown from below, but when one elite replaces another. The role of ordinary people in such transformation is not that of initiators or principal actors, but as followers and supporters of one elite or another.

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πŸ”— Miyake event – estimated to be every 400–2400 years

πŸ”— Astronomy πŸ”— Geology πŸ”— Weather πŸ”— Astronomy/Solar System πŸ”— Weather/Weather πŸ”— Weather/Space weather

A Miyake event is an observed sharp enhancement of the production of cosmogenic isotopes by cosmic rays. It can be marked by a spike in the concentration of radioactive carbon isotope 14
C
in tree rings, as well as 10
Be
and 36
Cl
in ice cores, which are all independently dated. At present, five significant events are known (7176 BCE, 5259 BCE, 660 BCE, 774 CE, 993 CE) for which the spike in 14
C
is quite remarkable, i.e. above 1% rise over a period of 2 years, and four more events (12,350Β BCE, 5410 BCE, 1052 CE, 1279 CE) need independent confirmation. It is not known how often Miyake events occur, but from the available data it is estimated to be every 400–2400 years.

There is strong evidence that Miyake events are caused by extreme solar particle events and they are likely related to super-flares discovered on solar-like stars. Although Miyake events are based on extreme year-to-year rises of 14
C
concentration, the duration of the periods over which the 14
C
levels increase or stay at high levels is longer than one year. However, a universal cause and origin of all the events is not yet established in science, and some of the events may be caused by other phenomena coming from outer space (such as a gamma-ray burst).

A recently reported sharp spike in 14
C
that occurred between 12,350 and 12,349Β BCE, may represent the largest known Miyake event. This event was identified during a study conducted by an international team of researchers who measured radiocarbon levels in ancient trees recovered from the eroded banks of the Drouzet River, near Gap, France, in the Southern French Alps. According to the initial study the new event is roughly twice the size of the Ξ”14
C
increase for more recent 774Β CE and 993Β CE events, but the strength of the corresponding solar storm is not yet assessed. However, the newly discovered 12,350 BCE event has not yet been independently confirmed in wood from other regions, nor it is reliably supported by a clear corresponding spike in other isotopes (such as Beryllium-10) that are usually used in combination for absolute radiometric dating.

A Miyake event occurring in modern conditions might have significant impacts on global technological infrastructure such as satellites, telecommunications, and power grids.

πŸ”— Kaffeklubben Island – northernmost undisputed point of land on Earth

πŸ”— Geography πŸ”— Arctic πŸ”— Islands πŸ”— Greenland

Kaffeklubben Island or Coffee Club Island (Danish: Kaffeklubben Ø; Greenlandic: Inuit Qeqertaat) is an uninhabited island lying off the northern shore of Greenland. It contains the northernmost undisputed point of land on Earth.

πŸ”— RAL Color Standard

πŸ”— Color

RAL is a colour management system used in Europe that is created and administered by the German RAL gGmbH (RAL non-profit LLC), which is a subsidiary of the German RAL Institute. In colloquial speech, RAL refers to the RAL Classic system, mainly used for varnish and powder coating, but now plastics as well. Approved RAL products are provided with a hologram to make unauthorised versions difficult to produce. Imitations may show different hue and colour when observed under various light sources.

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πŸ”— Modern Arabic Mathematical Notation

πŸ”— Mathematics

Modern Arabic mathematical notation is a mathematical notation based on the Arabic script, used especially at pre-university levels of education. Its form is mostly derived from Western notation, but has some notable features that set it apart from its Western counterpart. The most remarkable of those features is the fact that it is written from right to left following the normal direction of the Arabic script. Other differences include the replacement of the Greek and Latin alphabet letters for symbols with Arabic letters and the use of Arabic names for functions and relations.

πŸ”— Mummy Brown

πŸ”— Ancient Egypt πŸ”— Color πŸ”— Archaeology πŸ”— Visual arts

Mummy brown, also known as Egyptian brown or Caput Mortuum,:β€Š254β€Š is a rich brown bituminous pigment with good transparency, sitting between burnt umber and raw umber in tint. The pigment was made from the flesh of mummies mixed with white pitch and myrrh. Mummy brown was extremely popular from the mid-eighteenth to the nineteenth centuries. However, fresh supplies of mummies diminished, and artists were less satisfied with the pigment's permanency and finish. By 1915, demand had significantly declined. Suppliers ceased to offer it by the middle of the twentieth century.:β€Š82β€Š

Mummy brown was one of the favourite colours of the Pre-Raphaelites. It was used by many artists, including Eugene Delacroix, William Beechey, Edward Burne-Jones, Lawrence Alma-Tadema, and Martin Drolling.

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