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π Rule of 72
In finance, the rule of 72, the rule of 70 and the rule of 69.3 are methods for estimating an investment's doubling time. The rule number (e.g., 72) is divided by the interest percentage per period (usually years) to obtain the approximate number of periods required for doubling. Although scientific calculators and spreadsheet programs have functions to find the accurate doubling time, the rules are useful for mental calculations and when only a basic calculator is available.
These rules apply to exponential growth and are therefore used for compound interest as opposed to simple interest calculations. They can also be used for decay to obtain a halving time. The choice of number is mostly a matter of preference: 69 is more accurate for continuous compounding, while 72 works well in common interest situations and is more easily divisible. There is a number of variations to the rules that improve accuracy. For periodic compounding, the exact doubling time for an interest rate of r percent per period is
- ,
where t is the number of periods required. The formula above can be used for more than calculating the doubling time. If one wants to know the tripling time, for example, replace the constant 2 in the numerator with 3. As another example, if one wants to know the number of periods it takes for the initial value to rise by 50%, replace the constant 2 with 1.5.
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- "Rule of 72" | 2011-03-20 | 47 Upvotes 13 Comments
π Nazi Book Burnings
The Nazi book burnings were a campaign conducted by the German Student Union (the "DSt") to ceremonially burn books in Nazi Germany and Austria in the 1930s. The books targeted for burning were those viewed as being subversive or as representing ideologies opposed to Nazism. These included books written by Jewish, pacifist, religious, liberal, anarchist, socialist, communist, and sexologist authors among others. The first books burned were those of Karl Marx and Karl Kautsky.
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- "Nazi Book Burnings" | 2018-12-24 | 11 Upvotes 1 Comments
π Holon
A holon (Greek: ὠλον, from ὠλοΟ, holos, 'whole' and -ΞΏΞ½, -on, 'part') is something that is simultaneously a whole in and of itself, as well as a part of a larger whole. In other words, holons can be understood as the constituent partβwholes of a hierarchy.
The holon represents a way to overcome the dichotomy between parts and wholes, as well as a way to account for both the self-assertive and the integrative tendencies of organisms. The term was coined by Arthur Koestler in The Ghost in the Machine (1967). In Koestler's formulations, a holon is something that has integrity and identity while simultaneously being a part of a larger system; it is a subsystem of a greater system.
Holons are sometimes discussed in the context of self-organizing holarchic open (SOHO) systems.
π Foldering
Foldering is the practice of communicating via messages saved to the "drafts" folder of an email or other electronic messaging account that is accessible by multiple people. The messages are never actually sent.
Foldering has been described as a digital equivalent of a dead drop.
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- "Foldering" | 2023-08-17 | 35 Upvotes 4 Comments
π The squircle is a shape intermediate between a square and a circle
A squircle is a shape intermediate between a square and a circle. There are at least two definitions of "squircle" in use, the most common of which is based on the superellipse. The word "squircle" is a portmanteau of the words "square" and "circle". Squircles have been applied in design and optics.
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- "The squircle is a shape intermediate between a square and a circle" | 2022-04-22 | 13 Upvotes 2 Comments
π CorsiβRosenthal Box
The CorsiβRosenthal Box, also called a CorsiβRosenthal Cube or a Comparetto Cube, is a design for a do-it-yourself air purifier that can be built comparatively inexpensively. It was designed during the COVID-19 pandemic with the goal of reducing the levels of airborne viral particles in indoor settings.
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- "CorsiβRosenthal Box" | 2022-05-19 | 81 Upvotes 21 Comments
π Catullus 16
PΔdΔ«cΔbΕ ego vΕs et irrumΔbΕ ("I will sodomize and face-fuck you") is the first line, sometimes used as a title, of Carmen 16 in the collected poems of Gaius Valerius Catullus (c. 84 BC β c. 54 BC). The poem, written in a hendecasyllabic (11-syllable) meter, was considered so explicit that a full English translation was not published until the late twentieth century. The first line has been called "one of the filthiest expressions ever written in Latinβor in any other language, for that matter."
Carmen 16 is significant in literary history as an artistic work censored for its obscenity, but also because the poem raises questions about the proper relation of the poet, or his life, to the work. Later Latin poets referenced the poem not for its invective, but as a justification for subject matter that challenged the prevailing decorum or moral orthodoxy. Ovid, Pliny the Younger, Martial, and Apuleius all invoked the authority of Catullus in asserting that while the poet should be a respectable person, his work should not be constrained or restricted.
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- "Catullus 16" | 2018-10-25 | 22 Upvotes 5 Comments
π Iannis Xenakis - Wikipedia, the free encyclopedia
Iannis Xenakis (also spelt as Yannis Xenakis) (Greek: ΞΞΉΞ¬Ξ½Ξ½Ξ·Ο (ΞάννηΟ) ΞΞ΅Ξ½Ξ¬ΞΊΞ·Ο [ΛΚanis kseΛnacis]; 29 May 1922 β 4 February 2001) was a Greek-French composer, music theorist, architect, performance director and engineer. After 1947, he fled Greece, becoming a naturalized citizen of France. He is considered an important post-World War II composer whose works helped revolutionize 20th-century classical music.
Xenakis pioneered the use of mathematical models in music such as applications of set theory, stochastic processes and game theory and was also an important influence on the development of electronic and computer music. He integrated music with architecture, designing music for pre-existing spaces, and designing spaces to be integrated with specific music compositions and performances.
Among his most important works are Metastaseis (1953β54) for orchestra, which introduced independent parts for every musician of the orchestra; percussion works such as Psappha (1975) and Pléïades (1979); compositions that introduced spatialization by dispersing musicians among the audience, such as Terretektorh (1966); electronic works created using Xenakis's UPIC system; and the massive multimedia performances Xenakis called polytopes, that were a summa of his interests and skills. Among the numerous theoretical writings he authored, the book Formalized Music: Thought and Mathematics in Composition (French edition 1963, English translation 1971) is regarded as one of his most important. As an architect, Xenakis is primarily known for his early work under Le Corbusier: the Sainte Marie de La Tourette, on which the two architects collaborated, and the Philips Pavilion at Expo 58, which Xenakis designed by himself.
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- "Iannis Xenakis - Wikipedia, the free encyclopedia" | 2010-05-20 | 18 Upvotes 5 Comments
π Mariko Aoki Phenomenon
The Mariko Aoki phenomenon (ιζ¨γΎγγηΎθ±‘, Aoki Mariko genshΕ) is a Japanese expression referring to an urge to defecate that is suddenly felt after entering bookstores. The phenomenon's name derives from the name of the woman who mentioned the phenomenon in a magazine article in 1985. According to Japanese social psychologist Shozo Shibuya, the specific causes that trigger a defecation urge in bookstores are not yet clearly understood (as of 2014). There are also some who are skeptical about whether such a peculiar phenomenon really exists at all, and it is sometimes discussed as one type of urban myth.
The series of processes through which being in a bookstore leads to an awareness of a defecation urge is something that cannot be explained from a medical perspective as a single pathological concept, at least at present. According to a number of discussions on the topic, even if it can be sufficiently found that this phenomenon actually exists, it is a concept that would be difficult to be deemed a specific pathological entity (such as a "Mariko Aoki disease", for example). On the other hand, it is also a fact that a considerable number of the intellectuals (particularly clinicians) who discuss this phenomenon have adopted existing medical terminology such as from diagnostics and pathology. Borrowing from this approach, this article also uses expressions from existing medical terminology for convenience.
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- "The Mariko Aoki Phenomenon" | 2024-05-11 | 15 Upvotes 2 Comments
- "Mariko Aoki phenomenon" | 2018-12-30 | 11 Upvotes 2 Comments
π Deseret Alphabet
The Deseret alphabet ( (listen); Deseret: ππ―π π¨ππ―π» or ππ―ππ²ππ―π») is a phonemic English-language spelling reform developed between 1847 and 1854 by the board of regents of the University of Deseret under the leadership of Brigham Young, the second president of the Church of Jesus Christ of Latter-day Saints (LDS Church). George D. Watt is reported to have been the most actively involved in the development of the script,:β159β as well as being its first serious user.:β12β
The Deseret alphabet was an outgrowth of the idealism and utopianism of Young and the early LDS Church. Young and the Mormon pioneers believed "all aspects of life" were in need of reform for the imminent millenniumand the Deseret alphabet was just one of many ways they sought to bring about a complete "transformation in society",:β142β in anticipation of the Second Coming of Jesus. Young wrote of the reform that "it would represent every sound used in the construction of any known language; and, in fact, a step and partial return to a pure language which has been promised unto us in the latter days," the Adamic language spoken before the Tower of Babel.
In public statements, Young claimed the alphabet would replace the traditional Latin alphabet with an alternative, more phonetically accurate alphabet for the English language. This would offer immigrants an opportunity to learn to read and write English, he said, the orthography of which is often less phonetically consistent than those of many other languages.:β65β66β Similar neographies have been attempted, the most well-known of which for English is the Shavian alphabet.
Young also prescribed the learning of Deseret to the school system, stating "It will be the means of introducing uniformity in our orthography, and the years that are now required to learn to read and spell can be devoted to other studies."
During the alphabet's heyday between 1854 and 1869, scriptural passages in newspapers, selected church records, a $5 gold coin, and occasional street signs and correspondence used the new letters. In 1868-9, after much difficulty creating suitable fonts, four books were printed: two school primers, the full Book of Mormon, and a portion of it titled the Book of Nephi.
Despite heavy and costly promotion by the early LDS Church, the alphabet never enjoyed prolonged widespread use and has been regarded by historians as a failure. However, in recent years, aided by digital typography, the Deseret Alphabet has been revived as a cultural heirloom.
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- "Deseret Alphabet" | 2023-05-01 | 140 Upvotes 71 Comments