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π Illegal prime
An illegal prime is a prime number that represents information whose possession or distribution is forbidden in some legal jurisdictions. One of the first illegal primes was found in 2001. When interpreted in a particular way, it describes a computer program that bypasses the digital rights management scheme used on DVDs. Distribution of such a program in the United States is illegal under the Digital Millennium Copyright Act. An illegal prime is a kind of illegal number.
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- "Illegal Prime Numbers" | 2021-04-12 | 218 Upvotes 107 Comments
- "Illegal prime" | 2018-04-27 | 267 Upvotes 192 Comments
- "Illegal prime" | 2016-11-22 | 39 Upvotes 26 Comments
- "Illegal prime number" | 2014-07-30 | 59 Upvotes 30 Comments
- "Illegal Prime Numbers" | 2013-10-17 | 178 Upvotes 58 Comments
- "Illegal prime" | 2010-01-11 | 152 Upvotes 76 Comments
π James-Lange Theory
The JamesβLange theory is a hypothesis on the origin and nature of emotions and is one of the earliest theories of emotion within modern psychology. It was developed by philosopher John Dewey and named for two 19th-century scholars, William James and Carl Lange (see modern criticism for more on the theory's origin). The basic premise of the theory is that physiological arousal instigates the experience of emotion. Previously people considered emotions as reactions to some significant events or their features, i.e. events come first, and then there is an emotional response. James-Lange theory proposed that the state of the body can induce emotions or emotional dispositions. In other words, this theory suggests that when we feel teary, it generates a disposition for sad emotions; when our heartbeat is out of normality, it makes us feel anxiety. Instead of feeling an emotion and subsequent physiological (bodily) response, the theory proposes that the physiological change is primary, and emotion is then experienced when the brain reacts to the information received via the body's nervous system. It proposes that each specific category of emotion is attached to a unique and different pattern of physiological arousal and emotional behaviour in reaction due to an exciting stimulus.
The theory has been criticized and modified over the course of time, as one of several competing theories of emotion. Modern theorists have built on its ideas by proposing that the experience of emotion is modulated by both physiological feedback and other information, rather than consisting solely of bodily changes, as James suggested. Psychologist Tim Dalgleish states that most modern affective neuroscientists would support such a viewpoint. In 2002, a research paper on the autonomic nervous system stated that the theory has been "hard to disprove".
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- "James-Lange Theory" | 2023-12-01 | 38 Upvotes 12 Comments
π Late Bronze Age Collapse
The Late Bronze Age collapse was a dark age transition in a large area covering much of Southeast Europe, West Asia and North Africa (comprising the overlapping regions of the Near East, the Eastern Mediterranean and North Africa, with the Balkans, the Aegean, Anatolia, and the Caucasus), which took place from the Late Bronze Age to the emerging Early Iron Age. It was a transition which historians believe was violent, sudden, and culturally disruptive, and involved societal collapse for some civilizations during the 12th century BCE. The palace economy of Mycenaean Greece, the Aegean region and Anatolia that characterized the Late Bronze Age disintegrated, transforming into the small isolated village cultures of the Greek Dark Ages. The Hittite Empire of Anatolia and the Levant collapsed, while states such as the Middle Assyrian Empire in Mesopotamia and the New Kingdom of Egypt survived but were considerably weakened.
Competing and even mutually compatible theories for the ultimate cause of the Late Bronze Age collapse have been made since the 19th century. These include volcanic eruptions, droughts, invasions by the Sea Peoples or migrations of Dorians, economic disruptions due to the rising use of ironworking, and changes in military technology and methods of war that saw the decline of chariot warfare.
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- "Late Bronze Age Collapse" | 2021-07-02 | 13 Upvotes 1 Comments
π Computus β The calculation to determine the day of Easter
The computus (Latin for 'computation') is a calculation that determines the calendar date of Easter. Easter is traditionally celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (an approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the calendar. The calculations produce different results depending on whether the Julian calendar or the Gregorian calendar is used.
In late antiquity, it was feasible for the entire Christian church to receive the date of Easter each year through an annual announcement from the Pope. By the early third century, however, communications had deteriorated to the point that the church put great value in a system that would allow the clergy to independently and consistently determine the date for themselves. Additionally, the church wished to eliminate dependencies on the Hebrew calendar, by deriving Easter directly from the vernal equinox.
In The Reckoning of Time (725), Bede uses computus as a general term for any sort of calculation, although he refers to the Easter cycles of Theophilus as a "Paschal computus." By the end of the 8th century, computus came to refer specifically to the calculation of time.
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- "Computus β The calculation to determine the day of Easter" | 2019-04-21 | 10 Upvotes 1 Comments
π Form Constant
A form constant is one of several geometric patterns which are recurringly observed during hypnagogia, hallucinations and altered states of consciousness.
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- "Form Constant" | 2020-03-01 | 32 Upvotes 10 Comments
π Exception That Proves the Rule
"The exception that proves the rule" (sometimes "the exception proves the rule") is a saying whose meaning is contested. Henry Watson Fowler's Modern English Usage identifies five ways in which the phrase has been used, and each use makes some sort of reference to the role that a particular case or event takes in relation to a more general rule.
Two original meanings of the phrase are usually cited. The first, preferred by Fowler, is that the presence of an exception applying to a specific case establishes ("proves") that a general rule exists. A more explicit phrasing might be "the exception that proves the existence of the rule." Most contemporary uses of the phrase emerge from this origin, although often in a way which is closer to the idea that all rules have their exceptions. The alternative origin given is that the word "prove" is used in the archaic sense of "test". In this sense, the phrase does not mean that an exception demonstrates a rule to be true or to exist, but that it tests the rule, thereby proving its value. There is little evidence of the phrase being used in this second way.
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- "Exception That Proves the Rule" | 2019-05-05 | 10 Upvotes 2 Comments
π Antimacassar
An antimacassar is a small cloth placed over the backs or arms of chairs, or the head or cushions of a sofa, to prevent soiling of the permanent fabric underneath. The name also refers to the cloth flap 'collar' on a sailor's shirt or top, used to keep macassar oil off the uniform.
Macassar oil was an unguent for the hair commonly used by men in the early 19th century, and reputed to have been manufactured from ingredients purchased in the port of Makassar in the Dutch East Indies. The poet Byron called it "thine incomparable oil, Macassar". The fashion for oiled hair became so widespread in the Victorian and the Edwardian period that housewives began to cover the arms and backs of their chairs with washable cloths to prevent the fabric coverings from being soiled. Around 1850, these started to be known as antimacassars. They were also installed in theatres, from 1865.
They came to have elaborate patterns, often in matching sets for the various items of parlour furniture; they were either made at home using a variety of techniques such as crochet or tatting, or purchased. The original antimacassars were usually made of stiff white crochet-work, but in the third quarter of the 19th century they became simpler and softer, usually fabric embroidered with a simple pattern in wool or silk.
By the beginning of the 20th century, antimacassars had become so associated in people's minds with the Victorian period that the word briefly became a figurative term for it. For example, antimacassars are suggestive of old-fashioned, Victorian-era women in Rebecca West's novel The Return of the Soldier.
Antimacassars are also used on the seat headrests of commercial passenger transport vehicles, such as trains, buses and, especially, aircraft, to prevent the transmission of hair dressings and conditions between passengers, simplify maintenance, and extend the life of fabrics.
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- "Antimacassar" | 2024-01-02 | 39 Upvotes 4 Comments
π Black Hole Starship
A black hole starship is a theoretical idea for enabling interstellar travel by propelling a starship by using a black hole as the energy source. The concept was first discussed in science fiction, notably in the book Imperial Earth by Arthur C. Clarke, and in the work of Charles Sheffield, in which energy extracted from a Kerr-Newman black hole is described as powering the rocket engines in the story "Killing Vector" (1978).
In a more detailed analysis, a proposal to create an artificial black hole and using a parabolic reflector to reflect its Hawking radiation was discussed in 2009 by Louis Crane and Shawn Westmoreland. Their conclusion was that it was on the edge of possibility, but that quantum gravity effects that are presently unknown will either make it easier, or make it impossible. Similar concepts were also sketched out by Bolonkin.
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- "Black Hole Starship" | 2014-06-08 | 12 Upvotes 2 Comments
π The Sokal Hoax
The Sokal affair, also called the Sokal hoax, was a scholarly publishing sting perpetrated by Alan Sokal, a physics professor at New York University and University College London. In 1996, Sokal submitted an article to Social Text, an academic journal of postmodern cultural studies. The submission was an experiment to test the journal's intellectual rigor and, specifically, to investigate whether "a leading North American journal of cultural studiesβwhose editorial collective includes such luminaries as Fredric Jameson and Andrew Rossβ[would] publish an article liberally salted with nonsense if (a) it sounded good and (b) it flattered the editors' ideological preconceptions".
The article, "Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity", was published in the Social Text spring/summer 1996 "Science Wars" issue. It proposed that quantum gravity is a social and linguistic construct. At that time, the journal did not practice academic peer review and it did not submit the article for outside expert review by a physicist. Three weeks after its publication in May 1996, Sokal revealed in Lingua Franca that the article was a hoax.
The hoax sparked a debate about the scholarly merit of commentary on the physical sciences by those in the humanities; the influence of postmodern philosophy on social disciplines in general; academic ethics, including whether Sokal was wrong to deceive the editors and readers of Social Text; and whether Social Text had exercised appropriate intellectual rigor.
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- "The Sokal Hoax" | 2023-11-09 | 74 Upvotes 92 Comments
- "The Sokal Hoax" | 2018-02-14 | 19 Upvotes 4 Comments
- "Sokal Affair" | 2017-08-30 | 18 Upvotes 10 Comments
- "The Sokal Affair" | 2009-04-15 | 26 Upvotes 15 Comments
π Comb Sort - Just As Good As Quick Sort
Comb sort is a relatively simple sorting algorithm originally designed by WΕodzimierz Dobosiewicz and Artur Borowy in 1980, later rediscovered by Stephen Lacey and Richard Box in 1991. Comb sort improves on bubble sort.
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- "Comb Sort - Just As Good As Quick Sort" | 2010-04-20 | 31 Upvotes 9 Comments