To stay up to date you can also follow on Mastodon.

🔗 Computer science

Bead sort, also called gravity sort, is a natural sorting algorithm, developed by Joshua J. Arulanandham, Cristian S. Calude and Michael J. Dinneen in 2002, and published in The Bulletin of the European Association for Theoretical Computer Science. Both digital and analog hardware implementations of bead sort can achieve a sorting time of O(n); however, the implementation of this algorithm tends to be significantly slower in software and can only be used to sort lists of positive integers. Also, it would seem that even in the best case, the algorithm requires O(n²) space.

🔗 Mathematics

The hairy ball theorem of algebraic topology (sometimes called the hedgehog theorem in Europe) states that there is no nonvanishing continuous tangent vector field on even-dimensional n-spheres. For the ordinary sphere, or 2‑sphere, if f is a continuous function that assigns a vector in R³ to every point p on a sphere such that f(p) is always tangent to the sphere at p, then there is at least one p such that f(p) = 0. The theorem was first stated by Henri Poincaré in the late 19th century, and first proven in 1912 by Luitzen Egbertus Jan Brouwer.

The theorem has been expressed colloquially as "you can't comb a hairy ball flat without creating a cowlick" or "you can't comb the hair on a coconut".

🔗 Computing 🔗 Perl

Raku rules are the regular expression, string matching and general-purpose parsing facility of Raku, and are a core part of the language. Since Perl's pattern-matching constructs have exceeded the capabilities of formal regular expressions for some time, Raku documentation refers to them exclusively as regexes, distancing the term from the formal definition.

Raku provides a superset of Perl 5 features with respect to regexes, folding them into a larger framework called rules, which provide the capabilities of a parsing expression grammar, as well as acting as a closure with respect to their lexical scope. Rules are introduced with the rule keyword, which has a usage quite similar to subroutine definitions. Anonymous rules can be introduced with the regex (or rx) keyword, or simply be used inline as regexes were in Perl 5 via the m (matching) or s (substitution) operators.

🔗 Military history 🔗 Fashion

A necktie, or simply a tie, is a long piece of cloth, worn, usually by men, for decorative purposes around the neck, resting under the shirt collar and knotted at the throat.

Variants include the ascot, bow, bolo, zipper, cravat, and knit. The modern necktie, ascot, and bow tie are descended from the cravat. Neckties are generally unsized, but may be available in a longer size. In some cultures men and boys wear neckties as part of regular office attire or formal wear. Some women wear them as well but usually not as often as men. Neckties can also be worn as part of a uniform (e.g. military, school, waitstaff), whereas some choose to wear them as everyday clothing attire. Neckties are traditionally worn with the top shirt button fastened, and the tie knot resting between the collar points.

🔗 Mathematics

The probabilistic method is a nonconstructive method, primarily used in combinatorics and pioneered by Paul Erdős, for proving the existence of a prescribed kind of mathematical object. It works by showing that if one randomly chooses objects from a specified class, the probability that the result is of the prescribed kind is strictly greater than zero. Although the proof uses probability, the final conclusion is determined for certain, without any possible error.

This method has now been applied to other areas of mathematics such as number theory, linear algebra, and real analysis, as well as in computer science (e.g. randomized rounding), and information theory.

🔗 Psychology 🔗 Sociology

Déformation professionnelle (French: [defɔʁmasjɔ̃ pʁɔfɛsjɔnɛl], professional deformation or job conditioning) is a tendency to look at things from the point of view of one's own profession or special expertise, rather than from a broader or humane perspective. It is often translated as "professional deformation", though French déformation can also be translated as "distortion". The implication is that professional training, and its related socialization, often result in a distortion of the way one views the world. Nobel laureate Alexis Carrel observed, "Every specialist, owing to a well-known professional bias, believes that he understands the entire human being, while in reality he only grasps a tiny part of him."

As a term in psychology, it was likely coined by the Belgian sociologist Daniel Warnotte or Russian-American sociologist Pitirim Sorokin.

🔗 Transport

Smeed's Law, named after R. J. Smeed, who first proposed the relationship in 1949, is a purported empirical rule relating traffic fatalities to traffic congestion as measured by the proxy of motor vehicle registrations and country population. The law proposes that increasing traffic volume (an increase in motor vehicle registrations) leads to an increase in fatalities per capita, but a decrease in fatalities per vehicle.

Smeed also predicted that the average speed of traffic in central London would always be nine miles per hour, because that is the minimum speed that people tolerate. He predicted that any intervention intended to speed traffic would only lead to more people driving at this "tolerable" speed unless there were any other disincentives against doing so.

His hypothesis in relation to road traffic safety has been refuted by several authors, who point out that fatalities per person have decreased in many countries, when the "Law" requires that they should increase as long as the number of vehicles per person continues to rise.

🔗 United States 🔗 International relations 🔗 Disaster management 🔗 Medicine 🔗 Viruses 🔗 Canada 🔗 Death 🔗 Agriculture 🔗 Mexico

The 2009 flu pandemic or swine flu was an influenza pandemic that lasted from January 2009 to August 2010, and the second of the two pandemics involving H1N1 influenza virus (the first being the 1918–1920 Spanish flu pandemic), albeit a new strain. First described in April 2009, the virus appeared to be a new strain of H1N1, which resulted from a previous triple reassortment of bird, swine, and human flu viruses further combined with a Eurasian pig flu virus, leading to the term "swine flu". According to WHO, the laboratory confirmed death toll is more than 18,036. Meanwhile, some studies estimated that 11 to 21 percent of the global population at the time – or around 700 million to 1.4 billion people (out of a total of 6.8 billion) – contracted the illness. This was more than the number of people infected by the Spanish flu pandemic, but only resulted in about 150,000 to 575,000 fatalities for the 2009 pandemic. A follow-up study done in September 2010 showed that the risk of serious illness resulting from the 2009 H1N1 flu was no higher than that of the yearly seasonal flu. For comparison, the WHO estimates that 250,000 to 500,000 people die of seasonal flu annually.

Unlike most strains of influenza, the Pandemic H1N1/09 virus does not disproportionately infect adults older than 60 years; this was an unusual and characteristic feature of the H1N1 pandemic. Even in the case of previously very healthy people, a small percentage develop pneumonia or acute respiratory distress syndrome (ARDS). This manifests itself as increased breathing difficulty and typically occurs three to six days after initial onset of flu symptoms. The pneumonia caused by flu can be either direct viral pneumonia or a secondary bacterial pneumonia. A November 2009 New England Journal of Medicine article recommended that flu patients whose chest X-ray indicates pneumonia receive both antivirals and antibiotics. In particular, it is a warning sign if a child (and presumably an adult) seems to be getting better and then relapses with high fever, as this relapse may be bacterial pneumonia.