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🔗 Mathematics

In mathematics before the 1970s, the term umbral calculus referred to the surprising similarity between seemingly unrelated polynomial equations and certain "shadowy" techniques used to "prove" them. These techniques were introduced by John Blissard (1861) and are sometimes called Blissard's symbolic method. They are often attributed to Édouard Lucas (or James Joseph Sylvester), who used the technique extensively.

🔗 California 🔗 Companies 🔗 California/San Francisco Bay Area 🔗 Internet 🔗 Food and drink

Webvan was a dot-com company and grocery business that filed for bankruptcy in 2001 after 3 years of operation. It was headquartered in Foster City, California, United States. It delivered products to customers' homes within a 30-minute window of their choosing. At its peak, it offered service in ten US markets: the San Francisco Bay Area; Dallas; Sacramento; San Diego; Los Angeles; Orange County, California; Chicago; Seattle; Portland, Oregon; and Atlanta, Georgia. The company had hoped to expand to 26 cities by 2001.

🔗 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.

🔗 Biography/arts and entertainment 🔗 Animation

Robert Herman "Bob" Givens (March 2, 1918 – December 14, 2017) was an American animator, character designer, and layout artist. He worked for numerous animation studios during his career, including Walt Disney Animation Studios, Warner Bros. Cartoons, Hanna-Barbera, and DePatie–Freleng Enterprises, beginning his career during the late 1930s and continuing until the early 2000s. He was a frequent collaborator with director Chuck Jones, working with Jones both at Warner Bros. and Jones' own production company.

🔗 Game theory

Sprouts is a paper-and-pencil game that can be enjoyed simply by both adults and children. Yet it also can be analyzed for its significant mathematical properties. It was invented by mathematicians John Horton Conway and Michael S. Paterson at Cambridge University in the early 1960s. Setup is even simpler than the popular Dots and Boxes game, but game-play develops much more artistically and organically.

🔗 Psychology 🔗 Sociology 🔗 Media

Parasocial interaction (PSI) refers to a kind of psychological relationship experienced by an audience in their mediated encounters with performers in the mass media, particularly on television and on online platforms. Viewers or listeners come to consider media personalities as friends, despite having no or limited interactions with them. PSI is described as an illusionary experience, such that media audiences interact with personas (e.g., talk show hosts, celebrities, fictional characters, social media influencers) as if they are engaged in a reciprocal relationship with them. The term was coined by Donald Horton and Richard Wohl in 1956.

A parasocial interaction, an exposure that garners interest in a persona, becomes a parasocial relationship after repeated exposure to the media persona causes the media user to develop illusions of intimacy, friendship, and identification. Positive information learned about the media persona results in increased attraction, and the relationship progresses. Parasocial relationships are enhanced due to trust and self-disclosure provided by the media persona. Media users are loyal and feel directly connected to the persona, much as they are connected to their close friends, by observing and interpreting their appearance, gestures, voice, conversation, and conduct. Media personas have a significant amount of influence over media users, positive or negative, informing the way that they perceive certain topics or even their purchasing habits. Studies involving longitudinal effects of parasocial interactions on children are still relatively new, according to developmental psychologist Sandra L. Calvert.

Social media introduces additional opportunities for parasocial relationships to intensify because it provides more opportunities for intimate, reciprocal, and frequent interactions between the user and persona. These virtual interactions may involve commenting, following, liking, or direct messaging. The consistency in which the persona appears could also lead to a more intimate perception in the eyes of the user.

🔗 United States 🔗 Biography 🔗 California 🔗 Aviation 🔗 Spaceflight 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Biography/science and academia 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 LGBT studies 🔗 Aviation/aerospace biography 🔗 Chemistry 🔗 Military history/World War II 🔗 Military history/Cold War 🔗 Libertarianism 🔗 California/Southern California 🔗 California/Los Angeles area 🔗 Thelema 🔗 Occult

John Whiteside Parsons (born Marvel Whiteside Parsons; October 2, 1914 – June 17, 1952) was an American rocket engineer, chemist, and Thelemite occultist. Associated with the California Institute of Technology (Caltech), Parsons was one of the principal founders of both the Jet Propulsion Laboratory (JPL) and the Aerojet Engineering Corporation. He invented the first rocket engine to use a castable, composite rocket propellant, and pioneered the advancement of both liquid-fuel and solid-fuel rockets.

Born in Los Angeles, Parsons was raised by a wealthy family on Orange Grove Boulevard in Pasadena. Inspired by science fiction literature, he developed an interest in rocketry in his childhood and in 1928 began amateur rocket experiments with school friend Edward S. Forman. He dropped out of Pasadena Junior College and Stanford University due to financial difficulties during the Great Depression, and in 1934 he united with Forman and graduate Frank Malina to form the Caltech-affiliated Guggenheim Aeronautical Laboratory (GALCIT) Rocket Research Group, supported by GALCIT chairman Theodore von Kármán. In 1939 the GALCIT Group gained funding from the National Academy of Sciences (NAS) to work on Jet-Assisted Take Off (JATO) for the U.S. military. After the U.S. entered World War II, they founded Aerojet in 1942 to develop and sell JATO technology; the GALCIT Group became JPL in 1943.

Following some brief involvement with Marxism in 1939, Parsons converted to Thelema, the new religious movement founded by the English occultist Aleister Crowley. Together with his first wife, Helen Northrup, Parsons joined the Agape Lodge, the Californian branch of the Thelemite Ordo Templi Orientis (O.T.O.) in 1941. At Crowley's bidding, Parsons replaced Wilfred Talbot Smith as its leader in 1942 and ran the Lodge from his mansion on Orange Grove Boulevard. Parsons was expelled from JPL and Aerojet in 1944 owing to the Lodge's infamous reputation and to his hazardous workplace conduct.

In 1945, Parsons separated from Helen, after having an affair with her sister Sara; when Sara left him for L. Ron Hubbard, Parsons conducted the Babalon Working, a series of rituals intended to invoke the Thelemic goddess Babalon on Earth. He and Hubbard continued the working with Marjorie Cameron, whom Parsons married in 1946. After Hubbard and Sara defrauded him of his life savings, Parsons resigned from the O.T.O., then held various jobs while acting as a consultant for Israel's rocket program. Amid McCarthyism, Parsons was accused of espionage and left unable to work in rocketry. In 1952 Parsons died at the age of 37 in a home laboratory explosion that attracted national media attention; the police ruled it an accident, but many associates suspected suicide or murder.

Parsons's libertarian and occult writings were published posthumously. Historians of Western esoteric tradition cite him as one of the more prominent figures in propagating Thelema across North America. Although academic interest in his scientific career was negligible, historians have come to recognize Parsons's contributions to rocket engineering. For these innovations, his advocacy of space exploration and human spaceflight, and his role in founding JPL and Aerojet, Parsons is regarded as among the most important figures in the history of the U.S. space program. He has been the subject of several biographies and fictionalized portrayals.

🔗 California 🔗 Skepticism 🔗 Geography 🔗 Alternative Views 🔗 Geology

Sailing stones (also known as sliding rocks, walking rocks, rolling stones, and moving rocks), are a geological phenomenon where rocks move and inscribe long tracks along a smooth valley floor without human or animal intervention. The movement of the rocks occurs when large ice sheets a few millimeters thick and floating in an ephemeral winter pond start to break up during sunny days. Frozen during cold winter nights, these thin floating ice panels are driven by wind and shove rocks at speeds up to 5 meters per minute.

Trails of sliding rocks have been observed and studied in various locations, including Little Bonnie Claire Playa in Nevada, and most famously at Racetrack Playa, Death Valley National Park, California, where the number and length of tracks are notable.

🔗 Linguistics 🔗 Linguistics/Etymology

OK (spelling variations include okay, O.K., and ok) is an English word (originally American English) denoting approval, acceptance, agreement, assent, acknowledgment, or a sign of indifference. OK is frequently used as a loanword in other languages. It has been described as the most frequently spoken or written word on the planet. The origins of the word are disputed.

As an adjective, OK principally means "adequate" or "acceptable" as a contrast to "bad" ("The boss approved this, so it is OK to send out"); it can also mean "mediocre" when used in contrast with "good" ("The french fries were great, but the burger was just OK"). It fulfills a similar role as an adverb ("Wow, you did OK for your first time skiing!"). As an interjection, it can denote compliance ("OK, I will do that"), or agreement ("OK, that is fine"). It can mean "assent" when it is used as a noun ("the boss gave her the OK to the purchase") or, more colloquially, as a verb ("the boss OKed the purchase"). OK, as an adjective, can express acknowledgement without approval. As a versatile discourse marker or back-channeling item, it can also be used with appropriate intonation to show doubt or to seek confirmation ("OK?", "Is that OK?").

🔗 Video games 🔗 Molecular Biology 🔗 Video games/Sega 🔗 Molecular Biology/Molecular and Cell Biology 🔗 Molecular Biology/Genetics 🔗 Molecular Biology/Cell Signaling

Sonic hedgehog protein (SHH) is encoded for by the SHH gene. The protein is named after the character Sonic the Hedgehog.

This signaling molecule is key in regulating embryonic morphogenesis in all animals. SHH controls organogenesis and the organization of the central nervous system, limbs, digits and many other parts of the body. Sonic hedgehog is a morphogen that patterns the developing embryo using a concentration gradient characterized by the French flag model. This model has a non-uniform distribution of SHH molecules which governs different cell fates according to concentration. Mutations in this gene can cause holoprosencephaly, a failure of splitting in the cerebral hemispheres, as demonstrated in an experiment using SHH knock-out mice in which the forebrain midline failed to develop and instead only a single fused telencephalic vesicle resulted.

Sonic hedgehog still plays a role in differentiation, proliferation, and maintenance of adult tissues. Abnormal activation of SHH signaling in adult tissues has been implicated in various types of cancers including breast, skin, brain, liver, gallbladder and many more.