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π Carolyn Shoemaker has died
Carolyn Jean Spellmann Shoemaker (June 24, 1929 β August 13, 2021) was an American astronomer and a co-discoverer of Comet ShoemakerβLevyΒ 9. She once held the record for most comets discovered by an individual.
Although Shoemaker earned degrees in history, political science and English literature, she had little interest in science until she met and married geologist Eugene M. ("Gene") Shoemaker in 1950β51. She later said that his explanations of his work thrilled her. Despite her relative inexperience and lack of a science degree, California Institute of Technology (Caltech) had no objection to her joining Gene's team there as a research assistant. She had already shown herself to be unusually patient, and demonstrated exceptional stereoscopic vision, which were particularly valuable qualities for looking for objects in near-Earth space.
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- "Carolyn Shoemaker has died" | 2021-08-16 | 115 Upvotes 7 Comments
π List of Countries by Vehicles per Capita
This article is a list of countries by the number of road motor vehicles per 1,000 inhabitants. This includes cars, vans, buses, and freight and other trucks; but excludes motorcycles and other two-wheelers.
China has the largest fleet of motor vehicles in the world in 2021, with 292 million cars, and in 2009 became the world's largest new car market as well. In 2011, a total of 80 million cars and commercial vehicles were built, led by China, with 18.4 million motor vehicles manufactured.
π The Overview Effect
The overview effect is a cognitive shift in awareness reported by some astronauts during spaceflight, often while viewing the Earth from outer space.
It is the experience of seeing firsthand the reality of the Earth in space, which is immediately understood to be a tiny, fragile ball of life, "hanging in the void", shielded and nourished by a paper-thin atmosphere. From space, national boundaries vanish, the conflicts that divide people become less important, and the need to create a planetary society with the united will to protect this "pale blue dot" becomes both obvious and imperative.
The thing that really surprised me was that it [Earth] projected an air of fragility. And why, I donβt know. I donβt know to this day. I had a feeling itβs tiny, itβs shiny, itβs beautiful, itβs home, and itβs fragile.
Astronauts Michael Collins, Ron Garan, Rusty Schweikart, Edgar Mitchell, Tom Jones, Scott Kelly, James Irwin, Mike Massimino, AndrΓ© Kuipers, Chris Hadfield, and Sally Ride are all reported to have experienced the effect.
The term and concept were coined in 1987 by Frank White, who explored the theme in his book The Overview EffectΒ β Space Exploration and Human Evolution (Houghton-Mifflin, 1987), (AIAA, 1998).
In 2018, the SpaceBuzz project was created so "children around the world can also get to experience the Overview Effect." It was announced in a press release on December 20 by astronaut AndrΓ© Kuipers on the European Space Agency's (ESA) website. Spacebuzz aims to give children an overview effect like experience using virtual reality (VR) in order to have the same insight astronauts have when seeing planet Earth from space. Spacebuzz is a project started by the Overview Effect Foundation backed by ESA and the Netherlands Space Office..
In late 2019 it was reported that researchers at the University of Missouri aimed to reproduce the experience, with an isolation tank, half a tonne of Epsom salts, and a waterproof VR headset.
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- "The Overview Effect" | 2021-08-15 | 44 Upvotes 27 Comments
- "The Overview Effect" | 2019-08-21 | 47 Upvotes 6 Comments
π A Tesla Valve
A Tesla valve, called by Tesla a valvular conduit, is a fixed-geometry passive check valve. It allows a fluid to flow preferentially in one direction, without moving parts. The device is named after Nikola Tesla, who was awarded U.S. Patent 1,329,559 in 1920 for its invention. The patent application describes the invention as follows:
The interior of the conduit is provided with enlargements, recesses, projections, baffles, or buckets which, while offering virtually no resistance to the passage of the fluid in one direction, other than surface friction, constitute an almost impassable barrier to its flow in the opposite direction.
Tesla illustrates this with the drawing, showing one possible construction with a series of eleven flow-control segments, although any other number of such segments could be used as desired to increase or decrease the flow regulation effect.
One computational fluid dynamics simulation of Tesla valves with two and four segments showed that the flow resistance in the blocking (or reverse) direction was about 15 and 40 times greater, respectively, than the unimpeded (or forward) direction. This lends support to Tesla's patent assertion that in the valvular conduit in his diagram, a pressure ratio "approximating 200 can be obtained so that the device acts as a slightly leaking valve".
The Tesla valve is used in microfluidic applications and offers advantages such as scalability, durability, and ease of fabrication in a variety of materials.
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- "Tesla Valve" | 2021-08-12 | 100 Upvotes 40 Comments
- "A Tesla Valve" | 2019-12-18 | 197 Upvotes 42 Comments
π Jackson structured programming
Jackson structured programming (JSP) is a method for structured programming developed by British software consultant Michael A. Jackson and described in his 1975 book Principles of Program Design. The technique of JSP is to analyze the data structures of the files that a program must read as input and produce as output, and then produce a program design based on those data structures, so that the program control structure handles those data structures in a natural and intuitive way.
JSP describes structures (of both data and programs) using three basic structures β sequence, iteration, and selection (or alternatives). These structures are diagrammed as (in effect) a visual representation of a regular expression.
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- "Jackson structured programming" | 2021-08-12 | 106 Upvotes 69 Comments
π TSLAQ
TSLAQ is a loose, international collective of largely anonymous short-sellers, skeptics, and researchers who openly criticize Tesla, Inc. and its CEO, Elon Musk. The group primarily organizes on Twitter, often using the $TSLAQ cashtag, and Reddit to coordinate efforts and share news, opinions, and analysis about the company and its stock. Edward Niedermeyer, in his book Ludicrous: The Unvarnished Story of Tesla Motors (2019), establishes the doxxing of Lawrence Fossi, a Seeking Alpha writer and Tesla short seller who uses the pseudonym Montana Skeptic, in July 2018 as the catalyst for the formation of TSLAQ. The group was the subject of a Real Vision video which included interviews with prominent members @TESLACharts and @Paul91701736.
TSLAQ highlights what they claim to be a variety of dangerous, deceptive, unlawful and fraudulent business practices by Tesla. Regular criticisms include knowingly selling Model S cars with a design flaw that could cause fires, reselling defective "lemon" cars, performing stealth recalls and requiring customers to sign non-disclosure agreements for "goodwill" repairs, issuing over-the-air updates to cover-up a fire risk in their batteries, publishing misleading safety statistics, delivering cars with lower-performance hardware than promised, taking months to issue customers refunds, and selling a Full Self-Driving package with the promise 1 million "robotaxis" by the end of 2020 despite the technology not yet being available. TSLAQ has also criticized Tesla and Musk for their attempts to intimidate and silence whistleblowers who have spoken out against the company. In addition, the group has highlighted Tesla's history of environmental violations, disregard for workers' safety, and Musk's excessive compensation package. As financial media producer Demetri Kofinas put it, TSLAQ believes Musk "to be a carnival barker running the biggest fraud in corporate America."
On occasion, TSLAQ has exchanged online verbal hostilities with Tesla fans and Elon Musk, who once tweeted with a prominent member and also tweeted personal information of another. While explicitly an online group, off-line activities performed by subgroups include aerial reconnaissance and on-the-ground observations of parking lots used by Tesla for storage.
π Buridan's Ass
Buridan's ass is an illustration of a paradox in philosophy in the conception of free will. It refers to a hypothetical situation wherein an ass that is equally hungry and thirsty is placed precisely midway between a stack of hay and a pail of water. Since the paradox assumes the ass will always go to whichever is closer, it dies of both hunger and thirst since it cannot make any rational decision between the hay and water. A common variant of the paradox substitutes two identical piles of hay for the hay and water; the ass, unable to choose between the two, dies of hunger.
The paradox is named after the 14th-century French philosopher Jean Buridan, whose philosophy of moral determinism it satirizes. Although the illustration is named after Buridan, philosophers have discussed the concept before him, notably Aristotle, who used the example of a man equally hungry and thirsty, and Al-Ghazali, who used a man faced with the choice of equally good dates.
A version of this situation appears as metastability in digital electronics, when a circuit must decide between two states based on an input that is in itself undefined (neither zero nor one). Metastability becomes a problem if the circuit spends more time than it should in this "undecided" state, which is usually set by the speed of the clock the system is using.
π Richard Jewell
Richard Allensworth Jewell (born Richard White; December 17, 1962 β August 29, 2007) was an American security guard and law enforcement officer who alerted police during the Centennial Olympic Park bombing at the 1996 Summer Olympics in Atlanta, Georgia. For months afterwards he was suspected of planting the bomb, leading to adverse publicity that "came to symbolize the excesses of law enforcement and the news media."
While working as a security guard at the Olympic Park, Jewell discovered a backpack containing three pipe bombs on the park grounds. He alerted law enforcement and helped evacuate the area before the bomb exploded, probably saving many people from injury or death.
Initially hailed by the media as a hero, Jewell was soon considered a suspect by the FBI and local law enforcement based on scientific profiling. Though never charged, he underwent a "trial by media", which took a toll on his personal and professional life. Jewell was cleared as a suspect after 88 days of public scrutiny. Eric Rudolph eventually confessed and pleaded guilty to that bombing and other attacks. The media circus surrounding the investigation, which was leaked to the press, has been widely cited as an example of law enforcement and media excesses.
In recent years, Jewell's heroic legacy has been the subject of popular culture, including the 2019 film Richard Jewell, and the drama anthology series Manhunt.
π Penny Universities
English coffeehouses in the 17th and 18th centuries were public social places where men would meet for conversation and commerce. For the price of a penny, customers purchased a cup of coffee and admission. Travellers introduced coffee as a beverage to England during the mid-17th century; previously it had been consumed mainly for its supposed medicinal properties. Coffeehouses also served tea and hot chocolate as well as a light meal.
The historian Brian Cowan describes English coffeehouses as "places where people gathered to drink coffee, learn the news of the day, and perhaps to meet with other local residents and discuss matters of mutual concern." Topics like the Yellow Fever would also be discussed. The absence of alcohol created an atmosphere in which it was possible to engage in more serious conversation than in an alehouse. Coffeehouses also played an important role in the development of financial markets and newspapers.
Topics discussed included politics and political scandals, daily gossip, fashion, current events, and debates surrounding philosophy and the natural sciences. Historians often associate English coffeehouses, during the 17th and 18th centuries, with the intellectual and cultural history of the Age of Enlightenment: they were an alternate sphere, supplementary to the university. Political groups frequently used coffeehouses as meeting places.
π Trevor Moore, co-founder of Whitest Kids U Know, dies at 41
Trevor Paul Moore (April 4, 1980 β August 6, 2021) was an American comedian, actor, writer, director, producer, and musician. He was known as one of the founding members, alongside Sam Brown and Zach Cregger, of the New York City-based comedy troupe The Whitest Kids U' Know, who had their own sketch comedy series on IFC which ran for five seasons.
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- "Trevor Moore, co-founder of Whitest Kids U Know, dies at 41" | 2021-08-08 | 172 Upvotes 47 Comments