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๐ Dujiangyan irrigation system
The Dujiangyan (Chinese: ้ฝๆฑๅ ฐ; pinyin: Dลซjiฤngyร n) is an ancient irrigation system in Dujiangyan City, Sichuan, China. Originally constructed around 256 BC by the State of Qin as an irrigation and flood control project, it is still in use today. The system's infrastructure develops on the Min River (Minjiang), the longest tributary of the Yangtze. The area is in the west part of the Chengdu Plain, between the Sichuan basin and the Tibetan plateau. Originally, the Min would rush down from the Min Mountains and slow down abruptly after reaching the Chengdu Plain, filling the watercourse with silt, thus making the nearby areas extremely prone to floods. Li Bing, then governor of Shu for the state of Qin, and his son headed the construction of the Dujiangyan, which harnessed the river using a new method of channeling and dividing the water rather than simply damming it. The water management scheme is still in use today to irrigate over 5,300 square kilometres (2,000ย sqย mi) of land in the region. The Dujiangyan, the Zhengguo Canal in Shaanxi and the Lingqu Canal in Guangxi are collectively known as the "three great hydraulic engineering projects of the Qin."
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- "Dujiangyan irrigation system" | 2014-04-22 | 66 Upvotes 12 Comments
๐ The deadliest school massacre in US history occurred in 1927
The Bath School disaster, also known as the Bath School massacre, was a series of violent attacks perpetrated by Andrew Kehoe on Mayย 18, 1927, in Bath Township, Michigan. The attacks killed 38ย elementary schoolchildren and 6ย adults, and injured at least 58ย other people. Prior to his timed explosives going off at the Bath Consolidated School building, Kehoe had murdered his wife, Nellie Price Kehoe, and firebombed his farm. Arriving at the site of the school explosion, Kehoe died when he detonated explosives concealed in his truck.
Kehoe, the 55-year-old school board treasurer, was angered by increased taxes and his defeat in the April 5, 1926, election for township clerk. He was thought by locals to have planned his "murderous revenge" after that public defeat. Kehoe had a reputation for difficulty on the school board and in personal dealings. In addition, he was notified that his mortgage was going to be foreclosed upon in June 1926. For much of the next year until May 1927, Kehoe purchased explosives. He secretly hid them on his property and under the school.
On May 18, 1927, Kehoe then set off almost simultaneous explosions at his farmstead and at the Bath Consolidated School. His explosives destroyed the farm's buildings and ripped through the north wing of the Bath Consolidated School building. As rescuers began working at the school, Kehoe drove up to the schoolyard and detonated dynamite inside his shrapnel-filled truck. The truck explosion killed Kehoe and several others nearby. Bystanders were injured. During the rescue and recovery efforts, searchers discovered an additional 500ย pounds (230ย kg) of unexploded dynamite and pyrotol in the south wing of the school that was set to explode at the same time as the initial explosions in the north wing; Kehoe had apparently intended to destroy the entire school and kill everyone in it.
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- "The deadliest school massacre in US history occurred in 1927" | 2012-12-17 | 19 Upvotes 5 Comments
๐ Banner Blindness
Banner blindness is a phenomenon in web usability where visitors to a website consciously or unconsciously ignore banner-like information. A broader term covering all forms of advertising is ad blindness, and the mass of banners that people ignore is called banner noise.
The term banner blindness was coined in 1998 as a result of website usability tests where a majority of the test subjects either consciously or unconsciously ignored information that was presented in banners. The information that was overlooked included both external advertisement banners and internal navigational banners, often called "quick links".
This does not, however, mean that banner ads do not influence viewers. Website viewers may not be consciously aware of an ad, but it does have an unconscious influence on their behavior. A banner's content affects both businesses and visitors of the site. Native advertising and social media are used to avoid banner blindness.
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- "Banner Blindness" | 2024-03-29 | 133 Upvotes 112 Comments
๐ Quine
A quine is a computer program which takes no input and produces a copy of its own source code as its only output. The standard terms for these programs in the computability theory and computer science literature are "self-replicating programs", "self-reproducing programs", and "self-copying programs".
A quine is a fixed point of an execution environment, when the execution environment is viewed as a function transforming programs into their outputs. Quines are possible in any Turing complete programming language, as a direct consequence of Kleene's recursion theorem. For amusement, programmers sometimes attempt to develop the shortest possible quine in any given programming language.
The name "quine" was coined by Douglas Hofstadter, in his popular science book Gรถdel, Escher, Bach, in honor of philosopher Willard Van Orman Quine (1908โ2000), who made an extensive study of indirect self-reference, and in particular for the following paradox-producing expression, known as Quine's paradox:
"Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation.
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- "Quine (computing)" | 2011-06-11 | 10 Upvotes 3 Comments
๐ Year Without a Summer
The year 1816 is known as the Year Without a Summer (also the Poverty Year and Eighteen Hundred and Froze To Death) because of severe climate abnormalities that caused average global temperatures to decrease by 0.4โ0.7ย ยฐC (0.72โ1.26ย ยฐF). This resulted in major food shortages across the Northern Hemisphere.
Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in April in the Dutch East Indies (now Indonesia). This eruption was the largest eruption in at least 1,300 years (after the hypothesized eruption causing the extreme weather events of 535โ536), and perhaps exacerbated by the 1814 eruption of Mayon in the Philippines.
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- "Year Without a Summer" | 2020-02-24 | 295 Upvotes 131 Comments
- "The Year Without a Summer" | 2018-11-17 | 14 Upvotes 1 Comments
๐ 2020 Stock Market Crash
The 2020 stock market crash is a global stock market crash that began on 20 February, 2020. On 12 February, the Dow Jones Industrial Average, the NASDAQ Composite, and S&P 500 Index all finished at record highs (while the NASDAQ and S&P 500 reached subsequent record highs on 19 February). From 24 to 28 February, stock markets worldwide reported their largest one-week declines since the 2008 financial crisis, thus entering a correction. Global markets into early March became extremely volatile, with large swings occurring in global markets. On 9ย March, most global markets reported severe contractions, mainly in response to the 2019โ20 coronavirus pandemic and an oil price war between Russia and the OPEC countries led by Saudi Arabia. This became colloquially known as Black Monday I, and at the time was the worst drop since the Great Recession in 2008.
Three days after Black Monday I there was another drop, Black Thursday, where stocks across Europe and North America fell more than 9%. Wall Street experienced its largest single-day percentage drop since Black Monday in 1987, and the FTSE MIB of the Borsa Italiana fell nearly 17%, becoming the worst-hit market during Black Thursday. Despite a temporary rally on 13ย March (with markets posting their best day since 2008), all three Wall Street indexes fell more than 12% when markets re-opened on 16ย March. At least one benchmark stock market index in all G7 countries and 14 of the G20 countries have been declared to be in bear markets.
As of March 2020, global stocks have seen a downturn of at least 25% during the crash, and 30% in most G20 nations. Goldman Sachs has warned that the US GDP will shrink 29% by the end of the 2nd quarter of 2020, and that unemployment may skyrocket to at least 9%. Australian Prime Minister Scott Morrison has called the looming economic crisis 'akin to the Great Depression'.
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- "2020 Stock Market Crash" | 2020-03-16 | 264 Upvotes 199 Comments
๐ Alternative 3
Alternative 3 is a television programme, broadcast once only in the United Kingdom in 1977, and later broadcast in Australia, Canada, and New Zealand, as a fictional hoax, an heir to Orson Welles' radio production of The War of the Worlds. Purporting to be an investigation into the UK's contemporary "brain drain", Alternative 3 uncovered a plan to make the Moon and Mars habitable in the event of climate change and a terminal environmental catastrophe on Earth.
The programme was originally meant to be broadcast on April Fools' Day, 1977. While its broadcast was delayed until 20 June, the credits explicitly date the film to 1 April. Alternative 3 ended with credits for the actors involved in the production and featured interviews with a fictitious American astronaut.
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- "Alternative 3" | 2021-07-12 | 37 Upvotes 13 Comments
๐ The Prague Pneumatic Post system (early mechanical networking)
The Prague pneumatic post (Czech: Praลพskรก potrubnรญ poลกta) is the world's last preserved municipal pneumatic post system. It is an underground system of metal tubes under the wider centre of Prague, totaling about 55 kilometres (34ย mi) in length. The system started service in 1889 and remained in use by the government, banks and the media until it was rendered inoperative by the August 2002 European floods.
Sold on by former owner Telefรณnica O2 Czech Republic after some limited attempts to make repairs, the system now belongs to businessman Zdenฤk Draลพil, who has announced plans to repair and reopen it as a working tourist attraction. As of 2012, however, it remains closed.
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- "The Prague Pneumatic Post system (early mechanical networking)" | 2009-08-12 | 18 Upvotes 3 Comments
๐ Josephson Voltage Standard
A Josephson voltage standard is a complex system that uses a superconducting integrated circuit chip operating at a temperature of 4ย K to generate stable voltages that depend only on an applied frequency and fundamental constants. It is an intrinsic standard in the sense that it does not depend on any physical artifact. It is the most accurate method to generate or measure voltage and, by international agreement in 1990, is the basis for voltage standards around the world.
๐ Sorcerer's Apprentice Syndrome
Sorcerer's Apprentice Syndrome (SAS) is a network protocol flaw in the original versions of TFTP. It was named after Goethe's poem "Der Zauberlehrling" (popularized by the "Sorcerer's Apprentice" segment of the animated film Fantasia), because the details of its operation closely resemble the disaster that befalls the sorcerer's apprentice: the problem resulted in an ever-growing replication of every packet in the transfer.
The problem occurred because of a known failure mode of the internetwork which, through a mistake on the part of the TFTP protocol designers, was not taken into account when the protocol was designed; the failure mode interacted with several details of the mechanisms of TFTP to produce SAS.
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- "Sorcerer's Apprentice Syndrome" | 2013-09-23 | 51 Upvotes 5 Comments