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π 1984 Rajneeshee bioterror attack
The 1984 Rajneeshee bioterror attack was the food poisoning of 751Β individuals in The Dalles, Oregon, through the deliberate contamination of salad bars at ten local restaurants with Salmonella. A group of prominent followers of Bhagwan Shree Rajneesh (later known as Osho) led by Ma Anand Sheela had hoped to incapacitate the voting population of the city so that their own candidates would win the 1984 Wasco County elections. The incident was the first and is the single largest bioterrorist attack in United States history.
Having previously gained political control of Antelope, Oregon, Rajneesh's followers, who were based in nearby Rajneeshpuram, sought election to two of the three seats on the Wasco County Circuit Court that were up for election in November 1984. Fearing they would not gain enough votes, some Rajneeshpuram officials decided to incapacitate voters in The Dalles, the largest population center in Wasco County. The chosen biological agent was Salmonella enterica Typhimurium, which was first delivered through glasses of water to two County Commissioners and then, on a larger scale, at salad bars and in salad dressing.
As a result of the attack, 751 people contracted salmonellosis, 45Β of whom were hospitalized, but none died. Although an initial investigation by the Oregon Public Health Division and the Centers for Disease Control did not rule out deliberate contamination, the agents and contamination were only confirmed a year later. On February 28, 1985, Congressman James H. Weaver gave a speech in the United States House of Representatives in which he "accused the Rajneeshees of sprinkling Salmonella culture on salad bar ingredients in eight restaurants".
At a press conference in September 1985, Rajneesh accused several of his followers of participation in this and other crimes, including an aborted plan in 1985 to assassinate a United States Attorney, and he asked state and federal authorities to investigate. Oregon Attorney General David B. Frohnmayer set up an interagency task force, composed of Oregon State Police and the Federal Bureau of Investigation, and executed search warrants in Rajneeshpuram. A sample of bacteria matching the contaminant that had sickened the town residents was found in a Rajneeshpuram medical laboratory. Two leading Rajneeshpuram officials were convicted on charges of attempted murder and served 29Β months of 20-year sentences in a minimum-security federal prison.
Discussed on
- "1984 Rajneeshee bioterror attack" | 2018-05-13 | 44 Upvotes 16 Comments
π Arecibo message
The Arecibo message is a 1974 interstellar radio message carrying basic information about humanity and Earth sent to globular star cluster M13. It was meant as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials.
The message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope in Puerto Rico on 16 November 1974. The message was aimed at the current location of M13 some 25,000 light years away because M13 was a large and close collection of stars that was available in the sky at the time and place of the ceremony. The message forms the image shown here when translated into graphics, characters, and spaces.
Discussed on
- "Arecibo message" | 2018-05-09 | 73 Upvotes 46 Comments
π Operation Ivy Bells
Operation Ivy Bells was a joint United States Navy, Central Intelligence Agency (CIA), and National Security Agency (NSA) mission whose objective was to place wire taps on Soviet underwater communication lines during the Cold War.
Discussed on
- "Operation Ivy Bells" | 2018-05-07 | 98 Upvotes 31 Comments
π List of screw drives
A screw drive is a system used to turn a screw. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. The following heads are categorized based on commonality, with some of the less-common drives being classified as "tamper-resistant".
Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00". These sizes do not necessarily describe a particular dimension of the drive shape, but rather are arbitrary designations.
Discussed on
- "List of screw drives" | 2018-05-07 | 303 Upvotes 255 Comments
π Zoopraxiscope
The zoΓΆpraxiscope (initially named zoographiscope and zoogyroscope) is an early device for displaying moving images and is considered an important predecessor of the movie projector. It was conceived by photographic pioneer Eadweard Muybridge in 1879 (and built for him by January 1880 to project his famous chronophotographic pictures in motion and thus prove that these were authentic). Muybridge used the projector in his public lectures from 1880 to 1895. The projector used 16" glass disks onto which Muybridge had an unidentified artist paint the sequences as silhouettes. This technique eliminated the backgrounds and enabled the creation of fanciful combinations and additional imaginary elements. Only one disk used photographic images, of a horse skeleton posed in different positions. A later series of 12" discs, made in 1892β1894, used outlines drawn by Erwin F. Faber that were printed onto the discs photographically, then colored by hand. These colored discs were probably never used in Muybridge's lectures. All images of the known 71 disks, including those of the photographic disk, were rendered in elongated form to compensate the distortion of the projection. The projector was related to other projecting phenakistiscopes and used some slotted metal shutter discs that were interchangeable for different picture disks or different effects on the screen. The machine was hand-cranked.
The device appears to have been one of the primary inspirations for Thomas Edison and William Kennedy Dickson's Kinetoscope, the first commercial film exhibition system. Images from all of the known seventy-one surviving zoopraxiscope discs have been reproduced in the book Eadweard Muybridge: The Kingston Museum Bequest (The Projection Box, 2004).
...it is the first apparatus ever used, or constructed, for synthetically demonstrating movements analytically photographed from life, and in its resulting effects is the prototype of the various instruments which, under a variety of names, are used for a similar purpose at the present day.
As stipulated in Muybridge's will the original machine and disks in his possession were left to Kingston upon Thames, where they are still kept in the Kingston Museum Muybridge Bequest Collection (except for four discs that are in other collections, including those of the Cinémathèque française and the National Technical Museum in Prague).
Muybridge also produced a series of 50 different paper 'Zoopraxiscope discs' (basically phenakistiscopes), again with pictures drawn by Erwin F. Faber. The discs were intended for sale at the 1893 World's Fair at Chicago, but seem to have sold very poorly and are quite rare. The discs were printed in black-and-white, with twelve different discs also produced as chromolithographed versions. Of the coloured versions only four different ones are known to still exist with a total of five or six extant copies.
π Kasparov versus the World
Kasparov versus the World was a game of chess played in 1999 over the Internet. Conducting the white pieces, Garry Kasparov faced the rest of the world in consultation, with the World Team moves to be decided by plurality vote. Over 50,000 people from more than 75 countries participated in the game.
The host and promoter of the match was the MSN Gaming Zone, with sponsorship from First USA bank. After 62 moves played over four months, Kasparov won the game. Contrary to expectations, the game produced a mixture of deep tactical and strategic ideas, and although Kasparov won, he admitted that he had never expended as much effort on any other game in his life. He later said, "It is the greatest game in the history of chess. The sheer number of ideas, the complexity, and the contribution it has made to chess make it the most important game ever played."
Discussed on
- "Kasparov versus the World" | 2018-04-28 | 256 Upvotes 60 Comments
- "In 1999, Kasparov played chess against 50000 people." | 2008-12-10 | 33 Upvotes 25 Comments
π Gravitation water vortex power plant
The gravitation water vortex power plant is a type of micro hydro vortex turbine system which is capable of converting energy in a moving fluid to rotational energy using a low hydraulic head of 0.7β3 metres (2Β ft 4Β inβ9Β ft 10Β in). The technology is based on a round basin with a central drain. Above the drain the water forms a stable line vortex which drives a water turbine.
It was first patented by Greek-Australian Lawyer & Inventor Paul Kouris in 1996, who was searching for a way to harness the power inherent in a vortex.
Later, Austrian Inventor Franz ZotlΓΆterer created a similar turbine while attempting to find a way to aerate water without an external power source.
Discussed on
- "Gravitation water vortex power plant" | 2018-04-21 | 227 Upvotes 80 Comments
π Burr conspiracy
The Burr conspiracy was a suspected treasonous cabal of US planters, politicians, and army officers in the early 19th century. The alleged cabal was led by Aaron Burr, the former Vice President of the United States (1801β1805). According to the accusations against him, his goal was to create an independent country in the center of North America including the Southwestern United States and parts of Mexico. Burr's version was that he intended to farm 40,000 acres (160Β km2) in the Texas Territory which had been leased to him by the Spanish Crown.
President Thomas Jefferson ordered Burr arrested and indicted for treason, despite a lack of firm evidence. Burr's true intentions remain unclear to historians; some claim that he intended to take parts of Texas and the Louisiana Purchase for himself, others, that he intended to conquer Mexico, and yet others, that he planned to conquer most of the North American continent. The number of men backing him is also unclear, with accounts varying from fewer than forty to over seven thousand. He was acquitted of treason, but the trial destroyed his already faltering political career.
Discussed on
- "Burr conspiracy" | 2018-04-20 | 70 Upvotes 23 Comments
π Fast inverse square root
Fast inverse square root, sometimes referred to as Fast InvSqrt() or by the hexadecimal constant 0x5F3759DF, is an algorithm that estimates β1ββx, the reciprocal (or multiplicative inverse) of the square root of a 32-bit floating-point number x in IEEE 754 floating-point format. This operation is used in digital signal processing to normalize a vector, i.e., scale it to length 1. For example, computer graphics programs use inverse square roots to compute angles of incidence and reflection for lighting and shading. The algorithm is best known for its implementation in 1999 in the source code of Quake III Arena, a first-person shooter video game that made heavy use of 3D graphics. The algorithm only started appearing on public forums such as Usenet in 2002 or 2003. At the time, it was generally computationally expensive to compute the reciprocal of a floating-point number, especially on a large scale; the fast inverse square root bypassed this step.
The algorithm accepts a 32-bit floating-point number as the input and stores a halved value for later use. Then, treating the bits representing the floating-point number as a 32-bit integer, a logical shift right by one bit is performed and the result subtracted from the number 0x5F3759DF, which is a floating point representation of an approximation of β2127. This results in the first approximation of the inverse square root of the input. Treating the bits again as a floating-point number, it runs one iteration of Newton's method, yielding a more precise approximation.
The algorithm was originally attributed to John Carmack, but an investigation showed that the code had deeper roots in both the hardware and software side of computer graphics. Adjustments and alterations passed through both Silicon Graphics and 3dfx Interactive, with Gary Tarolli's implementation for the SGI Indigo as the earliest known use. It is not known how the constant was originally derived, though investigation has shed some light on possible methods.
With subsequent hardware advancements, especially the x86 SSE instruction rsqrtss, this method is not generally applicable to modern computing, though it remains an interesting example both historically and for more limited machines.
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- "Fast inverse square root" | 2017-01-24 | 17 Upvotes 4 Comments
- "Fast inverse square root" | 2009-10-22 | 37 Upvotes 20 Comments