Random Articles (Page 3)
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π Small-World Experiment
The small-world experiment comprised several experiments conducted by Stanley Milgram and other researchers examining the average path length for social networks of people in the United States. The research was groundbreaking in that it suggested that human society is a small-world-type network characterized by short path-lengths. The experiments are often associated with the phrase "six degrees of separation", although Milgram did not use this term himself.
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- "Small-World Experiment" | 2020-03-15 | 50 Upvotes 3 Comments
π Mbone β Multicast over the Internet
Mbone (short for "multicast backbone") was an experimental backbone and virtual network built on top of the Internet for carrying IP multicast traffic on the Internet. It was developed in the early 1990s and required specialized hardware and software. Since the operators of most Internet routers have disabled IP multicast due to concerns regarding bandwidth tracking and billing, the Mbone was created to connect multicast-capable networks over the existing Internet infrastructure.
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- "Mbone β Multicast over the Internet" | 2015-02-21 | 11 Upvotes 4 Comments
π Electret
An electret (formed of as a portmanteau of electr- from "electricity" and -et from "magnet") is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fields, and is the electrostatic equivalent of a permanent magnet. Although Oliver Heaviside coined this term in 1885, materials with electret properties were already known to science and had been studied since the early 1700s. One particular example is the electrophorus, a device consisting of a slab with electret properties and a separate metal plate. The electrophorus was originally invented by Johan Carl Wilcke in Sweden and again by Alessandro Volta in Italy.
The name derives from "electron" and "magnet"; drawing analogy to the formation of a magnet by alignment of magnetic domains in a piece of iron. Historically, electrets were made by first melting a suitable dielectric material such as a polymer or wax that contains polar molecules, and then allowing it to re-solidify in a powerful electrostatic field. The polar molecules of the dielectric align themselves to the direction of the electrostatic field, producing a dipole electret with a permanent electrostatic bias. Modern electrets are usually made by embedding excess charges into a highly insulating dielectric, e.g. by means of an electron beam, corona discharge, injection from an electron gun, electric breakdown across a gap, or a dielectric barrier.
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- "Electret" | 2022-07-07 | 67 Upvotes 20 Comments
π List of oldest continuously inhabited cities
This is a list of present-day cities by the time period over which they have been continuously inhabited as a city. The age claims listed are generally disputed. Differences in opinion can result from different definitions of "city" as well as "continuous habitation" and historical evidence is often disputed. Caveats (and sources) to the validity of each claim are discussed in the "Notes" column.
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- "List of oldest continuously inhabited cities" | 2020-04-22 | 323 Upvotes 214 Comments
π Mike the Headless Chicken
Mike the Headless Chicken (April 20, 1945 β March 17, 1947), also known as Miracle Mike, was a Wyandotte chicken that lived for 18 months after his head had been cut off. Although the story was thought by many to be a hoax, the bird's owner took him to the University of Utah in Salt Lake City to establish the facts.
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- "Mike the Headless Chicken" | 2024-12-24 | 38 Upvotes 6 Comments
- "Mike the Headless Chicken" | 2015-11-11 | 52 Upvotes 14 Comments
π TP-82 Cosmonaut survival pistol
The TP-82 (Russian: Π’Π-82) was a triple-barrelled Soviet pistol that was carried by cosmonauts on space missions.
It was intended as a survival aid to be used after landings and before recovery in the Siberian wilderness. The TP-82 was the result of cosmonaut Alexei Leonov's concerns after being stranded in the Siberian wilderness when his Voskhod capsule malfunctioned. He feared that the 9mm pistol that was provided in the survival kit would be ineffective against the Siberian wildlife, namely bears and wolves.
The upper two shotgun barrels used 12.5Γ70Β mm ammunition (40 gauge), and the lower rifled barrel used 5.45Γ39mm ammunition developed for the AK-74 assault rifle. The TP-82 has a large lever on the left side of the receiver that opens the action and a small grip-safety under the trigger-guard that resembles a secondary trigger.
The pistol could be used for hunting, to defend against predators and for visible and audible distress signals. The detachable buttstock was also a machete that came with a canvas sheath. TP-82s were carried regularly on Soviet and Russian space missions from 1986 to 2007. They were part of the Soyuz Portable Emergency-Survival Kit (ΠΠΎΡΠΈΠΌΡΠΉ Π°Π²Π°ΡΠΈΠΉΠ½ΡΠΉ Π·Π°ΠΏΠ°Ρ, Nosimyi Avariynyi Zapas, NAZ). In 2007, the media reported that the remaining ammunition for the TP-82 had become unusable and that a regular semi-automatic pistol would be used on future missions.
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- "TP-82 Cosmonaut survival pistol" | 2019-09-05 | 174 Upvotes 74 Comments
π Lotus released Lotus 1-2-3 on January 26, 1983
Lotus 1-2-3 is a discontinued spreadsheet program from Lotus Software (later part of IBM). It was the first killer application of the IBM PC, was hugely popular in the 1980s, and significantly contributed to the success of IBM PC-compatibles in the business market.
The first spreadsheet, VisiCalc, had helped launch the Apple II as one of the earliest personal computers in business use. With IBM's entry into the market, VisiCalc was slow to respond, and when they did, they launched what was essentially a straight port of their existing system despite the greatly expanded hardware capabilities. Lotus's solution was marketed as a three-in-one integrated solution: it handled spreadsheet calculations, database functionality, and graphical charts, hence the name "1-2-3", though how much database capability the product actually had was debatable, given the sparse memory left over after launching 1-2-3. It quickly overtook VisiCalc, as well as Multiplan and SuperCalc, the two VisiCalc competitors.
Lotus 1-2-3 was the state-of-the-art spreadsheet and the standard throughout the 1980s and into the early 1990s, part of an unofficial set of three stand-alone office automation products that included dBase and WordPerfect, to build a complete business platform. Lotus Software had their own word processor named Lotus Manuscript, which was to some extent acclaimed in academia, but did not catch the interest of the business, nor the consumer market. With the acceptance of Windows 3.0 in 1990, the market for desktop software grew even more. None of the major spreadsheet developers had seriously considered the graphical user interface (GUI) to supplement their DOS offerings, and so they responded slowly to Microsoft's own GUI-based products Excel and Word. Lotus was surpassed by Microsoft in the early 1990s, and never recovered. IBM purchased Lotus in 1995, and continued to sell Lotus offerings, only officially ending sales in 2013.
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- "Lotus released Lotus 1-2-3 on January 26, 1983" | 2024-01-25 | 16 Upvotes 1 Comments
π All editions of Encarta are being discontinued (read about it on Wikipedia)
Microsoft Encarta was a digital multimedia encyclopedia published by Microsoft Corporation from 1993 to 2009. Originally sold on CD-ROM or DVD, it was also later available on the World Wide Web via an annual subscription β although later many articles could also be viewed free online with advertisements. By 2008, the complete English version, Encarta Premium, consisted of more than 62,000 articles, numerous photos and illustrations, music clips, videos, interactive content, timelines, maps, atlases and homework tools.
Microsoft published similar encyclopedias under the Encarta trademark in various languages, including German, French, Spanish, Dutch, Italian, Portuguese and Japanese. Localized versions contained contents licensed from national sources and more or less content than the full English version. For example, the Dutch version had content from the Dutch Winkler Prins encyclopedia.
In March 2009, Microsoft announced it was discontinuing both the Encarta disc and online versions. The MSN Encarta site was closed on October 31, 2009, in all countries except Japan, where it was closed on December 31, 2009. Microsoft continued to operate the Encarta online dictionary until 2011.
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- "All editions of Encarta are being discontinued (read about it on Wikipedia)" | 2009-03-30 | 15 Upvotes 3 Comments
π AN/PSQ-42
The AN/PSQ-42 Enhanced Night Vision Goggle-Binocular (ENVG-B) is a third-generation passive binocular night vision device developed for the United States Army by L3Harris. It combines dual tube image-intensifying (IΒ²) and thermal-imaging technologies into a single goggle, enabling vision in low-light conditions. The two methods can be used individually or simultaneously in a fused mode. The ENVG-B is intended to be issued to the dismounted combat arms soldiers within the Army's Brigade combat teams (BCT), and so far over 10,000 have been issued to several BCT's within the 1st Infantry Division, 2nd Infantry Division, 25th Infantry Division, 82nd Airborne Division and 101st Airborne Division. The US Marine Corps has also purchased 3,100 ENVG-B units.
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- "AN/PSQ-42" | 2023-12-06 | 54 Upvotes 42 Comments
π Fletcher's Checksum
The Fletcher checksum is an algorithm for computing a position-dependent checksum devised by John G. Fletcher (1934β2012) at Lawrence Livermore Labs in the late 1970s. The objective of the Fletcher checksum was to provide error-detection properties approaching those of a cyclic redundancy check but with the lower computational effort associated with summation techniques.
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- "Fletcher's Checksum" | 2018-10-02 | 87 Upvotes 11 Comments