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π Palmer Notation
Palmer notation (sometimes called the "Military System" and named for 19th-century American dentist Dr. Corydon Palmer from Warren, Ohio) is a dental notation (tooth numbering system). Despite the adoption of the FDI World Dental Federation notation (ISO 3950) in most of the world and by the World Health Organization, the Palmer notation continued to be the overwhelmingly preferred method used by orthodontists, dental students and practitioners in the United Kingdom as of 1998.
The notation was originally termed the Zsigmondy system after Hungarian dentist Adolf Zsigmondy, who developed the idea in 1861 using a Zsigmondy cross to record quadrants of tooth positions. Adult teeth were numbered 1 to 8, and the child primary dentition (also called deciduous, milk or baby teeth) were depicted with a quadrant grid using Roman numerals I, II, III, IV, V to number the teeth from the midline. Palmer changed this to A, B, C, D, E, which made it less confusing and less prone to errors in interpretation.
The Palmer notation consists of a symbol (ββΏ ββΎ) designating in which quadrant the tooth is found and a number indicating the position from the midline. Adult teeth are numbered 1 to 8, with deciduous (baby) teeth indicated by a letter A to E. Hence the left and right maxillary central incisor would have the same number, "1", but the right one would have the symbol "β" underneath it, while the left one would have "βΏ".
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- "Palmer Notation" | 2022-04-07 | 22 Upvotes 4 Comments
π Induced Demand Is Real
Induced demand β related to latent demand and generated demand β is the phenomenon that after supply increases, price declines and more of a good is consumed. This is entirely consistent with the economic theory of supply and demand; however, this idea has become important in the debate over the expansion of transportation systems, and is often used as an argument against increasing roadway traffic capacity as a cure for congestion. This phenomenon, more correctly called "induced traffic" or consumption of road capacity, may be a contributing factor to urban sprawl. City planner Jeff Speck has called induced demand "the great intellectual black hole in city planning, the one professional certainty that everyone thoughtful seems to acknowledge, yet almost no one is willing to act upon."
The inverse effect, or reduced demand, is also observed (see § Reduced demand).
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- "Induced Demand Is Real" | 2022-04-07 | 31 Upvotes 60 Comments
π Massacre in Korea by Pablo Picasso
Massacre in Korea (French: Massacre en CorΓ©e) is an expressionistic painting completed on 18 January 1951 by Pablo Picasso. It is Picasso's third anti-war painting and depicts a scene of a massacre of a group of naked women and children by a firing squad. It has been considered to be a condemnation of American intervention in the Korean War. The painting is exhibited in the MusΓ©e Picasso in Paris.
π The Dead HandβSoviet semi-autonomous nuclear command and control system
Dead Hand (Russian: Π‘ΠΈΡΡΠ΅ΠΌΠ° Β«ΠΠ΅ΡΠΈΠΌΠ΅ΡΡΒ», Systema "Perimetr", lit. "Perimeter" System, with the GRAU Index 15E601, Cyrillic: 15Π601), also known as Perimeter, is a Cold War-era automatic nuclear weapons-control system (similar in concept to the American AN/DRC-8 Emergency Rocket Communications System) that was used by the Soviet Union. The system remains in use in the post-Soviet Russian Federation. An example of fail-deadly and mutual assured destruction deterrence, it can automatically initiate the launch of the Russian intercontinental ballistic missiles (ICBMs) by sending a pre-entered highest-authority order from the General Staff of the Armed Forces, Strategic Missile Force Management to command posts and individual silos if a nuclear strike is detected by seismic, light, radioactivity, and pressure sensors even with the commanding elements fully destroyed. By most accounts, it is normally switched off and is supposed to be activated during times of crisis; however, it is said to remain fully functional and able to serve its purpose whenever it may be needed.
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- "The Dead HandβSoviet semi-autonomous nuclear command and control system" | 2022-04-04 | 73 Upvotes 90 Comments
π Bucha Massacre
In March 2022, a series of war crimes were committed by Russian occupation forces in the Ukrainian city of Bucha during the Battle of Bucha, following the Russian invasion of Ukraine. Ukrainian authorities said that more than 300 inhabitants of the town had been killed.
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- "Bucha Massacre" | 2022-04-04 | 57 Upvotes 61 Comments
π Molle
MOLLE (pronounced , similar in pronunciation to the name Molly) is an acronym for Modular Lightweight Load-carrying Equipment. It is used to define the current generation of load-bearing equipment and backpacks used by a number of NATO armed forces, especially the British Army and the United States Army.
The system's modularity is derived from the use of Pouch Attachment Ladder System (PALS) webbing equipment as rows of heavy-duty nylon stitched onto the vest to allow for the attachment of various compatible pouches and accessories. This method of attachment has become a de facto standard for modular tactical gear, replacing the All-purpose Lightweight Individual Carrying Equipment (ALICE) system used in the earliest modular vest systems (which is still in use with many police forces).
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- "Molle" | 2022-04-03 | 12 Upvotes 2 Comments
π Big Mac Index Manipulation
The Big Mac Index is a price index published by The Economist as an informal way of measuring the purchasing power parity (PPP) between two currencies and provides a test of the extent to which market exchange rates result in goods costing the same in different countries. It "seeks to make exchange-rate theory a bit more digestible."
The index, created in 1986, takes its name from the Big Mac, a hamburger sold at McDonald's restaurants.
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- "Big Mac Index Manipulation" | 2022-04-03 | 20 Upvotes 2 Comments
π IBM Parallel Sysplex
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems to share a workload for high performance and high availability.
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- "IBM Parallel Sysplex" | 2022-03-30 | 36 Upvotes 10 Comments
π The Scottish Play
The Scottish play and the Bard's play are euphemisms for William Shakespeare's Macbeth. The first is a reference to the play's Scottish setting, the second a reference to Shakespeareβs popular nickname. According to a theatrical superstition, called the Scottish curse, speaking the name Macbeth inside a theatre, other than as called for in the script while rehearsing or performing, will cause disaster. A variation of the superstition also forbids quoting lines from the play within a theatre except as part of an actual rehearsal or performance of the play.
Because of this superstition, the lead character is often referred to as the Scottish King or Scottish Lord. Lady Macbeth is often referred to as the Scottish Lady. Sometimes Mackers or MacB is used to avoid saying the name.
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- "The Scottish Play" | 2022-03-31 | 59 Upvotes 20 Comments
π Johns Hopkins Beast
The Johns Hopkins Beast was a mobile automaton, an early pre-robot, built in the 1960s at the Johns Hopkins University Applied Physics Laboratory. The machine had a rudimentary intelligence and the ability to survive on its own. As it wandered through the white halls of the laboratory, it would seek black wall outlets. When it found one it would plug in and recharge.
The robot was cybernetic. It did not use a computer. Its control circuitry consisted of dozens of transistors controlling analog voltages. It used photocell optics and sonar to navigate. The 2N404 transistors were used to create NOR logic gates that implemented the Boolean logic to tell it what to do when a specific sensor was activated. The 2N404 transistors were also used to create timing gates to tell it how long to do something. 2N1040 Power transistors were used to control the power to the motion treads, the boom, and the charging mechanism.
The original sensors in Mod I were physical touch only. The wall socket was detected by physical switches on the arm that followed the wall. Once detected, two electrical prongs were extended until they entered the wall socket and made the electrical connection to charge the vehicle. The stairway, doors, and pipes on the hall wall were also detected by physical switches and recognized by appropriate logic.
The sonar guidance system was developed for Mod I and improved for Mod II. It used two ultrasonic transducers to determine distance, location within the halls, and obstructions in its path. This provided "The Beast" with bat-like guidance. At this point, it could detect obstructions in the hallway, such as people in the hallway. Once an obstruction was detected, the Beast would slow down and then decide whether to stop or divert around the obstruction. It could also ultrasonically recognize the stairway and doorways to take appropriate action.
An optical guidance system was added to Mod II. This provided, among other capabilities, the ability to optically identify the black wall sockets that contrasted with the white wall.
The Hopkins Beast Autonomous Robot Mod II link below was written by Dr. Ronald McConnell, at that time a co-op student and one of the designers for Mod II.
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- "Johns Hopkins Beast" | 2022-03-30 | 198 Upvotes 48 Comments