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🔗 Spaceflight 🔗 Physics

The flyby anomaly is a discrepancy between current scientific models and the actual increase in speed (i.e. increase in kinetic energy) observed during a planetary flyby (usually of Earth) by a spacecraft. In multiple cases, spacecraft have been observed to gain greater speed than scientists had predicted, but thus far no convincing explanation has been found. This anomaly has been observed as shifts in the S-band and X-band Doppler and ranging telemetry. The largest discrepancy noticed during a flyby has been 13 mm/s.

🔗 United States 🔗 Aviation 🔗 Military history 🔗 Disaster management 🔗 Military history/Military aviation 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Aviation/Aviation accident 🔗 Iran 🔗 Military history/Maritime warfare

Iran Air Flight 655 was a scheduled passenger flight from Tehran to Dubai via Bandar Abbas that was shot down on 3 July 1988 by an SM-2MR surface-to-air missile fired from USS Vincennes, a guided-missile cruiser of the United States Navy. The aircraft, an Airbus A300, was destroyed and all 290 people on board were killed. The jet was hit while flying over Iran's territorial waters in the Persian Gulf, along the flight's usual route, shortly after departing Bandar Abbas International Airport, the flight's stopover location. The incident occurred during the final stages of the Iran–Iraq War, which had been continuing for nearly eight years. Vincennes had entered Iranian territory after one of its helicopters drew warning fire from Iranian speedboats operating within Iranian territorial limits.

The reason for the shootdown has been disputed between the governments of the two countries. According to the U.S., the Vincennes crew had incorrectly identified the Airbus as an attacking F-14 Tomcat, a U.S.-made jet fighter that had been part of the Iranian Air Force inventory since the 1970s. While the F-14s had been supplied to Iran in an air-to-air configuration, the Vincennes crew had been briefed that the Iranian F-14s were equipped with air-to-ground ordnance. Vincennes had made ten attempts to contact the aircraft both on military and on civilian frequencies, but had received no response. According to Iran, the cruiser negligently shot down the aircraft, which was transmitting IFF squawks in Mode III, a signal that identified it as a civilian aircraft, and not Mode II as used by Iranian military aircraft. The event generated a great deal of criticism of the United States. Some analysts blamed the captain of Vincennes, William C. Rogers III, for overly aggressive behavior in a tense and dangerous environment. In the days immediately following the incident, President Ronald Reagan issued a written diplomatic note to the Iranian government, expressing deep regret. However, the U.S. continued to insist that Vincennes was acting in self-defense in international waters.

In 1996, the governments of the U.S. and Iran reached a settlement at the International Court of Justice which included the statement "... the United States recognized the aerial incident of 3 July 1988 as a terrible human tragedy and expressed deep regret over the loss of lives caused by the incident ..." When President Ronald Reagan was directly asked if he considered the statement an apology, Reagan replied, "Yes." As part of the settlement, even though the U.S. government did not admit legal liability or formally apologize to Iran, it still agreed to pay US$61.8 million on an ex gratia basis in compensation to the families of the Iranian victims. The shootdown was the deadliest aviation disaster involving an Airbus A300.

🔗 Law

In contract law, a non-compete clause (often NCC), or covenant not to compete (CNC), is a clause under which one party (usually an employee) agrees not to enter into or start a similar profession or trade in competition against another party (usually the employer). Some courts refer to these as "restrictive covenants". As a contract provision, a CNC is bound by traditional contract requirements including the consideration doctrine.

The use of such clauses is premised on the possibility that upon their termination or resignation, an employee might begin working for a competitor or start a business, and gain competitive advantage by exploiting confidential information about their former employer's operations or trade secrets, or sensitive information such as customer/client lists, business practices, upcoming products, and marketing plans.

However, an over-broad CNC may prevent an employee from working elsewhere at all. English common law originally held any such constraint to be unenforceable under the public policy doctrine. Contemporary case law permits exceptions, but generally will only enforce CNCs to the extent necessary to protect the employer. Most jurisdictions in which such contracts have been examined by the courts have deemed CNCs to be legally binding so long as the clause contains reasonable limitations as to the geographical area and time period in which an employee of a company may not compete.

The extent to which non-compete clauses are legally allowed varies per jurisdiction. For example, the state of California in the United States invalidates non-compete-clauses for all but equity stakeholders in the sale of business interests.

🔗 Mathematics

The Karnaugh map (KM or K-map) is a method of simplifying Boolean algebra expressions. Maurice Karnaugh introduced it in 1953 as a refinement of Edward Veitch's 1952 Veitch chart, which actually was a rediscovery of Allan Marquand's 1881 logical diagram aka Marquand diagram but with a focus now set on its utility for switching circuits. Veitch charts are therefore also known as Marquand–Veitch diagrams, and Karnaugh maps as Karnaugh–Veitch maps (KV maps).

The Karnaugh map reduces the need for extensive calculations by taking advantage of humans' pattern-recognition capability. It also permits the rapid identification and elimination of potential race conditions.

The required Boolean results are transferred from a truth table onto a two-dimensional grid where, in Karnaugh maps, the cells are ordered in Gray code, and each cell position represents one combination of input conditions, while each cell value represents the corresponding output value. Optimal groups of 1s or 0s are identified, which represent the terms of a canonical form of the logic in the original truth table. These terms can be used to write a minimal Boolean expression representing the required logic.

Karnaugh maps are used to simplify real-world logic requirements so that they can be implemented using a minimum number of physical logic gates. A sum-of-products expression can always be implemented using AND gates feeding into an OR gate, and a product-of-sums expression leads to OR gates feeding an AND gate. Karnaugh maps can also be used to simplify logic expressions in software design. Boolean conditions, as used for example in conditional statements, can get very complicated, which makes the code difficult to read and to maintain. Once minimised, canonical sum-of-products and product-of-sums expressions can be implemented directly using AND and OR logic operators. Diagrammatic and mechanical methods for minimizing simple logic expressions have existed since at least the medieval times. More systematic methods for minimizing complex expressions began to be developed in the early 1950s, but until the mid to late 1980s the Karnaugh map was the most common used in practice.

🔗 Computing 🔗 Mathematics

The reflected binary code (RBC), also known just as reflected binary (RB) or Gray code after Frank Gray, is an ordering of the binary numeral system such that two successive values differ in only one bit (binary digit). The reflected binary code was originally designed to prevent spurious output from electromechanical switches. Today, Gray codes are widely used to facilitate error correction in digital communications such as digital terrestrial television and some cable TV systems.

🔗 Philosophy 🔗 Science Fiction 🔗 Literature 🔗 Philosophy/Epistemology

Sturgeon's revelation (as expounded by Theodore Sturgeon), referred to as Sturgeon's law, is an adage cited as "ninety percent of everything is crap." The sentence derives from quotations by Sturgeon, an American science fiction author and critic; although Sturgeon coined another adage he termed "Sturgeon's law", the "ninety percent crap" remark became Sturgeon's law.

The phrase was derived from Sturgeon's observation while science fiction was often derided for its low quality by critics, the majority of examples of works in other fields could equally be seen to be of low quality, and science fiction was thus no different in that regard from other art forms.

🔗 Film 🔗 Film/Filmmaking 🔗 Photography 🔗 Photography/History of photography

The Zone System is a photographic technique for determining optimal film exposure and development, formulated by Ansel Adams and Fred Archer. Adams described the Zone System as "[...] not an invention of mine; it is a codification of the principles of sensitometry, worked out by Fred Archer and myself at the Art Center School in Los Angeles, around 1939–40."

The technique is based on the late 19th century sensitometry studies of Hurter and Driffield. The Zone System provides photographers with a systematic method of precisely defining the relationship between the way they visualize the photographic subject and the final results. Although it originated with black-and-white sheet film, the Zone System is also applicable to roll film, both black-and-white and color, negative and reversal, and to digital photography.

🔗 Food and drink 🔗 Spirits 🔗 Food and drink/Beverages 🔗 James Bond

"Shaken, not stirred" is a catchphrase of Ian Fleming's fictional British Secret Service agent James Bond and describes his preference for the preparation of his martini cocktail.

The phrase first appears in the novel Diamonds Are Forever (1956), though Bond himself does not actually say it until Dr. No (1958), where his exact words are "shaken and not stirred." In the film adaptations of Fleming's novels, the phrase is first uttered by the villain, Dr. Julius No, when he offers the drink in Dr. No (1962), and it is not uttered by Bond himself (played by Sean Connery) until Goldfinger (1964). It is used in numerous Bond films thereafter with the notable exceptions of You Only Live Twice (1967), in which the drink is wrongly offered as "stirred, not shaken", to Bond's response "Perfect", and Casino Royale (2006) in which Bond, after losing millions of dollars in a game of poker, is asked if he wants his martini shaken or stirred and snaps, "Do I look like I give a damn?"

🔗 United States 🔗 Spaceflight 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 United States/Military history - U.S. military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Micronesia 🔗 Micronesia/Johnston Atoll

Starfish Prime was a July 9, 1962, high-altitude nuclear test conducted by the United States, a joint effort of the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency. It was launched from Johnston Atoll and was the largest nuclear test conducted in outer space and one of five conducted by the US in space.

A Thor rocket carrying a W49 thermonuclear warhead (designed by Los Alamos Scientific Laboratory) and a Mk. 2 reentry vehicle was launched from Johnston Atoll in the Pacific Ocean, about 900 miles (1,450 km) west-southwest of Hawaii. The explosion took place at an altitude of 250 miles (400 km), above a point 19 miles (31 km) southwest of Johnston Atoll. It produced a yield equivalent to 1.4 megatonnes of TNT. The explosion was about 10° above the horizon as seen from Hawaii, at 11 PM Hawaii time.

🔗 International relations 🔗 Philately 🔗 Amateur radio

An international reply coupon (IRC) is a coupon that can be exchanged for one or more postage stamps representing the minimum postage for an unregistered priority airmail letter of up to twenty grams sent to another Universal Postal Union (UPU) member country. IRCs are accepted by all UPU member countries.

UPU member postal services are obliged to exchange an IRC for postage, but are not obliged to sell them.

The purpose of the IRC is to allow a person to send someone in another country a letter, along with the cost of postage for a reply. If the addressee is within the same country, there is no need for an IRC because a self-addressed stamped envelope (SASE) or return postcard will suffice; but if the addressee is in another country an IRC removes the necessity of acquiring foreign postage or sending appropriate currency.