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πŸ”— The Society in Dedham for Apprehending Horse Thieves

πŸ”— Equine

The Society in Dedham for Apprehending Horse Thieves is the "oldest continually existing horse thief apprehending organization in the United States, and one of Dedham's most venerable social organizations." Since its founding there have been more than 10,000 members including heads of state, Supreme Court justices, governors, popes, professors, generals, and other notables.

At one time membership of the "ancient and well known society" was limited to "the pillars of society" and the "very flower and pick of the vigor, manhood and rising youth of the vicinity." It has also been said that "for sheer whimsy, the Society... is without peer." Today it is a tax exempt non-profit social organization that continues to meet "just in case."

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πŸ”— Fire balloon

πŸ”— Aviation πŸ”— Military history πŸ”— Military history/Military aviation πŸ”— Military history/Military science, technology, and theory πŸ”— Military history/Weaponry

An incendiary balloon (or balloon bomb) is a balloon inflated with a lighter than air gas such as hot air, hydrogen, or helium, that has a bomb, incendiary device, or Molotov cocktail attached. The balloon is carried by the prevailing winds to the target area, where it falls or releases its payload.

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πŸ”— DCF77

πŸ”— Germany πŸ”— Time πŸ”— Radio Stations

DCF77 is a German longwave time signal and standard-frequency radio station. It started service as a standard-frequency station on 1 January 1959. In June 1973 date and time information was added. Its primary and backup transmitter are located at 50Β°0β€²56β€³N 9Β°00β€²39β€³E in Mainflingen, about 25Β km south-east of Frankfurt am Main, Germany. The transmitter generates a nominal power of 50Β kW, of which about 30 to 35Β kW can be radiated via a T-antenna.

DCF77 is controlled by the Physikalisch-Technische Bundesanstalt (PTB), Germany's national physics laboratory and transmits in continuous operation (24 hours). It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the PTB. With Media Broadcast GmbH, a temporal transmission availability of at least 99.7% per year or under 26.28 hours of annual downtime has been agreed upon. Most service interruptions are short-term disconnections of under two minutes. Longer lasting transmission service interruptions are generally caused by strong winds, freezing rain or snow-induced T-antenna movement. This manifests itself in electrical detuning of the antenna resonance circuit and hence a measurable phase modulation of the received signal. When the maladjustment is too large, the transmitter is taken out of service temporarily. In the year 2002, almost 99.95% availability, or just over 4.38 hours of downtime, was realized. The timestamp sent is either in Coordinated Universal Time (UTC)+1 or UTC+2 depending on daylight saving time.

The highly accurate 77.5Β kHz (approximately 3868.3Β m wavelength) carrier signal is generated from local atomic clocks that are linked with the German master clocks at the PTB in Braunschweig. The DCF77 time signal is used for the dissemination of the German national legal time to the public.

Radio clocks and watches have been very popular in Europe since the late 1980s and, in mainland Europe, most of them use the DCF77 signal to set their time automatically. Further industrial time-keeping systems at railway stations, in the field of telecommunication and information technology, and at radio and TV stations are radio-controlled by DCF77 as well as tariff change-over clocks of energy supply companies and clocks in traffic-light facilities.

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  • "DCF77" | 2021-06-30 | 67 Upvotes 37 Comments

πŸ”— Post-quantum cryptography: just in case

πŸ”— Computing πŸ”— Computing/Software πŸ”— Computing/Computer science πŸ”— Cryptography πŸ”— Cryptography/Computer science πŸ”— Computing/Computer Security

Post-quantum cryptography (sometimes referred to as quantum-proof, quantum-safe or quantum-resistant) refers to cryptographic algorithms (usually public-key algorithms) that are thought to be secure against an attack by a quantum computer. As of 2019, this is not true for the most popular public-key algorithms, which can be efficiently broken by a sufficiently strong quantum computer. The problem with currently popular algorithms is that their security relies on one of three hard mathematical problems: the integer factorization problem, the discrete logarithm problem or the elliptic-curve discrete logarithm problem. All of these problems can be easily solved on a sufficiently powerful quantum computer running Shor's algorithm. Even though current, publicly known, experimental quantum computers lack processing power to break any real cryptographic algorithm, many cryptographers are designing new algorithms to prepare for a time when quantum computing becomes a threat. This work has gained greater attention from academics and industry through the PQCrypto conference series since 2006 and more recently by several workshops on Quantum Safe Cryptography hosted by the European Telecommunications Standards Institute (ETSI) and the Institute for Quantum Computing.

In contrast to the threat quantum computing poses to current public-key algorithms, most current symmetric cryptographic algorithms and hash functions are considered to be relatively secure against attacks by quantum computers. While the quantum Grover's algorithm does speed up attacks against symmetric ciphers, doubling the key size can effectively block these attacks. Thus post-quantum symmetric cryptography does not need to differ significantly from current symmetric cryptography. See section on symmetric-key approach below.

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πŸ”— Cyclorama

πŸ”— Visual arts

A cyclorama is a panoramic image on the inside of a cylindrical platform, designed to give viewers standing in the middle of the cylinder a 360Β° view, and also a building designed to show a panoramic image. The intended effect is to make viewers, surrounded by the panoramic image, feel as if they were standing in the midst of the place depicted in the image.

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πŸ”— Mercantilism

πŸ”— History πŸ”— Economics πŸ”— Politics πŸ”— Trade πŸ”— Politics/Libertarianism

Mercantilism is a nationalist economic policy that is designed to maximize the exports and minimize the imports of an economy. In other words, it seeks to maximize the accumulation of resources within the country and use those resources for one-sided trade.

The concept aims to reduce a possible current account deficit or reach a current account surplus, and it includes measures aimed at accumulating monetary reserves by a positive balance of trade, especially of finished goods. Historically, such policies may have contributed to war and motivated colonial expansion. Mercantilist theory varies in sophistication from one writer to another and has evolved over time.

Mercantilism promotes government regulation of a nation's economy for the purpose of augmenting and bolstering state power at the expense of rival national powers. High tariffs, especially on manufactured goods, were almost universally a feature of mercantilist policy. Before it fell into decline, mercantilism was dominant in modernized parts of Europe and some areas in Africa from the 16th to the 19th centuries, a period of proto-industrialization. Some commentators argue that it is still practised in the economies of industrializing countries in the form of economic interventionism.

With the efforts of supranational organizations such as the World Trade Organization to reduce tariffs globally, non-tariff barriers to trade have assumed a greater importance in neomercantilism.

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πŸ”— Peto's Paradox

πŸ”— Physiology πŸ”— Molecular Biology πŸ”— Physiology/cell πŸ”— Molecular Biology/Molecular and Cell Biology

Peto's paradox is an observation that at the species level, the incidence of cancer does not appear to correlate with the number of cells in an organism. For example, the incidence of cancer in humans is much higher than the incidence of cancer in whales, despite whales having more cells than humans. If the probability of carcinogenesis were constant across cells, one would expect whales to have a higher incidence of cancer than humans. Peto's paradox is named after English statistician and epidemiologist Richard Peto, who first observed the connection.

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πŸ”— 6174

The number 6174 is known as Kaprekar's constant after the Indian mathematician D. R. Kaprekar. This number is renowned for the following rule:

  1. Take any four-digit number, using at least two different digits (leading zeros are allowed).
  2. Arrange the digits in descending and then in ascending order to get two four-digit numbers, adding leading zeros if necessary.
  3. Subtract the smaller number from the bigger number.
  4. Go back to step 2 and repeat.

The above process, known as Kaprekar's routine, will always reach its fixed point, 6174, in at most 7 iterations. Once 6174 is reached, the process will continue yielding 7641 – 1467 = 6174. For example, choose 1459:

The only four-digit numbers for which Kaprekar's routine does not reach 6174 are repdigits such as 1111, which give the result 0000 after a single iteration. All other four-digit numbers eventually reach 6174 if leading zeros are used to keep the number of digits at 4. For numbers with three identical numbers and a fourth number that is one number higher or lower (such as 2111), it is essential to treat 3-digit numbers with a leading zero; for example: 2111 – 1112 = 0999; 9990 – 999 = 8991; 9981 – 1899 = 8082; 8820 – 288 = 8532; 8532 – 2358 = 6174.

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  • "6174" | 2024-01-16 | 511 Upvotes 102 Comments

πŸ”— The Scottish Play

πŸ”— Scotland πŸ”— Theatre πŸ”— Shakespeare

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 Shakespeare’s 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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πŸ”— Ruby (Programming Language)

πŸ”— Computing πŸ”— Computer science πŸ”— Computing/Software πŸ”— Computing/Free and open-source software

Ruby is an interpreted, high-level, general-purpose programming language which supports multiple programming paradigms. It was designed with an emphasis on programming productivity and simplicity. In Ruby, everything is an object, including primitive data types. It was developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.

Ruby is dynamically typed and uses garbage collection and just-in-time compilation. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, BASIC, Java and Lisp.

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