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🔗 Discworld

The technology depicted in Terry Pratchett's Discworld novels takes two forms: magical and mechanical. Nearly all technology early in the series is at least partially magical, but in more recent books, a form of industrial revolution takes place, with numerous purely mechanical inventions being introduced. In Thud! ancient 'devices' of undisclosed origin and great power were introduced; it is not clear whether these are magical, mechanical, both or neither. Time-travel technology, the exact nature of which is usually unclear, is used by the History Monks. Most Discworld technologies have real-world equivalents, in function if not form.

🔗 United States 🔗 Biography 🔗 Computer science 🔗 Telecommunications 🔗 Systems 🔗 Biography/science and academia 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Electronics 🔗 Systems/Systems theory 🔗 Telecommunications/Bell System 🔗 Cycling

Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, and cryptographer known as "the father of information theory". Shannon is noted for having founded information theory with a landmark paper, "A Mathematical Theory of Communication", that he published in 1948.

He is also well known for founding digital circuit design theory in 1937, when—as a 21-year-old master's degree student at the Massachusetts Institute of Technology (MIT)—he wrote his thesis demonstrating that electrical applications of Boolean algebra could construct any logical numerical relationship. Shannon contributed to the field of cryptanalysis for national defense during World War II, including his fundamental work on codebreaking and secure telecommunications.

🔗 Economics 🔗 Books 🔗 Psychology 🔗 Anthropology

IQ and the Wealth of Nations is a 2002 book by psychologist Richard Lynn and political scientist Tatu Vanhanen. The authors argue that differences in national income (in the form of per capita gross domestic product) are correlated with differences in the average national intelligence quotient (IQ). They further argue that differences in average national IQs constitute one important factor, but not the only one, contributing to differences in national wealth and rates of economic growth.

The book has drawn widespread criticism from other academics. Critiques have included questioning of the methodology used, the incompleteness of the data, and the conclusions drawn from the analysis. The 2006 book IQ and Global Inequality is a follow-up to IQ and the Wealth of Nations by the same authors.

🔗 Mathematics

The interesting number paradox is a semi-humorous paradox which arises from the attempt to classify every natural number as either "interesting" or "uninteresting". The paradox states that every natural number is interesting. The "proof" is by contradiction: if there exists a non-empty set of uninteresting natural numbers, there would be a smallest uninteresting number – but the smallest uninteresting number is itself interesting because it is the smallest uninteresting number, thus producing a contradiction.

In a discussion between the mathematicians G. H. Hardy and Srinivasa Ramanujan about interesting and uninteresting numbers, Hardy remarked that the number 1729 of the taxicab he had ridden seemed "rather a dull one", and Ramanujan immediately answered that it is interesting, being the smallest number that is the sum of two cubes in two different ways.

🔗 Telecommunications 🔗 Radio

Comfort noise (or comfort tone) is synthetic background noise used in radio and wireless communications to fill the artificial silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.

Some modern telephone systems (such as wireless and VoIP) use voice activity detection (VAD), a form of squelching where low volume levels are ignored by the transmitting device. In digital audio transmissions, this saves bandwidth of the communications channel by transmitting nothing when the source volume is under a certain threshold, leaving only louder sounds (such as the speaker's voice) to be sent. However, improvements in background noise reduction technologies can occasionally result in the complete removal of all noise. Although maximizing call quality is of primary importance, exhaustive removal of noise may not properly simulate the typical behavior of terminals on the PSTN system.

The result of receiving total silence, especially for a prolonged period, has a number of unwanted effects on the listener, including the following:

• the listener may believe that the transmission has been lost, and therefore hang up prematurely.
• the speech may sound "choppy" (see noise gate) and difficult to understand.
• the sudden change in sound level can be jarring to the listener.

To counteract these effects, comfort noise is added, usually on the receiving end in wireless or VoIP systems, to fill in the silent portions of transmissions with artificial noise. The noise generated is at a low but audible volume level, and can vary based on the average volume level of received signals to minimize jarring transitions.

In many VoIP products, users may control how VAD and comfort noise are configured, or disable the feature entirely.

As part of the RTP audio video profile, RFC 3389 defines a standard for distributing comfort noise information in VoIP systems.

A similar concept is that of sidetone, the effect of sound that is picked up by a telephone's mouthpiece and introduced (at low level) into the earpiece of the same handset, acting as feedback.

During the siege of Leningrad, the beat of a metronome was used as comfort noise on the Leningrad radio network, indicating that the network was still functioning.

Many radio stations broadcast birdsong, city-traffic or other atmospheric comfort noise during periods of deliberate silence. For example, in the UK, silence is observed on Remembrance Sunday, and London's quiet city ambiance is used. This is to reassure the listener that the station is on-air, but primarily to prevent silence detection systems at transmitters from automatically starting backup tapes of music (designed to be broadcast in the case of transmission link failure).

🔗 Mathematics

Zero is an even number. In other words, its parity—the quality of an integer being even or odd—is even. This can be easily verified based on the definition of "even": it is an integer multiple of 2, specifically 0 × 2. As a result, zero shares all the properties that characterize even numbers: for example, 0 is neighbored on both sides by odd numbers, any decimal integer has the same parity as its last digit—so, since 10 is even 0 will be even, and if y is even then y + x has the same parity as x—and x and 0 + x always have the same parity.

Zero also fits into the patterns formed by other even numbers. The parity rules of arithmetic, such as even − even = even, require 0 to be even. Zero is the additive identity element of the group of even integers, and it is the starting case from which other even natural numbers are recursively defined. Applications of this recursion from graph theory to computational geometry rely on zero being even. Not only is 0 divisible by 2, it is divisible by every power of 2, which is relevant to the binary numeral system used by computers. In this sense, 0 is the "most even" number of all.

Among the general public, the parity of zero can be a source of confusion. In reaction time experiments, most people are slower to identify 0 as even than 2, 4, 6, or 8. Some students of mathematics—and some teachers—think that zero is odd, or both even and odd, or neither. Researchers in mathematics education propose that these misconceptions can become learning opportunities. Studying equalities like 0 × 2 = 0 can address students' doubts about calling 0 a number and using it in arithmetic. Class discussions can lead students to appreciate the basic principles of mathematical reasoning, such as the importance of definitions. Evaluating the parity of this exceptional number is an early example of a pervasive theme in mathematics: the abstraction of a familiar concept to an unfamiliar setting.

🔗 United States 🔗 Biography 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Science Fiction 🔗 Biography/science and academia 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Biography/arts and entertainment 🔗 Chicago 🔗 United States/Massachusetts - Cape Cod and the Islands 🔗 United States/Indiana - Indianapolis

Kurt Vonnegut Jr. (; November 11, 1922 – April 11, 2007) was an American writer. In a career spanning over 50 years, Vonnegut published fourteen novels, three short story collections, five plays, and five works of non-fiction, with further collections being published after his death. He is most famous for his darkly satirical, best-selling novel Slaughterhouse-Five (1969).

Born and raised in Indianapolis, Indiana, Vonnegut attended Cornell University but dropped out in January 1943 and enlisted in the United States Army. As part of his training, he studied mechanical engineering at Carnegie Institute of Technology (now Carnegie Mellon University) and the University of Tennessee. He was then deployed to Europe to fight in World War II and was captured by the Germans during the Battle of the Bulge. He was interned in Dresden and survived the Allied bombing of the city by taking refuge in a meat locker of the slaughterhouse where he was imprisoned. After the war, Vonnegut married Jane Marie Cox, with whom he had three children. He later adopted his sister's three sons, after she died of cancer and her husband was killed in a train accident.

Vonnegut published his first novel, Player Piano, in 1952. The novel was reviewed positively but was not commercially successful. In the nearly 20 years that followed, Vonnegut published several novels that were only marginally successful, such as Cat's Cradle (1963) and God Bless You, Mr. Rosewater (1964). Vonnegut's breakthrough was his commercially and critically successful sixth novel, Slaughterhouse-Five. The book's anti-war sentiment resonated with its readers amidst the ongoing Vietnam War and its reviews were generally positive. After its release, Slaughterhouse-Five went to the top of The New York Times Best Seller list, thrusting Vonnegut into fame. He was invited to give speeches, lectures and commencement addresses around the country and received many awards and honors.

Later in his career, Vonnegut published several autobiographical essays and short-story collections, including Fates Worse Than Death (1991), and A Man Without a Country (2005). After his death, he was hailed as a morbidly comical commentator on the society in which he lived and as one of the most important contemporary writers. Vonnegut's son Mark published a compilation of his father's unpublished compositions, titled Armageddon in Retrospect. In 2017, Seven Stories Press published Complete Stories, a collection of Vonnegut's short fiction including five previously unpublished stories. Complete Stories was collected and introduced by Vonnegut friends and scholars Jerome Klinkowitz and Dan Wakefield. Numerous scholarly works have examined Vonnegut's writing and humor.

🔗 Internet 🔗 Computing 🔗 Computing/Software

The Gopher protocol is a communications protocol designed for distributing, searching, and retrieving documents in Internet Protocol networks. The design of the Gopher protocol and user interface is menu-driven, and presented an alternative to the World Wide Web in its early stages, but ultimately fell into disfavor, yielding to the Hypertext Transfer Protocol (HTTP). The Gopher ecosystem is often regarded as the effective predecessor of the World Wide Web.

The protocol was invented by a team led by Mark P. McCahill at the University of Minnesota. It offers some features not natively supported by the Web and imposes a much stronger hierarchy on the documents it stores. Its text menu interface is well-suited to computing environments that rely heavily on remote text-oriented computer terminals, which were still common at the time of its creation in 1991, and the simplicity of its protocol facilitated a wide variety of client implementations. More recent Gopher revisions and graphical clients added support for multimedia. Gopher was preferred by many network administrators for using fewer network resources than Web services.

Gopher's hierarchical structure provided a platform for the first large-scale electronic library connections. The Gopher protocol is still in use by enthusiasts, and although it has been almost entirely supplanted by the Web, a small population of actively-maintained servers remains.

The Theory of Interstellar Trade is a paper written in 1978 by the economist Paul Krugman. The paper was first published in March 2010 in the journal Economic Inquiry. He described the paper as something he wrote to cheer himself up when he was an "oppressed assistant professor" caught up in the academic rat race.

Krugman analyzed the question of

How should interest rates on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer traveling with the goods than to a stationary observer.

Krugman emphasized that in spite of its farcical subject matter, the economic analysis in the paper is correctly done. In his own words,

while the subject of this paper is silly, the analysis actually does make sense. This paper, then, is a serious analysis of a ridiculous subject, which is of course the opposite of what is usual in economics.

🔗 Philately 🔗 Czech Republic

The Prague pneumatic post (Czech: Pražská potrubní pošta) is the world's last preserved municipal pneumatic post system. It is an underground system of metal tubes under the wider centre of Prague, totaling about 55 kilometres (34 mi) in length. The system started service in 1889 and remained in use by the government, banks and the media until it was rendered inoperative by the August 2002 European floods.

Sold on by former owner Telefónica O2 Czech Republic after some limited attempts to make repairs, the system now belongs to businessman Zdeněk Dražil, who has announced plans to repair and reopen it as a working tourist attraction. As of 2012, however, it remains closed.