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🔗 Biology 🔗 Physics 🔗 Economics 🔗 Philosophy 🔗 Systems 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Epistemology

In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own. These properties or behaviors emerge only when the parts interact in a wider whole. For example, smooth forward motion emerges when a bicycle and its rider interoperate, but neither part can produce the behavior on their own.

Emergence plays a central role in theories of integrative levels and of complex systems. For instance, the phenomenon of life as studied in biology is an emergent property of chemistry, and psychological phenomena emerge from the neurobiological phenomena of living things.

In philosophy, theories that emphasize emergent properties have been called emergentism. Almost all accounts of emergentism include a form of epistemic or ontological irreducibility to the lower levels.

🔗 Books

Tsundoku (Japanese: 積ん読) is acquiring reading materials but letting them pile up in one's home without reading them.

The term originated in the Meiji era (1868–1912) as Japanese slang. It combines elements of tsunde-oku (積んでおく, to pile things up ready for later and leave) and dokusho (読書, reading books). It is also used to refer to books ready for reading later when they are on a bookshelf. As currently written, the word combines the characters for "pile up" (積) and the character for "read" (読).

The American author and bibliophile A. Edward Newton commented on a similar state.

🔗 Medicine 🔗 Psychology

Posttraumatic Embitterment Disorder (PTED) is defined as a pathological reaction to a negative life event, which those affected experienced as a grave insult, humiliation, betrayal, or injustice. Prevalent emotions of PTED are embitterment, anger, fury, and hatred, especially against the triggering stressor, often accompanied by fantasies of revenge. The disorder commences immediately and without time delay at the moment of the triggering event. If left untreated, the prognosis of PTED presents as rather unfavorable, since patients find themselves trapped in a vicious circle of strong negative emotions constantly intensifying one another and eventually leading into a self-destructive downward spiral. People affected by PTED are more likely to put fantasies of revenge into action, making them a serious threat to the stressor.

The concept of PTED as a distinct clinical disorder has been first described by the German psychiatrist and psychologist Michael Linden in 2003, who remains its most involved researcher. Even though it has been backed up by empirical research in the past years, it remains disputed as to whether embitterment should be included among psychological disorders. Therefore, PTED currently does not hold its own category in the ICD-10 but is categorized under F43.8 “Other reactions to severe stress”. It cannot be categorized as an adjustment disorder under F43.2, since “ordinary” adjustment disorders normally subside within six months, while PTED is much more likely to become chronical and last for much longer. A condition similar to PTED has already been described by Emil Kraepelin as early as 1915 by the name querulous paranoia as a form of traumatic neuroses, explicitly demarcating it from personality disorders.

🔗 Amateur radio

A QSL card is a written confirmation of either a two-way radiocommunication between two amateur radio or citizens band stations; a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station; or the reception of a two-way radiocommunication by a third party listener. A typical QSL card is the same size and made from the same material as a typical postcard, and most are sent through the mail as such.

QSL card derived its name from the Q code "QSL". A Q code message can stand for a statement or a question (when the code is followed by a question mark). In this case, 'QSL?' (note the question mark) means "Do you confirm receipt of my transmission?" while 'QSL' (without a question mark) means "I confirm receipt of your transmission."

🔗 Electronics

The Smith chart, invented by Phillip H. Smith (1905–1987), and T. Mizuhashi, is a graphical calculator or nomogram designed for electrical and electronics engineers specializing in radio frequency (RF) engineering to assist in solving problems with transmission lines and matching circuits. The Smith chart can be used to simultaneously display multiple parameters including impedances, admittances, reflection coefficients, ${\displaystyle S_{nn}\,}$ scattering parameters, noise figure circles, constant gain contours and regions for unconditional stability, including mechanical vibrations analysis. The Smith chart is most frequently used at or within the unity radius region. However, the remainder is still mathematically relevant, being used, for example, in oscillator design and stability analysis. While the use of paper Smith charts for solving the complex mathematics involved in matching problems has been largely replaced by software based methods, the Smith charts display is still the preferred method of displaying how RF parameters behave at one or more frequencies, an alternative to using tabular information. Thus most RF circuit analysis software includes a Smith chart option for the display of results and all but the simplest impedance measuring instruments can display measured results on a Smith chart display.

🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction

A Canticle for Leibowitz is a post-apocalyptic science fiction novel by American writer Walter M. Miller Jr., first published in 1959. Set in a Catholic monastery in the desert of the southwestern United States after a devastating nuclear war, the book spans thousands of years as civilization rebuilds itself. The monks of the Albertian Order of Leibowitz preserve the surviving remnants of man's scientific knowledge until the world is again ready for it.

The novel is a fixup of three short stories Miller published in The Magazine of Fantasy & Science Fiction that were inspired by the author's participation in the bombing of the monastery at the Battle of Monte Cassino during World War II. The book is considered one of the classics of science fiction and has never been out of print. Appealing to mainstream and genre critics and readers alike, it won the 1961 Hugo Award for best science fiction novel, and its themes of religion, recurrence, and church versus state have generated a significant body of scholarly research. A sequel, Saint Leibowitz and the Wild Horse Woman, was published posthumously in 1997.

🔗 Mathematics

Hilbert's twenty-fourth problem is a mathematical problem that was not published as part of the list of 23 problems known as Hilbert's problems but was included in David Hilbert's original notes. The problem asks for a criterion of simplicity in mathematical proofs and the development of a proof theory with the power to prove that a given proof is the simplest possible.

The 24th problem was rediscovered by German historian Rüdiger Thiele in 2000, noting that Hilbert did not include the 24th problem in the lecture presenting Hilbert's problems or any published texts. Hilbert's friends and fellow mathematicians Adolf Hurwitz and Hermann Minkowski were closely involved in the project but did not have any knowledge of this problem.

This is the full text from Hilbert's notes given in Rüdiger Thiele's paper. The section was translated by Rüdiger Thiele.

The 24th problem in my Paris lecture was to be: Criteria of simplicity, or proof of the greatest simplicity of certain proofs. Develop a theory of the method of proof in mathematics in general. Under a given set of conditions there can be but one simplest proof. Quite generally, if there are two proofs for a theorem, you must keep going until you have derived each from the other, or until it becomes quite evident what variant conditions (and aids) have been used in the two proofs. Given two routes, it is not right to take either of these two or to look for a third; it is necessary to investigate the area lying between the two routes. Attempts at judging the simplicity of a proof are in my examination of syzygies and syzygies [Hilbert misspelled the word syzygies] between syzygies (see Hilbert 42, lectures XXXII–XXXIX). The use or the knowledge of a syzygy simplifies in an essential way a proof that a certain identity is true. Because any process of addition [is] an application of the commutative law of addition etc. [and because] this always corresponds to geometric theorems or logical conclusions, one can count these [processes], and, for instance, in proving certain theorems of elementary geometry (the Pythagoras theorem, [theorems] on remarkable points of triangles), one can very well decide which of the proofs is the simplest. [Author's note: Part of the last sentence is not only barely legible in Hilbert's notebook but also grammatically incorrect. Corrections and insertions that Hilbert made in this entry show that he wrote down the problem in haste.]

🔗 Telecommunications

Procedure words or prowords are words or phrases limited to radio telephone procedure used to facilitate communication by conveying information in a condensed standard verbal format. Prowords are voice versions of the much older prosigns for Morse code first developed in the 1860s for Morse telegraphy, and their meaning is identical. The NATO communications manual ACP-125 contains the most formal and perhaps earliest modern (post-WW-II) glossary of procedure words, but its definitions have been adopted by many other organizations, including the United Nations Development Programme, the U.S. Coast Guard, the Rhode Island Department of Emergency Management, Civil Air Patrol, Military Auxiliary Radio System, and others.

Procedure words are one of several structured parts of radio voice procedures, including Brevity codes and Plain language radio checks. The vast majority of the brevity codes from the U.S. military's Multiservice tactical brevity code are inappropriate for any civilian use, owing to their focus on large weapons (missiles, etc.) and other war-related issues. However, a few are used frequently enough in media to be memorable, including ABORT, BOGEY, BANDIT, FEET WET, FEET DRY, NEGATIVE CONTACT, and NO JOY.

🔗 Apple Inc.

iPod Socks are a set of multi-colored cotton knit socks introduced by Apple Inc. in November 2004 for protection of iPods from damage during travel.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Free and open-source software

netcat (often abbreviated to nc) is a computer networking utility for reading from and writing to network connections using TCP or UDP. The command is designed to be a dependable back-end that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and investigation tool, since it can produce almost any kind of connection its user could need and has a number of built-in capabilities.

Its list of features includes port scanning, transferring files, and port listening, and it can be used as a backdoor.