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🔗 Computing

Logic Theorist is a computer program written in 1956 by Allen Newell, Herbert A. Simon and Cliff Shaw. It was the first program deliberately engineered to perform automated reasoning and is called "the first artificial intelligence program". It would eventually prove 38 of the first 52 theorems in Whitehead and Russell's Principia Mathematica, and find new and more elegant proofs for some.

🔗 Philosophy 🔗 Philosophy/Philosophical literature 🔗 Politics 🔗 Philosophy/Ancient philosophy 🔗 Philosophy/Ethics

The Nicomachean Ethics (; Ancient Greek: Ἠθικὰ Νικομάχεια, Ēthika Nikomacheia) is the name normally given to Aristotle's best-known work on ethics. The work, which plays a pre-eminent role in defining Aristotelian ethics, consists of ten books, originally separate scrolls, and is understood to be based on notes from his lectures at the Lyceum. The title is often assumed to refer to his son Nicomachus, to whom the work was dedicated or who may have edited it (although his young age makes this less likely). Alternatively, the work may have been dedicated to his father, who was also called Nicomachus.

The theme of the work is a Socratic question previously explored in the works of Plato, Aristotle's friend and teacher, of how men should best live. In his Metaphysics, Aristotle described how Socrates, the friend and teacher of Plato, had turned philosophy to human questions, whereas pre-Socratic philosophy had only been theoretical. Ethics, as now separated out for discussion by Aristotle, is practical rather than theoretical, in the original Aristotelian senses of these terms. In other words, it is not only a contemplation about good living, because it also aims to create good living. It is therefore connected to Aristotle's other practical work, the Politics, which similarly aims at people becoming good. Ethics is about how individuals should best live, while the study of politics is from the perspective of a law-giver, looking at the good of a whole community.

The Nicomachean Ethics is widely considered one of the most important historical philosophical works, and had an important impact upon the European Middle Ages, becoming one of the core works of medieval philosophy. It therefore indirectly became critical in the development of all modern philosophy as well as European law and theology. Many parts of the Nicomachean Ethics are well known in their own right, within different fields. In the Middle Ages, a synthesis between Aristotelian ethics and Christian theology became widespread, in Europe as introduced by Albertus Magnus. While various philosophers had influenced Christendom since its earliest times, in Western Europe Aristotle became "the Philosopher". The most important version of this synthesis was that of Thomas Aquinas. Other more "Averroist" Aristotelians such as Marsilius of Padua were controversial but also influential. (Marsilius is for example sometimes said to have influenced the controversial English political reformer Thomas Cromwell.)

A critical period in the history of this work's influence is at the end of the Middle Ages, and beginning of modernity, when several authors such as Francis Bacon and Thomas Hobbes, argued forcefully and largely successfully that the medieval Aristotelian tradition in practical thinking had become a great impediment to philosophy in their time. However, in more recent generations, Aristotle's original works (if not those of his medieval followers) have once again become an important source. More recent authors influenced by this work include Alasdair MacIntyre, G. E. M. Anscombe, Hans-Georg Gadamer, Martha Nussbaum and Avital Ronell.

🔗 Physics 🔗 Physics/Fluid Dynamics

A Feynman sprinkler, also referred to as a Feynman inverse sprinkler or as a reverse sprinkler, is a sprinkler-like device which is submerged in a tank and made to suck in the surrounding fluid. The question of how such a device would turn was the subject of an intense and remarkably long-lived debate.

A regular sprinkler has nozzles arranged at angles on a freely rotating wheel such that when water is pumped out of them, the resulting jets cause the wheel to rotate; both a Catherine wheel and the aeolipile ("Hero's engine") work on the same principle. A "reverse" or "inverse" sprinkler would operate by aspirating the surrounding fluid instead. The problem is now commonly associated with theoretical physicist Richard Feynman, who mentions it in his bestselling memoirs Surely You're Joking, Mr. Feynman! The problem did not originate with Feynman, nor did he publish a solution to it.

🔗 Computing

Secure Scuttlebutt (SSB) is a peer-to peer communication protocol, mesh network, and self-hosted social media ecosystem. Each user hosts their own content and the content of the peers they follow, which provides fault tolerance and eventual consistency. Messages are digitally signed and added to an append-only list of messages published by an author. SSB is primarily used for implementing distributed social networks, and utilizes cryptography to assure that content remains unforged as it is propagated through the network.

🔗 United States 🔗 Finance & Investment 🔗 Economics 🔗 Business

The Panic of 1907 – also known as the 1907 Bankers' Panic or Knickerbocker Crisis – was a financial crisis that took place in the United States over a three-week period starting in mid-October, when the New York Stock Exchange fell almost 50% from its peak the previous year. Panic occurred, as this was during a time of economic recession, and there were numerous runs on banks and trust companies. The 1907 panic eventually spread throughout the nation when many state and local banks and businesses entered bankruptcy. Primary causes of the run included a retraction of market liquidity by a number of New York City banks and a loss of confidence among depositors, exacerbated by unregulated side bets at bucket shops.

The panic was triggered by the failed attempt in October 1907 to corner the market on stock of the United Copper Company. When this bid failed, banks that had lent money to the cornering scheme suffered runs that later spread to affiliated banks and trusts, leading a week later to the downfall of the Knickerbocker Trust Company—New York City's third-largest trust. The collapse of the Knickerbocker spread fear throughout the city's trusts as regional banks withdrew reserves from New York City banks. Panic extended across the nation as vast numbers of people withdrew deposits from their regional banks. It is the 9th largest decline in U.S. stock market history.

The panic might have deepened if not for the intervention of financier J. P. Morgan, who pledged large sums of his own money, and convinced other New York bankers to do the same, to shore up the banking system. This highlighted the impotence of the nation's Independent Treasury system, which managed the nation's money supply yet was unable to inject liquidity back into the market. By November, the financial contagion had largely ended, only to be replaced by a further crisis. This was due to the heavy borrowing of a large brokerage firm that used the stock of Tennessee Coal, Iron and Railroad Company (TC&I) as collateral. Collapse of TC&I's stock price was averted by an emergency takeover by Morgan's U.S. Steel Corporation—a move approved by anti-monopolist president Theodore Roosevelt. The following year, Senator Nelson W. Aldrich, a leading Republican, established and chaired a commission to investigate the crisis and propose future solutions, leading to the creation of the Federal Reserve System.

🔗 Biology 🔗 Physics 🔗 Biophysics

Magnetosomes are membranous structures present in magnetotactic bacteria (MTB). They contain iron-rich magnetic particles that are enclosed within a lipid bilayer membrane. Each magnetosome can often contain 15 to 20 magnetite crystals that form a chain which acts like a compass needle to orient magnetotactic bacteria in geomagnetic fields, thereby simplifying their search for their preferred microaerophilic environments. Recent research has shown that magnetosomes are invaginations of the inner membrane and not freestanding vesicles. Magnetite-bearing magnetosomes have also been found in eukaryotic magnetotactic algae, with each cell containing several thousand crystals.

Overall, magnetosome crystals have high chemical purity, narrow size ranges, species-specific crystal morphologies and exhibit specific arrangements within the cell. These features indicate that the formation of magnetosomes is under precise biological control and is mediated biomineralization.

Magnetotactic bacteria usually mineralize either iron oxide magnetosomes, which contain crystals of magnetite (Fe₃O₄), or iron sulfide magnetosomes, which contain crystals of greigite (Fe₃S₄). Several other iron sulfide minerals have also been identified in iron sulfide magnetosomes—including mackinawite (tetragonal FeS) and a cubic FeS—which are thought to be precursors of Fe₃S₄. One type of magnetotactic bacterium present at the oxic-anoxic transition zone (OATZ) of the southern basin of the Pettaquamscutt River Estuary, Narragansett, Rhode Island, United States is known to produce both iron oxide and iron sulfide magnetosomes.

🔗 Physics 🔗 Books 🔗 Alternative Views 🔗 Color 🔗 Physics/Publications

Theory of Colours (German: Zur Farbenlehre) is a book by Johann Wolfgang von Goethe about the poet's views on the nature of colours and how these are perceived by humans. It was published in German in 1810 and in English in 1840. The book contains detailed descriptions of phenomena such as coloured shadows, refraction, and chromatic aberration.

The work originated in Goethe's occupation with painting and mainly exerted an influence on the arts (Philipp Otto Runge, J. M. W. Turner, the Pre-Raphaelites, Wassily Kandinsky). The book is a successor to two short essays entitled "Contributions to Optics".

Although Goethe's work was rejected by physicists, a number of philosophers and physicists have concerned themselves with it, including Thomas Johann Seebeck, Arthur Schopenhauer (see: On Vision and Colors), Hermann von Helmholtz, Rudolf Steiner, Ludwig Wittgenstein, Werner Heisenberg, Kurt Gödel, and Mitchell Feigenbaum.

Goethe's book provides a catalogue of how colour is perceived in a wide variety of circumstances, and considers Isaac Newton's observations to be special cases. Unlike Newton, Goethe's concern was not so much with the analytic treatment of colour, as with the qualities of how phenomena are perceived. Philosophers have come to understand the distinction between the optical spectrum, as observed by Newton, and the phenomenon of human colour perception as presented by Goethe—a subject analyzed at length by Wittgenstein in his comments on Goethe's theory in Remarks on Colour.

🔗 United States/U.S. Government 🔗 United States

Project COLDFEET was a 1962 Central Intelligence Agency (CIA) operation to extract intelligence from an abandoned Soviet Arctic drifting ice station. Due to the nature of its abandonment as the result of unstable ice, the retrieval of the operatives used the Fulton surface-to-air recovery system.

🔗 Japan 🔗 Japan/Culture 🔗 Textile Arts

Shibori (しぼり / 絞り) is a Japanese manual resist dyeing technique, which produces a number of different patterns on fabric.