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🔗 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.

🔗 Psychology

The 'doorway effect' or ‘location updating effect’ is a replicable psychological phenomenon characterized by short-term memory loss when passing through a doorway or moving from one location to another. We tend to forget items of recent significance immediately after crossing a boundary and often forget what we were thinking about or planning on doing upon entering a different room. Research suggests that this phenomenon occurs both at literal boundaries (e.g., moving from one room to another via a door) and metaphorical boundaries (e.g., imagining traversing a doorway, or even when moving from one desktop window to another on a computer).

Memory is organized around specific events or episodes, such as attending a lecture or having a family meal, rather than being a continuous stream interrupted by sleep. This organization is called episodic memory, which involves receiving and storing information about events that are temporarily dated, along with their time and place relationships.

Numerous psychological studies have indicated that the external context, including the location where events occur, plays a significant role in how memories are separated. This context helps establish distinctions between different remembered events. Memories of events that happen in the environment we're currently in are easier to access compared to those from different places. As a result, when we experience spatial changes and move to a different location, it can act as a boundary marker that separates and categorizes our continuous flow of memories into distinct segments.

🔗 Computing 🔗 Computing/Software 🔗 Computer graphics

Xsnow is a software application that was originally created as a virtual greeting card for Macintosh systems in 1984. In 1993, the concept was ported to the X Window System as Xsnow, and was included on a number of Linux distributions in the late 1990s.

🔗 Computing 🔗 Computing/Computer hardware

Viewtron was an online service offered by Knight-Ridder and AT&T from 1983 to 1986. Patterned after the British Post Office's Prestel system, it started as a videotex service requiring users to have a special terminal, the AT&T Sceptre. As home computers became important in the marketplace, the development focus shifted to IBM, Apple, Commodore and other personal computers.

Viewtron differed from contemporary services like CompuServe and The Source by emphasizing news from The Miami Herald and Associated Press and e-commerce services from JCPenney and other merchants over computer-oriented services such as file downloads or online chat. Intended to be "the McDonald's of videotex," Viewtron was specifically targeted toward users who would be apprehensive about using a computer.

Viewtron also offered airline schedules from the Official Airline Guide (OAG), real estate research from Century 21, e-cards from Hallmark, product information from Consumer Reports, educational software from Scott Foresman, online auctions, financial services from American Express and EF Hutton, as well as limited online banking services as part of a research program into the uses and costs of banking online that included 20 US and Canadian banks.

At its height, Viewtron was operated in at least 15 cities by various newspaper companies. After six years of research and an investment reportedly in excess of $50 million, Viewtron never turned a profit, and, despite its developer's forecasts of breaking even in two years, Knight Ridder did not expect it ever would be profitable. AT&T had invested over $100 million in the project, but was forced to write off that investment as part of its court-ordered breakup. Viewtron closed on March 31, 1986, after an attempt by the Independent Commodore Users Group to buy the service failed.

A feature tying Viewtron to local newspapers was envisioned, with printed text instructing users how to access further information online, but it was never implemented.

In 2008, PCWorld magazine named Viewtron to a list of the biggest project failures in information technology (IT) history.

🔗 Cognitive science 🔗 Neuroscience

Sparse distributed memory (SDM) is a mathematical model of human long-term memory introduced by Pentti Kanerva in 1988 while he was at NASA Ames Research Center. It is a generalized random-access memory (RAM) for long (e.g., 1,000 bit) binary words. These words serve as both addresses to and data for the memory. The main attribute of the memory is sensitivity to similarity, meaning that a word can be read back not only by giving the original write address but also by giving one close to it, as measured by the number of mismatched bits (i.e., the Hamming distance between memory addresses).

SDM implements transformation from logical space to physical space using distributed data representation and storage, similarly to encoding processes in human memory. A value corresponding to a logical address is stored into many physical addresses. This way of storing is robust and not deterministic. A memory cell is not addressed directly. If input data (logical addresses) are partially damaged at all, we can still get correct output data.

The theory of the memory is mathematically complete and has been verified by computer simulation. It arose from the observation that the distances between points of a high-dimensional space resemble the proximity relations between concepts in human memory. The theory is also practical in that memories based on it can be implemented with conventional RAM-memory elements.

🔗 Physics 🔗 Physics/Acoustics

In acoustics, a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.

With tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception, the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.

🔗 Occupational Safety and Health

ISO 7010 is an International Organization for Standardization technical standard for graphical hazard symbols on hazard and safety signs, including those indicating emergency exits. It uses colours and principles set out in ISO 3864 for these symbols, and is intended to provide "safety information that relies as little as possible on the use of words to achieve understanding." It is distinct from the Globally Harmonized System of Classification and Labelling of Chemicals specified by the United Nations to standardise hazardous material classification and labelling.

As of August 2019, the latest version is ISO 7010:2019. This revision incorporates all previous corrigenda, as well as incorporates water safety signs and beach safety flags previously specified in (the now-withdrawn) ISO 20712.

🔗 Biography 🔗 Psychology 🔗 Cognitive science 🔗 Neuroscience 🔗 Birds

Alex (May 1976 – 6 September 2007) was a grey parrot and the subject of a thirty-year experiment by animal psychologist Irene Pepperberg, initially at the University of Arizona and later at Harvard University and Brandeis University. When Alex was about one year old, Pepperberg bought him at a pet shop. The name Alex was an acronym for avian language experiment, or avian learning experiment. He was compared to Albert Einstein and at two years old was correctly answering questions made for six-year-olds.

Before Pepperberg's work with Alex, it was widely believed in the scientific community that a large primate brain was needed to handle complex problems related to language and understanding; birds were not considered to be intelligent, as their only common use of communication was mimicking and repeating sounds to interact with each other. However, Alex's accomplishments supported the idea that birds may be able to reason on a basic level and use words creatively. Pepperberg wrote that Alex's intelligence was on a level similar to dolphins and great apes. She also reported that Alex seemed to show the intelligence of a five-year-old human, in some respects, and he had not even reached his full potential by the time he died. She believed that he possessed the emotional level of a two-year-old human at the time of his death.

🔗 Linguistics 🔗 Linguistics/Theoretical Linguistics

An agglutinative language is a type of synthetic language with morphology that primarily uses agglutination. Words may contain different morphemes to determine their meanings, but all of these morphemes (including stems and affixes) remain, in every aspect, unchanged after their unions. This results in generally more easily deducible word meanings if compared to fusional languages, which allow modifications in either or both the phonetics or spelling of one or more morphemes within a word. This usually results in a shortening of the word, or it provides easier pronunciation.

Agglutinative languages have generally one grammatical category per affix while fusional languages have multiple. The term was introduced by Wilhelm von Humboldt to classify languages from a morphological point of view. It is derived from the Latin verb agglutinare, which means "to glue together".

Non-agglutinative synthetic languages are fusional languages; morphologically, they combine affixes by "squeezing" them together, drastically changing them in the process, and joining several meanings in a single affix (for example, in the Spanish word comí "I ate", the suffix -í carries the meanings of first person, singular number, past tense, perfective aspect, indicative mood, active voice.) The term agglutinative is sometimes incorrectly used as a synonym for synthetic. Used in this way, the term embraces both fusional languages and inflected languages. The agglutinative and fusional languages are two ends of a continuum, with various languages falling more toward one or the other end. For example, Japanese is generally agglutinative, but displays fusion in otōto (弟, younger brother), from oto+hito (originally woto+pito), and in its non-affixing verb conjugations. A synthetic language may use morphological agglutination combined with partial usage of fusional features, for example in its case system (e.g., German, Dutch, and Persian).

Agglutinative languages tend to have a high rate of affixes or morphemes per word, and to be very regular, in particular with very few irregular verbs. For example, Japanese has very few irregular verbs – only two are significantly irregular, and there are only about a dozen others with only minor irregularity; Ganda has only one (or two, depending on how "irregular" is defined); while in the Quechua languages, all the ordinary verbs are regular. Korean has only ten irregular forms of conjugation except for the passive and causative conjugations. Georgian is an exception; it is highly agglutinative (with up to eight morphemes per word), but it has a significant number of irregular verbs with varying degrees of irregularity.

🔗 China 🔗 Geography 🔗 Maps 🔗 Japan 🔗 Japan/Geography and environment

Kunyu Wanguo Quantu, printed in China at the request of the Wanli Emperor during 1602 by the Italian Catholic missionary Matteo Ricci and Chinese collaborators, Mandarin Zhong Wentao and the technical translator, Li Zhizao, is the earliest known Chinese world map with the style of European maps. It has been referred to as the Impossible Black Tulip of Cartography, "because of its rarity, importance and exoticism". The map was crucial in expanding Chinese knowledge of the world. It was eventually exported to Korea then Japan and was influential there as well, though less so than Alenio's Zhifang Waiji.