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🔗 Climate change 🔗 China 🔗 Meteorology 🔗 Classical Greece and Rome 🔗 Greece 🔗 Rome 🔗 Ireland 🔗 Greece/Byzantine world 🔗 Peru

The extreme weather events of 535–536 were the most severe and protracted short-term episodes of cooling in the Northern Hemisphere in the last 2,000 years. The event is thought to have been caused by an extensive atmospheric dust veil, possibly resulting from a large volcanic eruption in the tropics or in Iceland. Its effects were widespread, causing unseasonable weather, crop failures, and famines worldwide.

🔗 Computer science

In computer architecture, Amdahl's law (or Amdahl's argument) is a formula which gives the theoretical speedup in latency of the execution of a task at fixed workload that can be expected of a system whose resources are improved. It is named after computer scientist Gene Amdahl, and was presented at the AFIPS Spring Joint Computer Conference in 1967.

Amdahl's law is often used in parallel computing to predict the theoretical speedup when using multiple processors. For example, if a program needs 20 hours to complete using a single thread, but a one-hour portion of the program cannot be parallelized, therefore only the remaining 19 hours (p = 0.95) of execution time can be parallelized, then regardless of how many threads are devoted to a parallelized execution of this program, the minimum execution time cannot be less than one hour. Hence, the theoretical speedup is limited to at most 20 times the single thread performance, ${\displaystyle \left({\dfrac {1}{1-p}}=20\right)}$.

🔗 United States/U.S. Government 🔗 United States 🔗 Biography 🔗 Philosophy 🔗 Philosophy/Logic 🔗 Biography/science and academia 🔗 Philosophy/Contemporary philosophy 🔗 Philosophy/Philosophers 🔗 United States/U.S. history

Gödel's Loophole is a "inner contradiction" in the Constitution of the United States which Austrian-German-American logician, mathematician, and analytic philosopher Kurt Gödel claimed to have discovered in 1947. The flaw would have allowed the American democracy to be legally turned into a dictatorship. Gödel told his friend Oskar Morgenstern about the existence of the flaw and Morgenstern told Albert Einstein about it at the time, but Morgenstern, in his recollection of the incident in 1971, never mentioned the exact problem as Gödel saw it. This has led to speculation about the precise nature of what has come to be called "Gödel's Loophole". It has been called "one of the great unsolved problems of constitutional law."

🔗 Ships 🔗 Egypt

The Yellow Fleet was the name given to a group of fifteen ships trapped in the Suez Canal (in the Great Bitter Lake section) from 1967 to 1975 as a result of the Israel-Egypt Six-Day War. Both ends of the canal had been blocked by the Egyptians with scuttled ships and other obstacles. The name Yellow Fleet derived from their yellow appearance as they were increasingly covered in a desert sand swept on board. After eight years, the only ships that were able to return to their home port under their own power were the West German ships Münsterland and Nordwind.

🔗 Computer science

The Hutter Prize is a cash prize funded by Marcus Hutter which rewards data compression improvements on a specific 1 GB English text file. Specifically, the prize awards 5000 euros for each one percent improvement (with 500,000 euros total funding) in the compressed size of the file enwik9, which is the larger of two files used in the Large Text Compression Benchmark; enwik9 is the first 1,000,000,000 characters of a specific version of English Wikipedia. The ongoing competition is organized by Hutter, Matt Mahoney, and Jim Bowery.

🔗 Public Art 🔗 Textile Arts 🔗 Graffiti

Yarn bombing (or yarnbombing) is a type of graffiti or street art that employs colourful displays of knitted or crocheted yarn or fibre rather than paint or chalk. It is also called wool bombing, yarn storming, guerrilla knitting, kniffiti, urban knitting, or graffiti knitting.

🔗 Philately

Letterlocking is the act of folding and securing a written message which could be on papyrus, parchment, or paper, so that it does not require an envelope or additional enclosure. It is a document security tradition which utilizes folding and cutting. The process dates to the 13th century in Western history, corresponding with the availability of flexible writing paper. Letterlocking uses small slits, tab, and holes placed directly into a letter, which combined with folding techniques are used to secure the letter ("letterpacket"), preventing reading the letter without breaking seals or slips, providing a means of tamper resistance. These folds and holes may be additionally secured with string and sealing wax. A Scottish diplomat in Italy, William Keith of Delny, sent letters to James VI of Scotland which would tear in two if not opened with care.

Intricate letterlocking works contain artistic elements, demonstrating more than a utilitarian purpose. While the use of sealing techniques may have been limited to ecclesiastic and the nobility, letterlocking was historically performed by all classes of writers. An individual could also be recognised by their personal technique of folding, as was the case with Jane Whorwood, of whose letter Charles I, imprisoned in Carisbrooke Castle on the Isle of Wight, wrote: "This Note [...] I know, by the fowldings [...] that it is written by [Mrs Whorwood]".

Letterlocking is also a discipline focusing on "the materially engineered security and privacy of letters, both as a technology and a historically evolving tradition."

🔗 Mathematics

The medieval Cistercian numerals, or "ciphers" in nineteenth-century parlance, were developed by the Cistercian monastic order in the early thirteenth century at about the time that Arabic numerals were introduced to northwestern Europe. They are more compact than Arabic or Roman numerals, with a single character able to indicate any integer from 1 to 9,999.

Digits are based on a horizontal or vertical stave, with the position of the digit on the stave indicating its place value (units, tens, hundreds or thousands). These digits are compounded on a single stave to indicate more complex numbers. The Cistercians eventually abandoned the system in favor of the Arabic numerals, but marginal use outside the order continued until the early twentieth century.

🔗 Australia 🔗 Amphibians and Reptiles 🔗 Academic Journals

The Wells and Wellington affair was a dispute about the publication of three papers in the Australian Journal of Herpetology in 1983 and 1985. The publication was established in 1981 as a peer-reviewed scientific journal focusing on the study of amphibians and reptiles (herpetology). Its first two issues were published under the editorship of Richard W. Wells, a first-year biology student at Australia's University of New England. Wells then ceased communicating with the journal's editorial board for two years before suddenly publishing three papers without peer review in the journal in 1983 and 1985. Coauthored by himself and high school teacher Cliff Ross Wellington, the papers reorganized the taxonomy of all of Australia's and New Zealand's amphibians and reptiles and proposed over 700 changes to the binomial nomenclature of the region's herpetofauna.

Members of the herpetological community reacted strongly to the pair's actions and eventually brought a case to the International Commission on Zoological Nomenclature to suppress the scientific names they had proposed. After four years of arguments, the commission opted not to vote on the case because it hinged largely on taxonomic arguments rather than nomenclatural ones, leaving some of Wells and Wellington's names available. The case's outcome highlighted the vulnerability to the established rules of biological nomenclature that desktop publishing presented. As of 2020, 24 of the specific names assigned by Wells and Wellington remained valid senior synonyms.

🔗 Canada 🔗 Astronomy 🔗 Canada/British Columbia

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is an interferometric radio telescope at the Dominion Radio Astrophysical Observatory in British Columbia, Canada which consists of four antennas consisting of 100 x 20 metre cylindrical parabolic reflectors (roughly the size and shape of snowboarding half-pipes) with 1024 dual-polarization radio receivers suspended on a support above them. The antenna receives radio waves from hydrogen in space at frequencies in the 400–800 MHz range. The telescope's low-noise amplifiers are built with components adapted from the cellphone industry and its data are processed using a custom-built FPGA electronic system and 1000-processor high-performance GPGPU cluster. The telescope has no moving parts and observes half of the sky each day as the Earth turns. It has also turned out to be a superior instrument for observing the recently discovered phenomenon of fast radio bursts (FRBs).

CHIME is a partnership between the University of British Columbia, McGill University, the University of Toronto and the Canadian National Research Council's Dominion Radio Astrophysical Observatory. A first light ceremony was held on 7 September 2017 to inaugurate the commissioning phase.