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🔗 Mathematics 🔗 Astronomy

Gauss's Pythagorean right triangle proposal is an idea attributed to Carl Friedrich Gauss for a method to signal extraterrestrial beings by constructing an immense right triangle and three squares on the surface of the Earth. The shapes would be a symbolic representation of the Pythagorean theorem, large enough to be seen from the Moon or Mars.

Although credited in numerous sources as originating with Gauss, with exact details of the proposal set out, the specificity of detail, and even whether Gauss made the proposal, have been called into question. Many of the earliest sources do not actually name Gauss as the originator, instead crediting a "German astronomer" or using other nonspecific descriptors, and in some cases naming a different author entirely. The details of the proposal also change significantly upon different retellings. Nevertheless, Gauss's writings reveal a belief and interest in finding a method to contact extraterrestrial life, and that he did, at the least, propose using amplified light using a heliotrope, his own 1818 invention, to signal supposed inhabitants of the Moon.

🔗 Computing 🔗 Computing/Computer hardware

The Dadda multiplier is a hardware binary multiplier design invented by computer scientist Luigi Dadda in 1965. It uses a selection of full and half adders to sum the partial products in stages (the Dadda tree or Dadda reduction) until two numbers are left. The design is similar to the Wallace multiplier, but the different reduction tree reduces the required number of gates (for all but the smallest operand sizes) and makes it slightly faster (for all operand sizes).

Dadda and Wallace multipliers have the same three steps for two bit strings ${\displaystyle w_{1}}$ and ${\displaystyle w_{2}}$ of lengths ${\displaystyle \ell _{1}}$ and ${\displaystyle \ell _{2}}$ respectively:

1. Multiply (logical AND) each bit of ${\displaystyle w_{1}}$, by each bit of ${\displaystyle w_{2}}$, yielding ${\displaystyle \ell _{1}\cdot \ell _{2}}$ results, grouped by weight in columns
2. Reduce the number of partial products by stages of full and half adders until we are left with at most two bits of each weight.
3. Add the final result with a conventional adder.

As with the Wallace multiplier, the multiplication products of the first step carry different weights reflecting the magnitude of the original bit values in the multiplication. For example, the product of bits ${\displaystyle a_{n}b_{m}}$ has weight ${\displaystyle n+m}$.

Unlike Wallace multipliers that reduce as much as possible on each layer, Dadda multipliers attempt to minimize the number of gates used, as well as input/output delay. Because of this, Dadda multipliers have a less expensive reduction phase, but the final numbers may be a few bits longer, thus requiring slightly bigger adders.

🔗 Technology 🔗 Linguistics 🔗 Japan 🔗 Japan/Science and technology 🔗 Japan/CJKV

Mojibake (Japanese: 文字化け; IPA: [mod͡ʑibake]) is the garbled text that is the result of text being decoded using an unintended character encoding. The result is a systematic replacement of symbols with completely unrelated ones, often from a different writing system.

This display may include the generic replacement character ("�") in places where the binary representation is considered invalid. A replacement can also involve multiple consecutive symbols, as viewed in one encoding, when the same binary code constitutes one symbol in the other encoding. This is either because of differing constant length encoding (as in Asian 16-bit encodings vs European 8-bit encodings), or the use of variable length encodings (notably UTF-8 and UTF-16).

Failed rendering of glyphs due to either missing fonts or missing glyphs in a font is a different issue that is not to be confused with mojibake. Symptoms of this failed rendering include blocks with the code point displayed in hexadecimal or using the generic replacement character. Importantly, these replacements are valid and are the result of correct error handling by the software.

🔗 Norse history and culture

In Norse mythology, Ragnarök ( (listen); Old Norse: Ragnarǫk) is a series of events, including a great battle, foretelling the death of numerous great figures (including the gods Odin, Thor, Týr, Freyr, Heimdallr, and Loki), natural disasters, and the submersion of the world in water. After these events, the world will rise again, cleansed and fertile, the surviving and returning gods will meet and the world will be repopulated by two human survivors. Ragnarök is an important event in Norse mythology and has been the subject of scholarly discourse and theory in the history of Germanic studies.

The event is attested primarily in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda, written in the 13th century by Snorri Sturluson. In the Prose Edda and in a single poem in the Poetic Edda, the event is referred to as Ragnarøkkr (Old Norse for 'Twilight of the Gods'), a usage popularised by 19th-century composer Richard Wagner with the title of the last of his Der Ring des Nibelungen operas, Götterdämmerung (1876), which is "Twilight of the Gods" in German.

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

High Efficiency Image File Format (HEIF) is a container format for storing individual digital images and image sequences. The standard covers multimedia files that can also include other media streams, such as timed text, audio and video.

HEIF can store images encoded with multiple coding formats, for example both SDR and HDR images. HEVC is an image and video encoding format and the default image codec used with HEIF. HEIF files containing HEVC-encoded images are also known as HEIC files. Such files require less storage space than the equivalent quality JPEG.

HEIF files are a special case of the ISO Base Media File Format (ISOBMFF, ISO/IEC 14496-12), first defined in 2001 as a shared part of MP4 and JPEG 2000. Introduced in 2015, it was developed by the Moving Picture Experts Group (MPEG) and is defined as Part 12 within the MPEG-H media suite (ISO/IEC 23008-12).

HEIF was adopted by Apple in 2017 with the introduction of iOS 11.

🔗 Taxation

This article lists countries alphabetically, with total tax revenue as a percentage of gross domestic product (GDP) for the listed countries. The tax percentage for each country listed in the source has been added to the chart.

🔗 United States/U.S. Government 🔗 United States 🔗 International relations 🔗 Germany 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Europe 🔗 Italy 🔗 Sociology 🔗 Organizations 🔗 Military history/German military history 🔗 Military history/French military history 🔗 Military history/Cold War 🔗 Cold War 🔗 Military history/Dutch military history 🔗 Rome 🔗 European history 🔗 Military history/Italian military history 🔗 Military history/European military history 🔗 Military history/British military history 🔗 Military history/Post-Cold War 🔗 NATO

Operation Gladio is the codename for clandestine "stay-behind" operations of armed resistance that were organized by the Western Union (WU), and subsequently by NATO and the CIA, in collaboration with several European intelligence agencies. The operation was designed for a potential Warsaw Pact invasion and conquest of Europe. Although Gladio specifically refers to the Italian branch of the NATO stay-behind organizations, "Operation Gladio" is used as an informal name for all of them. Stay-behind operations were prepared in many NATO member countries, and some neutral countries.

During the Cold War, some anti-communist armed groups engaged in the harassment of left-wing parties, torture, terrorist attacks, and massacres in countries such as Italy. The role of the CIA and other intelligence organisations in Gladio—the extent of its activities during the Cold War era and any responsibility for terrorist attacks perpetrated in Italy during the "Years of Lead" (late 1960s–early 1980s)—is the subject of debate.

In 1990, the European Parliament adopted a resolution alleging that military secret services in certain member states were involved in serious terrorism and crime, whether or not their superiors were aware. The resolution also urged investigations by the judiciaries of the countries in which those armies operated, so that their modus operandi and actual extension would be revealed. To date, only Italy, Switzerland and Belgium have had parliamentary inquiries into the matter.

The three inquiries reached differing conclusions as regarded different countries. Guido Salvini, a judge who worked in the Italian Massacres Commission, concluded that some right-wing terrorist organizations of the Years of Lead (La Fenice, National Vanguard and Ordine Nuovo) were the trench troops of a secret army, remotely controlled by exponents of the Italian state apparatus and linked to the CIA. Salvini said that the CIA encouraged them to commit atrocities. The Swiss inquiry found that British intelligence secretly cooperated with their army in an operation named P-26 and provided training in combat, communications, and sabotage. It also discovered that P-26 not only would organize resistance in case of a Soviet invasion, but would also become active should the left succeed in achieving a parliamentary majority. The Belgian inquiry could find no conclusive information on their army. No links between them and terrorist attacks were found, and the inquiry noted that the Belgian secret services refused to provide the identity of agents, which could have eliminated all doubts. A 2000 Italian parliamentary report from the left wing coalition Gruppo Democratici di Sinistra l'Ulivo reported that terrorist massacres and bombings had been organised or promoted or supported by men inside Italian state institutions who were linked to American intelligence. The report also said the United States was guilty of promoting the strategy of tension. Operation Gladio is also suspected to have been activated to counter existing left-wing parliamentary majorities in Europe.

The US State Department published a communiqué in January 2006 that stated claims the United States ordered, supported, or authorized terrorism by stay-behind units, and US-sponsored "false flag" operations are rehashed former Soviet disinformation based on documents that the Soviets forged.

The word gladio is the Italian form of gladius, a type of Roman shortsword.

🔗 Biography 🔗 Norway

Erik Naggum (June 13, 1965 – June 17, 2009) was a Norwegian computer programmer recognized for his work in the fields of SGML, Emacs and Lisp. Since the early 1990s he was also a provocative participant on various Usenet discussion groups.

Naggum made significant contributions to RFC 1123, which defines and discusses the requirements for Internet host software, and RFC 2049, which defines electronic information transfer of various binary formats through e-mail.

In a 1999 newspaper article in Dagbladet, he was interviewed about his aggressive, confrontational participation in Usenet discussion groups. Erik later stated his motto to be: "Some people are little more than herd animals, flocking together whenever the world becomes uncomfortable … I am not one of those people. If I had a motto, it would probably be Herd thither, me hither."

His death on June 17, 2009 (aged 44), was caused by a massive bleeding ulcer, related to ulcerative colitis, which he was diagnosed with about 15 years before his death.

🔗 Industrial design

The Xerox 914 was the first successful commercial plain paper copier which in 1959 revolutionized the document-copying industry. The culmination of inventor Chester Carlson's work on the xerographic process, the 914 was fast and economical. The copier was introduced to the public on September 16, 1959, in a demonstration at the Sherry-Netherland Hotel in New York, shown on live television.