To stay up to date you can also follow on Mastodon.

🔗 Classical Greece and Rome 🔗 Greece 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Sociology 🔗 Sports 🔗 Greece/Byzantine world

The Nika riots (Greek: Στάσις τοῦ Νίκα, romanized: Stásis toû Níka), Nika revolt or Nika sedition took place against Byzantine emperor Justinian I in Constantinople over the course of a week in 532 C.E. They are often regarded as the most violent riots in the city's history, with nearly half of Constantinople being burned or destroyed and tens of thousands of people killed.

🔗 Biography 🔗 Biography/arts and entertainment 🔗 Japan 🔗 Photography 🔗 Japan/History 🔗 Japan/Science and technology 🔗 Photography/History of photography 🔗 Japan/Biography

Ichiki Shirō (市来 四郎, January 29, 1828 – February 12, 1903) was a pioneering Japanese photographer.

Ichiki was born in Satsuma Province (now Kagoshima Prefecture) in Kyūshū on 24 December 1828. He excelled in the study of topics related to gunpowder production in the Takashima-ryū school of gunnery. This talent was recognized by Shimazu Nariakira, the daimyō of Satsuma, who selected Ichiki to be one of his personal retainers. In 1848, Shimazu obtained the first daguerreotype camera ever imported into Japan. Ever fascinated by Western technology, he ordered his retainers (including Ichiki) to study it and produce working photographs. Due to the limitations of the lens used and the lack of formal training, it took many years for a quality photograph to be created, but on 17 September 1857, Ichiki created a portrait of Shimazu in formal attire. All this was recorded in detail in Ichiki's memoirs, which were compiled in 1884.

This photograph became an object of worship in Terukuni jinja after Shimazu's death, but it later went missing. Lost for a century, the daguerreotype was discovered in a warehouse in 1975 and was later determined to be the oldest daguerreotype in existence that was created by a Japanese photographer. For this reason, it was designated an Important Cultural Property by the government of Japan in 1999, the first photograph so designated.

🔗 Civil engineering 🔗 Netherlands

The Maeslantkering ("Maeslant barrier" in Dutch) is a storm surge barrier on the Nieuwe Waterweg, in South Holland, Netherlands. It was constructed from 1991 to 1997. As part of the Delta Works the barrier responds to water level predictions calculated by a centralized computer system called BOS. It automatically closes when Rotterdam (especially the Port of Rotterdam) is threatened by floods.

Maeslantkering has two 210-metre long barrier gates, with two 237-metre long steel trusses holding each. When closed, the barrier will protect the entire width (360 metres) of the Nieuwe Waterweg, the main waterway of Port of Rotterdam. It is one of the largest moving structures on Earth, rivalling the Green Bank Telescope in the United States and the Bagger 288 excavator in Germany.

🔗 Computing 🔗 Computer science

Note G was a computer algorithm written by Ada Lovelace, and was designed to calculate Bernoulli numbers using the hypothetical analytical engine. Note G is generally agreed to be the first algorithm specifically for a computer, and Lovelace is considered as the first computer programmer as a result. The algorithm was the last note in a series labelled A to G, which she employed as visual aids to accompany her English translation of Luigi Menabrea's 1842 French transcription of Charles Babbage's lecture on the analytical engine at the University of Turin, "Notions sur la machine analytique de Charles Babbage" ("Elements of Charles Babbage’s Analytical Machine"). Lovelace's Note G was never tested, as the engine was never built. Her notes, along with her translation, were published in 1843.

In the modern era, thanks to more readily available computing equipment and programming resources, Lovelace's algorithm has since been tested, after being "translated" into modern programming languages. These tests have independently concluded that there was a bug in the script, due to a minor typographical error, rendering the algorithm in its original state unusable.

🔗 Philosophy 🔗 Science Fiction 🔗 Literature 🔗 Philosophy/Epistemology

Sturgeon's revelation (as expounded by Theodore Sturgeon), referred to as Sturgeon's law, is an adage cited as "ninety percent of everything is crap." The sentence derives from quotations by Sturgeon, an American science fiction author and critic; although Sturgeon coined another adage he termed "Sturgeon's law", the "ninety percent crap" remark became Sturgeon's law.

The phrase was derived from Sturgeon's observation while science fiction was often derided for its low quality by critics, the majority of examples of works in other fields could equally be seen to be of low quality, and science fiction was thus no different in that regard from other art forms.

🔗 Apps

Send Me To Heaven (officially stylized as S.M.T.H.) is an Android application developed by Carrot Pop which measures the vertical distance that a mobile phone is thrown. Players compete against each other by seeking to throw their phones higher than others, often at the risk of damaging their phones. The app was immediately banned from the App Store but remains available from Google Play, where it maintains a cult following.

🔗 Aviation 🔗 Aviation/gliding

Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity. Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is mainly of use to birds and operators of radio-controlled gliders, but glider pilots are sometimes able to soar dynamically in meteorological wind shears at higher altitudes.

Dynamic soaring is sometimes confused with slope soaring which is a technique for achieving elevation.

🔗 Linguistics

Oi is an interjection used in various varieties of the English language, particularly Australian English, British English, Indian English, Irish English, New Zealand English, and South African English, as well as non-English languages such as Chinese, Tagalog, Tamil, Hindi/Urdu, Japanese, and Portuguese to get the attention of another person or to express surprise or disapproval. It is sometimes used in Canadian English and very rarely in American English. The word is also common in the Indian subcontinent, where it has varied pronunciations of "O-ee" and "O-ye".

"Oi" has been particularly associated with working class and Cockney speech. It is effectively a local pronunciation of "hoy" (see H-dropping), an older expression. A study of the Cockney dialect in the 1950s found that whether it was being used to call attention or as a challenge depended on its tone and abruptness. The study's author noted that the expression is "jaunty and self-assertive" as well as "intensely cockney".

A poll of non-English speakers by the British Council in 2004 found that "oi" was considered the 61st most beautiful word in the English language. A spokesman commented that "Oi is not a word that I would've thought turned up in English manuals all that often." "Oi" was added to the list of acceptable words in US Scrabble in 2006.

🔗 Mathematics

In mathematics, in the area of harmonic analysis, the fractional Fourier transform (FRFT) is a family of linear transformations generalizing the Fourier transform. It can be thought of as the Fourier transform to the n-th power, where n need not be an integer — thus, it can transform a function to any intermediate domain between time and frequency. Its applications range from filter design and signal analysis to phase retrieval and pattern recognition.

The FRFT can be used to define fractional convolution, correlation, and other operations, and can also be further generalized into the linear canonical transformation (LCT). An early definition of the FRFT was introduced by Condon, by solving for the Green's function for phase-space rotations, and also by Namias, generalizing work of Wiener on Hermite polynomials.

However, it was not widely recognized in signal processing until it was independently reintroduced around 1993 by several groups. Since then, there has been a surge of interest in extending Shannon's sampling theorem for signals which are band-limited in the Fractional Fourier domain.

A completely different meaning for "fractional Fourier transform" was introduced by Bailey and Swartztrauber as essentially another name for a z-transform, and in particular for the case that corresponds to a discrete Fourier transform shifted by a fractional amount in frequency space (multiplying the input by a linear chirp) and evaluating at a fractional set of frequency points (e.g. considering only a small portion of the spectrum). (Such transforms can be evaluated efficiently by Bluestein's FFT algorithm.) This terminology has fallen out of use in most of the technical literature, however, in preference to the FRFT. The remainder of this article describes the FRFT.