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🔗 Mathematics

Graham's number is an immense number that arises as an upper bound on the answer of a problem in the mathematical field of Ramsey theory. It is named after mathematician Ronald Graham, who used the number in conversations with popular science writer Martin Gardner as a simplified explanation of the upper bounds of the problem he was working on. In 1977, Gardner described the number in Scientific American, introducing it to the general public. At the time of its introduction, it was the largest specific positive integer ever to have been used in a published mathematical proof. The number was published in the 1980 Guinness Book of World Records, adding to its popular interest. Other specific integers (such as TREE(3)) known to be far larger than Graham's number have since appeared in many serious mathematical proofs, for example in connection with Harvey Friedman's various finite forms of Kruskal's theorem. Additionally, smaller upper bounds on the Ramsey theory problem from which Graham's number derived have since been proven to be valid.

Graham's number is much larger than many other large numbers such as Skewes' number and Moser's number, both of which are in turn much larger than a googolplex. As with these, it is so large that the observable universe is far too small to contain an ordinary digital representation of Graham's number, assuming that each digit occupies one Planck volume, possibly the smallest measurable space. But even the number of digits in this digital representation of Graham's number would itself be a number so large that its digital representation cannot be represented in the observable universe. Nor even can the number of digits of that number—and so forth, for a number of times far exceeding the total number of Planck volumes in the observable universe. Thus Graham's number cannot be expressed even by power towers of the form ${\displaystyle a^{b^{c^{\cdot ^{\cdot ^{\cdot }}}}}}$.

However, Graham's number can be explicitly given by computable recursive formulas using Knuth's up-arrow notation or equivalent, as was done by Graham. As there is a recursive formula to define it, it is much smaller than typical busy beaver numbers. Though too large to be computed in full, the sequence of digits of Graham's number can be computed explicitly through simple algorithms. The last 12 digits are ...262464195387. With Knuth's up-arrow notation, Graham's number is ${\displaystyle g_{64}}$, where

🔗 Languages 🔗 Ottoman Empire 🔗 Western Asia

The language of the court and government of the Ottoman Empire was Ottoman Turkish, but many other languages were in contemporary use in parts of the empire. Although the minorities of the Ottoman Empire were free to use their language amongst themselves, if they needed to communicate with the government they had to use Ottoman Turkish.

The Ottomans had three influential languages: Turkish, spoken by the majority of the people in Anatolia and by the majority of Muslims of the Balkans except in Albania, Bosnia, and various Aegean Sea islands; Persian, initially used by the educated in northern portions of the Ottoman Empire before being displaced by Ottoman Turkish; and Arabic, used in southern portions of the Ottoman Empire; Arabic was spoken mainly in Arabia, North Africa, Mesopotamia and the Levant. Throughout the vast Ottoman bureaucracy Ottoman Turkish language was the official language, a version of Turkish, albeit with a vast mixture of both Arabic and Persian grammar and vocabulary.

Virtually all intellectual and literate pursuits were taken in Turkish language. Some ordinary people had to hire special "request-writers" (arzuhâlcis) to be able to communicate with the government. The ethnic groups continued to speak within their families and neighborhoods (mahalles) with their own languages (e.g., Jews, Greeks, Armenians, etc.) In villages where two or more populations lived together, the inhabitants would often speak each other's language. In cosmopolitan cities, people often spoke their family languages, many non-ethnic Turks spoke Turkish as a second language. Educated Ottoman Turks spoke Arabic and Persian, as these were the main foreign languages in the pre-Tanzimat era, with the former being used for science and the latter for literary affairs.

In the last two centuries, French and English emerged as popular languages, especially among the Christian Levantine communities. The elite learned French at school, and used European products as a fashion statement. The use of Ottoman Turkish for science and literature grew steadily under the Ottomans, while Persian declined in those functions. Ottoman Turkish, during the period, gained many loanwords from Arabic and Persian. Up to 88% of the vocabulary of a particular work would be borrowed from those two languages.

Linguistic groups were varied and overlapping. In the Balkan Peninsula, Slavic, Greek and Albanian speakers were the majority, but there were substantial minorities of Turks and Romance-speaking Vlachs. In most of Anatolia, Turkish was the majority language, but Greek, Armenian and, in the east and southeast, Kurdish were also spoken. In Syria, Iraq, Arabia, Egypt and north Africa, most of the population spoke varieties of Arabic with, above them, a Turkish-speaking elite. However, in no province of the Empire was there a unique language.

🔗 Software 🔗 Software/Computing

In the context of Unix-like systems, the term rc stands for the phrase "run commands". It is used for any file that contains startup information for a command. It is believed to have originated sometime in 1965 at a runcom facility from the MIT Compatible Time-Sharing System (CTSS).

From Brian Kernighan and Dennis Ritchie:

There was a facility that would execute a bunch of commands stored in a file; it was called runcom for "run commands", and the file began to be called "a runcom". rc in Unix is a fossil from that usage.

Tom Van Vleck, a Multics engineer, has also reminisced about the extension rc: "The idea of having the command processing shell be an ordinary slave program came from the Multics design, and a predecessor program on CTSS by Louis Pouzin called RUNCOM, the source of the '.rc' suffix on some Unix configuration files."

This is also the origin of the name of the Plan 9 from Bell Labs shell by Tom Duff, the rc shell. It is called "rc" because the main job of a shell is to "run commands".

While not historically precise, rc may also be expanded as "run control", because an rc file controls how a program runs. For instance, the editor Vim looks for and reads the contents of the .vimrc file to determine its initial configuration. In The Art of Unix Programming, Eric S. Raymond consistently refers to rc files as "run-control" files.

🔗 Television 🔗 Korea 🔗 Fashion 🔗 Korea/North Korea

Let's trim our hair in accordance with the socialist lifestyle (alternatively translated as Let us trim our hair in accordance with Socialist lifestyle) is a television program that was part of a North Korean government propaganda campaign promulgating grooming and dress standards in 2004–2005.

It was broadcast on state-run Korean Central Television in the capital of Pyongyang and clips from the program were later rebroadcast on the British channel BBC One. The program claimed that hair length can affect human intelligence, in part because of the deprivation to the rest of the body of nutrients required for hair to grow. However, although some researchers have proposed that brain and hair are in competition from an evolutionary standpoint, cutting hair has no influence on its rate of growth. It was part of a longstanding North Korean government restriction campaign against haircuts and fashions deemed at odds with "Socialist values".

🔗 Volcanoes 🔗 Islands 🔗 Sicily 🔗 Seamounts

Graham Island (also Graham Bank or Graham Shoal; Italian: Isola Ferdinandea) is a submerged volcanic island in the Mediterranean Sea. It was discovered when it last appeared on 1 August 1831 by Humphrey Fleming Senhouse, the captain of the first rate Royal Navy ship of the line St Vincent and named after Sir James Graham, the First Lord of the Admiralty. It was claimed by the United Kingdom. It forms part of the underwater volcano Empedocles, 30 km (19 mi) south of Sicily, and which is one of a number of submarine volcanoes known as the Campi Flegrei del Mar di Sicilia. Seamount eruptions have raised it above sea level several times before erosion submerged it again.

When it last rose above sea level after erupting in 1831, a four-way dispute over its sovereignty began, which was still unresolved when it disappeared beneath the waves again in early 1832. During its brief life, French geologist Constant Prévost was on hand, accompanied by an artist, to witness it in July 1831; he named it Île Julia, for its July appearance, and reported in the Bulletin de la Société Géologique de France. Some observers at the time wondered if a chain of mountains would spring up, linking Sicily to Tunisia and thus upsetting the geopolitics of the region. It showed signs of volcanic activity in 2000 and 2002, forecasting a possible appearance; however, as of 2016 it remains 6 m (20 ft) under sea level.

🔗 Human rights 🔗 Computing 🔗 Finance & Investment 🔗 Law 🔗 Computing/Software 🔗 Software 🔗 Software/Computing 🔗 United Kingdom

The British Post Office scandal is a widespread and long-lasting series of individual miscarriages of justice which, between 1999 and 2015, involved over 700 subpostmasters being wrongly convicted of theft, false accounting and fraud when shortfalls at their branches were in fact due to errors of the Post Office's Horizon accounting software. In 2019, the High Court ruled that the Horizon system was faulty and in 2020 the government established a public inquiry. Courts began to quash convictions from 2010. As of January 2024, some victims are still fighting to have their convictions overturned and receive compensation, the public inquiry is ongoing, and the Metropolitan Police is investigating the Post Office for potential fraud offences.

The Horizon accounting system was developed by ICL Pathway, owned by the Japanese company Fujitsu. In 1999, the Post Office started to roll out the new software to its branch and sub-offices, the latter managed by subpostmasters on a self-employed basis under contracts with the Post Office. Almost immediately, some subpostmasters noticed the new system reporting false shortfalls, sometimes for thousands of pounds. The Post Office insisted that the system was robust and, when shortfalls occurred, prosecuted the subpostmasters or forced them to make up the amount. The impact of court cases, criminal convictions, imprisonment, loss of livelihood and homes, debt and bankruptcy took a heavy toll on victims and their families, leading to stress, illness, divorce and, in at least four cases, suicide. In May 2009, Computer Weekly broke the story about problems with Horizon software and in September 2009 subpostmaster Alan Bates set up the Justice for Subpostmasters Alliance (JFSA). In 2012, as a result of pressure from campaigners and Members of Parliament, the Post Office appointed forensic accountants Second Sight to conduct an investigation into Horizon. The investigators concluded that Horizon contained faults that could result in accounting discrepancies, but the Post Office insisted that there were no system-wide problems with the software.

In 2019 a group of 555 subpostmasters led by Bates won a group action brought in court against the Post Office, with the judge ruling that Horizon contained bugs, errors and defects. The Post Office agreed to settle out of court for £58 million. The subpostmasters' legal costs amounted to £47 million of, leaving them with only about £20,000 each. The government later agreed to supplement the settlement, as they were excluded from the compensation scheme set up by the Post Office for other victims of the scandal. The first convictions to be quashed were those of six subpostmasters who had been convicted in magistrates' courts and whose appeals were heard at Southwark Crown Court in December 2020. In allowing the appeal by 39 subpostmasters in April 2021, the Court of Appeal judges ruled that in cases that relied on Horizon data a fair trial was not possible. Further appeal cases followed.

In September 2020, the government established the Post Office Horizon IT Inquiry, chaired by retired judge Sir Wyn Williams, to look into the implementation and failings of the Horizon system that led to the prosecution of subpostmasters and termination of their contracts. Evidence was due to be heard from subpostmasters, the Post Office, UK Government Investment, the Department for Business and Trade, and others.

A four-part television drama, Mr Bates vs the Post Office, was broadcast on ITV in January 2024, after which the scandal became a major news story and political issue.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 Film/Silent films 🔗 Film/Documentary films 🔗 United States/Film - American cinema

A Trip Down Market Street is a 13-minute actuality film recorded by placing a movie camera on the front of a cable car as it traveled down San Francisco’s Market Street. The film shows many details of daily life in a major early 20th century American city, including the transportation, fashions and architecture of the era. The film begins at 8th Street and continues eastward to the cable car turntable, at The Embarcadero, in front of the Ferry Building. Landmarks passed in the latter part of the first half include the Call Building (then San Francisco's tallest) and the Palace Hotel (both on the right; Lotta's Fountain is on the left between the two but is in the shade). The film was produced by the four Miles brothers: Harry, Herbert, Earle and Joe. It is notable for capturing San Francisco four days before the 1906 San Francisco earthquake, which started on the morning of Wednesday, April 18, 1906.

The Miles brothers had been producing films in New York including films shot in San Francisco. In September 1905 they shot the fight between Oscar "Battling" Nelson and Jimmy Britt in Colma, California, just south of San Francisco city limits. The Miles brothers established a studio at 1139 Market Street in San Francisco in early 1906. They shot a railroad descent down Mount Tamalpais as well as the Market Street film. On April 17, Harry and Joe Miles boarded a train for New York, taking the two films with them, but they heard about the earthquake and sent the films to New York while they boarded another train headed back to San Francisco. The Turk Street house of Earle Miles survived the earthquake and subsequent catastrophic fire but the studio did not. The Miles brothers based their business out of Earle's home, and shot more film of post-earthquake scenes; some of this footage, including that of a second trip down a now devastated Market Street, reemerged in 2016. It is likely that the Market Street film survives today because it was sent away before the fire.

Several 35mm prints exist with slight changes in footage. Copies are held at the Library of Congress and the Prelinger Archives. A digital version is viewable online at Internet Archive, YouTube and Wikimedia Commons. In 2010, the film was selected for preservation in the National Film Registry by the Library of Congress.

🔗 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.

🔗 Medicine 🔗 Statistics 🔗 Microbiology 🔗 Game theory

Herd immunity (also called herd effect, community immunity, population immunity, or social immunity) is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby providing a measure of protection for individuals who are not immune. In a population in which a large proportion of individuals possess immunity, such people being unlikely to contribute to disease transmission, chains of infection are more likely to be disrupted, which either stops or slows the spread of disease. The greater the proportion of immune individuals in a community, the smaller the probability that non-immune individuals will come into contact with an infectious individual, helping to shield non-immune individuals from infection.

Individuals can become immune by recovering from an earlier infection or through vaccination. Some individuals cannot become immune due to medical reasons, such as an immunodeficiency or immunosuppression, and in this group herd immunity is a crucial method of protection. Once a certain threshold has been reached, herd immunity gradually eliminates a disease from a population. This elimination, if achieved worldwide, may result in the permanent reduction in the number of infections to zero, called eradication. Herd immunity created via vaccination contributed to the eventual eradication of smallpox in 1977 and has contributed to the reduction of the frequencies of other diseases. Herd immunity does not apply to all diseases, just those that are contagious, meaning that they can be transmitted from one individual to another. Tetanus, for example, is infectious but not contagious, so herd immunity does not apply.

The term "herd immunity" was first used in 1923. It was recognized as a naturally occurring phenomenon in the 1930s when it was observed that after a significant number of children had become immune to measles, the number of new infections temporarily decreased, including among susceptible children. Mass vaccination to induce herd immunity has since become common and proved successful in preventing the spread of many infectious diseases. Opposition to vaccination has posed a challenge to herd immunity, allowing preventable diseases to persist in or return to communities that have inadequate vaccination rates.

🔗 Biography 🔗 Syria

Bassel Khartabil (Arabic: باسل خرطبيل‎), also known as Bassel Safadi (Arabic: باسل صفدي‎), (22 May 1981, Damascus – 3 October 2015) was a Palestinian Syrian open-source software developer. On 15 March 2012, the one-year anniversary of the Syrian uprising, he was detained by the Syrian government at Adra Prison in Damascus. Between then and 3 October 2015, he had been transferred to an unknown location, probably to be judged by a military court. On 7 October 2015, Human Rights Watch and 30 other human rights organizations issued a letter demanding that Khartabil's whereabouts be disclosed. On 11 November 2015, rumors surfaced that Khartabil had been secretly sentenced to death. In August 2017, his wife made public that Khartabil had been executed by the Syrian regime shortly after his disappearance in 2015.

Khartabil was born in Damascus and raised in Syria, where he specialized in open source software development. He was chief technology officer (CTO) and co-founder of collaborative research company Aiki Lab and was CTO of Al-Aous, a publishing and research institution dedicated to archaeological sciences and arts in Syria. He has served as project lead and public affiliate for Creative Commons Syria, and has contributed to Mozilla Firefox, Wikipedia, Openclipart, Fabricatorz, and Sharism. He "is credited with opening up the Internet in Syria and vastly extending online access and knowledge to the Syrian people."

His last work included an open, 3D virtual reconstruction of the ancient city of Palmyra in Syria, real time visualization, and development with Fabricatorz for the web programming framework Aiki Framework. This was later created and displayed in his honor.

On February 7, 2018, the Bassel Khartabil Free Culture Fellowship was announced in Bassel's memory. The fellowship awards $50,000, including additional support, to outstanding individuals developing open culture in their communities. The fellowship was created by Creative Commons, Fabricatorz Foundation, Jimmy Wales Foundation, Mozilla, #NEWPALMYRA, and Wikimedia.