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🔗 United States 🔗 Computing 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Iran 🔗 Computing/Software 🔗 Computing/Computer Security 🔗 Military history/Middle Eastern military history

Stuxnet is a malicious computer worm, first uncovered in 2010, thought to have been in development since at least 2005. Stuxnet targets supervisory control and data acquisition (SCADA) systems and is believed to be responsible for causing substantial damage to the nuclear program of Iran. Although neither country has openly admitted responsibility, the worm is widely understood to be a cyberweapon built jointly by the United States and Israel.

Stuxnet specifically targets programmable logic controllers (PLCs), which allow the automation of electromechanical processes such as those used to control machinery and industrial processes including gas centrifuges for separating nuclear material. Exploiting four zero-day flaws, Stuxnet functions by targeting machines using the Microsoft Windows operating system and networks, then seeking out Siemens Step7 software. Stuxnet reportedly compromised Iranian PLCs, collecting information on industrial systems and causing the fast-spinning centrifuges to tear themselves apart. Stuxnet's design and architecture are not domain-specific and it could be tailored as a platform for attacking modern supervisory control and data acquisition (SCADA) and PLC systems (e.g., in factory assembly lines or power plants), most of which are in Europe, Japan, and the US. Stuxnet reportedly ruined almost one-fifth of Iran's nuclear centrifuges. Targeting industrial control systems, the worm infected over 200,000 computers and caused 1,000 machines to physically degrade.

Stuxnet has three modules: a worm that executes all routines related to the main payload of the attack; a link file that automatically executes the propagated copies of the worm; and a rootkit component responsible for hiding all malicious files and processes, to prevent detection of Stuxnet. It is typically introduced to the target environment via an infected USB flash drive, thus crossing any air gap. The worm then propagates across the network, scanning for Siemens Step7 software on computers controlling a PLC. In the absence of either criterion, Stuxnet becomes dormant inside the computer. If both the conditions are fulfilled, Stuxnet introduces the infected rootkit onto the PLC and Step7 software, modifying the code and giving unexpected commands to the PLC while returning a loop of normal operation system values back to the users.

In 2015, Kaspersky Lab noted that the Equation Group had used two of the same zero-day attacks prior to their use in Stuxnet and commented that "the similar type of usage of both exploits together in different computer worms, at around the same time, indicates that the Equation Group and the Stuxnet developers are either the same or working closely together".

🔗 Mathematics 🔗 France

Nicolas Bourbaki (French pronunciation: ​[nikɔla buʁbaki]) is the collective pseudonym of a group of mathematicians, predominantly French alumni of the École normale supérieure (ENS). Founded in 1934–1935, the Bourbaki group originally intended to prepare a new textbook in analysis. Over time the project became much more ambitious, growing into a large series of textbooks published under the Bourbaki name, meant to treat modern pure mathematics. The series is known collectively as the Éléments de mathématique (Elements of Mathematics), the group's central work. Topics treated in the series include set theory, abstract algebra, topology, analysis, Lie groups and Lie algebras.

Bourbaki was founded in response to the effects of the First World War which caused the death of a generation of French mathematicians; as a result, young university instructors were forced to use dated texts. While teaching at the University of Strasbourg, Henri Cartan complained to his colleague André Weil of the inadequacy of available course material, which prompted Weil to propose a meeting with others in Paris to collectively write a modern analysis textbook. The group's core founders were Cartan, Claude Chevalley, Jean Delsarte, Jean Dieudonné and Weil; others participated briefly during the group's early years, and membership has changed gradually over time. Although former members openly discuss their past involvement with the group, Bourbaki has a custom of keeping its current membership secret.

The group's namesake derives from the 19th century French general Charles-Denis Bourbaki, who had a career of successful military campaigns before suffering a dramatic loss in the Franco-Prussian War. The name was therefore familiar to early 20th century French students. Weil remembered an ENS student prank in which an upperclassman posed as a professor and presented a "theorem of Bourbaki"; the name was later adopted.

The Bourbaki group holds regular private conferences for the purpose of drafting and expanding the Éléments. Topics are assigned to subcommittees, drafts are debated, and unanimous agreement is required before a text is deemed fit for publication. Although slow and labor-intensive, the process results in a work which meets the group's standards for rigour and generality. The group is also associated with the Séminaire Bourbaki, a regular series of lectures presented by members and non-members of the group, also published and disseminated as written documents. Bourbaki maintains an office at the ENS.

Nicolas Bourbaki was influential in 20th century mathematics, particularly during the middle of the century when volumes of the Éléments appeared frequently. The group is noted among mathematicians for its rigorous presentation and for introducing the notion of a mathematical structure, an idea related to the broader, interdisciplinary concept of structuralism. Bourbaki's work informed the New Math, a trend in elementary math education during the 1960s. Although the group remains active, its influence is considered to have declined due to infrequent publication of new volumes of the Éléments. However the collective's most recent publication appeared in 2016, treating algebraic topology.

🔗 United Kingdom 🔗 Classical music 🔗 Classical music/Compositions

Edward Elgar composed his Variations on an Original Theme, Op. 36, popularly known as the Enigma Variations, between October 1898 and February 1899. It is an orchestral work comprising fourteen variations on an original theme.

Elgar dedicated the work "to my friends pictured within", each variation being a musical sketch of one of his circle of close acquaintances (see musical cryptogram). Those portrayed include Elgar's wife Alice, his friend and publisher Augustus J. Jaeger and Elgar himself. In a programme note for a performance in 1911 Elgar wrote:

This work, commenced in a spirit of humour & continued in deep seriousness, contains sketches of the composer's friends. It may be understood that these personages comment or reflect on the original theme & each one attempts a solution of the Enigma, for so the theme is called. The sketches are not 'portraits' but each variation contains a distinct idea founded on some particular personality or perhaps on some incident known only to two people. This is the basis of the composition, but the work may be listened to as a 'piece of music' apart from any extraneous consideration.

In naming his theme "Enigma", Elgar posed a challenge which has generated much speculation but has never been conclusively answered. The Enigma is widely believed to involve a hidden melody.

After its 1899 London premiere the Variations achieved immediate popularity and established Elgar's international reputation.

🔗 Computing 🔗 Computer science

In computer science, the five-minute rule is a rule of thumb for deciding whether a data item should be kept in memory, or stored on disk and read back into memory when required. It was first formulated by Jim Gray and Gianfranco Putzolu in 1985, and then subsequently revised in 1997 and 2007 to reflect changes in the relative cost and performance of memory and persistent storage.

The rule is as follows:

The 5-minute random rule: cache randomly accessed disk pages that are re-used every 5 minutes or less.

Gray also issued a counterpart one-minute rule for sequential access:

The 1-minute rule: cache sequentially accessed disk pages that are re-used every 1 minute or less.

Although the 5-minute rule was invented in the realm of databases, it has also been applied elsewhere, for example, in Network File System cache capacity planning.

The original 5-minute rule was derived from the following cost-benefit computation:

BreakEvenIntervalinSeconds = (PagesPerMBofRAM / AccessesPerSecondPerDisk) × (PricePerDiskDrive / PricePerMBofRAM)

Applying it to 2007 data yields approximately a 90-minutes interval for magnetic-disk-to-DRAM caching, 15 minutes for SSD-to-DRAM caching and 2​¹⁄₄ hours for disk-to-SSD caching. The disk-to-DRAM interval was thus a bit short of what Gray and Putzolu anticipated in 1987 as the "five-hour rule" was going to be in 2007 for RAM and disks.

According to calculations by NetApp engineer David Dale as reported in The Register, the figures for disc-to-DRAM caching in 2008 were as follows: "The 50KB page break-even was five minutes, the 4KB one was one hour and the 1KB one was five hours. There needed to be a 50-fold increase in page size to cache for break-even at five minutes." Regarding disk-to-SSD caching in 2010, the same source reported that "A 250KB page break even with SLC was five minutes, but five hours with a 4KB page size. It was five minutes with a 625KB page size with MLC flash and 13 hours with a 4KB MLC page size."

In 2000, Gray and Shenoy applied a similar calculation for web page caching and concluded that a browser should "cache web pages if there is any chance they will be re-referenced within their lifetime."

🔗 Telecommunications

Digital mobile radio (DMR) is a limited open digital mobile radio standard defined in the European Telecommunications Standards Institute (ETSI) Standard TS 102 361 parts 1–4 and used in commercial products around the world. DMR, along with P25 phase II and NXDN are the main competitor technologies in achieving 6.25 kHz equivalent bandwidth using the proprietary AMBE+2 vocoder. DMR and P25 II both use two-slot TDMA in a 12.5 kHz channel, while NXDN uses discrete 6.25 kHz channels using frequency division and TETRA uses a four-slot TDMA in a 25 kHz channel.

DMR was designed with three tiers. DMR tiers I and II (conventional) were first published in 2005, and DMR III (Trunked version) was published in 2012, with manufacturers producing products within a few years of each publication.

The primary goal of the standard is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers are not locked into a proprietary solution. In practice, given the current limited scope of the DMR standard, many vendors have introduced proprietary features that make their product offerings non-interoperable with other brands.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Linguistics 🔗 Philosophy/Philosophy of language 🔗 Linguistics/Philosophy of language

Colorless green ideas sleep furiously is a sentence composed by Noam Chomsky in his 1957 book Syntactic Structures as an example of a sentence that is grammatically correct, but semantically nonsensical. The sentence was originally used in his 1955 thesis The Logical Structure of Linguistic Theory and in his 1956 paper "Three Models for the Description of Language". Although the sentence is grammatically correct, no obvious understandable meaning can be derived from it, and thus it demonstrates the distinction between syntax and semantics. As an example of a category mistake, it was used to show the inadequacy of certain probabilistic models of grammar, and the need for more structured models.

🔗 Mass surveillance 🔗 Law

Wikimedia Foundation, et al. v. National Security Agency, et al. is a lawsuit filed by the American Civil Liberties Union (ACLU) on behalf of the Wikimedia Foundation and several other organizations against the National Security Agency (NSA), the United States Department of Justice (DOJ), and other named individuals, alleging mass surveillance of Wikipedia users carried out by the NSA. The suit claims the surveillance system, which NSA calls "Upstream", breaches the First Amendment to the United States Constitution, which protects freedom of speech, and the Fourth Amendment to the United States Constitution, which prohibits unreasonable searches and seizures.

The suit was filed in the United States District Court for the District of Maryland as the NSA is based in Fort Meade, Maryland. The suit was dismissed in October 2015 by Judge T. S. Ellis III; this decision was appealed four months later to the Fourth Circuit Court of Appeals by the Wikimedia Foundation. The Court of Appeals found that the dismissal was valid for all of the plaintiffs except the Foundation, whose allegations the court found "plausible" enough to have legal standing for the case to be remanded to the lower court.

The original plaintiffs besides the Wikimedia Foundation were the National Association of Criminal Defense Lawyers, Human Rights Watch, Amnesty International USA, the PEN American Center, the Global Fund for Women, The Nation magazine, the Rutherford Institute, and the Washington Office on Latin America.

🔗 Russia 🔗 Crime 🔗 Death 🔗 Russia/politics and law of Russia

The assassination of Boris Nemtsov, a Russian politician opposed to the government of Vladimir Putin, occurred in central Moscow on Bolshoy Moskvoretsky Bridge at 23:31 local time on 27 February 2015. An unknown assailant fired seven or eight shots from a Makarov pistol; four of them hit Boris Nemtsov in the head, heart, liver and stomach, killing him almost instantly. He died hours after appealing to the public to support a march against Russia's war in Ukraine. Nemtsov's Ukrainian partner Anna Duritskaya survived the attack as its sole eyewitness.

The assassination was met with worldwide condemnation and concern for the situation of the Russian opposition. Russian authorities also condemned the murder and vowed to conduct a thorough investigation.

On 8 March 2015, Russian authorities charged Anzor Gubashev and Zaur Dadaev, both originating from the Northern Caucasus, with involvement in the crime. According to Russian authorities, Dadaev confessed to involvement in the murder. However, he later retracted his statement, as extracted by torture. Three more suspects were arrested around the same time and, according to Russian media, another suspect blew himself up in Grozny when Russian police forces surrounded his apartment block.

🔗 United States 🔗 Organizations 🔗 Birds 🔗 Indigenous peoples of North America 🔗 United States/Colorado

The National Eagle Repository is operated and managed under the Office of Law Enforcement of the United States Fish and Wildlife Service located at the Rocky Mountain Arsenal National Wildlife Refuge outside of Denver, Colorado. It serves as a central location for the receipt, storage, and distribution of bald and golden eagles that have been found dead. Eagles and eagle parts are available only to Native Americans enrolled in federally recognized tribes for use in religious and cultural ceremonies.

🔗 Biography 🔗 Comedy 🔗 Politics 🔗 Biography/politics and government 🔗 Politics of the United Kingdom

Lord Buckethead is a satirical political candidate who has stood in four British general elections since 1987, portrayed by several individuals.

The character, an intergalactic villain similar to the Star Wars character Darth Vader, was created by American filmmaker Todd Durham for his 1984 science fiction film Hyperspace. British video distributor Mike Lee adopted Lord Buckethead to stand in the 1987 UK general election and again in the 1992 general election. The character went unused until comedian Jonathan Harvey stood as Lord Buckethead in the 2017 general election; his televised appearance standing next to prime minister Theresa May went viral, drawing media coverage and an online following.

After the 2017 election, Durham asserted his ownership of the character and displaced Harvey. With Durham's authorisation, Lord Buckethead returned in 2019, now played by David Hughes; he appeared at People’s Vote rallies calling for a second Brexit referendum, and stood in the 2019 general election representing the Monster Raving Loony Party. Harvey also stood, using a new character, Count Binface.