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πŸ”— Starlight (Interstellar Probe)

πŸ”— Spaceflight

Project Starlight is a research project of the University of California, Santa Barbara to develop a fleet of laser beam-propelled interstellar probes and sending them to a star neighboring the Solar System, potentially Alpha Centauri. The project aims to send organisms on board the probe.

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πŸ”— Today Is Norwegian Constitution Day

πŸ”— Norway

Norwegian Constitution Day is the national day of Norway and is an official public holiday observed on May 17 each year. Among Norwegians, the day is referred to simply as syttende mai (lit. "seventeenth May"), Nasjonaldagen (The National Day) or Grunnlovsdagen (The Constitution Day), although the latter is less frequent.

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πŸ”— List of oldest continuously inhabited cities

πŸ”— Archaeology πŸ”— Cities πŸ”— Dacia

This is a list of present-day cities by the time period over which they have been continuously inhabited as a city. The age claims listed are generally disputed. Differences in opinion can result from different definitions of "city" as well as "continuous habitation" and historical evidence is often disputed. Caveats (and sources) to the validity of each claim are discussed in the "Notes" column.

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πŸ”— Alcubierre drive

πŸ”— Spaceflight πŸ”— Physics πŸ”— Alternative Views πŸ”— Physics/relativity

The Alcubierre drive, Alcubierre warp drive, or Alcubierre metric (referring to metric tensor) is a speculative idea based on a solution of Einstein's field equations in general relativity as proposed by Mexican theoretical physicist Miguel Alcubierre, by which a spacecraft could achieve apparent faster-than-light travel if a configurable energy-density field lower than that of vacuum (that is, negative mass) could be created.

Rather than exceeding the speed of light within a local reference frame, a spacecraft would traverse distances by contracting space in front of it and expanding space behind it, resulting in effective faster-than-light travel. Objects cannot accelerate to the speed of light within normal spacetime; instead, the Alcubierre drive shifts space around an object so that the object would arrive at its destination faster than light would in normal space without breaking any physical laws.

Although the metric proposed by Alcubierre is consistent with the Einstein field equations, construction of such a drive is not necessarily possible. The proposed mechanism of the Alcubierre drive implies a negative energy density and therefore requires exotic matter. So if exotic matter with the correct properties cannot exist, then the drive could not be constructed. At the close of his original article, however, Alcubierre argued (following an argument developed by physicists analyzing traversable wormholes) that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement for the Alcubierre drive.

Another possible issue is that, although the Alcubierre metric is consistent with Einstein's equations, general relativity does not incorporate quantum mechanics. Some physicists have presented arguments to suggest that a theory of quantum gravity (which would incorporate both theories) would eliminate those solutions in general relativity that allow for backwards time travel (see the chronology protection conjecture) and thus make the Alcubierre drive invalid.

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πŸ”— Law of Jante

πŸ”— Denmark πŸ”— Sociology πŸ”— Norway πŸ”— Sweden

The Law of Jante (Danish: Janteloven) is a code of conduct known in Nordic countries that characterizes not conforming, doing things out of the ordinary, or being overtly personally ambitious as unworthy and inappropriate. The attitudes were first formulated in the form of the ten rules of Jante Law by the Dano-Norwegian author Aksel Sandemose in his satirical novel A Fugitive Crosses His Tracks (En flyktning krysser sitt spor, 1933), but the actual attitudes themselves are older. Sandemose portrays the fictional small Danish town Jante, which he modelled upon his native town NykΓΈbing Mors in the 1930s, where nobody was anonymous, which is typical of all small towns and communities.

Used generally in colloquial speech in the Nordic countries as a sociological term to denote a social attitude of disapproval towards expressions of individuality and personal success, it emphasizes adherence to the collective.

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πŸ”— List of mass shootings in the United States in 2022

πŸ”— United States πŸ”— Disaster management πŸ”— Crime πŸ”— Death πŸ”— Lists πŸ”— Politics πŸ”— Politics/American politics πŸ”— Years πŸ”— United States/U.S. history πŸ”— Current events πŸ”— Politics/Gun politics

This is a list of shootings in the United States that have occurred in 2022. Mass shootings are incidents involving several victims of firearm-related violence. The precise inclusion criteria are disputed, and there is no broadly accepted definition.

Gun Violence Archive, a nonprofit research group, run by Tracy Holtan, that tracks shootings and their characteristics in the United States, defines a mass shooting as an incident in which four or more people, excluding the perpetrator(s), are shot in one location at roughly the same time. The Congressional Research Service narrows that definition, limiting it to "public mass shootings", defined by four or more victims killed, excluding any victims who survive. The Washington Post and Mother Jones use similar definitions, with the latter acknowledging that their definition "is a conservative measure of the problem", as many shootings with fewer fatalities occur. The crowdsourced Mass Shooting Tracker project has the most expansive definition of four or more shot in any incident, including the perpetrator in the victim inclusion criteria.

A 2019 study of mass shootings published in the journal Injury Epidemiology recommended developing "a standard definition that considers both fatalities and nonfatalities to most appropriately convey the burden of mass shootings on gun violence." The authors of the study further suggested that "the definition of mass shooting should be four or more people, excluding the shooter, who are shot in a single event regardless of the motive, setting or number of deaths."

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πŸ”— Baum-Welch Algorithm

πŸ”— Computing πŸ”— Mathematics πŸ”— Statistics πŸ”— Molecular Biology πŸ”— Molecular Biology/Computational Biology

In electrical engineering, statistical computing and bioinformatics, the Baum–Welch algorithm is a special case of the expectation–maximization algorithm used to find the unknown parameters of a hidden Markov model (HMM). It makes use of the forward-backward algorithm to compute the statistics for the expectation step.

πŸ”— Namecoin

πŸ”— Computing πŸ”— Computing/Software πŸ”— Numismatics πŸ”— Software πŸ”— Software/Computing πŸ”— Numismatics/Cryptocurrency πŸ”— Cryptocurrency πŸ”— Computing/Computer Security

Namecoin (Symbol: β„• or NMC) is a cryptocurrency originally forked from bitcoin software. It is based on the code of bitcoin and uses the same proof-of-work algorithm. Like bitcoin, it is limited to 21 million coins.

Namecoin can store data within its own blockchain transaction database. The original proposal for Namecoin called for Namecoin to insert data into bitcoin's blockchain directly. Anticipating scaling difficulties with this approach, a shared proof-of-work (POW) system was proposed to secure new cryptocurrencies with different use cases.

Namecoin's flagship use case is the censorship-resistant top level domain .bit, which is functionally similar to .com or .net domains but is independent of ICANN, the main governing body for domain names.

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πŸ”— Wireless USB

πŸ”— Computing πŸ”— Computing/Networking

Wireless USB was a short-range, high-bandwidth wireless radio communication protocol created by the Wireless USB Promoter Group which intended to increase the availability of general USB-based technologies. It is unrelated to Wi-Fi. It was maintained by the WiMedia Alliance which ceased operations in 2009. Wireless USB is sometimes abbreviated as "WUSB", although the USB Implementers Forum discouraged this practice and instead prefers to call the technology Certified Wireless USB to distinguish it from the competing UWB standard.

Wireless USB was based on the (now defunct) WiMedia Alliance's Ultra-WideBand (UWB) common radio platform, which is capable of sending 480Β Mbit/s at distances up to 3 metres (9.8Β ft) and 110Β Mbit/s at up to 10 metres (33Β ft). It was designed to operate in the 3.1 to 10.6Β GHz frequency range, although local regulatory policies may restrict the legal operating range in some countries.

The standard is now obsolete, and no new hardware has been produced for many years.

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πŸ”— As We May Think

πŸ”— Computing πŸ”— Libraries

"As We May Think" is a 1945 essay by Vannevar Bush which has been described as visionary and influential, anticipating many aspects of information society. It was first published in The Atlantic in July 1945 and republished in an abridged version in September 1945β€”before and after the atomic bombings of Hiroshima and Nagasaki. Bush expresses his concern for the direction of scientific efforts toward destruction, rather than understanding, and explicates a desire for a sort of collective memory machine with his concept of the memex that would make knowledge more accessible, believing that it would help fix these problems. Through this machine, Bush hoped to transform an information explosion into a knowledge explosion.

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