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🔗 United States 🔗 Biography 🔗 Biography/science and academia 🔗 United States/Ohio 🔗 University of California

Elwyn Ralph Berlekamp (September 6, 1940 – April 9, 2019) was an American mathematician known for his work in computer science, coding theory and combinatorial game theory. He was a professor emeritus of mathematics and EECS at the University of California, Berkeley.

Berlekamp was the inventor of an algorithm to factor polynomials, and was one of the inventors of the Berlekamp–Welch algorithm and the Berlekamp–Massey algorithms, which are used to implement Reed–Solomon error correction.

Berlekamp had also been active in money management. In 1986, he began information-theoretic studies of commodity and financial futures.

🔗 Computing 🔗 Computing/Software

In computer programming, a poltergeist (or gypsy wagon) is a short-lived, typically stateless object used to perform initialization or to invoke methods in another, more permanent class. It is considered an anti-pattern. The original definition is by Michael Akroyd 1996 - Object World West Conference:

"As a gypsy wagon or a poltergeist appears and disappears mysteriously, so does this short lived object. As a consequence the code is more difficult to maintain and there is unnecessary resource waste. The typical cause for this anti-pattern is poor object design."

A poltergeist can often be identified by its name; they are often called "manager_", "controller_", "supervisor", "start_process", etc.

Sometimes, poltergeist classes are created because the programmer anticipated the need for a more complex architecture. For example, a poltergeist arises if the same method acts as both the client and invoker in a command pattern, and the programmer anticipates separating the two phases. However, this more complex architecture may actually never materialize.

Poltergeists should not be confused with long-lived, state-bearing objects of a pattern such as model–view–controller, or tier-separating patterns such as business-delegate.

To remove a poltergeist, delete the class and insert its functionality in the invoked class, possibly by inheritance or as a mixin.

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

netcat (often abbreviated to nc) is a computer networking utility for reading from and writing to network connections using TCP or UDP. The command is designed to be a dependable back-end that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and investigation tool, since it can produce almost any kind of connection its user could need and has a number of built-in capabilities.

Its list of features includes port scanning, transferring files, and port listening, and it can be used as a backdoor.

🔗 Mathematics

Pentagramma mirificum (Latin for miraculous pentagram) is a star polygon on a sphere, composed of five great circle arcs, all of whose internal angles are right angles. This shape was described by John Napier in his 1614 book Mirifici logarithmorum canonis descriptio (Description of the wonderful rule of logarithms) along with rules that link the values of trigonometric functions of five parts of a right spherical triangle (two angles and three sides). The properties of pentagramma mirificum were studied, among others, by Carl Friedrich Gauss.

🔗 Technology 🔗 France

The Rue de l'Avenir (transl. Street of the future) was an electric moving walkway installed at the 1900 Exposition Universelle in Paris. It ran along the edge of the Exposition site, from the Esplanade of Les Invalides to the Champ de Mars, passing through nine stations along the way, where passengers could board. It was designed by architect Joseph Lyman Silsbee and engineer Max E. Schmidt, designers of The Great Wharf Moving Sidewalk installed at the 1893 World's Fair in Chicago, the first-ever moving walkway.

🔗 Medicine 🔗 Medicine/Pulmonology 🔗 Physiology 🔗 Scuba diving 🔗 Physiology/respiratory

Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid (such as a perfluorocarbon), rather than breathing air.

This requires certain physical properties such as respiratory gas solubility, density, viscosity, vapor pressure, and lipid solubility which some, but not all, perfluorochemicals (perfluorocarbon) have. Thus, it is critical to choose the appropriate PFC for a specific biomedical application, such as liquid ventilation, drug delivery or blood substitutes. The physical properties of PFC liquids vary substantially; however, the one common property is their high solubility for respiratory gases. In fact, these liquids carry more oxygen and carbon dioxide than blood.

In theory, liquid breathing could assist in the treatment of patients with severe pulmonary or cardiac trauma, especially in pediatric cases. Liquid breathing has also been proposed for use in deep diving and space travel. Despite some recent advances in liquid ventilation, a standard mode of application has not yet been established.

🔗 Aviation 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 England

British Airways Flight 5390 was a flight from Birmingham Airport in England for Málaga Airport in Spain that suffered explosive decompression, with no loss of life, shortly after takeoff on 10 June 1990. An improperly installed windscreen panel separated from its frame, causing the plane's captain to be blown partially out of the aircraft. With the captain pinned against the window frame for twenty minutes, the first officer landed at Southampton Airport.

🔗 California 🔗 Companies 🔗 California/San Francisco Bay Area 🔗 Computing 🔗 Open 🔗 Mozilla

The Mozilla Corporation (stylized as moz://a) is a wholly owned subsidiary of the Mozilla Foundation that coordinates and integrates the development of Internet-related applications such as the Firefox web browser, by a global community of open-source developers, some of whom are employed by the corporation itself. The corporation also distributes and promotes these products. Unlike the non-profit Mozilla Foundation, and the Mozilla open source project, founded by the now defunct Netscape Communications Corporation, the Mozilla Corporation is a taxable entity. The Mozilla Corporation reinvests all of its profits back into the Mozilla projects. The Mozilla Corporation's stated aim is to work towards the Mozilla Foundation's public benefit to "promote choice and innovation on the Internet."

A MozillaZine article explained:

The Mozilla Foundation will ultimately control the activities of the Mozilla Corporation and will retain its 100 percent ownership of the new subsidiary. Any profits made by the Mozilla Corporation will be invested back into the Mozilla project. There will be no shareholders, no stock options will be issued and no dividends will be paid. The Mozilla Corporation will not be floating on the stock market and it will be impossible for any company to take over or buy a stake in the subsidiary. The Mozilla Foundation will continue to own the Mozilla trademarks and other intellectual property and will license them to the Mozilla Corporation. The Foundation will also continue to govern the source code repository and control who is allowed to check in.

🔗 Technology 🔗 Architecture

A Matrioshka brain is a hypothetical megastructure of immense computational capacity powered by a Dyson sphere. It was proposed in 1997 by Robert J. Bradbury (1956–2011). It is an example of a Class B stellar engine, employing the entire energy output of a star to drive computer systems. This concept derives its name from the nesting Russian Matryoshka dolls. The concept was deployed by Bradbury in the anthology Year Million: Science at the Far Edge of Knowledge.