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🔗 Philosophy 🔗 Philosophy/Logic

The raven paradox, also known as Hempel's paradox, Hempel's ravens, or rarely the paradox of indoor ornithology, is a paradox arising from the question of what constitutes evidence for a statement. Observing objects that are neither black nor ravens may formally increase the likelihood that all ravens are black even though, intuitively, these observations are unrelated.

This problem was proposed by the logician Carl Gustav Hempel in the 1940s to illustrate a contradiction between inductive logic and intuition.

🔗 Neuroscience

Saccadic masking, also known as (visual) saccadic suppression, is the phenomenon in visual perception where the brain selectively blocks visual processing during eye movements in such a way that neither the motion of the eye (and subsequent motion blur of the image) nor the gap in visual perception is noticeable to the viewer.

The phenomenon was first described by Erdmann and Dodge in 1898, when it was noticed during unrelated experiments that an observer could never see the motion of their own eyes. This can easily be duplicated by looking into a mirror, and looking from one eye to another. The eyes can never be observed in motion, yet an external observer clearly sees the motion of the eyes.

The phenomenon is often used to help explain a temporal illusion by the name of chronostasis, which momentarily occurs following a rapid eye-movement.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Computer science

Flashsort is a distribution sorting algorithm showing linear computational complexity ${\displaystyle O(n)}$ for uniformly distributed data sets and relatively little additional memory requirement. The original work was published in 1998 by Karl-Dietrich Neubert.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Military history/Medieval warfare

A rondel dagger or roundel dagger was a type of stiff-bladed dagger in Europe in the late Middle Ages (from the 14th century onwards), used by a variety of people from merchants to knights. It was worn at the waist and might be used as a utility tool, or worn into battle or in a jousting tournament as a side arm.

The rondel dagger featured a long, slim steel blade with a round or circular hand guard and pommel. Designed for close-quarter combat, it was effective in puncturing and bursting mail armor links and penetrating weak points in plate armor. The dagger evolved from the early knightly dagger and became the standard side-arm for knights in the 15th century. It was used as a backup weapon for hand-to-hand fighting and as a tool to force surrender, as captured knights could be ransomed. The rondel dagger also gained popularity among the middle class in the 15th century. Various combat techniques involving the rondel dagger can be found in Hans Talhoffer's combat manuals from the 1440s to 1460s.

🔗 Energy 🔗 Stanford University/SRI International 🔗 Stanford University

The cubic mile of oil (CMO) is a unit of energy, aiming to give the general public an understanding of large quantities of energy. It is approximately equal to 1.6×10²⁰ joule. It was created by Hew Crane of SRI International to aid in public understanding of global-scale energy consumption and resources.

Large scale sources of energy include wind, solar photovoltaic, solar thermal, nuclear, hydroelectric, oil, coal, natural gas, geothermal, and biomass (primarily the burning of wood). Traditionally, many different units are commonly used to measure these sources (e.g., joules, BTUs, kilowatt hours, therms) but only some of them are familiar to a global general public, and some argue that fewer are needed and a standard should be chosen. Still, these common energy units are mainly sized for everyday activities, for example a joule is the energy required to lift a small apple one metre vertically. For regional, national, and global scales, larger energy units, such as exajoule, terawatt-hour, billion barrels of oil equivalent (BBOE) and quad are used. Derived by multiplying the small common units by large powers of ten these larger units pose additional conceptual difficulties for many citizens.

Crane intended the cubic mile of oil to provide a visualizable scale for comparing the contributions of these diverse energy components as a percentage of total worldwide, energy use.

In 2005, the global economy was consuming approximately 30 billion barrels (4.8 billion cubic metres; 1.3 trillion US gallons) of oil each year. Numbers of this magnitude are difficult to conceive by most people. The volume occupied by 1 trillion US gallons (3.8 billion cubic metres) is about 1 cubic mile (4.2 billion cubic metres). Crane felt that a cubic mile would be an easier concept for the general public than a trillion gallons.

🔗 Computing

The Andrew File System (AFS) is a distributed file system which uses a set of trusted servers to present a homogeneous, location-transparent file name space to all the client workstations. It was developed by Carnegie Mellon University as part of the Andrew Project. Originally named "Vice", "Andrew" refers to Andrew Carnegie and Andrew Mellon. Its primary use is in distributed computing.

🔗 Video games

The Interton Video Computer 4000 (officially abbreviated as Interton VC 4000) is an 8-bit ROM cartridge-based second-generation home video game console that was released in Germany, England, France, Spain, Austria, the Netherlands and Australia in 1978 by German hearing aid manufacturer Interton. The console is quite obscure outside Germany, but many software-compatible systems can be found in numerous European countries (see versions of the 1292 Advanced Programmable Video System). The console is the successor of the Interton Video 3001 and was sold for 298DM and discontinued in 1983.

It is unknown if Interton designed and produced the Interton VC 4000 within their own rights, or if they were sold the rights to design and produce it. This is because many other foreign brands have produced "clones" of this system in the preceding years.

The Interton VC 4000's power comes from a Signetics 2650 CPU (which is the same as an Arcadia 2001) and a Signetics 2636 gaming video controller. Both controllers contain a 12-button keypad, two fire buttons, and a joystick. Inside the systems control panel, there are four different buttons: the ON/OFF switch, RESET, SELECT, and START.

🔗 Physics 🔗 History of Science

The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century to early 20th century classical physics that an ideal black body at thermal equilibrium would emit an unbounded quantity of energy as wavelength decreased into the ultraviolet range.^: 6–7 The term "ultraviolet catastrophe" was first used in 1911 by Paul Ehrenfest, but the concept originated with the 1900 statistical derivation of the Rayleigh–Jeans law.

The phrase refers to the fact that the empirically derived Rayleigh–Jeans law, which accurately predicted experimental results at large wavelengths, failed to do so for short wavelengths. (See the image for further elaboration.) As the theory diverged from empirical observations when these frequencies reached the ultraviolet region of the electromagnetic spectrum, there was a problem. This problem was later found to be due to a property of quanta as proposed by Max Planck: There could be no fraction of a discrete energy package already carrying minimal energy.

Since the first use of this term, it has also been used for other predictions of a similar nature, as in quantum electrodynamics and such cases as ultraviolet divergence.

🔗 Computing 🔗 Computer Security 🔗 Computer Security/Computing 🔗 Computing/Software 🔗 Cryptography 🔗 Cryptography/Computer science

Pretty Good Privacy (PGP) is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, e-mails, files, directories, and whole disk partitions and to increase the security of e-mail communications. Phil Zimmermann developed PGP in 1991.

PGP and similar software follow the OpenPGP, an open standard of PGP encryption software, standard (RFC 4880) for encrypting and decrypting data.

🔗 Serbia 🔗 Yugoslavia 🔗 Military history 🔗 Correction and Detention Facilities 🔗 Military history/World War II 🔗 Military history/Balkan military history 🔗 Croatia 🔗 Military history/European military history

Jasenovac was a concentration and extermination camp established in Slavonia by the authorities of the Independent State of Croatia (NDH) in occupied Yugoslavia during World War II. The concentration camp, one of the ten largest in Europe, was established and operated by the governing Ustaše regime, which was the only quisling regime in occupied Europe to operate extermination camps solely on their own for Jews and other ethnic groups.

It was established in August 1941 in marshland at the confluence of the Sava and Una rivers near the village of Jasenovac, and was dismantled in April 1945. It was "notorious for its barbaric practices and the large number of victims". Unlike German Nazi-run camps, Jasenovac "specialized in one-on-one violence of a particularly brutal kind" and prisoners were primarily murdered manually with the use of blunt objects such as knives, hammers and axes.

In Jasenovac the majority of victims were ethnic Serbs (as part of the Genocide of the Serbs); others were Jews (The Holocaust), Roma (The Porajmos), and some political dissidents. Jasenovac was a complex of five subcamps spread over 210 km² (81 sq mi) on both banks of the Sava and Una rivers. The largest camp was the "Brickworks" camp at Jasenovac, about 100 km (62 mi) southeast of Zagreb. The overall complex included the Stara Gradiška sub-camp, the killing grounds across the Sava river at Gradina Donja, five work farms, and the Uštica Roma camp.

During and since World War II, there has been much debate and controversy regarding the number of victims killed at the Jasenovac concentration camp complex during its more than three-and-a-half years of operation. After the war, a figure of 700,000 reflected the "conventional wisdom". Since 2002, the Museum of Victims of Genocide in Belgrade has no longer defended the figure of 700,000 to 1 million victims of the camp. In 2005, Dragan Cvetković, a researcher from the Museum, and a Croatian co-author published a book on wartime losses in the NDH which gave a figure of approximately 100,000 victims of Jasenovac. The United States Holocaust Memorial Museum (USHMM) in Washington, D.C. presently estimates that the Ustaše regime murdered between 77,000 and 99,000 people in Jasenovac between 1941 and 1945.