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🔗 Earth as a nuclear furnace (geothermal heat is mostly from radioactive decay)

🔗 Geology

Geothermal gradient is the rate of increasing temperature with respect to increasing depth in Earth's interior. Away from tectonic plate boundaries, it is about 25–30 °C/km (72–87 °F/mi) of depth near the surface in most of the world. Strictly speaking, geo-thermal necessarily refers to Earth but the concept may be applied to other planets.

Earth's internal heat comes from a combination of residual heat from planetary accretion, heat produced through radioactive decay, latent heat from core crystallization, and possibly heat from other sources. The major heat-producing isotopes in Earth are potassium-40, uranium-238, uranium-235, and thorium-232. At the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa (3.6 million atm). Because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher. Heat production was twice that of present-day at approximately 3 billion years ago, resulting in larger temperature gradients within the Earth, larger rates of mantle convection and plate tectonics, allowing the production of igneous rocks such as komatiites that are no longer formed.

🔗 Potemkin Village

🔗 Russia 🔗 History 🔗 Skepticism 🔗 Sociology 🔗 Urban studies and planning 🔗 Russia/language and literature of Russia 🔗 Cities 🔗 European history 🔗 Russia/history of Russia

In politics and economics, a Potemkin village is any construction (literal or figurative) whose sole purpose is to provide an external façade to a country which is faring poorly, making people believe that the country is faring better, although statistics and charts would state otherwise. The term comes from stories of a fake portable village built solely to impress Empress Catherine II by her former lover Grigory Potemkin, during her journey to Crimea in 1787. While modern historians claim accounts of this portable village are exaggerated, the original story was that Potemkin erected phony portable settlements along the banks of the Dnieper River in order to impress the Russian Empress; the structures would be disassembled after she passed, and re-assembled farther along her route to be viewed again as if another example. The term is a translation of the Russian: потёмкинские деревни (IPA: /pɐˈtʲɵmkʲɪnskʲɪɪ dʲɪˈrʲɛvnʲɪ/; romanization: potyómkinskiye derévni).

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🔗 Alcubierre drive

🔗 Spaceflight 🔗 Physics 🔗 Alternative Views 🔗 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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🔗 ArcaOS is a proprietary operating system based on OS/2

🔗 Technology 🔗 Computing 🔗 Computing/Software 🔗 Software 🔗 Software/Computing 🔗 C/C++ 🔗 Java

ArcaOS is a proprietary operating system based on OS/2, developed and marketed by Arca Noae, LLC under license from IBM. It was first released in 2017 and builds on OS/2 Warp 4.52 by adding support for new hardware, fixing defects and limitations in the operating system, and by including new applications and tools, and includes some Linux/Unix tool compatibility. It is targeted at professional users who need to run their OS/2 applications on new hardware, as well as personal users of OS/2.

Like OS/2 Warp, ArcaOS is a 32-bit single user, multiprocessing, preemptive multitasking operating system for the x86 architecture. It is supported on both physical hardware and virtual machine hypervisors.

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🔗 Gödel's Loophole

🔗 United States/U.S. Government 🔗 United States 🔗 Biography 🔗 Philosophy 🔗 Philosophy/Logic 🔗 Biography/science and academia 🔗 Philosophy/Contemporary philosophy 🔗 Philosophy/Philosophers 🔗 United States/U.S. history

Gödel's Loophole is a "inner contradiction" in the Constitution of the United States which Austrian-German-American logician, mathematician, and analytic philosopher Kurt Gödel claimed to have discovered in 1947. The flaw would have allowed the American democracy to be legally turned into a dictatorship. Gödel told his friend Oskar Morgenstern about the existence of the flaw and Morgenstern told Albert Einstein about it at the time, but Morgenstern, in his recollection of the incident in 1971, never mentioned the exact problem as Gödel saw it. This has led to speculation about the precise nature of what has come to be called "Gödel's Loophole". It has been called "one of the great unsolved problems of constitutional law."

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🔗 How a Buffer Overflow Works

🔗 Computing 🔗 Computer Security 🔗 Computer Security/Computing 🔗 Computing/Software

In information security and programming, a buffer overflow, or buffer overrun, is an anomaly where a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory locations.

Buffers are areas of memory set aside to hold data, often while moving it from one section of a program to another, or between programs. Buffer overflows can often be triggered by malformed inputs; if one assumes all inputs will be smaller than a certain size and the buffer is created to be that size, then an anomalous transaction that produces more data could cause it to write past the end of the buffer. If this overwrites adjacent data or executable code, this may result in erratic program behavior, including memory access errors, incorrect results, and crashes.

Exploiting the behavior of a buffer overflow is a well-known security exploit. On many systems, the memory layout of a program, or the system as a whole, is well defined. By sending in data designed to cause a buffer overflow, it is possible to write into areas known to hold executable code and replace it with malicious code, or to selectively overwrite data pertaining to the program's state, therefore causing behavior that was not intended by the original programmer. Buffers are widespread in operating system (OS) code, so it is possible to make attacks that perform privilege escalation and gain unlimited access to the computer's resources. The famed Morris worm in 1988 used this as one of its attack techniques.

Programming languages commonly associated with buffer overflows include C and C++, which provide no built-in protection against accessing or overwriting data in any part of memory and do not automatically check that data written to an array (the built-in buffer type) is within the boundaries of that array. Bounds checking can prevent buffer overflows, but requires additional code and processing time. Modern operating systems use a variety of techniques to combat malicious buffer overflows, notably by randomizing the layout of memory, or deliberately leaving space between buffers and looking for actions that write into those areas ("canaries").

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🔗 Social Facilitation

🔗 Philosophy 🔗 Politics 🔗 Psychology 🔗 Marketing & Advertising 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Epistemology 🔗 Sociology 🔗 Education

Social facilitation is defined as improvement or decrease in individual performance when working with other people rather than alone.

In addition to working together with other people, social facilitation also occurs in the mere presence of other people. Previous research has found that individual performance is improved by coaction, performing a task in the presence of others who are performing a similar task, and having an audience while performing a certain task. An example of coaction triggering social facilitation can be seen in instances where a cyclist's performance is improved when cycling along with other cyclists as compared to cycling alone. An instance where having an audience triggers social facilitation can be observed where a weightlifter lifts heavier weight in the presence of an audience. Social facilitation has occasionally been attributed to the fact that certain people are more susceptible to social influence, with the argument that personality factors can make these people more aware of evaluation.

The Yerkes-Dodson law, when applied to social facilitation, states that "the mere presence of other people will enhance the performance in speed and accuracy of well-practiced tasks, but will degrade in the performance of less familiar tasks." Compared to their performance when alone, when in the presence of others they tend to perform better on simple or well-rehearsed tasks and worse on complex or new ones.

The audience effect attempts to explain psychologically why the presence of an audience leads to people performing tasks better in some cases and worse in others. This idea was further explored when some studies showed that the presence of a passive audience facilitated the better performance of a simple task, while other studies showed that the presence of a passive audience inhibited the performance of a more difficult task or one that was not well practiced, possibly due to psychological pressure or stress. (See Yerkes–Dodson law.)

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🔗 False Banana Tree

🔗 Food and drink 🔗 Plants

Ensete ventricosum, commonly known as enset or ensete, Ethiopian banana, Abyssinian banana, and false banana, is an herbaceous species of flowering plant in the banana family Musaceae. The domesticated form of the plant is only cultivated in Ethiopia, where it provides the staple food for approximately 20 million people. The name Ensete ventricosum was first published in 1948 in the Kew Bulletin, 1947, p. 101. Its synonyms include Musa arnoldiana De Wild., Musa ventricosa Welw. and Musa ensete J.F.Gmel. In its wild form, it is native to the eastern edge of the Great African Plateau, extending northwards from South Africa through Mozambique, Zimbabwe, Malawi, Kenya, Uganda and Tanzania to Ethiopia, and west to the Congo, being found in high rainfall forests on mountains, and along forested ravines and streams.

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🔗 Choking game, also known as the fainting game

🔗 Medicine

The choking game (also known as the fainting game and a wide variety of slang terms) refers to intentionally cutting off oxygen to the brain with the goal of inducing temporary loss of consciousness and euphoria.

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🔗 Abraham Lempel (LZ77) has died

🔗 Biography 🔗 Biography/science and academia 🔗 Israel

Abraham Lempel (Hebrew: אברהם למפל, 10 February 1936 – 4 February 2023) was an Israeli computer scientist and one of the fathers of the LZ family of lossless data compression algorithms.